[The reproduction of the hepatitis A virus in cell cultures]. / Reproduktsiia virusa gepatita A v kletochnykh kul'turakh.

A comparative analysis of reproduction of 9 strains of hepatitis A viruses (HSA-15, CF-979, MI, MBB 11/5, H-141, KMW-1, GBM, IH-26, WR-61) from different regions of the world in cell cultures (PLC/PRF/5, HEL-240, FRhK-4, MK) revealed the differences in the capacity of the viruses for reproduction in these cell lines. The factors influencing HAV reproduction in cell cultures such as temperature, medium, and sera were studied. In one-cycle infection, accumulation of vRNA and formation of virus particles were analysed.

[The adaptation of an isolate of the hepatitis A virus to reproduction in cell cultures]. / Adaptatsiia izoliata virusa gepatitia A k reproduktsii v kletochnykh kul'turakh.

A HAV strain derived from a patient in Moscow multiplied in a continuous cell line PLC/PRF/5 at 32 degrees C (variant MI-1) and at 37 degrees C (variant MI-1.1). These two variants of the strain MI retained the ability for reproduction both at 32 degrees C and 37 degrees C after passages in cell culture. The strain MI also replicates in MK cells. Negative results on HAV cultivation were obtained in HEF-240 and FRhK-4 cell cultures. The MI-1 and MI-1.1 variants are typical of hepatitis A viruses by their physicochemical properties, the results of ELISA, protein electrophoresis and dot hybridization tests.

[Cultivation of hepatitis A virus in various cell lines and isolation of DNA sequences]. / Kul'tivirovanie virusa gepatita A v razlichnykh kletochnykh liniiakh i poluchenie DNK-posledovatel'nostei.

Using the MBB/11/5 strain originally adapted to the PLC/PRF/5 cell line, reproduction of the virus in diploid cells of human embryo fibroblasts, continuous primate lines (RAMT, FRhK-4) and human urinary bladder tumor (T-24) lines was studied. We obtained HAV DNA sequences (about 99% from vRNA) for the MBB/11/5 strain which were used as a probe for demonstration of vRNA synthesis in the infected cells.

[Analysis of ribonucleoproteins of influenza virus containing genomic and complementary RNA]. / Analiz ribonukleoproteidov virusa grippa, soderzhashchikh genomnye i komplementarnye im RNK.

The density and sedimentation characteristics of ribonucleoproteins (RNP) containing genomic RNA from influenza virus and RNA complementary have been studied. Radioactive RNA from infected cells has been used for analysis. RNA classes of interest were isolated by reannealing with abundant nonradioactive genomic and complementary RNA and separation of resulting duplexes in electrophoresis. The RNP containing antigenomic virus-specific RNA are practically identical to "genomic" RNP for their sedimentation and density characteristics. The "plus" RNP is characterized by the stoichiometric mode of RNA protein interaction.

[Synthesis of virus-specific and cellular proteins in the presence of bonafton]. / Sintez virusspetsificheskikh i kletochnykh belkov v prisutstvii bonaftona.

Inhibition of the synthesis of virus-specific proteins of influenza A/WSN/33 virus in the cells of chick embryo fibroblasts and in continuous cells of dog embryonal kidney was discovered as was a negligible inhibition of the synthesis of cell proteins in the presence of an original synthetic antivirus drug bonaphthon. Experiments were made to attain selective inhibition of individual virus-specific proteins of influenza virus in these cultures. In model experiments in vitro in a cell-free protein-synthesizing system, bonaphthon was demonstrated to inhibit translation of RNA-virus of encephalomyocarditis on the virus template without affecting translation on the cell template of hemoglobin mRNA.

[Influenza virus replication in the presence of bonafton and other inhibitors of macromolecular synthesis]. / Repliktsiia virusa grippa v prisutstvii bonaftona i drugikh ingibitorov sinteza makromolekul.

Formation of virus-specific RNAs in the presence of bonafton, actinomycin D, and cycloheximide was studied. The degree of bonafton inhibition of the synthesis of the genome and complementary RNAs in the nucleus and cytoplasm of the infected cells varied. The effect of bonafton on replication and transcription of influenza virus differs from that of actinomycin and cycloheximide. Bonafton appears to disturb the regulation of these processes, specifically inhibiting the synthesis of individual fragments of viral RNA.

[Role of individual genes in the manifestation of the pathogenicity of influenza viruses]. / Rol' otdel'nykh genov v proiavlenii patogennosti virusov grippa.

The study elucidated the role of individual genes in manifestation of mouse pathogenicity by A/PR/8/34 and A/Seal/Massachusetts/1/80. The viruses were studied by the methods of recombination and molecular hybridization. The gene analysis showed that in a permissive system the pathogenicity of A/PR/8/34 strain was not associated with HA and NA surface glycoproteins. Gene P1 plays the decisive role in manifestation of pathogenicity of this strains.

[Parent and recombinant influenza virus A strains differing in the degree of remantadine sensitivity]. / Izuchenie roditel'skikh i rekombinantnykh shtammov virusa grippa A, razlichaiushchikhsia po stepeni chuvstvitel'nosti k remantidinu.

The pattern of inheritance in recombination of various degrees of sensitivity of influenza viruses to remantadine was studied and the genes responsible for the manifestation of this character with regard to the degree of the strain sensitivity to the inhibitor were determined. The results suggest that resistance to 10 microgram/ml remantadine in most cases was determined by the inheritance of the gene coding for the membrane protein, whereas the sensitivity to 10 microgram/ml remantadine most frequently correlated with inheritance of hemagglutinin of the strain sensitive to this inhibitor. The resistance to high remantadine concentration was shown to have features of a polygenic marker as indicated by the occurrence of intermediate forms among the recombinants. Influenza A (H1N1) viruses and strains with the antigenic structure of A (H3N2) isolated in 1979-1981 were more resistant to remantadine, in some cases even to subtoxic concentrations of it. Influenza A (H2N2) and A (H3N2) as a rule were sensitive even to low concentrations of inhibitor.

[Limitations in the translation of influenza virus mRNAs in infected cells]. / Ogranicheniia transliatsii informatsionnykh RNK virusa grippa v zarazhennykh kletkakh.

The monolayer cultures of chicken embryonic cells were infected with influenza virus and 6 hrs after the infection the relative concentrations of viral mRNAs and the relative rates of virus-specific protein synthesis were determined. For this purpose the infected cells were incubated under conditions of continuous labelling of RNAs by the radioactive precursor; the mRNA fraction was obtained by hybridization of total RNA of infected cells with non-labelled RNA of viral particles and the individual mRNAs were fractionated by polyacrylamide gel electrophoresis of RNA duplexes. The proteins from infected cells were labelled by [14C] amino acids for a short time and the individual virus-specific proteins were separated electrophoretically. There was no correlation between the rates of virus-specific protein synthesis and the relative concentrations of corresponding mRNAs. This indicates the regulation of virus-specific protein synthesis at the post-translational level.

[Action of actinomycin and alpha-amanitin on the RNA transcription of the influenza virus]. / Deistvie aktinomitsina i al'fa-amanitina na transkriptsiiu RNK virusa grippa.

Complete (template RNA) and incomplete (messenger RNA) transcripts were separated by electrophoretic fractionation of RNA-hybrids containing unlabeled genome RNA of influenza virus and virus-specific antigenome 3H-RNAs obtained from infected cells. Incubation of the infected cells in the presence of actinomycin D or alpha-amanitine was shown to inhibit selectively viral mRNA synthesis. It is suggested that the synthesis of mRNA and template antigenome RNA of influenza virus is initiated by different mechanisms.