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Biomedical subjects

A K Kleinschmidt

Publications and source records attributed to A K Kleinschmidt.

At least 37 records · Page 2Linked to original sources
PubMed1972

Characterization by electron microscopy of fused F-prime factors in Escherichia coli.

During previous attempts to find mutants in which incompatibility between two F-prime (F') factors of E. coli is abolished, we found that two F' factors harbored in the same cell occasionally recombined to form a single genetic unit. Thus, a fused F'trp(+)arg(+) factor was obtained from a mating of a strain carrying recA F'trp(+) with a strain carrying recA F'arg(+). In the present paper physical fusion of the two F' factors, inferred from genetic studies, is confirmed by electron microscopy. F DNA was extracted, after detergent lysis, from four fused F' strains: the parental F'trp(+) and F'arg(+) strains and three F(+) strains. This supercoiled DNA was separated on ethidium bromide-cesium chloride gradients and converted to the open circular from before electron microscopy. The contour lengths in mum of the various DNA preparations were: F'trp(+), 59.4; F'arg(+), 33.2; the four F'trp(+)arg(+) factors, 38.5, 39.6, 63.2, and 73.5: the three F factors, 31.1, 31.1, and 31.0. Thus, different fused F' factors formed from the same parental F' factors vary in length, but are shorter than the sum of the parental F' factors.

Centrifugation, Density Gradient↗
PubMed1969

Acetyl coenzyme A carboxylase: filamentous nature of the animal enzymes.

Acetyl coenzyme A carboxylases purified from several animal tissues exist as enzymatically active polymeric filaments of high molecular weight and have simillar electron microscopic, hydrodynamic, and catalytic properties. These filaments reversibly dissociate into inactive protomers of uniform size. Their re-assembly into catalytically active filaments is promoted by the presence of an allosteric activator.

Adipose Tissue↗