Clostridia toxin

Gas gangrene Clostridium perfringens Clostridia toxin Activates phosphohpase to break down cell membranes. (Major cause of death in First World War and American Civil War)... 

Biological Applications Measuring membrane potential detecting Clostridia toxin activity probes for Na, K-ATPase reaction mechanism examining activity of ion channels "... 

Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of Clostridia. Studies indicate that a toxin produced by Clostridium difficile is a primary cause of antibiotic-associated colitis. ... 

Shone CC, Tranter HS (1995) Growth of Clostridia and preparation of their neurotoxins. In Curr. Top. Microbiol. Immunol. 19 143-60 Shone CC, Quinn CP, Wait R, Hollis B, Fooks SG, Hamblen P (1993) Proteolytic cleavage of synthetic fragments of vesicle-associated membrane protein, isoform-2 by botulinum type B neurotoxin. In Eur. J. Biochem. 217 965-71 Simpson LL (ed)(1989) Botulinum neurotoxin and tetanus toxin. San Diego Academic Press... 

C. perfringens is the most important of the histotoxic clostridia that cause tissue infections in humans, especially of the muscle tissue (clostridial myonecrosis or gas gangrene). The organism is more aerotolerant than most other anerobes. In addition to toxins and enzymes, many of which have lethal, cell-destroying and hemolytic properties, a number of nonlethal enzymes are also produced and apparently contribute to the invasiveness of the organism in the tissue. These include collagenase, deoxyribonuclease, and hyaluronidase. 

All types of hotulinum toxin are sensitive to low pH such as that existing in the stomach as well as to pepsin, the protease produced in the stomach. However, the toxins produced by Clostridia are complexed with other proteins and the complexes are relatively resistant to digestion in the stomach. They dissociate at the more alkaline pH of the small intestine, where the dissociated toxin can be... 

Several species of Clostridia are able to produce botulinum toxins. These have been divided into groups with distinct physiological properties although a particular botulinum toxin type can be produced by more than one group. However, it has been found that botulinus toxin can be produced by C. botulinum strains which are clearly distinct from the hitherto defined species and are related to different species such as C. butyricum and C. baratii which have... 

The answer is 3 [IV B 5[. Horses and other species that depend heavily on cecal digestion (e.g., guinea pig, gerbil) appear to be more susceptible to the effects of oral antibiotics. Oral antibiotics can disturb the normal cecal or colonic flora and allow proliferation of toxin producers, such as clostridia. In horses, dosages of antibiotics such as tetracycline or lincomycin that are well-tolerated by other species can induce acute colic and diarrhea that may be fetal. 

Gastrointestinal colonization in adults or children by Clostridia bacteria does not t5qjically take place except in circumstances where the normal flora has been altered by antibiotic treatment (Cherington, 1998). Botulism results from in vivo production of toxin, analogous to the pathogenesis of infant botulism (Chia et al., 1986). Support for this form of botulism is provided by the demonstration of prolonged excretion of toxin and C. botulinum in stool, by the demonstration of C. botulinum spores but not preformed toxin in suspected foods, or both. 

Although Clostridia produce potent toxins, the pure collagenase is not very toxic (Mandl, 1961). However, administration of ma.ssive doses into tail veins of mice caused vascular damage and death resulted from pulmonary hemorrhage (Howes el al., 1960). 

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