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dc.contributor.authorJefferson, Kimberly Kayen_US

Clostridium difficile is a common cause of antibiotic-associated diarrhea and occasionally causes the life-threatening disease pseudomembranous colitis. The pathogenicity of the organism has been attributed to the production of two large exotoxins, toxin A (308,000 daltons) and toxin B (269,000 daltons). Toxin A is a powerful enterotoxin and is generally thought to play the more important role in the pathology of the disease. Toxin B may exert its effect after the initial tissue damage by toxin A. Both toxins cause rounding of mammalian culture cells by disrupting the cytoskeletal system. The similar biological activities and high percentage of sequence homology between the two toxins suggest that they have a similar mechanism of action. I found that purified preparations of both toxins cleave skeletal muscle actin at a single site, producing a 38,000 dalton actin fragment, and that the toxins are capable of autodigestion. The proteolytic activity may be involved in the mechanism of action of the toxins. I also analyzed an aberrant strain of C. difficile which reportedly lacked the gene for toxin B. Such a strain would be very useful for the study of the mechanism of toxin A. I concluded however, that the strain contained the genes for both toxin A and toxin B. The toxin genes and resulting proteins appear, however, to be slightly different from those of other strains.

dc.publisherVirginia Techen_US
dc.subjectpseudomembranous colitisen_US
dc.subject.lccLD5655.V855 1995.J444en_US
dc.titleClostridium difficile toxins A and B: exploring the possible mechanism of actionen_US
dc.contributor.departmentBiochemistry and Anaerobic Microbiologyen_US
dc.description.degreeMaster of Scienceen_US of Scienceen_US Polytechnic Institute and State Universityen_US and Anaerobic Microbiologyen_US
dc.contributor.committeechairWilkins, Tracy D.en_US
dc.contributor.committeememberGregory, Eugene M.en_US
dc.contributor.committeememberHackney, Cameron Rajen_US

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