Use of CGH microarrays to identify strain variable genomic regions in C. botulinum ATCC 3502
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ABSTRACT: Comparative genomic hybridization microarrays featuring overlapping probes spanning the entire C. botulinum type A1 strain ATCC 3502 genome were used to identify regions whose presence are variable among a diverse panel of type A C. botulinum strains. For each hybridization, the reference strain (C. botulinum ATCC 3502) was labeled with Cy5 and test strains were labeled with Cy3.
Project description:Comparative genomic hybridizations were performed to compare bont/A1 strains with an A2-like toxin gene cluster organization to the genome sequenced strain, C. botulinum ATCC 3502. Keywords: comparative genomic hybridization For each hybridization, the reference strain (C. botulinum ATCC 3502) was labeled with Cy5 and each test strain was labeled with Cy3.
Project description:C. botulinum UMASS Type A strain was compared to the ATCC 3502 Type A reference strain. Genomic DNA from the UMASS Type A strain was labled with Cy3 and cohybridzied with Cy5 labeled genomic DNA isolated from the ATCC 3502 Type A strain using a custom comparative genomic hybridization microarray. Differences in gene content between the were assessed by examining the log2 ratio data of the signal intensities.
Project description:Strains were differentiated on the basis of hybridization to probes representing strain variable regions in C. botulinum strain ATCC 3502. Probes for selected genes (eg. toxin genes) were also featured on the microarray to allow detection of other serotypes/subtypes. 44 strains were evaluated for selected gene detection and/or strain differentiation. DNA from strain ATCC 3502 was used as a control as the featured probes were based on the ATCC 3502 genome sequence.
Project description:Strains were differentiated on the basis of hybridization to probes representing strain variable regions in C. botulinum strain ATCC 3502. Probes for selected genes (eg. toxin genes) were also featured on the microarray to allow detection of other serotypes/subtypes. 27 strains were evaluated for selected gene detection and/or strain differentiation. DNA from strain ATCC 3502 was used as a control as the featured probes were based on the ATCC 3502 genome sequence.
Project description:Comparative genomic hybridization microarrays featuring overlapping probes spanning the entire C. botulinum type A1 strain ATCC 3502 genome were used to identify regions whose presence are variable among a diverse panel of type A C. botulinum strains.
Project description:Profound understanding of the mechanisms foodborne pathogenic bacteria utilize in adaptation to the environmental stress they encounter during food processing and storage is of paramount importance in design of control measures. Chill temperature is a central control measure applied in minimally processed foods; however, data on the mechanisms the foodborne pathogen Clostridium botulinum activates upon cold stress are scarce. Global gene expression analysis on the C.M-BM- botulinum ATCC 3502 strain upon temperature downshift from 37 M-BM-0C to 15M-BM- M-BM-0C was performed to identify the cold-responsive gene set of this organism. Significant up- or down-regulation of 16 and 11 genes, respectively, was observed already 1 h after the cold shock. At 5 h after the temperature downshift, 199 and 210 genes were up- and down-regulated, respectively. Thus, the cold shock rapidly affected the expression of a gene set of a relatively small size, indicating a targeted acute response to cold shock, whereas extensive metabolic remodeling took place after prolonged exposure to cold. Induction of genes related to fatty acid biosynthesis, oxidative stress response, and iron uptake and storage was observed, in addition to mechanisms previously characterized as cold-tolerance related in bacteria. Furthermore, induction of several uncharacterized DNA-binding transcriptional regulator-encoding genes was observed, suggesting involvement of novel regulatory mechanisms in the cold shock response of C.M-BM- botulinum. The role of such regulatory proteins, CBO0477 and CBO0558A, in cold tolerance of C.M-BM- botulinum ATCC 3502 was demonstrated by the deteriorated growth of mutants of the respective genes at 17M-BM- M-BM-0C. C. botulinum ATCC 3502 wild type cold-shocked vs. pre-cold-shock; 3 replicates; growth at 37C in TPGY broth batch culture and subjected to cold shock to 15C; sampling at mid-log growth phase before cold shock, and 1 h and 5 h after temperature downshift to 15C (= 3 time points). Dye-swapped hybridization.
Project description:The two-component system CBO0366/CBO0365 was recently demonstrated to have a role in cold tolerance of Group I Clostridium botulinum ATCC 3502. The mechanisms under its control, ultimately resulting in increased sensitivity to low temperature, are unknown. A transcriptomic analysis with DNA microarrays was performed to identify the differences in global gene expression patterns of the wild-type ATCC 3502 and a derivative mutant with insertionally inactivated cbo0365 at 37 M-BM-0C and 15 M-BM-0C. Altogether 150 or 141 chromosomal CDSs were found to be differently expressed in the cbo0365 mutant at 37 M-BM-0C or 15 M-BM-0C, respectively, and thus considered to be under direct or indirect transcriptional control of the response regulator CBO0365. Of the differentially-expressed CDSs, expression of 141 CDSs was similarly affected at both temperatures investigated, suggesting that the putative CBO0365 regulon was practically not affected by temperature. The regulon involved genes related to acetone-butanol-ethanol (ABE) fermentation, motility, to arsenic resistance, and phosphate uptake and transport. Deteriorated growth at 17 M-BM-0C was observed for mutants with disrupted ABE fermentation pathway components (crt, bdh and ctfA), arsenic detoxifying machinery components (arsC and arsR), or phosphate uptake mechanism components (phoT), suggesting roles for these mechanisms in cold tolerance of Group I C. botulinum. Electrophoretic mobility shift assays showed recombinant CBO0365 to bind to the promoter regions of crt, arsR, and phoT, as well as to the promoter region of its own operon, suggesting direct DNA-binding transcriptional activation or repression as means for CBO0365 in regulating these operons. The results provide insight to the mechanisms Group I C. botulinum utilize in coping with cold. C. botulinum ATCC 3502 cbo0365 mutant vs. wild type; 3 replicates of each strain; growth at 37C in TPGY broth batch culture and subjected to cold shock to 15C; sampling at mid-log growth phase before cold shock, and 1 h after temperature downshift to 15C (= 2 time points). Dye-swapped hybridization.
Project description:Comparative genomic hybridizations were performed to compare bont/A1 strains with an A2-like toxin gene cluster organization to the genome sequenced strain, C. botulinum ATCC 3502. Keywords: comparative genomic hybridization
Project description:Clostridium botulinum is a heterogeneous Gram-positive species that comprises four genetically and physiologically distinct groups of bacteria that share the ability to produce botulinum neurotoxin, the most poisonous toxin known to man, and the causative agent of botulism, a severe disease of humans and animals. We report here the complete genome sequence of a representative of Group I (proteolytic) C. botulinum (strain Hall A, ATCC 3502). The genome consists of a chromosome (3,886,916 bp) and a plasmid (16,344 bp) which carry 3,650 and 19 predicted genes, respectively. Consistent with the proteolytic phenotype of this strain, the genome harbours a large number of genes encoding secreted proteases and enzymes involved in uptake and metabolism of amino acids. The genome also reveals a hitherto unknown ability of C. botulinum to degrade chitin. There is a significant lack of recently acquired DNA, indicating a stable genomic content, in strong contrast to the fluid genome of C. difficile, which can form longer-term relationships with its host. Overall, the genome indicates that C. botulinum is adapted to a saprophytic lifestyle both in soil and aquatic environments. This pathogen relies on its toxin to rapidly kill a wide range of prey species, and to gain access to nutrient sources, it releases a large number of extracellular enzymes to soften and destroy rotting or decayed tissues.