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Biomedical subjects

S Kudo

Publications and source records attributed to S Kudo.

At least 343 records · Page 19Linked to original sources
PubMed1981

Cell cycle-associated changes of guanylate cyclase activity in synchronized Tetrahymena: a possible involvement of calmodulin in its regulation.

Guanylate cyclase activity decreased during the division phase of heat-shock synchronized Tetrahymena pyriformis, strain GL. However, when Ca2+ was removed by EGTA to negate the effects of the Ca2+-binding protein (calmodulin), which is required for the full activity of guanylate cyclase in this organism, no significant change in the enzymatic activity was observed throughout the cell cycle. On the other hand, the reduced guanylate cyclase activity at division phase was associated with a decreased level of calmodulin content. These results suggest that fluctuations in guanylate cyclase activity during the cell cycle would be dependent on the concentration of calmodulin.

Animals↗
PubMed1981

Occurrence of bovine dermatophilosis in the southernmost islands of Japan.

Such cutaneous symptoms as characteristic incrustation and alopecia were noticed in 25 calves of the indigenous Japanese Black breed grazing on subtropical islands in Japan over a period of April, 1978 to February, 1980. These islands were Ishigaki, Kuro, Yonaguni and Tarama belonging to the Sakishima Islands. Microbiological and pathological examination on three of these calves revealed that the calves were affected with dermatophilosis caused by Dermatophilus congolensis. The disease in these calves seemed to be the same as that reported previously in other countries, since it attacked young calves in a humid district with an abundant rainfall. It broke out first on Ishigaki Island and subsequently on the other islands in 3 years. Discussion was made on factors inducing these outbreaks.

Actinomycetales↗
PubMed1980

Increase in oxytocin secretion at ejaculation in male.

In this study changes in plasma oxytocin levels were determined before and after ejaculation in patients with abnormal spermatogenesis. Plasma oxytocin levels rose significantly after ejaculation (P < 0.001, n = 17). There was no obvious correlation between plasma oxytocin levels and sperm count, sperm motility or the number of abnormal forms. Oxytocin may play a role in the precipitation of ejaculation in males.

Ejaculation↗
PubMed1980

Studies on cyclic nucleotide metabolism in Tetrahymena pyriformis: partial characterization of cyclic AMP- and cyclic GMP-dependent phosphodiesterases.

Cyclic nucleotide phosphodiesterase [EC 3.1.4.17] was examined in tetrahymena pyriformis strain NT-1. Enzymic activity was associated with the soluble and the particulate fractions, whereas most of the cyclic GMP phosphodiesterase activity was localized in the soluble fraction; the activities were optimal at pH 8.0-9.0. Although very low activities were detected in the absence of divalent cations, they were significantly increased by the addition of either Mg2+ or Mn2+. A kinetic analysis of the properties of the enzymes yielded 2 apparent K(m) values ranging in concentration from 0.5 to 50 micron and from 0.1 to 62 micron for cyclic AMP and GMP, respectively. A Ca2+ -dependent activating factor for cyclic nucleotide phosphodiesterase was extracted from Tetrahymena cells, but this factor did not stimulate guanylate cyclase [EC 4.6.1.2] activity in this organism. On the other hand, tetrahymena also contained a protein activator which stimulated guanylate cyclase in the presence of Ca2+, although this activator did not stimulate the phosphodiesterase. The results suggested that Tetrahymena might contain 2 types of Ca2+ -dependent activators, one specific for phosphodiesterase and the other for guanylate cyclase.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1979

Magnesium-sensitive guanylate cyclase and its endogenous activating factor in Tetrahymena pyriformis.

Guanylate cyclase [EC 4.6.1.2] activity in Tetrahymena pyriformis cells was associated with particulate fractions, but not with soluble fractions. Mg2+ was much more effective than Mn2+ in activating the cyclase activity. Both specific and total cyclase activities with Mg2+ in the particulate fraction were very much lower than those in the original homogenate. The addition of the soluble fraction resulted in a marked enhancement of the particulate-bound cyclase activity, while the adenylate cyclase [EC 4.6.1.1] activity was not enhanced. The enhancement was dependent on Ca2+, and the activating factor is suggested to be a protein.

Animals↗