[The microbiocenosis of the large intestine in animals with constant radiation exposure in the area of the Chernobyl Atomic Electric Power Station]. / Mikrobiotsenoz tolstogo kishechnika zhivotnykh pri postoiannom radiatsionnom vozdeistvii v zone ChAES.

State of microbiocenosis of large intestine in rats and furo subjected to constant combined irradiation has been studied in full-scale experiments in the emergency rooms of the Chernobyl NPP and in the nearest zone of its effect. The higher diversity of microflora (as compared to initial one), sharp increase of the amount of Candida genus fungi, a decrease of the number of bifidobacteria and increase of the amount of conditionally pathogenic flora were observed in rats with the dose of external irradiation of 1.43 Gr absorbed for 14 days. The expressed associative character of disbioses is distinctly traced. In furo affected by the radion exceeding the background level feeding with products contaminated by radionuclides leads to changes whose individual character corresponds to the picture of disbiosis under radiation injury.

[Change in the activity of tumor cell antigens as affected by treatment of the cells with the metabolic products of Bac. mesentericus AB-56]. / Izmenenie aktivnosti antigenov kletok opukholei pri obrabotke ikh produktami metabolizma Bac. mesentericus AB-56.

Tumour cells (ascitic A/Sn mouse lymphosarcoma ON-2), treated by the Bac. mesentericus AB-56 metabolism products used for the production of antitumour autovaccines were analyzed for their antigenic properties. The reactions of precipitation in gel, zonal and oncoming immunoelectrophoresis, passive hemagglutination as well as cytotoxic, absorption and transplantation tests were used. A considerable number of soluble and insoluble antigens inherent in intact tumour cells were inactivated by the products of microbial metabolism in the process of antitumour vaccine production, and modified antigens which induce synthesis of humoral antibodies in the syngenic system appeared.

[The effect of antitumor vaccine on the recurrence of solid tumors in mice subjected to surgery]. / Vliianie protivoopukholevoi vaktsiny na retsidivirovanie solidnykh novoobrazovanii u prooperirovannykh myshei.

The frequency of tumour recurrences in A/Sn mice with operated Ehrlich carcinomas and treated with lyophylized antitumour vaccine and trypan blue or both of them was investigated. The tumours in vaccinated mice relapsed by the 47th day after the operation in 10% of cases, in 50% of control animals, the injection of trypan blue increased the tumour recurrences by 20%. The antitumour effect of vaccination is associated with the enhancement of the activity of the cellular and humoral immune systems. The trypan blue inhibition of the macrophage function suppresses the antitumor activity of the immunity cellular components.

Study of MFD in Bacillus subtilis.

The frequency of UV-induced extragenic suppressor reversions to leucine independence in B. subtilis carrying a leu8 mutation decreased when irradiated cells were temporarily incubated in medium deprived of nitrogen sources. This mutation frequency decline (MFD) was inhibited by acriflavine and was poorly expressed in a uvr1 mutant. Consequently, MFD may be considered as the manifestation of an anti-mutagenic activity of excision repair. MFD was decelerated and even vanished in cells subjected to prolonged starvation of nitrogen sources before irradiation. MFD was accelerated in bacteria that were first irradiated and incubated in nutritional medium for at least 30 min. The stimulation of MFD by UV exposure was observed only in the uvr+ strain and depended on protein synthesis after irradiation. It is assumed that different rates of MFD in cells of various pre-radiation histories reflect different levels of the excision-repair activity inherent in these cells.

[UV-mutagenesis in Bacillus subtilis. VI. Mutagenesis under conditions of experimental delay of post-radiation DNA replication]. / Izuchenie UF-mutageneza u Bacillus subtilis. Soobshchenie VI. Mutagenez v usloviiakh éksperimental'noi zaderzhki postradiatsionnoi replikatsii DNK

To test a suggestion that mutation frequency decline (MFD) in UV-irradiated bacteria starved by nitrogen sources is caused by long delay of the first postradiation cycle of DNA replication, we used a strain 1201-05 of Bacillus subtilis 168 (ade6 met5tsdnaC) which does not synthesize DNA at 42 degrees C. In a suspension of UV-irradiated cells of this strain which is incubated at 42 degrees in liquid deprived by nitrogen sources, a decrease of frequencies of Ade+ and Met+ revertants is observed. This shows that the mechanism responsible for MFD normally operates at higher temperature. Such a level of decline is not observed in a suspension incubated in nutritional medium when the DNA replication is blocked by non-permissive temperature for the same period as in starved cells. On the basis of these facts it is concluded that MFD in suspension of bacteria starved by nitrogen sources can not be caused only by delay of postradiation replication of DNA.