[Effects of exogenous poly(A)+ mRNA on antigenic properties and growth of Krebs-2 tumor cells].

The treatment of Krebs-2 ascitic tumor cells (TC) with total RNA from the liver of Wistar rats (2 mg/ml) altered their antigenicity. As a result, the growth of treated TC in contrast with untreated TC was inhibited when transplanted i. m.

[A study of the mechanism of cyanide resistant oxidation of succinate from rat liver mitochondria in the presence of menadione].

Two operation regimes of the electron transport system were found in rat liver mitochondria during the cyanide-resistant succinate oxidation catalyzed by menadione. Under isotonic conditions, the mitochondria were found to contain two electron transport components, one of which was sensitive to mucidin, whereas the other one was inhibited by antimycin A. Both electron transport components were inhibited by thenoyltrifluoroacetone (TTFA).

[Increased content of nucleotide sequences in transcriptionally active DNA and poly(A)+-mRNA of the rat liver and a rise in its translation activity as affected by inducers].

Cortisol and 3'-methyl-4-dimethyl-amino-azobenzene induce an increase in the content of repeated sequences (RS) in transcriptionally active (TA) DNA, while the content of respective RS in potentially active DNA fractions enriched with regulatory regions of the genome decreases. RS content in induced poly A+-mRNA also rises, as determined by the nature of hybridization of respective c DNA with total DNA. The translation of induced poly A+-mRNA rises essentially, with the qualitative distinctions in in vitro synthesized protein product spectrum being absent.

[Detection of DNA sequences sensitive to glucocorticoids in the thymus of AKR mice and their inactivation in thymoma].

A high increase in transcriptionally active DNA fraction (TA DNA) has been detected in the thymus of young AKR mice and in thymoma. Hybridization of TA DNA with [32P] cDNA synthesized on poly A+-mRNA of cortisol-induced animals has shown that TA DNA of young AKR mice contains 40 times as much cortisol-activated repeated sequences (RS) as that of thymoma. The decrease of cortisol-activated (RS) in AKR thymoma TA DNA was found to be the result of their transition into transcriptionally inactive (TI) DNA.