- Volume 65, Issue 4, 1984
Volume 65, Issue 4, 1984
- Animal
-
-
-
The DNA Polymerase Activity of Vaccinia Virus ‘Virosomes’: Solubilization and Properties
More LessSummaryIntracellular DNA-protein complexes (‘virosomes’) of vaccinia virus have been isolated. The solubilization of the ‘virosome’-bound DNA polymerase activity was attempted by a variety of high-salt extraction procedures. The most efficient of these used 0.3 m-ammonium sulphate followed by brief sonication. The solubilized DNA polymerase activity from the ‘virosomes’, together with the DNA polymerases from 100000 g supernatant fluids from the cytoplasm of infected and uninfected cells were chromatographed on DEAE-cellulose and their properties compared. The ‘virosome’ DNA polymerase activity differed from the soluble vaccinia virus-induced DNA polymerase activity in its requirements for divalent cations and in respect of pH optimum, K m for the deoxyribonucleoside triphosphates and the effect of N-ethylmaleimide.
-
-
-
-
Modulation by the Polyoxotungstate HPA-23 of Epstein–Barr Virus Early Antigen Expression in Raji Cells Treated with Iododeoxyuridine
More LessSummaryThe polyoxotungstate HPA-23 was found to exert a differential effect on the induction of Epstein–Barr virus early antigen in Raji cells induced with 5-iodo-2′-deoxyuridine (IUdR). Thus, treatment of Raji cells concomitantly with IUdR and HPA-23 inhibited early antigen expression, and the extent of inhibition was proportional to the duration of treatment with HPA-23. In contrast, pretreatment of Raji cells with HPA-23 prior to induction with IUdR stimulated early antigen expression in exponentially multiplying but not in stationary-phase cells. HPA-23 alone had no effect one arly antigen expression in Raji cells. Activation of the latent Epstein–Barr virus genome by IUdR is dependent upon incorporation of the thymidine analogue into cellular DNA during the S-phase of the cell cycle. Synthesis of Epstein–Barr virus DNA also takes place during S-phase, suggesting a possible participation in this process of cellular DNA polymerase α which is thought to be responsible for cellular DNA replication and the activity of which increases several-fold during S-phase. Treatment of Raji cells with HPA-23 caused a marked decrease in DNA polymerase α activity, which could result in an inhibition of IUdR incorporation leading to the observed reduction of early antigen expression in cells treated concomitantly with IUdR and HPA-23.
-
-
-
Interferon Production by Epstein–Barr Virus in Human Mononuclear Leukocytes
More LessSummaryInterferon (IFN) production following exposure to Epstein–Barr virus (EBV) was studied in primary human mononuclear leukocytes. When the leukocytes were exposed to EBV (strain B95-8 or P3HR-1) the IFN level reached a maximum 24 h after exposure to the virus, and a gradual decrease followed. A linear relationship was obtained between the input dose of EBV and the IFN titre. The IFN inducibility of leukocytes did not correlate with the EBV infectibility. IFN was also induced by u.v.-inactivated EBV and heat-inactivated EBV, but not by neutralized virus. IFN inducibility varied among adult donors, but there was no significant difference between EBV-seropositive and -seronegative groups. The response of cord blood leukocytes, however, was lower than that of the cells from adults. The activity of all IFN samples in this study was stable to acid and heat and exclusively neutralized by anti-human IFN-α. B cells, T cells and NK cells all produced IFN in response to EBV, but monocytes did not.
-
-
-
Distinctive Characteristics of Crude Interferon from Virus-infected Guinea-pig Embryo Fibroblasts
More LessSummaryCrude interferon preparations from primary guinea-pig embryo cells infected with vesicular stomatitis virus strain T1026R1 were shown to be more sensitive to heat (37 °C), pH 2.0, and SDS than crude mouse interferon. Since the proportion of antiviral activity lost after each treatment was nearly the same, the existence of a single fraction of antiviral activity sensitive to all three treatments was suggested. Support for this possibility was given by the finding that subjecting this guinea-pig interferon to any one of the treatments rendered it insensitive to the effects of the other two.
-
- Plant
-
-
-
Spontaneous Deletion Mutation of Soil-borne Wheat Mosaic Virus RNA II
More LessSummaryThe wild-type (WT) isolate of soil-borne wheat mosaic virus has two species of rod-shaped virions 281 nm and 138 nm in length, which are designated as virions 1.0L and 0.5L, respectively. We reported previously that virions shorter than 0.5L arose in assay plants inoculated with separated and recombined 1.0L RNA and 0.5L RNA and suggested that these short virions were caused by deletion mutation of 0.5L RNA. We now report that these short virions arose after a period of several months in wheat plants that had been inoculated manually with unpurified WT isolate, and also when plants infected naturally in fields infested by the fungal vector, Polymyxa graminis, were grown at 17 °C. The sizes and relative proportions of virions shorter than 0.5L varied both from plant to plant and in the same plant sampled at different times. This indicates that the virions shorter than 0.5L arose by continued and spontaneous deletion mutation of 0.5L RNA.
-
-
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)