[Lysosomal glycosidases, lactate dehydrogenase and creatine phosphokinase in experimental inflammation]. / Nekotorye lizosomal'nye glikozoidazy, laktatdegidrogenaza i kreatinfosfokinaza pri éksperimental'nom vospalenii.

Inflammation of rat hypodermic tissue was accompanied by an increase in activity of lysosomal glycosidases beta-D-galactosidase and beta-D-glucuronidase in the proliferating tissue and in some other preparations studied. Activation of lactate dehydrogenase/LDH/in exudate of inflamed tissues indicated apparently that the rate of redox reactions was elevated under conditions of the tissue proliferation. Decrease of creatine phosphokinase activity in blood plasma of experimental animals, which occurred simultaneously with the LDH activation, enabled to suggest the presence of compensatory mechanisms responsible for energy providing of the tissue proliferation.

On mechanisms determining the interrelationships between DNA and histone components of chromatin.

The relative affinity of histones for DNA was studied by the analysis of competitive histone binding to DNA in whole histone/DNA mixtures at physiological and low ionic strengths as well as in water. Use of polyphosphate in similar experiments, as a model of DNA deprived of hydrophobic functional groups allowed us to reject the hypothesis that hydrophobic DNA-histone interaction plays a decisive role in the determination of the relative affinity of histones for DNA, because the orders of histone preference for DNA and for polyphosphate were the same. The relative histone affinity for DNA does not depend on the secondary structure of DNA or on the ionic strength of salt solutions, though the differences in the histone affinities for DNA decrease on lowering the salt concentration. The binding orders of the first and the last molecules of histone type to DNA, studied at various DNA/histone ratios in the medium of physiological ionic strength, are the following: H3+H4, H2A+H2B, H1 and H3+H4, H2A, H2B, H1. In water the binding orders of the first and the last histone molecules to DNA are identical: H3+H4, H2A, H2B+H1. It is concluded that the relative histone affinity for DNA in water/salt solutions is determined by non-ionic interactions between histones bound to DNA. The folding of DNA induced by histone-histone interaction seems to lead to the increase in the correlation between amino acid residues in the histone regions bound to DNA and the ionic DNA-histone interaction becoming stronger.

[Changes in the matrix properties of chromatin during aminoazocarcinogenesis]. / Izmenenie matrichnykh svoistv khromatina v protsesse aminoazokantserogeneza

Male rats were on a diet containing 3-methyl-4-dimethylaminoazobenzol, a carcinogen. There were found no changes either in the electrophoretic total spectrum of deoxyribonucleoprotein (DNP) or in nonhistone proteins; the character of DNA and DNP melting curves or the matrix capacity of DNA extracted from the rat liver also remained unchanged. DNP of the tumour tissue acted more actively in the capacity of the matrix for the RNA synthesis in vitro in the system with the animal or bacterial RNA-polymerase with low substrate concentrations (2-10-5 M); but with high concentrations of each one of the substrates (2-10-3 M) RNA synthesis was the same as in control. With nuclear lysis in the solution with alkaline pH the percentage of RNA-polymerase activity, which it was possible to extract from the complex with chromatin, decreased considerably in rats given carcinogen.

[Effect of embichin (HN2) and its monofunctional analog (HN1) on chromatin and DNA matrix activity in an in vitro RNA-polymerase system]. / Vliianie émbikhina (HN2) i ego monofunktsional'nogo analoga (HN1) na matrichnuiu aktivnost' khromatina i DNK v RNK-polimeraznoi sisteme in vitro

Embichin inhibited the matrix activity of chromatin and DNA in the RNA-polymerase system in vitro much more than its monofunctional analogue. Chromatin possessed a greater sensitivity to the action of embichin in comparison with the deproteinised DNA. However, with the action of a monofunctional embichin analogue there was a greater reduction of the matrix activity of DNA in comparison with chromatin. The depression mechanism of the matrix activity of chromatin with the action of embichin was apparently associated with the capacity of the latter to form the DNA-protein bonds in the chromatin composition.

[Changes in RNA synthesis at early stages of aminoazocancerogenesis]. / Izmeneniia v sinteze RNK rannikh stadiiakh aminoazokantserogeneza

A single injection of the carcinogen 3'-methyl-4-dimethylaminoazobenzene (3'MDAB) or its non-carcinogen analogue 2-methyl-4-dimethylaminoazobenzene (2-MDAB) 300 mg/1000 g body weight led to the increase in the RNA-synthetic capacity of liver cell nuclei in vitro. No differences were found in the ribonuclease activity; in the template activity of DNA and DNP with E. coli RNA-polymerase, and in the melting temperature of DNA and DNP in the presence of 3'MDAB and in the control. The apparent value or Km of the RNA synthesis reaction are equal both for the control animals and those treated with 3'MDAB, but Vmax is lower in the control. It is suggested that the increase of RNA synthetic capacity of the nuclei of rat liver cells, found in vitro at early stages of the carcinogen (3'MDAB) action, should be regarded as the manifestation of its toxic effect and is proposed to be due to the increase of the concentration of RNA-polymerase which is capable to catalyse the RNA synthesis in nuclei.