[Growth and spore formation in Bacillus thuringiensis at high substrate concentrations].

The work was aimed at studying the effect exerted by elevated concentrations of glucose, yeast extract and acetate on the growth of Bacillus thuringiensis subsp. galleriae, strain 69-6, and on the formation of spores and crystals by it. Glucose concentrations from 30 to 100 g per litre did not prevent spore formation.

[Cultivation of the producer of alpha-amylase Bacillus subtilis under batch and continuous conditions].

The growth of Bacillus subtilis FU-79 and its production of alpha-amylase (EC 3.2.1.

[Morphological changes in a chemostat culture of Candida utilis undergoing cyclic changes of pH and pO2].

The effect of cyclic pH and pO2 changes on the morphology of Candida utilis was studied with time intervals measured in minutes. The pH was varied from 4.5 to 2.

[Biological characteristics of the variants of Bacillus thuringiensis subsp. galleriae formed during continuous culture].

Bacillus thuringiensis subsp. galleriae S. variants formed during continuous cultivation differ from the parent culture in certain properties.

[Growth and development kinetics of Bacillus thuringiensis in batch culture].

The kinetics of Bacillus thuringiensis growth and its assimilation of nutrient substances were studied under the conditions of batch cultivation in a complex medium containing yeast extract and in a chemically defined medium with amino acids. The growth of B. thuringiensis can be divided into five phases: exponential growth; decelerated growth; stationary phase when protein crystals are formed; stationary phase when spores are formed; lysis of sporangia releasing spores.

[Variability of Bacillus thuringiensis under various growth conditions].

When a lysogenic culture of Bacillus thuringiensis subsp. galleriae 69-6 was grown under the batch conditions, 93-99% of cells in the population produced R-form colonies and ca. 1% yielded S-form colonies.

[Sporulation and crystal formation in Bacillus thuringiensis during growth limitation via nutrient sources].

The object of the work was to study the effect of limiting concentrations of glucose, yeast extract, phosphorus, magnesium and potassium on the growth, spore formation and crystal formation in Bacillus thuringiensis subsp. galleriae. The deficiency of the above components was shown to interfere in no way with the processes of spore and crystal formation.

[Chemical composition and morphological changes in the cells in a chemostat Candida utilis culture inhibited by zinc ions].

The effect of zinc ions on the physiological state of Candida utilis VKM Y-1668 was studied during its chemostat cultivation. The concentration of zinc ions was maintained at a constant level. Zinc was found to inhibit the growth at a concentration of 300 mg/l.

[Use of rifampicin for directed modification of the nucleotide composition of the cells of Bacillus megaterium and Candida utilis].

The object of this work was to study the effect of rifampicin on the physiological state of Bacillus megaterium and Candida utilis in chemostat and batch cultures. When B. megaterium is cultivated in a medium containing 1 microgram of rifampicin per litre, its metabolism changes, the pool of free nucleotides rises, and the content of RNA drops in response to the specific action of the inhibitor.

[Transitional states in a chemostat culture of Candida utilis].

Transient states of the chemostat Candida utilis 1668-3-37 culture were studied when its growth was limited by ethanol and an abrupt acidification of the medium from pH 5.0 to 2.2 was done or when the dilution rate was rapidly changed from D = 0.

[Periodic changes in the morphophysiological properties of chemostat culture of Candida utilis yeasts under alternating temperatures].

The object of this work was to find out whether it was possible to cultivate yeasts in chemostat in varying regime: at multiple changes to temperature from the optimal one (31 degrees C) to the supraoptimal one (37 degrees C) and back with a frequency comparable to the generation time; this regime was alternated during 32 generations. The cultures were compared with chemostat cultures grown in steady-state regimes at 31 or 37 degrees C. The value of Y, the composition of cells and morphometric characteristics were determined by the optical-structural computer analysis.

[Method of calculating the specific growth rate of microorganisms by measurements of the substrate or product concentration].

A procedure and formulae are proposed for calculating the specific rate of microbial growth; these are based on measuring the concentration of either a limiting substrate or a product involved in the growth of a microorganism. Only the concentrations of a substrate (S) or a product (P) are determined periodically in the course of the cultural growth whereas the biomass yield (chi) in the medium is established only after long time intervals. The proposed equations may be used for controlling the specific growth rate in large-scale processes by the concentration of a product (or a substrate) using a computer, as well as in laboratory studies of mu as a function of the conditions for growth of slowly growing microorganisms.

[Effect of the protein synthesis inhibitor chloramphenicol on the basic growth indices of continuous and periodic Bacillus megaterium cultures].

The action of chloramphenicol, a specific inhibitor of bacterial growth and an inhibitor of protein synthesis, was studied in the conditions of continuous and batch cultivation. Steady states of the population within the range of D from 0.2 to 0.

[Effect of Zn2+ on growth and the properties of Candida utilis in continuous cultivation].

The purpose of this work was to study the effect of zinc ions on the growth and physiological properties of the chemostat culture of Candida utilis BKM Y-1668. Zinc at a concentration of 250-300 mg/l was found to inhibit the growth of the culture. The resistance of the culture to zinc ions can be increased within 40 generations if the yeast is grown in the regime of chemostat and the concentration of zinc ions is gradually increased.

[Nonspecific stress in Candida utilis under growth inhibition by a specific inhibitor].

The physiological state of Candida utilis chemostat cultures was studied when the growth was limited with glycerol at D from 0.047 to 0.35 hr-1, and compared with the same cultures inhibited with cycloheximide.

[Effect of zinc ions on Candida utilis].

The effect of zinc on the growth of Candida utilis was studied as well as on the rates of RNA and protein synthesis, and the uptake of zinc ions by the cells. The kinetics of C. utilis growth inhibition by zinc ions can be described by the equation for noncompetitive inhibition of enzymatic reactions.

[Cell adhesion in a chemostat culture of Candida utilis under the influence of supraoptimal temperature and elevated acidity].

The effect of the supraoptimal temperature (38, 40 degrees C) on the chemostat culture of Candida utilis was studied. The above factor caused a part of the biomass to float as a thin layer of foam to the surface of the medium. After an hour, the concentration of the cells on the surface could be four times as high as that within the medium.