bluuebunny/crossref_metadata_2025 huggingface dataset:
Escherichia coli capsule bacteriophages. V. Lysozyme 29
Authors: Eichholtz H , Freund-Mölbert E , Stirm S
Published: January 2020

In addition to the spike-associated host capsule depolymerase, infection by Escherichia coli capsule bacteriophage no. 29 also induces the synthesis of a large bacteriolytic enzyme which has been purified to homogeneity. On incubation of isolated host murein sacculi with this enzyme, no amino groups but reducing sugar groups were liberated, and muraminitol, but no glucosaminitol, was found in the degraded sacculi after subsequent reduction with NaBH4. The bacteriolytic enzyme is thus another lysozyme (mucopeptide N-acetylmuramylhydrolase; EC 3.2.1.17). Electron optical visualization of negatively stained lysozyme specimens showed oblong particles of roughly 4.5 to 5.5 nm in diameter and 15 to 19 nm in length. Although the material tended to dissociate, a crude estimate of its molecular weight (270,000 plus or minus 30,000) could be obtained from these dimensions, from its sedimentation equilibrium, and from its behavior in gel chromatography. After disintegration of homogeneous lysozyme 29 by heating in solution with sodium dodecyl sulfate and dithiothreitol, polypeptides of one size only (about 46,000 dalton, probably six copies per molecule) were found in sodium dodecyl sulfate-polyacrylamide electrophoresis. The amino acid analysis of the enzyme accounted for more than 90% of its dry weight. One percent or less of the bacteriolytic activity in phage 29 lysates was found to be associated with the intact or disrupted virus particles, and a polypeptide of 46,000 daltons was not detected in the virions. These results strongly suggest that, in contrast to the host capsule depolymerase also induced by the same phage, and in spite of its comparatively large size, "lysozyme 29" does not constitute an integral part also of the homologous bacteriophage particles.
Serological studies with low-molecular-weight polypeptides from the Moloney strain of murine leukemia virus
Authors: Parks W P , Noon M C , Gilden R , Scolnick E M
Published: January 2020

Major virion low-molecular-weight polypeptides were isolated from the Moloney strain of murine leukemia virus (type C) by agarose chromatography in 6M guanidine hydrochloride and were shown to have molecular weights of 15,000 (p15), 12,000 (p12), and 10,000 (p10) by their elution volumes and by their relative mobilities in sodium dodecyl sulfate-polyacrylamide gels. Each polypeptide could be iodinated and employed in double antibody radioimmunoassay procedures. All three polypeptides demonstrated a high degree of type-specificity in serologic immunoprecipitation analysis and in corresponding competition immunoassays. The p15 was immunologically distinct from other viron polypeptides including p12 and p10; the p12 and p10 were highly related to each other but not to other virion polypeptides and were even more type-specific than the p15 in serologic tests. Competition immunoassays with p15 and p10 indicate that the Moloney strain of MuLV is only a distant relative of the Friend-Rauscher group. The combined use of the Kirsten and Moloney low-molecular-weight polypeptide immunoassays suggest that xenotropic viruses constitute yet another group(s) of murine leukemia virus with distinct type-specific antigens, further expanding an already heterogeneous group of mouse type C viruses.
Anatomy of herpes simplex virus DNA. II. Size, composition, and arrangement of inverted terminal repetitions
Authors: Wadsworth S , Jacob R J , Roizman B
Published: January 2020

Electron microscope studies on self-annealed intact single strands and on partially denatured molecules show that herpes simplex virus 1 DNA consists of two unequal regions, each bounded by inverted redundant sequences. Thus the region L (70 percent of the contour length of the DNA) separates the left terminal region a1b from its inverted repeat b'a'1, each of which comprises 6 percent of the DNA. The region S (9.4 percent of DNA) separates the right terminal region cas (4.3 percent of the DNA) from its inverted repeat a'sc'. The regions of the two termini which are inverted and repeated itnernally differ in topology. Thus, cas is guanine plus cytosine rich, whereas only the terminal 1 percent of the a1b region, designated as subregion a1, is guanine plus cytosine rich.
Transport in bacteriophage P22-infected Salmonella typhimurium
Authors: Khandekar P S , Burma D P , Taneja S K , Chakravorty M
Published: January 2020

There was rapid efflux of L-leucine, L-phenylalanine, and alpha-methyl-D-glucoside after infection of Salmonella typhimurium with the clear plaque mutant C1 of phage P22. The efflux was similar to that observed with cyanide or arsenate treatment except that there was partial recovery in the case of phage infection and almost complete recovery under the condition of lysogeny. There was no efflux after infection with the temperature-sensitive mutant ts16C1 at nonpermissive temperature. Superinfection of superinfection exclusion negative lysogen (sie A minus sie B minus) with C1 led to efflux, whereas the efflux was much less on superinfection of sie A+ Sie B+ lysogen. These results indicate that an effective injection process is enough to cause depression in the cellular transport processes.
Comparative studies on the structural phosphoproteins of mammalian type C viruses
Authors: Pal B K , McAllister R M , Gardner M B , Roy-Burman P
Published: January 2020

The major phosphoprotein common to woolly monkey sarcoma virus, gibbon ape lymphosarcoma virus, and type C viruses of the lower mammalian species (mouse, rat, cat), with the exception of the endogenous cat virus (RD-114), is the polypeptide of about 12,000 molecular weight. The protein-phosphate bond in this polypeptide of several viruses is of the phosphoserine variety excepting gibbon ape virus, which contains both phosphoserine and phosphothreonine. The primary phosphoprotein of RD-114 virus and the endogenous baboon type C virus, on the other hand, is the polypeptide of about 15,000 molecular weight which contains phosphothreonine as its phosphoamino acid. A second major phosphoprotein of molecular weight of 10,000 is detected only in viruses genetically related to rat species including those derived from the RPL cell line, from Sprague-Dawley rat embryo cells, and the Kirsten mouse sarcoma virus which was recovered from a mouse erythroblastosis virus after in vivo propagation through rat. These phosphorylated polypeptides of molecular weight 15,000, 12,000, or 10,000 are present in the virion structure in several different but nonrandom phosphorylated states.
Iodination of herpesvirus nucleic acids
Authors: Shaw J E , Huang E S , Pagano J S
Published: January 2020

A simple method is described for the iodination of herpes simplex virus (HSV) DNA. The procedure involved synthesis of 125-I-labeled 5-iodo-dCTP which was subsequently used as a precursor for the in vitro repair synthesis of HSV DNA. Synthesis of 5-iodo-dCTP and purification from oxidation and reduction reagents, buffer salts, unreacted dCTP and Na125-I was accomplished in a single chromatographic step. It was possible to prepare 125-I-labeled HSV DNA in vitro with specific activities exceeding 10-8 counts/min/mu-g. The DNA prepared by this method reassociated with DNA extracted from HSV-infected HEp-2 cells but not with HEp-2 cell DNA. Iodinated HSV DNA was susceptible to S-1-endonuclease digestion once denatured but was resistant to digestion in the native form. This method was used to synthesize 125-I-labeled ribo-CTP (5-iodo-CTP) which was used to prepare cytomegalovirus-specific complementary RNA. The method should be of value in the preparation of viral probes and for use in autoradiography of viral nucleic acids.
Simian virus 40 DNA replication, transcription, and antigen induction during infection with two adenovirus 2-SV40 hybrids that contain the entire SV40 genome
Authors: Siegel S E , Patch C T , Lewis A M , Levine A S
Published: January 2020

The Ad2++hey hybrid virus population produces simian virus 40 (SV40) efficiently during lytic infection, whereas Ad2++ley does not, although both hybrids contain a complete SV40 genome. In this report, we demonstrate the synthesis of nonhydrid SV40 DNA in Ad2++HEY-infected Vero cells, but only early SV40 RNA is transcribed efficiently in Ad2++LEY-infected cells. Ad2++HEY induces SV40 U, T, and V antigens during lytic infection of African green monkey kidney cells, whereas Ad2++LEY induces only SV40 U and T antigens. These variations in the behavior of Ad2++HEY and Ad2++LEY regarding expression of SV40 functions probably reflect differences in the rate of SV40 excision from the hybrid genomes.
Role of gene 59 of bacteriophage T4 in repair of UV-irradiated and alkylated DNA in vivo
Authors: Wu R , Wu J L , Yeh Y C
Published: January 2020

Nonsense mutants in gene 59 (amC5, amHL628) were used to study the role of this gene in the repair of UV-damaged and alkylated DNA of bacteriophage T4 in vivo. The higher sensitivity to UV irradiation and alkylation of gene 59 mutants after exposure to these agents was established by a comparison of the survival fractions with wild type. Zonal centrifugal analysis of both parental and nascent mutant intracellular DNA molecules after UV irradiation showed that immediately after exposure the size of single-stranded DNA fragments was the same as the wild-type intracellular DNA. However, the capability of rejoining fragmented intracellular DNA was greatly reduced in the mutant. In contrast, the wild-type-infected cells under the same condition resumed DNA replication and repaired its DNA to normal size. Methyl methanesulfonate induced more randomly fragmented intracellular DNA, when compared to UV irradiation. The rate of rejoining under these conditions as judged from their sedimentation profiles was also greatly reduced in mutant-infected cells. Further evidence is presented that UV repair is not a simple consequence of arrested DNA replication, which is a phenotype of the mutant when infected in a nonpermissive host, Escherichia coli B (su minus), but rather that the DNA repair function of gene 59 is independent of the replication function. These and other data presented indicate that a product(s) of gene 59 is essential for both repair of UV lesions and repair of alkylation damage of DNA in vivo. It is suggested that gene 59 may have two functions during viral development: DNA replication and replication repair of DNA molecules.
Role of gene 2 in bacteriophage T7 DNA synthesis
Authors: Center M S
Published: January 2020

Studies have been carried out to elucidate the in vivo function of gene 2 in T7 DNA synthesis. In gene 2-infected cells the rate of incorporation of (3-H)thymidine into acid-insoluble material is about 60% that of cells infected with T7 wild type. Gene 2 mutants do not however produce viable phage after infection of the nonpermissive host. In T7 wild type-infected cells, a major portion of the newly alkaline sucrose gradients. The concatemers serve as precursors for the formation of mature T7 DNA as demonstrated in pulse-chase experiments. In similar studies carried out with gene 2-infected cells, concatemers are not detected when the intracellular DNA is analyzed at several different times during the infection process. The DNA made during a gene 2 infection is present as duplex structures with a sedimentation rate close to mature T7 DNA.
Studies on the budding process of a temperature-sensitive mutant of murine leukemia virus with a scanning electron microscope
Authors: Wong P K , MacLeod R
Published: January 2020

The scanning electron microscope was used to study the budding process of the wild-type Moloney murine leukemia virus and one of its temperature-sensitive mutants, designated ts 3. A considerably larger number of budding particles was observed on TB cells infected with ts 3 at the nonpermissive temperature (39 C) than at the permissive temperature (34 C). No apparent difference was noted between the number of particles on ts 3-infected cells at (34 C) and wild-type-infected cells at 34 or 39 C. Virions were detected at the cell membrane of ts 3-infected cells at 39 C as early as 8 h postinfection. Virion density increased progressively up to 48 h after which no increase was observed. An average of 1,600 virus particles was observed at the cell surface at the peak of virus production. The distribution of these on the cell membrane appeared to be random. The maximum proportion of the cell surface occupied by the viral particles did not exceed 10%. After temperature shift from 39 to 34 C, approximately 90% of the particles had dissociated from the cell membrane within 1 h.
Synthesis of reovirus-specific polypeptides in cells pretreated with cycloheximide
Authors: Lau R Y , Van Alstyne D , Berckmans R , Graham A F
Published: January 2020

When L cells are infected with reovirus in the presence of cycloheximide neither virus-specific polypeptides nor viral double-stranded RNA are synthesized. There is some synthesis of viral single-stranded RNA, transcribed mainly from segments L1, M3, S3, and S4 of the 10 viral genomic segments, and in previous work this has been termed the early mRNA pattern. In an attempt to determine whether these early transcripts are functional mRNA's, the transcripts were allowed to accumulate for a period of 17.5 h at 31 C in cycloheximide-treated cells. The cycloheximide was removed and the cells were exposed for various periods to radioactive amino acids to label any virus-specific polypeptides that might be synthesized. An immunoprecipitation technique was used to separate the viral polypeptides from cellular extracts and this precipitate was then analyzed on sodium dodecyl sulfate-polyacrylamide gels. Within 30 min of cycloheximide removal, four major polypeptides (lambda2, mu0, sigma2a, and sigma3) and two minor polypeptides (lambda1 and mu2) were found. In infected cells without cycloheximide eight viral polypeptides (lambda1, lambda2, mu0, mu2, sigma1, sigma2, sigma2a, sigma3) were found at 17.5 h after infection and the same pattern was found between 3 to 4 h after removal of cycloheximide which had been present for 17.5 h after infection. The latter result shows that the cycloheximide inhibition is reversible and that the cells readily recovered and synthesized the normal complement of viral polypeptides. In one set of experiments cordycepin was added to infected cells immediately after the removal of cycloheximide at 17.5 h to inhibit the synthesis of new viral transcripts. During the succeeding 4 h in the presence of cordycepin, the pattern of protein synthesis was the same as that obtained during the 30 min after cycloheximide removal. It is concluded that the polypeptides formed right after removal of cycloheximide are the translation products of transcripts accumulated during cycloheximide treatment and, therefore, that these transcripts are functional viral mRNA's.
In vitro construction of different oligomeric forms of lambdadv DNA and studies of their transforming activities
Authors: Matsubara K , Takagi Y , Mukai T
Published: January 2020

Plasmid lambdadv1, which is in a dimeric form, was converted to a linear monomer duplex by the action of EcoRI restriction endonuclease that incises at a unique site in this plasmid genome. The resulting products were then joined by Escherichia coli DNA ligase to produce molecules with various oligomeric forms, and from these monomeric, dimeric, or trimeric circular molecules were purified. By transformation of cells with these DNAs, clones were obtained that carried lambdadv1 in a monomeric or dimeric form. The former type of clones have not been generated in vivo, except for one in a different host strain, and carriers of timeric or tetrameric lambdadv1's have not been obtained so far. It was observed that a considerable fraction of these oligomeric circular DNAs were converted to lower oligomers (e.g., from trimer to dimer) during transformation. The characteristics of the monomeric lambdadv1 carriers obtained were compared with those of dimeric lambdadv1 carriers. The stabilities of the plasmids of the two forms were the same. However, the monomeric plasmid carriers were less tolerant to lambdavir phage infection and perpetuated about 30% less plasmid genomes in monomer units. Furthermore, dimeric plasmid carriers appeared spontaneously and accumulated in cultures of the monomeric lambdadv1 carriers.
Virion-associated transcriptase activity of influenza recombinant and mutant strains
Authors: Bean W J , Simpson R W
Published: January 2020

A comparative study of the in vitro reaction kinetics of the virion RNA polymerase of influenza A strains WS and WSN was conducted to establish phenotypic differences for enzyme activity that might be exchanged as genetic markers among recombinants of these viruses. Characteristically, the RNA polymerase activity of WS virus showed an initial rate of synthesis about two- to threefold higher than that of WSN when assayed at 32 C. The two strains were also distinguishable by comparing the transcription rates of each strain at 32 and 37 C. The initial rate of WS was invariably higher at 37 than at 32 C, whereas the opposite was found with WSN. When a series of recombinants obtained from mixed infections with the WS and WSN viruses were examined for virion transcriptase activity, it was found that the two polymerase related markers behaved as properties which segregated independently of each other and of additional nonselective markers that were scored. Seven temperature-sensitive mutants of WSN virus representing distinct recombination-complementation groups were found to show a diminished transcriptase activity as compared to wild-type virus, and one of these clones (ts 24) was largely deficient for this function. None of these mutants appeared to possess a heat-liable virion polymerase.
Genetic studies of coliphage P1. I. Mapping by use of prophage deletions
Authors: Walker D H , Walker J T
Published: January 2020

One hundred and ten amber mutants of coliphage P1 were isolated and localized into groups with respect to the existing genetic map by use of nonpermissive Escherichia coli K-12 strains lysogenic for P1 with deletions. These lysogens contain one of three types of deletion prophages: P1cry and its derivatives, P1dlacs, and P1dpros. Fourteen such lysogens were tested for their ability to rescue the amber mutants which were then assigned to one of nine deletion segments of the P1 genome defined by the termini of the various prophage deletions. The relationship of the nine deletion segments with the published P1 map is described, two new segments having been added. The deletions of the 14 prophages overlapped sufficiently to indicate that the P1 genetic prophage map should be represented in circular form, which is consistent with the fact that P1 is normally a circular plasmid in the prophage state. The distribution of mutants into deletion segments is nonrandom for at least one segment. In addition, the deletion termini of the 14 defective prophages coincided in five out of nine regions separating the nine deletion segments. Various possible explanations are discussed for the nonrandom recurrence of these deletion termini, including the evidence of hot spots of recombination.
Proteins of bacteriophage phi6
Authors: Sinclair J F , Tzagoloff A , Levine D , Mindich L
Published: January 2020

We investigated the protein composition of the lipid-containing bacteriophage phi 6. We also studied the synthesis of phage-specific proteins in the host bacterium Pseudomonas phaseolicola HB10Y. The virion was found to contain 10 proteins of the following molecular weights: P1, 93,000; P2, 88,000; P3, 84,000; P4, 36,800; P5, 24,000; P6, 21,000; P7, 19,900; P8, 10,500; P9, 8,700; and P10, less than 6,000. Proteins P3, P9, and P10 were completely extracted from the virion with 1% Triton X-100. Protein P6 was partially extracted. Proteins P8 and P9 were purified by column chromatography. The amino acid composition of P9 was determined and was found to lack methionine. Labeling of viral proteins with [35S]methionine in infected cells indicated that proteins P5, P9, P10, and P11 lacked methionine. Treatment of host cells with UV light before infection allowed the synthesis of P1, P2, P4, and P7; however, the extent of viral protein synthesis fell off exponentially with increasing delay time between irradiation and infection. Treatment of host cells with rifampin during infection allowed preferential synthesis of viral proteins, but the extent of synthesis also fell off exponentially with increasing delay time between the addition of rifampin and the addition of radioactive amino acids. All of the virion proteins were seen in gels prepared from rifampin-treated infected cells. In addition, two proteins, P11 and P12, were observed; their molecular weights were 25,200 and 20,100, respectively. Proteins P1, P2, P4, and P7 were synthesized early, whereas the rest began to increase at 45 min post-infection.
Attachment of a Long-Tailed
Rhizobium
Bacteriophage to the Pili of Its Host
Authors: Lotz Wolfgang , Pfister Herbert
Published: January 2020

Bacterial strain 16-12 was isolated from the root nodules of lupines and was found to be mitomycin C-inducible for the production of a bacteriophage (“16-12-1”) with a long noncontractile tail. The phage was found to attach with a fork-like terminal tail structure to the pili of strain 16-12. In addition, it was also found adsorbed to the bacterial cell poles. It is suggested that phage 16-12-1 may be pilus dependent.
Base sequence differences between the RNA components of Harvey sarcoma virus
Authors: Maisel J , Scolnick E M , Duesberg P
Published: January 2020

The 50 to 70S RNA of the Harvey sarcoma-Moloney leukemia virus (MLV) complex consists of 30 to 40S RNA subunits of two different size classes and contains sequences homologous to Moloney mouse leukemia virus and to information contained in a C-type rat virus, termed NRK virus. We have isolated by preparative gel electrophoresis the large (component 1) and the small (component 2) 30 to 40S RNA species from the Harvey sarcoma-MLV complex. Harvey RNA component 1 was completely complementary to DNA transcribed from MLV RNA and showed no homology to DNA transcribed from NRK virus when annealed under conditions of DNA excess. Harvey RNA component 2 was about 65% complementary to MLV DNA and about 33% complementary to NRK virus DNA. Approximately 60 to 80% of the MLV-specific sequences in RNA component 2 is either a distinct molecular species or is part of a hydrid molecular including NRK virus- and MLV-specific sequences. The rest of the MLV sequences in component 2 could be accounted for by degraded component 1 co-purifying with component 2. The possible role of these sequences in the ability of the virus to transform cells is discussed.
Intragenic Complementation by Gene 42 Amber Mutations of Bacteriophage T4
Authors: Holmes George E.
Published: January 2020

Phage T4 amber mutants defective in gene 42 (dCMP hydroxymethylase) were shown by in vivo and in vitro experiments to participate in both positive and negative intragenic complementation. This argues that incomplete polypeptide chains can participate in subunit interaction.
Termination sites for adenovirus type 2 DNA replication
Authors: Tolun A , Pettersson U
Published: January 2020

Termination sites for replication of adenovirus type 2 DNA have been demonstrated at both ends of the viral chromosome by the procedure of Danna and Nathans (1972). Single-stranded DNA from replicating intermediates was also characterized by hybridization with separated strands of viral DNA. The results indicate that both strands are exposed during replication.
Murine xenotropic type C viruses I. Distribution and further characterization of the virus in NZB mice
Authors: Levy J A , Kazan P , Varnier O , Kleiman H
Published: January 2020

The xenotropic mouse type C virus, originally detected in cultured embryo cells from New Zealand Black (NZB) mice, has been recovered from over 50 adult NZB animals and 15 NZB embryos. Its presence is best detected by measuring its ability to rescue a murine sarcoma virus (MSV) genome from a non-virus-producing MSV-transformed rat cell. The virus can serve as a helper for replication of MSV. It has a distinct type-specific coat and is a prototype for a third serotype of mouse type C viruses, NZB. The xenotropic virus may have an evolutionary role since it has a wide host range, including the ability to infect avian cells. It is produced spontaneously by all cells cultivated from NZB tissues and accounts for the high concentration of viral antigens associated with NZB tissues. The extent of virus production is similar in both male and female mice. All cell clones established from embryos also produce the virus. A variability in the intracellular regulation of virus replication is suggested since tissue cells from the same animal differ quantitatively in their ability to produce xenotropic viruses. Since enhanced spontaneous virus production is associated with cells from NZB mice, the virus may play a role in the autoimmune disease of this mouse strain.
Identification of early adenovirus type 2 RNA species transcribed from the left-hand end of the genome
Authors: Craig E A , McGrogan M , Mulder C , Raskas H J
Published: January 2020

Unique fragments of adenovirus type 2 DNA generated by cleavage with endonuclease R-Eco RI or endonuclease R-Hsu I (Hin dIII) were used to map cytoplasmic viral RNAs transcribed early in productive infection. Radioactive early viral RNA was first fractionated by polyacrylamide gel electrophoresis. Eluted viral RNAs were then tested for hybrid formation with DNA fragments. The Eco RI DNA fragment (Eco RI-A) which contains the left-hand 58% of the genome hybridized 13S and 11S RNAs. More detailed mapping of these RNAs was achieved by hybridization to the seven Hsu I fragments of Eco RI-A. The early RNA annealed only to Hsu I-G and C, two fragments which comprise the extreme left-hand 17% of the genome. Viral RNA migrating as 13S and 11S annealed to Hsu I-G, and 13S RNA annealed to Hsu I-C. A 13S RNA is transcribed from Eco RI-A late in infection (18 h). Hybridization-inhibition studies with Eco RI-A DNA, early cytoplasmic RNA, and 3H-labeled 13S late RNA demonstrated that this RNA synthesized at late times is an early RNA species which continues to be synthesized in large amounts at 18 h. This 13S RNA synthesized at 18 h hybridized to Hsu I-C but not to Hsu I-G DNA. These results establish that the 13S RNAs transcribed from Hsu I-G and C at early times must be different species.
Virus-induced proteins in pseudorabies-infected cells. II. Proteins of the virion and nucleocapsid
Authors: Stevely W S
Published: January 2020

Analysis of purified naked and enveloped nucleocapsids of pseudorabies virus with high-resolution techniques has allowed a reassessment of their protein composition. Enveloped particles are shown to contain at least 20 proteins whose molecular weights are in the range 20,000 to 230,000. Naked nucleocapsids contain one major and seven minor proteins in the molecular weight range 20,000 to 155,000. Phosphorylation of at least one virion protein is shown to take place in vivo. These results demonstrate that pseudorabies virus is similar in its protein complement to other herpesviruses which have recently been examined.
Infective and noninfective hemagglutinating particles of Newcastle disease virus: biological and chemical characterization
Authors: LaMontagne J R , Schiller J G , Thacore H R , Feingold D S , Youngner J S
Published: January 2020

Newcastle disease virus (Herts strain), grown in embryonated eggs or in a line of bovine kidney cells, was purified and then separated by sucrose density gradient centrifugation into infectious (IH) and noninfectious hemagglutinating (NIH) particles. These particles were morphologically similar, although the average size of IH was twice that of NIH particles. The activity of hemagglutinin per milligram of virus protein was two- to threefold higher in NIH particles than in IH particles, whereas the specific activity of neuraminidase did not differ in the two particle types. This was consistent with the observed particle size difference. The distribution of the major proteins in IH and NIH particles from egg-grown virus, determined by polyacrylamide gel electrophoresis (PAGE), was significantly different. In IH particles the molar ratio of protein 1 (74,000 daltons) to proteins 2 and 3 (56,000 daltons): protein 6 (41,000 daltons) was 1.0:2.5:2.5; in NIH particles the ratio was 1.0:0.6:1.0. When Newcastle disease virus was grown in bovine kidney cells, the molar ratio of proteins in IH particles resembled that of of egg-grown virus. However, in NIH particles from bovine kidney cells, only protein bands corresponding to protein 1 and proteins 2-3 were present and their molar ratio was 1.0:0.6. Protein 6 was marginally detectable in these particles. Analysis of the proteins in [3H]isoleucine- and [14C]glucosamine-labeled virus showed proteins 1 and 2 (glycoproteins) present in the ratio of 1.0:0.5; protein 3, the nucleoprotein, was not detected. These results are compatible with previous findings by others that NIH particles are deficient in RNA and nucleoprotein antigen, and suggest that formation of discrete particles of Newcastle disease virus by budding requires at most minimal amounts of proteins 3 or 6. The fatty acid composition of egg-grown IH and NIH particles was not significantly different and resembled that of normal allantoic fluid.
Role of carbohydrate in determining the immunochemical properties of the major glycoprotein (gp71) of Friend murine leukemia virus
Authors: Bolognesi D P , Collins J J , Leis J P , Moennig V , Schäfer W , Atkinson P H
Published: January 2020

Treatment of Friend leukemia virus gp71 with protease-free glycosidase enzymes results in removal of the major portion of the carbohydrate without affecting the amount of protein present. The digested material migrates as protein of about 60,000 to 65,000 molecular weight on sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Analyses of the serological properties of gp71 after enzyme treatment indicated that the type, group, and interspecies determinants were not destroyed. In contrast, treatment with proteolytic enzymes led to the complete destruction of the gp71 molecule, including the total elimination of its serological reactivity as measured by direct and competition radioimmunoassay and by a serum cytotoxicity assay. We conclude that the carbohydrate portion of gp71 is not of major significance in defining the antigenic determinants of this viral glycoprotein.
Regulation of macromolecular synthesis in reovirus-infected L-929 cells I. Effect of L-histidinol
Authors: Warrington R C , Wratten N
Published: January 2020

The histidine analogue L-histidinol, reported by Vaughan and Hansen (1973) to establish a potent, readily reversible inhibition of eukaryotic protein synthesis in vivo, was used to investigate the regulation of macromolecular synthesis in reovirus-infected L-929 cells. The addition of L-histidinol to normal L cells led to a total inhibition of protein synthesis. The inhibition appeared to be a consequence neither of isotope dilution resulting from elevated endogenous amino acids nor of an inability of treated cells to accumulate exogenous amino acids. Addition of L-histidine to histidinol-arrested cells resulted in a complete recovery of protein synthesis. Similarly, protein synthesis in reovirus-infected L cells examined 17 h postinfection (31 C) was totally inhibited by histidinol treatment and was readily reversed by the addition of histidine. Reovirus-infected cells treated with histidinol had an essentially unaltered capacity to synthesize reovirus single-stranded RNA relative to unperturbed cultures but a diminishing ability to maintain genome RNA synthesis. Addition of L-histidine to arrested cultures led to a complete recovery of genome RNA synthesis. The L-histidinol-mediated arrest of protein synthesis was both very effective and easily reversed, suggesting the general applicability of this novel inhibitor to investigations of regulation of macromolecular synthesis in both normal and virus-infected eukaryotic cells.
Evidence for an “Early Early” Vaccinia Virus-Induced Protein Which Causes a Density Change of Infected L-M Cells
Authors: Ball Frederick R. , Medzon Edward L.
Published: January 2020

The density decrease of vaccinia virus-infected L-M cells observed in a Ficoll density gradient by 2 h postinfection was found to be dependent on RNA synthesis and protein synthesis but independent of DNA synthesis. Using low multiplicities of infection, the required RNA and protein species appeared to be synthesized before parental viral DNA became sensitive to DNase, i.e., while the bulk of input virus was still at the core stage of uncoating. To date only thymidine kinase and a vaccinia virus-specific cell surface antigen (as well as the putative uncoating protein) have been shown to be “early early” proteins, i.e., synthesized while parental viral DNA is still enclosed within the core. Both heat-and UV-inactivated virus failed to cause the cell density decrease. The need for a functioning viral genome implies that the required early early RNA and protein species are virus specific and not cell specific. Thus the protein leading to the density decrease of L-M cells, induced very early after infection with vaccinia virus, represents one of the first bits of viral genetic information expressed after infection. Since antibody-neutralized virus is still capable of causing the phenomenon of cell density decrease, the basis of neutralization of vaccinia virus by specific antibody must be other than by inhibiting early early transcription and/or translation.
Comparison of RNA Polymerase Associated With Newcastle Disease Virus and a Temperature-Sensitive Mutant of Newcastle Disease Virus Isolated from Persistently Infected L Cells
Authors: Stanwick Trevor L. , Hallum J. V.
Published: January 2020

An in vitro comparison was made of the RNA polymerase activity associated with Newcastle disease virus (NDVo) and three clones of the temperature-sensitive mutant (NDVpi) isolated from persistently infected L cells. Less polymerase activity was associated with the NDVpi clones. Also, compared to NDVo, an increase in incubation temperature from 32 to 37 or 42 C resulted in a marked decrease in polymerase activity for the temperature-sensitive mutants which coincided with their inability to replicate at 42 C.
Virus-Dependent Glycosylation
Authors: Sefton Bartholomew M.
Published: January 2020

The oligosaccharides of the membrane glycoproteins of Sindbis virus, vesicular stomatitis virus, and Rous sarcoma virus were compared on the basis of apparent size and sugar composition. It appears that each virus acquires a different set of oligosaccharides during growth in a single type of cell.
Endonucleases and simian virus 40 virions: origin of a virion-associated endonuclease
Authors: Dooley D C , Ryzlak M T , Ozer H L
Published: January 2020

The origin and role of the endonuclease activity associated with purified virions of simian virus 40, previously described by this and other laboratories, have been further investigated. We found that the enzymatic activity from virions of temperature-sensitive (ts) mutants is not more heat labile than that from wild-type virions. This result was obtained for a variety of ts mutants, including three of the tsA class, and in experiments in which the enzyme was tested in both the presence and absence of viral particles. Comparison of the viron enzyme with endonucleases prepared from either serum or nuclei of uninfected cells reveals a similarity between the viron and serum enzymes based on chromatographic behavior and relative activity with different cations. Virus particles prepared free of this endonuclease were still infectious. We were unsuccessful in uncovering endonuclease in such preparations upon disruption. These data emphasize the necessity for caution in interpreting the role of particle-associated enzymes.
Sonic fragility of the head-tail bond of bacteriophage P22
Authors: Ruddel M , Israel V
Published: January 2020

The binding of tail parts to the head of phage P22 is normally irreversible, but after adsorption to host cells sonication releases many of the tail parts intact. This release is dependent on the power of sonication, but is independent of the length of sonication from 2 to 32 s. This phenomenon has been used to show that the upper limit of the number of P22 particles that can bind to a cell is no lower than 700.
Proposed structure of two defective viral DNA oligomers produced in 3T3 cells transformed by the ts-a mutant of polyoma virus
Authors: Vogt M , Bacheler L T , Boice L
Published: January 2020

The various oligomeric viral DNA species produced at 32 C by two related syblines of ts-a-transformed mouse 3T3 cells were characterized. Results from the analysis of the cleavage products observed after digestion with restriction endonucleases from Haemophilus parainfluenzae, Escherichia coli RI, and Haemophilus suis are consistent with the assumption that in both sublines, the major oligomeric component is a dimer from which a segment of different length is deleted. The major oligomeric (27S) component in subline 1 was estimated to be 1.77 times the size of the viral monomer, and the major (25.5S) component in subline 15 was estimated to be 1.54 times the size of the viral monomer. These size estimates were confirmed by electron micrograph measurements. The larger oligomers produced by both sublines were found to be multiples of the major oligomeric component of each subline.
Formation of an infectious virus-antibody complex with Rous sarcoma virus and antibodies directed against the major virus glycoprotein
Authors: Schlesinger M J
Published: January 2020

Preparations of Rous sarcoma virus (RSV) can form an infectious viral-antibody complex with antibodies raised against the major glycoprotein, gp85, isolated from avian myeloblastosis virus and Prague-RSV subgroup C. Binding of anti-gp85 antibodies to RSV can be demonstrated by the inhibition of focus-forming activity after addition of goat anti-rabbit immunoglobulin and by a shift in density of virions treated with anti-gp85 serum. Group- rather than subgroup- specific regions of viral gp85 appear to be the site of binding for infectious complex.
Biochemical, biophysical, and biological properties of densonucleosis virus. I. Structural proteins
Authors: Tijssen P , van den Hurk J , Kurstak E
Published: January 2020

The polypeptide composition of highly purified densonucleosis virus was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The viral proteins showed a different behavior in sodium dodecyl sulfate-gels in comparison with the marker proteins. Therefore, the molecular weights were estimated by analyzing the retardation of the electrophoretic mobility of these proteins in gels with increasing polyacrylamide concentrations. Four structural proteins with molecular weights of 49,000, 58,500, 69,000, and 98,000 were found, ant they were designated p49, p59, p69, and p98, respectively. There are several indications that p98 is a dimer of p49. The relative quantity of the structural proteins in a virion suggests that at least p49 (accounting for +/-70% of total protein mass) is a capsid protein and that there will be 12 capsomers per virion.
Red system of bacteriophage lambda complements the growth of a bacteriophage T1 gene 4 mutant
Authors: Christensen J R
Published: January 2020

The ability of phage lambda to complement the growth of T1am23, a T1 gene 4 mutant with a DNA arrest phenotype, has been shown to require both lambda Red functions, redX and redB. lambdagam function, however, is not required. Therefore, the lambda Red function can substitute for T1 gene 4 function. However, T1+ does not substitute for lambda Red in allowing lambda to grow in a polA host.
Late Events in T4 Bacteriophage Production. II. Giant Bacteriophages Contain Concatemers Generated by Recombination
Authors: Kozinski Andrzej W. , Kosturko Linda D.
Published: January 2020

Analysis of “giant” phage, which package concatenated DNA into their capsids, shows that they are predominantly heterozygous. The results are compatible with the hypothesis that concatemers are generated by recombination.
Protein synthesis in bacteriophage ghost-infected cells
Authors: Takeishi K , Kaji A
Published: January 2020

Escherichia coli B infected with T4 phage ghosts at 10 mM Mg2+ regains its protein synthesizing activity upon addition of ATP, GTP, and their generator to approximately 2% of the intact exponentially growing cells. In contrast to amino acid incorporation by intact cells, this system is sensitive to EDTA or low Mg2+. On the other hand, this system, differing from the regular cell-free system, does not respond to addition of soluble protein and ribonuclease. The ghost-infected cells were able to synthesize beta-galactosidase upon addition of the inducer isopropyl thiogalactoside. The initial rate of the induction was 2.6% of intact cells. For this induction, the addition of cyclic AMP, amino acids, ATP, GTP, UTP, CTP, and their generator was necessary. The induction of beta-galactosidase in these ghost-infected cells was very sensitive to the addition of EDTA, CaCl2, sulfhydryl blocking reagent, rifampin and chloramphenicol but insensitive to DNA synthesis inhibitors such as nalidixic acid and DNase.
Inhibition of Epstein-Barr virus DNA synthesis and late gene expression by phosphonoacetic acid
Authors: Summers W C , Klein G
Published: January 2020

Growth of lymphoblastoid cells (B95-8, Raji) is not inhibited by the presence of 0.4 mM phosphonoacetic acid. The synthesis of Epstein-Barr virus (EBV) in the producer line B95-8 is completely inhibited, as shown by the total inhibition of viral capsid antigen synthesis. Early viral antigens are made normally in the presence of phosphonoacetic acid, but EBV DNA synthesis is blocked in cells entering the productive cycle. Nonproducer cells in the population replicate the resident EBV DNA by a mechanism that is resistant to phosphonoacetic acid. These results are consistant with the hypotheses that EBV DNA is replicated by two mechanisms, one in the noninduced cell and a different mechanism in the producer cell, and that prior replication of EBV DNA, probably by the second mode, is a prerequisite for late gene expression.
Hin D restriction mapping of upaired regions in simian virus 40 superhelical DNA I: considerations regarding structure-function relationships
Authors: Chen M , Lebowitz J , Salzman N P
Published: January 2020

Superhelical simian virus 40 (SV40) DNA I was reacted with N-cyclohexyl-N'-beta-(4-methylmorpholinium)ethylcarbodiimide (CMC), and the location of CMC sites was mapped using the Hin D restriction endonuclease. The use of 14C-labeled CMC allows a quantitative analysis of the binding to the respective Hin D restriction endonuclease fragments. The percentage of reactivity was 6.54% for fragment A, 3.87% for fragment B, and 2.74% for fragment G. No CMC radioactivity was detected in other fragments. This reactivity is in agreement with the evaluation of binding by buoyant density measurements. The above fragments also contain the sites susceptible to S1 endonuclease action. This adds further support to the view that superhelical DNA can contain regions of localized interrupted secondary structure which may be capable of forming intrastrand hairpin structures if sequence relationships are favorable. The possible structure-function relationships for this model are discussed with the emphasis on transcription.
Role of the bacteriophage P22 tail in the early stages of infection
Authors: Israel V
Published: January 2020

The initial binding of phage P22 to its host, Salmonella typhimurium, is dependent in a linear fashion on the number of tail parts per phage head. (The normal head has six.) There is also a later step which depends on tail parts. This step must occur some time after hydrolysis of the O antigen has been initiated and before ejection of phage DNA from the head is complete. This step causes PFU to depend on approximately the third power of the number of tail parts per head.
Transcriptase activity and genome composition of defective influenza virus
Authors: Bean W J , Simpson R W
Published: January 2020

Eight genome RNA segments are present in both normal and von Magnustype influenza virus preparations and all species are transcribed by the virion-associated polymerase. Although the RNA polymerase activity and the amount of the three largest RNA segments are reduced in defective influenza virus preparations, these reductions do not appear to be great enough to account for the much greater loss of infectivity.
Lysogenization of Escherichia coli by bacteriophage Lambda: complementary activity of the host's DNA polymerase I and ligase and bacteriophage replication proteins Q and P
Authors: Ray U , Sakalka A
Published: January 2020

When bacteriophage lambda DNA replication is blocked by mutation in phage genes O or P, the efficiency of lysogenization drops to a very low value unless high multiplicities of infecting phage are used. Our results show that even at high multiplicity, lambda O or P mutants cannot efficiently lysogenize some hosts that are defective in either DNA polymerase I or DNA ligase. Covalent closure of infecting DNA molecules, a preliminary step for insertion according to Campbell's model and an obvious candidate for this lysogenization defect, appears to occur normally under our conditions. In addition, prophage excision as measured by the frequency of curing O- and P- lysogens seemed normal when tested in the poll- strain. These results suggest that the Escherichia coli enzymes DNA polymerase I and ligase, and phage proteins O and P, are able to provide some complementary activity whose function is required specifically for prophage integration.
Effects of 2-deoxyglucose, glucosamine, and mannose on cell fusion and the glycoproteins of herpes simplex virus
Authors: Knowles R W , Person S
Published: January 2020

2-Deoxyglucose and glucosamine were found to inhibit cell fusion caused by a syncytial mutant of herpes simplex virus and to inhibit the glycosylation of viral glycoproteins in the infected cells. The inhibition of fusion and the inhibition of glycosylation caused by 2-deoxyglucose were substantially prevented when mannose was also present during infection. When glycosylation was inhibited, three new bands were found in major glycoprotein region on sodium dodecyl sulfate-polyacrylamide gels. These bands may be precursors to the normal glycoproteins. The correlation between fusion and glycosylation in the presence of 2-deoxyglucose, glucosamine, and mannose suggests that the cells cannot fuse if their glycoproteins have a considerably reduced carbohydrate content.
DNA-Protein Complex in Circular DNA from
Bacillus
Bacteriophage GA-1
Authors: Arnberg Annika C. , Arwert Fré
Published: January 2020

DNA prepared from bacteriophage GA-1 contains circular DNA molecules, which are converted to linear molecules by treatment with trypsin.
Mechanism of premature polypetide termination in a mouse ascites cell-free system programmed by encephalomyocarditis viral RNA
Authors: Hunt L A
Published: January 2020

The premature termination and release of encephalomyocarditis viral RNA-programmed polypeptides were analyzed in a cell-free system from mouse ascites tumor cells. The KCL concentration affects the size distribution of products but not the extent of polypeptide release. The same major products (60,000 to 140,000 molecular weight) are found in both the soluble and particulate fractions. The majority of released polypeptides are free protein, whereas the ribosome-bound product is mostly in the form of peptidyl-tRNA.