摘要:

The simian sarcoma virus type 1 (SSV-1) and its associated virus (SSAV-1), C-type RNA viruses, were found to possess a 60 to 70S RNA and a RNA-dependent DNA polymerase. Endogenous enzyme activity requires magnesium and is inhibited by ribonuclease. The enzyme utilizes the 60 to 70S RNA as a template and the product of this enzyme consists of DNA, as shown by physical and chemical methods. The product DNA specifically hybridizes to the SSV-1/SSAV-1 60 to 70S RNA.

ISSN:0300-5526    

DOI:10.1159/000148851

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The relationship between the position of chick embryo fibroblasts in the mitotic cycle and their susceptibility to infection by B-RSV (RAVI) was studied in synchronized cultures. The pattern of virus growth was similar in cultures infected at various times during the mitotic cycle. Notably, first virions were released after comparable delays in cultures infected before, during or after the S phase, and the virus production was identical when measured up to 48 h after infection. Latent periods extended from 8 to 15 h according to the experiment. Identical results were obtained with both calf sera used to induce mitoses. These results show that the S phase of cellular DNA synthesis is not required at some early stage of the viral cycle and suggest that there is no obligatory relationship between RSV production and the cell cycle.

ISSN:0300-5526    

DOI:10.1159/000148852

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Chick embryo fibroblasts synchronized in two different ways were infected at various times in the cell cycle with B-RSV (RAVI) in the presence of a particular calf serum. In all experiments, with both methods of synchronization, the length of the latent period depended on when cells were infected in the cell cycle. In cultures infected in the G1 and S phases, the production of the virus was delayed until the phase G2 or after the cell division, depending on what method was used to synchronize cells. In cultures infected after the G2 phase, the production of the virus was delayed until after cell division. It is concluded that cell event(s) are required at some stage of the infection for it to be successful; they can occur in a synchronous manner in the G2 phase, before replication of the mitochondrial DNA, and after the wave of mitoses when some component(s) are present in the calf serum used to induce the cell division.

ISSN:0300-5526    

DOI:10.1159/000148853

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Inactivation of Semliki Forest virus (SFV) with formalin, β-propiolactone, hydroxylamine and 2-ethyl ethylenimine was studied. Immunogenicity of SFV was best retained after formalin inactivation. Vaccines were pre pared by applying two inactivation procedures in the following order: (a) disruption of SFV by either Tween 80- ether, NP 40 or deoxycholate, or treatment of SFV with saponin; (b) addition of either formalin, β-propiolactone, hydroxylamine or 2-ethylethylenimine. These vaccines were evaluated in white mice, in several experiments. It was concluded that a gradient from potent to less- or non-potent vaccines exists in the order saponin-formalin, Tween 80-ether-formalin and NP 40-ethylethylenimine or deoxycholate-formalin inactivation, but none of these vaccines was superior to reference vaccines containing only formalin-inactivated viru

ISSN:0300-5526    

DOI:10.1159/000148854

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Double inactivated vaccines were prepared with formalin-inactivated Semliki Forest virus subsequently treated with Tween 80-tri(n-butyl)phosphate, with saponin, or with a combination of both. These vaccines possessed a similar or even higher protective potency when compared with vaccines containing untreated formalin-inactivated virus. A considerable part of the formalin-inactivated virions are not disrupted by Tween 80-TNBP treatment in spite of the release of lipid components resulting in a higher buoyant density of the virions; in these particles, virus RNA is accessible to RNase.

ISSN:0300-5526    

DOI:10.1159/000148855

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A heat-labile inhibitor (HLI) capable of neutralizing the infectivity of variola virus, as measured by reduction of focus-forming and plaque-forming activity, was detected in normal human, guinea pig, rabbit and monkey sera. HLI lost its activity on incubation at 56° for 30 min, and showed different behaviors from complement in heat inactivation curves as well as in specific absorption with variola virions. HLI is suggested to be of globulin nature on the basis of sensitivity to trypsin digestion and reaction with fluorescent antibody against guinea pig serum γ-globulin, as determined by staining HLI-saturated virions. HLI was equally active for variola (major and minor), vaccinia and Newcastle disease viruses, but inactive for herpes simplex and Japanese encephalitis viruse

ISSN:0300-5526    

DOI:10.1159/000148856

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Characterization of the heat-labile variola virus inhibitor (HLI) present in normal hu man and guinea pig serum (GPS) was attempted. The HLI activity was destroyed by 2-mercaptoethanol, acetone, dialysis against acid and UV-irradiation, but was resistant to oxidation with KIO4. Sucrose density gradient centrifugation of GPS located the HLI activity in fractions sedimenting faster than IgM, whereas the complement activity was found in the slower sedimenting IgG + IgA region. The serum fraction containing HLI, obtained by sucrose density gradient centrifugation, did not enhance neutralization by an early antiserum, whereas the complement fraction did. The HLI activity of the above isolated fraction was far more sensitive to trypsin than that of the whole serum. Infectivity of HLI-neutralized variola virions was restored by short digestion with 0.01 % trypsin, while sonication had no such effect. Neutralization with HLI did not inhibit virus adsorption to cells but blocked the induction of early soluble antigen (s-antigen).

ISSN:0300-5526    

DOI:10.1159/000148857

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Thin section electron microscopic examination of several viruses of the Bunyamwera serologic supergroup of arbo viruses confirmed their precise similarities in morphology and morphogenesis and their differences from viruses of other groups. Several viruses that are serologically unrelated to the supergroup were indistinguishable from Bunyamwera virus when observed in the same way. A separate taxonomic group or ‘family’, ultimately to be based upon multiple common physicochemical virion properties, is proposed to encompass the more than 130 viruses listed; the name Bunyaviridae is proposed for this ta

ISSN:0300-5526    

DOI:10.1159/000148858

出版商:S. Karger AG    

年代:1973

数据来源: Karger