[Ultrastructural changes in Bacillus megaterium cells immobilized in polyacrylamide gel].
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Biomedical subjects
Publications and source records attributed to K A Lusta.
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A complex of polyphosphatase with E. coli membranes has been isolated and studied. It is shown by gel-filtration through G-200 Sephadex and centrifugation in sucrose concentration gradient that about 5% of polyphosphatase total content in cells is bound with the heterogenous fraction containing smooth membranes and the ribosome-membrane complex. On the basis of the data obtained it is suggested that the formation of a complex of polyphosphatase with membranes is a stage of synthesis and secretion of this enzyme to protoplasm.
The enzymatic activity, viability, respiratory activity, and ultrastructural changes in saccharomyces cerevisiae VKMu-488 cells, which carry out the stereospecific 17 beta-reduction of methyl esters, was studied. The 17 beta-hydroxysteroid dehydrogenase activity of yeasts in gel is four times lower than that of free cells and is unstable. The decrease in the viability and respiratory activity immediately after immobilization, the disturbance in the ultrastructure of the cells in gel along with the progressive lysis of the cells in the course of the transformation indicate that polymerization has a stressful effect on this culture. It was found that the immobilized yeasts can grow on the surface of the gel in the presence and absence of nutrient medium. A single incubation of granules containing cells in nutrient medium greatly stabilizes the original activity of the immobilized cells. The activation and stabilization of the activity are probably due to the participation of a heterogeneous population in the transformation: the original population incorporated into the gel and the new population which grows in the gel after immobilization as well as to the stability of the ultrastructural organization of this mixed population in the course of repeated transformations of secoketone.