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Biomedical subjects

A N Shkidchenko

Publications and source records attributed to A N Shkidchenko.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Comparative study of the physiological and biochemical characteristics of the varying ploidy of Saccharomyces cerevisiae strains in the process of their growth].

The growth of Saccharomyces cerevisiae strains having different ploidy was compared in the conditions of periodic cultivation, and was found to consist of two stages: (1) at the account of glucose utilization and (2) due to assimilation of cellular metabolites following a period of adaptation. The secondary growth was linear. The haploid, diploid and triploid strains differed in the character of growth, substrate utilization, the rate of respiration and the economic coefficient. Their qualitative protein composition was the same though certain changes were detected in the content of individual amino acids. The amount of essential amino acids (their sum) in proteins increased when the yeast started to oxidize cellular metabolites instead of glucose utilization.

Amino Acids↗
PubMedDate not supplied

[Dynamics of the interaction of Bdellovibrio bacteriovorus with the bacterial host under aerobic and anaerobic conditions].

Bdellovibrio bacteriovorus can interact with the host bacterium cells under aerobic and anaerobic conditions. The dynamics of the interaction between the parasite and the host depended on the regime of incubation. The latent period and the time at which Bd. bacteriovorus reached the stationary level became shorter under aerobic conditions. Lysis of the host bacterium cells under aerobic conditions proceeded more effectively, at a higher rate, and after a shorter period of the constant titre than under anaerobic conditions.

Aerobiosis↗
PubMedDate not supplied

[Physiology of the growth and supersynthesis of DNA-polymerase in Escherichia coli during 2-stage continuous cultivation].

The physiology of growth under the conditions of batch and continuous cultivation was studied with the recombinant strain of Escherichia coli CM 5199 capable of DNA polymerase I superproduction. The specific growth rate of the strain is 0.8 h-1 under the conditions of continuous cultivation which is almost 2.5 times greater than that in the exponential phase of batch cultivation. When the strain was cultivated at a flow rate above 0.3 h-1, the biomass concentration in the fermenter decreased and the culture was no more limited by the carbon source in the absence of other growth limiting components of the medium. Apparently, the metabolic product ceased to inhibit high growth rates of the culture under the conditions of continuous cultivation. The rate of DNA polymerase synthesis correlated with the specific growth rate and the respiration activity of the culture when the lambda pol A prophage was induced in the cells. The authors discuss the effectiveness of ribosome operation in the cells at a growth rate of 0.05 to 0.3 h-1 and the content of ribosomes at a higher growth rate in relation to DNA polymerase I synthesis.

Bacteriological Techniques↗
PubMedDate not supplied

[Effect of glucose metabolic products on the growth of a recombinant Escherichia coli strain--a superproducer of DNA-polymerase].

The dynamics of glucose metabolites production by Escherichia coli CM 5199 was studied under the conditions of batch and continuous cultivation. Acetate and ethanol were shown to be accumulated in the cultural broth in considerable amounts, and the rate of their synthesis was directly proportional to the specific growth rate of the culture. Acetate inhibited E. coli growth as was found in experiments conducted in a turbidostat regimen. As a result, the specific growth rate of the strain decreased during both batch and continuous cultivation.

Aerobiosis↗
PubMedDate not supplied

[Influence of cultivation conditions on the synthesis of trypsin inhibitor in the submerged culture of Actinomyces janthinus 118].

The influence of mass exchange and cultivation temperature on the synthesis of trypsin inhibitor in the submerged culture of Actinomyces janthinus was studied. Mass exchange parameters of the fermenter varied from 0.72 to 3.7 g O2 l/hr without oxygen limitations, and cultivation temperature ranged from 25 to 34 degrees C. The growth pattern, dynamics of substrate consumption and synthesis of trypsin inhibitor by the culture of Act. janthinus were shown to depend on mass exchange and cultivation temperature. With an increase in mass exchange the inhibitory activity reached maximum earlier but did not rise in its absolute value. With a temperature increase the inhibitory activity grew by 65%.

Actinomyces↗
PubMedDate not supplied

[Common action of limiting and inhibiting factors on the growth of yeasts in a continuous culture].

Candida utilis was cultivated under conditions of chemostat and continuous growth which was limited by phosphates. An excess of glucose inhibited the growth. The limiting and inhibiting factors produced simultaneous cooperative action. At a constant velocity of the medium flow, the concentration of biomass decreased, as a result of the inhibition of growth with residual glucose (0.96 and 1.36 per cent), by 5.5 and 15.6 per cent of the absolute value, respectively. The economic coefficient decreased in this case from 40 to 28 per cent. The inhibition of yeast growth resulted also in a decrease of phosphorus content in the cells; moreover, the cells could not utilize all oxygen dissolved in the medium.

Candida↗
PubMedDate not supplied

[Realization of the maximum specific growth rate of yeasts on optically heterogeneous media].

The method of controlling the rate of the nutrient medium flow was developed with respect to the level of heat release during yeast cultivation on the optically heterogeneous nutrient medium. This method of cultivation allowed attainment of the maximum specific rate of growth of Candida tropicalis which was estimated to be 0.45 hr-1 in the experiments.

Candida↗
PubMedDate not supplied

[Limiting the growth of Saccharomyces serevisiae yeasts under chemostat conditions by carbon and nitrogen sources].

Chemostat Saccharomyces cerevisiae cultures were obtained at D = 0.066 h-1 and growth limitation with ethanol and a nitrogen source with similar population densities. The threshold concentration of ethanol was 0.1 g/L and that of nitrogen 0.014 g/L. The optimal specific load of ethanol was 2.5--3.5 g/g biomass per hour with the economic coefficient of 40%. At the constant specific ethanol load, the economic coefficient changed at different rates of flow. The cultures differed in the content and amino acid composition of protein.

Amino Acids↗