[Comparative study of the dynamics of carbohydrate metabolism in the growth of Candida tropicalis yeasts on n-octadecane and glucose]. / Sravnitel'noe issledovanie dinamiki uglerodnogo obmena pri roste drozhzhei Candida tropicalis na n-oktadekane i gliukoze.

The dynamics of carbon metabolism was studied in Candida tropicalis growing on 14C-labeled n-octadecane and glucose by means of the technique of radioactive indicators. The kinetics of incorporation of 14C into the main groups of organic substances in the cell (proteins, nucleic acids+polysaccharides, lipids, free amino acids, organic acids, free carbohydrates+nucleotides) revealed differences in the rate of their synthesis and accumulation. The general features and the major differences in the pathways of carbon metabolism depended on the nature of a carbon substrate. If the yeast used n-octadecane as a source of carbon, the rate of synthesis of the lipid fraction was higher, and the ratio between its components changed as well as the rates of their synthesis.

Investigation of the turnover of the carbon of organic fractions of yeasts in the logarithmic phase of growth.

An investigation of the isotopic exchange (turnover) of carbon among the basic groups of organic substances of yeast biomass (proteins, polysaccharides, lipids, free amino acids, carbohydrates, and organic aicds) showed that in the presence of a carbon source and all the necessary nutrient elements in the logarithmic phase of growth of the culture, the bulk of the organic substances of the cell are extremely stable. Under these conditions, no appreciable utilization of the carbon of low-molecular-weight pools, nor any significant degradation of high-molecular-weight substances can be detected. Nor was there any redistribution of carbon-14 among individual components of the fraction of free amino acids and lipids. It was shown that the fraction of exchangeable carbon of the biopolymers of mature cells, like the fraction of the exchnage pool of low-molecular-weight substances, does not exceed 10% of the total carb-n of these substances. It is suggested that there is no mixing of the old and newly synthesized low-molecular-weight carbon pools in the parent cell, and all the components of the biomass of the daughter cells are synthesized chiefly from the carbon of the substrate.