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Biomedical subjects

T Miwatani

Publications and source records attributed to T Miwatani.

216 records · Page 12Linked to original sources

Purification and characterization of thermostable direct hemolysin of Vibrio parahaemolyticus.

A thermostable direct hemolysin was purified from culture filtrates of Vibrio parahaemolyticus. The purified hemolysin gave one precipitation line with the antihemolysin antiserum on agar-gel diffusion test and a single band on polyacrylamide gel electrophoresis. The hemolysin was not inactivated by heating at 70 to 100 C for 10 min. The hemolytic activity was not enhanced by the addition of lecithin. It was demonstrated that the hemolysin was a protein with a molecular weight of approximately 118,000. Amino acid analysis revealed that 43% of total amino acids were acidic amino acids, whereas 11% were basic amino acids.

Amino Acids↗

Effect of heat (Arrhenius effect) on crude hemolysin of Vibrio parahaemolyticus.

Crude hemolysins prepared from various strains of Vibrio parahaemolyticus, which give positive Kanagawa phenomenon, were partly inactivated by heating at 60 C, but not inactivated significantly by heating at 80 to 90 C. The similar phenomenon has been reported as the Arrhenius effect in staphylococcal alpha toxin.

Gastroenteritis↗

Purification and partial characterization of a hemagglutinating factor (HAF): a possible adhesive factor of the diffuse adherent of Escherichia coli (DAEC).

The mannose-resistant hemagglutinating factor (HAF) was extracted and purified from a diffuse adherent Escherichia coli (DAEC) strain belonging to the classic enteropathogenic E. coli (EPEC) serotype (0128). The molecular weight of HAF was estimated to be 18 KDa by SDS-PAGE and 66 KDa by Sephadex G100, suggesting that the native form of HAF consists of 3-4 monomeric HAF. Gold immunolabeling with specific HAF antiserum revealed that the HAF is not a rigid structure like fimbriae on the bacterial surface. The immunofluorescence test using purified HAF on HeLa cells, in addition to the fact that the HAF is distributed among serotypes of EPEC, suggests that HAF is a possible adhesive factor of DAEC strains.

Adhesins, Escherichia coli↗

Stopping of spontaneous beating of cultured mouse and rat myocardial cells by a toxin (thermostable direct hemolysin) from Vibrio parahaemolyticus.

Low concentrations of thermostable direct hemolysin from Vibrio parahaemolyticus stopped the spontaneous beating of cultured mouse and rat myocardial cells. These low concentrations depolarized the maximal diastolic potential and inhibited the generation of action potential of cultured myocardial cells. The toxin lost its activity when preincubated with ganglioside, GT1 or GM1. GT1 was more effective than GM1. High concentrations of the toxin caused morphological damage of cultured mouse and rat myocardial cells, but did not stop the beating, or cause morphological damage of cultured chick myocardial cells.

Animals↗

Increase in membrane conductance and positive inotropic action of hemolysin produced by Vibrio parahaemolyticus on rabbit myocardium.

The effects of purified thermostable direct hemolysin from the cultured filtrate of Vibrio parahaemolyticus on both S-A node cells and atrial cells were studied electrophysiologically. Hemolysin caused the membrane conductance to increase, thereby causing membrane depolarization. The major ion responsible for this depolarization was Na+, but other ions, such as K+ and Ca2+, also participated. Positive inotropic action of hemolysin was observed, and the Na-Ca exchange mechanism was enhanced after hemolysin treatment.

Action Potentials↗