Physiology of Sporulation of Clostridia

Labbé, Ronald G.; Shih, N-J Remi

doi:10.1016/b978-012595020-6/50004-8

Cited by 8 publications

(9 citation statements)

References 67 publications

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“…The intrinsic P i concentration (Ͻ2 mM) in TGY and FTG medium was lower than the threshold P i concentration (5 to 7 mM) needed to induce spore formation (Table 1). In addition, both media contain high levels of glucose (0.55% and 2.0% for FTG and TGY, respectively) that would induce catabolite repression of sporulation as previously reported (13,26). In fact, the use of glucose (1%) in DSMM supplemented with 35 mM P i resulted in a noticeable inhibition of spore formation (data not shown).…”

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confidence: 81%

“…The copious amount of CPE (as much as 10% or more of the total protein of the developing sporangium) is accumulated probably only in the cytoplasm of the mother cell compartment until its release when the mother cell lyses at the completion of sporulation to liberate the mature spore (17). The released CPE rapidly binds to protein receptors present on the apical surface of enterocytes and induces cell permeabilization with the concomitant appearance of the symptoms of enterotoxaemia, intestinal cramping, and diarrhea (2,17,18).Despite the key role of spores in CPE synthesis and in the dissemination and developing of clostridial diseases, very little is known at the molecular level about the regulatory mechanisms governing the formation of spores in clostridia (6,9,11,13,20,23). Although from genome sequence analyses it can be assumed that the mechanism of spore formation in Bacillus and Clostridium is conserved (21,24,25), the main differences reside at the level of the initiation of the sporulation process (24, 25).…”

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confidence: 99%

“…Despite the key role of spores in CPE synthesis and in the dissemination and developing of clostridial diseases, very little is known at the molecular level about the regulatory mechanisms governing the formation of spores in clostridia (6,9,11,13,20,23). Although from genome sequence analyses it can be assumed that the mechanism of spore formation in Bacillus and Clostridium is conserved (21,24,25), the main differences reside at the level of the initiation of the sporulation process (24, 25).…”

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Inorganic Phosphate Induces Spore Morphogenesis and Enterotoxin Production in the Intestinal Pathogen Clostridium perfringens

et al. 2006

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Clostridium perfringens enterotoxin (CPE) is an important virulence factor for food poisoning and non-food borne gastrointestinal (GI) diseases. Although CPE production is strongly regulated by sporulation, the nature of the signal(s) triggering sporulation remains unknown. Here, we demonstrated that inorganic phosphate (P i ), and not pH, constitutes an environmental signal inducing sporulation and CPE synthesis. In the absence of P i -supplementation, C. perfringens displayed a spo0A phenotype, i.e., absence of polar septation and DNA partitioning in cells that reached the stationary phase of growth. These results received support from our Northern blot analyses which demonstrated that P i was able to counteract the inhibitory effect of glucose at the onset of sporulation and induced spo0A expression, indicating that P i acts as a key signal triggering spore morphogenesis. In addition to being the first study reporting the nature of a physiological signal triggering sporulation in clostridia, these findings have relevance for the development of antisporulation drugs to prevent or treat CPE-mediated GI diseases in humans.Clostridium perfringens is a gram-positive, anaerobic, endospore-forming bacterium causing gastrointestinal and histotoxic infections in humans and animals (2, 6, 9, 17). The virulence of this bacterium largely results from its prolific ability to produce at least 15 different toxins (18). In addition, enterotoxigenic C. perfringens isolates produce a 35-kDa enterotoxin (C. perfringens enterotoxin [CPE]), whose synthesis is under a strict positive control of sporulation (3,5,6,9,17). In C. perfringens, the production of CPE is confined to the large compartment (mother cell) of the sporangium where cpe transcription is believed to be driven from the mother cell-specific forms of the RNA polymerase, RNA-E and RNA-K (30). The copious amount of CPE (as much as 10% or more of the total protein of the developing sporangium) is accumulated probably only in the cytoplasm of the mother cell compartment until its release when the mother cell lyses at the completion of sporulation to liberate the mature spore (17). The released CPE rapidly binds to protein receptors present on the apical surface of enterocytes and induces cell permeabilization with the concomitant appearance of the symptoms of enterotoxaemia, intestinal cramping, and diarrhea (2,17,18).Despite the key role of spores in CPE synthesis and in the dissemination and developing of clostridial diseases, very little is known at the molecular level about the regulatory mechanisms governing the formation of spores in clostridia (6,9,11,13,20,23). Although from genome sequence analyses it can be assumed that the mechanism of spore formation in Bacillus and Clostridium is conserved (21,24,25), the main differences reside at the level of the initiation of the sporulation process (24, 25). While orthologs for spo0A and the genes activated by Spo0AϳP, along with most of the spo genes that are subsequently expressed during the morphogenesis of the spore,...

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confidence: 99%

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Inorganic Phosphate Induces Spore Morphogenesis and Enterotoxin Production in the Intestinal Pathogen Clostridium perfringens

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“…The sporulation medium we used in these experiments, DSSM, contains ϳ8 mM raffinose. Typically, C. perfringens sporulation media, including DSSM, contain moderate amounts of nutrient-rich ingredients (e.g., proteose peptone and yeast extract) in combination with a slowly utilizable carbohydrate source (e.g., starch or raffinose) (26)(27)(28)(29)45). Therefore, carbohydrate metabolism appears to be an important part of the initiation and/or completion of sporulation by C. perfringens.…”

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confidence: 99%

“…Glucose has been shown to act as a catabolite repressor of sporulation in C. perfringens (29,45). The mechanism of catabolite repression of sporulation by glucose in C. perfringens has not been determined, but in Bacillus subtilis, another gram-positive spore-forming bacterium, many catabolite repressor (CR) effects from glucose, including sporulation, have been shown to be mediated by the transcriptional regulator CcpA, a member of the LacI/GalR family of repressor proteins (11,20).…”

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The CcpA Protein Is Necessary for Efficient Sporulation and Enterotoxin Gene (cpe) Regulation inClostridium perfringens

2004

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Clostridium perfringens is the cause of several human diseases, including gas gangrene (clostridial myonecrosis), enteritis necroticans, antibiotic-associated diarrhea, and acute food poisoning. The symptoms of antibiotic-associated diarrhea and acute food poisoning are due to sporulation-dependent production of C. perfringens enterotoxin encoded by the cpe gene. Glucose is a catabolite repressor of sporulation by C. perfringens. In order to identify the mechanism of catabolite repression by glucose, a mutation was introduced into the ccpA gene of C. perfringens by conjugational transfer of a nonreplicating plasmid into C. perfringens, which led to inactivation of the ccpA gene by homologous recombination. CcpA is a transcriptional regulator known to mediate catabolite repression in a number of low-G؉C-content gram-positive bacteria, of which C. perfringens is a member. The ccpA mutant strain sporulated at a 60-fold lower efficiency than the wild-type strain in the absence of glucose. In the presence of 5 mM glucose, sporulation was repressed about 2,000-fold in the wild-type strain and 800-fold in the ccpA mutant strain compared to sporulation levels for the same strains grown in the absence of glucose. Therefore, while CcpA is necessary for efficient sporulation in C. perfringens, glucose-mediated catabolite repression of sporulation is not due to the activity of CcpA. Transcription of the cpe gene was measured in the wild-type and ccpA mutant strains grown in sporulation medium by using a cpe-gusA fusion (gusA is an Escherichia coli gene encoding the enzyme ␤-glucuronidase). In the exponential growth phase, cpe transcription was two times higher in the ccpA mutant strain than in the wild-type strain. Transcription of cpe was highly induced during the entry into stationary phase in wild-type cells but was not induced in the ccpA mutant strain. Glucose repressed cpe transcription in both the wild-type and ccpA mutant strain. Therefore, CcpA appears to act as a repressor of cpe transcription in exponential growth but is required for efficient sporulation and cpe transcription upon entry into stationary phase. CcpA was also required for maximum synthesis of collagenase (kappa toxin) and acted as a repressor of polysaccharide capsule synthesis in the presence of glucose, but it did not regulate synthesis of the phospholipase PLC (alpha toxin).

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General Biology and Physiology

Mitchell

2001

Clostridia

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Physiology of Sporulation of Clostridia

Cited by 8 publications

References 67 publications

Inorganic Phosphate Induces Spore Morphogenesis and Enterotoxin Production in the Intestinal Pathogen Clostridium perfringens

Inorganic Phosphate Induces Spore Morphogenesis and Enterotoxin Production in the Intestinal Pathogen Clostridium perfringens

The CcpA Protein Is Necessary for Efficient Sporulation and Enterotoxin Gene (cpe) Regulation inClostridium perfringens

General Biology and Physiology

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