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Biomedical subjects

K Sobue

Publications and source records attributed to K Sobue.

At least 145 records · Page 8Linked to original sources
PubMed1981

Ca2+-dependent modulator proteins from Tetrahymena pyriformis, sea anemone, and scallop and guanylate cyclase activation.

Previously, the guanylate cyclase activity of Tetrahymena pyriformis was shown to be activated by an endogenous modulator (calmodulin)-like protein (Na-gao, S., Suzuki, Y., Watanabe, Y., and Nozawa, Y. (1979) Biochem. Biophys. Res. Commun. 90, 261-268). This protein has now been identified as the modulator protein. The identification was based on the capability of this protein to activate the brain modulator-deficient phosphodiesterase and the mobility of this protein upon polyacrylamide gel electrophoresis. The activation of guanylate cyclase was specifically attributable to the Tetrahymena modulator protein since other modulator proteins examined (bovine brain, sea anemone, and scallop) were ineffective. Under the conditions where the activation of Tetrahymena guanylate cyclase occurred, guanylate cyclase activities from other sources, that include rat brain, rat lung, and human platelet, were not affected. In the phosphodiesterase activation, the potencies of scallop and Tetrahymena modulator proteins, which are represented by reciprocals of the quantities of proteins required for half-maximal activation of enzyme, were 66% and 55%, respectively, of that of the brain protein. The same decreasing order was seen for the affinity of these proteins for Ca2+ in enzyme activation. The results suggest a directional change of the modulator protein during the molecular evolution toward an increase in the capability in Ca2+-dependent enzyme activation.

Animals↗
PubMed1981

Purification of a calmodulin-binding protein from chicken gizzard that interacts with F-actin.

A calmodulin-binding protein called "caldesmon" was purified from chicken gizzard muscle as the major calmodulin-binding protein in this tissue. Its molecular weight estimated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis was 150,000, and two of these polypeptides constituted the native molecule. Caldesmon is an actin-binding protein also, binding F-actin reversibly in the presence or absence of Ca2+. The interaction of caldesmon with F-actin was abolished by the binding of calmodulin with the caldesmon. Because the interaction between caldesmon and calmodulin was Ca2+-dependent but the interaction between caldesmon and F-actin was not, Ca2+ acts as a flip-flop switch between the formations of two complexes, caldesmon.calmodulin and caldesmon.F-actin: increasing the formation of the former complex at increased Ca2+ level and the formation of the latter complex at decreased Ca2+ level. The equilibrium of the formations of both complexes was achieved at a Ca2+ concentration near 1 microM.

Actins↗
PubMed1981

Subcellular distribution of calmodulin and calmodulin-binding sites in Tetrahymena pyriformis.

The subcellular distribution of calmodulin and particulate calmodulin-binding activity was studied in a eukaryotic protozoan, Tetrahymena pyriformis NT-1. The particulate calmodulin-binding activity was found to be localized principally in microsomes and to some extent in cilia and surface membranes called pellicles. Nearly all (93%) of the total amount of calmodulin was recovered in two soluble compartments, the ciliary and postmicrosomal supernatant fractions.

Animals↗
PubMed1978

Concentrations of polyamines in renal cell carcinoma.

In order to obtain biochemical indicators for histopathological, biological and clinical malignancy of renal cell carcinoma (RCC), concentrations of protein, RNA, DNA and polyamines in 14 samples of RCC were measured and examined on their histopathological properties and clinical malignancies. The concentration of spermidine in RCC was significantly higher than that in normal renal tissue and a statistically significant difference was not detected between the concentrations of the other compounds in RCC and normal tissue. The concentration of spermidine and the ratio of spermidine/spermine were found to increase in the order of normal tissue, the well-differentiated type and the poorly-differentiated type of RCC while no significant difference was detected between the concentrations of the other compounds in these types. There was no difference in the concentrations of the compounds examined among the non-metastasis and istant-metastasis groups of RCC.

Adenocarcinoma↗
PubMed1977

Experimental carcinoma of the biliary tract induced in dogs by N-ethyl-N'-nitro-N-nitrosoguanidine.

The present study was designed to produce the experimental carcinoma of the biliary tract in dogs. Tube cholecystostomy was constructed in 8 mongrel dogs and 5-10 ml of 0.7-1.0 mg/ml solution of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) was administered through the tube every day for the maximum period of 180 days. As the results: The experiment had to be cut off in 7 dogs (5 dogs: The tube was inadvertently pulled out. 2 dogs: died of general weakness). Pathological changes were observed in one dog given ENNG for 180 days and sacrificed at 372 days after the beginning of the experiment. Macroscopically, scattered foci of flat elevation of the mucosa were observed in the entire mucosal surface of common bile duct and a tiny polypoid lesion at the terminal protion. A tiny polypoid projection was adenocarcinoma confined to the mucosa, and areas of flat elevation showed marked hyperplasia of mucosa with partial atypical proliferation. No remarkable findings were noted in other organs.

Adenocarcinoma↗