bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcription map for adenovirus type 12 DNA
Authors: Smiley J R , Mak S
Published: January 2020

The regions of the adenovirus type 12 genome which encode l- and r-strand-specific cytoplasmic RNA were mapped by the following procedure. Radioactive, intact, separated complementary strands of the viral genome were hybridized to saturating amounts of unlabeled late cytoplasmic RNA. The segments of each DNA strand complementary to the RNA were then purified by S1 nuclease digestion of the hybrids. The arrangement of the coding regions of each strand was deduced from the pattern of hybridization of these probes to unlabeled viral DNA fragments produced by digestion with EcoRI, BamHI, and HindIII.. The resulting map is similar, if not identical, to that of adenovirus type 2. The subset of the late cytoplasmic RNA sequences which are expressed at early times were located on the map by hybridizing labeled, early cytoplasmic RNA to both unlabeled DNA fragments and unlabeled complementary strands of specific fragments. Early cytoplasmic RNA hybridized to the r-strand to EcoRI-C and BamHI-B and to the l-strand of BamHI-E. Hybridization to BamHI-C was also observed. The relative rates of accumulation of cytoplasmic RNA complementary to individual restriction fragments was measured at both early and late times. Early during infection, most of the viral RNA appearing in the cytoplasm was derived from the molecular ends of the genome. Later (24 to 26 h postinfection) the majority of the newly labeled cytoplasmic RNA was transcribed from DNA sequences mapping between 25 and 60 map units on the genome.
Properties of a persistent viral infection: possible lysogeny by an enveloped nonlytic mycoplasmavirus
Authors: Putzrath R M , Maniloff J
Published: January 2020

MVL2, an enveloped double-stranded DNA mycoplasmavirus, causes a nonlytic infection of Acholeplasma laidlawii leading to the establishment of a persistent infection. Persistently infected clones were found to be resistant to superinfection by homologous virus, but could be infected by heterologous virus. Cells in a persistently infected culture had the potential to produce virus and transmitted this potential as a stable heritable trait. Mitomycin C and UV light induced an increase in infectious centers in persistently infected cultures.
Virus-coded origin of a 32,000-dalton protein from avian retrovirus cores: structural relatedness of p32 and the beta polypeptide of the avian retrovirus DNA polymerase
Authors: Schiff R D , Grandgenett D P
Published: January 2020

A 32,000-dalton protein (p32) located in avian retrovirus cores was immunoprecipitated from [35S]methionine-labeled avian myeloblastosis virus (AMV) propagated in cultured chicken embryo fibroblast cells by an antiserum preparation (sarc III) derived from tumor-bearing hamsters injected with cloned and passaged cells from an avian sarcoma virus-induced primary hamster tumor. Since sarc III serum apparently contained antibodies only to virus-coded proteins and not to chicken cellular proteins, the immunoprecipitation of p32 from AMV by sarc III serum strongly suggested that p32 is virus coded. The origin of p32 was more definitively established by demonstrating the existence of a structural relationship between p32 and the AMV DNA polymerase. AMV p32 cross-reacted with the beta polypeptide of AMV alphabeta DNA polymerase in radioimmunoprecipitation and radioimmunoprecipitation inhibition assays, indicating that p32 and beta share common antigenic determinants. This relationship was clarified by sodium do-decyl sulfate-polyacrylamide gel electrophoretic analysis of the peptides generated by limited proteolysis of 125I-labeled AMV DNA polymerase polypeptides and of 125I-labeled AMV p32 by chymotrypsin or Staphylococcus aureus V-8 protease. The peptides which appeared during proteolytic digestion of p32 were a subset of those produced by digestion of the beta polypeptide; however, p32 had no discernible peptides in common with the alpha polypeptide. Further, all of the peptides produced by limited proteolysis of beta were present in the digests of either p32 or alpha. Our findings suggest that p32 is apparently derived by cleavage of the beta polypeptide of AMV DNA polymerase, presumably at a site near or identical to that at which alpha is generated from beta by proteolytic cleavage.
Transcription and translation of Newcastle disease virus mRNA's in vitro
Authors: Collins P L , Hightower L E , Ball L A
Published: January 2020

Transcription directed in vitro by Triton-activated Newcastle disease virus (NDV) was stimulated and prolonged by the presence of cytoplasmic extracts of animal cells. The RNA products closely resembled those of NDV transcription in vivo by several criteria: binding to oligodeoxythymidylic acid-cellulose, the mobility and relative abundance of each major band resolved by polyacrylamide gel electrophoresis, and the ability to direct the accurate cell-free synthesis of polypeptides corresponding to the NDV proteins HN, F0/F1, NP, and M. Synthesis of a novel polypeptide related to NP but of higher apparent molecular weight was also detected. These results indicated that cell-free transcription under these conditions was a close facsimile of NDV transcription in vivo. In addition, both in vitro and in vivo, NDV polypeptides were synthesized in nonequimolar amounts which reflected the order of the genes in the transcriptional map: NP, F0, M, (47K, HN), L. Strains AV and HP, virulent strains which have differences in biological activities, exhibited differences in the polypeptides synthesized in infected cells and in cell-free systems.
Conditions leading to the establishment of the N (a gene dependent) and A (a gene independent) transformed states after polyoma virus infection of rat fibroblasts
Authors: Rassoulzadegan M , Seif R , Cuzin F
Published: January 2020

Infection of normal rat fibroblasts (FR 3T3) with the early tsa mutant of polyoma virus may lead to either the A or the N phenotype, tsa-A transformants, originally derived by agar selection, are not temperature dependent for maintenance of the transformed phenotype, whereas tsa-N transormants revert at high temperature to normal growth control. A transformants did not result from an independent cellular mutation selected in agar medium, but rather from a transformation process distinct from that leading to the N state. It occurred in both liquid and agar media when the infected cells were maintained under growth-restricting conditions, such as absence of anchorage and contact inhibition at confluency. N transformation occurred in cells maintained in active growth after virus infection (sparse cultures on a solid substratum). Physiological conditions during a critical period after virus infection thus appear to be a crucial parameter of the transformation process.
Does simian virus 40 DNA integrate into cellular DNA during productive infection?
Authors: Rigby P W , Berg P
Published: January 2020

Late after infection of permissive monkey cells by simian virus 40 (SV40), large amounts of SV40 DNA (30,000 to 220,000 viral genome equivalents per cell) can be isolated with the high-molecular-weight fraction of cellular DNA. Hirai and Defendi (J. Virol.9:705-707, 1972) and Hölzel and Sokol (J. Mol. Biol. 84:423-444, 1974) suggested that this SV40 DNA is covalently integrated into the cellular DNA. However, our data indicate that the high-molecular-weight viral DNA is composed of tandem, "head-to-tail" repeats of SV40 DNA and that very little, if any, of this viral DNA is covalently joined to the cellular DNA. This was deduced from the following experimental findings. The size of the SV40 DNA associated with the high-molecular-weight cellular DNA fraction is greater than 45 kilobases, based on its electrophoretic mobility in agarose gels. In this form the SV40 DNA did not produce heteroduplex structures with a marker viral DNA (an SV40 genome with a characteristic deletion and duplication). After the high-molecular-weight DNA was digested with EcoRI or HpaII endonucleases, enzymes which cleave SV40 DNA once, more than 95% of the SV40 DNA migrated as unit-length linear molecules and, after hybridization with the marker viral DNA, the expected heteroduplex structures were easily detected. Digestion of the high-molecular-weight DNA fraction with restriction endonucleases that cleave cellular, but not SV40. DNA did not alter the electrophoretic mobility of the polymeric SV40 DNA, nor did it give rise to molecules that form heteroduplex structures with the marker viral DNA. Polymeric SV40 DNA molecules produced after coinfection by two physically distinguishable SV40 genomes contain only a single type of genome, suggesting that they arise by replication rather than by recombination. The polymeric form of SV40 DNA is highly infectious for CV-1P monolayers (6.5 X 10(4) PFU per microgram of SV40 DNA), yielding virtually exclusively normal, covalently closed circular, monomer-length DNA. Quite clearly these cells have an efficient mechanism for generating monomeric viral DNA from the SV40 DNA polymers.
Hexagonal glycoprotein arrays from Sindbis virus membranes
Authors: von Bonsdorff C H , Harrison S C
Published: January 2020

Freeze-etch electron microscopy of Sindbis virus and of glycoprotein arrays derived from Sindbis membranes by nonionic detergent treatment shows that the local geometry of glycoprotein-glycoprotein interaction does not depend on the presence of the nucleocapsid.
Transcription of bacteriophage M13 DNA: existence of promoters directly preceding genes III, VI, and I
Authors: Edens L , Konings R N , Schoenmakers J G
Published: January 2020

In vitro transcription and coupled transcription-translation studies have been performed with restriction fragments of bacteriophage M13 replicative-form DNA which contain either gene III, gene VI, or gene I. It could be demonstrated that DNA fragments which contain gene III were able to direct the synthesis of gene III protein. Fragments which encompassed genes VI and I gave rise to the synthesis of gene I protein only, whereas gene I-containing fragments were able to direct the synthesis of gene I protein. None of the fragments studied gave rise to a detectable level of gene VI protein, although an RNA transcript of gene VI could readily be obtained during in vitro transcription of the relevant gene VI-containing DNA fragments. From these results we have concluded that the promoters A0.44 and A0.49 are located in front of genes VI and I, respectively, and that gene III is also equipped with a promoter (X0.25). Introduction of a single cleavage within the gene III region does not abolish the expression of genes VI and I in vitro. Hence, the expression of these genes is not solely dependent on the initiation of RNA synthesis at the gene III promoter or on leakage of transcription through the central termination site (T0.25), but is also determined by the initiation frequency of RNA synthesis at their individual promoters.
Host range restriction of vaccinia virus in Chinese hamster ovary cells: relationship to shutoff of protein synthesis
Authors: Drillien R , Spehner D , Kirn A
Published: January 2020

Chinese hamster ovary cells were found to be nonpermissive for vaccinia virus. Although early virus-induced events occurred in these cells (RNA and polypeptide synthesis), subsequent events appeared to be prevented by a very rapid and nonselective shutoff of protein synthesis. Within less than 2 h after infection, both host and viral protein syntheses were arrested. At low multiplicities of infection, inhibition of RNA synthesis with cordycepin resulted in failure of the virus to block protein synthesis. Moreover, infection of the cells in the presence of cycloheximide prevented the immediate onset of shutoff after reversal of cycloheximide. Inactivation of virus particles by UV irradiation also impaired the capacity of the virus to inhibit protein synthesis. These results suggested that an early vaccinia virus-coded product was implicated in the shutoff of protein synthesis. Either the nonpermissive Chinese hamster ovary cells were more sensitive to this inhibition than permissive cells, or a regulatory control of the vaccinia shutoff function was defective.
Characterization of a variant of human adenovirus type 2 which multiples efficiently in simian cells
Authors: Klessig D F , Hassell J A
Published: January 2020

In a previous report (Klessig, J. Virol. 21:1243--1246, 1977), the isolation of a variant (H2hr400) of adenovirus serotype 2 (Ad2) that overcomes the block to multiplication of wild-type Ad2 in simian cells was described. H2hr400 replicates efficiently on both human and simian cells, resulting in virus yields that are comparable to those found when wild-type Ad2 infects permissive, human cells. An extensive comparison of the genome of H2hr400 with that of its parent by restriction endonuclease, electron microscopic, and hybridization analyses failed to detect any differences and excludes the possibility that simian virus 40 sequences, which in certain Ad2-simian virus 40 hybrid viruses (e.g., Ad2+ND1) allow adenovirus to multiply efficiently in simian cells, are present in H2hr400. In contrast to Ad2, H2hr400 can fully express its late genes in both simian and human cells. The mutation has been mapped by a modified marker rescue technique to the segment of the viral genome located between coordinates 59 and 80.
Effect of actinomycin D on the expression of herpes simplex virus-common surface antigen in cells transformed by herpes simplex virus type 2
Authors: Kimura S , Okazaki K , Yoshida N , Ohnishi Y
Published: January 2020

Using rabbit antiserum hyperimmune to herpes simplex virus (HSV) type 1, the expression of HSV-common surface antigen(s) was studied by indirect immunofluorescence tests in cells transformed by HSV type 2 and in derived tumor cells. The following results were obtained. (i) Antiserum to HSV type 1 reacted specifically with surface antigen present on the plasma membrane of both HSV type 2-infected and HSV type 2-transformed hamster cells. (ii) The expression of this antigen was enhanced in the absence of active protein synthesis in transformed cells, but not in tumor cells, after culture for 3 to 5 h at 37 degrees C. (iii) This enhancement of expression was maintained for 20 h in the presence of actinomycin D, but this prolonged expression required active protein synthesis. (iv) The enhancing effect observed in the presence of actinomycin D continued for some time after removal of the drug, for example, for 20 h after 5 h of treatment with 2 microgram/ml of actinomycin D per ml. Actinomycin D had no detectable effect on antigen expression in tumor cells. (v) The protease inhibitor antipain inhibited the actinomycin D-enhanced expression without causing significant cell damage but did not modify the transient enhanced expression of antigen when cells were seeded in the absence of actinomycin D. These results indicate that in transformed cells antigen expression can be enhanced in at least two ways.
Morphological and biochemical characterization of viral particles produced by the tsO45 mutant of vesicular stomatitis virus at restrictive temperature
Authors: Schnitzer T J , Dickson C , Weiss R A
Published: January 2020

The growth at restrictive temperature of tsO45, a group V (glycoprotein) conditional lethal mutant of vesicular stomatitis virus (VSV), was demonstrated to result in the production of large numbers of noninfectious viral particles. The infectivity of these tsO45 particles could be enhanced by procedures known to promote membrane fusion. Morphologically and biochemically these particles differed from wild-type VSV by their lack of viral glycoprotein. The other structural proteins of VSV were present and indistinguishable by size and relative proportion from those of virus grown at the permissive temperature. Examination of glycoprotein maturation at the restrictive temperature (39.5 degrees C) in tsO45-infected cells demonstrated the synthesis of normal viral glycoprotein but failed to demonstrate the presence of this glycoprotein in either the cell membrane or the envelope of free virions. The further absence of soluble viral glycoprotein from the supernatants of such cells strongly suggests that viral glycoprotein may not be necessary for the successful budding of VSV.
Isolation of a nucleocapsid polypeptide of herpes simplex virus types 1 and 2 possessing immunologically type-specific and cross-reactive determinants
Authors: Heilman C J , Zweig M , Stephenson J R , Hampar B
Published: January 2020

A polypeptide (p40) of approximately 40,000 molecular weight was isolated from herpes simplex virus type 1 and 2 nucleocapsids by gel filtration and ion exchange chromatography. This protein appears to be the same as protein 22a described previously (Gibson and Roizman, J. Virol. 10:1044--1052, 1972). Competition immunoassays were developed by using purified p40 and antisera prepared in guinea pigs. The assays indicated that the p40's from herpes simplex virus types 1 and 2 possess both type-specific and cross-reactive antigenic determinants. Antibodies to the p40 cross-reactive determinant reacted with antigens in simian herpes virus SA8-infected cells, but not with antigens induced by pseudorabies virus. Preliminary results indicated that a radioimmunoprecipitation test can be used to detect type-specific herpes simplex virus p40 antibodies in human sera.
Recombination of bacteriophage phi X174 by the red function of bacteriophage lambda
Authors: Munekiyo R , Sekiguchi M
Published: January 2020

Recombination of bacteriophage phi X174 was effectively promoted when the Red function of lambda was supplied by either co-infection with lambda or induction of lambda lysogens. Mutations in red alpha and red beta genes of lambda abolished recombination nearly completely, whereas a mutation in gam gene reduced it only slightly. The Red-promoted recombination of phi X174 occurred in recA, recB, and polA mutants as well as in wild-type strains of Escherichia coli. It was further stimulated when phi X174 mutants were irradiated with UV light before infection.
Evidence that the RNA Polymerase Usually Does Not Make a Complete Transcript of the Late Strand of Simian Virus 40 DNA
Authors: Fried Allan H.
Published: January 2020

An important model for the transcription of the late (L) strand of simian virus 40 DNA is that, late after infection of permissive monkey cells, the RNA polymerase makes a complete transcript of the L DNA strand before terminating transcription. The purpose of the current work was to test a prediction of this model, namely, that the rate of synthesis of all RNA sequences from the L DNA strand should be equal. About one-half of the L DNA strand is transcribed into late mRNA sequences and the other half into late dRNA sequences, which do not leave the nucleus. Using glucosamine to reduce the size of the intracellular UTP pool before and after a pulse-label with radioactive uridine, a pulse-chase experiment was performed to determine the half-lives of these sequences. The half-life of the late dRNA sequences was determined to be 4 min. The late mRNA sequences were degraded more slowly, on the average, than the late dRNA sequences. In a parallel experiment with similarly treated cells, it was shown that after a 2-min label with radioactive uridine there was only 0.2 times as much radioactivity in the late dRNA sequences as in the late mRNA sequences in the total cellular RNA population. The results could be combined to calculate that the rate of synthesis of the late dRNA sequences was at most 0.3 times that of the late mRNA sequences. Consequently they provide strong evidence that when the RNA polymerase transcribes the late mRNA sequences, it usually terminates transcription before all the late dRNA sequences are transcribed.
Construction and characterization of the hybrid bacteriophage lambda Charon vectors for DNA cloning
Authors: Williams B G , Blattner F R
Published: January 2020

Twenty hybrid lambda phages especially designed for molecular cloning have been constructed and named Charon phages. These phages differ in the ranges of sizes of DNA fragments that may be inserted, by the selections and screens which may be used to isolate and detect the incorporation of cloned fragments, by the way transcription of the cloned fragment may be controlled, by the different restriction enzymes that can be used for cloning, by the phage immunities that may be employed for controlling replication and transcription, and by the biological safety features that they contain. The crosses used to produce the vectors are described, and their genealogy is discussed. The structure of each vector has been verified by genetic tests, by DNA length determinations, by electron micrographic analysis of DNA heteroduplexes, and by gel electrophoresis of restriction enzyme digests. In the course of these constructions, a new EcoRI site was found in a derivative of lambda Aam32Bam1 which maps very near the left cohesive end of lambda.
Interruption-deficient mutants of bacteriophage T5. II. Properties of a mutant lacking a specific interruption
Authors: Rogers S G , Hamlett N V , Rhoades M
Published: January 2020

An examination was made of the properties of T5HA4, a mutant of bacteriophage T5 that lacks the single-chain interruption that occurs at 7.9% from the left end of the genome. The DNAs of T5HA4 and the wild type were compared by electrophoresis in agarose gels of both single-stranded fragments produced by denaturation and duplex fragments generated by sequential treatment with exonuclease III and SI nuclease. These studies demonstrated that T5HA4 also lacks an interruption that occurs at 99.6% in wild-type DNA. The interruptions at 7.9 and 99.6% therefore occur within the 8.3% of T5 DNA that is terminally repetitious. Evidence on the location of other interruptions within the terminal repetition was also obtained. Analysis of T5HA4 with a restriction endonuclease indicated that the interruption deficiency is not due to a deletion or addition mutation. The injection of T5HA4 DNA into a host bacterium was found to occur, as with the wild type, in a two-step manner. The interruption at 7.9% is therefore not required for stopping DNA transfer after the initial 8% segment has been injected.
Formation of Rous associated virus-60: origin of the polymerase gene
Authors: Sawyer R C , Rettenmier C W , Hanafusa H
Published: January 2020

The DNA of normal chicken embryos contains sequences related to the avian leukosis-sarcoma viruses. RNA-dependent DNA polymerase of these viruses is encoded by a genetic element known as the pol gene. The nature of the endogenous virus pol gene in chicken cells was investigated by testing its ability to participate in genetic recombination. Rous-associated virus-60-type recombinant viruses isolated after infection of chicken cells with strains tsLA337PR-B or tsNY21SR-A, both of which produce a temperature-sensitive DNA polymerase, also possessed the temperature-sensitive lesion. These results are consistent with the hypothesis that the endogenous viral information used for the generation of Rous-associated virus-60 is deficient in at least part of the pol gene and that the defect includes that portion represented by the lesions in NY21 and LA337. The frequency of polymerase-negative BH-Rous sarcoma virus alpha formation was not affected by the levels of endogenous viral expression, which suggests that the alpha defect is not derived from the endogenous pol gene.
Purification and characterization of an early glycoprotein from adenovirus type 2-infected cells
Authors: Persson H , Signäs C , Philipson L
Published: January 2020

An adenovirus type 2 early glycoprotein with an apparent molecular weight of 19,000 (E19K) in sodium dodecyl sulfate-polyacrylamide gels has been extensively purified. Purification involved detergent solubilization of membrane fractions from infected cells, followed by affinity chromatography on a lectin column and DEAE-Sephadex chromatography. The purified material contained three polypeptides (E40K, E19K, E17.5K), with approximately 90% of the material in the E19K moiety. All three polypeptides yielded identical tryptic peptide maps. The E19K polypeptide contained glucosamine as revealed by [3H]glucosamine labeling of infected cells and amino acid analysis of the purified protein. Immunoprecipitation with a monospecific antiserum showed that the E19K polypeptide started to be synthesized at 2 h, with a maximal rate at 4 h after infection. It was also synthesized at a low rate late in the infectious cycle (12 to 24 h postinfection). Immunoprecipitation from three adenovirus type 2-transformed hamster embryo cell lines and two adenovirus type 2-transformed rat cell lines revealed that one of the hamster cell lines (ad2HE4) and one of the rat cell lines (A2T2C4) expressed this protein.
Transfection of Lysostaphin-treated Cells of
Staphylococcus aureus
Authors: Riggs H. G. , Rosenblum E. D.
Published: January 2020

After treatment with 1 unit of lysostaphin per ml for 3 min, two strains of
Staphylococcus aureus
, 233 and PS 44A HJD, were transfected with phenol-extracted deoxyribonucleic acid (DNA) from the staphylococcal bacteriophages, 53 and 44A HJD, respectively. The number of transfected cells was low in both systems, approximately two in 10
7
enzyme-treated cells. There was a saturation effect at high concentrations of DNA; optimal results were obtained at concentrations between 10 to 25 μg/ml. Growth curves and fluctuation tests indicated that cells of strain 44A HJD infected with phage, then converted to protoplasts by a 10-min treatment with lysostaphin, produce only one phage particle and lose their ability to lyse spontaneously in hypertonic media.
Reversion in Polyoma-transformed Cells: Retransformation, Induced Antigens and Tumorigenicity
Authors: Marin G. , Macpherson I.
Published: January 2020

We studied the properties of two morphologically reverted cell clones isolated as chromosomal segregants from a “hybrid” clone of BHK 21/13 hamster fibroblasts, transformed with polyoma virus. Both clones were less tumorigenic than control transformed cells. They contained no detectable polyoma-specific complement-fixing antigen. Induced transplantation antigen also appeared to be lost or reduced. Both clones could be retransformed with polyoma virus, suggesting that their reversion is due to the loss of viral genes from the transformed cell.
Replication of Simian Foamy Virus in Monkey Kidney Cells
Authors: Clarke J. K. , Gay F. W. , Attridge J. J.
Published: January 2020

The structure of foamy virus, its mode of maturation, and the origin of vacuoles in monkey kidney cells are described.
Kinetics of Incorporation of Structural Proteins into Sindbis Virions
Authors: Scheele Christina M. , Pfefferkorn E. R.
Published: January 2020

The morphogenesis of Sindbis virus was studied by determining the kinetics with which newly synthesized nucleocapsid and envelope proteins appeared in virions released into the extracellular medium. Assembly of the nucleocapsid was more rapid than modification of the cellular membrane by the addition of the viral envelope protein. However, both viral structural proteins were efficiently incorporated into virions; a 0.5-hr pulse-labeling period resulted in the release of maximally labeled virus during the next hour. When protein synthesis was inhibited, release of virus soon declined even though large amounts of both viral structural proteins were present within the cell and ribonucleic acid replication was unaffected.
In Vitro Synthesis of Poliovirus Ribonucleic Acid: Role of the Replicative Intermediate
Authors: Girard Marc
Published: January 2020

Poliovirus ribonucleic acid (RNA) polymerase crude extracts could be stored frozen in liquid nitrogen without loss of activity or specificity. The major in vitro product of these extracts was viral single-stranded RNA. However, after short periods of incubation with radioactive nucleoside triphosphates, most of the incorporated label was found in replicative intermediate. When excess unlabeled nucleoside triphosphate was added, the label was displaced from the replicative intermediate and accumulated as viral RNA. It is concluded from this experiment that the replicative intermediate is the precursor to viral RNA. In addition, some of the label was chased into double-stranded RNA. The implications of this finding are discussed.
Micromorphological Aspects of the Development of Rubella Virus in BHK-21 Cells
Authors: Edwards Mercedes R. , Cohen Sophia M. , Bruno Minerva , Deibel Rudolf
Published: January 2020

Sequential effects of rubella virus infection in BHK-21 cells were studied by electron microscopy of thin sections of control and infected cells, 2 to 7 days after infection. Vacuolization of cytoplasm in Golgi areas apparently preceded budding of virions from vacuole membranes and involvement of the endoplasmic reticulum. Newly formed endoplasmic reticulum cisternae encircled and segregated virionforming vacuoles together with other cellular elements. Large vacuolar complexes with numerous virus particles developed, and virus release from these areas occurred with disruption at the cell periphery. The viral particles, with a mean diameter of about 56 nm, consisted of an electron-dense core surrounded by a less dense capsid, enveloped by a typical unit membrane derived from the vacuole membrane.
Phospholipid Metabolism in T4 Bacteriophage-infected
Escherichia coli
K-12 (λ)
Authors: Peterson Robert H. F. , Buller Clarence S.
Published: January 2020

Infection of
Escherichia coli
K-12 (λ) by bacteriophage results in an altered labeling pattern of phospholipids in the host cell. Although the overall incorporation of
32
P
i
into phospholipids is decreased by infection, the relative amounts of phosphatidylglycerol and cardiolipin are increased. Phospholipid changes occurring at later stages in the lytic cycle of infected bacteria are more prominent than those at earlier time intervals. The uptake of
32
P
i
into phospholipids of cells infected with T4B
s
and endolysin-negative mutants was similar to that observed with the wild-type phage, suggesting that the development of resistance to lysis from without and the repair of mucopeptides are not responsible for the phospholipid changes. The metabolism of phospholipids in uninfected cells treated with cyanide was similar to that of infected cells, indicating that part of the phage-induced alterations may be a consequence of impaired respiration.
Inheritance of Susceptibility to Friend Mouse Leukemia Virus
Authors: Odaka Takeshi
Published: January 2020

Based on the previous observation that a single major autosomal gene controls susceptibility to Friend leukemia virus in mice, an attempt was made to place the gene for susceptibility,
Fv
s
, from susceptible DDD mice into the genetic complement of resistant C57BL/6 mice. The backcross system was adopted for this purpose, the heterozygotes being selected by progeny test at each generation. During successive backcrosses, the effect of gene
Fv
s
was not diluted out, and progeny were almost always obtained as expected from the single-gene hypothesis, with respect to both genotype and phenotype. With the eighth backcross generation, brother-sister mating was done between the heterozygotes, and it produced mice homozygous for gene
Fv
s
. These susceptible homozygotes and their progeny produced by incross could be assumed congenic with C57BL/6 mice except for susceptibility to Friend leukemia virus. The results indicate that the appearance of early splenomegaly in Friend virus-infected mice is under the control of a single major autosomal gene.
Plaques of Hemagglutination Inhibition by Individual Spleen Cells from Rabbits Immunized with Influenza Viruses
Authors: Petersen B. H. , Brahmi Z. , Ingraham J. S. , Levine A. S.
Published: January 2020

Spleen cells from rabbits immunized with influenza virus cause inhibition of agglutination or hemolysis or both in a plaque assay test against virus-treated avian RBC.
Control of protein synthesis in Escherichia coli: control of bacteriophage Q beta coat protein synthesis after energy source shift-down
Authors: Leschine S B , Jacobson L A
Published: January 2020

Escherichia coli Q13 was infected with bacteriophage Q beta and subjected to energy source shift-down (from glucose-minimal to succinate-minimal medium) 20 min after infection. Production of progeny phage was about fourfold slower in down-shifted cultures than in the cultures in glucose medium. Shift-down did not affect the rate of phage RNA replication, as measured by the rate of incorporation of [14C]uracil in the presence of rifampin, with appropriate correction for the reduced entry of exogenous uracil into the UTP pool. Phage coat protein synthesis was three- to sixfold slower in down-shifted cells than in exponentially growing cells, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The polypeptide chain propagation rate in infected cells was unaffected by the down-shift. Thus, the reduced production of progeny phage in down-shifted cells appears to result from control of phage protein synthesis at the level of initiation of translation. The reduction in the rate of Q beta coat protein synthesis is comparable to the previously described reduction in the rate of synthesis of total E. coli protein and of beta-galactosidase, implying that the mechanism which inhibits translation in down-shifted cells is neither messenger specific nor specific for 5' proximal cistrons. The intracellular ATP pool size was nearly constant after shift-down; general energy depletion is thus not a predominant factor. The GTP pool, by contrast, declined by about 40%. Also, ppGpp did not accumulate in down-shifted, infected cells in the presence of rifampin, indicating that ppGpp is not the primary effector of this translational inhibition.
Identification of the primate papovavirus HD as the stump-tailed macaque virus
Authors: Howley P M , Newell N , Shah K V , Law M F , Gruss P , Sauer G , Kelly T J
Published: January 2020

The recently isolated primate papovavirus HD is shown to be indistinguishable from the stump-tailed macaque virus by immunofluorescent reactivity, by restriction endonuclease analysis, and by nucleic acid hybridization assay.
Protein synthesized early after infection is linked to the termini of adenovirus type 2 DNA synthesized in vivo and in vitro
Authors: Yamashita T , Arens M , Green M
Published: January 2020

The human adenovirus DNA genome contains a protein (CBP, or covalently bound protein) linked to each 5' terminus. To assess whether CBP is synthesized early, infected cells were incubated with hydroxyurea from 1 to 18 h postinfection, the hydroxyurea was removed, cycloheximide was added, and viral DNA was labeled with [3H]thymidine from 18 to 23 h postinfection. Removal of hydroxyurea at 18 h postinfection permits the synthesis of viral DNA, whereas cycloheximide maintains the block in late viral protein synthesis. Three lines of evidence are presented to show that viral 3H-labeled DNA prepared by this procedure was linked to CBP: (I) the DNA sedimented more rapidly than protein-free DNA (i.e., protinase treated) in neutral sucrose gradients containing guanidine hydrochloride; (ii) the DNA banded at a lower density than protein-free DNA in CsCl gradients containing guanidine hydrochloride; and (iii) neither the 3H-labeled DNA nor the end fragments produced by EcoRI digestion entered a 1.4% agarose gel during electrophoresis. These experiments are strong evidence that CBP is not a product of a late viral gene and is therefore the product of either an early viral gene or a cell gene. Experiments were performed to test whether CBP is attached to viral DNA synthesized in vitro by a soluble complex that synthesizes exclusively viral DNA as completed viral genomes in vitro. In vitro-labeled DNA was analyzed by velocity sedimentation, equilibrium sedimentation, and agarose gel electrophoresis as described above. Our results indicate that the majority of in vitro-synthesized DNA molecules were attached to CBP. These results, which indicate that CBP is synthesized early after infection and is attached to viral DNA labeled in vitro by a soluble replication complex, are consistent with the idea that CBP may play a role in viral DNA replication.
Comparison of the genomes of simian, bovine, and human rotaviruses by gel electrophoresis and detection of genomic variation among bovine isolates
Authors: Rodger S M , Holmes I H
Published: January 2020

By co-electrophoresis in polyacrylamide gels, the segmented double-standed RNA genome of the simian rotavirus, SA 11, was compared with those of human and bovine rotaviruses. A comparison between SA 11 virus and the Northern Ireland cell culture adapted bovine virus showed that the electrophoretic mobilities of each of the 11 corresponding segments differed. In other comparisons, four to seven segment variations were more common. When the genomes of various bovine rotaviruses were compared, eight different electropherotypes were detected. Four of these electropherotypes were obtained from one property during a single outbreak of disease. In view of such genetic diversity, a scheme for the systematic designation of different rotavirus samples is proposed. The significance of the variations in relation to the molecular epidemiology of bovine rotavirus infections is discussed.
Physical map of bacteriophage BF23 DNA: restriction enzyme analysis
Authors: Lange-Gustafson B , Rhoades M
Published: January 2020

Cleavage maps of bacteriophage BF23 DNA have been constructed for the restriction endonucleases SalI (3 fragments), BamHI (5 fragments), EcoRI, (8 fragments), BalI (13 fragments), and HpaI (49 fragments, 32 of which have been ordered). The maps were determined by (i) analysis of deletion mutants, (ii) digestion with two endonucleases, (iii) digestion of isolated fragments with a second enzyme, (iv) analysis of partial digests, and (v) digestion after treatment with lambda exonuclease.
Cleavage map of bacteriophage T4 cytosine-containing DNA by sequence-specific endonucleases SalI and KpnI
Authors: Carlson K , Nicolaisen B
Published: January 2020

Cytosine-containing T4 DNA from endoII- endoIV- dCTPase- alc2 phage grown in a sup+ rB- mB- host is cleaved by endo R.EcoRI and endo R.HindIII to greater than 40 fragments and by endo R.SalI and endo R.KpnI to 8 and 6 fragments, respectively. The latter two fragment sets have been correlated to each other to produce a cleavage map of the genome. The sum of the molecular weights of the fragments calculated from electrophoretic mobility in agarose gels yields a genome molecular weight for cytosine-containing T4 DNA of 105 x 10(6).
Intracellular forms of simian virus 40 nucleoprotein complexes. II. Biochemical and electron microscopic analysis of simian virus 40 virion assembly
Authors: Coca-Prados M , Hsu M T
Published: January 2020

The simian virus 40 virion assembly process was studied with pulse-labeling kinetics of virion proteins, CsCl gradient analysis, electron microscopy, and low-salt gel electrophoresis. The results obtained are consistent with the model of gradual addition and organization of capsid proteins around simian virus 40 chromatin. Empty virions, as observed in the CsCl gradient by previous workers, were found to be the dissociation product of immature virus. Histone H1 was found in simian virus 40 chromatin and virion assembly intermediates but not in the mature virion banding at 1.34 g/ml in the CsCl gradient.
Cell killing by spleen necrosis virus is correlated with a transient accumulation of spleen necrosis virus DNA
Authors: Keshet E , Temin H M
Published: January 2020

Spleen necrosis virus productively infects avian and rat cells. The average number of molecules of unintegrated and integrated viral DNA in cells at different times after infection was determined by hybridization and transfection assays. Shortly after infection, there was a transient accumulation of an average of about 150 to 200 molecules of unintegrated linear spleen necrosis virus DNA per chicken, turkey, or pheasant cell. No such accumulation was seen in infected rat cells. Soon after infection there was in chicken cells, but not inturkey, pheasant, or rat cells, also a transient integration of an average of 35 copies of viral DNA per cell. By 10 days after infection, the majority of this integrated viral DNA was lost from the population of infected chicken cells. At the same time, the majority of the unintegrated viral DNA was also lost from infected chicken, turkey, and pheasant cells. The transient cytopathic effect seen in these infected cells also occurred at this time. Late after infection about five copies of apparently nondefective spleen necrosis proviruses were stably integrated at multiple sites in chicken, turkey, pheasant, and rat DNA. These results demonstrate a correlation between the transient accumulation of large numbers of spleen necrosis virus DNA molecules and the transient occurrence of cytopathic effects.
Suppression of multiplication of avian sarcoma virus by rapid spread of transformation-defective virus of the same subgroup
Authors: Estis L F , Temin H M
Published: January 2020

We have tested the hypothesis that some transformation-defective (td) viruses grow faster than the avian sarcoma viruses (ASV) from which they are derived, resulting in establishment of interference by the td virus and suppression of the ASV multiplication. Using an ASV of subgroup A (ASV-A) that does not contain td virus and an independently isolated tdASV-A, we performed separate and mixed infections to test this hypothesis. At multiplicities of 1 or less, tdASV alone grew to higher titers and more rapidly than ASV alone. In mixed infections at low multiplicities that allowed spread of progeny virus, when as little as 10% of the virus inoculum was td virus, there was an excess of td virus by 2 days after infection and a decrease in the titer of ASV relative to a control infection with no td virus. In mixed infections at high multiplicities which minimized spread of progeny virus, there was no excess of td virus and the titer of ASV was not decreased relative to the control infection with no td virus. These data support the hypothesis that we proposed and indicate that deletions in the ASV src gene may not be a high-frequency event. We also present data concerning the amounts of unintegrated viral DNA found after the separare and mixed infections. There was no simple correlation between the amounts of unintegrated viral DNA early after infection and the titers of virus produced, indicating perhaps that virus production was determined by integrated viral DNA.
Simian virus 40-transformed cells express new species of proteins precipitable by anti-simian virus 40 tumor serum
Authors: Kress M , May E , Cassingena R , May P
Published: January 2020

In addition to the virus-coded large-T and small-t antigens, two new classes of proteins were immunoprecipitated by anti-simian virus 40 (SV40) tumor serum from extracts of various SV40-transformed cell lines. These were as follows: (i) proteins (termed "super-T proteins") with an Mr higher than that of large-T antigen (86,000), which were found in many SV40-transformed cell lines derived from mouse and rat cells (super-T proteins and large-T antigen appeared to have closely related structures as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides); (ii) proteins (termed "55K proteins") with an Mr ranging from 50,000 to 60,000, which were present in all SV40-transformed cell lines examined so far, including those obtained by chromosome-mediated gene transfer. The 55K proteins were not structurally related to large-T antigens, as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides. Our data are compatible with the assumption that the 55K proteins are largely or totally cell coded.
Cell surface location of simian virus 40-specific proteins on HeLa cells infected with adenovirus type 2-simian virus 40 hybrid viruses Ad2+ND1 and Ad2+ND2
Authors: Deppert W , Pates R
Published: January 2020

HeLa cells infected with the nondefective adenovirus type 2-simian virus 40 hybrid viruses Ad2+ND1 or Ad2+ND2 were analyzed for cell surface location of the SV40-specific hybrid virus proteins by indirect immunofluorescence microscopy. Two different batches of sera from SV40 tumor-bearing hamsters, serum from SV40 tumor-bearing mice, or two different antisera prepared against purified sodium dodecyl sulfate-denatured SV40 T-antigen, respectively, were used. All sera were shown to exhibit comparable T- and U-antibody titers and to specifically immunoprecipitate the SV40-specific proteins from cell extracts of Ad2+ND2-infected cells. Whereas analysis of living, hybrid virus-infected HeLa cells did not yield conclusive results, analysis of Formalin-fixed cells resulted in positive cell surface fluorescence with both Ad2+ND1- and Ad2+ND2-infected HeLa cells when antisera prepared against sodium dodecyl sulfate-denatured SV40 T-antigen were used as first antibody. In contrast, sera from SV40 tumor-bearing animals were not or only very weakly able to stain the surfaces of these cells. The fact that the tumor sera had comparable or even higher T- and U-antibody titers than the antisera against sodium dodecyl sulfate-denatured T-antigen but were not able to recognize SV40-specific proteins on the cell surface suggests that SV40 tumor-specific transplantation antigen may be an antigenic entity different from T- or U-antigen.
Mice with Spontaneous Mammary Tumors Develop Type-Specific Neutralizing and Cytotoxic Antibodies Against the Mouse Mammary Tumor Virus Envelope Protein gp52
Authors: Schochetman Gerald , Arthur Larry O. , Long Cedric W. , Massey Richard J.
Published: January 2020

Sera from C3H mammary tumor-bearing mice contain cytotoxic antibodies for mouse mammary tumor virus (MMTV)-producing cells, based on
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Cr release in a complement-dependent serum cytotoxicity assay. The cytotoxic antibodies could be absorbed by purified C3H MMTV gp52 and C3H MMTV-infected cat cells (C3H [MMTV] CrFK) containing cell surface MMTV gp52. However, purified MMTV p27 and uninfected CrFK cat cells were negative. Absorption of the sera with GR (MMTV) CrFK cells also removed all of the cytotoxicity, whereas absorption with RIII (MMTV) CrFK cells was negative, even though all three infected cat cells contained equivalent amounts of gp52. The same C3H cytotoxic sera also neutralized the focus-forming capacity of a C3H MMTV pseudotype of Kirsten sarcoma virus containing MMTV gp52. In contrast, sera from mammary tumor-bearing GR and RIII mice did not neutralize the pseudotype. Furthermore, neutralization could be achieved only by anti-gp52 but not by anti-gp36, -p27, -p14, or -p10 C3H MMTV sera. The gp52's of C3H, GR, and RIII MMTV could also be distinguished by using a type-specific competition radioimmunoassay employing
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I-gp52 of C3H MMTV and a hyperimmune rabbit anti-C3H MMTV serum. To demonstrate these differences directly, we studied the primary structure of gp52 on the surface of the C3H, GR, and RIII (MMTV) CrFK cells. Two-dimensional tryptic peptide maps of the cell surface lactoper-oxidase-catalyzed iodinated gp52's revealed a greater number of peptides common to the gp52's of C3H and GR MMTVs than to RIII MMTV gp52. These results demonstrate that gp52 is a major target antigen for both cytotoxic and neutralizing antibodies, that the cell surface and virion-associated gp52's of C3H, GR, and RIII MMTV contain both group- and type-specific determinants, and that C3H and GR MMTV gp52's are antigenically more related to each other than to RIII MMTV gp52. Furthermore, C3H mammary tumor-bearing mice develop type-specific antibodies capable of recognizing unique gp52 determinants and, therefore, are able to distinguish the gp52 of C3H MMTV from the gp52's of GR and RIII MMTV.