摘要:

An Epstein-Barr virus protein associated with the restricted component of the early antigen complex was characterized in this study. This protein was of particular interest because of its homology to polyoma middle T antigen and to the product of the bcl-2 oncogene. The results from this study reveal that this protein had a number of unusual properties in comparison with other polypeptides associated with the early antigen complex. For example, the synthesis of this membrane-associated antigen was regulated by the cell cycle, and its expression was compatible with cell survival. Functional studies reveal that immunoprecipitates containing this protein exhibited a threonine-serine-specific protein kinase activity. The results suggest that this protein might function in both the immortalization and replication cycles of this virus.

ISSN:0300-5526    

DOI:10.1159/000150128

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The addition of tegument or matrix proteins and the outermost membrane to human cytomegalovirus (strain AD 169) replicating in human cells appeared to occur differently in the nucleus than in the cytoplasm. In the nucleus cytomegalovirus was completed structurally within intranuclear sacs, as envelopment at the end of tubular structures, containing an electron-dense material, included tegument and outer membrane simultaneously. In the cytoplasm structural completion occurred in separate steps. Tegument could be added by association with dense bodies; then, interaction with the membranes of vacuoles or vesicles provided the outermost covering. Tubes originating in intranuclear sacs have been described previously only in guinea pig cells infected with guinea pig cytomegalovirus.

ISSN:0300-5526    

DOI:10.1159/000150129

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The luteoviruses barley yellow dwarf virus (BYDV-PAV and BYDV-RPV), bean leaf roll virus (BLRV) beet western yellows virus (BWYV), carrot red leaf virus, potato leaf roll virus, and soybean dwarf virus (SDV) were compared by hybridization with random cDNA probes and serologically with polyclonal antisera. For hybridizations, filters had each RNA blotted in duplicate dots at 10 ng/dot. Random-primed cDNA probes were prepared from 300 ng of each RNA and used to probe filters at three levels of stringency. Homologies were observed between BLRV and SDV and between BWYV and BYDV-RPV at the lowest level of stringency (Tm-38). In double-antibody sandwich enzyme-linked immunosorbent assay using polyclonal antisera, two-way relationships were observed between BWYV and BYDV-RPV. In indirect enzyme-linked immunosorbent assay, where purified virus denatured in pH 9.6 carbonate buffer was coated directly onto microtiter plates, relationships between members of the luteoviruses were much more extensive. BLRV, BWYV, BYDV-PAV, carrot red leaf virus, potato leaf roll virus, and SDV antisera reacted with each of the six luteoviruses tested in the indirect test, while the BYDV-RPV antiserum reacted only with BYDV-RPV, BWYV, and BLRV. BWYV and BYDV-RPV are closely related in both tests and should be considered strains of one virus.

ISSN:0300-5526    

DOI:10.1159/000150130

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Coat protein of raspberry ringspot nepovirus (RRV) migrated during electrophoresis in a discontinuous buffer system as two components which were capable of interchanging during this procedure. However, only one component was formed during electrophoresis in a continuous buffer system. Treatment of the protein before electrophoresis with iodoacetamide, which alkylates sulfhydryl groups, prevented the formation of the faster migrating electrophoretic component. Thus the faster migrating component is probably an artifact caused by S-S bond formation. Although the coat proteins of two other nepoviruses did not behave in this way, the results obtained with RRV emphasize the need for caution in interpreting electrophoretic heterogeneity in virus proteins. The estimated molecular weight of RRV coat protein was 57,000.

ISSN:0300-5526    

DOI:10.1159/000150131

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Serological and physical properties of isolated particles as well as reactions of barley cultivars after virus inoculation showed that the yellow disease of barley is caused by different viruses. Results summarized in this paper suggest that the European isolates BaYMV-So and BaYMV-NM are closely related to, or identical with, BaYMV-J first reported from Japan, whereas BaYMV-M differs in several properties. Therefore, it seems justified to describe BaYMV-M as a separate virus tentatively designated barley mild mosaic virus.

ISSN:0300-5526    

DOI:10.1159/000150132

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Cylindrical inclusion proteins (CIPs), amorphous inclusion proteins (AIPs), and virus particles were partially purified from Cucurbita maxima leaves infected with zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus 2 (WMV2), and the watermelon mosaic virus 1 strain of papaya ringspot virus (PRSV-W). Antisera to these individual antigens, except AIPs of ZYMV and WMV2, were prepared and used to determine with electroblot-ELISA the serological differentiation indices (SDIs) between homologous and heterologous antigens. The average SDIs between ZYMV and WMV2 CIPs, between ZYMV and PRSV-W CIPs, and between WMV2 and PRSV-W CIPs were 1.5, 3.5, and 2.5, respectively. The SDIs between ZYMV and PRSV-W AIPs and between WMV2 and PRSV-W AIPs were 5 and 3, respectively. The average SDIs between ZYMV and WMV2 capsid proteins (CPs), between ZYMV and PRSV-W CPs, and between WMV2 and PRSV-W CPs were 3, 7, and 8, respectively. These data suggest that the serological relationship between ZYMV and WMV2 is much closer than that between PRSV-W and ZYMV or between PRSV-W and WMV2 and that antigenic determinants of CIP and AIP were conserved more than those of CP among the three potyviruses.

ISSN:0300-5526    

DOI:10.1159/000150133

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Viral single-stranded DNA of mung bean yellow mosaic virus (MYMV) was converted to the double-stranded state in vitro, and physical mapping was carried out. The genome of MYMV was found to consist of two major components (designated as DNA 1 and DNA 2). In addition, some minor components were detected. Molecular cloning of the major components was carried out, using in vitro double-stranded DNA and replicative intermediate DNAs. DNA 1 is about 2.72 and DNA 2 about 2.67 kilobase pairs. No similarities were observed when the two restriction maps of DNA 1 and 2 were compared.

ISSN:0300-5526    

DOI:10.1159/000150135

出版商:S. Karger AG    

年代:1990

数据来源: Karger