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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 26 Jun 2019 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®)

RevDate: 2019-06-24

Hinojosa JC, Koubínová D, Szenteczki M, et al (2019)

A mirage of cryptic species: genomics uncover striking mito-nuclear discordance in the butterfly Thymelicus sylvestris.

Molecular ecology [Epub ahead of print].

Mitochondrial DNA (mtDNA) sequencing has led to an unprecedented rise in the identification of cryptic species. However, it is widely acknowledged that nuclear DNA (nuDNA) sequence data are also necessary to properly define species boundaries. Next generation sequencing techniques provide a wealth of nuclear genomic data, which can be used to ascertain both the evolutionary history and taxonomic status of putative cryptic species. Here, we focus on the intriguing case of the butterfly Thymelicus sylvestris (Lepidoptera: Hesperiidae). We identified six deeply diverged mitochondrial lineages; three distributed all across Europe and found in sympatry, suggesting a potential case of cryptic species. We then sequenced these six lineages using double-digest restriction-site associated DNA sequencing (ddRADseq). Nuclear genomic loci contradicted mtDNA patterns and genotypes generally clustered according to geography, i.e., a pattern expected under the assumption of postglacial recolonization from different refugia. Further analyses indicated that this strong mtDNA/nuDNA discrepancy cannot be explained by incomplete lineage sorting, sex-biased asymmetries, NUMTs, natural selection, introgression or Wolbachia-mediated genetic sweeps. We suggest that this mito-nuclear discordance was caused by long periods of geographic isolation followed by range expansions, homogenizing the nuclear but not the mitochondrial genome. These results highlight T. sylvestris as a potential case of multiple despeciation and/or lineage fusion events. We finally argue, since mtDNA and nuDNA do not necessarily follow the same mechanisms of evolution, their respective evolutionary history reflects complementary aspects of past demographic and biogeographic events. This article is protected by copyright. All rights reserved.

RevDate: 2019-06-23

Ammini P, Vijayan J, Krishna AV, et al (2019)

Dominance of Wolbachia sp. in the deep-sea sediment bacterial metataxonomic sequencing analysis in the Bay of Bengal, Indian Ocean.

Genomics pii:S0888-7543(18)30676-1 [Epub ahead of print].

The Bay of Bengal, located in the north-eastern part of the Indian Ocean is world's largest bay occupying an area of ~8,39,000 mile2. The variability in bacterial community structure and function in sediment ecosystems of the Bay of Bengal is examined by Illumina high-throughput metagenomic sequencing. Of five metataxonomics data sets presented, two (SD1 and SD2) were from stations close to the shore and three (SD4, SD5, and SD6) were from the deep-sea (~3000 m depth). Phylum Proteobacteria (90.27 to 92.52%) dominated the deep-sea samples, whereas phylum Firmicutes (65.35 to 90.98%) dominated the coastal samples. Comparative analysis showed that coastal and deep-sea sediments showed distinct microbial communities. Wolbachia species, belonging to class Alphaproteobacteria was the most dominant species in the deep-sea sediments. The gene functions of bacterial communities were predicted for deep-sea and coastal sediment ecosystems. The results indicated that deep-sea sediment bacterial communities were involved in metabolic activities like dehalogenation and sulphide oxidation.

RevDate: 2019-06-23

Bock W, Y Jayathunga (2019)

Optimal control of a Multi-patch Dengue Model under the Influence of Wolbachia Bacterium.

Mathematical biosciences pii:S0025-5564(18)30309-2 [Epub ahead of print].

In this work, a multi-patch model for dengue transmission dynamics including the bacterium Wolbachia is studied and by that the control efforts to minimize the disease spread by host and vector control are investigated. The multi-patch system models the host movement within the patches which coupled via a residence-time budgeting matrix P. Numerical results confirm that the control mechanism embedded in incidence rates of the disease transmission, effectively reduce the spread of the disease.

RevDate: 2019-06-22

Cooper BS, Vanderpool D, Conner WR, et al (2019)

Wolbachia Acquisition by Drosophila yakuba-clade Hosts and Transfer of Incompatibility Loci Between Distantly Related Wolbachia.

Genetics pii:genetics.119.302349 [Epub ahead of print].

Maternally transmitted Wolbachia infect about half of insect species, yet the predominant mode(s) of Wolbachia acquisition remains uncertain. Species-specific associations could be old, with Wolbachia and hosts co-diversifying (i.e., cladogenic acquisition), or relatively young and acquired by horizontal transfer or introgression. The three Drosophila yakuba-clade hosts ((D. santomea, D. yakuba), D. teissieri) diverged about three million years ago and currently hybridize on Bioko and São Tomé, west African islands. Each species is polymorphic for nearly identical Wolbachia that cause weak cytoplasmic incompatibility (CI)-reduced egg hatch when uninfected females mate with infected males. D. yakuba-clade Wolbachia are closely related to wMel, globally polymorphic in D. melanogaster We use draft Wolbachia and mitochondrial genomes to demonstrate that D. yakuba-clade phylogenies for Wolbachia and mitochondria tend to follow host nuclear phylogenies. However, roughly half of D. santomea individuals, sampled both inside and outside of the São Tomé hybrid zone, have introgressed D. yakuba mitochondria. Both mitochondria and Wolbachia possess far more recent common ancestors than the bulk of the host nuclear genomes, precluding cladogenic Wolbachia acquisition. General concordance of Wolbachia and mitochondrial phylogenies suggests that horizontal transmission is rare, but varying relative rates of molecular divergence complicate chronogram-based statistical tests. Loci that cause CI in wMel are disrupted in D. yakuba-clade Wolbachia; but, a second set of loci predicted to cause CI are located in the same WO prophage region. These alternative CI loci seem to have been acquired horizontally from distantly related Wolbachia, with transfer mediated by flanking Wolbachia-specific ISWpi1 transposons.

RevDate: 2019-06-21

Mateos M, Silva NO, Ramirez P, et al (2019)

Effect of heritable symbionts on maternally-derived embryo transcripts.

Scientific reports, 9(1):8847 pii:10.1038/s41598-019-45371-0.

Maternally-transmitted endosymbiotic bacteria are ubiquitous in insects. Among other influential phenotypes, many heritable symbionts of arthropods are notorious for manipulating host reproduction through one of four reproductive syndromes, which are generally exerted during early developmental stages of the host: male feminization; parthenogenesis induction; male killing; and cytoplasmic incompatibility (CI). Major advances have been achieved in understanding mechanisms and identifying symbiont factors involved in reproductive manipulation, particularly male killing and cytoplasmic incompatibility. Nonetheless, whether cytoplasmically-transmitted bacteria influence the maternally-loaded components of the egg or early embryo has not been examined. In the present study, we investigated whether heritable endosymbionts that cause different reproductive phenotypes in Drosophila melanogaster influence the mRNA transcriptome of early embryos. We used mRNA-seq to evaluate differential expression in Drosophila embryos lacking endosymbionts (control) to those harbouring the male-killing Spiroplasma poulsonii strain MSRO-Br, the CI-inducing Wolbachia strain wMel, or Spiroplasma poulsonii strain Hyd1; a strain that lacks a reproductive phenotype and is naturally associated with Drosophila hydei. We found no consistent evidence of influence of symbiont on mRNA composition of early embryos, suggesting that the reproductive manipulation mechanism does not involve alteration of maternally-loaded transcripts. In addition, we capitalized on several available mRNA-seq datasets derived from Spiroplasma-infected Drosophila melanogaster embryos, to search for signals of depurination of rRNA, consistent with the activity of Ribosome Inactivating Proteins (RIPs) encoded by Spiroplasma poulsonii. We found small but statistically significant signals of depurination of Drosophila rRNA in the Spiroplasma treatments (both strains), but not in the symbiont-free control or Wolbachia treatment, consistent with the action of RIPs. The depurination signal was slightly stronger in the treatment with the male-killing strain. This result supports a recent report that RIP-induced damage contributes to male embryo death.

RevDate: 2019-06-19

Su QC, Wang X, Deng C, et al (2019)

Transcriptome responses to elevated CO2 level and Wolbachia-infection stress in Hylyphantes graminicola (Araneae: Linyphiidae).

Insect science [Epub ahead of print].

Hylyphantes graminicola is a resident spider species found in maize and cotton fields and is an important biological control agent of various pests. Previous studies have demonstrated that stress from elevated CO2 and Wolbachia infection can strongly affect spider species. Thus, based on CO2 levels (400 ppm, current atmospheric CO2 concentration and 800 ppm, high CO2 concentration) and Wolbachia status (Wolbachia-infected, W+ and Wolbachia-uninfected, W-), we divided H. graminicola individuals into four treatment groups: i.e., W- 400 ppm, W- 800 ppm, W+ 400 ppm, and W+ 800 ppm. To investigate the effects of elevated CO2 levels (W- 400 vs W- 800), Wolbachia-infection (W- 400 vs W+ 400), and the interactions between these two factors (W- 400 vs W+ 800), high-throughput transcriptome sequencing was employed to characterize the de novo transcriptome of the spiders and identify stress-related differentially expressed genes (DEGs). De novo assembly of cDNA sequences generated 86 688 unigenes, 23 938 of which were annotated in public databases. A total of 84, 21, and 157 DEGs were found among W- 400 vs W- 800, W- 400 vs W+ 400, and W- 400 vs W+ 800, respectively. Functional enrichment analysis revealed that metabolic processes, signaling, and catalytic activity were significantly affected by elevated CO2 levels and Wolbachia infection. Our findings suggest that the impact of elevated CO2 levels and Wolbachia infection on the H. graminicola transcriptome was, to a large extent, on genes involved in metabolic processes. This study is the first description of transcriptome changes in response to elevated CO2 levels and Wolbachia infection in spiders. This article is protected by copyright. All rights reserved.

RevDate: 2019-06-19

Konecka E, Z Olszanowski (2019)

First Evidence of Intracellular Bacteria Cardinium in Thermophilic Mite Microzetorchestes emeryi (Acari: Oribatida): Molecular Screening of Bacterial Endosymbiont Species.

Current microbiology pii:10.1007/s00284-019-01717-5 [Epub ahead of print].

We undertook the issue of the distribution of intracellular bacteria among Oribatida (Acari). Six genera of bacteria were detected by PCR and Sanger DNA sequencing: Wolbachia, Cardinium, Rickettsia, Spiroplasma, Arsenophonus, and Hamiltonella. Our research, for the first time, revealed the presence of Cardinium in Microzetorchestes emeryi in two subpopulations separated from each other by 300 m. The percentages of infected animals were the same in both subpopulations-ca. 20%. The identity of 16S rDNA sequences of Cardinium between these two subpopulations of M. emeryi was 97%. Phylogenetic analysis showed that the Cardinium in M. emeryi was clustered into the group A. The occurrence of M. emeryi in Poland has not been reported before and our report is the first one. Cardinium maybe help the thermophilic M. emeryi to adapt to low temperatures in the Central Europe.

RevDate: 2019-06-18

Schebeck M, Feldkirchner L, Stauffer C, et al (2019)

Dynamics of an Ongoing Wolbachia Spread in the European Cherry Fruit Fly, Rhagoletis cerasi (Diptera: Tephritidae).

Insects, 10(6): pii:insects10060172.

Numerous terrestrial arthropods are infected with the alphaproteobacterium Wolbachia. This endosymbiont is usually transmitted vertically from infected females to their offspring and can alter the reproduction of hosts through various manipulations, like cytoplasmic incompatibility (CI), enhancing its spread in new host populations. Studies on the spatial and temporal dynamics of Wolbachia under natural conditions are scarce. Here, we analyzed Wolbachia infection frequencies in populations of the European cherry fruit fly, Rhagoletis cerasi (L.), in central Germany-an area of an ongoing spread of the CI-inducing strain wCer2. In total, 295 individuals from 19 populations were PCR-screened for the presence of wCer2 and their mitochondrial haplotype. Results were compared with historic data to understand the infection dynamics of the ongoing wCer2 invasion. An overall wCer2 infection frequency of about 30% was found, ranging from 0% to 100% per population. In contrast to an expected smooth transition from wCer2-infected to completely wCer2-uninfected populations, a relatively scattered infection pattern across geography was observed. Moreover, a strong Wolbachia-haplotype association was detected, with only a few rare misassociations. Our results show a complex dynamic of an ongoing Wolbachia spread in natural field populations of R. cerasi.

RevDate: 2019-06-17

Watanabe A, Takaku S, Yokota K, et al (2019)

A survey of Lasioderma serricorne (Fabricius) in Japanese Dental Clinics.

Biocontrol science, 24(2):117-121.

This study was to survey the capturing rate in Japanese dental clinics of the Lasioderma serricorne (cigarette beetles) , and to evaluate the beetle's potential as a carrier for transmission of nosocomial pathogens. L. serricorne imagoes were captured in pheromone traps in 14 Japanese dental clinics in August and September 2012 and 2013, and their numbers recorded. Polymerase chain reaction (PCR) for the bacterial antibiotic-resistant genes mecA, vanA, vanB, blaIMP, and blaVIM was performed on the captured L. serricorne imagoes. Bacterial species in the captured specimens were identified by 16S rRNA PCR and sequencing analysis. The L. serricorne imagoes were captured from 10 dental clinics (71.4%) . We failed to detect the presence of nosocomial antibiotic-resistant pathogens in L. serricorne imagoes. The bacterial species detected most commonly in the imagoes was Wolbachia sp., an intracellular proteobacterium infecting certain insect species. Monitoring of insects including L. serricorne should be incorporated into regiment of the infection control.

RevDate: 2019-06-17
CmpDate: 2019-06-17

Shaw WR, F Catteruccia (2019)

Vector biology meets disease control: using basic research to fight vector-borne diseases.

Nature microbiology, 4(1):20-34.

Human pathogens that are transmitted by insects are a global problem, particularly those vectored by mosquitoes; for example, malaria parasites transmitted by Anopheles species, and viruses such as dengue, Zika and chikungunya that are carried by Aedes mosquitoes. Over the past 15 years, the prevalence of malaria has been substantially reduced and virus outbreaks have been contained by controlling mosquito vectors using insecticide-based approaches. However, disease control is now threatened by alarming rates of insecticide resistance in insect populations, prompting the need to develop a new generation of specific strategies that can reduce vector-mediated transmission. Here, we review how increased knowledge in insect biology and insect-pathogen interactions is stimulating new concepts and tools for vector control. We focus on strategies that either interfere with the development of pathogens within their vectors or directly impact insect survival, including enhancement of vector-mediated immune control, manipulation of the insect microbiome, or use of powerful new genetic tools such as CRISPR-Cas systems to edit vector genomes. Finally, we offer a perspective on the implementation hurdles as well as the knowledge gaps that must be filled in the coming years to safely realize the potential of these novel strategies to eliminate the scourge of vector-borne disease.

RevDate: 2019-06-13

Ant TH, Herd C, Louis F, et al (2019)

Wolbachia transinfections in Culex quinquefasciatus generate cytoplasmic incompatibility.

Insect molecular biology [Epub ahead of print].

Culex quinquefasciatus is an important mosquito vector of a number of viral and protozoan pathogens of humans and animals, and naturally carries the endosymbiont Wolbachia pipientis, strain wPip. Wolbachia are being used in two distinct vector control strategies: firstly, population suppression caused by mating incompatibilities between mass-released transinfected males and wild females; and secondly, the spread of pathogen transmission-blocking strains through populations. Using embryonic microinjection, two novel Wolbachia transinfections were generated in Cx. quinquefasciatus using strains native to the mosquito Aedes albopictus: a wAlbB single infection, and a wPip plus wAlbA superinfection. The wAlbB infection showed full bi-directional cytoplasmic incompatibility (CI) with wild-type Cx. quinquefasciatus in reciprocal crosses. The wPipwAlbA superinfection showed complete unidirectional CI, and therefore population invasion potential. While the wAlbB strain showed comparatively low overall densities, similar to the native wPip, the wPipwAlbA superinfection reached over 400-fold higher densities in the salivary glands compared to the native wPip, suggesting it may be a candidate for pathogen transmission blocking. This article is protected by copyright. All rights reserved.

RevDate: 2019-06-13

Koh C, Audsley MD, Di Giallonardo F, et al (2019)

Sustained Wolbachia-mediated blocking of dengue virus isolates following serial passage in Aedes aegypti cell culture.

Virus evolution, 5(1):vez012 pii:vez012.

Wolbachia is an intracellular endosymbiont of insects that inhibits the replication of a range of pathogens in its arthropod hosts. The release of Wolbachia into wild populations of mosquitoes is an innovative biocontrol effort to suppress the transmission of arthropod-borne viruses (arboviruses) to humans, most notably dengue virus. The success of the Wolbachia-based approach hinges upon the stable persistence of the 'pathogen blocking' effect, whose mechanistic basis is poorly understood. Evidence suggests that Wolbachia may affect viral replication via a combination of competition for host resources and activation of host immunity. The evolution of resistance against Wolbachia and pathogen blocking in the mosquito or the virus could reduce the public health impact of the symbiont releases. Here, we investigate if dengue 3 virus (DENV-3) is capable of accumulating adaptive mutations that improve its replicative capacity during serial passage in Wolbachia wMel-infected cells. During the passaging regime, viral isolates in Wolbachia-infected cells exhibited greater variation in viral loads compared to controls. The viral loads of these isolates declined rapidly during passaging due to the blocking effects of Wolbachia carriage, with several being lost all together and the remainder recovering to low but stable levels. We attempted to sequence the genomes of the surviving passaged isolates but, given their low abundance, were unable to obtain sufficient depth of coverage for evolutionary analysis. In contrast, viral loads in Wolbachia-free control cells were consistently high during passaging. The surviving isolates passaged in the presence of Wolbachia exhibited a reduced ability to replicate even in Wolbachia-free cells. These experiments demonstrate the challenge for dengue in evolving resistance to Wolbachia-mediated blocking.

RevDate: 2019-06-12

Chrostek E, M Gerth (2019)

Is Anopheles gambiae a Natural Host of Wolbachia?.

mBio, 10(3): pii:mBio.00784-19.

Wolbachia (Alphaproteobacteria, Rickettsiales) is an intraovarially transmitted symbiont of insects able to exert striking phenotypes, including reproductive manipulations and pathogen blocking. These phenotypes make Wolbachia a promising tool to combat mosquito-borne diseases. Although Wolbachia is present in the majority of terrestrial arthropods, including many disease vectors, it was considered absent from Anopheles gambiae mosquitos, the main vectors of malaria in sub-Saharan Africa. In 2014, Wolbachia sequences were detected in A. gambiae samples collected in Burkina Faso. Subsequently, similar evidence came from collections all over Africa, revealing a high Wolbachia 16S rRNA sequence diversity, low abundance, and a lack of congruence between host and symbiont phylogenies. Here, we reanalyze and discuss recent evidence on the presence of Wolbachia sequences in A. gambiae. We find that although detected at increasing frequencies, the unusual properties of these Wolbachia sequences render them insufficient to diagnose natural infections in A. gambiae Future studies should focus on uncovering the origin of Wolbachia sequence variants in Anopheles and seeking sequence-independent evidence for this new symbiosis. Understanding the ecology of Anopheles mosquitos and their interactions with Wolbachia will be key in designing successful, integrative approaches to limit malaria spread. Although the prospect of using Wolbachia to fight malaria is intriguing, the newly discovered strains do not bring it closer to realization.IMPORTANCEAnopheles gambiae mosquitos are the main vectors of malaria, threatening around half of the world's population. The bacterial symbiont Wolbachia can interfere with disease transmission by other important insect vectors, but until recently, it was thought to be absent from natural A. gambiae populations. Here, we critically analyze the genomic, metagenomic, PCR, imaging, and phenotypic data presented in support of the presence of natural Wolbachia infections in A. gambiae We find that they are insufficient to diagnose Wolbachia infections and argue for the need of obtaining robust data confirming basic Wolbachia characteristics in this system. Determining the Wolbachia infection status of Anopheles is critical due to its potential to influence Anopheles population structure and Plasmodium transmission.

RevDate: 2019-06-08

Baião GC, Schneider DI, Miller WJ, et al (2019)

The effect of Wolbachia on gene expression in Drosophila paulistorum and its implications for symbiont-induced host speciation.

BMC genomics, 20(1):465 pii:10.1186/s12864-019-5816-9.

BACKGROUND: The Neotropical fruit fly Drosophila paulistorum (Diptera: Drosophilidae) is a species complex in statu nascendi comprising six reproductively isolated semispecies, each harboring mutualistic Wolbachia strains. Although wild type flies of each semispecies are isolated from the others by both pre- and postmating incompatibilities, mating between semispecies and successful offspring development can be achieved once flies are treated with antibiotics to reduce Wolbachia titer. Here we use RNA-seq to study the impact of Wolbachia on D. paulistorum and investigate the hypothesis that the symbiont may play a role in host speciation. For that goal, we analyze samples of heads and abdomens of both sexes of the Amazonian, Centro American and Orinocan semispecies of D. paulistorum.

RESULTS: We identify between 175 and 1192 differentially expressed genes associated with a variety of biological processes that respond either globally or according to tissue, sex or condition in the three semispecies. Some of the functions associated with differentially expressed genes are known to be affected by Wolbachia in other species, such as metabolism and immunity, whereas others represent putative novel phenotypes involving muscular functions, pheromone signaling, and visual perception.

CONCLUSIONS: Our results show that Wolbachia affect a large number of biological functions in D. paulistorum, particularly when present in high titer. We suggest that the significant metabolic impact of the infection on the host may cause several of the other putative and observed phenotypes. We also speculate that the observed differential expression of genes associated with chemical communication and reproduction may be associated with the emergence of pre- and postmating barriers between semispecies, which supports a role for Wolbachia in the speciation of D. paulistorum.

RevDate: 2019-06-07

Xie K, Lu YJ, Yang K, et al (2019)

Co-infection of Wolbachia and Spiroplasma in spider mite Tetranychus truncatus increases male fitness.

Insect science [Epub ahead of print].

Wolbachia and Spiroplasma are intracellular bacteria that are of great interest to entomologists, because of their ability to alter insect host biology in multiple ways. In the spider mite Tetranychus truncatus, co-infection of Wolbachia and Spiroplasma can induce cytoplasmic incompatibility (CI) and fitness costs; however, little is known about the effect of co-infection at the genetic level and the molecular mechanisms underlying CI. In this study, we explored the influence of the two symbionts on male mite host fitness and used RNA-Seq to generate the transcriptomes of T. truncatus with four different types of infection. In total, we found that symbiont-infected lines had a higher hatch proportion than the uninfected line, and the development time of the uninfected line was longer than that of the other lines. Co-infection changed the expression of many genes related to digestion detoxification, reproduction, immunity and oxidation reduction. Our results indicate that co-infection of Wolbachia and Spiroplasma confers multiple effects on their hosts, and help illuminate the complex interactions between endosymbionts and arthropods. This article is protected by copyright. All rights reserved.

RevDate: 2019-06-06

Bonning BC (2019)

The Insect Virome: Opportunities and Challenges.

Current issues in molecular biology, 34:1-12 pii:v34/1 [Epub ahead of print].

The insect virome is composed of a myriad of viruses. Both field populations and laboratory colonies of insects harbour diverse viruses, including viruses that infect the insect itself, viruses of microbes associated with the insect, and viruses associated with ingested materials. Metagenomics analysis for identification of virus-derived sequences has allowed for new appreciation of the extent and diversity of the insect virome. The complex interactions between insect viruses and host antiviral immune pathways (RNA interference and apoptosis), and between viruses and other members of the microbiome (e.g. Wolbachia) are becoming apparent. In this chapter, an overview of the diversity of viruses in insects and recent virus discovery research for specific insects and insect-derived cell lines is provided. The opportunities and challenges associated with the insect virome, including the potential impacts of viruses on both research and insect management programs are also addressed.

RevDate: 2019-06-04

Batsa Debrah L, Phillips RO, Pfarr K, et al (2019)

The Efficacy of Doxycycline Treatment on Mansonella perstans Infection: An Open-Label, Randomized Trial in Ghana.

The American journal of tropical medicine and hygiene [Epub ahead of print].

Treating Mansonella perstans is challenged by the low efficacy of registered antihelminthics. Wolbachia endobacteria provide an alternative treatment target because depletion results in amicrofilaremia in filarial infections with Wuchereria bancrofti and Onchocerca volvulus infections. This open-label, randomized study sought to confirm that i) Wolbachia are present in M. perstans in Ghana and ii) doxycycline treatment will deplete Wolbachia and cause a slow, sustained decline in microfilariae (MF). Two hundred and two Ghanaians with M. perstans infection were randomized into early (immediate) and delayed (6 months deferred) treatment groups, given doxycycline 200 mg/day for 6 weeks, and monitored for MF and Wolbachia levels at baseline, 4, 12, and 24 months after the study onset (= time of randomization and start of treatment for the early group). Per protocol analysis revealed that the median MF/mL in the early group declined from 138 at baseline to 64 at month 4 and further to 0 at month 12. In the delayed group, MF load did not change from a baseline median of 97 to 102 at month 4 but declined to 42 at month 12, that is, 6 months after receiving treatment, trailing the early group as expected. By month 24, both treatment groups had reached a median MF level of 0. After treatment, Wolbachia were depleted from MF by ≥ 1-log drop compared with baseline levels. We conclude that M. perstans in Ghana harbor Wolbachia that are effectively depleted by doxycycline with subsequent reduction in MF loads, most likely because of interruption of fertility of adult worms.

RevDate: 2019-06-10

Kulkarni A, Yu W, Jiang J, et al (2019)

Wolbachia pipientis occurs in Aedes aegypti populations in New Mexico and Florida, USA.

Ecology and evolution, 9(10):6148-6156 pii:ECE35198.

The mosquitoes Aedes aegypti (L.) and Ae. albopictus Skuse are the major vectors of dengue, Zika, yellow fever, and chikungunya viruses worldwide. Wolbachia, an endosymbiotic bacterium present in many insects, is being utilized in novel vector control strategies to manipulate mosquito life history and vector competence to curb virus transmission. Earlier studies have found that Wolbachia is commonly detected in Ae. albopictus but rarely detected in Ae. aegypti. In this study, we used a two-step PCR assay to detect Wolbachia in wild-collected samples of Ae. aegypti. The PCR products were sequenced to validate amplicons and identify Wolbachia strains. A loop-mediated isothermal amplification (LAMP) assay was developed and used for detecting Wolbachia in selected mosquito specimens as well. We found Wolbachia in 85/148 (57.4%) wild Ae. aegypti specimens from various cities in New Mexico, and in 2/46 (4.3%) from St. Augustine, Florida. Wolbachia was not detected in 94 samples of Ae. aegypti from Deer Park, Harris County, Texas. Wolbachia detected in Ae. aegypti from both New Mexico and Florida was the wAlbB strain of Wolbachia pipientis. A Wolbachia-positive colony of Ae. aegypti was established from pupae collected in Las Cruces, New Mexico, in 2018. The infected females of this strain transmitted Wolbachia to their progeny when crossed with males of Rockefeller strain of Ae. aegypti, which does not carry Wolbachia. In contrast, none of the progeny of Las Cruces males mated to Rockefeller females were infected with Wolbachia.

RevDate: 2019-06-04

Gichuhi J, Khamis FM, Van den Berg J, et al (2019)

Unexpected Diversity of Wolbachia Associated with Bactrocera dorsalis (Diptera: Tephritidae) in Africa.

Insects, 10(6): pii:insects10060155.

Bactrocera dorsalis (Hendel) is an important pest of fruit-bearing plants in many countries worldwide. In Africa, this pest has spread rapidly and has become widely established since the first invasion report in 2003. Wolbachia is a vertically transmitted endosymbiont that can significantly influence aspects of the biology and, in particular, the reproduction of its host. In this study, we screened B. dorsalis specimens collected from several locations in Africa between 2005 and 2017 for Wolbachia using a PCR-based assay to target the Wolbachia surface protein wsp. Of the 357 individuals tested, 10 were positive for Wolbachia using the wsp assay. We identified four strains of Wolbachia infecting two B. dorsalis mitochondrial haplotypes. We found no strict association between the infecting strain and host haplotype, with one strain being present in two different host haplotypes. All the detected strains belonged to Super Group B Wolbachia and did not match any strains reported previously in B. dorsalis in Asia. These findings indicate that diverse Wolbachia infections are present in invasive populations of B. dorsalis.

RevDate: 2019-06-10

Yashiro T, N Lo (2019)

Comparative screening of endosymbiotic bacteria associated with the asexual and sexual lineages of the termite Glyptotermes nakajimai.

Communicative & integrative biology, 12(1):55-58 pii:1592418.

Males provide opportunities both for sexual reproduction and for sex-based phenotypic differences within animal societies. In termites, the ubiquitous presence of both male and female workers and soldiers indicate that males play a critical role in colonies of these insects. However, we have recently reported all-female asexual societies in a lineage of the termite Glyptotermes nakajimai - a dramatic transition from mixed-sex to all-female asexual societies. It is known that female-producing parthenogenesis in insects can be induced by maternally inherited endosymbiotic bacteria, such as Wolbachia, Cardinium, and Rickettsia. Here, we screen for the presence of endosymbiotic bacteria in the asexual and sexual lineages of G. nakajimai. Our bacterial screening of the asexual lineage did not reveal any likely causal agents for parthenogenetic reproduction, whereas screening of the sexual lineage resulted in Wolbachia being detected. Our findings suggest that the asexuality in G. nakajimai is likely to be maintained without manipulation by endosymbiotic bacteria.

RevDate: 2019-06-10

Wasala SK, Brown AMV, Kang J, et al (2019)

Variable Abundance and Distribution of Wolbachia and Cardinium Endosymbionts in Plant-Parasitic Nematode Field Populations.

Frontiers in microbiology, 10:964.

The bacterial endosymbiont Wolbachia interacts with different invertebrate hosts, engaging in diverse symbiotic relationships. Wolbachia is often a reproductive parasite in arthropods, but an obligate mutualist in filarial nematodes. Wolbachia was recently discovered in plant-parasitic nematodes, and, is thus far known in just two genera Pratylenchus and Radopholus, yet the symbiont's function remains unknown. The occurrence of Wolbachia in these economically important plant pests offers an unexplored biocontrol strategy. However, development of Wolbachia-based biocontrol requires an improved understanding of symbiont-host functional interactions and the symbiont's prevalence among nematode field populations. This study used a molecular-genetic approach to assess the prevalence of a Wolbachia lineage (wPpe) in 32 field populations of Pratylenchus penetrans. Populations were examined from eight different plant species in Washington, Oregon, and California. Nematodes were also screened for the endosymbiotic bacterium Cardinium (cPpe) that was recently shown to co-infect P. penetrans. Results identified wPpe in 9/32 and cPpe in 1/32 of P. penetrans field populations analyzed. No co-infection was observed in field populations. Wolbachia was detected in nematodes from 4/8 plant-hosts examined (raspberry, strawberry, clover, and lily), and in all three states surveyed. Cardinium was detected in nematodes from mint in Washington. In the wPpe-infected P. penetrans populations collected from raspberry, the prevalence of wPpe infection ranged from 11 to 58%. This pattern is unlike that in filarial nematodes where Wolbachia is an obligate mutualist and occurs in 100% of the host. Further analysis of wPpe-infected populations revealed female-skewed sex ratios (up to 96%), with the degree of skew positively correlating with wPpe prevalence. Uninfected nematode populations had approximately equal numbers of males and females. Comparisons of 54 wPpe 16S ribosomal RNA sequences revealed high similarity across the geographic isolates, with 45 of 54 isolates being identical at this locus. The complete absence of wPpe among some populations and low prevalence in others suggest that this endosymbiont is not an obligate mutualist of P. penetrans. The observed sex ratio bias in wPpe-infected nematode populations is similar to that observed in arthropods where Wolbachia acts as a reproductive manipulator, raising the question of a similar role in plant-parasitic nematodes.

RevDate: 2019-06-04

Guo Y, Gong JT, Mo PW, et al (2019)

Wolbachia localization during Laodelphax striatellus embryogenesis.

Journal of insect physiology, 116:125-133.

Wolbachia are intracellular bacteria carried by thousands of arthropod species. The success of Wolbachia is due to efficient vertical transmission by the host maternal germline. Wolbachia's behavior during host oogenesis is well characterized, although their behavior during embryogenesis is unclear. Vertical transmission of Wolbachia wStri in the small brown planthopper, Laodelphax striatellus is extraordinarily efficient. To understand why, we investigated its localization and dynamics in L. striatellus embryos. Microscopic observations indicated that the Wolbachia were mainly localized at the anterior region of the embryo during early embryogenesis. The distribution of Wolbachia within the anterior region was established during oogenesis, and according to a phylogenetic analysis, may be due to intrinsic factors in Wolbachia. We observed that wStri migrated to the posterior part cells during late embryogenesis, in the region where gonads were formed. An expression profile of Wolbachia-infected host embryonic development genes revealed Ddx1 mRNAs, which is required for host viability and in the germ line, accumulated in the posterior region of 3-day-old embryos, while other development genes mRNAs were significantly more abundant in the posterior region of 6-day-old embryos. These genes thus appear to be associated with the localization of Wolbachia wStri in the anterior region, although their functions remain unclear. These results can explain Wolbachia wStri high prevalence in L. striatellus.

RevDate: 2019-05-23

Hubert J, Nesvorna M, Klimov P, et al (2019)

Differential allergen expression in three Tyrophagus putrescentiae strains inhabited by distinct microbiome.

RevDate: 2019-05-23

Chouin-Carneiro T, Ant TH, Herd C, et al (2019)

Wolbachia strain wAlbA blocks Zika virus transmission in Aedes aegypti.

Medical and veterinary entomology [Epub ahead of print].

Transinfections of the maternally transmitted endosymbiont Wolbachia pipientis can reduce RNA virus replication and prevent transmission by Aedes aegypti, and also have the capacity to invade wild-type populations, potentially reaching and maintaining high infection frequencies. Levels of virus transmission blocking are positively correlated with Wolbachia intracellular density. Despite reaching high densities in Ae. aegypti, transinfections of wAlbA, a strain native to Aedes albopictus, showed no blocking of Semliki Forest Virus in previous intrathoracic injection challenges. To further characterize wAlbA blocking in Ae. aegypti, adult females were intrathoracically challenged with Zika (ZIKV) and dengue viruses, and then fed a ZIKV-containing bloodmeal. No blocking was observed with either virus when challenged by intrathoracic injection. However, when ZIKV was delivered orally, wAlbA-infected females showed a significant reduction in viral replication and dissemination compared with uninfected controls, as well as a complete absence of virus in saliva. Although other Wolbachia strains have been shown to cause more robust viral blocking in Ae. aegypti, these findings demonstrate that, in principle, wAlbA could be used to reduce virus transmission in this species. Moreover, the results highlight the potential for underestimation of the strength of virus-blocking when based on intrathoracic injection compared with more natural oral challenges.

RevDate: 2019-06-10
CmpDate: 2019-05-31

Gómez-Díaz JS, Montoya-Lerma J, V Muñoz Valencia (2019)

Prevalence and Diversity of Endosymbionts in Cassava Whiteflies (Hemiptera: Aleyrodidae) From Colombia.

Journal of insect science (Online), 19(3):.

Whiteflies cause huge economic losses for cassava (Manihot esculenta Crantz) cultivation. Damage can be caused directly when the insects feed on the phloem and/or indirectly by the transmission of viruses. It has been found that whiteflies maintain a close relationship with some endosymbiotic bacteria and that this interaction produces different effects on host biology and can also facilitate viral transmission. This study aimed to characterize the diversity of secondary endosymbionts (SE) present in whiteflies associated with cassava. Whitefly adults and nymphs were collected from cassava crops at nine locations in Southwestern Colombia. Molecular identification of insects and endosymbionts was carried out using specific mtCOI, wsp, 23s rRNA, and 16s rRNA primers. Phylogenetic trees were constructed from these sequences, both for whitefly species and the endosymbionts found. In addition, morphological identification of whitefly species was made using last instar nymphs. Molecular and morphological evaluation revealed that the most abundant whitefly species was Trialeurodes variabilis (Quaintance) followed by Aleurotrachelus socialis Bondar and Bemisia tuberculata Bondar. One hundred percent of the individuals contained the primary endosymbiont Portiera. The SE Rickettsia, Hamiltonella, Wolbachia, and Fritschea were not detected in the samples tested. Prevalence of Cardinium and Arsenophonus were variable at each locality, Cardinium being most prevalent in A. socialis adults. This study is the first report on the presence of Cardinium and Arsenophonus in A. socialis and T. variabilis. It is also the first report of endosymbiotic diversity in whiteflies associated with cassava in Colombia.

RevDate: 2019-05-31

Caragata EP, Rocha MN, Pereira TN, et al (2019)

Pathogen blocking in Wolbachia-infected Aedes aegypti is not affected by Zika and dengue virus co-infection.

PLoS neglected tropical diseases, 13(5):e0007443 pii:PNTD-D-18-02063.

BACKGROUND: Wolbachia's ability to restrict arbovirus transmission makes it a promising tool to combat mosquito-transmitted diseases. Wolbachia-infected Aedes aegypti are currently being released in locations such as Brazil, which regularly experience concurrent outbreaks of different arboviruses. A. aegypti can become co-infected with, and transmit multiple arboviruses with one bite, which can complicate patient diagnosis and treatment.

Using experimental oral infection of A. aegypti and then RT-qPCR, we examined ZIKV/DENV-1 and ZIKV/DENV-3 co-infection in Wolbachia-infected A. aegypti and observed that Wolbachia-infected mosquitoes experienced lower prevalence of infection and viral load than wildtype mosquitoes, even with an extra infecting virus. Critically, ZIKV/DENV co-infection had no significant impact on Wolbachia's ability to reduce viral transmission. Wolbachia infection also strongly altered expression levels of key immune genes Defensin C and Transferrin 1, in a virus-dependent manner.

CONCLUSIONS/SIGNIFICANCE: Our results suggest that pathogen interference in Wolbachia-infected A. aegypti is not adversely affected by ZIKV/DENV co-infection, which suggests that Wolbachia-infected A. aegypti will likely prove suitable for controlling mosquito-borne diseases in environments with complex patterns of arbovirus transmission.

RevDate: 2019-05-18

Rahayu A, Saraswati U, Supriyati E, et al (2019)

Prevalence and Distribution of Dengue Virus in Aedes aegypti in Yogyakarta City before Deployment of Wolbachia Infected Aedes aegypti.

International journal of environmental research and public health, 16(10): pii:ijerph16101742.

Indonesia is one of the countries where dengue infection is prevalent. In this study we measure the prevalence and distribution of dengue virus (DENV) DENV-infected Aedes aegypti in Yogyakarta City, Indonesia, during the wet season when high dengue transmission period occurred, as baseline data before implementation of a Wolbachia-infected Aedes aegypti trial for dengue control. We applied One-Step Multiplex Real Time PCR (RT-PCR) for the type-specific-detection of dengue viruses in field-caught adult Aedes aegypti mosquitoes. In a prospective field study conducted from December 2015 to May 2016, adult female Aedes aegypti were caught from selected areas in Yogyakarta City, and then screened by using RT-PCR. During the survey period, 36 (0.12%) mosquitoes from amongst 29,252 female mosquitoes were positive for a DENV type. In total, 22.20% of dengue-positive mosquitoes were DENV-1, 25% were DENV-2, 17% were DENV-3, but none were positive for DENV-4. This study has provided dengue virus infection prevalence in field-caught Aedes aegypti and its circulating serotype in Yogyakarta City before deployment of Wolbachia-infected Aedes aegypti.

RevDate: 2019-06-10

Hosseinzadeh S, Ramsey J, Mann M, et al (2019)

Color morphology of Diaphorina citri influences interactions with its bacterial endosymbionts and 'Candidatus Liberibacter asiaticus'.

PloS one, 14(5):e0216599 pii:PONE-D-18-30769.

Diaphorina citri is a vector of 'Candidatus Liberibacter asiaticus,' (CLas), associated with Huanglongbing, (HLB, or citrus greening) disease in citrus. D. citri exhibits three different color morph variants, blue, gray and yellow. Blue morphs have a greater capacity for long-distance flight as compared to non-blue morphs, but little else is known about how color morphology influences vector characteristics. In this study, we show that the color morphology of the insect is derived from pigmented cells of the fat body. Blue morphs acquire a lower level of CLas in their bodies from infected trees as compared to their gray and yellow conspecifics, referred to in this paper collectively as non-blue morphs. Accordingly, CLas titer in citrus leaves inoculated by non-blue insects was 6-fold higher than in leaves inoculated by blue insects. Blue color morphs harbored lower titers of Wolbachia and 'Candidatus Profftella armatura,' two of the D. citri bacterial endosymbionts. Expression of hemocyanin, a copper-binding oxygen transport protein responsible for the blue coloration of hemolymph of other arthropods and mollusks, was previously correlated with blue color morphology and is highly up-regulated in insects continuously reared on CLas infected citrus trees. Based on our results, we hypothesized that a reduction of hemocyanin expression would reduce the D. citri immune response and an increase in the titer of CLas would be observed. Surprisingly, a specific 3-fold reduction of hemocyanin-1 transcript levels using RNA silencing in blue adult D. citri morphs had an approximately 2-fold reduction on the titer of CLas. These results suggest that hemocyanin signaling from the fat body may have multiple functions in the regulation of bacterial titers in D. citri, and that hemocyanin is one of multiple psyllid genes involved in regulating CLas titer.

RevDate: 2019-05-16

Teramoto T, Huang X, Armbruster P, et al (2019)

wMelpop strain of Wolbachia infection of Aedes albopictus mosquito C6/36 cells modulates dengue virus-induced host cellular transcripts and induces critical sequence alterations in dengue viral genome.

Journal of virology pii:JVI.00581-19 [Epub ahead of print].

The dengue virus (DENV) cause frequent epidemics infecting ∼390 million people annually in over 100 countries. There are no approved vaccines or antiviral drugs for treatment of infected patients. However, there is a novel approach to control DENV transmission by the mosquito vectors, Aedes aegypti and Ae. albopictus, using the Wolbachia symbiont. The wMelPop strain of Wolbachia suppresses DENV transmission and shortens the mosquito life span. However, the underlying mechanism is poorly understood. To clarify this mechanism, either naïve Ae. albopictus (C6/36) or wMelPop-C6/36 cells were infected with DENV2. Analysis of host transcript profiles by RNAseq revealed that the presence of wMelPop dramatically altered the mosquito host cell transcription in response to DENV2 infection. The viral RNA evolved from wMelPop-C6/36 cells contained low frequency mutations (∼25%) within the coding region of transmembrane domain-1 (TMD1) of E protein. Mutations with >97 % frequencies were distributed within other regions of E, NS5 RNA-dependent RNA polymerase (NS5POL) domain, the TMDs of NS2A, NS2B, and NS4B. Moreover, while DENV2-infected naïve C6/36 cells showed syncytia formation, DENV2-infected wMelPop-C6/36 cells did not. The Wolbachia-induced mutant DENV2 can readily infect and replicate in naïve C6/36 cells; whereas, in the mutant DENV2- infected BHK-21 or Vero cells, the virus replication was delayed. In LLC-MK2 cells, the mutant failed to produce plaques. Additionally, in BHK-21 cells, many mutations in the viral genome reverted to WT and compensatory mutations in NS3 gene appeared. Our results indicate that wMelPop impacts significantly the interactions of DENV2 with mosquito and mammalian host cells.Importance:Mosquito-borne diseases are of global significance causing considerable morbidity and mortality throughout the world. The dengue virus (DENV, serotypes 1-4), a member of flavivirus genus of Flaviviridae family, causes millions of infections annually. Development of a safe vaccine is hampered due to absence of cross-protection and increased risk in secondary infections due to antibody-mediated immune enhancement. Infection of vector mosquitoes with Wolbachia bacteria offers a novel countermeasure to suppress DENV transmission, but the mechanisms are poorly understood. In this study, the host transcription profiles and viral RNA sequences were analyzed in naïve Ae. albopictus (C6/36) and wMelPop-C6/36 cells by RNAseq. Our results showed that the wMelPop symbiont caused profound changes in host transcription profiles and morphology of DENV2-infected C6/36 cells. Accumulation of several mutations throughout DENV2 RNA resulted in loss of infectivity of progeny virions. Our findings offer new insights into the mechanism of Wolbachia-mediated suppression of DENV transmission.

RevDate: 2019-05-22

Shah A, Hoffman JI, H Schielzeth (2019)

Transcriptome assembly for a colour-polymorphic grasshopper (Gomphocerus sibiricus) with a very large genome size.

BMC genomics, 20(1):370 pii:10.1186/s12864-019-5756-4.

BACKGROUND: The club-legged grasshopper Gomphocerus sibiricus is a Gomphocerinae grasshopper with a promising future as model species for studying the maintenance of colour-polymorphism, the genetics of sexual ornamentation and genome size evolution. However, limited molecular resources are available for this species. Here, we present a de novo transcriptome assembly as reference resource for gene expression studies. We used high-throughput Illumina sequencing to generate 5,070,036 paired-end reads after quality filtering. We then combined the best-assembled contigs from three different de novo transcriptome assemblers (Trinity, SOAPdenovo-trans and Oases/Velvet) into a single assembly.

RESULTS: This resulted in 82,251 contigs with a N50 of 1357 and a TransRate assembly score of 0.325, which compares favourably with other orthopteran transcriptome assemblies. Around 87% of the transcripts could be annotated using InterProScan 5, BLASTx and the dammit! annotation pipeline. We identified a number of genes involved in pigmentation and green pigment metabolism pathways. Furthermore, we identified 76,221 putative single nucleotide polymorphisms residing in 8400 contigs. We also assembled the mitochondrial genome and investigated levels of sequence divergence with other species from the genus Gomphocerus. Finally, we detected and assembled Wolbachia sequences, which revealed close sequence similarity to the strain pel wPip.

CONCLUSIONS: Our study has generated a significant resource for uncovering genotype-phenotype associations in a species with an extraordinarily large genome, while also providing mitochondrial and Wolbachia sequences that will be useful for comparative studies.

RevDate: 2019-06-10

Fabre B, Korona D, Lees JG, et al (2019)

Comparison of Drosophila melanogaster Embryo and Adult Proteome by SWATH-MS Reveals Differential Regulation of Protein Synthesis, Degradation Machinery, and Metabolism Modules.

Journal of proteome research, 18(6):2525-2534.

An important area of modern biology consists of understanding the relationship between genotype and phenotype. However, to understand this relationship it is essential to investigate one of the principal links between them: the proteome. With the development of recent mass-spectrometry approaches, it is now possible to quantify entire proteomes and thus relate them to different phenotypes. Here, we present a comparison of the proteome of two extreme developmental states in the well-established model organism Drosophila melanogaster: adult and embryo. Protein modules such as ribosome, proteasome, tricarboxylic acid cycle, glycolysis, or oxidative phosphorylation were found differentially expressed between the two developmental stages. Analysis of post-translation modifications of the proteins identified in this study indicates that they generally follow the same trend as their corresponding protein. Comparison between changes in the proteome and the transcriptome highlighted patterns of post-transcriptional regulation for the subunits of protein complexes such as the ribosome and the proteasome, whereas protein from modules such as TCA cycle, glycolysis, and oxidative phosphorylation seem to be coregulated at the transcriptional level. Finally, the impact of the endosymbiont Wolbachia pipientis on the proteome of both developmental states was also investigated.

RevDate: 2019-05-10

Xu Z, Fang SM, Bakowski MA, et al (2019)

Discovery of Kirromycins with Anti- Wolbachia Activity from Streptomyces sp. CB00686.

ACS chemical biology [Epub ahead of print].

Lymphatic filariasis and onchocerciasis diseases caused by filarial parasite infections can lead to profound disability and affect millions of people worldwide. Standard mass drug administration campaigns require repetitive delivery of anthelmintics for years to temporarily block parasite transmission but do not cure infection because long-lived adult worms survive the treatment. Depletion of the endosymbiont Wolbachia, present in most filarial nematode species, results in death of adult worms and therefore represents a promising target for the treatment of filariasis. Here, we used a high-content imaging assay to screen the pure compounds collection of the natural products library at The Scripps Research Institute for anti- Wolbachia activity, leading to the identification of kirromycin B (1) as a lead candidate. Two additional congeners, kirromycin (2) and kirromycin C (3), were isolated and characterized from the same producing strain Streptomyces sp. CB00686. All three kirromycin congeners depleted Wolbachia in LDW1 Drosophila cells in vitro with half-maximal inhibitory concentrations (IC50) in nanomolar range, while doxycycline, a registered drug with anti- Wolbachia activity, showed lower activity with an IC50 of 152 ± 55 nM. Furthermore, 1-3 eliminated the Wolbachia endosymbiont in Brugia pahangi ovaries ex vivo with higher efficiency (65%-90%) at 1 μM than that of doxycycline (50%). No cytotoxicity against HEK293T and HepG2 mammalian cells was observed with 1-3 at the highest concentration (40 μM) used in the assay. These results suggest kirromycin is an effective lead scaffold, further exploration of which could potentially lead to the development of novel treatments for filarial nematode infections.

RevDate: 2019-05-09

Bakowski MA, Shiroodi RK, Liu R, et al (2019)

Discovery of short-course antiwolbachial quinazolines for elimination of filarial worm infections.

Science translational medicine, 11(491):.

Parasitic filarial nematodes cause debilitating infections in people in resource-limited countries. A clinically validated approach to eliminating worms uses a 4- to 6-week course of doxycycline that targets Wolbachia, a bacterial endosymbiont required for worm viability and reproduction. However, the prolonged length of therapy and contraindication in children and pregnant women have slowed adoption of this treatment. Here, we describe discovery and optimization of quinazolines CBR417 and CBR490 that, with a single dose, achieve >99% elimination of Wolbachia in the in vivo Litomosoides sigmodontis filarial infection model. The efficacious quinazoline series was identified by pairing a primary cell-based high-content imaging screen with an orthogonal ex vivo validation assay to rapidly quantify Wolbachia elimination in Brugia pahangi filarial ovaries. We screened 300,368 small molecules in the primary assay and identified 288 potent and selective hits. Of 134 primary hits tested, only 23.9% were active in the worm-based validation assay, 8 of which contained a quinazoline heterocycle core. Medicinal chemistry optimization generated quinazolines with excellent pharmacokinetic profiles in mice. Potent antiwolbachial activity was confirmed in L. sigmodontis, Brugia malayi, and Onchocerca ochengi in vivo preclinical models of filarial disease and in vitro selectivity against Loa loa (a safety concern in endemic areas). The favorable efficacy and in vitro safety profiles of CBR490 and CBR417 further support these as clinical candidates for treatment of filarial infections.

RevDate: 2019-06-08

Hodson CN, SJ Perlman (2019)

Population biology of a selfish sex ratio distorting element in a booklouse (Psocodea: Liposcelis).

Journal of evolutionary biology [Epub ahead of print].

Arthropods harbour a variety of selfish genetic elements that manipulate reproduction to be preferentially transmitted to future generations. A major ongoing question is to understand how these elements persist in nature. In this study, we examine the population dynamics of an unusual selfish sex ratio distorter in a recently discovered species of booklouse, Liposcelis sp. (Psocodea: Liposcelididae) to gain a better understanding of some of the factors that may affect the persistence of this element. Females that carry the selfish genetic element only ever produce daughters, although they are obligately sexual. These females also only transmit the maternal half of their genome. We performed a replicated population cage experiment, varying the initial frequency of females that harbour the selfish element, and following female frequencies for 20 months. The selfish genetic element persisted in all cages, often reaching very high (and thus severely female-biased) frequencies. Surprisingly, we also found that females that carry the selfish genetic element had much lower fitness than their nondistorter counterparts, with lower lifetime fecundity, slower development and a shorter egg-laying period. We suggest that differential fitness plays a role in the maintenance of the selfish genetic element in this species. We believe that the genetic system in this species, paternal genome elimination, which allows maternal control of offspring sex ratio, may also be important in the persistence of the selfish genetic element, highlighting the need to consider species with diverse ecologies and genetic systems when investigating the effects of sex ratio manipulators on host populations.

RevDate: 2019-05-21
CmpDate: 2019-05-21

Farnesi LC, Belinato TA, Gesto JSM, et al (2019)

Embryonic development and egg viability of wMel-infected Aedes aegypti.

Parasites & vectors, 12(1):211 pii:10.1186/s13071-019-3474-z.

BACKGROUND: Aedes aegypti is a major disease vector in urban habitats, involved in the transmission of dengue, chikungunya and Zika. Despite innumerous attempts to contain disease outbreaks, there are neither efficient vaccines nor definite vector control methods nowadays. In recent years, an innovative strategy to control arboviruses, which exploits the endosymbiotic bacterium Wolbachia pipientis, emerged with great expectations. The success of the method depends on many aspects, including Wolbachia's cytoplasmic incompatibility and pathogen interference phenotypes, as well as its effect on host fitness. In this work, we investigated the influence the Wolbachia strain wMel exerts on embryo development and egg viability and speculate on its field release use.

METHODS: Wild-type (Br or Rockefeller) and Wolbachia-harboring specimens (wMelBr) were blood-fed and submitted to synchronous egg laying for embryo development assays. Samples were analyzed for morphological markers, developmental endpoint and egg resistance to desiccation (ERD). Quiescent egg viability over time was also assessed.

RESULTS: wMelBr samples completed embryogenesis 2-3 hours later than wild-type. This delay was also observed through the onset of both morphological and physiological markers, respectively by the moments of germband extension and ERD acquisition. Following the end of embryonic development, wMelBr eggs were slightly less resistant to desiccation and showed reduced viability levels, which rapidly decayed after 40 days into quiescence, from approximately 75% to virtually 0% in less than a month.

CONCLUSIONS: Our data revealed that the wMel strain of Wolbachia slightly delays embryogenesis and also affects egg quality, both through reduced viability and desiccation resistance. These findings suggest that, although embryonic fitness is somehow compromised by wMel infection, an efficient host reproductive manipulation through cytoplasmic incompatibility seems sufficient to overcome these effects in nature and promote bacterial invasion, as shown by successful ongoing field implementation.

RevDate: 2019-05-04

Cao LJ, Jiang W, AA Hoffmann (2019)

Life History Effects Linked to an Advantage for wAu Wolbachia in Drosophila.

Insects, 10(5): pii:insects10050126.

Wolbachia endosymbiont infections can persist and spread in insect populations without causing apparent effects on reproduction of their insect hosts, but the mechanisms involved are largely unknown. Here, we test for fitness effects of the wAu infection of Drosophila simulans by comparing multiple infected and uninfected polymorphic isofemale lines derived from nature. We show a fitness advantage (higher offspring number) for lines with the wAu Wolbachia infection when breeding on grapes, but only where there was Talaromyces and Penicillium fungal mycelial growth. When breeding on laboratory medium, the wAu infection extended the development time and resulted in larger females with higher fecundity, life history traits, which may increase fitness. A chemical associated with the fungi (ochratoxin A) did not specifically alter the fitness of wAu-infected larvae, which developed slower and emerged with a greater weight regardless of toxin levels. These findings suggest that the fitness benefits of Wolbachia in natural populations may reflect life history changes that are advantageous under particular circumstances, such as when breeding occurs in rotting fruit covered by abundant mycelial growth.

RevDate: 2019-05-03

Crunkhorn S (2019)

Inhibiting Wolbachia to treat parasitic diseases.

RevDate: 2019-05-01

Kaushik S, Sharma KK, Ramani R, et al (2019)

Detection of Wolbachia Phage (WO) in Indian Lac Insect [Kerria lacca (Kerr.)] and Its Implications.

Indian journal of microbiology, 59(2):237-240.

Wolbachia, a maternally inherited bacterium induces reproductive alterations in its hosts such as feminization of males, male killing and parthenogenesis. It is the most diverse endosymbiont infecting more than 70% of the insects ranging from pests to pollinators. Kerria lacca-a hemipteran is a sedentary, oriental insect known to produce lac-the only resin of animal origin. The present study was conducted to screen the presence of Wolbachia and its associated phages in the two infrasubspecific forms (four insect lines) of K. lacca viz. kusmi and rengeeni differing from each other on the basis of host preference. Wolbachia and its associated phage were found to be prevalent in all the insect lines analyzed. We, hereby, report the presence of WO-phage (Wolbachia phage) for the first time in K. lacca. Further, phylogenetic data differentiated the kusmi and rengeeni infrasubspecific forms into two different groups on the basis of WO-phage sequences.

RevDate: 2019-05-14

Anonymous (2019)

Evolutionary Genetics of Cytoplasmic Incompatibility Genes cifA and cifB in Prophage WO of Wolbachia.

Genome biology and evolution, 11(4):1320.

RevDate: 2019-04-28

Monteiro VVS, Navegantes-Lima KC, de Lemos AB, et al (2019)

Aedes-Chikungunya Virus Interaction: Key Role of Vector Midguts Microbiota and Its Saliva in the Host Infection.

Frontiers in microbiology, 10:492.

Aedes mosquitoes are important vectors for emerging diseases caused by arboviruses, such as chikungunya (CHIKV). These viruses' main transmitting species are Aedes aegypti and Ae. albopictus, which are present in tropical and temperate climatic areas all over the globe. Knowledge of vector characteristics is fundamentally important to the understanding of virus transmission. Only female mosquitoes are able to transmit CHIKV to the vertebrate host since they are hematophagous. In addition, mosquito microbiota is fundamentally important to virus infection in the mosquito. Microorganisms are able to modulate viral transmission in the mosquito, such as bacteria of the Wolbachia genus, which are capable of preventing viral infection, or protozoans of the Ascogregarina species, which are capable of facilitating virus transmission between mosquitoes and larvae. The competence of the mosquito is also important in the transmission of the virus to the vertebrate host, since their saliva has several substances with biological effects, such as immunomodulators and anticoagulants, which are able to modulate the host's response to the virus, interfering in its pathogenicity and virulence. Understanding the Aedes vector-chikungunya interaction is fundamentally important since it can enable the search for new methods of combating the virus' transmission.

RevDate: 2019-04-22

Mains JW, Kelly PH, Dobson KL, et al (2019)

Localized Control of Aedes aegypti (Diptera: Culicidae) in Miami, FL, via Inundative Releases of Wolbachia-Infected Male Mosquitoes.

Journal of medical entomology pii:5475244 [Epub ahead of print].

As part of the response to autochthonous Zika transmission in the United States, the City of South Miami implemented a 6-mo period in which Wolbachia-infected WB1 Aedes aegypti (L.) males were released into an ~170-acre area. Intracellular Wolbachia bacteria infections in Ae. aegypti cause early embryonic arrest (known as cytoplasmic incompatibility [CI]) and egg hatch failure, and inundative introductions have been suggested as a potential control tool. Throughout the release period, the Ae. aegypti population was monitored within both the release area and an equivalent area that did not receive WB1 male releases. The results show a significant reduction in egg hatch at the area receiving WB1 males, which is consistent with expectations for CI. Similarly, the number of Ae. aegypti was significantly reduced at the area receiving WB1 males, relative to the untreated area. The observed population reduction and results encourage additional work and replication of the Wolbachia biopesticide approach against Ae. aegypti, as an additional tool to be integrated with existing control tools for the control of this medically important vector and nuisance pest.

RevDate: 2019-05-24

Vila A, Estrada-Peña A, Altet L, et al (2019)

Endosymbionts carried by ticks feeding on dogs in Spain.

Ticks and tick-borne diseases, 10(4):848-852.

Studies on tick microbial communities historically focused on tick-borne pathogens. However, there is an increasing interest in capturing relationships among non-pathogenic endosymbionts and exploring their relevance for tick biology. The present study included a total of 1600 adult ticks collected from domestic dogs in 4 different biogeographical regions of Spain. Each pool formed by 1 to 10 halves of individuals representing one specific ticks species was examined by PCR for the presence of Coxiellaceae, Rickettsia spp., Rickettsiales, Wolbachia spp., and other bacterial DNA. Of the pools analyzed, 92% tested positive for endosymbiont-derived DNA. Coxiella spp. endosymbionts were the most prevalent microorganisms, being always present in Rhipicephalus sanguineus sensu lato (s.l.) pools. Rickettsia spp. DNA was detected in 60% of Dermacentor reticulatus pools and 40% of R. sanguineus s.l. pools, with a higher diversity of Rickettsia species in R. sanguineus s.l. pools. Our study reveals a negative relationship of Rickettsia massiliae with the presence of tick-borne pathogens in the same pool of ticks. An additional endosymbiont, 'Candidatus Rickettsiella isopodorum', was only detected in D. reticulatus pools. Data from this study indicate that dogs in Spain are exposed to several endosymbionts. Due to the importance of tick-borne pathogens, characterizing the role of endosymbionts for tick physiology and prevalence, may lead to novel control strategies.

RevDate: 2019-05-17

Shropshire JD, Leigh B, Bordenstein SR, et al (2019)

Models and Nomenclature for Cytoplasmic Incompatibility: Caution over Premature Conclusions - A Response to Beckmann et al.

Trends in genetics : TIG, 35(6):397-399.

RevDate: 2019-05-19

Ross PA, Ritchie SA, Axford JK, et al (2019)

Loss of cytoplasmic incompatibility in Wolbachia-infected Aedes aegypti under field conditions.

PLoS neglected tropical diseases, 13(4):e0007357 pii:PNTD-D-18-01933.

Wolbachia bacteria are now being introduced into Aedes aegypti mosquito populations for dengue control. When Wolbachia infections are at a high frequency, they influence the local transmission of dengue by direct virus blocking as well as deleterious effects on vector mosquito populations. However, the effectiveness of this strategy could be influenced by environmental temperatures that decrease Wolbachia density, thereby reducing the ability of Wolbachia to invade and persist in the population and block viruses. We reared wMel-infected Ae. aegypti larvae in the field during the wet season in Cairns, North Queensland. Containers placed in the shade produced mosquitoes with a high Wolbachia density and little impact on cytoplasmic incompatibility. However, in 50% shade where temperatures reached 39°C during the day, wMel-infected males partially lost their ability to induce cytoplasmic incompatibility and females had greatly reduced egg hatch when crossed to infected males. In a second experiment under somewhat hotter conditions (>40°C in 50% shade), field-reared wMel-infected females had their egg hatch reduced to 25% when crossed to field-reared wMel-infected males. Wolbachia density was reduced in 50% shade for both sexes in both experiments, with some mosquitoes cleared of their Wolbachia infections entirely. To investigate the critical temperature range for the loss of Wolbachia infections, we held Ae. aegypti eggs in thermocyclers for one week at a range of cyclical temperatures. Adult wMel density declined when eggs were held at 26-36°C or above with complete loss at 30-40°C, while the density of wAlbB remained high until temperatures were lethal. These findings suggest that high temperature effects on Wolbachia are potentially substantial when breeding containers are exposed to partial sunlight but not shade. Heat stress could reduce the ability of Wolbachia infections to invade mosquito populations in some locations and may compromise the ability of Wolbachia to block virus transmission in the field. Temperature effects may also have an ecological impact on mosquito populations given that a proportion of the population becomes self-incompatible.

RevDate: 2019-06-10

Meany MK, Conner WR, Richter SV, et al (2019)

Loss of cytoplasmic incompatibility and minimal fecundity effects explain relatively low Wolbachia frequencies in Drosophila mauritiana.

Evolution; international journal of organic evolution, 73(6):1278-1295.

Maternally transmitted Wolbachia bacteria infect about half of all insect species. Many Wolbachia cause cytoplasmic incompatibility (CI) and reduced egg hatch when uninfected females mate with infected males. Although CI produces a frequency-dependent fitness advantage that leads to high equilibrium Wolbachia frequencies, it does not aid Wolbachia spread from low frequencies. Indeed, the fitness advantages that produce initial Wolbachia spread and maintain non-CI Wolbachia remain elusive. wMau Wolbachia infecting Drosophila mauritiana do not cause CI, despite being very similar to CI-causing wNo from Drosophila simulans (0.068% sequence divergence over 682,494 bp), suggesting recent CI loss. Using draft wMau genomes, we identify a deletion in a CI-associated gene, consistent with theory predicting that selection within host lineages does not act to increase or maintain CI. In the laboratory, wMau shows near-perfect maternal transmission; but we find no significant effect on host fecundity, in contrast to published data. Intermediate wMau frequencies on the island of Mauritius are consistent with a balance between unidentified small, positive fitness effects and imperfect maternal transmission. Our phylogenomic analyses suggest that group-B Wolbachia, including wMau and wPip, diverged from group-A Wolbachia, such as wMel and wRi, 6-46 million years ago, more recently than previously estimated.

RevDate: 2019-04-19

Michalik K, Szklarzewicz T, Kalandyk-Kołodziejczyk M, et al (2019)

Bacterial associates of Orthezia urticae, Matsucoccus pini, and Steingelia gorodetskia - scale insects of archaeoccoid families Ortheziidae, Matsucoccidae, and Steingeliidae (Hemiptera, Coccomorpha).

Protoplasma pii:10.1007/s00709-019-01377-z [Epub ahead of print].

The biological nature, ultrastructure, distribution, and mode of transmission between generations of the microorganisms associated with three species (Orthezia urticae, Matsucoccus pini, Steingelia gorodetskia) of primitive families (archaeococcoids = Orthezioidea) of scale insects were investigated by means of microscopic and molecular methods. In all the specimens of Orthezia urticae and Matsucoccus pini examined, bacteria Wolbachia were identified. In some examined specimens of O. urticae, apart from Wolbachia, bacteria Sodalis were detected. In Steingelia gorodetskia, the bacteria of the genus Sphingomonas were found. In contrast to most plant sap-sucking hemipterans, the bacterial associates of O. urticae, M. pini, and S. gorodetskia are not harbored in specialized bacteriocytes, but are dispersed in the cells of different organs. Ultrastructural observations have shown that bacteria Wolbachia in O. urticae and M. pini, Sodalis in O. urticae, and Sphingomonas in S. gorodetskia are transovarially transmitted from mother to progeny.

RevDate: 2019-04-26

Sabūnas V, Radzijevskaja J, Sakalauskas P, et al (2019)

Dirofilaria repens in dogs and humans in Lithuania.

Parasites & vectors, 12(1):177 pii:10.1186/s13071-019-3406-y.

BACKGROUND: In Lithuania, the first case of canine subcutaneous dirofilariosis was recorded in 2010. Since then, an increasing number of cases of canine dirofilariosis have been documented in different veterinary clinics throughout the country. Human dirofilariosis was diagnosed in Lithuania for the first time in September 2011. However, to the authors' knowledge, there are no published data on the presence and prevalence of autochthonous dirofilariosis in dogs and humans in the country. The present study provides information about the predominant species and prevalence of Dirofilaria in dogs and describes the cases of human dirofilariosis in Lithuania. It also outlines PCR detection of the bacterial endosymbiont Wolbachia that contributes to the inflammatory features of filarioid infection.

RESULTS: A total of 2280 blood samples and six adult worms from pet and shelter dogs were collected in the central and eastern regions of Lithuania in 2013-2015. Based on their morphological appearance, morphometric measurements and molecular analysis, all the adult nematodes were identified as Dirofilaria repens. The diagnosis of microfilariae in blood samples was based on blood smear analysis and Knott's test. The PCR and sequence analysis of the ribosomal DNA ITS2 region and cox1 gene confirmed the presence of D. repens. Overall, 61 (2.7%) of the 2280 blood samples were found to be positive for the presence of D. repens. The infection rate of D. repens was significantly higher in shelter dogs (19.0%; 19/100) than in pet dogs (1.9%; 42/2180) (χ2 = 100.039, df = 1, P < 0.0001). Forty-nine DNA samples of D. repens-infected dogs were tested for the presence of the bacterial endosymbiont Wolbachia and, of these, 40 samples (81.6%) were found to be positive. Three ocular and six subcutaneous cases of human dirofilariosis were diagnosed in Lithuania in the period 2011-2018.

CONCLUSIONS: To the authors' knowledge, this is the first report of autochthonous D. repens infection in dogs and humans in Lithuania. The present data demonstrate that D. repens is the main etiological agent of dirofilariosis in Lithuania. The DNA of the filarioid endosymbiotic bacterium Wolbachia was detected in the vast majority of dogs infected with D. repens.

RevDate: 2019-04-18

Carvajal TM, Capistrano JDR, Hashimoto K, et al (2018)

Detection and distribution of Wolbachia endobacteria in Culex quinquefasciatus populations (Diptera : Culicidae) from Metropolitan Manila, Philippines.

Journal of vector borne diseases, 55(4):265-270.

Background & objectives: Culex quinquefasciatus is a peridomestic mosquito known for its ability to transmit pathogenic diseases such as filariasis and Japanese encephalitis. The development and use of novel and innovative vector control measures such as the utilization of Wolbachia, along with the existing ones, are necessary to prevent the transmission of these diseases. Studies exploring the diversity of Wolbachia, particularly in Cx. quinquefasciatus are very limited in the Philippines. Thus, the aim of the study was to detect the presence, distribution, and phylogenetic relationship of Wolbachia infections in Cx. quinquefasciatus in Metropolitan Manila, Philippines.

Methods: Adult Cx. quinquefasciatus mosquitoes were collected using a commercially available light-trap from May 2014-January 2015. Based on their sampling grids (n = 51), the adult mosquito abdomens were pooled and subjected to Wolbachia surface protein (wsp) gene amplification assay. Five selected wsp-positive samples were then sequenced and further analyzed to infer their phylogenetic relationship with known Wolbachia strains.

Results: A total of 1090 adult Cx. quinquefasciatus mosquitoes were collected. Pooled abdomens (n = 53) were then sorted based on their sampling grids for subsequent screening of wsp gene. Wolbachia infection rate was 59% (31/53). These infections were located at 29 (57%) sampling grids, and were observed to be widely distributed in the study area. Phylogenetic analysis indicated that the sample sequences were Wolbachia pipientis isolated from known hosts, Cx. pipiens and Cx. quinquefasciatus belonging to supergroup B clade.

The study was able to demonstrate the prevalence and distribution of Wolbachia in Cx. quinquefasciatus in Metropolitan Manila, Philippines. The findings of this study are geared towards proposing a vector control program that utilizes the potential of Wolbachia as a biological control agent in preventing the transmission of Culex-borne diseases.

RevDate: 2019-05-24

Muñoz-Leal S, Macedo C, Gonçalves TC, et al (2019)

Detected microorganisms and new geographic records of Ornithodoros rietcorreai (Acari: Argasidae) from northern Brazil.

Ticks and tick-borne diseases, 10(4):853-861.

Reliable data on distributional ranges of soft ticks (Argasidae) and assessments of putative tick-borne agents enhance the understanding on tick-associated microorganisms. A total of 96 ticks morphologicaly and molecularly identified as Ornithodoros rietcorreai were collected in Tocantins State, Brazil, using Noireau traps with living bait as CO2 source. Ninety-six ticks (54 nymphs, 32 males, 10 females) with different engorgement degrees were collected. Fourty-seven (48.9%) of them were individually screened by PCR for detecting bacteria of Anaplasmataceae family and genera Rickettsia, and Borrelia. The presence of protozoans of the genus Babesia was assessed as well. Fourty seven ticks were submitted to analysis. Nine ticks (19.1%) yielded sequences for gltA and htrA genes most identical with a series of endosymbiont rickettsiae and Rickettsia bellii, respectively. Upon two ticks (4.2%) we retrieved DNA of a potential new Wolbachia sp., and DNA of a putative novel Hepatozoon was characterized from three (6.4%) specimens. No DNA of Babesia or Borrelia was detected. Remarkably, amplicons of unidentified eukaryotic organisms, most closely related with apicomplexans but also with dinoflagellates (91% of identity after BLAST analyses), were recovered from two ticks (4.2%) using primers designed for Babesia 18S rRNA gene. Our records expand the distribution of O. rietcorreai into Brazilian Cerrado biome and introduce the occurrence of microorganisms in this tick species.

RevDate: 2019-04-24

Dhaygude K, Nair A, Johansson H, et al (2019)

The first draft genomes of the ant Formica exsecta, and its Wolbachia endosymbiont reveal extensive gene transfer from endosymbiont to host.

BMC genomics, 20(1):301 pii:10.1186/s12864-019-5665-6.

BACKGROUND: Adapting to changes in the environment is the foundation of species survival, and is usually thought to be a gradual process. However, transposable elements (TEs), epigenetic modifications, and/or genetic material acquired from other organisms by means of horizontal gene transfer (HGTs), can also lead to novel adaptive traits. Social insects form dense societies, which attract and maintain extra- and intracellular accessory inhabitants, which may facilitate gene transfer between species. The wood ant Formica exsecta (Formicidae; Hymenoptera), is a common ant species throughout the Palearctic region. The species is a well-established model for studies of ecological characteristics and evolutionary conflict.

RESULTS: In this study, we sequenced and assembled draft genomes for F. exsecta and its endosymbiont Wolbachia. The F. exsecta draft genome is 277.7 Mb long; we identify 13,767 protein coding genes, for which we provide gene ontology and protein domain annotations. This is also the first report of a Wolbachia genome from ants, and provides insights into the phylogenetic position of this endosymbiont. We also identified multiple horizontal gene transfer events (HGTs) from Wolbachia to F. exsecta. Some of these HGTs have also occurred in parallel in multiple other insect genomes, highlighting the extent of HGTs in eukaryotes.

CONCLUSION: We present the first draft genome of ant F. exsecta, and its endosymbiont Wolbachia (wFex), and show considerable rates of gene transfer from the symbiont to the host. We expect that especially the F. exsecta genome will be valuable resource in further exploration of the molecular basis of the evolution of social organization.

RevDate: 2019-05-10

Zheng B, Liu X, Tang M, et al (2019)

Use of age-stage structural models to seek optimal Wolbachia-infected male mosquito releases for mosquito-borne disease control.

Journal of theoretical biology, 472:95-109.

Due to the lack of vaccines and effective clinical cures, current methods to control mosquito-borne viral diseases such as dengue and Zika are primarily targeting to eradicate the major mosquito vectors. However, traditional means, including larval source reduction and applications of insecticides etc, are not sufficient to keep vector population density below the epidemic risk threshold. An innovative and operational strategy is to release Wolbachia-infected male mosquitoes into wild areas to sterilize wild female mosquitoes by cytoplasmic incompatibility. To help design optimal release strategies before large scale and expensive operations, we started with an age-stage discrete model to track daily abundances of wild female mosquitoes, which fitted the field data collected by Guangzhou Center for Disease Control and Prevention from 2015 to 2017 with an average Pearson correlation coefficient 0.7283. Then, we modeled the Wolbachia interference by introducing the proportional releases of Wolbachia-infected males, and eight optimal release policies which guarantee more than 95% suppression efficiency were sought. Finally, we assessed the robustness of the optimality of the eight release policies by allowing the migration of females or the contamination of Wolbachia-infected females by two further extended mathematical models.

RevDate: 2019-04-17

Lefoulon E, Vaisman N, Frydman HM, et al (2019)

Large Enriched Fragment Targeted Sequencing (LEFT-SEQ) Applied to Capture of Wolbachia Genomes.

Scientific reports, 9(1):5939 pii:10.1038/s41598-019-42454-w.

Symbiosis is a major force of evolutionary change, influencing virtually all aspects of biology, from population ecology and evolution to genomics and molecular/biochemical mechanisms of development and reproduction. A remarkable example is Wolbachia endobacteria, present in some parasitic nematodes and many arthropod species. Acquisition of genomic data from diverse Wolbachia clades will aid in the elucidation of the different symbiotic mechanisms(s). However, challenges of de novo assembly of Wolbachia genomes include the presence in the sample of host DNA: nematode/vertebrate or insect. We designed biotinylated probes to capture large fragments of Wolbachia DNA for sequencing using PacBio technology (LEFT-SEQ: Large Enriched Fragment Targeted Sequencing). LEFT-SEQ was used to capture and sequence four Wolbachia genomes: the filarial nematode Brugia malayi, wBm, (21-fold enrichment), Drosophila mauritiana flies (2 isolates), wMau (11-fold enrichment), and Aedes albopictus mosquitoes, wAlbB (200-fold enrichment). LEFT-SEQ resulted in complete genomes for wBm and for wMau. For wBm, 18 single-nucleotide polymorphisms (SNPs), relative to the wBm reference, were identified and confirmed by PCR. A limit of LEFT-SEQ is illustrated by the wAlbB genome, characterized by a very high level of insertion sequences elements (ISs) and DNA repeats, for which only a 20-contig draft assembly was achieved.

RevDate: 2019-05-02
CmpDate: 2019-04-18

Lee WS, Webster JA, Madzokere ET, et al (2019)

Mosquito antiviral defense mechanisms: a delicate balance between innate immunity and persistent viral infection.

Parasites & vectors, 12(1):165 pii:10.1186/s13071-019-3433-8.

Mosquito-borne diseases are associated with major global health burdens. Aedes spp. and Culex spp. are primarily responsible for the transmission of the most medically important mosquito-borne viruses, including dengue virus, West Nile virus and Zika virus. Despite the burden of these pathogens on human populations, the interactions between viruses and their mosquito hosts remain enigmatic. Viruses enter the midgut of a mosquito following the mosquito's ingestion of a viremic blood meal. During infection, virus recognition by the mosquito host triggers their antiviral defense mechanism. Of these host defenses, activation of the RNAi pathway is the main antiviral mechanism, leading to the degradation of viral RNA, thereby inhibiting viral replication and promoting viral clearance. However, whilst antiviral host defense mechanisms limit viral replication, the mosquito immune system is unable to effectively clear the virus. As such, these viruses can establish persistent infection with little or no fitness cost to the mosquito vector, ensuring life-long transmission to humans. Understanding of the mosquito innate immune response enables the discovery of novel antivectorial strategies to block human transmission. This review provides an updated and concise summary of recent studies on mosquito antiviral immune responses, which is a key determinant for successful virus transmission. In addition, we will also discuss the factors that may contribute to persistent infection in mosquito hosts. Finally, we will discuss current mosquito transmission-blocking strategies that utilize genetically modified mosquitoes and Wolbachia-infected mosquitoes for resistance to pathogens.

RevDate: 2019-05-13

Sigle LT, EA McGraw (2019)

Expanding the canon: Non-classical mosquito genes at the interface of arboviral infection.

Insect biochemistry and molecular biology, 109:72-80.

Mosquito transmitted viruses cause significant morbidity and mortality in human populations. Despite the use of insecticides and other measures of vector control, arboviral diseases are on the rise. One potential solution for limiting disease transmission to humans is to render mosquitoes refractory to viral infection through genetic modification. Substantial research effort in Drosophila, Aedes and Anopheles has helped to define the major innate immune pathways, including Toll, IMD, Jak/Stat and RNAi, however we still have an incomplete picture of the mosquito antiviral response. Transcriptional profiles of virus-infected insects reveal a much wider range of pathways activated by the process of infection. Within these lists of genes are unexplored mosquito candidates of viral defense. Wolbachia species are endosymbiotic bacteria that naturally limit arboviral infection in mosquitoes. Our understanding of the Wolbachia-mediated viral blocking mechanism is poor, but it does not appear to operate via the classical immune pathways. Herein, we reviewed the transcriptomic response of mosquitoes to multiple viral species and put forth consensus gene types/families outside the immune canon whose expression responds to infection, including cytoskeleton and cellular trafficking, the heat shock response, cytochromes P450, cell proliferation, chitin and small RNAs. We then examine emerging evidence for their functional role in viral resistance in diverse insect and mammalian hosts and their potential role in Wolbachia-mediated viral blocking. These candidate gene families offer novel avenues for research into the nature of insect viral defense.

RevDate: 2019-05-20

Clare RH, Clark R, Bardelle C, et al (2019)

Development of a High-Throughput Cytometric Screen to Identify Anti- Wolbachia Compounds: The Power of Public-Private Partnership.

SLAS discovery : advancing life sciences R & D, 24(5):537-547.

The Anti- Wolbachia (A·WOL) consortium at the Liverpool School of Tropical Medicine (LSTM) has partnered with the Global High-Throughput Screening (HTS) Centre at AstraZeneca to create the first anthelmintic HTS for neglected tropical diseases (NTDs). The A·WOL consortium aims to identify novel macrofilaricidal drugs targeting the essential bacterial symbiont (Wolbachia) of the filarial nematodes causing onchocerciasis and lymphatic filariasis. Working in collaboration, we have validated a robust high-throughput assay capable of identifying compounds that selectively kill Wolbachia over the host insect cell. We describe the development and validation process of this complex, phenotypic high-throughput assay and provide an overview of the primary outputs from screening the AstraZeneca library of 1.3 million compounds.

RevDate: 2019-05-08
CmpDate: 2019-05-08

Landmann F (2019)

The Wolbachia Endosymbionts.

Microbiology spectrum, 7(2):.

The Wolbachia endosymbionts encompass a large group of intracellular bacteria of biomedical and veterinary relevance, closely related to Anaplasma, Ehrlichia, and Rickettsia. This genus of Gram-negative members of the Alphaproteobacteria does not infect vertebrates but is instead restricted to ecdysozoan species, including terrestrial arthropods and a family of parasitic filarial nematodes, the Onchocercidae. The Wolbachia profoundly impact not only the ecology and evolution but also the reproductive biology of their hosts, through a wide range of symbiotic interactions. Because they are essential to the survival and reproduction of their filarial nematode hosts, they represent an attractive target to fight filariasis. Their abilities to spread through insect populations and to affect vector competence through pathogen protection have made Wolbachia a staple for controlling vector-borne diseases. Estimated to be present in up to 66% of insect species, the Wolbachia are probably the most abundant endosymbionts on earth. Their success resides in their unique capacity to infect and manipulate the host germ line to favor their vertical transmission through the maternal lineage. Because the Wolbachia resist genetic manipulation and growth in axenic culture, our understanding of their biology is still in its infancy. Despite these limitations, the "-omics" revolution combined with the use of well-established and emerging experimental host models is accelerating our comprehension of the host phenotypes caused by Wolbachia, and the identification of Wolbachia effectors is ongoing.

RevDate: 2019-04-21

Walden PM, Whitten AE, Premkumar L, et al (2019)

The atypical thiol-disulfide exchange protein α-DsbA2 from Wolbachia pipientis is a homotrimeric disulfide isomerase.

Acta crystallographica. Section D, Structural biology, 75(Pt 3):283-295.

Disulfide-bond-forming (DSB) oxidative folding enzymes are master regulators of virulence that are localized to the periplasm of many Gram-negative bacteria. The archetypal DSB machinery from Escherichia coli K-12 consists of a dithiol-oxidizing redox-relay pair (DsbA/B), a disulfide-isomerizing redox-relay pair (DsbC/D) and the specialist reducing enzymes DsbE and DsbG that also interact with DsbD. By contrast, the Gram-negative bacterium Wolbachia pipientis encodes just three DSB enzymes. Two of these, α-DsbA1 and α-DsbB, form a redox-relay pair analogous to DsbA/B from E. coli. The third enzyme, α-DsbA2, incorporates a DsbA-like sequence but does not interact with α-DsbB. In comparison to other DsbA enzymes, α-DsbA2 has ∼50 extra N-terminal residues (excluding the signal peptide). The crystal structure of α-DsbA2ΔN, an N-terminally truncated form in which these ∼50 residues are removed, confirms the DsbA-like nature of this domain. However, α-DsbA2 does not have DsbA-like activity: it is structurally and functionally different as a consequence of its N-terminal residues. Firstly, α-DsbA2 is a powerful disulfide isomerase and a poor dithiol oxidase: i.e. its role is to shuffle rather than to introduce disulfide bonds. Moreover, small-angle X-ray scattering (SAXS) of α-DsbA2 reveals a homotrimeric arrangement that differs from those of the other characterized bacterial disulfide isomerases DsbC from Escherichia coli (homodimeric) and ScsC from Proteus mirabilis (PmScsC; homotrimeric with a shape-shifter peptide). α-DsbA2 lacks the shape-shifter motif and SAXS data suggest that it is less flexible than PmScsC. These results allow conclusions to be drawn about the factors that are required for functionally equivalent disulfide isomerase enzymatic activity across structurally diverse protein architectures.

RevDate: 2019-05-05

Pillonel T, Bertelli C, Aeby S, et al (2019)

Sequencing the Obligate Intracellular Rhabdochlamydia helvetica within Its Tick Host Ixodes ricinus to Investigate Their Symbiotic Relationship.

Genome biology and evolution, 11(4):1334-1344.

The Rhabdochlamydiaceae family is one of the most widely distributed within the phylum Chlamydiae, but most of its members remain uncultivable. Rhabdochlamydia 16S rRNA was recently reported in more than 2% of 8,534 pools of ticks from Switzerland. Shotgun metagenomics was performed on a pool of five female Ixodes ricinus ticks presenting a high concentration of chlamydial DNA, allowing the assembly of a high-quality draft genome. About 60% of sequence reads originated from a single bacterial population that was named "Candidatus Rhabdochlamydia helvetica" whereas only few thousand reads mapped to the genome of "Candidatus Midichloria mitochondrii," a symbiont normally observed in all I. ricinus females. The 1.8 Mbp genome of R. helvetica is smaller than other Chlamydia-related bacteria. Comparative analyses with other chlamydial genomes identified transposases of the PD-(D/E)XK nuclease family that are unique to this new genome. These transposases show evidence of interphylum horizontal gene transfers between multiple arthropod endosymbionts, including Cardinium spp. (Bacteroidetes) and diverse proteobacteria such as Wolbachia, Rickettsia spp. (Rickettsiales), and Caedimonas varicaedens (Holosporales). Bacterial symbionts were previously suggested to provide B-vitamins to hematophagous hosts. However, incomplete metabolic capacities including for B-vitamin biosynthesis, high bacterial density and limited prevalence suggest that R. helvetica is parasitic rather than symbiotic to its host. The identification of novel Rhabdochlamydia strains in different hosts and their sequencing will help understanding if members of this genus have become highly specialized parasites with reduced genomes, like the Chlamydiaceae, or if they could be pathogenic to humans using ticks as a transmission vector.

RevDate: 2019-05-01

Barradas I, V Vázquez (2019)

Backward Bifurcation as a Desirable Phenomenon: Increased Fecundity Through Infection.

Bulletin of mathematical biology, 81(6):2029-2050.

Backward or subcritical bifurcation is usually considered an undesirable phenomenon in epidemiology since control measures require a reduction in R0 not below one but below a much smaller value. However, there are contexts for which a backward or subcritical bifurcation is not a bad thing; it can even be desirable. Such is the case for any characteristic that can be passed to the next generation (genetically fixed or not) and that increases the effective reproductive rate of the host or the total number of individuals. In the present work, we study an epidemiological model consisting of two classes, susceptible and "infected" individuals; the model considers a characteristic that is passed from "infected" to "susceptible" by direct "contact," for instance increased fecundity. We analyze conditions for the appearance of a backward or subcritical bifurcation. We discuss the advantage for the population under infection, since the total number of individuals increases at equilibrium. If one takes that as a proxy for increased fitness, it would increase the species' ecological success. One key element in the model is the fact that "susceptible" individuals have "susceptible" descendants, but "infected" individuals can have "infected" descendants as well as "susceptible" ones. A somehow rare addition for epidemiological models, the fact that "infected" individuals reproduce more rapidly than the susceptible ones, leads to unexpected consequences. Facilitating the "inoculation" increases the total population size, i.e., the backward or subcritical bifurcation appears, with desirable consequences for the population. We show that an increase in the number of susceptible newborns is the main reason for the appearance of a backward or subcritical bifurcation, which induces a bigger population size. We analyze the effect of different combinations of susceptible/infected birth rates. This kind of phenomenon has been observed for bacterial infections in several insects-bacteria and nematodes-bacteria interactions; in particular, it has been intensely studied in interactions of wasps and flies with the genus Wolbachia. It has also been shown in amphibians.

RevDate: 2019-04-03

Ali H, Muhammad A, Sanda NB, et al (2019)

Pyrosequencing Uncovers a Shift in Bacterial Communities Across Life Stages of Octodonta nipae (Coleoptera: Chrysomelidae).

Frontiers in microbiology, 10:466.

Bacterial symbionts of insects affect a wide array of host traits including fitness and immunity. Octodonta nipae (Maulik), commonly known as hispid leaf beetle is a destructive palm pest around the world. Understanding the dynamics of microbiota is essential to unravel the complex interplay between O. nipae and its bacterial symbionts. In this study, bacterial 16S rRNA V3-V4 region was targeted to decipher the diversity and dynamics of bacterial symbionts across different life stages [eggs, larvae, pupae, and adult (male and female)] and reproductive organs (ovaries and testis) of O. nipae. Clustering analysis at ≥97% similarity threshold produced 3,959 operational taxonomic units (OTUs) that belonged to nine different phyla. Proteobacteria, Actinobacteria, and Firmicutes represented the bulk of taxa that underwent notable changes during metamorphosis. Enterobacteriaceae and Dermabacteraceae were the most abundant families in immature stages (eggs, larvae, and pupae), while Anaplasmataceae family was dominated in adults (male and female) and reproductive organs (ovaries and testis). The genus Serratia and Lactococcus were most abundant in eggs, whereas Pantoea and Brachybacterium represented the bulk of larvae and pupae microbiota. Interestingly the genus Wolbachia found positive to all tested samples and was recorded extremely high (>64%) in the adults and reproductive organs. The bacteria varied across the developmental stages and responsible for various metabolic activities. Selection choice exerted by the insect host as a result of its age or developmental stage could be the main reason to ascertain the shift in the bacteria populations. Maternally inherited Wolbachia was found to be an obligate endosymbiont infecting all tested life stages, body parts, and tissues. These outcomes foster our understanding of the intricate associations between bacteria and O. nipae and will incorporate in devising novel pest control strategies against this palm pest.

RevDate: 2019-04-29

Zhang X, Li TP, Zhou CY, et al (2019)

Antibiotic exposure perturbs the bacterial community in the small brown planthopper Laodelphax striatellus.

Insect science [Epub ahead of print].

Bacteria symbionts in herbivores play an important role in host biology and ecology, and are affected by environmental factors such as temperature, diet, habitat, antibiotics and so on. However, the effects of antibiotics on the microbiome of the small brown planthopper Laodelphax striatellus (SBPH) remain unclear. Here, we studied the effects of tetracycline on the diversity and composition of bacterial colonies in different tissues of SBPH using high throughput sequencing of 16S ribosomal RNA amplicons. Our results show that Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria were most abundant in SBPH, and the genera Asaia and Wolbachia were most abundant in all body parts of SBPH. Antibiotic treatment had persistent effects on the composition of the SBPH microbiome. Tetracycline depleted the population of Firmicutes, Bacteroidetes, Tenericutes and Fusobacteria, and nearly 100% eliminated Wolbachia, Bacteroides and Abiotrophia in SBPH. Together, these results suggest that antibiotic exposure affects the bacteria symbionts of different body parts in SBPH and will facilitate future studies of the bacterial symbionts of arthropod hosts.

RevDate: 2019-03-27

Kolasa M, Ścibior R, Mazur MA, et al (2019)

How Hosts Taxonomy, Trophy, and Endosymbionts Shape Microbiome Diversity in Beetles.

Microbial ecology pii:10.1007/s00248-019-01358-y [Epub ahead of print].

Bacterial communities play a crucial role in the biology, ecology, and evolution of multicellular organisms. In this research, the microbiome of 24 selected beetle species representing five families (Carabidae, Staphylinidae, Curculionidae, Chrysomelidae, Scarabaeidae) and three trophic guilds (carnivorous, herbivorous, detrivorous) was examined using 16S rDNA sequencing on the Illumina platform. The aim of the study was to compare diversity within and among species on various levels of organization, including evaluation of the impact of endosymbiotic bacteria. Collected data showed that beetles possess various bacterial communities and that microbiota of individuals of particular species hosts are intermixed. The most diverse microbiota were found in Carabidae and Scarabaeidae; the least diverse, in Staphylinidae. On higher organization levels, the diversity of bacteria was more dissimilar between families, while the most distinct with respect to their microbiomes were trophic guilds. Moreover, eight taxa of endosymbiotic bacteria were detected including common genera such as Wolbachia, Rickettsia, and Spiroplasma, as well as the rarely detected Cardinium, Arsenophonus, Buchnera, Sulcia, Regiella, and Serratia. There were no correlations among the abundance of the most common Wolbachia and Rickettsia; a finding that does not support the hypothesis that these bacteria occur interchangeably. The abundance of endosymbionts only weakly and negatively correlates with diversity of the whole microbiome in beetles. Overall, microbiome diversity was found to be more dependent on host phylogeny than on the abundance of endosymbionts. This is the first study in which bacteria diversity is compared between numerous species of beetles in a standardized manner.

RevDate: 2019-05-07

Konecka E, Olszanowski Z, R Koczura (2019)

Wolbachia of phylogenetic supergroup E identified in oribatid mite Gustavia microcephala (Acari: Oribatida).

Molecular phylogenetics and evolution, 135:230-235.

Heritable endosymbionts have been observed in arthropod and nematode hosts. The most-known among them is Wolbachia. Although the bacterium was previously identified in oribatid mites (Acari: Oribatida), it was not assigned to any phylogenetic group. Endosymbionts have a profound influence on their hosts, playing various functions that affect invertebrate's biology such as changing the way of reproduction. Oribatida provide the very unique examples of groups in which even whole families appear to be thelytokous, so we considered that it is worth to investigate the occurrence of endosymbiotic microorganisms in oribatid mites, especially that the knowledge on the symbionts occurrence in this invertebrate group is negligible. We report for the first time Wolbachia in oribatid mite Gustavia microcephala. The sequences of 16S rDNA, gltA, and ftsZ genes of the endosymbiont from the mite showed the highest similarity to Wolbachia found in Collembola. Phylogenetic analysis based on single gene and concatenated alignments of three genes revealed that the bacteria from G. microcephala and Collembola were related and clustered together with supergroup E. Relatively close relationship of Wolbachia from oribatid and collembolan hosts might mean at the evolutionary scale that horizontal transfer of bacteria between these two groups of invertebrates may take place.

RevDate: 2019-03-26

Guo J, Liu X, Poncelet N, et al (2019)

Detection and geographic distribution of seven facultative endosymbionts in two Rhopalosiphum aphid species.

MicrobiologyOpen [Epub ahead of print].

Study of the mutualistic associations between facultative symbionts and aphids are developed only in a few models. That survey on the situation and distribution of the symbionts in a certain area is helpful to obtain clues for the acquisition and spread of them as well as their roles played in host evolution. To understand the infection patterns of seven facultative symbionts (Serratia symbiotica, Hamiltonella defensa, Regiella insecticola, Rickettsia, Spiroplasma, Wolbachia, and Arsenophonus) in Rhopalosiphum padi (Linnaeus) and Rhopalosiphum maidis (Fitch), we collected 882 R. maidis samples (37 geographical populations) from China and 585 R. padi samples (32 geographical populations) from China and Europe. Results showed that both species were widely infected with various symbionts and totally 50.8% of R. maidis and 50.1% of R. padi were multi-infected with targeted symbionts. However, very few Rhopalosiphum aphids were infected with S. symbiotica. The infection frequencies of some symbionts were related to the latitude of collecting sites, suggesting the importance of environmental factors in shaping the geographic distribution of facultative symbionts. Also, R. maidis and R. padi were infected with different H. defensa strains based on phylogenetic analysis which may be determined by host ×symbiont genotype interactions. According to our results, the ubiquitous symbionts may play important roles in the evolution of their host aphid and their impacts on adaptation of R. padi and R. maidis were discussed as well.

RevDate: 2019-05-29
CmpDate: 2019-05-29

Bing XL, Zhao DS, XY Hong (2019)

Bacterial reproductive manipulators in rice planthoppers.

Archives of insect biochemistry and physiology, 101(2):e21548.

Rice planthoppers (Hemiptera: Delphacidae) are notorious pests for rice (Oryza sativa) in Asia, posing a serious threat to rice production and grain security. Rice planthoppers harbor diverse bacterial symbionts, including Wolbachia, Cardinium, Spiroplasma, and Arsenophonus, which are known to manipulate reproduction in arthropod hosts. This microreview is to introduce current knowledge of bacterial reproductive manipulators in rice planthoppers, including their diversity, population dynamics, localization, transmission, and biological functions.

RevDate: 2019-03-29

Tolley SJA, Nonacs P, P Sapountzis (2019)

Wolbachia Horizontal Transmission Events in Ants: What Do We Know and What Can We Learn?.

Frontiers in microbiology, 10:296.

While strict vertical transmission insures the durability of intracellular symbioses, phylogenetic incongruences between hosts and endosymbionts suggest horizontal transmission must also occur. These horizontal acquisitions can have important implications for the biology of the host. Wolbachia is one of the most ecologically successful prokaryotes in arthropods, infecting an estimated 50-70% of all insect species. Much of this success is likely due to the fact that, in arthropods, Wolbachia is notorious for manipulating host reproduction to favor transmission through the female germline. However, its natural potential for horizontal transmission remains poorly understood. Here we evaluate the fundamental prerequisites for successful horizontal transfer, including necessary environmental conditions, genetic potential of bacterial strains, and means of mediating transfers. Furthermore, we revisit the relatedness of Wolbachia strains infecting the Panamanian leaf-cutting ant, Acromyrmex echinatior, and its inquiline social parasite, Acromyrmex insinuator, and compare our results to a study published more than 15 years ago by Van Borm et al. (2003). The results of this pilot study prompt us to reevaluate previous notions that obligate social parasitism reliably facilitates horizontal transfer and suggest that not all Wolbachia strains associated with ants have the same genetic potential for horizontal transmission.

RevDate: 2019-04-25
CmpDate: 2019-04-25

Fattouh N, Cazevieille C, F Landmann (2019)

Wolbachia endosymbionts subvert the endoplasmic reticulum to acquire host membranes without triggering ER stress.

PLoS neglected tropical diseases, 13(3):e0007218 pii:PNTD-D-18-01659.

The reproductive parasites Wolbachia are the most common endosymbionts on earth, present in a plethora of arthropod species. They have been introduced into mosquitos to successfully prevent the spread of vector-borne diseases, yet the strategies of host cell subversion underlying their obligate intracellular lifestyle remain to be explored in depth in order to gain insights into the mechanisms of pathogen-blocking. Like some other intracellular bacteria, Wolbachia reside in a host-derived vacuole in order to replicate and escape the immune surveillance. Using here the pathogen-blocking Wolbachia strain from Drosophila melanogaster, introduced into two different Drosophila cell lines, we show that Wolbachia subvert the endoplasmic reticulum to acquire their vacuolar membrane and colonize the host cell at high density. Wolbachia redistribute the endoplasmic reticulum, and time lapse experiments reveal tight coupled dynamics suggesting important signalling events or nutrient uptake. Wolbachia infection however does not affect the tubular or cisternal morphologies. A fraction of endoplasmic reticulum becomes clustered, allowing the endosymbionts to reside in between the endoplasmic reticulum and the Golgi apparatus, possibly modulating the traffic between these two organelles. Gene expression analyses and immunostaining studies suggest that Wolbachia achieve persistent infections at very high titers without triggering endoplasmic reticulum stress or enhanced ERAD-driven proteolysis, suggesting that amino acid salvage is achieved through modulation of other signalling pathways.

RevDate: 2019-03-19

Endersby-Harshman NM, Axford JK, AA Hoffmann (2019)

Environmental Concentrations of Antibiotics May Diminish Wolbachia infections in Aedes aegypti (Diptera: Culicidae).

Journal of medical entomology pii:5393597 [Epub ahead of print].

Wolbachia-infected Aedes aegypti (L.) mosquitoes for control of dengue transmission are being released experimentally in tropical regions of Australia, south-east Asia, and South America. To become established, the Wolbachia Hertig (Rickettsiales: Rickettsiaceae) strains used must induce expression of cytoplasmic incompatibility (CI) in matings between infected males and uninfected females so that infected females have a reproductive advantage, which will drive the infection through field populations. Wolbachia is a Rickettsia-like alphaproteobacterium which can be affected by tetracycline antibiotics. We investigated whether exposure of Wolbachia-infected mosquitoes to chlortetracycline at environmentally relevant levels during their aquatic development resulted in loss or reduction of infection in three strains, wAlbB, wMel, and wMelPop. Wolbachia density was reduced for all three strains at the tested chlortetracycline concentrations of 5 and 50 µg/liter. Two of the strains, wMel and wMelPop, showed a breakdown in CI. The wAlbB strain maintained CI and may be useful at breeding sites where tetracycline contamination has occurred. This may include drier regions where Ae. aegypti can utilize subterranean water sources and septic tanks as breeding sites.

RevDate: 2019-04-02

Portillo A, Palomar AM, de Toro M, et al (2019)

Exploring the bacteriome in anthropophilic ticks: To investigate the vectors for diagnosis.

PloS one, 14(3):e0213384 pii:PONE-D-18-28858.

OBJECTIVE: The aim of this study was to characterize the bacterial microbiome of hard ticks with affinity to bite humans in La Rioja (North of Spain).

METHODS: A total of 88 adult ticks (22 Rhipicephalus sanguineus sensu lato, 27 Haemaphysalis punctata, 30 Dermacentor marginatus and 9 Ixodes ricinus) and 120 I. ricinus nymphs (CRETAV collection, La Rioja, Spain), representing the main anthropophilic species in our environment, were subjected to a metagenomic analysis of the V3-V4 region of the 16S rRNA gene using an Illumina MiSeq platform. Data obtained with Greengenes database were refined with BLAST. Four groups of samples were defined, according to the four tick species.

RESULTS: Proteobacteria was the predominant phylum observed in all groups. Gammaproteobacteria was the most abundant class, followed by Alphaproteobacteria for R. sanguineus, H. punctata and D. marginatus but the relative abundance of reads for these classes was reversed for I. ricinus. This tick species showed more than 46% reads corresponding to 'not assigned' OTUs (Greengenes), and >97% of them corresponded to 'Candidatus Midichloriaceae' using BLAST. Within Rickettsiales, 'Candidatus Midichloria', Rickettsia, Ehrlichia, 'Candidatus Neoehrlichia' and Wolbachia were detected. I. ricinus was the most alpha-diverse species. Regarding beta-diversity, I. ricinus and H. punctata samples grouped according to their tick species but microbial communities of some R. sanguineus and D. marginatus specimens clustered together.

CONCLUSIONS: The metagenomics approach seems useful to discover the spectrum of tick-related bacteria. More studies are needed to identify and differentiate bacterial species, and to improve the knowledge of tick-borne diseases in Spain.

RevDate: 2019-04-02

Kanakala S, M Ghanim (2019)

Global genetic diversity and geographical distribution of Bemisia tabaci and its bacterial endosymbionts.

PloS one, 14(3):e0213946 pii:PONE-D-18-36930.

Bemisia tabaci is one of the most threatening pests in agriculture, causing significant losses to many important crops on a global scale. The dramatic increase and availability of sequence data for B. tabaci species complex and its bacterial endosymbionts is critical for developing emerging sustainable pest management strategies which are based on pinpointing the global diversity of this important pest and its bacterial endosymbionts. To unravel the global genetic diversity of B. tabaci species complex focusing on its associated endosymbionts, along with Israeli whitefly populations collected in this study, we combined available sequences in databases, resulting in a total of 4,253 mitochondrial cytochrome oxidase I (mtCOI) sequences from 82 countries and 1,226 16S/23S rRNA endosymbiont sequences from 32 countries that were analyzed. Using Bayesian phylogenetic analysis, we identified two new B. tabaci groups within the species complex and described the global distribution of endosymbionts within this complex. Our analyses revealed complex divergence of the different endosymbiont sequences within the species complex, with overall one Hamiltonella, two Porteria (P1 and P2), two Arsenophonus (A1 and A2), two Wolbachia (super-groups O and B), four Cardinium (C1-C4) and three Rickettsia (R1-R3) groups were identified. Our comprehensive analysis provides an updated important resource for this globally important pest and its secondary symbionts, which have been a major subject for research in last three decades.

RevDate: 2019-05-01

Balaji S, Jayachandran S, SR Prabagaran (2019)

Evidence for the natural occurrence of Wolbachia in Aedes aegypti mosquitoes.

FEMS microbiology letters, 366(6):.

Wolbachia, a Gram-negative bacterium, is widely known to be present in arthropods and nematodes. Of late, great impetus is given to employ this intracellular bacterium, as an alternative to conventional biocontrol agents for the control of mosquitoes because of its inherent ability to induce sperm-egg incompatibility, feminisation etc. By employing molecular tools, we have shown the presence of Wolbachia from Aedes aegypti mosquito population collected from Coimbatore, India by PCR amplifying the Ae. aegypti mosquito genome with Wolbachia specific 16S rRNA, wsp and ftsZ gene primers. The phylogenetic analysis of these gene sequences incorporating MLST and GenBank reference sequences has confirmed the occurrence of Wolbachia supergroup B in Ae. aegypti. In addition, qRT-PCR results have shown the dynamics of Wolbachia across the developmental stages of mosquito. The absence of Wolbachia in tetracycline-treated Ae. aegypti mosquitoes evidenced by transmission electron microscopy reinforced our finding conclusively. After confirming their persistence through generations, we have designated Wolbachia from Ae. aegypti as wAegB. In our considered view, wAegB could play a dynamic role in impeding mosquito multiplication and consequently impinging transmission of the dreadful dengue.

RevDate: 2019-05-15

Taylor MJ, von Geldern TW, Ford L, et al (2019)

Preclinical development of an oral anti-Wolbachia macrolide drug for the treatment of lymphatic filariasis and onchocerciasis.

Science translational medicine, 11(483):.

There is an urgent global need for a safe macrofilaricide drug to accelerate elimination of the neglected tropical diseases onchocerciasis and lymphatic filariasis. From an anti-infective compound library, the macrolide veterinary antibiotic, tylosin A, was identified as a hit against Wolbachia This bacterial endosymbiont is required for filarial worm viability and fertility and is a validated target for macrofilaricidal drugs. Medicinal chemistry was undertaken to develop tylosin A analogs with improved oral bioavailability. Two analogs, A-1535469 and A-1574083, were selected. Their efficacy was tested against the gold-standard second-generation tetracycline antibiotics, doxycycline and minocycline, in mouse and gerbil infection models of lymphatic filariasis (Brugia malayi and Litomosoides sigmodontis) and onchocerciasis (Onchocerca ochengi). A 1- or 2-week course of oral A-1535469 or A-1574083 provided >90% Wolbachia depletion from nematodes in infected animals, resulting in a block in embryogenesis and depletion of microfilarial worm loads. The two analogs delivered comparative or superior efficacy compared to a 3- to 4-week course of doxycycline or minocycline. A-1574083 (now called ABBV-4083) was selected for further preclinical testing. Cardiovascular studies in dogs and toxicology studies in rats and dogs revealed no adverse effects at doses (50 mg/kg) that achieved plasma concentrations >10-fold above the efficacious concentration. A-1574083 (ABBV-4083) shows potential as an anti-Wolbachia macrolide with an efficacy, pharmacology, and safety profile that is compatible with a short-term oral drug course for treating lymphatic filariasis and onchocerciasis.

RevDate: 2019-03-12

Wang J, Zhu X, Ying Z, et al (2019)

Prevalence of Dirofilaria immitis Infections In Dogs and Cats In Hainan Island/Province and Three Other Coastal Cities of China Based On Antigen Testing and PCR.

The Journal of parasitology, 105(2):199-202.

Canine and feline heartworm disease caused by Dirofilaria immitis is a serious and sometimes fatal infection transmitted by mosquitos. Little is known about the prevalence or distribution of D. immitis infection in dogs and cats on the island of Hainan island/province or coastal cities of China. The present study examined the occurrence of D. immitis infections in dogs (n = 869) and cats (n = 51) in Hainan island/province and prevalence in dogs from 3 coastal cities (Shenzhen [n = 55], Shanghai [n = 69], and Hangzhou [n = 45]) in southern and eastern China. A commercial antigen detection (AD) test and 2 PCR methods (16S ribosomal RNA and Wolbachia surface protein [ WSP] genes) were used to determine the prevalence of D. immitis from animals >6 mo old with no previous history of D. immitis preventive treatment or heartworm infection. Gene sequencing was used to confirm positive PCR samples. The AD test was not used on cat samples. Using the AD test, the prevalence in dogs was 0.5% (4/869) in Hainan island/province, 0% (0/55) in Shenzhen, 1.5% (1/69) in Shanghai, and 0% (0/45) in Hangzhou. Prevalence by 16S rRNA gene PCR was 7.4% (64/869) of dogs from Hainan island/province, 0% (0/55) in dogs from Shenzhen, 1.5% (1/69) in dogs from Shanghai, and 0% (0/45) in dogs from Hangzhou. Prevalence by WSP gene PCR in dogs was 5.3% (46/869) in Hainan island/province, 0% (0/55) in Shenzhen, 1.5% (1/69) in Shanghai, and 0% (0/45) in Hangzhou. Prevalence in the 51 cats from Hainan island/province was 9.8% and 5.9% by 16S rRNA and WSP gene PCR, respectively. The present study demonstrates that canine heartworm exposure occurs in dogs and cats in Hainan island/province and that PCR methods detected a higher prevalence than did the AD method. The 16S rRNA gene PCR detected more positive samples than did the WSP gene PCR in both dogs and cats. The 3 coastal cities had very few dogs that had evidence of D. immitis exposure.

RevDate: 2019-05-20

Brinker P, Fontaine MC, Beukeboom LW, et al (2019)

Host, Symbionts, and the Microbiome: The Missing Tripartite Interaction.

Trends in microbiology, 27(6):480-488.

Symbiosis between microbial associates and a host is a ubiquitous feature of life on earth, modulating host phenotypes. In addition to endosymbionts, organisms harbour a collection of host-associated microbes, the microbiome that can impact important host traits. In this opinion article we argue that the mutual influences of the microbiome and endosymbionts, as well as their combined influence on the host, are still understudied. Focusing on the endosymbiont Wolbachia, we present growing evidence indicating that host phenotypic effects are exerted in interaction with the remainder microbiome and the host. We thus advocate that only through an integrated approach that considers multiple interacting partners and environmental influences will we be able to gain a better understanding of host-microbe associations.

RevDate: 2019-06-10

Davydov II, Salamin N, M Robinson-Rechavi (2019)

Large-Scale Comparative Analysis of Codon Models Accounting for Protein and Nucleotide Selection.

Molecular biology and evolution, 36(6):1316-1332.

There are numerous sources of variation in the rate of synonymous substitutions inside genes, such as direct selection on the nucleotide sequence, or mutation rate variation. Yet scans for positive selection rely on codon models which incorporate an assumption of effectively neutral synonymous substitution rate, constant between sites of each gene. Here we perform a large-scale comparison of approaches which incorporate codon substitution rate variation and propose our own simple yet effective modification of existing models. We find strong effects of substitution rate variation on positive selection inference. More than 70% of the genes detected by the classical branch-site model are presumably false positives caused by the incorrect assumption of uniform synonymous substitution rate. We propose a new model which is strongly favored by the data while remaining computationally tractable. With the new model we can capture signatures of nucleotide level selection acting on translation initiation and on splicing sites within the coding region. Finally, we show that rate variation is highest in the highly recombining regions, and we propose that recombination and mutation rate variation, such as high CpG mutation rate, are the two main sources of nucleotide rate variation. Although we detect fewer genes under positive selection in Drosophila than without rate variation, the genes which we detect contain a stronger signal of adaptation of dynein, which could be associated with Wolbachia infection. We provide software to perform positive selection analysis using the new model.

RevDate: 2019-04-15
CmpDate: 2019-04-15

Idro R, Anguzu R, Ogwang R, et al (2019)

Doxycycline for the treatment of nodding syndrome (DONS); the study protocol of a phase II randomised controlled trial.

BMC neurology, 19(1):35 pii:10.1186/s12883-019-1256-z.

BACKGROUND: Nodding syndrome is a poorly understood neurological disorder of unknown aetiology, affecting several thousand children in Africa. There has been a consistent epidemiological association with infection by the filarial parasite, Onchocerca volvulus and antibodies to leiomodin and DJ-1, cross-reacting with O.volvulus proteins, have been reported. We hypothesized that nodding syndrome is a neuro-inflammatory disorder, induced by antibodies to O.volvulus or its symbiont, Wolbachia, cross-reacting with human neuron proteins and that doxycycline, which kills Onchocerca through effects on Wolbachia, may be used as treatment.

METHODS: This will be a two-arm, double-blind, placebo-controlled, randomised phase II trial of doxycycline 100 mg daily for six weeks in 230 participants. Participants will be patients' ages≥8 years with nodding syndrome. They will receive standard of care supportive treatment. All will be hospitalised for 1-2 weeks during which time baseline measurements including clinical assessments, EEG, cognitive and laboratory testing will be performed and antiepileptic drug doses rationalised. Participants will then be randomised to either oral doxycycline (Azudox®, Kampala Pharmaceutical Industries) 100 mg daily or placebo. Treatment will be initiated in hospital and continued at home. Participants will be visited at home at 2, 4 and 6 weeks for adherence monitoring. Study outcomes will be assessed at 6, 12, 18 and 24-month visits. Analysis will be by intention to treat. The primary efficacy outcome measure will be the proportion of patients testing positive and the levels or titires of antibodies to host neuron proteins (HNPs) and/or leiomodin at 24 months. Secondary outcome measures will include effect of the intervention on seizure control, inflammatory markers, cognitive function, disease severity and quality of life.

DISCUSSION: This trial postulates that targeting O.volvulus through drugs which kill Wolbachia can modify the pathogenic processes in nodding syndrome and improve outcomes. Findings from this study are expected to substantially improve the understanding and treatment of nodding syndrome.

TRIAL REGISTRATION: Registered with clinicaltrials.gov ID: NCT02850913 on 1st August, 2016.

RevDate: 2019-04-26

Kwon M, Seo SS, Kim MK, et al (2019)

Compositional and Functional Differences between Microbiota and Cervical Carcinogenesis as Identified by Shotgun Metagenomic Sequencing.

Cancers, 11(3): pii:cancers11030309.

Recent studies have reported the potential role of microbiomes in cervical disease. However, little is known about the microbiome composition and function in cervical carcinogenesis. We aimed to identify the compositional and functional alterations of cervical microbiomes in cases of cervical carcinogenesis of Korean women using shotgun metagenomic sequencing. In this study, using shotgun sequencing, we sequenced the cervical metagenomes of cervical intraneoplasia 2/3 (n = 17), cervical cancer (n = 12), and normal controls (n = 18) to identify the microbial abundances and enriched metabolic functions in cervical metagenomes. At the genus level, the microbiota of cervical cancer were differentially enriched with genera Alkaliphilus, Pseudothermotoga, and Wolbachia. Cervical intraepithelial neoplasia (CIN) 2/3 were enriched with Lactobacillus, Staphylococcus, and Candidatus Endolissoclinum. The normal group was enriched with Pseudoalteromonas and Psychrobacter. Further characterization of the functionalities of the metagenomes may suggest that six Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) that are involved in 10 pathways are associated with an increased risk of CIN2/3 and cervical cancer. Specifically, cervical metagenomes were enriched in the course of peptidoglycan synthesis and depleted by dioxin degradation and 4-oxalocrotonate tautomerase. The Cluster of Orthologous Groups (COG) category 'Defense mechanisms' was depleted in cervical cancer patients. Our findings based on shotgun metagenomic sequencing suggest that cervical microbiome community compositions and their metagenomics profiles differed between cervical lesions and normal subjects. Future studies should have larger sample sizes and/or aggregate their results to have sufficient power to detect reproducible and significant associations.

RevDate: 2019-04-05
CmpDate: 2019-04-05

Reveillaud J, Bordenstein SR, Cruaud C, et al (2019)

The Wolbachia mobilome in Culex pipiens includes a putative plasmid.

Nature communications, 10(1):1051 pii:10.1038/s41467-019-08973-w.

Wolbachia is a genus of obligate intracellular bacteria found in nematodes and arthropods worldwide, including insect vectors that transmit dengue, West Nile, and Zika viruses. Wolbachia's unique ability to alter host reproductive behavior through its temperate bacteriophage WO has enabled the development of new vector control strategies. However, our understanding of Wolbachia's mobilome beyond its bacteriophages is incomplete. Here, we reconstruct near-complete Wolbachia genomes from individual ovary metagenomes of four wild Culex pipiens mosquitoes captured in France. In addition to viral genes missing from the Wolbachia reference genome, we identify a putative plasmid (pWCP), consisting of a 9.23-kbp circular element with 14 genes. We validate its presence in additional Culex pipiens mosquitoes using PCR, long-read sequencing, and screening of existing metagenomes. The discovery of this previously unrecognized extrachromosomal element opens additional possibilities for genetic manipulation of Wolbachia.

RevDate: 2019-03-07

Pagel L, Bultman T, Górzyńska K, et al (2019)

Botanophila flies, vectors of Epichloë fungal spores, are infected by Wolbachia.

Mycology, 10(1):1-5 pii:1515119.

Epichloë fungi are endophytes within grasses that can form stromata on culms of their hosts. Botanophila flies visit the stromata for egg laying and in the process can vector spermatial spores, thereby cross fertilising the fungus. Following egg hatch, larval flies consume fungal tissue and spores. Thus, Epichloë individuals with traits that limit larval consumption could be at a selective advantage. We assessed Botanophila fly larvae from sites within the United States and Europe for infection by the bacterial sexual parasite Wolbachia through amplification of the Wolbachia surface protein gene (wsp). Nearly 70% of fly larvae in our samples were infected by Wolbachia. This is the first record of infection by Wolbachia within Botanophila and could have far reaching effects on not only the fly host, but also the Epichloë fungi upon which Botanophila feeds as well as the grass host within which the fungi live. For example, infection by Wolbachia could limit consumption of Epichloë spores by Botanophila larvae if the bacteria promoted premature larval death.

RevDate: 2019-03-01

Onder Z, Ciloglu A, Duzlu O, et al (2019)

Molecular detection and identification of Wolbachia endosymbiont in fleas (Insecta: Siphonaptera).

Folia microbiologica pii:10.1007/s12223-019-00692-5 [Epub ahead of print].

The aim of this study was to determine the presence and prevalence of Wolbachia bacteria in natural population of fleas (Insecta: Siphonaptera) in Turkey, and to exhibit the molecular characterization and the phylogenetic reconstruction at the positive isolates with other species in GenBank, based on 16S rDNA sequences. One hundred twenty-four flea samples belonging to the species Ctenocephalides canis, C. felis, and Pulex irritans were collected from animal shelters in Kayseri between January and August 2017. All flea species were individually screened for the presence of Wolbachia spp. by polymerase chain reaction (PCR) targeting the 16S ribosomal RNA gene. According to PCR analyses, Wolbachia spp. were found prevalent in C. canis and P. irritans fleas, while it was not detected in the C. felis species. Totally, 20 isolates were purified from agarose gel and sequenced with the same primers for molecular characterization and phylogenetic analyses. The sequence analyses revealed 17 polymorphic sites and 2 genetically different Wolbachia isolates, representing two different haplotypes in two flea species. The distribution patterns, molecular characterization, and phylogenetic status of Wolbachia spp. of fleas in Turkey are presented for the first time with this study. Understanding of the role of Wolbachia in vector biology may provide information for developing Wolbachia-based biological control tools.

RevDate: 2019-04-26

Fortin M, Meunier J, Laverré T, et al (2019)

Joint effects of group sex-ratio and Wolbachia infection on female reproductive success in the terrestrial isopod Armadillidium vulgare.

BMC evolutionary biology, 19(1):65 pii:10.1186/s12862-019-1391-6.

BACKGROUND: In species that reproduce with sexual reproduction, males and females often have opposite strategies to maximize their own fitness. For instance, males are typically expected to maximize their number of mating events, whereas an excessive number of mating events can be costly for females. Although the risk of sexual harassment by males and resulting costs for females are expected to increase with the proportion of males, it remains unknown whether and how parasitic distorters of a host population's sex-ratio can shape this effect on the fitness of females. Here, we addressed this question using Armadillidium vulgare and its parasite Wolbachia that alters the sex-ratio of a population. We set up Wolbachia-free and Wolbachia-infected females in experimental groups exhibiting 100, 80, 50% or 20% females for 1 year, during which we measured changes in survival, fertility and fecundity.

RESULTS: Wolbachia infection shaped the effects of both population sex-ratio and reproductive season on female fecundity. Compared to Wolbachia-free females, Wolbachia-infected females were less likely to be gravid in populations exhibiting an excess of females and did not exhibit the otherwise negative effect of seasons on this likelihood. Group sex-ratio and Wolbachia infection have independent effects on other measured traits. Male-biased populations had females both exhibiting the lowest survival rate after 6 months and producing the smallest number of offspring, independent of Wolbachia infection. Conversely, Wolbachia-infected females had the lowest likelihood of producing at least one offspring, independent of group sex-ratio. Wolbachia infection had no effect on female survival rate.

CONCLUSIONS: We demonstrated that male-biased sex-ratio and the presence of Wolbachia are costly for females due to sexual harassment by males and bacterial infection, respectively. Interestingly, Wolbachia infection triggers another negative effect. This effect does not come from an excess of males and its associated sexual harassment of females but instead from a lack of males and the associated risk for females of remaining unmated. Overall, these findings highlight the importance of social pressures and infection on female fitness and provide insights into our general understanding of the joint and opposite effects of these two parameters in the evolution of reproductive strategies.

RevDate: 2019-04-02
CmpDate: 2019-03-29

von Geldern TW, Morton HE, Clark RF, et al (2019)

Discovery of ABBV-4083, a novel analog of Tylosin A that has potent anti-Wolbachia and anti-filarial activity.

PLoS neglected tropical diseases, 13(2):e0007159 pii:PNTD-D-18-01874.

There is a significant need for improved treatments for onchocerciasis and lymphatic filariasis, diseases caused by filarial worm infection. In particular, an agent able to selectively kill adult worms (macrofilaricide) would be expected to substantially augment the benefits of mass drug administration (MDA) with current microfilaricides, and to provide a solution to treatment of onchocerciasis / loiasis co-infection, where MDA is restricted. We have identified a novel macrofilaricidal agent, Tylosin A (TylA), which acts by targeting the worm-symbiont Wolbachia bacterium. Chemical modification of TylA leads to improvements in anti-Wolbachia activity and oral pharmacokinetic properties; an optimized analog (ABBV-4083) has been selected for clinical evaluation.

RevDate: 2019-02-28

Staunton KM, Yeeles P, Townsend M, et al (2019)

Trap Location and Premises Condition Influences on Aedes aegypti (Diptera: Culicidae) Catches Using Biogents Sentinel Traps During a 'Rear and Release' Program: Implications for Designing Surveillance Programs.

Journal of medical entomology pii:5366979 [Epub ahead of print].

As the incidence of arboviral diseases such as dengue, Zika, chikungunya, and yellow fever increases globally, controlling their primary vector, Aedes aegypti (L.) (Diptera: Culicidae), is of greater importance than ever before. Mosquito control programs rely heavily on effective adult surveillance to ensure methodological efficacy. The Biogents Sentinel (BGS) trap is the gold standard for surveilling adult Aedes mosquitoes and is commonly deployed worldwide, including during modern 'rear and release' programs. Despite its extensive use, few studies have directly assessed environmental characteristics that affect BGS trap catches, let alone how these influences change during 'rear and release' programs. We assessed male and female Ae. aegypti spatial stability, as well as premises condition and trap location influences on BGS trap catches, as part of Debug Innisfail 'rear and release' program in northern Australia. We found similar trends in spatial stability of male and female mosquitoes at both weekly and monthly resolutions. From surveillance in locations where no males were released, reduced catches were found at premises that contained somewhat damaged houses and unscreened properties. In addition, when traps were located in areas that were unsheltered, more than 10 m from commonly used sitting areas or more visually complex catches were also negatively affected. In locations where males were released, we found that traps in treatment sites, relative to control sites, displayed increased catches in heavily shaded premises and were inconsistently influenced by differences in house sets and building materials. Such findings have valuable implications for a range of Ae. aegypti surveillance programs.

RevDate: 2019-05-23
CmpDate: 2019-05-23

Bykov RА, Yudina MA, Gruntenko NE, et al (2019)

Prevalence and genetic diversity of Wolbachia endosymbiont and mtDNA in Palearctic populations of Drosophila melanogaster.

BMC evolutionary biology, 19(Suppl 1):48 pii:10.1186/s12862-019-1372-9.

BACKGROUND: Maternally inherited Wolbachia symbionts infect D. melanogaster populations worldwide. Infection rates vary greatly. Genetic diversity of Wolbachia in D. melanogaster can be subdivided into several closely related genotypes coinherited with certain mtDNA lineages. mtDNA haplotypes have the following global distribution pattern: mtDNA clade I is mostly found in North America, II and IV in Africa, III in Europe and Africa, V in Eurasia, VI is global but very rare, and VIII is found in Asia. The wMel Wolbachia genotype is predominant in D. melanogaster populations. However, according to the hypothesis of global Wolbachia replacement, the wMelCS genotype was predominant before the XX century when it was replaced by the wMel genotype. Here we analyse over 1500 fly isolates from the Palearctic region to evaluate the prevalence, genetic diversity and distribution pattrern of the Wolbachia symbiont, occurrence of mtDNA variants, and finally to discuss the Wolbachia genotype global replacement hypothesis.

RESULTS: All studied Palearctic populations of D. melanogaster were infected with Wolbachia at a rate of 33-100%. We did not observe any significant correlation between infection rate and longitude or latitude. Five previously reported Wolbachia genotypes were found in Palearctic populations with a predominance of the wMel variant. The mtDNA haplotypes of the I_II_III clade and V clade were prevalent in Palearctic populations. To test the recent Wolbachia genotype replacement hypothesis, we examined three genomic regions of CS-like genotypes. Low genetic diversity was observed, only two haplotypes of the CS genotypes with a 'CCG' variant predominance were found.

CONCLUSION: The results of our survey of Wolbachia infection prevalence and genotype diversity in Palearctic D. melanogaster populations confirm previous studies. Wolbachia is ubiquitous in the Palearctic region. The wMel genotype is dominant with local occurrence of rare genotypes. Together with variants of the V mtDNA clade, the variants of the 'III+' clade are dominant in both infected and uninfected flies of Palearctic populations. Based on our data on Wolbachia and mtDNA in different years in some Palearctic localities, we can conclude that flies that survive the winter make the predominant symbiont contribution to the subsequent generation. A comprehensive overview of mtDNA and Wolbachia infection of D. melanogaster populations worldwide does not support the recent global Wolbachia genotype replacement hypothesis. However, we cannot exclude wMelCS genotype rate fluctuations in the past.

RevDate: 2019-03-13
CmpDate: 2019-03-13

Cândido EL, Silva UMD, LPG Cavalcanti (2019)

New record and extended geographical distribution of Aedes fluviatilis (Lutz, 1904) in Ceará, northeastern Brazil.

Revista da Sociedade Brasileira de Medicina Tropical, 52:e20180286 pii:S0037-86822019000100616.

INTRODUCTION: Aedes fluviatilis(Lutz, 1904) is considered a potential vector of yellow fever and dengue viruses and is naturally infected by Wolbachia.

METHODS: In March 2018, during a field activity in the municipality of Saboeiro, 163 mosquito larvae were collected in a dammed area of the Jaguaribe River.

RESULTS: Of the larvae collected, 143 (87.7%) were identified asAe. fluviatilis.

CONCLUSIONS: We report the first documentation of Ae. fluviatilis in the municipality of Saboeiro, northeastern Brazil. It is important to conduct additional entomological surveys to characterize the local Culicidae fauna. Ignoring the presence and dispersion of this vector could be a public health risk.

RevDate: 2019-04-14

Bagheri Z, Talebi AA, Asgari S, et al (2019)

Wolbachia induce cytoplasmic incompatibility and affect mate preference in Habrobracon hebetor to increase the chance of its transmission to the next generation.

Journal of invertebrate pathology, 163:1-7.

Wolbachia are common intracellular bacteria that are generally found in arthropods, including a high proportion of insects and also some nematodes. This intracellular symbiont can affect sex ratio with a variety of reproductive anomalies in the host, including cytoplasmic incompatibility (CI) in haplodiploids. In this study, we questioned if the parasitoid wasp, Habrobracon hebetor (Hym.: Braconidae), an important biological control agent of many lepidopteran larvae, is infected with Wolbachia. To test this, DNA was extracted from adult insects and subjected to PCR using specific primers to Wolbachia target genes. The results showed a high rate of Wolbachia infection in this parasitoid wasp. To determine the biological function of Wolbachia in H. hebetor, we removed this bacterium from the wasps using antibiotic treatment (cured wasps). Results of crossing experiments revealed that Wolbachia induced CI in H. hebetor in which cured females crossed with infected males produced only males, while both male and female progeny were observed for other crosses. Also, we showed that the presence of Wolbachia in females increased fecundity and female offspring of this parasitoid wasp. The presence of Wolbachia in the males had no significant effect on fecundity and female production, but might have incurred costs. We also investigated the effect of Wolbachia on mate choice and found that Wolbachia affects mating behavior of H. hebetor. Together, we showed that Wolbachia induces CI in H. hebetor and affects host mating behavior in favor of its transmission. Wolbachia utilize these strategies to increase the frequency of infected females in the host population.

RevDate: 2019-02-24

Singhal K, S Mohanty (2019)

Genome organisation and comparative genomics of four novel Wolbachia genome assemblies from Indian Drosophila host.

Functional & integrative genomics pii:10.1007/s10142-019-00664-5 [Epub ahead of print].

Wolbachia has long been known to share an endosymbiotic relationship with its host as an obligate intracellular organism. Wolbachia diversity as different supergroups is found to be host-specific in most cases except a few, where the host species is seen to accommodate multiple strains. Besides, the Wolbachia genome must have undergone several changes in response to the evolving host genome in order to adapt and establish a strong association with its host, thus making a distinctive Wolbachia-host alliance. The present study focusses on four novel genome assembly and genome-wide sequence variations of Indian Wolbachia strains, i.e. wMel and wRi isolated from two different Drosophila hosts. The genome assembly has an average size of ~ 1.1 Mb and contains ~ 1100 genes, which is comparable with the previously sequenced Wolbachia genomes. The comparative genomics analysis of these genomes and sequence-wide comparison of some functionally significant genes, i.e. ankyrin repeats, Wsp and T4SS, highlight their sequence similarities and dissimilarities, further supporting the strain-specific association of Wolbachia to its host. Interestingly, some of the sequence variations are also found to be restricted to only Indian Wolbachia strains. Further analysis of prophage and their flanking regions in the Wolbachia genome reveals the presence of several functional genes which may assist the phage to reside inside the bacterial host, thus providing a trade-off for the endosymbiont-host association. Understanding this endosymbiont genome in different eco-geographical conditions has become imperative for the recent use of Wolbachia in medical entomology as a vector-control agent.

RevDate: 2019-04-18

Newton ILG, BE Slatko (2019)

Symbiosis Comes of age at the 10th Biennial Meeting of Wolbachia Researchers.

Applied and environmental microbiology pii:AEM.03071-18 [Epub ahead of print].

Wolbachia pipientis is an alpha-proteobacterial, obligate intracellular microbe and arguably the most successful infection on our planet, colonizing 40-60% of insect species. Wolbachia are also present in most, but not all, filarial nematodes where they are obligate mutualists and are the targets for anti-filarial drug discovery. Although Wolbachia are related to important human pathogens they do not infect mammals, but instead are well known for their reproductive manipulations of insect populations, inducing the following phenotypes: male-killing, feminization, parthenogenesis induction, or cytoplasmic incompatibility (CI). The most common of these, CI, results in a sperm-egg incompatibility and increases the relative fecundity of infected females in a population. In the last decade, Wolbachia have also been shown to provide a benefit to insects, where the infection can inhibit RNA virus replication within the host. Wolbachia cannot be cultivated outside of host cells and no genetic tools are available in the symbiont, limiting approaches available to its study. This means that many questions fundamental to our understanding of Wolbachia basic biology remained unknown for decades. The tenth biennial international Wolbachia conference, "Wolbachia Evolution, Ecology, Genomics and Cell Biology: A Chronicle of the Most Ubiquitous Symbiont", was held on June 17-22, 2018, Salem, MA USA. In the review below we highlight the new science presented at the meeting, link it to prior efforts to answer these questions across the Wolbachia genus, and the importance to the field of symbiosis. The topics covered in this review are based on the presentations at the conference.

RevDate: 2019-05-29
CmpDate: 2019-05-29

Martínez-Rodríguez P, Rolán-Alvarez E, Del Mar Pérez-Ruiz M, et al (2019)

Geographic and Temporal Variation of Distinct Intracellular Endosymbiont Strains of Wolbachia sp. in the Grasshopper Chorthippus parallelus: a Frequency-Dependent Mechanism?.

Microbial ecology, 77(4):1036-1047.

Wolbachia is an intracellular endosymbiont that can produce a range of effects on host fitness, but the temporal dynamics of Wolbachia strains have rarely been experimentally evaluated. We compare interannual strain frequencies along a geographical region for understanding the forces that shape Wolbachia strain frequency in natural populations of its host, Chorthippus parallelus (Orthoptera, Acrididae). General linear models show that strain frequency changes significantly across geographical and temporal scales. Computer simulation allows to reject the compatibility of the observed patterns with either genetic drift or sampling errors. We use consecutive years to estimate total Wolbachia strain fitness. Our estimation of Wolbachia fitness is significant in most cases, within locality and between consecutive years, following a negatively frequency-dependent trend. Wolbachia spp. B and F strains show a temporal pattern of variation that is compatible with a negative frequency-dependent natural selection mechanism. Our results suggest that such a mechanism should be at least considered in future experimental and theoretical research strategies that attempt to understand Wolbachia biodiversity.

RevDate: 2019-05-05

Showler AJ, Kubofcik J, Ricciardi A, et al (2019)

Differences in the Clinical and Laboratory Features of Imported Onchocerciasis in Endemic Individuals and Temporary Residents.

The American journal of tropical medicine and hygiene, 100(5):1216-1222.

Many parasitic infections have different presenting features in endemic individuals (ENDs) and immunologically naive temporary residents (TRs). Temporary residents with loiasis often display acute symptoms and hypereosinophilia, in contrast to a parasite-induced subclinical state in chronically infected ENDs. Few studies have examined differences in ENDs and TRs infected with the related filarial parasite Onchocerca volvulus. We identified 40 TRs and 36 ENDs with imported onchocerciasis at the National Institutes of Health between 1976 and 2016. All study subjects received an extensive pretreatment medical history, physical examination, and laboratory investigations. We performed additional parasite-specific serologic testing on stored patient sera. Asymptomatic infection occurred in 12.5% of TRs and no ENDs (P = 0.06). Papular dermatitis was more common in TRs (47.5% versus 2.7%, P < 0.001), whereas more pigmentation changes occurred in ENDs (41.7% versus 15%, P = 0.01). Only endemic patients reported visual disturbance (13% versus 0%, P = 0.03). One TR (3.3%) had onchocercal eye disease, compared with 22.6% of ENDs (P = 0.053). Absolute eosinophil counts (AECs) were similar in ENDs and TRs (P = 0.5), and one-third of subjects had a normal AEC. Endemic individuals had higher filarial-specific IgG4 and were more likely to be positive for IgG4 antibodies to Ov-16. Temporary residents and ENDs with imported O. volvulus infection presented with different dermatologic manifestations; ocular involvement occurred almost exclusively in ENDs. Unlike Loa loa, clinical differences appear not to be eosinophil-mediated and may reflect chronicity, intensity of infection, or the presence of Wolbachia in O. volvulus.

RevDate: 2019-02-12

Chegeni TN, M Fakhar (2019)

Promising role of Wolbachia as anti-parasitic drug target and eco-friendly biocontrol agent.

Recent patents on anti-infective drug discovery pii:PRI-EPUB-96563 [Epub ahead of print].

BACKGROUND: Wolbachia is the most common endosymbiotic bacteria in insect-borne parasites and it is the most common reproductive parasite in the world. Wolbachia has been found worldwide in numerous arthropod and parasite species, including: insects, terrestrial isopods, spiders, mites and filarial nematodes. There is a complicated relationship between Wolbachia and its hosts and in some cases, they create a mutual relationship instead of a parasitic relationship. Some species are not able to reproduce in the absence of infection with Wolbachia. Thus, use of existing strains of Wolbachia bacteria offers a potential strategy for control the population of mosquitoes and other pests and diseases.

METHODS: We searched ten databases and reviewed published papers regarding the role of Wolbachia as promising drug target and emerging biological control agent of parasitic diseases between 1996 and 2017 (22 years) were considered eligible. Also, in the current study several patents (WO008652), (US7723062), (US 0345249 A1) were reviewed.

RESULTS: Endosymbiotic Wolbachia bacteria, which is inherited from mothers, is transmitted to mosquitoes and interfere with pathogen transmission. They can change the reproduction of their host. Wolbachia is transmitted through the cytoplasm of eggs and have evolved different mechanisms for manipulating reproduction of its hosts, including induction of reproductive incompatibility, parthenogenesis, and feminization. Wolbachia extensive effects on reproduction and host fitness have made Wolbachia the issue of growing attention as a potential biocontrol agent.

CONCLUSION: Wolbachia has opened a new window to design costly, potent and eco-friendly for effective treatment and elimination of vector-borne parasitic diseases.

RevDate: 2019-02-12

Augustinos AA, Moraiti CA, Drosopoulou E, et al (2019)

Old residents and new arrivals of Rhagoletis species in Europe.

Bulletin of entomological research pii:S0007485319000063 [Epub ahead of print].

The genus Rhagoletis (Diptera: Tephritidae) comprises more than 65 species distributed throughout Europe, Asia and America, including many species of high economic importance. Currently, there are three Rhagoletis species that infest fruits and nuts in Europe. The European cherry fruit fly, Rhagoletis cerasi (may have invaded Europe a long time ago from the Caucasian area of West Asia), and two invasive species (recently introduced from North America): the eastern American cherry fruit fly, R. cingulata, and the walnut husk fly, R. completa. The presence of different Rhagoletis species may enhance population dynamics and establish an unpredictable economic risk for several fruit and nut crops in Europe. Despite their excessive economic importance, little is known on population dynamics, genetics and symbiotic associations for making sound pest control decisions in terms of species-specific, environmental friendly pest control methods. To this end, the current paper (a) summarizes recently accumulated genetic and population data for the European Rhagoletis species and their association with the endosymbiont Wolbachia pipientis, and (b) explores the possibility of using the current knowledge for implementing the innovative biological control methods of sterile insect technique and incompatible insect technique.

RevDate: 2019-04-03
CmpDate: 2019-04-03

Ju H, Zhu D, M Qiao (2019)

Effects of polyethylene microplastics on the gut microbial community, reproduction and avoidance behaviors of the soil springtail, Folsomia candida.

Environmental pollution (Barking, Essex : 1987), 247:890-897.

Microplastics (MPs) are an emerging contaminant and are confirmed to be ubiquitous in the environment. Adverse effects of MPs on aquatic organisms have been widely studied, whereas little research has focused on soil invertebrates. We exposed the soil springtail Folsomia candida to artificial soils contaminated with polyethylene MPs (<500 μm) for 28 d to explore the effects of MPs on avoidance, reproduction, and gut microbiota. Springtails exhibited avoidance behaviors at 0.5% and 1% MPs (w/w in dry soil), and the avoidance rate was 59% and 69%, respectively. Reproduction was inhibited when the concentration of MPs reached 0.1% and was reduced by 70.2% at the highest concentration of 1% MPs compared to control. The half-maximal effective concentration (EC50) value based on reproduction for F. candida was 0.29% MPs. At concentrations of 0.5% dry weight in the soil, MPs significantly altered the microbial community and decreased bacterial diversity in the springtail gut. Specifically, the relative abundance of Wolbachia significantly decreased while the relative abundance of Bradyrhizobiaceae, Ensifer and Stenotrophomonas significantly increased. Our results demonstrated that MPs exerted a significant toxic effect on springtails and can change their gut microbial community. This can provide useful information for risk assessment of MPs in terrestrial ecosystems.

RevDate: 2019-03-29

Jacobs RT, Lunde CS, Freund YR, et al (2019)

Boron-Pleuromutilins as Anti- Wolbachia Agents with Potential for Treatment of Onchocerciasis and Lymphatic Filariasis.

Journal of medicinal chemistry, 62(5):2521-2540.

A series of pleuromutilins modified by introduction of a boron-containing heterocycle on C(14) of the polycyclic core are described. These analogs were found to be potent anti- Wolbachia antibiotics and, as such, may be useful in the treatment of filarial infections caused by Onchocerca volvulus, resulting in Onchocerciasis or river blindness, or Wuchereria bancrofti and Brugia malayi and related parasitic nematodes resulting in lymphatic filariasis. These two important neglected tropical diseases disproportionately impact patients in the developing world. The lead preclinical candidate compound containing 7-fluoro-6-oxybenzoxaborole (15, AN11251) was shown to have good in vitro anti- Wolbachia activity and physicochemical and pharmacokinetic properties providing high exposure in plasma. The lead was effective in reducing the Wolbachia load in filarial worms following oral administration to mice.

RevDate: 2019-02-27
CmpDate: 2019-02-18

Simo G, Kanté ST, Madinga J, et al (2019)

Molecular identification of Wolbachia and Sodalis glossinidius in the midgut of Glossina fuscipes quanzensis from the Democratic Republic of Congo.

Parasite (Paris, France), 26:5.

During the last 30 years, investigations on the microbiome of different tsetse species have generated substantial data on the bacterial flora of these cyclical vectors of African trypanosomes, with the overarching goal of improving the control of trypanosomiases. It is in this context that the presence of Wolbachia and Sodalis glossinidius was studied in wild populations of Glossina fuscipes quanzensis from the Democratic Republic of Congo. Tsetse flies were captured with pyramidal traps. Of the 700 Glossina f. quanzensis captured, 360 were dissected and their midguts collected and analyzed. Sodalis glossinidius and Wolbachia were identified by PCR. The Wolbachia-positive samples were genetically characterized with five molecular markers. PCR revealed 84.78% and 15.55% midguts infected by Wolbachia and S. glossinidius, respectively. The infection rates varied according to capture sites. Of the five molecular markers used to characterize Wolbachia, only the fructose bis-phosphate aldolase gene was amplified for about 60% of midguts previously found with Wolbachia infections. The sequencing results confirmed the presence of Wolbachia and revealed the presence of S. glossinidius in the midgut of Glossina f. quanzensis. A low level of midguts were naturally co-infected by both bacteria. The data generated in this study open a framework for investigations aimed at understanding the contribution of these symbiotic microorganisms to the vectorial competence of Glossina fuscipes quanzensis.

RevDate: 2019-05-02
CmpDate: 2019-03-22

Horváth G, Garamszegi LZ, Bereczki J, et al (2019)

Roll with the fear: environment and state dependence of pill bug (Armadillidium vulgare) personalities.

Die Naturwissenschaften, 106(3-4):7 pii:10.1007/s00114-019-1602-4.

Most studies on animal personality evaluate individual mean behaviour to describe individual behavioural strategy, while often neglecting behavioural variability on the within-individual level. However, within-individual behavioural plasticity (variation induced by environment) and within-individual residual variation (regulatory behavioural precision) are recognized as biologically valid components of individual behaviour, but the evolutionary ecology of these components is still less understood. Here, we tested whether behaviour of common pill bugs (Armadillidium vulgare) differs on the among- and within-individual level and whether it is affected by various individual specific state-related traits (sex, size and Wolbachia infection). To this aim, we assayed risk-taking in familiar vs. unfamiliar environments 30 times along 38 days and applied double modelling statistical technique to handle the complex hierarchical structure for both individual-specific trait means and variances. We found that there are significant among-individual differences not only in mean risk-taking behaviour but also in environment- and time-induced behavioural plasticity and residual variation. Wolbachia-infected individuals took less risk than healthy conspecifics; in addition, individuals became more risk-averse with time. Residual variation decreased with time, and individuals expressed higher residual variation in the unfamiliar environment. Further, sensitization was stronger in females and in larger individuals in general. Our results suggest that among-individual variation, behavioural plasticity and residual variation are all (i) biologically relevant components of an individual's behavioural strategy and (ii) responsive to changes in environment or labile state variables. We propose pill bugs as promising models for personality research due to the relative ease of getting repeated behavioural measurements.

RevDate: 2019-05-20
CmpDate: 2019-05-20

Kampfraath AA, Klasson L, Anvar SY, et al (2019)

Genome expansion of an obligate parthenogenesis-associated Wolbachia poses an exception to the symbiont reduction model.

BMC genomics, 20(1):106 pii:10.1186/s12864-019-5492-9.

BACKGROUND: Theory predicts that dependency within host-endosymbiont interactions results in endosymbiont genome size reduction. Unexpectedly, the largest Wolbachia genome was found in the obligate, parthenogenesis-associated wFol. In this study, we investigate possible processes underlying this genome expansion by comparing a re-annotated wFol genome to other Wolbachia genomes. In addition, we also search for candidate genes related to parthenogenesis induction (PI).

RESULTS: Within wFol, we found five phage WO regions representing 25.4% of the complete genome, few pseudogenized genes, and an expansion of DNA-repair genes in comparison to other Wolbachia. These signs of genome conservation were mirrored in the wFol host, the springtail F. candida, which also had an expanded DNA-repair gene family and many horizontally transferred genes. Across all Wolbachia genomes, there was a strong correlation between gene numbers of Wolbachia strains and their hosts. In order to identify genes with a potential link to PI, we assembled the genome of an additional PI strain, wLcla. Comparisons between four PI Wolbachia, including wFol and wLcla, and fourteen non-PI Wolbachia yielded a small set of potential candidate genes for further investigation.

CONCLUSIONS: The strong similarities in genome content of wFol and its host, as well as the correlation between host and Wolbachia gene numbers suggest that there may be some form of convergent evolution between endosymbiont and host genomes. If such convergent evolution would be strong enough to overcome the evolutionary forces causing genome reduction, it would enable expanded genomes within long-term obligate endosymbionts.

RevDate: 2019-05-02
CmpDate: 2019-05-02

Buchman A, Gamez S, Li M, et al (2019)

Engineered resistance to Zika virus in transgenic Aedes aegypti expressing a polycistronic cluster of synthetic small RNAs.

Proceedings of the National Academy of Sciences of the United States of America, 116(9):3656-3661.

Recent Zika virus (ZIKV) outbreaks have highlighted the necessity for development of novel vector control strategies to combat arboviral transmission, including genetic versions of the sterile insect technique, artificial infection with Wolbachia to reduce population size and/or vectoring competency, and gene drive-based methods. Here, we describe the development of mosquitoes synthetically engineered to impede vector competence to ZIKV. We demonstrate that a polycistronic cluster of engineered synthetic small RNAs targeting ZIKV is expressed and fully processed in Aedes aegypti, ensuring the formation of mature synthetic small RNAs in the midgut where ZIKV resides in the early stages of infection. Critically, we demonstrate that engineered Ae. aegypti mosquitoes harboring the anti-ZIKV transgene have significantly reduced viral infection, dissemination, and transmission rates of ZIKV. Taken together, these compelling results provide a promising path forward for development of effective genetic-based ZIKV control strategies, which could potentially be extended to curtail other arboviruses.

RevDate: 2019-05-13
CmpDate: 2019-05-13

Odeniran PO, Macleod ET, Ademola IO, et al (2019)

Endosymbionts interaction with trypanosomes in Palpalis group of Glossina captured in southwest Nigeria.

Parasitology international, 70:64-69.

Glossina species epidemiological studies were conducted in "fly-belt" endemic zone of southwest Nigeria. Two major study areas were identified and four Nzi traps were set in each site for tsetse collection. This study was conducted to determine the prevalence of endosymbionts (Wigglesworthia glossinidia, Sodalis glossinidius and Wolbachia) in natural field-trapped populations of G. p. palpalis and G. tachinoides and investigate the corresponding interactions with African trypanosomes. A total of 64 tsetse flies were collected, these included G. p. palpalis (n = 28) and G. tachinoides (n = 36). Trypanosome infection and endosymbionts of these flies were determined using polymerase chain reaction (PCR) amplification. The infection rates of W. glossinidia was 100.0% in both species, no flies were positive for Wolbachia. Sodalis glossinidius prevalence was similar between the two-tsetse species, with G. p. palpalis and G. tachinoides showing prevalence of 35.7% (95%CI: 20.7-54.2) and 27.8% (95%CI: 15.9-44.0) respectively. No relationship was found between the endosymbionts and trypanosomes in trapped tsetse flies. More studies are needed to enhance the potential control interventions mediated by endosymbionts to reduce parasitic infections.

RevDate: 2019-04-11

Sinha A, Li Z, Sun L, et al (2019)

Complete Genome Sequence of the Wolbachia wAlbB Endosymbiont of Aedes albopictus.

Genome biology and evolution, 11(3):706-720.

Wolbachia, an alpha-proteobacterium closely related to Rickettsia, is a maternally transmitted, intracellular symbiont of arthropods and nematodes. Aedes albopictus mosquitoes are naturally infected with Wolbachia strains wAlbA and wAlbB. Cell line Aa23 established from Ae. albopictus embryos retains only wAlbB and is a key model to study host-endosymbiont interactions. We have assembled the complete circular genome of wAlbB from the Aa23 cell line using long-read PacBio sequencing at 500× median coverage. The assembled circular chromosome is 1.48 megabases in size, an increase of more than 300 kb over the published draft wAlbB genome. The annotation of the genome identified 1,205 protein coding genes, 34 tRNA, 3 rRNA, 1 tmRNA, and 3 other ncRNA loci. The long reads enabled sequencing over complex repeat regions which are difficult to resolve with short-read sequencing. Thirteen percent of the genome comprised insertion sequence elements distributed throughout the genome, some of which cause pseudogenization. Prophage WO genes encoding some essential components of phage particle assembly are missing, while the remainder are found in five prophage regions/WO-like islands or scattered around the genome. Orthology analysis identified a core proteome of 535 orthogroups across all completed Wolbachia genomes. The majority of proteins could be annotated using Pfam and eggNOG analyses, including ankyrins and components of the Type IV secretion system. KEGG analysis revealed the absence of five genes in wAlbB which are present in other Wolbachia. The availability of a complete circular chromosome from wAlbB will enable further biochemical, molecular, and genetic analyses on this strain and related Wolbachia.

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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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