Transcriptomic profiling of Campylobacter jejuni strains: IA3902 vs NCTC11168
ABSTRACT: 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: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:Campylobacter jejuni has become the predominant cause of sheep abortions in the U.S. However, little is know about the genetic diversity among the isolates collected from different time periods. In this study, the genetic diversity of sheep abortion isolates of C. jejuni was investigated by Array-based CGH Each isolate was compared to IA3902, a dye-swap replicate was applied for each isolate
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:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. Previous findings suggested 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, erythromycin-resistant C. jejuni mutant (R) was selected in vitro by stepwise exposure of C. jejuni NCTC11168(S) to increasing concentrations of erythromycin.The resistant were subjected to microarray and the the global transcriptional profile was analyzed. In this series, DNA microarray was used to compare the gene expression profiles of the macrolide-resistant strain with its parent wild-type strain NCTC11168. A large number of gene showed significant changes in R. The up-regulated genes in the resistant strains are involved in miscellaneous periplasmic proteins, efflux protein and putative aminotransferase, while the majority of the down-regulated genes are involved in electron transport, lipoprotein, heat shock protein and unknown function proteins. The over-expression of efflux pump and periplasmic protein was involved in the development of resistance to macrolide in C. jejuni. An eight chip study using total RNA recovered from four separate resistant-type cultures of Erythrocin-resistant Campylobacter jejuni NCTC111168 (R) and four separate cultures of Campylobacter jejuni NCTC111168 (S). Each chip measures the expression level of 1634 genes from Campylobacter jejuni NCTC11168.
Project description:For Streptococcus pneumoniae, biofilms have been suggested to promote long-term colonization of the nasopharynx and contribute to the pathology of recurrent middle ear infections. To date numerous studies have investigated the contribution of specific genetic determinants for the development of pneumococcal biofilms, however, studies examining the global changes that occur during biofilm development and how they contribute to disease are lacking. Using Scanning and Transmission electron microscopy we examined development of a mature pneumococcal biofilm in a continuous flow through reactor. We determined that a mature biofilm is formed in discrete stages, is marked by the formation of complex 3-dimensional structures, and is primarily composed of dead pneumococci. Using genomic microarrays we determined that pneumococci in mature biofilms down regulate genes involved in protein synthesis, energy production, metabolism, capsular polysaccharide production, and virulence. We confirmed these changes by testing bacterial resistance to antimicrobials, measuring capsule production by ELSIA, and immunoblotting for pneumolysin production. We determined that biofilm pneumococci are hyper-adhesive, binding to cell lines at levels 9 to 11-fold greater than planktonic counterparts. Using Western blot and ELISA, we determined that biofilm bacteria produce greater amounts of the adhesins PsrP, CbpA, and surface exposed phosphorylcholine. We subsequently determined that the hyper-adhesive phenotype was in part due to selection of the transparent phase variant during biofilm growth. Intranasal, intratracheal and intraperitoneal challenge of mice with biofilm and planktonic pneumococci determined that biofilm bacteria were highly attenuated for invasive disease but not nasopharyngeal colonization. Immunization of mice with ethanol-killed biofilm pneumococci of serotype 4 conferred protection against challenge with same isolate but not a serotype 3. ELISA for reactive IgG levels subsequently determined that biofilm pneumococci do not provide high levels of cross-reactive protein antigens. Together these studies suggest that biofilms do not directly contribute to disease but instead confer a protected mode of growth for the pneumococcus. Pneumococcal biofilms compared to planktonic control at 4, 12, 24, 48 hours. 3 biological replicates each of 4 and 12 hour time points, and 2 biological replicates each of 24 and 48 hour time points. Flip dye (technical replicates) performed for 4, 12, and 24 hour time points; no technical replicate performed for 48 hour time point due to limiting material. Ratios were determined by averaging across technical and biological replicates. The following hybridizations made up each biological replicate: 14090167.tav.annot and 14090190.tav.annot (4hr biol rep 1); 14090169.tav.annot and 14090176.tav.annot (4hr biol rep 2); 14090192.tav.annot and 14090188.tav.annot (4hr biol rep 3); 14087688.tav.annot and 14090180.tav.annot (12hr biol rep 1); 14090185.tav.annot and 14090168.tav.annot (12hr biol rep 2); 14090191.tav.annot and 14090174.tav.annot (12hr biol rep 3); 14090170.tav.annot and 14090175.tav.annot (24hr biol rep 2); 14090193.tav.annot and 14087687.tav.annot (24hr biol rep 3); 14090181.tav.annot (48hr biol rep 1); 14090187.tav.annot (48hr biol rep 2)
Project description:Campylobacter jejuni is one of the most important causes of food-borne diseases in industrialized countries. It is known that amino acids are important nutrient source for this pathogen, because C. jejuni lacks enzymes related to glycolysis. However, the characteristics on metabolism of C. jejuni grown in the nutrient restricted medium with a specific amino acid is not fully elucidated. This study shows that C. jejuni NCTC11168 grew well in the nutrient restricted medium containing serine, aspartate, glutamate, and proline. The single subtraction of serine significantly reduced the growth, while three other amino acids did not, suggesting the priority of serine among the four amino acids. In the transcriptomic analysis of C. jejuni NCTC11168 grown in medium with serine as a main energy source. Serine seemed to be sensed by some chemoreceptors and the C. jejuni might reached an adaptation stage with active growth. That is, the expression of flagellar assembly components was downregulated and the biosynthesis of multiple amino acids and nucleotide sugars were upregulated. These data suggest the higher requirement of serine as a nutrient of C. jejuni NCTC11168. Overall design: Serine induced gene expression in Campylobacter jejuni was measured at 8 hours after exposure to dose of 20mM.
Project description:Cj0440c encodes a putative transcriptional regulator. To determine the role of Cj0440c in C.jejuni, we knocked out Cj0440c in the wild-type strain (S) to obtain the Cj0440c mutants (SM). Then we compared the transcriptome of the Cj0440c mutant with that of the parent strain using DNA microarray. These comparisons identified 19 genes that showed a≥2-fold change in expression in SM. The differentially expressed genes in SM encode proteins involved in flagellar biosynthesis, O-linked glycosylation and hypothetical proteins with unknown fuctions. Cj0440c may regulate flagellar structural element expression or as a compenent of flagellar complex co-expressed with other flagellar genes. Subsequent experiments demonstrated that inactivation of Cj0440c affected corresponding phenotypes of C.jejuni, including broken flagella, weaker motility and reduced colonization ability in chickens. These findings indicate that Cj0440c governs the expression of multiple genes related to flagellar biosynthesis and O-linked glycosylation. This study provides favorable evidence for completing the information of the Campylobacter jejuni genome. An eight chip study using total RNA recoverd from four separate wild-type cultures of Campylobacter jejuni NCTC111168 (S) and four separate cultures of a mutant strain, Campylobacter jejuni NCTC11168 delta- Cj0440c (SM), in which Cj0440c is deleted. Each chip measures the expression level of 1634 genes from Campylobacter jejuni NCTC11168.
Project description:This study investigates the CsrA regulon of the food-borne pathogen Campylobacter jejuni. Direct RNA binding targets of CsrA in two strains of C. jejuni, NCTC11168 and 81-176, were determined using RIP-seq. Identification of CsrA binding sites in two C. jejuni strains using RIP-seq
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. Overall design: 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:Campylobacter jejuni is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. For pathogen control in the food industry, the use of natural antimicrobial molecules is a promising strategy to avoid antibiotic treatments. Isothiocyanates are natural antimicrobial compounds which also display anti-cancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood. We investigated the early cellular response of C. jejuni to benzylisothiocyanate (BITC) by both transcriptomic and physiological (respirometry, ATP content measurements and isolations of aggregated proteins). To characterize the transcriptomic early response to benzylisothiocyanate, C. jejuni NCTC11168 were grown in 100 ml flasks containing 25 ml of MEMα medium plus 20 mM sodium pyruvate. At mid-log phase, 2µg/mL benzylisothiocyanate in ethanol, or the same volume of ethanol (control) was added to the flasks for 10 or 15 min prior to total RNA extraction and purification. Samples were then processed for microarray hybridization. Microarray data was acquired from two (10 minutes assay) or three (15 minutes assay) independent biological replicates and 6 to 9 technical replicates for each biological replicate (total number of measurement per gene = 42).