ISSN:0300-5526    

DOI:10.1159/000149133

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Electron microscopic examination of a Burkitt’s-lymphoma-derived cell line, P3HR-1, repeatedly revealed clusters of membrane-free nucleoids within the cytoplasmic matrix. The particles possessed an electron-lucent center surrounded by two layers – a dense ring and a fuzzy broad outer la

ISSN:0300-5526    

DOI:10.1159/000149134

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Virus isolation attempts in specific-pathogen-free suckling mice (strain ICR) yielded 21 virus strains initially shown to be closely related to or identical with Tettnang virus. Subsequent studies showed them, as well as standard strains of Tettnang virus, to be closely related to or identical with mouse hepatitis virus. Tettnang virus is not an arbovirus.

ISSN:0300-5526    

DOI:10.1159/000149135

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Purified Junin virus was disrupted by nonionic detergent treatment (Triton X-100), and subviral components were separated by ultracentrifugation. Only the soluble fraction, containing all of the major glycoprotein (mol.wt. 38,000), induced the formation of neutralizing antibodies in laboratory animals and protected them against subsequent challenge with live virus. Thus, the glycoprotein is the antigen responsible for these immunologic responses.

ISSN:0300-5526    

DOI:10.1159/000149136

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Multiple rounds of infection in vitro or in vivo with avian adenovirus-associated virus (AvA-AV) and avian adenovirus (AvAV) result in production of both heavy (H) and light (L) infectious forms. In this study, the infectious AvA-AV progeny produced at different hours during recombined dual infection of cells with either H or L AvA-AV and AvAV was determined by equilibrium CsCl centrifugation and infectivity assay. In both types of infection, H virions were found early, both intra- and extracellularly, whereas L virions were found late. The data indicate an H to L particle density shift during infection. Virus-specified cell-dependent factors mediated the process extracellularly, as activity was detected in infected cell-conditioned medium and in lysates of infected cells but not in medium or components of uninfected cells. The shift in density was accompanied by a conversion in particle type. H and L virions differed in size and conformation as evidenced by differences in serological cross-reactivity and physical-chemical stability during heat inactivation, ultrasonic disruption and DNA extraction.

ISSN:0300-5526    

DOI:10.1159/000149137

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Temperature-sensitive mutants of human rhinovirus type 2 were isolated by random clonings of mutagenized virus. All mutants were stable. Temperature sensitivity was not affected by different host cell systems. Complementation was observed in 3 of 10 dual viral mixtures, with complementation indices being as high as 4.0. Recombination frequencies fluctuated widely between experiments with different mutants, but positive recombination occurred with mean frequencies ranging from 0.03 to 1.25%. The complementation and recombination results obtained are similar to those reported for other picornaviruses.

ISSN:0300-5526    

DOI:10.1159/000149138

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

A temperature-sensitive mutant of adenovirus type 2 grown at 39° (tsl-39°) produces noninfectious physical particles. DNA and core structures derived from such virion particles, however, were found to be infectious at the permissive temperature. Calcium chloride mediated transfection showed that core structures were 20–40 times more infectious than deproteinized DNA. Because in vivo the noninfectious tsl-39° virions are blocked in uncoating at the core-like stage, we attempted to determine the reason for the infectivity of tsl-39° cores prepared in vitro by investigating the metabolic fate of labeled cores in transfected cells. As opposed to infection with virus, the tsl-39° cores were found to penetrate the nucleus efficiently and uncoat by shedding their core proteins. A possible explanation for the infectivity of the cores is dis

ISSN:0300-5526    

DOI:10.1159/000149139

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Ultrastructural study of MRC-5 cells infected by herpes simplex virus yielded several examples of physical continuity between the outer nuclear membrane and the envelope of viral particles in the perinuclear cisterna, suggesting a fusion between the two. Such virions would thus lose their envelope and enter the cytoplasm as naked capsids. Fusion first occurred at 6–8 h postinfection (p.i.), while naked cytoplasmic capsids appeared at 6 h p.i. Since nuclear membrane disruption was not observed until 24 h p.i., it is unlikely to account for the early appearance of these capsids. Thus, in addition to its other roles, the outer nuclear membrane may be involved in naked cytoplasmic capsid production via a fusion even

ISSN:0300-5526    

DOI:10.1159/000149140

出版商:S. Karger AG    

年代:1980

数据来源: Karger