Project description:C. jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human foodborne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion as evidenced by gentamicin-protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC demonstrated Cia secretion as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene as judged by B-galactosidase reporter assays and real-time RT-PCR. Microarray analysis revealed that DOC induced the expression of virulence genes (i.e., ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrate that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation to identify genes expressed by C. jejuni in response to in vivo-like culture conditions. Keywords: Stress response
Project description:The Type VI Secretion System (T6SS) has important roles relating to bacterial antagonism, subversion of host cells, and niche colonisation. Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis worldwide and is a commensal coloniser of birds. Although recently discovered, the T6SS biological functions and identities of its effectors are still poorly defined in C. jejuni. Here, we perform a comprehensive bioinformatic analysis of the C. jejuni T6SS by investigating the prevalence and genetic architecture of the T6SS in 513 publicly available genomes using C. jejuni 488 strain as reference. A unique and conserved T6SS cluster associated with the Campylobacter jejuni Integrated Element 3 (CJIE3) was identified in the genomes of 117 strains. Analyses of the T6SS-positive 488 strain against the T6SS-negative C. jejuni RM1221 strain and the T6SS-positive plasmid pCJDM202 carried by C. jejuni WP2-202 strain defined the "T6SS-containing CJIE3" as a pathogenicity island, thus renamed as Campylobacter jejuni Pathogenicity Island-1 (CJPI-1). Analysis of CJPI-1 revealed two canonical VgrG homologues, CJ488_0978 and CJ488_0998, harbouring distinct C-termini in a genetically variable region downstream of the T6SS operon. CJPI-1 was also found to carry a putative DinJ-YafQ Type II toxin-antitoxin (TA) module, conserved across pCJDM202 and the genomic island CJIE3, as well as several open reading frames functionally predicted to encode for nucleases, lipases, and peptidoglycan hydrolases. This comprehensive in silico study provides a framework for experimental characterisation of T6SS-related effectors and TA modules in C. jejuni.
Project description:Campylobacter jejuni is the most prevalent cause of foodborne bacterial enteritis worldwide. This study aims at the characterisation of pathomechanisms and signalling in Campylobacter-induced diarrhoea in the human mucosa. During routine colonoscopy, biopsies were taken from patients suffering from campylobacteriosis. RNA-seq of colon biopsies was performed to describe Campylobacter jejuni-mediated effects. Mucosal mRNA profiles of acutely infected patients and healthy controls were generated by deep sequencing using Illumina HiSeq 2500. This data provide the basis for subsequent upstream regulator analysis.
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.
Project description:Campylobacter jejuni is a major zoonotic pathogen transmitted to humans via the food chain. C. jejuni is prevalent in chickens, a natural reservoir for this pathogenic organism. Due to the importance of macrolide antibiotics in clinical therapy of human campylobacteriosis, development of macrolide resistance in Campylobacter has become a concern for public health.To facilitate understanding the molecular basis associated with the fitness difference between Erys and Eryr Campylobacter, we compared the transcriptomes between ATCC 700819 and its isogenic Eryr transformant T.L.101 using DNA microarray.