- Volume 24, Issue 1, 1974
Volume 24, Issue 1, 1974
- Articles
-
-
-
Pilus-dependence of Four Pseudomonas aeruginosa Bacteriophages with Non-contractile Tails
More LessSUMMARYFour Pseudomonas aeruginosa bacteriophages with non-contractile tails were thought to be pilus-dependent because they did not lyse pilus-less host mutants. They were, therefore, subjected to a series of tests based on the properties of known pilus phages. The lytic spectra of the phages and their efficiency of adsorption to various host mutants were compared with those of the RNA pilus phage PP7 and the tailed pilus phage PO4. Electron microscopy was used to locate the sites of adsorption of the candidate phages on sensitive host cells, and on cells of host mutants with non-retractile pili. In all respects, the four isolates behaved like known pilus phages, and it was concluded that they too were pilus-dependent. A detailed model for the adsorption process of one of the isolates (M6) is proposed on the basis of high-resolution electron micrographs.
-
-
-
-
A Temperature-sensitive Mutant of Herpes Simplex Virus Type 1 Defective in the Synthesis of the Major Capsid Polypeptide
More LessSUMMARYThe virus-induced polypeptides synthesized in human embryonic lung cells infected with ts 4, a DNA negative temperature-sensitive mutant of herpes simplex virus type I, were examined at the permissive (34 °C) and non-permissive (39 °C) temperatures using SDS-polyacrylamide gel electrophoresis. Cells infected with ts 4 at 34 °C synthesized virus-specific polypeptides in the same proportion as did wild-type-infected cells at 34 and 39 °C. Cells infected with ts 4 at 39 °C exhibited multiple polypeptide defects, the most prominent of which was the inhibition of the synthesis of the major virus capsid polypeptide, VP154. The expression of the temperature-sensitive defect relating to VP154 only occurred prior to 4 h after infection, as shown by shift-up studies. The expression of the temperature-sensitive defect at 39 °C relating to VP154 could be reversed by shifting down infected cells to 34 °C, even after 12 h at the non-permissive temperature. This reversal occurred in the presence of cytosine arabinoside but not in the presence of actinomycin D.
-
-
-
Two Protein and Two RNA Species in Particles of Strawberry Latent Ringspot Virus
More LessSUMMARYPurified preparations of strawberry latent ringspot virus (SLRV) contain a major (126S) component which tends to aggregate, and sometimes a minor component of about 58S. The major component contains two RNA species, of mol. wt. 2.6 × 106 and 1.6 × 106; some particles contain one molecule of the larger species and others apparently contain two molecules of the smaller species. The virus particles migrated as a single component both in immunoelectrophoresis tests and when electrophoresed in polyacrylamide gels. In polyacrylamide they were retarded by an increase of gel strength slightly more than were particles of raspberry ringspot virus. Virus preparations yielded two polypeptides of mol. wt. 44000 and 29000 in a molar ratio of about 1 to 1.3. In size and number of polypeptide species, SLRV differs from other nepoviruses and resembles broad bean wilt virus and comoviruses, but it did not react with antisera to seven of these viruses. The cryptogram of SLRV is R/1:2.6/37 + (2 × 1.6/42):S/S:S/Ne.
-
-
-
Inhibition of Foot-and-Mouth Disease Virus Replicase by Frog Virus 3 Particles
More LessSUMMARYA cell-free system synthesizing FMDV RNA has been shown to be inhibited efficiently by purified FV3 particles. Neither vaccinia nor herpes virus particles produced this effect. The results obtained provide direct evidence that a structural component (or components) or FV3 is responsible for the inhibition.
-
-
-
The Replication of Semliki Forest Virus
More LessSUMMARYUsing polyacrylamide gel electrophoresis, column chromatography on CF11 cellulose and salt precipitation, together with ribonuclease treatment, we have identified, in chick cells infected with Semliki Forest virus, four species of virus-specified single-stranded RNA, three species of double-stranded RNA and a multi-stranded RNA species. The mol. wt. of the four single-stranded RNA species were 4.0 × 106, 3.1 × 106, 2.3 × 106 and 1.8 × 106.
The kinetics of virus-specified RNA synthesis were studied in virus-infected cells, both early in infection and when virus-specified RNA synthesis was at the maximum rate. The first species of virus RNA detected were the multi-stranded and double-stranded species of RNA. The first single-stranded species detected was the 42S virus particle RNA, at 1.5 h after infection. The average time taken to synthesize a molecule of virus-specified RNA was between 1 and 1.5 min. Multi-stranded and double-stranded RNA both had the properties expected of an intermediate in RNA synthesis, and the number of single-stranded equivalents in the multi-stranded species was 4.3. The data show that synthesis of virus RNA is mainly semi-conservative and that the virus messenger RNA is of the same polarity as the genome.
-
-
-
Host-dependent Properties of Coliphage ϕW and its Female-specific Host-range Mutants ϕ3 and ϕ4
More LessSUMMARYColiphage ϕW and its female-specific host range mutants φ3 and ϕ4 were grown on Escherichia coli B and strain D31, an LPS mutant of E. coli K12. Comparison of phage samples from centre and halo of single plaques indicates that host-range mutants of ϕ3 type are enriched in halos on strain D31. For ϕW there was a decreased adsorption to full-grown cells, for ϕ3 there was only a minor change. Caesium chloride gradients have shown that ϕ3 is denser than ϕW and ϕ4. After growth on strain D31 both ϕW and ϕ3 produced non-infectious tail-less particles, and burst sizes were reduced correspondingly. It is suggested that the assembly of the tail could be blocked by an assumed LPS precursor.
-
-
-
The Subcellular Localization of Virus-specific RNA in Influenza Virus-infected Cells
More LessSUMMARYThe synthesis of complementary RNA (cRNA) precedes that of virus particle RNA (vRNA) in fowl plague virus-infected cells. Early cRNA synthesis occurs in the cytoplasm, while the later vRNA synthesis is a nuclear event. Influenza RNA synthesized in infected cells does not contain poly A sequences, as judged by binding to nitrocellulose filters under controlled conditions.
-
-
-
The Infection of Tobacco Protoplasts with Pea Enation Mosaic Virus
F. Motoyoshi and R. HullSUMMARYTobacco protoplasts inoculated with pea enation mosaic virus (PEMV) contained virus antigen which was detectable by fluorescent antibody staining 15 h or more after inoculation. Increase in the proportion of fluorescing protoplasts and in the intensity of fluorescence with time of culture suggested that new virus antigen was synthesized. At early stages the fluorescence was found both in the nucleus and in the cytoplasm, but by about 48 h it was more restricted to the nucleus. The uptake of [32P] into virus and into virus RNA indicated that PEMV multiplied in the protoplasts, but the yield of virus was relatively low, about 1 to 5 × 104 particles per infected protoplast. The optimum inoculation conditions for routine infection as assessed by fluorescent antibody staining were 1.5 µg/ml PEMV, 1.5 µg/ml poly-l-ornithine, and pH 4.7. Protoplasts could be infected in the absence of poly-l-ornithine at the higher PEMV concentrations. Actinomycin D added to the culture medium reduced the number of fluorescing protoplasts and the intensity of fluorescence.
-
-
-
Newcastle Disease Virus-induced Plasma Membrane Damage
More LessSUMMARYChick embryo fibroblasts infected by Newcastle disease virus release cellular enzymes into the overlay medium. The kinetics of release were determined for two cytoplasmic enzymes, lactate dehydrogenase (LDH) and glutamic oxaloacetic transminase, and a lysosomal enzyme, betaglucuronidase. Permeability studies showed that this release was accompanied by an alteration in the permeability of the plasma membrane of infected cells. Both [14C]-sucrose and [14C]-dextran entered infected cells at times when release of enzymes was observed, 6 h post-infection, while sucrose entered cells by 4 h post-infection, before release of enzymes could be detected. The addition of cycloheximide or 2-deoxy-d-glucose to infected cells that were already leaking LDH showed that glycoprotein synthesis is required for the virus-induced release of LDH. Stabilization of membrane permeability was accompanied by stabilization of protein synthesis after virus-induced inhibition, and by a decrease in the virus antigens in the plasma membrane. It is hypothesized that the structural alterations of the plasma membrane, indicated by the presence of new virus antigens, are responsible for the functional alterations observed.
-
-
-
The Induction of Deoxythymidine Kinase by Bacteriophage T4
More LessSUMMARYA mutant of Escherichia coli, tdk 32, defective for deoxythymidine kinase (ATP: thymidine 5′-phosphotransferase EC 2.7.1.21) and therefore unable to incorporate thymidine into DNA has been used to study alterations in thymidine utilization resulting from phage infection. Infection by the T-even phages leads to the rapid incorporation of [3H]-thymidine into DNA which results from the induction of deoxythymidine kinase activity as first reported by Hiraga, Igarashi & Yura (1967). No effect was observed following infection of tdk 32 by phages T3, T7, λ, Pl and Mu-1. The T4-induced enzyme differs from the wild-type cell enzyme in several properties including heat stability, deoxycytidine triphosphate stimulation and pH optimum and the ability to induce deoxythymidine kinase can be lost by mutation in a T4 gene (tk) linked to rI. T4tk mutant-infected tdk 32 cells fail to incorporate [3H]-thymidine or 5-bromodeoxyuridine into DNA and the latter property formed the basis for the selection of the phage mutants. The T4tk gene is non-essential for growth both in wild type and tdk mutant cells since deoxythymidine monophosphate can be synthesised by the de novo pathway.
-
-
-
Electron Microscopic Observations on the Entry of Influenza Virus into Susceptible Cells
More LessSUMMARYInfluenza A2 virus particles were observed attached to the surface of chick CAM after 1 h at 4 °C. After incubation at 35 °C, virus particles were seen inside cytoplasmic vesicles (viropexis). Subsequently, the virus particles penetrated the vacuolar membranes and uncoating was observed within the cytoplasm without the intervention of lysosomal enzyme. Fusion of virus coat with cell membrane was not thought to play a part in virus entry. The pinocytosis of virus was shown to be an active process, triggered by the attachment of virus to the cell membrane.
Viropexis occurred in cells treated with amantadine, cytochalasin B and colchicine and in normal cells to which heated virus had been added. Virus was seen eluting after treatment with antihaemagglutinin antibody, but after treatment with antineuraminidase antibody, the virus did not elute; in neither case did the virus enter the cells in the presence of antibody.
-
-
-
Transformation of Rat Embryo Cells by Temperature-sensitive Mutants of Herpes Simplex Virus
More LessSUMMARYRat embryo cells have been transformed by temperature-sensitive mutants of herpes simplex type 2 and by wild-type virus of herpes simplex types 1 and 2. Transformation was scored using the morphological criterion of focus formation and the cell changes that lead to the final focus are described.
Herpes specified antigens can be detected in at least 50% of these transformed rat embryo cells by immunofluorescence studies on unfixed material.
Transformation experiments using hamster embryo cells and HSV-2 strain 333 are also described. These transformed cells are shown to be tumourigenic in newborn hamsters. Tumour cells in turn, as a single cell suspension, produce fresh tumours in animals up to 2 weeks old with almost 100% efficiency. Tumour cells also continue to retain the herpes specific antigens.
-
-
-
Inactivation of some Bacterial and Animal Viruses by Exposure to Liquid-air Interfaces
More LessSUMMARYSurface inactivation of the bacteriophages T1, T3, T5, MS2, of EMC virus and Semliki Forest virus was studied, exposing the viruses to a large air/water interface by aeration or by rotating the fluid in a spherical flask. EMC virus in 1 m-NaCl was not sensitive to this treatment, phage T3 and T5 were only little affected, but the phages T1 and MS2 and Semliki Forest virus were rapidly inactivated by bubbling air or nitrogen gas through the suspension. In salt solutions at rest no inactivation of these viruses was observed. Inactivation by aeration was prevented by addition of peptone, by apolar carboxylic acids and by the surface active agent OED. If a large solution/glass interface is present, some loss of virus occurs by adsorption to the glass surface. Phenylalanine protected against adsorption to the glass surface, but protected less effectively against inactivation by aeration. The rate of surface inactivation was strongly dependent on the salt concentration in the medium. At low NaCl concentration (0.01 m) nearly no inactivation was found for phage T1 and MS2 and phage T3 was not sensitive to aeration in 1 m-NaCl but was rapidly inactivated in 2.6 m-NaCl. The rate of inactivation decreased with time of shaking and in the case of phage T1 a nearly completely resistant fraction of 10−4 of the original particles remained. The resistance against surface inactivation was a non-heritable property. Resistance against thermal inactivation was not correlated with resistance to surface inactivation, suggesting that the mechanism of inactivation differs in these processes.
-
-
-
The IgG Receptor Induced by Herpes Simplex Virus: studies using Radioiodinated IgG
More LessSUMMARYFurther evidence is presented that the receptor induced on the surface of cells infected with herpes simplex virus is specific for the Fc fragment of the IgG molecule of several species. A method has been developed for quantitative studies of this receptor using rabbit IgG labelled with [125I]. The effects of actinomycin D, puromycin, and cytosine arabinoside on the development of the receptor during the virus growth cycle are described. Evidence was obtained of a turnover of membrane receptors after infection.
-
-
-
The Characterization of Bacteroides fragilis Bacteriophage Recovered from Animal Sera: observations on the Nature of Bacteroides Phage Carrier Cultures
R. Keller and Nancy TraubSUMMARYA group of bacteriophages active on Bacteroides fragilis have been isolated from a number of animal sera including calf, foetal calf, lamb, chicken and rabbit. The phages are specific for Bacteroides fragilis; no lytic activity was detected on 36 strains of Bacteroides oralis, 6 strains of Bacteroides melaninogenicus and seven strains of the genus Fusobacterium. Some characteristics of these bacteriophages such as adsorption constants and single-step growth experiments as well as electron micrographs are presented. The B. fragilis host-phage system readily develops a stable phage-bacterium association, i.e. phage carrier cultures. Broth cultures infected with phage at high multiplicities, demonstrated active bacterial growth coincident with phage production. Cultivation of phage carrier strain 12 in medium containing phage antisera eliminated phage carriage. The phage-cured cultures yielded a mixture of phage-sensitive and phage-resistant clones and evidence was obtained of a rapid rate of alternation between these two phenotypes. The simultaneous production of both phage and bacteria in B. fragilis carrier cultures may be ascribed to the continuous development of phage-sensitive organisms from a phage-resistant population.
-
-
-
The Structure of Nudaurelia capensis β Virus: the First Example of a Capsid with Icosahedral Surface Symmetry T = 4
More LessSUMMARYThe three-dimensional reconstruction from electron micrographs of a virus isolated from larvae of the pine emperor moth, Nudaurelia capensis β virus, shows that its surface structure is based on the T = 4 icosahedral surface lattice. The 240 protein subunits are clustered in trimers with the four trimers per icosahedral face approximately planar but with deep grooves between adjacent faces.
-
-
-
Integrity of Cell-bound Poly(I).Poly(C)
More LessSUMMARYThe acid-insoluble radioactivity associated with the cells following incubation of the cells with [3H]-labelled poly(I).poly(C) [poly(I).poly(C)* for 1 h has been analysed by sucrose gradient velocity ultracentrifuging. Intact (poly(I).poly(C)* was recovered from primary rabbit kidney (PRK) cells, partially degraded poly(I). poly(C)* was recovered from mouse L 929 cells and completely degraded material was recovered from HeLa and VERO cells. Priming of the cells with homologous interferon did not alter the sedimentation profile of cell-associated poly(I).poly(C)* in PRK, L 929 or HeLa cells.
-
-
-
Induction of Antiviral Resistance in Nicotiana glutinosa Plants by treatment with Trichothecium Polysaccharide and its reversal by Actinomycin D
More LessSUMMARYTrichothecium polysaccharide induced local and systemic resistance to infection by tobacco mosaic virus when applied to Nicotiana glutinosa leaves two days before virus inoculation. The resistance induced by 2.5 mg/ml of the polysaccharide was approximately halved by simultaneous application of 10 µg/ml actinomycin D.
-
-
-
Absence of a Requirement for Host Polypeptides in the Herpes Virus Thymidine Kinase
More LessSUMMARYActive herpes simplex virus-specific thymidine kinase was precipitated with specific antiserum from extracts of infected BHK 21 cells which had been differently labelled with radioactive amino acids before and after infection. Analysis of the content of pre- and post-infection isotope in polypeptides separated electrophoretically from these immune-precipitates demonstrated the single, virus-specific, polypeptide labelled with post-infection label. No new polypeptide was detected with the pre-infection label and the low content of pre-infection isotope indicated the absence of any pre-formed host protein in the herpes thymidine kinase. The thymidine kinase specific antiserum, raised in rabbits against infected rabbit kidney cells, precipitated polypeptides of indistinguishable mol. wt. (44000) from BHK 21 cells and HEp-2 cells infected with the same strain of herpes simplex type 1.
-
-
-
Modifications by Sodium auro-thio-malate of the expression of Virulence in Mice by defined strains of Semliki Forest Virus
More LessSUMMARYThe responses of mice to infection by defined virulent or avirulent strains of Semliki Forest virus have been modified by the prior administration i.p. of sodium auro-thio-malate. This resulted in enhancement of the efficiency of infection and later modifications (potentiation) of the outcome of that infection. These distinct changes were associated with an enhanced virus invasion of the brain but not with any detectable depression of the humoral antibody response. These events are considered in relation to the multiple effects of alternative ‘immunosuppressive’ drugs.
-
Volumes and issues
-
Volume 105 (2024)
-
Volume 104 (2023)
-
Volume 103 (2022)
-
Volume 102 (2021)
-
Volume 101 (2020)
-
Volume 100 (2019)
-
Volume 99 (2018)
-
Volume 98 (2017)
-
Volume 97 (2016)
-
Volume 96 (2015)
-
Volume 95 (2014)
-
Volume 94 (2013)
-
Volume 93 (2012)
-
Volume 92 (2011)
-
Volume 91 (2010)
-
Volume 90 (2009)
-
Volume 89 (2008)
-
Volume 88 (2007)
-
Volume 87 (2006)
-
Volume 86 (2005)
-
Volume 85 (2004)
-
Volume 84 (2003)
-
Volume 83 (2002)
-
Volume 82 (2001)
-
Volume 81 (2000)
-
Volume 80 (1999)
-
Volume 79 (1998)
-
Volume 78 (1997)
-
Volume 77 (1996)
-
Volume 76 (1995)
-
Volume 75 (1994)
-
Volume 74 (1993)
-
Volume 73 (1992)
-
Volume 72 (1991)
-
Volume 71 (1990)
-
Volume 70 (1989)
-
Volume 69 (1988)
-
Volume 68 (1987)
-
Volume 67 (1986)
-
Volume 66 (1985)
-
Volume 65 (1984)
-
Volume 64 (1983)
-
Volume 63 (1982)
-
Volume 62 (1982)
-
Volume 61 (1982)
-
Volume 60 (1982)
-
Volume 59 (1982)
-
Volume 58 (1982)
-
Volume 57 (1981)
-
Volume 56 (1981)
-
Volume 55 (1981)
-
Volume 54 (1981)
-
Volume 53 (1981)
-
Volume 52 (1981)
-
Volume 51 (1980)
-
Volume 50 (1980)
-
Volume 49 (1980)
-
Volume 48 (1980)
-
Volume 47 (1980)
-
Volume 46 (1980)
-
Volume 45 (1979)
-
Volume 44 (1979)
-
Volume 43 (1979)
-
Volume 42 (1979)
-
Volume 41 (1978)
-
Volume 40 (1978)
-
Volume 39 (1978)
-
Volume 38 (1978)
-
Volume 37 (1977)
-
Volume 36 (1977)
-
Volume 35 (1977)
-
Volume 34 (1977)
-
Volume 33 (1976)
-
Volume 32 (1976)
-
Volume 31 (1976)
-
Volume 30 (1976)
-
Volume 29 (1975)
-
Volume 28 (1975)
-
Volume 27 (1975)
-
Volume 26 (1975)
-
Volume 25 (1974)
-
Volume 24 (1974)
-
Volume 23 (1974)
-
Volume 22 (1974)
-
Volume 21 (1973)
-
Volume 20 (1973)
-
Volume 19 (1973)
-
Volume 18 (1973)
-
Volume 17 (1972)
-
Volume 16 (1972)
-
Volume 15 (1972)
-
Volume 14 (1972)
-
Volume 13 (1971)
-
Volume 12 (1971)
-
Volume 11 (1971)
-
Volume 10 (1971)
-
Volume 9 (1970)
-
Volume 8 (1970)
-
Volume 7 (1970)
-
Volume 6 (1970)
-
Volume 5 (1969)
-
Volume 4 (1969)
-
Volume 3 (1968)
-
Volume 2 (1968)
-
Volume 1 (1967)