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At least 19 recordsLinked to original sources
PubMed2026

A 29-plex MOL-PCR assay for simultaneous detection of selected major, non-typing, and accessory virulence genes in Clostridium perfringens.

Clostridium perfringens is an important pathogen of humans and animals, responsible for a broad spectrum of diseases mediated by diverse toxins and virulence factors. Precise and extended toxin-gene profiling is valuable for strain characterization and molecular epidemiological surveillance. Here, we describe the development of a 29-plex Multiple Oligonucleotide Ligation PCR (MOL-PCR) assay that enables the simultaneous detection of a large and important panel of 27 C. perfringens toxin-related genes - covering major typing toxins as well as an extended panel of non-typing and accessory virulence genes - thus moving beyond the classical toxinotyping framework. The assay was evaluated in comparison with six multiplex qPCR assays. In both systems, the gene encoding the Clostridium perfringens-specific serine O-acetyltransferase (EpsC) was used as a molecular marker for species confirmation, and an internal amplification control was included to detect potentially false-negative results. Analytical specificity testing confirmed exclusive amplification in C. perfringens and sequencing confirmed the toxin-gene profiles of reference strains. Comparative analysis of 72 reference and field isolates (1,944 data points) demonstrated complete concordance for 637 positive detections, yielding 100% positive agreement and 99.7% negative agreement relative to the comparative qPCR method. The limit of detection was 100 fg/µl (approx. 3 × 101 genome equivalents; GE) for qPCR and 1  pg/µl (approx. 3 × 102 GE) for MOL-PCR. Despite its high multiplex level, MOL-PCR showed high agreement with qPCR. The developed MOL-PCR method provides a rapid, high-throughput, and cost-effective tool for expanded toxin-gene profiling of C. perfringens isolates targeting major typing toxins and selected non-typing and accessory virulence genes. Therefore, it may support advanced toxin-gene characterization, molecular epidemiology, and One Health-oriented surveillance of evolving virulence landscapes.

Clostridium perfringens↗
PubMed1979

Characterization of the autolytic enzymes of Clostridium perfringens.

Clostridium perfringens and isolated walls of this organism autolysed rapidly when incubated in buffer at pH 7.0 with the release of free-reducing groups but no N-terminal amino acids. The predominant autolytic enzyme was an endo-beta-N-acetylglucosaminidase, and an endo-beta-N-acetylmuramidase was also present. The autolytic enzymes could be solubilized by extraction of the organisms with 5 M-LiCl and would then subsequently bind to and rapidly lyse walls of Micrococcus luteus and, more slowly, formamide-extracted walls of C. perfringens and walls of Bacillus subtilis. Lysis of C. perfringens walls by these extracted enzymes could not be demonstrated.

Acetylglucosaminidase↗
PubMedDate not supplied

Virulence factors of Clostridium perfringens.

Clostridium perfringens produces a variety of virulence factors. The mechanism of action of these factors usually falls into one of three groups. Some of these virulence factors, such as the alpha toxin, which is phospholipase C, and the kappa toxin, which is a collagenase, are enzymes that hydrolyze substances essential to the integrity of membranes or other body structures. Other virulence factors, such as the beta, episolon, and iota toxins, act primarily on the vascular endothelium, causing increased capillary permeability, especially in the brain. Still others, such as the delta and theta toxins, are essentially hemolysins. Theta toxin is similar in action and serologically related to streptolysin O.

Bacterial Toxins↗
PubMed1978

Effect of zinc and calcium ions on the production of alpha-toxin and proteases by Clostridium perfringens.

Clostridium perfringens produced at least three distinct proteases in a synthetic medium containing calcium. Two of them, thiol and ethylenediaminetetraacetic acid disodium salt-sensitive proteases, appeared at an early stage of growth, but the other one, perhaps being identical to the one produced in a calcium-deficient medium, appeared at a late stage. The production of these proteases depended on Ca2+ but not on Zn2+ in the medium. Alpha-toxin, perhaps being a zinc-containing metalloenzyme, was rather resistant to the proteases, but toxin, produced in a zinc-deficient medium or deprived of zinc with ethylenediaminetetraacetic acid disodium salt, was very sensitive. By adding Zn2+, the toxin lacking zinc may have been converted to the zinc-containing metalloprotein that is resistant to proteases. This may explain why alpha-toxin activity increased progressively in a zinc-containing medium in spite of simultaneous production of potent proteases and why it disappeared rapidly in a zinc-deficient medium.

Bacterial Toxins↗
PubMed1975

Purification and characterization of neuraminidase from Clostridium perfringens.

Clostridium perfringens cells were cultivated on a large scale using an automatic system. Neuraminidase secreted by the cells into the culture medium was purified 380 000-fold by: precipitation with ammonium sulfate between 50 and 85% saturation, filtration on Sephadex G-75, electrophoresis on polyacrylamide gel, and by isoelectric focusing. Three enzyme fractions with different migration rates were obtained by preparative disc electrophoresis in polyacrylamide gel, and five fractions with isoelectric points between pH 4.7 and 5.4 were observed after isoelectric focusing. This microheterogeneity disappeared after denaturation of the enzyme in 0.1% sodium dodecylsulfate or 8M urea. The isoelectric point of the denatured enzyme corresponded to pH 4.3. All enzyme fractions were identical with regard to their immunological and kinetic properties; they had the same molecular weights. The origin of the different "conformers" of neuraminidase is discussed. The existence of genuine isoenzymes could largely be excluded. The yield of neuraminidase was 65%, which corresponded to about 10 mg of pure enzyme from 100 l of culture medium. The enzyme was free of protease and various other glycosidase activities. The neuraminidase preparation appeared not to be contaminated by other proteins as judged by electrophoretic analysis using either the native enzyme or the enzyme denatured by sodium dodecylsulfate or urea; ultracentrifugation; chromatography on Sephadex G-200; and immunological methods. The molecular weights of the native or denatured enzyme were found to be in the range between 60 000 and 69 000 (on an average 63 750) using four independent methods. The existence of subunits of neuraminidase was excluded. The neuraminidase exhibited a spec. act. of 580 or 615 U/mg protein with glycopeptides from edible birds' nests or sialyllactose, respectively, as substrates. Additional kinetic properties and the UV-absorption spectrum of the enzyme are described.

Clostridium perfringens↗
PubMed1976

Purification and characterization of N-acetylneuraminate lyase from Clostridium perfringens.

Clostridium perfringens cells were cultivated on a large scale using an automatic system. 2) N-Acetylneuraminate lyase, which is a cytosolic enzyme, was liberated from the bacteria by cell lysis using lysozyme in hypotonic solution. The enzyme was purified 770-fold by precepitation with ammonium sulfate, filtration on Sephadex A-50 and final preparative electrophoresis in a 7.5% polyacrylamide gel. Yield: 12 mg from 1 kg wet cell paste; specific activity: 167 nkat/mg protein. 3) The enzyme preparation appeared homogeneous in analytical disc electrophoresis, in gel electrophroesis in 0.1% sodium dodecylsulfate or 8m urea and in immunoelectrophoresis. Contaminating enzyme activities were not detected. 4) The isoelectric point of pH 4.7 was found for the enzyme. At 278 nm a molar extinction coefficient of 6.4 x 10(4)M-1 Xcm-1 was determined. The enzyme exhibited a Km value for N-acetylneuraminic acid of 2.8mM at its pH optimum of pH 7.2. The pH dependence of the Km value gives evidence that an ionizing guoup in the active center of the enzyme with a pKe value of 6.4 may be involved in the catalytic reaction. Pyruvate inhibited the cleavage reaction of N-acetylneuraminic acid competitively; Ki = 2.9mM. 5) An average molecular weight of 99200 was determined for the native enzyme using different methods. After denaturation in sokium dodecylsulfate or urea, a mean molecular weight of only 50000 could be demonstrated, indicating the existence of two enzyme subunits. The lyase molecule was shown by electron microscopy, using a negative staining technique, to consist of two hemispherical parts. 6) Two active sites per native enzyme molecule, probably corresponding to one active site per subunit, were found by incubation of the enzyme with radioactive pyruvate followed by borohydride reduction. The results obtained from chemical modification of the lyase with 5-diazonium-1H-tetrazole and iodocaetamide under various conditionsare interpreted as evidence for the presence of two reactive histidine residues in the enzyme molecule. It is probable that one residue per subunit forms the nucleophilic group participating in enzyme catalysis. A model suggesting the mechanism of reversible cleavage of N-acylneuraminic acids by the lyase is presented.

Binding Sites↗
PubMed1978

[Necrotizing enteritis in suckling pigs (Clostridium perfringens type C enterotoxemia). II. Toxin formation, heat and drug resistance of Clostridium perfringens strains isolated from suckling pigs and broilers with necrotizing enteritis].

Nineteen Clostridium perfringens Type C strains and ten foreign control strains of subtypes C1, C3, and C4 were tested for their toxin formation and spore resistance to heat. The 19 Type C strains had been isolated from unweaned piglets in the context of necrotising enteritis outbreaks in the GDR. The Clostridium perfringens Type C strains formed beta-toxin, but they failed to form epsilon-toxin or gamma-toxin, alpha-toxin was successfully recorded from 15 of the 19 strains tested from unweaned piglets. The minor-lethal toxin fractions were also tested, with delta-toxin being recorded from all strains, non-alpha-delta-theta-toxin from six, theta-toxin from five, and K-toxin from one. Tests for delta-toxin, lambda-toxin, and mu-toxin were negative. The Clostridium perfringens Type C strains isolated in the GDR from unweaned piglets with necrotising enteritis were, basically, identical with those described in Denmark by von Hogh (1967) with regard to toxin formation. Clostridium perfringens strains cultured in broilers with necrotising enteritis were characterised by regular toxin production in the context of alpha, theta, delta as well as non-alpha-delta-theta. They failed to form beta, epsilon, gamma and lambda, while mu-toxin was formed by them quite irregularly. They, consequently, are Type A strains. Resistance to chloramphenicol and/or oxytetracycline was exhibited by 78.5 per cent of 237 tested Clostridium perfringens strains which had been isolated from unweaned piglets and broilers with necrotosing enteritis. Multiple resistance was recorded from 33.9 per cent. All strains were susceptible to penicillin, nitrofurantoin, and erythromycin.

Animals↗
PubMed1979

Fluid accumulation in mouse ligated intestine inoculated with Clostridium perfringens enterotoxin.

Clostridium perfringens enterotoxin, when inoculated into the ligated intestinal loop of mice, caused marked distension due to fluid accumulation. The increase in weight of the intestinal loop was proportional to the log dose of enterotoxin within a range from 1 to 16 micrograms. The fluid accumulation was arrested by washing the loop with saline or by injection of the specific anti-enterotoxin serum into the loop 5 or even 30 min after inoculation of the enterotoxin. A significant increase in weight of the loop was found as early as 10 min after inoculation of the toxin. These results may suggest that entergotoxin is neither bound firmly to the mucosal membrane nor permeates into the cells of the intestinal wall. The mouse intestinal loop test is economical, simple to perform, and applicable for quantitative determination of the enteropathogenic activity of C. perfringens enterotoxin.

Animals↗
PubMed1975

Radiation resistance of spores of some Clostridium perfringens strains.

Clostridium perfringens spores (eight strains) were irradiated in a model system with 60Co gamma rays at -30 C. The quantal response data obtained were analyzed with extreme value statistics. It was found (at the 95% confidence level) that all eight strains followed the same rate of death and that this rate was probably (at the 95% level) not exponential. The statistics did not exclude, however, a normal, lognormal, Weibull, or related rate of spore kill. A more definitive study would be required to distinguish between the latter distributions.

Clostridium perfringens↗
PubMed1978

Efficacy of laboratory tests for the detection of enterotoxigenic Clostridium perfringens.

Nineteen Clostridium perfringens strains with positive erythemal and ligated intestinal loop reactions, and 22 strains with negative reactions, originating from food-poisoning cases, were tested comparatively using the fluorescent antibody (FA), reversed passive hemagglutination (RPHA), and immunodiffusion (ID) tests. All the biologically positive strains were detected by the three immunological tests used. The FA test detected five additional strains among the biologically negative group which did not react in RPHA or ID tests. Sporulating culture supernatant fluids, after 13 to 17h of growth, were satisfactory for testing for the presence of enterotoxin by the RPHA and ID tests. The FA test was used on cell smears.

Botulinum Toxins↗
PubMed1976

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

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.

Benzalkonium Compounds↗
PubMed1976

3alpha-, 7alpha- and 12alpha-hydroxysteroid dehydrogenase activities from Clostridium perfringens.

25 strains of Clostridium perfringens were screened for hydroxysteroid dehydrogenase activity; 19 contained NADP-dependent 3alpha-hydroxysteroid dehydrogenase and eight contained NAD-dependent 12alpha-hydroxysteroid dehydrogenase active against conjugated and unconjugated bile salts. All strains containing 12alpha-hydroxysteroid dehydrogenase also contained 3alpha-hydroxysteroid dehydrogenase although 12alpha-hydroxysteroid dehydrogenase was invariably in lesser quantity than the 3alpha-hydroxysteroid dehydrogenase. In addition, 7alpha-hydroxysteroid dehydrogenase activity was evident only when 3alpha, 7alpha, 12alpha-trihydroxy-5beta-cholanoate was substrate but notably absent when 3alpha, 7alpha-dihydroxy-5beta-cholanoate was substrate. The oxidation product 12alpha-hydroxy-3, 7-diketo-5beta-cholanoate is rapidly further degraded to an unknown compound devoid of either 3alpha- or 7alpha-OH groups. Group specificity of these enzymes was confirmed by thin-layer chromatography studies of the oxidation products. These enzyme systems appear to be constitutive rather than inducible. In contrast to C. perfringens. Clostridium paraputrificum (five strains tested) contained no measurable hydroxysteroid dehydrogenase activity. pH studies of the C. perfringens enzymes revealed a sharp pH optimum at pH 11.3 and 10.5 for the 3alpha-OH- and 12alpha-OH-oriented activities, respectively. Kinetic studies gave Km estimates of approx. 5 X 10(-5) and 8 X 10(-4) M with 3alpha, 7a-dihydroxy-5beta-cholanoate and 3alpha, 12alpha-dihydroxy-5beta-cholanoate as substrates for two respective enzymes. 3alpha-hydroxysteroid dehydrogenase was active against 3alpha-OH-containing steroids such as androsterone regardless of the sterochemistry of the 5H (Both A/B cis and A/B trans steroides were substrates). There was no activity against 3beta-OH-containing steroids. The 3alpha- and 12alpha-hydroxysteroid dehydrogenase activities, although differing in cofactor requirements cannot be distinguished by their appearance in the growth curve, their mobility on disc gel electrophoresis, elution volume on passage through Sephadex G-200 or heat inactivation studies.

Androsterone↗