ISSN:0300-5526    

DOI:10.1159/000149248

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The production and release of R-type virus-like particles (VLP) was studied in several Syrian hamster cell lines. Most but not all hamster cell lines contain detectable levels of R-type VLP. However, only BHK-21 clone F (CF) cells would release the VLP into culture fluids. Treatment with dexamethasone enhanced to a limited extent the production and release of VLP from BHK-21 CF cells. Actinomycin D inhibited the production and release of R-type VLP in hamster cells, suggesting that some transcription from DNA is necessary for VLP production. Furthermore, 5-iododeoxyuridine induced the production of R-type VLP in Syrian hamster embryo cells. These results suggest that R-type VLP are endogenous to Syrian hamsters.

ISSN:0300-5526    

DOI:10.1159/000149249

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The baculovirus, Heliothis zea nuclear polyhedrosis virus (HzSNPV), was grown in the H. zea cell line, IPLB-1075. Light microscopy observations showed that 95% of inoculated cells had CPE by 6 days postinoculation (p.i.). Growth curves of intracellular and extracellular virus showed that maximum titers (TCID50 units) were reached 3–4 days p.i. Studies on HzSNPV morphogenesis revealed that ultrastructural events were typical of baculovirus replication in vitro. EcoRI restriction enzyme analyses of viral DNA produced in larvae and in cell culture were identical and indicated that this virus was HzSNP

ISSN:0300-5526    

DOI:10.1159/000149250

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Infection of cultured human skin fibroblasts by herpes simplex virus leads to increased incorporation of labeled inorganic phosphate into host membrane sphingomyelin. Incorporation into the other major membrane phospholipids, including phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, was unaffected. Since sphingomyelin has been shown to serve as precursor to ceramides (via sphingomyelinase) in monkey kidney cells and since enhanced synthesis of ceramide-based glycolipids has been shown to occur after herpes simplex virus infection, we suggest that the observed increase in labeling of sphingomyelin may reflect mobilization for glycolipid synthesis. The distribution of phosphate label among the phospholipids of the viral envelope was identical to that among the phospholipids of the cellular cytoplasmic membrane fraction and differed from that of the nuclear fraction.

ISSN:0300-5526    

DOI:10.1159/000149251

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Five plant rhabdoviruses fall into two groups based on the patterns produced by their dissociated virion proteins when separated electrophoretically. Lettuce necrotic yellows virus (LNYV) and Sonchus virus (SV) virions contained only one M protein and NS protein. Sowthistle yellow vein virus (SYVV), Sonchus yellow net virus (SYNV) and eggplant mottled dwarf virus (EMDV) virions contained two M proteins and no detectable NS protein. The M and G proteins of LNYV and SV were easily released from the nucleocapsid after incubation with 1 % Nonidet P40 (NP40), whereas the G protein and only a proportion of one of the M proteins were released from the nucleocapsids of SYVV, SYNV and EMDV after incubation with 1% NP40. It was necessary to increase the NP40 concentration to 4% to release both M proteins from SYVV nucleocapsids.

ISSN:0300-5526    

DOI:10.1159/000149252

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The intracellular fate of 3H-labeled exogenous herpes simplex virus type 2 DNA following the exposure of recipient cells to selected DNA facilitators and the ultrastructural changes which ensued in transfected cultures were examined. In most cases, electron microscopic radioautography demonstrated that exogenous DNA reached the nucleus within 1 h postinoculation. At later time periods, enlargement of nuclei and margination of chromatin were noted. Cells treated with polyornithine differed significantly from those treated with other facilitators in that large cytoplasmic accumulations of labeled material associated with electron-dense, membrane-bound bodies persisted after 1 h postinoculation. In contrast, labeled DNA released by intact virions was detected in the nucleus as early as 20 min postinfection (p.i.), and progeny virus was evident by 8 h p.i. These results suggest that the efficiency of each facilitator is related to the rapidity with which exogenous DNA penetrates the recipient cell, traverses the cytoplasm, and the amount of DNA which is finally associated with the nuclear compartment.

ISSN:0300-5526    

DOI:10.1159/000149253

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The induction kinetics of the antiviral state in HeLa cells treated with human lymphoblastoid interferon (IFN) was studied. In cells treated with 4–200 U/ml IFN, the antiviral state was fully established in 7–9 h. Inhibition of virus multiplication was more rapid if the concentration of IFN was increased to 1,000 U/ml. This antiviral state gradually disappeared during the 48 h after IFN removal. Several compounds known to act on the cell membrane or on the cytoskeleton were tested for their influence on the establishment and reversal of the antiviral state. None of them were found to influence these two parameters to a significant extent. In contrast, placing HeLa cells in medium lacking NaCl partially reversed the blockade to virus multiplication induced by IFN treatment. Cells treated with IFN and later placed in hypotonic medium synthesized virus proteins after encephalomyocarditis virus infection, although at a reduced level compared to cells that had not been treated with

ISSN:0300-5526    

DOI:10.1159/000149254

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

F1 hybrid mice, resulting from a cross between a susceptible and a resistant parent, were infected with a cloned substrain of mouse hepatitis virus type 3 (MHV3). Results showed various evolutive patterns ranging from fulminant hepatitis to persistent infection and excluded virus variation as an explanation for different disease types. Since host resistance to MHV3 has been previously shown to be under the genetic influence of 1 or 2 genes only rather than a polygenic phenomenon, these results strongly suggest that nongenetic factors play a major role in the determination of evolutive patterns.

ISSN:0300-5526    

DOI:10.1159/000149255

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Nuclear antigen (EBNA) inducibility by Epstein-Barr virus (EBV) was assessed in relation to the presence of complement (C3) receptors and surface immunoglobulins (SIg) on leukemic lymphocytes. When erythrocyte-antibody-complement complex(EAC)-positive, SIg-negative B cells were exposed to EBV, EBNA synthesis occurred with a high frequency. In contrast, no significant EBNA induction was evident in SIg-positive, EAC-negative B cells. Cells possessing both markers were EBV-infectable, in proportion to the frequency of EAC-rosette formation. These data seem to indicate that EBV susceptibility of human B cells is closely related to the presence of C3 receptors but not SIg. Leukemic T cells and myelogenous leukemia cells were not EBV-susceptible, although some cells were significantly positive for C3 receptors.

ISSN:0300-5526    

DOI:10.1159/000149256

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Nuclear involvement of the host cell in Junin virus (JV) replication was studied. α-Amanitin was shown to inhibit JV yield, and RNA synthesis in cell nuclei was found to be augmented during the eclipse period. JV infection exerted a selective effect on cellular RNA polymerase activities, when measured in purified infected nuclei. RNA polymerase I was inhibited, but RNA polymerase II was stimulated. These data support the hypothesis that RNA polymerase II is involved in arenavirus replication

ISSN:0300-5526    

DOI:10.1159/000149257

出版商:S. Karger AG    

年代:1981

数据来源: Karger