Project description:On going efforts are directed at understanding the mutualism between the gut microbiota and the host in breast-fed versus formula-fed infants. Due to the lack of tissue biopsies, no investigators have performed a global transcriptional (gene expression) analysis of the developing human intestine in healthy infants. As a result, the crosstalk between the microbiome and the host transcriptome in the developing mucosal-commensal environment has not been determined. In this study, we examined the host intestinal mRNA gene expression and microbial DNA profiles in full term 3 month-old infants exclusively formula fed (FF) (n=6) or breast fed (BF) (n=6) from birth to 3 months. Host mRNA microarray measurements were performed using isolated intact sloughed epithelial cells in stool samples collected at 3 months. Microbial composition from the same stool samples was assessed by metagenomic pyrosequencing. Both the host mRNA expression and bacterial microbiome phylogenetic profiles provided strong feature sets that clearly classified the two groups of babies (FF and BF). To determine the relationship between host epithelial cell gene expression and the bacterial colony profiles, the host transcriptome and functionally profiled microbiome data were analyzed in a multivariate manner. From a functional perspective, analysis of the gut microbiota's metagenome revealed that characteristics associated with virulence differed between the FF and BF babies. Using canonical correlation analysis, evidence of multivariate structure relating eleven host immunity / mucosal defense-related genes and microbiome virulence characteristics was observed. These results, for the first time, provide insight into the integrated responses of the host and microbiome to dietary substrates in the early neonatal period. Our data suggest that systems biology and computational modeling approaches that integrate “-omic” information from the host and the microbiome can identify important mechanistic pathways of intestinal development affecting the gut microbiome in the first few months of life. KEYWORDS: infant, breast-feeding, infant formula, exfoliated cells, transcriptome, metagenome, multivariate analysis, canonical correlation analysis 12 samples, 2 groups
Project description:we used next-generation sequencing technology to characterise mRNA-seq of control- and hypoxia-treated T. fasciatus livers to elucidate the molecular mechanisms of cold adaptation. We were able to find mRNA pairs using bioinformatics analysis.
Project description:Despite considerable speculation for the role of cytosine (DNA) methylation in biological and molecular processes in insects, direct functional tests are lacking. Here we provide evidence for the functional role of the maintenance DNA methyltransferase 1 (Dnmt1) in an insect using experimental manipulation. Through RNA interference (RNAi) we successfully post-transcriptionally knocked down Dnmt1 in ovarian tissue of the hemipteran Oncopeltus fasciatus (the large milkweed bug). Individuals depleted for dnmt1, and subsequently DNA methylation, failed to reproduce. Manipulating the levels of DNA methylation did not result in changes in overall gene expression. Furthermore, reductions in levels of DNA methylation at transposable elements (TEs) did not lead to large-scale reactivation of TE transcription. Despite the lack of a causal relationship between reduced DNA methylation and gene expression in the tissue we surveyed, eggs were inviable revealing an important function of DNA methylation in O. fasciatus. Our work provides direct experimental evidence for a functional role of Dnmt1 and DNA methylation in insects and presents O. fasciatus as a tractable model for further exploration of the function of DNA methylation in other tissues and life history circumstances for insects.
Project description:Besides promoting inflammation by mobilizing lipid mediators, secreted phospholipase A2 group IIA (sPLA2-IIA) prevents bacterial infection by degrading bacterial membranes. Here we show that despite the restricted intestinal expression of sPLA2-IIA in BALB/c mice, its genetic deletion leads to amelioration of cancer and exacerbation of psoriasis in distal skin. Intestinal expression of sPLA2-IIA is reduced after antibiotics treatment or under germ-free conditions, suggesting its upregulation by gut microbiota. Metagenome, transcriptome and metabolome analyses have revealed that sPLA2-IIA deficiency alters the gut microbiota, accompanied by notable changes in the intestinal expression of genes related to immunity and metabolism as well as the levels of various blood metabolites and fecal bacterial lipids, suggesting that sPLA2-IIA contributes to shaping of the gut microbiota. The skin phenotypes in Pla2g2a–/– mice are lost when they are co-housed with littermate wild-type mice, resulting in mixing of the microbiota between the genotypes, or when they are housed in a more stringent pathogen-free facility, where Pla2g2a expression in wild-type mice is low and the gut microbial compositions in both genotypes are nearly identical. Thus, our results highlight a new aspect of sPLA2-IIA as a modulator of gut microbiota, perturbation of which affects distal skin responses.