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Penetration of human immunodeficiency virus (HIV) into the cells of lymphoblastoid T-cell line H9 was studied using 35S-methionine-labeled virus by demonstration of virus-specific proteins in the cytoplasm of the infected cells. Purification of the virus by ultracentrifugation through 30% glycerol was shown to lead to virus aggregation and its partial destruction manifested by the loss of gp120 protein, therefore unlabeled concentrated virus was used mainly with subsequent determination of virus-specific proteins by immune blotting. The addition of Sendai virus inactivated with UV rays to HIV increased the amount of HIV associated with cells as well as the amount of virus-specific proteins in the cytoplasm of the infected cells.

In experiments with lysogenic cultures Pseudomonas aeruginosa and Escherichia coli K-12 proposed as a test for biological indication of relatively low doses of gamma-radiation, it was shown that when estimated by the criterion of prophage induction riboxine had a radioprotective action at nonlethal radiation doses. At the same time, when estimated by the criterion of the survival rate, riboxine produced the radioprotective effect at rather high radiation doses (survival rate of less than 10 per cent). It is suggested that riboxine is involved in the cell repair processes.

Induction of prophage in lysogenic cultures, Pseudomonas aeruginosa (strain PA01 (PM63)) and Escherichia coli K-12 (strain AB1157 (lambda) pKM101), was proposed as a test for biological indication of gamma-irradiation with relatively low doses. Sufficient resolving power (the sensitivity threshold of the method was 0.25 to 0.5 Gy) and relative simplicity of the practical use of the method were demonstrated. Within the dose range from 0.25 to 10 Gy, the relationship between the value of the prophage induction and radiation dose was linear.

DNA repair was explored in continuous cells withdrawn from gout patients. The data obtained were compared to those on primary cells (lymphocytes) from the same patients. Two continuous lines of fibroblasts obtained from the biopsy material of patients suffering from gout were examined for stability of reparation defects on long cell passage. The studies were made with 4 to 12 passages of patients' fibroblasts. The use of criteria reflecting certain stages of DNA repair (reparative synthesis of DNA, formation of induced DNA ruptures and their resynthesis during cell postincubation, reactivation and induced mutagenesis of measles vaccine virus in patients' cells) allowed confirmation of repair defect stability in gout patients' cells on their long passage. Based on the data on preservation of the repair defect on cell passage it is concluded that gout patients demonstrate the genetically determined impairment of the synthesis of DNA repair enzymes participating in the recovery of DNA impairments induced by UV radiation or UV mimetics.

In gamma-irradiated cells of Escherichia coli K-12 restriction alleviation of an unmodified phage lambda is only observed in AB1157 strain. No restriction alleviation by gamma-rays is registered in AB1157 mutants (rec A and ssb-1).

DNA repair activity in cells after gamma-irradiation or treatment with 4-nitroguinoline-1-oxide was studied by alkaline elution of cells lysed on membrane filters, as well as by reactivation and induced mutagenesis of vaccinia virus in lymphocytes and fibroblasts obtained in skin biopsy from patients with homocystinuria. Disorders of the repair were demonstrated in lymphocytes by using both criteria. In all fibroblast passages repair disorder was only found for gamma-irradiation, the repair activity being comparable with that of lymphocytes. The level of spontaneous and gamma-induced mutations in vaccinia virus propagated in fibroblasts was increased at later culture passages.

Ultrafiltration through hollow fibrous filters followed by purification in interrupted and linear urografin gradients yielded a Lassa virus suspension of high concentration. The use of gamma-irradiation for inactivation of the frozen virus suspension (-70 degrees C) caused no apparent structural changes of virions and made it possible to examine Lassa virus in electron microscope by negative staining. The observed virus particles in their morphology and sizes did not differ from previously described particles of other members of the Arenaviridae family. In ultrathin sections of Lassa virus-infected Vero cells, atypical virions were sometimes visible alongside with typical particles. Within one type of such particles no ribosome-like granules could be detected. Such "hollow" particles may possibly be defective virions. Another kind of atypical particles contained homogeneous electron-dense core and resembled mycoplasma. Of greatest interest are the particles with heterogeneous core in which "sandy" granules can be distinguished. The presence of greater amounts of uranophilic material than usually may be explained by getting into the virion in the process of its formation of a greater amount of genetic material than that present in typical virions.

Induction of lambda prophage in lysogenic E. coli cells exposed to ionizing radiation of different LET was studied as a function of dose I(D). Activities of pleiotropic RecA protein were shown to contribute to the shape of the I(D) curve. The experimental data were fitted by the function I(D) = alpha D(1-exp(-D0-1.D]exp(-beta D). Inducibility alpha increased with increasing LET which was related to the increased incidence of DNA lesions being a SOS-system call.

A study was made of the processes of repair, virus reactivation, and formation of sister chromatid exchanges (SCE) in blood cells of patients with schizophrenia after the effect of gamma-radiation and 4-nitroquinoline-1-oxide. These processes were estimated by 12 criteria. The mutagen-induced disturbances in the processes of repair and SCE formation were found in cells of patients with schizophrenia and were absent in the control cells of healthy donors.

In the process of studying phage--Salmonella derby plasmid interaction effect, it has been found that the absence of the plasmid blocks the adsorption step and the step of phage penetration into the cell. However, the lytic functions and those responsible in maintenance of the lysogenic state are independent of plasmid. Probably, resistance of plasmidless cells of S. derby to extracellular dp8 phage is mediated by the absence of plasmid-borne genes in S. derby coding for membrane peptides which are indispensible for adsorption and DNA penetration into the cell.

Lymphocytes of patients with gouty nephropathy were investigated using the criteria of sister chromatid exchanges (SCE) formation, rapidity of generation, virus reactivation, detection of the level of virus mutagenesis and DNA repair and replication synthesis in the experiments with some mutagens. Disorders, according to these criteria, were observed in the cells of all the patients. Cells of patients with gouty nephropathy may be used as a model to study DNA repair and replication mechanisms.

Two temperate bacteriophages, PP56 and PP71, specific for bacteria of Pseudomonas putida strain PpG1 have been isolated for the first time. Characterization of the phages was performed. Both of them accomplish stable lysogenization of P. putida PpG1 cells. The phages are inducible. Several groups of clear plaque (c) mutants of PP56 and PP71 with altered processes of establishment and maintenance of lysogenic state have been isolated, according to complementation test. The phages differ in following characters: 1) in morphology of mature phage particles (C and B types, according to Bradley classification); 2) in sizes and genome organizations: DNA of PP56 is permuted (up to 30%), its size is 45 kb, the size of terminal redundancy being 2.5 kb; there is no permutation in PP71 DNA of 48 kb and it has "cohesive" ends; 3) no DNA/DNA homology is shown in tests between PP56 and PP71 DNAs. All the data obtained permitted to consider the phages PP56 and PP71 to belong to different unrelated species (families).

Either the difference delta N of the content of free phage particles in the experiment and the control or K ratio of these values can be used to estimate the effectiveness of ionizing radiation or other agents inducing phage formation in a lysogenic bacterium culture. The estimation technique the results of which are nearly independent of the fluctuations in the number of phage particles in the control, the inductor dose being invariable, is the most adequate one. The induction of phage in E. coli K12 (lambda) culture by X-rays and magnetic field is an example illustrating that the K ratio, which can be called "the induction coefficient", is in a good agreement with the requirement mentioned above. A possible nature of the phenomenon observed is discussed.

In experiments with chemical mutagens (alkylating agents MNU, ENU, MMS and EMS), para-aminobenzoic acid (PABA) sharply inhibited the inducible processes in Escherichia coli, namely, mutagenesis, induction of lambda prophage and W-reactivation of UV-irradiated phage lambda. Based on experimental studies of E. coli strains deficient in different steps of DNA repair, the conclusion was made that PABA participates in regulation of the branch of DNA repair that is controlled by recA+ recF+ alleles.

The effect of pathogenic and noninfectious influenza viruses with different surface antigens on colony-forming stem cells of (CBA X C57BL/6)F1 mice was studied. Bone marrow cells were infected with A/PR8/34 (H1N1)/A/Krasnodar/101/59 (H2N2) viruses, a recombinant A/PK-6-3 (H2N1) strain thereof, A/Khabarovsk/933/77 (H1N1) strain; then they were inoculated intravenously to irradiated (820 rad) syngeneic recipients, and colony-forming units (CFU) were determined in the spleens 9 days after injection. Inoculation of bone marrow cells (2 X 10(5) per mouse) to the irradiated recipients immediately after mixing with a live A/Krasnodar virus heated at 56 degrees C, live A/PK-6-3, and A/Khabarovsk viruses resulted in suppression of formation of CFU and marked atrophy of the recipients' spleens. There was no suppression after the use in these experiments of the pathogenic A/PR/8/34 strain. Inhibition of CFU production in the spleen was observed after inoculation of the recipients with bone marrow cells incubated for 1 hour at 37 degrees C with A/PR/8/34, A/Krasnodar/101/59 viruses and the recombinant strain. Possible mechanisms of the suppressive effect of influenza A virus on CFU production in mice are discussed.