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Biomedical subjects

M Nonoyama

Publications and source records attributed to M Nonoyama.

At least 163 records · Page 9Linked to original sources
PubMed1975

Latent genomes of Epstein-Barr virus.

Of the EBV DNAs in Raji cells that contained 50 to 60 viral genomes per cell, 90% were separated from high molecular weight cellular DNA by centrifugation in a neutral glycerol gradient after lysis of the cells by treatment with pronase and Sarkosyl, indicating that the major portion of the EBV DNA in Raji cells was not integrated linearly into cellular DNA.

Cell Division↗
PubMed1975

Alteration in Epstein-Barr virus-human lymphoid cell interactions caused by the presence of type-C viral genome.

We have recently established a cell line, designated FVNC, by infection of non-EBV-productive human lymphoid NC-37 cells with the type-C virus FLV. The FVNC cell line has been maintained free of detectable EBV- and FLV-related immunofluorescent antigens for three years but both viral genomes exist in the cells in a repressed form. The FVNC cells were morphologically similar to the uninfected NC-37 cells but a D-group chromosome change was consistently seen. The colony-forming capacity of FVNC cells in semi-solid agar medium was about 1/10 of that of NC-37, although the former grew rather faster than the latter in fluid culture. FVNC cells were three times more sensitive to EBV superinfection than NC-37, as shown by immunofluorescence. In addition, an obvious induction of FLV antigenic markers occurred in FVNC cells on exposure to EBV. Nucleic acid hybridization experiments showed a striking decrease in the number of EBV genomes in FVNC cells. The number of genomes was too small to be measured, but EBNA was clearly present in all FVNC cells as well as in NC-37 cells. The implications of these findings were discussed from the point of view of a possible co-carcinogenesis in man by EBV and the type-C virus.

Antigens, Viral↗
PubMed1974

Latent DNA of Epstein-Barr virus: separation from high-molecular-weight cell DNA in a neutral glycerol gradient.

Epstein-Barr virus DNA in virus non-productive cells was separated from high-molecular-weight cell DNA by sedimentation through a neutral glycerol gradient after gentle lysis of cells by Pronase and Sarkosyl. The isolated Epstein-Barr virus DNA had a density of 1.716-1.717 g/cm(3) in CsCl equilibrium centrifugation, which is very close to the virus DNA density of 1.718 g/cm(3). The results indicated that the majority of Epstein-Barr virus DNA in virus nonproductive cells is not covalently integrated into high-molecular-weight cell DNA.

Burkitt Lymphoma↗
PubMed1974

Replication of the resident repressed Epstein-Barr virus genome during the early S phase (S-1 period) of nonproducer Raji cells.

Replication of the resident repressed Epstein-Barr virus genome in synchronized nonproducer Raji cells was shown to occur during the early S phase (S-1 period) by hybridization of cell DNA with virus-specific complementary RNA (cRNA). The S-1 period was previously identified as the critical period for virus activation induced by thymidine analogues. The findings reported here and elsewhere are consistent with the proposal that: (i) virus activation is initiated at or near the site of association of the resident viral genome with cell DNA, (ii) replication of the resident virus genome in nonactivated cells is under cell control mechanisms, and (iii) the resident virus genome is physically associated with early replicating cell DNA.

Burkitt Lymphoma↗
PubMed1974

Control of transcription of the reovirus genome.

The ten double-stranded RNA segments of the reovirus genome are not transcribed at equal frequencies until later times during the course of infection. When an inhibitor of protein synthesis such as cycloheximide was added to infected cells at the beginning of infection, only four of the ten segments were transcribed. By two hr post infection, five and possibly seven of the segments were being transcribed. By four hr post infection all ten segments were being transcribed but not yet at equal relative frequencies. The transcription pattern at intermediate (4 hr) and late (10 hr) times were verified without using cycloheximide. A repressor present in the host cell may be responsible for controlling transcription of the reovirus genome.

Animals↗
PubMed1974

Host cell regulation of induction of Epstein-Barr virus.

When Epstein-Barr virus (EBV) negative cells (Raji) were treated with iododeoxyuridine, only the early antigen (EA) component was induced. There was no significant increase in EBV DNA and no virus particles were observed. Somatic-cell hybrids were prepared from the fusion of Raji and D98 cells (D98/Raji). When these cells were treated with iododeoxyuridine, early antigen EBV DNA, and virus particles were synthesized. These data suggest cellular control over the expression of the EBV genome.

Antigens, Viral↗
PubMed1973

Epstein-Barr virus: detection of genome in somatic cell hybrids of Burkitt lymphoblastoid cells.

Somatic cell hybrids of Burkitt lymphoblastoid cells, from which Epstein-Barr virus can be recovered, were examined for the presence of virus DNA by DNA-RNA hybridization. Four clones of hybrid cells, each negative for virus antigens by immunofluorescence, contained virus DNA in varying genomic equivalents. The number of virus genome equivalents increased in the hybrid cells after induction of virus with iododeoxyuridine.

Animals↗
PubMed1973

DNA of Epstein-Barr virus detected in tissue of Burkitt's lymphoma and nasopharyngeal carcinoma.

The association of Epstein-Barr virus (EBV) DNA with African tumors was examined by the method of hybridization with complementary RNA. 22 out of 23 biopsies of Burkitt's lymphoma and 18 out of 23 biopsies of nasopharyngeal carcinoma were found to contain EBV DNA. The number of EBV genome equivalents per cell ranged from four to 113. Five out of 24 other African tumors, two adenocarcinomas, and one each of melanoma, reticulum cell sarcoma, and carcinoma of the antrum, also contained EBV DNA.

Adenocarcinoma↗
PubMed1973

Reassociation kinetics for Epstein-Barr virus DNA: nonhomology to mammalian DNA and homology of viral DNA in various diseases.

The number of Epstein-Barr virus (EBV) genomes per cell in established leukocytic lines and tissue specimens has been evaluated by measuring DNA-DNA reassociation kinetics with hydroxyapatite chromatography. Under the proper conditions, this method is sufficiently sensitive to detect EBV DNA in the amount of 0.1 genome per cell. All the samples tested that have been suspected to be without EBV DNA by cRNA hybridization proved negative by this more sensitive specific analysis. These included Hela and Hep2 cells, a negative case of Burkitt's lymphoma, two negative cases of nasopharyngeal carcinoma, and two established human leukocytic lines. Homology tests conducted with single-strand-specific nuclease S1 indicated that the viral DNA from a nasopharyngeal carcinoma and infectious mononucleosis were more than 90% homologous to EBV DNA.

Animals↗