141.
Comparison of Membrane Protein Glycopeptides of Sindbis Virus and Vesicular Stomatitis Virus
- Burge, Boyce W.; Huang, Alice S.
A comparison has been made of the membrane glycoproteins and glycopeptides from two enveloped viruses, Sindbis virus and vesicular stomatitis virus (VSV). Glycopeptides isolated from Sindbis virus and VSV grown in the same host appear to differ principally in the number of sialic acid residues per glycopeptide; when sialic acid is removed by mild acid treatment, the glycopeptides of the two viral proteins are indistinguishable by exclusion chromatography. Preliminary evidence argues that the carbohydrate moiety covalently bound to different virus-specified membrane proteins may be specified principally by the host.
142.
Colorado Tick Fever Virus: Growth in a Mosquito Cell Line
- Yunker, C. E.; Cory, J.
Two strains of Colorado tick fever virus grew in Singh's Aedes albopictus cells. In one of three experiments, virus growth continued for 7 weeks.
143.
Nucleotide Composition of the Ribonucleic Acid of Rabies Virus
- Aaslestad, H. G.; Urbano, Charlotte
The nucleotide composition of the ribonucleic acid of three strains of rabies virus was determined and found to be similar to that of vesicular stomatitis virus.
144.
Colorado Tick Fever Virus: Growth in a Mosquito Cell Line
- Yunker, C. E.; Cory, J.
Two strains of Colorado tick fever virus grew in Singh's Aedes albopictus cells. In one of three experiments, virus growth continued for 7 weeks.
145.
Nucleotide Composition of the Ribonucleic Acid of Rabies Virus
- Aaslestad, H. G.; Urbano, Charlotte
The nucleotide composition of the ribonucleic acid of three strains of rabies virus was determined and found to be similar to that of vesicular stomatitis virus.
146.
Primary Virus-Cell Interactions in the Immuno-fluorescence Assay of Venezuelan Equine Encephalomyelitis Virus
- Hahon, Nicholas; Cooke, Kenneth O.
The conditions under which Venezuelan equine encephalomyelitis (VEE) virus attached to host cells markedly influenced the assay of virus by the fluorescent cell-counting technique. When virus inoculum was centrifuged onto McCoy cell monolayers, approximately 97% of virus was attached to cells within 10 min, in contrast to 34% after stationary incubation at 35 C for 2 hr. Maximal binding of virus occurred only in the presence of 0.1 to 0.15 m NaCl. This salt requirement, added to evidence of pH dependence and temperature independence of VEE virus attachment to cells, indicated that the initial union involved electrostatic forces. Virus penetration,...
147.
Primary Virus-Cell Interactions in the Immuno-fluorescence Assay of Venezuelan Equine Encephalomyelitis Virus
- Hahon, Nicholas; Cooke, Kenneth O.
The conditions under which Venezuelan equine encephalomyelitis (VEE) virus attached to host cells markedly influenced the assay of virus by the fluorescent cell-counting technique. When virus inoculum was centrifuged onto McCoy cell monolayers, approximately 97% of virus was attached to cells within 10 min, in contrast to 34% after stationary incubation at 35 C for 2 hr. Maximal binding of virus occurred only in the presence of 0.1 to 0.15 m NaCl. This salt requirement, added to evidence of pH dependence and temperature independence of VEE virus attachment to cells, indicated that the initial union involved electrostatic forces. Virus penetration,...
148.
Inhibition of Virus Release by Antibodies to Surface Antigens of Influenza Viruses
- Dowdle, W. R.; Downie, J. C.; Laver, W. G.
When influenza virus was mixed with antisera to its surface subunits before inoculation of cell cultures, anti-hemagglutinin antibodies neutralized infectivity but anti-neuraminidase did not. When the antisera were added after infection of cell cultures, anti-hemagglutinin and anti-neuraminidase antibodies were equally effective in reducing virus titers in culture fluids. Decreased virus titers were not due to interference of antibody with assay and were not accompanied by a reduction in the synthesis of hemagglutinin and neuraminidase subunits. Both antisera also effectively prevented in vitro virus spread. Inhibition of virus release by neuraminidase antibody appeared unrelated to its antienzyme property. Hydrolysis of N-acetyl...
149.
Inhibition of Virus Release by Antibodies to Surface Antigens of Influenza Viruses
- Dowdle, W. R.; Downie, J. C.; Laver, W. G.
When influenza virus was mixed with antisera to its surface subunits before inoculation of cell cultures, anti-hemagglutinin antibodies neutralized infectivity but anti-neuraminidase did not. When the antisera were added after infection of cell cultures, anti-hemagglutinin and anti-neuraminidase antibodies were equally effective in reducing virus titers in culture fluids. Decreased virus titers were not due to interference of antibody with assay and were not accompanied by a reduction in the synthesis of hemagglutinin and neuraminidase subunits. Both antisera also effectively prevented in vitro virus spread. Inhibition of virus release by neuraminidase antibody appeared unrelated to its antienzyme property. Hydrolysis of N-acetyl...
150.
Newcastle Disease Virus Infection of L Cells
- Hecht, Toby T.; Summers, Donald F.
Newcastle disease virus (NDV) California strain reportedly grows poorly in L cells but replicates very well in chicken embryo cells. NDV-infected L cell cultures show a characteristic virus growth curve with respect to uridine incorporation, but plaque assays of the virus produced 24 h postinfection (PI) show no infectious particles when assayed on L cell monolayers and only a very low titer on chick cell monolayers. Plasma membranes isolated and purified from infected L cells 8 h PI contain all of the major virion proteins. In addition, NDV-infected L cells show a 50% loss of H-2 antigenic activity, a phenomenon...
151.
Newcastle Disease Virus Infection of L Cells
- Hecht, Toby T.; Summers, Donald F.
Newcastle disease virus (NDV) California strain reportedly grows poorly in L cells but replicates very well in chicken embryo cells. NDV-infected L cell cultures show a characteristic virus growth curve with respect to uridine incorporation, but plaque assays of the virus produced 24 h postinfection (PI) show no infectious particles when assayed on L cell monolayers and only a very low titer on chick cell monolayers. Plasma membranes isolated and purified from infected L cells 8 h PI contain all of the major virion proteins. In addition, NDV-infected L cells show a 50% loss of H-2 antigenic activity, a phenomenon...
152.
ASAT: Uma ferramenta para detecção de novos vírus
- Eduardo Mazza Batista
O termo vírus de computador pode ser utilizado para definir de maneira geral qualquer programa que possua intenções maliciosas. É de interesse que, desde grandes empresas até usuários domésticos, exista proteção contra tais ameaças virtuais. A informação atualmente é vista como um bem muito valioso e de total importãncia. Existem vários casos de prejuízos causados devido a danos em informação confidenciais de empresas. Os ataques de vírus visam prejudicar de alguma forma esse patrimônio, seja danificando-o, por remoção ou alteração, ou até mesmo roubando-o e em alguns casos seqüestrando-o. Diversas medidas de segurança podem ser adotadas com o objetivo de...
153.
Growth of Pseudotypes of Vesicular Stomatitis Virus with N-Tropic Murine Leukemia Virus Coats in Cells Resistant to N-Tropic Viruses
- Huang, Alice S.; Besmer, Peter; Chu, Louise; Baltimore, David
Formation of pseudotypes between murine RNA tumor viruses and vesicular stomatitis virus (VSV) has been confirmed. Pseudotypes of VSV genomes coated by the surface envelope from an N-tropic tumor virus grew equally well in cells homozygous for either the Fv-1n or Fv-1b alleles. Therefore, the product of the Fv-1 locus, which restricts growth of murine RNA tumor viruses, must act on an intracellular aspect of tumor virus replication, a step after attachment and penetration.
154.
Growth of Pseudotypes of Vesicular Stomatitis Virus with N-Tropic Murine Leukemia Virus Coats in Cells Resistant to N-Tropic Viruses
- Huang, Alice S.; Besmer, Peter; Chu, Louise; Baltimore, David
Formation of pseudotypes between murine RNA tumor viruses and vesicular stomatitis virus (VSV) has been confirmed. Pseudotypes of VSV genomes coated by the surface envelope from an N-tropic tumor virus grew equally well in cells homozygous for either the Fv-1n or Fv-1b alleles. Therefore, the product of the Fv-1 locus, which restricts growth of murine RNA tumor viruses, must act on an intracellular aspect of tumor virus replication, a step after attachment and penetration.
155.
Structural Characteristics and Nucleotide Sequence Analysis of Genomic RNA from RD-114 Virus and Feline RNA Tumor Viruses
- East, James L.; Knesek, John E.; Allen, Patton T.; Dmochowski, Leon
The results of molecular hybridization experiments have demonstrated that the RNA genome of RD-114 virus has extensive nucleotide sequence homology with the RNA genome of Crandell virus, an endogenous type C virus of cats, but only limited homology with the RNA genomes of feline sarcoma virus and feline leukemia virus. The genomic RNAs of RD-114 virus and Crandell virus also had identical sedimentation coefficients of 50S. A structural rearrangement of genomic RNA did not exist within released RD-114 virions, whereas a structural rearrangement of genomic RNA did occur within feline sarcoma virions and feline leukemia virions after release from virus-producing...
156.
Structural Characteristics and Nucleotide Sequence Analysis of Genomic RNA from RD-114 Virus and Feline RNA Tumor Viruses
- East, James L.; Knesek, John E.; Allen, Patton T.; Dmochowski, Leon
The results of molecular hybridization experiments have demonstrated that the RNA genome of RD-114 virus has extensive nucleotide sequence homology with the RNA genome of Crandell virus, an endogenous type C virus of cats, but only limited homology with the RNA genomes of feline sarcoma virus and feline leukemia virus. The genomic RNAs of RD-114 virus and Crandell virus also had identical sedimentation coefficients of 50S. A structural rearrangement of genomic RNA did not exist within released RD-114 virions, whereas a structural rearrangement of genomic RNA did occur within feline sarcoma virions and feline leukemia virions after release from virus-producing...
157.
Polypeptide Composition of Influenza B Viruses and Enzymes Associated with the Purified Virus Particles
- Oxford, J. S.
Influenza B/LEE/40, B/Rome/1/67, B/Hong Kong/8/73, and B/Victoria/98926/70 viruses have a similar polypeptide composition as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These viruses are composed of six or seven polypeptides, depending on whether one or two high-molecular-weight polypeptides are resolved, ranging in molecular weights from 27,000 to 90,400. Three of these polypeptides, namely the heavy and light hemagglutinin chains and the neuraminidase, have attached carbohydrate. Highly purified influenza B/LEE/40 and B/Rome/1/67 virus preparations have RNA-dependent RNA polymerase activity equivalent to the incorporation of 100 and 30 pmol, respectively, of 3H-UMP per mg of virus protein per h at 37...
158.
Polypeptide Composition of Influenza B Viruses and Enzymes Associated with the Purified Virus Particles
- Oxford, J. S.
Influenza B/LEE/40, B/Rome/1/67, B/Hong Kong/8/73, and B/Victoria/98926/70 viruses have a similar polypeptide composition as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These viruses are composed of six or seven polypeptides, depending on whether one or two high-molecular-weight polypeptides are resolved, ranging in molecular weights from 27,000 to 90,400. Three of these polypeptides, namely the heavy and light hemagglutinin chains and the neuraminidase, have attached carbohydrate. Highly purified influenza B/LEE/40 and B/Rome/1/67 virus preparations have RNA-dependent RNA polymerase activity equivalent to the incorporation of 100 and 30 pmol, respectively, of 3H-UMP per mg of virus protein per h at 37...
159.
Outer Membrane of Avian Myeloblastosis Virus
- Ishizaki, Ryotaro; Luftig, Ronald B.; Bolognesi, Dani P.
Guinea pigs immunized intracerebrally with avian myeloblastosis virus (AMV) produced antiserum which reacted with intact virus particles in complement fixation. The antigen in question appeared to be located on the surface of the virion and could be distinguished from the type-specific virus envelope and the group-specific internal antigens of chicken leukosis-sarcoma viruses (ChiLSV). The material could be isolated by sequential treatments of AMV with bromelin, Tween 20, and freeze-thawing, and could be purified by differential centrifugation. Electron microscopy analysis indicated the presence of a component resembling the outer membrane of the particle. The antigenic determinant was designated virus membrane antigen...
160.
Characteristics of a Virus Isolated from a Feline Fibrosarcoma
- McKissick, G. E.; Lamont, P. H.
A virus was isolated from a radioresistant feline fibrosarcoma. It induced multi-nucleated giant-cell formation and lysis in a cell line derived from a canine fibro-sarcoma, which was used to characterize the virus. End-point titrations in these cells required 28 days. The virus was sensitive to ether and heat and was destroyed at pH 3. Replication was not inhibited by 5-bromodeoxyuridine. Electron microscopy revealed assembly by a budding process from the plasma membrane of infected cells. The average diameter of the virion was 106 nm. Intracisternal particles with an average diameter of 45 nm were present within infected cells. In two...
