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Bibliography on: Wolbachia

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Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 27 Sep 2020 at 01:36 Created: 

Wolbachia

WIKIPEDIA: Wolbachia is a genus of bacteria which "infects" (usually as intracellular symbionts) arthropod species, including a high proportion of insects, as well as some nematodes. It is one of the world's most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere. Its interactions with its hosts are often complex, and in some cases have evolved to be mutualistic rather than parasitic. Some host species cannot reproduce, or even survive, without Wolbachia infection. One study concluded that more than 16% of neotropical insect species carry bacteria of this genus, and as many as 25 to 70 percent of all insect species are estimated to be potential hosts. Wolbachia also harbor a temperate bacteriophage called WO. Comparative sequence analyses of bacteriophage WO offer some of the most compelling examples of large-scale horizontal gene transfer between Wolbachia coinfections in the same host. It is the first bacteriophage implicated in frequent lateral transfer between the genomes of bacterial endosymbionts. Gene transfer by bacteriophages could drive significant evolutionary change in the genomes of intracellular bacteria that were previously considered highly stable or prone to loss of genes overtime. Outside of insects, Wolbachia infects a variety of isopod species, spiders, mites, and many species of filarial nematodes (a type of parasitic worm), including those causing onchocerciasis ("River Blindness") and elephantiasis in humans as well as heartworms in dogs. Not only are these disease-causing filarial worms infected with Wolbachia, but Wolbachia seem to play an inordinate role in these diseases. A large part of the pathogenicity of filarial nematodes is due to host immune response toward their Wolbachia. Elimination of Wolbachia from filarial nematodes generally results in either death or sterility of the nematode.

Created with PubMed® Query: wolbachia NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2020-09-25

Shropshire JD, Leigh B, SR Bordenstein (2020)

Symbiont-mediated cytoplasmic incompatibility: what have we learned in 50 years?.

eLife, 9: pii:61989.

Cytoplasmic incompatibility (CI) is the most common symbiont-induced reproductive manipulation. Specifically, symbiont-induced sperm modifications cause catastrophic mitotic defects in the fertilized embryo and ensuing lethality in crosses between symbiotic males and either aposymbiotic females or females harboring a different symbiont strain. However, if the female carries the same symbiont strain, then embryos develop properly, thereby imparting a relative fitness benefit to symbiont-transmitting mothers. Thus, CI drives maternally-transmitted bacteria to high frequencies in arthropods worldwide. In the past two decades, CI experienced a boom in interest due to its (i) deployment in worldwide efforts to curb mosquito-borne diseases, (ii) causation by bacteriophage genes, cifA and cifB, that modify sexual reproduction, and (iii) important impacts on arthropod speciation. This review serves as a gateway to experimental, conceptual, and quantitative themes of CI and outlines significant gaps in understanding CI's mechanism that are ripe for investigation from diverse subdisciplines in the life sciences.

RevDate: 2020-09-24

Price TAR, Windbichler N, Unckless RL, et al (2020)

Resistance to natural and synthetic gene drive systems.

Journal of evolutionary biology [Epub ahead of print].

Scientists are rapidly developing synthetic gene drive elements intended for release into natural populations. These are intended to control or eradicate disease vectors and pests, or to spread useful traits through wild populations for disease control or conservation purposes. However, a crucial problem for gene drives is the evolution of resistance against them, preventing their spread. Understanding the mechanisms by which populations might evolve resistance is essential for engineering effective gene drive systems. This review summarizes our current knowledge of drive resistance in both natural and synthetic gene drives. We explore how insights from naturally occurring and synthetic drive systems can be integrated to improve the design of gene drives, better predict the outcome of releases and understand genomic conflict in general.

RevDate: 2020-09-23

Guo Y, Khan J, Zheng XY, et al (2020)

Wolbachia increase germ cell mitosis to enhance the fecundity of Laodelphax striatellus.

Insect biochemistry and molecular biology pii:S0965-1748(20)30160-0 [Epub ahead of print].

Wolbachia are intracellular bacteria that infect a wide range of invertebrates and have evolved various strategies to alter host reproduction for their own survival and dissemination. In small brown planthopper Laodelphax striatellus, Wolbachia-infected females lay more eggs than uninfected females. Our previous study has shown that Wolbachia are abundant in ovarian cells of L. striatellus and change the number of apoptotic nurse cells in a caspase-dependent manner to provide nutrition for oogenesis. The cellular and molecular bases of the Wolbachia-mediated alterations in L. striatellus oogenesis remain largely unknown. Here, we investigated whether germ cell mitosis, which has been implicated in determination of egg production rates, influences the interaction between fecundity and Wolbachia in L. striatellus. We used an anti-phospho-histone 3 (pH3) antibody to label and visualize mitotic cells. Microscopic observations indicated that the Wolbachia strain wStri increased the number of ovarioles that contained mitotic germ cells. The increased fecundity of Wolbachia-infected females was a result of mitosis of germ cells; the frequency of germ cell mitosis was much higher in infected females than in uninfected females. In addition, mitosis inhibition by Cdc20, CDK1, and CycB messenger RNA interference in Wolbachia-infected L. striatellus markedly decreased egg numbers. Live Wolbachia recolonization enhanced the egg production of uninfected L. striatellus by directly affecting mitosis regulators. Together, these data suggest that wStri might increase germ cell mitosis to enhance the fecundity of L. striatellus in a mitosis-regulating manner. Our findings establish a link between Wolbachia-induced mitosis and Wolbachia-mediated egg production effects.

RevDate: 2020-09-19

Koh C, Islam MN, Ye YH, et al (2020)

Dengue virus dominates lipid metabolism modulations in Wolbachia-coinfected Aedes aegypti.

Communications biology, 3(1):518 pii:10.1038/s42003-020-01254-z.

Competition between viruses and Wolbachia for host lipids is a proposed mechanism of Wolbachia-mediated virus blocking in insects. Yet, the metabolomic interaction between virus and symbiont within the mosquito has not been clearly defined. We compare the lipid profiles of Aedes aegypti mosquitoes bearing mono- or dual-infections of the Wolbachia wMel strain and dengue virus serotype 3 (DENV3). We found metabolic signatures of infection-induced intracellular events but little evidence to support direct competition between Wolbachia and virus for host lipids. Lipid profiles of dual-infected mosquitoes resemble those of DENV3 mono-infected mosquitoes, suggesting virus-driven modulation dominates over that of Wolbachia. Interestingly, knockdown of key metabolic enzymes suggests cardiolipins are host factors for DENV3 and Wolbachia replication. These findings define the Wolbachia-DENV3 metabolic interaction as indirectly antagonistic, rather than directly competitive, and reveal new research avenues with respect to mosquito × virus interactions at the molecular level.

RevDate: 2020-09-18

Xia X, Peng CW, Cui JR, et al (2020)

Wolbachia affects reproduction in the spider mite Tetranychus truncatus (Acari: Tetranychidae) by regulating chorion protein S38-like and Rop.

Insect molecular biology [Epub ahead of print].

Wolbachia-induced reproductive regulation in hosts has been used to control pest populations, but little is known about the molecular mechanism underlying Wolbachia regulation of host genes. Here, reproductive regulation by Wolbachia in the spider mite Tetranychus truncatus was studied at the molecular level. Infection with Wolbachia resulted in decreasing oviposition and cytoplasmic incompatibility in T. truncatus. Further RNA-seq revealed genes regulated by Wolbachia in T. truncatus. Real-time quantitative polymerase chain reaction (qPCR) showed that genes including chorion protein S38-like and Rop were down-regulated by Wolbachia. RNA interference (RNAi) of chorion protein S38-like and Rop in Wolbachia-uninfected T. truncatus decreased oviposition, which was consistent with Wolbachia-induced oviposition decrease. Interestingly, suppressing Rop in Wolbachia-infected T. truncatus led to increased Wolbachia titers in eggs; however, this did not occur after RNAi of chorion protein S38-like. This is the first study to show that chorion protein S38-like and Rop facilitate Wolbachia-mediated changes in T. truncatus fertility. In addition, RNAi of Rop turned the body color of Wolbachia-uninfected T. truncatus black, which indicates that the role of Rop is not limited to reproductive regulation of T. truncatus.

RevDate: 2020-09-19

Arham AF, Amin L, Mustapa MAC, et al (2020)

Perceived benefits and risks: A survey data set towards Wolbachia-infected Aedes Mosquitoes in Klang Valley.

Data in brief, 32:106262.

Perceived Benefits and Risks: A survey data set towards Wolbachia-infected Aedes Mosquitoes in the Klang Valley, Malaysia. Introduction: The paper presents data collected using measures of perceived benefits, perceived risks, trust in key players, attitude towards nature versus material, attitude towards technology, religiosity, and attitude towards the Wolbachia-infected Aedes mosquitoes (WiAM) technique. The validated questionnaires were used to randomly survey targeted stakeholders in the Klang Valley, Malaysia, who had been asked to voluntarily participate in face-to-face interviews. Completed questionnaires were received from 399 respondents (adults above 18 years old) and comprised two stakeholder groups: scientists (n = 202), and the public (n = 197). The detailed findings serve numerous opportunities to examine the social acceptance of Wolbachia-infected Aedes mosquitoes, to ensure the development of policy and action plans, and to encourage further study by other researchers interested in the measures and data presented.

RevDate: 2020-09-16

Shin PT, Baptista RP, O'Neill CM, et al (2020)

Comparative sequences of the Wolbachia genomes of drug-sensitive and resistant isolates of Dirofilaria immitis.

Veterinary parasitology, 286:109225 pii:S0304-4017(20)30205-3 [Epub ahead of print].

The recent identification of isolates of D. immitis with confirmed resistance to the macrocyclic lactone preventatives presents an opportunity for comparative genomic studies using these isolates, and examining the genetic diversity within and between them. We studied the genomes of Wolbachia endosymbionts of five isolates of D. immitis maintained at the University of Georgia. Missouri and Georgia-2 are maintained as drug susceptible isolates, and JYD-27, Yazoo-2013 and Metairie-2014 are resistant to the macrocyclic lactone preventatives. We used whole genome amplification followed by Illumina-based sequencing from 8 to 12 individual microfilariae from each of the five isolates, obtaining a depth of coverage of approximately 40-75 fold for each. The Illumina sequences were used to create new genome assemblies for all the Wolbachia isolates studied. Comparisons of the Wolbachia sequences revealed more than 3000 sequence variations in each isolate. We identified 67 loci specific in resistant isolates but not in susceptible isolates, including 18 genes affected.Phylogenetic analysis suggested that the endosymbionts of the drug-susceptible isolates are more closely related to each other than to those from any of the resistant parasites. This level of variation in the Wolbachia endosymbionts of D. immitis isolates suggests a potential for selection for resistance against drugs targeting them.

RevDate: 2020-09-16

Ge C, Hu J, Zhao Z, et al (2020)

Phylogeny and Density Dynamics of Wolbachia Infection of the Health Pest Paederus fuscipes Curtis (Coleoptera: Staphylinidae).

Insects, 11(9): pii:insects11090625.

The maternally inherited obligate intracellular bacteria Wolbachia infects the reproductive tissues of a wide range of arthropods and affects host reproduction. Wolbachia is a credible biocontrol agent for reducing the impact of diseases associated with arthropod vectors. Paederus fuscipes is a small staphylinid beetle that causes dermatitis linearis and conjunctivitis in humans when they come into contact with skin. Wolbachia occur in this beetle, but their relatedness to other Wolbachia, their infection dynamics, and their potential host effects remain unknown. In this study, we report the phylogenetic position and density dynamics of Wolbachia in P. fuscipes. The phylogeny of Wolbachia based on an analysis of MLST genotyping showed that the bacteria from P. fuscipes belong to supergroup B. Quantitative PCR indicated that the infection density in adults was higher than in any other life stage (egg, larva or pupa), and that reproductive tissue in adults had the highest infection densities, with similar densities in the sexes. These findings provide a starting point for understanding the Wolbachia infection dynamics in P. fuscipes, and interactions with other components of the microbiota.

RevDate: 2020-09-16
CmpDate: 2020-09-16

Kakumanu ML, DeVries ZC, Barbarin AM, et al (2020)

Bed bugs shape the indoor microbial community composition of infested homes.

The Science of the total environment, 743:140704.

Indoor pests, and the allergens they produce, adversely affect human health. Surprisingly, however, their effects on indoor microbial communities have not been assessed. Bed bug (Cimex lectularius) infestations pose severe challenges in elderly and low-income housing. They void large amounts of liquid feces into the home environment, which might alter the indoor microbial community composition. In this study, using bed bug-infested and uninfested homes, we showed a strong impact of bed bug infestations on the indoor microbial diversity. Floor dust samples were collected from uninfested and bed bug-infested homes and their microbiomes were analyzed before and after heat interventions that eliminated bed bugs. The microbial communities of bed bug-infested homes were radically different from those of uninfested homes, and the bed bug endosymbiont Wolbachia was the major driver of this difference. After bed bugs were eliminated, the microbial community gradually shifted toward the community composition of uninfested homes, strongly implicating bed bugs in shaping the dust-associated environmental microbiome. Further studies are needed to understand the viability of these microbial communities and the potential risks that bed bug-associated microbes and their metabolites pose to human health.

RevDate: 2020-09-11

Manokaran G, Flores HA, Dickson CT, et al (2020)

Modulation of acyl-carnitines, the broad mechanism behind Wolbachia-mediated inhibition of medically important flaviviruses in Aedes aegypti.

Proceedings of the National Academy of Sciences of the United States of America pii:1914814117 [Epub ahead of print].

Wolbachia-infected mosquitoes are refractory to flavivirus infections, but the role of lipids in Wolbachia-mediated virus blocking remains to be elucidated. Here, we use liquid chromatography mass spectrometry to provide a comprehensive picture of the lipidome of Aedes aegypti (Aag2) cells infected with Wolbachia only, either dengue or Zika virus only, and Wolbachia-infected Aag2 cells superinfected with either dengue or Zika virus. This approach identifies a class of lipids, acyl-carnitines, as being down-regulated during Wolbachia infection. Furthermore, treatment with an acyl-carnitine inhibitor assigns a crucial role for acyl-carnitines in the replication of dengue and Zika viruses. In contrast, depletion of acyl-carnitines increases Wolbachia density while addition of commercially available acyl-carnitines impairs Wolbachia production. Finally, we show an increase in flavivirus infection of Wolbachia-infected cells with the addition of acyl-carnitines. This study uncovers a previously unknown role for acyl-carnitines in this tripartite interaction that suggests an important and broad mechanism that underpins Wolbachia-mediated pathogen blocking.

RevDate: 2020-09-09

Caragata EP, Dong S, Dong Y, et al (2020)

Prospects and Pitfalls: Next-Generation Tools to Control Mosquito-Transmitted Disease.

Annual review of microbiology, 74:455-475.

Mosquito-transmitted diseases, including malaria and dengue, are a major threat to human health around the globe, affecting millions each year. A diverse array of next-generation tools has been designed to eliminate mosquito populations or to replace them with mosquitoes that are less capable of transmitting key pathogens. Many of these new approaches have been built on recent advances in CRISPR/Cas9-based genome editing. These initiatives have driven the development of pathogen-resistant lines, new genetics-based sexing methods, and new methods of driving desirable genetic traits into mosquito populations. Many other emerging tools involve microorganisms, including two strategies involving Wolbachia that are achieving great success in the field. At the same time, other mosquito-associated bacteria, fungi, and even viruses represent untapped sources of new mosquitocidal or antipathogen compounds. Although there are still hurdles to be overcome, the prospect that such approaches will reduce the impact of these diseases is highly encouraging.

RevDate: 2020-09-09

Ciuca L, Vismarra A, Lebon W, et al (2020)

New insights into the biology, diagnosis and immune response to Dirofilaria repens in the canine host.

Veterinary parasitology: X, 4:100029 pii:100029.

Dogs are the primary host for Dirofilaria repens, therefore it is mandatory to accurately diagnose the canine infection and to expand our current knowledge on parasite biology and the immune response of the infected host for a better prevention.Thus, the aim of the present study was to provide new insights from experimental infections of dogs with D. repens, focusing on the evaluation of: 1) the pre-patent period and 2) the antibody response against D. repens somatic antigens and against the Wolbachia endosymbiont. Briefly, on Day 0, twenty purpose-bred Beagle dogs were experimentally infected with 50 infective larvae (L3) of D. repens. Starting from Day 58 until the last day of the study (Day 281), blood samples were collected on a monthly basis for detection of antibodies against D. repens (Dr) and recombinant Wolbachia surface protein (rWSP) by non-commercial IgG-ELISAs. Additional samples were collected on Days 220, 245 and 281 for the detection of microfilariae (mff) using the modified Knott's test and biomolecular analysis, following two PCR protocols: Gioia et al. (2010; protocol A) and Rishniw et al. (2006- protocol B). The results were analysed by univariate statistical analyses using 2 × 2 contingency tables and K Cohen was calculated to assess the agreement among all the diagnostic techniques. Overall, the outcome of the study revealed that out of the 20 dogs experimentally infected with D. repens, 16 (80 %) were microfilaraemic, 17 (85 %) were positive at DNA detection in the blood, 18 (90 %) had D. repens antibodies and 16 (80 %) had Wolbachia antibodies on the last day of the study. The overall k agreement between Knott's and PCR protocol B was 0.442 (P = 0.0001) and increased throughout the study, reaching 0.828 (P = 0.0001) on Day 281. To the authors knowledge, this is only the second study reporting antibody response to D. repens somatic antigen in experimentally infected dogs. ELISA results showed that an antibody response develops before the onset of patency, and steadily increases with time. Results would suggest that the development of an immunological response to infection could lead to application in epidemiological studies, risk assessment and as an aid in the diagnostic approach in dogs, in particular for early infections without mff.

RevDate: 2020-09-05

Lee JM, Yek SH, Wilson RF, et al (2020)

Characterisation of the Aedes albopictus (Diptera: Culicidae) holobiome: bacterial composition across land use type and mosquito sex in Malaysia.

Acta tropica pii:S0001-706X(20)30748-8 [Epub ahead of print].

Understanding the diversity and dynamics of the microbiota within the mosquito holobiome is of great importance to apprehend how the microbiota modulates various complex processes and interactions. This study examined the bacterial composition of Aedes albopictus across land use type and mosquito sex in the state of Selangor, Malaysia using 16S rRNA sequencing. The bacterial community structure in mosquitoes was found to be influenced by land use type and mosquito sex, with the environment and mosquito diet respectively identified to be the most likely sources of microbes. We found that approximately 70% of the microbiota samples were dominated by Wolbachia and removing Wolbachia from analyses revealed the relatively even composition of the remaining bacterial microbiota. Furthermore, microbial interaction network analysis highlighted the prevalence of co-exclusionary patterns in all networks regardless of land use and mosquito sex, with Wolbachia exhibiting co-exclusionary interactions with other residential bacteria such as Xanthomonas, Xenophilus and Zymobacter.

RevDate: 2020-09-04

Noh P, Oh SY, Park S, et al (2020)

Association between host wing morphology polymorphism and Wolbachia infection in Vollenhovia emeryi (Hymenoptera: Myrmicinae).

Ecology and evolution, 10(16):8827-8837 pii:ECE36582.

Many eusocial insects, including ants, show complex colony structures, distributions, and reproductive strategies. In the ant Vollenhovia emeryi Wheeler (Hymenoptera: Myrmicinae), queens and males are produced clonally, while sterile workers arise sexually, unlike other ant species and Hymenopteran insects in general. Furthermore, there is a wing length polymorphism in the queen caste. Despite its evolutionary remarkable traits, little is known about the population structure of this ant species, which may provide insight into its unique reproductive mode and polymorphic traits. We performed in-depth analyses of ant populations from Korea, Japan, and North America using three mitochondrial genes (COI, COII, and Cytb). The long-winged (L) morph is predominant in Korean populations, and the short-winged (S) morph is very rare. Interestingly, all L morphs were infected with Wolbachia, while all Korean S morphs lacked Wolbachia, demonstrating a association between a symbiont and a phenotypic trait. A phylogenetic analysis revealed that the S morph is derived from the L morph. We propose that the S morph is associated with potential resistance to Wolbachia infection and that Wolbachia infection does not influence clonal reproduction (as is the case in other ant species).

RevDate: 2020-09-03

Zhang D, Xi Z, Li Y, et al (2020)

Toward implementation of combined incompatible and sterile insect techniques for mosquito control: Optimized chilling conditions for handling Aedes albopictus male adults prior to release.

PLoS neglected tropical diseases, 14(9):e0008561 pii:PNTD-D-20-00097.

Combined incompatible and sterile insect technique (IIT-SIT) has been considered to be an effective and safe approach to control mosquito populations. Immobilization of male adults by chilling is a crucial process required for the packing, transportation and release of the mosquitoes during the implementation of IIT-SIT for mosquito control. In this study, effects of chilling on the Aedes albopictus males with triple Wolbachia infections (HC line), a powerful weapon to fight against the wild type Ae. albopictus population via IIT-SIT, were evaluated under both laboratory and field conditions. Irradiated HC (IHC) males were exposed to 1, 5 and 10°C for 1, 2, 3, 6 and 24 h. The survival rate of the post-chilled IHC males was then monitored. Longevity of post-chilled IHC males was compared to non-chilled males under laboratory and semi-field conditions. Mating competitiveness of IHC/HC males after exposure to 5 or 10°C for 0, 3 and 24 h was then evaluated. Effects of compaction and transportation under chilled conditions on the survival rate of IHC males were also monitored. The optimal chilling conditions for handling IHC males were temperatures between 5 and 10°C for a duration of less than 3 h with no negative impacts on survival rate, longevity and mating competitiveness when compared to non-chilled males. However, the overall quality of post-chilled IHC/HC males decreased when exposed to low temperatures for 24 h. Reduced survival was observed when IHC males were stored at 5°C under a compaction height of 8 cm. Transportation with chilling temperatures fluctuating from 8 to 12°C has no negative impact on the survival of IHC males. This study identified the optimal chilling temperature and duration for the handling and transportation of Ae. albopictus IHC male adults without any detrimental effect on their survival, longevity and mating competitiveness. Further studies are required to develop drone release systems specific for chilled mosquitoes to improve release efficiency, as well as to compare the population suppression efficiency between release of post-chilled and non-chilled males in the field.

RevDate: 2020-09-03

Castillo AM, Saltonstall K, Arias CF, et al (2020)

The Microbiome of Neotropical Water Striders and Its Potential Role in Codiversification.

Insects, 11(9): pii:insects11090578.

Insects host a highly diverse microbiome, which plays a crucial role in insect life. However, the composition and diversity of microbiomes associated with Neotropical freshwater insects is virtually unknown. In addition, the extent to which diversification of this microbiome is associated with host phylogenetic divergence remains to be determined. Here, we present the first comprehensive analysis of bacterial communities associated with six closely related species of Neotropical water striders in Panama. We used comparative phylogenetic analyses to assess associations between dominant bacterial linages and phylogenetic divergence among species of water striders. We found a total of 806 16S rRNA amplicon sequence variants (ASVs), with dominant bacterial taxa belonging to the phyla Proteobacteria (76.87%) and Tenericutes (19.51%). Members of the α- (e.g., Wolbachia) and γ- (e.g., Acinetobacter, Serratia) Proteobacteria, and Mollicutes (e.g., Spiroplasma) were predominantly shared across species, suggesting the presence of a core microbiome in water striders. However, some bacterial lineages (e.g., Fructobacillus, Fluviicola and Chryseobacterium) were uniquely associated with different water strider species, likely representing a distinctive feature of each species' microbiome. These findings indicate that both host identity and environmental context are important drivers of microbiome diversity in water striders. In addition, they suggest that diversification of the microbiome is associated with diversification in water striders. Although more research is needed to establish the evolutionary consequences of host-microbiome interaction in water striders, our findings support recent work highlighting the role of bacterial community host-microbiome codiversification.

RevDate: 2020-08-28

Brattig NW, Cheke RA, R Garms (2020)

Onchocerciasis (River Blindness) - more than a Century of Research and Control.

Acta tropica pii:S0001-706X(20)30991-8 [Epub ahead of print].

This review summarises more than a century of research on onchocerciasis, also known as river blindness, and its control. River blindness is an infection caused by the tissue filaria Onchocerca volvulus affecting the skin, subcutaneous tissue and eyes and leading to blindness in a minority of infected persons. The parasite is transmitted by its intermediate hosts Simulium spp. which breed in rivers. Featured are history and milestones in onchocerciasis research and control, state-of-the-art data on the parasite, its endobacteria Wolbachia, on the vectors, previous and current prevalence of the infection, its diagnostics, the interaction between the parasite and its host, immune responses and the pathology of onchocerciasis. Detailed information is documented on the time course of control programmes in the afflicted countries in Africa and the Americas, a long road from previous programmes to current successes in control of the transmission of this infectious disease. By development, adjustment and optimization of the control measures, transmission by the vector has been interrupted in foci of countries in the Americas, in Uganda, in Sudan and elsewhere, followed by onchocerciasis eliminations. The current state and future perspectives for control, elimination and eradication within the next 20-30 years are described and discussed. This review contributes to a deeper comprehension of this disease by a tissue-dwelling filaria and it will be helpful in efforts to control and eliminate other filarial infections.

RevDate: 2020-08-28

Neupane S, Bonilla SI, Manalo AM, et al (2020)

Near-Complete Genome Sequences of a Wolbachia Strain Isolated from Diaphorina citri Kuwayama (Hemiptera: Liviidae).

Microbiology resource announcements, 9(35): pii:9/35/e00560-20.

Wolbachia strains are one of three endosymbionts associated with the insect vector of "Candidatus Liberibacter asiaticus," Diaphorina citri Kuwayama (Hemiptera: Liviidae). We report three near-complete genome sequences of samples of Wolbachia from D. citri (wDi), with sizes of 1,518,595, 1,542,468, and 1,538,523 bp.

RevDate: 2020-08-28

Adegoke A, Kumar D, Bobo C, et al (2020)

Tick-Borne Pathogens Shape the Native Microbiome Within Tick Vectors.

Microorganisms, 8(9): pii:microorganisms8091299.

Ticks are blood-feeding arthropods and transmit a variety of medically important viral, bacterial, protozoan pathogens to animals and humans. Ticks also harbor a diverse community of microbes linked to their biological processes, such as hematophagy, and hence affect vector competence. The interactions between bacterial and/or protozoan pathogens and the tick microbiome is a black-box, and therefore we tested the hypothesis that the presence of a protozoan or bacterial pathogen will alter the microbial composition within a tick. Hence, this study was designed to define the microbial composition of two tick species, Hyalomma (H.) anatolicum and Rhipicephalus (R.) microplus. We used a combination of PCR based pathogen (Anaplasma marginale and Theileria species) and symbiont (Wolbachia species) identification followed by metagenomic sequencing and comparison of the microbial communities in PCR positive and negative ticks. A total of 1786 operational taxonomic units was identified representing 25 phyla, 50 classes, and 342 genera. The phylum Proteobacteria, Firmicutes, Actinobacteriota, and Bacteroidota were the most represented bacteria group. Alpha and beta diversity were not significantly affected in the presence or absence of Theileria sp. and A. marginale as see with H. anatolicum ticks. Interestingly, bacterial communities were significantly reduced in Theileria sp. infected R. microplus ticks, while also exhibiting a significant reduction in microbial richness and evenness. Putting these observations together, we referred to the effect the presence of Theileria sp. has on R. microplus a "pathogen-induced dysbiosis". We also identify the presence of Plasmodium falciparum, the causative agent of human malaria from the microbiome of both H. anatolicum and R. microplus ticks. These findings support the presence of a "pathogen-induced dysbiosis" within the tick and further validation experiments are required to investigate how they are important in the vector competence of ticks. Understanding the mechanism of "pathogen-induced dysbiosis" on tick microbial composition may aid the discovery of intervention strategies for the control of emerging tick-borne infections.

RevDate: 2020-08-27

Johnson KN (2015)

Bacteria and antiviral immunity in insects.

Current opinion in insect science, 8:97-103.

Tripartite interactions between viruses, bacteria and hosts can have significant implications for the outcome of infections. In insects recent studies have shown that these interactions can greatly influence the transmission of vector borne disease, including transmission of dengue virus. Mosquito gut bacteria modulate arbovirus infection of the mosquito host and specific bacterial isolates have been identified that negatively impact the outcome of infection. In addition, an endosymbiotic bacterium Wolbachia, which is very common in insects, protects flies and mosquitoes from virus infection. This antiviral protection has implications for both naturally infected insects and for use in disease control. This review summarises the current state of knowledge for each of these interactions with an emphasis on natural interactions.

RevDate: 2020-08-27

Altinli M, Lequime S, Atyame C, et al (2020)

Wolbachia modulates prevalence and viral load of Culex pipiens densoviruses in natural populations.

Molecular ecology [Epub ahead of print].

The inadequacy of the standard mosquito control strategies calls for ecologically safe novel approaches, like the use of biological agents such as the endosymbiotic α-proteobacteria Wolbachia or insect-specific viruses (ISVs). Understanding the ecological interactions between these "biocontrol endosymbionts" is thus a fundamental step to achieve. Wolbachia are transmitted vertically from mother to offspring and modify their hosts' phenotypes, including reproduction (e.g. cytoplasmic incompatibility) and survival (e.g. viral interference). In nature, Culex pipiens (s.l.) mosquitoes are always found infected with genetically diverse Wolbachia called wPip that belong to five phylogenetic groups. In the recent years, ISVs have also been discovered in these mosquito species, although their interactions with Wolbachia in nature are unknown. Here, we studied the interactions between a widely prevalent ISV, the Culex pipiens densovirus (CpDV, Densovirinae), and Wolbachia in Northern-Tunisian Cx. pipiens populations. We showed an influence of different Wolbachia groups on CpDV prevalence and a general positive correlation between Wolbachia and CpDV loads. By investigating the putative relation between CpDV diversification and wPip groups in the different sites, we detected a signal linked to wPip groups in CpDV phylogeny in sites where all larvae were infected by the same wPip group. However, no such signal was detected where the wPip groups co-existed, suggesting CpDV horizontal transfers between hosts. Overall, our results provide good evidence for an ecological influence of Wolbachia on an ISV, CpDV, in natural populations and highlight the importance of integrating Wolbachia in the understanding of ISV ecology in nature.

RevDate: 2020-08-27

Sim S, Ng LC, Lindsay SW, et al (2020)

A greener vision for vector control: The example of the Singapore dengue control programme.

PLoS neglected tropical diseases, 14(8):e0008428 pii:PNTD-D-19-02097.

Vector-borne diseases are a major cause of morbidity and mortality worldwide. Aedes-borne diseases, in particular, including dengue, chikungunya, yellow fever, and Zika, are increasing at an alarming rate due to urbanisation, population movement, weak vector control programmes, and climate change. The World Health Organization calls for strengthening of vector control programmes in line with the Global Vector Control Response (GVCR) strategy, and many vector control programmes are transitioning to this new approach. The Singapore dengue control programme, situated within the country's larger vision of a clean, green, and sustainable environment for the health and well-being of its citizens, provides an excellent example of the GVCR approach in action. Since establishing vector control operations in the 1960s, the Singapore dengue control programme succeeded in reducing the dengue force of infection 10-fold by the 1990s and has maintained it at low levels ever since. Key to this success is consideration of dengue as an environmental disease, with a strong focus on source reduction and other environmental management methods as the dominant vector control strategy. The programme collaborates closely with other government ministries, as well as town councils, communities, the private sector, and academic and research institutions. Community engagement programmes encourage source reduction, and house-to-house inspections accompanied by a strong legislative framework with monetary penalties help to support compliance. Strong vector and epidemiological surveillance means that routine control activities can be heightened to specifically target dengue clusters. Despite its success, the programme continues to innovate to tackle challenges such as climate change, low herd immunity, and manpower constraints. Initiatives include development of novel vector controls such as Wolbachia-infected males and spatiotemporal models for dengue risk assessment. Lessons learnt from the Singapore programme can be applied to other settings, even those less well-resourced than Singapore, for more effective vector control.

RevDate: 2020-08-27

Hubert J, Nesvorna M, Green SJ, et al (2020)

Microbial Communities of Stored Product Mites: Variation by Species and Population.

Microbial ecology pii:10.1007/s00248-020-01581-y [Epub ahead of print].

Arthropod-associated microorganisms are important because they affect host fitness, protect hosts from pathogens, and influence the host's ability to vector pathogens. Stored product mites (Astigmata) often establish large populations in various types of food items, damaging the food by direct feeding and introducing contaminants, including their own bodies, allergen-containing feces, and associated microorganisms. Here we access the microbial structure and abundance in rearing diets, eggs, feces fraction, and mite bodies of 16 mite populations belonging to three species (Carpoglyphus lactis, Acarus siro, and Tyrophagus putrescentiae) using quantitative PCR and 16S ribosomal RNA (rRNA) gene amplicon sequencing. The mite microbiomes had a complex structure dominated by the following bacterial taxa (OTUs): (a) intracellular symbionts of the genera Cardinium and Wolbachia in the mite bodies and eggs; (b) putative gut symbionts of the genera Solitalea, Bartonella, and Sodalis abundant in mite bodies and also present in mite feces; (c) feces-associated or environmental bacteria of the genera Bacillus, Staphylococcus, and Kocuria in the diet, mite bodies, and feces. Interestingly and counterintuitively, the differences between microbial communities in various conspecific mite populations were higher than those between different mite species. To explain some of these differences, we hypothesize that the intracellular bacterial symbionts can affect microbiome composition in mite bodies, causing differences between microbial profiles. Microbial profiles differed between various sample types, such as mite eggs, bodies, and the environment (spent growth medium-SPGM). Low bacterial abundances in eggs may result in stochastic effects in parent-offspring microbial transmission, except for the intracellular symbionts. Bacteria in the rearing diet had little effect on the microbial community structure in SPGM and mite bodies. Mite fitness was positively correlated with bacterial abundance in SPGM and negatively correlated with bacterial abundances in mite bodies. Our study demonstrates critical host-microbe interactions, affecting all stages of mite growth and leading to alteration of the environmental microbiome. Correlational evidence based on absolute quantitation of bacterial 16S rRNA gene copies suggests that mite-associated microorganisms are critical for modulating important pest properties of mites by altering population growth.

RevDate: 2020-08-27

Esteban-Mendoza MV, Arcila-Quiceno V, Albarracín-Navas J, et al (2020)

Current Situation of the Presence of Dirofilaria immitis in Dogs and Humans in Bucaramanga, Colombia.

Frontiers in veterinary science, 7:488.

The cardiopulmonary dirofilariosis caused by Dirofilaria immitis, is a vector-borne infection, which can be transmitted to humans. The main hosts are both domestic and wild canids. This species mainly occurs in tropical and subtropical climates, and temperature and humidity are the main factors that favor the presence and proliferation of culicid mosquitoes as vectors of the disease. There are few reports of cardiopulmonary dirofilariosis in dogs and humans in Colombia, a region with favorable climatic conditions which favors the presence of mosquitoes that act as vectors of the disease. Therefore, this study aimed to examine its current prevalence in dogs and the risk of human exposure to the disease in Bucaramanga, one of the most populated areas in Colombia located at the center of the country. Furthermore, its demographic and environmental characteristics could be useful as a study model for other similar locations and neighboring countries. Serum samples from 351 dogs and 506 humans from the Bucaramanga Metropolitan area were analyzed. All dog samples were analyzed by Knott's technique and tested with a commercial immunochromatographic to detect the presence of circulating antigens of D. immitis. Human samples were analyzed using a non-commercial ELISA test kit to detect IgG against the somatic antigens of adult D. immitis and Wolbachia. Positive results were further confirmed using western blot analysis. Thirty-eight dogs tested positive with a overall prevalence of 10.82%. Of these dogs, 18 showed D. immitis microfilariae, being 5.12% of the total population. The overall seroprevalence in humans was 6.71%; seroprevalence was significantly higher in individuals aged 16-34 years-old and in women than in men. To our knowledge, this study describes seropositivity to D. immitis for the first time in a Colombian human population located in the same area as that of dogs infected with D. immitis, which represents a potential threat to public health. In humans, age and gender can be considered risk factors for exposure to D. immitis.

RevDate: 2020-08-27

Lu P, Sun Q, Fu P, et al (2020)

Wolbachia Inhibits Binding of Dengue and Zika Viruses to Mosquito Cells.

Frontiers in microbiology, 11:1750.

As traditional approaches to the control of dengue and Zika are insufficient, significant efforts have been made to develop utilization of the endosymbiotic bacterium Wolbachia to reduce the ability of mosquitoes to transmit pathogens. Although Wolbachia is known to inhibit flaviviruses in mosquitoes, including dengue virus (DENV) and Zika virus (ZIKV), it remains unclear how the endosymbiont interferes with viral replication cycle. In this study, we have carried out viral binding assays to investigate the impact of the Wolbachia strain wAlbB on the attachment of DENV serotype 2 (DENV-2) and ZIKV to Aedes aegypti Aag-2 cells. RNA interference (RNAi) was used to silence a variety of putative mosquito receptors of DENV that were differentially regulated by wAlbB in Aag-2 cells, in order to identify host factors involved in the inhibition of viral binding. Our results showed that, in addition to suppression of viral replication, Wolbachia strongly inhibited binding of both DENV-2 and ZIKV to Aag-2 cells. Moreover, the expression of two putative mosquito DENV receptors - dystroglycan and tubulin - was downregulated by wAlbB, and their knock-down resulted in the inhibition of DENV-2 binding to Aag-2 cells. These results will aid in understanding the Wolbachia-DENV interactions in mosquito and the development of novel control strategies for mosquito-borne diseases.

RevDate: 2020-08-24

Wuliandari JR, Hoffmann AA, Tantowijoyo W, et al (2020)

Frequency of kdr mutations in the voltage-sensitive sodium channel (VSSC) gene in Aedes aegypti from Yogyakarta and implications for Wolbachia-infected mosquito trials.

Parasites & vectors, 13(1):429 pii:10.1186/s13071-020-04304-x.

BACKGROUND: In the inner city of Yogyakarta, Indonesia, insecticide resistance is expected in the main dengue vector, Aedes aegypti, because of the intensive local application of pyrethroid insecticides. However, detailed information about the nature of resistance in this species is required to assist the release of Wolbachia mosquitoes in a dengue control program, so that we can ensure that insecticide resistance in the strain of Ae. aegypti being released matches that of the background population.

METHODS: High-resolution melt genotyping was used to screen for kdr mutations associated with pyrethroid resistance in the voltage-sensitive sodium channel (VSSC) gene in Ae. aegypti of some areas in the inner city of Yogyakarta.

RESULTS: The results show that the V1016G mutation predominated, with individuals homozygous for the 1016G allele at a frequency of 82.1% and the mutant allele G at a frequency of 92%. Two patterns of co-occurrence of mutations were detected in this study, homozygous individuals V1016G/S989P; and heterozygous individuals V1016G/F1534C/S989P. We found the simultaneous occurrence of kdr mutations V1016G and F1534C at all collection sites, but not within individual mosquitoes. Homozygous mutants at locus 1016 were homozygous wild-type at locus 1534 and vice versa, and heterozygous V1016G were also heterozygous for F1534C. The most common tri-locus genotype co-occurrences were homozygous mutant 1016GG and homozygous wild-type FF1534, combined with homozygous mutant 989PP (GG/FF/PP) at a frequency of 38.28%.

CONCLUSIONS: Given the relatively small differences in frequency of resistance alleles across the city area, locality variations in resistance should have minor implications for the success of Wolbachia mosquito trials being undertaken in the Yogyakarta area.

RevDate: 2020-08-22

Bykov R, Kerchev I, Demenkova M, et al (2020)

Sex-Specific Wolbachia Infection Patterns in Populations of Polygraphus proximus Blandford (Coleoptera; Curculionidae: Scolytinae).

Insects, 11(8): pii:insects11080547.

Wolbachia symbionts are maternally inherited bacteria that are widely distributed among Arthropoda hosts. Wolbachia influence their host biology in diverse ways. They may induce reproductive abnormalities, protect hosts against pathogens and parasites, or benefit hosts through metabolic provisioning. The progeny of an infected female are ordinarily infected with Wolbachia; however, Wolbachia have no future in male host progeny because they cannot transmit the symbiont to the next generation. Here, we analyze native and invasive populations of the four-eyed fir bark beetle (Polygraphus proximus) for Wolbachia prevalence and symbiont genetic diversity. This species is a dangerous pest of Siberian fir (Abies sibirica) forests. The native range of P. proximus includes the territories of the Russian Far East, Japan, Korea, and Northeast China, whereas its invasive range includes West Siberia, with further expansion westward. Surprisingly, we revealed a difference in the patterns of Wolbachia prevalence for males and females. Infection rate and Wolbachia titers were higher in females than in males. ST-533, the only haplotype of Wolbachia supergroup B, was associated with a minimum of three out of the five described mitochondrial haplotypes.

RevDate: 2020-08-22

Dally M, Lalzar M, Belausov E, et al (2020)

Cellular Localization of Two Rickettsia Symbionts in the Digestive System and within the Ovaries of the Mirid Bug, Macrolophous pygmaeus.

Insects, 11(8): pii:insects11080530.

Bacterial symbionts in arthropods are common, vary in their effects, and can dramatically influence the outcome of biological control efforts. Macrolophus pygmaeus (Heteroptera: Miridae), a key component of biological control programs, is mainly predaceous but may also display phytophagy. M. pygmaeus hosts symbiotic Wolbachia, which induce cytoplasmic incompatibility, and two Rickettsia species, R. bellii and R. limoniae, which are found in all individuals tested. To test possible involvement of the two Rickettsia species in the feeding habits of M. pygmaeus, we first showed that the microbiome of the insect is dominated by these three symbionts, and later described the distribution pattern of the two Rickettsia species in its digestive system. Although both Rickettsia species were located in certain gut bacteriocyes, in caeca and in Malpighian tubules of both sexes, each species has a unique cellular occupancy pattern and specific distribution along digestive system compartments. Infrequently, both species were found in a cell. In females, both Rickettsia species were detected in the germarium, the apical end of the ovarioles within the ovaries, but not in oocytes. Although the cause for these Rickettsia distribution patterns is yet unknown, it is likely linked to host nutrition while feeding on prey or plants.

RevDate: 2020-08-22

Ahmad NA, Endersby-Harshman NM, Mohd Mazni NR, et al (2020)

Characterization of Sodium Channel Mutations in the Dengue Vector Mosquitoes Aedesaegypti and Aedesalbopictus within the Context of Ongoing Wolbachia Releases in Kuala Lumpur, Malaysia.

Insects, 11(8): pii:insects11080529.

Specific sodium channel gene mutations confer target site resistance to pyrethroid insecticides in mosquitoes and other insects. In Aedes mosquito species, multiple mutations that contribute to resistance vary in their importance around the world. Here, we characterize voltage sensitive sodium channel (Vssc) mutations in populations of Aedesaegypti from Kuala Lumpur, Malaysia, and look at their persistence in populations affected by ongoing Wolbachia releases (a dengue control measure). We also describe a Vssc mutation in Aedesalbopictus (F1534L) found for the first time in Malaysia. We show that there are three predominant Vssc haplotypes in Aedesaegypti in this region, which all persist with regular backcrossing, thereby maintaining the original genetic composition of the populations. We identify changes in genotype frequency in closed populations of Ae. aegypti maintained for multiple generations in laboratory culture, suggesting different fitness costs associated with the genotypes, some of which may be associated with the sex of the mosquito. Following population replacement of Ae. aegypti by Wolbachia in the target area, however, we find that the Vssc mutations have persisted at pre-release levels. Mosquitoes in two genotype classes demonstrate a type I pyrethroid resistance advantage over wildtype mosquitoes when exposed to 0.25% permethrin. This resistance advantage is even more pronounced with a type II pyrethroid, deltamethrin (0.03%). The results point to the importance of these mutations in pyrethroid resistance in mosquito populations and the need for regular backcrossing with male mosquitoes from the field to maintain similarity of genetic background and population integrity during Wolbachia releases.

RevDate: 2020-08-21

Filipović I, Hapuarachchi HC, Tien WP, et al (2020)

Using spatial genetics to quantify mosquito dispersal for control programs.

BMC biology, 18(1):104 pii:10.1186/s12915-020-00841-0.

BACKGROUND: Hundreds of millions of people get a mosquito-borne disease every year and nearly one million die. Transmission of these infections is primarily tackled through the control of mosquito vectors. The accurate quantification of mosquito dispersal is critical for the design and optimization of vector control programs, yet the measurement of dispersal using traditional mark-release-recapture (MRR) methods is logistically challenging and often unrepresentative of an insect's true behavior. Using Aedes aegypti (a major arboviral vector) as a model and two study sites in Singapore, we show how mosquito dispersal can be characterized by the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors.

RESULTS: Using simple oviposition traps, we captured adult female Ae. aegypti across high-rise apartment blocks and genotyped them using genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance which results from one generation of successful breeding (effective dispersal), using the distance separating full siblings and 2nd- and 3rd-degree relatives (close kin). The estimated dispersal distance kernel was exponential (Laplacian), with a mean dispersal distance (and dispersal kernel spread σ) of 45.2 m (95% CI 39.7-51.3 m), and 10% probability of a dispersal > 100 m (95% CI 92-117 m). Our genetically derived estimates matched the parametrized dispersal kernels from previous MRR experiments. If few close kin are captured, a conventional genetic isolation-by-distance analysis can be used, as it can produce σ estimates congruent with the close-kin method if effective population density is accurately estimated. Genetic patch size, estimated by spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel "tail" that influences, for example, the critical radii of release zones and the speed of Wolbachia spread in mosquito replacement programs.

CONCLUSIONS: We demonstrate that spatial genetics can provide a robust characterization of mosquito dispersal. With the decreasing cost of next-generation sequencing, the production of spatial genetic data is increasingly accessible. Given the challenges of conventional MRR methods, and the importance of quantified dispersal in operational vector control decisions, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.

RevDate: 2020-08-19

Shropshire JD, Kalra M, SR Bordenstein (2020)

Evolution-guided mutagenesis of the cytoplasmic incompatibility proteins: Identifying CifA's complex functional repertoire and new essential regions in CifB.

PLoS pathogens, 16(8):e1008794 pii:PPATHOGENS-D-20-00986 [Epub ahead of print].

Wolbachia are the world's most common, maternally-inherited, arthropod endosymbionts. Their worldwide distribution is due, in part, to a selfish drive system termed cytoplasmic incompatibility (CI) that confers a relative fitness advantage to females that transmit Wolbachia to their offspring. CI results in embryonic death when infected males mate with uninfected females but not infected females. Under the Two-by-One genetic model of CI, males expressing the two phage WO proteins CifA and CifB cause CI, and females expressing CifA rescue CI. While each protein is predicted to harbor three functional domains, there is no knowledge on how sites across these Cif domains, rather than in any one particular domain, contribute to CI and rescue. Here, we use evolution-guided, substitution mutagenesis of conserved amino acids across the Cif proteins, coupled with transgenic expression in uninfected Drosophila melanogaster, to determine the functional impacts of conserved residues evolving mostly under purifying selection. We report that amino acids in CifA's N-terminal unannotated region and annotated catalase-related domain are important for both complete CI and rescue, whereas C-terminal residues in CifA's putative domain of unknown function are solely important for CI. Moreover, conserved CifB amino acids in the predicted nucleases, peptidase, and unannotated regions are essential for CI. Taken together, these findings indicate that (i) all CifA amino acids determined to be crucial in rescue are correspondingly crucial in CI, (ii) an additional set of CifA amino acids are uniquely important in CI, and (iii) CifB amino acids across the protein, rather than in one particular domain, are all crucial for CI. We discuss how these findings advance an expanded view of Cif protein evolution and function, inform the mechanistic and biochemical bases of Cif-induced CI/rescue, and continue to substantiate the Two-by-One genetic model of CI.

RevDate: 2020-08-19

Seabourn P, Spafford H, Yoneishi N, et al (2020)

The Aedes albopictus (Diptera: Culicidae) microbiome varies spatially and with Ascogregarine infection.

PLoS neglected tropical diseases, 14(8):e0008615 pii:PNTD-D-19-01818.

The mosquito microbiome alters the physiological traits of medically important mosquitoes, which can scale to impact how mosquito populations sustain disease transmission. The mosquito microbiome varies significantly within individual mosquitoes and among populations, however the ecological and environmental factors that contribute to this variation are poorly understood. To further understand the factors that influence variation and diversity of the mosquito microbiome, we conducted a survey of the bacterial microbiome in the medically important mosquito, Aedes albopictus, on the high Pacific island of Maui, Hawai'i. We detected three bacterial Phyla and twelve bacterial families: Proteobacteria, Acitinobacteria, and Firmicutes; and Anaplasmataceae, Acetobacteraceae, Enterobacteriaceae, Burkholderiaceae, Xanthobacteraceae, Pseudomonadaceae, Streptomycetaceae, Staphylococcaceae, Xanthomonadaceae, Beijerinckiaceae, Rhizobiaceae, and Sphingomonadaceae. The Ae. albopictus bacterial microbiota varied among geographic locations, but temperature and rainfall were uncorrelated with this spatial variation. Infection status with an ampicomplexan pathosymbiont Ascogregarina taiwanensis was significantly associated with the composition of the Ae. albopictus bacteriome. The bacteriomes of mosquitoes with an A. taiwanensis infection were more likely to include several bacterial symbionts, including the most abundant lineage of Wolbachia sp. Other symbionts like Asaia sp. and several Enterobacteriaceae lineages were less prevalent in A. taiwanensis-infected mosquitoes. This highlights the possibility that inter- and intra-domain interactions may structure the Ae. albopictus microbiome.

RevDate: 2020-08-17

Indriani C, Tantowijoyo W, Rancès E, et al (2020)

Reduced dengue incidence following deployments of Wolbachia-infected Aedes aegypti in Yogyakarta, Indonesia: a quasi-experimental trial using controlled interrupted time series analysis.

Gates open research, 4:50.

Background:Ae. aegypti mosquitoes stably transfected with the intracellular bacterium Wolbachiapipientis (wMel strain) have been deployed for biocontrol of dengue and related arboviral diseases in multiple countries. Field releases in northern Australia have previously demonstrated near elimination of local dengue transmission from Wolbachia-treated communities, and pilot studies in Indonesia have demonstrated the feasibility and acceptability of the method. We conducted a quasi-experimental trial to evaluate the impact of scaled Wolbachia releases on dengue incidence in an endemic setting in Indonesia. Methods: In Yogyakarta City, Indonesia, following extensive community engagement, wMel Wolbachia-carrying mosquitoes were released every two weeks for 13-15 rounds over seven months in 2016-17, in a contiguous 5 km 2 area (population 65,000). A 3 km 2 area (population 34,000) on the opposite side of the city was selected a priori as an untreated control area. Passive surveillance data on notified hospitalised dengue patients was used to evaluate the epidemiological impact of Wolbachia deployments, using controlled interrupted time-series analysis. Results: Rapid and sustained introgression of wMel Wolbachia into local Ae. aegypti populations was achieved. Thirty-four dengue cases were notified from the intervention area and 53 from the control area (incidence 26 vs 79 per 100,000 person-years) during 24 months following Wolbachia deployment. This corresponded in the regression model to a 73% reduction in dengue incidence (95% confidence interval 49%,86%) associated with the Wolbachia intervention. Exploratory analysis including 6 months additional post-intervention observations showed a small strengthening of this effect (30 vs 115 per 100,000 person-years; 76% reduction in incidence, 95%CI 60%,86%). Conclusions: We demonstrate a significant reduction in dengue incidence following successful introgression of Wolbachia into local Ae. aegypti populations in an endemic setting in Indonesia. These findings are consistent with previous field trials in northern Australia, and support the effectiveness of this novel approach for dengue control.

RevDate: 2020-08-15

Martinez J, Klasson L, Welch JJ, et al (2020)

Life and death of selfish genes: comparative genomics reveals the dynamic evolution of cytoplasmic incompatibility.

Molecular biology and evolution pii:5892770 [Epub ahead of print].

Cytoplasmic incompatibility is a selfish reproductive manipulation induced by the endosymbiont Wolbachia in arthropods. In males Wolbachia modifies sperm, leading to embryonic mortality in crosses with Wolbachia-free females. In females, Wolbachia rescues the cross and allows development to proceed normally. This provides a reproductive advantage to infected females, allowing the maternally-transmitted symbiont to spread rapidly through host populations. We identified homologs of the genes underlying this phenotype, cifA and cifB, in 52 of 71 new and published Wolbachia genomes sequences. They are strongly associated with cytoplasmic incompatibility. There are up to seven copies of the genes in each genome, and phylogenetic analysis shows that Wolbachia frequently acquires new copies due to pervasive horizontal transfer between strains. In many cases the genes have subsequently acquired loss-of-function mutations to become pseudogenes. As predicted by theory, this tends to occur first in cifB, whose sole function is to modify sperm, and then in cifA, which is required to rescue the cross in females. Although cif genes recombine, recombination is largely restricted to closely related homologs. This is predicted under a model of coevolution between sperm modification and embryonic rescue, where recombination between distantly related pairs of genes would create a self-incompatible strain. Together, these patterns of gene gain, loss and recombination support evolutionary models of cytoplasmic incompatibility.

RevDate: 2020-08-15

Straub TJ, Shaw WR, Marcenac P, et al (2020)

The Anopheles coluzzii microbiome and its interaction with the intracellular parasite Wolbachia.

Scientific reports, 10(1):13847 pii:10.1038/s41598-020-70745-0.

Wolbachia, an endosymbiotic alpha-proteobacterium commonly found in insects, can inhibit the transmission of human pathogens by mosquitoes. Biocontrol programs are underway using Aedes aegypti mosquitoes trans-infected with a non-natural Wolbachia strain to reduce dengue virus transmission. Less is known about the impact of Wolbachia on the biology and vectorial capacity of Anopheles mosquitoes, the vectors of malaria parasites. A naturally occurring strain of Wolbachia, wAnga, infects populations of the major malaria vectors Anopheles gambiae and Anopheles coluzzii in Burkina Faso. Previous studies found wAnga infection was negatively correlated with Plasmodium infection in the mosquito and wAnga influenced mosquito egg-laying behavior. Here, we investigate wAnga in natural populations of An. coluzzii and its interactions with other resident microbiota using targeted 16S sequencing. Though we find no major differences in microbiota composition associated with wAnga infection, we do find several taxa that correlate with the presence or absence of wAnga in female mosquitoes following oviposition, with the caveat that we could not rule out batch effects due to the unanticipated impact of wAnga on oviposition timing. These data suggest wAnga may influence or interact with the Anopheles microbiota, which may contribute to the impact of wAnga on Anopheles biology and vectorial capacity.

RevDate: 2020-08-14

Ferguson KB, Kursch-Metz T, Verhulst EC, et al (2020)

Hybrid Genome Assembly and Evidence-Based Annotation of the Egg Parasitoid and Biological Control Agent Trichogramma brassicae.

G3 (Bethesda, Md.) pii:g3.120.401344 [Epub ahead of print].

Trichogramma brassicae (Bezdenko) are egg parasitoids that are used throughout the world as biological control agents and in laboratories as model species. Despite this ubiquity, few genetic resources exist beyond COI, ITS2, and RAPD markers. Aided by a Wolbachia infection, a wild-caught strain from Germany was reared for low heterozygosity and sequenced in a hybrid de novo strategy, after which several assembling strategies were evaluated. The best assembly, derived from a DBG2OLC-based pipeline, yielded a genome of 235 Mbp made up of 1,572 contigs with an N50 of 556,663 bp. Following a rigorous ab initio-, homology-, and evidence-based annotation, 16,905 genes were annotated and functionally described. As an example of the utility of the genome, a simple ortholog cluster analysis was performed with sister species T. pretiosum, revealing over 6000 shared clusters and under 400 clusters unique to each species. The genome and transcriptome presented here provides an essential resource for comparative genomics of the commercially relevant genus Trichogramma, but also for research into molecular evolution, ecology, and breeding of T. brassicae.

RevDate: 2020-08-13

N Miyata M, Nomura M, D Kageyama (2020)

Wolbachia have made it twice: Hybrid introgression between two sister species of Eurema butterflies.

Ecology and evolution, 10(15):8323-8330 pii:ECE36539.

Wolbachia, cytoplasmically inherited endosymbionts of arthropods, are known to hijack their host reproduction in various ways to increase their own vertical transmission. This may lead to the selective sweep of associated mitochondria, which can have a large impact on the evolution of mitochondrial lineages. In Japan, two different Wolbacahia strains (wCI and wFem) are found in two sister species of pierid butterflies, Eurema mandarina and Eurema hecabe. In both species, females infected with wCI (C females) produce offspring with a nearly 1:1 sex ratio, while females infected with both wCI and wFem (CF females) produce all-female offspring. Previous studies have suggested the historical occurrence of hybrid introgression in C individuals between the two species. Furthermore, hybrid introgression in CF individuals is suggested by the distinct mitochondrial lineages between C females and CF females of E. mandarina. In this study, we performed phylogenetic analyses based on nuclear DNA and mitochondrial DNA markers of E. hecabe with previously published data on E. mandarina. We found that the nuclear DNA of this species significantly diverged from that of E. mandarina. By contrast, mitochondrial DNA haplotypes comprised two clades, mostly reflecting Wolbachia infection status rather than the individual species. Collectively, our results support the previously suggested occurrence of two independent historical events wherein the cytoplasms of CF females and C females moved between E. hecabe and E. mandarina through hybrid introgression.

RevDate: 2020-08-13

Wong ML, Liew JWK, Wong WK, et al (2020)

Natural Wolbachia infection in field-collected Anopheles and other mosquito species from Malaysia.

Parasites & vectors, 13(1):414 pii:10.1186/s13071-020-04277-x.

BACKGROUND: The endosymbiont bacterium Wolbachia is maternally inherited and naturally infects some filarial nematodes and a diverse range of arthropods, including mosquito vectors responsible for disease transmission in humans. Previously, it has been found infecting most mosquito species but absent in Anopheles and Aedes aegypti. However, recently these two mosquito species were found to be naturally infected with Wolbachia. We report here the extent of Wolbachia infections in field-collected mosquitoes from Malaysia based on PCR amplification of the Wolbachia wsp and 16S rRNA genes.

METHODS: The prevalence of Wolbachia in Culicinae mosquitoes was assessed via PCR with wsp primers. For some of the mosquitoes, in which the wsp primers failed to amplify a product, Wolbachia screening was performed using nested PCR targeting the 16S rRNA gene. Wolbachia sequences were aligned using Geneious 9.1.6 software, analyzed with BLAST, and the most similar sequences were downloaded. Phylogenetic analyses were carried out with MEGA 7.0 software. Graphs were drawn with GraphPad Prism 8.0 software.

RESULTS: A total of 217 adult mosquitoes representing 26 mosquito species were screened. Of these, infections with Wolbachia were detected in 4 and 15 mosquito species using wsp and 16S rRNA primers, respectively. To our knowledge, this is the first time Wolbachia was detected using 16S rRNA gene amplification, in some Anopheles species (some infected with Plasmodium), Culex sinensis, Culex vishnui, Culex pseudovishnui, Mansonia bonneae and Mansonia annulifera. Phylogenetic analysis based on wsp revealed Wolbachia from most of the mosquitoes belonged to Wolbachia Supergroup B. Based on 16S rRNA phylogenetic analysis, the Wolbachia strain from Anopheles mosquitoes were more closely related to Wolbachia infecting Anopheles from Africa than from Myanmar.

CONCLUSIONS: Wolbachia was found infecting Anopheles and other important disease vectors such as Mansonia. Since Wolbachia can affect its host by reducing the life span and provide resistance to pathogen infection, several studies have suggested it as a potential innovative tool for vector/vector-borne disease control. Therefore, it is important to carry out further studies on natural Wolbachia infection in vector mosquitoes' populations as well as their long-term effects in new hosts and pathogen suppression.

RevDate: 2020-08-13

Sucupira PHF, Ferreira ÁGA, Leite THJF, et al (2020)

The RNAi Pathway Is Important to Control Mayaro Virus Infection in Aedes aegypti but not for Wolbachia-Mediated Protection.

Viruses, 12(8): pii:v12080871.

Mayaro virus (MAYV), a sylvatic arbovirus belonging to the Togaviridae family and Alphavirus genus, is responsible for an increasing number of outbreaks in several countries of Central and South America. Despite Haemagogus janthinomys being identified as the main vector of MAYV, laboratory studies have already demonstrated the competence of Aedes aegypti to transmit MAYV. It has also been demonstrated that the WolbachiawMel strain is able to impair the replication and transmission of MAYV in Ae. aegypti. In Ae. aegypti, the small interfering RNA (siRNA) pathway is an important antiviral mechanism; however, it remains unclear whether siRNA pathway acts against MAYV infection in Ae. aegypti. The main objective of this study was to determine the contribution of the siRNA pathway in the control of MAYV infection. Thus, we silenced the expression of AGO2, an essential component of the siRNA pathway, by injecting dsRNA-targeting AGO2 (dsAGO2). Our results showed that AGO2 is required to control MAYV replication upon oral infection in Wolbachia-free Ae. aegypti. On the other hand, we found that Wolbachia-induced resistance to MAYV in Ae. aegypti is independent of the siRNA pathway. Our study brought new information regarding the mechanism of viral protection, as well as on Wolbachia mediated interference.

RevDate: 2020-08-13

Shi Y, J Yu (2020)

Wolbachia infection enhancing and decaying domains in mosquito population based on discrete models.

Journal of biological dynamics, 14(1):679-695.

In this article, we formulate and study a discrete equation model depicting the pattern of Wolbachia infection in a mosquito population. A domain in [Formula: see text] is called a Wolbachia infection enhancing (or decaying) domain if in which the Wolbachia infection frequency of the next generation is always bigger (or smaller) than that of the current generation. We first give a complete analysis of the equivalent Wolbachia infection frequency curves. And then we clearly characterize the Wolbachia infection enhancing domain and decaying domain for all of the parameters, respectively. Finally, some numerical examples are also provided to illustrate our theoretical results.

RevDate: 2020-08-11

Curran DM, Grote A, Nursimulu N, et al (2020)

Modeling the metabolic interplay between a parasitic worm and its bacterial endosymbiont allows the identification of novel drug targets.

eLife, 9: pii:51850.

The filarial nematode Brugia malayi represents a leading cause of disability in the developing world, causing lymphatic filariasis in nearly 40 million people. Currently available drugs are not well-suited to mass drug administration efforts, so new treatments are urgently required. One potential vulnerability is the endosymbiotic bacteria Wolbachia-present in many filariae-which is vital to the worm. Genome scale metabolic networks have been used to study prokaryotes and protists and have proven valuable in identifying therapeutic targets, but have only been applied to multicellular eukaryotic organisms more recently. Here, we present iDC625, the first compartmentalized metabolic model of a parasitic worm. We used this model to show how metabolic pathway usage allows the worm to adapt to different environments, and predict a set of 102 reactions essential to the survival of B. malayi. We validated three of those reactions with drug tests and demonstrated novel antifilarial properties for all three compounds.

RevDate: 2020-08-10

Duan R, Xu H, Gao S, et al (2020)

Effects of Different Hosts on Bacterial Communities of Parasitic Wasp Nasonia vitripennis.

Frontiers in microbiology, 11:1435.

Parasitism is a special interspecific relationship in insects. Unlike most other ectoparasites, Nasonia vitripennis spend most of its life cycle (egg, larvae, pupae, and early adult stage) inside the pupae of flies, which is covered with hard puparium. Microbes play important roles in host development and help insect hosts to adapt to various environments. How the microbes of parasitic wasp respond to different fly hosts living in such close relationships motivated this investigation. In this study, we used N. vitripennis and three different fly pupa hosts (Lucilia sericata, Sarcophaga marshalli, and Musca domestica) to address this question, as well as to illustrate the potential transfer of bacteria through the trophic food chains. We found that N. vitripennis from different fly pupa hosts showed distinct microbiota, which means that the different fly hosts could affect the bacterial communities of their parasitic wasps. Some bacteria showed potential horizontal transfer through the trophic food chains, from the food through the fly to the parasitic wasp. We also found that the heritable endosymbiont Wolbachia could transferred from the fly host to the parasite and correlated with the bacterial communities of the corresponding parasitic wasps. Our findings provide new insight to the microbial interactions between parasite and host.

RevDate: 2020-08-09

Thongprem P, Davison HR, Thompson DJ, et al (2020)

Incidence and Diversity of Torix Rickettsia-Odonata Symbioses.

Microbial ecology pii:10.1007/s00248-020-01568-9 [Epub ahead of print].

Heritable microbes are an important component of invertebrate biology, acting both as beneficial symbionts and reproductive parasites. Whilst most previous research has focussed on the 'Wolbachia pandemic', recent work has emphasised the importance of other microbial symbionts. In this study, we present a survey of odonates (dragonflies and damselflies) for torix group Rickettsia, following previous research indicating that this clade can be common in other aquatic insect groups. PCR assays were used to screen a broad range of odonates from two continents and revealed 8 of 76 species tested were infected with Rickettsia. We then conducted further deeper screening of UK representatives of the Coenagrionidae damselfly family, revealing 6 of 8 UK coenagrionid species to be positive for torix Rickettsia. Analysis of Rickettsia gene sequences supported multiple establishments of symbiosis in the group. Some strains were shared between UK coenagrionid species that shared mtDNA barcodes, indicating a likely route for mitochondrial introgression between sister species. There was also evidence of coinfecting Rickettsia strains in two species. FISH analysis indicated Rickettsia were observed in the ovarioles, consistent with heritable symbiosis. We conclude that torix Rickettsia represent an important associate of odonates, being found in a broad range of species from both Europe and South America. There is evidence that coinfection can occur, vertical transmission is likely, and that symbiont movement following hybridisation may underpin the lack of 'barcoding gap' between well-established species pairs in the genus. Future work should establish the biological significance of the symbioses observed.

RevDate: 2020-08-08

Liang X, Liu J, Bian G, et al (2020)

Wolbachia Inter-Strain Competition and Inhibition of Expression of Cytoplasmic Incompatibility in Mosquito.

Frontiers in microbiology, 11:1638.

Successful field trials have been reported as part of the effort to develop the maternally transmitted endosymbiontic bacteria Wolbachia as an intervention agent for controlling mosquito vectors and their transmitted diseases. In order to further improve this novel intervention, artificially transinfected mosquitoes must be optimized to display maximum pathogen blocking, the desired cytoplasmic incompatibility (CI) pattern, and the lowest possible fitness cost. Achieving such optimization, however, requires a better understanding of the interactions between the host and various Wolbabachia strains and their combinations. Here, we transferred the Wolbachia wMel strain by embryonic microinjection into Aedes albopictus, resulting in the successful establishment of a transinfected line, HM (wAlbAwAlbBwMel), with a triple-strain infection comprising wMel, wAlbA, and wAlbB. Surprisingly, no CI was induced when the triply infected males were crossed with the wild-type GUA females or with another triply infected HC females carrying wPip, wAlbA, and wAlbB, but specific removal of wAlbA from the HM (wAlbAwAlbBwMel) line resulted in the expression of CI after crosses with lines infected by either one, two, or three strains of Wolbachia. The transinfected line showed perfect maternal transmission of the triple infection, with fluctuating egg hatch rates that improved to normal levels after repeated outcrosses with GUA line. Strain-specific qPCR assays showed that wMel and wAlbB were present at the highest densities in the ovaries and midguts, respectively, of the HM (wAlbAwAlbBwMel) mosquitoes. These finding suggest that introducing a novel strain of Wolbachia into a Wolbachia-infected host may result in complicated interactions between Wolbachia and the host and between the various Wolbachia strains, with competition likely to occur between strains in the same supergroup.

RevDate: 2020-08-07

Dew RM, McFrederick QS, SM Rehan (2020)

Diverse Diets with Consistent Core Microbiome in Wild Bee Pollen Provisions.

Insects, 11(8): pii:insects11080499.

Bees collect pollen from flowers for their offspring, and by doing so contribute critical pollination services for our crops and ecosystems. Unlike many managed bee species, wild bees are thought to obtain much of their microbiome from the environment. However, we know surprisingly little about what plant species bees visit and the microbes associated with the collected pollen. Here, we addressed the hypothesis that the pollen and microbial components of bee diets would change across the range of the bee, by amplicon sequencing pollen provisions of a widespread small carpenter bee, Ceratina calcarata, across three populations. Ceratina calcarata was found to use a diversity of floral resources across its range, but the bacterial genera associated with pollen provisions were very consistent. Acinetobacter, Erwinia, Lactobacillus, Sodalis, Sphingomonas and Wolbachia were among the top ten bacterial genera across all sites. Ceratina calcarata uses both raspberry (Rubus) and sumac (Rhus) stems as nesting substrates, however nests within these plants showed no preference for host plant pollen. Significant correlations in plant and bacterial co-occurrence differed between sites, indicating that many of the most common bacterial genera have either regional or transitory floral associations. This range-wide study suggests microbes present in brood provisions are conserved within a bee species, rather than mediated by climate or pollen composition. Moving forward, this has important implications for how these core bacteria affect larval health and whether these functions vary across space and diet. These data increase our understanding of how pollinators interact with and adjust to their changing environment.

RevDate: 2020-08-05

Laidoudi Y, Medkour H, Levasseur A, et al (2020)

New Molecular Data on Filaria and its Wolbachia from Red Howler Monkeys (Alouatta macconnelli) in French Guiana-A Preliminary Study.

Pathogens (Basel, Switzerland), 9(8): pii:pathogens9080626.

Previous studies have reported filarial parasites of the genus Dipetalonema and Mansonella from French Guiana monkeys, based on morphological taxonomy. In this study, we screened blood samples from nine howler monkeys (Alouatta macconnelli) for the presence of filaria and Wolbachia DNA. The infection rates were 88.9% for filaria and 55.6% for wolbachiae. The molecular characterization, based on the 18S gene of filariids, revealed that A. macconnelli are infected with at least three species (Mansonella sp., Brugia sp. and an unidentified Onchocercidae species.). Since the 18S and cox1 generic primers are not very effective at resolving co-infections, we developed ITS genus-specific PCRs for Mansonella and Brugia genus. The results revealed coinfections in 75% of positives. The presence of Mansonella sp. and Brugia sp. was also confirmed by the 16S phylogenetic analysis of their associated Wolbachia. Mansonella sp., which close to the species from the subgenus Tetrapetalonema encountered in New World Monkeys, while Brugia sp. was identical to the strain circulating in French Guiana dogs. We propose a novel ITS1Brugia genus-specific qPCR. We applied it to screen for Brugia infection in howler monkeys and 66.7% were found to be positive. Our finding highlights the need for further studies to clarify the species diversity of neotropics monkeys by combining molecular and morphological features. The novel Brugia genus-specific qPCR assays could be an effective tool for the surveillance and characterization of this potential zoonosis.

RevDate: 2020-08-04

Huang M, L Hu (2020)

Modeling the suppression dynamics of Aedes mosquitoes with mating inhomogeneity.

Journal of biological dynamics, 14(1):656-678.

A novel strategy for controlling mosquito-borne diseases, such as dengue, malaria and Zika, involves releases of Wolbachia-infected mosquitoes as Wolbachia cause early embryo death when an infected male mates with an uninfected female. In this work, we introduce a delay differential equation model with mating inhomogeneity to discuss mosquito population suppression based on Wolbachia. Our analyses show that the wild mosquitoes could be eliminated if either the adult mortality rate exceeds the threshold [Formula: see text] or the release amount exceeds the threshold [Formula: see text] uniformly. We also present the nonlinear dependence of [Formula: see text] and [Formula: see text] on the parameters, respectively, as well as the effect of pesticide spraying on wild mosquitoes. Our simulations suggest that the releasing should be started at least 5 weeks before the peak dengue season, taking into account both the release amount and the suppression speed.

RevDate: 2020-08-04

Ashour DS, AA Othman (2020)

Parasite-bacteria interrelationship.

Parasitology research pii:10.1007/s00436-020-06804-2 [Epub ahead of print].

Parasites and bacteria have co-evolved with humankind, and they interact all the time in a myriad of ways. For example, some bacterial infections result from parasite-dwelling bacteria as in the case of Salmonella infection during schistosomiasis. Other bacteria synergize with parasites in the evolution of human disease as in the case of the interplay between Wolbachia endosymbiont bacteria and filarial nematodes as well as the interaction between Gram-negative bacteria and Schistosoma haematobium in the pathogenesis of urinary bladder cancer. Moreover, secondary bacterial infections may complicate several parasitic diseases such as visceral leishmaniasis and malaria, due to immunosuppression of the host during parasitic infections. Also, bacteria may colonize the parasitic lesions; for example, hydatid cysts and skin lesions of ectoparasites. Remarkably, some parasitic helminths and arthropods exhibit antibacterial activity usually by the release of specific antimicrobial products. Lastly, some parasite-bacteria interactions are induced as when using probiotic bacteria to modulate the outcome of a variety of parasitic infections. In sum, parasite-bacteria interactions involve intricate processes that never cease to intrigue the researchers. However, understanding and exploiting these interactions could have prophylactic and curative potential for infections by both types of pathogens.

RevDate: 2020-08-03

Wang Z, Li H, Zhou X, et al (2020)

Comparative characterization of microbiota between the sibling species of tea geometrid moth Ectropis obliqua Prout and E. grisescens Warren.

Bulletin of entomological research pii:S0007485320000164 [Epub ahead of print].

For a wide range of insect species, the microbiota has potential roles in determining host developmental programme, immunity and reproductive biology. The tea geometrid moths Ectropis obliqua and E. grisescens are two closely related species that mainly feed on tea leaves. Although they can mate, infertile hybrids are produced. Therefore, these species provide a pair of model species for studying the molecular mechanisms of microbiotal involvement in host reproductive biology. In this study, we first identified and compared the compositions of microbiota between these sibling species, revealing higher microbiotal diversity for E. grisescens. The microbiota of E. obliqua mainly comprised the phyla Firmicutes, Proteobacteria and Cyanobacteria, whereas that of E. grisescens was dominated by Proteobacteria, Actinobacteria and Firmicutes. At the genus level, the dominant microbiota of E. grisescens included Wolbachia, Enterobacter and Pseudomonas and that of E. obliqua included Melissococcus, Staphylococcus and Enterobacter. Furthermore, we verified the rate of Wolbachia to infect 80 samples from eight different geographical populations, and the results supported that only E. grisescens harboured Wolbachia. Taken together, our findings indicate significantly different microbiotal compositions for E. obliqua and E. grisescens, with Wolbachia possibly being a curial factor influencing the reproductive isolation of these species. This study provides new insight into the mechanisms by which endosymbiotic bacteria, particularly Wolbachia, interact with sibling species.

RevDate: 2020-08-02

Zheng X (2020)

Unveiling mosquito cryptic species and their reproductive isolation.

Insect molecular biology [Epub ahead of print].

Mosquitoes are major vectors of many infectious pathogens or parasites. Understanding cryptic species and the speciation of disease vectors has important implications for vector management, evolution, and host-pathogen and/or host-parasite interactions. Currently, mosquito cryptic species have been reported in many studies, most of which focus on the reproductive isolation of cryptic species and mainly on Anopheles gambiae sensu lato complex. Emerging species within the primary malaria vector Anopheles gambiae show different ecological preferences and significant prezygotic reproductive isolation, while Aedes mariae and Aedes zammitii show postmating reproductive isolation. However, data reporting the reproductive isolation in Culex and Aedes albopictus mosquito cryptic species is absent. The lack of systematic studies leaves many questions open, such as whether cryptic species are more common in particular habitats, latitudes, or taxonomic groups; what mosquito cryptic species evolutionary processes bring about reproductive isolation in the absence of morphological differentiation? How does Wolbachia infection affect in mosquitoes' reproductive isolation? In this review, we provide a summary of recent advances in the discovery and identification of sibling or cryptic species within mosquito genera.

RevDate: 2020-08-01

Takamatsu T, Arai H, Abe N, et al (2020)

Coexistence of Two Male-Killers and Their Impact on the Development of Oriental Tea Tortrix Homona magnanima.

Microbial ecology pii:10.1007/s00248-020-01566-x [Epub ahead of print].

Male-killing, the death of male offspring induced by maternally transmitted microbes, is classified as early, or late, male-killing. The primary advantage afforded by early male-killing, which typically occurs during embryogenesis, is the reallocation of resources to females, that would have otherwise been consumed by males. Meanwhile, the key advantage of late male-killing, which typically occurs during late larval development, is the maximized potential for horizontal transmission. To date, no studies have reported on the associated developmental and physiological effects of host coinfection with early and late male-killers, which may have a significant impact on the population dynamics of the male-killers. Here we used a lepidopteran tea pest Homona magnanima as a model, which is a unique system wherein an early male-killer (a Spiroplasma bacterium) and a late male-killer (an RNA virus) can coexist in nature. An artificially established matriline, coinfected with both Spiroplasma and RNA virus, exhibited embryonic death (early male-killing) as seen in the host line singly infected with Spiroplasma. Moreover, the coinfected line also exhibited developmental retardation and low pupal weight similar to the host line singly infected with the RNA virus. A series of field surveys revealed that Spiroplasma-RNA virus coinfection occurs in nature at a low frequency. Hence, although the two male-killers are capable of coexisting within the H. magnanima population independently, high associated fitness cost appears to limit the prevalence of male-killer coinfection in the field host population.

RevDate: 2020-07-31

Ford SA, Albert I, Allen SL, et al (2020)

Artificial Selection Finds New Hypotheses for the Mechanism of Wolbachia-Mediated Dengue Blocking in Mosquitoes.

Frontiers in microbiology, 11:1456.

Wolbachia is an intracellular bacterium that blocks virus replication in insects and has been introduced into the mosquito, Aedes aegypti for the biocontrol of arboviruses including dengue, Zika, and chikungunya. Despite ongoing research, the mechanism of Wolbachia-mediated virus blocking remains unclear. We recently used experimental evolution to reveal that Wolbachia-mediated dengue blocking could be selected upon in the A. aegypti host and showed evidence that strong levels of blocking could be maintained by natural selection. In this study, we investigate the genetic variation associated with blocking and use these analyses to generate testable hypotheses surrounding the mechanism of Wolbachia-mediated dengue blocking. From our results, we hypothesize that Wolbachia may block virus replication by increasing the regeneration rate of mosquito cells via the Notch signaling pathway. We also propose that Wolbachia modulates the host's transcriptional pausing pathway either to prime the host's anti-viral response or to directly inhibit viral replication.

RevDate: 2020-07-31

Wöger R, Wöger R, M Nuss (2020)

Spatial and temporal sex ratio bias and Wolbachia-infection in New Zealand Crambidae (Lepidoptera: Pyraloidea).

Biodiversity data journal, 8:e52621 pii:52621.

The New Zealand fauna of snout moths (Pyraloidea) predominantly consists of endemic species. During 2017 and 2018, 56 species of Pyraloidea in 1,749 individuals were collected at 14 localities. All species were screened for Wolbachia-infection, with specimens of eight species (14%) being positive, of which six species belong to Scopariinae. This is the first record of Wolbachia-infection amongst New Zealand Lepidoptera. The most common pyraloid species, Eudonia submarginalis and Orocrambus flexuosellus, were analysed for a larger set of individuals looking for sex ratio and Wolbachia-infection. There is a sex ratio bias towards females in both species, but it varies in space and time. Wolbachia is found in all populations of E. submarginalis with 10-80% of the tested individuals being positive, depending on locality. No Wolbachia-infection has been found in O. flexuosellus. Thus, sex ratio bias might be linked to Wolbachia-infection in E. submarginalis, but not in O. flexuosellus.

RevDate: 2020-07-29

Fraser JE, O'Donnell TB, Duyvestyn JM, et al (2020)

Novel phenotype of Wolbachia strain wPip in Aedes aegypti challenges assumptions on mechanisms of Wolbachia-mediated dengue virus inhibition.

PLoS pathogens, 16(7):e1008410 pii:PPATHOGENS-D-20-00256 [Epub ahead of print].

The bacterial endosymbiont Wolbachia is a biocontrol tool that inhibits the ability of the Aedes aegypti mosquito to transmit positive-sense RNA viruses such as dengue and Zika. Growing evidence indicates that when Wolbachia strains wMel or wAlbB are introduced into local mosquito populations, human dengue incidence is reduced. Despite the success of this novel intervention, we still do not fully understand how Wolbachia protects mosquitoes from viral infection. Here, we demonstrate that the Wolbachia strain wPip does not inhibit virus infection in Ae. aegypti. We have leveraged this novel finding, and a panel of Ae. aegypti lines carrying virus-inhibitory (wMel and wAlbB) and non-inhibitory (wPip) strains in a common genetic background, to rigorously test a number of hypotheses about the mechanism of Wolbachia-mediated virus inhibition. We demonstrate that, contrary to previous suggestions, there is no association between a strain's ability to inhibit dengue infection in the mosquito and either its typical density in the midgut or salivary glands, or the degree to which it elevates innate immune response pathways in the mosquito. These findings, and the experimental platform provided by this panel of genetically comparable mosquito lines, clear the way for future investigations to define how Wolbachia prevents Ae. aegypti from transmitting viruses.

RevDate: 2020-07-29

Chen H, Zhang M, M Hochstrasser (2020)

The Biochemistry of Cytoplasmic Incompatibility Caused by Endosymbiotic Bacteria.

Genes, 11(8): pii:genes11080852.

Many species of arthropods carry maternally inherited bacterial endosymbionts that can influence host sexual reproduction to benefit the bacterium. The most well-known of such reproductive parasites is Wolbachia pipientis. Wolbachia are obligate intracellular α-proteobacteria found in nearly half of all arthropod species. This success has been attributed in part to their ability to manipulate host reproduction to favor infected females. Cytoplasmic incompatibility (CI), a phenomenon wherein Wolbachia infection renders males sterile when they mate with uninfected females, but not infected females (the rescue mating), appears to be the most common. CI provides a reproductive advantage to infected females in the presence of a threshold level of infected males. The molecular mechanisms of CI and other reproductive manipulations, such as male killing, parthenogenesis, and feminization, have remained mysterious for many decades. It had been proposed by Werren more than two decades ago that CI is caused by a Wolbachia-mediated sperm modification and that rescue is achieved by a Wolbachia-encoded rescue factor in the infected egg. In the past few years, new research has highlighted a set of syntenic Wolbachia gene pairs encoding CI-inducing factors (Cifs) as the key players for the induction of CI and its rescue. Within each Cif pair, the protein encoded by the upstream gene is denoted A and the downstream gene B. To date, two types of Cifs have been characterized based on the enzymatic activity identified in the B protein of each protein pair; one type encodes a deubiquitylase (thus named CI-inducing deubiquitylase or cid), and a second type encodes a nuclease (named CI-inducing nuclease or cin). The CidA and CinA proteins bind tightly and specifically to their respective CidB and CinB partners. In transgenic Drosophila melanogaster, the expression of either the Cid or Cin protein pair in the male germline induces CI and the expression of the cognate A protein in females is sufficient for rescue. With the identity of the Wolbachia CI induction and rescue factors now known, research in the field has turned to directed studies on the molecular mechanisms of CI, which we review here.

RevDate: 2020-07-28

Chung M, Basting PJ, Patkus RS, et al (2020)

A Meta-Analysis of Wolbachia Transcriptomics Reveals a Stage-Specific Wolbachia Transcriptional Response Shared Across Different Hosts.

G3 (Bethesda, Md.) pii:g3.120.401534 [Epub ahead of print].

Wolbachia is a genus containing obligate, intracellular endosymbionts with arthropod and nematode hosts. Numerous studies have identified differentially expressed transcripts in Wolbachia endosymbionts that potentially inform the biological interplay between these endosymbionts and their hosts, albeit with discordant results. Here, we re-analyze all previously published major Wolbachia RNA-Seq transcriptomics data sets using a single workflow consisting of the most up-to-date algorithms and techniques, with the aim of identifying trends or patterns in the pan-Wolbachia transcriptional response. We find that data from one of the early studies in filarial nematodes did not allow for robust conclusions about Wolbachia differential expression with these methods, suggesting the original interpretations should be reconsidered. Across datasets analyzed with this unified workflow, there is a general lack of global gene regulation with the exception of a weak transcriptional response resulting in the upregulation of ribosomal proteins in early larval stages. This weak response is observed across diverse Wolbachia strains from both nematode and insect hosts suggesting a potential pan-Wolbachia transcriptional response during host development that diverged more than 700 million years ago.

RevDate: 2020-07-28
CmpDate: 2020-07-28

Wang LX, Shi PJ, HG Zhang (2019)

Bifurcation analysis of a wild and sterile mosquito model.

Mathematical biosciences and engineering : MBE, 16(5):3215-3234.

The bifurcation of an ordinary differential equation model describing interaction of the wild and the released sterile mosquitoes is analyzed. It is shown that the model undergoes a sequence of bifurcations including saddle-node bifurcation, supercritical Hopf bifurcation, subcritical Hopf bifurcation, homoclinic bifurcation and Bogdanov-Takens bifurcation. We also find that the model displays monostable, bistable or tristable dynamics. This analysis suggests that the densities of the initial wild mosquitoes and the released sterile ones determine the asymptotic states of both populations. This study may give an insight into the estimation number of the released sterile mosquitoes.

RevDate: 2020-07-26

Taghikhani R, Sharomi O, AB Gumel (2020)

Dynamics of a two-sex model for the population ecology of dengue mosquitoes in the presence of Wolbachia.

Mathematical biosciences pii:S0025-5564(20)30099-7 [Epub ahead of print].

The release of Wolbachia-infected mosquitoes into the population of wild mosquitoes is one of the promising biological control method for combating the population abundance of mosquitoes that cause deadly diseases, such as dengue. In this study, a new two-sex mathematical model for the population ecology of dengue mosquitoes and disease is designed and used to assess the population-level impact of the periodic release of Wolbachia-infected mosquitoes. Rigorous analysis of the model, which incorporates many of the lifecycle features of dengue disease and the cytoplasmic incompatibility property of Wolbachia bacterium in mosquitoes, reveal that the disease-free equilibrium of the model is locally-asymptotically stable whenever a certain epidemiological threshold, known as the reproduction number of the model (denoted by R0W), is less than unity. The model is shown, using center manifold theory, to undergo the phenomenon of backward bifurcation at R0W=1. The consequence of this bifurcation is that Wolbachia may not persist, or dengue disease may not be effectively-controlled, when R0W is less than unity. Such persistence and elimination will depend on the initial sizes of the sub-populations of the model. Two mechanisms were identified for which the backward bifurcation phenomenon can be removed. When backward bifurcation does not occur, the associated non-trivial disease-free equilibrium is shown to be globally-asymptotically stable when the reproduction number of the model is less than unity. Numerical simulations, using data relevant to dengue transmission dynamics in northern Queensland, Australia, shows that releasing Wolbachia-infected mosquitoes every three weeks, for a one-year duration, can lead to the effective control of the of the population abundance of the local wild mosquitoes, and that such effective control increases with increasing number of Wolbachia-infected mosquitoes released (resulting in the reduction of over 90% of the wild mosquito population from their baseline values). Furthermore, simulations show that releasing only adult male Wolbachia-infected mosquitoes provide more beneficial population-level impact (in terms of reducing the population abundance of the wild mosquitoes), in comparison to releasing adult female Wolbachia-infected mosquitoes. Increasing the frequency of Wolbachia release (e.g., from the default release frequency of every three weeks to weekly) does not significantly affect the effectiveness of the Wolbachia-based control program in curtailing the local abundance of the wild mosquitoes. Finally, it was shown that the cytoplasmic incompatibility property of Wolbachia bacterium does not significantly affect the effectiveness of the Wolbachia-based mosquito control strategy implemented in the community.

RevDate: 2020-07-25

Crawford JE, Clarke DW, Criswell V, et al (2020)

Author Correction: Efficient production of male Wolbachia-infected Aedes aegypti mosquitoes enables large-scale suppression of wild populations.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

RevDate: 2020-07-27

Lindsey ARI (2020)

Sensing, Signaling, and Secretion: A Review and Analysis of Systems for Regulating Host Interaction in Wolbachia.

Genes, 11(7): pii:genes11070813.

Wolbachia (Anaplasmataceae) is an endosymbiont of arthropods and nematodes that resides within host cells and is well known for manipulating host biology to facilitate transmission via the female germline. The effects Wolbachia has on host physiology, combined with reproductive manipulations, make this bacterium a promising candidate for use in biological- and vector-control. While it is becoming increasingly clear that Wolbachia's effects on host biology are numerous and vary according to the host and the environment, we know very little about the molecular mechanisms behind Wolbachia's interactions with its host. Here, I analyze 29 Wolbachia genomes for the presence of systems that are likely central to the ability of Wolbachia to respond to and interface with its host, including proteins for sensing, signaling, gene regulation, and secretion. Second, I review conditions under which Wolbachia alters gene expression in response to changes in its environment and discuss other instances where we might hypothesize Wolbachia to regulate gene expression. Findings will direct mechanistic investigations into gene regulation and host-interaction that will deepen our understanding of intracellular infections and enhance applied management efforts that leverage Wolbachia.

RevDate: 2020-07-27

Krafsur AM, Ghosh A, CL Brelsfoard (2020)

Phenotypic Response of Wolbachia pipientis in a Cell-Free Medium.

Microorganisms, 8(7): pii:microorganisms8071060.

Wolbachia, an obligate intracellular bacterium estimated to infect millions of arthropod species worldwide, is currently being utilized in novel control strategies to limit the transmission of Dengue and Zika viruses. A limitation for Wolbachia-based control approaches is the difficulty of transferring Wolbachia to novel hosts and the lack of tools for the genetic transformation of Wolbachia due to the inability to culture Wolbachia outside the insect host cell in an axenic media. Here, we applied extracellular Wolbachia to phenotypic microarrays to measure the metabolic response of Wolbachia in media formulations with different pH levels and supplementation with Casamino acids. Results suggested a pH of 6.5-6.8 and showed that the supplementation of 1 mg/mL casamino acids increased the survival and longevity of Wolbachia in an axenic medium. In addition, phenotypic microarrays are a useful tool to measure the phenotypic response of Wolbachia under different media conditions, as well as determine specific components that may be required for an axenic medium. This study is an initial step toward the development of a potential Wolbachia axenic culture system.

RevDate: 2020-07-25

Calamoneri T, Gastaldello M, Mary A, et al (2020)

Algorithms for the quantitative Lock/Key model of cytoplasmic incompatibility.

Algorithms for molecular biology : AMB, 15:14.

Cytoplasmic incompatibility (CI) relates to the manipulation by the parasite Wolbachia of its host reproduction. Despite its widespread occurrence, the molecular basis of CI remains unclear and theoretical models have been proposed to understand the phenomenon. We consider in this paper the quantitative Lock-Key model which currently represents a good hypothesis that is consistent with the data available. CI is in this case modelled as the problem of covering the edges of a bipartite graph with the minimum number of chain subgraphs. This problem is already known to be NP-hard, and we provide an exponential algorithm with a non trivial complexity. It is frequent that depending on the dataset, there may be many optimal solutions which can be biologically quite different among them. To rely on a single optimal solution may therefore be problematic. To this purpose, we address the problem of enumerating (listing) all minimal chain subgraph covers of a bipartite graph and show that it can be solved in quasi-polynomial time. Interestingly, in order to solve the above problems, we considered also the problem of enumerating all the maximal chain subgraphs of a bipartite graph and improved on the current results in the literature for the latter. Finally, to demonstrate the usefulness of our methods we show an application on a real dataset.

RevDate: 2020-07-22

Ren W, Wei H, Yang Y, et al (2020)

Molecular detection and phylogenetic analyses of Wolbachia in natural populations of nine galling Aphid species.

Scientific reports, 10(1):12025 pii:10.1038/s41598-020-68925-z.

Wolbachia is one of the most abundant facultative intracellular symbionts in arthropods. It alters host biology in diverse ways, including the induction of reproductive manipulation, association of nutrient supplier and protection against pathogens. Aphids are a group of insects which exhibit interesting biological characteristics such as complex life cycles, alteration of sexual and asexual reproduction and shifts between two different hosts. Wolbachia is widely present in many orders of insects, but so far limited studies on Wolbachia in aphids have been carried out. Galling aphids are a group of aphids that induce galls on their primary host plants at specific life stage. In this study, 15 natural populations representing nine galling aphid species were analyzed for the presence of Wolbachia using species-specific primer pairs. Wolbachia presence in galling aphids was quite low and varied significantly among aphid populations. Only three of the 15 populations we analyzed had detectable Wolbachia and the overall infection rate was 20%. Two Wolbachia strains, O and B, were identified from the galling aphids Kaburagia rhusicola and Schlechtendalia chinensis. Strain O was for the first time to be found in aphids, and it is likely involved with the life stages of galling aphids living in closed microenvironments with specific survival strategies that are different from free-living aphids.

RevDate: 2020-07-21

Huang EYY, Wong AYP, Lee IHT, et al (2020)

Infection patterns of dengue, Zika and endosymbiont Wolbachia in the mosquito Aedes albopictus in Hong Kong.

Parasites & vectors, 13(1):361 pii:10.1186/s13071-020-04231-x.

BACKGROUND: The mosquito Aedes albopictus is a vector of dengue and Zika viruses. Insecticide-resistant mosquito populations have evolved in recent decades, suggesting that new control strategies are needed. Hong Kong has a monsoon-influenced humid subtropical climate, which favours the spread of mosquitoes. However, baseline information on the composition and dynamics of the occurrence of endosymbiont Wolbachia in local Ae. albopictus is lacking, hindering the development of scientifically-informed control measures. This study identifies the presence and absence of dengue and Zika viruses, and Wolbachia infection in Aedes albopictus in Hong Kong.

METHODS: Oviposition traps were set at 57 areas in Hong Kong, and both immature and adult mosquitoes were collected on a monthly basis between April 2018 and April 2019 as the study sample. Each individual mosquito in this sample was processed and screened for the presence of the dengue and Zika viruses and the endosymbionts Wolbachia wAlbA and wAlbB with PCR.

RESULTS: Totals of 967 and 984 mosquitoes were tested respectively for the presence of dengue and Zika viruses, and no trace of either infection was found in these samples. The presence of wAlbA and wAlbB was also tested in 1582 individuals. Over 80% of these individuals were found to be stably infected with Wolbachia throughout the thirteen-month collection period (~ 47% singly-infected; ~ 36.8% doubly infected with both wAlbA and wAlbB).

CONCLUSIONS: The high degree of Wolbachia wAlbA and wAlbB infection in Ae. albopictus mosquitoes in Hong Kong, coupled with the absence of any signs of infection by dengue and Zika viruses, contrasts significantly with the pattern of mosquito infection in other parts of Asia. Further studies of the infection pattern in local mosquitoes are warranted before mosquito control strategies used in other regions are implemented in Hong Kong.

RevDate: 2020-07-21

Morrow JL, Om N, Beattie GAC, et al (2020)

Characterization of the bacterial communities of psyllids associated with Rutaceae in Bhutan by high throughput sequencing.

BMC microbiology, 20(1):215 pii:10.1186/s12866-020-01895-4.

BACKGROUND: Several plant-pathogenic bacteria are transmitted by insect vector species that often also act as hosts. In this interface, these bacteria encounter plant endophytic, insect endosymbiotic and other microbes. Here, we used high throughput sequencing to examine the bacterial communities of five different psyllids associated with citrus and related plants of Rutaceae in Bhutan: Diaphorina citri, Diaphorina communis, Cornopsylla rotundiconis, Cacopsylla heterogena and an unidentified Cacopsylla sp.

RESULTS: The microbiomes of the psyllids largely comprised their obligate P-endosymbiont 'Candidatus Carsonella ruddii', and one or two S-endosymbionts that are fixed and specific to each lineage. In addition, all contained Wolbachia strains; the Bhutanese accessions of D. citri were dominated by a Wolbachia strain first found in American isolates of D. citri, while D. communis accessions were dominated by the Wolbachia strain, wDi, first detected in D. citri from China. The S-endosymbionts from the five psyllids grouped with those from other psyllid taxa; all D. citri and D. communis individuals contained sequences matching 'Candidatus Profftella armatura' that has previously only been reported from other Diaphorina species, and the remaining psyllid species contained OTUs related to unclassified Enterobacteriaceae. The plant pathogenic 'Candidatus Liberibacter asiaticus' was found in D. citri but not in D. communis. Furthermore, an unidentified 'Candidatus Liberibacter sp.' occurred at low abundance in both Co. rotundiconis and the unidentified Cacopsylla sp. sampled from Zanthoxylum sp.; the status of this new liberibacter as a plant pathogen and its potential plant hosts are currently unknown. The bacterial communities of Co. rotundiconis also contained a range of OTUs with similarities to bacteria previously found in samples taken from various environmental sources.

CONCLUSIONS: The bacterial microbiota detected in these Bhutanese psyllids support the trends that have been seen in previous studies: psyllids have microbiomes largely comprising their obligate P-endosymbiont and one or two S-endosymbionts. In addition, the association with plant pathogens has been demonstrated, with the detection of liberibacters in a known host, D. citri, and identification of a putative new species of liberibacter in Co. rotundiconis and Cacopsylla sp.

RevDate: 2020-07-17

Higazi TB, Geary TG, CD Mackenzie (2014)

Chemotherapy in the treatment, control, and elimination of human onchocerciasis.

Research and reports in tropical medicine, 5:77-93.

Onchocerciasis treatment is one of the most positive stories in tropical medicine although major challenges remain to reaching the ultimate goal of disease elimination. Such challenges are to be expected when the therapeutic goal is to kill and safely remove a large multistage, efficient, metazoan infectious agent such as Onchocerca volvulus that has an exceptionally complicated relationship with its host. Successful control of onchocerciasis has often been hampered by host reactions following chemotherapy, that can sometimes cause significant tissue pathology. Presence of other filariae, particularly Loa loa, in endemic onchocerciasis-treatment areas also poses severe problems due to adverse reactions caused by drug-induced death of the coincident microfilariae of this usually clinically benign species. Although ivermectin has been very successful, there is a need to enhance the progress toward elimination of onchocerciasis; new drugs and their efficient use are keys to this. The permanent absence of Onchocerca microfilaridermia, defined as the lack of resurgence of skin microfilarial loads after treatment, is the ultimate characteristic of a useful new chemotherapeutic agent. Several drugs are under investigation to achieve this, including the reassessment of currently available and previously tested agents, such as the antibiotic, doxycycline, which targets the adult parasites through its anti-Wolbachia endosymbiont activity. Flubendazole, a benzimidazole derivative approved for treatment of human gastrointestinal nematodes, is also being considered for repurposing as a macrofilaricide to aid in the achievement of eradication. The managerial challenges existing at the population level also need to be addressed; these include drug-distribution fatigue, the need to include noncompliant people, civil unrest in endemic areas, political cross-border issues, restrictions of age and pregnancy, and complications due to integration with other treatment programs. It is likely that a panel of chemotherapeutic options, new and old, supported by strong and effective distribution systems will be the best way to address challenges of treatment and elimination of this infection. Future research should also address management of treatment and control, and consider how new treatment paradigms can be incorporated to meet time lines set for global elimination by 2025.

RevDate: 2020-07-10

Nguyen HM, Theppannga W, Vongphayloth K, et al (2020)

Screening of ectoparasites from domesticated dogs for bacterial pathogens in Vientiane, Lao PDR.

Zoonoses and public health [Epub ahead of print].

Arthropod-borne diseases are widespread worldwide and are a complex interaction between animals, humans and ectoparasites. The understanding of the diversity and epidemiology of organisms transmitted by arthropod vectors, and the role of hosts and vectors in transmission of infections remain limited in Lao PDR. What knowledge does exist is primarily focused on more rural regions of the country. This study screened ectoparasites from domestic dogs in Vientiane city for the presence of bacterial pathogens of zoonotic importance. A total of 3,511 arthropod vectors were collected from 112 dogs. Vectors collected were Rhipicephalus sanguineus ticks, Ctenocephalides felis felis and Ctenocephalides felis orientis fleas and Heterodoxus spiniger lice. A sub-sample of vectors from each dog was analysed by PCR to identify the potential bacteria. From 129 vector pools, Rickettsia spp. was detected in 6.7% (7/105) pools of ticks, 86.4% (19/22) pools of fleas and both pools of lice. Sequencing analysis confirmed Rickettsia felis in 13 flea pools and one louse pool and Rickettsia asembonensis in six flea pools. Anaplasmataceae was identified in 14.3% (15/105) tick pools and 100% (22/22) flea pools. Sequencing revealed the presence of Anaplasma platys in ticks and Wolbachia pipientis in fleas. Leptospira spp. was detected in one tick and one louse pool, and Brucella spp. was detected in 12.4% (13/105) tick pools. All samples were negative for Bartonella spp., Coxiella burnetii and Borrelia burgdorferi. This is the first study providing evidence of R. asembonensis in fleas in Laos. Results from this study show arthropods are potential vectors to transmit zoonotic infection in Vientiane city, suggesting humans are at risk of zoonotic infections in the city.

RevDate: 2020-07-10

Félix ML, Armúa-Fernández MT, Parodi P, et al (2020)

Detection of a putative novel genotype of Anaplasma in gray-brocket deer (Mazama gouazoubira) from Uruguay.

Experimental & applied acarology pii:10.1007/s10493-020-00523-0 [Epub ahead of print].

Anaplasmataceae includes the genera Anaplasma, Ehrlichia, Neorickettsia and Wolbachia, comprising a group of obligate intracellular bacteria. The genus Anaplasma has pathogenic species transmitted by ticks of veterinary and human health importance. Wild ungulates such as deer represent important reservoirs and amplifiers of Anaplasmataceae. The interaction between deer and domestic ruminants represents a serious problem due to the transmission of these pathogens through their ectoparasites. In the present study, we investigated the presence of Anaplasmataceae organisms in blood, tissues and tick samples of a gray-brocket deer (Mazama gouazoubira). The specimen was found dead in a farm in northeast Uruguay. PCRs targeting partial regions of 16S rRNA and groESL genes were carried out for Anaplasmataceae DNA detection. Moreover, several ectoparasites were identified: the chewing louse Tricholipeurus albimarginatus, the Neotropical deer louse fly Lipoptena mazamae, and the ticks Haemaphysalis juxtakochi and Rhipicephalus microplus. A consensus sequence of 1274 bp of 16S rRNA was generated for Anaplasma sp. from the M. gouazoubira blood sample. All ticks analysed by PCR assays were negative. No band was detected in any of the samples after PCR targeting groESL gene. Phylogenetic analysis using 16S rRNA partial gene sequences, clustered the putative novel genotype sequence obtained in this study, named Anaplasma sp. genotype Mazama-Uruguay, along with Anaplasma sp. detected in Mazama sp., Mazama americana and Mazama bororo, all deer species from Brazil. Furthermore, this cluster showed to be closely related to Anaplasma bovis sequences obtained from various ruminants and other mammals from several parts of the world. The pathogenicity as well as its infecting potential to other cervids or domestic ruminants is currently unknown. Further studies should be performed in order to characterize this novel species, especially targeting other genes.

RevDate: 2020-07-09

Brady OJ, Kharisma DD, Wilastonegoro NN, et al (2020)

The cost-effectiveness of controlling dengue in Indonesia using wMel Wolbachia released at scale: a modelling study.

BMC medicine, 18(1):186 pii:10.1186/s12916-020-01638-2.

BACKGROUND: Release of virus-blocking Wolbachia-infected mosquitoes is an emerging disease control strategy that aims to control dengue and other arboviral infections. Early entomological data and modelling analyses have suggested promising outcomes, and wMel Wolbachia releases are now ongoing or planned in 12 countries. To help inform government, donor, or philanthropist decisions on scale-up beyond single city releases, we assessed this technology's cost-effectiveness under alternative programmatic options.

METHODS: Using costing data from existing Wolbachia releases, previous dynamic model-based estimates of Wolbachia effectiveness, and a spatially explicit model of release and surveillance requirements, we predicted the costs and effectiveness of the ongoing programme in Yogyakarta City and three new hypothetical programmes in Yogyakarta Special Autonomous Region, Jakarta, and Bali.

RESULTS: We predicted Wolbachia to be a highly cost-effective intervention when deployed in high-density urban areas with gross cost-effectiveness below $1500 per DALY averted. When offsets from the health system and societal perspective were included, such programmes even became cost saving over 10-year time horizons with favourable benefit-cost ratios of 1.35 to 3.40. Sequencing Wolbachia releases over 10 years could reduce programme costs by approximately 38% compared to simultaneous releases everywhere, but also delays the benefits. Even if unexpected challenges occurred during deployment, such as emergence of resistance in the medium-term or low effective coverage, Wolbachia would remain a cost-saving intervention.

CONCLUSIONS: Wolbachia releases in high-density urban areas are expected to be highly cost-effective and could potentially be the first cost-saving intervention for dengue. Sites with strong public health infrastructure, fiscal capacity, and community support should be prioritised.

RevDate: 2020-07-08

Liu G, Tan FH, Lau SA, et al (2020)

Lactic acid bacteria feeding reversed the malformed eye structures and ameliorated gut microbiota profiles of Drosophila melanogaster Alzheimer's Disease model.

Journal of applied microbiology [Epub ahead of print].

AIMS: To utilize transgenic GMR-Aβ42 Drosophila melanogaster as a model to evaluate potential Alzheimer's disease (AD)-reversal effects via the administration of lactic acid bacteria (LAB) strains, and associations of LAB with changes in gut microbiota profiles.

METHODS AND RESULTS: Wild type flies (Oregon-R) was crossed with glass multimer reporter-GAL4 (GMR-GAL4) to produce GMR-OreR (Control), while UAS-Aβ42 (#33769) crossed with GMR-GAL4 to produce transgenic Drosophila line that expressed Aβ42 (GMR-Aβ42). Feed containing seven different LAB strains (Lactobacillus paracasei 0291, Lactobacillus helveticus 1515, Lactobacillus reuteri CDV, Lactobacillus reuteri 8513d, Lactobacillus fermentum 8312, Lactobacillus casei Y, Lactobacillus sakei Probio65) were given to GMR-Aβ42 respectively, while feed without LAB strains were given to control and transgenic GMR-Aβ42.nf Drosophila lines. The morphology of the eyes was viewed with scanning electron microscopy (SEM). The changes in gut microbiota profiles associated with LAB were analyzed using 16s high throughput sequencing. Malformation of eye structures in transgenic GMR-Aβ42 Drosophila were reversed upon the administration of LAB strains, with more prevalent effects from Lactobacillus sakei Probio65 and Lactobacillus paracasei 0291. The GMR-Aβ42.nf group showed dominance of Wolbachia in the gut, a genus that was almost absent in the normal control group (P<0.05). The administration of L. sakei Probio65 and L. paracasei 0291 reduced the abundance of Wolbachia accompanied by increased abundance of Stenotrophomonas and Acetobacter (P<0.05), resembling the microbial profile of the control group.

CONCLUSIONS: L. sakei Probio65 and L. paracasei 0291 have more prominent effects in reversing malformed eye of transgenic GMR-Aβ42 Drosophila, and reducing the abundance of Wolbachia accompanied by an increased abundance of Stenotrophomonas and Acetobacter.

Potentials of LAB to prevent and/or alleviate the onset and pathogenesis of neurodegenerative diseases such as AD, supporting brain health strategies along the gut-brain axis.

RevDate: 2020-07-08

Gunderson EL, Vogel I, Chappell L, et al (2020)

The endosymbiont Wolbachia rebounds following antibiotic treatment.

PLoS pathogens, 16(7):e1008623 pii:PPATHOGENS-D-20-00474 [Epub ahead of print].

Antibiotic treatment has emerged as a promising strategy to sterilize and kill filarial nematodes due to their dependence on their endosymbiotic bacteria, Wolbachia. Several studies have shown that novel and FDA-approved antibiotics are efficacious at depleting the filarial nematodes of their endosymbiont, thus reducing female fecundity. However, it remains unclear if antibiotics can permanently deplete Wolbachia and cause sterility for the lifespan of the adult worms. Concerns about resistance arising from mass drug administration necessitate a careful exploration of potential Wolbachia recrudescence. In the present study, we investigated the long-term effects of the FDA-approved antibiotic, rifampicin, in the Brugia pahangi jird model of infection. Initially, rifampicin treatment depleted Wolbachia in adult worms and simultaneously impaired female worm fecundity. However, during an 8-month washout period, Wolbachia titers rebounded and embryogenesis returned to normal. Genome sequence analyses of Wolbachia revealed that despite the population bottleneck and recovery, no genetic changes occurred that could account for the rebound. Clusters of densely packed Wolbachia within the worm's ovarian tissues were observed by confocal microscopy and remained in worms treated with rifampicin, suggesting that they may serve as privileged sites that allow Wolbachia to persist in worms while treated with antibiotic. To our knowledge, these clusters have not been previously described and may be the source of the Wolbachia rebound.

RevDate: 2020-07-08

Rosenwald LC, Sitvarin MI, JA White (2020)

Endosymbiotic Rickettsiella causes cytoplasmic incompatibility in a spider host.

Proceedings. Biological sciences, 287(1930):20201107.

Many arthropod hosts are infected with bacterial endosymbionts that manipulate host reproduction, but few bacterial taxa have been shown to cause such manipulations. Here, we show that a bacterial strain in the genus Rickettsiella causes cytoplasmic incompatibility (CI) between infected and uninfected hosts. We first surveyed the bacterial community of the agricultural spider Mermessus fradeorum (Linyphiidae) using high throughput sequencing and found that individual spiders can be infected with up to five different strains of maternally inherited symbiont from the genera Wolbachia, Rickettsia, and Rickettsiella. The Rickettsiella strain was pervasive, found in all 23 tested spider matrilines. We used antibiotic curing to generate uninfected matrilines that we reciprocally crossed with individuals infected only with Rickettsiella. We found that only 13% of eggs hatched when uninfected females were mated with Rickettsiella-infected males; in contrast, at least 83% of eggs hatched in the other cross types. This is the first documentation of Rickettsiella, or any Gammaproteobacteria, causing CI. We speculate that induction of CI may be much more widespread among maternally inherited bacteria than previously appreciated. Further, our results reinforce the importance of thoroughly characterizing and assessing the inherited microbiome before attributing observed host phenotypes to well-characterized symbionts such as Wolbachia.

RevDate: 2020-07-07

Faria Waziry PA, Raja A, Salmon C, et al (2020)

Impact of pyriproxyfen on virus behavior: implications for pesticide-induced virulence and mechanism of transmission.

Virology journal, 17(1):93 pii:10.1186/s12985-020-01378-y.

BACKGROUND: More than 3 years since the last Zika virus (ZIKV) outbreak in Brazil, researchers are still deciphering the molecular mechanisms of neurovirulence and vertical transmission, as well as the best way to control spread of ZIKV, a flavivirus. The use of pesticides was the main strategy of mosquito control during the last ZIKV outbreak.

METHODS: We used vesicular stomatitis virus (VSV) tagged with green fluorescent protein (GFP) as our prototypical virus to study the impact of insecticide pyriproxyfen (PPF). VZV-GFP infected and uninfected Jurkat, HeLa and trophoblast cells were treated with PPF and compared to untreated cells (control). Cell viability was determined by the MTT assay. Cell morphology, presence of extracellular vesicles (EVs), virus infection/GFP expression as well as active mitochondrial levels/localization were examined by confocal microscopy.

RESULTS: PPF, which was used to control mosquito populations in Brazil prior to the ZIKV outbreak, enhances VSV replication and has cell membrane-altering properties in the presence of virus. PPF causes enhanced viral replication and formation of large EVs, loaded with virus as well as mitochondria. Treatment of trophoblasts or HeLa cells with increasing concentrations of PPF does not alter cell viability, however, it proportionately increases Jurkat cell viability. Increasing concentrations of PPF followed by VSV infection does not interfere with HeLa cell viability. Both Jurkats and trophoblasts show proportionately increased cell death with increased concentrations of PPF in the presence of virus.

CONCLUSIONS: We hypothesize that PPF disrupts the lipid microenvironment of mammalian cells, thereby interfering with pathways of viral replication. PPF lowers viability of trophoblasts and Jurkats in the presence of VSV, implying that the combination renders immune system impairment in infected individuals as well as enhanced vulnerability of fetuses towards viral vertical transmission. We hypothesize that similar viruses such as ZIKV may be vertically transmitted via EV-to-cell contact when exposed to PPF, thereby bypassing immune detection. The impact of pesticides on viral replication must be fully investigated before large scale use in future outbreaks of mosquito borne viruses.

RevDate: 2020-07-07

Khoo JJ, Kurtti TJ, Husin NA, et al (2020)

Isolation and Propagation of Laboratory Strains and a Novel Flea-Derived Field Strain of Wolbachia in Tick Cell Lines.

Microorganisms, 8(7): pii:microorganisms8070988.

Wolbachia are intracellular endosymbionts of several invertebrate taxa, including insects and nematodes. Although Wolbachia DNA has been detected in ticks, its presence is generally associated with parasitism by insects. To determine whether or not Wolbachia can infect and grow in tick cells, cell lines from three tick species, Ixodes scapularis, Ixodes ricinus and Rhipicephalus microplus, were inoculated with Wolbachia strains wStri and wAlbB isolated from mosquito cell lines. Homogenates prepared from fleas collected from cats in Malaysia were inoculated into an I. scapularis cell line. Bacterial growth and identity were monitored by microscopy and PCR amplification and sequencing of fragments of Wolbachia genes. The wStri strain infected Ixodes spp. cells and was maintained through 29 passages. The wAlbB strain successfully infected Ixodes spp. and R. microplus cells and was maintained through 2-5 passages. A novel strain of Wolbachia belonging to the supergroup F, designated wCfeF, was isolated in I. scapularis cells from a pool of Ctenocephalides sp. cat fleas and maintained in vitro through two passages over nine months. This is the first confirmed isolation of a Wolbachia strain from a flea and the first isolation of any Wolbachia strain outside the "pandemic" A and B supergroups. The study demonstrates that tick cells can host multiple Wolbachia strains, and can be added to panels of insect cell lines to improve success rates in isolation of field strains of Wolbachia.

RevDate: 2020-07-03

Lebov JF, Mattick J, Libro S, et al (2020)

Complete Genome Sequence of wBp, the Wolbachia Endosymbiont of Brugia pahangi FR3.

Microbiology resource announcements, 9(27): pii:9/27/e00480-20.

Lymphatic filariasis is a devastating disease caused by filarial nematode roundworms, which contain obligate Wolbachia endosymbionts. Here, we assembled the genome of wBp, the Wolbachia endosymbiont of the filarial nematode Brugia pahangi, from Illumina, Pacific Biosciences, and Oxford Nanopore data. The complete, circular genome is 1,072,967 bp.

RevDate: 2020-07-03

Duan XZ, Sun JT, Wang LT, et al (2020)

Recent infection by Wolbachia alters microbial communities in wild Laodelphax striatellus populations.

Microbiome, 8(1):104 pii:10.1186/s40168-020-00878-x.

BACKGROUND: Host-associated microbial communities play an important role in the fitness of insect hosts. However, the factors shaping microbial communities in wild populations, including genetic background, ecological factors, and interactions among microbial species, remain largely unknown.

RESULTS: Here, we surveyed microbial communities of the small brown planthopper (SBPH, Laodelphax striatellus) across 17 geographical populations in China and Japan by using 16S rRNA amplicon sequencing. Using structural equation models (SEM) and Mantel analyses, we show that variation in microbial community structure is likely associated with longitude, annual mean precipitation (Bio12), and mitochondrial DNA variation. However, a Wolbachia infection, which is spreading to northern populations of SBPH, seems to have a relatively greater role than abiotic factors in shaping microbial community structure, leading to sharp decreases in bacterial taxon diversity and abundance in host-associated microbial communities. Comparative RNA-Seq analyses between Wolbachia-infected and -uninfected strains indicate that the Wolbachia do not seem to alter the immune reaction of SBPH, although Wolbachia affected expression of metabolism genes.

CONCLUSION: Together, our results identify potential factors and interactions among different microbial species in the microbial communities of SBPH, which can have effects on insect physiology, ecology, and evolution. Video Abstract.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Caragata EP, Tikhe CV, G Dimopoulos (2019)

Curious entanglements: interactions between mosquitoes, their microbiota, and arboviruses.

Current opinion in virology, 37:26-36.

Mosquitoes naturally harbor a diverse community of microorganisms that play a crucial role in their biology. Mosquito-microbiota interactions are abundant and complex. They can dramatically alter the mosquito immune response, and impede or enhance a mosquito's ability to transmit medically important arboviral pathogens. Yet critically, given the massive public health impact of arboviral disease, few such interactions have been well characterized. In this review, we describe the current state of knowledge of the role of microorganisms in mosquito biology, how microbial-induced changes to mosquito immunity moderate infection with arboviruses, cases of mosquito-microbial-virus interactions with a defined mechanism, and the molecular interactions that underlie the endosymbiotic bacterium Wolbachia's ability to block virus infection in mosquitoes.

RevDate: 2020-07-01

Lefoulon E, Clark T, Borveto F, et al (2020)

Pseudoscorpion Wolbachia symbionts: diversity and evidence for a new supergroup S.

BMC microbiology, 20(1):188 pii:10.1186/s12866-020-01863-y.

BACKGROUND: Wolbachia are the most widely spread endosymbiotic bacteria, present in a wide variety of insects and two families of nematodes. As of now, however, relatively little genomic data has been available. The Wolbachia symbiont can be parasitic, as described for many arthropod systems, an obligate mutualist, as in filarial nematodes or a combination of both in some organisms. They are currently classified into 16 monophyletic lineage groups ("supergroups"). Although the nature of these symbioses remains largely unknown, expanded Wolbachia genomic data will contribute to understanding their diverse symbiotic mechanisms and evolution.

RESULTS: This report focuses on Wolbachia infections in three pseudoscorpion species infected by two distinct groups of Wolbachia strains, based upon multi-locus phylogenies. Geogarypus minor harbours wGmin and Chthonius ischnocheles harbours wCisc, both closely related to supergroup H, while Atemnus politus harbours wApol, a member of a novel supergroup S along with Wolbachia from the pseudoscorpion Cordylochernes scorpioides (wCsco). Wolbachia supergroup S is most closely related to Wolbachia supergroups C and F. Using target enrichment by hybridization with Wolbachia-specific biotinylated probes to capture large fragments of Wolbachia DNA, we produced two draft genomes of wApol. Annotation of wApol highlights presence of a biotin operon, which is incomplete in many sequenced Wolbachia genomes.

CONCLUSIONS: The present study highlights at least two symbiont acquisition events among pseudoscorpion species. Phylogenomic analysis indicates that the Wolbachia from Atemnus politus (wApol), forms a separate supergroup ("S") with the Wolbachia from Cordylochernes scorpioides (wCsco). Interestingly, the biotin operon, present in wApol, appears to have been horizontally transferred multiple times along Wolbachia evolutionary history.

RevDate: 2020-07-01

Kirik H, Tummeleht L, Lilja T, et al (2020)

Novel Mitochondrial DNA Lineage Found among Ochlerotatus communis (De Geer, 1776) of the Nordic-Baltic Region.

Insects, 11(6): pii:insects11060397.

The Ochlerotatus (Oc.) communis complex consist of three Northern American species as well as a common Holarctic mosquito (Diptera: Culicidae) Oc. communis (De Geer, 1776). These sister species exhibit important ecological differences and are capable of transmitting various pathogens, but cannot always be differentiated by morphological traits. To investigate the Oc. communis complex in Europe, we compared three molecular markers (COI, ND5 and ITS2) from 54 Estonian mosquitoes as well as two COI marker sequences from Sweden. These sequences were subjected to phylogenetic analysis and screened for Wolbachia Hertig and Wolbach symbionts. Within and between groups, distances were calculated for each marker to better understand the relationships among individuals. Results demonstrate that a group of samples, extracted from adult female mosquitoes matching the morphology of Oc. communis, show a marked difference from the main species when comparing the mitochondrial markers COI and ND5. However, there is no variance between the same specimens when considering the nuclear ITS2. We conclude that Oc. communis encompasses two distinct mitochondrial DNA lineages in the Nordic-Baltic region. Further research is needed to investigate the origin and extent of these genetic differences.

RevDate: 2020-06-30

Herran B, Geniez S, Delaunay C, et al (2020)

The shutting down of the insulin pathway: a developmental window for Wolbachia load and feminization.

Scientific reports, 10(1):10551 pii:10.1038/s41598-020-67428-1.

Using the isopod Armadillidium vulgare as a case study, we review the significance of the "bacterial dosage model", which connects the expression of the extended phenotype to the rise of the Wolbachia load. In isopods, the Insulin-like Androgenic Gland hormone (IAG) induces male differentiation: Wolbachia feminizes males through insulin resistance, presumably through defunct insulin receptors. This should prevent an autocrine development of the androgenic glands so that females differentiate instead: feminization should translate as IAG silencing and increased Wolbachia load in the same developmental window. In line with the autocrine model, uninfected males expressed IAG from the first larval stage on, long before the androgenic gland primordia begin to differentiate, and exponentially throughout development. In contrast in infected males, expression fully stopped at stage 4 (juvenile), when male differentiation begins. This co-occurred with the only significant rise in the Wolbachia load throughout the life-stages. Concurrently, the raw expression of the bacterial Secretion Systems co-increased, but they were not over-expressed relative to the number of bacteria. The isopod model leads to formulate the "bacterial dosage model" throughout extended phenotypes as the conjunction between bacterial load as the mode of action, timing of multiplication (pre/post-zygotic), and site of action (soma vs. germen).

RevDate: 2020-06-29

Ferreira AG, Fairlie S, LA Moreira (2020)

Insect vectors endosymbionts as solutions against diseases.

Current opinion in insect science, 40:56-61 pii:S2214-5745(20)30078-X [Epub ahead of print].

Viral diseases transmitted by mosquitoes, known as arboviruses, pose a significant threat to human life and are a major burden on many health systems around the world. Currently, arbovirus control strategies rely on insecticides or vector source reduction and, in the absence of effective, accessible and affordable vaccines, mainly on symptomatic based, non-specific treatments. However, insecticides have the potential to interfere with non-target organisms, cause environmental toxicity and insecticide resistance reduces their effectiveness as a sustainable control method. Complementary and sustainable strategies are urgently needed. Wolbachia, an invertebrate endosymbiont, has been used as an alternative strategy for arboviral control, through suppression or modification of mosquito populations. Here we discuss the burden that arboviruses impose on human populations and how Wolbachia can be used as a sustainable strategy for control, in alignment with the United Nations- 2030 Agenda for Sustainable Development.

RevDate: 2020-06-30

Liu Y, Guo Z, El Smaily M, et al (2020)

A Wolbachia infection model with free boundary.

Journal of biological dynamics, 14(1):515-542.

Scientists have been seeking ways to use Wolbachia to eliminate the mosquitoes that spread human diseases. Could Wolbachia be the determining factor in controlling the mosquito-borne infectious diseases? To answer this question mathematically, we develop a reaction-diffusion model with free boundary in a one-dimensional environment. We divide the female mosquito population into two groups: one is the uninfected mosquito population that grows in the whole region while the other is the mosquito population infected with Wolbachia that occupies a finite small region. The mosquito population infected with Wolbachia invades the environment with a spreading front governed by a free boundary satisfying the well-known one-phase Stefan condition. For the resulting free boundary problem, we establish criteria under which spreading and vanishing occur. Our results provide useful insights on designing a feasible mosquito releasing strategy that infects the whole mosquito population with Wolbachia and eradicates the mosquito-borne diseases eventually.

RevDate: 2020-06-26

Ajene IJ, Khamis FM, van Asch B, et al (2020)

Microbiome diversity in Diaphorina citri populations from Kenya and Tanzania shows links to China.

PloS one, 15(6):e0235348 pii:PONE-D-20-04601.

The Asian citrus psyllid (Diaphorina citri) is a key pest of Citrus spp. worldwide, as it acts as a vector for "Candidatus Liberibacter asiaticus (Las)", the bacterial pathogen associated with the destructive Huanglongbing (HLB) disease. Recent detection of D. citri in Africa and reports of Las-associated HLB in Ethiopia suggest that the citrus industry on the continent is under imminent threat. Endosymbionts and gut bacteria play key roles in the biology of arthropods, especially with regards to vector-pathogen interactions and resistance to antibiotics. Thus, we aim to profile the bacterial genera and to identify antibiotic resistance genes within the microbiome of different populations worldwide of D. citri. The metagenome of D. citri was sequenced using the Oxford Nanopore full-length 16S metagenomics protocol, and the "What's in my pot" (WIMP) analysis pipeline. Microbial diversity within and between D. citri populations was assessed, and antibiotic resistance genes were identified using the WIMP-ARMA workflow. The most abundant genera were key endosymbionts of D. citri ("Candidatus Carsonella", "Candidatus Profftella", and Wolbachia). The Shannon diversity index showed that D. citri from Tanzania had the highest diversity of bacterial genera (1.92), and D. citri from China had the lowest (1.34). The Bray-Curtis dissimilarity showed that China and Kenya represented the most diverged populations, while the populations from Kenya and Tanzania were the least diverged. The WIMP-ARMA analyses generated 48 CARD genes from 13 bacterial species in each of the populations. Spectinomycin resistance genes were the most frequently found, with an average of 65.98% in all the populations. These findings add to the knowledge on the diversity of the African D. citri populations and the probable introduction source of the psyllid in these African countries.

RevDate: 2020-06-26

Aydın MF, Altay K, Aytmirzakizi A, et al (2020)

First Molecular Detection of Dirofilaria immitis and D. repens in Dogs from Kyrgyzstan.

Acta parasitologica pii:10.1007/s11686-020-00245-8 [Epub ahead of print].

BACKGROUND: Dirofilaria immitis and Dirofilaria repens are the causative agents of cardiopulmonary and subcutaneous dirofilariosis, respectively. This neglected disease mainly seen in dogs, cats and wild carnivores is re-emerging recent years. No study was conducted on dirofilariosis in dogs in Kyrgyzstan.

PURPOSE: The goal of this study was to investigate Dirofilaria species using PCR and sequencing in dogs from Kyrgyzstan.

METHOD: Dirofilaria spp. infection in dogs was screened via convential PCR and sequencing in 337 dogs from Kyrgyzstan.

RESULT: The overall prevalence of Dirofilaria spp. was 0.59% (2/337): DNA of D. immitis was detected in one sample and DNA of D. repens in second positive sample. In second sample, parallel co-infection of D. repens with Wolbachia was also found. While D. immitis sequence showed 98.70-100% similarity with previously reported sequences of D. immitis from dog blood, D. repens shared 100% identity with other sequences of D. repens.

CONCLUSION: These results provided first evidence for Dirofilaria spp. in Kyrgyzstan and emphasized the veterinary and medical importance.

RevDate: 2020-06-25

Mateos M, Martinez Montoya H, Lanzavecchia SB, et al (2020)

Wolbachia pipientis Associated With Tephritid Fruit Fly Pests: From Basic Research to Applications.

Frontiers in microbiology, 11:1080.

Members of the true fruit flies (family Tephritidae) are among the most serious agricultural pests worldwide, whose control and management demands large and costly international efforts. The need for cost-effective and environmentally friendly integrated pest management (IPM) has led to the development and implementation of autocidal control strategies. These approaches include the widely used sterile insect technique and the incompatible insect technique (IIT). IIT relies on maternally transmitted bacteria (namely Wolbachia) to cause a conditional sterility in crosses between released mass-reared Wolbachia-infected males and wild females, which are either uninfected or infected with a different Wolbachia strain (i.e., cytoplasmic incompatibility; CI). Herein, we review the current state of knowledge on Wolbachia-tephritid interactions including infection prevalence in wild populations, phenotypic consequences, and their impact on life history traits. Numerous pest tephritid species are reported to harbor Wolbachia infections, with a subset exhibiting high prevalence. The phenotypic effects of Wolbachia have been assessed in very few tephritid species, due in part to the difficulty of manipulating Wolbachia infection (removal or transinfection). Based on recent methodological advances (high-throughput DNA sequencing) and breakthroughs concerning the mechanistic basis of CI, we suggest research avenues that could accelerate generation of necessary knowledge for the potential use of Wolbachia-based IIT in area-wide integrated pest management (AW-IPM) strategies for the population control of tephritid pests.

RevDate: 2020-06-25

Khadka S, Proshad R, Thapa A, et al (2020)

Wolbachia: a possible weapon for controlling dengue in Nepal.

Tropical medicine and health, 48:50 pii:237.

Dengue, a mosquito-borne viral infectious disease, causes a high morbidity and mortality in tropical and subtropical areas of the world. In Nepal, the first case of dengue was reported in 2004 followed by frequent outbreaks in subsequent years, with the largest being in 2019 taking the death toll of six. It is reported that the number of dengue fever cases are soaring in Nepal spreading from the plains to more hilly regions. This might have serious public health implications in the future when combined with other factors, such as: global warming, lack of early detection and treatment of dengue, lack of diagnostic facilities, poor healthcare systems and mosquito control strategies. Nepal, thus, needs a cost-effective mosquito control strategy for the prevention and control of dengue. The Wolbachia-mediated biological method of the dengue control strategy is novel, economic, and environment-friendly. It has been successfully trialed in several areas of dengue-prone countries of the world, including Australia, Malaysia, Vietnam etc. resulting in significant reductions in dengue incidence. Given the lack of effective vector control strategy and weak economic condition of the country along with the persistence of climate and environment conditions that favors the host (Aedes mosquito) for Wolbachia, this approach can be a promising option to control dengue in Nepal.

RevDate: 2020-06-23

Lucek K, Butlin R, T Patsiou (2020)

Narrow phenotypic and parasitic clines shape secondary contact zones of closely-related Erebia butterflies.

Journal of evolutionary biology [Epub ahead of print].

Zones of secondary contact between closely related taxa are a common legacy of the Quaternary ice ages. Despite their abundance, the factors that keep species apart and prevent hybridisation are often unknown. Here we study a very narrow contact zone between three closely related butterfly species of the Erebia tyndarus species complex. Using genomic data, we first determined if gene flow occurs and then assessed whether it might be hampered by differences in chromosome number between some species. We found interspecific gene flow between sibling species that differ in karyotype by one chromosome. Conversely, only F1 hybrids occurred between two species that have the same karyotype, forming a steep genomic cline. In a second step, we fitted clines to phenotypic, ecological and parasitic data to identify the factors associated with the genetic cline. We found clines for phenotypic data and the prevalence of the endosymbiont parasite Wolbachia to overlap with the genetic cline, suggesting that they might be drivers for separating the two species. Overall our results highlight that some gene flow is possible between closely-related species despite different chromosome numbers, but that other barriers restrict such gene flow.

RevDate: 2020-06-23

Wang X, Kelkar YD, Xiong X, et al (2020)

Genome Report: Whole Genome Sequence and Annotation of the Parasitoid Jewel Wasp Nasonia giraulti Laboratory Strain RV2X[υ].

G3 (Bethesda, Md.) pii:g3.120.401200 [Epub ahead of print].

Jewel wasps in the genus of Nasonia are parasitoids with haplodiploidy sex determination, rapid development and are easy to culture in the laboratory. They are excellent models for insect genetics, genomics, epigenetics, development, and evolution. Nasonia vitripennis (Nv) and N. giraulti (Ng) are closely-related species that can be intercrossed, particularly after removal of the intracellular bacterium Wolbachia, which serve as a powerful tool to map and positionally clone morphological, behavioral, expression and methylation phenotypes. The Nv reference genome was assembled using Sanger, PacBio and Nanopore approaches and annotated with extensive RNA-seq data. In contrast, Ng genome is only available through low coverage resequencing. Therefore, de novoNg assembly is in urgent need to advance this system. In this study, we report a high-quality Ng assembly using 10X Genomics linked-reads with 670X sequencing depth. The current assembly has a genome size of 259,040,977 bp in 3,160 scaffolds with 38.05% G-C and a 98.6% BUSCO completeness score. 97% of the RNA reads are perfectly aligned to the genome, indicating high quality in contiguity and completeness. A total of 14,777 genes are annotated in the Ng genome, and 72% of the annotated genes have a one-to-one ortholog in the Nv genome. We reported 5 million Ng-Nv SNPs which will facility mapping and population genomic studies in Nasonia In addition, 42 Ng-specific genes were identified by comparing with Nv genome and annotation. This is the first de novo assembly for this important species in the Nasonia model system, providing a useful new genomic toolkit.

RevDate: 2020-06-23

Laidoudi Y, Davoust B, Varloud M, et al (2020)

Development of a multiplex qPCR-based approach for the diagnosis of Dirofilaria immitis, D. repens and Acanthocheilonema reconditum.

Parasites & vectors, 13(1):319 pii:10.1186/s13071-020-04185-0.

BACKGROUND: Dirofilaria immitis, D. repens and Acanthocheilonema reconditum are the main causative agents of zoonotic canine filariosis.

METHODS: We developed a combined multiplex approach for filaria and Wolbachia detection using the 28S-based pan-filarial and 16S-based pan-Wolbachia qPCRs, respectively, involving a fast typing method of positive samples using triplex qPCR targeting A. reconditum, D. immitis and D. repens, and a duplex qPCR targeting Wolbachia of D. immitis and D. repens. The approach was complemented by a duplex qPCR for the differential diagnosis of heartworms (D. immitis and Angiostrongylus vasorum) and pan-filarial cox1 and pan-Wolbachia ftsZ PCRs to identify other filarial parasites and their Wolbachia, respectively. A total of 168 canine blood and sera samples were used to validate the approach. Spearman's correlation was used to assess the association between filarial species and the strain of Wolbachia. Positive samples for both the heartworm antigen-test after heating sera and at least one DNA-positive for D. immitis and its Wolbachia were considered true positive for heartworm infection. Indeed, the presence of D. repens DNA or that of its Wolbachia as well as A. reconditum DNA indicates true positive infections.

RESULTS: The detection limit for Wolbachia and filariae qPCRs ranged from 5 × 10-1 to 1.5 × 10-4 mf/ml of blood. When tested on clinical samples, 29.2% (49/168) tested positive for filariae or Wolbachia DNA. Filarial species and Wolbachia genotypes were identified by the combined multiplex approach from all positive samples. Each species of Dirofilaria was significantly associated with a specific genotype of Wolbachia. Compared to the true positives, the approach showed excellent agreement (k = 0.98-1). Unlike D. immitis DNA, no A. vasorum DNA was detected by the duplex qPCR. The immunochromatographic test for heartworm antigen showed a substantial (k = 0.6) and a weak (k = 0.15) agreements before and after thermal pre-treatment of sera, respectively.

CONCLUSIONS: The proposed approach is a reliable tool for the exploration and diagnosis of occult and non-occult canine filariosis. The current diagnosis of heartworm disease based on antigen detection should always be confirmed by qPCR essays. Sera heat pre-treatment is not effective and strongly discouraged.

RevDate: 2020-06-20

Driscoll TP, Verhoeve VI, Gillespie JJ, et al (2020)

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity.

BMC biology, 18(1):70 pii:10.1186/s12915-020-00802-7.

BACKGROUND: Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus). The lack of flea genome assemblies has hindered research, especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the cat flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance across the globe.

RESULTS: By combining Illumina and PacBio sequencing of DNA derived from multiple inbred female fleas with Hi-C scaffolding techniques, we generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly revealed extensive gene duplication across the entire genome, exemplified by ~ 38% of protein-coding genes with two or more copies and over 4000 tRNA genes. A broad range of genome size determinations (433-551 Mb) for individual fleas sampled across different populations supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. Similarly, broad genome sizes were also calculated for individuals of Xenopsylla cheopis (Oriental rat flea), indicating that this remarkable "genome-in-flux" phenomenon could be a siphonapteran-wide trait. Finally, from the C. felis sequence reads, we also generated closed genomes for two novel strains of Wolbachia, one parasitic and one symbiotic, found to co-infect individual fleas.

CONCLUSION: Rampant CNV in C. felis has dire implications for gene-targeting pest control measures and stands to complicate standard normalization procedures utilized in comparative transcriptomics analysis. Coupled with co-infection by novel Wolbachia endosymbionts-potential tools for blocking pathogen transmission-these oddities highlight a unique and underappreciated disease vector.

RevDate: 2020-06-19

Wangkeeree J, Tewaruxsa P, Roddee J, et al (2020)

Wolbachia (Rickettsiales: Alphaproteobacteria) Infection in the Leafhopper Vector of Sugarcane White Leaf Disease.

Journal of insect science (Online), 20(3):.

Wolbachia is a maternally inherited bacterium ubiquitous in insects that has attracted interest as a prospective insect pest-control agent. Here, we detected and characterized Wolbachia in the leafhoppers Matsumuratettix hiroglyphicus (Matsumura) (Cicadellidae: Hemiptera) and Yamatotettix flavovittatus Matsumura (Cicadellidae: Hemiptera), insect vectors of the phytoplasma that cause white leaf disease in sugarcane. The 16S rRNA and wsp gene markers revealed that Wolbachia was not present in the M. hiroglyphicus but naturally occurs in Y. flavovittatus. Additionally, the infection rates in adult leafhoppers ranged from 0 to 100% depending on geographic location. Moreover, Wolbachia was detected in the eggs and first- to fifth-instar nymphs of Y. flavovittatus. A phylogenic tree of Wolbachia indicated that it resided in the monophyletic supergroup B clade and clustered in the Ori subgroup. Furthermore, fluorescence in situ hybridization revealed that Wolbachia localized to the egg apices, randomly distributed in the egg cytoplasm, and was concentrated in the nymph and adult bacteriomes, as well as occasional detection in the thorax and abdomen. To the best of our knowledge, the present study is the first to demonstrate the prevalence of Wolbachia in the leafhopper Y. flavovittatus. The obtained results would provide useful information for the future development of Wolbachia as a biological control agent for the leafhopper vectors.

RevDate: 2020-06-19

Bhattacharya T, Newton ILG, RW Hardy (2020)

Viral RNA is a target for Wolbachia-mediated pathogen blocking.

PLoS pathogens, 16(6):e1008513 pii:PPATHOGENS-D-20-00601 [Epub ahead of print].

The ability of the endosymbiont Wolbachia pipientis to restrict RNA viruses is presently being leveraged to curb global transmission of arbovirus-induced diseases. Past studies have shown that virus replication is limited early in arthropod cells colonized by the bacterium, although it is unclear if this phenomenon is replicated in mosquito cells that first encounter viruses obtained through a vertebrate blood meal. Furthermore, these cellular events neither explain how Wolbachia limits dissemination of viruses between mosquito tissues, nor how it prevents transmission of infectious viruses from mosquitoes to vertebrate host. In this study, we try to address these issues using an array of mosquito cell culture models, with an additional goal being to identify a common viral target for pathogen blocking. Our results establish the viral RNA as a cellular target for Wolbachia-mediated inhibition, with the incoming viral RNA experiencing rapid turnover following internalization in cells. This early block in replication in mosquito cells initially infected by the virus thus consequently reduces the production of progeny viruses from these same cells. However, this is not the only contributor to pathogen blocking. We show that the presence of Wolbachia reduces the per-particle infectivity of progeny viruses on naïve mosquito and vertebrate cells, consequently limiting virus dissemination and transmission, respectively. Importantly, we demonstrate that this aspect of pathogen blocking is independent of any particular Wolbachia-host association and affects viruses belonging to Togaviridae and Flaviviridae families of RNA viruses. Finally, consistent with the idea of the viral RNA as a target, we find that the encapsidated virion RNA is less infectious for viruses produced from Wolbachia-colonized cells. Collectively, our findings present a common mechanism of pathogen blocking in mosquitoes that establish a link between virus inhibition in the cell to virus dissemination and transmission.

RevDate: 2020-06-17

Hague MTJ, Mavengere H, Matute DR, et al (2020)

Environmental and Genetic Contributions to Imperfect wMel-Like Wolbachia Transmission and Frequency Variation.

Genetics pii:genetics.120.303330 [Epub ahead of print].

Maternally transmitted Wolbachia bacteria infect about half of all insect species. They usually show imperfect maternal transmission and often produce cytoplasmic incompatibility (CI). Irrespective of CI, Wolbachia frequencies tend to increase when rare only if they benefit host fitness. Several Wolbachia, including wMel that infects Drosophila melanogaster cause weak or no CI and persist at intermediate frequencies. On the island of São Tomé off West Africa, the frequencies of wMel-like Wolbachia infecting D. yakuba (wYak) and D. santomea (wSan) fluctuate, and the contributions of imperfect maternal transmission, fitness effects, and CI to these fluctuations are unknown. We demonstrate spatial variation in wYak frequency and transmission on São Tomé. Concurrent field estimates of imperfect maternal transmission do not predict spatial variation in wYak frequencies, which are highest at high altitudes where maternal transmission is the most imperfect. Genomic and genetic analyses provide little support for D. yakuba effects on wYak transmission. Instead, rearing at cool temperatures reduces wYak titer and increases imperfect transmission to levels observed on São Tomé. Using mathematical models of Wolbachia frequency dynamics and equilibria, we infer temporally variable imperfect transmission or spatially variable effects on host fitness and reproduction are required to explain wYak frequencies. In contrast, spatially stable wSan frequencies are plausibly explained by imperfect transmission, modest fitness effects, and weak CI. Our results provide insight into causes of wMel-like frequency variation in divergent hosts. Understanding this variation is crucial to explain Wolbachia spread and to improve wMel biocontrol of human disease in transinfected mosquito systems.

RevDate: 2020-06-17

Suwantika AA, Kautsar AP, Supadmi W, et al (2020)

Cost-Effectiveness of Dengue Vaccination in Indonesia: Considering Integrated Programs with Wolbachia-Infected Mosquitos and Health Education.

International journal of environmental research and public health, 17(12): pii:ijerph17124217.

Despite the fact that morbidity and mortality rates due to dengue infection in Indonesia are relatively high, a dengue vaccination has not yet been introduced. Next to vaccination, Wolbachia-infected mosquitoes and health education have been considered to be potential interventions to prevent dengue infection in Indonesia. This study was aimed to analyse the cost-effectiveness of dengue vaccination in Indonesia whilst taking Wolbachia and health education programs into account. An age-structured decision tree model was developed to assess the cost-effectiveness. Approximately 4,701,100 children were followed-up in a 10-year time horizon within a 1-year analytical cycle. We compared three vaccination strategies: one focussing on vaccination only, another combining vaccination and a Wolbachia program, and a third scenario combining vaccination and health education. All scenarios were compared with a no-intervention strategy. The result showed that only vaccination would reduce dengue fever (DF), dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS) by 123,203; 97,140 and 283 cases, respectively. It would save treatment cost at $10.3 million and $6.2 million from the healthcare and payer perspectives, respectively. The combination of vaccination and a Wolbachia program would reduce DF, DHF and DSS by 292,488; 230,541; and 672 cases, respectively. It would also save treatment cost at $24.3 million and $14.6 million from the healthcare and payer perspectives, respectively. The combination of vaccination and health education would reduce DF, DHF, and DSS by 187,986; 148,220; and 432 cases, respectively. It would save treatment cost at $15.6 million and $9.4 million from the healthcare and payer perspectives, respectively. The incremental cost-effectiveness ratios (ICERs) from the healthcare perspective were estimated to be $9,995, $4,460, and $6,399 per quality-adjusted life year (QALY) gained for the respective scenarios. ICERs from the payer perspective were slightly higher. It can be concluded that vaccination combined with a Wolbachia program was confirmed to be the most cost-effective intervention. Dengue infection rate, vaccine efficacy, cost of Wolbachia program, underreporting factor for hospitalization, vaccine price and mortality rate were considered to be the most influential parameters affecting the ICERs.

RevDate: 2020-06-12

Staunton KM, Crawford JE, Cornel D, et al (2020)

Environmental influences on Aedes aegypti catches in Biogents Sentinel traps during a Californian "rear and release" program: Implications for designing surveillance programs.

PLoS neglected tropical diseases, 14(6):e0008367 pii:PNTD-D-20-00109 [Epub ahead of print].

As Aedes aegypti continues to expand its global distribution, the diseases it vectors (dengue, Zika, chikungunya and yellow fever) are of increasing concern. Modern efforts to control this species include "rear and release" strategies where lab-reared mosquitoes are distributed throughout the landscape to replace or suppress invasive populations. These programs require intensive surveillance efforts to monitor their success, and the Biogents Sentinel (BGS) trap is one of the most effective tools for sampling adult Ae. aegypti. BGS trap catches can be highly variable throughout landscapes, so we investigated the potential impacts of environmental factors on adult Ae. aegypti capture rates during a "rear and release" program in California to better understand the relative contributions of true variability in population density across a landscape and trap context. We recorded male and female Ae. aegypti catches from BGS traps, with and without CO2, throughout control sites where no mosquitoes were released and in treatment sites where males infected with Wolbachia were released. BGS trap catches were positively influenced by higher proportions of shade or bushes in the front yard of the premises as well as the presence of potential larval habitats such as subterranean vaults. In contrast, an increase in residential habitat within a 100 m radius of trap locations negatively influenced BGS trap catches. For male Ae. aegypti, increased visual complexity of the trap location positively influenced capture rates, and the presence of yard drains negatively affected catch rates in control sites. Lastly, for BGS traps using CO2, higher catch rates were noted from traps placed greater than one meter from walls or fences for both male and female mosquitoes. These results have important implications for surveillance programs of Ae. aegypti throughout the Californian urban environment including adult monitoring during "rear and release" programs.

RevDate: 2020-06-12

Pina T, Sabater-Muñoz B, Cabedo-López M, et al (2020)

Molecular characterization of Cardinium, Rickettsia, Spiroplasma and Wolbachia in mite species from citrus orchards.

Experimental & applied acarology pii:10.1007/s10493-020-00508-z [Epub ahead of print].

Tetranychidae spider mites are considered key citrus pests in some production areas, especially Tetranychus urticae Koch. Over the past decades, pesticide overuse seems to have promoted T. urticae population selection in citrus orchards. However, the microbiota has also been pointed out as a plausible explanation for population structure or plant host specialisation observed in several arthropod species. In this work, we have determined the incidence of Cardinium, Rickettsia, Spiroplasma and Wolbachia as representatives of major distorter bacteria genera in Aplonobia histricina (Berlese), Eutetranychus banksi (McGregor), Eutetranychus orientalis (Klein), Panonychus citri (McGregor), Tetranychus evansi Baker and Pritchard, Tetranychus turkestani Ugarov and Nikolskii, and T. urticae populations from Spanish citrus orchards. Only Wolbachia was detected by PCR. The multilocus alignment approach and phylogenetic inference indicated that all detected Wolbachia belong to supergroup B. The deep analysis of each 16S rDNA, ftsZ and wsp gene sequences allowed identifying several phylogenetically different Wolbachia sequences. It probably indicates the presence of several different races or strains, all of them belonging to supergroup B. The wsp sequence typing analysis unveiled the presence of the two already identified alleles (61 and 370) and allowed to contribute with five new alleles, supporting the presence of different but related B-races in the studied mite populations. The results are discussed and related to T. urticae population structure, previously observed in Spanish citrus orchards.

RevDate: 2020-06-11

Madhav M, Brown G, Morgan JAT, et al (2020)

Transinfection of buffalo flies (Haematobia irritans exigua) with Wolbachia and effect on host biology.

Parasites & vectors, 13(1):296 pii:10.1186/s13071-020-04161-8.

BACKGROUND: Buffalo flies (Haematobia irritans exigua) (BF) and closely related horn flies (Haematobia irritans irritans) (HF) are invasive haematophagous parasites with significant economic and welfare impacts on cattle production. Wolbachia are intracellular bacteria found widely in insects and currently of much interest for use in novel strategies for the area wide control of insect pests and insect-vectored diseases. In this paper, we report the transinfection of BF towards the development of area-wide controls.

METHODS: Three stages of BF; embryos, pupae and adult female flies, were injected with different Wolbachia strains (wAlbB, wMel and wMelPop). The success of transinfection and infection dynamics was compared by real-time PCR and FISH and fitness effects were assessed in transinfected flies.

RESULTS: BF eggs were not easily injected because of their tough outer chorion and embryos were frequently damaged with less than 1% hatch rate of microinjected eggs. No Wolbachia infection was recorded in flies successfully reared from injected eggs. Adult and pupal injection resulted in higher survival rates and somatic and germinal tissue infections, with transmission to the succeeding generations on some occasions. Investigations of infection dynamics in flies from injected pupae confirmed that Wolbachia were actively multiplying in somatic tissues. Ovarian infections were confirmed with wMel and wMelPop in a number of instances, though not with wAlbB. Measurement of fitness traits indicated reduced longevity, decreased and delayed adult emergence, and reduced fecundity in Wolbachia-infected flies compared to mock-injected flies. Effects varied with the Wolbachia strain injected with most marked changes seen in the wMelPop-injected flies and least severe effects seen with wAlbB.

CONCLUSIONS: Adult and pupal injection were the most suitable methods for transinfecting BF and all three strains of Wolbachia successfully replicated in somatic tissues. The Wolbachia-induced fitness effects seen in transinfected BF suggest potential for use of the wMel or wMelPop strains in Wolbachia-based biocontrol programmes for BF.

RevDate: 2020-06-10

Cai T, Zhang Y, Liu Y, et al (2020)

Wolbachia enhances expression of NlCYP4CE1 in Nilaparvata lugens in response to imidacloprid stress.

Insect science [Epub ahead of print].

The brown planthopper, Nilaparvata lugens, is one of the main insect pests of rice. The N. lugens gene NlCYP4CE1 encodes cytochrome P450 monooxygenase (P450), which is a key enzyme in the metabolism of the insecticide imidacloprid. Previous research has suggested that the expression of NlCYP4CE1 is induced by imidacloprid stress, but the effect of bacterial symbionts on its expression has not been determined. The results of this study show that exposure to subtoxic imidacloprid changed the structure of the bacterial symbiont community in N. lugens. Specifically, the total bacterial content increased, but the bacterial species diversity decreased significantly. Wolbachia accounted for the largest proportion of bacteria in N. lugens; its abundance significantly increased after subtoxic imidacloprid exposure. The transcript level of NlCYP4CE1 was significantly increased by imidacloprid, but this effect was significantly weakened after Wolbachia was cleared with tetracycline. This result suggests that Wolbachia enhances the expression of NlCYP4CE1 to promote the detoxification metabolic response to imidacloprid stress. Understanding the effect of bacterial symbionts on gene expression in the host provides a new perspective on interactions between insecticides and their target insect pests, and highlights that subtoxic imidacloprid exposure may raise the risk of insecticide resistance by altering the structure of bacterial symbiont communities. This article is protected by copyright. All rights reserved.

RevDate: 2020-06-10

Zueva T, Morchón R, Carretón E, et al (2020)

Angiogenesis in cardiopulmonary dirofilariosis: does the Wolbachia surface protein have a pro- or anti-angiogenic effect?.

Journal of helminthology, 94:e162 pii:S0022149X20000450.

Cardiopulmonary dirofilariosis caused by Dirofilaria immitis produces inflammation, blood vessel obstruction and hypoxia, which are required conditions for the beginning of the process of neovascularization. Since D. immitis harbours intracellular symbiotic Wolbachia bacterium, the global understanding of the angiogenic process requires the analysis of the effect of the parasite molecules, but also that of Wolbachia. Canine primary lung microvascular endothelial cells were treated with the recombinant Wolbachia surface protein (rWSP) and the expression of angiogenic factors like Vascular Endothelial Growth Factor-A (VEGF-A), sFlt, membrane Endoglin (mEndoglin) and soluble Endoglin (sEndoglin), as well as the in vitro formation of pseudocapillaries, were measured. The analyses showed a significant increase in the expression of pro-angiogenic VEGF-A and anti-angiogenic sEndoglin, together with a significant decrease in both pro-angiogenic mEndoglin and pseudocapillary formation, compared to untreated controls. Due to the complexity of the angiogenic process and its relationship with other physiological processes like inflammation and fibrinolysis, these results might suggest that rWSP participate in various mechanisms related to each other and its effects might depend either on the balance between them or on the moment of their occurrence.

RevDate: 2020-06-10

Torres-Monzón JA, Casas-Martínez M, T López-Ordóñez (2020)

Infection of Aedes mosquitoes by native Wolbachia in urban cemeteries of Southern Mexico.

Salud publica de Mexico [Epub ahead of print].

OBJECTIVE: To evaluate the prevalence of Wolbachia infections in Aedes spp. field populations from cemeteries of Southern Mexico.

MATERIALS AND METHODS: Six cemeteries were selected to be sampled in the central part of the Soconusco region, Chiapas. Aedes albopictus and Ae. aegypti mosquitoes were collected during the rainy season of 2015. Females were analyzed individually by PCR to determine the presence of Wolbachia.

RESULTS: A field overall prevalence of 38% was found; only Ae. albopictus mosquitoes were positive.

CONCLUSIONS: Local strains of Wolbachia were detected and have the potential to be applied as a biological method for vector control.

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RJR Experience and Expertise

Researcher

Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.

Educator

Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.

Administrator

Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.

Technologist

Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.

Publisher

While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.

Speaker

Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.

Facilitator

Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.

Designer

Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

short personal version

Curriculum Vitae for R J Robbins

long standard version

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