Updates on the sporulation process in Clostridium species

Talukdar, Prabhat K.; Olguín-Araneda, Valeria; Alnoman, Maryam M.; Paredes-Sabja, Daniel; Sarker, Mahfuzur R.

doi:10.1016/j.resmic.2014.12.001

Cited by 47 publications

(45 citation statements)

References 110 publications

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“…The expression of genes encoding histidine kinases was previously reported to be induced at the beginning of sporulation in B. subtilis (33,72). Although the orthologs of these kinases are not conserved in clostridia, histidine kinases directly activated the Spo0A protein and induced sporulation in several clostridia (34)(35)(36). Thus, we focused on the gene expression of orphan histidine kinases in our microarray analysis.…”

Section: Discussionmentioning

confidence: 99%

“…of Spo0A (34)(35)(36). In order to determine which orphan kinases are essential for Spo0A phosphorylation, we identified 8 orphan histidine kinases from 2,778 coding sequences in NCTC8239 based on blastp analyses with kinases from C. perfringens strains 13 and SM101 (35).…”

Section: Figmentioning

confidence: 99%

“…In order to determine which orphan kinases are essential for Spo0A phosphorylation, we identified 8 orphan histidine kinases from 2,778 coding sequences in NCTC8239 based on blastp analyses with kinases from C. perfringens strains 13 and SM101 (35). We then examined their expression profiles in our microarray data sets because the expression of genes encoding histidine kinases was induced at the beginning of sporulation in B. subtilis (33,72).…”

Section: Figmentioning

confidence: 99%

“…For example, the genes for Spo0F and Spo0B involved in the Spo0A phosphorelay system in Bacillus spp. are hardly conserved in clostridia (33); thus, Spo0A appears to be directly phosphorylated by histidine kinases in several clostridia (34)(35)(36). The conserved gene products involved in sporulation, such as oligopeptide permeases, have different functions in bacilli and clostridia (37).…”

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confidence: 99%

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Transcriptional Profile during Deoxycholate-Induced Sporulation in a Clostridium perfringens Isolate Causing Foodborne Illness

Yasugi

Okuzaki

Kuwana

et al. 2016

Appl Environ Microbiol

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Clostridium perfringens type A is a common source of foodborne illness (FBI) in humans. Vegetative cells sporulate in the small intestinal tract and produce the major pathogenic factor C. perfringens enterotoxin. Although sporulation plays a critical role in the pathogenesis of FBI, the mechanisms inducing sporulation remain unclear. Bile salts were shown previously to induce sporulation, and we confirmed deoxycholate (DCA)-induced sporulation in C. perfringens strain NCTC8239 cocultured with human intestinal epithelial Caco-2 cells. In the present study, we performed transcriptome analyses of strain NCTC8239 in order to elucidate the mechanism underlying DCA-induced sporulation. Of the 2,761 genes analyzed, 333 were up-or downregulated during DCA-induced sporulation and included genes for cell division, nutrient metabolism, signal transduction, and defense mechanisms. In contrast, the virulence-associated transcriptional regulators (the VirR/VirS system, the agr system, codY, and abrB) were not activated by DCA. DCA markedly increased the expression of signaling molecules controlled by Spo0A, the master regulator of the sporulation process, whereas the expression of spo0A itself was not altered in the presence or absence of DCA. The phosphorylation of Spo0A was enhanced in the presence of DCA. Collectively, these results demonstrated that DCA induced sporulation, at least partially, by facilitating the phosphorylation of Spo0A and activating Spo0A-regulated genes in strain NCTC8239 while altering the expression of various genes. IMPORTANCEDisease caused by Clostridium perfringens type A consistently ranks among the most common bacterial foodborne illnesses in humans in developed countries. The sporulation of C. perfringens in the small intestinal tract is a key event for its pathogenesis, but the factors and underlying mechanisms by which C. perfringens sporulates in vivo currently remain unclear. Bile salts, major components of bile, which is secreted from the liver for the emulsification of lipids, were shown to induce sporulation. However, the mechanisms underlying bile salt-induced sporulation have not yet been clarified. In the present study, we demonstrate that deoxycholate (one of the bile salts) induces sporulation by facilitating the phosphorylation of Spo0A and activating Spo0A-regulated genes using a transcriptome analysis. Thus, this study enhances our understanding of the mechanisms underlying sporulation, particularly that of bile salt-induced sporulation, in C. perfringens. C lostridium perfringens, a Gram-positive spore-forming anaerobic bacterium, is highly prevalent in the intestinal tracts of humans and animals and also in nature, such as in soil, sewage, and rivers (1, 2). This bacterium has been identified as a major pathogen in foodborne illness (FBI) and consistently ranks among the most common bacterial FBI in the United States, United Kingdom, and Japan (1, 3, 4). Therefore, controlling this FBI is a critical issue from a public health perspective. FBI occurs when contaminated f...

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Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

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Transcriptional Profile during Deoxycholate-Induced Sporulation in a Clostridium perfringens Isolate Causing Foodborne Illness

Yasugi

Okuzaki

Kuwana

et al. 2016

Appl Environ Microbiol

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“… and are being clarified in Clostridium spp. . Entry into the sporulation pathway is governed by Spo0A, a member of the response regulator family.…”

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confidence: 99%

Nitrate salts suppress sporulation and production of enterotoxin in Clostridium perfringens strain NCTC8239

Yasugi

Otsuka

Miyake

2016

Microbiology and Immunology

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Clostridium perfringens type A is a common source of food-borne illness in humans. Ingested vegetative cells sporulate in the small intestinal tract and in the process produce C. perfringens enterotoxin (CPE). Although sporulation plays a critical role in the pathogenesis of food-borne illness, the molecules triggering/inhibiting sporulation are still largely unknown. It has previously been reported by our group that sporulation is induced in C. perfringens strain NCTC8239 co-cultured with Caco-2 cells in Dulbecco's Modified Eagle Medium (DMEM). In contrast, an equivalent amount of spores was not observed when bacteria were co-cultured in Roswell Park Memorial Institute-1640 medium (RPMI). In the present study it was found that, when these two media are mixed, RPMI inhibits sporulation and CPE production induced in DMEM. When a component of RPMI was added to DMEM, it was found that calcium nitrate (Ca[NO ] ) significantly inhibits sporulation and CPE production. The number of spores increased when Ca(NO ) -deficient RPMI was used. The other nitrate salts significantly suppressed sporulation, whereas the calcium salts used did not. qPCR revealed that nitrate salts increased expression of bacterial nitrate/nitrite reductase. Furthermore, it was found that nitrite and nitric oxide suppress sporulation. In the sporulation stages, Ca(NO ) down-regulated the genes controlled by Spo0A, a master regulator of sporulation, but not spo0A itself. Collectively, these results indicate that nitrate salts suppress sporulation and CPE production by down-regulating Spo0A-regulated genes in C. perfringens strain NCTC8239. Nitrate reduction may be associated with inhibition of sporulation.

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