bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and Properties of an RNA Polymerase from Influenza Virus-Infected Cells
Authors: Compans Richard W. , Caliguiri Lawrence A.
Published: January 2020

Structures with RNA polymerase activity were isolated from influenza virus-infected cells, and consisted of ribonucleoprotein (RNP) complexes, similar in morphology to the viral internal component or nucleocapsid. The isolation procedure involved fractionation of infected cells in a discontinuous sucrose gradient, in which enzyme activity was concentrated in a fraction of intermediate density which contains both smooth and rough cytoplasmic membranes. The RNPs with polymerase activity were further purified in a velocity gradient, after which the peak fractions showed a 35-fold purification of the polymerase activity when compared with cytoplasmic extracts. The NP polypeptide, which is the subunit of the virion RNP, was the only virus-specific polypeptide detected in these RNP structures.
Agglutination of Sindbis Virus and of Cells Infected with Sindbis Virus by Plant Lectins
Authors: Birdwell Charles R. , Strauss James H.
Published: January 2020

We have examined the agglutination of Sindbis virus and of chick and hamster cells infected with Sindbis virus by two of the plant lectins, concanavalin A and
Ricinus communis
agglutinin. Both lectins agglutinate the virus by binding to the polysaccharide chains of the envelope glycoproteins. Both chick and hamster cells exhibit increased agglutination by the lectins after infection by Sindbis virus. In the case of chick cells infected with Sindbis virus, this increase in agglutinability occurs between 3 and 5 h after infection. Infected and mock-infected cells bind the same amount of
3
H-labeled concanavalin A, which suggests that the increase in agglutination after infection is due to rearrangements at the cell surface rather than to insertion of new lectin binding sites per se.
Production of Specific Fragments of φX174 Replicative Form DNA by a Restriction Enzyme from
Haemophilus parainfluenzae
, Endonuclease HP
Authors: Johnson Paul H. , Lee Amy Shiu , Sinsheimer Robert L.
Published: January 2020

A restriction endonuclease from
Haemophilus parainfluenzae
degrades φX174 replicative form DNA into eight specific fragments, ranging from 1,700 to 150 base pairs and terminated specifically by deoxycytidylic acid.
Analysis of Nuclear Disruption and Binding of Intermediates in Host DNA Breakdown to Membranes After Infection of
Escherichia coli
with Bacteriophages T4 and T7
Authors: Parson Kathleen A. , Warner Huber R. , Anderson Dwight L. , Snustad D. Peter
Published: January 2020

Escherichia coli
DNA polymerase I is implicated in the binding of intermediates in host DNA breakdown to membrane in T4-infected, but not T7-infected, cells. Nuclear disruption is observed in T4-infected
polA1
mutant cells.
Persistent Infection of Cells in Culture by Measles Virus III. Comparison of Virus-Specific RNA Synthesized in Primary and Persistent Infection in HeLa Cells
Authors: Winston Stuart H. , Rustigian Robert , Bratt Michael A.
Published: January 2020

The pattern of actinomycin D-resistant RNA synthesis was examined during primary infection of HeLa cells by virulent Edmonston measles virus and in two HeLa clones persistently infected by the same strain of virus. One of these clones, K11, produces infectious virus of low virulence for HeLa cells, and the other, K11A-HG-1, has thus far failed to yield infectious virus. The patterns of virus-specific RNA synthesized in these three types of infection are qualitatively similar to each other and to the patterns of virus-specific RNA synthesis in other paramyxovirus infections. There were, however, quantitative differences. In addition, virions of the virulent Edmonston strain of measles virus were found to contain high-molecular-weight RNA with a sedimentation constant identical to that of Newcastle disease virus.
Electrophoretic Differences in the Capsid Proteins of Simian Virus 40 Plaque Mutants
Authors: Barban Stanley
Published: January 2020

The structural proteins of three mutants of simian virus 40 (SV40) which differ in plaque size, temperature sensitivity, oncogenicity, host cell restriction, and immunological properties were studied. The polypeptide components of these SV40 strains could not be distinguished by their polyacrylamide gel electrophoretic patterns. When the dissociated virions of two of the mutants were analyzed by the isoelectric focusing technique in a urea gradient, the capsid protein peaks were found to differ significantly in their isoelectric points. The capsid protein of the small-plaque mutant had an isoelectric point of pH 6.51 as compared with pH 6.28 for the large-plaque strain. Isoelectric focusing of the isolated capsid protein revealed three components, a single major subunit and two minor forms. The coat proteins of two of the mutants, small-plaque and minute-plaque strains, were indistinguishable by this technique. The capsid protein peaks obtained by isoelectric focusing were further analyzed by polyacryalmide gel electrophoresis.
Lack of a Close Relationship Between Three Strains of Human Rhinoviruses as Determined by Their RNA Sequences
Authors: Yin Fay H. , Lonberg-Holm K. , Chan S. P.
Published: January 2020

The possible genomic homologies between three serotypes of human rhinoviruses (HRV 1A, HRV 2, and HRV 14) were investigated. First we confirmed that these viruses were unrelated by the criterion of the absence of common antigenic determinants on the surfaces of the native virions, as detected by cross-neutralization of complementfixation. RNA-RNA hybridization was then examined with purified, highly radioactive, double-stranded, replicative-form RNA and excess single-stranded virion RNA. Single-stranded RNA showed 100% homology with the minus strand from the replicative-form RNA of the same type of virus. HRV 1A, HRV 2, and HRV 14 showed low intertypic homologies; these were not significantly greater than those found between the rhinoviruses and polivirus, which were used as a negative control. The immunological relationship and the RNA homology between HRV 1A and HRV 1B were also examined by the above techniques. It was confirmed that HRV 1A and HRV 1B share some surface determinants and it was also found that HRV 1B RNA shares 70% homology with HRV 1A RNA.
Isolation and Properties of
Bacillus subtilis
Strains Lysogenized by a Clear Plaque Mutant of Bacteriophage φ105
Authors: Garro Anthony J.
Published: January 2020

A clear plaque mutant of the temperate
Bacillus
phage φ105 lysogenized a small fraction of infected cells forming an integrated prophage at or near the normal φ105 insertion site. These lysogens exhibited a spontaneous induction rate approximately 1,000-fold lower than wild type and were noninducible (
ind
-
) by mitomycin C. Prophage was induced, however, when competent cultures were incubated with transforming DNA. The
ind
-
phenotype could not be attributed solely to the clear plaque mutation and appears to involve a cell-specific factor. Lysogenization by the clear plaque mutant, in contrast to wild-type phage, did not cause a marked reduction in transformation efficiency.
Heat Induction of Prophage φ 105 in
Bacillus subtilis
: Bacteriophage-Induced Bidirectional Replication of the Bacterial Chromosome
Authors: Rutberg Lars
Published: January 2020

A mutant of
Bacillus subtilis
, dna-1, which cannot initiate new rounds of DNA replication (obtained from N. Sueoka) was lysogenized with wild-type φ 105 and with the heat-inducible mutant φ 105 cts23. Bacteria were incubated at the permissive temperature in the presence of chloramphenicol and then shifted to the nonpermissive temperature where induction of φ 105 cts23 occurs. DNA made after the shift was labeled with a density label, and the distribution of bacterial and phage markers in replicated and unreplicated DNA was determined. Similar experiments were performed with nonlysogenic dna-1 infected with phage φ 105 cts23 after the temperature shift. The results show that after induction of φ 105 cts23 prophage, bacterial markers on either side of the prophage replicate at an increased rate compared to more distant markers. No selective stimulation of bacterial DNA synthesis was observed on infection or after shifting bacteria lysogenic for noninducible phage to the higher temperature. Attempts to suppress the initiation mutation dna-1 by phage φ 105 were unsuccessful.
Relationship Between Replication of Simian Virus 40 DNA and Specific Events of the Host Cell Cycle
Authors: Pages Jacqueline , Manteuil Simone , Stehelin Dominique , Fiszman Marc , Marx Maria , Girard Marc
Published: January 2020

The relationship between replication of simian virus 40 (SV40) DNA and the various periods of the host-cell cycle was investigated in synchronized CV
1
cells. Cells synchronized through a double excess thymidine procedure were infected with SV40 at the beginning or the middle of S, or in G
2
. The first viral progeny DNA molecules were in all instances detected approximately 20 h after release from the thymidine block, independent of the time of infection. The length of the early, prereplicative phase of the virus growth cycle therefore depended upon the period of the cell cycle at which the cells were infected. Infection with SV40 was also performed on cells obtained in early G
1
through selective detachment of cells in metaphase. As long as the cells were in G
1
at the time of infection, the first viral progeny DNA molecules were detected during the S period immediately following, whereas if infection took place once the cells had entered S, no progeny DNA molecule could be detected until the S period of the next cell cycle. These results suggest that the infected cell has to pass through a critical stage situated in late G
1
or early S before SV40 DNA replication can eventually be initiated.
Effects of the Decay of Incorporated Radioactive Phosphorus on the Transfer of the Bacteriophage SP82G Genome
Authors: McAllister William T. , Green D. MacDonald
Published: January 2020

The last genetic markers to be transferred during bacteriophage SP82G infection have a higher sensitivity to the decay of incorporated radioactive phosphorous (
32
P) than those which are located on the proximal end of the genome. If
32
P decay is permitted to take place after DNA transfer is complete (in frozen infective centers) and in the absence of DNA replication, no dependence of marker sensitivity on map position is observed. These results indicate that the decay of incorporated
32
P leads to damages that prevent the efficient transfer of portions of the genome distal to the lesion. At 4 C, failure to transfer some portion of the genome occurs in 49% of all lethal events. Even though damages that prevent transfer of the genome are in themselves lethal, they do not prevent rescue of genetic markers on portions of the genome that are transferred. The portion of the genome that is transferred, is transferred at the same rate as an undamaged genome. We interpret these results to mean that double-strand breaks in the DNA are the lesions that prevent distal transfer and that single-strand breaks have little or no effect on the transfer of the bacteriophage SP82G genome.
Multiple Initiation of Bacteriophage T4 DNA Replication: Delaying Effect of Bromodeoxyuridine
Authors: Carlson Karin
Published: January 2020

Effects of bromodeoxyuridine (BUdR) substitutions in phage T4 DNA on the initial stages of DNA replication were investigated. Electron microscope studies of partially replicated, light (thymidine-containing) T4 DNA revealed the presence of multiple loops and forks. These DNA preparations had no BUdR in either parental or newly synthesized DNA, and the observations thus show that multiple initiation of DNA replication is a normal event in T4 development and is not caused by the presence of BUdR. A comparison of early replicative stages of light and heavy (BUdR-containing) DNA in cells mixedly infected with light and heavy T4 phage showed that early DNA synthesis occurs preferentially on the light template. Heavy and light parental DNA became associated with the protein complex of replicative DNA with equal efficiency, and there was no effect of BUdR on the net rate of DNA synthesis after infection. Newly synthesized DNA from heavy templates sedimented more slowly through alkaline sucrose gradients than did newly synthesized DNA from light templates and appeared to represent fewer replicative regions per molecule. These data indicate that BUdR substitutions in the DNA caused a slight delay in initiation but that replication of heavy DNA proceeded normally once initiated.
Cleavage of Poliovirus-Specific Polypeptide Aggregates
Authors: Korant Bruce D.
Published: January 2020

Zonal electrophoresis resolves two aggregates of poliovirus type 2 cytoplasmic polypeptides. The more negatively charged aggregate contains mainly noncapsid viral-specific polypeptides (NCVP) 2 and x, whereas the other consists of the capsid polypeptides (VP) 0, 1, 2, and 3 (VP0, VP1, VP2, VP3). After treatment with sodium deoxycholate (DOC), the aggregates sediment at 5 to 6
S
. Their electrophoretic mobilities are unaffected by DOC or RNase. The capsid polypeptide aggregate is similar in mobility to virions but can be converted to a faster electrophoretic form, resembling empty capsids, by heating. If infected HeLa cells are allowed to synthesize poliovirus polypeptides in the presence of iodoacetamide, no capsid polypeptides are produced, but rather NCVP1a (the precursor to capsid polypeptides) is accumulated, along with NCVP2 and NCVPx. When analyzed by electrophoresis and centrifugation, uncleaved NCVP1a migrates with the NCVP2-x aggregate. NCVP1a can be cleaved to capsid-like polypeptides in vitro by using extracts of infected cells, but not uninfected cells, indicating either a virus-specified protease or a cellular enzyme activated during infection. After cleavage of NCVP1a by infected cell extracts, the capsid polypeptides which are produced dissociate from the NCVP2-x complex.
Subacute Sclerosing Panencephalitis Measles Virus: Study of Biological Markers
Authors: Hamilton R. , Barbosa L. , Dubois M.
Published: January 2020

Comparative studies between two measles virus strains isolated from patients with subacute sclerosing panencephalitis (SSPE) and a prototype low tissue culture passage Edmonston measles virus are described. Differences were noted in several properties. The findings described in this report suggest that strains of measles virus associated with SSPE have different biological properties and apparently cannot be distinguished from laboratory and field strains of the virus.
Separation of Herpes Simplex Virus-Induced Antigens by Concanavalin A Affinity Chromatography
Authors: De Leon Manuel Ponce , Hessle Helena , Cohen Gary H.
Published: January 2020

Biologically active herpes simplex virus (HSV)-induced antigens were selectively removed from extracts of infected BHK cells by affinity chromatography by utilizing an insoluble form of concanavalin A (Con A). Soluble extracts of
3
H-glucosamine-labeled, HSV-infected cells were absorbed to a Con A column. Bound material was eluted with α-methyl-
d
-mannoside (αMM) and NaCl. The specific activity of the eluted glycoproteins increased by 10-fold. Two broad groups of viral-induced antigens were isolated from Con A. Group I includes two antigens which bind to Con A by a specific mechanism because the antigens are dissociated by αMM. Group II contains three antigens which bind to Con A but apparently by a nonspecific or electrolytic mechanism. One antigen in group I was identified as the glycoprotein antigen, CP-1, described previously.
SP62, a Viable Mutant of Bacteriophage T4D Defective in Regulation of Phage Enzyme Synthesis
Authors: Wiberg John S. , Mendelsohn Steven , Warner Virginia , Hercules Kathleen , Aldrich Cynthia , Munro Judith L.
Published: January 2020

SP62 is a mutant of bacteriophage T4D that was discovered because it produces fewer phage than the wild type in the presence of 5-fluorodeoxyuridine. In the absence of phage DNA synthesis, SP62 solubilizes host DNA slower than normal; this may explain the sensitivity to 5-fluorodeoxyuridine. In
Escherichia coli
B at 37 C in the absence of drugs, SP62 makes DNA at a normal rate and the kinetics of appearance of phage are nearly normal. Under the same conditions, SP62 produces T4 lysozyme (gene e) at a normal rate until 20 min, but then produces it at twice the normal rate until at least 60 min. It has long been known that, when T4 DNA synthesis is blocked (DNA
−
state) in an otherwise normal infection, the synthesis of a number of early enzymes continues beyond the shutoff time of about 12 min seen in the DNA
+
state, but still stops at about 20 min. We have termed the 12-min shutoff event S1 and the 20-min shutoff event S2. We show here that, in the DNA
+
state, SP62 makes four early enzymes normally, i.e., S1 occurs. However, in the DNA
−
state (where S1 is missing), SP62 continues to make dCTPase (gene 56), dCMP hydroxymethylase (gene 42), and deoxynucleotide kinase (gene 1) for at least an hour; this results in production of up to 13 times the normal level of dCTPase at 60 min after infection, or 6 times the DNA
−
level. We conclude that SP62 is defective in the second shutoff mechanism, S2, for these three enzymes. In contrast, SP62 causes premature cessation of dTMP synthetase production in the DNA
−
state; the result is a twofold underproduction of dTMP synthetase. Autoradiograms of pulse-labeled proteins separated by slab-gel electrophoresis in the presence of sodium dodecyl sulfate show that a number of other T4 early proteins, including the products of genes 45, 46, and rIIA, are synthesized longer than normal by SP62 in the DNA
−
state. Few late proteins are made in the DNA
−
state, but in autoradiograms examining the DNA
+
state there is little or no effect of the SP62 mutation on the synthesis of T4 late or early proteins. Circumstantial evidence is presented favoring a role for the gene of SP62 in translation of certain mRNAs. At very high temperatures (above 43 C) in the absence of drugs, phage production, but not DNA synthesis, is much reduced in SP62 infections relative to wild-type T4 infections; this temperature sensitivity is greater on
E. coli
CR63 than on
E. coli
B. This property has facilitated recognition of the SP62 genotype and aided in complementation testing and genetic mapping. A later publication will provide evidence that SP62 defines a new T4 gene named
regA
, which maps between genes 43 and 62.
Morphogenesis and Ultrastructure of Respiratory Syncytial Virus
Authors: Bächi Thomas , Howe Calderon
Published: January 2020

Respiratory syncytial (RS) virus was grown in Vero cells and fixed for electron microscopy at various stages of maturation. Both filamentous and round or kidney-shaped particles, either with (complete) or without (incomplete) internal structure, were observed. All four morphological forms were identical with respect to their reactivity with ferritin-labeled antibody to RS virus. Freezeetching revealed a structural feature apparently unique for RS virus, namely helical striations around the core on the internal aspect of the envelope. This specific configuration was already detectable during the early stages of viral differentiation of the host cell membrane. Concentration of free virus by zonal ultracentrifugation of culture fluids onto sucrose cushions yielded predominantly filamentous forms up to 10 μm in length.
Antigenic and Biochemical Characterization of the C-type Particle of the Stable Porcine Kidney Cell Line PK-15
Authors: Woods W. A. , Papas T. S. , Hirumi H. , Chirigos M. A.
Published: January 2020

The C-type particles observed by electron microscopy in PK-15 cells were demonstrated to have biochemical and biophysical properties associated with the oncornavirus group: density of 1:16 in a sucrose gradient, 70
S
RNA, and the RNA-dependent DNA polymerase. The group-specific interspecies antigen, gs-3, was not present. Evidence of a latent infection with a porcine parvovirus was also obtained.
Mason-Pfizer Virus Characterization: a Similar Virus in a Human Amniotic Cell Line
Authors: Parks W. P. , Gilden R. V. , Bykovsky A. F. , Miller G. G. , Zhdanov V. M. , Soloviev V. D. , Scolnick E. M.
Published: January 2020

Mason-Pfizer monkey virus (MP-MV) is a RNA virus with an RNA-instructed DNA polymerase first isolated from a rhesus monkey mammary adenocarcinoma in 1970. Until recently, there have been no other isolates. A continuous human amnion cell line, AO, was found to be producing a virus indistinguishable or closely related to the Mason-Pfizer virus as measured by morphological, immunological, and biochemical methods. By thin-section electron microscopy, the extracellular virus particle in AO line is 115 to 130 nm in diameter and has a preformed nucleoid (80 to 90 nm) before budding, properties which are also characteristic of MP-MV. Two proteins of the virus from the AO line were studied. By immunodiffusion, sera which react specifically with MP-MV give a line of identity with virus from the AO line. The AO viral RNA-instructed DNA polymerase purified by phosphocellulose chromatography was specifically inhibited by anti-MP-MV polymerase sera, and the AO cells contained both DNA and RNA sequences related to MP-MV
3
H-DNA. Viruses thus far indistinguishable from MP-MV have also recently been found by others in different human lines, raising again the question of the species of origin of MP-MV. Because the virus in the AO cells cannot be differentiated from MP-MV, we attempted to determine the origin of MP-MV virus by measuring DNA sequences related to MP-MV
3
H-DNA in uninfected human and rhesus monkey cells. The quantity of MP-MV-like DNA sequences in uninfected primate tissues was found to be much lower than the amount of DNA sequences of murine type-B or type-C viruses in uninfected murine tissues. Thus, it was not possible to determine whether the virus produced by AO cells or MP-MV was of human or monkey origin, or both.
Gamma Ray-Induced Small Plaque Mutants of Western Equine Encephalitis Virus
Authors: Simizu B. , Yamazaki S. , Suzuki K. , Terasima T.
Published: January 2020

Small plaque mutants of Western equine encephalitis virus were obtained from the surviving fractions of wild-type virus which was irradiated with gamma rays. The frequency with which small plaque mutants appeared in the surviving fraction increased with the radiation dose. These mutants were not more resistant to radiation than wild-type virus. The growth rate of a mutant, S127, was lower than that of wild-type. Clonally purified mutant virions presented two peaks in a velocity sedimentation profile; peak 1 corresponded to the peak of wild type and peak 2 moved faster than peak 1. Virions of both peaks were infectious and consistently formed small plaques in chicken embryo cells. Virions reisolated from either peak and grown in chicken embryo cells also revealed two peaks in sedimentation analysis. In the electron microscope examination peak 2 proved to consist of giant form particles, each of which contained more than one nucleoid surrounded with a common envelope. Despite this remarkable morphological difference, densities of the wild-type and S127 mutant virions were similar in cesium chloride gradients. The RNAs and proteins of mutant virions could not be distinguished from those of wild type on the basis of size or charge.
Bacteriophage f1 Infection and Colicin Tolerance
Authors: Smilowitz Henry
Published: January 2020

Bacteriophage f1-infected cells are relatively insensitive to a variety of colicins including E1, E2, and K; an f1 gene product is responsible for this insensitivity. A colicin-tolerant mutant cannot grow f1 phage; f1 DNA does not penetrate this mutant properly. One interpretation of these results is that an f1 gene product blocks the penetration of colicins which is necessary for their action, whereas the colicin-tolerant mutation blocks the penetration of colicins as well as phage f1 DNA.
DNA Polymerase in Virions of a Reptilian Type C Virus
Authors: Twardzik Daniel R. , Papas Takis S. , Portugal Frank H.
Published: January 2020

A study was made of the DNA polymerase of reptilian type C virus isolated from Russell's viper spleen cells. Simultaneous detection experiments demonstrated the presence of 70
S
RNA and RNA-dependent DNA polymerase activity in reptilian type C virions. The endogenous activity was dependent on the addition of all four deoxynucleotide triphosphates and demonstrated an absolute requirement for a divalent cation. The reptilian viral DNA polymerase elutes from phosphocellulose at 0.22 M salt. In this respect, it is similar to the avian (avian myeloblastosis virus; AMV) viral enzyme but is different from the mammalian (Rauscher leukemia virus; RLV) viral enzyme which elutes at 0.4 M salt. The molecular weight of the viper DNA polymerase as estimated from glycerol gradient centrifugation is 109,000. It is a smaller enzyme than the AMV DNA polymerase (180,000 daltons) and somewhat larger than the RLV enzyme (70,000 daltons). A comparison of other properties of the type C reptilian DNA polymerase with the enzyme found in other type C oncogenic viruses is made.
Endogenous C-Type Viruses of BALB/c Cells: Frequencies of Spontaneous and Chemical Induction
Authors: Aaronson Stuart A. , Dunn Claire Y.
Published: January 2020

A sensitive biological assay has been developed for studying the frequency of virus induction from mouse cells containing poorly infectious endogenous C-type viruses. A low spontaneous frequency of virus activation of one but not a second endogenous virus of BALB/c cells has been demonstrated. The resistance of BALB/c cells to superinfection by the more inducible virus appears to be absolute, whereas resistance to the other virus is only relative. Thus, the evidence indicates that the BALB/c cell exerts differential effects at two levels of regulation on the expression of its biologically distinguishable endogenous C-type viruses.
Protein Kinase Stimulated by Cyclic GMP in Uninfected and Simian Virus 40-Infected Monkey Kidney Cells
Authors: Tan K. B. , Sokol F.
Published: January 2020

Uninfected African green monkey kidney cells contain a cyclic GMP-stimulated protein kinase. The level or specific activity of the enzyme was not significantly increased after infection of the cells with simian virus 40. This enzyme probably catalyzes the phosphorylation of the structural proteins of the virus.
Detection of Homologous RNA Sequences Among Six Rhabdovirus Genomes
Authors: Repik Patricia , Flamand Anne , Clark H. F. , Obijeski J. F. , Roy P. , Bishop D. H. L.
Published: January 2020

Complete transcripts of the genome of vesicular stomatitis virus Indiana strain have been used to hybridize to virion RNA to determine if there is RNA sequence homology among these viruses. Cellular RNA from cells infected by each of these viruses has also been used for hybridization with the homologous or heterologous virion RNA. The results indicate that there is little exact sequence homology among these viruses.
Enzymatic Radioiodination of the Envelope Proteins of Avian Myeloblastosis Virus
Authors: Fritz Robert B.
Published: January 2020

Purified avian myeloblastosis virus was iodinated by the lactoperoxidase method. Disruption of the labeled virions and chromatography of the viral proteins showed that radioiodine was associated only with the glycoproteins of the viral envelope. Reaction of the radiolabeled virus with antiviral antibody followed by mild detergent treatment and subsequent recovery of immune complexes showed this technique to be useful for the isolation of viral envelope antigens.
Newcastle Disease Virus-Specific RNA: Polyacrylamide Gel Analysis of Single-Stranded RNA and Hybrid Duplexes
Authors: Kaverin Nicolai V. , Varich Natalia L.
Published: January 2020

Newcastle disease virus-specific [
3
H]uridine-labeled 18
S
RNA was resolved by polyacrylamide gel electrophoresis into several components with molecular weights from 450,000 to 840,000. The analysis of 35 and 24
S
virus-specific RNA also revealed several components in each sedimentational class. The conversion of 18
S
RNA into double-stranded form by hybridization with an excess of unlabeled virion RNA improved the resolution in polyacrylamide gels and revealed at least six distinct components. The same six classes of hybrid duplexes were revealed when
32
P-labeled 50
S
virion RNA was hybridized with an excess of 18
S
RNA. The applicability of polyacrylamide gel electrophoresis of hybrid duplexes to the analysis of viral genome structure is discussed.
Molecular Weight Determination of Sendai and Newcastle Disease Virus RNA
Authors: Kolakofsky Daniel , de la Tour Edward Boy , Delius Hajo
Published: January 2020

The molecular weights of Sendai and Newcastle disease virus RNA were estimated by sedimentation in sucrose gradients and by length measurements in the electron microscope under both denaturing and nondenaturing conditions. Sedimentation analyses under denaturing conditions yielded molecular weight estimates of 2.3 × 10
6
to 2.6 × 10
6
, whereas length measurements yielded estimates of 5.2 × 10
6
to 5.6 × 10
6
for both denatured and nondenatured viral RNA. It would appear that the conditions of denaturation used (99% dimethyl sulfoxide at 26 C, and reaction with 1.1 M formaldehyde for 10 min at 60 C) do not equally denature parainfluenza virus RNA and other RNAs, such as cellular rRNA, 45
S
rRNA precursor, and R17 RNA.
Stimulation of Cellular DNA Synthesis by Human Cytomegalovirus
Authors: Jeor Stephen C. St. , Albrecht Thomas B. , Funk Fred D. , Rapp Fred
Published: January 2020

Human cytomegalovirus (CMV) is able to induce cellular DNA synthesis in both permissive (human embryonic lung) and nonpermissive (Vero) cells. The induction of cell DNA synthesis was assayed by the incorporation of [
methyl
-
3
H]thymidine into macromolecules having the buoyant density characteristics of cell DNA. The DNA synthesis induced by CMV infection appears to represent normal semiconservative replication as opposed to repair synthesis. Both strains of CMV tested were capable of inducing cell DNA synthesis. Virus exposed to heat or UV light prior to infection lost the ability to induce DNA synthesis, indicating that a virus-coded function expressed after infection is responsible for stimulation of cell DNA synthesis.
Temperature-Sensitive Virus from
Aedes albopictus
Cells Chronically Infected with Sindbis Virus
Authors: Shenk Thomas E. , Koshelnyk Kathleen A. , Stollar Victor
Published: January 2020

Cultures of
Aedes albopictus
cells persistently infected with wild-type Sindbis virus (SV-W) give rise to small plaque-forming mutants which are also temperature sensitive. These mutants, designated SV-C, are neutralized by antiserum produced against SV-W. Mutant ts clones were isolated from SV-C by plaque purification. After serial undiluted passage in BHK or mosquito cells, each of the clones gave rise to ts
+
revertants which, however, remained mutant with respect to plaque morphology. Nineteen of 20 clones derived from SV-C were RNA
+
, and one was RNA
−
(SV-C-2). The RNA synthesizing activity, once induced in infected cells by SV-C-2, was stable at the nonpermissive temperature (39.5 C). All clones derived from SV-C were inactivated at 60 C much more quickly than was SV-W. It was not possible to demonstrate complementation between any of the SV-C clones.
Disruptive Action of Potassium Phosphotungstate on φT, the Temperate Bacteriophage of
Bacillus megaterium
899a
Authors: Hendry G. S. , Fitz-James P. C.
Published: January 2020

Although untreated φT may be dried on grids without damage, they were disrupted when negatively stained with potassium phosphotungstate. The potassium phosphotungstate reacted with phage suspended in phosphate buffer, and the altered but still-viable phage was disrupted only on drying. Stability of altered phage was not recovered by dialysis against 10
−3
M Mg
2+
.
Proteinaceous Virus-like Particles from an Isolate of
Aspergillus flavus
Authors: Wood H. Alan , Bozarth Robert F. , Adler Jill , Mackenzie Donald W.
Published: January 2020

Virus-like particles were purified from a single nonaflatoxin-producing isolate of
Aspergillus flavus.
The virus-like particles were spherical, measuring 27 to 30 nm in diameter, were electrophoretically homogeneous, and sedimented at approximately 49
S
. The particles had a buoyant density of 1.28 g/cm
3
in CsCl and contained no detectable nucleic acid.
Gene Expression During the Development of Bacteriophage φ29 III. Analysis of Viral-Specific Protein Synthesis with Suppressible Mutants
Authors: McGuire Jeffrey C. , Pène Jacques J. , Barrow-Carraway Joyce
Published: January 2020

Fifty-four suppressible mutants of bacteriophage φ29 have been isolated with a variety of mutagens and assigned to eight complementation groups. Viral-specific protein synthesis in UV light-irradiated, nonsuppressing
Bacillus subtilis
60084 was analyzed with exponential acrylamide gels. Four additional φ29 proteins which were undetected on ordinary acrylamide gels are reported in this paper. Five phage φ29 proteins have been unambiguously assigned to specific cistrons. Two cistrons had pleiotropic effects on viral protein synthesis. Mutants in cistrons I or II were unable to synthesize DNA in nonsuppressing bacteria. Mutants in cistron I were unable to attach viral chromosomes to the host cell membrane, and the protein responsible for this function has been identified. The other viral protein playing a role in phage φ29 DNA synthesis is also identified and assigned to cistron II. Mutants in cistron II can attach viral chromosomes to membrane, but cannot synthesize DNA in nonsuppressing bacteria.
Replication of Measles Virus: Distinct Species of Short Nucleocapsids in Cytoplasmic Extracts of Infected Cells
Authors: Kiley Michael P. , Gray Robert H. , Payne Francis E.
Published: January 2020

Cytoplasmic extracts of Vero cells infected with wild-strain Edmonston measles virus were found to contain two and probably three distinct species of nucleocapsids. Species sedimenting at 200 and 110
S
contained RNA which sedimented at 50 and 16 to 18
S
, respectively. The third nucleocapsid species which sedimented at 170
S
was not present in all experiments and was not characterized in detail. Essentially all 200 and 170
S
, as well as a portion of the 110
S
, nucleocapsids were membrane associated and probably present in part in cell-associated virions. Five of six plaque purified strains derived from wild-type Edmonston virus produced only 200
S
nucleocapsids. One of these five plaque-purified strains subsequently produced both 200 and 110
S
nucleocapsids after being passaged by using undiluted inocula. These results suggest that measles virus may produce distinct classes of defective virus containing short nucleocapsids and subgenomic viral RNA.
In Vitro Repair of UV-Irradiated
Micrococcus luteus
Bacteriophage N1 Transfecting DNA
Authors: Mahler Inga , George Jeanne , Grossman Lawrence
Published: January 2020

Calcium-treated UV-sensitive, host cell reactivation
−
strains of
Micrococcus luteus
are infected with UV-irradiated N1 DNA. In strains lacking UV endonuclease, in vitro treatment of the irradiated DNA results in transfection enhancement.
Cleavage of a Viral Envelope Precursor During the Morphogenesis of Sindbis Virus
Authors: Jones Kenneth J. , Waite Marilynn R. F. , Bose H. R.
Published: January 2020

In cells infected with a temperature-sensitive mutant of Sindbis virus, the cleavage of the precursor to one of the viral envelope proteins does not occur at the nonpermissive temperature. This precursor is found associated with the plasma membrane fraction obtained from the infected cell. Since this is the site at which the virus matures, this finding suggests that during Sindbis virus replication the precursor to the smaller proteins associates with the cell membrane and is then cleaved during the maturation of the virus.
Mutant of Polyoma Virus with Impaired Adsorption to BHK Cells
Authors: Basilico Claudio , DiMayorca Giampiero
Published: January 2020

A mutant of polyoma virus PY235 has an impaired adsorption to guinea pig red blood cells and BHK-21 hamster cells. Adsorption to 3T3 mouse cells is much less inhibited. These altered adsorption properties are responsible for the apparent inability of PY235 to cause cell transformation or hemagglutination.
Activation of the Murine Sarcoma Virus Genome After Infection with the Murine Leukemia Virus as Determined by Cell Agglutination
Authors: Salzberg Samuel , Green Maurice
Published: January 2020

Non-virus-producing NIH/3T3 cells transformed by the murine sarcoma virus are agglutinated by conconavalin A to the same low level as normal NIH/3T3 cells. Infection with the murine leukemia virus greatly increases the agglutination of transformed cells but not that of normal cells. These data suggest that the morphological expression of cell transformation and the surface alterations associated with increased cell agglutination are controlled by the expressions of different sarcoma virus genes.
Poliovirus Infection and Poly(A) Sequences of Cytoplasmic Cellular RNA
Authors: Koschel Klaus
Published: January 2020

The influence of polio infection on Poly(A) sequences of cellular cytoplasmic RNA was investigated. In the presence of guanidine, cellular protein synthesis was still shut off after poliovirus infection, although there was no viral RNA synthesis. The Poly(A) of these cells was unchanged with respect to quantity, size, and linkage to cellular cytoplasmic RNA. This finding strongly suggests that the shut off of cellular protein synthesis is not caused by a change of the Poly(A) sequences of cellular mRNA.
Transcription of DNA from the 70
S
RNA of Rous Sarcoma Virus II. Structure of a 4
S
RNA Primer
Authors: Faras A. J. , Dahlberg J. E. , Sawyer R. C. , Harada F. , Taylor J. M. , Levinson W. E. , Bishop J. M. , Goodman H. M.
Published: January 2020

The 70
S
RNA of Rous sarcoma virus contains 4
S
RNAs which serve as primers for the initiation of DNA synthesis in vitro by the RNA-directed DNA polymerase of the virus. We purified these primers in three different ways—by isolation of the covalent complex between primer and nascent DNA, by differential melting of the 70
S
RNA, and by two-dimensional electrophoresis in polyacrylamide gels. The 4
S
RNAs purified by these procedures were homogeneous and possessed very similar if not identical nucleotide compositions and sequences. The RNAs were approximately 75 nucleotides long, had pG at the 5′ terminus and CpCpA
OH
at the 3′ terminus, and contained a number of minor nucleotides characteristic of tRNA. In contrast to most tRNA's, the primer lacked rTp and contained Gp (Ψp, Ψp, Cp) Gp (possibly in place of the characteristic sequence GprTpΨpCpGp). At least 50% of the 4
S
primers available on 70
S
RNA were utilized in a standard polymerase reaction in vitro.
Induction of P22 Prophage in
Salmonella typhimurium
by Hycanthone
Authors: Shungu Daniel L. , Cook Thomas M.
Published: January 2020

Hycanthone was found to be an inducer of P22 prophage in
Salmonella typhimurium
LT-2(P22).
Electron Microscopy of Viral RNA: Molecular Weight Determination of Bacterial and Animal Virus RNAs
Authors: Chi Yvonne Yuh , Bassel Alix R.
Published: January 2020

A method for preparation of single-stranded RNA for electron microscopy determination of molecular weight is reported. The method uses treatment with formaldehyde at elevated temperatures to remove secondary structure and spreading in a protein monolayer from 50% formamide onto a 50% formamide hypophase. Molecular weights were determined for some bacterial and animal viruses, for which conflicting values had been reported earlier. Molecular weights determined by the method, using
Escherichia coli
large subunit rRNA for a standard (1.1 × 10
6
), are as follows:
E. coli
small subunit rRNA, 0.53 × 10
6
; coliphage f2-RNA, 1.3 × 10
6
; Qβ-RNA, 1.55 × 10
6
; and Newcastle disease virus RNA, 5.78 × 10
6
.
Replication of Bacteriophage ST-1 in
Escherichia coli
Strains Temperature Sensitive in DNA Synthesis
Authors: Bowes J. Michael
Published: January 2020

Bacteriophage ST-1 replication requires DNA polymerase III (
dnaE
) but not DNA polymerases I or II, DNA ligase, or the products of
dnaA, B, or C-D
. It was not certain whether
dnaG
was required. These results differ considerably from those reported for φX-174.
Viral DNA Synthesis in Cells Infected by Temperature-Sensitive Mutants of Simian Virus 40
Authors: Chou Janice Yang , Avila Jesus , Martin Robert G.
Published: January 2020

Temperature-sensitive mutants of simian virus 40 (SV40) have been classified as those that are blocked prior to viral DNA synthesis at the restrictive temperature, “early” mutants, and those harboring a defect later in the replication cycle, “late” mutants. Mutants of the
A
and
D
complementation groups are early, those of the
B
,
C
, and
BC
groups are late. Our results confirm earlier reports that
A
mutants are defective in a function required for the initiation of each round of viral DNA synthesis.
D
mutants, on the other hand, continue viral DNA replication at the restrictive temperature after preincubation at the permissive temperature. The length of time required for
D
function to be expressed at the permissive temperature—after which infection proceeds unabated on shifting of the cultures to the restrictive temperature—is 10 to 20 h. The viral DNA synthesized in
D
mutants under these conditions progresses in normal fashion through replicative intermediate molecules to mature component I and II DNA molecules.
Simple, Quantitative Assay for Both Xenotropic Murine Leukemia and Ecotropic Feline Leukemia Viruses
Authors: Fischinger Peter J. , Blevins Charlotte S. , Nomura Shigeko
Published: January 2020

A cat cell line carrying the genome of a murine sarcoma virus developed discrete foci in linear response to infection with feline leukemia virus or xenotropic murine C-type virus.
Analysis of the In Vitro Product of an RNA-Dependent RNA Polymerase Isolated from Influenza Virus-Infected Cells
Authors: Caliguiri Lawrence A. , Compans Richard W.
Published: January 2020

The products synthesized in vitro by an RNA-dependent RNA polymerase isolated from influenza virus-infected BHK21-F cells were analyzed by velocity sedimentation, annealing techniques, and acrylamide-agarose gel electrophoresis. Approximately 50% of the RNA synthesized in vitro remains associated with the 50 to 70
S
ribonucleoprotein complex containing polymerase activity; the remainder of the RNA polymerase product sediments heterogeneously with a peak at 13
S
. At least 90% of the in vitro product hybridizes with virion RNA. If polypeptides are labeled early in the growth cycle, both the P and NP polypeptides are detected in the ribonucleoprotein complex by acrylamide gel electrophoresis. The results suggest that the polypeptide composition and the products of the cell-associated RNA polymerase are similar to those of the RNA transcriptase associated with influenza virus particles.
In Vitro Synthesis of Adenovirus Core Proteins
Authors: Eron Larry , Wesphal Heiner , Callahan Robert
Published: January 2020

mRNA extracted from polysomes of KB cells at late stages of productive infection with adenovirus type 2 was translated in a cell-free system derived from Krebs II ascites cells. Two of the polypeptides obtained in this reaction corresponded to the adenovirus core protein V and the precursor to core protein VII. The following criteria were used to establish identity between the in vitro products and the virion proteins: comigration during sodium dodecyl sulfatepolyacrylamide gel electrophoresis, cochromatography in sodium dodecyl sulfate-hydroxyapatite, specific immunoprecipitation of the precursor to core protein VII, and tryptic peptide analysis.
Bacillus subtilis
Bacteriophage SP01, SP82, and φe Require Host Lysyl- and Tryptophanyl-tRNA Synthetases for Phage Development
Authors: Racine Francis M. , Steinberg William
Published: January 2020

Infection of
Bacillus subtilis
mutants having temperature-sensitive lysyl- or tryptophanyl-tRNA synthetases with bacteriophage SP01, SP82, or φe indicates that both host enzymes are essential for phage development. No apparent modification of the temperature-sensitive phenotype of the mutant host enzymes occurs during phage infection.
Synthesis of Viral-Specific RNA in Cells Infected with the Parvovirus, Kilham Rat Virus
Authors: Salzman Lois Ann , Redler Bruce
Published: January 2020

We have studied the viral-specific RNA synthesized after infection of a permissive cell line with Kilham rat virus (KRV). The RNA was shown to be virus specific by analysis of its nucleotide base ratios and by hybridization with KRV and cellular DNA. Viral RNA is synthesized as early as 2 h after infection. This viral RNA synthesis occurs before viral progeny DNA synthesis which is initiated at 7 to 8 h after infection. The predominant viral RNA synthesized before and after viral progeny DNA synthesis has a sedimentation coefficient of approximately 18
S
in dimethylsulfoxide-sucrose gradients and a calculated molecular weight of 6.5 × 10
5
to 7.5 × 10
5
. KRV contains a molecule of single-stranded DNA with a molecular weight of approximately 1.6 × 10
6
. If the viral-specific 18
S
RNA is a homogenous species, it would account for 40 to 50% of the viral genome. A small amount of 26
S
viral RNA with a molecular weight of 1.6 × 10
6
to 1.7 × 10
6
can also be detected. If this 26
S
RNA is a single viral-specific entity, it could represent a transcription of the entire KRV genome.
Isolation and Characterization of Prototrophic Mutants of
Escherichia coli
Unable to Support the Intracellular Growth of T7
Authors: Chamberlin Michael
Published: January 2020

Mutants of
E. coli
B/1 were isolated which grew normally but did not permit the intracellular growth of bacteriophage T7. Two classes of mutants were studied in detail (
tsnB
−
and
tsnC
−
). These strains adsorbed T7 normally and were killed by the infection. Synthesis of T7 RNA and of early and late classes of T7 proteins occurred normally after infection. In T7-infected
tsnB
−
cells, T7 DNA synthesis stopped prematurely shortly after its onset, suggesting that the
tsnB
function affects a step in the late phase of T7 DNA replication. Mutants of T7 were isolated (T7β) which could grow on
tsnB
−
cells. In T7-infected
tsnC
−
cells, T7 DNA synthesis was completely blocked, suggesting that the
tsnC
function affects a step in an early phase of T7 DNA replication.
Glycoproteins of Sindbis Virus: Preliminary Characterization of the Oligosaccharides
Authors: Sefton Bartholomew M. , Keegstra Kenneth
Published: January 2020

The carbohydrate content of Sindbis virus was determined by gas chromatographic analysis. The two viral glycoproteins were found to be approximately 8% carbohydrate by weight. Mannose is the sugar present in the largest amount. Smaller amounts of glucosamine, galactose, sialic acid, and fucose were also detected. Each of the two viral glycoproteins appears to contain two structurally unrelated oligosaccharides. Two of the three Sindbis-specific glycoproteins found in infected chick cells were shown to contain short, unfinished oligosaccharides.