Project description:To determine the optimal RNA-Seq approach for animal host-bacterial symbiont analysis, we compared transcriptome bias, depth and coverage achieved by two different mRNA capture and sequencing strategies applied to the marine demosponge Amphimedon queenslandica holobiont, for which genomes of the animal host and three most abundant bacterial symbionts are available.
Project description:Host-microbe interactions are virtually bidirectional, benefiting both the host and microbial sides. It is becoming increasingly recognized the influence of the microbe on many aspects of host physiology and diseases, but whether/how the host affects their symbionts is poorly characterized. Here, we reported that the host acts as a critical factor to shape the lifestyle of their symbionts in the Drosophila and bacteria model system. First, we observe that Drosophila larvae play a pivotal role in competing with pathogenic symbionts in the co-existing niche. More specifically, host larvae antagonize symbionts by deconstructing the surface slick, preventing outgrowth and antagonizing the pathogenicity of S. marcescens. Furthermore, Drosophila larvae cause the shift in the transcriptomic profile of S. marcescens, characterized with the upregulated expression of genes related to bacterial proliferation and growth and the downregulated expression of genes related to bacterial pathogenicity. More importantly, advances in bacterial single-cell RNA sequencing provide opportunities to reveal transcriptional variation, including toxic factors, across individual cells and a subpopulation clustering of isogenic bacterial populations. Finally, we found that AMPs from larvae recapitulated the response of S. marcescens to the presence of Drosophila larvae. Altogether, these findings provide an insight into the pivotal roles of the host in influencing the potential pathogens' lifecycle switching from commensalism to pathogenicity, opening the door to a better understanding of the ecological relationships between the host and microbe.
Project description:Host-microbe interactions are virtually bidirectional, benefiting both the host and microbial sides. It is becoming increasingly recognized the influence of the microbe on many aspects of host physiology and diseases, but whether/how the host affects their symbionts is poorly characterized. Here, we reported that the host acts as a critical factor to shape the lifestyle of their symbionts in the Drosophila and bacteria model system. First, we observe that Drosophila larvae play a pivotal role in competing with pathogenic symbionts in the co-existing niche. More specifically, host larvae antagonize symbionts by deconstructing the surface slick, preventing outgrowth and antagonizing the pathogenicity of S. marcescens. Furthermore, Drosophila larvae cause the shift in the transcriptomic profile of S. marcescens, characterized with the upregulated expression of genes related to bacterial proliferation and growth and the downregulated expression of genes related to bacterial pathogenicity. More importantly, advances in bacterial single-cell RNA sequencing provide opportunities to reveal transcriptional variation, including toxic factors, across individual cells and a subpopulation clustering of isogenic bacterial populations. Finally, we found that AMPs from larvae recapitulated the response of S. marcescens to the presence of Drosophila larvae. Altogether, these findings provide an insight into the pivotal roles of the host in influencing the potential pathogens' lifecycle switching from commensalism to pathogenicity, opening the door to a better understanding of the ecological relationships between the host and microbe.
Project description:The mammalian gastrointestinal tract harbors thousands of bacterial species that include symbionts as well as potential pathogens. The immune responses that limit access of these bacteria to underlying tissue remain poorly defined. In this study, we used microarrays to uncover the transcriptional responses that occur in small intestinal γδ intraepithelial lymphocytes following bacterial challenge. γδ intraepithelial lymphocytes (γδ IEL) were isolated by flow cytometry from the small intestines of germ-free mice, or from age- and sex-matched conventionally-raised counterparts. We extracted RNAs from these purified γδ IEL for analysis on Affymetrix DNA microarrays. The mice were all >8 weeks in age, and each sample represents a pool of RNAs from 5-8 mice.
Project description:The mammalian gastrointestinal tract harbors thousands of bacterial species that include symbionts as well as potential pathogens. The immune responses that limit access of these bacteria to underlying tissue remain poorly defined. In this study, we used microarrays to uncover the transcriptional responses that occur in small intestinal γδ intraepithelial lymphocytes following bacterial challenge.
Project description:The Lucinidae is a large family of marine bivalves. They occur in diverse habitats from shallow-water seagrass sediments to deep-sea hydrothermal vents. All members of this family so far investigated host intracellular sulfur-oxidizing symbionts that belong to the Gammaproteobacteria. We recently discovered the capability for nitrogen fixation in draft genomes of the symbionts of Loripes lucinalis from the Bay of Fetovaia, Elba, Italy. With proteomics, we investigated whether the genes for nitrogen fixation are expressed by the symbionts.
Project description:Despite their key role in numerous natural compounds, β-amino acids have rarely been studied as substrates for microbial degradation. Fermentation of the newly isolated Paraburkholderia strain BS115 and the type strain P. phytofirmans PsJN with β-phenylalanine (β-PA) as sole nitrogen source revealed (S)-selective transamination of β-PA to the corresponding β-keto acid by both strains, accompanied by substantial formation of acetophenone (AP) from spontaneous decarboxylation of the emerging β-keto acid. While the PsJN culture became stationary after entire (S)-β-PA consumption, BS115 showed further growth at a considerably slower rate, consuming (R)-β-PA without generation of AP which points to a different degradation mechanism for this enantiomer. This is the first report on degradation of both enantiomers of any β-amino acid by one single bacterial strain.