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1

Clostridium perfringens Epsilon Toxin: A Malevolent Molecule for Animals and Man?  

PubMed Central

Clostridium perfringens is a prolific, toxin-producing anaerobe causing multiple diseases in humans and animals. One of these toxins is epsilon, a 33 kDa protein produced by Clostridium perfringens (types B and D) that induces fatal enteric disease of goats, sheep and cattle. Epsilon toxin (Etx) belongs to the aerolysin-like toxin family. It contains three distinct domains, is proteolytically-activated and forms oligomeric pores on cell surfaces via a lipid raft-associated protein(s). Vaccination controls Etx-induced disease in the field. However, therapeutic measures are currently lacking. This review initially introduces C. perfringens toxins, subsequently focusing upon the Etx and its biochemistry, disease characteristics in various animals that include laboratory models (in vitro and in vivo), and finally control mechanisms (vaccines and therapeutics). PMID:24284826

Stiles, Bradley G.; Barth, Gillian; Barth, Holger; Popoff, Michel R.

2013-01-01

2

Clostridium perfringens Epsilon Toxin Increases the Small Intestinal Permeability in Mice and Rats  

PubMed Central

Epsilon toxin is a potent neurotoxin produced by Clostridium perfringens types B and D, an anaerobic bacterium that causes enterotoxaemia in ruminants. In the affected animal, it causes oedema of the lungs and brain by damaging the endothelial cells, inducing physiological and morphological changes. Although it is believed to compromise the intestinal barrier, thus entering the gut vasculature, little is known about the mechanism underlying this process. This study characterizes the effects of epsilon toxin on fluid transport and bioelectrical parameters in the small intestine of mice and rats. The enteropooling and the intestinal loop tests, together with the single-pass perfusion assay and in vitro and ex vivo analysis in Ussing's chamber, were all used in combination with histological and ultrastructural analysis of mice and rat small intestine, challenged with or without C. perfringens epsilon toxin. Luminal epsilon toxin induced a time and concentration dependent intestinal fluid accumulation and fall of the transepithelial resistance. Although no evident histological changes were observed, opening of the mucosa tight junction in combination with apoptotic changes in the lamina propria were seen with transmission electron microscopy. These results indicate that C. perfringens epsilon toxin alters the intestinal permeability, predominantly by opening the mucosa tight junction, increasing its permeability to macromolecules, and inducing further degenerative changes in the lamina propria of the bowel. PMID:19763257

Goldstein, Jorge; Morris, Winston E.; Loidl, Cesar Fabian; Tironi-Farinatti, Carla; McClane, Bruce A.; Uzal, Francisco A.; Fernandez Miyakawa, Mariano E.

2009-01-01

3

Proteolytic Processing and Activation of Clostridium perfringens Epsilon Toxin by Caprine Small Intestinal Contents  

PubMed Central

ABSTRACT Epsilon toxin (ETX), a pore-forming toxin produced by type B and D strains of Clostridium perfringens, mediates severe enterotoxemia in livestock and possibly plays a role in human disease. During enterotoxemia, the nearly inactive ETX prototoxin is produced in the intestines but then must be activated by proteolytic processing. The current study sought to examine ETX prototoxin processing and activation ex vivo using the intestinal contents of a goat, a natural host species for ETX-mediated disease. First, this study showed that the prototoxin has a KEIS N-terminal sequence with a molecular mass of 33,054 Da. When the activation of ETX prototoxin ex vivo by goat small intestinal contents was assessed by SDS-PAGE, the prototoxin was processed in a stepwise fashion into an ~27-kDa band or higher-molecular-mass material that could be toxin oligomers. Purified ETX corresponding to the ~27-kDa band was cytotoxic. When it was biochemically characterized by mass spectrometry, the copresence of three ETX species, each with different C-terminal residues, was identified in the purified ~27-kDa ETX preparation. Cytotoxicity of each of the three ETX species was then demonstrated using recombinant DNA approaches. Serine protease inhibitors blocked the initial proteotoxin processing, while carboxypeptidase inhibitors blocked further processing events. Taken together, this study provides important new insights indicating that, in the intestinal lumen, serine protease (including trypsin and possibly chymotrypsin) initiates the processing of the prototoxin but other proteases, including carboxypeptidases, then process the prototoxin into multiple active and stable species. PMID:25336460

Freedman, John C.; Li, Jihong; Uzal, Francisco A.

2014-01-01

4

Proteolytic processing and activation of Clostridium perfringens epsilon toxin by caprine small intestinal contents.  

PubMed

Epsilon toxin (ETX), a pore-forming toxin produced by type B and D strains of Clostridium perfringens, mediates severe enterotoxemia in livestock and possibly plays a role in human disease. During enterotoxemia, the nearly inactive ETX prototoxin is produced in the intestines but then must be activated by proteolytic processing. The current study sought to examine ETX prototoxin processing and activation ex vivo using the intestinal contents of a goat, a natural host species for ETX-mediated disease. First, this study showed that the prototoxin has a KEIS N-terminal sequence with a molecular mass of 33,054 Da. When the activation of ETX prototoxin ex vivo by goat small intestinal contents was assessed by SDS-PAGE, the prototoxin was processed in a stepwise fashion into an ~27-kDa band or higher-molecular-mass material that could be toxin oligomers. Purified ETX corresponding to the ~27-kDa band was cytotoxic. When it was biochemically characterized by mass spectrometry, the copresence of three ETX species, each with different C-terminal residues, was identified in the purified ~27-kDa ETX preparation. Cytotoxicity of each of the three ETX species was then demonstrated using recombinant DNA approaches. Serine protease inhibitors blocked the initial proteotoxin processing, while carboxypeptidase inhibitors blocked further processing events. Taken together, this study provides important new insights indicating that, in the intestinal lumen, serine protease (including trypsin and possibly chymotrypsin) initiates the processing of the prototoxin but other proteases, including carboxypeptidases, then process the prototoxin into multiple active and stable species. Importance: Processing and activation by intestinal proteases is a prerequisite for ETX-induced toxicity. Previous studies had characterized the activation of ETX using only arbitrarily chosen amounts of purified trypsin and/or chymotrypsin. Therefore, the current study examined ETX activation ex vivo by natural host intestinal contents. These analyses demonstrated that (i) ETX processing in host intestinal contents occurs in an ordered, stepwise fashion, (ii) processing of prototoxin by host intestinal contents results in higher-molecular-mass material and 3 distinct ~27-kDa ETX species, and (iii) serine proteases, such as trypsin, chymotrypsin, and other proteases, including carboxypeptidases, play a role in the activation of ETX by intestinal contents. These studies provide new insights into the activation and processing of ETX and demonstrate that this process is more complicated than previously appreciated. PMID:25336460

Freedman, John C; Li, Jihong; Uzal, Francisco A; McClane, Bruce A

2014-01-01

5

Oligomerization of Clostridium perfringens Epsilon Toxin Is Dependent upon Caveolins 1 and 2  

PubMed Central

Evidence from multiple studies suggests that Clostridium perfringens ?-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2). In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1), in ?-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ?-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ?-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ?-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ?-toxin induced cytotoxicity by promoting toxin oligomerization – an event which is requisite for pore formation and, by extension, cell death. PMID:23056496

Fennessey, Christine M.; Sheng, Jinsong; Rubin, Donald H.; McClain, Mark S.

2012-01-01

6

Clostridium perfringens epsilon toxin mutant Y30A-Y196A as a recombinant vaccine candidate against enterotoxemia.  

PubMed

Epsilon toxin (Etx) is a ?-pore-forming toxin produced by Clostridium perfringens toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe, often fatal disease of ruminants that causes significant economic losses to the farming industry worldwide. This study aimed to determine the potential of a site-directed mutant of Etx (Y30A-Y196A) to be exploited as a recombinant vaccine against enterotoxemia. Replacement of Y30 and Y196 with alanine generated a stable variant of Etx with significantly reduced cell binding and cytotoxic activities in MDCK.2 cells relative to wild type toxin (>430-fold increase in CT50) and Y30A-Y196A was inactive in mice after intraperitoneal administration of trypsin activated toxin at 1000× the expected LD50 dose of trypsin activated wild type toxin. Moreover, polyclonal antibody raised in rabbits against Y30A-Y196A provided protection against wild type toxin in an in vitro neutralisation assay. These data suggest that Y30A-Y196A mutant could form the basis of an improved recombinant vaccine against enterotoxemia. PMID:24709588

Bokori-Brown, Monika; Hall, Charlotte A; Vance, Charlotte; Fernandes da Costa, Sérgio P; Savva, Christos G; Naylor, Claire E; Cole, Ambrose R; Basak, Ajit K; Moss, David S; Titball, Richard W

2014-05-13

7

Clostridium perfringens epsilon toxin mutant Y30A-Y196A as a recombinant vaccine candidate against enterotoxemia  

PubMed Central

Epsilon toxin (Etx) is a ?-pore-forming toxin produced by Clostridium perfringens toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe, often fatal disease of ruminants that causes significant economic losses to the farming industry worldwide. This study aimed to determine the potential of a site-directed mutant of Etx (Y30A-Y196A) to be exploited as a recombinant vaccine against enterotoxemia. Replacement of Y30 and Y196 with alanine generated a stable variant of Etx with significantly reduced cell binding and cytotoxic activities in MDCK.2 cells relative to wild type toxin (>430-fold increase in CT50) and Y30A-Y196A was inactive in mice after intraperitoneal administration of trypsin activated toxin at 1000× the expected LD50 dose of trypsin activated wild type toxin. Moreover, polyclonal antibody raised in rabbits against Y30A-Y196A provided protection against wild type toxin in an in vitro neutralisation assay. These data suggest that Y30A-Y196A mutant could form the basis of an improved recombinant vaccine against enterotoxemia. PMID:24709588

Bokori-Brown, Monika; Hall, Charlotte A.; Vance, Charlotte; Fernandes da Costa, Sergio P.; Savva, Christos G.; Naylor, Claire E.; Cole, Ambrose R.; Basak, Ajit K.; Moss, David S.; Titball, Richard W.

2014-01-01

8

Correlation between In Vitro Cytotoxicity and In Vivo Lethal Activity in Mice of Epsilon Toxin Mutants from Clostridium perfringens  

PubMed Central

Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein with a lethal effect on livestock, producing severe enterotoxemia characterized by general edema and neurological alterations. Site-specific mutations of the toxin are valuable tools to study the cellular and molecular mechanism of the toxin activity. In particular, mutants with paired cysteine substitutions that affect the membrane insertion domain behaved as dominant-negative inhibitors of toxin activity in MDCK cells. We produced similar mutants, together with a well-known non-toxic mutant (Etx-H106P), as green fluorescent protein (GFP) fusion proteins to perform in vivo studies in an acutely intoxicated mouse model. The mutant (GFP-Etx-I51C/A114C) had a lethal effect with generalized edema, and accumulated in the brain parenchyma due to its ability to cross the blood-brain barrier (BBB). In the renal system, this mutant had a cytotoxic effect on distal tubule epithelial cells. The other mutants studied (GFP-Etx-V56C/F118C and GFP-Etx-H106P) did not have a lethal effect or cross the BBB, and failed to induce a cytotoxic effect on renal epithelial cells. These data suggest a direct correlation between the lethal effect of the toxin, with its cytotoxic effect on the kidney distal tubule cells, and the ability to cross the BBB. PMID:25013927

Dorca-Arevalo, Jonatan; Pauillac, Serge; Diaz-Hidalgo, Laura; Martin-Satue, Mireia; Popoff, Michel R.; Blasi, Juan

2014-01-01

9

Toxin Plasmids of Clostridium perfringens  

PubMed Central

SUMMARY In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ?16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ?45 kb to ?140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ?35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

Li, Jihong; Adams, Vicki; Bannam, Trudi L.; Miyamoto, Kazuaki; Garcia, Jorge P.; Uzal, Francisco A.; Rood, Julian I.

2013-01-01

10

Prevention and treatment of Clostridium perfringens epsilon toxin intoxication in mice with a neutralizing monoclonal antibody (c4D7) produced in Nicotiana benthamiana.  

PubMed

Epsilon toxin (ETX), produced by Clostridium perfringens types B and D, is among the most lethal toxins known. ETX is a potential bioterrorism threat that was listed as a Category B agent by the U.S. Centers for Disease Control until 2012 and it still remains a toxin of interest for several government agencies. We produced a monoclonal antibody (MAb) against ETX (ETX MAb c4D7) in Nicotiana benthamiana and characterized its preventive and therapeutic efficacy in mice. The ETX preparation used was highly lethal for mice (LD50 = 1.6 ?g/kg) and resulted in a mean time from inoculation to death of 18 and 180 min when administered intravenously or intraperitoneally, respectively. High lethal challenge resulted in dramatic increases of a variety of pro-inflammatory cytokines in serum, while lower, but still lethal doses, did not elicit such responses. ETX MAb c4D7 was highly effective prophylactically (ED50 = 0.3 mg/kg; ED100 = 0.8 mg/kg) and also provided protection when delivered 15-30 min post-ETX intoxication. These data suggest that ETX MAb c4D7 may have use as a pre- and post-exposure treatment for ETX intoxication. PMID:24950050

Garcia, J P; Beingesser, J; Bohorov, O; Bohorova, N; Goodman, C; Kim, D; Pauly, M; Velasco, J; Whaley, K; Zeitlin, L; Roy, C J; Uzal, F A

2014-09-01

11

Quantitation of Clostridium perfringens in Foods  

PubMed Central

A procedure is described for identifying and enumerating Clostridium perfringens in foods by means of a simplified agar plating method, followed by confirmation of black colonies in tubes of motility-nitrate medium and sporulation broth. The test is routinely completed within 48 hr. Under experimental conditions, the procedure has been used to quantitatively recover various levels of C. perfringens contamination in a variety of foods and has recovered as few as ten C. perfringens per g without interference from food constituents and associated flora. Under practical conditions of field application, the method has been used to investigate five food-poisoning outbreaks, and C. perfringens was implicated as the etiological agent in two of these outbreaks. PMID:13861594

Angelotti, Robert; Hall, Herbert E.; Foter, Milton J.; Lewis, Keith H.

1962-01-01

12

Molecular genetics and pathogenesis of Clostridium perfringens.  

PubMed Central

Clostridium perfringens is the causative agent of a number of human diseases, such as gas gangrene and food poisoning, and many diseases of animals. Recently significant advances have been made in the development of C. perfringens genetics. Studies on bacteriocin plasmids and conjugative R plasmids have led to the cloning and analysis of many C. perfringens genes and the construction of shuttle plasmids. The relationship of antibiotic resistance genes to similar genes from other bacteria has been elucidated. A detailed physical map of the C. perfringens chromosome has been prepared, and numerous genes have been located on that map. Reproducible transformation methods for the introduction of plasmids into C. perfringens have been developed, and several genes coding for the production of extracellular toxins and enzymes have been cloned. Now that it is possible to freely move genetic information back and forth between C. perfringens and Escherichia coli, it will be possible to apply modern molecular methods to studies on the pathogenesis of C. perfringens infections. PMID:1779929

Rood, J I; Cole, S T

1991-01-01

13

Affinity chromatography purification of Clostridium perfringens enterotoxin.  

PubMed Central

Anti-enterotoxin immunoglobulins immobilized on CH-Sepharose or CNBr-Sepharose were used for affinity chromatography purification of Clostridium perfringens enterotoxin. Cell extracts containing enterotoxin or partially purified toxin preparations were applied to the column and nonspecifically-bound protein was eluted. NaOH was used to elute specifically bound toxin. The purity of enterotoxin purified by Sephadex G-100 chromatography followed by affinity chromatography appears similar to toxin highly purified by conventional means. The procedure can be used successfully for the rapid (less than 2 h) purification of small amounts of enterotoxin. Images PMID:170205

Scott, V N; Duncan, C L

1975-01-01

14

Alternative medium for Clostridium perfringens sporulation.  

PubMed Central

A medium containing 0.50 g of thiotone peptone, 0.30 g of soluble starch, 0.02 g of MgSO4 X 7H2O, 0.90 g of Na2HPO4 X 2H2O, 100.00 ml of distilled water, and optionally , 166 micrograms of dichloridric thiamine supported sporulation of 138 out of 141 Clostridium perfringens strains. Comparatively this medium gave a greater percentage of sporulation than five other media described previously. PMID:6331307

Tortora, J C

1984-01-01

15

Cloning and sequencing of the Clostridium perfringens enterotoxin gene  

Microsoft Academic Search

Several gene banks of Clostridium perfringens in E. coli were constructed. Using a mixture of synthetic 29-mer DNA probes clones were selected containing inserts from the C. perfringens gene coding for the enterotoxin. This has allowed sequencing of the complete gene and its flanking regions. The decuded amino acid sequence (320 a.a.) was found to differ at several sites from

MARIJKE VAN DAMME-JONGSTEN; Karel Wernars; Servé Notermans

1989-01-01

16

Tips to Prevent Illness from Clostridium Perfringens  

MedlinePLUS

... food poisoning be prevented? To prevent C. perfringens spores from growing in food after it has been ... These temperatures prevent the growth of C. perfringens spores that might have survived the initial cooking process. ...

17

Neuromuscular and Central Nervous System Manifestations of Clostridium perfringens Infections  

Microsoft Academic Search

Infections with Clostridium perfringens usually manifest locally or spread to sepsis with multiorgan involvement, hemolysis or septic shock. Central nervous system\\u000a (CNS) manifestations are rare and most frequently comprise meningitis with or without pneumencephalon, encephalitis, plexitis,\\u000a cerebral abscess, or subdural empyema. The course of CNS affections is usually foudroyant and the outcome fatal. Neuromuscular\\u000a manifestations of C. perfringens infections are

J. Finsterer; B. Hess

2007-01-01

18

Spore coat protein and enterotoxin synthesis in Clostridium perfringens.  

PubMed Central

Polyacrylamide gel profiles of Clostridium perfringens spore coat protein revealed four and occasionally five components. Pulse-chase experiments indicated that synthesis of coat protein polypeptide and enterotoxin was an early sporulation event. However, maximum synthesis occurred coincident with the onset of heat resistance. PMID:195933

Labbe, R G; Duncan, C L

1977-01-01

19

Suspected neurotoxicity due to Clostridium perfringens type B in a tiger (Panthera tigris).  

PubMed

A 4-yr-old tiger (Panthera tigris) was referred with acute onset of severe abnormal consciousness. Neurological evaluation showed normal palpebral and corneal reflexes, normal pupil diameter with normal direct and consensual papillary light reflex, and absent menace response bilaterally. Diffuse forebrain lesion or focal lesion affecting the ascending reticular activating system was suspected. Complete blood examination and cerebrospinal fluid analysis were normal. Magnetic resonance imaging of the brain showed an empty sella as the only result. Clostridium perfringens 10(4) to 10(7) colony-forming units/g were detected in fecal flora samples. Multiplex polymerase chain reaction assay identified serotype B counts with production of epsilon toxin. This toxin specifically accumulates in the central nervous system, where it causes acute neurological signs in humans, domestic animals, and wildlife. In this communication, the acute onset of neurological signs without evidence of trauma, vascular, metabolic, or inflammatory diseases may be caused by neurotoxicity due to C. perfringens. PMID:23082539

Zeira, Offer; Briola, Chiara; Konar, Martin; Dumas, Maria Pia; Wrzosek, Marcin Adam; Papa, Valentina

2012-09-01

20

Identification of Clostridium Species and DNA Fingerprinting of Clostridium perfringens by Amplified Fragment Length Polymorphism Analysis?  

PubMed Central

An amplified fragment length polymorphism (AFLP) method was applied to 129 strains representing 24 different Clostridium species, with special emphasis on pathogenic clostridia of medical or veterinary interest, to assess the potential of AFLP for identification of clostridia. In addition, the ability of the same AFLP protocol to type clostridia at the strain level was assessed by focusing on Clostridium perfringens strains. All strains were typeable by AFLP, so the method seemed to overcome the problem of extracellular DNase production. AFLP differentiated all Clostridium species tested, except for Clostridium ramosum and Clostridium limosum, which clustered together with a 45% similarity level. Other Clostridium species were divided into species-specific clusters or occupied separate positions. Wide genetic diversity was observed among Clostridium botulinum strains, which were divided into seven species-specific clusters. The same AFLP protocol was also suitable for typing C. perfringens at the strain level. A total of 29 different AFLP types were identified for 37 strains of C. perfringens; strains initially originating from the same isolate showed identical fingerprinting patterns and were distinguished from unrelated strains. AFLP proved to be a highly reproducible, easy-to-perform, and relatively fast method which enables high throughput of samples and can serve in the generation of identification libraries. These results indicate that the AFLP method provides a promising tool for the identification and characterization of Clostridium species. PMID:16971642

Keto-Timonen, Riikka; Heikinheimo, Annamari; Eerola, Erkki; Korkeala, Hannu

2006-01-01

21

Clostridium perfringens Sepsis and Fetal Demise after Genetic Amniocentesis  

PubMed Central

Clostridium perfringens is a rare cause of intrauterine infection. There have been five case reports concerning infection associated with invasive procedures. We report a woman who underwent a genetic amniocentesis due to her history of chronic granulomatous disease. She presented to the hospital ?38 hours after the amniocentesis complaining of fever and chills. Due to acute decompensation, she underwent an emergent dilatation and evacuation. During her stay, blood cultures came back positive for C. perfringens. Gradual improvement with intensive monitoring led to hospital discharge 4 days after the procedure. Uterine infection due to C. perfringens leading to maternal sepsis is associated with a high morbidity and mortality rate. Our patient was able to survive without a hysterectomy due to the rapid administration of antibiotics and surgical intervention while being evaluated. PMID:23705080

Hendrix, Nancy W.; Mackeen, A. Dhanya; Weiner, Stuart

2011-01-01

22

An observation of Clostridium perfringens in Greater Sage-Grouse.  

PubMed

Mortality due to infectious diseases is seldom reported in the Greater Sage-Grouse (Centrocercus urophasianus). A case of necrotic enteritis associated with Clostridium perfringens type A is described in a free-ranging adult male sage-grouse in eastern Oregon. Clostridial enteritis is known to cause outbreaks of mortality in various domestic and wild birds, and should be considered as a potential cause of mortality in sage-grouse populations. PMID:17699098

Hagen, Christian A; Bildfell, Robert J

2007-07-01

23

Lytic enzyme discovery through multigenomic sequence analysis in Clostridium perfringens  

PubMed Central

With their ability to lyse Gram-positive bacteria, phage lytic enzymes (or lysins) have received a great deal of attention as novel anti-infective agents. The number of known genes encoding these peptidoglycan hydrolases has increased markedly in recent years, due in large part to advances in DNA sequencing technology. As the genomes of more and more bacterial species/strains are sequenced, lysin-encoding open reading frames (ORFs) can be readily identified in lysogenized prophage regions. In the current study, we sought to assess lysin diversity for the medically relevant pathogen Clostridium perfringens. The sequenced genomes of nine C. perfringens strains were computationally mined for prophage lysins and lysin-like ORFs, revealing several dozen proteins of various enzymatic classes. Of these lysins, a muramidase from strain ATCC 13124 (termed PlyCM) was chosen for recombinant analysis based on its dissimilarity to previously characterized C. perfringens lysins. Following expression and purification, various biochemical properties of PlyCM were determined in vitro, including pH/salt-dependence and temperature stability. The enzyme exhibited activity at low µg/ml concentrations, a typical value for phage lysins. It was active against 23 of 24 strains of C. perfringens tested, with virtually no activity against other clostridial or nonclostridial species. Overall, PlyCM shows potential for development as an enzybiotic agent, demonstrating how expanding genomic databases can serve as rich pools for biotechnologically relevant proteins. PMID:21085950

Ossiprandi, Maria Cristina; Rumah, Kareem R.; Fischetti, Vincent A.

2013-01-01

24

[Dry medium for isolating Clostridium perfringens].  

PubMed

The possibility of using blood substitutes (hydrolysin, casein hydrolysate "tsolipk" and amino peptide) with expired shelf life as a culture medium for the isolation of Cl. perfringens has been studied. Dry culture medium based on these inedible products has been developed. To stimulate bacterial growth, fodder yeast extract has been used. The suppression of the growth of extraneous microflora is ensured by the use of antibiotics: polymyxin sulfate and mycerin sulfate. The recommended medium is not inferior in its quality (sensitivity, rapidity of growth, differentiating and inhibiting properties, etc.) to media based on meat and casein. The use of the newly developed medium is economically grounded and allows one to obtain standard results. PMID:6282016

Gorbushina, S N; Kaplunova, O P

1982-04-01

25

Activation and injury of Clostridium perfringens spores by alcohols.  

PubMed Central

The activation properties of Clostridium perfringens NCTC 8679 spores were demonstrated by increases in CFU after heating in water or aqueous alcohols. The temperature range for maximum activation, which was 70 to 80 degrees C in water, was lowered by the addition of alcohols. The response at a given temperature was dependent on the time of exposure and the alcohol concentration. The monohydric alcohols and some, but not all, of the polyhydric alcohols could activate spores at 37 degrees C. The concentration of a monohydric alcohol that produced optimal spore activation was inversely related to its lipophilic character. Spore injury, which was manifested as a dependence on lysozyme for germination and colony formation, occurred under some conditions of alcohol treatment that exceeded those for optimal spore activation. Treatment with aqueous solutions of monohydric alcohols effectively activated C. perfringens spores and suggests a hydrophobic site for spore activation. PMID:2864897

Craven, S E; Blankenship, L C

1985-01-01

26

[Massive intravascular hemolysis secondary to sepsis due to Clostridium perfringens].  

PubMed

Massive hemolysis secondary to sepsis caused by Clostridium perfringens is a rare entity but appears fairly often in the literature. In nearly all published reports, the clinical course is rapid and fatal. We describe the case of a 75-year-old woman with diabetes who was admitted with symptoms consistent with acute cholecystitis. Deteriorating hemodynamics and laboratory findings were consistent with intravascular hemolysis, coagulation disorder, and renal failure. Gram-positive bacilli of the Clostridium species were detected in blood along with worsening indicators of hemolysis. In spite of antibiotic and surgical treatment, hemodynamic support and infusion of blood products, the patient continued to decline and died in the postoperative recovery unit 14 hours after admission. Mortality ranges from 70% to 100% in sepsis due to Clostridium perfringens, and risk of death is greater if massive hemolysis is present, as in the case we report. Only a high degree of clinical suspicion leading to early diagnosis and treatment can improve the prognosis. This bacterium should therefore be considered whenever severe sepsis and hemolysis coincide. PMID:20527348

Pita Zapata, E; Sarmiento Penide, A; Bautista Guillén, A; González Cabano, M; Agulla Budiño, J A; Camba Rodríguez, M A

2010-05-01

27

Catecholamine and cyclic nucleotide response of sheep to the injection of Clostridium welchii type D epsilon toxin.  

PubMed

Injection of Clostridium welchii (C. perfringens) type D epsilon toxin into sheep caused large increases in catecholamine and cyclic adenosine 3',5'-monophosphate levels and moderate increases in cyclic guanosine 3',5'-monophosphate levels. Haemoconcentration also occurred. It is suggested that a rapidly developing brain oedema is the stimulus for a release of catecholamines which in turn activates adenyl cyclase. The resulting rise in cAMP causes glycogenolysis and hyperglycaemia. PMID:229224

Worthington, R W; Bertschinger, H J; Mülders, M S

1979-11-01

28

Genetic Characterization of Type A Enterotoxigenic Clostridium perfringens Strains  

PubMed Central

Clostridium perfringens type A, is both a ubiquitous environmental bacterium and a major cause of human gastrointestinal disease, which usually involves strains producing C. perfringens enterotoxin (CPE). The gene (cpe) encoding this toxin can be carried on the chromosome or a large plasmid. Interestingly, strains carrying cpe on the chromosome and strains carrying cpe on a plasmid often exhibit different biological characteristics, such as resistance properties against heat. In this study, we investigated the genetic properties of C. perfringens by PCR-surveying 21 housekeeping genes and genes on representative plasmids and then confirmed those results by Southern blot assay (SB) of five genes. Furthermore, sequencing analysis of eight housekeeping genes and multilocus sequence typing (MLST) analysis were also performed. Fifty-eight C. perfringens strains were examined, including isolates from: food poisoning cases, human gastrointestinal disease cases, foods in Japan or the USA, or feces of healthy humans. In the PCR survey, eight of eleven housekeeping genes amplified positive reactions in all strains tested. However, by PCR survey and SB assay, one representative virulence gene, pfoA, was not detected in any strains carrying cpe on the chromosome. Genes involved in conjugative transfer of the cpe plasmid were also absent from almost all chromosomal cpe strains. MLST showed that, regardless of their geographic origin, date of isolation, or isolation source, chromosomal cpe isolates, i) assemble into one definitive cluster ii) lack pfoA and iii) lack a plasmid related to the cpe plasmid. Similarly, independent of their origin, strains carrying a cpe plasmid also appear to be related, but are more variable than chromosomal cpe strains, possibly because of the instability of cpe-borne plasmid(s) and/or the conjugative transfer of cpe-plasmid(s) into unrelated C. perfringens strains. PMID:19479065

Kuwahara, Tomomi; Miki, Yasuhiro; Kaneko, Ikuko; Li, Jihong; McClane, Bruce A.; Akimoto, Shigeru

2009-01-01

29

Isolation of Clostridium perfringens Type B in an Individual at First Clinical Presentation of Multiple Sclerosis Provides Clues for Environmental Triggers of the Disease  

PubMed Central

We have isolated Clostridium perfringens type B, an epsilon toxin-secreting bacillus, from a young woman at clinical presentation of Multiple Sclerosis (MS) with actively enhancing lesions on brain MRI. This finding represents the first time that C. perfringens type B has been detected in a human. Epsilon toxin’s tropism for the blood-brain barrier (BBB) and binding to oligodendrocytes/myelin makes it a provocative candidate for nascent lesion formation in MS. We examined a well-characterized population of MS patients and healthy controls for carriage of C. perfringens toxinotypes in the gastrointestinal tract. The human commensal Clostridium perfringens type A was present in approximately 50% of healthy human controls compared to only 23% in MS patients. We examined sera and CSF obtained from two tissue banks and found that immunoreactivity to ETX is 10 times more prevalent in people with MS than in healthy controls, indicating prior exposure to ETX in the MS population. C. perfringens epsilon toxin fits mechanistically with nascent MS lesion formation since these lesions are characterized by BBB permeability and oligodendrocyte cell death in the absence of an adaptive immune infiltrate. PMID:24146858

Rumah, Kareem Rashid; Linden, Jennifer; Fischetti, Vincent A.; Vartanian, Timothy

2013-01-01

30

Enterotoxin formation by Clostridium perfringens type A in a defined medium.  

PubMed Central

Enterotoxin was produced by 9 of 10 strains of Clostridium perfringens type A when grown in a defined medium. Additional dextrin increased the amount of enterotoxin in extracts of sporulating cells of strain NCTC 10239. PMID:6261685

Labbe, R G

1981-01-01

31

Sensitization by Ethylenediaminetetraacetate of Clostridium perfringens Type A Spores to Germination by Lysozyme1  

PubMed Central

Clostridium perfringens spores (three strains) were normally resistant to germination by lysozyme. In the absence of disulfide bond-breaking reagents, tetrasodium ethylenediaminetetraacetate rapidly sensitized the spores to lysozyme. PMID:4355485

Adams, D. M.

1973-01-01

32

Nonradioactive colony hybridization assay for detection and enumeration of enterotoxigenic Clostridium perfringens in raw beef.  

PubMed Central

A DNA probe endolabeled with digoxigenin by PCR was developed to detect and enumerate enterotoxigenic Clostridium perfringens in raw beef. After 2 h of hybridization, membranes were developed by using an anti-digoxigenin-alkaline phosphatase conjugated antibody. The resulting chromogenic reaction allowed us to detect and enumerate < or = 10 CFU of C. perfringens per g. PMID:7574619

Baez, L A; Juneja, V K

1995-01-01

33

Dietary Glycine Concentration Affects Intestinal Clostridium perfringens and Lactobacilli Populations in Broiler Chickens1  

Microsoft Academic Search

Previous studies have reported that intesti- nal populations of Clostridium perfringens, the causative agent of necrotic enteritis (NE), are correlated with diets high in glycine. To establish a direct causative link, 3 trials were conducted to examine the effect of dietary glycine levels on gut populations of C. perfringens, ?-toxin production, and NE lesion scores in broiler chickens. In trials

J. P. Dahiya; D. Hoehler; D. C. Wilkie; A. G. Van Kessel; M. D. Drew

34

Molecular Subtyping of Poultry-Associated Type A Clostridium perfringens Isolates by Repetitive-Element PCR  

Microsoft Academic Search

Clostridium perfringens strains (type A) isolated from an integrated poultry operation were subtyped using repetitive-element PCR with Dt primers. Isolates were obtained from fecal, egg shell, fluff, and carcass rinse samples as part of a previously reported temporally linked epidemiological survey. A total of 48 isolates of C. perfringens were obtained from different stages of the broiler chicken production chain

G. R. Siragusa; M. D. Danyluk; K. L. Hiett; M. G. Wise; S. E. Craven

2006-01-01

35

Clostridium perfringens in Long Island Sound sediments: An urban sedimentary record  

USGS Publications Warehouse

Clostridium perfringens is a conservative tracer and an indicator of sewage-derived pollution in the marine environment. The distribution of Clostridium perfringens spores was measured in sediments from Long Island Sound, USA, as part of a regional study designed to: (1) map the distribution of contaminated sediments; (2) determine transport and dispersal paths; (3) identify the locations of sediment and contaminant focusing; and (4) constrain predictive models. In 1996, sediment cores were collected at 58 stations, and surface sediments were collected at 219 locations throughout the Sound. Elevated concentrations of Clostridium perfringens in the sediments indicate that sewage pollution is present throughout Long Island Sound and has persisted for more than a century. Concentrations range from undetectable amounts to 15,000 spores/g dry sediment and are above background levels in the upper 30 cm at nearly all core locations. Sediment focusing strongly impacts the accumulation of Clostridium perfringens spores. Inventories in the cores range from 28 to 70,000 spores/cm2, and elevated concentrations can extend to depths of 50 cm. The steep gradients in Clostridium perfringens profiles in muddier cores contrast with concentrations that are generally constant with depth in sandier cores. Clostridium perfringens concentrations rarely decrease in the uppermost sediment, unlike those reported for metal contaminants. Concentrations in surface sediments are highest in the western end of the Sound, very low in the eastern region, and intermediate in the central part. This pattern reflects winnowing and focusing of Clostridium perfringens spores and fine-grained sediment by the hydrodynamic regime; however, the proximity of sewage sources to the westernmost Sound locally enhances the Clostridium perfringens signals.

Buchholtz ten Brink, M. R.; Mecray, E.L.; Galvin, E.L.

2000-01-01

36

Massive Intravascular Hemolysis From Clostridium perfringens Septicemia: A Review.  

PubMed

We describe the case of a patient with hemolysis-associated Clostridium perfringens septicemia and review all similar cases published in the literature since 1990, with specific focus on the relationship between treatment strategy and survival. We searched PubMed for all published cases of C. perfringens-associated hemolysis, using the medical subject terms "clostridia," "clostridial sepsis," and/or "hemolysis." All case reports, case series, review articles, and other relevant references published in the English literature since 1990 were included in this study. There were no exclusion criteria. Each case was examined with respect to presenting features of illness, antibiotic regimen, time-to-antibiotic therapy, additional interventions, complications, and patient survival. These variables were entered into a data set and then systematically analyzed with the aid of a statistician, using serial t tests and chi-square analyses. Since 1990, 50 patients of C. perfringens septicemia with hemolysis have been reported. Median age was 61 years (range 31-84), and 58% were male. Mortality was 74%, with a median time to death of 9.7 hours (range 0-96 hours). Of the patients, 35 (70%) were treated medically, while 15 (30%) received antibiotics and surgery. Surgical intervention was associated with significantly improved survival (risk ratio [RR] 0.23, 95% confidence interval [CI] 0.10, 0.53) as was the use of a combination of penicillin and clindamycin (RR of death 0.46, 95% CI 0.25, 0.83). Four patients utilizing hyperbaric oxygen therapy (HBOT) have been reported, and all patients survived. In cases of clostridial sepsis with hemolysis, strong predictors of survival include early initiation of appropriate antibiotics as well as surgical removal of infected foci. The HBOT may also be associated with survival. The disease often progresses rapidly to death, so rapid recognition is critical for the patient survival. PMID:24019300

Simon, Tracey G; Bradley, Joanna; Jones, Adisa; Carino, Gerardo

2014-11-01

37

Characterization of toxin plasmids in Clostridium perfringens type C isolates.  

PubMed

Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasmid borne among a collection of type C isolates. Those analyses revealed that the surveyed type C isolates carry their beta toxin-encoding gene (cpb) on plasmids ranging in size from ?65 to ?110 kb. When present in these type C isolates, the beta2 toxin gene localized to plasmids distinct from the cpb plasmid. However, some enterotoxin-positive type C isolates appeared to carry their enterotoxin-encoding cpe gene on a cpb plasmid. The tpeL gene encoding the large clostridial cytotoxin was localized to the cpb plasmids of some cpe-negative type C isolates. The cpb plasmids in most surveyed isolates were found to carry both IS1151 sequences and the tcp genes, which can mediate conjugative C. perfringens plasmid transfer. A dcm gene, which is often present near C. perfringens plasmid-borne toxin genes, was identified upstream of the cpb gene in many type C isolates. Overlapping PCR analyses suggested that the toxin-encoding plasmids of the surveyed type C isolates differ from the cpe plasmids of type A isolates. These findings provide new insight into plasmids of proven or potential importance for type C virulence. PMID:20823204

Gurjar, Abhijit; Li, Jihong; McClane, Bruce A

2010-11-01

38

Enterotoxin synthesis by nonsporulating cultures of Clostridium perfringens.  

PubMed Central

Chemostat-cultured Clostridium perfringens ATCC 3624 and NCTC 10240, and a nonsporulating mutant strain, 8-5, produced enterotoxin in the absence of sporulation when cultured in a chemically defined medium at a 0.084-h-1 dilution rate at 37 degrees C. The enterotoxin was detected by serological and biological assays. Examination of the chemostat cultures by electron microscopy did not reveal sporulation at any stage. The culture maintained enterotoxigenicity throughout cultivation in a continuous system. The enterotoxin was detected in batch cultures of each strain cultivated in fluid thioglycolate medium and a chemically defined medium. No heat-resistant or light-refractile spores were detected in batch cultures during the exponential growth. Images PMID:2876679

Goldner, S B; Solberg, M; Jones, S; Post, L S

1986-01-01

39

Cytology of Spore Formation in Clostridium perfringens1  

PubMed Central

The sequential morphological events in spore formation by Clostridium perfringens type D were observed in Ellner's medium where 80 to 100% of the cells formed spores. Gross structural changes were studied with the light microscope under phase-contrast, and in fixed cells by the use of both nigrosin and Giemsa preparations. Fine structure was examined with the electron microscope in both thin sections and frozen-etched preparations. During the first 3 hr of incubation, the original rod-shaped cells became ellipsoid to ovoid in shape; by 5 to 6 hr, subterminal spores had developed within these enlarged cells. The fine structural sequence was in most respects identical to that in other Bacillaceae, although some stages were illustrated with particular clarity. A unique feature was the development of a convoluted, membranous exosporium which adhered to the outer surface of the two coats and had an unusual fine structure resembling a rectangular array of subunits. Images PMID:4302300

Hoeniger, Judith F. M.; Stuart, Philip F.; Holt, Stanley C.

1968-01-01

40

Evaluation of CP Chromo Select Agar for the enumeration of Clostridium perfringens from water.  

PubMed

The European Directive on drinking water quality has included mCP agar as the reference method for recovering Clostridium perfringens from drinking waters. In the present study, three media (mCP, TSCF and CP Chromo Select Agar) were evaluated for recovery of C. perfringens in different surface water samples. Out of 139 water samples, using a membrane filtration technique, 131 samples (94.2%) were found to be presumptively positive for C. perfringens in at least one of the culture media. Green colored colonies on CP Chromo Select Agar (CCP agar) were counted as presumptive C. perfringens isolates. Out of 483 green colonies on CCP agar, 96.3% (465 strains, indole negative) were identified as C. perfringens, and 15 strains (3.1%) were indole positive and were identified as Clostridium sordellii, Clostridium bifermentans or Clostridium tetani. Only 3 strains (0.6%) gave false positive results and were identified as Clostridium fallax, Clostridium botulinum, and Clostridium tertium. Variance analysis of the data obtained shows statistically no significant differences in the counts obtained between media employed in this work. The mCP method is very onerous for routine screening and bacterial colonies could not be used for further biochemical testing. The colonies on CCP and TSCF were easy to count and subculture for confirmation tests. TSCF detects sulfite-reducing clostridia, including species other than C. perfringens, and in some cases excessive blackening of the agar frustrated counting of the colonies. If the contamination was too high, TSCF did not consistently produce black colonies and as a consequence, the colonies were white and gave false negative results. On the other hand, the identification of typical and atypical colonies isolated from all media demonstrated that CCP agar was the most useful medium for C. perfringens recovery in water samples. PMID:23816139

Manafi, Mammad; Waldherr, Kerstin; Kundi, Michael

2013-10-01

41

Clostridium perfringens type A enterotoxin damages the rabbit colon.  

PubMed

Clostridium perfringens enterotoxin causes the gastrointestinal (GI) symptoms of C. perfringens type A food poisoning and CPE-associated non-food-borne human GI diseases. It is well established that CPE induces fluid accumulation and severe tissue damage in ligated small intestinal loops of rabbits and other animals. However, a previous study had also reported that CPE binds to rabbit colonic cells yet does not significantly affect rabbit colonic loops. To the contrary, the current study determined that treatment with 50 or 100 ?g/ml of CPE causes significant histologic lesions and luminal fluid accumulation in rabbit colonic loops. Interestingly, a CPE-neutralizing monoclonal antibody blocked the development of CPE-induced histologic damage but not luminal fluid accumulation in these loops. Similar luminal fluid accumulation, without significant histologic damage, also occurred after treatment of colonic loops with heat-inactivated CPE, antibody alone, or bovine serum albumin (BSA), indicating that increased osmolarity was causing or contributing to fluid accumulation in CPE-treated colonic loops. Comparative studies revealed the similar development of histologic damage and luminal fluid accumulation in both small intestinal loops and colonic loops after as little as a 1-h treatment with 50 ?g/ml of CPE. Consistent with the CPE sensitivity of the small intestine and colon, Western blotting detected CPE binding and large-complex formation in both organs. In addition, Western blotting demonstrated the presence of the high-affinity CPE receptors claudin-3 and -4 in both organs of rabbits, consistent with the observed toxin binding. Collectively, these results offer support for the possible involvement of the colon in CPE-mediated GI disease. PMID:24643537

Garcia, Jorge P; Li, Jihong; Shrestha, Archana; Freedman, John C; Beingesser, Juliann; McClane, Bruce A; Uzal, Francisco A

2014-06-01

42

Clostridium perfringens Type A Enterotoxin Damages the Rabbit Colon  

PubMed Central

Clostridium perfringens enterotoxin causes the gastrointestinal (GI) symptoms of C. perfringens type A food poisoning and CPE-associated non-food-borne human GI diseases. It is well established that CPE induces fluid accumulation and severe tissue damage in ligated small intestinal loops of rabbits and other animals. However, a previous study had also reported that CPE binds to rabbit colonic cells yet does not significantly affect rabbit colonic loops. To the contrary, the current study determined that treatment with 50 or 100 ?g/ml of CPE causes significant histologic lesions and luminal fluid accumulation in rabbit colonic loops. Interestingly, a CPE-neutralizing monoclonal antibody blocked the development of CPE-induced histologic damage but not luminal fluid accumulation in these loops. Similar luminal fluid accumulation, without significant histologic damage, also occurred after treatment of colonic loops with heat-inactivated CPE, antibody alone, or bovine serum albumin (BSA), indicating that increased osmolarity was causing or contributing to fluid accumulation in CPE-treated colonic loops. Comparative studies revealed the similar development of histologic damage and luminal fluid accumulation in both small intestinal loops and colonic loops after as little as a 1-h treatment with 50 ?g/ml of CPE. Consistent with the CPE sensitivity of the small intestine and colon, Western blotting detected CPE binding and large-complex formation in both organs. In addition, Western blotting demonstrated the presence of the high-affinity CPE receptors claudin-3 and -4 in both organs of rabbits, consistent with the observed toxin binding. Collectively, these results offer support for the possible involvement of the colon in CPE-mediated GI disease. PMID:24643537

Garcia, Jorge P.; Li, Jihong; Shrestha, Archana; Freedman, John C.; Beingesser, Juliann; McClane, Bruce A.

2014-01-01

43

Comparative Analysis of Prevalence, Risk Factors, and Molecular Epidemiology of Antibiotic-Associated Diarrhea Due to Clostridium difficile, Clostridium perfringens, and Staphylococcus aureus  

Microsoft Academic Search

We prospectively studied the comparative epidemiology and risk factors for Clostridium difficile, Clostridium perfringens, and Staphylococcus aureus antibiotic-associated diarrhea (AAD). Four thousand six hundred fifty- nine inpatient fecal specimens (11 months) were tested for C. difficile cytotoxin, C. perfringens enterotoxin, and S. aureus by Vero cell assay, enzyme-linked immunosorbent assay, and growth on fresh blood agar, respectively. Two distinct age-,

N. J. Asha; D. Tompkins; M. H. Wilcox

2006-01-01

44

Spore lytic enzyme released from Clostridium perfringens spores during germination.  

PubMed Central

The exudate of fully germinated spores of Clostridium perfringens was found to contain a large amount of a spore lytic enzyme which acted directly on alkali-treated spores of the organism to cause germination. Although no detectable amount of the enzyme was found in dormant spores during germination in a KCl medium, the enzyme was produced rapidly and released into the medium. The optimal conditions for enzyme activity were pH 6.0 and 45 degrees C. Maximum activity occurred in the presence of various univalent cations at a concentration of 50 mM. The enzyme was readily inactivated by several sulfhydryl reagents. A strong reducing condition was generated in the ionic germination of the spores, a minimum Eh level of -350 mV being reached 30 min after initiation of germination. Furthermore, adenosine triphosphate-dependent pyruvate:ferredoxin oxidoreductase (EC 1.2.7.1) was identified in both dorman and germinated spores. The relationship between the release of active enzyme and the generation of reducing conditions during germination is discussed. PMID:227836

Ando, Y

1979-01-01

45

Clostridium perfringens Enterotoxin Interacts with Claudins via Electrostatic Attraction*  

PubMed Central

Clostridium perfringens enterotoxin (CPE), a causative agent of food poisoning, is a pore-forming toxin disrupting the selective permeability of the plasma membrane of target cells, resulting in cell death. We previously identified claudin as the cell surface receptor for CPE. Claudin, a component of tight junctions, is a tetratransmembrane protein and constitutes a large family of more than 20 members, not all of which serve as the receptor for CPE. The mechanism by which the toxin distinguishes the sensitive claudins is unknown. In this study, we localized the region of claudin responsible for interaction with CPE to the C-terminal part of the second extracellular loop and found that the isoelectric point of this region in sensitive claudins was higher than insensitive claudins. Amino acid substitutions to lower the pI resulted in reduced sensitivity to CPE among sensitive claudins, whereas substitutions to raise the pI endowed CPE-insensitive claudins with sensitivity. The steric structure of the claudin-binding domain of CPE reveals an acidic cleft surrounded by Tyr306, Tyr310, Tyr312, and Leu315, which were reported to be essential for interaction with the sensitive claudins. These results imply that an electrostatic attraction between the basic claudin region and the acidic CPE cleft is involved in their interaction. PMID:19903817

Kimura, Jun; Abe, Hiroyuki; Kamitani, Shigeki; Toshima, Hirono; Fukui, Aya; Miyake, Masami; Kamata, Yoichi; Sugita-Konishi, Yoshiko; Yamamoto, Shigeki; Horiguchi, Yasuhiko

2010-01-01

46

Investigating the role of small, acid-soluble spore proteins (SASPs) in the resistance of Clostridium perfringens spores to heat  

Microsoft Academic Search

BACKGROUND: Clostridium perfringens type A food poisoning is caused by enterotoxigenic C. perfringens type A isolates that typically possess high spore heat-resistance. The molecular basis for C. perfringens spore heat-resistance remains unknown. In the current study, we investigated the role of small, acid-soluble spore proteins (SASPs) in heat-resistance of spores produced by C. perfringens food poisoning isolates. RESULTS: Our current

Deepa Raju; Michael Waters; Peter Setlow; Mahfuzur R Sarker

2006-01-01

47

Kinetics of spore coat protein synthesis by Clostridium perfringens type A  

Microsoft Academic Search

Spore coat proteins of several strains ofClostridium perfringens were analyzed by immunoblotting with antisera against two major spore coat proteins, one [34-kilodalton (kDa)] from an enterotoxin-positive and one (19-kDa) from an enterotoxin-negative (ent-) strain of this organism. The results indicated that spore coat proteins from many strains ofC. perfringens were immunologically related regardless of their ability to produce enterotoxin, but

Sangryeol Ryu I; Ronald G. Labbé

1992-01-01

48

Rapid Confirmation of Clostridium perfringens by Using Chromogenic and Fluorogenic Substrates  

PubMed Central

The use of 4-methylumbelliferyl phosphate (MUP) and ortho-nitrophenyl-?-d-galactopyranoside (ONPG) for the identification of Clostridium perfringens was investigated. A liquid assay containing both MUP and ONPG was a highly specific alternative method for C. perfringens confirmation, reducing incubation time from 48 to only 4 h. The assay solution is easy to prepare, does not require anaerobic conditions for use, and has an extended shelf life. PMID:11526053

Adcock, Philip W.; Saint, Christopher P.

2001-01-01

49

A middle-aged lady with a pyogenic liver abscess caused by Clostridium perfringens  

PubMed Central

The pyogenic liver abscess caused by Clostridium perfringens (C. perfringens) is a rare, but rapidly fatal infection. It is usually associated with malignancy and immunosuppression. We report the case of 50-year-old lady with the secondary liver metastases from rectal cancer presented with fever and epigastric pain. The identification of Gram-positive bacilli septicaemia, the presence of gas-forming liver abscess and massive intravascular hemolysis should lead to the suspicion of C. perfringens infection. Here we review twenty cases published since 1990 and their clinical features are discussed. The importance of ”an aggressive treatment policy” with multidisciplinary team approach is emphasized. PMID:22993668

Law, Siu-Tong; Lee, Ming Kai

2012-01-01

50

Enterotoxin formation by different toxigenic types of Clostridium perfringens.  

PubMed Central

Sixty-nine strains of Clostridium perfringens of different toxigenic types were investigated for enterotoxin production. Enterotoxin was definitively detected only in strains of types A and C. This is the first report where enterotoxin production has been demonstrated in a toxigenic type other than type A. The exterotoxin-positive type C strains were isolated from cases of enteritis necroticans ("pig bel+) in New Guinea. The major enterotoxin from type C showed a reaction of complete identity with enterotoxin from type A in immunodiffusion using anti-enterotoxin serum prepared against the latter; it induced erythema when injected intradermally into depilated guinea pigs and caused fluid accumulation in the rabbit ileal loop. The results indicate that the major enterotoxin from type C was serologically and biologically similar to enterotoxin from type A. In some C was serologically and biologically similar to enterotoxin from type A. In some type C strains, an enterotoxin was detected that showed a reaction of partial serological identity. Spore coat proteins were extracted from 14-strains by alkaline dithiothreitol, and the extracts were assayed for enterotoxin-like spore protein. Enterotoxin could be extracted from type A and type C spores, and all positive strains showed a reaction of complete identity in immunodiffusion with enterotoxin obtained from cell extracts of type A. Disc immunoelectrophoresis demonstrated that two distinct components that reacted serologically with anti-enterotoxin serum were present in both the cell extract and in extracted spore protein from one type C strain. These distinct components differed in molecular weight. Images PMID:163799

Skjelkvale, R; Duncan, C L

1975-01-01

51

Effect of cysteine modifications on the activity of the ‘small’ Clostridium perfringens sialidase  

Microsoft Academic Search

The ‘small’ (43 kDa) sialidase of Clostridium perfringens is inhibited by low concentrations of mercury ions. For the investigation of possible functional roles of the enzyme's four cysteine residues at the amino acid positions 2, 282, 333 and 349, they were separately altered to serine by site-directed mutagenesis. The four mutant sialidases expressed in E. coli and purified by metal

Susanne Kruses; Jorg Pommerencke; Reinhard G Kleineidam; Peter Roggentin; Roland Schauer

1998-01-01

52

Alphitobius diaperinus como veiculador de Clostridium perfringens em granjas avícolas do interior paulista - Brasil  

Microsoft Academic Search

The Alphitobius diaperinus (lesser mealworm) is considered an important world poultry plague. Due to its behavior characteristics and biological habits that make its control difficult it is considered a vector of pathogenic agents. The objective of this research was to investigate the little mealworm as possible vector of Clostridium perfringens in broiler houses, located in different parts of the state

Juliano VittoriI Rubén; Pablo Schocken-IturrinoI; César Augusto Martins; Gislaine Gomes; Caroline Peters

53

Effect of Clostridium perfringens alpha toxin on the isolated rat vas deferens.  

PubMed

Alpha toxin produced by Clostridium perfringens potentiated norepinephrine-evoked contraction in the isolated rat vas deferens, but itself caused no contraction within 60 min. The potentiating activity was dependent on the dose of the toxin and was quantitatively related to the phospholipase C activity of the toxin preparation. PMID:2862722

Sakurai, J; Nomura, S; Fujii, Y; Oshita, Y

1985-01-01

54

Responses of broiler chickens orally challenged with Clostridium perfringens isolated from field cases of necrotic enteritis  

Microsoft Academic Search

The present study examines the responses of broiler chickens to oral administration of Clostridium perfringens freshly isolated from field cases of necrotic enteritis (NE). The challenge studies included long-term exposure and short-term exposure, factored in with dietary and management variables including high levels of dietary components such as fish meal, meat meal, abrupt change of feed, and fasting. In the

A. A. Olkowski; C. Wojnarowicz; M. Chirino-Trejo; M. D. Drew

2006-01-01

55

Determination of toxinotypes of environmental Clostridium perfringens by Polymerase Chain Reaction.  

PubMed

Toxinotype of Clostridium perfringens (CP) isolates collected from the Bernam River, Selangor River and Tengi Canal between April 2007 and January 2008 were determined by Polymerase Chain Reaction (PCR) using published primers. All the 147 isolates were toxinotype Type A, harbouring the alpha toxin gene. In addition, 5 of the isolates also had the enterotoxin (CPE) gene. PMID:21602783

Florence L, C H; Hakim, S L; Kamaluddin, M A; Thong, K L

2011-04-01

56

BEC, a Novel Enterotoxin of Clostridium perfringens Found in Human Clinical Isolates from Acute Gastroenteritis Outbreaks  

PubMed Central

Clostridium perfringens is a causative agent of food-borne gastroenteritis for which C. perfringens enterotoxin (CPE) has been considered an essential factor. Recently, we experienced two outbreaks of food-borne gastroenteritis in which non-CPE producers of C. perfringens were strongly suspected to be the cause. Here, we report a novel enterotoxin produced by C. perfringens isolates, BEC (binary enterotoxin of C. perfringens). Culture supernatants of the C. perfringens strains showed fluid-accumulating activity in rabbit ileal loop and suckling mouse assays. Purification of the enterotoxic substance in the supernatants and high-throughput sequencing of genomic DNA of the strains revealed BEC, composed of BECa and BECb. BECa and BECb displayed limited amino acid sequence similarity to other binary toxin family members, such as the C. perfringens iota toxin. The becAB genes were located on 54.5-kb pCP13-like plasmids. Recombinant BECb (rBECb) alone had fluid-accumulating activity in the suckling mouse assay. Although rBECa alone did not show enterotoxic activity, rBECa enhanced the enterotoxicity of rBECb when simultaneously administered in suckling mice. The entertoxicity of the mutant in which the becB gene was disrupted was dramatically decreased compared to that of the parental strain. rBECa showed an ADP-ribosylating activity on purified actin. Although we have not directly evaluated whether BECb delivers BECa into cells, rounding of Vero cells occurred only when cells were treated with both rBECa and rBECb. These results suggest that BEC is a novel enterotoxin of C. perfringens distinct from CPE, and that BEC-producing C. perfringens strains can be causative agents of acute gastroenteritis in humans. Additionally, the presence of becAB on nearly identical plasmids in distinct lineages of C. perfringens isolates suggests the involvement of horizontal gene transfer in the acquisition of the toxin genes. PMID:24664508

Yonogi, Shinya; Matsuda, Shigeaki; Kawai, Takao; Yoda, Tomoko; Harada, Tetsuya; Kumeda, Yuko; Gotoh, Kazuyoshi; Hiyoshi, Hirotaka; Nakamura, Shota; Kodama, Toshio

2014-01-01

57

BEC, a novel enterotoxin of Clostridium perfringens found in human clinical isolates from acute gastroenteritis outbreaks.  

PubMed

Clostridium perfringens is a causative agent of food-borne gastroenteritis for which C. perfringens enterotoxin (CPE) has been considered an essential factor. Recently, we experienced two outbreaks of food-borne gastroenteritis in which non-CPE producers of C. perfringens were strongly suspected to be the cause. Here, we report a novel enterotoxin produced by C. perfringens isolates, BEC (binary enterotoxin of C. perfringens). Culture supernatants of the C. perfringens strains showed fluid-accumulating activity in rabbit ileal loop and suckling mouse assays. Purification of the enterotoxic substance in the supernatants and high-throughput sequencing of genomic DNA of the strains revealed BEC, composed of BECa and BECb. BECa and BECb displayed limited amino acid sequence similarity to other binary toxin family members, such as the C. perfringens iota toxin. The becAB genes were located on 54.5-kb pCP13-like plasmids. Recombinant BECb (rBECb) alone had fluid-accumulating activity in the suckling mouse assay. Although rBECa alone did not show enterotoxic activity, rBECa enhanced the enterotoxicity of rBECb when simultaneously administered in suckling mice. The entertoxicity of the mutant in which the becB gene was disrupted was dramatically decreased compared to that of the parental strain. rBECa showed an ADP-ribosylating activity on purified actin. Although we have not directly evaluated whether BECb delivers BECa into cells, rounding of Vero cells occurred only when cells were treated with both rBECa and rBECb. These results suggest that BEC is a novel enterotoxin of C. perfringens distinct from CPE, and that BEC-producing C. perfringens strains can be causative agents of acute gastroenteritis in humans. Additionally, the presence of becAB on nearly identical plasmids in distinct lineages of C. perfringens isolates suggests the involvement of horizontal gene transfer in the acquisition of the toxin genes. PMID:24664508

Yonogi, Shinya; Matsuda, Shigeaki; Kawai, Takao; Yoda, Tomoko; Harada, Tetsuya; Kumeda, Yuko; Gotoh, Kazuyoshi; Hiyoshi, Hirotaka; Nakamura, Shota; Kodama, Toshio; Iida, Tetsuya

2014-06-01

58

Synthetic DNA probes for detection of enterotoxigenic Clostridium perfringens strains isolated from outbreaks of food poisoning.  

PubMed Central

Four synthetic oligonucleotides encoding different parts of the Clostridium perfringens enterotoxin gene were used to test the enterotoxigenicity of C. perfringens strains isolated from confirmed outbreaks of food poisoning. Of the 245 strains isolated from food and feces originating from 186 separate outbreaks, 145 (59%) gave hybridization reactions with each of the four DNA probes used, while 104 strains did not hybridize with any of the probes. There was no correlation between serotype and the presence of the enterotoxin gene, although the C. perfringens enterotoxin gene was rarely detected among nontypable strains (17%). Results show that DNA hybridization is a suitable method for the identification of C. perfringens strains which have the potential to produce enterotoxin. PMID:2298871

Van Damme-Jongsten, M; Rodhouse, J; Gilbert, R J; Notermans, S

1990-01-01

59

Clostridium perfringens and Clostridium difficile in cooked beef sold in Côte d'Ivoire and their antimicrobial susceptibility.  

PubMed

The aim of this study was to evaluate the prevalence of Clostridium difficile and Clostridium perfringens in cooked beef sold in the streets in Côte d'Ivoire and their antimicrobial susceptibility. A total of 395 kidney and flesh samples of cooked beef were collected from vendors at Abidjan and subjected to C. difficile and C. perfringens isolation and identification by using biochemical tests, API 20A system and PCR detection. Subsequently, the antimicrobial susceptibility test was performed for confirmed isolates. Our results showed the prevalence of 12.4% for C. difficile (11.04% in kidney and 13.45% in flesh) and 5.06% for C. perfringens (2.32% in kidney and 7.17% in flesh). Metronidazole and vancomycin remained the most potent antimicrobial agents against C. difficile while metronidazole and penicillin G were the most potent agents against C. perfringens. The resistance rates to tetracycline, doxycycline, chloramphenicol and erythromycin against C. difficile and C. perfringens isolates ranged from 2.05% to 8.16% and from 20% to 50%, respectively. Among all antimicrobial agents tested against C. difficile, percentages of resistance to quinolones ciprofloxacin, norfloxacin and nalidixic acid as well as to gentamicin and cefotaxime were the highest. Eight resistant phenotypes were defined for C. difficile isolates and eleven resistant phenotypes for C. perfringens isolates. Clindamycin/gentamicin/cefotaxime/ciprofloxacin/norfloxacin/nalidixic acid resistance was the most common phenotype for C. difficile (55.10% of isolates) while norfloxacin/nalidixic acid resistance was the most common phenotype for C. perfringens (20% of isolates). PMID:24944124

Kouassi, Kra Athanase; Dadie, Adjéhi Thomas; N'Guessan, Kouadio Florent; Dje, Koffi Marcellin; Loukou, Yao Guillaume

2014-08-01

60

Freshwater Suspended Sediments and Sewage Are Reservoirs for Enterotoxin-Positive Clostridium perfringens?  

PubMed Central

The release of fecal pollution into surface waters may create environmental reservoirs of feces-derived microorganisms, including pathogens. Clostridium perfringens is a commonly used fecal indicator that represents a human pathogen. The pathogenicity of this bacterium is associated with its expression of multiple toxins; however, the prevalence of C. perfringens with various toxin genes in aquatic environments is not well characterized. In this study, C. perfringens spores were used to measure the distribution of fecal pollution associated with suspended sediments in the nearshore waters of Lake Michigan. Particle-associated C. perfringens levels were greatest adjacent to the Milwaukee harbor and diminished in the nearshore waters. Species-specific PCR and toxin gene profiles identified 174 isolates collected from the suspended sediments, surface water, and sewage influent as C. perfringens type A. Regardless of the isolation source, the beta2 and enterotoxin genes were common among isolates. The suspended sediments yielded the highest frequency of cpe-carrying C. perfringens (61%) compared to sewage (38%). Gene arrangement of enterotoxin was investigated using PCR to target known insertion sequences associated with this gene. Amplification products were detected in only 9 of 90 strains, which suggests there is greater variability in cpe gene arrangement than previously described. This work presents evidence that freshwater suspended sediments and sewage influent are reservoirs for potentially pathogenic cpe-carrying C. perfringens spores. PMID:20581181

Mueller-Spitz, Sabrina R.; Stewart, Lisa B.; Klump, J. Val; McLellan, Sandra L.

2010-01-01

61

Microbiological and Physico-Chemical Evaluation of Mortadellas Elaborated with Essential Oils and Inoculated with Clostridium perfringens Type A.  

E-print Network

??Clostridium perfringens is a rod-shaped, gram-positive, anaerobic, non-motile, spore-forming and oxygen tolerant bacterium and it is directly associated to food-poisoning. Since the growth of customers… (more)

Nayane Aparecida Araujo Dias

2011-01-01

62

Importance of histamine-producing Clostridium perfringens in scombrotoxin-forming fish.  

PubMed

It has been suggested that anaerobic histamine-producing bacteria (HPB) are important contributors to scombrotoxin fish poisoning (SFP). In order to assess the role of Clostridium perfringens in SFP, we developed a real-time PCR method for rapid detection of histamine-producing (HP) C. perfringens. The real-time PCR assay was 100% inclusive for detecting 23 HP C. perfringens and did not detect any of the other 116 HP or non-HP isolates examined. The efficiency of the assay with or without internal amplification control DNA was 102%; in the presence of background flora and inhibitory matrices, it was 90 to 99%. To investigate the importance of HP C. perfringens in SFP, we examined histamine production by C. perfringens in inoculated fish samples incubated under anaerobic conditions. C. perfringens produced low histamine levels in tuna (19 ppm) and Spanish mackerel (3 ppm), whereas gram-negative HPB produced high histamine levels (6,345 ppm in tuna; 1,223 ppm in Spanish mackerel) under the same conditions. When one bonito, two bigeye tuna, nine mahi-mahi, and five yellowfin tuna were examined for the presence of HPB, none (0 of 17) of the samples contained HP C. perfringens or other gram-positive HPB, whereas 86% of the samples contained gram-negative HPB. Our study indicates that histamine production by C. perfringens in scombrotoxin-forming fish was minimal compared with that by gram-negative HPB and that C. perfringens may not be an important bacterial species associated with SFP. PMID:23834808

Bjornsdottir-Butler, Kristin; McCarthy, Susan; Burkhardt, William; Benner, Ronald A

2013-07-01

63

Skewed genomic variability in strains of the toxigenic bacterial pathogen, Clostridium perfringens  

PubMed Central

Clostridium perfringens is a Gram-positive, anaerobic spore-forming bacterium commonly found in soil, sediments, and the human gastrointestinal tract. C. perfringens is responsible for a wide spectrum of disease, including food poisoning, gas gangrene (clostridial myonecrosis), enteritis necroticans, and non-foodborne gastrointestinal infections. The complete genome sequences of Clostridium perfringens strain ATCC 13124, a gas gangrene isolate and the species type strain, and the enterotoxin-producing food poisoning strain SM101, were determined and compared with the published C. perfringens strain 13 genome. Comparison of the three genomes revealed considerable genomic diversity with >300 unique “genomic islands” identified, with the majority of these islands unusually clustered on one replichore. PCR-based analysis indicated that the large genomic islands are widely variable across a large collection of C. perfringens strains. These islands encode genes that correlate to differences in virulence and phenotypic characteristics of these strains. Significant differences between the strains include numerous novel mobile elements and genes encoding metabolic capabilities, strain-specific extracellular polysaccharide capsule, sporulation factors, toxins, and other secreted enzymes, providing substantial insight into this medically important bacterial pathogen. PMID:16825665

Myers, Garry S.A.; Rasko, David A.; Cheung, Jackie K.; Ravel, Jacques; Seshadri, Rekha; DeBoy, Robert T.; Ren, Qinghu; Varga, John; Awad, Milena M.; Brinkac, Lauren M.; Daugherty, Sean C.; Haft, Daniel H.; Dodson, Robert J.; Madupu, Ramana; Nelson, William C.; Rosovitz, M.J.; Sullivan, Steven A.; Khouri, Hoda; Dimitrov, George I.; Watkins, Kisha L.; Mulligan, Stephanie; Benton, Jonathan; Radune, Diana; Fisher, Derek J.; Atkins, Helen S.; Hiscox, Tom; Jost, B. Helen; Billington, Stephen J.; Songer, J. Glenn; McClane, Bruce A.; Titball, Richard W.; Rood, Julian I.; Melville, Stephen B.; Paulsen, Ian T.

2006-01-01

64

Growth of Clostridium perfringens in Food Proteins Previously Exposed to Proteolytic Bacilli1  

PubMed Central

Proteolytic sporeforming bacteria capable of surviving processing heat treatments in synthetic or fabricated protein foods exhibited no antagonistic effects on growth of Clostridium perfringens, but instead shortened the lag of subsequent growth of C. perfringens in sodium caseinate and isolated soy protein. Bacillus subtilis A cells were cultured in 3% sodium caseinate or isolated soy protein solutions. The subsequent effect on the lag time and growth of C. perfringens type A (strain S40) at 45 C was measured by colony count or absorbance at 650 nm, or both. B. subtilis incubation for 12 h or more in sodium caseinate reduced the C. perfringens lag by 3 h. Incubation of 8 h or more in isolated soy protein reduced the lag time by 1.5 h. Molecular sieving of the B. subtilis-treated sodium caseinate revealed that all molecular sizes yielded a similar reduced lag time. Diethylaminoethyl-Sephadex ion exchange fractionation and subsequent amino acid analysis indicated that the lag time reduction caused by B. subtilis incubation was not related to charge of the peptides nor to their amino acid composition. Apparently the shortened C. perfringens lag in these B. subtilis-hydrolyzed food proteins was a result of the protein being more readily available for utilization by C. perfringens. PMID:4357650

Schroder, D. J.; Busta, F. F.

1973-01-01

65

Toxinotyping of Clostridium perfringens Fecal Isolates of Reintroduced Père David's Deer (Elaphurus davidianus) in China.  

PubMed

Abstract Clostridium perfringens is an important pathogen causing sudden death syndrome, necrotic enteritis, and gas gangrene in ruminants, especially some deer species. Père David's deer (Elaphurus davidianus) is one of the world's rare species and is an endangered and protected species in China. Some Père David's deer in the Chinese Shishou Père David's Deer Preserve died due to C. perfringens infection. We investigated the toxin types and C. perfringens enterotoxin-positive (cpe(+)) strains of isolated C. perfringens in Père David's deer in China. We collected 155 fecal samples from the Beijing Nanhaizi Père David's Deer Park and the Jiangsu Dafeng Père David's Deer National Nature Reserve between July 2010 and July 2011. Bacteria isolated using blood agar and mannitol agar plates were identified by Gram staining and nested PCR for 16S rRNA. We isolated C. perfringens from 41 fecal samples and used PCR amplification of five toxin genes to identify the toxinotypes and the cpe(+) strains of C. perfringens. Twenty-one isolates were type A, 15 were type E, and five were type D. Fifteen isolates were cpe(+) strains, including eight that were type A and seven that were type E. PMID:25050802

Qiu, Huiling; Chen, Fu; Leng, Xinyan; Fei, Rongmei; Wang, Libo

2014-10-01

66

Characterization of a parasporal inclusion body from sporulating, enterotoxin-positive Clostridium perfringens type A.  

PubMed Central

Inclusion bodies (IB) synthesized during sporulation and enterotoxin formation by Clostridium perfringens NCTC 8239 and 8798 were isolated and characterized. IB were isolated by disruption of sporangia by sonication in the presence of tetrasodium EDTA and phenylmethylsulfonyl fluoride. Fractionation was carried out in a linear gradient of sodium bromide, sucrose, or diatrizoate sodium. Denaturing and reducing agents were necessary to solubilize the IB. An alkylating agent was required to prevent reaggregation of the subunits. Molecular weight, compositional, and serological analyses and peptide mapping revealed strong similarities between the IB subunits and the enterotoxin synthesized during sporulation by C. perfringens. IB appear to represent the structural component where overproduced enterotoxin accumulates intracellularly. Enterotoxin-like subunits in the IB appeared to be held together by noncovalent and disulfide bonds, which were generally resistant to the action of intracellular proteases of C. perfringens, trypsin, or trypsin plus bile salts. Images PMID:2867991

Loffler, A; Labbe, R

1986-01-01

67

Rapid detection of Clostridium perfringens type A enterotoxin by enzyme-linked immunosorbent assay.  

PubMed Central

Clostridium perfringens type A enterotoxin was specifically detected and readily quantified by indirect and four-layer sandwich enzyme-linked immunosorbent assays (ELISAs). With the indirect ELISA, enterotoxin was detected in quantities of as low as 2.5 ng (25 ng/ml). When the more sensitive sandwich ELISA procedures was used, 100 pg (1 ng/ml) of enterotoxin was detected. The sandwich ELISA procedure specifically detected enterotoxin in human fecal extracts. Additionally, the sandwich ELISA specifically differentiated enterotoxin-positive strains from enterotoxin-negative strains of C. perfringens. Both the indirect and sandwich ELISA procedures described for C. perfringens enterotoxin in this report are rapid, specific, sensitive, and easily adaptable for large-scale use by clinical or research laboratories. PMID:6321542

McClane, B A; Strouse, R J

1984-01-01

68

Unique Regulatory Mechanism of Sporulation and Enterotoxin Production in Clostridium perfringens  

PubMed Central

Clostridium perfringens causes gas gangrene and gastrointestinal (GI) diseases in humans. The most common cause of C. perfringens-associated food poisoning is the consumption of C. perfringens vegetative cells followed by sporulation and production of enterotoxin in the gut. Despite the importance of spore formation in C. perfringens pathogenesis, the details of the regulation of sporulation have not yet been defined fully. In this study, microarray and bioinformatic analyses identified a candidate gene (the RNA regulator virX) for the repression of genes encoding positive regulators (Spo0A and sigma factors) of C. perfringens sporulation. A virX mutant constructed in the food poisoning strain SM101 had a much higher sporulation efficiency than that of the wild type. The transcription of sigE, sigF, and sigK was strongly induced at 2.5 h of culture of the virX mutant. Moreover, the transcription of the enterotoxin gene was also strongly induced in the virX mutant. Western blotting confirmed that the levels of enterotoxin production were higher in the virX mutant than in the wild type. These observations indicated that the higher levels of sporulation and enterotoxin production in the virX mutant were specifically due to inactivation of the virX gene. Since virX homologues were not found in any Bacillus species but were present in other clostridial species, our findings identify further differences in the regulation of sporulation between Bacillus and certain Clostridium species. The virX RNA regulator plays a key role in the drastic shift in lifestyle of the anaerobic flesh eater C. perfringens between the vegetative state (for gas gangrene) and the sporulating state (for food poisoning). PMID:23585540

Ohtani, Kaori; Hirakawa, Hideki; Paredes-Sabja, Daniel; Tashiro, Kosuke; Kuhara, Satoru; Sarker, Mahfuzur R.

2013-01-01

69

Cloning, sequencing and expression of the acylneuraminate lyase gene from Clostridium perfringens A99  

Microsoft Academic Search

The acylneuraminate lyase gene from Clostridium perfringens A99 was cloned on a 3.3 kb HindIII DNA fragment identified by screening the chromosomal DNA of this species by hybridization with an oligonucleotide probe\\u000a that had been deduced from the N-terminal amino acid sequence of the purified protein, and another probe directed against\\u000a a region that is conserved in the acylneuraminate lyase

Christina Traving; Peter Roggentin; Roland Schauert

1997-01-01

70

Sporulation and enterotoxin production by Clostridium perfringens type A at 37 and 43 degrees C.  

PubMed Central

Enterotoxin-positive strains of Clostridium perfringens were grown in Duncan-Strong sporulation medium in the presence of 0.4% (7.9 mM) raffinose at 37 and 43 degrees C. Enterotoxin- and heat-resistant spores were produced at similar concentrations but sooner at 43 degrees C than at 37 degrees C. There was a direct relationship between spore heat resistance and sporulation temperature (32, 37, and 43 degrees C). Images PMID:1599261

Garcia-Alvarado, J S; Labbe, R G; Rodriguez, M A

1992-01-01

71

Large outbreaks of Clostridium perfringens food poisoning associated with the consumption of boiled salmon.  

PubMed Central

Five large outbreaks of food poisoning are described in which clinical, epidemiological or laboratory data indicated Clostridium perfringens as the causative organism. The foodstuff common to all incidents was boiled salmon served cold as an hors d 'oeuvre. In all cases the fish had been subject to a long period of cooling or storage between boiling and consumption. It is thought that multiplication of the organism occurred during this time. Recommendations are made for the avoidance of further similar incidents. PMID:2874173

Hewitt, J. H.; Begg, N.; Hewish, J.; Rawaf, S.; Stringer, M.; Theodore-Gandi, B.

1986-01-01

72

[Cloning of Clostridium perfringens alpha-toxin gene and extracellular expression in Escherichia coli].  

PubMed

Clostridium perfringens (C. perfringens) is a Gram-positive bacterial pathogen that widely propagets in the soil and the gastrointestinal tract of human and animals. This bacteria causes food poisoning, gas gangrene and other various range of infectious diseases. But there is no standard diagnosis method of C. perfringens. In order to develop a new type of immunoassay for clinical purpose, we studied expression and extracellular secretion of recombinant alpha-toxin having enzyme activity in E. coli expression system. Cloning was carried out after PCR amplification from C. perfringens GAI 94074 which was clinical isolate. Three kinds of fragment were cloned using pET100/D-TOPO vector. These fragments coded for ribosome binding site, signal peptide, and alpha-toxin gene respectively. Recombinant pET100 plasmid transformed into TOP 10 cells and the obtained plasmids were transformed into BL21 (DE3) cells. Then, the transformants were induced expression with IPTG. In conclusion, we successfully cloned, expressed and exteracellular secreted C. perfringens alpha-toxin containing signal peptide. Biologically, the obtained recombinant protein was positive for phospholipase C activity. PMID:18154441

Inoue, Masaharu; Kikuchi, Maho; Komoriya, Tomoe; Watanabe, Kunitomo; Kouno, Hideki

2007-01-01

73

New medium for rapid screening and enumeration of Clostridium perfringens in foods.  

PubMed Central

A rapid and sensitive procedure for estimating low numbers of Clostridium perfringens has been investigated and compared to methods used currently in the food industry. The new liquid medium, RPM (rapid perfringens medium), was compared with sulfite-polymyxin-sulfadiazine agar and tryptose-sulfite-cycloserine agar in recovery studies with naturally contaminated and with inoculated foods. The medium consists of a mixture of litmus milk and fluid thioglycolate medium fortified with glucose, peptone, gelatin, yeast extract, sodium chloride, and ferrous sulfate. Selectivity is based on an antibiotic system (polymyxin B sulfate and neomycin sulfate) incorporated into the medium, coupled with an incubation temprature of 46 to 48 degrees C for 24 h. Tubes were scored as positive if a stormy fermentation was observed. All tubes demonstrating stormy fermentation were confirmed as containing C. perfringens. Of a total of 774 naturally contaminated food samples, 546 samples (71%) were found to contain C. perfringens with RPM, whereas only 168 (22%) of the samples were positive using sulfite-polymyxin-sulfadiazine agar. C. perfringens was isolated from 71% of 85 other samples using RPM as compared to 14% with tryptose-sulfite-cycloserine agar. Enumeration studies on 14 individual samples using the most probable number technique also demonstrated greater sensitivity with RPM. PMID:213019

Erickson, J E; Deibel, R H

1978-01-01

74

Benthic Distribution of Sewage Sludge Indicated by Clostridium perfringens at a Deep-Ocean Dump Site †  

PubMed Central

Clostridium perfringens in sediment samples collected at the Deep Water Municipal Sewage Sludge Disposal Site (also called the 106-Mile Site), off the coast of New Jersey, was enumerated. The counts of C. perfringens found in sediment samples collected within and to the southwest of the 106-Mile Site were significantly elevated (P < 0.01) compared with counts of samples from reference stations of similar depth (2,400 to 2,700 m), topography, and distance from the continental shelf, indicating that the benthic environment was contaminated by sewage dumping at this site. Low counts of C. perfringens in sediment samples collected at stations between the base of the continental shelf and the 106-Mile Site indicated that coastal runoff was not a significant source of contamination. Elevated counts were observed for samples up to 92 km to the southwest, whereas low counts were obtained for samples from stations to the east of the 106-Mile Site. This distribution is consistent with previous model predictions of sludge deposition. In areas heavily impacted by sludge dumping, C. perfringens counts were generally highest in the top 1 cm of sediment and exceeded 9,000 CFU g (dry weight) of sediment-1. The patterns of C. perfringens dispersal observed in this study have proved useful for selection of heavily impacted areas and control stations for further ecological evaluation by a multidisciplinary research team. PMID:16348859

Hill, Russell T.; Knight, Ivor T.; Anikis, Michael S.; Colwell, Rita R.

1993-01-01

75

Benthic distribution of sewage sludge indicated by clostridium perfringens at a deep-ocean dump site  

SciTech Connect

Clostridium perfringens in sediment samples collected at the Deep Water Municipal Sewage Sludge Disposal Site (also called the 106-Mile Site), off the coast of New Jersey, was enumerated. The counts of C. perfringens found in sediment samples collected within and to the southwest of the 106-Mile Site were significantly elevated (P. < 0.01) compared with counts of samples from reference stations of similar depth (2,400 to 2,700 m), topography, and distance from the continental shelf, indicating that the benthic environment was contaminated by sewage dumping at the site. Low counts of C. perfringens in sediment samples collected at stations between the base of the continental shelf and the 106-Mile Site indicated that coastal runoff was not a significant source of contamination. Elevated counts were observed for samples up to 92 km to the southwest, whereas low counts were obtained for samples from stations to the east of the 106-Mile Site. The distribution is consistent with previous model predictions of sludge deposition. In areas heavily impacted by sludge dumping, C. perfringens counts were generally highest in the top 1 cm of sediment and exceeded 9,000 CFU g (dry weight) of sediment. The patterns of C. perfringens dispersal observed in the study have proved useful for selection of heavily impacted areas and control stations for further ecological evaluation by a multidisciplinary research team.

Hill, R.T.; Knight, I.T.; Anikis, M.S.; Colwell, R.R.

1993-01-01

76

Production of an antibacterial substance in the digestive tract involved in colonization-resistance against Clostridium perfringens  

Microsoft Academic Search

Ruminococcus gnavus E1, Bacteroides thetaiotaomicron LEMF4, Clostridium hathewayi LEMC7, and Clostridium orbiscindens LEMH9 were isolated from ex germ-free mice inoculated with a human faecal microbiota. When initially germ-free mice who were previously inoculated with the strain E1 alone, or a four-strain consortium [E1, LEMF4, LEMC7, and LEMH9], were then challenged with 108 counts of Clostridium perfringens; the target strain was

E. H. Crost; A. Pujol; M. Ladiré; J. Dabard; P. Raibaud; J. P. Carlier; M. Fons

2010-01-01

77

Biofilm formation of Clostridium perfringens and its exposure to low-dose antimicrobials.  

PubMed

Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Very little is known on the biofilm of C. perfringens and its exposure to subminimal inhibitory concentrations of antimicrobials. This study was undertaken to address these issues. Most of the C. perfringens human and animal isolates tested in this study were able to form biofilm (230/277). Porcine clinical isolates formed significantly more biofilm than the porcine commensal isolates. A subgroup of clinical and commensal C. perfringens isolates was randomly selected for further characterization. Biofilm was found to protect C. perfringens bacterial cells from exposure to high concentrations of tested antimicrobials. Exposure to low doses of some of these antimicrobials tended to lead to a diminution of the biofilm formed. However, a few isolates showed an increase in biofilm formation when exposed to low doses of tylosin, bacitracin, virginiamycin, and monensin. Six isolates were randomly selected for biofilm analysis using scanning laser confocal microscopy. Of those, four produced more biofilm in presence of low doses of bacitracin whereas biofilms formed without bacitracin were thinner and less elevated. An increase in the area occupied by bacteria in the biofilm following exposure to low doses of bacitracin was also observed in the majority of isolates. Morphology examination revealed flat biofilms with the exception of one isolate that demonstrated a mushroom-like biofilm. Matrix composition analysis showed the presence of proteins, beta-1,4 linked polysaccharides and extracellular DNA, but no poly-beta-1,6-N-acetyl-D-glucosamine. This study brings new information on the biofilm produced by C. perfringens and its exposure to low doses of antimicrobials. PMID:24795711

Charlebois, Audrey; Jacques, Mario; Archambault, Marie

2014-01-01

78

Biofilm formation of Clostridium perfringens and its exposure to low-dose antimicrobials  

PubMed Central

Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Very little is known on the biofilm of C. perfringens and its exposure to subminimal inhibitory concentrations of antimicrobials. This study was undertaken to address these issues. Most of the C. perfringens human and animal isolates tested in this study were able to form biofilm (230/277). Porcine clinical isolates formed significantly more biofilm than the porcine commensal isolates. A subgroup of clinical and commensal C. perfringens isolates was randomly selected for further characterization. Biofilm was found to protect C. perfringens bacterial cells from exposure to high concentrations of tested antimicrobials. Exposure to low doses of some of these antimicrobials tended to lead to a diminution of the biofilm formed. However, a few isolates showed an increase in biofilm formation when exposed to low doses of tylosin, bacitracin, virginiamycin, and monensin. Six isolates were randomly selected for biofilm analysis using scanning laser confocal microscopy. Of those, four produced more biofilm in presence of low doses of bacitracin whereas biofilms formed without bacitracin were thinner and less elevated. An increase in the area occupied by bacteria in the biofilm following exposure to low doses of bacitracin was also observed in the majority of isolates. Morphology examination revealed flat biofilms with the exception of one isolate that demonstrated a mushroom-like biofilm. Matrix composition analysis showed the presence of proteins, beta-1,4 linked polysaccharides and extracellular DNA, but no poly-beta-1,6-N-acetyl-D-glucosamine. This study brings new information on the biofilm produced by C. perfringens and its exposure to low doses of antimicrobials. PMID:24795711

Charlebois, Audrey; Jacques, Mario; Archambault, Marie

2014-01-01

79

A recombinant carboxy-terminal domain of alpha-toxin protects mice against Clostridium perfringens.  

PubMed

Clostridium perfringens alpha-toxin (CP, 370 residues) is one of the main agents involved in the development of gas gangrene. In this study, the immunogenicity and protective efficacy of the C-terminal domain (CP251-370) of the toxin and phospholipase C (PLC; CB, 372 residues) of Clostridum bifermentans isolated from cases of clostridium necrosis were examined. The recombinant proteins were expressed as glutathione S-transferase (GST) fusion proteins. Antibodies that cross-reacted with alpha-toxin were produced after immunization with recombinant proteins including GST-CP251-370, GST-CP281-370, GST-CP311-370, CB1-372 and GST-CB251-372. Anti-GST-CP251-370, anti-GST-CP281-370 and anti-GST-CP311-370 sera neutralized both the PLC and hemolytic activities of alpha-toxin, whereas anti-CB1-372 and anti-GST-CB251-372 weakly neutralized these activities. Immunization with GST-CP251-370 and GST-CP281-370 provided protection against the lethal effects of the toxin and C. perfringens type A NCTC8237. Partial protection from the toxin and C. perfringens was elicited by immunization with GST-CP311-370 and CB1-372. GST-CP251-370 and GST-CP281-370 are promising candidates for vaccines for clostridial-induced gas gangrene. PMID:23668605

Nagahama, Masahiro; Oda, Masataka; Kobayashi, Keiko; Ochi, Sadayuki; Takagishi, Teruhisa; Shibutani, Masahiro; Sakurai, Jun

2013-05-01

80

Identification of glutamate ABC-Transporter component in Clostridium perfringens as a putative drug target.  

PubMed

Clostridium perfringens is an anaerobic pathogen known to cause vast number of diseases in mammals and birds. Various toxins and hydrolysing enzymes released by the organism are responsible for the necrosis of soft tissues. Due to serious safety issues associated with current vaccines against C. perfringens, there is a need for new drug or vaccine targets. C. perfringens is extremely dependent on its host for nutrition which can be targeted for vaccine development or drug design. Therefore, it is of interest to identify the unique transport systems used by C. perfringens involved in uptake of essential amino acids that are synthesized by the host, so that therapeutic agents can be designed to target the specific transport systems. Use of bioinformatics tools resulted in the identification of a protein component of the glutamate transport system that is not present in the host. Analysis of the conservation profile of the protein domain indicated it to be a glutamate binding protein which also stimulates the ATPase activity of ATP Binding Cassettes (ABC) transporters. Homology modelling of the protein showed two distinct lobes, which is a characteristic of substrate binding proteins. This suggests that the carboxylates of glutamate might be stabilized by electrostatic interactions with basic residues as is observed with other binding proteins. Hence, the homology model of this potential drug target can be employed for in silico docking studies by suitable inhibitors. PMID:25187678

Bhatia, Bharti; Ponia, Sanket Singh; Solanki, Amit Kumar; Dixit, Aparna; Garg, Lalit C

2014-01-01

81

Characterization of two putative fibronectin-binding proteins of Clostridium perfringens.  

PubMed

Clostridium perfringens is a Gram-positive anaerobic pathogen that causes gas gangrene and food poisoning in humans and animals. Genomic analysis of C. perfringens strain 13 revealed that this bacterium contains two genes (CPE0737 and CPE1847) that encode putative fibronectin (Fn)-binding proteins (Fbps). These genes, named fbpA and fbpB, were found to be constitutively expressed in all three strains (13, NCTC8237, CPN50) of C. perfringens, isolated from gas gangrene of human, that were tested. Both fbpA and fbpB were cloned and His-tagged, recombinant FbpA (rFbpA) and recombinant FbpB (rFbpB) were purified by Ni(2+)-Sepharose column chromatography from transformed Escherichia coli. These recombinant Fbps were shown to bind to Fn, purified from human serum, in a ligand blotting assay. Additionally, Fn bound to these rFbps in a dose-dependent manner in an enzyme-linked immunosorbent assay. Furthermore, it was found that pre-incubation of Fn with either rFbpA or rFbpB inhibited the binding of Fn to C. perfringens cells. PMID:19292998

Katayama, Seiichi; Nozu, Nanami; Okuda, Masaya; Hirota, Shinsuke; Yamasaki, Tsutomu; Hitsumoto, Yasuo

2009-08-01

82

UDP-glucose deficiency causes hypersensitivity to the cytotoxic effect of Clostridium perfringens phospholipase C.  

PubMed

A Chinese hamster cell line with a mutation in the UDP-glucose pyrophosphorylase (UDPG:PP) gene leading to UDP-glucose deficiency as well as a revertant cell were previously isolated. We now show that the mutant cell is 10(5) times more sensitive to the cytotoxic effect of Clostridium perfringens phospholipase C (PLC) than the revertant cell. To clarify whether there is a connection between the UDP-glucose deficiency and the hypersensitivity to C. perfringens PLC, stable transfectant cells were prepared using a wild type UDPG:PP cDNA. Clones of the mutant transfected with a construct having the insert in the sense orientation had increased their UDP-glucose level, whereas those of the revertant transfected with a UDPG:PP antisense had reduced their level of UDP-glucose compared with control clones transfected with the vector. Exposure of these two types of transfectant clones to C. perfringens PLC demonstrated that a cellular UDP-glucose deficiency causes hypersensitivity to the cytotoxic effect of this phospholipase. Further experiments with genetically engineered C. perfringens PLC variants showed that the sphingomyelinase activity and the C-domain are required for its cytotoxic effect in UDP-glucose-deficient cells. PMID:9733734

Flores-Díaz, M; Alape-Girón, A; Titball, R W; Moos, M; Guillouard, I; Cole, S; Howells, A M; von Eichel-Streiber, C; Florin, I; Thelestam, M

1998-09-18

83

Comparison of Western immunoblots and gene detection assays for identification of potentially enterotoxigenic isolates of Clostridium perfringens.  

PubMed Central

Clostridium perfringens enterotoxin (CPE) is an important sporulation-associated virulence factor in several illnesses of humans and domestic animals, including C. perfringens type A food poisoning. Therefore, the ability to determine the enterotoxigenicity of food or fecal C. perfringens isolates with simple, rapid assays should be helpful for epidemiologic investigations. In this study, Western immunoblotting (to detect CPE production in vitro) was compared with PCR assays and digoxigenin-labeled probe assays (to detect all or part of the cpe gene) as a method for determining the enterotoxigenicity of C. perfringens isolates. The cpe detection assays yielded reliable results with DNA purified from vegetative C. perfringens cultures, while Western immunoblots required in vitro sporulation of C. perfringens isolates to detect CPE production. Several cpe-positive C. perfringens isolates from diarrheic animals did not sporulate in vitro under commonly used sporulation-inducing conditions and consequently tested CPE negative. This result indicates that cpe gene detection and serologic CPE assays do not necessarily yield similar conclusions about the enterotoxigenicity of a C. perfringens isolate. Until further studies resolve whether these cpe-positive isolates which do not sporulate in vitro can or cannot sporulate and produce CPE in vivo, it may be preferable to use cpe detection assays for evaluating C. perfringens isolate enterotoxigenicity and thereby avoid potential false-negative conclusions which may occur with serologic assays. Images PMID:7814493

Kokai-Kun, J F; Songer, J G; Czeczulin, J R; Chen, F; McClane, B A

1994-01-01

84

Enterotoxigenic Clostridium perfringens type A isolated from intestinal contents of cattle, sheep and chickens.  

PubMed Central

One hundred and fourteen strains of Clostridium perfringens, isolated from the intestinal contents of cattle, sheep, and chickens with enteritis or other disease conditions were studied for their ability to produce enterotoxin. Reversed passive hemagglutination, fluorescent antibody and immunodiffusion tests were used. On the basis of the reversed passive hemagglutination titres, supported by the other two tests, enterotoxigenicity of the strains was arbitrarily classified into two categories: highly enterotoxigenic and potentially enterotoxigenic, with 12% falling into each category. All the highly enterotoxigenic strains originated from cases of enteritis and included all three animal species. Apart from enterotoxigenicity, one C. perfringens strain produced beta toxin (type C) and 21 strains produced large amounts of alpha-toxin. The latter strains were predominantly associated with necrotic enteritis in chickens. PMID:210914

Niilo, L

1978-01-01

85

SEROLOGY OF THE SOLUBLE ANTIGENS OF CLOSTRIDIUM PERFRINGENS TYPES A-F BY AGAR-GEL DIFFUSION  

PubMed Central

Ellner, Paul D. (University of Vermont, Burlington) and Carolyn D. Bohan. Serology of the soluble antigens of Clostridium perfringens types A–F by agar-gel diffusion. J. Bacteriol. 83:284–296. 1962.—A serological study by agar-gel diffusion of the soluble antigens of 39 strains of the Clostridium perfringens group has shown them to be extremely heterogeneous. Strain variation occurred within the six types, and common antigens shared among the six types were frequently observed. Attempts to produce type-specific sera by absorption were unsuccessful, due to incomplete removal of common antibodies. Images PMID:13890020

Ellner, Paul D.; Bohan, Carolyn D.

1962-01-01

86

Sequence of Two Plasmids from Clostridium perfringens Chicken Necrotic Enteritis Isolates and Comparison with C. perfringens Conjugative Plasmids  

PubMed Central

Twenty-six isolates of Clostridium perfringens of different MLST types from chickens with necrotic enteritis (NE) (15 netB-positive) or from healthy chickens (6 netB-positive, 5 netB-negative) were found to contain 1–4 large plasmids, with most netB-positive isolates containing 3 large and variably sized plasmids which were more numerous and larger than plasmids in netB-negative isolates. NetB and cpb2 were found on different plasmids consistent with previous studies. The pathogenicity locus NELoc1, which includes netB, was largely conserved in these plasmids whereas NeLoc3, present in the cpb2 containing plasmids, was less well conserved. A netB-positive and a cpb2-positive plasmid were likely to be conjugative, and the plasmids were completely sequenced. Both plasmids possessed the intact tcp conjugative region characteristic of C. perfringens conjugative plasmids. Comparative genomic analysis of nine CpCPs, including the two plasmids described here, showed extensive gene rearrangements including pathogenicity locus and accessory gene insertions around rather than within the backbone region. The pattern that emerges from this analysis is that the major toxin-containing regions of the variety of virulence-associated CpCPs are organized as complex pathogenicity loci. How these different but related CpCPs can co-exist in the same host has been an unanswered question. Analysis of the replication-partition region of these plasmids suggests that this region controls plasmid incompatibility, and that CpCPs can be grouped into at least four incompatibility groups. PMID:23189158

Parreira, Valeria R.; Costa, Marcio; Eikmeyer, Felix; Blom, Jochen; Prescott, John F.

2012-01-01

87

Sequence of two plasmids from Clostridium perfringens chicken necrotic enteritis isolates and comparison with C. perfringens conjugative plasmids.  

PubMed

Twenty-six isolates of Clostridium perfringens of different MLST types from chickens with necrotic enteritis (NE) (15 netB-positive) or from healthy chickens (6 netB-positive, 5 netB-negative) were found to contain 1-4 large plasmids, with most netB-positive isolates containing 3 large and variably sized plasmids which were more numerous and larger than plasmids in netB-negative isolates. NetB and cpb2 were found on different plasmids consistent with previous studies. The pathogenicity locus NELoc1, which includes netB, was largely conserved in these plasmids whereas NeLoc3, present in the cpb2 containing plasmids, was less well conserved. A netB-positive and a cpb2-positive plasmid were likely to be conjugative, and the plasmids were completely sequenced. Both plasmids possessed the intact tcp conjugative region characteristic of C. perfringens conjugative plasmids. Comparative genomic analysis of nine CpCPs, including the two plasmids described here, showed extensive gene rearrangements including pathogenicity locus and accessory gene insertions around rather than within the backbone region. The pattern that emerges from this analysis is that the major toxin-containing regions of the variety of virulence-associated CpCPs are organized as complex pathogenicity loci. How these different but related CpCPs can co-exist in the same host has been an unanswered question. Analysis of the replication-partition region of these plasmids suggests that this region controls plasmid incompatibility, and that CpCPs can be grouped into at least four incompatibility groups. PMID:23189158

Parreira, Valeria R; Costa, Marcio; Eikmeyer, Felix; Blom, Jochen; Prescott, John F

2012-01-01

88

Cloning, sequencing and expression of the acylneuraminate lyase gene from Clostridium perfringens A99.  

PubMed

The acylneuraminate lyase gene from Clostridium perfringens A99 was cloned on a 3.3 kb HindIII DNA fragment identified by screening the chromosomal DNA of this species by hybridization with an oligonucleotide probe that had been deduced from the N-terminal amino acid sequence of the purified protein, and another probe directed against a region that is conserved in the acylneuraminate lyase gene of Escherichia coli and in the putative gene of Clostridium tertium. After cloning, three of the recombinant clones expressed lyase activity above the background of the endogenous enzyme of the E. coli host. The sequenced part of the cloned fragment contains the complete acylneuraminate lyase gene (ORF2) of 864 bp that encodes 288 amino acids with a calculated molecular weight of 32.3 kDa. The lyase structural gene follows a noncoding region with an inverted repeat and a ribosome binding site. Upstream from this regulatory region another open reading frame (ORF1) was detected. The 3'-terminus of the lyase structural gene is followed by a further ORF (ORF3). A high homology was found between the amino acid sequences of the sialate lyases from Clostridium perfringens and Haemophilus influenzae (75% identical amino acids) or Trichomonas vaginalis (69% identical amino acids), respectively, whereas the similarity to the gene from E. coli is low (38% identical amino acids). Based on our new sequence data, the 'large' sialidase gene and the lyase gene of C. perfringens are not arranged next to each other on the chromosome of this species. PMID:9511987

Traving, C; Roggentin, P; Schauer, R

1997-11-01

89

Ulcerative enteritis-like disease associated with Clostridium perfringens type A in bobwhite quail (Colinus virginianus).  

PubMed

Ulcerative enteritis-like disease due to Clostridium perfringens type A was attributed as the cause of mortality in excess of 50% in a flock of 1000, 10-to-16-wk-old bobwhite quail (Colinus virginianus). Clinical signs in these birds ranged from sudden death to listlessness, depression, watery white droppings, ruffled feathers, loss of weight, and death in a few days. Necropsy of 30 birds revealed multiple deep ulcers of the mucosa throughout the small intestine and ceca, some with perforation and subsequent coelomitis (peritonitis). The livers in some birds contained white foci of necrosis, and many birds had enlarged and congested spleens. Microscopic lesions included multifocal severe fibrinosuppurative ulcerative enteritis associated with large numbers of rod-shaped gram-positive bacteria, and necrotizing hepatitis with or without rod-shaped bacteria. Anaerobic culturing of the intestine and liver yielded pure cultures of C. perfringens. The C perfringens isolates were of genotype A and were polymerase chain reaction-positive for alpha toxin and for cpb2, the structural gene for beta2 toxin. Repeated attempts to isolate C colinum by using a specialized medium containing 8% horse plasma were not fruitful, suggesting that the enteritis and hepatitis in these birds were produced by C pefringens. Retrospective examination of records of quail submissions to the California Animal Health and Food Safety Laboratory System over 16 yr revealed at least nine quail submissions in which isolation of C. perfringens from the liver, intestine, or both was associated with ulcerative enteritis and hepatitis in quail. This is the first description of ulcerative enteritis-like disease in quail associated with C perfringens. Final conclusions await experimental reproduction of the disease. PMID:19166055

Shivaprasad, H L; Uzal, Francisco; Kokka, Randy; Fisher, Derek J; McClane, Bruce A; Songer, A Glenn

2008-12-01

90

Comparative Proteomic Analysis of Extracellular Proteins of Clostridium perfringens Type A and Type C Strains? †  

PubMed Central

Clostridium perfringens is a medically important clostridial pathogen and an etiological agent causing several diseases in humans and animals. C. perfringens and its toxins have been listed as potential biological and toxin warfare (BTW) agents; thus, efforts to develop strategies for detection and protection are warranted. Forty-eight extracellular proteins of C. perfringens type A and type C strains have been identified here using a 2-dimensional gel electrophoresis-mass spectrometry (2-DE-MS) technique. The SagA protein, the DnaK-type molecular chaperone hsp70, endo-beta-N-acetylglucosaminidase, and hypothetical protein CPF_0656 were among the most abundant proteins secreted by C. perfringens ATCC 13124. The antigenic component of the exoproteome of this strain has also been identified. Most of the extracellular proteins were predicted to be involved in carbohydrate transport and metabolism (16%) or cell envelope biogenesis or to be outer surface protein constituents (13%). More than 50% of the proteins were predictably secreted by either classical or nonclassical pathways. LipoP and TMHMM indicated that nine proteins were extracytoplasmic but cell associated. Immunization with recombinant ornithine carbamoyltransferase (cOTC) clearly resulted in protection against a direct challenge with C. perfringens organisms. A significant rise in IgG titers in response to recombinant cOTC was observed in mice, and IgG2a titers predominated over IgG1 titers (IgG2a/IgG1 ratio, 2). The proliferation of spleen lymphocytes in cOTC-immunized animals suggested a cellular immune response. There were significant increases in the levels of gamma interferon (IFN-?) and interleukin 2 (IL-2), suggesting a Th1 type immune response. PMID:20605988

Sengupta, Nabonita; Alam, Syed Imteyaz; Kumar, Bhoj; Kumar, Ravi Bhushan; Gautam, Vandana; Kumar, Subodh; Singh, Lokendra

2010-01-01

91

Characterization of Clostridium perfringens isolates from healthy turkeys and from turkeys with necrotic enteritis.  

PubMed

Clostridium perfringens is an important bacterial pathogen, especially in poultry, where it can lead to both subclinical and clinical disease. The aim of this study was to present data on pathological findings at outbreaks of necrotic enteritis (NE) in turkey production in Finland during the period from 1998 to 2012. Furthermore, C. perfringens isolates from healthy and diseased turkeys were characterized and their genetic diversity was investigated using pulsed-field gel electrophoresis (PFGE). Isolates (n = 212) from birds with necrotic gut lesions and from healthy flocks of 30 commercial turkey farms were characterized for the presence of cpa, cpb, iA, etx, cpb2, and cpe and netB genes. A total of 93 C. perfringens isolates, including 55 from birds with necrotic gut lesions and 38 from healthy birds from 13 different farms, were analyzed with PFGE. All contract turkey farmers (n = 48) of a turkey company that produces 99% of domestic turkey meat in Finland were interviewed about background information, management at the farm, and stress factors related to NE outbreaks. Pulsed-field gel electrophoresis analysis with SmaI restriction enzyme resulted in 30 PFGE patterns among the 92 C. perfringens isolates of high diversity. Out of all isolates, 212 (100%) were ?-toxin-positive and one isolate (0.5%) was both ?- and ?2 toxin-positive. Fourteen isolates (6.6%) were necrotic enteritis toxin B (NetB) positive; all were recovered from turkeys with NE. In none of the isolates obtained from healthy turkeys was the netB toxin identified. In conclusion, a high diversity of C. perfringens isolates from turkeys with different health status was shown. All isolates produced ? toxin, whereas only low percentages of isolates carried the netB toxin gene. The role of the netB toxin in NE in turkeys needs to be further investigated. PMID:23776261

Lyhs, U; Perko-Mäkelä, P; Kallio, H; Brockmann, A; Heinikainen, S; Tuuri, H; Pedersen, K

2013-07-01

92

Characterization of Genes Encoding for Acquired Bacitracin Resistance in Clostridium perfringens  

PubMed Central

Phenotypic bacitracin resistance has been reported in Clostridium perfringens. However, the genes responsible for the resistance have not yet been characterized. Ninety-nine C. perfringens isolates recovered from broilers and turkeys were tested for phenotypic bacitracin resistance. Bacitracin MIC90 (>256 µg/ml) was identical for both turkey and chicken isolates; whereas MIC50 was higher in turkey isolates (6 µg/ml) than in chicken isolates (3 µg/ml). Twenty-four of the 99 isolates showed high-level bacitracin resistance (MIC breakpoint >256 µg/ml) and the genes encoding for this resistance were characterized in C. perfringens c1261_A strain using primer walking. Sequence analysis and percentages of amino acid identity revealed putative genes encoding for both an ABC transporter and an overproduced undecaprenol kinase in C. perfringens c1261_A strain. These two mechanisms were shown to be both encoded by the putative bcrABD operon under the control of a regulatory gene, bcrR. Efflux pump inhibitor thioridazine was shown to increase significantly the susceptibility of strain c1261_A to bacitracin. Upstream and downstream from the bcr cluster was an IS1216-like element, which may play a role in the dissemination of this resistance determinant. Pulsed-field gel electrophoresis with prior double digestion with I-CeuI/MluI enzymes followed by hybridization analyses revealed that the bacitracin resistance genes bcrABDR were located on the chromosome. Semi-quantitative RT-PCR demonstrated that this gene cluster is expressed under bacitracin stress. Microarray analysis revealed the presence of these genes in all bacitracin resistant strains. This study reports the discovery of genes encoding for a putative ABC transporter and an overproduced undecaprenol kinase associated with high-level bacitracin resistance in C. perfringens isolates from turkeys and broiler chickens. PMID:22970221

Charlebois, Audrey; Jalbert, Louis-Alexandre; Harel, Josee; Masson, Luke; Archambault, Marie

2012-01-01

93

Lyophilized Carnobacterium divergens AS7 bacteriocin preparation improves performance of broiler chickens challenged with Clostridium perfringens.  

PubMed

The present study aimed to investigate the effects of Carnobacterium divergens AS7 bacteriocin (divercin AS7) on growth performance, digestibility, fermentation processes, selected microbial populations, and histomorphology in broiler chickens challenged with a mixture of 3 Clostridium perfringens isolates. In total, 480 one-day-old male Ross 308 chicks were randomly assigned to 4 experimental groups (12 replicate pens of 10 birds per treatment). The diets were either nonsupplemented or supplemented with a lyophilized preparation of divercin AS7. On d 18, 19, and 20, half of the birds were challenged twice a day with the C. perfringens mixture. The C. perfringens challenge did not influence broiler BW gain but impaired feed conversion ratio from d 29 to 42 (P=0.023) and throughout the experimental period (P=0.038). Moreover, the C. perfringens challenge resulted in decreased pH levels of crop, gizzard, and ileum contents (P<0.05) and reduced the numbers of lactic acid bacteria in the ceca (P=0.01). Divercin supplementation decreased broiler feed intake from d 14 to 28 (P=0.001) but increased BW gain from d 29 to 42 (P=0.048). The divercin supplementation increased the AMEn level (P=0.015) and reduced digesta pH in crop and ileum (P=0.004 and P=0.042, respectively), but of nonchallenged birds only. Divercin supplementation, moreover, increased gizzard lactate concentrations (P=0.003). The crop concentrations of lactate and succinate and the ileum concentration of lactate were increased by divercin supplementation (P=0.005, P=0.027, and P=0.002, respectively) and C. perfringens challenge (P=0.034, P=0.053, and P=0.0002, respectively). Divercin supplementation decreased villus heights (P=0.0006) and crypt depths (P=0.044) in noninfected birds, whereas in challenged birds, villus heights (P<0.0001) were increased. In conclusion, the present study demonstrated a very complex response pattern of broilers exposed to C. perfringens challenge and dietary divercin AS7 supplementation, but it indicated that divercin AS7 may partly counterbalance the negative effects associated with C. perfringens. PMID:22802184

Józefiak, D; Sip, A; Rutkowski, A; Rawski, M; Kaczmarek, S; Wo?u?-Cholewa, M; Engberg, R M; Højberg, O

2012-08-01

94

Genetic diversity of Clostridium perfringens type A isolates from animals, food poisoning outbreaks and sludge  

PubMed Central

Background Clostridium perfringens, a serious pathogen, causes enteric diseases in domestic animals and food poisoning in humans. The epidemiological relationship between C. perfringens isolates from the same source has previously been investigated chiefly by pulsed-field gel electrophoresis (PFGE). In this study the genetic diversity of C. perfringens isolated from various animals, from food poisoning outbreaks and from sludge was investigated. Results We used PFGE to examine the genetic diversity of 95 C. perfringens type A isolates from eight different sources. The isolates were also examined for the presence of the beta2 toxin gene (cpb2) and the enterotoxin gene (cpe). The cpb2 gene from the 28 cpb2-positive isolates was also partially sequenced (519 bp, corresponding to positions 188 to 706 in the consensus cpb2 sequence). The results of PFGE revealed a wide genetic diversity among the C. perfringens type A isolates. The genetic relatedness of the isolates ranged from 58 to 100% and 56 distinct PFGE types were identified. Almost all clusters with similar patterns comprised isolates with a known epidemiological correlation. Most of the isolates from pig, horse and sheep carried the cpb2 gene. All isolates originating from food poisoning outbreaks carried the cpe gene and three of these also carried cpb2. Two evolutionary different populations were identified by sequence analysis of the partially sequenced cpb2 genes from our study and cpb2 sequences previously deposited in GenBank. Conclusion As revealed by PFGE, there was a wide genetic diversity among C. perfringens isolates from different sources. Epidemiologically related isolates showed a high genetic similarity, as expected, while isolates with no obvious epidemiological relationship expressed a lesser degree of genetic similarity. The wide diversity revealed by PFGE was not reflected in the 16S rRNA sequences, which had a considerable degree of sequence similarity. Sequence comparison of the partially sequenced cpb2 gene revealed two genetically different populations. This is to our knowledge the first study in which the genetic diversity of C. perfringens isolates both from different animals species, from food poisoning outbreaks and from sludge has been investigated. PMID:16737528

Johansson, Anders; Aspan, Anna; Bagge, Elisabeth; Baverud, Viveca; Engstrom, Bjorn E; Johansson, Karl-Erik

2006-01-01

95

Effects of Clostridium perfringens Alpha-Toxin (PLC) and Perfringolysin O (PFO) on Cytotoxicity to Macrophages, on Escape from the Phagosomes of Macrophages, and on Persistence of C. perfringens in Host Tissues  

Microsoft Academic Search

Clostridium perfringens is the most common cause of clostridial myonecrosis (gas gangrene). Polymorpho- nuclear cells (PMNs) appear to play only a minor role in preventing the onset of myonecrosis in a mouse animal model of the disease (unpublished results). However, the importance of macrophages in the host defense against C. perfringens infections is still unknown. Two membrane-active toxins produced by

David K. O'Brien; Stephen B. Melville

2004-01-01

96

Benthic distribution of sewage sludge indicated by Clostridium perfringens at a deep-ocean dump site  

SciTech Connect

Since 1986, sewage sludge from New York and northern New Jersey has been dumped 196 km off the coast of New Jersey at the Deep Water Municipal Sewage Sludge Disposal Site. This study determines the distribution of sludge contamination of the benthic environment in the area, by using Clostridium perfringens as an indicator. The counts of C. perfringens confirm a previous report that sewage sludge is reaching the ocean floor at the disposal site as a result of the sludge dumping. C. perfringes counts within the dump site and to the south and west of the dump site are considerably elevated compared to counts east of the site. The distribution pattern of C. perfringes is broadly consistent with the estimates of the sea floor area impacted in the most recent computer model. However, the area of maximum desposition of sludge may be slightly further north than predicted. Use of C. perfringens has proven to be an efficient and reliable method for tracing sewage contamination of deep ocean sediments. 18 refs., 4 figs., 3 tabs.

Hill, R.T.; Anikis, M.S.; Colwell, R.R. (Univ. of Maryland, Baltimore (United States)); Knight, I.T. (James Madison Univ., Harrisonburg, VA (United States))

1993-01-01

97

Rapid expansion of the physical and genetic map of the chromosome of Clostridium perfringens CPN50.  

PubMed Central

The physical map of the 3.6-megabase chromosome of Clostridium perfringens CPN50 was extended by positioning sites for the endonucleases SfiI and I-CeuI, and in parallel, the gene map was expanded by using a genome scanning strategy. This involved the cloning and sequencing of random chromosomal fragments, identification of the functions of the putative genes by database searches, and then hybridization analysis. The current gene map comprises almost 100 markers, many of which encode housekeeping functions while others are involved in sporulation or pathogenesis. Strikingly, most of the virulence genes were found to be confined to a 1,200-kb segment of the chromosome near oriC, while the pleiotropic regulatory locus, virRS, was situated toward the putative replication terminus. A comparison of the gene maps of three endospore-forming bacilli, C. perfringens, Clostridium beijerinckii, and Bacillus subtilis, revealed a similar order and distribution of key sporulation and heat shock genes which might reflect an ancient evolutionary relationship. PMID:7559358

Katayama, S; Dupuy, B; Garnier, T; Cole, S T

1995-01-01

98

Induction of potential protective immunity against enterotoxemia in calves by single or multiple recombinant Clostridium perfringens toxoids.  

PubMed

Cattle enterotoxemia caused by Clostridium perfringens toxins is a noncontagious, sporadic, and fatal disease characterized by sudden death. Strategies for controlling and preventing cattle enterotoxemia are based on systematic vaccination of herds with toxoids. Because the process of producing conventional clostridial vaccines is dangerous, expensive, and time-consuming, the prospect of recombinant toxoid vaccines against diseases caused by C. perfringens toxins is promising. In this study, nontoxic recombinant toxoids derived from ?-, ?- and ?-toxins of C. perfringens, namely, rCPA247-370 , rCPB and rEtxHP, respectively, were expressed in Escherichia coli. High levels of specific IgG antibodies and neutralizing antibodies against the toxins were detected in sera from calves vaccinated with either a single recombinant toxoid or a mixed cocktail of all three recombinant toxoids, indicating the potential of these recombinant toxoids to provide calves with protective immunity against enterotoxemia caused by C. perfringens. PMID:25197030

Jiang, Zhigang; De, Yanyan; Chang, Jitao; Wang, Fang; Yu, Li

2014-11-01

99

Synergistic effects of Clostridium perfringens enterotoxin and beta toxin in rabbit small intestinal loops.  

PubMed

The ability of Clostridium perfringens type C to cause human enteritis necroticans (EN) is attributed to beta toxin (CPB). However, many EN strains also express C. perfringens enterotoxin (CPE), suggesting that CPE could be another contributor to EN. Supporting this possibility, lysate supernatants from modified Duncan-Strong sporulation (MDS) medium cultures of three CPE-positive type C EN strains caused enteropathogenic effects in rabbit small intestinal loops, which is significant since CPE is produced only during sporulation and since C. perfringens can sporulate in the intestines. Consequently, CPE and CPB contributions to the enteropathogenic effects of MDS lysate supernatants of CPE-positive type C EN strain CN3758 were evaluated using isogenic cpb and cpe null mutants. While supernatants of wild-type CN3758 MDS lysates induced significant hemorrhagic lesions and luminal fluid accumulation, MDS lysate supernatants of the cpb and cpe mutants caused neither significant damage nor fluid accumulation. This attenuation was attributable to inactivating these toxin genes since complementing the cpe mutant or reversing the cpb mutation restored the enteropathogenic effects of MDS lysate supernatants. Confirming that both CPB and CPE are needed for the enteropathogenic effects of CN3758 MDS lysate supernatants, purified CPB and CPE at the same concentrations found in CN3758 MDS lysates also acted together synergistically in rabbit small intestinal loops; however, only higher doses of either purified toxin independently caused enteropathogenic effects. These findings provide the first evidence for potential synergistic toxin interactions during C. perfringens intestinal infections and support a possible role for CPE, as well as CPB, in some EN cases. PMID:24778117

Ma, Menglin; Gurjar, Abhijit; Theoret, James R; Garcia, Jorge P; Beingesser, Juliann; Freedman, John C; Fisher, Derek J; McClane, Bruce A; Uzal, Francisco A

2014-07-01

100

Clostridium perfringens type A enterotoxin (CPE): more than just explosive diarrhea.  

PubMed

The bacterial pathogen Clostridium perfringens is the most prolific toxin-producing species within the clostridial group. The toxins are responsible for a wide variety of human and veterinary diseases, many of which are lethal. C. perfringens type A strains are also associated with one of the most common forms of food-borne illness (FBI). The toxicosis results from the production and gastrointestinal absorption of a protein-enterotoxin known as CPE. The regulation, expression, and mechanism of action of CPE has been of considerable interest as the protein is unique. CPE expression is sporulation associated, although the mechanism of cpe-gene regulation is not fully elucidated. Cloning studies suggest the involvement of global regulators, but these have not been identified. Although very few type A strains are naturally enterotoxigenic, the cpe gene appears highly conserved. In FBI strains, cpe is chromosomally encoded; whereas in veterinary strains, cpe may be plasmid-encoded. Variation in cpe location suggests the involvement of transposable genetic element(s). CPE-like proteins are produced by some C. perfringens types C and D; and silent remnants of the cpe gene can be found in C. perfringens type E strains associated with the iota toxin gene. CPE has received attention for its biomedical importance. The toxin has been implicated in sudden infant death syndrome (SIDS) because of its superantigenic nature. CPE can destroy a wide variety of cell types both in vitro and in vivo, suggesting that it could have potential in the construction of immunotoxins to neoplastic cells. It is obvious that CPE is an interesting protein that deserves continued attention. PMID:8989513

Lindsay, J A

1996-01-01

101

Regulation of Sialidase Production in Clostridium perfringens by the Orphan Sensor Histidine Kinase ReeS  

PubMed Central

Clostridium perfringens is ubiquitous in nature and is often found as a commensal of the human and animal gastrointestinal tract. It is the primary etiological agent of clostridial myonecrosis, or gas gangrene, a serious infection that results in extensive tissue necrosis due to the action of one or more potent extracellular toxins. ?-toxin and perfringolysin O are the major extracellular toxins involved in the pathogenesis of gas gangrene, but histotoxic strains of C. perfringens, such as strain 13, also produce many degradative enzymes such as collagenases, hyaluronidases, sialidases and the cysteine protease, ?-clostripain. The production of many of these toxins is regulated either directly or indirectly by the global VirSR two-component signal transduction system. By isolating a chromosomal mutant and carrying out microarray analysis we have identified an orphan sensor histidine kinase, which we have named ReeS (regulator of extracellular enzymes sensor). Expression of the sialidase genes nanI and nanJ was down-regulated in a reeS mutant. Since complementation with the wild-type reeS gene restored nanI and nanJ expression to wild-type levels, as shown by quantitative reverse transcription-PCR and sialidase assays we concluded that ReeS positively regulates the expression of these sialidase genes. However, mutation of the reeS gene had no significant effect on virulence in the mouse myonecrosis model. Sialidase production in C. perfringens has been previously shown to be regulated by both the VirSR system and RevR. In this report, we have analyzed a previously unknown sensor histidine kinase, ReeS, and have shown that it also is involved in controlling the expression of sialidase genes, adding further complexity to the regulatory network that controls sialidase production in C. perfringens. PMID:24023881

Hiscox, Thomas J.; Harrison, Paul F.; Chakravorty, Anjana; Choo, Jocelyn M.; Ohtani, Kaori; Shimizu, Tohru

2013-01-01

102

Evidence That the Enterotoxin Gene Can Be Episomal in Clostridium perfringens Isolates Associated with Non-Food-Borne Human Gastrointestinal Diseases  

Microsoft Academic Search

Clostridium perfringens enterotoxin (CPE) is responsible for the diarrheal and cramping symptoms of human C. perfringens type A food poisoning. CPE-producing C. perfringens isolates have also recently been associated with several non-food-borne human gastrointestinal (GI) illnesses, including antibiotic-associated diarrhea and sporadic diarrhea. The current study has used restriction fragment length polymorphism (RFLP) and pulsed-field gel electrophoresis (PFGE) analyses to compare

RENEE E. COLLIE; BRUCE A. MCCLANE

1998-01-01

103

Comparison of media and methods for counting Clostridium perfringens in poultry meat and further-processed products.  

PubMed Central

A Most Probable Number (MPN) method involving Differential Reinforced Clostridial Medium followed by streaking on Willis & Hobbs medium was compared with direct plating of samples on Tryptose-Sulphite-Cycloserine agar without egg yolk, and two forms of Oleandomycin-Polymyxin-Sulphadiazine-Perfringens agar, one being prepared from a commercial, dehydrated product. With skin samples taken from chicken carcasses at different stages of processing, the three direct plating media gave similar counts of Cl. perfringens whereas results obtained with the MPN method were consistently lower. Although counts of Cl. perfringens from various further processed products were usually less than 10/g, the three plating media showed similar specificity for this organism. All media supported good growth of reference strains of Clostridium perfringens but it was found that physiologically similar species, including Cl. absonum, Cl. paraperfringens and Cl. perenne also grew uninhibited in these media and produced colonies identical with those of Cl. perfringens, thus indicating the need for confirmatory tests for Cl. perfringens when examining natural samples. PMID:6243326

Adams, B. W.; Mead, G. C.

1980-01-01

104

Identification of Novel Pathogenicity Loci in Clostridium perfringens Strains That Cause Avian Necrotic Enteritis  

PubMed Central

Type A Clostridium perfringens causes poultry necrotic enteritis (NE), an enteric disease of considerable economic importance, yet can also exist as a member of the normal intestinal microbiota. A recently discovered pore-forming toxin, NetB, is associated with pathogenesis in most, but not all, NE isolates. This finding suggested that NE-causing strains may possess other virulence gene(s) not present in commensal type A isolates. We used high-throughput sequencing (HTS) technologies to generate draft genome sequences of seven unrelated C. perfringens poultry NE isolates and one isolate from a healthy bird, and identified additional novel NE-associated genes by comparison with nine publicly available reference genomes. Thirty-one open reading frames (ORFs) were unique to all NE strains and formed the basis for three highly conserved NE-associated loci that we designated NELoc-1 (42 kb), NELoc-2 (11.2 kb) and NELoc-3 (5.6 kb). The largest locus, NELoc-1, consisted of netB and 36 additional genes, including those predicted to encode two leukocidins, an internalin-like protein and a ricin-domain protein. Pulsed-field gel electrophoresis (PFGE) and Southern blotting revealed that the NE strains each carried 2 to 5 large plasmids, and that NELoc-1 and -3 were localized on distinct plasmids of sizes ?85 and ?70 kb, respectively. Sequencing of the regions flanking these loci revealed similarity to previously characterized conjugative plasmids of C. perfringens. These results provide significant insight into the pathogenetic basis of poultry NE and are the first to demonstrate that netB resides in a large, plasmid-encoded locus. Our findings strongly suggest that poultry NE is caused by several novel virulence factors, whose genes are clustered on discrete pathogenicity loci, some of which are plasmid-borne. PMID:20532244

Parreira, Valeria R.; Marri, Pradeep R.; Rosey, Everett L.; Gong, Joshua; Songer, J. Glenn; Vedantam, Gayatri; Prescott, John F.

2010-01-01

105

The genome sequence and proteome of bacteriophage ?CPV1 virulent for Clostridium perfringens.  

PubMed

Application of bacteriophages and their lytic enzymes to control Clostridium perfringens is one potential approach to reduce the pathogen on poultry farms and in poultry-processing facilities. Bacteriophages lytic for C. perfringens were isolated from sewage, feces and broiler intestinal contents and ?CPV1, a virulent bacteriophage, was classified in the family Podoviridae. The purified virus had an icosahedral head and collar of approximately 42nm and 23nm in diameter, respectively, with a structurally complex tail of 37nm lengthwise and a basal plate of 30nm. The ?CPV1 double-stranded DNA genome was 16,747 base pairs with a GC composition of 30.5%. Twenty-two open reading frames (ORFs) coding for putative peptides containing 30 or more amino acid residues were identified and analyzed in the genome. Amino acid sequences of the predicted proteins from the ?CPV1 genome ORFs were compared with those from the NCBI database and potential functions of 12 proteins were predicted by sequence homology. Three putative proteins were similar to hypothetical proteins with unknown functions, whereas seven proteins did not have similarity with any known bacteriophage or bacterial proteins. Identified ORFs formed at least four genomic clusters that accounted for predicted proteins involved with replication of the viral DNA, its folding, production of structural components and lytic properties. One bacteriophage genome encoded lysin was predicted to share homology with N-acetylmuramoyl-l-alanine amidases and a second structural lysin was predicted to be a lysozyme-endopeptidase. These enzymes digest peptidoglycan of the bacterial cell wall and could be considered potential therapeutics to control C. perfringens. PMID:21144870

Volozhantsev, Nikolay V; Verevkin, Vladimir V; Bannov, Vasily A; Krasilnikova, Valentina M; Myakinina, Vera P; Zhilenkov, Eugeni L; Svetoch, Edward A; Stern, Norman J; Oakley, Brian B; Seal, Bruce S

2011-02-01

106

Synthesis of deoxyribonucleic acid, ribonucleic acid, and protein during sporulation of Clostridium perfringens.  

PubMed Central

The kinetics of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis as well as protein breakdown during sporulation by Clostridium perfringens were determined. Maximum levels of DNA and net RNA synthesis occurred 3 and 2 h, respectively, after inoculation of sporulation medium. The rate of RNA synthesis decreased as sporulation progressed. Deoxyadenosine increased uptake of [14C]uracil and [14C]thymine but depressed the level of sporulation and the formation of heat-resistant spores when added at concentrations above 100 mug/ml. Unlike Bacillus species, net protein synthesis, which was sensitive to chloramphenicol inhibition, continued during sporulation. The rate of protein breakdown during vegetative growth was 1%/h. During sporulation this rate increased to 4.7%/h. When added to sporulation medium at 0 time chloramphenicol reduced protein breakdown to 1%/h. If added at 3 h the rate decreased to 2.1%/h. The role of proteases in this process is discussed. PMID:173709

Labbe, R G; Duncan, C L

1976-01-01

107

Clostridium perfringens type A enterotoxin induces release of noradrenaline from the neurosecretory PC12 cell line.  

PubMed

Clostridium perfringens type A enterotoxin(500 ng/ml) induced extensive release of noradrenaline (1/3-2/3 of the total cell content) from PC12 cells in 2-4 min in the presence, but not the absence of extracellular Ca2+. Cells treated with toxin in the absence of Ca2+ released noradrenaline promptly on subsequent addition of Ca2+ to the medium. The amount of noradrenaline released depended on the concentrations of both Ca2+ and toxin in the medium (ED50, 0.3 mM and 420 ng/ml respectively). Ca2+ could be replaced by Ba2+ or Sr2+, and Mn2+ or Co2+, which are Ca2+ channel blockers, did not inhibit the release of the transmitter. These findings are discussed in relation to the systemic effects of enterotoxin. PMID:3579904

Ozutsumi, K; Sugimoto, N; Matsuda, M

1987-04-14

108

Immobilized Clostridium perfringens neuraminidase. Substrate cleavage and enzyme release during incubation.  

PubMed

Pure Clostridium perfringens neuraminidase was immobilized on Sepharose 4 B, azido-Sepharose 4 B and controlled pore glass (CPG)- glycophase using different coupling procedures. The immobilized enzyme showed increased stability under various conditions relative to the soluble enzyme. The low release of active enzyme from the supports under incubation conditions was quantitated using a highly sensitive radioactive assay. The activity of the immobilized enzyme was dependent on the nature of the support and the substrate. Activity decreased with increasing substrate molecular weight, but the enzyme showed improved cleavage with GD1a micelles and human erythrocytes, substrates having ordered surface properties. Uses of immobilized neuraminidase in biochemistry and cell biology are considered and evaluated relative to the measured release of enzyme from the supports reported and to the molecular size and organization of possible substrates. PMID:196995

Parker, T L; Corfield, A P; Veh, R W; Schauer, R

1977-07-01

109

Effect of Clostridium perfringens beta toxin on blood pressure of rats.  

PubMed

Guanethidine treatment or adrenal medullectomy significantly inhibited the elevation in blood pressure induced by Clostridium perfringens beta toxin, and the combination of the two drastically reduced the pressure rise, to less than 19% of that in control rats. When rats were pretreated with tetrodotoxin or hexamethonium, the toxin-evoked rise was significantly inhibited. Elevation in blood pressure induced by the toxin in spinal rats tended to be less than that in control rats. When investigated by a microscopical technique, arteriolar constriction in the mesenteric vasculature was observed after the blood pressure elevation induced by the toxin reached a maximum. Blood flow in the skin decreased with an increase in blood pressure following intravenous injection of the toxin. It is concluded that beta toxin acts on the autonomic nervous system and produces arterial constriction. PMID:6145086

Sakurai, J; Fujii, Y; Dezaki, K; Endo, K

1984-01-01

110

Purification and characterization of an extracellular alpha-amylase from Clostridium perfringens type A.  

PubMed Central

An alpha-amylase (EC 3.2.1.1) secreted by Clostridium perfringens NCTC 8679 type A was purified to homogeneity and characterized. It was isolated from concentrated cell-free culture medium by ion-exchange and gel permeation chromatography. The enzyme exhibited maximal activity at pH 6.5 and 30 degrees C without the presence of calcium. The pI of the enzyme was 4.75. The estimated molecular weight of the purified enzyme was 76 kDa. The purified enzyme was inactivated between 35 and 40 degrees C, which increased to between 45 and 50 degrees C in the presence of calcium (5 mM). The purified enzyme produced a mixture of oligosaccharides as major end products of starch hydrolysis, indicating alpha-amylase activity. PMID:7646015

Shih, N J; Labbé, R G

1995-01-01

111

A paracrystalline inclusion formed during sporulation of enterotoxin-producing strains of Clostridium perfringens type A.  

PubMed

A large paracrystalline inclusion is formed by certain strains of Clostridium perfringens type A during spore morphogenesis. In most cell thin sections, the inclusion appeared rod-shaped when sectioned at an angle perpendicular to its longer axis, and circular or oval-shaped when sectioned at an angle parallel to its longer axis. Measurements performed on electron micrographs of inclusions sectioned to reveal the rod shape indicated a fairly consistent thickness (width) of 192 +/- 23 nm. The length of the inclusions varied considerably with a maximum of approximately 2,120 nm being observed. Ultrastructurally, the inclusion was composed of closely packed, periodically spaced, parallel layers. Usually a single inclusion was randomly located in the cytoplasm of the cell. Two inclusions per cell were rarely observed. The inclusion was formed only by ent(+) strains of C. perfringens. Mutants of the ent(+) strain NCTC 8798 that were altered in their sporulating and enterotoxin-producing capacities and revertants of these mutants were tested for inclusion formation. The results indicate that, as with the ent(+) trait, a direct relationship exists between inclusion formation and spore formation. The synthesis of enterotoxin, formation of a morphologically distinct inclusion, and the initial deposition of discontinuous coat fragments around the forespore appear to be events closely related in time during spore morphogenesis. PMID:4350345

Duncan, C L; King, G J; Frieben, W R

1973-05-01

112

A Paracrystalline Inclusion Formed During Sporulation of Enterotoxin-Producing Strains of Clostridium perfringens Type A  

PubMed Central

A large paracrystalline inclusion is formed by certain strains of Clostridium perfringens type A during spore morphogenesis. In most cell thin sections, the inclusion appeared rod-shaped when sectioned at an angle perpendicular to its longer axis, and circular or oval-shaped when sectioned at an angle parallel to its longer axis. Measurements performed on electron micrographs of inclusions sectioned to reveal the rod shape indicated a fairly consistent thickness (width) of 192 ± 23 nm. The length of the inclusions varied considerably with a maximum of approximately 2,120 nm being observed. Ultrastructurally, the inclusion was composed of closely packed, periodically spaced, parallel layers. Usually a single inclusion was randomly located in the cytoplasm of the cell. Two inclusions per cell were rarely observed. The inclusion was formed only by ent+ strains of C. perfringens. Mutants of the ent+ strain NCTC 8798 that were altered in their sporulating and enterotoxin-producing capacities and revertants of these mutants were tested for inclusion formation. The results indicate that, as with the ent+ trait, a direct relationship exists between inclusion formation and spore formation. The synthesis of enterotoxin, formation of a morphologically distinct inclusion, and the initial deposition of discontinuous coat fragments around the forespore appear to be events closely related in time during spore morphogenesis. Images PMID:4350345

Duncan, Charles L.; King, Gretchen J.; Frieben, William R.

1973-01-01

113

Alpha toxin from Clostridium perfringens induces proinflammatory changes in endothelial cells.  

PubMed

Alpha toxin from Clostridium perfringens type A, a phospholipase C, has been implicated in many of the localized and systemic features of gas gangrene. We demonstrated that human endothelial cells synthesize two vasoactive lipids, platelet-activating factor (PAF) and prostacyclin, in response to alpha toxin treatment. The stimulated synthesis of PAF required the enzymatic activity of the toxin and subsequent protein kinase C activation. Alpha toxin-treated endothelial cells accumulated the products of the phospholipase C reaction, diacylglycerol and ceramide, and exhibited a decrease in the enzymatic precursors phosphatidylcholine and sphingomyelin. Furthermore, the temporal accumulation of PAF depended on the concentration of the toxin in the overlying medium and was blocked in the presence of a neutralizing antibody. The cultured endothelial cells also exhibited enhanced neutrophil adhesion in response to alpha toxin which was mediated through the PAF receptor and P-selectin. P-selectin expression by endothelial cells and extravascular neutrophil accumulation were also observed in tissue sections from alpha toxin-injected Sprague-Dawley rats. These endothelial cell-mediated processes are important in maintaining vascular homeostasis and, when activated in a dysregulated manner by C. perfringens alpha toxin, may contribute to localized and systemic manifestations of gas gangrene including enhanced vascular permeability, localized neutrophil accumulation, and myocardial dysfunction. PMID:9239403

Bunting, M; Lorant, D E; Bryant, A E; Zimmerman, G A; McIntyre, T M; Stevens, D L; Prescott, S M

1997-08-01

114

Alpha toxin from Clostridium perfringens induces proinflammatory changes in endothelial cells.  

PubMed Central

Alpha toxin from Clostridium perfringens type A, a phospholipase C, has been implicated in many of the localized and systemic features of gas gangrene. We demonstrated that human endothelial cells synthesize two vasoactive lipids, platelet-activating factor (PAF) and prostacyclin, in response to alpha toxin treatment. The stimulated synthesis of PAF required the enzymatic activity of the toxin and subsequent protein kinase C activation. Alpha toxin-treated endothelial cells accumulated the products of the phospholipase C reaction, diacylglycerol and ceramide, and exhibited a decrease in the enzymatic precursors phosphatidylcholine and sphingomyelin. Furthermore, the temporal accumulation of PAF depended on the concentration of the toxin in the overlying medium and was blocked in the presence of a neutralizing antibody. The cultured endothelial cells also exhibited enhanced neutrophil adhesion in response to alpha toxin which was mediated through the PAF receptor and P-selectin. P-selectin expression by endothelial cells and extravascular neutrophil accumulation were also observed in tissue sections from alpha toxin-injected Sprague-Dawley rats. These endothelial cell-mediated processes are important in maintaining vascular homeostasis and, when activated in a dysregulated manner by C. perfringens alpha toxin, may contribute to localized and systemic manifestations of gas gangrene including enhanced vascular permeability, localized neutrophil accumulation, and myocardial dysfunction. PMID:9239403

Bunting, M; Lorant, D E; Bryant, A E; Zimmerman, G A; McIntyre, T M; Stevens, D L; Prescott, S M

1997-01-01

115

Biochemistry and Physiology of the ? Class Carbonic Anhydrase (Cpb) from Clostridium perfringens Strain 13  

PubMed Central

The carbonic anhydrase (Cpb) from Clostridium perfringens strain 13, the only carbonic anhydrase encoded in the genome, was characterized both biochemically and physiologically. Heterologously produced and purified Cpb was shown to belong to the type I subclass of the ? class, the first ? class enzyme investigated from a strictly anaerobic species of the domain Bacteria. Kinetic analyses revealed a two-step, ping-pong, zinc-hydroxide mechanism of catalysis with Km and kcat/Km values of 3.1 mM CO2 and 4.8 × 106 s?1 M?1, respectively. Analyses of a cpb deletion mutant of C. perfringens strain HN13 showed that Cpb is strictly required for growth when cultured in semidefined medium and an atmosphere without CO2. The growth of the mutant was the same as that of the parent wild-type strain when cultured in nutrient-rich media with or without CO2 in the atmosphere, although elimination of glucose resulted in decreased production of acetate, propionate, and butyrate. The results suggest a role for Cpb in anaplerotic CO2 fixation reactions by supplying bicarbonate to carboxylases. Potential roles in competitive fitness are discussed. PMID:23475974

Kumar, R. Siva Sai; Hendrick, William; Correll, Jared B.; Patterson, Andrew D.; Melville, Stephen B.

2013-01-01

116

Comparative genomic hybridization analysis shows different epidemiology of chromosomal and plasmid-borne cpe-carrying Clostridium perfringens type A.  

PubMed

Clostridium perfringens, one of the most common causes of food poisonings, can carry the enterotoxin gene, cpe, in its chromosome or on a plasmid. C. perfringens food poisonings are more frequently caused by the chromosomal cpe-carrying strains, while the plasmid-borne cpe-positive genotypes are more commonly found in the human feces and environmental samples. Different tolerance to food processing conditions by the plasmid-borne and chromosomal cpe-carrying strains has been reported, but the reservoirs and contamination routes of enterotoxin-producing C. perfringens remain unknown. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three C. perfringens type A genomes was conducted to shed light on the epidemiology of C. perfringens food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains by comparing chromosomal and plasmid-borne cpe-positive and cpe-negative C. perfringens isolates from human, animal, environmental, and food samples. The chromosomal and plasmid-borne cpe-positive C. perfringens genotypes formed two distinct clusters. Variable genes were involved with myo-inositol, ethanolamine and cellobiose metabolism, suggesting a new epidemiological model for C. perfringens food poisonings. The CGH results were complemented with growth studies, which demonstrated different myo-inositol, ethanolamine, and cellobiose metabolism between the chromosomal and plasmid-borne cpe-carrying strains. These findings support a ubiquitous occurrence of the plasmid-borne cpe-positive strains and their adaptation to the mammalian intestine, whereas the chromosomal cpe-positive strains appear to have a narrow niche in environments containing degrading plant material. Thus the epidemiology of the food poisonings caused by two populations appears different, the plasmid-borne cpe-positive strains probably contaminating foods via humans and the chromosomal strains being connected to plant material. PMID:23094024

Lahti, Päivi; Lindström, Miia; Somervuo, Panu; Heikinheimo, Annamari; Korkeala, Hannu

2012-01-01

117

Comparative Genomic Hybridization Analysis Shows Different Epidemiology of Chromosomal and Plasmid-Borne cpe-Carrying Clostridium perfringens Type A  

PubMed Central

Clostridium perfringens, one of the most common causes of food poisonings, can carry the enterotoxin gene, cpe, in its chromosome or on a plasmid. C. perfringens food poisonings are more frequently caused by the chromosomal cpe-carrying strains, while the plasmid-borne cpe-positive genotypes are more commonly found in the human feces and environmental samples. Different tolerance to food processing conditions by the plasmid-borne and chromosomal cpe-carrying strains has been reported, but the reservoirs and contamination routes of enterotoxin-producing C. perfringens remain unknown. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three C. perfringens type A genomes was conducted to shed light on the epidemiology of C. perfringens food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains by comparing chromosomal and plasmid-borne cpe-positive and cpe-negative C. perfringens isolates from human, animal, environmental, and food samples. The chromosomal and plasmid-borne cpe-positive C. perfringens genotypes formed two distinct clusters. Variable genes were involved with myo-inositol, ethanolamine and cellobiose metabolism, suggesting a new epidemiological model for C. perfringens food poisonings. The CGH results were complemented with growth studies, which demonstrated different myo-inositol, ethanolamine, and cellobiose metabolism between the chromosomal and plasmid-borne cpe-carrying strains. These findings support a ubiquitous occurrence of the plasmid-borne cpe-positive strains and their adaptation to the mammalian intestine, whereas the chromosomal cpe-positive strains appear to have a narrow niche in environments containing degrading plant material. Thus the epidemiology of the food poisonings caused by two populations appears different, the plasmid-borne cpe-positive strains probably contaminating foods via humans and the chromosomal strains being connected to plant material. PMID:23094024

Lahti, Paivi; Lindstrom, Miia; Somervuo, Panu; Heikinheimo, Annamari; Korkeala, Hannu

2012-01-01

118

Global regulation of gene expression in response to cysteine availability in Clostridium perfringens  

PubMed Central

Background Cysteine has a crucial role in cellular physiology and its synthesis is tightly controlled due to its reactivity. However, little is known about the sulfur metabolism and its regulation in clostridia compared with other firmicutes. In Clostridium perfringens, the two-component system, VirR/VirS, controls the expression of the ubiG operon involved in methionine to cysteine conversion in addition to the expression of several toxin genes. The existence of links between the C. perfringens virulence regulon and sulfur metabolism prompted us to analyze this metabolism in more detail. Results We first performed a tentative reconstruction of sulfur metabolism in C. perfringens and correlated these data with the growth of strain 13 in the presence of various sulfur sources. Surprisingly, C. perfringens can convert cysteine to methionine by an atypical still uncharacterized pathway. We further compared the expression profiles of strain 13 after growth in the presence of cystine or homocysteine that corresponds to conditions of cysteine depletion. Among the 177 genes differentially expressed, we found genes involved in sulfur metabolism and controlled by premature termination of transcription via a cysteine specific T-box system (cysK-cysE, cysP1 and cysP2) or an S-box riboswitch (metK and metT). We also showed that the ubiG operon was submitted to a triple regulation by cysteine availability via a T-box system, by the VirR/VirS system via the VR-RNA and by the VirX regulatory RNA. In addition, we found that expression of pfoA (theta-toxin), nagL (one of the five genes encoding hyaluronidases) and genes involved in the maintenance of cell redox status was differentially expressed in response to cysteine availability. Finally, we showed that the expression of genes involved in [Fe-S] clusters biogenesis and of the ldh gene encoding the lactate dehydrogenase was induced during cysteine limitation. Conclusion Several key functions for the cellular physiology of this anaerobic bacterium were controlled in response to cysteine availability. While most of the genes involved in sulfur metabolism are regulated by premature termination of transcription, other still uncharacterized mechanisms of regulation participated in the induction of gene expression during cysteine starvation. PMID:20822510

2010-01-01

119

The Mycotoxin Deoxynivalenol Predisposes for the Development of Clostridium perfringens-Induced Necrotic Enteritis in Broiler Chickens  

PubMed Central

Both mycotoxin contamination of feed and Clostridium perfringens-induced necrotic enteritis have an increasing global economic impact on poultry production. Especially the Fusarium mycotoxin deoxynivalenol (DON) is a common feed contaminant. This study aimed at examining the predisposing effect of DON on the development of necrotic enteritis in broiler chickens. An experimental Clostridium perfringens infection study revealed that DON, at a contamination level of 3,000 to 4,000 µg/kg feed, increased the percentage of birds with subclinical necrotic enteritis from 20±2.6% to 47±3.0% (P<0.001). DON significantly reduced the transepithelial electrical resistance in duodenal segments (P<0.001) and decreased duodenal villus height (P?=?0.014) indicating intestinal barrier disruption and intestinal epithelial damage, respectively. This may lead to an increased permeability of the intestinal epithelium and decreased absorption of dietary proteins. Protein analysis of duodenal content indeed showed that DON contamination resulted in a significant increase in total protein concentration (P?=?0.023). Furthermore, DON had no effect on in vitro growth, alpha toxin production and netB toxin transcription of Clostridium perfringens. In conclusion, feed contamination with DON at concentrations below the European maximum guidance level of 5,000 µg/kg feed, is a predisposing factor for the development of necrotic enteritis in broilers. These results are associated with a negative effect of DON on the intestinal barrier function and increased intestinal protein availability, which may stimulate growth and toxin production of Clostridium perfringens. PMID:25268498

Antonissen, Gunther; Ducatelle, Richard; Haesebrouck, Freddy; Timbermont, Leen; Verlinden, Marc; Janssens, Geert Paul Jules; Eeckhaut, Venessa; Eeckhout, Mia; De Saeger, Sarah; Hessenberger, Sabine; Martel, An; Croubels, Siska

2014-01-01

120

Multimicrobial Sepsis Including Clostridium perfringens after Chemoembolization of a Single Liver Metastasis from Common Bile Duct Cancer  

Microsoft Academic Search

A 65-year-old woman underwent resection of a distal common bile duct carcinoma (Whipple’s procedure). Twelve months later a single hepatic metastasis was detected and a chemoembolization was performed. Immediately after chemoembolization the patient developed a multimicrobial sepsis including Clostridium perfringens. CT scans depicted pathognomonic signs of gas-containing abscess in the necrotic liver metastasis. She was subsequently treated with broad-spectrum antibiotics,

Florian Eckel; Christian Lersch; Wolfgang Huber; Wolfgang Weiss; Hermann Berger; Ewert Schulte-Frohlinde

2000-01-01

121

Distribution of sewage indicated by Clostridium perfringens at a deep-water disposal site after cessation of sewage disposal.  

PubMed Central

Clostridium perfringens, a marker of domestic sewage contamination, was enumerated in sediment samples obtained from the vicinity of the 106-Mile Site 1 month and 1 year after cessation of sewage disposal at this site. C. perfringens counts in sediments collected at the disposal site and from stations 26 nautical miles (ca. 48 km) and 50 nautical miles (ca. 92 km) to the southwest of the site were, in general, more than 10-fold higher than counts from an uncontaminated reference site. C. perfringens counts at the disposal site were not significantly different between 1992 and 1993, suggesting that sewage sludge had remained in the benthic environment at this site. At stations where C. perfringens counts were elevated (i.e., stations other than the reference station), counts were generally higher in the top 1 cm and decreased down to 5 cm. In some cases, C. perfringens counts in the bottom 4 or 5 cm showed a trend of higher counts in 1993 than in 1992, suggesting bioturbation. We conclude that widespread sludge contamination of the benthic environment has persisted for at least 1 year after cessation of ocean sewage disposal at the 106-Mile Site. PMID:8633872

Hill, R T; Straube, W L; Palmisano, A C; Gibson, S L; Colwell, R R

1996-01-01

122

Differential Responses of Cecal Microbiota to Fishmeal, Eimeria and Clostridium perfringens in a Necrotic Enteritis Challenge Model in Chickens  

PubMed Central

Clostridium perfringens causes enteric diseases in animals and humans. In poultry, avian-specific C. perfringens strains cause necrotic enteritis, an economically significant poultry disease that costs the global industry over $2 billion annually in losses and control measures. With removal of antibiotic growth promoters in some countries this disease appears to be on the rise. In experimental conditions used to study disease pathogenesis and potential control measures, reproduction of the disease relies on the use of predisposing factors such as Eimeria infection and the use of high protein diets, indicating complex mechanisms involved in the onset of necrotic enteritis. The mechanisms by which the predisposing factors contribute to disease progression are not well understood but it has been suggested that they may cause perturbations in the microbiota within the gastrointestinal tract. We inspected changes in cecal microbiota and short chain fatty acids (SCFA) induced by Eimeria and fishmeal, in birds challenged or not challenged with C. perfringens. C. perfringens challenge in the absence of predisposing factors did not cause significant changes in either the alpha or beta diversity of the microbiota nor in concentrations of SCFA. Moreover, there was no C. perfringens detected in the cecal microbiota 2 days post-challenge without the presence of predisposing factors. In contrast, both fishmeal and Eimeria caused significant changes in microbiota, seen in both alpha and beta diversity and also enabled C. perfringens to establish itself post challenge. Eimeria had its strongest influence on intestinal microbiota and SCFA when combined with fishmeal. Out of 6 SCFAs measured, including butyric acid, none were significantly influenced by C. perfringens, but their levels were strongly modified following the use of both predisposing factors. There was little overlap in the changes caused following Eimeria and fishmeal treatments, possibly indicating multiple routes for progressing towards clinical symptoms of necrotic enteritis. PMID:25167074

Rodgers, Nicholas; Swick, Robert A.; Moore, Robert J.

2014-01-01

123

Heterogeneity of enterotoxin-like protein extracted from spores fo Clostridium perfringens type A.  

PubMed

Enterotoxin-like protein was extracted from spores of three enterotoxin-positive and three enterotoxin-negative strains of Clostridium perfringens type A by urea/mercaptoethanol, alkaline mercaptoethanol and alkaline dithiothreitol. Disc immunoelectrophoresis demonstrated that three distinct enterotoxin-like proteins could be extracted. In 7% acrylamide gels, type I, type II, and type III enterotoxinlike proteins had relative mobilities of 0.52, 0.63, and 0.73 respectively. In contrast to disc immunoelectrophoresis, immunoelectrophoresis in agar gel demonstrated identical electrophoretic properties for the various entertoxin-like proteins. Immunoelectrofocusing experiments gave isoelectric points of 4.43, 4.43, 4.36, and 4.52 for purified entertoxin and type I, type II, and type III enterotoxin-like proteins respectively. Ferguson plots (i.e., log relative mobility versus acrylamide concentration) yielded nonparallel lines which intersected at a nonsieving concentration of acrylamide indicating that the various species of enterotoxin-like protein differed in size. Estimation of the molecular weight of purified enterotoxin and the three species of enterotoxin-like protein was done by comparing the slopes obtained in Ferguson plots with those obtained using proteins of a known molecular weight. Molecular weights of 38000, 36500, 23000, and 15400 were obtained for purified enterotoxin, type I, type II, and type III enterotoxin-like protein respectively. Collectively, the evidence indicates that fractionation of the different species of enterotoxin-like protein was due primarily to differences in their size, and that different forms of enterotoxin-like protein can be extracted from spores of different strains of C. perfringens type A. PMID:172332

Frieben, W R; Duncan, C L

1975-07-01

124

Structural and Functional Analysis of the Pore-Forming Toxin NetB from Clostridium perfringens  

PubMed Central

ABSTRACT Clostridium perfringens is an anaerobic bacterium that causes numerous important human and animal diseases, primarily as a result of its ability to produce many different protein toxins. In chickens, C. perfringens causes necrotic enteritis, a disease of economic importance to the worldwide poultry industry. The secreted pore-forming toxin NetB is a key virulence factor in the pathogenesis of avian necrotic enteritis and is similar to alpha-hemolysin, a ?-barrel pore-forming toxin from Staphylococcus aureus. To address the molecular mechanisms underlying NetB-mediated tissue damage, we determined the crystal structure of the monomeric form of NetB to 1.8 Å. Structural comparisons with other members of the alpha-hemolysin family revealed significant differences in the conformation of the membrane binding domain. These data suggested that NetB may recognize different membrane receptors or use a different mechanism for membrane-protein interactions. Consistent with this idea, electrophysiological experiments with planar lipid bilayers revealed that NetB formed pores with much larger single-channel conductance than alpha-hemolysin. Channel conductance varied with phospholipid net charge. Furthermore, NetB differed in its ion selectivity, preferring cations over anions. Using hemolysis as a screen, we carried out a random-mutagenesis study that identified several residues that are critical for NetB-induced cell lysis. Mapping of these residues onto the crystal structure revealed that they were clustered in regions predicted to be required for oligomerization or membrane binding. Together these data provide an insight into the mechanism of NetB-mediated pore formation and will contribute to our understanding of the mode of action of this important toxin. PMID:23386432

Yan, Xu-Xia; Porter, Corrine J.; Hardy, Simon P.; Steer, David; Smith, A. Ian; Quinsey, Noelene S.; Hughes, Victoria; Cheung, Jackie K.; Keyburn, Anthony L.; Kaldhusdal, Magne; Moore, Robert J.; Bannam, Trudi L.; Whisstock, James C.; Rood, Julian I.

2013-01-01

125

Evaluation of PCR and DNA sequencing for direct detection of Clostridium perfringens in the intestinal tract of broilers.  

PubMed

The aim of this investigation was to determine the presence of the opportunistic pathogen Clostridium perfringens by PCR and DNA sequencing, without previous cultivation. This methodology was then used to investigate how C. perfringens was affected by different preventive measures, such as ionophores and feed additives, for necrotic enteritis in broilers chickens. DNA was extracted from the intestinal content or intestinal tissue by DNA extraction kits. Detection limits for 16S rRNA, alpha-toxin, and cpb2 PCR gene targets were approximately 1 x 10(3), 5 x 10(4), and 1 x 10(6) cells per g of intestinal content or tissue, respectively, as determined with samples spiked with C. perfringens. The method was evaluated with samples from single conventional broilers or from pools of six birds of experimentally reared broilers. Conventional chickens, raised with salinomycin in their feed, showed reduced numbers of C. perfringens-positive samples (P < 0.05) for all three PCR tests. With respect to cpb2, a tendency to detect more samples as positive for C. perfringens was observed with increasing age. The addition of sodium butyrate and lactic acid in the feed for experimental birds had a minor effect (P < 0.10) on positive samples, as detected with the 16S rRNA PCR. For experimental birds fed whole wheat, only three out of six pools of six birds allowed detection of C. perfringens by the 16S rRNA PCR, compared to five for the untreated controls or the Avilamycin- or prebiotic-treated birds. All 16S rRNA partial gene sequences obtained were identical and were 99.5% similar to the rrnB gene of the type strain of C. perfringens. Two types of the partial cpb2 gene sequence were detected with a similarity of 93%. One type was translated into protein, whereas a stop codon was found in the other type. Both types were located in the "atypical" phylogenetic group of the cpb2 gene sequences. The PCR test, based on extraction of DNA from intestinal content, provided rapid screening of poultry for C. perfringens without the need to have access to facilities in order to immediately cultivate and identify bacteria at the location of sampling. Further work is suggested to determine the relationship between the degree of necrotic enteritis, the actual level of C. perfringens in the animal, and the detection achieved by PCR. PMID:19848086

Henriksen, Maya; Bisgaard, Magne; Francesch, Maria; Gabriel, Irene; Christensen, Henrik

2009-09-01

126

Cooling rate effect on outgrowth of Clostridium perfringens in cooked, ready-to-eat turkey breast roasts.  

PubMed

The potential for Clostridium perfringens spores to germinate and grow in cooked, ready-to-eat turkey products was evaluated to determine a safe cooling rate within the critical temperatures of 48.9 C (120 F) through 12.8 C (55 F). Raw turkey deli breast roasts were inoculated with a cocktail of C. perfringens spores (NCTC 8238, NCTC 8239, and NCTC 10388) and cooked in a steam oven to an internal temperature of 72 C. The sample roasts were then cooled through the critical cooling range at rates yielding cooling times of 6, 8, and 10 h. Turkey roasts were analyzed for spore growth and multiplication using tryptose-sulfite-cycloserine agar and anaerobic incubation at 37 C for 48 h. Cooling times of 6 and 8 h showed no proliferation of C. perfringens that would violate the USDA/Food Safety Inspection Service safe cooling standard criteria, which would allow no more than a 1 log10 multiplication between 48.9 and 12.8 C. A 9.6-h cooling period between the designated temperatures at a 95% confidence interval was determined to be adequate for nonproliferation of C. perfringens. On the other hand, a 95% tolerance interval would be more stringent in that it suggests no more than an 8.9-h cooling period. Tolerance intervals required that 95% of all our observations did not exceed the limit of 1 log10 increase in C. perfringens. This study indicated that in cooked, ready-to-eat turkey deli breasts, a cooling period between 48.9 C (120 F) and 12.8 C (55 F) of no greater than 8.9 h should be utilized to prevent possible C. perfringens foodborne outbreaks. PMID:11441851

Steele, F M; Wright, K H

2001-06-01

127

Effect of phosphate and meat (pork) types on the germination and outgrowth of Clostridium perfringens spores during abusive chilling.  

PubMed

The effect of phosphate blends and pork meat type (pale, soft, and exudative [PSE]; normal; and dark, firm, and dry [DFD]) on the germination and outgrowth of Clostridium perfringens during abusive exponential chilling times was evaluated. Two phosphates were used: tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate (SAPP; from two different sources, SAPP(1) and SAPP(2)). The pork loins representing each meat type were ground (1/8-in. [0.3-cm] plate), and one of the three phosphate blends (SAPP(1)+SAPP(2), TSPP+SAPP(1), or TSPP+SAPP(2)) was added (0.3% total, equal proportions of 0.15% each type) with salt (1.0%). The pork was then mixed with a three-strain C. perfringens spore cocktail to obtain a final concentration of ca. 2.0 to 2.5 log spores per g. The inoculated product was heat shocked for 20 min at 75 degrees C and chilled exponentially from 54.4 to 4 degrees C in a period of 6.5, 9, 12, 15, 18, or 21 h. In control samples (PSE, normal, and DFD), the increase in C. perfringens population was <1 log CFU/g within the 6.5-h chilling period, and longer chilling times resulted in greater increases. C. perfringens population increases of 5.95, 4.73, and 5.95 log CFU/g of meat were observed in normal, PSE, and DFD pork, respectively, during the 21-h abusive chilling period. The combination of SAPP(1)+SAPP(2) was more effective than the other treatments for inhibiting C. perfringens. The types of phosphate and their blends and the meat type affected the germination and outgrowth of C. perfringens spores in cooked pork during abusive chilling periods. PMID:20501039

Singh, Aikansh; Korasapati, Nageswara Rao; Juneja, Vijay K; Thippareddi, Harshavardhan

2010-05-01

128

Effect of cysteine modifications on the activity of the 'small' Clostridium perfringens sialidase.  

PubMed

The 'small' (43 kDa) sialidase of Clostridium perfringens is inhibited by low concentrations of mercury ions. For the investigation of possible functional roles of the enzyme's four cysteine residues at the amino acid positions 2, 282, 333 and 349, they were separately altered to serine by site-directed mutagenesis. The four mutant sialidases expressed in E. coli and purified by metal chelate chromatography were markedly reduced in specific activity when compared to the wild-type enzyme but with the exception of C282S exhibited similar K(M)-values indicating an unchanged mode of substrate binding. The substrate specificity was also conserved for C2S, C282S, and C333S. Only the C349S sialidase exhibited a higher relative activity with colominic acid and the alpha2,6-linked sialic acid of sialyllactose compared to the alpha2,3-linked isomer than the other mutants. Chemical modifications with the thiol-blocking reagents N-ethylmaleimide (NEM), p-chloromercuribenzoate (pCMB) and HgCl2 had little effect on the C282S sialidase, e.g., 6% inhibition by 5 mM NEM compared to reductions in activity between 65 and 90% for the wild-type and other mutant enzymes, supporting the idea that among the enzyme's cysteines, Cys-282 has the highest structural or functional significance. The results also explain the higher mercury tolerance of Salmonella typhimurium and Clostridium tertium sialidases, which have the positions equivalent to Cys-282 altered to Val and Thr, respectively, indicating that the thiol group of Cys-282, despite being situated near the active site, is not involved in catalysis. PMID:9870352

Kruse, S; Pommerencke, J; Kleineidam, R G; Roggentin, P; Schauer, R

1998-08-01

129

Clostridium perfringens Iota Toxin: Binding Studies and Characterization of Cell Surface Receptor by Fluorescence-Activated Cytometry  

PubMed Central

The binding characteristics of iota toxin, a binary enterotoxin produced by Clostridium perfringens type E, were studied by fluorescence-activated cytometry. The proteolytically activated binding component of iota toxin, iota b (Ib), bound to various cell types when incubated at 4, 25, or 37°C for 10 min. The binding of Ib was inhibited by antisera against C. perfringens type E or Clostridium spiroforme culture supernatants, but not C. perfringens types C or D. Pretreatment of Vero cells with glycosidases or lectins did not affect Ib interactions, while pronase effectively prevented Ib binding to the cell surface. The Ib protomer (Ibp) bound to the cell surface, but trypsinization of Ibp was necessary for docking of the ADP-ribosylating component, iota a (Ia). Ia attached to cell-bound Ib within 10 min at 37°C, but surface levels of Ia decreased 90% after 30 min and were undetectable by 60 min. Detectable surface levels of Ib also diminished over time, and Western blot analysis suggested internalization or embedment of Ib into the membrane. PMID:10816501

Stiles, Bradley G.; Hale, Martha L.; Marvaud, Jean-Christophe; Popoff, Michel R.

2000-01-01

130

Inhibition of Clostridium perfringens by a Novel Strain of Bacillus subtilis Isolated from the Gastrointestinal Tracts of Healthy Chickens  

PubMed Central

The objectives of this study were to isolate beneficial strains of microorganisms from the gastrointestinal tracts of healthy chickens and to screen them against Clostridium perfringens, a causative agent of necrotic enteritis in poultry. One of the bacteria isolated, a strain of Bacillus subtilis, was found to possess an anticlostridial factor that could inhibit the C. perfringens ATCC 13124 used in this study. The anticlostridial factor produced by B. subtilis PB6 was found to be fully or partially inactivated in the presence of pronase, trypsin, and pepsin. In contrast, the antimicrobial activity of the anticlostridial factor was not affected by treatment at 100 or 121°C or by treatment with any of the organic solvents used in the study. The optimum growth temperature and optimum pH for production of the anticlostridial factor were 37°C and 6.20, respectively. Using the mass spectroscopy-mass spectroscopy technique, the apparent molecular mass of the anticlostridial factor was estimated to be in the range from 960 to 983 Da. In terms of the antimicrobial spectrum, the anticlostridial factor was inhibitory toward various strains of C. perfringens implicated in necrotic enteritis in poultry, Clostridium difficile, Streptococcus pneumoniae, Campylobacter jejuni, and Campylobacter coli. PMID:16085801

Teo, Alex Yeow-Lim; Tan, Hai-Meng

2005-01-01

131

The p38 MAPK and JNK Pathways Protect Host Cells against Clostridium perfringens Beta-Toxin  

PubMed Central

Clostridium perfringens beta-toxin is an important agent of necrotic enteritis and enterotoxemia. Beta-toxin is a pore-forming toxin (PFT) that causes cytotoxicity. Two mitogen-activated protein kinase (MAPK) pathways (p38 and c-Jun N-terminal kinase [JNK]-like) provide cellular defense against various stresses. To investigate the role of the MAPK pathways in the toxic effect of beta-toxin, we examined cytotoxicity in five cell lines. Beta-toxin induced cytotoxicity in cells in the following order: THP-1 = U937 > HL-60 > BALL-1 = MOLT-4. In THP-1 cells, beta-toxin formed oligomers on lipid rafts in membranes and induced the efflux of K+ from THP-1 cells in a dose- and time-dependent manner. The phosphorylation of p38 MAPK and JNK occurred in response to an attack by beta-toxin. p38 MAPK (SB203580) and JNK (SP600125) inhibitors enhanced toxin-induced cell death. Incubation in K+-free medium intensified p38 MAPK activation and cell death induced by the toxin, while incubation in K+-high medium prevented those effects. While streptolysin O (SLO) reportedly activates p38 MAPK via reactive oxygen species (ROS), we showed that this pathway did not play a major role in p38 phosphorylation in beta-toxin-treated cells. Therefore, we propose that beta-toxin induces activation of the MAPK pathway to promote host cell survival. PMID:23876806

Shibutani, Masahiro; Seike, Soshi; Yonezaki, Mami; Takagishi, Teruhisa; Oda, Masataka; Kobayashi, Keiko; Sakurai, Jun

2013-01-01

132

Production and characterization of monoclonal antibodies against Clostridium perfringens type A enterotoxin.  

PubMed Central

Hybridomas secreting monoclonal antibodies (MABs) specific for Clostridium perfringens type A enterotoxin were produced by fusion of P3X63Ag8.653 myeloma cells with spleen cells from BALB/c mice immunized with purified enterotoxin. Wells containing hybridomas secreting immunoglobulin G (IgG) antibodies against enterotoxin were specifically identified by an indirect enzyme-linked immunosorbent assay (ELISA), and 10 ELISA-positive hybridomas were selected and cloned twice by limiting dilution. All 10 hybridomas produced MABs containing immunoglobulin G1 heavy chains and kappa (kappa) light chains. These hybridomas were then grown as ascitic tumors in mice, and MABs were purified from the ascites fluids with DEAE Affi-gel blue. The specificity of the MABs for enterotoxin was demonstrated by immunoblotting and ELISA. Competitive radioimmunoassay with 125I-MABs suggests that these MABs recognized at least four epitopes on the enterotoxin molecule. The enterotoxin-neutralizing ability of MABs from both hybridoma culture supernatants and ascites fluids was assessed by using a 3H-nucleotide-release Vero (African green monkey kidney) cell assay. Only 2 of the 10 hybridomas produced MABs which completely (greater than 90%) neutralized the biologic activity of enterotoxin. Preincubation of 125I-enterotoxin with MABs demonstrated that MAB neutralizing ability correlated with MAB-specific inhibition of specific binding of enterotoxin to intestinal brush border membranes. Images PMID:2865210

Wnek, A P; Strouse, R J; McClane, B A

1985-01-01

133

Clostridium perfringens type A: in vitro system for sporulation and enterotoxin synthesis.  

PubMed Central

Polysomes were isolated from an enterotoxigenic strain of Clostridium perfringens during vegetative growth and at 1-h intervals after transfer into Duncan-Strong sporulation medium. During vegetative growth, about 67% of the ribosomes were in polysomal complexes. This proportion decreased to about 20% during the first 2 h in sporulation medium and then gradually increased to a maximum of 45% at 6 h. Ribosomes isolated from cells in vegetative or in sporulation phase could equally translate vegetative, sporulation, and natural viral R17 messenger ribonucleic acid with either vegetative or sporulation initiation factors. When polysomes were allowed to complete their nascent chains with labeled amino acids in vitro, most of the polypeptides synthesized by the vegetative phase and by the sporulation phase polysomes appeared to be identical. There were, however, notable differences upon further investigation. Specifically, when antiserum against the enterotoxin was reacted with the completed polypeptides, no counts were precipitated from the vegetative products. On the other hand, up to 12% of the total labeled protein was precipitated from the products obtained with the sporulation phase polysomes. Upon electrophoresis on sodium dodecyl sulfate, the putative enterotoxin synthesized in vitro ran as a major band with a molecular weight of 35,000, and as two minor bands with molecular weights of 17,000 and 52,000, respectively. Images PMID:6252194

Smith, W P; McDonel, J L

1980-01-01

134

Evidence for stable messenger ribonucleic acid during sporulation and enterotoxin synthesis by Clostridium perfringens type A.  

PubMed Central

Stable messenger ribonucleic acid (mRNA) was shown to be involved in both enterotoxin synthesis and synthesis of other spore coat proteins in Clostridium perfringens. When used at a concentration that inhibited [14C]uracil incorporation, rifampin, a specific inhibitor of deoxyribonucleic acid-dependent RNA polymerase, prevented incorporation of a mixture of labeled amnoo acids by 3-h sporulating cells. At that time, enterotoxin protein was first detectable and cells were primarily at stage II or III of sporulation. When rifampin or streptolydigin was added to 5-h sporulating cells, which were primarily at stage IV or V and had significant toxin levels, incorporation of labeled amino acids continued through 30 min despite its presence. Rifampin also failed to prevent the specific synthesis of enterotoxin, a structural protein of the spore coat. The half-life of enterotoxin RNA was estimated to be at least 58 min. When cell extracts from 5-h sporulating cells that had been exposed to 3H-labeled amino acids for 10 min were subjected to electrophoresis on polyacrylamide gels and the gels were subsequently analyzed for radioactivity, two major peaks of radioactivity were obtained. The two peaks corresponded to enterotoxin and another spore coat protein(s). Similar results were obtained when the cells had been preincubated for 60 min with rifampin before label addition, indicating the functioning of stable mRNA. PMID:190209

Labbe, R G; Duncan, C L

1977-01-01

135

Inactivation of Clostridium perfringens Type A Spores at Ultrahigh Temperatures1  

PubMed Central

The inactivation of Clostridium perfringens type A spores (three strains of different heat resistances) at ultrahigh temperatures was studied. Aqueous spore suspensions were heated at 85 to 135 C by the capillary tube method. When survivors were enumerated on the standard plating medium, the spores appeared to have been rapidly inactivated at temperatures above 100 C. The addition of lysozyme to the plating medium did not affect the recovery of spores surviving the early stages of heating, but lysozyme was required for maximal recovery of spores surviving extended heat treatments. The percentage of survivors requiring lysozyme for colony formation increased greatly with longer exposure times or increasing treatment temperature. Time-survivor curves indicated that each spore suspension was heterogeneous with respect to the heat resistance of spore outgrowth system or in the sensitivity of the spores to lysozyme. Recovery of survivors on the lysozyme containing medium revealed greater heat resistance for one strain than has been reported for spores of many mesophilic aerobes and anaerobes. The spores of all three strains were more resistant to heat inactivation when suspended in phosphate buffer, but a greater percentage of the survivors required lysozyme for colony formation. PMID:4356457

Adams, D. M.

1973-01-01

136

Requirement for and Sensitivity to Lysozyme by Clostridium perfringens Spores Heated at Ultrahigh Temperatures1  

PubMed Central

The requirement of ultrahigh temperature (UHT)-treated Clostridium perfringens spores for lysozyme and the sensitivity of heated and unheated spores to lysozyme were studied. The UHT-treated spores requiring lysozyme for germination and colony formation originated from only a small portion of the non-UHT-treated spore population. This raised a question of whether the requirement for lysozyme was natural to the spores or was induced by the UHT treatments. However, these spores did not require lysozyme for germination before UHT treatment, which confirmed that the requirement for lysozyme had been induced by the UHT treatment. Only 1 to 2% of the spores were naturally sensitive to lysozyme; therefore, the mere addition of lysozyme to the plating medium did not permit the enumeration of all survivors. Treatment of UHT-treated spores with ethylenediaminetetraacetate (EDTA) sensitized the spores to lysozyme and increased by 10- to 100-fold the number of survivors that were detected on a medium containing lysozyme. Under the heating conditions used, spores that were naturally sensitive to lysozyme and spores that required EDTA treatment were equally heat resistant. PMID:4363559

Adams, D. M.

1974-01-01

137

Investigating an outbreak of Clostridium perfringens gastroenteritis in a school using smartphone technology, London, March 2013.  

PubMed

On 22 March 2013, 150 of 1,255 students (13–17 years) and staff at a school in London reported gastrointestinal symptoms; onset peaked 8 to 12 hours after a lunch served in the school on 21 March. We performed a retrospective cohort study of all students and staff. We defined cases as school attenders on 20 and 21 March with onset of gastrointestinal symptoms between 20 and 23 March. We tested food, environmental and stool samples of cases for common pathogens and bacterial toxins. We administered an online questionnaire via email, encouraging the use of smartphones to respond, to measure risk of illness for food items eaten at school on 20 and 21 March. Survey response was 45%. Adjusted risk ratios were generated in a multivariable analysis. Those who ate chicken balti on 21 March were 19.3 times more likely to become ill (95% confidence interval: 7.3–50.9). Clostridium perfringens was detected in all 19 stool samples collected. Within eight school hours of its launch, 412 of 561 (73%) responders had completed the survey. Hygienic standards in the kitchen were satisfactory. The investigation was done rapidly due to smartphone technology and we recommend considering this technology in future outbreaks. PMID:24852955

Simone, B; Atchison, C; Ruiz, B; Greenop, P; Dave, J; Ready, D; Maguire, H; Walsh, B; Anderson, S

2014-01-01

138

Development and application of a method for counterselectable in-frame deletion in Clostridium perfringens.  

PubMed

Many pathogenic clostridial species produce toxins and enzymes. To facilitate genome-wide identification of virulence factors and biotechnological application of their useful products, we have developed a markerless in-frame deletion method for Clostridium perfringens which allows efficient counterselection and multiple-gene disruption. The system comprises a galKT gene disruptant and a suicide galK plasmid into which two fragments of a target gene for in-frame deletion are cloned. The system was shown to be accurate and simple by using it to disrupt the alpha-toxin gene of the organism. It was also used to construct of two different virulence-attenuated strains, ??1303 and HN1314: the former is a disruptant of the virRS operon, which regulates the expression of virulence factors, and the latter is a disruptant of the six genes encoding the ?, ?, and ? toxins; a clostripain-like protease; a 190-kDa secretory protein; and a putative cell wall lytic endopeptidase. Comparison of the two disruptants in terms of growth ability and the background levels of secreted proteins showed that HN1314 is more useful than ??1303 as a host for the large-scale production of recombinant proteins. PMID:21183644

Nariya, Hirofumi; Miyata, Shigeru; Suzuki, Motoo; Tamai, Eiji; Okabe, Akinobu

2011-02-01

139

Intestinal events and nutritional dynamics predispose Clostridium perfringens virulence in broilers.  

PubMed

Clostridium perfringensA (CPA) entering the gastrointestinal system depends on favorable conditions to develop and subsequently extend pathogenicity. Reduction in digestive dynamics progressing from the duodenum decreases lumen oxygen, leading to anaerobic conditions in the distal lumen that favor CPA. When nutritional support is concurrently provided, an expanding population threatens the mucosa. Dietary nonstarch polysaccharides that increase viscosity further impair oxygen transfer from the mucosa, improving the ability of CPA to thrive. Incompletion of feed digestion early in the small intestine along with endogenous N provide additional support for population expansion. Glucosidase versatility with mucin elicited by distal CPA concurrently erodes the villus unstirred water layer at the apex, providing access to underlying binding sites for colonization. Proteolytic destruction within the lamina propria supports colonization to create subclinical necrotic enteritis. Eventual vascular entry of CPA and toxins provides a portal path for instituting cholangiohepatitis. Liver condemnations from inspection detect acute flock infection compared with preceding marginal losses in nutrient absorption that decrease feed efficiency. Enterocyte lysis by coccidia enable CPA access to binding sites, thereby extending villus necrosis and further impairing feed conversion. Loss of BW and increased mortality follow as mucosa involvement proceeds. In practice, supplemental feed hemicellulases that reduce digesta viscosity minimize a favorable environment for CPA, while superimposing a combination of amylase, phytase, and protease avoids nutritional support. Physical dynamics of the small intestine together with characteristics of feed that modify digesta viscosity and nutritional availability are central to establishing transient CPA as a pathogen. PMID:25260526

Moran, Edwin T

2014-12-01

140

Clostridium perfringens and sulphite reducing clostridia densities in selected tropical Malaysian rivers.  

PubMed

Clostridium perfringens (CP) and sulphite reducing clostridia (SRC) densities in the Selangor River, Bernam River and Tengi River Canal were examined between April 2007 and January 2008. Water samples were taken from two or three locations along each river, using either depth-integration or grab sampling methods. The downstream sampling site of the Selangor River, Rantau Panjang, reported the highest arithmetic mean of CP and SRC densities (583.45 and 8,120.08 cfu/100 ml, respectively). Both CP and SRC densities in the Selangor River increased further downstream, but the reverse was true in the Bernam River. The SRC densities in these rivers were significantly different from each other (p < 0.05) when comparing upstream and downstream results, but CP densities were not significantly different (p > 0.05). SRC densities were significantly correlated (p < 0.05) in different locations along the Selangor River and the Bernam River. The CP densities did not show such pattern (p > 0.05). River discharge had no significant correlation with SRC or CP densities by study site (p > 0.05). Since the Selangor River has a denser human population along its banks, this study confirms CP as a suitable indicator of human fecal contamination. However, tracing CP distribution along the river is more difficult than SRC. To our knowledge, this is the first study of CP and SRC densities from Malaysian rivers. CP densities found in this study were within the range of general water bodies reported from other countries. PMID:23082563

Lee, Florence C H; Hakim, S L; Kamaluddin, M A; Thong, Kwai Lin

2012-01-01

141

Clostridium perfringens is not suitable for the indication of fecal pollution from ruminant wildlife but is associated with excreta from nonherbivorous animals and human sewage.  

PubMed

During a 3-year study, Clostridium perfringens was investigated in defined fecal sources from a temperate alluvial backwater area of a large river system. The results reveal that using C. perfringens as a conservative water quality indicator for total fecal pollution monitoring is no longer justified but suggest that it can be used as a tracer for excreta from nonherbivorous wildlife and human sewage. PMID:23747707

Vierheilig, J; Frick, C; Mayer, R E; Kirschner, A K T; Reischer, G H; Derx, J; Mach, R L; Sommer, R; Farnleitner, A H

2013-08-01

142

The effect of grapefruit extract and temperature abuse on growth of Clostridium perfringens from spore inocula in marinated, sous-vide chicken products  

Microsoft Academic Search

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag, marinated chicken breast that included additional 1.0% NaCl. The packages were processed to an internal temperature of 71.1 °C, ice chilled and stored at various temperatures. The total C. perfringens population was determined by plating diluted samples on tryptose–sulfite–cycloserine agar followed by anaerobic incubation for 48 h at 37 °C. At

Vijay K. Juneja; Xuetong Fan; Aida Peña-Ramos; Martha Diaz-Cinco; Ramon Pacheco-Aguilar

2006-01-01

143

Collagenase gene ( colA) is located in the 3?-flanking region of the perfringolysin O ( pfoA) locus in Clostridium perfringens  

Microsoft Academic Search

The 3?-flanking region of the ?-galactosidase gene (pbg), which is located downstream of the perfringolysin O gene (pfoA), and the 5?-flanking region of the collagenase gene (colA) of Clostridium perfringens strains NCTC8237 and 13, respectively, were analyzed. Southern analysis revealed that the colA gene is located 6.5 kb downstream of the pbg gene in the chromosome of C. perfringens. Sequence

Kaori Ohtani; Mayumi Bando; Tint Swe; Sayera Banu; Misari Oe; Hideo Hayashi; Tohru Shimizu

1997-01-01

144

Clostridium perfringens Is Not Suitable for the Indication of Fecal Pollution from Ruminant Wildlife but Is Associated with Excreta from Nonherbivorous Animals and Human Sewage  

PubMed Central

During a 3-year study, Clostridium perfringens was investigated in defined fecal sources from a temperate alluvial backwater area of a large river system. The results reveal that using C. perfringens as a conservative water quality indicator for total fecal pollution monitoring is no longer justified but suggest that it can be used as a tracer for excreta from nonherbivorous wildlife and human sewage. PMID:23747707

Vierheilig, J.; Frick, C.; Mayer, R. E.; Kirschner, A. K. T.; Reischer, G. H.; Derx, J.; Mach, R. L.; Farnleitner, A. H.

2013-01-01

145

Hemorrhagic enterocolitis and death in two felines (Panthera tigris altaica and Panthera leo) associated with Clostridium perfringens type A.  

PubMed

Severe hemorrhagic enterocolitis was observed in a Siberian tiger (Panthera tigris altaica) and a lion (Panthera leo). Both animals developed acute depression, anorexia, and bloody diarrhea several days before death. Small and large intestines were diffusely congested, edematous, necrotic, and filled with hemorrhagic fluid, and mesenteric lymph nodes were enlarged and congested. Pure and abundant growth of gram-positive bacilli was obtained in culture under anaerobic conditions from the livers of both felines. Identification of highly virulent Clostridium perfringens Type A was based on pathologic lesions, hemolytic patterns, morphologic structure, and polymerase chain reaction. Animal inoculation assays indicated that C. perfringens Type A played an important role in the pathogenesis of both felines. PMID:22779248

Zhang, Yanlong; Hou, Zhijun; Ma, Jianzhang

2012-06-01

146

Abilities of the mCP Agar Method and CRENAME Alpha Toxin-Specific Real-Time PCR Assay To Detect Clostridium perfringens Spores in Drinking Water  

PubMed Central

We first determined the analytical specificity and ubiquity (i.e., the ability to detect all or most strains) of a Clostridium perfringens-specific real-time PCR (rtPCR) assay based on the cpa gene (cpa rtPCR) by using a bacterial strain panel composed of C. perfringens and non-C. perfringens Clostridium strains. All non-C. perfringens Clostridium strains tested negative, whereas all C. perfringens strains tested positive with the cpa rtPCR, for an analytical specificity and ubiquity of 100%. The cpa rtPCR assay was then used to confirm the identity of 116 putative C. perfringens isolates recovered after filtration of water samples and culture on mCP agar. Colonies presenting discordant results between the phenotype on mCP agar and cpa rtPCR were identified by sequencing the 16S rRNA and cpa genes. Four mCP?/rtPCR+ colonies were identified as C. perfringens, whereas 3 mCP+/rtPCR? colonies were identified as non-C. perfringens. The cpa rtPCR was negative with all 51 non-C. perfringens strains and positive with 64 of 65 C. perfringens strains. Finally, we compared mCP agar and a CRENAME (concentration and recovery of microbial particles, extraction of nucleic acids, and molecular enrichment) procedure plus cpa rtPCR (CRENAME + cpa rtPCR) for their abilities to detect C. perfringens spores in drinking water. CRENAME + cpa rtPCR detected as few as one C. perfringens CFU per 100 ml of drinking water sample in less than 5 h, whereas mCP agar took at least 25 h to deliver results. CRENAME + cpa rtPCR also allows the simultaneous and sensitive detection of Escherichia coli and C. perfringens from the same potable water sample. In itself, it could be used to assess the public health risk posed by drinking water potentially contaminated with pathogens more resistant to disinfection. PMID:24077714

Maheux, Andree F.; Berube, Eve; Boudreau, Dominique K.; Villeger, Romain; Cantin, Philippe; Boissinot, Maurice; Bissonnette, Luc

2013-01-01

147

Effects of diet and antimicrobials on growth, feed efficiency, intestinal Clostridium perfringens, and ileal weight of broiler chicks.  

PubMed

Five experiments were conducted to evaluate the effects of diet and antimicrobials on weight gain, feed efficiency, ileal weight, and Clostridium perfringens in the ileum of broiler chicks. In the first experiment, glucose, sucrose, and fructose were added to a semipurified diet and the results were compared with those from a practical corn and soybean meal diet. All of the diets were fed with and without bacitracin at a level of 55 ppm. Fructose resulted in the greatest depression in weight gain, followed by sucrose. Bacitracin significantly improved weight gain and feed efficiency of chicks fed the fructose, sucrose, and practical diets. Highly significant inverse correlations were obtained between ileal weight and weight gain and the number of C. perfringens in the ileum and weight gain. In other experiments bacitracin, penicillin, chlortetracycline, oxytetracycline, erythromycin, tylosin, virginiamycin, lincomycin, bambermycins, and carbadox, all at a level of 55 ppm, improved weight gain and feed efficiency and significantly reduced the weight of the ileum and the number of C. perfringens in the ileum of chicks fed the practical diet. The antibacterial agents 3-nitro-4-hydroxy-phenylarsonic acid, arsanilic acid, furazolidone, and sulfathiazole had little to no effect on the 4 parameters evaluated. Virginiamycin and lincomycin at 16.5 and 4.4 ppm, respectively, were shown to be effective. In vitro activities of the antimicrobials against C. perfringens did not directly relate to in vivo activities and the effects on growth and feed efficiency. The results of these experiments support the concept of antimicrobials as growth permittants and provide further evidence for C. perfringens as a causative bacteria for growth depression. PMID:6093090

Stutz, M W; Lawton, G C

1984-10-01

148

Control of Clostridium perfringens in cooked ground beef by carvacrol, cinnamaldehyde, thymol, or oregano oil during chilling.  

PubMed

Inhibition of Clostridium perfringens spore germination and outgrowth by carvacrol, cinnamaldehyde, thymol, and oregano oil was evaluated during abusive chilling of cooked ground beef (75% lean) obtained from a local grocery store. Test substances were mixed into thawed ground beef at concentrations of 0.1, 0.5, 1.0, or 2.0% (wt/wt) along with a heat-activated three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.8 log spores per g. Aliquots (5 g) of the ground beef mixtures were vacuum-packaged and then cooked in a water bath, the temperature of which was raised to 60 degrees C in 1 h. The products were cooled from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h, resulting in 3.18, 4.64, 4.76, and 5.04 log CFU/ g increases, respectively, in C. perfringens populations. Incorporation of test compounds (> or = 0.1%) into the beef completely inhibited C. perfringens spore germination and outgrowth (P < or = 0.05) during exponential cooling of the cooked beef in 12 h. Longer chilling times (15, 18, and 21 h) required greater concentrations to inhibit spore germination and outgrowth. Cinnamaldehyde was significantly (P < 0.05) more effective (< 1.0 log CFU/g growth) at a lower concentration (0.5%) at the most abusive chilling rate evaluated (21 h) than the other compounds. Incorporation of lower levels of these test compounds with other antimicrobials used in meat product formulations may reduce the potential risk of C. perfringens germination and outgrowth during abusive cooling regimes. PMID:16865884

Juneja, Vijay K; Thippareddi, H; Friedman, Mendel

2006-07-01

149

Carvacrol, cinnamaldehyde, oregano oil, and thymol inhibit Clostridium perfringens spore germination and outgrowth in ground turkey during chilling.  

PubMed

Inhibition of Clostridium perfringens by plant-derived carvacrol, cinnamaldehyde, thymol, and oregano oil was evaluated during abusive chilling of cooked ground turkey. Test substances were mixed into thawed turkey product at concentrations of 0.1, 0.5, 1.0, or 2.0% (wt/wt) along with a heat-activated three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.2 to 2.8 log CFU spores per g of turkey meat. Aliquots (5 g) of the ground turkey mixtures were vacuum packaged and then cooked in a water bath, where the temperature was raised to 60 degrees C in I h. The products were cooled from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h, resulting in 2.9-, 5.5-, 4.9-, and 4.2-log CFU/g increases, respectively, in C. perfringens populations in samples without antimicrobials. Incorporation of test compounds (0.1 to 0.5%) into the turkey completely inhibited C. perfringens spore germination and outgrowth (P < or = 0.05) during exponential cooling in 12 h. Longer chilling times (15, 18, and 21 h) required greater concentrations (0.5 to 2.0%) to inhibit spore germination and outgrowth. Cinnamaldehyde was significantly (P < 0.05) more effective (<1.0-log CFU/g growth) than the other compounds at a lower concentration (0.5%) at the most abusive chilling rate evaluated (21 h). These findings establish the value of the plant-derived antimicrobials for inhibiting C. perfringens in commercial ground turkey products. PMID:17265885

Juneja, Vijay K; Friedman, Mendel

2007-01-01

150

The CcpA protein is necessary for efficient sporulation and enterotoxin gene (cpe) regulation in Clostridium perfringens.  

PubMed

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 beta-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). PMID:15292123

Varga, John; Stirewalt, Veronica L; Melville, Stephen B

2004-08-01

151

Clostridium perfringens alpha-toxin activates the sphingomyelin metabolism system in sheep erythrocytes.  

PubMed

Clostridium perfringens alpha-toxin induces hemolysis of rabbit erythrocytes through the activation of glycerophospholipid metabolism. Sheep erythrocytes contain large amounts of sphingomyelin (SM) but not phosphatidylcholine. We investigated the relationship between the toxin-induced hemolysis and SM metabolic system in sheep erythrocytes. Alpha-toxin simultaneously induced hemolysis and a reduction in the levels of SM and formation of ceramide and sphingosine 1-phosphate (S1P). N-Oleoylethanolamine, a ceramidase inhibitor, inhibited the toxin-induced hemolysis and caused ceramide to accumulate in the toxin-treated cells. Furthermore, dl-threo-dihydrosphingosine and B-5354c, isolated from a novel marine bacterium, both sphingosine kinase inhibitors, blocked the toxin-induced hemolysis and production of S1P and caused sphingosine to accumulate. These observations suggest that the toxin-induced activation of the SM metabolic system is closely related to hemolysis. S1P potentiated the toxin-induced hemolysis of saponin-permeabilized erythrocytes but had no effect on that of intact cells. Preincubation of lysated sheep erythrocytes with pertussis toxin blocked the alpha-toxin-induced formation of ceramide from SM. In addition, incubation of C. botulinum C3 exoenzyme-treated lysates of sheep erythrocytes with alpha-toxin caused an accumulation of sphingosine and inhibition of the formation of S1P. These observations suggest that the alpha-toxin-induced hemolysis of sheep erythrocytes is dependent on the activation of the SM metabolic system through GTP-binding proteins, especially the formation of S1P. PMID:14702348

Ochi, Sadayuki; Oda, Masataka; Matsuda, Hisaaki; Ikari, Syusuke; Sakurai, Jun

2004-03-26

152

Tetanus toxin and Clostridium perfringens enterotoxin as tools for the study of exocytosis.  

PubMed

The role of calmodulin in exocytotic secretion was studied using digitonin-permeabilized bovine adrenal chromaffin cells to examine the effect of calmodulin directly introduced into the cells and using tetanus toxin as a specific inhibitor of exocytotic secretion. Addition of calmodulin to the permeabilized cells increased Ca(2+)-dependent norepinephrine release in a dose-dependent manner. The enhancement of release by calmodulin was specific to calmodulin: bovine serum albumin, actin, and caldesmon had no such effect. Enhancement of release by calmodulin occurred at Ca2+ concentrations of more than 10(-6) M and increased with an increase of Mg2+ concentration. The release of norepinephrine enhanced by calmodulin was inhibited by tetanus toxin. These results indicate directly that calmodulin plays an important role in exocytotic secretion from chromaffin cells. Exocytosis is known to occur by fusion of plasma membrane with limiting membranes of secretory vesicles following an increase in intracellular Ca2+. We used the enterotoxin of Clostridium perfringens type A as a specific tool to modify plasma membrane permeability to induce calcium influx. Multigranular exocytosis was recognized electron-microscopically in addition to the single-granular exocytosis in rat anterior pituitary cells and pancreatic acinar cells treated with the enterotoxin in the presence of extracellular Ca2+. The treatment with the enterotoxin did not induce any drastic change in the fine membrane structures of both types of cells. The enterotoxin-treated anterior pituitary cells and pancreatic acinar cells should provide a useful system for studying the molecular mechanism of fusion of membranes in exocytosis. PMID:8154765

Matsuda, M; Okabe, T; Sugimoto, N; Senda, T; Fujita, H

1994-03-01

153

Binding and Internalization of Clostridium perfringens Iota-Toxin in Lipid Rafts  

PubMed Central

Clostridium perfringens iota-toxin is a binary toxin composed of an enzymatic component (Ia) and a binding component (Ib). The oligomer of Ib formed in membranes induces endocytosis. We examined the binding and internalization of Ib by using Cy3-labeled Ib. Labeled Ib was retained at the membranes of MDCK cells for 60 min of incubation at 37°C, and later it was detected in cytoplasmic vesicles. To determine whether Ib associates with lipid rafts, we incubated MDCK cells with Ib at 4 or 37°C and fractionated the Triton-insoluble membranes. An Ib complex of 500 kDa was localized at 37°C to the insoluble fractions that fulfilled the criteria of lipid rafts, but it did not form at 4°C. The amount of complex in the raft fraction reached a maximum after 60 min of incubation at 37°C. When the cells that were preincubated with Ib at 4°C were incubated at 37°C, the complex was detected in the raft fraction. The treatment of MDCK cells with methyl-?-cyclodextrin reduced the localization of the Ib complex to the rafts and the rounding of the cells induced by Ia plus Ib. When 125I-labeled Ia was incubated with the cells in the presence of Ib at 37°C, it was localized in the raft fraction. Surface plasmon resonance analysis revealed that Ia binds to the oligomer of Ib. We conclude that Ib binds to a receptor in membranes and then moves to rafts and that Ia bound to the oligomer of Ib formed in the rafts is internalized. PMID:15155629

Nagahama, Masahiro; Yamaguchi, Akiwo; Hagiyama, Tohko; Ohkubo, Noriko; Kobayashi, Keiko; Sakurai, Jun

2004-01-01

154

Acid phosphatase test proves superior to standard phenotypic identification procedure for Clostridium perfringens strains isolated from water  

PubMed Central

Clostridium perfringens is used as an indicator for persistent faecal pollution as well as to monitor the efficacy of water treatment processes. For these purposes, differentiation between C. perfringens and other Clostridia is essential and is routinely carried out by phenotypic standard tests as proposed in the ISO/CD 6461-2:2002 (ISO_LGMN: lactose fermentation, gelatine liquidation, motility and nitrate reduction). Because the ISO_LGMN procedure is time consuming and labour intensive, the acid phosphatase test was investigated as a possible and much more rapid alternative method for confirmation. The aim of our study was to evaluate and compare confirmation results obtained by these two phenotypic methods using genotypically identified strains, what to our knowledge has not been accomplished before. For this purpose, a species specific PCR method was selected based on the results received for type strains and genotypically characterised environmental strains. For the comparative investigation type strains as well as presumptive C. perfringens isolates from water and faeces samples were used. The acid phosphatase test revealed higher percentage (92%) of correctly identified environmental strains (n = 127) than the ISO_LGMN procedure (83%) and proved to be a sensitive and reliable confirmation method. PMID:21872622

Ryzinska-Paier, G.; Sommer, R.; Haider, J.M.; Knetsch, S.; Frick, C.; Kirschner, A.K.T.; Farnleitner, A.H.

2011-01-01

155

The synergistic necrohemorrhagic action of Clostridium perfringens perfringolysin and alpha toxin in the bovine intestine and against bovine endothelial cells  

PubMed Central

Bovine necrohemorrhagic enteritis is a major cause of mortality in veal calves. Clostridium perfringens is considered as the causative agent, but there has been controversy on the toxins responsible for the disease. Recently, it has been demonstrated that a variety of C. perfringens type A strains can induce necrohemorrhagic lesions in a calf intestinal loop assay. These results put forward alpha toxin and perfringolysin as potential causative toxins, since both are produced by all C. perfringens type A strains. The importance of perfringolysin in the pathogenesis of bovine necrohemorrhagic enteritis has not been studied before. Therefore, the objective of the current study was to evaluate the role of perfringolysin in the development of necrohemorrhagic enteritis lesions in calves and its synergism with alpha toxin. A perfringolysin-deficient mutant, an alpha toxin-deficient mutant and a perfringolysin alpha toxin double mutant were less able to induce necrosis in a calf intestinal loop assay as compared to the wild-type strain. Only complementation with both toxins could restore the activity to that of the wild-type. In addition, perfringolysin and alpha toxin had a synergistic cytotoxic effect on bovine endothelial cells. This endothelial cell damage potentially explains why capillary hemorrhages are an initial step in the development of bovine necrohemorrhagic enteritis. Taken together, our results show that perfringolysin acts synergistically with alpha toxin in the development of necrohemorrhagic enteritis in a calf intestinal loop model and we hypothesize that both toxins act by targeting the endothelial cells. PMID:23782465

2013-01-01

156

Portrait of an Enzyme, a Complete Structural Analysis of a Multimodular beta-N-Acetylglucosaminidase from Clostridium perfringens  

SciTech Connect

Common features of the extracellular carbohydrate-active virulence factors involved in host-pathogen interactions are their large sizes and modular complexities. This has made them recalcitrant to structural analysis, and therefore our understanding of the significance of modularity in these important proteins is lagging. Clostridium perfringens is a prevalent human pathogen that harbors a wide array of large, extracellular carbohydrate-active enzymes and is an excellent and relevant model system to approach this problem. Here we describe the complete structure of C. perfringens GH84C (NagJ), a 1001-amino acid multimodular homolog of the C. perfringens ?-toxin, which was determined using a combination of small angle x-ray scattering and x-ray crystallography. The resulting structure reveals unprecedented insight into how catalysis, carbohydrate-specific adherence, and the formation of molecular complexes with other enzymes via an ultra-tight protein-protein interaction are spatially coordinated in an enzyme involved in a host-pathogen interaction.

Ficko-Blean, E.; Gregg, K; Adams, J; Hehemann, J; Czjzek, M; Smith, S; Boraston, A

2009-01-01

157

Clostridium perfringens septicemia in a long-beaked common dolphin Delphinus capensis: an etiology of gas bubble accumulation in cetaceans.  

PubMed

An adult female long-beaked common dolphin Delphinus capensis live-stranded in La Jolla, California, USA, on July 30, 2012 and subsequently died on the beach. Computed tomography and magnetic resonance imaging revealed gas bubble accumulation in the vasculature, organ parenchyma, mandibular fat pads, and subdermal sheath as well as a gas-filled cavity within the liver, mild caudal abdominal effusion, and fluid in the uterus. Gross examination confirmed these findings and also identified mild ulcerations on the palate, ventral skin, and flukes, uterine necrosis, and multifocal parenchymal cavitations in the brain. Histological review demonstrated necrosis and round clear spaces interpreted as gas bubbles with associated bacterial rods within the brain, liver, spleen, and lymph nodes. Anaerobic cultures of the lung, spleen, liver, bone marrow, and abdominal fluid yielded Clostridium perfringens, which was further identified as type A via a multiplex PCR assay. The gas composition of sampled bubbles was typical of putrefaction gases, which is consistent with the by-products of C. perfringens, a gas-producing bacterium. Gas bubble formation in marine mammals due to barotrauma, and peri- or postmortem off-gassing of supersaturated tissues and blood has been previously described. This case study concluded that a systemic infection of C. perfringens likely resulted in production of gas and toxins, causing tissue necrosis. PMID:25320031

Danil, Kerri; St Leger, Judy A; Dennison, Sophie; Bernaldo de Quirós, Yara; Scadeng, Miriam; Nilson, Erika; Beaulieu, Nicole

2014-10-16

158

Portrait of an Enzyme, a Complete Structural Analysis of a Multimodular ?-N-Acetylglucosaminidase from Clostridium perfringens*S?  

PubMed Central

Common features of the extracellular carbohydrate-active virulence factors involved in host-pathogen interactions are their large sizes and modular complexities. This has made them recalcitrant to structural analysis, and therefore our understanding of the significance of modularity in these important proteins is lagging. Clostridium perfringens is a prevalent human pathogen that harbors a wide array of large, extracellular carbohydrate-active enzymes and is an excellent and relevant model system to approach this problem. Here we describe the complete structure of C. perfringens GH84C (NagJ), a 1001-amino acid multimodular homolog of the C. perfringens ?-toxin, which was determined using a combination of small angle x-ray scattering and x-ray crystallography. The resulting structure reveals unprecedented insight into how catalysis, carbohydrate-specific adherence, and the formation of molecular complexes with other enzymes via an ultra-tight protein-protein interaction are spatially coordinated in an enzyme involved in a host-pathogen interaction. PMID:19193644

Ficko-Blean, Elizabeth; Gregg, Katie J.; Adams, Jarrett J.; Hehemann, Jan-Hendrik; Czjzek, Mirjam; Smith, Steven P.; Boraston, Alisdair B.

2009-01-01

159

Gene expression profiling within the spleen of Clostridium perfringens-challenged Broilers fed antibiotic-medicated and non-medicated diets  

Microsoft Academic Search

BACKGROUND: Clostridium perfringens (Cp) is a Gram-positive anaerobic bacterium that causes necrotic enteritis (NE) in poultry when it overgrows in the small intestine. NE disease has previously been controlled through the use of growth-promoting antibiotics. This practice was recently banned in European countries, leading to significantly increased incidence of NE threatening the poultry industry. Control strategies and technology as substitutes

Aimie J Sarson; Ying Wang; Zhumei Kang; Scot E Dowd; Yang Lu; Hai Yu; Yanming Han; Huaijun Zhou; Joshua Gong

2009-01-01

160

The Effect of Two Different Blends of Essential Oil Components on the Proliferation of Clostridium perfringens in the Intestines of Broiler Chickens  

Microsoft Academic Search

The effect of 2 different blends of essential oils on Clostridium perfringens (Cp) in the intestine and feces of broiler chickens was tested in 6 field trials for each blend. One hundred parts per million of the blends were mixed in a commercial corn-based diet throughout the entire growing period for experimental flocks. Sam- ples from the jejunum, cecum, cloaca,

P. Mitsch; K. Zitterl-Eglseer; B. Kohler; C. Gabler; R. Losa; I. Zimpernik

161

The Murein Hydrolase of the Bacteriophage ?3626 Dual Lysis System Is Active against All Tested Clostridium perfringens Strains  

PubMed Central

Clostridium perfringens commonly occurs in food and feed, can produce an enterotoxin frequently implicated in food-borne disease, and has a substantial negative impact on the poultry industry. As a step towards new approaches for control of this organism, we investigated the cell wall lysis system of C. perfringens bacteriophage ?3626, whose dual lysis gene cassette consists of a holin gene and an endolysin gene. Hol3626 has two membrane-spanning domains (MSDs) and is a group II holin. A positively charged beta turn between the two MSDs suggests that both the amino terminus and the carboxy terminus of Hol3626 might be located outside the cell membrane, a very unusual holin topology. Holin function was experimentally demonstrated by using the ability of the holin to complement a deletion of the heterologous phage ? S holin in ??Sthf. The endolysin gene ply3626 was cloned in Escherichia coli. However, protein synthesis occurred only when bacteria were supplemented with rare tRNAArg and tRNAIle genes. Formation of inclusion bodies could be avoided by drastically lowering the expression level. Amino-terminal modification by a six-histidine tag did not affect enzyme activity and enabled purification by metal chelate affinity chromatography. Ply3626 has an N-terminal amidase domain and a unique C-terminal portion, which might be responsible for the specific lytic range of the enzyme. All 48 tested strains of C. perfringens were sensitive to the murein hydrolase, whereas other clostridia and bacteria belonging to other genera were generally not affected. This highly specific activity towards C. perfringens might be useful for novel biocontrol measures in food, feed, and complex microbial communities. PMID:12406719

Zimmer, Markus; Vukov, Natasa; Scherer, Siegfried; Loessner, Martin J.

2002-01-01

162

A Sporulation Factor Is Involved in the Morphological Change of Clostridium perfringens Biofilms in Response to Temperature  

PubMed Central

Biofilm formation has been associated with bacterial pathogenesis, such as nosocomial and chronic infections, as the resistance of biofilms to environmental stresses has increased. Clostridium perfringens is a Gram-positive spore-forming anaerobic pathogen. This organism survives antibiotic treatment through the formation of biofilms or spores, but the environmental and regulatory factors involved in the biofilm formation remain unclear. Here, we observed that temperature regulates C. perfringens biofilm morphology. At 37°C, C. perfringens adhered to the substrate surface and formed a flat, thin biofilm, herein referred to as adhered biofilm. However, at 25°C, this bacterium did not adhere and produced a threadlike extracellular matrix, forming a viscous, thick biofilm, herein referred to as pellicle biofilm. Pellicle biofilm formation requires the sporulation master regulator, Spo0A, and the toxin regulator, CtrAB, and is enhanced in the absence of the global repressor, AbrB. These transcriptional regulator genes are regulated by each other and temperature. Adhered-biofilm formation requires AbrB and pilA2, which encodes a component of type IV pili (TFP). TFP expression was activated at 37°C and regulated through Spo0A, AbrB, and CtrAB. These results indicate that the morphology of C. perfringens biofilm is dependent on temperature through the differential production of extracellular matrix and the activity of TFP. Moreover, pellicle biofilm formation is involved in sporulation and toxin production. Here, we demonstrated that clostridial biofilm formation is closely associated with sporulation and that the morphological change of the biofilms could play an important role in the pathogenesis of this organism. PMID:24509316

Obana, Nozomu; Nakamura, Kouji

2014-01-01

163

Combination chemotherapy with Clostridium perfringens phospholipase C and cytosine antimetabolites: complementary inhibition directed at membrane lipids.  

PubMed

Tumor cell membranes were susceptible to the action of Clostridium perfringens phospholipase C, and this was reflected by inhibition of cellular replication in culture. The differential susceptibility of two neoplastic cell lines to this enzyme was studied in detail. The growth of sarcoma 180 cells cultured in Fischer's medium was markedly inhibited by phospholipase C; whereas, in contrast, cultured L1210 leukemia cells were relatively resistant to the cytotoxic effects of this enzyme. The differential sensitivity of these two neoplastic cell lines to phospholipase C was corroborated by dye-exclusion tests. Thus, leukemia L1210 cells exposed to a concentration of 0.2 mg of phospholipase C per ml of Fischer's medium for 30 min at 37 degrees C were able to exclude Trypan Blue; whereas, only about 21% of sarcoma 180 cells treated under identical conditions were able to exclude the dye. That the cytotoxicity of phospholipase C to sarcoma 180 was the result of hydrolysis of phospholipids of the plasma membrane was supported by measurements of the rate of hydrolysis of radioactivity from the phospholipid of neoplastic cells prelabeled with [3H]choline. Eighty-two percent of incorporated radioactive choline was released from sarcoma 180 cells treated with phospholipase C in Fischer's medium, whereas, only 20% of the label from [3H]choline was solubilized from L1210 leukemia cells treated with the enzyme under similar conditions. Scanning electron microscopy revealed significant damage to sarcoma 180 cells exposed to phospholipase C in Fischer's medium, which was characterized by alterations in size and shape of cells, disappearance of microvilli, and appearance of fistulas in cell membranes; relatively resistant L1210 leukemic cells did not appear to be markedly damaged by comparable enzyme treatment. Exposure of leukemia L1210 cells to phospholipase C in Puck's saline A increased the sensitivity of these cells to enzymatic action. Under these conditions, a comparable amount of phospholipid was hydrolyzed from surface membranes of sarcoma 180 and leukemia L1210 cells, and the degree of membrane damage appeared to be similar, as measured by the capacity of the tumor cell lines to exclude Trypan Blue and by scanning electron microscopy. The extensive damage to membranes by hydrolysis of phospholipids was not accompanied by a change in the degree of specific binding of [3H]concanavalin A(ConA).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6085755

Lee, M H; Sartorelli, A C

1983-01-01

164

Xylanase supplementation to a wheat-based diet alleviated the intestinal mucosal barrier impairment of broiler chickens challenged by Clostridium perfringens.  

PubMed

The present study was carried out to evaluate the protective effects of xylanase on the intestinal mucosal barrier in broiler chickens challenged with Clostridium perfringens in a 21-day experiment. A total of 336 1-day-old male broiler chicks (Ross 308) were assigned to four treatment groups. A 2×2 factorial arrangement of treatments was used in a randomized complete block design to study the effects of enzyme addition (with or without xylanase 5500 U/kg wheat-based diet), pathogen challenge (with or without C. perfringens challenge), and their interactions. Most C. perfringens-challenged birds had a congested mucosa and focal haemorrhagic lesions in the jejunum. Xylanase addition tended to reduce (P=0.09) the intestinal lesion score in the challenged birds. C. perfringens challenge resulted in decreased villus height/crypt depth ratio in the jejunum and ileum (P<0.05). Xylanase supplementation significantly increased this ratio in the jejunum (P<0.05) and also had the tendency to decrease crypt depth (P=0.065) and increase this ratio in the ileum (P=0.087). Xylanase addition significantly decreased the plasma endotoxin levels of the birds challenged with C. perfringens (P<0.05). Occludin mRNA expression in the jejunum and ileum was significantly decreased by C. perfringens challenge (P<0.05), but xylanase addition significantly increased its expression in the ileum. Xylanase supplementation also significantly increased MUC2 mRNA expression in the ileum (P<0.05). C. perfringens challenge resulted in a significant increase in apoptotic index in all three intestinal segments (P<0.05), but xylanase supplementation obviously decreased apoptotic index in the ileum (P<0.05). In conclusion, xylanase supplementation could alleviate the impairment of intestinal mucosal barrier induced by C. perfringens challenge. PMID:22702457

Liu, Dan; Guo, Shuangshuang; Guo, Yuming

2012-01-01

165

What problems does the food industry have with the spore-forming pathogens Bacillus cereus and Clostridium perfringens?  

PubMed

Spore-forming bacteria are special problems for the food industry. It is not always possible to apply enough heat during food processing to kill spores, thus we have to take advantage of knowledge of the spore-formers to control them. For the meat industry Clostridium perfringens might become a special problem, although this bacterium mainly causes food poisoning through food served in restaurants, hospitals or homes for elderly people (Cliver, 1987; Reynolds, 1987; Gondrosen et al., 1990). The reason for the food poisoning is always the same: meat-containing dishes stored after cooking with insufficient cooling and reheating (Granum, 1990). Even though it should be relatively easy to control this kind of food poisoning, C. perfringens is still one of the most common sources of foodborne diseases. Proper disinfection is necessary to control this type of food poisoning, as it is now clear that only kitchen strains of C. perfringens are able to produce the large amounts of enterotoxin necessary to cause food poisoning (Granum, 1990; Cornillot et al., 1995). Bacillus cereus is more difficult to control, specifically in the dairy industry, where it is now causing the main problems. Insufficient heating of rice-containing dishes has been known to cause B. cereus food poisoning of the emetic kind for a long time (Kramer and Gilbert, 1989), but will not be dealt with in this paper. There are several reasons for the problems in the dairy industry. First of all it seems to be impossible to completely avoid the presence of B. cereus in all milk samples. Secondly the spores are very hydrophobic (Husmark, 1993), and will attach to the surfaces of the pipelines of the dairy industry, where they might multiply and resporulate. A third problem is that pasteurisation heating is insufficient to kill the spores, while competition from other vegetative bacteria is eliminated. It seems that several B. cereus strains have become psychrotrophic over the years, making possible growth at temperatures as low as 4-6 degrees C (Granum et al., 1993a). None of the methods used to control hygiene in the dairy industry so far are able to control B. cereus. This is a continuously increasing problem for the industry but, with emerging knowledge, we should be able to control it. In this paper we will discuss the problems the food industry is facing with C. perfringens and B. cereus, and how these problems might be solved. We will also give our view on how research might ease these problems in the future. PMID:8750663

Andersson, A; Ronner, U; Granum, P E

1995-12-01

166

Enhancing Chicken Mucosal IgA Response Against Clostridium Perfringens a-toxin  

E-print Network

localized lesions upon challenge with C. perfringens type A. These results demonstrate the usefulness of CpaCD as an immunogen for vaccine development against NE for chickens. Chicken CD40 (chCD40) is mainly expressed on the surface of chicken antigen...

Chen, Chang-Hsin 1977-

2012-07-27

167

The First Strain of Clostridium perfringens Isolated from an Avian Source Has an Alpha-Toxin with Divergent Structural and Kinetic Properties † , ‡  

Microsoft Academic Search

Clostridium perfringensalpha-toxin is a 370-residue, zinc-dependent, phospholipase C that is the key virulence determinant in gas gangrene. It is also implicated in the pathogenesis of sudden death syndrome in young animals and necrotic enteritis in chickens. Previously characterized alpha-toxins from different strains of C. perfringens are almost identical in sequence and biochemical properties. We describe the cloning, nucleotide sequencing, expression,

Neil Justin; Nicola Walker; Helen L. Bullifent; Glenn Songer; Dawn M. Bueschel; Helen Jost; Claire Naylor; Julie Miller; David S. Moss; Richard W. Titball; Ajit K. Basak

2002-01-01

168

The VirR Response Regulator from Clostridium perfringens Binds Independently to Two Imperfect Direct Repeats Located Upstream of the pfoA Promoter  

Microsoft Academic Search

Regulation of toxin production in the gram-positive anaerobe Clostridium perfringens occurs at the level of transcription and involves a two-component signal transduction system. The sensor histidine kinase is encoded by the virS gene, while its cognate response regulator is encoded by the virR gene. We have constructed a VirR expression plasmid in Escherichia coli and purified the resultant His-tagged VirR

JACKIE K. CHEUNG; JULIAN I. ROOD

2000-01-01

169

The Spatial Organization of the VirR Boxes Is Critical for VirR-Mediated Expression of the Perfringolysin O Gene, pfoA, from Clostridium perfringens  

Microsoft Academic Search

The transcriptional regulation of toxin production in the gram-positive anaerobe Clostridium perfringens involves a two-component signal transduction system that comprises the VirS sensor histidine kinase and its cognate response regulator, VirR. Previous studies showed that VirR binds independently to a pair of imperfect direct repeats, now designated VirR box 1 and VirR box 2, located immediately upstream of the promoter

Jackie K. Cheung; Bruno Dupuy; Deanna S. Deveson; Julian I. Rood

2004-01-01

170

Effect of meat ingredients (sodium nitrite and erythorbate) and processing (vacuum storage and packaging atmosphere) on germination and outgrowth of Clostridium perfringens spores in ham during abusive cooling.  

PubMed

The effect of nitrite and erythorbate on Clostridium perfringens spore germination and outgrowth in ham during abusive cooling (15 h) was evaluated. Ham was formulated with ground pork, NaNO2 (0, 50, 100, 150 or 200 ppm) and sodium erythorbate (0 or 547 ppm). Ten grams of meat (stored at 5 °C for 3 or 24 h after preparation) were transferred to a vacuum bag and inoculated with a three-strain C. perfringens spore cocktail to obtain an inoculum of ca. 2.5 log spores/g. The bags were vacuum-sealed, and the meat was heat treated (75 °C, 20 min) and cooled within 15 h from 54.4 to 7.2 °C. Residual nitrite was determined before and after heat treatment using ion chromatography with colorimetric detection. Cooling of ham (control) stored for 3 and 24 h, resulted in C. perfringens population increases of 1.46 and 4.20 log CFU/g, respectively. For samples that contained low NaNO2 concentrations and were stored for 3 h, C. perfringens populations of 5.22 and 2.83 log CFU/g were observed with or without sodium erythorbate, respectively. Residual nitrite was stable (p > 0.05) for both storage times. Meat processing ingredients (sodium nitrite and sodium erythorbate) and their concentrations, and storage time subsequent to preparation of meat (oxygen content) affect C. perfringens spore germination and outgrowth during abusive cooling of ham. PMID:23664261

Redondo-Solano, Mauricio; Valenzuela-Martinez, Carol; Cassada, David A; Snow, Daniel D; Juneja, Vijay K; Burson, Dennis E; Thippareddi, Harshavardhan

2013-09-01

171

The NanI and NanJ Sialidases of Clostridium perfringens Are Not Essential for Virulence?  

PubMed Central

The essential toxin in Clostridium perfringens-mediated gas gangrene or clostridial myonecrosis is alpha-toxin, although other toxins and extracellular enzymes may also be involved. In many bacterial pathogens extracellular sialidases are important virulence factors, and it has been suggested that sialidases may play a role in gas gangrene. C. perfringens strains have combinations of three different sialidase genes, two of which, nanI and nanJ, encode secreted sialidases. The nanI and nanJ genes were insertionally inactivated by homologous recombination in derivatives of sequenced strain 13 and were shown to encode two functional secreted sialidases, NanI and NanJ. Analysis of these derivatives showed that NanI was the major sialidase in this organism. Mutation of nanI resulted in loss of most of the secreted sialidase activity, and the residual activity was eliminated by subsequent mutation of the nanJ gene. Only a slight reduction in the total sialidase activity was observed in a nanJ mutant. Cytotoxicity assays using the B16 melanoma cell line showed that supernatants containing NanI or overexpressing NanJ enhanced alpha-toxin-mediated cytotoxicity. Finally, the ability of nanI, nanJ, and nanIJ mutants to cause disease was assessed in a mouse myonecrosis model. No attenuation of virulence was observed for any of these strains, providing evidence that neither the NanI sialidase nor the NanJ sialidase is essential for virulence. PMID:19651873

Chiarezza, Martina; Lyras, Dena; Pidot, Sacha J.; Flores-Diaz, Marietta; Awad, Milena M.; Kennedy, Catherine L.; Cordner, Leanne M.; Phumoonna, Tongted; Poon, Rachael; Hughes, Meredith L.; Emmins, John J.; Alape-Giron, Alberto; Rood, Julian I.

2009-01-01

172

Haemorhagic enterotoxemia by Clostridium perfringens type C and type A in silver foxes.  

PubMed

Type C and type A of C. perfringens were detected in the seat of natural infections in silver foxes characterized by symptoms of haemorrhagic enterotoxemia. In all of the dead foxes characteristic changes were noted in the small intestine and parenchymatous organs. The production of alpha and beta toxins by isolated bacteria was confirmed by the bioassay using white mice and by PCR. The results of the drug sensitivity testing showed that isolated strains were highly susceptible to amoxicillin with clavulanic acid, metronidazole, doxycycline and penicillin with streptomycin. PMID:24724490

Jarosz, ? S; Gradzki, Z; Smiech, A; Kalinowski, M

2014-01-01

173

Expression of a Clostridium perfringens genome-encoded putative N-acetylmuramoyl-L-alanine amidase as a potential antimicrobial to control the bacterium.  

PubMed

Clostridium perfringens is a gram-positive, spore-forming anaerobic bacterium that plays a substantial role in non-foodborne human, animal, and avian diseases as well as human foodborne disease. Previously discovered C. perfringens bacteriophage lytic enzyme amino acid sequences were utilized to identify putative prophage lysins or autolysins by BLAST analyses encoded by the genomes of C. perfringens isolates. A predicted N-acetylmuramoyl-L-alanine amidase or MurNAc-LAA (also known as peptidoglycan aminohydrolase, NAMLA amidase, NAMLAA, amidase 3, and peptidoglycan amidase; EC 3.5.1.28) was identified that would hydrolyze the amide bond between N-acetylmuramoyl and L-amino acids in certain cell wall glycopeptides. The gene encoding this protein was subsequently cloned from genomic DNA of a C. perfringens isolate by polymerase chain reaction, and the gene product (PlyCpAmi) was expressed to determine if it could be utilized as an antimicrobial to control the bacterium. By spot assay, lytic zones were observed for the purified amidase and the E. coli expression host cellular lysate containing the amidase gene. Turbidity reduction and plate counts of C. perfringens cultures were significantly reduced by the expressed protein and observed morphologies for cells treated with the amidase appeared vacuolated, non-intact, and injured compared to the untreated cells. Among a variety of C. perfringens strains, there was little gene sequence heterogeneity that varied from 1 to 21 nucleotide differences. The results further demonstrate that it is possible to discover lytic proteins encoded in the genomes of bacteria that could be utilized to control bacterial pathogens. PMID:23934074

Tillman, Glenn E; Simmons, Mustafa; Garrish, Johnna K; Seal, Bruce S

2013-11-01

174

Clostridium perfringens as the Cause of Death of a Captive Atlantic Bottlenosed Dolphin (Tursiops truncatus)  

Microsoft Academic Search

A previously healthy captive fe- male bottlenosed dolphin (Tursiops truncatus) died suddenly. At necropsy, Clostridium per- f ringens was isolated from dorsal muscle, blood, left heart ventricle, thoracic fluid, and abdom- inal fluid. An identical strain was recovered from pool water. A male dolphin in the same pool had inflicted several \\

John D. Buck; L. Louise Shepard

175

Clostridium perfringens Phospholipase C Induced ROS Production and Cytotoxicity Require PKC, MEK1 and NF?B Activation  

PubMed Central

Clostridium perfringens phospholipase C (CpPLC), also called ?-toxin, is the most toxic extracellular enzyme produced by this bacteria and is essential for virulence in gas gangrene. At lytic concentrations, CpPLC causes membrane disruption, whereas at sublytic concentrations this toxin causes oxidative stress and activates the MEK/ERK pathway, which contributes to its cytotoxic and myotoxic effects. In the present work, the role of PKC, ERK 1/2 and NF?B signalling pathways in ROS generation induced by CpPLC and their contribution to CpPLC-induced cytotoxicity was evaluated. The results demonstrate that CpPLC induces ROS production through PKC, MEK/ERK and NF?B pathways, the latter being activated by the MEK/ERK signalling cascade. Inhibition of either of these signalling pathways prevents CpPLC's cytotoxic effect. In addition, it was demonstrated that NF?B inhibition leads to a significant reduction in the myotoxicity induced by intramuscular injection of CpPLC in mice. Understanding the role of these signalling pathways could lead towards developing rational therapeutic strategies aimed to reduce cell death during a clostridialmyonecrosis. PMID:24466113

Monturiol-Gross, Laura; Flores-Diaz, Marietta; Pineda-Padilla, Maria Jose; Castro-Castro, Ana Cristina; Alape-Giron, Alberto

2014-01-01

176

Clostridium perfringens phospholipase C induced ROS production and cytotoxicity require PKC, MEK1 and NF?B activation.  

PubMed

Clostridium perfringens phospholipase C (CpPLC), also called ?-toxin, is the most toxic extracellular enzyme produced by this bacteria and is essential for virulence in gas gangrene. At lytic concentrations, CpPLC causes membrane disruption, whereas at sublytic concentrations this toxin causes oxidative stress and activates the MEK/ERK pathway, which contributes to its cytotoxic and myotoxic effects. In the present work, the role of PKC, ERK 1/2 and NF?B signalling pathways in ROS generation induced by CpPLC and their contribution to CpPLC-induced cytotoxicity was evaluated. The results demonstrate that CpPLC induces ROS production through PKC, MEK/ERK and NF?B pathways, the latter being activated by the MEK/ERK signalling cascade. Inhibition of either of these signalling pathways prevents CpPLC's cytotoxic effect. In addition, it was demonstrated that NF?B inhibition leads to a significant reduction in the myotoxicity induced by intramuscular injection of CpPLC in mice. Understanding the role of these signalling pathways could lead towards developing rational therapeutic strategies aimed to reduce cell death during a clostridialmyonecrosis. PMID:24466113

Monturiol-Gross, Laura; Flores-Díaz, Marietta; Pineda-Padilla, Maria Jose; Castro-Castro, Ana Cristina; Alape-Giron, Alberto

2014-01-01

177

Crystal structure of the phosphate-binding protein (PBP-1) of an ABC-type phosphate transporter from Clostridium perfringens.  

PubMed

Phosphate limitation is an important environmental stress that affects the metabolism of various organisms and, in particular, can trigger the virulence of numerous bacterial pathogens. Clostridium perfringens, a human pathogen, is one of the most common causes of enteritis necroticans, gas gangrene and food poisoning. Here, we focused on the high affinity phosphate-binding protein (PBP-1) of an ABC-type transporter, responsible for cellular phosphate uptake. We report the crystal structure (1.65 Å resolution) of the protein in complex with phosphate. Interestingly, PBP-1 does not form the short, low-barrier hydrogen bond with phosphate that is typical of previously characterized phosphate-binding proteins, but rather a canonical hydrogen bond. In its unique binding configuration, PBP-1 forms an unusually high number of hydrogen bonds (14) with the phosphate anion. Discrimination experiments reveal that PBP-1 is the least selective PBP characterised so far and is able to discriminate phosphate from its close competing anion, arsenate, by ~150-fold. PMID:25338617

Gonzalez, Daniel; Richez, Magali; Bergonzi, Celine; Chabriere, Eric; Elias, Mikael

2014-01-01

178

The Interaction of a Carbohydrate-Binding Module from a Clostridium perfringens N-Acetyl-beta-hexosaminidase with its Carbohydrate Receptor  

SciTech Connect

Clostridium perfringens is a notable colonizer of the human gastrointestinal tract. This bacterium is quite remarkable for a human pathogen by the number of glycoside hydrolases found in its genome. The modularity of these enzymes is striking as is the frequent occurrence of modules having amino acid sequence identity with family 32 carbohydrate-binding modules (CBMs), often referred to as F5/8 domains. Here we report the properties of family 32 CBMs from a C. perfringens N-acetyl-{beta}-hexosaminidase. Macroarray, UV difference, and isothermal titration calorimetry binding studies indicate a preference for the disaccharide LacNAc ({beta}-d-galactosyl-1,4-{beta}-d-N-acetylglucosamine). The molecular details of the interaction of this CBM with galactose, LacNAc, and the type II blood group H-trisaccharide are revealed by x-ray crystallographic studies at resolutions of 1.49, 2.4, and 2.3 Angstroms, respectively.

Ficko-Blean,E.; Boraston, A.

2006-01-01

179

Phenotypic Characterization of Enterotoxigenic Clostridium perfringens Isolates from Non-foodborne Human Gastrointestinal Diseases  

Microsoft Academic Search

Clostridium perfringensenterotoxin (CPE) has been implicated as an important virulence factor inC. perfringenstype A food poisoning and several non-foodborne human gastrointestinal (GI) illnesses, including antibiotic-associated diarrhea (AAD) and sporadic diarrhea (SPOR). Recent studies have revealed genotypic differences betweencpe-positive isolates originating from different disease sources, with most, or all, food poisoning isolates carrying a chomosomalcpeand most, or all, non-foodborne human GI

Renee E Collie; John F Kokai-Kun; Bruce A McClane

1998-01-01

180

Characterization of bacteriophages virulent for Clostridium perfringens and identification of phage lytic enzymes as alternatives to antibiotics for potential control of the bacterium1  

PubMed Central

There has been a resurgent interest in the use of bacteriophages or their gene products to control bacterial pathogens as alternatives to currently used antibiotics. Clostridium perfringens is a gram-positive, spore-forming anaerobic bacterium that plays a significant role in human foodborne disease as well as nonfoodborne human, animal, and avian diseases. Countries that have complied with the ban on antimicrobial growth promoters in feeds have reported increased incidences of C. perfringens-associated diseases in poultry. To address these issues, new antimicrobial agents, putative lysins encoded by the genomes of bacteriophages, are being identified in our laboratory. Poultry intestinal material, soil, sewage, and poultry processing drainage water were screened for virulent bacteriophages that could lyse C. perfringens and produce clear plaques in spot assays. Bacteriophages were isolated that had long noncontractile tails, members of the family Siphoviridae, and with short noncontractile tails, members of the family Podoviridae. Several bacteriophage genes were identified that encoded N-acetylmuramoyl-l-alanine amidases, lysozyme-endopeptidases, and a zinc carboxypeptidase domain that has not been previously reported in viral genomes. Putative phage lysin genes (ply) were cloned and expressed in Escherichia coli. The recombinant lysins were amidases capable of lysing both parental phage host strains of C. perfringens as well as other strains of the bacterium in spot and turbidity reduction assays, but did not lyse any clostridia beyond the species. Consequently, bacteriophage gene products could eventually be used to target bacterial pathogens, such as C. perfringens via a species-specific strategy, to control animal and human diseases without having deleterious effects on beneficial probiotic bacteria. PMID:23300321

Seal, Bruce S.

2014-01-01

181

Characterization of bacteriophages virulent for Clostridium perfringens and identification of phage lytic enzymes as alternatives to antibiotics for potential control of the bacterium.  

PubMed

There has been a resurgent interest in the use of bacteriophages or their gene products to control bacterial pathogens as alternatives to currently used antibiotics. Clostridium perfringens is a gram-positive, spore-forming anaerobic bacterium that plays a significant role in human foodborne disease as well as non-foodborne human, animal, and avian diseases. Countries that have complied with the ban on antimicrobial growth promoters in feeds have reported increased incidences of C. perfringens-associated diseases in poultry. To address these issues, new antimicrobial agents, putative lysins encoded by the genomes of bacteriophages, are being identified in our laboratory. Poultry intestinal material, soil, sewage, and poultry processing drainage water were screened for virulent bacteriophages that could lyse C. perfringens and produce clear plaques in spot assays. Bacteriophages were isolated that had long noncontractile tails, members of the family Siphoviridae, and with short noncontractile tails, members of the family Podoviridae. Several bacteriophage genes were identified that encoded N-acetylmuramoyl-l-alanine amidases, lysozyme-endopeptidases, and a zinc carboxypeptidase domain that has not been previously reported in viral genomes. Putative phage lysin genes (ply) were cloned and expressed in Escherichia coli. The recombinant lysins were amidases capable of lysing both parental phage host strains of C. perfringens as well as other strains of the bacterium in spot and turbidity reduction assays, but did not lyse any clostridia beyond the species. Consequently, bacteriophage gene products could eventually be used to target bacterial pathogens, such as C. perfringens via a species-specific strategy, to control animal and human diseases without having deleterious effects on beneficial probiotic bacteria. PMID:23300321

Seal, Bruce S

2013-02-01

182

Hemolytic and sphingomyelinase activities of Clostridium perfringens alpha-toxin are dependent on a domain homologous to that of an enzyme from the human arachidonic acid pathway.  

PubMed Central

The N-terminal domain of Clostridium perfringens alpha-toxin, homologous with the nontoxic phospholipase C of Bacillus cereus, was expressed in Escherichia coli and shown to retain all of the phosphatidylcholine hydrolyzing activity of the alpha-toxin, but not the sphingomyelinase, hemolytic, or lethal activities. The C-terminal domain of alpha-toxin showed sequence and predicted structural homologies with the N-terminal region of arachidonate 5-lipoxygenase, an enzyme from the human arachidonic acid pathway which plays a role in inflammatory and cardiovascular diseases in humans. Images PMID:1902199

Titball, R W; Leslie, D L; Harvey, S; Kelly, D

1991-01-01

183

Cytotoxic effects by microinjection of ADP-ribosylated skeletal muscle G-actin in PtK2 cells in the absence of Clostridium perfringens iota toxin  

Microsoft Academic Search

The ADP-ribosylating toxinsClostridium botulinum C2 toxin andC. perfringens iota toxin, which ADP-ribosylate monomeric G-actin at Arg-177 but not the polymeric F-actin, induce depolymerization of the\\u000a actin cytoskeleton in cultured cells. Since ADP-ribosylated G-actin has properties of a barbed-end-capping protein, we studied\\u000a whether the ADP-ribosylated actin affects the actin cytoskeleton of PtK2 cells even in the absence of ADP-ribosylating toxin.\\u000a Skeletal

Gabriele Kiefer; Monika Lerner; Peter Sehr; Ingo Just; Klaus Aktories

1996-01-01

184

Activation of Clostridium perfringens spores under conditions that disrupt hydrophobic interactions of biological macromolecules.  

PubMed Central

The effect of hydrophobic interactions on the activation of C. perfringens NCTC 8679 spores was examined by heating spores under conditions that modify the hydrophobic properties of biological macromolecules. After the activation treatment and a washing procedure, germination was determined by measuring the decrease in optical density of spores suspended in an enriched germination medium. Activation was inhibited for spores that were treated under conditions that strengthen hydrophobic interactions, i.e., a decrease in pH or the presence of structure-stabilizing neutral salts. Activation was enhanced by treatment under conditions that disrupt hydrophobic interactions, i.e., an increase in pH or the presence of urea, dibucaine, or denaturing neutral salts. A deactivation treatment with the antichaotropic salt (NH4)2SO4 reversed activation by the chaotropic salt CaCl2 and to a lesser extent reversed activation by sublethal heat (75 degrees C) or urea. Most treatments that enhanced activation increased spore injury at higher temperatures, which resulted in decreased germination. However, (NH4)2SO4 and a decrease in pH from 5.6 to 3.8, which inhibited activation, also favored injury. The results suggest that activation involves a conformational change of a spore protein(s) through weakening of hydrophobic molecular forces and that activation and injury occur at different spore sites. PMID:2902828

Craven, S E

1988-01-01

185

Impact of cooking, cooling, and subsequent refrigeration on the growth or survival of Clostridium perfringens in cooked meat and poultry products.  

PubMed

In January 1999, the Food Safety and Inspection Service (FSIS) finalized performance standards for the cooking and chilling of meat and poultry products in federally inspected establishments. More restrictive chilling (stabilization) requirements were adopted despite the lack of strong evidence of a public health risk posed by industry practices employing the original May 1988 guidelines (U.S. Department of Agriculture FSIS Directive 7110.3). Baseline data led the FSIS to estimate a "worst case" of 10(4) Clostridium perfringens cells per g in raw meat products. The rationale for the FSIS performance standards was based on this estimate and the assumption that the numbers detected in the baseline study were spores that could survive cooking. The assumptions underlying the regulation stimulated work in our laboratory to help address why there have been so few documented outbreaks of C. perfringens illness associated with the consumption of commercially processed cooked meat and poultry products. Our research took into account the numbers of C. perfringens spores in both raw and cooked products. One hundred ninety-seven raw comminuted meat samples were cooked to 73.9 degrees C and analyzed for C. perfringens levels. All but two samples had undetectable levels (<3 spores per g). Two ground pork samples contained 3.3 and 66 spores per g. Research was also conducted to determine the effect of chilling on the outgrowth of C. perfringens spores in cured and uncured turkey. Raw meat blends inoculated with C. perfringens spores, cooked to 73.9 degrees C, and chilled according to current guidelines or under abuse conditions yielded increases of 2.25 and 2.44 log10 CFU/g for uncured turkey chilled for 6 h and an increase of 3.07 log10 CFU/g for cured turkey chilled for 24 h. No growth occurred in cured turkey during a 6-h cooling period. Furthermore, the fate of C. perfringens in cooked cured and uncured turkey held at refrigeration temperatures was investigated. C. perfringens levels decreased by 2.52, 2.54, and 2.75 log10 CFU/g in cured turkey held at 0.6, 4.4, and 10 degrees C, respectively, for 7 days. Finally, 48 production lots of ready-to-eat meat products that had deviated from FSIS guidelines were analyzed for C. perfringens levels. To date, 456 samples have been tested, and all but 25 (ranging from 100 to 710 CFU/g) of the samples contained C. perfringens at levels of <100 CFU/g. These results further support historical food safety data that suggest a very low public health risk associated with C. perfringens in commercially processed ready-to-eat meat and poultry products. PMID:12870757

Kalinowski, Robin M; Tompkin, R Bruce; Bodnaruk, Peter W; Pruett, W Payton

2003-07-01

186

A Fatal Spontaneous Gas Gangrene due to Clostridium perfringens during Neutropenia of Allogeneic Stem Cell Transplantation: Case Report and Literature Review  

PubMed Central

Most cases of gas gangrene caused by Clostridium species begin with trauma-related injuries but in rare cases, spontaneous gas gangrene (SGG) can occur when patients have conditions such as advanced malignancy, diabetes, or immunosuppression. Clostridium perfringens, a rare cause of SGG, exists as normal flora of skin and intestines of human. Adequate antibiotics with surgical debridement of infected tissue is the only curative therapeutic management. Mortality rate among adults is reported range of 67-100% and majority of deaths are occurred within 24 hours of onset. We experienced a case of SGG on the trunk, buttock and thigh in a neutropenic patient with acute lymphoblastic leukemia. His clinical course was rapid and fatal during pre-engraftment neutropenic period of allogeneic stem cell transplantation. PMID:25298910

Lee, Hae-Lim; Cho, Sung-Yeon; Ko, Yumi; Hyun, Ji In; Kim, Bo Kyoung; Seo, Jae Hyun; Lee, Jung Woo; Lee, Seok

2014-01-01

187

Purification of two Clostridium perfringens enterotoxin-like proteins and their effects on membrane permeability in primary cultures of adult rat hepatocytes.  

PubMed Central

We isolated two proteins, ET-1 and ET-2, from the sporangial extracts of Clostridium perfringens type A. Both proteins had some properties in common with the well-known C. perfringens enterotoxin. ET-1 and ET-2 behaved as single and distinct entities in anion exchange chromatography and disk gel electrophoresis. ET-2 was the more anionic protein since it eluted more slowly from the anion exchange column and migrated faster toward the anode in polyacrylamide disk gel electrophoresis (pH 8.5, native gels). Additionally, in this electrophoretic system ET-2 was not distinguishable from the enterotoxin. The amino acid compositions of ET-1 and ET-2 were similar but differed in a few amino acid residues. The values for both proteins were also similar to the published reports of others for the enterotoxin. Both ET-1 and ET-2 showed lines of identity in agar gel double immunodiffusion against anti-enterotoxin antiserum. Both ET-1 and ET-2 were toxic for rat hepatocytes in primary monolayer culture as determined by accelerated exodus of L-[14C]glucose from preloaded cells and by the rapid uptake of 45Ca2+ after exposure to the proteins. In this regard, ET-1 and ET-2 appeared to be identical in mechanism of action to what has been regarded in the literature as "the" C. perfringens enterotoxin. Interestingly, ET-2 was 3 to 10 times more toxic on a weight basis than ET-1 was. Images PMID:6292107

Dasgupta, B R; Pariza, M W

1982-01-01

188

B-cell epitope of beta toxin of Clostridium perfringens genetically conjugated to a carrier protein: expression, purification and characterization of the chimeric protein.  

PubMed

Beta toxin (btx) is the prime virulence factor for the pathogenesis of Clostridium perfringens type C strain, known to cause necrotic enteritis and enterotoxaemia in mammalian species. The existing vaccines targeting btx are formaldehyde inactivated culture filtrates of Clostridium. These filtrates raise antigenic load in the host leading to nonspecific and poor responses. The present study aimed to overcome these drawbacks and generate a chimeric protein carrying in silico identified B-cell epitope of btx fused with a carrier protein as a vaccine candidate. Using bioinformatic tools, three stretches of amino acids were predicted as putative B-cell epitopes. One of the epitopes spanning 140-156 amino acid residues was genetically conjugated with B-subunit of heat labile enterotoxin (LTB) of Escherichia coli and expressed as a translational fusion in Vibrio cholerae secretory expression system. High level expression of the recombinant fusion protein rLTB-Btx140-156 was obtained and the protein was successfully purified. The recombinant protein retained the native LTB property to pentamerize and bind to GM1 ganglioside receptor of LTB. The antigenicity of both the epitope and the carrier protein was maintained in fusion protein as indicated by immunoblotting against anti-LTB and anti-btx antibody. The rLTB-Btx140-156 fusion protein therefore can be evaluated as a potential vaccine candidate against C. perfringens. PMID:24996028

Bhatia, Bharti; Solanki, Amit Kumar; Kaushik, Himani; Dixit, Aparna; Garg, Lalit C

2014-10-01

189

The effect of feeding a commercial essential oil product on Clostridium perfringens numbers in the intestine of broiler chickens measured by real-time PCR targeting the ?-toxin-encoding gene ( plc)  

Microsoft Academic Search

Proliferation of Clostridium perfringens type A in the broiler intestinal tract is related to poor growth and litter quality, and can under certain conditions lead to the development of necrotic enteritis (NE), a severe gastrointestinal disease in broilers. The aim of the present study was to investigate the influence of a commercial essential oil blend, CRINA® Poultry, on the intestinal

L. Abildgaard; O. Hojberg; A. Schramm; K. M. Balle; R. M. Engberg

2010-01-01

190

The Clostridium perfringens germinant receptor protein GerKC is located in the spore inner membrane and is crucial for spore germination.  

PubMed

The Gram-positive, anaerobic, spore-forming bacterium Clostridium perfringens causes a variety of diseases in both humans and animals, and spore germination is thought to be the first stage of C. perfringens infection. Previous studies have indicated that the germinant receptor (GR) proteins encoded by the bicistronic gerKA-gerKC operon as well as the proteins encoded by the gerKB and gerAA genes are required for normal germination of C. perfringens spores. We now report the individual role of these GR proteins by analyzing the germination of strains carrying mutations in gerKA, gerKC, or both gerKB and gerAA. Western blot analysis was also used to determine the location and numbers of GerKC proteins in spores. Conclusions from this work include the following: (i) gerKC mutant spores germinate extremely poorly with KCl, l-asparagine, a mixture of asparagine and KCl, or NaPi; (ii) gerKC spores germinate significantly more slowly than wild-type and other GR mutant spores with a 1:1 chelate of Ca(2+) and dipicolinic acid and very slightly more slowly with dodecylamine; (iii) the germination defects in gerKC spores are largely restored by expressing the wild-type gerKA-gerKC operon in trans; (iv) GerKC is required for the spores' viability, almost certainly because of the gerKC spores' poor germination; and (v) GerKC is located in the spores' inner membrane, with ?250 molecules/spore. Collectively, these results indicate that GerKC is the main GR protein required for nutrient and nonnutrient germination of spores of C. perfringens food-poisoning isolates. PMID:24013629

Banawas, Saeed; Paredes-Sabja, Daniel; Korza, George; Li, Yunfeng; Hao, Bing; Setlow, Peter; Sarker, Mahfuzur R

2013-11-01

191

The Clostridium perfringens Germinant Receptor Protein GerKC Is Located in the Spore Inner Membrane and Is Crucial for Spore Germination  

PubMed Central

The Gram-positive, anaerobic, spore-forming bacterium Clostridium perfringens causes a variety of diseases in both humans and animals, and spore germination is thought to be the first stage of C. perfringens infection. Previous studies have indicated that the germinant receptor (GR) proteins encoded by the bicistronic gerKA-gerKC operon as well as the proteins encoded by the gerKB and gerAA genes are required for normal germination of C. perfringens spores. We now report the individual role of these GR proteins by analyzing the germination of strains carrying mutations in gerKA, gerKC, or both gerKB and gerAA. Western blot analysis was also used to determine the location and numbers of GerKC proteins in spores. Conclusions from this work include the following: (i) gerKC mutant spores germinate extremely poorly with KCl, l-asparagine, a mixture of asparagine and KCl, or NaPi; (ii) gerKC spores germinate significantly more slowly than wild-type and other GR mutant spores with a 1:1 chelate of Ca2+ and dipicolinic acid and very slightly more slowly with dodecylamine; (iii) the germination defects in gerKC spores are largely restored by expressing the wild-type gerKA-gerKC operon in trans; (iv) GerKC is required for the spores' viability, almost certainly because of the gerKC spores' poor germination; and (v) GerKC is located in the spores' inner membrane, with ?250 molecules/spore. Collectively, these results indicate that GerKC is the main GR protein required for nutrient and nonnutrient germination of spores of C. perfringens food-poisoning isolates. PMID:24013629

Banawas, Saeed; Paredes-Sabja, Daniel; Korza, George; Li, Yunfeng; Hao, Bing; Setlow, Peter

2013-01-01

192

Effects of pH shifts, bile salts, and glucose on sporulation of Clostridium perfringens NCTC 8798.  

PubMed Central

The sporulation of Clostridium perfringens NCTC 8798 was studied after exposing vegetative cells to: pH values of 1.5 to 8.0 in fluid thioglycolate broth (for 2h) and then transferring them to Duncan-Strong (DS) sporulation medium; sodium cholate or sodium deoxycholate (0.3 to 6.5 mM) in DS medium; or Rhia-Solberg medium with 0.4% (wt/wt) starch, glucose, or both added at 0 to 55 mM. At pH 1.5, no culturable heat-resistant spores were formed. For cells exposed to pH 3.0, 4.0, 5.0, or 6.0, increases in heat-resistant spores were not seen until after a lag of 12 to 13 h, whereas the lag was only 2 to 3 h for cells exposed to pH 7.0 or 8.0. Maximal spore crops were produced after only 6 to 8 h for cells exposed to pH 7 or 8, but 16 to 18 h was required for production of maximal spore crops by cells exposed to the lower-pH media. The addition of sodium cholate (3.5 to 6.5 mM) to DS medium only slightly reduced the culturable heat-resistant spore count from 1.9 X 10(7) to 3 X 10(6)/ml. The addition of 1.8 mM or more sodium deoxycholate reduced the culturable heat-resistant spore count to less than 10/ ml. When either starch or glucose alone was added to Rhia-Solberg medium there was no production of culturable heat-resistant spores, but a combination of 0.4% (wt/wt) starch and 4.4 mM glucose yielded 6 X 10(5) spores/ml. The spore production remained at this level for glucose concentrations of 6 to 22 mM, but then declined to about 3 X 10(3) spores per ml at higher concentrations. PMID:6261681

Hickey, C S; Johnson, M G

1981-01-01

193

Clostridium perfringens enterotoxin carboxy-terminal fragment is a novel tumor-homing peptide for human ovarian cancer  

PubMed Central

Background Development of innovative, effective therapies against recurrent/chemotherapy-resistant ovarian cancer remains a high priority. Using high-throughput technologies to analyze genetic fingerprints of ovarian cancer, we have discovered extremely high expression of the genes encoding the proteins claudin-3 and claudin-4. Methods Because claudin-3 and -4 are the epithelial receptors for Clostridium perfringens enterotoxin (CPE), and are sufficient to mediate CPE binding, in this study we evaluated the in vitro and in vivo bioactivity of the carboxy-terminal fragment of CPE (i.e., CPE290-319 binding peptide) as a carrier for tumor imaging agents and intracellular delivery of therapeutic drugs. Claudin-3 and -4 expression was examined with rt-PCR and flow cytometry in multiple primary ovarian carcinoma cell lines. Cell binding assays were used to assess the accuracy and specificity of the CPE peptide in vitro against primary chemotherapy-resistant ovarian carcinoma cell lines. Confocal microscopy and biodistribution assays were performed to evaluate the localization and uptake of the FITC-conjugated CPE peptide in established tumor tissue. Results Using a FITC-conjugated CPE peptide we show specific in vitro and in vivo binding to multiple primary chemotherapy resistant ovarian cancer cell lines. Bio-distribution studies in SCID mice harboring clinically relevant animal models of chemotherapy resistant ovarian carcinoma showed higher uptake of the peptide in tumor cells than in normal organs. Imunofluorescence was detectable within discrete accumulations (i.e., tumor spheroids) or even single chemotherapy resistant ovarian cancer cells floating in the ascites of xenografted animals while a time-dependent internalization of the FITC-conjugated CPE peptide was consistently noted in chemotherapy-resistant ovarian tumor cells by confocal microscopy. Conclusions Based on the high levels of claudin-3 and -4 expression in chemotherapy-resistant ovarian cancer and other highly aggressive human epithelial tumors including breast, prostate and pancreatic cancers, CPE peptide holds promise as a lead peptide for the development of new diagnostic tracers or alternative anticancer agents. PMID:20598131

2010-01-01

194

Effects of Dietary Additives and Early Feeding on Performance, Gut Development and Immune Status of Broiler Chickens Challenged with Clostridium perfringens  

PubMed Central

The effects of dietary additives and holding time on resistance and resilience of broiler chickens to Clostridium perfringens challenge were investigated by offering four dietary treatments. These were a negative control (basal), a positive control (Zn-bacitracin) and two dietary additives, mannanoligosaccharides (MOS), and acidifier. Two holding times included (a) immediate access to feed and water post hatch (FED) and (b) access to both feed and water 48 h post hatch (HELD). Chicks fed Zn-bacitracin had no intestinal lesions attributed to necrotic enteritis (NE), whereas chicks fed both MOS or acidifier showed signs of NE related lesions. All dietary treatments were effective in reducing the numbers of C. perfringens in the ileum post challenge. The FED chicks had heavier body weight and numerically lower mortality. The FED chicks also showed stronger immune responses to NE challenge, showing enhanced (p<0.05) proliferation of T-cells. Early feeding of the MOS supplemented diet increased (p<0.05) IL-6 production. The relative bursa weight of the FED chicks was heavier at d 21 (p<0.05). All the additives increased the relative spleen weight of the HELD chicks at d 14 (p<0.05). The FED chicks had increased villus height and reduced crypt depth, and hence an increased villus/crypt ratio, especially in the jejunum at d 14 (p<0.05). The same was true for the HELD chicks given dietary additives (p<0.05). It may be concluded that the chicks with early access to dietary additives showed enhanced immune response and gut development, under C. perfringens challenge. The findings of this study shed light on managerial and nutritional strategies that could be used to prevent NE in the broiler industry without the use of in-feed antibiotics. PMID:25049595

Ao, Z.; Kocher, A.; Choct, M.

2012-01-01

195

Occurrence of microbial indicators and Clostridium perfringens in wastewater, water column samples, sediments, drinking water, and Weddell seal feces collected at McMurdo Station, Antarctica  

USGS Publications Warehouse

McMurdo Station, Antarctica, has discharged untreated sewage into McMurdo Sound for decades. Previous studies delineated the impacted area, which included the drinking water intake, by using total coliform and Clostridium perfringens concentrations. The estimation of risk to humans in contact with the impacted and potable waters may be greater than presumed, as these microbial indicators may not be the most appropriate for this environment. To address these concerns, concentrations of these and additional indicators (fecal coliforms, Escherichia coli, enterococci, coliphage, and enteroviruses) in the untreated wastewater, water column, and sediments of the impacted area and drinking water treatment facility and distribution system at McMurdo Station were determined. Fecal samples from Weddell seals in this area were also collected and analyzed for indicators. All drinking water samples were negative for indicators except for a single total coliform-positive sample. Total coliforms were present in water column samples at higher concentrations than other indicators. Fecal coliform and enterococcus concentrations were similar to each other and greater than those of other indicators in sediment samples closer to the discharge site. C. perfringens concentrations were higher in sediments at greater distances from the discharge site. Seal fecal samples contained concentrations of fecal coliforms, E. coli, enterococci, and C. perfringens similar to those found in untreated sewage. All samples were negative for enteroviruses. A wastewater treatment facility at McMurdo Station has started operation, and these data provide a baseline data set for monitoring the recovery of the impacted area. The contribution of seal feces to indicator concentrations in this area should be considered.

Lisle, J.T.; Smith, J.J.; Edwards, D.D.; McFeters, G.A.

2004-01-01

196

Occurrence of Microbial Indicators and Clostridium perfringens in Wastewater, Water Column Samples, Sediments, Drinking Water, and Weddell Seal Feces Collected at McMurdo Station, Antarctica  

PubMed Central

McMurdo Station, Antarctica, has discharged untreated sewage into McMurdo Sound for decades. Previous studies delineated the impacted area, which included the drinking water intake, by using total coliform and Clostridium perfringens concentrations. The estimation of risk to humans in contact with the impacted and potable waters may be greater than presumed, as these microbial indicators may not be the most appropriate for this environment. To address these concerns, concentrations of these and additional indicators (fecal coliforms, Escherichia coli, enterococci, coliphage, and enteroviruses) in the untreated wastewater, water column, and sediments of the impacted area and drinking water treatment facility and distribution system at McMurdo Station were determined. Fecal samples from Weddell seals in this area were also collected and analyzed for indicators. All drinking water samples were negative for indicators except for a single total coliform-positive sample. Total coliforms were present in water column samples at higher concentrations than other indicators. Fecal coliform and enterococcus concentrations were similar to each other and greater than those of other indicators in sediment samples closer to the discharge site. C. perfringens concentrations were higher in sediments at greater distances from the discharge site. Seal fecal samples contained concentrations of fecal coliforms, E. coli, enterococci, and C. perfringens similar to those found in untreated sewage. All samples were negative for enteroviruses. A wastewater treatment facility at McMurdo Station has started operation, and these data provide a baseline data set for monitoring the recovery of the impacted area. The contribution of seal feces to indicator concentrations in this area should be considered. PMID:15574926

Lisle, John T.; Smith, James J.; Edwards, Diane D.; McFeters, Gordon A.

2004-01-01

197

Phospholipase C from Clostridium perfringens stimulates formation and release of platelet-activating factor (PAF-acether) in cultured intestinal epithelial cells (INT 407).  

PubMed

This study demonstrates the ability of phospholipase C from Clostridium perfringens to stimulate the generation of platelet-activating factor (PAF-acether) in cultured intestinal epithelial cells (INT 407). Cells were exposed to phospholipase C for up to 60 min, and the content of PAF-acether within the cells and in the extracellular medium was determined. Phospholipase C caused a time-dependent formation of PAF-acether within the cells and also release of PAF-acether to the medium. In contrast, phospholipase C did not affect the cellular acetylhydrolase activity or the ability of the cells to metabolize extracellularly added 14C-PAF-acether. These findings suggest the possibility that intestinal epithelial cells, when stimulated with a naturally occurring intestinal bacterial toxin, generate and release PAF-acether. The possibility that this might contribute to the pathophysiology of inflammatory bowel disease is discussed. PMID:1947765

Gustafson, C; Kald, B; Sjödahl, R; Tagesson, C

1991-10-01

198

Inhibition of noradrenaline-stimulated lipolysis and cyclic AMP accumulation in isolated rat adipocytes by purified phospholipase C and theta-toxin from Clostridium perfringens.  

PubMed

Purified phospholipae C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) and theta-toxin from Clostridium perfringens both inhibited noradrenaline-stimulated lipolysis and cyclic AMP accumulation in isolated rat adipocytes in a dose-dependent manner. The action of phospholipase C was gradual in onset, while the effect of theta-toxin was almost immediate. Phospholipase C, but not theta-toxin, hydrolyzed membrane phospholipids and inhibited adenylate cyclase (EC 4.6.1.1) in a crude membrane fraction from fat cells. The inhibitory effects of phospholipase C were associated with morphological alterations detectable by electron microscopy, whereas effects of theta-toxin were observed at a time when no clearcut morphological alterations could be observed. It is concluded that the two purified principles from C. perfringens, which are both present in commercial preparations of phospholipase C, antagonize noradrenaline-stimulated cyclic AMP accumulation and lipolysis. Although their exact mechanisms of action have not been elucidated, phospholipase C and theta-toxin have different modes of attack. PMID:203164

Freholm, B B; Möllby, R; Malmquist, T; Smyth, C J

1978-01-01

199

Phospholipase C from Clostridium perfringens stimulates acetyltransferase-dependent formation of platelet-activating factor in cultured intestinal epithelial cells (INT 407).  

PubMed

The mechanisms by which phospholipase C from Clostridium perfringens stimulates the formation of platelet-activating factor (PAF-acether) in cultured intestinal epithelial cells (INT 407) were investigated. Although stimulation with phospholipase C caused a significant formation of PAF-acether, there was no significant increase in the cellular levels of lysoPAF-acether after stimulation. Moreover, when cells prelabeled with 3H-1-O-alkyl-2-acyl-sn-glycerophosphocholine were stimulated with phospholipase C, the 3H-lysoPAF-acether content was not increased in stimulated cells as compared with unstimulated cells. When cells were preincubated with the calmodulin inhibitor trifluoperazine (TFPA), the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), or the combined phospholipase A2-inhibitor and lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) before stimulation with phospholipase C, the PAF-acether formation was significantly decreased. The phospholipase A2 inhibitor 4-bromophenacyl bromide (BPB), on the other hand, had no significant effect on the PAF-acether formation. Preincubation with NDGA also decreased the levels of lysoPAF-acether, whereas BPB, H7, or TFPA had no such effect. These findings indicate that stimulation of acetyltransferase activity with increased acetylation of lysoPAF-acether may be one way by which phospholipase C from C. perfringens stimulates formation of PAF-acether in INT 407 cells. PMID:8209184

Kald, B; Boll, R M; Gustafson-Svärd, C; Sjödahl, R; Tagesson, C

1994-03-01

200

The effect of flavophospholipol (Flavomycin) and salinomycin sodium (Sacox) on the excretion of Clostridium perfringens, Salmonella enteritidis, and Campylobacter jejuni in broilers after experimental infection.  

PubMed

Intestinal colonization and shedding of pathogenic bacteria in animal feces is an important factor in both human food safety and animal health. The effect of broiler feed additives flavophospholipol (FPL; Flavomycin, bambermycins) and salinomycin sodium (SAL; Sacox) given singly on the excretion of Salmonella enteritidis, Campylobacter jejuni, and Clostridium perfringens was studied following controlled infection. The incidence of shedding (number of birds with positive fecal cultures) and the degree of shedding (cfu per gram of feces in positive birds) were measured to determine the influence of these two common feed additive antibiotics on shedding rates of potential pathogens. A total of 216 Ross broiler chickens, housed in battery cages, were fed either an unmedicated feed (controls), feed containing FPL, or feed containing SAL. Feed treatment groups were subdivided into three bacterial challenge groups of 24 chicks, each receiving only one of the pathogens. Bacterial challenge was administered orally on Days 11 and 12 for Salmonella and Campylobacter and on Days 2 and 3 for Clostridium. Fecal samples were collected weekly up to 6 wk of age and cultured for presence of the target organism. The shedding rate was determined by decimal dilutions of the fecal samples. Feeding FPL resulted in a reduced (P < or = 0.05) degree and incidence of Salmonella and Clostridium shedding at 6 wk. Feeding SAL reduced (P < or = 0.05) the incidence of Salmonella shedding at 6 wk. Neither feed additive affected the incidence nor the degree of Campylobacter shedding. The results of this study indicate that these feed additives may reduce the incidence of these potential human and animal pathogens in preslaughter broilers. PMID:10626641

Bolder, N M; Wagenaar, J A; Putirulan, F F; Veldman, K T; Sommer, M

1999-12-01

201

Contributions of NanI Sialidase to Caco-2 Cell Adherence by Clostridium perfringens Type A and C Strains Causing Human Intestinal Disease.  

PubMed

Previous studies showed that Clostridium perfringens type D animal disease strain CN3718 uses NanI sialidase for adhering to enterocyte-like Caco-2 cells. The current study analyzed whether NanI is similarly important when type A and C human intestinal disease strains attach to Caco-2 cells. A PCR survey determined that the nanI gene was absent from typical type A food poisoning (FP) strains carrying a chromosomal enterotoxin (CPE) gene or the genetically related type C Darmbrand (Db) strains. However, the nanI gene was present in type A strains from healthy humans, type A strains causing CPE-associated antibiotic-associated diarrhea (AAD) or sporadic diarrhea (SD), and type C Pig-Bel strains. Consistent with NanI sialidase being the major C. perfringens sialidase when produced, FP and Db strains had little supernatant sialidase activity compared to other type A or C human intestinal strains. All type A and C human intestinal strains bound to Caco-2 cells, but NanI-producing strains had higher attachment levels. When produced, NanI can contribute to host cell attachment of human intestinal disease strains, since a nanI null mutant constructed in type A SD strain F4969 had lower Caco-2 cell adhesion than wild-type F4969 or a complemented strain. Further supporting a role for NanI in host cell attachment, sialidase inhibitors reduced F4969 adhesion to Caco-2 cells. Collectively, these results suggest that NanI may contribute to the intestinal attachment and colonization needed for the chronic diarrhea of CPE-associated AAD and SD, but this sialidase appears to be dispensable for the acute pathogenesis of type A FP or type C enteritis necroticans. PMID:25135687

Li, Jihong; McClane, Bruce A

2014-11-01

202

Growth of Clostridium tertium and Clostridium septicum in chemically defined media.  

PubMed

Defined media for the growth of Clostridium tertium and Clostridium septicum are described. The requirements for growth of these two species are compared with each other and with those of Clostridium perfringens. PMID:180884

Hasan, S M; Hall, J B

1976-03-01

203

LRP1 is a receptor for Clostridium perfringens TpeL toxin indicating a two-receptor model of clostridial glycosylating toxins.  

PubMed

Large glycosylating toxins are major virulence factors of various species of pathogenic Clostridia. Prototypes are Clostridium difficile toxins A and B, which cause antibiotics-associated diarrhea and pseudomembranous colitis. The current model of the toxins' action suggests that receptor binding is mediated by a C-terminal domain of combined repetitive oligopeptides (CROP). This model is challenged by the glycosylating Clostridium perfringens large cytotoxin (TpeL toxin) that is devoid of the CROP domain but still intoxicates cells. Using a haploid genetic screen, we identified LDL receptor-related protein 1 (LRP1) as a host cell receptor for the TpeL toxin. LRP1-deficient cells are not able to take up TpeL and are not intoxicated. Expression of cluster IV of LRP1 is sufficient to rescue toxin uptake in these cells. By plasmon resonance spectroscopy, a KD value of 23 nM was determined for binding of TpeL to LRP1 cluster IV. The C terminus of TpeL (residues 1335-1779) represents the receptor-binding domain (RBD) of the toxin. RBD-like regions are conserved in all other clostridial glycosylating toxins preceding their CROP domain. CROP-deficient C. difficile toxin B is toxic to cells, depending on the RBD-like region (residues 1349-1811) but does not interact with LRP1. Our data indicate the presence of a second, CROP-independent receptor-binding domain in clostridial glycosylating toxins and suggest a two-receptor model for the cellular uptake of clostridial glycosylating toxins. PMID:24737893

Schorch, Björn; Song, Shuo; van Diemen, Ferdy R; Bock, Hans H; May, Petra; Herz, Joachim; Brummelkamp, Thijn R; Papatheodorou, Panagiotis; Aktories, Klaus

2014-04-29

204

Release of Glycoprotein (GP1) from the Tegumental Surface of Taenia solium by Phospholipase C from Clostridium perfringens Suggests a Novel Protein-Anchor to Membranes  

PubMed Central

In order to explore how molecules are linked to the membrane surface in larval Taenia solium, whole cysticerci were incubated in the presence of phospholipase C from Clostridium perfringens (PLC). Released material was collected and analyzed in polyacrylamide gels with sodium dodecyl sulfate. Two major bands with apparent molecular weights of 180 and 43?kDa were observed. Western blot of released material and localization assays in cysticerci tissue sections using antibodies against five known surface glycoproteins of T. solium cysticerci indicated that only one, previously called GP1, was released. Similar localization studies using the lectins wheat-germ-agglutinin and Concanavalin A showed that N-acetyl-D-glucosamine, N-acetylneuraminic, sialic acid, ?methyl-D-mannoside, D-manose/glucose, and N-acetyl-D-glucosamine residues are abundantly present on the surface. On the other hand, we find that treatment with PLC releases molecules from the surface; they do not reveal Cross Reacting Determinant (CRD), suggesting a novel anchor to the membrane for the glycoprotein GP1. PMID:20130782

Landa, Abraham; Willms, Kaethe; Laclette, Juan Pedro

2010-01-01

205

Structural Requirement in Clostridium perfringens Collagenase mRNA 5? Leader Sequence for Translational Induction through Small RNA-mRNA Base Pairing  

PubMed Central

The Gram-positive anaerobic bacterium Clostridium perfringens is pathogenic to humans and animals, and the production of its toxins is strictly regulated during the exponential phase. We recently found that the 5? leader sequence of the colA transcript encoding collagenase, which is a major toxin of this organism, is processed and stabilized in the presence of the small RNA VR-RNA. The primary colA 5?-untranslated region (5?UTR) forms a long stem-loop structure containing an internal bulge and masks its own ribosomal binding site. Here we found that VR-RNA directly regulates colA expression through base pairing with colA mRNA in vivo. However, when the internal bulge structure was closed by point mutations in colA mRNA, translation ceased despite the presence of VR-RNA. In addition, a mutation disrupting the colA stem-loop structure induced mRNA processing and ColA-FLAG translational activation in the absence of VR-RNA, indicating that the stem-loop and internal bulge structure of the colA 5? leader sequence is important for regulation by VR-RNA. On the other hand, processing was required for maximal ColA expression but was not essential for VR-RNA-dependent colA regulation. Finally, colA processing and translational activation were induced at a high temperature without VR-RNA. These results suggest that inhibition of the colA 5? leader structure through base pairing is the primary role of VR-RNA in colA regulation and that the colA 5? leader structure is a possible thermosensor. PMID:23585542

Nomura, Nobuhiko; Nakamura, Kouji

2013-01-01

206

A Synthetic Peptide Corresponding to the Extracellular Loop 2 Region of Claudin-4 Protects against Clostridium perfringens Enterotoxin In Vitro and In Vivo.  

PubMed

Clostridium perfringens enterotoxin (CPE) action starts when the toxin binds to claudin receptors. Claudins contain two extracellular loop domains, with the second loop (ECL-2) being slightly smaller than the first. CPE has been shown to bind to ECL-2 in receptor claudins. We recently demonstrated that Caco-2 cells (a naturally CPE-sensitive enterocyte-like cell line) can be protected from CPE-induced cytotoxicity by preincubating the enterotoxin with soluble full-length recombinant claudin-4 (rclaudin-4), which is a CPE receptor, but not with recombinant nonreceptor claudins, such as rclaudin-1. The current study evaluated whether a synthetic peptide corresponding to the claudin-4 ECL-2 sequence can similarly inhibit CPE action in vitro and in vivo. Significant protection of Caco-2 cells was also observed using either rclaudin-4 or the claudin-4 ECL-2 peptide in both a preincubation assay and a coincubation assay. This inhibitory effect was specific, since rclaudin-1 and a synthetic peptide based on the claudin-1 ECL-2 offered no protection to Caco-2 cells. However, the claudin-4 ECL-2 peptide was unable to neutralize cytotoxicity if CPE had already bound to Caco-2 cells. When the study was repeated in vivo using a rabbit small intestinal loop assay, preincubation or coincubation of CPE with the claudin-4 ECL-2 peptide significantly and specifically inhibited the development of CPE-induced luminal fluid accumulation and histologic lesions in rabbit small intestinal loops. No similar in vivo protection from CPE was afforded by the claudin-1 ECL-2 peptide. These results suggest that claudin-4 ECL-2 peptides should be further investigated for their potential therapeutic application against CPE-associated disease. PMID:25156725

Shrestha, Archana; Robertson, Susan L; Garcia, Jorge; Beingasser, Juliann; McClane, Bruce A; Uzal, Francisco A

2014-11-01

207

In Silico, In Vitro and In Vivo Analysis of Binding Affinity between N and C-Domains of Clostridium perfringens Alpha Toxin  

PubMed Central

Clostridium perfringens alpha toxin/phospholipase C (CP-PLC) is one of the most potent bacterial toxins known to cause soft tissue infections like gas gangrene in humans and animals. It is the first bacterial toxin demonstrated to be an enzyme with phospholipase, sphingomyelinase and lecithinase activities. The toxin is comprised of an enzymatic N-domain and a binding C-domain interconnected by a flexible linker. The N-domain alone is non-toxic to mammalian cells, but incubation with C-domain restores the toxicity, the mechanism of which is still not elucidated. The objectives of the current study were to investigate the formation of a stable N and C-domain complex, to determine possible interactions between the two domains in silico and to characterize the in vitro and in vivo correlates of the interaction. To establish the existence of a stable N and C-domain hybrid, in vitro pull down assay and dot-Far Western blotting assays were employed, where it was clearly revealed that the two domains bound to each other to form an intermediate. Using bioinformatics tools like MetaPPISP, PatchDock and FireDock, we predicted that the two domains may interact with each other through electrostatic interactions between at least six pairs of amino acids. This N and C-domains interacted with each other in 1:1 ratio and the hybrid lysed mouse erythrocytes in a slower kinetics when compared with wild type native Cp-PLC. BALB/c mice when challenged with N and C-domain hybrid demonstrated severe myonecrosis at the site of injection while no death was observed. Our results provide further insight into better understanding the mechanism for the toxicity of Cp-PLC N and C-domain mixture. PMID:24349173

Uppalapati, Siva Ramakrishna; Kingston, Joseph Jeyabalaji; Qureshi, Insaf Ahmed; Murali, Harishchandra Sripathy; Batra, Harsh Vardhan

2013-01-01

208

Eradication of Chemotherapy-Resistant CD44+ Human Ovarian Cancer Stem Cells in Mice by Intraperitoneal Administration of Clostridium Perfringens Enterotoxin  

PubMed Central

BACKGROUND Emerging evidence has suggested that the capability to sustain tumor formation, growth, and chemotherapy resistance in ovarian as well as other human malignancies exclusively resides in a small proportion of tumor cells termed cancer stem cells. During the characterization of CD44+ ovarian cancer stem cells, we found a high expression of the genes encoding for claudin-4. Because this tight junction protein is the natural high-affinity receptor for Clostridium perfringens enterotoxin (CPE), we have extensively investigated the sensitivity of ovarian cancer stem cells to CPE treatment in vitro and in vivo. METHODS Real-time polymerase chain reaction and flow cytometry were used to evaluate claudin-3/-4 expression in ovarian cancer stem cells. Small interfering RNA knockdown experiments and MTS assays were used to evaluate CPE-induced cytotoxicity against ovarian cancer stem cell lines in vitro. C.B-17/SCID mice harboring ovarian cancer stem cell xenografts were used to evaluate CPE therapeutic activity in vivo. RESULTS CD44+ ovarian cancer stem cells expressed claudin-4 gene at significantly higher levels than matched autologous CD44? ovarian cancer cells, and regardless of their higher resistance to chemotherapeutic agents died within 1 hour after exposure to 1.0 ?g/mL of CPE in vitro. Conversely, small-interfering RNA-mediated knockdown of claudin-3/-4 expression in CD44+ cancer stem cells significantly protected cancer stem cells from CPE-induced cytotoxicity. Importantly, multiple intraperitoneal administrations of sublethal doses of CPE in mice harboring xenografts of chemotherapy-resistant CD44+ ovarian cancer stem cells had a significant inhibitory effect on tumor progression leading to the cure and/or long-term survival of all treated animals (ie, 100% reduction in tumor burden in 50% of treated mice; P < .0001). CONCLUSIONS CPE may represent an unconventional, potentially highly effective strategy to eradicate chemotherapy-resistant cancer stem cells. PMID:21692061

Casagrande, Francesca; Cocco, Emiliano; Bellone, Stefania; Richter, Christine E.; Bellone, Marta; Todeschini, Paola; Siegel, Eric; Varughese, Joyce; Arin-Silasi, Dan; Azodi, Masoud; Rutherford, Thomas J.; Pecorelli, Sergio; Schwartz, Peter E.; Santin, Alessandro D.

2013-01-01

209

Raw beef, pork and chicken in Japan contaminated with Salmonella sp., Campylobacter sp., Yersinia enterocolitica, and Clostridium perfringens--a comparative study.  

PubMed

One hundred and twenty samples each of raw ground beef, pork and chicken from ten local grocery stores in Shimane Prefecture, Japan, were examined for the presence of Salmonella sp. (Sal), Campylobacter jejuni (Cj), Campylobacter coli (Cc), Yersinia enterocolitica (Ye), and Clostridium perfringens (Cp) from April 1984 to March 1985. A total of 205 isolates of Sal (112 strains), Cj (64 strains), Cc (one strain), Ye (7 strains) and Cp (21 strains) were recovered from 17 beef (14.2%), 31 pork (25.8%) and 94 chicken (78.3%) of 120 samples each. Sal biogroup 1 was found in 8.3% of beef, 13.3% of pork and 35.0% of chicken, Sal biogroup 2 in 0.8% of beef, 4.2% of pork and 14.2% of chicken, Cj in 1.7% of beef and pork and 50.0% of chicken, Cc in 0.8% of pork, Ye serotype 03 was found in 5.0% of pork, and Cp in 1.7% of beef and pork and 10.8% of chicken. These enteropathogens were recovered concomitantly from two pork and 31 chicken samples, especially Sal and Cj. Sal was counted at less than or equal to 10(2)/100 g of beef and pork and at less than or equal to 10(3)/100 g of chicken, Cj was counted at less than or equal to 10(1)/g of beef and pork and at less than or equal to 10(2)/g of chicken, Ye serotype 03 was counted at less than or equal to 10(3)/g of pork, Cp was counted at less than or equal to 10(2)/g of pork and at less than or equal to 10(2)g of chicken, and Cc from pork and Cp from beef were recovered by using enrichment culture. This investigation showed that a second-contamination of Sal and Cj from chicken to beef and pork frequently occurred during the warm months of the year. It was suggested that chicken may become a source of infection with plural organisms of enteric pathogens, especially Sal and Cj, at the same time all the year round, and that pork may be an important source of infection with Ye during the cold months. PMID:2887078

Fukushima, H; Hoshina, K; Nakamura, R; Ito, Y

1987-04-01

210

The closely related ermB-ermAM genes from Clostridium perfringens, Enterococcus faecalis (pAM beta 1), and Streptococcus agalactiae (pIP501) are flanked by variants of a directly repeated sequence.  

PubMed Central

The Clostridium perfringens macrolide-lincosamide-streptogramin B resistance gene, ermBP, was sequenced and shown to be identical to the ermB-ermAM gene from the promiscuous Enterococcus faecalis plasmid pAM beta 1 and to have at least 98% nucleotide sequence identity to other ermB-ermAM genes. Flanking the ermBP structural gene were almost identical directly repeated 1,341-bp sequences (DR1 and DR2). These repeats potentially encoded a 298 (or 284)-amino-acid protein that had sequence similarity to chromosomal and plasmid partitioning proteins. The pAM beta 1 and Streptococcus agalactiae (pIP501) erm determinants appeared to have DR2 but had similar internal 973- or 956-bp deletions in DR1, respectively. Some of the other ermB-ermAM class determinants had small portions of DR1, but none had complete copies. It is postulated that the C. perfringens ermBP determinant was derived from an enterococcal or streptococcal determinant that had complete copies of both DR1 and DR2. PMID:7486927

Berryman, D I; Rood, J I

1995-01-01

211

Heat resistance and outgrowth of clostridium perfringens spores as affected by the type of heating medium, and heating and cooling rates in ground pork  

E-print Network

) and cured ground pork (CGP) at 75ºC. The effect of the heating rate on HR, germination and outgrowth of C. perfringens spores in CGP was determined by increasing the temperature from 20 to 75ºC at a rate of 4, 8, and 12ºC/h prior to heating and holding at 75...

Marquez Gonzalez, Mayra

2009-05-15

212

Claudin-4 Overexpression in Epithelial Ovarian Cancer Is Associated with Hypomethylation and Is a Potential Target for Modulation of Tight Junction Barrier Function Using a C-Terminal Fragment of Clostridium perfringens Enterotoxin1  

PubMed Central

Background Claudin-4, a tight junction (TJ) protein and receptor for the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), is overexpressed in epithelial ovarian cancer (EOC). Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4-expressing cells. We sought to correlate claudin-4 overexpression in EOC with clinical outcomes and TJ barrier function, investigate DNA methylation as a mechanism for overexpression, and evaluate the effect of C-CPE on the TJ. Methods Claudin-4 expression in EOC was quantified and correlated with clinical outcomes. Claudin-4 methylation status was determined, and claudin-4-negative cell lines were treated with a demethylating agent. Electric cell-substrate impedance sensing was used to calculate junctional (paracellular) resistance (Rb) in EOC cells after claudin-4 silencing and after C-CPE treatment. Results Claudin-4 overexpression in EOC does not correlate with survival or other clinical endpoints and is associated with hypomethylation. Claudin-4 overexpression correlates with Rb and C-CPE treatment of EOC cells significantly decreased Rb in a dose- and claudin-4-dependent noncytotoxic manner. Conclusions C-CPE treatment of EOC cells leads to altered TJ function. Further research is needed to determine the potential clinical applications of C-CPE in EOC drug delivery strategies. PMID:17460774

Litkouhi, Babak; Kwong, Joseph; Lo, Chun-Min; Smedley, James G; McClane, Bruce A; Aponte, Margarita; Gao, Zhijian; Sarno, Jennifer L; Hinners, Jennifer; Welch, William R; Berkowitz, Ross S; Mok, Samuel C; Garner, Elizabeth I O

2007-01-01

213

The Level of Expression of ?-toxin by Different Strains of Clostridium perfringens is Dependent on Differences in Promoter Structure and Genetic Background  

Microsoft Academic Search

The control of expression of the ?-toxin gene (cpaorplc) ofClostridium perfringenshas been studied in three strains shown to have high (NCTC8237), intermediate (strain 13) and low (NCTC8533) phospholipase C activity in the culture supernatant. The phospholipase C activity was shown to be related tocpamRNA levels. Primer extension studies were performed to locate thecpapromoter regions in strains NCTC8237 and 13. Differences

Helen L. Bullifent; Anne Moir; Milena M. Awad; Paul T. Scott; Julian I. Rood; Richard W. Titball

1996-01-01

214

Claudin-4 Overexpression in Epithelial Ovarian Cancer Is Associated with Hypomethylation and Is a Potential Target for Modulation of Tight Junction Barrier Function Using a C-Terminal Fragment of Clostridium perfringens Enterotoxin  

Microsoft Academic Search

BACKGROUND: Claudin-4, a tight junction (TJ) protein and receptor for the C-terminal fragment of Clos- tridium perfringens enterotoxin (C-CPE), is overex- pressed in epithelial ovarian cancer (EOC). Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4- expressing cells. We sought to correlate claudin-4 overexpression in EOC

Babak Litkouhi; Joseph Kwong; Chun-Min Lo; James G. Smedley III; Bruce A. McClane; Margarita Aponte; Zhijian Gao; Jennifer L. Sarno; Jennifer Hinners; William R. Welch; Ross S. Berkowitz; Samuel C. Mok; Elizabeth I. O. Garner

2007-01-01

215

The Effect of Intra-Arterial Hydrogen Peroxide in Rabbits Infected with Clostridum Perfringens.  

National Technical Information Service (NTIS)

Clostridial myositis was produced in 48 rabbits by injection of a Clostridium perfringens-epinephrine preparation into the left thigh. Twenty-four of these rabbits were treated with intermittent infusions of 0.18 per cent hydrogen peroxide in normal salin...

B. E. Bradley, N. A. Vedros, A. J. Defalco, D. W. Lawson, H. C. Urschel

1965-01-01

216

Clostridium bacteraemia characterised by 16S ribosomal RNA gene sequencing  

PubMed Central

Background: Owing to problems in accurate species identification of the diverse genus clostridium, the epidemiology and pathogenicity of many species are not fully understood. Moreover, previous studies on clostridium bacteraemia have been limited and relied only on phenotypic species identification. Aims: To characterise the epidemiology, disease spectrum, and outcome of clostridium bacteraemia using 16S ribosomal RNA (rRNA) gene sequencing. Method: During a four year period (1998–2001), all cases of clostridium bacteraemia were prospectively studied and all “non-perfringensclostridium isolates identified to the species level by 16S rRNA gene sequencing. Results: Fifty one blood culture isolates were identified as Clostridium perfringens and 17 belonged to 11 other clostridium species. The first case of C disporicum infection and two cases of clostridium bacteraemia in children with intussusception were also described. Of the 68 clostridium isolates from 68 different patients, 38 were associated with clinically relevant bacteraemia. The gastrointestinal and hepatobiliary tracts were common sites of both underlying disease and portal of entry in these patients. Clostridium perfringens accounted for 79% of all clinically relevant bacteraemia, with the remainder caused by a diversity of species. The attributable mortality rate of clinically relevant clostridium bacteraemia was 29%. Younger age and underlying gastrointestinal/hepatobiliary tract disease were associated with mortality (p < 0.05). Conclusions: Patients with clinically relevant clostridium bacteraemia should be investigated for the presence of underlying disease processes in the gastrointestinal or hepatobiliary tracts. 16S rRNA gene analysis will continue to be useful in further understanding the pathogenicity of various clostridium species. PMID:15735165

Woo, P C Y; Lau, S K P; Chan, K-m; Fung, A M Y; Tang, B S F; Yuen, K-y

2005-01-01

217

Detection and quantification of four species of the genus Clostridium in infant feces.  

PubMed

To determine the composition of Clostridium in the feces of infants approximately 30 days old, we have developed a detection and quantification method of Clostridium paraputrificum, Clostridium perfringens, Clostridium tertium, and Clostridium difficile by species-specific primers. C. perfringens and C. difficile were detected in four fecal samples from 22 infants (18.2%), whereas C. paraputrificum was detected in three samples (16.7%). C. tertium was detected in two samples (9.1%). Moreover, the occurrences of the four species in bottle-and mix-fed infants were relatively higher than in breast-fed infants (P< 0.05). Subsequently, positive samples detected by nested PCR (polymerase chain reaction) were subjected to realtime PCR. The results showed that the numbers of C. paraputrificum, C. perfringens, C. tertium, and C. difficile ranged from about 1x10(5) to 3x10(7) cells/g wet feces. PMID:16301809

Tonooka, Toshiki; Sakata, Shinji; Kitahara, Maki; Hanai, Michio; Ishizeki, Shinobu; Takada, Masaaki; Sakamoto, Mitsuo; Benno, Yoshimi

2005-01-01

218

Polymicrobial septic arthritis due to Clostridium species: case report and review.  

PubMed

Clostridium species are capable of producing several types of infectious processes, many of which have proven to be life-threatening. Septic arthritis caused by Clostridium, however, is not a very frequent finding. Currently, only 37 cases of infectious arthritis due to Clostridium species have been reported. We report a case of septic arthritis in which Clostridium perfringens, Clostridium sordellii, and Clostridium tertium were each isolated from the synovial aspirate. In addition, the 37 previously reported cases are summarized to compare the similarities and differences of the clinical course, treatment, and outcome, in order to help establish guidelines for the proper management of this infectious process. PMID:10722451

Gredlein, C M; Silverman, M L; Downey, M S

2000-03-01

219

Characterization of the Enzymatic Component of the ADP-Ribosyltransferase Toxin CDTa from Clostridium difficile  

Microsoft Academic Search

Certain strains of Clostridium difficile produce the ADP-ribosyltransferase CDT, which is a binary actin ADP-ribosylating toxin. The toxin consists of the binding component CDTb, which mediates receptor binding and cellular uptake, and the enzyme component CDTa. Here we studied the enzyme component (CDTa) of the toxin using the binding component of Clostridium perfringens iota toxin (Ib), which is interchangeable with

IRENE GULKE; GUNTHER PFEIFER; JAN LIESE; MICHAELA FRITZ; FRED HOFMANN; KLAUS AKTORIES; HOLGER BARTH

2001-01-01

220

Dissimilatory nitrate reduction in Clostridium tertium.  

PubMed

Fermentation balance studies were carried out on Clostridium tertium grown with and without nitrate in the medium. Nitrate reduction increased the efficiency of energy produced from glucose by permitting the utilization of additional sites of substrate level phosphorylation. The effect was even more dramatic in C. tertium than in C. perfringens, with increased cell yields of about 30% being observed in the former compared with 20% in the latter. Unlike C. perfringens, C. tertium responded to the presence of nitrate in the medium with an increased growth rate. A slight increase in the Y ATP of these cultures was also observed, and quantitatively, this appeared to be consistent with the prediction of Stouthammer and Bettenhaussen that Y ATP will vary with the growth rate. Thus, C. tertium, like C. perfringens, was able to use nitrate as an electron acceptor in conjunction with its energy metabolism, suggesting that this may be widespread among the nitrate-reducing anaerobes. PMID:203129

Hasan, M; Hall, J B

1977-01-01

221

Experimental reproduction of neonatal diarrhea in young gnotobiotic hares simultaneously associated with Clostridium difficile and other Clostridium strains.  

PubMed

Clostridium difficile, C. perfringens, and C. tertium are very often present simultaneously in the feces of conventional diarrheic young hares, whereas these three bacterial species are rarely encountered and never present simultaneously in the feces of healthy young hares. When a strain of each of the three bacterial species was monoassociated with axenic young hares, the appearance of pathological disorders was only observed in animals monoassociated with C. difficile, when the number of C. difficile exceeded 10(8) per g of fresh feces. When a strain of C. perfringens or a strain of C. tertium, or both, was associated with C. difficile, diarrhea and death occurred more rapidly than in hares monoassociated with C. difficile. C. difficile and C. perfringens became established more rapidly when disassociated than when monoassociated with axenic hares. The association of C. perfringens and C. tertium with axenic hares did not bring about any pathological disorders. It may be concluded that C. difficile is the causal agent of neonatal diarrhea in conventional and gnotobiotic young hares and that other strains of Clostridium enhance its pathogenic effect. C difficile alone or associated with C. perfringens or C. tertium does not play any pathogenic role in young rats, mice, or rabbits. PMID:222683

Dabard, J; Dubos, F; Martinet, L; Ducluzeau, R

1979-04-01

222

Germination induction and inactivation of Clostridium spores at medium-range hydrostatic pressure treatment  

Microsoft Academic Search

Germination-inductions and inactivation, following pressurization of four Clostridium species\\/strains between 138 and 483 MPa at 25° and 50 °C, were studied. Germination-inductions ranged between <1% and 99%. Pressurization at 483 MPa and 50 °C for 5 min inactivated C. tertium spores by over 2.5 log cycles; under similar conditions, inactivation of three other Clostridium species, namely C. perfringens, C. sporogenes

N. Kalchayanand; C. P. Dunne; A. Sikes; B. Ray

2004-01-01

223

How to measure epsilon'/epsilon with lattice QCD  

SciTech Connect

A pedagogical discussion is given of a lattice calculation of epsilon'. The method is outlined, and preliminary results are presented. They suggest that epsilon'/epsilon may be reduced from previous estimates by 60-70%.

Sharpe, S.R.

1987-04-01

224

Synthesis and evaluation of a non-radioactive gene probe for the detection of C.perfringens alpha toxin.  

PubMed

The synthesis and evaluation of a non-radioactive hybridization probe is described, specific detecting the Clostridium perfringens alphatoxin gene (plc) by colony blot hybridization assay. A vector free digoxigenin-dUTP-labelled probe was generated by polymerase chain reaction (PCR) targeting the cloned plc gene of C.perfringens strain ATCC 13124. In a colony blot hybridization assay 296 strains of C.perfringens were tested for plc. None of the strains failed in hybridization. Presence of plc was even demonstrated in C.perfringens strains reported to lack lecithinase activity. Specificity of the probe was shown with various strains of other bacterial species. None different Clostridia sp. tested, e.g. C.bifermentans, C.tertium, C.novyi, C.chauvoei, C.sporogenes, C.difficile, C.putrifucum, C.sordellii, C.botulinum, C. septicum and C.histolyticum, hybridized with the plc specific probe. Strains expressing an enzymatically related phospholipase like Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus gave also negative results. Comparing the results of conventionally used egg yolk turbidity assay and those gained with DNA hybridization, the plc probe proved to be a much more sensitive and specific diagnostic tool for the detection of C.perfringens plc. PMID:7603469

Schlapp, T; Blaha, I; Bauerfeind, R; Wieler, L H; Schoepe, H; Weiss, R; Baljer, G

1995-04-01

225

Clostridium difficile  

Microsoft Academic Search

\\u000a \\u000a Clostridium difficile produces gastrointestinal infection in humans and animals, ranging from asymptomatic colonization to diarrhea, pseudomembranous\\u000a colitis, toxic megacolon, colonic perforation, sepsis, and death. C. difficile has emerged as a major cause of nosocomial diarrhea and is the most frequently identified cause of hospital-acquired infectious\\u000a diarrhea in patients.(1,2) C. difficile-associated disease (CDAD) is a general term used to describe the

Dale N. Gerding; Stuart Johnson

226

Antibacterial activity against Clostridium genus and antiradical activity of the essential oils from different origin.  

PubMed

In the present study, the antimicrobial and antiradical activities of 15 essential oils were investigated. The antimicrobial activities were determined by using agar disc diffusion and broth microdilution methods against Clostridium genus and antioxidant properties of essential oils by testing their scavenging effect on DPPH radicals activities. We determined the antibacterial activity of Clostridium butyricum, Clostridium hystoliticum, Clostridium intestinale, Clostridium perfringens and Clostridium ramosum. We obtained the original commercial essential oils samples of Lavandula angustifolia, Carum carvi, Pinus montana, Mentha piperita, Foeniculum vulgare Mill., Pinus sylvestris, Satureia montana, Origanum vulgare L. (2 samples), Pimpinella anisum, Rosmarinus officinalis L., Salvia officinalis L., Abies alba Mill., Chamomilla recutita L. Rausch and Thymus vulgaris L. produced in Slovakia (Calendula a.s., Nova Lubovna, Slovakia). The results of the disk diffusion method showed very high essential oils activity against all tested strains of microorganisms. The best antimicrobial activity against C. butyricum was found at Pimpinella anisum, against C. hystoliticum was found at Pinus sylvestris, against C. intestinale was found at Satureia hortensis L., against C. perfringens was found at Origanum vulgare L. and against C. ramosum was found at Pinus sylvestris. The results of broth microdilution assay showed that none of the essential oils was active against C. hystoliticum. The best antimicrobial activity against C. butyricum was found at Abies alba Mill., against C. intestinale was found at Abies alba Mill., against C. perfringens was found at Satureia montana and against C. ramosum was found at Abius alba and Carum carvi. Antioxidant DPPH radical scavenging activity was determined at several solutions of oil samples (50 ?L.mL(-1)-0.39 ?L.mL(-1)) and the best scavenging effect for the highest concentration (50 ?L.mL(-1)) was observed. The antioxidant properties were different in particular plant species. The highest% of inhibition after 30 min. of reaction was observed at Origanum vulgare (93%), Satureia montana (90.66%) and Lavandula augustifolia (90.22%). PMID:24813985

Ka?ániová, Miroslava; Vukovi?, Nenad; Horská, Elena; Salamon, Ivan; Bobková, Alica; Hleba, Lukáš; Fiskelová, Martina; Vat?ák, Alexander; Petrová, Jana; Bobko, Marek

2014-01-01

227

Clostridium and bacillus binary enterotoxins: bad for the bowels, and eukaryotic being.  

PubMed

Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (?-toxin and binary enterotoxin, or BEC), Clostridium spiroforme (C. spiroforme toxin or CST), as well as Bacillus cereus (vegetative insecticidal protein or VIP). These gut-acting proteins form an AB complex composed of ADP-ribosyl transferase (A) and cell-binding (B) components that intoxicate cells via receptor-mediated endocytosis and endosomal trafficking. Once inside the cytosol, the A components inhibit normal cell functions by mono-ADP-ribosylation of globular actin, which induces cytoskeletal disarray and death. Important aspects of each bacterium and binary enterotoxin will be highlighted in this review, with particular focus upon the disease process involving the biochemistry and modes of action for each toxin. PMID:25198129

Stiles, Bradley G; Pradhan, Kisha; Fleming, Jodie M; Samy, Ramar Perumal; Barth, Holger; Popoff, Michel R

2014-09-01

228

Clostridium and Bacillus Binary Enterotoxins: Bad for the Bowels, and Eukaryotic Being  

PubMed Central

Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (?-toxin and binary enterotoxin, or BEC), Clostridium spiroforme (C. spiroforme toxin or CST), as well as Bacillus cereus (vegetative insecticidal protein or VIP). These gut-acting proteins form an AB complex composed of ADP-ribosyl transferase (A) and cell-binding (B) components that intoxicate cells via receptor-mediated endocytosis and endosomal trafficking. Once inside the cytosol, the A components inhibit normal cell functions by mono-ADP-ribosylation of globular actin, which induces cytoskeletal disarray and death. Important aspects of each bacterium and binary enterotoxin will be highlighted in this review, with particular focus upon the disease process involving the biochemistry and modes of action for each toxin. PMID:25198129

Stiles, Bradley G.; Pradhan, Kisha; Fleming, Jodie M.; Samy, Ramar Perumal; Barth, Holger; Popoff, Michel R.

2014-01-01

229

Quark masses, B-parameters, and CP violation parameters {epsilon} and {epsilon}{prime}/{epsilon}  

SciTech Connect

After a brief introduction to lattice QCD, the author summarizes the results for the light quark masses and the bag parameters B{sub K}, B{sub 6}{sup 1/2}, and B{sub 8}{sup 3/2}. The implications of these results for the standard model estimates of CP violation parameters {epsilon} and {epsilon}{prime}/{epsilon} are also discussed.

Gupta, R.

1998-01-20

230

Actin-specific ADP-ribosyltransferase produced by a Clostridium difficile strain.  

PubMed Central

By screening possible ADP-ribosyltransferase activities in culture supernatants from various Clostridium species, we have found one Clostridium difficile strain (CD196) (isolated in our laboratory) that is able to produce, in addition to toxins A and B, a new ADP-ribosyltransferase that was shown to covalently modify cell actin as Clostridium botulinum C2 or Clostridium perfringens E iota toxins do. The molecular weight of the CD196 ADP-ribosyltransferase (CDT) was determined to be 43 kilodaltons, and its isoelectric point was 7.8. No cytotoxic activity on Vero cells or lethal activity upon injection in mice was associated with this enzyme. CDT was neither related to C. difficile A or B toxins nor to C. botulinum C2 toxin component I. However, Vero cells cultivated in the presence of C. difficile B toxin had a lower amount of actin able to be ADP-ribosylated by CDT or C2 toxin in vitro. Antibodies raised against CDT reacted by immunoblot analysis with a 43-kilodalton protein of C. perfringens type E culture supernatant producing the iota toxin. Images PMID:3137166

Popoff, M R; Rubin, E J; Gill, D M; Boquet, P

1988-01-01

231

Quantitative real-time PCR assay for Clostridium septicum in poultry gangrenous dermatitis associated samples.  

PubMed

Clostridium septicum is a spore-forming anaerobe frequently implicated in cases of gangrenous dermatitis (GD) and other spontaneously occurring myonecrotic infections of poultry. Although C. septicum is readily cultured from diseased tissues it can be difficult to enumerate due to its tendency to swarm over the surface of agar plates. In this study a quantitative real-time PCR assay was developed in order to more accurately measure the levels of C. septicum in healthy as well as GD associated poultry samples. The assay was specifically designed to target the C. septicum alpha toxin gene, csa, which is, to our knowledge, carried by all strains of C. septicum and has been shown to be essential for virulence. Genomic DNAs from a diverse collection of bacterial species, including closely related Clostridium chauvoei, Clostridium carnis, Clostridium tertium as well as several strains of Clostridium perfringens, all failed to produce a positive reaction. An approximate reproducible limit of detection in spiked extracts of at least 10(3) cfu/g of C. septicum was observed for a variety of different sample types. C. septicum levels in broiler chicken field samples estimated from the results of qPCR were statistically correlated to culture based enumerations obtained from those same tissues. PMID:20399850

Neumann, A P; Dunham, S M; Rehberger, T G; Siragusa, G R

2010-08-01

232

Clostridium botulinum type E occurs and grows in the alga Cladophora glomerata  

USGS Publications Warehouse

In recent years, massive avian die-offs from Clostridium botulinum type E infection have occurred in the Sleeping Bear Dunes National Lakeshore (SLBE) area of Lake Michigan. These outbreaks have been coincidental with massive blooms of the green algae Cladophora, mostly Cladophora glomerata. We tested the hypothesis that Clostridium botulinum type E can grow under suitable conditions in these algal mats. In a lab mesocosm study, Cladophora from four outbreak-impacted beaches from SLBE were compared with four unimpacted beaches in the Milwaukee–Racine area for bontE gene of Clostridium botulinum. Frequency of the bontE gene was higher after incubation (25 °C for up to 6 weeks) of Cladophora from impacted vs. the unimpacted area. Since no type E gene was detected initially in Cladophora from any of the eight locations, we infer that the increased occurrence of type E gene arose from spore germination or vegetative Clostridium growth within the existing algal mats of SLBE. Moreover, we found that the congener Clostridium perfringens readily grows in mesocosms containing Cladophora.

Byappanahalli, M. N.; Whitman, R. L.

2009-01-01

233

Gas discharge plasmas are effective in inactivating Bacillus and Clostridium spores.  

PubMed

Bacterial spores are the most resistant form of life and have been a major threat to public health and food safety. Nonthermal atmospheric gas discharge plasma is a novel sterilization method that leaves no chemical residue. In our study, a helium radio-frequency cold plasma jet was used to examine its sporicidal effect on selected strains of Bacillus and Clostridium. The species tested included Bacillus subtilis, Bacillus stearothermophilus, Clostridium sporogenes, Clostridium perfringens, Clostridium difficile, and Clostridium botulinum type A and type E. The plasmas were effective in inactivating selected Bacillus and Clostridia spores with D values (decimal reduction time) ranging from 2 to 8 min. Among all spores tested, C. botulinum type A and C. sporogenes were significantly more resistant to plasma inactivation than other species. Observations by phase contrast microscopy showed that B. subtilis spores were severely damaged by plasmas and the majority of the treated spores were unable to initiate the germination process. There was no detectable fragmentation of the DNA when the spores were treated for up to 20 min. The release of dipicolinic acid was observed almost immediately after the plasma treatment, indicating the spore envelope damage could occur quickly resulting in dipicolinic acid release and the reduction of spore resistance. PMID:22075631

Tseng, Shawn; Abramzon, Nina; Jackson, James O; Lin, Wei-Jen

2012-03-01

234

Regulation of toxin and bacteriocin synthesis in Clostridium species by a new subgroup of RNA polymerase sigma-factors.  

PubMed

Many Clostridium species are pathogenic for humans and animals, and most of the resulting diseases, such as tetanus, botulism, gas gangrene and pseudomembranous colitis, are due to the production of potent extracellular toxins. The biochemical mechanisms of action of Clostridium toxins have been extensively studied in the past ten years. However, detailed information about the regulation of toxin gene expression has only recently emerged. TcdR, BotR, TetR and UviA are now known to be related alternative RNA polymerase sigma factors that drive transcription of toxin A and toxin B genes in C. difficile, the neurotoxin genes in C. botulinum and C. tetani, and a bacteriocin gene in C. perfringens. Although the Clostridium sigma factors have some similarity to members of the ECF sigma factor group, they differ sufficiently in structure and function so that they have been assigned to a new group within the sigma(70)-family. PMID:16439101

Dupuy, Bruno; Matamouros, Susana

2006-04-01

235

Clostridium Difficile Infections  

MedlinePLUS

Clostridium difficile (C. difficile) is a bacterium that causes diarrhea and more serious intestinal conditions such as colitis. Symptoms include Watery ... Nausea Abdominal pain or tenderness You might get C. difficile disease if you have an illness that ...

236

Tailored Cyclodextrin Pore Blocker Protects Mammalian Cells from Clostridium difficile Binary Toxin CDT  

PubMed Central

Some Clostridium difficile strains produce, in addition to toxins A and B, the binary toxin Clostridium difficile transferase (CDT), which ADP-ribosylates actin and may contribute to the hypervirulence of these strains. The separate binding and translocation component CDTb mediates transport of the enzyme component CDTa into mammalian target cells. CDTb binds to its receptor on the cell surface, CDTa assembles and CDTb/CDTa complexes are internalised. In acidic endosomes, CDTb mediates the delivery of CDTa into the cytosol, most likely by forming a translocation pore in endosomal membranes. We demonstrate that a seven-fold symmetrical positively charged ?-cyclodextrin derivative, per-6-S-(3-aminomethyl)benzylthio-?-cyclodextrin, which was developed earlier as a potent inhibitor of the translocation pores of related binary toxins of Bacillus anthracis, Clostridium botulinum and Clostridium perfringens, protects cells from intoxication with CDT. The pore blocker did not interfere with the CDTa-catalyzed ADP-ribosylation of actin or toxin binding to Vero cells but inhibited the pH-dependent membrane translocation of CDTa into the cytosol. In conclusion, the cationic ?-cyclodextrin could serve as the lead compound in a development of novel pharmacological strategies against the CDT-producing strains of C. difficile. PMID:25029374

Roeder, Maurice; Nestorovich, Ekaterina M.; Karginov, Vladimir A.; Schwan, Carsten; Aktories, Klaus; Barth, Holger

2014-01-01

237

Tailored cyclodextrin pore blocker protects mammalian cells from clostridium difficile binary toxin CDT.  

PubMed

Some Clostridium difficile strains produce, in addition to toxins A and B, the binary toxin Clostridium difficile transferase (CDT), which ADP-ribosylates actin and may contribute to the hypervirulence of these strains. The separate binding and translocation component CDTb mediates transport of the enzyme component CDTa into mammalian target cells. CDTb binds to its receptor on the cell surface, CDTa assembles and CDTb/CDTa complexes are internalised. In acidic endosomes, CDTb mediates the delivery of CDTa into the cytosol, most likely by forming a translocation pore in endosomal membranes. We demonstrate that a seven-fold symmetrical positively charged ?-cyclodextrin derivative, per-6-S-(3-aminomethyl)benzylthio-?-cyclodextrin, which was developed earlier as a potent inhibitor of the translocation pores of related binary toxins of Bacillus anthracis, Clostridium botulinum and Clostridium perfringens, protects cells from intoxication with CDT. The pore blocker did not interfere with the CDTa-catalyzed ADP-ribosylation of actin or toxin binding to Vero cells but inhibited the pH-dependent membrane translocation of CDTa into the cytosol. In conclusion, the cationic ?-cyclodextrin could serve as the lead compound in a development of novel pharmacological strategies against the CDT-producing strains of C. difficile. PMID:25029374

Roeder, Maurice; Nestorovich, Ekaterina M; Karginov, Vladimir A; Schwan, Carsten; Aktories, Klaus; Barth, Holger

2014-07-01

238

Relationship between gastrointestinal dysbiosis and Clostridium botulinum in dairy cows.  

PubMed

The gastrointestinal tract is a balanced ecosystem that can get out of balance and predisposed to clostridial diseases or other pathological conditions. The objective of the present study was to evaluate the gut microbiota in dairy cows suffering from chronic botulism. Cows were investigated for Clostridium (C.) botulinum in faeces and rumen fluids. In order to study the relationship between botulism and gastrointestinal microbiota, faeces and rumen fluid were tested for bacterial composition using conventional microbiological culture techniques and fluorescence in situ hybridization (FISH). Protozoa were analyzed in rumen fluid microscopically. The presence of C. botulinum was associated with specific changes in the faecal microbiota, especially a significant reduction of total aerobic bacteria, total anaerobic bacteria, enterococci, Clostridium perfringens and yeast and fungi. Also C. botulinum positive rumen fluid had significantly more Bacteroides spp., C. histolyticum group, Alfa- proteobacteria, Gammaproteobacteria, and sulfate-reducing bacteria; as well as significantly fewer Euryaracheota, and the protozoa Epidinium spp. Dasytricha spp., Diplodiniinae spp. and Ophryoscolex spp. In conclusion, C. botulinum is common in dairy cows in Germany but the incidence of botulism is associated with microbial changes and composition in the gastrointestinal tract. Bacteria, yeast and protozoa appear to be crucial in the colonization process; however, the chronology of these events and role of each microbial group needs further evaluation. PMID:24747040

Krüger, Monika; Shehata, Awad A; Grosse-Herrenthey, Anke; Ständer, Norman; Schrödl, Wieland

2014-06-01

239

DIARRHEA IN ONE TO THREE WEEK-OLD PIGLETS ASSOCIATED WITH CLOSTRIDIUM PERFRINGENS TYPE A.  

E-print Network

contents of severely affected animals. Experimental infec- tions with hysterectomy derived, colostrum. coli and other gram negative pathogens. Virological examination for rotavirus was carried out on ELISA6 were made by testing ten fold dilutions on TSDC. Three to five black colonies from the highest dilution

Paris-Sud XI, Université de

240

Raffinose increases sporulation and enterotoxin production by Clostridium perfringens type A.  

PubMed Central

Replacement of starch with raffinose in Duncan and Strong sporulation medium improved percent sporulation in six of eight strains tested. Enterotoxin concentration in cell extracts was increased in the case of four of five known enterotoxin-positive strains. With strain NCTC 10240, levels of 0.3, 0.4, and 0.5% raffinose produced the highest enterotoxin concentration 300 to 320 micrograms of enterotoxin per mg of cell extract protein. At a level of 0.4% raffinose the highest enterotoxin concentration in cell extracts of NCTC 10240 occurred after 8 h of growth in Duncan and Strong medium. Enterotoxin produced in the presence of starch or raffinose by three separate strains all migrated at similar Rm by polyacrylamide gel electrophoresis. Images PMID:225991

Labbe, R G; Rey, D K

1979-01-01

241

Enteritis associated with Clostridium perfringens type A in 9-month-old calves  

PubMed Central

Four 9-month-old Simmental male calves were presented with a history of sudden death. The necropsy and microscopic findings allowed a diagnosis of enteritis and severe intraluminal hemorrhage with blood clots in the jejunum, suggestive of jejunal hemorrhage syndrome. PMID:22851779

Savic, Bozidar; Prodanovic, Radisa; Ivetic, Vojin; Radanovic, Oliver; Bojkovski, Jovan

2012-01-01

242

The induction of toxin neutralizing antibodies to Clostridium perfringens types C and D toxins in horses  

E-print Network

hemorrhagic enterotoxemia of calves, foals, lambs and piglets; and necrotic enteritis of man and fowl. Type D is probably the most ldlyk pthg I C. ~fi ~ typ, lt1 th tl agent of fatal enterotoxemia of sheep ("overeat1ng disease" or "pulpy kidney d1sease... was not isolated from rabbits involved in a serious outbreak of enteritis, the presence of the pre-formed iota toxin was confirmed by neutralization tests. Type E has also been implicated in hemorrhagic necrot1c enteritis of calves in Australia. It seems that a...

Brooks, Frances Lynn

2012-06-07

243

Inhibitory Effects of Collagen on the PCR for Detection of Clostridium perfringens  

Microsoft Academic Search

It is essential to identify specific food components that inhibit PCR in order to increase the sensitivity of the PCR method for rapid detection of pathogens contaminating a food. We found that collagen, a major component of several foods, inhibited PCR. The inhibitory action of collagen on PCR could be partially reversed by adjusting the concentration of magnesium ion in

SANGBURM KIM; RONALD G. LABBE; SANGRYEOL RYU

2000-01-01

244

Clostridium tetani bacteraemia.  

PubMed

Tetanus is a neuromuscular disease in which Clostridium tetani exotoxin (tetanospasmin) produces muscle spasms, incapacitating its host. To our knowledge, C. tetani bacteraemia has never been reported in the literature. The ideal management of this entity remains unresolved given that there is no literature to guide the therapy. PMID:22977074

Hallit, Rabih Riad; Afridi, Muhammad; Sison, Raymund; Salem, Elie; Boghossian, Jack; Slim, Jihad

2013-01-01

245

The search for companions to Epsilon Eridani.  

PubMed

The authors review efforts to examine the star Epsilon Eridani and determine the possibility for the existence of an Earth-like planet. Early data indicated that there must be a habitable ecosphere about 82.5 million Km from the primary. Research into the existence of another planetary system determined that Epsilon Eridani was a binary star with an Oort cloud system, indicating the possibility of planet formation. A review of the evidence suggests that the presence of the small red Dwarf companion star precludes the existence of a planetary system surrounding Epsilon Eridani. It is suggested that observations continue to provide further data about the formation of binary systems. PMID:11540498

Lawton, A T; Wright, P

1990-12-01

246

Characterization of the enzymatic component of the ADP-ribosyltransferase toxin CDTa from Clostridium difficile.  

PubMed

Certain strains of Clostridium difficile produce the ADP-ribosyltransferase CDT, which is a binary actin ADP-ribosylating toxin. The toxin consists of the binding component CDTb, which mediates receptor binding and cellular uptake, and the enzyme component CDTa. Here we studied the enzyme component (CDTa) of the toxin using the binding component of Clostridium perfringens iota toxin (Ib), which is interchangeable with CDTb as a transport component. Ib was used because CDTb was not expressed as a recombinant protein in Escherichia coli. Similar to iota toxin, CDTa ADP-ribosylates nonmuscle and skeletal muscle actin. The N-terminal part of CDTa (CDTa1-240) competes with full-length CDTa for binding to the iota toxin binding component. The C-terminal part (CDTa244-263) harbors the enzyme activity but was much less active than the full-length CDTa. Changes of Glu428 and Glu430 to glutamine, Ser388 to alanine, and Arg345 to lysine blocked ADP-ribosyltransferase activity. Comparison of CDTa with C. perfringens iota toxin and Clostridium botulinum C2 toxin revealed full enzyme activity of the fragment Ia208-413 but loss of activity of several N-terminally deleted C2I proteins including C2I103-431, C2I190-431, and C2I30-431. The data indicate that CDTa belongs to the iota toxin subfamily of binary actin ADP-ribosylating toxins with respect to interaction with the binding component and substrate specificity. It shares typical conserved amino acid residues with iota toxin and C2 toxin that are suggested to be involved in NAD-binding and/or catalytic activity. The enzyme components of CDT, iota toxin, and C2 toxin differ with respect to the minimal structural requirement for full enzyme activity. PMID:11553537

Gülke, I; Pfeifer, G; Liese, J; Fritz, M; Hofmann, F; Aktories, K; Barth, H

2001-10-01

247

Clostridium difficile colitis.  

PubMed

Clostridium difficile enterocolitis is endemic in most modern hospitals. The spectrum of clinical presentation varies from the asymptomatic carrier state to fulminant colitis with toxic megacolon and perforation. Highly toxigenic and lethal strains of C. difficile have emerged worldwide. Medical treatment consists of discontinuing the precipitating antibiotic, supportive measures and bowel rest, and antibiotic treatment with metronidazole or vancomycin. Surgical treatment may be necessary in cases of fulminant disease. Subtotal colectomy with end ileostomy is the operation of choice. PMID:20011356

Trudel, Judith L

2007-02-01

248

Update on Clostridium difficile  

Microsoft Academic Search

Opinion statement  The most dramatic change in the past several years has been the increased incidence and severity of Clostridium difficile colitis reported from multiple countries. A number of factors have likely contributed to this. One major event has been the\\u000a emergence of a fluoroquinolone-resistant clone of C. difficile with enhanced virulence properties that is associated with epidemic disease. Also noteworthy

Cheleste M. Thorpe; Sherwood L. Gorbach

2006-01-01

249

Clostridium difficile infection  

PubMed Central

Clostridium difficile infection (CDI) is the primary cause of antibiotic-associated diarrhea and is a significant nosocomial disease. In the past ten years, variant toxin-producing strains of C. difficile have emerged, that have been associated with severe disease as well as outbreaks worldwide. This review summarizes current information on C. difficile pathogenesis and disease, and highlights interventions used to combat single and recurrent episodes of CDI. PMID:21327030

Viswanathan, VK; Mallozzi, MJ

2010-01-01

250

Regulation of toxin and bacteriocin gene expression in Clostridium by interchangeable RNA polymerase sigma factors.  

PubMed

The production of major extracellular toxins by pathogenic strains of Clostridium botulinum, Clostridium tetani and Clostridium difficile, and a bacteriocin by Clostridium perfringens is dependent on a related group of RNA polymerase sigma-factors. These sigma-factors (BotR, TetR, TcdR and UviA) were shown to be sufficiently similar that they could substitute for one another in in vitro DNA binding and run-off transcription experiments. In cells, however, the sigma-factors fell into two subclasses. BotR and TetR were able to direct transcription of their target genes in a fully reciprocal manner. Similarly, UviA and TcdR were fully interchangeable. Neither BotR nor TetR could substitute for UviA or TcdR, however, and neither UviA nor TcdR could direct transcription of the natural targets of BotR or TetR. The extent of functional interchangeability of the sigma-factors was attributed to the strong conservation of their subregion 4.2 sequences and the conserved -35 sequences of their target promoters, while restrictions on interchangeability were attributed to variations in their subregion 2.4 sequences and the target site -10 sequences. The four sigma-factors have been assigned to group 5 of the sigma(70) family and seem to have arisen from a common ancestral protein that may have co-evolved with the genes whose transcription they direct. A fifth Clostridiumsigma-factor, sigma(Y) of Clostridium acetobutylicum, resembles the TcdR family, but was not functionally interchangeable with members of this family. PMID:16677313

Dupuy, Bruno; Raffestin, Stéphanie; Matamouros, Susana; Mani, Nagraj; Popoff, Michel R; Sonenshein, Abraham L

2006-05-01

251

Clostridium tertium: 3 case reports.  

PubMed

Clostridium tertium is infrequently isolated from blood in patients with underlying diseases. Laboratory diagnosis is often delayed because Clostridium tertium is aerotolerant and resistant to metronidazole. Clinically it is a problem because it is commonly resistant to metronidazole, clindamycin and cephalosporins. We present 3 cases illustrating these characteristics. PMID:15849058

Leegaard, Truls M; Sandven, Per; Gaustad, Peter

2005-01-01

252

Molecular dynamics simulations for pure epsilon-CL-20 and epsilon-CL-20-based PBXs.  

PubMed

Molecular dynamics has been employed to simulate the well-known high energy density compound epsilon-CL-20 (hexanitrohexaazaisowurtzitane) crystal and 12 epsilon-CL-20-based PBXs (polymer bonded explosives) with four kinds of typical fluorine polymers, i.e., polyvinylidenedifluoride, polychlorotrifluoroethylene, fluorine rubber (F(2311)), and fluorine resin (F(2314)) individually. The elastic coefficients, isotropic mechanical properties (tensile moduli, bulk moduli, shear moduli, and poission's ratios), and bonding energy are first reported for epsilon-CL-20 crystal and epsilon-CL-20-based polymer bonded explosives (PBXs). The mechanical properties of epsilon-CL-20 can be effectively improved by blending with a small amount of fluorine polymers, and the whole effect of the adding fluorine polymers to improve mechanical properties of PBXs along the three crystalline surfaces of epsilon-CL-20 is found to be (100) approximately (001) > (010). The interaction between each of the crystalline surfaces and each of the fluorine polymers is different, and the ordering of binding energy for the three surfaces is (001) > (100) > (010); F(2314) always has the strongest binding ability with the three different surfaces. F(2314) can best improve the ductibility and tenacity of PBX when it is positioned on epsilon-CL-20 (001) crystal surface. The calculations on detonation performances for pure epsilon-CL-20 crystal and the four epsilon-CL-20-based PBXs show that adding a small amount of fluorine polymer into pure epsilon-CL-20 will lower detonation performance, but each detonation parameter of the obtained PBXs is still excellent. PMID:16599487

Xu, Xiao-Juan; Xiao, He-Ming; Xiao, Ji-Jun; Zhu, Wei; Huang, Hui; Li, Jin-Shan

2006-04-13

253

The genome sequence of Clostridium tetani, the causative agent of tetanus disease  

PubMed Central

Tetanus disease is one of the most dramatic and globally prevalent diseases of humans and vertebrate animals, and has been reported for over 24 centuries. The manifestation of the disease, spastic paralysis, is caused by the second most poisonous substance known, the tetanus toxin, with a human lethal dose of ?1 ng/kg. Fortunately, this disease is successfully controlled through immunization with tetanus toxoid; nevertheless, according to the World Health Organization, an estimated 400,000 cases still occur each year, mainly of neonatal tetanus. The causative agent of tetanus disease is Clostridium tetani, an anaerobic spore-forming bacterium, whose natural habitat is soil, dust, and intestinal tracts of various animals. Here we report the complete genome sequence of toxigenic C. tetani E88, a variant of strain Massachusetts. The genome consists of a 2,799,250-bp chromosome encoding 2,372 ORFs. The tetanus toxin and a collagenase are encoded on a 74,082-bp plasmid, containing 61 ORFs. Additional virulence-related factors could be identified, such as an array of surface-layer and adhesion proteins (35 ORFs), some of them unique to C. tetani. Comparative genomics with the genomes of Clostridium perfringens, the causative agent of gas gangrene, and Clostridium acetobutylicum, a nonpathogenic solvent producer, revealed a remarkable capacity of C. tetani: The organism can rely on an extensive sodium ion bioenergetics. Additional candidate genes involved in the establishment and maintenance of a pathogenic lifestyle of C. tetani are presented. PMID:12552129

Bruggemann, Holger; Baumer, Sebastian; Fricke, Wolfgang Florian; Wiezer, Arnim; Liesegang, Heiko; Decker, Iwona; Herzberg, Christina; Martinez-Arias, Rosa; Merkl, Rainer; Henne, Anke; Gottschalk, Gerhard

2003-01-01

254

Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii  

PubMed Central

The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C. ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis. PMID:24509933

Ueki, Toshiyuki; Nevin, Kelly P.; Lovley, Derek R.

2014-01-01

255

Expression of Clostridium difficile Toxins A and B and Their Sigma Factor TcdD Is Controlled by Temperature  

PubMed Central

Growth temperature was found to control the expression of toxins A and B in Clostridium difficile VPI 10463, with a maximum at 37°C and low levels at 22 and 42°C in both peptone yeast (PY) and defined media. The up-regulation of toxin A and B mRNA and protein levels upon temperature upshift from 22 to 37°C followed the same kinetics, showing that temperature control occurred at the level of transcription. Experiments with Clostridium perfringens using gusA as a reporter gene demonstrated that both toxin gene promoters were temperature controlled and that their high activity at 37°C was dependent on the alternative sigma factor TcdD. Furthermore, tcdD was found to be autoinduced at 37°C. Glucose down-regulated all these responses in the C. perfringens constructs, similar to its impact on toxin production in C. difficile PY broth cultures. C. difficile proteins induced at 37°C and thus coregulated with the toxins by temperature were demonstrated by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified as enzymes involved in butyric acid production and as electron carriers in oxidation-reduction reactions. The regulation of toxin production in C. difficile by temperature is a novel finding apparently reflecting an adaptation of the expression of its virulence to mammalian hosts. PMID:12654792

Karlsson, Sture; Dupuy, Bruno; Mukherjee, Kakoli; Norin, Elisabeth; Burman, Lars G.; Akerlund, Thomas

2003-01-01

256

Comparative In Vitro Activities of LFF571 against Clostridium difficile and 630 Other Intestinal Strains of Aerobic and Anaerobic Bacteria  

PubMed Central

The in vitro activities of LFF571, a novel analog of GE2270A that inhibits bacterial growth by binding with high affinity for protein synthesis elongation factor Tu, fidaxomicin, and 10 other antimicrobial agents were determined against 50 strains of Clostridium difficile and 630 other anaerobic and aerobic organisms of intestinal origin. LFF571 possesses potent activity against C. difficile and most other Gram-positive anaerobes (MIC90, ?0.25 ?g/ml), with the exception of bifidobacteria and lactobacilli. The MIC90s for aerobes, including enterococci, Staphylococcus aureus (as well as methicillin-resistant S. aureus [MRSA] isolates), Streptococcus pyogenes, and other streptococci were 0.06, 0.125, 2, and 8 ?g/ml, respectively. Comparatively, fidaxomicin showed variable activity against Gram-positive organisms: MIC90s against C. difficile, Clostridium perfringens, and Bifidobacterium spp. were 0.5, ?0.015, and 0.125 ?g/ml, respectively, but >32 ?g/ml against Clostridium ramosum and Clostridium innocuum. MIC90 for S. pyogenes and other streptococci was 16 and >32 ?g/ml, respectively. LFF571 and fidaxomicin were generally less active against Gram-negative anaerobes. PMID:22290948

Tyrrell, Kerin L.; Merriam, C. Vreni; Goldstein, Ellie J. C.

2012-01-01

257

Request for additional epsilon Aurigae observations  

NASA Astrophysics Data System (ADS)

Dr. Robert Stencel (Denver U.) requests enhanced coverage of the bright, long-period eclipsing binary star epsilon Aurigae through Wednesday. Observations are requested beginning immediately (October 29, 2009; JD 2455134) and continuing through November 5, 2009 (JD 2455141). This request is in conjunction with scheduled observations with the CHARA optical interferometer at Mount Wilson in California. Optical photometry by a number of observers will provide a continuous photometric baseline of epsilon Aurigae during the course of the interferometry, enabling Stencel and collaborators to more easily interpret the interferometric images. These interferometric observations are being made to image the system as it enters eclipse; the optical interferometric observations being made by CHARA are completely analogous to those made with radio interferometers like the Very Large Array, and allow ground based observers to obtain images with far higher resolution than a single optical telescope is capable of. The CHARA observations are scheduled for the nights of November 1, 2, and 3 (through mid-day UT on November 4, 2009). All observations, including visual estimates, DSLR and CCD photometry, and photoelectric photometry, are encouraged. The observations are part of a larger, long-term collaborative effort to study epsilon Aurigae. For more information on epsilon Aurigae, see the Citizen Sky website http://www.citizensky.org/. Epsilon Aurigae is currently in the ingress phase of the eclipse, which likely began in August of 2009. The star is now near V ~ 3.4 and declining. The nature of the eclipsing object is not known, but is likely to be an opaque disk surrounding an unseen, massive secondary star or binary pair. Interferometric images of epsilon Aurigae may yield strong constraints on the shape of the eclipsing! disk and size of the system. Observations should be reported to the AAVSO International Database as EPS AUR.

Templeton, Matthew R.

2009-10-01

258

Clostridium difficile Infection  

PubMed Central

Clostridium difficile is the leading cause of hospital-acquired diarrhea in Europe and North America and is a serious re-emerging pathogen. Recent outbreaks have led to increasing morbidity and mortality and have been associated with a new strain (BI/NAP1/027) of C. difficile that produces more toxin than historical strains. With the increasing incidence of C. difficile infection, clinicians have also seen a change in the epidemiology with increased infections in previously low-risk populations. This chapter highlights the current knowledge on C. difficile virulence, human disease, epidemic outbreaks, and optimal treatment strategies. PMID:20697257

Heinlen, Latisha; Ballard, Jimmy D.

2010-01-01

259

Bifidobacterium, Bacteroides, and Clostridium spp. in fecal samples from breast-fed and bottle-fed infants with and without iron supplement.  

PubMed

Bifidobacterium, Bacteroides, and Clostridium spp. isolated from the feces of 23 neonates during the first 3 months of life were identified. Of the 23 neonates, 10 were breast fed, 6 received an infant formula with iron supplement (5 mg/liter), and 7 received the formula without iron supplement (iron concentration, less than 0.5 mg/liter). The Bifidobacterium spp. most frequently isolated from the three groups of infants were B. longum, B. breve, B. adolescentis, and B. bifidum. The bacteroides spp. most frequently isolated were B. fragilis and B. vulgatus. The most common Clostridium sp. in the three groups of infants was C. perfringens. The type of milk did not select for species of Bifidobacterium, Bacteroides, or Clostridium, except for Clostridium butyricum, which was isolated significantly more often from bottle-fed infants with iron supplement than from the other groups, and Clostridium tertium, which was more often isolated from breast-fed infants. The species of the three anaerobic genera did not persist for a long period of time in the three groups of infants. PMID:3818925

Mevissen-Verhage, E A; Marcelis, J H; de Vos, M N; Harmsen-van Amerongen, W C; Verhoef, J

1987-02-01

260

Evaluation of 16S rRNA Gene Restriction Analysis for the Identification of Cultured Organisms of Clinically Important Clostridium Species  

Microsoft Academic Search

In order to evaluate the usefulness of restriction analysis of the amplified 16S rRNA gene for the genotypic identification of culturedClostridiumorganisms, a collection of a total of 52 isolates belonging to the following 19 species was studied:Clostridium bifermentans(n = 4),C. butyricum(3),C. cadaveris(3),C. clostridioforme(2),C. difficile(3),C. ghonii(2),C. glycolicum(3),C, histolyticum(3),C. innocuum(3),C. novyiA (1),C. paraputrificum(3),C. perfringens(3),C. ramosum(3),C. septicum(3),C. tetani(3),C. sordelli(3),C. sporogenes(3),C. subterminale(1), andC. tertium(3).

Mario Vaneechoutte; Charles P. Cartwright; Esther C. Williams; Birgit Jäger; Hans-Volker Tichy; Thierry De Baere; Ann De Rouck; Gerda Verschraegen

1996-01-01

261

Antagonistic Effect on Clostridium botulinum Type E by Organisms Resembling It  

PubMed Central

A bacteriocin-like substance, active against strains of Clostridium botulinum type E, is produced by certain nontoxic organisms whose biochemical properties and morphological characteristics are similar to type E. The substance, for which the name “boticin E” is proposed, is bacteriolytic for vegetative cells and bacteriostatic for spores of type E. Its spectrum of activity is somewhat strain-specific. Of the clostridial species tested, only C. botulinum type E and, to a lesser extent, C. perfringens and C. acetobutylicum, but not C. botulinum types A, B, or F, are sensitive. Irreversibly resistant variants originating from both vegetative cells and spores of certain strains were obtained. The active substance is heat-stable and dialyzable, and is not inactivated by chloroform but is digested by trypsin. Ethyl alcohol and acetone precipitates are fully active, whereas trichloroacetic acid precipitates are only partially active. Other nontoxic organisms producing similar antagonistic substances are discussed. PMID:4288828

Kautter, D. A.; Harmon, S. M.; Lynt, R. K.; Lilly, T.

1966-01-01

262

Solubility of (epsilon)-CL-20 in selected materials.  

National Technical Information Service (NTIS)

Solubility of the epsilon polymorph of CL-20 was determined in thirteen liquids over temperature range ambient to 74C using high performance liquid chromatography. The experiments included (epsilon)-CL-20 produced by two different synthesis routes; one lo...

E. von Holtz, D. Ornellas, M. F. Foltz, J. E. Clarkson

1992-01-01

263

BotR/A and TetR are alternative RNA polymerase sigma factors controlling the expression of the neurotoxin and associated protein genes in Clostridium botulinum type A and Clostridium tetani.  

PubMed

Clostridium botulinum and Clostridium tetani, respectively, produce potent toxins, botulinum neurotoxin (BoNT) and tetanus neurotoxin (TeTx), which are responsible for severe diseases, botulism and tetanus. Neurotoxin synthesis is a regulated process in Clostridium. The genes botR/A in C. botulinum A and tetR in C. tetani positively regulate expression of BoNT/A and associated non-toxic proteins (ANTPs), as well as TeTx respectively. The botR/A gene lies in close vicinity of the two operons which contain bont/A and antps genes in C. botulinum A, and tetR immediately precedes the tetX gene in C. tetani. We show that BotR/A and TetR function as specific alternative sigma factors rather than positive regulators based on the following results: (i) BotR/A and TetR associated with target DNAs only in the presence of the RNA polymerase core enzyme (Core), (ii) BotR/A and TetR directly bound with the core enzyme, (iii) BotR/A-Core recognized -35 and -10 regions of ntnh-bont/A promoter and (iv) BotR/A and TetR triggered in vitro transcription from the target promoters. In C. botulinum A, bont/A and antps genes are transcribed as bi- and tricistronic operons controlled by BotR/A. BotR/A and TetR are seemingly related to a new subgroup of the sigma70 family that includes TcdR and UviA, which, respectively, regulate production of toxins A and B in C. difficile and bacteriocin in C. perfringens. Sequences of -35 region are highly conserved in the promoter of target toxin genes in C. botulinum, C. tetani, C. difficile and C. perfringens. Overall, a common regulation mechanism probably controls toxin gene expression in these four toxigenic clostridial species. PMID:15612931

Raffestin, Stéphanie; Dupuy, Bruno; Marvaud, Jean Christophe; Popoff, Michel R

2005-01-01

264

Clostridium absonum alpha-toxin: new insights into clostridial phospholipase C substrate binding and specificity.  

PubMed

Clostridium absonum phospholipase C (Caa) is a 42.7 kDa protein, which shows 60% amino acid sequence identity with the Clostridium perfringens phospholipase C, or alpha-toxin (Cpa), and has been isolated from patients suffering from gas gangrene. We report the cloning and sequencing, purification, characterisation and crystal structure of the Caa enzyme. Caa had twice the phospholipid-hydrolysing (lecithinase) activity, 1.5 times the haemolytic activity and over seven times the activity towards phosphatidylcholine-based liposomes when compared with Cpa. However, the Caa enzyme had a lower activity than Cpa to the free (i.e. not in lipid bilayer) substrate para-nitrophenylphosphorylcholine, towards sphingomyelin-based liposomes and showed half the cytotoxicity. The lethal dose (LD(50)) of Caa in mice was approximately twice that of Cpa. The crystal structure of Caa shows that the 72-93 residue loop is in a conformation different from those of previously determined open-form alpha-toxin structures. This conformational change suggests a role for W84 in membrane binding and a possible route of entry into the active site along a hydrophobic channel created by the re-arrangement of this loop. Overall, the properties of Caa are compatible with a role as a virulence-determinant in gas gangrene caused by C.absonum. PMID:14568535

Clark, Graeme C; Briggs, David C; Karasawa, Tadahiro; Wang, Xingmin; Cole, Ambrose R; Maegawa, Tsuneo; Jayasekera, Pramukh N; Naylor, Claire E; Miller, Julie; Moss, David S; Nakamura, Shinichi; Basak, Ajit K; Titball, Richard W

2003-10-31

265

Epsilon Aur monitoring during predicted pulsation phase  

NASA Astrophysics Data System (ADS)

Dr. Robert Stencel (University of Denver Astronomy Program) has requested that AAVSO observers monitor epsilon Aurigae from now through the end of the observing season. "Studies of the long-term, out-of-eclipse photometry of this enigmatic binary suggest that intervals of coherent pulsation occur at roughly 1/3 of the 27.1-year orbital period. Kloppenborg, et al. noted that stable variation patterns develop at 3,200-day intervals' implying that 'the next span of dates when such events might happen are circa JD ~2457000 (2014 December)'. "These out-of-eclipse light variations often have amplitudes of ~0.1 magnitude in U, and ~0.05 in V, with characteristic timescales of 60-100 days. The AAVSO light curve data to the present may indicate that this coherent phenomenon has begun, but we encourage renewed efforts by observers...to help deduce whether these events are internal to the F star, or externally-driven by tidal interaction with the companion star." Nightly observations or one observation every few days (CCD/PEP/DSLR, VUBR (amplitude too small for visual)) are requested. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. Epsilon Aur was the subject of major international campaigns and the AAVSO's Citizen Sky project as it went through its 27.1-year eclipse in 2009-2011. Over 700 observers worldwide submitted over 20,000 multicolor observations to the AAVSO International Database for this project. Much information on eps Aur is available from the AAVSO, including material on the Citizen Sky website (http://www.aavso.org/epsilon-aurigae and http://www.citizensky.org/content/star-our-project). The Journal of the AAVSO, Volume 40, No. 2 (2012) was devoted to discussion of and research results from this event. See full Alert Notice for more details and observations.

Waagen, Elizabeth O.; Templeton, Matthew R.

2014-09-01

266

The Final Measurement of Epsilon'/Epsilon from KTeV  

SciTech Connect

The authors present precise measurements of CP and CPT symmetry based on the full dataset of K {yields} {pi}{pi} decays collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This dataset contains about 15 million K {yields} {pi}{sup 0}{pi}{sup 0} and 70 million K {yields} {pi}{sup +}{pi}{sup -} decays. They measure the direct CP violation parameter Re({epsilon}'/{epsilon}) = (19.2 {+-} 2.1) x 10{sup -4}. they find the K{sub L}-K{sub S} mass difference {Delta}m = (5265 {+-} 10) x 10{sup 6} {bar h}s{sup -1} and the K{sub S} lifetime {tau}{sub S} = (89.62 {+-} 0.05) x 10{sup -12} s. They test CPT symmetry by finding the phase of the indirect CP violation parameter {epsilon}, {phi}{sub {epsilon}} = (44.09 {+-} 1.00){sup o}, and the difference of the relative phases between the CP violating and CP conserving decay amplitudes for K {yields} {pi}{sup +}{pi}{sup -} ({phi}{sub +-}) and for K {yields} {pi}{sup 0}{pi}{sup 0} ({phi}{sub 00}), {Delta}{phi} = (0.29 {+-} 0.31){sup o}. these results are consistent with other experimental results and with CPT symmetry.

Worcester, E.T.

2009-10-01

267

Viability of Clostridium sporogenes spores after CaO hygienization of meat waste.  

PubMed

The occurrence of the pathogenic species C. perfringens and C. botulinum spores in animal by-products poses a potential epidemiological hazard. Strong entero- and neurotoxins produced by these bacteria adversely affect human health. To inactivate pathogens present in animal by-products, waste must be subjected to various methods of sanitization. The aim of the presented study was to estimate the effect of different doses of CaO on the viability of spores Clostridium sporogenes in meat wastes category 3. During the research, two doses of burnt lime were added to the poultry mince meat and meat mixed with swine blood contaminated with Clostridium sporogenes spore suspension. Half of the samples collected for microbiological analyses were buffered to achieve the pH level ~7, the other were examined without pH neutralization. To estimate the spore number, 10-fold dilution series in peptone water was prepared and heat-treated at 80 °C for 10 min. After cooling-down, one milliliter of each dilution was pour-plated onto DRCM medium solidified with agar. Statistical analysis were performed using the Statistica software. Application of 70% CaO caused complete inactivation of Clostridium spores in meat wastes after 48 hours. The highest temperature achieved during the experiment was 67 °C. Rapid alkalization of the biomass resulted in increasing pH to values exceeding 12. The effect of liming was not dependent on the meat wastes composition nor CaO dose. The experiment proved the efficiency of liming as a method of animal by-products sanitization. Application of the obtained results may help reduce the epidemiological risk and ensure safety to people handling meat wastes at each stage of their processing and utilization. PMID:25292114

Bauza-Kaszewska, Justyna; Paluszak, Zbigniew; Skowron, Krzysztof

2014-09-01

268

Clostridium difficile-associated diarrhoea  

Microsoft Academic Search

Clostridium difficile infection is responsible for approximately 3 million cases of diarrhea and colitis annually in the United States. The mortality rate is 1 to 2.5 percent. Early diagnosis and prompt aggressive treatment are critical in managing C. difficile-associated diarrhea. Major predisposing factors for symptomatic C. difficile colitis include antibiotic therapy; advanced age; multiple, severe underlying diseases; and a faulty

R BRETTLE; E WALLACE

1984-01-01

269

Study on the Complex of Soluble Proteins in the Cells of Clostridium Perfringens by Electrophoresis in Polyacrylanide Gel (O Komplekse Rastvorimykh Belkov, Soderzhashchikhsya V Kletke Clostridium Pereringens).  

National Technical Information Service (NTIS)

The method of electrophoresis in polyacrylamide gel is suitable for separating soluble acid cell proteins. The proteins are separated into a great many sharply demarcated zones and the resultant 'protein spectra' are analyzed. As a rule, the strains of C....

S. A. Nikolaeva, V. I. Safonov

1970-01-01

270

Salmonella spp., Vibrio spp., Clostridium perfringens , and Plesiomonas shigelloides in Marine and Freshwater Invertebrates from Coastal California Ecosystems  

Microsoft Academic Search

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land–sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ecosystems in central California. A variety of filter-feeding clams, mussels, worms, and crab tissues were selectively cultured

W. A. Miller; M. A. Miller; I. A. Gardner; E. R. Atwill; B. A. Byrne; S. Jang; M. Harris; J. Ames; D. Jessup; D. Paradies; K. Worcester; A. Melli; P. A. Conrad

2006-01-01

271

A Study of Epsilon Canis Majoris (B2II)  

Microsoft Academic Search

We propose to obtain high quality LETG observations of the B giant Epsilon Canis Majoris (B2II). These observations will be analyzed together with available optical, IUE, EUVE, and XMM data. Epsilon Canis Majoris is one of only two early-type stars detected in the EUV (lambda < 900Ang) with the NASA Extreme Ultraviolet Explorer (EUVE) satellite, and is the main photoionization

John Hillier

2005-01-01

272

Epsilon Canis Majoris and the ionization of the local cloud  

Microsoft Academic Search

The Lyman continuum radiation from the brightest extreme ultraviolet (EUV) source, the B2 II star epsilon Canis Majoris (Adara), is so intense that it dominates the local stellar EUV radiation field at wavelengths longer than 450 A and therefore sets a lower limit to the ionization of hydrogen in the Local Cloud. Using the EUV (70-730 A) spectrum of epsilon

J. V. Vallerga; B. Y. Welsh

1995-01-01

273

Can It Safely Clostridium botulinum  

E-print Network

H of low-acid foods is too high to prevent the growth of Clostridium botulinum, the organism responsible-acid foods. High-acid foods have a pH of 4.6 or less. High-acid foods naturally prevent C. botulinum spore is the only safe method for preserving low-acid foods. Low-acid foods have a pH greater than 4.6. The p

Liskiewicz, Maciej

274

Electrophoretic study of Clostridium species.  

PubMed Central

Polyacrylamide gel electrophoretic analysis of soluble cellular proteins (without sodium dodecyl sulfate) of 70 Clostridium species indicated that the procedure was readily applicable to the differentiation of species in the genus. The protein patterns correlated well with the available DNA homology data and with most accepted differential tests. Results indicated that several earlier names for species were synonyms of those of accepted species and that two accepted species may be synonymous. Images PMID:6175658

Cato, E P; Hash, D E; Holdeman, L V; Moore, W E

1982-01-01

275

Clostridium difficile-associated colitis.  

PubMed Central

OBJECTIVE: To review the basic microbiology, pathogenesis of disease, and diagnosis of the nosocomial pathogen Clostridium difficile and to examine therapies recommended by the Canadian Task Force on Preventive Health Care. QUALITY OF EVIDENCE MEDLINE: was searched using MeSH headings. Controlled trials for therapy were sought, but case-control studies and observational reviews were included. MAIN MESSAGE: Clostridium difficile causes approximately 20% of cases of diarrhea associated with antibiotics, including clindamycin and the second- and third-generation cephalosporins. Diarrhea is usually mild, but can be severe; extreme cases develop toxic megacolon. Diagnosis is dependent on demonstrating presence of clostridial toxin in stool specimens or of pseudomembranes through sigmoidoscopy. First-line therapy for C. difficile diarrhea is restricted to metronidazole. Second-line therapy for treatment failure is vancomycin. For relapse, a second course of metronidazole is recommended; tapering courses of vancomycin and probiotics are used for multiple recurrences. CONCLUSION: Clostridium difficile is an important nosocomial pathogen requiring prudent use of antibiotics and strict infection-control policies to prevent large health care costs. PMID:15597970

Hull, Mark W.; Beck, Paul L.

2004-01-01

276

Equivalence of History and Generator Epsilon-Machines  

E-print Network

Epsilon-machines are minimal, unifilar presentations of stationary stochastic processes. They were originally defined in the history machine sense, as hidden Markov models whose states are the equivalence classes of infinite pasts with the same probability distribution over futures. In analyzing synchronization, though, an alternative generator definition was given: unifilar, edge-emitting hidden Markov models with probabilistically distinct states. The key difference is that history epsilon-machines are defined by a process, whereas generator epsilon-machines define a process. We show here that these two definitions are equivalent in the finite-state case.

Nicholas F. Travers; James P. Crutchfield

2011-11-18

277

VARIABILITY IN OPTICAL SPECTRA OF {epsilon} ORIONIS  

SciTech Connect

We present the results of a time series analysis of 130 echelle spectra of {epsilon} Ori (B0 Ia), acquired over seven observing seasons between 1998 and 2006 at Ritter Observatory. The equivalent widths of H{alpha} (net) and He I {lambda}5876 were measured and radial velocities were obtained from the central absorption of He I {lambda}5876. Temporal variance spectra (TVS) revealed significant wind variability in both H{alpha} and He I {lambda}5876. The He I TVS have a double-peaked profile consistent with radial velocity oscillations. A periodicity search was carried out on the equivalent width and radial velocity data, as well as on wavelength-binned spectra. This analysis has revealed several periods in the variability with timescales of two to seven days. Many of these periods exhibit sinusoidal modulation in the associated phase diagrams. Several of these periods were present in both H{alpha} and He I, indicating a possible connection between the wind and the photosphere. Due to the harmonic nature of these periods, stellar pulsations may be the origin of some of the observed variability. Periods on the order of the rotational period were also detected in the He I line in the 1998-1999 season and in both lines during the 2004-2005 season. These periods may indicate rotational modulation due to structure in the wind.

Thompson, Gregory B. [Department of Physics, Adrian College, Adrian, MI 49221 (United States); Morrison, Nancy D., E-mail: gthompson@adrian.edu, E-mail: nmorris@utnet.utoledo.edu [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft, Toledo, OH 43606 (United States)

2013-04-15

278

EPSILON AURIGAE: AN IMPROVED SPECTROSCOPIC ORBITAL SOLUTION  

SciTech Connect

A rare eclipse of the mysterious object {epsilon} Aurigae will occur in 2009-2011. We report an updated single-lined spectroscopic solution for the orbit of the primary star based on 20 years of monitoring at the CfA, combined with historical velocity observations dating back to 1897. There are 518 new CfA observations obtained between 1989 and 2009. Two solutions are presented. One uses the velocities outside the eclipse phases together with mid-times of previous eclipses, from photometry dating back to 1842, which provide the strongest constraint on the ephemeris. This yields a period of 9896.0 {+-} 1.6 days (27.0938 {+-} 0.0044 years) with a velocity semi-amplitude of 13.84 {+-} 0.23 km s{sup -1} and an eccentricity of 0.227 {+-} 0.011. The middle of the current ongoing eclipse predicted by this combined fit is JD 2,455,413.8 {+-} 4.8, corresponding to 2010 August 5. If we use only the radial velocities, we find that the predicted middle of the current eclipse is nine months earlier. This would imply that the gravitating companion is not the same as the eclipsing object. Alternatively, the purely spectroscopic solution may be biased by perturbations in the velocities due to the short-period oscillations of the supergiant.

Stefanik, Robert P.; Torres, Guillermo; Lovegrove, Justin; Latham, David W.; Zajac, Joseph [Harvard-Smithsonian Center for Astrophysics (CfA), 60 Garden Street, Cambridge, MA 02138 (United States); Pera, Vivian E. [MIT Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420 (United States); Mazeh, Tsevi [Wise Observatory, Tel Aviv University, Tel Aviv 69978 (Israel)], E-mail: rstefanik@cfa.harvard.edu

2010-03-15

279

Structural Basis for Substrate Recognition in the Enzymatic Component of ADP-ribosyltransferase Toxin CDTa from Clostridium difficile  

PubMed Central

ADP-ribosylation is one of the favored modes of cell intoxication employed by several bacteria. Clostridium difficile is recognized to be an important nosocomial pathogen associated with considerable morbidity and attributable mortality. Along with its two well known toxins, Toxin A and Toxin B, it produces an ADP-ribosylating toxin that targets monomeric actin of the target cell. Like other Clostridial actin ADP-ribosylating toxins, this binary toxin, known as C. difficile toxin (CDT), is composed of two subunits, CDTa and CDTb. In this study, we present high resolution crystal structures of CDTa in its native form (at pH 4.0, 8.5, and 9.0) and in complex with ADP-ribose donors, NAD and NADPH (at pH 9.0). The crystal structures of the native protein show “pronounced conformational flexibility” confined to the active site region of the protein and “enhanced” disorder at low pH, whereas the complex structures highlight significant differences in “ligand specificity” compared with the enzymatic subunit of a close homologue, Clostridium perfringens iota toxin. Specifically in CDTa, two of the suggested catalytically important residues (Glu-385 and Glu-387) seem to play no role or a less important role in ligand binding. These structural data provide the first detailed information on protein-donor substrate complex stabilization in CDTa, which may have implications in understanding CDT recognition. PMID:19692332

Sundriyal, Amit; Roberts, April K.; Shone, Clifford C.; Acharya, K. Ravi

2009-01-01

280

INFRARED STUDIES OF EPSILON AURIGAE IN ECLIPSE  

SciTech Connect

We report here on a series of medium resolution spectro-photometric observations of the enigmatic long period eclipsing binary epsilon Aurigae, during its eclipse interval of 2009-2011, using near-infrared spectra obtained with SpeX on the Infrared Telescope Facility (IRTF), mid-infrared spectra obtained with BASS on AOES and IRTF, MIRSI on IRTF, and MIRAC4 on the MMT, along with mid-infrared photometry using MIRSI on IRTF and MIRAC4 on the MMT, plus 1995-2000 timeframe published photometry and data obtained with Denver's TNTCAM2 at WIRO. The goals of these observations included: (1) comparing eclipse depths with prior eclipse data, (2) confirming the re-appearance of CO absorption bands at and after mid-eclipse, associated with sublimation in the disk, (3) seeking evidence for any mid-infrared solid state spectral features from particles in the disk, and (4) providing evidence that the externally irradiated disk has azimuthal temperature differences. IR eclipse depths appear similar to those observed during the most recent (1983) eclipse, although evidence for post-mid-eclipse disk temperature increase is present, due to F star heated portions of the disk coming into view. Molecular CO absorption returned 57 days after nominal mid-eclipse, but was not detected at mid-eclipse plus 34 days, narrowing the association with differentially heated sub-regions in the disk. Transient He I 10830A absorption was detected at mid-eclipse, persisting for at least 90 days thereafter, providing a diagnostic for the hot central region. The lack of solid-state features in Spitzer Infrared Spectrograph, BASS, and MIRAC spectra to date suggests the dominance of large particles (micron-sized) in the disk. Based on these observations, mid-infrared studies out of eclipse can directly monitor and map the disk thermal changes, and better constrain disk opacity and thermal conductivity.

Stencel, Robert E.; Kloppenborg, Brian K.; Wall, Randall E. [Department of Physics and Astronomy, University of Denver, Denver, CO 80208 (United States); Hopkins, Jeffrey L. [Hopkins Phoenix Observatory, Phoenix, AZ 85033 (United States); Howell, Steve B. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Hoard, D. W. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Rayner, John; Bus, Schelte; Tokunaga, Alan [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Sitko, Michael L.; Bradford, Suellen [Department of Physics, Cincinnati University, Cincinnati, OH (United States); Russell, Ray W.; Lynch, David K. [Aerospace Corporation, Los Angeles, CA 90009 (United States); Hammel, Heidi; Whitney, Barbara [Space Science Institute, Boulder, CO 80301 (United States); Orton, Glenn; Yanamandra-Fisher, Padma [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Hora, Joseph L. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Hinz, Philip; Hoffmann, William, E-mail: rstencel@du.edu [Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); and others

2011-11-15

281

Copolymers of epsilon-caprolactone and quaternized epsilon-caprolactone as gene carriers.  

PubMed

New copolymers of epsilon-caprolactone (CL) and gamma-bromo-epsilon-caprolactone quaternized by pyridine (Py+CL) were investigated as non-viral vectors for gene delivery. Copolymers with two molar compositions (50 Py+CL/50 CL and 80 Py+CL/20 CL), each with a diblock or a random structure, were used to prepare nanoparticulate complexes with DNA. Average size and surface charge of the complexes and extent of the complexation were measured. The DNA condensation by the copolymers was analysed by a gel retardation assay. Cytotoxicity and transfection efficiency of the copolymers were also evaluated in HeLa cells and compared with polyethylenimine 50 kDa. The size of the polyplexes was approximately 200 nm. The zeta potential first increased with the copolymer/DNA charge ratio and became positive for charge ratios in the 2-4 range depending on the type of copolymer. DNA was completely condensed within the nanoparticles and the degree of interaction was very high. Cytotoxicity and transfection efficiency were found to be comparable to polyethylenimine 50 kDa. The experimental results suggest that the novel copolymers can be used as novel gene delivery vectors. PMID:17258343

Vroman, Benoît; Mazza, Michaël; Fernandez, Manuela R; Jérôme, Robert; Préat, Véronique

2007-03-12

282

Clostridium difficile and the microbiota.  

PubMed

Clostridium difficile infection (CDI) is the leading health care-associated illness. Both human and animal models have demonstrated the importance of the gut microbiota's capability of providing colonization resistance against C. difficile. Risk factors for disease development include antibiotic use, which disrupts the gut microbiota, leading to the loss of colonization resistance and subsequent CDI. Identification of the specific microbes capable of restoring this function remains elusive. Future studies directed at how microbial communities influence the metabolic environment may help elucidate the role of the microbiota in disease development. These findings will improve current biotherapeutics for patients with CDI, particularly those with recurrent disease. PMID:25036699

Seekatz, Anna M; Young, Vincent B

2014-10-01

283

Clostridium difficile infection: nursing considerations.  

PubMed

Clostridium difficile is a bacterium which commonly causes diarrhoea in inpatients. C. difficile affects hospitalised patients worldwide and can pose a significant risk to patients. This article explores the transmission and risk factors for C. difficile infection (CDI). There are many aspects to the prevention and control of CDI: appropriate antibiotic use, early instigation and maintenance of prevention and control strategies, and high standards of environmental cleanliness, education, and surveillance. This article discusses the role of the nurse in each of these prevention and control activities. PMID:25052676

Mitchell, Brett G; Russo, Phillip L; Race, Paul

2014-07-29

284

Differential amylosaccharide metabolism of Clostridium thermosulfurogenes and Clostridium thermohydrosulfuricum.  

PubMed Central

Clostridium thermosulfurogenes displayed faster growth on either glucose, maltose, or starch than Clostridium thermohydrosulfuricum. Both species grew faster on glucose than on starch or maltose. The fermentation end product ratios were altered based on higher ethanol and lactate yields on starch than on glucose. In C. thermohydrosulfuricum, glucoamylase, pullulanase, and maltase were mainly responsible for conversion of starch and maltose into glucose, which was accumulated by a putative glucose permease. In C. thermosulfurogenes, beta-amylase was primarily responsible for degradation of starch to maltose, which was accumulated by a putative maltose permease and then hydrolyzed by glucoamylase. Regardless of the growth substrate, the rates of glucose, maltose, and starch transformation were higher in C. thermosulfurogenes than in C. thermohydrosulfuricum. Both species had a functional Embden-Meyerhof glycolytic pathway and displayed the following catabolic activities: ferredoxin-linked pyruvate dehydrogenase, acetate kinase, NAD(P)-ethanol dehydrogenase, NAD(P)-ferredoxin oxidoreductase, hydrogenase, and fructose-1,6-diphosphate-activated lactate dehydrogenase. Ferredoxin-NAD reductase activity was higher in C. thermohydrosulfuricum than NADH-ferredoxin oxidase activity, but the former activity was not detectable in C. thermosulfurogenes. Both NAD- and NADP-linked ethanol dehydrogenases were unidirectional in C. thermosulfurogenes but reversible in C. thermohydrosulfuricum. The ratio of hydrogen-producing hydrogenase to hydrogen-consuming hydrogenase was higher in C. thermosulfurogenes. Two biochemical models are proposed to explain the differential saccharide metabolism on the basis of species enzyme differences in relation to specific growth substrates. PMID:3934139

Hyun, H H; Shen, G J; Zeikus, J G

1985-01-01

285

Binary Bacterial Toxins: Biochemistry, Biology, and Applications of Common Clostridium and Bacillus Proteins  

PubMed Central

Certain pathogenic species of Bacillus and Clostridium have developed unique methods for intoxicating cells that employ the classic enzymatic “A-B” paradigm for protein toxins. The binary toxins produced by B. anthracis, B. cereus, C. botulinum, C. difficile, C. perfringens, and C. spiroforme consist of components not physically associated in solution that are linked to various diseases in humans, animals, or insects. The “B” components are synthesized as precursors that are subsequently activated by serine-type proteases on the targeted cell surface and/or in solution. Following release of a 20-kDa N-terminal peptide, the activated “B” components form homoheptameric rings that subsequently dock with an “A” component(s) on the cell surface. By following an acidified endosomal route and translocation into the cytosol, “A” molecules disable a cell (and host organism) via disruption of the actin cytoskeleton, increasing intracellular levels of cyclic AMP, or inactivation of signaling pathways linked to mitogen-activated protein kinase kinases. Recently, B. anthracis has gleaned much notoriety as a biowarfare/bioterrorism agent, and of primary interest has been the edema and lethal toxins, their role in anthrax, as well as the development of efficacious vaccines and therapeutics targeting these virulence factors and ultimately B. anthracis. This review comprehensively surveys the literature and discusses the similarities, as well as distinct differences, between each Clostridium and Bacillus binary toxin in terms of their biochemistry, biology, genetics, structure, and applications in science and medicine. The information may foster future studies that aid novel vaccine and drug development, as well as a better understanding of a conserved intoxication process utilized by various gram-positive, spore-forming bacteria. PMID:15353562

Barth, Holger; Aktories, Klaus; Popoff, Michel R.; Stiles, Bradley G.

2004-01-01

286

[Morphological changes in human embryonic lung fibroblasts caused by cytotoxins of various Clostridium species].  

PubMed

A total of 243 strains of 35 Clostridium species were tested for cytotoxin production in cooked meat medium or liver broth within 48-72 h at 37 degrees C, using human embryonal lung fibroblasts in tissue-culture as indicator cells. Cytotoxin could be detected in the culture-filtrates of all toxigenic strains of C. chauvoei, C. difficile, C. histolyticum, C. novyi types A and B, C. septicum and C. tetani, but not in the atoxigenic ones. The cytotoxin of C. novyi correlated with alpha-toxin in the culture filtrate. All strains of C. perfringens and C. novyi D tested were not cytotoxic for lung fibroblasts despite their pathogenicity for guinea-pigs. Further cytotoxigenic strains were found among C. hastiforme, C. limosum, C. oceanicum, C. putrificum, C. ramosum, C. sordellii, C. sporogenes, and C. subterminale. The morphological changes in lung fibroblasts caused by the culture filtrates were characteristic and species-specific and corresponded with pathogenicity for guinea-pigs and/or mice. No cytotoxin was produced by C. absonum, C. barati, C. bifermentans, C. botulinum (atoxic), C. butyricum, C. cadaveris, C. carnis, C. clostridioforme, C. cochlearium, C. glycolicum, C. innocuum, C. malenominatum, C. mangenotii, C. paraputrificum, C. putrefaciens, C. rectum, C. tertium, and C. tyrobutyricum. PMID:3376617

Schallehn, G; Wolff, M H

1988-01-01

287

Clostridium acetobutylicum protoplast formation and regeneration  

SciTech Connect

Clostridium acetobutylicum is already used for the industrial production of acetone and butanol from molasses. Further advantages include its ability to utilize pentose sugars and produce a carboxymethyl cellulase and a cellobiase. The development of genetic transfer systems enabling the use of genetic manipulation techniques would greatly enhance the potential of the fermentation system. Techniques and media for the production and regeneration of stable Clostridium acetobutylicum protoplasts are described. (Refs. 12).

Allcock, E.R.; Reid, S.J.; Jones, D.T.; Woods, D.R.

1982-03-01

288

Clostridium difficile-associated diarrhoea.  

PubMed Central

At our hospital, the number of cases of Clostridium difficile-associated diarrhoea increased from 29 in 1993 to 210 in 1995. The case notes of 110 patients with C difficile-associated diarrhoea during the first 6 months of 1995 were analysed retrospectively. The majority of the patients (106) had received antibiotics before the onset of diarrhoea; 46 had received three or more different antibiotics and 28 had received metronidazole. In 19 patients, the first stool sample after the onset of diarrhoea was negative for C difficile cytotoxin, with a mean delay of 8.2 days before a positive stool sample. We conclude that C difficile-associated diarrhoea was associated with the usage of multiple antibiotics, and that metronidazole did not protect against colonisation by C difficile. We also recommend that more than one stool sample should be tested for the C difficile cytotoxin. PMID:10197216

Wight, N.; Curtis, H.; Hyde, J.; Borriello, S. P.; Mahida, Y. R.

1998-01-01

289

Clostridium difficile colitis: a review.  

PubMed

Clostridium difficile has become an increasingly important nosocomial pathogen and is one of the most common causes of hospital-acquired diarrhea. The incidence of C difficile infection (CDI) is increasing worldwide. Overuse of antibiotics is felt to be a major contributing factor leading to the increased incidence of CDI. The clinical manifestations of CDI vary from a mild form of the disease to fulminant diarrhea, leading to significant patient morbidity and mortality. The increasing incidence of CDI has a major impact on increasing health care costs. This article will summarize the epidemiology, pathogenesis, clinical manifestations, laboratory diagnosis, and treatment options for CDI, as well as infection-control measures for the prevention of CDI. PMID:22406889

Moudgal, Varsha; Sobel, Jack D

2012-02-01

290

[Infections caused by Clostridium difficile].  

PubMed

The epidemiology of Clostridium difficile infections (CDIs) has dramatically changed over the last decade in both North America and Europe, and it has become more frequent, more severe, more refractory to standard therapy, and more likely to relapse. These changes have been associated with the emergence of a "hypervirulent" strain known as BI/NAP1/027 which has become endemic in some areas, although, other hypervirulent genotypes (e.g. PCR ribotype 078) have also been described. To reduce the incidence of CDIs, the diagnostic guidelines on diagnosis and treatment methods have been recently updated. The aim of this review is to highlight the recent epidemiological data on CDIs and to provide an overview of the pathogenicity of the infection, diagnostic approaches, old and new treatment options, and current knowledge of infection control measures. PMID:23411363

Rodríguez-Pardo, Dolors; Mirelis, Beatriz; Navarro, Ferran

2013-04-01

291

Biofilm formation by Clostridium difficile  

PubMed Central

Clostridium difficile infection (CDI) is a major healthcare-associated disease worldwide. Recurring infections and increasing antibiotic resistance have complicated treatment of CDI. While C. difficile spores are important for transmission and persistence of CDI, other factors such as gut colonization and formation of bacterial communities in the gut may also contribute to pathogenesis and persistence, but have not been well investigated. Recently, we reported that important clinical C. difficile strains are able to form composite biofilms in vitro. C. difficile biofilm formation is a complex process, modulated by several different factors, including cell surface components and regulators. We also reported that bacteria within biofilms are more resistant to high concentrations of vancomycin, the antibiotic of choice for treatment of CDI. Here we summarize our recent findings and discuss the implications of biofilm formation by this anaerobic gut pathogen in disease pathogenesis and treatment. PMID:23892245

Dapa, Tanja; Unnikrishnan, Meera

2013-01-01

292

The Challenge of Observing the Recent Eclipse of Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

This author participated in the 'International Epsilon Aurigae Campaign' in 2009. A total of 100 V-band observations were made in Holtsville, New York for the 2009-2011 eclipse of Epsilon Aurigae. A lightcurve has been plotted using data from these observations, which cover the phase before, during and after the eclipse. The lightcurve shows precise timing during the first, second, third and fourth contacts and possibly mid-eclipse brightening. The magnitude and the duration of the eclipse in photometric V band are discussed. This poster represents the work by Frank J Melillo and the observations were close enough to generate the true shape of the lightcurve.

Melillo, Frank J.

2013-07-01

293

Assessment of epsilon-equations for wall shear flows with DNS database. I - The case of k-epsilon two-equation modeling  

NASA Astrophysics Data System (ADS)

Using direct numerical simulation (DNS) data base for wall turbulence, we performed critical assessment of representative dissipation-rate equations (i.e., epsilon of average-epsilon equations) for k-epsilon turbulence models and proposed a new dissipation-rate equation. The DNS data of mean velocity and turbulent kinetic energy are used as the known exact quantities for solving the epsilon or average-epsilon equation. Thus, the obtained values of epsilon are the true solutions with no contaminants. The assessment indicates that, except for one recent model, the performance in predicting the exact epsilon profiles is poor, irrespective of the model type. The proposed model constructed on the basis of the proposal of Nagano and Hishida (1987) provides a good performance, though the model formulation is very simple.

Nagano, Yasutaka; Youssef, Mahmound S.; Shimada, Masaya

1993-06-01

294

Interactions of rumen chitinolytic bacterium, Clostridium tertium with anaerobic fungi  

E-print Network

Interactions of rumen chitinolytic bacterium, Clostridium tertium with anaerobic fungi B Hodrova J spore forming, Gram- positive rods. The isolate ChK5 was identified as Clostridium tertium and further

Paris-Sud XI, Université de

295

Interactions of High-Affinity Cationic Blockers with the Translocation Pores of B. anthracis, C. botulinum, and C. perfringens Binary Toxins  

PubMed Central

Cationic ?-cyclodextrin derivatives were recently introduced as highly effective, potentially universal blockers of three binary bacterial toxins: anthrax toxin of Bacillus anthracis, C2 toxin of Clostridium botulinum, and iota toxin of Clostridium perfringens. The binary toxins are made of two separate components: the enzymatic A component, which acts on certain intracellular targets, and the binding/translocation B component, which forms oligomeric channels in the target cell membrane. Here we studied the voltage and salt dependence of the rate constants of binding and dissociation reactions of two structurally different ?-cyclodextrins (AmPr?CD and AMBnT?CD) in the PA63, C2IIa, and Ib channels (B components of anthrax, C2, and iota toxins, respectively). With all three channels, the blocker carrying extra hydrophobic aromatic groups on the thio-alkyl linkers of positively charged amino groups, AMBnT?CD, demonstrated significantly stronger binding compared with AmPr?CD. This effect is seen as an increased residence time of the blocker in the channels, whereas the time between blockages characterizing the binding reaction on-rate stays practically unchanged. Surprisingly, the voltage sensitivity, expressed as a slope of the logarithm of the blocker residence time as a function of voltage, turned out to be practically the same for all six cases studied, suggesting structural similarities among the three channels. Also, the more-effective AMBnT?CD blocker shows weaker salt dependence of the binding and dissociation rate constants compared with AmPr?CD. By estimating the relative contributions of the applied transmembrane field, long-range Coulomb, and salt-concentration-independent, short-range forces, we found that the latter represent the leading interaction, which accounts for the high efficiency of blockage. In a search for the putative groups in the channel lumen that are responsible for the short-range forces, we performed measurements with the F427A mutant of PA63, which lacks the functionally important phenylalanine clamp. We found that the on-rates of the blockage were virtually conserved, but the residence times and, correspondingly, the binding constants dropped by more than an order of magnitude, which also reduced the difference between the efficiencies of the two blockers. PMID:22995493

Bezrukov, Sergey M.; Liu, Xian; Karginov, Vladimir A.; Wein, Alexander N.; Leppla, Stephen H.; Popoff, Michel R.; Barth, Holger; Nestorovich, Ekaterina M.

2012-01-01

296

Clostridium difficile infection in patients with inflammatory bowel disease  

PubMed Central

Clostridium difficile is a bacterium widely distributed in the human environment. In the last decade the incidence and severity of Clostridium difficile infection has grown, particularly in Europe and North America, making it one of the more common nosocomial infections. A group particularly susceptible to Clostridium difficile infection are patients with inflammatory bowel disease, especially those with involvement of the colon. This paper presents relevant data on Clostridium difficile infections in inflammatory bowel disease patients, including epidemiology, pathogenesis, diagnosis and treatment. PMID:25097707

Biesiada, Grazyna; Perucki, William; Mach, Tomasz

2014-01-01

297

Density Versions of Plunnecke Inequality Epsilon-Delta Approach  

E-print Network

Density Versions of Pl¨unnecke Inequality ­ Epsilon-Delta Approach Renling Jin Abstract We discuss whether Pl¨unnecke's inequality for Shnirel'man density with respect to Shnirel'man basis can be generalized to other densities with respect to other concepts of basis. We show behavioral disparities between

Jin, Renling

298

Density Versions of Plunnecke Inequality Epsilon-Delta Approach  

E-print Network

Density Versions of Pl¨unnecke Inequality ­ Epsilon-Delta Approach Renling Jin Abstract We discuss whether Pl¨unnecke's inequality for Shnirel'man density with respect to Shnirel'man basis can be generalized to other densities with respect to other con- cepts of basis. We show behavioral disparities

Jin, Renling

299

EPSILON SURGERY THEORY STEVE FERRY AND ERIK KJR PEDERSEN  

E-print Network

EPSILON SURGERY THEORY STEVE FERRY AND ERIK KJ�R PEDERSEN Contents 1. Introduction 2 2. Algebraic preliminaries 4 3. Bounded Poincar´e complexes 8 4. Spivak normal fibre space 9 5. Surgery below the middle. The surgery groups 22 10. Ranicki-Rothenberg sequences, and L- 26 11. The surgery exact sequence 29 12

Pedersen, Erik Kjær

300

An improved k-epsilon model for near wall turbulence  

NASA Technical Reports Server (NTRS)

An improved k-epsilon model for low Reynolds number turbulence near a wall is presented. In the first part of this work, the near-wall asymptotic behavior of the eddy viscosity and the pressure transport term in the turbulent kinetic energy equation are analyzed. Based on these analyses, a modified eddy viscosity model with the correct near-wall behavior is suggested, and a model for the pressure transport term in the k-equation is proposed. In addition, a modeled dissipation rate equation is reformulated, and a boundary condition for the dissipation rate is suggested. In the second part of the work, one of the deficiencies of the existing k-epsilon models, namely, the wall distance dependency of the equations and the damping functions, is examined. An improved model that does not depend on any wall distance is introduced. Fully developed turbulent channel flows and turbulent boundary layers over a flat plate are studied as validations for the proposed new models. Numerical results obtained from the present and other previous k-epsilon models are compared with data from direct numerical simulation. The results show that the present k-epsilon model, with added robustness, performs as well as or better than other existing models in predicting the behavior of near-wall turbulence.

Shih, T. H.; Hsu, Andrew T.

1991-01-01

301

Infinite Bottles of Beer Mathematical Concepts with Epsilon Pain  

E-print Network

1 Infinite Bottles of Beer Mathematical Concepts with Epsilon Pain Or: A cantorial approach this: A hundred bottles of beer on the wall, a hundred bottles of beer; If one of those bottles should happen to fall, 99 bottles of beer on the wall. 99 bottles of beer on the wall, 99 bottles of beer

Indiana University

302

Interaction Between Salmonella Phage Epsilon 15 and an Isolated Receptor Substance.  

National Technical Information Service (NTIS)

The report deals with some preliminary results on the interactions between phage epsilon 15 and cellular lipopolysaccharides (=LPS) carrying O-antigenic determinants. Phage strains employed were Salmonella phages epsilon 15 and g341 (12, 10, 7, 4). Bacter...

K. Takeda, H. Uetake

1968-01-01

303

[Clostridium-difficile-associated infections].  

PubMed

C. difficile is a spore-forming anaerobic enteropathogen. This bacillus is responsible for virtually all cases of pseudomembranous colitis and for 15 to 25% of cases of antibiotic-associated diarrhoea. Clostridium difficile associated-infections (CDI) have a wide range of clinical features which vary from mild uncomplicated diarrhoea to severe debilitating disease, paralytic ileus, toxic megacolon, or even perforation and sometimes death. Risk factors for CDI include age > 65 years, previous hospitalization and recent antibiotic therapy. Main virulence factors for this pathogen are toxins A and B. A third toxin, the binary toxin, has been found in up to 10% of strains from infected patients. For some years, a new hypervirulent strain has emerged. This epidemic strain belongs to PCR-ribotype 027 and is responsible for outbreaks with increased mortality and severity in North America and Europe. The most effective antibiotics for treatment are oral metronidazole and vancomycin. Control of CDI needs to prevent the emergence of CDI by minimizing the number of patients exposed to antimicrobials and to limit cross transmission. PMID:20188046

Eckert, Catherine; Barbut, Frédéric

2010-02-01

304

Clostridium tertium septicemia in patients with neutropenia.  

PubMed

Eighteen adult patients with hematologic malignancy developed bacteremia due to Clostridium tertium while neutropenic. Fifteen had accompanying abdominal pain, colonic bleeding, or diarrhea, and three had perianal cellulitis. Fourteen recovered with antibiotic therapy alone; no patient was treated by surgery. C. tertium is an unusual Clostridium because it is resistant to many beta-lactam antibiotics and to metronidazole but is susceptible to vancomycin, trimethoprim-sulfamethoxazole, and ciprofloxacin. It is possible that use of third-generation cephalosporins (cefotaxime, ceftizoxime, ceftazidime) for treating febrile episodes in the absence of any selective intestinal decontamination with trimethoprim-sulfamethoxazole or ciprofloxacin may have resulted in selection for C. tertium in our patients. PMID:3198941

Speirs, G; Warren, R E; Rampling, A

1988-12-01

305

Covariance Estimation for Distributions with 2+\\epsilon Moments  

E-print Network

We study the minimal sample size N=N(n) that suffices to estimate the covariance matrix of an n-dimensional distribution by the sample covariance matrix in the operator norm, and with an arbitrary fixed accuracy. We establish the optimal bound N = O(n) for every distribution whose k-dimensional marginals have uniformly bounded 2+\\epsilon moments outside the sphere of radius O(\\sqrt{k}). In the specific case of log-concave distributions, this result provides an alternative approach to the Kannan-Lovasz-Simonovits problem, which was recently solved by Adamczak, Litvak, Pajor and Tomczak-Jaegermann. Moreover, a lower estimate on the covariance matrix holds under a weaker assumption -- uniformly bounded 2+\\epsilon moments of one-dimensional marginals. Our argument proceeds by randomizing the spectral sparsification technique of Batson, Spielman and Srivastava. The spectral edges of the sample covariance matrix are controlled via the Stieltjes transform evaluated at carefully chosen random points.

Srivastava, Nikhil

2011-01-01

306

A Study of Epsilon Canis Majoris (B2II)  

NASA Astrophysics Data System (ADS)

We propose to obtain high quality LETG observations of the B giant Epsilon Canis Majoris (B2II). These observations will be analyzed together with available optical, IUE, EUVE, and XMM data. Epsilon Canis Majoris is one of only two early-type stars detected in the EUV (lambda < 900Ang) with the NASA Extreme Ultraviolet Explorer (EUVE) satellite, and is the main photoionization source within the solar neighborhood. With high quality Chandra X-ray spectra we will have a complete spectrum, from X-ray to IR wavelengths, that can be analyzed self- consistently. This will allow tight constraints to be placed on the star, its wind, and the X-ray emitting plasma.

Hillier, John

2005-09-01

307

EISCAT observations during MAC/SINE and MAC/Epsilon  

NASA Technical Reports Server (NTRS)

The EISCAT incoherent scatter radar facility in Tromsoe, Norway was operated during the MAC/SINE campaign for 78 hours in the period 10 June to 17 July 1987, and during the MAC/Epsilon campaign for 90 hours in the period 15 October to 5 November 1987. The VHF (224 MHz) radar operations during MAC/SINE yielded most interesting observations of strong coherent echoes from the mesopause region. Characteristic data of these polar mesospheric summer echoes are presented. The UHF (933 MHz) radar operations during MAC/Epsilon were done with 18 deg off zenith beam and allows the deduction of meridonal and horizontal wind components as well as radial velocity spectra in addition to the usual electron density profiles in the D and lower E regions. Some results from the VHF and UHF radars indicating the presence of gravity waves are examined.

Roettger, J.; Hoppe, U.-P.; Hall, C.

1989-01-01

308

A kappa-epsilon calculation of transitional boundary layers  

NASA Technical Reports Server (NTRS)

A recently proposed kappa-epsilon model for low Reynolds number turbulent flows was modified by introducing a new damping function f(sub mu). The modified model is used to calculate the transitional boundary layer over a flat plate with different freestream turbulence levels. It is found that the model could mimic the transitional flow. However, the predicted transition is found to be sensitive to the initial conditions.

Yang, Z.; Shih, T. H.

1992-01-01

309

Occultation of Epsilon Geminorum by Mars - Evidence for atmospheric tides  

NASA Technical Reports Server (NTRS)

Epsilon Geminorum occultation data obtained on April 8, 1976, with the aid of a 91-cm telescope aboard the NASA Kuiper Airborne Observatory have provided a basis for the determination of temperature, pressure, and number density profiles of the Martian atmosphere. The results concerning the temperature profiles are compared with those of Viking 1 reported by Nier et al. (1976) and with theoretical predictions of thermally driven tides in the Martian atmosphere made by Zurek (1976).

Elliot, J. L.; French, R. G.; Dunham, E.; Gierasch, P. J.; Veverka, J.; Church, C.; Sagan, C.

1977-01-01

310

Atypical glycolysis in Clostridium thermocellum.  

PubMed

Cofactor specificities of glycolytic enzymes in Clostridium thermocellum were studied with cellobiose-grown cells from batch cultures. Intracellular glucose was phosphorylated by glucokinase using GTP rather than ATP. Although phosphofructokinase typically uses ATP as a phosphoryl donor, we found only pyrophosphate (PPi)-linked activity. Phosphoglycerate kinase used both GDP and ADP as phosphoryl acceptors. In agreement with the absence of a pyruvate kinase sequence in the C. thermocellum genome, no activity of this enzyme could be detected. Also, the annotated pyruvate phosphate dikinase (ppdk) is not crucial for the generation of pyruvate from phosphoenolpyruvate (PEP), as deletion of the ppdk gene did not substantially change cellobiose fermentation. Instead pyruvate formation is likely to proceed via a malate shunt with GDP-linked PEP carboxykinase, NADH-linked malate dehydrogenase, and NADP-linked malic enzyme. High activities of these enzymes were detected in extracts of cellobiose-grown cells. Our results thus show that GTP is consumed while both GTP and ATP are produced in glycolysis of C. thermocellum. The requirement for PPi in this pathway can be satisfied only to a small extent by biosynthetic reactions, in contrast to what is generally assumed for a PPi-dependent glycolysis in anaerobic heterotrophs. Metabolic network analysis showed that most of the required PPi must be generated via ATP or GTP hydrolysis exclusive of that which happens during biosynthesis. Experimental proof for the necessity of an alternative mechanism of PPi generation was obtained by studying the glycolysis in washed-cell suspensions in which biosynthesis was absent. Under these conditions, cells still fermented cellobiose to ethanol. PMID:23435896

Zhou, Jilai; Olson, Daniel G; Argyros, D Aaron; Deng, Yu; van Gulik, Walter M; van Dijken, Johannes P; Lynd, Lee R

2013-05-01

311

Atypical Glycolysis in Clostridium thermocellum  

PubMed Central

Cofactor specificities of glycolytic enzymes in Clostridium thermocellum were studied with cellobiose-grown cells from batch cultures. Intracellular glucose was phosphorylated by glucokinase using GTP rather than ATP. Although phosphofructokinase typically uses ATP as a phosphoryl donor, we found only pyrophosphate (PPi)-linked activity. Phosphoglycerate kinase used both GDP and ADP as phosphoryl acceptors. In agreement with the absence of a pyruvate kinase sequence in the C. thermocellum genome, no activity of this enzyme could be detected. Also, the annotated pyruvate phosphate dikinase (ppdk) is not crucial for the generation of pyruvate from phosphoenolpyruvate (PEP), as deletion of the ppdk gene did not substantially change cellobiose fermentation. Instead pyruvate formation is likely to proceed via a malate shunt with GDP-linked PEP carboxykinase, NADH-linked malate dehydrogenase, and NADP-linked malic enzyme. High activities of these enzymes were detected in extracts of cellobiose-grown cells. Our results thus show that GTP is consumed while both GTP and ATP are produced in glycolysis of C. thermocellum. The requirement for PPi in this pathway can be satisfied only to a small extent by biosynthetic reactions, in contrast to what is generally assumed for a PPi-dependent glycolysis in anaerobic heterotrophs. Metabolic network analysis showed that most of the required PPi must be generated via ATP or GTP hydrolysis exclusive of that which happens during biosynthesis. Experimental proof for the necessity of an alternative mechanism of PPi generation was obtained by studying the glycolysis in washed-cell suspensions in which biosynthesis was absent. Under these conditions, cells still fermented cellobiose to ethanol. PMID:23435896

Zhou, Jilai; Olson, Daniel G.; Argyros, D. Aaron; Deng, Yu; van Gulik, Walter M.; van Dijken, Johannes P.

2013-01-01

312

Magnetic Activity Cycles in the Exoplanet Host Star epsilon Eridani  

NASA Astrophysics Data System (ADS)

The active K2 dwarf epsilon Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in epsilon Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 ± 0.03 years and 12.7 ± 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called "active" and "inactive" sequences as proposed by Böhm-Vitense. Finally, based on the observed properties of epsilon Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

Metcalfe, T. S.; Buccino, A. P.; Brown, B. P.; Mathur, S.; Soderblom, D. R.; Henry, T. J.; Mauas, P. J. D.; Petrucci, R.; Hall, J. C.; Basu, S.

2013-02-01

313

In vitro synergy studies with Clostridium difficile.  

PubMed Central

Agar dilution anaerobic susceptibility studies using rifampin, vancomycin, metronidazole, and bacitracin individually and in combination were performed with Clostridium difficile. Fifty-five strains of C. difficile were studied. Eighty-five percent of strains tested (29 of 34) were synergistically inhibited by the combination of bacitracin and rifampin (fractional inhibitory concentration, less than or equal to 0.50). PMID:2039211

Bacon, A E; McGrath, S; Fekety, R; Holloway, W J

1991-01-01

314

Human Infection Caused by Clostridium hathewayi  

PubMed Central

We describe a 27-year-old man with acute cholecystitis, hepatic abscess, and bacteremia caused by Clostridium hathewayi, a newly described gram-negative, endospore-forming, rod-shaped bacterium. This report is the first of human infection caused by this microorganism. PMID:15550205

Zhang, Kunyan

2004-01-01

315

Neutropenic enterocolitis associated with Clostridium tertium  

Microsoft Academic Search

A 15 year old boy being treated for relapsed acute lymphoblastic leukaemia developed severe diarrhoea and abdominal pain which worsened despite empirical antibiotic treatment. A right hemicolectomy was performed. The caecum and ascending colon showed changes typical of neutropenic enterocolitis. Clostridium tertium was isolated from faeces, blood cultures, and from the resected gut wall, with no evidence of other organisms

N Coleman; G Speirs; J Khan; V Broadbent; D G Wight; R E Warren

1993-01-01

316

Clostridium difficile in children: colonisation and disease.  

PubMed

Clostridium difficile is the commonest cause of hospital acquired diarrhoea in adults and is associated with significant mortality and morbidity. The clinical significance of C. difficile in children, however, is less certain. In this article we discuss colonisation and infection and describe C. difficile in childhood in terms of risk factors, epidemiology and management. PMID:21664931

Enoch, David A; Butler, Matthew J; Pai, Sumita; Aliyu, Sani H; Karas, J Andreas

2011-08-01

317

Clostridium difficile infection and pseudomembranous colitis  

Microsoft Academic Search

Clostridium difficile causes a spectrum of diseases ranging from diarrhoea to pseudomembranous colitis, primarily in the hospitalized elderly, although community-acquired infection is probably under-documented. Host factors are increasingly recognized as critical determinants of disease expression. Exposure to antibiotics, particularly those adversely affecting anaerobic gut flora, appears to create a niche which is exploited by C. difficile. Several retrospective and intervention

Mark H Wilcox

2003-01-01

318

Clostridium difficile infection and pseudomembranous colitis  

Microsoft Academic Search

Clostridium difficile causes a spectrum of diseases ranging from diarrhoea to pseudomembranous colitis, primarily in the hospitalized elderly, although community-acquired infection is probably under-documented. Host factors are increasingly recognized as critical determinants of disease expression. Exposure to antibiotics, particularly those adversely affecting anaerobic gut flora, appears to create a niche which is exploited by C. difficile. Several retrospective and intervention

Mark H. Wilcox

319

Clostridium botulinum in Cattle and Dairy Products  

Microsoft Academic Search

The use of plastic-wrapped and nonacidified silage as cattle feed has led to an increasing number of botulism outbreaks due to Clostridium botulinum Groups I-III in dairy cattle. The involvement of Groups I and II organisms in cattle botulism has raised concern of human botulism risk associated with the consumption of dairy products. Multiplication of C. botulinum in silage and

Miia Lindström; Jan Myllykoski; Seppo Sivelä; Hannu Korkeala

2010-01-01

320

Clostridium difficile and C. difficile Toxin Testing  

MedlinePLUS

... the Adult Patient with Fever of Unknown Origin. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20031201/2223.html through http://www.aafp.org . Clostridium difficile Toxins and Culture. ARUP's Guide to Clinical Laboratory Testing [On-line ...

321

Epidemiology of Clostridium difficile in Infants  

Microsoft Academic Search

The epidemiology of Clostridium difficile was studied prospectively in 451 newborn infants by daily screening of fecal samples. Colonization rates in three postnatal wards ranged from 2% to 52%. Many colonizations were sporadic, but on two wards there was evidence of clustering. On one of these occasions prospective environmental sampling yielded C. difficile organisms from a potential common source. Mothers

H. E. Larson; F. E. Barclay; P. Honour; I. D. Hill

1982-01-01

322

Coculture Production of Butanol by Clostridium Bacteria  

NASA Technical Reports Server (NTRS)

Production of butanol by anaerobic fermentation of sugars enhanced by use of two Clostridium species, one of which feeds on metabolic product of other. Renewed interest in fermentation process for making butanol stimulated by potential use of butanol as surfactant in enhanced oil recovery. Butanol also used as fuel or as chemical feedstock and currently produced synthetically from petroleum.

Bergstrom, S. L.; Foutch, G. L.

1985-01-01

323

International typing study of Clostridium difficile.  

PubMed

We report the results of an international Clostridium difficile typing study to cross reference strain designations for seven typing methodologies and facilitate inter-laboratory communication. Four genotypic and three phenotypic methods were used to type 100 isolates and compare the results to 39 PCR ribotypes identified among the collection. PMID:24768986

Manzo, Carl E; Merrigan, Michelle M; Johnson, Stuart; Gerding, Dale N; Riley, Thomas V; Silva, Joseph; Brazier, Jon S

2014-08-01

324

Antibiotic-Associated Diarrhea Caused by Clostridium difficile (Beyond the Basics)  

MedlinePLUS

... manifestations and diagnosis Clostridium difficile in adults: Epidemiology, microbiology, and pathophysiology Clostridium difficile in adults: Treatment Clostridium difficile infection: Prevention and control Fecal microbiota transplantation in the treatment of recurrent ...

325

An Attempt to Derive the epsilon Equation from a Two-Point Closure  

NASA Technical Reports Server (NTRS)

The goal of this paper is to derive the equation for the turbulence dissipation rate epsilon for a shear-driven flow. In 1961, Davydov used a one-point closure model to derive the epsilon equation from first principles but the final result contained undetermined terms and thus lacked predictive power. Both in 1987 and in 2001, attempts were made to derive the epsilon equation from first principles using a two-point closure, but their methods relied on a phenomenological assumption. The standard practice has thus been to employ a heuristic form of the equation that contains three empirical ingredients: two constants, c(sub 1 epsilon), and c(sub 2 epsilon), and a diffusion term D(sub epsilon) In this work, a two-point closure is employed, yielding the following results: 1) the empirical constants get replaced by c(sub 1), c(sub 2), which are now functions of Kappa and epsilon; 2) c(sub 1) and c(sub 2) are not independent because a general relation between the two that are valid for any Kappa and epsilon are derived; 3) c(sub 1), c(sub 2) become constant with values close to the empirical values c(sub 1 epsilon), c(sub epsilon 2), (i.e., homogenous flows); and 4) the empirical form of the diffusion term D(sub epsilon) is no longer needed because it gets substituted by the Kappa-epsilon dependence of c(sub 1), c(sub 2), which plays the role of the diffusion, together with the diffusion of the turbulent kinetic energy D(sub Kappa), which now enters the new equation (i.e., inhomogeneous flows). Thus, the three empirical ingredients c(sub 1 epsilon), c(sub epsilon 2), D (sub epsilon)are replaced by a single function c(sub 1)(Kappa, epsilon ) or c(sub 2)(Kappa, epsilon ), plus a D(sub Kappa)term. Three tests of the new equation for epsilon are presented: one concerning channel flow and two concerning the shear-driven planetary boundary layer (PBL).

Canuto, V. M.; Cheng, Y.; Howard, A. M.

2010-01-01

326

A complicated quasicrystal approximant epsilon16 predicted by the strong-reflections approach.  

PubMed

The structure of a complicated quasicrystal approximant epsilon(16) was predicted from a known and related quasicrystal approximant epsilon(6) by the strong-reflections approach. Electron-diffraction studies show that in reciprocal space, the positions of the strongest reflections and their intensity distributions are similar for both approximants. By applying the strong-reflections approach, the structure factors of epsilon(16) were deduced from those of the known epsilon(6) structure. Owing to the different space groups of the two structures, a shift of the phase origin had to be applied in order to obtain the phases of epsilon(16). An electron-density map of epsilon(16) was calculated by inverse Fourier transformation of the structure factors of the 256 strongest reflections. Similar to that of epsilon(6), the predicted structure of epsilon(16) contains eight layers in each unit cell, stacked along the b axis. Along the b axis, epsilon(16) is built by banana-shaped tiles and pentagonal tiles; this structure is confirmed by high-resolution transmission electron microscopy (HRTEM). The simulated precession electron-diffraction (PED) patterns from the structure model are in good agreement with the experimental ones. Epsilon(16) with 153 unique atoms in the unit cell is the most complicated approximant structure ever solved or predicted. PMID:20101079

Li, Mingrun; Sun, Junliang; Oleynikov, Peter; Hovmöller, Sven; Zou, Xiaodong; Grushko, Benjamin

2010-02-01

327

Epsilon Canis Majoris and the ionization of the local cloud  

NASA Technical Reports Server (NTRS)

The Lyman continuum radiation from the brightest extreme ultraviolet (EUV) source, the B2 II star epsilon Canis Majoris (Adara), is so intense that it dominates the local stellar EUV radiation field at wavelengths longer than 450 A and therefore sets a lower limit to the ionization of hydrogen in the Local Cloud. Using the EUV (70-730 A) spectrum of epsilon CMa taken with the Extreme Ultraviolet Explorer Satellite (EUVE) and simple models that extrapolate this spectrum to the Lyman edge at 912 A, we have determined the local interstellar hydrogen photionizatin parameter Gamma solely from epsilon CMa to be 1.1 x 10(exp -15)/s. This fiugre is a factor of 7 greater than previous estimates of Gamma calculated for all nearby stars combined (Bruhweiler & Cheng 1988). Using measured values of the density and temperature of neutral interstellar hydrogen gas in the Local Cloud, we derive a particle density of ionized hydrogen n(H(+)) and electrons n(sub e) of 0.015-0.019/cu cm assuming ionization equilibrium and a helium ionization fraction of less than 20%. These values correspond to a hydrogen ionizatin fraction, chi(sub H) from 19% to 15%, respectively. The range of these derived quantities is due to the uncertainties in the local values of the neutral hydrogen and helium interstellar densities derived from both (1) solar backscatter measurements of Ly alpha lines of hydrogen and helium (1216 and 584 A), and (2) the average neutral densities along the line of sight to nearby stars. The local proton density produced by epsilon CMa is enough to allow the ionization mechanism of Ripken & Fahr (1983) to work at the heliopause and explain the discrepancy between the neutral hydrogen density derived from solar backscatter measurements and line-of-sight averages to nearby stars. A large value of electron density in the Local Cloud of n(sub e) is approximately 0.3-0.7/cu cm (T = 7000 K) has recently been reported by Lallement et al. (1994) using observations of Mg II and Mg I toward Sirius A. We show that if such a high value exists, it cannot result from the EUV stellar radiation field and, therefore, must be due to a strong diffuse source of EUV radiation.

Vallerga, J. V.; Welsh, B. Y.

1995-01-01

328

Epsilon Canis Majoris and the ionization of the local cloud  

NASA Astrophysics Data System (ADS)

The Lyman continuum radiation from the brightest extreme ultraviolet (EUV) source, the B2 II star epsilon Canis Majoris (Adara), is so intense that it dominates the local stellar EUV radiation field at wavelengths longer than 450 A and therefore sets a lower limit to the ionization of hydrogen in the Local Cloud. Using the EUV (70-730 A) spectrum of epsilon CMa taken with the Extreme Ultraviolet Explorer Satellite (EUVE) and simple models that extrapolate this spectrum to the Lyman edge at 912 A, we have determined the local interstellar hydrogen photionizatin parameter Gamma solely from epsilon CMa to be 1.1 x 10-15/s. This figure is a factor of 7 greater than previous estimates of Gamma calculated for all nearby stars combined (Bruhweiler & Cheng 1988). Using measured values of the density and temperature of neutral interstellar hydrogen gas in the Local Cloud, we derive a particle density of ionized hydrogen n(H(+)) and electrons ne of 0.015-0.019/cu cm assuming ionization equilibrium and a helium ionization fraction of less than 20%. These values correspond to a hydrogen ionizatin fraction, chiH from 19% to 15%, respectively. The range of these derived quantities is due to the uncertainties in the local values of the neutral hydrogen and helium interstellar densities derived from both (1) solar backscatter measurements of Ly alpha lines of hydrogen and helium (1216 and 584 A), and (2) the average neutral densities along the line of sight to nearby stars. The local proton density produced by epsilon CMa is enough to allow the ionization mechanism of Ripken & Fahr (1983) to work at the heliopause and explain the discrepancy between the neutral hydrogen density derived from solar backscatter measurements and line-of-sight averages to nearby stars. A large value of electron density in the Local Cloud of ne is approximately 0.3-0.7/cu cm (T = 7000 K) has recently been reported by Lallement et al. (1994) using observations of Mg II and Mg I toward Sirius A. We show that if such a high value exists, it cannot result from the EUV stellar radiation field and, therefore, must be due to a strong diffuse source of EUV radiation.

Vallerga, J. V.; Welsh, B. Y.

1995-05-01

329

Electric field measurements during the MAC/EPSILON campaign  

NASA Technical Reports Server (NTRS)

The MAC/EPSILON observational campaign in northern Norway involved the taking of three-axis electric field measurements of the middle atmosphere by means of five rocketborne payloads during October and November, 1987. Simultaneous horizontal electric field measurements made by two of the rocket flights were in general agreement in their limited overlap region. The more extensive horizontal E-field measurements exhibited a decreasing mapping function with decreasing altitude, thereby indicating the presence of fields from a local auroral patch. Small-scale variations in the horizontal fields of the lights were similar to observed wavelike variations in the neutral wind field.

Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Schmidlin, F. J.; Hoppe, U.-P.

1990-01-01

330

[Some aspects of the Clostridium difficile infection].  

PubMed

Clostridium difficile is now regarded as the most common nosocomial enteric pathogen. C. difficile infection has a wide spectrum of a clinical presentation ranging from asymptomatic carriage to the fulminant colitis. Antibiotic therapy is the most important risk factor in pathogen contagion, however other factors are also involved. Typical pathophysiology: 1. alteration of the indigenous colonic flora by antibodies, 2. ingestion of spores, 3. colonization by Clostridium difficile, 4. production of its toxins. Both entherotoxin A and cytotoxin B are active in human colon. The mode of action of these toxins is already quite well known. The main treatment includes withdrawal of the inducing agents, supported occasionally by oral Vancomycin and Metronidazole. Relapse is a major complication. PMID:9748892

Wójtowicz, A

1998-01-01

331

Evolving concepts in Clostridium difficile colitis  

Microsoft Academic Search

Clostridium difficile infection (CDI) is the most important cause of nosocomial diarrhea. The emergence of a hypervirulent strain and other factors\\u000a including antibiotic overuse contribute to the increasing incidence and severity of this potentially lethal infection. CDI\\u000a has been reported in persons previously considered as low risk, such as young healthy persons without exposure to health care\\u000a settings or antibiotics,

Naomi G. Diggs; Christina M. Surawicz

2009-01-01

332

Clostridium difficile infection: A critical overview  

Microsoft Academic Search

Clostridium difficile is a gram-positive, spore-forming, toxin-producing anaerobic bacillus identified as the causal agent of a variety of manifestations\\u000a typically isolated to the colon, but in its severe form, it can lead to sepsis and death. C. difficile infection due to a toxin gene variant strain (BI\\/NAP1) has been identified at the center of outbreaks and has resulted in\\u000a increased

Bayan Missaghi; August J. Valenti; Robert C. Owens Jr

2008-01-01

333

Clostridium difficile -associated diarrhea and colitis  

Microsoft Academic Search

PURPOSE: This review examines the pathogenesis, clinical manifestations, diagnosis, and current medical and operative strategies in the treatment ofClostridium difficile diarrhea and colitis. Prevention and future avenues of research are also investigated. METHODS: A review of the literature was conducted with the use of MEDLINE. RESULTS:C. difficile is a gram-positive, spore-forming bacterium capable of causing toxigenic colitis in susceptible patients,

Robert K. Cleary

1998-01-01

334

Clostridium difficile Infection: A Worldwide Disease  

PubMed Central

Clostridium difficile, an anaerobic toxigenic bacterium, causes a severe infectious colitis that leads to significant morbidity and mortality worldwide. Both enhanced bacterial toxins and diminished host immune response contribute to symptomatic disease. C. difficile has been a well-established pathogen in North America and Europe for decades, but is just emerging in Asia. This article reviews the epidemiology, microbiology, pathophysiology, and clinical management of C. difficile. Prompt recognition of C. difficile is necessary to implement appropriate infection control practices. PMID:24516694

Burke, Kristin E.

2014-01-01

335

Clostridium difficile infection in the elderly.  

PubMed

Clostridium difficile-associated illness is an increasingly prevalent and morbid condition. The elderly population is at a disproportionate risk of developing symptomatic disease and associated complications, including progression to severe or fulminant disease, and development of recurrent infections. This article analyzes the factors that influence C difficile disease propensity and severity, with particular attention directed toward features relevant to the rapidly aging population. PMID:24267604

Keller, Jonathan M; Surawicz, Christina M

2014-02-01

336

Clostridium septicum infection and hemolytic uremic syndrome.  

PubMed Central

Five cases of Clostridium septicum infection secondary to Escherichia coli O157-induced hemolytic uremic syndrome have been reported. We report on three cases (one of which is included in the above five) of dual Cl. septicum and E. coil infection; all three patients were exposed to farm animals. A common zoonotic source for Cl. septicum and E. coli O157 infections should be considered. Patients with hemolytic uremic syndrome should be treated aggressively and monitored closely for Cl. septicum superinfection. PMID:9621207

Barnham, M.; Weightman, N.

1998-01-01

337

Observations on the Wilson fermions in the epsilon regime  

E-print Network

We make several observations concerning the low quark mass region with Wilson fermions and how this is connected with the epsilon regime in the continuum. A transition from tiny cutoff effects to rather large discretization errors would take place in general with Wilson fermions if we lower the quark mass at finite lattice spacing. We argue that these two regions exhibit rather different behaviours concerning the coupling between cutoff effects and zero-modes. We interpolate between these two regimes adding to the continuum epsilon regime formulae, in the spirit of the Symanzik expansion, the relevant operators parametrising the leading cutoff effects. We compute the partition function, the chiral condensate, scalar and pseudo-scalar correlation functions. The final formulae can be used to fit lattice data to extract physical low energy constants, and to estimate systematic uncertainties coming from discretization errors. Moreover they suggest ways on how to remove these cutoff effects, the core of which are captured by the continuum zero modes.

Andrea Shindler

2008-12-12

338

Laboratory surveillance method for nosocomial Clostridium difficile diarrhea  

Microsoft Academic Search

Background: Clostridium Difficile is the most common infectious cause of endemic nosocomial diarrhea, but traditional surveillance methods for this infection can be time-consuming. The purpose of this article is to (1) describe a laboratory surveillance method for nosocomial diarrhea and nosocomial Clostridium difficile diarrhea (CDD) that does not require chart review and (2) describe some of the epidemiology of these

Joseph M. Mylotte

1998-01-01

339

Control of Clostridium perfringens-induced necrotic enteritis in broilers by target-released butyric acid, fatty acids and essential oils  

Microsoft Academic Search

The efficacy of target-released butyric acid, medium-chain fatty acids (C6 to C12 but mainly lauric acid) and essential oils (thymol, cinnamaldehyde, essential oil of eucalyptus) micro-encapsulated in a poly-sugar matrix to control necrotic enteritis was investigated. The minimal inhibitory concentrations of the different additives were determined in vitro, showing that lauric acid, thymol, and cinnamaldehyde are very effective in inhibiting

L. Timbermont; A. Lanckriet; J. Dewulf; N. Nollet; K. Schwarzer; F. Haesebrouck; R. Ducatelle; F. Van Immerseel

2010-01-01

340

Treatment of Chemotherapy-Resistant Human Ovarian Cancer Xenografts in C.B17\\/SCID Mice by Intraperitoneal Administration of Clostridium perfringens Enterotoxin  

Microsoft Academic Search

Ovarian cancer remains the most lethal gynecologic malig- nancy in the United States. Although many patients with advanced-stage disease initially respond to standard combi- nations of surgical and cytotoxic therapy, nearly 90% develop recurrence and inevitably die from the development of chemotherapy-resistant disease. The discovery of novel and effective therapy against chemotherapy-resistant\\/recurrent ovarian cancer remains a high priority. Using expression

Alessandro D. Santin; Stefania Cane; Stefania Bellone; Michela Palmieri; Eric R. Siegel; Maria Thomas; Juan J. Roman; Alexander Burnett; Sergio Pecorelli

2005-01-01

341

Plasmidome Interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum Converts Strains of Independent Lineages into Distinctly Different Pathogens  

PubMed Central

Clostridium botulinum (group III), Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains. PMID:25254374

Skarin, Hanna; Segerman, Bo

2014-01-01

342

High-Pressure Structural Study of Epsilon HNIW (CL-20)  

NASA Astrophysics Data System (ADS)

The structure of epsilon CL-20 at room temperature was investigated using synchrotron angle-dispersive x-ray diffraction experiments and Raman spectroscopy. For x-ray diffraction, the samples were compressed up to 6.3 GPa using a Merrill-Bassett diamond anvil cell (DAC) under both hydrostatic and non-hydrostatic conditions. Pressure — volume data were then fit to the Birch-Murnaghan equation of state to obtain an isothermal equation of state. No phase transition was observed within this pressure range. Raman spectroscopy was performed in the range of 50-1650 cm-1. The samples were compressed non-hydrostatically to 7.1 GPa. Changes in peak positions with increasing pressure were observed. Vibrational spectra were calculated using Hartree-Fock and density functional theory and a comparison was made with the experimental spectrum.

Gump, Jared C.; Wong, Chak P.; Zerilli, Frank J.; Peiris, Suhithi M.

2004-07-01

343

Coherent perfect absorption in epsilon-near-zero metamaterials  

NASA Astrophysics Data System (ADS)

In conventional materials, strong absorption usually requires that the material have either high loss or a large thickness-to-wavelength ratio (d/??1). We find the situation to be vastly different for bilayer structures composed of a metallic substrate and an anisotropic epsilon-near-zero (ENZ) metamaterial, where the permittivity in the direction perpendicular to its surface, ?z, vanishes. Remarkably, perfect absorption can occur in situations where the metamaterial is arbitrarily thin (d/??1) and arbitrarily low loss. Our numerical and analytical solutions reveal that under the conditions ?z?0 and ?(?z)??(?z), at perfect absorption there is a linear relationship between the thickness and the loss, which means the thickness of the absorber can be pushed to zero by reducing the material loss to zero. This counterintuitive behavior is explained in terms of coherent perfect absorption (or stimulated absorption) via critical coupling to a fast wave propagating along the ENZ layer.

Feng, Simin; Halterman, Klaus

2012-10-01

344

Three-dimensional Models of the Epsilon Aurigae Disk System  

NASA Astrophysics Data System (ADS)

The evolutionary state of the long-term binary star system, epsilon Aurigae, remains in question. Three-dimensional (3D), radiative transfer modeling with the HYPERION code (Robitaille 2011) enables inspection of the azimuthal temperature gradient found on the disk enveloping the secondary star (about 1150 K on the primary-facing side, i.e. ''noon"; about 550 K on the ''midnight" side). This modeling method requires specifications of the system's parameters, some of which are the following: binary separation, stellar masses, disk radius, disk composition, dust density, and dust size distribution. A systematic parameter selection provides constraints on both the disk material and binary separation, which directly corresponds to distance determination and evolutionary status. The importance of this work involves the inclusion of the F0 primary star in a 3D modeling environment. Preliminary results are presented. The authors are grateful to the estate of William Herschel Womble for support of astronomy at the University of Denver.

Pearson, Richard L.; Stencel, R. E.

2013-07-01

345

Discovery of the February epsilon Virginids (FEV, IAU #506)  

NASA Astrophysics Data System (ADS)

Combining first week of February CAMS and SonotaCo data resulted in the detection of at least one previously unreported shower. The February epsilon Virginids radiate from R.A. = 201.7° and Dec = +10.4°, with a mean geocentric velocity of 63.0 km/s at solar longitude 315.3°. The mean orbital elements of these meteoroids are q = 0.488 ± 0.021 AU, 1/a = 0.085 ± 0.095 1/AU, e = 0.958 ± 0.046, $i = 138.1° ± 1.3°, ? = 271.32deg; ± 3.7°, and ? = 315.3° ± 0.9°. The shower may originate from comet C/1808 F1 (Pons), if that comet is a Halley-type comet.

Steakley, Kathryn; Jenniskens, Peter

2013-08-01

346

Ferromagnetic resonance in $\\epsilon$-Co magnetic composites  

E-print Network

We investigate the electromagnetic properties of assemblies of nanoscale $\\epsilon$-cobalt crystals with size range between 5 nm to 35 nm, embedded in a polystyrene (PS) matrix, at microwave (1-12 GHz) frequencies. We investigate the samples by transmission electron microscopy (TEM) imaging, demonstrating that the particles aggregate and form chains and clusters. By using a broadband coaxial-line method, we extract the magnetic permeability in the frequency range from 1 to 12 GHz, and we study the shift of the ferromagnetic resonance with respect to an externally applied magnetic field. We find that the zero-magnetic field ferromagnetic resonant peak shifts towards higher frequencies at finite magnetic fields, and the magnitude of complex permeability is reduced. At fields larger than 2.5 kOe the resonant frequency changes linearly with the applied magnetic field, demonstrating the transition to a state in which the nanoparticles become dynamically decoupled. In this regime, the particles inside clusters can ...

Chalapat, Khattiya; Huuppola, Maija; Koponen, Lari; Johans, Christoffer; Ras, Robin H A; Ikkala, Olli; Oksanen, Markku A; Seppälä, Eira; Paraoanu, G S

2014-01-01

347

Shock initiation of an {epsilon}-CL-20-estane formulation  

SciTech Connect

The shock sensitivity of a pressed solid explosive formulation, LX-19, containing 95.2% by weight epsilon phase 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW) and 4.8% Estane binder, was determined using the wedge test and embedded manganin pressure gauge techniques. This formulation was shown to be slightly more sensitive than LX-14, which contains 95.5% HMX and 4.5% Estane binder. The measured pressure histories for LX-19 were very similar to those obtained using several HMX-inert binder formulations. An Ignition and Growth reactive model for LX-19 was developed which differed from those for HMX-inert binder formulations only by a 25% higher hot spot growth rate.

Tarver, C.M.; Simpson, R.L.; Urtiew, P.A.

1995-07-19

348

Middle atmosphere electrical structure during MAC/EPSILON  

NASA Technical Reports Server (NTRS)

Extensive use of rocket-launched probes during the the MAC/EPSILON campaign at the Andoya Rocket Range, Norway, has enabled the characterization of the region's electrical environment for all four flight series. The first rocket salvo was conducted during daylight (October 15, 1987) and the subsequent three occurred at night (October 21 and 28 and November 12, 1987), all of them during geomagnetically disturbed conditions. Measurements of polar electrical conductivity, ion mobility, and number density are presented, and their associated structure is investigated for local auroral ionization effects. This is believed to be the first time that Gerdien condenser mobility measurements have indicated a heavy-ion presence (positively charged aerosols) in the auroral mesopause region.

Mitchell, J. D.; Croskey, C. L.; Blood, S. P.; Li, C.; Hale, L. C.; Goldberg, R. A.

1990-01-01

349

Search for Planetary Companions of epsilon Eridani and Fomalhaut  

NASA Astrophysics Data System (ADS)

Fifteen percent of bright main sequence stars possess dusty circumstellar debris disks revealed by far-infrared photometry. These disks are signposts of planetary systems: collisions among larger, unseen parent bodies maintain the observed dust populations against losses to radiation pressure and P-R drag. Images of debris disks at optical, infrared, and millimeter wavelengths have shown central holes, rings, radial gaps, warps, and azimuthal asymmetries which indicate the presence of planetary mass perturbers. Two important nearby examples are epsilon Eridani, where clumps in the submm ring suggest resonant trapping by a planet; and Fomalhaut, where the elliptical ring geometry requires planetary perturbations to maintain its apsidal alignment. With its unparalled sensitivity at 4.5 microns, Spitzer offers a major opportunity to directly detect planetary perturbers as small as a few Jupiter masses in these two nearby disk systems. Initial IRAC full-array imaging of these targets has demonstrated the PSF subtraction techniques needed to detect faint companions. However, bright star saturation artifacts prevented us from probing the region interior to the rings, which are 20 arcsec in radius. To extend the companion search inward to 5" radius, we propose IRAC subarray imaging of epsilon Eri and Fomalhaut. Our goal is to directly detect the giant planets perturbing the dust rings, and characterize them as CH4 dwarfs from their characteristic [3.6]-[4.5] color. Observations will be made at two epochs, to roll the telescope diffraction pattern across the sky as an aid to rejecting PSF artifacts. The results will be uniquely sensitive to cold, low-mass planets ("Y dwarfs") that are undetectable from the ground at optical and near-IR wavelengths. These observations represent perhaps the best opportunity to directly image extrasolar planets during the Spitzer mission.

Marengo, Massimo; Carson, Joseph; Fazio, Giovanni; Megeath, Thomas; Schuster, Michael; Stapelfeldt, Karl; Werner, Michael

2006-05-01

350

Campaign Photometry During The 2010 Eclipse Of Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

Epsilon Aurigae is a long period (27.1 years) eclipsing binary star system with an eclipse that lasts nearly 2 years, but with severe ambiguities about component masses and shape. The current eclipse began on schedule in August of 2009. During the previous, 1982-1984 eclipse, an International Campaign was formed to coordinate a detailed study of the system. While that Campaign was deemed successful, the evolutionary status of the star system remained unclear. Epsilon Aurigae has been observed nearly continuously since the 1982 eclipse. The current Campaign was officially started in 2006. In addition to a Yahoo forum we have a dedicated web site and more than 18 online newsletters reporting photometry, spectroscopy, interferometry and polarimetry data. High quality UBVRIJH band photometric data since before the start of the current eclipse has been submitted. We explore the color differences among the light curves in terms of eclipse phases and archival data. At least one new model of the star system has been proposed since the current Campaign began: a low mass but very high luminosity F star plus a B star surrounded by a debris disk. The current eclipse and in particular the interferometry and spectroscopic data have caused new thoughts on defining eclipsing variable star contact points and phases of an eclipse. Second contact may not be the same point as start of totality and third contact may not be the same point as the start of egress and end of totality. In addition, the much awaited mid-eclipse brightening may or may not have appeared. This paper identifies the current Campaign contributors and the photometric data. This work was supported in part by the bequest of William Herschel Womble in support of astronomy at the University of Denver, by NSF grant 1016678 to the University of Denver.

Hopkins, Jeff; Stencel, R. E.

2011-01-01

351

epsilon-N-trimethyllysine availability regulates the rate of carnitine biosynthesis in the growing rat  

SciTech Connect

Rates of carnitine biosynthesis in mammals depend on the availability of substrates and the activity of enzymes subserving the pathway. This study was undertaken to test the hypothesis that the availability of epsilon-N-trimethyllysine is rate-limiting for synthesis of carnitine in the growing rat and to evaluate diet as a source of this precursor for carnitine biosynthesis. Rats apparently absorbed greater than 90% of a tracer dose of (methyl-/sup 3/H)epsilon-N-trimethyllysine, and approximately 30% of that was incorporated into tissues as (/sup 3/H)carnitine. Rats given oral supplements of epsilon-N-trimethyllysine (0.5-20 mg/d), but no dietary carnitine, excreted more carnitine than control animals receiving no dietary epsilon-N-trimethyllysine or carnitine. Rates of carnitine excretion increased in a dose-dependent manner. Tissue and serum levels of carnitine also increased with dietary epsilon-N-trimethyllysine supplementation. There was no evidence that the capacity for carnitine biosynthesis was saturated even at the highest level of oral epsilon-N-trimethyllysine supplementation. Common dietary proteins (casein, soy protein and wheat gluten) were found to be poor sources of epsilon-N-trimethyllysine for carnitine biosynthesis. The results of this study indicate that the availability of epsilon-N-trimethyllysine limits the rate of carnitine biosynthesis in the growing rat.

Rebouche, C.J.; Lehman, L.J.; Olson, L.

1986-05-01

352

Extreme Ultraviolet Spectrum of epsilon Canis Majoris between 600-920 Angstroms  

Microsoft Academic Search

We present the spectrum the brightest known extreme ultraviolet source, epsilon Canis Majoris, between 600 and 920 Angstroms. epsilon Canis Majoris (B2 II) was discovered to be the brightest EUV source in the sky during the Extreme Ultraviolet Explorer (EUVE) all-sky survey. Subsequent spectroscopic observations found an anomolously low neutral hydrogen column density, allowing for the first time the observation

E. Wilkinson; J. C. Green; R. McLean; B. Welsh

1996-01-01

353

Initial Evaluation of Processing Methods for an Epsilon Metal Waste Form  

Microsoft Academic Search

During irradiation of nuclear fuel in a reactor, the five metals, Mo, Pd, Rh, Ru, and Tc, migrate to the fuel grain boundaries and form small metal particles of an alloy known as epsilon metal ({var_epsilon}-metal). When the fuel is dissolved in a reprocessing plant, these metal particles remain behind with a residue - the undissolved solids (UDS). Some of

Jarrod V. Crum; Denis M. Strachan

2012-01-01

354

Magnetic properties of epsilon-Fe(3)N-GaN core-shell nanowires.  

PubMed

epsilon-Fe(3)N-GaN core-shell nanowires are synthesized by the wet chemical route and by nitridation of the Fe-Ga-oxide nanowires in flowing NH(3) (g). The encapsulation by the GaN shell protects the epsilon-Fe(3)N core and spin-glass-like cooperative ordering is observed at low temperatures. Magnetic disorder occurs at the epsilon-Fe(3)N-GaN interface, giving rise to the spin-glass-like state below 50 K because of the presence of anti-ferromagnetic (AF) mixed oxynitrides and ferromagnetic (FM) epsilon-Fe(3)N nitride and the random distribution of epsilon-Fe(3)N in the interface region. The spin-glass-like ordering is probed by relaxation and ac susceptibility experiments. PMID:20817963

Gajbhiye, N S; Bhattacharyya, Sayan

2005-10-01

355

Effect of epsilon subunit on the rotation of thermophilic Bacillus F1-ATPase.  

PubMed

F(1)-ATPase is an ATP-driven motor in which gammaepsilon rotates in the alpha(3)beta(3)-cylinder. It is attenuated by MgADP inhibition and by the epsilon subunit in an inhibitory form. The non-inhibitory form of epsilon subunit of thermophilic Bacillus PS3 F(1)-ATPase is stabilized by ATP-binding with micromolar K(d) at 25 degrees C. Here, we show that at [ATP]>2 microM, epsilon does not affect rotation of PS3 F(1)-ATPase but, at 200 nM ATP, epsilon prolongs the pause of rotation caused by MgADP inhibition while the frequency of the pause is unchanged. It appears that epsilon undergoes reversible transition to the inhibitory form at [ATP] below K(d). PMID:19265694

Tsumuraya, Masato; Furuike, Shou; Adachi, Kengo; Kinosita, Kazuhiko; Yoshida, Masasuke

2009-04-01

356

Neutropenic enterocolitis associated with Clostridium tertium.  

PubMed

A 15 year old boy being treated for relapsed acute lymphoblastic leukaemia developed severe diarrhoea and abdominal pain which worsened despite empirical antibiotic treatment. A right hemicolectomy was performed. The caecum and ascending colon showed changes typical of neutropenic enterocolitis. Clostridium tertium was isolated from faeces, blood cultures, and from the resected gut wall, with no evidence of other organisms capable of causing such a condition. As far as is known, this is the first reported case in which neutropenic enterocolitis has been associated with well documented C tertium infection, an organism previously described as a cause of bacteraemia in neutropenic patients. PMID:8459041

Coleman, N; Speirs, G; Khan, J; Broadbent, V; Wight, D G; Warren, R E

1993-02-01

357

Annotation of the Clostridium Acetobutylicum Genome  

SciTech Connect

The genome sequence of the solvent producing bacterium Clostridium acetobutylicum ATCC824, has been determined by the shotgun approach. The genome consists of a 3.94 Mb chromosome and a 192 kb megaplasmid that contains the majority of genes responsible for solvent production. Comparison of C. acetobutylicum to Bacillus subtilis reveals significant local conservation of gene order, which has not been seen in comparisons of other genomes with similar, or, in some cases, closer, phylogenetic proximity. This conservation allows the prediction of many previously undetected operons in both bacteria.

Daly, M. J.

2004-06-09

358

Antibodies for treatment of Clostridium difficile infection.  

PubMed

Antibodies for the treatment of Clostridium difficile infection (CDI) have been demonstrated to be effective in the research and clinical environments. Early uncertainties about molecular and treatment modalities now appear to have converged upon the systemic dosing of mixtures of human IgG1. Although multiple examples of high-potency monoclonal antibodies (MAbs) exist, significant difficulties were initially encountered in their discovery. This minireview describes historical and contemporary MAbs and highlights differences between the most potent MAbs, which may offer insight into the pathogenesis and treatment of CDI. PMID:24789799

Humphreys, David P; Wilcox, Mark H

2014-07-01

359

CSFGGiardia sirapseudonana  

E-print Network

acetobutylicum Clostridium tetani Clostridium perfringens Staphylococcus aureus MW2Staphylococcus aureus N315 Staphylococcus aureus Mu50 Staphylococcus epidermidis Listeria innocuaListeria monocytogenes F2365 Listeria

Shoubridge, Eric

360

Polymerase Epsilon Mutations Accelerate Mutation Rates in Colorectal and Endometrial Cancer - David Wheeler, TCGA Scientific Symposium 2012  

Cancer.gov

Home News and Events Multimedia Library Videos Polymerase Epsilon Mutations in Colorectal and Endometrial Cancer - David Wheeler Polymerase Epsilon Mutations Accelerate Mutation Rates in Colorectal and Endometrial Cancer - David Wheeler, TCGA Scientific

361

Complete Genome Sequence of Clostridium clariflavum DSM 19732  

PubMed Central

Clostridium clariflavum is a Cluster III Clostridium within the family Clostridiaceae isolated from thermophilic anaerobic sludge (Shiratori et al, 2009). This species is of interest because of its similarity to the model cellulolytic organism Clostridium thermocellum and for the ability of environmental isolates to break down cellulose and hemicellulose. Here we describe features of the 4,897,678 bp long genome and its annotation, consisting of 4,131 protein-coding and 98 RNA genes, for the type strain DSM 19732. PMID:22675603

Izquierdo, Javier A.; Goodwin, Lynne; Davenport, Karen W.; Teshima, Hazuki; Bruce, David; Detter, Chris; Tapia, Roxanne; Han, Shunsheng; Land, Miriam; Hauser, Loren; Jeffries, Cynthia D.; Han, James; Pitluck, Sam; Nolan, Matt; Chen, Amy; Huntemann, Marcel; Mavromatis, Konstantinos; Mikhailova, Natalia; Liolios, Konstantinos; Woyke, Tanja; Lynd, Lee R.

2012-01-01

362

Hubble Space Telescope Cycle 11 General Observer Proposal The Hunt for Epsilon Eridani c to Study its Earthly  

E-print Network

Hubble Space Telescope Cycle 11 General Observer Proposal The Hunt for Epsilon Eridani c to Study upper atmosphere. #12;Mr John Lewis The Hunt for Epsilon Eridani c to Study its Earthly Properties 0 Grand total orbit request 30 2 #12;Mr John Lewis The Hunt for Epsilon Eridani c to Study its

Walter, Frederick M.

363

Meso-alpha,epsilon-diaminopimelate D-dehydrogenase: distribution and the reaction product.  

PubMed Central

A high activity of meso-alpha-epsilon-diaminopimelate dehydrogenase was found in extracts of Bacillus sphaericus, Brevibacterium sp., Corynebacterium glutamicum, and Proteus vulgaris among bacteria tested. B. sphaericus IFO 3525, in which the enzyme is most abundant, was chosen to study the enzyme reaction. The enzyme was not induced by the addition of meso-alpha-epsilon-diaminopimelate to the growth medium. The reaction product was isolated and identified as alpha-amino-epsilon-ketopimelate by a comparison of the properties of its 2,4-dinitrophenylhydrazone with those of an authentic sample in silica gel thin-layer chromatography, absorption, infrared and proton nuclear magnetic resonance spectrometry, and elemental analyses. The alpha-amino-epsilon-ketopimelate formed enzymatically was decarboxylated by H2O2 to yield L-alpha-aminoadipate. This suggests that the amino group with D-configuration in the substrate is oxidatively deaminated; the enzyme is a D-amino acid dehydrogenase. L-alpha-Amino-epsilon-ketopimelate undergoes spontaneous dehydration to the cyclic delta1-piperideine-2,6-dicarboxylate. The enzyme reaction is reversible, and meso-alpha-epsilon-diaminopimelate was formed in the reductive amination of L-alpha-epsilon-ketopimelate. PMID:762012

Misono, H; Togawa, H; Yamamoto, T; Soda, K

1979-01-01

364

Conformational transitions of subunit epsilon in ATP synthase from thermophilic Bacillus PS3.  

PubMed

Subunit epsilon of bacterial and chloroplast F(O)F(1)-ATP synthase is responsible for inhibition of ATPase activity. In Bacillus PS3 enzyme, subunit epsilon can adopt two conformations. In the "extended", inhibitory conformation, its two C-terminal alpha-helices are stretched along subunit gamma. In the "contracted", noninhibitory conformation, these helices form a hairpin. The transition of subunit epsilon from an extended to a contracted state was studied in ATP synthase incorporated in Bacillus PS3 membranes at 59 degrees C. Fluorescence energy resonance transfer between fluorophores introduced in the C-terminus of subunit epsilon and in the N-terminus of subunit gamma was used to follow the conformational transition in real time. It was found that ATP induced the conformational transition from the extended to the contracted state (half-maximum transition extent at 140 microM ATP). ADP could neither prevent nor reverse the ATP-induced conformational change, but it did slow it down. Acid residues in the DELSEED region of subunit beta were found to stabilize the extended conformation of epsilon. Binding of ATP directly to epsilon was not essential for the ATP-induced conformational change. The ATP concentration necessary for the half-maximal transition (140 microM) suggests that subunit epsilon probably adopts the extended state and strongly inhibits ATP hydrolysis only when the intracellular ATP level drops significantly below the normal value. PMID:20141757

Feniouk, Boris A; Kato-Yamada, Yasuyuki; Yoshida, Masasuke; Suzuki, Toshiharu

2010-02-01

365

Extreme Ultraviolet Spectrum of epsilon Canis Majoris between 600-920 Angstroms  

NASA Astrophysics Data System (ADS)

We present the spectrum the brightest known extreme ultraviolet source, epsilon Canis Majoris, between 600 and 920 Angstroms. epsilon Canis Majoris (B2 II) was discovered to be the brightest EUV source in the sky during the Extreme Ultraviolet Explorer (EUVE) all-sky survey. Subsequent spectroscopic observations found an anomolously low neutral hydrogen column density, allowing for the first time the observation of a B star between 500 and 730 Angstroms. Unexpectedly, the spectrum is still increasing at 730 Angstroms. By observing epsilon CMa between 600 and 920 Angstroms, the spectrum of epsilon CMa is now complete from the x-ray thru to the infrared. This provides a unique opportunity for studying the atmospheres of B stars and refining the current atmospheric models, which cannot currently model the stellar flux from epsilon CMa. epsilon CMa was observed on March 4, 1996 from White Sands Missile Range using a sounding rocket borne spectrograph. The spectrum has a resolution ranging between 1000 at 735 Angstroms to 450 at 900 Angstroms . Two data sets were acquired during the flight; one with a tin filter, to block out potential scattered light longward of 920 Angstroms, and one without the filter. We will present the spectrum epsilon CMa and discuss and the current state of our analysis.

Wilkinson, E.; Green, J. C.; McLean, R.; Welsh, B.

1996-05-01

366

Simulations of free shear layers using a compressible kappa-epsilon model  

NASA Technical Reports Server (NTRS)

A two-dimensional, compressible Navier-Stokes equation with a k-epsilon turbulence model is solved numerically to simulate the flow of a compressible free shear layer. The appropriate form of k and epsilon equations for compressible flow is discussed. Sarkar's modeling is adopted to simulate the compressibility effects in the k and epsilon equations. The numerical results show that the spreading rate of the shear layers decreases with increasing convective Mach number. In addition, favorable comparison was found between the calculated results and experimental data.

Yu, S. T.; Chang, C. T.; Marek, C. J.

1991-01-01

367

Near-perfect absorption in epsilon-near-zero structures with hyperbolic dispersion  

E-print Network

We investigate the interaction of polarized electromagnetic waves with hyperbolic metamaterial structures, whereby the in-plane permittivity component $\\epsilon_x$ is opposite in sign to the normal component $\\epsilon_z$. We find that when the thickness of the metamaterial is smaller than the wavelength of the incident wave, hyperbolic metamaterials can absorb significantly higher amounts of electromagnetic energy compared to their conventional counterparts. We also demonstrate that for wavelengths leading to $\\Re(\\epsilon_z) \\approx 0$, near-perfect absorption arises and persists over a range of frequencies and subwavelength structure thicknesses.

Halterman, Klaus

2014-01-01

368

Improved staggered eigenvalues and epsilon regime universality in SU(2)  

NASA Astrophysics Data System (ADS)

We study the low-lying modes of staggered Dirac operators for quenched SU(2) and show that improvement changes the distribution from lattice-like to continuum-like at lattice spacings rep- resentative of current dynamical SU(3) simulations. Epsilon regime universality predicts different distributions for the low-lying eigenvalues of the continuum and lattice staggered Dirac operators. At lattice spacings around 0.07 fm we show that improved staggered eigenvalues have the continuum distribution (as predicted by the chiral Orthogonal Ensemble of random matrices), whilst unimproved fall on the discrete distribution (as per the chiral Symplectic Ensemble). The crossover is much more rapid than for SU(3). In addition, improved staggered fermions give a good approximation to the Atiyah-Singer index theorem, appear to satisfy the Banks-Casher relation and show clear taste-degeneracy for the non- zero modes. All this indicates that taste-changing interactions are well under control at lattice spacings 0.07 - 0.13 fm, matching our findings for SU(3).

Hart, Alistair

2006-12-01

369

Quantum plasmon effects in epsilon-near-zero metamaterials  

E-print Network

Dispersion properties of metals and propagation of quantum bulk plasmon in the high photon energy regime are studied. The nonlocal dielectric permittivity of a metal is determined by the quantum plasma effects and is calculated by applying the Wigner equation in the kinetic theory and taking into account the electron lattice collisions. The properties of epsilon near zero material are investigated in a thin gold film. The spectrum and the damping rate of the quantum bulk plasmon are obtained for a wide range of energies, and the electron wave function is analytically calculated in both classical and quantum limits. It is shown that the quantum bulk plasmons exist with a propagation length of 1 to 10nm, which strongly depends on the electron energy. The propagation length is found to be much larger than the propagation length in the classical regime which is comparable to the atomic radius and the average inter particle distance. It is found that the spatial localization of the electron wave function is extend...

Moaied, M; Ostrikov, K

2014-01-01

370

Small Telescope Infrared Photometry of the epsilon Aurigae Eclipse  

NASA Astrophysics Data System (ADS)

Near-infrared photometry of epsilon Aurigae, in the H- and J-bands, was undertaken during the 2009-2011 eclipse using telescopes of moderate size (8-inch and 14-inch diameter). Instruments of this size successfully collected scientific data in the H- and J-bands. Observations were made from the campus of East Tennessee State University (ETSU), Johnson City, Tennessee, the campus of King College, Bristol, Tennessee, and from the author's home. Signal/Noise ratios of approximately 45 were obtained during times of maximum eclipse. Higher S/N ratios could have been obtained by extending the length of time on target. S/N ratios of almost 100 were obtained outside of eclipse. The infrared light curves produced closely parallel the light curve in the visual range (V), being about 0.5 magnitude brighter in H and 0.7 magnitude brighter in J. The eclipse was easily detected and followed throughout its duration. The rate of ingress was shallower than the rate of egress in both the H- and J-bands. The background variations of the primary star were readily detected.

Rutherford, T. P.

2012-06-01

371

Reinforcing poly(epsilon-caprolactone) nanofibers with cellulose nanocrystals.  

PubMed

We studied the use of cellulose nanocrystals (CNXs) obtained after acid hydrolysis of ramie cellulose fibers to reinforce poly(epsilon-caprolactone) (PCL) nanofibers. Chemical grafting with low-molecular-weight PCL diol onto the CNXs was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Grafting was confirmed via infrared spectroscopy and thermogravimetric analyses. The polymer matrix consisted of electrospun nanofibers that were collected as nonwoven webs. The morphology as well as thermal and mechanical properties of filled and unfilled nanofibers were elucidated by scanning electron microscopy, differential scanning calorimetry, and dynamic mechanical analysis, respectively. The addition of CNXs into PCL produced minimal changes in the thermal behavior of the electrospun fibers. However, a significant improvement in the mechanical properties of the nanofibers after reinforcement with unmodified CNXs was confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNXs showed ca. 1.5-fold increase in Young's modulus and the ultimate strength compared to PCL webs. Compared to the case of grafted nanocrystals, the unmodified ones imparted better morphological homogeneity to the nanofibrillar structure. The grafted nanocrystals had a negative effect on the morphology of nonwoven webs in which individual nanofibers became annealed during the electrospinning process and, therefore, could not be compared to neat PCL nonwoven webs. A rationalization for the different effects of grafted and unmodified CNXs in reinforcing PCL nanofibers is provided. PMID:20355825

Zoppe, Justin O; Peresin, Maria S; Habibi, Youssef; Venditti, Richard A; Rojas, Orlando J

2009-09-01

372

Discovery of the February Epsilon Virginids (FEV, IAU#506)  

NASA Astrophysics Data System (ADS)

Halley type comets are relatively few, but at Earth they are sampled over a large part of the inner solar system because dust accumulates in comparatively stable orbits. We have detected a new meteor shower with a Halley-type orbit, the February epsilon Virginids (FEV), from video observations with the Cameras for All-Sky Meteor Surveillance (CAMS) and by examining orbits listed in the SonataCo Japanese database. Twenty-two meteors were detected during the period from February 1st through February 9th of 2008 to 2012 that are part of this shower. The FEVs originate from the geocentric radiant of R.A. = 201.66° and Dec = +10.39° with a mean geocentric velocity of 63.01 km/s. The mean orbital elements of these meteoroids are q = (0.488 ± 0.021) AU, 1/a = ( 0.085 ± 0.095) 1/AU, e = 0.958 ± 0.046, i = 138.05° ± 1.28°, ? = 271.15° ± 3.70°, ? = 315.26 ± 0.86°, and ? = 228.12°. We investigated whether this meteoroid stream could have originated from comets C/1978 T3 (Bradfield), C/1808 F1 (Pons), or C/1939 H1 (Jurlof-Achmarof-Hassel). If the parent body can be identified, we can determine when the comet was first captured into a low perihelion distance orbit. Future examination of the shower will allow us to examine the physical properties of the parent comet.

Steakley, Kathryn; Jenniskens, P. M.

2013-01-01

373

Polymerase Epsilon Is Required To Maintain Replicative Senescence?†  

PubMed Central

Replicative senescence is a permanent cell cycle arrest in response to extensive telomere shortening. To understand the mechanisms behind a permanent arrest, we screened for factors affecting replicative senescence in budding yeast lacking telomere elongation pathways. Intriguingly, we found that DNA polymerase epsilon (Pol ?) acts synergistically with Exo1 nuclease to maintain replicative senescence. In contrast, the Pol ?-associated checkpoint and replication protein Mrc1 facilitates escape from senescence. To understand this paradox, in which DNA-synthesizing factors cooperate with DNA-degrading factors to maintain arrest, whereas a checkpoint protein opposes arrest, we analyzed the dynamics of double- and single-stranded DNA (ssDNA) at chromosome ends during senescence. We found evidence for cycles of DNA resection, followed by resynthesis. We propose that resection of the shortest telomere, activating a Rad24Rad17-dependent checkpoint pathway, alternates in time with an Mrc1-regulated Pol ? resynthesis of a short, double-stranded chromosome end, which in turn activates a Rad953BP1-dependent checkpoint pathway. Therefore, instead of one type of DNA damage, different types (ssDNA and a double-strand break-like structure) alternate in a “vicious circle,” each activating a different checkpoint sensor. Every time resection and resynthesis switches, a fresh signal initiates, thus preventing checkpoint adaptation and ensuring the permanent character of senescence. PMID:21321081

Deshpande, Abhyuday M.; Ivanova, Iglika G.; Raykov, Vasil; Xue, Yuan; Maringele, Laura

2011-01-01

374

Fumarate dissimilation and differential reductant flow by Clostridium formicoaceticum and Clostridium aceticum  

Microsoft Academic Search

Methanol and the O-methyl group of vanillate did not support the growth of Clostridium formicoaceticum in defined medium under CO2-limited conditions; however, they were growth supportive when fumarate was provided concomitantly. Fumarate alone was not growth supportive under these conditions. Fumarate reduction (dissimilation) to succinate was the predominant electron-accepting, energy-conserving process for methanol-derived reductant under CO2-limited conditions. However, when both

Carola Matthies; Anja Freiberger; Harold L. Drake

1993-01-01

375

Clostridium difficileClostridium difficile An infection Control NursesAn infection Control Nurses  

E-print Network

Audits EducationEducation #12;MonitoringMonitoring Hospital Acquired C diff 2004 - 2005, XXX 0 5 10 15 20 25 30 35/ReportingMonitoring/Reporting Hospital Acquired C. diff, Ward XXX, 2004- 2006 0 1 2 3 4 5 6 J2004 F M A M J J A S O N DJan-05 F M A M J JClostridium difficileClostridium difficile An infection Control NursesAn infection Control Nurses

Glasgow, University of

376

Hemolytic uremic syndrome associated with Clostridium difficile infection.  

PubMed

We report 3 cases of Clostridium difficile-associated hemolytic uremic syndrome (HUS) with biopsy proven renal thrombotic microangiopathy. Two patients with acute renal failure were kidney transplants recipients whereas the third patient developed renal failure in the native kidneys. The presentation was preceded by acute diarrhea and stool. Clostridium difficile toxin was detected in all the 3 patients. Stool studies were negative for Escherichia coli, Shigella dysenteriae and other enteric pathogens. The diagnosis of Clostridium difficile-associated hemolytic uremic syndrome was suspected due to presence of thrombocytopenia, microangiopathic hemolytic anemia and biopsy proven renal thrombotic microangiopathy without another clinically apparent cause. This case series suggest that Clostridium difficile infection may cause renal failure due to thrombotic microangiopathy (TMA) and should be considered in the differential diagnosis of diarrhea-associated HUS. PMID:23320969

Alvarado, Anthony S; Brodsky, Sergey V; Nadasdy, Tibor; Singh, Neeraj

2014-04-01

377

Clostridium difficile in the community: time to clean up?  

PubMed

Recent drives to eradicate Clostridium difficile from hospitals mean that there are now more cases of the bacteria originating in the community than in hospitals. Linda Nazarko argues that community health now needs our attention. PMID:25284189

2014-10-01

378

Methylenetetrahydrofolate dehydrogenase from Clostridium formicoaceticum and methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase (combined) from Clostridium thermoaceticum  

SciTech Connect

Methylenetetrahydrofolate dehydrogenase is widely distributed and has been found in every cell type investigated. The NAD-specific enzyme has been purified to homogeneity from Clostridium formicoaceticum and the NADP-specific enzyme has been obtained from Clostridium thermoaceticum. Other sources of the NADP-specific enzyme are Streptococcus species, Escherichia coli, Clostridium cylindrosporum, Salmonella typhimurium, yeast, liver from various animals, calf thymus, and plants. The NAD-specific enzyme has been demonstrated in Acetobacterium woodii, some methane bacteria, and in Ehrlich ascites tumor cells. Of considerable interest are the observations that in porcine and ovine livers, as well as in yeast, methylenetetrahydrofolate dehydrogenase purified to homogeneity also contains methylenetetrahydrofolate cyclohydrolase and formyltetrahydrofolate synthetase activities. Now it appears that the purified methylenetetrahydrofolate dehydrogenase from C. thermoaceticum also has cyclohydrolase but not synthetase activity. Methylenetetrahydrofolate dehydrogenase has been discussed previously in this series, as has methenyltetrahydrofolate cyclohydrolase. In C. formicoaceticum and C. thermoaceticum these tetrahydrofolate-dependent enzymes participate in a sequence of metabolic reactions by which carbon dioxide is reduced to the methyl group of 5-methyltetrahydrofolate which in turn is utilized for the synthesis of acetate. This pathway provides the mechanism for disposing of reducing equivalents generated in glycolysis.

Ljungdahl, L.G.; O'Brien, W.E.; Moore, M.R.; Liu, M.T.

1980-01-01

379

Modulation of nucleotide binding to the catalytic sites of thermophilic F(1)-ATPase by the epsilon subunit: implication for the role of the epsilon subunit in ATP synthesis.  

PubMed

Effect of epsilon subunit on the nucleotide binding to the catalytic sites of F(1)-ATPase from the thermophilic Bacillus PS3 (TF(1)) has been tested by using alpha(3)beta(3)gamma and alpha(3)beta(3)gammaepsilon complexes of TF(1) containing betaTyr341 to Trp substitution. The nucleotide binding was assessed with fluorescence quenching of the introduced Trp. The presence of the epsilon subunit weakened ADP binding to each catalytic site, especially to the highest affinity site. This effect was also observed when GDP or IDP was used. The ratio of the affinity of the lowest to the highest nucleotide binding sites had changed two orders of magnitude by the epsilon subunit. The differences may relate to the energy required for the binding change in the ATP synthesis reaction and contribute to the efficient ATP synthesis. PMID:19785990

Yasuno, Taichi; Muneyuki, Eiro; Yoshida, Masasuke; Kato-Yamada, Yasuyuki

2009-12-11

380

Navier-Stokes cascade analysis with a stiff Kappa-Epsilon turbulence solver  

NASA Technical Reports Server (NTRS)

The two dimensional, compressible, thin layer Navier-Stokes equations with the Baldwin-Lomax turbulence model and the kinetic energy-energy dissipation (k-epsilon) model are solved numerically to simulate the flow through a cascade. The governing equations are solved for the entire flow domain, without the boundary layer assumptions. The stiffness of the k-epsilon equations is discussed. A semi-implicit, Runge-Kutta, time-marching scheme is developed to solve the k-epsilon equations. The impact of the k-epsilon solver on the explicit Runge-Kutta Navier-Stokes solver is discussed. Numerical solutions are presented for two dimensional turbulent flow over a flat plate and a double circular arc cascade and compared with experimental data.

Liu, Jong-Shang; Sockol, Peter M.; Prahl, Joseph M.

1987-01-01

381

Low Reynolds number kappa-epsilon modeling with the aid of direct simulation data  

NASA Technical Reports Server (NTRS)

The constant C(sub mu) and the near-wall damping function f(sub mu) in the eddy-viscosity relation of the kappa-epsilon model are evaluated from direct numerical simulation (DNS) data for developed channel and boundary layer flow at two Reynolds numbers each. Various existing f(sub mu) model functions are compared with the DNS data, and a new function is fitted to the high-Reynolds-number channel flow data. The epsilon-budget is computed for the fully developed channel flow. The relative magnitude of the terms in the epsilon-equation is analyzed with the aid of scaling arguments, and the parameter governing this magnitude is established. Models for the sum of all source and sink terms in the epsilon-equation are tested against the DNS data, and an improved model is proposed.

Rodi, W.; Mansour, N. N.

1990-01-01

382

Ultrafast plasmonics using transparent conductive oxide hybrids in the epsilon-near-zero regime  

E-print Network

and as heat reflecting windows. Recently, metal oxides such as indium-tin oxide (ITO) and aluminium- doped zinc oxide haveUltrafast plasmonics using transparent conductive oxide hybrids in the epsilon-near-zero regime

Zheludev, Nikolay

383

Low Reynolds number k-epsilon modelling with the aid of direct simulation data  

NASA Technical Reports Server (NTRS)

The constant C sub mu and the near-wall damping function f sub mu in the eddy-viscosity relation of the k-epsilon model are evaluated from direct numerical simulation (DNS) data for developed channel and boundary layer flow at two Reynolds numbers each. Various existing f sub mu model functions are compared with the DNS data, and a new function is fitted to the high-Reynolds-number channel flow data. The epsilon-budget is computed for the fully developed channel flow. The relative magnitude of the terms in the epsilon-equation is analyzed with the aid of scaling arguments, and the parameter governing this magnitude is established. Models for the sum of all source and sink terms in the epsilon-equation are tested against the DNS data, and an improved model is proposed.

Rodi, W.; Mansour, N. N.

1993-01-01

384

Calculations of Diffuser Flows with an Anisotropic K-Epsilon Model  

NASA Technical Reports Server (NTRS)

A newly developed anisotropic K-epsilon model is applied to calculate three axisymmetric diffuser flows with or without separation. The new model uses a quadratic stress-strain relation and satisfies the realizability conditions, i.e., it ensures both the positivity of the turbulent normal stresses and the Schwarz' inequality between any fluctuating velocities. Calculations are carried out with a finite-element method. A second-order accurate, bounded convection scheme and sufficiently fine grids are used to ensure numerical credibility of the solutions. The standard K-epsilon model is also used in order to highlight the performance of the new model. Comparison with the experimental data shows that the anisotropic K-epsilon model performs consistently better than does the standard K-epsilon model in all of the three test cases.

Zhu, J.; Shih, T.-H.

1995-01-01

385

Prolonged Survival of Kidney Homotransplants in Dog treated by Epsilon-acetamide Caproic Acid  

Microsoft Academic Search

IN previous experiments the inhibiting influence of epsilon-acetamide caproic acid (EAACA) on Sanarelli-Schwartzmann hæmorrhagic skin reaction in rabbits, as well as on rejection of skin transplants in rats, was demonstrated1-3.

A. Bertelli; M. Bisiani; L. Cerrini; A. Confalonieri; V. Libro; E. Lodi; M. Proto

1964-01-01

386

Clostridium tertium bacteremia: 2 cases and review.  

PubMed

Clostridium tertium bacteremia is unusual, seen most often with gastrointestinal disease and/or neutropenia. Two cases are described. The first was a 19-yr-old female with acute leukemia, who developed gastrointestinal symptoms and C. tertium bacteremia while neutropenic. The second was a 57-yr-old female with quiescent ulcerative colitis, who presented with fever, rigors and epigastric pain. Four organisms including C. tertium were isolated from blood cultures. This patient responded to broad spectrum antimicrobial therapy, whereas the first patient required the addition of specific agents to recover. C. tertium is aerotolerant and thus can be misidentified as a Bacillus or Corynebacterium spp. Our isolates had a distinctive Gram stain morphology, were catalase negative and failed to sporulate aerobically--this aided in the recognition of this significant Gram-positive bacillus. PMID:8714277

Gosbell, I B; Johnson, C G; Newton, P J; Jelfs, J

1996-01-01

387

The Enterotoxicity of Clostridium difficile Toxins  

PubMed Central

The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by acting directly on intestinal epithelial cells. Alternatively, the toxins may target immune cells and neurons once the intestinal epithelial barrier is disrupted. The toxins may also act indirectly by stimulating cells to produce chemokines, proinflammatory cytokines, neuropeptides and other neuroimmune signals. This review considers the mechanisms of TcdA- and TcdB-induced enterotoxicity, and recent developments in this field. PMID:22069662

Sun, Xingmin; Savidge, Tor; Feng, Hanping

2010-01-01

388

Transcriptional organization of the Clostridium acetobutylicum genome  

PubMed Central

Prokaryotic genes are frequently organized in multicistronic operons (or transcriptional units, TUs), and usually the regulatory motifs for the whole TU are located upstream of the first TU gene. Although the number of sequenced genomes has increased dramatically, experimental information on TU organization is extremely limited. Even for organisms as extensively studied as Escherichia coli and Bacillus subtilis, TU annotation is far from complete. It therefore becomes imperative to rely on computational approaches to complement experimental information. Here we present a TU map for the obligate anaerobe Clostridium acetobutylicum ATCC 824. This map is largely based on the distance between pairs of consecutive genes but enhanced and refined by predictions of several types of promoters (?A, ?E and ?F/G) and rho-independent terminator structures. Based on the set of known C.acetobutylicum TUs, the presented TU map offers an 88% prediction accuracy. PMID:15060177

Paredes, Carlos J.; Rigoutsos, Isidore; Papoutsakis, E. Terry

2004-01-01

389

Epidemiology of Clostridium difficile infection in Asia  

PubMed Central

While Clostridium difficile infection (CDI) has come to prominence as major epidemics have occurred in North America and Europe over the recent decade, awareness and surveillance of CDI in Asia have remained poor. Limited studies performed throughout Asia indicate that CDI is also a significant nosocomial pathogen in this region, but the true prevalence of CDI remains unknown. A lack of regulated antibiotic use in many Asian countries suggests that the prevalence of CDI may be comparatively high. Molecular studies indicate that ribotypes 027 and 078, which have caused significant outbreaks in other regions of the world, are rare in Asia. However, variant toxin A-negative/toxin B-positive strains of ribotype 017 have caused epidemics across several Asian countries. Ribotype smz/018 has caused widespread disease across Japan over the last decade and more recently emerged in Korea. This review summarises current knowledge on CDI in Asian countries. PMID:23816346

2013-01-01

390

Immune responses to Clostridium difficile infection  

PubMed Central

Clostridium difficile is the causal agent of antibiotic-associated diarrhea and is a leading cause of hospital-acquired infections in the US. C. difficile has been known to cause severe diarrhea and colitis for more than 30 years, but the emergence of a newer, hypervirulent strain of C. difficile (BI/NAP1) has further compounded the problem, and recently both number of cases and mortality associated with C. difficile-associated diarrhea has been increasing. One of the major drivers of disease pathogenesis is believed to be an excessive host inflammatory response. A better understanding of the host inflammation and immune mechanisms that modulate the course of disease and control host susceptibility to C. difficile could lead to novel (host-targeted) strategies for combating the challenges posed by this deadly infection. This review summarizes our current knowledge of the host inflammatory response during C. difficile infection. PMID:23084763

Madan, Rajat; Petri, William A.

2012-01-01

391

Current state of Clostridium difficile treatment options.  

PubMed

Recent reports of reduced response to standard therapies for Clostridium difficile infection (CDI) and the risk for recurrent CDI that is common with all currently available treatment agents have posed a significant challenge to clinicians. Current recommendations include metronidazole for treatment of mild to moderate CDI and vancomycin for severe CDI. Results from small clinical trials suggest that nitazoxanide and teicoplanin may be alternative options to standard therapies, whereas rifaximin has demonstrated success in uncontrolled trials for the management of multiple recurrences. Anecdotal reports have also suggested that tigecycline might be useful as an adjunctive agent for the treatment of severe complicated CDI. Reports of resistance will likely limit the clinical use of fusidic acid and bacitracin and, possibly, rifaximin if resistance to this agent becomes widespread. Treatment of patients with multiple CDI recurrences and those with severe complicated CDI is based on limited clinical evidence, and new treatments or strategies are needed. PMID:22752868

Venugopal, Anilrudh A; Johnson, Stuart

2012-08-01

392

Association Between Appendectomy and Clostridium difficile Infection  

PubMed Central

Background Recent theory proposes that the appendix functions as a reservoir for commensal bacteria, and serves to re-inoculate the colon with normal flora in the event of pathogen exposure or purging of intestinal flora. If true, we reasoned that flora from a normal appendix could provide protection against Clostridium difficile. We conducted this investigation to examine the protective effect of an intact appendix and test the hypothesis that prior appendectomy will be more common among patients with a positive test for C. difficile as compared with patients who test negative. Methods We contacted patients who had undergone C. difficile testing and asked them whether or not they had a prior appendectomy. Using their responses and results from Toxin A & B EIA tests, we calculated the difference in appendectomy rates between those who tested positive for C. difficile, and those who tested negative. We considered a positive 15% absolute difference to represent a significant increase in appendectomy rate. Results We enrolled 257 patients. Among the 136 who tested positive for C. difficile, 27 (19.9%) had prior appendectomies, while among 121 patients testing negative for C. difficile, 38 (31.4%) had prior appendectomies, yielding a difference in appendectomy rates of -11.6% (95% Confidence Interval: -21.6% to -0.9%). Conclusions The rate of prior appendectomy was actually lower among patients with a positive C. difficile test as compared to those with a negative test. Conversely, patients who tested positive for C. difficile were more likely to have an intact appendix than those who tested negative. These results suggest that rather than being protective, an intact appendix appears to promote C. difficile acquisition, carriage, and disease. Keywords Clostridium difficile; Appendix; Appendectomy; Microbial reservoir; Infection PMID:22383922

Merchant, Rashida; Mower, William R.; Ourian, Ariel; Abrahamian, Fredrick M.; Moran, Gregory J.; Krishnadasan, Anusha; Talan, David A.

2012-01-01

393

SPECT and MRI analysis in Alzheimer's disease: relation to apolipoprotein E epsilon 4 allele.  

PubMed Central

OBJECTIVES--The epsilon 4 allele of apolipoprotein E (ApoE) is a risk factor for late onset Alzheimer's disease. ApoE is present in senile plaques, neurofibrillary tangles, and cerebrovascular amyloid, and it is implicated in synaptogenesis. The effect of ApoE polymorphism on the volumes of hippocampus, amygdala, and frontal lobe was studied. The hypothesis was that the patients with Alzheimer's disease carrying the epsilon 4 allele have more pronounced atrophy. The relation of ApoE and cerebral blood flow on cortical areas was also assessed. METHODS--Fifty eight patients with Alzheimer's disease at the early stage of the disease and 34 control subjects were studied. Patients with Alzheimer's disease were divided into subgroups according to the number of the epsilon 4 alleles. Volumes were measured by MRI and regional cerebral blood flow ratios referred to the cerebellum were examined by 99mTc-HMPAO SPECT. ApoE genotypes were determined by digestion of ApoE polymerase chain reaction products with the restriction enzyme Hha1. RESULTS--patients with Alzheimer's disease had smaller volumes of hippocampi and amygdala compared with control subjects, and the patients with Alzheimer's disease homozygous for the epsilon 4 allele had the most prominent volume loss in the medial temporal lobe structures. The frontal lobe volumes did not differ significantly. All patients with Alzheimer's disease had bilateral temporoparietal hypoperfusion and the subgroups with one or no epsilon 4 alleles also had frontal hypoperfusion compared with control subjects. The occipital perfusion ratios tended to decrease with increasing number of epsilon 4 alleles. CONCLUSIONS--Patients with Alzheimer's disease homozygous for the epsilon 4 allele seem to have severe damage in the medial temporal lobe structures early in the disease process and differ from the patients with Alzheimer's disease with one or no epsilon 4 alleles. PMID:8648331

Lehtovirta, M; Soininen, H; Laakso, M P; Partanen, K; Helisalmi, S; Mannermaa, A; Ryynanen, M; Kuikka, J; Hartikainen, P; Riekkinen, P J

1996-01-01

394

Differential Reduction Algorithms for the All-Order Epsilon Expansion of Hypergeometric Functions  

E-print Network

Hypergeometric functions provide a useful representation of Feynman diagrams occuring in precision phenomenology. In dimension regularization, the epsilon-expansion of these functions about d=4 is required. We discuss the current status of differential reduction algorithms. As an illustration, we consider the construction of the all-order epsilon-expansion of the Appell hypergeometric function about integer values of the parameters and present an explicit evaluations of the first few terms.

S. A. Yost; M. Yu. Kalmykov; B. F. L. Ward

2008-08-19

395

Towards A Full Orbital Solution For Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

Epsilon Aurigae is an eclipsing binary with a 27-year period that has baffled investigators for almost two centuries. The data from present and prior eclipses have strengthened our understanding of the system, but a comprehensive understanding of it's evolutionary state has remained illusive. There are presently two competing views: (1)the F-star primary is a supergiant of 15 Mo with a companion that is equally massive, yet obviously much smaller, that has yet to evolve off the MS or (2)the F-star is a post-AGB object of 4 Mo with a MS companion of 6-7 Mo that is enshrouded in an accretion disk of debris from the F-star. Deciding between the two models depends on having an accurate distance to the system. Published parallaxes all agree within their formal uncertainties, but have error bars larger than the nominal value. We have found that all astrometric results either neglected orbital motion or relied on orbital elements that are not congruent with spectroscopy (Stefanik et al. 2010) and with the recent in-eclipse interferometric observations (Kloppenborg et al. 2010). For example, all astrometric orbital solutions (van de Kamp 1978, Strand 1959, Heintz and Cantor 1994) assumed an eccentricity that does not agree with present value, e = 0.22-0.26 (Stefanik et al. 2010, Chadima et al. 2010), rather than solving for it. Likewise the HIPPARCOS parallax used Heintz's orbit that we argue is incorrect. We are deriving new orbital solutions for both components in the system. The solution for the F-star will use radial velocity and astrometric observations. The solution for the eclipsing object comes from the relative motion of the components implied by interferometric imaging. The University of Denver participants are grateful for support under NSF grant 10-16678 and the bequest of William Hershel Womble in support of astronomy at the University of Denver.

Kloppenborg, Brian K.; Hemenway, P.; Jensen, E.; Osborn, W.; Stencel, R.

2011-05-01

396

Role of the epsilon subunit of thermophilic F1-ATPase as a sensor for ATP.  

PubMed

The epsilon subunit of F(1)-ATPase from the thermophilic Bacillus PS3 (TF(1)) has been shown to bind ATP. The precise nature of the regulatory role of ATP binding to the epsilon subunit remains to be determined. To address this question, 11 mutants of the epsilon subunit were prepared, in which one of the basic or acidic residues was substituted with alanine. ATP binding to these mutants was tested by gel-filtration chromatography. Among them, four mutants that showed no ATP binding were selected and reconstituted with the alpha(3)beta(3)gamma complex of TF(1). The ATPase activity of the resulting alpha(3)beta(3)gammaepsilon complexes was measured, and the extent of inhibition by the mutant epsilon subunits was compared in each case. With one exception, weaker binding of ATP correlated with greater inhibition of ATPase activity. These results clearly indicate that ATP binding to the epsilon subunit plays a regulatory role and that ATP binding may stabilize the ATPase-active form of TF(1) by fixing the epsilon subunit into the folded conformation. PMID:17933866

Kato, Shigeyuki; Yoshida, Masasuke; Kato-Yamada, Yasuyuki

2007-12-28

397

Treatment of relapsing Clostridium difficile diarrhoea by administration of a non-toxigenic strain  

Microsoft Academic Search

Two patients with relapsingClostridium difficilediarrhoea following metronidazole and vancomycin therapy were colonised with a non-toxigenic avirulentClostridium difficilestrain given orally in three doses. Both patients appeared to respond without sideeffects. Oral bacteriotherapy with a defined nontoxigenic strain ofClostridium difficilewould appear to represent an acceptable, alternative and novel way to treat hospitalised patients who relapse withClostridium difficilediarrhoea after specific antibiotic therapy.

D. Seal; S. P. Borriello; F. Barclay; A. Welch; M. Piper; M. Bonnycastle

1987-01-01

398

Protein kinase C epsilon is localized to the Golgi via its zinc-finger domain and modulates Golgi function.  

PubMed Central

Protein kinase C (PKC) is a multigene family of serine/threonine kinases that are central to many signal transduction pathways. Among the PKC isozymes, only PKC epsilon has been reported to exhibit full oncogenic potential. PKC epsilon also displays unique substrate specificity and intracellular localization. To examine the interrelationship between the biological effects and domain structure of PKC epsilon, NIH 3T3 cells were stably transfected to overexpress different epitope-tagged fragments of PKC epsilon. The overexpressed proteins each contain the epsilon-tag peptide at the C terminus to allow ready detection with an antibody specific for the tag. The holo-PKC epsilon was found to localize with the Golgi network and other compartments, whereas the zinc-finger domain localized exclusively at the Golgi. Golgi-specific glycosaminoglycan sulfation was strongly inhibited in cells overexpressing either holo-PKC epsilon or its zinc-finger domain, while the secretion of sulfated glycosaminoglycans into the medium was impaired in cells expressing the PKC epsilon zinc-finger domain. Thus, these results suggest that PKC epsilon may be involved in specifically regulating Golgi-related processes. Further, the results indicate that PKC epsilon domains other than the kinase domain may also have biological activity and that the zinc-finger domain may function as a subcellular localization signal. Images Fig. 1 Fig. 2 Fig. 3 PMID:7877991

Lehel, C; Olah, Z; Jakab, G; Anderson, W B

1995-01-01

399

Cryptic Polyketide Synthase Genes in Non-Pathogenic Clostridium SPP  

PubMed Central

Modular type I polyketide synthases (PKS) produce a vast array of bacterial metabolites with highly diverse biological functions. Notably, all known polyketides were isolated from aerobic bacteria, and yet no example has been reported for strict anaerobes. In this study we explored the diversity and distribution of PKS genes in the genus Clostridium. In addition to comparative genomic analyses combined with predictions of modular type I polyketide synthase (PKS) gene clusters in sequenced genomes of Clostridium spp., a representative selection of other species inhabiting a variety of ecological niches was investigated by PCR screening for PKS genes. Our data reveal that all studied pathogenic Clostridium spp. are devoid of putative PKS genes. In stark contrast, cryptic PKS genes are widespread in genomes of non-pathogenic Clostridium species. According to phylogenetic analyses, the Clostridium PKS genes have unusual and diverse origins. However, reverse transcription quantitative PCR demonstrates that these genes are silent under standard cultivation conditions, explaining why the related metabolites have been overlooked until now. This study presents clostridia as a putative source for novel bioactive polyketides. PMID:22235310

Behnken, Swantje; Hertweck, Christian

2012-01-01

400

Rotor/Stator interactions of the epsilon subunit in Escherichia coli ATP synthase and implications for enzyme regulation.  

PubMed

The H(+)-translocating F(0)F(1)-ATP synthase of Escherichia coli functions as a rotary motor, coupling the transmembrane movement of protons through F(0) to the synthesis of ATP by F(1). Although the epsilon subunit appears to be tightly associated with the gamma subunit in the central stalk region of the rotor assembly, several studies suggest that the C-terminal domain of epsilon can undergo significant conformational change as part of a regulatory process. Here we use disulfide cross-linking of substituted cysteines on functionally coupled ATP synthase to characterize interactions of epsilon with an F(0) component of the rotor (subunit c) and with an F(1) component of the stator (subunit beta). Oxidation of the engineered F(0)F(1) causes formation of two disulfide bonds, betaD380C-S108C epsilon and epsilonE31C-cQ42C, to give a beta-epsilon-c cross-linked product in high yield. The results demonstrate the ability of epsilon to span the central stalk region from the surface of the membrane (epsilon-c) to the bottom of F(1) (beta-epsilon) and suggest that the conformation detected here is distinct from both the "closed" state seen with isolated epsilon (Uhlin, U., Cox, G. B., and Guss, J. M. (1997) Structure 5, 1219-1230) and the "open" state seen in a complex with a truncated form of the gamma subunit (Rodgers, A. J., and Wilce, M. C. (2000) Nat. Struct. Biol. 7, 1051-1054). The kinetics of beta-epsilon and epsilon-c cross-linking were studied separately using F(0)F(1) containing one or the other matched cysteine pair. The rate of cross-linking at the epsilon/c (rotor/rotor) interface is not influenced by the type of nucleotide added. In contrast, the rate of beta-epsilon cross-linking is fastest under ATP hydrolysis conditions, intermediate with MgADP, and slowest with MgAMP-PNP. This is consistent with a regulatory role for a reversible beta/epsilon (stator/rotor) interaction that blocks rotation and inhibits catalysis. Furthermore, the rate of beta-epsilon cross-linking is much faster than that indicated by previous studies, allowing for the possibility of a rapid response to regulatory signals. PMID:15199054

Bulygin, Vladimir V; Duncan, Thomas M; Cross, Richard L

2004-08-20

401

Phase Stability of Epsilon and Gamma Hniw (CL-20) at High-Pressure and Temperature  

NASA Astrophysics Data System (ADS)

Hexanitrohexaazaisowurtzitane (CL-20) is one of the few ingredients developed since World War II to be considered for transition to military use. Five polymorphs have been identified for CL-20 by FTIR measurements (?, ?, ?, ?, ?). As CL-20 is transitioned into munitions it will become necessary to predict its response under conditions of detonation, for performance evaluation. Such predictive modeling requires a phase diagram and basic thermodynamic properties of the various phases at high pressure and temperature. Therefore, the epsilon and gamma phases of CL-20 at static high-pressure and temperature were investigated using synchrotron angle-dispersive x-ray diffraction experiments. The samples were compressed and heated using diamond anvil cells (DAC). Pressures and temperatures achieved were around 5 GPa and 240 °C, respectively. The epsilon phase was stable to 6.3 GPa at ambient temperature. When heated at ambient pressure the epsilon phase was sustained to a temperature of 120 °C then und