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  • 1
    In: mBio, American Society for Microbiology, Vol. 10, No. 6 ( 2019-12-24)
    Abstract: Plants are a difficult food resource to use, and herbivorous insects have evolved a variety of mechanisms that allow them to fully exploit this poor nutritional resource. One such mechanism is the maintenance of bacterial symbionts that aid in host plant feeding and development. The majority of these intracellular symbionts have highly eroded genomes that lack many key regulatory genes; consequently, it is unclear if these symbionts can respond to changes in the insect’s diet to facilitate host plant use. There is emerging evidence that symbionts with highly eroded genomes express small RNAs (sRNAs), some of which potentially regulate gene expression. In this study, we sought to determine if the reduced genome of the nutritional symbiont ( Buchnera ) in the pea aphid responds to changes in the aphid’s host plant diet. Using transcriptome sequencing (RNA-seq), Buchnera sRNA expression profiles were characterized within two Buchnera life stages when pea aphids fed on either alfalfa or fava bean. Overall, this study demonstrates that Buchnera sRNA expression changes not only with life stage but also with changes in aphid host plant diet. Of the 321 sRNAs characterized in this study, 47% were previously identified and 22% showed evidence of conservation in two or more Buchnera taxa. Functionally, 13 differentially expressed sRNAs were predicted to target genes related to pathways involved in essential amino acid biosynthesis. Overall, results from this study reveal that host plant diet influences the expression of conserved and lineage-specific sRNAs in Buchnera and that these sRNAs display distinct host plant-specific expression profiles among biological replicates. IMPORTANCE In general, the genomes of intracellular bacterial symbionts are reduced compared to those of free-living relatives and lack many key regulatory genes. Many of these reduced genomes belong to obligate mutualists of insects that feed on a diet that is deficient in essential nutrients, such as essential amino acids. It is unclear if these symbionts respond with their host to changes in insect diet, because of their reduced regulatory capacity. Emerging evidence suggests that these symbionts express small RNAs (sRNAs) that regulate gene expression at the posttranscriptional level. Therefore, in this study, we sought to determine if the reduced genome of the nutritional symbiont Buchnera in the pea aphid responds to changes in the aphid’s host plant diet. This study demonstrates for the first time that Buchnera sRNAs, some conserved in two or more Buchnera lineages, are differentially expressed when aphids feed on different plant species and potentially target genes within essential amino acid biosynthesis pathways.
    Type of Medium: Online Resource
    ISSN: 2161-2129 , 2150-7511
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2019
    detail.hit.zdb_id: 2557172-2
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  • 2
    In: mBio, American Society for Microbiology, Vol. 7, No. 6 ( 2016-12-30)
    Abstract: Bees are important pollinators of agricultural plants. Our study documents the ability of Gilliamella apicola , a dominant gut bacterium in honey bees and bumble bees, to utilize several sugars that are harmful to bee hosts. Using genome sequencing and growth assays, we found that the ability to metabolize certain toxic carbohydrates is directly correlated with the presence of their respective degradation pathways, indicating that metabolic potential can be accurately predicted from genomic data in these gut symbionts. Strains vary considerably in their range of utilizable carbohydrates, which likely reflects historical horizontal gene transfer and gene deletion events. Unlike their bee hosts, G. apicola bacteria are not detrimentally affected by growth on mannose-containing medium, even in strains that cannot metabolize this sugar. These results suggest that G. apicola may be an important player in modulating nutrition in the bee gut, with ultimate effects on host health.
    Type of Medium: Online Resource
    ISSN: 2161-2129 , 2150-7511
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2016
    detail.hit.zdb_id: 2557172-2
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  • 3
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2000
    In:  Journal of Plant Growth Regulation Vol. 19, No. 2 ( 2000-06), p. 113-130
    In: Journal of Plant Growth Regulation, Springer Science and Business Media LLC, Vol. 19, No. 2 ( 2000-06), p. 113-130
    Type of Medium: Online Resource
    ISSN: 0721-7595 , 1435-8107
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2000
    detail.hit.zdb_id: 1462091-1
    SSG: 12
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  • 4
    In: Seminars in Immunology, Elsevier BV, Vol. 24, No. 1 ( 2012-2), p. 3-8
    Type of Medium: Online Resource
    ISSN: 1044-5323
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2012
    detail.hit.zdb_id: 1471753-0
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  • 5
    Online Resource
    Online Resource
    The Company of Biologists ; 2015
    In:  Journal of Experimental Biology Vol. 218, No. 12 ( 2015-06-01), p. 1968-1973
    In: Journal of Experimental Biology, The Company of Biologists, Vol. 218, No. 12 ( 2015-06-01), p. 1968-1973
    Abstract: The new technology of next-generation sequencing is changing our perceptions of the form and function of the biological world. The emerging data reveal an array of microbes that is more vast and more central to all biological processes than previously appreciated. Further, evidence is accumulating that the alliances of microbes with one another and with constituents of the macrobiological world are critical for the health of the biosphere. This contribution summarizes the basic arguments as to why, when considering the biochemical adaptations of animals, we should integrate the roles of their microbial partners.
    Type of Medium: Online Resource
    ISSN: 1477-9145 , 0022-0949
    Language: English
    Publisher: The Company of Biologists
    Publication Date: 2015
    detail.hit.zdb_id: 1482461-9
    SSG: 12
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  • 6
    In: Journal of Experimental Biology, The Company of Biologists
    Abstract: Associations between animals and microbes affect not only the immediate tissues where they occur, but also the entire host. Metabolomics, the study of small biomolecules generated during metabolic processes, provides a window into how mutualistic interactions shape host biochemistry. The Hawaiian bobtail squid, Euprymna scolopes, is amenable to metabolomic studies of symbiosis because the host can be reared with or without its species-specific symbiont, Vibrio fischeri. In addition, unlike many invertebrates, the host squid has a closed circulatory system. This feature allows a direct sampling of the refined collection of metabolites circulating through the body, a focused approach that has been highly successful with mammals. Here, we show that rearing E. scolopes without its natural symbiont significantly affected one quarter of the more than 100 hemolymph metabolites defined by gas chromatography mass-spectrometry analysis. Further, as in mammals, which harbor complex consortia of bacterial symbionts, the metabolite signature oscillated on symbiont-driven daily rhythms and was dependent on the sex of the host. Thus, our results provide evidence that the population of even a single symbiont species can influence host hemolymph biochemistry as a function of symbiotic state, host sex, and circadian rhythm.
    Type of Medium: Online Resource
    ISSN: 1477-9145 , 0022-0949
    Language: English
    Publisher: The Company of Biologists
    Publication Date: 2020
    detail.hit.zdb_id: 1482461-9
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    American Society for Microbiology ; 2000
    In:  Journal of Bacteriology Vol. 182, No. 16 ( 2000-08-15), p. 4578-4586
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 182, No. 16 ( 2000-08-15), p. 4578-4586
    Abstract: The bioluminescent bacterium Vibrio fischeri and juveniles of the squid Euprymna scolopes specifically recognize and respond to one another during the formation of a persistent colonization within the host's nascent light-emitting organ. The resulting fully developed light organ contains brightly luminescing bacteria and has undergone a bacterium-induced program of tissue differentiation, one component of which is a swelling of the epithelial cells that line the symbiont-containing crypts. While the luminescence ( lux ) genes of symbiotic V. fischeri have been shown to be highly induced within the crypts, the role of these genes in the initiation and persistence of the symbiosis has not been rigorously examined. We have constructed and examined three mutants ( luxA , luxI , and luxR ), defective in either luciferase enzymatic or regulatory proteins. All three are unable to induce normal luminescence levels in the host and, 2 days after initiating the association, had a three- to fourfold defect in the extent of colonization. Surprisingly, these lux mutants also were unable to induce swelling in the crypt epithelial cells. Complementing, in trans , the defect in light emission restored both normal colonization capability and induction of swelling. We hypothesize that a diminished level of oxygen consumption by a luciferase-deficient symbiotic population is responsible for the reduced fitness of lux mutants in the light organ crypts. This study is the first to show that the capacity for bioluminescence is critical for normal cell-cell interactions between a bacterium and its animal host and presents the first examples of V. fischeri genes that affect normal host tissue development.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2000
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    American Society for Microbiology ; 2008
    In:  Applied and Environmental Microbiology Vol. 74, No. 3 ( 2008-02), p. 633-644
    In: Applied and Environmental Microbiology, American Society for Microbiology, Vol. 74, No. 3 ( 2008-02), p. 633-644
    Abstract: Bacterial lipid A is an important mediator of bacterium-host interactions, and secondary acylations added by HtrB and MsbB can be critical for colonization and virulence in pathogenic infections. In contrast, Vibrio fischeri lipid A stimulates normal developmental processes in this bacterium's mutualistic host, Euprymna scolopes , although the importance of lipid A structure in this symbiosis is unknown. To further examine V. fischeri lipid A and its symbiotic function, we identified two paralogs of htrB (designated htrB1 and htrB2 ) and an msbB gene in V. fischeri ES114 and demonstrated that these genes encode lipid A secondary acyltransferases. htrB2 and msbB are found on the Vibrio “housekeeping” chromosome 1 and are conserved in other Vibrio species. Mutations in htrB2 and msbB did not impair symbiotic colonization but resulted in phenotypic alterations in culture, including reduced motility and increased luminescence. These mutations also affected sensitivity to sodium dodecyl sulfate, kanamycin, and polymyxin, consistent with changes in membrane permeability. Conversely, htrB1 is located on the smaller, more variable vibrio chromosome 2, and an htrB1 mutant was wild-type-like in culture but appeared attenuated in initiating the symbiosis and was outcompeted 2.7-fold during colonization when mixed with the parent. These data suggest that htrB2 and msbB play conserved general roles in vibrio biology, whereas htrB1 plays a more symbiosis-specific role in V. fischeri .
    Type of Medium: Online Resource
    ISSN: 0099-2240 , 1098-5336
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2008
    detail.hit.zdb_id: 223011-2
    detail.hit.zdb_id: 1478346-0
    SSG: 12
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  • 9
    Online Resource
    Online Resource
    American Society for Microbiology ; 2004
    In:  Applied and Environmental Microbiology Vol. 70, No. 3 ( 2004-03), p. 1434-1441
    In: Applied and Environmental Microbiology, American Society for Microbiology, Vol. 70, No. 3 ( 2004-03), p. 1434-1441
    Abstract: The influence of bacteria on the cytoskeleton of animal cells has been studied extensively only in pathogenic associations. We characterized changes in host cytoskeletal actin induced by the bacterial partner during the onset of a cooperative animal-bacteria association using the squid-vibrio model. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis revealed that Vibrio fischeri induced a dramatic increase in actin protein abundance in the bacteria-associated host tissues during the onset of the symbiosis. Immunocytochemistry revealed that this change in actin abundance correlated with a two- to threefold increase in actin in the apical cell surface of the epithelium-lined ducts, the route of entry of symbionts into host tissues. Real-time reverse transcriptase PCR and in situ hybridization did not detect corresponding changes in actin mRNA. Temporally correlated with the bacteria-induced changes in actin levels was a two- to threefold decrease in duct circumference, a 20% loss in the average number of cells interfacing with the duct lumina, and dramatic changes in duct cell shape. When considered with previous studies of the biomechanical and biochemical characteristics of the duct, these findings suggest that the bacterial symbionts, upon colonizing the host organ, induce modifications that physically and chemically limit the opportunity for subsequent colonizers to pass through the ducts. Continued study of the squid-vibrio system will allow further comparisons of the mechanisms by which pathogenic and cooperative bacteria influence cytoskeleton dynamics in host cells.
    Type of Medium: Online Resource
    ISSN: 0099-2240 , 1098-5336
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2004
    detail.hit.zdb_id: 223011-2
    detail.hit.zdb_id: 1478346-0
    SSG: 12
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  • 10
    In: Environmental Microbiology, Wiley, Vol. 16, No. 12 ( 2014-12), p. 3669-3682
    Abstract: Most bacterial species make transitions between habitats, such as switching from free living to symbiotic niches. We provide evidence that a galaxin protein, EsGal1 , of the squid E uprymna scolopes participates in both: ( i ) selection of the specific partner V ibrio fischeri from the bacterioplankton during symbiosis onset and, ( ii ) modulation of V . fischeri growth in symbiotic maintenance. We identified two galaxins in transcriptomic databases and showed by quantitative reverse‐transcriptase polymerase chain reaction that one ( esgal1 ) was dominant in the light organ. Further, esgal1 expression was upregulated by symbiosis, a response that was partially achieved with exposure to symbiont cell‐envelope molecules. Confocal immunocytochemistry of juvenile animals localized EsGal1 to the apical surfaces of light‐organ epithelia and surrounding mucus, the environment in which V . fischeri cells aggregate before migration into the organ. Growth assays revealed that one repeat of EsGal1 arrested growth of G ram‐positive bacterial cells, which represent the cell type first ‘winnowed’ during initial selection of the symbiont. The EsGal1 ‐derived peptide also significantly decreased the growth rate of V . fischeri in culture. Further, when animals were exposed to an anti‐ EsGal1 antibody, symbiont population growth was significantly increased. These data provide a window into how hosts select symbionts from a rich environment and govern their growth in symbiosis.
    Type of Medium: Online Resource
    ISSN: 1462-2912 , 1462-2920
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2014
    detail.hit.zdb_id: 2020213-1
    SSG: 12
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