摘要:

The triple gene block (TGB) of barley stripe mosaic virus (BSMV), coding for viral movement proteins (MPs), was replaced by the single MP gene of red clover necrotic mosaic virus (RCNMV). Accumulation of the hybrid virus in barley plants (the selective host for BSMV) was reduced compared to BSMV. The hybrid virus induced small necrotic local lesions on Chenopodium amaranticolor leaves and did not infect Nicotiana clevelandii (te selective host for RCNMV). The hybrid virus accumulated in the inoculated leaves of Nicotiana benthamiana, but not in the upper noninoculated leaves. Thus the RCNMV MP gene substituted for the BSMV TGB in cell-to-cell movement, but not in systemic spread. Hybrid virus movement was efficient only in N. benthamiana, the common host for BSMV and RCNMV. These data point to the involvement of host-specific factors in the function of virus-coded transport determinants.

ISSN:0300-5526    

DOI:10.1159/000150514

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The effect of protein tyrosine kinase (PTK) inhibitors on the replication of herpes simplex virus (HSV) was examined. Tyrphostins AG17, AG213, AG490, and AG555, and herbimycin A all inhibited the plaque formation of HSV type 1 (HSV-1) in Vero cells, but AG17, AG490, and AG555 exhibited a more selective antiviral effect. In the presence of 0.4 µM AG17, the virus production 24 h after infection was decreased to 7.7% of the untreated control level. Even if the treatment was started 12 h after the initiation of infection, the viral titer was reduced by 82.4%, compared with the untreated control level. In HSV-1-infected cells ICPs 6, 17/18, 19/20, and 25 were tyrosine-phosphorylated proteins. The synthesis and phosphorylation of these proteins were inhibited by AG17, and suppression of ICP 19/20, which were identified as the UL47 gene products, was the greatest. In contrast, the in vitro autophosphorylation of viral proteins was not affected by this PTK inhibitor. These results indicate that tyrphostin may represent a novel class of inhibitors of HSV-1, and that the viral proteins which have phosphorylated tyrosine residues and are suppressed by AG17 most significantly are the products of the UL47 gene, the tegument proteins VP13/14

ISSN:0300-5526    

DOI:10.1159/000150515

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The animal model of necrotic hepatitis caused by HSV-1 infection in juvenile mice was used to compare the efficacies of the oral antiherpes agents famciclovir (FCV), valaciclovir (VACV) and brivudin (BVDU). The experimental infection allows the measurement of viral replication in the liver by macroscopic lesions and the evaluation of mortality from encephalitis. Mice intravenously inoculated with a highly virulent clinical HSV-1 isolate were orally treated by gavage over a period of 3 days starting on day 2 post infection. The reference drug acyclovir (ACV) was administered subcutaneously. Necrotic hepatitis was significantly (p < 0.01) reduced by treatment with FCV, VACV and ACV at a dose of 50 mg/kg per day divided into 3 doses. No significant effect was achieved with BVDU at 200 mg/kg per day. Treatment with FCV at 50 mg/kg per day, ACV at 100 mg/kg per day, and VACV at 200 mg/kg per day significantly (p < 0.001) decreased mortality in mice. BVDU treatment at 200 mg/kg per day did not reduce mortality but significantly prolonged (p < 0.05) the survival time.

ISSN:0300-5526    

DOI:10.1159/000150516

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The genes encoding the envelope glycoprotein H (gH) and gB homologues were identified by sequencing genomic clones of human herpesvirus-7 (HHV-7), strain JI. A gB cDNA clone from HHV-7 strain AL was also identified. The deduced primary translation products of the gH and gB genes are a protein of 690 amino acids, with a predicted mass of 80.4 kD, and a protein of 822 amino acids, with a predicted mass of 93.3 kD, respectively. Both the predicted proteins have the characteristics of transmembrane glycoproteins, containing signal and transmembrane sequence motifs and characterized by the presence of 10 (gH) and 11 (gB) potential motifs for N-glycosylation. Comparison of amino acid sequence of HHV-7 gH and gB with the homologous sequences of the other human herpesviruses reveals closest homology with HHV-6 (38.8% identity for gH, 56.2% identity for the gB). In addition, significant sequence similarity was also observed between the gH and gB of HHV-7 and the homologs encoded by human cytomegalovirus (21.6% identity for gH, 37.6% identity for gB). No significant differences existed between the gB sequence of the two different HHV-7 strains analyzed. The products of the HHV-7 gH and gB expressed transiently in eukaryotic cells were specifically recognized by an HHV-7-reactive human serum in immunofluorescence assays.

ISSN:0300-5526    

DOI:10.1159/000150517

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

L cells persistently infected with strain Armstrong lymphocytic choriomeningitis virus generated a variant which failed to develop the lethal neurologic disease after application to the brain. This virus was able to protect mice from the fatal consequences when inoculated intra-cerebrally prior to challenge with wild-type (wt) virus. After infection of mice with the attenuated variant and thereafter with the wt virus, production of the latter was extraordinarily reduced. As expected, virus elimination was finally achieved by cytotoxic T lymphocytes, whose activation was accelerated. Furthermore, two events seem to play an important part in this enhanced virus reduction. First, from the beginning of the infection with wt virus, neutralizing antibodies could be noticed. The second observation was an excessive production of interferon-α 1 day after the challenge infection

ISSN:0300-5526    

DOI:10.1159/000150518

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Three monoclonal antibodies (MAbs 1051a, 1051b and 1051c) were raised against a surface region (residues 597-686) of the herpes simplex virus type 1 (HSV-1) DNA polymerase (HSV pol), and their epitopes were mapped. The MAbs reacted serotype specifically with the native and denatured HSV pol, as shown by Western blot analysis, immunoprecipitation and immunofluorescence microscopy, indicating their usefulness for biochemical studies and clinical diagnosis of HSV-1 infections. MAb 1051c, displaying the least cross-reactivity with cellular proteins in the Western blot analysis, was successfully utilized not only for coimmunoprecipitation, but also for the analysis and three-dimensional modeling of the cellular sites of HSV pol interaction by confocal laser immunofluorescence microscopy.

ISSN:0300-5526    

DOI:10.1159/000150519

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In Spodoptera frugiperda (SF IPLB-21) cells productively infected with S. frugiperda multicapsid nuclear polyhedrosis virus (SfMNPV), we observed the synthesis of infected-cell-specific polypeptides (ICSPs) using the protein synthesis inhibitor cycloheximide (CX) and the DAN synthesis inhibitor cytosine arabinoside (Ara-C) in an attempt to assess whether a temporal cascade and viral DNA synthesis are involved in the gene expression program of SfMNPV. Inhibition of protein synthesis with CX at 0 h postinfection resulted in the active synthesis of a group of ICSPs immediately after removal of CX, suggesting that these polypeptides, designated α-ICSP, did not require de novo protein synthesis for their production. A second group of ICSPs (designated β-ICSPs), requiring a prior interval of protein synthesis, was detected when CX was added at later times. A third group of ICSPs also needed an interval of ICSP synthesis, but differed from β-ICSPs in that they required a longer interval of protein synthesis. Moreover, the synthesis of most of these ICSPs also required DNA synthesis, which was demonstrated by addition of Ara-C before and after viral DNA replication; these ICSPs were therefore designated γ-ICSPs. In conclusion, two kinds of regulatory proesses are involved in SfMNPV infection: the first process controls the sequential synthesis of the three ICSP groups, that is α→β→γ; a second process represses the synthesis of ICSP groups, first of the α-ICSPs and subsequently of β-ICSPs. Thus, we propose temporally regulated as well as negative control circuits in SfMNPV gen

ISSN:0300-5526    

DOI:10.1159/000150520

出版商:S. Karger AG    

年代:1997

数据来源: Karger