Project description:Enterotoxin-producing C. perfringens type A is a common cause of food poisonings. The cpe encoding the enterotoxin can be chromosomal (genotype IS1470) or plasmid-borne (genotypes IS1470-like-cpe or IS1151-cpe). The chromosomal cpe-carrying C. perfringens are a more common cause of food poisonings than plasmid-borne cpe-genotypes. The chromosomal cpe-carrying C. perfringens type A strains are generally more resistant to most food-processing conditions than plasmid-borne cpe-carrying strains. On the other hand, the plasmid-borne cpe-positive genotypes are more commonly found in human feces than chromosomal cpe-positive genotypes, and humans seem to be a reservoir for plasmid-borne cpe-carrying strains. Thus, it is possible that the epidemiology of C. perfringes type A food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains is different. A DNA microarray was designed for analysis of genetic relatedness between the different cpe-positive and cpe-negative genotypes of C. perfringens strains isolated from human, animal, environmental and food samples. The DNA microarray contained two probes for all protein-coding sequences in the three genome-sequenced strains (C. perfringens type A strains 13, ATCC13124, and SM101). The chromosomal and plasmid-borne C. perfringens genotypes were grouped into two distinct clusters, one consisting of the chromosomal cpe-genotypes and the other consisting of plasmid-borne cpe-genotypes. Analysis of the variable gene pool complemented with the growth studies demonstrate different carbohydrate and amine metabolism in the chromosomal and plasmid-borne cpe-carrying strains, suggesting different epidemiology of the cpe-positive C. perfringens strain groups.
Project description:Enterotoxin-producing C. perfringens type A is a common cause of food poisonings. The cpe encoding the enterotoxin can be chromosomal (genotype IS1470) or plasmid-borne (genotypes IS1470-like-cpe or IS1151-cpe). The chromosomal cpe-carrying C. perfringens are a more common cause of food poisonings than plasmid-borne cpe-genotypes. The chromosomal cpe-carrying C. perfringens type A strains are generally more resistant to most food-processing conditions than plasmid-borne cpe-carrying strains. On the other hand, the plasmid-borne cpe-positive genotypes are more commonly found in human feces than chromosomal cpe-positive genotypes, and humans seem to be a reservoir for plasmid-borne cpe-carrying strains. Thus, it is possible that the epidemiology of C. perfringes type A food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains is different. A DNA microarray was designed for analysis of genetic relatedness between the different cpe-positive and cpe-negative genotypes of C. perfringens strains isolated from human, animal, environmental and food samples. The DNA microarray contained two probes for all protein-coding sequences in the three genome-sequenced strains (C. perfringens type A strains 13, ATCC13124, and SM101). The chromosomal and plasmid-borne C. perfringens genotypes were grouped into two distinct clusters, one consisting of the chromosomal cpe-genotypes and the other consisting of plasmid-borne cpe-genotypes. Analysis of the variable gene pool complemented with the growth studies demonstrate different carbohydrate and amine metabolism in the chromosomal and plasmid-borne cpe-carrying strains, suggesting different epidemiology of the cpe-positive C. perfringens strain groups. Array CGH. Two-color hybridizations on 8x15K Agilent arrays. Eight reference strain hybridizations. Normalization was based on log-ratios against the reference strain. For each sample, 8 normalization factors were calculated, one against each reference hybridization, and the median normalization factor was used. This was repeated for each sample hybridization separately.
Project description:Clostridium perfringens type A is a common source of food poisoning in humans. Vegetative cells sporulate in the small intestinal tract and produce a major pathogenic factor, C. perfringens enterotoxin (CPE) during sporulation. Although sporulation plays a critical role in the pathogenesis of food poisoning, the mechanisms to induce in vivo sporulation remain unclear. Bile salts had been identified to mediate sporulation, and we have confirmed deoxycholate (DCA)-induced sporulation in C. perfringens strain NCTC8239 co-cultured with human intestinal epithelial Caco-2 cells. In this study, we performed global transcriptome analysis of strain NCTC8239 to elucidate the mechanism to induce sporulation by DCA.
Project description:Clostridium perfringens type A is a common source of food poisoning in humans. Vegetative cells sporulate in the small intestinal tract and produce a major pathogenic factor, C. perfringens enterotoxin (CPE) during sporulation. Although sporulation plays a critical role in the pathogenesis of food poisoning, the mechanisms to induce in vivo sporulation remain unclear. Bile salts had been identified to mediate sporulation, and we have confirmed deoxycholate (DCA)-induced sporulation in C. perfringens strain NCTC8239 co-cultured with human intestinal epithelial Caco-2 cells. In this study, we performed global transcriptome analysis of strain NCTC8239 to elucidate the mechanism to induce sporulation by DCA. From the 55 contigs of C. perfringens strain NCTC8239, 2778 coding sequences were extracted. We designed a DNA probe by utilizing eArray provided by Agilent Technologies. The custom 8Ã15K oligonucleotide array, containing 60 mer oligonucleotide probes for 2,778 genes in strain NCTC8239, 2 bacterial control genes: 16S rRNA and 23S rRNA, and 3 human control genes: beta-2-microglobulin, glucuronidase beta and 18S rRNA, were ordered to Agilent Technologies. Each probe was spotted in five-fold on each microarray. Each strain was run in triplicate or quadruplicate.
Project description:Clostridium perfringens is an anaerobic, gram-positive, spore-forming bacterium spread throughout the environment. This bacterium is a common agent in the gastrointestinal tracts of healthy human beings and other mammals. Simultaneously, this agent is one of the most significant producers of toxins among all known bacteria. This expressive toxicity is due to the bacterium’s ability collectively to produce different protein toxins and/or enzymes with diverse modes of action. The present study uses currently developed targeted proteomic methods for the simultaneous detection of selected C. perfringens protein toxins. The method was applied in different kinds of environmental matrices and was used to analyze toxins production in a set of collection strains.
Project description:In this study we focus on the identification of new genes tentatively involved in sporulation and those that influence properties of spores and their ability to germinate. To this end, the sporulation stages of C. perfringens enterotoxic strain SM101 were characterized based on morphological characteristics and biological indicators. Subsequently, whole genome expression profiling during key stages of the sporulation process was performed using DNA microarrays, and genes were clustered based on their time-course expression profiles during sporulation. The majority of previously characterized C. perfringens germination genes showed upregulated expression profiles in time during sporulation and mainly belonged to two clusters of genes.
Project description:RevR is a putative orphan response regulator with a high degree of similarity to YycF from Bacilus subtilis and PhoB from Clostridium kluyveri. A revR deletion mutant of C. perfringens strain 13 was generated and the transcriptome analysed using microarrays.
Project description:Comparative genomic hybridization analysis shows different epidemiology of chromosomal and plasmid-borne cpe-carrying Clostridium perfringens type A strains
Project description:We further characterize the VirSR and RevR regulatory networks by profiling the C. perfringens strain JIR325 and its isogenic virR and revR regulatory mutants using strand-specific RNA-seq. Two independent biological replicates were sequenced for each strain, generating more than 90 million sequence reads for each RNA-seq library (wild type, 97,289,148 reads; virR mutant, 116,505,992 reads and revR mutant, 131,811,486 reads). Using the edgeR analysis package, 223 genes in the virR mutant and 88 genes in the revR mutant were found to be differentially expressed. Comparative transcriptomic analysis revealed that VirR acts as a global negative regulator, whilst RevR acts as a global positive regulator. Therefore, about 88% of the differentially expressed genes were up-regulated in the virR mutant, whereas 75% of the differentially expressed genes were down-regulated in the revR mutant. Importantly, we identified 22 genes that were regulated by both VirR and RevR. Of these genes, 18 or 82%, which included the sporulation-specific spoIVA, sigG and sigF genes, were regulated positively and negatively by RevR and VirR, respectively. Furthermore, mapped RNA-seq reads visualized as a user plot showed that there were 97 previously unannotated transcripts in the intergenic regions. These transcripts may potentially encode novel genes or small RNA molecules. This study has identified genes, antisense transcripts, and transcripts within intergenic regions and on the native plasmid, which are controlled by the VirSR or RevR regulatory system. The knowledge obtained will enable a more thorough annotation of the C. perfringens genome.