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University of New Hampshire

Theses/Dissertations

1990

Biochemistry

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Initial Characterization Of Coagulin Polymerization And A Novel Trypsin Inhibitor From Limulus Polyphemus, Maribeth Ann Donovan Jan 1990

Initial Characterization Of Coagulin Polymerization And A Novel Trypsin Inhibitor From Limulus Polyphemus, Maribeth Ann Donovan

Doctoral Dissertations

In the final step of coagulation in the horseshoe crab, coagulogen (M$\sb{\rm w}$ = 19,000, from sedimentation equilibrium) is converted by discrete proteolysis into its clottable form, coagulin. Coagulogen does not have a strong tendency to self-associate. In 0.1 M ammonium bicarbonate, 50 mM Tris-HCL (pH 8.1), trypsin generated coagulin rapidly associates to form a stable, solid gel. Polymerization is pH-dependent, with reversible depolymerization occurring in acid (midpoint pH 5.4). Sedimentation velocity analysis reveals that stable intermediates remain at pH 2.5, with 30-31 s being the predominant form along with monomer (1.89 s) and larger forms ($>$60 s). Near …


Characterization Of A Cytotoxin From Campylobacter Jejuni And Its Role In Pathogenicity, Sangeeta Mahajan Jan 1990

Characterization Of A Cytotoxin From Campylobacter Jejuni And Its Role In Pathogenicity, Sangeeta Mahajan

Doctoral Dissertations

Campylobacter jejuni is a major cause worldwide of human gastroenteritis. In this study, the pathogenicity of the organism was examined in fertile hens' eggs and the mortality data and histopathological findings induced by both the organism and bacteria-free filtered broth were similar. The absence in chick embryo tissues of either bacteria or an inflammatory infiltrate suggested a toxic etiology. A protein was obtained from the filtrate by gel electroelution and this was sensitive to heat, pH changes and trypsin treatment and was lethal for the fertile hen's egg. It showed cytotoxic effects in primary chick embryo fibroblast (PCEF), Chinese hamster …