Campylobacter jejuni gene expression in germ-free mice
ABSTRACT: Expression arrays comparing Campylobacter jejuni NCTC11168 during growth in the cecum of germ-free C57 BL/6 IL-10 knockout mice to C. jejuni NCTC11168 during growth in Bolton broth. Four biological replicates comparing C. jejuni NCTC11168 growth in vivo to in vitro. Two biological replicates were dye swaps.
Project description:A highly pathogenic Campylobacter jejuni clone has recently emerged as the major cause of Campylobacter-associated sheep abortion in the U.S. and is also associated with foodborne gastroenteritis in humans. A distinct phenotype of this clone is its ability to induce bacteremia and abortion. To facilitate understanding the pathogenic mechanisms of this hyper virulent clone, the differences in global gene expression patterns between this hyper virulent clone (IA3902) and a non-abortifacient strain (NCTC 11168) were compared by DNA microarray. One-condition experiment, IA3902 vs NCTC11168. Biological replicates: 3 IA3902 , 3 NCTC11168. One replicate per array.
Project description:Campylobacter jejuni is currently the leading cause of bacterial gastroenteritis in humans. Comparison of multiple Campylobacter strains revealed a high genetic and phenotypic diversity. However, little is known about differences in transcriptome organization, gene expression, and small RNA (sRNA) repertoires. Here we present the first comparative primary transcriptome analysis based on the differential RNA–seq (dRNA–seq) of four C. jejuni isolates. Our approach includes a novel, generic method for the automated annotation of transcriptional start sites (TSS), which allowed us to provide genome-wide promoter maps in the analyzed strains. These global TSS maps are refined through the integration of a SuperGenome approach that allows for a comparative TSS annotation by mapping RNA–seq data of multiple strains into a common coordinate system derived from a whole-genome alignment. Considering the steadily increasing amount of RNA–seq studies, our automated TSS annotation will not only facilitate transcriptome annotation for a wider range of pro- and eukaryotes but can also be adapted for the analysis among different growth or stress conditions. Our comparative dRNA–seq analysis revealed conservation of most TSS, but also single-nucleotide-polymorphisms (SNP) in promoter regions, which lead to strain-specific transcriptional output. Furthermore, we identified strain-specific sRNA repertoires that could contribute to differential gene regulation among strains. In addition, we identified a novel minimal CRISPR-system in Campylobacter of the type-II CRISPR subtype, which relies on the host factor RNase III and a trans-encoded sRNA for maturation of crRNAs. This minimal system of Campylobacter, which seems active in only some strains, employs a unique maturation pathway, since the crRNAs are transcribed from individual promoters in the upstream repeats and thereby minimize the requirements for the maturation machinery. Overall, our study provides new insights into strain-specific transcriptome organization and sRNAs, and reveals genes that could modulate phenotypic variation among strains despite high conservation at the DNA level. Our dRNA-seq study of multiple C. jejuni strains represents the first comparative analysis of the primary transcriptomes of multiple strains and provides new insights into riboregulation in this bacterial pathogen.
Project description:Expression arrays comparing Campylobacter jejuni NCTC11168 during growth in the cecum of germ-free C57 BL/6 IL-10 knockout mice to C. jejuni NCTC11168 during growth in Bolton broth. Overall design: Four biological replicates comparing C. jejuni NCTC11168 growth in vivo to in vitro. Two biological replicates were dye swaps.
Project description:Expression arrays comparing Campylobacter jejuni 11168 before and after serial passage in C57 BL/6 IL-10 deficient mice. Transcript abundance was compared between C. jejuni variants during growth in the ceca of C57 BL/6 IL-10 deficient germ-free mice. Unpassaged (p0) C. jejuni 11168 was compared to the same strain after three passages (p3) through the mice. Biological replicates: 4; 2 biological replicates were dye swaps.
Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. Previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple series of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni NCTC11168 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (68E1, 68E8 and 68E64) with its parent wild-type strain NCTC11168. The assay identified a small number of genes that showed significant changes (q-value<0.1) in expression in the low-level macrolide resistant strain 68E1, while a large number of gene showing significant changes in intermedia-level resistant stran 68E8 and high-level resistant strain 68 E64. The up-regulated genes in the resistant strains are involved in miscellaneous periplasmic proteins, efflux protienand putative aminotransferase, while the majority of the down-regulated genes are involved in electron transport,lipoprotein, heat shock protein and unknown function proteins. These findings suggest that there is not much change in low-level macrolide resistant C. jejuni strain. The over-expression of efflux pump and periplasmic protein was involved in the development of resistance to macrolide in C. jejuni. Keywords: macrolide resistant C. jejuni selected from NCTC 11168 step-wise selection. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni NCTC11168 cDNA samples or macrolide resistant C.jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus, there were four biological replicates of each sample.
Project description:N-linked glycosylation is an essential virulence determinant in Campylobacter jejuni, the major causative agent of gastroenteritis in the developed world. Glycosylation is encoded by the pgl gene cluster which encodes for the biosynthesis and attachment of a conserved heptasaccharide glycan to proteins in the C. jejuni periplasm. Over 80 membrane-associated proteins have been identified, however the functional role played by glycan attachment is almost completely unknown. We used quantitative proteomics by label-based and targeted strategies to examine glycosylation negative C. jejuni in comparison to wild-type. These technical approaches were considered as ‘discovery’ (label-based) and ‘validation’ data sets in our subsequent analysis. Inclusion of a glycosylation restored strain enabled us to further exploit the proteomics data to exclude non-specific protein abundance changes that could be considered as off-target effects. These data have provided a reference set of changes associated with protein N-glycosylation that could subsequently be tested by phenotypic analysis to determine the role of this modification in Campylobacter biology.
Project description:Strain specific growth of C. jejuni on fucose has been linked to a plasticity region of the chromosome (PR2) and confers a competitive advantage during intestinal colonization. Growth on fucose induces gene expression of PR2 genes, but the regulatory mechanism of the structural genes involved with fucose utilization is unknown. Additionally, the mechanism of fucose dissimilation by C. jejuni is not known since no fucose catabolism homologs are found in the C. jejuni genome. Transcriptional profiles of C. jejuni grown with and without fucose may provide insight in to the genes that are necessary for fucose utilization. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni wild type strain NCTC 11168. Each sample represents one competitive hybridization: sham-treated NCTC 11168 v.s. 25mM fucose treated NCTC 11168. There were four biological replicates of each sample with a dye swap introduced in alternating replicates. Samples were independently grown, treated and harvested.
Project description:While growing in the human intestine, C. jejuni grows within the mucus layer. The largest constituents of this layer are the large mucin glycoproteins. A transcriptomic profile of C. jejuni NCTC11168 growing in a mucin-containing minimal medium seeks to describe the effect of the presence of mucin proteins on the transcriptome of C. jejuni. Microarray data was collected from three independent biological replicates and 9 technical replicates for each biological replicate.
Project description:Strain specific growth of C. jejuni on fucose has been linked to a plasticity region of the chromosome (PR2) and confers a competitive advantage during intestinal colonization. Growth on fucose induces gene expression of PR2 genes, but the regulatory mechanism of the structural genes involved with fucose utilization is unknown. A mutant was constructed to examine the role of Cj0480c, a putative IclR-type transcriptional regulator, on PR2 gene expression. Transcriptional profiles of wild-type C. jejuni and the Cj0480c mutant strain grown without fucose may provide insight in to the extent of the fucose regulon and genes that are necessary for fucose utilization. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni wild type strain NCTC 11168. Each sample represents one competitive hybridization: wild-type NCTC 11168 v.s. Cj0480c isogenic mutant. There were four biological replicates of each sample with a dye swap introduced in alternating replicates. Samples were independently grown, treated and harvested.