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1

The International Reference Preparations of Clostridium welchii (C. perfringens) Beta and Epsilon Toxoids*  

PubMed Central

The Central Veterinary Laboratory, Weybridge, England was requested by the WHO Expert Committee on Biological Standardization to obtain suitable materials for international standards for Clostridium welchii (C. perfringens) beta and epsilon toxoids and to arrange collaborative assays. Preparations were obtained and dispensed as freeze-dried toxoids in ampoules. The toxoids were assayed by nine laboratories in eight countries. On the basis of the results obtained, the materials have been established as the International Reference Preparations of Clostridium welchii (C. perfringens) Beta and Epsilon Toxoids. PMID:215337

Davidson, I.; Gray, A. K.; Hebert, C. N.; Lesslie, I. W.

1978-01-01

2

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

3

Detection of Clostridium perfringens type D epsilon antitoxin in serum of goats by competitive and indirect ELISA  

Microsoft Academic Search

Indirect and competitive ELISA techniques were developed and their ability to detect antibodies to Clostridium perfringens epsilon toxin in goat serum was compared. Different dilutions of a hyperimmune goat serum, in serum from a colostrum-deprived kid, were used as positive controls, while sera from eleven colostrum-deprived kids were used as negative controls. The epsilon toxin antibodies in the hyperimmune serum

F. A. Uzal; K. Nielsen; W. R. Kelly

1997-01-01

4

Clostridium perfringens epsilon toxin: The third most potent bacterial toxin known.  

PubMed

Epsilon toxin (ETX) is produced by Clostridium perfringens type B and D strains and causes enterotoxemia, a highly lethal disease with major impacts on the farming of domestic ruminants, particularly sheep. ETX belongs to the aerolysin-like pore-forming toxin family. Although ETX has striking similarities to other toxins in this family, ETX is often more potent, with an LD50 of 100 ng/kg in mice. Due to this high potency, ETX is considered as a potential bioterrorism agent and has been classified as a category B biological agent by the Centers for Disease Control and Prevention (CDC) of the United States. The protoxin is converted to an active toxin through proteolytic cleavage performed by specific proteases. ETX is absorbed and acts locally in the intestines then subsequently binds to and causes lesions in other organs, including the kidneys, lungs and brain. The importance of this toxin for veterinary medicine and its possible use as a biological weapon have drawn the attention of researchers and have led to a large number of studies investigating ETX. The aim of the present work is to review the existing knowledge on ETX from C. perfringens type B and D. PMID:25234332

Alves, Guilherme Guerra; Machado de Ávila, Ricardo Andrez; Chávez-Olórtegui, Carlos Delfin; Lobato, Francisco Carlos Faria

2014-12-01

5

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

6

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

7

Epsilon toxin is essential for the virulence of Clostridium perfringens type D infection in sheep, goats, and mice.  

PubMed

Clostridium perfringens type D causes disease in sheep, goats, and other ruminants. Type D isolates produce, at minimum, alpha and epsilon (ETX) toxins, but some express up to five different toxins, raising questions about which toxins are necessary for the virulence of these bacteria. We evaluated the contribution of ETX to C. perfringens type D pathogenicity in an intraduodenal challenge model in sheep, goats, and mice using a virulent C. perfringens type D wild-type strain (WT), an isogenic ETX null mutant (etx mutant), and a strain where the etx mutation has been reversed (etx complemented). All sheep and goats, and most mice, challenged with the WT isolate developed acute clinical disease followed by death in most cases. Sheep developed various gross and/or histological changes that included edema of brain, lungs, and heart as well as hydropericardium. Goats developed various effects, including necrotizing colitis, pulmonary edema, and hydropericardium. No significant gross or histological abnormalities were observed in any mice infected with the WT strain. All sheep, goats, and mice challenged with the isogenic etx mutant remained clinically healthy for ?24 h, and no gross or histological abnormalities were observed in those animals. Complementation of etx knockout restored virulence; most goats, sheep, and mice receiving this complemented mutant developed clinical and pathological changes similar to those observed in WT-infected animals. These results indicate that ETX is necessary for type D isolates to induce disease, supporting a key role for this toxin in type D disease pathogenesis. PMID:23630957

Garcia, J P; Adams, V; Beingesser, J; Hughes, M L; Poon, R; Lyras, D; Hill, A; McClane, B A; Rood, J I; Uzal, F A

2013-07-01

8

Epsilon Toxin Is Essential for the Virulence of Clostridium perfringens Type D Infection in Sheep, Goats, and Mice  

PubMed Central

Clostridium perfringens type D causes disease in sheep, goats, and other ruminants. Type D isolates produce, at minimum, alpha and epsilon (ETX) toxins, but some express up to five different toxins, raising questions about which toxins are necessary for the virulence of these bacteria. We evaluated the contribution of ETX to C. perfringens type D pathogenicity in an intraduodenal challenge model in sheep, goats, and mice using a virulent C. perfringens type D wild-type strain (WT), an isogenic ETX null mutant (etx mutant), and a strain where the etx mutation has been reversed (etx complemented). All sheep and goats, and most mice, challenged with the WT isolate developed acute clinical disease followed by death in most cases. Sheep developed various gross and/or histological changes that included edema of brain, lungs, and heart as well as hydropericardium. Goats developed various effects, including necrotizing colitis, pulmonary edema, and hydropericardium. No significant gross or histological abnormalities were observed in any mice infected with the WT strain. All sheep, goats, and mice challenged with the isogenic etx mutant remained clinically healthy for ?24 h, and no gross or histological abnormalities were observed in those animals. Complementation of etx knockout restored virulence; most goats, sheep, and mice receiving this complemented mutant developed clinical and pathological changes similar to those observed in WT-infected animals. These results indicate that ETX is necessary for type D isolates to induce disease, supporting a key role for this toxin in type D disease pathogenesis. PMID:23630957

Garcia, J. P.; Adams, V.; Beingesser, J.; Hughes, M. L.; Poon, R.; Lyras, D.; Hill, A.; McClane, B. A.; Rood, J. I.

2013-01-01

9

Recombinant expression of in silico identified Bcell epitope of epsilon toxin of Clostridium perfringens in translational fusion with a carrier protein  

PubMed Central

Epsilon toxin secreted by Clostridium perfringens types B and D has been directly implicated as the causative agent of fatal enterotoxemia in domestic animals. The aim of the present study is to use in silico approach for identification of B-cell epitope(s) of epsilon toxin, and its expression in fusion with a carrier protein to analyze its potential as vaccine candidate(s). Using different computational analyses and bioinformatics tools, a number of antigenic determinant regions of epsilon toxin were identified. One of the B cell epitopes of epsilon toxin comprising the region (amino acids 40-62) was identified as a promising antigenic determinant. This Etx epitope (Etx40-62) was cloned and expressed as a translational fusion with B-subunit of heat labile enterotoxin (LTB) of E. coli in a secretory expression system. Similar to the native LTB, the recombinant fusion protein retained the ability to pentamerize and bind to GM1 ganglioside receptor of LTB. The rLTB.Etx40-62 could be detected both with anti-Etx and anti-LTB antisera. The rLTB.Etx40-62 fusion protein thus can be evaluated as a potential vaccine candidate against C. perfringens. Abbreviations aa - amino acid(s), Etx - epsilon toxin of Clostridium perfringens, LTB - B-subunit of heat labile enterotoxin of E. coli. PMID:23904738

Kaushik, Himani; Deshmukh, Sachin; Mathur, Deepika Dayal; Tiwari, Archana; Garg, Lalit C

2013-01-01

10

Clostridium perfringens Epsilon Toxin Targets Granule Cells in the Mouse Cerebellum and Stimulates Glutamate Release  

PubMed Central

Epsilon toxin (ET) produced by C. perfringens types B and D is a highly potent pore-forming toxin. ET-intoxicated animals express severe neurological disorders that are thought to result from the formation of vasogenic brain edemas and indirect neuronal excitotoxicity. The cerebellum is a predilection site for ET damage. ET has been proposed to bind to glial cells such as astrocytes and oligodendrocytes. However, the possibility that ET binds and attacks the neurons remains an open question. Using specific anti-ET mouse polyclonal antibodies and mouse brain slices preincubated with ET, we found that several brain structures were labeled, the cerebellum being a prominent one. In cerebellar slices, we analyzed the co-staining of ET with specific cell markers, and found that ET binds to the cell body of granule cells, oligodendrocytes, but not astrocytes or nerve endings. Identification of granule cells as neuronal ET targets was confirmed by the observation that ET induced intracellular Ca2+ rises and glutamate release in primary cultures of granule cells. In cultured cerebellar slices, whole cell patch-clamp recordings of synaptic currents in Purkinje cells revealed that ET greatly stimulates both spontaneous excitatory and inhibitory activities. However, pharmacological dissection of these effects indicated that they were only a result of an increased granule cell firing activity and did not involve a direct action of the toxin on glutamatergic nerve terminals or inhibitory interneurons. Patch-clamp recordings of granule cell somata showed that ET causes a decrease in neuronal membrane resistance associated with pore-opening and depolarization of the neuronal membrane, which subsequently lead to the firing of the neuronal network and stimulation of glutamate release. This work demonstrates that a subset of neurons can be directly targeted by ET, suggesting that part of ET-induced neuronal damage observed in neuronal tissue is due to a direct effect of ET on neurons. PMID:20941361

Lonchamp, Etienne; Dupont, Jean-Luc; Wioland, Laetitia; Courjaret, Raphaël; Mbebi-Liegeois, Corinne; Jover, Emmanuel; Doussau, Frédéric; Popoff, Michel R.; Bossu, Jean-Louis; de Barry, Jean; Poulain, Bernard

2010-01-01

11

Interaction of Clostridium perfringens epsilon-toxin with biological and model membranes: A putative protein receptor in cells.  

PubMed

Epsilon-toxin (ETX) is a powerful toxin produced by some strains of Clostridium perfringens (classified as types B and D) that is responsible for enterotoxemia in animals. ETX forms pores through the plasma membrane of eukaryotic cells, consisting of a ?-barrel of 14 amphipathic ?-strands. ETX shows a high specificity for certain cell lines, of which Madin-Darby canine kidney (MDCK) is the first sensitive cell line identified and the most studied one. The aim of this study was to establish the role of lipids in the toxicity caused by ETX and the correlation of its activity in model and biological membranes. In MDCK cells, using cell counting and confocal microscopy, we have observed that the toxin causes cell death mediated by toxin binding to plasma membrane. Moreover, ETX binds and permeabilizes the membranes of giant plasma membrane vesicles (GPMV). However, little effect is observed on protein-free vesicles. The data suggest the essential role of a protein receptor for the toxin in cell membranes. PMID:25485476

Manni, Marco M; Sot, Jesús; Goñi, Félix M

2015-03-01

12

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, Sérgio P.; Savva, Christos G.; Naylor, Claire E.; Cole, Ambrose R.; Basak, Ajit K.; Moss, David S.; Titball, Richard W.

2014-01-01

13

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-Arévalo, Jonatan; Pauillac, Serge; Díaz-Hidalgo, Laura; Martín-Satué, Mireia; Popoff, Michel R.; Blasi, Juan

2014-01-01

14

Clostridium perfringens urease genes are plasmid borne.  

PubMed Central

Although many bacteria are ureolytic, and in some cases urease acts as a virulence factor, the urease phenotype has not been analyzed in the anaerobic pathogen Clostridium perfringens. In this study, approximately 2% of C. perfringens strains, representing the principal biotypes, were found to harbor the urease structural genes, ureABC, and these were localized on large plasmids that often encode, in addition, the lethal epsilon or iota toxins or the enterotoxin. This represents the first report of a plasmid-encoded urease in a gram-positive bacterium. The C. perfringens enzyme was highly similar to the ureases of other bacteria and cross-reacted with antibodies raised against the urease purified from Helicobacter pylori. Urease production was inhibited by urea and induced under growth conditions where the availability of nitrogen sources was limiting. To date, this form of regulation has been observed only for chromosomal ureABC genes. PMID:9169769

Dupuy, B; Daube, G; Popoff, M R; Cole, S T

1997-01-01

15

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

16

The enteric toxins of Clostridium perfringens  

Microsoft Academic Search

The Gram-positive pathogen Clostridium perfringens is a major cause of human and veterinary enteric disease largely because this bacterium can produce several toxins when present inside the gastrointestinal tract. The enteric toxins of C. perfringens share two common features: (1) they are all single polypeptides of modest (~25–35 kDa) size, although lacking in sequence homology, and (2) they generally act by

J. G. Smedley III; D. J. Fisher; S. Sayeed; G. Chakrabarti; B. A. McClane

2004-01-01

17

The enteric toxins of Clostridium perfringens  

Microsoft Academic Search

The Gram-positive pathogenClostridium perfringens is a major cause of human and veterinary enteric disease largely because this bacterium can produce several toxins when present\\u000a inside the gastrointestinal tract. The enteric toxins of C. perfringens share two common features: (1) they are all single polypeptides of modest (~25—35 kDa) size, although lacking in sequence\\u000a homology, and (2) they generally act by

J. G. Smedley; D. J. Fisher; S. Sayeed; G. Chakrabarti; B. A. McClane

18

Enterotoxin Plasmid from Clostridium perfringens Is Conjugative  

Microsoft Academic Search

Clostridium perfringens enterotoxin is the major virulence factor involved in the pathogenesis of C. perfringens type A food poisoning and several non-food-borne human gastrointestinal illnesses. The enterotoxin gene, cpe, is located on the chromosome of food-poisoning isolates but is found on a large plasmid in non-food-borne gastrointestinal disease isolates and in veterinary isolates. To evaluate whether the cpe plasmid encodes

SIGRID BRYNESTAD; MAHFUZUR R. SARKER; BRUCE A. MCCLANE; PER EINAR GRANUM; JULIAN I. ROOD

2001-01-01

19

Diagnosis of Clostridium perfringens intestinal infections in sheep and goats.  

PubMed

Clostridium perfringens produces disease in sheep, goats and other animal species, most of which are generically called enterotoxemias. This micro-organism can be a normal inhabitant of the intestine of most animal species including humans, but when the intestinal environment is altered by sudden changes in diet or other factors, C. perfringens proliferates in large numbers and produces several potent toxins that are absorbed into the general circulation or act locally with usually devastating effects on the host. History, clinical signs and gross post-mortem findings are useful tools for establishing a presumptive diagnosis of enterotoxaemia by C. perfringens in sheep and goats, although no definitive diagnosis of these diseases can be made without laboratory confirmation. Because all types of C. perfringens can be normal inhabitants of the intestine of most animals, culture of this micro-organism from intestinal contents of animals has no diagnostic value unless a colony count is performed and large numbers (usually more than 10(4)-10(7)CFU/g) of C. perfringens are found. The most accepted criterion in establishing a definitive diagnosis of enterotoxaemia by C. perfringens is the detection of its toxins in intestinal contents. However, some of the major toxins of C. perfringens (i.e. epsilon toxin) can also be found, albeit in small amounts, in the small intestine of clinically normal sheep, and this poses a diagnostic challenge. In such cases the histopathology of the brain must be used as an alternative diagnostic tool, since the lesions produced by epsilon toxin in the brains of sheep and goats are unique and pathognomonic for C. perfringens type D enterotoxaemia. Ancillary tests, such as measurement of urine glucose or observation of Gram stained smears of intestinal mucosa can be used and, although they have a presumptive diagnostic value when positive, they cannot be used to rule out a diagnosis of enterotoxaemia if they are negative. In conclusion, the diagnosis of C. perfringens infections in animals is complex and it is appropriate to rely on a combination of diagnostic techniques rather than one singe test. PMID:16701510

Uzal, F A

2004-04-01

20

Clostridium perfringens in Meat and Meat Products  

PubMed Central

A total of 262 specimens of meat and meat dishes were examined for the presence of Clostridium perfringens. Of this total, 161 were raw, unprocessed beef, veal, lamb, pork, or chicken; 101 were processed meats and meat dishes. C. perfringens was isolated from 113 (43.1%) of these specimens. The highest percentage of contamination (82%) was found in veal cuts, and the lowest (4.7%) in sliced sandwich meats and spreads. Only 2 of the 113 isolates were shown to produce heat-resistant spores, which indicates a very low incidence (0.8%) of contamination. These findings indicate that outbreaks of C. perfringens food-borne disease in the Cincinnati area are caused principally by the contamination of the food with vegetative cells or spores of the organism after cooking. Studies of the effects of various holding temperatures on the growth of C. perfringens indicated that, in the range of 5 to 15 C, no multiplication would occur, but that viable cells would still be present at the end of a 5-day holding period. Extremely rapid growth occurred at temperatures around 45 C, and complete inhibition of growth was accomplished between 49 and 52 C. PMID:14325274

Hall, Herbert E.; Angelotti, Robert

1965-01-01

21

Diagnosis of Clostridium perfringens intestinal infections in sheep and goats  

Microsoft Academic Search

Clostridium perfringens produces disease in sheep, goats and other animal species, most of which are generically called enterotoxemias. This micro-organism can be a normal inhabitant of the intestine of most animal species including humans, but when the intestinal environment is altered by sudden changes in diet or other factors, C. perfringens proliferates in large numbers and produces several potent toxins

F. A. Uzal

2004-01-01

22

Towards an understanding of the role of Clostridium perfringens toxins in human and animal disease  

PubMed Central

Clostridium perfringens uses its arsenal of >16 toxins to cause histotoxic and intestinal infections in humans and animals. It has been unclear why this bacterium produces so many different toxins, especially since many target the plasma membrane of host cells. However, it is now established that C. perfringens uses chromosomally encoded alpha toxin (a phospholipase C) and perfringolysin O (a pore-forming toxin) during histotoxic infections. In contrast, this bacterium causes intestinal disease by employing toxins encoded by mobile genetic elements, including C. perfringens enterotoxin, necrotic enteritis toxin B-like, epsilon toxin and beta toxin. Like perfringolysin O, the toxins with established roles in intestinal disease form membrane pores. However, the intestinal disease-associated toxins vary in their target specificity, when they are produced (sporulation vs vegetative growth), and in their sensitivity to intestinal proteases. Producing many toxins with diverse characteristics likely imparts virulence flexibility to C. perfringens so it can cause an array of diseases. PMID:24762309

Uzal, Francisco A; Freedman, John C; Shrestha, Archana; Theoret, James R; Garcia, Jorge; Awad, Milena M; Adams, Vicki; Moore, Robert J; Rood, Julian I; McClane, Bruce A

2014-01-01

23

Characterization of Clostridium perfringens in the feces of adult horses and foals with acute enterocolitis  

PubMed Central

Up to 60% of cases of equine colitis have no known cause. To improve understanding of the causes of acute colitis in horses, we hypothesized that Clostridium perfringens producing enterotoxin (CPE) and/or beta2 toxin (CPB2) are common and important causes of severe colitis in horses and/or that C. perfringens producing an as-yet-undescribed cytotoxin may also cause colitis in horses. Fecal samples from 55 horses (43 adults, 12 foals) with clinical evidence of colitis were evaluated by culture for the presence of Clostridium difficile, C. perfringens, and Salmonella. Feces were also examined by enzyme-linked immunosorbent assay (ELISA) for C. difficile A/B toxins and C. perfringens alpha toxin (CPA), beta2 toxin (CPB2), and enterotoxin (CPE). Five C. perfringens isolates per sample were genotyped for the following genes: cpa, cpb, cpb2 consensus, cpb2 atypical, cpe (enterotoxin), etx (epsilon toxin), itx (iota toxin), netB (necrotic enteritis toxin B), and tpeL (large C. perfringens cytotoxin). The supernatants of these isolates were also evaluated for toxicity for an equine cell line. All fecal samples were negative for Salmonella. Clostridium perfringens and C. difficile were isolated from 40% and 5.4% of samples, respectively. All fecal samples were negative for CPE. Clostridium perfringens CPA and CPB2 toxins were detected in 14.5% and 7.2% of fecal samples, respectively, all of which were culture-positive for C. perfringens. No isolates were cpe, etx, netB, or tpeL gene-positive. Atypical cpb2 and consensus cpb2 genes were identified in 15 (13.6%) and 4 (3.6%) of 110 isolates, respectively. All equine C. perfringens isolates showed far milder cytotoxicity effects than a CPB-producing positive control, although cpb2-positive isolates were slightly but significantly more cytotoxic than negative isolates. Based on this studied population, we were unable to confirm our hypothesis that CPE and CPB2-producing C. perfringens are common in horses with colitis in Ontario and we failed to identify cytotoxic activity in vitro in the type A isolates recovered. PMID:24396174

Gohari, Iman Mehdizadeh; Arroyo, Luis; MacInnes, Janet I.; Timoney, John F.; Parreira, Valeria R.; Prescott, John F.

2014-01-01

24

Characterization of Clostridium perfringens in the feces of adult horses and foals with acute enterocolitis.  

PubMed

Up to 60% of cases of equine colitis have no known cause. To improve understanding of the causes of acute colitis in horses, we hypothesized that Clostridium perfringens producing enterotoxin (CPE) and/or beta2 toxin (CPB2) are common and important causes of severe colitis in horses and/or that C. perfringens producing an as-yet-undescribed cytotoxin may also cause colitis in horses. Fecal samples from 55 horses (43 adults, 12 foals) with clinical evidence of colitis were evaluated by culture for the presence of Clostridium difficile, C. perfringens, and Salmonella. Feces were also examined by enzyme-linked immunosorbent assay (ELISA) for C. difficile A/B toxins and C. perfringens alpha toxin (CPA), beta2 toxin (CPB2), and enterotoxin (CPE). Five C. perfringens isolates per sample were genotyped for the following genes: cpa, cpb, cpb2 consensus, cpb2 atypical, cpe (enterotoxin), etx (epsilon toxin), itx (iota toxin), netB (necrotic enteritis toxin B), and tpeL (large C. perfringens cytotoxin). The supernatants of these isolates were also evaluated for toxicity for an equine cell line. All fecal samples were negative for Salmonella. Clostridium perfringens and C. difficile were isolated from 40% and 5.4% of samples, respectively. All fecal samples were negative for CPE. Clostridium perfringens CPA and CPB2 toxins were detected in 14.5% and 7.2% of fecal samples, respectively, all of which were culture-positive for C. perfringens. No isolates were cpe, etx, netB, or tpeL gene-positive. Atypical cpb2 and consensus cpb2 genes were identified in 15 (13.6%) and 4 (3.6%) of 110 isolates, respectively. All equine C. perfringens isolates showed far milder cytotoxicity effects than a CPB-producing positive control, although cpb2-positive isolates were slightly but significantly more cytotoxic than negative isolates. Based on this studied population, we were unable to confirm our hypothesis that CPE and CPB2-producing C. perfringens are common in horses with colitis in Ontario and we failed to identify cytotoxic activity in vitro in the type A isolates recovered. PMID:24396174

Gohari, Iman Mehdizadeh; Arroyo, Luis; Macinnes, Janet I; Timoney, John F; Parreira, Valeria R; Prescott, John F

2014-01-01

25

Clostridium perfringens Alpha-toxin Recognizes the GM1a-TrkA Complex*S  

E-print Network

and sphingomy- elin are important virulence factors in the pathogenesis of diseases caused by Listeria monocytogenes, Pseudomonas aeruginosa, and several Clostridium spp. (3­5). Clostridium perfringens

Gleeson, Joseph G.

26

Distribution of Clostridium perfringens isolates from piglets in South Korea.  

PubMed

Clostridium perfringens causes various digestive system disease symptoms in pigs. In the present study, 11 C. perfringens isolates were obtained from diarrheic piglets and 18 from healthy piglets. All of the C. perfringens isolates were shown to be type A using a multiplex PCR assay. The ?2 toxin gene was detected in 27/29 C. perfringens isolates, i.e., 81% (9/11) of diarrheic piglets and 100% (18/18) of healthy piglets, and all of the genes had the same sequence. In conclusion, the ?2 toxin gene of C. perfringens was distributed widely in Korean piglets regardless of the incidence of diarrhea, and there was no clear relationship with enteric disease. A pulsed-field gel electrophoresis analysis of DNA digested using SmaI demonstrated the non-clonal spread of C. perfringens isolates from piglets. PMID:24430655

Lee, Ki-Eun; Lim, Seong-In; Shin, Seong-Ho; Kwon, Yong-Kuk; Kim, Ha-Young; Song, Jae-Young; An, Dong-Jun

2014-05-01

27

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

28

MATHEMATICAL MODELING OF GROWTH OF CLOSTRIDIUM PERFRINGENS IN COOKED BEEF  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this work was to study the growth kinetics of Clostridium perfringens spores in thermally processed ground beef and compare the suitability of the Gompertz, logistic, and Baranyi models used to describe the isothermal bacterial growth. Ground beef samples inoculated with the spores ...

29

Tips to Prevent Illness from Clostridium Perfringens  

MedlinePLUS

... is one of the most common causes of food poisoning in the United States. Learn more on ways ... 1 million cases of foodborne illness (sometimes called "food poisoning") each year. C. perfringens is found in many ...

30

Typing of Clostridium perfringens by in vitro amplification of toxin genes.  

PubMed

The strains of Clostridium perfringens are classified according to major toxins produced. Classically, this determination involves the seroneutralization of their lethal effect in mice. However, this method requires specific antisera and a large number of mice. In this work, a new typing method was developed based on the amplification of toxin genes by polymerase chain reaction (PCR). By combination of several pairs of primers, the toxinotype of a Cl. perfringens strain was determined by looking at the pattern of bands on an agarose gel electrophoresis. This mixture contained primers amplifying simultaneously a part of alpha-toxin, beta-toxin, epsilon-toxin and enterotoxin genes. In order to distinguish between toxinotype A and E, the l-toxin gene fragment must be amplified in a separate PCR reaction. Moreover, with the primers combination, in most cases, a PCR product corresponding to the alpha-toxin gene was obtained from direct enrichments of animal intestinal contents. PMID:7822224

Daube, G; China, B; Simon, P; Hvala, K; Mainil, J

1994-12-01

31

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

32

Hazard analysis of Clostridium perfringens in the Skylab Food System  

NASA Technical Reports Server (NTRS)

The Skylab Food System presented unique microbiological problems because food was warmed in null-gravity and because the heat source was limited to 69.4 C (to prevent boiling in null-gravity). For these reasons, the foods were manufactured using critical control point techniques of quality control coupled with appropriate hazard analyses. One of these hazard analyses evaluated the threat from Clostridium perfringens. Samples of food were inoculated with C. perfringens and incubated for 2 h at temperatures ranging from 25 to 55 C. Generation times were determined for the foods at various temperatures. Results of these tests were evaluated taking into consideration: food-borne disease epidemiology, the Skylab food manufacturing procedures, and the performance requirements of the Skylab Food System. Based on this hazard analysis, a limit for C. perfringens of 100/g was established for Skylab foods.

Bourland, C. T.; Huber, C. S.; Kiser, P. R.; Heidelbaugh, N. D.; Rowley, D. B.

1974-01-01

33

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

34

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

Microsoft Academic Search

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.

Anders Johansson; Anna Aspan; Elisabeth Bagge; Viveca Båverud; Björn E Engström; Karl-Erik Johansson

2006-01-01

35

Molecular methods for the analysis of Clostridium perfringens relevant to food hygiene  

Microsoft Academic Search

Clostridium perfringens continues to be a common cause of food-borne disease [1,2]. It produces an enterotoxin (CPE) which is released upon lysis of the vegetative cell during sporulation in the intestinal tract. Catering premises with insufficient cooling and reheating devices often seem to be the cause of outbreaks of C. perfringens food poisoning. Typing of C. perfringens is of great

Barbara Schalch; Brigitte Sperner; Hartmut Eisgruber; Andreas Stolle

1999-01-01

36

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

37

Crystallization and preliminary crystallographic analysis of the Clostridium perfringens enterotoxin.  

PubMed

Clostridium perfringens is a Gram-positive anaerobic species of bacterium that is notable for its ability to produce a plethora of toxins, including membrane-active toxins (alpha-toxins), pore-forming toxins (-toxins) and binary toxins (iota-toxins). Here, the crystallization of the full-length wild-type C. perfringens enterotoxin is reported, which is the causative agent of the second most prevalent food-borne illness in the United States and has been implicated in many other gastrointestinal pathologies. Several crystal forms were obtained. However, only two of these optimized crystal forms (I and II) were useable for X-ray diffraction data collection. The form I crystals diffracted to d(min) = 2.7 A and belonged to space group C2, while the form II crystals diffracted to d(min) = 4 A and belonged to space group P2(1)3. PMID:20606275

Briggs, David C; Smedley, James G; McClane, Bruce A; Basak, Ajit K

2010-07-01

38

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

39

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

40

Host cell-induced signaling causes Clostridium perfringens to upregulate production of toxins important for intestinal infections  

PubMed Central

Clostridium perfringens causes enteritis and enterotoxemia in humans and livestock due to prolific toxin production. In broth culture, C. perfringens uses the Agr-like quorum sensing (QS) system to regulate production of toxins important for enteritis/enterotoxemia, including beta toxin (CPB), enterotoxin, and epsilon toxin (ETX). The VirS/VirR two-component regulatory system (TCRS) also controls CPB production in broth cultures. Both the Agr-like QS and VirS/VirR systems are important when C. perfringens senses enterocyte-like Caco-2 cells and responds by upregulating CPB production; however, only the Agr-like QS system is needed for host cell-induced ETX production. These in vitro observations have pathophysiologic relevance since both the VirS/VirR and Agr-like QS signaling systems are required for C. perfringens strain CN3685 to produce CPB in vivo and to cause enteritis or enterotoxemia. Thus, apparently upon sensing its presence in the intestines, C. perfringens utilizes QS and TCRS signaling to produce toxins necessary for intestinal virulence. PMID:24061146

Chen, Jianming; Ma, Menglin; Uzal, Francisco A; McClane, Bruce A

2014-01-01

41

Potential for growth of Clostridium perfringens from spores in pork scrapple during cooling  

Technology Transfer Automated Retrieval System (TEKTRAN)

We conducted stabilization studies to determine the ability of Clostridium perfringens spores to germinate and grow during exponential cooling of a commercial formulation of pork scrapple. Scrapple was inoculated with a mixture of three strains of C. perfringens spores (NTCC 8238, NCTC 8239, and AT...

42

Meningoencephalitis with Subdural Empyema Caused by Toxigenic Clostridium perfringens Type A  

PubMed Central

We report a clinical case of meningoencephalitis with subdural empyema in an immunocompromised farmer caused by toxigenic Clostridium perfringens type A, which was identified by 16S RNA gene analysis of cerebrospinal fluid and subdural empyema. In immunocompromised patients, C. perfringens should be considered a potential pathogen of sepsis. PMID:22895036

Achermann, Yvonne; Kovari, Helen; Dent, Wolfgang; Hombach, Michael; Bloemberg, Guido

2012-01-01

43

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

44

EFFECT OF OZONE STRESS ON CLOSTRIDIUM PERFRINGENS VIABILITY FOLLOWING THE AQUEOUS TREATMENT OF BEEF SURFACES  

Technology Transfer Automated Retrieval System (TEKTRAN)

The antimicrobial efficacy of ozone on the food-borne pathogen, Clostridium perfringens, was evaluated on London Broil top round cut beef surfaces using an aqueous wash system. Current food processing methods do not assure elimination of spores of C. perfringens, thus there is a high likelihood of ...

45

Molecular typing and epidemiological survey of prevalence of Clostridium perfringens types by multiplex PCR.  

PubMed Central

Clostridium perfringens has been classified into five toxigenic types (A through E) on the basis of its capability to produce major lethal toxins (alpha, beta, epsilon, and iota toxins). Seroneutralization with mice or guinea pigs has been used to type each toxin, but this conventional method has some disadvantages. Therefore, we used a molecular biological technique to type the bacterium in the present study. A multiplex PCR was developed for this purpose. This method has several advantages in comparison with seroneutralization with mice or guinea pigs. By this method, we also investigated the most prevalent type(s) of the organism in Korean calves, piglets, and chickens showing clinical symptoms such as diarrhea, enterotoxemia, and necrotic enteritis. Only type A was isolated from calves and chickens, while type C (2 of 14 isolates), in addition to type A, was isolated from piglets. These results suggested that seroneutralization could be replaced by our new method and that type A of C. perfringens is the most prevalent type in livestock in Korea. PMID:8968913

Yoo, H S; Lee, S U; Park, K Y; Park, Y H

1997-01-01

46

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

47

Clostridium perfringens Antigens Recognized by Broiler Chickens Immune to Necrotic Enteritis?  

PubMed Central

Little is known about immunity to necrotic enteritis (NE) in chickens. A recent study of broiler chickens showed that protection against NE was associated with infection-immunization with virulent but not with avirulent Clostridium perfringens.In the current study, six secreted antigenic proteins unique to virulent C. perfringens that reacted to serum antibodies from immune birds were identified by mass spectrophotometry; three of these proteins are part of the VirR-VirS regulon. PMID:17065258

Kulkarni, R. R.; Parreira, V. R.; Sharif, S.; Prescott, J. F.

2006-01-01

48

Antimicrobial susceptibility of Clostridium perfringens isolated from piglets with or without diarrhea in Brazil  

PubMed Central

The minimum inhibitory concentration (MIC) was determined for 13 antibiotics against Clostridium perfringens isolated from Brazilian piglets. The collection of isolates was performed in June to October 2010. All isolates were susceptible to amoxicillin and ceftiofur, whereas most were resistant to tetracycline and lincomycin. Avilamycin and narasin were more effective against isolates from non-diarrheic than from diarrheic piglets. The other antimicrobials were less active in need of high concentrations to inhibit the growth of the C. perfringens type A. These results suggest the need for further studies evaluating molecular factors related to the antimicrobial resistance of C. perfringens. PMID:24031924

Salvarani, Felipe Masiero; Silveira Silva, Rodrigo Otávio; Pires, Prhiscylla Sadanã; da Costa Cruz Júnior, Eduardo Coulaud; Albefaro, Isabella Silva; de Carvalho Guedes, Roberto Maurício; Faria Lobato, Francisco Carlos

2012-01-01

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

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

51

ESTIMATATION OF GROWTH OF CLOSTRIDIUM PERFRINGENS IN COOKED BEEF UNDER FLUCTUATING TEMPERATURE CONDITIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new concept for estimating the bacterial growth under temperature fluctuations was hypothesized and validated using Clostridium perfringens as a test organism. This new methodology was based on the Gompertz models to calculate the equivalent growth times under different temperatures, and estimate...

52

INHIBITION OF QUORUM SENSING IN CLOSTRIDIUM PERFRINGENS AS A MEANS TOWARD FOOD SAFETY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cell density-dependent signaling through the use of autoinducers, classified as quorum sensing, may play a role in the survival and virulence of Clostridium perfringens in foods. The natural 2-(5H)-furanone, ascorbic acid (vitamin C), was chosen for evaluation as a quorum sensing analogue due to it...

53

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

54

Evaluation of Clostridium perfringens as a tracer of sewage contamination in sediments by two enumeration methods.  

PubMed

A traditional method of enumerating Clostridium perfringens using membrane filtration (MF) as an indicator of fecal contamination was compared to recently developed rapid method using Rapid Fung Double Tube (RFDT) in an evaluation to characterize the extent of sewage contamination in sediments of the Great Lakes. Evaluation of these two methods included determining C. perfringens concentrations and recovery efficiencies from sewage, sewage-spiked sediments, and water (surface and bottom) and sediment samples collected from two Great Lakes. The RFDT method proved to be a superior method for identifying C. perfringens in lake sediments compared to MF, as it had higher recovery efficiency and was more rapid, reliable, simple, and effective. This study provides biological evidence of the long-term deposition and movement of sewage particulates in the Great Lakes environment and demonstrates the potential usefulness of C. perfringens as a tracer for sewage contamination using a reliable enumeration method. PMID:24833022

Vijayavel, K; Kashian, D R

2014-09-01

55

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

56

Genotyping of Enterotoxigenic Clostridium perfringens Fecal Isolates Associated with Antibiotic-Associated Diarrhea and Food Poisoning in North America  

Microsoft Academic Search

Clostridium perfringens type A isolates producing enterotoxin (CPE) are an important cause of food poisoning and non-food-borne human gastrointestinal (GI) diseases, including antibiotic-associated diarrhea (AAD). Recent studies suggest that C. perfringens type A food poisoning is caused by C. perfringens isolates carrying a chromosomal cpe gene, while CPE-associated non-food-borne GI diseases, such as AAD, are caused by plasmid cpe isolates.

SHAUNA G. SPARKS; ROBERT J. CARMAN; MAHFUZUR R. SARKER

2001-01-01

57

The molecular-genetic analysis of Clostridium perfringens strains isolated from broilers on farms in Central Russia  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of the research was to perform phenotypic and molecular-genetic typing of Clostridium perfringens strains commonly spread on poultry farms in Central Russia. Samples of homogenized iliac and cecal contents from 760 broilers were assayed and 325 C. perfringens strains (42.8 %) were isol...

58

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

Microsoft Academic Search

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

Alex Yeow-Lim Teo; Hai-Meng Tan

2005-01-01

59

Inè uence of Several Methodological Factors on the Growth of Clostridium perfringens in Cooling Rate Challenge Studies  

Microsoft Academic Search

Proper temperature control is essential in preventing Clostridium perfringens food poisoning. The U.S. Department of Agriculture Food Safety and Inspection Service cooling guidelines offer two options for the cooling of meat products: follow a standard time-temperature schedule or validate that alternative cooling regimens result in no more than a 1-log CFU\\/g increase of C. perfringens and no growth of Clostridium

SARAH SMITH; VIJAY JUNEJA; DONALD W. SCHAFFNER

60

Toxinotyping of Clostridium perfringens fecal isolates of reintroduced Père David's deer (Elaphurus davidianus) in China.  

PubMed

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

61

Residues involved in the pore-forming activity of the Clostridium perfringens iota toxin.  

PubMed

Clostridium perfringens iota toxin is a binary toxin that is organized into enzyme (Ia) and binding (Ib) components. Ib forms channels in lipid bilayers and mediates the transport of Ia into the target cells. Here we show that Ib residues 334-359 contain a conserved pattern of alternating hydrophobic and hydrophilic residues forming two amphipathic ?-strands involved in membrane insertion and channel formation. This stretch of amino acids shows remarkable structural and functional analogies with the ?-pore-forming domain of C.?perfringens epsilon toxin. Several mutations within the two amphipathic ?-strands affected pore formation, single-channel conductance and ion selectivity (S339E-S341E, Q345H N346E) confirming their involvement in channel formation. F454 of Ib corresponds to the ?-clamp F427 of anthrax protective antigen and F428 of C2II binary toxins. The mutation F454A resulted in a loss of cytotoxicity and strong increase in single-channel conductance (500?pS as compared with 85?pS in 1?M KCl) with a slight decrease in cation selectivity, indicating that the ?-clamp is highly conserved and crucial for binary toxin activity. In contrast, the mutants Q367D, N430D, L443E had no or only minor effects on Ib properties, while T360I, T360A and T360W caused a dramatic effect on ion selectivity and single-channel conductance, indicating gross disturbance of the oligomer structure. This suggests that, at least in the iota toxin family, T360 has a structural role in the pore organization. Moreover, introduction of charged residues within the channel (S339E-S341E) or in the vestibule (Q367D, N430D and L443E) had virtually no effect on chloroquine or Ia binding, whereas F454A, T360I, T360A and T360W strongly decreased the chloroquine and Ia affinity to Ib. These results support that distinct residues within the vestibule interact with chloroquine and Ia or are responsible for channel structure, while the channel lining amino acids play a less important role. PMID:25266274

Knapp, Oliver; Maier, Elke; Waltenberger, Eva; Mazuet, Christelle; Benz, Roland; Popoff, Michel R

2015-02-01

62

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

E-print Network

THE INDUCTION OF TOXIN NEUTRALIZING ANTIBODIES TO CLOSTRIDIUM PERFRINGENS TYPES C AND D TOXINS IN HORSES A Thes1s by FRANCES LYNN BROOKS Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements... and content by: Russe B. Simpson~~ (Chairman of Committee) (21 ) /'' James E. Grimes (Nember) John M. Bowen (Nember) Ian R. Tizard (Head of Department) December 1983 ABSTRACT The Induction of Toxin Neutraliz1ng Ant1bodies to Clostridium Oeeff ti...

Brooks, Frances Lynn

2012-06-07

63

Purification, crystallization and preliminary X-ray diffraction studies of alpha-toxin of Clostridium perfringens.  

PubMed

Alpha-toxin of Clostridium perfringens, cloned in Escherichia coli, has been purified and crystallized from ammonium sulphate using the hanging drop vapour diffusion method at 20 degrees C. The crystals diffract to a minimum Bragg spacing of 2.7 A, belong to the space group R32 (with a = b = 153.3 A, c = 95.4 A, alpha = beta = 90 degrees and gamma = 120 degrees) and contain a single polypeptide chain in the crystallographic unit. PMID:7990145

Basak, A K; Stuart, D I; Nikura, T; Bishop, D H; Kelly, D C; Fearn, A; Titball, R W

1994-12-16

64

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

65

Intra-species growth-inhibition by Clostridium perfringens is a possible virulence trait in necrotic enteritis in broilers.  

PubMed

Necrotic enteritis in broiler chickens is associated with Clostridium perfringens type A, carrying the NetB toxin. C. perfringens type A is also a member of the normal intestinal microbiota of broilers. Clinically healthy chickens carry several different C. perfringens clones in their intestine. In flocks suffering from necrotic enteritis, however, mostly only one single clone is isolated from the gut of all the diseased animals. Selective proliferation of these clinical outbreak strains in the gut and spread within the flock seems likely, but an explanation has not yet been given. The hypothesis that necrotic enteritis associated C. perfringens strains might suppress the growth of normal microbiota C. perfringens strains, was therefore tested. Twenty-six C. perfringens strains isolated from healthy broilers and 24 clinical outbreak isolates were evaluated for their ability to induce intra-species growth-inhibition in an in vitro setup. A significantly higher proportion of the C. perfringens clinical outbreak strains inhibited the growth of other C. perfringens strains compared to C. perfringens strains isolated from the gut of healthy chickens. It is proposed that, in addition to toxin production, intra-species growth-inhibition may be a virulence trait that contributes to the ability of certain C. perfringens strains to cause necrotic enteritis in broilers. PMID:19201552

Timbermont, Leen; Lanckriet, Anouk; Pasmans, Frank; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip

2009-06-12

66

Inactivation of Cryptosporidium parvum oocysts and Clostridium perfringens spores by a mixed-oxidant disinfectant and by free chlorine.  

PubMed Central

Cryptosporidium parvum oocysts and Clostridium perfringens spores are very resistant to chlorine and other drinking-water disinfectants. Clostridium perfringens spores have been suggested as a surrogate indicator of disinfectant activity against Cryptosporidium parvum and other hardy pathogens in water. In this study, an alternative disinfectant system consisting of an electrochemically produced mixed-oxidant solution (MIOX; LATA Inc.) was evaluated for inactivation of both Cryptosporidium parvum oocysts and Clostridium perfringens spores. The disinfection efficacy of the mixed-oxidant solution was compared to that of free chlorine on the basis of equal weight per volume concentrations of total oxidants. Batch inactivation experiments were done on purified oocysts and spores in buffered, oxidant demand-free water at pH 7 an 25 degrees C by using a disinfectant dose of 5 mg/liter and contact times of up to 24 h. The mixed-oxidant solution was considerably more effective than free chlorine in activating both microorganisms. A 5-mg/liter dose of mixed oxidants produced a > 3-log10-unit (> 99.9%) inactivation of Cryptosporidium parvum oocysts and Clostridium perfringens spores in 4 h. Free chlorine produce no measurable inactivation of Cryptosporidium parvum oocysts by 4 or 24 h, although Clostridium perfringens spores were inactivated by 1.4 log10 units after 4 h. The on-site generation of mixed oxidants may be a practical and cost-effective system of drinking water disinfection protecting against even the most resistant pathogens, including Cryptosporidium oocysts. PMID:9097455

Venczel, L V; Arrowood, M; Hurd, M; Sobsey, M D

1997-01-01

67

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

68

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

69

Clostridium perfringens growth from spore inocula in sous-vide processed pork-based Mexican entrée.  

PubMed

The combined effect of Citricidal wih irradiation on Clostridium perfringens growth from spores in a sous-vide processed marinated pork meat Mexican entrée was investigated. Citricidal was added at 200 or 800 ppm after mixing pork meat with tomatillo sauce and inoculated with 3 log(10) CFU/g of C. perfringens spores. Samples were irradiated at either 0 or 2 kGy, heated to an internal temperature of 71 degrees C, and stored at 4 degrees C for 28 d, 15 degrees C for 45 d, and 25 degrees C for 26 h. To simulate the conditions that may occur during transportation, distribution, storage, or handling in supermarkets or by consumers, the effect of static temperature abuse on C. perfringens growth was assessed by transferring samples stored at 4 to 25 degrees C for 13 and 15 h. Total C. perfringens populations were determined by plating diluted samples on tryptose-sulfite-cycloserine agar. Growth was not observed up to 45 d of storage at 15 degrees C in samples supplemented with 800 ppm of Citricidal. At 25 degrees C, no significant differences (P > 0.05) on the lag phase duration due to antimicrobial treatments was observed. The temperature abuse of refrigerated products for up to 15 h did not lead to C. perfringens growth to high infective dose levels of 1 million cells required to cause food poisoning. The results suggest that 800 ppm Citricidal can have significant bacteriostatic activity against C. perfringens and may provide a degree of protection against this pathogen in sous-vide processed marinated pork meat Mexican entrée, under mild temperature abuse (

Miguel-Garcia, Denise Y; Juneja, Vijay K; Valenzuela-Melendrez, Martin; Díaz-Cinco, Martha E; Thippareddi, H; Aida Peña-Ramos, E

2009-01-01

70

TpeL-producing strains of Clostridium perfringens type A are highly virulent for broiler chicks.  

PubMed

Clostridium perfringens type A and type C are causative agents of necrotic enteritis (NE) in poultry. TpeL, a recently-described novel member of the family of large clostridial cytotoxins, was found in C. perfringens type C. Others have since reported TpeL in type A isolates from NE outbreaks, suggesting that it may contribute to the pathogenesis of NE. The virulence of TpeL-positive and -negative C. perfringens strains from cases of NE was examined by challenge of broiler chicks. Gross lesions typical of NE were observed in all challenged birds, and those inoculated with TpeL(pos) strains had higher average macroscopic lesion scores than those inoculated with a TpeL(neg) strain. Infection with TpeL(pos) strains may yield disease with a more rapid course and higher case fatality rate. Thus, TpeL may potentiate the effect of other virulence attributes of NE strains of C. perfringens. However, TpeL(pos) and Tpel(neg) strains compared here were not isogenic, and definitive results await the production and testing of specific TpeL mutants. PMID:22019986

Coursodon, C F; Glock, R D; Moore, K L; Cooper, K K; Songer, J G

2012-02-01

71

Growth of Clostridium perfringens from spore inocula in sous-vide turkey products.  

PubMed

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag ground turkey (pH 6) that included 0.3% (w/w) sodium pyrophosphate, and sodium chloride at 0, 1, 2, or 3% (w/w). The packages were processed to an internal temperature of 71.1 degrees 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 at 37 degrees C for 48 h. At 28 degrees C, the addition of 3% salt in turkey was effective in delaying growth for 12 h. At 15 degrees C, growth occurred at a relatively slow rate in the presence of 1-2% salt. Vegetative cells were not observed even after 28 days of storage in the presence of 3% salt. C. perfringens growth was not observed at 4 degrees C regardless of salt levels. The D-values ranged from 23.2 min (no salt) to 17.7 min (3% salt). Cyclic and static temperature abuse of refrigerated products for 8 h did not lead to growth by C. perfringens from a spore inoculum. PMID:8880332

Juneja, V K; Marmer, B S

1996-09-01

72

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

73

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, Josée; Masson, Luke; Archambault, Marie

2012-01-01

74

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

75

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

76

Purification of the alpha toxin of Clostridium perfringens type A by ultrafiltration and gel chromatography.  

PubMed

Clostridium perfringens type A toxin produced in Jayko & Lichstein medium was subjected to various concentration and purification procedures. The results obtained with 3 different ultrafiltration membranes followed by gel filtration showed that by using Millipore PSED OHV10 and Amicon XM-100 filter membranes in combination, a three-hundred-and-fivefold purification could be achieved as against a twelvefold increase obtained with ammonium sulphate/acetone precipitation. The lecitovitelin test was more sensitive than the haemolytic activity in determining the alpha toxin activity. The optical density, measured at 280 nm, did not reveal any alpha toxin activity in the relevant toxic fractions. PMID:2884611

Odendaal, M W

1987-03-01

77

Expression, crystallization and preliminary X-ray diffraction studies of recombinant Clostridium perfringens beta 2-toxin.  

PubMed

Clostridium perfringens is a Gram-positive sporulating anaerobic bacterium that is responsible for a wide spectrum of diseases in animals, birds and humans. The virulence of C. perfringens is associated with the production of several enterotoxins and exotoxins. beta2-toxin is a 28 kDa exotoxin produced by C. perfringens. It is implicated in necrotic enteritis in animals and humans, a disease characterized by a sudden acute onset with lethal hemorrhagic mucosal ulceration. The recombinant expression, purification and crystallization of beta2-toxin using the batch-under-oil technique are reported here. Native X-ray diffraction data were obtained to 2.9 A resolution on a synchrotron beamline at the F2 station at Cornell High Energy Synchrotron Source (CHESS) using an ADSC Quantum-210 CCD detector. The crystals belong to space group R3, with a dimer in the asymmetric unit; the unit-cell parameters are a = b = 103.71, c = 193.48 A, alpha = beta = 90, gamma = 120 degrees using the hexagonal axis setting. A self-rotation function shows that the two molecules are related by a noncrystallographic twofold axis with polar angles omega = 90.0, phi = 210.3 degrees. PMID:17554168

Gurjar, Abhijit A; Yennawar, Neela H; Yennawar, Hemant P; Rajashankar, Kanagalaghatta R; Hegde, Narasimha V; Jayarao, Bhushan M

2007-06-01

78

Antibiotic resistance of Clostridium perfringens isolates from broiler chickens in Egypt.  

PubMed

The use of antibiotic feed additives in broiler chickens results in a high prevalence of resistance among their enteric bacteria, with a consequent emergence of antibiotic resistance in zoonotic enteropathogens. Despite growing concerns about the emergence of antibiotic-resistant strains, which show varying prevalences in different geographic regions, little work has been done to investigate this issue in the Middle East. This study provides insight into one of the world's most common and financially crippling poultry diseases, necrotic enteritis caused by Clostridium perfringens. The study was designed to determine the prevalence of antibiotic resistance in C. perfringens isolates from clinical cases of necrotic enteritis in broiler chickens in Egypt. A total of 125 isolates were obtained from broiler flocks in 35 chicken coops on 17 farms and were tested using the disc diffusion method. All 125 isolates were resistant to gentamicin, streptomycin, oxolinic acid, lincomycin, erythromycin and spiramycin. The prevalence of resistance to other antibiotics was also high: rifampicin (34%), chloramphenicol (46%), spectinomycin (50%), tylosin-fosfomycin (52%), ciprofloxacin (58%), norfloxacin (67%), oxytetracycline (71%), flumequine (78%), enrofloxacin (82%), neomycin (93%), colistin (94%), pefloxacin (94%), doxycycline (98%) and trimethoprim-sulfamethoxazole (98%). It is recommended that C. perfringens infections in Egypt should be treated with antibiotics for which resistant isolates are rare at present; namely, amoxicillin, ampicillin, cephradine, fosfomycin and florfenicol. PMID:24761735

Osman, K M; Elhariri, M

2013-12-01

79

Draft Genome Sequence of Clostridium perfringens Strain JJC, a Highly Efficient Hydrogen Producer Isolated from Landfill Leachate Sludge.  

PubMed

Clostridium perfringens strain JJC is an effective biohydrogen and biochemical producer that was isolated from landfill leachate sludge. Here, we present the assembly and annotation of its genome, which may provide further insights into the gene interactions involved in efficient biohydrogen production. PMID:24604637

Wong, Y M; Juan, J C; Gan, H M; Austin, C M

2014-01-01

80

AN EVALUATION OF ASCORBIC ACID AS A QUORUM SENSING ANALOGUE TO CONTROL GROWTH, SPORULATION, AND ENTEROTOXIN PRODUCTION IN CLOSTRIDIUM PERFRINGENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inhibition of quorum sensing by enterotoxin-producing strains of Clostridium perfringens was investigated. Autoinducer-2 (AI-2) activity was measured in the presence and absence of ascorbic acid (vitamin C; concentrations ranging from 10 to 300 mM), an AI-2 analogue. Subsequent effects on AI-2 pro...

81

CONTROL OF CLOSTRIDIUM PERFRINGENS GERMINATION AND OUTGROWTH BY BUFFERED SODIUM CITRATE DURING CHILLING OF ROAST BEEF AND INJECTED PORK.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inhibition of Clostridium perfringens germination and outgrowth by buffered sodium citrate and buffered sodium citrate supplemented with sodium diacetate was evaluated during abusive chilling of roast beef and injected pork. Beef top rounds and pork loins were injected with a brine containing NaCl (...

82

CONTROL OF CLOSTRIDIUM PERFRINGENS GERMINATION AND OUTGROWTH BY BUFFERED SODIUM CITRATE DURING CHILLING OF ROAST BEEF AND INJECTED PORK  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inhibition of Clostridium perfringens germination and outgrowth by buffered sodium citrate and buffered sodium citrate supplemented with sodium diacetate was evaluated during abusive chilling of roast beef and injected pork. Beef top rounds and pork loins were injected with a brine containing NaCl (...

83

Role of alpha-toxin in Clostridium perfringens infection determined by using recombinants of C. perfringens and Bacillus subtilis.  

PubMed Central

Clostridium perfringens type A strains which differed in alpha-toxin (phospholipase C [PLC]) productivity were inoculated intraperitoneally or intravenously into mice, and then their 50% mouse lethal doses (LD50) were determined. Strain NCTC 8237 produced ninefold higher PLC activity than strain 13. The mean LD50 for the former was 1 log unit lower than that for the latter. Two isogenic strains were constructed from strain 13: strain 13(pJIR418 alpha) (pJIR418 alpha contains the plc gene), which produced ninefold higher PLC activity than strain 13; and strain 13 PLC-, which showed no PLC productivity at all because of transformation-mediated gene disruption. The mean LD50 for strain 13(pJIR418 alpha) was 1 log unit lower than those for strain 13 PLC- and strain 13. These results indicate that PLC functions as a virulence-determining factor when it is produced in a sufficient amount. Such a difference in LD50 was also observed between Bacillus subtilis with and without the cloned plc gene. Inoculation of B. subtilis PLC+ intravenously into mice caused marked thrombocytopenia and leukocytosis. Mice inoculated with B. subtilis at 2 LD50 died because of circulatory collapse. Histological examination revealed that intravascular coagulation and vascular congestion occurred most prominently in the lungs. These results suggest that PLC plays a key role in the systemic intoxication of clostridial myonecrosis, probably by affecting the functions of platelets and phagocytes. Images PMID:7927785

Ninomiya, M; Matsushita, O; Minami, J; Sakamoto, H; Nakano, M; Okabe, A

1994-01-01

84

Detection of Clostridium perfringens in yearling lamb meat (barbacoa), head, and gut tacos from public markets in Mexico City.  

PubMed

No reports on the incidence of Clostridium perfringens in popularly-consumed food from Mexico City have been published; neither are there any reports that have analyzed food consumed in popular markets and less established restaurants. Therefore, this study is aimed at providing data to evaluate the relevance of C. perfringens as an etiologic agent of food-borne diseases. Of the 650 analyzed samples, 106 (16.3%) were positive for C. perfringens; 6.4% (16/250) isolates were from barbacoa, 19% (38/200) from head, and 13% (52/200) from gut tacos. The presence of C. perfringens in these popular-consumed foods demonstrates its relevance as an etiologic agent of food-borne diseases, and confirms the great sanitary risk involved in their consumption. These results may serve as a basis for the Mexican sanitary authorities to control the microbiological quality of street-made foods. PMID:20198526

Natividad-Bonifacio, Iván; Vázquez-Quiñones, Carlos R; Rodas-Suárez, Oscar R; Fernández, Francisco J; Rodríguez-Solis, Esteban; Quiñones-Ramírez, Elsa Irma; Vázquez-Salinas, Carlos

2010-06-01

85

Synergistic Effects of Clostridium perfringens Enterotoxin and Beta Toxin in Rabbit Small Intestinal Loops  

PubMed Central

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.

2014-01-01

86

Association between avian necrotic enteritis and Clostridium perfringens strains expressing NetB toxin  

PubMed Central

A novel toxin, NetB, has recently been identified in virulent avian Clostridium perfringens isolates and shown to be an essential virulence factor in a clinical necrotic enteritis isolate. To assess whether NetB is more generally associated with avian necrotic enteritis isolates we have screened a range of C. perfringens strains from geographically diverse locations for both the presence and expression of the netB gene. Forty-four isolates were derived from necrotic enteritis disease cases from Australia, Belgium, Denmark and Canada and 55 isolates from healthy chickens from Australia and Belgium. The majority of strains isolated from necrotic enteritis-affected birds were netB positive (70%) and there was an absolute correlation between the presence of netB and in vitro expression of the NetB protein. Only two of the C. perfringens isolates from healthy chickens carried netB. Sequencing of the netB gene from 23 positive isolates showed that NetB is highly conserved, with only one predicted amino acid (A168T) difference, in six isolates, compared to the published sequence. This change did not alter the in vitro activity of the NetB toxin. The gene encoding the recently discovered TpeL toxin was also screened using PCR and only found in a small proportion of NetB-positive isolates from diseased birds. A selection of NetB-negative isolates, originating from diseased birds, was unable to cause disease in a necrotic enteritis induction model. This study provides further evidence that NetB is important in pathogenesis and advances our current understanding of C. perfringens virulence factors in avian necrotic enteritis. PMID:19931005

Keyburn, Anthony L.; Yan, Xu-Xia; Bannam, Trudi L.; Van Immerseel, Filip; Rood, Julian I.; Moore, Robert J.

2009-01-01

87

Validation of bacon processing conditions to verify control of Clostridium perfringens and Staphylococcus aureus.  

PubMed

It is unclear how rapidly meat products, such as bacon, that have been heat treated but not fully cooked should be cooled to prevent the outgrowth of spore-forming bacterial pathogens and limit the growth of vegetative cells. Clostridium perfringens spores and vegetative cells and Staphylococcus aureus cells were inoculated into ground cured pork bellies with and without 1.25% liquid smoke. Bellies were subjected to the thermal profiles of industrial smoking to 48.9 degrees C (120 degrees F) and normal cooling of bacon (3 h) as well as a cooling phase of 15 h until the meat reached 7.2 degrees C (45 degrees F). A laboratory-scale bacon smoking and cooling operation was also performed. Under normal smoking and cooling thermal conditions, growth of C. perfringens in ground pork bellies was <1 log regardless of smoke. Increase of S. aureus was 2.38 log CFU/g but only 0.68 log CFU/g with smoke. When cooling spanned 15 h, both C. perfringens and S. aureus grew by a total of about 4 log. The addition of liquid smoke inhibited C. perfringens, but S. aureus still achieved a 3.97-log increase. Staphylococcal enterotoxins were detected in five of six samples cooled for 15 h without smoke but in none of the six samples of smoked bellies. In laboratory-scale smoking of whole belly pieces, initial C. perfringens populations of 2.23 +/- 0.25 log CFU/g were reduced during smoking to 0.99 +/- 0.50 log CFU/g and were 0.65 +/- 0.21 log CFU/g after 15 h of cooling. Populations of S. aureus were reduced from 2.00 +/- 0.74 to a final concentration of 0.74 +/- 0.53 log CFU/g after cooling. Contrary to findings in the ground pork belly system, the 15-h cooling of whole belly pieces did not permit growth of either pathogen. This study demonstrates that if smoked bacon is cooled from 48.9 to 7.2 degrees C (120 to 45 degrees F) within 15 h, a food safety hazard from either C. perfringens or S. aureus is not likely to occur. PMID:16161681

Taormina, Peter J; Bartholomew, Gene W

2005-09-01

88

Growth potential of Clostridium perfringens from spores in acidified beef, pork, and poultry products during chilling.  

PubMed

The ability of Clostridium perfringens to germinate and grow in acidified ground beef as well as in 10 commercially prepared acidified beef, pork, and poultry products was assessed. The pH of ground beef was adjusted with organic vinegar to achieve various pH values between 5.0 and 5.6; the pH of the commercial products ranged from 4.74 to 6.35. Products were inoculated with a three-strain cocktail of C. perfringens spores to achieve ca. 2-log (low) or 4-log (high) inoculum levels, vacuum packaged, and cooled exponentially from 54.4 to 7.2°C for 6, 9, 12, 15, 18, or 21 h to simulate abusive cooling; the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) recommends a cooling time of 6.5 h. Total germinated C. perfringens populations were determined after plating on tryptose-sulfite-cycloserine agar and incubating the plates anaerobically at 37°C for 48 h. In addition, C. perfringens growth from spores was assessed at an isothermal temperature of 44°C. Growth from spores was inhibited in ground beef with a pH of 5.5 or below, even during extended cooling from 54.4 to 7.2°C in 21 h. In ground beef with a pH of 5.6, the growth was >1 log after 18 h of cooling from 54.4 to 7.2°C. However, 15 h of cooling controlled the growth to <1 log, regardless of the inoculum level. In addition, no growth was observed in any product with a pH ranging from 4.74 to 5.17, both during exponential abusive cooling periods of up to 21 h and during storage for 21 h at 44°C. While <1-log growth of C. perfringens from spores was observed in the pH 5.63 product cooled exponentially from 54.4 to 7.2°C in 15 h or less, the pH 6.35 product supported growth, even after 6 h of cooling from 54.4 to 7.2°C. These challenge tests demonstrate that adjustment of ground beef to pH of 5.5 or less and of barbeque products to pH of 5.63 or less inhibits C. perfringens spore germination and outgrowth during extended cooling periods from 54.4 to 7.2°C up to 15 h. Therefore, safe cooling periods for products with homogeneous, lower pHs can be substantially longer. PMID:23317858

Juneja, Vijay K; Baker, David A; Thippareddi, H; Snyder, O Peter; Mohr, Tim B

2013-01-01

89

Comparative Experiments To Examine the Effects of Heating on Vegetative Cells and Spores of Clostridium perfringens Isolates Carrying Plasmid Enterotoxin Genes versus Chromosomal Enterotoxin Genes  

Microsoft Academic Search

Clostridium perfringens enterotoxin (CPE) is an important virulence factor for both C. perfringens type A food poisoning and several non-food-borne human gastrointestinal diseases. Recent studies have indicated that C. perfringens isolates associated with food poisoning carry a chromosomal cpe gene, while non-food-borne human gastrointestinal disease isolates carry a plasmid cpe gene. However, no explanation has been provided for the strong

MAHFUZUR R. SARKER; ROBERT P. SHIVERS; SHAUNA G. SPARKS; VIJAY K. JUNEJA; B. A. McClane

2000-01-01

90

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

91

Production of a bacteriocin by a poultry derived Campylobacter jejuni isolate with antimicrobial activity against Clostridium perfringens and other Gram positive bacteria.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have purified a bacteriocin peptide (termed CUV-3), produced by a poultry cecal isolate of Campylobacter jejuni (strain CUV-3) with inhibitory activity against Gram positive bacteria including Clostridium perfringens (38 strains), Staphylococcus aureus, Staphylococcus epidermidis and Listeria mon...

92

The Clostridium perfringens enterotoxin from equine isolates; its characterization, sequence and role in foal diarrhoea.  

PubMed Central

During a survey of foal diarrhoea between 1991 and 1994, Clostridium perfringens was significantly associated with disease with 56% of cases infected [1]. The contribution of enterotoxigenic C. perfringens to this association, was assessed by use of the reverse passive latex agglutination test for enterotoxin (RPLA; Oxoid Unipath) and vero cell toxicity neutralized by antitoxin on stored faecal samples and sporulated faecal isolates of C. perfringens. Polymerase chain reaction (PCR1) based on the DNA sequence for the whole enterotoxin gene [2] yielded a fragment from an equine isolate of the anticipated size which, cloned into plasmid M13 phage, had a sequence essentially identical to the published sequence. Consequently, all faecal isolates were also tested by PCR1 and for a part of the enterotoxin gene (PCR2). Significant association with diarrhoea (controls not in contact with cases) was found with positive RPLA tests on faeces (OR = 13, P = 0.002) and isolates (OR = 4.57, P = < 0.0001), vero cell toxicity of isolates (OR = 1.78, P = 0.026), and PCR1 (OR = nd, P = 0.029) but not PCR2 or vero cell toxicity of faeces. Significant association with diarrhoea was also found for isolates negative by RPLA (OR = 3.91; CI 2.05-7.57; P < 0.0001) or PCR1 (OR = 4.81; CI 2.84-8.20; P < 0.0001). Many of the isolates from RPLA positive faeces and verotoxic isolates were PCR negative and no evidence could be found for the presence of the enterotoxin gene in a random selection of RPLA positive/PCR negative isolates by gene probe on chromosomal DNA and PCR reaction product or vero cell toxicity neutralized by specific antiserum. Failure of the vero cell toxicity on faeces to be associated with diarrhoea or for cytotoxicity of cultures and RPLA on cultures to agree with the PCRs was believed to be related to the presence of other cytotoxins, the inherent cytotoxicity of equine faeces and to the poor specificity of the commercial antiserum used in the test. Enterotoxigenic C. perfringens could not account for the overall association of C. perfringens with foal diarrhoea because (a) cultures positive by PCR, RPLA or cytotoxicity were not significantly more common amongst isolates from cases than controls; and (b) the proportion of isolates from cases positive by PCR (PCR1 or PCR2) was too small at 9.7%. PMID:9593490

Netherwood, T.; Binns, M.; Townsend, H.; Wood, J. L.; Mumford, J. A.; Chanter, N.

1998-01-01

93

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

94

Enzootic outbreak of necrotic gastritis associated with Clostridium perfringens in broiler chickens.  

PubMed

Clinical morphological investigations were carried out in a flock of 22,000 Ross 308 broiler chickens at the age of 38 days that experienced a sudden increase in mortality rates. Morbidity and mortality rates were followed and gross anatomical examination of 150 bodies (7%) of all 1541 dead chickens was performed. In all necropsied birds, without exception, the typical macroscopic lesions were observed only in the gizzard. Focal or diffuse pseudomembranous deposits were found subcuticularly and on the gizzard mucous coat. Microscopically, hyalinization, desquamated epithelial cells and single foci of microorganisms were present among the formed pseudomembranes. Among the fibrin networks of coagulated exudate, a single bacilli were detected. Clostridium perfringens was isolated from all gastric samples investigated. Polymerase chain reactions were positive for alpha-toxin and negative for beta-toxin and beta(2)-toxin. PMID:20390530

Dinev, Ivan

2010-02-01

95

Origin of Clostridium perfringens isolates determines the ability to induce necrotic enteritis in broilers.  

PubMed

Since the ban on growth-promoting antibiotics in animal feed in the European Union, necrotic enteritis has become a major cause of mortality in broiler chickens. Despite the importance of the disease, the pathogenesis is still not completely understood. In the current study, Clostridium perfringens strains isolated from healthy flocks and isolates from outbreaks of necrotic enteritis were evaluated for the ability to cause gut necrosis in an intestinal loop model in laying hens and in an experimental infection model in broilers. High, intermediate and low alpha toxin producing strains were chosen from each isolation source. Only the isolates from field outbreaks induced necrotic gut lesions, independent of the amount of alpha toxin produced in vitro. It was also shown that alpha toxin producing isolates from calf hemorrhagic enteritis cases were not able to induce necrotic enteritis in poultry. These results suggest the presence of host specific virulence factors in C. perfringens strains, isolated from chickens with intestinal necrotic enteritis lesions. PMID:18783830

Timbermont, Leen; Lanckriet, Anouk; Gholamiandehkordi, Ahmad R; Pasmans, Frank; Martel, An; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip

2009-11-01

96

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

97

Inhibition of Clostridium perfringens growth by potassium lactate during an extended cooling of cooked uncured ground turkey breasts.  

PubMed

The U.S. Department of Agriculture's Food Safety and Inspection Service compliance guideline known as Appendix B specifies chilling time and temperature limits for cured and uncured meat products to inhibit growth of spore-forming bacteria, particularly Clostridium perfringens. Sodium lactate and potassium lactate inhibit toxigenic growth of Clostridium botulinum, and inhibition of C. perfringens has been reported. In this study, a cocktail of spores of three C. perfringens strains (ATCC 13124, ATCC 12915, and ATCC 12916) were inoculated into 100-g samples of ground skinless, boneless turkey breast formulated to represent deli-style turkey breast. Three treatment groups were supplemented with 0 (control), 1, or 2% potassium lactate (pure basis), cooked to 71 °C, and assayed for C. perfringens growth during 10 or 12 h of linear cooling to 4 °C. In control samples, populations of C. perfringens increased 3.8 to 4.7 log CFU/g during the two chilling protocols. The 1% potassium lactate treatment supported only a 2.5- to 2.7-log increase, and the 2% potassium lactate treatment limited growth to a 0.56- to 0.70-log increase. When compared with the control, 2% potassium lactate retarded growth by 2.65 and 4.21 log CFU/g for the 10- and 12-h cooling protocols, respectively. These results confirm that the addition of 2% potassium lactate inhibits growth of C. perfringens and that potassium lactate can be used as an alternative to sodium nitrite for safe extended cooling of uncured meats. PMID:24215704

Kennedy, Katherine M; Milkowski, Andrew L; Glass, Kathleen A

2013-11-01

98

Lyophilized Clostridium perfringens 3 alpha- and Clostridium bifermentans 7 alpha-hydroxysteroid dehydrogenases: two new stable enzyme preparations for routine bile acid analysis.  

PubMed

Preparations of 3 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.50) from Clostridium perfringens were successfully lyophilized into a stable powder form. Purification of the enzyme was achieved using triazine dye affinity chromatography. C. perfringens 3 alpha-hydroxysteroid dehydrogenase was purified 24-fold using Reactive Red 120 (Procion Red) -cross-linked agarose (70% yield). Quantitative measurement of bile acids with the purified enzymes, 3 alpha-hydroxysteroid dehydrogenase and 7 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.159) from Clostridium bifermentans (strain F-6), was achieved spectrophotometrically. Standard curves with chenodeoxycholic acid (CDC) and cholic acid were linear within a concentration range of 20-100 microM. Analysis of mixtures of ursodeoxycholic acid and CDC showed the additive nature of the 3 alpha-hydroxysteroid dehydrogenase and showed also that 7 alpha-hydroxyl groups were independently quantified by the 7 alpha-hydroxysteroid dehydrogenase. Bile acids in Folch extracts of human bile samples were measured using purified preparations of Pseudomonas testosteroni 3 alpha-hydroxysteroid dehydrogenase, C. perfringens 3 alpha-hydroxysteroid dehydrogenase, Escherichia coli 7 alpha-hydroxysteroid dehydrogenase and C. bifermentans (strain F-6) 7 alpha-hydroxysteroid dehydrogenase. Statistical comparison validated the use of C. perfringens 3 alpha- and C. bifermentans 7 alpha-hydroxysteroid dehydrogenases for the quantification of bile acids in bile. PMID:2901274

Sutherland, J D; Hutchison, D M; Williams, C N

1988-09-01

99

Comparative Neuropathology of Ovine Enterotoxemia Produced by Clostridium perfringens Type D Wild-Type Strain CN1020 and Its Genetically Modified Derivatives.  

PubMed

Clostridium perfringens type D causes enterotoxemia in sheep and goats. The disease is mediated by epsilon toxin (ETX), which affects the cerebrovascular endothelium, increasing vascular permeability and leading to cerebral edema. In the present study, we compared the distribution and severity of the cerebrovascular changes induced in lambs by C. perfringens type D strain CN1020, its isogenic etx null mutant, and the ETX-producing complemented mutant. We also applied histochemical and immunohistochemical markers to further characterize the brain lesions induced by ETX. Both ETX-producing strains induced extensive cerebrovascular damage that did not differ significantly between each other in nature, neuroanatomic distribution, or severity. By contrast, lambs inoculated with the etx mutant or sterile, nontoxic culture medium did not develop detectable brain lesions, confirming that the neuropathologic effects observed in these infections are dependent on ETX production. Lambs treated with the wild-type and complemented strains showed perivascular and mural vascular edema, as well as serum albumin extravasation, particularly severe in the cerebral white matter, midbrain, medulla oblongata, and cerebellum. Brains of animals inoculated with the ETX-producing strains showed decreased expression of glial fibrillary acidic protein and increased expression of aquaporin-4 in the end-feet processes of the astrocytes around blood vessels. Early axonal injury was demonstrated with anti-amyloid precursor protein immunohistochemistry. Perivascular accumulation of macrophages/microglia with intracytoplasmic albumin globules was also observed in these animals. This study demonstrates that ETX is responsible for the major cerebrovascular changes in C. perfringens type D-induced disease. PMID:24964921

Garcia, J P; Giannitti, F; Finnie, J W; Manavis, J; Beingesser, J; Adams, V; Rood, J I; Uzal, F A

2014-06-25

100

Effects of Clostridium perfringens enterotoxin via claudin-4 on normal human pancreatic duct epithelial cells and cancer cells  

Microsoft Academic Search

The tight junction protein claudin-4 is frequently overexpressed in pancreatic cancer, and is also a receptor for Clostridium perfringens enterotoxin (CPE). The cytotoxic effects of CPE are thought to be useful as a novel therapeutic tool for pancreatic cancer.\\u000a However, the responses to CPE via claudin-4 remain unknown in normal human pancreatic duct epithelial (HPDE) cells. We introduced\\u000a the human

Hiroshi Yamaguchi; Takashi Kojima; Tatsuya Ito; Daisuke Kyuno; Yasutoshi Kimura; Masafumi Imamura; Koichi Hirata; Norimasa Sawada

101

Sequence of the amino-terminal part of enterotoxin from Clostridium perfringens type A: identification of points of trypsin activation.  

PubMed Central

The sequence of the first 66 amino acids of the amino-terminal part of the enterotoxin from Clostridium perfringens type A is presented. The trypsin activation of the enterotoxin involves hydrolysis of Lys15-Glu16 and Lys25-Thr26 bonds. The N-terminal sequence of the trypsin-activated enterotoxin has limited homology with the sequence of the N-terminal region of the cholera toxin B subunit. PMID:6303961

Richardson, M; Granum, P E

1983-01-01

102

Genome mapping of Clostridium perfringens strains with I- Ceu I shows many virulence genes to be plasmid-borne  

Microsoft Academic Search

The intron-encoded endonuclease I-CeuI fromChlamydomonas eugametos was shown to cleave the circular chromosomes of allClostridium perfringens strains examined at single sites in the rRNA operons, thereby generating ten fragments suitable for the rapid mapping of virulence genes by pulsed-field gel electrophoresis (PFGE). This method easily distinguishes between plasmid and chromosomal localisations, as I-CeuI only cuts chromosomal DNA. Using this approach,

S. Katayama; B. Dupuy; S. T. Cole; G. Daube; B. China

1996-01-01

103

Identification and Characterization of Sporulation-Dependent Promoters Upstream of the Enterotoxin Gene (cpe )o f Clostridium perfringens  

Microsoft Academic Search

Three promoter sites (P1, P2, and P3) responsible for the sporulation-associated synthesis of Clostridium perfringens enterotoxin, a common cause of food poisoning in humans and animals, were identified. Nested and internal deletions of the cpe promoter region were made to narrow down the location of promoter elements. To measure the effects of the deletions on the expression of cpe, translational

YULING ZHAO; STEPHEN B. MELVILLE

1998-01-01

104

Alpha-Toxin of Clostridium perfringens Is Not an Essential Virulence Factor in Necrotic Enteritis in Chickens?  

PubMed Central

The Clostridium perfringens alpha-toxin has previously been implicated as the major virulence factor in necrotic enteritis in chickens, although definitive proof has not been reported. In this study an alpha-toxin mutant was constructed in a virulent chicken isolate and shown to retain full virulence in a chicken disease model. These results demonstrated that alpha-toxin is not an essential virulence factor in the pathogenesis of necrotic enteritis in chickens. PMID:16923791

Keyburn, Anthony?L.?; Sheedy, Scott A.; Ford, Mark E.; Williamson, Mark M.; Awad, Milena M.; Rood, Julian I.; Moore, Robert J.

2006-01-01

105

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

PubMed

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 long-term exposure trials, the birds were orally inoculated daily, with 1 ml (1.0 or 2 x 10(8) CFU/ml) of an overnight culture of C. perfringens for 7 days. Short-term exposure trials involved challenge with 1 ml (3 x 10(10) CFU/ml) administered as a single dose. The responses of broilers to orally administered C. perfingens under laboratory controlled conditions are presented and discussed in the context of authentic field cases of necrotic enteritis. None of the challenge trials produced overt clinical signs of NE and there were no mortalities associated with oral exposure to high doses of C. perfringens. However, many of the challenged birds showed distinctly pronounced pathological changes in the intestinal tissue. On gross examination the responses in birds challenged orally with C. perfringens could be placed into two categories: (1) no apparent pathological changes in the intestinal tissue and (2) sub-clinical inflammatory responses with focal, multi-focal, locally extensive, or disseminated distribution throughout various sections of duodenum, jejunum, ileum, and ceca. In birds that responded with intestinal lesions, hyperemia and occasional hemorrhages were the main gross changes. In some birds, the mucosa was covered with a brownish material, but typically, the mucosa was lined by yellow or greenish, loosely adherent material. Mild gross changes were seen in some control birds, but both qualitatively and quantitatively, the lesions were distinctly more pronounced in the challenged birds. Upon histological examination, none of the experimentally exposed birds showed overt mucosal necrosis typical of field cases of NE, but typically the lamina propria was hyperemic and infiltrated with numerous inflammatory cells. Most significant changes were seen at the interface of the basal domain of enterocytes and lamina propria. Multifocally, these areas were extensively edematous, allowing for the substantial disturbance of the structural integrity between the lamina propria and the enterocytes. The lesions observed in the present study were consistently reproduced in all of our challenge trials, hence these responses may signify newly emerging patterns of sub-clinical enteric disorders in contemporary strains of poultry. The pathological changes observed in broilers challenged orally with C. perfringens in the present study, differ significantly from those reported previously, and must be clearly differentiated from those described in cases of NE or ulcerative enteritis. Although no overt necrosis of the intestinal mucosa typical of field cases of NE were observed in the present study, the birds challenged with C. perfringens showed strong inflammatory reaction to the introduced pathogens. The distinct features of the microscopic lesions were changes involving apparently normal enterocytes at the interface of the basal domain of villar epithelia and lamina propria. Although the pathological changes in the intestinal tissues observed in our trials appear to be rather subtle when compared to field cases of NE, the nature of these lesions suggest a significant negative effect on the digestive physiology of intestinal mucosa. PMID:16337982

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

2006-08-01

106

How do swine practitioners and veterinary pathologists arrive at a diagnosis of Clostridium perfringens type A enteritis in neonatal piglets?  

PubMed Central

A questionnaire was administered to 22 veterinary practitioners and 17 veterinary pathologists to investigate the methods used for diagnosis of Clostridium perfringens type A enteritis in neonatal pigs. Practitioners generally diagnosed C. perfringens type A associated enteritis by age of onset of diarrhea (between 1 to 7 days of age). Most practitioners (95%) were moderately to very confident in their diagnosis. Pathologists generally diagnosed C. perfringens type A associated enteritis by combinations of isolation of the organism, genotyping or detecting the toxins of the organism, and ruling out other pathogens through histopathology. Almost half (41%) of the pathologists were not confident of their diagnosis. This study reports that the current diagnostic method for C. perfringens type A enteritis is not specific, and although many pathologists expressed reservations about making a diagnosis of C. perfringens type A enteritis, most practitioners were confident in their diagnosis, even though reported clinical signs of clostridial diarrhea are similar to those of a number of other enteric diseases. PMID:24155437

Chan, Gloria; Farzan, Abdolvahab; Prescott, John F.; Friendship, Robert

2013-01-01

107

Perfrin, a novel bacteriocin associated with netB positive Clostridium perfringens strains from broilers with necrotic enteritis.  

PubMed

Necrotic enteritis in broiler chickens is associated with netB positive Clostridium perfringens type A strains. It is known that C. perfringens strains isolated from outbreaks of necrotic enteritis are more capable of secreting factors inhibiting growth of other C. perfringens strains than strains isolated from the gut of healthy chickens. This characteristic could lead to extensive and selective presence of a strain that contains the genetic make-up enabling to secrete toxins that cause gut lesions. This report describes the discovery, purification, characterization and recombinant expression of a novel bacteriocin, referred to as perfrin, produced by a necrotic enteritis-associated netB-positive C. perfringens strain. Perfrin is a 11.5 kDa C-terminal fragment of a 22.9 kDa protein and showed no sequence homology to any currently known bacteriocin. The 11.5 kDa fragment can be cloned into Escherichia coli, and expression yielded an active peptide. PCR detection of the gene showed its presence in 10 netB-positive C. perfringens strains of broiler origin, and not in other C. perfringens strains tested (isolated from broilers, cattle, sheep, pigs, and humans). Perfrin and NetB are not located on the same genetic element since NetB is plasmid-encoded and perfrin is not. The bacteriocin has bactericidal activity over a wide pH-range but is thermolabile and sensitive to proteolytic digestion (trypsin, proteinase K). C. perfringens bacteriocins, such as perfrin, can be considered as an additional factor involved in the pathogenesis of necrotic enteritis in broilers. PMID:24708344

Timbermont, Leen; De Smet, Lina; Van Nieuwerburgh, Filip; Parreira, Valeria R; Van Driessche, Gonzalez; Haesebrouck, Freddy; Ducatelle, Richard; Prescott, John; Deforce, Dieter; Devreese, Bart; Van Immerseel, Filip

2014-01-01

108

Delayed Clostridium perfringens growth from a spore inocula by sodium lactate in sous-vide chicken products.  

PubMed

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag marinated chicken breast that included 0%, 1.5%, 3%, or 4.8% sodium lactate (NaL; w/w). The packages were processed to an internal temperature of 71.1 degrees C, ice chilled and stored at 4, 19, and 25 degrees C. 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 degrees C. At 25 degrees C, addition of 1.5% NaL was effective in delaying growth for 29 h. Increasing the NaL level to 4.8%, C. perfringens growth from a spore inoculum during storage at 25 degrees C for 480 h was not observed. At 19 degrees C, the growth was > 6 log 10 cfu/g by 288 h in control samples. In samples with 3.0% or 4.8% NaL, the growth of C. perfringens from spores was dramatically restricted with little or no growth in 648 h at 19 degrees C. C. perfringens growth was not observed at 4 degrees C regardless of NaL concentration. The D-values at 55 degrees C ranged from 47.40 (no NaL) to 57.58 min (1.5% NaL). Cyclic and static temperature abuse of refrigerated products for 20 h did not permit C. perfringens growth. However, temperature abuse of products for periods 24 h or longer in the absence of NaL led to growth of C. perfringens from a spore inoculum. An extra degree of safety may be assured in such products by supplementation with NaL at 1.5-4.8% NaL level. PMID:16942993

Juneja, Vijay K

2006-04-01

109

Rapid, Simultaneous Detection of Clostridium sordellii and Clostridium perfringens in Archived Tissues by a Novel PCR-Based Microsphere Assay: Diagnostic Implications for Pregnancy-Associated Toxic Shock Syndrome Cases  

PubMed Central

Clostridium sordellii and Clostridium perfringens are infrequent human pathogens; however, the case-fatality rates for the infections are very high, particularly in obstetric C. sordellii infections (>90%). Deaths from Clostridium sordellii and Clostridium perfringens toxic shock (CTS) are sudden, and diagnosis is often challenging. Formalin-fixed, paraffin-embedded (FFPE) tissues usually are the only specimens available for sudden fatal cases, and immunohistochemistry (IHC) for Clostridia is generally performed but it cannot identify species. A clear need exists for a rapid, species-specific diagnostic assay for FFPE tissues. We developed a duplex PCR-based microsphere assay for simultaneous detection of C. sordellii and C. perfringens and evaluated DNA extracted from 42 Clostridium isolates and FFPE tissues of 28 patients with toxic shock/endometritis (20?CTS, 8?non-CTS, as confirmed by PCR and sequencing). The microsphere assay correctly identified C. sordellii and C. perfringens in all known isolates and in all CTS patients (10 C. sordellii, 8 C. perfringens, 2 both) and showed 100% concordance with PCR and sequencing results. The microsphere assay is a rapid, specific, and cost-effective method for the diagnosis of CTS and offers the advantage of simultaneous testing for C. sordellii and C. perfringens in FFPE tissues using a limited amount of DNA. PMID:22536012

Bhatnagar, Julu; DeLeon-Carnes, Marlene; Kellar, Kathryn L.; Bandyopadhyay, Kakali; Antoniadou, Zoi-Anna; Shieh, Wun-Ju; Paddock, Christopher D.; Zaki, Sherif R.

2012-01-01

110

Clostridium perfringens iota toxin: characterization of the cell-associated iota b complex.  

PubMed Central

Clostridium perfringens type E iota toxin consists of two unlinked proteins designated as iota a (Ia; molecular mass approximately 47 kDa), an ADP-ribosyltransferase and iota b (Ib; molecular mass approximately 81 kDa) which binds to the cell surface and facilitates Ia entry into the cytosol. By Western-blot analysis, Ib incubated with Vero cells at 37 degrees C generated a cell-associated, SDS-insoluble oligomer of Ib (molecular mass>220 kDa) within 15 s, which was still evident 110 min after washing cells. Ib oligomerization was temperature, but not pH, dependent and was facilitated by a cell-surface protein(s). Within 5 min at 37 degrees C, cell-bound Ib generated Na(+)/K(+) permeable channels that were blocked by Ia. However, Ib-induced channels or oligomers were not formed at 4 degrees C. Two monoclonal antibodies raised against Ib that recognize unique, neutralizing epitopes within residues 632-655 either inhibited Ib binding to cells and/or oligomerization, unlike a non-neutralizing monoclonal antibody that binds within Ib residues 28-66. The Ib protoxin (molecular mass approximately 98 kDa), which does not facilitate iota cytotoxicity but binds to Vero cells, did not oligomerize or form ion-permeable channels on cells, and neither trypsin nor chymotrypsin treatment of cell-bound Ib protoxin induced large complex formation. The link between Ib oligomers and iota toxicity was also apparent with a resistant cell line (MRC-5), which bound to Ib with no evidence of oligomerization. Overall, these studies revealed that the biological activity of iota toxin is dependent on a long-lived, cell-associated Ib complex that rapidly forms ion-permeable channels in cell membranes. These results further reveal the similarities of C. perfringens iota toxin with other bacterial binary toxins produced by Bacillus anthracis and C. botulinum. PMID:12175336

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

2002-01-01

111

A large Clostridium perfringens foodborne outbreak with an unusual attack rate pattern.  

PubMed

On November 7, 1985, a Clostridium perfringens gastroenteritis outbreak occurred in approximately 44% of the 1,362 employees at a Connecticut factory. Although the same foods were served to all three shifts at an employee banquet on November 6, the attack rate was almost twice as high for those who ate on the day shift (attack rate = 50%) than for those on the evening shift (attack rate = 20%) or night shift (attack rate = 29%). Among employees of the day shift, attack rates were highest for those who ate during the first 30 minutes of the 2.5-hour day shift serving period and decreased throughout the serving period. The one-hour evening shift serving period had a similar trend toward higher attack rates earlier in the serving period. Four main-course foods were significantly associated with illness, and over 95% of the employees had eaten each of them. Stratified analysis indicated that gravy was the responsible food and, furthermore, that the decreasing attack rate pattern within serving periods occurred only for those who ate gravy. The gravy had been prepared 12-24 hours in advance of banquet service. After it was prepared, the gravy was improperly cooled and was reheated shortly before and throughout the serving periods. Persons who ate gravy that had been reheated for the longest period of time had the lowest attack rate, probably because they were exposed to a lower concentration of organisms. This outbreak underscores the need for properly reheating food to prevent C. perfringens gastroenteritis and suggests that analysis of attack rate trends may provide important epidemiologic clues to understanding the causes of foodborne disease outbreaks. PMID:2893540

Petersen, L R; Mshar, R; Cooper, G H; Bruce, A R; Hadler, J L

1988-03-01

112

Comparative transcription analysis and toxin production of two fluoroquinolone-resistant mutants of Clostridium perfringens  

PubMed Central

Background Fluoroquinolone use has been listed as a risk factor for the emergence of virulent clinical strains of some bacteria. The aim of our study was to evaluate the effect of fluoroquinolone (gatifloxacin) resistance selection on differential gene expression, including the toxin genes involved in virulence, in two fluoroquinolone-resistant strains of Clostridium perfringens by comparison with their wild-type isogenic strains. Results DNA microarray analyses were used to compare the gene transcription of two wild types, NCTR and ATCC 13124, with their gatifloxacin-resistant mutants, NCTRR and 13124R. Transcription of a variety of genes involved in bacterial metabolism was either higher or lower in the mutants than in the wild types. Some genes, including genes for toxins and regulatory genes, were upregulated in NCTRR and downregulated in 13124R. Transcription analysis by quantitative real-time PCR (qRT-PCR) confirmed the altered expression of many of the genes that were affected differently in the fluoroquinolone-resistant mutants and wild types. The levels of gene expression and enzyme production for the toxins phospholipase C, perfringolysin O, collagenase and clostripain had decreased in 13124R and increased in NCTRR in comparison with the wild types. After centrifugation, the cytotoxicity of the supernatants of NCTRR and 13224R cultures for mouse peritoneal macrophages confirmed the increased cytotoxicity of NCTRR and the decreased cytotoxicity of 13124R in comparison with the respective wild types. Fluoroquinolone resistance selection also affected cell shape and colony morphology in both strains. Conclusion Our results indicate that gatifloxacin resistance selection was associated with altered gene expression in two C. perfringens strains and that the effect was strain-specific. This study clearly demonstrates that bacterial exposure to fluoroquinolones may affect virulence (toxin production) in addition to drug resistance. PMID:23452396

2013-01-01

113

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

114

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

115

Expression Profiles of Genes in Toll-Like Receptor-Mediated Signaling of Broilers Infected with Clostridium perfringens?  

PubMed Central

Toll-like receptors (TLRs) participate in detecting microbial pattern molecules for activation of the host immune response. We investigated possible roles of TLRs in the chicken response to Clostridium perfringens infection by examining the expression of TLR genes and other genes involved in TLR-mediated signaling within the spleens and ilea of C. perfringens-challenged broilers. Upregulation of a tumor necrosis factor alpha-inducing factor homolog in challenged chickens compared to naïve chickens was observed, regardless of the incidence of necrotic enteritis. In addition, the members of the TLR2 subfamily were found to be most strongly involved in the host response to C. perfringens challenge, although the expression of TLR4 and TLR7 was also upregulated in spleen tissues. While the combination of TLR1.2, TLR2.1, and TLR15 appeared to play a major role in the splenic response, the expression of TLR2.2 and TLR1.1 was positively correlated to the expression of adaptor molecules MyD88, TRAF6, TRIF, and receptor interacting protein 1 in the ileal tissues, demonstrating a dynamic spatial and temporal innate host response to C. perfringens. PMID:19776194

Lu, Yang; Sarson, Aimie J.; Gong, Joshua; Zhou, Huaijun; Zhu, Weiyun; Kang, Zhumei; Yu, Hai; Sharif, Shayan; Han, Yanming

2009-01-01

116

Fast kinetics of nucleotide binding to Clostridium perfringens family II pyrophosphatase containing CBS and DRTGG domains.  

PubMed

We earlier described CBS-pyrophosphatase of Moorella thermoacetica (mtCBS-PPase) as a novel phosphohydrolase that acquired a pair of nucleotide-binding CBS domains during evolution, thus endowing the protein with the capacity to be allosterically regulated by adenine nucleotides (Jämsen, J., Tuominen, H., Salminen, A., Belogurov, G. A., Magretova, N. N., Baykov, A. A., and Lahti, R. (2007) Biochem. J., 408, 327-333). We herein describe a more evolved type of CBS-pyrophosphatase from Clostridium perfringens (cpCBS-PPase) that additionally contains a DRTGG domain between the two CBS domains in the regulatory part. cpCBS-PPase retained the ability of mtCBS-PPase to be inhibited by micromolar concentrations of AMP and ADP and activated by ATP and was additionally activated by diadenosine polyphosphates (AP(n)A) with n > 2. Stopped-flow measurements using a fluorescent nucleotide analog, 2'(3')-O-(N-methylanthranoyl)-AMP, revealed that cpCBS-PPase interconverts through two different conformations with transit times on the millisecond scale upon nucleotide binding. The results suggest that the presence of the DRTGG domain affords greater flexibility to the regulatory part, allowing it to more rapidly undergo conformational changes in response to binding. PMID:22348476

Jämsen, J; Baykov, A A; Lahti, R

2012-02-01

117

Excitatory effect of Clostridium perfringens alpha toxin on the rat isolated aorta.  

PubMed Central

Clostridium perfringens alpha toxin caused contraction of the isolated aorta of the rat in a dose-dependent manner. The contractile action caused by the toxin was inhibited or abolished by calcium antagonists such as nifedipine, verapamil and cinnarizine, or a Ca-free medium, but was not affected by phentolamine, chlorpheniramine, atropine, tetrodotoxin or a low Na medium. The toxin stimulated Ca uptake into the aorta in a dose-dependent manner. 8-N,N'-diethylaminooctyl-3,4,5-trimethoxybenzoate (TMB-8) blocked significantly both the toxin- and noradrenaline (NA)-induced contractions. Trifluoperazine (TFP) and N-(6-aminohexyl)-5-chloro-1-naphtharene sulphonamide (W-7) did not affect the contractile activity of the toxin but blocked the NA-induced contraction. The toxin also stimulated the 32P phosphate labelling of phosphatidylinositol (PI) and phosphatidic acid (PA) in the preparation. These results indicate that the toxin-induced contraction, which is different from that induced by NA, is the result of a direct action of the toxin on the aorta and is due to an increased Ca2+ permeability across the smooth muscle membrane. It is suggested that the contractile response to the toxin is associated with activation of phospholipid metabolism and enhanced entry of Ca into the aorta. Images Figure 1 PMID:3742149

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

1986-01-01

118

Esterase electrophoretic polymorphism of human and animal strains of Clostridium perfringens.  

PubMed Central

Esterase electrophoretic polymorphism in human and animal strains of Clostridium perfringens was studied by using polyacrylamide-agarose gel electrophoresis. Five types of esterases, designated E-I to E-V and defined by their hydrolytic specificities toward five synthetic substrates, were found in protein extracts of bacteria grown without glucose (glucose-containing media allowed only the expression of esterase E-I). Mobility variants of esterase E-I, which hydrolyzes alpha- and beta-naphthyl acetates and butyrates, were used as a basis for the distribution of strains into 11 zymogroups. When all five types of esterases and their electrophoretic variants were considered, 77 electrophoretic types (ETs) could be described for the 89 strains tested. Animal strains did not constitute a distinctive subpopulation, as revealed by their distribution in the zymogroups and by clustering analysis. Statistical analysis also emphasized the importance of esterase E-IV (which hydrolyzes only naphthyl acetates) and esterase E-V (which hydrolyzes only alpha-naphthyl acetate) in clustering by the relatedness of the ETs. ETs allowed the epidemiological characterization of stool isolates recovered from elderly inpatient residents and from adolescent chronic-care psychiatric patients. These results indicate that esterase electrophoretic typing may be a marker for epidemiological and ecological analyses. PMID:8434914

Pons, J L; Picard, B; Niel, P; Leluan, G; Goullet, P

1993-01-01

119

Esterase electrophoretic polymorphism of human and animal strains of Clostridium perfringens.  

PubMed

Esterase electrophoretic polymorphism in human and animal strains of Clostridium perfringens was studied by using polyacrylamide-agarose gel electrophoresis. Five types of esterases, designated E-I to E-V and defined by their hydrolytic specificities toward five synthetic substrates, were found in protein extracts of bacteria grown without glucose (glucose-containing media allowed only the expression of esterase E-I). Mobility variants of esterase E-I, which hydrolyzes alpha- and beta-naphthyl acetates and butyrates, were used as a basis for the distribution of strains into 11 zymogroups. When all five types of esterases and their electrophoretic variants were considered, 77 electrophoretic types (ETs) could be described for the 89 strains tested. Animal strains did not constitute a distinctive subpopulation, as revealed by their distribution in the zymogroups and by clustering analysis. Statistical analysis also emphasized the importance of esterase E-IV (which hydrolyzes only naphthyl acetates) and esterase E-V (which hydrolyzes only alpha-naphthyl acetate) in clustering by the relatedness of the ETs. ETs allowed the epidemiological characterization of stool isolates recovered from elderly inpatient residents and from adolescent chronic-care psychiatric patients. These results indicate that esterase electrophoretic typing may be a marker for epidemiological and ecological analyses. PMID:8434914

Pons, J L; Picard, B; Niel, P; Leluan, G; Goullet, P

1993-02-01

120

Sialidase Production and Genetic Diversity in Clostridium perfringens Type A Isolated from Chicken with Necrotic Enteritis in Brazil.  

PubMed

The sialidase activity and genetic diversity of 22 Clostridium perfringens strains isolated from chickens with necrotic enteritis were determined. Sialidase activity was detected in 86.4 % of the strains. All C. perfringens showed a high value of similarity (>96 %), and they were grouped into seven clusters clearly separated from the other reference bacterial strains. From these clusters four patterns were defined in accordance with their phenotypic (sialidase production and antibiotic resistance profile) and genotypic (presence of nanI and nanJ genes) characteristics. Our results showed heterogeneity among strains, but they were genotypically similar, and it is suggested further studies are needed to better understand the pathogenesis of necrotic enteritis. PMID:25373329

Llanco, Luis A; Nakano, Viviane; Avila-Campos, Mario J

2015-03-01

121

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

122

Bacillus subtilis PB6 improves intestinal health of broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis.  

PubMed

Necrotic enteritis (NE) is an enterotoxemic disease caused by Clostridium perfringens that results in significant economic losses, averaging damage of $0.05 per bird. The present study investigated the influence of a dietary supplement, Bacillus subtilis PB6, on performance, intestinal health, and gut integrity against C. perfringens-induced NE in broiler birds. Bacillus subtilis PB6 (ATCC-PTA 6737) is a natural strain isolated from healthy chicken gut that has been shown in in vitro to produce antimicrobial substances with broad activity against various strains of Campylobacter and Clostridium species. The animal study was conducted on broiler chickens (Cobb 400) for the period of 35 d using a completely randomized design. The experimental design included 3 treatments groups. Each treatment group contained 6 replicates, 3 male and 3 female, with 12 birds in each replicate. The 3 treatment groups were an uninfected control, an infected control, and an infected group supplemented with B. subtilis PB6 at 500 g/t of feed, containing 5 × 10(11) cfu/kg. Necrotic enteritis was induced in the broiler birds via oral inoculation of 30,000 oocysts of mixed strains of Eimeria species on d 14 followed by C. perfringens (10(8) cfu/mL) on d 19 through 21 of trial. The birds were analyzed for BW gain, mortality, feed conversion ratio (FCR), intestinal lesion score, intestinal C. perfringens counts, and villus histomorphometry. The infected control group showed markedly thickened mucosa, hemorrhages, intestinal lesions, and ballooning of intestine. The supplementation of B. subtilis PB6 reduced the FCR (P < 0.05) and intestinal C. perfringens counts significantly (P < 0.05) compared with the infected control group. It was also observed that B. subtilis PB6 improved villi length by 10.88 and 30.46% (P < 0.05) compared with uninfected and infected control groups, respectively. The group supplemented with B. subtilis PB6 significantly (P < 0.05) increased the villi length to crypt depth ratio by 49.11% compared with the infected group. In conclusion, the supplementation of B. subtilis PB6 not only controlled C. perfringens-induced NE, but also improved intestinal health in the broiler birds. PMID:23300303

Jayaraman, Sathishkumar; Thangavel, Gokila; Kurian, Hannah; Mani, Ravichandran; Mukkalil, Rajalekshmi; Chirakkal, Haridasan

2013-02-01

123

Efficacy of a lactylate on production performance and intestinal health of broilers during a subclinical Clostridium perfringens infection.  

PubMed

Clostridium perfringens, an ?-toxin producing gram-positive bacterium, is an enteric pathogen for poultry. Because subclinical C. perfringens infections often result in damage of the intestinal mucosa, decreased nutrient digestion, and poor performance, efforts should be taken to find an effective strategy that controls overgrowth of C. perfringens. For this purpose, the efficacy of a sodium lauroyl lactylate (LauL) as a feed additive to prevent C. perfringens colonization in broilers was determined. First, the effect of LauL was compared with capric and lauric mono- and diglycerides (MDG) and capric and lauric free fatty acids in Clostridium-infected chickens. Clostridial lesion scoring at d 16 showed that MDG and LauL were both effective in reducing the severity of lesions. When taking into account results on BW gain and mortality, LauL was more effective than MDG. For this reason, a dose response study was made to determine the optimal dietary dosage of LauL. In this experiment, it was shown that a LauL dose higher than 0.15% should be used to expect positive effects on lesion severity and mortality. None of the LauL doses led to a significant better response on growth performance. In a third trial, efficacy of LauL was compared with commercial products that limit bacterial activity in the intestinal tract (Aromabiotic Poul 60) or coccidiosis (chemical coccidiostat, Clinacox). None of the products were able to reduce the number or severity of lesions, and no effect on production performance was observed. Thus, despite the clear positive effect seen in experiment 1, and in experiment 2 with LauL doses higher than 0.15%, supplementing this lactylate to the diet does not consistently reduce C. perfringens colonization in broiler chickens because no such effects were observed in experiment 3. These results, however, provide a scientific basis for future studies to further investigate lactylates as potential additives to reduce the severity of necrotic enteritis in broilers in a C. perfringens challenge model. PMID:20952703

Lensing, M; van der Klis, J D; Fabri, T; Cazemier, A; Else, A J

2010-11-01

124

Rubrerythrin from Clostridium perfringens: cloning of the gene, purification of the protein, and characterization of its superoxide dismutase function.  

PubMed Central

The food-borne pathogen Clostridium perfringens, which is an obligate anaerobe, showed growth under conditions of oxidative stress. In protein extracts we looked for superoxide dismutase (SOD) activities which might scavenge highly toxic superoxide radicals evolving under such stress conditions. Using the classical assay to detect SOD activity on gels after electrophoresis of C. perfringens proteins, we obtained a pattern of three major bands indicating SOD activity. The protein representing the brightest band was purified by three chromatographic steps. On the basis of 20 amino acids determined from the N terminus of the protein, we designed a degenerate oligonucleotide probe to isolate the corresponding gene. We finally sequenced an open reading frame of 195 amino acids (molecular mass, 21,159 Da) with a strong homology to the Desulfovibrio vulgaris rubrerythrin; therefore, we assumed to have cloned a rubrerythrin gene from C. perfringens, and we named it rbr. The C-terminal region of the newly detected rubrerythrin from C. perfringens contains a characteristic non-heme, non-sulfur iron-binding site -Cys-X-X-Cys-(X)12-Cys-X-X-Cys- similar to that found in rubrerythrin from D. vulgaris. In addition, three -Glu-X-X-His- sequences could represent diiron binding domains. We observed SOD activity in extracts of Escherichia coli strains containing the recombinant rbr gene from C. perfringens. A biological function of rubrerythrin as SOD was confirmed with the functional complementation by the rbr gene of an E. coli mutant strain lacking SOD activity. We therefore suppose that rubrerythrin plays a role as a scavenger of oxygen radicals. PMID:8955396

Lehmann, Y; Meile, L; Teuber, M

1996-01-01

125

Control of Clostridium perfringens spores by green tea leaf extracts during cooling of cooked ground beef, chicken, and pork.  

PubMed

We investigated the inhibition of Clostridium perfringens spore germination and outgrowth by two green tea extracts with low (green tea leaf powder [GTL]; 141 mg of total catechins per g of green tea extract) and high (green tea leaf extract [GTE]; 697 mg of total catechins per g of extract) catechin levels during abusive chilling of retail cooked ground beef, chicken, and pork. Green tea extracts were mixed into the thawed beef, chicken, and pork at concentrations of 0.5, 1.0, and 2.0% (wt/ wt), along with a heat-activated (75 degrees C for 20 min) three-strain spore cocktail to obtain a final concentration of approximately 3 log spores per g. Samples (5 g) of the ground beef, chicken, and pork were then vacuum packaged and cooked to 71 degrees C for 1 h in a temperature-controlled water bath. Thereafter, the products were cooled from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h, resulting in significant increases (P < 0.05) in the germination and outgrowth of C. perfringens populations in the ground beef, chicken, and pork control samples without GTL or GTE. Supplementation with 0.5 to 2% levels of GTL did not inhibit C. perfringens growth from spores. In contrast, the addition of 0.5 to 2% levels of GTE to beef, chicken, and pork resulted in a concentration-and time-dependent inhibition of C. perfringens growth from spores. At a 2% level of GTE, a significant (P < 0.05) inhibition of growth occurred at all chill rates for cooked ground beef, chicken, and pork. These results suggest that widely consumed catechins from green tea can reduce the potential risk of C. perfringens spore germination and outgrowth during abusive cooling from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h of cooling for ground beef, chicken, and pork. PMID:17612073

Juneja, Vijay K; Bari, M L; Inatsu, Y; Kawamoto, S; Friedman, Mendel

2007-06-01

126

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

127

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

128

Endo-N-acetyl-glucosaminidase from Clostridium perfringens, lytic for cell wall murein of gram-negative bacteria.  

PubMed

An endo-N-acetyl-glucosaminidase which degrades the murein (peptidoglycan) sacculi of the cell walls of Escherichia coli and Spirillum serpens, but not those of Micrococcus lysodeikticus and Sarcina lutea, is present as a contaminant in a "phospholipase C" from Clostridium perfringens. The specificity of enzyme action was elucidated by reduction of liberated glycosidic groups with NaBH(4) and identification of glucosaminol as the reduction product. This finding contradicts previous reports associating cell wall breakdown with specific phospholipase action. PMID:4315891

Martin, H H; Kemper, S

1970-05-01

129

The Site of Vascular Response to the ?-Toxin of Clostridium Perfringens Type A in Skeletal Muscle  

PubMed Central

The vascular response to the ?-toxin of Clostridium perfringens type A, was observed topographically in the cremaster muscle of the rat, in terms of exudation, labelling of damaged vessels by circulating carbon, and in addition histologically for patency of the vascular plexus. It was confirmed that the permeability response is biphasic. The short-lived immediate phase corresponds to that of venular labelling, and the delayed phase reaches its peak rather later than the corresponding phase of capillary labelling. The intensity and extent of these responses are determined by the degree of injury, but their shape and timing, especially in the immediate phase, vary almost as consistently with the duration of exposure to circulating dye or carbon. After the standard dose of toxin, vascular patency is largely unaffected until 24 hours. Apparently irreversible vascular occlusion occurs rather earlier with larger doses. A three-fold reduction of the standard dose proportionately reduces both exudation and capillary labelling but leaves immediate venular labelling unaffected, suggesting that the latter is not dose dependent and therefore non-specific. Prolongation of moderate venular labelling into the middle of the delayed phase may occur at this dosage. Its absence after the standard dose suggests that delayed inhibition of venular reactivity may be occurring. Irregular labelling of venules and small veins persists throughout the delayed phase with doses 2·4 or more times the standard dose. A brief ultramicroscopic survey revealed appearances in both venules and capillaries at 1-2 hours after injury closely comparable to those which have been described for Cl. oedematiens toxin at 6-24 hours. In rats given carbon during the delayed phase, the effective vascular patency 10 minutes later includes half of the labelled capillaries up to 10 ?m in diameter. This proportion is little affected by toxin dose, but intensely so when the carbon clearance time is increased, suggesting that such injured microvessels may be a major source of plasma protein exudation. ImagesFig. 1Fig. 2 PMID:4341798

Wells, F. R.

1972-01-01

130

Structure and stability of an azoreductase with an FAD cofactor from the strict anaerobe Clostridium perfringens.  

PubMed

Azoreductase enzymes present in many microorganisms exhibit the ability to reduce azo dyes, an abundant industrial pollutant, to produce carcinogenic metabolites that threaten human health. All biochemically-characterized azoreductases, around 30 to date, have been isolated from aerobic bacteria, except for AzoC, the azoreductase of Clostridium perfringens, which is from a strictly anaerobic bacterium. AzoC is a recently biochemically-characterized azoreductase. The lack of structural information on AzoC hinders the mechanistic understanding of this enzyme. In this paper, we report on the biophysical characterization of the structure and thermal stability of AzoC by using a wide range of biophysical tools: Liquid Chromatography-Mass Spectrometry (LC-MS), Circular Dichroism Spectroscopy, Fourier-transform Infrared (FTIR) Spectroscopy, SDS-PAGE, Size Exclusion Chromatography, MALDI-TOF and UV-visible spectroscopy. We found that the flavin cofactor of AzoC is FAD, while all other structurally-known azoreductases employ FMN as a cofactor. The secondary structure of AzoC has 16% less ?-helix structures, 5% more ?-sheet structures and 11% more turn and unordered than the average of structurally-known azoreductase that have 10-14% sequence similarities with AzoC. We also found that oxidized AzoC is trimeric, which is unique amongst structurally known azoreductases. In contrast, reduced AzoC is monomeric, despite similarities in catalytic activity and thermal stability of oxidized and reduced AzoC. Our results show that the use of FTIR spectroscopy is crucial for characterization of the ?-sheet content in AzoC, illustrating the need for complementary biophysical tools for secondary structural characterization of proteins. PMID:24779771

Morrison, Jessica; Dai, Shuo; Ren, Jie; Taylor, Amanda; Wilkerson, Mitchell; John, Gilbert; Xie, Aihua

2014-06-01

131

Functional Identification of Conjugation and Replication Regions of the Tetracycline Resistance Plasmid pCW3 from Clostridium perfringens  

PubMed Central

Clostridium perfringens causes fatal human infections, such as gas gangrene, as well as gastrointestinal diseases in both humans and animals. Detailed molecular analysis of the tetracycline resistance plasmid pCW3 from C. perfringens has shown that it represents the prototype of a unique family of conjugative antibiotic resistance and virulence plasmids. We have identified the pCW3 replication region by deletion and transposon mutagenesis and showed that the essential rep gene encoded a basic protein with no similarity to any known plasmid replication proteins. An 11-gene conjugation locus containing 5 genes that encoded putative proteins with similarity to proteins from the conjugative transposon Tn916 was identified, although the genes’ genetic arrangements were different. Functional genetic studies demonstrated that two of the genes in this transfer clostridial plasmid (tcp) locus, tcpF and tcpH, were essential for the conjugative transfer of pCW3, and comparative analysis confirmed that the tcp locus was not confined to pCW3. The conjugation region was present on all known conjugative plasmids from C. perfringens, including an enterotoxin plasmid and other toxin plasmids. These results have significant implications for plasmid evolution, as they provide evidence that a nonreplicating Tn916-like element can evolve to become the conjugation locus of replicating plasmids that carry major virulence genes or antibiotic resistance determinants. PMID:16788202

Bannam, Trudi L.; Teng, Wee Lin; Bulach, Dieter; Lyras, Dena; Rood, Julian I.

2006-01-01

132

Characterization of a bacteriocinogenic plasmid from Clostridium perfringens and molecular genetic analysis of the bacteriocin-encoding gene.  

PubMed Central

The bacteriocinogenic plasmid pIP404 from Clostridium perfringens was isolated and cloned in Escherichia coli, and its physical map was deduced. Expression of the bcn gene, encoding bacteriocin BCN5, is inducible by UV irradiation of C. perfringens and thus resembles the SOS-regulated bacteriocin genes of enteric bacteria. The location of bcn on pIP404 was established by a dot-blot procedure, using specific hybridization probes to analyze mRNA samples from induced and uninduced cultures. From the nucleotide sequence of its gene, the molecular weight of BCN5 was deduced to be 96,591, and a protein of this size was secreted by bacteriocin-producing cultures of C. perfringens. The primary structure of the protein suggests that it may function as an ionophore, since a hydrophobic domain, resembling those of the ionophoric colicins, is present at the COOH terminus. No bacteriocin activity could be detected in E. coli harboring plasmids bearing the bcn gene, even when the transcriptional and translational signals were replaced by those of lacZ. A possible explanation may be found in the unusual codon usage of the adenine-thymine-rich bcn gene, as this shows a preference for codons with a high adenine-plus-thymine content, especially in the wobble position. Many of the frequently used codons correspond to those recognized by minor tRNA species in E. coli. Consequently, bcn expression might be limited by tRNA availability in this bacterium. Images PMID:2877971

Garnier, T; Cole, S T

1986-01-01

133

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

134

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

135

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

136

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

137

CLOSTRIDIUM PERFRINGENS TYPE A ENTEROTOXEMIA IN A CAPTIVE ADULT WHITE-TAILED DEER --On the morning of 6 June 2005, a captive adult  

E-print Network

197 CLOSTRIDIUM PERFRINGENS TYPE A ENTEROTOXEMIA IN A CAPTIVE ADULT WHITE-TAILED DEER -- On the morning of 6 June 2005, a captive adult white-tailed deer (Odocoileus virginianus) was found dead at the South Dakota State University (SDSU) Wildlife Research Facility, where a captive deer herd of approxi

138

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  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 5C for 3 or...

139

Inhibition of clostridium perfringens spore germination and outgrowth by buffered vinegar and lemon juice concentrate during chilling.....of ground turkey road containing minimal ingredients  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inhibition of Clostridium perfringens spore germination and outgrowth in ground turkey roast containing minimal ingredients (salt and sugar), by buffered vinegar (MoStatin V) and a blend (buffered) of lemon juice concentrate and vinegar (MoStatin LV) was evaluated. Ground turkey roast was formulat...

140

VIABILITY OF CLOSTRIDIUM PERFRINGENS, ESCHERICHIA COLI, AND LISTERIA MONOCYTOGNES SURVIVING MILD HEAT OR AQUEOUS OZONE TREATMENT ON BEEF FOLLOWED BY HEAT, ALKALI, OR SALT STRESS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The threat of pathogen survival following ozone treatment of meat necessitates careful evaluation of the surviving microorganisms for tolerance to subsequent heat, pH, and NaCl stress. Log reductions in CFU/g of 3-strain cocktails of Clostridium perfringens, Escherichia coli O157:H7, and Listeria m...

141

Clostridium Perfringens a-Toxin and NetB Toxin Antibodies and their possible role in protection against Necrotic Enteritis and Gangrenous Dermatitis in broiler chickens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Necrotic enteritis (NE) and gangrenous dermatitis (GD) are important infectious diseases of poultry. Although NE and GD share a common pathogen, Clostridium perfringens, they differ in other important aspects, such as clinical signs, pathologic symptoms, and age of onset. The primary virulence facto...

142

PREDICTIVE MODEL FOR GROWTH OF CLOSTRIDIUM PERFRINGENS IN ROAST BEEF DURING COOLING AND INHIBITION OF SPORE GERMINATION AND OUTGROWTH BY SALTS OF ORGANIC ACIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Germination and outgrowth of Clostridium perfringens spores in roast beef during chilling was studied following simulated cooling schedules normally used in the processed meat industry. Beef top rounds were formulated to contain a marinade (finished product concentrations of salt, 1%; potassium tet...

143

Inhibition of Clostridium perfringens spore germination and outgrowth by lemon juice and vinegar product in reduced NaCl roast beef  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inhibition of Clostridium perfringens spore germination and outgrowth in reduced sodium roast beef by a blend of buffered lemon juice concentrate and vinegar (MoStatin LV) during abusive exponential cooling was evaluated. Roast beef containing salt (NaCl; 1, 1.5, or 2%, wt/wt), blend of sodium pyro-...

144

Immunopathology and Cytokine Responses in Broiler Chickens Coinfected with Eimeria maxima and Clostridium perfringens Using an Animal Model of Necrotic Enteritis  

Technology Transfer Automated Retrieval System (TEKTRAN)

The incidence of necrotic enteritis (NE) due to Clostridium perfringens (CP) infection in commercial poultry has been increasing at an alarming rate. While pre-exposure of chickens to coccidia infections is believed to be one of the major risk factors leading to NE, the underlying mechanisms of CP ...

145

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

146

tISCpe8, an IS1595-Family Lincomycin Resistance Element Located on a Conjugative Plasmid in Clostridium perfringens?  

PubMed Central

Clostridium perfringens is a normal gastrointestinal organism that is a reservoir for antibiotic resistance genes and can potentially act as a source from which mobile elements and their associated resistance determinants can be transferred to other bacterial pathogens. Lincomycin resistance in C. perfringens is common and is usually encoded by erm genes that confer macrolide-lincosamide-streptogramin B resistance. In this study we identified strains that are lincomycin resistant but erythromycin sensitive and showed that the lincomycin resistance determinant was plasmid borne and could be transferred to other C. perfringens isolates by conjugation. The plasmid, pJIR2774, is the first conjugative C. perfringens R-plasmid to be identified that does not confer tetracycline resistance. Further analysis showed that resistance was encoded by the lnuP gene, which encoded a putative lincosamide nucleotidyltransferase and was located on tISCpe8, a functional transposable genetic element that was a member of the IS1595 family of transposon-like insertion sequences. This element had significant similarity to the mobilizable lincomycin resistance element tISSag10 from Streptococcus agalactiae. Like tISSag10, tISCpe8 carries a functional origin of transfer within the resistance gene, allowing the element to be mobilized by the conjugative transposon Tn916. The similarity of these elements and the finding that they both contain an oriT-like region support the hypothesis that conjugation may result in the movement of DNA modules that are not obviously mobile since they are not linked to conjugation or mobilization functions. This process likely plays a significant role in bacterial adaptation and evolution. PMID:19684139

Lyras, Dena; Adams, Vicki; Ballard, Susan A.; Teng, Wee L.; Howarth, Pauline M.; Crellin, Paul K.; Bannam, Trudi L.; Songer, J. Glenn; Rood, Julian I.

2009-01-01

147

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, Na?asa; Scherer, Siegfried; Loessner, Martin J.

2002-01-01

148

Control of Clostridium perfringens germination and outgrowth by buffered sodium citrate during chilling of roast beef and injected pork.  

PubMed

Inhibition of the germination and outgrowth of Clostridium perfringens by buffered sodium citrate (Ional) and buffered sodium citrate supplemented with sodium diacetate (Ional Plus) during the abusive chilling of roast beef and injected pork was evaluated. Beef top rounds or pork loins were injected with a brine containing NaCl, potato starch, and potassium tetrapyrophosphate to yield final in-product concentrations of 0.85, 0.25, and 0.20%, respectively. Products were ground and mixed with Ional or Ional Plus at 0, 0.5, 1.0, and 2.0%. Each product was mixed with a three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.5 log10 spores per g. Chilling of roast beef from 54.4 to 7.2 degrees C resulted in C. perfringens population increases of 1.51 and 5.27 log10 CFU/g for 18- and 21-h exponential chill rates, respectively, while chilling of injected pork resulted in increases of 3.70 and 4.41 log10 CFU/g. The incorporation of Ional into the roast beef formulation resulted in C. perfringens population reductions of 0.98, 1.87, and 2.47 log10 CFU/g with 0.5, 1.0, and 2.0% Ional, respectively, over 18 h of chilling, while > or = 1.0% Ional Plus was required to achieve similar reductions (reductions of 0.91 and 2.07 log10 CFU/g were obtained with 1.0 and 2.0% Ional Plus, respectively). An Ional or Ional Plus concentration of > or = 1.0% was required to reduce C. perfringens populations in roast beef or injected pork chilled from 54.4 to 7.2 degrees C in 21 h. Cooling times for roast beef or injected pork products after heat processing can be extended to 21 h through the incorporation of > or = 1.0% Ional or Ional Plus into the formulation to reduce the potential risk of C. perfringens germination and outgrowth. PMID:12636288

Thippareddi, H; Juneja, V K; Phebus, R K; Marsden, J L; Kastner, C L

2003-03-01

149

Clostridium perfringens challenge and dietary fat type affect broiler chicken performance and fermentation in the gastrointestinal tract.  

PubMed

The aim of the present work was to examine how different fats commonly used in the feed industry affect broiler performance, nutrient digestibility and microbial fermentation in the gastrointestinal tract of broiler chickens challenged with virulent Clostridium perfringens strains. Two experiments were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C. perfringens did not affect broiler chicken body weight gain (BWG) and mortality in either of the two experiments. The BWG was affected by dietary fat type in both experiments, indicating that the fatty acid composition of the fat source affects broiler growth performance. In particular, the inclusion of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v. 1.69) and at 42 days (1.65 v. 1.68). In both experiments apparent metabolizable energy values were affected by dietary fat type. Irrespective of the fat type present in the diet, C. perfringens challenge decreased the digesta pH in the crop and ileum, but had no effect in cecal contents. Moreover, in Experiment 1, total organic acid concentration in the ileum was two to three times lower on soybean oil diets as compared with other treatments, indicating that C. perfringens as well as dietary fat type significantly affects microbiota activity in the broiler chicken gastrointestinal tract. PMID:24674938

Józefiak, D; Kiero?czyk, B; Rawski, M; Hejdysz, M; Rutkowski, A; Engberg, R M; Højberg, O

2014-06-01

150

A Wide Variety of Clostridium perfringens Type A Food-Borne Isolates That Carry a Chromosomal cpe Gene Belong to One Multilocus Sequence Typing Cluster  

PubMed Central

Of 98 suspected food-borne Clostridium perfringens isolates obtained from a nationwide survey by the Food and Consumer Product Safety Authority in The Netherlands, 59 strains were identified as C. perfringens type A. Using PCR-based techniques, the cpe gene encoding enterotoxin was detected in eight isolates, showing a chromosomal location for seven isolates and a plasmid location for one isolate. Further characterization of these strains by using (GTG)5 fingerprint repetitive sequence-based PCR analysis distinguished C. perfringens from other sulfite-reducing clostridia but did not allow for differentiation between various types of C. perfringens strains. To characterize the C. perfringens strains further, multilocus sequence typing (MLST) analysis was performed on eight housekeeping genes of both enterotoxic and non-cpe isolates, and the data were combined with a previous global survey covering strains associated with food poisoning, gas gangrene, and isolates from food or healthy individuals. This revealed that the chromosomal cpe strains (food strains and isolates from food poisoning cases) belong to a distinct cluster that is significantly distant from all the other cpe plasmid-carrying and cpe-negative strains. These results suggest that different groups of C. perfringens have undergone niche specialization and that a distinct group of food isolates has specific core genome sequences. Such findings have epidemiological and evolutionary significance. Better understanding of the origin and reservoir of enterotoxic C. perfringens may allow for improved control of this organism in foods. PMID:22865060

Xiao, Yinghua; Wagendorp, Arjen; Moezelaar, Roy; Abee, Tjakko

2012-01-01

151

Detection of toxins A/B and isolation of Clostridium difficile and Clostridium perfringens from dogs in Minas Gerais, Brazil.  

PubMed

The objective of this study was to detect C. difficile A/B toxins and to isolate strains of C. perfringens and C. difficile from diarrheic and non-diarrheic dogs in Brazil. Stool samples were collected from 57 dogs, 35 of which were apparently healthy, and 22 of which were diarrheic. C. difficile A/B toxins were detected by ELISA, and C. perfringens and C. difficile were identified by multiplex PCR. C. difficile A/B toxins were detected in 21 samples (36.8%). Of these, 16 (76.2%) were from diarrheic dogs, and five (23.8%) were from non-diarrheic dogs. Twelve C. difficile strains (21.1%) were isolated, of which ten were A(+)B(+) and two were A(-)B(-). All non-toxigenic strains were isolated from non-diarrheic animals. The binary toxin gene cdtB was found in one strain, which was A(+)B(+) and was derived from a non-diarrheic dog. C. perfringens strains were isolated from 40 samples (70.2%). Of these, 18 (45%) were from the diarrheic group, and 22 (55%) belonged to the non-diarrheic group. All isolates were classified as C. perfringens type A and there was an association between the detection of the cpe gene and the presence of diarrhea. Interestingly, ten strains (25%) were positive for the presence of the cpb2 gene. The high rate of detection of the A/B toxins in non-diarrheic dogs suggests the occurrence of subclinical disease in dogs or carriage of its toxins without disease. More studies are needed to elucidate the epidemiology of C. difficile and C. perfringens in dogs and to better our understanding of C. difficile as a zoonotic agent. This is the first study to report the binary toxin gene in C. difficile strains isolated from dogs in Brazil. PMID:24159295

Silva, Rodrigo Otávio Silveira; Santos, Renata Lara Resende; Pires, Prhiscylla Sadanã; Pereira, Luiz Carlos; Pereira, Silvia Trindade; Duarte, Marina Carvalho; de Assis, Ronnie Antunes; Lobato, Francisco Carlos Faria

2013-01-01

152

Hypermotility in Clostridium perfringens Strain SM101 Is Due to Spontaneous Mutations in Genes Linked to Cell Division  

PubMed Central

Clostridium perfringens is a Gram-positive anaerobic pathogen of humans and animals. Although they lack flagella, C. perfringens bacteria can still migrate across surfaces using a type of gliding motility that involves the formation of filaments of bacteria lined up in an end-to-end conformation. In strain SM101, hypermotile variants are often found arising from the edges of colonies on agar plates. Hypermotile cells are longer than wild-type cells, and video microscopy of their gliding motility suggests that they form long, thin filaments that move rapidly away from a colony, analogously to swarmer cells in bacteria with flagella. To identify the cause(s) of the hypermotility phenotype, the genome sequences of normal strains and their direct hypermotile derivatives were determined and compared. Strains SM124 and SM127, hypermotile derivatives of strains SM101 and SM102, respectively, contained 10 and 6 single nucleotide polymorphisms (SNPs) relative to their parent strains. While SNPs were located in different genes in the two sets of strains, one feature in common was mutations in cell division genes, an ftsI homolog in strain SM124 (CPR_1831) and a minE homolog in strain SM127 (CPR_2104). Complementation of these mutations with wild-type copies of each gene restored the normal motility phenotype. A model explaining the principles underlying the hypermotility phenotype is presented. PMID:24748614

Liu, Hualan; McCord, Kristin D.; Howarth, Jonathon; Popham, David L.; Jensen, Roderick V.

2014-01-01

153

Structure of the food-poisoning Clostridium perfringens enterotoxin reveals similarity to the aerolysin-like pore-forming toxins  

PubMed Central

Clostridium perfringens enterotoxin (CPE) is a major cause of food poisoning and antibiotic-associated diarrhoea. Upon its release from C. perfringens spores, CPE binds to its receptor, claudin, at the tight junctions between the epithelial cells of the gut wall, and subsequently forms pores in the cell membranes. A number of different complexes between CPE and claudin have been observed and the process of pore-formation has not been fully elucidated. We have determined the 3D-structure of the soluble form of CPE in two crystal forms by X-ray crystallography, to a resolution of 2.7 and 4.0 Å respectively, and found that the N-terminal domain shows structural homology with the aerolysin-like ?-pore-forming family of proteins. We show that CPE forms a trimer in both crystal forms and that this trimer is likely to be biologically relevant but is not the active pore form. We use this data to discuss models of pore formation. PMID:21839091

Briggs, David C.; Naylor, Claire E.; Smedley, James G.; Lukoyanova, Natalya; Robertson, Susan; Moss, David S.; McClane, Bruce A.; Basak, Ajit K.

2011-01-01

154

Global Phenotypic Characterization of Effects of Fluoroquinolone Resistance Selection on the Metabolic Activities and Drug Susceptibilities of Clostridium perfringens Strains  

PubMed Central

Fluoroquinolone resistance affects toxin production of Clostridium perfringens strains differently. To investigate the effect of fluoroquinolone resistance selection on global changes in metabolic activities and drug susceptibilities, four C. perfringens strains and their norfloxacin-, ciprofloxacin-, and gatifloxacin-resistant mutants were compared in nearly 2000 assays, using phenotype microarray plates. Variations among mutant strains resulting from resistance selection were observed in all aspects of metabolism. Carbon utilization, pH range, osmotic tolerance, and chemical sensitivity of resistant strains were affected differently in the resistant mutants depending on both the bacterial genotype and the fluoroquinolone to which the bacterium was resistant. The susceptibilities to gentamicin and erythromycin of all resistant mutants except one increased, but some resistant strains were less susceptible to amoxicillin, cefoxitin, ceftriaxone, chloramphenicol, and metronidazole than their wild types. Sensitivity to ethidium bromide decreased in some resistant mutants and increased in others. Microarray analysis of two gatifloxacin-resistant mutants showed changes in metabolic activities that were correlated with altered expression of various genes. Both the chemical structures of fluoroquinolones and the genomic makeup of the wild types influenced the changes found in resistant mutants, which may explain some inconsistent reports of the effects of therapeutic use of fluoroquinolones on clinical isolates of bacteria. PMID:25587280

Park, Miseon

2014-01-01

155

NUMERICAL ANALYSIS OF THE GROWTH OF CLOSTRIDIUM PERFRINGENS IN COOKED BEEF UNDER ISOTHERMAL AND DYNAMIC CONDITIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to develop a mathematical methodology to estimate the growth of C. perfringens in cooked beef under dynamic temperature conditions. Two differential equations governing the lag phase development and cell multiplication were proposed and solved using a 4th-order Runge...

156

Dynamic determination of kinetic parameters and computer simulation of growth of Clostridium perfringens in cooked beef  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this research was to develop a new one-step methodology that uses a dynamic approach to directly construct a tertiary model for prediction of the growth of C. perfringens in cooked beef. This methodology was based on numerical analysis and optimization of both primary and secondary...

157

A novel watery diarrhoea caused by the co-infection of neonatal piglets with Clostridium perfringens type A and Escherichia coli (K88, 987P).  

PubMed

In 2011, a novel watery diarrhoea in 1-7 day-old piglets occurred in Changchun, China, characterized by high pathogenicity and mortality. Investigation of clinical signs, examination for viruses, and isolation and identification of bacteria showed that co-infection by Clostridium perfringens type A and Escherichia coli (K88, 987P) was the most likely cause of the disease. Newborn piglets challenged with a mixture of Clostridium perfringens type A and Escherichia coli (K88, 987P) died within 3 days with clinical signs and gross lesions similar to those in the piglets that died in the outbreak. A subsequent study showed that the use in sows of an inactivated vaccine against the two causal bacteria was effective at reducing the incidence of the watery diarrhoea in piglets. Piglets from sows given the inactivated vaccine had a incidence of watery diarrhoea of 8% (14/175), much lower than the 95% (192/201) seen in piglets from control sows. This is the first report of diarrhoea in piglets resulting from co-infection of Clostridium perfringens type A and Escherichia coli (K88, 987P). Further studies are required to better understand the pathogenesis of this disease. PMID:23846029

Wang, Xiaocen; Ren, Wenzhi; Nie, Ying; Cheng, Liqing; Tan, Wei; Wang, Chong; Wei, Libin; Zhang, Rui; Yan, Guangmou

2013-09-01

158

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

159

Dynamic determination of kinetic parameters, computer simulation, and probabilistic analysis of growth of Clostridium perfringens in cooked beef during cooling.  

PubMed

The objective of this research was to develop a new one-step methodology that uses a dynamic approach to directly construct a tertiary model for prediction of the growth of Clostridium perfringens in cooked beef. This methodology was based on simultaneous numerical analysis and optimization of both primary and secondary models using multiple dynamic growth curves obtained under different conditions. Once the models were constructed, the bootstrap method was used to calculate the 95% confidence intervals of kinetic parameters, and a Monte Carlo simulation method was developed to validate the models using the growth curves not previously used in model development. The results showed that the kinetic parameters obtained from this study accurately matched the common characteristics of C. perfringens, with the optimum temperature being 45.3°C. The results also showed that the predicted growth curves matched accurately with experimental observations used in validation. The mean of residuals of the predictions is -0.02logCFU/g, with a standard deviation of only 0.23logCFU/g. For relative growths <1logCFU/g, the residuals of predictions are <0.4logCFU/g. Overall, 74% of the residuals of predictions are <0.2logCFU/g, 7.7% are >0.4logCFU/g, while only 1.5% are >0.8logCFU/g. In addition, the dynamic model also accurately predicted four isothermal growth curves arbitrarily chosen from the literature. Finally, the Monte Carlo simulation was used to provide the probability of >1 and 2logCFU/g relative growths at the end of cooling. The results of this study will provide a new and accurate tool to the food industry and regulatory agencies to assess the safety of cooked beef in the event of cooling deviation. PMID:25500276

Huang, Lihan

2015-02-16

160

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

161

Two Novel Membrane Proteins, TcpD and TcpE, Are Essential for Conjugative Transfer of pCW3 in Clostridium perfringens.  

PubMed

The anaerobic pathogen Clostridium perfringens encodes either toxin genes or antibiotic resistance determinants on a unique family of conjugative plasmids that have a novel conjugation region, the tcp locus. Studies of the paradigm conjugative plasmid from C. perfringens, the 47-kb tetracycline resistance plasmid pCW3, have identified several tcp-encoded proteins that are involved in conjugative transfer and form part of the transfer apparatus. In this study, the role of the conserved hypothetical proteins TcpD, TcpE, and TcpJ was examined. Mutation and complementation analyses showed that TcpD and TcpE were essential for the conjugative transfer of pCW3, whereas TcpJ was not required. To analyze the TcpD and TcpE proteins in C. perfringens, functional hemagglutinin (HA)-tagged derivatives were constructed. Western blots showed that TcpD and TcpE localized to the cell envelope fraction independently of the presence of other pCW3-encoded proteins. Finally, examination of the subcellular localization of TcpD and TcpE by immunofluorescence showed that these proteins were concentrated at both poles of C. perfringens donor cells, where they are postulated to form essential components of the multiprotein complex that comprises the transfer apparatus. PMID:25488300

Wisniewski, Jessica A; Teng, Wee L; Bannam, Trudi L; Rood, Julian I

2015-02-15

162

Beta2 toxin is not involved in in vitro cell cytotoxicity caused by human and porcine cpb2-harbouring Clostridium perfringens.  

PubMed

Clostridium perfringens is a common cause of intestinal disease in animals and humans. Its pathogenicity is attributed to the toxins it can produce, including the beta2 toxin. The presence of cpb2, the gene encoding the beta2 toxin, has been associated with diarrhoea in neonatal piglets and humans. However, the exact role of the beta2 toxin in the development of diarrhoea is still unknown. In this study we investigated the level of cytotoxicity to porcine IPI-21 and human Caco-2 cell-lines caused by porcine and human cpb2-harbouring C. perfringens and the significance of the beta2 toxin for the induction of cell cytotoxicity. Supernatants of porcine cpb2-harbouring C. perfringens strains were cytotoxic to both cell lines. Cell cytotoxicity caused by supernatant of human cpb2-harbouring C. perfringens strains was variable among strains. However, removal of the beta2 toxin by anti-beta2 toxin antibodies or degradation of the beta2 toxin by trypsin did not reduce the cytotoxic effect of any of the supernatants. These data suggest that beta2 toxin does not play a role in the development of cell cytotoxicity in in vitro experiments. In vivo studies are necessary to definitely define the role of beta2 toxin in the development of cell cytotoxicity and subsequent diarrhoea. PMID:24768003

Allaart, Janneke G; van Asten, Alphons J A M; Vernooij, Johannes C M; Gröne, Andrea

2014-06-25

163

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

164

Inhibitory effects of organic acid salts on growth of Clostridium perfringens from spore inocula during chilling of marinated ground turkey breast.  

PubMed

Inhibition of Clostridium perfringens germination and outgrowth by salts of organic acids such as sodium lactate, sodium acetate, buffered sodium citrate and buffered sodium citrate supplemented with sodium diacetate was evaluated during continuous chilling of ground turkey. Turkey breast meat was injected with a brine-containing NaCl, potato starch and potassium tetra pyrophosphate to yield final in-product concentrations of 0.85%, 0.25% and 0.20%, respectively. The meat was ground, mixed with either sodium lactate (1%, 2%, 3% or 4%), sodium acetate (1% or 2%), buffered sodium citrate (Ional, 1%) or buffered sodium citrate supplemented with sodium diacetate (Ional Plus trade mark, 1%), in addition to a control that did not contain added antimicrobials. Each product was mixed with a three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.8 log10 spores/g. Inoculated products (10 g) were packaged into cook-in-bags (2 x 3 in.), vacuum sealed, cooked at 60 degrees C for 1 h, and subsequently chilled from 54.4 to 7.2 degrees C in 15, 18 and 21 h following exponential chilling rates. Products were sampled immediately after cooking and then after chilling. Chilling of cooked turkey following 15, 18 and 21 h chill rates resulted in germination and outgrowth of C. perfringens spores to 6.6, 7.58 and 7.95 log10 CFU/g populations, respectively, from initial spore populations of ca. 2.80 log10 CFU/g. Incorporation of sodium lactate (1%), sodium acetate (1%), Ional or Ional Plus (1%) substantially inhibited germination and outgrowth of C. perfringens spores compared to controls. Final C. perfringens total populations of 3.12, 3.10, 2.38 and 2.92 log10 CFU/g, respectively, were observed following a 15-h exponential chill rate. Similar inhibitory effects were observed for 18 and 21 chill rates with the antimicrobials at 1% concentrations. While sodium lactate and sodium acetate concentrations of 1% were sufficient to control C. perfringens germination and outgrowth (<1.0 log10 CFU/g growth) following 15 h chill rates, higher concentrations were required for 18 and 21 h chill rates. Ional at 1% concentration was effective in inhibiting germination and outgrowth to <1.0 log10 CFU/g of C. perfringens for all three chill rates (15, 18 and 21 h) tested. Use of sodium salts of organic acids in formulation of ready-to-eat meat products can reduce the risk of C. perfringens spore germination and outgrowth during chilling. PMID:15135954

Juneja, V K; Thippareddi, H

2004-06-01

165

Distribution of Clostridium perfringens and Fecal Sterols in a Benthic Coastal Marine Environment Influenced by the Sewage Outfall from McMurdo Station, Antarctica†  

PubMed Central

The spatial distribution, movement, and impact of the untreated wastewater outfall from McMurdo Station, Antarctica, were investigated under early austral summer conditions. The benthic environment was examined to determine the distribution of Clostridium perfringens in sediment cores and the intestinal contents of native invertebrates and fish along a transect of stations. These stations extended ca. 411 m south of the outfall. The findings revealed that the concentration of C. perfringens decreased with depth in the sediment and distance from the outfall. High percentages of tunicates and sea urchins were colonized with this bacterium along the transect. Coprostanol concentrations were also measured in sediment samples taken from each of the transect stations, and a similar trend was observed. These results are in agreement with the findings of previous studies performed with the water column and collectively provide evidence that the disposal of domestic wastes deserves special consideration in polar marine environments. PMID:9647835

Edwards, Diane D.; McFeters, Gordon A.; Venkatesan, M. Indira

1998-01-01

166

Antagonism exerted by an association of a Bacteroides thetaiotaomicron strain and a Fusobacterium necrogenes strain against Clostridium perfringens in gnotobiotic mice and in fecal suspensions incubated in vitro.  

PubMed Central

Antagonism between an association of Bacteroides thetaiotaomicron and Fusobacterium necrogenes strains and two strains of Clostridium perfringens was evidenced both in vivo in gnotobiotic mice and ex vivo in fecal suspensions incubated for 22 h at 37 degrees C. Several features of this antagonism were similar in and ex vivo. (i) An obligate and continuous synergy between B. thetaiotaomicron and F. necrogenes was required; (ii) the two C. perfringens strains did not respond to the same extent to this antagonism; and (iii) expression of the antagonism was host and diet dependent. Neither diffusible nor soluble inhibitory substances were detectable in feces of gnotobiotic mice, nor could depletion of nutrients be identified as causing antagonism in both in and ex vivo experiments. Our findings support the hypothesis that a reversible bacteriostasis induced by the inhibitory strains acting together continuously, and hindering the target strain from utilizing available nutrients, was responsible for this antagonism. PMID:2537255

Yurdusev, N; Ladire, M; Ducluzeau, R; Raibaud, P

1989-01-01

167

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

168

Use of calcium, potassium, and sodium lactates to control germination and outgrowth of Clostridium perfringens spores during chilling of injected pork.  

PubMed

Inhibition of Clostridium perfringens spore germination and outgrowth during abusive chilling regimes was investigated by the incorporation of lactates of calcium (CaL), potassium (KL) and sodium (NaL) in injected pork. Lactates (Ca, K, or Na) were incorporated into injected pork samples at four different concentrations (1.0%, 2.0%, 3.0%, and 4.8%), along with a no-lactate control. A three-strain cocktail of C. perfringens spores was inoculated into the product (injected pork) to obtain a final spore population of ca. 2.0-2.5 log(10)CFU/g. Chilling of injected pork (control) from 54.4 to 7.2 degrees C within 6.5, 9, 12, 15, 18, and 21 h exponential chill rates resulted in C. perfringens population increases of 0.49, 2.40, 4.02, 5.03, 6.24, and 6.30 log(10)CFU/g, respectively. Addition of CaL at 1.0% or KL and NaL > or = 2.0% to injected pork was able to control C. perfringens germination and outgrowth to <1 logCFU/g, meeting the USDA-FSIS performance standard. However, extension of chilling rates beyond 9.0 h (up to 21 h) required addition of CaL ( > or = 2.0%), KL or NaL ( > or = 3.0%) to meet the stabilization performance standard. In general, CaL was more effective compared to KL or NaL for all the chilling regimes, in reducing the potential risk of C. perfringens germination and outgrowth. PMID:17613365

Reddy Velugoti, Padmanabha; Rajagopal, Lakshman; Juneja, Vijay; Thippareddi, Harshavardhan

2007-01-01

169

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

170

Use of organic acids for the control of Clostridium perfringens in cooked vacuum-packaged restructured roast beef during an alternative cooling procedure.  

PubMed

This study was conducted to determine how well Clostridium perfringens spores germinate and grow in restructured roast beef treated with different commercial organic salts during an alternative chilling procedure. The meat was prepared according to an industrial recipe (10% water, 1.5% sodium chloride, and 0.5% sodium triphosphate). The base meat was treated with sodium citrate at 2 or 4.8% (wt/wt), buffered to a pH of 5.6, 5.0, or 4.4 (six treatments); a 60% (wt/wt) solution of sodium lactate at 2 or 4.8% (wt/wt); sodium acetate at 0.25% (wt/wt); or sodium diacetate at 0.25% (wt/wt). Untreated meat was used as a control. Meat samples were inoculated with a three-strain cocktail of C. perfringens spores (strains ATCC 10388, NCTC 8238, and NCTC 8239). Meat was vacuum packaged in bags and cooked in a stirred water bath to an internal temperature of 75 degrees C for 20 min, and then the bags were cooled from 54.4 to 4.4 degrees C within 18 h. Samples were taken after inoculation, after cooking, and after chilling. Spore and vegetative cell counts were obtained after incubation at 37 degrees C for 8 to 10 h in Fung's Double Tubes containing tryptose sulfite agar without egg yolk enrichment. Cooking was not sufficient to eliminate C. perfringens spores. Over the 18-h cooling period, sodium citrate, sodium lactate, and sodium diacetate reduced the growth of C. perfringens to < 1 log unit, a growth level that meets U.S. Department of Agriculture performance standards. The use of sodium citrate or sodium lactate at a concentration of > or = 2% (wt/wt) inhibited C. perfringens growth over the 18-h cooling period. PMID:12929827

Sabah, J R; Thippareddi, H; Marsden, J L; Fung, D Y C

2003-08-01

171

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

172

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

173

Predictive model for Clostridium perfringens growth in roast beef during cooling and inhibition of spore germination and outgrowth by organic acid salts.  

PubMed

Spores of foodborne pathogens can survive traditional thermal processing schedules used in the manufacturing of processed meat products. Heat-activated spores can germinate and grow to hazardous levels when these products are improperly chilled. Germination and outgrowth of Clostridium perfringens spores in roast beef during chilling was studied following simulated cooling schedules normally used in the processed-meat industry. Inhibitory effects of organic acid salts on germination and outgrowth of C. perfringens spores during chilling and the survival of vegetative cells and spores under abusive refrigerated storage was also evaluated. Beef top rounds were formulated to contain a marinade (finished product concentrations: 1% salt, 0.2% potassium tetrapyrophosphate, and 0.2% starch) and then ground and mixed with antimicrobials (sodium lactate and sodium lactate plus 2.5% sodium diacetate and buffered sodium citrate and buffered sodium citrate plus 1.3% sodium diacetate). The ground product was inoculated with a three-strain cocktail of C. perfringens spores (NCTC 8238, NCTC 8239, and ATCC 10388), mixed, vacuum packaged, heat shocked for 20 min at 75 degrees C, and chilled exponentially from 54.5 to 7.2 degrees C in 9, 12, 15, 18, or 21 h. C. perfringens populations (total and spore) were enumerated after heat shock, during chilling, and during storage for up to 60 days at 10 degrees C using tryptose-sulfite-cycloserine agar. C. perfringens spores were able to germinate and grow in roast beef (control, without any antimicrobials) from an initial population of ca. 3.1 log CFU/g by 2.00, 3.44, 4.04, 4.86, and 5.72 log CFU/g after 9, 12, 15, 18, and 21 h of exponential chilling. A predictive model was developed to describe sigmoidal C. perfringens growth curves during cooling of roast beef from 54.5 to 7.2 degrees C within 9, 12, 15, 18, and 21 h. Addition of antimicrobials prevented germination and outgrowth of C. perfringens regardless of the chill times. C. perfringens spores could be recovered from samples containing organic acid salts that were stored up to 60 days at 10 degrees C. Extension of chilling time to > or =9 h resulted in >1 log CFU/g growth of C. perfringens under anaerobic conditions in roast beef. Organic acid salts inhibited outgrowth of C. perfringens spores during chilling of roast beef when extended chill rates were followed. Although C. perfringens spore germination is inhibited by the antimicrobials, this inhibition may represent a hazard when such products are incorporated into new products, such as soups and chili, that do not contain these antimicrobials, thus allowing spore germination and outgrowth under conditions of temperature abuse. PMID:16355831

Sánchez-Plata, Marcos X; Amézquita, Alejandro; Blankenship, Erin; Burson, Dennis E; Juneja, Vijay; Thippareddi, Harshavardhan

2005-12-01

174

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

175

In vivo antimicrobial potentials of garlic against Clostridium perfringens and its promotant effects on performance of broiler chickens.  

PubMed

This study was conducted to investigate in vivo antimicrobial potential of garlic against Clostridium perferinges and resultant promotant effects on performance of the broiler chickens. Garlic powder was used as an alternative to GPAs (Growth Promotant Antibiotics) to prevent subclinical Necrotic Enteritis (NE) due to C. perferinges. 120 day-old broiler chicks were randomly distributed to six treatment groups of 20 chicks each (2 replicates(-10) chicks). Six isonutrient diets supplemented with garlic at graded levels of 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 g kg(-1) were fed to the birds for seven weeks. Data were collected weekly on performance parameters including feed intake, weight gain and feed conversion ratio (FCR). Also, on the 21 35 and 49th days of the study, two birds per group were randomly selected, slaughtered and dissected. 1 g of caecal contents per each bird were sampled into labelled sterile sample bottles. The samples were subjected to culturing, bacterial identification and colony counting. All data were subjected to analysis of variance. Results showed that garlic significantly (p > 0.05) depressed feed intake (3310 g feed/bird at 1.0 g kg(-1) supplementation) but improved FCR. The supplement has no significant effect on weight gain but C. perfringens colony counts in the treated groups, were numerically reduced (lowest count, 0.93 x 10(5) cfu g(-1) at 1.0 g kg(-1) supplementation), as compared to the control. It is therefore concluded that diets could be supplemented with garlic at dose range of 1.0 to 1.5 g kg(-1) to prevent subclinical NE and achieve improved performance in birds. PMID:24517015

Jimoh, A A; Ibitoye, E B; Dabai, Y U; Garba, S

2013-12-15

176

The effect of calcium and sodium lactates on growth from spores of Bacillus cereus and Clostridium perfringens in a 'sous-vide' beef goulash under temperature abuse.  

PubMed

The effect of calcium and sodium lactates on growth from spores of Bacillus cereus and Clostridium perfringens at three different concentrations (0, 1.5 and 3% w/w) and at different temperatures (10, 15 and 20 degrees C for B. cereus and 15, 20 and 25 degrees C for C. perfringens) was investigated, using beef goulash as a model system for pasteurised vacuum-packaged convenience foods. Calcium lactate at a level of 3% reduced the pH values of the samples from 6.0 to 5.5. No B. cereus growth was observed at 10 degrees C, but after 7 days at an incubation temperature of 15 degrees C, cell number increased by 1 log cfu/g in the control samples. At this temperature, lactates were seen to be effective at inhibiting growth. Calcium lactate was more inhibitory than sodium lactate as the growth of B. cereus was inhibited at 1.5 and 3% concentrations at 20 degrees C, respectively. Growth of C. perfringens was arrested in the presence of 1.5% calcium lactate at all storage temperatures, whereas growth was inhibited by 3% sodium lactate only at 15 degrees C. PMID:11205943

Aran, N

2001-01-22

177

Differential outgrowth potential of Clostridium perfringens food-borne isolates with various cpe-genotypes in vacuum-packed ground beef during storage at 12°C.  

PubMed

In the current study, the outgrowth of spores of 15 different food isolates of Clostridium perfringens was evaluated in vacuum-packed ground beef during storage at 12°C and 25°C. This included enterotoxic strains carrying the gene encoding the CPE enterotoxin on the chromosome (C-cpe), on a plasmid (P-cpe) and cpe-negative strains. The 15 strains were selected from a larger group of strains that were first evaluated for their ability to sporulate in modified Duncan-Strong sporulating medium. Sporulation ability varied greatly between strains but was not associated with a particular cpe genotype. In line with previous studies, the tested C-cpe strains produced spores with significantly higher heat resistance than the cpe-negative and P-cpe strains (both IS1151 and IS1470-like) with the exception of strain VWA009. Following inoculation of vacuum-packed cooked ground beef with spores, the heat-resistant C-cpe strains showed lower outgrowth potential in this model food stored at 12°C than the P-cpe and cpe-negative strains, while no significant differences were observed at 25°C. These results suggest that the latter strains may have a competitive advantage over C-cpe strains at reduced temperatures during storage of foods that support the growth of C. perfringens. While spores of P-cpe strains are readily inactivated by heat processing, post-processing contamination by food handlers who may carry P-cpe strains that have a better growth potential at lower temperatures must be avoided. The varying responses of C. perfringens spores to heat and the differences in outgrowth capacity at different temperatures are factors to be considered in strain selection for challenge tests, and for predictive modelling of C. perfringens. PMID:25461607

Xiao, Yinghua; Wagendorp, Arjen; Abee, Tjakko; Wells-Bennik, Marjon H J

2015-02-01

178

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

179

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

180

Relative disease susceptibility and clostridial toxin antibody responses in three commercial broiler lines coinfected with Clostridium perfringens and Eimeria maxima using an experimental model of necrotic enteritis.  

PubMed

Necrotic enteritis is an enteric disease of poultry resulting from infection by Clostridium perfringens with coinfection by Eimeria spp. constituting a major risk factor for disease pathogenesis. This study compared three commercial broiler chicken lines using an experimental model of necrotic enteritis. Day-old male Cobb, Ross, and Hubbard broilers were orally infected with viable C. perfringens and E. maxima and fed a high-protein diet to promote the development of experimental disease. Body weight loss, intestinal lesions, and serum antibody levels against alpha-toxin and necrotic enteritis B-like (NetB) toxin were measured as parameters of disease susceptibility and host immune response. Cobb chickens exhibited increased body weight loss compared with Ross and Hubbard breeds and greater gut lesion severity compared with Ross chickens. NetB antibody levels were greater in Cobb chickens compared with the Ross or Hubbard groups. These results suggest that Cobb chickens may be more susceptible to necrotic enteritis in the field compared with the Ross and Hubbard lines. PMID:24283139

Jang, Seung I; Lillehoj, Hyun S; Lee, Sung-Hyen; Lee, Kyung Woo; Lillehoj, Erik P; Hong, Yeong Ho; An, Dong-Jun; Jeoung, D Hye-Young; Chun, Ji-Eun

2013-09-01

181

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

182

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

183

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

PubMed Central

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

2014-01-01

184

Structural and Functional Characterization of the Clostridium perfringens N-Acetylmannosamine-6-phosphate 2-Epimerase Essential for the Sialic Acid Salvage Pathway.  

PubMed

Pathogenic bacteria are endowed with an arsenal of specialized enzymes to convert nutrient compounds from their cell hosts. The essential N-acetylmannosamine-6-phosphate 2-epimerase (NanE) belongs to a convergent glycolytic pathway for utilization of the three amino sugars, GlcNAc, ManNAc, and sialic acid. The crystal structure of ligand-free NanE from Clostridium perfringens reveals a modified triose-phosphate isomerase (?/?)8 barrel in which a stable dimer is formed by exchanging the C-terminal helix. By retaining catalytic activity in the crystalline state, the structure of the enzyme bound to the GlcNAc-6P product identifies the topology of the active site pocket and points to invariant residues Lys(66) as a putative single catalyst, supported by the structure of the catalytically inactive K66A mutant in complex with substrate ManNAc-6P. (1)H NMR-based time course assays of native NanE and mutated variants demonstrate the essential role of Lys(66) for the epimerization reaction with participation of neighboring Arg(43), Asp(126), and Glu(180) residues. These findings unveil a one-base catalytic mechanism of C2 deprotonation/reprotonation via an enolate intermediate and provide the structural basis for the development of new antimicrobial agents against this family of bacterial 2-epimerases. PMID:25320079

Pélissier, Marie-Cécile; Sebban-Kreuzer, Corinne; Guerlesquin, Françoise; Brannigan, James A; Bourne, Yves; Vincent, Florence

2014-12-19

185

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

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, alphamethyl-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

186

Molecular Characteristics of Clostridium perfringens TpeL Toxin and Consequences of Mono-O-GlcNAcylation of Ras in Living Cells*  

PubMed Central

TpeL is a member of the family of clostridial glucosylating toxins produced by Clostridium perfringens type A, B, and C strains. In contrast to other members of this toxin family, it lacks a C-terminal polypeptide repeat domain, which is suggested to be involved in target cell binding. It was shown that the glucosyltransferase domain of TpeL modifies Ras in vitro by mono-O-glucosylation or mono-O-GlcNAcylation (Nagahama, M., Ohkubo, A., Oda, M., Kobayashi, K., Amimoto, K., Miyamoto, K., and Sakurai, J. (2011) Infect. Immun. 79, 905–910). Here we show that TpeL preferably utilizes UDP-N-acetylglucosamine (UDP-GlcNAc) as a sugar donor. Change of alanine 383 of TpeL to isoleucine turns the sugar donor preference from UDP-GlcNAc to UDP-glucose. In contrast to previous studies, we show that Rac is a poor substrate in vitro and in vivo and requires 1–2 magnitudes higher toxin concentrations for modification by TpeL. The toxin is autoproteolytically processed in the presence of inositol hexakisphosphate (InsP6) by an intrinsic cysteine protease domain, located next to the glucosyltransferase domain. A C-terminally extended TpeL full-length variant (TpeL1–1779) induces apoptosis in HeLa cells (most likely by mono-O-GlcNAcylation of Ras), and inhibits Ras signaling including Ras-Raf interaction and ERK activation. In addition, TpeL blocks Ras signaling in rat pheochromocytoma PC12 cells. TpeL is a glucosylating toxin, which modifies Ras and induces apoptosis in target cells without having a typical C-terminal polypeptide repeat domain. PMID:22665487

Guttenberg, Gregor; Hornei, Sven; Jank, Thomas; Schwan, Carsten; Lü, Wei; Einsle, Oliver; Papatheodorou, Panagiotis; Aktories, Klaus

2012-01-01

187

Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer  

PubMed Central

Background Translational exploration of bacterial toxins has come to the forefront of research given their potential as a chemotherapeutic tool. Studies in select tissues have demonstrated that Clostridium perfringens iota toxin binds to CD44 and lipolysis stimulated lipoprotein receptor (LSR) cell-surface proteins. We recently demonstrated that LSR expression correlates with estrogen receptor positive breast cancers and that LSR signaling directs aggressive, tumor-initiating cell behaviors. Herein, we identify the mechanisms of iota toxin cytotoxicity in a tissue-specific, breast cancer model with the ultimate goal of laying the foundation for using iota toxin as a targeted breast cancer therapy. Methods In vitro model systems were used to determine the cytotoxic effect of iota toxin on breast cancer intrinsic subtypes. The use of overexpression and knockdown technologies confirmed the roles of LSR and CD44 in regulating iota toxin endocytosis and induction of cell death. Lastly, cytotoxicity assays were used to demonstrate the effect of iota toxin on a validated set of tamoxifen resistant breast cancer cell lines. Results Treatment of 14 breast cancer cell lines revealed that LSR+/CD44- lines were highly sensitive, LSR+/CD44+ lines were slightly sensitive, and LSR-/CD44+ lines were resistant to iota cytotoxicity. Reduction in LSR expression resulted in a significant decrease in toxin sensitivity; however, overexpression of CD44 conveyed toxin resistance. CD44 overexpression was correlated with decreased toxin-stimulated lysosome formation and decreased cytosolic levels of iota toxin. These findings indicated that expression of CD44 drives iota toxin resistance through inhibition of endocytosis in breast cancer cells, a role not previously defined for CD44. Moreover, tamoxifen-resistant breast cancer cells exhibited robust expression of LSR and were highly sensitive to iota-induced cytotoxicity. Conclusions Collectively, these data are the first to show that iota toxin has the potential to be an effective, targeted therapy for breast cancer. PMID:24990559

2014-01-01

188

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

PubMed Central

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 to dietary antibiotics are therefore urgently required. To develop the substitutes, it is important to understand host immune responses to Cp infection. However, the knowledge is still lacking. We therefore investigated gene expression profiles within immunologically-relevant tissue, the spleen, in order to identify factors that are involved in immunity to NE and have potential as therapeutic targets. Results Use of a 44 K Agilent chicken genome microarray revealed significant up-regulation of many immune-associated genes in Cp-challenged chickens, including galectin 3, IFNAR1, IgY-receptor, TCR?, granzyme A, and mannose-6-P-R, which were subsequently validated by quantitative PCR assays. Functional annotation of differentially expressed genes was conducted using the High Throughput Gene Ontology Functional Annotation database. Medicated and Non-medicated chickens had similar annotation profiles with cell activities and regulation being the most dominant biological processes following Cp infection. Conclusion Broiler chickens demonstrated an intricate and holistic magnitude of host response to Cp challenge and the development of NE. Although the influence of dietary antibiotics appeared to be less significant than the disease process, both had a considerable impact on the host response. Markers previously identified in intestinal inflammatory diseases of other species, including humans, and indicators of enhanced antibody responses, appeared to be involved in the chicken response to Cp challenge. The significance in host immune responses of immune mediators identified from the present study warrants further studies to verify their functions during NE development and to determine their potential application to control NE disease. PMID:19500416

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

2009-01-01

189

Effect of epsilon toxin-GFP on MDCK cells and renal tubules in vivo.  

PubMed

Epsilon toxin (epsilon-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxemia, also known as pulpy kidney disease, in livestock. Recombinant epsilon-toxin-green fluorescence protein (epsilon-toxin-GFP) and epsilon-prototoxin-GFP were successfully expressed in Escherichia coli. MTT assays on MDCK cells confirmed that recombinant epsilon-toxin-GFP retained the cytotoxicity of the native toxin. Direct fluorescence analysis of MDCK cells revealed a homogeneous peripheral pattern that was temperature sensitive and susceptible to detergent. epsilon-Toxin-GFP and epsilon-prototoxin-GFP bound to endothelia in various organs of injected mice, especially the brain. However, fluorescence mainly accumulated in kidneys. Mice injected with epsilon-toxin-GFP showed severe kidney alterations, including hemorrhagic medullae and selective degeneration of distal tubules. Moreover, experiments on kidney cryoslices demonstrated specific binding to distal tubule cells of a range of species. We demonstrate with new recombinant fluorescence tools that epsilon-toxin binds in vivo to endothelial cells and renal tubules, where it has a strong cytotoxic effect. Our binding experiments indicate that an epsilon-toxin receptor is expressed on renal distal tubules of mammalian species, including human. PMID:15208360

Soler-Jover, Alex; Blasi, Juan; Gómez de Aranda, Inma; Navarro, Piedad; Gibert, Maryse; Popoff, Michel R; Martín-Satué, Mireia

2004-07-01

190

Mechanism of Clostridium perfringens Enterotoxin Interaction with Claudin-3/-4 Protein Suggests Structural Modifications of the Toxin to Target Specific Claudins*  

PubMed Central

Claudins (Cld) are essential constituents of tight junctions. Domain I of Clostridium perfringens enterotoxin (cCPE) binds to the second extracellular loop (ECL2) of a subset of claudins, e.g. Cld3/4 and influences tight junction formation. We aimed to identify interacting interfaces and to alter claudin specificity of cCPE. Mutagenesis, binding assays, and molecular modeling were performed. Mutation-guided ECL2 docking of Cld3/4 onto the crystal structure of cCPE revealed a common orientation of the proposed ECL2 helix-turn-helix motif in the binding cavity of cCPE: residues Leu150/Leu151 of Cld3/4 bind similarly to a hydrophobic pit formed by Tyr306, Tyr310, and Tyr312 of cCPE, and Pro152/Ala153 of Cld3/4 is proposed to bind to a second pit close to Leu223, Leu254, and Leu315. However, sequence variation in ECL2 of these claudins is likely responsible for slightly different conformation in the turn region, which is in line with different cCPE interaction modes of Cld3 and Cld4. Substitutions of other so far not characterized cCPE residues lining the pocket revealed two spatially separated groups of residues (Leu223, Asp225, and Arg227 and Leu254, lle258, and Asp284), which are involved in binding to Cld3 and Cld4, albeit differently. Involvement of Asn148 of Cld3 in cCPE binding was confirmed, whereas no evidence for involvement of Lys156 or Arg157 was found. We show structure-based alteration of cCPE generating claudin binders, which interact subtype-specific preferentially either with Cld3 or with Cld4. The obtained mutants and mechanistic insights will advance the design of cCPE-based modulators to target specific claudin subtypes related either to paracellular barriers that impede drug delivery or to tumors. PMID:22128179

Veshnyakova, Anna; Piontek, Jörg; Protze, Jonas; Waziri, Negar; Heise, Ivonne; Krause, Gerd

2012-01-01

191

EFFECT OF SPICES AND ORGANIC ACIDS ON THE GROWTH OF CLOSTRIDIUM PERFRINGENS FROM SPORE INOCULA DURING COOLING OF SOUS-VIDE COOKED GROUND BEEF PRODUCTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Heat treatments given to minimally processed food products are not sufficient to kill C. perfringens spores when present. Thus, the heat resistant spores may survive, germinate, outgrow and multiply into high numbers of vegetative cells if the rate and extent of cooling is inadequate. There is a ...

192

Characterization of the plasmidic or chromosomal cpe gene and metabolic activities in Clostridium perfringens isolates from food in San Luis--Argentina.  

PubMed

Food poisoning and non-food poisoning illnesses due to C. perfringens (by enterotoxin production) have been associated to chromosomal or plasmidic location of the cpe gene, respectively. Clostridial pathogenicity has been correlated to protease and azoreductase production. The aim of this work was: i) to assess the sanitary-hygienic quality of dehydrated soups (100 samples) consumed in San Luis - Argentina; ii) to verify the presence of C. perfringens in these food products using the "Most Probable Number" method (MPN) and plate-counting methods; iii) to characterise enterotoxigenicity in strain isolates by RPLA; iv) to determine the chromosomal or plasmidic location of the cpe gene in enterotoxigenic strains previously isolated from food in our lab, using PCR; v) to correlate chromosomal cpe and spore heat-resistance; vi) to compare protease activity in cpe+ and cpe- strains; and vii) to compare azoreductase activity in cpe+ and cpe- strains. Twenty-six isolates had a count a 3-43 bacteria g(-1) count using MPN; 7.7% exceeded the Argentine Food Code (CAA) limit. All isolates showed protease activity: enterotoxigenic isolates had higher protease activity than non-enterotoxigenic isolates. All isolates showed azoreductase activity: enterotoxigenic isolates had higher activity and shorter reducing times. Enterotoxigenic isolates showed chromosomal location for the gene responsible for the enterotoxin. PMID:21526657

Corigliano, Mariana Georgina; de Guzmán, Ana María Stefanini; Stagnitta, Patricia Virginia

2011-03-01

193

Glycoside Hydrolase Family 89 ?-N-acetylglucosaminidase from Clostridium perfringens Specifically Acts on GlcNAc?1,4Gal?1R at the Non-reducing Terminus of O-Glycans in Gastric Mucin*  

PubMed Central

In mammals, ?-linked GlcNAc is primarily found in heparan sulfate/heparin and gastric gland mucous cell type mucin. ?-N-Acetylglucosaminidases (?GNases) belonging to glycoside hydrolase family 89 are widely distributed from bacteria to higher eukaryotes. Human lysosomal ?GNase is well known to degrade heparin and heparan sulfate. Here, we reveal the substrate specificity of ?GNase (AgnC) from Clostridium perfringens strain 13, a bacterial homolog of human ?GNase, by chemically synthesizing a series of disaccharide substrates containing ?-linked GlcNAc. AgnC was found to release GlcNAc from GlcNAc?1,4Gal?1pMP and GlcNAc?1pNP substrates (where pMP and pNP represent p-methoxyphenyl and p-nitrophenyl, respectively). AgnC also released GlcNAc from porcine gastric mucin and cell surface mucin. Because AgnC showed no activity against any of the GlcNAc?1,2Gal?1pMP, GlcNAc?1,3Gal?1pMP, GlcNAc?1,6Gal?1pMP, and GlcNAc?1,4GlcA?1pMP substrates, this enzyme may represent a specific glycosidase required for degrading ?-GlcNAc-capped O-glycans of the class III mucin secreted from the stomach and duodenum. Deletion of the C-terminal region containing several carbohydrate-binding module 32 (CBM32) domains significantly reduced the activity for porcine gastric mucin; however, activity against GlcNAc?1,4Gal?1pMP was markedly enhanced. Dot blot and ELISA analyses revealed that the deletion construct containing the C-terminal CBM-C2 to CBM-C6 domains binds strongly to porcine gastric mucin. Consequently, tandem CBM32 domains located near the C terminus of AgnC should function by increasing the affinity for branched or clustered ?-GlcNAc-containing glycans. The agnC gene-disrupted strain showed significantly reduced growth on the class III mucin-containing medium compared with the wild type strain, suggesting that AgnC might have an important role in dominant growth in intestines. PMID:21177247

Fujita, Masaya; Tsuchida, Akiko; Hirata, Akiko; Kobayashi, Natsumi; Goto, Kohtaro; Osumi, Kenji; Hirose, Yuriko; Nakayama, Jun; Yamanoi, Takashi; Ashida, Hisashi; Mizuno, Mamoru

2011-01-01

194

Isolation of Nitrofurantoin-Resistant Mutants of Nitroreductase Producing Clostridium sp. Strains from the Human Intestinal Tract  

Microsoft Academic Search

Five spontaneous nitrofurantoin-resistant mutants (one each of Clostridium leptum, Clostridium paraputrifi- cum, two other Clostridium spp. strains from the human intestinal microflora, and Clostridium perfringens ATCC 3626) were selected by growth on a nitrofurantoin-containing medium. All of the Clostridium wild-type and mutant strains produced nitroreductase, as was shown by the conversion of 4-nitrobenzoic acid to 4-aminobenzoic acid. High-performance liquid chromatography

FATEMEH RAFII

1998-01-01

195

42 CFR 73.3 - HHS select agents and toxins.  

Code of Federal Regulations, 2010 CFR

...toxins: Abrin Botulinum neurotoxins Botulinum neurotoxin producing species of Clostridium Cercopithecine herpesvirus 1 (Herpes B virus) Clostridium perfringens epsilon toxin Coccidioides posadasii/Coccidioides immitis Conotoxins...

2010-10-01

196

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

197

In vitro inhibition of growth of Escherichia coli, Salmonella Typhimurium, and Clostridia perfringens using Probiotics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Salmonella Typhimurium, Escherichia coli and Clostridium perfringens are pathogenic organisms found in horses [1] and they cause disease in animals or humans [2]. Due to concern over pathogens such as these, there is increasing interest in antimicrobial alternatives to prevent or reduce the prevalen...

198

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

199

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

200

Identification of the Cellular Receptor of Clostridium spiroforme Toxin  

PubMed Central

Clostridium spiroforme produces the binary actin-ADP-ribosylating toxin CST (C. spiroforme toxin), which has been proposed to be responsible for diarrhea, enterocolitis, and eventually death, especially in rabbits. Here we report on the recombinant production of the enzyme component (CSTa) and the binding component (CSTb) of C. spiroforme toxin in Bacillus megaterium. By using the recombinant toxin components, we show that CST enters target cells via the lipolysis-stimulated lipoprotein receptor (LSR), which has been recently identified as the host cell receptor of the binary toxins Clostridium difficile transferase (CDT) and Clostridium perfringens iota toxin. Microscopic studies revealed that CST, but not the related Clostridium botulinum C2 toxin, colocalized with LSR during toxin uptake and traffic to endosomal compartments. Our findings indicate that CST shares LSR with C. difficile CDT and C. perfringens iota toxin as a host cell surface receptor. PMID:22252869

Papatheodorou, Panagiotis; Wilczek, Claudia; Nölke, Thilo; Guttenberg, Gregor; Hornuss, Daniel; Schwan, Carsten

2012-01-01

201

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

202

Monitoring of anti-C. perfringens bacteriophage CpV1 persistence in gastrointestinal tracts of broilers.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A factor limiting promotion of poultry products to the world market is any contamination of birds with pathogens, including Clostridium perfringens. The latter is often accountable for significant economical losses in production of commercial birds because of a possibility of the development of necr...

203

epsilon. prime /. epsilon. : Review and recent progress  

SciTech Connect

The evolution of the theoretical perspective on {epsilon}{prime}/{epsilon} is reviewed. The introduction of the Z{sup O} penguin and the effects of high M{sub t} are discussed, in particular the possibility for {epsilon}{prime}/{epsilon} to be identically zero. Recent calculations of {epsilon}{prime}/{epsilon} based on current estimates and bounds on the input parameters are presented. 41 refs., 13 figs.

Franzini, P.J.

1991-04-19

204

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

205

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

206

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

207

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.  

Code of Federal Regulations, 2010 CFR

...Antitoxin and 10 L0 doses of Standard Toxin die, the results of the test are inconclusive...Antitoxin and 10 L+ doses of Standard Toxin die, the results of the test are inconclusive...34 and 10 L0 doses of Standard Toxin die, the antitoxin is considered to...

2010-01-01

208

9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.  

Code of Federal Regulations, 2010 CFR

...Antitoxin and 10 L0 doses of Standard Toxin die, the results of the test are inconclusive...Antitoxin and 10 L+ doses of Standard Toxin die, the results of the test are inconclusive...50 and 10 L0 doses of Standard Toxin die, the antitoxin is considered to...

2010-01-01

209

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.  

Code of Federal Regulations, 2011 CFR

...not cause sickness or death in injected mice. (iii) L + dose. The smallest...death in at least 80 percent of injected mice. (iv) Standard antitoxin. The...and hold in ice water until injections of mice can be made. (vi) Five Swiss...

2011-01-01

210

9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.  

Code of Federal Regulations, 2011 CFR

...not cause sickness or death in injected mice. (iii) L + dose. The smallest...death in at least 80 percent of injected mice. (iv) Standard antitoxin. The...and hold in ice water until injections of mice can be made. (vi) Five Swiss...

2011-01-01

211

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.  

Code of Federal Regulations, 2014 CFR

...test sample with 33 ml of diluent and combine 1 ml of this dilution with 1 ml of the...diluted to contain 10 L0 doses. (iv) Combine 1 International Unit of Standard Antitoxin with 10 L0 doses of Standard Toxin and combine 1 International Unit of Standard...

2014-01-01

212

9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.  

Code of Federal Regulations, 2013 CFR

...test sample with 49 ml of diluent and combine 1 ml of this dilution with 1 ml of the...diluted to contain 10 L0 doses. (iv) Combine 10 International Units of Standard Antitoxin... doses of diluted Standard Toxin and combine 10 International Units of Standard...

2013-01-01

213

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.  

Code of Federal Regulations, 2013 CFR

...test sample with 33 ml of diluent and combine 1 ml of this dilution with 1 ml of the...diluted to contain 10 L0 doses. (iv) Combine 1 International Unit of Standard Antitoxin with 10 L0 doses of Standard Toxin and combine 1 International Unit of Standard...

2013-01-01

214

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.  

Code of Federal Regulations, 2012 CFR

...test sample with 33 ml of diluent and combine 1 ml of this dilution with 1 ml of the...diluted to contain 10 L0 doses. (iv) Combine 1 International Unit of Standard Antitoxin with 10 L0 doses of Standard Toxin and combine 1 International Unit of Standard...

2012-01-01

215

9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.  

Code of Federal Regulations, 2012 CFR

...test sample with 49 ml of diluent and combine 1 ml of this dilution with 1 ml of the...diluted to contain 10 L0 doses. (iv) Combine 10 International Units of Standard Antitoxin... doses of diluted Standard Toxin and combine 10 International Units of Standard...

2012-01-01

216

Clostridium bacteremia: emphasis on the poor prognosis in cirrhotic patients.  

PubMed

Bacteremic episodes caused by anaerobes are unusual and the clinical importance of Clostridium bacteremia remains unclear. This retrospective case study examined the risk factors among a group of patients who developed Clostridium bacteremia. Medical records from 73 episodes of clostridial bacteremia in 73 patients treated in a medical center during an 11-year period were reviewed. Of all episodes, 96% were community-acquired. Twelve percent of patients had polymicrobial bacteremia, with Escherichia coli being the most common accompanying bacterium. Diabetes mellitus (26%) and liver cirrhosis (25%) were the most common underlying diseases. The most common etiological organisms were Clostridium perfringens (77%), Clostridium bifermentans (9%), and Clostridium septicum (4%). Only one patient with C. septicum bacteremia had a histocytotoxic infection, which was a fatal gas gangrene. Univariate analysis of data from patients with monomicrobial Clostridium bacteremia revealed that younger age (age < 65 years), underlying liver cirrhosis, and presence of septic shock at initial presentation were associated with fatality; but only the latter two variables were independently associated with fatality in multivariate logistic regression analysis. Appropriate antimicrobial therapy for monomicrobial Clostridium bacteremia did not significantly affect clinical outcomes, which might suggest that Clostridium species in the bloodstream can be regarded as merely contaminants or transient bacteremia. This suggestion was not supported by the finding that seven of 13 cirrhotic patients with monomicrobial Clostridium bacteremia died of sepsis, of whom six had not receive appropriate antimicrobial therapy. Therefore, the clinical importance of Clostridium bacteremia should be interpreted with caution because of its high risk of mortality in susceptible hosts, particularly cirrhotic patients, who do not receive appropriate therapy timely. PMID:11456356

Chen, Y M; Lee, H C; Chang, C M; Chuang, Y C; Ko, W C

2001-06-01

217

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

218

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

219

Clostridium welchii  

PubMed Central

The soluble antigens produced by twenty strains of Clostridium welchii Types B, C and D were investigated. The methods used were, in particular, the Ouchterlony double diffusion method in agar gels, besides the classical tests for lethal, haemolytic and enzymic factors, adapted where possible to give quantitative results. Some concentration of the culture filtrates was found necessary to demonstrate the antigens by gel diffusion, and this was effected satisfactorily only by freeze-drying. Precipitin bands, due to ?-, ?- and ?-toxins and their corresponding antibodies, were identified using these concentrated filtrates. Additional precipitin bands were due to antigens that have not yet been identified. All the toxins investigated appeared during the active growth phase; some, e.g. ?- and ?-toxins, were found to decline rapidly with longer incubation. This decline, together with the conversion of the ?-precursor to active toxin, could be attributed to the action of the enzymes which were also present in the filtrates, and the same effect could be produced by treatment with trypsin. The antigens of the Type D strains conformed to the expected pattern. Those of the Type B and C strains, however, exhibited wide variation in distribution and quantity, and were occasionally found in combinations that fitted neither of the accepted Types. ImagesFIG. 1FIG. 6FIGS. 9-10FIGS. 11-14FIG. 19FIG. 20FIG. 22FIG. 23FIG. 25 PMID:13574830

Orlans, E. S.; Jones, V. E.

1958-01-01

220

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

221

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

222

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

223

Lipolysis-stimulated lipoprotein receptor (LSR) is the host receptor for the binary toxin Clostridium difficile transferase (CDT)  

PubMed Central

Clostridium difficile infection (CDI) causes antibiotic-associated diarrhea and pseudomembranous colitis. Hypervirulent strains of the pathogen, which are responsible for increased morbidity and mortality of CDI, produce the binary actin-ADP ribosylating toxin Clostridium difficile transferase (CDT) in addition to the Rho-glucosylating toxins A and B. CDT depolymerizes the actin cytoskeleton, increases adherence and colonization of Clostridia by induction of microtubule-based cell protrusions and, eventually, causes death of target cells. Using a haploid genetic screen, we identified the lipolysis-stimulated lipoprotein receptor as the membrane receptor for CDT uptake by target cells. Moreover, we show that Clostridium perfringens iota toxin, which is a related binary actin-ADP ribosylating toxin, enters target cells via the lipolysis-stimulated lipoprotein receptor. Identification of the toxin receptors is essential for understanding of the toxin uptake and provides a most valuable basis for antitoxin strategies. PMID:21930894

Papatheodorou, Panagiotis; Carette, Jan E.; Bell, George W.; Schwan, Carsten; Guttenberg, Gregor; Brummelkamp, Thijn R.; Aktories, Klaus

2011-01-01

224

Clostridium difficile infection in horses: a review.  

PubMed

Clostridium difficile is considered one of the most important causes of diarrhea and enterocolitis in horses. Foals and adult horses are equally susceptible to the infection. The highly resistant spore of C. difficile is the infectious unit of transmission, which occurs primarily via the fecal-oral route, with sources of infection including equine feces, contaminated soil, animal hospitals, and feces of other animals. Two major risk factors for the development of C. difficile associated disease (CDAD) in adult horses are hospitalization and antimicrobial treatment, although sporadically, cases of CDAD can occur in horses that have not received antimicrobials or been hospitalized. The most common antibiotics associated with CDAD in horses are erythromycin, trimethoprim/sulfonamides, ?-lactam antimicrobials, clindamycin, rifampicin, and gentamicin. Clinical signs and intestinal lesions of CDAD infection are not specific and they cannot be used to distinguish infections by C. difficile from infections by other agents, such as Clostridium perfringens or Salmonella sp. The distribution of lesions throughout the intestinal tract seems to be age-dependent. Small intestine is invariably affected, and colon and cecum may or may not have lesions in foals<1-month old. Naturally acquired disease in older foals and adult horses has a more aboral distribution, affecting colon and sometimes cecum, but rarely the small intestine. Detection of toxin A, toxin B or both in intestinal contents or feces is considered the most reliable diagnostic criterion for CDAD in horses. Isolation of toxigenic strains of C. difficile from horses with intestinal disease is highly suggestive of CDAD. A better understanding of pathogenesis, reservoirs of infection, and vaccines and other methods of control is needed. Also further studies are recommended to investigate other possible predisposing factors and/or etiological agents of enteric diseases of horses. PMID:23642413

Diab, S S; Songer, G; Uzal, F A

2013-11-29

225

Isolation of nitrofurantoin-resistant mutants of nitroreductase-producing Clostridium sp. strains from the human intestinal tract.  

PubMed

Five spontaneous nitrofurantoin-resistant mutants (one each of Clostridium leptum, Clostridium paraputrificum, two other Clostridium spp. strains from the human intestinal microflora, and Clostridium perfringens ATCC 3626) were selected by growth on a nitrofurantoin-containing medium. All of the Clostridium wild-type and mutant strains produced nitroreductase, as was shown by the conversion of 4-nitrobenzoic acid to 4-aminobenzoic acid. High-performance liquid chromatography (HPLC) analysis of the mutants during incubation with 50 microg of nitrofurantoin per ml showed the gradual disappearance of the nitrofurantoin peak. The nitrofurantoin peak also disappeared when cell-free supernatants instead of cultures of each of the resistant and wild-type bacteria were used, but it persisted if the cell-free supernatants had been inactivated by heat. At least two of the mutants converted nitrofurantoin to metabolites without antibacterial activity, as was shown by a bioassay with a nitrofurantoin-susceptible Bacillus sp. strain. Nitrofurantoin at a high concentration (50 microg/ml) continued to exert some toxicity, even on the resistant strains, as was evident from the longer lag phases. This study indicates that Clostridium strains can develop resistance to nitrofurantoin while retaining the ability to produce nitroreductase; the mutants metabolized nitrofurantoin to compounds without antibacterial activity. PMID:9593138

Rafii, F; Hansen, E B

1998-05-01

226

Nosocomial Diarrhea: Evaluation and Treatment of Causes Other Than Clostridium difficile  

PubMed Central

Diarrhea is common among hospitalized patients but the causes are distinct from those of diarrhea in the community. We review existing data about the epidemiology of nosocomial diarrhea and summarize recent progress in understanding the mechanisms of diarrhea. Clinicians should recognize that most cases of nosocomial diarrhea have a noninfectious etiology, including medications, underlying illness, and enteral feeding. Apart from Clostridium difficile, the frequency of infectious causes such as norovirus and toxigenic strains of Clostridium perfringens, Klebsiella oxytoca, Staphylococcus aureus, and Bacteroides fragilis remains largely undefined and test availability is limited. Here we provide a practical approach to the evaluation and management of nosocomial diarrhea when tests for C. difficile are negative. PMID:22700831

Polage, Christopher R.; Solnick, Jay V.; Cohen, Stuart H.

2012-01-01

227

Collagenase Clostridium Histolyticum Injection  

MedlinePLUS

... Clostridium histolyticum injection is also used to treat Peyronie's disease (a thickening of tissue [plaque] inside the penis ... the finger(s) to be straightened. In people with Peyronie's disease, it works by helping to break down the ...

228

Diarylacylhydrazones: Clostridium-selective antibacterials with activity against stationary-phase cells.  

PubMed

Current antibiotics for treating Clostridium difficile infections (CDI), that is, metronidazole, vancomycin and more recently fidaxomicin, are mostly effective but treatment failure and disease relapse remain as significant clinical problems. The shortcomings of these agents are attributed to their low selectivity for C. difficile over normal gut microflora and their ineffectiveness against C. difficile spores. This Letter reports that certain diarylacylhydrazones identified during a high-throughput screening/counter-screening campaign show selective activity against two Clostridium species (C. difficile and Clostridium perfringens) over common gut commensals. Representative examples are shown to possess activity similar to vancomycin against clinical C. difficile strains and to kill stationary-phase C. difficile cells, which are responsible for spore production. Structure-activity relationships with additional synthesised analogues suggested a protonophoric mechanism may play a role in the observed activity/selectivity and this was supported by the well-known protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) showing selective anti-Clostridium effects and activity similar to diarylacylhydrazones against stationary-phase C. difficile cells. Two diarylacylhydrazones were shown to be non-toxic towards human FaDu and Hep G2 cells indicating that further studies with the class are warranted towards new drugs for CDI. PMID:24360560

Chen, Chao; Dolla, Naveen K; Casadei, Gabriele; Bremner, John B; Lewis, Kim; Kelso, Michael J

2014-01-15

229

Potential for growth of Clostridium perfringens from spores in scrapple during cooling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Scrapple is an ethnic food produced/consumed almost exclusively in the Middle Atlantic states of the U.S. It is typically made from ground pork trimmings, seasonings, cornmeal, and flour. This mixture is cooked and then shaped into loaves that are cooled and subsequently stored refrigerated until sl...

230

9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2013 CFR

...Purity test. Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from...

2013-01-01

231

An outbreak of enterotoxaemia caused by Clostridium perfringens type D in goats in Patagonia  

Microsoft Academic Search

Forty-four of a flock of 117 angora goats in the Rio Negro province of Argentina died within four days. Most of the animals died shortly after the onset of clinical signs, but in a few the clinical course lasted for several days. Post mortem the small and large intestines were filled with watery contents, blood and fibrin clots, and there

FA Uzal; MI Pasini; FV Olaechea; CA Robles; A Elizondo

1994-01-01

232

9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2012 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2012-01-01

233

9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2010 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2010-01-01

234

9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2014 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2014-01-01

235

9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2011 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2011-01-01

236

9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2012 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2012-01-01

237

9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2011 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2011-01-01

238

9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2010 CFR

... Final container samples of completed product from each serial and each subserial shall be tested for viable bacteria and fungi as provided in § 113.26. (b) Safety test. Bulk or final container samples of completed product from each serial...

2010-01-01

239

Predictive model for growth of Clostridium perfringens during cooling of cooked ground chicken  

Technology Transfer Automated Retrieval System (TEKTRAN)

Traditional methodologies for development of microbial growth models under dynamic temperature conditions do not take into account the organism’s prior history. Such models were shown to be inadequate in predicting growth of the organisms under dynamic conditions commonly encountered in the food ind...

240

Clostridium perfringens Bacteremia in an 85-Year-Old Diabetic Man  

PubMed Central

Emphysematous cholecystitis is an uncommon and dangerous complication of acute cholecystitis. Common risk factors for this disease include male gender, old age, presence of diabetes mellitus and cholelithiasis. The disease is best treated with emergent surgery and parenteral antibiotics. We present the case of an 85-year-old nursing home resident who presented to our institution with a 3-day history of gradually worsening abdominal discomfort.

Mirrakhimov, Aibek E.; Chandra, Gopika; Voore, Prakruthi; Khan, Maliha; Halytskyy, Oleksandr; Elhassan, Ahmed; Ali, Alaa M.

2014-01-01

241

9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2013 CFR

...contain 10 L+ doses per ml. (iii) Combine 1 International Unit of Standard Antitoxin... doses of diluted Standard Toxin and Combine 1 International Unit of Standard Antitoxin...serum with 1 ml of diluent (1:2) and combine 1 ml of this solution with 10 Lo...

2013-01-01

242

9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.  

Code of Federal Regulations, 2014 CFR

...contain 10 L+ doses per ml. (iii) Combine 1 International Unit of Standard Antitoxin... doses of diluted Standard Toxin and Combine 1 International Unit of Standard Antitoxin...serum with 1 ml of diluent (1:2) and combine 1 ml of this solution with 10 Lo...

2014-01-01

243

Calculation of the axial charge in the epsilon and epsilon' regimes of HBChPT  

E-print Network

The axial charge g_A is calculated in the epsilon regime of Heavy Baryon Chiral Perturbation Theory to order epsilon^3. To perform this calculation, we develop a technique to compute baryon properties in the epsilon regime of Chiral Perturbation Theory. This technique includes contributions from pion zero momentum modes and can be used at arbitrary order, diagram by diagram, in the $\\epsilon$ regime to calculate any matrix element. Also, a calculation of g_A in the epsilon' regime to order epsilon'^3 is performed. A discussion of the domain of applicability for both the epsilon and epsilon' regimes is also included.

Brian Smigielski; Joseph Wasem

2007-10-24

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

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

246

Diarylacylhydrazones: Clostridium-Selective Antibacterials with Activity Against Stationary-Phase Cells  

PubMed Central

Current antibiotics for treating Clostridium difficile infections (CDI), i.e. metronidazole, vancomycin and more recently fidaxomicin, are mostly effective but treatment failure and disease relapse remain as significant clinical problems. The shortcomings of these agents are attributed to their low selectivity for C. difficile over normal gut microflora and their ineffectiveness against C. difficile spores. This paper reports that certain diarylacylhydrazones identified during a high-throughput screening/counter-screening campaign show selective activity against two Clostridium species (C. difficile and C. perfringens) over common gut commensals. Representative examples are shown to possess activity similar to vancomycin against clinical C. difficile strains and to kill stationary-phase C. difficile cells, which are responsible for spore production. Structure-activity relationships with additional synthesised analogues suggested a protonophoric mechanism may play a role in the observed activity/selectivity and this was supported by the well-known protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) showing selective anti-Clostridium effects and activity similar to diarylacylhydrazones against stationary-phase C. difficile cells. Two diarylacylhydrazones were shown to be non-toxic towards human FaDu and Hep G2 cells indicating that further studies with the class are warranted towards new drugs for CDI. PMID:24360560

Casadei, Gabriele; Bremner, John B.; Lewis, Kim; Kelso, Michael J.

2014-01-01

247

Threonine requirement of broiler chickens during subclinical intestinal Clostridium infection.  

PubMed

The aim of this study was to determine the threonine requirement of broilers during a subclinical Clostridium infection. Three experiments were performed: experiments 1 and 2 to investigate the dose-response of threonine supplementation during infection and experiment 3 to validate the threonine requirement during infection. In each experiment, 1-d-old Ross 308 male broilers were used. An infection model was used with inoculation of Eimeria maxima and Clostridium perfringens at d 9 and 14 of age, respectively. Control birds were inoculated with saline and liver broth at d 9 and 14 of age, respectively. From d 9 of age, infected birds were fed diets differing in the standardized digestible threonine-to-lysine ratio (realized ratios experiment 1: 0.55, 0.58, 0.63, 0.69, and 0.72; realized ratios experiment 2: 0.64, 0.65, 0.67, 0.69, and 0.72; and realized ratios experiment 3: 0.63 and 0.67). Uninfected birds were fed diets with a realized Thr:Lys ratio of 0.63 in experiments 1 and 2 and of 0.63 or 0.67 in experiment 3. The incidence of lesions, lesion severity, and mortality rate of infected birds was not affected by the Thr:Lys ratio. Experiments 1 and 2 showed that the decrease in BW gain and feed intake was less severe in infected birds fed a diet with a Thr:Lys ratio of 0.69 and 0.67, respectively (not significant). Validation of the Thr:Lys ratio in experiment 3 showed that the BW gain and feed intake were higher for infected birds with a Thr:Lys ratio of 0.67 compared with infected birds with a Thr:Lys ratio of 0.63. This resulted in an increased BW gain and feed intake of 129 and 148 g, respectively, with a higher Thr:Lys ratio over a production period of 37 d. This indicates that a higher Thr:Lys ratio in infected birds improved production performance during infection with C. perfringens, although intestinal damage (incidence and lesion severity) was not affected. PMID:22334739

Star, L; Rovers, M; Corrent, E; van der Klis, J D

2012-03-01

248

Lactose-inducible system for metabolic engineering of Clostridium ljungdahlii.  

PubMed

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

Banerjee, Areen; Leang, Ching; Ueki, Toshiyuki; Nevin, Kelly P; Lovley, Derek R

2014-04-01

249

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

250

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

251

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

252

Structural relationship between DNA polymerases epsilon and epsilon* and their occurrence in eukaryotic cells.  

PubMed Central

Monoclonal antibodies raised against the N-terminal half of human DNA polymerase epsilon bind both to a large > 200 kDa form of DNA polymerase epsilon from HeLa cells and to a small 140 kDa form (DNA polymerase epsilon*) from calf thymus, while antibody against the C-terminal half binds to DNA polymerase epsilon but does not bind to DNA polymerase epsilon*. These results indicate that the two enzymes have common structural motifs in their N-terminal halves, and that DNA polymerase epsilon* is very likely derived from DNA polymerase epsilon by removal of its C-terminal half. DNA polymerase epsilon as well as DNA polymerase epsilon* was detected in extracts from cells of numerous eukaryotic species from yeast to human. The results indicate that DNA polymerase epsilon and its tendency to occur in a smaller form, DNA polymerase epsilon*, are evolutionarily highly conserved and that DNA polymerase epsilon may occur universally in proliferating eukaryotic cells. Images PMID:7862528

Uitto, L; Halleen, J; Hentunen, T; Höyhtyä, M; Syväoja, J E

1995-01-01

253

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

254

Epsilon Aurigae Eclipse 2009 - Ingress  

NASA Astrophysics Data System (ADS)

The mysterious star system epsilon Aurigae undergoes an eclipse every 27.1 years that lasts nearly two years. The most recent eclipse started during the late summer of 2009. An international campaign for observing this eclipse was created in 2006, with a web site for information and, to-date, 17 periodic newsletters for details, as well as a Yahoo forum List for immediate announcements and comments. Photometric data in the UBVRIJH bands have been submitted. Ingress occurred with first contact in the V band estimated at the second week of 2009 August and second contact estimated at 2010 mid-January. Spectroscopic data were also obtained during ingress. Spectroscopic data have been provided in the potassium I region, hydrogen alpha and beta regions and sodium D line region of the star system's spectrum. In this paper we describe details of observations and preliminary analysis during ingress and second contact. We introduce the observers and discuss plans for observing throughout totality and the end of the eclipse in 2011.

Hopkins, Jeffrey L.; Stencel, Robert E.; Leadbeater, Robin; Beckmann, Paul J.; Buil, Christian; Collins, Donald; Colombo, Tiziano; Garrel, Thierry; Gorodenski, Stanley; Gudmundsson, Snaevarr; Karlsson, Mukund Kurtadikar; Lindberg, Hans-Goran; Loughney, Des; Mauclaire, Benji; McCandless, Brian E.; Melillo, Frank J.; Miles, Richard; Pearson, Robert T.; Samolyk, Gerard; Schanne, Lothar; Strikis, Iakovos Marios; Teyssier, François; Thizy, Olivier

255

Inhibitory effect of a copper-dipeptide complex on the establishment of a Clostridium perenne strain in the intestinal tract of gnotobiotic mice.  

PubMed Central

A semisynthetic diet fed to axenic mice was found to prevent the establishment of a Clostridium perenne strain in their intestinal tract. This inhibitory effect did not occur when axenic mice were preinoculated with a strain of Clostridium difficile. The inhibitory effect was related to the presence in the intestinal contents of axenic mice of both dietary copper and a dipeptide, aspartic-epsilon-lysine. When C. difficile was inoculated into axenic mice, the dipeptide disappeared from the digesta, and C. perenne became established even in the presence of high concentrations of copper. PMID:4091557

Dubos, F; Pelissier, J P; Andrieux, C; Ducluzeau, R; Raibaud, P

1985-01-01

256

Isolation of Clostridium thermocellum auxotrophs  

SciTech Connect

The conversion of biomass of fuels and chemical feedstocks by microbial fermentation offers the potential of solving two of today's important problems: waste accumulation and exhaustion of fossil fuels. Microorganisms with the capabilities of converting biomass components such as cellulos and hemicellulose to chemicals and fuels in a single step are of particular interest. One such microorganism is Clostridium thermocellum, a thermophilic anaerobe which degrades cellulose to ethanol and organic acids. For efficient industrial use, the cellulolytic capacity of this strain must be improved by genetic means. Spontaneous and UV irradiation-induced auxotrophic mutants of Clostridium thermocellum, an anaerobic cellulolytic thermophile, were isolated after penicillin enrichment in a chemically defined medium.

Mendez, B.S.; Gomez, R.F.

1982-02-01

257

Pi Mu Epsilon New York Alpha Chapter Membership Application  

E-print Network

Pi Mu Epsilon New York Alpha Chapter Membership Application (Due by March 28, 2014) Contact dghsu opinion, should Pi Mu Epsilon focus on next year as an organization? 2) In what ways can Pi Mu Epsilon for admission to Pi Mu Epsilon in the coming years? 4) What motivates you to participate in the study

McConnell, Terry

258

Faltings plus epsilon, Wiles plus epsilon, and the Generalized Fermat Equation  

E-print Network

Faltings plus epsilon, Wiles plus epsilon, and the Generalized Fermat Equation H. Darmon September 9, 2007 Wiles' proof of Fermat's Last Theorem puts to rest one of the most famous unsolved problems celebrating Wiles' achieve- ment, one also feels a twinge of regret at Fermat's demise. Is the Holy Grail

Darmon, Henri

259

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

260

Effects of ACTIVATE™WD on Clostridium perfringens colonization and broiler performance using a necrotic enteritis model in broiler chickens  

Microsoft Academic Search

Both clinical and sub-clinical necrotic enteritis (NE) is common throughout the poultry growing areas of the world and it is estimated that the cost to the poultry industry globally is nearly $2 billion (Anonymous, 2000). In terms of loss of performance the sub-clinical form of the disease may be the most important as it has been shown to reduce FCR

M. Quiroz; C. Hofacre; J. Dibner; T. York; C. Knight; R. Gonzales; D. S. Parker

261

PREDICTIVE MODEL FOR GROWTH OF CLOSTRIDIUM PERFRINGENS AT TEMPERATURES APPLICABLE TO COOLING OF COOKED UNCURED BEEF AND CHICKEN  

Technology Transfer Automated Retrieval System (TEKTRAN)

The common methodology for developing growth models for dynamic environments is to first determine growth kinetic parameters from a series of growth experiments conducted within well-defined environments under isothermal conditions. Subsequently, secondary models are developed to evaluate the effec...

262

Multiplex PCR assay for detection of Clostridium perfringens in feces and intestinal contents of pigs and in swine feed  

Microsoft Academic Search

A multiplex polymerase chain reaction (PCR) assay, developed to detect the alpha-toxin and enterotoxin genes (cpa and cpe, respectively) of Clostridiumperfringens, was used to identify enterotoxigenic isolates of this organism from feces and intestinal contents of pigs and from feed samples from pig farms in Iowa. The organism was grown on tryptose-sulfite-cycloserine (TSC) agar, TSC agar without egg-yolk, sheep blood

Rajalakshmi Kanakaraj; D. l. Harris; J. Glenn Songer; B. Bosworth

1998-01-01

263

Spectral shape, epsilon and record selection  

Microsoft Academic Search

SUMMARY Selection of earthquake ground motions is considered with the goal of accurately estimating the response of a structure at a specied ground motion intensity, as measured by spectral acceleration at therst- mode period of the structure, Sa(T1). Consideration is given to the magnitude, distance and epsilon (? ) values of ground motions. First, it is seen that selecting records

Jack W. Baker; C. Allin Cornell

2006-01-01

264

K +p dispersion relations II. Epsilon exchange  

NASA Astrophysics Data System (ADS)

The role of epsilon exchange in KN scattering is discussed in relation to a recent K +p phase shift analysis based on partial-wave dispersion relations. The effective ? coupling constant is calculated and found to be positive, and to lie in the range 2 ? ƒ ? K overlineK ƒ ? N overlineN/4? ? 5 .

Martin, B. R.

1972-08-01

265

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

266

Epsilon-insensitive fuzzy c-regression models: introduction to epsilon-insensitive fuzzy modeling.  

PubMed

This paper introduces a new epsilon-insensitive fuzzy c-regression models (epsilonFCRM), that can be used in fuzzy modeling. To fit these regression models to real data, a weighted epsilon-insensitive loss function is used. The proposed method make it possible to exclude an intrinsic inconsistency of fuzzy modeling, where crisp loss function (usually quadratic) is used to match real data and the fuzzy model. The epsilon-insensitive fuzzy modeling is based on human thinking and learning. This method allows easy control of generalization ability and outliers robustness. This approach leads to c simultaneous quadratic programming problems with bound constraints and one linear equality constraint. To solve this problem, computationally efficient numerical method, called incremental learning, is proposed. Finally, examples are given to demonstrate the validity of introduced approach to fuzzy modeling. PMID:15369046

Leski, Jacek M

2004-02-01

267

Cloning and nucleotide sequence analysis of the colH gene from Clostridium histolyticum encoding a collagenase and a gelatinase.  

PubMed Central

The colH gene encoding a collagenase was cloned from Clostridium histolyticum JCM 1403. Nucleotide sequencing showed a major open reading frame encoding a 116-kDa protein of 1,021 amino acid residues. The deduced amino acid sequence contains a putative signal sequence and a zinc metalloprotease consensus sequence, HEXXH. A 116-kDa collagenase and a 98-kDa gelatinase were copurified from culture supernatants of C. histolyticum. While the former degraded both native and denatured collagen, the latter degraded only denatured collagen. Peptide mapping with V8 protease showed that all peptide fragments, except a few minor ones, liberated from the two enzymes coincided with each other. Analysis of the N-terminal amino acid sequence of the two enzymes revealed that their first 24 amino acid residues were identical and coincided with those deduced from the nucleotide sequence. These results indicate that the 98-kDa gelatinase is generated from the 116-kDa collagenase by cleaving off the C-terminal region, which could be responsible for binding or increasing the accessibility of the collagenase to native collagen fibers. The role of the C-terminal region in the functional and evolutional aspects of the collagenase was further studied by comparing the amino acid sequence of the C. histolyticum collagenase with those of three homologous enzymes: the collagenases from Clostridium perfringens and Vibrio alginolyticus and Achromobacter lyticus protease I. Images PMID:7961400

Yoshihara, K; Matsushita, O; Minami, J; Okabe, A

1994-01-01

268

Pi Mu Epsilon New York Alpha Chapter Membership Application  

E-print Network

Pi Mu Epsilon New York Alpha Chapter Membership Application (Due by November 21, 2014) Contact the following questions thoughtfully and specifically on a separate page. 1) What, in your opinion, should Pi Mu Epsilon focus on next year as an organization? 2) In what ways can Pi Mu Epsilon foster a good environment

McConnell, Terry

269

Spirotetronate antibiotics with anti-Clostridium activity from Actinomadura sp. 2EPS.  

PubMed

The rare actinomycetes strain 2EPS was isolated from soil and analysis of cultural, morphological characteristics, diaminopimelic acid content of its cell wall, and 16S rRNA gene sequence indicates that 2EPS belongs to genus Actinomadura. In addition, neighbor-joining phylogenetic tree also confirmed the relationships of this strain to other members of Actinomadura. A butanol extract with antibacterial activity was purified by reversed-phase chromatography to obtain three bioactive compounds, designated as compounds 1, 2 and 3. The structures of these compounds were determined using spectroscopic analysis ((1)H-NMR and (13)C-NMR) and mass spectrometric analysis (HR-TOF-MS). Compounds 1-3 were identified and found to be the same as those included in the Japanese patent number JP 09227587 for spirotetronate antibiotics and are BE-45722A (1), BE-45722B (2) and BE-45722C (3), respectively. All compounds were active against Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, and B. subtilis ATCC 6633) with low MIC values between 0.08 and 5.0 µg/ml. Moreover, both 1 and 3 also exhibited strong activity, with similar MIC values, against Clostridium perfringens S107 at 0.63 µg/ml and C. difficile 630 at 0.08 µg/ml. These results suggest the identified spirotetronate compounds may have potential in the treatment of Clostridium infections. Overall, this analysis demonstrates that rare actinomycetes are a promising source for discovery of antimicrobial compounds. PMID:25543910

Euanorasetr, Jirayut; Intra, Bungonsiri; Mongkol, Phayungsak; Chankhamhaengdecha, Surang; Tuchinda, Patoomratana; Mori, Mihoko; Shiomi, Kazuro; Nihira, Takuya; Panbangred, Watanalai

2015-02-01

270

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

271

[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

272

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

273

Revealing the Hot Side of Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

We request a small investment of 24 minutes of Spitzer time, to obtain four IRAC observations of epsilon Aurigae. A naked eye object located near Capella, epsilon Aurigae is the eclipsing binary star with the longest known orbital period, showing a single long duration (~2 yr) eclipse every 27.1 yr. For much of the last 200 years, the nature of the eclipsing object defied explanation. We recently demonstrated that epsilon Aurigae consists of a high luminosity F0 post-AGB star in orbit with a B5 V star surrounded by a solar system sized (~8 AU diameter) disk of cool, dust-dominated material. The eclipse of epsilon Aurigae is a rare event; moreover, it is a unique astrophysical opportunity, since the backlighting of the disk by the high luminosity eclipsed star reveals details that cannot be detected in similar dusty disks around single stars. The current eclipse started in August 2009 and ended in July 2011; we are now in the post-eclipse phase, when the irradiation-heated side of the disk will begin rotating into view. The goals for these observations include: (1) extend our ongoing IRAC monitoring campaign covering the current eclipse to post-eclipse visits; (2) provide a consistent, well-calibrated space-based set of IR photometry for comparison with ongoing ground-based work; and (3) use the composite results to constrain the thermal profile of the disk. A key expectation of these particular observations is to reveal the irradiation-heated portion of the disk, which will be visible on its trailing side following eclipse. Observations of this side of the disk will be crucial to test and constrain new models of disk structure. As part of our overall monitoring campaign with Spitzer, Hubble, Herschel, and numerous ground-based facilities, these proposed observations will make an important contribution to the understanding of stellar evolution in binary stars, including mass transfer and evolution studies, along with new insights into astrophysical disks and post-AGB star evolution.

Hoard, Donald; Stencel, Robert; Howell, Steve

2012-12-01

274

Epsilon Aurigae at the End of Eclipse  

NASA Astrophysics Data System (ADS)

We request a small investment of 24 minutes of Spitzer time, to obtain four IRAC observations of epsilon Aurigae. A naked eye object located near Capella, epsilon Aurigae is the eclipsing binary star with the longest known orbital period, showing a single long duration (~2 yr) eclipse every 27.1 yr. For much of the last 150 years, the nature of the eclipsing object defied explanation. We recently demonstrated that epsilon Aurigae consists of a high luminosity F0 post-AGB star in orbit with a B5 V star surrounded by a solar system sized (~8 AU diameter) disk of cool, dust-dominated material. The eclipse of epsilon Aurigae is a rare event; moreover, it is a unique astrophysical opportunity, since the backlighting of the disk by the high luminosity eclipsed star reveals details that cannot be detected in similar dusty disks around single stars. The current eclipse started in August 2009 and is expected to reach its photometric conclusion in May 2011 (with the spectroscopic conclusion as late as December 2011). The goals for these observations include: (1) extend our ongoing IRAC monitoring campaign covering the current eclipse to late-phase and post-eclipse visits; (2) provide a consistent, well-calibrated space-based set of IR photometry for comparison with ongoing ground-based work; and (3) use the composite results to constrain the thermal profile of the disk. A key expectation of these particular observations is to reveal the irradiation-heated portion of the disk, which will be visible on its trailing side following eclipse. Observations of this side of the disk will be crucial to test and constrain new models of disk structure. As part of our overall monitoring campaign with Spitzer, Hubble, Herschel, and numerous ground-based facilities, these proposed observations will make an important contribution to the understanding of stellar evolution in binary stars, including mass transfer and evolution studies, along with new insights into astrophysical disks and post-AGB star evolution.

Hoard, Donald; Stencel, R.; Howell, S.

2011-05-01

275

Nonlinear models in 2 + epsilon dimensions  

SciTech Connect

The general nonlinear scalar model is studied at asymptotically low temperature near two dimensions. The low-temperature expansion is renormalized, and effective algorithms are derived for calculation to all orders in the renormalized expansion. The renormalization group coefficients are calculated in the two-loop approximation, and topological properties of the renormalization group equations are investigated. Special attention is paid to the infrared instabilities of the fixed points, since they provide the continuum limits of the model. The model consists of a scalar field phi on Euclidean 2 + epsilon space whose values phi(x) lie in a finite-dimensional differentiable manifold. 4 figures.

Friedan, D.H.

1980-08-01

276

[Preliminary identification of clinically significant Clostridium species].  

PubMed

Preliminary identification of clinically significant Clostridium spp. is based on evaluating their microscopic and macroscopic morphology, Gram staining (Gram stain-positive structure of the bacterial wall), positive production of lecithinase, lipase and proteolytic activity on egg yolk agar, and simple chemical tests. If this preliminary identification is not sufficient, biochemical identification is performed, along with 16S-rRNA sequencing of the bacterial genome. The article comments on options of preliminary identification of clinically significant Clostridium spp. PMID:20640984

Balejová, Magda

2010-06-01

277

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

278

Classical closure theory and Lam's interpretation of epsilon-RNG  

NASA Technical Reports Server (NTRS)

Lam's phenomenological epsilon-renormalization group (RNG) model is quite different from the other members of that group. It does not make use of the correspondence principle and the epsilon-expansion procedure. We demonstrate that Lam's epsilon-RNG model is essentially the physical space version of the classical closure theory in spectral space and consider the corresponding treatment of the eddy viscosity and energy backscatter.

Zhou, YE

1995-01-01

279

Epsilon Metal Summary Report FY 2011  

SciTech Connect

The Epsilon-metal ({var_epsilon}-metal) phase was selected in FY 2009 as a potential waste form to for immobilizing the noble metals found in the undissolved solids + aqueous stream, and the soluble Tc from ion-exchange process, each resulting from proposed aqueous reprocessing. {var_epsilon}-metal phase is observed in used nuclear fuel and the natural reactors of Oklobono in Gabon, where the long-term corrosion behavior was demonstrated. This makes {var_epsilon}-metal a very attractive waste form. Last fiscal year, {var_epsilon}-metal was successfully fabricated by combining the five-metals, Mo, Ru, Rh, Pd and Re (surrogate for Tc), into pellets followed by consolidation with an arc melter. The arc melter produced fully dense samples with the epsilon structure. However, some chemistry differences were observed in the microstructure that resulted in regions rich in Re and Mo, and others rich in Pd, while Ru and Rh remained fairly constant throughout. This year, thermal stability (air), and corrosion testing of the samples fabricated by arc melting were the main focus for experimental work. Thermal stability was measured with a differential scanning calorimeter - thermogravimetric analyzer, by both ramp heating as well as step heating. There is clear evidence during the ramp heating experiment of an exothermic event + a weight loss peak both beginning at {approx}700 C. Step heating showed an oxidation event at {approx}690 C with minimal weight gain that occurs just before the weight loss event at 700 C. The conclusion being that the e-metal begins to oxidize and then become volatile. These findings are useful for considering the effects of voloxidation process. Three different pellets were subjected to electrochemical testing to study the corrosion behavior of the epsilon-metal phase in various conditions, namely acidic, basic, saline, and inert. Test was done according to an interim procedure developed for the alloy metal waste form. First an open circuit potential was measured, followed by linear polarization sweeps. The linear polarization sweep range was the Tafel equation was fit to the linear polarization sweep data to determine the corrosion rate of each pellet in each test solution. The average calculated corrosion rates of the three pellets according to solution conditions were: -1.91 x 10{sup -4} mm/yr (0.001 M NaOH), -1.48 x 10{sup -3} mm/yr (0.01 M NaCl), -8.77 x 10{sup -4} mm/yr (0.001 M H{sub 2}SO{sub 4}), -2.09 x 10{sup -3} mm/yr (0.001 M NaOH + 0.01 M NaCl), and -1.54 x 10{sup -3} mm/yr (0.001 M H{sub 2}SO{sub 4} + 0.01 M NaCl). Three single-pass flow through (SPFT) test were conducted at a flow rate of 10 ml/day, at 90 C, and pH of 2.5, 7.0, and 9.0 for up to 322 days. Results of the tests indicate that dissolution rates were 5 x 10{sup -4} g m{sup 2} d{sup -1} at pH 9.0, 1.2 x 10{sup -4} g m{sup -2} d{sup -1} at pH 7.0, and 2 x 10{sup -4} g m{sup -2} d{sup -1} at pH 2.5. The sample used for the pH 7.0 SPFT test contains extra Re compared to samples used for the other two SPFT test, which came from a single pellet. The corrosion data measured this year indicate that the {var_epsilon}-metal phase is chemically durable. The two chemically different phases, but structurally the same, behave differently during dissolution according to the microstructure changes observed in both the electrochemical and in SPFT test. Characterization of the test specimens after testing suggests that the dissolution is complex and involves oxidative dissolution followed by precipitation of both oxide and metallic phases. These data suggest that the dissolution in the electrochemical and SPFT tests is different; a process that needs further investigation.

Strachan, Denis M.; Crum, Jarrod V.; Zumhoff, Mac R.; Bovaird, Chase C.; Windisch, Charles F.; Riley, Brian J.

2011-09-30

280

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

281

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

282

Clostridium difficile in paediatric populations  

PubMed Central

An increase in Clostridium difficile infection incidence has been observed among hospitalized children in the United States. The present statement, targeted at clinicians caring for infants and children in community and institutional settings, summarizes the relevant information relating to the role of C difficile in childhood diarrhea and provides recommendations for diagnosis, prevention and treatment. Significant differences between adult and paediatric risk factors and disease are discussed, along with emerging therapies. The relationship between age and disease severity in children with a newly emergent and more fluoroqinolone-resistant strain of C difficile (North American Pulse-field type-1 [NAP1]) remains unknown. The importance of antimicrobial stewardship as a preventive strategy is highlighted. This statement replaces a previous Canadian Paediatric Society position statement on C difficile published in 2000. PMID:24627655

Allen, Upton D

2014-01-01

283

Xylanolytic activity of Clostridium acetobutylicum  

SciTech Connect

Of 20 strains of Clostridium spp. screened, 17 hydrolyzed larch wood xylan. Two strains of Clostridium acetobutylicum, NRRL B527 and ATCC 824, hydrolyzed xylan but failed to grow on solid media with larch xylan as the sole carbon source; however, strain ATCC 824 was subsequently found to grow on xylan under specified conditions in a chemostat. These two strains possessed cellulolytic activity and were therefore selected for further studies. In cellobiose-limited continuous cultures, strain NRRL B527 produced maximum xylanase activity at pH 5.2. Strain ATCC 824 produced higher xylanase, xylopyranosidase, and arabinofuranosidase activities in chemostat culture with xylose than with any other soluble carbon source as the limiting nutrient. The activities of these enzymes were markedly reduced when the cells were grown in the presence of excess glucose. The xylanase showed maximum activity at pH 5.8 to 6.0 and 65/sup 0/C. The enzyme was stable on the alkaline side of pH 5.2 but was unstable below this pH value. The extracellular xylanolytic activity from strain ATCC 824 hydrolyzed 12% of the larch wood xylan during a 24-h incubation period, yielding xylose, xylobiose, and xylotriose as the major hydrolysis products. Strain ATCC 824, after being induced to grow in batch culture in xylan medium supplemented with a low concentration of xylose, failed to grow reproducibility in unsupplemented xylan medium. A mutant obtained by mutagenesis with ethyl methanosulfonate was able to grow reproducibility in batch culture on xylan. Both the parent strain and the mutant were able to grow with xylan as the sole source of carbohydrate in continuous culture with the pH maintained at either 5.2 or 6.0. Under these conditions, the cells utilized approximately 50% of the xylan.

Lee, S.F.; Forsberg, C.W.; Gibbins, L.N.

1985-10-01

284

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, Gra?yna; Perucki, William; Mach, Tomasz

2014-01-01

285

Pi Mu Epsilon Initiation Ceremony Welcome to the second annual induction ceremony of the  

E-print Network

Pi Mu Epsilon Initiation Ceremony Welcome to the second annual induction ceremony of the New York Alpha Omicron Chapter of Pi Mu Epsilon, the National Mathematics Honor Society. Information about Pi Mu Epsilon (Janine Belsky): We are assembled here to initiate new members into Pi Mu Epsilon. Pi Mu Epsilon

Feingold, Alex

286

Inhibitory actions of ceramide upon PKC-epsilon/ERK interactions.  

PubMed

We have previously shown that interleukin-1 receptor-generated ceramide induces growth arrest in smooth muscle pericytes by inhibiting an upstream kinase in the extracellular signal-regulated kinase (ERK) cascade. Here, we now report the mechanism by which ceramide inhibits ERK activity. Ceramide renders the human embryonic kidney 293 cells (HEK 293) resistant to the mitogenic actions of growth factors and activators of protein kinase C (PKC). A role for PKC to mediate ceramide inhibition of growth factor-induced ERK activity and mitogenesis is suggested, as exogenous ceramide directly inhibits both immunoprecipitated and recombinant PKC-epsilon activities. To confirm that PKC-epsilon is necessary for ceramide-inhibited ERK activity, HEK 293 cells were transfected with a dominant-negative mutant of PKC-epsilon (DeltaPKC-epsilon). These transfected cells respond to insulin-like growth factor I (IGF-I) with a significantly decreased ERK activity that is not further reduced by ceramide treatment. Coimmunoprecipitation studies reveal that the treatment with IGF-I induces the association of ERK with PKC-epsilon but not with PKC-zeta. Ceramide treatment significantly inhibits the IGF-I-induced PKC-epsilon interaction with bioactive phosphorylated ERK. Ceramide also inhibits IGF-I-induced PKC-epsilon association with Raf-1, an upstream kinase of ERK. Together, these studies demonstrate that ceramide exerts anti-mitogenic actions by limiting the ability of PKC-epsilon to form a signaling complex with Raf-1 and ERK. PMID:11350735

Bourbon, N A; Yun, J; Berkey, D; Wang, Y; Kester, M

2001-06-01

287

A Case of Infant Botulism due to Neurotoxigenic Clostridium butyricum Type E Associated with Clostridium difficile Colitis  

Microsoft Academic Search

.   Reported here is the sixth case of intestinal toxemia botulism caused by Clostridium butyricum type E in Italy since 1984. In this case, the patient was concomitantly affected with colitis due to Clostridium difficile toxin. A review of previously reported cases revealed that some of these patients may also have had intestinal toxemia botulism\\u000a associated with Clostridium difficile colitis,

L. Fenicia; L. Da Dalt; F. Anniballi; G. Franciosa; S. Zanconato; P. Aureli

2002-01-01

288

Perturbative matching of the staggered four-fermion operators for {epsilon}'/{epsilon}  

SciTech Connect

Using staggered fermions, we calculate the perturbative corrections to the bilinear and four-fermion operators that are used in the numerical study of weak matrix elements for {epsilon}'/{epsilon}. We present results for one-loop matching coefficients between continuum operators, calculated in the naive dimensional regularization (NDR) scheme, and gauge invariant staggered fermion operators. In particular, we concentrate on Feynman diagrams of the current-current insertion type. We also present results for the tadpole improved operators. These results, combined with existing results for penguin diagrams, provide a complete one-loop renormalization of the staggered four-fermion operators. Therefore, using our results, it is possible to match a lattice calculation of K{sup 0}-{bar K}{sup 0} mixing and K{yields}{pi}{pi} decays to the continuum NDR results with all corrections of O(g{sup 2}) included.

Lee, Weonjong

2001-09-01

289

[Clostridium difficile infections. Current aspects].  

PubMed

Clostridium difficile is a gram-positive anaerobe that forms subterminal spores. It is now one of major nosocomial pathogens, mainly in older patients, because of its ability to persist in the environment and to become established in the gastrointestinal tract once the natural microflora has been modified by antibiotic therapy. Toxigenic strains of C. difficile produce toxin A (enterotoxin) or toxin B (cytotoxin) or both with cause the cytotoxic effect "rounding". C. difficile can spread from patient to patient and, probably, the primary way by which the organism is spread is by health care workers. C. difficile causes intestinal diseases ranging by mild diarrhea (antibiotic associated diarrhea) to fatal pseudomembranous colitis (PMC). The current therapy is based on oral administration of metronidazole or vancomycin . In patients non responders or that continue to relapse can be used other forms of therapy: antibiotic (teicoplanine, bacitracine, rifamixine); anion exchange resin (colestipol, colestiramine); probiotic therapy (S. boulardii, lactobacilli and fecal enemas). New and improved studies will lead to new and better ways of treating patients and better understanding of this unusual pathogen and how it causes diseases. PMID:9691734

Fulgione, V

1998-01-01

290

Treatment of Clostridium difficile infection.  

PubMed

The treatment options for Clostridium difficile infection remain limited, although promising agents are currently being assessed. Metronidazole is the first-line drug of choice for those patients requiring specific anti-C. difficile treatment. Much of the interest in alternative therapies has centred on the difficult management issues posed by patients with multiple symptomatic recurrences of C. difficile infection. However, it is now clear that the majority of these episodes are due to reinfections with new C. difficile strains and not relapses caused by the original bacterium. Hence, the true efficacy of the alternative regimens remains unclear. Individuals susceptible to C. difficile reinfections need to be protected from exposure to C. difficile until their bowel flora recovers. While several biotherapeutic approaches to the treatment and prevention of C. difficile infection have been described, few controlled data are available. Preliminary studies with anti-C. difficile bovine immunoglobulin concentrates for treatment and prevention have produced promising results. Vaccination to prevent C. difficile infection, particularly in high-risk elderly patients managed within institutions where C. difficile is endemic, is a worthwhile therapeutic goal. PMID:9630373

Wilcox, M H

1998-05-01

291

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

292

Hydrophobicity of Bacillus and Clostridium spores.  

PubMed Central

The hydrophobicities of spores and vegetative cells of several species of the genera Bacillus and Clostridium were measured by using the bacterial adherence to hexadecane assay and hydrophobic interaction chromatography. Although spore hydrophobicity varied among species and strains, the spores of each organism were more hydrophobic than the vegetative cells. The relative hydrophobicities determined by the two methods generally agreed. Sporulation media and conditions appeared to have little effect on spore hydrophobicity. However, exposure of spore suspensions to heat treatment caused a considerable increase in spore hydrophobicity. The hydrophobic nature of Bacillus and Clostridium spores suggests that hydrophobic interactions may play a role in the adhesion of these spores to surfaces. PMID:2275528

Wiencek, K M; Klapes, N A; Foegeding, P M

1990-01-01

293

A four-iron, four-sulfide ferredoxin with high thermostability from Clostridium thermoaceticum.  

PubMed Central

A ferredoxin containing only one [Fe4S4] cluster was purified from Clostridium thermoaceticum. It has a molecular weight of about 7,300, a partial specific volume of 0.67, and an isoelectric point of 3.25. Its absorption spectrum has two maxima at 390 nm (epsilon = 16.8 X 10(3)M-1cm-1) and at 280 nm (epsilon = 24.2 X 10(3)M-1cm-1). The absorption at 390 nm is almost half that of other clostridial ferredoxins, which have two [Fe4S4] clusters, and is similar to other ferredoxins with only one [Fe4S4] cluster. The ferredoxin had high thermal stability and retained over 50% of its activity after treatment at 80 degrees C. It functions in the transfer of electrons from pyruvate to nicotinamide adenine dinucleotide phosphate (NADP), which indicates the presence of pyruvate:ferredoxin oxidoreductase and reduced ferredoxin-NADP reductase in C, thermoaceticum. NADPH is used in the synthesis of acetate from CO2 in this organism. PMID:863852

Yang, S S; Ljungdahl, L G; LeGall, J

1977-01-01

294

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

295

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

296

Quantum critical metals in $4-\\epsilon$ dimensions  

E-print Network

We study the quantum theory of a Fermi surface coupled to a gapless boson scalar in $D=4-\\epsilon$ spacetime dimensions as a simple model for non-Fermi liquids (NFL) near a quantum phase transition. Our analysis takes into account the full backreaction from Landau damping of the boson, and obtains an RG flow that proceeds through three distinct stages. Above the scale of Landau damping the Fermi velocity flows to zero, while the coupling evolves according to its classical dimension. Once damping becomes important, its backreaction leads to a crossover regime where dynamic and static damping effects compete and the fermion self-energy does not respect scaling. Below this crossover and having tuned the boson to criticality, the theory flows to a $z=3$ scalar interacting with a NFL. By increasing the number of bosonic flavors, the phase diagram near the quantum critical point interpolates between a superconducting dome fully covering the NFL behavior, and a phase where NFL effects become important first, before ...

Torroba, Gonzalo

2014-01-01

297

Clostridium difficile phages: still difficult?  

PubMed Central

Phages that infect Clostridium difficile were first isolated for typing purposes in the 1980s, but their use was short lived. However, the rise of C. difficile epidemics over the last decade has triggered a resurgence of interest in using phages to combat this pathogen. Phage therapy is an attractive treatment option for C. difficile infection, however, developing suitable phages is challenging. In this review we summarize the difficulties faced by researchers in this field, and we discuss the solutions and strategies used for the development of C. difficile phages for use as novel therapeutics. Epidemiological data has highlighted the diversity and distribution of C. difficile, and shown that novel strains continue to emerge in clinical settings. In parallel with epidemiological studies, advances in molecular biology have bolstered our understanding of C. difficile biology, and our knowledge of phage–host interactions in other bacterial species. These three fields of biology have therefore paved the way for future work on C. difficile phages to progress and develop. Benefits of using C. difficile phages as therapeutic agents include the fact that they have highly specific interactions with their bacterial hosts. Studies also show that they can reduce bacterial numbers in both in vitro and in vivo systems. Genetic analysis has revealed the genomic diversity among these phages and provided an insight into their taxonomy and evolution. No strictly virulent C. difficile phages have been reported and this contributes to the difficulties with their therapeutic exploitation. Although treatment approaches using the phage-encoded endolysin protein have been explored, the benefits of using “whole-phages” are such that they remain a major research focus. Whilst we don’t envisage working with C. difficile phages will be problem-free, sufficient study should inform future strategies to facilitate their development to combat this problematic pathogen. PMID:24808893

Hargreaves, Katherine R.; Clokie, Martha R. J.

2014-01-01

298

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

299

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

300

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

301

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

302

Clostridium acidurici Electron-Bifurcating Formate Dehydrogenase  

PubMed Central

Cell extracts of uric acid-grown Clostridium acidurici catalyzed the coupled reduction of NAD+ and ferredoxin with formate at a specific activity of 1.3 U/mg. The enzyme complex catalyzing the electron-bifurcating reaction was purified 130-fold and found to be composed of four subunits encoded by the gene cluster hylCBA-fdhF2. PMID:23872566

Wang, Shuning; Huang, Haiyan; Kahnt, Jörg

2013-01-01

303

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

304

Infrared Studies of Epsilon Aurigae in Eclipse  

NASA Astrophysics Data System (ADS)

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., Jr.; Hopkins, Jeffrey L.; Howell, Steve B.; Hoard, D. W.; Rayner, John; Bus, Schelte; Tokunaga, Alan; Sitko, Michael L.; Bradford, Suellen; Russell, Ray W.; Lynch, David K.; Hammel, Heidi; Whitney, Barbara; Orton, Glenn; Yanamandra-Fisher, Padma; Hora, Joseph L.; Hinz, Philip; Hoffmann, William; Skemer, Andrew

2011-11-01

305

Correlations between epsilon'\\/epsilon and Rare K Decays in the Littlest Higgs Model with T-Parity  

Microsoft Academic Search

We calculate the CP-violating ratio epsilon'\\/epsilon in the Littlest Higgs\\u000amodel with T-parity (LHT) and investigate its correlations with the branching\\u000aratios for K_L -> pi^0 nu {bar nu}, K_L -> pi^0 l^+ l^- and K^+ -> pi^+ nu {bar\\u000anu}. The resulting correlations are rather strong in the case of K_L decays,\\u000abut less pronounced in the case of

Monika Blanke; Andrzej J. Buras; Stefan Recksiegel; Cecilia Tarantino; Selma Uhlig

2007-01-01

306

Complete Genome Sequence of Clostridium clariflavum DSM 19732  

SciTech Connect

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 proteincoding and 98 RNA genes, for the type strain DSM 19732.

Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Davenport, Karen W. [Los Alamos National Laboratory (LANL); Teshima, Hazuki [Los Alamos National Laboratory (LANL); Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Han, James [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lynd, Lee R [Thayer School of Engineering at Dartmouth

2012-01-01

307

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

308

The activity of glutaraldehyde against Clostridium difficile.  

PubMed

The sporicidal activity of 2% glutaraldehyde against Bacillus subtilis var. globigii and Bacillus stearothermophilus was compared with that against Clostridium difficile. The aerobic species, normally chosen for test purposes, survived for 2 h but Cl. difficile was killed in under 10 min. In view of the impractical and lengthy immersions required to satisfy standard tests using non-pathogenic spores, a less stringent standard would probably be more appropriate. PMID:2859321

Dyas, A; Das, B C

1985-03-01

309

The cellulolytic system of Clostridium cellulolyticum  

Microsoft Academic Search

Recent findings on the cellulolytic system of the mesophilic Clostridium cellulolyticum are reviewed. Six cellulases and the scaffolding protein, which are, at the present time, the known components of the cellulosome have been cloned. The catalytic and structural properties of the cloned enzymes CelA, CelC, CelD and CelF are described. It was shown that the grafting of the cellulases onto

Jean-pierre Bélaich; Chantal Tardif; Anne Bélaich; Christian Gaudin

1997-01-01

310

Studies on cellulase production by Clostridium thermocellum  

Microsoft Academic Search

Clostridium thermocellum ATCC 27405 (and its improved cellulase-producing mutant, AS-39) is an anaerobic thermophile that produces endo-ß-glucanase and exo-ß-glucanase when grown on cellobiose or cellulose as major carbon source (Shinmyo et al. 1979). The site of cellulase accumulation was at least 95% extracellular. Optimum conditions for endo-ß-glucanase production in flasks included 1% (w\\/v) cellobiose, 0.2% (w\\/v) urea as a nitrogen

D. V. Garcia-Martinez; A. Shinmyo; A. Madia; A. L. Demain

1980-01-01

311

Draft Genome Sequence of Clostridium butyricum Strain NOR 33234, Isolated from an Elderly Patient with Diarrhea  

PubMed Central

Clostridium butyricum is one of the species frequently present in patients’ stool samples. However, the identification of this species is sometimes difficult. Here, we present the draft genome of Clostridium butyricum NOR 33234, which was isolated from a patient with suspected Clostridium difficile infection-associated diarrhea and resembles Clostridium clostridioforme in biochemical tests. PMID:25540356

Kwok, Jamie S. L.; Ip, Margaret; Chan, Ting-Fung; Lam, Wai-Yip

2014-01-01

312

Parasitic gastroenteritis in lambs widespread.  

PubMed

Parasitic gastroenteritis diagnosed in lambs by all veterinary investigation centres Clostridium perfringens epsilon enterotoxaemia suspected in two cows Comparative quarterly porcine reproductive and respiratory syndrome diagnoses reach a 10-year peak Failure of an entire colony of gulls in Cumbria Endoparasitism the predominant feature in exotic farmed animals These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for September 2014. PMID:25614548

2015-01-24

313

An Atypical Clostridium Strain Related to the Clostridium botulinum Group III Strain Isolated from a Human Blood Culture  

PubMed Central

A nontoxigenic strain isolated from a fatal human case of bacterial sepsis was identified as a Clostridium strain from Clostridium botulinum group III, based on the phenotypic characters and 16S rRNA gene sequence, and was found to be related to the mosaic C. botulinum D/C strain according to a multilocus sequence analysis of 5 housekeeping genes. PMID:24088855

Ruimy, Raymond; Bouchier, Christiane; Faucher, Nathalie; Mazuet, Christelle; Popoff, Michel R.

2014-01-01

314

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

315

Closure generation based on viewing LAMBDA as EPSILON plus COMPILE  

E-print Network

Closure generation based on viewing LAMBDA as EPSILON plus COMPILE Marc Feeley Computer Science (Canada) Abstract This paper describes a way of expressing {expressions (which produce closures) in terms of {expressions and closure generation. It also leads to an e cient closure implementation both in time and space

Feeley, Marc

316

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

317

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

318

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

319

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

320

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

321

Development of an antigen-capture enzyme-linked immunosorbent assay for Clostridium perfringens beta2-toxin in porcine feces and the neonatal piglet intestine.  

PubMed

An enzyme-linked immunosorbent assay (ELISA) was developed for detection and quantitation of beta2-toxin in neonatal piglet intestinal contents. Polystyrene plates were coated with polyclonal capture antibodies prepared against consensus recombinant beta2-toxin. The ELISA was developed using consensus recombinant beta2-toxin, atypical recombinant beta2-toxin, purified consensus native beta2-toxin, and field samples of neonatal porcine intestinal contents. Captured antigen was detected using a horseradish peroxidase-labeled monoclonal antibody against consensus recombinant beta2-toxin. The limit of detection of the ELISA for consensus beta2-toxin was between 2.0 and 3.5 ng/ml. The ELISA detected atypical recombinant beta2-toxin only weakly. Optical density was protein concentration dependent. The test confirmed differences between consensus and atypical recombinant beta2-toxin, but similar results obtained when testing pure consensus recombinant beta2-toxin and native beta2-toxin. Results obtained from intestinal content samples, particularly from the small intestine, were highly inconsistent and suggested variable protease activity. Addition of protease inhibitors partially prevented degradation of the toxin; however, sample processing at low temperature, at a lower pH (citrate buffer with 5% of bovine serum albumin, pH 6.1), and "cold incubation" of applied antigens abolished protease activity. The recombinant toxin was preserved in spiked intestinal samples by freezing at -70°C, suggesting that necropsy samples can be stored frozen for periodic testing. With appropriate sample preparation, antigen-capture ELISA can detect beta2-toxin in the intestinal content and feces of neonatal piglets. PMID:22855377

Kircanski, Jasmina; Hodgins, Douglas; Soltes, Glenn; Pei, Yanlong; Parreira, Valeria R; Songer, J Glenn; Prescott, John F

2012-09-01

322

Synthesis and characterization of shape memory poly (epsilon-caprolactone) polyurethane-ureas.  

E-print Network

??A series of segmented poly (epsilon-caprolactone) polyurethane-ureas (PCLUUs) were prepared from poly (epsilon-caprolactone) (PCL) diol, different dissociates and chain extenders to improve the recovery stress… (more)

Ren, Hongfeng

2012-01-01

323

Antibodies for Treatment of Clostridium difficile Infection  

PubMed Central

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

Wilcox, Mark H.

2014-01-01

324

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

325

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

326

Association of apolipoprotein E allele {epsilon}4 with late-onset sporadic Alzheimer`s disease  

SciTech Connect

Apolipoprotein E, type {epsilon}4 allele (ApoE {epsilon}4), is associated with late-onset sporadic Alzheimer`s disease (AD) in French patients. The association is highly significant (0.45 AD versus 0.12 controls for {epsilon}4 allele frequencies). These data support the involvement of ApoE {epsilon}4 allele as a very important risk factor for the clinical expression of AD. 22 refs., 1 fig., 3 tabs.

Lucotte, G.; David, F.; Berriche, S. [Regional Center of Neurogenetics, Reims (France)] [and others

1994-09-15

327

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

328

Secretion of clostridium cellulase by E. coli  

DOEpatents

A gene, encoding an endocellulase from a newly isolated mesophilic Clostridium strain IY-2 which can digest bamboo fibers, cellulose, rice straw, and sawdust, was isolated by shotgun cloning in an E. coli expression plasmid pLC2833. E. coli positive clones were selected based on their ability to hydrolyze milled bamboo fibers and cellulose present in agar plates. One clone contained a 2.8 kb DNA fragment that was responsible for cellulase activity. Western blot analyses indicated that the positive clone produced a secreted cellulase with a mass of about 58,000 daltons that was identical in size to the subunit of one of the three major Clostridium cellulases. The products of cellulose digestion by this cloned cellulase were cellotetraose and soluble higher polymers. The cloned DNA contained signal sequences capable of directing the secretion of heterologous proteins from an E. coli host. The invention describes a bioprocess for the treatment of cellulosic plant materials to produce cellular growth substrates and fermentation end products suitable for production of liquid fuels, solvents, and acids.

Yu, Ida Kuo (1885 California St., #62, Mountain View, CA 94041)

1998-01-01

329

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

330

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

331

Clostridium difficile: A Cause of Diarrhea in Children  

MedlinePLUS

ADVICE FOR PATIENTS Clostridium difficile : A Cause of Diarrhea in Children C lostridium difficile is a bacterium ... the most common cause of health care–associated diarrhea in the United States. While most health care– ...

332

The epsilon Aurigae Secondary: A Hydrostatically Supported Disk  

Microsoft Academic Search

Epsilon Aurigae is an F supergiant in a spectroscopic binary system that undergoes a flat-bottomed partial eclipse of 2 yr duration every 27 yr. The spectrum appears to be single-lined, aside from extra absorption features detected during and shortly after eclipse. Eclipse characteristics indicate that the secondary is a very elongated object 5-10 AU in dimension parallel to its orbit.

Jack J. Lissauer; Scott J. Wolk; Caitlin A. Griffith; Dana E. Backman

1996-01-01

333

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

334

The effect of probiotics on Clostridium difficile diarrhea.  

PubMed

Clostridium difficile is the leading cause of nosocomially acquired intestinal infection in the United States, affecting virtually all cases of pseudomembranous colitis and up to 20% of cases of antibiotic-associated diarrhea. Even after receiving antibiotic treatment with either metronidazole or vancomycin, 20% of patients will have recurrent Clostridium difficile diarrhea. An innovative approach to the problem involves the introduction of competing, nonpathogenic (probiotic) organisms into the intestinal tract to restore microbial balance. The theoretical premise behind this approach is that the protective intestinal microflora is damaged by antibiotic treatment; the initial antibiotic exposure thus leaves the host susceptible to colonization and subsequent infection by Clostridium difficile. A so-called "second-hit" to the intestinal microflora occurs when the infected host is treated with flagyl or vancomycin, further destroying susceptible bacterial flora. Probiotic agents, such as Lactobacillus GG and Saccharomyces boulardii, have been studied for the treatment of Clostridium difficile. We are currently running a prospective, randomized, placebo-controlled trial of Lactobacillus GG in combination with standard antibiotics for the treatment of Clostridium difficile infection. Although it is too early to draw statistically significant conclusions, two patterns seem to be emerging: Lactobacillus GG is effective in reducing the 3-wk recurrence rate of Clostridium difficile, and patients feel better when taking Lactobacillus GG, as compared with the placebo, with early disappearance of abdominal cramps and diarrhea. In conclusion, the use of probiotics for the treatment of primary and recurrent Clostridium difficile diarrhea looks promising. Patients seem to have less recurrent Clostridium difficile diarrhea and early symptomatic improvement when using the probiotic Lactobacillus GG. PMID:10634221

Pochapin, M

2000-01-01

335

Clostridium difficile: clinical disease and diagnosis.  

PubMed Central

Clostridium difficile is an opportunistic pathogen that causes a spectrum of disease ranging from antibiotic-associated diarrhea to pseudomembranous colitis. Although the disease was first described in 1893, the etiologic agent was not isolated and identified until 1978. Since clinical and pathological features of C. difficile-associated disease are not easily distinguished from those of other gastrointestinal diseases, including ulcerative colitis, chronic inflammatory bowel disease, and Crohn's disease, diagnostic methods have relied on either isolation and identification of the microorganism or direct detection of bacterial antigens or toxins in stool specimens. The current review focuses on the sensitivity, specificity, and practical use of several diagnostic tests, including methods for culture of the etiologic agent, cellular cytotoxicity assays, latex agglutination tests, enzyme immunoassay systems, counterimmunoelectrophoresis, fluorescent-antibody assays, and polymerase chain reactions. PMID:8358706

Knoop, F C; Owens, M; Crocker, I C

1993-01-01

336

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

337

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

338

Clostridium difficile binary toxin (CDT) and diarrhea.  

PubMed

Clostridium difficile is a major enteropathogen of humans. It produces two main virulence factors, toxins A and B. A third, less well known toxin, C. difficile toxin (CDT), is a binary toxin composed of distinct enzymatic (CdtA) and cell binding/translocation (CdtB) proteins. We used a novel enzyme linked immunoassay (EIA) to detect CdtB protein in feces and culture fluids. Additionally, PCR was used to assay C. difficile isolates from fecal samples for the CDT locus (CdtLoc). Although the results from 80 isolates suggest no relationship between toxin concentrations in situ and in vitro, there is a good correlation between PCR detection of the cdtB gene and EIA detection of CdtB protein in vitro. Possible implications of the detection of CDT in patients are discussed. PMID:21376825

Carman, Robert J; Stevens, Adam L; Lyerly, Matthew W; Hiltonsmith, Megan F; Stiles, Bradley G; Wilkins, Tracy D

2011-08-01

339

Patho-genetics of Clostridium chauvoei.  

PubMed

The genomic sequence of Clostridium chauvoei, the etiological agent of blackleg, a severe disease of ruminants with high mortality specified by a myonecrosis reveals a chromosome of 2.8 million base-pairs and a cryptic plasmid of 5.5 kilo base-pairs. The chromosome contains the main pathways like glycolysis/gluconeogenesis, sugar metabolism, purine and pyrimidine metabolisms, but the notable absence of genes of the citric acid cycle and deficient or partially deficient amino acid metabolism for Histidine, Tyrosine, Phenylalanine, and Tryptophan. These essential amino acids might be acquired from host tissue damage caused by various toxins and by protein metabolism that includes 57 genes for peptidases, and several ABC transporters for amino acids import. PMID:25445013

Frey, Joachim; Falquet, Laurent

2014-11-01

340

Characterization of endoglucanase A from Clostridium cellulolyticum.  

PubMed Central

A construction was carried out to obtain a high level of expression in Escherichia coli of the gene celCCA, coding for the endoglucanase A from Clostridium cellulolyticum (EGCCA). The enzyme was purified in two forms with different molecular weights, 51,000 and 44,000. The smaller protein was probably the result of proteolysis, although great care was taken to prevent this process from occurring. Evidence was found for the loss of the conserved reiterated domains which are characteristic of C. thermocellum and C. cellulolyticum cellulases. The two forms were extensively studied, and it was demonstrated that although they had the same pH and temperature optima, they differed in their catalytic properties. The truncated protein gave the more efficient catalytic parameters on carboxymethyl cellulose and showed improved endoglucanase characteristics, whereas the intact enzyme showed truer cellulase characteristics. The possible role of clostridial reiterated domains in the hydrolytic activity toward crystalline cellulose is discussed. Images FIG. 2 PMID:1744052

Fierobe, H P; Gaudin, C; Belaich, A; Loutfi, M; Faure, E; Bagnara, C; Baty, D; Belaich, J P

1991-01-01

341

Purification and characterization of Clostridium difficile toxin.  

PubMed Central

Recent evidence indicates that toxigenic Clostridium difficile strains are a major cause of antimicrobial-associated ileocecitis in laboratory animals and pseudomembranous colitis in humans. C. difficile ATCC 9689 was cultivated in a synthetic medium to which 3% ultrafiltrated proteose peptone was added. Purification of the toxin from broth filtrate was accomplished through ultrafiltration (100,000 nominal-molecular-weight-limit membrane), precipitation with 75% (NH4)2SO4, and chromatographic separation using Bio-Gel A 5m followed by ion-exchange chromatography on a diethylaminoethyl-Sephadex A-25 column. The purified toxin displayed only one band on polyacrylamide gel electrophoresis, and approximately 170 pg was cytopathic for human amnion cells. The isolated toxin was neutralized by Clostridium sordelli antitoxin, heat labile (56 degrees C for 30 min), and inactivated at pH 4 and 9; it had an isoelectric point of 5.0, increased vascular permeability in rabbits, and caused ileocecitis in hamsters when injected intracecally. Treatment of the toxin with trypsin, chymotrypsin, pronase, amylase, or ethylmercurithiosalicylate caused inactivation, whereas lipase had no effect. By gel filtration, its molecular weight was estimated as 530,000. Upon reduction and denaturation, the toxin dissociated into 185,000- and 50,000-molecular-weight components, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Extensive dissociation yielded only the 50,000-molecular-weight component. The toxin appears to be protoplasmic and is released into the surrounding environment upon autolysis of the cells. Attempts to correlate specific enzymatic activity with the toxin have been unsuccessful. These studies will help delineate the role of C. difficile toxin in antimicrobial-associated colitis and diarrhea. Images PMID:478634

Rolfe, R D; Finegold, S M

1979-01-01

342

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

343

Protein-DNA interactions in the epsilon-globin gene silencer.  

PubMed

The developmental control of expression of the human epsilon-globin gene appears to be mediated, at least in part, by a transcriptional silencer in the DNA 5' to the cap site of this gene. We have used site-directed mutagenesis and DNA-protein binding assays to define the active motifs of this epsilon-globin silencer. DNase I foot-printing of the silencer region with K562 cell nuclear extracts defined a sequence, which we designate as the epsilon-globin silencer motif or epsilon GSM (epsilon -278 to -258 base pairs (bp)) containing a region (epsilon -270 to -258) with 90% homology to the yeast mating type silencer, ABF-1 (autonomous replicating sequence binding factor one) and which also overlaps at (epsilon -269 to -262) with the human YY1 consensus sequence, an element which mediates transcription repression and activation of viral, mouse, and human genes. The DNase I footprint extended 5' in the silencer region to include an inverted repeat of a six-nucleotide motif (epsilon -267 to -278 bp) which shares 5 of 6 bases with the GATA-1 consensus sequence. In gel mobility shift assays, two specific proteins (A and B) in nuclear extracts from erythroleukemia K562 cells bound to the DNase I-footprinted region. Protein B, associated with epsilon-globin silencer activity in vitro, required an intact epsilon GSM sequence for binding. Mutation of 5 bases within the epsilon GSM in an epsilon-globin promoter-containing fragment extending upstream to 1400 bp in transient transfection assays increased activity by 3.0-fold compared with the native sequence, suggesting that the silencer activity was mediated by the epsilon GSM sequence. We found that protein A could be displaced by a competitor containing the GATA-1 consensus sequence, suggesting that protein A is a GATA-like protein. The region from -267 to -271 within the epsilon GSM and GATA-1 homology region was important for binding of both proteins A and B. These data suggest that protein binding to the epsilon GSM and GATA motifs mediate the negative effect of the silencer on transcription, possibly via direct competition for binding to this DNA region. Recombinant yeast ABF-1 and human YY1 bound to the epsilon GSM. Mutating three bases (epsilon -259, -262, -264) in the epsilon GSM decreased the binding affinity of protein B and recombinant human YY1 but increased the binding affinity of recombinant yeast ABF-1. Furthermore, competitor containing the YY1 consensus sequence competed for protein B binding, whereas competitor containing a perfect yeast ABF-1 consensus sequence did not.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8429019

Peters, B; Merezhinskaya, N; Diffley, J F; Noguchi, C T

1993-02-15

344

The 1982-1984 Eclipse of Epsilon Aurigae  

NASA Technical Reports Server (NTRS)

A workshop proceedings concerned with the new data collected during the 1982-1984 eclipse period of the 27-year system Epsilon Aurigae is presented. This binary star has been a classic problem in astrophysics because the opaque eclipsing object is nonstellar, and probably disk shaped. Invited papers concerning the history of the system, optical, infrared and ultraviolet photometry, optical polarimetry and ultraviolet spectroscopy are included. An invited paper concerning comprehensive theoretical interpretation in the context of stellar evolution also is included. The information collected herein is unparalleled in scope and will remain a standard reference until the next eclipse cycle in the year 2009 A.D., in all probability.

Stencel, R. E. (editor)

1985-01-01

345

Light focusing using epsilon-near-zero metamaterials  

SciTech Connect

We present a strategy of focusing light using epsilon-near-zero metamaterials with embedded dielectric cylinder. The focusing mechanism is analytically investigated, and its accuracy is substantiated by rigorous full-wave simulations. It is found that the focusing intensity is highly depend on the embedded medium and its size, and the magnetic field amplitude of the focused beam itself can reach as high as 98.2 times the incident field. Owing to its versatility, the proposed light focusing system is sure to find applications in fields such as bio-sensing and in nonlinear optics.

Zhu, Weiren, E-mail: weiren.zhu@monash.edu; Premaratne, Malin [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria 3800 (Australia)] [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria 3800 (Australia); Si, Li-Ming, E-mail: lms@bit.edu.cn [Beijing Key Laboratory of Millimeter Wave and Terahertz Technology, Department of Electronic Engineering, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081 (China)] [Beijing Key Laboratory of Millimeter Wave and Terahertz Technology, Department of Electronic Engineering, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081 (China)

2013-11-15

346

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

347

Inositol Hexakisphosphate-dependent Processing of Clostridium sordellii Lethal Toxin and Clostridium novyi ?-Toxin*  

PubMed Central

Clostridium sordellii lethal toxin and Clostridium novyi ?-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (?-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP6) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP6 (<1 ?m), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi ?-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and ?-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of ?-toxin) were identified. Affinity of the CPDs for binding InsP6 was determined by isothermal titration calorimetry. In contrast to full-length toxin B and ?-toxin, autocatalytic cleavage and InsP6 binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi ?-toxin are InsP6-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP6 and subsequent processing of the toxin. PMID:21385871

Guttenberg, Gregor; Papatheodorou, Panagiotis; Genisyuerek, Selda; Lü, Wei; Jank, Thomas; Einsle, Oliver; Aktories, Klaus

2011-01-01

348

Phylogeny of the ammonia-producing ruminal bacteria Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum sp. nov  

NASA Technical Reports Server (NTRS)

In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS).

Paster, B. J.; Russell, J. B.; Yang, C. M.; Chow, J. M.; Woese, C. R.; Tanner, R.

1993-01-01

349

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

350

Comparing the identification of Clostridium spp. by two Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectrometry platforms to 16S rRNA PCR sequencing as a reference standard: A detailed analysis of age of culture and sample preparation.  

PubMed

We compared the identification of Clostridium species using mass spectrometry by two different Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) platforms (Bruker MS and Vitek MS) against 16S rRNA sequencing as the reference standard. We then examined the impact of different sample preparations and (on one of those platforms) age of bacterial colonial growth on the performance of the MALDI-TOF MS systems. We identified 10 different species amongst the 52 isolates by 16S rRNA sequencing, with Clostridium perfringens the most prevalent (n = 30). Spectrometric analysis using Vitek MS correctly speciated 47/52 (90.4%) isolates and was not affected by the sample preparation used. Performance of the Bruker MS was dependent on sample preparation with correct speciation obtained for 36 of 52 (69.2%) isolates tested using the Direct Transfer [DT] protocol, but all 52 (100%) isolates were correctly speciated using either an Extended Direct Transfer [EDT] or a Full Formic Extraction [EX] protocol. We then examined the effect of bacterial colonial growth age on the performance of Bruker MS and found substantial agreement in speciation using DT (Kappa = 0.62, 95% CI: 0.46-0.75), almost perfect agreement for EDT (Kappa = 0.94, 95% CI: 0.86-1.00) and exact agreement for EX (Kappa = 1.00) between different days. PMID:25230331

Chean, Roy; Kotsanas, Despina; Francis, Michelle J; Palombo, Enzo A; Jadhav, Snehal R; Awad, Milena M; Lyras, Dena; Korman, Tony M; Jenkin, Grant A

2014-12-01

351

Stability of explicit Navier-Stokes procedures using k-epsilon and k-epsilon/algebraic Reynolds stress turbulence models  

NASA Astrophysics Data System (ADS)

A numerical stability analysis is presented for the discrete coupled system of seven governing equations for a 3D Navier-Stokes procedure applicable to compressible turbulent flows. The relative importance of grid stretching, rotation, and turbulence source terms, as well as of effective diffusivity, on the stability of the scheme is addressed in light of order-of-magnitude arguments for such internal flows as those of turbomachine applications. The feasibility of incorporating a two-equation k-epsilon turbulence model in an explicit time-marching scheme is noted, where certain numerical-stability constraints are enforced.

Kunz, Robert F.; Lakshminarayana, Budugur

1992-11-01

352

Enhanced butanol production by coculture of Clostridium beijerinckii and Clostridium tyrobutyricum.  

PubMed

Cocultures of Clostridium beijerinckii and Clostridium tyrobutyricum in free-cell and immobilized-cell fermentation modes were investigated as a means of enhancing butanol production. The immobilized fermentation was performed in a fibrous-bed bioreactor (FBB). The results demonstrated that two-strain coculture significantly enhanced butanol production, yield and volumetric productivity compared with those in pure culture with or without butyric acid. Further, continuous immobilized-cell cocultures in two FBBs using glucose, cassava starch, or cane molasses were conducted at a dilution rate of 0.144 h(-1). The butanol production (6.66 g/L), yield (0.18 g/g), and productivity (0.96 g/L/h) were obtained with cassava starch as the substrate. Meanwhile, the acetone-butanol-ethanol (ABE) yield (0.36 g/g) was the highest among all processes investigated, suggesting that this continuous coculture mode may be suitable for industrial ABE production with no need for repeated sterilization and inoculation. PMID:23819976

Li, Lin; Ai, Hongxia; Zhang, Shexi; Li, Shuang; Liang, Zexin; Wu, Zhen-Qiang; Yang, Shang-Tian; Wang, Ju-Fang

2013-09-01

353

Clostridium beijerinckii and Clostridium difficile Detoxify Methylglyoxal by a Novel Mechanism Involving Glycerol Dehydrogenase  

PubMed Central

In contrast to gram-negative bacteria, little is known about the mechanisms by which gram-positive bacteria degrade the toxic metabolic intermediate methylglyoxal (MG). Clostridium beijerinckii BR54, a Tn1545 insertion mutant of the NCIMB 8052 strain, formed cultures that contained significantly more (free) MG than wild-type cultures. Moreover, BR54 was more sensitive to growth inhibition by added MG than the wild type, suggesting that it has a reduced ability to degrade MG. The single copy of Tn1545 in this strain lies just downstream from gldA, encoding glycerol dehydrogenase. As a result of antisense RNA production, cell extracts of BR54 possess significantly less glycerol dehydrogenase activity than wild-type cell extracts (H. Liyanage, M. Young, and E. R. Kashket, J. Mol. Microbiol. Biotechnol. 2:87–93, 2000). Inactivation of gldA in both C. beijerinckii and Clostridium difficile gave rise to pinpoint colonies that could not be subcultured, indicating that glycerol dehydrogenase performs an essential function in both organisms. We propose that this role is detoxification of MG. To our knowledge, this is the first report of targeted gene disruption in the C. difficile chromosome. PMID:11319074

Liyanage, Hemachandra; Kashket, Shelby; Young, Michael; Kashket, Eva R.

2001-01-01

354

Comparative In Vitro Activities of SMT19969, a New Antimicrobial Agent, against 162 Strains from 35 Less Frequently Recovered Intestinal Clostridium Species: Implications for Clostridium difficile Recurrence  

PubMed Central

We determined the comparative activity of SMT19969 (SMT) against 162 strains representing 35 well-characterized Clostridium species in clusters I to XIX and 13 Clostridium species that had no 16S rRNA match. SMT MICs ranged from 0.06 to >512 ?g/ml and were not species related. SMT might have less impact on normal gut microbiota than other Clostridium difficile infection (CDI) antimicrobials. PMID:24247123

Citron, Diane M.; Tyrrell, Kerin L.

2014-01-01

355

Precipitation of cadmium by Clostridium thermoaceticum.  

PubMed Central

Cadmium at an initial concentration of 1 mM was completely precipitated by cultures of Clostridium thermoaceticum in complex medium. The precipitation was energy dependent and required cysteine, although cysteine alone did not act as a growth substrate. Electron microscopic analysis revealed localized areas of precipitation at the surfaces of nonstarved cells as well as precipitate in the surrounding medium. The addition of cadmium had no apparent effect on growth or acetogenesis. However, nickel and cadmium were synergistically toxic at a concentration (1 mM) at which neither alone was toxic. The amount of protein extracted from cadmium-treated cultures was twofold higher than that in control extracts, and the amount of total sulfide was fourfold higher in cultures containing cadmium than in control cultures. Comparable levels of cysteine desulfhydrase activity were observed in extracts of both cadmium-treated and control cultures, but the enzyme activity was expressed maximally about 24 h earlier in the cadmium-treated cultures than in the untreated controls. Images PMID:8439169

Cunningham, D P; Lundie, L L

1993-01-01

356

Diagnosis and Management of Clostridium difficile Infection.  

PubMed

There have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease, attributed to the emergence of a fluoroquinolone-resistant "hypervirulent" strain, ribotype 027. C. difficile is now the most common pathogen causing hospital-acquired infection in U.S. hospitals, and community-acquired infections are increasing. The diagnosis of CDI is based on a combination of signs and symptoms, confirmed by laboratory tests. Clinical manifestations of CDI can range from asymptomatic colonization to severe pseudomembranous colitis and death. Many aspects of laboratory diagnosis of CDI remain contentious. Toxin enzyme immunoassays are too insensitive to be used alone, while nucleic acid amplification tests have emerged as an option, either as a stand-alone test or as part of a multitest algorithm. Oral vancomycin and metronidazole have been the recommended antimicrobial therapy options, and fidaxomicin is an effective new alternative. There is ongoing concern regarding the potential inferiority of metronidazole, in particular for severe CDI. Management of severe CDI and recurrent CDI continue to represent major treatment challenges. Biological therapies for the restoration of the intestinal microbiota (e.g., fecal microbiota transplantation) and monoclonal antibody therapy are promising approaches for CDI management, in particular troublesome recurrent CDI. This review will concentrate on the diagnosis and management of CDI in adults. PMID:25643269

Korman, Tony M

2015-02-01

357

The Changing Epidemiology of Clostridium difficile Infections  

PubMed Central

Summary: The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents. PMID:20610822

Freeman, J.; Bauer, M. P.; Baines, S. D.; Corver, J.; Fawley, W. N.; Goorhuis, B.; Kuijper, E. J.; Wilcox, M. H.

2010-01-01

358

Motility and Flagellar Glycosylation in Clostridium difficile? †  

PubMed Central

In this study, intact flagellin proteins were purified from strains of Clostridium difficile and analyzed using quadrupole time of flight and linear ion trap mass spectrometers. Top-down studies showed the flagellin proteins to have a mass greater than that predicted from the corresponding gene sequence. These top-down studies revealed marker ions characteristic of glycan modifications. Additionally, diversity in the observed masses of glycan modifications was seen between strains. Electron transfer dissociation mass spectrometry was used to demonstrate that the glycan was attached to the flagellin protein backbone in O linkage via a HexNAc residue in all strains examined. Bioinformatic analysis of C. difficile genomes revealed diversity with respect to glycan biosynthesis gene content within the flagellar biosynthesis locus, likely reflected by the observed flagellar glycan diversity. In C. difficile strain 630, insertional inactivation of a glycosyltransferase gene (CD0240) present in all sequenced genomes resulted in an inability to produce flagellar filaments at the cell surface and only minor amounts of unmodified flagellin protein. PMID:19749038

Twine, Susan M.; Reid, Christopher W.; Aubry, Annie; McMullin, David R.; Fulton, Kelly M.; Austin, John; Logan, Susan M.

2009-01-01

359

Clostridium septicum sepsis and its implications.  

PubMed

An elderly gentleman, who had 12 years earlier been successfully treated for colon cancer, presented with fever, rigours, right upper quadrant abdominal pain and tenderness. A CT of the abdomen revealed a colonic mass distal to the hepatic flexure with multiple gas locules and a walled off perforation. He underwent a right hemicolectomy. Histology confirmed multifocal colonic adenocarcinoma. His admission blood cultures grew Clostridium septicum. A week postoperatively he developed intermittent fevers and abdominal pain. Repeat CT revealed an abdominal collection adjacent to the new anastomosis, but more importantly, a sharply shouldered aneurysmal dilation of the infra-renal abdominal aorta. These findings prompted immediate surgical drainage of the collection, repair of the anastomostic leak, resection of the infected aortic aneurysm and replacement with a tube graft. This case highlights the clinical significance of C septicum bacteraemia: its association with occult colonic malignancy and with mycotic aneurysm formation. Clostridia isolated from blood cultures should not be dismissed as contaminants but fully identified to ensure appropriate patient management. PMID:22962388

Khalid, Muhammad; Lazarus, Rajeka; Bowler, Ian C J W; Darby, Chris

2012-01-01

360

Crucial role of phospholipase C epsilon in skin inflammation induced by tumor-promoting phorbol ester.  

PubMed

In two-stage skin chemical carcinogenesis, phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) acts as a promoter essential for clonal expansion of the initiated cells carrying the activated ras oncogenes. Although protein kinase C (PKC) isozymes are the main targets of TPA, their role in tumor promotion remains controversial. We previously reported that mice lacking a Ras/Rap effector phospholipase C epsilon (PLC epsilon(-/-) mice) exhibited marked resistance to tumor formation in the two-stage skin carcinogenesis. PLC epsilon(-/-) mice also failed to exhibit basal layer cell proliferation and epidermal hyperplasia induced by TPA, suggesting a role of PLC epsilon in tumor promotion. Here, we show that PLC epsilon(-/-) mice exhibit resistance to TPA-induced skin inflammation as assessed by reduction in edema, granulocyte infiltration, and expression of a proinflammatory cytokine, interleukin-1 alpha (IL-1 alpha). On the other hand, the proliferative potentials of keratinocytes or dermal fibroblasts in culture remain unaffected by the PLC epsilon background, suggesting that the PLC epsilon's role in tumor promotion may be ascribed to augmentation of inflammatory responses. In dermal fibroblast primary culture, TPA can induce activation of the PLC epsilon lipase activity, which leads to the induction of IL-1 alpha expression. Experiments using small interfering RNA-mediated knockdown indicate that this activation is mediated by Rap1, which is activated by a TPA-responsive guanine nucleotide exchange factor RasGRP3. Moreover, TPA-induced activation of Rap1 and PLC epsilon is inhibited by a PKC inhibitor GF109203X, indicating a crucial role of PKC in signaling from TPA to PLC epsilon. These results imply that two TPA targets, RasGRP3 and PKC, are involved in TPA-induced inflammation through PLC epsilon activation, leading to tumor promotion. PMID:18172297

Ikuta, Shuzo; Edamatsu, Hironori; Li, Mingzhen; Hu, Lizhi; Kataoka, Tohru

2008-01-01

361

Comparative In Vitro Activities of SMT19969, a New Antimicrobial Agent, against Clostridium difficile and 350 Gram-Positive and Gram-Negative Aerobic and Anaerobic Intestinal Flora Isolates  

PubMed Central

The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active against C. difficile isolates (MIC range, 0.125 to 0.5 ?g/ml; MIC90, 0.25 ?g/ml), including ribotype 027 strains, than fidaxomicin (range, 0.06 to 1 ?g/ml; MIC90, 0.5 ?g/ml) and two to six dilutions lower than either vancomycin or metronidazole. SMT19969 and fidaxomicin were generally less active against Gram-negative anaerobes, especially the Bacteroides fragilis group species, than vancomycin and metronidazole, suggesting that SMT19969 has a lesser impact on the normal intestinal microbiota that maintain colonization resistance. SMT19969 showed limited activity against other Gram-positive anaerobes, including Bifidobacteria species, Eggerthella lenta, Finegoldia magna, and Peptostreptococcus anaerobius, with MIC90s of >512, >512, 64, and 64 ?g/ml, respectively. Clostridium species showed various levels of susceptibility, with C. innocuum being susceptible (MIC90, 1 ?g/ml) and C. ramosum and C. perfringens being nonsusceptible (MIC90, >512 ?g/ml). Activity against Lactobacillus spp. (range, 0.06 to >512 ?g/ml; MIC90, >512 ?g/ml) was comparable to that of fidaxomicin and varied by species and strain. Gram-positive aerobic cocci (Staphylococcus aureus, Enterococcus faecalis, E. faecium, and streptococci) showed high SMT19969 MIC90 values (128 to >512 ?g/ml). PMID:23877700

Citron, Diane M.; Tyrrell, Kerin L.; Merriam, C. Vreni

2013-01-01

362

Improved solution for system identification equations by Epsilon-Decomposition  

NASA Technical Reports Server (NTRS)

Matrix eigenvalue theory is used to examine the source of ill-conditioning in linear algebraic equations. This approach highlights the crucial role played by the zero and near-zero eigenvalues and corresponding eigenvectors of poorly conditioned systems. Insight gained from this approach is used to significantly improve a recently developed solution procedure called Epsilon-Decomposition (E-D). E-D is an efficient alternative to Singular Value Decomposition (SVD) for ill-conditioned systems arising in parameter estimation and system identification studies. The efficiency of the improved E-D over SVD resides in the need to only obtain the zero and near-zero eigenvalues of the coefficient matrix as opposed to all of its eigenvalues and vectors (as required by SVD). Thus, the efficiency of E-D is significant for large matrices with small rank deficiency.

Ojalvo, Irving U.

1990-01-01

363

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

364

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

365

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

366

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{percent} by weight epsilon phase 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW) and 4.8{percent} 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{percent} HMX and 4.5{percent} 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 flow model for LX-19 was developed which differed from those for HMX-inert binder formulations only by a 25{percent} higher hot spot growth rate. {copyright} {ital 1996 American Institute of Physics.}

Tarver, C.M.; Simpson, R.L.; Urtiew, P.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-282, Livermore, California 94551 (United States)

1996-05-01

367

Data Evaluation for 56Co epsilon + beta+ Decay  

SciTech Connect

Recommended values for nuclear and atomic data pertaining to the {var_epsilon} + {beta}{sup +} decay of {sup 56}Co are provided here, followed by comments on evaluation procedures and a summary of all available experimental data. {sup 56}Co is a radionuclide which is potentially very useful for Ge detector efficiency calibration because it is readily produced via the {sup 56}Fe(p,n) reaction, its half-life of 77.24 days is conveniently long, and it provides a number of relatively strong {gamma} rays with energies up to {approx}3500 keV. The transition intensities recommended here for the strongest lines will be included in the forthcoming International Atomic Energy Agency Coordinated Research Programme document ''Update of X- and Gamma-ray Decay Data Standards for Detector Calibration and Other Applications'', and the analysis for all transitions along with relevant atomic data have been provided to the Decay Data Evaluation Project.

Baglin, Coral M.; MacMahon, T. Desmond

2005-02-28

368

A spectroscopic investigation of the eclipsing binary Epsilon Aurigae  

NASA Technical Reports Server (NTRS)

The objectives were to examine, in detail, the spectra of the eclipsing binary Epsilon Aurigae taken with the IUE satellite telescope during the 1982 to 1984 eclipse. All of the low resolution spectra were analyzed and UV light curves are presented. The primary findings are as follows: (1) a constant eclipse depth from 1600 A to longer wavelengths and a sharp drop in the eclipse depth from 1600 to 1200 A; (2) the absence of large amplitude fluctuations in the UV as expected from a Cepheid primary; and (3) equal ingress and egress times in contradiction to that interpreted from visible light curves. The effects of these findings on the eclipse geometry are being studied.

Balachandran, Suchitra

1991-01-01

369

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

370

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

371

Constraints from Asymmetric Heating: Investigating the Epsilon Aurigae Disk  

NASA Astrophysics Data System (ADS)

Epsilon Aurigae is a long-period eclipsing binary that likely contains an F0Ia star and a circumstellar disk enshrouding a hidden companion, assumed to be a main-sequence B star. High uncertainty in its parallax has kept the evolutionary status of the system in question and, hence, the true nature of each component. This unknown, as well as the absence of solid state spectral features in the infrared, requires an investigation of a wide parameter space by means of both analytic and Monte Carlo radiative transfer (MCRT) methods. The first MCRT models of epsilon Aurigae that include all three system components are presented here. We seek additional system parameter constraints by melding analytic approximations with MCRT outputs (e.g., dust temperatures) on a first-order level. The MCRT models investigate the effects of various parameters on the disk-edge temperatures; these include two distances, three particle size distributions, three compositions, and two disk masses, resulting in 36 independent models. Specifically, the MCRT temperatures permit analytic calculations of effective heating and cooling curves along the disk edge. These are used to calculate representative observed fluxes and corresponding temperatures. This novel application of thermal properties provides the basis for utilization of other binary systems containing disks. We find degeneracies in the model fits for the various parameter sets. However, the results show a preference for a carbon disk with particle size distributions >=10 ?m. Additionally, a linear correlation between the MCRT noon and basal temperatures serves as a tool for effectively eliminating portions of the parameter space.

Pearson, Richard L., III; Stencel, Robert E.

2015-01-01

372

The Epsilon Expansion via Hypergeometric Functions and Differential S.A. Yost and M. Kalmykov  

E-print Network

of hypergeometric functions about rational values of the parameters. Outline: · Integration-by-parts (IBPThe Epsilon Expansion via Hypergeometric Functions and Differential Reduction S.A. Yost and M.A. Yost Epsilon Expansion via Hypergeometric Functions and Differential Reduction DPF Meeting, Providence

Yost, Scott

373

GATA1 and YY1 are developmental repressors of the human epsilon-globin gene.  

PubMed Central

The human epsilon-globin gene is transcribed in erythroid cells only during the embryonic stages of development. Expression of epsilon-globin gene, however, can be maintained in adult transgenic mice following removal of DNA positioned between -467 and -182 bp upstream of the epsilon-globin cap site. We have identified three protein binding regions within this silencer; a CCACC motif around -379, two overlapping motifs for YY1 and GATA around -269 and a GATA motif around -208 and we have analyzed their function during development by studying several mutants in transgenic mice. Mutation of the -208 GATA motif allows high epsilon-globin transgene expression in the adult suggesting that, in addition to its positive effects on transcription, GATA-1 also plays a negative role in the regulation of globin gene expression during development. Repression of epsilon gene expression in the adult also requires a functional YY1 binding site at position -269. Finally, mutation of the -379 CCACC site results in a small but detectable level of epsilon expression in adult erythroid cells. Thus, multiple proteins, including GATA-1, participate in the formation of the epsilon gene repressor complex that may disrupt the interaction between the proximal epsilon-promoter and the locus control region (LCR) in definitive erythroid cells. Images PMID:7882983

Raich, N; Clegg, C H; Grofti, J; Roméo, P H; Stamatoyannopoulos, G

1995-01-01

374

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- dopedUltrafast plasmonics using transparent conductive oxide hybrids in the epsilon-near-zero regime plasmonics using transparent conductive oxide hybrids in the epsilon-near-zero regime Daniel Traviss,1 Roman

Zheludev, Nikolay

375

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

376

Asymptomatic Clostridium difficile Colonisation and Onward Transmission  

PubMed Central

Introduction Combined genotyping/whole genome sequencing and epidemiological data suggest that in endemic settings only a minority of Clostridium difficile infection, CDI, is acquired from other cases. Asymptomatic patients are a potential source for many unexplained cases. Methods We prospectively screened a cohort of medical inpatients in a UK teaching hospital for asymptomatic C. difficile carriage using stool culture. Electronic and questionnaire data were used to determine risk factors for asymptomatic carriage by logistic regression. Carriage isolates were compared with all hospital/community CDI cases from the same geographic region, from 12 months before the study to 3 months after, using whole genome sequencing and hospital admission data, assessing particularly for evidence of onward transmission from asymptomatic cases. Results Of 227 participants recruited, 132 provided ?1 stool samples for testing. 18 participants were culture-positive for C. difficile, 14/132(11%) on their first sample. Independent risk factors for asymptomatic carriage were patient reported loose/frequent stool (but not meeting CDI criteria of ?3 unformed stools in 24 hours), previous overnight hospital stay within 6 months, and steroid/immunosuppressant medication in the last 6 months (all p?0.02). Surprisingly antibiotic exposure in the last 6 months was independently associated with decreased risk of carriage (p?=?0.005). The same risk factors were identified excluding participants reporting frequent/loose stool. 13/18(72%) asymptomatically colonised patients carried toxigenic strains from common disease-causing lineages found in cases. Several plausible transmission events to asymptomatic carriers were identified, but in this relatively small study no clear evidence of onward transmission from an asymptomatic case was seen. Conclusions Transmission events from any one asymptomatic carrier are likely to be relatively rare, but as asymptomatic carriage is common, it may still be an important source of CDI, which could be quantified in larger studies. Risk factors established for asymptomatic carriage may help identify patients for inclusion in such studies. PMID:24265690

Eyre, David W.; Griffiths, David; Vaughan, Alison; Golubchik, Tanya; Acharya, Milind; O’Connor, Lily; Crook, Derrick W.

2013-01-01

377

Clinical impact of Clostridium difficile colonization.  

PubMed

Clostridium dif?cile can cause antibiotic-associated diarrhea in hospitalized patients. Asymptomatic colonization by C. difficile is common during the neonatal period and early infancy, ranging from 21% to 48%, and in childhood. The colonization rate of C. difficile in adult hospitalized patients shows geographic variation, ranging from 4.4% to 23.2%. Asymptomatic carriage in neonates caused no further disease in many studies, whereas adult patients colonized with toxigenic C. difficile were prone to the subsequent development of C. difficile-associated diarrhea (CDAD). However, the carriage of nontoxigenic C. difficile strains appears to prevent CDAD in hamsters and humans. Risk factors for C. difficile colonization include recent hospitalization, exposure to antimicrobial agents or gastric acid-suppressing drugs (such as proton-pump inhibitors and H2 blockers), a history of CDAD or cytomegalovirus infection, the presence of an underlying illness, receipt of immunosuppressants, the presence of antibodies against toxin B, and Toll-like receptor 4 polymorphisms. Asymptomatic C. difficile carriers are associated with significant skin and environmental contamination, similar to those with CDAD, and contact isolation and hand-washing practices should therefore be employed as infection control policies for the prevention of C. difficile spread. Treating patients with asymptomatic C. difficile colonization with metronidazole or vancomycin is not suggested by the currently available evidence. In conclusion, asymptomatic C. difficile colonization may lead to skin and environmental contamination by C. difficile, but more attention should be paid to the clinical impact of those with C. difficile colonization. PMID:24890755

Hung, Yuan-Pin; Lee, Jen-Chieh; Lin, Hsiao-Ju; Liu, Hsiao-Chieh; Wu, Yi-Hui; Tsai, Pei-Jane; Ko, Wen-Chien

2014-05-30

378

Characterization of Clostridium thermocellum JW20  

PubMed Central

Clostridium thermocellum JW20 (ATCC 31549), which was isolated from a Louisiana cotton bale, grew on cellulose, cellobiose, and xylooligomers and, after adaptation, on glucose, fructose, and xylose in the pH range of 7.5 to 6.1 with Topt of 60°C, Tmax of 69°C, and Tmin of above 28°C. Doubling times during growth on cellulose and cellobiose were 6.5 and 2.5 h, respectively. The G+C content of the DNA was 40 mol% (chemical analysis). Growth on cellulose as substrate was totally inhibited in the presence of more than 125 mM sodium sulfate, 300 mM sodium chloride, 250 mM potassium chloride, 200 mM calcium chloride, 125 mM magnesium chloride, 40 mM lactate, or 250 mM acetate. The ratio of the fermentation products ethanol to acetate plus H2 decreased when the culture was agitated. Agitation otherwise increased the rate of cellulose degradation in a growing culture but not under nongrowth conditions or with cell-free culture supernatant containing the extracellular cellulase. Shaking lowered the concentration of H2 in the culture broth and thus minimized inhibition by the H2 formed. Externally added H2 caused an increased formation of ethanol during growth on cellulose or cellobiose. However, at an atmospheric pressure as high as 355 kPa (50 lb/in2), H2 did not cause significant growth inhibition beyond an increasing lag phase (up to 24 h). Several criteria to specifically prove the purity of C. thermocellum cultures were suggested. PMID:16347527

Freier, Doris; Mothershed, Cheryle P.; Wiegel, Juergen

1988-01-01

379

Diagnosis and management of Clostridium difficile infection.  

PubMed

Clostridium difficile infection (CDI) is increasing in frequency and severity in and out of the hospital, with a high probability of recurrence after treatment. The recent literature on CDI was reviewed using PubMed to include recent publications dealing with diagnosis and therapy. Real-time polymerase chain reaction is a sensitive and useful diagnostic test for CDI but there are growing concerns of false-positive test results if the rate of CDI is low in the patient population providing samples and/or if the population being studied commonly includes people with C difficile colonization. Recommended therapy of CDI includes oral metronidazole for milder cases of CDI and oral vancomycin or fidaxomicin for more severe cases, each given for 10 days. Colectomy is being performed more frequently in patients with fulminant CDI. For treatment of first recurrences the drug used in the first bout can be used again and for second recurrences longer courses of vancomycin often are given in a tapered dose or intermittently to allow gut flora reconstitution, or other treatments including fidaxomicin may be used. Bacteriotherapy with fecal transplantation is playing an increasing role in therapy of recurrent cases. Metagenomic studies of patients with CDI during successful therapy are needed to determine how best to protect the flora from assaults from antibacterial drugs and to develop optimal therapeutic approaches. Immunotherapy and immunoprophylaxis offer opportunities to prevent CDI, to speed up recovery from CDI, and to eliminate recurrent infection. Humanized monoclonal antitoxin antibodies and active immunization with vaccines against C difficile or its toxins are both in development and appear to be of potential value. PMID:23542332

Dupont, Herbert L

2013-10-01

380

Form and function of Clostridium thermocellum biofilms.  

PubMed

The importance of bacterial adherence has been acknowledged in microbial lignocellulose conversion studies; however, few reports have described the function and structure of biofilms supported by cellulosic substrates. We investigated the organization, dynamic formation, and carbon flow associated with biofilms of the obligately anaerobic cellulolytic bacterium Clostridium thermocellum 27405. Using noninvasive, in situ fluorescence imaging, we showed biofilms capable of near complete substrate conversion with a characteristic monolayered cell structure without an extracellular polymeric matrix typically seen in biofilms. Cell division at the interface and terminal endospores appeared throughout all stages of biofilm growth. Using continuous-flow reactors with a rate of dilution (2 h(-1)) 12-fold higher than the bacterium's maximum growth rate, we compared biofilm activity under low (44 g/liter) and high (202 g/liter) initial cellulose loading. The average hydrolysis rate was over 3-fold higher in the latter case, while the proportions of oligomeric cellulose hydrolysis products lost from the biofilm were 13.7% and 29.1% of the total substrate carbon hydrolyzed, respectively. Fermentative catabolism was comparable between the two cellulose loadings, with ca. 4% of metabolized sugar carbon being utilized for cell production, while 75.4% and 66.7% of the two cellulose loadings, respectively, were converted to primary carbon metabolites (ethanol, acetic acid, lactic acid, carbon dioxide). However, there was a notable difference in the ethanol-to-acetic acid ratio (g/g), measured to be 0.91 for the low cellulose loading and 0.41 for the high cellulose loading. The results suggest that substrate availability for cell attachment rather than biofilm colonization rates govern the efficiency of cellulose conversion. PMID:23087042

Dumitrache, Alexandru; Wolfaardt, Gideon; Allen, Grant; Liss, Steven N; Lynd, Lee R

2013-01-01

381

Form and Function of Clostridium thermocellum Biofilms  

PubMed Central

The importance of bacterial adherence has been acknowledged in microbial lignocellulose conversion studies; however, few reports have described the function and structure of biofilms supported by cellulosic substrates. We investigated the organization, dynamic formation, and carbon flow associated with biofilms of the obligately anaerobic cellulolytic bacterium Clostridium thermocellum 27405. Using noninvasive, in situ fluorescence imaging, we showed biofilms capable of near complete substrate conversion with a characteristic monolayered cell structure without an extracellular polymeric matrix typically seen in biofilms. Cell division at the interface and terminal endospores appeared throughout all stages of biofilm growth. Using continuous-flow reactors with a rate of dilution (2 h?1) 12-fold higher than the bacterium's maximum growth rate, we compared biofilm activity under low (44 g/liter) and high (202 g/liter) initial cellulose loading. The average hydrolysis rate was over 3-fold higher in the latter case, while the proportions of oligomeric cellulose hydrolysis products lost from the biofilm were 13.7% and 29.1% of the total substrate carbon hydrolyzed, respectively. Fermentative catabolism was comparable between the two cellulose loadings, with ca. 4% of metabolized sugar carbon being utilized for cell production, while 75.4% and 66.7% of the two cellulose loadings, respectively, were converted to primary carbon metabolites (ethanol, acetic acid, lactic acid, carbon dioxide). However, there was a notable difference in the ethanol-to-acetic acid ratio (g/g), measured to be 0.91 for the low cellulose loading and 0.41 for the high cellulose loading. The results suggest that substrate availability for cell attachment rather than biofilm colonization rates govern the efficiency of cellulose conversion. PMID:23087042

Dumitrache, Alexandru; Allen, Grant; Liss, Steven N.; Lynd, Lee R.

2013-01-01

382

Characterization of CRISPR RNA processing in Clostridium thermocellum and Methanococcus  

E-print Network

Characterization of CRISPR RNA processing in Clostridium thermocellum and Methanococcus maripaludis The CRISPR arrays found in many bacteria and most archaea are transcribed into a long precursor RNA that is processed into small clustered regularly interspaced short palindromic repeats (CRISPR) RNAs (cr

Will, Sebastian

383

Closed Genome Sequence of Clostridium pasteurianum ATCC 6013  

PubMed Central

We report here the closed genome of Clostridium pasteurianum ATCC 6013, a saccharolytic, nitrogen-fixing, and spore-forming Gram-positive obligate anaerobe. The organism is of biotechnological interest due to the production of solvents (butanol and 1,3-propanediol) but can be associated with food spoilage. The genome comprises a total of 4,351,223 bp.

Rotta, Carlo; Poehlein, Anja; Schwarz, Katrin; McClure, Peter; Daniel, Rolf

2015-01-01

384

Seasonality of Clostridium difficile infections in Southern Germany  

PubMed Central

SUMMARY Between 2000 and 2009, the total number of patients with Clostridium difficile infections increased considerably in Southeastern Germany. A clear seasonality was observed with a higher number of affected patients occurring in the winter months (January–March). Moxifloxacin and erythromycin-resistant C. difficile PCR ribotypes 001 (72%) and 027 (4·6%) were the most commonly isolated strains. PMID:22152928

REIL, M.; HENSGENS, M. P. M.; KUIJPER, E. J.; JAKOBIAK, T.; GRUBER, H.; KIST, M.; BORGMANN, S.

2012-01-01

385

Seasonality of Clostridium difficile infections in Southern Germany.  

PubMed

Between 2000 and 2009, the total number of patients with Clostridium difficile infections increased considerably in Southeastern Germany. A clear seasonality was observed with a higher number of affected patients occurring in the winter months (January-March). Moxifloxacin and erythromycin-resistant C. difficile PCR ribotypes 001 (72%) and 027 (4·6%) were the most commonly isolated strains. PMID:22152928

Reil, M; Hensgens, M P M; Kuijper, E J; Jakobiak, T; Gruber, H; Kist, M; Borgmann, S

2012-10-01

386

Rifampin and Rifaximin Resistance in Clinical Isolates of Clostridium difficile  

Microsoft Academic Search

Rifaximin, a poorly absorbed rifamycin derivative, is a promising alternative for the treatment of Clostridium difficile infections. Resistance to this agent has been reported, but no commercial test for rifaximin resistance exists and the molecular basis of this resistance has not been previously studied in C. difficile. To evaluate whether the rifampin Etest would be a suitable substitute for rifaximin

Jennifer R. O'Connor; Minerva A. Galang; Susan P. Sambol; David W. Hecht; Gayatri Vedantam; Dale N. Gerding; Stuart Johnson

2008-01-01

387

Emergence of Clostridium tertium as a pathogen in neutropenic patients.  

PubMed

Although usually considered a non-pathogen, Clostridium tertium was isolated from 10 immunosuppressed patients including seven patients with bacteremia. This organism can grow aerobically and can be easily disregarded as a contaminant. It also has a somewhat unusual susceptibility pattern, with significant resistance to the penicillins, cephalosporins, and clindamycin, possibly explaining its emergence in immunocompromised patients already receiving multiple antibiotics. PMID:3766589

Thaler, M; Gill, V; Pizzo, P A

1986-10-01

388

Clostridium hathewayi bacteraemia and surgical site infection after uterine myomectomy.  

PubMed

A 42-year-old woman with uterine fibroids underwent myomectomy. She developed postoperative sepsis and bloodstream infection with Clostridium hathewayi secondary to an infected haematoma. The patient was readmitted after failure of oral antibiotic therapy and underwent intrauterine drainage followed by prolonged parenteral antibiotic therapy. The patient was followed for 1 year and did not have any relapse of infection. PMID:24596408

Dababneh, Ala S; Nagpal, Avish; Palraj, Bharath Raj Varatharaj; Sohail, M Rizwan

2014-01-01

389

Clostridium septicum brain abscesses in a premature neonate.  

PubMed

Brain abscesses in neonates are typically caused by Gram-negative organisms. There are no previously described cases caused by Clostridium septicum. We present a case of a premature male infant who developed recurrent episodes of suspected necrotizing enterocolitis followed by brain abscesses, cerebritis and ventriculitis caused by C. septicum. PMID:24220230

Sadarangani, Sapna P; Batdorf, Rachel; Buchhalter, Lillian C; Mrelashvili, Anna; Banerjee, Ritu; Henry, Nancy K; Huskins, W Charles; Boyce, Thomas G

2014-05-01

390

Quantification of Clostridium difficile in Antibiotic-Associated-Diarrhea Patients?  

PubMed Central

Comparing culture- and non-culture-based methods for quantifying Clostridium difficile in antibiotic-associated-diarrhea patients, we found that the real-time PCR method correlated well with quantitative culture and was more sensitive. A positive association between the population levels of C. difficile and the presence of its toxins was found. PMID:21865427

Naaber, Paul; Štšepetova, Jelena; Smidt, Imbi; Rätsep, Merle; Kõljalg, Siiri; Lõivukene, Krista; Jaanimäe, Liis; Löhr, Iren H.; Natås, Olav B.; Truusalu, Kai; Sepp, Epp

2011-01-01

391

BUTANOL PRODUCTION FROM WHEAT STRAW HYDROLYSATE USING CLOSTRIDIUM BEIJERINCKII  

Technology Transfer Automated Retrieval System (TEKTRAN)

In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures using Clostridium beijerinckii P260. In control fermentation, 48.9 gL**-1 glucose was used to produce 20.1 gL**-1 ABE with a productivity and yield of 0.28 gL**-1h**-1 and 0....

392

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 104000, Czech Republic The anaerobic fungi were reported as the most effective cellulose degrading microorganisms in the rumen (Wilson and Wood, 1992, Enzyme Microb Technol, 14, 258-264). Similarly to other fungi

Paris-Sud XI, Université de

393

Inhibition of the cytotoxic effect of Clostridium difficile in vitro by Clostridium butyricum MIYAIRI 588 strain.  

PubMed

In contrast to most modern pharmaceuticals, probiotics are used in many parts of the world with little or no research data on the complex system of interactions that each strain may elicit in the human body. Research on probiotics has recently become more significant, as probiotics have begun to be prescribed by clinicians as an alternative for some gut infections, especially when antibiotics are contraindicated. This study attempted to elucidate the inhibitory interaction between the Japanese probiotic strain Clostridium butyricum MIYAIRI 588 (CBM588) and the hospital pathogen Clostridium difficile, which is responsible for a large proportion of antibiotic-associated diarrhoea and colitis. CBM588 has previously shown effectiveness against C. difficile in vivo, and here it was found that the toxicity of C. difficile in in vitro co-culture with CBM588 was greatly decreased or absent. This was dependent on the inoculation ratio and was not accounted for by the small degree of growth and mRNA inhibition observed. CBM588 and its cell-free supernatant also had no effect on toxin already secreted into the culture medium, and culture of the two strains separated by a semi-permeable membrane resulted in loss of the inhibition. Therefore, it was concluded that the detoxification probably occurred by the inhibition of toxin protein production and that this required close proximity or contact between the two species. The low-pH conditions caused by organic acid secretion were also observed to have inhibitory effects on C. difficile growth, metabolism and toxicity. PMID:21700738

Woo, Timothy D H; Oka, Kentaro; Takahashi, Motomichi; Hojo, Fuhito; Osaki, Takako; Hanawa, Tomoko; Kurata, Satoshi; Yonezawa, Hideo; Kamiya, Shigeru

2011-11-01

394

Development of a real time PCR Taqman assay based on the TPI gene for simultaneous identification of Clostridium chauvoei and Clostridium septicum.  

PubMed

In the present study, a Taqman allelic discrimination assay based on three SNPs of the TPI gene is described. It was used as a differential diagnostic tool to detect blackleg and malignant edema. Sudden deaths of grazing ruminants, such as cattle, sheep and goats, which show clinical signs related to hyperacute infective processes, encouraged the development of a rapid and precise diagnostic molecular method. Specific primers and probes for Clostridium septicum and Clostridium chauvoei were designed on the basis of the TPI gene sequence. The multiplex PCR was tested on the DNA of a total of 57 strains, including 24 Clostridium chauvoei, 20 Clostridium septicum, 1 Bacillus anthracis and 12 other Clostridium spp. The DNA samples from Clostridium chauvoei and Clostridium septicum strains were amplified. Amplification of other DNA samples was not observed, with the exception of Clostridium tertium, which showed a weak positive signal. To avoid misdiagnosis, a confirmatory assay based on a Sybr green real time PCR was proposed. The authors confirmed the efficacy and the specificity of the test used in this study, which proved to be a useful tool for the diagnosis of clostridiosis that are often diagnosed using only traditional tools. PMID:21182874

Garofolo, G; Galante, D; Serrecchia, L; Buonavoglia, D; Fasanella, A

2011-02-01

395

Characterisation of non-toxigenic Clostridium spp. strains, to use as surrogates for non-proteolytic Clostridium botulinum in chilled food challenge testing.  

PubMed

Under many of the conditions studied, a two-strain cocktail of non-toxigenic Clostridium spp. was found to be suitable as a surrogate for non-proteolytic Clostridium botulinum, and has the potential for use in chilled food challenge tests measuring growth. Non-toxigenic surrogates could also be used in thermal process screening studies. PMID:25433276

Parker, M D; Barrett, P I; Shepherd, J; Price, L J; Bull, S D

2015-01-01

396

Resolution of Culture Clostridium bifermentans DPH-1 into Two Populations, a Clostridium sp. and Tetrachloroethene-Dechlorinating Desulfitobacterium hafniense Strain JH1?  

PubMed Central

Clostridium bifermentans strain DPH-1 reportedly dechlorinates tetrachloroethene (PCE) to cis-1,2-dichloroethene. Cultivation-based approaches resolved the DPH-1 culture into two populations: a nondechlorinating Clostridium sp. and PCE-dechlorinating Desulfitobacterium hafniense strain JH1. Strain JH1 carries pceA, encoding a PCE reductive dehalogenase, and shares other characteristics with Desulfitobacterium hafniense strain Y51. PMID:18708512

Fletcher, Kelly E.; Ritalahti, Kirsti M.; Pennell, Kurt D.; Takamizawa, Kazuhiro; Löffler, Frank E.

2008-01-01

397

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

398

Rcan1 negatively regulates Fc epsilonRI-mediated signaling and mast cell function.  

PubMed

Aggregation of the high affinity IgE receptor (Fc epsilonRI) activates a cascade of signaling events leading to mast cell activation. Subsequently, inhibitory signals are engaged for turning off activating signals. We identified that regulator of calcineurin (Rcan) 1 serves as a negative regulator for turning off Fc epsilonRI-mediated mast cell activation. Fc epsilonRI-induced Rcan1 expression was identified by suppression subtractive hybridization and verified by real-time quantitative polymerase chain reaction and Western blotting. Deficiency of Rcan1 led to increased calcineurin activity, increased nuclear factor of activated T cells and nuclear factor kappaB activation, increased cytokine production, and enhanced immunoglobulin E-mediated late-phase cutaneous reactions. Forced expression of Rcan1 in wild-type or Rcan1-deficient mast cells reduced Fc epsilonRI-mediated cytokine production. Rcan1 deficiency also led to increased Fc epsilonRI-mediated mast cell degranulation and enhanced passive cutaneous anaphylaxis. Analysis of the Rcan1 promoter identified a functional Egr1 binding site. Biochemical and genetic evidence suggested that Egr1 controls Rcan1 expression. Our results identified Rcan1 as a novel inhibitory signal in Fc epsilonRI-induced mast cell activation and established a new link of Egr1 and Rcan1 in Fc epsilonRI signaling. PMID:19124655

Yang, Yong Jun; Chen, Wei; Edgar, Alexander; Li, Bo; Molkentin, Jeffery D; Berman, Jason N; Lin, Tong-Jun

2009-01-16

399

Clostridium difficile 027 infection in Central Italy  

PubMed Central

Background Clostridium difficile (CD) has increasingly become recognised as a significant international health burden, often associated with the healthcare environment. The upsurge in incidence of CD coincided with the emergence of a hypervirulent strain of CD characterized as 027. In 2010, 8 cases of CD 027 infections were identified in Italy. Since then, no further reports have been published. We describe 10 new cases of CD 027 infection occurring in Italy. Methods Since December 2010, stool samples of patients with severe diarrhea and clinical suspicion of the presence of a hypervirulent strain, were tested for CD 027 by the Xpert C. difficile PCR assay (Cepheid, Sunnyvale, CA). Clinical, epidemiological and laboratory data were collected. Results From December 2010 to April 2012, 24 faecal samples from 19 patients who fit the above criteria were submitted to our laboratory. Samples were collected from 7 different hospitals. Of these, 17 had a positive PCR for CD and 10 were the epidemic 027 strain (59%). All PCR positive samples had a positive EIA toxin A/B test. Nine of 10 patients were recently exposed to antimicrobials and were healthcare-associated, including 4 with a history of long term care facility (LTCF) admission; the remaining case was community-associated, namely the wife of a patient with hospital-acquired CD 027 infection. Five patients experienced at least one recurrence of CD associated diarrhea (CDAD) with a total of 12 relapsing episodes. Of these, two patients had 5 and 6 relapses respectively. We compared the 10 patients with 027 CDAD versus the 7 patients with non-027 CDAD. None of the 7 patients with non-027 CDAD had a recent history of LTCF admission and no subsequent relapses were observed (p?=?0.04). Conclusions Our study shows that CD 027 is emerging in healthcare facilities in Italy. Whilst nosocomial acquisition accounted for the majority of such cases, 4 patients had history of a recent stay in a LTCF. We highlight the substantial risks of this highly transmissible organism in such environments. Moreover, 50% of our patients with CDAD from the 027 strain had high relapse rates which may serve to further establish this strain within the Italian health and social care systems. PMID:23259814

2012-01-01

400

Clostridium difficile associated infection, diarrhea and colitis  

PubMed Central

A new, hypervirulent strain of Clostridium difficile, called NAP1/BI/027, has been implicated in C. difficile outbreaks associated with increased morbidity and mortality since the early 2000s. The epidemic strain is resistant to fluoroquinolones in vitro, which was infrequent prior to 2001. The name of this strain reflects its characteristics, demonstrated by different typing methods: pulsed-field gel electrophoresis (NAP1), restriction endonuclease analysis (BI) and polymerase chain reaction (027). In 2004 and 2005, the US Centers for Disease Control and Prevention (CDC) emphasized that the risk of C. difficile-associated diarrhea (CDAD) is increased, not only by the usual factors, including antibiotic exposure, but also gastrointestinal surgery/manipulation, prolonged length of stay in a healthcare setting, serious underlying illness, immune-compromising conditions, and aging. Patients on proton pump inhibitors (PPIs) have an elevated risk, as do peripartum women and heart transplant recipients. Before 2002, toxic megacolon in C. difficile-associated colitis (CDAC), was rare, but its incidence has increased dramatically. Up to two-thirds of hospitalized patients may be infected with C. difficile. Asymptomatic carriers admitted to healthcare facilities can transmit the organism to other susceptible patients, thereby becoming vectors. Fulminant colitis is reported more frequently during outbreaks of C. difficile infection in patients with inflammatory bowel disease (IBD). C. difficile infection with IBD carries a higher mortality than without underlying IBD. This article reviews the latest information on C. difficile infection, including presentation, vulnerable hosts and choice of antibiotics, alternative therapies, and probiotics and immunotherapy. We review contact precautions for patients with known or suspected C. difficile-associated disease. Healthcare institutions require accurate and rapid diagnosis for early detection of possible outbreaks, to initiate specific therapy and implement effective control measures. A comprehensive C. difficile infection control management rapid response team (RRT) is recommended for each health care facility. A communication network between RRTs is recommended, in coordination with each country’s department of health. Our aim is to convey a comprehensive source of information and to guide healthcare professionals in the difficult decisions that they face when caring for these oftentimes very ill patients. PMID:19340897

Hookman, Perry; Barkin, Jamie S

2009-01-01

401

Aerial Dissemination of Clostridium difficile spores  

PubMed Central

Background Clostridium difficile-associated diarrhoea (CDAD) is a frequently occurring healthcare-associated infection, which is responsible for significant morbidity and mortality amongst elderly patients in healthcare facilities. Environmental contamination is known to play an important contributory role in the spread of CDAD and it is suspected that contamination might be occurring as a result of aerial dissemination of C. difficile spores. However previous studies have failed to isolate C. difficile from air in hospitals. In an attempt to clarify this issue we undertook a short controlled pilot study in an elderly care ward with the aim of culturing C. difficile from the air. Methods In a survey undertaken during February (two days) 2006 and March (two days) 2007, air samples were collected using a portable cyclone sampler and surface samples collected using contact plates in a UK hospital. Sampling took place in a six bedded elderly care bay (Study) during February 2006 and in March 2007 both the study bay and a four bedded orthopaedic bay (Control). Particulate material from the air was collected in Ringer's solution, alcohol shocked and plated out in triplicate onto Brazier's CCEY agar without egg yolk, but supplemented with 5 mg/L of lysozyme. After incubation, the identity of isolates was confirmed by standard techniques. Ribotyping and REP-PCR fingerprinting were used to further characterise isolates. Results On both days in February 2006, C. difficile was cultured from the air with 23 samples yielding the bacterium (mean counts 53 – 426 cfu/m3 of air). One representative isolate from each of these was characterized further. Of the 23 isolates, 22 were ribotype 001 and were indistinguishable on REP-PCR typing. C. difficile was not cultured from the air or surfaces of either hospital bay during the two days in March 2007. Conclusion This pilot study produced clear evidence of sporadic aerial dissemination of spores of a clone of C. difficile, a finding which may help to explain why CDAD is so persistent within hospitals and difficult to eradicate. Although preliminary, the findings reinforce concerns that current C. difficile control measures may be inadequate and suggest that improved ward ventilation may help to reduce the spread of CDAD in healthcare facilities. PMID:18218089

Roberts, Katherine; Smith, Caroline F; Snelling, Anna M; Kerr, Kevin G; Banfield, Kathleen R; Sleigh, P Andrew; Beggs, Clive B

2008-01-01

402

Mapping the effect of APOE epsilon4 on gray matter loss in Alzheimer's disease in vivo.  

PubMed

Previous studies suggest that in Alzheimer's disease (AD) the Apolipoprotein E (APOE) epsilon4 allele is associated with greater vulnerability of medial temporal lobe structures. However, less is known about its effect on the whole cortical mantle. Here we aimed to identify APOE-related patterns of cortical atrophy in AD using an advanced computational anatomy technique. We studied 15 AD patients carriers (epsilon4+, age: 72+/-10 SD years, MMSE: 20+/-3 SD) and 14 non-carriers (epsilon4-, age: 69+/-9, MMSE: 20+/-5) of the epsilon4 allele and compared them to 29 age-and-sex matched controls (age: 70+/-9, MMSE: 28+/-1). Each subject underwent a clinical evaluation, a neuropsychological battery, and high-resolution MRI. UCLA's cortical pattern matching technique was used to identify regions of local cortical atrophy. epsilon4+ and epsilon4- patients showed similar performance on neuropsychological tests (p>.05, t-test). Diffuse cortical atrophy was detected for both epsilon4+ (p=.0001, permutation test) and epsilon4- patients (p=.0001, permutation test) relative to controls, and overall gray matter loss was about 15% in each patients group. Differences in gray matter loss between carriers and non-carriers mapped to the temporal cortex and right occipital pole (20% greater loss in carriers) and to the posterior cingulate, left orbitofrontal and dorsal fronto-parietal cortex (5-15% greater loss in non-carriers). APOE effect in AD was not significant (p>.74, ANOVA), but a significant APOE by region (temporal vs fronto-parietal cortex) interaction was detected (p=.002, ANOVA), in both early and late-onset patients (p<.05, ANOVA). We conclude that the epsilon4 allele modulates disease phenotype in AD, being associated with a pattern of differential temporal and fronto-parietal vulnerability. PMID:19349226

Pievani, M; Rasser, P E; Galluzzi, S; Benussi, L; Ghidoni, R; Sabattoli, F; Bonetti, M; Binetti, G; Thompson, P M; Frisoni, G B

2009-05-01

403

Production of epsilon-poly-L-lysine by newly isolated Kitasatospora sp. PL6-3.  

PubMed

A novel epsilon-poly-L-lysine (epsilon-PL)-producing strain PL6-3 was isolated from soil, and was identified as a strain of Kitasatospora sp. This is the first detailed report of production of epsilon-PL by a strain in the genera of Kitasatospora. By controlling the culture pH at 4.0, the yield of epsilon-PL from PL6-3 reached 13.9 g/L after 120 h of cultivation in fed-batch fermentation. The morphological characteristics of Kitasatospora sp. PL6-3 in culture broth were different from those reported from strains of Streptomycetaceae, as no mycelium pellets were observed during the course of fermentation of PL6-3, which was beneficial to the assimilation of nutrition and secretion of the products. Furthermore, the molecular mass of the purified epsilon-PL from PL6-3 was determined to be 5.01 kDa by SDS-PAGE and 5.05 kDa by gel permeation chromatography, indicating that the epsilon-PL produced by this strain might be composed of 40 lysine residues. Usually, epsilon-PL with more lysine residues showed higher antimicrobial activity; however, it was difficult to obtain epsilon-PL with more than 36 lysine residues in this study. As a result, epsilon-PL from Kitasatospora sp. PL6-3, which contains more lysine residues than that from other strains, is more promising in the field of food preservatives. PMID:17161019

Ouyang, Jia; Xu, Hong; Li, Sha; Zhu, Hongyang; Chen, Weiwei; Zhou, Jun; Wu, Qun; Xu, Lin; Ouyang, Pingkai

2006-12-01

404

Selective inhibition of casein kinase 1 epsilon minimally alters circadian clock period.  

PubMed

The circadian clock links our daily cycles of sleep and activity to the external environment. Deregulation of the clock is implicated in a number of human disorders, including depression, seasonal affective disorder, and metabolic disorders. Casein kinase 1 epsilon (CK1epsilon) and casein kinase 1 delta (CK1delta) are closely related Ser-Thr protein kinases that serve as key clock regulators as demonstrated by mammalian mutations in each that dramatically alter the circadian period. Therefore, inhibitors of CK1delta/epsilon may have utility in treating circadian disorders. Although we previously demonstrated that a pan-CK1delta/epsilon inhibitor, 4-[3-cyclohexyl-5-(4-fluoro-phenyl)-3H-imidazol-4-yl]-pyrimidin-2-ylamine (PF-670462), causes a significant phase delay in animal models of circadian rhythm, it remains unclear whether one of the kinases has a predominant role in regulating the circadian clock. To test this, we have characterized 3-(3-chloro-phenoxymethyl)-1-(tetrahydro-pyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-ylamine (PF-4800567), a novel and potent inhibitor of CK1epsilon (IC(50) = 32 nM) with greater than 20-fold selectivity over CK1delta. PF-4800567 completely blocks CK1epsilon-mediated PER3 nuclear localization and PER2 degradation. In cycling Rat1 fibroblasts and a mouse model of circadian rhythm, however, PF-4800567 has only a minimal effect on the circadian clock at concentrations substantially over its CK1epsilon IC(50). This is in contrast to the pan-CK1delta/epsilon inhibitor PF-670462 that robustly alters the circadian clock under similar conditions. These data indicate that CK1epsilon is not the predominant mediator of circadian timing relative to CK1delta. PF-4800567 should prove useful in probing unique roles between these two kinases in multiple signaling pathways. PMID:19458106

Walton, Kevin M; Fisher, Katherine; Rubitski, David; Marconi, Michael; Meng, Qing-Jun; Sládek, Martin; Adams, Jessica; Bass, Michael; Chandrasekaran, Rama; Butler, Todd; Griffor, Matt; Rajamohan, Francis; Serpa, Megan; Chen, Yuhpyng; Claffey, Michelle; Hastings, Michael; Loudon, Andrew; Maywood, Elizabeth; Ohren, Jeffrey; Doran, Angela; Wager, Travis T

2009-08-01

405

The small subunits of human and mouse DNA polymerase epsilon are homologous to the second largest subunit of the yeast Saccharomyces cerevisiae DNA polymerase epsilon.  

PubMed Central

Human DNA polymerase epsilon is composed of a 261 kDa catalytic polypeptide and a 55 kDa small subunit of unknown function. cDNAs encoding the small subunit of human and mouse DNA polymerase epsilon were cloned. The predicted polypeptides have molecular masses of 59.469 and 59.319 kDa respectively and they are 90% identical. The human and mouse polypeptides show 22% identity with the 80 kDa subunit of the five subunit DNA polymerase epsilon from the yeast Saccharomyces cerevisiae. The high degree of conservation suggests that the 55 kDa subunit shares an essential function with the yeast 80 kDa subunit, which was earlier suggested to be involved in S phase cell cycle control in a pathway that is able to sense and signal incomplete replication. The small subunits of human and mouse DNA polymerase epsilon also show homology to the C-terminal domain of the second largest subunit of DNA polymerase alpha. The gene for the small subunit of human DNA polymerase epsilon (POLE2) was localized to chromosome 14q21-q22 by fluorescence in situ hybridization. PMID:9443964

Jokela, M; Mäkiniemi, M; Lehtonen, S; Szpirer, C; Hellman, U; Syväoja, J E

1998-01-01

406

SYBR Green Real-Time PCR Method To Detect Clostridium botulinum Type A  

Microsoft Academic Search

Botulinum toxins (BoNTs) are classically produced by Clostridium botulinum but rarely also from neuro- toxigenic strains of Clostridium baratii and Clostridium butyricum. BoNT type A (BoNT\\/A), BoNT\\/B, BoNT\\/E, and very rarely BoNT\\/F are mainly responsible for human botulism. Standard microbiological methods take into consideration only the detection of C. botulinum. The presumptive identification of the toxigenic strains together with the

Lucia Fenicia; Fabrizio Anniballi; Dario De Medici; Elisabetta Delibato; Paolo Aureli

2007-01-01

407

40 Years of Calculus in 4 + epsilon Dimensions  

E-print Network

Modern physics describes elementary particles by a formalism known as Quantum Field Theory. However, straight calculations with this formalism lead to numerous divergences, hence one needs a suitable regularization scheme. 40 years ago a surprising scheme was established for this purpose: Dimensional Regularization. One computes in "4 + epsilon space-time dimensions", and takes the limit to our 4 dimensional space-time at the end. This method caused a revolution in particle physics, which led to the Standard Model. Many people refer to its results, and even apply it, without being aware that its history actually started in Latin America, more precisely in La Plata, Argentina. ----- La f\\'isica moderna describe a las part\\'iculas elementales por medio del formalismo conocido como Teor\\'ia Cu\\'antica de Campos. Sin embargo, los c\\'alculos directos realizados con este formalismo llevan a una gran cantidad de divergencias, por lo que es necesario un m\\'etodo para regularizarlos. Hace 40 a\\~nos se estableci\\'o un ...

Bietenholz, Wolfgang

2012-01-01

408

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

409

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

410

Infrared Studies of Epsilon Aurigae in Eclipse 2010  

NASA Astrophysics Data System (ADS)

We report a series of observations of the enigmatic long period eclipsing binary epsilon Aurigae during its eclipse interval 2009-2011, using near-infrared spectra & photometry obtained with SpeX/IRTF, Spitzer/IRAC, mid-infrared data with BASS on IRTF & AEOS, MIRSI on IRTF and MIRAC4 on MMT, along with MIRSI on IRTF and MIRAC4 on MMT & Denver's TNTCAM2 at WIRO, and an Optec SSP-4 J&H photometer at Mt.Evans Observatory. The objective of these observations include: (1) confirm the appearance of CO absorption bands at and after mid-eclipse, due to the dark disk, and (2) seek evidence for any mid-infrared solid state spectral features from particles in the disk, seen during different portions of total eclipse. The results to date show that the infrared eclipse is less deep than the optical one, and the implied disk temperature has begun to increase from 550K toward 1100K as eclipse progresses past midpoint and heated portions of the disk come into view. Material properties of the disk are consistent with large particles. 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 and JPL RSA 1414715 to the University of Denver, by NASA ADP grant NNX09AC73G to the University of Cincinnati, by The Aerospace Corporation's Independent Research and Development Program.

Stencel, Robert E.; Kloppenborg, B.; Wall, R.; Howell, S.; Hoard, D.; Rayner, J.; Bus, S.; Tokunaga, A.; Sitko, M.; Russell, R.; Lynch, D.; Brafford, S.; Hammel, H.; Whitney, B.; Orton, G.; Yanamandra-Fisher, P.; Hora, J.; Hoffman, W.; Skemer, A.

2011-01-01

411

Copernicus observations of the Ap star Epsilon Ursae Majoris  

NASA Technical Reports Server (NTRS)

Spectral scans of the Ap star Epsilon UMa made with the Copernicus satellite show strong line blanketing from profuse Cr II and Fe II lines. In the spectral region covering 1900 to 3000 A, about 500 lines are present which suppress the apparent continuum by at least 15-30%. An accurate line-identification list is compiled showing Eu II present in addition to Mn II and Ni II. The identification of Eu II, however, rests on very stringent identification limits for Fe II. If these are relaxed, the existence of Eu II is dubious. There are no broad features in this spectral region which would suggest strong photoionization discontinuities by metals, but one feature near 2137 A might contain the photoionization edge due to Cr I 5S lying 0.94 eV above the ground level. However, a significant correlation between the line-blanketing strength and the amplitude of the OAO-2 ultraviolet light curves was found such that both monotonically increase in the same proportion toward shorter wavelengths. This gives additional strength to the suggestion that variations in the metal line-blanketing cause the observed photometric variations.

Mallama, A. D.; Molnar, M. R.

1977-01-01

412

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

413

FT-IR spectroscopic analysis for studying Clostridium cell response to conversion of enzymatically hydrolyzed hay  

NASA Astrophysics Data System (ADS)

Grass hay is one of assailable cellulose containing non-food agricultural wastes that can be used as a carbohydrate source by microorganisms producing biofuels. In this study three Clostridium strains Clostridium acetobutylicum, Clostridium beijerinckii and Clostridium tetanomorphum, capable of producing acetone, butanol and ethanol (ABE) were adapted to convert enzymatically hydrolyzed hay used as a growth media additive. The results of growth curves, substrate degradation kinetics and FT-IR analyses of bacterial biomass macromolecular composition showed diverse strain-specific cell response to the growth medium composition.

Grube, Mara; Gavare, Marita; Nescerecka, Alina; Tihomirova, Kristina; Mezule, Linda; Juhna, Talis

2013-07-01

414

Discrimination of clostridium species using a magnetic bead based hybridization assay  

NASA Astrophysics Data System (ADS)

Clostridium chauvoei is the causative agent of blackleg, which is an endogenous bacterial infection. Mainly cattle and other ruminants are affected. The symptoms of blackleg are very similar to those of malignant edema, an infection caused by Clostridium septicum. [1, 2] Therefore a reliable differentiation of Clostridium chauvoei from other Clostridium species is required. Traditional microbiological detection methods are time consuming and laborious. Additionally, the unique identification is hindered by the overgrowing tendency of swarming Clostridium septicum colonies when both species are present. [1, 3, 4] Thus, there is a crucial need to improve and simplify the specific detection of Clostridium chauvoei and Clostridium septicum. Here we present an easy and fast Clostridium species discrimination method combining magnetic beads and fluorescence spectroscopy. Functionalized magnetic particles exhibit plentiful advantages, like their simple manipulation in combination with a large binding capacity of biomolecules. A specific region of the pathogenic DNA is amplified and labelled with biotin by polymerase chain reaction (PCR). These PCR products were then immobilized on magnetic beads exploiting the strong biotin-streptavidin interaction. The specific detection of different Clostridium species is achieved by using fluorescence dye labeled probe DNA for the hybridization with the immobilized PCR products. Finally, the samples were investigated by fluorescence spectroscopy. [5

Pahlow, Susanne; Seise, Barbara; Pollok, Sibyll; Seyboldt, Christian; Weber, Karina; Popp, Jürgen

2014-05-01

415

Epsilon carbide - A low-temperature component of interplanetary dust particles  

NASA Technical Reports Server (NTRS)

Transmission electron microscope study of a chondritic interplanetary dust particle has revealed the presence of epsilon iron-nickel carbide, a low-temperature carbide previously encountered only in metallurgical studies. In these studies epsilon-carbide was synthesized by carburization of iron or nickel grains in a stream of carbon monoxide or carbon monoxide plus hydrogen. Similar carburization of an iron-nickel metal in situ may have produced epsilon-carbide during particle heating on atmospheric entry or in solar orbit. Alternatively, the epsilon-carbide may be a by-product of Fischer-Tropsch reactions in the solar nebula. Such reactions have been proposed as the mechanism of hydrocarbon formation in the early solar system.

Christoffersen, R.; Buseck, P. R.

1983-01-01

416

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

417

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

418

Optimization Online - First-order algorithm with $O(ln(1/\\epsilon ...  

E-print Network

Apr 16, 2008 ... ... with an outer loop that lowers the target $\\epsilon$ between iterations (this target affects the amount of smoothing in the inner loop). ... the Mathematical Programming Society and by the Optimization Technology Center.

Andrew Gilpin

2008-04-16

419

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

420

SMIA Geneva September 2005 "Assessing Regional Sustainability with the EPSILON Project"  

E-print Network

dimension as defined by the UN Commission on Sustainable Development. A coherent objective based structure scale. An attempt to assess sustainability The main foreseen application of the EPSILON model [1 of sustainable development (social, economic, institutional and environmenta

Paris-Sud XI, Université de

421

Testing a low-Reynolds number k-epsilon turbulence model based on direct simulation data  

NASA Astrophysics Data System (ADS)

A low Re k-epsilon model based on direct numerical simulation (DNS) data proposed by Rodi and Mansour (1993) (RM) is discussed. The model was complemented by a damping function multiplying the destruction term in the model epsilon equation. The modified version of the RM model yielded generally good predictions of all major quantities in developed channel and boundary layer flows compared with the DNS data. The model is capable of correctly mimicking the c