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Biomedical subjects

L V Uryvaev

Publications and source records attributed to L V Uryvaev.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Isolation of interferon messenger RNA and the synthesis of the double-stranded DNA product].

The data on preparation of the fraction of "enriched" interferon messenger RNA of chick fibroblasts by fractionation of biologically active RNA molecules by molecular weight are presented. The conditions of enzymatic synthesis and characteristics of the single- and double-stranded DNA product are described. The ways of producing more highly specific messenger RNA and DNA products are discussed.

Animals↗
PubMedDate not supplied

[Polyadenylation of influenza virion RNA in an in vitro system].

A method for isolation of terminal polyriboadenylate transferase from E. coli cells (MPE 600) is presented. The specific activity of the enzyme yield at the terminal stage was 933 units per 1 mg of protein. Analysis of polyadenylated in vitro virion RNA of influenza virus A/USSR/90/17 strain in polyacrylamideagarose gel (2.2%-0.6%) in the presence of 6 M urea showed all the 8 fragments of genome RNA to be adenylated, their sizes being retained with regard to the distribution in gel of the initial RNA fragments. In vitro polyadenylated virion RNA was an effective matrix in reverse transcription reaction with RNA-dependent DNA-polymerase using oligo (dT) as a primer. Complementary DNAs obtained in this way may be the starting material for synthesis of double-stranded DNAs and subsequent construction of recombinant DNAs containing influenza virus genetic information.

Avian Myeloblastosis Virus↗
PubMedDate not supplied

[Persistence of the Japanese encephalitis virus in L929 cells. Correlation of viral and cellular factors].

The paper presents the results of the study of the first stage of Japanese encephalitis (JE) virus persistence in cultures of L929 cells. The main parameters of the establishment and development of JE virus persistence in these cells characterizing the system as a chronically infected one. A possible role in the mechanism of persistence of various cellular and viral factors: interferon, ts-mutants, defective particles, was studied. Interferon was shown to be the main factor of virus carrier state perpetuation in the L-JE system. The role of defective particles, ts-mutants, and possible association of JE virus genome with nuclear DNA of L929 cells in the mechanism of persistence is discussed.

Animals↗
PubMedDate not supplied

[Incorporation of a DNA replica of the genome of the tick-borne encephalitis virus into cellular DNA].

DNA from mouse cells chronically infected with tick-borne encephalitis (TBE) virus was treated with restrictases, the resulting fragments were fractionated by size by gel electrophoresis, denaturated, and transferred from gel on nitro-cellulose filters. The fragments containing virus-specific sequences were detected by hybridization with 32P-DNA replicas of TBE genome RNA synthesized using reverse transcriptase. The presence of virus-specific sequences in DNA fragments from chronically infected cells proves the possibility of integration of DNA-replicas of TBE virus genome and genome of chronically infected cells.

Animals↗
PubMedDate not supplied

[Comparative analysis of the virus-specific proteins of cells infected with untypable herpes simplex virus strains].

Herpes simplex viruses of the so-called intermediate types were typed by analysis of virus-specific proteins of the infected cells. The results obtained correlate well with the results of typing of these strains by DNA analysis using restriction endonucleases. Strain differences of virus-specific proteins of herpes simplex virus of both types were established.

Cell Line↗
PubMedDate not supplied

[Modeling chronic infection in a T-lymphocyte-Venezuelan equine encephalomyelitis virus system].

A model of chronic infection in the system of T-lymphocyte--VEE virus was made. Production of infectious VEE (up to 6.0 lg PFU/ml), tissue culture interferon levels (less than 10 units/ml), accumulation of virus-specific antigen in chronically infected continuous human T-lymphocytes (78%) were studied. The presence of virus-specific sequence in DNA from infected cells was studied by the method of molecular hybridization and found not to exceed one DNA replica of virus genome per three cells of chronically infected T-lymphocyte culture.

Cells, Cultured↗
PubMedDate not supplied

[Chronic tick-bone encephalitis virus infection in continuous human lymphocyte lines studied by molecular hybridization].

Chronic infection with tick-borne encephalitis virus (Sophyin strain) has been established in continuous lines of human lymphocytes (of T- and B-origin). In 3 lines under study, the cultured virus at the level of the 15th passage had a titre of 7.22-8.02 lg LD50ml, the virus-specific antigen was determined in the cytoplasm of 80% of T-lymphocytes (line 1387). The method of RNA-DNA hybridization demonstrated the presence of virus-specific sequences in DNA preparations from infected cells in amounts not exceeding 1 copy of virus genome per 10-25 cells.

Cell Line↗
PubMedDate not supplied

[Further study of spontaneous virus production using transplantable HEp-2 cells as a model].

Two maxima of optic density were observed at zones of gravity 1.27 g/ml and 1.15-1.16 g/ml by sedimentation equilibrium in sucrose gradient of cultural fluid, obtained from the transplantable cells of the HEP-2 strain and concentrated by ultracentrifugation. These fractions thus isolated were tested for presence of RNA- and DNA-dependent DNA-polymerase. The structures with the density of 1.15-1.16 g/ml were identified with the oncornaviruses on the basis of characteristics flotating density, presence of RNA-dependent DNA-polymerase. Analyses of products of RNA- and DNA-dependent polymerases reaction, flotating density of oncornaviral nucleotides in sucrose and CsCl gradients are presented. The optimal conditions for reverse-transcriptase reaction of virions of D type viruses are characterized.

Cell Line↗
PubMedDate not supplied

[Amplification of the activity of HIV-1 isolates purified from seropositive children after cryopreservation of persistently-infected cells].

HIV-1 strains MC-1974 and MC-1978 were isolated from children infected in hospital. Both children presented with symptoms of HIV infection by the moment the blood samples for virus isolation were collected. In vitro the isolated strains showed weak infective activity and caused no cytopathic effect in sensitive cells. It may be explained by azidothymidine antiviral therapy or by initial immunodeficient status of both children not caused by HIV infection. Virus activity was enhanced in both cultures after reactivation of Jurkat-tat cells persistently infected with MC-1974 and MC-1978 strains after cryopreservation. Viruses isolated from culture fluid effectively infected Jurkat-tat cells. The infection was associated with formation of syncytia, accumulation of viral particles detected by electron microscopy and of intracellular antigens detected by fluorescent antibody technique and by immunoblotting. The results suggest the presence in the body of infected children and in Jurkat-tat-1974 and Jurkat-tat-1978 persistent lines of a viral genome containing all virusspecific genes necessary for productive expression of HIV-1.

Cell Line↗