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Bibliography on: Symbiosis

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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 25 Sep 2020 at 01:51 Created: 

Symbiosis

Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2020-09-24

Desai D, Khanna A, P Pethe (2020)

PRC1 catalytic unit RING1B regulates early neural differentiation of human pluripotent stem cells.

Experimental cell research pii:S0014-4827(20)30543-7 [Epub ahead of print].

BACKGROUND: Polycomb group (PcG) proteins are histone modifiers which control gene expression by assembling into large repressive complexes termed - Polycomb repressive complex (PRC); RING1B, core catalytic subunit of PRC1 that performs H2AK119 monoubiquitination leading to gene repression. The role of PRC1 complex during early neural specification in humans is unclear; we have tried to uncover the role of PRC1 in neuronal differentiation using human pluripotent stem cells as an in vitro model.

RESULTS: We differentiated both human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) towards neural progenitor stage evident from the expression of NESTIN, TUJ1, NCAD, and PAX6. When we checked the total expression of RING1B and BMI1, we saw that they were significantly upregulated in differentiated neural progenitors compared to undifferentiated cells. Further, we used Chromatin Immunoprecipitation coupled with qPCR to determine the localization of RING1B, and the repressive histone modification H2AK119ub1 at the promoters of neuronal specific genes. We observed that RING1B localized to and catalyzed H2AK119ub1 modification at promoters of TUJ1, NCAM, and NESTIN during early differentiation and later RING1B was lost from its promoter leading their expression; while functional RING1B persisted significantly on mature neuronal genes such as IRX3, GSX2, SOX1, NEUROD1 and FOXG1 in neural progenitors.

CONCLUSION: The results of our study show that PRC1 catalytic component RING1B occupies neuronal gene promoters in human pluripotent stem cells and may prevent their precocious expression. However, when neuronal inductive signals are given, RING1B is not only removed from neuronal gene promoters, but the inhibitory H2AK119ub1 modification is also lost.

RevDate: 2020-09-24

Roche MD, Pearse IS, Bialic-Murphy L, et al (2020)

Negative effects of an allelopathic invader on AM fungal plant species drive community-level responses.

Ecology [Epub ahead of print].

The mechanisms causing invasive species impact are rarely empirically tested, limiting our ability to understand and predict subsequent changes in invaded plant communities. Invader disruption of native mutualistic interactions is a mechanism expected to have negative effects on native plant species. Specifically, disruption of native plant-fungal mutualisms may provide non-mycorrhizal plant invaders an advantage over mycorrhizal native plants. Invasive Alliaria petiolata (garlic mustard) produces secondary chemicals toxic to soil microorganisms including mycorrhizal fungi, and is known to induce physiological stress and reduce population growth rates of native forest understory plant species. Here, we report on a 10-year manipulative field experiment in replicated forest plots testing if the effects of removal of garlic mustard on the plant community support the mutualism disruption hypothesis within the entire understory herbaceous community. We compare community responses for two functional groups: the mycorrhizal vs. the non-mycorrhizal plant communities. Our results show that garlic mustard weeding alters the community composition, decreases community evenness, and increases the abundance of understory herbs that associate with mycorrhizal fungi. Conversely, garlic mustard has no significant effects on the non-mycorrhizal plant community. Consistent with the mutualism disruption hypothesis, our results demonstrate that allelochemical producing invaders modify the plant community by disproportionately impacting mycorrhizal plant species. We also demonstrate the importance of incorporating causal mechanisms of biological invasion to elucidate patterns and predict community-level responses.

RevDate: 2020-09-24

Cao Y, Jiang G, Li M, et al (2020)

Glutaredoxins play an important role in the redox homeostasis and symbiotic capacity of Azorhizobium caulinodans ORS571.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

Glutaredoxin (GRX) plays an essential role in the control of the cellular redox state and related pathways in many organisms. There is limited information on GRXs from the model nitrogen (N2)-fixing bacterium Azorhizobium caulinodans. In the present work, we identified and performed functional analyses of monothiol and dithiol GRXs in A. caulinodans in the free-living state and during symbiosis with Sesbania rostrata. Our data show that monothiol GRXs may be very important for bacterial growth under normal conditions and in response to oxidative stress due to imbalance of the redox state in grx mutants of A. caulinodans. Functional redundancies were also observed within monothiol and dithiol GRXs in terms of different physiological functions. The changes in catalase activity and iron content in grx mutants were assumed to favour the maintenance of bacterial resistance against oxidants, nodulation and N2 fixation efficiency in this bacterium. Furthermore, the monothiol GRX12 and dithiol GRX34 play a collective role in symbiotic associations between A. caulinodans and S. rostrata. Our study provided systematic evidence that further investigations are required to understand the importance of glutaredoxins in A. caulinodans and other rhizobia.

RevDate: 2020-09-24

Herrera-Rus I, Pastor JE, R Juan (2020)

Fungal colonization associated with phenological stages of a photosynthetic terrestrial temperate orchid from the Southern Iberian Peninsula.

Journal of plant research pii:10.1007/s10265-020-01225-9 [Epub ahead of print].

Fungal endophytes, both mycorrhizal and non-mycorrhizal, are involved in the development of the life cycle of orchids, providing potential beneficial relationships. Here, we assess the succession of changes in the diversity of fungal symbionts associated with a terrestrial temperate orchid species, Anacamptis morio subsp. champagneuxii, over three phenological stages: developed leaves but no stem elongation, flowering, and fruiting. Fungi endophyte associated with roots were obtained by culture in sterile conditions. A total of 18 morphotypes-one Mortierellomycota, two Basidiomycota and 15 Ascomycota-were differentiated, and were also characterized using PCR and DNA sequencing techniques. Only three of the 18 OTUs are shared among the three phenological stages examined: Westerdykella sp., a member of Ceratobasidiaceae, and Fusarium oxysporum, representing a relative abundance of between 28% (fruiting) to 41% (flowering). Our research confirmed that fungal symbionts varied among the different phenological stages examined, the peak of endophyte diversity appearing in the flowering stage. The availability of a diverse mycobiota seems to be important for the survival of orchid plants because it may cover particular physiological needs, and knowledge concerning this mycobiota is of special relevance in the establishment of reliable conservation programmes.

RevDate: 2020-09-24

Nelson C, Giraldo-Silva A, F Garcia-Pichel (2020)

A symbiotic nutrient exchange within the cyanosphere microbiome of the biocrust cyanobacterium, Microcoleus vaginatus.

The ISME journal pii:10.1038/s41396-020-00781-1 [Epub ahead of print].

Microcoleus vaginatus plays a prominent role as both primary producer and pioneer in biocrust communities from dryland soils. And yet, it cannot fix dinitrogen, essential in often nitrogen-limited drylands. But a diazotroph-rich "cyanosphere" has been described in M. vaginatus, hinting that there exists a C for N exchange between the photoautotroph and heterotrophic diazotrophs. We provide evidence for this by establishing such a symbiosis in culture and by showing that it is selective and dependent on nitrogen availability. In natural populations, provision of nitrogen resulted in loss of diazotrophs from the cyanosphere of M. vaginatus compared to controls, but provision of phosphorus did not. Co-culturing of pedigreed cyanosphere diazotroph isolates with axenic M. vaginatus resulted in copious growth in C and N-free medium, but co-culture with non-cyanosphere diazotrophs or other heterotrophs did not. Unexpectedly, bundle formation in M. vaginatus, diacritical to the genus but not seen in axenic culture, was restored in vitro by imposed nitrogen limitation or, even more strongly, by co-culture with diazotrophic partners, implicating this trait in the symbiosis. Our findings provide direct evidence for a symbiotic relationship between M. vaginatus and its cyanosphere and help explain how it can be a global pioneer in spite of its genetic shortcomings.

RevDate: 2020-09-24
CmpDate: 2020-09-24

Cerf-Bensussan N (2019)

Microbiology and immunology: An ideal partnership for a tango at the gut surface-A tribute to Philippe Sansonetti.

Cellular microbiology, 21(11):e13097.

Over the past 20 years, the highly dynamic interactions that take place between hosts and the gut microbiota have emerged as a major determinant in health and disease. The complexity of the gut microbiota represents, however, a considerable challenge, and reductionist approaches are indispensable to define the contribution of individual bacteria to host responses and to dissect molecular mechanisms. In this tribute to Philippe Sansonetti, I would like to show how rewarding collaborations with microbiologists have guided our team of immunologists in the study of host-microbiota interactions and, thanks to the use of controlled colonisation experiments in gnotobiotic mice, toward the demonstration that segmented filamentous bacteria (SFB) are indispensable to drive the post-natal maturation of the gut immune barrier in mice. The work led with Philippe Sansonetti to set up in vitro culture conditions has been one important milestone that laid the ground for in-depth characterization of the molecular attributes of this unusual symbiont. Recent suggestions that SFB may be present in the human microbiota encourage further cross-fertilising interactions between microbiologists and immunologists to define whether results from mice can be translated to humans and, if so, how SFB may be used to promote human intestinal defences against enteropathogens. Nurturing the competences to pursue this inspiring project is one legacy of Philippe Sansonetti.

RevDate: 2020-09-23

Ho-Plágaro T, Jl Morcillo R, Tamayo-Navarrete MI, et al (2020)

DLK2 regulates arbuscule hyphal branching during arbuscular mycorrhizal symbiosis.

The New phytologist [Epub ahead of print].

D14 and KAI2 receptors enable plants to distinguish between strigolactones (SLs) and karrikins (KARs), respectively, in order to trigger appropriate environmental and developmental responses. Both receptors are related to the regulation of Arbuscular Mycorrhizal (AM) formation and are members of the RsbQ-like family of α,β-hydrolases. DLK2 proteins, whose function remains unknown, constitute a third clade from the RsbQ-like protein family. We investigated whether the tomato SlDLK2 is a new regulatory component in the AM symbiosis. Genetic approaches were conducted to analyse SlDLK2 expression and to understand SlDLK2 function in AM symbiosis. We show that SlDLK2 expression in roots is AM-dependent and is associated with cells containing arbuscules. SlDLK2 ectopic expression arrests arbuscule branching and downregulates AM-responsive genes, even in the absence of symbiosis; while the opposite effect was observed upon SlDLK2 silencing. Moreover, SlDLK2 overexpression in Medicago truncatula roots showed the same altered phenotype observed in tomato roots. Interestingly, SlDLK2 interacts with DELLA, a protein that regulates arbuscule formation/degradation in AM roots. We propose that SlDLK2 is a new component of the complex plant-mediated mechanism regulating the life cycle of arbuscules in AM symbiosis.

RevDate: 2020-09-23

Shukla U, Chavali S, Mukta P, et al (2020)

Initial Experience of Critically Ill Patients with COVID-19 in Western India: A Case Series.

Indian journal of critical care medicine : peer-reviewed, official publication of Indian Society of Critical Care Medicine, 24(7):509-513.

Background: The novel coronavirus, named SARS-CoV-2, was first described in December 2019 as a cluster of pneumonia cases in Wuhan, China. It has since been declared a pandemic, with substantial mortality.

Materials and methods: In our case series, we describe the clinical presentation, characteristics, and outcomes of our initial experience of managing 24 critically ill COVID-19 patients at a designated COVID-19 ICU in Western India.

Results: Median age of the patients was 54 years, and 58% were males. All patients presented with moderate to severe acute respiratory distress syndrome (ARDS); however, only 37.5% failed trials of awake proning and required mechanical ventilation. Patients who received mechanical ventilation typically matched the H-phenotype of COVID-19 pneumonia, and 55.5% of these patients were successfully extubated.

Conclusion: The most common reason for ICU admission in our series of 24 patients with severe COVID-19 was hypoxemic respiratory failure, which responded well to conservative measures such as awake proning and oxygen supplementation. Mortality in our case series was 16.7%.

How to cite this article: Shukla U, Chavali S, Mukta P, Mapari A, Vyas A. Initial Experience of Critically Ill Patients with COVID-19 in Western India: A Case Series. Indian J Crit Care Med 2020;24(7):509-513.

RevDate: 2020-09-23

Salcedo-Porras N, Umaña-Diaz C, Bitencourt ROB, et al (2020)

The Role of Bacterial Symbionts in Triatomines: An Evolutionary Perspective.

Microorganisms, 8(9): pii:microorganisms8091438.

Insects have established mutualistic symbiotic interactions with microorganisms that are beneficial to both host and symbiont. Many insects have exploited these symbioses to diversify and expand their ecological ranges. In the Hemiptera (i.e., aphids, cicadas, and true bugs), symbioses have established and evolved with obligatory essential microorganisms (primary symbionts) and with facultative beneficial symbionts (secondary symbionts). Primary symbionts are usually intracellular microorganisms found in insects with specialized diets such as obligate hematophagy or phytophagy. Most Heteroptera (true bugs), however, have gastrointestinal (GI) tract extracellular symbionts with functions analogous to primary endosymbionts. The triatomines, are vectors of the human parasite, Trypanosoma cruzi. A description of their small GI tract microbiota richness was based on a few culturable microorganisms first described almost a century ago. A growing literature describes more complex interactions between triatomines and bacteria with properties characteristic of both primary and secondary symbionts. In this review, we provide an evolutionary perspective of beneficial symbioses in the Hemiptera, illustrating the context that may drive the evolution of symbioses in triatomines. We highlight the diversity of the triatomine microbiota, bacterial taxa with potential to be beneficial symbionts, the unique characteristics of triatomine-bacteria symbioses, and the interactions among trypanosomes, microbiota, and triatomines.

RevDate: 2020-09-23

Wilker J, Humphries S, Rosas-Sotomayor JC, et al (2020)

Genetic Diversity, Nitrogen Fixation, and Water Use Efficiency in a Panel of Honduran Common Bean (Phaseolus vulgaris L.) Landraces and Modern Genotypes.

Plants (Basel, Switzerland), 9(9): pii:plants9091238.

Common bean (Phaseolus vulgaris L.) provides critical nutrition and a livelihood for millions of smallholder farmers worldwide. Beans engage in symbiotic nitrogen fixation (SNF) with Rhizobia. Honduran hillside farmers farm marginal land and utilize few production inputs; therefore, bean varieties with high SNF capacity and environmental resiliency would be of benefit to them. We explored the diversity for SNF, agronomic traits, and water use efficiency (WUE) among 70 Honduran landrace, participatory bred (PPB), and conventionally bred bean varieties (HON panel) and 6 North American check varieties in 3 low-N field trials in Ontario, Canada and Honduras. Genetic diversity was measured with a 6K single nucleotide polymorphism (SNP) array, and phenotyping for agronomic, SNF, and WUE traits was carried out. STRUCTURE analysis revealed two subpopulations with admixture between the subpopulations. Nucleotide diversity was greater in the landraces than the PPB varieties across the genome, and multiple genomic regions were identified where population genetic differentiation between the landraces and PPB varieties was evident. Significant differences were found between varieties and breeding categories for agronomic traits, SNF, and WUE. Landraces had above average SNF capacity, conventional varieties showed higher yields, and PPB varieties performed well for WUE. Varieties with the best SNF capacity could be used in further participatory breeding efforts.

RevDate: 2020-09-23
CmpDate: 2020-09-23

Russell SL, Pepper-Tunick E, Svedberg J, et al (2020)

Horizontal transmission and recombination maintain forever young bacterial symbiont genomes.

PLoS genetics, 16(8):e1008935.

Bacterial symbionts bring a wealth of functions to the associations they participate in, but by doing so, they endanger the genes and genomes underlying these abilities. When bacterial symbionts become obligately associated with their hosts, their genomes are thought to decay towards an organelle-like fate due to decreased homologous recombination and inefficient selection. However, numerous associations exist that counter these expectations, especially in marine environments, possibly due to ongoing horizontal gene flow. Despite extensive theoretical treatment, no empirical study thus far has connected these underlying population genetic processes with long-term evolutionary outcomes. By sampling marine chemosynthetic bacterial-bivalve endosymbioses that range from primarily vertical to strictly horizontal transmission, we tested this canonical theory. We found that transmission mode strongly predicts homologous recombination rates, and that exceedingly low recombination rates are associated with moderate genome degradation in the marine symbionts with nearly strict vertical transmission. Nonetheless, even the most degraded marine endosymbiont genomes are occasionally horizontally transmitted and are much larger than their terrestrial insect symbiont counterparts. Therefore, horizontal transmission and recombination enable efficient natural selection to maintain intermediate symbiont genome sizes and substantial functional genetic variation.

RevDate: 2020-09-23
CmpDate: 2020-09-23

Yamamoto T, Hasegawa H, Nakase Y, et al (2020)

Cryptic Diversity in the Aphid-Parasitizing Wasp Protaphidius nawaii (Hymenoptera: Braconidae): Discovery of Two Attendant-Ant-Specific mtDNA Lineages.

Zoological science, 37(2):117-121.

The parasitoid wasp Protaphidius nawaii parasitizes the aphid Stomaphis japonica, which is obligatorily attended by several species of ants of genus Lasius. Subgenus Lasius or Dendrolasius ants use different defense strategies to protect the aphids that they attend (Lasius, shelter building; Dendrolasius, aggressive attack). We performed molecular phylogenetic analysis based on partial mitochondrial DNA sequences of P. nawaii and found that the parasitoid wasp consists of two highly differentiated genetic lineages. Although these two lineages distributed sympatrically, one tends to parasitize aphids attended by ants of subgenus Lasius, and the other parasitizes aphids attended by ants of subgenus Dendrolasius. The two lineages of P. nawaii appear to exhibit different oviposition behaviors adapted to the different aphid-protection strategies of the two ant subgenera.

RevDate: 2020-09-23
CmpDate: 2020-09-23

Sow A, Brévault T, Benoit L, et al (2019)

Deciphering host-parasitoid interactions and parasitism rates of crop pests using DNA metabarcoding.

Scientific reports, 9(1):3646.

An accurate estimation of parasitism rates and diversity of parasitoids of crop insect pests is a prerequisite for exploring processes leading to efficient natural biocontrol. Traditional methods such as rearing have been often limited by taxonomic identification, insect mortality and intensive work, but the advent of high-throughput sequencing (HTS) techniques, such as DNA metabarcoding, is increasingly seen as a reliable and powerful alternative approach. Little has been done to explore the benefits of such an approach for estimating parasitism rates and parasitoid diversity in an agricultural context. In this study, we compared the composition of parasitoid species and parasitism rates between rearing and DNA metabarcoding of host eggs and larvae of the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera, Noctuidae), collected from millet fields in Senegal. We first assessed the detection threshold for the main ten endoparasitoids, by sequencing PCR products obtained from artificial dilution gradients of the parasitoid DNAs in the host moth. We then assessed the potential of DNA metabarcoding for diagnosing parasitism rates in samples collected from the field. Under controlled conditions, our results showed that relatively small quantities of parasitoid DNA (0.07 ng) were successfully detected within an eight-fold larger quantity of host DNA. Parasitoid diversity and parasitism rate estimates were always higher for DNA metabarcoding than for host rearing. Furthermore, metabarcoding detected multi-parasitism, cryptic parasitoid species and differences in parasitism rates between two different sampling sites. Metabarcoding shows promise for gaining a clearer understanding of the importance and complexity of host-parasitoid interactions in agro-ecosystems, with a view to improving pest biocontrol strategies.

RevDate: 2020-09-23
CmpDate: 2020-09-23

Corriero G, Pierri C, Mercurio M, et al (2019)

A Mediterranean mesophotic coral reef built by non-symbiotic scleractinians.

Scientific reports, 9(1):3601.

This is the first description of a Mediterranean mesophotic coral reef. The bioconstruction extended for 2.5 km along the Italian Adriatic coast in the bathymetric range -30/-55 m. It appeared as a framework of coral blocks mostly built by two scleractinians, Phyllangia americana mouchezii (Lacaze-Duthiers, 1897) and Polycyathus muellerae (Abel, 1959), which were able to edify a secondary substrate with high structural complexity. Scleractinian corallites were cemented by calcified polychaete tubes and organized into an interlocking meshwork that provided the reef stiffness. Aggregates of several individuals of the bivalve Neopycnodonte cochlear (Poli, 1795) contributed to the compactness of the structure. The species composition of the benthic community showed a marked similarity with those described for Mediterranean coralligenous communities and it appeared to be dominated by invertebrates, while calcareous algae, which are usually considered the main coralligenous reef-builders, were poorly represented. Overall, the studied reef can be considered a unique environment, to be included in the wide and diversified category of Mediterranean bioconstructions. The main reef-building scleractinians lacked algal symbionts, suggesting that heterotrophy had a major role in the metabolic processes that supported the production of calcium carbonate. The large amount of available suspended organic matter in the area could be the main nutritional source for these species, as already suggested in the literature referred to Mediterranean cold-water corals.

RevDate: 2020-09-22

Sun YH, Gu CX, Li GZ, et al (2020)

Arbuscular mycorrhizal fungus-mediated amelioration of NO2-induced phytotoxicity in tomato.

Ecotoxicology and environmental safety, 205:111350 pii:S0147-6513(20)31187-8 [Epub ahead of print].

Atmospheric nitrogen dioxide (NO2) negatively affects plant (crop) growth and development, as well the yield and quality in some regions or environments. Arbuscular mycorrhizal fungus (AMF)-mediated amelioration of NO2-induced plant damage has been reported, but the underlying mechanisms remained unclear. This study explored the beneficial effect of AMF symbiosis on tomato plant responses to NO2 at physiology, biochemistry, and gene expression, with an emphasis on nitrate metabolism, antioxidative defense, and photosynthetic performance. Pot-grown plants were used in the experiments, which were performed in laboratory from February to November 2019. NO2 fumigation with a dose of 10 ± 1 ppm was carried out after 50 d of plant growth, and data were collected following 8 h of fumigation. NO2 fumigation (+NO2) and AMF inoculation (+AMF), alone and especially in combination (NO2 + AMF), increased the gene expression of nitrate- and nitrite reductase, and their enzymatic activity in leaves, such as by 61%, 27%, and 126% for the activity of nitrate reductase, and by 95%, 37%, and 188% for nitrite reductase, respectively, in +NO2, +AMF, and AMF + NO2 plants relative the control (-NO2, -AMF) levels. Following NO2 exposure, +AMF leaves displayed stronger activities of superoxide dismutase, peroxidase and catalase, and higher content of glutathione and ratio of its reduced form to oxidized form, as compared with -AMF ones. Correspondingly, lesser oxidative damage was detected in +AMF than in -AMF plants, as indicated by the contents of H2O2 and malondialdehyde, electrolyte leakage, also by in situ visualization for the formation of H2O2, superoxide anion, and dead cells. The increased antioxidative capacity in +AMF plants was correlated with enhanced expression of antioxidation-related genes. Exposure to NO2 substantially impaired photosynthetic processes in both + AMF and -AMF plants, but an obvious mitigation was observed in the former than in the latter. For example, the total chlorophyll, net photosynthetic rate, stomatal conductance, and ribulose-1,5-bisphosphate carboxylase activity were 18%, 27%, 26%, and 40% higher, respectively, in +AMF than in -AMF plants under NO2 stress. The differential photosynthetic performance was also revealed by chlorophyll fluorescence imaging. We analyzed the expression patterns of some genes related to photosynthesis and carbon metabolisms, and found that all of them exclusively presented a higher expression level in +AMF plants relative to -AMF ones under NO2 stress. Taken together, this study provided evidence that AMF symbiosis played a positively regulatory role in host plant responses to NO2, probably by increasing leaf nitrate metabolism and antioxidative defense, and maintaining the photosynthetic efficiency to some extent, wherein the transcription regulation might be a main target.

RevDate: 2020-09-22

Pendse S, Kale V, A Vaidya (2020)

Extracellular Vesicles Isolated from Mesenchymal Stromal Cells Primed with Hypoxia: Novel strategy in Regenerative Medicine.

Current stem cell research & therapy pii:CSCR-EPUB-110061 [Epub ahead of print].

Mesenchymal stromal cells (MSCs) regulate other cell types through a strong paracrine component called the secretome, comprising of several bioactive entities. The composition of the MSCs' secretome is dependent upon the microenvironment in which they thrive, and hence, it could be altered by pre-conditioning the MSCs during in vitro culture. The primary aim of this review is to discuss various strategies that are being used for pre-conditioning of MSCs, also known as "priming of MSCs", in the context of improving their therapeutic potential. Several studies have underscored the importance of extracellular vesicles (EVs) derived from primed MSCs in improving their efficacy in the treatment of various diseases. We have previously shown that co-culturing hematopoietic stem cells (HSCs) with hypoxiaprimed MSCs improves their engraftment potential. Now the question we pose is would priming of MSCs with hypoxiafavorably alter theirsecretome and would this altered secretome work as effectively as the cell to cell contact did? Here we review the current strategies of using the secretome, specifically the EVs (microvesicles and exosomes), collected from the primed MSCs with the intention of expanding HSCs ex vivo. We speculate that an effective priming of MSCs in vitrocould modulate the molecular profile of their secretome, which could eventually be used as a cell-free biologic in clinical settings.

RevDate: 2020-09-22
CmpDate: 2020-09-22

Li J, Lemer S, Kirkendale L, et al (2020)

Shedding light: a phylotranscriptomic perspective illuminates the origin of photosymbiosis in marine bivalves.

BMC evolutionary biology, 20(1):50.

BACKGROUND: Photosymbiotic associations between metazoan hosts and photosynthetic dinoflagellates are crucial to the trophic and structural integrity of many marine ecosystems, including coral reefs. Although extensive efforts have been devoted to study the short-term ecological interactions between coral hosts and their symbionts, long-term evolutionary dynamics of photosymbiosis in many marine animals are not well understood. Within Bivalvia, the second largest class of mollusks, obligate photosymbiosis is found in two marine lineages: the giant clams (subfamily Tridacninae) and the heart cockles (subfamily Fraginae), both in the family Cardiidae. Morphologically, giant clams show relatively conservative shell forms whereas photosymbiotic fragines exhibit a diverse suite of anatomical adaptations including flattened shells, leafy mantle extensions, and lens-like microstructural structures. To date, the phylogenetic relationships between these two subfamilies remain poorly resolved, and it is unclear whether photosymbiosis in cardiids originated once or twice.

RESULTS: In this study, we establish a backbone phylogeny for Cardiidae utilizing RNASeq-based transcriptomic data from Tridacninae, Fraginae and other cardiids. A variety of phylogenomic approaches were used to infer the relationship between the two groups. Our analyses found conflicting gene signals and potential rapid divergence among the lineages. Overall, results support a sister group relationship between Tridacninae and Fraginae, which diverged during the Cretaceous. Although a sister group relationship is recovered, ancestral state reconstruction using maximum likelihood-based methods reveals two independent origins of photosymbiosis, one at the base of Tridacninae and the other within a symbiotic Fraginae clade.

CONCLUSIONS: The newly revealed common ancestry between Tridacninae and Fraginae brings a possibility that certain genetic, metabolic, and/or anatomical exaptations existed in their last common ancestor, which promoted both lineages to independently establish photosymbiosis, possibly in response to the modern expansion of reef habitats.

RevDate: 2020-09-22
CmpDate: 2020-09-22

Ye C, Li J, Ran Y, et al (2019)

The nest fungus of the lower termite Reticulitermes labralis.

Scientific reports, 9(1):3384.

Fitness-determining interactions with fungi have often been considered a by-product of social evolution in insects. In higher termites, the mutualistic association between the basidiomycete genus Termitomyces and Macrotermitinae is well known. However, whether and how lower termites use fungi is unclear. Here, we found a large amount of brown sclerotium-forming fungi in egg piles of the lower termite Reticulitermes labralis and identified the sclerotia as Fibulorhizoctonia sp. There was a significant difference in morphology between the sclerotia and the termite eggs. The workers of R. labralis and R. chinensis actively gathered the sclerotia into the egg piles within their nests, whereas the workers of R. aculabialis did not gather sclerotia outside their nests. None of the sclerotia in the egg piles germinated in the presence of workers. However, the sclerotia germinated in the absence of workers, and then the hyphae killed the termite eggs. The data from cellulase activity demonstrated that Fibulorhizoctonia sp. was able to exhaustively digest cellulose into glucose.We confirmed for the first time that the workers carrying the sclerotia into the piles of eggs is not due to mistaking the sclerotia for their eggs and that the workers of R. labralis may be able to select favourite fungi.

RevDate: 2020-09-22
CmpDate: 2020-09-22

Magel JMT, Burns JHR, Gates RD, et al (2019)

Effects of bleaching-associated mass coral mortality on reef structural complexity across a gradient of local disturbance.

Scientific reports, 9(1):2512.

Structural complexity underpins the ecological functioning of coral reefs. However, rising ocean temperatures and associated coral bleaching threaten the structural integrity of these important ecosystems. Despite the increased frequency of coral bleaching events, few studies to date have examined changes in three-dimensional (3D) reef structural complexity following severe bleaching. The influence of local stressors on reef complexity also remains poorly understood. In the wake of the 2015-2016 El Niño-induced mass coral bleaching event, we quantified the effects of severe heat stress on 3D reef structural complexity across a gradient of local human disturbance. Using Structure-from-Motion photogrammetry we created 3D reconstructions of permanent reef plots and observed substantial declines in reef structural complexity, measured as surface rugosity and terrain ruggedness, and a detectable loss of habitat volume one year after the bleaching event. 3D reef complexity also declined with increasing levels of human disturbance, and with decreasing densities of branching and massive corals. These findings improve our understanding of the effects of local and global stressors on the structural foundation of coral reef ecosystems. In the face of accelerating climate change, mitigating local stressors may increase reef structural complexity, thereby heightening reef resilience to future bleaching events.

RevDate: 2020-09-22
CmpDate: 2020-09-22

Vujanovic V, Kim SH, Lahlali R, et al (2019)

Spectroscopy and SEM imaging reveal endosymbiont-dependent components changes in germinating kernel through direct and indirect coleorhiza-fungus interactions under stress.

Scientific reports, 9(1):1665.

In the present study, FTIR spectroscopy and hyperspectral imaging was introduced as a non-destructive, sensitive-reliable tool for assessing the tripartite kernel-fungal endophyte environment interaction. Composition of coleorhizae of Triticum durum was studied under ambient and drought stress conditions. The OH-stretch IR absorption spectrum suggests that the water-deficit was possibly improved or moderated by kernel's endophytic partner. The OH-stretch frequency pattern coincides with other (growth and stress) related molecular changes. Analysis of lipid (3100-2800 cm-1) and protein (1700-1550 cm-1) regions seems to demonstrate that drought has a positive impact on lipids. The fungal endosymbiont direct contact with kernel during germination had highest effect on both lipid and protein (Amide I and II) groups, indicating an increased stress resistance in inoculated kernel. Compared to the indirect kernel-fungus interaction and to non-treated kernels (control), direct interaction produced highest effect on lipids. Among treatments, the fingerprint region (1800-800 cm-1) and SEM images indicated an important shift in glucose oligosaccharides, possibly linked to coleorhiza-polymer layer disappearance. Acquired differentiation in coleorhiza composition of T. durum, between ambient and drought conditions, suggests that FTIR spectroscopy could be a promising tool for studying endosymbiont-plant interactions within a changing environment.

RevDate: 2020-09-21

Lin YE, Wang HL, Lu KH, et al (2020)

Water extract of Armillaria mellea (Vahl) P. Kumm. alleviates the depression-like behaviors in acute- and chronic mild stress-induced rodent models via anti-inflammatory action.

Journal of ethnopharmacology pii:S0378-8741(20)33280-3 [Epub ahead of print].

ETHNOPHARMACOLOGY RELEVANCE: Armillaria mellea (Vahl) P. Kumm. (AM) is an edible mushroom that has been reported as treatment for several neurological disorders, such as dizziness and epilepsy in Asia. Importantly, AM shares a symbiotic relationship with Gastrodia elata Blume (GE), a medicinal herb with antidepressant-like properties. Researchers believe that AM may possess pharmacological properties similar to GE due to their symbiosis, however, few studies have investigated the pharmacological effect of AM.

AIM OF THE STUDY: The aim of this study was to explore the potential of AM as an antidepressant in forced-swimming test (FST) and unpredictable chronic mild stress (UCMS) rodent models and investigate its possible underlying mechanism.

MATERIALS AND METHODS: Rats were orally administrated with 250, 500, and 1000 mg/kg body weight (bw) water extract of AM (WAM) for 28 and 35 consecutive days prior to the FST and UCMS protocols, respectively. The cerebral serotonin (5-HT) and the metabolites in the frontal cortex of rats were measured. The brain was dissected and the blood was collected to investigate the levels of inflammatory-related signaling pathway.

RESULTS: All doses of WAM reduced the immobility time in the FST without disturbing autonomic locomotion. All doses of WAM prevented stress-induced abnormal behaviors in the UCMS model, including decreased sucrose preference and hypoactivity. 500 and 1000 mg/kg bw WAM attenuated the stress-induced increases in IL-1β and TNF-α in the serum and cerebrum. 1000 mg/kg bw WAM alleviated brain inflammation by reducing the protein expression of ionized calcium binding adaptor molecule 1.

CONCLUSION: WAM exhibited acute and chronic antidepressant-like effects, and may result from the anti-inflammatory actions. Therefore, the development of AM as a dietary therapy or adjuvant for depression treatment should be considered.

RevDate: 2020-09-21

Ip JC, Xu T, Sun J, et al (2020)

Host-Endosymbiont Genome Integration in a Deep-Sea Chemosymbiotic Clam.

Molecular biology and evolution pii:5909661 [Epub ahead of print].

Endosymbiosis with chemosynthetic bacteria has enabled many deep-sea invertebrates to thrive at hydrothermal vents and cold seeps, but most previous studies on this mutualism have focused on the bacteria only. Vesicomyid clams dominate global deep-sea chemosynthesis-based ecosystems. They differ from most deep-sea symbiotic animals in passing their symbionts from parent to offspring, enabling intricate co-evolution between the host and the symbiont. Here, we sequenced the genomes of the clam Archivesica marissinica (Bivalvia: Vesicomyidae) and its bacterial symbiont to understand the genomic/metabolic integration behind this symbiosis. At 1.52 gigabases, the clam genome encodes 28 genes horizontally transferred from bacteria, a large number of pseudogenes and transposable elements whose massive expansion corresponded to the timing of the rise and subsequent divergence of symbiont-bearing vesicomyids. The genome exhibits gene family expansion in cellular processes that likely facilitate chemoautotrophy, including gas delivery to support energy and carbon production, metabolite exchange with the symbiont, and regulation of the bacteriocyte population. Contraction in cellulase genes is likely adaptive to the shift from phytoplankton-derived to bacteria-based food. It also shows contraction in bacterial recognition gene familie, indicative of suppressed immune response to the endosymbiont. The gammaproteobacterium endosymbiont has a reduced genome of 1.03 megabases but retains complete pathways for sulfur oxidation, carbon fixation, and biosynthesis of 20 common amino acids, indicating the host's high dependence on the symbiont for nutrition. Overall, the host-symbiont genomes show not only tight metabolic complementarity, but also distinct signatures of co-evolution allowing the vesicomyids to thrive in chemosynthesis-based ecosystems.

RevDate: 2020-09-21

Spahr E, Kasson MT, T Kijimoto (2020)

Micro-computed tomography permits enhanced visualization of mycangia across development and between sexes in Euwallacea ambrosia beetles.

PloS one, 15(9):e0236653 pii:PONE-D-20-02806.

Symbiosis can facilitate the development of specialized organs in the host body to maintain relationships with beneficial microorganisms. To understand the developmental and genetic mechanisms by which such organs develop, it is critical to first investigate the morphology and developmental timing of these structures during the onset of host development. We utilized micro-computed tomography (μCT) to describe the morphology and development of mycangia, a specialized organ, in the Asian ambrosia beetle species Euwallacea validus which maintains a mutualistic relationship with the Ascomycete fungus, Fusarium oligoseptatum. We scanned animals in larval, pupal and adult life stages and identified that mycangia develop during the late pupal stage. Here we reconcile preliminary evidence and provide additional morphological data for a second paired set of structures, including the superior, medial mycangia and an inferior, lateral pair of pouch-like structures, in both late-stage pupae and adult female beetles. Furthermore, we report the possible development of rudimentary, or partially developed pairs of medial mycangia in adult male beetles which has never been reported for any male Xyleborini. Our results illustrate the validity of μCT in observing soft tissues and the complex nature of mycangia morphology and development.

RevDate: 2020-09-21

Kang Z, Zou J, Huang Y, et al (2020)

Tuber melanosporum shapes nirS-type denitrifying and ammonia-oxidizing bacterial communities in Carya illinoinensis ectomycorrhizosphere soils.

PeerJ, 8:e9457 pii:9457.

Background: NirS-type denitrifying bacteria and ammonia-oxidizing bacteria (AOB) play a key role in the soil nitrogen cycle, which may affect the growth and development of underground truffles. We aimed to investigate nirS-type denitrifying bacterial and AOB community structures in the rhizosphere soils of Carya illinoinensis seedlings inoculated with the black truffle (Tuber melanosporum) during the early symbiotic stage.

Methods: The C. illinoinensis seedlings inoculated with or without T. melanosporum were cultivated in a greenhouse for six months. Next-generation sequencing (NGS) technology was used to analyze nirS-type denitrifying bacterial and AOB community structures in the rhizosphere soils of these seedlings. Additionally, the soil properties were determined.

Results: The results indicated that the abundance and diversity of AOB were significantly reduced due to the inoculation of T. melanosporum, while these of nirS-type denitrifying bacteria increased significantly. Proteobacteria were the dominant bacterial groups, and Rhodanobacter, Pseudomonas, Nitrosospira and Nitrosomonas were the dominant classified bacterial genera in all the soil samples. Pseudomonas was the most abundant classified nirS-type denitrifying bacterial genus in ectomycorrhizosphere soils whose relative abundance could significantly increase after T. melanosporum inoculation. A large number of unclassified nirS-type denitrifying bacteria and AOB were observed. Moreover, T. melanosporum inoculation had little effect on the pH, total nitrogen (TN), nitrate-nitrogen (NO 3 - -N) and ammonium-nitrogen (NH 4 + -N) contents in ectomycorrhizosphere soils. Overall, our results showed that nirS-type denitrifying bacterial and AOB communities in C. illinoinensis rhizosphere soils were significantly affected by T. melanosporum on the initial stage of ectomycorrhizal symbiosis, without obvious variation of soil N contents.

RevDate: 2020-09-21

Griffin LH, LK Reed (2020)

Effect of gut microbiota on α-amanitin tolerance in Drosophila tripunctata.

Ecology and evolution, 10(17):9419-9427 pii:ECE36630.

The bacterial gut microbiota of many animals is known to be important for many physiological functions including detoxification. The selective pressures imposed on insects by exposure to toxins may also be selective pressures on their symbiotic bacteria, who thus may contribute to the mechanism of toxin tolerance for the insect. Amatoxins are a class of cyclopeptide mushroom toxins that primarily act by binding to RNA polymerase II and inhibiting transcription. Several species of mycophagous Drosophila are tolerant to amatoxins found in mushrooms of the genus Amanita, despite these toxins being lethal to most other known eukaryotes. These species can tolerate amatoxins in natural concentrations to utilize toxic mushrooms as larval hosts, but the mechanism by which these species are tolerant remains unknown. Previous data have shown that a local population of D. tripunctata exhibits significant genetic variation in toxin tolerance. This study assesses the potential role of the microbiome in α-amanitin tolerance in six wild-derived strains of Drosophila tripunctata. Normal and antibiotic-treated samples of six strains were reared on diets with and without α-amanitin, and then scored for survival from the larval stage to adulthood and for development time to pupation. Our results show that a substantial reduction in bacterial load does not influence toxin tolerance in this system, while confirming genotype and toxin-specific effects on survival are independent of the microbiome composition. Thus, we conclude that this adaptation to exploit toxic mushrooms as a host is likely intrinsic to the fly's genome and not a property of their microbiome.

RevDate: 2020-09-21
CmpDate: 2020-09-21

Rafiqi AM, Rajakumar A, E Abouheif (2020)

Origin and elaboration of a major evolutionary transition in individuality.

Nature, 585(7824):239-244.

Obligate endosymbiosis, in which distantly related species integrate to form a single replicating individual, represents a major evolutionary transition in individuality1-3. Although such transitions are thought to increase biological complexity1,2,4-6, the evolutionary and developmental steps that lead to integration remain poorly understood. Here we show that obligate endosymbiosis between the bacteria Blochmannia and the hyperdiverse ant tribe Camponotini7-11 originated and also elaborated through radical alterations in embryonic development, as compared to other insects. The Hox genes Abdominal A (abdA) and Ultrabithorax (Ubx)-which, in arthropods, normally function to differentiate abdominal and thoracic segments after they form-were rewired to also regulate germline genes early in development. Consequently, the mRNAs and proteins of these Hox genes are expressed maternally and colocalize at a subcellular level with those of germline genes in the germplasm and three novel locations in the freshly laid egg. Blochmannia bacteria then selectively regulate these mRNAs and proteins to make each of these four locations functionally distinct, creating a system of coordinates in the embryo in which each location performs a different function to integrate Blochmannia into the Camponotini. Finally, we show that the capacity to localize mRNAs and proteins to new locations in the embryo evolved before obligate endosymbiosis and was subsequently co-opted by Blochmannia and Camponotini. This pre-existing molecular capacity converged with a pre-existing ecological mutualism12,13 to facilitate both the horizontal transfer10 and developmental integration of Blochmannia into Camponotini. Therefore, the convergence of pre-existing molecular capacities and ecological interactions-as well as the rewiring of highly conserved gene networks-may be a general feature that facilitates the origin and elaboration of major transitions in individuality.

RevDate: 2020-09-21
CmpDate: 2020-09-21

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

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

PLoS neglected tropical diseases, 14(8):e0008615.

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

RevDate: 2020-09-21
CmpDate: 2020-09-21

Dombrowski N, Williams TA, Sun J, et al (2020)

Undinarchaeota illuminate DPANN phylogeny and the impact of gene transfer on archaeal evolution.

Nature communications, 11(1):3939.

The recently discovered DPANN archaea are a potentially deep-branching, monophyletic radiation of organisms with small cells and genomes. However, the monophyly and early emergence of the various DPANN clades and their role in life's evolution are debated. Here, we reconstructed and analysed genomes of an uncharacterized archaeal phylum (Candidatus Undinarchaeota), revealing that its members have small genomes and, while potentially being able to conserve energy through fermentation, likely depend on partner organisms for the acquisition of certain metabolites. Our phylogenomic analyses robustly place Undinarchaeota as an independent lineage between two highly supported 'DPANN' clans. Further, our analyses suggest that DPANN have exchanged core genes with their hosts, adding to the difficulty of placing DPANN in the tree of life. This pattern can be sufficiently dominant to allow identifying known symbiont-host clades based on routes of gene transfer. Together, our work provides insights into the origins and evolution of DPANN and their hosts.

RevDate: 2020-09-21
CmpDate: 2020-09-21

Hurabielle C, Link VM, Bouladoux N, et al (2020)

Immunity to commensal skin fungi promotes psoriasiform skin inflammation.

Proceedings of the National Academy of Sciences of the United States of America, 117(28):16465-16474.

Under steady-state conditions, the immune system is poised to sense and respond to the microbiota. As such, immunity to the microbiota, including T cell responses, is expected to precede any inflammatory trigger. How this pool of preformed microbiota-specific T cells contributes to tissue pathologies remains unclear. Here, using an experimental model of psoriasis, we show that recall responses to commensal skin fungi can significantly aggravate tissue inflammation. Enhanced pathology caused by fungi preexposure depends on Th17 responses and neutrophil extracellular traps and recapitulates features of the transcriptional landscape of human lesional psoriatic skin. Together, our results propose that recall responses directed to skin fungi can directly promote skin inflammation and that exploration of tissue inflammation should be assessed in the context of recall responses to the microbiota.

RevDate: 2020-09-21
CmpDate: 2020-09-21

González-Escobar JL, Pereyra-Camacho MA, De Léon-Rodríguez A, et al (2020)

Biodegradation of recalcitrant compounds and phthalates by culturable bacteria isolated from Liometopum apiculatum microbiota.

World journal of microbiology & biotechnology, 36(5):73 pii:10.1007/s11274-020-02850-1.

Liometopum apiculatum is a species of ants widely distributed in arid and semi-arid ecosystems where there is a relative food shortage compared with tropical ecosystems. L. apiculatum has established an ecological balance involving symbiotic interactions, which have allowed them to survive through mechanisms that are still unknown. Therefore, the aim of this study was to explore the metabolic potential of isolated bacteria from L. apiculatum using enzymatic activity assay and substrate assimilation. Results revealed a complex bacteria consortium belonging to Proteobacteria, Firmicutes, and Actinobacteria phylum. Most of the isolated bacteria showed activities associated with biopolymers degradation, from them Exiguobacterium and B. simplex showed the highest amylolytic activity (27 U/mg protein), while A. johnsonii and B. pumulis showed the highest cellulolytic and xylanolytic activities (1 and 2.9 U/mg protein, respectively). By other hand, some microorganisms such as S. ficaria, E. asburiae, P. agglomerans, A. johnsonii, S. rubidaea, S. marcescens, S. warneri, and M. hydrocarbonoxydans were able to grow up to 1000 mg/L of phthalates esters. These results not only revealed the important contribution of the symbionts in L apiculatum ants feeding habits, but also have shown a promising source of enzymes with potential biotechnological applications such as lignocellulosic biomass hydrolysis and bioremediation processes.

RevDate: 2020-09-21
CmpDate: 2020-09-21

Hsieh S, Porter NT, Donermeyer DL, et al (2020)

Polysaccharide Capsules Equip the Human Symbiont Bacteroides thetaiotaomicron to Modulate Immune Responses to a Dominant Antigen in the Intestine.

Journal of immunology (Baltimore, Md. : 1950), 204(4):1035-1046.

Bacteria express multiple diverse capsular polysaccharides (CPSs) for protection against environmental and host factors, including the host immune system. Using a mouse TCR transgenic CD4+ T cell, BθOM, that is specific for B. thetaiotaomicron and a complete set of single CPS-expressing B. thetaiotaomicron strains, we ask whether CPSs can modify the immune responses to specific bacterial Ags. Acapsular B. thetaiotaomicron, which lacks all B. thetaiotaomicron CPSs, stimulated BθOM T cells more strongly than wild-type B. thetaiotaomicron Despite similar levels of BθOM Ag expression, many single CPS-expressing B. thetaiotaomicron strains were antistimulatory and weakly activated BθOM T cells, but a few strains were prostimulatory and strongly activated BθOM T cells just as well or better than an acapsular strain. B. thetaiotaomicron strains that expressed an antistimulatory CPS blocked Ag delivery to the immune system, which could be rescued by Fc receptor-dependent Ab opsonization. All single CPS-expressing B. thetaiotaomicron strains stimulated the innate immune system to skew toward M1 macrophages and release inflammatory cytokines in an MyD88-dependent manner, with antistimulatory CPS activating the innate immune system in a weaker manner than prostimulatory CPS. The expression of antistimulatory versus prostimulatory CPSs on outer membrane vesicles also regulated immune responses. Moreover, antistimulatory and prostimulatory single CPS-expressing B. thetaiotaomicron strains regulated the activation of Ag-specific and polyclonal T cells as well as clearance of dominant Ag in vivo. These studies establish that the immune responses to specific bacterial Ags can be modulated by a diverse set of CPSs.

RevDate: 2020-09-21
CmpDate: 2020-09-21

Petrzik K, Koloniuk I, Sehadová H, et al (2019)

Chrysoviruses Inhabited Symbiotic Fungi of Lichens.

Viruses, 11(12):.

A lichen body is formed most often from green alga cells trapped in a net of ascomycetous fungi and accompanied by endolichenic or parasitic fungi, other algae, and symbiotic or free-living bacteria. The lichen's microcosmos is inhabited by mites, insects, and other animals for which the lichen is a source of food or a place to live. Novel, four-segmented dsRNA viruses were detected in saxicolous Chrysothrixchlorina and Leprariaincana lichens. Comparison of encoded genome proteins revealed classification of the viruses to the genus Alphachrysovirus and a relationship to chrysoviruses from filamentous ascomycetous fungi. We propose the names Chrysothrix chrysovirus 1 (CcCV1) and Lepraria chrysovirus 1 (LiCV1) as acronyms for these viruses. Surprisingly, observation of Chrysothrixchlorina hybridization with fluorescent-labelled virus probe by confocal microscope revealed that the CcCV1 virus is not present in the lichen body-forming fungus but in accompanying endolichenic Penicilliumcitreosulfuratum fungus. These are the first descriptions of mycoviruses from a lichen environment.

RevDate: 2020-09-19

Cantamessa S, Massa N, Gamalero E, et al (2020)

Phytoremediation of a Highly Arsenic Polluted Site, Using Pteris vittata L. and Arbuscular Mycorrhizal Fungi.

Plants (Basel, Switzerland), 9(9): pii:plants9091211.

Phytoremediation is a promising green technique for the restoration of a polluted environment, but there is often a gap between lab and field experiments. The fern, Pteris vittata L., can tolerate a high soil arsenic concentration and rapidly accumulate the metalloid in its fronds. Arbuscular mycorrhizal fungi (AMF) are mutualistic fungi that form a symbiosis with most land plants' roots, improve their growth, and induce stress tolerance. This paper reports the results obtained using P. vittata inoculated with AMF, to extract Arsenic (As) from an industrial site highly contaminated also by other pollutants. Two experiments have been performed. In the first one, AMF colonized ferns were grown for two years under controlled conditions in soil coming from the metallurgic site. Positive effects on plant health and As phytoextraction and accumulation were detected. Then, considering these results, we performed a three year in situ experiment in the industrial site, to assess the remediation of As at two different depths. Our results show that the colonization of P. vittata with AMF improved the remediation process of As with a significant impact on the depth 0-0.2 m.

RevDate: 2020-09-19

Kin LX, Butler CA, Slakeski N, et al (2020)

Metabolic cooperativity between Porphyromonas gingivalis and Treponema denticola.

Journal of oral microbiology, 12(1):1808750.

Background: Porphyromonas gingivalis and Treponema denticola are proteolytic periodontopathogens that co-localize in polymicrobial subgingival plaque biofilms, display in vitro growth symbiosis and synergistic virulence in animal models of disease. These symbioses are underpinned by a range of metabolic interactions including cooperative hydrolysis of glycine-containing peptides to produce free glycine, which T. denticola uses as a major energy and carbon source.

Objective: To characterize the P. gingivalis gene products essential for these interactions. Methods: The P. gingivalis transcriptome exposed to cell-free T. denticola conditioned medium was determined using RNA-seq. P. gingivalis proteases potentially involved in hydrolysis of glycine-containing peptides were identified using a bioinformatics approach.

Results: One hundred and thirty-twogenes displayed differential expression, with the pattern of gene expression consistent with succinate cross-feeding from T. denticola to P. gingivalis and metabolic shifts in the P. gingivalis folate-mediated one carbon superpathway. Interestingly, no P. gingivalis proteases were significantly up-regulated. Three P. gingivalis proteases were identified as candidates and inactivated to determine their role in the release of free glycine. P. gingivalis PG0753 and PG1788 but not PG1605 are involved in the hydrolysis of glycine-containing peptides, making free glycine available for T. denticola utilization.

Conclusion: Collectively these metabolic interactions help to partition resources and engage synergistic interactions between these two species.

RevDate: 2020-09-18

Nishiyama K, Takaki T, Sugiyama M, et al (2020)

Extracellular Vesicles Produced by Bifidobacterium longum Export Mucin-Binding Proteins.

Applied and environmental microbiology, 86(19): pii:AEM.01464-20.

Extracellular proteins are important factors in host-microbe interactions; however, the specific factors that enable bifidobacterial adhesion and survival in the gastrointestinal (GI) tract are not fully characterized. Here, we discovered that Bifidobacterium longum NCC2705 cultured in bacterium-free supernatants of human fecal fermentation broth released a myriad of particles into the extracellular environment. The aim of this study was to characterize the physiological properties of these extracellular particles. The particles, approximately 50 to 80 nm in diameter, had high protein and double-stranded DNA contents, suggesting that they were extracellular vesicles (EVs). A proteomic analysis showed that the EVs primarily consisted of cytoplasmic proteins with crucial functions in essential cellular processes. We identified several mucin-binding proteins by performing a biomolecular interaction analysis of phosphoketolase, GroEL, elongation factor Tu (EF-Tu), phosphoglycerate kinase, transaldolase (Tal), and heat shock protein 20 (Hsp20). The recombinant GroEL and Tal proteins showed high binding affinities to mucin. Furthermore, the immobilization of these proteins on microbeads affected the permanence of the microbeads in the murine GI tract. These results suggest that bifidobacterial exposure conditions that mimic the intestine stimulate B. longum EV production. The resulting EVs exported several cytoplasmic proteins that may have promoted B. longum adhesion. This study improved our understanding of the Bifidobacterium colonization strategy in the intestinal microbiome.IMPORTANCEBifidobacterium is a natural inhabitant of the human gastrointestinal (GI) tract. Morphological observations revealed that extracellular appendages of bifidobacteria in complex microbial communities are important for understanding its adaptations to the GI tract environment. We identified dynamic extracellular vesicle (EV) production by Bifidobacterium longum in bacterium-free fecal fermentation broth that was strongly suggestive of differing bifidobacterial extracellular appendages in the GI tract. In addition, export of the adhesive moonlighting proteins mediated by EVs may promote bifidobacterial colonization. This study provides new insight into the roles of EVs in bifidobacterial colonization processes as these bacteria adapt to the GI environment.

RevDate: 2020-09-18
CmpDate: 2020-09-18

Liu XD, Lei HX, FF Chen (2019)

Infection pattern and negative effects of a facultative endosymbiont on its insect host are environment-dependent.

Scientific reports, 9(1):4013.

Regiella insecticola is a bacterial endosymbiont in insects that exhibits a negative effect on the fitness of hosts. Thus, it is not clear why this costly endosymbiont can persist in host populations. Here, we tested a hypothesis that the infection pattern and negative roles of the endosymbiont were not constant but environmentally dependent. The grain aphids Sitobion avenae, belonging to different genotypes and infected with Regiella or not, were used in this study. We found that S. avenae populations were infected with Regiella, Hamiltonella defensa, Serratia symbiotica and Rickettsia. The predominant endosymbionts in the aphid populations varied with season. Serratia and Rickettsia were predominant from December to February while Regiella predominated from March to May. The vertical transmission of Regiella was poorer at high temperature, but following conditioning for seven generations, the transmission rate improved. Regiella inhibited the production of winged aphids at 25 °C, but it did not affect winged morph production at the higher temperatures of 28 °C and 31 °C. Regiella infection decreased the intrinsic rate of increase (rm) of aphids at 25 °C and 28 °C. However, at 31 °C, the effect of Regiella on the rm varied depending on the aphid genotype and density. Thus, the negative effects of this endosymbiont on its host were environmentally dependent.

RevDate: 2020-09-17

Vilcinskas A, Schwabe M, Brinkrolf K, et al (2020)

Larvae of the Clothing Moth Tineola bisselliella Maintain Gut Bacteria that Secrete Enzyme Cocktails to Facilitate the Digestion of Keratin.

Microorganisms, 8(9): pii:microorganisms8091415.

The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth Tineola bisselliella provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to Bacillus sp. FDAARGOS_235. Genome annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of T. bisselliella larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.

RevDate: 2020-09-17
CmpDate: 2020-09-17

Agarwal K, Robinson LS, Aggarwal S, et al (2020)

Glycan cross-feeding supports mutualism between Fusobacterium and the vaginal microbiota.

PLoS biology, 18(8):e3000788.

Women with bacterial vaginosis (BV), an imbalance of the vaginal microbiome, are more likely to be colonized by potential pathogens such as Fusobacterium nucleatum, a bacterium linked with intrauterine infection and preterm birth. However, the conditions and mechanisms supporting pathogen colonization during vaginal dysbiosis remain obscure. We demonstrate that sialidase activity, a diagnostic feature of BV, promoted F. nucleatum foraging and growth on mammalian sialoglycans, a nutrient resource that was otherwise inaccessible because of the lack of endogenous F. nucleatum sialidase. In mice with sialidase-producing vaginal microbiotas, mutant F. nucleatum unable to consume sialic acids was impaired in vaginal colonization. These experiments in mice also led to the discovery that F. nucleatum may also "give back" to the community by reinforcing sialidase activity, a biochemical feature of human dysbiosis. Using human vaginal bacterial communities, we show that F. nucleatum supported robust outgrowth of Gardnerella vaginalis, a major sialidase producer and one of the most abundant organisms in BV. These results illustrate that mutually beneficial relationships between vaginal bacteria support pathogen colonization and may help maintain features of dysbiosis. These findings challenge the simplistic dogma that the mere absence of "healthy" lactobacilli is the sole mechanism that creates a permissive environment for pathogens during vaginal dysbiosis. Given the ubiquity of F. nucleatum in the human mouth, these studies also suggest a possible mechanism underlying links between vaginal dysbiosis and oral sex.

RevDate: 2020-09-17
CmpDate: 2020-09-17

Peralta JM, Travaglia CN, Romero-Puertas MC, et al (2020)

Unraveling the impact of arsenic on the redox response of peanut plants inoculated with two different Bradyrhizobium sp. strains.

Chemosphere, 259:127410.

Arsenic (As) can be present naturally in groundwater from peanut fields, constituting a serious problem, as roots can accumulate and mobilize the metalloid to their edible parts. Understanding the redox changes in the legume exposed to As may help to detect potential risks to human health and recognize tolerance mechanisms. Thirty-days old peanut plants inoculated with Bradyrhizobium sp. strains (SEMIA6144 or C-145) were exposed to a realistic arsenate concentration, in order to unravel the redox response and characterize the oxidative stress indexes. Thus, root anatomy, reactive oxygen species detection by fluorescence microscopy and, ROS histochemical staining along with the NADPH oxidase activity were analyzed. Besides, photosynthetic pigments and damage to lipids and proteins were determined as oxidative stress indicators. Results showed that at 3 μM AsV, the cross-section areas of peanut roots were augmented; NADPH oxidase activity was significantly increased and O2˙¯and H2O2 accumulated in leaves and roots. Likewise, an increase in the lipid peroxidation and protein carbonyls was also observed throughout the plant regardless the inoculated strain, while chlorophylls and carotenes were increased only in those inoculated with Bradyrhizobium sp. C-145. Interestingly, the oxidative burst, mainly induced by the NADPH oxidase activity, and the consequent oxidative stress was strain-dependent and organ-differential. Additionally, As modifies the root anatomy, acting as a possibly first defense mechanism against the metalloid entry. All these findings allowed us to conclude that the redox response of peanut is conditioned by the rhizobial strain, which contributes to the importance of effectively formulating bioinoculants for this crop.

RevDate: 2020-09-17
CmpDate: 2020-09-17

Zhang JQ, Zhou T, Xiao CH, et al (2020)

[Technical evaluation and principle analysis of simulative habitat cultivation of Dendrobium nobile].

Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica, 45(9):2042-2045.

The technique of "simulative habitat cultivation" is to preserve the quality of traditional Chinese medicine by simulating the original habitat and site environment of wild Chinese medicine resources. Dendrobium nobile is the most representative variety of traditional Chinese medicine which reflects the coordinated development of medicinal material production and ecological environment. In this paper, the main technical points of the simulated cultivation model of D. nobile were summarized as follows: rapid propagation of seedling tissue technology to ensure the genetic stability of provenance; line card+fermented cow manure+live moss method to improve the survival rate; epiphytic stone cultivation to improve the quality of medicinal materials; and the integration of mycorrhizal fungi to improve the quality stability of medicinal materials. On the basis of summarizing the ecological benefits, economical and social benefits generated by the application of the technology, the paper systematically analyzes the principle of the technology for the cultivation of D. nobile to promote the excellent quality, the light, gas, heat and fertilizer resources of the undergrowth niche are in line with the wild site environment of D. nobile. The rich and complex soil microbial community in the forest laid the foundation for the species diversity needed for the growth of D. nobile.The stress effect on the growth of D. nobile resulted in the accumulation of secondary metabolites. The symbiotic relationship between the symbiotic fungi such as bryophytes and D. nobile promotes the synthesis of plant secondary metabolites. The high quality D. nobile was produced efficiently by improving and optimizing the cultivation techniques.

RevDate: 2020-09-17
CmpDate: 2020-09-17

Becerra JE, Rodríguez-Díaz J, Gozalbo-Rovira R, et al (2020)

Unique Microbial Catabolic Pathway for the Human Core N-Glycan Constituent Fucosyl-α-1,6-N-Acetylglucosamine-Asparagine.

mBio, 11(1):.

The survival of commensal bacteria in the human gut partially depends on their ability to metabolize host-derived molecules. The use of the glycosidic moiety of N-glycoproteins by bacteria has been reported, but the role of N-glycopeptides or glycoamino acids as the substrates for bacterial growth has not been evaluated. We have identified in Lactobacillus casei strain BL23 a gene cluster (alf-2) involved in the catabolism of the glycoamino acid fucosyl-α-1,6-N-GlcNAc-Asn (6'FN-Asn), a constituent of the core-fucosylated structures of mammalian N-glycoproteins. The cluster consists of the genes alfHC, encoding a major facilitator superfamily (MFS) permease and the α-l-fucosidase AlfC, and the divergently oriented asdA (aspartate 4-decarboxylase), alfR2 (transcriptional regulator), pepV (peptidase), asnA2 (glycosyl-asparaginase), and sugK (sugar kinase) genes. Knockout mutants showed that alfH, alfC, asdA, asnA2, and sugK are necessary for efficient 6'FN-Asn utilization. The alf-2 genes are induced by 6'FN-Asn, but not by its glycan moiety, via the AlfR2 regulator. The constitutive expression of alf-2 genes in an alfR2 strain allowed the metabolism of a variety of 6'-fucosyl-glycans. However, GlcNAc-Asn did not support growth in this mutant background, indicating that the presence of a 6'-fucose moiety is crucial for substrate transport via AlfH. Within bacteria, 6'FN-Asn is defucosylated by AlfC, generating GlcNAc-Asn. This glycoamino acid is processed by the glycosylasparaginase AsnA2. GlcNAc-Asn hydrolysis generates aspartate and GlcNAc, which is used as a fermentable source by L.casei These data establish the existence in a commensal bacterial species of an exclusive metabolic pathway likely to scavenge human milk and mucosal fucosylated N-glycopeptides in the gastrointestinal tract.IMPORTANCE The gastrointestinal tract accommodates more than 1014 microorganisms that have an enormous impact on human health. The mechanisms enabling commensal bacteria and administered probiotics to colonize the gut remain largely unknown. The ability to utilize host-derived carbon and energy resources available at the mucosal surfaces may provide these bacteria with a competitive advantage in the gut. Here, we have identified in the commensal species Lactobacillus casei a novel metabolic pathway for the utilization of the glycoamino acid fucosyl-α-1,6-N-GlcNAc-Asn, which is present in the core-fucosylated N-glycoproteins from mammalians. These results give insight into the molecular interactions between the host and commensal/probiotic bacteria and may help to devise new strategies to restore gut microbiota homeostasis in diseases associated with dysbiotic microbiota.

RevDate: 2020-09-17
CmpDate: 2020-09-17

Martin H C, Ibáñez R, Nothias LF, et al (2019)

Viscosin-like lipopeptides from frog skin bacteria inhibit Aspergillus fumigatus and Batrachochytrium dendrobatidis detected by imaging mass spectrometry and molecular networking.

Scientific reports, 9(1):3019.

Amphibian populations worldwide have declined and in some cases become extinct due to chytridiomycosis, a pandemic disease caused by the fungus Batrachochytrium dendrobatidis; however, some species have survived these fungal epidemics. Previous studies have suggested that the resistance of these species is due to the presence of cutaneous bacteria producing antifungal metabolites. As our understanding of these metabolites is still limited, we assessed the potential of such compounds against human-relevant fungi such as Aspergillus. In this work we isolated 201 bacterial strains from fifteen samples belonging to seven frog species collected in the highlands of Panama and tested them against Aspergillus fumigatus. Among the 29 bacterial isolates that exhibited antifungal activity, Pseudomonas cichorii showed the greatest inhibition. To visualize the distribution of compounds and identify them in the inhibition zone produced by P. cichorii, we employed MALDI imaging mass spectrometry (MALDI IMS) and MS/MS molecular networking. We identified viscosin and massetolides A, F, G and H in the inhibition zone. Furthermore, viscosin was isolated and evaluated in vitro against A. fumigatus and B. dendrobatidis showing MIC values of 62.50 µg/mL and 31.25 µg/mL, respectively. This is the first report of cyclic depsipeptides with antifungal activity isolated from frog cutaneous bacteria.

RevDate: 2020-09-16

He C, Liu Y, Ye S, et al (2020)

Changes of intestinal microflora of breast cancer in premenopausal women.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology pii:10.1007/s10096-020-04036-x [Epub ahead of print].

Breast cancer is one of the most common malignant tumors in women. More than half of breast cancer patients are not menopausal at the time of diagnosis. The occurrence and development of premenopausal breast cancer are affected by many factors. Intestinal flora, especially SCFA-producing bacteria, participates in the development of various tumors, and there is a lack of in-depth research in premenopausal breast cancer patients. We used 16S rRNA gene sequencing, targeted metabolomics, and cell culture methods to analyze the changes in the intestinal flora and metabolites of premenopausal breast cancer patients. In addition, we treated breast cancer cells with significantly altered propionate and butyrate in vitro to examine their effects on cell activity. This study followed STROBE guidelines. We found that compared with healthy premenopausal women, the composition and symbiosis of intestinal flora in patients with premenopausal breast cancer changed significantly. The abundance of short-chain fatty acid (SCFA)-producing bacteria was significantly reduced, and the key SCFA-producing enzymes were also significantly reduced. Pediococcus and Desulfovibrio could distinguish premenopausal breast cancer patients from normal premenopausal women. The related propionate and butyrate had a certain ability to inhibit breast cancer cell viability in vitro. As SCFA-producing bacteria, Pediococcus and Desulfovibrio showed potential reference value for the diagnosis of premenopausal breast cancer. The ability of propionate and butyrate to inhibit breast cancer cell lines in vitro suggests that the relevant SCFA receptor may be a new target for the treatment of premenopausal breast cancer.

RevDate: 2020-09-16

Herrera M, Klein SG, Campana S, et al (2020)

Temperature transcends partner specificity in the symbiosis establishment of a cnidarian.

The ISME journal pii:10.1038/s41396-020-00768-y [Epub ahead of print].

Coral reef research has predominantly focused on the effect of temperature on the breakdown of coral-dinoflagellate symbioses. However, less is known about how increasing temperature affects the establishment of new coral-dinoflagellate associations. Inter-partner specificity and environment-dependent colonization are two constraints proposed to limit the acquisition of more heat tolerant symbionts. Here, we investigated the symbiotic dynamics of various photosymbionts in different host genotypes under "optimal" and elevated temperature conditions. To do this, we inoculated symbiont-free polyps of the sea anemone Exaiptasia pallida originating from Hawaii (H2), North Carolina (CC7), and the Red Sea (RS) with the same mixture of native symbiont strains (Breviolum minutum, Symbiodinium linucheae, S. microadriaticum, and a Breviolum type from the Red Sea) at 25 and 32 °C, and assessed their ITS2 composition, colonization rates, and PSII photochemical efficiency (Fv/Fm). Symbiont communities across thermal conditions differed significantly for all hosts, suggesting that temperature rather than partner specificity had a stronger effect on symbiosis establishment. Overall, we detected higher abundances of more heat resistant Symbiodiniaceae types in the 32 °C treatments. Our data further showed that PSII photophysiology under elevated temperature improved with thermal pre-exposure (i.e., higher Fv/Fm), yet, this effect depended on host genotype and was influenced by active feeding as photochemical efficiency dropped in response to food deprivation. These findings highlight the role of temperature and partner fidelity in the establishment and performance of symbiosis and demonstrate the importance of heterotrophy for symbiotic cnidarians to endure and recover from stress.

RevDate: 2020-09-16

Ibarra-Juarez LA, Burton MAJ, Biedermann PHW, et al (2020)

Evidence for Succession and Putative Metabolic Roles of Fungi and Bacteria in the Farming Mutualism of the Ambrosia Beetle Xyleborus affinis.

mSystems, 5(5): pii:5/5/e00541-20.

The bacterial and fungal community involved in ambrosia beetle fungiculture remains poorly studied compared to the famous fungus-farming ants and termites. Here we studied microbial community dynamics of laboratory nests, adults, and brood during the life cycle of the sugarcane shot hole borer, Xyleborus affinis We identified a total of 40 fungal and 428 bacterial operational taxonomic units (OTUs), from which only five fungi (a Raffaelea fungus and four ascomycete yeasts) and four bacterial genera (Stenotrophomonas, Enterobacter, Burkholderia, and Ochrobactrum) can be considered the core community playing the most relevant symbiotic role. Both the fungal and bacterial populations varied significantly during the beetle's life cycle. While the ascomycete yeasts were the main colonizers of the gallery early on, the Raffaelea and other filamentous fungi appeared after day 10, at the time when larval hatching happened. Regarding bacteria, Stenotrophomonas and Enterobacter dominated overall but decreased in foundresses and brood with age. Finally, inferred analyses of the putative metabolic capabilities of the bacterial microbiome revealed that they are involved in (i) degradation of fungal and plant polymers, (ii) fixation of atmospheric nitrogen, and (iii) essential amino acid, cofactor, and vitamin provisioning. Overall, our results suggest that yeasts and bacteria are more strongly involved in supporting the beetle-fungus farming symbiosis than previously thought.IMPORTANCE Ambrosia beetles farm their own food fungi within tunnel systems in wood and are among the three insect lineages performing agriculture (the others are fungus-farming ants and termites). In ambrosia beetles, primary ambrosia fungus cultivars have been regarded essential, whereas other microbes have been more or less ignored. Our KEGG analyses suggest so far unknown roles of yeasts and bacterial symbionts, by preparing the tunnel walls for the primary ambrosia fungi. This preparation includes enzymatic degradation of wood, essential amino acid production, and nitrogen fixation. The latter is especially exciting because if it turns out to be present in vivo in ambrosia beetles, all farming animals (including humans) are dependent on atmospheric nitrogen fertilization of their crops. As previous internal transcribed spacer (ITS) metabarcoding approaches failed on covering the primary ambrosia fungi, our 18S metabarcoding approach can also serve as a template for future studies on the ambrosia beetle-fungus symbiosis.

RevDate: 2020-09-16

Francoeur CB, Khadempour L, Moreira-Soto RD, et al (2020)

Bacteria Contribute to Plant Secondary Compound Degradation in a Generalist Herbivore System.

mBio, 11(5): pii:mBio.02146-20.

Herbivores must overcome a variety of plant defenses, including coping with plant secondary compounds (PSCs). To help detoxify these defensive chemicals, several insect herbivores are known to harbor gut microbiota with the metabolic capacity to degrade PSCs. Leaf-cutter ants are generalist herbivores, obtaining sustenance from specialized fungus gardens that act as external digestive systems and which degrade the diverse collection of plants foraged by the ants. There is in vitro evidence that certain PSCs harm Leucoagaricus gongylophorus, the fungal cultivar of leaf-cutter ants, suggesting a role for the Proteobacteria-dominant bacterial community present within fungus gardens. In this study, we investigated the ability of symbiotic bacteria present within fungus gardens of leaf-cutter ants to degrade PSCs. We cultured fungus garden bacteria, sequenced the genomes of 42 isolates, and identified genes involved in PSC degradation, including genes encoding cytochrome P450 enzymes and genes in geraniol, cumate, cinnamate, and α-pinene/limonene degradation pathways. Using metatranscriptomic analysis, we showed that some of these degradation genes are expressed in situ Most of the bacterial isolates grew unhindered in the presence of PSCs and, using gas chromatography-mass spectrometry (GC-MS), we determined that isolates from the genera Bacillus, Burkholderia, Enterobacter, Klebsiella, and Pseudomonas degrade α-pinene, β-caryophyllene, or linalool. Using a headspace sampler, we show that subcolonies of fungus gardens reduced α-pinene and linalool over a 36-h period, while L. gongylophorus strains alone reduced only linalool. Overall, our results reveal that the bacterial communities in fungus gardens play a pivotal role in alleviating the effect of PSCs on the leaf-cutter ant system.IMPORTANCE Leaf-cutter ants are dominant neotropical herbivores capable of deriving energy from a wide range of plant substrates. The success of leaf-cutter ants is largely due to their external gut, composed of key microbial symbionts, specifically, the fungal mutualist L. gongylophorus and a consistent bacterial community. Both symbionts are known to have critical roles in extracting energy from plant material, yet comparatively little is known about their roles in the detoxification of plant secondary compounds. In this study, we assessed if the bacterial communities associated with leaf-cutter ant fungus gardens can degrade harmful plant chemicals. We identify plant secondary compound detoxification in leaf-cutter ant gardens as a process that depends on the degradative potential of both the bacterial community and L. gongylophorus Our findings suggest that the fungus garden and its associated microbial community influence the generalist foraging abilities of the ants, underscoring the importance of microbial symbionts in plant substrate suitability for herbivores.

RevDate: 2020-09-16

Kovaleva O, Podlesnaya P, Rashidova M, et al (2020)

Lung Microbiome Differentially Impacts Survival of Patients with Non-Small Cell Lung Cancer Depending on Tumor Stroma Phenotype.

Biomedicines, 8(9): pii:biomedicines8090349.

The link between a lung tumor and the lung microbiome is a largely unexplored issue. To investigate the relationship between a lung microbiome and the phenotype of an inflammatory stromal infiltrate, we studied a cohort of 89 patients with non-small cell lung cancer. The microbiome was analyzed in tumor and adjacent normal tissue by 16S rRNA amplicon sequencing. Characterization of the tumor stroma was done using immunohistochemistry. We demonstrated that the bacterial load was higher in adjacent normal tissue than in a tumor (p = 0.0325) with similar patterns of taxonomic structure and alpha diversity. Lung adenocarcinomas did not differ in their alpha diversity from squamous cell carcinomas, although the content of Gram-positive bacteria increased significantly in the adenocarcinoma group (p = 0.0419). An analysis of an inflammatory infiltrate of tumor stroma showed a correlation of CD68, iNOS and FOXP3 with a histological type of tumor. For the first time we showed that high bacterial load in the tumor combined with increased iNOS expression is a favorable prognostic factor (HR = 0.1824; p = 0.0123), while high bacterial load combined with the increased number of FOXP3+ cells is a marker of poor prognosis (HR = 4.651; p = 0.0116). Thus, we established that bacterial load of the tumor has an opposite prognostic value depending on the status of local antitumor immunity.

RevDate: 2020-09-15

Wanke A, Malisic M, Wawra S, et al (2020)

Unraveling the sugar code: the role of microbial extracellular glycans in plant-microbe interactions.

Journal of experimental botany pii:5905709 [Epub ahead of print].

To defend against microbial invaders but also to establish symbiotic programs, plants need to detect the presence of microbes through the perception of molecular signatures characteristic of a whole class of microbes. Among these molecular signatures, extracellular glycans represent a structurally complex and diverse group of biomolecules that has a pivotal role in the molecular dialogue between plants and microbes. Secreted glycans and glycoconjugates like symbiotic lipochitooligosaccharides or immunosuppressive cyclic β-glucans act as microbial messengers that prepare the ground for host colonization. On the other hand, microbial cell-surface glycans are important indicators of microbial presence. They are conserved structures normally exposed and thus accessible for plant hydrolytic enzymes and cell-surface receptor proteins. While the immunogenic potential of bacterial cell-surface glycoconjugates such as lipopolysaccharides and peptidoglycan has been intensively studied in the past years, perception of cell-surface glycans from filamentous microbes such as fungi or oomycetes is still largely unexplored. To date, only few studies have focused on the role of fungal-derived cell-surface glycans other than chitin, highlighting a knowledge gap that needs to be addressed. The objective of this review is to give an overview on the biological functions and perception of microbial extracellular glycans, primarily focusing on their recognition and their contribution to plant-microbe interactions.

RevDate: 2020-09-16
CmpDate: 2020-09-15

Levy O, Fernandes de Barros Marangoni L, I C Benichou J, et al (2020)

Artificial light at night (ALAN) alters the physiology and biochemistry of symbiotic reef building corals.

Environmental pollution (Barking, Essex : 1987), 266(Pt 2):114987.

Artificial Light at Night (ALAN), which is the alteration of natural light levels as the result of anthropogenic light sources, has been acknowledged as an important factor that alters the functioning of marine ecosystems. Using LEDs light to mimic ALAN, we studied the effect on the physiology (symbiont and chlorophyll contents, photosynthesis, respiration, pigment profile, skeletal growth, and oxidative stress responses) of two scleractinian coral species originating from the Red Sea. ALAN induced the photoinhibition of symbiont photosynthesis, as well as an overproduction of reactive oxygen species (ROS) and an increase in oxidative damage to lipids in both coral species. The extent of the deleterious effects of ALAN on the symbiotic association and coral physiology was aligned with the severity of the oxidative stress condition experienced by the corals. The coral species Sylophora pistillata, which experienced a more severe oxidative stress condition than the other species tested, Turbinaria reniformis, also showed a more pronounced bleaching (loss of symbionts and chlorophyll content), enhanced photoinhibition and decreased photosynthetic rates. Findings of the present study further our knowledge on the biochemical mechanisms underpinning the deleterious impacts of ALAN on scleractinian corals, ultimately shedding light on the emerging threat of ALAN on coral reef ecology. Further, considering that global warming and light pollution will increase in the next few decades, future studies should be taken to elucidate the potential synergetic effects of ALAN and global climate change stressors.

RevDate: 2020-09-15
CmpDate: 2020-09-15

Wang X, Zhu X, Bi Y, et al (2020)

Dynamics of microbial community and changes of metabolites during production of type Ι sourdough steamed bread made by retarded sponge-dough method.

Food chemistry, 330:127316.

Dynamics of microbial community and changes of metabolites during production of type Ι sourdough steamed bread made by retarded sponge-dough method (SSB) were studied. Lactobacillus sanfranciscensis and Lactobacillus pontis were the dominant bacterial species. Particularly, relative abundances of Lactobacillus sanfranciscensis were significantly higher than that of other sub-dominant bacterial species. The dominant fungal species were Saccharomyces cerevisiae and Kazachstania humilis, and the latter was the most predominant. A stable bacterial and fungal consortia was established in sponge dough retarded from 12 to 24 h and main dough proofed from 30 to 60 min. Metabolism preference for maltose of Lactobacillus sanfranciscensis favoured a mutualistic association with maltose-negative Kazachstania humilis, and hence contributing to their competitiveness and dominance. Volatile compounds became more abundant with much more esters as sponge retarding time extended. Probably, the accumulation of organic acids and ethanol contributed mostly to formation of ethyl esters in sponge dough during retarding.

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

Gwida M, Awad A, El-Ashker M, et al (2020)

Microarray-based detection of resistance and virulence factors in commensal Escherichia coli from livestock and farmers in Egypt.

Veterinary microbiology, 240:108539.

The objective of our study was to provide a molecular analysis using DNA-microarray based assays of commensal E. coli populations from apparently healthy livestock and their attendants to assess the virulence potential as well as multidrug resistance (MDR) genotypes. We randomly collected 132 fecal samples from seemingly healthy smallholder´s food producing animals [buffalo (n = 32) and cattle (n = 50)] as well as from contacting farmers (n = 50). Bacterial isolation and identification were performed using standard protocols, while E. coli isolates were characterized using a DNA microarray system targeting 60 different virulence and 47 antibiotic resistance genes of clinical importance and allowing assignment to most common H and O types. From the fecal samples examined, 47 E. coli isolates were obtained. The array predicted serotypes for 14 out of the 47 E. coli isolates. Six E. coli isolates were identified as STEC since Shiga toxin genes were detected. In summary, 36 different virulence genes were identified; of which, hemL, lpfA and iss were most prevalent. Thirty-four E. coli isolates were found to carry at least one antimicrobial resistance gene. Of these, 20 did exhibit genes allowing strain classification as MDR. More than half of the isolates contained antimicrobial resistance genes associated with beta lactam resistance 27/47 (57.5 %). The 13 remaining isolates did not contain any resistance gene tested with the array. Our study demonstrated the presence of antimicrobial resistance genes and virulence genotypes among commensal E. coli of human and animal sources.

RevDate: 2020-09-15
CmpDate: 2020-09-15

Brunel C, Beifen Y, Pouteau R, et al (2020)

Responses of Rhizospheric Microbial Communities of Native and Alien Plant Species to Cuscuta Parasitism.

Microbial ecology, 79(3):617-630.

Parasitic plants have major impacts on host fitness. In the case of species of the holoparasitic Cuscuta genus, these impacts were shown to be particularly strong in some invasive alien plants, which has raised interest in the underlying mechanism. We hypothesized that Cuscuta parasitization may exert strong influence in shaping the diversity patterns in the host rhizosphere microbiome and that this may vary between native (coevolved) and alien (non-coevolved) plants. Here, we report on a field study exploring the effect of parasitization by Cuscuta australis on the rhizosphere microbiota (16S and ITS rDNA) of four plant species sharing and three plant species not sharing the parasite's native range. Despite a predominant role of the host species in shaping the rhizosphere microbiota, the role of host origin and of parasitization still appeared important in structuring microbial communities and their associated functions. Bacterial communities were more strongly influenced than fungi by the native range of the host plant, while fungi were slightly more affected than bacteria by parasitization. About 7% of bacterial phylotypes and 11% of fungal phylotypes were sensitive to Cuscuta parasitization. Parasitization also reduced the abundance of arbuscular mycorrhizal fungi by ca. 18% and of several genes related to plant growth promoting functions (e.g., nitrogen metabolism and quorum sensing). Both fungi and bacteria differentially responded to host parasitization depending on host origin, and the extent of these shifts suggests that they may have more dramatic consequences for alien than for native plants.

RevDate: 2020-09-15
CmpDate: 2020-09-15

Li F, Li P, Hua H, et al (2020)

Diversity, Tissue Localization, and Infection Pattern of Bacterial Symbionts of the White-Backed Planthopper, Sogatella furcifera (Hemiptera: Delphacidae).

Microbial ecology, 79(3):720-730.

The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is a destructive pest of rice. Bacterial symbionts play an important role in insect hosts, especially hemipteran hosts. This study was designed to examine the bacterial symbionts of the WBPH using 16S rDNA high-throughput sequencing. A total of 63 and 177 operational taxonomic units (OTUs) were identified in females and males of three WBPH populations, respectively. These OTUs included bacteria of 75 genera from 11 phyla, where Wolbachia, Cardinium, and Asaia were the dominant genera, accounting for over 97.99% of all the symbiotic bacteria. Fluorescence in situ hybridization detected Wolbachia, Cardinium, and Asaia in the salivary glands, guts, testes, and eggs of the WBPH, indicating the potential for both horizontal and vertical transmission. Moreover, the infection pattern of the three dominant bacterial symbionts was detected in six WBPH populations. The frequencies of Wolbachia infection of females and Cardinium infection of both sexes were over 96.7%. Wolbachia infection of males ranged between 46.7 and 63.3%, which was significantly lower than that observed for females. Asaia infection of both sexes varied substantially among the populations. These results indicate that the complex host-symbiotic bacteria interaction is influenced by host sex and geographical origin and potentially by the transmission modes of the symbionts.

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

Jones AG, Mason CJ, Felton GW, et al (2019)

Host plant and population source drive diversity of microbial gut communities in two polyphagous insects.

Scientific reports, 9(1):2792.

Symbioses between insects and microbes are ubiquitous, but vary greatly in terms of function, transmission mechanism, and location in the insect. Lepidoptera (butterflies and moths) are one of the largest and most economically important insect orders; yet, in many cases, the ecology and functions of their gut microbiomes are unresolved. We used high-throughput sequencing to determine factors that influence gut microbiomes of field-collected fall armyworm (Spodoptera frugiperda) and corn earworm (Helicoverpa zea). Fall armyworm midgut bacterial communities differed from those of corn earworm collected from the same host plant species at the same site. However, corn earworm bacterial communities differed between collection sites. Subsequent experiments using fall armyworm evaluating the influence of egg source and diet indicated that that host plant had a greater impact on gut communities. We also observed differences between regurgitant (foregut) and midgut bacterial communities of the same insect host, suggesting differential colonization. Our findings indicate that host plant is a major driver shaping gut microbiota, but differences in insect physiology, gut region, and local factors can also contribute to variation in microbiomes. Additional studies are needed to assess the mechanisms that affect variation in insect microbiomes, as well as the ecological implications of this variability in caterpillars.

RevDate: 2020-09-14

Wang YW, Hess J, Slot JC, et al (2020)

De novo gene birth, horizontal gene transfer and gene duplication as sources of new gene families associated with the origin of symbiosis in Amanita.

Genome biology and evolution pii:5905478 [Epub ahead of print].

By introducing novel capacities and functions, new genes and gene families may play a crucial role in ecological transitions. Mechanisms generating new gene families include de novo gene birth, horizontal gene transfer and neofunctionalization following a duplication event. The ectomycorrhizal (ECM) symbiosis is a ubiquitous mutualism and the association has evolved repeatedly and independently many times among the fungi, but the evolutionary dynamics enabling its emergence remain elusive. We developed a phylogenetic workflow to first understand if gene families unique to ECM Amanita fungi and absent from closely related asymbiotic species are functionally relevant to the symbiosis, and then to systematically infer their origins. We identified 109 gene families unique to ECM Amanita species. Genes belonging to unique gene families are under strong purifying selection and are upregulated during symbiosis, compared to genes of conserved or orphan gene families. The origins of seven of the unique gene families are strongly supported as either de novo gene birth (two gene families), horizontal gene transfer (four), and gene duplication (one). An additional 34 families appear new because of their selective retention within symbiotic species. Among the 109 unique gene families, the most upregulated gene in symbiotic cultures encodes an ACC deaminase, an enzyme capable of downregulating the synthesis of the plant hormone ethylene, a common negative regulator of plant-microbial mutualisms.

RevDate: 2020-09-14

Jensen RE, Cabral C, Enkegaard A, et al (2020)

Influence of the plant interacting entomopathogenic fungus Beauveria bassiana on parasitoid host choice-behavior, development, and plant defense pathways.

PloS one, 15(9):e0238943 pii:PONE-D-20-10979.

Inoculating plants with entomopathogenic fungi may influence plant nutrient uptake and growth, and herbivore performance. Knowledge is limited concerning the effects of this symbiosis on higher trophic levels. We examined how fungal treatment of faba bean seeds with the entomopathogenic fungus Beauveria bassiana influenced the choice-behavior and development of the aphid parasitoid Aphidius colemani. We also sampled plant material for analysis of changes in expression of genes related to plant defense pathways. While parasitoids were compatible with plants inoculated with B. bassiana initially (66 vs. 65% parasitization on inoculated and control plants, respectively; similar development times of parasitoids: 9.2 days), the emergence of adult parasitoids originating from aphids on fungus treated plants was significantly lower (67 vs. 76%, respectively). We also found that the defense response changed, similar to induced systemic resistance, when plants were treated with B. bassiana, similarly to what has been found for other plant symbiotic microorganisms. These novel findings show that although the application of entomopathogenic fungi to plants can alter the plants' defense against herbivores, it may also have an impact on beneficial insects, so their function and use should be evaluated on a case-by-case basis.

RevDate: 2020-09-14

Gonçalves WG, Fernandes KM, Silva APA, et al (2020)

Ultrastructure of the Bacteriocytes in the Midgut of the Carpenter ant Camponotus rufipes: Endosymbiont Control by Autophagy.

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada pii:S1431927620024484 [Epub ahead of print].

The carpenter ant Camponotus rufipes has intracellular bacteria in bacteriocytes scattered in the midgut epithelium, which have different amounts of endosymbionts, according to the developmental stages. However, there are no detailed data about the midgut cells in adult workers. The present work aimed to evaluate the morphology and cellular events that coordinate the abundance of endosymbionts in the midgut cells in C. rufipes workers. The midgut epithelium has digestive cells, bacteriocytes, and cells with intermediate morphology. The latter is similar to bacteriocytes, due to the abundance of endosymbionts, and similar to digestive cells, due to their microvilli. The digestive and intermediate cells are rich in autophagosomes and autolysosomes, both with bacteria debris in the lumen. These findings suggest that midgut cells of C. rufipes control the endosymbiont level by the autophagy pathway.

RevDate: 2020-09-14

Bartlow AW, SJ Agosta (2020)

Phoresy in animals: review and synthesis of a common but understudied mode of dispersal.

Biological reviews of the Cambridge Philosophical Society [Epub ahead of print].

Phoresy is a type of interaction in which one species, the phoront, uses another species, the dispersal host, for transportation to new habitats or resources. Despite being a widespread behaviour, little is known about the ecology and evolution of phoresy. Our goal is to provide a comprehensive review of phoretic dispersal in animals and to bring renewed attention to this subject. We surveyed literature published between 1900 and 2020 to understand the extent of known higher-level taxonomic diversity (phyla, classes, and orders) and functional aspects of animals that use phoretic dispersal. Species dispersing phoretically have been observed in at least 13 animal phyla, 25 classes, and 60 orders. The majority of known phoronts are arthropods (Phylum Euarthropoda) in terrestrial habitats, but phoronts also occur in freshwater and marine environments. Marine phoronts may be severely under-represented in the literature due to the relative difficulty of studying these systems. Phoronts are generally small with low mobility and use habitats or resources that are ephemeral and/or widely dispersed. Many phoronts are also parasites. In general, animals that engage in phoresy use a wide variety of morphological and behavioural traits for locating, attaching to, and detaching from dispersal hosts, but the exact mechanisms behind these activities are largely unknown. In addition to diversity, we discuss the evolution of phoresy including the long-standing idea that it can be a precursor to parasitism and other forms of symbioses. Finally, we suggest several areas of future research to improve our understanding of phoresy and its ecological and evolutionary significance.

RevDate: 2020-09-14

Wei X, Chen J, Zhang C, et al (2020)

Ericoid mycorrhizal fungus enhances microcutting rooting of Rhododendron fortunei and subsequent growth.

Horticulture research, 7:140 pii:361.

Adventitious root (AR) formation is a unique feature of plant reproduction and plays a vital role in crop production as many horticultural and forestry plants are propagated through cuttings. A growing number of reports have shown that microbes, particularly mycorrhizal fungi are able to promote AR formation, but the underlying mechanisms remain largely unclear. This study established an in vitro culture system and investigated AR formation in microcuttings of Rhododendron fortunei Lindl. inoculated with Oidiodendron maius Barron Om19, an ericoid mycorrhizal fungus strain. Hormones and precursors involved in the biosynthesis of indole-3-acetic acid (IAA) in Om19 mycelium were analyzed. Om19 was able to produce a large quantity of tryptophan (Trp) and also indole-3-pyruvate (IPA) and IAA, indicating that IAA biosynthesis in Om19 could be through a Trp-dependent pathway. After inoculation of Om19, ARs were quickly formed in microcuttings. Symbiosis related genes were activated in ARs, and Om19 effectively colonized the roots. YUC3, a key gene in plant biosynthesis of IAA and genes involved in nitrogen (N) uptake and metabolism, phosphorus (P) uptake were highly upregulated. Plants absorbed significantly greater quantity of mineral nutrients, and their growth was substantially enhanced compared to the control plants without Om19 inoculation. A working model for Om19 enhanced AR formation was proposed. The rapid formation of ARs in cuttings could be due in part to the induction of IAA biosynthesized by Om19 and also attributed to Trp catalyzed biosynthesis of IAA in plants. AR formation, in turn, provided Om19 preferred sites for colonization. Our study suggested that in addition to promoting AR formation, Om19 could potentially be used as a new biofertilizer for enhancing production of ericaceous plants, such as blueberry, cranberry, and rhododendron.

RevDate: 2020-09-14

Røy H, Vopel K, Huettel M, et al (2009)

Sulfide assimilation by ectosymbionts of the sessile ciliate, Zoothamnium niveum.

Marine biology, 156(4):669-677.

We investigated the constraints on sulfide uptake by bacterial ectosymbionts on the marine peritrich ciliate Zoothamnium niveum by a combination of experimental and numerical methods. Protists with symbionts were collected on large blocks of mangrove-peat. The blocks were placed in a flow cell with flow adjusted to in situ velocity. The water motion around the colonies was then characterized by particle tracking velocimetry. This shows that the feather-shaped colony of Z. niveum generates a unidirectional flow of seawater through the colony with no recirculation. The source of the feeding current was the free-flowing water although the size of the colonies suggests that they live partly submerged in the diffusive boundary layer. We showed that the filtered volume allows Z. niveum to assimilate sufficient sulfide to sustain the symbiosis at a few micromoles per liter in ambient concentration. Numerical modeling shows that sulfide oxidizing bacteria on the surfaces of Z. niveum can sustain 100-times higher sulfide uptake than bacteria on flat surfaces, such as microbial mats. The study demonstrates that the filter feeding zooids of Z. niveum are preadapted to be prime habitats for sulfide oxidizing bacteria due to Z. niveum's habitat preference and due to the feeding current. Z. niveum is capable of exploiting low concentrations of sulfide in near norm-oxic seawater. This links its otherwise dissimilar habitats and makes it functionally similar to invertebrates with thiotrophic symbionts in filtering organs.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Li H, Limenitakis JP, Greiff V, et al (2020)

Mucosal or systemic microbiota exposures shape the B cell repertoire.

Nature, 584(7820):274-278.

Colonization by the microbiota causes a marked stimulation of B cells and induction of immunoglobulin, but mammals colonized with many taxa have highly complex and individualized immunoglobulin repertoires1,2. Here we use a simplified model of defined transient exposures to different microbial taxa in germ-free mice3 to deconstruct how the microbiota shapes the B cell pool and its functional responsiveness. We followed the development of the immunoglobulin repertoire in B cell populations, as well as single cells by deep sequencing. Microbial exposures at the intestinal mucosa generated oligoclonal responses that differed from those of germ-free mice, and from the diverse repertoire that was generated after intravenous systemic exposure to microbiota. The IgA repertoire-predominantly to cell-surface antigens-did not expand after dose escalation, whereas increased systemic exposure broadened the IgG repertoire to both microbial cytoplasmic and cell-surface antigens. These microbial exposures induced characteristic immunoglobulin heavy-chain repertoires in B cells, mainly at memory and plasma cell stages. Whereas sequential systemic exposure to different microbial taxa diversified the IgG repertoire and facilitated alternative specific responses, sequential mucosal exposure produced limited overlapping repertoires and the attrition of initial IgA binding specificities. This shows a contrast between a flexible response to systemic exposure with the need to avoid fatal sepsis, and a restricted response to mucosal exposure that reflects the generic nature of host-microbial mutualism in the mucosa.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Hewitt KG, Mace WJ, McKenzie CM, et al (2020)

Fungal Alkaloid Occurrence in Endophyte-Infected Perennial Ryegrass during Seedling Establishment.

Journal of chemical ecology, 46(4):410-421.

The symbiotic Epichloë festucae var. lolii endophyte produces alkaloids which can provide its host grass, perennial ryegrass (Lolium perenne L), with a selective advantage in both natural and agricultural managed ecosystems. This study focuses on understanding the alkaloid concentrations that occur in endophyte-infected perennial ryegrass during the early establishment phase. In a glasshouse experiment fungal alkaloid concentrations (peramine, lolitrem B, ergovaline, and epoxy-janthitrems) were measured in perennial ryegrass seedlings infected with E. festucae var. lolii proprietary strains AR1, AR37, NEA2, and NZ common toxic for 69 days after sowing. The endophyte becomes metabolically active, starting alkaloid production, as early as 6 days after sowing. Alkaloid concentrations peaked in 8- to 10- day-old seedlings due to a seedling growth slowdown. This study provides data showing that the loss of insect protection in endophyte-infected seedlings is linked to a reduction in chemical defence after seed-stored, maternally synthesised alkaloids are diluted by seedling dry matter accumulation.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Fuchs B, Kuhnert E, J Krauss (2020)

Contrasting Effects of Grass - Endophyte Chemotypes on a Tri-Trophic Cascade.

Journal of chemical ecology, 46(4):422-429.

Systemic grass-endophytes of the genus Epichloë symbiotically infect the above-ground plant parts of many grass species, where they produce alkaloids in a grass- and endophyte-specific manner that are toxic or deterrent to herbivores. An increasing number of studies show cascading negative effects of endophyte-derived alkaloids that extend to higher trophic levels, harming beneficial insects, including those that control aphid populations. Lacewings are one of the major biological aphid controls, and are especially resistant to insecticides and pollutants, but their susceptibility to endophyte infection in the food chain has never been studied. Our study found variability in aphid population growth depending on the endophyte-grass chemotype, where aphid population growth was lowest on chemotypes known for producing high amounts of loline alkaloids. We also showed that larval and pupal development and mortality of the Common Green Lacewing (Chrysoperla carnea) was, in a non-choice experiment, not affected by endophyte infection in the food chain. This is a first indication that lacewings might be resistant to endophyte-derived alkaloids and could be robust biocontrol agents when applied together with endophyte-infected grass, possibly replacing chemical pesticides.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Spribille T, Tagirdzhanova G, Goyette S, et al (2020)

3D biofilms: in search of the polysaccharides holding together lichen symbioses.

FEMS microbiology letters, 367(5):.

Stable, long-term interactions between fungi and algae or cyanobacteria, collectively known as lichens, have repeatedly evolved complex architectures with little resemblance to their component parts. Lacking any central scaffold, the shapes they assume are casts of secreted polymers that cement cells into place, determine the angle of phototropic exposure and regulate water relations. A growing body of evidence suggests that many lichen extracellular polymer matrices harbor unicellular, non-photosynthesizing organisms (UNPOs) not traditionally recognized as lichen symbionts. Understanding organismal input and uptake in this layer is key to interpreting the role UNPOs play in lichen biology. Here, we review both polysaccharide composition determined from whole, pulverized lichens and UNPOs reported from lichens to date. Most reported polysaccharides are thought to be structural cell wall components. The composition of the extracellular matrix is not definitively known. Several lines of evidence suggest some acidic polysaccharides have evaded detection in routine analysis of neutral sugars and may be involved in the extracellular matrix. UNPOs reported from lichens include diverse bacteria and yeasts for which secreted polysaccharides play important biological roles. We conclude by proposing testable hypotheses on the role that symbiont give-and-take in this layer could play in determining or modifying lichen symbiotic outcomes.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Treanor D, WOH Hughes (2019)

Limited female dispersal predicts the incidence of Wolbachia across ants (Hymenoptera: Formicidae).

Journal of evolutionary biology, 32(10):1163-1170.

The endosymbiotic bacterium Wolbachia is perhaps the greatest panzootic in the history of life on Earth, yet remarkably little is known regarding the factors that determine its incidence across species. One possibility is that Wolbachia more easily invades species with structured populations, due to the increased strength of genetic drift and higher initial frequency of infection. This should enable strains that induce mating incompatibilities to more easily cross the threshold prevalence above which they spread to either fixation or a stable equilibrium infection prevalence. Here, we provide empirical support for this hypothesis by analysing the relationship between female dispersal (as a proxy for population structure) and the incidence of Wolbachia across 250 species of ants. We show that species in which the dispersal of reproductive females is limited are significantly more likely to be infected with Wolbachia than species whose reproductive ecology is consistent with significant dispersal of females, and that this relationship remains after controlling for host phylogeny. We suggest that structured host populations, in this case resulting from limited female dispersal, may be an important feature determining how easily Wolbachia becomes successfully established in a novel host, and thus its occurrence across a wide diversity of invertebrate hosts.

RevDate: 2020-09-12

Okubo N, Tamura-Nakano M, T Watanabe (2020)

Experimental observation of microplastics invading the endoderm of anthozoan polyps.

Marine environmental research, 162:105125 pii:S0141-1136(20)30387-1 [Epub ahead of print].

Coral reefs are being degraded worldwide by land reclamation and environmental factors, such as high seawater temperature, resulting in mass bleaching events. In addition, microplastics disturb the formation of coral-algae symbiotic relationships in primary polyps. In our experiments, we observed this effect in the bleached primary polyp Seriatopora caliendrum that lost its symbiont Symbiodiniaceae as a result of high water temperature. There was a higher incorporation of microspheres into bleached corals than in healthy ones. To understand the interference in symbiosis, we used the sea anemone Exaiptasia (as an anthozoan model organism) and fed it with microspheres. TEM results suggested the incorporation of microspheres and symbionts from the same phagocytosis zones in the mesenterial filament and endocytosis by the cells. In the tentacles, microspheres were in the same cell layer as the symbionts. These results suggest that microplastics occupy the spaces inhabited by Symbiodiniaceae, thereby hindering their symbiotic association.

RevDate: 2020-09-12

Budnick JA, Sheehan LM, Ginder MJ, et al (2020)

A central role for the transcriptional regulator VtlR in small RNA-mediated gene regulation in Agrobacterium tumefaciens.

Scientific reports, 10(1):14968 pii:10.1038/s41598-020-72117-0.

LysR-type transcriptional regulators (LTTRs) are the most common type of transcriptional regulators in prokaryotes and function by altering gene expression in response to environmental stimuli. In the class Alphaproteobacteria, a conserved LTTR named VtlR is critical to the establishment of host-microbe interactions. In the mammalian pathogen Brucella abortus, VtlR is required for full virulence in a mouse model of infection, and VtlR activates the expression of abcR2, which encodes a small regulatory RNA (sRNA). In the plant symbiont Sinorhizobium meliloti, the ortholog of VtlR, named LsrB, is involved in the symbiosis of the bacterium with alfalfa. Agrobacterium tumefaciens is a close relative of both B. abortus and S. meliloti, and this bacterium is the causative agent of crown gall disease in plants. In the present study, we demonstrate that VtlR is involved in the ability of A. tumefaciens to grow appropriately in artificial medium, and an A. tumefaciens vtlR deletion strain is defective in motility, biofilm formation, and tumorigenesis of potato discs. RNA-sequencing analyses revealed that more than 250 genes are dysregulated in the ∆vtlR strain, and importantly, VtlR directly controls the expression of three sRNAs in A. tumefaciens. Taken together, these data support a model in which VtlR indirectly regulates hundreds of genes via manipulation of sRNA pathways in A. tumefaciens, and moreover, while the VtlR/LsrB protein is present and structurally conserved in many members of the Alphaproteobacteria, the VtlR/LsrB regulatory circuitry has diverged in order to accommodate the unique environmental niche of each organism.

RevDate: 2020-09-12

Martinson VG (2020)

Rediscovering a Forgotten System of Symbiosis: Historical Perspective and Future Potential.

Genes, 11(9): pii:genes11091063.

While the majority of symbiosis research is focused on bacteria, microbial eukaryotes play important roles in the microbiota and as pathogens, especially the incredibly diverse Fungi kingdom. The recent emergence of widespread pathogens in wildlife (bats, amphibians, snakes) and multidrug-resistant opportunists in human populations (Candida auris) has highlighted the importance of better understanding animal-fungus interactions. Regardless of their prominence there are few animal-fungus symbiosis models, but modern technological advances are allowing researchers to utilize novel organisms and systems. Here, I review a forgotten system of animal-fungus interactions: the beetle-fungus symbioses of Drugstore and Cigarette beetles with their symbiont Symbiotaphrina. As pioneering systems for the study of mutualistic symbioses, they were heavily researched between 1920 and 1970, but have received only sporadic attention in the past 40 years. Several features make them unique research organisms, including (1) the symbiont is both extracellular and intracellular during the life cycle of the host, and (2) both beetle and fungus can be cultured in isolation. Specifically, fungal symbionts intracellularly infect cells in the larval and adult beetle gut, while accessory glands in adult females harbor extracellular fungi. In this way, research on the microbiota, pathogenesis/infection, and mutualism can be performed. Furthermore, these beetles are economically important stored-product pests found worldwide. In addition to providing a historical perspective of the research undertaken and an overview of beetle biology and their symbiosis with Symbiotaphrina, I performed two analyses on publicly available genomic data. First, in a preliminary comparative genomic analysis of the fungal symbionts, I found striking differences in the pathways for the biosynthesis of two B vitamins important for the host beetle, thiamine and biotin. Second, I estimated the most recent common ancestor for Drugstore and Cigarette beetles at 8.8-13.5 Mya using sequence divergence (CO1 gene). Together, these analyses demonstrate that modern methods and data (genomics, transcriptomes, etc.) have great potential to transform these beetle-fungus systems into model systems again.

RevDate: 2020-09-12

Pereira AC, Ramos B, Reis AC, et al (2020)

Non-Tuberculous Mycobacteria: Molecular and Physiological Bases of Virulence and Adaptation to Ecological Niches.

Microorganisms, 8(9): pii:microorganisms8091380.

Non-tuberculous mycobacteria (NTM) are paradigmatic colonizers of the total environment, circulating at the interfaces of the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere. Their striking adaptive ecology on the interconnection of multiple spheres results from the combination of several biological features related to their exclusive hydrophobic and lipid-rich impermeable cell wall, transcriptional regulation signatures, biofilm phenotype, and symbiosis with protozoa. This unique blend of traits is reviewed in this work, with highlights to the prodigious plasticity and persistence hallmarks of NTM in a wide diversity of environments, from extreme natural milieus to microniches in the human body. Knowledge on the taxonomy, evolution, and functional diversity of NTM is updated, as well as the molecular and physiological bases for environmental adaptation, tolerance to xenobiotics, and infection biology in the human and non-human host. The complex interplay between individual, species-specific and ecological niche traits contributing to NTM resilience across ecosystems are also explored. This work hinges current understandings of NTM, approaching their biology and heterogeneity from several angles and reinforcing the complexity of these microorganisms often associated with a multiplicity of diseases, including pulmonary, soft-tissue, or milliary. In addition to emphasizing the cornerstones of knowledge involving these bacteria, we identify research gaps that need to be addressed, stressing out the need for decision-makers to recognize NTM infection as a public health issue that has to be tackled, especially when considering an increasingly susceptible elderly and immunocompromised population in developed countries, as well as in low- or middle-income countries, where NTM infections are still highly misdiagnosed and neglected.

RevDate: 2020-09-11

Pan XX, Yuan MQ, Xiang SY, et al (2020)

The symbioses of endophytic fungi shaped the metabolic profiles in grape leaves of different varieties.

PloS one, 15(9):e0238734 pii:PONE-D-20-13785.

Endophytic fungi produce many novel bioactive metabolites that are directly used as drugs or that function as the precursor structures of other chemicals. The metabolic shaping of endophytes on grape cells was reported previously. However, there are no reports on the interactions and metabolic impact of endophyte symbiosis on in vitro vine leaves, which may be examined under well-controlled conditions that are more representative of the natural situation of endophytes within grapevines. The present study used an in vitro leaf method to establish endophyte symbiosis of grapevines and analyze the effects on the metabolic profiles of grape leaves from two different cultivars, 'Rose honey' (RH) and 'Cabernet sauvignon' (CS). The effects of endophytic fungi on the metabolic profiles of grape leaves exhibited host selectivity and fungal strain specificity. Most of the endophytic fungal strains introduced novel metabolites into the two varieties of grape leaves according to the contents of the detected metabolites and composition of metabolites. Strains RH49 and MDR36, with high or moderate symbiosis rates, triggered an increased response in terms of the detected metabolites, and the strains MDR1 and MDR33 suppressed the detected metabolites in CS and RH leaves despite having strong or moderate symbiosis ability. However, the strain RH12 significantly induced the production of novel metabolites in RH leaves due to its high symbiosis ability and suppression of metabolites in CS leaves.

RevDate: 2020-09-11

Košuthová A, Bergsten J, Westberg M, et al (2020)

Species delimitation in the cyanolichen genus Rostania.

BMC evolutionary biology, 20(1):115 pii:10.1186/s12862-020-01681-w.

BACKGROUND: In this study, we investigate species limits in the cyanobacterial lichen genus Rostania (Collemataceae, Peltigerales, Lecanoromycetes). Four molecular markers (mtSSU rDNA, β-tubulin, MCM7, RPB2) were sequenced and analysed with two coalescent-based species delimitation methods: the Generalized Mixed Yule Coalescent model (GMYC) and a Bayesian species delimitation method (BPP) using a multispecies coalescence model (MSC), the latter with or without an a priori defined guide tree.

RESULTS: Species delimitation analyses indicate the presence of eight strongly supported candidate species. Conclusive correlation between morphological/ecological characters and genetic delimitation could be found for six of these. Of the two additional candidate species, one is represented by a single sterile specimen and the other currently lacks morphological or ecological supporting evidence.

CONCLUSIONS: We conclude that Rostania includes a minimum of six species: R. ceranisca, R. multipunctata, R. occultata 1, R. occultata 2, R. occultata 3, and R. occultata 4,5,6. Three distinct Nostoc morphotypes occur in Rostania, and there is substantial correlation between these morphotypes and Rostania thallus morphology.

RevDate: 2020-09-11
CmpDate: 2020-09-11

Rush TA, Puech-Pagès V, Bascaules A, et al (2020)

Lipo-chitooligosaccharides as regulatory signals of fungal growth and development.

Nature communications, 11(1):3897.

Lipo-chitooligosaccharides (LCOs) are signaling molecules produced by rhizobial bacteria that trigger the nodulation process in legumes, and by some fungi that also establish symbiotic relationships with plants, notably the arbuscular and ecto mycorrhizal fungi. Here, we show that many other fungi also produce LCOs. We tested 59 species representing most fungal phyla, and found that 53 species produce LCOs that can be detected by functional assays and/or by mass spectroscopy. LCO treatment affects spore germination, branching of hyphae, pseudohyphal growth, and transcription in non-symbiotic fungi from the Ascomycete and Basidiomycete phyla. Our findings suggest that LCO production is common among fungi, and LCOs may function as signals regulating fungal growth and development.

RevDate: 2020-09-11
CmpDate: 2020-09-11

Koumandou VL, Papageorgiou L, Tsaniras SC, et al (2020)

Microbiome Hijacking Towards an Integrative Pest Management Pipeline.

Advances in experimental medicine and biology, 1195:21-32.

Pesticides are necessary to fight agricultural pests, yet they are often nonspecific, and their widespread use is a hazard to the environment and human health. The genomic era allows for new approaches to specifically target agricultural pests, based on analysis of their genome and their microbiome. We present such an approach, to combat Bactrocera oleae, a widespread pest whose impact is devastating on olive production. To date, there is no specific pesticide to control it. Herein, we propose a novel strategy to manage this pest via identifying novel pharmacological targets on the genome of its obligate endosymbiotic bacterium Candidatus Erwinia dacicola. Three genes were selected as pharmacological targets. The 3D models of the Helicase, Polymerase, and Protease-C gene products were designed and subsequently optimized by means of molecular dynamics simulations. Successively, a series of structure-based pharmacophore models were elucidated in an effort to pave the way for the efficient high-throughput virtual screening of libraries of low molecular weight compounds and thus the discovery of novel modulating agents. Our methodology provides the means to design, test, and identify highly specific pest control substances that minimize the impact of toxic chemicals on health, economy, and the environment.

RevDate: 2020-09-11
CmpDate: 2020-09-11

Hoysted GA, Jacob AS, Kowal J, et al (2019)

Mucoromycotina Fine Root Endophyte Fungi Form Nutritional Mutualisms with Vascular Plants.

Plant physiology, 181(2):565-577.

Fungi and plants have engaged in intimate symbioses that are globally widespread and have driven terrestrial biogeochemical processes since plant terrestrialization >500 million years ago. Recently, hitherto unknown nutritional mutualisms involving ancient lineages of fungi and nonvascular plants have been discovered, although their extent and functional significance in vascular plants remain uncertain. Here, we provide evidence of carbon-for-nitrogen exchange between an early-diverging vascular plant (Lycopodiella inundata) and Mucoromycotina (Endogonales) fine root endophyte fungi. Furthermore, we demonstrate that the same fungal symbionts colonize neighboring nonvascular and flowering plants. These findings fundamentally change our understanding of the physiology, interrelationships, and ecology of underground plant-fungal symbioses in modern terrestrial ecosystems by revealing the nutritional role of Mucoromycotina fungal symbionts in vascular plants.

RevDate: 2020-09-10

Rossbacher S, C Vorburger (2020)

Prior adaptation of parasitoids improves biological control of symbiont-protected pests.

Evolutionary applications, 13(8):1868-1876 pii:EVA12934.

There is increasing demand for sustainable pest management to reduce harmful effects of pesticides on the environment and human health. For pest aphids, biological control with parasitoid wasps provides a welcome alternative, particularly in greenhouses. However, aphids are frequently infected with the heritable bacterial endosymbiont Hamiltonella defensa, which increases resistance to parasitoids and thereby hampers biological control. Using the black bean aphid (Aphis fabae) and its main parasitoid Lysiphlebus fabarum, we tested whether prior adaptation of parasitoids can improve the control of symbiont-protected pests. We had parasitoid lines adapted to two different strains of H. defensa by experimental evolution, as well as parasitoids evolved on H. defensa-free aphids. We compared their ability to control caged aphid populations comprising 60% unprotected and 40% H. defensa-protected aphids, with both H. defensa strains present in the populations. Parasitoids that were not adapted to H. defensa had virtually no effect on aphid population dynamics compared to parasitoid-free controls, but one of the adapted lines and a mixture of both adapted lines controlled aphids successfully, strongly benefitting plant growth. Selection by parasitoids altered aphid population composition in a very specific manner. Aphid populations became dominated by H. defensa-protected aphids in the presence of parasitoids, and each adapted parasitoid line selected for the H. defensa strain it was not adapted to. This study shows, for the first time, that prior adaptation of parasitoids improves biological control of symbiont-protected pests, but the high specificity of parasitoid counter-resistance may represent a challenge for its implementation.

RevDate: 2020-09-10

Sharma A, SH Im (2020)

Special issue on the human microbiome: from symbiosis to therapy.

RevDate: 2020-09-10

Jain SS, Afiq-Rosli L, Feldman B, et al (2020)

Homogenization of Endosymbiont Communities Hosted by Equatorial Corals during the 2016 Mass Bleaching Event.

Microorganisms, 8(9): pii:microorganisms8091370.

Thermal stress drives the bleaching of reef corals, during which the endosymbiotic relationship between Symbiodiniaceae microalgae and the host breaks down. The endosymbiont communities are known to shift in response to environmental disturbances, but how they respond within and between colonies during and following bleaching events remains unclear. In 2016, a major global-scale bleaching event hit countless tropical reefs. Here, we investigate the relative abundances of Cladocopium LaJeunesse & H.J.Jeong, 2018 and Durusdinium LaJeunesse, 2018 within and among Pachyseris speciosa colonies in equatorial Singapore that are known to host both these Symbiodiniaceae clades. Bleached and unbleached tissues from bleaching colonies, as well as healthy colonies, during and following the bleaching event were sampled and analyzed for comparison. The nuclear ribosomal internal transcribed spacer (ITS) regions were separately amplified and quantified using a SYBR Green-based quantitative polymerase chain reaction (qPCR) method and Illumina high-throughput sequencing. We found Cladocopium to be highly abundant relative to Durusdinium. The relative abundance of Durusdinium, known to be thermally tolerant, was highest in post-bleaching healthy colonies, while bleached and unbleached tissues from bleaching colonies as well as tissue from healthy colonies during the event had depressed proportions of Durusdinium. Given the importance of Durusdinium for thermal tolerance and stress response, it is surprising that bleached tissue showed limited change over healthy tissue during the bleaching event. Moreover, colonies were invariably dominated by Cladocopium during bleaching, but a minority of colonies were Durusdinium-dominant during non-bleaching times. The detailed characterization of Symbiodiniaceae in specific colonies during stress and recovery will provide insights into this crucial symbiosis, with implications for their responses during major bleaching events.

RevDate: 2020-09-10
CmpDate: 2020-09-10

Lhee D, Ha JS, Kim S, et al (2019)

Evolutionary dynamics of the chromatophore genome in three photosynthetic Paulinella species.

Scientific reports, 9(1):2560.

The thecate amoeba Paulinella is a valuable model for understanding plastid organellogenesis because this lineage has independently gained plastids (termed chromatophores) of alpha-cyanobacterial provenance. Plastid primary endosymbiosis in Paulinella occurred relatively recently (90-140 million years ago, Mya), whereas the origin of the canonical Archaeplastida plastid occurred >1,500 Mya. Therefore, these two events provide independent perspectives on plastid formation on vastly different timescales. Here we generated the complete chromatophore genome sequence from P. longichromatophora (979,356 bp, GC-content = 38.8%, 915 predicted genes) and P. micropora NZ27 (977,190 bp, GC-content = 39.9%, 911 predicted genes) and compared these data to that from existing chromatophore genomes. Our analysis suggests that when a basal split occurred among photosynthetic Paulinella species ca. 60 Mya, only 35% of the ancestral orthologous gene families from the cyanobacterial endosymbiont remained in chromatophore DNA. Following major gene losses during the early stages of endosymbiosis, this process slowed down significantly, resulting in a conserved gene content across extant taxa. Chromatophore genes faced relaxed selection when compared to homologs in free-living alpha-cyanobacteria, likely reflecting the homogeneous intracellular environment of the Paulinella host. Comparison of nucleotide substitution and insertion/deletion events among different P. micropora strains demonstrates that increases in AT-content and genome reduction are ongoing and dynamic processes in chromatophore evolution.

RevDate: 2020-09-09

Mu X, Zhang S, Han B, et al (2020)

Impacts of water flow on epiphytic microbes and nutrients removal in constructed wetlands dominated by Vallisneria natans with decreasing temperature.

Bioresource technology, 318:124058 pii:S0960-8524(20)31330-4 [Epub ahead of print].

The mechanisms behind water flow on contaminant removal by a submerged macrophyte-biofilm complex in surface flow wetlands remain to be fully elucidated. In this study, water flow (2.02 ~ 2.12 or 4.06 ~ 4.5 L s-1; hydraulic retention time, 7d) significantly enhanced NH4+-N and COD but inhibited TN and TP removal compared to the static ones. No more than 30% of TN and TP were assimilated by V. natans-biofilm complex in wetland system. Water flow remarkably affected alpha-diversity of microbial community in epiphytic biofilm. As revealed by beta-diversity analysis, turnover played greater contribution to the total dissimilarity than nestedness. Network analyses revealed that the microbial interactions including predation, symbiosis and competition in epiphytic biofilms were much more intensive in the Sept.- Oct. than the Nov.-Dec group. Redundancy and Mantel correlation analyses revealed that temperature played a key role in determining microbial community structure, especially for bacteria.

RevDate: 2020-09-09

Singh A, Jadhav S, MR Roopashree (2020)

Factors to Overcoming Barriers Affecting Electronic Medical Record Usage by Physicians.

Indian journal of community medicine : official publication of Indian Association of Preventive & Social Medicine, 45(2):168-171.

Background: Hospitals are adopting electronic medical records (EMRs) in larger numbers; however, the barrier to derive its full utility is the low acceptance by physicians.

Aims and Objectives: This study is done with an objective to identify the factors to overcome the barriers preventing the adoption of EMR by physicians.

Materials and Methods: This study is cross sectional in natures and a self-administered questionnaire is developed based on the Technology Acceptance Model.

Results: The four identified factors are positive attitude toward EMR, reliability, difficulty to use, and adaptability, these factors together, have explained 62.54 percent variance in the data set.

Conclusion: The physician's acceptance for EMRs can be improved by focusing on the identified four factors, which are "positive attitude toward electronic medical records," reliability of electronic medical records," "difficulty level of use," and "adaptability of electronic medical records."

RevDate: 2020-09-09

Ding PH, Yang MX, Wang NN, et al (2020)

Porphyromonas gingivalis-Induced NLRP3 Inflammasome Activation and Its Downstream Interleukin-1β Release Depend on Caspase-4.

Frontiers in microbiology, 11:1881.

Background: Oral commensals contribute to microbe-host symbiosis in periodontal homeostasis, and Porphyromonas gingivalis (P. gingivalis) as the keystone pathogen critically accounts for the shift of symbiosis to dysbiosis and periodontal destruction. Nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome-mediated interleukin-1β (IL-1β) is significantly involved in periodontal diseases, and notably P. gingivalis enables to modulate the induction and expression of NLRP3. Whereas, the exact mechanism by which NLRP3 inflammasome is regulated in response to commensal and pathogenic bacteria remains unclear. Methods: To examine the expression of IL-1β and NLRPs inflammasome in tissues with severe chronic periodontitis, and further investigate how Caspase-4-dependent non-canonical NLRP3 inflammasome pathways functioned during the interactions of Streptococcus mitis (S. mitis) and P. gingivalis with human THP-1 cells. Results: IL-1β and NLRP3, NLRP6, NLRP12, and absent in melanoma 2 (AIM2) inflammasomes are highly expressed in gingival tissues with severe chronic periodontitis. In human THP-1 cells, P. gingivalis activates the synthesis and secretion of IL-1β to higher levels than S. mitis. Importantly, NLRP3-, Caspase-1-, and Caspase-4-siRNA knockdown THP-1 cells treated with P. gingivalis exhibited a lower expression level of IL-1β as compared to the control cells. In addition, silencing of either CASP4 or CASP1 can lead to a concurrent or reciprocal decrease in the expression of the other. Of note, the IL-1β induction is not affected in the S. mitis-treated THP-1 cells with the silence of NLRP3, Caspase-1, and Caspase-4 genes. Conclusion: NLRP3/Caspase-4 and NLRP3/Caspase-1 dependent IL-1β production may crucially contribute to the dysregulated immuno-inflammatory response in periodontal pathogenesis.

RevDate: 2020-09-09

Wheatley RM, Ford BL, Li L, et al (2020)

Lifestyle adaptations of Rhizobium from rhizosphere to symbiosis.

Proceedings of the National Academy of Sciences of the United States of America pii:2009094117 [Epub ahead of print].

By analyzing successive lifestyle stages of a model Rhizobium-legume symbiosis using mariner-based transposon insertion sequencing (INSeq), we have defined the genes required for rhizosphere growth, root colonization, bacterial infection, N2-fixing bacteroids, and release from legume (pea) nodules. While only 27 genes are annotated as nif and fix in Rhizobium leguminosarum, we show 603 genetic regions (593 genes, 5 transfer RNAs, and 5 RNA features) are required for the competitive ability to nodulate pea and fix N2 Of these, 146 are common to rhizosphere growth through to bacteroids. This large number of genes, defined as rhizosphere-progressive, highlights how critical successful competition in the rhizosphere is to subsequent infection and nodulation. As expected, there is also a large group (211) specific for nodule bacteria and bacteroid function. Nodule infection and bacteroid formation require genes for motility, cell envelope restructuring, nodulation signaling, N2 fixation, and metabolic adaptation. Metabolic adaptation includes urea, erythritol and aldehyde metabolism, glycogen synthesis, dicarboxylate metabolism, and glutamine synthesis (GlnII). There are 17 separate lifestyle adaptations specific to rhizosphere growth and 23 to root colonization, distinct from infection and nodule formation. These results dramatically highlight the importance of competition at multiple stages of a Rhizobium-legume symbiosis.

RevDate: 2020-09-09

Hamada M, Satoh N, K Khalturin (2020)

A Reference Genome from the Symbiotic Hydrozoan, Hydra viridissima.

G3 (Bethesda, Md.) pii:g3.120.401411 [Epub ahead of print].

Various Hydra species have been employed as model organisms since the 18th century. Introduction of transgenic and knock-down technologies made them ideal experimental systems for studying cellular and molecular mechanisms involved in regeneration, body-axis formation, senescence, symbiosis, and holobiosis. In order to provide an important reference for genetic studies, the Hydra magnipapillata genome (species name has been changed to H. vulgaris) was sequenced a decade ago (Chapman et al, 2010) and the updated genome assembly, Hydra 2.0, was made available by the National Human Genome Research Institute in 2017. While H. vulgaris belongs to the non-symbiotic brown hydra lineage, the green hydra, Hydra viridissima, harbors algal symbionts and belongs to an early diverging clade that separated from the common ancestor of brown and green hydra lineages at least 100 million years ago (Schwentner and Bosch, 2015; Khalturin et al, 2019). While interspecific interactions between H. viridissima and endosymbiotic unicellular green algae of the genus Chlorella have been a subject of interest for decades, genomic information about green hydras was nonexistent. Here we report a draft 280-Mbp genome assembly for Hydra viridissima strain A99, with a scaffold N50 of 1.1 Mbp. The H. viridissima genome contains an estimated 21,476 protein-coding genes. Comparative analysis of Pfam domains and orthologous proteins highlights characteristic features of H. viridissima, such as diversification of innate immunity genes that are important for host-symbiont interactions. Thus, the H. viridissima assembly provides an important hydrozoan genome reference that will facilitate symbiosis research and better comparisons of metazoan genome architectures.

RevDate: 2020-09-09

Lastovetsky OA, Krasnovsky LD, Qin X, et al (2020)

Molecular Dialogues between Early Divergent Fungi and Bacteria in an Antagonism versus a Mutualism.

mBio, 11(5): pii:mBio.02088-20.

Fungal-bacterial symbioses range from antagonisms to mutualisms and remain one of the least understood interdomain interactions despite their ubiquity as well as ecological and medical importance. To build a predictive conceptual framework for understanding interactions between fungi and bacteria in different types of symbioses, we surveyed fungal and bacterial transcriptional responses in the mutualism between Rhizopus microsporus (Rm) (ATCC 52813, host) and its Mycetohabitans (formerly Burkholderia) endobacteria versus the antagonism between a nonhost Rm (ATCC 11559) and Mycetohabitans isolated from the host, at two time points, before and after partner physical contact. We found that bacteria and fungi sensed each other before contact and altered gene expression patterns accordingly. Mycetohabitans did not discriminate between the host and nonhost and engaged a common set of genes encoding known as well as novel symbiosis factors. In contrast, responses of the host versus nonhost to endobacteria were dramatically different, converging on the altered expression of genes involved in cell wall biosynthesis and reactive oxygen species (ROS) metabolism. On the basis of the observed patterns, we formulated a set of hypotheses describing fungal-bacterial interactions and tested some of them. By conducting ROS measurements, we confirmed that nonhost fungi increased production of ROS in response to endobacteria, whereas host fungi quenched their ROS output, suggesting that ROS metabolism contributes to the nonhost resistance to bacterial infection and the host ability to form a mutualism. Overall, our study offers a testable framework of predictions describing interactions of early divergent Mucoromycotina fungi with bacteria.IMPORTANCE Animals and plants interact with microbes by engaging specific surveillance systems, regulatory networks, and response modules that allow for accommodation of mutualists and defense against antagonists. Antimicrobial defense responses are mediated in both animals and plants by innate immunity systems that owe their functional similarities to convergent evolution. Like animals and plants, fungi interact with bacteria. However, the principles governing these relations are only now being discovered. In a study system of host and nonhost fungi interacting with a bacterium isolated from the host, we found that bacteria used a common gene repertoire to engage both partners. In contrast, fungal responses to bacteria differed dramatically between the host and nonhost. These findings suggest that as in animals and plants, the genetic makeup of the fungus determines whether bacterial partners are perceived as mutualists or antagonists and what specific regulatory networks and response modules are initiated during each encounter.

RevDate: 2020-09-09

Formiga F, FJ Tarazona-Santabalbina (2020)

[Diabetes and COVID-19 in the elderly, harmful symbiosis].

Revista espanola de geriatria y gerontologia pii:S0211-139X(20)30134-7 [Epub ahead of print].

RevDate: 2020-09-09

Scherlach K, C Hertweck (2020)

Chemical Mediators at the Bacterial-Fungal Interface.

Annual review of microbiology, 74:267-290.

Interactions among microbes are key drivers of evolutionary progress and constantly shape ecological niches. Microorganisms rely on chemical communication to interact with each other and surrounding organisms. They synthesize natural products as signaling molecules, antibiotics, or modulators of cellular processes that may be applied in agriculture and medicine. Whereas major insight has been gained into the principles of intraspecies interaction, much less is known about the molecular basis of interspecies interplay. In this review, we summarize recent progress in the understanding of chemically mediated bacterial-fungal interrelations. We discuss pairwise interactions among defined species and systems involving additional organisms as well as complex interactions among microbial communities encountered in the soil or defined as microbiota of higher organisms. Finally, we give examples of how the growing understanding of microbial interactions has contributed to drug discovery and hypothesize what may be future directions in studying and engineering microbiota for agricultural or medicinal purposes.

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

Kirchhoff T (2020)

The myth of Frederic Clements's mutualistic organicism, or: on the necessity to distinguish different concepts of organicism.

History and philosophy of the life sciences, 42(2):24 pii:10.1007/s40656-020-00317-y.

In the theory and history of ecology, Frederic Clements's theory of plant communities is usually presented as the historical prototype and a paradigmatic example of synecological organicism, characterised by the assumption that ecological communities are functionally integrated units of mutually dependent species. In this paper, I will object to this standard interpretation of Clements's theory. Undoubtedly, Clements compares plant communities with organisms and calls them "complex organisms" and "superorganisms". Further, he can indeed be regarded as a proponent of ecological organicism-provided that one defines ecological organicism as the interpretation of synecological units according to the model of the individual organism. However, Clements's theory does not include the assumption that mutual dependence is a principle of the organisation of plant communities. Rather, he interprets plant communities as top-down control-hierarchical entities, in which subordinate species depend on dominant species-but not the other way around. Therefore, his theory represents what may be called 'control-hierarchical organicism' as against 'mutualistic organicism'. The erroneous attribution to Clements of 'mutualistic organicism' might be due to an unawareness of the existence of different concepts of the organism. This unawareness results in the projection on Clements's theory of a seemingly self-evident mutualistic concept of organism that Clements himself did not use as a basis for his theory of plant communities.

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

Schaming TD, CS Sutherland (2020)

Landscape- and local-scale habitat influences on occurrence and detection probability of Clark's nutcrackers: Implications for conservation.

PloS one, 15(5):e0233726.

Whitebark pine (Pinus albicaulis), a keystone species and an obligate mutualist of the Clark's nutcracker (Nucifraga columbiana), is rapidly declining throughout its range. Evidence suggests this decline is leading to a downward trend in local nutcracker populations, which would in-turn decrease whitebark pine regeneration. Our objectives were to (1) evaluate temporal variation in nutcracker habitat use as a function of whitebark pine and Douglas-fir (Pseudotsuga menziesii) habitat, at local and landscape scales, (2) develop metrics for predicting when whitebark pine communities require intervention to sustain nutcracker visitation, and (3) test McKinney et al. (2009) and Barringer et al.'s (2012) models predicting nutcracker occurrence. Between 2009 and 2013, we carried out 3,135 audio-visual Clark's nutcracker surveys at 238 random points in the southern Greater Yellowstone Ecosystem. Using Bayesian occupancy models and cross-product model selection, we evaluated the association between nutcracker occurrence and habitat variables during five stages of the nutcracker annual cycle, while accounting for imperfect detection. Nutcracker occurrence was most strongly associated with the presence of cone-bearing whitebark pine trees (rather than cone density) and the area of whitebark pine on the landscape. To promote a high, >75%, probability of occurrence at a site within the study area, we recommend a management plan that achieves a landscape composed of a minimum of 12,500-25,000 ha of cone-bearing whitebark pine habitat within a 32.6 km radius. Additionally, an optimal habitat mosaic includes moderate levels of Douglas-fir habitat. Models currently used to guide whitebark pine management strategies underpredicted nutcracker occurrence in our study area, suggesting these strategies may not be appropriate in the region. We cannot predict how this mutualistic relationship will change as the population density of each species shifts. We therefore suggest conducting periodic surveys to re-evaluate the relationship as the environment changes and management strategies are implemented.

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

Ganyukova AI, Frolov AO, Malysheva MN, et al (2020)

A novel endosymbiont-containing trypanosomatid Phytomonas borealis sp. n. from the predatory bug Picromerus bidens (Heteroptera: Pentatomidae).

Folia parasitologica, 67:.

Here we describe the new trypanosomatid, Phytomonas borealis sp. n., from the midgut of the spiked shieldbugs, Picromerus bidens (Linnaeus), collected in two locations, Novgorod and Pskov Oblasts of Russia. The phylogenetic analyses, based on the 18S rRNA gene, demonstrated that this flagellate is a sister species to the secondary monoxenous Phytomonas nordicus Frolov et Malysheva, 1993, which was concurrently documented in the same host species in Pskov Oblast. Unlike P. nordicus, which can complete its development (including exit to haemolymph and penetration into salivary glands) in Picromerus bidens, the new species did not form any extraintestinal stages in the host. It also did not produce endomastigotes, indispensable for transmission in other Phytomonas spp. These observations, along with the fact that P. bidens overwinters at the egg stage, led us to the conclusion that the examined infections with P. borealis were non-specific. Strikingly, the flagellates from the Novgorod population contained prokaryotic endosymbionts, whereas the parasites from the second locality were endosymbiont-free. This is a first case documenting presence of intracellular symbiotic bacteria in Phytomonas spp. We suggest that this novel endosymbiotic association arose very recently and did not become obligate yet. Further investigation of P. borealis and its intracellular bacteria may shed light on the origin and early evolution of endosymbiosis in trypanosomatids.

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

Pandit A, Adholeya A, Cahill D, et al (2020)

Microbial biofilms in nature: unlocking their potential for agricultural applications.

Journal of applied microbiology, 129(2):199-211.

Soil environments are dynamic and the plant rhizosphere harbours a phenomenal diversity of micro-organisms which exchange signals and beneficial nutrients. Bipartite beneficial or symbiotic interactions with host roots, such as mycorrhizae and various bacteria, are relatively well characterized. In addition, a tripartite interaction also exists between plant roots, arbuscular mycorrhizal fungi (AMF) and associated bacteria. Bacterial biofilms exist as a sheet of bacterial cells in association with AMF structures, embedded within a self-produced exopolysaccharide matrix. Such biofilms may play important functional roles within these tripartite interactions. However, the details about such interactions in the rhizosphere and their relevant functional relationships have not been elucidated. This review explores the current understanding of naturally occurring microbial biofilms, and their interaction with biotic surfaces, especially AMF. The possible roles played by bacterial biofilms and the potential for their application for a more productive and sustainable agriculture is discussed in this review.

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

Nag P, Shriti S, S Das (2020)

Microbiological strategies for enhancing biological nitrogen fixation in nonlegumes.

Journal of applied microbiology, 129(2):186-198.

In an agro-ecosystem, industrially produced nitrogenous fertilizers are the principal sources of nitrogen for plant growth; unfortunately these also serve as the leading sources of pollution. Hence, it becomes imperative to find pollution-free methods of providing nitrogen to crop plants. A diverse group of free-living, plant associative and symbiotic prokaryotes are able to perform biological nitrogen fixation (BNF). BNF is a two component process involving the nitrogen fixing diazotrophs and the host plant. Symbiotic nitrogen fixation is most efficient as it can fix nitrogen inside the nodule formed on the roots of the plant; delivering nitrogen directly to the host. However, most of the important crop plants are nonleguminous and are unable to form symbiotic associations. In this context, the plant associative and endophytic diazotrophs assume importance. BNF in nonlegumes can be encouraged either through the transfer of BNF traits from legumes or by elevating the nitrogen fixing capacity of the associative and endophytic diazotrophs. In this review we discuss mainly the microbiological strategies which may be used in nonleguminous crops for enhancement of BNF.

RevDate: 2020-09-08

Rejili M, Off K, Brachmann A, et al (2020)

Bradyrhizobium hipponense sp. nov., isolated from Lupinus angustifolius growing in the northern region of Tunisia.

International journal of systematic and evolutionary microbiology [Epub ahead of print].

Strain aSej3T was isolated from a root nodule of a Lupinus angustifolius plant growing in Bizerte, Tunisia. 16S rRNA gene analysis placed this strain within the genus Bradyrhizobium. Multilocus sequence analysis (MLSA) including three housekeeping genes (glnII, gyrB and recA) grouped aSej3T together with Bradyrhizobium rifense CTAW71T, Bradyrhizobium cytisi CTAW11T, Bradyrhizobium ganzhouense RITF806T, Bradyrhizobium lupini USDA 3051T and Bradyrhizobium canariense BTA-1T. MLSA with five housekeeping genes (dnaK, glnII, gyrB, recA and rpoB) revealed that this strain shares less than 93.5 % nucleotide identity with other type strains. Genome sequencing and inspection revealed a genome size of 8.83 Mbp with a G+C content of 62.8 mol%. Genome-wide average nucleotide identity and digital DNA-DNA hybridization values were below 87.5 and 36.2 %, respectively, when compared to described Bradyrhizobium species. Strain aSej3T nodulated L. angustifolius plants under axenic conditions and its nodC gene clustered within the genistearum symbiovar. Altogether, the phylogenetic data and the chemotaxonomic characteristics of this strain support that aSej3T represents a new species for which we propose the name Bradyrhizobium hipponense sp. nov. with the type strain aSej3T (=DSM 108913T=LMG 31020T).

RevDate: 2020-09-08

Koch RA, Liu J, Brann M, et al (2020)

Marasmioid rhizomorphs in bird nests: Species diversity, functional specificity, and new species from the tropics.

Mycologia [Epub ahead of print].

In tropical and subtropical rainforests, vegetative fungal rhizomorphs from the Marasmiineae are routinely used as construction material in bird nests. Because rhizomorphs seldom produce mushrooms within nests, the fungal species involved remain largely unknown. In turn, this limitation has prevented us from resolving broader questions such as whether specific fungal species are selected by birds for different functional roles (i.e., attachment, or parasite control). To fill some of these gaps, we collected 74 rhizomorph-containing bird nests from the Neo- and Afrotropics and used nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) sequences to discriminate between rhizomorph-forming species. In total we recovered 25 Marasmiineae species used by birds in nest construction, none of which were shared between the Neotropics and the Afrotropics. We also collected Marasmiineae basidiomes in the vicinity of nests and used ITS sequences to match these sporulating morphs with nest rhizomorphs for nine species. Basidiomes from an additional five species were found fruiting from rhizomorphs incorporated within bird nests. Finally, an additional six species were putatively identified based on publicly available sequence data. Rhizomorphs of five species were found to be utilized almost exclusively as lining material in nests. Lining material comes in direct contact with nestlings and is hypothesized to play a role in parasite control. Rhizomorphs from 10 species were used to attach and anchor nests to substrates; we matched six of those to fruiting litter trap-forming species collected in the understory. Litter traps hold large quantities of fallen litter material, suggesting that birds may preferentially use rhizomorphs that are adapted to bearing heavy loads for nest attachment. Finally, we describe two species of Marasmius-M. neocrinis-equi, sp. nov., and M. nidus-avis, sp. nov.-that are commonly found associated with bird nests and show that rhizomorph production is common across the genus.

RevDate: 2020-09-08
CmpDate: 2020-09-08

Ianiri G, Coelho MA, Ruchti F, et al (2020)

HGT in the human and skin commensal Malassezia: A bacterially derived flavohemoglobin is required for NO resistance and host interaction.

Proceedings of the National Academy of Sciences of the United States of America, 117(27):15884-15894.

The skin of humans and animals is colonized by commensal and pathogenic fungi and bacteria that share this ecological niche and have established microbial interactions. Malassezia are the most abundant fungal skin inhabitant of warm-blooded animals and have been implicated in skin diseases and systemic disorders, including Crohn's disease and pancreatic cancer. Flavohemoglobin is a key enzyme involved in microbial nitrosative stress resistance and nitric oxide degradation. Comparative genomics and phylogenetic analyses within the Malassezia genus revealed that flavohemoglobin-encoding genes were acquired through independent horizontal gene transfer events from different donor bacteria that are part of the mammalian microbiome. Through targeted gene deletion and functional complementation in Malassezia sympodialis, we demonstrated that bacterially derived flavohemoglobins are cytoplasmic proteins required for nitric oxide detoxification and nitrosative stress resistance under aerobic conditions. RNA-sequencing analysis revealed that endogenous accumulation of nitric oxide resulted in up-regulation of genes involved in stress response and down-regulation of the MalaS7 allergen-encoding genes. Solution of the high-resolution X-ray crystal structure of Malassezia flavohemoglobin revealed features conserved with both bacterial and fungal flavohemoglobins. In vivo pathogenesis is independent of Malassezia flavohemoglobin. Lastly, we identified an additional 30 genus- and species-specific horizontal gene transfer candidates that might have contributed to the evolution of this genus as the most common inhabitants of animal skin.

RevDate: 2020-09-08
CmpDate: 2020-09-08

Velivelli SLS, Czymmek KJ, Li H, et al (2020)

Antifungal symbiotic peptide NCR044 exhibits unique structure and multifaceted mechanisms of action that confer plant protection.

Proceedings of the National Academy of Sciences of the United States of America, 117(27):16043-16054.

In the indeterminate nodules of a model legume Medicago truncatula, ∼700 nodule-specific cysteine-rich (NCR) peptides with conserved cysteine signature are expressed. NCR peptides are highly diverse in sequence, and some of these cationic peptides exhibit antimicrobial activity in vitro and in vivo. However, there is a lack of knowledge regarding their structural architecture, antifungal activity, and modes of action against plant fungal pathogens. Here, the three-dimensional NMR structure of the 36-amino acid NCR044 peptide was solved. This unique structure was largely disordered and highly dynamic with one four-residue α-helix and one three-residue antiparallel β-sheet stabilized by two disulfide bonds. NCR044 peptide also exhibited potent fungicidal activity against multiple plant fungal pathogens, including Botrytis cinerea and three Fusarium spp. It inhibited germination in quiescent spores of B. cinerea In germlings, it breached the fungal plasma membrane and induced reactive oxygen species. It bound to multiple bioactive phosphoinositides in vitro. Time-lapse confocal and superresolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, subsequent accumulation in the cytoplasm, and elevated levels in nucleoli of germlings. Spray-applied NCR044 significantly reduced gray mold disease symptoms caused by the fungal pathogen B. cinerea in tomato and tobacco plants, and postharvest products. Our work illustrates the antifungal activity of a structurally unique NCR peptide against plant fungal pathogens and paves the way for future development of this class of peptides as a spray-on fungistat/fungicide.

RevDate: 2020-09-08
CmpDate: 2020-09-08

Silva R, Filgueiras L, Santos B, et al (2020)

Gluconacetobacter diazotrophicus Changes The Molecular Mechanisms of Root Development in Oryza sativa L. Growing Under Water Stress.

International journal of molecular sciences, 21(1):.

BACKGROUND: Inoculation with Gluconacetobacter diazotrophicus has shown to influence root development in red rice plants, and more recently, the induced systemic tolerance (IST) response to drought was also demonstrated. The goal of this study was to evaluate the inoculation effect of G. diazotrophicus strain Pal5 on the amelioration of drought stress and root development in red rice (Oryza sativa L.).

METHODS: The experimental treatments consist of red rice plants inoculated with and without strain Pal5 in presence and absence of water restriction. Physiological, biochemical, and molecular analyses of plant roots were carried out, along with measurements of growth and biochemical components.

RESULTS: The plants showed a positive response to the bacterial inoculation, with root growth promotion and induction of tolerance to drought. An increase in the root area and higher levels of osmoprotectant solutes were observed in roots. Bacterial inoculation increased the drought tolerance and positively regulated certain root development genes against the water deficit in plants.

CONCLUSION: G. diazotrophicus Pal5 strain inoculation favored red rice plants by promoting various root growth and developmental mechanisms against drought stress, enabling root development and improving biochemical composition.

RevDate: 2020-09-08
CmpDate: 2020-09-08

Strand MR, GR Burke (2020)

Polydnaviruses: Evolution and Function.

Current issues in molecular biology, 34:163-182.

Polydnaviruses (PDVs) were originally viewed as large DNA viruses that are beneficial symbionts of parasitoid wasps. Two groups of PDVs were also recognized: bracoviruses (BVs), which are associated with wasps in the family Braconidae, and ichnoviruses (IVs), which are associated with wasps in the family Ichneumonidae. Results to date indicate that BVs are endogenous virus elements (EVEs) that evolved from an ancient betanudivirus. IVs are also likely EVEs but are unrelated to BVs. BVs and IVs are very unusual relative to most known EVEs because they retain many viral functions that benefit wasps in parasitizing hosts. However, BVs and IVs cannot be considered beneficial symbionts because all components of their genomes are fixed in wasps. Recent studies indicate that other nudiviruses have endogenized in insects. Each exhibits a different functional fate from BVs but shares certain architectural features. We discuss options for classifying BVs and other endogenized nudiviruses. We also discuss future directions.

RevDate: 2020-09-07

Lenhart PA, JA White (2020)

Endosymbionts facilitate rapid evolution in a polyphagous herbivore.

Journal of evolutionary biology [Epub ahead of print].

Maternally transmitted bacterial symbionts can be important mediators of the interactions between insect herbivores and their foodplants. These symbionts are often facultative (present in some host individuals but not others) and can have large effects on their host's phenotype, thus giving rise to heritable variation upon which selection can act. In the cowpea aphid (Aphis craccivora) it has been established that the facultative endosymbiont Arsenophonus improves aphid performance on black locust trees (Robinia pseudoacacia) but not on fava (Vicia faba). Here, we tested whether this fitness differential translated into contemporaneous evolution of aphid populations associated with the different plants. In a laboratory study lasting 16 weeks, we found that the frequency of Arsenophonus-infected individuals significantly increased over time for aphid populations on black locust but declined for aphid populations on fava. By the end of the experiment, Arsenophonus infection was >3× more common on black locust than fava, which is comparable to previously described infection frequencies in natural field populations. Our results clearly demonstrate that aphid populations with mixed facultative symbiont infection status can rapidly evolve in response to the selective environments imposed by different host plants. This selection differential may be a sufficient explanation for the global association between Arsenophonus-infected cowpea aphids and black locust trees, without invoking additional assortative mechanisms. Because the aphid and plant originate from different parts of the world, we further hypothesize that Arsenophonus infection may have acted as a preadaptation that has promoted functional specialisation of infected aphids on a novel host plant.

RevDate: 2020-09-07

Shu H, Luo Z, Peng Z, et al (2020)

The application of CRISPR/Cas9 in hairy roots to explore the functions of AhNFR1 and AhNFR5 genes during peanut nodulation.

BMC plant biology, 20(1):417 pii:10.1186/s12870-020-02614-x.

BACKGROUND: Peanut is an important legume crop growing worldwide. With the published allotetraploid genomes, further functional studies of the genes in peanut are very critical for crop improvement. CRISPR/Cas9 system is emerging as a robust tool for gene functional study and crop improvement, which haven't been extensively utilized in peanut yet. Peanut plant forms root nodules to fix nitrogen through a symbiotic relationship with rhizobia. In model legumes, the response of plants to rhizobia is initiated by Nod factor receptors (NFRs). However, information about the function of NFRs in peanut is still limited. In this study, we applied the CRISPR/Cas9 tool in peanut hairy root transformation system to explore the function of NFR genes.

RESULTS: We firstly identified four AhNFR1 genes and two AhNFR5 genes in cultivated peanut (Tifrunner). The gene expression analysis showed that the two AhNFR1 and two AhNFR5 genes had high expression levels in nodulating (Nod+) line E5 compared with non-nodulating (Nod-) line E4 during the process of nodule formation, suggesting their roles in peanut nodulation. To further explore their functions in peanut nodulation, we applied CRISPR technology to create knock-out mutants of AhNFR1 and AhNFR5 genes using hairy root transformation system. The sequencing of these genes in transgenic hairy roots showed that the selected AhNFR1 and AhNFR5 genes were successfully edited by the CRISPR system, demonstrating its efficacy for targeted mutation in allotetraploid peanut. The mutants with editing in the two AhNFR5 genes showed Nod- phenotype, whereas mutants with editing in the two selected AhNFR1 genes could still form nodules after rhizobia inoculation.

CONCLUSIONS: This study showed that CRISPR-Cas9 could be used in peanut hairy root transformation system for peanut functional genomic studies, specifically on the gene function in roots. By using CRISPR-Cas9 targeting peanut AhNFR genes in hairy root transformation system, we validated the function of AhNFR5 genes in nodule formation in peanut.

RevDate: 2020-09-07
CmpDate: 2020-09-07

Geesink P, Wegner CE, Probst AJ, et al (2020)

Genome-inferred spatio-temporal resolution of an uncultivated Roizmanbacterium reveals its ecological preferences in groundwater.

Environmental microbiology, 22(2):726-737.

Subsurface ecosystems like groundwater harbour diverse microbial communities, including small-sized, putatively symbiotic organisms of the Candidate Phyla Radiation, yet little is known about their ecological preferences and potential microbial partners. Here, we investigated a member of the superphylum Microgenomates (Cand. Roizmanbacterium ADI133) from oligotrophic groundwater using mini-metagenomics and monitored its spatio-temporal distribution using 16S rRNA gene analyses. A Roizmanbacteria-specific quantitative PCR assay allowed us to track its abundance over the course of 1 year within eight groundwater wells along a 5.4 km hillslope transect, where Roizmanbacteria reached maximum relative abundances of 2.3%. In-depth genomic analyses suggested that Cand. Roizmanbacterium ADI133 is a lactic acid fermenter, potentially able to utilize a range of complex carbon substrates, including cellulose. We hypothesize that it attaches to host cells using a trimeric autotransporter adhesin and inhibits their cell wall biosynthesis using a toxin-antitoxin system. Network analyses based on correlating Cand. Roizmanbacterium ADI133 abundances with amplicon sequencing-derived microbial community profiles suggested one potential host organism, classified as a member of the class Thermodesulfovibrionia (Nitrospirae). By providing lactate as an electron donor Cand. Roizmanbacterium ADI133 potentially mediates the transfer of carbon to other microorganisms and thereby is an important connector in the microbial community.

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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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