bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Herpes Simplex Virus Type 2 Replication by Thymidine
Authors: Cohen Gary H. , Factor Mindie N. , de Leon Manuel Ponce
Published: January 2020

Replication of herpes simplex virus type 2 (HSV-2) was impeded in KB cells which were blocked in their capacity to synthesize DNA by 2 mM thymidine (TdR). The degree of inhibition was dependent upon the concentration of TdR. In marked contrast, HSV-1 is able to replicate under these conditions. The failure of HSV-2 to replicate is probably due to the inhibition of viral DNA synthesis; there was a marked reduction in the rate of DNA synthesis as well as the total amount of HSV-2 DNA made in the presence of 2 mM TdR. We postulated that the effect of TdR on viral replication occurs at the level of ribonucleotide reductase in a manner similar to KB cells. However, unlike KB cells, an altered ribonucleotide reductase activity, highly resistant to thymidine triphosphate inhibition, was found in extracts of HSV-2-infected KB cells. This activity was present in HSV-2-infected cells incubated in the presence or absence of TdR. Ribonucleotide reductase activity in extracts of HSV-1-infected KB cells showed a similar resistance to thymidine triphosphate inhibition. These results suggest that the effect of TdR on HSV-2 replication occurs at a stage of DNA synthesis other than reduction of cytidine nucleotides to deoxycytidine nucleotides.
Specific Fragmentation of DNA of Adenovirus Serotypes 3, 5, 7, and 12, and Adeno-Simian Virus 40 Hybrid Virus Ad2
+
ND1 by Restriction Endonuclease R·
Eco
RI
Authors: Mulder Carel , Sharp Phillip A. , Delius Hajo , Pettersson Ulf
Published: January 2020

The products of complete digestion of duplex DNA of each of seven human adenoviruses with restriction endonuclease R·
Eco
RI ranged from two fragments for adenovirus 7 DNA (Ad7) to six fragments for Ad12 and Ad2 DNA. Viral serotypes from the same subgroups appeared to have related cleavage sites; Ad3 DNA and Ad7 (cl E46-LL) DNA were each cleaved into three fragments, and Ad7 (cl 19) DNA lacked one of the cleavage sites present in Ad3 and Ad7 (cl E46-LL) DNA. One of the cleavage sites in Ad2 DNA was deleted in the DNA′ of adeno-SV40 hybrid virus Ad2
+
ND1, and three of the cleavage sites in Ad2 DNA were missing in Ad5 DNA. Thus, Ad2
+
ND1 DNA was cleaved into five and Ad5 DNA into three fragments. Each fragment represented a unique segment of viral DNA since each fragment was obtained in equimolar amounts and since the sum of the molecular weights of the fragments equaled the molecular weight of the homologous intact adenovirus DNA.
Two Modes of In Vivo Transcription for Genes 43 and 45 of Phage T4
Authors: Hercules Kathleen , Sauerbier Walter
Published: January 2020

Sensitivities of the expression of early genes of phage T4 to UV light were determined at various stages of intracellular development of T4 wild type, a DNA-negative mutant (T4 DO), and T4 tsG1, (a mutant that exhibits delayed expression of some T4 early genes). Whereas the sensitivities of some genes in the T4 wild type and T4 DO remain constant, genes 43 and 45 exhibit greatly reduced sensitivities several minutes after the onset of phage development. Since UV sensitivities are a measure of the distance of a gene from its promotor, these observations indicate a switch from distal, “immediate early” promotors to proximal, “delayed early” promotors for genes 43 and 45. In the tsG1 mutant this decrease in UV sensitivities of genes 43 and 45 does not occur at 42 C, suggesting that at high temperature this mutant does not utilize the delayed early promotors.
Major Polar Lipids of Hepatitis B Antigen Preparations: Evidence for the Presence of a Glycosphingolipid
Authors: Steiner S. , Huebner M. T. , Dreesman G. R.
Published: January 2020

The major phospholipids of hepatitis B antigen, subtype
adw
, were characterized as phosphatidylcholine, sphingomyelin, and lysophosphatidylcholine. In addition, two carbohydrate-containing lipids were observed, one of which was characterized as a non-sialic acid-containing, water-soluble glycosphingolipid. Upon hydrolysis the glycosphingolipid yielded both hydroxy and non-hydroxy fatty acid as well as a long-chain base which was putatively identified as dihydrosphingosine.
Regulation of Synthesis of Two Immunologically Distinct Nucleic Acid-Dependent Nucleoside Triphosphate Phosphohydrolases in Vaccinia Virus-Infected HeLa Cells
Authors: Paoletti Enzo , Cooper Norman , Moss Bernard
Published: January 2020

The two nucleic acid-dependent nucleoside triphosphate phosphohydrolases, previously purified from vaccinia virus cores, were shown to be immunologically distinct enzymes. Antiserum prepared against purified phosphohydrolase I and antiserum prepared against purified phosphohydrolase II only neutralized the activity of that enzyme used as antigen. Both enzymes were induced in HeLa cells after vaccinia infection. DNA-cellulose chromatography was used to purify the two phosphohydrolases from the cytoplasms of infected cells. The enzymes were identified by their different substrate specificities, nucleic acid dependence, and neutralization with specific antiserum. A third chromatographically separable nucleic acid-dependent phosphohydrolase similar to phosphohydrolase I in substrate specificity but not neutralizable by antiserum to either phosphohydrolase I or II, was also isolated from infected cells. No nucleic acid-dependent nucleoside triphosphate phosphohydrolase activity was detected by similar methods from uninfected HeLa cells. Formation of these virus-induced enzymes was prevented by actinomycin D and cycloheximide, indicating a requirement for de novo RNA and protein synthesis, respectively. The kinetics of induction and inhibition by cytosine arabinoside, an inhibitor of DNA synthesis, suggested that synthesis of the phosphohydrolases is a late viral function. Rifampin, an inhibitor of vaccinia virus growth which prevents virion assembly, had no inhibitory effect on the induction of the phosphohydrolases. This result was consistent with the finding that these enzymes exist in a soluble as well as in a particulate form in the cytoplasm of infected cells. Addition of another specific anti-poxviral drug, isatin-β-thiosemicarbazone, to vaccinia-infected cells partially inhibited induction of the phosphohydrolases.
Poly(A) Polymerase from Vaccinia Virus-Infected Cells I. Partial Purification and Characterization
Authors: Brakel Christine , Kates Joseph R.
Published: January 2020

Poly(A) polymerase activity is induced during vaccinia virus infection of HeLa cells. The enzyme is maximally induced at 3.5 h postinfection. Partial purification frees the preparation of RNase activity and RNA polymerase activity. ATP is the substrate for poly(A) synthesis. A small amount of poly(A) is produced from added adenosine diphosphate due to the production of ATP by an adenylate kinase present in the preparation. The incorporation of ATP into poly(A) is dependent on divalent cations (Mg
2+
or Mn
2+
) and is not inhibited by UTP, CTP, or GTP. Poly(U) stimulates ATP incorporation; poly(A) and poly(C) have little effect on ATP incorporation, and poly(dT) is extremely inhibitory. RNA prepared from HeLa cells and from the partially purified poly(A) polymerase (the enzyme preparation contains endogenous RNA [Brakel and Kates]) stimulates ATP incorporation by poly(A) polymerase which was subjected to DEAE-cellulose chromatography. RNase's, pancreatic and T
1
, inhibit the production of poly(A). DNase has little effect. Poly(U) is able to stimulate poly(A) production in the presence of T
1
RNase.
Stimulation of
Herpesvirus saimiri
Expression in the Absence of Evidence for Type C Virus Activation in a Marmoset Lymphoid Cell Line
Authors: Neubauer Russell H. , Wallen William C. , Rabin Harvey
Published: January 2020

Nucleic acid base analogues were used to examine a
Herpesvirus saimiri
(HVS)-infected marmoset lymphoid cell line (MLC-1) for possible association with type C viruses. Synthetic templates poly(rA)·d(pT)
10
and poly(dA)·d(pT)
10
were used to detect RNA-directed DNA polymerase activity in 100-fold concentrated tissue culture fluids. HVS was monitored by immunofluorescence for early, late, and membrane antigens. MLC-1 cells were exposed to 30 μg of 5-bromo-2′-deoxyuridine (BUdR) per ml for 24 h and examined daily. Similar experiments used 5-iodo-2′-deoxyuridine (IUdR) (20 μg/ml) for 30 h or IUdR (20 μg/ml) for 3 days followed by 2% dimethyl sulfoxide for 4 days. Results of these experiments failed to show any type C virus-like polymerase; however, HVS expression was greatly stimulated. BUdR and IUdR enhanced expression of HVS-associated antigens five- to sevenfold, with maximal stimulation being observed 3 to 4 days after removal of the analogue. IUdR-dimethyl sulfoxide treatment was generally less effective. Although more cells showed HVS antigens, the treatments did not increase cell-free infectious virus. The data suggest that HVS-infected lymphoid cells can be stimulated to express virus in a manner similar to that of the Epstein-Barr virus in Burkitt's lymphoma cells. No evidence of type C virus was found in stimulated cultures.
Replication Process of the Parvovirus H-1 III. Factors Affecting H-1 RF DNA Synthesis
Authors: Rhode Solon L.
Published: January 2020

Replication of the single-stranded DNA parvovirus H-1 involves the synthesis of a double-stranded DNA replicative form (RF). In this study, the metabolism of RF DNA was examined in parasynchronous hamster embryo cells. The initiation of RF DNA replication was found to occur late in S phase, as was the synthesis of the DNA upon which subsequent viral hemagglutinin synthesis is dependent. Evidence is presented which indicates that initiation of RF replication requires proteins synthesized in late S phase, but that concomittant protein synthesis is not required for the continuation of RF replication. The data also suggest a requirement for viral protein(s) for progeny strand synthesis. Incorporation of 5-bromo-2′-deoxyuridine (BUdR) into viral DNA resulted in an “all-or-none” inhibition of viral hemagglutinin and viral antigen synthesis. BUdR inactivation of viral protein function was used to explore the time of synthesis of viral DNA serving as template for viral RNA synthesis and the effect of viral protein on RF replication and progeny strand synthesis. Results of this study suggest that parental RF DNA is synthesized shortly after infection, and that viral mRNA is transcribed from only a few copies of the viral genome in each cell. They also support the conclusion that viral protein is inhibitory to RF DNA replication. Density labeling of RF DNA with BUdR, allowing separation of viral strand DNA (V) from viral complementary strand (C), provided additional data in support of the above findings.
Radioimmunoassay for the Major Structural Protein of Hamster Type C Viruses
Authors: Charman Howard P. , Kim Nancy , Gilden Raymond V.
Published: January 2020

A radioimmunoassay for the major, group-specific antigen (p30) of hamster type C viruses was developed. The test detected ∼5 ng of viral protein per ml and was highly specific for hamster viruses when used with homologous antibody. Comparison of three hamster viruses, two being mouse-hamster pseudotypes, in homologous and heterologous intraspecies assays, showed no evidence of type specificity for these proteins. The pseudotype viruses showed no evidence of mouse virus p30 antigenic determinants. An interspecies antigen assay employing
125
I-labeled hamster p30 and anti-feline p30 was completely inhibited by cat (feline leukemia virus), hamster, and rat viruses, to a slightly lesser degree by mouse viruses, and only poorly by RD 114 and Gibbon ape viruses. The Mason-Pfizer virus did not inhibit this assay. Hamster p30 was detected by radioimmunoassay in individual embryos from two LSH hamsters and in several adult tissues, excluding muscle at levels below that required for detection in complement-fixation tests.
Altered Protein Metabolism in Infection by the Late tsB11 Mutant of Simian Virus 40
Authors: Tegtmeyer Peter , Robb James A. , Widmer Chantal , Ozer Harvey L.
Published: January 2020

The DNA of the temperature-sensitive mutant tsB11 is replicated at the same rate as the DNA of wild-type virus in infection at the restrictive temperature. The progeny mutant DNA cannot be distinguished from wild-type DNA by gel electrophoresis and is assembled into a nucleoprotein complex with the same velocity sedimentation characteristics as the wild-type complex. Analysis of in vivo protein synthesis by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoprecipitation techniques demonstrated that the capsid components VP1, VP2, and VP3 of the mutant and wild-type virus are synthesized at a similar rate, but VP1 fails to accumulate within cells infected by tsB11. Furthermore, VP1 is located predominantly in the cytoplasmic rather than in the nuclear fraction of extracts from cells infected by the mutant. Immunofluorescent studies localized virion antigen within the nucleolus as well as the cytoplasm. The altered intracellular distribution and stability of VP1 suggest that it may be the mutant protein of tsB11. The synthesis of a 72,000 dalton protein is consistently induced in significant quantity in cells infected by tsB11 at the restrictive temperature. A protein of the same apparent molecular weight is present in smaller quantities in uninfected cells and is only slightly increased in quantity in cells infected by wild-type virus.
In Vitro Replication of Cowpea Mosaic Virus RNA I. Isolation and Properties of the Membrane-Bound Replicase
Authors: Zabel Pim , Weenen-Swaans Hannemarie , Van Kammen Albert
Published: January 2020

A fraction which contained the membrane-bound cowpea mosaic virus RNA replicase was isolated from cowpea mosaic virus-infected cowpea leaves. The replicase activity appeared on day 1 after inoculation, then increased to reach a maximal on day 4. The increase in enzyme activity preceded the most-rapid virus multiplication. The membrane-bound replicase activity was almost completely insensitive to actinomycin D and DNase. The corresponding fraction from healthy leaves had no RNA-dependent RNA polymerase activity. The viral RNA synthesis in vitro proceeded linearly for 20 min and required all four ribonucleoside triphosphates and Mg
2+
ions. Mn
2+
was a poor substitute for Mg
2+
. The reaction was optimal at pH 8.2. During the whole period of RNA synthesis the in vitro synthesized RNA was at least 70% resistant against RNase in 2 × SSC (0.15 M NaCl plus 0.015 M sodium citrate), but completely digestable by RNase in 0.1 × SSC. Analysis of the products by sucrose gradient centrifugation followed by treatment of separate fractions with RNase demonstrated that both single-and double-stranded RNA were present. Double-stranded RNA sedimented at about 20
S
, with a shoulder at 16
S
to 17
S
. A minor part of the double-stranded RNA sedimented below 10
S
. Single-stranded RNA sedimented with the same rate as the two viral RNAs, 26
S
and 34
S
.
Defective Interfering Passages of Sindbis Virus: Nature of the Intracellular Defective Viral RNA
Authors: Weiss Barbara , Goran Daniel , Cancedda Ranieri , Schlesinger Sondra
Published: January 2020

BHK cells infected with defective-interfering passages of Sindbis virus accumulate a species of RNA (20
S
) that is about half the molecular weight of the major viral mRNA (26
S
). We have performed competitive hybridization experiments with these species of RNA and have established that 20
S
RNA contains approximately 50% of the nucleotide sequences present in 26
S
RNA. Our further studies, however, demonstrate that 20
S
RNA is unable to carry out the messenger function of 26
S
RNA. We found very little of the defective RNA associated with polysomes in vivo. In addition, it was unable to stimulate protein synthesis in vitro under conditions in which 26
S
RNA was translated. We have also examined viral RNA synthesis in BHK cells infected with standard or defective-interfering passages of Sindbis virus. This comparison suggests that defective partioles do not synthesize a functional replicase.
Expression of the Major Internal Viral Polypeptide in Cells Transformed by Wild-Type and Temperature-Sensitive Murine Sarcoma Virus
Authors: Spira Gad , Dreesman Gordon R. , Benyesh-Melnick Matilda , Kit Saul , Somers Kenneth D.
Published: January 2020

Phenotypic expression of the murine intraspecies and interspecies antigenic determinants of the major type C viral structural 30,000-dalton polypeptide, p30, was measured by radioimmunoassay inhibition in cell lines from different species. Uninfected normal rat kidney (NRK) cells did not contain detectable levels of murine intraspecies and interspecies p30 antigen, whereas rat cells transformed by and producing murine sarcoma virus (MSV)-Moloney leukemia virus (M-MSV-MuLV) contained high levels of both murine intraspecies and interspecies p30 antigen. Significant amounts of murine intraspecies and interspecies p30 antigen were detected in wild-type MSV-transformed nonproducer NRK cells. The control of p30 antigen expression was examined in temperature-sensitive MSV-transformed nonproducer cells [NRK(MSV-1b)] which are cold sensitive for maintenance of the transformed phenotype. Both murine intraspecies and interspecies p30 antigens were detected in NRK(MSV-1b) cells when grown at the permissive (39 C) or nonpermissive (33 C) temperature, suggesting that p30 antigen expression is not correlated with maintenance of the transformed phenotype. The results demonstrate that previously undetectable p30 antigens are expressed in MSV-transformed nonproducer NRK cells, and suggest that the expression of p30 antigen may be a useful marker for viral gene expression in mammalian cells.
Structure of the Mouse Mammary Tumor Virus: Characterization of Bald Particles
Authors: Cardiff R. D. , Puentes M. J. , Teramoto Y. A. , Lund J. K.
Published: January 2020

The polypeptide, antigenic, and morphological structure of the mouse mammary tumor virus was studied following protease digestion of intact virions. Intact, untreated virions (ρ = 1.17 g/ml) had characteristic envelope spikes, five major polypeptides, and were precipitated by antisera against gp52. Two of the major polypeptides, with molecular weights of 52,000 (gp52) and 36,000 (gp36), had carbohydrate moieties. Protease treatment resulted in spikeless, “bald” particles (ρ = 1.14 g/ml), which had altered surface antigenicity and which contained neither gp52 nor gp36. These data indicated that gp52 and gp36 were on the viral envelope. Bald particles retained a 28,000 dalton polypeptide (p28) which was proposed as the major internal polypeptide.
Properties and Location of Poly(A) in Rous Sarcoma Virus RNA
Authors: Wang Lu-Hai , Duesberg Peter
Published: January 2020

The poly(A) sequence of 30 to 40
S
Rous sarcoma virus RNA, prepared by digestion of the RNA with RNase T
1
, showed a rather homogenous electrophoretic distribution in formamide-polyacrylamide gels. Its size was estimated to be about 200 AMP residues. The poly(A) appears to be located at or near the 3′ end of the 30 to 40
S
RNA because: (i) it contained one adenosine per 180 AMP residues, and because (ii) incubation of 30 to 40
S
RNA with bacterial RNase H in the presence of poly(dT) removed its poly(A) without significantly affecting its hydrodynamic or electrophoretic properties in denaturing solvents. The viral 60 to 70
S
RNA complex was found to consist of 30 to 40
S
subunits both with (65%) and without (approximately 30%) poly(A). The heteropolymeric sequences of these two species of 30 to 40
S
subunits have the same RNase T
1
-resistant oligonucleotide composition. Some, perhaps all, RNase T
1
-resistant oligonucleotides of 30 to 40
S
Rous sarcoma virus RNA appear to have a unique location relative to the poly(A) sequence, because the complexity of poly(A)-tagged fragments of 30 to 40
S
RNA decreased with decreasing size of the fragment. Two RNase T
1
-resistant oligonucleotides which distinguish sarcoma virus Prague B RNA from that of a transformation-defective deletion mutant of the same virus appear to be associated with an 11
S
poly(A)-tagged fragment of Prague B RNA. Thus RNA sequences concerned with cell transformation seem to be located within 5 to 10% of the 3′ terminus of Prague B RNA.
Electron Microscopy of
Pseudomonas
φ6 Bacteriophage
Authors: Ellis L. F. , Schlegel R. A.
Published: January 2020

φ6 bacteriophage from
Pseudomonas phaseolicola
has a pleomorphic shape due to an outer layer of lipid. This layer was removed with organic solvents or sodium dodecyl sulfate revealing a 50-nm cubic particle. The virus was found only in the central portion of the cell and not near the cell wall.
Structural Proteins of Mammalian Oncogenic RNA Viruses: Immunological Characterization of the p15 Polypeptide of Rauscher Murine Virus
Authors: Strand Mette , Wilsnack R. , August J. T.
Published: January 2020

The immunological properties of the purified 15,000-dalton protein of Rauscher murine type-C virus were analyzed by radioimmunoassay. The majority of the antigenic determinants of this protein were found to be remarkably specific to Rauscher and Friend virus and to a lesser extent to Moloney virus. Determinants reactive with other murine viruses (group-specific) or type-C viruses of other species (interspecies) were also demonstrated but were minor components of the total antigenic specificities of the protein. The results provide evidence that the antigenic properties of this protein specify the Friend-Moloney-Rauscher subgroup of type-C viruses.
Type-C RNA Virus Gene Expression in Human Tissue
Authors: Strand Mette , August J. T.
Published: January 2020

Partially purified fractions of human tissues have been analyzed by competition radioimmunoassay for the presence of two of the principle structural components of type-C RNA viruses, the major core protein (p27 to p30) and the major envelope glycopeptides (gp69/71). Screening of tissues was carried out by use of a heterologous assay system of
125
I-labeled Rauscher murine virus p30 antigen and anti-RD 114 virus serum which was found to detect a class of interspecies determinants common to murine, feline, and primate viruses. A competitor with the same apparent affinity for antibody binding as that of purified viral core proteins was found in relatively high concentration in tissues from patients with systemic lupus erythematosus, in some neoplastic tissues, and also in normal human tissues. This competitor from a lupus spleen chromatographed on phosphocellulose and showed size fractionation during gel filtration similar to known p27 to p30 viral proteins. An immunologically reactive protein was also demonstrated by immunodiffusion and by immunoprecipitation of
125
I-labeled human protein with anti-RD 114 p28 serum. Analysis of these human competitor proteins with homologous assay systems of viral core proteins and corresponding antisera showed that all, including the normal tissue extracts, appear similar to core proteins of known viruses, especially the RD 114 and woolly monkey species. A hypothesis suggested by these data is that many, if not all, humans harbor at least part of the genome of one or more type-C viruses, the properties of which are similar to those of viruses from other mammalian species, particularly primates.
Inactivation of the ATP-dependent DNase of
Escherichia coli
After Infection with Double-Stranded DNA Phages
Authors: Sakaki Yoshiyuki
Published: January 2020

The ATP-dependent DNase activity of
Escherichia coli
disappeared or was markedly reduced after infection with double-stranded DNA phages, T2, T3, T4, T5, T6, T7, λ, φ80, and P1, but not with the single-stranded DNA phage f1, or the RNA phage Qβ. This DNase activity was not reduced when chloramphenicol was added prior to phage infection.
Studies of polyoma virus DNA: cleavage map of the polyoma virus genome
Authors: Chen M C , Chang K S , Salzman N P
Published: January 2020

A small-plaque polyoma virus, MPC-1, was isolated from a mouse plasmacytoma. The DNA of this polyoma virus was cleaved with a restriction enzyme from Haemophilus influenzae (Hin d), and the molecular weights of the limit products were analyzed by electrophoresis and electron microscopy. The fragments produced by this enzyme have been ordered by analysis of partial digest products. A physical map of the polyoma virus genome was then constructed.
Effect of cytosine arabinoside on viral-specific protein synthesis in cells infected with herpes simplex virus
Authors: Ward R L , Stevens J G
Published: January 2020

The relationship between viral DNA and protein synthesis during herpes simplex virus type 1 (HSV-1) replication in HeLa cells was examined. Treatment of infected cells with cytosine arabinoside (ara-C), which inhibited the synthesis of HSV-1 DNA beyond the level of detection, markedly affected the types and amounts of viral proteins made in the infected cell. Although early HSV-1 proteins were synthesized normally, there was a rapid decline in total viral protein synthesis beginning 3 to 4 h after infection. This is the time that viral DNA synthesis would normally have been initiated. ara-C also prevented the normal shift from early to late viral protein synthesis. Finally, it was shown that the effect of ara-C on late protein synthesis was dependent upon the time after infection that the drug was added. These results suggest that inhibition of progeny viral DNA synthesis by ara-C prevents the "turning on" of late HSV-1 protein synthesis but allows early translation to be "switched off."
Alteration of capsid proteins of coxsackievirus A13 by low ionic concentrations
Authors: Cords C E , James C G , McLaren L C
Published: January 2020

Several group A coxsackieviruses (A13, 15, 18, and 21), but not polioviruses or group B coxsackieviruses, are rapidly inactivated in low ionic strength solutions at neutral pH. The extent of inactivation is dependent upon temperature and molarity. Virions inactivated in this manner contain a normal complement of infectious RNA which remains in a state resistant to the action of ribonuclease. However, more than 95% of the virus particles are unable to attach to susceptible cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals that coxsackievirus A13 virions contain five structural polypeptides (VP1, VP2a, VP2b, VP3, and VP4). Electrophoretic analysis indicates that inactivation of coxsackievirus A13 in low ionic strength solutions is due to the specific loss of the smallest polypeptide VP4 from the virus particle. These results suggest that adsorption of coxsackievirus A13 to receptors on susceptible cells is dependent upon the presence of the capsid protein VP4.
Human cytomegalovirus stimulates host cell RNA synthesis
Authors: Tanaka S , Furukawa T , Plotkin S A
Published: January 2020

Human cytomegalovirus infection of human fibroblast cells (WI-38) induced cellular RNA synthesis. The RNA synthesis in infected cultures preceded the synthesis of viral DNA and progeny virus by approximately 24 h. RNA species synthesized in infected cells included ribosomal 28S and 18S; and 4S transfer RNA; all were markedly increased in comparison to uninfected cells. This induction of host cell RNA synthesis was dependent upon a protein(s) that was synthesized during the early stages of infection.
Inhibition of bacteriophage PBS2 replication in Bacillus subtilis by phleomycin
Authors: Post L , Price A R
Published: January 2020

Phleomycin is an effective inhibitor of the replication of Bacillus subtilis bacteriophage PBS2, whose DNA contains uracil instead of thymine. Phleomycin does not affect the induction of the known phage enzymes involved in deoxyribonucleotide metabolism. But phage DNA synthesis is severely inhibited by phleomycin, and late virion protein synthesis is eliminated. These effects appear to result from a phleomycin-induced degradation of the parental phage DNA. Similar inhibitory and degradative effects on DNA are seen in phleomyinc-treated, uninfected cells. This system is unaffected by the related antibiotic, bleomycin.
Action of Interferon in Enucleated Cells
Authors: Young C. S. H. , Pringle C. R. , Follett E. A. C.
Published: January 2020

Interferon induces protection of enucleated BSC-1 cells against infectious vesicular stomatitis virus production if cells are treated before, but not after, enucleation.
Method for determination of nucleotide sequence homology between viral genomes by DNA reassociation kinetics
Authors: Fujinaga K , Sekikawa K , Yamazaki H
Published: January 2020

A model and appropriate equations were derived for the quantitative estimation of nucleotide sequence homology between two partially related viral genomes by measurement of the initial rate of reassociation of one labeled DNA in the presence of a second unlabeled DNA. The validity and usefulness of this procedure were demonstrated by the analysis of the reassociation kinetics of labeled adenovirus 7 DNA in the presence of unlabeled adenovirus 2 DNA. Based on DNA reassociation, the extent of homology between adenovirus 2 and 7 genomes was found to be 10 to 12%. The duplex formed between adenovirus 2 and 7 DNA had the appropriate thermal stability for a well-matched DNA-DNA hybrid.
Binding properties of avian myeloblastosis virus DNA polymerases to nucleic acid affinity columns
Authors: Grandgenett D P , Rho H M
Published: January 2020

A new method for the analysis and purification of the RNA-directed DNA polymerase of RNA tumor viruses has been developed. This nucleic acid affinity chromatography system utilizes an immobilized oligo (dT) moiety annealed with poly (A). The alpha and alphabeta DNA polymerases of avain myeloblastosis virus bound effectively to poly (A) oligo (dT)-cellulose. Alpha DNA polymerase did not bind effectively to poly (A) oligo (dT)-cellulose, poly (A)-cellulose, or to cellulose. Alphabeta bound to oligo (dT)-cellulose and cellulose at the same extent (approximately 30%), indicating that this enzyme did not bind specifically to the oligo (DT) moiety only. However, alphabeta bound to poly (A)-cellulose two to three times better than to cellulose itself, showing that alphabeta could bind to poly (A) without a primer. Alphabeta DNA polymerase also bound to poly (C)-cellulose, whereas alpha did not. These data show that the alpha DNA polymerase is defective in binding to nucleic acids if the beta subunit is not present. Data is presented which demonstrates that the alphabeta DNA polymerase bound tighter to poly (A). oligo (DT)-cellulose and to calf thymus DNA-cellulose than the alpha DNA polymerase, suggesting that the beta subunit or, at least part of it is responsible for this tighter binding. In addition, alphabeta DNA polymerase is able to reversibly transcribe avian myeloblastosis virus 70S RNA approximately fivefold faster than alpha DNA polymerase in the presence of Mg2+ and equally efficient in the presence of Mn2+. alpha DNA polymerase transcribed 9S globin m RNA slightly better than alphabeta with either metal ion.
Detection of a virus-specific antigen on the surface of herpes simplex virus-transformed cells
Authors: Reed C L , Cohen G H , Rapp F
Published: January 2020

A virion-associated antigen, CP-1, was detected on the surface of hamster cells after transformation by inactivated herpes simplex virus type 1. Presence of the CP-1 antigen on the cells correlates with the synthesis of antibody by tumorbearing hamsters capable of neutralizing both herpes simplex virus types 1 and 2.
Isolation of a Sindbis virus variant by passage on mouse plasmacytoma cells
Authors: Symington J , Schlesinger M J
Published: January 2020

A variant of Sindbis virus has been isolated by growing a stock of virus, previously passaged on chicken embryo cells, in mouse plasmacytoma (MOPC 315) cells in suspension culture. An indirect immunofluorescence test and infective center assay showed that only a small fraction of cells could be infected by the stock wild-type virus, but that the population of virus accumulating after a few passages on the mouse cells had host-range properties distinct from the stock virus. The mouse-passaged virus retained its virulence for the original host and back-passaging of this virus on chicken cells did not change its newly acquired properties. Thus, this variant appears to be a genetically distinct form of Sindbis that adsorbs to and grows much better than the stock virus on several types of mouse cells including cultures of mouse macrophages.
Differential accumulation of virus-specific RNA during the cell cycle of adenovirus-transformed rat embyro cells
Authors: Hoffmann P R , Darnell J E
Published: January 2020

In adenovirus type 2-transformed rat embryo cells there is a threefold greater incorporation of [3-H]uridine into virus-specific RNA early in S phase than in late S or G2. This heightened accumulation of labeled RNA is true for both nuclear and cytoplasmic virus-specific labeling. Inhibition of DNA synthesis decreases the virus-specific RNA labeling, whereas reversal of inhibition again allows the elevated level of virus-specific RNA labeling.
RNA metabolism of murine leukemia virus II. Endogenous virus-specific RNA in the uninfected BALB/c cell line JLS-V9
Authors: Fan H , Besmer P
Published: January 2020

Type C virus-specific RNA sequences of BALB/c endogenous virus were detected in JLS-V9 cells (an uninfected BALB/c derived line) by annealing cell RNA with 3-H-labeled virus-specific DNA. Endogenous viruses used in preparing the 3-H-labeled DNA (mostly xenotropic) was prepared from JLS-V9 cells induced to produce virus with iododeoxyuridine. In whole-cell extracts, two virus-specific RNA species, 38S and 27S, were detected. No 60 to 70S virus-specific RNA was found. The same two species of virus-specific RNA were observed in isolated cytoplasmic RNA and in cytoplasmic RNA selected for polyadenylic acid-containing species by binding and elution from oligo(dT) cellulose. Very little, if any, of the virus-specific RNA was active as messenger RNA on polyribosomes. No virus-specific RNA transcribed from genes coding for the BALB/c endogenous N-tropic virus was detected, since 3-H-labeled DNA prepared from endogenous N-tropic virus did not hybridize measurably with JLS-V9 RNA.
Inhibition of group B arbovirus antigen production and replication in cells enucleated with cytochalasin B
Authors: Kos K A , Osborne B A , Goldsby R A
Published: January 2020

A comparative study of the growth of Sindbis (SIN) virus, a group A arbovirus (togavirus), and Japanese encephalitis (JE) virus, a representative group B arbovirus (togavirus), was conducted in enucleate and nucleate cells. Immunofluorescent tests and yield measurements demonstrated that chicken embryo cells which had been enucleated and subsequently infected with SIN virus produced virus-specific antigens and infectious virus. By contrast, JE failed to replicate or produce virus-specific antigen in cells which had been enucleated before or even 2 h post infection. Studies of the effect of enulceation at various times after infection demonstrated that a nucleus must be present at least 2 and possibly as long as 4 h after infection to produce either JE-specific antigen or infectious JE virus. These studies demonstrate that the replication of SIN, a group A arbovirus (togavirus), which has no nuclear requirement, contrasts sharply with that of a group B arbovirus (togavirus), JE, which may have an initial dependence on a nucleus-associated process.
Identification of a viral protein involved in post-translational maturation of the encephalomyocarditis virus capsid precursor
Authors: Lawrence C , Thach R E
Published: January 2020

Translation of encephalomyocarditis virus RNA in a cell-free system from uninfected Krebs ascites cells results in the synthesis of a major polypeptide product with a molecular weight of approximately 112,000. In contrast, when the viral RNA is translated in a cell-free system from virus-infected cells, this polypeptide is absent and the largest polypeptide produced has a molecular weight of about 100,000. This latter polypeptide comigrates on sodium dodecyl sulfate-gels with in vivo virus capsid precursor A, and the two have identical patterns of CNBr-generated peptides. A polypeptide having a molecular weight of 12,500 is also a major translation product in the system from infected cells (but not from uninfected cells). This polypeptide appears to be generated by cleavage of the NH-2-terminal portion of the viral RNA-dependent polypeptides by a proteolytic activity present in the infected cell-free system. This proteolytic activity copurifies with the 23,000-molecular weight viral capsid protein gamma, found in infected cells, through chromatography on DEAE-cellulose and cellulose phosphate. This suggests that gamma is itself a proteolytic enzyme involved in maturation of the viral capsid precursor.
New Late Gene,
dar
, Involved in DNA Replication of Bacteriophage T4 I. Isolation, Characterization, and Genetic Location
Authors: Wu Jeng-Ren , Yeh Yun-Chi
Published: January 2020

Suppressors of gene 59-defective mutants were isolated by screening spontaneous, temperature-sensitive (
ts
) revertants of the
amber
mutant,
am
C5, in gene 59. Six
ts
revertants were isolated. No gene 59-defective
ts
recombinant was obtained by crossing each
ts
revertant with the wild type, T4D. However, suppressors of gene 59-defective mutants were obtained from two of these
ts
revertants. These suppressor mutants are referred to as
dar
(DNA arrested restoration).
dar
mutants specifically restored the abnormalities, both in DNA synthesis and burst size, caused by gene 59-defective mutants to normal levels. It is unlikely that
dar
mutants are nonsense suppressors since theý failed to suppress
amber
mutations in 11 other genes investigated. The genetic expression of
dar
is controlled by gene 55; therefore,
dar
is a late gene. The genetic location of
dar
has been mapped between genes 24 and 25, a region contiguous to late genes.
dar
appears to be another nonessential gene of T4 since burst sizes of
dar
were almost identical to those of the wild type. Mutations in
dar
did not affect genetic recombination and repair of UV-damaged DNA, but caused a sensitivity to hydroxyurea in progeny formation. The effect of the
dar
mutation on host DNA degradation cannot account for its hydroxyurea sensitivity.
dar
mutant alleles were recessive to the wild-type allele as judged by restoration of arrested DNA synthesis. The possible mechanisms for the suppression of defects in gene 59 are discussed.
Structural polypeptides of rabbit, bovine, and human papillomaviruses
Authors: Favre M
Published: January 2020

The number and apparent molecular weight of the structural polypeptides of Shope rabbit papilloma virus (RPV), bovine papilloma virus (BPV), and human papilloma virus (HPV) were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Up to 10 polypeptides were detected in highly purified BPV and HPV full particles; a close homology was found between the polypeptide composition of both viruses. Purified RPV virions gave a similar polypeptide pattern. The main components of the three papillomaviruses are the major polypeptide (VP1) with a mol wt of approximately 54,000 and the three smaller polypeptides (VP8, 9, 10) with mol wt of about 16,500, 15,500 and 12,500, respectively. VP8, VP9, and VP10 are never detected in empty capsids. When BPV virions were disrupted with alkaline buffer, the six lower-molecular-weight polypeptides (VP5 to 10) remained associated with viral DNA. This suggests that they are internal components of the virions and that the four higher-molecular-weight polypeptides (VP1 to 4) may represent external components. The polypeptide compositions of BPV and polyoma virus, another papovavirus, have been compared. The number of BPV and polyoma virus components (10 and 6, respectively) and the molecular weight of their major polypeptide (54,000 and 44,500, respectively) are different; however, the three main DNA-associated polypeptides of BPV (VP8, 9, 10) and the three histone-like components of polyoma virus (VP4, 5, 6) were shown to have identical apparent molecular weights. The possibility that some of the minor components of papillomaviruses may be proteolytic degradation products or cell protein contaiminants is discussed.
Morphology of BHK-21 Cells Infected with Sindbis Virus Temperature-Sensitive Mutants in Complementation Groups D and E
Authors: Brown Dennis T. , Smith Jonathan F.
Published: January 2020

BHK-21 cells infected with temperature-sensitive mutants of Sindbis virus in complementation groups D and E differed in their appearance under nonpermissive conditions. Cells infected at nonpermissive temperature with virus defective in complementation group E had nucleocapsids attached in large numbers to the inside surface of the host plasma membrane. Infection with a group D mutant produced nucleocapsids that did not attach to the plasma membrane but rather remained free in the cell cytoplasm.
Selective inhibition of herpes simplex virus by 5-amino-2,5-dideoxy-5-iodouridine
Authors: Cheng Y C , Goz B , Neenan J P , Ward D C , Prusoff W H
Published: January 2020

5-Amino-2,5-dideoxy-5-iodouridine, a nel thymidine analogue, is a potent inhibitor of herpes simplex virus type 1 replication. In contrast to most other nucleoside analogues which possess antiviral activity, 5-amino-2,5-dideoxy-5-iodouridine exhibits little, if any, cellular toxicity. Preliminary evidence suggests that 5-amino-2,5-dideoxy-5-iodouridine selectively inhibits viral-specific DNA synthesis.
DNA strand specificity of transcripts produced in vivo and in vitro by RNA polymerase from SP82-infected Bacillus subtilis
Authors: Lawrie J M
Published: January 2020

Phage-specific RNA synthesized early in the infection of Bacillus subtilis with SP82 hybridizes to both heavy (H) and light (L) strands of SP82 DNA nearly equally. Phage RNA synthesized during the middle of the infection hybridizes preferentially to the H strand. The ratio of H/L strand binding of RNAs synthesized in vitro by RNA polymerases isolated from uninfected and infected cells resembles the ratios of early and middle phage RNA classes, respectively. This supports the conclusion that a modified RNA polymerase is required for the transcription of middle RNA classes.
Polyamines in Type 5 Adenovirus-Infected Cells and Virions
Authors: Pett Donald M. , Ginsberg Harold S.
Published: January 2020

The incorporation of
l
-[
14
C]ornithine and [
14
C]putrescine into putrescine, spermidine, and spermine in type 5 adenovirus-infected KB cells was identical to that in uninfected control cells early in infection, but incorporation into putrescine stopped after 8 to 12 h and the rate of incorporation into spermidine was reduced between 12 and 20 h after infection. The amount of polyamines found associated with purified virus could neutralize a maximum of 3 to 4% of the virus DNA, but the small quantities of polyamines detected could not be distinguished from nonspecific binding of polyamines to virions. These data suggest that polyamines are probably not integral components of adenovirus particles.
Temperature-sensitive mutants of simian virus 40 selected by transforming ability
Authors: Yamaguchi N , Kuchino T
Published: January 2020

Eight temperature-sensitive mutants of simian virus 40 which transform rat cells at 32.5 C but not at 38.5 C have been isolated. All the mutants were also temperature sensitive for replication in African green monkey kidney cells and five of them were classified into a single complementation group. No mutant incapable of transforming rat cells at either temperature was isolated.
Structural proteins of mammalian RNA tumor viruses: relatedness of the interspecies antigenic determinants of the major internal protein
Authors: Strand M , August J T
Published: January 2020

The relatedness of antigenic determinants of purified major core proteins of the murine, feline, RD 114/baboon, and woolly monkey/gibbon ape groups of RNA tumor viruses was examined by competition radioimmunoassay. In assay systems of a homologous antigen and antiserum, high affinity competition for binding to all of the antibodies was observed only with the homologous unlabeled protein; the core proteins of other groups of viruses showed only low affinity binding of a small fraction of antibodies, presumably those reactive with the interspecies determinants, at concentrations of competing protein 10- to 100-fold greater than that of the labeled antigen. The cross-reactive (interspecies) antigens of every two viruses were selectively examined by precipitating the purified 125-I-labeled protein with antiserum against each of the other proteins. The extent to which these shared determinants were common to the other viruses was then tested by the effectiveness of the proteins of each virus to compete for antibody binding. Several classes of interspecies determinants were distinguished: those common to two of the groups of viruses, others to three, and some to all four. Moreover, an even greater variety of interspecies determinants was indicated by differences in the affinity of the individual proteins for antibody binding, supporting the hypothesis that there are at least several, if not many, different interspecies determinants with a broad spectrum of antigenic cross-reactivity. These studies suggest that the murine and feline viruses are closely related as they contain cross-reactive antigenic determinants not shared with the other viruses, that the feline virus is more closely related to the woolly monkey virus than to RD 114, and that the RD 114 and woolly monkey viruses retain interspecies determinants shared relatively equally with each of the other viruses.
Characterization of bovine viral diarrhea virus RNA
Authors: Pritchett R , Manning J S , Zee Y C
Published: January 2020

RNA extracted from isopycnically banded [3-H]uridine-labeled bovine viral diarrhea virus with sodium dodecyl sulfate was resolved into one major and two minor components by both sedimentation analysis and electrophoresis in polyacrylamide gels. The major RNA component was estimated to have a 38S sedimentation coefficient. The minor RNA components were estimated to have S values of 31 and 24. The approximate colecular weights were calculated to be 3.22 times 10-6 (38S), 2.09 times 10-6 (31S), and 1.22 times 10-6 (24S). A single broad peak of radioactivity, maximum at 24S, was obtained when sedimentation was conducted under conditions of low ionic strength. All three RNA components were found to be susceptible to digestion with RNase. The presence of multiple RNA components in heterogeneous populations of infectious virus is discussed.
Transfection of Escherichia coli spheroplasts. VI. Transfection of nonpermissive spheroplasts by T5 and BF23 bacteriophage DNA carrying amber mutations in DNA transfer genes
Authors: Benzinger R , McCorquodale D J
Published: January 2020

DNA was extracted from T5 and BF23 phage carrying amber mutations in genes A2, A1, or D9 and tested for its ability to transfect su minus spheroplasts. DNA from T5 am231, defective in gene A2, transfects Escherichia coli su minus recB minus spheroplasts with an efficiency of 16% of that of wild-type T5 DNA, whereas DNA from T5 am16d or BF23 am57, both defective in gene A1 or its equivalent, transfects E. coli su minus recB minus spheroplasts with an efficiency of 1.4% of that of wild-type T5 DNA, provided E. coli su+ bacteria is used as the indicator in all cases. More than 95% of the progeny from the am231, am16d, and am57 DNA that transfects su minus recB minus spheroplasts is still amber mutant. From these efficiencies of transfection we conclude that the product of gene A2 functions mainly in the mechanism of transfer of phage DNA to intact host cells, and that this function is not essential for transfection of spheroplasts. We also conclude that gene A1 controls functions in addition to DNA transfer, in agreement with previous studies which show that mutations in gene A1 have a pleiotropic effect. Apparently, the absence of these additional functions controlled by gene A1 leads to a high frequency of abortive infection. DNA from amber mutants defective in either gene A1 or A2 does not appreciably transfect su minus rec+ spheroplasts, indicating that the products of these two genes may both be needed to protect T5 DNA from the very active rec BC nuclease in spheroplasts.