bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Bacteriophage S13
su
N15 Single-Strand and Replicative-Form Deoxyribonucleic Acid
Authors: Spencer J. H. , ˘Cerný R. , ˘Cerná E. , Delaney A. D.
Published: January 2020

The deoxyribonucleic acid (DNA) of bacteriophage S13 was shown to be single-stranded by the criteria of reactivity with formaldehyde, dependence of optical density on ionic strength, broad temperature-absorbance profile, and lack of molar equivalence of the purine and pyrimidine bases. The DNA has a molecular weight of 1.8 × 10
6
daltons, an
S
°
20
of 24.6 in SSC (0.15
m
NaCl plus 0.015
m
sodium citrate), and a buoyant density of 1.726 g/cc in CsCl. Electron microscopy showed the molecule to be circular. S13 replicative-form DNA was shown to be a double-stranded, circular molecule with a molecular weight of 3.5 × 10
6
daltons, an
S
[ill]
of 20.7 in SSC, and a buoyant density in CsCl of 1.710 g/cc. The finding that S13 DNA is slightly more pyrimidine-rich than φX174 DNA but is indistinguishable by all other parameters supports the close genetic relationship between the two bacteriophages.
Bacteriophage SP82G Inhibition of an Intracellular Deoxyribonucleic Acid Inactivation Process in
Bacillus subtilis
Authors: McAllister William T. , Green D. MacDonald
Published: January 2020

The stability of SP82G bacteriophage deoxyribonucleic acid (DNA) after its uptake by competent
Bacillus subtilis
was examined by determining the ability of superinfecting phage particles to rescue genetic markers carried by the infective DNA. These experiments show that a DNA inactivation process within the cell is inhibited after infection of the cell by intact phage particles. The inhibition is maximally expressed 6 min after phage infection and is completely prevented by the addition of chloramphenicol at the time of infection. The protective effect of this function extends even to infective DNA which was present in the cell before the addition of intact phage. Continued protein synthesis does not appear to be a requirement for the maintenance of the inhibition. In an analogous situation, if infectious centers resulting from singly infecting phage particles are exposed to chloramphenicol shortly after the time of infection, an exponential decrease in the survival of infectious centers with time held in chloramphenicol is observed. If the addition of chloramphenicol is delayed until 6 min after infection, the infectious centers are resistant to chloramphenicol. The sensitivity of infectious centers treated with chloramphenicol at early times after infection is strongly dependent upon the multiplicity of infection and is consistent with a model of multiplicity reactivation. These results indicate that injected DNA is also susceptible to the intracellular inactivation process and suggest that the inhibition of this system is necessary for the successful establishment of an infectious center.
Properties of Somatic Cell Hybrids Between Mouse Cells and Simian Virus 40-Transformed Rat Cells
Authors: van der Noordaa J. , van Haagen Anne , Walboomers J. M. M. , van Someren H.
Published: January 2020

Hybrids between mouse cells and simian virus 40 (SV40)-transformed rat cells were made, and their properties and chromosome constitution were investigated over many generations. Their hybrid nature was confirmed by enzyme studies. During a period of 1 year a loss of 10 to 20% of the total number of chromosomes was observed. The SV40 tumor antigen was present and remained present in the hybrids. The parental and hybrid cells were studied for agglutination with concanavalin A, for growth in soft agar, and for serum requirement. These growth and surface characteristics of the transformed cells appeared in the hybrids.
Adenovirus-Associated Virus Multiplication VIII. Analysis of In Vivo Transcription Induced by Complete or Partial Helper Viruses
Authors: Carter Barrie J. , Rose James A.
Published: January 2020

We have analyzed ribonucleic acid (RNA) synthesized in KB cells co-infected with adenovirus-associated virus (AAV) type 2 and either adenovirus type 2 (Ad2) or herpes simplex virus type 1 (HSV-1). With either type of helper virus, synthesis of AAV RNA was readily detected by deoxyribonucleic acid (DNA)-RNA hybridization. As is the case for AAV RNA synthesized with helper Ad2, the AAV RNA synthesized with HSV-1 as helper annealed only to the thymidine-rich (minus) AAV DNA strand. In addition, AAV RNA synthesized with either type of helper (i) contained similar nucleotide sequences as determined by hybridization inhibition tests and (ii) had a mean molecular weight of approximately 7.5 × 10
5
based on sedimentation in dimethylsulfoxide-sucrose gradients. These experiments suggest that the restricted helper function of HSV-1 is not due to abnormal transcription of the AAV genome. Since the mean molecular weight of AAV RNA is equivalent to 40 to 50% of the AAV genome, as few as two or three AAV RNA species may be transcribed in vivo. In contrast to adenovirus RNA, cleavage of AAV RNA after transcription was not observed.
Induction of Deoxyribonucleic Acid Synthesis and the Oncogenicity of Marek's Disease Virus
Authors: Lee Lucy F.
Published: January 2020

Leukocytes recovered from birds inoculated with an oncogenic strain of Marek's disease virus synthesized deoxyribonucleic acid in vitro at a rate 7.9 times that of leukocytes from normal birds or birds inoculated with the nononcogenic herpesvirus of turkeys. A close relationship was observed between the level of in vitro deoxyribonucleic acid synthesis and in vivo tumor formation.
Sensitivity of Ribonucleic Acid and Deoxyribonucleic Acid Viruses to Different Species of Interferon in Cell Cultures
Authors: Youngner Julius S. , Thacore Harshad R. , Kelly Marion E.
Published: January 2020

Although two deoxyribonucleic acid (DNA) viruses, pseudorabies (PsRV) and vaccinia, are as susceptible as a ribonucleic acid (RNA) virus, vesicular stomatitis (VSV), to interferon when tested in chicken or mouse cells, they are refractory to inhibition in interferon-treated primary rabbit kidney cells and in a continuous line (RK-13) of rabbit kidney cells. Superinfection with VSV of RK-13 cells first infected with PsRV completely blocks the replication of PsRV with no effect on VSV yield. When the same experiment is carried out in RK-13 cells pretreated with 1,000 units of interferon, VSV replication is inhibited, which permits PsRV to replicate normally. These findings demonstrate that
in the same cell
one virus (PsRV) can be refractory to interferon and a second virus (VSV) can be susceptible. These experiments show that rabbit kidney cell cultures are deficient in the synthesis of resistance factors active against the DNA viruses tested and raise the possibility that separate resistance factors may exist for RNA and DNA viruses. In the case of sequential infection of interferon-treated RK-13 cells with vaccinia and VSV, it was found that not only was vaccinia replication refractory to inhibition by interferon, but also that prior infection with vaccinia was able to partially reverse the effect of the inhibitor on the replication of the VSV used for superinfection. On the basis of these and other data it is postulated that a vaccinia virion component or a replication product of vaccinia virus, or both, enables VSV to escape the inhibiting action of interferoninduced resistance factors.
Plasmid-Controlled Variation in the Content of Methylated Bases in Bacteriophage Lambda Deoxyribonucleic Acid
Authors: Hattman Stanley
Published: January 2020

The
N
6
-methyladenine (MeAde) and 5-methylcytosine (MeC) contents in deoxyribonucleic acid (DNA) of bacteriophage lambda has been analyzed as a function of host specificity. The following facts have emerged: (i) lambda grown on strains harboring the P1 prophage contain ca. 70 more MeAde residues/DNA molecule than lambda grown either in the P1-sensitive parent, or in a P1 immune-defective lysogen which does not confer P1 modification; (ii) lambda grown on strains harboring the N-3 drug-resistance factor contain ca. 60 more MeC residues/DNA molecule than lambda grown on the parental strain lacking the factor; (iii) lambda grown in
Escherichia coli
B strains is devoid of MeC, whereas lambda grown in a B (N-3) host contains a high level of MeC; (iv) the MeAde content in lambda DNA is not affected by the N-3 factor. These results suggest that P1 controls an adenine-specific DNA methylase, and that the N-3 plasmid controls a cytosine-specific DNA methylase. The N-3 factor has been observed previously to direct cytosine-specific methylation of phage P22 DNA and
E. coli
B DNA in vivo; in vitro studies presented here demonstrate this activity.
Filamentous Bacterial Viruses VI. Role of fd Gene 2 in Deoxyribonucleic Acid Replication
Authors: Tseng B. Y. , Marvin D. A.
Published: January 2020

Functional gene 2 product was found to be necessary for fd deoxyribonucleic acid (DNA) synthesis throughout the life cycle of the virus. Bacteria which had been infected with a temperature-sensitive gene 2 mutant ceased to make virus-specific DNA when transferred to restrictive conditions at any time after infection, although current rounds of replication were completed.
Morphology and Morphogenesis of Sindbis Virus as Seen with Freeze-Etching Techniques
Authors: Brown Dennis T. , Waite Marilynn R. F. , Pfefferkorn Elmer R.
Published: January 2020

Freeze-etch electron microscope studies of the morphogenesis and morphology of Sindbis virus confirmed results obtained by other workers employing thin-sectioning techniques. The 68-nm virion was found to have a nucleocapsid 36 nm in diameter surrounded by a double-layered, unit membrane. The membranous envelope is acquired as the capsid buds through the plasma membrane of the infected cell. The freeze-etch technique also provided the following new information. (i) At any one time, budding occurs in patches rather than evenly over the cell surface. (ii) The nucleocapsid is composed of capsomers 7 nm in diameter. (iii) The capsid interacts strongly with the membrane, both prior to budding and after maturation. (iv) The 7- to 10-nm particles characteristic of the internal faces of plasma membranes, which presumably represent host membrane proteins, are present in early stages of budding but disappear as morphogenesis progresses. (v) Fusion of the cell membrane at the base of the budding virion is a two-step process; the inner leaflet fuses into a sphere before the outer one. (vi) The outer surface of the viral envelope is covered with 4-nm subunits with a center-to-center spacing of 6 nm.
Simian Virus 40 Deoxyribonucleic Acid Synthesis: Analysis by Gel Electrophoresis
Authors: Tegtmeyer Peter , Macasaet Francisco
Published: January 2020

An agarose-gel electrophoresis technique has been developed to study simian virus 40 deoxyribonucleic acid (DNA) synthesis. Superhelical DNA I, relaxed DNA II, and replicative intermediate (RI) molecules were clearly resolved from one another for analytical purposes. Moreover, the RI molecules could be identified as early or late forms on the basis of their electrophoretic migration in relation to that of DNA II. The technique has been utilized to study the kinetics of simian virus 40 DNA synthesis in pulse and in pulse-chase experiments. The average time required to complete the replication of prelabeled RI molecules and to convert them into DNA I was approximately 10 min under the experimental conditions employed.
Virus-Specific Ribonucleic Acid in the Nucleus and Cytoplasm of Rat Embryo Cells Transformed by Adenovirus Type 2
Authors: Shimada Koichiro , Fujinaga Kei , Hama Seiji , Sekikawa Kenji , Ito Yohei
Published: January 2020

Nuclei were isolated from rat embryo cells transformed by adenovirus type 2. Nuclear and cytoplasmic virus-specific ribonucleic acids (RNA) were characterized and quantitated by deoxyribonucleic acid (DNA)-RNA hybrid formation with adenovirus DNA. The results indicate that most, if not all, virus-specific RNA molecules are synthesized in the cell nucleus and subsequently transported into cytoplasm where they degrade with a half-life of 1 to 2 hr. No difference in base sequences between nuclear and cytoplasmic virus-specific RNA species can be detected by hybridization competition experiment with viral DNA.
Structural Proteins of Pichinde Virus
Authors: Ramos Blanca A. , Courtney Richard J. , Rawls William E.
Published: January 2020

Pichinde virus, a member of the arenovirus group, was found to have four polypeptides by polyacrylamide gel electrophoresis. Two components, V
I
and V
II
, had molecular weights of about 72,000, whereas V
III
had a molecular weight of 34,000. A minor component, V
IV
, had a molecular weight of about 12,000. Glucosamine was incorporated into V
II
and V
III
, suggesting that these components were glycopeptides whereas V
I
and V
IV
were polypeptides. Treatment of the virus with Nonidet P-40 removed V
III
, but V
I
and V
II
remained associated with the virus nucleic acid. This suggests a functional role of a ribonucleoprotein for V
I
and an envelope glycoprotein for V
III
. V
II
, the major glycopeptide, could function both as a membrane component and as a nucleoprotein.
Behavior of Coliphage Lambda in
Shigella flexneri
2a
Authors: Gemski P. , Alexeichik J. A. , Baron L. S.
Published: January 2020

The insensitivity of wild-type
Shigella flexneri
2a to coliphage λ is a consequence of its native genetic defect in the
malA
gene cluster. The “smooth”
S. flexneri
2a lipopolysaccharide layer affects the efficient adsorption of λ. Derivatives, capable of serving as functional hosts for λ, were obtained by repairing the
malA
lesion, enabling the expression of the
malB
-λ
rcp
region of
S. flexneri.
Introduction of a mutation into
S. flexneri
causing a “rough” lipopolysaccharide character resulted in more efficient adsorption of λ. Such
S. flexneri
hosts can be stably lysogenized and upon induction yield
gal
+
-transducing lysates. Lambda propagated on a
malA
+
rough
S. flexneri
host was restricted by
Escherichia coli
K-12 and
E. coli
B, but not by
E. coli
C. This
S. flexneri
host did not restrict λ grown on these
E. coli
strains.
Study of the Transcription and the Replication of Vesicular Stomatitis Virus by Using Temperature-Sensitive Mutants
Authors: Printz-Ané Christiane , Combard Arlette , Martinet Claire
Published: January 2020

The viral ribonucleic acids (RNA species) synthesized in HeLa cells infected with temperature-sensitive (ts) mutants and with the wild type of vesicular stomatitis virus at permissive (30 C) and nonpermissive (39.2 C) temperatures were compared by sucrose gradient centrifugation. Two ts mutants (ts 5 and ts 100) representing two separate complementation groups (respectively, groups I and IV), each concerned with viral RNA synthesis, were chosen. Mutant ts 5 failed to synthesize any RNA at 39.2 C. Under the same conditions, mutant ts 100 showed a low, but easily detectable, synthesis of RNA without characteristic peaks. The in vitro transcriptase activity was tested with mutants ts 5 and ts 100 at 39.2 C: normal activity, compared with wild-type virus, was detected with purified ts 100, but no activity was detected with purified ts 5. From all our data we conclude that mutant ts 5 is defective in transcription. The defect could be in the structural transcriptase enzyme or at the level of template for transcription. Results with mutant ts 100 were not so clear-cut. However, we suggest that this mutant is concerned with some aspect of transcription in vivo. In addition, our results lead us to postulate some linkage between transcription and replication.
Cellular Alteration by Interferon: a Virus-Free System for Assaying Interferon
Authors: Stewart William E. , De Clercq Erik , De Somer Pierre
Published: January 2020

A system is described for assaying mouse interferon without using a viral “challenge” agent. Interferon-treated L cells were destroyed by exposure to polyriboinosinic·polyribocytidylic acid [poly(I)·poly(C)], and the amount of destruction was dependent on both the concentration of interferon to which the cells were exposed and the amount of poly(I)·poly(C) used as the “challenge” material. If the amount of poly(I)·poly(C) was constant, the concentration of interferon could be determined by quantitating cell destruction 6 hr after addition of the double-stranded ribonucleic acid. In addition to eliminating the necessity for employing infectious virus for interferon assays, this system has the advantages of being quicker, easier, and more sensitive than other interferon assays. The sensitivity of the assay is related directly to the amount of poly(I)·poly(C) applied to the cells, with each fivefold increase of poly(I)·poly(C) giving about a fivefold increase of sensitivity.
Serological Analysis of the Deoxyribonucleic Acid Polymerase of Avian Oncornaviruses II. Comparison of Avian Deoxyribonucleic Acid Polymerases
Authors: Nowinski Robert C. , Watson K. F. , Yaniv A. , Spiegelman S.
Published: January 2020

Monospecific antiserum prepared against the isolated deoxyribonucleic acid (DNA) polymerase of avian myeloblastosis virus (AMV) neutralized the endogenous ribonucleic acid-instructed DNA polymerase activity of detergent-disrupted virus. The viral polymerase was serologically unrelated to the seven major structural polypeptides of AMV. Furthermore, the viral enzyme was distinguished from normal cellular DNA polymerases by serological criteria; thus, antiserum against the viral enzyme neutralized its homologous antigen but not normal cellular DNA polymerases. Neutralization by antibody of viral DNA polymerase activity was observed with all avian leukemia-sarcoma viruses tested, irrespective of viral antigenic subtype. The DNA polymerase activity of avian reticuloendotheliosis virus, and of a variety of mammalian oncornaviruses, was not neutralized by antisera against the AMV polymerase. Immunological analysis of the RSVα(O) mutant, which is deficient in DNA polymerase activity, shows this mutant to lack demonstrable polymerase antigen. Viral polymerase was identified by immunofluorescence as a cytoplasmic constituent in virus-producing chicken cells; polymerase antigen was not detected in uninfected (gs
−
) chicken cells.
Replication of the Moloney Murine Sarcoma-Leukemia Virus in XC Cells
Authors: Trowbridge Sidneye T. , Benyesh-Melnick Matilda , Biswal N.
Published: January 2020

The XC rat cell line was found to support the replication of a strain of the Moloney murine sarcoma-leukemia virus. In growth curve experiments cytopathology was paralleled by the production of murine sarcoma virus and leukemia virus progeny having the biologic, antigenic, and biophysical properties of the infecting virus.
Transcription During the Development of Bacteriophage φ29: Definition of “Early” and “Late” φ29 Ribonucleic Acid
Authors: Schachtele Charles F. , De Sain Carol V. , Anderson Dwight L.
Published: January 2020

Bacteriophage φ29 messenger ribonucleic acid (mRNA) production following infection of
Bacillus subtilis
has been analyzed. Early (
e
) φ29 RNA, made prior to the onset of phage deoxyribonucleic acid (DNA) replication and exclusively from the light (L) φ29 DNA strand, has been shown by RNA-DNA hybridization-competition experiments to be present throughout the phage latent period. No repression of
e
RNA production during φ29 development could be demonstrated. Unmodified host RNA polymerase molecules appear to be sufficient for the synthesis of
e
RNA since phage-specific RNA made in the presence of chloramphenicol hybridizes only to the L strand of φ29 DNA, and this RNA can be effectively competed during hybridization by
e
RNA. The appearance of late (
l
) φ29 RNA is coincident with the onset of viral DNA replication. This RNA consists of L DNA strand transcripts which are identical to
e
RNA and a new class of mRNAs made exclusively from the “heavy” (H) φ29 DNA strand (
l
H). Protein synthesis in infected cells is required for
l
H RNA production. Studies with the antibiotic rifamycin demonstrated that synthesis of the major φ29 structural proteins is dependent on production of
l
H RNA.
Stimulation of Aryl Hydrocarbon Hydroxylase Induction in Cell Cultures by Interferon
Authors: Nebert Daniel W. , Friedman Robert M.
Published: January 2020

In cell cultures previously treated with homologous interferon, the magnitude of antiviral activity and the degree of stimulation of aryl hydrocarbon hydroxylase induction appear to be directly related. In a highly purified mouse interferon preparation, the factor stimulating hydroxylase induction and the factor directing antiviral activity are inactivated by heating to 70 C or by treating with trypsin. Also, both activities demonstrate species specificity.
Isolation of an Infectious Ribonucleoprotein from Vesicular Stomatitis Virus Containing an Active RNA Transcriptase
Authors: Szilágyi J. F. , Uryvayev L.
Published: January 2020

A ribonucleoprotein complex (TNP) containing an active RNA polymerase was isolated from purified vesicular stomatitis virus particles. The TNP sedimented through a sucrose gradient as a single band and appeared under the electron microscope as discrete long filaments in a spiral configuration. TNP contained one major and two minor polypeptides, but not the polypeptides associated with the outer coat of vesicular stomatitis virus. BHK-21 clone 13 cells could be infected with TNP, yielding infectious virus particles.
Concentration of Herpesviruses
Authors: Smith Janet Duyckinck , de Harven Etienne
Published: January 2020

A method has been developed for the concentration of herpesviruses by negative pressure ultrafiltration through dialysis tubing. The procedure results in high titer concentrates of unaggregated, morphologically intact viral particles with a virtually quantitative recovery of infectivity.
Analysis of Simian Virus 40 DNA with the Restriction Enzyme of
Haemophilus aegyptius
, Endonuclease Z
Authors: Huang Eng-Shang , Newbold John E. , Pagano Joseph S.
Published: January 2020

Limited digestion of simian virus 40 (SV40) DNA from both small- and large- plaque strains with the restriction endonuclease Z from
Haemophilus aegyptius
yielded 10 specific fragments. The number of nucleotide pairs for each fragment, determined by co-electrophoresis with φX174 RF fragments produced by endonuclease Z, ranges from 2,050 to 80. The difference in the pattern between the large- and small-plaque strains is the disappearance of one fragment containing approximately 255 nucleotide pairs and the appearance of a new fragment with 145 nucleotide pairs. This finding can be explained either by deletions or insertions totaling 110 nucleotide pairs. Complementary RNA synthesized in vitro from the adeno-SV40 hybrid virus, strain ND-1, hybridized preferentially to four of the fragments of SV40 DNA.
Surface Antigens on Cat Leukemic Cells Induced by Feline Leukemia Virus: Area Density and Antibody-Binding Affinity
Authors: Boone Charles W. , Gordin Fred , Kawakami Thomas G.
Published: January 2020

The binding of autologous bovine antibody to feline leukemia virus-induced cell surface antigens (FeCSA) on cat leukemia cells was studied by performing certain titration procedures with a mixture of immune and normal sera labeled with different iodine radioisotopes (paired-label technique). By using plots of titration data which conformed to linear equations derived from the mass action law, we determined the following constants. (i) The density of FeCSA was 2.03 × 10
6
sites per cell, or 5,230 sites per μm
2
. (ii) The equilibrium constant of the FeCSA-antibody reaction was 2.67 × 10
7
, from which the antibody binding affinity or standard free energy of the FeCSA-antibody bond was determined to be − 10.48 kcal (−43,869.28 J) per mol. The use of the techniques described to measure the concentration of antibody in antiserum, in micrograms per milliliter, is discussed.
Synthesis of type 2 Adenovirus DNA in the Presence of Cycloheximide
Authors: Horwitz Marshall S. , Brayton Carol , Baum Stephen G.
Published: January 2020

Adenovirus type 2 DNA synthesis, either in permissive human cells or nonpermissive monkey cells, becomes independent of protein synthesis after the appearance of progeny viral DNA. In the presence of cycloheximide, semiconservative replication and initiation of progeny molecules can occur.
Infectivity and RNA Patterns as Functions of High- and Low-Dilution Passage of Murine Sarcoma-Leukemia Virus: Evidence for Autointerference Within an Oncornavirus Population
Authors: Bondurant M. C. , Hackett A. J. , Schaffer F. L.
Published: January 2020

Heterogeneity of buoyant density and RNA content of virions of Moloney murine leukemia-sarcoma complex [MSV (MLV)] was the result of passage at low dilution. Heterogeneous stocks revealed two major RNA components in the population, with the smaller component, apparent mol wt 4 × 10
6
to 5 × 10
6
, becoming predominant upon serial passage at low dilution. Concomitantly, infectivity titers of both MLV and MSV decreased upon serial passage at low dilution. MSV (MLV) passaged at high dilution retained high titers and a rather homogeneous high-molecular-weight RNA population characteristic of high-buoyant-density virions. Interference of both MLV and MSV replication was demonstrated by employing mixed inocula containing both low- and high-dilution passage stocks of MSV (MLV). In contrast to results with MSV (MLV), MLV freed of MSV by limit dilution did not show heterogeneity of buoyant density or of RNA when propagated at low dilution.
Preferred Site for Initiation of RNA Transcription by
Escherichia coli
RNA Polymerase Within the Simian Virus 40 DNA Segment of the Nondefective Adenovirus-Simian Virus 40 Hybrid Viruses Ad2
+
ND
1
and Ad2
+
ND
3
Authors: Zain B. Sayeeda , Dhar Ravi , Weissman Sherman M. , Lebowitz Paul , Lewis Andrew M.
Published: January 2020

The DNA of simian virus 40 (SV40) was transcribed into RNA by
Escherichia coli
RNA polymerase at 18 to 24 C after synchronization of the initiation of RNA synthesis. After a brief synthetic period the RNA product contained relatively large amounts of sequences derived from a limited segment of SV40 DNA. The source for this pulse-labeled RNA was found to be a portion of the segment of SV40 DNA included within the nondefective adenovirus (Ad)-SV40 hybrid viruses, Ad2
+
ND
1
and Ad2
+
ND
3
. After synthesis with [γ-
32
P
] ATP, Ad2
+
ND
1
and Ad2
+
ND
3
DNA transcripts contained an initial sequence missing from Ad2 transcripts. This sequence was identified as an initiation sequence for polymerase transcription of the SV40 DNA. Thus, there is a preferred site for initiation of in vitro transcription on the segment of SV40 DNA common to the nondefective Ad2
+
ND
1
and Ad2
+
ND
3
hybrid viruses.
Rabies Group-Specific Ribonucleoprotein Antigen and a Test System for Grouping and Typing of Rhabdoviruses
Authors: Schneider L. G. , Dietzschold B. , Dierks R. E. , Matthaeus W. , Enzmann P.-J. , Strohmaier K.
Published: January 2020

Cell-associated ribonucleoprotein (RNP) was isolated from BHK-21 cells infected with several strains of rabies and rabies-related viruses. The RNP-antigen from rabies and related viruses induced the formation of complement-fixing, precipitating, and immunofluorescent antibodies, and proved to be the group-specific antigen common to all rabies viruses. Antigens of the envelope which induce virus-neutralizing antibodies are apparently determinative for the serotype of a virus as evidenced by two-way neutralization tests. A combination of these methods seems to be a useful approach to the serological grouping and typing of rhabdoviruses.
Quantitative Determination and Location of Newly Synthesized Virus-Specific Ribonucleic Acid in Chicken Cells Infected with Rous Sarcoma Virus
Authors: Parsons J. Thomas , Coffin John M. , Haroz Richard K. , Bromley Peter A. , Weissmann Charles
Published: January 2020

A sensitive and quantitative nucleic acid hybridization assay for the detection of radioactively labeled avian tumor virus-specific RNA in infected chicken cells has been developed. In our experiments we made use of the fact that DNA synthesized by virions of avian myeloblastosis virus in the presence of actinomycin D (AMV DNA) is complementary to at least 35% of the sequences of 70
S
RNA from the Schmidt-Ruppin strain (SRV) of Rous sarcoma virus. Annealing of radioactive RNA (either SRV RNA or RNA extensively purified from SRV-infected chicken cells) with AMV DNA followed by ribonuclease digestion and Sephadex chromatography yielded products which were characterized as avian tumor virus-specific RNA-DNA hybrids by hybridization competition with unlabeled 70
S
AMV RNA, equilibrium density-gradient centrifugation in Cs
2
SO
4
gradients, and by analysis of their ribonucleotide composition. The amount of viral RNA synthesized during pulse labeling with
3
H-uridine could be quantitated by the addition of an internal standard consisting of
32
P-labeled SRV RNA prior to purification and hybridization. This quantitative assay was used to determine that, in SRV-infected chicken cells labeled for increasing lengths of time with
3
H-uridine, labeled viral RNA appeared first in a nuclear fraction, then in a cytoplasmic fraction, and still later in mature virions. This observation is consistent with the hypothesis that RNA tumor virus RNA is synthesized in the nucleus of infected cells.
Proteins Specified by Herpes Simplex Virus IX. Contiguity of Host and Viral Proteins in the Plasma Membrane of Infected Cells
Authors: Heine Jochen W. , Roizman Bernard
Published: January 2020

Artificial mixtures of plasma membrane vesicles produced by microcavitation from infected and uninfected cells band at the same density on isopycnic centrifugation in sucrose density gradient. However, after reaction with antiviral antibody, the density of the infected cell plasma membrane vesicles increases, and the infected and uninfected cell membranes are quantitatively separable on isopycnic centrifugation. Plasma membrane vesicles prepared from cells doubly labeled before and after infection with radioactive amino acids and reacted with antibody banded at a high density. Polyacrylamide gel electropherograms show that the vesicles reacted with antibody consist of both host- and virus-specific membrane proteins. Microcavitation does not disrupt viral envelopes since infectivity is not affected by this procedure. We conclude that viral and cellular proteins in the plasma membrane preparations are contiguous.
Host-Controlled Modification and Restriction of Bacteriophage T7 by
Escherichia coli
B
Authors: Eskin Barnet , Lautenberger James A. , Linn Stuart
Published: January 2020

T7 phage resists
Escherichia coli
B host-controlled modification and restriction in vivo, but its DNA carries roughly five sites which are susceptible to the purified enzymes.
Order of Injection of T7 Bacteriophage DNA
Authors: Pao Chia-Chu , Speyer Joseph F.
Published: January 2020

The deoxyribonucleic acid (DNA) corresponding to the left-hand end of the genetic map is injected first in T7 phage infection. The order was deduced by use of marker rescue experiments to see which genes are still injected after the double-stranded DNA chain is broken by X rays. The treatment causes a selective loss of genes located on the right side of the map. Presumably, this corresponds to the tail end of normally injected DNA, and X rays cut off this end.
Isolation of an RD-114-Like Oncornavirus from a Cat Cell Line
Authors: Fischinger Peter J. , Peebles Paul T. , Nomura Shigeko , Haapala Daniel K.
Published: January 2020

A clone of cells derived from a continuous line of cat cells (CCC) spontaneously produced an RNA C-type virus (CCC virus) which did not have the group-specific antigen of the standard strains of feline leukemia viruses but did have that of the RD-114 virus. Single-hit infection of a virus yielding CCC cell with only the feline leukemia virus pseudotype of murine sarcoma virus [MSV(FeLV)] resulted in the release of a pseudotype of MSV coated with the CCC virus envelope. Host range, transmission of virus, helper functions, interference properties, and specific neutralization showed that the CCC and the RD-114 isolates as well as their respective MSV pseudotypes are closely similar if not identical. Parental, virus-negative cells frozen before the existence of RD-114 were chemically induced to yield CCC-like virus de novo. Infection of susceptible human cells with the chemically induced virus resulted in interference with the CCC virus pseudotype of MSV but not with the FeLV pseudotype of MSV.
Growth Characteristics of Cytomegalovirus in Human Fibroblasts with Demonstration of Protein Synthesis Early in Viral Replication
Authors: Furukawa Toru , Fioretti Armanda , Plotkin Stanley
Published: January 2020

In high-multiplicity infection of human fibroblasts, human cytomegalovirus of WI-38 human diploid cells produced early cell rounding 6 to 24 h after inoculation. This early cell rounding was caused only by inoculation with infectious virions. Inhibitors of protein synthesis, but not DNA inhibitors, prevented this cytopathic effect. Apparently, a new protein is synthesized in infected fibroblasts from about 2 h postinoculation. Infectivity of cell-associated and supernatant infectious virus reached maximal levels at 5 to 7 and 10 days postinoculation, respectively. Synthesis of DNA, infectious virus, complement-fixing antigen, and precipitin antigen all began between 24 and 48 h, with the bulk of synthesis occurring 48 to 96 h postinoculation.
Antigenic Determinants of Infective and Inactivated Human Rhinovirus Type 2
Authors: Lonberg-Holm K. , Yin Fay H.
Published: January 2020

Treatment of human rhinovirus type 2 (HRV 2) virions at pH 5, at 56 C or in 2 M urea, produces one or both of two types of subviral particles. These subviral particles sediment at 135
S
or at 80
S
and both share what have been designated as C-antigenic determinants; the determinants of native virions have been designated D. These sets of determinants have been contrasted by the techniques of immunodiffusion, complement fixation, and serum blocking, and the results indicate that many or most of the D-determinants are lost in the conversion to C antigenicity. Some of the HRV 2 C-determinants also react, in immunodiffusion and in complement fixation tests, with antisera produced against HRV 1A virions. The inverse reaction has also been detected by complement fixation. Purified natural top component (NTC) of HRV 2 contains C- and, to a lesser extent, D-determinants. The D-determinants of NTC are also, like those of virions, lost upon treatment at pH 5. These results are discussed in terms of a conformational model for the D- to C-antigenic conversion.
Multiple and Specific Initiation of T4 DNA Replication
Authors: Howe Chin C. , Buckley Patrick J. , Carlson Karin M. , Kozinski Andrzej W.
Published: January 2020

Partially replicated T4 DNA molecules (PRM) whose parental or progeny DNA was labeled with bromodeoxyuridine BUdR was analyzed by gradual shearing followed by CsCl banding of the sheared product. Analysis of PRM containing 18-μm replicated DNA showed that each replicated region was 3- to 6-μm long, indicating three to 6 replicative sites per molecule. Analysis of PRM containing 9-μm replicated DNA similarly indicated two to three replicated regions per molecule. DNA from the replicated regions of PRM containing 10-μm replicated DNA (“donor”) was hybridized to DNA from mature phage (“recipient”), and the resulting hybrid was subjected to digestion with exonuclease I. The extent of protection of the recipient and more efficient self-annealing of progeny fragments from PRM indicated that the replicated regions represented 8 to 10 nonrandom locations of the genome. Possible significance of multiple sites for initiation of DNA replication is discussed.
DNA-Mediated Prophage Induction in
Bacillus subtilis
Lysogenic for φ105c4
Authors: Garro Anthony J.
Published: January 2020

Prophage was induced when strains of
Bacillus subtilis
168 lysogenic for φ105c4 were grown to competence and exposed to specific bacterial DNAs. The time course of phage production was similar to that observed for mitomycin C induction of wild-type prophage. Induction was directly dependent upon DNA concentration up to levels which were saturating for the transformation of bacterial auxotrophic markers. The extent of induction varied with the source of DNA. The burst of phage induced by DNA isolated from a W23 strain of
B. subtilis
was fivefold less than that induced by DNA from
B. subtilis
168 strains, while
B. licheniformis
DNA was completely inactive. This order of inducing activity was correlated with the ability of the respective DNAs to transform auxotrophic markers carried by one of the φ105c4 lysogens. Differences in inducing activity also were observed for different forms of φ105 DNA. The DNAs isolated from φ105 phage particles and φ105c4 lysogens were inactive, whereas DNA from cells lysogenized by wild-type φ105 induced a burst of phage. When tested for transforming activity, however, both φ105c4 and φ105 lysogen DNAs were equally effective. An induction mechanism which involves recombination at the prophage insertion site is proposed to explain these differences.
Cytotoxicity of Adenovirus-Antibody Aggregates: Sensitivity to Different Cell Strains, and Inhibition by Hexon Antiserum and by Complement
Authors: Kjellén Lars , Ankerst Jaro
Published: January 2020

Adenovirus-antibody aggregates under defined conditions are cytotoxic in vitro. All members of adenovirus groups I, II, and III caused toxicity upon aggregation. The toxicity of the clusters is exerted by the virions. Toxicity is temperature dependent and may be caused by a mechanism similar to that used in viral penetration. Cells permitting direct viral penetration were all sensitive to the toxic aggregates. The toxicity seems to be related to hexon antigens on the surface of the virions since antihexon sera neutralized the toxicity. No evidence was obtained showing that pentons are required for this kind of cytotoxicity. Adenovirus types 3, 5, and 9 were used in the experiment. Cytotoxicity was estimated by the
51
Cr release assay. Complement factors could be excluded as mediators of the cytolytic reactions. Instead, complement was shown to prevent the formation of toxic aggregates or to neutralize the toxicity of preformed ones.
Transcription of Simian Virus 40 II. Hybridization of RNA Extracted from Different Lines of Transformed Cells to the Separated Strands of Simian Virus 40 DNA
Authors: Ozanne Brad , Sharp Phillip A. , Sambrook Joe
Published: January 2020

The amount of simian virus 40 (SV40) DNA present in various SV40-transformed mouse cell lines and “revertants” isolated from them was determined. The number of viral DNA copies in the different cell lines ranged from 1.35 to 8.75 copies per diploid quantity of mouse cell DNA and from 2.2 to 14 copies per cell. The revertants had the same number of viral DNA copies per diploid quantity of mouse cell DNA as their parental cell lines. (However, they showed an increased number of viral DNA copies per cell due to their increased amount of DNA.) By using separated strands of SV40 DNA, the extent of each DNA strand transcribed into stable RNA species was determined for the transformed and “revertant” cell lines. From 30 to 80% of the “early” strand and from 0 to 20% of the “late” strand was present as stable RNA species in the cell lines tested. There was no alteration in the pattern of the stable viral RNA species present in three concanavalin A-selected revertants, whereas in a fluorodeoxyuridine-selected revertant there appeared to be less viral-specific RNA present in the cells.
Hydroxyapatite Chromatography and Formamide Denaturation of Adenovirus DNA
Authors: Tibbetts Clark , Johansson Katarina , Philipson Lennart
Published: January 2020

Denatured adenovirus DNA was retained by hydroxyapatite columns under conditions generally used for selective retention of double-stranded DNA, probably due to several partially complementary sequences within single-stranded DNA. It was found that addition of formamide reduced the fraction of sonically treated, denatured adenovirus DNA bound to hydroxyapatite from about 30% to less than 1%. This led to a study of the effect of formamide on the melting temperature (

T
m

) of double-stranded DNA in solution or bound to hydroxyapatite. The

T
m

of DNA decreases 0.56 C/1% formamide, a value determined in buffered solutions with purified formamide.
Processing of Adenovirus 2-Induced Proteins
Authors: Anderson C. W. , Baum P. R. , Gesteland R. F.
Published: January 2020

Analysis of
35
S-methionine-labeled extracts of adenovirus 2-infected KB cells revealed 22 virus-induced polypeptide components. Most proteins of the virion were easily detected in extracts of whole cells labeled for short periods between 15 and 30 h after infection; however, several virion components were conspicuously absent. Radioactivity appeared in two of these virion components during a chase in nonradioactive medium, and this appearance was paralleled by a decrease in the radioactivity associated with two nonvirion adenovirus-induced proteins, results which imply precursor-product relationships for these components. Comparison of one of the chasable adenovirus-induced components (designated P-VII; mass of 20,000 daltons) and the major core protein (VII; mass of 18,500 daltons) of the virion showed that they have four common methionine-containing tryptic peptides; P-VII has an additional methionine residue which is not found in the major core protein. We propose that at least two of the adenovirus 2 virion components are derived by the cleavage of higher molecular weight precursor polypeptides.
Replication of Dengue Virus Type 2 in
Aedes albopictus
Cell Culture
Authors: Sinarachatanant Pantipa , Olson Lloyd C.
Published: January 2020

The replication of type 2 dengue (D-2) virus in
Aedes albopictus
(Aal) mosquito cell cultures differed from that in vertebrate (LLC-MK2) rhesus monkey kidney cells. Virus readily replicated in Aal cells at either 30 or 37 C, but had no apparent effect on the host cell. Persistent infection was established with continual virus production for at least 6 months, although the virulence of progeny virus for both suckling mice and LLC-MK2 cells became attenuated. Density gradient analysis of infected Aal cell supernatant products indicated that only complete virus was released, in contrast to infected LLC-MK2 cells which also released incomplete virus. The surface antigens of the virus produced in Aal cells appeared to be considerably modified in that antiserum to vertebrate cell-produced D-2 virus did not block hemagglutination, whereas anti-Aal cell antiserum did. Virus infectivity could be neutralized by the antiserum to D-2 virus grown in vertebrate cells, however. Virus produced in LLC-MK2 cells did not demonstrate a similar host-cell modification. These results may reflect a difference in the mechanism by which D-2 virus matures in Aal cells.
Phosphorylation of Animal Virus Proteins by a Virion Protein Kinase
Authors: Silberstein Harvey , August J. Thomas
Published: January 2020

Compared with several other enveloped viruses, purified virions of frog virus 3 contained a relatively high activity of a protein kinase which catalyzed the phosphorylation of endogenous polypeptides or added substrate proteins. Virions also contained a phosphoprotein phosphatase activity which released phosphate covalently linked to proteins. It was possible to select reaction conditions where turnover of protein phosphoesters was minimal, as the phosphatase required Mn
2+
ions for activity whereas the protein kinase was active in the presence of Mg
2+
ions. Electrophoretic studies in polyacrylamide gels containing sodium dodecyl sulfate indicated that at least 10 of the virion polypeptides were phosphorylated in the in vitro protein kinase reaction. Characterization of these phosphoproteins demonstrated that the phosphate was incorporated predominantly in a phosphoester linkage with serine residues. The protein kinase was solubilized by disrupting purified virions with a nonionic detergent in a high-ionic-strength buffer and was separated from many of the virion substrate proteins by zonal centrifugation in glycerol gradients. The partially purified protein kinase would phosphorylate polypeptides of many different animal viruses, and maximal activity was not dependent on added cyclic nucleotides. These properties distinguished the virion protein kinase from a well characterized cyclic AMP-dependent protein kinase which phosphorylated viral proteins only to a small extent.
Helper-Dependent Properties of Friend Spleen Focus-Forming Virus: Effect of the
Fv-1
Gene on the Late Stages in Virus Synthesis
Authors: Eckner Robert J.
Published: January 2020

Co-infection of neonatal BALB/c mice with Friend virus (FV) complex (containing defective spleen focus-forming virus [SFFV] and endogenous N-tropic leukemia-inducing helper virus [LLV-F]) and B-tropic Tennant leukemia virus (TenLV) resulted in the inhibition of LLV-F by the
Fv-1

b

gene and recovery of a TenLV pseudotype of SFFV, abbreviated SFFV(TenLV). The host range of this pseudotype was B-tropic, since SFFV(TenLV) was 10 to 100 times more infectious for B-type (
Fv-1

bb

) than for N-type (
Fv-1

nn

) mice. The similar patterns of neutralization of N-tropic and B-tropic SFFV by type-specific murine antisera suggested that the difference in infectivity between these two SFFV preparations did not reside in envelope determinants. Rather, helper control of SFFV's host range was only apparent and dependent upon the ability of associated virus to provide a helper function for late stages in SFFV synthesis. Early stages in SFFV's infectious cycle were shown to be helper independent. The
Fv-1
gene did not act at the level of the cell membrane to effectively restrict SFFV infection, since SFFV-induced transformed cells could be detected in the absence of spleen focus formation and SFFV synthesis. Further, the generation of these transformed cells by SFFV followed a one-hit, dose-response pattern, suggesting that SFFV-induced cell transformation is helper independent. Finally, restriction of helper function by
Fv-1
may be an intracellular event, because both SFFV and its associated LLV-F helper share common envelope determinants and presumably adsorb onto and penetrate target cells with equal efficiency.
Expression of Endogenous RNA C-Type Virus Group-Specific Antigens in Mammalian Cells
Authors: Stephenson John R. , Aaronson Stuart A.
Published: January 2020

Highly sensitive and specific radioimmunoassays are described for quantitation of the intraspecies determinants of several mammalian C-type viral group-specific (gs) antigens. An interspecies (gs-3) immunoassay has been developed which has both the broad reactivity and great sensitivity necessary for detection of C-type viruses where intraspecies gs assays are not available. By using these immunoassays, the expression of endogenous virus-specified gs antigens in mammalian cells of different species has been studied. Whereas mouse gs antigen was clearly detectable in tissue culture cells of several mouse strains, the respective gs antigens of rat, cat, Chinese hamster, woolly monkey, and gibbon ape were not detectable in cells of those species, using assays of comparable sensitivity. Thus, differences exist in the level of endogenous virus expression in cells of different mammalian species.
Proposed Nomenclature for Mutants of Adenoviruses
Authors: Ginsberg Harold S. , Williams James F. , Doerfler Walter H. , Shimojo Hiroto
Published: January 2020

In accord with the nomenclature proposed for mutants of simian virus 40 the same rules, with minor modifications, are recommended for naming mutants of adenoviruses. It is further suggested that these rules, which pertain to a system of classification based primarily upon complementation analysis, also be applied to mutants of other DNA-containing animal viruses.