| transformation of cells by rous sarcoma virus: cytoplasmic vacuolization. | chick embryo cells transformed by the bryan "high titer" strain of rous sarcoma virus (rsv-bh) are heavily vacuolated. a variety of microscopic techniques have been used demonstrating that the vacuoles are cytoplasmic, bounded by membrane, and are composed largely of water. proteins, lipids, glycoproteins, glycolipids, glycosaminoglycans, glycogen, and nucleic acids were undetectable in the vacuoles. physiological requirements for development of the vacuoles, and reversal of vacuolization, were ... | 1976 | 54359 |
| a comparison of four methods used to concentrate rous sarcoma virus from tissue culture fluids. | three methods of pelleting, pelleting followed by pronase treatment, polyethylene glycol (peg)-pronase, and diaflo ultrafiltration (diafiltration) were used to concentrate rsv(rav-1) from tissue culture fluids. sucrose-gradient fractions containing virus preparations which had been concentrated by diafiltration or pelleting were heavily contaminated with amorphous debris. this debris was not present in similar, gradient-purified preparations that had been concentrated by the peg-pronase or pelle ... | 1976 | 63539 |
| extensive in vitro transcription of rous sarcoma virus rna by avian myeloblastosis virus dna polymerase and concurrent activation of the associated rnase h. | conditions are described that promote the efficient reverse transcription of most of rous sarcoma virus (rsv) rna sequences by avian myeloblastosis virus dna polymerase in vitro. a detailed analysis of the reverse transcription reaction was carried out using two procedures: in situ analysis of the rna sequences transcribed and dna-rna annealing studies. under optimal conditions, after 1 h of reaction, practically all rsv rna sequences were transcribed with a frequency varying from 30 to 90%. the ... | 1977 | 70539 |
| endogenous dna polymerase of a transformation-defective rous sarcoma virus: characterization and comparison with the enzyme of the non-defective parent. | an rna-directed dna polymerase associated with transformation-defective (td) segregant of rous sarcoma virus (rsv) has been characterized. the enzyme required both a monovalent and a divalent cation, a sulfhydryl reducing agent, and all four deoxyribonucleoside triphosphates for the expression of maximal activity. sensitivity of the endogenous rna-directed dna polymerase activity to a low concentration of pancreatic rnase indicated that the enzyme utilized the td virus endogenous rna as template ... | 1976 | 62591 |
| comparison of dna in the core component from schmidt-ruppin rsv transforming virus and non-transforming virus. | | 1976 | 61031 |
| in vitro transcription of 70s rna by the rna-directed dna polymerase of rouse sarcoma virus: lack of influence of rnase h. | the influence of rous sarcoma virus (rsv)-associated rnase h on the in vitro synthesis of dna by the rsv rna-directed dna polymerase was determined under conditions whereby rnase h activity was selectively inhibited with naf. not only were we unable to detect any effect on the size, structure, or genetic complixity of the dna product synthesized in the absence of rnase h activity, but the displacement of dna from the 70s rna:dna hybrid structures was also unaffected. the suitability of 70s rna:d ... | 1975 | 54443 |
| detection of antibody to bovine syncytial virus and respiratory syncytial virus in bovine fetal serum. | batches of commercial fetal bovine serum, described by the suppliers as antibody-free, all contained antibody to bovine syncytial virus (bsv) when tested by indirect immunofluorescence. antibody to bovine respiratory syncytial virus (rsv) was not detected in these sera. twenty-four percent of individual fetal bovine sera contained antibody to bsv, and 14% contained antibody to rsv when tested by indirect immunofluorescence. bsv antibody titers in fetal sera from dams with high bsv antibody level ... | 1978 | 100508 |
| the longitudinal approach to the pathogenesis of respiratory disease. | longitudinal observations were made of a well-defined population of children at a day care center in an investigation of the pathogenesis of infections due to respiratory syncytial virus (rsv) and mycoplasma pneumoniae. a single rsv infection induced a modest but significant degree of resistance to further rsv infection in these children. age and immunity seemed to interact to decrease the intensity of the clinical expression of illness associated with rsv infection. infants and young children h ... | 1979 | 121783 |
| clinically useful method for the isolation of respiratory syncytial virus. | a simple method for the isolation of respiratory syncytial virus (rsv) is reported; it is relatively rapid and results in a high frequency of recovery of virus. a nasal secretion specimen with high titers of virus is inoculated at the bedside onto susceptible cell lines to avoid loss of viral infectivity due to liability of the virus. during an outbreak of rsv, viral specimens were obtained by this method from all young children admitted to the hospital with lower respiratory tract disease. rsv ... | 1975 | 162921 |
| rna-directed dna polymerase activity of reticuloendotheliosis virus: characterization of the endogenous and exogenous reactions. | reticuloendotheliosis virus (rev) contains an endogenously instructed, rna-directed dna polymerase activity. both the endogenous and exogenous dna polymerase activities exhibited up to 10-fold greater activity at the optimum concentration of manganous ion (0.025 mm for exogenous; 0.25 mm for endogenous) than at any concentration of magnesium ion. antiserum to the dna polymerase of an rev group virus (spleen necrosis virus) inhibited both endogenous and exogenous dna polymerase activity of rev, w ... | 1975 | 51935 |
| transcription of the rous sarcoma virus genome in vitro and in vivo. | rna-directed dna synthesis by detergent-disrupted virions of rous sarcoma virus (rsv) initiates by the covalent attachment of pda to the 3'-terminal ra of a 4s rna hydrogen-bonded to the 70s rna template. this 4s "primer" has structural features of trna and can be aminoacylated with methionine. synthesis and integration of provirus dna can be monitored in both permissive (duck) and nonpermissive (mouse) cells acutely infected with rsv. the results of these studies, as well as data obtained with ... | 1975 | 51635 |
| an outbreak of severe pneumonia due to respiratory syncytial virus in isolated arctic populations. | a rapidly developing outbreak of pneumonia in young infants was documented in two isolated artic populations in may 1972. these were studied virologically, serologically and clinically. in addition to the two stricken communities, one apparently unaffected with serious clinical illness and a fourth, in which are located the major hospital and airport in the eastern arctic, were also studied. one hundred and twenty-four patients were studied serologically and 81 respiratory and other specimens we ... | 1975 | 163574 |
| characterization of rna polymerases from rous sarcoma virus-induced mouse ascites sarcoma cells. | rna polymerase was extracted from the schmidt-ruppin strain of rous sarcoma virus (sr-rsv)-induced c3h/he mouse ascites sarcoma cells (sr-c3h). rna polymerase was separated into rna polymerases i and ii by deae-sephadex chromatography. rna polymerase i was separated into ia and ib fractions by phospho-cellulose chromatography. in sr-c3h cells rna polymerase ib was the main component of rna polymerase i. at 0.05--0.1 m ammonium sulphate rna polymerase i transcribed native dna most actively, and r ... | 1979 | 38635 |
| potential of attenuated respiratory syncytial virus vaccine for infants and children. | respiratory syncytial virus (rsv) disease is a major cause of death and hospitalization in infancy and a frequent cause of morbidity throughout childhood. serum antibody does not protect as is evident from the study of natural disease and use of killed vaccines. local antibody responses occur in natural illness. possibly serum antibody in the absence of local antibody plays a part in illness. we have studied local and serum antibody response to potential attenuated vaccines: a 26 degrees c adapt ... | 1975 | 165119 |
| cytoplasmic vacuoles of rous virus transformed cells are organelles involved in cation uptake. | cytoplasmic vacuoles induced during transformation of cells by bryan strain rous sarcoma virus (rsv-bh) have been studied using the cationic dye, neutral red(nr). both the rate of uptake and the accumulation of nr are greater in rsv-bh transformed cells than non-transformed cells however, uptake was greater in vacuolated than in non-vacuolated cells, whether or not they were transformed. the nr was incorporated into pre-existing vacuoles in the absence of cytoplasmic staining, suggesting the exi ... | 1978 | 24677 |
| coordinate control of collagen synthesis and cell growth in chick embryo fibroblasts and the effect of viral transformation on collagen synthesis. | using collagenase digestion as an assay for collagen in partially synchronized secondary cultures of chick embryo fibroblasts, we find that the rate of collagen synthesis remains at a constant fraction of overall protein synthesis (5%) regardless of the growth rate of the cells even when the rate of protein synthesis is accelerated 5-fold by adding serum and altering the ph of the culture medium. however, in cells oncogenically transformed by rous sarcoma virus, the relative rate of collagen syn ... | 1977 | 19483 |
| effect of regression of rous sarcoma tumors upon egg production in an inbred line of white leghorns. | reserach was conducted to determine whether development and subsequent regression of a rous sarcoma virus (rsv) induced wing-web tumor influenced egg production. fifty-seven six-week old pullet chicks of inbred line 6 of the united states department of agriculture, regional poultry research laboratory, east lansing, michigan, were inoculated subcutaneously in the left wing-web with 0.1 ml. of a 10-minus 3 dilution of a pseudotype of bryan high titer rsv designated bh-rsv (rav-1). thirty chicks ... | 1975 | 166364 |
| an avian oncovirus mutant (se 21q1b) deficient in genomic rna: biological and biochemical characterization. | we have isolated a nonconditional mutant of pr-rsv-e with unique properties. this virus (se 21q1b) is shed from a continuously growing culture of transformed quail cells. 21q1b virions are unable to transform or replicate in other quail or chicken cells after exogenous infection, despite the fact that the viral particles contain normal envelope glycoproteins, internal structural proteins and rna-dependent dna polymerase. the lack of infectivity of 21q1b virions is a consequence of the failure to ... | 1978 | 83199 |
| inactivation and inhibition of rous sarcoma virus by copper-binding ligands: thiosemicarbazones, 8-hydroxyquinolines, and isonicotinic acid hydrazide. | we have shown that three types of copper-binding ligands, thiosemicarbazones, 8-hydroxyquinolines, and isonicotinic acid hydrazide and their copper complexes, inactivate the transforming ability of rsv and inhibit its rna-dependent dna polymerases. three other compounds, 2-pyridine thiosemicarbazone, 1-formyl isoquinoline thiosemicarbazone, and diphenyl thiocarbazone inhibit transformation by rsv intracellularly. most but not all of these compounds bind to nucleic acids in the presence of copper ... | 1977 | 81642 |
| [detection of common antigenic determinants in the envelopes of mammalian type d (mason--pfizer) and type c virions by using the virion precipitation reaction]. | immune sera to mason-pfizer virus (m-pmv) are capable of precipitating type c viruses of mice (nih-mulv, g-mulv, and to a lower degree r-mulv), cats (felv, rd-114), and monkeys (ssv-1, galv, bev). the immune sera to rd-114, bev, ssv-1 and galv viruses can precipitate m-pmv virions. the adsorption analysis suggests that cross-reactions between m-pmv, rd-114, nih-mulv, and g-mulv viruses depend on common virus-specific antigenic determinants in the envelopes of the virions. the relationship betwe ... | 1978 | 80888 |
| effect of isonicotinic acid hydrazide-copper complex on rous sarcoma virus and its genome rna. | the copper complex of the antituberculous drug, insonicotinic acid hydrazide (inh), inhibits the rna-dependent dna polymerase of rous sarcoma virus and inactivates its ability to malignantly transform chick embryo cells. the inh-copper complex binds to the 70s genome rna of rous sarcoma virus (rsv), which may account for its ability to inhibit the rna-dependent dna polymerase. the complex binds rna more effectively than dna in contrast to m-ibt-copper complexes, which bind both types of nucleic ... | 1978 | 80234 |
| tumor-specific and tumor-associated membrane antigens of rous sarcoma virus transformed hamster fibroblasts. | hamster fibroblasts transformed by an env- strain of rous sarcoma virus (rsv) express at their surface tumor-associated antigens of unknown origin and a tumor-specific antigen (vcsa) which is not expressed by hamster fibroblasts transformed by unrelated dna or rna oncogenic viruses. this antigen was detectable by rabbit antibodies and a complement-dependent 51cr-release cytotoxicity assay and is common to rsv-transformed cells of different animal species. by comparing the anti-vcsa serum which a ... | 1978 | 79559 |
| decreased levels of collagen mrna in rous sarcoma virus-transformed chick embryo fibroblasts. | we have found that double-stranded cdna synthesized in extended reactions by avian myeloblastosis virus reverse transcriptase is suitable substrate for a variety of restriction endonucleases. experiments in which rabbit reticulocyte mrna was reverse-transcribed and restricted to generate beta-globin-specifihe nucleotide sequence of beta-globin mrna. this method has been applied to study collagen mrna synthesis in normal and rous sarcoma virus (rsv)-transformed chick embryo fibroblasts. character ... | 1978 | 78927 |
| genetic recombination among temperature-sensitive mutnats of rous sarcoma virus. | genetic recombination of rsv has been studied, using ts mutations in both initiation and maintenance of transformation as markers. the progeny of a single cycle of mixed infection appears to contain no recombinants, but yields heterozygous particles or viral clumps. on subsequent cycles of infection some of these heterozygotes/clumps persist, but they also segregate recombinant viruses. some of the markers in these recombinants show evidence of linkage and thus probably recombine by intramolecul ... | 1975 | 169044 |
| anti-tumor virus activity of copper-binding drugs. | several, structurally different, copper-binding ligands can inhibit the rna-dependent dna polymerase of rous sarcoma virus (rsv) and can inactivate the ability of the virus to malignantly transform chick embryo cells. these ligands include the anti-microbial agents, thiosemicarbazones, 8-hydroxyquinolines, isonicotinic acid hydrazide, and others. many of these compounds bind to dna and rna in the presence of copper, which may play a role in their anti-viral activity. however, not all agents acti ... | 1977 | 75679 |
| virological and immunological characteristics of tumors induced in adult rats by rous sarcoma. | forty primary tumors of wistar rats and first seven passages of tumors of august rats were investigated by different virological and immunological methods. the tumors were induced in adult rats by schmidt--ruppin strain of rous sarcoma. based on the virus-cell interaction, the tumors were divided into four groups. the first group of tumors of wistar rats (2 out of 40) contained mature rsv and viral antigens could be detected by means of the fa test, while the rats had virus neutralizing antibodi ... | 1977 | 73143 |
| tumour-associated transplantation antigen in sera of rats with large rsv-induced sarcomas. | a factor inhibiting tumour growth in syngeneic hosts was found in the sera of inbred lewis rats carrying rous sarcoma virus-induced tumour (rsl). the findings presented here suggest that the serum factor is a tumour-associated transplantation antigen (tata) shed from the neoplasm into the circulation. all the tumour bearers' sera tested with rsl cells were negative in indirect membrane immunofluorescence;however, on passive transfer into syngeneic rats, they protected the animals against the gro ... | 1975 | 170216 |
| cellular and humoral anti-tumor immune responsiveness in chickens bearing tumors induced by avian sarcoma virus. | a systematic comparison was undertaken of the respective abilities of normal chicken embryo fibroblast (cef) cells, rous sarcoma virus (rsv)- transformed cef cells, avian rous sarcoma (rs) tumor cells and murine rs cells to serve as targets and antigen donors in various assays for the detection of cellular and humoral anti-tumor immunity in chickens bearing tumors induced by rous sarcoma virus. as measured by a cytotoxicity procedure, avian and murine rs cells were more susceptible to the killin ... | 1977 | 68016 |
| presence of chicken cell surface antigen on rous virus activated in heterokaryons of transformed non-permissive hamster cells and chicken cells. | incubation with antiserum to chick embryo (ce) cells, in the presence of complement, inactivates rous sarcoma virus (rsv) produced by heterokaryons formed by non-permissive rsv-transformed hamster cells and ce cells as well as rsv produced by heterokaryons is observed following incubation with antiserum to the transformed hamster cells, plus complement. hence, the envelope of rsv activated in heterokaryons, as that of rsv produced by ce cells, must contain a surface antigen of the ce cell, and t ... | 1975 | 170372 |
| new procedure for the direct analysis of in vitro reverse transcription of rous sarcoma virus rna. | based on the observation that in vitro transcription of rous sarcoma virus (rsv) rna by avian myeloblastosis virus dna polymerase renders the rna progressively more sensitive to escherichia coli rnase h digestion, a new procedure for the in situ analysis of this process has been developed. in vitro transcription products of 32p-labeled rsv rna are first treated with rnase h, the resistant fraction is then digested to completion with rnase t1, and the oligonucleotides are analyzed by a fingerprin ... | 1977 | 67218 |
| tumor growth and antibodies after rsv-challenge in normal chickens and in chickens congenitally infected with avian leukosis virus. | normal chickens and chickens congenitally infected with an avian leukosis virus (alv) of antigenic subgroup a were challenged with strains of rous sarcoma virus (rsv) of two different antigenic subgroups (b and c) and tumor induction and growth as well as humoral antibody to viral envelope antigen (vea) and tumor-specific surface antigen (tssa) were measured. there was no effect of congenital alv infection on rsv tumor incidence or latent period but the growth rate and size of the tumors were mu ... | 1977 | 67140 |
| [differential expression of relevant rous sarcoma tumor antigens in cultured cells]. | chickens bearing tumours induced by rous sarcoma virus (rsv) are able to mount a cellular immune response against antigens associated with these neoplasms. cultured rous sarcoma (rs) cells, derived from the wings of chickens bearing tumors induced by rsv, were consistently more susceptible in cytotoxicity assays to killing by the splenic lymphocytes of rs-bearing chickens than were chicken embryo fibroblast (cef) cells which had been transformed in vitro by rsv. in contrast, extracts (3m kci-der ... | 1977 | 66892 |
| interactions between endogenous baboon type-c virus and oncogenic viruses. i. syncytium induction and development of infectivity assay. | cells releasing the endogenous baboon virus (bv) can interact with human kc cells containing the rous sarcoma virus (rsv) genome, resulting in cell fusion and syncytium formation. this interaction has been utilized in the development of a sensitive infectivity assay for bv. the titration pattern is of a one-hit type, demonstrating a linear relationship between virus concentration and number of syncytial plaques obtained in the kc co-cultivation assay. endpoint titration comparisons indicate that ... | 1975 | 171228 |
| [oncornavirus activation and accumulation in cell cultures under the influence of hormones]. | sex hormones (testosterone, estradiol) and thyroxine would activate irregularly the production of the specific group antigen (gs-antigen) of avian ribodesoxyviruses in the culture of "normal" chick embryonal cells (cec, phenotype c/o, gs-). the mentioned hormones as well as hydrocortisone and insulin would not prevent the rous sarcoma virus (rsv) infecting of cec, render no essential action on the accumulation of rsv in the infected cec culture, and failed to activate the formation of mature rsv ... | 1979 | 85368 |
| the expression of avian gs antigen in mammalian rous sarcoma virus-transformed cells after treatment with 5-iododeoxyuridine and dexamethasone. | the content of avian gs antigen in rsv-transformed rat cells lw13-rsk1 and lw13-rsk4 showed a transient increase after treatment with 5-iododeoxyuridine. higher levels of gs antigen were found when treated cells were cultivated in the presence of dexamethasone. in no case was the production of rsv found in treated rsv-transformed rat cell lines when, in addition, xc cells were tested. | 1975 | 172376 |
| characteristics of infection by rsv. iii. duration of the latent period in unsynchronized chick embryo fibroblasts. | the duration of the latent period of rsv was studied in unsynchronized chicken cells using two methods. first, rav1-producing cells were infected with schmidt-ruppin strain of rous sarcoma virus (sr-rsv;subgroup d), and new virions of sr-rsv (subgroup a) produced after phenotypic mixing with rav1 were neutralized with an antiserum to rav1. secondly, uninfected chicken cells were infected with sr-rsv (d) in the presence of either arabionsylcytosine, actinomycin d or cycloheximide, to inhibit the ... | 1975 | 172471 |
| development of allergy in children. i. association with virus infections. | children born into allergic families, with two allergic parents, are at high risk of developing allergy within the first 5 years of life. in order to observe possible external factors in the sensitization process, a prospective study of 13 such children was done, in which serial clinical and immunologic observations were made at 3- to 6-month intervals over a period of 1 to 4 yr. eleven of these children are now clinically allergic; 5 have asthma. immunologic evidence for allergic sensitization ... | 1979 | 85648 |
| recombination between a temperature-sensitive mutant and a deletion mutant of rous sarcoma virus. | cells doubly infected with two mutants of the schmidt-ruppin strain of rous sarcoma virus (rsv), ts68, which is temperature sensitive for cell transformation (srcts), and a deletion mutant, n8, which is deficient in the envelope glycoprotein (env-), produced a recombinant which carried the defects of both parents. the frequency of formation of such a recombinant was exceptionally high and made up 45 to 55% of the progeny carrying the srcts marker. by contrast, the reciprocal recombinant, which i ... | 1976 | 60496 |
| induction of syncytia by the bovine c-type leukemia virus. | bovine buffy coat cells infected with the bovine leukemia virus (blv) induce syncytia formation in human diploid embryonic lung cells as well as in monolayer cell cultures of bovine, simian, ovine, bat, and caprine origin, but not in mouse fibroblast cells, normall rat kidney cells, or rsv-transformed rat cells. syncytia were not observed in diploid embryonic lung cells inoculated with bovine buffy coat cells free of blv. the syncytia-induction effect is associated with the synthesis of complete ... | 1976 | 175949 |
| properties and kinetics of development of rous sarcoma virus-infected cells evidenced by methylene blue staining. | three different kinds of areas of infected cells corresponding to different focus formation stages can be evidenced by methylene blue (mb) staining in cultures of chick embryo (ce) fibroblasts infected at low multiplicity with the temperature-sensitive (ts) mutant of rous sarcoma virus (rsv), fu19, which transforms these fibroblasts at 37 degrees but not at 41 degrees. these are: (a) areas of mb-stainable cells with transformed phenotype (stp areas=foci); (b) areas of mb-stainable cells with nor ... | 1975 | 57944 |
| formation of an infectious virus-antibody complex with rous sarcoma virus and antibodies directed against the major virus glycoprotein. | 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 appe ... | 1976 | 56458 |
| [study of the population composition of the rous sarcoma virus carr-zilber strain]. | the population composition of the carr-zilber high titer (ht) strain of rous sarcoma virus (c-z-rsv) was analysed with regard to 2 features: the capacity to impart oncogenicity for syngeneic recipients to infected but untransformed cultures of mouse embryo tissue (met), and oncogenicity for mice. with regard to these features the c-z-rsv (ht) strain was found to be heterogenic and to consist of particles of at least two types: non-oncogenic for mice and incapable of causing early malignization o ... | 1975 | 176824 |
| [transfer of the genetic information of oncornaviruses by means of tumor cell dna]. | the infection process was reproduced in the culture of chick embryonal cells by means of: a) dna isolated from chick rous sarcoma (carr-zilber strain); b) dna from blood cells of chicks with myeloblastosis (strain a); c) dna from rous virus malignified (prague strain) rat cells (xc). antigenic properties of the virus, transfected with dna from chick rous sarcoma, would differ from the original parental strain (carr-zilber rsv), that evidences the possibility of a partial transfer of genetic info ... | 1976 | 178103 |
| in vivo host immune to a tumor-specific transplantation antigen induced by rous sarcoma virus. | we examined the host immune response to a tumor-specific transplantation antigen (tsta) induced by rous sarcoma virus (rsv) in vivo. in contrast to previous in vitro studies, the present investigation demonstrated in vivo host immunity of the tsta 10-55 days after tumor inoculation. immunity to the tsta appeared specific, since the homologous rsv tumor was rejected. whereas the heterologous tumor grew progressively. no generalized suppression of cell-mediated or hymoral immunity was shown, becau ... | 1976 | 56445 |
| immunization of rous sarcoma virus-inoculated marmosets with bcg and transformed allogeneic cells. | the effects of specific immunotherapy with allogeneic cells transformed by schmidt-ruppin rous sarcoma virus (sr-rsv), of treatment with bcg, and of surgery on the growth of sr-rsv-induced sarcomas in white-lipped marmosets were studied. tumor incidence, tumor progression, and survival did not differ between control and treated animals. animals immunized with bcg developed lymphocyte reactivity to tuberculin, which remained until the animals died. bcg was isolated from the spleen of one tumor-be ... | 1975 | 163312 |
| characterization of an early cytotoxicity-inducing factor in sera of japanese quails after inoculation with rous sarcoma virus. | by pre-treatment with serum of normal spleen cells used in the microcytotoxicity assay, a humoral factor which induces cytotoxic activity in normal spleen cells was demonstrated in about 40% of sera of japanese quails as early as 3 days after inoculation with rous sarcoma virus (rsv). this cytotoxicity-inducing activity was not present either in the igm or the igg fraction obtained by sephadex gel filtration. in sera of quails with experimentally induced agammaglobulinemia, the cytotoxicity-indu ... | 1976 | 179959 |
| respiratory syncytial virus infections in infants: quantitation and duration of shedding. | infants hospitalized with respiratory syncytial virus infection were studied to delineate the quantitative shedding patterns and duration of shedding of rsv. nasal wash specimens collected daily from 19 infants contained a mean maximal titer of 4.34 log10 50% tissue culture infective doses per milliliter. on admission, the mean titer was 4.14 log10 tcid50, with no consistent decline until after day 6. the mean duration of shedding for 23 patients until they were virus negative was 6.7 days with ... | 1976 | 180274 |
| molecular weight of rna subunits of rous sarcoma virus determined by electron microscopy. | secondary cultures of chicken embryo fibroblasts were infected with the schmidt ruppin strain of rous sarcoma virus (rsv). five days after infection, the medium was replaced at 2-h intervals with phosphate-free eagle medium containing 50 muci of [32p]orthophosphate per ml. virus was collected by centrifugation, and the rna was extracted and denatured with dimethyl sulfoxide, and the 33s subunit rna was isolated by sucrose gradient centrifugation. the molecular weight of the rsv subunit rna was d ... | 1975 | 163340 |
| detection and characterization of rna tumor virus-specific dna in cells. | rna tumor virus-specific dna in cells can be detected by its capacity to 1) alter the reassociation kinetics of labeled double-stranded product of viral rna-directed dna polymerase; 2) anneal single-stranded dna (cdna) synthesized by viral polymerase; or 3) hybridize labeled viral 70s (genomic) rna. duplexes formed with these procedures can be analyzed for fidelity of base pairing, and the integration of viral dna into the host genome can be established with a simple but stringent technique. we ... | 1975 | 51630 |
| respiratory syncytial virus and heart disease. a report of two cases. | two patients had cardiac disease and serological evidence for respiratory syncytial virus (rsv) infection. the first patient had myocarditis and complete atrioventricular heart block with repeated syncopal episodes two weeks following infection. the second patient had alcoholic cardiomyopathy and worsening congestive heart failure associated with rsv infection. the significance of rsv infection in these two patients may bear a significant relationship to sudden infant death syndrome, chronic car ... | 1976 | 181602 |
| further evidence for the existence of a viral envelope protein defect in the bryan high-titer strain of rous sarcoma virus. | electron microscopy observations of purified bryan high-titer rous sarcoma virus (bh rsv) using the freeze-drying technique showed that progeny made in the absence of a helper virus lacked visible surface projections or spikes. phenotypic mixing experiments employing bh rsv and a thermolabile mutant of vesicular stomatitis virus, tl 17, yielded no evidence of pseudotype formation. since tl 17 is known to be defective for an envelope glycoprotein, the lack of successful phenotypic mixing with bh ... | 1975 | 168409 |
| phenotypic mixing test to detect and assay avian leukosis viruses. | a phenotypic mixing (pm) test for detecting and assaying avian leukosis viruses (alv) of the a, b, c, and d subgroups is described. an alv and rous sarcoma virus rsv-0) are phenotypically mixed by co-cultivating on c/o (cells susceptible to all subgroups of alv) cells for a certain period. then the rsv with the new virus property is assayed on c/e cells (cells resistant to infection with subgroup e leukosis/sarcoma viruses). the test is relatively simple and rapid, and its results are unequivoca ... | 1975 | 168850 |
| 2-deoxy-d-glucose uptake by chick embryo cells: a biochemical indicator of genetic susceptibility to rna tumour viruses. | the enhanced glucose uptake by chick embryo cells as early as 72 h after infection with rous sarcoma virus (rsv) was confirmed in this study to be an early indicator of cellular transformation. the glucose uptake of c/e brl cells infected by various doses of bs-rsv of subgroup a showed that the relationship between the log-dose of virus and log-uptake was linear (slope, b1 = 1.30 +/- 0.14) when the ratio of the number of infectious virus particles to the number of cells in the culture was above ... | 1976 | 182917 |
| infectious viral dna in rous sarcoma virus-transformed nonproducer and producer animal cells. | nonproducer and producer rsv-transformed cells and producer nontransforming virus-infected cells harbor viral dna specifying the respective avian tumor virus. in nonproducer rous sarcoma cells, the residing viral dna is linear, double-stranded and covalently linked to the chromosomal dna. both double-stranded and single-stranded forms of rsv dna transfect chicken cells. the progeny virus is indistinguishable from the dna parent with respect to the morphological, biological and antigenic properti ... | 1975 | 169003 |
| neutral protease activity of rous sarcoma (rsv) transformed chick embryo fibroblasts. | the proteolytic activities of normal, schmidt-ruppin rous sarcoma virus (sr-rsv) transformed, and infected (rav) chick embryo fibroblasts (cef) have been measured by a highly sensitive technique using 3h-acetylated haemoglobin as a substrate. when all 3 types of cef cells were maintained in serumless media, no differences were detected in the amount of ph 3-4 protease activity released into the media over a 24-h period, and only negligible amounts of ph 7-6 proteolytic activity were found. when ... | 1976 | 184099 |
| further studies in genetic resistance of fowl to rsv(rav o): evidence for interaction between independently segregating tumour virus b and tumour virus e genes. | the segregation of resistant and susceptible phenotypes in response to infection by rsv(rav 2), rsv(rav 50) and rsv(rav 0), of avian rna tumour virus subgroups b, d and e, respectively, was analysed in several test-crosses using chickens from the rprl line 7-2, hprs-synthetic line e and the reaseheath line c. the results were fully consistent with out view reported previously that the genes at the tve and tvb loci segregate independently and recombine under the mendelian second law of independen ... | 1976 | 184240 |
| infectious dna from cells infected with rous sarcoma virus, reticuloendotheliosis virus or rous-associated virus-o. | we have described an efficient and quantitative assay for infectious dna of the avian ribodeoxyviruses and have applied this method to study the possible existence of infectious viral dnas in uninfected cells. infectious dna from cells infected with rsv or rev consisted of a single unit of dna with a specific infectivity of 10(-5)-10(-6). the minimum molecular weight of rsv dna required for infection of chicken cells was about 6 million, while the minimum molecular weight of infectious rev dna w ... | 1975 | 169004 |
| characteristics of a human cell line successively transformed by rous sarcoma virus and simian virus 40. | human enbryo cells were successively transformed by the schmidt-ruppin strain of rous sarcoma virus (sr-rsv) and simian virus 40 (sv40) in vitro, and the double transformant hue 13 rs was established. from this cell line the two clonal cell lines rsa and rsb were isolated. in both, presence of sv40 t antigens was demonstrated by the fluorescent antibody technique, and the presence of rsv genomes was verified in one rsb clone by focus formation after fusion with chick embryo cells. growth of thes ... | 1976 | 186619 |
| 35s a and b rna subunits of avian rna tumor virus strains cloned and passaged in chick and duck cells. | the rna of transforming and nontransforming avian rna tumor viruses was heat denatured and examined for its 35s subunit composition by polyacrylamide gel electrophoresis (gel slicing and/or autoradiography). the rna of virus strains capable of transforming chick embryo fibroblasts in vitro always contained a subunits: the rna of pr-rsv of subgroups a, b or c was composed only of a subunits, even after prolonged passage in chick cells, whereas the rna of sr-rsv-a, sr-rsv-b, sr-rsv-d(h) and b77 al ... | 1975 | 169040 |
| plaque assay of avian sarcoma viruses using casein. | the caseinolytic activity of several strains of rous sarcoma virus (rsv), conditional and nonconditional mutants of rsv, and nontransforming avian leukosis viruses was investigated. only those viruses capable of transforming chick fibroblasts in vitro induced lysis of casein incorporated into an agar overlay. lysis produced distinct clear areas in the turbid casein-agar gel which allowed a quantitative "plaque" assay of cell transformation. casein plaque formation could not be separated from mor ... | 1975 | 169393 |
| rous sarcoma regression in chickens resistant or susceptible to marek's disease. | in 4 experiments, strains of chickens relatively susceptible (s-strain, p-line) or resistant (n-line, pdrc) to marek's disease (md) were challenged with rous sarcoma virus (rsv) at 6-8 weeks old. rsv tumors occurred in 94-100% of the birds in each strain, but the number with tumors that regressed during the 40-46-day experiment varied from 7% (s-strain) to 91% (pdrc). the n-line and p-line birds, derived from a random-bred flock with selection only for susceptibility or resistance to md, regress ... | 1975 | 169801 |
| appearance of c-type virus-like particles after co-cultivation of a human tumor-cell line with rat (xc) cells. | a serially progagated cell line (l104) was established by co-cultivation of alung adenocarcinoma (l-1) from a patient with concurrent chronic lymphocytic leukemia and xc, a non-producer rat line, known to carry the rous sarcoma virus (rsv) genome. karyotype of the l104 cultures revealed predominantly rat-like patterns; however, about 5% of the cells reacted with hla antibodies and demonstrated human isozyme patterns. electron microscopy of l104 cells revealed the presence of c-type particles bud ... | 1975 | 170217 |
| mapping rnase t1-resistant oligonucleotides of avian tumor virus rnas: sarcoma-specific oligonucleotides are near the poly(a) end and oligonucleotides common to sarcoma and transformation-defective viruses are at the poly(a) end. | the large rnase t1-resistant oligonucleotides of the nondefective (nd) rous sarcoma virus (rsv): prague rsv of subgroup b (pr-b), pr-c and b77 of subgroup c; of their transformation-defective (td0 deletion mutants: td pr-b, td pr-c, and td b77; and of replication-defective (rd) rsv(-) were completely or partially mapped on the 30 to 40s viral rnas. the location of a given oligonucleotide relative to the poly(a) terminus of the viral rnas was directly deduced from the smallest size of the poly(a) ... | 1975 | 170411 |
| infectious dna coding for a temperature-sensitive dna polymerase of the coordinate la335 mutant of rous sarcoma virus (rsv). | | 1975 | 170738 |
| polypeptide composition of cell membranes from chick embryo fibroblasts transformed by rous sarcoma virus. | chick embryo fibroblasts were transformed by the bryan high-titer strain of rous sarcoma virus (rsv-bh), or a mutant (rsv-bh-ta) inducing temperature-dependent transformation. surface membranes from normal and transformed cells were isolated as membrane vesicles by differential centrifugation, and as cell ghosts after zncl2 treatment and separation in an aqueous two-phase system. these preparations were analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate or p ... | 1975 | 170966 |
| identification of the 5' end of rous sarcoma virus rna. | the 5'-terminal triphosphate of the 35s rna isolated from rous sarcoma virus is blocked by 7-methylguanosine in 5' linkage with the penultimate nucleoside which is methylated in the 2'-o-ribose position, a type of endgroup found in all animal mrnas investigated during the past year. the specific nuclease-resistant terminal fragment of rsv rna has the structure 7mg5'ppp5'gmpcp-. this finding supports the belief that rna of rous sarcoma virus represents a (+) strand messenger which may be directly ... | 1975 | 171660 |
| mapping of biological functions on rna of avian tumor viruses: location of regions required for transformation and determination of host range. | a map of the large t1 oligonucleotides of the rna of prague rous sarcoma virus, strain b (pr rsvb) has recently been established (coffin and billeter, submitted for publication). since the rna of rous associated virus, type 1 (rav-1) lacks many of the large 1 oligonucleotides of pr rsv-b and contains others not present in the latter, the rna of recombinants between rav-1 and pr rsv-b could be analyzed with regard to the origin of its sequences. recombinants were selected for transforming capacit ... | 1975 | 174075 |
| microinjection analysis of envelope-glycoprotein messenger activities of avian leukosis viral rnas. | virion rna from the avian leukosis virus rous-associated virus 2 (rav-2) and poly(a)-containing rnas from rav-2-infected chick embryo fibroblasts were microinjected into fibroblasts transformed by the bryan high-titer strain of rous sarcoma virus (rsv), which is deficient in viral envelope glycoprotein. production of infectious rsv following these injections depended upon the viral envelope-messenger activity of the injected rna. this system constituted a sensitive and rigorous assay system for ... | 1977 | 193109 |
| fibroblast surface antigen (sf): the external glycoprotein lost in proteolytic stimulation and maligant transfromation. | it was previously shown that the fibroblast surface antigen (sf antigen, sfa) is composed of polypeptides of high molecular weight 210,000 (sf210) and 145,000 (sf145) and that both of these decrease in quantity after transformation of the fibroblasts by rous sarcoma virus (rsv). the present experiments show that sf210 is a glycoprotein. it is accessible to surface labelling by lactoperoxidase catalyzed iodination. the sf210 molecule is highly susceptible to trypsin on cell surface. anti-sfa anti ... | 1976 | 175031 |
| transformation-enhancing factor(s) produced by virus-transformed and established cells. | chick embryo fibroblasts (cef) and hamster bhk21 cells transformed by the schmidt-ruppin strain of rous sarcoma virus (sr-rsv) release into the culture medium a factor or factors which enhance 2- to 7-fold the formation of transformed foci by chich embryo fibroblasts infected with the bryan strain of rsv (b-rsv). the factor(s) also increase the number of foci failing to revert to normal phenotype at restrictive temperature (41 degrees c) in cultures infected with a temperature-sensitive mutant ( ... | 1976 | 176116 |
| incomplete viral genome in a non-virogenic mouse tumour cell line (rvp3) transformed by prague strain of avian sarcoma virus. | two cell lines, rvp3 and rva4, derived originally from mouse tumors induced by the prague and schmidt-ruppin strain of rsv, respectively, were studied. tall attempts failed to induce infectious virus production in rvp3 cells by fusion with chicken fibroblasts even if the cells were infected with avian leukosis viruses. also, attempts to rescue the viral genome by transfection were unsuccessful. rvp3 cells harboured 31-45% of the viral genome sequences, as was shown by molecular hybridization, an ... | 1977 | 194849 |
| hydrodynamic diameters of murine mammary, rous sarcoma, and feline leukemia rna tumor viruses: studies by laser beat frequency light-scattering spectroscopy and electron microscopy. | we have studied purified preparations of murine mammary tumor virus (mumtv), rous sarcoma virus (rsv; prague strain), and feline leukemia virus (felv) by laser beat frequency light-scattering spectroscopy, ultra-centrifugation, and electron microscopy. the laser beat frequency light-scattering spectroscopy measurements yield the light-scattering intensity, weighted diffusion coefficients. the corresponding average hydrodynamic diameters, as calculated from the diffusion coefficients by the stoke ... | 1976 | 176431 |
| effects of growth conditions on cyclic nucleotide phosphodiesterases of cultured fibroblasts. | cyclic nucleotide phosphodiesterase activities of baby hamster kidney cells (bhk) grown in surface cultures were altered by modifying growth conditions. the untransformed bhk cells grown in medium containing 10% fetal calf serum showed non-linear lineweaverburk plots for cyclic amp phosphodiesterase activity with apparent michaelis constants for cyclic amp of approximately 5 and 30 mum. when these cells were placed in medium containing 1% fetal calf serum, linear kinetic plots for cyclic amp pho ... | 1975 | 178699 |
| virus-specific rna in selected cell lines derived from rsv-induced tumour. | the presence of virus-specific rna in mammalian tumour cell lines of rsv aetiology was studied using molecular hybridization between the pr-rsv 3h-dna probe synthetized by the endogenous rna-directed dna polymerase reaction and cellular rna. it was found that both virogenic xc cells harbouring the full pr-rsv genome and cryptovirogenic rvp3 cells harbouring an incomplete pr-rsv genome contain virus-specific rna. the degree of homology between such rna and pr-rsv 3h-dna probe reached 10--12% in x ... | 1977 | 198254 |
| electron microscopy of rous sarcoma virus genome rna and its heat-dissociated subunits. | native and heat-treated rnas from the purified schmidt-ruppin strain of rous sarcoma virus (rsv) were fractionated by sucrose density gradients in the presence of ribonuclease inhibitor diethyl-pyrocarbonate and observed by electron microscopy. the structure of native 60-70s rna was classified into two forms: tanglefolded type and linear type. in the tangle-folded type double stranded portions were observed in several sites. a high frequency of 60-70s rna were 1.0 mum and 3-3.5 mum in length. mo ... | 1975 | 179284 |
| chicken leukosis virus genome sequences in dna from normal chick cells and virus-induced bursal lymphomas. | genome sequences of two recent field isolates of avian leukosis viruses in the dna of normal and neoplastic chicken cells were studied by dna-rna hybridization under conditions of dna excess. comparisons were made between 60-70s rna from these viruses and that of a chicken endogenous type c virus (rav-0), and of a series of "laboratory" leukosis and sarcoma viruses, by competitive hybridization analysis. a minimum of 18% of the genome sequences of both alv isolates detected in dna from lymphomas ... | 1975 | 164291 |
| infectious dna recovered from avian tumor-virus-producing cells. | a single treatment of chick embryo fibroblasts with dna recovered from chick embryo fibroblasts productively infected and transformed with four different strains of rsv, or productively infected with two different strains of rav, resulted in virus production and cell transformation (in the case of rsv) two or three passages after treatment (8-25 days). the virus recovered from cultures was phenotypically identical to that produced by the donor cells. no virus production nor cell transformation ... | 1975 | 165150 |
| rna of replication-defective strains of rous sarcoma virus. | the rna of a replication-defective (rd) mutant, isolated from stocks of nondefective (nd) schmidt-ruppin rous sarcoma virus of subgroup a (sr-a) and termed sr-n8, was compared to the rnas of sr-a, of a transformation-defective derivative of sr-a (td sr-a) and of rd bryan rous sarcoma virus, rsv (minus). the molecular mass of the 30-40s species of sr-n8 rna was estimated to be 21% (congruent to 7.5 to 8 times 10-5 daltons) smaller than that of sr-a by (i) electrophoresis in polyacrylamide gels an ... | 1975 | 165514 |
| evidence for a host cell surface antigen on the envelope of avian tumour viruses. | avian sarcoma viruses of the a, b, c, d and e subgroups are inactivated about 100-fold by the serum of rabbits immunized against chick embryo (ce) cells, in the presence, but not in the absence, of complement. the inactivation is not due to the action of the antiserum and complement on the ce cell cultures used for virus assay, nor to anti-forssman antibodies, but it is presumably due to antibodies to some antigen(s) common to the surface of ce cells and to the virus envelope. this host cell sur ... | 1975 | 167111 |
| chicken egg yolk enhances focus formation by subgroup b, c and d rous sarcoma viruses. | focus formation by rous sarcoma virus (rsv) was significantly enhanced when virus was incubated with the saline fraction of chloroform extracted chicken egg yolk, prior to infecting chicken embryo cells. the enhancement was restricted to members of rsv subgroups b, c and d and was proportional to yolk dilution. subgroup a virus was never affected. in all, 108 yolk samples from specific pathogen free chickens were investigated. of these 78 to 97% stimulated focus formation. rsv(rav-50) of subgrou ... | 1976 | 182909 |
| membrane lipid acyl group alterations in cells infected with a temperature-conditional mutant of rous sarcoma virus. | the increased percentage of oleic acid and decreased percentage of arachidonic acid which occurs in the lipids of chicken embryo fibroblasts transformed by rous sarcoma virus was shown to be transformation specific rather than a consequence of virus infection. cells infected with a temperature conditional mutant of rous sarcoma virus (rsv-t5) had a normal type fatty acid composition when held at the restrictive temperature of 41 degrees c, but had a transformed type fatty acid composition when h ... | 1976 | 183825 |
| cell-free translation of virion rna from nondefective and transformation-defective rous sarcoma viruses. | nondefective and transformation-defective virion subunit rnas from two strains of rous sarcoma virus (rsv) were translated in cell-free systems derived from krebs iia ascites cells, wheat germ, and l-cells. in each case the predominant viral-specific product was a polypeptide of molecular weight 76,000 that is related to the internal viral group-specific antigens, as judged by immunoprecipitation with monospecific antisera and tryptic peptide fingerprinting. no difference could be detected betwe ... | 1976 | 184305 |
| rescue of rous sarcoma virus (rsv) from rsv-transformed human embryonic cells by cell fusion with chick embryo fibroblasts using lysolecithin. | heterokaryon formation and rous sarcoma virus (rsv)-induction were studied by fusion of rsv-transformed human embryonic cells with chick embryo fibroblasts in the presence of lysolecithin. heterokaryon formation was observed by autoradiography. rsv-induction was identified by focus formation, electron microscopy and density gradient centrifugation of 3h-uridine-labeled particles. the most effective concentration of lysolecithin for virus induction was 10 mug/10(6) cells/0.1 ml. efficiency of lys ... | 1976 | 187016 |
| interactions of concanavalin a with chick embryo fibroblasts transformed by rous sarcoma virus. study with an rsv mutant thermosensitive for transformation. | the interactions between concanavalin a and chick embryo fibroblasts, normal and infected with rous sarcoma virus (rsv-bh) or its thermosensitive mutant rsv-bh-ta, have been studied. normal chick embryo cells and rsv-bh transformed cells showed at 4 and 25 degrees c a similar number of concanavalin a receptors per cell. analysis of the binding data by the scatchard relation showed that apparent changes in binding as a function of temperature are due to the thermodynamic properties of the process ... | 1976 | 187246 |
| sodium: a regulator of glucose uptake in virus-transformed and nontransformed cells. | observations of cells transformed by the bryan strain of rous sarcoma virus (rsv-bh) suggested that the intracellular concentrations of sodium ion (na+) may play a critical role in cellular metabolism. in an attempt to manipulate intracellular na+, chick embryo cells were exposed to graded concentrations of na+ in the cellular growth medium, and the effects on capacity for glucose uptake was examined. after incubation for six hours, the incorporation rate of 2-deoxyglucose (used as a substitute ... | 1976 | 188836 |
| a continuous line of rous sarcoma virus-transformed chick embryo cells. | a continuous line of rous sarcoma virus (rsv)-transformed chick embryo cells was established. the cells, designated rtaz-1, which constitute the only known line of continuously growing rsv-transformed cells of chick embryo origin, grow rapidly, display uniform morphology, and perpetually release large amounts of rsv (rous-associated virus, type 1). rtaz-1 cells display a heteroploid chromosome complement with 92-94 chromosomes characteristic of chicken cells. molecular hybridization studies demo ... | 1977 | 189048 |
| the genome-associated, specific rna binding proteins of avian and mammalian type c viruses. | a structural protein purified from the rous sarcoma virus (rsv) can specificially bind in vitro to purified avian, but not mammalian, type c viral rna. following ultraviolet irradiation of viral particles under conditions which stabilize the polyploid 70s viral rna, the same polypeptide can be directly purified from the rsv genome. based on its electrophoretic mobility in polyacrylamide gels containing sodium dodecylsulfate, the rna binding protein has been identified as the major phosphoprotein ... | 1977 | 189935 |
| body temperature and tumor virus infection. i. tumorogenicity of rous sarcoma virus for reptiles. | rous sarcoma virus (rsv) was oncogenic for the following nine species of reptiles representing 6 families from chelonia and squamata orders: family of testudinidae: 1. testudo horsfieldi, family agamidae: 2. agama sanguinolenta; 3. agama erythrogastra, family lacertidae: 4. eremias persica; 5. eremias velox; 6. eremias grammica, family scincidae: 7. eumeces taeniolatus, family boidea: 8. erix tataricus, 9. ancistrodom blomhoffi. rsv did not induce tumors in 13 studied species of reptiles. histol ... | 1977 | 190549 |
| interferon production in children with respiratory syncytial, influenza, and parainfluenza virus infections. | to better understand the recovery process of infants with lower respiratory tract disease due to respiratory syncytial virus, the production of interferon by 129 children (ages 10 days to 24 months) with rsv infection was compared to that of 20 children with influenza (ages 1 to 36 months), and 37 children with parainfluenza virus infection (ages 4 to 66 months). interferon assays of 285 nasal washes from children with rsv revealed that interferon production occurred in only 5 (4%) of the childr ... | 1978 | 206677 |
| characterization of tumour virus proteins. i. radioimmunoassay of the p27 protein of avian viruses. | the major structural protein of avian oncornaviruses, a core component of about 27000 daltons, has been measured by radioimmunoassay. the purified protein was labelled with 125iodine by chloramine-t method. the immune serum titer was defined as the highest serum dilution able to precipitate 50% of the labelled antigen present in the system. standard competition curve was constructed in order to determine the equivalents of protein, in a system with limiting antibody concentration. in the experim ... | 1977 | 190652 |
| altered sensitivity of rous sarcoma virus transformed cells to inhibition of rna synthesis by alpha-amanitin. | chick embryo cells transformed by rous sarcoma virus (rsv) continue to synthesize 40--50 percent of control amounts of rna following 12--24 hour exposure to 2 microng/ml of the toxin whereas normal chick embryo cells similarly treated synthesize less than 5 percent of control amounts of rna. analysis of cells treated with alpha-amanitin, or the resistant forms i and iii polymerase, do not increase in infected cells over the levels found in uninfected control cells during the first 24 hours follo ... | 1977 | 192178 |
| studies on the synthesis and structure of mitochondrial dna in cells infected by rous sarcoma viruses and on the occurrence of intramitochondrial virus-like particles in certain rsv-induced tumor cells. | 1. the synthesis of mitochondrial dna in cef in vivo at 3,4 and 6 days after infection with rsv (schmidt-ruppin, subgroup a) was progressively stimulated 2 to 4-fold as compared with that in uninfected cef cells grown in parallel. 2. the stimulation of mtdna synthesis in vivo upon transformation was found to be temperature dependent when the thermosensitive mutant of rsv, t5, was used to infect the cells. 3. in contrast to mtdna synthesis, nuclear dna synthesis did not differ in transformed and ... | 1977 | 192995 |
| presence of ribonucleotide sequences complementary to rous sarcoma virus (rsv) rna in chicken cells infected with rsv. | rna--rna molecular hybridization between [125i] rna from rous sarcoma virus virions and rnas isolated from various subcellular fractions, i.e. nuclei, mitochondria, free and membrane-bound polyribosomes, from tumors induced by rsv in chickens resulted in the formation of rnaase-resistant hybrids only with the rna of mitochondria and membrane-bound polysomes. the origin of complementary regions in the rnas from these organelles is discussed. | 1977 | 193629 |
| changes in synthesis of dna-binding proteins during the onset of transformation in nrk cells transformed by a temperature-sensitive mutant of rous sarcoma virus. | synthesis of cytoplasmic dna-binding proteins was investigated after a shift from the nonpermissive to the permissive temperature in nrk cells transformed by a temperature-sensitive mutant of rous sarcoma virus [ts339(rsv)]. cells were labeled for several generations in [3h]leucine and were pulse-labeled with [35s]methionine for 1 h at the nonpermissive temperature (39 degrees c) and at the permissive temperature (33 degrees c, 5 h after shift from 39 degrees c). proteins binding to sequential c ... | 1977 | 194062 |
| formation of reticuloendotheliosis virus pseudotypes of rous sarcoma virus. | superinfection of chicken embryo fibroblasts transformed by the defective bryan strain of rous sarcoma virus (bh-rsv) with two different reticuloendotheliosis viruses (revs), rev strain t (rev-t) or spleen necrosis virus (snv), resulted in the production of infectious sarcoma virus pseudotypes. these pseudotypes were neutralized by antiserum prepared against snv and were unable to infect chicken cells preinfected with either rev-t or snv. these results suggest that defective bh-rsv is able to us ... | 1977 | 195082 |
| transformation of chicken embryo retinal melanoblasts by a temperature-sensitive mutant of rous sarcoma virus. | retinal melanoblasts were transformed by a temperature-sensitive mutant of rous sarcoma virus (ts-rsv). at the permissive temperature for transformation, the cells cease melanin synthesis, degrade their melanosomes and release much of their accumulated melanin into the medium. at the nonpermissive temperature, the cells assume an epithelioid morphology, actively synthesize melanin and become difficult to distinguish from normal uninfected control cultures. both the transformed phenotype and the ... | 1977 | 196765 |
| in vitro translation yields a possible rous sarcoma virus src gene product. | in vitro translation of rous sarcoma virus (rsv) virion rna in the messenger-dependent reticulocyte lysate system yielded polypeptides that were not synthesized by translation of rna from a transformation-defective deletion mutant of rsv. these rsv-specific products migrated on sodium dodecyl sulfate/polyacrylamide gels as two doublets of approximately 25,000 and 17,000 daltons. synthesis of these proteins was not sensitive to inhibition by m7gtp; however, synthesis of the 76,000-dalton precurso ... | 1977 | 198780 |
| [cellular contaminants and structural proteins of rous sarcoma virus (rsv), studied by polyacrylamide gel electrophoresis]. | the number of polypeptides in highly purified preparations of rsv, of two different subgroups, produced in culture, has been compared to the polypeptides present in the supernatant of uninfected cultures and processed in identical manner. the analysis of page-sds shows that from 13 to 18 polypeptides present in viral preparations may be cellular contaminants. fewer contaminating polypeptides are found in the myeloblastosis virus purified from plasma of chicken. | 1977 | 199367 |
| temperature-sensitive changes in surface modulating assemblies of fibroblasts transformed by mutants of rous sarcoma virus. | the hypothesis that surface modulating assemblies containing microfilaments and microtubules and altered after cellular transformation was tested on cells infected with temperature-sensitive mutants of avian sarcoma virus. untransformed cells (mouse 3t3 and chick fibroblasts), cells transformed by simian virus 40 (sv 3t3), and chick fibroblasts infected with schmidt-ruppin strain of rous sarcoma virus (sr-rsv-a-infected cells) were first compared for differences in microfilament and microtubule ... | 1976 | 180536 |
| infectivity of rous sarcoma cell dna: comparison of two techniques of transfection assay. | a dna extracted from a clone of chicken cells transformed by the schmidt-ruppin strain of rous sarcoma virus, subgroup d(sr-rsv-d), was assayed for infectivity by means of deae-dextran and calcium techniques. the calcium technique like the previously described deae-dextran procedure gave rise to viruses in transfection assays with both native and denatured (s1 nuclease susceptible) dnas. the efficiency of these transfection techniques with native dna was compared and found to be about the same p ... | 1975 | 181347 |