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Biomedical subjects

E Katchalski

Publications and source records attributed to E Katchalski.

At least 19 recordsLinked to original sources
PubMed1974

Action of a basic copolymer of ornithine and leucine on cells of Staphylococcus aureus.

A basic, random copolymer of l-ornithine and l-leucine (OL; molar ratios 1:1) was bactericidal to a sensitive (S) strain of Staphylococcus aureus at low concentration. Resistant cells (R) were selected from the culture medium and, after serial transfers to solutions containing increasing amounts of the polymer, grew well in the presence of very high concentrations of it (1,000 mug/ml). S cells bound much more OL than did R cells, but no difference in binding was shown between separated cell walls or cell membranes of S and R. The binding of OL and sensitivity to it were not dependent on the teichoic acid-content of the cells. Bound OL was only partially removed from the cells by a variety of reagents, such as sodium dodecyl sulfate, Triton X-100, dilute trichloroacetic acid, and Ba(OH)(2), and the extent of removal was similar for R and S cells.

Cell Membrane↗
PubMed1973

Induction of lymphocyte transformation by sequential treatment with neuraminidase and galactose oxidase.

Treatment of mouse-spleen cells with galactose oxidase (EC 1.1.3.9) after incubation with neuraminidase (EC 3.2.1.18) induced extensive blastogenesis. Treatment of the cells with galactose oxidase before incubation with neuraminidase had very little stimulatory effect. Either of these enzymes alone had practically no effect on the cells. The lymphocyte transformation induced by galactose oxidase in neuraminidase-treated cells was decreased upon reacting the cells with borohydride or hydroxylamine, whereas treatment with these compounds did not affect transformation of cells by concanavalin A. It is suggested that galactosyl residues exposed by the action of neuraminidase on the cell membrane are oxidized by galactose oxidase, and the aldehyde moiety thus formed is involved in the induction of blastogenesis.

Alcohol Oxidoreductases↗
PubMed1973

Transformation of neuraminidase-treated lymphocytes by soybean agglutinin.

Transformation of mouse-spleen lymphocytes in the presence of soybean agglutinin is markedly enhanced after their treatment with neuraminidase (EC 3.2.1.18). Incubation of the cells with the enzyme also facilitates their agglutination by the lectin. The soybean agglutinin-induced agglutination and transformation is inhibited specifically by N-acetyl-D-galactosamine. New specific binding sites for soybean agglutinin were shown to appear after neuraminidase treatment. It is postulated that the transformation of neuraminidase-treated mouse-spleen lymphocytes induced by soybean agglutinin is caused by the binding of the lectin to galactosyl residues exposed by the action of neuraminidase on the cell membrane.

Animals↗
PubMed1972

Membrane site modified on induction of the transformation of lymphocytes by periodate.

Lymphocytes isolated from different sources undergo blastogenesis after mild treatment with periodate. Incubation of mouse spleen lymphocytes with neuraminidase or papain markedly reduces their response to periodate. Transformation induced by concanavalin A of the enzymically treated cells is not impaired. Blastogenesis induced by periodate is decreased when periodate-treated lymphocytes are reacted with borohydride, hydroxylamine, or semicarbazide. Treatment with these compounds does not affect transformation of cells by concanavalin A. It is suggested that different membrane sites are involved in lymphocyte transformation induced by periodate and by concanavalin A. The periodate target site seems to include a glycoprotein complex containing sialic acid that yields, on oxidation, an aldehyde moiety that is essential for transformation.

Animals↗