[Formation of resting cells in microbial suspensions undergoing autolysis].

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].

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.

[Effect of membranotropic physiologically-active substances on the growth of Saccharomyces cerevisiae cultures].

The effect of Bacillus intermedius RNase and yeast autoregulatory d2 factor on growth of Saccharomyces cerevisiae is reported. It is shown that 0.01 microgram/ml of RNase stimulates the growth of the yeast on malt wort and molasses, the peak of the effect being observed for the enzyme added in the middle exponential phase.

[Regulation of Pseudomonas carboxydoflava growth and development by specific endogenous factors].

It was established for the first time that Pseudomonas carboxydoflava synthesizes a specific autoregulator factor (d) in the process of growth; the factor is a membrane-active compound according to the mode of its action. The regulatory action of the factor is manifested in limiting the number of the cellular population of the producing culture and in the capacity to induce the transition of vegetative cells into the resting state. The new forms are characterized by the abruptly decreased level fo metabolism, the high degree of light refraction, a peculiar ultrastructural organization, and the ability to retain viability for a long period of time.

[Change in the constructive metabolism and ultrastructural organization of Bacillus cereus cells under the influence of a specific autoregulatory factor].

It has been found for the first time that an increase in the concentration of a specific autoregulatory factor in the medium is responsible for the hypometabolic state of vegetative cells; no principal cellular biopolymers are synthesized at this state (DNA, RNA, proteins and phospholipids), and no cellular structures are degraded. When the culture reverses to vegetative growth observed in the same medium, synthesis of the biopolymers is intensified and changes are detected in the ultrastructural organization of the cellular membranous apparatus, the cytoplasm, the nucleoide and the cell wall.