Academic literature on the topic 'Bacterial symbiont'
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Journal articles on the topic "Bacterial symbiont"
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Murti, Damar Bayu, A. B. Susanto, Ocky Karna Radjasa, and Ferdy Semuel Rondonuwu. "Pigments Characterization and Molecular Identification of Bacterial Symbionts of Brown Algae Padinasp. Collected from Karimunjawa Island." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 21, no. 2 (June 1, 2016): 58. http://dx.doi.org/10.14710/ik.ijms.21.2.58-64.
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The search for carotenoids in nature has been extensively studied because of their applications in foods. One treasure of the biopigment source is symbiotic-microorganisms with marine biota. The advantages of symbiont bacteria are easy to culture and sensitize pigments. The use of symbiont bacteria helps to conserve fish, coral reefs, seagrass, and seaweed. Therefore, the bacteria keeps their existence in their ecosystems. In this study, bacterial symbionts were successfully isolated from brown algae Padina sp. The bacterial symbionts had yellow pigment associated with carotenoids. The pigments were characterized using High Performance Liquid Chromatography (HPLC) with a Photo Diode Array (PDA) detector. The carotenoid pigments in the bacterial symbionts were identified as dinoxanthin, lutein and neoxanthin. Molecular identification by using a 16S rRNA gene sequence method, reveals that the bacterial symbionts were closely related to Bacillus marisflavi with a homology of 99%. Keywords :carotenoid pigments, brown algae, Padina, bacterial symbionts, 16S rRNA
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Sipe, Alison R., Ami E. Wilbur, and S. Craig Cary. "Bacterial Symbiont Transmission in the Wood-Boring Shipworm Bankia setacea (Bivalvia: Teredinidae)." Applied and Environmental Microbiology 66, no. 4 (April 1, 2000): 1685–91. http://dx.doi.org/10.1128/aem.66.4.1685-1691.2000.
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ABSTRACT The Teredinidae (shipworms) are a morphologically diverse group of marine wood-boring bivalves that are responsible each year for millions of dollars of damage to wooden structures in estuarine and marine habitats worldwide. They exist in a symbiosis with cellulolytic nitrogen-fixing bacteria that provide the host with the necessary enzymes for survival on a diet of wood cellulose. These symbiotic bacteria reside in distinct structures lining the interlamellar junctions of the gill. This study investigated the mode by which these nutritionally essential bacterial symbionts are acquired in the teredinid Bankia setacea. Through 16S ribosomal DNA (rDNA) sequencing, the symbiont residing within the B. setaceagill was phylogenetically characterized and shown to be distinct from previously described shipworm symbionts. In situ hybridization using symbiont-specific 16S rRNA-directed probes bound to bacterial ribosome targets located within the host gill coincident with the known location of the gill symbionts. These specific probes were then used as primers in a PCR-based assay which consistently detected bacterial rDNA in host gill (symbiont containing), gonad tissue, and recently spawned eggs, demonstrating the presence of symbiont cells in host ovary and offspring. These results suggest that B. setacea ensures successful inoculation of offspring through a vertical mode of symbiont transmission and thereby enables a broad distribution of larval settlement.
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Matsuura, Yu, Takahiro Hosokawa, Mario Serracin, Genet M. Tulgetske, Thomas A. Miller, and Takema Fukatsu. "Bacterial Symbionts of a Devastating Coffee Plant Pest, the Stinkbug Antestiopsis thunbergii (Hemiptera: Pentatomidae)." Applied and Environmental Microbiology 80, no. 12 (April 11, 2014): 3769–75. http://dx.doi.org/10.1128/aem.00554-14.
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ABSTRACTStinkbugs of the genusAntestiopsis, so-called antestia bugs or variegated coffee bugs, are notorious pests of coffee plants in Africa. We investigated the symbiotic bacteria associated withAntestiopsis thunbergii, a major coffee plant pest in Rwanda. PCR, cloning, sequencing, and phylogenetic analysis of bacterial genes identified four distinct bacterial lineages associated withA. thunbergii: a gammaproteobacterial gut symbiont and symbionts representing the generaSodalis,Spiroplasma, andRickettsia.In situhybridization showed that the gut symbiont densely occupied the lumen of midgut crypts, whereas theSodalissymbiont, theSpiroplasmasymbiont, and theRickettsiasymbiont sparsely and sporadically infected various cells and tissues. Diagnostic PCR survey of 154A. thunbergiiindividuals collected at 8 localities in Rwanda revealed high infection frequencies (100% for the gut symbiont, 51.3% for theSodalissymbiont, 52.6% for theSpiroplasmasymbiont, and 24.0% for theRickettsiasymbiont). These results suggest that the gut symbiont is the primary symbiotic associate of obligate nature forA. thunbergii, whereas theSodalissymbiont, theSpiroplasmasymbiont, and theRickettsiasymbiont are the secondary symbiotic associates of facultative nature. We observed high coinfection frequencies, i.e., 7.8% of individuals with quadruple infection with all the symbionts, 32.5% with triple infections with the gut symbiont and two of the secondary symbionts, and 39.6% with double infections with the gut symbiont and any of the three secondary symbionts, which were statistically not different from the expected coinfection frequencies and probably reflected random associations. The knowledge of symbiotic microbiota inA. thunbergiiwill provide useful background information for controlling this devastating coffee plant pest.
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Xu, Ting-Ting, Li-Yun Jiang, Jing Chen, and Ge-Xia Qiao. "Host Plants Influence the Symbiont Diversity of Eriosomatinae (Hemiptera: Aphididae)." Insects 11, no. 4 (April 1, 2020): 217. http://dx.doi.org/10.3390/insects11040217.
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Eriosomatinae is a particular aphid group with typically heteroecious holocyclic life cycle, exhibiting strong primary host plant specialization and inducing galls on primary host plants. Aphids are frequently associated with bacterial symbionts, which can play fundamental roles in the ecology and evolution of their host aphids. However, the bacterial communities in Eriosomatinae are poorly known. In the present study, using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we surveyed the bacterial flora of eriosomatines and explored the associations between symbiont diversity and aphid relatedness, aphid host plant and geographical distribution. The microbiota of Eriosomatinae is dominated by the heritable primary endosymbiont Buchnera and several facultative symbionts. The primary endosymbiont Buchnera is expectedly the most abundant symbiont across all species. Six facultative symbionts were identified. Regiella was the most commonly identified facultative symbiont, and multiple infections of facultative symbionts were detected in the majority of the samples. Ordination analyses and statistical tests show that the symbiont community of aphids feeding on plants from the family Ulmaceae were distinguishable from aphids feeding on other host plants. Species in Eriosomatinae feeding on different plants are likely to carry different symbiont compositions. The symbiont distributions seem to be not related to taxonomic distance and geographical distance. Our findings suggest that host plants can affect symbiont maintenance, and will improve our understanding of the interactions between aphids, their symbionts and ecological conditions.
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Gómez-Valero, Laura, Mario Soriano-Navarro, Vicente Pérez-Brocal, Abdelaziz Heddi, Andrés Moya, José Manuel García-Verdugo, and Amparo Latorre. "Coexistence of Wolbachia with Buchnera aphidicola and a Secondary Symbiont in the Aphid Cinara cedri." Journal of Bacteriology 186, no. 19 (October 1, 2004): 6626–33. http://dx.doi.org/10.1128/jb.186.19.6626-6633.2004.
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ABSTRACT Intracellular symbiosis is very common in the insect world. For the aphid Cinara cedri, we have identified by electron microscopy three symbiotic bacteria that can be characterized by their different sizes, morphologies, and electrodensities. PCR amplification and sequencing of the 16S ribosomal DNA (rDNA) genes showed that, in addition to harboring Buchnera aphidicola, the primary endosymbiont of aphids, C. cedri harbors a secondary symbiont (S symbiont) that was previously found to be associated with aphids (PASS, or R type) and an α-proteobacterium that belongs to the Wolbachia genus. Using in situ hybridization with specific bacterial probes designed for symbiont 16S rDNA sequences, we have shown that Wolbachia was represented by only a few minute bacteria surrounding the S symbionts. Moreover, the observed B. aphidicola and the S symbionts had similar sizes and were housed in separate specific bacterial cells, the bacteriocytes. Interestingly, in contrast to the case for all aphids examined thus far, the S symbionts were shown to occupy a similarly sized or even larger bacteriocyte space than B. aphidicola. These findings, along with the facts that C. cedri harbors the B. aphidicola strain with the smallest bacterial genome and that the S symbionts infect all Cinara spp. analyzed so far, suggest the possibility of bacterial replacement in these species.
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Ohbayashi, Tsubasa, Kazutaka Takeshita, Wataru Kitagawa, Naruo Nikoh, Ryuichi Koga, Xian-Ying Meng, Kanako Tago, et al. "Insect’s intestinal organ for symbiont sorting." Proceedings of the National Academy of Sciences 112, no. 37 (August 31, 2015): E5179—E5188. http://dx.doi.org/10.1073/pnas.1511454112.
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Symbiosis has significantly contributed to organismal adaptation and diversification. For establishment and maintenance of such host–symbiont associations, host organisms must have evolved mechanisms for selective incorporation, accommodation, and maintenance of their specific microbial partners. Here we report the discovery of a previously unrecognized type of animal organ for symbiont sorting. In the bean bug Riptortus pedestris, the posterior midgut is morphologically differentiated for harboring specific symbiotic bacteria of a beneficial nature. The sorting organ lies in the middle of the intestine as a constricted region, which partitions the midgut into an anterior nonsymbiotic region and a posterior symbiotic region. Oral administration of GFP-labeled Burkholderia symbionts to nymphal stinkbugs showed that the symbionts pass through the constricted region and colonize the posterior midgut. However, administration of food colorings revealed that food fluid enters neither the constricted region nor the posterior midgut, indicating selective symbiont passage at the constricted region and functional isolation of the posterior midgut for symbiosis. Coadministration of the GFP-labeled symbiont and red fluorescent protein-labeled Escherichia coli unveiled selective passage of the symbiont and blockage of E. coli at the constricted region, demonstrating the organ’s ability to discriminate the specific bacterial symbiont from nonsymbiotic bacteria. Transposon mutagenesis and screening revealed that symbiont mutants in flagella-related genes fail to pass through the constricted region, highlighting that both host’s control and symbiont’s motility are involved in the sorting process. The blocking of food flow at the constricted region is conserved among diverse stinkbug groups, suggesting the evolutionary origin of the intestinal organ in their common ancestor.
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Xu, Shifen, Liyun Jiang, Gexia Qiao, and Jing Chen. "The Bacterial Flora Associated with the Polyphagous Aphid Aphis gossypii Glover (Hemiptera: Aphididae) Is Strongly Affected by Host Plants." Microbial Ecology 79, no. 4 (December 4, 2019): 971–84. http://dx.doi.org/10.1007/s00248-019-01435-2.
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AbstractAphids live in symbiosis with a variety of bacteria, including the obligate symbiont Buchnera aphidicola and diverse facultative symbionts. The symbiotic associations for one aphid species, especially for polyphagous species, often differ across populations. In the present study, by using high-throughput 16S rRNA sequencing, we surveyed in detail the microbiota in natural populations of the cotton aphid Aphis gossypii in China and assessed differences in bacterial diversity with respect to host plant and geography. The microbial community of A. gossypii was dominated by a few heritable symbionts. Arsenophonus was the most dominant secondary symbiont, and Spiroplasma was detected for the first time. Statistical tests and ordination analyses showed that host plants rather than geography seemed to have shaped the associated symbiont composition. Special symbiont communities inhabited the Cucurbitaceae-feeding populations, which supported the ecological specialization of A. gossypii on cucurbits from the viewpoint of symbiotic bacteria. Correlation analysis suggested antagonistic interactions between Buchnera and coexisting secondary symbionts and more complicated interactions between different secondary symbionts. Our findings lend further support to an important role of the host plant in structuring symbiont communities of polyphagous aphids and will improve our understanding of the interactions among phytophagous insects, symbionts, and environments.
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Ashen, Jon B., and Lynda J. Goff. "Molecular and Ecological Evidence for Species Specificity and Coevolution in a Group of Marine Algal-Bacterial Symbioses." Applied and Environmental Microbiology 66, no. 7 (July 1, 2000): 3024–30. http://dx.doi.org/10.1128/aem.66.7.3024-3030.2000.
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ABSTRACT The phylogenetic relationships of bacterial symbionts from three gall-bearing species in the marine red algal genusPrionitis (Rhodophyta) were inferred from 16S rDNA sequence analysis and compared to host phylogeny also inferred from sequence comparisons (nuclear ribosomal internal-transcribed-spacer region). Gall formation has been described previously on two species ofPrionitis, P. lanceolata (from central California) and P. decipiens (from Peru). This investigation reports gall formation on a third related host,Prionitis filiformis. Phylogenetic analyses based on sequence comparisons place the bacteria as a single lineage within theRoseobacter grouping of the α subclass of the divisionProteobacteria (99.4 to 98.25% sequence identity among phylotypes). Comparison of symbiont and host molecular phylogenies confirms the presence of three gall-bearing algal lineages and is consistent with the hypothesis that these red seaweeds and their bacterial symbionts are coevolving. The species specificity of these associations was investigated in nature by whole-cell hybridization of gall bacteria and in the laboratory by using cross-inoculation trials. Whole-cell in situ hybridization confirmed that a single bacterial symbiont phylotype is present in galls on each host. In laboratory trials, bacterial symbionts were incapable of inducing galls on alternate hosts (including two non-gall-bearing species). Symbiont-host specificity in Prionitis gall formation indicates an effective ecological separation between these closely related symbiont phylotypes and provides an example of a biological context in which to consider the organismic significance of 16S rDNA sequence variation.
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Erwin, Patrick M., Lucía Pita, Susanna López-Legentil, and Xavier Turon. "Stability of Sponge-Associated Bacteria over Large Seasonal Shifts in Temperature and Irradiance." Applied and Environmental Microbiology 78, no. 20 (August 10, 2012): 7358–68. http://dx.doi.org/10.1128/aem.02035-12.
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ABSTRACTComplex microbiomes reside in marine sponges and consist of diverse microbial taxa, including functional guilds that may contribute to host metabolism and coastal marine nutrient cycles. Our understanding of these symbiotic systems is based primarily on static accounts of sponge microbiota, while their temporal dynamics across seasonal cycles remain largely unknown. Here, we investigated temporal variation in bacterial symbionts of three sympatric sponges (Irciniaspp.) over 1.5 years in the northwestern (NW) Mediterranean Sea, using replicated terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses of bacterial 16S rRNA gene sequences. Bacterial symbionts inIrciniaspp. exhibited host species-specific structure and remarkable stability throughout the monitoring period, despite large fluctuations in temperature and irradiance. In contrast, seawater bacteria exhibited clear seasonal shifts in community structure, indicating that different ecological constraints act on free-living and on symbiotic marine bacteria. Symbiont profiles were dominated by persistent, sponge-specific bacterial taxa, notably affiliated with phylogenetic lineages capable of photosynthesis, nitrite oxidation, and sulfate reduction. Variability in the sponge microbiota was restricted to rare symbionts and occurred most prominently in warmer seasons, coincident with elevated thermal regimes. Seasonal stability of the sponge microbiota supports the hypothesis of host-specific, stable associations between bacteria and sponges. Further, the core symbiont profiles revealed in this study provide an empirical baseline for diagnosing abnormal shifts in symbiont communities. Considering that these sponges have suffered recent, episodic mass mortalities related to thermal stresses, this study contributes to the development of model sponge-microbe symbioses for assessing the link between symbiont fluctuations and host health.
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Moran, Nancy A., Phat Tran, and Nicole M. Gerardo. "Symbiosis and Insect Diversification: an Ancient Symbiont of Sap-Feeding Insects from the Bacterial Phylum Bacteroidetes." Applied and Environmental Microbiology 71, no. 12 (December 2005): 8802–10. http://dx.doi.org/10.1128/aem.71.12.8802-8810.2005.
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ABSTRACT Several insect groups have obligate, vertically transmitted bacterial symbionts that provision hosts with nutrients that are limiting in the diet. Some of these bacteria have been shown to descend from ancient infections. Here we show that the large group of related insects including cicadas, leafhoppers, treehoppers, spittlebugs, and planthoppers host a distinct clade of bacterial symbionts. This newly described symbiont lineage belongs to the phylum Bacteroidetes. Analyses of 16S rRNA genes indicate that the symbiont phylogeny is completely congruent with the phylogeny of insect hosts as currently known. These results support the ancient acquisition of a symbiont by a shared ancestor of these insects, dating the original infection to at least 260 million years ago. As visualized in a species of spittlebug (Cercopoidea) and in a species of sharpshooter (Cicadellinae), the symbionts have extraordinarily large cells with an elongate shape, often more than 30 μm in length; in situ hybridizations verify that these correspond to the phylum Bacteroidetes. “Candidatus Sulcia muelleri” is proposed as the name of the new symbiont.
Dissertations / Theses on the topic "Bacterial symbiont"
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Russell, Shelbi Lianne. "Mode and Fidelity of Bacterial Symbiont Transmission and Its Impact on Symbiont Genome Evolution." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493576.
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Mutualistic symbioses have enabled the colonization of novel habitats and niches in a large array of eukaryotic and bacterial taxa. Reliable mechanisms of symbiont transmission between host generations are necessary to stabilize these associations over evolutionary time. Historically, symbionts have been categorized as either vertically transmitted from the parents to offspring or horizontally transmitted through the environment. The route between hosts influences how symbiont populations are connected between hosts and between geographic localities. Over evolutionary time vertical transmission leads to gene loss and genome erosion. Growing evidence from diverse associations suggests that modes utilizing both horizontal and vertical strategies exist, raising the question of how these “mixed modes” influence symbiont genome evolution. The overarching goal of my dissertation was to determine whether the mode of symbiont transmission in an obligate mutualism is consistent over evolutionary time and what impact transmission mode fidelity has on symbiont genome evolution. To test these questions, I used the chemosynthetic symbiosis between the marine bivalve Solemya velum and its gammaproteobacterial symbionts, which has been reported to transmit its symbionts vertically through the ovary, but bears none of the genomic hallmarks of strict vertical transmission.
In this work, I used population genomics of S. velum subpopulations sampled from five localities along the New England coast, from Massachusetts to North Carolina, to test for evidence of horizontal transmission in the evolutionary history of this species. These analyses revealed that symbionts and mitochondria do not exhibit concordant genealogies, divergent symbiont lineages have come into contact and recombined, and symbiont genomes have experienced large-scale structural changes mediated by mobile elements and horizontal gene transfer. In total, these lines of evidence indicate that a substantial amount of horizontal transmission has occurred in the recent history of this association. The vertical transmission route through host tissues was characterized via in situ hybridization to symbiont 16S rRNA in adult host tissues and by qPCR of the rhlE gene in spawned eggs. These data showed that symbionts are present at low abundance in the ovary, associated with the supportive cells and mature oocytes, and each spawned egg contains approximately 50-100 copies of the symbiont genome. Lastly, I tested for evidence of mixed transmission modes in symbiont populations contained within host tissues (each host gill contains more than a billion symbiont cells), by deep-coverage whole genome sequencing. Using a novel variant-calling procedure, I detected low amounts of genetic variation among symbiont genomes within a host relative to between hosts. However, the variant sites that were present were correlated in position along the genome, present on the same chromosome, and segregating in the symbiont population at large, suggesting that these variants arose via recombination with a variant symbiont genotype introduced by horizontal transmission.
In total, this work supports the existence of mixed transmission modes in symbiotic associations and indicates they have distinct consequences for symbiont evolution. Mixed modes may provide a best-of-both-worlds strategy to ensure that hosts acquire symbionts every generation while maintaining opportunities for recombination and acquisition of novel genetic elements. These results are relevant to understanding the impact of symbiont transmission mode on genome evolution in associations ranging from mutualisms to pathogenic infections.Biology, Organismic and Evolutionary
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Beinart, Roxanne Abra. "Linking bacterial symbiont physiology to the ecology of hydrothermal vent symbioses." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11270.
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Symbioses between prokaryotes and eukaryotes are ubiquitous in our biosphere, nevertheless, the effects of such associations on the partners' ecology and evolution are poorly understood. At hydrothermal vents, dominant invertebrate species typically host bacterial symbionts, which use chemical energy to fix carbon to nourish their hosts and themselves. In this dissertation, I present evidence that symbiont metabolism plays a substantive, if not major, role in habitat use by vent symbioses. A study of nearly 300 individuals of the symbiotic snail Alviniconcha sp. showed specificity between three host species and three specific symbiont phylotypes, as well as a novel lineage of Oceanospirillales. Additionally, this study revealed a structured distribution of each Alviniconcha-symbiont combination across ~300 km of hydrothermal vents that exhibited a gradient in geochemical composition, which is consistent with the physiological tendencies of the specific symbiont phylotypes. I also present a comparison of the in situ gene expression of the symbionts of Alviniconcha across that same geochemical gradient, which further implicates symbiont energy and nitrogen metabolism in governing the habitat partitioning of Alviniconcha. Finally, I present data that allies productivity and sulfur metabolism in three coexisting vent symbioses, demonstrating specific interaction with the environment. Three symbioses, namely the snails Alviniconcha and Ifremeria, and the mussel Bathymodiolus, are found around vents with differing concentrations of sulfide, thiosulfate and polysulfide. Using high-pressure, flow-through incubations and stable isotopic tracers, I quantified symbiont productivity via sulfide and thiosulfate oxidation, and provided the first demonstration of thiosulfate-dependent autotrophy in intact hydrothermal vent symbioses. I further demonstrated that vent symbioses can excrete thiosulfate and/or polysulfides, implicating them in substantively influencing the sulfur chemistry of their habitats. In summary, this dissertation demonstrates the importance of symbiont physiology to the ecology of prokaryote-eukaryote symbioses by revealing that symbiont activity may be critically important to the distribution of symbioses among specific niches, as well as can alter the geochemical environment through uptake and excretion of chemicals.
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Peterson, Brittany F., and Michael E. Scharf. "Metatranscriptome analysis reveals bacterial symbiont contributions to lower termite physiology and potential immune functions." BIOMED CENTRAL LTD, 2016. http://hdl.handle.net/10150/621516.
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Background: Symbioses throughout the animal kingdom are known to extend physiological and ecological capabilities to hosts. Insect-microbe associations are extremely common and are often related to novel niche exploitation, fitness advantages, and even speciation events. These phenomena include expansions in host diet, detoxification of insecticides and toxins, and increased defense against pathogens. However, dissecting the contributions of individual groups of symbionts at the molecular level is often underexplored due to methodological and analytical limitations. Termites are one of the best studied systems for physiological collaborations between host and symbiota; however, most work in lower termites (those with bacterial and protist symbionts) focuses on the eukaryotic members of this symbiotic consortium. Here we present a metatranscriptomic analysis which provides novel insights into bacterial contributions to the holobiont of the eastern subterranean termite, Reticulitermes flavipes, in the presence and absence of a fungal pathogen. Results: Using a customized ribodepletion strategy, a metatranscriptome assembly was obtained representing the host termite as well as bacterial and protist symbiota. Sequence data provide new insights into biosynthesis, catabolism, and transport of major organic molecules and ions by the gut consortium, and corroborate previous findings suggesting that bacteria play direct roles in nitrogen fixation, amino acid biosynthesis, and lignocellulose digestion. With regard to fungal pathogen challenge, a total of 563 differentially expressed candidate host and symbiont contigs were identified (162 up-and 401 downregulated; a/FDR = 0.05) including an upregulated bacterial amidohydrolase. Conclusions: This study presents the most complete bacterial metatranscriptome from a lower termite and provides a framework on which to build a more complete model of termite-symbiont interactions including, but not limited to, digestion and pathogen defense.
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Gibson, Cara. "Heritable Microbial Endosymbionts in Insects: Insights from the Study of a Parasitic Wasp and its Cockroach Host." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195875.
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Endosymbiosis is a pervasive phenomenon that has been a powerful force in insect evolution. In many well studied insect-bacterial associations, the bacteria can serve as reproductive manipulators, nutritional mutualists or defenders of their hosts. Fungi are also frequently associated with insects, and initial estimates suggest that these fungi are hyperdiverse. Saving a handful of examples, however, the functions of these fungi within insect hosts are largely unknown. This dissertation begins with a review that lays the conceptual groundwork for understanding bacterial and fungal endosymbiosis in insects. I make predictions about why one versus the other microbe might serve the insect, given any unique physiological, ecological or evolutionary conditions. I then aim to derive insights about microbial symbiosis by focusing on a particular system, that of brownbanded cockroaches, Supella longipalpa (Blattaria: Blattellidae) and their specialist wasp parasitoids, Comperia merceti (Hymenoptera: Encyrtidae). Here, I identify the symbiotic community of these two insects by using both culture-dependent and independent methods to characterize the vertically transmitted bacterial and fungal associates. Finally, I show that a heritable fungus in C. merceti, long presumed to be a mutualist, is parasitic under laboratory conditions: infected wasps incur fitness costs for housing the fungal symbiont relative to uninfected wasps. Additionally, although the fungus is not horizontally transmitted sexually, it is readily horizontally transmitted from the offspring of infected females to those of uninfected females that are using the same host.
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Hansen, Thorsten. "IDENTIFYING MECHANISMS OF HOST PLANT SPECIALIZATION IN APHIS CRACCIVORA AND ITS BACTERIAL SYMBIONTS." UKnowledge, 2018. https://uknowledge.uky.edu/entomology_etds/42.
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Many insects form close relationships with microbial symbionts. Insect symbionts can provide novel phenotypes to their hosts, including influencing dietary breadth. In the polyphagous cowpea aphid, Aphis craccivora, the facultative symbiont Arsenophonus improves aphid performance on one host plant (locust), but decreases performance on other plants. The goal of my thesis was to investigate the mechanism by which Arsenophonus facilitates use of locust. First, I assembled an Aphis craccivora-Arsenophonus-Buchnera reference transcriptome to conduct RNAseq analysis, comparing gene expression in aphids feeding on locust and fava, with and without Arsenophonus infection. Overall, few transcripts were differentially expressed. However, genes that were differentially expressed mapped to a variety of processes, including metabolism of glucose, cytoskeleton regulation, cold and drought regulation, and B-vitamin synthesis. These results imply that Arsenophonus is producing B-vitamins, which might be deficient in locust. In a second set of experiments, I used qPCR to test whether symbiont function across host plants might be mediated by bacterial titer. I measured relative Arsenophonus abundance across plants, and found Arsenophonus titer was variable, but generally greater on locust than fava. In summary, my results suggest that Arsenophonus synthesis of B-vitamins should be further investigated and may be mediated by bacterial titer.
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Wilson, Alex, Helen Dunbar, Gregory Davis, Wayne Hunter, David Stern, and Nancy Moran. "A dual-genome microarray for the pea aphid, Acyrthosiphon pisum, and its obligate bacterial symbiont, Buchnera aphidicola." BioMed Central, 2006. http://hdl.handle.net/10150/610396.
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BACKGROUND:The best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont Buchnera aphidicola. Buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. We have used a single microarray to examine gene expression in the pea aphid, Acyrthosiphon pisum, and its resident Buchnera. Very little is known of gene expression in aphids, few studies have examined gene expression in Buchnera, and no study has examined simultaneously the expression profiles of a host and its symbiont. Expression profiling of aphids, in studies such as this, will be critical for assigning newly discovered A. pisum genes to functional roles. In particular, because aphids possess many genes that are absent from Drosophila and other holometabolous insect taxa, aphid genome annotation efforts cannot rely entirely on homology to the best-studied insect systems. Development of this dual-genome array represents a first attempt to characterize gene expression in this emerging model system.RESULTS:We chose to examine heat shock response because it has been well characterized both in Buchnera and in other insect species. Our results from the Buchnera of A. pisum show responses for the same gene set as an earlier study of heat shock response in Buchnera for the host aphid Schizaphis graminum. Additionally, analyses of aphid transcripts showed the expected response for homologs of known heat shock genes as well as responses for several genes with unknown functional roles.CONCLUSION:We examined gene expression under heat shock of an insect and its bacterial symbiont in a single assay using a dual-genome microarray. Further, our results indicate that microarrays are a useful tool for inferring functional roles of genes in A. pisum and other insects and suggest that the pea aphid genome may contain many gene paralogs that are differentially regulated.
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König, Sten. "The bacterial symbiont in the shallow water lucinids Codakia orbicularis and C. orbiculata analyzed by physiological proteogenomics." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066700.
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Les bivalves côtiers Codakia orbicularis et C. orbiculata, de la famille des Lucinidae, abritent des Gammaprotéobactéries endosymbiotiques sulfo-oxydantes dans leurs branchies. Ces deux bivalves vivent dans les herbiers à Thalassia testudinum et hébergent la même bactérie symbiotique selon les analyses effectuées à partir des séquences d’ADNr 16S. Lors de période de stabulation, la population bactérienne symbiotique décroit alors qu’il n’y a pas, dans le même temps, de relargage des symbiotes observé. Des analyses en cytochimie ont montré une forte activité d’enzymes lysosomales lors de ces épisodes de privation de nourriture et de soufre. Il a ainsi été montré que les symbiotes peuvent servir directement de source de nourriture aux bivalves pour survivre lors de ces périodes de crise. Le transfert de carbone des symbiotes vers l’hôte peut être flexible et pourrait consister en un simple transfert de matière organique ou "milking", dans des conditions normales de nutrition et de digestion des symbiotes et devenir du "farming", dans des conditions de stabulation. Jusqu’à ce jour, le symbiote reste non cultivable. De ce fait, l’utilisation de techniques indépendantes de la culture comme les approches –omics ont été mises en place pour étudier la physiologie de cette bactérie symbiotique. Le génome du symbiote a été analysé par Next Generation Sequencing (NGS) permettant ainsi d’obtenir les bases du protéome et ainsi de pouvoir analyser la physiologie du symbiote. Dans ce travail, le protéome des bactéries a été analysé sous différentes conditions. L’oxydation des sulfures est une des voies métaboliques clés du symbiote de Codakia. Cette voie fait très probablement appel au système Sox périplasmique, ainsi qu’à une sulfite réductase cytoplasmique (DsrAB), une APS réductase (AprAB) et une ATP sulfurylase (SopT). De plus, deux autres enzymes additionnelles d’oxydation des sulfures ont pu être mises en évidence dans l’espace périplasmique du symbiote telle que la quinone réductase (Sqr) et la sulfide déhydrogénase (FccAB). Les gènes des enzymes du cycle de Calvin Benson Bassham (CBB) ne semblent pas être tous présents dans le génome du symbiote. Les protéines de la RuBisCO sont abondamment exprimées. Il semblerait que la régénération du ribulose-1,5-bisphosphate soit effectuée de façon non conventionnelle via une phosphofructokinase PPi-dépendante. Une autre caractéristique du CBB est qu’il y a deux formes différentes de RuBisCO codées dans le génome du symbiote. Les deux formes sont exprimées en même temps, mais la forme I de la RuBisCO est 50 fois plus exprimée que la forme II. En plus de la vie autotrophique, plusieurs gènes nécessaires à une vie hétérotrophique sont présents dans le génome. Dans le protéome, les enzymes de la glycolyse et du cycle TCA sont faiblement exprimées. Les protéines du métabolisme du glycogène ont également été identifiées dans le protéome. De plus, plusieurs types de transporteurs comme ABC, TRAP et PTS sont présents dans le génome et certaines formes d’expression de ces transporteurs ont pu être suspectées, y compris lors de la vie intracellulaire du symbiote. De façon inattendue, un groupe de gènes nif est présent dans le génome permettant la fixation de l’azote atmosphérique par le symbiote. Les protéines codées par les gènes clés, comme la nitrogénase NifH/K/D, ont été abondamment trouvées dans le protéome. De plus, l’analyse du protéome montre une régulation forte de ces protéines dans des conditions de stabulation du bivalve hôte. La rubrerythrine est fortement exprimée et servirait à protéger la nitrogénase de l’oxygène au sein des bacteriocytes. L’endosymbiote bactérien code également pour un système de sécrétion de type 6 (T6SS) pour le transport de molécules bactériennes effectrices à travers les membranes du cytoplasme de la cellule hôte et jouerait un rôle possible de communication directe avec l’hôteThe shallow water bivalves Codakia orbicularis and Codakia orbiculata, both belonging to the family Lucinidae, harbor endosymbiotic sulfur-oxidizing gamma-Proteobacteria in their gills. The bivalves live in seagrass beds of Thalassia testudinum and harbor the same bacterial symbionts according to 16S rDNA sequence analysis. During starvation, the symbiont population decreases while no release of symbionts were observed. We observed lysosomal enzyme activity during sulfide and food starvation with cytochemical staining methods. We suggest that the host uses symbionts as a nutrient source to survive a hunger crisis. The carbon transfer from the symbionts to the host could be flexible and could consist in transfer of organic matter, "milking", under normal feeding conditions and digestion of the symbionts, "farming", under starved conditions. Until now the symbiont alone is not cultivable. Therefore, cultivation-independent techniques, like -omics approaches were used to analyze the physiology of the symbiont. Next generation sequencing (NGS) was employed to sequence the genomes of symbionts from both hosts, display the backbone for proteomics. The soluble- and membrane-associated symbiont proteomes were analyzed during different conditions. The oxidation of sulfide is one key metabolic pathway of the Codakia symbiont, most probably using the periplasmic Sox-system, a cytoplasmatic sulfite reductase (DsrAB), an APS reductase (AprAB) and an ATP sulfurylase (SopT). Furthermore, indications for two additional putative sulfide oxidation systems in the periplasmic space, the sulfide quinone reductase (Sqr) and the sulfide dehydrogenase (FccAB), could be found. The Calvin Benson Bassham cycle (CBB) of the symbiont is not completely encoded in the genome. The key genes, RuBisCO, are abundantly expressed. It is assumed that the regeneration of the ribulose-1,5-bisphosphate is performed unconventionally via a PPi-dependent phosphofructokinase. Another feature of the CBB is that two different forms of RuBisCO are encoded in the genome. Both are expressed at the same time, but RuBisCO form I is about 50x times more expressed. Additional to the autotrophic lifestyle, all genes for the heterotrophic lifestyle are encoded in the genome. In the proteome, the enzymes related to glycolysis and TCA-cycle were low expressed. Interestingly, proteins for glycogen metabolism were identified in the proteome. Additionally, several types of transporters like ABC, TRAP and PTS are encoded in the genome. In the proteome several indications were found for an expression of these transporters, even in the endosymbiotic lifestyle. Unexpectedly, in the genome a nif gene cluster is encoded for gaseous nitrogen fixation as ammonium source. The key genes, the nitrogenase NifH/K/D, were abundantly identified in proteome. Further, the proteome analyses indicate a strictly down-regulation of these proteins under starvation conditions. Rubrerythrin, a strongly expressed protein and is predicted to protect the nitrogenase against oxygen stress. The bacterial endosymbionts encode a specialized secretion system type 6 (T6SS) for the transport of bacterial effector molecules through the membranes to the host cytoplasm and display one possibility for a direct "communication" with the host. In summary, genomics and proteomics analyses of the Codakia symbiont improved the knowledge about the metabolism of the symbiont in lucinid bivalves.. The genomics and proteomics data generated in this study can be used as a basis for further in-depth analyses of the physiology of the symbionts and interaction with the host
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Flórez, Laura Victoria [Verfasser], Martin [Gutachter] Kaltenpoth, Christian [Gutachter] Hertweck, and Martha S. [Gutachter] Hunter. "Burkholderia as bacterial symbionts of Lagriinae beetles : symbiont transmission, prevalence and ecological significance in Lagria villosa and Lagria hirta (Coleoptera: Tenebrionidae) / Laura Victoria Flórez ; Gutachter: Martin Kaltenpoth, Christian Hertweck, Martha S. Hunter." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/117760261X/34.
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Wilkinson, Peter Graham. "Characterisation of the bacterial flora associated with the grey field slug Deroceras reticulatum and assessment of its suitability as a target for biological control." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5276.
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The field slug Deroceras reticulatum is a major pest in UK agriculture and amidst growing concern and regulatory pressures surrounding chemical molluscicides, innovation is required to advance the current repertoire of slug controls. This study set out to investigate the bacteria associated with D. reticulatum to assess their importance to the slug and potential as a target for biological control. Slug gut bacterial isolates identified using the phenotypical API system (BioMérieux) and 16S rRNA gene sequencing, were mainly soil-dwelling organisms of the phyla Proteobacteria and Bacteriodetes some of which may be important in human or plant disease. A ribosomal intergenic spacer analysis (RISA) was developed to study microbial communities in the slug gut. Slugs had an average species richness of 12 and comparing the bacterial communities in slugs from different locations yielded a mean similarity of 0.159 (Jaccard index) which was significantly lower than similarity indices of slugs collected within a single location (Mean Jaccard index 0.205, p<0.001, ANOVA). Cloning and sequencing of RISA bands common to slugs and slug eggs, but absent from the surrounding soil and plants identified bacteria for future investigation as potential beneficial symbionts. Bacteria extracted from the slug gut were tested for sensitivity to 16 antibiotics and greatest inhibition of growth was observed for chloramphenicol, gentamicin and tetracycline. These antibiotics administered to slugs by feeding and injection caused a reduction in gut-associated bacteria in plate counts, and in bacterial 16S rDNA quantities estimated by real-time quantitative PCR. Field collected D. reticulatum has a large transient gut bacterial population which is reduced upon starvation to a low background level. No significant detrimental effect of antibiotic treatment on the fitness and survival of the slugs was seen, in some instances control slugs suffered greater mortality than slugs that had been injected with antibiotic. Slugs that died during bioassays had a significantly greater amount of bacterial 16S rDNA in their gut than slugs that were sacrificed as healthy individuals suggesting the presence of a bacterial pathogen. This study has found little evidence that a bacterial symbiont may exist and be important for optimal fitness and survival of D. reticulatum, but insight into slug associated bacteria will be valuable in the direction of future studies in this field.
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Andam, Cheryl Marie Palacay. "Role of lateral gene transfer in the evolution of legume nodule symbionts." Diss., Online access via UMI:, 2007.
Find full textBooks on the topic "Bacterial symbiont"
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Clements, A. N. The biology of mosquitoes: Viral and bacterial pathogens and bacterial symbionts. Cambridge, MA: CABI, 2011.
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Honor thy symbionts. United States]: [CreateSpace Independent Publishing Platform], 2012.
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Kirchman, David L. Genomes and meta-omics for microbes. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0005.
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The sequencing of entire genomes of microbes grown in pure cultures is now routine. The sequence data from cultivated microbes have provided insights into these microbes and their uncultivated relatives. Sequencing studies have found that bacterial genomes range from 0.18 Mb (intracellular symbiont) to 13 Mb (a soil bacterium), whereas genomes of eukaryotes are much bigger. Genomes from eukaryotes and prokaryotes are organized quite differently. While bacteria and their small genomes often grow faster than eukaryotes, there is no correlation between genome size and growth rates among the bacteria examined so far. Genomic studies have also highlighted the importance of genes exchanged (“horizontal gene transfer”) between organisms, seemingly unrelated, as defined by rRNA gene sequences. Microbial ecologists use metagenomics to sequence all microbes in a community. This approach has revealed unsuspected physiological processes in microbes, such as the occurrence of a light-driven proton pump, rhodopsin, in bacteria (dubbed proteorhodopsin). Genomes from single cells isolated by flow cytometry have also provided insights about the ecophysiology of both bacteria and protists. Oligotrophic bacteria have streamlined genomes, which are usually small but with a high fraction of genomic material devoted to protein-encoding genes, and few transcriptional control mechanisms. The study of all transcripts from a natural community, metatranscriptomics, has been informative about the response of eukaryotes as well as bacteria to changing environmental conditions.
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Hunt, David J., and K. B. Nguyen. Entomopathogenic Nematodes: Systematics, Phylogeny and Bacterial Symbionts. BRILL, 2007.
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(Editor), Khuong B. Nguyen, and David J. Hunt (Editor), eds. Entomopathogenic Nematodes: Systematics, Phylogeny and Bacterial Symbionts (Nematology Monographs and Perspectives). Brill Academic Publishers, 2008.
Find full textBook chapters on the topic "Bacterial symbiont"
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ffrench-Constant, Richard H., Andrea Dowling, Michelle Hares, Guowei Yang, and Nicholas Waterfield. "Photorhabdus: Genomics of a Pathogen and Symbiont." In Bacterial Pathogenomics, 419–39. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555815530.ch16.
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Göttfert, Michael, Philipp Grob, Silvia Rossbach, Hans-Martin Fischer, Beat Thöny, Denise Anthamatten, Ines Kullik, and Hauke Hennecke. "Bacterial Genes Involved in the Communication Between Soybean and Its Root Nodule Symbiont, Bradyrhizobium Japonicum." In NATO ASI Series, 295–301. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74158-6_36.
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Crotti, Elena, Bessem Chouaia, Alberto Alma, Guido Favia, Claudio Bandi, Kostas Bourtzis, and Daniele Daffonchio. "Acetic Acid Bacteria as Symbionts of Insects." In Acetic Acid Bacteria, 121–42. Tokyo: Springer Japan, 2016. http://dx.doi.org/10.1007/978-4-431-55933-7_5.
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Ritchie, Kim B. "Bacterial Symbionts of Corals and Symbiodinium." In Beneficial Microorganisms in Multicellular Life Forms, 139–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21680-0_9.
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Damann, Franklin E. "Bacterial Symbionts and Taphonomic Agents of Humans." In Taphonomy of Human Remains: Forensic Analysis of the Dead and the Depositional Environment, 155–66. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781118953358.ch12.
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Rodríguez-Rubio, Lorena, Pedro Blanco-Picazo, and Maite Muniesa. "Are Phages Parasites or Symbionts of Bacteria?" In Biocommunication of Phages, 143–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45885-0_7.
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Haygood, Margo G., and Seana K. Davidson. "Bacterial Symbionts of the Bryostatin-Producing Bryozoan Bugula Neritina." In New Developments in Marine Biotechnology, 281–84. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-5983-9_60.
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Attardo, Geoffrey M., Francesca Scolari, and Anna Malacrida. "Bacterial Symbionts of Tsetse Flies: Relationships and Functional Interactions Between Tsetse Flies and Their Symbionts." In Results and Problems in Cell Differentiation, 497–536. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-51849-3_19.
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Nealson, K., T. M. Schmidt, and B. Bleakley. "Luminescent Bacteria: Symbionts of Nematodes Am) Pathogens of Insects." In Cell to Cell Signals in Plant, Animal and Microbial Symbiosis, 101–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73154-9_7.
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Mohan, Sharad. "Entomopathogenic Nematodes and Their Bacterial Symbionts as Lethal Bioagents of Lepidopteran Pests." In Soil Biology, 273–88. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-14499-3_13.
Full textConference papers on the topic "Bacterial symbiont"
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Chu, Dong. "Effects of a bacterial symbiont on the competitive ability and fitness of host whitefly." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.91798.
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Cordaux, Richard. "Evolution of new sex chromosomes by lateral genome transfer of bacterial symbiont in pillbug." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.94155.
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Yakubovskaya, A. I., I. A. Kameneva, M. V. Gritchin, Ya V. Pukhalsky, and A. V. Slavinskaya. "Biological activity of Oryza sativa L. rhizosphere after introduction of associative bacteria strains." In РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ПРИРОДНЫХ РЕСУРСОВ В АГРОЦЕНОЗАХ. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-15.05.2020.22.
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The article presents the results of studies of biological activity in the rhizosphere system associative bacteria − Oryza sativa L. The pre-sowing treatment of seeds with associative symbionts activates biological processes in the rhizosphere and contributes to the increased productivity of Oryza sativa L. The number of grains per spike rose by 28.2-59.0%, 1000-grain weight – by 6.2%-10.6% compared to control.
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Bennett, Gordon M. "Genome evolution and phylogenomics of heritable bacterial symbionts in insects." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.95552.
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Mech, Angela M. "Determining the role of bacterial symbionts on the heat tolerance ofAdelges tsugae." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.112083.
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Weldon, Stephanie Ray. "Swapping symbionts: Consequences of bacterial partner replacement in a nested mealybug mutualism." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.110221.
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Majeed, Muhammad, Chun-Sen Ma, Ahmed Raza, and Zhang Bo. "The relationship between thermal tolerance of cereal aphids and their bacterial symbionts." In The 1st International Electronic Conference on Entomology. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/iece-10521.
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Hu, Zu-Qing. "Ecological impacts of secondary bacteria symbionts onSitobion avenae(Fabricius) (Hemiptera: Aphididae)." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.106162.
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Crotti, Elena. "Honey bee bacterial symbionts: Probiotic effect against the causal agent of American foulbrood disease." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.92837.
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Calderon, Olga. "Isolation, identification, and characterization of Cerambycid beetles and their bacterial symbionts in three New York City urban parks." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.113693.
Full textReports on the topic "Bacterial symbiont"
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Gottlieb, Yuval, Bradley Mullens, and Richard Stouthamer. investigation of the role of bacterial symbionts in regulating the biology and vector competence of Culicoides vectors of animal viruses. United States Department of Agriculture, June 2015. http://dx.doi.org/10.32747/2015.7699865.bard.
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Symbiotic bacteria have been shown to influence host reproduction and defense against biotic and abiotic stressors, and this relates to possible development of a symbiont-based control strategy. This project was based on the hypothesis that symbionts have a significant impact on Culicoides fitness and vector competence for animal viruses. The original objectives in our proposal were: 1. Molecular identification and localization of the newly-discovered symbiotic bacteria within C. imicola and C. schultzei in Israel and C. sonorensis in California. 2. Determination of the prevalence of symbiotic bacteria within different vector Culicoides populations. 3. Documentation of specific symbiont effects on vector reproduction and defense: 3a) test for cytoplasmic incompatibility in Cardinium-infected species; 3b) experimentally evaluate the role of the symbiont on infection or parasitism by key Culicoides natural enemies (iridescent virus and mermithid nematode). 4. Testing the role(s) of the symbionts in possible protection against infection of vector Culicoides by BTV. According to preliminary findings and difficulties in performing experimental procedures performed in other insect symbiosis systems where insect host cultures are easily maintained, we modified the last two objectives as follows: Obj. 3, we tested how symbionts affected general fitness of Israeli Culicoides species, and thoroughly described and evaluated the correlation between American Culicoides and their bacterial communities in the field. We also tried alternative methods to test symbiont-Culicoides interactions and launched studies to characterize low-temperature stress tolerances of the main US vector, which may be related to symbionts. Obj. 4, we tested the correlation between EHDV (instead of BTV) aquisition and Cardinium infection. Culicoides-bornearboviral diseases are emerging or re-emerging worldwide, causing direct and indirect economic losses as well as reduction in animal welfare. One novel strategy to reduce insects’ vectorial capacity is by manipulating specific symbionts to affect vector fitness or performance of the disease agent within. Little was known on the bacterial tenants occupying various Culicoides species, and thus, this project was initiated with the above aims. During this project, we were able to describe the symbiont Cardinium and whole bacterial communities in Israeli and American Culicoides species respectively. We showed that Cardinium infection prevalence is determined by land surface temperature, and this may be important to the larval stage. We also showed no patent significant effect of Cardinium on adult fitness parameters. We showed that the bacterial community in C. sonorensis varies significantly with the host’s developmental stage, but it varies little across multiple wastewater pond environments. This may indicate some specific biological interactions and allowed us to describe a “core microbiome” for C. sonorensis. The final set of analyses that include habitat sample is currently done, in order to separate the more intimately-associated bacteria from those inhabiting the gut contents or cuticle surface (which also could be important). We were also able to carefully study other biological aspects of Culicoides and were able to discriminate two species in C. schultzei group in Israel, and to investigate low temperature tolerances of C. sonorensis that may be related to symbionts. Scientific implications include the establishment of bacterial identification and interactions in Culicoides (our work is cited in other bacteria-Culicoides studies), the development molecular identification of C. schultzei group, and the detailed description of the microbiome of the immature and matched adult stages of C. sonorensis. Agricultural implications include understanding of intrinsic factors that govern Culicoides biology and population regulation, which may be relevant for vector control or reduction in pathogen transmission. Being able to precisely identify Culicoides species is central to understanding Culicoides borne disease epidemiology.
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Gottlieb, Yuval, and Bradley A. Mullens. Might Bacterial Symbionts Influence Vectorial Capacity of Biting Midges for Ruminant Viruses? United States Department of Agriculture, September 2010. http://dx.doi.org/10.32747/2010.7699837.bard.
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- Original objectives and revision: The feasibility study performed in the last year was aimed at determining the symbiotic profiles of eight selected Culicoidesspecies in Israel and the USA by: Comparing bacterial communities among geographic populations of primary bluetongue virus (BTV) vectors. Comparing bacterial communities between adults of field-collected, mammal-feeding BTV vectors and non-vectors. Comparing bacterial communities within and between mammal feeders and bird feeders, with special attention to species with unique immature habitats. We made an effort to collect the eight species during the beginning of the project, however, due to the short available collection season, and the significant changes in habitats available for Israeli Culicoides, we initially determined the symbiotic profile of five species: two BTV vectors (C. sonorensis, C. imicola), one mammal feeders with unknown vectoring ability (C. schultzei), one bird feeder (C. crepuscularis), and one unique habitat species (C. cacticola). In addition, upon preliminary symbiont identification we focused our effort on relevant specific symbionts. Background: Biting midges (Culicoides, Diptera: Ceratopogonidae) are vectors of many major viral diseases affecting farm animals, including BT, which is listed among the most damaging by the World Organization for Animal Health (OIE) and has recently emerged in completely unexpected areas (Northern Europe). One of the strategies to reduce the vectorial capacity of insect vectors is by manipulating their specific symbionts either to affect the vector species or to influence performance of the disease agent within it. Despite significant efforts to elucidate the vectorial capacity of certain Culicoidesspecies, and the critical basis of variability in infection, almost no attention has been given to symbiotic interactions between the vector and its bacterial tenants. It is now established that bacterial symbionts have major influences on their host biology, and may interact with disease agents vectored by their hosts. - Major conclusions, solutions, achievements: During the feasibility project we have found two major bacterial symbionts in Israeli and American Culicoides. In Israel we discovered that C. imicola, a known vector of BT, and C. schultzeigp. a suspected vector of BT, carry the symbiotic bacterium Cardinium, a reproductive manipulator symbiont. In C. imicolathe infection rate was close to 50%, and in C. schultzeiit was lower, and restricted to one of two species within Schultzeigroup. In 3 American species (C. sonorensis, C. crepuscularis, C. cacticola) we found the bacterium Burkholderiasp. In all species tested we have also found other bacterial species in diverse quantities and frequencies. - Implications, both scientific and agricultural: Finding specific symbionts in Culicoidesvector species is the first step in developing symbiont based control (SBC) strategies. Both identified symbionts are known from other insects, and Cardiniumis also known as a reproductive manipulator that can cause cytoplasmic incompatibility, an important phenomenon that can be used for spreading desired traits in infected populations. The role of the symbionts in Culicoideshost can be target for manipulation to reduce the vectorial capacity of the host by either changing its fitness so that it is unable to serve as a vector, or by directly changing the symbiont in a way that will affect the performance of the disease agent in its vector. Since Burkholderiaperhaps can be cultured independently of the host, it is a promising candidate for the later option. Thus, we have now opened the door for studying the specific interactions between symbionts and vector species.
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Fisher, Charles, and James Childress. Host-Symbiont Interactions between a Marine Mussel and Methanotrophic Bacterial Endosymbionts. Fort Belvoir, VA: Defense Technical Information Center, April 1991. http://dx.doi.org/10.21236/ada235562.
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Fisher, Charles, and James Childress. Host-Symbiont Interactions Between a Marine Mussel and Methanotrophic Bacterial Endosymbionts. Fort Belvoir, VA: Defense Technical Information Center, April 1991. http://dx.doi.org/10.21236/ada244810.
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Zchori-Fein, Einat, Judith K. Brown, and Nurit Katzir. Biocomplexity and Selective modulation of whitefly symbiotic composition. United States Department of Agriculture, June 2006. http://dx.doi.org/10.32747/2006.7591733.bard.
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Whiteflies are sap-sucking insects that harbor obligatory symbiotic bacteria to fulfill their dietary needs, as well as a facultative microbial community with diverse bacterial species. The sweetpotato whitefly Bemisia tabaci (Gennadius) is a severe agricultural pest in many parts of the world. This speciesconsists of several biotypes that have been distinguished largely on the basis of biochemical or molecular diagnostics, but whose biological significance is still unclear. The original objectives of the project were (i) to identify the specific complement of prokaryotic endosymbionts associated with select, well-studied, biologically and phylogeographically representative biotypes of B. tabaci, and (ii) to attempt to 'cure’ select biotypes of certain symbionts to permit assessment of the affect of curing on whitefly fitness, gene flow, host plant preference, and virus transmission competency.To identify the diversity of bacterial community associated with a suite of phylogeographically-diverseB. tabaci, a total of 107 populations were screened using general Bacteria primers for the 16S rRNA encoding gene in a PCR. Sequence comparisons with the available databases revealed the presence of bacteria classified in the: Proteobacteria (66%), Firmicutes (25.70%), Actinobacteria (3.7%), Chlamydiae (2.75%) and Bacteroidetes (<1%). Among previously identified bacteria, such as the primary symbiont Portiera aleyrodidarum, and the secondary symbionts Hamiltonella, Cardinium and Wolbachia, a Rickettsia sp. was detected for the first time in this insect family. The distribution, transmission, and localization of the Rickettsia were studied using PCR and fluorescence in situ hybridization (FISH). Rickettsia was found in all 20 Israeli B. tabaci populations screened as well as some populations screened in the Arizona laboratory, but not in all individuals within each population. FISH analysis of B. tabaci eggs, nymphs and adults, revealed a unique concentration of Rickettsia around the gut and follicle cells as well as its random distribution in the haemolymph, but absence from the primary symbiont housing cells, the bacteriocytes. Rickettsia vertical transmission on the one hand and its partial within-population infection on the other suggest a phenotype that is advantageous under certain conditions but may be deleterious enough to prevent fixation under others.To test for the possible involvement of Wolbachia and Cardiniumin the reproductive isolation of different B. tabacibiotypes, reciprocal crosses were preformed among populations of the Cardinium-infected, Wolbachia-infected and uninfected populations. The crosses results demonstrated that phylogeographically divergent B. tabaci are reproductively competent and that cytoplasmic incompatibility inducer-bacteria (Wolbachia and Cardinium) both interfered with, and/or rescued CI induced by one another, effectively facilitating bidirectional female offspring production in the latter scenario.This knowledge has implications to multitrophic interactions, gene flow, speciation, fitness, natural enemy interactions, and possibly, host preference and virus transmission. Although extensive and creative attempts undertaken in both laboratories to cure whiteflies of non-primary symbionts have failed, our finding of naturally uninfected individuals have permitted the establishment of Rickettsia-, Wolbachia- and Cardinium-freeB. tabaci lines, which are been employed to address various biological questions, including determining the role of these bacteria in whitefly host biology.
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Hunter, Martha S., and Einat Zchori-Fein. Rickettsia in the whitefly Bemisia tabaci: Phenotypic variants and fitness effects. United States Department of Agriculture, September 2014. http://dx.doi.org/10.32747/2014.7594394.bard.
Full textAbstract:
The sweet potato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is a major pest of vegetables, field crops, and ornamentals worldwide. This species harbors a diverse assembly of facultative, “secondary” bacterial symbionts, the roles of which are largely unknown. We documented a spectacular sweep of one of these, Rickettsia, in the Southwestern United States in the B biotype (=MEAM1) of B. tabaci, from 1% to 97% over 6 years, as well as a dramatic fitness benefit associated with it in Arizona but not in Israel. Because it is critical to understand the circumstances in which a symbiont invasion can cause such a large change in pest life history, the following objectives were set: 1) Determine the frequency of Rickettsia in B. tabaci in cotton across the United States and Israel. 2) Characterize Rickettsia and B. tabaci genotypes in order to test the hypothesis that genetic variation in either partner is responsible for differences in phenotypes seen in the two countries. 3) Determine the comparative fitness effects of Rickettsia phenotypes in B. tabaci in Israel and the United States. For Obj. 1, a survey of B. tabaci B samples revealed the distribution of Rickettsia across the cotton-growing regions of 13 sites from Israel and 22 sites from the USA. Across the USA, Rickettsia frequencies were heterogeneous among regions, but were generally at frequencies higher than 75% and close to fixation in some areas, whereas in Israel the infection rates were lower and declining. The distinct outcomes of Rickettsia infection in these two countries conform to previouslyreported phenotypic differences. Intermediate frequencies in some areas in both countries may indicate a cost to infection in certain environments or that the frequencies are in flux. This suggests underlying geographic differences in the interactions between bacterial symbionts and the pest. Obj. 2, Sequences of several Rickettsia genes in both locations, including a hypervariableintergenic spacer gene, suggested that the Rickettsia genotype is identical in both countries. Experiments in the US showed that differences in whitefly nuclear genotype had a strong influence on Rickettsia phenotype. Obj. 3. Experiments designed to test for possible horizontal transmission of Rickettsia, showed that these bacteria are transferred from B. tabaci to a plant, moved inside the phloem, and could be acquired by other whiteflies. Plants can serve as a reservoir for horizontal transmission of Rickettsia, a mechanism that may explain the occurrence of phylogenetically-similarsymbionts among unrelated phytophagous insect species. This plant-mediated transmission route may also exist in other insect-symbiont systems, and since symbionts may play a critical role in the ecology and evolution of their hosts, serve as an immediate and powerful tool for accelerated evolution. However, no such horizontal transmission of Rickettsia could be detected in the USA, underlining the difference between the interaction in both countries, or between B. tabaci and the banded wing whitefly on cotton in the USA (Trialeurodes sp. nr. abutiloneus) and the omnivorous bug Nesidiocoristenuis. Additionally, a series of experiments excluded the possibility that Rickettsia is frequently transmitted between B. tabaci and its parasitoid wasps Eretmocerusmundus and Encarsiapergandiella. Lastly, ecological studies on Rickettsia effects on free flight of whiteflies showed no significant influence of symbiont infection on flight. In contrast, a field study of the effects of Rickettsia on whitefly performance on caged cotton in the USA showed strong fitness benefits of infection, and rapid increases in Rickettsia frequency in competition population cages. This result confirmed the benefits to whiteflies of Rickettsia infection in a field setting.
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Phillips, Donald, and Yoram Kapulnik. Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7613012.bard.
Full textAbstract:
Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions