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Biomedical subjects

Y Becker

Publications and source records attributed to Y Becker.

At least 217 records · Page 12Linked to original sources
PubMed1972

Congocidine and distamycin A, antipoxvirus antibiotics.

The antibiotics congocidine and distamycin A inhibited the replication of Shope fibroma and vaccinia viruses in BSC(1) cells. Treatment of infected cultures with congocidine for a 12-hr period resulted in an irreversible inhibitory effect on virus development. A longer period of treatment with the antibiotic also resulted in inhibition of the residual infectious virions present in the treated cells. Distamycin A inhibited the replication of poxviruses, but its inhibitory effect was reversed when the antibiotic was removed from the infected cells even as long as 24 hr after treatment. The inhibitory effect of distamycin A and its reversibility resembled the antipoxvirus activity of rifampin.

Amidines↗
PubMed1972

Reverse transcriptase-containing particles induced in rous sarcoma virus-transformed rat cells by arginine deprivation.

Incubation of rat cells transformed by Rous sarcoma virus (RSV) in an arginine-deficient medium resulted in accumulation of particles in the culture medium. Such particles did not appear when the transformed rat cells were incubated in a complete medium nor in the medium of primary rat cells which were incubated either in arginine-deficient or complete media. The particles which were released from the arginine-deprived transformed rat cells resemble C-type particles in their properties. These particles band in sucrose gradients at a density of 1.16 g/ml and contain 35S ribonucleic acid (RNA) molecules and a reverse transcriptase activity. Analysis of the cytoplasm of transformed and primary rat cells, deprived and undeprived of arginine, revealed the presence of reverse transcriptase-containing particles which banded in sucrose gradients at a density of 1.14 g/ml. These particles differed from the particles released into the medium by the arginine-deprived RSV-transformed rat cells. The deoxyribonucleic acid (DNA) molecules synthesized in vitro by the reverse transcriptase present in the particles isolated from the medium of arginine-deprived cells hybridized to RSV RNA, whereas the DNA synthesized by the cell-bound enzyme had no homology to RSV RNA.

Animals↗
PubMed1971

Deoxyribonucleic acid-dependent ribonucleic acid polymerase activity in purified trachoma elementary bodies: effect of sodium chloride on ribonucleic acid transcription.

Highly purified trachoma elementary bodies (T'ang strain), incubated in the presence of the four nucleoside triphosphates [Mg(2+), Mn(2+), 2-mercaptoethanol, tris(hydroxymethyl)aminomethane buffer (pH 7.5)] were found to incorporate (3)H-uridine triphosphate (UTP) into ribonucleic acid (RNA) molecules. Eighty-seven per cent of the labeled molecules were sensitive to ribonuclease treatment. In vitro RNA synthesis was almost completely inhibited by actinomycin D. Rifampin was also inhibitory, but allowed some initial RNA synthesis before complete inhibition occurred. When the reaction mixture lacked Mn(2+), trachoma elementary bodies synthesized, for a limited period, high-molecular-weight RNA species (23 to 24S, 16 to 17S, and 10 to 11S). Addition of 0.2 m NaCl to the same reaction mixture stimulated and prolonged (3)H-UTP incorporation into the same radioactive RNA species. Addition of 0.001 m Mn(2+) instead of NaCl also stimulated (3)H-UTP incorporation but prevented the synthesis of the high-molecular-weight RNA species.

Amnion↗