bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatty Chains of Different Lipid Classes of Semliki Forest Virus and Host Cell Membranes
Authors: Laine Raili , Kettunen Maija-Liisa , Gahmberg Carl G. , Kääriäinen Leevi , Renkonen Ossi
Published: January 2020

Semliki Forest virus was grown in BHK-21 cells. The major classes of phospho-and glycolipids of the virus were analyzed for the compositions of fatty acids, aldehydes, and sphingosine bases, and the major glycerophospholipids were analyzed for the relative proportions of alkenyl-acyl, alkyl-acyl, and diacyl forms. All viral lipid classes proved to be mixtures of several molecular species. Each class contained a characteristic mixture of fatty chains, which was different in all other classes. All viral lipid classes resembled their counterparts of the host plasma membrane and also those of the endoplasmic reticulum. The gangliosides of the virus and the plasma membrane proved to be similar even at the level of individual molecular species. The number of certain lipid molecules in an average virion was less than the number of the protein molecules.
Studies on Vaccinia Virus-Directed Deoxyribonucleic Acid Polymerase
Authors: Citarella R. V. , Muller R. , Schlabach A. , Weissbach A.
Published: January 2020

A vaccinia-directed deoxyribonucleic acid (DNA) polymerase has been partially purified from the cytoplasmic fractions of virus-infected HeLa cells. The utilization of natural and synthetic templates by this enzyme resembles that of the host cell DNA-dependent DNA polymerases. The vaccinia DNA polymerase cannot copy ribopolymers or ribonucleic acid but is very effective with an “activated” DNA as template. An exonuclease preferring single-stranded DNA as substrate is found in the most highly purified preparations of the enzyme. The molecular weight of the vaccinia DNA polymerase seems to be about 110,000. The viral DNA polymerase is also found to be associated with purified, infected cell nuclei, and this association may be due, at least in part, to nonspecific adsorption of the vaccinia DNA polymerase by nuclei.
Deoxyribonucleic Acid Repair in Bacteriophage T4: Observations on the Roles of the
x
and
v
Genes and of Host Factors
Authors: Mortelmans Kristien , Friedberg Errol C.
Published: January 2020

Studies were carried out to determine the effect of mutation in the host
pol
I gene on survival of ultraviolet (UV)-irradiated bacteriophage T4. Whereas a slightly reduced survival was observed in
Escherichia coli
strain P-3478 (
pol
A
1
) compared to strain W-3110 (
pol
A
+
), no such difference was observed in two strains isogenic except for the
pol
A gene. It was also shown that, whereas bacteriophage T4
x
is sensitive to UV irradiation, X irradiation, and treatment with methyl-methanesulfonate (MMS), phage T4
v
1
is sensitive only to UV irradiation. The survival of damaged phage T4
x
is neither affected by the presence of the
rec
A,
rec
B, or
pol
A mutations in the host, nor is there evidence that phage T4 effects repair of
rec
A or
pol
A mutants previously treated with either UV or MMS.
Structure of the Ribonucleoprotein of Influenza Virus
Authors: Compans Richard W. , Content Jean , Duesberg Peter H.
Published: January 2020

The ribonucleoprotein (RNP) internal components of influenza virus were separated into distinct size classes by sedimentation in glycerol gradients and examined by electron microscopy by using positive staining with uranyl acetate. The large RNP have a peak in length distribution at 90 to 110 nm, the medium, at 60 to 90 nm, and the small, at 30 to 50 nm. These lengths can be correlated with the estimated molecular weights of the ribonucleic acids contained in the various RNP size classes. The RNP structure appears to consist of a strand which is folded back on itself and coiled in a regular double-helical arrangement.
Isolation and Characterization of Bacteriophage T4 Base Plates
Authors: Poglazov B. F. , Rodikova L. P. , Sultanova R. A.
Published: January 2020

A method for isolating bacteriophage T4 base plates from lysates of
Escherichia coli
B cells infected with the ts mutant in gene 19, ts B31 has been developed. By electrophoresis in polyacrylamide gel with sodium dodecyl sulfate the base plates have been shown to contain five to seven protein components with molecular weights of 36,000, 53,000, 66,000, 81,000, 87,000, and probably about 100,000. Electron microscope studies have demonstrated that base plates may occur in two structural states: in the form of hexagons or stars. Star rays and short fibrils are not radial or elongated and are turned sideways at an angle to the radius. Base plates do not complement in vitro with free tail cores isolated after disintegration of particles of the wild-type bacteriophage.
Micrococcal Nuclease Treatment of Bacteriophage Heads Alters the Right-Hand Cohesive End of Lambda Deoxyribonucleic Acid
Authors: Gillin Frances D. , Bode Vernon C.
Published: January 2020

Isolated bacteriophage lambda heads were exposed to micrococcal nuclease prior to addition of the phage tail. The deoxyribonucleic acid (DNA) was extracted from the heads and sheared to half-molecules whose cohesive ends were annealed to normal lambda DNA half-molecules. Melting curves of each of the cohered halves indicated that only the right-hand termini are altered by nuclease treatment.
Reversible Inactivation of the Deoxyribonucleic Acid Polymerase of Rauscher Leukemia Virus
Authors: Tronick Steven R. , Scolnick Edward M. , Parks Wade P.
Published: January 2020

Rauscher leukemia virus deoxyribonucleic acid polymerase is reversibly inactivated by 6
m
guanidine-hydrochloride. Gel filtration in 6
m
guanidine-hydrochloride reveals that the viral deoxyribonucleic acid polymerase consists of a single polypeptide chain of approximately 70,000 molecular weight.
Development of Bacteriophage Alpha II. Dependence on the Host Ribonucleic Acid Polymerase
Authors: Strniste Gary F. , Taylor William D.
Published: January 2020

Measurements of ribonucleic acid (RNA) synthesis using
14
C-uracil uptake in rifampin-sensitive and rifampin-resistant strains of
Bacillus megatherium
were carried out after infection of the bacteria with bacteriophage α. Phage development was inhibited in the former but not the latter strain, showing that α phage development is dependent on the bacterial host RNA polymerase. This dependence exists at all times during eclipse. RNA polymerase extracts showed the same in vitro rifampin sensitivity as the corresponding bacterial strains.
Methylation Pattern of Lambda Deoxyribonucleic Acid
Authors: Hidalgo Cecilia , Nash Howard A.
Published: January 2020

Deoxyribonucleic acid (DNA) extracted from phage λ grown on
Escherichia coli
K-12 strain W4032 had 113 ± 10 5-methylcytosine residues and 215 ± 20 6-methyl adenine residues per genome, as determined by three independent methods. These methylated nucleotides were distributed equally among the two strands of λ DNA. Shearing of double-stranded DNA to half-length fragments revealed a slight deficiency of 5-methyl cytosine in the 55% guanine plus cytosine half. Shearing the DNA to fragments of smaller length showed that the distribution of methylated nucleotides along the double helix was uniform with the exception of an undermethylated fragment arising from the center of the λ DNA molecule. The implication of these results for the function of methylated nucleotides in the λ DNA molecule is discussed.
Transcription and Transport of Virus-Specific Ribonucleic Acids in African Green Monkey Kidney Cells Abortively Infected with Type 2 Adenovirus
Authors: Lucas Joseph J. , Ginsberg Harold S.
Published: January 2020

The techniques of deoxyribonucleic acid-ribonucleic acid (DNA-RNA) hybridization and immunological precipitation were used to compare the synthesis of adenovirus-specific macromolecules in African green monkey kidney (AGMK) cells infected with adenovirus, an abortive infection, and coinfected with both adenovirus and simian virus 40 (SV40), which renders the cells permissive for adenovirus replication. When viral protein synthesis was proceeding at its maximum rate, the incorporation of
14
C-amino acids into adenovirus structural proteins was about 90 times greater in the doubly infected cells than in cells infected only with adenovirus. However, the rates of synthesis of virus-specific ribonucleic acid appeared to be comparable in the two infections at all times measured. A time-dependent increase in the rate of RNA synthesis observed late in the abortive infection was dependent upon the prior replication of viral DNA. Moreover, all virus-specific RNA species that are normally made late in a productive adenovirus infection (i.e., the true late and class II early RNA species) were also detected in the abortive infection. Adenovirus-specific RNA was detected by molecular hybridization in both the cytoplasm and nuclei of abortively infected cells. Comparable amounts of viral RNA were found in the cytoplasmic fractions of AGMK cells infected either with adenovirus or with both adenovirus and SV40. The results of hybridization-inhibition experiments clearly showed that there was a class of virus-specific RNA molecules, representing about 30% of the total, in the nucleus that was not transported to the cytoplasm. This class of RNA was also identified in similar amounts in productively infected human KB cells. The difference in the abilities of cytoplasmic and nuclear RNA to inhibit the hybridization of virus-specific RNA from whole cells was shown not to be due to a difference in the molecular size of the RNA species from the two cell fractions or to the specific loss of a cytoplasmic species during RNA extraction procedures.
Cell Fusion by Canine Distemper Virus-Infected Cells
Authors: Rankin Anne M. , Fisher Linda E. , Bussell Robert H.
Published: January 2020

AV3 cells (continuous human amnion) infected with the Onderstepoort strain of canine distemper virus produced cell fusion within 2 to 5 hr when added to AV3 cell monolayers. An apparent requirement for intact, infected cells was demonstrated by showing that (i) frozen-and-thawed infected cells failed to induce fusion, (ii) infected cells frozen in the presence of glycerol retained their ability to induce fusion, (iii) infected cells subjected to swelling in hypotonic buffer and homogenization lost their ability to fuse cells, and (iv) semipurified and concentrated virus preparations with infectivity titers as high as 10
7.5
mean tissue culture doses per ml failed to induce fusion within 5 hr. Preparations of intact, infected cells had a mean log
10
ratio of infectivity to fusion activity of 3.6. Treatment with beta-propiolactone rendered the active preparations free from detectable infectivity while they retained their ability to cause cell fusion. Cycloheximide did not block the formation of syncytia in assay cells. This type of cell fusion was neutralized by canine distemper virus immune antisera, and measles virus immune sera showed a slight degree of cross-neutralization. Other cell lines, HEp-2, MA 139 (embryonic ferret lung), MA 104 (embryonic rhesus monkey kidney), and Vero (African green monkey kidney) were also susceptible.
Wild-Type Gross Leukemia Virus: Classification of Soluble Antigens (GSA)
Authors: Aoki Tadao , Herberman Ronald B. , Johnson Patricia A. , Liu Margaret , Sturm Macie M.
Published: January 2020

By inhibiting techniques using indirect immunofluorescence tests and indirect immunoelectron microscopy, the G(Gross) soluble antigens (GSA) in the body fluids of AKR and C58 mice, which have a high incidence of spontaneous leukemia, were classified according to the known specificity of G antigens in the murine Gross leukemia system. GSA existing in the plasma of nonleukemic and leukemic AKR mice and in the ascitic fluid of transplanted AKR spontaneous leukemia K36 showed the several specificities corresponding to G cell surface antigens, GCSAa, b, and c, and type-specific and group-specific viral envelope antigens, tsVEA and gsVEA, respectively. However, the plasma of nonleukemic C58 mice lacks GSAc, which can be recognized by the G-typing mouse serum. GSA corresponding to G
IX
antigen was not detected in the body fluids.
Serological Cross-Reactions Between the Hemagglutinin Subunits of H0N1 and H1N1 Influenza Viruses Detected with “Monospecific” Antisera
Authors: Baker Nicola , Stone H. O. , Webster R. G.
Published: January 2020

“Monospecific” antisera to the “fragile” hemaglutinnis of H0N1 (PR8) and H1N1 (FM1) influenza viruses detected an asymmetrical cross-reaction between these two strains that could not be explained by a common neuraminidase.
Selective Replication of Bacteriophage φ29 Deoxyribonucleic Acid in 6-(
p
-Hydroxyphenylazo)-Uracil-Treated
Bacillus subtilis
Authors: Schachtele Charles F. , Reilly Bernard E. , De Sain Carol V. , Whittington Melvin O. , Anderson Dwight L.
Published: January 2020

Phage φ29 deoxyribonucleic acid (DNA) replicated under conditions where semiconservative DNA production in
Bacillus subtilis
host cells was blocked with 6-(
p
-hydroxyphenylazo)-uracil (HPUra). The time of initiation of φ29 DNA replication was not affected by HPUra, and normal quantities of viable phage were produced in the presence of the inhibitor. Studies with conditional lethal mutants of phage φ29 demonstrated the usefulness of HPUra for detection of viral-specific DNA production.
Ligase-Defective Bacteriophage T4 I. Effects on Mutation Rates
Authors: Koch Robert E. , Drake John W.
Published: January 2020

Temperature-sensitive mutations in bacteriophage T4 gene 30 (polynucleotide ligase) were examined for their effects on spontaneous and proflavine-induced frameshift mutagenesis in the
rII
and
ac
(acridine resistance) cistrons. Only small (fourfold or less) effects on mutation rates were observed, even when selection artifacts involving suppression of gene 30 mutations by
rII
mutations were taken into account. The deoxyribonucleic acid ligase gene of T4 therefore appears to be only a minor determinant of frameshift mutation rates. This result is consistent with the particular nature of frameshift mutagenesis in bacteriophage T4.
Penetration of a Bacteriophage into
Bacillus subtilis
: Blockage of Infection by Deoxyribonuclease
Authors: Zsigray Robert M. , Miss Aaron L. , Landman Otto E.
Published: January 2020

Plaquing of a newly isolated phage of
Bacillus subtilis
, phage 41c, is only 2% efficient in agar containing 200 μg of deoxyribonuclease per ml. Timed deoxyribonuclease addition experiments showed that phage development is blocked in 90% of the cells if deoxyribonuclease is present during adsorption (zero-time samples), whereas 10 min after adsorption the enzyme has little effect (10-min samples). The fate of
32
P-deoxyribonucleic acid label of phage 41c in zero-time samples was compared to that in 10-min samples. In both, about 80% of the label remained with the phage-bacterium complex on initial centrifugation. However, four successive washings removed 90% of the
32
P from the zero-time samples but only 25% from the 10-min samples. In both samples, most of the washed-out label was of low molecular weight. When the time course of interruption of infection by blending was compared with interruption by deoxyribonuclease treatment, the two processes exhibited similar kinetics. It is postulated that both processes block injection at the same site, namely, the point of contact between phage tail and cell wall surface. Partitioning of
32
P label during protoplasting of zero-time and 10-min samples was similar to that observed during washing. For the protoplasting experiments, a quantitative method for plaquing protoplasts was developed. A single bacillus made of several cells can give rise to several protoplast plaque-forming units. Strain 41c was the only phage of seven tested to be inhibited by deoxyribonuclease. No other deoxyribonuclease-sensitive phages have been described.
Characterization of Morphologic Revertants of Murine and Avian Sarcoma Virus-Transformed Cells
Authors: Stephenson John R. , Reynolds Roberta K. , Aaronson Stuart A.
Published: January 2020

Morphologic revertants which contain avian or murine sarcoma viruses have previously been isolated at low frequency from clonal lines of transformed mammalian cells. In the present study, these lines have been further characterized. They are indistinguishable from nontransformed parent cell lines with respect to parameters such as saturation density and colony formation in depleted medium or on monolayers of contact-inhibited cells. The rate of glucose uptake had also reverted to normal. The malignant potential of one of the revertant lines was examined and found to be markedly reduced compared to that of the corresponding transformed cells. The differences in the susceptibilities of revertant cells to retransformation by the same or other oncogenic viruses suggest that different cellular genes may be involved in expression of transformation by various tumor viruses.
Chromatographic and Electrophoretic Analysis of Viral Proteins from Hamster and Chicken Cells Transformed by Rous Sarcoma Virus
Authors: Fleissner Erwin , Tress Ellen
Published: January 2020

Several methods have been explored for the detection and characterization of viral proteins from soluble extracts of cells transformed by Rous sarcoma virus (RSV). Viral antigens have been analyzed after gel filtration in several solvents. In addition, immune complexes formed with virus-specific sera have been isolated by agarose gel filtration and by high- or low-speed centrifugation through sucrose solutions. Radioactive proteins from these immune complexes have been analyzed by gel filtration in 6
m
guanidine hydrochloride or by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Comparison with proteins from purified virus indicates the presence of two viral core proteins (gs1 and gs2) in the soluble fraction from virus-producing chicken cells. In the same fraction from RSV-transformed hamster cells (which do not produce virus), three gs proteins (gs1, gs2, and gs3) could be identified. The soluble viral gs proteins are strongly bound to at least two larger polypeptides in cell extracts. These polypeptides do not appear to be viral in origin and have the property of undergoing a time-dependent aggregation in the extracts. One of these cell-derived proteins, which is present in a variety of uninfected cell types, closely resembles actin.
Isolation and Purification of the Envelope Proteins of Newcastle Disease Virus
Authors: Scheid Andreas , Choppin Purnell W.
Published: January 2020

A procedure has been developed for the isolation of Newcastle disease virus (NDV) envelope proteins. The two surface glycoproteins and the non-glycosylated membrane protein were solubilized with 2% Triton X-100 and 1
m
KCl. Removal of the KCl by dialysis yielded by precipitation a pure preparation of the non-glycosylated membrane protein, which is insoluble in solutions of low ionic strength. The soluble fraction consisting of the two glycoproteins possessed full neuraminidase and hemagglutinating activities. The two glycoproteins could be separated by rate zonal sedimentation in a sucrose gradient containing 1% Triton X-100 and 1
m
KCl. Under these conditions, the sedimentation coefficient of the larger glycoprotein, virus protein 1, was 9.3
s
, and that of the smaller, virus protein 2, was 6.1
s.
Both hemagglutinating and neuraminidase activities were associated with virus protein 1; virus protein 2 had neither activity. The results suggest that both activities reside on a single NDV glycoprotein. Similar results were obtained previously with another paramyxovirus, simian virus 5. These findings suggest that the association of hemagglutinating and neuraminidase activities with one glycoprotein is a general property of the paramyxovirus group.
Role of Mitochondria in the Production of RNA-Containing Tumor Viruses
Authors: Bader Artrice V.
Published: January 2020

The role of mitochondria in the reproduction of RNA-containing tumor viruses was examined by using ethidium bromide (EB) to induce degenerative effects in mitochondria. The effects of EB in murine and avian cells were monitored by electron microscopy. Chronically infected mouse (JLS-V5) cells, in which extensive mitochondrial changes were induced, continued to produce murine leukemia virus. Also, complete reproductive cycles of Rous sarcoma virus (RSV) occurred in newly infected chicken embryo cells exposed to EB. Morphological transformation characteristic of infection of chicken embryo cells by RSV occurred in cells which contained induced aberrant mitochondria. The results demonstrate that mitochondria play a relatively minor role, if any, in the reproduction of RNA-containing tumor viruses.
Viral RNAs Associated with Ribosomes in Sindbis Virus-Infected HeLa Cells
Authors: Rosemond H. , Sreevalsan T.
Published: January 2020

Virus specific RNA ribosome complexes were isolated by sucrose density gradient centrifugation of cytoplasmic extracts from HeLa cells infected at 42 C with an RNA
+
mutant (ts2) of Sindbis virus. Viral RNA-ribosome complexes were accumulated by infected cells treated with sodium fluoride and cycloheximide. The RNA-ribosome complexes were characterized by (i) their sensitivity to the action of ribonuclease or ethylenediaminetetraacetic acid, (ii) their density in cesium chloride gradients, and (iii) presence of host ribosomes and viral RNAs. The viral RNAs were isolated and characterized. The results showed that two species of single-stranded RNAs (a 28
s
and 18 to 15
s
species) were associated with the complexes. Base composition analysis of the viral RNAs indicated that both species had a higher adenine content than the 42
s
or 26
s
forms of viral RNAs. The RNAs associated with the ribosome complexes were virus specific since they annealed with denatured double-stranded RNAs from the infected cells. Little or no 42S RNA was associated with the RNA-ribosome complexes. The results suggest that the 28
s
and 18 to 15
s
forms of RNAs may represent viral messenger RNAs.
Metabolic Requirements for the Development of Hemadsorption Activity and Virus Formation in BHK-21 Cells Infected with Newcastle Disease Virus
Authors: Nagai Yoshiyuki
Published: January 2020

Differential effect of various metabolic inhibitors on the development of hemadsorption activity and virus formation in cells infected with Newcastle disease virus (NDV) was investigated. It was found that, in BHK-21 cells infected with NDV, cycloheximide did not prevent the development of hemadsorption activity, whereas protein synthesis and virus formation by the cell were rapidly inhibited by the drug. When the drug was added to the culture at 4.5 h after infection or later, hemadsorption activity of the cell continued to develop normally for about 1 h. Similar increase in hemadsorption activity was found in cells which were treated with anti-NDV serum (to neutralize their hemadsorption activity) and then washed and incubated with cycloheximide. However, when cells were treated with the drug early in the infection (1.5 or 3.0 h), they did not show any detectable hemadsorption reaction throughout the infection. In contrast to cycloheximide, iodoacetate added to the culture together with sodium azide inhibited completely both the development of hemadsorption activity and the formation of progeny virus. These results suggest that the change of cell surface to become hemadsorptive may depend upon the energy generating system but not upon de novo synthesis of protein, whereas production of infectious virus may require continuous synthesis of protein.
Effect of Inhibition of Macromolecule Synthesis on the Association of Bacteriophage T4 DNA with Membrane
Authors: Earhart C. F. , Sauri C. J. , Fletcher Gail , Wulff Judith L.
Published: January 2020

The “Mg
2+
-Sarkosyl crystals” (M band) technique distinguishes between membrane-bound and free intracellular DNA. This procedure was employed to investigate the nature of the reactions necessary to convert input T4 DNA to a rapidly sedimenting form. Energy poisoning inhibits this attachment reaction. Neither protein nor DNA synthesis appears to be required, but experiments with rifampin and extensively irradiated T4 suggest that RNA synthesis is involved. These results were confirmed by a second procedure for the determination of rapidly sedimenting DNA.
Bacteriophage of
Haemophilus influenzae
III. Morphology, DNA Homology, and Immunity Properties of HP1
c
1, S2, and the Defective Bacteriophage from Strain
Rd
Authors: Boling Maxon E. , Allison David P. , Setlow Jane K.
Published: January 2020

The phages HP1
c
1 and S2 and a defective phage of
Haemophilus influenzae
have been compared. The morphology of the phages and the mol wt of their DNAs are similar, although the defective phage appears to have a different tail plate region. Electron microscope observation indicates that the defective phage does not attach to the cell surface, and its DNA appears to lack cohesive ends. The homology of the DNAs of the phages has been measured by hydridization. DNA from the defective phage shows little or no homology with the other phage DNAs. HP1
c
1 and S2 DNAs show a high level of homology. Each of these phages can form plaques on lawns of the lysogen of the other phage but at reduced plating efficiencies, suggesting that the two phages have related but not identical immunity systems.
Growth of Coliphage T7 in
Salmonella typhimurium
Authors: Brunovskis Ilze , Burns R. O.
Published: January 2020

A mutant of
Salmonella typhimurium
was found to be sensitive to killing by coliphage T7 because of an alteration in its surface properties. However, the infections were abortive and studies with
32
P-labeled T7 grown in
Escherichia coli
B (T7·B) indicated that the phage DNA was restricted by
S. typhimurium.
When a mutant T7 which survived the restriction and produced plaques on
Salmonella
(T7·S) was passed through one cycle of growth in
E. coli
B, its ability to grow in
Salmonella
was lost, indicating that host-controlled restriction and modification are operative in this system. Restrictionless
S. typhimurium
mutants were isolated that permit the growth of not only T7·S but also T7·B and coliphage T3. The physiology of T7 production in the restrictionless host is nearly identical to that in
Escherichia coli.
Temperature-Sensitive Simian Virus 40-Transformed Cells: Phenomena Accompanying Transition from the Transformed to the “Normal” State
Authors: Renger Hartmut C. , Basilico Claudio
Published: January 2020

Temperature-sensitive simian virus (SV 40)-transformed 3T3 cells (tsSV3T3), which express the transformed phenotype when growing at 32 C but not at 39 C, were used to study changes in growth behavior during shift-up or shift-down experiments. In cultures of tsSV3T3 cells which had reached or were beyond monolayer density at 32 C, DNA synthesis reached very low levels within 24 to 48 h after shift-up. When cells which had been allowed to grow to high densities at 32 C were shifted to 39 C, not only cell growth stopped, but within two to three days the cultures shed a large number of cells into the medium. These cells were nonviable, and shedding stopped only when the number of cells attached had been reduced to that characteristic of the saturation density at 39 C. The remaining attached cells were viable and after the shift to 32 C were again able to grow from the monolayer to high cell densities. This behavior has been compared with that of normal 3T3 and wild-type SV3T3 cells under different conditions. We have also isolated new tsSV3T3 lines, using cells which had been infected with non-mutagenized wild-type SV40. This further demonstrates that the temperature sensitivity of these lines is due to a cellular rather than a viral mutation.
Structural Rearrangement and Subunit Composition of RNA from Released Soehner-Dmochowski Murine Sarcoma Virions
Authors: East James L. , Allen Patton T. , Knesek John E. , Chan James C. , Bowen James M. , Dmochowski Leon
Published: January 2020

Two types of genomic, high-molecular-weight RNA species were found in Soehner-Dmochowski murine sarcoma virions released from virus-induced rat tumor cells grown in tissue culture. The type of RNA species observed depended on the length of exposure of the tumor cells to radioactive precursor. Early RNA of virions labeled up to 4 h with radioactive uridine had a sedimentation coefficient of 50
S
, and late RNA of virions labeled for 24 h had a sedimentation coefficient of 58
S
. Thermal transitions of early and late RNA indicated a difference in the configuration or structure of these two types of RNA. The late RNA may represent either a different configurational state of the early RNA or an aggregate molecule of two early RNA components joined together. Heat dissociation revealed that the major subunit of both RNA types was a 28
S
species, which was not susceptible to degradation by the addition of micrococcal nuclease to virions. A transitional, intermediate RNA species with a sedimentation coefficient of 37 to 40
S
was detected when early RNA was dissociated by dimethyl sulfoxide or heat at temperatures suboptimal for complete conversion. No free RNA subunit components were detected in virions harvested at intervals as short as 30 s or 5 min. A model for the assembly of genomic RNA from 28
S
RNA subunits is proposed.
Genetic Study of Suppressor-Sensitive Mutants of the
Bacillus subtilis
Bacteriophage φ29
Authors: Reilly Bernard E. , Zeece Viola M. , Anderson Dwight L.
Published: January 2020

With bacteriophage φ29 of
Bacillus subtilis
133, suppressor-sensitive (
sus
) hydroxylamine mutants have been isolated. Intracistronic and intercistronic quantitative complementation placed the mutants in 13 cistrons, and three-factor crosses have been used to assign an unambiguous order for 10 cistrons. Recombination frequencies have been presented for several regions of the genome to facilitate comparison of the
sus
system with the previously published temperature-sensitive mapping systems.
Lack of Sequence Homology Between the 70
S
RNA of Various RNA Tumor Viruses and the DNA of Simian Virus 40 or Polyoma Virus
Authors: Gallagher Robert E. , Levine Arthur S. , Gillespie David H. , Gallo Robert C.
Published: January 2020

No significant hybridization was detected of DNA from simian virus 40 or polyoma virus, and of 70
S
RNA from avian myeloblastosis virus, murine leukemia virus (Rauscher), murine sarcoma virus (Kirsten), RD-114B, simian sarcoma virus-1, or Mason-Pfizer virus.
Replication of Bacteriophage φX174 DNA in a Temperature-Sensitive
dnaE
Mutant of
Escherichia coli
C
Authors: Dumas Lawrence B. , Miller Christine A.
Published: January 2020

Bacteriophage φX174 cannot grow in a temperature-sensitive
dnaE
(DNA polymerase III) mutant of
Escherichia coli
C at the nonpermissive temperature. The inability to grow is the result of inhibition of virus DNA synthesis. The synthesis of the parental replicative form is unaffected, but the replication of the replicative form and the synthesis of the single-stranded virus DNA are inhibited.
Role of Gene 52 in Bacteriophage T4 DNA Synthesis
Authors: Naot Yehudith , Shalitin Channa
Published: January 2020

In an attempt to elucidate the mechanism of delayed DNA synthesis in phage T4,
Escherichia coli
B cells were infected with H17 (an amber mutant defective in gene 52 possessing a “DNA-delay” phenotype). The fate of
14
C-labeled H17 parental DNA after infection was followed: we could show that this DNA sediments more slowly in neutral sucrose than wild-type DNA 3 min postinfection. In pulse-chase experiments progeny DNA was found to undergo detachment from the membrane at 12 min postinfection. Reattachment to the membrane was found to be related to an increase in rate of DNA synthesis. A nucleolytic activity that is absent from cells infected by wild-type phage and from uninfected cells could be detected in extracts prepared from mutant-infected cells. In contrast, degradation of host DNA was found to be less extensive in
am
H17 compared with wild-type infected cells. Addition of chloramphenicol to mutant-infected cells 10 min postinfection inhibited the appearance of a nuclease activity on one hand and suppressed the “DNA-delay” phenotype on the other hand. We conclude that the gene 52 product controls the activity of a nuclease in infected cells whose main function may be specific strand nicking in association with DNA replication. This gene product might directly attack both
E. coli
and phage T4 DNA, or indirectly determine their sensitivity to degradation by another nuclease.
Injection of Ultraviolet-Damage-Specific Enzyme by T4 Bacteriophage
Authors: Shames Rose B. , Lorkiewicz Zbigniew K. , Kozinski Andrzej W.
Published: January 2020

When UV-irradiated T4 bacteriophage (v
+
) infects in the presence of chloramphenicol, the phage DNA rapidly acquires single-stranded breaks proportional to the dose of UV. In contrast, when UV-irradiated T4 v
1
(radiation sensitive mutant) infects under identical conditions, the phage DNA remains integral. A series of coinfections with v
+
and v
1
phage (UV-v
1
+ majority non-UV-v
+
and UV-v
+
and majority non-UV-v
1
) show that the enzyme responsible for breakage is injected by the phage. It is also demonstrated that the v
1
phage injects an inactive enzyme that delays breakage by the v
+
enzyme and interferes with subsequent repair. The cross of v
+
and v
1
phage produces mixed progeny that contain both active and inactive enzyme in a single capsid. The possible function of this breaking enzyme, necessitating injection of multiple copies, is considered.
Some Bacteriophages Active Against
Rhizobium trifolii
Strain W19
Authors: Atkins Gregory J.
Published: January 2020

Fourteen soil bacteriophages active against
Rhizobium trifolii
W19 have been studied which fall into four structural groups. Group 1 phages have contractile tails. Some particles show double base plates to which at least three spikes are attached, and fibers are attached to the base plates. Group 2 phages also have contractile tails. At least five spikes are attached to the base plate, and there are spherical bodies adjacent to the tail, at the ends of fibers attached to the tail base. Group 3 phages have contractile tails, but are larger than phages of groups 1 and 2. The end of the tail has a complex structure. Group 4 phages have long, noncontractile tails.

Phages c and I of group 1 and phages a and e of group 2 were chosen for further study. Single-step growth curves were plotted, and absorption constants were measured. The classification into groups was confirmed by using antiserum inactivation. Susceptibility of phage-resistant mutants of
R. trifolii
W19 to these bacteriophages was determined.
Regulation of Early mRNA Synthesis in Bacteriophage T4-Infected Bacteria: Dependence on Bacteriophage-Specific Protein Synthesis
Authors: Bolund Christina , Sköld Ola
Published: January 2020

The mechanism of the transcriptional turn-off was studied for those species of mRNA in T4 infection which specify early phage proteins. Total synthesis of these early RNA species was determined by short-time labeling with uracil-
5
-
3
H
after the infection of
Escherichia coli
B with DNA-negative, conditional lethal mutants, which produce no late mRNA under nonpermissive conditions. With both amber and temperature-sensitive mutants a decrease in incorporation into early RNA by more than 90% was observed within 15 min after infection. Analysis by thin-layer chromatography showed uracil-
5
-
3
H
to enter nucleotide pools throughout the infection cycle. The observed decrease in early RNA synthesis was dependent on protein synthesis, since it could be prevented by chloramphenicol. By varying the time of chloramphenicol addition, the effect of this regulatory protein(s) was found to appear at 3 to 4 min and reached its full extent at 10 to 15 min after infection. The turn-off of transcription of a defined early gene was studied by 5-fluorouracil (FU) rescue of an early, DNA-negative, amber mutant (gene 1, deoxynucleotide kinase) at different times after infection. DNA synthesis could be rescued by FU addition early after infection, but not after 12 min. 5-fluorouracil was efficiently taken up into the nucleotide pools also at late times, as shown by thin-layer chromatography. After incubation in the presence of chloramphenicol from 3 min after infection, DNA synthesis could be rescued as late as 45 min after infection. Thus, when protein synthesis was blocked during the early period of infection, the shut-off of transcription of the studied early gene was prevented.
Synthesis of Bacteriophage φ29 Proteins in
Bacillus subtilis
Authors: Pène Jacques J. , Murr Peter C. , Barrow-Carraway Joyce
Published: January 2020

Seventeen bacteriophage φ29 proteins were detected in ultraviolet light-irradiated
Bacillus subtilis
by autoradiography of polyacrylamide slab gels. The appearance of φ29 proteins occurred either before or concomitantly with viral DNA replication. Viral proteins detected early in the infectious cycle consisted of nine polypeptides ranging from 5,200 daltons to 54,000 daltons. Two of the early proteins were identified as, respectively, the major capsid protein and the protein comprising the filaments which extend from the head of the virus. Late φ29 proteins were composed of eight polypeptides ranging from 14,000 daltons to 95,000 daltons. Only three late proteins were noncapsid proteins. Among the early proteins, six were synthesized at diminishing rates late in the infectious cycle. One of the early proteins (protein 12) lacked histidine, whereas two (proteins 10 and 15) lacked tryptophan. Among the 17 proteins detected, 10 were viral noncapsid proteins. The amount of viral genetic information required to code for the 17 proteins detected in these experiments (81% of the potential genetic information of φ29 DNA) compares favorably with the genetic information detected as mRNA in a previous report, 85% of the potential information on the φ29 chromosome.
Genetic Map of Bacteriophage T3
Authors: Beier Hildburg , Hausmann Rudolf
Published: January 2020

About 200 amber mutants of phage T3 were found to lie in 14 different genes. These genes are homologous to known T7 genes. The genetic map of T3 is very similar to that of T7.
Lack of Serological Relationship Among DNA Polymerases of Avian Leukosis-Sarcoma Viruses, Reticuloendotheliosis Viruses, and Chicken Cells
Authors: Mizutani Satoshi , Temin Howard M.
Published: January 2020

Antibodies against a large and a small DNA polymerase isolated from chicken embryos and against avian myeloblastosis virus DNA polymerase were used to study the serological relationships of the DNA polymerase activities of three avian systems with RNA and a DNA polymerase—avian leukosis-sarcoma viruses, reticuloendotheliosis viruses, and a fraction from uninfected chicken cells. The DNA polymerase activity of disrupted virions of all avian leukosis-sarcoma viruses tested was neutralized to the same extent by antibody against avian myeloblastosis virus DNA polymerase and was not neutralized by the antibodies against chicken cellular DNA polymerases. The viruses tested included induced leukosis viruses and Rous-associated virus-O. The DNA polymerase activity of disrupted virions of all of the reticuloendotheliosis viruses was not neutralized by any of the antibodies. The chicken endogenous RNA-directed DNA polymerase activity was neutralized partially or completely, in different experiments, by antibody against the small DNA polymerase isolated from chicken embryos, but was not neutralized by the other two antibodies.
Studies on the Nucleic Acid Sequences of Kirsten Sarcoma Virus: a Model for Formation of a Mammalian RNA-Containing Sarcoma Virus
Authors: Scolnick Edward M. , Rands Elaine , Williams David , Parks Wade P.
Published: January 2020

The genetic information contained in the Kirsten and Moloney strains of mammalian RNA-containing sarcoma viruses has been analyzed by RNA ·
3
H-DNA hybridization. Kirsten sarcoma virus has been found to possess two distinct sets of nucleic acid sequences. One set of sequences is contained in murine type C helper virus, and the other set is contained in rat type C helper virus. Moloney sarcoma virus contains sequences of murine type C helper virus but not of rat type C helper virus. The results indicate that Kirsten sarcoma virus arose through a process of recombination between Kirsten murine leukemia virus and nucleic acid sequences found in rat cells. A model is suggested for the formation of transforming type C viruses involving the transduction of oncogenic information.
RNA Polymerase Activity Associated with Bacteriophage φ6
Authors: Van Etten J. L. , Vidaver A. K. , Koski R. K. , Semancik J. S.
Published: January 2020

The
Pseudomonas phaseolicola
bacteriophage φ6 incorporated labeled UTP into an acid-insoluble precipitate. Incorporation was dependent on the presence of manganese acetate, ATP, GTP, CTP, and a short heat treatment of the phage; the reaction was stimulated by NH
4
Cl. The substitution of
14
C-ATP, -CTP or -GTP for UTP, together with the appropriate unlabeled ribonucleoside triphosphates, disclosed that CMP was incorporated to the greatest extent followed by GMP, UMP, and AMP. Radioactive RNAs formed by the reaction were resistant to RNases A and T
1
in high salt but susceptible to these nucleases in low salt. The labeled RNA co-sedimented and co-electrophoresed with φ6 double-stranded (ds) RNA. However, the distribution of the radioactivity into the three ds-RNA components varied depending on the
14
C-ribonucleoside triphosphate used in the reaction. The incorporation of UMP was primarily into the two smaller ds-RNA segments, GMP primarily into the large ds-RNA segment, and CMP and AMP were about equally distributed into all three ds-RNA segments.
Temperature-Sensitive Defect of Mutants Isolated from L Cells Persistently Infected with Newcastle Disease Virus
Authors: Preble Olivia T. , Youngner Julius S.
Published: January 2020

The temperature-sensitive defects of virus mutants isolated from L cells persistently infected with Newcastle disease virus (NDV) were analyzed. Genetic grouping of the mutants by complementation tests was attempted by using several different methods, including yield analysis, RNA synthesis, and heterozygote formation at 42 to 43 C, the nonpermissive temperature. In each case, specific interference prevented detection of complementation. This interference was shown to occur prior to or at the level of virus RNA synthesis. Temperature-shift experiments with five different NDV
pi
clones showed that virus replication begun at 37 C could not be completed at the nonpermissive temperature. The activity of the NDV-specific RNA-dependent RNA polymerase in the cytoplasm of infected chicken embryo cells was not stable and could not be demonstrated directly. However, indirect measurement of RNA polymerase activity at the nonpermissive temperature was accomplished by studying the kinetics of virus-specific RNA synthesis in infected cells after temperature shift. Two types of response were obtained: with three NDV
pi
clones, virus-specific RNA synthesis ceased immediately upon transfer of infected cells to 42 to 43 C, whereas in cells infected with two other NDV
pi
clones, RNA synthesis continued for several hours at this temperature. These results suggested that there may be two types of ts defects in NDV
pi
, both associated with virus-specific RNA polymerase activity.
Human Papovavirus, BK Strain: Biological Studies Including Antigenic Relationship to Simian Virus 40
Authors: Takemoto Kenneth K. , Mullarkey Michael F.
Published: January 2020

Some of the properties of a new human papovavirus, BK, have been examined. Host range studies of BK virus (BKV) showed human cells to be more sensitive to infection than monkey cells; human fetal brain cells appear to be highly sensitive to BKV, with the production of extensive cytopathology characterized by cytoplasmic vacuolization. The hemagglutinin of BKV is associated with the virion and is resistant to ether or heating at 56 C for 30 min. Fluorescent antibody as well as neutralization tests indicated antigenic similarities between simian virus 40 (SV40) and BKV. Cells undergoing lytic infection with BKV synthesized intranuclear T antigen(s) which reacted with SV40 T antibody demonstrable by immunofluorescence. However, BKV did not appear to induce SV40 transplantation antigens in transplantation-resistance tests. Evidence was obtained that BKV was present in humans prior to the widespread use of polio vaccines, thus ruling out the possibility that BKV is an SV40-related monkey virus, introduced into the human population by accidental contamination of poliovirus vaccines.
Intracellular Forms of Adenovirus DNA II. Isolation in Dye-Buoyant Density Gradients of a DNA-RNA Complex from KB Cells Infected with Adenovirus Type 2
Authors: Doerfler Walter , Lundholm Ulla , Rensing Ute , Philipson Lennart
Published: January 2020

DNA-RNA complexes with different DNA/RNA ratios have been isolated from KB cells productively infected with human adenovirus type 2 by the dye-buoyant density procedure by using propidium iodide. Both the DNA and RNA components of these complexes are virus specific, and parental as well as newly synthesized viral DNA can be recovered from these complexes. The RNA component is susceptible to digestion with pancreatic ribonuclease at low and high salt concentrations. The RNA is in part liberated from the complex during purification over several cycles of equilibrium centrifugation in dye-buoyant density and Cs
2
SO
4
gradients. Analysis in the latter gradients reveals at least four classes of virus-specific nucleic acid: (i) RNA loosely bound and released during purification, (ii) and (iii) two distinct classes of RNA-DNA complexes with different DNA/RNA ratios, and (iv) DNA apparently not associated with RNA. The size of the RNA molecules is large but varying in the different classes of complexes. The biological function of these complexes is still uncertain, but they may be transcription complexes.
Polypeptide Composition of Influenza B Viruses and Enzymes Associated with the Purified Virus Particles
Authors: Oxford J. S.
Published: January 2020

Influenza B/LEE/40, B/Rome/1/67, B/Hong Kong/8/73, and B/Victoria/98926/70 viruses have a similar polypeptide composition as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These viruses are composed of six or seven polypeptides, depending on whether one or two high-molecular-weight polypeptides are resolved, ranging in molecular weights from 27,000 to 90,400. Three of these polypeptides, namely the heavy and light hemagglutinin chains and the neuraminidase, have attached carbohydrate. Highly purified influenza B/LEE/40 and B/Rome/1/67 virus preparations have RNA-dependent RNA polymerase activity equivalent to the incorporation of 100 and 30 pmol, respectively, of
3
H-UMP per mg of virus protein per h at 37 C, which is demonstrated only in detergent-treated virus suspensions. However, no RNA-dependent DNA polymerase enzyme activity was detected in the two viruses although virus suspensions were “activated” by heat, α-chymotrypsin, and detergents. Other enzymatic activities were associated with purified preparations of influenza B virus and were attributed to minor contamination of virus with host cell enzymes. Thus, nucleoside and deoxynucleoside phosphohydrolase enzymes were active in the absence of detergents and catalyzed the release of 1,200 and 1,800 nmol of P
i
per mg of virus protein in 30 min at 37 C from ATP and dATP substrates. Thin-layer chromatography indicated that the products of the phosphohydrolase enzymes of influenza B/LEE/40 were mainly nucleoside diphosphate and monophosphate. The latter enzymes were tightly bound to influenza B/LEE/40 virus and could not be removed completely by repeated centrifugation, including centrifugation of the virus to equilibrium in density gradients of 25 to 40% (wt/vol) cesium chloride. A low degree of RNase (approximately 0.01 μg% contamination) and phosphatase (10-30 nmol of P
i
released per mg of virus protein per 30 min) activity was detected in some, but not all, influenza B/LEE/40 virus preparations.