bluuebunny/crossref_metadata_2025 huggingface dataset:
Herpes Simplex Virus and Human Cytomegalovirus Replication in WI-38 Cells I. Sequence of Viral Replication
Authors: Smith Janet Duyckinck , de Harven Etienne
Published: January 2020

A comparison, under standardized conditions, of herpes simplex virus (HSV) and human cytomegalovirus (CMV) revealed differences in viral morphology, in the timing of their infectious cycles, and in several morphological events during those cycles. Structural distinctions between the two viruses included the coating of unenveloped cytoplasmic CMV capsids, but not those of HSV, and a variation in the structure of their cores. Since the two cycles were carried out in the same host cell strain under conditions of one-step growth (input multiplicity = 10 PFU/cell), it was possible to construct time scales locating the major events of each cycle. Comparison of the two showed that HSV replicated and released progeny within 8 h postinfection, whereas CMV required 4 days. These results correlated well with those of concurrent plaque assays. Within the longer CMV cycle, most of the major events appeared retarded to a similar degree, and no obvious limiting step in particle production could be identified. Distinctions between the two cycles included the following: condensation of the chromatin in HSV- but not CMV-infected cells; the greater tendency of HSV to produce membrane alterations; and the appearance of cytoplasmic dense bodies in CMV- but not HSV-infected cells. Identification of these differences even under identical conditions of culture and infection strongly implies that they result from intrinsic differences in the nature of the viruses, and are not caused by variations in experimental conditions.
Structural Characteristics and Nucleotide Sequence Analysis of Genomic RNA from RD-114 Virus and Feline RNA Tumor Viruses
Authors: East James L. , Knesek John E. , Allen Patton T. , Dmochowski Leon
Published: January 2020

The results of molecular hybridization experiments have demonstrated that the RNA genome of RD-114 virus has extensive nucleotide sequence homology with the RNA genome of Crandell virus, an endogenous type C virus of cats, but only limited homology with the RNA genomes of feline sarcoma virus and feline leukemia virus. The genomic RNAs of RD-114 virus and Crandell virus also had identical sedimentation coefficients of 50
S
. A structural rearrangement of genomic RNA did not exist within released RD-114 virions, whereas a structural rearrangement of genomic RNA did occur within feline sarcoma virions and feline leukemia virions after release from virus-producing cells.
Replication of Bacteriophage SH-133 in the Facultative Autotroph
Hydrogenomonas facilis
II. Bacteriophage Synthesis and Hydrogenase Induction Under Step-Up and Step-Down Growth Conditions
Authors: Aron Gary M. , Pootjes Christine F.
Published: January 2020

Autotrophically grown infected cells are able to replicate phage SH-133 after being switched to a heterotrophic environment (step-up growth). The effect of step-down growth on phage replication varies with the choice of organic substrate. Phage replication and the induction of cellular hydrogenase occur under step-down growth from acetate but not peptone broth. The requirement of a continued source of energy for phage replication in either heterotrophically or autotrophically grown cells could be uniquely demonstrated in this phage-host system by the deletion of hydrogen from the growth medium.
L Protein Requirement for In Vitro RNA Synthesis by Vesicular Stomatitis Virus
Authors: Emerson Suzanne U. , Wagner Robert R.
Published: January 2020

The endogenous transcriptase present in purified vesicular stomatitis (VS) virions was solubilized with a Triton X-100 high-salt solution. The polymerase activity was purified on glycerol gradients and by phosphocellulose column chromatography; the viral proteins present in the active enzyme fractions were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was demonstrated that L protein, but not NS protein, was required for in vitro RNA synthesis on the VS viral nucleocapsid template. Solubilized L protein rebinds to the ribonucleoprotein template when the transcription complex is reconstituted, and the RNA synthesized in vitro by purified L protein hybridizes to virion RNA. Cyanogen bromide peptide fingerprints indicate that the large L protein is a unique polypeptide chain. It is concluded that the L protein functions as the transcriptase, and the nucleocapsid NS protein is not essential for in vitro RNA synthesis.
RNA Synthesis of Vesicular Stomatitis Virus V. INTERACTIONS BETWEEN TRANSCRIPTION AND REPLICATION
Authors: Perlman Stanley M. , Huang Alice S.
Published: January 2020

The temperature-sensitive mutant
ts
114 of vesicular stomatitis virus is temperature-sensitive in both primary and secondary transcription, but not in the replication of 40
S
RNA. The synthesis of 40
S
RNA is specifically inhibited when protein synthesis is shut off. The addition of cycloheximide to cells infected by
ts
114, rapidly inhibits RNA replication at the permissive and nonpermissive temperatures. However, the addition of cycloheximide at the nonpermissive temperature also results in almost complete recovery of transcription to the level found at the permissive temperature. Other inhibitors of protein synthesis applied at the nonpermissive temperature result in the same recoverability of the apparent temperature-sensitive lesion. Ribonucleic acid products synthesized by
ts
114 at the nonpermissive temperature in the presence of cycloheximide are identical to virus-specific messenger RNA by the criteria of size and complementarity to virion RNA. When mutant-infected cells are shifted to the nonpermissive temperature, incubated for a period of time, and then treated with cycloheximide, the ratio of transcriptive to replicative activity varies depending on the time at which radioactive precursor is added to cells. This suggests an interdependence between replication and transcription during virus-specific RNA synthesis.
Some Properties of the PBP1 Transduction System in
Bacillus pumilus
Authors: Lovett P. S. , Bramucci D. , Bramucci M. G. , Burdick B. D.
Published: January 2020

Bacteriophage PBP1 is a flagella-specific virus that performs generalized transduction in strains of
Bacillus pumilus.
PBP1 is morphologically and serologically distinct from two other flagella-specific phages, PBS1 and SP-15, which perform generalized transduction in certain
Bacillus
species. The DNA extracted from PBP1 particles has a buoyant density of 1.690 g/cm
3
in cesium chloride gradients, a melting temperature of 86.1 C, and a sedimentation velocity of 47
S
in neutral sucrose gradients. Assuming the molecule is a linear duplex, PBP1 DNA has a molecular weight of approximately 76 × 10
6
. In two strains of
B. pumilus
which are sensitive to both PBP1 and PBS1, co-transducible genetic markers are more tightly linked by PBS1 transduction than by PBP1 transduction. The size of the fragment of bacterial DNA carried by PBP1-transducing particles, inferred from transduction studies and sedimentation analysis of viral DNA, suggests that PBP1 may be useful for genetic studies of extrachromosomal DNA elements present in two strains of
B. pumilus.
Genetic exchange of chromosomally located genes between the plasmid
+
and plasmid
-
B. pumilus
strains NRS 576 and NRRL B-3275 has been demonstrated by PBP1 transduction.
Regulation of Expression of Late Genes of Bacteriophage T5
Authors: Chinnadurai G. , McCorquodale D. J.
Published: January 2020

Amber mutants of bacteriophage T5 defective in gene C2 have been characterized. The product of this gene is required for the normal turn-on of synthesis of late RNA's and proteins, and, apparently, for the normal continued synthesis of early RNA's and proteins during late stages of infection. The inability of nonpermissive cells to synthesize any proteins, either late or early, during the late period after infection with a C2-mutant is not due to premature lysis of the infected cells, to a depletion of the cellular energy supply, or to degradation of phage DNA at late times. A possible role for the product of gene C2 in early and late transcription of the viral genome is suggested.
Acquisition of New DNA Sequences After Infection of Chicken Cells with Avian Myeloblastosis Virus
Authors: Shoyab M. , Baluda M. A. , Evans R.
Published: January 2020

DNA-RNA hybridization studies between 70
S
RNA from avian myeloblastosis virus (AMV) and an excess of DNA from (i) AMV-induced leukemic chicken myeloblasts or (ii) a mixture of normal and of congenitally infected K-137 chicken embryos producing avian leukosis viruses revealed the presence of fast- and slow-hybridizing virus-specific DNA sequences. However, the leukemic cells contained twice the level of AMV-specific DNA sequences observed in normal chicken embryonic cells. The fast-reacting sequences were two to three times more numerous in leukemic DNA than in DNA from the mixed embryos. The slow-reacting sequences had a reiteration frequency of approximately 9 and 6, in the two respective systems. Both the fast- and the slow-reacting DNA sequences in leukemic cells exhibited a higher
T

m

(2 C) than the respective DNA sequences in normal cells. In normal and leukemic cells the slow hybrid sequences appeared to have a
T

m

which was 2 C higher than that of the fast hybrid sequences. Individual non-virus-producing chicken embryos, either group-specific antigen positive or negative, contained 40 to 100 copies of the fast sequences and 2 to 6 copies of the slowly hybridizing sequences per cell genome. Normal rat cells did not contain DNA that hybridized with AMV RNA, whereas non-virus-producing rat cells transformed by B-77 avian sarcoma virus contained only the slowly reacting sequences. The results demonstrate that leukemic cells transformed by AMV contain new AMV-specific DNA sequences which were not present before infection.
Primate and Murine Type-C Viral Nucleic Acid Association Kinetics: Analysis of Model Systems and Natural Tissues
Authors: Scolnick E. M. , Parks W. , Kawakami T. , Kohne Dave , Okabe H. , Gilden Ray , Hatanaka M.
Published: January 2020

Hybridization studies employing single-stranded
3
H-DNA transcripts of type-C viruses isolated from a woolly monkey or gibbon ape failed to detect nucleic acid sequences homologous to these viruses in the DNA from a variety of uninfected primate species. The possible significance of these results for the epidemiology of type-C viruses in primates is discussed.
Detection of Naturally Occurring Antibodies to RNA-Dependent DNA Polymerase of Murine Leukemia Virus in Kidney Eluates of AKR Mice
Authors: Hollis V. W. , Aoki T. , Barrera O. , Oldstone M. B. A. , Dixon F. J.
Published: January 2020

Specific antibodies to the RNA-dependent DNA polymerase (reverse transcriptase) of murine type C viruses have been isolated from the renal glomeruli of both leukemic and nonleukemic AKR mice where they presumably had been deposited as immune complexes. The antibodies were shown to have sedimentation coefficients of 26
S
to 28
S
and 5
S
to 7
S
on sucrose rate zonal centrifugation. Inactivation with monospecific antisera to various mouse immunoglobulins identified antibodies as being in both immunoglobulin (IGM) and IgG classes. In addition, these antibodies only reacted with the reverse transcriptase from murine and feline type C viruses, but not the polymerase from avian myeloblastosis virus (AMV). Our results provide additional evidence for the lack of immunological tolerance and demonstrate the presence of another immune complex system in AKR kidneys.
Interferon Induction in Rabbit Cells Irradiated with UV Light
Authors: Mozes Lee W. , Vilček Jan
Published: January 2020

UV irradiation of a continuous line of rabbit kidney cells (RK13) was used as a tool for the study of the mechanism of interferon induction. Irradiation of cells prior to their exposure to Newcastle disease virus (NDV) resulted in a dose-dependent decrease in interferon production. The inhibition of total cellular RNA synthesis by UV irradiation in uninduced cultures was similar to the inactivation curve of interferon production in NDV-induced cultures. In contrast, the production of interferon with polyinosinate-polycytidylate (poly[I]·poly [C]) paradoxically was enhanced in cells irradiated with a wide range of doses of UV. However, in cells stimulated with poly(I)·poly(C) and “superinduced” by the sequential addition of cycloheximide and actinomycin D, the rate of inactivation of interferon production by UV light was similar to that observed with NDV. These results are not inconsistent with the idea that both poly(I)·poly(C) and NDV stimulate the same interferon gene(s), but indicate that the mechanism controlling its expression may be different for each inducer.
Effect of Ultraviolet Light on Mengovirus: Formation of Uracil Dimers, Instability and Degradation of Capsid, and Covalent Linkage of Protein to Viral RNA
Authors: Miller Richard L. , Plagemann Peter G. W.
Published: January 2020

UV irradiation of purified mengovirus resulted in a very rapid inactivation of the infectivity of the virions (D
37
[37% survival dose] = 700 ergs/mm
2
) which correlated in time with the formation of uracil dimers in the viral RNA. During the first 2 min of irradiation, an average of 1.7 uracil dimers were formed per PFU of virus inactivated. Hemagglutination activity of the virions began to decrease only after a lag period of about 5 min and at a much lower rate (D
37
= 84,000 ergs/mm
2
). This decrease coincided in time with the appearance of altered proteins in the capsid and a structural change in the capsid. Although 10- to 20-min irradiated virions appeared intact in the electron microscope and sedimented at 150
S
in sucrose density gradients, the RNA of the virions became accessible to RNase and extractable by low concentrations of sodium dodecyl sulfate, and the virions broke down upon equilibrium centrifugation in CsCl gradients. During longer periods of irradiation (30 to 60 min), a progressively greater proportion of the virions were converted to 14
S
protein particles and 80
S
ribonucleoprotein particles composed of intact viral RNA and about 30% of the capsid proteins, alpha, beta, and gamma. Empty capsids were not detectable at any time during 60 min of irradiation, by which time disruption of the virions was complete. Irradiation of complete virions also resulted in an increased sedimentation rate of the viral RNA and in the covalent linkage to the viral RNA of about 1% of the total capsid protein in the form of heterogeneous low-molecular-weight polypeptides. The two observations seem to be causally related, since irradiation of isolated viral RNA did not result in an increase in sedimentation rate of the RNA, even though uracil dimer formation in viral RNA occurred at about the same rate and to the same extent whether intact virions or viral RNA were irradiated.
Fragmentation of RNA in Virus Particles of Rhinovirus Type 14
Authors: Gauntt C. J.
Published: January 2020

Purified particles of rhinovirus type 14 lose infectivity during incubation at 34.5 C as a result of fragmentation of RNA genomes within intact virions.
Transcription of DNA from the 70
S
RNA of Rous Sarcoma Virus I. Identification of a Specific 4
S
RNA Which Serves as Primer
Authors: Dahlberg J. E. , Sawyer R. C. , Taylor J. M. , Faras A. J. , Levinson W. E. , Goodman H. M. , Bishop J. M.
Published: January 2020

The enzymatic transcription of DNA from the 70
S
RNA of Rous sarcoma virus (RSV) is initiated on the 3′ terminus of a molecule of 4
S
RNA which is hydrogen bonded to the viral genome. We labeled this primer with radioactive deoxynucleotides, and demonstrated that its release from 70
S
RNA by thermal denaturation was accompanied by a reduction in the template activity of the viral RNA. Two-dimensional electrophoresis in polyacrylamide gels separated the 4
S
RNAs associated with the 70
S
RNA of RSV into approximately eight fractions, each of which appeared to contain a discrete species of tRNA. The RNA in one of these fractions served as the principal primer for initiation of DNA synthesis by both detergent-disrupted virions of RSV and purified RNA-directed DNA polymerase with RSV 70
S
RNA as template.
Intracellular Forms of Adenovirus DNA III. Integration of the DNA of Adenovirus Type 2 into Host DNA in Productively Infected Cells
Authors: Burger Harold , Doerfler Walter
Published: January 2020

KB cells productively infected with human adenovirus type 2 contain an alkalistable class of viral DNA sedimenting in a broad zone between 50 and 90
S
as compared to 34
S
for virion DNA. This type of DNA is characterized as viral by DNA-DNA hybridization. It is extremely sensitive to shear fragmentation. Extensive control experiments demonstrate that the fast-sedimenting viral DNA is not due to artifactual drag of viral DNA mechanically trapped in cellular DNA or to association of viral DNA with protein or RNA. Furthermore, the fast-sedimenting DNA is found after infection with multiplicities between 1 and 1,000 PFU/cell and from 6 to 8 h postinfection until very late in infection (24 h). Analysis in dye-buoyant density gradients eliminates the possibility that the fast-sedimenting viral DNA represents supercoiled circular molecules. Upon equilibrium centrifugation in alkaline CsCl density gradients, the fast-sedimenting viral DNA bands in a density stratum intermediate between that of cellular and viral DNA. In contrast, the 34
S
virion DNA isolated and treated in the same manner as the fast-sedimenting DNA cobands with viral marker DNA. After ultrasonic treatment of the fast-sedimenting viral DNA, it shifts to the density positions of viral DNA and to a lesser extent to that of cellular DNA. The evidence presented here demonstrates that the 50 to 90
S
viral DNA represents adenovirus DNA covalently integrated into cell DNA.
Harvey Sarcoma Virus: A Second Murine Type C Sarcoma Virus with Rat Genetic Information
Authors: Scolnick Edward M. , Parks Wade P.
Published: January 2020

The nucleic acid sequences found in the Harvey strain of murine sarcoma virus have been analyzed by RNA·[
3
H]DNA and [
3
H]RNA·DNA hybridization techniques. The Harvey strain of murine sarcoma virus has been found to possess at least two sets of nucleic acid sequences. One set of sequences is contained in the Moloney strain of mouse type-C virus, and the other set is contained in DNA transcripts synthesized in endogenous reactions containing rat type-C virus(es). The nucleic acid sequences that are detected in the Harvey sarcoma virus with the DNA probes synthesized from the rat type-C virus(es) are related to the rat sequences detected in the Kirsten strain of murine sarcoma virus. The results support the model that both Kirsten and Harvey sarcoma viruses arose through a process of recombination or reassortment between mouse type-C viruses and sequences in rat cells and suggest that the information for transformation of fibroblasts may be contained in the rat type-C or cellular genome.
Conditional Lethal Mutants of Adenovirus 2-Simian Virus 40 Hybrids I. Host Range Mutants of Ad2
+
ND1
Authors: Grodzicker Terri , Anderson Carl , Sharp Phillip A. , Sambrook Joe
Published: January 2020

Human adenovirus type 2 (Ad2) grows poorly in monkey cells, although this defect can be overcome by co-infection with simian virus 40 (SV40). The nondefective Ad2-SV40 hybrid virus, Ad2
+
ND1, replicates efficiently in both human and African green monkey kidney cells, presumably due to the insertion of SV40 sequences into the Ad2 DNA. Several mutants of Ad2
+
ND1 have been isolated that grow and plaque poorly in monkey cells, although they retain the ability to replicate and plaque efficiently in HeLa cells. One of these mutants (H39) has been examined in detail. Studies comparing the DNA of the mutant with Ad2
+
ND1 either by the cleavage patterns produced by
Escherichia coli
R·RI restriction endonuclease digestion or by heteroduplexing reveal no differences. The pattern of protein synthesis of Ad2
+
ND1 and H39 in monkey cells is quite different with the mutant resembling Ad2, which is defective in the synthesis of late proteins. However, in human cells, the proteins synthesized by H39 and the parent Ad2
+
ND1 are very similar. The production of SV40 U antigen in H39-infected cells is different from that in Ad2
+
ND1-infected cells. Finally, the growth of H39 in monkey cells can be complemented by SV40.
Nonreplicated DNA and DNA Fragments in T4 r
−
Bacteriophage Particles: Phenotypic Mixing of a Phage Protein
Authors: Carlson K. , Kozinski A. W.
Published: January 2020

“Conservative phage” containing a genome derived from an infecting phage particle which has not undergone replication in the cell but nevertheless has become encapsulated and released in a normal phage particle, are found after infection of
Escherichia coli
with rII
−
or rI
−
mutants under conditions which result in rapid lysis. If such conservative phage are derived from a mixed infection with v
+
and v
1
phage, they display phenotypic mixing of the v gene product (an endonuclease carried in the phage particle). Populations of rI and rII mutant phage grown under conditions of rapid lysis include particles containing short DNA fragments. It is suggested that a “maturation defect”, common to rI and rII mutants, but absent in rIII mutants, may account for the encapsulation of nonreplicated DNA as well as that of the DNA fragments.
Homologous Viral Interference in Trout and Atlantic Salmon Cell Cultures Infected with Infectious Pancreatic Necrosis Virus
Authors: Nicholson Bruce L. , Dunn James
Published: January 2020

The occurrence of homologous interference in the replication of infectious pancreatic necrosis virus was demonstrated after successive passages of partially purified virus at high input multiplicities in trout and Atlantic salmon cell cultures. Pretreatment of cell cultures with interfering virus inhibited the replication of homologous standard infectious virus but not unrelated viruses. The ability of infectious pancreatic interfering virus to interfere with homologous virus was abolished with UV irradiation, immune serum, and freeze-thawing.
Effect of Protein A on Adsorption of Bacteriophages to
Staphylococcus aureus
Authors: Nordström Kristina , Forsgren Arne
Published: January 2020

Experiments were performed to determine if protein A influenced the association of bacteriophages with
Staphylococcus aureus
. Bacteriophage adsorption was compared in a
S. aureus
strain rich in protein A and mutants of this strain with very little protein A, in a strain with little protein A, and in mutants of this strain with increased protein A. In addition, the effect of growth in mannitol-salt broth and trypsin digestion (known to reduce protein A) on bacteriophage absorption was measured. There was an inverse relationship between protein A content of strains and the quantity of bacteriophage absorbed. However, no inhibition of staphylococcal phages was obtained with purified soluble protein A. Protein A as a surface component rendered the bacteria more resistant to adsorption of staphylococcal typing phages presumably by masking the phage receptor sites. When protein A-deficient mutants were incubated with bacteriophages, there was survival of staphylococci with increased protein A content probably due to a selective action.
Point Mutants in the D2a Region of Bacteriophage T4 Fail to Induce T4 Endonuclease IV
Authors: Vetter D. , Sadowski P. D.
Published: January 2020

We have studied the properties of presumptive point mutants in the D2a region of bacteriophage T4. Dominance tests showed that the D2a mutation was recessive to the wild-type allele. The mutations were shown to map in the D2a region by complementation against
r
II deletions. The D2a mutations were also located between gene 52 and
r
IIB by two- and three-factor crosses. The mutants are located at at least two distinct loci in the D2a region. The point mutants grow normally on all hosts tested and none of the mutants makes T4 endonuclease IV. We propose the name “
den
B” for the D2a locus.
Marine Transducing Bacteriophage Attacking a Luminous Bacterium
Authors: Keynan Alex , Nealson Kenneth , Sideropoulos Henry , Hastings J. W.
Published: January 2020

The isolation and partial characterization of a marine bacteriophage attacking a strain of luminous bacteria is described, including some physical, biological, and genetic properties. It is a DNA phage of density of 1.52 with a long flexible tail and an apparently icosohedral head. With respect to stability in suspension, it has a rather specific requirement for the sodium ion in high concentration; it is further stabilized by the addition of calcium and magnesium ions. These same ions are likewise all required for both good plating efficiency and plaque uniformity. Although it goes through a typical lytic growth cycle (about 45 min), with a burst size of 100, and no stable lysogens have been isolated, it is nevertheless a transducing phage specifically for the tryptophan region, transducing several, but not all, independently isolated Trp
−
auxotrophs to protrophy. No other auxotrophs of a variety of amino acids were transduced by this phage to prototrophy. Phage infection does not change the normal expression of the luminescent system, and light remains at near normal levels until cell lysis occurs.
Immunological Cross-Reactions Between Two Low-Molecular-Weight Polypeptides from A Murine Type C Virus
Authors: Parks Wade P. , Scolnick Edward M , Noon Marian C. , Watson Cynthia J.
Published: January 2020

Two low-molecular-weight type-specific virion polypeptides from the Kirsten strain of Murine leukemia virus, polypeptides p10 and p12, are immunologically related by radioimmunoassay competition techniques.
Transcribing Complexes in Cells Infected by Vesicular Stomatitis Virus and Rabies Virus
Authors: Villarreal Louis Perez , Holland John J.
Published: January 2020

We analyzed cell extracts from BHK
21
cells infected with vesicular stomatitis virus (VSV) and rabies virus for in vitro RNA polymerase activity. Cells infected with VSV B virions exhibited several complexes with in vitro RNA polymerase activity in sucrose gradients. These complexes synthesize VSV transcriptase product (4 to 18
S
) polyadenylated in RNA complementary to virion RNA. Cells infected with a high multiplicity of B virions and T particles show only one RNA polymerase complex active in vitro. This complex sediments at 110
S
and makes only small (2
S
) RNA. Carrier BHK
21
cells persistently noncytopathically infected with VSV contain several complexes active in RNA polymerase, but both exhibit very low activity. Cytoplasms of cells noncytopathically infected with rabies virus also show very low levels of a complex containing RNA polymerase activity. No transcriptase nor any other in vitro polymerase activity could be found associated with purified rabies virions, although they do carry out primary transcription in cells treated with actinomycin D and cycloheximide before infection.
Temperature-Sensitive Mutants of Adenovirus Type 12 Defective in Viral DNA Synthesis
Authors: Ledinko Nada
Published: January 2020

Ten temperature-sensitive (ts) mutants of adenovirus type 12 which produce plaques at 31 but not at 38.5 C have been isolated after mutagenesis with nitrosoguanidine or nitrous acid. The mutants have been classified into six separate complementation groups. DNA-DNA hybridizations have shown that at 38.5 C the ts 401 and 406 mutants of groups B and E, respectively, synthesized less than 10% of the normal level of viral DNA. The two mutants were also defective in the production of late proteins at the nonpermissive temperature, as shown by fluorescent-antibody tests and analysis by sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Genetic recombination between the ts viruses 401 and 406 has been demonstrated; the recombination frequency for the wild-type virus production was 17.7%. Both mutants induced an increase in thymidine kinase activity at 38.5 C. Moreover, the two viral DNA-defective mutants shut off host DNA synthesis at the restrictive temperature. It is striking that at 38.5 C ts virus 401 transformed two to eight times more hamster cells than the wild-type virus, whereas ts virus 406 transformed at a frequency similar to the wild-type virus.
Cold Lability of
Bacillus cereus
Bacteriophage CP-51
Authors: Thorne Curtis B. , Holt Stanley C.
Published: January 2020

Phage CP-51 was rapidly inactivated when stored at the usual refrigerator temperatures (2 to 4 C) and even more rapidly when exposed to 0 C. The loss in viability resulting from exposure to cold appeared to correlate with the increase in number of phage particles having contracted tails. High concentrations (0.01 M) of Mg
2+
, Ca
2+
, or Mn
2+
stabilized the phage considerably, but even in the presence of these divalent cations, it was much less stable at 0 C than at 15 C.
Time Course of Synthesis and Assembly of Influenza Virus Proteins
Authors: Meier-Ewert Herbert , Compans Richard W.
Published: January 2020

The synthesis of viral polypeptides was analyzed in BHK-21-F cells infected with the WSN strain of influenza virus at various times in the growth cycle. The relative amounts of polypeptides P, HA, NP, and NS did not change markedly between early and late times in the growth cycle; however, there was a progressive increase in the relative amount of the M polypeptide at later time points. In cell fractionation experiments, the patterns of newly synthesized polypeptides associated with various cytoplasmic fractions remained similar throughout the growth cycle except for an increase in polypeptide M in all fractions late in the growth cycle. The HA polypeptide was chased out of cytoplasmic membranes completely 6 h after synthesis, whereas the M polypeptide was not chased effectively from such membranes. Marked differences were found in the incorporation into mature virions of polypeptides synthesized at different times in the growth cycle. Polypeptides P and NP synthesized at early times were incorporated preferentially, whereas M was synthesized and incorporated predominantly late in the growth cycle. The fact that the rates of incorporation of polypeptides into virions differed significantly from their rates of synthesis indicates that different polypeptides were assembled into virions by distinct pathways.
Properties of
Corynebacterium acnes
Bacteriophage and Description of an Interference Phenomenon
Authors: Zierdt Charles H.
Published: January 2020

Nine virulent bacteriophages of the anaerobe
Corynebacterium (Propionibacterium) acnes
, the P-a series, are DNA phages, with long, curved nonretractile tails (130 nm) without tail plates or fibers. They have isometric heads (420 by 460 nm), and are placed in Bradley's group B-1. There is permanent plaque suppression at highest phage concentrations. After 100- to 1,000-fold dilution, plaques are evident. The latent period is 1 h and burst size 25. Cross-neutralization data of antisera for the nine phages are similar. There is an unexplained precipitous drop in plaque-forming units during the first 5 min of neutralization, after which the rate is linear for 2 h. They are sensitive to pH extremes but are partially protected even at pH 4 or 9 by storage at 4 C. They are resistant to ether and chloroform and are inactivated within 10 min at 70 C.
Bacteriophage PBS2-Induced Deoxycytidine Triphosphate Deaminase in
Bacillus subtilis
Authors: Price Alan R.
Published: January 2020

The dCTP deaminase induced by
Bacillus subtilis
bacteriophage PBS2, whose DNA contains uracil instead of thymine, requires metal ion and thiol activators and has a molecular weight of 125,000. The enzyme displays sigmoidal substrate saturation kinetics and inhibition by dUTP, consistent with the deaminase's proposed role of providing balanced levels of dUTP and dCTP for PBS2 uracil-DNA synthesis.
Transduction in
Bacillus subtilis
by Bacteriophage SPP1
Authors: Yasbin Ronald E. , Young Frank E.
Published: January 2020

Lysates of the virulent bacteriophage SPP1 were shown to be capable of mediating generalized transduction. Suppressible mutants of this bacteriophage (
sus
) were capable of transduction at a lower multiplicity of infection than virulent SPP1. Linkage analysis demonstrated that bacteriophage SPP1 transduced segments of the genome equal in size to that transferred by SP10. This bacteriophage should be useful in analyzing the regions of the genome where PBS1 appears to give anomalous results.
Accumulation of Incomplete Particles After UV-Light Induction of
Haemophilus influenzae
Lysogenic for Bacteriophage HP1c1
Authors: Okinaka Richard T. , Barnhart Benjamin J.
Published: January 2020

Temperate phage HP1c1 produces large quantities of incomplete phage-like particles when grown on
Haemophilus influenzae
BC200, a strain apparently cured of a common defective prophage.
Virus envelope markers in mammalian tropism of avian RNA tumor viruses
Authors: Boettiger D , Love D N , Weiss R A
Published: January 2020

Pseudotypes of vesicular stomatitis virus were prepared with avian sarcoma viruses and avian leukemia viruses representing five different subgroups. These pseudotypes display a host range restricted to that of the avian tumor virus when assayed on avian cells and are neutralized by subgroup-specific antisera. The efficiency of penetration of mammalian cells was assayed by using these vesicular stomatitis virus pseudotypes. Pseudotypes of avian tumor viruses belonging to subgroup D and of B77 virus were able to plate on mammalian cells with a high efficiency, whereas pseudotypes of other strains were not. The efficiency of penetration of the vesicular stomatitis virus pseudotypes was 10-2-to 10-3-fold higher than the efficiency of transformation of the corresponding avian tumor virus strain assayed on mammalian cells, suggesting that there are postpenetration blocks to the expression of transformation in these cells.
Studies on reverse transcriptase of RNA tumor viruses. I. Localization of thermolabile DNA polymerase and RNase H activities on one polypeptide
Authors: Verma I M
Published: January 2020

Purified reverse transcriptase from avian myeloblastosis virus or Rous sarcoma virus consists of two subunits of average mol wt of 100,000 and 60,000. The lower-molecular-weight subunit, alpha, has been isolated from avian myeloblastosis virus, Rous sarcoma virus and a temperature-sensitive mutant of Rous sarcoma virus, LA337. Subunit alpha manifests both the DNA polymerase and RNase H activities associated with purified reverse transcriptase of avian RNA tumor viruses. The thermal inactivation of these enzymatic activities of alpha subunit from the wild-type virus. The results show that both DNA polymerase and RNase H activities associated with the alpha subunit of LA337 are five to seven times more thermolabile then the corresponding alpha subunit from the wild-type virus. It is concluded that (i) both the polymerase and nuclease activities reside on the same polypeptide chain, and (ii) at least the lower-molecular-weight subunit alpha is coded for by the viral RNA.
Replication of polyoma DNA in isolated nuclei. V. Complementation of in vitro DNA replication
Authors: Otto B , Reichard P
Published: January 2020

Nuclei from polyoma-infected 3T6 fibroblasts elongate in vitro the progeny strands of the replicative intermediates of polyoma DNA. When high concentrations of such nuclei were incubated, short DNA fragments were formed and subsequently added onto growing progeny strands. When nuclei were repeatedly washed with buffer containing detergent and then incubated at low concentrations. DNA synthesis was decreased. In particular, the joining process was reduced, resulting in an accumulation of short DNA fragments. All aspects of the synthetic capacity of the nuclei were restored by addition of cytoplasmic extract. Additions of purified enzymes (polynucleotide ligase from calf thymus or Escherichia coli together with E. coli DNA polymerase I) increased the joining function of the nuclei. The system can be used for the identification of the enzymatic steps concerned with polyoma DNA replication.
Genetic transmission of endogenous N- and B-tropic murine leukemia viruses in low-leukemic strain C57BL/6
Authors: Odaka T
Published: January 2020

Spontaneous expression of endogenous N- and B-tropic murine leukemia viruses was stu1bb), DDD (Fuv-1nn), DDD-Fvr (fv-1nn), (DDD or DDD-Fvr times C57BL/6)F1, and 16 partially inbredlines with either the Fv-1nn or Fv-1bb genotype, which had been established from hybrids between C57BL/6 and DDD-Fvr. When tested at middle age, virus-positive mice were found in C57BL/6, F1 hybrids, and 9 out of 16 partially inbred lines. N-tropic viruses were isolated from Fv-1nn, Fv-1bb mice, whereas B-tropic viruses, except for one isolate, were from Fv-1bb mice only. C57BL/6 mice were positive for both N- and B-tropic viruses, whereas DDD-Fvr mice were negative. With respect to the Fv-1 genotype and the presence of endogenous murine leukemia viruses, the partially inbred lines were grouped into five types: (i) Fv-1bb, both N- and B-tropic virus positive, like C57BL/6; (ii) Fv-1nn, virus negative, like DDD-Fvr; (iii) Fv-1bb, virus negative; (iv) Fv-1nn, only N-tropic virus positive; and (v) less convincingly, Fv-1bb, only B-tropic virus positive. These findings indicate that the transmission of N- and B-tropic viruses in C57BL/6 is genetically controlled and that the expression of B-tropic virus, but not of N-tropic virus, is closely associated with the Fv-1 genotype.
Malignant transformation of hamster kidney cells by BK virus
Authors: Portolani M , Barbanti-Brodano G , Placa M L
Published: January 2020

Primary hamster kidney cells were transformed by BK virus, a new human papovavirus. Transformed (HKBK) cell produced BK virus T antigen and induced tumors in hamsters that developed antibodies to BK virus T antigen. BK virus was rescued from HKBK cells by Sendai virus-assisted fusion with permissive cells. One out of six cell lines derived from HKBK cell-induced tumors showed the same characteristics as HKBK cells.
Effect of fatty acids on growth of Japanese encephalitis virus cultivated in BHK-21 cells and phospholipid metabolism of the infected cells
Authors: Makino S , Jenkin H M
Published: January 2020

Growth of Japanese encephalitis virus (JEV) in BHK-21 cells was stimulated in the presence of 20 to 40 mug of the sodium salt of oleic acid (cis-9-octadecenoic acid, 9-18:1) per ml supplemented in Waymouth medium. The stimulatory effect of the salt was highest when 9-18:1 was added after adsorption of the virus. Study of the effect of other fatty acids on growth of JEV showed the following results: the longer the chain length of the saturated fatty acid salt, the higher the stimulatory effect on viral growth. In contrast, polyunsaturated fatty acids had an inhibitory effect on viral growth. The effect of isomeric cis-octadecenoic acids on viral growth was variable, depending upon the position of the double bond. The cis-6-octadecenoic acid had the highest inhibitory effect on growth of JEV compared to other isomeric octadecenoic acids. The sodium salt of (1-14C) cis-9-octadecenoic acid (9-18:1, 20 mug/ml) was rapidly incorporated into control and JEV-infected cells. Specific radioactivity in phosphatidylcholine dropped 12 to 24 h after virus inoculation, whereas synthesis of phosphatidylethanolamine increased 12 to 24 h after virus inoculation in infected cells compared to uninfected cells. Results from these studies suggest that phospholipid metabolism of infected cells is markedly changed, which can be associated with altered fatty acid metabolism when using labeled 9-18:1 fatty acid as a marker.
Isolation of two subgroup-specific leukemogenic viruses from standard avian myeloblastosis virus
Authors: Ishizaki R , Langlois A J , Bolognesi D P
Published: January 2020

Two populations of virus having subgroup-specific homogeneity (A and B) were isolated from standard avian myeloblastosis virus stocks by passage in vivo through genetically defined chickens. Each possesses leukemogenic activity in vivo. Other properties and potential usefulness of these agents are discussed.
Blocked and Unblocked 5′ Termini in Reovirus Genome RNA
Authors: Chow Nang-Ly , Shatkin Aaron J.
Published: January 2020

Uniformly
32
P-labeled, double-stranded genome RNA isolated from purified reovirus contains two types of 5′-terminal sequences. One strand contains a phosphatase-resistant 5′-terminal structure, XpppG
*
pCpU, which is also present in the viral mRNA. The 5′ blocking group, X, is removed by β-elimination indicating that it is a nucleoside containing free 2′,3′-hydroxyls. G
*
pC is an alkaline-resistant, 2′-
O
-methylated sequence. The other strand contains a phosphatase-sensitive 5′ sequence, ppGpPupPyp. The results are discussed in relation to blocked 5′-terminal structures in other viral and cellular RNAs.
Quantitation of avian RNA tumor virus reverse transcriptase by radioimmunoassay
Authors: Panet A , Baltimore D , Hanafusa T
Published: January 2020

A radioimmunoassay was developed that can detect and quantitate 3 ng or more of the avian RNA tumor virus reverse transcriptase. The assay detected no antigenic sites in Rous sarcoma virus alpha virions or in virions of a murine RNA tumor virus. About 70 molecules of reverse transcriptase were found per virion of avian myleloblastosis virus with this assay or with an assay based on antibody inhibition of enzymatic activity. The assay detected about 270 ng of enzyme per mg of cell protein in virus-producing cells; uninfected cells had much less antigenic material but contained some determinants able to displace radioactive antigen. No additional antigenic determinants on reverse transcriptase could be detected that were not found on the separated alpha subunit of the enzyme. Although sevenfold less sensitive than enzymatic activity as a measure of reverse transcriptase, the radioimmunoassay can detect antigen using small amounts of protein and in the presence of inhibtors.
Isolation and characterization of temperature-sensitive mutants of measles virus
Authors: Bergholz C M , Kiley M P , Payne F E
Published: January 2020

Nine temperature-sensitive (ts) mutants of nonattenuated Edmonston strain measles virus were isolated from wild-type virus which was grown in the presence of 5-fluorouracil. Adsorption, temperature shift, and complementation experiments indicated that all these mutants were restricted at an intracellular stage of infection. However, all the mutants were more rapidly inactivated at 41 C than was wild-type virus, suggesting that the ts product of each mutant either influences or is a structural component of the virus. Three complementation groups were found to be represented among the mutants. Group A contained one mutant and it did not induce synthesis of detectable amounts of viral antigen at the nonpermissive temperature (39 C). Group B consisted of six mutants which did not induce viral antigen synthesis at 39 C and one mutant which did. Group C was represented by one mutant and it induced viral antigen synthesis at 39 C. The two mutants which induced sythesis of viral antigen also induced synthesis of relatively small amounts of virus-specific RNA at 39 C. These mutants, while producing cytoplasmic and nuclear accumulations of viral antigen at 39 C, were restricted in production of syncytia and hemadsorption. All the mutants were less neurovirulent than wild-type virus, as indicated by their inability to produce acute disease in newborn hamsters.
Analysis of antigenic determinants of structural polypeptides of avian type C tumor viruses
Authors: Stephenson J R , Smith E J , Crittenden L B , Aaronson S A
Published: January 2020

Radioimmunoassays were developed for the 19,000, 15,000, and 12,000 molecular weight polypeptides of avian myeloblastosis virus and for the 19,000 and 12,000 polypeptides of RAV-0, a subgroup E avian tumor virus. Each polypeptide was shown to possess both group- and type-specific antigenic determinants, in contrast to the 27,000 mol wt polypeptide, which contained only group-specific determinants. The corresponding low-molecular-weight polypeptides of subgroup A, B, and E viruses were shown to be immunologically indistinguishable. The findings that low-molecular-weight polypeptides of subgroup C and D viruses reacted very differently in immunoassays for the respective polypeptides of avian myeloblastosis virus or RAV-0 suggest that subgroups C and D may have evolved differently form subgroups A, B, and E.
Chromatographic separation and antigenic analysis of proteins of the oncornaviruses. V. Identification of a new murine viral protein, p15(E)
Authors: Ikeda H , Hardy W , Tress E , Fleissner E
Published: January 2020

Profiling of murine leukemia virus (MuLV) proteins by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) has revealed a low-molecular-weight protein which does not appear in the corresponding region of viral protein profiles obtained by gel filtration in 6 M guanidine hydrochloride. This protein species, termed p15(E), is easily demonstrable in MuLV isolates for which the viral p15 and p12 proteins have almost identical electrophoretic mobilities; this leaves a protein slightly larger than these two in the PAGE system unaccounted for in the gel filtration system. However, antiserum against the void volume fraction of the gel filtration eluate precipitated the p15(E) component from solubilized, radiolabeled virions, as shown by SDS-PAGE analysis of such immunoprecipitates. Comparative radioprecipitation analyses of this type revealed that for various MuLV isolates p15(E) was distinguishable from p15 in terms of serological reactivities, relative mobilities in gel electrophoresis, and relative efficiencies of labeling with individual amino acids. Thus it appears that, as is the case for avian oncornaviruses, MuLVs contain seven major structural proteins.
Reaction of poliovirus RNAs with antibodies to double-stranded RNA demonstrated by an immunochemical binding assay
Authors: Miller J R , Calliguiri L A , Tamm J
Published: January 2020

An immunochemical binding assay was used to investigate the reactivity of radioactively labeled viral RNAs from poliovirus-infected cells with antibodies to the synthetic double-stranded RNA, poly(I)-poly(C). A RNase-free antibody-containing serum fraction was employed. Poliovirus replicative form reacted with the antibodies to poly(I)-poly(C) as well as or better than poly(I)-poly(C). Poliovirus replicative intermediate reacted with the antibodies to a greater extent than poliovirus single-stranded RNA, but both were less reactive than replicative form. The use of the immunochemical binding assay with sucrose-gradient fractions demonstrated that for both poliovirus single-stranded RNA and replicative form the peak of reactivity with the antibodies was coincident with the peak of radioactive material precipitated by trichloroacetic acid. The proportion of replicative intermediate that reacted with the antibody increased in sucrose-gradient fractions containing the more slowly sedimenting RI RNA.
Human cytomegalovirus. III. Virus-induced DNA polymerase
Authors: Huang E S
Published: January 2020

Infection of WI-38 human fibroblasts with human cytomegalovirus (CMV) led to the stimulation of host cell DNA polymerase synthesis and induction of a novel virus-specific DNA polymerase. This cytomegalovirus-induced DNA polymerase was purified and separated from host cell enzymes by DEAE-cellulose and phosphocellulose column chromatographies. It can be distinguished from host cell enzymes by chromatographic behavior, template primer specificity, sedimentation property, and the requirement of salt for maximal activity. This virus-induced enzyme has a sedimentation coefficient of 9.2S and is found in both the nuclei and cytoplasm of virus-infected cells, but not in uninfected cells. This enzyme could efficiently use activated calf-thymus DNA, oly(dA)-oligo(dT)12-18, and poly(dC)-oligo(dG)12-18 as template primers, especially poly(dA)-oligo(dT)12-18, but it could not use poly(rA)-oligo(dT)12-18, poly(rC)-oligo(dG)12-18, or oligo(dT)12-18. The enzyme requires Mg2+ for maximal activity, is sensitive to p-hydroxymercuribenzoate, and is not a zinc metalloenzyme. In addition, the cytomegalovirus-induced DNA polymerase activity can be enhanced by adding 0.06 to 0.12 M NaCl or 0.03 to 0.06 M (NH4)2SO4 to the reaction mixture.