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S H BLACK

Publications and source records attributed to S H BLACK.

8 recordsLinked to original sources
PubMed1962

Permeability of bacterial spores. III. Permeation relative to germination.

Black, S. H. (The University of Michigan, Ann Arbor) and Philipp Gerhardt. Permeability of bacterial spores. III. Permeation relative to germination. J. Bacteriol. 83:301-308. 1962.-The passive diffusion of solutes into dormant spores, characterized previously with the test organism Bacillus cereus strain terminalis, has now been examined in relation to germination. Dormant spores did not take up specific germinants differently than they did other compounds, under conditions optimal for germination. Germinated spores, viable but prevented from growing out, displayed some changes in permeability, evidenced by increased total uptake of glucose and water and by observable penetration of a fluorescigenic dye. Heat-killed spores were as permeable to glucose and the dye as germinated ones.

Bacillus cereus↗
PubMed1962

Permeability of bacterial spores. IV. Water content, uptake, and distribution.

Black, S. H. (The University of Michigan, Ann Arbor) and Philipp Gerhardt. Permeability of bacterial spores. IV. Water content, uptake, and distribution. J. Bacteriol. 83:960-967. 1962.-Dormant and germinated spores of Bacillus cereus strain terminalis were examined for water properties. Respectively, they exhibited a mean density of 1.28 and 1.11 g/ml, a water content of 64.8 and 73.0%, and a total water uptake of 66.6 and 75.6%, based on spore weight, or 86.0 and 83.9%, based on spore volume. The results confirmed a previous report that internal and external water are in virtually complete equilibrium, but refuted a prevailing hypothesis that heat resistance is attributable to a dry core. A model of spore ultrastructure that evolved from the cumulative results pictures a moist, dense, heteroporous core. A new hypothesis is formulated as an explanation for thermostability in spores and possibly in other instances; it postulates the occurrence of an insolubly gelled core with cross-linking between macromolecules through stable but reversible bonds so as to form a high-polymer matrix with entrapped free water.

Bacillus↗
PubMed1961

Permeability of bacterial spores. I. Characterization of glucose uptake.

Black, S. H. (The University of Michigan, Ann Arbor) and Philipp Gerhardt. Permeability of bacterial spores. I. Characterization of glucose uptake. J. Bacteriol. 82:743-749. 1961.-The total uptake of glucose by masses of clean, dormant spores was measured to assess their permeability. After correction for intercellular space, packed spores of Bacillus cereus strain terminalis were found in 87 determinations to be permeated by glucose to 40% of their weight. The glucose uptake was relatively independent of environmental variables, and thus was concluded to occur principally through a process of passive diffusion.

Bacillus↗
PubMed1961

Permeability of bacterial spores. II. Molecular variables affecting solute permeation.

Gerhardt, Philipp (University of Michigan, Ann Arbor) and S. H. Black. Permeability of bacterial spores. II. Molecular variables affecting solute permeation. J. Bacteriol. 82:750-760. 1961.-More than 100 compounds were tested for their uptake by dormant spores of a bacillus. The extent of penetration was found to be dependent on at least three molecular properties: (i) The dissociation of electrolytes usually resulted in high or low uptake predictable from their charge. (ii) Lipid insolubility restricted permeation of small molecules. (iii) The molecular weight of unsubstituted glycol and sugar polymers exponentially limited penetration to eventual exclusion at mol wt above 160,000. The results were plotted as a generalized curve, calculations from which permitted an interpretation that the effective spore surface contains pores varying in diameter from 10 to 200 A.

Bacillus↗