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Biomedical subjects

J Hatzfeld

Publications and source records attributed to J Hatzfeld.

45 records · Page 3Linked to original sources
PubMed1978

Methionine metabolism in BHK cells: preliminary characterization of the physiological effects of cycloleucine, an inhibitor of s-adenosylmethionine biosynthesis.

Cycloleucine is in vitro a competitive inhibitor of methionine adenosyltransferase, an enzyme involved in S-adenosylmethionine biosynthesis. The physiological effects of this drug on baby hamster kidney cells have been studied. When cells are grown in a medium containing 10 micron methionine, cycloleucine is an inhibitor of cell proliferation; high concentrations of methionine are able to withdraw this inhibition suggesting that cycloleucine toxicity is related to methionine metabolism. The drug does not primarily affect methionine uptake and its subsequent use for protein biosynthesis. Cycloleucine toxicity is correlated with a block of SAM biosynthesis and nucleic acids methylations. The actions of cycloleucine on progression in the cell cycle and DNA, RNA and protein biosynthesis are studied. The implications of these results are discussed.

Amino Acids↗
PubMed1975

Temperature-sensitive cell cycle mutants: a chinese hamster cell line with a reversible block in cytokinesis.

A thermosensitive line (TS 111) was isolated from a suspension culture of Chinese hamster fibroblasts, using a BUdR suicide selection technique. In this line, cytokinesis is blocked at 39 degrees C. DNA and protein synthesis are not arrested but keep on at a steady rate. Giant cells are produced which accumulate either numerous nuclei or one big nucleus with several nucleoli and more than a hundred chromosomes. At each nuclear cycle, all the chromosomes in the cell appear to condense in a synchronous manner, although it is possible that not all the sets of chromosomes duplicate. When the culture is returned to the permissive temperature (34 degrees C) after a prolonged arrest at the restrictive temperature, cytokinesis resumes with early extrusion of karyoplasts from multinucleated cells. The division block is independent of cell density in suspension culture and is not prevented by cell contact when cells grow attached to Petri dishes. At 34 degrees C, a residual expression of the mutation is indicated by the presence of binucleate and up to 30% anucleate cells. A remarkable similarity and some synergism exists between the mutation and cytochalasin B effects.

Animals↗
PubMedDate not supplied

[C3 stimulates the proliferation of human pre-B Raji cells].

In a defined medium in which transferrin (3 micrograms/ml) was the only source of exogenous proteins, Raji cells of the human pre-B lymphoblastoid cell line died within 48 h after forming polykaryons. The simple addition of purified C3 at a concentration equal to or higher than 3 micrograms/ml allowed Raji cells to divide. This preliminary report provides a defined system for studying the mitogenic effect of human C3 or C3 fragments upon proliferation of human B-cells lines.

B-Lymphocytes↗