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N Oker-Blom

Publications and source records attributed to N Oker-Blom.

At least 19 recordsLinked to original sources
PubMed1991

[Not Available].

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Finland↗
PubMed1987

[Not Available].

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Allergy and Immunology↗
PubMed1983

Avian acute leukemia virus OK 10: analysis of its myc oncogene by molecular cloning.

Several DNAs representing the genome of the avian acute leukemia virus OK 10 were isolated by molecular cloning from a transformed quail cell line, 9C, which contained at least six OK 10 proviruses. Recombinant lambda phages harboring the OK 10 genome and additional flanking cellular DNA sequences were studied by restriction endonuclease mapping and hybridization to viral cDNA probes. Six of the clones represented complete proviruses with similar, if not identical, viral sequences integrated at different positions in the host DNA. The organization of the OK 10 genome was determined by electron-microscopic analysis of heteroduplexes formed between the cloned OK 10 DNA and DNAs representing the c-myc gene and the genomes of two other avian retroviruses, Rous-associated virus-1 and MC29. The results indicated that the OK 10 proviral DNA is about 7.5 kilobases in size with the following structure: 5'-LTR-gag-delta polmyc-delta env-LTR-3', where LTR indicates a long terminal repeat. The oncogene of OK 10, v-mycOK 10, forms a continuous DNA segment of around 1.7 kilobases between pol and env. It is similar in structure and length to the v-myc gene of MC29, as demonstrated by restriction endonuclease and heteroduplex analyses. Two of the OK 10 proviruses were tested in transfection experiments: both DNAs gave rise to virus with the transforming capacities of OK 10 when Rous-associated virus-1 was used to provide helper virus functions.

Animals↗
PubMed1981

Avian acute leukemia virus OK10 has an 8.2-kilobase genome and modified glycoprotein gp 78.

We have analyzed the structure of OK10-BM virus, an avian acute leukemia virus produced by a bone marrow-derived cell line of macrophage origin, and compared it with that of OK10 AV, an associated virus originally present in the OK10 virus stock. The RNAs of OK10-BM virus and OK10 AV had the same mobility in agarose gels, corresponding to 8.0 to 8.5 kilobases, a size considerably larger than that of the transforming component (5 to 6 kb) of most other avian acute leukemia viruses. Fingerprint analysis showed a close relationship between OK10-BM virus and OK10 AV RNAs. The polypeptide compositions of OK10-BM and OK10 AV viruses were similar except for the envelope glycoproteins. In analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the large envelope glycoprotein of OK10-BM virus migrated at M(r) = 78,000 (gp78), whereas OK10 AV had the characteristic 85,000-dalton glycoprotein (gp85) of nondefective avian leukemia viruses. gp78 was weakly labeled with methionine, glycine, proline, or mannose, suggesting that purified OK10-BM virus had reduced amounts of the modified envelope glycoprotein. In cell-free rabbit reticulocyte lysates, OK10-BM virion RNA directed the synthesis of a 200,000-dalton polypeptide (p200), a 180,000-dalton polypeptide (pr180), and a 76,000-dalton polypeptide (pr76), whereas OK10 AV RNA gave rise only to pr180 and pr76, suggesting that p200 may represent an OK10-BM-encoded transforming protein. No biochemical evidence for the presence of an associated helper virus was found in the OK10-BM virus population produced by the macrophage cell line. However, when OK10-BM virus was serially passaged in chicken embryo fibroblasts, a virus having structural properties similar to those of OK10 AV (OK10 AV-specific oligonucleotides and gp85) appeared after three passages. Moreover, nonproducer clones of transformed cells could be readily obtained in OK10-BM virus-infected quail cell cultures. It is thus likely that the bone marrow-derived macrophage cell line produces a transforming virus defective in its env gene and low amounts of an associated helper virus, which upon transfer to fibroblasts is preferentially replicated.

Animals↗
PubMed1980

Stable bone-marrow-derived cell line producing transforming avian acute leukemia virus OK 10.

A stable bone-marrow-derived cell line, OK-BM, producing transforming avian acute leukemia virus OK 10, was established. The cell line has been maintained in culture for over 4 years and 405 passages. The cells grow rapidly in suspension, have a low serum requirement, display a uniform morphology and perpetually release transforming OK 10 virus. No transforming helper virus was detected by interference assay. The cells have a chromosome complement of the chicken. Characterization of the cells indicates that they are of myeloid origin and have properties characteristic of proliferating transformed macrophages.

Animals↗
PubMed1980

Nephropathia epidemica: detection of antigen in bank voles and serologic diagnosis of human infection.

An indirect immunofluorescence test for detection of serum antibodies specific for nephropathia epidemica (NE) has been developed with use of acetone-fixed cryostat sections of the lungs of bank voles (Clethrionomys glareolus) that had been trapped from the NE-endemic area in Finland as antigen. NE antigen was detected as distinct fluorescence in the cytoplasm of alveolar and macrophage-like cells. The 16 patients studied included typical cases from an endemic area, cases from a family outbreak, and cases in a laboratory staff which had had close contact with infected bank voles. Antibodies reacting with antigen in the lung sections developed in all of the patients but they were not found in the preimmune sera of the patients, in the sera of patients with other renal diseases, or in the sera of healthy individuals, with the exception of a member of the laboratory staff who had lived in the endemic area for 20 years. No specific IgM antibodies to NE could be detected. The rise in titer of antibodies to NE was characteristically prolonged, and elevated antibody levels persisted for many years.

Adult↗
PubMed1980

Bunyaviridae.

The family Bunyaviridae comprises over 200 viruses (serotypes, subtypes, and varieties) that infect vertebrates and/or invertebrates. Four genera of viruses have been defined (Bunyavirus, Nairovirus, Phlebovirus, and Uukuvirus). The main characteristics of the member viruses are: (i) the virus particles are for the most part uniformly spherical, 80-110 nm in diameter, and possess a unit membrane envelope from which protrude polypeptide spikes 5-10nm long; (ii) the viruses have three helical nucleocapsids, often in the form of supercoiled circles, each consisting of a single species of single-stranded RNA, major nucleocapsid polypeptide, N, and at least in some cases minor amounts of a large polypeptide which may be a transcriptase component; (iii) the genome is composed of three species of RNA (L, large; M, medium; and S, small), organized in end-hydrogen bonded circular structures; (iv) most viruses have three major virion polypeptides (N, and two surface polypeptides, designated G1 and G2); (v) for at least some member viruses, the virions have been shown to contain an RNA-directed RNA polymerase, believed to be responsible for the synthesis of viral complementary mRNA, so that bunyaviruses are considered to be negative-stranded viruses; (vi) at least some bunyaviruses are capable of heterologous virus genome segment reassortment and can form recombinant viruses at high or low frequency; (vii) viruses appear to mature primarily at smooth membrane surfaces and accumulate in Golgi vesicles and saccules, or nearby; (viii) transovarial, venereal and/or transstadial transmission in arthropods has been shown to occur for some members of the family.

Bunyaviridae↗
PubMed1978

OK 10 virus, an avian retrovirus resembling the acute leukaemia viruses.

The OK 10 virus complex was isolated from a liver tumour of a chicken which, as an embryo, had been inoculated intravenously with a field isolate of an avian leukosis virus. The OK 10 virus complex contains at least two viruses: the interference assay and serum neutralization test indicate that the helper virus belongs to subgroup A. One of the viruses, OK 10 V, induces distinct foci in chick embryo cells under agar overlay and cells from the foci form colonies in soft agar. These properties allow in vitro assay of the virus. Injection of virus or infected cells into chicks induces acute leukaemia but no local tumours. Another virus, OK 10 AV (associated virus), comprises about 99% of the OK 10 complex. The virus does not induce foci in chick embryo cells. In chickens it causes leukosis 17 months after injection. Electron micrographs of OK 10 virus stocks show typical C type virus particles. These particles have a density of 1.16 g/ml and contain 70S RNA which, after heat denaturation, releases type b RNA subunits. The OK 10 virus complex apparently represents a strain of acute leukaemia viruses.

Alpharetrovirus↗
PubMed1978

Togaviridae.

The family Togaviridae is described; it contains four genera--Alphavirus, Flavivirus, Pestivirus and Rubivirus--and additional members. The main characteristics of the family are as follows: single-stranded, linear RNA, molecular weight about 4 X 10(6). Virions have isometric nucleocapsids surrounded by a lipoprotein envelope containing host cell lipid and virus-specified polypeptides including one or more glycopeptides. Virions yield infectious RNA. There are at least 80 members; all the alphaviruses and most flaviviruses are arboviruses in the biological sense.

Arboviruses↗
PubMed1975

Morphological changes in chick embryo cell cultures induced by avian leukosis viruses.

Morphological alterations were observed after 5-15 serial passages of cells infected with three different strains of avian leukosis virus: OK 10, an A subgroup virus isolated from a natural infection; RAV-1, an established laboratory strain of the A subgroup, and RAV-2, a laboratory strain of the B subgroup. The infected cells had a prolonged lifespan of approximately 28 passages, compared to 14 passages for control cells. However, the altered cells had none of the attributes of transformed cells, such as growth in soft agar, loss of contact inhibition, tumor formation in chickens, or loss of fibroblast surface antigen. Therefore, we refer to the changes as conversion rather than transformation. The morphological changes differed depending upon the subgroup of the inducing virus. Cells converted with the A subgroup viruses were uniformly epitheloid whereas cells converted with the B subgroup virus were less uniform in size and shape. We speculate that an event similar to conversion may take place in vivo and contribute to the oncogenicity of leukosis viruses.

Animals↗