[Formation of resting cells in microbial suspensions undergoing autolysis]. / Obrazovanie pokoiashchikhsia form v avtoliziruiushchikhsia suspenziiakh mikroorganizmov.

Under experimentally selected conditions favoring spontaneous or induced autolysis of cell suspensions, the asporogenous bacteria Escherichia coli and Methylococcus capsulatus, the bacilli Bacillus cereus (under conditions of suppressed sporulation), and the yeast Saccharomyces cerevisiae were shown to be capable of forming cystlike resting cells. Their number was influenced by (1) cell density in the suspensions; (2) the presence of Ca2+ ions in nutrient-limited medium; (3) pH of medium; and (4) autolysis rate, dependent on the concentration of oleic acid (a chemical analogue of the autolysis-inducing d2 factor) introduced into the cell suspensions.

[Formation of a resting form of Bacillus cereus and Micrococcus luteus]. / Obrazovanie pokoiashchikhsia form Bacillus cereus i Micrococcus luteus.

Under certain cultivation conditions, the bacteria Bacillus cereus and Micrococcus luteus form cystlike refractive cells (up to 60% of the total number) that retain viability over a long time, are metabolically inactive and thermotolerant and possess specific ultrastructure. These properties allow them to be attributed to a new type of resting forms of microorganisms.

[Tyrosol--the autoregulatory d1 factor of the yeast Saccharomyces cerevisiae]. / Tirozol--autoreguliatornyi faktor d1 drozhzhei Saccharomyces cerevisiae.

The autoregulatory d1 factor of the yeast, Saccharomyces cerevisiae, that induces the transition of vegetative cells into refractory resting forms, has been isolated from the cell-free culture medium as an individual crystalline compound. It has been shown to be 2-(4-hydroxyphenyl)ethane-1-ol which is also known as tyrosol. When added to the producer culture at 5-15 microM concentration, tyrosol stimulated the endogenous respiration of cells, but inhibited at 20-80 microM concentration. At 200-800 microM concentration, it induced the occurrence of resting forms. The action of tyrosol was not specific, for it also inhibited the cell respiration of the bacteria, Escherichia coli and Bacillus cereus, at 64-86 microM concentration.