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Biomedical subjects

D C Swartzendruber

Publications and source records attributed to D C Swartzendruber.

46 records · Page 3Linked to original sources
PubMed1969

Alteration in bacterial morphology by optochin and quinine hydrochlorides.

Incubation of washed bacterial and ribosomal suspensions with optochin or quinine hydrochloride caused an increase in the turbidity of the suspensions and the appearance of electron-dense cytoplasmic aggregates in the treated cells. These effects were more pronounced with optochin hydrochloride than with quinine hydrochloride, and they did not correlate with the relative sensitivities of different bacteria to growth inhibition by optochin or quinine.

Bacillus subtilis↗
PubMed1966

Breakdown of DNA in x-irradiated Escherichia coli.

A comparison of differences in incorporation and loss of radio-activity between two strains of Escherichia coli shows that: (a) three times as much irradiation is necessary to produce the same reduction in incorporation of H(3)-thymidine in B/r, the resistant strain, as in B(s - 1), the sensitive one; (b) radioactivity is lost from the DNA of previously labeled bacteria during the first few cell generations after X-ray exposure, and even though the initial rate of loss is similar for all strains, the sensitive one loses much more label; (c) loss of DNA is a complicated function of dose. Losses increase with dose up to 25 or 50 kr in both strains; with higher doses, losses decrease in B(s - 1) but are unchanged in B/r. Since in both strains labeled RNA is retained in irradiated cells, lysis has not occurred but the DNA is broken down into small pieces which leak from each cell. Losses from either strain do not occur at ice-bath temperature, indicating that breakdown is a function of metabolic processes. A proposed mechanism for X-ray damage and repair is advanced.

DNA, Bacterial↗
PubMed1965

Electron microscopic autoradiography of germinal center cells in mouse spleen.

The fine structure of tritiated thymidine-labeled cells in antigen-stimulated mouse spleen germinal centers is described. In studies on the ultrastructural level, two labeled cell types found in germinal centers are observed. Large lymphocytes are characterized by their very numerous free ribosomes, a paucity of endoplasmic reticulum, relatively few mitochondria, and a poorly developed Golgi region. The nuclei are large and vesicular, and large nucleoli are present. A second labeled cell type appears to contain more mitochondria and has a higher development of the Golgi area. The nucleus contains large, numerous blocks of chromatin, indicative of a more differentiated cell type. Reticular cells, both phagocytic and non-phagocytic, were not observed to be labeled in the germinal centers.

Animals↗