Showing papers in "Virology in 1972"

TL;DR: It is concluded that the formation of lysogens, thermal induction of l Lysogen, production of transducing particles, and spontaneous curing of lYSogens are processes for which the bacterial Rec function is not essential.

TL;DR: The results suggest that in this paramyxovirus both hemagglutinating and neuraminidase activities reside on a single glycoprotein, while the biological function of the smaller SV5 glycop protein remains to be determined.

TL;DR: A model is proposed in which the genes for tet R are inserted into the intact P22 genome in the P22 Tc-10 prophage, and the consequences of such an insertion are discussed with regard to the structure of phage P22 DNA and the topological requirements for successful DNA replication, phage growth, and lysogenization.

TL;DR: All of the infected cell specific polypeptides with the exception of the haemagglutinin components were translated from monocistronic messenger RNA molecules.

TL;DR: The degradation of reovirions by chymotrypsin was affected by the ionic strength of the suspending medium, and strongly influenced by virus concentration, suggesting that particle-particle interactions may play a role.

TL;DR: A series of four-point crosses was devised and carried out in such a way that the progeny of single mixedly infected cells in which recombination events had taken place could be analyzed.

TL;DR: The available evidence suggests that this protein is the carbohydrate-free polypeptide chain of the glycoprotein precursor of the hemagglutinin and that it accumulates in infected cells when glycosylation is blocked.

TL;DR: A kinetic analysis of the amounts of gene products indicated that the synthesis of individual late proteins in phage λ seems to be initiated in an orderly fashion, related to the distance of the genes from the late main promoter between genes Q and S, and indicates the presence of a remarkable control mechanism for gene expression of the left arm.

TL;DR: Hydrolases contained within the lysosomal compartment digest the outer layer of viral capsomeres but do not degrade the viral core proteins which form the subviral particle (SVP).

TL;DR: A model of MuLV is proposed, which suggests that the internal component of the core, the nucleoid, is a filamentous structure, which may possess helical symmetry and a smooth membranous layer underlying the layer of regularly arranged subunits was observed in liberated cores.

TL;DR: A model for influenza viruses A and B is proposed which relates their polypeptide composition to their structure and evidence is presented that the ribonucleoprotein (RNP) is enclosed in a sac of protein made up of carbohydrate-free molecules of 26,000 daltons.

TL;DR: RSV-Prague was harvested from transformed chick embryo fibroblasts 5, 10, 20, 60, and 180 min after release and compared with virus harvested after 12 and 24 hr with respect to the nature of its RNA, polypeptide constitution, and ability to use its own RNA and added DNA as primer/template for DNA synthesis to suggest that the location of the enzyme(s) responsible forDNA synthesis differed in immature and mature virus particles.

TL;DR: The fact that the AMV structure becomes disturbed upon addition of its own RNA confirms the idea that in this virus particle the protein-protein interactions are of minor importance.

TL;DR: It was concluded that the presence of the N gene conveying the necrotic response does not influence the inherent capacity of tobacco leaf cells to synthesize TMV and that the expression of this gene requires an interaction of invaded cells with cells of the surrounding tissues.

TL;DR: Preparations of purified virions of human rhinoviruses type 2 and type 14 and of an equinerhinovirus are each homogeneous by the criteria of electron microscopy and rate-zonal and isopycnic gradient centrifugation.

TL;DR: Virions were dissociated into their constituent polypeptides which were then analyzed by means of SDS-urea polyacrylamide gel electrophoresis followed by staining with Coomassie Brilliant Blue or by autoradiography.

TL;DR: Two distinct types of particles were isolated during purification of bluetongue virus from infected mouse L fibroblasts, both were infectious and contained a double-stranded RNA genome composed of ten segments ranging in molecular weight from 2.7 × 106 to 0.28 × 106 daltons.

TL;DR: The tetR marker was found to be integrated at proA near the P22 prophage attachment site of the recipient chromosome, confirming the previous result of Dubnau and Stocker (1964), who used an independently isolated R factor with drug resistance markers similar to those of 222.

TL;DR: A model is proposed for the subunits of the inclusion body protein lattice which explains the arrangement seen both in section and in aggregates of protein from alkali-treated polyhedra.

TL;DR: Infectivity of the free-RNA exocortis virus from Gynura aurantiaca was maximal 40–60 days post-infection with the virus still recoverable after 140 days, suggesting the presence of a low molecular weight “tRNA-Like” or a RNA: DNA hybrid molecule for the infectious form of CEV.

TL;DR: A recombinant that has the transforming activity of a Rous sarcoma virus (helper-independent) and the subgroup specificity of an avian leukosis virus has been isolated from cells infected with these two types of virus.

TL;DR: Findings indicate that carbohydrates are present in the viral envelope in 2 layers: (1) in the spikes covalently linked to protein, (2) inThe lipid layer covalent linked to lipid.

TL;DR: A complete genetic map of the temperate Salmonella phage P22 has been constructed using a variety of methods and shows clustering of related functions.

TL;DR: A microtiter technique was developed which allowed screening of large numbers of clones of murine leukemia virus for the presence of temperature-sensitive mutants and 9 mutant viruses which have a markedly reduced infectivity at the nonpermissive temperature have been isolated.

TL;DR: The results confirm the belief that the surface projections of avian RNA tumor viruses represent the type-specific antigens.

TL;DR: Specific antisera to the isolated hemagglutinin subunits of representative A2 influenza viruses were used to examine antigenic variation among influenza A2 viruses and, in particular, the origin of the Hong Kong strain of influenza (A2/Hong Kong/68).

TL;DR: Ability to synthesize single-stranded RNA (mRNA) is less temperature-sensitive; using a low-temperature hybridization technique which causes no single-Strand breakage, it has been found that, although mutants of all three groups synthesize less mRNA at the nonpermissive temperature than wild-type virus, all 10 species of mRNA are formed.

TL;DR: Interactions of the bands of paramyxoviruses (HVJ, NDV) with lipids resulted in formation of active hemolysins, but similar mixtures made with influenza virus did not, which suggested that lipids act as an activator for formation of theactive hemolysin.