[Macromolecular synthesis and cell division in Escherichia coli in the lag-phase of diauxie]. / Sintez makromolekul i delenie kletok u Escherichia coli v lag-faze pri diauksii.

The pulse incorporation of radiolabelled mannitol, glycerol, thymidine, uridine and protein hydrolysate has been studied during the Escherichia coli growth. The incorporation of carbohydrates and predecessors is sharply changed before and after lag-phase, that is due evidently to the partial synchronization of cell population. Three cell divisions have been found: before lag-phase (determined by the curve of optical density), at the end of it and after it termination. Cell division is accompanied by removal of catabolic repression from glycerol utilization, by increase of protein, RNA and DNA synthesis rates. The rates of biopolymer synthesis decrease sharply at the beginning of lag-phase, but DNA synthesis is going on at a rather high level.

[Development of catabolic repression during Escherichia coli growth on a carbohydrate mixture]. / Issledovanie razvitiia katabolitnoi repressii pri roste Escherichia coli na smesi uglevodov.

During the cell growth with mixture of three sources of carbon (mannit-arabinose-glycerol, glucose-sorbite-glycerol, glucose-sorbite-galactose) the components of the mixture have been found to be utilized in series. After using up the first, the repression is eliminated unselectively in utilization both the second and the third. Then after the lag-period the utilization repression of the third carbon source by the second one occurs. The phenomenon of "remaining repression" consisting in that at the cell growth with mixture of mannite and sorbite after using up the first carbohydrate the cells cannot start utilizing the second has been described.