Tadashi Yasuhara

Purification and characterization of neutrophil chemotactic factors of Streptococcus sanguis

Two neutrophil chemotactic factors were isolated from the culture filtrates of Streptococcus sanguis ATCC 10556 and were chemically characterized as N-terminal blocked peptides of low molecular weight. One of the factors consisted of proline, valine, methionine, isoleucine and leucine and the other of methionine, isoleucine, leucine and phenylalanine. In both factors, methionine was detected as the sole N-terminal amino acid, but the amino group was blocked. The removal of N-terminal methionine yielded several N-terminal amino acids, suggesting that S. sanguis produced several N-terminal blocked methionyl peptides, all of which could be chemotactically active.

Activities of novel polyhydroxylated cardiotonic steroids purified from nuchal glands of the snake, Rhabdophis tigrinus

Seven novel polyhydroxylated steroids were isolated from the nucho‐dorsal glands of the snake, Rhabdophis tigrinus. Biological activities of these steroids in inhibiting (Na+ + K+)ATPase and in producing positive inotropic action were examined in comparison with those of ouabain and gamabufotalin. Gamabufotalin was approximately 10 times more potent than ouabain in inhibiting (Na+ + K+)ATPase. Two compounds, compounds III and XIII, of the seven, produced nearly equipotent enzyme inhibitory activity to ouabain. The activity of the remaining five was relatively low among the compounds tested. All compounds exhibited more or less positive inotropic action in the papillary muscle preparations. The ranking order of the potency was: gamabufotalin > ouabain and compound IV > compound III and XIII > compound I, II, XII and XIV.

Cutaneous Reactions Caused by Experimental Exposure to Jellyfish, Carybdea rastonii

Dermatitis caused by contact with tentacles of jellyfish was studied on 25 volunteers. Two tentacles cut from a living jellyfish, Carybdea rastonii, were applied on each of the forearms and skin reactions were observed.

Parallel bioassay of physalaemin and hylambatin on smooth muscle preparations and blood pressure

Hylambatin, a novel tachykinin endecapeptide isolated from the skin of the African frog Hylambates maculatus, must be ascribed to the physalaemin subfamily. It differs structurally from all other known tachykinins mainly in having a methionine residue replacing the usual leucine residue at position 2 from the C―terminus. In parallel bioassay on a number of in―vitro and in―vivo test objects, hylambatin and physalaemin were nearly indistinguishable from each other, with few moderate quantitative differences.