bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of a Latent Measles Virus Infection in Hamster Cells
Authors: Haspel Martin V. , Knight Paul R. , Duff Ronald G. , Rapp Fred
Published: January 2020

The characteristics of infectious measles virus released from latently infected hamster embryo fibroblast cells are described. Low levels of virus were released spontaneously when the cultures were incubated at 37 C; this phenomenon was observed 19 passages after the cells had been exposed to the virus and has continued through cell passage 45. The virus yield could be significantly increased by cocultivation of the hamster cells with BSC-1 cells or incubation of the latently infected cells at 33.5 C rather than at 37 C. Measles virus released after cocultivation demonstrated increased cytopathology in cell culture and reduced temperature sensitivity when compared to the virus released at 33.5 C. After cell passage 45, there was an increase in spontaneous release of virus. However, the viruses recovered by cocultivation or temperature release after cell passage 45 were nearly identical. These observations suggest a possible mechanism for measles virus activation in cells latently infected with this virus.
Partial Transcription of Murine Type C Viral Genomes in BALB/c Cell Lines
Authors: Benveniste Raoul E. , Todaro George J. , Scolnick Edward M. , Parks Wade P.
Published: January 2020

The mouse cell line, BALB/c 3T3, and its derivatives transformed either spontaneously or by treatment with a variety of external agents, were analyzed for cytoplasmic RNA complementary to DNA products prepared from the Kirsten strain of murine sarcoma-leukemia virus, and from an endogenous type C virus of BALB/c 3T3. Although none of these cell lines spontaneously releases complete type C virions, they all contain RNA which is partially homologous to a portion of the 35
S
RNA isolated from these viruses. The parental cell line, BALB/c 3T3, contains a low level of viral-related RNA, and there is an increased amount of this RNA in some of the transformed cells. The RNA detected represents only a fraction of the viral RNA found in virus-producing cells. The formation of RNA:DNA hybrids was detected by equilibrium centrifugation in Cs
2
SO
4
density gradients and by analysis with a single-strand-specific nuclease from
Aspergillus oryzae
. Viral DNA products prepared either from an endogenous reaction with whole virus in the presence of actinomycin D or from purified 70
S
viral RNA as template using avian myeloblastosis virus DNA polymerase yield comparable data. In addition, all of the BALB/c lines examined produce detectable levels of murine type C virus group-specific antigen.
Studies of Nondefective Adenovirus 2-Simian Virus 40 Hybrid Viruses VIII. Association of Simian Virus 40 Transplantation Antigen with a Specific Region of the Early Viral Genome
Authors: Lewis Andrew M. , Rowe Wallace P.
Published: January 2020

Two of the five nondefective adenovirus 2 (Ad2)-simian virus 40 (SV40) hybrids induce SV40 transplantation resistance in immunized hamsters. These two hybrids, Ad2
+
ND
2
and Ad2
+
ND
4
, contain 32 and 43% of the SV40 genome, respectively. The pattern of induction of SV40 transplantation antigen (TSTA) by the various hybrids differentiates TSTA from both SV40 U and T antigens. Since the SV40 RNA induced by both these hybrids is early SV40 RNA, these findings confirm that TSTA is an early SV40 function. By combining available data on SV40 antigen induction by these hybrids with electron microscopy heteroduplex mapping studies, the DNA segment responsible for the induction of SV40 TSTA can be inferred to lie in the region between 0.17 and 0.43 SV40 units from the site on the SV40 chromosome cleaved by
E. coli
R
1
restriction endonuclease.
Transcription Unit Mapping in Bacteriophage T7 I. In Vivo Transcription by
Escherichia Coli
RNA Polymerase
Authors: Bräutigam Alan R. , Sauerbier Walter
Published: January 2020

Premature termination of transcription at UV lesions in DNA permits a study of the sequential order of transcription by
E. coli
RNA polymerase of the genes in the early region of T7. This analysis is extended to the transcription by
E. coli
polymerase of the late region of T7 by deleting the early terminator. The results demonstrate the existence of a single large transcription unit spanning the early region, with a promotor located at the left end of the T7 genome. Furthermore, there are no initiation sites for
E. coli
RNA polymerase in the late region. When
E. coli
polymerase transcribes the late region, it does so exclusively by initiation at the early promotor.
Induction of Cellular DNA Synthesis by the Nondefective Adenovirus 2-Simian Virus 40 Hybrid Viruses
Authors: Schnipper Lowell E. , Lewis Andrew M. , Levine Arthur S.
Published: January 2020

Induction of cellular DNA synthesis by the nondefective adenovirus 2-simian virus 40 hybrid viruses was examined in monkey and hamster cells. It was not possible to discriminate the effects of the hybrid viruses from those of wild-type adenovirus 2.
Presumptive D2a Point Mutants of Bacteriophage T4
Authors: Bruner Robert , Solomon Donald , Berger Timothy
Published: January 2020

Mutants of bacteriophage T4 have been isolated that show phenotypes seen previously with those
r
II deletions that extend into the nearby D2a region. Analysis indicates that
r
II mutations are not necessary in order to get the D2a phenotypes.
Isolation and Characterization of a Bacteriophage of
Arthrobacter globiformis
Authors: Einck K. H. , Pattee P. A. , Holt J. G. , Hagedorn C. , Miller J. A. , Berryhill D. L.
Published: January 2020

A bacteriophage which reproduces on
Arthrobacter globiformis
ATCC 8010 was isolated from soil. This bacteriophage, designated φAG8010, propagates either in soft agar or broth cultures of the host. Because of a slow adsorption rate, neither the latent period nor burst size was determined. The mature virion belongs to Bradley's group B and exhibits a hexagonal head measuring 69 nm (length) by 60 nm (width) attached to a sheathless tail 120 nm long. The buoyant density of the mature virion is 1.534 g/cm
3
. The mature virion contains double-stranded DNA with a buoyant density of 1.722 g/cm
3
(equivalent to 63.3% G + C). Of 14 strains (representing 13 species) of
Arthrobacter
examined, including
A. globiformis
ATCC 4336, only
A. globiformis
ATCC 8010 supported replication of φAG8010.
Antigenic Components of Group A Arbovirus Virions
Authors: Dalrymple J. M. , Vogel S. N. , Teramoto A. Y. , Russell P. K.
Published: January 2020

Three group A arboviruses, Sindbis (SIN), western (WEE) and eastern equine encephalitis (EEE), were selectively degraded with a nonionic detergent to yield a core particle and a soluble envelope component. Antigenic analysis by using radioimmune precipitation techniques revealed marked antigenic similarity among the core particles of the three viruses. The soluble envelope component exhibited antigenic specificity similar to that of intact virions. A close relationship between SIN and WEE envelopes was shown, whereas EEE envelope antigen appeared antigenically specific. These data indicate that nucleocapsids of group A arboviruses contain an antigenic determinant common to the group; the envelope contains virus-specific antigens as well as antigens which relate members of a subgroup.
Strandedness and Complementarity of DNA from Long-Term RNA-Dependent DNA Polymerase Reactions of Soehner-Dmochowski Murine Sarcoma Virus
Authors: East James L. , Knesek John E. , Allen Patton T. , Dmochowski Leon
Published: January 2020

The DNA product of the endogenously instructed RNA-dependent DNA polymerase reaction of murine sarcoma virus continued to be synthesized for as long as 64 h in the presence of 0.008% Triton X-100. Higher detergent concentrations and actinomycin D inhibited DNA product synthesis. The DNA product from long-term polymerase reactions consisted of small DNA fragments as shown by sedimentation in alkaline sucrose gradients. The enzymatic DNA product was separated into a slow sedimenting fraction and a fast sedimenting fraction by rate-zonal centrifugation. Fast sedimenting DNA was the predominant fraction made in viral polymerase reactions containing 262 mM NaCl. By using a combination of S-1 nuclease and pancreatic RNase A, the amount of single-stranded DNA, double-stranded DNA, and DNA-RNA hybrid present in the slow-sedimenting and fast-sedimenting fractions was determined. Under standard polymerase conditions of 70 mM NaCl, single-stranded DNA was the major form of DNA found in both fractions. In contrast, the prevalent form of DNA made in the presence of 262 mM NaCl was DNA-RNA hybrid. Hybridization studies in which either S-1 nuclease or pancreatic RNase A was used to measure hybrid formation demonstrated not only that the DNA product was complementary in base sequence to the RNA genome, but also that at least 79 to 84% of the RNA genome was transcribed into complementary DNA.
Cell Surface Antigens Associated with Murine Leukemia Virus: Definition of the G
L
and G
T
Antigenic Systems
Authors: Nowinski Robert C. , Peters Elizabeth D.
Published: January 2020

Two new serological specificities were identified on the surface of murine leukemia virus (MuLV)-infected cells by direct and absorption immunofluorescence tests. Both antigens were detected with antisera prepared in rats that were growing transplants of syngenic MuLV-induced leukemias. Antigen G
L
was defined with the AKR leukemia K36 as the test cell; antigen G
T
was defined with the W/Fu leukemia C58(NT)D as the test cell. G
L
and G
T
antigens were serologically and genetically independent of the MuLV-induced Gross and G
IX
cell-surface antigens. G
L
and G
T
antigens were found in normal lymphoid cells of mice from high-leukemic strains, but not in lymphoid tissues of mice from most low-leukemic strains. Tumors and leukemias of mice of low-leukemic strains often were G
L
and G
T
positive. Similarly, infection of normal cells with MuLV resulted in expression of G
L
and G
T
. With ferritin-labeled antibody the G
L
and G
T
antigens were observed on virus-free segments of the cell surface. Genetically, G
L
and G
T
antigens were each controlled by two dominant unlinked genes in AKR mice; these same antigens were each controlled by three or more dominant unlinked genes in C58 mice. Penetrance of G
L
and G
T
regulatory genes was dependent upon the Fv-1 genotype of the host. Expression of G
L
antigen was closely associated with virus production, whereas expression of G
T
antigen was less closely associated.
Simian Virus 40-Host Cell Interactions. I. Temperature-Sensitive Regulation of SV40 T Antigen in 3T3 Mouse Cells Transformed by the
ts
*
101
Temperature-Sensitive Early Mutant of SV40
Authors: Robb James A.
Published: January 2020

BALB/3T3 and Swiss/3T3 mouse cells transformed at permissive temperature (33 C) by the early temperature-sensitive mutant of simian virus 40 (SV40),
ts
*
101
, exhibited a temperature-dependent modulation of SV40 tumor (T) antigen as assayed by immunofluorescence. The percentage of T antigen-positive nuclei in
ts
*
101
transformed cells was reduced at restrictive temperature (39 C) when compared to 33 C and to wild-type SV40 transformed cells at either 33 C or 39 C. The percentage of T antigen-positive nuclei in
ts
*
101
transformed cells returned to the 33 C control level when the cells were shifted from 39 to 33 C. The
ts
*
101
transformed cells could be superinfected with wild-type, but not
ts
*
101
, virions at 39 C as assayed by an increase in T antigen-positive nuclei.
Synthesis of Bacteriophage and Host DNA in Toluene-Treated Cells Prepared from T4-Infected
Escherichia coli:
Role of Bacteriophage Gene D2a
Authors: Elliott Joel , Richter Christoph , Souther Arthur , Bruner Robert
Published: January 2020

We investigated the synthesis of DNA in toluene-treated cells prepared from
Escherichia coli
infected with bacteriophage T4. If the phage carry certain
r
II deletion mutations, those which extend into the nearby D2a region, the following results are obtained: (i) phage DNA synthesis occurs unless the phage carries certain DNA-negative mutations; and (ii) host DNA synthesis occurs even though the phage infection has already resulted in the cessation of host DNA synthesis in vivo. The latter result indicates that the phage-induced cessation of host DNA synthesis is not due to an irreversible inactivation of an essential component of the replication apparatus. If the phage are D2a
+
, host DNA synthesis in toluene-treated infected cells is markedly reduced; phage DNA synthesis is probably also reduced somewhat. These D2a effects, considered along with our earlier work, suggest that a D2a-controlled nuclease, specific for cytosine-containing DNA, is active in toluene-treated cells.
Characterization of Nuclear Polyhedrosis Virus DNAs
Authors: Summers Max D. , Anderson David L.
Published: January 2020

The nuclear polyhedrosis virus DNAs characterized and compared in this study consist of the singly-enveloped nucleocapsids (SNPV) of
Trichoplusia ni
and the bundles of nucleocapsids common to a single envelope (MNPV) from
Spodoptera frugiperda
and
Rachiplusia ou
. The SNPV and MNPV DNAs are very similar in hydrodynamic properties and molecular weights. In addition, the NPV DNAs are similar in size to those extracted from the granulosis viruses that infect
T. ni
and
S. frugiperda
. As isolated from purified virus or directly from occluded virus, the nuclear polyhedrosis virus DNAs consist of a mixture of about 20 to 30% double-stranded covalently closed molecules and approximately 60% relaxed circles, with less than 10% in linear duplex form. The molecular weights of all nuclear polyhedrosis virus DNAs as compared in this study are slightly smaller than those of T4 bacteriophage DNA and perhaps slightly smaller than those of the granulosis virus DNAs. The best estimates of these molecular weights by neutral sucrose sedimentation for the nuclear polyhedrosis viruses range from 90 to 100 × 10
6
relative to a size of 108 × 10
6
for T4 DNA. The base compositions of the nuclear polyhedrosis viruses that infect
T. ni
and
S. frugiperda
are compared with the respective insect host DNAs.
Biosynthesis of the Sindbis Virus Carbohydrates
Authors: Sefton Bartholomew M. , Burge Boyce W.
Published: January 2020

The sequence in which sugars are added to the Sindbis virus glycoproteins was studied. Infected cells contain three glycosylated virus-specific proteins: the two virion glycoproteins and the immediate precursor to the smaller virion glycoprotein. Larger Sindbis-specific proteins are not glycosylated. The cell-associated forms of both of the virion glycoproteins contain glucosamine, mannose, galactose, and fucose. The glycosylated precursor contains only glucosamine, mannose, and some galactose. The conversion of precursor to virion protein involves both the addition of galactose and fucose and the loss of mannose. The apparent extent of glycosylation of each virus-specific protein is not influenced by the host cell.
Defective Interfering Particles of Poliovirus IV. Mechanisms of Enrichment
Authors: Cole Charles N. , Baltimore David
Published: January 2020

Infection of HeLa cells by mixtures of standard poliovirus and defective, interfering (DI) poliovirus particles leads to a higher ratio of DI particles in the progeny than in the inoculum. The extent of this enrichment could be varied by various manipulations of the co-infected cells. At any time during the infection cycle, virions made within short times after addition of radioactive uridine were hyperenriched in DI particles; this transient hyperenrichment fell to the equilibrium enrichment level within 45 min after uridine addition. A shift of the temperature of infection from 37 to 31 C also led to a hyperenrichment of DI particles and pulse-labeling revealed a superimposed transient hyperenrichment. By contrast, cells continuously infected at 31 C showed a severe decrement in DI particles apparently because poliovirus DI particles behave as cold-sensitive mutants for RNA synthesis. Cycloheximide treatment early in the infection cycle also led to hyperenrichment. Study of the cycloheximide effect showed that the drug acted as if to change the input ratio of standard to DI particles. These effects on enrichment can be explained as aspects of two different phenomena: enrichment due to preferential DI RNA synthesis and enrichment due to preferential encapsidation of DI RNA. Both mechanisms probably play a role in the normal level of enrichment.
RNA-DNA Covalent Bonds Between the RNA Primers and the DNA Products Formed by RNA Tumor Virus DNA Polymerase
Authors: Flügel Rolf M. , Rapp Ulf , Wells Robert D.
Published: January 2020

Initiation of DNA synthesis by endogenous RNA primer molecules was studied with three different RNA tumor viruses. The influence of the method of virus disruption on the observed RNA-DNA bonds was ascertained. Ether disrupted virions of both murine leukemia virus (MuLV) and the B77 strain of avian sarcoma virus (B77 virus) have rC-dC and rA-dA covalent linkages between RNA primers and newly synthesized DNA. None of the 14 other possible bonds were formed. Ether-disrupted virions of avian myeloblastosis virus (AMV) have rU-dC and rA-dA linkages. In contrast, work reported herein and from other laboratories shows that Nonidet P-40 (NP-40)-disrupted virions of all three viruses have only the rA-dA junction. Studies with virus particles which were first disrupted with ether and then treated with NP-40 indicated that the detergent treatment disallowed the formation of the ribopyrimidine-dC internucleotide bond. The same transfers are found with AMV in the presence or absence of actinomycin D, where only single-stranded DNA is formed. This finding is consistent with the notion that virtually all of the significant primers have been recognized. In contrast to mature virions, transfer experiments with ether-disrupted early harvest (5 min) MuLV showed only the rC-dC bond; the rA-dA bond was absent. The short-time harvest contains a significantly higher proportion of infectious virions than 24-h harvests. Also, since the RNA from early harvest virus is appreciably more homogenous than the RNA of mature MuLV, it is concluded that the ribopyrimidine-dC linkage is the more significant initiation event from a biochemical standpoint.
Sendai Virion Transcriptase Complex: Polypeptide Composition and Inhibition by Virion Envelope Proteins
Authors: Marx Preston A. , Portner Allen , Kingsbury D. W.
Published: January 2020

Sendai virions, disrupted in 2% Triton X-100 in 1 M KCl, were separated into nucleocapsids and envelope proteins by centrifugation. The nucleocapsids, representing 46% of the virion proteins, had a buoyant density of 1.29 gm/cm
3
in D
2
O sucrose. RNA-dependent transcriptase activity associated with them had a ninefold greater specific activity than transcriptase assayed in unfractionated detergent-disrupted virions. These enzyme-active nucleocapsids contained only two polypeptides, the largest virion polypeptide (molecular weight 75,000) and the nucleocapsid structure unit (molecular weight 60,000). Virion envelope proteins, either glycoproteins or nonglycosylated matrix protein, inhibited nucleocapsid-associated polymerase activity; brief heat denaturation abolished their inhibitory activity. Yeast RNA stimulated nucleocapsid-associated enzyme, suggesting that stimulatory polyanions act at the enzyme-template level.
Analysis of Bacteriophage φ29 Gene Function: Protein Synthesis in Suppressor-Sensitive Mutant Infection of
Bacillus subtilis
Authors: Anderson Dwight L. , Reilly Bernard E.
Published: January 2020

Phage φ29 suppressor-sensitive (
sus
) mutants of 14 cistrons have been examined for production of
14
C-labeled viral-specific proteins in restrictive infections of
Bacillus subtilis.
Proteins specified by four cistrons (H, J, L, and N) have been resolved and identified by sodium dodecyl sulfate gel electrophoresis and autoradiography, and fragments of the normal polypeptides were detected. Mutants of six cistrons (C, D, E, F, I, and M) demonstrated two or more missing bands in the gel profiles, and thus some of these gene products may have regulatory functions. Mutation was detected in at least five genes coding for low-molecular-weight proteins, but a conditionally lethal mutant in only one of these genes has been isolated. Preliminary evidence that a precursor protein is cleaved to generate the neck appendage structural protein and a low-molecular-weight product has been obtained.
Localization of Membrane Protein Synthesized After Infection with Bacteriophage T4
Authors: Fletcher Gail , Wulff Judith L. , Earhart C. F.
Published: January 2020

The synthesis of membrane protein after infection with bacteriophage T4 was examined. Protein constituents of both the cytoplasmic and outer membrane are made during the infective cycle. In addition, newly synthesized membrane protein is found in material which has a buoyant density greater than that of either of the two host membrane fractions. Polyacrylamide gel analyses and solubilization studies using the detergent Sarkosyl indicate that synthesis of most of the membrane proteins made during the first 5 min of infection is directed by bacterial genes. New membrane proteins synthesized at times greater than 6 min after infection appear to be distinct from those of the host, and new proteins of the outer membrane are different from those of the inner. Proteins in the new dense membrane fraction are similar to those of the outer membrane.
Murine Virus-Induced Proteins Synthesized by Hamster Tumor Cells Transformed by, But Not Producing, Murine Sarcoma Virus
Authors: Ikegami Nobuko , Gomatos Peter J.
Published: January 2020

The 8303 hamster tumor cells transformed by Moloney strain of murine sarcoma virus (M-MSV), but which do not produce virus, do contain murine virus-induced proteins. The virus-induced proteins within the cell were identified either as free proteins or in association with membranous material, including the plasma membrane. In addition, some were excreted by the 8303 hamster tumor cells into the growth medium. Most virus-induced proteins were larger than 68,000 daltons, and they did not dissociate into components of smaller size in the presence of detergent and a reducing agent. A small amount of virus-induced protein with a molecular weight of less than 20,000 was also found in the hamster tumor cells. No virus-specific proteins with the identical antigenic specificity or size of the major internal group specific antigen (molecular weight about 30,000) of the murine leukemia viruses were present in these cells. There is a common cell surface antigen present in three other tumor cell lines, both virus-producing and non-virus-producing, identical in reactivity to that of the murine virus-induced antigen of the 8303 hamster tumor cell. This antigen is not present on the cell surface of normal mouse embryo cells.
Preliminary Observations Pertaining to Polyadenylation of Rhinovirus RNA
Authors: Nair C. N. , Owens M. J.
Published: January 2020

Human rhinovirus type 14 contained polyadenylated RNA. Virus growth in HeLa cells was inhibited by cordycepin or polyuridilic acid and stimulated by polyadenylic acid. Polyadenylic acid also reversed cordycepin inhibition of virus-induced cytopathology of infected HeLa cells.
Production and Reactivity of Immune Sera Specific for HADEN Virus Polypeptide Antigens
Authors: Croft Garth F. , Hoggan M. David , Johnson F. Brent
Published: January 2020

Antisera were prepared against the three structural polypeptides of HADEN virus dissociated with sodium dodecyl sulfate. These immunological reagents were used in immunofluorescence tests to study the kinetics and location of polypeptide antigen appearance in infected cells. These sera did not neutralize virus infectivity, did not cross-react with adenovirus-associated virus-infected cells, and reacted in complement fixation tests with sodium dodecyl sulfate-dissociated virus, but not with complete virus antigen. The polypeptide antigens were heat labile, and all appeared in infected cells at least 2 h prior to whole-virus antigen.
Human Cytomegalovirus II. Lack of Relatedness to DNA of Herpes Simplex I and II, Epstein-Barr Virus, and Nonhuman Strains of Cytomegalovirus
Authors: Huang Eng-Shang , Pagano Joseph S.
Published: January 2020

The purified DNA of human cytomegalovirus, radiolabeled in vitro, was examined for homology to Epstein-Barr virus, herpes simplex type I and II, and simian and murine cytomegalovirus DNA by DNA-DNA reassociation kinetics analyses with the S1 enzyme differential digestion technique. Cross-matching of the DNAs showed no relatedness or less than 5% detectable homology.
Characterization of New Regulatory Mutants of Bacteriophage T4
Authors: Johnson James R. , Hall Dwight H.
Published: January 2020

Plating techniques which eliminate T4 plaque formation on
Escherichia coli
by folate analogue inhibition of dihydrofolate (FH
2
) reductase (EC 1.5.1.3) allowed the isolation of folate analogue-resistant (
far
) mutants of T4. One class of
far
mutants overproduces the phage-induced FH
2
reductase. Deoxycytidylate deaminase (EC 3.5.4.12), thymidine kinase (EC 2.7.1.21), and deoxycytidine triphosphatase (EC 3.6.1.12) are also overproduced by 20 min after infection at 37 C. The overproduction of FH
2
reductase by these
far
mutants is not affected by the absence of DNA synthesis. Other types of mutations that affect the synthesis of early enzymes cause overproduction in the absence of DNA synthesis of some of the above enzymes but not of FH
2
reductase. Therefore, overproducing
far
mutants apparently have mutations in previously undescribed genes controlling the expression of the T4 genome. Three of four mutants under study map near gene 56, and one maps near gene 52. All of these mutants show delays in DNA synthesis, phage production, and lysis and appear to show decreased levels of RNA synthesis based on the cumulative incorporation of uridine.
Origin and Direction of
Haemophilus
Bacteriophage HP1 DNA Replication
Authors: Stuy Johan H.
Published: January 2020

Rapidly growing
Haemophilus influenzae
strain Rd bacteria were infected with bacteriophage HP1 and DNA extracts prepared at various times thereafter. A number of phage genes scattered along the entire phage genome were quantitatively assayed by transformation. The kinetics of activity increases of these genes suggests that phage HP1 DNA replication begins at a fixed origin about one-quarter from the right end and that it proceeds to the left.
Fate of mRNA of L-Cells Infected with Mengovirus
Authors: Colby Diane S. , Finnerty Victoria , Lucas-Lenard Jean
Published: January 2020

Mengovirus infection of L-cells results in an inhibition of host protein synthesis which is detectable in vivo by a decreased rate of incorporation of radioactive amino acids into acid-insoluble material and by a concomitant reduction in polysome content. The inhibition of host protein synthesis occurs early in the infection cycle, at a time when there is little synthesis of viral proteins. In this paper the stability of polyadenylic acid [poly(A)]-containing mRNA of uninfected L-cells and cells infected with mengovirus is compared. Our results suggest that there is no increase in the rate of degradation of cellular mRNA upon virus infection. The continued integrity of host mRNA throughout infection was verified by acrylamide gel electrophoresis.
Host-Bacteriophage Interaction in
Agrobacterium tumefaciens
III. Phage-Coded Endolysins
Authors: Walls Patrica A. , Pootjes Christine F.
Published: January 2020

Endolysins were detected in a sensitive strain of
Agrobacterium tumefaciens
(B6) after infection with phage LV-1 and in the lysogen
A. tumefaciens
V-1 after induction with mitomycin C. A similar endolysin was found in mitomycin C-induced
A. tumefaciens
C-58, which apparently harbors a defective prophage.
Analysis of a Viral Agent Isolated from Multiple Sclerosis Brain Tissue: Characterization as a Parainfluenzavirus Type 1
Authors: Lewandowski L. J. , Lief F. S. , Verini M. A. , Pienkowski M. M. , ter Meulen V. , Koprowski H.
Published: January 2020

A virus originally isolated from cell cultures obtained by lysolecithin-induced fusion of human multiple sclerosis brain cells with CV-1 cells has been analyzed for its antigenic, RNA, and polypeptide compositions, and for selective biological properties. Our findings establish that this isolate, designated 6/94 virus, contains a 50
S
RNA genome and is, as yet, indistinguishable from Sendai virus in its antigenic and total polypeptide compositions. Despite these similarities, the 6/94 and Sendai viruses differ in certain phenotypic properties. 6/94 virus is markedly less cytocidal for chick fibroblasts, especially at 37 C and, after β-propiolactone inactivation, it possesses a greater capacity for cell fusion and a lower toxicity than does comparably treated Sendai virus. In addition, 6/94 virus shows greater hemolytic activity.
Location of the Origin of DNA Replication in Adenovirus Type 2
Authors: Horwitz Marshall S.
Published: January 2020

Utilizing the isolated left and right halves of both adenovirus type 2 and the nondefective adenovirus simian virus 40 hybrid (Ad2
+
ND
1
), studies were undertaken to find the site on the DNA molecules at which replication begins. The data are consistent with several models which include an initiation event at both ends and bidirectional growth.
Transfection of
Escherichia coli
Spheroplasts IV. Transfection of
rec
+
and
rec
−
Spheroplasts by Native, Denatured, and Renatured T5 Bacteriophage DNA After Repair of Single-Strand Breaks by Polynucleotide Ligase
Authors: Benzinger R. , Scheible P.
Published: January 2020

Transfection of
Escherichia coli
spheroplasts by native T5 phage DNA was not affected by treatment with polynucleotide ligase. Denatured T5 phage DNA infectivity, only 0.1% of the native DNA level, was increased slightly by polynucleotide ligase treatment. Renatured T5 phage DNA infectivity was also increased slightly by polynucleotide ligase treatment. To form an infective center with
rec
+
spheroplasts, 1.6 to 2.1 native T5 phage DNA molecules were required; however, 1.4 T5 phage DNA molecules were required to form an infective center with
recA
−
B
−
spheroplasts, and one molecule was sometimes sufficient for
rec B
−
spheroplasts. Polynucleotide ligase treatment of T5 phage DNA had no effect on these parameters. Thus, the single-strand interruptions of T5 phage DNA are probably not essential to the survival of the parental T5 phage DNA, and T5 phage DNA, especially the denatured form, is highly sensitive to some nucleases in
E. coli
spheroplasts.
Failure of an Influenza Virus to Initiate Infection in Enucleate BHK cells
Authors: Kelly D. C. , Avery R. J. , Dimmock N. J.
Published: January 2020

Studies employing indirect immunofluorescent staining, acrylamide gel electrophoresis of [
35
S]methionine-labeled cellular polypeptides, and RNA-RNA hybridization of [
3
H]uridine-labeled cellular RNA, failed to detect evidence of fowl plague virus infection of BHK cells enucleated with cytochalasin B, although virus-specific polypeptide and RNA synthesis was detected in nucleate BHK cells. The enucleate cells permitted the synthesis of Newcastle disease and vaccinia virus structural proteins. We conclude that influenza virus fails to initiate macromolecular synthesis in enucleate BHK cells, and the role of the nucleus in influenza virus replication is discussed.
Base Composition and Hybridization Studies of the Three Double-Stranded RNA Segments of Bacteriophage φ6
Authors: Van Etten J. L. , Vidaver A. K. , Koski R. K. , Burnett J. P.
Published: January 2020

The three double-stranded ribonucleic acid (dsRNA) segments of the bacteriophage φ6 were isolated and shown to have similar melting temperatures and base compositions. RNA:RNA hybridization experiments with the isolated segments eliminate the possibility that the two smaller dsRNA segments arise from a cleavage of the large dsRNA segment. The two smaller RNA segments reanneal rapidly even at low temperatures; in contrast, the large dsRNA reannealed only at higher temperatures. Evidence is also presented which suggests that the dsRNAs may contain a short single-stranded RNA tail.
Studies of Nondefective Adenovirus 2-Simian Virus 40 Hybrid Viruses Transformation of Hamster Kidney Cells by Adenovirus 2 and the Nondefective Hybrid Viruses
Authors: Lewis Andrew M. , Rabson Alan S. , Levine Arthur S.
Published: January 2020

Nonhybrid adenovirus 2 (Ad2) and five nondefective Ad2-simian virus 40 (SV40) hybrids (Ad2
+
ND
1
-Ad2
+
ND
5
) failed to produce tumors when injected into newborn hamsters. However, each of these agents transformed hamster kidney cells in vitro, and the transformed cell lines produced tumors when injected into suckling hamsters. Foci of cells transformed by the hybrids could not be distinguished from foci of cells transformed by nonhybrid Ad2. Histopathologically, tumors induced by the nondefective hybrid-transformed lines were of the adenovirus type with no areas of SV40-type fibrosarcoma. All of the cell lines studied contained Ad2 T antigen and Ad2 RNA. Only the B55HK
1
line contained the three early SV40 antigens, U, TSTA, and T. The ND
4
HK
1
line contained SV40 T and TSTA antigens (the latter antigen being detected only after 48 to 49 tissue culture passages) and SV40 RNA. The ND
2
HK
2
line contained SV40 RNA but no detectable SV40 antigens; the other hybrid-transformed lines contained no SV40 RNA. The transformation of hamster cells by the nondefective Ad2-SV40 hybrids seemed to be caused by the Ad2 genome and could not be attributed to the regions of the SV40 genome contained within the hybrids. Additionally, these results indicate that interactions between the genomes of the nondefective hybrid viruses and the hamster cells they transform are complex and could involve the site of integration, the size of the incorporated viral genome, the transcription or translation of the viral genome, or various combinations of these processes.
Cellular Replication and the Persistence of Inducible RNA Type C Viruses
Authors: Aaronson Stuart A. , Stephenson John R. , Greenberger Joel S.
Published: January 2020

Cells of mouse and rat origin contain endogenous type C viruses. There are intrinsic regulatory factors which restrict the ability of different classes of these inducible viruses to persist in cells after chemical activation. The cellular block to certain viruses is shown to be overcome under conditions in which the virus-activated cells are allowed continued exponential growth. These findings may help to explain the high frequency at which replicating type C viruses are detectable in naturally occurring tumors of some species.
Suppression of DNA Arrest Mutants in Bacteriophage T4
Authors: Kemper Börries , Jährig Lothar
Published: January 2020

A mutation in gene 49 of phage T4 was not able to restore DNA synthesis in a gene 46 mutant.
Serological Characterization of the Three Major Proteins of Vesicular Stomatitis Virus
Authors: Dietzschold Bernhard , Schneider Lothar G. , Cox James H.
Published: January 2020

The three major proteins of vesicular stomatitis virus-Indiana, glycoprotein (G), nucleoprotein (N), and membrane protein (M), were isolated and characterized by means of specific monocomponent antisera. G, N, and M proteins are distinct, nonrelated antigens with specific serological properties. The G protein is the only antigen inducing the formation of virus-neutralizing antibodies and was shown to confer immunity to mice. Specific complement-fixing and precipitating activity was demonstrated for each of the three antisera. The future use of isolated rhabdovirus components and of monospecific antisera is considered for therapeutic and diagnostic purposes as well as for virus strain differentiation and classification work.
Effect of Cycloheximide on RNA Metabolism Early in Productive Infection with Adenovirus 2
Authors: Craig Elizabeth A. , Raskas Heschel J.
Published: January 2020

The presence of cycloheximide during the early phase of adenovirus 2 replication causes an increase in the virus-specific content of newly synthesized mRNA. The total cytoplasmic RNA from control cultures labeled 2 to 5 h after infection hybridized to viral DNA 0.8%, whereas RNA synthesized in the presence of cycloheximide annealed 6%. Cytosine arabinoside, an inhibitor of DNA synthesis, did not affect the percent hybridization to viral DNA. Oligo(dT)-cellulose chromatography was used to purify the portion of cytoplasmic RNA containing poly(A). The poly(A)-containing RNA from cultures labeled in the presence of cycloheximide hybridized to viral DNA 32% as compared to 2.2% for RNA from control cultures. Hybridization-inhibition experiments between RNAs from control- and cycloheximide-treated cultures demonstrated that the cultures treated with cycloheximide did not have an increased content of viral RNA or a new class of viral RNA sequences. Therefore, the increased hybridization appears to be caused by a reduction in synthesis of cellular cytoplasmic mRNA. Nucleoplasmic RNAs lacking and containing poly(A) were annealed to viral DNA. For both classes, RNA from cultures treated with cycloheximide hybridized 5- to 10-fold more than RNA from control-infected cultures. Therefore, the increased hybridization of cytoplasmic RNA synthesized in the presence of cycloheximide is caused either by reduced transcription of the cellular genome or by greatly increased instability of cellular heterogeneous nuclear RNA.
Isolation and Characterization of RNA-Directed DNA Polymerase from a B-Type RNA Tumor Virus
Authors: Dion Arnold S. , Vaidya Akhil B. , Fout Garland S. , Moore Dan H.
Published: January 2020

RNA-directed DNA polymerase was isolated from milk-borne B-type murine mammary tumor virus of the RIII mouse strain. The several hundred-fold-purified enzyme sediments at 5.5 to 5.7
S
with an average molecular weight of approximately 100,000. The purified enzyme is completely template dependent and responds to RNA, DNA, and synthetic templates. Stability studies indicate differential lability dependent on the exogenous template used to monitor activity.
Detection of Baboon Type C Viral Sequences in Various Primate Tissues by Molecular Hybridization
Authors: Benveniste R. E. , Heinemann R. , Wilson G. L. , Callahan R. , Todaro G. J.
Published: January 2020

Nucleic acid sequences homologous to a single-stranded [
3
H]DNA transcript prepared from a baboon type C virus replicating in dog thymus cells can be readily detected in the cellular DNA of several Old World monkeys (baboon, patas, African green, and two species of macaques-rhesus and stumptail). These results demonstrate that primates other than the baboon also contain endogenous type C viral genes. With the hybridization conditions employed (S
1
nuclease, 65 C), no homologous sequences were detected in DNA from human or New World monkey tissues. Of various nonprimate tissues examined, only domestic cat cellular DNA was partially homologous to the baboon virus [
3
H]DNA transcript. In reciprocal experiments, [
3
H]DNA transcripts of RNAs from endogenous cat viruses (RD-114/CCC group) show a significant partial homology with cellular DNA from Old World primates (baboon, patas, and rhesus monkey). The partial homology between type-C-related information in the DNA of domestic cats and various Old World monkeys suggests the possibility of horizontal transmission between the progenitors of these animals at some point in evolution. No nucleic acid sequences homologous to [
3
H]DNA transcripts prepared from type C viruses isolated from tumor tissue of a woolly monkey and a gibbon ape could be detected in any primate tissue DNA examined; however, a partial nucleic acid homology was found between woolly monkey and gibbon ape type C viral [
3
H]DNA and normal mouse cellular DNA.
DNA-Dependent RNA Polymerase Activity Associated with Subviral Particles of Polyhedral Cytoplasmic Dexoyribovirus
Authors: Gaby Nancy S. , Kucera Louis S.
Published: January 2020

Polyhedral cytoplasmic deoxyribovirus virions contain a DNA-dependent RNA polymerase which catalyzes the incorporation of ribonucleotides into an acid-precipitable product. Treatment of virions with sodium deoxycholate and dithiothreitol resulted in the formation of subviral particles which could be separated from virions by rate zonal centrifugation in sucrose gradients. Subviral particles were RNA polymerase-positive and more active per unit mass of protein than virions. In vitro enzyme activity associated with subviral particles required addition of ribonucleotides, Mg
2+
, and exogenous denatured DNA template. Optimal enzyme activity occurred over a broad pH (7.2 to 8.8) and Mg
2+
concentration (2 to 10 μmol) range. The specific activity of the RNA polymerase was maximal at 37 C. Addition of DNase or actinomycin D to the reaction mixture reduced the incorporation of [
3
H]UMP into an acid-precipitable product. The product of the reaction was sensitive to degradation by RNase but not to DNase or Pronase. These data suggest that the enzyme copies DNA into RNA.
Phospholipase Activity in Bacteriophage-Infected
Escherichia coli
I. Demonstration of a T4 Bacteriophage-Associated phospholipase
Authors: Nelson E. T. , Buller C. S.
Published: January 2020

Phospholipase activity has been found to be associated with T4 phage and T4 ghost particles. The attachment of the phospholipase to the phage persists during purification through cesium chloride gradients and dialysis, indicating that it is firmly bound. The presence of the enzymatic activity on T4 ghosts suggests that it is not normally packaged within the head of the virus. The enzyme has specificity for phosphatidylglycerol and its activity is stimulated by 0.1% Triton X-100 and 20% methanol. It does not have a requirement for Ca
2+
and is inactivated at temperatures above 60 C. The association of the phospholipase with T4 phage grown in a phospholipase-deficient host and its absence on unsuppressed T4
amt
A3 suggests that it may be phage gene specific.
Characterization of Bromodeoxyuridine-Induced Endogenous Guinea Pig Virus
Authors: Murray Patrick R. , Nayak D. P.
Published: January 2020

An endogenous virus (GPV) was induced after 5-bromodeoxyuridine treatment of cultured guinea pig cells. Compared to Gross murine leukemia virus (G-MuLV) GPV has a reproducibly heterogenous density of about 1.16 to 1.18 g/ml. The virion-associated RNA is slightly larger than that in G-MuLV. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of dissociated GPV resolved five major structural proteins: I (molecular weight 70,000), II (molecular weight 36,000), III (molecular weight 24,000), IV (molecular weight 18,000), and V (molecular weight 16,000) which are similar to but distinct from G-MuLV proteins. Proteins I and II were demonstrated to be glycoproteins by incorporation of [
3
H]glucosamine. GPV and G-MuLV did not have any appreciable genetic homology or any common group-specific antigens when analyzed by immunodiffusion, radioimmunoassay, and indirect immunofluorescence. Morphogenesis of GPV also differed from that of a typical type C oncornavirus and proceeded via two pathways: (i) a majority of virus particles were formed in cytoplasmic vacuoles and were released after cellular disruption; and (ii) a minor population of particles were assembled in the cytoplasmic matrix and then migrated to the plasma membrane where they budded into the extracellular space. To date, GPV has been unable to initiate or maintain a productive replication in any cell line tested.
Comparative Studies on Functions of Human Adenovirus Type 12 and Its Low Oncogenic Mutant Virions
Authors: Ezoe Hisanori , Mak Stanley
Published: January 2020

Physical and biological properties of highly oncogenic human adenovirus type 12 were compared with a low oncogenic mutant (cyt mutant). Parental and cyt mutant virions had very similar density and DNA size. However, the parental strain virion preparations contained a much higher proportion of defective virions (capable of cell killing, but not able to induce T- or V-antigen) than cyt mutant stock. It was also found that cyt mutant had a reduced virus yield in several human cell lines compared with the parental strain.
Mechanism of Stimulation of Murine Type-C RNA Tumor Virus Production by Glucocorticoids: Post-Transcriptional Effects
Authors: Wu A. M. , Reitz M. S. , Paran M. , Gallo R. C.
Published: January 2020

We have previously shown that dexamethasone stimulates production of type-C virus from seemingly normal murine fibroblasts (BALB/3T3) and from transformed (Kirsten sarcoma-leukemia virus) nonproducing cells (BALB/K3T3) induced by 5-iododeoxyuridine. In this report, we further examine the mechanism of this effect by using BALB/K3T3 cells. Several observations suggest that this effect is post-transcriptional. The optimal stimulation by dexamethasone is obtained when dexamethasone is given 24 to 48 h after 5-iododeoxyuridine induction. Although this effect is late, time course experiments suggest that dexamethasone does not act to promote release of preformed virions. The stimulation by dexamethasone is blocked when cells are treated with cordycepin (3′-deoxyadenosine) during the first 24 h of induction, but not when cordycepin is added later. Conversely, interferon, which inhibits virus production, interferes with dexamethasone when it is added late or after removal of the steroid. The results of molecular hybridization experiments show that there is no detectable increase in Kirsten sarcoma-leukemia virus-specific RNA in dexamethasone-treated cells (with or without 5-iododeoxyuridine). The results of the time course studies, and the cordycepin, interferon, and hybridization experiments, suggest that the effect of dexamethasone on type-C virus production in this system is post-transcriptional.
Conditional Dependence of Fusion from Within and Other Cell Membrane Alterations by Newcastle Disease Virus
Authors: Gallaher William R. , Bratt Michael A.
Published: January 2020

Fusion from within (FFWI) by Newcastle disease virus occurs optimally in medium maintained at pH 8.2, whereas fusion from without is relatively insensitive to the pH of the medium in the range of 7.0 to 8.3. The pH-sensitive events in FFWI take place in the synthesis of the hypothetical fusion factor rather than in the response to it. pH pulse and pH shift experiments have localized the pH-sensitive events between 4 and 6.5 h postinfection (a period of synthesis of proteins required for FFWI), but before the fusion process. The pH sensitivity is not due to a pH-sensitive interference phenomenon. Virus production and the appearance of hemadsorbing cell surfaces are also pH sensitive, but for these functions the pH optima depend upon the virus strains tested. The independence of FFWI, hemadsorption, and virus production is discussed. Also discussed are the possible roles of virus-specific proteins in the fusion process.
Purification of Avian Myeloblastosis Virus DNA Polymerase by Affinity Chromatography on Polycytidylate-Agarose
Authors: Marcus Stuart L. , Modak Mukund J. , Cavalieri Liebe F.
Published: January 2020

Polycytidylic acid [poly(rC)] covalently linked to cyanogen bromide-activated agarose is an effective affinity matrix for the RNA-dependent DNA polymerase from avian myeloblastosis virus. Poly(rC)-agarose is capable of binding large quantities of avian myeloblastosis DNA polymerase, which is then eluted by using a linear KCl gradient of increasing concentration. The DNA polymerase isolated from crude, detergent-disrupted virions by a single pass through columns of poly(rC)-agarose appears nearly homogeneous (approximately 90% pure) as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Complete recovery of input enzymatic activity was obtained. Results suggest that polyribonucleotide columns may provide a high-yield, rapid method for the purification of oncornaviral DNA polymerase.