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Biomedical subjects

M Oishi

Publications and source records attributed to M Oishi.

At least 325 records · Page 18Linked to original sources

Genetic transformation in Escherichia coli K12.

An auxotrophic strain of E. coli K12 treated with CaCl(2) was transformed for several markers at a frequency of up to 10(-6) per recipient cell by a DNA preparation isolated from a prototrophic strain. The transforming activity of the DNA preparation was eliminated by treatment with DNase, heat, or sonication, whereas RNase or Pronase treatment had little effect. Two closely linked genetic markers (leu and ara) showed a high degree of cotransformation linkage when high molecular weight DNA was used, but the linkage was almost completely eliminated when sheared, smaller molecular weight DNA was used. There is genetic evidence that the transformation is a result of the replacement of the preexisting genetic marker on the chromosome by that of the donor DNA.

Animals↗

Adenosine triphosphatase associated with adenosine triphosphate-dependent deoxyribonuclease (recB-recC enzyme-E. coli-ATP to phosphodiester hydrolysis ratio-DNA-dependent ATPase activity).

An ATPase activity that is completely dependent on DNA is associated with the ATP-dependent DNase (recB-recC enzyme) purified from Escherichia coli. There is a strong correlation between the ATPase and the DNase activities under various assay conditions. With E. coli DNA as substrate, 8-9 molecules of ATP are hydrolyzed to ADP and inorganic phosphate for every phosphodiester bond hydrolyzed by the DNase. The possible functional relationship of the ATPase and DNase activities is discussed.

Acrylamides↗