摘要:

Characteristics of over 1,150 phages have been categorized into 17 groups, based upon morphology and nucleic acid content. A scheme is presented for cataloging phage data for computer storage, retrieval, and sorting to be used in the development of a phage taxonomy and nomenclature.

ISSN:0300-5526    

DOI:10.1159/000149758

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

A comparative study of the structural polypeptides of purified human papilloma virus, rabbit papilloma virus, and simian virus 40 (SV40) was performed by electrophoretic analysis on 10% polyacrylamide gels containing sodium dodecyl sulfate either by Coomassie blue staining or byelectrophoresing purified virus preparations labeled with radioactive iodine. Analysis of human papilloma virus on stained gels revealed 6 bands with a major polypeptide of molecular weight 63,000 daltons comprising 60% of the virion protein. Analysis of rabbit papilloma virus on stained gels revealed 5 bands with a major polypeptide of molecular weight 60,000 daltons comprising 48% of the virion protein. Under conditions which yielded 6 polypeptides for SV40, in agreement with published data, 4 and 7 polypeptides were regularly detected in iodinated preparations of human and rabbit papilloma viruses, respectively. Isoelectrofocusing of iodinated virions revealed isoelectric points of pH 3.7 for SV40 and pH 4.0 for both rabbit and human papilloma viruses.

ISSN:0300-5526    

DOI:10.1159/000149759

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Epstein-Barr virus (EBV) derived from the B95-8 line has transforming activity for cord blood cells, whereas virus derived from the P3HR-1 line lacks such activity. When the two viral preparations were compared for their ability to infect the same EBV-genome-negative lymphoblastoid cell line, BJA-B, they induced approximately the same number of EBV-determined nuclear antigen (EBNA)-positive cells. EBNA is compatible with continued cell proliferation. No early antigen (EA)-positive cells appeared in the B95-8 virus-infected cultures, whereas P3HR-1 virus-infected cells went on to express EA. EA signals the entry of the cell into the lytic cycle. No late viral antigen (VCA) appeared and, as a consequence, the P3HR-1 virus infection became abortive. In contrast, the EBNA-positive cells induced by the B95–8 virus continued to divide over several weeks. These findings show that different EBV isolates may differ in their biological activity, probably due to their having different degrees of viral dependence on restrictive host cell control

ISSN:0300-5526    

DOI:10.1159/000149760

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

A simple qualitative spot complementation test for the analysis of temperature-sensitive mutants of papovavirus SV40 is described. The procedure is rapid, reproducible over a wide range of virus titers, and applicable to mutants with either low or moderate leak and revertant frequencies. An improved quantitative complementation assay is also described.

ISSN:0300-5526    

DOI:10.1159/000149761

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Twelve isolates of street rabies virus were inoculated intramuscularly into young hamsters and the course of infection was followed by frozen section immunofluorescence. Animals infected with 10 of the 12 viruses had antigen in striated muscle at day 3, but involvement of other tissues was absent or extremely sparse. Muscle infection was still most pronounced at day 6, but neuromuscular spindle, nerve, and brain infections were also detected in a majority of animals. Progression of infection was continuous, with striking terminal accumulations of antigen. The early myotropism of rabies virus may yield the virus which invades the peripheral nervous system, and may represent a phase of infection vulnerable to postexposure intervention.

ISSN:0300-5526    

DOI:10.1159/000149762

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

BALB/c mouse embryo cells morphologically transformed by papovavirus SV40 initially failed to produce tumors in immunocompetent or immunosuppressed syngeneic newborn or adult mice. Prolonged in vitro cultivation was required for the transformed cells to produce tumors in the immunosuppressed host. The level of expression of murine leukemia virus gs antigen in transformed cells did not increase until the transformed cells had undergone four or five in vivo passages suggesting that the malignant property of the transformed cells is expressed independently of the murine leukemia virus gs antigen.

ISSN:0300-5526    

DOI:10.1159/000149763

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Analysis of DNA preparations from bacteriophages T4 and T7 by renaturation kinetics revealed that bacteriophage T7 DNA contained a rapidly reannealing fraction (about 6%) indicative of repeated sequences, whereas bacteriophage T4 DNA reassociated with kinetics typical of a genome composed entirely of unique sequences.

ISSN:0300-5526    

DOI:10.1159/000149764

出版商:S. Karger AG    

年代:1974

数据来源: Karger