PubMed Health⌕ Search

Biomedical subjects

S C Holt

Publications and source records attributed to S C Holt.

168 records · Page 10Linked to original sources
PubMed1967

Fine structure of Sarcina maxima and Sarcina ventriculi.

The fine structure of Sarcina maxima and S. ventriculi was studied by electron and phase-contrast microscopy. The two organisms differ mainly with respect to their cell surface. A thick cellulose layer present on the cell wall of S. ventriculi was not observed on the surface of S. maxima. Carbon replication indicated that the outer surface of S. ventriculi is rough in contour, probably as the result of the fibrillar nature of the accumulated cellulose. The cytoplasm of both sarcinae contains inclusions similar to polysaccharide and polymetaphosphate granules. Mesosomes were observed in cells of S. maxima. Packets of S. ventriculi generally comprise a larger number of cells and are more irregularly constructed than those of S. maxima. Cells in large packets of S. ventriculi assume flattened or otherwise irregular shapes, whereas cells of S. maxima maintain a more uniform appearance.

Microscopy, Electron↗
PubMed1966

Photosynthetic Apparatus in the Green Bacterium Chloropseudomonas ethylicum.

Holt, Stanley C. (Dartmouth Medical School, Hanover, N.H.), S. F. Conti, and R. C. Fuller. Photosynthetic apparatus in the green bacterium Chloro-pseudomonas ethylicum. J. Bacteriol. 91:311-323. 1966.-When cells of Chloro-pseudomonas ethylicum were broken by ballistic disruption and examined by electron microscopy, vesicles 1,300 to 1,500 A long and 300 to 500 A wide were found to rim the periphery of the cell. Examination of these vesicles obtained by disruption with a French pressure cell and purified by density gradient centrifugation revealed inter-connections between the vesicles. During sonic and Mickle disruption of the cells, chlorophyll was released at a lower rate than soluble cytoplasmic components, but faster than the membrane-bound enzyme succinic dehydrogenase. Unlike the situation that exists in the purple photosynthetic bacteria, it appears that the chlorophyll in the green bacteria is contained as part of a structure which may be differentiated both structurally and functionally from the bacterial cytoplasmic membrane.

Journal Article↗
PubMed1966

Effect of light intensity on the formation of the photochemical apparatus in the green bacterium Chloropseudomonas ethylicum.

Holt, Stanley C. (Dartmouth Medical School, Hanover, N.H.), S. F. Conti, and R. C. Fuller. Effect of light intensity on the formation of the photochemical apparatus in the green bacterium Chloropseudomonas ethylicum. J. Bacteriol. 91:349-355. 1966.-When the green bacterium Chloropseudomonas ethylicum was grown at various light intensities, the formation of the photosynthetic vesicles was found to be an inverse function of the light intensity at which the cells were grown. The specific chlorophyll content of isolated vesicles varied as the light intensity was changed over a wide range. Thus, the regulation of chlorophyll content in C. ethylicum in response to a change in light intensity is achieved both by a change in the number of vesicles that are formed and by a change in the specific chlorophyll content of these vesicles.

Bacteria↗