Project description:Background: Gonad differentiation is an essential function for all sexually reproducing species, and many aspects of these developmental processes are highly conserved among the metazoa. The colonial ascidian, Botryllus schlosseri is a chordate model organism which offers two unique traits that can be utilized to characterize the genes underlying germline development: a colonial life history and variable fertility. These properties allow individual genotypes to be isolated at different stages of fertility and gene expression can be characterized comprehensively. Results: Here we characterized the transcriptome of both fertile and infertile colonies throughout blastogenesis (asexual development) using differential expression analysis. We identified genes (as few as 7 and as many as 647) regulating fertility in Botryllus at each stage of blastogenesis. Several of these genes appear to drive gonad maturation, as they are expressed by follicle cells surrounding both testis and oocyte precursors. Spatial and temporal expression of differentially expressed genes was analyzed by in situ hybridization, confirming expression in developing gonads. Conclusion: We have identified several genes expressed in developing and mature gonads in B. schlosseri. Analysis of genes upregulated in fertile animals suggests a high level of conservation of the mechanisms regulating fertility between basal chordates and vertebrates. mRNA profiles of seven infertile stages from infertile Botryllus schlosseri colonies (each in triplicates) and seven stages of fertile Botryllus schlosseri colonies (each in triplicates) using Illumina deep sequencing and analyzed for differential expression between each stage.
Project description:Background: Gonad differentiation is an essential function for all sexually reproducing species, and many aspects of these developmental processes are highly conserved among the metazoa. The colonial ascidian, Botryllus schlosseri is a chordate model organism which offers two unique traits that can be utilized to characterize the genes underlying germline development: a colonial life history and variable fertility. These properties allow individual genotypes to be isolated at different stages of fertility and gene expression can be characterized comprehensively. Results: Here we characterized the transcriptome of both fertile and infertile colonies throughout blastogenesis (asexual development) using differential expression analysis. We identified genes (as few as 7 and as many as 647) regulating fertility in Botryllus at each stage of blastogenesis. Several of these genes appear to drive gonad maturation, as they are expressed by follicle cells surrounding both testis and oocyte precursors. Spatial and temporal expression of differentially expressed genes was analyzed by in situ hybridization, confirming expression in developing gonads. Conclusion: We have identified several genes expressed in developing and mature gonads in B. schlosseri. Analysis of genes upregulated in fertile animals suggests a high level of conservation of the mechanisms regulating fertility between basal chordates and vertebrates.
Project description:A genomic overview of in vivo binding of a transcription factor ZicL in the ascidian gastrula embryo. ZicL is a key regulator of the early ascidian development, and so called 'master-regulatory genes' for mesodermal and neural tissues are under the control of ZicL. Keywords: ChIP-chip
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 human gut microbiota is a metabolic organ whose cellular composition is determined by a dynamic process of selection and competition. To identify microbial genes required for establishment of human symbionts in the gut, we developed an approach (insertion-sequencing, or INSeq) based on a mutagenic transposon that allows capture of adjacent chromosomal DNA to define its genomic location. We used massively parallel sequencing to monitor the relative abundance of tens of thousands of transposon mutants of a saccharolytic human gut bacterium, Bacteroides thetaiotaomicron, as they established themselves in wild-type and immunodeficient gnotobiotic mice, in the presence or absence of other human gut commensals. In vivo selection transforms this population, revealing functions necessary for survival in the gut: we show how this selection is influenced by community composition and competition for nutrients (vitamin B12). INSeq provides a broadly applicable platform to explore microbial adaptation to the gut and other ecosystems. Keywords: Other 57 samples analyzed, 1 of these is the reference (input) sample