摘要:

Recurrence rates of genital infections are significantly higher for heφes simplex virus (HSV) type 2 than HSV type 1. Reasons for this difference are not known. In this report, multiple strains of HSV-1 and HSV-2 were evaluated in the guinea-pig model. HSV-2 strains showed significantly higher genital lesion recurrence than HSV-1, including HSV-1 McKrae strain which is highly recurrent in ocular infections. HSV-2 strains were also associated with more frequent asymptomatic vaginal virus shedding. Further study showed that HSV-1 strains replicated as well as HSV-2 in both the genital tract and the nervous system during acute infection. In addition, no difference was detected between HSV-1 and HSV-2 in nervous system latency. Thus, a number of possible explanations for the observed difference in genital heφes recurrence rates were examined and exclude

ISSN:0300-5526    

DOI:10.1159/000150279

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Twenty AV4 isolates were analysed with 18 restriction endonucleases. They could be classified into two genome types (genomic clusters) AV4p and AV4a. Combined with data from Li and Wadell [Arch Virol 1988; 101:65–77], DNA variants p1–p8 and a1–a3 were defined. The genetic relatedness within the genome types was in the range of 88–99% comigrating fragments, whereas < 62% of the fragments were comigrating between the genom

ISSN:0300-5526    

DOI:10.1159/000150280

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

We describe a membrane-filter-based urea-arginine phosphate buffer method for concentrating waterborne viruses from large volumes of water to microlitre volumes, and their subsequent detection by the polymerase chain reaction (PCR). The detection step involves the extraction of RNA, synthesis of complementary DNA, amplification by PCR of target DNA with specific primers, and confirmation through nucleic acid hybridization with a radiolabelled oligonucleotide probe. The PCR technique detected the presence of enteroviruses in spiked as well as in contaminated water samples. The technique is sensitive and detects as few as 120 waterborne viral particles. PCR is simple, rapid, sensitive, specific and adaptable for water quality surveillance in less developed countries.

ISSN:0300-5526    

DOI:10.1159/000150281

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Antibodies to Epstein-Barr-virus-specific DNase in children under 15 years old from Taipei, Taiwan were determined by an enzyme neutralization test. Serum was taken as positive for the anti-DNase antibody when 1 ml of serum could neutralize > 2 units of the DNase activity. Among the 1,292 sera tested, 5.6% of the children were shown to have anti-EBV DNase antibodies, a result similar to that for adults. Maternal antibodies against the EBV DNase were found to decrease very rapidly 2 months after the child’s birth, and new antibody appeared upon natural EBV infectio

ISSN:0300-5526    

DOI:10.1159/000150282

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Strains of infectious pancreatic necrosis virus (IPNV-Jasper) obtained from two different laboratories were compared serologically with polyclonal and monoclonal antibodies. Nucleotide sequence and restriction endonuclease patterns of 359-bp fragment of genome segment A cDNA were also compared. Substantial differences were found in both analyses that will support the fact that the two Jasper strains are not identical.

ISSN:0300-5526    

DOI:10.1159/000150283

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Transmission of human T cell leukemia virus type I (HTLV-I) to a T cell line (MOLT-4#8) was studied using cell-free virus infection or cocultivation with an HTLV-I-transformed T cell line (MT-2). Immunofluorescence and FACS analyses showed that HTLV-I was efficiently adsorbed onto MOLT-4#8 cells. However, after adsorption, no extrachromosomal viral DNA in the cells was detected by the Southern blot method. In contrast, when MT-2 cells were cocultured with MOLT-4 # 8 cells, generation of extrachromosomal DNA was clearly observed. These data suggest that the cell-free HTLV-I may have difficulties in penetration, uncoating or reverse transcription. After cocultivation, MOLT-4 # 8 cells chronically infected with HTLV-I were cloned and analyzed. Only four provirus-positive cell lines were obtained. The transmission rate of the virus by cocultivation seemed to be low in our experimental system, although marked cell fusion was observed. Moreover, none of the cloned cell lines which harbored HTLV-I provirus expressed any viral protein. Inefficient integration and expression of the provirus might be hypothesized as compared with human immunodeficiency virus type 1 transmission.

ISSN:0300-5526    

DOI:10.1159/000150284

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Bacterial luciferase, derived from a fusion of the lux A and luxB genes of Vibrio harveyi, has been expressed at very high levels in caterpillars and insect cells. The coding sequence for luciferase was inserted into vectors developed in our laboratory which were designed to expedite screening of recombinant virus. These vectors contained the β-galactosidase indicator gene under control of immediate early (IE1), early (ETL), or very late (P10) promoters and a cloning site for inserting the fused luciferase gene next to the polyhedrin promoter. Recombinant baculo-viruses containing the luciferase gene as well as the β-galactosidase gene could be easily selected when Bluogal (β-galactosidase indicator) was included in the plaque assays. Using cells derived from the fall armyworm (Spodopterafrugiperdä), luciferase was strongly expressed very late in infection (48–72 h). The bacterial luciferase assay was sufficiently sensitive that light production could be detected from an extract of a single cell. In addition, live insects, including the cabbage looper (Trichoplusia ni) and saltmarsh caterpillar (Estigmene acred) were infected by mixing recombinant baculovirus into their diet. Cabbage loopers (with an average wet weight of 223 mg) produced at least 195 µg of active luciferase and levels of synthesis peaked between 96–120 h. The results indicate that bacterial luciferase may be used as a reporter of gene expression in

ISSN:0300-5526    

DOI:10.1159/000150285

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150286

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150287

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150278

出版商:S. Karger AG    

年代:1992

数据来源: Karger