Search PubMed⌕ Search

Biomedical subjects

J Sakurai

Publications and source records attributed to J Sakurai.

161 records · Page 9Linked to original sources
PubMed1975

Characterization of the temperature-dependent inactivating factor of the thermostable direct hemolysin in Vibrio parahaemolyticus.

The termostable direct hemolysin of Vibrio parahaemolyticus is inactivated by heating at around 55 C with an inactivating factor isolated from culture filtrates of V. parahaemolyticus. The characteristics of the temperature-dependent inactivating factor were studied by using polyacrylamide gel disc electrophoresis. It was found that when heated with the hemolysin, the inactivating factor destroyed the hemolysin and thus inactivated the hemolytic activity, suggesting that the inactivating factor has proteolytic activity. It was also demonstrated that the inactivating factor itself is heat labile, losing its activity on heating with the hemolysin at 95 C for 15 min. The inactivating factor was stimulated by the presence of NaCl or MgCl2 and showed maximal activity at around pH 8.0. The results support our previous hypothesis that the Arrhenius effect observed with crude hemolysin of V. parahaemolyticus is due to the presence of a temperature-dependent inactivating factor. The fact that the factor is activated on heating at 50 to 60 C but is inactivated on heating at 70 to 100 C explains the Arrheius effect of crude hemolysin of V. parahaemolyticus.

Cell-Free System↗
PubMed1975

Interaction of thermostable direct hemolysin of Vibrio parahaemolyticus with human erythrocytes.

The interaction between thermostable direct hemolysin produced by Vibrio parahaemolyticus WP-1 and human erythrocytes was studied. The lysis of human erythrocytes by the hemolysin was dependent of temperature and no hemolysis occurred at low temperature (0-4 C), but the hemolysin was adsorbed on human erythrocytes even at low temperature. No hemolysis was observed when antihemolysin antiserum was mixed with the hemolysin and human erythrocytes at zero time. On the other hand, lysis of the cells by hemolysin was not completely inhibited when the antiserum was added during the lag time and the inhibitory effect decreased with delay in the time of addition of antiserum. The inhibitory effect of the antiserum decreased with increase in the incubation temperature, increase in the concentration of divalent cations, and decrease in pH. These results suggest that lysis of human erythrocytes by the hemolysin is at least a two-step process consisting of adsorption of the hemolysin to human erythrocytes and the step(s) following adsorption.

Adsorption↗
PubMed1974

Existence of two distinct hemolysins in Vibrio parahaemolyticus.

Two distinct hemolysins were demonstrated in Vibrio parahaemolyticus. A thermostable direct hemolysin purified from V. parahemolyticus WP-1, a Kanagawa phenomenon (KP)-positive strain, is antigenically different from a thermolabile hemolysin produced by V. parahaemolyticus T-3454, a KP-negative strain. The thermostable direct hemolysin was found in KP-positive strains but not in KP-negative strains. On the other hand, the thermolabile hemolysins were found in both KP-positive and -negative strains, although some KP-positive strains did not produce this hemolysin.

Animals↗
PubMed1973

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↗
PubMed1972

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↗
PubMedDate not supplied

Left ventricular hypertrophy due to aortic bypass grafting with a long prosthesis.

Progressive left ventricular hypertrophy was observed following operations in which long bypasses were inserted from the ascending aorta to the abdominal aorta for aneurysm exclusion in cases of thoracic aortic aneurysm. This effect was not observed after operations in which there was grafting with a short prosthesis for abdominal aortic aneurysm, wrapping and trans-section of the dissecing aneurysm. Clinical and experimental studies of the hemodynamic aspects suggest that the left ventricular hypertrophy was caused by an increase in systolic blood pressure at the aortic root due to the low distensibility of the long graft, a decrease in the Windkessel effect by exclusion of the proximal aorta and energy loss by turbulence formation of the proximal anastomotic area. Therefore, the distensibility or compliance at the long prosthesis seems to be very important in cases with long grafts of the aorta.

Animals↗