Antimicrobial susceptibility of Clostridium perfringens isolated from domestic and wild animal species in Brazil

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Carlos Augusto de Oliveira Júnior

2016-02-01

Full Text Available Clostridium perfringens is a microorganism commonly found in the microbiota of humans and animals and a potential cause of enteric, muscle or nervous diseases. The treatment of these diseases is based on antimicrobial therapy and it is extremely important to know the antimicrobial susceptibility profile of the strains present in the region. The aim of this study was to evaluate the antimicrobial susceptibility of C. perfringens isolated from domestic and wild animals in Brazil against seven different antimicrobials. Forty-one strains from the stool samples of cattle (n = 12, buffalo (n = 2, goat (n = 3, dogs (n = 12 and wild carnivores (n = 12 were examined. The minimum inhibitory concentration was determined by the agar dilution method using Brucella agar supplemented with 5% of sheep blood, 0.1% of vitamin K, 0.1% of hemin and concentrations ranging from 0,25 to 256,0 mg L-1 of the following antibiotics: erythromycin, florfenicol, metronidazole, oxytetracycline, penicillin, tylosin, and vancomycin. All C. perfringens strains were susceptible to florfenicol, metronidazole, penicillin and vancomycin. Two strains (4.9% were resistant to erythromycin and tylosin, while five (12.2% were resistant to oxytetracycline, one of which (2.4% from an ocelot.

CLOSTRIDIUM PERFRINGENS IN MEAT AND MEAT PRODUCTS.

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HALL, H E; ANGELOTTI, R

1965-05-01

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.

Chitosan inhibits enterotoxigenic Clostridium perfringens type A in growth medium and chicken meat.

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Alnoman, Maryam; Udompijitkul, Pathima; Sarker, Mahfuzur R

2017-06-01

Clostridium perfringens is a spore-forming bacterium and a major cause of bacterial food-borne illness. In this study, we evaluated the inhibitory effects of chitosan against spore germination, spore outgrowth and vegetative growth of C. perfringens food poisoning (FP) isolates. Chitosan of differing molecular weights inhibited germination of spores of all tested FP isolates in a KCl germinant solution containing 0.1 mg/ml chitosan at pH 4.5. However, higher level (0.25 mg/ml) of chitosan was required to effectively arrest outgrowth of the germinated C. perfringens spores in Tripticase-yeast extract-glucose (TGY) medium. Furthermore, chitosan (1.0 mg/ml) was bacteriostatic against vegetative cells of C. perfringens in TGY medium. Although chitosan showed strong inhibitory activities against C. perfringens in laboratory medium, higher levels (2.0 mg/g) were required to achieve similar inhibition of spores inoculated into chicken meat. In summary, the inhibitory effects of chitosan against C. perfringens FP isolates was concentration dependent, and no major difference was observed when using different molecule weight chitosan as an inhibitor. Our results contribute to a better understanding on the potential application of chitosan in cooked meat products to control C. perfringens-associated disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clostridium difficile and Clostridium perfringens from wild carnivore species in Brazil.

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Silva, Rodrigo Otávio Silveira; D'Elia, Mirella Lauria; Tostes Teixeira, Erika Procópio; Pereira, Pedro Lúcio Lithg; de Magalhães Soares, Danielle Ferreira; Cavalcanti, Álvaro Roberto; Kocuvan, Aleksander; Rupnik, Maja; Santos, André Luiz Quagliatto; Junior, Carlos Augusto Oliveira; Lobato, Francisco Carlos Faria

2014-08-01

Despite some case reports, the importance of Clostridium perfringens and Clostridium difficile for wild carnivores remains unclear. Thus, the objective of this study was to identify C. perfringens and C. difficile strains in stool samples from wild carnivore species in Brazil. A total of 34 stool samples were collected and subjected to C. perfringens and C. difficile isolation. Suggestive colonies of C. perfringens were then analyzed for genes encoding the major C. perfringens toxins (alpha, beta, epsilon and iota) and the beta-2 toxin (cpb2), enterotoxin (cpe) and NetB (netb) genes. C. difficile strains were analyzed by multiplex-PCR for toxins A (tcdA) and B (tcdB) and a binary toxin gene (cdtB) and also submitted to a PCR ribotyping. Unthawed aliquots of samples positive for C. difficile isolation were subjected to the detection of A/B toxins by a cytotoxicity assay (CTA). C. perfringens was isolated from 26 samples (76.5%), all of which were genotyped as type A. The netb gene was not detected, whereas the cpb2 and cpe genes were found in nine and three C. perfringens strains, respectively. C. difficile was isolated from two (5.9%) samples. A non-toxigenic strain was recovered from a non-diarrheic maned wolf (Chrysocyon brachyurus). Conversely, a toxigenic strain was found in the sample of a diarrheic ocelot (Leopardus pardallis); an unthawed stool sample was also positive for A/B toxins by CTA, indicating a diagnosis of C. difficile-associated diarrhea in this animal. The present work suggests that wild carnivore species could carry C. difficile strains and that they could be susceptible to C. difficile infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

Toxinas de Clostridium perfringens Toxins of Clostridium perfringens

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W. E. Morris

2009-12-01

Full Text Available Clostridium perfringens es un bacilo grampositivo anaerobio con capacidad de formar esporas. Es uno de los patógenos bacterianos con mayor distribución en el medio ambiente, ya que puede ser aislado de muestras de suelo y de agua y además forma parte de la microbiota intestinal de animales y humanos. Sin embargo, en ciertas ocasiones puede actuar como patógeno oportunista y causar enfermedades como la gangrena gaseosa, la enterotoxemia del ovino y del caprino y la disentería del cordero, entre otras. En humanos, está asociado a enfermedades como la intoxicación por alimentos, la enterocolitis necrotizante en niños y la enteritis necrótica o pigbel de las tribus de Papúa-Nueva Guinea. El renovado interés que existe actualmente en el estudio de C. perfringens como patógeno veterinario y humano, junto con el avance de la biología molecular, han hecho posible que la ciencia tenga hoy un conocimiento más profundo sobre la biología y la patogenia de esta bacteria. En esta revisión bibliográfica se discuten y actualizan los principales aspectos de la patogenia intestinal de C. perfringens teniendo en cuenta las toxinas con mayor importancia médica descritas hasta el presente.Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled

Genotypic and phenotypic characterization of Clostridium perfringens isolates from Darmbrand cases in post-World War II Germany.

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Ma, Menglin; Li, Jihong; McClane, Bruce A

2012-12-01

Clostridium perfringens type C strains are the only non-type-A isolates that cause human disease. They are responsible for enteritis necroticans, which was termed Darmbrand when occurring in post-World War II Germany. Darmbrand strains were initially classified as type F because of their exceptional heat resistance but later identified as type C strains. Since only limited information exists regarding Darmbrand strains, this study genetically and phenotypically characterized seven 1940s era Darmbrand-associated strains. Results obtained indicated the following. (i) Five of these Darmbrand isolates belong to type C, carry beta-toxin (cpb) and enterotoxin (cpe) genes on large plasmids, and express both beta-toxin and enterotoxin. The other two isolates are cpe-negative type A. (ii) All seven isolates produce highly heat-resistant spores with D(100) values (the time that a culture must be kept at 100°C to reduce its viability by 90%) of 7 to 40 min. (iii) All of the isolates surveyed produce the same variant small acid-soluble protein 4 (Ssp4) made by type A food poisoning isolates with a chromosomal cpe gene that also produce extremely heat-resistant spores. (iv) The Darmbrand isolates share a genetic background with type A chromosomal-cpe-bearing isolates. Finally, it was shown that both the cpe and cpb genes can be mobilized in Darmbrand isolates. These results suggest that C. perfringens type A and C strains that cause human food-borne illness share a spore heat resistance mechanism that likely favors their survival in temperature-abused food. They also suggest possible evolutionary relationships between Darmbrand strains and type A strains carrying a chromosomal cpe gene.

Genetic characterization of type A enterotoxigenic Clostridium perfringens strains.

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Agi Deguchi

2009-05-01

Full Text Available 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.

Clostridium perfringens and C. difficile in parvovirus-positive dogs.

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Silva, Rodrigo Otávio Silveira; Dorella, Fernanda Alves; Figueiredo, Henrique Cesar Pereira; Costa, Érica Azevedo; Pelicia, Vanessa; Ribeiro, Bruna Letícia Devidé; Ribeiro, Marcio Garcia; Paes, Antonio Carlos; Megid, Jane; Lobato, Francisco Carlos Faria

2017-12-01

The aim of this study was to investigate Clostridium difficile and Clostridium perfringens in 82 diarrheic dogs positive for canine parvovirus type 2 (CPV). Enterotoxigenic C. perfringens type A was isolated from three (3.6%) dogs. One (1.2%) strain was also positive for NetE- and NetF-encoding genes, which are commonly associated with diarrhea in dogs. Toxigenic C. difficile was isolated from one animal (1.2%), which was also positive for A/B toxins. The present study identified C. difficile and C. perfringens infection in CPV-positive dogs. Further studies are necessary to clarify if clostridial infections may predispose or potentiate CPV-infection in dogs or vice versa. Copyright © 2017 Elsevier Ltd. All rights reserved.

Incidence and tracking of Clostridium perfringens through an integrated broiler chicken operation.

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Craven, S E; Cox, N A; Bailey, J S; Cosby, D E

2003-01-01

Clostridium perfringens has been shown to be widespread in the broiler chicken hatchery, grow-out, and processing operations. In a previous study, ribotypes of certain strains of C. perfringens isolated from processed chicken carcasses were shown to match ribotypes isolated from paper pad lining trays used to transport commercial chicks from the hatchery to the grow-out facility on the farm. These results suggest that C. perfringens contaminating the processed product could originate from facilities in the integrated poultry operation prior to grow out. In this study, samples were collected from the breeder farm, hatchery, previous grow-out flock, during grow out and after processing. In the first trial, C. perfringens was recovered from the breeder farms, the hatchery, previous grow-out flock, grow-out flock at 3 weeks of age, grow-out flock at 5 weeks of age, from processed carcasses, and from the breeder farm after processing in 4%, 30%, 4%, 0%, 2% and 16%, and 4% of the samples, respectively. In the second trial, the incidence of C. perfringens in samples collected from breeder farms, the hatchery, previous grow-out flock, grow-out flock at 3 weeks of age, grow-out flock at 5 weeks of age, and fromprocessed carcasses was 38%, 30%, 32%, 8%, 4%, and 8%, respectively. The genetic relatedness of the isolated strains as determined by ribotyping suggests that C. perfringens may be transmitted between facilities within the integrated broiler chicken operation.

Incidence of Clostridium perfringens in Broiler Chickens in the Czech Republic

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I. Svobodová

2007-01-01

Full Text Available Clostridium perfringens is a causative agent of human and animal foodborne diseases. It is known as a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen causing necrotic enteritis. The aim of the present study was to detect the incidence of C. perfringens in healthy broiler chickens. From May 2005 to September 2006, 609 samples of caecal content from broilers from 23 intensive poultry farms were analyzed. The samples were cultivated on TSC and blood agar, typical colonies were identified and biochemically confirmed. the total number of positive samples was 112 (18.39%. the samples were processed by the multiplex polymerase chain reaction method (PCR for toxin genotyping. The presence of alpha, beta, beta2 and enterotoxin gene was detected. All C. perfringens isolates were classified as type A, four isolates had the cpb2 gene. In conclusion the prevalence of C. perfringens-positive farms is approximately 74% and the amount ranges about 104 cfu/g of caecal content.

NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens.

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Anthony L Keyburn

2008-02-01

Full Text Available For over 30 years a phospholipase C enzyme called alpha-toxin was thought to be the key virulence factor in necrotic enteritis caused by Clostridium perfringens. However, using a gene knockout mutant we have recently shown that alpha-toxin is not essential for pathogenesis. We have now discovered a key virulence determinant. A novel toxin (NetB was identified in a C. perfringens strain isolated from a chicken suffering from necrotic enteritis (NE. The toxin displayed limited amino acid sequence similarity to several pore forming toxins including beta-toxin from C. perfringens (38% identity and alpha-toxin from Staphylococcus aureus (31% identity. NetB was only identified in C. perfringens type A strains isolated from chickens suffering NE. Both purified native NetB and recombinant NetB displayed cytotoxic activity against the chicken leghorn male hepatoma cell line LMH; inducing cell rounding and lysis. To determine the role of NetB in NE a netB mutant of a virulent C. perfringens chicken isolate was constructed by homologous recombination, and its virulence assessed in a chicken disease model. The netB mutant was unable to cause disease whereas the wild-type parent strain and the netB mutant complemented with a wild-type netB gene caused significant levels of NE. These data show unequivocally that in this isolate a functional NetB toxin is critical for the ability of C. perfringens to cause NE in chickens. This novel toxin is the first definitive virulence factor to be identified in avian C. perfringens strains capable of causing NE. Furthermore, the netB mutant is the first rationally attenuated strain obtained in an NE-causing isolate of C. perfringens; as such it has considerable vaccine potential.

Detection of enterotoxigenic Clostridium perfringens in meat samples by using molecular methods.

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Kaneko, Ikuko; Miyamoto, Kazuaki; Mimura, Kanako; Yumine, Natsuko; Utsunomiya, Hirotoshi; Akimoto, Shigeru; McClane, Bruce A

2011-11-01

To prevent food-borne bacterial diseases and to trace bacterial contamination events to foods, microbial source tracking (MST) methods provide important epidemiological information. To apply molecular methods to MST, it is necessary not only to amplify bacterial cells to detection limit levels but also to prepare DNA with reduced inhibitory compounds and contamination. Isolates carrying the Clostridium perfringens enterotoxin gene (cpe) on the chromosome or a plasmid rank among the most important food-borne pathogens. Previous surveys indicated that cpe-positive C. perfringens isolates are present in only ∼5% of nonoutbreak food samples and then only at low numbers, usually less than 3 cells/g. In this study, four molecular assays for the detection of cpe-positive C. perfringens isolates, i.e., ordinary PCR, nested PCR, real-time PCR, and loop-mediated isothermal amplification (LAMP), were developed and evaluated for their reliability using purified DNA. For use in the artificial contamination of meat samples, DNA templates were prepared by three different commercial DNA preparation kits. The four molecular assays always detected cpe when >10³ cells/g of cpe-positive C. perfringens were present, using any kit. Of three tested commercial DNA preparation kits, the InstaGene matrix kit appeared to be most suitable for the testing of a large number of samples. By using the InstaGene matrix kit, the four molecular assays efficiently detected cpe using DNA prepared from enrichment culture specimens of meat samples contaminated with low numbers of cpe-positive C. perfringens vegetative cells or spores. Overall, the current study developed molecular assay protocols for MST to detect the contamination of foods with low numbers of cells, and at a low frequency, of cpe-positive C. perfringens isolates.

Detection of Enterotoxigenic Clostridium perfringens in Meat Samples by Using Molecular Methods▿

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Kaneko, Ikuko; Miyamoto, Kazuaki; Mimura, Kanako; Yumine, Natsuko; Utsunomiya, Hirotoshi; Akimoto, Shigeru; McClane, Bruce A.

2011-01-01

To prevent food-borne bacterial diseases and to trace bacterial contamination events to foods, microbial source tracking (MST) methods provide important epidemiological information. To apply molecular methods to MST, it is necessary not only to amplify bacterial cells to detection limit levels but also to prepare DNA with reduced inhibitory compounds and contamination. Isolates carrying the Clostridium perfringens enterotoxin gene (cpe) on the chromosome or a plasmid rank among the most important food-borne pathogens. Previous surveys indicated that cpe-positive C. perfringens isolates are present in only ∼5% of nonoutbreak food samples and then only at low numbers, usually less than 3 cells/g. In this study, four molecular assays for the detection of cpe-positive C. perfringens isolates, i.e., ordinary PCR, nested PCR, real-time PCR, and loop-mediated isothermal amplification (LAMP), were developed and evaluated for their reliability using purified DNA. For use in the artificial contamination of meat samples, DNA templates were prepared by three different commercial DNA preparation kits. The four molecular assays always detected cpe when >103 cells/g of cpe-positive C. perfringens were present, using any kit. Of three tested commercial DNA preparation kits, the InstaGene matrix kit appeared to be most suitable for the testing of a large number of samples. By using the InstaGene matrix kit, the four molecular assays efficiently detected cpe using DNA prepared from enrichment culture specimens of meat samples contaminated with low numbers of cpe-positive C. perfringens vegetative cells or spores. Overall, the current study developed molecular assay protocols for MST to detect the contamination of foods with low numbers of cells, and at a low frequency, of cpe-positive C. perfringens isolates. PMID:21890671

Draft genome sequences of clostridium perfringens strain LLY_N11, a pathogenic isolate of necrotic enteritis from a healthy chicken

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Clostridium perfringens strain LLY_N11 is a commensal bacterial isolate from a healthy chicken that produced a necrotic enteritis in experimental studies. Here we present the assembly and annotation of its genome, which may provide further insights into improved understanding of the molecular mechan...

The majority of atypical cpb2 genes in Clostridium perfringens isolates of different domestic animal origin are expressed.

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Kircanski, Jasmina; Parreira, Valeria R; Whiteside, Samantha; Pei, Yanlong; Prescott, John F

2012-10-12

This study examined the prevalence and expression of the "consensus" and the "atypical"cpb2 genes in Clostridium perfringens isolates from cattle, chickens, dogs, goats, horses, pigs and sheep using polymerase chain reaction (PCR), sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting. Almost all porcine isolates (12/14) carried and expressed the consensus form of cpb2 but, when present in 108 non-porcine isolates, the gene was usually the atypical form (40 atypical versus 9 consensus). Western blotting showed expression in 30 of 40 (75%) atypical cpb2-positive isolates, considerably more frequently than reported previously. CPB2 was expressed by almost all (20/21) the consensus cpb2-positive isolates, regardless of source. Copyright © 2012 Elsevier B.V. All rights reserved.

Identification of novel Clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene.

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Kazuaki Miyamoto

Full Text Available Clostridium perfringens enterotoxin (CPE is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ∼65 kb. Complete sequence analysis of the ∼65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ∼65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains.

Toxin genotyping of Clostridium perfringens strains using a polymerase chain reaction protocol

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Elisabetta Di Giannatale

2010-03-01

Full Text Available A polymerase chain reaction protocol consisting of a multiplex to identify the cpa, cpb1, cpetx, cpi genes and a duplex to identify the cpe and cpb2 genes encoding for a, b1, e, i, enterotoxin and b2 toxins, respectively, was applied to DNA extracted from two collections of Clostridium perfringens strains. The first collection involved 19 isolates from rabbits. The second collection of 41 isolates came from routine necropsies. The cpa gene alone, or in association with the cpb2 gene, was detected in all DNA samples examined. The cpa gene, together with cpb2 gene, were detected in seven of the rabbit C. perfringens strains (36.8% and in nine isolates from necropsies (21.9%. The cpa gene was found in 63.2% of rabbit strains and 76.9% of strains from other animal species. In rabbits, the pathological lesions associated with C. perfringens detection were predominantly forms of non-inflammatory enteropathies. In other species, C. perfringens was mainly associated with congestive-haemorrhagic enteropathy, but also with fatal traumatic lesions, degenerative diseases and organs with post-mortem autolysis. No clear correlation was observed between detection of b2 toxin gene and species-specific pathological features.

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

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Yasugi, Mayo; Okuzaki, Daisuke; Kuwana, Ritsuko; Takamatsu, Hiromu; Fujita, Masaya; Sarker, Mahfuzur R; Miyake, Masami

2016-05-15

Clostridium perfringens type A is a common source of foodborne illness (FBI) in humans. Vegetative cells sporulate in the small intestinal tract and produce the major pathogenic factor C. perfringens enterotoxin. Although sporulation plays a critical role in the pathogenesis of FBI, the mechanisms inducing sporulation remain unclear. Bile salts were shown previously to induce sporulation, and we confirmed deoxycholate (DCA)-induced sporulation in C. perfringens strain NCTC8239 cocultured with human intestinal epithelial Caco-2 cells. In the present study, we performed transcriptome analyses of strain NCTC8239 in order to elucidate the mechanism underlying DCA-induced sporulation. Of the 2,761 genes analyzed, 333 were up- or downregulated during DCA-induced sporulation and included genes for cell division, nutrient metabolism, signal transduction, and defense mechanisms. In contrast, the virulence-associated transcriptional regulators (the VirR/VirS system, the agr system, codY, and abrB) were not activated by DCA. DCA markedly increased the expression of signaling molecules controlled by Spo0A, the master regulator of the sporulation process, whereas the expression of spo0A itself was not altered in the presence or absence of DCA. The phosphorylation of Spo0A was enhanced in the presence of DCA. Collectively, these results demonstrated that DCA induced sporulation, at least partially, by facilitating the phosphorylation of Spo0A and activating Spo0A-regulated genes in strain NCTC8239 while altering the expression of various genes. Disease caused by Clostridium perfringens type A consistently ranks among the most common bacterial foodborne illnesses in humans in developed countries. The sporulation of C. perfringens in the small intestinal tract is a key event for its pathogenesis, but the factors and underlying mechanisms by which C. perfringens sporulates in vivo currently remain unclear. Bile salts, major components of bile, which is secreted from the liver for

Use of single-enzyme amplified fragment length polymorphism for typing Clostridium perfringens isolated from diarrheic piglets Uso do polimorfismo do comprimento de fragmentos amplificados para tipagem de Clostridium perfringens isolados de suínos com diarréia

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Luciane Tieko Shinya

2006-09-01

Full Text Available Clostridium perfringens is an important pathogen in human and veterinary medicine. In swine, the agent is responsible for necrotic enteritis and enterotoxemia characterized by diarrhea, weight loss, delayed development and, in some cases, death. In the present study amplified fragment length polymorphism analyses (AFLP was used to characterize 54 C. perfringens strains isolated from swine presenting diarrhea. Analysis of the results showed 29 distinct profiles with discriminatory index equal to 0.97. Partial correlation between the origin of the isolates and groups was drawn, and correlation was possible in only 18.5% of the samples. Characterization of the strains in biotypes (A, B, C, D and E, production of beta-2 toxin and enterotoxin were performed by means of the polymerase chain reaction (PCR. Biotypes A, C and D were observed among the strains analyzed. All samples were positive for presence of the gene encoding beta-2 toxin and negative for the gene encoding enterotoxin. AFLP have shown to be a simple, fast, low cost method with high discriminative power and good reproducibility, presenting a great potential in epidemiological studies involving C. perfringens strains of animal origin.Clostridium perfringens é um importante agente infeccioso em medicina veterinária e humana. Em suínos, o agente é responsável pela enterite necrótica e enterotoxemia, caracterizadas por diarréia, perda de peso, atraso no desenvolvimento e morte. No presente estudo foi utilizado o polimorfismo do comprimento de fragmentos amplificados (AFLP, para caracterizar 54 isolados de C. perfringens obtidos de suínos com diarréia. A análise dos resultados do AFLP demonstrou 29 perfis distintos com índice discriminatório igual a 0,97. A correlação entre a origem dos isolados e os agrupamentos obtidos foi parcial, sendo apenas possível a correlação total de 18,5% das amostras estudadas. A caracterização das cepas em biotipos (A, B, C, D e E, produ

Characterization of a unique class C acid phosphatase from Clostridium perfringens.

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Reilly, Thomas J; Chance, Deborah L; Calcutt, Michael J; Tanner, John J; Felts, Richard L; Waller, Stephen C; Henzl, Michael T; Mawhinney, Thomas P; Ganjam, Irene K; Fales, William H

2009-06-01

Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was approximately 31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3' and 5' nucleoside monophosphates at pH 6. Calculated K(m)s ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 micromol of P(i)/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class.

Mastitis in dairy buffalo and cattle in Egypt due to Clostridium perfringens: prevalence, incidence, risk factors and costs.

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Osman, K M; El-Enbaawy, M I; Ezzeldeen, N A; Hussein, H M G

2009-12-01

Although Clostridium perfringens is recognised as an important cause of clostridial enteric diseases, there is only limited knowledge about the association of particular C. perfringens toxinotypes (types A to E) with mastitis in domestic animals. In this study, mastitis was detected in 213/623 (34.12%) and 8/83 (9.64%) of the quarter milk samples collected from cases of clinical mastitis in cows and buffalo, respectively. The micro-organism was isolated in an incidence of 16/357 (4.48%) of milk samples from cows and 1/25 (4.0%) of samples from buffalo. Infection in one quarter was the most typical situation found (83% in cows and 87% in buffalo). Clostridium perfringens infection was also correlated to the season, with the highest proportion of isolates being found during spring (10.71%) and winter (7.07%). Using the classical toxin neutralisation typing method, 17 strains, isolated from cow and buffalo milk, were identified as C. perfringens type A, and selected for molecular analysis. Polymerase chain reaction detected the oecpa gene while the P/cpb and e/etx genes went undetected. The authors believe that C. perfringens has the potential to produce disease on its own or to predispose the udder to disease caused by major mastitis and environmental pathogens.

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

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

2007-01-01

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

Application of Lactobacillus johnsonii expressing phage endolysin for control of Clostridium perfringens.

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Gervasi, T; Lo Curto, R; Minniti, E; Narbad, A; Mayer, M J

2014-10-01

Clostridium perfringens is frequently found in food and the environment and produces potent toxins that have a negative impact on both human and animal health and particularly on the poultry industry. Lactobacillus johnsonii FI9785, isolated from the chicken gastrointestinal tract, has been demonstrated to exclude Cl. perfringens in poultry. We have investigated the interaction of wild-type Lact. johnsonii FI9785 or an engineered strain expressing a cell wall-hydrolysing endolysin with Cl. perfringens in vitro, using a batch culture designed to simulate human gastrointestinal tract conditions. Co-culture experiments indicated that acid production by Lact. johnsonii is important in pathogen control. The co-culture of the endolysin-secreting Lact. johnsonii with Cl. perfringens showed that the engineered strain had the potential to control the pathogen, but the ability to reduce Cl. perfringens numbers was not consistent. Results obtained indicate that survival of high numbers of Lact. johnsonii will be essential for effective pathogen control. Significance and impact of the study: The bacterium Lactobacillus johnsonii FI9785 reduces numbers of the pathogen Clostridium perfringens in vitro. Biocontrol was improved by engineering the strain to produce and export a cell wall-hydrolysing endolysin, but good survival of the producer strain is essential. The production of bacteriophage endolysins by commensal bacteria has the potential to improve competitive exclusion of pathogens in the gastrointestinal tract. © 2014 The Society for Applied Microbiology.

Tips to Prevent Illness from Clostridium Perfringens

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... Some strains produce a toxin that causes diarrhea. What are common food sources of C. perfringens ? Meat and poultry are ... Anyone can get food poisoning from C. perfringens . What are the symptoms of C. perfringens food poisoning? People with C. perfringens food poisoning develop ...

Liver abscess and sepsis caused by Clostridium perfringens and Klebsiella oxytoca

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Christoph Paasch

Full Text Available Introduction: Clostridium (C perfringens and Klebsiella (K oxytoca are pathogenous human bacteria. Due to the production of several toxins C. perfringens is virulent by causing i.a. the necrotizing fasciitis, gas gangrene and hepatic abscess. K. oxytoca mostly causes infections of the respiratory and gastrointestinal tract. Presentation of case: We are presenting the case of a male patient at the age of 64, who suffered from nausea and progressive pain in the right upper abdomen. A computer tomography of the abdomen revealed a 7 × 5,6 cm sized entrapped air in liver segment VII. Later the patient developed a multiorgan failure. We then performed an explorative laparotomy. Intraoperatively it became clear that the liver was destructed presenting an open liver abscess (LA cavity of segment VII. The gallbladder was found inflamed. We successfully conducted the consistent debridement of segment VII and removed the gallbladder. Microbiological examination isolated C. perfringens and K. oxytoca. The patient survived undergoing antimicrobial and multimodal sepsis therapy. Discussion: The LA is a severe disease in surgery. In literature an overall mortality of 6–14% is described. Mostly bacterial infections of the biliary tract and the gallbladder are responsible for a LA. Abscesses with sepsis caused by both, C. perfringens and K. oxytoca, are highly perilous but rarely described in literature. Conclusion: When diagnosing an LA caused by C. perfringens an immediate surgical debridement and antimicrobial treatment is mandatory for the patient’s survival. Keywords: Liver abscess, Sepsis, Clostridium perfringens, Klebsiella oxytoca, Gas gangrene

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

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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

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.

Prevalence and characteristics of Clostridium perfringens and Clostridium difficile in dogs and cats attended in diverse veterinary clinics from the Madrid region.

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Álvarez-Pérez, Sergio; Blanco, José L; Harmanus, Celine; Kuijper, Ed J; García, Marta E

2017-12-01

Despite extensive research on the epidemiology of pathogenic clostridia in dogs and cats, most published studies focus on a selected animal population and/or a single veterinary medical centre. We assessed the burden of Clostridium perfringens and C. difficile shedding by small animals in 17 veterinary clinics located within the Madrid region (Spain) and differing in size, number and features of animals attended and other relevant characteristics. In addition, we studied the genetic diversity and antibiotic susceptibility of recovered isolates. Selective culture of all fecal specimens collected during a single week from dogs (n = 105) and cats (n = 37) attended in participating clinics yielded C. perfringens/C. difficile from 31%, 4.8% of the dogs, and 20%, 0% of the cats analyzed, respectively, and three dogs yielded both species. Furthermore, 17 animals (15 dogs and two cats) that yielded a positive culture for either species were recruited for a follow-up survey and C. perfringens was again obtained from nine dogs. Considerable differences in prevalence were observed among participating clinics for both clostridial species. C. perfringens isolates (n = 109) belonged to toxinotypes A (97.2%) and E (three isolates from one dog), whereas C. difficile isolates (n = 18) belonged to the toxigenic ribotypes 106 (33.3%) and 154 (16.7%), a 009-like ribotype (33.3%) and an unknown non-toxigenic ribotype (16.7%). Amplified fragment length polymorphism-based fingerprinting classified C. perfringens and C. difficile isolates into 105 and 15 genotypes, respectively, and tested isolates displayed in vitro resistance to benzylpenicillin (2.8%, 88.8%), clindamycin (0%, 16.7%), erythromycin (0.9%, 16.7%), imipenem (1.8%, 100%), levofloxacin (0.9%, 100%), linezolid (5.5%, 0%), metronidazole (4.6%, 0%) and/or tetracycline (7.3%, 0%). All animals from which multiple isolates were retrieved yielded ≥2 different genotypes and/or antimicrobial susceptibility profiles

Primeiro relato no Brasil de mastite necrótica bovina por Clostridium perfringens tipo A First report in Brazil of bovine necrotic mastitis due to Clostridium perfringens type A

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Luciana Aramuni Gonçalves

2006-08-01

Full Text Available Relata-se o primeiro caso no Brasil de mastite bovina por Clostridium perfringens tipo A. O quadro clínico caracterizou-se por necrose da papila mamária e porção ventral do quarto afetado. O agente foi isolado em cultura pura e identificado como tipo A por PCR a partir do leite do quarto mamário afetado.This report describes a case of bovine mastitis due to Clostridium perfringens type A for first time in Brazil. The unical case showed necrosis of papilla mammary and ventral portion of the affected quarter. The microorganism was isolated in pure culture and identified as type A by PCR from milk of the affected mammary quarter.

Effect of cooling on Clostridium perfringens in pea soup

NARCIS (Netherlands)

Jong, de A.E.I.; Rombouts, F.M.; Beumer, R.R.

2004-01-01

Foods associated with Clostridium perfringens outbreaks are usually abused after cooking. Because of their short generation times, C. perfringens spores and cells can grow out to high levels during improper cooling. Therefore, the potential of C. perfringens to multiply in Dutch pea soup during

Clostridium perfringens Sporulation and Sporulation-Associated Toxin Production

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Li, Jihong; Paredes-Sabja, Daniel; Sarker, Mahfuzur R.; McClane, Bruce A.

2015-01-01

The ability of Clostridium perfringens to form spores plays a key role during the transmission of this Gram-positive bacterium to cause disease. Of particular note, the spores produced by food poisoning strains are often exceptionally resistant to food environment stresses such as heat, cold and preservatives, which likely facilitates their survival in temperature-abused foods. The exceptional resistance properties of spores made by most type A food poisoning strains and some type C foodborne disease strains involves their production of a variant small acid soluble protein-4 that binds more tightly to spore DNA compared to the small acid soluble protein-4 made by most other C. perfringens strains. Sporulation and germination by C. perfringens and Bacillus spp. share both similarities and differences. Finally, sporulation is essential for production of C. perfringens enterotoxin, which is responsible for the symptoms of C. perfringens type A food poisoning, the second most common bacterial foodborne disease in the USA. During this foodborne disease, C. perfringens is ingested with food and then, using sporulation-specific alternate sigma factors, this bacterium sporulates and produces the enterotoxin in the intestines. PMID:27337447

Exposure to β-lactams results in the alteration of penicillin-binding proteins in Clostridium perfringens.

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Park, Miseon; Rafii, Fatemeh

2017-06-01

Clostridium perfringens causes a variety of mild to severe infections in humans and other animals. A decrease in the affinity of penicillin-binding protein (PBP) transpeptidases for β-lactams is considered one of the mechanisms of β-lactam resistance in bacteria. Two strains of C. perfringens isolated from bovines and one isolated from a chicken, which had decreased susceptibility to β-lactams, had variations in the amino acid sequences of the central penicillin-binding regions of the PBPs. β-Lactam-resistant mutants of another C. perfringens strain, ATCC 13124, were selected in vitro to determine the effects of exposure to β-lactams on the PBP genes. Cultures of the wild type rapidly developed resistance to penicillin G, cephalothin and ceftriaxone. The susceptibilities of all of the selected mutants to some other β-lactams also decreased. The largest PBP found in C. perfringens, CPF_2395, appeared to be the primary target of all three drugs. Strain resistant to penicillin G had mutation resulting in the substitution of one amino acid within the central penicillin-binding/transpeptidase domain, but the ceftrioxane and cephalothin-resistant strains had mutations resulting in the substitution of two amino acids in this region. The cephalothin-resistant mutant also had additional mutations in the CPF_0340 and CPF_2218 genes in this critical region. No other mutations were observed in the three other PBPs of the in vitro resistant mutants. Resistance development also altered the growth rate and cell morphology of the mutants, so in addition to the PBPs, some other genes, including regulatory genes, may have been affected during the interaction with β-lactam antibiotics. This is the first study showing the effects of β-lactam drugs on the substitution of amino acids in PBPs of C. perfringens and points to the need for studies to detect other unknown alterations affecting the physiology of resistant strains. Published by Elsevier Ltd.

Comparative genome analysis of clostridium perfringens isolates from healthy and necrotic enteritis infected poultry and diseased pigs

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Ronco, Troels; Lyhs, Ulrike; Stegger, Marc

2015-01-01

to be important for the development of NE in chickens and piglets, respectively, while the role of these toxins is less well elucidated in diseased turkeys. Methods: We carried out comparative genomic analysis of 40 C. perfringens genomes from healthy and NE-suffering chickens and turkeys, and diseased pigs using......B, NELoc-1 and -3 seem to play an important role in the NE pathogenesis in chickens, whereas cpb2 is important in diseased pigs. • The VirSR two-component system is involved in regulating NE-associated virulence genes. • Conjugative plasmid genes are widely spread among C. perfringens. • WGS is a powerful...

Prevalence of C. botulinum and C. perfringens spores in food products available on Polish market

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Grenda Tomasz

2017-09-01

Full Text Available Introduction: The aim of this study was to evaluate the prevalence of Clostridium botulinum and Clostridium perfringens in food samples purchased from Polish producers. Material and Methods: The analyses were performed on 260 food samples collected in Lublin and Subcarpathian regions: 56 of smoked meat, 21 of pork meat, 20 of dairy products, 26 of vegetable and fruit preserves, 40 of ready-to-eat meals, 27 of fish preserves, and 70 of honey collected directly from apiaries. Results: C. botulinum strains were isolated from 2.3% (6/260 of samples and the isolates were classified as toxin types A (4/260 and B (2/260. C. perfringens strains were isolated from 14% (37/260 of samples. All the isolates were classified as toxin type A, 28 of them were able also to produce α toxin and 9 - β2 toxin. Conclusion: On the basis of the obtained results it could be suggested that risk assessment, especially regarding the entire honey harvesting process, should be provided in order to ensure the microbiological safety of the products to be consumed by infants and people with a weakened immune system.

Growth of Clostridium perfringens during cooling of refried beans.

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Cevallos-Cevallos, Juan M; Akins, E Deann; Friedrich, Loretta M; Danyluk, Michelle D; Simonne, Amarat H

2012-10-01

Outbreaks of Clostridium perfringens have been associated with dishes containing refried beans from food service establishments. However, growth of C. perfringens in refried beans has not been investigated, and predictive models have not been validated in this food matrix. We investigated the growth of C. perfringens during the cooling of refried beans. Refried beans (pinto and black, with and without salt added) were inoculated with 3 log CFU/g C. perfringens spores and incubated isothermally at 12, 23, 30, 35, 40, 45, and 50°C. The levels of C. perfringens were monitored 3, 5, 8, and 10 h after inoculation, and then fitted to the Baranyi primary model and the Rosso secondary model prior to solving the Baranyi differential equation. The final model was validated by dynamic cooling experiments carried out in stockpots, thus mimicking the worst possible food service conditions. All refried beans samples supported the growth of C. perfringens, and all models fit the data with pseudo-R(2) values of 0.95 or greater and mean square errors of 0.3 or lower. The estimated maximum specific growth rates were generally higher in pinto beans, with or without salt added (2.64 and 1.95 h(-1), respectively), when compared with black beans, with or without salt added (1.78 and 1.61 h(-1), respectively). After 10 h of incubation, maximum populations of C. perfringens were significantly higher in samples with no salt added (7.9 log CFU/g for both pinto and black beans) than in samples with salt added (7.3 and 7.2 log CFU/g for pinto and black beans, respectively). The dynamic model predicted the growth of C. perfringens during cooling, with an average root mean squared error of 0.44. The use of large stockpots to cool refried beans led to an observed 1.2-log increase (1.5-log increase predicted by model) in levels of C. perfringens during cooling. The use of shallower pans for cooling is recommended, because they cool faster, therefore limiting the growth of C. perfringens.

Effect of tannins on the in vitro growth of Clostridium perfringens.

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Elizondo, Ana M; Mercado, Elsa C; Rabinovitz, Bettina C; Fernandez-Miyakawa, Mariano E

2010-10-26

Vegetable tannins are water-soluble polyphenolic compounds of varying molecular weights that occur abundantly in nature. The diet of many free-ranging wild animals contains significant amounts of tannins. Also, commercial tannins are used in animal industry as food additives to improve animal performance. In order to further determine the capacity of tannins to inhibit the development of intestinal diseases produced by Clostridium pefringens, we evaluated here the effect of tannins from quebracho, chestnut or combinations of both on C. perfringens and their toxins. The C. perfringens (types A, B, C, D and E) growth obtained from the intestine of healthy and diseased animals was reduced in a dose-dependent manner in the presence of quebracho tannins, chestnut tannins, combinations of both or a commercial formula based in these tannins. Although the minimal inhibitory concentration of both tannins varied between isolates, no statistically significant differences were observed between isolates from healthy or sick animals. Comparative analysis showed that the concentrations of quebracho tannin inhibiting the growth of C. perfringens were higher than chestnut tannin. In fact, antibacterial effect of quebracho tannin was increased up to 20 times with the addition of 25% of chestnut tannin and 85 times with 75% of chestnut tannin. Antibacterial activity of the commercial product was up to ~50 times higher than quebracho tannin alone. Quebracho tannin showed partial bactericidal activity, whereas chestnut tannin activity was stronger. Both tannins were able to reduce the alpha toxin lecithinase activity and epsilon toxin cytotoxicity in MDCK cells. These results suggest that tannin-supplemented diet could be useful to prevent some clostridial diseases. Copyright © 2010 Elsevier B.V. All rights reserved.

Behavior of Clostridium perfringens at low temperatures

NARCIS (Netherlands)

Jong, de A.E.I.; Rombouts, F.M.; Beumer, R.R.

2004-01-01

Refrigerated storage is an important step in the preparation of foods and inadequate storage is one of the main causes of food poisoning outbreaks of Clostridium perfringens. Therefore, growth and germination characteristics of C. perfringens in a temperature range of 3-42 degreesC were determined

Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium

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Miseon Park

2018-01-01

Full Text Available Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE, produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium.

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Park, Miseon; Rafii, Fatemeh

2018-01-01

Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens , which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

Cloning the enterotoxin gene from Clostridium perfringens type A

OpenAIRE

Iwanejko, Lesley Ann.

1991-01-01

A C. perfringens type A genomic library was constructed in E. coli by banking overlapping 6-10 kbp Hind III fragments of chromosomal DNA from the enterotoxin (CPE) positive strain NCTC 8239 into the pUC derived vector pHG165. The library was screened by colony hybridization with a degenerate 26 bp oligonucleotide probe, derived from the amino acid sequence CPE9_17A. complex mixture of plasmid DNA was isolated from the only hybridization positive clone. A second round of screening picked out a...

Experimental induction of abdominal tympany, abomasitis, and abomasal ulceration by intraruminal inoculation of Clostridium perfringens type A in neonatal calves.

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Roeder, B L; Chengappa, M M; Nagaraja, T G; Avery, T B; Kennedy, G A

1988-02-01

The etiologic role of Clostridum perfringens type A in the acute abdominal syndrome characterized by abomasal and rumen tympany, abomasitis, and abomasal ulceration was investigated in neonatal calves. Eight calves, 4 to 12 days old, were inoculated intraruminally with toxigenic C perfringens type A. Before and after C perfringens inoculation, blood samples were collected from all calves for blood gas and serum biochemical analysis and for determination of serum copper concentration; ruminal fluid was obtained for isolation of C perfringens. Calves were monitored daily for clinical signs of the syndrome and, depending on the severity of clinical signs, they were either euthanatized or redosed within 4 to 7 days. After necropsy, specimens obtained from the abomasum and rumen for macroscopic and microscopic examination and for anaerobic bacteriologic culture were processed in routine manner. Intraruminal inoculation of C perfringens type A into healthy calves induced anorexia, depression, bloat, diarrhea, and in some calves, death. Serum copper concentration was within normal range. Necropsy revealed variable degrees of abomasitis, petechial and ecchymotic hemorrhages, and ulcers (ranging from pinpoint to nearly perforate) in the abomasum. Seven of those calves also had multiple trichobezoars in the rumen. These necropsy findings were not seen in calves (controls) given distilled H2O only. In affected calves, acute abdominal syndrome was unrelated to copper deficiency, and C perfringens type A given intraruminally was able to induce clinical signs similar to those of the naturally acquired disease.

Beta Lactamase Producing Clostridium perfringens Bacteremia in an Elderly Man with Acute Pancreatitis

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Rashmi Mishra

2016-01-01

Full Text Available Clostridium perfringens bacteremia is associated with adverse outcomes. Known risk factors include chronic kidney disease, malignancy, diabetes mellitus, and gastrointestinal disease. We present a 74-year-old man admitted with confusion, vomiting, and abdominal pain. Exam revealed tachycardia, hypotension, lethargy, distended abdomen, and cold extremities. He required intubation and aggressive resuscitation for septic shock. Laboratory data showed leukocytosis, metabolic acidosis, acute kidney injury, and elevated lipase. CT scan of abdomen revealed acute pancreatitis and small bowel ileus. He was started on vancomycin and piperacillin-tazobactam. Initial blood cultures were positive for C. perfringens on day five. Metronidazole and clindamycin were added to the regimen. Repeat CT (day 7 revealed pancreatic necrosis. The patient developed profound circulatory shock requiring multiple vasopressors, renal failure requiring dialysis, and bacteremia with vancomycin-resistant enterococci. Hemodynamic instability precluded surgical intervention and he succumbed to multiorgan failure. Interestingly, our isolate was beta lactamase producing. We review the epidemiology, risk factors, presentation, and management of C. perfringens bacteremia. This case indicates a need for high clinical suspicion for clostridial sepsis and that extended spectrum beta lactam antibiotic coverage may be inadequate and should be supplemented with use of clindamycin or metronidazole if culture is positive, until sensitivities are known.

Tolerance of Clostridium perfringens biofilms to disinfectants commonly used in the food industry.

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Charlebois, Audrey; Jacques, Mario; Boulianne, Martine; Archambault, Marie

2017-04-01

Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Recently, it was shown to form mono-species biofilms, a structured community of bacterial cells enclosed in a self-produced extracellular matrix. Biofilms have been associated with tolerance to antibiotics, disinfectants, and physical and environmental stresses. Very little is known about the tolerance of C. perfringens biofilm toward disinfectants. In the present study, susceptibilities of C. perfringens biofilms to five types of commonly used disinfectants on farms and in food processing environments were analysed. In this paper, we show that C. perfringens mono-species biofilms can protect the bacterial cells from the action of potassium monopersulfate, quaternary ammonium chloride, hydrogen peroxide and glutaraldehyde solutions. However, sodium hypochlorite solution was shown to be effective on C. perfringens biofilms. Our investigation of dual-species biofilms of C. perfringens with the addition of Staphylococcus aureus or Escherichia coli demonstrated that overall, the mono-species biofilm of C. perfringens was more tolerant to all disinfectants than the dual-species biofilms. For the anaerobic grown biofilms, the mono-species biofilm of C. perfringens was more tolerant to sodium hypochlorite and quaternary ammonium chloride than the dual-species biofilms of C. perfringens with S. aureus or E. coli. This study demonstrates that C. perfringens biofilm is an effective protection mechanism to disinfectants commonly used on farms and in food processing environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recombinant Lactobacillus casei expressing Clostridium perfringens toxoids α, β2, ε and β1 gives protection against Clostridium perfringens in rabbits.

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Zhao, Li; Guo, Zhihou; Liu, Jiali; Wang, Zi; Wang, Ruichong; Li, Yijing; Wang, Li; Xu, Yigang; Tang, Lijie; Qiao, Xinyuan

2017-07-13

The present study used Lactobacillus casei ATCC 393 as antigen delivery system to express C. perfringens toxoids α-β2-ε-β1 to construct the recombination Lactobacillus casei pPG-2-α-β2-ε-β1/L. casei 393. After being induced by 1% xylose, the specificity and integrity of recombinant strain were determined by Western-blotting. Rabbits as native animal model were immunized orally with pPG-2-α-β2-ε-β1/L. casei 393 and the titers of specific IgG and sIgA were determined by ELISA. The result showed that oral administration with the recombinants could elicit both local mucosal and systemic immune responses. The proliferation of spleen lymphocytes in rabbits immunized with pPG-2-α-β2-ε-β1/L. casei 393 was observed. Levels of IL-4 and IFN-γ produced were significantly higher in lymphocytes isolated from the vaccine group than those from the control groups. Flow cytometry assay showed that both the percentages of CD4+T cells and CD8+T cells from the vaccine group were significantly increased than the control groups. All these results showed that immunizing with recombinants can elicit both humoral immunity and cellular immunity. Besides, in order to determine the effectiveness of oral immunization with pPG-2-α-β2-ε-β1/L. casei 393, rabbits of vaccine group and control groups were challenged with 1×LD 100 unit of culture filtrate of C. perfringens type C and type D toxins respectively. After challenge, 100% of the immunized rabbits survived, while the rabbits of the control group were killed within 48h. Observation on histopathology showed that histopathological changes were obviously found in heart, liver, spleen, lung, kidney, intestine and brain of rabbits from the control groups, while no apparent histopathological change was observed in the vaccine group. All the results show that pPG-2-α-β2-ε-β1/L. casei 393 can eliciteffective immunoprotection against C. perfringens. All of these suggest that the use of pPG-2-α-β2-ε-β1/L. casei 393 can be

Identification and Characterization of a New Enterotoxin Produced by Clostridium perfringens Isolated from Food Poisoning Outbreaks.

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Daisuke Irikura

Full Text Available There is a strain of Clostridium perfringens, W5052, which does not produce a known enterotoxin. We herein report that the strain W5052 expressed a homologue of the iota-like toxin components sa and sb of C. spiroforme, named Clostridium perfringens iota-like enterotoxin, CPILE-a and CPILE-b, respectively, based on the results of a genome sequencing analysis and a systematic protein screening. In the nicotinamide glyco-hydrolase (NADase assay the hydrolysis activity was dose-dependently increased by the concentration of rCPILE-a, as judged by the mass spectrometry analysis. In addition, the actin monomer of the lysates of Vero and L929 cells were radiolabeled in the presence of [32P]NAD and rCPILE-a. These findings indicated that CPILE-a possesses ADP-ribosylation activity. The culture supernatant of W5052 facilitated the rounding and killing of Vero and L929 cells, but the rCPILE-a or a non-proteolyzed rCPILE-b did not. However, a trypsin-treated rCPILE-b did. Moreover, a mixture of rCPILE-a and the trypsin-treated rCPILE-b enhanced the cell rounding and killing activities, compared with that induced by the trypsin-treated rCPILE-b alone. The injection of the mixture of rCPILE-a and the trypsin-treated rCPILE-b into an ileum loop of rabbits evoked the swelling of the loop and accumulation of the fluid dose-dependently, suggesting that CPILE possesses enterotoxic activity. The evidence presented in this communication will facilitate the epidemiological, etiological, and toxicological studies of C. perfringens food poisoning, and also stimulate studies on the transfer of the toxins' gene(s among the Genus Clostridium.

Strategy to inactivate Clostridium perfringens spores in meat products.

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Akhtar, Saeed; Paredes-Sabja, Daniel; Torres, J Antonio; Sarker, Mahfuzur R

2009-05-01

The current study aimed to develop an inactivation strategy for Clostridium perfringens spores in meat through a combination of spore activation at low pressure (100-200 MPa, 7 min) and elevated temperature (80 degrees C, 10 min); spore germination at high temperatures (55, 60 or 65 degrees C); and inactivation of germinated spores with elevated temperatures (80 and 90 degrees C, 10 and 20 min) and high pressure (586 MPa, at 23 and 73 degrees C, 10 min). Low pressures (100-200 MPa) were insufficient to efficiently activate C. perfringens spores for germination. However, C. perfringens spores were efficiently activated with elevated temperature (80 degrees C, 10 min), and germinated at temperatures lethal for vegetative cells (>or= 55 degrees C) when incubated for 60 min with a mixture of L-asparagine and KCl (AK) in phosphate buffer (pH 7) and in poultry meat. Inactivation of spores (approximately 4 decimal reduction) in meat by elevated temperatures (80-90 degrees C for 20 min) required a long germination period (55 degrees C for 60 min). However, similar inactivation level was reached with shorter germination period (55 degrees C for 15 min) when spore contaminated-meat was treated with pressure-assisted thermal processing (568 MPa, 73 degrees C, 10 min). Therefore, the most efficient strategy to inactivate C. perfringens spores in poultry meat containing 50 mM AK consisted: (i) a primary heat treatment (80 degrees C, 10 min) to pasteurize and denature the meat proteins and to activate C. perfringens spores for germination; (ii) cooling of the product to 55 degrees C in about 20 min and further incubation at 55 degrees C for about 15 min for spore germination; and (iii) inactivation of germinated spores by pressure-assisted thermal processing (586 MPa at 73 degrees C for 10 min). Collectively, this study demonstrates the feasibility of an alternative and novel strategy to inactivate C. perfringens spores in meat products formulated with germinants specific for C

The safe enterocin DD14 is a leaderless two-peptide bacteriocin with anti-Clostridium perfringens activity.

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Caly, Delphine L; Chevalier, Mickaël; Flahaut, Christophe; Cudennec, Benoit; Al Atya, Ahmed Khassaf; Chataigné, Gabrielle; D'Inca, Romain; Auclair, Eric; Drider, Djamel

2017-03-01

Enterococcus faecalis 14, a strain previously isolated from meconium, displayed activity against four Clostridium perfringens isolates when co-cultured on agar plates. The anti-Clostridium activity was ascribed to the production of enterocin DD14, which was subsequently purified. The minimum inhibitory concentration (MIC) of enterocin DD14 against one collection strain and one clinical C. perfringens strain was determined at 50 µg/mL. Furthermore, using the intestinal epithelial cell line IPEC-1, it was shown that E. faecalis 14 was not cytotoxic after 24 h of contact, and no cytotoxicity was observed when IPEC-1 cells were incubated with pure enterocin DD14 for 4 h. Enterocin DD14 was characterised using mass spectrometry and was shown to consist of two small proteins of 5200.74 Da and 5206.41 Da, respectively. The two peptides (DD14A and DD14B) have highly similar amino acid sequences and no signal peptide, which classifies enterocin DD14 as a class IIb leaderless two-peptide bacteriocin. The genes encoding DD14A and DD14B were sequenced and were shown to be 100% identical to other previously described enterocins MR10A and MR10B, in contrast to the producing strains, which are different. Consequently, the present in vitro study supports the potential of this E. faecalis 14 strain and/or its purified enterocin DD14 as putative anti-C. perfringens compounds in chickens. Copyright © 2017. Published by Elsevier B.V.

A toxic approach to beta2-toxigenic Clostridium perfringens

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Allaart, J.G.

2013-01-01

Clostridium perfringens is one of the most important causes of intestinal disease in animals and humans. Its virulence is attributed to the several toxins it can produce, including the beta2 toxin encoded by cpb2. In this thesis we studied the role of the beta2 toxin produced by C. perfringens in

Comparison of media for enumeration of Clostridium perfringens from foods

NARCIS (Netherlands)

Jong, A.E.I. de; Eijhusen, G.P.; Brouwer-Post, E.J.F.; Grand, M.; Johansson, T.; Kärkkäinen, T.; Marugg, J.; Veld, P.H. in 't; Warmerdam, F.H.M.; Wörner, G.; Zicavo, A.; Rombouts, F.M.; Beumer, R.R.

2003-01-01

Many media have been developed to enumerate Clostridium perfringens from foods. In this study, six media [iron sulfite (IS) agar, tryptose sulfite cycloserine (TSC) agar, Shahidi Ferguson perfringens (SFP) agar, sulfite cycloserine azide (SCA), differential clostridial agar (DCA), and oleandomycin

Caracterización molecular y resistencia antimicrobiana de aislamientos de Clostridium perfringens de diferentes orígenes en Costa Rica

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María del Mar Gamboa-Coronado

2011-12-01

Full Text Available Clostridium perfringens es un bacilo Gram positivo, esporulado, anaerobio, ampliamente distribuido en la naturaleza, que produce cuatro toxinas principales α, β, ε y ι, las cuales permiten su clasificación en cinco toxinotipos (A-E. Algunas cepas producen una enterotoxina (CPE, codificada por el gen cpe, que causa diarrea en seres humanos y en algunos animales. La presencia de los genes de estas toxinas y la sensibilidad a los antibióticos se determinó en 81 cepas de C. perfringens previamente aisladas y que habían sido mantenidas a -80°C; 20 de suelos, 20 de origen animal, 20 de origen humano y 21 de alimentos cocidos no relacionados con brotes alimentarios. De acuerdo con los resultados de PCR, todas las cepas fueron clasificadas como C. perfringens tipo A, debido a que solo se les detectó el gen de la toxina α, mientras que el gen de la enterotoxina (cpe se detectó en dos cepas (2.5% aisladas de alimentos, tal como ha sido descrito en otras regiones del mundo. El 44% de las cepas fue resistente a algún antibiótico; clindamicina (41%, cloranfenicol (25%, penicilina (22% y metronidazol (20%. En general, las cepas provenientes de suelos presentaron los mayores porcentajes de resistencia a casi todos los antibióticos. El 40% de las cepas de suelo presentó multiresistencia (a tres o más grupos de antibióticos, el 30% de las de origen humano, el 14% de las de alimentos y el 5% de las de origen animal. Las altas tasas de resistencia encontradas podrían deberse al amplio uso de antibióticos como promotores de crecimiento de plantas y animales y esas cepas resistentes podrían actuar como reservorio de genes de resistencia que pueden transferirse entre bacterias de diversos ambientes.Molecular characterization and antimicrobial resistance of Clostridium perfringens isolates of different origins from Costa Rica. Clostridium perfringens, a Gram positive, spore-forming anaerobe, is widely distributed in nature. Based upon their

Molecular typing and antimicrobial susceptibility of Clostridium perfringens from broiler chickens.

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Gharaibeh, Saad; Al Rifai, Rami; Al-Majali, Ahmad

2010-12-01

Clostridium perfringens (Cp) causes necrotic enteritis disease in commercial poultry. Antimicrobials are used to control and treat this disease and sometimes clinical outbreaks do not respond well to certain treatments. This study was designed to isolate Cp from clinical cases, type these isolates by multiplex PCR, and determine their antimicrobial susceptibility by micro-dilution method. A total of 67 Cp isolates were obtained from 155 broiler chicken flocks. All isolates were classified as type A and non-enterotoxin producers. Lincomycin, erythromycins, and tilmicosin showed very high minimal inhibitory concentration (MIC) 50 of ≥256 μg/ml. However, tylosin, amoxicillin, ampicillin, penicillin, florfenicol, danofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline had variable MIC₅₀ of 64, 0.5, 1, 1, 8, 4, 8, 4, 8, 0.5 μg/ml, respectively. It is recommended that Cp infections in Jordan be treated with either penicillins or tetracyclines especially amoxicillin and oxytetracycline. Copyright © 2010 Elsevier Ltd. All rights reserved.

Clostridium perfringens in London, July 2009: two weddings and an outbreak.

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Eriksen, J; Zenner, D; Anderson, S R; Grant, K; Kumar, D

2010-06-24

Food poisoning outbreaks caused by Clostridium perfringens enterotoxin occur occasionally in Europe but have become less common in recent years. This paper presents the microbiological and epidemiological results of a large C. perfringens outbreak occurring simultaneously at two weddings that used the same caterer. The outbreak involved several London locations and required coordination across multiple agencies. A case-control study (n=134) was carried out to analyse possible associations between the food consumed and becoming ill. Food, environmental and stool samples were tested for common causative agents, including enterotoxigenic C. perfringens. The clinical presentation and the epidemiological findings were compatible with C. perfringens food poisoning and C. perfringens enterotoxin was detected in stool samples from two cases. The case-control study found statistically significant associations between becoming ill and eating either a specific chicken or lamb dish prepared by the same food handler of the implicated catering company. A rapid outbreak investigation with preliminary real-time results and the successful collaboration between the agencies and the caterer led to timely identification and rectification of the failures in the food handling practices.

Quantitative Detection of Clostridium perfringens in Broiler Chickens by Real-Time PCR Targeting the Alpha-Toxin Gene

DEFF Research Database (Denmark)

Abildgaard, Lone; Engberg, Ricarda M.; Schramm, Andreas

2006-01-01

was developed by sequencing the α-toxin gene from ~60 strains of C. perfringens, isolated from diseased as well as healthy broilers. For its application to the chicken gastrointestinal tract (i.e., ileum), DNA extraction efficiency and potential inhibition of the real-time PCR process by ileum content...

Experimental Clostridium perfringens type D enterotoxemia in goats.

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Uzal, F A; Kelly, W R

1998-03-01

The effects of intraduodenal administration of Clostridium perfringens cultures and culture products in goats were evaluated to develop a reliable experimental model of enterotoxemia in this species. Five conventionally reared, 11-16-week-old Angora goat kids were dosed intraduodenally with whole cultures of C. perfringens type D; five similar animals were dosed with C. perfringens type D filtered culture supernatant; and a third group of five kids was dosed with C. perfringens type D washed cells. Two kids were used as controls and received sterile, nontoxic culture medium intraduodenally. All animals received starch solution into the abomasum. All five kids inoculated with whole culture and three of five dosed with culture supernatant and with washed cells developed central nervous system signs. Diarrhea was observed in two of five kids inoculated with whole culture, in all five of those dosed with culture supernatant, and in three of five of those that received washed cells. The most striking postmortem findings consisted of lung edema, necrotizing pseudomembranous colitis, and cerebral vasogenic edema. The protocol thus provided a reasonable model of naturally occurring enterotoxemia in goats, producing a range of clinical signs and postmortem changes similar to those observed in the natural disease.

Perfringolysin O: The Underrated Clostridium perfringens Toxin?

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Verherstraeten, Stefanie; Goossens, Evy; Valgaeren, Bonnie; Pardon, Bart; Timbermont, Leen; Haesebrouck, Freddy; Ducatelle, Richard; Deprez, Piet; Wade, Kristin R; Tweten, Rodney; Van Immerseel, Filip

2015-05-14

The anaerobic bacterium Clostridium perfringens expresses multiple toxins that promote disease development in both humans and animals. One such toxin is perfringolysin O (PFO, classically referred to as θ toxin), a pore-forming cholesterol-dependent cytolysin (CDC). PFO is secreted as a water-soluble monomer that recognizes and binds membranes via cholesterol. Membrane-bound monomers undergo structural changes that culminate in the formation of an oligomerized prepore complex on the membrane surface. The prepore then undergoes conversion into the bilayer-spanning pore measuring approximately 250-300 Å in diameter. PFO is expressed in nearly all identified C. perfringens strains and harbors interesting traits that suggest a potential undefined role for PFO in disease development. Research has demonstrated a role for PFO in gas gangrene progression and bovine necrohemorrhagic enteritis, but there is limited data available to determine if PFO also functions in additional disease presentations caused by C. perfringens. This review summarizes the known structural and functional characteristics of PFO, while highlighting recent insights into the potential contributions of PFO to disease pathogenesis.

Perfringolysin O: The Underrated Clostridium perfringens Toxin?

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Stefanie Verherstraeten

2015-05-01

Full Text Available The anaerobic bacterium Clostridium perfringens expresses multiple toxins that promote disease development in both humans and animals. One such toxin is perfringolysin O (PFO, classically referred to as θ toxin, a pore-forming cholesterol-dependent cytolysin (CDC. PFO is secreted as a water-soluble monomer that recognizes and binds membranes via cholesterol. Membrane-bound monomers undergo structural changes that culminate in the formation of an oligomerized prepore complex on the membrane surface. The prepore then undergoes conversion into the bilayer-spanning pore measuring approximately 250–300 Å in diameter. PFO is expressed in nearly all identified C. perfringens strains and harbors interesting traits that suggest a potential undefined role for PFO in disease development. Research has demonstrated a role for PFO in gas gangrene progression and bovine necrohemorrhagic enteritis, but there is limited data available to determine if PFO also functions in additional disease presentations caused by C. perfringens. This review summarizes the known structural and functional characteristics of PFO, while highlighting recent insights into the potential contributions of PFO to disease pathogenesis.

Riverbed sediments in the Apies River, South Africa: recommending the use of both Clostridium perfringens and Escherichia coli as indicators of faecal pollution

CSIR Research Space (South Africa)

Abia, ALK

2015-12-01

Full Text Available . Real-time polymerase chain reaction (RT-PCR) was used to confirm isolates. E. coli and C. perfringens were enumerated in sediment by firstly using the water displacement approach to dislodge organisms from sediment and then subsequently followed...

Reproducible Infection Model for Clostridium perfringens in Broiler Chickens

DEFF Research Database (Denmark)

Pedersen, Karl; Friis-Holm, Lotte Bjerrum; Heuer, Ole Eske

2008-01-01

, 18, 20, and 24 ( Experiment 2). There was no mortality in any of the groups; however, chickens in the groups receiving both coccidial vaccine and C. perfringens developed the subclinical form of necrotic enteritis, demonstrated by focal necroses in the small intestine, whereas chickens in control...... groups or groups receiving only coccidial vaccine or only C. perfringens cultures developed no necroses. The results underline the importance of predisposing factors in the development of necrotic enteritis....

Optimizing sporulation of Clostridium perfringens

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Jong, de A.E.I.; Beumer, R.R.; Rombouts, F.M.

2002-01-01

Many sporulation media have been developed for Clostridium perfringens, but none stimulates sporulation for all strains. The aim of our experiments was to develop a sporulation method using Duncan and Strong (DS) medium, which supports sporulation of a wide variety of strains. Different inoculation

A rapid qualitative assay for detection of Clostridium perfringens in canned food products.

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Dave, Gayatri Ashwinkumar

2017-01-01

Clostridium perfringens (MTCC 1349) is a Gram-positive, anaerobic, endospore forming, and rod-shaped bacterium. This bacterium produces a variety of toxins under strict anaerobic environment. C. perfringens can grow at temperatures ranging between 20°C and 50°C. It is the major causetive agent for gas gangrene, cellulitis, septicemia, necrotic enteritis and food poisoning, which are common toxin induced conditions noted in human and animals. C. perfringens can produce produce four major types of toxins that are used for the classification of strains, classified under type A-E. Across the globe many countries, including the United States, are affected by C. perfringens food poisonings where it is ranked as one of the most common causes of food borne infections. To date, no direct one step assay for the detection of C. perfringens has been developed and only few methods are known for accurate detection of C. perfringens. Long detection and incubation time is the major consideration of these reporter assays. The prensent study proposes a rapid and reliable colorimetric assay for the detection of C. perfringens. In principale, this assay detects the para nitrophenyl (yellow colour end product) liberated due to the hydrolysis of paranitrophenyl phosphetidyl choline (PNPC) through phospholipase C (lecithinase). Constitutive secretion of phospholipase C is a charactristic feature of C. perfringens. This assay detects the presence of the extracellular lecithinse through the PNPC impragnated impregnated probe. The probe is impregnated with peranitrophenyl phosphotidyl choline ester, which is colourless substrate used by lecithinase. The designed assay is specific towards PNPC and detectes very small quantites of lecithinase under conditions used. The reaction is substrate specific, no cross reaction was observed upon incubation with other substrates. In addition, this assay gave negative results with other clostridium strains, no cross reactions were observed with other

Molecular characterization of podoviral bacteriophages virulent for Clostridium perfringens and their comparison with members of the Picovirinae.

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Nikolay V Volozhantsev

Full Text Available Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium responsible for human food-borne disease as well as non-food-borne human, animal and poultry diseases. Because bacteriophages or their gene products could be applied to control bacterial diseases in a species-specific manner, they are potential important alternatives to antibiotics. Consequently, poultry intestinal material, soil, sewage and poultry processing drainage water were screened for virulent bacteriophages that lysed C. perfringens. Two bacteriophages, designated ΦCPV4 and ΦZP2, were isolated in the Moscow Region of the Russian Federation while another closely related virus, named ΦCP7R, was isolated in the southeastern USA. The viruses were identified as members of the order Caudovirales in the family Podoviridae with short, non-contractile tails of the C1 morphotype. The genomes of the three bacteriophages were 17.972, 18.078 and 18.397 kbp respectively; encoding twenty-six to twenty-eight ORF's with inverted terminal repeats and an average GC content of 34.6%. Structural proteins identified by mass spectrometry in the purified ΦCP7R virion included a pre-neck/appendage with putative lyase activity, major head, tail, connector/upper collar, lower collar and a structural protein with putative lysozyme-peptidase activity. All three podoviral bacteriophage genomes encoded a predicted N-acetylmuramoyl-L-alanine amidase and a putative stage V sporulation protein. Each putative amidase contained a predicted bacterial SH3 domain at the C-terminal end of the protein, presumably involved with binding the C. perfringens cell wall. The predicted DNA polymerase type B protein sequences were closely related to other members of the Podoviridae including Bacillus phage Φ29. Whole-genome comparisons supported this relationship, but also indicated that the Russian and USA viruses may be unique members of the sub-family Picovirinae.

The incidence of Clostridioides difficile and Clostridium perfringens netF-positive strains in diarrheic dogs.

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Diniz, Amanda Nadia; Coura, Fernanda Morcatti; Rupnik, Maja; Adams, Vicki; Stent, Thomas L; Rood, Julian I; de Oliveira, Carlos Augusto; Lobato, Francisco Carlos Faria; Silva, Rodrigo Otávio Silveira

2018-02-01

The aim of this study was to examine the incidence of Clostridioides (previously Clostridium) difficile and Clostridium perfringens in the feces of diarrheic and non-diarrheic dogs. Also, the presence of other common canine enteropathogens was examined. Toxigenic C. difficile and C. perfringens positive for the NetF-encoding gene (netF) were detected in 11 (11.9%) and seven (7.6%) diarrheic dogs, respectively. Three dogs were diagnosed simultaneously with toxigenic C. difficile and netF-positive C. perfringens. Among other enteropathogens, Giardia sp. was the most common agent detected in dogs positive for toxigenic C. difficile or netF-positive C. perfringens. The results suggest that C. difficile and C. perfringens occur more frequently as a primary cause of diarrhea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clostridium perfringens types A and D associated with enterotoxemia in an 18-month-old goat

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S. Miyashiro

2007-01-01

Full Text Available Postmortem examination of a Boer buck that died peracutely revealed bowel and liver diffusely congested and edematous. Kidney was apparently edematous. Clostridium perfringens type A was isolated from bowel and type D from kidney. Microscopic examination revealed large areas of necrosis in the renal cortex and medulla (pulpy kidney disease, hyperemia and centrilobular necrosis of the liver, necrosis of the small-intestine wall, pulmonary edema and congestion, intense hyperemia of the cerebellum, hyperemia and edema of the brain.

Hazard analysis of Clostridium perfringens in the Skylab Food System

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

1974-01-01

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.

Uterine Clostridium perfringens infection related to gynecologic malignancy.

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Kremer, Kevin M; McDonald, Megan E; Goodheart, Michael J

2017-11-01

Uterine gas gangrene caused by Clostridium perfringens is a serious, often life-threatening infection that is rarely encountered in the practice of gynecologic oncology. However, the hypoxic nature of gynecologic cancers due to necrosis and/or prior radiation therapy creates a microenvironment optimal for proliferation of anaerobic bacteria such as the Clostridium species. Early recognition and aggressive treatment with IV antibiotics and surgical debridement remain the cornerstones of management in order to decrease morbidity and mortality. Here we present the case of a 52 year-old woman with a remote history of cervical cancer who was previously treated at our institution with primary chemotherapy and radiation and was then admitted decades later with Clostridium perfringens bacteremia and CT evidence of intrauterine abscess. The patient received a prolonged course of IV antibiotic therapy and subsequently underwent definitive surgical management with a total abdominal hysterectomy, bilateral salpingo-oophorectomy, small bowel resection with anastomosis for a utero-ileal fistula identified intraoperatively. Pathology from the uterine specimen demonstrated a primary poorly differentiated uterine adenocarcinoma. The patient recovered fully from her Clostridium perfringens infection and was discharged from the hospital shortly after surgical intervention.

Lipoproteins from Clostridium perfringens and their protective efficacy in mouse model.

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Dwivedi, Pratistha; Alam, Syed Imteyaz; Kumar, Om; Kumar, Ravi Bhushan

2015-08-01

Clostridium perfringens is an obligately anaerobic rod-shaped bacterium and etiological agent for several diseases in humans and animals. The pathogen has been listed as Validated Biological Agent and warrants development of medical countermeasures. The homologs of some of the lipoproteins identified from various fractions of C. perfringens in our previous studies were observed to be virulence determinants in other pathogenic bacteria. Three putative virulence associated lipoproteins; polysaccharide deacetylase family protein, probable ion-uptake ABC transporter, and a putative lipoprotein of no known function are reported here with respect to their immuno-protective potentials. The three proteins were over expressed and purified to near homogeneity. The lipoproteins were shown to be exposed on the C. perfringens surface and, hence, accessible to antibodies and potentially visible to the host immune system. Immunization of mice with purified recombinant proteins elicited protective immunity against challenge with C. perfringens in mouse gas gangrene model. Distribution and relationship of orthologous proteins across other bacterial select agents especially among the members of Firmicutes, was carried out to look for conserved antigenic determinants. Copyright © 2015 Elsevier B.V. All rights reserved.

Sialidases affect the host cell adherence and epsilon toxin-induced cytotoxicity of Clostridium perfringens type D strain CN3718.

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Jihong Li

2011-12-01

Full Text Available Clostridium perfringens type B or D isolates, which cause enterotoxemias or enteritis in livestock, produce epsilon toxin (ETX. ETX is exceptionally potent, earning it a listing as a CDC class B select toxin. Most C. perfringens strains also express up to three different sialidases, although the possible contributions of those enzymes to type B or D pathogenesis remain unclear. Type D isolate CN3718 was found to carry two genes (nanI and nanJ encoding secreted sialidases and one gene (nanH encoding a cytoplasmic sialidase. Construction in CN3718 of single nanI, nanJ and nanH null mutants, as well as a nanI/nanJ double null mutant and a triple sialidase null mutant, identified NanI as the major secreted sialidase of this strain. Pretreating MDCK cells with NanI sialidase, or with culture supernatants of BMC206 (an isogenic CN3718 etx null mutant that still produces sialidases enhanced the subsequent binding and cytotoxic effects of purified ETX. Complementation of BMC207 (an etx/nanH/nanI/nanJ null mutant showed this effect is mainly attributable to NanI production. Contact between BMC206 and certain mammalian cells (e.g., enterocyte-like Caco-2 cells resulted in more rapid sialidase production and this effect involved increased transcription of BMC206 nanI gene. BMC206 was shown to adhere to some (e.g. Caco-2 cells, but not all mammalian cells, and this effect was dependent upon sialidase, particularly NanI, expression. Finally, the sialidase activity of NanI (but not NanJ or NanH could be enhanced by trypsin. Collectively these in vitro findings suggest that, during type D disease originating in the intestines, trypsin may activate NanI, which (in turn could contribute to intestinal colonization by C. perfringens type D isolates and also increase ETX action.

Uterine Sarcoma Presenting with Sepsis from Clostridium perfringens Endometritis in a Postmenopausal Woman

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Mary J. Kao

2018-01-01

Full Text Available Clostridium perfringens is an anaerobic gram positive rod that is found in normal vaginal and cervical flora in 1–10% of healthy women. Uterine infection with Clostridium perfringens is seen rarely but is often related to underlying uterine pathology and can progress quickly to sepsis. Early recognition of sepsis, prompt treatment with antibiotics, and source control with surgical management allow for optimal chance of recovery. We present a case of a postmenopausal woman who presented with sepsis, vaginal bleeding, and back pain who was found to have Clostridium perfringens infection in the setting of undifferentiated uterine sarcoma.

Pancreatitis caused by Clostridium perfringens infection with extensive retropneumoperitoneum

International Nuclear Information System (INIS)

Merchante, E.; Garcia, F. J.; Perez, H.; Marquez, J. L.

2001-01-01

We present a case of primary emphysematous pancreatitis caused by Clostridium perfringens infection (also Known as spontaneous pancreatic gas gangrene) in a 66-year-old man with diabetes and a history of recurrent pancreatitis. One notable feature is the absence of a focal distribution, which is seen on radiological studies to be accompanied by extensive retropneumoperitoneum, with dissemination of the gas toward the mesenteric root and pelvic extra peritoneal spaces. This wide diffusion is aided by the C. perfringens toxins and the pancreatic enzymes released, leading to a fulminate course, an elevated rate of early mortality among the cases reviewed. The early diagnosis of this disease is fundamental, enabling aggressive medical treatment and emergency surgery. Diabetes is a known risk factor for anaerobic infection, including C. perfringens, as in the case of emphysematous cholecystitis. A diseased pancreas or pancreatic duct facilitates the development of infections since it eliminates poorly the microorganisms that reach it from the duodenum. Gas gangrene secondary to necrosis-related super infection or pancreatic collections is uncommon, and spontaneous or primary cases are exceptionally are. (Author) 13 refs

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

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Marie-Lou Gaucher

2017-05-01

Full Text Available Extensive use of antibiotic growth promoters (AGPs in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

Science.gov (United States)

Gaucher, Marie-Lou; Perron, Gabriel G.; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

2017-01-01

Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time. PMID:28567032

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population.

Science.gov (United States)

Gaucher, Marie-Lou; Perron, Gabriel G; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

2017-01-01

Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

Recent Insights into Clostridium perfringens Beta-Toxin

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Masahiro Nagahama

2015-02-01

Full Text Available Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin.

Clostridium perfringens in London, July 2009: two weddings and an outbreak.

OpenAIRE

Eriksen, J.; Zenner, D.; Anderson, S. R.; Grant, K.; Kumar, D.

2010-01-01

: Food poisoning outbreaks caused by Clostridium perfringens enterotoxin occur occasionally in Europe but have become less common in recent years. This paper presents the microbiological and epidemiological results of a large C. perfringens outbreak occurring simultaneously at two weddings that used the same caterer. The outbreak involved several London locations and required coordination across multiple agencies. A case-control study (n=134) was carried out to analyse possible associations b...

EPIDEMIOLOGIC INVESTIGATION OF CLOSTRIDIUM DIFFICILE AND CLOSTRIDIUM PERFRINGENS IN HEALTHY HORSES

DEFF Research Database (Denmark)

Schoster, Angelika; Arroyo, Luis; Staempfli, Henry

Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other ...... supports results of previous studies that indicate this organism is rare in healthy horses.......Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other...... than feces and variability in shedding over time. The objectives were to investigate the presence of C. difficile and C. perfringens in healthy horses over time and assess prevalence in different gastrointestinal compartments. Feces were collected monthly from 25 horses for one year. Ingesta were...

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

OpenAIRE

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

2006-01-01

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.

Bacillus subtilis and yeast cell wall improve the intestinal health of broilers challenged by Clostridium perfringens.

Science.gov (United States)

Li, Z; Wang, W; Lv, Z; Liu, D; Guo, Y

2017-12-01

1. The objective was to investigate the effects of Bacillus subtilis, yeast cell wall (YCW) and their combination on intestinal health of broilers challenged by Clostridium perfringens over a 21-d period. 2. Using a 5 × 2 factorial arrangement of treatments, 800 1-d-old male Cobb 500 broilers were used to study the effects of feed additives (without additive or with zinc bacitracin, B. subtilis, YCW, and the combination of B. subtilis and YCW), pathogen challenge (without or with Clostridium perfringens challenge), and their interactive effects. 3. C. perfringens infection increased intestinal lesions scores, damaged intestinal histomorphology, increased serum endotoxin concentration, cytokine mRNA expression and intestinal population of C. perfringens and Escherichia coli and decreased ileal bifidobacteria numbers. The 4 additives decreased serum endotoxin. Zinc bacitracin tended to decrease cytokine mRNA expression and the intestinal number of C. perfringens and E. coli. B. subtilis, YCW and their combination increased cytokine mRNA expression. B. subtilis and YCW decreased the number of C. perfringens and E. coli in the ileum, and their combination decreased pathogens numbers in the ileum and caecum. 4. In conclusion, B. subtilis, YCW and their combination improved the intestinal health of NE-infected broilers, and could be potential alternatives to antibiotics.

Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis Propriedades adesivas de uma estrutura externa de Clostridium perfringens tipo A isolada de leitões com enterite catarral

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Elizabeth Pelosi Teixeira

1999-07-01

Full Text Available One strain (S32 of Clostridium perfringens type A was isolated from a case of catarrhal enteritis of piglets. This strain was able to adhere to HeLa cells showing an adherence index (AI of 25.15 ± 1.26 (mean ± 1 standard error of the mean. Treatment of the bacterial cells with trypsin (0.25mg/ml decreased in 70%-80% the AI and metaperiodate (10mg/ml abolished completely the adherence, suggesting that the structure responsible for this phenomenon was probably a glycoprotein. Heating of bacterial suspensions (100ºC/5 min before carrying out the adhesion test decreased the AI rendering it equal to the negative controls. Rabbit homologous S32 antiserum inhibited the adherence up to dilutions of 1: 640, at least. The piglet ileal loop assay, carried out with strains S32 and Jab-1 (negative control demonstrated that the strain S32 was able to adhere to the intestinal epithelial cells when examined after Gram staining. Transmission electron microcopy (TEM demonstrated that S32 strain displayed a loose fibrillar material not seen with Jab-1. Stabilization of the bacterial cells with homologous antiserum of strain S32, followed by staining with rhuteniun red, revealed loose long fibrillar material on the outer surface of the cells, that sometimes could be seen spreading out from the cells and linking bacterial cells. The question whether this structure might be an adhesin for this strain of Cl. perfringes type A, perhaps playing a role in the pathogenesis of the catarrhal enteritis of piglets, is dependent on further studies.Uma amostra (S32 de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitões. Esta amostra foi capaz de aderir a células HeLa mostrando um índice de adesão (AI de 25,15 ± 1,26 (media ± 1 erro padrão da media. Tratamento das células bacterianas com tripsina (0,25mg/ml diminuiu 70%-80% e metaperiodato (10mg/ml aboliu significantemente a adesão, sugerindo que a estrutura responsável por esta

A Quantitative Electrochemiluminescence Assay for Clostridium perfringens alpha toxin

National Research Council Canada - National Science Library

Merrill, Gerald A; Rivera, Victor R; Neal, Dwayne D; Young, Charles; Poli, Mark A

2006-01-01

.... Biotinylated antibodies to C. perfringens alpha toxin bound to streptavidin paramagnetic beads specifically immunoadsorbed soluble sample alpha toxin which subsequently selectively immunoadsorbed ruthenium (Ru...

Effect of dietary mannan oligosaccharide from Saccharomyces cerevisiae on live performance of broilers under Clostridium perfringens challenge

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Alaeldein M. Abudabos

2013-04-01

Full Text Available A 30-day broiler cage trial was conducted to evaluate the effect of dietary mannan oligosaccharide (MOS from one commercial product (SAF-Mannan on growth parameters, gut health and control pathogen colonization of broilers under Clostridium perfringens (C. perfringens challenge. One hundred, 0-day old male Ross 308 broilers were allocated in 4 experimental treatments for 30 days. The four dietary treatments were T1, standard broiler basal diets without any medication as a control (+CONT; T2, basal diets as in T1 plus C. perfringens challenge (-CONT; T3, enramycin 0.1 g/kg of feed plus C. perfringens challenge (ENRA; T4, SAF-Mannan at 0.5 g/kg in starter and finisher diets plus C. perfringens challenge (SAF. Overall, feed conversion ratio (FCR and body weight gain (BWG in treatments ENRA and SAF were significantly better (P<0.01 than the –CONT treatment, whereas treatment +CONT was intermediate and not different from SAF. Feed intake (FI was not influenced by treatment. SAF-Mannan supplementation was able to lower the ileal C. perfringens count as compared to all other treatments (P<0.05. The changes in C. perfringens count appear in parallel to observed improvement in the cumulative FCR.  The results from this study clearly indicated that SAF-Mannan could act as a replacement for antimicrobial growth promoters in broilers (AGPs. SAF-Mannan level of 0.05% was enough to achieve a response competitive with that of the antibiotic.

Predicting outgrowth and inactivation of Clostridium perfringens in meat products during low temperature long time heat treatment

DEFF Research Database (Denmark)

Duan, Zhi; Hansen, Terese Holst; Hansen, Tina Beck

2016-01-01

With low temperature long time (LTLT) cooking it can take hours for meat to reach a final core temperature above 53 °C and germination followed by growth of Clostridium perfringens is a concern. Available and new growth data in meats including 154 lag times (tlag), 224 maximum specific growth rates...... (μmax) and 25 maximum population densities (Nmax) were used to developed a model to predict growth of C. perfringens during the coming-up time of LTLT cooking. New data were generate in 26 challenge tests with chicken (pH 6.8) and pork (pH 5.6) at two different slowly increasing temperature (SIT...... the SIT profiles. Similar results were found for non-heated and heated spores in chicken, whereas in pork C. perfringens 790-94 increased less than 1 log CFU/g. At 53 °C C. perfringens 790-94 was log-linearly inactivated. Observed and predicted concentrations of C. perfringens, at the time when 53 °C (log...

CodY Promotes Sporulation and Enterotoxin Production by Clostridium perfringens Type A Strain SM101.

Science.gov (United States)

Li, Jihong; Freedman, John C; Evans, Daniel R; McClane, Bruce A

2017-03-01

Clostridium perfringens type D strains cause enterotoxemia and enteritis in livestock via epsilon toxin production. In type D strain CN3718, CodY was previously shown to increase the level of epsilon toxin production and repress sporulation. C. perfringens type A strains producing C. perfringens enterotoxin (CPE) cause human food poisoning and antibiotic-associated diarrhea. Sporulation is critical for C. perfringens type A food poisoning since spores contribute to transmission and resistance in the harsh food environment and sporulation is essential for CPE production. Therefore, the current study asked whether CodY also regulates sporulation and CPE production in SM101, a derivative of C. perfringens type A food-poisoning strain NCTC8798. An isogenic codY -null mutant of SM101 showed decreased levels of spore formation, along with lower levels of CPE production. A complemented strain recovered wild-type levels of both sporulation and CPE production. When this result was coupled with the earlier results obtained with CN3718, it became apparent that CodY regulation of sporulation varies among different C. perfringens strains. Results from quantitative reverse transcriptase PCR analysis clearly demonstrated that, during sporulation, codY transcript levels remained high in SM101 but rapidly declined in CN3718. In addition, abrB gene expression patterns varied significantly between codY -null mutants of SM101 and CN3718. Compared to the levels in their wild-type parents, the level of abrB gene expression decreased in the CN3718 codY -null mutant strain but significantly increased in the SM101 codY -null mutant strain, demonstrating CodY-dependent regulation differences in abrB expression between these two strains. This difference appears to be important since overexpression of the abrB gene in SM101 reduced the levels of sporulation and enterotoxin production, supporting the involvement of AbrB repression in regulating C. perfringens sporulation. Copyright © 2017

Produção e caracterização de anticorpos monoclonais contra toxina épsilon de Clostridium perfringens Tipo D Production and characterization of monoclonal antibodies against Clostridium perfringens Type D epsilon toxin

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Theonys Diógenes Freitas

2009-02-01

Full Text Available Clostridium perfringens tipo D é o agente etiológico da enterotoxemia em ruminantes, causada pela toxina épsilon e caracterizada por edema cardíaco, pulmonar, renal e cerebral. Anticorpos monoclonais contra toxina épsilon de C. perfringens tipo D foram produzidos a partir da fusão da linhagen de mieloma P3-X63-Ag8 653 com células do baço de camundongos Balb/c imunizados com o toxóide épsilon. Seis linhagens de híbridos secretores de anticorpos monoclonais das classes e IgM e IgG foram estabelecidas.Clostridium perfringens type D is the aetiological agent of enterotoxemia in ruminants. The disease is caused by epsilon toxin characterized by cardiac, pulmonary, kidney and brain edema. Monoclonal antibodies were produced by using myeloma cell line P3-X63-Ag8 653 fused with spleen cells from Balb/c mice, immunized with epsilon toxoid of C. perfringens type D. Six hybrids were established secreting monoclonal antibodies of the IgM class and IgG3 subclass.

The impact of various browse feeds with different tannin content on the fecal shedding of Clostridium perfringens in West African dwarf sheep.

Science.gov (United States)

Aschfalk, A; Müller, W; Drochner, W

2000-01-01

In 1994 and 1995 leaves from eight browse feeds, containing tannins in different amounts (BF), were fed to West African Dwarf Sheep in Benin to evaluate their impact on Clostridium perfringens in the intestinal tract. An inhibitory impact of various BF on the growth of C. perfringens was assessed in in-vitro assays before, and thus a potential use of these leaves as a preventive diet against C. perfringens enterotoxemia in small ruminants was assumed. Surprisingly, an inhibitory impact of the BF on the shedding of C. perfringens in the feces of West African Dwarf Sheep could not be shown in seven of the eight BF examined. However, the pattern of inhibition of unlike C. perfringens toxovars may differ and a selective inhibitory impact of the BF Dialium guineense on C. perfringens toxovar D may be assumed.

Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones.

Science.gov (United States)

Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

2012-10-21

A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved with antibiotic therapy Choledocholithiasis should be considered as a source of clostridium perfringens bacteremia especially in the setting of elevated liver enzymes with cholestatic pattern.

Comparative transcriptome analysis by RNAseq of necrotic enteritis Clostridium perfringens during in vivo colonization and in vitro conditions.

Science.gov (United States)

Parreira, Valeria R; Russell, Kay; Athanasiadou, Spiridoula; Prescott, John F

2016-08-12

Necrotic enteritis (NE) caused by netB-positive type A Clostridium perfringens is an important bacterial disease of poultry. Through its complex regulatory system, C. perfringens orchestrates the expression of a collection of toxins and extracellular enzymes that are crucial for the development of the disease; environmental conditions play an important role in their regulation. In this study, and for the first time, global transcriptomic analysis was performed on ligated intestinal loops in chickens colonized with a netB-positive C. perfringens strain, as well as the same strain propagated in vitro under various nutritional and environmental conditions. Analysis of the respective pathogen transcriptomes revealed up to 673 genes that were significantly expressed in vivo. Gene expression profiles in vivo were most similar to those of C. perfringens grown in nutritionally-deprived conditions. Taken together, our results suggest a bacterial transcriptome responses to the early stages of adaptation, and colonization of, the chicken intestine. Our work also reveals how netB-positive C. perfringens reacts to different environmental conditions including those in the chicken intestine.

Calcium Montmorillonite-based dietary supplement attenuates Necrotic Enteritis induced by Eimeria maxima and Clostridium perfringens in broilers

Science.gov (United States)

We provide the first description of Dietary Supplement of sorbent minerals attenuates Necrotic Enteritis Induced by Eimeria maxima and Clostridium perfringens in Broilers. Necrotic enteritis (NE) is a poultry disease caused by Clostridium perfringens and characterized by severe intestinal necrosis....

Mode of action of plectasin-derived peptides against gas gangrene-associated Clostridium perfringens type A.

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Xueling Zheng

Full Text Available NZ2114 and MP1102 are novel plectasin-derived peptides with potent activity against Gram-positive bacteria. The antibacterial characteristics and mechanism of NZ2114 and MP1102 against gas gangrene-associated Clostridium perfringens were studied for the first time. The minimal inhibitory concentration and minimal bactericidal concentration of NZ2114 and MP1102 against resistant C. perfringens type A strain CVCC 46 were 0.91 μM. Based on the fractional inhibitory concentration index (FICI result, an additive or synergic effect was observed between NZ2114 (FICI = 0.5~0.75 or MP1102 (FICI = 0.375~1.0 and antibiotics. The flow cytometry, scanning and transmission electron microscopy analysis showed that both NZ2114 and MP1102 induced obviously membrane damage, such as the leakage of cellular materials, partial disappearance of the cell membrane and membrane peeling, as well as retracting cytoplasm and ghost cell. The gel retardation and circular dichroism (CD detection showed that NZ2114 and MP1102 could bind to C. perfringens genomic DNA and change the DNA conformation. Moreover, NZ2114 also interfered with the double helix and unwind the genomic DNA. The cell cycle analysis showed that C. perfringens CVCC 46 cells exposed to NZ2114 and MP1102 were arrested at the phase I. These data indicated that both NZ2114 and MP1102 have potential as new antimicrobial agents for gas gangrene infection resulting from resistant C. perfringens.

Inactivation of Clostridium perfringens spores adhered onto stainless steel surface by agents used in a clean-in-place procedure.

Science.gov (United States)

Alzubeidi, Yasmeen S; Udompijitkul, Pathima; Talukdar, Prabhat K; Sarker, Mahfuzur R

2018-07-20

Enterotoxigenic Clostridium perfringens, a leading foodborne pathogen can be cross-contaminated from food processing stainless steel (SS) surfaces to the finished food products. This is mostly due to the high resistance of C. perfringens spores adhered onto SS surfaces to various disinfectants commonly used in food industries. In this study, we aimed to investigate the survivability and adherence of C. perfringens spores onto SS surfaces and then validate the effectiveness of a simulated Clean-in-Place (CIP) regime on inactivation of spores adhered onto SS surfaces. Our results demonstrated that, 1) C. perfringens spores adhered firmly onto SS surfaces and survived for at-least 48 h, unlike their vegetative cells who died within 30 min, after aerobic incubation at refrigerated and ambient temperatures; 2) Spores exhibited higher levels of hydrophobicity than vegetative cells, suggesting a correlation between cell surface hydrophobicity and adhesion to solid surfaces; 3) Intact spores were more hydrophobic than the decoated spores, suggesting a positive role of spore coat components on spores' hydrophobicity and thus adhesion onto SS surfaces; and finally 4) The CIP regime (NaOH + HNO 3 ) successfully inactivated C. perfringens spores adhered onto SS surfaces, and most of the effect of CIP regime appeared to be due to the NaOH. Collectively, our current findings may well contribute towards developing a strategy to control cross-contamination of C. perfringens spores into food products, which should help reducing the risk of C. perfringens-associated food poisoning outbreaks. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

1996-05-01

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

The mycotoxin deoxynivalenol predisposes for the development of Clostridium perfringens-induced necrotic enteritis in broiler chickens.

Science.gov (United States)

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

2014-01-01

Both mycotoxin contamination of feed and Clostridium perfringens-induced necrotic enteritis have an increasing global economic impact on poultry production. Especially the Fusarium mycotoxin deoxynivalenol (DON) is a common feed contaminant. This study aimed at examining the predisposing effect of DON on the development of necrotic enteritis in broiler chickens. An experimental Clostridium perfringens infection study revealed that DON, at a contamination level of 3,000 to 4,000 µg/kg feed, increased the percentage of birds with subclinical necrotic enteritis from 20±2.6% to 47±3.0% (Peffect on in vitro growth, alpha toxin production and netB toxin transcription of Clostridium perfringens. In conclusion, feed contamination with DON at concentrations below the European maximum guidance level of 5,000 µg/kg feed, is a predisposing factor for the development of necrotic enteritis in broilers. These results are associated with a negative effect of DON on the intestinal barrier function and increased intestinal protein availability, which may stimulate growth and toxin production of Clostridium perfringens.

Structural and biochemical analyses of a Clostridium perfringens sortase D transpeptidase

Energy Technology Data Exchange (ETDEWEB)

Suryadinata, Randy, E-mail: randy.suryadinata@csiro.au; Seabrook, Shane A.; Adams, Timothy E.; Nuttall, Stewart D.; Peat, Thomas S., E-mail: randy.suryadinata@csiro.au [Commonwealth Scientific and Industrial Research Organisation, 343 Royal Parade, Parkville, Victoria 3052 (Australia)

2015-06-30

The structure of C. perfringens sortase D was determined at 1.99 Å resolution. Comparative biochemical and structural analyses revealed that this transpeptidase may represent a new subclass of the sortase D family. The assembly and anchorage of various pathogenic proteins on the surface of Gram-positive bacteria is mediated by the sortase family of enzymes. These cysteine transpeptidases catalyze a unique sorting signal motif located at the C-terminus of their target substrate and promote the covalent attachment of these proteins onto an amino nucleophile located on another protein or on the bacterial cell wall. Each of the six distinct classes of sortases displays a unique biological role, with sequential activation of multiple sortases often observed in many Gram-positive bacteria to decorate their peptidoglycans. Less is known about the members of the class D family of sortases (SrtD), but they have a suggested role in spore formation in an oxygen-limiting environment. Here, the crystal structure of the SrtD enzyme from Clostridium perfringens was determined at 1.99 Å resolution. Comparative analysis of the C. perfringens SrtD structure reveals the typical eight-stranded β-barrel fold observed in all other known sortases, along with the conserved catalytic triad consisting of cysteine, histidine and arginine residues. Biochemical approaches further reveal the specifics of the SrtD catalytic activity in vitro, with a significant preference for the LPQTGS sorting motif. Additionally, the catalytic activity of SrtD is most efficient at 316 K and can be further improved in the presence of magnesium cations. Since C. perfringens spores are heat-resistant and lead to foodborne illnesses, characterization of the spore-promoting sortase SrtD may lead to the development of new antimicrobial agents.

Mechanisms of Action and Cell Death Associated with Clostridium perfringens Toxins

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Mauricio A. Navarro

2018-05-01

Full Text Available Clostridium perfringens uses its large arsenal of protein toxins to produce histotoxic, neurologic and intestinal infections in humans and animals. The major toxins involved in diseases are alpha (CPA, beta (CPB, epsilon (ETX, iota (ITX, enterotoxin (CPE, and necrotic B-like (NetB toxins. CPA is the main virulence factor involved in gas gangrene in humans, whereas its role in animal diseases is limited and controversial. CPB is responsible for necrotizing enteritis and enterotoxemia, mostly in neonatal individuals of many animal species, including humans. ETX is the main toxin involved in enterotoxemia of sheep and goats. ITX has been implicated in cases of enteritis in rabbits and other animal species; however, its specific role in causing disease has not been proved. CPE is responsible for human food-poisoning and non-foodborne C. perfringens-mediated diarrhea. NetB is the cause of necrotic enteritis in chickens. In most cases, host–toxin interaction starts on the plasma membrane of target cells via specific receptors, resulting in the activation of intracellular pathways with a variety of effects, commonly including cell death. In general, the molecular mechanisms of cell death associated with C. perfringens toxins involve features of apoptosis, necrosis and/or necroptosis.

Necrotizing Enterocolitis in Preterm Pigs Is Associated with Increased Density of Intestinal Mucosa-Associated Bacteria Including Clostridium perfringens

DEFF Research Database (Denmark)

Støy, Ann Cathrine Findal; Mølbak, Lars; Delègue, Camilla Lindholm

2015-01-01

correlates with NEC severity in preterm pigs and that in vitro infection with increasing densities of Clostridium perfringens, which has been associated with NEC in preterm infants, would lead to a transcriptional response related to the inflammatory conditions of NEC. Methods: First, we determined...... the density of total bacteria and C. perfringens in the distal small intestinal mucosa of 58 NEC and healthy preterm pigs using quantitative PCR. Next, we analyzed in IPEC-J2 cells the effect of different infection densities of C. perfringens type A on the expression of genes related to intestinal function...

Differential responses of cecal microbiota to fishmeal, Eimeria and Clostridium perfringens in a necrotic enteritis challenge model in chickens.

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Dragana Stanley

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

Evaluation of PCR and DNA hybridization protocols for detection of viable enterotoxigenic Clostridium perfringens in irradiated beef

International Nuclear Information System (INIS)

Baez, L.A.; Juneja, V.K.; Thayer, D.W.; Sackitey, S.

1997-01-01

The sensitivity of DNA hybridization and polymerase chain reaction (PCR), was evaluated in irradiated cooked and raw beef samples. A membrane-based colony hybridization assay and a PCR protocol, both with specificity for the enterotoxin A gene of Clostridium perfringens, were compared with viable plate counts. The results of the colony hybridization procedure were in agreement with viable plate counts for detection and enumeration of enterotoxigenic C. perfringens. The PCR procedure combined a 4 h enrichment followed by a nucleic acid extraction step and assessed the amplification of 183 and 750 base pair enterotoxin gene targets. Detection of C. perfringens by PCR did not show a reliable correlation with viable plate counts or the colony hybridization assay. C. perfringens killed by irradiation were not detected by the plate count or colony hybridization methods; however, killed cells were detected with the PCR technique. By relying on the growth of viable cells for detection and/or enumeration, the colony hybridization and plate count methods provided a direct correlation with the presence of viable bacteria

Clostridium perfringens challenge and dietary fat type modifies performance, microbiota composition and histomorphology of the broiler chicken gastrointestinal tract

DEFF Research Database (Denmark)

Josefiak, Damian; Swiatkiewicz, S; Kieronczyk, B

2016-01-01

Belastung mit Clostridium perfringens und Futterfettquelle modifizieren die Leistung, die Zusammensetzung der Microbiota und die Histomorphologie des Verdauungstraktes beim Broiler......Belastung mit Clostridium perfringens und Futterfettquelle modifizieren die Leistung, die Zusammensetzung der Microbiota und die Histomorphologie des Verdauungstraktes beim Broiler...

Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

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Marcela Radaelli

2016-06-01

Full Text Available Abstract Despite recent advances in food production technology, food-borne diseases (FBD remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil, Rosmarinus officinalis L. (rosemary, Origanum majorana L. (marjoram, Mentha × piperita L. var. Piperita (peppermint, Thymus vulgaris L. (thyme and Pimpinella anisum L. (anise against C. perfringens strain A. Chemical compositions of the oils were determined by GC–MS (gas chromatography–mass spectrometry. The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC using the microdilution method. Minimum inhibitory concentration values were 1.25 mg mL-1 for thyme, 5.0 mg mL-1 for basil and marjoram, and 10 mg mL-1 for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens.

Science.gov (United States)

Radaelli, Marcela; da Silva, Bárbara Parraga; Weidlich, Luciana; Hoehne, Lucélia; Flach, Adriana; da Costa, Luiz Antonio Mendonça Alves; Ethur, Eduardo Miranda

2016-01-01

Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC-MS (gas chromatography-mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25mgmL(-1) for thyme, 5.0mgmL(-1) for basil and marjoram, and 10mgmL(-1) for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Bayesian modeling of Clostridium perfringens growth in beef-in-sauce products.

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Jaloustre, S; Cornu, M; Morelli, E; Noël, V; Delignette-Muller, M L

2011-04-01

Models on Clostridium perfringens growth which have been published to date have all been deterministic. A probabilistic model describing growth under non-isothermal conditions was thus proposed for predicting C. perfringens growth in beef-in-sauce products cooked and distributed in a French hospital. Model parameters were estimated from different types of data from various studies. A Bayesian approach was proposed to model the overall uncertainty regarding parameters and potential variability on the 'work to be done' (h(0)) during the germination, outgrowth and lag phase. Three models which differed according to their description of this parameter h(0) were tested. The model with inter-curve variability on h(0) was found to be the best one, on the basis of goodness-of-fit assessment and validation with literature data on results obtained under non-isothermal conditions. This model was used in two-dimensional Monte Carlo simulations to predict C. perfringens growth throughout the preparation of beef-in-sauce products, using temperature profiles recorded in a hospital kitchen. The median predicted growth was 7.8×10(-2) log(10) cfu·g(-1) (95% credibility interval [2.4×10(-2), 0.8]) despite the fact that for more than 50% of the registered temperature profiles cooling steps were longer than those required by French regulations. Copyright © 2010 Elsevier Ltd. All rights reserved.

Occurrence of Clostridium perfringens in sausages sold in Meknes ...

African Journals Online (AJOL)

In Morocco, the consumption of meat products has experienced a sharp increase in recent years despite the presence of pathogenic bacteria due to hygiene failure. The present study was designed to determine the prevalence of Clostridium perfringens in sausages sold in Meknes city (Morocco) and to study the different ...

Clostridium perfringens em rações e águas fornecidos a frangos de corte em granjas avícolas do interior paulista: Brasil Clostridium perfringens search in water and ration used in the raising of broiler in sheds of São Paulo State: Brazil

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Rubén Pablo Schocken-Iturrino

2010-02-01

Full Text Available Através de métodos bacteriológicos convencionais, avaliou-se a contaminação por Clostridium perfringens na ração e água utilizadas na alimentação e dessedentação de frangos de corte em diferentes regiões avícolas do interior paulista. C. perfringens esteve presente em 42 e 30% das amostras de ração e águas analisadas, respectivamente. As médias das contagens foram 6,7 x 10-2UFC mL para as amostras de água e 3,69 x 10-2UFC g para as de rações. As altas freqüências e contagens de C. perfringens verificadas nas rações e nas águas podem estar associadas à falta de higiene geral na manipulação e armazenamento dos mesmos. Sugere-se o monitoramento periódico da presença de C. perfringens nestas fontes, com a finalidade de evitar tal patógeno, em vista que o mesmo pode causar um surto de enterite necrótica levando, assim a grandes prejuízos na produção avícola.Through conventional bacteriological methods, the contamination by Clostridium perfringens was evaluated in the ration and water used in the feeding of poultry chickens from different region of the interior from São Paulo. C. perfringens was present in 42 and 30% of the ration samples and waters analyzed respectively. The averages of the countings were 6.7 x 10-2CFU mL for the samples of water and 3.69 x 10-2CFU g for rations. The high frequencies and countings of C. perfringens verified in the rations and in the waters may be associated to the lack of general hygiene in the manipulation and storage of the same ones. These suggests a periodic monitoration of the presence of C. perfringens in these sources, with the purpose of avoiding such pathogen, in view that this organism can provoke an outbreak of necrotic enteritis, and cause great damages in the poultry production.

Effects of Clostridium perfringens iota toxin in the small intestine of mice.

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Redondo, Leandro M; Redondo, Enzo A; Dailoff, Gabriela C; Leiva, Carlos L; Díaz-Carrasco, Juan M; Bruzzone, Octavio A; Cangelosi, Adriana; Geoghegan, Patricia; Fernandez-Miyakawa, Mariano E

2017-12-01

Iota toxin is a binary toxin solely produced by Clostridium perfringens type E strains, and is structurally related to CDT from C. difficile and CST from C. spiroforme. As type E causes hemorrhagic enteritis in cattle, it is usually assumed that associated diseases are mediated by iota toxin, although evidence in this regard has not been provided. In the present report, iota toxin intestinal effects were evaluated in vivo using a mouse model. Histological damage was observed in ileal loops treated with purified iota toxin after 4 h of incubation. Luminal iota toxin induced fluid accumulation in the small intestine in a dose dependent manner, as determined by the enteropooling and the intestinal loop assays. None of these changes were observed in the large intestine. These results suggest that C. perfringens iota toxin alters intestinal permeability, predominantly by inducing necrosis and degenerative changes in the mucosal epithelium of the small intestine, as well as changes in intestinal motility. The obtained results suggest a central role for iota toxin in the pathogenesis of C. perfringens type E hemorrhagic enteritis, and contribute to remark the importance of clostridial binary toxins in digestive diseases. Published by Elsevier Ltd.

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

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Józefiak, D; Kierończyk, B; Rawski, M; Hejdysz, M; Rutkowski, A; Engberg, R M; Højberg, O

2014-06-01

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

Alterações fisiológicas do sistema nervoso central de rã pelas toxinas de Cl. perfringens, Cl. oedematiens e Cl. septicum

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Genésio Pacheco

1947-09-01

Full Text Available The authors carried on experiences in order to confirm the neurotoxic theory of gas gangrene explained by Pacheco & Costa, uning preparations of isolated cord-posterior train of Leptodactylus ocellatus as described by OZORIO DE ALMEIDA & Cols. Frogs were intoxicated 3 days before the test with parcially purified toxins of Cl. perfringens, Cl. oedematiens and Cl. septicum. The intoxication produced a shortening of spinal reflexes duration time of such preparations, showing a typical alteration of the reflex activity of the spinal cord.

9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.

Science.gov (United States)

2010-01-01

... Clostridium perfringens Type D. Each serial shall be tested as provided in this section. Any serial found... following words and terms shall mean: (i) International antitoxin unit. (I.U.) That quantity of Epsilon... 0.25 gram of sodium chloride in each 100 ml of distilled water; adjusting the pH to 7.2; autoclaving...

Modeling growth of Clostridium perfringens in pea soup during cooling

NARCIS (Netherlands)

Jong, de A.E.I.; Beumer, R.R.; Zwietering, M.H.

2005-01-01

Clostridium perfringens is a pathogen that mainly causes food poisoning outbreaks when large quantities of food are prepared. Therefore, a model was developed to predict the effect of different cooling procedures on the growth of this pathogen during cooling of food: Dutch pea soup. First, a growth

9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.

Science.gov (United States)

2010-01-01

... Clostridium perfringens Type C. Each serial shall be tested as provided in this section. Any serial found... following words and terms shall mean: (i) International antitoxin unit. (I.U.) That quantity of Beta... chloride in each 100 ml of distilled water; adjusting the pH to 7.2; autoclaving at 250 °F. for 25 minutes...

Embryonated chicken eggs as an alternative model for mixed Clostridium perfringens and Eimeria tenella infection in chickens.

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Alnassan, Alaa Aldin; Shehata, Awad Ali; Kotsch, Marianne; Lendner, Matthias; Daugschies, Arwid; Bangoura, Berit

2013-06-01

The chorioallantoic membrane (CAM) of chicken embryo eggs is a suitable model for viral and bacterial infections. In the present study, a new approach for testing the pathogenesis and virulence of Clostridium perfringens and Eimeria tenella dual infections as a model using the CAM of embryonated chicken eggs was developed. For this purpose, 24 specific pathogen-free (SPF) embryonated chicken eggs were divided into four groups (n = 6) and designated group E, group CP, group CPE, and NC. Sporozoites of E. tenella (20,000 sporozoites) were inoculated into 10-day-old embryonated SPF chicken eggs (groups E and CPE) via allantoic sac route. At 15-day-old, eggs of groups CP and CPE were infected with 10 (4)  cfu C. perfringens via the same route. Assessment of pathogenicity was assessed using gross and histopathological lesions. Embryo mortality reached 17 % after mono-infection with C. perfringens and/or E. tenella and 50 % in the mixed-infected group. Lesions in the CAMs were most numerous and most severe in co-infected eggs (group CPE), reaching the maximum score of 3 in 50 % of the inoculated eggs (P < 0.01). In Eimeria spp.-infected eggs (group E), lesions of score were between 1 and 2. Mono-infection with C. perfringens did not lead to a significant occurrence of lesions. Histopathological investigations of the CAM revealed clusters of Gram-positive bacteria, infiltration with leukocytes, lymphocytes, and developmental stages of E. tenella in the co-infected group. These data suggest that embryonated eggs could be an in ovo model for studying the pathogenesis of mixed infection with Eimeria and C. perfringens.

Alphitobius diaperinus spp como veiculador de Clostridium perfringens em granjas avícolas do interior paulista - Brasil Alphitobius diaperinus spp as a vector of Clostridium perfringens in broiler houses in the state of São Paulo - Brazil

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Juliano Vittori

2007-06-01

Full Text Available O besouro Alphitobius diaperinus spp (cascudinho é visto como uma importante praga da avicultura mundial. Por suas características comportamentais e hábitos biológicos que dificultam seu controle, é considerado um vetor de agentes patogênicos. O objetivo desta pesquisa foi investigar o cascudinho como possível vetor de Clostridium perfringens em granjas avícolas industriais, localizadas em diferentes regiões do interior Paulista. Através de métodos bacteriológicos convencionais, em 40 amostras analisadas, foram encontradas contagens significativas de Clostridium perfringens em todas elas. A partir dos resultados obtidos, pôde-se demonstrar o potencial deste inseto como vetor do agente responsável pela enterite necrótica.The Alphitobius diaperinus spp (lesser mealworm is considered an important world poultry plague. Due to its behavior characteristics and biological habits that make its control difficult it is considered a vector of pathogenic agents. The objective of this research was to investigate the little mealworm as possible vector of Clostridium perfringens in broiler houses, located in different parts of the state of São Paulo. Through conventional bacteriological methods, 40 samples of little mealworm collected were analyzed. Clostridium perfringens was found in all of the samples and the potential of this insect as vector of the necrotic enteritis was demonstrated.

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

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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 iden...

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

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Miseon Park

2014-01-01

Full Text Available 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.

Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis.

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Wu, Yuanyuan; Shao, Yujing; Song, Bochen; Zhen, Wenrui; Wang, Zhong; Guo, Yuming; Shahid, Muhammad Suhaib; Nie, Wei

2018-01-01

The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis (NE) due to Clostridium perfringens . This study was conducted to investigate the effects of feeding Bacillus coagulans on the growth performance and gut health of broiler chickens with C. perfringens -induced NE. Two hundred and forty 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two dietary B. coagulans levels (0 or 4 × 10 9  CFU/kg of diet) and two disease challenge statuses (control or NE challenged). NE-induced reduction in body weight gain was relieved by the addition of B. coagulans into broiler diets compared with the NE-infected birds. NE infection damaged intestinal morphological structure, promoted intestinal C. perfringens growth and liver invasion, and enhanced anti- C. perfringens specific sIgA concentrations in the gut and specific IgG levels in serum compared with the uninfected birds. NE infection significantly ( P  coagulans showed a significant ( P  coagulans improved intestinal barrier structure, further increased specific sIgA levels and alkaline phosphatase (IAP) activity in the jejunum, enhanced the expression of jejunum lysozyme mRNA, and inhibited the growth, colonization, and invasion of C. perfringens ; in contrast, it reduced serum-specific IgG concentrations and jejunum IFN-γ mRNA levels. These results indicated that dietary B. coagulans supplementation appeared to be effective in preventing the occurrence and reducing the severity of C. perfringens -induced NE in broiler chickens.

In vitro Clostridium perfringens and Escherichia coli toxin adsorption of Varium

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Enteric disease agents, such as Clostridium perfringens and Escherichia coli, produce detrimental biotoxins that cause significant economic loss annually in the poultry industry. The objective of this study was to determine the in vitro biotoxin adsorption capability of Varium. An enzyme-linked im...

Analysis of plasmid profiling as a method for rapid differentiation of food-associated Clostridium perfringens strains.

Science.gov (United States)

Jones, M K; Iwanejko, L A; Longden, M S

1989-09-01

Plasmid analysis of over 120 strains of Clostridium perfringens, isolated during food-poisoning incidents and from animal carcasses and food constituents with no association with food poisoning, showed the potential of plasmid profiling as a means of differentiating epidemiologically related strains. On average 65% of freshly isolated strains contained one or more plasmids which could be used in the analysis. Comparison of profiles of strains from unrelated sources or unrelated strains from the same source showed a particularly wide variety of plasmid profiles. Thus the possibility that epidemiologically-unrelated strains might possess similar profiles appears to be very low in this organism. Analysis of serologically-related strains from the same source revealed similar plasmid profiles in all the plasmid-bearing strains examined. A high proportion (71%) of fresh and well-characterized food-poisoning strains possessed plasmids of 6.2 kb in size (compared with 19% of non-food-poisoning strains). The possible role of these plasmids is discussed, since the structural gene encoding the enterotoxin type A was not present on any of the plasmids in the food-poisoning strains tested.

Disruption in the cecal microbiota of chickens challenged with Clostridium perfringens and other factors was alleviated by Bacillus licheniformis supplementation.

Science.gov (United States)

Lin, Yicen; Xu, Shuai; Zeng, Dong; Ni, Xueqin; Zhou, Mengjia; Zeng, Yan; Wang, Hesong; Zhou, Yi; Zhu, Hui; Pan, Kangcheng; Li, Guangyao

2017-01-01

Clostridium perfringens can induce necrotic enteritis of chickens, which causes large economic losses every year. Bacillus licheniformis, a probiotic, can inhibit the growth of pathogenic bacteria such as Clostridium perfringens, thereby improving the health status of chickens. However, from a microbial ecology perspective, the mechanisms by which alterations to the gut microbiota improve health remain unknown. In this study, we used Illumina MiSeq sequencing to investigate the cecal microbiota of a negative control group (NC), a C. perfringens and Eimeria challenge group with fishmeal supplementation (PC), a group supplemented with fishmeal and infected with coccidia (FC), and group PC with B. licheniformis supplementation (BL). We found that the health status of C. perfringens-challenged chickens was compromised, and that B. licheniformis improved the growth of the chickens challenged with pathogens. Microbial diversity analysis and taxonomic profiling of groups NC, PC, and FC revealed a disturbed cecal microflora of the birds with C. perfringens. We also characterized the microbiota of the chickens in the BL group using several methods. Principal coordinate analysis demonstrated that, compared with group PC, the bacterial community structure of group BL was more similar to that of group NC. Linear discriminant analysis with effect size revealed less differentially represented bacterial taxa between groups BL and NC than between groups PC and NC. In addition, groups BL and NC appeared to have similar overrepresented microbial taxa (such as Bacteroides, Helicobacter, Megamonas, and Akkermansia) compared with group PC. Finally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that large differences existed between group PC and groups NC and BL. In conclusion, pre-treatment with B. licheniformis reduced the disturbance of the cecal microbiome induced by challenge with C. perfringens and other factors in broiler

Genome-wide transcriptional profiling of Clostridium perfringens SM101 during sporulation

NARCIS (Netherlands)

Xiao, Yinghua; Hijum, van Sacha A.; Abee, Tjakko; Wells-Bennik, Marjon H.

2014-01-01

In this study we focus on the identification of new genes tentatively involved in sporulation and those that influence properties of spores and their ability to germinate. To this end, the sporulation stages of C. perfringens enterotoxic strain SM101 were characterized based on morphological

Cloning in Escherichia coli of the enterotoxin gene from Clostridium perfringens type A.

Science.gov (United States)

Iwanejko, L A; Routledge, M N; Stewart, G S

1989-04-01

A 26 bp DNA probe has been constructed with minimal degeneracy to the protein sequence for Clostridium perfringens enterotoxin. The probe has been hybridized against a 6-10 kb chromosomal bank from C. perfringens 8239, prepared as a HindIII partial digest in pHG165. From this survey a clone has been identified containing a 6.8 kb DNA insert with strong hybridization to the probe. Direct plasmid sequencing has identified a translational reading frame within this clone which correlates with the known protein sequence for the type A enterotoxin. DNA sequences 5' to this open reading frame and containing the putative transcriptional control regions show areas of significant homology with regions upstream from the ATG codon of the tetanus toxin gene.

Probing Genomic Aspects of the Multi-Host Pathogen Clostridium perfringens Reveals Significant Pangenome Diversity, and a Diverse Array of Virulence Factors.

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Kiu, Raymond; Caim, Shabhonam; Alexander, Sarah; Pachori, Purnima; Hall, Lindsay J

2017-01-01

Clostridium perfringens is an important cause of animal and human infections, however information about the genetic makeup of this pathogenic bacterium is currently limited. In this study, we sought to understand and characterise the genomic variation, pangenomic diversity, and key virulence traits of 56 C. perfringens strains which included 51 public, and 5 newly sequenced and annotated genomes using Whole Genome Sequencing. Our investigation revealed that C. perfringens has an "open" pangenome comprising 11667 genes and 12.6% of core genes, identified as the most divergent single-species Gram-positive bacterial pangenome currently reported. Our computational analyses also defined C. perfringens phylogeny (16S rRNA gene) in relation to some 25 Clostridium species, with C. baratii and C. sardiniense determined to be the closest relatives. Profiling virulence-associated factors confirmed presence of well-characterised C. perfringens -associated exotoxins genes including α-toxin ( plc ), enterotoxin ( cpe ), and Perfringolysin O ( pfo or pfoA ), although interestingly there did not appear to be a close correlation with encoded toxin type and disease phenotype. Furthermore, genomic analysis indicated significant horizontal gene transfer events as defined by presence of prophage genomes, and notably absence of CRISPR defence systems in >70% (40/56) of the strains. In relation to antimicrobial resistance mechanisms, tetracycline resistance genes ( tet ) and anti-defensins genes ( mprF ) were consistently detected in silico ( tet : 75%; mprF : 100%). However, pre-antibiotic era strain genomes did not encode for tet , thus implying antimicrobial selective pressures in C. perfringens evolutionary history over the past 80 years. This study provides new genomic understanding of this genetically divergent multi-host bacterium, and further expands our knowledge on this medically and veterinary important pathogen.

Determination of enterotoxigenic Clostridium perfringens by detecting of the cpa and cpe genes in stool samples of human origin, associated to gastrointestinal disease

International Nuclear Information System (INIS)

Oropeza Barrios, Gletty

2014-01-01

A molecular methodology is provided to the Centro Nacional de Referencia de Bacteriologia (CNRB) of the Instituto Costarricense de Investigacion y Ensenanza en Nutricion y Salud. An opportune diagnosis is realized of enterotoxigenic Clostridium perfringens in stool samples of sporadic cases and cases associated to foodborne disease outbreaks. DNA extraction of the white microorganism was performed through the methodology implemented in the CNRB. The technique of polymerase chain reaction (PCR) were adapted and standardized to establish the identification of C. perfringens to species level and detection of cpe gene coding for enterotoxin. The sensitivity of the method was determined in a selective culture medium for C. perfringens (Tryptose sulfite cycloserine Agar). A detection limit of about 2,3 x 10 4 CFU/ml was reached for the cpe gene and at least 2,8 x 10 2 CFU/ml for the cpa gene. Retrospective analysis of 61 samples of diarrheal stool suspicious by C. perfringens is performed to evaluate the efficacy of the technique. Three outbreaks caused by C. perfringens were identified and a 10% of positivity in the samples were obtained analyzed during the period between July 2012-March 2014 [es

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

Science.gov (United States)

Yasugi, Mayo; Otsuka, Keisuke; Miyake, Masami

2016-10-01

Clostridium perfringens type A is a common source of food-borne illness in humans. Ingested vegetative cells sporulate in the small intestinal tract and in the process produce C. perfringens enterotoxin (CPE). Although sporulation plays a critical role in the pathogenesis of food-borne illness, the molecules triggering/inhibiting sporulation are still largely unknown. It has previously been reported by our group that sporulation is induced in C. perfringens strain NCTC8239 co-cultured with Caco-2 cells in Dulbecco's Modified Eagle Medium (DMEM). In contrast, an equivalent amount of spores was not observed when bacteria were co-cultured in Roswell Park Memorial Institute-1640 medium (RPMI). In the present study it was found that, when these two media are mixed, RPMI inhibits sporulation and CPE production induced in DMEM. When a component of RPMI was added to DMEM, it was found that calcium nitrate (Ca[NO 3 ] 2 ) significantly inhibits sporulation and CPE production. The number of spores increased when Ca(NO 3 ) 2 -deficient RPMI was used. The other nitrate salts significantly suppressed sporulation, whereas the calcium salts used did not. qPCR revealed that nitrate salts increased expression of bacterial nitrate/nitrite reductase. Furthermore, it was found that nitrite and nitric oxide suppress sporulation. In the sporulation stages, Ca(NO 3 ) 2 down-regulated the genes controlled by Spo0A, a master regulator of sporulation, but not spo0A itself. Collectively, these results indicate that nitrate salts suppress sporulation and CPE production by down-regulating Spo0A-regulated genes in C. perfringens strain NCTC8239. Nitrate reduction may be associated with inhibition of sporulation. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

Decontamination of Clostridium perfringens and Salmonella spp. in Thai Fermented Fish (Pla-ra) by Gamma Radiation

International Nuclear Information System (INIS)

Prakhongsil, P.; Phianphak, W.; Malakrong, A.; Komolamisra, C.

2014-01-01

Gamma radiation can be applied as a decontamination method to eliminate microorganisms in fermented food. In this study, samples of Thai fermented fish were evaluated for microbiological and hygienic qualities and then exposed to gamma irradiation. Prior to irradiation, Salmonella spp. and Clostridium perfringens were detected and the results were found contaminated in five samples from twenty-six of Thai fermented fish samples ; Nile tilapia fish (Oreochromisniloticus), bighead carp fish (Aristichthys nobilis) and common snakehead fish (Channa striata) using VIDAS Salmonella Easy SLM assay and standard conventional assay for C. perfringens. For detecting of living parasites helminths, fifteen samples were assayed for liver fluke (Opisthorchis viverrini) and Gnathostoma spinigerum, but neither was found. When exposed to gamma irradiation, results showed that the minimum dose of 2.70 kGy could sufficiently eliminate Salmonella spp. from fermented Nile tilapia fish (Oreochromis nioloticus), whereas a higher dose of 6.16 kGy was required to reduce C. perfringens from130 CFU/g and 10 CFU/g to less than 10 CFU/g in fermented Nile tilapia fish and common snakehead fish (Channa striata) fish.

Recombinant Alpha, Beta, and Epsilon Toxins of Clostridium perfringens: Production Strategies and Applications as Veterinary Vaccines

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Marcos Roberto A. Ferreira

2016-11-01

Full Text Available Clostridium perfringens is a spore-forming, commensal, ubiquitous bacterium that is present in the gastrointestinal tract of healthy humans and animals. This bacterium produces up to 18 toxins. The species is classified into five toxinotypes (A–E according to the toxins that the bacterium produces: alpha, beta, epsilon, or iota. Each of these toxinotypes is associated with myriad different, frequently fatal, illnesses that affect a range of farm animals and humans. Alpha, beta, and epsilon toxins are the main causes of disease. Vaccinations that generate neutralizing antibodies are the most common prophylactic measures that are currently in use. These vaccines consist of toxoids that are obtained from C. perfringens cultures. Recombinant vaccines offer several advantages over conventional toxoids, especially in terms of the production process. As such, they are steadily gaining ground as a promising vaccination solution. This review discusses the main strategies that are currently used to produce recombinant vaccines containing alpha, beta, and epsilon toxins of C. perfringens, as well as the potential application of these molecules as vaccines for mammalian livestock animals.

Mucin gene mRNA levels in broilers challenged with eimeria and/or Clostridium perfringens.

Science.gov (United States)

Kitessa, Soressa M; Nattrass, Gregory S; Forder, Rebecca E A; McGrice, Hayley A; Wu, Shu-Biao; Hughes, Robert J

2014-09-01

The effects of Eimeria (EM) and Clostridium perfringens (CP) challenges on the mRNA levels of genes involved in mucin (Muc) synthesis (Muc2, Muc5ac, Muc13, and trefoil family factor-2 [TFF2]), inflammation (tumor necrosis factor alpha [TNF-alpha] and interleukin-18 [IL-18]), and metabolic processes (cluster of differentiation [CD]36) in the jejunum of broilers were investigated. Two parallel experiments involving 1) EM challenge and 2) EM and CP challenges were conducted. The first experiment was a 2 X 2 study with 12 birds per treatment (N = 48) involving fishmeal substitution (25%) in the diet (FM) and EM challenge. The treatments were: Control (FM-, EM-), Fishmeal (FM+, EM-), EM challenge (FM-, EM+), and fishmeal substitution and EM challenge (FM+, EM+). The second experiment was a 2 X 2 X 2 experiment with six birds per treatment (N = 48) involving fishmeal (FM-, FM+), Eimeria (EM-, EM+), and C perfringens (CP-, CP+). In both arms of the study, male broilers were given a starter diet for the whole period of 16 days, except those assigned to FM+, where 25% of the starter ration was replaced with fishmeal from days 8 to 14. EM inoculation was performed on day 9 and CP inoculation on days 14 and 15. The EM challenge birds were euthanatized for sampling on day 13; postmortem examination and sampling for the Eimeria plus C perfringens challenge arm of the study were on day 16. In the Eimeria challenge arm of the study, fishmeal supplementation significantly suppressed the mRNA levels of TNF-alpha, TFF2, and IL-18 pre-CP inoculation but simultaneously increased the levels of Muc13 and CD36 mRNAs. Birds challenged with Eimeria exhibited increased mRNA levels of Muc13, Muc5ac, TNF-alpha, and IL-18. In the Eimeria and C. perfringens challenge arm, birds exposed to EM challenge exhibited significantly lower mRNA levels of Muc2 and CD36. The mRNA levels of CD36 were also significantly suppressed by CP challenge. Our results showed that the transcription of mucin synthesis

Probing Genomic Aspects of the Multi-Host Pathogen Clostridium perfringens Reveals Significant Pangenome Diversity, and a Diverse Array of Virulence Factors

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Raymond Kiu

2017-12-01

Full Text Available Clostridium perfringens is an important cause of animal and human infections, however information about the genetic makeup of this pathogenic bacterium is currently limited. In this study, we sought to understand and characterise the genomic variation, pangenomic diversity, and key virulence traits of 56 C. perfringens strains which included 51 public, and 5 newly sequenced and annotated genomes using Whole Genome Sequencing. Our investigation revealed that C. perfringens has an “open” pangenome comprising 11667 genes and 12.6% of core genes, identified as the most divergent single-species Gram-positive bacterial pangenome currently reported. Our computational analyses also defined C. perfringens phylogeny (16S rRNA gene in relation to some 25 Clostridium species, with C. baratii and C. sardiniense determined to be the closest relatives. Profiling virulence-associated factors confirmed presence of well-characterised C. perfringens-associated exotoxins genes including α-toxin (plc, enterotoxin (cpe, and Perfringolysin O (pfo or pfoA, although interestingly there did not appear to be a close correlation with encoded toxin type and disease phenotype. Furthermore, genomic analysis indicated significant horizontal gene transfer events as defined by presence of prophage genomes, and notably absence of CRISPR defence systems in >70% (40/56 of the strains. In relation to antimicrobial resistance mechanisms, tetracycline resistance genes (tet and anti-defensins genes (mprF were consistently detected in silico (tet: 75%; mprF: 100%. However, pre-antibiotic era strain genomes did not encode for tet, thus implying antimicrobial selective pressures in C. perfringens evolutionary history over the past 80 years. This study provides new genomic understanding of this genetically divergent multi-host bacterium, and further expands our knowledge on this medically and veterinary important pathogen.

Susceptibility of Clostridium perfringens strains from broiler chickens to antibiotics and anticoccidials.

Science.gov (United States)

Martel, A; Devriese, L A; Cauwerts, K; De Gussem, K; Decostere, A; Haesebrouck, F

2004-02-01

Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%).

Effect of a probiotic on prevention of diarrhea and Clostridium difficile and Clostridium perfringens shedding in foals

DEFF Research Database (Denmark)

Schoster, Angelika; Staempfli, H R; Abrahams, M

2015-01-01

of incidence and duration of diarrhea and fecal shedding of Clostridium perfringens and Clostridium difficile between treatment and age groups. RESULTS: The overall incidence of diarrhea was 41 of 72 (59%) and did not differ (P = 0.37) between treatment groups. Foals treated with probiotics were more likely...... of C. perfringens shedding was 55% with no difference between treatment groups (P = 0.23). The prevalence of C. difficile shedding was 11%. CONCLUSION AND CLINICAL IMPORTANCE: There was no benefit of administering a 3-week course of probiotics, but potential adverse effects were noted. Whether...

Clostridial necrotic enteritis in chicken associated with growth rate depression

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Adin Priadi

2008-03-01

Full Text Available Clostridium perfringens (C. perfringens is a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen causing necrotic enteritis. C. perfringens only causes necrotic enteritis when it transforms from non-toxin producing type to toxin producing type. The alpha toxin, (phospholipase C is believed to be a key to the occurrence of Clostridial necrotic enteritis (CNE. The best known predisposing factor is mucosal damage, caused by coccidiosis that damages the intestinal lining, making the gut susceptible to infections including C. perfringens. The purpose of this study was to observe the chicken performance in experimental CNE and field cases of CNE. Diagnosis of CNE were made by latex agglutination test, isolation and identification of the agent. Pathological and histopathological changes were also observed. Experimentally, NE could be reproduced when Eimeria sp and C. perfringens spores are inoculated in chicken. Signs of an NE are wet litter and diarrhea, and an increase in mortality is not often obvious. The depression of growth rate and feed efficiency of chicken become noticeable by week 5 because of damage to the intestine and the subsequent reduction in digestion and absorption of food. Subclinical form of CNE was also frequently found in the field, leading to significant decreases in performance. Chicken gut samples examinations revealed that subclinical form of CNE causes damage to the intestinal mucosa caused by C. perfringens leads to decreased digestion and absorption, increased feed conversion ratio and reduced weight gain. Dual infection with C. perfringens and Eimeria sp. was frequently found in field. The results of these studies provide evidence for C. perfringens as a causative bacteria for growth depression.

Necrotic enteritis locus 1 diguanylate cyclase and phosphodiesterase (cyclic-di-GMP) gene mutation attenuates virulence in an avian necrotic enteritis isolate of Clostridium perfringens.

Science.gov (United States)

Parreira, Valeria R; Ojha, Shivani; Lepp, Dion; Mehdizadeh Gohari, Iman; Zhou, Hongzhuan; Susta, Leonardo; Gong, Jianhua; Prescott, John F

2017-09-01

Necrotic enteritis (NE) caused by netB-positive strains of Clostridium perfringens is an important disease of intensively-reared broiler chickens. It is widely controlled by antibiotic use, but this practice that has come under increasing scrutiny and alternative approaches are required. As part of the search for alternative approaches over the last decade, advances have been made in understanding its pathogenesis but much remains to be understood and applied to the control of NE. The objective of this work was to assess the effect on virulence of mutation of the cyclic-di-GMP signaling genes present on the large pathogenicity locus (NELoc-1) in the tcp-encoding conjugative virulence plasmid, pNetB. For this purpose, the diguanylate cyclase (dgc) and phosphodiesterase (pde) genes were individually insertionally inactivated and the two mutants were subsequently complemented with their respective genes. Southern blotting showed that a single gene insertion was present. Mutation of either gene resulted in almost total attenuation of the mutants to cause NE in experimentally-infected broiler chickens, which was fully restored in each case by complementation of the respective mutated gene. Production of NetB-associated cytotoxicity for Leghorn male hepatoma (LMH) cells was unaffected in mutants. We conclude that the cyclic-di-GMP signaling system is important in controlling virulence in a NE C. perfringens strain and might be a target for control of the disease. Copyright © 2017 Elsevier B.V. All rights reserved.

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

OpenAIRE

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

1996-01-01

Clostridium perfringens, a marker of domestic sewage contamination, was enumerated in sediment samples obtained from the vicinity of the 106-Mile Site 1 month and 1 year after cessation of sewage disposal at this site. C. perfringens counts in sediments collected at the disposal site and from stations 26 nautical miles (ca. 48 km) and 50 nautical miles (ca. 92 km) to the southwest of the site were, in general, more than 10-fold higher than counts from an uncontaminated reference site. C. perf...

Synergistic effect of embryo vaccination with Eimeria profilin and Clostridium perfringens NetB proteins on inducing protective immunity against necrotic enteritis in broiler chickens

Science.gov (United States)

The effects of embryo vaccination with Eimeria profilin plus Clostridium perfringens NetB toxin proteins in combination with the Montanide IMS-OVO adjuvant on the chicken immune response to necrotic enteritis were investigated using an E. maxima/C. perfringens co-infection model. Eighteen-day-old br...

Detection of Different Genotypes of Clostridium perfringens in Feces of Healthy Dairy Cattle from China using Real-Time Duplex PCR Assay

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Guanghua Wang, Jizhang Zhou, Fuying Zheng, Guozhen Lin, Xiaoan Cao, Xiaowei Gong and Changqing Qiu*

2011-04-01

Full Text Available Dual-labeled fluorescence hybridization probe-based multiplex quantitative real-time polymerase chain reaction (qPCR assay was used for the detection of Clostridium perfringens toxin genes alpha (cpa, beta (cpb, iota (ia, epsilon (etx, beta2 (cpb2 and enterotoxin (cpe directly from the feces of cattle. Fecal samples from 261 lactating cattle, belonging to three dairy herds in Ningxia (China, were examined using the developed assays. The duplex qPCR assay revealed that cpa, etx, cpb2 and cpe toxin genes were detected in 176 (100%, 15 (8.5%, 142 (80.7% and 4 (2.3% of 176 PCR positive samples, respectively. The findings of this study revealed that C. perfringens beta2-toxin-producing strains were widely prevalent in lactating cows in Ningxia, possibly playing an important role in C. perfringens-associated diarrheal disease.

Adsorptive effects of di-tri-octahedral smectite on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies.

Science.gov (United States)

Lawler, Jacquelin Boggs; Hassel, Diana M; Magnuson, Roberta J; Hill, Ashley E; McCue, Patrick M; Traub-Dargatz, Josie L

2008-02-01

To determine the adsorptive capability of di-tri-octahedral smectite (DTOS) on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies. 3 C perfringens exotoxins and 9 colostral samples. Alpha, beta, and beta-2 exotoxins were individually co-incubated with serial dilutions of DTOS or bismuth subsalicylate, and the amount of toxin remaining after incubation was determined via toxin-specific ELISAs. Colostral samples from healthy mares were individually co-incubated with serial dilutions of DTOS, and colostral IgG concentrations were determined via single radial immunodiffusion assay. Di-tri-octahedral smectite decreased the amount of each C perfringens exotoxin in co-incubated samples in a dose-dependent manner and was more effective than bismuth subsalicylate at reducing exotoxins in vitro. Decreases in the concentration of IgG were detected in samples of colostrum that were combined with DTOS at 1:4 through 1:16 dilutions, whereas no significant decrease was evident with DTOS at the 1:32 dilution. Di-tri-octahedral smectite effectively adsorbed C perfringens exotoxins in vitro and had a dose-dependent effect on the availability of equine colostral antibodies. Results suggested that DTOS may be an appropriate adjunctive treatment in the management of neonatal clostridiosis in horses. In vivo studies are necessary to fully assess the clinical efficacy of DTOS treatment.

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

Science.gov (United States)

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

2013-01-01

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 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 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.

Development of an integrated model for heat transfer and dynamic growth of Clostridium perfringens during the cooling of cooked boneless ham.

Science.gov (United States)

Amézquita, A; Weller, C L; Wang, L; Thippareddi, H; Burson, D E

2005-05-25

Numerous small meat processors in the United States have difficulties complying with the stabilization performance standards for preventing growth of Clostridium perfringens by 1 log10 cycle during cooling of ready-to-eat (RTE) products. These standards were established by the Food Safety and Inspection Service (FSIS) of the US Department of Agriculture in 1999. In recent years, several attempts have been made to develop predictive models for growth of C. perfringens within the range of cooling temperatures included in the FSIS standards. Those studies mainly focused on microbiological aspects, using hypothesized cooling rates. Conversely, studies dealing with heat transfer models to predict cooling rates in meat products do not address microbial growth. Integration of heat transfer relationships with C. perfringens growth relationships during cooling of meat products has been very limited. Therefore, a computer simulation scheme was developed to analyze heat transfer phenomena and temperature-dependent C. perfringens growth during cooling of cooked boneless cured ham. The temperature history of ham was predicted using a finite element heat diffusion model. Validation of heat transfer predictions used experimental data collected in commercial meat-processing facilities. For C. perfringens growth, a dynamic model was developed using Baranyi's nonautonomous differential equation. The bacterium's growth model was integrated into the computer program using predicted temperature histories as input values. For cooling cooked hams from 66.6 degrees C to 4.4 degrees C using forced air, the maximum deviation between predicted and experimental core temperature data was 2.54 degrees C. Predicted C. perfringens growth curves obtained from dynamic modeling showed good agreement with validated results for three different cooling scenarios. Mean absolute values of relative errors were below 6%, and deviations between predicted and experimental cell counts were within 0.37 log10

Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones

OpenAIRE

Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

2012-01-01

A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved...

Comparison of the Effect of Curing Ingredients Derived from Purified and Natural Sources on Inhibition of Clostridium perfringens Outgrowth during Cooling of Deli-Style Turkey Breast.

Science.gov (United States)

King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

2015-08-01

The antimicrobial impact of purified and natural sources of both nitrite and ascorbate were evaluated against Clostridium perfringens during the postthermal processing cooling period of deli-style turkey breast. The objective of phase I was to assess comparable concentrations of nitrite (0 or 100 ppm) and ascorbate (0 or 547 ppm) from both purified and natural sources. Phase II was conducted to investigate concentrations of nitrite (50, 75, or 100 ppm) from cultured celery juice powder and ascorbate (0, 250, or 500 ppm) from cherry powder to simulate alternative curing formulations. Ground turkey breast (75% moisture, 1.2% salt, pH 6.2) treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in 10 additional hours. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar; experiments were replicated three times. In phase I, uncured, purified nitrite, and natural nitrite treatments without ascorbate had 5.3-, 4.2-, and 4.4-log increases in C. perfringens, respectively, at 15 h, but nitrite and 547 ppm of ascorbate from either source. In phase II, 0, 50, 75, and 100 ppm of nitrite and 50 ppm of nitrite plus 250 ppm of ascorbate supported 4.5-, 3.9-, 3.5-, 2.2-, and 1.5-log increases in C. perfringens, respectively. In contrast, nitrite and 500 ppm of ascorbate or ≥75 ppm of nitrite and ≥250 ppm of ascorbate. These results confirm that equivalent concentrations of nitrite, regardless of the source, provide similar inhibition of C. perfringens during chilling and that ascorbate enhances the antimicrobial effect of nitrite on C. perfringens at concentrations commonly used in alternative cured meats.

Cloning, recombinant production, crystallization and preliminary X-ray diffraction studies of a family 84 glycoside hydrolase from Clostridium perfringens

International Nuclear Information System (INIS)

Ficko-Blean, Elizabeth; Boraston, Alisdair B.

2005-01-01

Crystallization of a family 84 glycoside hydrolase, a putative virulence factor, secreted by C. perfringens is reported. Clostridium perfringens is a ubiquitous environmental organism that is capable of causing a variety of diseases in mammals, including gas gangrene and necrotic enteritis in humans. The activity of a secreted hyaluronidase, attributed to the NagH protein, contributes to the pathogenicity of this organism. The family 84 catalytic module of one of the three homologues of NagH found in C. perfringens (ATCC 13124) has been cloned. The 69 kDa catalytic module of NagJ, here called GH84C, was overproduced in Escherichia coli and purified by immobilized metal-affinity chromatography (IMAC). Crystals belonging to space group I222 or I2 1 2 1 2 1 with unit-cell parameters a = 130.39, b = 150.05, c = 155.43 Å were obtained that diffracted to 2.1 Å. Selenomethionyl crystals have also been produced, leading to the possibility of solving the phase problem by MAD using synchrotron radiation

Mechanisms of antibacterial action of Quinoxaline 1,4-di-N-oxides against Clostridium perfringens and Brachyspira hyodysenteriae

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Fanfan Xu

2016-12-01

Full Text Available Quinoxaline 1,4-di-N-oxides (QdNOs are a class of bioreductive compounds, however their antibacterial mechanisms are still unclarified. The aim of this study was to assess the ability of two representative QdNO drugs, cyadox (CYA and olaquindox (OLA, to produce reactive oxide species (ROS in Gram-positive anaerobe Clostridium perfringens CVCC1125 and Gram-negative anaerobe Brachyspira hyodysenteriae B204. In addition, the effects of QdNOs on the integrity of bacterial cell walls and membranes as well as the morphological alterations and DNA oxidative damage in C. perfringens and B. hyodysenteriae were analyzed. It was demonstrated that under anaerobic conditions, QdNOs were metabolized into the reduced products which did not show any antibacterial activity. A significant dose-related increase of intracellular ROS level and intracellular hydroxyl radicals were evident in bacteria exposed to QdNOs. The result of biochemical assay showed that the cell walls and membranes of the bacteria treated with QdNOs were damaged. After exposure to 1/2MIC to 4MIC of CYA and OLA, C. perfringens and B. hyodysenteriae became elongated and filamentous. Morphological observation with scanning and transmission electron microscopes revealed rupture, loss of cytoplasmic material and cell lysis in QdNO-treated bacteria, indicating serious damage of cells. There was an increase of 8-OHdG in the two strains treated by QdNOs, but it was lower in Gram-positive than in Gram-negative bacteria. Agarose gel electrophoresis showed the degradation of chromosomal DNA in both of the two anaerobes treated by QdNOs. The results suggest that QdNOs may kill C. perfringens and B. hyodysenteriae via the generation of ROS and hydroxyl radicals from the bacterial metabolism of QdNOs, which cause oxidative damage in bacteria under anaerobic conditions.

Ultrasensitive Electrochemical Detection of Clostridium perfringens DNA Based Morphology-Dependent DNA Adsorption Properties of CeO2 Nanorods in Dairy Products

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Xingcan Qian

2018-06-01

Full Text Available Foodborne pathogens such as Clostridium perfringens can cause diverse illnesses and seriously threaten to human health, yet far less attention has been given to detecting these pathogenic bacteria. Herein, two morphologies of nanoceria were synthesized via adjusting the concentration of NaOH, and CeO2 nanorod has been utilized as sensing material to achieve sensitive and selective detection of C. perfringens DNA sequence due to its strong adsorption ability towards DNA compared to nanoparticle. The DNA probe was tightly immobilized on CeO2/chitosan modified electrode surface via metal coordination, and the DNA surface density was 2.51 × 10−10 mol/cm2. Under optimal experimental conditions, the electrochemical impedance biosensor displays favorable selectivity toward target DNA in comparison with base-mismatched and non-complementary DNA. The dynamic linear range of the proposed biosensor for detecting oligonucleotide sequence of Clostridium perfringens was from 1.0 × 10−14 to 1.0 × 10−7 mol/L. The detection limit was 7.06 × 10−15 mol/L. In comparison, differential pulse voltammetry (DPV method quantified the target DNA with a detection limit of 1.95 × 10−15 mol/L. Moreover, the DNA biosensor could detect C. perfringens extracted DNA in dairy products and provided a potential application in food quality control.

Three New Records of Ascomycetes Isolates from Field Soils in Korea

OpenAIRE

Adhikari, Mahesh; Gurung, Sun Kumar; Kim, Hyun Seung; Bazie, Setu; Lee, Hyun Gu; Lee, Hyang Burm; Lee, Youn Su

2017-01-01

Three new records of Ascomycota species (Chaetomium acropullum, Phialemonium globosum, Phialemonium atrogriseum) from field soils in Korea are presented in this study. These newly discovered fungal isolates were isolated from field soils from various places across Gyeongnam, Korea in 2016. All the isolates were identified and described based on morphological characteristics, and rDNA internal transcribed spacer and β-tubulin gene sequence data. Morphological features of these fungal species w...

Distribution of sewage pollution around a maritime Antarctic research station indicated by faecal coliforms, Clostridium perfringens and faecal sterol markers

Energy Technology Data Exchange (ETDEWEB)

Hughes, Kevin A.; Thompson, Anu

2004-02-01

This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste has been released from this site since 1975, creating the potential for long-term contamination of the benthic environment. Faecal coliform concentrations in seawater reached background levels within 300 m of the outfall. In sediment cores, both C. perfringens and faecal coliform concentrations declined with distance from the outfall, though C. perfringens persisted at greater depths in the sediment. High concentrations of 5{beta}(H)-cholestan-3{beta}-ol (coprostanol) relative to the corresponding 5{alpha}-epimer (cholestanol), indicative of sewage pollution, were only found in sediments within 200 m of the sewage outfall. This study has shown that sewage contamination is limited to the immediate vicinity of the sewage outfall. Nevertheless, a sewage treatment plant was installed in February 2003 to reduce this contamination further. - Sewage contamination of seawater and marine sediments near Rothera Research Station (Antarctic Peninsula) was limited to the immediate vicinity of the outfall.

Distribution of sewage pollution around a maritime Antarctic research station indicated by faecal coliforms, Clostridium perfringens and faecal sterol markers

International Nuclear Information System (INIS)

Hughes, Kevin A.; Thompson, Anu

2004-01-01

This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste has been released from this site since 1975, creating the potential for long-term contamination of the benthic environment. Faecal coliform concentrations in seawater reached background levels within 300 m of the outfall. In sediment cores, both C. perfringens and faecal coliform concentrations declined with distance from the outfall, though C. perfringens persisted at greater depths in the sediment. High concentrations of 5β(H)-cholestan-3β-ol (coprostanol) relative to the corresponding 5α-epimer (cholestanol), indicative of sewage pollution, were only found in sediments within 200 m of the sewage outfall. This study has shown that sewage contamination is limited to the immediate vicinity of the sewage outfall. Nevertheless, a sewage treatment plant was installed in February 2003 to reduce this contamination further. - Sewage contamination of seawater and marine sediments near Rothera Research Station (Antarctic Peninsula) was limited to the immediate vicinity of the outfall

A Thermophilic Phage Endolysin Fusion to a Clostridium perfringens-Specific Cell Wall Binding Domain Creates an Anti-Clostridium Antimicrobial with Improved Thermostability

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Steven M. Swift

2015-06-01

Full Text Available Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

The CpAL quorum sensing system regulates production of hemolysins CPA and PFO to build Clostridium perfringens biofilms.

Science.gov (United States)

Vidal, Jorge E; Shak, Joshua R; Canizalez-Roman, Adrian

2015-06-01

Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

Science.gov (United States)

Shak, Joshua R.; Canizalez-Roman, Adrian

2015-01-01

Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. PMID:25824838

Evaluating the performance of a new model for predicting the growth of Clostridium perfringens in cooked, uncured meat and poultry products under isothermal, heating, and dynamically cooling conditions

Science.gov (United States)

Clostridium perfringens Type A is a significant public health threat and may germinate, outgrow, and multiply during cooling of cooked meats. This study evaluates a new C. perfringens growth model in IPMP Dynamic Prediction using the same criteria and cooling data in Mohr and others (2015), but inc...

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

Science.gov (United States)

Rafii, F; Franklin, W; Cerniglia, C E

1990-07-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly.

Antimicrobial susceptibility patterns of Brazilian Haemophilus parasuis field isolates

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Michela Miani

Full Text Available ABSTRACT: Haemophilus parasuis is the etiological agent of Glässer’s disease (GD, an ubiquitous infection of swine characterized by systemic fibrinous polyserositis, polyarthritis and meningitis. Intensive use of antimicrobial agents in swine husbandries during the last years triggered the development of antibiotic resistances in bacterial pathogens. Thus, regular susceptibility testing is crucial to ensure efficacy of different antimicrobial agents to this porcine pathogen. In this study, 50 clinical isolates from South Brazilian pig herds were characterized and analyzed for their susceptibility to commonly used antibiotic. The identification and typing of clinical isolates was carried out by a modified indirect hemagglutination assay combined with a multiplex PCR. The susceptibility of each isolate was analyzed by broth microdilution method against a panel of 21 antimicrobial compounds. We found that field isolates are highly resistance to gentamycin, bacitracin, lincomycin and tiamulin, but sensitive to ampicillin, clindamycin, neomycin, penicillin, danofloxacin and enrofloxacin. Furthermore, an individual susceptibility analysis indicated that enrofloxacin is effective to treat clinical isolates with the exception of those classified as serovar 1. The results presented here firstly demonstrate the susceptibility of Brazilian clinical isolates of H. parasuis to antimicrobials widely used by swine veterinary practitioners and strengthen the need to perform susceptibility test prior to antibiotic therapy during GD outbreaks. In addition, because only six antimicrobial drugs (28.6% were found effective against field isolates, a continuous surveillance of the susceptibility profile should be of major concern to the swine industry.

Isolation of bacteria from diabetic foot ulcers with special reference to anaerobe isolation by simple two-step combustion technique in candle jar

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Jayeeta Haldar

2017-01-01

Results: All the 43 samples were culture positive, of which aerobic Gram-negative bacteria (GNB predominated, followed by Staphylococcus aureus, Enterococcus and diphtheroids. Anaerobes isolated from 21 samples were Peptostreptococcus, Bacteroides, Porphyromonas, Veillonella spp. and Clostridium perfringens by both GasPak and in-house developed and modified candle jar techniques. Imipenem and metronidazole were most sensitive while clindamycin, penicillin and cefoxitin were least sensitive drugs for anaerobes. Aerobic GNB were found to be multidrug resistant, especially to penicillin and cephalosporins. The most sensitive drug was piperacillin-tazobactam. Interpretation & conclusions: For isolation of anaerobes from clinical specimens such as diabetic foot ulcers, modified candle jar technique was found to be as reliable as GasPak system. This modified technique needs to be tested for many other clinical materials which are not yet evaluated.

Isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in laboratory settings.

Science.gov (United States)

Qudratullah; Muhammad, G; Saqib, M; Bilal, M Qamar

2017-08-01

The present study was designed to investigate isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in rabbits and mice. Isolates of P. multocida, S. aureus and Str. agalactiae recovered from field cases of Hemorragic septicemia and mastitis were scrutinized for virulence/pathogenicity and immunogenicity. Mouse LD 50 of P. multocida showed that P. multocida isolate No.1 was more virulent than isolates No. 2 and 3. Virulence of isolate No.1S. aureus and Str. agalactiae revealed that 100, 80% rabbits died within 18h of inoculation. Seven-digit numerical profiles of these 4 isolates with API ® Staph test strips isolates, No.1 (6736153) showed good identification (S. aureus id=90.3%). Indirect ELISA-based serum antibody titers to P. multocida isolate No.1, S. aureus No.1, Str. agalactiae, isolate No.1 elicited high antibody titers 1.9, 1.23, 1.12 respectively. All the pathogens of Isolate No. 1 (P. multocida, S. aureus Str. agalactiae), were high antibody than others isolates. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Science.gov (United States)

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

2013-09-01

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

Inheritance of Carboxin Resistance in a European Field Isolate of Ustilago nuda.

Science.gov (United States)

Newcombe, G; Thomas, P L

2000-02-01

ABSTRACT Two carboxin-resistant field isolates of Ustilago nuda from Europe were crossed with a carboxin-sensitive field isolate from North America. Meiotic tetrads isolated from germinating F(1) teliospores of one of the hybrids were tested for carboxin resistance and mating type. Carboxin resistance was shown to be controlled by a single gene (CBX1R), because a 1:1 segregation of carboxin resistance was observed in all 27 tetrads. Tetrad analysis indicated that the loci for carboxin resistance (Cbx1) and mating type (MAT1) segregate independently but may be located on the same chromosome. Tetrad analysis was not possible with the F(1) hybrid of he other field isolate, and its resistance cannot yet be attributed to CBX1R. Carboxin resistance was qualitatively dominant to sensitivity in vitro, as demonstrated by triad analysis of germinating F(1) teliospores. Quantitative in planta infection percents supported the conclusion that CBX1R is dominant, although incompletely, in the F(1) hybrid of one of the field isolates. Also, fewer than expected carboxin-sensitive F(2) individuals were observed in planta. However, inoculations of host plants with U. nuda have resulted in similar, unexpected variation in the past.

Genome-Wide Transcriptional Profiling of Clostridium perfringens SM101 during Sporulation Extends the Core of Putative Sporulation Genes and Genes Determining Spore Properties and Germination Characteristics.

Science.gov (United States)

Xiao, Yinghua; van Hijum, Sacha A F T; Abee, Tjakko; Wells-Bennik, Marjon H J

2015-01-01

The formation of bacterial spores is a highly regulated process and the ultimate properties of the spores are determined during sporulation and subsequent maturation. A wide variety of genes that are expressed during sporulation determine spore properties such as resistance to heat and other adverse environmental conditions, dormancy and germination responses. In this study we characterized the sporulation phases of C. perfringens enterotoxic strain SM101 based on morphological characteristics, biomass accumulation (OD600), the total viable counts of cells plus spores, the viable count of heat resistant spores alone, the pH of the supernatant, enterotoxin production and dipicolinic acid accumulation. Subsequently, whole-genome expression profiling during key phases of the sporulation process was performed using DNA microarrays, and genes were clustered based on their time-course expression profiles during sporulation. The majority of previously characterized C. perfringens germination genes showed upregulated expression profiles in time during sporulation and belonged to two main clusters of genes. These clusters with up-regulated genes contained a large number of C. perfringens genes which are homologs of Bacillus genes with roles in sporulation and germination; this study therefore suggests that those homologs are functional in C. perfringens. A comprehensive homology search revealed that approximately half of the upregulated genes in the two clusters are conserved within a broad range of sporeforming Firmicutes. Another 30% of upregulated genes in the two clusters were found only in Clostridium species, while the remaining 20% appeared to be specific for C. perfringens. These newly identified genes may add to the repertoire of genes with roles in sporulation and determining spore properties including germination behavior. Their exact roles remain to be elucidated in future studies.

The Role of Clostridium Perfringens in the Syndrome of Intestinal Affection in Children and Possibilities of Drug Correction

Directory of Open Access Journals (Sweden)

G.O. Lezhenko

2014-09-01

Full Text Available The article showed the features of clostridiosis course, caused by Clostridium perfringens, in children of different age groups taking into account the dose of pathogen in feces and pathogenetically grounded possibilities of etiological therapy.

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

DEFF Research Database (Denmark)

Jozefiak, D; Kieronczyk, B; Rawski, M

2014-01-01

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...... 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...... 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...

Serological characterisation of foot-and-mouth disease type 'O' field isolates from Peru: 1992-1994

International Nuclear Information System (INIS)

Espinoza, A.M.

1998-01-01

Nineteen field isolates of foot-and-mouth disease Virus (FMDV) recovered from bovine epithelial samples corresponding to outbreaks present in different regions of Peru, between 1992-1994 were studied. The relationship of the virus isolates to the O/Urubamba vaccine strain of Peru was determined by the calculation of the 'r' values obtained by the liquid-phase blocking ELISA. All the isolates showed 'r' values higher than 0.66 indicating that the vaccine strain should protect against the field strains. Characterization of the field isolates by a trapping ELISA using a panel of monoclonal antibodies against FMDV O/Switzerland and O/Caseros, showed slight differences in the profiles of the field isolates when compared with the O/Urubamba vaccine strain, but no differences were found among all the isolates. (author)

Molecular characterization of acquired enrofloxacin resistance in Mycoplasma synoviae field isolates.

Science.gov (United States)

Lysnyansky, I; Gerchman, I; Mikula, I; Gobbo, F; Catania, S; Levisohn, S

2013-07-01

The in vitro activity of enrofloxacin against 73 Mycoplasma synoviae field strains isolated in Israel and Europe was determined by broth microdilution. Decreased susceptibility to enrofloxacin was identified in 59% of strains, with the MICs ranging from 1 to >16 μg/ml. The estimated MIC50 and MIC90 values for enrofloxacin were 2 and 8 μg/ml, respectively. Moreover, this study showed that 92% of recent Israeli field isolates (2009 to 2011) of M. synoviae have MICs of ≥ 2 μg/ml to enrofloxacin. Comparison of the quinolone resistance-determining regions (QRDRs) in M. synoviae isolates revealed a clear correlation between the presence of one of the amino acid substitutions Asp79-Asn, Thr80-Ala/Ile, Ser81-Pro, and Asp84-Asn/Tyr/His of the ParC QRDR and decreased susceptibility to enrofloxacin (MIC, ≥ 1 μg/ml). Amino acid substitutions at positions GyrA 87, GyrB 401/402, and ParE 420/454 were also identified, but there was no clear-cut correlation with susceptibility to enrofloxacin. Comparison of vlhA molecular profiles revealed the presence of 9 different genotypes in the Israeli M. synoviae field isolates and 10 genotypes in the European isolates; only one vlhA genotype (type 4) was identified in both cohorts. Based on results of vlhA molecular typing, several mechanisms for emergence and dissemination of Israeli enrofloxacin-resistant M. synoviae isolates are suggested.

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

Science.gov (United States)

Rafii, F; Franklin, W; Cerniglia, C E

1990-01-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly. Images PMID:2202258

Metabolic dependent and independent pH-drop shuts down VirSR quorum sensing in Clostridium perfringens.

Science.gov (United States)

Adachi, Keika; Ohtani, Kaori; Kawano, Michio; Singh, Ravindra Pal; Yousuf, Basit; Sonomoto, Kenji; Shimizu, Tohru; Nakayama, Jiro

2018-05-01

Clostridium perfringens produces various exotoxins and enzymes that cause food poisoning and gas gangrene. The genes involved in virulence are regulated by the agr-like quorum sensing (QS) system, which consists of a QS signal synthesis system and a VirSR two-component regulatory system (VirSR TCS) which is a global regulatory system composed of signal sensor kinase (VirS) and response regulator (VirR). We found that the perfringolysin O gene (pfoA) was transiently expressed during mid-log phase of bacterial growth; its expression was rapidly shut down thereafter, suggesting the existence of a self-quorum quenching (sQQ) system. The sQQ system was induced by the addition of stationary phase culture supernatant (SPCS). Activity of the sQQ system was heat stable, and was present following filtration through the ultrafiltration membrane, suggesting that small molecules acted as sQQ agents. In addition, sQQ was also induced by pure acetic and butyric acids at concentrations equivalent to those in the stationary phase culture, suggesting that organic acids produced by C. perfringens were involved in sQQ. In pH-controlled batch culture, sQQ was greatly diminished; expression level of pfoA extended to late-log growth phase, and was eventually increased by one order of magnitude. Furthermore, hydrochloric acid induced sQQ at the same pH as was used in organic acids. SPCS also suppressed the expression of genes regulated by VirSR TCS. Overall, the expression of virulence factors of C. perfringens was downregulated by the sQQ system, which was mediated by primary acidic metabolites and acidic environments. This suggested the possibility of pH-controlled anti-virulence strategies. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Protein profiles of field isolates ofBacillus anthracis from different endemic areas of Indonesia

Directory of Open Access Journals (Sweden)

M Bhakti Poerwadikarta

1998-03-01

Full Text Available Sonicated cell-free extract proteins of 14 field isolates ofBacillus anthracis from six different endemic areas of Indonesia were analyzed by the use of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE methods . The protein profiles of each field isolate tested demonstrated slightly different at the protein bands with molecular weights of 18, 37, 52, 65 and 70 kDa, and varied between the field isolates and vaccine strains. The variation could provide clues to the source of anthrax transmission whether it was originated from similar strain or not.

Clostridium perfringens removal in different stages in a Drinking Water Treatments plant; Eliminacion de Clostidium perfringens en diversas etapas de una estacion de tratamiento de aguas potables

Energy Technology Data Exchange (ETDEWEB)

Ormad, M. P.; Lanao, M.; Goni, P.; Ibarz, C.; Ovelleiro, J. L.

2008-07-01

The purpose of this research is to evaluate the effectiveness of different stages, which take part in the conventional treatments used in the drinking water treatment plants in Spain, in the removal of a microbiological indicator of faecal pollution, Clostridium perfringens. The stages studied are pre oxidation with chlorine and ozone, chemical precipitation, adsorption with activated coal and filtration sand. The pre oxidation, either with sodium hypochlorite or with ozone, gets final recounts below the detection limit with the conditions studied (> 8 log). In the rest of stages, the removal is minimal, achieving 1,32 logarithmic units at best case. (Author) 6 refs.

Clostridium perfringens infection complicating periprosthetic fracture fixation about the hip: successful treatment with early aggressive debridement.

LENUS (Irish Health Repository)

Baker, Joseph F

2012-07-13

Periprosthetic fracture and infection are both challenges following hip arthroplasty. We report the case of an 87 year old female who underwent open reduction and internal fixation of a periprosthetic femoral fracture. Her post-operative course was complicated by infection with Clostridium perfringens. Early aggressive antibiotic treatment and surgical debridement were successful, and allowed retention of the original components.

Human alpha-defensin-1 protects cells from intoxication with Clostridium perfringens iota toxin.

Science.gov (United States)

Fischer, Stephan; Popoff, Michel R; Barth, Holger

2018-03-01

Iota toxin is produced by Clostridium perfringens type E strains and associated with diarrhea in cattle and lambs. This binary protein toxin comprises the enzyme component iota a (Ia), which ADP-ribosylates G-actin, and the separate transport component iota b (Ib), which delivers Ia into the cytosol of target cells. Ib binds to cell receptors and forms biologically active toxin complexes with Ia, which cause rounding of adherent cells due to the destruction of the actin cytoskeleton. Here, we report that the human peptide α-defensin-1 protects cultured cells including human colon cells from intoxication with iota toxin. In contrast, the related ß-defensin-1 had no effect, indicating a specific mode of action. The α-defensin-1 did not inhibit ADP-ribosylation of actin by Ia in vitro. Pretreatment of Ib with α-defensin-1 prior to addition of Ia prevented intoxication. Additionally, α-defensin-1 protected cells from cytotoxic effects mediated by Ib in the absence of Ia, implicating that α-defensin-1 interacts with Ib to prevent the formation of biologically active iota toxin on cells. In conclusion, the findings contribute to a better understanding of the functions of α-defensin-1 and suggest that this human peptide might be an attractive starting point to develop novel pharmacological options to treat/prevent diseases associated with iota toxin-producing Clostridium perfringens strains.

Molecular analysis of the interaction between Clostridium perfringens Enterotoxin and Claudins

OpenAIRE

Protze, Jonas

2015-01-01

Claudins are essential constituents of Tight Junctions (TJs) and responsible for maintenance of these cell-cell contacts. Binding of Clostridium perfringens Enterotoxin’s C-terminal domain (cCPE) to the extracellular loop 2 (EZS2) of claudins, especially Cld3, Cld4 and Cld6-Cld9 causes a reversible opening of TJs. Thus, a structure-function analysis of this system is relevant for biomedical application, since cCPE could be used to enhance paracellular drug uptake. Furthermore cCPE respectivel...

CPm gene diversity in field isolates of Citrus tristeza virus from Colombia.

Science.gov (United States)

Oliveros-Garay, Oscar Arturo; Martinez-Salazar, Natalhie; Torres-Ruiz, Yanneth; Acosta, Orlando

2009-01-01

The nucleotide sequence diversity of the CPm gene from 28 field isolates of Citrus tristeza virus (CTV) was assessed by SSCP and sequence analyses. These isolates showed two major shared haplotypes, which differed in distribution: A1 was the major haplotype in 23 isolates from different geographic regions, whereas R1 was found in isolates from a discrete region. Phylogenetic reconstruction clustered A1 within an independent group, while R1 was grouped with mild isolates T30 from Florida and T385 from Spain. Some isolates contained several minor haplotypes, which were very similar to, and associated with, the major haplotype.

Permanent-magnet Faraday isolator with the field intensity of 25 kOe

Energy Technology Data Exchange (ETDEWEB)

Mironov, E A; Snetkov, I L; Voitovich, A V; Palashov, O V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2013-08-31

A Faraday isolator with a single magneto-optical element is constructed and experimentally tested. It provides the isolation ratio of 30 dB at an average laser radiation power of 650 W. These parameters are obtained by increasing the field intensity in the magnetic system of the isolator and employing a low-absorption magneto-optical element. (elements of laser devices)

ELIMINATION OF CLOSTRIDIUM PERFRINGENS DURING SURPLUS ACTIVATED SLUDGE HANDLING

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Klaudiusz Grűbel

2014-10-01

Basis on the results of the research was concluded that microwave radiation (700W and 900W shows disintegration action expressed in COD value in the supernatant increase: 12 times increase value of COD with power 700W and 13 times for 900W radiation power. Electromagnetic wave contributed to partial higienisation of surplus activated sludge. The number of Clostridium perfringens decrease about 52% and 56% during the 120s of higienisation process with power 700W and 900W, respectively. Reduction of the overall number of bacteria under the influence of microwave radiation was 42% and 51% (respectively for 700W and 900W, and sticks from the family Enterobacteriaceae from 54% to 70% depending on the power of radiation, the time of operation and biochemical properties.

Dynamics of plc gene transcription and α-toxin production during growth of Clostridium perfringens strains with contrasting α-toxin production

DEFF Research Database (Denmark)

Abildgaard, Lone; Schramm, Andreas; Rudi, Knut

2009-01-01

The aim of the present study was to investigate transcription dynamics of the α-toxin-encoding plc gene relative to two housekeeping genes (gyrA and rplL) in batch cultures of three Clostridium perfringens strains with low, intermediate, and high levels of α-toxin production, respectively. The plc...... transcript level was always low in the low α-toxin producing strain. For the two other strains, plc transcription showed an inducible pattern and reached a maximum level in the late exponential growth phase. The transcription levels were however inversely correlated to α-toxin production for the two strains....... We propose that this discrepancy is due to differences in plc translation rates between the strains and that strain-specific translational rates therefore must be determined before α-toxin production can be extrapolated from transcript levels in C. perfringens....

Characterization of field isolates of Magnaporthe oryzae with mating type, DNA fingerprinting, and pathogenicity assays

Science.gov (United States)

Due to the harmful nature of the rice blast fungus, Magnaporthe oryzae, it is beneficial to characterize field isolates to help aid in the deployment of resistance (R) genes in rice. In the present study, 190 field isolates of M. oryzae, collected from rice fields of Yunnan province in China, were a...

Padronização da titulação da toxina épsilon de Clostridium perfringens tipo D em linhagem contínua de células como alternativa ao bioensaio animal Standardization of the titration of the epsilon toxin of Clostridium perfringens type D in cell line as an alternative to animal bioassay

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Milton Formiga Souza Júnior

2010-03-01

Full Text Available Enterotoxemia, também chamada de doença do rim pulposo, doença que acomete os ruminantes domésticos, é causada pela ação da toxina épsilon produzida pelo Clostridium perfringens tipo D, um anaeróbio comumente isolado do solo e das fezes de animais sadios. O método tradicional de diagnóstico baseia-se na detecção e classificação dessa exotoxina no conteúdo intestinal por meio da soroneutralização em camundongos. Com isso, o objetivo deste estudo foi padronizar um teste para detecção e titulação dessa toxina in vitro e compará-lo ao fenômeno in vivo. Para isso, uma partida de toxina épsilon de Clostridium perfringens tipo D foi titulada em camundongos e em várias linhagens contínuas de células. Após a determinação da linhagem celular mais sensível, realizaram-se ensaios de titulação in vitro de diluições de uma partida de toxina, comparando-os com os títulos in vivo conhecidos. Os resultados foram agrupados, e foi desenvolvida a equação matemática que melhor adaptou-se aos intervalos trabalhados. A linhagem MDCK, além de mais sensível, demonstrou que o fenômeno observado in vitro pode ser expresso por meio da equação matemática que apresenta uma correlação de 98,33%, com a dose mínima mortal determinada in vivo. Portanto, a linhagem MDCK permite titular a toxina épsilon de C. perfringens tipo D de forma específica e sensível, além de ser uma técnica prática, rápida e que dispensa o uso de animais.Enterotoxemia (also called pulpy kidney disease is an enteric disease, that affect ruminants, produced by epsilon toxin from Clostridium perfringens type D, an anaerobic commonly isolated from soil and feces of healthy animals. The diagnostic is based on detection of this exotoxin in the intestinal content by soroneutralization in mice. Therefore, this study aimed to standardize a test for detection and titration of the toxin in vitro, and compare it with the phenomenon in vivo. A volume of epsilon

Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin.

Science.gov (United States)

Takehara, Masaya; Takagishi, Teruhisa; Seike, Soshi; Oda, Masataka; Sakaguchi, Yoshihiko; Hisatsune, Junzo; Ochi, Sadayuki; Kobayashi, Keiko; Nagahama, Masahiro

2017-08-11

Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

Veal calves produce less antibodies against C. perfringens alpha toxin compared to beef calves

OpenAIRE

Valgaeren, Bonnie; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

2015-01-01

Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, wher...

Comparative analysis of the genomes of two field isolates of the rice blast fungus Magnaporthe oryzae.

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Minfeng Xue

Full Text Available Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice worldwide. The fungal pathogen is notorious for its ability to overcome host resistance. To better understand its genetic variation in nature, we sequenced the genomes of two field isolates, Y34 and P131. In comparison with the previously sequenced laboratory strain 70-15, both field isolates had a similar genome size but slightly more genes. Sequences from the field isolates were used to improve genome assembly and gene prediction of 70-15. Although the overall genome structure is similar, a number of gene families that are likely involved in plant-fungal interactions are expanded in the field isolates. Genome-wide analysis on asynonymous to synonymous nucleotide substitution rates revealed that many infection-related genes underwent diversifying selection. The field isolates also have hundreds of isolate-specific genes and a number of isolate-specific gene duplication events. Functional characterization of randomly selected isolate-specific genes revealed that they play diverse roles, some of which affect virulence. Furthermore, each genome contains thousands of loci of transposon-like elements, but less than 30% of them are conserved among different isolates, suggesting active transposition events in M. oryzae. A total of approximately 200 genes were disrupted in these three strains by transposable elements. Interestingly, transposon-like elements tend to be associated with isolate-specific or duplicated sequences. Overall, our results indicate that gain or loss of unique genes, DNA duplication, gene family expansion, and frequent translocation of transposon-like elements are important factors in genome variation of the rice blast fungus.

Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin

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Masaya Takehara

2017-08-01

Full Text Available Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

Multiplex PCR assay for the simultaneous detection of C. perfringens, P. aeruginosa and K. pneumoniae

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Pradeepkiran Jangampalli Adi

2015-11-01

Results and conclusions: Through this approach, the above pathogens were detected simultaneously with high specificity in pure cultures and from the blood and urine samples. The results were correlated with normal diagnostic process, and proved to be more sensitive and specific diagnostic technique in the simultaneous detection of C. perfringens, P. aeruginosa and K. pneumoniae.

[A case of freeze-dried gas gangrene antitoxin for the treatment of Clostridium perfringens sepsis].

Science.gov (United States)

Yoshida, Juichiro; Nakamura, Hideki; Yamada, Shinya; Sekoguchi, Satoru; Suzuki, Takahiro; Tomatsuri, Naoya; Sato, Hideki; Okuyama, Yusuke; Kimura, Hiroyuki; Yoshida, Norimasa

2015-02-01

A 66-year-old man was admitted to our hospital with high fever. We diagnosed a gas-containing liver abscess and performed percutaneous abscess drainage. However, 15 hours after admission, he developed massive intravascular hemolysis and acidosis. Sepsis due to Clostridium perfringens was suspected and we treated the patient intensively with multidisciplinary approaches, including antibiotics, mechanical ventilation, and renal replacement therapy. Furthermore, we administered freeze-dried gas gangrene antitoxin. Despite intensive care, the patient died 43 hours after admission.

Analyses of the radiation-caused characteristics change in SOI MOSFETs using field shield isolation

International Nuclear Information System (INIS)

Hirano, Yuuichi; Maeda, Shigeru; Fernandez, Warren; Iwamatsu, Toshiaki; Yamaguchi, Yasuo; Maegawa, Shigeto; Nishimura, Tadashi

1999-01-01

Reliability against radiation ia an important issue in silicon on insulator metal oxide semiconductor field effect transistors (SOI MOSFETs) used in satellites and nuclear power plants and so forth which are severely exposed to radiation. Radiation-caused characteristic change related to the isolation-edge in an irradiated environment was analyzed on SOI MOSFETs. Moreover short channel effects for an irradiated environment were investigated by simulations. It was revealed that the leakage current which was observed in local oxidation of silicon (LOCOS) isolated SOI MOSFETs was successfully suppressed by using field shield isolation. Simulated potential indicated that the potential rise at the LOCOS edge can not be seen in the case of field shield isolation edge which does not have physical isolation. Also it was found that the threshold voltage shift caused by radiation in short channel regime is severer than that in long regime channel. In transistors with a channel length of 0.18μm, a potential rise of the body region by radiation-induced trapped holes can be seen in comparison with that of 1.0μm. As a result, we must consider these effects for designing deep submicron devices used in an irradiated environment. (author)

Field isolation for GaN MOSFETs on AlGaN/GaN heterostructure with boron ion implantation

International Nuclear Information System (INIS)

Jiang, Y; Wang, Q P; Wang, D J; Tamai, K; Li, L A; Ao, J-P; Ohno, Y; Shinkai, S; Miyashita, T; Motoyama, S-I

2014-01-01

We report the investigation of boron ion implantation as a device field isolation process for GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure. In the mesa isolation region of a bar-type MOSFET, a parasitic MOS-channel existed and widened the designed channel width, which would result in an overestimated mobility compared with a ring-type MOSFET. After boron ions implantation in the isolation region, the overestimation of field-effect mobility of bar-type MOSFETs was eliminated. The sub-threshold characteristics and on-state drain current of the bar-type MOSFETs coincide with the ring-type devices. Long-channel ring-type MOSFETs, with and without ion implantation, were fabricated on the recess region to evaluate the sub-threshold characteristics. The MOSFETs with boron ions implanted into the recess region showed a low drain current up to the gate bias of 10V. The result indicated that boron ion implantation prevented the formation of parasitic MOS-channel in the isolation region and achieved field isolation. The current–voltage characteristics of MOSFETs with the normal recess condition demonstrated no degradation of device performance after boron ions implanted into the isolation region. Boron ion implantation by further optimization can be a field isolation method for GaN MOSFETs. (paper)

Stimulation of Clostridium perfringens enterotoxin formation by caffeine and theobromine.

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Labbe, R G; Nolan, L L

1981-01-01

In the presence of 100 micrograms of caffeine per ml or 200 micrograms of theobromine per ml, sporulation of Clostridium perfringens NCTC 8679 rose from less than 1 to 80 or 85%. Enterotoxin concentration increased from undetectable levels to 450 micrograms/mg of cell extract protein. Heat-resistant spore levels increased from less than 1,000 to between 1 X 10(7) and 2 X 10(7)/ml. These effects were partially reversible by the addition of adenosine or thymidine. In the case of NCTC 8238, caffeine and theobromine caused a three- to fourfold increase in the percentages of cells possessing refractile spores and a similar increase in enterotoxin concentration. Heat-resistant spore levels, however, were unaffected. Inosine was ineffective in promoting sporulation in NCTC 8679. PMID:6271685

Comparison of toxicity neutralization-, ELISA- and PCR tests for typing of Clostridium perfringens and detection of the enterotoxin gene by PCR

DEFF Research Database (Denmark)

Møller, Kristian; Ahrens, Peter

1996-01-01

A polymerase chain reaction (PCR) was developed for the specific amplification of a part of each of the five Clostridium perfringens toxin genes: alpha (alpha), beta (beta), epsilon (epsilon), iota (iota), and enterotoxin (CPE). While the toxicity neutralization test (TNT) only showed limited...

Comparison of Pseudomonas aeruginosa isolates from mink by serotyping and pulsed-field gel electrophoresis

DEFF Research Database (Denmark)

Hammer, Anne Sofie; Pedersen, Karl; Andersen, Thomas Holmen

2003-01-01

Isolates of Pseudomonas aeruginosa from clinical infections in mink were subjected to serotyping and pulsed-field gel electrophoresis (PFGE) using SpeI. A total of 212 isolates of P aeruginosa from the year 1998 to 2001 were included in this study: 168 isolates from mink obtained from 74 farm out...

Characterization of isolates of meloidogyne from rice-wheat production fields in Nepal.

Science.gov (United States)

Pokharel, Ramesh R; Abawi, George S; Zhang, Ning; Duxbury, John M; Smart, Christine D

2007-09-01

Thirty-three isolates of root-knot nematode were recovered from soil samples from rice-wheat fields in Nepal and maintained on rice cv. BR 11. The isolates were characterized using morphology, host range and DNA sequence analyses in order to ascertain their identity. Results indicated phenotypic similarity (juvenile measurements, perennial pattern, host range and gall shape) of the Nepalese isolates with Meloidogyne graminicola, with minor variations. The rice varieties LA 110 and Labelle were susceptible to all of the Nepalese isolates, but differences in the aggressiveness of the isolates were observed. Phylogenetic analyses based on the sequences of partial internal transcribed spacer (ITS) of the rRNA genes indicated that all Nepalese isolates formed a distinct clade with known isolates of M. graminicola with high bootstrap support. Furthermore, two groups were identified within the M. graminicola clade. No correlation between ITS haplotype and aggressiveness or host range was found among the tested isolates.

Isolation of imidacloprid degrading bacteria from cotton fields

International Nuclear Information System (INIS)

Shahid, M.N.; Jabeen, F.; Hassan, S.W.

2008-01-01

Imidacloprid is cyclodiene organochlorine, used as an insecticide all over the world an possess a serious environmental threat. It is mostly used for cotton insects (bollworm, aphid and white fly). For isolation of imidacloprid degrading bacteria three soil samples were collected from cotton fields of district Layyah having five years history of use. Soil samples were analyzed by measuring pH and electric conductivity. The isolation of imidacroprid degrading bacteria was performed by enrichment technique. Fourteen bacterial strains: S/sub i-a/, S/sub i-b/, S/sub i-c/, S/sub i-d/, S/sub i-e/, S/sub a-a/, S/a-b/, S/a-c/, S/a-d/, S/sub b-a/, S/sub b-b/, S/sub b-c/, S/sub b-d/ and S/b-e/ were isolated on the basis of their colony morphologies. The purified colonies were characterized morphologically physiologically and biochemically. Gram staining was done and Gram staining was done and Gram negative strains were confirmed on macConkey agar and Eosin methylene blue. Bacterial strains were also checked for different minimal media in which only carbon source was the imidacloprid. For this purpose FTW, FTW without N/sun 2/, NSM, M/sub 9/ and MM/sub 2/ media were used and their optical densities were taken on spectrophotometer, isolates were checked for resistance to antibiotics and heavy metals. On the basis of these characteristics. S/sub a-c/ and S/sub l-d/ were assigned to Enterobacteriaceae, S/sub a-b/ to Pseudomonadaceae and rest of the bacterial isolates were affiliated. (author)

Assessment of Clostridium perfringens spore response to high hydrostatic pressure and heat with nisin.

Science.gov (United States)

Gao, Yulong; Qiu, Weifen; Wu, Ding; Fu, Qiang

2011-08-01

The elimination of spores from low-acid foods presents food-processing and food-safety challenges to high-pressure processing (HPP) developers as bacterial spores are extremely resistant to pressure. Therefore, the effects of pressure (400-800 MPa), temperature (35-95 °C), and nisin (0-496 IU/mL) on the inactivation of Clostridium perfringens AS 64701 spores at various pressure-holding times (7.5-17.5 min) were explored. A second-order polynomal equation for HPP- and nisin-induced inactivation of C. perfringens spores was constructed with response surface methodology. Experiment results showed that the experimental values were shown to be significantly in agreement with the predicted values because the adjusted determination coefficient (R (Adj)²) was 0.9708 and the level of significance was P pressure of 654 Mpa, temperature of 74 °C, pressure-holding time of 13.6 min, and nisin concentration of 328 IU/mL. The validation of the model equation for predicting the optimum response values was verified effectively by ten test points that were not used in the establishment of the model. Compared with conventional HPP techniques, the main process advantages of HPP-nisin combination sterilization in the UHT milk are, lower pressure, temperature, natural preservative (nisin), and in a shorter treatment time. The synergistic inactivation of bacteria by HPP-nisin combination is a promising and natural method to increase the efficiency and safety of high-pressure pasteurization.

Effect of low-dose gamma irradiation on enterotoxin-positive strains of Clostridium perfringens Type A

International Nuclear Information System (INIS)

Barnhart, H.M. Jr.

1976-01-01

The effect of low-dose gamma irradiation on selected enterotoxin producing strains of Clostridium perfringens Type A was studied. The radioresistance of three strains NCTC-8239, NCTC-10239 and NCTC-8798 in 0.1 percent peptone water, beef gravy and ground beef was determined for both vegetative cells and spores. D 10 values were approximately 30 Krad in 0.1 percent peptone water and 175 Krad in beef menstruums. D 10 values for spores were approximately 250 Krad in 0.1 percent peptone water and 335 Krad in beef. Low-level irradiation induced a 2 hr lag for cell recovery at 37 0 C following irradiation though this was strain dependent. Heat resistance of vegetative cells decreased following irradiation, although one strain was stimulated in growth response and unaltered in its heat resistance. Spore activation and germination were not affected by low-level irradiation. Spores were not significantly inactivated at this level. Irradiation had no effect on subsequent survival of vegetative cells stored at cold temperatures. Enterotoxin production by irradiated cultures was not affected by the irradiation treatment. A method for quantitating C. perfringens enterotoxin using crossed-immunoelectrophoresis was developed. It was found that this technique could detect at least .05 g of enterotoxin, could utilize crude enterotoxin preparations and was more sensitive than other methods based on biological activity

Enteric Diseases of Poultry with Special Attention to Clostridium perfringens

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Hafez Mohamed Hafez

2011-06-01

Full Text Available The enteric heath of growing poultry is imperative to success of the production. The basic role of poultry production is turning feed stuffs into meat. Any changes in this turning process, due to mechanical, chemical or biological disturbance of digestive system (enteric disorders is mostly accompanied with high economic losses due to poor performance, increased mortality rates and increased medication costs. The severity of clinical signs and course of the disorders are influenced several factors such as management, nutrition and the involved agent(s. Several pathogens (viruses, bacteria and parasites are incriminated as possible cause of enteric disorders either alone (mono-causal, in synergy with other micro-organisms (multi-causal, or with non-infectious causes such as feed and /or management related factors. In addition, excessive levels of mycotoxins and biogenic amines in feed lead to enteric disorders. Also factors such as high stocking density, poor litter conditions, poor hygiene and high ammonia level and other stressful situation may reduce the resistance of the birds and increases their susceptibility to infections. Under field conditions, however, under filed conditions it is difficult to determine whether the true cause of enteric disorders, is of infectious or non-infectious origin. In recent years and since the ban of use of antimicrobial growth promoters in several countries the incidence of intestinal disorders especially those caused by clostridial infection was drastically increased. The present review described in general the several factors involved in enteric disorders and summarized the available literatures about Clostridium perfringens infection in poultry.

Efficacy in the field of two anticoccidial vaccines for broilers

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Guido Grilli

2010-01-01

Full Text Available We compared two attenuated anticoccidial vaccines, administered to broilers by spray into the incubator (88,000 males and 210,100 females. Vaccine A container five species of Eimeria and vaccine B three. Zootechnical performance was similar in the two groups, with mean lesion scores no higher than 1; vaccine A caused only duodenal lesions, while vaccine B also caused typhlitis. Maximum oocyst count was 23,000/g feces at age 28 days with vaccine A and 38,000 at 21 days with vaccine B. Broilers vaccinated with vaccine B had more frequent enteric symptoms, and C. perfringens isolation.

Comparative transcriptional and genomic analysis of Plasmodium falciparum field isolates.

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Margaret J Mackinnon

2009-10-01

Full Text Available Mechanisms for differential regulation of gene expression may underlie much of the phenotypic variation and adaptability of malaria parasites. Here we describe transcriptional variation among culture-adapted field isolates of Plasmodium falciparum, the species responsible for most malarial disease. It was found that genes coding for parasite protein export into the red cell cytosol and onto its surface, and genes coding for sexual stage proteins involved in parasite transmission are up-regulated in field isolates compared with long-term laboratory isolates. Much of this variability was associated with the loss of small or large chromosomal segments, or other forms of gene copy number variation that are prevalent in the P. falciparum genome (copy number variants, CNVs. Expression levels of genes inside these segments were correlated to that of genes outside and adjacent to the segment boundaries, and this association declined with distance from the CNV boundary. This observation could not be explained by copy number variation in these adjacent genes. This suggests a local-acting regulatory role for CNVs in transcription of neighboring genes and helps explain the chromosomal clustering that we observed here. Transcriptional co-regulation of physical clusters of adaptive genes may provide a way for the parasite to readily adapt to its highly heterogeneous and strongly selective environment.

Effects of Eimeria maxima and Clostridium perfringens infections on Cecal Microbiome in Broiler Chickens Analyzed by 16S rRNA Sequencing

Science.gov (United States)

Background: Necrotic enteritis (NE) and coccidiosis are considered two of the priority enteric diseases impacting poultry production in the U.S. and Europe, and are responsible for the annual economic loss of US $6 billion and $ 3 billion, respectively. NE is caused by Clostridium perfringens (CP), ...

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

DEFF Research Database (Denmark)

Abildgaard, Lone; Højberg, Ole; Schramm, Andreas

2010-01-01

Proliferation of Clostridium perfringens type A in the broiler intestinal tract is related to poor growth and litter quality, and can under certain conditions lead to the development of necrotic enteritis (NE), a severe gastrointestinal disease in broilers. The aim of the present study was to inv...... quantification of C. perfringens type A in broilers, a real-time PCR assay, targeting the α-toxin-encoding plc gene, was developed for use in ileal and caecal samples and was shown to be a fast and reliable alternative to conventional plate counting....

Generation of an isolated sub-30 attosecond pulse in a two-color laser field and a static electric field

International Nuclear Information System (INIS)

Zhang Gang-Tai; Zhang Mei-Guang; Bai Ting-Ting

2012-01-01

We theoretically investigate high-order harmonic generation (HHG) from a helium ion model in a two-color laser field, which is synthesized by a fundamental pulse and its second harmonic pulse. It is shown that a supercontinuum spectrum can be generated in the two-color field. However, the spectral intensity is very low, limiting the application of the generated attosecond (as) pulse. By adding a static electric field to the synthesized two-color field, not only is the ionization yield of electrons contributing to the harmonic emission remarkably increased, but also the quantum paths of the HHG can be significantly modulated. As a result, the extension and enhancement of the supercontinuum spectrum are achieved, producing an intense isolated 26-as pulse with a bandwidth of about 170.5 eV. In particular, we also analyse the influence of the laser parameters on the ultrabroad supercontinuum spectrum and isolated sub-30-as pulse generation. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Change in antimicrobial susceptibility of Mycoplasma gallisepticum field isolates.

Science.gov (United States)

Gharaibeh, Saad; Al-Rashdan, Mohammad

2011-06-02

This study compares the antimicrobial susceptibility over time between two groups of Mycoplasma gallisepticum (MG) isolates from the same geographical area. Minimum inhibitory concentration of 13 antimicrobials was determined against two groups of MG isolates from chickens. Group 1 strains (n=22) were isolated in 2004-2005 while group 2 strains (n=7) were isolated in 2007-2008. Minimum inhibitory concentration 50 for group 1 versus group 2 was 4/4, 0.5/0.5, ≤ 0.031/≥ 64, ≤ 0.031/2, ≤ 0.031/0.125, 1/0.5, 1/1, ≤ 0.031/≤ 0.031, ≤ 0.031/2, ≤ 0.031/2, 1/4, ≤ 0.031/0.062, and 0.062/2 μg/ml against gentamicin, spectinomycin, erythromycin, tilmicosin, tylosin, florfenicol, thiamphenicol, tiamulin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline, respectively. There was a statistically significant increase in resistance of group 2 to erythromycin, tilmicosin, tylosin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline. This dramatic increase in resistance against 8 antimicrobials belonging to three different families of antimicrobials in a relatively short period of time appears to be rare and of concern. The cause of this increased resistance observed in group 2 of MG isolates was not determined and should be further investigated. Monitoring of MG field strain susceptibility is highly recommended to implement successful treatment and prophylaxis programs in endemic areas. Copyright © 2011 Elsevier B.V. All rights reserved.

Identification of Brucella ovis exclusive genes in field isolates from Argentina.

Science.gov (United States)

Alvarez, Lucía Paula; García-Effrón, Guillermo; Robles, Carlos Alejandro

2016-03-01

Brucellosis caused by Brucella ovis is one of the most important infectious diseases of sheep. The aim of this study was to determine the presence of genes both inside and outside the specific B. ovis pathogenicity island 1 (BOPI-1) in a large collection of field isolates of B. ovis and other Brucella spp. from Argentina. The BOV_A0500 gene from B. ovis BOPI-1 was identified in all 104 B. ovis isolates studied. The BOPI-1 complete sequence was found to be conserved in 10 B. ovis strains from the collection, for which whole genome sequencing was performed. The BOV_0198 gene, which is outside BOPI-1 and considered exclusive to B. ovis, showed 90-100% identity with genomic regions of B. ovis, B. melitensis, B. abortus, B. canis, B. suis, B. microti, B. ceti and B. pinnipedialis. The results demonstrate that BOPI-1 is the only exclusive genetic region of B. ovis and marine Brucella spp. and that it is highly conserved in B. ovis field isolates from Argentina. Copyright © 2016 Elsevier Ltd. All rights reserved.

Caracterización molecular y resistencia antimicrobiana de aislamientos de Clostridium perfringens de diferentes orígenes en Costa Rica

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María del Mar Gamboa-Coronado

2011-12-01

Full Text Available Clostridium perfringens es un bacilo Gram positivo, esporulado, anaerobio, ampliamente distribuido en la naturaleza, que produce cuatro toxinas principales α, β, ε y ι, las cuales permiten su clasificación en cinco toxinotipos (A-E. Algunas cepas producen una enterotoxina (CPE, codificada por el gen cpe, que causa diarrea en seres humanos y en algunos animales. La presencia de los genes de estas toxinas y la sensibilidad a los antibióticos se determinó en 81 cepas de C. perfringens previamente aisladas y que habían sido mantenidas a -80°C; 20 de suelos, 20 de origen animal, 20 de origen humano y 21 de alimentos cocidos no relacionados con brotes alimentarios. De acuerdo con los resultados de PCR, todas las cepas fueron clasificadas como C. perfringens tipo A, debido a que solo se les detectó el gen de la toxina α, mientras que el gen de la enterotoxina (cpe se detectó en dos cepas (2.5% aisladas de alimentos, tal como ha sido descrito en otras regiones del mundo. El 44% de las cepas fue resistente a algún antibiótico; clindamicina (41%, cloranfenicol (25%, penicilina (22% y metronidazol (20%. En general, las cepas provenientes de suelos presentaron los mayores porcentajes de resistencia a casi todos los antibióticos. El 40% de las cepas de suelo presentó multiresistencia (a tres o más grupos de antibióticos, el 30% de las de origen humano, el 14% de las de alimentos y el 5% de las de origen animal. Las altas tasas de resistencia encontradas podrían deberse al amplio uso de antibióticos como promotores de crecimiento de plantas y animales y esas cepas resistentes podrían actuar como reservorio de genes de resistencia que pueden transferirse entre bacterias de diversos ambientes.

Comparative analysis of field-isolate and monkey-adapted Plasmodium vivax genomes.

Science.gov (United States)

Chan, Ernest R; Barnwell, John W; Zimmerman, Peter A; Serre, David

2015-03-01

Significant insights into the biology of Plasmodium vivax have been gained from the ability to successfully adapt human infections to non-human primates. P. vivax strains grown in monkeys serve as a renewable source of parasites for in vitro and ex vivo experimental studies and functional assays, or for studying in vivo the relapse characteristics, mosquito species compatibilities, drug susceptibility profiles or immune responses towards potential vaccine candidates. Despite the importance of these studies, little is known as to how adaptation to a different host species may influence the genome of P. vivax. In addition, it is unclear whether these monkey-adapted strains consist of a single clonal population of parasites or if they retain the multiclonal complexity commonly observed in field isolates. Here we compare the genome sequences of seven P. vivax strains adapted to New World monkeys with those of six human clinical isolates collected directly in the field. We show that the adaptation of P. vivax parasites to monkey hosts, and their subsequent propagation, did not result in significant modifications of their genome sequence and that these monkey-adapted strains recapitulate the genomic diversity of field isolates. Our analyses also reveal that these strains are not always genetically homogeneous and should be analyzed cautiously. Overall, our study provides a framework to better leverage this important research material and fully utilize this resource for improving our understanding of P. vivax biology.

Electricity Generation in Microbial Fuel Cell (MFC) by Bacterium Isolated from Rice Paddy Field Soil

Science.gov (United States)

Fakhirruddin, Fakhriah; Amid, Azura; Salim, Wan Wardatul Amani Wan; Suhaida Azmi, Azlin

2018-03-01

Microbial fuel cell (MFC) is an alternative approach in generating renewable energy by utilising bacteria that will oxidize organic or inorganic substrates, producing electrons yielded as electrical energy. Different species of exoelectrogenic bacteria capable of generating significant amount of electricity in MFC has been identified, using various organic compounds for fuel. Soil sample taken from rice paddy field is proven to contain exoelectrogenic bacteria, thus electricity generation using mixed culture originally found in the soil, and pure culture isolated from the soil is studied. This research will isolate the exoelectrogenic bacterial species in the rice paddy field soil responsible for energy generation. Growth of bacteria isolated from the MFC is observed by measuring the optical density (OD), cell density weight (CDW) and viable cell count. Mixed bacterial species found in paddy field soil generates maximum power of 77.62 μW and 0.70 mA of current. In addition, the research also shows that the pure bacterium in rice paddy field soil can produce maximum power and current at 51.32 μW and 0.28 mA respectively.

Impact of Clean-Label Antimicrobials and Nitrite Derived from Natural Sources on the Outgrowth of Clostridium perfringens during Cooling of Deli-Style Turkey Breast.

Science.gov (United States)

King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

2015-05-01

Organic acids and sodium nitrite have long been shown to provide antimicrobial activity during chilling of cured meat products. However, neither purified organic acids nor NaNO2 is permitted in products labeled natural and both are generally avoided in clean-label formulations; efficacy of their replacement is not well understood. Natural and clean-label antimicrobial alternatives were evaluated in both uncured and in alternative cured (a process that uses natural sources of nitrite) deli-style turkey breast to determine inhibition of Clostridium perfringens outgrowth during 15 h of chilling. Ten treatments of ground turkey breast (76% moisture, 1.2% salt) included a control and four antimicrobials: 1.0% tropical fruit extract, 0.7% dried vinegar, 1.0% cultured sugar-vinegar blend, and 2.0% lemon-vinegar blend. Each treatment was formulated without (uncured) and with nitrite (PCN; 50 ppm of NaNO2 from cultured celery juice powder). Treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in an additional 10 h. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar. Uncured control and PCN-only treatments allowed for 4.6- and 4.2-log increases at 15 h, respectively, and although all antimicrobial treatments allowed less outgrowth than uncured and PCN, the degree of inhibition varied. The 1.0% fruit extract and 1.0% cultured sugar-vinegar blend were effective at controlling populations at or below initial levels, whether or not PCN was included. Without PCN, 0.7% dried vinegar and 2.0% lemon-vinegar blend allowed for 2.0- and 2.5-log increases, respectively, and ∼1.5-log increases with PCN. Results suggest using clean-label antimicrobials can provide for safe cooling following the study parameters, and greater

Fatal Clostridium perfringens sepsis due to emphysematous gastritis and literature review.

Science.gov (United States)

Sarvari, Karoly Peter; Vasas, Bela; Kiss, Ildiko; Lazar, Andrea; Horvath, Istvan; Simon, Marianna; Peto, Zoltan; Urban, Edit

2016-08-01

A 76-year-old female patient was admitted to the Level I Emergency Department of University of Szeged with severe abdominal pain and vomiting. The clinical assessment with laboratory tests and radiological investigations confirmed severe sepsis associated with intravascular hemolysis and multiorgan failure and acute pancreatitis. On the abdominal CT, besides of other abnormalities, the presence of gas bubbles in the stomach, small intestines and liver were seen. The gastric alterations pointed to emphysematous gastritis. Despite of the medical treatment, the patient's condition quickly deteriorated and eight hours after admission the patient died. The autopsy evaluation revealed systemic infection of abdominal origin caused by gas-producing Gram-positive bacteria, and the post-mortem microbiological cultures confirmed the presence of Cloctridium perfringens in many abdominal organs. Emphysematous gastritis seemed to be the primary infectious focus. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vaccination with Clostridium perfringens recombinant proteins in combination with Montanide™ ISA 71 VG adjuvant increases protection against experimental necrotic enteritis in commercial broiler chickens

Science.gov (United States)

This study was performed to compare four Clostridium perfringens recombinant proteins as vaccine candidates using the Montanide™ ISA 71 VG adjuvant in an experimental model of necrotic enteritis. Broiler chickens were immunized with clostridial recombinant proteins with ISA 71 VG, and intestinal le...

Acid Sphingomyelinase Promotes Cellular Internalization of Clostridium perfringens Iota-Toxin.

Science.gov (United States)

Nagahama, Masahiro; Takehara, Masaya; Miyamoto, Kazuaki; Ishidoh, Kazumi; Kobayashi, Keiko

2018-05-20

Clostridium perfringens iota-toxin is a binary actin-ADP-ribosylating toxin composed of the enzymatic component Ia and receptor binding component Ib. Ib binds to a cell surface receptor, forms Ib oligomer in lipid rafts, and associates with Ia. The Ia-Ib complex then internalizes by endocytosis. Here, we showed that acid sphingomyelinase (ASMase) facilitates the cellular uptake of iota-toxin. Inhibitions of ASMase and lysosomal exocytosis by respective blockers depressed cell rounding induced by iota-toxin. The cytotoxicity of the toxin increased in the presence of Ca 2+ in extracellular fluids. Ib entered target cells in the presence but not the absence of Ca 2+ . Ib induced the extracellular release of ASMase in the presence of Ca 2+ . ASMase siRNA prevented the cell rounding induced by iota-toxin. Furthermore, treatment of the cells with Ib resulted in the production of ceramide in cytoplasmic vesicles. These observations showed that ASMase promotes the internalization of iota-toxin into target cells.

Frequency of resistance in obligate anaerobic bacteria isolated from dogs, cats, and horses to antimicrobial agents.

Science.gov (United States)

Lawhon, S D; Taylor, A; Fajt, V R

2013-11-01

Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ≥ 16/8 μg/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ≥ 2 μg/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ≥ 32 μg/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ≥ 8 μg/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ≥ 32 μg/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ≥ 2 μg/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro.

Selection of Infective Arbuscular Mycorrhizal Fungal Isolates for Field Inoculation

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Elisa Pellegrino

2010-09-01

Full Text Available Arbuscular mycorrhizal (AM fungi play a key role in host plant growth and health, nutrient and water uptake, plant community diversity and dynamics. AM fungi differ in their symbiotic performance, which is the result of the interaction of two fungal characters, infectivity and efficiency. Infectivity is the ability of a fungal isolate to establish rapidly an extensive mycorrhizal symbiosis and is correlated with pre-symbiotic steps of fungal life cycle, such as spore germination and hyphal growth. Here, different AM fungal isolates were tested, with the aim of selecting infective endophytes for field inoculation. Greenhouse and microcosm experiments were performed in order to assess the ability of 12 AM fungal isolates to produce spores, colonize host roots and to perform initial steps of symbiosis establishment, such as spore germination and hyphal growth. AM fungal spore production and root colonization were significantly different among AM fungal isolates. Spore and sporocarp densities ranged from 0.8 to 7.4 and from 0.6 to 2.0 per gram of soil, respectively, whereas root colonization ranged from 2.9 to 72.2%. Percentage of spore or sporocarp germination ranged from 5.8 to 53.3% and hyphal length from 4.7 to 79.8 mm. The ordination analysis (Redundancy Analysis, RDA showed that environmental factors explained about 60% of the whole variance and their effect on fungal infectivity variables was significant (P = 0.002. The biplot clearly showed that variables which might be used to detect infective AM fungal isolates were hyphal length and root colonization. Such analysis may allow the detection of the best parameters to select efficient AM fungal isolates to be used in agriculture.

Technological properties of bacteriocin-producing lactic acid bacteria isolated from Pico cheese an artisanal cow's milk cheese.

Science.gov (United States)

Ribeiro, S C; Coelho, M C; Todorov, S D; Franco, B D G M; Dapkevicius, M L E; Silva, C C G

2014-03-01

Evaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making. Eight isolates obtained from Pico cheese produced in Azores (Portugal) were found to produce bacteriocins against Listeria monocytogenes and three isolates against Clostridium perfringens. They were identified as Lactococcus lactis and Enterococcus faecalis and submitted to technological tests: growth at different conditions of temperature and salt, acid production, proteolysis, lipolysis, coexistence, enzymatic profile and autolytic capacity. Safety evaluation was performed by evaluating haemolytic, gelatinase and DNase activity, resistance to antibiotics and the presence of virulence genes. Some isolates presented good technological features such as high autolytic activity, acid and diacetyl production. Lactococcus lactis was negative for all virulence genes tested and inhibit the growth of all Lactic acid bacteria (LAB) isolates. Enterococci were positive for the presence of some virulence genes, but none of the isolates were classified as resistant to important antibiotics. The bacteriocin-producing Lc. lactis present good potential for application in food as adjunct culture in cheese production. The study also reveals good technological features for some Enterococcus isolates. Bacteriocin-producing strains presented important technological properties to be exploited as new adjunct culture for the dairy industry, influencing flavour development and improve safety. © 2013 The Society for Applied Microbiology.

Plasmodium falciparum field isolates from South America use an atypical red blood cell invasion pathway associated with invasion ligand polymorphisms

DEFF Research Database (Denmark)

Lopez-Perez, Mary; Villasis, Elizabeth; Machado, Ricardo L D

2012-01-01

Studies of Plasmodium falciparum invasion pathways in field isolates have been limited. Red blood cell (RBC) invasion is a complex process involving two invasion protein families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins, which are polymorphic and not fully...... characterized in field isolates. To determine the various P. falciparum invasion pathways used by parasite isolates from South America, we studied the invasion phenotypes in three regions: Colombia, Peru and Brazil. Additionally, polymorphisms in three members of the EBL (EBA-181, EBA-175 and EBL-1) and five...... pathways and the ligand polymorphisms differed substantially among the Colombian and Brazilian isolates while the Peruvian isolates represent an amalgam of those present in the Colombian and Brazilian field isolates. The NrTrCr invasion profile was associated with the presence of the PfRh2a pepC variant...

The application of rumen simulation technique (RUSITEC) for studying dynamics of the bacterial community and metabolome in rumen fluid and the effects of a challenge with Clostridium perfringens.

Science.gov (United States)

Wetzels, Stefanie U; Eger, Melanie; Burmester, Marion; Kreienbrock, Lothar; Abdulmawjood, Amir; Pinior, Beate; Wagner, Martin; Breves, Gerhard; Mann, Evelyne

2018-01-01

The rumen simulation technique (RUSITEC) is a well-established semicontinuous in vitro model for investigating ruminal fermentation; however, information on the stability of the ruminal bacterial microbiota and metabolome in the RUSITEC system is rarely available. The availability of high resolution methods, such as high-throughput sequencing and metabolomics improve our knowledge about the rumen microbial ecosystem and its fermentation processes. Thus, we used Illumina MiSeq 16S rRNA amplicon sequencing and a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS to evaluate the dynamics of the bacterial community and the concentration of several metabolites in a RUSITEC experiment as a function of time and in response to a challenge with a pathogenic Clostridium perfringens (C. perfringens) strain. After four days of equilibration, samples were collected on days 5, 6, 7, 10, 12 and 15 of the steady-state and experimental period. From a total of six fermenters, three non-infected fermenters were used for investigating time-dependent alterations; three fermenters were incubated with C. perfringens and compared with the non-infected vessels at days 10, 12 and 15. Along the time-line, there was no statistically significant change of the overall bacterial community, however, some phylotypes were enriched at certain time points. A decrease in Fibrobacter and Elusimicrobia over time was followed by an increase in Firmicutes and Actinobacteria. In contrast, classical fermentation measurements such as pH, redox potential, NH3-N, short chain fatty acids and the concentrations of metabolites determined by metabolomics (biogenic amines, hexoses and amino acids) remained stable throughout the experiment. In response to C. perfringens addition the concentrations of several amino acids increased. Although the overall bacterial community was not altered here either, some minor changes such as an enrichment of Synergistetes and Bacteroidetes were

The application of rumen simulation technique (RUSITEC for studying dynamics of the bacterial community and metabolome in rumen fluid and the effects of a challenge with Clostridium perfringens.

Directory of Open Access Journals (Sweden)

Stefanie U Wetzels

Full Text Available The rumen simulation technique (RUSITEC is a well-established semicontinuous in vitro model for investigating ruminal fermentation; however, information on the stability of the ruminal bacterial microbiota and metabolome in the RUSITEC system is rarely available. The availability of high resolution methods, such as high-throughput sequencing and metabolomics improve our knowledge about the rumen microbial ecosystem and its fermentation processes. Thus, we used Illumina MiSeq 16S rRNA amplicon sequencing and a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS to evaluate the dynamics of the bacterial community and the concentration of several metabolites in a RUSITEC experiment as a function of time and in response to a challenge with a pathogenic Clostridium perfringens (C. perfringens strain. After four days of equilibration, samples were collected on days 5, 6, 7, 10, 12 and 15 of the steady-state and experimental period. From a total of six fermenters, three non-infected fermenters were used for investigating time-dependent alterations; three fermenters were incubated with C. perfringens and compared with the non-infected vessels at days 10, 12 and 15. Along the time-line, there was no statistically significant change of the overall bacterial community, however, some phylotypes were enriched at certain time points. A decrease in Fibrobacter and Elusimicrobia over time was followed by an increase in Firmicutes and Actinobacteria. In contrast, classical fermentation measurements such as pH, redox potential, NH3-N, short chain fatty acids and the concentrations of metabolites determined by metabolomics (biogenic amines, hexoses and amino acids remained stable throughout the experiment. In response to C. perfringens addition the concentrations of several amino acids increased. Although the overall bacterial community was not altered here either, some minor changes such as an enrichment of Synergistetes and

Clostridium Perfringens Epsilon Toxin Binds to Membrane Lipids and Its Cytotoxic Action Depends on Sulfatide.

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Carles Gil

Full Text Available Epsilon toxin (Etx is one of the major lethal toxins produced by Clostridium perfringens types B and D, being the causal agent of fatal enterotoxemia in animals, mainly sheep and goats. Etx is synthesized as a non-active prototoxin form (proEtx that becomes active upon proteolytic activation. Etx exhibits a cytotoxic effect through the formation of a pore in the plasma membrane of selected cell targets where Etx specifically binds due to the presence of specific receptors. However, the identity and nature of host receptors of Etx remain a matter of controversy. In the present study, the interactions between Etx and membrane lipids from the synaptosome-enriched fraction from rat brain (P2 fraction and MDCK cell plasma membrane preparations were analyzed. Our findings show that both Etx and proEtx bind to lipids extracted from lipid rafts from the two different models as assessed by protein-lipid overlay assay. Lipid rafts are membrane microdomains enriched in cholesterol and sphingolipids. Binding of proEtx to sulfatide, phosphatidylserine, phosphatidylinositol (3-phosphate and phosphatidylinositol (5-phosphate was detected. Removal of the sulphate groups via sulfatase treatment led to a dramatic decrease in Etx-induced cytotoxicity, but not in proEtx-GFP binding to MDCK cells or a significant shift in oligomer formation, pointing to a role of sulfatide in pore formation in rafts but not in toxin binding to the target cell membrane. These results show for the first time the interaction between Etx and membrane lipids from host tissue and point to a major role for sulfatides in C. perfringens epsilon toxin pathophysiology.

Identification of new IS711 insertion sites in Brucella abortus field isolates.

Science.gov (United States)

Mancilla, Marcos; Ulloa, Marcos; López-Goñi, Ignacio; Moriyón, Ignacio; María Zárraga, Ana

2011-08-03

Brucellosis is a zoonosis caused by Brucella spp., a group of highly homogeneous bacteria. The insertion sequence IS711 is characteristic of these bacteria, and occurs in variable numbers and positions, but always constant within a given species. This species-associated polymorphism is used in molecular typing and identification. Field isolates of B. abortus, the most common species infecting cattle, typically carry seven IS711 copies (one truncated). Thus far, IS711 transposition has only been shown in vitro and only for B. ovis and B. pinnipedialis, two species carrying a high number of IS711 copies, but never in other Brucella species, neither in vitro nor in field strains. We found several B. abortus strains isolated from milk and aborted fetuses that carried additional IS711 copies in two hitherto undescribed insertion sites: one in an intergenic region near to the 3' end of a putative lactate permease gene and the other interrupting the sequence of a marR transcriptional regulator gene. Interestingly, the second type of insertion was identified in isolates obtained repeatedly from the same herd after successive brucellosis outbreaks, an observation that proves the stability and virulence of the new genotype under natural conditions. Sequence analyses revealed that the new copies probably resulted from the transposition of a single IS711 copy common to all Brucella species sequenced so far. Our results show that the replicative transposition of IS711 can occur under field conditions. Therefore, it represents an active mechanism for the emergence of genetic diversity in B. abortus thus contributing to intra-species genetic polymorphism.

Molecular characterisation of Aspergillus flavus isolates from peanut fields in India using AFLP

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Diwakar Singh

2015-09-01

Full Text Available Aflatoxin contamination of peanut, due to infection by Aspergillus flavus, is a major problem of rain-fed agriculture in India. In the present study, molecular characterisation of 187 Aspergillus flavus isolates, which were sampled from the peanut fields of Gujarat state in India, was performed using AFLP markers. On a pooled cluster analysis, the markers could successfully discriminate among the ‘A’, ‘B’ and ‘G’ group A. flavus isolates. PCoA analysis also showed equivalent results to the cluster analysis. Most of the isolates from one district could be clustered together, which indicated genetic similarity among the isolates. Further, a lot of genetic variability was observed within a district and within a group. The results of AMOVA test revealed that the variance within a population (84% was more than that between two populations (16%. The isolates, when tested by indirect competitive ELISA, showed about 68.5% of them to be atoxigenic. Composite analysis between the aflatoxin production and AFLP data was found to be ineffective in separating the isolate types by aflatoxigenicity. Certain unique fragments, with respect to individual isolates, were also identified that may be used for development of SCAR marker to aid in rapid and precise identification of isolates.

Influence of day-length and isolates of Phytophthora infestans on field resistance to late blight of potato.

Science.gov (United States)

Mihovilovich, E; Munive, S; Bonierbale, M

2010-04-01

Main and interaction effects of day-length and pathogen isolate on the reaction and expression of field resistance to Phytophthora infestans were analyzed in a sample of standard clones for partial resistance to potato late blight, and in the BCT mapping population derived from a backcross of Solanum berthaultii to Solanum tuberosum. Detached leaves from plants grown in field plots exposed to short- and long day-length conditions were independently inoculated with two P. infestans isolates and incubated in chambers under short- and long photoperiods, respectively. Lesion growth rate (LGR) was used for resistance assessment. Analysis of variance revealed a significant contribution of genotype x isolate x day-length interaction to variation in LGR indicating that field resistance of genotypes to foliar late blight under a given day-length depended on the infecting isolate. An allele segregating from S. berthaultii with opposite effects on foliar resistance to late blight under long- and short day-lengths, respectively, was identified at a quantitative trait locus (QTL) that mapped on chromosome 1. This allele was associated with positive (decreased resistance) and negative (increased resistance) additive effects on LGR, under short- and long day-length conditions, respectively. Disease progress on whole plants inoculated with the same isolate under field conditions validated the direction of its effect in short day-length regimes. The present study suggests the occurrence of an isolate-specific QTL that displays interaction with isolate behavior under contrasting environments, such as those with different day-lengths. This study highlights the importance of exposing genotypes to a highly variable population of the pathogen under contrasting environments when stability to late blight resistance is to be assessed or marker-assisted selection is attempted for the manipulation of quantitative resistance to late blight.

Isolating strong-field dynamics in molecular systems

Science.gov (United States)

Orenstein, Gal; Pedatzur, Oren; Uzan, Ayelet J.; Bruner, Barry D.; Mairesse, Yann; Dudovich, Nirit

2017-05-01

Strong-field ionization followed by recollision provides a unique pump-probe measurement which reveals a range of electronic processes, combining sub-Angstrom spatial and attosecond temporal resolution. A major limitation of this approach is imposed by the coupling between the spatial and temporal degrees of freedom. In this paper we focus on the study of high harmonic generation and demonstrate the ability to isolate the internal dynamics—decoupling the temporal information from the spatial one. By applying an in situ approach we reveal the universality of the intrinsic pump-probe measurement and establish its validity in molecular systems. When several orbitals are involved we identify the fingerprint of the transition from the single-channel case into the multiple-channel dynamics, where complex multielectron phenomena are expected to be observed.

Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients.

Science.gov (United States)

Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

2015-07-01

Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics.

Plasmodium falciparum field isolates from South America use an atypical red blood cell invasion pathway associated with invasion ligand polymorphisms.

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Mary Lopez-Perez

Full Text Available Studies of Plasmodium falciparum invasion pathways in field isolates have been limited. Red blood cell (RBC invasion is a complex process involving two invasion protein families; Erythrocyte Binding-Like (EBL and the Reticulocyte Binding-Like (PfRh proteins, which are polymorphic and not fully characterized in field isolates. To determine the various P. falciparum invasion pathways used by parasite isolates from South America, we studied the invasion phenotypes in three regions: Colombia, Peru and Brazil. Additionally, polymorphisms in three members of the EBL (EBA-181, EBA-175 and EBL-1 and five members of the PfRh (PfRh1, PfRh2a, PfRh2b, PfRh4, PfRh5 families were determined. We found that most P. falciparum field isolates from Colombia and Peru invade RBCs through an atypical invasion pathway phenotypically characterized as resistant to all enzyme treatments (NrTrCr. Moreover, the invasion pathways and the ligand polymorphisms differed substantially among the Colombian and Brazilian isolates while the Peruvian isolates represent an amalgam of those present in the Colombian and Brazilian field isolates. The NrTrCr invasion profile was associated with the presence of the PfRh2a pepC variant, the PfRh5 variant 1 and EBA-181 RVNKN variant. The ebl and Pfrh expression levels in a field isolate displaying the NrTrCr profile also pointed to PfRh2a, PfRh5 and EBA-181 as being possibly the major players in this invasion pathway. Notably, our studies demonstrate the uniqueness of the Peruvian P. falciparum field isolates in terms of their invasion profiles and ligand polymorphisms, and present a unique opportunity for studying the ability of P. falciparum parasites to expand their invasion repertoire after being reintroduced to human populations. The present study is directly relevant to asexual blood stage vaccine design focused on invasion pathway proteins, suggesting that regional invasion variants and global geographical variation are likely to

Changes in Sensitivity Levels of Botrytis spp. Population Isolated from Lily to Fungicides and Control under Field Condition

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Soosang Hahm

2013-03-01

Full Text Available Forty eight isolates of Botrytis elliptica and 23 isolates of B. cinerea from several locations in Korea were tested for resistance to fungicides used in the farmer's fields. Isolation frequency of B. elliptica having EC50 (effective concentration of 50% value 500−1000 μg/ml to benomyl and mancozeb appeared highly, suggesting that the two fungicides are not effective in controlling leaf blight of lily in the field. The isolates were tested for resistance to fungicides procymidone and iprodione which were most commonly used in the farmer's fields. The rates of EC50 value 5−50 μg/ml to procymidome and iprodione were 93.7% and 100%, respectively, and those of 0−0.1 μg/ml to diethofencarb+carbendazim and fludioxonil were 98.0% and 93.8%, respectively. In the rain-protected cultivation, control of leaf blight of lily was the most effective when iprodine, diethofencarb+ carbendazim, and fludioxonil were sprayed alternately four times during the growing season.

Identification of new IS711 insertion sites in Brucella abortus field isolates

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Moriyón Ignacio

2011-08-01

Full Text Available Abstract Background Brucellosis is a zoonosis caused by Brucella spp., a group of highly homogeneous bacteria. The insertion sequence IS711 is characteristic of these bacteria, and occurs in variable numbers and positions, but always constant within a given species. This species-associated polymorphism is used in molecular typing and identification. Field isolates of B. abortus, the most common species infecting cattle, typically carry seven IS711 copies (one truncated. Thus far, IS711 transposition has only been shown in vitro and only for B. ovis and B. pinnipedialis, two species carrying a high number of IS711 copies, but never in other Brucella species, neither in vitro nor in field strains. Results We found several B. abortus strains isolated from milk and aborted fetuses that carried additional IS711 copies in two hitherto undescribed insertion sites: one in an intergenic region near to the 3' end of a putative lactate permease gene and the other interrupting the sequence of a marR transcriptional regulator gene. Interestingly, the second type of insertion was identified in isolates obtained repeatedly from the same herd after successive brucellosis outbreaks, an observation that proves the stability and virulence of the new genotype under natural conditions. Sequence analyses revealed that the new copies probably resulted from the transposition of a single IS711 copy common to all Brucella species sequenced so far. Conclusions Our results show that the replicative transposition of IS711 can occur under field conditions. Therefore, it represents an active mechanism for the emergence of genetic diversity in B. abortus thus contributing to intra-species genetic polymorphism.

Field studies on two rock phosphate solubilizing actinomycete isolates as biofertilizer sources

Science.gov (United States)

Mba, Caroline C.

1994-03-01

Recently biotechnology is focusing attention on utilization of biological resources to solve a number of environmental problems such as soil fertility management. Results of microbial studies on earthworm compost in the University of Nigeria farm identified a number of rock phosphate solubilizing actinomycetes. Two of these, isclates 02 and 13, were found to be efficient rock phosphate (RP) solubilizers and fast-growing cellulolytic microbes producing extracellular hydrolase enzymes. In this preliminary field study the two microbial isolates were investigated with respect to their effects on the growth of soybean and egusi as well as their effect on the incidence of toxicity of poultry droppings. Application of these isolates in poultry manure-treated field plots, as microbial fertilizers, brought about yield increases of 43% and 17% with soybeans and 19% and 33% with egusi, respectively. Soil properties were also improved. With isolates 02 and 13, the soil available phosphorus increased at the five-leaf stage, while N-fixation in the soil increased by 45% or 11% relative to control. It was further observed that air-dried poultry manure after four days of incubation was still toxic to soybean. The toxic effect of the applied poultry manure was reduced or eliminated with microbial fertilizers 02 or 13, respectively. The beneficial effects of the microbial organic fertilizer are discussed. Justification for more intensive research on rock phosphate organic fertilizer is highlighted.

Microbial enhanced heavy crude oil recovery through biodegradation using bacterial isolates from an Omani oil field.

Science.gov (United States)

Al-Sayegh, Abdullah; Al-Wahaibi, Yahya; Al-Bahry, Saif; Elshafie, Abdulkadir; Al-Bemani, Ali; Joshi, Sanket

2015-09-16

Biodegradation is a cheap and environmentally friendly process that could breakdown and utilizes heavy crude oil (HCO) resources. Numerous bacteria are able to grow using hydrocarbons as a carbon source; however, bacteria that are able to grow using HCO hydrocarbons are limited. In this study, HCO degrading bacteria were isolated from an Omani heavy crude oil field. They were then identified and assessed for their biodegradation and biotransformation abilities under aerobic and anaerobic conditions. Bacteria were grown in five different minimum salts media. The isolates were identified by MALDI biotyper and 16S rRNA sequencing. The nucleotide sequences were submitted to GenBank (NCBI) database. The bacteria were identified as Bacillus subtilis and B. licheniformis. To assess microbial growth and biodegradation of HCO by well-assay on agar plates, samples were collected at different intervals. The HCO biodegradation and biotransformation were determined using GC-FID, which showed direct correlation of microbial growth with an increased biotransformation of light hydrocarbons (C12 and C14). Among the isolates, B. licheniformis AS5 was the most efficient isolate in biodegradation and biotransformation of the HCO. Therefore, isolate AS5 was used for heavy crude oil recovery experiments, in core flooding experiments using Berea core plugs, where an additional 16 % of oil initially in place was recovered. This is the first report from Oman for bacteria isolated from an oil field that were able to degrade and transform HCO to lighter components, illustrating the potential use in HCO recovery. The data suggested that biodegradation and biotransformation processes may lead to additional oil recovery from heavy oil fields, if bacteria are grown in suitable medium under optimum growth conditions.

Field study on the epidemiology and pathogenicity of different isolates of bovine Ostertagia spp.

Science.gov (United States)

Al Saqur, I; Armour, J; Bairden, K; Dunn, A M; Jennings, F W; Murray, M

1982-11-01

The epidemiological features of three different isolates of bovine Ostertagia spp under similar initial levels of larval challenge were compared in the field. Two of the isolates, consisting mainly of Ostertagia ostertagi, and a low proportion of Skrjabinagia lyrata conformed in epidemiological behaviour with those investigated by previous workers, though the worm burdens which established did not give rise to the expected clinical signs. The third isolate behaved in a different way, yielding very high faecal egg counts which were followed by high pasture larval counts, heavy worm burdens and severe clinical disease. This isolate, while consisting mainly of O ostertagi and a few S lyrata, also contained a proportion of O leptospicularis, and it is suggested that this species may influence the dynamics of the host-parasite relationship in bovine ostertagiasis.

Measurement of weak magnetic field of corrosion current of isolated corrosion center

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I. V. Bardin

2015-01-01

Full Text Available A very small magnetic field of corrosion current, of the order of 10−4 Oe, generated by isolated zinc inclusion in a copper platelet placed in electrolyte has been measured for the first time with a highly sensitive giant magneto-impedance magnetometer. The total corrosion current of the inclusion is estimated comparing the measured magnetic field distribution with corresponding theoretical calculation. The estimated value of the total corrosion current turns out to be in reasonable agreement with that one obtained in the standard gravimetric measurement.

Molecular analysis of Salmonella enteritidis isolates from the Caribbean by pulsed-field gel electrophoresis

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Abiodun Adesiyun

2000-11-01

Full Text Available Using pulsed-field gel electrophoresis (PFGE, between 1987 and 1996 we analyzed Salmonella enteritidis isolates from gastroenteritis cases in four Caribbean countries: Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by XbaI revealed 13 distinctive PFGE patterns. The most prevalent XbaI PFGE patterns were group 1 (88 of 129 isolates, 68.2% and group 2 (26 of 129, 20.2%. The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4% belonged to XbaI PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9% belonged to group 1. SpeI digestion of S. enteritidis genome was not as discriminatory as XbaI. Overall, of the 129 isolates, 67 of them (51.9% exhibited resistance to one or more of the 12 antimicrobial agents that we tested. The prevalence of resistance was 53.8% for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0% for those from Barbados, 28.6% for those from Saint Lucia, and 100.0% for one isolate from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129 isolates, 45.7%, followed by furadantoin (10 of 129, 7.8%, ampicillin (7 of 129, 5.4%, and carbamycin (5 of 129, 3.9%.

Molecular analysis of Salmonella enteritidis isolates from the Caribbean by pulsed-field gel electrophoresis.

Science.gov (United States)

Adesiyun, A; Carson, A; McAdoo, K; Bailey, C

2000-11-01

Using pulsed-field gel electrophoresis (PFGE), between 1987 and 1996 we analyzed Salmonella enteritidis isolates from gastroenteritis cases in four Caribbean countries: Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by XbaI revealed 13 distinctive PFGE patterns. The most prevalent XbaI PFGE patterns were group 1 (88 of 129 isolates, 68.2%) and group 2 (26 of 129, 20.2%). The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4%) belonged to XbaI PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9%) belonged to group 1. SpeI digestion of S. enteritidis genome was not as discriminatory as XbaI. Overall, of the 129 isolates, 67 of them (51.9%) exhibited resistance to one or more of the 12 antimicrobial agents that we tested. The prevalence of resistance was 53.8% for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0% for those from Barbados, 28.6% for those from Saint Lucia, and 100.0% for one isolate from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129 isolates, 45.7%), followed by furadantoin (10 of 129, 7.8%), ampicillin (7 of 129, 5.4%), and carbamycin (5 of 129, 3.9%).

Molecular analysis of Salmonella enteritidis isolates from the Caribbean by pulsed-field gel electrophoresis

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Adesiyun Abiodun

2000-01-01

Full Text Available Using pulsed-field gel electrophoresis (PFGE, between 1987 and 1996 we analyzed Salmonella enteritidis isolates from gastroenteritis cases in four Caribbean countries: Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by XbaI revealed 13 distinctive PFGE patterns. The most prevalent XbaI PFGE patterns were group 1 (88 of 129 isolates, 68.2% and group 2 (26 of 129, 20.2%. The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4% belonged to XbaI PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9% belonged to group 1. SpeI digestion of S. enteritidis genome was not as discriminatory as XbaI. Overall, of the 129 isolates, 67 of them (51.9% exhibited resistance to one or more of the 12 antimicrobial agents that we tested. The prevalence of resistance was 53.8% for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0% for those from Barbados, 28.6% for those from Saint Lucia, and 100.0% for one isolate from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129 isolates, 45.7%, followed by furadantoin (10 of 129, 7.8%, ampicillin (7 of 129, 5.4%, and carbamycin (5 of 129, 3.9%.

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

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Necrotic enteritis is an enteric disease of poultry resulting from infection by Clostridium perfringens with co-infection 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 ente...

Cellular Uptake of the Clostridium perfringens Binary Iota-Toxin

Science.gov (United States)

Blöcker, Dagmar; Behlke, Joachim; Aktories, Klaus; Barth, Holger

2001-01-01

The binary iota-toxin is produced by Clostridium perfringens type E strains and consists of two separate proteins, the binding component iota b (98 kDa) and an actin-ADP-ribosylating enzyme component iota a (47 kDa). Iota b binds to the cell surface receptor and mediates the translocation of iota a into the cytosol. Here we studied the cellular uptake of iota-toxin into Vero cells. Bafilomycin A1, but not brefeldin A or nocodazole, inhibited the cytotoxic effects of iota-toxin, indicating that toxin is translocated from an endosomal compartment into the cytoplasm. Acidification (pH ≤ 5.0) of the extracellular medium enabled iota a to directly enter the cytosol in the presence of iota b. Activation by chymotrypsin induced oligomerization of iota b in solution. An average mass of 530 ± 28 kDa for oligomers was determined by analytical ultracentrifugation, indicating heptamer formation. The entry of iota-toxin into polarized CaCo-2 cells was studied by measuring the decrease in transepithelial resistance after toxin treatment. Iota-toxin led to a significant decrease in resistance when it was applied to the basolateral surface of the cells but not following application to the apical surface, indicating a polarized localization of the iota-toxin receptor. PMID:11292715

Antimicrobial activity of Lactobacillus strains of chicken origin against bacterial pathogenss.

Science.gov (United States)

Dec, Marta; Puchalski, Andrzej; Nowaczek, Anna; Wernicki, Andrzej

2016-03-01

This study was conducted to identify and evaluate the antimicrobial activity of some Lactobacillus isolates of chicken origin. Among 90 isolates 14 Lactobacillus species were distinguished using MALDI-TOF mass spectrometry and 16S-ARDRA. The dominant species was L. salivarius (34.4%), followed by L. johnsonii (23.3%), L. crispatus (13.3%) and L. reuteri (11.1%). All lactobacilli were screened for antimicrobial activity against wild-type strains of Salmonella enterica, Escherichia coli, and Clostridium perfringens. Results from the agar slab method showed that all Lactobacillus isolates were able to produce active compounds on solid media with antagonistic properties against these pathogens. The highest sensitivity to lactobacilli was observed in C. perfringens strains, and the lowest in E. coli. Lactobacillus salivarius exhibited particularly strong antagonism towards all of the indicator bacteria. Strains of L. ingluviei and L. johnsonii and one strain of L. salivarius (10d) selectively inhibited the growth of C. perfringens. No antimicrobial activity of many Lactobacillus isolates was observed when cell-free culture supernatant was used in a well diffusion assay. All Lactobacillus isolates exhibited the ability to produce H2O2 and proved to be hydrophobic (excluding one of L. salivarius). [Int Microbiol 19(1):57-67 (2016)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Characterization of field isolates of Suid herpesvirus 1 (Aujeszky's disease virus) as derivatives of attenuated vaccine strains

DEFF Research Database (Denmark)

Christensen, Laurids Siig; Medveczky, I.; Strandbygaard, Bertel

1992-01-01

Field isolates of suid herpesvirus 1 (Aujeszky's disease virus) from Poland and Hungary were identified by restriction fragment pattern analysis as derivatives of attenuated vaccine strains. The Polish isolates were found to be related to the BUK-TK-900 strain (Suivac A) which is widely used...

The limitations of pulsed-field gel electrophoresis for analysis of Yersinia enterocolitica isolates.

Science.gov (United States)

Gilpin, B J; Robson, B; Lin, S; Hudson, J A; Weaver, L; Dufour, M; Strydom, H

2014-09-01

This study describes the analysis of 432 isolates of Yersinia enterocolitica by pulsed-field gel electrophoresis (PFGE). PFGE had a high level of discrimination with biotype 1A isolates (Simpson's Diversity Index 0.997), but with the clinically important biotypes 2, 3 and 4, the discriminatory ability of PFGE was so low as to severely limit its usefulness (DI enterocolitica biotypes 2, 3 and 4, and inferences based on finding indistinguishable PFGE profiles among cases or between cases and sources need to be substantiated using alternative typing tools, or strong epidemiological evidence. © 2013 Blackwell Verlag GmbH.

Multilocus Sequence Typing Scheme versus Pulsed-Field Gel Electrophoresis for Typing Mycobacterium abscessus Isolates

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Machado, Gabriel Esquitini; Matsumoto, Cristianne Kayoko; Chimara, Erica; Duarte, Rafael da Silva; de Freitas, Denise; Palaci, Moises; Hadad, David Jamil; Lima, Karla Valéria Batista; Lopes, Maria Luiza; Ramos, Jesus Pais; Campos, Carlos Eduardo; Caldas, Paulo César; Heym, Beate

2014-01-01

Outbreaks of infections by rapidly growing mycobacteria following invasive procedures, such as ophthalmological, laparoscopic, arthroscopic, plastic, and cardiac surgeries, mesotherapy, and vaccination, have been detected in Brazil since 1998. Members of the Mycobacterium chelonae-Mycobacterium abscessus group have caused most of these outbreaks. As part of an epidemiological investigation, the isolates were typed by pulsed-field gel electrophoresis (PFGE). In this project, we performed a large-scale comparison of PFGE profiles with the results of a recently developed multilocus sequence typing (MLST) scheme for M. abscessus. Ninety-three isolates were analyzed, with 40 M. abscessus subsp. abscessus isolates, 47 M. abscessus subsp. bolletii isolates, and six isolates with no assigned subspecies. Forty-five isolates were obtained during five outbreaks, and 48 were sporadic isolates that were not associated with outbreaks. For MLST, seven housekeeping genes (argH, cya, glpK, gnd, murC, pta, and purH) were sequenced, and each isolate was assigned a sequence type (ST) from the combination of obtained alleles. The PFGE patterns of DraI-digested DNA were compared with the MLST results. All isolates were analyzable by both methods. Isolates from monoclonal outbreaks showed unique STs and indistinguishable or very similar PFGE patterns. Thirty-three STs and 49 unique PFGE patterns were identified among the 93 isolates. The Simpson's index of diversity values for MLST and PFGE were 0.69 and 0.93, respectively, for M. abscessus subsp. abscessus and 0.96 and 0.97, respectively, for M. abscessus subsp. bolletii. In conclusion, the MLST scheme showed 100% typeability and grouped monoclonal outbreak isolates in agreement with PFGE, but it was less discriminative than PFGE for M. abscessus. PMID:24899019

Oil field and freshwater isolates of Shewanella putrefaciens have lipopolysaccharide polyacrylamide gel profiles characteristic of marine bacteria

International Nuclear Information System (INIS)

Pickard, C.; Foght, J.M.; Pickard, M.A.; Westlake, D.W.S.

1993-01-01

The lipopolysaccharide structure of oil field and freshwater isolates of bacteria that reduce ferric iron, recently classified as strains of Shewanella putrefaciens, was analyzed using polyacrylamide gel electrophoresis and a lipopolysaccharide-specific silver-staining procedure. The results demonstrate that all the oil field and freshwater isolates examined exhibited the more hydrophobic R-type lipopolysaccharide, which has been found to be characteristic of Gram-negative marine bacteria. This hydrophobic lipopolysaccharide would confer an advantage on bacteria involved in hydrocarbon degradation by assisting their association with the surface of oil droplets. 15 refs., 1 fig

Molecular Analysis of Mycobacterium avium Isolates by Using Pulsed-Field Gel Electrophoresis and PCR

Science.gov (United States)

Pestel-Caron, Martine; Graff, Gabriel; Berthelot, Gilles; Pons, Jean-Louis; Lemeland, Jean-François

1999-01-01

Genetic relationships among 46 isolates of Mycobacterium avium recovered from 37 patients in a 2,500-bed hospital from 1993 to 1998 were assessed by pulsed-field gel electrophoresis (PFGE) and PCR amplification of genomic sequences located between the repetitive elements IS1245 and IS1311. Each technique enabled the identification of 27 to 32 different patterns among the 46 isolates, confirming that the genetic heterogeneity of M. avium strains is high in a given community. Furthermore, this retrospective analysis of sporadic isolates allowed us (i) to suggest the existence of two remanent strains in our region, (ii) to raise the question of the possibility of nosocomial acquisition of M. avium strains, and (iii) to document laboratory contamination. The methods applied in the present study were found to be useful for the typing of M. avium isolates. In general, both methods yielded similar results for both related and unrelated isolates. However, the isolates in five of the six PCR clusters were distributed among two to three PFGE patterns, suggesting that this PCR-based method may have limitations for the analysis of strains with low insertion sequence copy numbers or for resolution of extended epidemiologic relationships. PMID:10405383

Comparação entre hipoclorito de sódio e ácido peracético na inativação de E. coli, colifagos e C. perfringens em água com elevada concentração de matéria orgânica Comparison between sodium hipoclorite and peracetic acid for E. coli, coliphages and C. perfringens inactivation of high organic matter concentration water

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Jeanette Beber de Souza

2005-06-01

Full Text Available Foi realizado estudo comparativo em condições experimentais similares, entre hipoclorito de sódio e ácido peracético na desinfecção de água com elevada concentração de matéria orgânica. O conteúdo de carbono orgânico dissolvido (COD variou de 4,652 a 30,13 mgC/L para a água de estudo bruta e após a desinfecção esses valores variaram de 5,105 a 26,16 mgC/L para os ensaios com cloro e de 15,89 a 32,78 mgC/L para os ensaios com ácido peracético. O desempenho dos dois desinfetantes foi avaliado segundo a inativação de três microrganismos indicadores, Escherichia coli ATCC 11229, colifagos e Clostridium perfringens ATCC 13124 que eram previamente cultivados e inoculados à água no momento do experimento. As concentrações aplicadas de cloro e ácido peracético foram de 2,0; 3,0; 4,0 e 5,0 mg/L e os tempos de contato de 5, 10, 15 e 20 minutos. Para 3,0 mg/L de cloro aplicado, obteve-se 3 log de inativação de E. coli em 20 minutos de contato, 2,92 log de inativação de fagos em 10 minutos e 2 log de inativação de C. perfringens em 15 minutos. Os resultados dos ensaios de desinfecção com ácido peracético indicaram efetiva inativação dos microrganismos indicadores empregados, mesmo na presença de elevada concentração de matéria orgânica. Para 5,0 mg/L de ácido peracético aplicado e 15 minutos de contato, inativações de E. coli maiores que 6 log, de fagos maiores que 5 log em 20 minutos e de C. perfringens maiores que 4 log em 10 minutos de contato foram alcançadas.The research comparing the action of sodium hypochlorite and peracetic acid to disinfect drinking water with high concentration organic matter was carried out in similar conditions. The dissolved organic carbon (DOC concentration was from 4.652 to 30.13 mg/L in raw water, from 5.105 to 26.16 mg/L in water disinfected with chlorine and from 15.89 to 32.72 mg/L in water disinfected with peracetic acid. The efficiency of the two disinfectants was

Molecular Typing of Salmonella Isolates in Poultry by Pulsed-Field Gel Electrophoresis in Iran

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Narges Golab

2014-11-01

Full Text Available Background: Salmonella is one of the most widespread zoonotic enter pathogenic microorganisms found in the global food chain. Poultryand Poultry products have been identified as one of the important foodborne sources of Salmonella. Pulsed-Field Gel Electrophoresis (PFGE is a gold standard typing method for identification of Salmonella isolates during outbreaks and epidemiological investigations. Objectives: The aim of this study was to carry out molecular typing of Salmonella enterica spp. by PFGE technique. Materials and Methods: All 47 Salmonella isolates were serotyped and then subjected to PFGE. Total isolates were analyzed by means of the molecular technique XbaI PFGE. Results: In the current work, PFGE and serotyping were used to subtype 47 Salmonella isolates belonging to 22 different serotypes and derived from poultry. Thirty-nine PFGE patterns out of 47 isolates were obtained. The Discrimination Index (DI by serotyping (0.93 was lower than PFGE (DI = 0.99. Conclusions: In conclusion, molecular methods such as PFGE can be used for epidemiological characterization of Salmonella serotypes.

The effect of Artemisia annua on broiler performance, on intestinal microbiota and on the course of a Clostridium perfringens infection applying a necrotic enteritis disease model

DEFF Research Database (Denmark)

Engberg, Ricarda M; Grevsen, Kai; Ivarsen, Elise

2012-01-01

The aerial parts of the plant Artemisia annua contain essential oils having antimicrobial properties against Clostridium perfringens Type A, the causal agent for necrotic enteritis in broilers. In two experiments, the influence of increasing dietary concentrations of dried A. annua leaves (0, 5, 10...... and 20 g/kg) and n-hexane extract from fresh A. annua leaves (0, 125, 250 and 500 mg/kg) on broiler performance was investigated. Dried plant material decreased feed intake and body weight in a dose-dependent manner, and 10 and 20 g/kg diet tended to improve the feed conversion ratio. The n...... the effect of the dietary addition of dried A. annua leaves (10 g/kg on top) or n-hexane extract of A. annua (250 mg/kg) on the severity of the disease in broilers. The addition of n-hexane extract reduced the intestinal C. perfringens numbers and the severity of the disease-related small intestinal lesions...

Multilocus sequence typing scheme versus pulsed-field gel electrophoresis for typing Mycobacterium abscessus isolates.

Science.gov (United States)

Machado, Gabriel Esquitini; Matsumoto, Cristianne Kayoko; Chimara, Erica; Duarte, Rafael da Silva; de Freitas, Denise; Palaci, Moises; Hadad, David Jamil; Lima, Karla Valéria Batista; Lopes, Maria Luiza; Ramos, Jesus Pais; Campos, Carlos Eduardo; Caldas, Paulo César; Heym, Beate; Leão, Sylvia Cardoso

2014-08-01

Outbreaks of infections by rapidly growing mycobacteria following invasive procedures, such as ophthalmological, laparoscopic, arthroscopic, plastic, and cardiac surgeries, mesotherapy, and vaccination, have been detected in Brazil since 1998. Members of the Mycobacterium chelonae-Mycobacterium abscessus group have caused most of these outbreaks. As part of an epidemiological investigation, the isolates were typed by pulsed-field gel electrophoresis (PFGE). In this project, we performed a large-scale comparison of PFGE profiles with the results of a recently developed multilocus sequence typing (MLST) scheme for M. abscessus. Ninety-three isolates were analyzed, with 40 M. abscessus subsp. abscessus isolates, 47 M. abscessus subsp. bolletii isolates, and six isolates with no assigned subspecies. Forty-five isolates were obtained during five outbreaks, and 48 were sporadic isolates that were not associated with outbreaks. For MLST, seven housekeeping genes (argH, cya, glpK, gnd, murC, pta, and purH) were sequenced, and each isolate was assigned a sequence type (ST) from the combination of obtained alleles. The PFGE patterns of DraI-digested DNA were compared with the MLST results. All isolates were analyzable by both methods. Isolates from monoclonal outbreaks showed unique STs and indistinguishable or very similar PFGE patterns. Thirty-three STs and 49 unique PFGE patterns were identified among the 93 isolates. The Simpson's index of diversity values for MLST and PFGE were 0.69 and 0.93, respectively, for M. abscessus subsp. abscessus and 0.96 and 0.97, respectively, for M. abscessus subsp. bolletii. In conclusion, the MLST scheme showed 100% typeability and grouped monoclonal outbreak isolates in agreement with PFGE, but it was less discriminative than PFGE for M. abscessus. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Pseudomonas syringae pv. phaseolicola isolated from weeds in bean crop fields.

Science.gov (United States)

Fernández-Sanz, A M; Rodicio, M R; González, A J

2016-04-01

Pseudomonas syringae pv. phaseolicola, the causative agent of halo blight in common bean (Phaseolus vulgaris L.), was isolated from weeds associated with bean crops in Spain. The bacterium was recovered from Fumaria sp, Mercurialis annua, Solanum nigrum and Sonchus oleraceus. Ps. s. pv. phaseolicola had previously been isolated from leguminous plants and S. nigrum, but to our knowledge, this is the first time it was recovered from the other three species. The isolates were phenotypically and genetically characterized, and they were compared with isolates recovered from common beans. Five different genotypic profiles were detected by PmeI-PFGE, two of them being of new description. Weed isolates were as pathogenic on bean plants as bean isolates, but they were not pathogenic on S. nigrum. Regarding the survival of the pathogen in weeds, Ps. s. pv. phaseolicola was isolated from So. oleraceus 11 weeks after the end of the bean crop. These results strongly support the idea of weeds as a potential source of inoculum for halo blight in bean. It has traditionally been considered that the main source of inoculum of Pseudomonas syringae pv. phaseolicola causing halo blight disease in Phaseolus vulgaris are the bean seeds, and that the host range of the bacterium is almost restricted to leguminous plants. In this study, the bacterium was recovered from four nonleguminous weed species collected in bean fields, and its permanence in weeds for at least 11 weeks after the harvesting of the beans was demonstrated. We have also proved that the strains isolated from weeds were pathogenic on bean plants. Accordingly, the host range of Ps. s. pv. phaseolicola could be broader than previously thought and weeds appear to be acting as a reservoir of the pathogen until the next crop. © 2016 The Society for Applied Microbiology.

Microbiological and 16S rRNA analysis of sulphite-reducing clostridia from river sediments in central Italy

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Marcheggiani Stefania

2008-10-01

Full Text Available Abstract Background Microbiological indicators are commonly used in the assessment of public health risks associated with fecal contamination of freshwater ecosystems. Sediments are a reservoir of microorganisms, and can thus provide information on past pollution events, not obtainable through the testing of surface water. Moreover, pathogens present in sediment may represent future threats to human health. Clostridium perfringens, a typical colonizer of sediments, has been suggested as an alternative indicator of fecal pollution. In order to be suitable for such purpose, the microorganism should be widely distributed in contaminated environments. The objective of this study was thus to determine the composition of the anaerobic community in sediment samples of the lower Tiber basin, in central Italy, through a combined approach involving granulometric analysis of sediment samples, as well as a microbiological and molecular (16S rRNA analysis of strains. Results Granulometry showed a similar, clayey sediment composition, in most sampling sites. The microbiological method, employing, an adaptation of the standard method, proved to be effective in isolating anaerobic bacteria from the environmental matrix for the purpose of genetic analysis. Eighty-three strains of bacteria were isolated and the partial 16S rRNA gene sequenced. While biochemical analysis detected only C. perfringens strains, phylogenetic analysis indicated the presence of three clusters: C. perfringens, C. bifermentans and B. cereus, comprising eight taxa. C. perfringens, the commonest in almost all sediment sampling sites, was present in all sites, and in both seasons (seasonal sampling was carried out only along the Tiber and Aniene rivers. None of the described genetic profiles showed complete similarity with GenBank sequences. Conclusion The study underlines the value of C. perfringens as an alternative microbial indicator of fecal contamination in river sediments. This is

Microbiological and 16S rRNA analysis of sulphite-reducing clostridia from river sediments in central Italy.

Science.gov (United States)

Marcheggiani, Stefania; Iaconelli, Marcello; D'angelo, Annamaria; Pierdominici, Elio; La Rosa, Giuseppina; Muscillo, Michele; Equestre, Michele; Mancini, Laura

2008-10-08

Microbiological indicators are commonly used in the assessment of public health risks associated with fecal contamination of freshwater ecosystems. Sediments are a reservoir of microorganisms, and can thus provide information on past pollution events, not obtainable through the testing of surface water. Moreover, pathogens present in sediment may represent future threats to human health. Clostridium perfringens, a typical colonizer of sediments, has been suggested as an alternative indicator of fecal pollution. In order to be suitable for such purpose, the microorganism should be widely distributed in contaminated environments. The objective of this study was thus to determine the composition of the anaerobic community in sediment samples of the lower Tiber basin, in central Italy, through a combined approach involving granulometric analysis of sediment samples, as well as a microbiological and molecular (16S rRNA) analysis of strains. Granulometry showed a similar, clayey sediment composition, in most sampling sites. The microbiological method, employing, an adaptation of the standard method, proved to be effective in isolating anaerobic bacteria from the environmental matrix for the purpose of genetic analysis. Eighty-three strains of bacteria were isolated and the partial 16S rRNA gene sequenced. While biochemical analysis detected only C. perfringens strains, phylogenetic analysis indicated the presence of three clusters: C. perfringens, C. bifermentans and B. cereus, comprising eight taxa. C. perfringens, the commonest in almost all sediment sampling sites, was present in all sites, and in both seasons (seasonal sampling was carried out only along the Tiber and Aniene rivers). None of the described genetic profiles showed complete similarity with GenBank sequences. The study underlines the value of C. perfringens as an alternative microbial indicator of fecal contamination in river sediments. This is supported by the bacterium's presence in all sampling sites

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

OpenAIRE

Marie-Lou Gaucher; Marie-Lou Gaucher; Marie-Lou Gaucher; Gabriel G. Perron; Julie Arsenault; Ann Letellier; Martine Boulianne; Sylvain Quessy

2017-01-01

Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is k...

Spore membrane(s) as the site of damage within heated Clostridium perfringens spores.

Science.gov (United States)

Flowers, R S; Adams, D M

1976-02-01

Clostridium perfringens spores were injured by ultrahigh-temperature treatment at 105 C for 5 min. Injury was manifested as an increased sensitivity to polymyxin and neomycin. Since many of the survivors could not germinate normally the ultrahigh-temperature-treated spores were sensitized to and germinated by lysozyme. Polymyxin reportedly acts upon the cell membrane. Neomycin may inhibit protein synthesis and has surface-active properties. Injured spores were increasingly sensitive to known surface-active agents, sodium lauryl sulfate, sodium deoxycholate, and Roccal, a quaternary ammonium compound. Injured spores sensitive to polymyxin and neomycin also were osmotically fragile and died during outgrowth in a liquid medium unless the medium was supplemented with 20% sucrose, 10% dextran, or 10% polyvinylpyrrolidone. The results suggested that a spore structure destined to become cell membrane or cell wall was the site of injury. Repair of injury during outgrowth in the presence of protein, deoxyribonucleic acid, ribonucleic acid and cell wall synthesis inhibitors was consistent with this hypothesis.

Subtyping of Salmonella enterica isolated from humans and food animals using Pulsed-Field Gel Electrophoresis

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Golab, N.

2016-07-01

Full Text Available Salmonella infections are the second leading cause of zoonotic bacterial foodborne illness. Main source of infection in human is contaminated food products. The aim of this study was sub typing isolates of Salmonella enterica obtained during our previous study by Pulsed Field Gel Electrophoresis (PFGE technique. All 46 Salmonella isolates were serotyped and then subjected to PFGE. Total isolates were analyzed by means of the molecular technique XbaI PFGE. In this study, PFGE and serotyping were used to subtype 46 Salmonella isolates belonging to 27different serovars and derived from human and different food origins. Among these isolates, S. Typhimurium was found to be the most predominant serovar. 40 PFGE patterns out of 46 isolates were obtained. The Discrimination Index obtained by serotyping (DI = 0.93 was lower than PFGE (DI = 0.99. Subtyping of Salmonella enterica is very important and shows that animal origin can be one of a reservoir that potentially could be transferred to human through the food chain. In addition, results of this study also revealed that this procedure is a golden standard for genotyping of such salmonella serotypes.

In Vitro Antimicrobial Susceptibility Testing of Animal Nocardia Isolated from Field Cases of Skin Diseases

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M. A. Oyekunle

2001-03-01

Full Text Available In vitro antimicrobial tests were carried out on strains of Nocardia isolated from field cases of cutaneous nocardiosis in farm animals. Results with the disc diffusion test showed the multiresistant nature of the isolates, but 23.81 and 21.43% were sensitive to ciprofloxacin and gentamycin, respectively. The MIC mode and range for oxytetracycline were 12.5 and 3.12–25 μg/ml, respectively, while those of erythromycin were 3.12 and 0.78–6.25 μg/ml, respectively.

Cyclic Di-GMP Binding by an Assembly ATPase (PilB2) and Control of Type IV Pilin Polymerization in the Gram-Positive Pathogen Clostridium perfringens.

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Hendrick, William A; Orr, Mona W; Murray, Samantha R; Lee, Vincent T; Melville, Stephen B

2017-05-15

The Gram-positive pathogen Clostridium perfringens possesses type IV pili (TFP), which are extracellular fibers that are polymerized from a pool of pilin monomers in the cytoplasmic membrane. Two proteins that are essential for pilus functions are an assembly ATPase (PilB) and an inner membrane core protein (PilC). Two homologues each of PilB and PilC are present in C. perfringens , called PilB1/PilB2 and PilC1/PilC2, respectively, along with four pilin proteins, PilA1 to PilA4. The gene encoding PilA2, which is considered the major pilin based on previous studies, is immediately downstream of the pilB2 and pilC2 genes. Purified PilB2 had ATPase activity, bound zinc, formed hexamers even in the absence of ATP, and bound the second messenger molecule cyclic di-GMP (c-di-GMP). Circular dichroism spectroscopy of purified PilC2 indicated that it retained its predicted degree of alpha-helical secondary structure. Even though no direct interactions between PilB2 and PilC2 could be detected in vivo or in vitro even in the presence of c-di-GMP, high levels of expression of a diguanylate cyclase from C. perfringens (CPE1788) stimulated polymerization of PilA2 in a PilB2- and PilC2-dependent manner. These results suggest that PilB2 activity is controlled by c-di-GMP levels in vivo but that PilB2-PilC2 interactions are either transitory or of low affinity, in contrast to results reported previously from in vivo studies of the PilB1/PilC1 pair in which PilC1 was needed for polar localization of PilB1. This is the first biochemical characterization of a c-di-GMP-dependent assembly ATPase from a Gram-positive bacterium. IMPORTANCE Type IV pili (TFP) are protein fibers involved in important bacterial functions, including motility, adherence to surfaces and host cells, and natural transformation. All clostridia whose genomes have been sequenced show evidence of the presence of TFP. The genetically tractable species Clostridium perfringens was used to study proteins involved in

Comparison of field-collected ascovirus isolates by DNA hybridization, host range, and histopathology.

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Hamm, J J; Styer, E L; Federici, B A

1998-09-01

Six field-collected ascovirus isolates obtained from five noctuid species in the continental United States were compared with respect to the general relatedness of their DNA, host range, and histopathology. Two isolates were from Spodoptera frugiperda, and the other four were from Autographa precationis, Heliothis virescens, Helicoverpa zea, and Trichoplusia ni. DNA-DNA hybridization studies showed that the six isolates belonged to three distinct viral species, with the isolates from S. frugiperda composing one species, those from A. precationis and H. virescens a second species, and those from H. zea and T. ni a third species. The host range and histopathology of each isolate was studied in eight noctuid species, S. frugiperda, Spodoptera ornithogalli, Spodoptera exigua, Spodoptera eridania, H. virescens, H. zea, A. precationis, and Feltia subterranea. Though some variation existed between the different isolates of each viral species, distinct patterns were apparent for each. The viral species from S. frugiperda had a host range that was limited primarily to Spodoptera species and both isolates of this virus only replicated and caused significant pathology in the fat body, whereas the viral species from A. precationis and H. virescens had a much broader host range that included most of the species tested, but also had a tissue tropism primarily restricted to the fat body. The viral species from T. ni and H. zea readily infected all the hosts tested, where the principal site of replication and significant pathology was the epidermis. In many test hosts, however, this viral species also replicated and caused significant pathology in the tracheal epithelium and to a lesser extent in the fat body. Aside from contributing to knowledge of ascovirus biology, these studies indicate that DNA hybridization profiles combined with studies of host range and tissue tropism can be used as characters for defining ascovirus species. Copyright 1998 Academic Press.

Nonreciprocal propagation of light without external magnetic fields in a semiconductor waveguide isolator with a MnAs layer

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Amemiya, T. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan) and Japan Science and Techonology Agency, SORST (Japan)]. E-mail: ametomo@hotaka.t.u-tokyo.ac.jp; Shimizu, H. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Techonology Agency, SORST (Japan); Hai, P.N. [Department of Electronic Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Japan Science and Techonology Agency, SORST (Japan); Tanaka, M. [Department of Electronic Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Japan Science and Techonology Agency, SORST (Japan); Nakano, Y. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Techonology Agency, SORST (Japan)

2007-03-15

A 1.5-{mu}m, TM-mode waveguide optical isolator was developed for use in photonic integrated circuits. It consists of an InGaAlAs-based optical waveguide with a ferromagnetic MnAs layer and makes use of nonreciprocal propagation loss of light induced by the magnetized MnAs layer. With a large-remanence MnAs layer grown with the Mn-template epitaxy method, the isolator successfully showed an 8.7 dB/mm isolation ratio without external magnetic fields.

Comparative genomics of four closely related Clostridium perfringens bacteriophages reveals variable evolution among core genes with therapeutic potential

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Siragusa Gregory R

2011-06-01

Full Text Available Abstract Background Because biotechnological uses of bacteriophage gene products as alternatives to conventional antibiotics will require a thorough understanding of their genomic context, we sequenced and analyzed the genomes of four closely related phages isolated from Clostridium perfringens, an important agricultural and human pathogen. Results Phage whole-genome tetra-nucleotide signatures and proteomic tree topologies correlated closely with host phylogeny. Comparisons of our phage genomes to 26 others revealed three shared COGs; of particular interest within this core genome was an endolysin (PF01520, an N-acetylmuramoyl-L-alanine amidase and a holin (PF04531. Comparative analyses of the evolutionary history and genomic context of these common phage proteins revealed two important results: 1 strongly significant host-specific sequence variation within the endolysin, and 2 a protein domain architecture apparently unique to our phage genomes in which the endolysin is located upstream of its associated holin. Endolysin sequences from our phages were one of two very distinct genotypes distinguished by variability within the putative enzymatically-active domain. The shared or core genome was comprised of genes with multiple sequence types belonging to five pfam families, and genes belonging to 12 pfam families, including the holin genes, which were nearly identical. Conclusions Significant genomic diversity exists even among closely-related bacteriophages. Holins and endolysins represent conserved functions across divergent phage genomes and, as we demonstrate here, endolysins can have significant variability and host-specificity even among closely-related genomes. Endolysins in our phage genomes may be subject to different selective pressures than the rest of the genome. These findings may have important implications for potential biotechnological applications of phage gene products.

One-day pulsed-field gel electrophoresis protocol for rapid determination of emetic Bacillus cereus isolates.

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Kaminska, Paulina S; Fiedoruk, Krzysztof; Jankowska, Dominika; Mahillon, Jacques; Nowosad, Karol; Drewicka, Ewa; Zambrzycka, Monika; Swiecicka, Izabela

2015-04-01

Bacillus cereus, the Gram-positive and spore-forming ubiquitous bacterium, may cause emesis as the result of food intoxication with cereulide, a heat-stable emetic toxin. Rapid determination of cereulide-positive B. cereus isolates is of highest importance due to consequences of this intoxication for human health and life. Here we present a 1-day pulsed-field gel electrophoresis for emetic B. cereus isolates, which allows rapid and efficient determination of their genomic relatedness and helps determining the source of intoxication in case of outbreaks caused by these bacilli. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study the effect of stable magnetic field on the inhibition activity of Saccharomyces boulardii against pathogenic bacteria isolated from urinary tract infection

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Nada Sabah Razouqi

2017-09-01

Full Text Available An increasing trend to use probiotic and study their effects on the pathogens has been conductor where they are defined as live micro-organisms that give a health benefit to the host when ingested in sufficient quantities, including the yeast Saccharomyces boulardii In addition research show that a magnetic field (MF has a biological effect. This study aims to investigate the effects of magnetic field on the inhibitory action of Saccharomyces boulardii against bacteria isolated from urinary tract infection, Study the sensitivity of bacterial isolates to antibiotics after diagnosis by microscopic, Cultural and biochemical examinations as well as Api20 E examinations were used gram negative bacteria , Most isolates were resistant to antibiotics elected, using Well diffusion method to investigate the inhibitory action of suspension and supernatant of the yeast with and without magnetic field in four different intensities (200-300-400-500 milli Tesla. The results show that inhibitory efficacy of each was higher wish increasing the magnetic field strength and differed in their impact depending on the type of bacteria and the isolate of K.pneumoniea was the most sensitive in all experiments, and suspension was more effective

Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

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Marchand-Austin, Alex; Rawte, Prasad; Toye, Baldwin; Jamieson, Frances B; Farrell, David J; Patel, Samir N

2014-08-01

The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of

Claudins Overexpression in Ovarian Cancer: Potential Targets for Clostridium Perfringens Enterotoxin (CPE Based Diagnosis and Therapy

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Diana P. English

2013-05-01

Full Text Available Claudins are a family of tight junction proteins regulating paracellular permeability and cell polarity with different patterns of expression in benign and malignant human tissues. There are approximately 27 members of the claudin family identified to date with varying cell and tissue-specific expression. Claudins-3, -4 and -7 represent the most highly differentially expressed claudins in ovarian cancer. While their exact role in ovarian tumors is still being elucidated, these proteins are thought to be critical for ovarian cancer cell invasion/dissemination and resistance to chemotherapy. Claudin-3 and claudin-4 are the natural receptors for the Clostridium perfringens enterotoxin (CPE, a potent cytolytic toxin. These surface proteins may therefore represent attractive targets for the detection and treatment of chemotherapy-resistant ovarian cancer and other aggressive solid tumors overexpressing claudin-3 and -4 using CPE-based theranostic agents.

Generation and characterization of recombinant bivalent fusion protein r-Cpib for immunotherapy against Clostridium perfringens beta and iota toxemia.

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Das, Shreya; Majumder, Saugata; Kingston, Joseph J; Batra, Harsh V

2016-02-01

Clostridium perfringens beta (CPB) and iota (CPI) toxaemias result in some of the most lethal forms of haemorrhagic and necrotic enteritis and sudden death syndrome affecting especially neonates. While CPB enterotoxemia is one of the most common forms of clostridial enterotoxemia, CPI enterotoxemia though putatively considered to be rare is an emerging cause of concern. The similarities in clinical manifestation, gross and histopathology findings of both types of toxaemias coupled to the infrequency of CPI toxaemia might lead to symptomatic misidentification with Type C resulting in therapeutic failure due to habitual administration of CPB anti-toxin which is ineffective against CPI. Therefore in the present study, to generate a composite anti-toxin capable of neutralizing both toxaemias, a novel bivalent chimera r-Cpib was constructed by splicing the non-toxic C terminal binding regions of CPB and CPI, via a flexible glycine linker (G4S) by overlap-extension PCR. The fusion protein was characterized for its therapeutic abilities toward CPI and CPB toxin neutralizations. The r-Cpib was found to be non-toxic and could competitively inhibit binding of CPB to host cell receptors thereby reducing its cytotoxicity. Immunization of mice with r-Cpib generated specific antibodies capable of neutralizing the above toxaemias both in vitro and in vivo. Caco-2 cells exposed to a mixture of anti-r-Cpib sera and native CPI or CPB, displayed significantly superior protection against the respective toxins while passive challenge of mice with a similar mixture resulted in 83 and 91% protection against CPI and CPB respectively. Alternatively, mice exposed to a mixture of sham sera and native toxins died within 2-3 days. This work thus demonstrates r-Cpib as a novel bivalent fusion protein capable of efficient immunotherapy against C. perfringens CPI and CPB toxaemia. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantitative and Isolated Measurement of Far-Field Light Scattering by a Single Nanostructure

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Kim, Donghyeong; Jeong, Kwang-Yong; Kim, Jinhyung; Ee, Ho-Seok; Kang, Ju-Hyung; Park, Hong-Gyu; Seo, Min-Kyo

2017-11-01

Light scattering by nanostructures has facilitated research on various optical phenomena and applications by interfacing the near fields and free-propagating radiation. However, direct quantitative measurement of far-field scattering by a single nanostructure on the wavelength scale or less is highly challenging. Conventional back-focal-plane imaging covers only a limited solid angle determined by the numerical aperture of the objectives and suffers from optical aberration and distortion. Here, we present a quantitative measurement of the differential far-field scattering cross section of a single nanostructure over the full hemisphere. In goniometer-based far-field scanning with a high signal-to-noise ratio of approximately 27.4 dB, weak scattering signals are efficiently isolated and detected under total-internal-reflection illumination. Systematic measurements reveal that the total and differential scattering cross sections of a Au nanorod are determined by the plasmonic Fabry-Perot resonances and the phase-matching conditions to the free-propagating radiation, respectively. We believe that our angle-resolved far-field measurement scheme provides a way to investigate and evaluate the physical properties and performance of nano-optical materials and phenomena.

Thermal inactivation of ileal loop-reactive Clostridium perfringens type A strains in phosphate buffer and beef gravy.

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Bradshaw, J G; Peeler, J T; Twedt, R M

1977-09-01

The thermal resistance of spore crops produced from each of two ileal loop-reactive strains of Clostridium perfringens type A was determined in two suspending vehicles consisting of 0.067 M (pH 7.0) phosphate buffer and a commercial beef gravy. D115.6 values obtained in buffer and enumerated after pretreatment with sodium ethylenediaminetetraacetate and recovery in plating medium containing lysozyme were two- to threefold greater than those obtained without this treatment. D115.6 values obtained with beef gravy were less than those obtained in buffer with or without lysozyme; however, the D98.9 and D104.4 values were 1.3 to 2 times greater than those obtained in buffer with lysozyme. The z values were within the ranges reported by previous investigators.

Characterization of a Unique Class C Acid Phosphatase from Clostridium perfringens▿

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Reilly, Thomas J.; Chance, Deborah L.; Calcutt, Michael J.; Tanner, John J.; Felts, Richard L.; Waller, Stephen C.; Henzl, Michael T.; Mawhinney, Thomas P.; Ganjam, Irene K.; Fales, William H.

2009-01-01

Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was ∼31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3′ and 5′ nucleoside monophosphates at pH 6. Calculated Kms ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 μmol of Pi/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class. PMID:19363079

ENSAYO PRELIMINAR DE LA ACTIVIDAD ANTIBACTERIANA DE EXTRACTOS DE ALLIUM SATIVUM, CORIANDRUM SATIVUM, EUGENIA CARYOPHYLLATA, ORIGANUM VULGARE, ROSMARINUS OFFICINALIS Y THYMUS VULGARIS FRENTE A CLOSTRIDIUM PERFRINGENS

OpenAIRE

Ardila Q., Martha I; Vargas A., Andrés F; Pérez C., Jorge E; Mejía G., Luis F

2009-01-01

Se evaluó la actividad antibacteriana frente a Clostridium perfringens (cepa ATCC: 13124) por el método de Kirby Bauer en agar SPS de los aceites esenciales o extractos vegetales obtenidos con solventes orgánicos de diferente polaridad a partir de Allium sativum (ajo), Coriandrum sativum (cilantro), Eugenia Caryophyllata (clavo de olor), Origanum vulgare (orégano), Rosmarinus officinalis (romero) y Thymus vulgaris (tomillo), utilizando la vancomicina como control. Los extractos obtenidos por ...

Bayesian fault detection and isolation using Field Kalman Filter

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Baranowski, Jerzy; Bania, Piotr; Prasad, Indrajeet; Cong, Tian

2017-12-01

Fault detection and isolation is crucial for the efficient operation and safety of any industrial process. There is a variety of methods from all areas of data analysis employed to solve this kind of task, such as Bayesian reasoning and Kalman filter. In this paper, the authors use a discrete Field Kalman Filter (FKF) to detect and recognize faulty conditions in a system. The proposed approach, devised for stochastic linear systems, allows for analysis of faults that can be expressed both as parameter and disturbance variations. This approach is formulated for the situations when the fault catalog is known, resulting in the algorithm allowing estimation of probability values. Additionally, a variant of algorithm with greater numerical robustness is presented, based on computation of logarithmic odds. Proposed algorithm operation is illustrated with numerical examples, and both its merits and limitations are critically discussed and compared with traditional EKF.

Effects of Bacillus licheniformis on the growth performance and expression of lipid metabolism-related genes in broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis.

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Zhou, Mengjia; Zeng, Dong; Ni, Xueqin; Tu, Teng; Yin, Zhongqiong; Pan, Kangcheng; Jing, Bo

2016-03-08

Necrotic enteritis (NE), caused by Clostridium perfringens, has cost the poultry industry $2 billion in losses. This study aimed to investigate the effect of Bacillus licheniformis as dietary supplement on the growth, serum antioxidant status, and expression of lipid-metabolism genes of broiler chickens with C. perfringens-induced NE. A total of 240 one-day-old broilers were randomly grouped into four: a negative control, an NE experimental model (PC), chickens fed a diet supplemented with 30 % of fishmeal from day 14 onwards and challenged with coccidiosis vaccine (FC), and NE group supplied with feed containing 1.0 × 10(6) CFU/g B. licheniformis (BL). Body weight gain, feed conversion ratio, serum antioxidant status, and lipid-metabolism-gene expression were analyzed. In the PC group, FCR increased significantly whereas serum catalase and glutathione peroxidase activity decreased compared with NC group. Dietary B. licheniformis supplementation improved FCR and oxidative stress in experimental avian NE. Using Bacillus licheniformis as a direct-fed microbial (DFM) could also significantly upregulate catabolism-related genes, namely, peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1, in livers and changed the expression of lipid-anabolism genes. These results suggested that dietary B. licheniformis supplementation can enhance growth and antioxidant ability, as well as change the expression of genes related to fatty-acid synthesis and oxidation in the livers of NE-infected broilers.

Biodegradation of 2,4-dichlorophenoxyacetic acid by bacteria with highly antibiotic-resistant pattern isolated from wheat field soils in Kurdistan, Iran.

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Karami, Solmaz; Maleki, Afshin; Karimi, Ebrahim; Poormazaheri, Helen; Zandi, Shiva; Davari, Behrooz; Salimi, Yahya Zand; Gharibi, Fardin; Kalantar, Enayatollah

2016-12-01

Recently, there has been increasing interest to clean up the soils contaminated with herbicide. Our aim was to determine the bioremediation of 2,4-dichlorophenoxyacetic acid (2,4-D) from wheat fields which have a long history of herbicide in Sanandaj. Based on our literature survey, this study is the first report to isolate and identify antimicrobial resistant bacteria from polluted wheat field soils in Sanandaj which has the capacity to degrade 2,4-D. From 150 2,4-D-exposed soil samples, five different bacteria were isolated and identified based on biochemical tests and 16S ribosomal RNA (rRNA). Pseudomonas has been the most frequently isolated genus. By sequencing the 16S rRNA gene of the isolated bacteria, the strains were detected and identified as a member of the genus Pseudomonas sp, Entrobacter sp, Bacillus sp, Seratia sp, and Staphylococcus sp. The sequence of Sanandaj 1 isolate displayed 87% similarity with the 16S rRNA gene of a Pseudomonas sp (HE995788). Similarly, all the isolates were compared to standard strains based on 16S rRNA. Small amounts of 2,4-D could be transmitted to a depth of 10-20 cm; however, in the depth of 20-40 cm, we could not detect the 2,4-D. The isolates were resistant to various antibiotics particularly, penicillin, ampicillin, and amoxicillin.

Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from 'Marcha'.

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Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

2014-01-01

In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.

Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

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Archana Shrestha

2016-12-01

Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

An efficient thermotolerant and halophilic biosurfactant-producing bacterium isolated from Dagang oil field for MEOR application

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Wu, Langping; Richnow, Hans; Yao, Jun; Jain, Anil

2014-05-01

Dagang Oil field (Petro China Company Limited) is one of the most productive oil fields in China. In this study, 34 biosurfactant-producing strains were isolated and cultured from petroleum reservoir of Dagang oil field, using haemolytic assay and the qualitative oil-displacement test. On the basis of 16S rDNA analysis, the isolates were closely related to the species in genus Pseudomonas, Staphylococcus and Bacillus. One of the isolates identified as Bacillus subtilis BS2 were selected for further study. This bacterium was able to produce a type of biosurfactant with excessive foam-forming properties at 37ºC as well as at higher temperature of 55ºC. The biosurfactant produced by the strain BS2 could reduce the surface tension of the culture broth from 70.87 mN/m to 28.97 mN/m after 8 days of incubation at 37ºC and to 36.15 mN/m after 20 days of incubation at 55ºC, respectively. The biosurfactant showed stability at high temperature (up to 120ºC), a wide range of pH (2 to 12) and salt concentrations (up to 12%) offering potential for biotechnology. Fourier transform infrared (FT-IR) spectrum of extracted biosurfactant tentatively characterized the produced biosurfactant as glycolipid derivative. Elemental analysis of the biosurfactant by energy dispersive X-ray spectroscopy (EDS) reveals that the biosurfactant was anionic in nature. 15 days of biodegradation of crude oil suggested a preferential usage of n-alkane upon microbial metabolism of BS2 as a carbon substrate and consequently also for the synthesis of biosurfactants. Core flood studies for oil release indicated 9.6% of additional oil recovery over water flooding at 37ºC and 7.2% of additional oil recovery at 55 ºC. Strain BS2 was characterized as an efficient biosurfactant-producing, thermotolerant and halophillic bacterium and has the potential for application for microbial enhanced oil recovery (MEOR) through water flooding in China's oil fields even in situ as adapted to reservoir chemistry and

SYMBIODINIUM ISOLATES FROM STONY CORAL: ISOLATION, GROWTH CHARACTERISTICS AND EFFECTS OF UV IRRADIATION

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Symbiodinium spp. Isolates from Stony Coral: Isolation, Growth Characteristics and Effects of UV Irradiation (Abstract). J. Phycol. 37(3):42-43.Symbiodinium species were isolated from Montipora capitata, Acropora palmata and two field samples of Porites porites. Cultures ...

Optimization of culture conditions to improve the expression level of beta1–epsilon toxin of Clostridium perfringens type B in Escherichia coli

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Chuwen Lin

2016-03-01

Full Text Available The detoxified beta1–epsilon (β1–ϵ toxin protein of Clostridium perfringens type B provides protection from C. perfringens types B, C and D infections. Acetate is the primary by-product from the cell growth and expression of β1–ϵ protein. In the present study, the effects of pH and dissolved oxygen (DO on the expression of β1--ϵ protein were investigated. Two-stage pH and DO control strategies were developed for the expression of β1–ϵ protein. The obtained results indicated that higher cell density and concentration of β1--ϵ protein, and lower accumulation of acetate were obtained when pH was maintained at a constant level of 6.5 (0–6 h and 7.0 (6–16 h, and the DO level was maintained at 60% (0–6 h and 30% (6–16 h. Furthermore, the impact of intermittent, DO feedback, pH feedback and glucose-stat feeding on the expression of β1–ϵ protein were studied. By using the DO feedback feeding, combined with the stage control of pH (6.5 for 0–6 h, 7.0 for 6–16 h and DO (60% for 0–6 h, 30% for 6–16 h, the highest cell density of 2.045 (absorbance at 600 nm and a β1–ϵ protein concentration of 63.24 mg/L were obtained, and the accumulation of acetate decreased to 0.872 g/L.

Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from ‘Marcha’

Science.gov (United States)

Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

2014-01-01

In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative. PMID:25477937

Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field

DEFF Research Database (Denmark)

Tanaka, Reiji; Kawaichi, Satoshi; Nishimura, Hiroshi

2006-01-01

A novel thermophilic bacterium, strain KW1T, was isolated from a coastal hydrothermal field on the Satsuma Peninsula, Kagoshima Prefecture, Japan. The variably Gram-stained cells were motile rods with flagella, did not form spores and proliferated at 52-78°C (optimum, 70°C), pH 5-8 (optimum, pH 7...

Variable stiffness and damping MR isolator

Energy Technology Data Exchange (ETDEWEB)

Zhang, X Z; Wang, X Y; Li, W H; Kostidis, K [University of Wollongong, School of Mechanical, Materials and Mechatronic Engineering, NSW 2522 (Australia)], E-mail: weihuali@uow.edu.au

2009-02-01

This paper presents the development of a magnetorheological (MR) fluid-based variable stiffness and damping isolator for vibration suppressions. The MR fluid isolator used a sole MR control unit to achieve the variable stiffness and damping in stepless and relative large scope. A mathematical model of the isolator was derived, and a prototype of the MR fluid isolator was fabricated and its dynamic behavior was measured in vibration under various applied magnetic fields. The parameters of the model under various magnetic fields were identified and the dynamic performances of isolator were evaluated.

Epidemiologic analysis of sporadic Salmonella typhi isolates and those from outbreaks by pulsed-field gel electrophoresis.

Science.gov (United States)

Thong, K L; Cheong, Y M; Puthucheary, S; Koh, C L; Pang, T

1994-05-01

Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.

Molecular analysis of Leptospira spp. isolated from humans by restriction fragment length polymorphism, real-time PCR and pulsed-field gel electrophoresis.

Science.gov (United States)

Turk, Nenad; Milas, Zoran; Mojcec, Vesna; Ruzic-Sabljic, Eva; Staresina, Vilim; Stritof, Zrinka; Habus, Josipa; Postic, Daniele

2009-11-01

A total of 17 Leptospira clinical strains isolated from humans in Croatia were serologically and genetically analysed. For serovar identification, the microscopic agglutination test (MAT) and pulsed-field gel electrophoresis (PFGE) were used. To identify isolates on genomic species level, PCR-based restriction fragment length polymorphism (RFLP) and real-time PCR were performed. MAT revealed the following serogroup affinities: Grippotyphosa (seven isolates), Icterohaemorrhagiae (eight isolates) and Javanica (two isolates). RFLP of PCR products from a 331-bp-long fragment of rrs (16S rRNA gene) digested with endonucleases MnlI and DdeI and real-time PCR revealed three Leptospira genomic species. Grippotyphosa isolates belonged to Leptospira kirschneri, Icterohaemorrhagiae isolates to Leptospira interrogans and Javanica isolates to Leptospira borgpetersenii. Genomic DNA from 17 leptospiral isolates was digested with NotI and SgrAI restriction enzymes and analysed by PFGE. Results showed that seven isolates have the same binding pattern to serovar Grippotyphosa, eight isolates to serovar Icterohaemorrhagiae and two isolates to serovar Poi. Results demonstrate the diversity of leptospires circulating in Croatia. We point out the usefulness of a combination of PFGE, RFLP and real-time PCR as appropriate molecular methods in molecular analysis of leptospires.

Incipient Fault Detection and Isolation of Field Devices in Nuclear Power Systems Using Principal Component Analysis

International Nuclear Information System (INIS)

Kaistha, Nitin; Upadhyaya, Belle R.

2001-01-01

An integrated method for the detection and isolation of incipient faults in common field devices, such as sensors and actuators, using plant operational data is presented. The approach is based on the premise that data for normal operation lie on a surface and abnormal situations lead to deviations from the surface in a particular way. Statistically significant deviations from the surface result in the detection of faults, and the characteristic directions of deviations are used for isolation of one or more faults from the set of typical faults. Principal component analysis (PCA), a multivariate data-driven technique, is used to capture the relationships in the data and fit a hyperplane to the data. The fault direction for each of the scenarios is obtained using the singular value decomposition on the state and control function prediction errors, and fault isolation is then accomplished from projections on the fault directions. This approach is demonstrated for a simulated pressurized water reactor steam generator system and for a laboratory process control system under single device fault conditions. Enhanced fault isolation capability is also illustrated by incorporating realistic nonlinear terms in the PCA data matrix

Enhanced discrimination of highly clonal ST22-methicillin-resistant Staphylococcus aureus IV isolates achieved by combining spa, dru, and pulsed-field gel electrophoresis typing data.

LENUS (Irish Health Repository)

Shore, Anna C

2010-05-01

ST22-methicillin-resistant Staphylococcus aureus type IV (ST22-MRSA-IV) is endemic in Irish hospitals and is designated antibiogram-resistogram type-pulsed-field group (AR-PFG) 06-01. Isolates of this highly clonal strain exhibit limited numbers of pulsed-field gel electrophoresis (PFGE) patterns and spa types. This study investigated whether combining PFGE and spa typing with DNA sequencing of the staphylococcal cassette chromosome mec element (SCCmec)-associated direct repeat unit (dru typing) would improve isolate discrimination. A total of 173 MRSA isolates recovered in one Irish hospital during periods in 2007 and 2008 were investigated using antibiogram-resistogram (AR), PFGE, spa, dru, and SCCmec typing. Isolates representative of each of the 17 pulsed-field group 01 (PFG-01) spa types identified underwent multilocus sequence typing, and all isolates were ST22. Ninety-seven percent of isolates (168 of 173) exhibited AR-PFG 06-01 or closely related AR patterns, and 163 of these isolates harbored SCCmec type IVh. The combination of PFGE, spa, and dru typing methods significantly improved discrimination of the 168 PFG-01 isolates, yielding 65 type combinations with a Simpson\\'s index of diversity (SID) of 96.53, compared to (i) pairwise combinations of spa and dru typing, spa and PFGE typing, and dru and PFGE typing, which yielded 37, 44, and 43 type combinations with SIDs of 90.84, 91.00, and 93.57, respectively, or (ii) individual spa, dru, and PFGE typing methods, which yielded 17, 17, and 21 types with SIDs of 66.9, 77.83, and 81.34, respectively. Analysis of epidemiological information for a subset of PFG-01 isolates validated the relationships inferred using combined PFGE, spa, and dru typing data. This approach significantly enhances discrimination of ST22-MRSA-IV isolates and could be applied to epidemiological investigations of other highly clonal MRSA strains.

Biodegradation of isoproturon by Pseudoxanthomonas sp. isolated from herbicide-treated wheat fields of Tarai agro-ecosystem, Pantnagar.

Science.gov (United States)

Giri, Krishna; Pandey, Shailseh; Kumar, Rajesh; Rai, J P N

2016-12-01

A gram-negative, rod-shaped, isoproturon (IPU) utilizing bacterium was isolated from herbicide-applied wheat fields of Tarai agro-ecosystem, Pantnagar. The phylogenetic sequence analysis based on 16S rRNA sequence revealed that the isolate could be a distinct species within the genus Pseudomonas. The isolate was a close relative of Pseudoxanthomonas japonensis (95 % similarity) and designated as K2. The bacterial isolate showed positive reaction for oxidase, catalase, and 20 carbohydrates using KB009 Part A and B HiCarbohydrate™ Kit. Degradation experiments were conducted using 200 mg l -1 initial IPU as a source of carbon at different pH and temperatures. Maximum IPU degradation by K2 was observed at pH 7.0 and 30 °C, while least degradation at 6.5 pH and 25 °C. Addition of dextrose along with IPU as an auxiliary carbon source increased IPU degradation by 4.72 %, as compared to the IPU degradation without dextrose under optimum conditions. 4-isopropylaniline was detected as a degradation by-product in the medium. The present study demonstrated the IPU metabolizing capacity of a novel bacterial isolate K2 that can be a better choice for the remediation of IPU-contaminated sites.

Characterization of vancomycin-resistant and vancomycin-susceptible Enterococcus faecium isolates from humans, chickens and pigs by RiboPrinting and pulsed-field gel electrophoresis

DEFF Research Database (Denmark)

Hammerum, Anette Marie; Fussing, Vivian; Aarestrup, Frank Møller

2000-01-01

Forty-eight vancomycin-resistant and 35 vancomycin-sensitive Danish Enterococcus faecium isolates obtained from pigs, chickens and humans, as well as the human vanA reference isolate BM4147, were characterized by EcoRI RiboPrinting and Smal pulsed-field gel electrophoresis. RiboPrinting of the 84...

Improved protocol for isolation of Campylobacter spp. from retail broiler meat and use of pulsed field gel electrophoresis for the typing of isolates.

Science.gov (United States)

Oyarzabal, Omar A; Williams, Aretha; Zhou, Ping; Samadpour, Mansour

2013-10-01

To improve the detection of Campylobacter spp. in retail broiler meat, a reference method (R subsamples) based on the enrichment of 25 g of meat in Bolton broth at 42°C under microaerobiosis was compared with an alternative method (A subsamples) consisting in the rinsing of meat samples for 30s in buffered peptone water with antimicrobials with incubation at 42°C under aerobiosis. One piece of meat (breasts, tenderloins and thighs) was rinse in experiment 1 (A1) and two pieces in experiment 2 (A2). Campylobacter spp. were isolated on agar plates and identified by PCR. Retail samples in Alabama had less prevalence (P ≤ 0.05) than samples in the state of Washington. The percentage of positive was higher (P ≤ 0.05) in A than in R subsamples and rinsing two pieces of meat yielded the highest percentage of positive subsamples. R subsamples showed variations in the prevalence by product. However, A subsamples had similar prevalence of positives among products compare to the result from reference method. More Campylobacter coli isolates were collected in A2 subsamples. Pulse field gel electrophoresis (PFGE) was used as subtyping method to study the genome similarity among the isolates from all methods. A larger diversity of isolates were detected by PFGE in A2 subsamples. Denaturing gradient gel electrophoresis analysis suggested that the initial bacterial populations of the meat samples impact the final bacterial profile after enrichment. Rinsing broiler meats was less time consuming, required less sample preparation and was more sensitive than the reference method for the isolation of naturally occurring Campylobacter spp. This new method could help with epidemiological and intervention studies to control Campylobacter spp. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of Fusarium isolates from asparagus fields in southwestern Ontario and influence of soil organic amendments on Fusarium crown and root rot.

Science.gov (United States)

Borrego-Benjumea, Ana; Basallote-Ureba, María J; Melero-Vara, José M; Abbasi, Pervaiz A

2014-04-01

Fusarium crown and root rot (FCRR) of asparagus has a complex etiology with several soilborne Fusarium spp. as causal agents. Ninety-three Fusarium isolates, obtained from plant and soil samples collected from commercial asparagus fields in southwestern Ontario with a history of FCRR, were identified as Fusarium oxysporum (65.5%), F. proliferatum (18.3%), F. solani (6.4%), F. acuminatum (6.4%), and F. redolens (3.2%) based on morphological or cultural characteristics and polymerase chain reaction (PCR) analysis with species-specific primers. The intersimple-sequence repeat PCR analysis of the field isolates revealed considerable variability among the isolates belonging to different Fusarium spp. In the in vitro pathogenicity screening tests, 50% of the field isolates were pathogenic to asparagus, and 22% of the isolates caused the most severe symptoms on asparagus. The management of FCRR with soil organic amendments of pelleted poultry manure (PPM), olive residue compost, and fish emulsion was evaluated in a greenhouse using three asparagus cultivars of different susceptibility in soils infested with two of the pathogenic isolates (F. oxysporum Fo-1.5 and F. solani Fs-1.12). Lower FCRR symptom severity and higher plant weights were observed for most treatments on 'Jersey Giant' and 'Grande' but not on 'Mary Washington'. On all three cultivars, 1% PPM consistently reduced FCRR severity by 42 to 96% and increased plant weights by 77 to 152% compared with the Fusarium control treatment. Populations of Fusarium and total bacteria were enumerated after 1, 3, 7, and 14 days of soil amendment. In amended soils, the population of Fusarium spp. gradually decreased while the population of total culturable bacteria increased. These results indicate that soil organic amendments, especially PPM, can decrease disease severity and promote plant growth, possibly by decreasing pathogen population and enhancing bacterial activity in the soil.

The HIV-1 V3 domain on field isolates: participation in generation of escape virus in vivo and accessibility to neutralizing antibodies

DEFF Research Database (Denmark)

Arendrup, M; Akerblom, L; Heegaard, P M

1995-01-01

The V3 domain is highly variable and induces HIV neutralizing antibodies (NA). Here we addressed the issues of 1) the participation of mutations in V3 in generation of neutralization resistant escape virus in vivo and 2) the applicability of synthetic V3 peptides corresponding to field isolates...... patterns against V3 peptides corresponding to sequential primary and escape field isolates, with the strongest reactivity against late isolated escape virus. These observations suggest that the neutralization epitope was influenced by the appearance of mutations. When used as immunogen in rabbits, V3...... to induce neutralizing immune sera. Seven peptides corresponding to the V3 region of primary and escape virus from 3 HIV-1 infected patients were synthesized and used for antibody (Abs) studies and immunizations. The anti-V3 Abs titre in patient serum was generally low against peptides corresponding...

Degradation of petroleum hydrocarbons by oil field isolated bacterial ...

African Journals Online (AJOL)

A mixed consortium was prepared with 15 bacteria isolated by enrichment technique from the sample collected from an oil contaminated site. This consortium was incubated with crude oil to investigate the metabolic capability of bacteria. The degradation efficiency of the isolates in consortium was checked with 2% crude oil ...

POPULATION SYNTHESIS OF YOUNG ISOLATED NEUTRON STARS: THE EFFECT OF FALLBACK DISK ACCRETION AND MAGNETIC FIELD EVOLUTION

International Nuclear Information System (INIS)

Fu, Lei; Li, Xiang-Dong

2013-01-01

The spin evolution of isolated neutron stars (NSs) is dominated by their magnetic fields. The measured braking indices of young NSs show that the spin-down mechanism due to magnetic dipole radiation with constant magnetic fields is inadequate. Assuming that the NS magnetic field is buried by supernova fallback matter and re-emerges after accretion stops, we carry out a Monte Carlo simulation of the evolution of young NSs, and show that most of the pulsars have braking indices ranging from –1 to 3. The results are compatible with the observational data of NSs associated with supernova remnants. They also suggest that the initial spin periods of NSs might occupy a relatively wide range

Membrane solid-phase extraction: Field application for isolation of polycyclic aromatic hydrocarbons from water samples

International Nuclear Information System (INIS)

Furlong, E.T.; Koleis, J.C.; Gates, P.M.

1995-01-01

Solid-phase extraction (SPE) membranes (M-SPE) were used to isolate microgram-per-liter to nanogram-per-liter quantities of polycyclic aromatic hydrocarbons (PAH) in 4- to 8-liter ground-water samples from a crude-oil-contaminated ground-water site near Bemidji, Minnesota. The M-SPE method was evaluated (1) under laboratory conditions using reagent water fortified with individual PAH at 1.23 micrograms per liter, and (2) at the Bemidji site. At the site, ground-water samples were processed and PAH isolated using a M-SPE system connected directly to the well pump. Following sample isolation, all M-SPE samples were extracted using dichloromethane and analyzed by gas chromatography-mass spectrometry with selected-ion monitoring. Operationally, the M-SPE method provided a simple means to isolate PAH on site at the wellhead, particularly for anoxic water samples. Acceptable recoveries, ranging from 56 to over 100 percent, were observed for lower molecular weight PAH (naphthalene to pyrene) using the M-SPE method. Recoveries using M-SPE were somewhat lower, but reproducible, for higher molecular weight PAH (chrysene to benzo[ghi]perylene), ranging from 18 to 56 percent. M-SPE provides the capability to collect and field isolate PAH from a sufficiently large number of samples to identify environmental chemical processes occurring at individual compound concentrations of 50 to 1,200 nanograms per liter. Using M-SPE, the potential for facilitated transport of PAH by in situ-derived dissolved organic carbon (DOC) was evaluated at the site. Plots comparing DOC and PAH concentrations indicate that PAH concentrations increase exponentially with linear increases in DOC concentrations

Biodegradation of Textile Dyes by Fungi Isolated from North Indian Field Soil

Directory of Open Access Journals (Sweden)

Arshi Shahid

2013-07-01

Full Text Available In this study one azo dye "Congo red", two triphenymethane dyes "Crystal violet" and "Methylene blue" have been selected for biodegradation using three soil fungal isolates A. niger, F. oxysporum and T. lignorum. These fungal strains were isolated from field soil. Three methods were selected for biodegradation, viz. agar overlay and liquid media methods; stationary and shaking conditions at 25°C. The experiment was conducted for 10 days and the results were periodically observed. Aspergillus niger decolorized maximum Congo red (74.07% followed by Crystal violet (33.82% and Methylene blue (22.44% under liquid medium (stationary condition. Whereas, under same conditions, T. lignorum decolorized maximum crystal violet (92.7%, Methylene blue (48.3% and Congo red (35.25%. Use of T. lignorum as dye bio degrader or decolorizer has been done first time in this study. Fusarium oxysporum performed better under shaking conditions compared to stationary and overlay method. It can be concluded that among soil fungus T. lignorum could be used as efficient dye decolorizer especially for crystal violet and A. niger for Congo red. The excellent performance of T. lignorum and F. oxysporum in the biodegradation of textile dyes of different chemical structures reinforces the potential of these fungi for environmental decontamination similar to white rot fungi.

A novel Hsp70 inhibitor prevents cell intoxication with the actin ADP-ribosylating Clostridium perfringens iota toxin

Science.gov (United States)

Ernst, Katharina; Liebscher, Markus; Mathea, Sebastian; Granzhan, Anton; Schmid, Johannes; Popoff, Michel R.; Ihmels, Heiko; Barth, Holger; Schiene-Fischer, Cordelia

2016-01-01

Hsp70 family proteins are folding helper proteins involved in a wide variety of cellular pathways. Members of this family interact with key factors in signal transduction, transcription, cell-cycle control, and stress response. Here, we developed the first Hsp70 low molecular weight inhibitor specifically targeting the peptide binding site of human Hsp70. After demonstrating that the inhibitor modulates the Hsp70 function in the cell, we used the inhibitor to show for the first time that the stress-inducible chaperone Hsp70 functions as molecular component for entry of a bacterial protein toxin into mammalian cells. Pharmacological inhibition of Hsp70 protected cells from intoxication with the binary actin ADP-ribosylating iota toxin from Clostridium perfringens, the prototype of a family of enterotoxins from pathogenic Clostridia and inhibited translocation of its enzyme component across cell membranes into the cytosol. This finding offers a starting point for novel therapeutic strategies against certain bacterial toxins. PMID:26839186

Comprehensive study of proteasome inhibitors against Plasmodium falciparum laboratory strains and field isolates from Gabon

Directory of Open Access Journals (Sweden)

Kremsner Peter G

2008-09-01

Full Text Available Abstract Background The emergence and spread of Plasmodium falciparum resistance to almost all available antimalarial drugs necessitates the search for new chemotherapeutic compounds. The ubiquitin/proteasome system plays a major role in overall protein turnover, especially in fast dividing eukaryotic cells including plasmodia. Previous studies show that the 20S proteasome is expressed and catalytically active in plasmodia and treatment with proteasome inhibitors arrests parasite growth. This is the first comprehensive screening of proteasome inhibitors with different chemical modes of action against laboratory strains of P. falciparum. Subsequently, a selection of inhibitors was tested in field isolates from Lambaréné, Gabon. Methods Epoxomicin, YU101, YU102, MG132, MG115, Z-L3-VS, Ada-Ahx3-L3-VS, lactacystin, bortezomib (Velcade®, gliotoxin, PR11 and PR39 were tested and compared to chloroquine- and artesunate-activities in a standardized in vitro drug susceptibility assay against P. falciparum laboratory strains 3D7, D10 and Dd2. Freshly obtained field isolates from Lambaréné, Gabon, were used to measure the activity of chloroquine, artesunate, epoxomicin, MG132, lactacystin and bortezomib. Parasite growth was detected through histidine-rich protein 2 (HRP2 production. Raw data were fitted by a four-parameter logistic model and individual inhibitory concentrations (50%, 90%, and 99% were calculated. Results Amongst all proteasome inhibitors tested, epoxomicin showed the highest activity in chloroquine-susceptible (IC50: 6.8 nM [3D7], 1.7 nM [D10] and in chloroquine-resistant laboratory strains (IC50: 10.4 nM [Dd2] as well as in field isolates (IC50: 8.5 nM. The comparator drug artesunate was even more active (IC50: 1.0 nM, whereas all strains were chloroquine-resistant (IC50: 113 nM. Conclusion The peptide α',β'-epoxyketone epoxomicin is highly active against P. falciparum regardless the grade of the parasite's chloroquine

Virus isolation vs RT-PCR: which method is more successful in detecting VHSV and IHNV in fish tissue sampled under field conditions?

DEFF Research Database (Denmark)

Knüsel, R.; Bergmann, S. M.; Einer-Jensen, Katja

2007-01-01

in Switzerland. Compared to SPNT, the RT-PCR method detected, as with virus isolation, a much lower number of positive cases; reasons for this discrepancy are discussed. Our results indicate that RT-PCR can not only be successfully applied in field surveys, but may also be slightly more sensitive than virus......This study compared the results of reverse transcription-polymerase chain reaction (RT-PCR) and traditional virus isolation on cell culture in detection of viral haemorrhagic septicaemia virus (VHSV) and infectious haematopoietic necrosis virus (IHNV). RT-PCR was used for 172 tissue sample pools...... (total of 859 fish) originating from a field survey on the occurrence of VHSV and IHNV in farmed and wild salmonids in Switzerland. These samples represented all sites with fish that were either identified as virus-positive by means of virus isolation (three sites, four positive tissue sample pools) and...

Aeromicrobium ginsengisoli sp. nov., isolated from a ginseng field.

Science.gov (United States)

Kim, Myung Kyum; Park, Min-Ju; Im, Wan-Taek; Yang, Deok-Chun

2008-09-01

Strain Gsoil 098(T), a Gram-positive, non-spore-forming, non-motile coccus, was isolated from soil from a ginseng field in South Korea and characterized in order to determine its taxonomic position. 16S rRNA gene sequence analysis revealed that strain Gsoil 098(T) belongs to the family Nocardioidaceae, and the highest degrees of sequence similarity were found with Aeromicrobium marinum T2(T) (99.0%), A. panaciterrae Gsoil 161(T) (98.9%), A. alkaliterrae KSL-107(T) (98.4%), A. fastidiosum KCTC 9576(T) (98.1%) and A. erythreum NRRL B-3381(T) (97.5%). Chemotaxonomic analysis revealed that strain Gsoil 098(T) possesses menaquinone MK-9(H(4)) and predominant fatty acids C(16 : 0), 10-methyl C(18:0) and C(18:0). DNA-DNA hybridization results and physiological and biochemical tests clearly demonstrated that strain Gsoil 098(T) represents a distinct species. Based on these data, Gsoil 098(T) (=KCTC 19207(T) =JCM 14732(T) =GBS 39(T)) should be classified as the type strain of a novel Aeromicrobium species, for which the name Aeromicrobium ginsengisoli sp. nov. is proposed.

A Field Experiment to Assess the Rate of Infestation in Honey Bee Populations of Two Metarhizium Anisopliae Isolates on Varroa Destructor (Acari: Mesostigmata

Directory of Open Access Journals (Sweden)

Khodadad Pirali-kheirabadi

2013-03-01

Full Text Available Background: The protective effect of two isolates of an entomopathogenic fungus, Metarhizium anisopliae (DEMI 002 and Iran 437C on the adult stage of Varroa destructor was evaluated in comparison with fluvalinate strips in the field.Methods: A total of 12 honey bee colonies were provided from an apiculture farm. The selected hives were divided into 4 groups (3 hives per group. The first group was the control, treated with distilled water. The other two groups were exposed to different fungi (M. anisopliae isolates DEMI 002 and Iran 437C and the last group was treated with one strip of fluvalinate per colony. The number of fallen mites was counted using sticky traps during a 6-day period, six days before and after treatments. A fungal suspension at a concentration of 5× 106 conidia/mL was sprayed onto the frames and the number of fallen mites was counted.Results: Metarhizium anisopliae DEMI 002 and Iran 437C isolates were as effective (i.e., caused as much mite fall as the fluvalinate strip in controlling bee colonies than no treatment.Conclusion: Both M. anisopliae isolates are promising candidates as agents in the control of Varroa mites under field conditions. Isolate DEMI 002 can be considered as a possible non-chemical biocontrol agent for controlling bee infestation with V. destructor in the field. In order to substantiate this hypothesis, tests are currently being performed using larger colonies and larger doses than tested in the present study in our beekeeping.

Isolated electrostatic structures observed throughout the Cluster orbit: relationship to magnetic field strength

Directory of Open Access Journals (Sweden)

J. S. Pickett

2004-07-01

Full Text Available Isolated electrostatic structures are observed throughout much of the 4R_E by 19.6R_E Cluster orbit. These structures are observed in the Wideband plasma wave instrument's waveform data as bipolar pulses (one positive and one negative peak in the electric field amplitude and tripolar pulses (two positive and one negative peak, or vice versa. These structures are observed at all of the boundary layers, in the solar wind and magnetosheath, and along auroral field lines at 4.5-6.5R_E. Using the Wideband waveform data from the various Cluster spacecraft we have carried out a survey of the amplitudes and time durations of these structures and how these quantities vary with the local magnetic field strength. Such a survey has not been carried out before, and it reveals certain characteristics of solitary structures in a finite magnetic field, a topic still inadequately addressed by theories. We find that there is a broad range of electric field amplitudes at any specific magnetic field strength, and there is a general trend for the electric field amplitudes to increase as the strength of the magnetic field increases over a range of 5 to 500nT. We provide a possible explanation for this trend that relates to the structures being Bernstein-Greene-Kruskal mode solitary waves. There is no corresponding dependence of the duration of the structures on the magnetic field strength, although a plot of these two quantities reveals the unexpected result that with the exception of the magnetosheath, all of the time durations for all of the other regions are comparable, whereas the magnetosheath time durations clearly are in a different category of much smaller time duration. We speculate that this implies that the structures are much smaller in size. The distinctly different pulse durations for the magnetosheath pulses indicate the possibility that the pulses are generated by a mechanism which is different

Isolated electrostatic structures observed throughout the Cluster orbit: relationship to magnetic field strength

Directory of Open Access Journals (Sweden)

J. S. Pickett

2004-07-01

Full Text Available Isolated electrostatic structures are observed throughout much of the 4RE by 19.6RE Cluster orbit. These structures are observed in the Wideband plasma wave instrument's waveform data as bipolar pulses (one positive and one negative peak in the electric field amplitude and tripolar pulses (two positive and one negative peak, or vice versa. These structures are observed at all of the boundary layers, in the solar wind and magnetosheath, and along auroral field lines at 4.5-6.5RE. Using the Wideband waveform data from the various Cluster spacecraft we have carried out a survey of the amplitudes and time durations of these structures and how these quantities vary with the local magnetic field strength. Such a survey has not been carried out before, and it reveals certain characteristics of solitary structures in a finite magnetic field, a topic still inadequately addressed by theories. We find that there is a broad range of electric field amplitudes at any specific magnetic field strength, and there is a general trend for the electric field amplitudes to increase as the strength of the magnetic field increases over a range of 5 to 500nT. We provide a possible explanation for this trend that relates to the structures being Bernstein-Greene-Kruskal mode solitary waves. There is no corresponding dependence of the duration of the structures on the magnetic field strength, although a plot of these two quantities reveals the unexpected result that with the exception of the magnetosheath, all of the time durations for all of the other regions are comparable, whereas the magnetosheath time durations clearly are in a different category of much smaller time duration. We speculate that this implies that the structures are much smaller in size. The distinctly different pulse durations for the magnetosheath pulses indicate the possibility that the pulses are generated by a mechanism which is different from the mechanism operating in other regions.

Pulsed-Field Gel Electrophoresis Analysis of Bordetella pertussis Isolates Circulating in Europe from 1998 to 2009

Science.gov (United States)

Advani, Abdolreza; Hallander, Hans O.; Dalby, Tine; Krogfelt, Karen Angeliki; Guiso, Nicole; Njamkepo, Elisabeth; von Könnig, Carl Heinz Wirsing; Riffelmann, Marion; Mooi, Frits R.; Sandven, Per; Lutyńska, Anna; Fry, Norman K.; Mertsola, Jussi

2013-01-01

Between 1998 and 2009, Bordetella pertussis clinical isolates were collected during three periods, i.e., 1998 to 2001 (n = 102), 2004 to 2005 (n = 154), and 2007 to 2009 (n = 140), from nine countries with distinct vaccination programs, i.e., Denmark, Finland, France, Germany, The Netherlands, Norway, Poland, Sweden, and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according to standardized recommendations for epidemiological typing of B. pertussis. There were 81 different PFGE profiles, five of which (BpSR3, BpSR5, BpSR10, BpSR11, and BpSR12) were observed in 61% of the 396 isolates and shown to be predominant in almost all countries. The major profile, BpSR11, showed a decreasing trend from 25% to 30% in 1998 to 2005 to 13% in 2007 to 2009, and there were increases in BpSR3 and BpSR10 from 0% and 8% to 21% and 22%, respectively. One difference between these profiles is that BpSR11 contains isolates harboring the fim3-2 allele and BpSR3 and BpSR10 contain isolates harboring the fim3-1 allele. The total proportion of the five predominant profiles increased from 44% in 1998 to 2001 to 63% in 2004 to 2005 to 70% in 2007 to 2009. In conclusion, common PFGE profiles were identified in B. pertussis populations circulating in European countries with different vaccination programs and different vaccine coverages. These prevalent isolates contain the novel pertussis toxin promoter ptxP3 allele. However, there is evidence for diversifying selection between ptxP3 strains characterized by distinct PFGE profiles. This work shows that, even within a relatively short time span of 10 years, successful isolates which spread through Europe and cause large shifts in B. pertussis populations may emerge. PMID:23175253

Exploring MALDI-TOF MS approach for a rapid identification of Mycobacterium avium ssp. paratuberculosis field isolates.

Science.gov (United States)

Ricchi, M; Mazzarelli, A; Piscini, A; Di Caro, A; Cannas, A; Leo, S; Russo, S; Arrigoni, N

2017-03-01

The aim of the study was to explore the suitability of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for a rapid and correct identification of Mycobacterium avium ssp. paratuberculosis (MAP) field isolates. MALDI-TOF MS approach is becoming one of the most popular tests for the identification of intact bacterial cells which has been shown to be fast and reliable. For this purpose, 36 MAP field isolates were analysed through MALDI-TOF MS and the spectra compared with two different databases: one provided by the vendor of the system employed (Biotyper ver. 3·0; Bruker Daltonics) and a homemade database containing spectra from both tuberculous and nontuberculous Mycobacteria. Moreover, principal component analysis procedure was employed to confirm the ability of MALDI-TOF MS to discriminate between very closely related subspecies. Our results suggest MAP can be differentiated from other Mycobacterium species, both when the species are very close (M. intracellulare) and when belonging to different subspecies (M. avium ssp. avium and M. avium ssp. silvaticum). The procedure applied is fast, easy to perform, and achieves an earlier accurate species identification of MAP and nontuberculous Mycobacteria in comparison to other procedures. The gold standard test for the diagnosis of paratuberculosis is still isolation of MAP by cultural methods, but additional assays, such as qPCR and subculturing for determination of mycobactin dependency are required to confirm its identification. We have provided here evidence pertaining to the usefulness of MALDI-TOF MS approach for a rapid identification of this mycobacterium among other members of M. avium complex. © 2016 The Society for Applied Microbiology.

Survival of Salmonella spp. and fecal indicator bacteria in Vietnamese biogas digesters receiving pig slurry

DEFF Research Database (Denmark)

Luu, Huong Quynh; Forslund, Anita; Madsen, Henry

2014-01-01

. and the fecal indicator bacteria, enterococci, E. coli, and spores of Clostridium perfringens in biogas digesters operated by small-scale Vietnamese pig farmers. The serovar and antimicrobial susceptibility of the Salmonella spp. isolated were also established. The study was conducted in 12 farms (6 farms...

Efficacy of Pulsed-Field Gel Electrophoresis and Repetitive Element Sequence-Based PCR in Typing of Salmonella Isolates from Assam, India.

Science.gov (United States)

Gogoi, Purnima; Borah, Probodh; Hussain, Iftikar; Das, Leena; Hazarika, Girin; Tamuly, Shantanu; Barkalita, Luit Moni

2018-05-01

A total of 12 Salmonella isolates belonging to different serovars, viz , Salmonella enterica serovar Enteritidis ( n = 4), Salmonella enterica serovar Weltevreden ( n = 4), Salmonella enterica serovar Newport ( n = 1), Salmonella enterica serovar Litchifield ( n = 1), and untypeable strains ( n = 2) were isolated from 332 diarrheic fecal samples collected from animals, birds, and humans. Of the two molecular typing methods applied, viz , repetitive element sequence-based PCR (REP-PCR) and pulsed-field gel electrophoresis (PFGE), PFGE could clearly differentiate the strains belonging to different serovars as well as differentiate between strains of the same serovar with respect to their source of isolation, whereas REP-PCR could not differentiate between strains of the same serovar. Thus, it can be suggested that PFGE is more useful and appropriate for molecular typing of Salmonella isolates during epidemiological investigations than REP-PCR. Copyright © 2018 American Society for Microbiology.

Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves

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Bonnie R. Valgaeren

2015-07-01

Full Text Available Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin.

Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves

Science.gov (United States)

Valgaeren, Bonnie R.; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

2015-01-01

Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin. PMID:26184311

Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves.

Science.gov (United States)

Valgaeren, Bonnie R; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

2015-07-10

Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin.

1H, 15N and 13C backbone and side-chain resonance assignments of a family 32 carbohydrate-binding module from the Clostridium perfringens NagH.

Science.gov (United States)

Grondin, Julie M; Chitayat, Seth; Ficko-Blean, Elizabeth; Boraston, Alisdair B; Smith, Steven P

2012-10-01

The Gram-positive anaerobe Clostridium perfringens is an opportunistic bacterial pathogen that secretes a battery of enzymes involved in glycan degradation. These glycoside hydrolases are thought to be involved in turnover of mucosal layer glycans, and in the spread of major toxins commonly associated with the development of gastrointestinal diseases and gas gangrene in humans. These enzymes employ multi-modularity and carbohydrate-binding function to degrade extracellular eukaryotic host sugars. Here, we report the full (1)H, (15)N and (13)C chemical shift resonance assignments of the first family 32 carbohydrate-binding module from NagH, a secreted family 84 glycoside hydrolase.

Isolation and Characterization of Mobile Genetic Elements from Microbial Assemblages Obtained from the Field Research Center Site

Energy Technology Data Exchange (ETDEWEB)

Patricia Sobecky; Cassie Hodges; Kerri Lafferty; Mike Humphreys; Melanie Raimondo; Kristin Tuttle; Tamar Barkay

2004-03-17

Considerable knowledge has been gained from the intensive study of a relatively limited group of bacterial plasmids. Recent efforts have begun to focus on the characterization of, at the molecular level, plasmid populations and associated mobile genetic elements (e.g., transposons, integrons) occurring in a wider range of aquatic and terrestrial habitats. Surprisingly, however, little information is available regarding the incidence and distribution of mobile genetic elements extant in contaminated subsurface environments. Such studies will provide greater knowledge on the ecology of plasmids and their contributions to the genetic plasticity (and adaptation) of naturally occurring subsurface microbial communities. We requested soil cores from the DOE NABIR Field Research Center (FRC) located on the Oak Ridge Reservation. The cores, received in February 2003, were sampled from four areas on the Oak Ridge Site: Area 1, Area 2, Area 3 (representing contaminated subsurface locales) and the background reference sites. The average core length (24 in) was subdivided into three profiles and soil pH and moisture content were determined. Uranium concentration was also determined in bulk samples. Replicate aliquots were fixed for total cell counts and for bacterial isolation. Four different isolation media were used to culture aerobic and facultative microbes from these four study areas. Colony forming units ranged from a minimum of 100 per gram soil to a maximum of 10,000 irrespective of media composition used. The vast majority of cultured subsurface isolates were gram-positive isolates and plasmid characterization was conducted per methods routinely used in the Sobecky laboratory. The percentage of plasmid incidence ranged from 10% to 60% of all isolates tested. This frequency appears to be somewhat higher than the incidence of plasmids we have observed in other habitats and we are increasing the number of isolates screened to confirm this observation. We are also

Sabin Vaccine Reversion in the Field: a Comprehensive Analysis of Sabin-Like Poliovirus Isolates in Nigeria.

Science.gov (United States)

Famulare, Michael; Chang, Stewart; Iber, Jane; Zhao, Kun; Adeniji, Johnson A; Bukbuk, David; Baba, Marycelin; Behrend, Matthew; Burns, Cara C; Oberste, M Steven

2016-01-01

To assess the dynamics of genetic reversion of live poliovirus vaccine in humans, we studied molecular evolution in Sabin-like poliovirus isolates from Nigerian acute flaccid paralysis cases obtained from routine surveillance. We employed a novel modeling approach to infer substitution and recombination rates from whole-genome sequences and information about poliovirus infection dynamics and the individual vaccination history. We confirmed observations from a recent vaccine trial that VP1 substitution rates are increased for Sabin-like isolates relative to the rate for the wild type due to increased nonsynonymous substitution rates. We also inferred substitution rates for attenuating nucleotides and confirmed that reversion can occur in days to weeks after vaccination. We combine our observations for Sabin-like virus evolution with the molecular clock for VP1 of circulating wild-type strains to infer that the mean time from the initiating vaccine dose to the earliest detection of circulating vaccine-derived poliovirus (cVDPV) is 300 days for Sabin-like virus type 1, 210 days for Sabin-like virus type 2, and 390 days for Sabin-like virus type 3. Phylogenetic relationships indicated transient local transmission of Sabin-like virus type 3 and, possibly, Sabin-like virus type 1 during periods of low wild polio incidence. Comparison of Sabin-like virus recombinants with known Nigerian vaccine-derived poliovirus recombinants shows that while recombination with non-Sabin enteroviruses is associated with cVDPV, the recombination rates are similar for Sabin isolate-Sabin isolate and Sabin isolate-non-Sabin enterovirus recombination after accounting for the time from dosing to the time of detection. Our study provides a comprehensive picture of the evolutionary dynamics of the oral polio vaccine in the field. The global polio eradication effort has completed its 26th year. Despite success in eliminating wild poliovirus from most of the world, polio persists in populations

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

Science.gov (United States)

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

2015-03-01

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 β-barrel of 14 amphipathic β-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. Copyright © 2014 Elsevier B.V. All rights reserved.

Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin.

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Alexander Belyy

Full Text Available Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia.

Mucilaginibacter pedocola sp. nov., isolated from a heavy-metal-contaminated paddy field.

Science.gov (United States)

Tang, Jingwei; Huang, Jing; Qiao, Zixu; Wang, Rui; Wang, Gejiao

2016-10-01

Strain TBZ30T was isolated from soil of a heavy-metal-contaminated paddy field. Cells of strain TBZ30T were Gram-staining-negative, rod-shaped, non-motile and non-spore-forming. The isolate was strictly aerobic, pink-pigmented, catalase- and oxidase-positive and produced exopolysaccharides. On the basis of 16S rRNA gene phylogeny, strain TBZ30T belonged to the genus Mucilaginibacter and appeared most closely related to Mucilaginibacter gynuensis YC7003T (95.8 %), Mucilaginibacter litoreus BR-18T (95.4 %) and Mucilaginibacter mallensis MP1X4T (95.4 %). Strain TBZ30T contained menaquinone-7 as the only ubiquinone. The main cellular fatty acids included summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), iso-C15 : 0, C16 : 0, iso-C17 : 0 3-OH and C16 : 1ω5c. The polar lipids were phosphatidylethanolamine, an unidentified phospholipid, two unidentified aminophospholipids, four unidentified aminolipids, three unidentified lipids and two unidentified glycolipids. The genomic DNA G+C content was 49.0 mol%. On the basis of polyphasic taxonomy analyses, strain TBZ30T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter pedocola sp. nov. is proposed. The type strain is TBZ30T (=KCTC 42833T=CCTCC AB 2015301T).

TU-H-BRA-02: The Physics of Magnetic Field Isolation in a Novel Compact Linear Accelerator Based MRI-Guided Radiation Therapy System

Energy Technology Data Exchange (ETDEWEB)

Low, D [UCLA, Los Angeles, CA (United States); Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States); Shvartsman, S; Chmielewski, T; Fought, G; Sharma, A; Dempsey, J [ViewRay, Inc., Oakwood Village, OH (United States)

2016-06-15

Purpose: To develop a method for isolating the MRI magnetic field from field-sensitive linear accelerator components at distances close to isocenter. Methods: A MRI-guided radiation therapy system has been designed that integrates a linear accelerator with simultaneous MR imaging. In order to accomplish this, the magnetron, port circulator, radiofrequency waveguide, gun driver, and linear accelerator needed to be placed in locations with low magnetic fields. The system was also required to be compact, so moving these components far from the main magnetic field and isocenter was not an option. The magnetic field sensitive components (exclusive of the waveguide) were placed in coaxial steel sleeves that were electrically and mechanically isolated and whose thickness and placement were optimized using E&M modeling software. Six sets of sleeves were placed 60° apart, 85 cm from isocenter. The Faraday effect occurs when the direction of propagation is parallel to the magnetic RF field component, rotating the RF polarization, subsequently diminishing RF power. The Faraday effect was avoided by orienting the waveguides such that the magnetic field RF component was parallel to the magnetic field. Results: The magnetic field within the shields was measured to be less than 40 Gauss, significantly below the amount needed for the magnetron and port circulator. Additional mu-metal was employed to reduce the magnetic field at the linear accelerator to less than 1 Gauss. The orientation of the RF waveguides allowed the RT transport with minimal loss and reflection. Conclusion: One of the major challenges in designing a compact linear accelerator based MRI-guided radiation therapy system, that of creating low magnetic field environments for the magnetic-field sensitive components, has been solved. The measured magnetic fields are sufficiently small to enable system integration. This work supported by ViewRay, Inc.

TU-H-BRA-02: The Physics of Magnetic Field Isolation in a Novel Compact Linear Accelerator Based MRI-Guided Radiation Therapy System

International Nuclear Information System (INIS)

Low, D; Mutic, S; Shvartsman, S; Chmielewski, T; Fought, G; Sharma, A; Dempsey, J

2016-01-01

Purpose: To develop a method for isolating the MRI magnetic field from field-sensitive linear accelerator components at distances close to isocenter. Methods: A MRI-guided radiation therapy system has been designed that integrates a linear accelerator with simultaneous MR imaging. In order to accomplish this, the magnetron, port circulator, radiofrequency waveguide, gun driver, and linear accelerator needed to be placed in locations with low magnetic fields. The system was also required to be compact, so moving these components far from the main magnetic field and isocenter was not an option. The magnetic field sensitive components (exclusive of the waveguide) were placed in coaxial steel sleeves that were electrically and mechanically isolated and whose thickness and placement were optimized using E&M modeling software. Six sets of sleeves were placed 60° apart, 85 cm from isocenter. The Faraday effect occurs when the direction of propagation is parallel to the magnetic RF field component, rotating the RF polarization, subsequently diminishing RF power. The Faraday effect was avoided by orienting the waveguides such that the magnetic field RF component was parallel to the magnetic field. Results: The magnetic field within the shields was measured to be less than 40 Gauss, significantly below the amount needed for the magnetron and port circulator. Additional mu-metal was employed to reduce the magnetic field at the linear accelerator to less than 1 Gauss. The orientation of the RF waveguides allowed the RT transport with minimal loss and reflection. Conclusion: One of the major challenges in designing a compact linear accelerator based MRI-guided radiation therapy system, that of creating low magnetic field environments for the magnetic-field sensitive components, has been solved. The measured magnetic fields are sufficiently small to enable system integration. This work supported by ViewRay, Inc.

The Prevalence of ESBL Isolates of Acinetobacter baumannii Using Pulsed-Field Gel Electrophoresis

Directory of Open Access Journals (Sweden)

Parviz Mohajeri

2014-12-01

Full Text Available Background: Antibiotics such as fluoroquinolones are used for treating infections caused by Gram-negative bacteria, including Acinetobacter baumannii strains some time have extended-spectrum β-lactamase (ESBL, but ESBL production is rather rare. Resistance to fluoroquinolones antibiotics is mediated by lactamases and other mechanisms of resistance. The aim of the present study was to investigate of the prevalence of ESBL production and clonal relatedness of A. baumannii in Iran. Materials and Methods: A. baumannii isolates identified from patients at hospitals in Kermanshah, Iran, were studied. The double disk method was used for detection of ESBL production. The susceptibility to different antibiotics was determined by the disk diffusion method (CLSI. Clonal relatedness was determined by pulsed-field gel electrophoresis (PFGE and processed by Bionumerics 7.0 software. Statistical analyses were performed using SPSS-16.0. Results: This study showed high prevalence of resistance to ampicillin and cefpodoxim (98.1 and 92.3%. Fifty-two of the 84 isolates were identified as ESBL producers. Only colistin and tigecycline remained active against all isolates tested. The PFGE identified eight distinct pulsotypes: A (N=9, B (N=10, C (N=2, D (N=5, E (N=9, F (N=15, G (N=1 and H (N=1. The PFGE profiles A, B and F were believed to be endemic (specially clone F that was dominant across different wards of the hospitals and appeared to be endemic in the ICU, emergency, pediatric and infection area throughout the years. Conclusion: Early and timely detection of ESBL-producing A. baumannii clones is useful for preventing their spread within the hospital. PFGE analysis is helpful for detection of common strains in different wards and prevention of further spread of these pulsotypes to other hospital environment.

A complex array of Hpr consensus DNA recognition sequences proximal to the enterotoxin gene in Clostridium perfringens type A.

Science.gov (United States)

Brynestad, S; Iwanejko, L A; Stewart, G S; Granum, P E

1994-01-01

Enterotoxin production in Clostridium perfringens is both strain dependent and sporulation associated. Underlying these phenotypic observations must lie a genetic and molecular explanation and the principal keys will be held within the DNA sequence both upstream and downstream of the structural gene cpe. In accordance with the above we have sequenced 4.1 kbp of DNA upstream of cpe in the type strain NCTC 8239. A region of DNA extending up to 1.5 kb 5' to cpe is conserved in all enterotoxin-positive strains. This region contains a putative ORF with substantial homology to an ORF in the Salmonella typhimurium IS200 insertion element and, in addition, contains multiple perfect consensus DNA-binding sequences for the Bacillus subtilis transition state regulator Hpr. The detailed structural elements revealed by the sequence analysis are presented and used to develop a new perspective on the molecular basis of enterotoxin production in this important food-poisoning bacterium.

High-resolution melt PCR analysis for rapid identification of Chlamydia abortus live vaccine strain 1B among C. abortus strains and field isolates.

Science.gov (United States)

Vorimore, Fabien; Cavanna, Noémie; Vicari, Nadia; Magnino, Simone; Willems, Hermann; Rodolakis, Annie; Siarkou, Victoria I; Laroucau, Karine

2012-09-01

We describe a novel high-resolution melt assay that clearly differentiates Chlamydia abortus live vaccine strain 1B from field C. abortus strains and field wild-type isolates based on previously described single nucleotide polymorphisms. This modern genotyping technique is inexpensive, easy to use, and less time-consuming than PCR-RFLP. Copyright © 2012 Elsevier B.V. All rights reserved.

Isolation, identification and field tests of the sex pheromone of the carambola fruit borer, Eucosma notanthes.

Science.gov (United States)

Hung, C C; Hwang, J S; Hung, M D; Yen, Y P; Hou, R F

2001-09-01

Two components, (Z)-8-dodecenyl acetate (Z8-12:Ac) and (Z)-8-dodecenol (Z8-12:OH), were isolated from sex pheromone glands of the carambola fruit borer, Eucosma notanthes, and were identified by GC, and GC-MS, chemical derivatization, and comparison of retention times. The ratio of the alcohol to acetate in the sex pheromone extracts was 2.7. However, synthetic mixtures (1 mg) in ratios ranging from 0.5 to 1.5 were more effective than other blends in trapping male moths in field tests.

Study of the virulence and cross-neutralization capability of recent porcine parvovirus field isolates and vaccine viruses in experimentally infected pregnant gilts.

Science.gov (United States)

Zeeuw, E J L; Leinecker, N; Herwig, V; Selbitz, H-J; Truyen, U

2007-02-01

The pathogenicity of two recent German field isolates of Porcine parvovirus (PPV-27a and PPV-143a) and two vaccine viruses [PPV-NADL-2 and PPV-IDT (MSV)], which are used for the production of inactivated vaccines, was investigated by inoculation of pregnant sows at day 40 of gestation. Post-infection sera of these sows as well as antisera prepared in rabbits by immunization with the four above-mentioned PPV isolates and with the virulent strain PPV-Challenge (Engl.) were tested for their homologous and heterologous neutralization activities. All antisera had high neutralization activity against the vaccine viruses, the PPV-Challenge (Engl.) virus and PPV-143a, but much lower activity against PPV-27a. These results suggest that PPV-27a represents a new antigenic variant or type of PPV and vaccines based on the established vaccine viruses may not be fully protective against this field isolate. PPV-27a has been characterized based on the amino acid sequences of the capsid protein as a member of a new and distinct PPV cluster (Zimmermann et al., 2006). Interestingly, the homologous neutralizing antibody titres of the sera of all three pigs and both rabbits inoculated or immunized with PPV-27a were 100- to 1000-fold lower than the heterologous titres against any of the other viruses. The low homologous neutralizing antibody titres suggest a possible, yet undefined, immune escape mechanism of this PPV isolate.

Isolation, identification of antagonistic rhizobacterial strains obtained from chickpea (cicer arietinum l.) field and their in-vitro evaluation against fungal root pathogens

International Nuclear Information System (INIS)

Shahzaman, S.; Haq, I.U.; Mukhtar, T.; Naeem, M.

2015-01-01

Plant growth promoting rhizobacteria (PGPR), are associated with roots, found in the rhizosphere and can directly or indirectly enhance the plant growth. In this study soil was collected from rhizosphere of chickpea fields of different areas of Rawalpindi division of Pakistan. PGPR were isolated, screened and characterized. Eight isolates of rhizobacteria (RHA, RPG, RFJ, RC, RTR, RT and RK) were isolated from Rawalpindi division and were characterized. The antagonistic activity of these PGPR isolates against root infecting fungi (Fusarium oxysporum and Verticillium spp.,) was done and production of indole acetic acid (IAA), siderophore and P-solubilization was evaluated. The isolates RHA, RPG, RFJ, RC, RRD and RT were found to be positive in producing siderophore, IAA and P-solubilization. Furthermore, most of the isolates showed antifungal activity against Fusarium oxysporum, and Verticillium spp. The rhizobacterial isolates RHA, RPG, RFJ, RC, RRD, RTR, RT and RK were used as bio-inoculants that might be beneficial for chickpea cultivation as the rhizobacterial isolates possessed the plant growth promoting characters i.e. siderophore, IAA production, phosphate solubilization. In in vitro tests, Pseudomonas sp. and Bacillus spp. inhibited the mycelial growth of the fungal root pathogens. The isolates (RHA and RPG) also significantly increased (60-70%) seed germination, shoot length, root length of the chickpea. The incidence of fungi was reduced by the colonization of RHA and RPG which enhanced the seedling vigor index and seed germination. The observations revealed that isolates RHA and RPG is quite effective to reduce the fungal root infection in greenhouse, and also increases seed yields significantly. These rhizobacterial isolates appear to be efficient yield increasing as well as effective biocontrol agent against fungal root pathogen. (author)

Pulsed-Field Gel Electrophoresis characterization of Listeria monocytogenes isolates from cheese manufacturing plants in São Paulo, Brazil.

Science.gov (United States)

Barancelli, Giovana V; Camargo, Tarsila M; Gagliardi, Natália G; Porto, Ernani; Souza, Roberto A; Campioni, Fabio; Falcão, Juliana P; Hofer, Ernesto; Cruz, Adriano G; Oliveira, Carlos A F

2014-03-03

This study aimed to evaluate the occurrence of Listeria monocytogenes in cheese and in the environment of three small-scale dairy plants (A, B, C) located in the Northern region state of São Paulo, Brazil, and to characterize the isolates using conventional serotyping and PFGE. A total of 393 samples were collected and analyzed from October 2008 to September 2009. From these, 136 came from dairy plant A, where only L. seeligeri was isolated. In dairy plant B, 136 samples were analyzed, and L. innocua, L. seeligeri and L. welshimeri were isolated together with L. monocytogenes. In dairy plant C, 121 samples were analyzed, and L. monocytogenes and L. innocua were isolated. Cheese from dairy plants B and C were contaminated with Listeria spp, with L. innocua being found in Minas frescal cheese from both dairy plants, and L. innocua and L. monocytogenes in Prato cheese from dairy plant C. A total of 85 L. monocytogenes isolates were classified in 3 serotypes: 1/2b, 1/2c, and 4b, with predominance of serotype 4b in both dairy plants. The 85 isolates found in the dairy plants were characterized by genomic macrorestriction using ApaI and AscI with Pulsed Field Gel Electrophoresis (PFGE). Macrorestriction yielded 30 different pulsotypes. The presence of indistinguishable profiles repeatedly isolated during a 12-month period indicated the persistence of L. monocytogenes in dairy plants B and C, which were more than 100 km away from each other. Brine used in dairy plant C contained more than one L. monocytogenes lineage. The routes of contamination were identified in plants B and C, and highlighted the importance of using molecular techniques and serotyping to track L. monocytogenes sources of contamination, distribution, and routes of contamination in dairy plants, and to develop improved control strategies for L. monocytogenes in dairy plants and dairy products. Copyright © 2013 Elsevier B.V. All rights reserved.

Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using Chilean field isolates of Botrytis cinerea

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JUAN GONZÁLEZ

2006-01-01

Full Text Available One of the fungal pathogens that causes more agriculture damage is Botrytis cinerea. Botrytis is a constant threat to crops because the fungus infects a wide range of host species, both native and cultivated. Furthermore, Botrytis persists on plant debris in and on the soil. Some of the most serious diseases caused by Botrytis include gray mold on vegetables and fruits, such as grapes and strawberries. Botrytis also causes secondary soft rot of fruits and vegetables during storage, transit and at the market. In many plant-pathogen interactions, resistance often is associated with the deposition of callose, accumulation of autofluorescent compounds, the synthesis and accumulation of salicylic acid as well as pathogenesis-related proteins. Arabidopsis thaliana has been used as a plant model to study plant-pathogen interaction. The genome of Arabidopsis has been completely sequenced and this plant serves as a good genetic and molecular model. In this study, we demonstrate that Chilean field isolates infect Arabidopsis thaliana and that Arabidopsis subsequently activates several defense response mechanisms associated with a hypersensitive response. Furthermore, we propose that Arabidopsis may be used as a model host species to analyze the diversity associated with infectivity among populations of Botrytis cinerea field isolates

Univariate real root isolation in an extension field

DEFF Research Database (Denmark)

Strzebonski, Adam; Tsigaridas, Elias

2011-01-01

on the polynomial of the input. We compute improved separation bounds for the roots and we prove that they are optimal, under mild assumptions. For isolating the real roots we consider a modified Sturm algorithm, and a modified version of Descartes' algorithm introduced by Sagraloff. For the former we prove...

Application of Pulsed Field Gel Electrophoresis for Study of Genetic Diversity in Mycobacterium tuberculosis Strains Isolated From Tuberculosis Patients.

Science.gov (United States)

Khosravi, Azar Dokht; Vatani, Shideh; Feizabadi, Mohammad Mehdi; Abasi Montazeri, Effat; Jolodar, Abbas

2014-05-01

Mycobacterium tuberculosis genotyping can effectively improve tuberculosis (TB) control programs by controlling disease transmission. Pulsed field gel electrophoresis (PFGE) is a particularly powerful tool for determination of clonal identity of bacteria providing information for understanding and controlling the spread of disease. The aim of present study was to investigate the genetic diversity of M. tuberculosis strains in Khuzestan province by the PFGE technique. In total, 80 M. tuberculosis positive cultures were obtained from tuberculosis patients. PFGE was performed on 60 PCR-confirmed isolates by using DraI and XbaI restriction enzymes according to standard protocols. Plugs containing digested DNA were then loaded on agarose gels and run using contour-clamped homogenous electric fields. Fifty distinct DNA banding patterns were obtained by digestion of DNA with DraI and 38 DNA banding patterns by digestion with XbaI restriction enzymes. The patterns comprised of 17 different clusters in which cluster I was the major one, containing six strains. Three clusters contained three strains each and the 13 remaining clusters comprised of two strains each. Digestion with DraI yielded 15-20 DNA fragments with 50-485 kb size, while digestion by XbaI produced DNA fragments with a size smaller than 50-242 kb. Despite the ability of PFGE for study of genetic diversity of many mycobacterial species and it being considered as a robust and useful tool, in this study we only found a 15% epidemiological relationship amongst the isolates. Thus, for higher discrimination of genotypic clusters among M. tuberculosis clinical isolates, the application of more sophisticated complementary techniques is required.

Molecular characterization of Mycoplasma synoviae isolates from commercial chickens in Iran

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Pourbakhsh

2014-05-01

Full Text Available Detection of Mycoplasma synoviae (MS by culture and polymerase chain reaction (PCR has been reported from commercial chicken farms in different provinces of Iran. In some reports the phylogenetic analysis of MS isolates based on 16S rRNA and variable lipoprotein hemagglutinin (vlhA genes have been carried out. The PCR product containing partial 16S rRNA genes of Iranain isolates was sequenced, and compared with 16S rRNA gene of MS sequences which were available in GenBank. Variations, polymorphisms, and differences between nucleotides of all isolates were observed. Phylogenetic analysis of these sequences showed that all MS isolates from Iran were most closely related to sequences of MS from Brazil. Sequence analysis of the N-terminal end of the hemagglutinin encoding gene vlhA were also used as an alternative for the detection and initial typing of field strains of MS in commercial poultry. The results showed that there was a complete concordance between all Iranian isolates nucleotide sequence and the 5́-vlhA region sequence remained unchanged in all MS isolates and demonstrated differentiation between Iranian isolates and live commercial MS-H vaccine strain. More recently, the single-copy domain of the conserved region of vlhA gene in MS was sequenced, analyzed and verified to type MS field isolates in Iran and live vaccine MS-H strain. In addition, a restriction fragment length polymorphism (RFLP method was established based on single nucleotide polymorphism that existed in all field isolates of Iran to differentiate between these field isolates and MS-H. This PCR-RFLP method allowed differentiating all MS field isolates from the vaccine strain.

Experimental study and modeling of a novel magnetorheological elastomer isolator

International Nuclear Information System (INIS)

Yang, Jian; Li, Weihua; Sun, Shuaishuai; Du, Haiping; Li, Yancheng; Li, Jianchun; Deng, H X

2013-01-01

This paper reports an experimental setup aiming at evaluating the performance of a newly designed magnetorheological elastomer (MRE) seismic isolator. As a further effort to explore the field-dependent stiffness/damping properties of the MRE isolator, a series of experimental testing were conducted. Based upon the analysis of the experimental responses and the characteristics of the MRE isolator, a new model that is capable of reproducing the unique MRE isolator dynamics behaviors is proposed. The validation results verify the model’s effectiveness to portray the MRE isolator. A study on the field-dependent parameters is then provided to make the model valid with fluctuating magnetic fields. To fully explore the mechanism of the proposed model, an investigation relating the dependence of the proposed model on every parameter is carried out. (technical note)

Microarray-based comparative genomic profiling of reference strains and selected Canadian field isolates of Actinobacillus pleuropneumoniae

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MacInnes Janet I

2009-02-01

Full Text Available Abstract Background Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is a highly contagious respiratory pathogen that causes severe losses to the swine industry worldwide. Current commercially-available vaccines are of limited value because they do not induce cross-serovar immunity and do not prevent development of the carrier state. Microarray-based comparative genomic hybridizations (M-CGH were used to estimate whole genomic diversity of representative Actinobacillus pleuropneumoniae strains. Our goal was to identify conserved genes, especially those predicted to encode outer membrane proteins and lipoproteins because of their potential for the development of more effective vaccines. Results Using hierarchical clustering, our M-CGH results showed that the majority of the genes in the genome of the serovar 5 A. pleuropneumoniae L20 strain were conserved in the reference strains of all 15 serovars and in representative field isolates. Fifty-eight conserved genes predicted to encode for outer membrane proteins or lipoproteins were identified. As well, there were several clusters of diverged or absent genes including those associated with capsule biosynthesis, toxin production as well as genes typically associated with mobile elements. Conclusion Although A. pleuropneumoniae strains are essentially clonal, M-CGH analysis of the reference strains of the fifteen serovars and representative field isolates revealed several classes of genes that were divergent or absent. Not surprisingly, these included genes associated with capsule biosynthesis as the capsule is associated with sero-specificity. Several of the conserved genes were identified as candidates for vaccine development, and we conclude that M-CGH is a valuable tool for reverse vaccinology.

Genetic Diversity of Plasmodium falciparum Field Isolates in Central Sudan Inferred by PCR Genotyping of Merozoite Surface Protein 1 and 2.

Science.gov (United States)

Hamid, Muzamil M Abdel; Mohammed, Sara B; El Hassan, Ibrahim M

2013-02-01

Characterization of Plasmodium falciparum diversity is commonly achieved by amplification of the polymorphic regions of the merozoite surface proteins 1 (MSP1) and 2 (MSP2) genes. The present study aimed to determine the allelic variants distribution of MSP1 and MSP2 and multiplicity of infection in P. falciparum field isolates from Kosti, central Sudan, an area characterized by seasonal malaria transmission. Total 121 samples (N = 121) were collected during a cross-sectional survey between March and April 2003. DNA was extracted and MSP1 and MSP2 polymorphic loci were genotyped. The total number of alleles identified in MSP1 block 2 was 11, while 16 alleles were observed in MSP2 block 3. In MSP1, RO33 was found to be the predominant allelic type, carried alone or in combination with MAD20 and K1 types, whereas FC27 family was the most prevalent in MSP2. Sixty two percent of isolates had multiple genotypes and the overall mean multiplicity of infection was 1.93 (CI 95% 1.66-2.20). Age correlated with parasite density (P = 0.017). In addition, a positive correlation was observed between parasite densities and the number of alleles (P = 0.022). Genetic diversity in P. falciparum field isolates in central Sudan was high and consisted of multiple clones.

Growth of non-toxigenic Clostridium botulinum mutant LNT01 in cooked beef: One-step kinetic analysis and comparison with C. sporogenes and C. perfringens.

Science.gov (United States)

Huang, Lihan

2018-05-01

The objective of this study was to investigate the growth kinetics of Clostridium botulinum LNT01, a non-toxigenic mutant of C. botulinum 62A, in cooked ground beef. The spores of C. botulinum LNT01 were inoculated to ground beef and incubated anaerobically under different temperature conditions to observe growth and develop growth curves. A one-step kinetic analysis method was used to analyze the growth curves simultaneously to minimize the global residual error. The data analysis was performed using the USDA IPMP-Global Fit, with the Huang model as the primary model and the cardinal parameters model as the secondary model. The results of data analysis showed that the minimum, optimum, and maximum growth temperatures of this mutant are 11.5, 36.4, and 44.3 °C, and the estimated optimum specific growth rate is 0.633 ln CFU/g per h, or 0.275 log CFU/g per h. The maximum cell density is 7.84 log CFU/g. The models and kinetic parameters were validated using additional isothermal and dynamic growth curves. The resulting residual errors of validation followed a Laplace distribution, with about 60% of the residual errors within ±0.5 log CFU/g of experimental observations, suggesting that the models could predict the growth of C. botulinum LNT01 in ground beef with reasonable accuracy. Comparing with C. perfringens, C. botulinum LNT01 grows at much slower rates and with much longer lag times. Its growth kinetics is also very similar to C. sporogenes in ground beef. The results of computer simulation using kinetic models showed that, while prolific growth of C. perfringens may occur in ground beef during cooling, no growth of C. botulinum LNT01 or C. sporogenes would occur under the same cooling conditions. The models developed in this study may be used for prediction of the growth and risk assessments of proteolytic C. botulinum in cooked meats. Published by Elsevier Ltd.

Isolation of radiation resistant fungal strains from highly radioactive field

International Nuclear Information System (INIS)

Adam, Y.M.; Aziz, N.H.; Attaby, H.S.H.

1995-01-01

This study examined the radiation resistance of fungal flora isolated from the hot-lab around the radiation sources, cobalt 137 and radium 226 . The predominant mould species were: Aspergillus flavus, A. Niger, penicillium chrysogenum, cladosporium herbarum, fusarium oxysporum and alternaria citri. The D 10 values of F. Oxysporum; 2.00 KGy, A. Flavus; 1.40 KGy, P. chrysogenum; 1.15 KGy, and A. citri; 0.95 KGy, are about 1.67, 3.10, 1.92 and 1.36 folds as the D 1 0 values of the same isolates recovered from soil

In vitro antibiotic susceptibility of Dutch Mycoplasma synoviae field isolates originating from joint lesions and the respiratory tract of commercial poultry

OpenAIRE

2008-01-01

Abstract The in vitro susceptibility of 17 Dutch Mycoplasma synoviae field isolates, 3 originating from joint pathology and 14 from the respiratory tract of commercial poultry, for enrofloxacin, difloxacin, doxycycline, tylosin and tilmicosin was examined. The M. synoviae ATCC 25204 was included as a control strain. The antibiotic susceptibility was tested quantitatively using the broth microdilution test. Based on initial and final MIC values, all tested isolates were susceptible ...

Isolated malignant melanoma metastasis to the pancreas

DEFF Research Database (Denmark)

Larsen, Anne K; Krag, Christen; Geertsen, Poul

2013-01-01

SUMMARY: Malignant melanomas rarely develop isolated pancreatic metastases. We describe a unique patient who is still alive 22 years following an isolated pancreatic melanoma metastasis, and we review the sparse literature in the field....

Molecular analysis of field strains of Mycoplasma capricolum subspecies capripneumoniae and Mycoplasma mycoides subspecies mycoides, small colony type isolated from goats in Tanzania

DEFF Research Database (Denmark)

Kusiluka, L.J.M.; Ojeniyi, B.; Friis, N.F.

2001-01-01

A molecular analysis of strains of Mycoplasma capricolum subsp, capripneumoniae (M. capripneumoniae) and Mycoplasma mycoides subsp. mycoides, small colony type (M. mycoides SQ isolated from goats was performed using the amplified fragment length polymorphism (AFLP) and pulsed-field gel...

Assessment of exit block following pulmonary vein isolation: far-field capture masquerading as entrance without exit block.

Science.gov (United States)

Vijayaraman, Pugazhendhi; Dandamudi, Gopi; Naperkowski, Angela; Oren, Jess; Storm, Randle; Ellenbogen, Kenneth A

2012-10-01

Complete electrical isolation of pulmonary veins (PVs) remains the cornerstone of ablation therapy for atrial fibrillation. Entrance block without exit block has been reported to occur in 40% of the patients. Far-field capture (FFC) can occur during pacing from the superior PVs to assess exit block, and this may appear as persistent conduction from PV to left atrium (LA). To facilitate accurate assessment of exit block. Twenty consecutive patients with symptomatic atrial fibrillation referred for ablation were included in the study. Once PV isolation (entrance block) was confirmed, pacing from all the bipoles on the Lasso catheter was used to assess exit block by using a pacing stimulus of 10 mA at 2 ms. Evidence for PV capture without conduction to LA was necessary to prove exit block. If conduction to LA was noticed, pacing output was decreased until there was PV capture without conduction to LA or no PV capture was noted to assess for far-field capture in both the upper PVs. All 20 patients underwent successful isolation (entrance block) of all 76 (4 left common PV) veins: mean age 58 ± 9 years; paroxysmal atrial fibrillation 40%; hypertension 70%, diabetes mellitus 30%, coronary artery disease 15%; left ventricular ejection fraction 55% ± 10%; LA size 42 ± 11 mm. Despite entrance block, exit block was absent in only 16% of the PVs, suggesting persistent PV to LA conduction. FFC of LA appendage was noted in 38% of the left superior PVs. FFC of the superior vena cava was noted in 30% of the right superior PVs. The mean pacing threshold for FFC was 7 ± 4 mA. Decreasing pacing output until only PV capture (loss of FFC) is noted was essential to confirm true exit block. FFC of LA appendage or superior vena cava can masquerade as persistent PV to LA conduction. A careful assessment for PV capture at decreasing pacing output is essential to exclude FFC. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Electric field control of magnetic states in isolated and dipole-coupled FeGa nanomagnets delineated on a PMN-PT substrate.

Science.gov (United States)

Ahmad, Hasnain; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo

2015-10-09

We report observation of a 'non-volatile' converse magneto-electric effect in elliptical FeGa nanomagnets delineated on a piezoelectric PMN-PT substrate. The nanomagnets are first magnetized with a magnetic field directed along their nominal major axes. Subsequent application of a strong electric field across the piezoelectric substrate generates strain in the substrate, which is partially transferred to the nanomagnets and rotates the magnetizations of some of them away from their initial orientations. The rotated magnetizations remain in their new orientations after the field is removed, resulting in 'non-volatility'. In isolated nanomagnets, the magnetization rotates by <90° upon application of the electric field, but in a dipole-coupled pair consisting of one 'hard' and one 'soft' nanomagnet, which are both initially magnetized in the same direction by the magnetic field, the soft nanomagnet's magnetization rotates by [Formula: see text] upon application of the electric field because of the dipole influence of the hard nanomagnet. This effect can be utilized for a nanomagnetic NOT logic gate.

Development and characterization of a magnetorheological elastomer based adaptive seismic isolator

International Nuclear Information System (INIS)

Li, Yancheng; Li, Jianchun; Samali, Bijan; Li, Weihua

2013-01-01

One of the main shortcomings in current base isolation design/practice is lack of adaptability. As a result, a base isolation system that is effective for one type earthquake may become ineffective or may have adverse effect for other earthquakes. The vulnerability of traditional base isolation systems can be exaggerated by two types of earthquakes, i.e. near-field earthquakes and far-field earthquakes. This paper addresses the challenge facing current base isolation design/practice by proposing a new type of seismic isolator for the base isolation system, namely an adaptive seismic isolator. The novel adaptive seismic isolator utilizes magnetorheological elastomer (MRE) for its field-sensitive material property. Traditional seismic isolator design with a unique laminated structure of steel and MRE layers has been adopted in the novel MRE seismic isolator. To evaluate and characterize the behavior of the MRE seismic isolator, experimental testing was conducted on a shake table facility under harmonic cycling loading. Experimental results show that the proposed adaptive seismic isolator can successfully alter the lateral stiffness and damping force in real time up to 37% and 45% respectively. Based on the successful development of the novel adaptive seismic isolator, a discussion is also extended to the impact and potential applications of such a device in structural control applications in civil engineering. (paper)

Isolation, Identification, and Characterization of a New Highly Pathogenic Field Isolate of Mycobacterium avium spp. avium

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Liangquan Zhu

2018-01-01

Full Text Available Avian tuberculosis is a chronic, contagious zoonotic disease affecting birds, mammals, and humans. The disease is most often caused by Mycobacterium avium spp. avium (MAA. Strain resources are important for research on avian tuberculosis and vaccine development. However, there has been little reported about the newly identified MAA strain in recent years in China. In this study, a new strain was isolated from a fowl with symptoms of avian tuberculosis by bacterial culture. The isolated strain was identified to be MAA by culture, staining, and biochemical and genetic analysis, except for different colony morphology. The isolated strain was Ziehl-Zeelsen staining positive, resistant to p-nitrobenzoic acid, and negative for niacin production, Tween-80 hydrolysis, heat stable catalase and nitrate production. The strain had the DnaJ gene, IS1245, and IS901, as well. Serum agglutination indicated that the MAA strain was of serotype 1. The MAA strain showed strong virulence via mortality in rabbits and chickens. The prepared tuberculin of the MAA strain had similar potency compared to the MAA reference strain and standard tuberculin via a tuberculin skin test. Our studies suggested that this MAA strain tends to be a novel subtype, which might enrich the strain resource of avian tuberculosis.

Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China)

OpenAIRE

Poltaraus, Andrey B.; Sokolova, Diyana S.; Grouzdev, Denis S.; Ivanov, Timophey M.; Malakho, Sophia G.; Korshunova, Alena V.; Rozanov, Aleksey S.; Tourova, Tatiyana P.; Nazina, Tamara N.

2016-01-01

The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus.

Enhanced Emission from Single Isolated Gold Quantum Dots Investigated Using Two-Photon-Excited Fluorescence Near-Field Scanning Optical Microscopy.

Science.gov (United States)

Abeyasinghe, Neranga; Kumar, Santosh; Sun, Kai; Mansfield, John F; Jin, Rongchao; Goodson, Theodore

2016-12-21

New approaches in molecular nanoscopy are greatly desired for interrogation of biological, organic, and inorganic objects with sizes below the diffraction limit. Our current work investigates emergent monolayer-protected gold quantum dots (nanoclusters, NCs) composed of 25 Au atoms by utilizing two-photon-excited fluorescence (TPEF) near-field scanning optical microscopy (NSOM) at single NC concentrations. Here, we demonstrate an approach to synthesize and isolate single NCs on solid glass substrates. Subsequent investigation of the NCs using TPEF NSOM reveals that, even when they are separated by distances of several tens of nanometers, we can excite and interrogate single NCs individually. Interestingly, we observe an enhanced two-photon absorption (TPA) cross section for single Au 25 NCs that can be attributed to few-atom local field effects and to local field-induced microscopic cascading, indicating their potential for use in ultrasensitive sensing, disease diagnostics, cancer cell therapy, and molecular computers. Finally, we report room-temperature aperture-based TPEF NSOM imaging of these NCs for the first time at 30 nm point resolution, which is a ∼5-fold improvement compared to the previous best result for the same technique. This report unveils the unique combination of an unusually large TPA cross section and the high photostability of Au NCs to (non-destructively) investigate stable isolated single NCs using TPEF NSOM. This is the first reported optical study of monolayer-protected single quantum clusters, opening some very promising opportunities in spectroscopy of nanosized objects, bioimaging, ultrasensitive sensing, molecular computers, and high-density data storage.

Phylogeny of Indonesian Nostoc (Cyanobac teria Isolated from Paddy Fields as Inferred from Partial Se quence of 16S rRNA Gene

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Dian Hendrayanti

2012-12-01

Full Text Available In order to collect Indonesian Nostoc, isolation of soil microflora from several paddy fields in West Java, Bali, andSouth Celebes was carried out. Fast-growing isolates of Nostoc were selected to describe and perform molecular identification using partial sequences of 16S rRNA. The results showed that partial sequences of 16S rRNA could not resolve the phylogeny of the isolates. However, it supported the morphological studies that recognize isolates as different species of Nostoc. Potential use of Nostoc as a nitrogen source for paddy growth was carried out using six strains as single inoculums. A total biomass of 2 g (fresh weight for each strain was inoculated, respectively, into the pot planted with three paddy plants. This experiment was conducted in the green house for 115 days. Statistical analyses (ANOVA; α = 0.05 showed that of six strains tested in this study, only strain GIA13a had influence on the augmentation of root length and the total number of filled grains.

Relatedness of Macrophomina phaseolina isolates from tallgrass prairie, maize, soybean and sorghum.

Science.gov (United States)

Saleh, A A; Ahmed, H U; Todd, T C; Travers, S E; Zeller, K A; Leslie, J F; Garrett, K A

2010-01-01

Agricultural and wild ecosystems may interact through shared pathogens such as Macrophomina phaseolina, a generalist clonal fungus with more than 284 plant hosts that is likely to become more important under climate change scenarios of increased heat and drought stress. To evaluate the degree of subdivision in populations of M. phaseolina in Kansas agriculture and wildlands, we compared 143 isolates from maize fields adjacent to tallgrass prairie, nearby sorghum fields, widely dispersed soybean fields and isolates from eight plant species in tallgrass prairie. Isolate growth phenotypes were evaluated on a medium containing chlorate. Genetic characteristics were analysed based on amplified fragment length polymorphisms and the sequence of the rDNA-internal transcribed spacer (ITS) region. The average genetic similarity was 58% among isolates in the tallgrass prairie, 71% in the maize fields, 75% in the sorghum fields and 80% in the dispersed soybean fields. The isolates were divided into four clusters: one containing most of the isolates from maize and soybean, two others containing isolates from wild plants and sorghum, and a fourth containing a single isolate recovered from Solidago canadensis in the tallgrass prairie. Most of the sorghum isolates had the dense phenotype on media containing chlorate, while those from other hosts had either feathery or restricted phenotypes. These results suggest that the tallgrass prairie supports a more diverse population of M. phaseolina per area than do any of the crop species. Subpopulations show incomplete specialization by host. These results also suggest that inoculum produced in agriculture may influence tallgrass prairie communities, and conversely that different pathogen subpopulations in tallgrass prairie can interact there to generate 'hybrids' with novel genetic profiles and pathogenic capabilities.

A deletion within glycoprotein L of Marek's disease virus (MDV) field isolates correlates with a decrease in bivalent MDV vaccine efficacy in contact-exposed chickens.

Science.gov (United States)

Tavlarides-Hontz, Phaedra; Kumar, Pankaj M; Amortegui, Juliana Rojas; Osterrieder, Nikolaus; Parcells, Mark S

2009-06-01

We examined the functional role of a naturally occurring deletion within the glycoprotein L (gL) gene of Marek's disease virus (MDV) field isolates. We previously showed that this mutation incrementally increased the virulence of an MDV in contact-exposed SPF leghorn chickens, when chickens shedding this virus were co-infected with herpesvirus of turkeys (HVT). In our present study, we examined this mutation using two stocks of the very virulent plus (vv+)MDV strain TK, one of which harbored this deletion (TK1a) while the other did not (TK2a). We report that TK1a replicating in vaccinated chickens overcame bivalent (HVT/SB1) vaccine protection in contact-exposed chickens. Treatment groups exposed to vaccinated chickens inoculated with a 1:1 mix of TK1a and TK2a showed decreased bivalent vaccine efficacy, and this decrease correlated with the prevalence of the gL deletion indicative of TK1a. These results were also found using quadruplicate treatment groups and bivalently vaccinated chickens obtained from a commercial hatchery. As this deletion was found in 25 out of 25 recent field isolates from Delaware, Maryland, North Carolina, Pennsylvania, and Virginia, we concluded that there is a strong selection for this mutation, which appears to have evolved in HVT or bivalently vaccinated chickens. This is the first report of a mutation in a vv+MDV field strain for which a putative biological phenotype has been discerned. Moreover, this mutation in gL has apparently been selected in MDV field isolates through Marek's disease vaccination.

Recombination between vaccine and field strains of canine parvovirus is revealed by isolation of virus in canine and feline cell cultures.

Science.gov (United States)

Mochizuki, Masami; Ohshima, Takahisa; Une, Yumi; Yachi, Akiko

2008-12-01

Canine parvovirus type 2 (CPV) is a pathogen that causes severe hemorrhagic gastroenteritis with a high fatality rate in pups worldwide. Since CPV emerged in the late 1970s, its origin has been explored with the conclusion that CPV originated from feline panleukopenia virus or a closely related virus. Both high mutation rate and recombination are assumed to be key factors in the evolution of parvoviruses. Here we provide evidence for natural recombination in CPV isolated from dogs in cell culture. Antigenic and genetic properties of isolates from 10 diseased pups were elucidated. Six pups had been vaccinated beforehand with live combined vaccine containing original antigenic type CPV (CPV-2). Six isolates recovered from 4 vaccinated pups in cell cultures were found to contain either CPV-2 or CPV-2-like viruses. The other isolates, including all those from non-vaccinated pups, were CPV-2b viruses. Antigenic typing of two CPV-2-like isolates, 03-029/M and 1887/f, with a monoclonal antibody panel suggested they were a mixture of CPV-2 and CPV-2a (03-029/M) and a recombinant of CPV-2 and CPV-2b (1887/f). Genetic analysis of the VP1 gene indicated that isolate 03-029/M was a mixture of CPV-2, CPV-2a and a recombinant of CPV-2 and CPV-2a viruses, while isolate 1887/f was composed of a recombinant of CPV-2 and CPV-2b viruses. This is the first demonstration of natural CPV recombination in the field and suggests that recombination in the evolution of CPV is a more frequent and important process than previously believed.

Investigation of the antigenic evolution of field isolates using the reverse genetics system of infectious bursal disease virus (IBDV).

Science.gov (United States)

Durairaj, Vijay; Sellers, Holly S; Linnemann, Erich G; Icard, Alan H; Mundt, Egbert

2011-10-01

The antigenic profiles of over 300 infectious bursal disease virus (IBDV) isolates were analyzed using a panel of monoclonal antibodies in a reverse genetics system. In addition, the sequences of a large portion of the neutralizing-antibody-inducing VP2 of IBDV were determined. Phylogenetic analysis of nucleotide and amino acid sequences in combination with the antigenic profiles obtained using the monoclonal antibody panel, revealed a lack of correlation between antigenicity and isolate's placement within the phylogenetic tree. In-depth analysis of amino acid exchanges revealed that changes within a certain region of the VP2 molecule resulted in differences in the antigenicity of the virus. This comprehensive analysis of VP2 sequences indicated a high selective pressure in the field that was likely due to vaccination programs, which increase the rate of evolution of the virus.

Landau-like theory for universality of critical exponents in quasistationary states of isolated mean-field systems.

Science.gov (United States)

Ogawa, Shun; Yamaguchi, Yoshiyuki Y

2015-06-01

An external force dynamically drives an isolated mean-field Hamiltonian system to a long-lasting quasistationary state, whose lifetime increases with population of the system. For second order phase transitions in quasistationary states, two nonclassical critical exponents have been reported individually by using a linear and a nonlinear response theories in a toy model. We provide a simple way to compute the critical exponents all at once, which is an analog of the Landau theory. The present theory extends the universality class of the nonclassical exponents to spatially periodic one-dimensional systems and shows that the exponents satisfy a classical scaling relation inevitably by using a key scaling of momentum.

Molecular mechanisms of fluoroquinolone resistance in Pseudomonas aeruginosa isolates from cystic fibrosis patients

DEFF Research Database (Denmark)

Jalal, S; Ciofu, O; Høiby, Niels

2000-01-01

Twenty P. aeruginosa isolates were collected from six cystic fibrosis (CF) patients, aged 27 to 33, in 1994 (9 isolates) and 1997 (11 isolates) at the CF Center, Copenhagen, Denmark, and were typed by pulse-field gel electrophoresis (PFGE) or ribotyping. Five of the patients had isolates with the......Twenty P. aeruginosa isolates were collected from six cystic fibrosis (CF) patients, aged 27 to 33, in 1994 (9 isolates) and 1997 (11 isolates) at the CF Center, Copenhagen, Denmark, and were typed by pulse-field gel electrophoresis (PFGE) or ribotyping. Five of the patients had isolates...

Noise cancellation in magnetoencephalography and electroencephalography with isolated reference sensors

Science.gov (United States)

Kraus, Jr., Robert H.; Espy, Michelle A.; Matlachov, Andrei; Volegov, Petr

2010-06-01

An apparatus measures electromagnetic signals from a weak signal source. A plurality of primary sensors is placed in functional proximity to the weak signal source with an electromagnetic field isolation surface arranged adjacent the primary sensors and between the weak signal source and sources of ambient noise. A plurality of reference sensors is placed adjacent the electromagnetic field isolation surface and arranged between the electromagnetic isolation surface and sources of ambient noise.

Use of Plant Extracts as an Effective Manner to Control Clostridium perfringens Induced Necrotic Enteritis in Poultry

Science.gov (United States)

Dominguez, J. E.; Chacana, A. P.

2016-01-01

Necrotic enteritis (NE) is an important concern in poultry industry since it causes economic losses, increased mortality, reduction of bird welfare, and contamination of chicken products for human consumption. For decades, the use of in-feed antimicrobial growth promoters (AGPs) has been the main strategy to control intestinal pathogens including Clostridium perfringens (CP), the causative agent of NE. However, the use of AGPs in animal diet has been linked to the emergence and transmission of antimicrobial resistance through food-borne microorganisms, which has led to the ban of AGPs in many countries. This scenario has challenged the poultry industry to search for safer alternative products in order to prevent NE. In this context, the utilization of natural plant extracts with antimicrobial properties appears as a promising and feasible tool to control NE in chicken. In this paper, we review the scientific studies analyzing the potential of plant extracts as alternative feed additives to reduce NE in poultry, with focus on two types of plant products that arise as promising candidates: tannins and essential oils. Some of these products showed antimicrobial activity against CP and coccidia in vitro and in vivo and are able to increase productive performance, emulating the bioactive properties of AGPs. PMID:27747227

Mycoplasma contamination of Chlamydia pneumoniae isolates

DEFF Research Database (Denmark)

Huniche, BS; Jensen, Lise Torp; Birkelund, Svend

1998-01-01

media, immunoblotting, polymerase chain reaction and pulsed field gel electrophoresis. Two of the 6 ATCC isolates [ATCC VR1355 (TWAR strain 2043) and ATCC VR1356 (TWAR strain 2023)] were infected with Mycoplasma hominis and 1 isolate [ATCC VR2282 (TWAR strain TW183)] was contaminated with both...... Mycoplasma hominis and Mycoplasma orale, whereas 3 of the ATCC isolates [ATCC VR1310, ATCC VR1360 (TWAR strain CM-1) and ATCC 53592 (TWAR strain AR39)] were not contaminated. The Finnish C. pneumoniae isolates Kajaani 6 and Parola were found to be contaminated with M. hominis and M. orale, respectively...

The HIV-1 V3 domain on field isolates: participation in generation of escape virus in vivo and accessibility to neutralizing antibodies

DEFF Research Database (Denmark)

Arendrup, M; Akerblom, L; Heegaard, P M

1995-01-01

The V3 domain is highly variable and induces HIV neutralizing antibodies (NA). Here we addressed the issues of 1) the participation of mutations in V3 in generation of neutralization resistant escape virus in vivo and 2) the applicability of synthetic V3 peptides corresponding to field isolates...... to induce neutralizing immune sera. Seven peptides corresponding to the V3 region of primary and escape virus from 3 HIV-1 infected patients were synthesized and used for antibody (Abs) studies and immunizations. The anti-V3 Abs titre in patient serum was generally low against peptides corresponding...... to autologous virus isolated later than the serum sample in contrast to the titre against peptides corresponding to virus isolated earlier than the serum sample. Furthermore, neutralizing anti-V3 monoclonal antibodies (MAbs) raised against V3 peptides from laboratory strains of HIV-1 showed distinct binding...

[Characterization of the genetic variability of field strains of Brucella canis isolated in Antioquia].

Science.gov (United States)

Vidal Arboleda, Juana L; Ortiz Roman, Luisa F; Olivera Angel, Martha

2017-12-22

Brucella canis is a facultative intracellular pathogen responsible for canine brucellosis, a zoonotic disease that affects canines, causing abortions and reproductive failure; and the production of non-specific symptoms in humans. In 2005 the presence of B. canis in Antioquia was demonstrated and the strains were identified as type 2. The sequencing of the genome of a field strain denoted Brucella canis str. Oliveri, showed species-specific indel events, which led us to investigate the genomic characteristics of the B. canis strain isolated and to establish the phylogenetic relationships and the divergence time of B. canis str. Oliveri. Conventional PCR sequencing was performed in 30 field strains identifying 5 indel events recognized in B. canis str. Oliveri. ADN from Brucella suis, Brucella melitensis and vaccine strains from Brucella abortus were used as control, and it was determined that all of the studied field strains shared 4 out of the 5 indels of the sequenced Oliveri strain, indicating the presence of more than one strain circulating in the region. Phylogenetic analysis was performed with 24 strains of Brucella using concatenated sequences of genetic markers for species differentiation. The molecular clock hypothesis and Tajima's relative rate test were tested, showing that the Oliveri strain, similarly to other canis species, diverged from B. suis. The molecular clock hypothesis between Brucella species was rejected and an evolution rate and a similar genetic distance between the B. canis were demonstrated. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Challenges in hardening technologies using shallow-trench isolation

International Nuclear Information System (INIS)

Shaneyfelt, M.R.; Dodd, P.E.; Draper, B.L.; Flores, R.S.

1998-02-01

Challenges related to radiation hardening CMOS technologies with shallow-trench isolation are explored. Results show that trench hardening can be more difficult than simply replacing the trench isolation oxide with a hardened field oxide

Molecular and in vitro Characterization of Field Isolates of Bovine Herpesvirus-1

Institute of Scientific and Technical Information of China (English)

Julian Ruiz-Saenz; Jairo Jaime; Gloria Ramirez; Victor Vera

2012-01-01

Bovine Herpesvirus-1 (BoHV-1) is distributed worldwide and is a major pathogen in cattle,being the causal agent of a variety of clinical syndromes.The aim of this study was to isolate and to characterize (molecular and biological characterization) BoHV- 1 from 29 immunosuppressed animals.It was possible to obtain 18 isolates,each from a different animal,such as from the respiratory and reproductive tracts.In some cases the cytopathic effect was visible 12 hours post-inoculation,and became characteristic after 36-48 hours.Biological characteristics were evaluated and compared with Iowa and Colorado-1 reference strains,and differences were found in plaque size,virus titer measured by TCID50 and PFU/mL,and one step virus curves.These results showed that some isolates had a highly virulent-like behavior in vitro,compared to the reference strains,with shorter eclipse periods,faster release of virus into the supematants,and higher burst size and viral titer.There were no differences in glycoprotein expression of BoHV-1 isolates,measured by Western blot on monolayers.Moreover,using restriction endonucleases analysis,most of the viruses were confirmed as BoHV-1.1 and just one of them was confirmed as BoHV-1.2a subtype.These findings suggest that some wild-type BoHV-1 isolates could be useful as seeds to develop new monovalent vaccines.

Comparison of sequences of hypervariable region (HVR subunit S-1 gene of field isolate I-37 infectious bronchitis virus with Connecticut serotype

Directory of Open Access Journals (Sweden)

N.L.P Indi Dharmayanti

2003-06-01

Full Text Available Infectious Bronchitis is a contagious and acute respiratory disease in chickens caused by infectious bronchitis virus (IBV.Antigenic differences in IBV are associated with changes in the sequence of the spike glycoprotein (S. The subunit S1 which demonstrates more sequence variability than S-2 have been identified as hypervariable region (HVR-1 and 2. There were several IB virus field isolates included I-37 have been identified in Indonesia by serum neutralization method. However, gene sequence variation in HVR subunit S-1 had not yet been identified. Isolate I-37 was close to the serotype Connecticut 46 (Conn 46. The aim of this study is to identify sequence variation of HVR subunit S-1 gene of isolate I-37 produced by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR and sequencing. Several procedures were carried out in the study including virus titration, propagation and was concentrated from the allantoic fluid infected with IBV. Then, RNA was extracted for RTPCR. urther the product was sequnced and its homology with IBV references from GenBank was compared by GenMac version 8.0. Result showed that isolate I-37 produced 515 bp of amplification product. Isolate I-37 and Conn 46 are same serotype, yet their HVR subunit S-1 nucleotides and amino acids (protein differ by 6.9% and 15.6% respectively. It might be concluded that isolate I-37 was variant of Conn 46.

Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China).

Science.gov (United States)

Poltaraus, Andrey B; Sokolova, Diyana S; Grouzdev, Denis S; Ivanov, Timophey M; Malakho, Sophia G; Korshunova, Alena V; Rozanov, Aleksey S; Tourova, Tatiyana P; Nazina, Tamara N

2016-06-09

The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus. Copyright © 2016 Poltaraus et al.

Isolating the impact of sediment toxicity in urban streams

International Nuclear Information System (INIS)

Marshall, Stephen; Pettigrove, Vincent; Carew, Melissa; Hoffmann, Ary

2010-01-01

Several factors can contribute to the ecological degradation of stream catchments following urbanization, but it is often difficult to separate their relative importance. We isolated the impact of polluted sediment on the condition of an urban stream in Melbourne, Australia, using two complementary approaches. Using a rapid bioassessment approach, indices of stream condition were calculated based on macroinvertebrate field surveys. Urban stream reaches supported impoverished macroinvertebrate communities, and contained potentially toxic concentrations of heavy metals and hydrocarbons. Using a field microcosm approach, a bioassay was carried out to assess sediment pollution effects on native macroinvertebrates. Sediment from urban sites substantially altered the microcosm macroinvertebrate community, most likely due to elevated heavy metal and hydrocarbon concentrations. Macroinvertebrate surveys combined with a bioassay approach based on field microcosms can help isolate the effect of stream pollutants in degraded ecosystems. - Field microcosms isolate the ecological impact of polluted sediment in an urban stream.

Quantification of gut lesions in a subclinical necrotic enteritis model

DEFF Research Database (Denmark)

Gholamiandehkordi, Ahmad R.; Timbermont, Leen; Lanckriet, Anouk

2007-01-01

Currently Clostridium perfringens-induced necrotic enteritis is a major problem in broiler flocks. In the present study, broilers were inoculated with a combination of Eimeria maxima or overdose coccidial vaccine (one inoculation) with C. perfringens (repeated inoculations). Single C. perfringens...... in combination with multiple oral C. perfringens inoculations is a suitable model for necrotic enteritis without inducing mortality of the animals. C. perfringens and Eimeria act synergistically in inducing grossly visible gut damage....

Toward Isolation of Salient Features in Stable Boundary Layer Wind Fields that Influence Loads on Wind Turbines

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Jinkyoo Park

2015-04-01

Full Text Available Neutral boundary layer (NBL flow fields, commonly used in turbine load studies and design, are generated using spectral procedures in stochastic simulation. For large utility-scale turbines, stable boundary layer (SBL flow fields are of great interest because they are often accompanied by enhanced wind shear, wind veer, and even low-level jets (LLJs. The generation of SBL flow fields, in contrast to simpler stochastic simulation for NBL, requires computational fluid dynamics (CFD procedures to capture the physics and noted characteristics—such as shear and veer—that are distinct from those seen in NBL flows. At present, large-eddy simulation (LES is the most efficient CFD procedure for SBL flow field generation and related wind turbine loads studies. Design standards, such as from the International Electrotechnical Commission (IEC, provide guidance albeit with simplifying assumptions (one such deals with assuming constant variance of turbulence over the rotor and recommend standard target turbulence power spectra and coherence functions to allow NBL flow field simulation. In contrast, a systematic SBL flow field simulation procedure has not been offered for design or for site assessment. It is instructive to compare LES-generated SBL flow fields with stochastic NBL flow fields and associated loads which we evaluate for a 5-MW turbine; in doing so, we seek to isolate distinguishing characteristics of wind shear, wind veer, and turbulence variation over the rotor plane in the alternative flow fields and in the turbine loads. Because of known differences in NBL-stochastic and SBL-LES wind fields but an industry preference for simpler stochastic simulation in design practice, this study investigates if one can reproduce stable atmospheric conditions using stochastic approaches with appropriate corrections for shear, veer, turbulence, etc. We find that such simple tuning cannot consistently match turbine target SBL load statistics, even though

Screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer.

Science.gov (United States)

Singh, Surendra; Datta, Pallavi

2006-01-01

Periodic applications of heavy dosages of herbicides in modern rice-agriculture are a necessary evil for obtaining high crop productivity. Such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. It is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice-field herbicides that can be further improved by mutational techniques to make biofertilizer technology a viable one. Therefore, efforts have been made to screen five dominant diazotrophic cyanobacterial forms e.g. filamentous heterocystous Nostoc punctiforme , Nostoc calcicola , Anabaena variabilis and unicellular Gloeocapsa sp. and Aphanocapsa sp. along with standard laboratory strain Nostoc muscorum ISU against increasing concentrations (0-100 mg l(-1) of four commercial grade common rice-field herbicides i.e. Arozin, Butachlor, Alachlor and 2,4-D under diazotrophic growth conditions. The lethal and IGC(50) concentrations for all four herbicides tested were found highest for A. variabilis as compared to other test cyanobacteria. The lowest reduction in chlorophyll a content, photosynthetic oxygen evolution, and N(2)-fixation was found in A. variabilis as compared to other rice field isolates and standard laboratory strain N. muscorum ISU. On the basis of prolong survival potential and lowest reductions in vital metabolic activities tested at IGC(50) concentration of four herbicides, it is concluded that A. variabilis is the most potent and promising cyanobacterial isolate as compared with other forms. This could be further improved by mutational techniques for exploitation as most potential and viable biofertilizer strain.

Genesis of magnetic fields in isolated white dwarfs

Science.gov (United States)

Briggs, Gordon P.; Ferrario, Lilia; Tout, Christopher A.; Wickramasinghe, Dayal T.

2018-05-01

A dynamo mechanism driven by differential rotation when stars merge has been proposed to explain the presence of strong fields in certain classes of magnetic stars. In the case of the high field magnetic white dwarfs (HFMWDs), the site of the differential rotation has been variously thought to be the common envelope, the hot outer regions of a merged degenerate core or an accretion disc formed by a tidally disrupted companion that is subsequently accreted by a degenerate core. We have shown previously that the observed incidence of magnetism and the mass distribution in HFMWDs are consistent with the hypothesis that they are the result of merging binaries during common envelope evolution. Here we calculate the magnetic field strengths generated by common envelope interactions for synthetic populations using a simple prescription for the generation of fields and find that the observed magnetic field distribution is also consistent with the stellar merging hypothesis. We use the Kolmogorov-Smirnov test to study the correlation between the calculated and the observed field strengths and find that it is consistent for low envelope ejection efficiency. We also suggest that field generation by the plunging of a giant gaseous planet on to a white dwarf may explain why magnetism among cool white dwarfs (including DZ white dwarfs) is higher than among hot white dwarfs. In this picture a super-Jupiter residing in the outer regions of the white dwarf's planetary system is perturbed into a highly eccentric orbit by a close stellar encounter and is later accreted by the white dwarf.

Determination of minimum inhibitory and minimum bactericidal concentrations of tiamulin against field isolates of Actinobacillus pleuropneumoniae.

Science.gov (United States)

Pridmore, Andrew; Burch, David; Lees, Peter

2011-08-05

Tiamulin activity was measured against 19 UK field isolates of Actinobacillus pleuropneumoniae collected between 2003 and 2009 and the type strain ATCC 27090 as a control, with the intention of comparing broth with serum as growth media. Broth microdilution MIC/MBC tests were performed in accordance with the Clinical and Laboratory Standards Institute (CLSI) guideline M31-A3, in 'Veterinary Fastidious Medium' (VFM) (supplemented Mueller-Hinton broth at pH 7.3) and in 100% swine serum. For improved precision, a modified, overlapping doubling-dilution series was used (tiamulin concentration range 0.3-72 μg/ml). The MBC was reported as the lowest concentration producing a 99.9% reduction in bacterial density in the sub-cultured well contents, relative to the starting inoculum. The mean MBC/MIC ratio for tiamulin against A. pleuropneumoniae in VFM was low (1.74:1), even though tiamulin is classed as a bacteriostatic drug. Only three of the 19 isolates and the reference strain grew in 100% serum and their MICs were higher than those determined in VFM. It is postulated that this difference was due to differences in pH of the matrices or binding of tiamulin to serum proteins or a combination of both factors. Copyright © 2011 Elsevier B.V. All rights reserved.

Application of Pulsed-Field Gel Electrophoresis and Binary Typing as Tools in Veterinary Clinical Microbiology and Molecular Epidemiologic Analysis of Bovine and Human Staphylococcus aureus Isolates

Science.gov (United States)

Zadoks, Ruth; van Leeuwen, Willem; Barkema, Herman; Sampimon, Otlis; Verbrugh, Henri; Schukken, Ynte Hein; van Belkum, Alex

2000-01-01

Thirty-eight bovine mammary Staphylococcus aureus isolates from diverse clinical, temporal, and geographical origins were genotyped by pulsed-field gel electrophoresis (PFGE) after SmaI digestion of prokaryotic DNA and by means of binary typing using 15 strain-specific DNA probes. Seven pulsed-field types and four subtypes were identified, as were 16 binary types. Concordant delineation of genetic relatedness was documented by both techniques, yet based on practical and epidemiological considerations, binary typing was the preferable method. Genotypes of bovine isolates were compared to 55 previously characterized human S. aureus isolates through cluster analysis of binary types. Genetic clusters containing strains of both human and bovine origin were found, but bacterial genotypes were predominantly associated with a single host species. Binary typing proved an excellent tool for comparison of S. aureus strains, including methicillin-resistant S. aureus, derived from different host species and from different databases. For 28 bovine S. aureus isolates, detailed clinical observations in vivo were compared to strain typing results in vitro. Associations were found between distinct genotypes and severity of disease, suggesting strain-specific bacterial virulence. Circumstantial evidence furthermore supports strain-specific routes of bacterial dissemination. We conclude that PFGE and binary typing can be successfully applied for genetic analysis of S. aureus isolates from bovine mammary secretions. Binary typing in particular is a robust and simple method and promises to become a powerful tool for strain characterization, for resolution of clonal relationships of bacteria within and between host species, and for identification of sources and transmission routes of bovine S. aureus. PMID:10790124

High-Voltage Isolation Transformer

Science.gov (United States)

Clatterbuck, C. H.; Ruitberg, A. P.

1985-01-01

Arcing and field-included surface erosion reduced by electrostatic shields around windings and ferromagnetic core of 80-kilovolt isolation transformer. Fabricated from high-resistivity polyurethane-based material brushed on critical surfaces, shields maintained at approximately half potential difference of windings.

Characterization of humoral responses to soluble trimeric HIV gp140 from a clade A Ugandan field isolate.

Science.gov (United States)

Visciano, Maria Luisa; Tagliamonte, Maria; Stewart-Jones, Guillaume; Heyndrickx, Leo; Vanham, Guido; Jansson, Marianne; Fomsgaard, Anders; Grevstad, Berit; Ramaswamy, Meghna; Buonaguro, Franco M; Tornesello, Maria Lina; Biswas, Priscilla; Scarlatti, Gabriella; Buonaguro, Luigi

2013-07-08

Trimeric soluble forms of HIV gp140 envelope glycoproteins represent one of the closest molecular structures compared to native spikes present on intact virus particles. Trimeric soluble gp140 have been generated by several groups and such molecules have been shown to induce antibodies with neutralizing activity against homologous and heterologous viruses. In the present study, we generated a recombinant trimeric soluble gp140, derived from a previously identified Ugandan A-clade HIV field isolate (gp14094UG018). Antibodies elicited in immunized rabbits show a broad binding pattern to HIV envelopes of different clades. An epitope mapping analysis reveals that, on average, the binding is mostly focused on the C1, C2, V3, V5 and C5 regions. Immune sera show neutralization activity to Tier 1 isolates of different clades, demonstrating cross clade neutralizing activity which needs to be further broadened by possible structural modifications of the clade A gp14094UG018. Our results provide a rationale for the design and evaluation of immunogens and the clade A gp14094UG018 shows promising characteristics for potential involvement in an effective HIV vaccine with broad activity.

Comparative Genomics of Field Isolates of Mycobacterium bovis and M. caprae Provides Evidence for Possible Correlates with Bacterial Viability and Virulence.

Directory of Open Access Journals (Sweden)

José de la Fuente

2015-11-01

Full Text Available Mycobacteria of the Mycobacterium tuberculosis complex (MTBC greatly affect humans and animals worldwide. The life cycle of mycobacteria is complex and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Recently, comparative genomics analyses have provided new insights into the evolution and adaptation of the MTBC to survive inside the host. However, most of this information has been obtained using M. tuberculosis but not other members of the MTBC such as M. bovis and M. caprae. In this study, the genome of three M. bovis (MB1, MB3, MB4 and one M. caprae (MB2 field isolates with different lesion score, prevalence and host distribution phenotypes were sequenced. Genome sequence information was used for whole-genome and protein-targeted comparative genomics analysis with the aim of finding correlates with phenotypic variation with potential implications for tuberculosis (TB disease risk assessment and control. At the whole-genome level the results of the first comparative genomics study of field isolates of M. bovis including M. caprae showed that as previously reported for M. tuberculosis, sequential chromosomal nucleotide substitutions were the main driver of the M. bovis genome evolution. The phylogenetic analysis provided a strong support for the M. bovis/M. caprae clade, but supported M. caprae as a separate species. The comparison of the MB1 and MB4 isolates revealed differences in genome sequence, including gene families that are important for bacterial infection and transmission, thus highlighting differences with functional implications between isolates otherwise classified with the same spoligotype. Strategic protein-targeted analysis using the ESX or type VII secretion system, proteins linking stress response with lipid metabolism, host T cell epitopes of mycobacteria, antigens and peptidoglycan assembly protein identified new genetic markers and candidate vaccine antigens that warrant

Comparative Genomics of Field Isolates of Mycobacterium bovis and M. caprae Provides Evidence for Possible Correlates with Bacterial Viability and Virulence.

Science.gov (United States)

de la Fuente, José; Díez-Delgado, Iratxe; Contreras, Marinela; Vicente, Joaquín; Cabezas-Cruz, Alejandro; Tobes, Raquel; Manrique, Marina; López, Vladimir; Romero, Beatriz; Bezos, Javier; Dominguez, Lucas; Sevilla, Iker A; Garrido, Joseba M; Juste, Ramón; Madico, Guillermo; Jones-López, Edward; Gortazar, Christian

2015-11-01

Mycobacteria of the Mycobacterium tuberculosis complex (MTBC) greatly affect humans and animals worldwide. The life cycle of mycobacteria is complex and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Recently, comparative genomics analyses have provided new insights into the evolution and adaptation of the MTBC to survive inside the host. However, most of this information has been obtained using M. tuberculosis but not other members of the MTBC such as M. bovis and M. caprae. In this study, the genome of three M. bovis (MB1, MB3, MB4) and one M. caprae (MB2) field isolates with different lesion score, prevalence and host distribution phenotypes were sequenced. Genome sequence information was used for whole-genome and protein-targeted comparative genomics analysis with the aim of finding correlates with phenotypic variation with potential implications for tuberculosis (TB) disease risk assessment and control. At the whole-genome level the results of the first comparative genomics study of field isolates of M. bovis including M. caprae showed that as previously reported for M. tuberculosis, sequential chromosomal nucleotide substitutions were the main driver of the M. bovis genome evolution. The phylogenetic analysis provided a strong support for the M. bovis/M. caprae clade, but supported M. caprae as a separate species. The comparison of the MB1 and MB4 isolates revealed differences in genome sequence, including gene families that are important for bacterial infection and transmission, thus highlighting differences with functional implications between isolates otherwise classified with the same spoligotype. Strategic protein-targeted analysis using the ESX or type VII secretion system, proteins linking stress response with lipid metabolism, host T cell epitopes of mycobacteria, antigens and peptidoglycan assembly protein identified new genetic markers and candidate vaccine antigens that warrant further study to

Tiamulin resistance in porcine Brachyspira pilosicoli isolates.

Science.gov (United States)

Pringle, M; Landén, A; Franklin, A

2006-02-01

There are few studies on antimicrobial susceptibility of Brachyspira pilosicoli, therefore this study was performed to investigate the situation among isolates from pigs. The tiamulin and tylosin susceptibility was determined by broth dilution for 93 and 86 porcine B. pilosicoli isolates, respectively. The isolates came from clinical samples taken in Swedish pig herds during the years 2002 and 2003. The tylosin minimal inhibitory concentration (MIC) was >16 microg/ml for 50% (n=43) of the isolates tested. A tiamulin MIC >2 microg/ml was obtained for 14% (n=13) of the isolates and these were also tested against doxycycline, salinomycin, valnemulin, lincomycin and aivlosin. For these isolates the susceptibility to salinomycin and doxycycline was high but the MICs for aivlosin varied. The relationship between the 13 tiamulin resistant isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Among the 13 isolates 10 different PFGE patterns were identified.

Strategic control of acute diarrhea of newborn calves

Directory of Open Access Journals (Sweden)

Siti Chotiah

2012-10-01

Full Text Available Economic performance of beef cattle operations can be severely hampered by acute calfhood diarrhea. Accordingly, a study was conducted at Bbalitvet to identify the causal agents, reduce clinical incidence, and increase body weight gain of newborn calves. One potential control is application of suitable vaccines to pregnant cows. The study was begun by identifying cases of diarrhea followed by isolation and identification of the causal agents in 12 beef cattle farms in West Java. A field trial was then designed for controlling calf diarrhea in such farms. Inactive vaccines Ecoli-Closvak polivalen were administered to pregnant cows to increase specific resistance of the newborn calves. At 2 months prepartum, 12 pregnant cows were assigned either to a vaccination or a placebo group, with a booster vaccination 3 weeks prior to parturition. Strict hygenic management was provided to both groups, and all calves were provided adequately with colostrum. Subjects were observed for 5 months, starting from the time of initial vaccination until the calves were 3 months of age. In the initial farm surveys, entero-pathogenic bacteria such as Escherichia coli serotype K99 and Clostridium perfringens type A and C were isolated and identified in fecal samples from 4 beef cattle farms in 3 districts (Garut, Tasikmalaya, Ciamis and 2 beef cattle farms in 2 districts (Tasikmalaya and Ciamis of West Java. In the vaccination trial, good immune responses to E. coli and C. perfringens alpha toxin measured by ELISA were observed. Application of effective control of calf diarrhea including vaccination and good livestock management showed good results. No death or signs of diarrhea were found in the new born calves up to 3 months of age. The rate of body weight gain was significantly higher in calves of vaccinated dams than in calves of non-vaccinated dams.

Novel protocol for persister cells isolation.

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Silvia J Cañas-Duarte

Full Text Available Bacterial persistence, where a fraction of a population presents a transient resistance to bactericidal substances, has great medical importance due to its relation with the appearance of antibiotic resistances and untreatable bacterial chronic infections. The mechanisms behind this phenomenon remain largely unknown in spite of recent advances, in great part because of the difficulty in isolating the very small fraction of the population that is in this state at any given time. Current protocols for persister isolation have resulted in possible biases because of the induction of this state by the protocol itself. Here we present a novel protocol that allows rapid isolation of persister cells both from exponential and stationary phase. Moreover, it is capable of differentiating between type I and type II persister cells, which should allow the field to move beyond its current state of studying only one type. While this protocol prompts a revision of many of the current results, it should greatly facilitate further advances in the field.

Microbiological quality and potential public health risks of export meat from springbok (Antidorcas marsupialis) in Namibia.

Science.gov (United States)

Magwedere, K; Shilangale, R; Mbulu, R S; Hemberger, Y; Hoffman, L C; Dziva, F

2013-01-01

To assess the microbiological quality and safety of export game meat; i) a total of 80 pooled meat samples for aerobic plate count (APC) and Enterobacteriaceae ii) water used in harvesting and processing for microbiological quality and iii) meat and rectal contents for Salmonella spp. and Shiga toxin Escherichia coli (STEC) were evaluated in 2009 and 2010. No differences (p>0.05) in the APCs were observed between the years, but the mean Enterobacteriaceae count for 2009 was 1.33 ± 0.69 log(10)cfu/cm(2) compared to 2.93 ± 1.50 log(10)cfu/cm(2) for 2010. Insignificant Heterotrophic Plate Count (HPC) levels were detected in 9/23 field water samples, while fecal bacterial (coliforms, Clostridium perfringens and enterococci) were absent in all samples. No Salmonella spp. was isolated and all E. coli isolates from meat were negative for STEC virulence genes (stx1, stx2, eae and hlyA), suggesting a negligible role by springbok in the epidemiology of STEC and Salmonella. Copyright © 2012 Elsevier Ltd. All rights reserved.

Detection of a Bacteriophage Gene Encoding a Mu-like Portal Protein in Haemophilus parasuis Reference Strains and Field Isolates by Nested Polymerase Chain Reaction

Science.gov (United States)

A nested PCR assay was developed to determine the presence of a gene encoding a bacteriophage Mu-like portal protein, gp29, in 15 reference strains and 31 field isolates of Haemophilus parasuis. Specific primers, based on the gene’s sequence, were utilized. A majority of the virulent reference strai...

Evidence for high genetic diversity of NAD1 and COX1 mitochondrial haplotypes among triclabendazole resistant and susceptible populations and field isolates of Fasciola hepatica (liver fluke) in Australia.

Science.gov (United States)

Elliott, T; Muller, A; Brockwell, Y; Murphy, N; Grillo, V; Toet, H M; Anderson, G; Sangster, N; Spithill, T W

2014-02-24

In recent years, the global incidence of Fasciola hepatica (liver fluke) infections exhibiting resistance to triclabendazole (TCBZ) has increased, resulting in increased economic losses for livestock producers and threatening future control. The development of TCBZ resistance and the worldwide discovery of F. hepatica population diversity has emphasized the need to further understand the genetic structure of drug susceptible and resistant Fasciola populations within Australia. In this study, the genetic diversity of liver flukes was estimated by sequencing mitochondrial DNA (mtDNA) encoding the NAD1 (530 bp) and COX1 (420 bp) genes of 208 liver flukes (F. hepatica) collected from three populations: field isolates obtained from abattoirs from New South Wales (NSW) and Victoria (Vic); three TCBZ-resistant fluke populations from NSW and Victoria; and the well-established TCBZ-susceptible Sunny Corner laboratory isolate. Overall nucleotide diversity for all flukes analysed of 0.00516 and 0.00336 was estimated for the NAD1 and COX1 genes respectively. Eighteen distinct haplotypes were established for the NAD1 gene and six haplotypes for the COX1 gene, resulting in haplotype diversity levels of 0.832 and 0.482, respectively. One field isolate showed a similar low level of haplotype diversity as seen in the Sunny Corner laboratory isolate. Analysis of TCBZ-resistant infrapopulations from 3 individual cattle grazing one property revealed considerable sequence parasite diversity between cattle. Analysis of parasite TCBZ-resistant infrapopulations from sheep and cattle revealed haplotypes unique to each host, but no significant difference between parasite populations. Fst analysis of fluke populations revealed little differentiation between the resistant and field populations. This study has revealed a high level of diversity in field and drug resistant flukes in South-Eastern Australia. Copyright © 2013 Elsevier B.V. All rights reserved.

Isolation and purification of Gallid herpesvirus 2 strains currently distributed in Japan.

Science.gov (United States)

Machida, Yuka; Murata, Shiro; Matsuyama-Kato, Ayumi; Isezaki, Masayoshi; Taneno, Akira; Sakai, Eishi; Konnai, Satoru; Ohashi, Kazuhiko

2017-01-20

Gallid herpesvirus 2 (GaHV-2) causes malignant lymphomas in chickens (Marek's disease, MD). Although MD is controlled through vaccination efforts, field isolates of GaHV-2 have increased in virulence worldwide and even cause MD in vaccinated chickens. GaHV-2 strains are classified into four categories (mild, virulent, very virulent and very virulent +) based on the virulence exhibited in experimental infection in unvaccinated or MD-vaccinated susceptible chickens. Although MD cases are sporadically reported in Japan, the recent field strains of GaHV-2 in Japan have not been characterized. During isolation of recent field strains by using primary chicken kidney cell cultures, a method classically used for GaHV-2 isolation, vaccine strains were simultaneously isolated. Therefore, it is necessary to separate vaccine strains to characterize the virulence and pathogenicity of the GaHV-2 strains currently distributed in Japan. In this study, we prepared cell suspensions from the spleens of MD-symptomatic chickens, inoculated day-old-chicks and isolated GaHV-2 strains by primary chicken kidney cell cultures at 2-3 weeks post inoculation. The isolated strains were passaged several times on chicken embryo fibroblast cells, and PCR analysis revealed that the isolated strains were not contaminated with vaccine strains. Moreover, the contaminant vaccine strains were completely removed by the purification of plaques observed in chicken kidney cells. These procedures are necessary to isolate GaHV-2 field strains from vaccine strains in order to carry out future studies to characterize these strains and glean insights into GaHV-2 virulence and pathogenicity.

Competition Between Fusarium pseudograminearum and Cochliobolus sativus Observed in Field and Greenhouse Studies.

Science.gov (United States)

Troth, Erin E Gunnink; Johnston, Jeffrey A; Dyer, Alan T

2018-02-01

Among root pathogens, one of the most documented antagonisms is the suppression of Cochliobolus sativus by Fusarium (roseum) species. Unfortunately, previous studies involved single isolates of each pathogen and thus, provided no indication of the spectrum of responses that occur across the respective species. To investigate the variability in interactions between Cochliobolus sativus and Fusarium pseudograminearum, field and greenhouse trials were conducted that included monitoring of spring wheat plant health and monitoring of pathogen populations via quantitative real-time polymerase chain reaction. The interactions between two isolates of C. sativus and four isolates of F. pseudograminearum were explored in three geographically distinct wheat fields. To complement field trials and to limit potentially confounding environmental variables that are often associated with field studies, greenhouse trials were performed that investigated the interactions among and between three isolates of C. sativus and four isolates of F. pseudograminearum. Across field locations, C. sativus isolate Cs2344 consistently and significantly reduced Fusarium populations by an average of 20.1%. Similarly, F. pseudograminearum isolate Fp2228 consistently and significantly reduced C. sativus field populations by an average of 30.9%. No interaction was detected in the field between pathogen species with regards to disease or crop losses. Greenhouse results confirmed a powerful (>99%), broadly effective suppression of Fusarium populations by isolate Cs2344. Among greenhouse trials, additional isolate-isolate interactions were observed affecting Fusarium populations. Due to lower C. sativus population sizes in greenhouse trials, significant Fusarium suppression of C. sativus was only detected in one isolate-isolate interaction. This study is the first to demonstrate suppression of Fusarium spp. by C. sativus in field and greenhouse settings. These findings also reveal a complex competitive

Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation.

Science.gov (United States)

Sakpirom, Jakkapan; Kantachote, Duangporn; Nunkaew, Tomorn; Khan, Eakalak

2017-04-01

This study was aimed at selecting purple non-sulfur bacteria (PNSB) isolated from various paddy fields, including Cd- and Zn-contaminated paddy fields, based on their biofertilizer properties. Among 235 PNSB isolates, strain TN110 was most effective in plant growth-promoting substance (PGPS) production, releasing 3.2 mg/L of [Formula: see text] , 4.11 mg/L of 5-aminolevulinic acid (ALA) and 3.62 mg/L of indole-3-acetic acid (IAA), and reducing methane emission up to 80%. This strain had nifH, vnfG and anfG, which are the Mo, V and Fe nitrogenase genes encoded for key enzymes in nitrogen fixation under different conditions. This strain provided 84% and 55% removal of Cd and Zn, respectively. Another isolate, TN414, not only produced PGPS (1.30 mg/L of [Formula: see text] , 0.94 mg/L of ALA and 0.65 mg/L of IAA), but was also efficient in removing both Cd and Zn at 72% and 74%, respectively. Based on 16S rDNA sequencing, strain TN110 was identified as Rhodopseudomonas palustris, while strain TN414 was Rubrivivax gelatinosus. A combination of TN110 and TN414 could potentially provide a biofertilizer, which is a greener alternative to commercial/chemical fertilizers and an agent for bioremediation of heavy metals and greenhouse gas mitigation in paddy fields. Copyright © 2016 Institut Pasteur. All rights reserved.

Entanglement dynamics between an isolated atom and a moving atom in the cavity

International Nuclear Information System (INIS)

Xiao-Juan, Deng; Mao-Fa, Fang; Guo-Dong, Kang

2009-01-01

The entanglement dynamics between an isolated atom and a moving atom interacting with a cavity field is investigated. The results show that there appears sudden death of entanglement between the isolated atom and the moving atom and that the time of entanglement sudden death (ESD) is independent of the initial state of the system. It is interesting that the isolated atom can also entangle with a cavity field, though they do not interact with each other originally, which stems from the fact that the entanglement between the isolated atom and the moving atom may turn into the entanglement between the isolated atom and the cavity. (general)

Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer

Directory of Open Access Journals (Sweden)

Praveen Shenoy K

2018-01-01

Full Text Available Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE, whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems.

In vitro susceptibilities of recent field isolates of Mycoplasma hyopneumoniae and Mycoplasma hyosynoviae to valnemulin (Econor), tiamulin and enrofloxacin and the in vitro development of resistance to certain antimicrobial agents in Mycoplasma hyopneumoniae.

Science.gov (United States)

Hannan, P C; Windsor, H M; Ripley, P H

1997-01-01

The in vitro activities of valnemulin (Econor) and two other antimicrobial agents were determined against recent field strains of Mycoplasma hyopneumoniae and Mycoplasma hyosynoviae using a broth microdilution method. Valnemulin showed exceptional activity against M hyopneumoniae (MIC90 0.0005 microgram ml-1) and M hyosynoviae (MIC range 0.0001 microgram ml-1 to 0.00025 microgram ml-1) field strains. Tiamulin was 100-fold less active (MIC90 0.05 microgram ml-1) and enrofloxacin 20-fold less active (MIC90 0.01 microgram ml-1) than valnemulin against M hyopneumoniae field isolates and 20-fold to 25-fold less active (MIC range 0.0025 microgram ml-1 to 0.005 microgram ml-1) and 400-fold to 500-fold less active (MIC range 0.05 microgram ml-1 to 0.1 microgram ml-1) respectively against M hyosynoviae field isolates. No significant resistance developed to valnemulin or tiamulin in the type strain of M hyopneumoniae (strain J) or in a recent field isolate (MEVT G23) exposed to 10 in vitro passages in broths containing these antibiotics. Only slight resistance to oxytetracycline was observed. High resistance to tylosin developed in both M hyopneumoniae strains within five to seven in vitro passages in tylosin-containing broth. Providing that similar results are obtained in vivo under field conditions, valnemulin may well prove to be effective in the treatment of enzootic pneumonia and acute polyarthritis in pigs.

Few-cycle isolated attosecond pulses

International Nuclear Information System (INIS)

Sansone, G.; Benedetti, E.; Calegari, F.; Stagira, S.; Vozzi, C.; Silvestri De, S.; Nisoli, M.

2006-01-01

Complete test of publication follows. In the last few years the field of attosecond science has shown impressive and rapid progress, mainly due to the introduction of novel experimental methods for the characterization of extreme ultraviolet (XUV) pulses and attosecond electron wave packets. This development has been also triggered by significant improvements in the control of the electric field of the driving infrared pulses. Particularly interesting for the applications is the generation of isolated attosecond XUV pulses using few-cycle driving pulses. In this case significant progresses have been achieved thanks to the stabilization of the carrier-envelope phase (CEP) of amplified light pulses. In this work we demonstrate that the polarization gating (PG) method with few-cycle phase-stabilized driving pulses allows one to generate few-cycle isolated attosecond pulses tunable on a very broad spectral region. The PG method is based on temporal modulation of the ellipticity of a light pulse, which confines the XUV emission in the temporal gate where the polarization is close to linear. The time-dependent polarization of phase-stabilized sub-6-fs pulses, generated by the hollow fiber technique, has been obtained using two birefringent plates. It is possible to create a linear polarization gate, whose position is imposed by the intensity profile of the pulse whilst the emission time is linked to the CEP of the electric field. The pulses have been analyzed by using a flat-field spectrometer. Continuous XUV spectra, corresponding to the production of isolated attosecond pulses, have been generated for particular CEP values. Upon changing the rotation of the first plate it was possible to tune the XUV emission in a broad spectra range. We have then achieved a complete temporal characterization of the generated isolated attosecond pulses using frequency-resolved optical gating for complete reconstruction of attosecond bursts (FROG CRAB). The measured parabolic phase

Masking of the contribution of V protein to sendai virus pathogenesis in an infection model with a highly virulent field isolate

International Nuclear Information System (INIS)

Sakaguchi, Takemasa; Kiyotani, Katsuhiro; Watanabe, Hitoshi; Huang Cheng; Fukuhara, Noriko; Fujii, Yutaka; Shimazu, Yukie; Sugahara, Fumihiro; Nagai, Yoshiyuki; Yoshida, Tetsuya

2003-01-01

Sendai virus V protein is not essential for virus replication in cultured cells but is essential for efficient virus replication and pathogenesis in mice, indicating that the V protein has a luxury function to facilitate virus propagation in mice. This was discovered in the Z strain, an egg-adapted avirulent laboratory strain. In the present study, we reexamined the function of Sendai virus V protein by generating a V-knockout Sendai virus derived from the Hamamatsu strain, a virulent field isolate, which is an appropriate model for studying the natural course of Sendai virus infection in mice. We unexpectedly found that the V-knockout virus propagated efficiently in mice and was as virulent as the wild-type virus. Switching of the functionally important V unique region demonstrated that this region of the Hamamatsu strain was also functional in a Z strain background. It thus appears that the V protein is nonsense in a field isolate of Sendai virus. However, the V protein was required for virus growth and pathogenesis of the Hamamatsu strain in mice when the virulence of the virus was attenuated by introducing mutations that had been found in an egg-adapted, avirulent virus. The V protein therefore seems to be potentially functional in the highly virulent Hamamatsu strain and to be prominent if virus replication is restricted

Quantitative Field Testing Rotylenchulus reniformis DNA from Metagenomic Samples Isolated Directly from Soil

Science.gov (United States)

Showmaker, Kurt; Lawrence, Gary W.; Lu, Shien; Balbalian, Clarissa; Klink, Vincent P.

2011-01-01

A quantitative PCR procedure targeting the β-tubulin gene determined the number of Rotylenchulus reniformis Linford & Oliveira 1940 in metagenomic DNA samples isolated from soil. Of note, this outcome was in the presence of other soil-dwelling plant parasitic nematodes including its sister genus Helicotylenchus Steiner, 1945. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from soil. PMID:22194958

Use of natural ingredients to control growth of Clostridium perfringens in naturally cured frankfurters and hams.

Science.gov (United States)

Jackson, Armitra L; Kulchaiyawat, Charlwit; Sullivan, Gary A; Sebranek, Joseph G; Dickson, James S

2011-03-01

A major concern for processed meats marketed as natural/organic is that they do not contain nitrite in concentrations known to be most effective for inhibiting foodborne pathogens. Supplemental treatments to increase the level and consistency of antimicrobial protection in these products may be important to provide consumers with the degree of safety that they have come to expect from conventionally cured meats. Therefore, the objective of this study was to identify and test ingredients that might improve processed meat product safety without altering their natural/organic status. Eight treatments of hams and frankfurters were prepared: (A) uncured control (typical ingredients except nitrite and nitrate); (B) conventionally cured control (erythorbate, nitrite, and a lactate-diacetate blend); (C) natural nitrate cure (including starter culture containing Staphylococcus carnosus); (D) natural nitrate cure (culture and natural antimicrobial A containing a vinegar, lemon, and cherry powder blend); (E) natural nitrate cure (culture and antimicrobial B containing a cultured sugar and vinegar blend); (F) natural nitrite cure without additional antimicrobials; (G) natural nitrite cure with natural antimicrobial A; and (H) natural nitrite cure with antimicrobial B. For the hams, treatments C, D, E, and H impacted growth of Clostridium perfringens to the same extent (P cured control (approximately 2 log less growth over time than uncured control). For frankfurters, treatments D, G, and H had an effect (approximately 1 log) on growth equivalent to that of the conventionally cured control (P cured meats have more potential for pathogen growth than conventionally cured products, but supplemental natural ingredients offer safety improvement.

Biodegradation of buprofezin by Rhodococcus sp. strain YL-1 isolated from rice field soil.

Science.gov (United States)

Li, Chao; Zhang, Ji; Wu, Zhi-Guo; Cao, Li; Yan, Xin; Li, Shun-Peng

2012-03-14

A buprofezin-degrading bacterium, YL-1, was isolated from rice field soil. YL-1 was identified as Rhodococcus sp. on the basis of the comparative analysis of 16S rDNA sequences. The strain could use buprofezin as the sole source of carbon and nitrogen for growth and was able to degrade 92.4% of 50 mg L(-1) buprofezin within 48 h in liquid culture. During the degradation of buprofezin, four possible metabolites, 2-tert-butylimino-3-isopropyl-1,3,5-thiadiazinan-4-one, N-tert-butyl-thioformimidic acid formylaminomethyl ester, 2-isothiocyanato-2-methyl-propane, and 2-isothiocyanato-propane, were identified using gas chromatography-mass spectrometry (GC-MS) analysis. The catechol 2,3-dioxygenase activity was strongly induced during the degradation of buprofezin. A novel microbial biodegradation pathway for buprofezin was proposed on the basis of these metabolites. The inoculation of soils treated with buprofezin with strain YL-1 resulted in a higher degradation rate than that observed in noninoculated soils, indicating that strain YL-1 has the potential to be used in the bioremediation of buprofezin-contaminated environments.

Diversity of pulsed-field gel electrophoresis pulsotypes, serovars, and antibiotic resistance among Salmonella isolates from wild amphibians and reptiles in the California Central Coast.

Science.gov (United States)

Gorski, Lisa; Jay-Russell, Michele T; Liang, Anita S; Walker, Samarpita; Bengson, Yingjia; Govoni, Jessica; Mandrell, Robert E

2013-06-01

A survey of cold-blooded vertebrates and associated surface waters in a produce-growing region on the Central California Coast was done between May and September 2011 to determine the diversity of Salmonella. Samples from 460 amphibians and reptiles and 119 water samples were collected and cultured for Salmonella. Animals sampled were frogs (n=331), lizards (n=59), newts (n=5), salamanders (n=6), snakes (n=39), and toads (n=20). Salmonella was isolated from 37 individual animals, including frogs, lizards, snakes, and toads. Snakes were the most likely to contain Salmonella, with 59% testing positive followed by 15.3% of lizards, 5% of toads, and 1.2% of frogs. Fifteen water samples (12.6%) were positive. Twenty-two different serovars were identified, and the majority of isolates were S. enterica subsp. IIIb, with subsp. I, II, and IIIa also found. The serovar isolated most frequently was S. enterica subsp. IIIb 16:z₁₀:e,n,x,z₁₅, from snakes and frogs in five different locations. S. enterica subsp. I serovar Typhimurium and the monophasic I 6,8:d:- were isolated from water, and subspecies I Duisburg and its variants were found in animals and water. Some samples contained more than one type of Salmonella. Analysis of pulsed-field gel electrophoresis pulsotypes indicated that some strains persisted in animals and water collected from the same location. Sixty-six isolates displayed antibiotic resistance, with 27 isolates resistant to more than one antibiotic, including a subspecies IIIb isolate from snake having resistance to five different antibiotics. Twenty-three isolates were resistant to more than one class of antibiotic, and six isolates were resistant to three classes. While these subspecies of IIIa and IIIb cause fewer instances of human illness, they may serve as reservoirs of antibiotic resistance, determinants in the environment, and be sources of contamination of leafy greens associated with product recalls.

Antigenic and genomic homogeneity of successive Mycoplasma hominis isolates

DEFF Research Database (Denmark)

Jensen, Lise Torp; Thorsen, P; Møller, B

1998-01-01

Sixty Mycoplasma hominis isolates were obtained from the cervices of pregnant women and from the ears or pharynges of their newborn babies. The isolates were examined by SDS-PAGE and pulsed-field gel electrophoresis. Antigenic and genomic profiles were obtained for 16 series with two or more...

The effect of commonly used anticoccidials and antibiotics in a subclinical necrotic enteritis model.

Science.gov (United States)

Lanckriet, A; Timbermont, L; De Gussem, M; Marien, M; Vancraeynest, D; Haesebrouck, F; Ducatelle, R; Van Immerseel, F

2010-02-01

Necrotic enteritis poses an important health risk to broilers. The ionophore anticoccidials lasalocid, salinomycin, maduramicin, narasin and a combination of narasin and nicarbazin were tested in feed for their prophylactic effect on the incidence of necrotic enteritis in a subclinical experimental infection model that uses coccidia as a predisposing factor. In addition, drinking water medication with the antibiotics amoxicillin, tylosin and lincomycin was evaluated as curative treatment in the same experimental model. The minimal inhibitory concentrations (MICs) of all antibiotics and anticoccidials were determined in vitro against 51 Clostridium perfringens strains isolated from broilers. The strains examined appeared uniformly susceptible to lasalocid, maduramicin, narasin, salinomycin, amoxicillin and tylosin, whereas an extended frequency distribution range of MICs for lincomycin was seen, indicating acquired resistance in 36 isolates in the higher range of MICs. Nicarbazin did not inhibit the in vitro growth of the C. perfringens strains even at a concentration of 128 microg/ml. Supplementation of the diet from day 1 onwards with lasalocid, salinomycin, narasin or maduramicin led to a reduction in birds with necrotic enteritis lesions as compared with the non-medicated infected control group. A combination product of narasin and nicarbazin had no significant protective effect. Treatment with amoxicillin, lincomycin and tylosin completely stopped the development of necrotic lesions.

Isolation and Characterization of Blue Green Algae from Egyptian ...

African Journals Online (AJOL)

meldemellawy

2014-02-20

Feb 20, 2014 ... aminotransferase (AMT) domains of the mycE and ndaF genes (Jungblut et al., 2006) allowing detection of microcystin and nodularin-producing cyanobacteria. MATERIALS AND METHODS. Isolation and cultivation of blue green algae. Blue green algae had been isolated from soil of Rice field in river.

The genotypic characterization of Cronobacter spp. isolated in China.

Directory of Open Access Journals (Sweden)

Jinghua Cui

Full Text Available Cronobacter spp. (Enterobacter sakazakii is an important pathogen contaminating powdered infant formula (PIF. To describe the genotypic diversity of Cronobacter isolated in China, we identified the isolates using fusA allele sequencing, and subtyped all of the isolates using pulsed-field gel electrophoresis (PFGE, multi-locus sequence typing (MLST, and multiple-locus variable-number tandem-repeat analysis (MLVA. A total of 105 isolates were identified, which included C. sakazakii (58 isolates, C. malonaticus (30 isolates, C. dublinensis (11 isolates, C. turicensis (5 isolates, and C. muytjensii (1 isolate. These isolates were showed to have 85 PFGE-patterns, 71 sequence types (STs, and 55 MLVA-patterns. Comparisons among the three molecular subtyping methods revealed that the PFGE method was the most distinguishable tool in identifying clusters of Cronobacter spp. through DNA fingerprinting, and MLST method came second. However, ESTR-1, ESTR-2, ESTR-3, and ESTR-4 were not effective loci for subtyping Cronobacter spp. such that the MLVA method requires further improvement.

Isolation, identification and characterization of Bacillus amyloliquefaciens BZ-6, a bacterial isolate for enhancing oil recovery from oily sludge.

Science.gov (United States)

Liu, Wuxing; Wang, Xiaobing; Wu, Longhua; Chen, Mengfang; Tu, Chen; Luo, Yongming; Christie, Peter

2012-06-01

Over 100 biosurfactant-producing microorganisms were isolated from oily sludge and petroleum-contaminated soil from Shengli oil field in north China. Sixteen of the bacterial isolates produced biosurfactants and reduced the surface tension of the growth medium from 71 to treat oily sludge and the recovery efficiencies of oil from oily sludge were determined. The oil recovery efficiencies of different isolates ranged from 39% to 88%. Bacterial isolate BZ-6 was found to be the most efficient strain and the three phases (oil, water and sediment) were separated automatically after the sludge was treated with the culture medium of BZ-6. Based on morphological, physiological characteristics and molecular identification, isolate BZ-6 was identified as Bacillus amyloliquefaciens. The biosurfactant produced by isolate BZ-6 was purified and analyzed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry. There were four ion peaks representing four different fengycin A homologues. Copyright © 2012. Published by Elsevier Ltd.

Phylogenetic analysis of Hungarian goose parvovirus isolates and vaccine strains.

Science.gov (United States)

Tatár-Kis, Tímea; Mató, Tamás; Markos, Béla; Palya, Vilmos

2004-08-01

Polymerase chain reaction and sequencing were used to analyse goose parvovirus field isolates and vaccine strains. Two fragments of the genome were amplified. Fragment "A" represents a region of VP3 gene, while fragment "B" represents a region upstream of the VP3 gene, encompassing part of the VP1 gene. In the region of fragment "A" the deduced amino acid sequence of the strains was identical, therefore differentiation among strains could be done only at the nucleotide level, which resulted in the formation of three groups: Hungarian, West-European and Asian strains. In the region of fragment "B", separation of groups could be done by both nucleotide and deduced amino acid sequence level. The nucleotide sequences resulted in the same groups as for fragment "A" but with a different clustering pattern among the Hungarian strains. Within the "Hungarian" group most of the recent field isolates fell into one cluster, very closely related or identical to each other, indicating a very slow evolutionary change. The attenuated strains and field isolates from 1979/80 formed a separate cluster. When vaccine strains and field isolates were compared, two specific amino acid differences were found that can be considered as possible markers for vaccinal strains. Sequence analysis of fragment "B" seems to be a suitable method for differentiation of attenuated vaccine strains from virulent strains. Copyright 2004 Houghton Trust Ltd

Characterization of Salmonella enterica Serovar Typhimurium DT104 Isolated from Denmark and Comparison with Isolates from Europe and the United States

DEFF Research Database (Denmark)

Baggesen, Dorte Lau; Sandvang, D.; Aarestrup, Frank Møller

2000-01-01

A total of 136 isolates of Salmonella enterica serovar Typhimurium DT104 from Denmark (n = 93), Germany (n = 10), Italy (n = 4), Spain (n = 5), and the United Kingdom (n = 9) were characterized by antimicrobial resistance analysis, plasmid profiling, pulsed-field gel electrophoresis (PFGE......) with the restriction enzymes XbaI and BlnI, and analysis for the presence of integrons and antibiotic resistance genes. The isolates from Denmark were from nine pig herds, while the isolates from other countries were both of animal and of human origin. All but 10 isolates were resistant to ampicillin, chloramphenicol......, spectinomycin, streptomycin, sulfonamides, and tetracycline. Five isolates from the United Kingdom and Spain were sensitive to all antibiotics examined, whereas four isolates from the United Kingdom and the United States were also resistant to one or more of the antibiotics, namely, gentamicin, neomycin...

A half mode inkjet printed tunable ferrite isolator

KAUST Repository

Ghaffar, Farhan A.

2017-10-24

A novel half mode waveguide based ferrite isolator design is presented in this work. For the first time, tunability of the isolation band is demonstrated for a ferrite isolator. Instead of using the conventional antisymmetric bias the isolator requires a single direction of the magnetic bias field due to the half mode operation. Yttrium Iron Garnet (YIG) is used as the substrate for the device. The metallic walls of the waveguide are realized using inkjet printing. The magnetic biasing applied to the waveguide causes the RF waves to experience negative permeability in one direction of propagation hence providing isolation for this direction. For an applied bias of 3000 Oe, the device provides a maximum isolation figure of merit of 76.7 dB at 7.5 GHz. The isolation band can be controlled by changing the applied magnetostatic bias. As the bias is varied from 1500 Oe to 3500 Oe the center frequency of the isolation band varies from 4.45 GHz to 9 GHz. The measured response of the isolator shows that it can be integrated in any RF system requiring lower cost and good isolation.

Complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from lettuce (Lactuca sativa) originating from a conventional field in Norway.

Science.gov (United States)

Dees, Merete Wiken; Brurberg, May Bente; Lysøe, Erik

2016-12-01

Here, we present the 3,795,952 bp complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from conventionally grown lettuce ( Lactuca sativa ) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017580.

Genetic variations among Mycoplasma bovis strains isolated from Danish cattle

DEFF Research Database (Denmark)

Kusiluka, L.J.M.; Kokotovic, Branko; Ojeniyi, B.

2000-01-01

The genetic heterogeneity of Mycoplasma bovis strains isolated in Denmark over a 17-year period was investigated. Forty-two field strains isolated from different geographic locations and specimens, including strains from 21 herds involved in two outbreaks of M. bovis-induced mastitis, and the type...

Presence of a novel DNA methylation enzyme in methicillin-resistant Staphylococcus aureus isolates associated with pig farming leads to uninterpretable results in standard pulsed-field gel electrophoresis analysis.

NARCIS (Netherlands)

Bens, C.C.; Voss, A.; Klaassen, C.H.W.

2006-01-01

Genomic DNA from methicillin-resistant Staphylococcus aureus isolates recovered from pigs and their caretakers proved resistant to SmaI digestion, leading to uninterpretable results in standard pulsed-field gel electrophoresis. This is the result of a yet unknown restriction/methylation system in

EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin.

Science.gov (United States)

Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Azarnia Tehran, Domenico; Montecucco, Cesare; Barth, Holger

2016-04-01

The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins.

EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin

Science.gov (United States)

Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R.; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

2016-01-01

The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins. PMID:27043629

Diverse modes of galacto-specific carbohydrate recognition by a family 31 glycoside hydrolase from Clostridium perfringens.

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Julie M Grondin

Full Text Available Clostridium perfringens is a commensal member of the human gut microbiome and an opportunistic pathogen whose genome encodes a suite of putative large, multi-modular carbohydrate-active enzymes that appears to play a role in the interaction of the bacterium with mucin-based carbohydrates. Among the most complex of these is an enzyme that contains a presumed catalytic module belonging to glycoside hydrolase family 31 (GH31. This large enzyme, which based on its possession of a GH31 module is a predicted α-glucosidase, contains a variety of non-catalytic ancillary modules, including three CBM32 modules that to date have not been characterized. NMR-based experiments demonstrated a preference of each module for galacto-configured sugars, including the ability of all three CBM32s to recognize the common mucin monosaccharide GalNAc. X-ray crystal structures of the CpGH31 CBM32s, both in apo form and bound to GalNAc, revealed the finely-tuned molecular strategies employed by these sequentially variable CBM32s in coordinating a common ligand. The data highlight that sequence similarities to previously characterized CBMs alone are insufficient for identifying the molecular mechanism of ligand binding by individual CBMs. Furthermore, the overlapping ligand binding profiles of the three CBMs provide a fail-safe mechanism for the recognition of GalNAc among the dense eukaryotic carbohydrate networks of the colonic mucosa. These findings expand our understanding of ligand targeting by large, multi-modular carbohydrate-active enzymes, and offer unique insights into of the expanding ligand-binding preferences and binding site topologies observed in CBM32s.

Molecular characterization of field infectious bursal disease virus isolates from Nigeria

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Ijeoma O. Nwagbo

2016-12-01

Full Text Available Aim: To characterize field isolates of infectious bursal disease virus (IBDV from outbreaks in nine states in Nigeria through reverse transcription polymerase chain reaction (RT-PCR and sequence analysis of portions of the VP2 and VP1 genes and to determine the presence or absence of reassortant viruses. Materials and Methods: A total of 377 bursa samples were collected from 201 suspected IBD outbreaks during 2009 to 2014 from nine states in Nigeria. Samples were subjected to RT-PCR using VP2 and VP1 gene specific primers, and the resulting PCR products were sequenced. Results: A total of 143 samples were positive for IBDV by RT-PCR. These assays amplified a 743 bp fragment from nt 701 to 1444 in the IBDV VP2 hypervariable region (hvVP2 of segment A and a 722 bp fragment from nt 168 to 889 in the VP1 gene of segment B. RT-PCR products were sequenced, aligned and compared with reference IBDV sequences obtained from GenBank. All but one hvVP2 sequence showed similarity to very virulent IBDV (vvIBDV reference strains, yet only 3 of the VP1 67 VP1 sequences showed similarity to the VP1 gene of vvIBDV. Phylogenetic analysis revealed a new lineage of Nigerian reassortant IBDV strains. Conclusion: Phylogenetic analysis of partial sequences of genome segment A and B of IBDV in Nigeria confirmed the existence of vvIBDV in Nigeria. In addition, we noted the existence of reassortant IBDV strains with novel triplet amino acid motifs at positions 145, 146 and 147 in the reassorted Nigerian IBDV.

Electricity-free, sequential nucleic acid and protein isolation.

Science.gov (United States)

Pawlowski, David R; Karalus, Richard J

2012-05-15

Traditional and emerging pathogens such as Enterohemorrhagic Escherichia coli (EHEC), Yersinia pestis, or prion-based diseases are of significant concern for governments, industries and medical professionals worldwide. For example, EHECs, combined with Shigella, are responsible for the deaths of approximately 325,000 children each year and are particularly prevalent in the developing world where laboratory-based identification, common in the United States, is unavailable (1). The development and distribution of low cost, field-based, point-of-care tools to aid in the rapid identification and/or diagnosis of pathogens or disease markers could dramatically alter disease progression and patient prognosis. We have developed a tool to isolate nucleic acids and proteins from a sample by solid-phase extraction (SPE) without electricity or associated laboratory equipment (2). The isolated macromolecules can be used for diagnosis either in a forward lab or using field-based point-of-care platforms. Importantly, this method provides for the direct comparison of nucleic acid and protein data from an un-split sample, offering a confidence through corroboration of genomic and proteomic analysis. Our isolation tool utilizes the industry standard for solid-phase nucleic acid isolation, the BOOM technology, which isolates nucleic acids from a chaotropic salt solution, usually guanidine isothiocyanate, through binding to silica-based particles or filters (3). CUBRC's proprietary solid-phase extraction chemistry is used to purify protein from chaotropic salt solutions, in this case, from the waste or flow-thru following nucleic acid isolation(4). By packaging well-characterized chemistries into a small, inexpensive and simple platform, we have generated a portable system for nucleic acid and protein extraction that can be performed under a variety of conditions. The isolated nucleic acids are stable and can be transported to a position where power is available for PCR amplification

Quantitative Microbial Risk Assessment for in Natural and Processed Cheeses

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Heeyoung Lee

2016-08-01

Full Text Available This study evaluated the risk of Clostridium perfringens (C. perfringens foodborne illness from natural and processed cheeses. Microbial risk assessment in this study was conducted according to four steps: hazard identification, hazard characterization, exposure assessment, and risk characterization. The hazard identification of C. perfringens on cheese was identified through literature, and dose response models were utilized for hazard characterization of the pathogen. For exposure assessment, the prevalence of C. perfringens, storage temperatures, storage time, and annual amounts of cheese consumption were surveyed. Eventually, a simulation model was developed using the collected data and the simulation result was used to estimate the probability of C. perfringens foodborne illness by cheese consumption with @RISK. C. perfringens was determined to be low risk on cheese based on hazard identification, and the exponential model (r = 1.82×10−11 was deemed appropriate for hazard characterization. Annual amounts of natural and processed cheese consumption were 12.40±19.43 g and 19.46±14.39 g, respectively. Since the contamination levels of C. perfringens on natural (0.30 Log CFU/g and processed cheeses (0.45 Log CFU/g were below the detection limit, the initial contamination levels of natural and processed cheeses were estimated by beta distribution (α1 = 1, α2 = 91; α1 = 1, α2 = 309×uniform distribution (a = 0, b = 2; a = 0, b = 2.8 to be −2.35 and −2.73 Log CFU/g, respectively. Moreover, no growth of C. perfringens was observed for exposure assessment to simulated conditions of distribution and storage. These data were used for risk characterization by a simulation model, and the mean values of the probability of C. perfringens foodborne illness by cheese consumption per person per day for natural and processed cheeses were 9.57×10−14 and 3.58×10−14, respectively. These results indicate that probability of C. perfringens

MICROBIOLOGICAL SURVEY OF RETAIL HERBS AND SPICES

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A. Santoro

2009-12-01

Full Text Available In the present study, 80 samples of herbs and spices were analyzed for the presence of Bacillus cereus, Salmonella spp., , Escherichia coli, total and fecal coliforms, Enterobacteriacaee, total mesophilic and psychrophilic aerobic organisms, and fungi. Samples were packaged in polyethylene bags or glass containers.High levels of mesophilic aerobic microorganisms were found in most of the samples. B. cereus was present in 27 samples, Clostrium perfringens was isolated from 3 samples, Salmonella spp. was not detected.

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

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Abraham Landa

2010-01-01

Full Text Available 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, αmethyl-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.

Isolation and screening phosphate solubilizers from composts as biofertilizer

International Nuclear Information System (INIS)

Phua Choo Kwai Hoe; Khairuddin Abdul Rahim; Latiffah Norddin; Abdul Razak Ruslan

2006-01-01

Phosphate solubilizers are miroorganisms that able to solubilize insoluble inorganic phosphate compounds or hydrolyze organic phosphate to inorganic P. Therefore make the P to be available for plant and consequently enhance plant growth and yield. Recently, phosphate solubilizing microorganisms has been shown to play an important role in the biofertilizer industry. Fifty-one bacterial were isolated from eleven composts. Most of the phosphate solubilizers were isolated from natural farming composted compost and normal composting compost. This shows that both of these composts are more suitable to use for phosphate solubilizer isolation compare commercial composts. Fourteen of the isolates were found to be phosphate solubilizers. These isolates produced a clear zone on the phosphate agar plates, showing their potential as biofertilizer. AP3 was significantly produced the largest clear zone compared with other isolates. This indicates that isolate AP 3 could be a good phosphate solubilizer. Thus, their effectiveness in the greenhouse and field should be evaluated. (Author)

Identification and Characterization of Yeast Isolates from Pharmaceutical Waste Water

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Marjeta Recek

2002-01-01

Full Text Available In order to develop an efficient an system for waste water pretreatment, the isolation of indigenous population of microorganisms from pharmaceutical waste water was done. We obtained pure cultures of 16 yeast isolates that differed slightly in colony morphology. Ten out of 16 isolates efficiently reduced COD in pharmaceutical waste water. Initial physiological characterization failed to match the 10 yeast isolates to either Pichia anomala or Pichia ciferrii. Restriction analysis of rDNA (rDNA-RFLP using three different restriction enzymes: HaeIII, MspI and CfoI, showed identical patterns of the isolates and Pichia anomala type strain. Separation of chromosomal DNAs of yeast isolates by the pulsed field gel electrophoresis revealed that the 10 isolates could be grouped into 6 karyotypes. Growth characteristics of the 6 isolates with distinct karyotypes were then studied in batch cultivation in pharmaceutical waste water for 80 hours.

Phylogenetic Analysis of Apple scar skin viroid Isolates in Korea

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Kang Hee Cho

2015-12-01

Full Text Available To identify genome sequences of Apple scar skin viroid (ASSVd isolates in Korea, the field survey was performed from ‘Hongro’ apple orchards located in eight sites in South Korea (Bongwha, Cheongsong, Dangjin, Gimchoen, Muju, Mungyeong, Suwon, and Yeongwol. ASSVd was detected by RT-PCR and PCR fragments were cloned into cloning vector. Full-length viral genomes of eight ASSVd isolates were sequenced and compared with 21 isolates reported previously from Korea, India, China, Japan and Greece. Eight isolates in this study showed 92.2-99.7% nucleotide sequence identities with those reported previously. Phylogenetic analysis showed that seven isolates reported in this study belong to the same group distinct from other groups.

Probiotic properties of Lactobacillus strains isolated from the feces of breast-fed infants and Taiwanese pickled cabbage.

Science.gov (United States)

Wang, Chung-Yi; Lin, Pei-Rong; Ng, Chang-Chai; Shyu, Yuan-Tay

2010-12-01

This study assessed potential probiotic Lactobacillus strains isolated from the feces of breast-fed infants and from Taiwanese pickled cabbage for their possible use in probiotic fermented foods by evaluating their (i) in vitro adhesive ability, resistance to biotic stress, resistance to pathogenic bacteria, and production of β-galactosidase; (ii) milk technological properties; and (iii) in vivo adhesive ability, intestinal survival and microbial changes during and after treatment. Five Lactobacillus isolates identified as Lactobacillus reuteri F03, Lactobacillus paracasei F08, Lactobacillus rhamnosus F14, Lactobacillus plantarum C06, and Lactobacillus acidophilus C11 that showed resistance to gastric juice and bile salts were selected for further evaluation of their probiotic properties. All the strains demonstrated the ability to adhere to Caco-2 cells, particularly, strain L. plantarum C06 and L. reuteri F03 showed satisfactory abilities, which were similar to that of the reference strain L. rhamnosus GG. The strains L. paracasei F08 and L. acidophilus C11 had the highest β-galactosidase activity. Most of the strains were resistant to aminoglycosides and vancomycin but sensitive to ampicillin, erythromycin, and penicillin. All the 5 strains elicited antibacterial activity against both Gram-positive (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) and -negative (Escherichia coli and Salmonella enterica) pathogens. Moreover, the strains L. reuteri F03, L. paracasei F08, and L. plantarum C06 could grow rapidly in milk without nutrient supplementation and reached 10⁸ cfu/mL after 24 h of fermentation at 37 °C. The viable cell counts of the 3 strains remained above 10⁷ cfu/mL after 21 d of storage at 4 °C. In the animal feeding trial, the number of intestinal lactobacilli increased significantly after administration of milk fermented with the 3 strains, and the counts of fecal coliforms and Clostridium perfringens were markedly reduced

Presence of a Novel DNA Methylation Enzyme in Methicillin-Resistant Staphylococcus aureus Isolates Associated with Pig Farming Leads to Uninterpretable Results in Standard Pulsed-Field Gel Electrophoresis Analysis

OpenAIRE

Bens, Corina C. P. M.; Voss, Andreas; Klaassen, Corné H. W.

2006-01-01

Genomic DNA from methicillin-resistant Staphylococcus aureus isolates recovered from pigs and their caretakers proved resistant to SmaI digestion, leading to uninterpretable results in standard pulsed-field gel electrophoresis. This is the result of a yet unknown restriction/methylation system in the genus Staphylococcus with the recognition sequence CCNGG.

Isolation of entomopathogenic nematodes and control of ...

African Journals Online (AJOL)

Jaime Ruiz

when a new NE is isolated from field samples, laboratory assessments of ..... Tanks to Amanda Hodson, University of California at. Davis, for carrying out ... Manual of techniques in insect pathology. Academic Press, New York. Koppenhöfer A ...

Optical isolation by Faraday rotator

International Nuclear Information System (INIS)

Kasai, Takeshi; Matsushima, Isao; Nemoto, Fusashi; Yano, Masaaki

1984-01-01

Three Faraday rotators designed as optical isolators in a high power glass laser system are described. The spatial fluctuation of applied magnetic field is less than 1% throughout the Faraday glass rod. The Faraday rotators transmit more than 80% of the forward-going laser light and reject more than 96% of the backward-going light. (author)

Multi-Wavelength Polarimetry of Isolated Neutron Stars

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Roberto P. Mignani

2018-03-01

Full Text Available Isolated neutron stars are known to be endowed with extreme magnetic fields, whose maximum intensity ranges from 10 12 – 10 15 G, which permeates their magnetospheres. Their surrounding environment is also strongly magnetized, especially in the compact nebulae powered by the relativistic wind from young neutron stars. The radiation from isolated neutron stars and their surrounding nebulae is, thus, supposed to bring a strong polarization signature. Measuring the neutron star polarization brings important information about the properties of their magnetosphere and of their highly magnetized environment. Being the most numerous class of isolated neutron stars, polarization measurements have been traditionally carried out for radio pulsars, hence in the radio band. In this review, I summarize multi-wavelength linear polarization measurements obtained at wavelengths other than radio both for pulsars and other types of isolated neutron stars and outline future perspectives with the upcoming observing facilities.

Genetic Diversity of Pectobacterium carotovorum subsp. brasiliensis Isolated in Korea

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Dong Hwan Lee

2014-06-01

Full Text Available The plant pathogenic bacterial genus Pectobacteirum consists of heterogeneous strains. The P. carotovorum species is a complex strain showing divergent characteristics, and a new subspecies named P. carotovorum subsp. brasiliensis has been identified recently. In this paper, we re-identified the P. carotovorum subsp. brasiliensis isolates from those classified under the subspecies carotovorum and newly isolated P. carotovorum subsp. brasiliensis strains. All isolates were able to produce plant cell-wall degrading enzymes such as pectate lyase, polygalacturonase, cellulase and protease. We used genetic and biochemical methods to examine the diversity of P. carotovorum subsp. brasiliensis isolates, and found genetic diversity within the brasiliensis subsp. isolates in Korea. The restriction fragment length polymorphism analysis based on the recA gene revealed a unique pattern for the brasiliensis subspecies. The Korean brasiliensis subsp. isolates were divided into four clades based on pulsed-field gel electrophoresis. However, correlations between clades and isolated hosts or year could not be found, suggesting that diverse brasiliensis subsp. isolates existed.

Bacterial spores as possible contaminants of biomedical materials and devices. [Bacillus anthracis, clostridium botulinum, C. perfringens, C. tetani

Energy Technology Data Exchange (ETDEWEB)

Grecz, N; Kang, T

1973-01-01

Destruction of spores on biomedical devices in drugs, and biologicals is essential for prevention of infection of patients with pathogenic sporeformers. Of particular concern are Clostridium tetani, C. perfringens, C. botulinum, Bacillus anthracis and other sporeforming pathogens. Spores are ubiquitous in nature and contamination of biomedical devices varies depending on manufacturing process, handling, raw materials and other variables. In the last 20 years the number of cases per year of specific notifiable diseases in the United States was as follows: tetanus, 120 to 500 cases, botulism, 7 to 47 cases, and anthrax, 2 to 10 cases. Gas gangrene is caused by a mixed flora consisting predominantly of sporeformers. C botulinum, which usually acts as saprophytic agent of food poisoning, may also initiate pathogenic processes; there are nine cases on record in the United States of botulism wound infections almost half of which ended in death. The spores of these organisms are distinguished by high radiation resistance and their erradication often requires severe radiation treatments. Representative bacterial spores in various suspending media show D/sub 10/ values (dose necessary to destroy 90 percent of a given population) ranging from approximately 0.1 to 0.4 Mrad. Some viruses show D/sub 10/ values up to greater than 1 Mrad. The D/sub 10/-values of spores vary depending on physical, chemical and biological factors. This variability is important in evaluation and selection of biological indicator organisms. Radiation sterilization of biomedical devices and biomedical materials must provide safety from infectious microorganisms including radiation resistant spores and viruses.

Prevalence of antimicrobial resistance among Salmonella isolates from chicken in China.

Science.gov (United States)

Lu, Yan; Wu, Cong-Ming; Wu, Guo-Juan; Zhao, Hong-Yu; He, Tao; Cao, Xing-Yuan; Dai, Lei; Xia, Li-Ning; Qin, Shang-Shang; Shen, Jian-Zhong

2011-01-01

We evaluated the antimicrobial resistance of Salmonella isolated in 2008 from a chicken hatchery, chicken farms, and chicken slaughterhouses in China. A total of 311 Salmonella isolates were collected from the three sources, and two serogroups of Salmonella were detected, of which 133 (42.8%) consisted of Salmonella indiana and 178 (57.2%) of Salmonella enteritidis. The lowest percentage of S. indiana isolates was found in the chicken hatchery (4.2%), followed by the chicken farms (54.9%) and the slaughterhouses (71.4%). More than 80% of the S. indiana isolates were highly resistant to ampicillin (97.7%), amoxicillin/clavulanic acid (87.9%), cephalothin (87.9%), ceftiofur (85.7%), chloramphenicol (84.9%), florfenicol (90.9%), tetracycline (97.7%), doxycycline (98.5%), kanamycin (90.2%), and gentamicin (92.5%). About 60% of the S. indiana isolates were resistant to enrofloxacin (65.4%), norfloxacin (78.9%), and ciprofloxacin (59.4%). Of the S. indiana isolates, 4.5% were susceptible to amikacin and 5.3% to colistin. Of the S. enteritidis isolates, 73% were resistant to ampicillin, 33.1% to amoxicillin/clavulanic acid, 66.3% to tetracycline, and 65.3% to doxycycline, whereas all of these isolates were susceptible to the other drugs used in the study. The S. indiana isolates showed resistance to 16 antimicrobial agents. Strains of Salmonella (n = 108) carrying the resistance genes floR, aac(6')-Ib-cr, and bla(TEM) were most prevalent among the 133 isolates of S. indiana, at a frequency of 81.2%. The use of pulsed-field gel electrophoresis to analyze the S. indiana isolates that showed similar antimicrobial resistance patterns and carried resistance genes revealed six genotypes of these organisms. Most of these isolates had the common pulsed-field gel electrophoresis patterns found in the chicken hatchery, chicken farms, and slaughterhouses, suggesting that many multidrug-resistant isolates of S. indiana prevailed in the three sources. Some of these isolates were

Complete genome sequence of the biofilm-forming Microbacterium sp. strain BH-3-3-3, isolated from conventional field-grown lettuce (Lactuca sativa) in Norway.

Science.gov (United States)

Dees, Merete Wiken; Brurberg, May Bente; Lysøe, Erik

2017-03-01

The genus Microbacterium contains bacteria that are ubiquitously distributed in various environments and includes plant-associated bacteria that are able to colonize tissue of agricultural crop plants. Here, we report the 3,508,491 bp complete genome sequence of Microbacterium sp. strain BH-3-3-3, isolated from conventionally grown lettuce ( Lactuca sativa ) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017674.

Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural soil

DEFF Research Database (Denmark)

Rønhede, S.; Jensen, Bo; Rosendahl, Søren

2005-01-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N......Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl...

Biological control of phytopathogenic fungi by endophytic actinomycetes isolated from maize (Zea mays L.

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Francisco Gheler Costa

2013-12-01

Full Text Available This work aimed a survey on the biodiversity of maize endophytic actinomycete, and an evaluation of their potential to control the phytopathogenic fungi. From several regions of São Paulo state, 40 strains were isolated from the healthy maize plants. The identification of these strains, based on morphological properties and fatty acid methyl ester (FAME profile showed that most of them belonged to the Streptomyces genus. These isolates were first screened for the growth inhibition of phytopathogenic fungi and results showed that all the isolate were able to inhibit the development of at least one tested pathogen. Two selected isolates were then evaluated for the control of P. aphanidermatum in cucumber (Cucumis sativa L. under greenhouse conditions. Isolate 16R3B was able to reduce up to 71% damping-off incidence whereas isolate 14F1D/2 reduced the disease incidence by 36%. Damping- off control in cucumber, mainly for the isolate 16R3B, suggested for its use in greenhouse cucumber producing fields and to be tested in field trials.

Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

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Arastoo Badoei-Dalfard

2016-09-01

Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

Designing Security-Hardened Microkernels For Field Devices

Science.gov (United States)

Hieb, Jeffrey; Graham, James

Distributed control systems (DCSs) play an essential role in the operation of critical infrastructures. Perimeter field devices are important DCS components that measure physical process parameters and perform control actions. Modern field devices are vulnerable to cyber attacks due to their increased adoption of commodity technologies and that fact that control networks are no longer isolated. This paper describes an approach for creating security-hardened field devices using operating system microkernels that isolate vital field device operations from untrusted network-accessible applications. The approach, which is influenced by the MILS and Nizza architectures, is implemented in a prototype field device. Whereas, previous microkernel-based implementations have been plagued by poor inter-process communication (IPC) performance, the prototype exhibits an average IPC overhead for protected device calls of 64.59 μs. The overall performance of field devices is influenced by several factors; nevertheless, the observed IPC overhead is low enough to encourage the continued development of the prototype.

Improved Control Strategy for T-type Isolated DC/DC Converters

DEFF Research Database (Denmark)

Liu, Dong; Deng, Fujin; Wang, Yanbo

2017-01-01

T-type isolated DC/DC converters have recently attracted attention due to their numerous advantages, including few components, low cost, and symmetrical operation of transformers. This study proposes an improved control strategy for increasing the efficiency of T-type isolated DC/DC converters....... Under the proposed strategy, the primary circulating current flows through the auxiliary switches (metal–oxide–semiconductor field-effect transistors) instead of their body diodes in free-wheeling periods. Such feature can reduce conduction losses, thereby improving the efficiency of T-type isolated DC...

Stability and fitness of pyraclostrobin- and boscalid-resistant phenotypes in field isolates of Botrytis cinerea from apple.

Science.gov (United States)

Kim, Y K; Xiao, C L

2011-11-01

Phenotype stability, fitness, and competitive ability of pyraclostrobin- and boscalid-resistant isolates of Botrytis cinerea from apple were investigated. Stability of resistance was determined after consecutive transfers on potato dextrose agar (PDA) or being cycled on apple fruit. In vitro fitness components mycelial growth, osmotic sensitivity, conidial germination, and sporulation were evaluated on agar media. Pathogenicity, virulence and sporulation on apple fruit were evaluated at both 20 and 0°C. Competition between fungicide-resistant and -sensitive isolates on apple fruit also was evaluated. Resistance to the two fungicides was retained at levels similar to that of the initial generation after 20 and 10 transfers on PDA and five and three disease cycles on apple fruit at 20 and 0°C, respectively. Great variability in individual fitness components tested was observed among isolates within the same phenotype groups either sensitive or resistant to the fungicides but, when compared as phenotype groups, there were no significant differences in the mean values of these fitness components between resistant and sensitive phenotypes except that the phenotype resistant only to boscalid produced fewer conidia in vitro than sensitive isolates. Resistant isolates were as pathogenic and virulent on apple fruit as sensitive isolates. There was no significant correlation between the values of individual fitness components tested and the level of resistance to pyraclostrobin or boscalid, except that virulence at 20°C positively correlated with the level of resistance to the two fungicides. The final frequency of pyraclostrobin-resistant individuals in the populations was significantly decreased compared with the initial generation and no boscalid-resistant individuals were detected after four disease cycles on apple fruit inoculated with a pair mixture of a dual-sensitive isolate and one isolate each of the three phenotypes resistant to pyraclostrobin, boscalid, or

Isolated systems with wind power. Main report

Energy Technology Data Exchange (ETDEWEB)

Lundsager, P.; Bindner, H.; Clausen, N.E.; Frandsen, S.; Hansen, L.H.; Hansen, J.C.

2001-06-01

The overall objective of this research project is to study the development of methods and guidelines rather than 'universal solutions' for the use of wind energy in isolated communities. The main specific objective of the project is to develop and present a more unified and generally applicable approach for assessing the technical and economical feasibility of isolated power supply systems with wind energy. As a part of the project the following tasks were carried out: Review of literature, field measurements in Egypt, development of an inventory of small isolated systems, overview of end-user demands, analysis of findings and development of proposed guidelines. The project is reported in one main report and four topical reports, all of them issued as Risoe reports. This is the Main Report Risoe-R-1256, summing up the activities and findings of the project and outlining an Implementation Strategy for Isolated Systems with Wind Power, applicable for international organisations such as donor agencies and development banks. (au)

Genotyping of Indian antigenic, vaccine, and field Brucella spp. using multilocus sequence typing.

Science.gov (United States)

Shome, Rajeswari; Krithiga, Natesan; Shankaranarayana, Padmashree B; Jegadesan, Sankarasubramanian; Udayakumar S, Vishnu; Shome, Bibek Ranjan; Saikia, Girin Kumar; Sharma, Narendra Kumar; Chauhan, Harshad; Chandel, Bharat Singh; Jeyaprakash, Rajendhran; Rahman, Habibur

2016-03-31

Brucellosis is one of the most important zoonotic diseases that affects multiple livestock species and causes great economic losses. The highly conserved genomes of Brucella, with > 90% homology among species, makes it important to study the genetic diversity circulating in the country. A total of 26 Brucella spp. (4 reference strains and 22 field isolates) and 1 B. melitensis draft genome sequence from India (B. melitensis Bm IND1) were included for sequence typing. The field isolates were identified by biochemical tests and confirmed by both conventional and quantitative polymerase chain reaction (qPCR) targeting bcsp 31Brucella genus-specific marker. Brucella speciation and biotyping was done by Bruce ladder, probe qPCR, and AMOS PCRs, respectively, and genotyping was done by multilocus sequence typing (MLST). The MLST typing of 27 Brucella spp. revealed five distinct sequence types (STs); the B. abortus S99 reference strain and 21 B. abortus field isolates belonged to ST1. On the other hand, the vaccine strain B. abortus S19 was genotyped as ST5. Similarly, B. melitensis 16M reference strain and one B. melitensis field isolate were grouped into ST7. Another B. melitensis field isolate belonged to ST8 (draft genome sequence from India), and only B. suis 1330 reference strain was found to be ST14. The sequences revealed genetic similarity of the Indian strains to the global reference and field strains. The study highlights the usefulness of MLST for typing of field isolates and validation of reference strains used for diagnosis and vaccination against brucellosis.

7 CFR 201.76 - Minimum Land, Isolation, Field, and Seed Standards.

Science.gov (United States)

2010-01-01

... 2,500 0.5 7 1 825(59 251.46m) 27 1,250 1.0 Onion 7 1 5,280(59 1,609.36m) 22 200 0.0 7 1 2,640(59 804... varieties of dissimilar adaptation and establishment of the stand for the production of the Certified class of seed. 3 Isolation distance for certified seed production shall be at least 500 feet (152.07m) from...

Xerophilic mycopopulations isolated from rapeseeds (Brassica napus

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Škrinjar Marija M.

2013-01-01

Full Text Available This paper presents the results of an investigation related to mycological populations of rapeseed samples produced in the Institute of Field and Vegetable Crops in Novi Sad (location: Rimski Šančevi, Novi Sad, with a special emphasis on the potentially toxigenic mycopopulations. Mycological investigations were performed on the samples that were treated with 4% solution of Na-hypochlorite, and on the ones that were not submitted to this treatment. Isolation and determination of total mould count was carried out using Dichloran Glycerol Agar (DG18. The identification of isolated moulds was done according to modern keys for fungal determination. From 20 untreated tested samples, 17 were contaminated with moulds (10.0 to 4.7x102 cfu/g. When the samples were treated with 4% solution of Na-hypochlorite, moulds were isolated only form 4 samples, and the total mould count ranged from 10.0 to 60.0 cfu/g. In the isolated mycopopulations, xerophilic moulds dominated, especially those from the genera Aspergillus, Eurotium and Penicillium. In the isolated mycopopulations, high degree of isolated species belonged to toxigenic species from the genera Alternaria, Aspergillus, Fusarium, Eurotium and Penicillium. [Projekat Ministarstva nauke Republike Srbije, br. III46009 i br.TR31025

Profound improvements of isolated microspores culture techniques ...

African Journals Online (AJOL)

We studied the effects of sampling stages, physical conditions (like temperature), culture conditions, embryo long-distance transportation methodology and plantlet regeneration on isolated microspores from donor plants in field. Results indicated that if microspores were sampled in bud stage instead of blooming stage to ...

Isolation, characterization and toxicity of native Bacillus thuringiensis isolates from different hosts and habitats in Iran

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Ghassemi-Kahrizeh Akbar

2017-09-01

Full Text Available Bacillus thuringiensis is a Gram-positive, aerobic, facultative anaerobic and endospore-forming bacterium. Different strains of this species have the ability to produce parasporal crystalline inclusions which are toxic to larvae of different insect orders and other invertebrates and cause rapid death of the host. To determine the importance of this species in microbial control, we collected native strains and studied their virulence on the diamondback moth, Plutella xylostella. More than 148 samples were collected from Alborz, Guilan and Mazandaran Provinces. Experimental samples, including soil samples from forests, fruit gardens, agricultural fields, diseased and dead larvae, were transferred to a laboratory in sterile plastic containers. For evaluating B. thuringiensis isolates virulence, a cabbage leaf dip method with 106 cell · ml−1 concentration of various Bt isolates was applied to diamondback moths. Larval mortality was recorded 72 h after treatment. Based on bioassay results, all isolates were classified into three high, medium and low virulence groups. Protein level characterization based on the SDS-PAGE gel analysis showed that two isolates from a high virulence group have proteins of high molecular masses of 121 and 109 kDa. Results revealed that there is a positive correlation between protein masses and virulence of isolates. In addition, this research introduced nine strains that are highly toxic to P. xylostella and would be valuable as insecticidal agents for controlling lepidopteran pests.

Rarity of isolated pulmonary embolism and acute aortic syndrome occurring outside of the field of view of dedicated coronary CT angiography

International Nuclear Information System (INIS)

Lee, Hwa Yeon; Song, In Sup; Yoo, Seung Min; Rho, Ji Young; Moon, Jae Youn; Kim, In Jai; Lim, Sang Wook; Sung, Jung Hoon; Cha, Dong Hun; White, Charles S.

2011-01-01

Background Although triple rule-out CT angiography (TRO) to simultaneously evaluate acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic syndrome (AAS) is increasingly used in many institutions, TRO is inevitably associated with increased radiation exposure due to extended z-axis coverage compared with dedicated coronary CT angiography (DCTA). Purpose To determine the frequency of exclusion of findings of AAS, PE, and significant incidental non-cardiac pathology that may be the cause of acute chest pain when using a restricted DCTA field of view (FOV). Material and Methods We retrospectively reviewed CT images and charts of 103 patients with acute PE and 50 patients with AAS. Either non-ECG gated dedicated pulmonary or aortic CT angiography was performed using 16- or 64-slice multidetector CT (MDCT). We analyzed the incidence of isolated PE, AAS, or significant non-cardiac pathology outside of DCTA FOV (i.e. from tracheal carina to the base of heart). Results There were two cases of isolated PE (2/103, 1.9%) excluded from the FOV of DCTA. One case of PE was isolated to the subsegmental pulmonary artery in the posterior segment of the right upper lobe. In the second case, pulmonary embolism in the left main pulmonary artery was located out of the FOV of DCTA because the left main pulmonary artery was retracted upwardly by fibrotic scar in the left upper lobe due to prior tuberculosis. There was no case of AAS and significant non-cardiac pathology excluded from the FOV of DCTA. AAS (n = 50) consisted of penetrating atherosclerotic ulcer (n = 7), intramural hematoma (n = 5) and aortic dissection (n = 38). Conclusion As isolated PE, AAS, and significant non-cardiac pathology outside of the DCTA FOV rarely occur, DCTA may replace TRO in the evaluation of patients with non-specific acute chest pain and a low pre-test probability of PE or aortic dissection

Rarity of isolated pulmonary embolism and acute aortic syndrome occurring outside of the field of view of dedicated coronary CT angiography

Energy Technology Data Exchange (ETDEWEB)

Lee, Hwa Yeon; Song, In Sup (Dept. of Diagnostic Radiology Chung-Ang Univ. College of Medicine, Seoul (Korea, Republic of)); Yoo, Seung Min; Rho, Ji Young (Dept. of Diagnostic Radiology CHA Medical Univ. Hospital, Bundang (Korea, Republic of)), email: smyoo68@hanmail.net; Moon, Jae Youn; Kim, In Jai; Lim, Sang Wook; Sung, Jung Hoon; Cha, Dong Hun (Dept. of Cardiology CHA Medical Univ. Hospital, Bundang (Korea, Republic of)); White, Charles S. (Dept. of Diagnostic Radiology Univ. of Maryland, Baltimore (United States))

2011-05-15

Background Although triple rule-out CT angiography (TRO) to simultaneously evaluate acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic syndrome (AAS) is increasingly used in many institutions, TRO is inevitably associated with increased radiation exposure due to extended z-axis coverage compared with dedicated coronary CT angiography (DCTA). Purpose To determine the frequency of exclusion of findings of AAS, PE, and significant incidental non-cardiac pathology that may be the cause of acute chest pain when using a restricted DCTA field of view (FOV). Material and Methods We retrospectively reviewed CT images and charts of 103 patients with acute PE and 50 patients with AAS. Either non-ECG gated dedicated pulmonary or aortic CT angiography was performed using 16- or 64-slice multidetector CT (MDCT). We analyzed the incidence of isolated PE, AAS, or significant non-cardiac pathology outside of DCTA FOV (i.e. from tracheal carina to the base of heart). Results There were two cases of isolated PE (2/103, 1.9%) excluded from the FOV of DCTA. One case of PE was isolated to the subsegmental pulmonary artery in the posterior segment of the right upper lobe. In the second case, pulmonary embolism in the left main pulmonary artery was located out of the FOV of DCTA because the left main pulmonary artery was retracted upwardly by fibrotic scar in the left upper lobe due to prior tuberculosis. There was no case of AAS and significant non-cardiac pathology excluded from the FOV of DCTA. AAS (n = 50) consisted of penetrating atherosclerotic ulcer (n = 7), intramural hematoma (n = 5) and aortic dissection (n = 38). Conclusion As isolated PE, AAS, and significant non-cardiac pathology outside of the DCTA FOV rarely occur, DCTA may replace TRO in the evaluation of patients with non-specific acute chest pain and a low pre-test probability of PE or aortic dissection

Genome sequence analysis of five Canadian isolates of strawberry mottle virus reveals extensive intra-species diversity and a longer RNA2 with increased coding capacity compared to a previously characterized European isolate.

Science.gov (United States)

Bhagwat, Basdeo; Dickison, Virginia; Ding, Xinlun; Walker, Melanie; Bernardy, Michael; Bouthillier, Michel; Creelman, Alexa; DeYoung, Robyn; Li, Yinzi; Nie, Xianzhou; Wang, Aiming; Xiang, Yu; Sanfaçon, Hélène

2016-06-01

In this study, we report the genome sequence of five isolates of strawberry mottle virus (family Secoviridae, order Picornavirales) from strawberry field samples with decline symptoms collected in Eastern Canada. The Canadian isolates differed from the previously characterized European isolate 1134 in that they had a longer RNA2, resulting in a 239-amino-acid extension of the C-terminal region of the polyprotein. Sequence analysis suggests that reassortment and recombination occurred among the isolates. Phylogenetic analysis revealed that the Canadian isolates are diverse, grouping in two separate branches along with isolates from Europe and the Americas.

Isolation of a nitrate-reducing bacteria strain from oil field brine and ...

African Journals Online (AJOL)

A nitrate-reducing bacteria (NRB) strain with vigorous growth, strong nitrate reduction ability, strain B9 2-1, was isolated from Suizhong36-1 oilfield, its routine identification and analysis of 16S rRNA and also the competitive inhibition experiments with the enrichment of sulfate-reducing bacteria (SRB) were carried out.

Characterization of Salmonella Typhimurium isolates associated with septicemia in swine

Science.gov (United States)

Bergeron, Nadia; Corriveau, Jonathan; Letellier, Ann; Daigle, France; Quessy, Sylvain

2010-01-01

Salmonella Typhimurium is frequently isolated from pigs and may also cause enteric disease in humans. In this study, 33 isolates of S. Typhimurium associated with septicemia in swine (CS) were compared to 33 isolates recovered from healthy animals at slaughter (WCS). The isolates were characterized using phenotyping and genotyping methods. For each isolate, the phage type, antimicrobial resistance, and pulsed-field gel electrophoresis (PFGE) DNA profiles were determined. In addition, the protein profiles of each isolate grown in different conditions were studied by Coomassie Blue-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot. Various phage types were identified. The phage type PT 104 represented 36.4% of all isolates from septicemic pigs. Resistance to as many as 12 antimicrobial agents, including some natural resistances, was found in isolates from CS and WCS. Many genetic profiles were identified among the PT 104 phage types. Although it was not possible to associate one particular protein with septicemic isolates, several highly immunogenic proteins, present in all virulent isolates and in most isolates from clinically healthy animals, were identified. These results indicated that strains associated with septicemia belong to various genetic lineages that can also be recovered from asymptomatic animals at the time of slaughter. PMID:20357952

The index of a vector field under blow ups

International Nuclear Information System (INIS)

Seade, J.

1991-08-01

A useful technique when studying the behaviour of holomorphic vector fields around their isolated singularities is that of blowing up the singular points. On the other hand, the most basic invariant of a vector field with isolated singularities is its local index, as defined by Poincare and Hopf. It is thus natural to ask how does the index of a vector field behaves under blowing ups? The purpose of this work is to study and answer this question, by taking a rather general point of view and bearing in mind that complex manifolds have a powerful birational invariant, the Todd genus. 20 refs

Seismic Isolation Studies and Applications for Nuclear Facilities

International Nuclear Information System (INIS)

Choun, Young Sun

2005-01-01

Seismic isolation, which is being used worldwide for buildings, is a well-known technology to protect structures from destructive earthquakes. In spite of the many potential advantages of a seismic isolation, however, the applications of a seismic isolation to nuclear facilities have been very limited because of a lack of sufficient knowledge about the isolation practices. The most important advantage of seismic isolation applications in nuclear power plants is that the safety and reliability of the plants can be remarkably improved through the standardization of the structures and equipment regardless of the seismic conditions of the sites. The standardization of structures and equipment will reduce the capital cost and design/construction schedule for future plants. Also, a seismic isolation can facilitate decoupling of the design and development for equipment, piping, and components due to the use of the generic in-structure response spectra associated with the standardized plant. Moreover, a seismic isolation will improve the plant safety margin against the design basis earthquake (DBE) as well as a beyond design basis seismic event due to its superior seismic performance. A number of seismic isolation systems have been developed and tested since 1970s, and some of them have been applied to conventional structures in several countries of high seismicity. In the nuclear field, there have been many studies on the applicability of such seismic isolation systems, but the application of a seismic isolation is very limited. Currently, there are some discussions on the application of seismic isolation systems to nuclear facilities between the nuclear industries and the regulatory agencies in the U.S.. In the future, a seismic isolation for nuclear facilities will be one of the important issues in the nuclear industry. This paper summarizes the past studies and applications of a seismic isolation in the nuclear industry

Highly Diverse Endophytic and Soil Fusarium oxysporum Populations Associated with Field-Grown Tomato Plants

Science.gov (United States)

Demers, Jill E.; Gugino, Beth K.

2014-01-01

The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants. Included in this total were 112 isolates from the stems of all 32 plants, a niche that has not been previously included in F. oxysporum population genetics studies. Isolates were characterized using the DNA sequence of the translation elongation factor 1α gene. A diverse population of 26 sequence types was found, although two sequence types represented nearly two-thirds of the isolates studied. The sequence types were placed in different phylogenetic clades within F. oxysporum, and endophytic isolates were not monophyletic. Multiple sequence types were found in all plants, with an average of 4.2 per plant. The population compositions differed between the two fields but not between soil samples within each field. A certain degree of differentiation was observed between populations associated with different tomato cultivars, suggesting that the host genotype may affect the composition of plant-associated F. oxysporum populations. No clear patterns of genetic differentiation were observed between endophyte populations and soil populations, suggesting a lack of specialization of endophytic isolates. PMID:25304514

Field avian metapneumovirus evolution avoiding vaccine induced immunity.

Science.gov (United States)

Catelli, Elena; Lupini, Caterina; Cecchinato, Mattia; Ricchizzi, Enrico; Brown, Paul; Naylor, Clive J

2010-01-22

Live avian metapneumovirus (AMPV) vaccines have largely brought turkey rhinotracheitis (TRT) under control in Europe but unexplained outbreaks still occur. Italian AMPV longitudinal farm studies showed that subtype B AMPVs were frequently detected in turkeys some considerable period after subtype B vaccination. Sequencing showed these to be unrelated to the previously applied vaccine. Sequencing of the entire genome of a typical later isolate showed numerous SH and G protein gene differences when compared to both a 1987 Italian field isolate and the vaccine in common use. Experimental challenge of vaccinated birds with recent virus showed that protection was inferior to that seen after challenge with the earlier 1987 isolate. Field virus had changed in key antigenic regions allowing replication and leading to disease in well vaccinated birds.

Isolated Early-type Galaxies in the 2dFGRS

Science.gov (United States)

Fuse, Christopher R.; Lamir, C.

2014-01-01

Isolated galaxies are systems that have experienced limited external perturbations, thus the properties of these galaxies are largely due to internal processes. The features of isolated early-type galaxies (IEGs) provide a baseline from which to compare early-type systems residing in higher-density environments. We use the Two-Degree Field Galaxy Redshift Survey (2dFGRS) and the NASA Extragalactic Database (NED) to identify IEGs in the nearby universe. Search criteria in the 2dFGRS were chosen to insure that the IEGs have remained separated from neighboring galaxies for the majority of their lifetimes. Isolated galaxies are chosen utilizing a minimum projected physical separation of 1 Mpc from any neighboring non-dwarf galaxy brighter than Mb = -16.5 mags. A minimum redshift separation of 350 km/s between a candidate galaxy and a neighboring was imposed to further insure the candidate’s isolation. Early results of the search for isolated early-type galaxies in the southern sky are presented.

Suitability of the molecular subtyping methods intergenic spacer region, direct genome restriction analysis, and pulsed-field gel electrophoresis for clinical and environmental Vibrio parahaemolyticus isolates.

Science.gov (United States)

Lüdeke, Catharina H M; Fischer, Markus; LaFon, Patti; Cooper, Kara; Jones, Jessica L

2014-07-01

Vibrio parahaemolyticus is the leading cause of infectious illness associated with seafood consumption in the United States. Molecular fingerprinting of strains has become a valuable research tool for understanding this pathogen. However, there are many subtyping methods available and little information on how they compare to one another. For this study, a collection of 67 oyster and 77 clinical V. parahaemolyticus isolates were analyzed by three subtyping methods--intergenic spacer region (ISR-1), direct genome restriction analysis (DGREA), and pulsed-field gel electrophoresis (PFGE)--to determine the utility of these methods for discriminatory subtyping. ISR-1 analysis, run as previously described, provided the lowest discrimination of all the methods (discriminatory index [DI]=0.8665). However, using a broader analytical range than previously reported, ISR-1 clustered isolates based on origin (oyster versus clinical) and had a DI=0.9986. DGREA provided a DI=0.9993-0.9995, but did not consistently cluster the isolates by any identifiable characteristics (origin, serotype, or virulence genotype) and ∼ 15% of isolates were untypeable by this method. PFGE provided a DI=0.9998 when using the combined pattern analysis of both restriction enzymes, SfiI and NotI. This analysis was more discriminatory than using either enzyme pattern alone and primarily grouped isolates by serotype, regardless of strain origin (clinical or oyster) or presence of currently accepted virulence markers. These results indicate that PFGE and ISR-1 are more reliable methods for subtyping V. parahemolyticus, rather than DGREA. Additionally, ISR-1 may provide an indication of pathogenic potential; however, more detailed studies are needed. These data highlight the diversity within V. parahaemolyticus and the need for appropriate selection of subtyping methods depending on the study objectives.

Generation of isolated attosecond pulses using a plasmonic funnel-waveguide

International Nuclear Information System (INIS)

Choi, Joonhee; Kim, Seungchul; Park, In-Yong; Lee, Dong-Hyub; Han, Seunghwoi; Kim, Seung-Woo

2012-01-01

We theoretically investigated the possibility of generating attosecond pulses by means of plasmonic field enhancement induced in a nano-structured metallic funnel-waveguide. This study was motivated by our recent experimental demonstration of ultrashort extreme-ultraviolet (EUV) pulses using the same type of three-dimensional waveguides. Here, with emphasis on generation of isolated attosecond pulses, the finite-domain time-difference method was used to analyze the funnel-waveguide with respect to the geometry-dependent plasmonic features such as the field enhancement factor, enhanced plasmonic field profile and hot-spot location. Then an extended semi-classical model of high-order harmonic generation was adopted to predict the EUV spectra generated from the funnel-waveguide in consideration of the spatial inhomogeneity of the plasmonic field within the hot-spot volume. Our simulation finally proved that isolated attosecond pulses can be produced at fast repetition rates directly from a few-cycle femtosecond laser or by synthesizing a two-color laser consisting of two multi-cycle pulses of cross-polarized configuration. (paper)

Molecular characterization of vancomycin-resistant Enterococcus faecium isolates from Bermuda.

Directory of Open Access Journals (Sweden)

Patrick Eberechi Akpaka

Full Text Available Molecular characteristics of vancomycin resistant enterococci isolates from Bermuda Island is currently unknown. This study was conducted to investigate phenotypic and genotypic characteristics of VRE isolates from Bermuda Island using the chromogenic agar, E-tests, polymerase chain reaction (PCR, pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST. Eighteen E. faecium isolates were completely analyzed and were all resistant to vancomycin, susceptible to linezolid and quinupristin/dalfopristin, positive for vanA and esp genes. The MLST analysis confirmed most isolates were of the sequence types linked to clonal complex 17 (CC17 that is widely associated with outbreaks in hospitals. Infection control measures, antibiotic stewardship, and surveillance activities will continue to be a priority in hospital on the Island.

Molecular epidemiology of Klebsiella pneumoniae K1 and K2 isolates in Japan.

Science.gov (United States)

Harada, Sohei; Ishii, Yoshikazu; Saga, Tomoo; Aoki, Kotaro; Tateda, Kazuhiro

2018-03-20

Although severe infections caused by hypervirulent Klebsiella pneumoniae isolates, such as K1 isolates belonging to sequence type (ST) 23, have been a significant problem in Asian countries, epidemiology of these isolates in Japan remains unclear. We performed a nationwide molecular epidemiological study of K. pneumoniae K1 and K2 isolates in Japan. Of the 259K. pneumoniae isolates collected, 14 and 16 isolates were identified as capsular genotypes K1 and K2, respectively. All K1 isolates were ST23 or its closely related clones and showed high genetic similarity by pulsed-field gel electrophoresis (PFGE) and the DiversiLab system (DL). K2 isolates, belonging to ST14, ST25, ST65, ST86, and ST110, were more genetically diverse than K1 isolates. Isolates belonging to a specific ST showed identical virulence gene profiles with a few exceptions. PFGE and DL results using K1 and K2 isolates were generally in agreement. Copyright © 2018. Published by Elsevier Inc.

Waste Isolation Pilot Plant: Geotechnical field data and analysis report, July 1986-June 1987: Volume 2

International Nuclear Information System (INIS)

1988-03-01

The Geotechnical Field Data and Analysis Report (GFDAR) is prepared to provide a timely assessment of the geotechnical status of the Waste Isolation Pilot Plant (WIPP). During the period of shaft sinking and construction of the principal underground access and experimental areas, reporting was on a quarterly basis. Because geotechnical responses of existing underground facilities have slowed to nearly steady-state and excavation of the waste storage panels will take place more slowly and over an extended period, reporting in the coming years will be on an annual cycle. Volume 2 constitutes the principal documentation and presentation of data and techniques used to acquire the data, the performance history of the instrumentation, and the complete set of data from each of the underground facilities. In addition, it presents the results of geologic logging, stratigraphic mapping, and mapping and evaluation of excavation-induced fractures. This volume has as its anticipated audience those Project personnel who need to perform data analyses beyond those provided in Volume 1, and external personnel who may choose to perform other analyses and evaluations for their own purposes. 2 refs., 368 figs., 27 tabs

Genetic diversity of human isolates of Salmonella enterica serovar Enteritidis in Malaysia.

Science.gov (United States)

Bakeri, S A; Yasin, R M; Koh, Y T; Puthucheary, S D; Thong, K L

2003-01-01

The study was undertaken to determine clonal relationship and genetic diversity of the human strains of Salmonella enterica serovar Enteritidis isolated from 1995 to 2002 from different parts of Malaysia. Antimicrobial susceptibility test, plasmid profiling and pulsed-field gel electrophoresis were applied to analyse 65 human isolates of S. Enteritidis obtained over an eight year period from different parts of Malaysia. Four nonhuman isolates were included for comparison. A total of 14 distinct XbaI-pulsed-field profiles (PFPs) were observed, although a single PFP X1 was predominant and this particular clone was found to be endemic in Malaysia. The incidence of drug resistant S. Enteritidis remained relatively low with only 37% of the strains analysed being resistant to one or more antimicrobial agents. All except one resistant strain carried at least one plasmid ranging in size from 3.7 to 62 MDa giving nine plasmid profiles. The three isolates from raw milk and one from well-water had similar PFPs to that of the human isolates. Salmonella Enteritidis strains were more diverse than was previously thought. Fourteen subtypes were noted although one predominant clone persisted in Malaysia. The combination of pulsed-field gel electrophoresis, plasmid profiling and antibiograms provided additional discrimination to the highly clonal strains of S. Enteritidis. This is the first report to assess the genotypes of the predominant clinical S. Enteritidis in different parts of the country. As S. Enteritidis is highly endemic in Malaysia, the data generated would be useful for tracing the source during outbreaks of gastroenteritis in the study area.

Development and characterization of a multi-layer magnetorheological elastomer isolator based on a Halbach array

Science.gov (United States)

Przybylski, Michal; Sun, Shuaishuai; Li, Weihua

2016-10-01

Most existing vibration isolators and dampers based on magnetorheological (MR) materials need electrical power to feed magnetic coils to stimulate the MR material, so if there is a loss of power, such as during a strong earthquake or system failure, they are unable to protect the structure. This paper outlines the design and test of a controllable multilayered magnetorheological elastomer (MRE) isolator based on a circular dipolar Halbach array; which is a set of magnets that generates a strong and uniform magnetic field. Combining an MRE layered isolator system with the Halbach array allows for constant vibration isolation with very low power consumption, where the power generated is only used to adjust the Halbach position. When this system was tested it successfully altered the lateral stiffness and damping force by 81.13% and 148.72%, respectively. This paper also includes an extended analysis of the magnetic field generated by the circular dipolar Halbach array and a discussion of the improvements that may potentially improve the range of magnetic fields generated.

An isolated vaginal metastasis from rectal cancer

Directory of Open Access Journals (Sweden)

Ai Sadatomo

2016-02-01

Conclusion: We should keep the vagina within the field of view of pelvic MRI, which is one of the preoperative diagnostic tools for colorectal cancer. If female patients show gynecological symptoms, gynecological examination should be recommended. Isolated vaginal metastases are an indication for surgical resection, and adjuvant chemotherapy is also recommended.

Biological Traits of Botrytis cinerea Pers. Isolates Differently Sensitive to Dicarboximides

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Brankica Tanović

2007-01-01

Full Text Available A study of biological characteristics of both field and laboratory isolates revealed that highly resistant isolates were morphologically different from their original wild types. The majority of them were less pathogenic and produced less sclerotia than the original ones.Significant negative correlation between osmotic sensitivity and the degree of resistance was recorded. The correlation between micelium growth rate and resistance to dicarboximides was also significant and negative. Growth medium, acidity and growth temperature had less effect on the micelium growth rate of the highly resistant isolates than on the sensitive ones.

Variation in resistance of natural isolates of Staphylococcus aureus to heat, pulsed electric field and ultrasound under pressure.