| modified 5'-nucleotides resistant to 5'-nucleotidase: isolation of 3-(3-amino-3-carboxypropyl) uridine 5'-phosphate and n2, n2-dimethylguanosine 5'-phosphate from snake venom hydrolysates of transfer rna. | a procedure for the quantitative measurement of the o2'-methylnucleoside constitutents of rna has recently been developed in this laboratory (gray, m.w. can. j. biochem. 53, 735-746 (1975)). this assay method is based on the resistance of o2'-methylnucleoside 5'-phosphates (pnm) (generated by phosphodiesterase hydrolysis of rna) to subsequent dephosphorylation by venom 5'-nucleotidase (ec 3.1.3.5). in the present investigation, two base-modified 5'-nucleotides, each displaying an unusual resista ... | 1976 | 6133 |
| the production of chinese hamster interferon. | | 1976 | 11678 |
| the electrophoretic properties and aggregation of mouse lymphoma cells, chinese-hamster fibroblasts and a somatic-cell hybrid. | 1. the electrophoretic mobilities of a mouse lymphoma cell, a chinese-hamster fibroblast and a somatic-cell hybrid (also fibroblastic), produced by fusion of the hamster cell and a mouse lymphoma cell, were measured at 25 degrees c over a range of ph, concentration of ca2+ ions and concentration of la3+ ions. 2. all the cells have pi at ph3.5. 3. ca2+ ions decrease the mobilities and zeta potentials of the cells to zero in the range 1-100mm. 4. la3+ ions lower the mobilities and zeta potentials ... | 1976 | 12752 |
| expression of differentiated functions in hepatoma cell hybrids: ix extinction and reexpression of liver-specific enzymes in rat hepatoma-chinese hamster fibroblast hybrids. | most of the hybrid clones derived from a cross of chinese hamster fibroblasts (don) with rat hepatoma cells (faza 967) showed preferential loss of rat chromosomes. two of the hybrid clones retained the rat chromosomes, and both showed extinction of 4 liver-specific enzymes: aldolase b, liver alcohol dehydrogenase, and the inducible enzymes tyrosine aminotransferase and alanine aminotransferase. subcloning of 1 of these hybrids, which contained 2 sets of hepatoma chromosomes and 1 set of hamster ... | 1975 | 17164 |
| folate-dependent enzymes in cultured chinese hamster cells: folypolyglutamate synthetase and its absence in mutants auxotrophic for glycine + adenosine + thymidine. | | 1977 | 18110 |
| regional assignment of seven genes on chromosome 1 of man by use of man-chinese hamster somatic cell hybrids. i. results obtained after hybridization of human cells carrying reciprocal translocations involving chromosome 1. | regional localization studies of genes coding for human pgd, pph1, pgm1, ugpp, guk1, pep-c, and fh, which have been assigned to chromosome 1, were performed with man-chinese hamster somatic cell hybrids, informative hybrids that retained fragments of the human chromosome 1 were produced by fusion of hamster cells with human cells carrying reciprocal translocations involving chromosome 1. analysis of the hybrids that retained one of the translocation chromosomes or de novo rearrangements involvin ... | 1977 | 18324 |
| mutagenesis by simian virus 40. ii. changes in substrate affinities in mutant hypoxanthine-guanine phosphoribosyl transferase enzymes at different ph values. | a number of 8-azaguanine-resistant clones selected from chinese hamster cells infected with sv 40, and supposed to originate by virus infection was investigated to demonstrate and analyze genetic alterations occurring in the cells after infection. all resistant clones tested showed reduced but detectable activity levels of the enzyme hypoxanthine-guanine phosphoribosyltransferase. the extent of reduction in the activity was not identical for different substrates. in all the clones tested, sponta ... | 1977 | 21348 |
| gamma-glutamyltransferase in human diploid fibroblasts and other mammalian cells. | gamma-glutamyltransferase was determined in wi-38 human diploid fibroblasts and compared to enzyme levels determined in several other mammalian cell lines including: fibroblast-like cells from human skin, tibia and foreskin; epithelial-like cells from human, bovine and monkey kidney; and transformed cells (chinese hamster ovary, hela s3 and sv-40 transformed wi-38). transformed cells had the lowest activity found followed in increasing order by fibroblasts, human and bovine epithelial cells and ... | 1978 | 27446 |
| interspecies interactions of arboviruses. iii. competition for virus envelope antigens in mixed getah and sindbis virus populations. | interactions of getah and sindbis virus populations in mixed infections of 5 tissue systems were competitive or neutral. the type of interaction is regulated by the host cell and virus population density. on reproduction in mouse brains and spev cell cultures the mixed population exhibited antigenic markers of getah virus; in syrian hamster kidney and chick embryo cell cultures those of sindbis virus; and in chinese hamster kidney cell cultures the antigenic markers of both viruses. mixed popula ... | 1978 | 29465 |
| growth of infective forms of trypanosoma (t.) brucei on buffalo lung and chinese hamster lung tissue culture cells. | infective cultures of trypanosoma (t.) brucei (strain 427) have been initiated and maintained on chinese hamster lung tissue culture cells and buffalo lung tissue culture cells. by changing daily one-third of the rpmi-1640 plus 20% fetal bovine serum medium, the cell numbers can be maintained at 2--4 x 10(6) cells/ml. the cultured trypanosomes on these two tissue culture cell types were infective to mice and morphologically similar to bloodstream slender trypomastigotes in having a subterminal k ... | 1978 | 31773 |
| lysosomal arylsulfatase deficiencies in humans: chromosome assignments for arylsulfatase a and b. | genetics of human lysosomal arylsulfatases a and b (aryl-sulfate sulfohydrolase, ec 3.1.6.1), associated with childhood disease, has been studied with human-rodent somatic cell hybrids. deficiency of arylsulfatase a (ars(a)) in humans results in a progressive neurodegenerative disease, metachromatic leukodystrophy. deficiency of arylsulfatase b (ars(b)) is associated with skeletal and growth malformations, termed the maroteaux-lamy syndrome. simultaneous deficiency of both enzymes is associated ... | 1979 | 36611 |
| purification and chemical characterization of the heat-labile enterotoxin produced by enterotoxigenic escherichia coli. | heat-labile enterotoxin (lt) produced by a human strain of enterotoxigenic escherichia coli (286c(2)) was purified to homogeneity from ph extracts of fermentor-grown cells by ultrafiltration, (nh(4))(2)so(4) fractionation, hydrophobic chromatography on norleucine-sepharose 4b, hydroxylapatite chromatography, and bio-gel p-150 filtration. purified lt preparations exhibited biological activity comparable to that of cholera toxin in four bioassays specific for the two enterotoxins (y-1 adrenal tumo ... | 1979 | 39893 |
| mechanism of action of yersinia enterocolitica enterotoxin. | enterotoxin derived from three clinical isolates of yersinia enterocolitica was compared with the heat-stable enterotoxin of escherichia coli. both toxins were biologically active in infant mice examined at 2 h and in ligated rabbit ileal loops at 6 h. neither substance, however, produced changes in ligated ileal loops at 18 h or in chinese hamster ovary or y1 adrenal tissue cultures. in addition, both y. enterocolitica enterotoxin concentrated approximately 20 times by ammonium sulfate precipit ... | 1979 | 39894 |
| identification of interspecific translocation chromosomes in human-chinese hamster hybrid cells. | chromosome material of human and chinese hamster origin can be stained differentially in human-chinese hamster translocation chromosomes by use of the giemsa-11 staining technique. | 1975 | 51825 |
| sister chromatid exchange in human chromosomes from normal individuals and patients with ataxia telangiectasia. | a new fluorescence plus giemsa staining technique now makes the detection of sister-chromatid exchange (sce) a relatively easy matter in cells containing 5-brdu-substituted dna. the technique has been applied to human cells to examine the distribution of sce between different people and within different chromosomes. the results show: (1) that there were no large differences in the incidence of sce between blood leukocyte chromosomes from male and female adults and newborn, and that similar frequ ... | 1975 | 52431 |
| visualization of nucleolar organizer regions im mammalian chromosomes using silver staining. | a simple ammoniacal silver staining procedure, designated ag-as, differentially stains the chromosomal locations of ribosomal dna in certain mammalian species. this was critically demonstrated by ag-as staining of the nucleolus organizer regions in karyotypes of the same species and cell lines used for locating the ribosomal cistrons by dna/rna in situ hybridization. with ag-as, silver stained nors (ag-nors) are visualized as black spherical bodies on yellow-brown chromosome arms. ag-nors were v ... | 1975 | 53131 |
| enterotoxigenic escherichia coli and idiopathic diarrhoea in bangladesh. | faecal escherichia coli from bangalee patients with idiopathic diarrhoea were tested in the chinese hamster ovary cell (c.h.o.) assay to detect production of thermolabile enterotoxin (l.t.). c.h.o-positive e. coli produce both l.t. and a thermostable toxin (s.t.). c.h.o.-positive strains were found in 19.2% of all cases and in 70% of the most severely ill patients with non-vibrio cholera. e. coli which produce s.t. alone were identified in a third of the c.h.o.-negative cases. enterotoxigenic e. ... | 1975 | 53601 |
| enterotoxin testing of escherichia coli causing epidemic infantile enteritis in the u.k. | three test systems were used to study enterotoxin production by epidemic strains of escherichia coli from cases of infantile enteritis in well-documented outbreaks in the u.k. the tests used were the y1-mouse-adrenal-cell test and the chinese-hamster-ovary-cell (c.h.o.) test for the detection of heat-labile enterotoxin and the infant-mouse test for the detection of heat-stable enterotoxin. all 6 outbreaks had been studied using full serotyping techniques and the results had been published. in ea ... | 1976 | 55904 |
| antisera against electrophoretically purified tubulin stimulate colchicine-binding activity. | several rabbit antisera have been prepared against reduced and alkylated, electrophoretically purified tubulin isolated from chick brain. these antisera give a single precipitin line in ouchterlony double diffusion plates when tested against partially purified tubulin, and label specifically microtubule- and tubulin-containing structures, such as mitotic spindles, cilia, and vinblastine-induced crystals, in a variety of cells. the same antisera also display the unique ability to stimulate the co ... | 1976 | 57619 |
| streptozotocin and renal amyloidosis in the syrian hamster. | in the syrian hamster, administration of the drug streptozotocin was associated with an increased incidence and severity of renal amyloidosis. some of the more severely affected animals showed a frankly nephrotic picture. although some of the diseased animals showed decreased levels of serum albumin, no other definite changes in serum proteins were noted, nor was there any evidence of glomerular immunoglobulin or immune complex deposition. none of the lesions previously found after administratio ... | 1976 | 59551 |
| cell surface antigens. iv. immunological coorespondence between glycophorin and the a1 human cell surface antigen. | a stable human-chinese hamster ovary cell hybrid has been produced which, in addition to the complement of chinese hamster ovary (cho-k1) chromosomes, contains only one human chromosome, no. 11. the human cell-surface antigens whose expression is controlled by human chromosome 11, and are expressed by this hybrid, have been defined as the al immunogenetic complex. although one component of this immunogenetic complex (a1) is also expressed by human red blood cells, a second component (a2) is not. ... | 1976 | 61843 |
| a novel chromosome abnormality in human neuroblastoma and antifolate-resistant chinese hamster cell lives in culture. | four cell lines, sk-n-sh, sk-n-mc, sk-n-be(2), and imr-32, established in vitro from tumor tissue of patients with neuroblastoma were analyzed by trypsin-giemsa banding methods. in two of the lines a large, abnormally staining chromosome region was observed. this "homogeneously staining region" (hsr) was considerably longer than any of the bands present in normal human cells and, as revealed by both g- and q-banding, stained with an intermediate intensity. it was located on chromosomes no 6, 10, ... | 1976 | 62055 |
| ten model mutagens evaluated by the micronucleus test. | the following ten mutagenic compounds were subjected to the micronucleus bone marrow test (mnt) in the mouse: cyclophosphamide (ctx), thiotepa (tt), vincristin (vcr), colcemid (colc), adriamycin (am), bleomycin (bm), cytosin arabinoside (ara c), 6-mercaptopurine (6-mp), methotrexate (mtx) and 5-fluorouracil (5-fu). dose-effect curves were established for all compounds. with the exception of ctx, colc and am, the drugs also were subjected to chromosome analyses on chinese hamster fibroblasts in v ... | 1976 | 64925 |
| the expression and relation of hla, beta2-microglobulin and receptor for marmoset red blood cells on man/mouse and man/chinese hamster hybrid cells. | the expression of hla, human and mouse beta2-microglobulin (beta2m), p red blood cell antigen and a receptor for marmoset red blood cells (marbc) were studied on 18 man/mouse and man/chinese hamster hybrids. a positive correlation was found between the expression of hla, p, and the receptor for marbc, which we interpret as a possible synteny between these different loci. we studied 3 hybrid clones where hla antigens are still expressed despite the absence of human beta2m and where redistribution ... | 1977 | 66148 |
| studies on sex chromosomes of four hamster species: cricetus cricetus, cricetulus griseus, mesocricetus auratus, and phodopus sungorus. | in this paper, we present an analysis of the sex chromosomes of four hamster species after application of different staining techniques. the mitotic x chromosomes show a striking similarity in g-banding pattern but rather great differences in their c-banding patterns. a presumably homologous euchromatic segment that exhibits two distinct g-bands appears in the x chromosome of each species. the y chromosome of cricetus cricetus is in contrast to those of the other species, because it reveals a re ... | 1977 | 67011 |
| neutralization of salmonella toxin-induced elongation of chinese hamster ovary cells by cholera antitoxin. | a partially purified preparation of the delayed skin permeability factor from salmonella typhimurium caused chinese hamster ovary cells to elongate. the elongation effect and the skin test activity were blocked by monospecific rabbit antisera against cholera toxin and against the b fragment of cholera toxin, | 1977 | 67084 |
| pretreatment of hamster cells with phenethyl alcohol alters cell surface glycoproteins and inhibits vesicular stomatitis virus growth. | chinese hamster ovary cells cultured in the presence of phenethyl alcohol exhibit obvious changes in cell surface galactose and galactosamine glycoproteins as determined by the galactose-oxidase[3h]borohydride technique and sds gel electrophoresis. cells pretreated with phenethyl alcohol (drug was removed before infection) were not as effective as hosts for vesicular stomatitis virus as untreated cultures. a minimum pretreatment time with 0.1% phenethyl alcohol of about 8 h was required before a ... | 1977 | 68807 |
| identification of a chromosome that controls malignancy in chinese hamster cells. | a chromosome that controls malignancy in chinese hamster cells has been identified by analysis of the giemsa banding pattern of a malignant cell line transformed by simian virus 40 (sv40), non-malignant revertants from this line, segregants from the revertants that were again malignant and a cell line transformed by methylcholanthrene. the malignant cell line transformed by sv40 was near diploid and had gained additional material of chromosome 3. revertants with a suppression of malignancy and m ... | 1977 | 73545 |
| further studies on hybrid cell-surface antigens associated with human chromosome 11. | a new human immunogenetic cell-surface activity associated with human chromosome 11 in the al human-chinese hamster ovary cell hybrid is described. like a1, but not a2, it is present on the human erythrocyte. by mutagenesis and selection, specific, stable, variants of the al hybrid have been prepared exhibiting various combinations of a1, a2, a3, and lactic dehydrogenase a activities. the antigens of the al system can be demonstrated by the horseradish peroxidase system which offers a promising ... | 1977 | 74861 |
| purine mutants of mammalian cell lines: iii. control of purine biosynthesis in adenine phosphoribosyl transferase mutants of cho cells. | spontaneous and mutagen-induced 2,6-diaminopurine-resistant mutants of chinese hamster ovary (cho-k1) cells were isolated. such mutants fell into two classes: spontaneous and ethylmethane-sulfonate-induced mutants had approximately 5% wild-type adenine phosphoribosyl transferase (aprt) activity, whereas icr-170g-induced mutants had barely detectable aprt activity. since it has been reported that human hypoxanthine-guanine phosphoribosyl transferase (hgprt) (lesch-nyhan syndrome) and aprt mutants ... | 1977 | 75575 |
| [modified method of differential staining of sister chromatids]. | a modified method of obtaining differential staining of sister chromatids is described. it is simple, rapid, and effective, and at the same time inexpensive and accessible, since it allows one to use available reagents. when 5-bromdeoxyuridine was administered 24 hours before fixation into the chinese hamster cell culture the percentage of metaphases with a differential chromatid staining constituted 95--98, and when this substance was administered 28 hours before fixation into the human lymphoc ... | 1978 | 75748 |
| a new immunochemical method for the quantitative measurement of specific gene products in man-rodent somatic cell hybrids. | an immunochemical method has been developed for the quantitative determination of species-specific gene products, for instance alpha-galactosidase and n-acetyl-alpha-galactosaminidase, in man-rodent hybrid cells and in the parental cell lines. antisera raised against the purified enzymes are covalently coupled to sepharose 4b. the gene products are specifically removed from a cell lysate by incubating with the appropriate sepharose-coupled antiserum. after centrifugation followed by washing of t ... | 1978 | 83282 |
| molecular mechanisms involved in the production of chromosomal aberrations. i. utilization of neurospora endonuclease for the study of aberration production in g2 stage of the cell cycle. | chinese hamster ovary cells (cho) were x-irradiated in g2 stage of the cell cycle and immediately treated, in the presence of inactivated sendai virus, with neurospora endonuclease (e.c. 3.1.4.), an enzyme which is specific for cleaving single-stranded dna. with this treatment, the frequencies of all types of chromosome aberrations increased when compared to x-irradiated controls. these results are interpreted as due to the conversion of some of the x-ray induced single-stranded dna breaks into ... | 1978 | 83535 |
| induction of high frequencies of endoreduplication in mammalian cell cultures with 33258 hoechst and rubidazone. | cells of the mouse l strain and the chinese hamster cho line were treated with 33258 hoechst, rubidazone, and a combination of these. recovering cell populations following the drug removal exhibited a high frequency (20--50%) of metaphases with diplochromosomes (endoreduplication), especially in the combination treatment series (up to more than 70% in the l strain). such a procedure should be useful in probing the mechanisms of the endoreduplication process. | 1979 | 83930 |
| fibroblast interferon in man is coded by two loci on separate chromosomes. | we have examined viral and poly(rl):poly(rc) induction of interferon synthesis in several human, mouse and chinese hamster cell lines, and in hybrids derived from the fusion of such cells. we observed species and cell-type differences in inducer effectiveness and in the kinetics of interferon production. in some cases, parental characteristics are preserved in somatic cell hybrids, and in other cases, the expression of the donor phenotype is modulated by the epigenetic state of the recipient cel ... | 1979 | 84714 |
| pattern of condensation of mouse and chinese hamster chromosomes in g2 and mitosis of 33258-hoechst-treated cells. | | 1979 | 89960 |
| the relation between chemically induced sister-chromatid exchanges and chromatid breakage. | studies of classical chromosome aberrations and sister-chromatid exchanges (sces) suggest independent mechanisms for the two events despite some common features. examination of chromosome breakage caused by x-rays, visible light, and viruses has shown that few chromatid breaks are accompanied by sces at the sites of breaks. no similar observations were available for chemically induced breaks, but it has been reported that rat chromosomes exposed to dimethylbenzanthracene (dmba) contained a prepo ... | 1979 | 90339 |
| somatic cell genetics of human interferon production in human-rodent cell hybrids. | forty-two primary human-mouse cell hybrids, derived in two separate experiments, were treated with newcastle disease virus (ndv): eight hybrids were found to produce human interferon and this was shown in every case to be predominantly of the fibroblast type. an extensive analysis was made in terms of karyotype and marker enzymes on all the eight hybrids producing interferon and also on five hybrids which did not produce interferon, five randomly selected hybrids and eleven subclones resistant t ... | 1979 | 94346 |
| functional heterogeneity of transferrin-bound iron: iron uptake by cell suspensions from bone marrow and liver and by cell cultures of fibroblasts and lymphoblasts. | according to the hypothesis of fletcher and huehns, functional differences exist between both iron-binding sites of transferrin. the site designated a should mainly be involved in the delivery of iron to erythroid cells, whereas site b should donate its iron preferentially to cells involved in the absorption and storage of iron. in the present study this hypothesis could be confirmed by in vitro experiments with various cell types. iron transferrin preincubated with rat bone marrow cells donates ... | 1978 | 101008 |
| absence of mutagenicity of praziquantel, a new, effective, anti-schistosomal drug, in bacteria, yeasts, insects and mammalian cells. | praziquantel (embay 8440, droncit) a new, effective anti-schistosomal drug, was tested in various short-term assays that have shown a predictive value for the detection of potential carcinogens. indicator organisms s. typhimurium strains, s. pombe, s. cerevisiae, cultured v79 chinese hamster cells or human heteroploid cells and drosophila melanogaster were treated with praziquantel. the induction of reverse and forward mutations, mitotic gene conversions, x-linked recessive lethals, sister-chrom ... | 1978 | 106268 |
| identification of 7,12-dimethylbenz[a]anthracene metabolites that lead to mutagenesis in mammalian cells. | the mutagenicity of 7,12-dimethylbenz[a]-anthracene (dmba) and 11 of its enzymatically derived metabolites was tested with chinese hamster v79 cells for identification of mutagenic metabolites. the metabolites consisted of 7-hydroxymethyl-12-methylbenz[a]anthracene, 7-methyl-12-hydroxymethylbenz[a]anthracene, 7,12-dihydroxymethylbenz[a]anthracene, three trans-3,4-diols, two trans-5,6-diols, and three trans-8,9-diols, all of which derived from dmba or from the hydroxymethyl derivatives. mutations ... | 1979 | 106395 |
| selective growth of some rodent epithelial cells in a medium containing citrulline. | we have defined a medium (called sun's modified waymouth medium) that selectively cultures some rodent epithelial cells that are capable of using citrulline in place of arginine. a growth-response study of the ability of 47 different mammalian cell cultures (of mouse, rat, syrian hamster, chinese hamster, guinea pig, rabbit, monkey, and human origin) to use arginine or its biosynthetic precursors, ornithine, citrulline, or argininosuccinate, showed that all epithelial cells and some fibroblasts ... | 1979 | 109834 |
| isolated liver perfusion--a tool in mutagenicity testing for the evaluation of carcinogens. | an isolated liver perfusion system suitable for the combination with chinese hamster v79 cells is described. with this system, it is possible to study, with the v79 cells as genetic targets, the mutagenic effect of a chemical after metabolic activation in the intact organ. those substances commonly used in mutagenicity testing as inducers of drug metabolising enzymes, i.e. arochlor 1254. phenobarbital(pb) and 3-methylcholantrene(3-mc), were studied for their effect in the isolated perfused liver ... | 1979 | 113109 |
| comparison of mutagenesis and malignant transformation by dihydrodiols from benz[a]anthracene and 7,12-dimethylbenz[a]anthracene. | five dihydrodiols derived from benz[a]anthracene (ba) and 4 dihydrodiols derived from 7,12-dimethylbenz[a]anthracene (dmba) have been tested, together with the parent hydrocarbons, for their abilities to induce mutations to 8-azaguanine resistance in v79 (chinese hamster cells and malignant transformation in m2 mouse fibroblasts. the syn- and anti-isomers of benz[a]anthracene 8,9-diol 10,11-oxide were also tested for biological activity in these two systems. the non-k-region 1,2- and 3,4-dihydro ... | 1979 | 114201 |
| assignment of structural beta-galactosidase loci to human chromosomes 3 and 22. | hybrid cell lines isolated after fusions between chinese hamster e36 cells and normal human white blood cells were analyzed for human beta-galactosidase isoenzymes and for human chromosomes, especially 3, 12, and 22, the candidates for bearing a beta-galactosidase locus. results of neuraminidase treatment of the cell lysates and immunological studies showed that in man two structural beta-galactosidase loci are present and can be assigned to chromosomes 3 and 22. no correlation was found between ... | 1979 | 116956 |
| diabetogenic effects of n-nitrosomethylurea in the chinese hamster. | to evaluate the role of the glucose residue of the diabetogenic substance streptozotocin, the effect of its aglucone derivate n-nitrosomethylurea was tested in chinese hamsters. at a dose of 50 mg/kg body weight of n-nitrosomethylurea a triphasic blood glucose curve was recorded with an initial hyperglycaemic peak after 3 hours followed by a decrease at 6 hours. after 24 hours and during the following days the values were moderately elevated. there was a high mortality in the diabetic animals, a ... | 1975 | 125026 |
| rate and time of dna synthesis of individual chinese hamster cells. | the duration of dna synthesis of a diploid cell line of chinese hamster fibroblasts was determined in a comparative study by the flm technique, and also by a new technique for measuring the rate of dna synthesis of individual cells. these methods produced comparable results when applied during exponential growth of the cells. the rate of dna synthesis was measured by means of quantitative autoradiography following a short-term incubation of the cells with 5 x 10(-6) m fudr and 10(-5) m 14c-tdr. ... | 1975 | 126804 |
| mutation induction by the antischistosomal drug f30066 in various test systems. | the genetic activity of furapromidium (f30066), an antischistosomal drug, was studied in salmonella typhimurium, saccharomyces cerevisiae, neurospora crassa and cultured chinese hamster cells. the results show that f30066 induces gene mutations in s. typhimurium, n. crassa and chinese hamster cells. this compound also causes gene conversions in s. cerevisiae. | 1977 | 138086 |
| human bronchus-mediated mutagenesis of mammalian cells by carcinogenic polynuclear aromatic hydrocarbons. | cultured human bronchial explants activated benzo[alpha]pyrene (bzap) into electrophilic metabolites that bind to dna in bronchial epithelial cells. promutagenic and mutagenic metabolites of bzap were also released into the culture medium. an increase in mutation frequency for ouabain resistance was found in chinese hamster v-79 cells when they were cocultivated with bronchial explants in the presence of bzap. the proximate carcinogenic form of bzap, the 7,8-diol [(+/-)-r7,t8-dihyroxy-7,8-dihydr ... | 1978 | 148049 |
| liver cell-mediated mutagenesis of mammalian cells by liver carcinogens. | a cell-mediated mutagenesis assay using primary cultures of rat liver cells and v79 chinese hamster cells has been developed. liver carcinogens and their structural analogues were studied. mutations in the v79 cells were characterized by resistance to ouabain. cocultivation of the liver cells and v79 cells in the presence of the carcinogens n-nitrosodimethylamine, n-nitrosodiethylamine, and aflatoxin b1 caused the induction of ouabain-resistant mutants of v79 cells. in the absence of liver cells ... | 1978 | 149308 |
| induction of sister chromatid exchanges by nicotinamide in chinese hamster lung fibroblasts and human lymphoblastoid cells. | | 1979 | 160224 |
| simian virus 40 functions required for the establishment and maintenance of malignant transformation. | members of the five classes of temperature-sensitive simian virus 40 mutants were tested for their ability to transform chinese hamster lung cells. two criteria for transformation were used: the ability to form clones in medium with low serum concentrations and the ability to overgrow a monolayer. only a mutants failed to transform at the restrictive temperature when subconfluent chinese hamster lung monolayers were used. however, both a and d mutants failed to transform at the restrictive tempe ... | 1975 | 163374 |
| detection by means of cell fusion of macromolecular synthesis involved in the reconstruction of the nuclear envelope in mitosis. | using the cultured chinese hamster cell line don, g1 or s or a mixture of late-s/g2 cells were prepared by release from metaphase arrest. metaphase (m) cells were also obtained by mitotic arrest of log-phase cultures with colcemid and held in metaphase; such m cells remained untreated with any other compound and were termed standard m cells. when interphase (i) cells were fused at ph 8.0 and 37 degrees c with standard cells in the presence of colcemid by means of uv-inactivated sendai virus, bin ... | 1975 | 163831 |
| cellular adsorption function of the sialoglycoprotein of vesicular stomatitis virus and its neuraminic acid. | exposure of vesicular stomatitis (vs) virions to neuraminidase resulted in loss of their ability to agglutinate goose erythrocytes and to attach to l cells concomitant with hydrolysis of sialic acid. these viral adsorptive functions were also destroyed by tryspsinization. sialyl transferase resialylation in vitro of neuraminidase-treated vs virions restored their hamagglutinating and adsorptive functions almost to original levels. erythrocyte and l cell receptors for attachment of vs virions wer ... | 1975 | 163924 |
| hudrolysis of butyryl derivatives of adenosine cyclic 3':5'-monophosphate by chinese hamster ovary cell extracts and characterization fo the products. | | 1975 | 164439 |
| mutant hamster cells exhibiting a pleiotropic effect on carbohydrate metabolism. | sixty-seven galactose negative (gal minus) clones were established from survivors after treatment of chinese hamster lung (v79) cells with 5-bromodeoxyuridine and black light. the mutational origin of these clonal isolates was inferred on the basis of the previously demonstrated mutagenic action of the combined treatment, persistence of the gal minus phenotype in cell progeny in the absence of selection, conditional lethality of three isolates, interallelic complementation, and assignment of a h ... | 1975 | 164654 |
| changes in lactate dehydrogenase enzyme pattern in chinese hamster cells infected and transformed with simian virus 40. | the lactate dehydrogenase (ldh) isozyme patterns of consecutive passages of chinese hamster embryo cultures were monitored. at early passages the population displayed two ldh bands, m4 and m3h; however, at higher passages the cultures exhibited m2h2, m2h, and m4. when primary cultures of chinese hamster embryo cells were infected with simian virus 40 (sv40), no change in the ldh pattern was observed; however, the total activity of ldh increased. twenty-three of 25 transformed colonies isolated f ... | 1975 | 167939 |
| the effects of several croton oil constituents on two types of dna repair and cyclic nucleotide levels in mammalian cells in vitro. | the purpose of the present study was to determine the effects of two potent tumor-promoting agents on two dna repair mechanisms and cyclic nucleotide levels in mammalian cells. human amnion (av3) cells were treated with low dose levels of either uv of n-acetoxy-acetylaminofluorene. subsequently, dna excision repair as measured by unscheduled dna synthesis was followed in the absence or presence of non-toxic levels of either 12-o-tetradecanoylphorbol-13-acetate (tpa), phorbol-12,13-dibenzoate (pd ... | 1975 | 168978 |
| site of synthesis of membrane and nonmembrane proteins of vesicular stomatitis virus. | upon infection of chinese hamster ovary cells (cho), vesicular stomatitis (vsv) virus synthesizes two membrane proteins (the vsv glycoprotein and the vsv matrix or membrane (m) protein) and three nonmembrane proteins (the vsv nucleocapsid, the viral transcriptase, and an ns protein). we have used the vsv-infected cell as a model system for the study of the site of synthesis of these membrane and nonmembrane proteins. we have isolated vsv mrna from free polyribosomes, membrane-bound polyribosomes ... | 1975 | 169263 |
| a rapid electrophoretic technique for human and chinese hamster galactokinase. | | 1975 | 170194 |
| induction of gene mutations and chromosomal aberrations by simian virus 40 in cultured mammalian cells. | induction of gene mutations by sv40 was studied in aneuploid human and chinese hamster cells. in chinese hamster cells sv40-induced chromosome aberrations were also studied. sv40 penetrated into the cells of both lines and induced synthesis of the t antigen. the efficiency of infection in chinese hamster cells was tested additionally by their ability to form colonies in medium lacking the serum growth factor. the maximal number of cells with serum growth factor independence was observed on the f ... | 1975 | 172787 |
| thermolabile t (tumor) antigen from cells transformed by a temperature-sensitive mutant of simian virus 40. | partially purified tumor (t) antigen from a strain of chinese hamster lung cells transformed by wild-type simian virus 40 (sv 40) and either of two temperature-sensitive sv 40 mutants has been studied as a dna binding protein. the dna binding activity present in the t-antigen-containing fractions is inhibited by purified hamster anti-t igg but not by equivalent amounts of nonimmune hamster igg. t from either wild-type- or tsc219-transformed cells is relatively stable during heating at 44 degrees ... | 1975 | 172906 |
| growth of enveloped rna viruses in a line of chinese hamster ovary cells with deficient n-acetylglucosaminyltransferase activity. | sindbis and vesicular stomatitis viruses were grown in a line (termed 15b) of chinese hamster ovary (cho) cells that is deficient in a specific udp-n-acetyl-glucosamine:glycoprotein n-acetylglucosaminyltransferase. both viruses replicated normally in the cell line, but the glycoproteins of the released virus migrated faster on sodium didecyl sulfate-polyacrylamide gels than did glycoproteins of virus grown in parent cho cells. digestion of the viral glycoproteins with pronase followed by gel fil ... | 1975 | 173886 |
| the effects of serum concentration on the level of integration of simian virus (sv40) genome and the transformation frequency in sv40-infected chinese hamster cells. | | 1976 | 174291 |
| simian virus 40-chinese hamster kidney cell interaction. i. relationship of chromosome changes to transformation. | after approximately 20 in vitro passages, chinese hamster kidney (chk) cell cultures transformed upon exposure to different strains of sv 40 can show a diploid modal chromosome number of 22 with chromosome counts exclusively or essentially in the diploid range (20-25). in primary culture and at the 5th-7th subculture, tumors produced in nude mice by such cells can display a diploid modal value of 22 chromosomes. numerical chromosome variations and karyotype abnormalities observed in chk cells tr ... | 1975 | 174521 |
| [stimulation of sv40 virus replication in chinese hamster kidney cells by treatment of the cells with mitomycin c]. | the production of virions by chinese hamster kidney cells infected with sv 40 dna is increased 10 to 100 fold by mitomycin c treatment. this observation has been confirmed for different cell clones. the optimum concentration of mitomycin c has been determined. | 1975 | 174828 |
| persistent reovirus infection of cho cells resulting in virus resistance. | we obtained a persistently infected line of chinese hamster ovary cells by selection for resistance to reovirus infection. the cells were persistently infected by a population of viruses that were (i) cytopathic for parental chinese hamster ovary cells and (ii) similar to wild-type reovirus in molecular characteristics. the growth rate, plating efficiency, and morphology of the cells were altered. a large majority of the cells in the population were infected. there was no detectable interferon p ... | 1976 | 176428 |
| chromosomally depleted interspecific hybrid cell clones selected with cytotoxic antisera: utilization in the study of control of murine leukemia virus host-range. | a chromosomally stable mouse-chinese hamster hybrid cell line was subjected to five rounds of selection with cytotoxic antisera raised in rabbits against either the parental mouse 3t3 cells or the parental chinese hamster wg-1 cells. routine karyological analysis of clones isolated at each stage of serum selection revealed that treatment with either serum resulted in a limited loss of chromosomes (compared to the untreated hybrid cell cultured in parallel) and that the pattern of chromosome loss ... | 1976 | 176536 |
| assignment of the ak1:np:abo linkage group to human chromosome 9. | in man-chinese hamster somatic cell hybrids the segregation patterns of the loci for 25 human enzyme markers and human chromosomes were studied. the results provide evidence for the localization of the gene for adenylate kinase-1 (ak1) on chromosome 9. since the loci for the abo blood group (abo), nail-patella syndrome (np), and ak1 are known to be linked in man, the abo:np:ak1 linkage group may be assigned to chromosome 9. | 1976 | 176661 |
| simian virus 40-chinese hamster kidney cell interaction. ii. the semipermissivity of the cell system. | throughout in vitro passages, chinese hamster kidney (chk) cells progressively lost susceptibility to sv 40 virus infection while remaining continuously susceptible to viral dna infection. upon infection with sv 40 virus or viral dna, the chk cell line supported viral dna and virus replication at a low level. sv 40 transformed chk cell lines spontaneously produced small amounts of viral dna and virions. the percentage of virus-producing cells was low. various clones derived from each of these li ... | 1976 | 176967 |
| enhanced sv 40-virus replication in chinese hamster kidney cells pretreated with 5-iodo-2'-deoxyuridine. | sv40 virion production was enhanced when semipermissive chinese hamster kidney cells were treated with 5-iodo-2'-deoxyuridine (iudr), prior to infection either with virus or viral-dna. pretreatment did not increase sv40 replication in fully permissive monkey kidney and nonpermissive syrian hamster or mouse embryo cells. | 1976 | 176975 |
| induction by short-chain fatty acids of alkaline phosphatase activity in cultured mammalian cells. | short-chain fatty acids, such as propionic, n-butyric, n-butyric, n-valeric, isovaleric, n-caproic, and n-caprylic acids, induce alkaline phosphatase activity in cultured mammalian cells. long-chain fatty acids have no similar effects. with b-6 cells (mouse x chinese hamster cell hybrids), n-butyrate at 2 to 5 mm exhibits the greatest activity. induction begins exponentially about 24 hours after addition of the fatty acid and continues over 48 hours. studies on the inducing activity-structure r ... | 1976 | 177433 |
| [mutagenesis under the influence of simian vacuolating virus 40 (sv40). i. induction of chromosome aberrations in chinese hamster cells during the first days following infection]. | chromosome aberrations were studied in cultured chinese hamster cells on the 1--4th days after infection with simian virus 40. in the first and second mitoses after infection a statistically significant increase of the percentage of aberrant metaphases was observed (up to 22% as compared to 8--10% in intact cells). already after 3 days following treatment the percentage of aberrant metaphases decreased sharply, reaching the control level. the virus induced a significant increase of the frequency ... | 1975 | 178571 |
| [mutagenesis under the influence of simian virus 40 (sv40). ii. induct?ion of mutations resulting in resistance to purine base analogs in human and chinese hamster cells]. | induction of gene mutations by sv40 was studied in aneuploid human and chinese hamster cell lines. it is shown that sv40 penetrates into the cells studied and induces the t-antigen synthesis. the efficiency of the infection in chinese hamster cells was tested additionally by the ability of infected cells to form colonies in the medium lacking serum growth factor. the maximal number of colony-forming cells was detected 24 hours after the infection. by culturing cells in factor-free medium a chine ... | 1975 | 178572 |
| the induction of sv40-transformed chinese hamster and mouse kidney cells by mitomycin c. | the induction by mitomycin c (mc) of sv40 production in three lines of semi- or nonpermissive sv40-transformed cells is described. the production of virions by a line of semipermissive, virus-shedding chinese hamster kidney cells is increased 1,000-fold by mc treatment; the proportion of infectious centers and v-antigen-containing cells is increased to a lesser degree, suggesting that both the burst per cell and the number of virus-producing cells are increased. mc treatment induces the producti ... | 1975 | 178625 |
| resting state in normal and simian virus 40 transformed chinese hamster lung cells. | normal cell deprived of amino acids or serum factors enter a resting state, whereas cells transformed by wild-type simian virus 40 do not. the ability to enter a resting state is temperature-sensitive (ts) in cells transformed by a tsa mutant of simian virus 40. we shown further: (i) that when complete medium is added to resting cells, the length of time until the onset of dna synthesis often exceeds the length of g1 in growing cells; (ii) that the length of this interval depends upon the condit ... | 1976 | 179093 |
| [protective effect of thymidine in relation to the cytostatic action of cyclic adenosine-3', 5'-monophosphate in mammalian cell cultures]. | under the action of lmm of cyclic adenosine-3',5'-monophosphate (camp) the survival and the rate of reproduction of the cells of chinese hamster in the culture decreased in comparison with control to 27 and 42%, respectively. addition of 0.02 mm thymidine together with camp almost completely eliminated the cytostatic action of the latter. thymidine also prevented the cytostatic effect of noncyclic 5'-amr, but failed to influence the death of the cells with the action of dibutyril camp and theoph ... | 1975 | 179557 |
| laboratory investigation of diarrhea in travelers to mexico: evaluation of methods for detecting enterotoxigenic echerichia coli. | a laboratory investigation was conducted on cultures collected from travelers before, during, and after a trip to mexico to characterize the etiology of traveler's diarrhea. four laboratory methods for detecting enterotoxigenicity of escherichia coli were evaluated: the infant mouse assay, the chinese hamster ovary (cho) cell assay, the y1 adrenal cell assay, and the rabbit ileal loop. although a number of common enteric pathogens were identified as a cause of traveler's diarrhea, including six ... | 1976 | 180047 |
| the selection of virus-resistant chinese hamster ovary cells. | we have selected chinese hamster ovary (cho) cells resistant to infection by encephalomycarditis (emc) virus. thus far, we have obtained five lines resistant to emc, all of which manifest different phenotypes. three of the five are not persistently infected with virus, while two lines produce infectious virus and grow in its presence. the nonpersistently infected lines exhibit different resistance profiles to the other viruses we have tested, and they are stable in nonselective growth conditions ... | 1976 | 182382 |
| [mutagenesis under the influence of simian virus 40 (sv40). ii. induction of mutations for resistance to analogs of purine bases in human and chinese hamster cells]. | induction of gene mutations by sv40 was studied in aneuploid human and chinese hamster cell lines. it is shown that sv40 penetrates into the cells studied and induces the t-antigen synthesis. the efficiency of the infection in chinese hamster cells was tested additionally by the ability of infected cells to form colonies in the medium lacking serum growth factor. the maximal number of colony-forming cells was detected 24 hours after the infection. by culturing cells in factor-free medium a chine ... | 1975 | 182615 |
| mutagenesis by simian virus 40. i. detection of mutations in chinese hamster cell lines using different resistance markers. | the mutagenic action of sv40 in permanent lines of chinese hamster cells (cho-k1 and v79) was investigated with the aid of different resistance markers. the markers studied had resistance to 8-azaguanine (25 and 30 mug/ml), aminopterin (3.3--5.5x10(-3) mug/ml), colchicine (6.5 and 7.0x10(-2) mug/ml) and 5-bromodeoxyuridine (50--120 mug/ml), respectively. after virus infection the mutation frequencies were increased by one (azaguanine, aminopterin) and two (colchicine) orders of magnitude as comp ... | 1976 | 184380 |
| ultrastructural study of the adenohypophysis of the chinese hamster. | the adenohypophysis of normal chinese hamsters of both sexes was examined ultrastructurally. organs were fixed by intravascular perfusion with s-collidine-buffered glutaraldehyde solution. seven types of cells were differentiated and, according to morphological characteristics, classified as (1) mammotropes, with very large (400-800 nm) polymorphous secretory granules; (2) somatotropes, either in the storage phase with numerous large, dense granules (average 300 nm), or in the hormone synthesis ... | 1976 | 184639 |
| confirmation of the assignment of the locus determining ada to chromosome 20 in man: data on possible synteny of ada and itp in human-chinese hamster somatic cell hybrids. | | 1976 | 185012 |
| chromosomal assignment of the gene for human red cell adenylate kinase (ak1) in man-chinese hamster somatic cell hybrids. | | 1976 | 185020 |
| simian virus 40 mutants carrying two temperature-sensitive mutations. | five temperature-sensitive mutants of simian virus 40 containing two temperature-sensitive mutations were isolated. the double mutant of the a and d complementation groups, like the d mutants, failed to complement by conventional complementation analysis and did not induce host dna synthesis at 40 degrees c. however, under conditions that suppressed the d defect, the a:d double mutant expressed only the a defect. thus, viral dna replication dropped rapidly after this mutant was shifted from perm ... | 1976 | 185417 |
| [transmission and expression of malignancy in somatic hybrid cell lines (hamster/hamster, mouse/mouse, hamster/mouse)]. | various characteristics of transformation were studied in subclones isolated from a hybrid cell line obtained by fusion of two chinese hamster sub-lines having the same origin but presenting different properties, particularly in respect to heterotransplantability. different subclones were obtained by cloning on semisoft agar. transplantability, plating efficiency, agglutinability by concanavalin a and actinomycin d resistance were studied in parallel with the evolution of the karyotype to try to ... | 1976 | 186142 |
| transformation of chinese hamster embryo cells with an avian sarcoma virus ts mutant. | chinese hamster embryo cells were transformed with temperature-sensitive mutant of the schmidt-ruppin strain of rous sarcoma virus-subgroup a (ts ny68s ra-a). the developed cell line elicited the morphological transformation at a permissive temperature of 35 degrees c, whereas after a shift to a non-permissive temperature of 40 degrees c the cells reverted to a normal phenotype. tests for the presence of avian sarcoma group-specific antigen showed that the antigen was not expressed both at permi ... | 1976 | 186335 |
| evolutionary trends in 18s ribosomal rna nucleotide sequences of rat, mouse, hamster and man. | the large t1 ribonuclease fragments of 18s ribosomal rna from four mammalian species, rat, mouse, hamster and man, were compared by two-dimensional homochromatography fingerprinting. the nucleotide sequences of the large t1 ribonuclease fragments, polypyrimidines and polypurines which were different among the four mammalian species were determined and compared. the method used for determining nucleotide sequences utilizes 32p-labeling of oligonucleotides at their 5'-termini by polynucleotide kin ... | 1976 | 188015 |
| effects of temperature and antibody on the cyclid growth of vesicular stomatitis virus. | to see the effects of temperature on the interrelated cyclic production of standard and defective interfering (di) particles of vesicular stomatitis virus, a temperature-sensitive (ts) g114 mutant was passaged successively at different temperatures and the production of the two types of viral particles as well as the ability of chinese hamster ovary cells to survive each passage was continuously monitored. when the temperature was nonpermissive for standard virus, the synthesis of both standard ... | 1977 | 189064 |
| assembly of viral membranes. i. association of vesicular stomatitis virus membrane proteins and membranes in a cell-free system. | we report here an in vitro system designed to study the interactions of vesicular stomatitis virus (vsv) proteins with cellular membranes. we have synthesized the vsv nucleocapsid (n) protein, nonstructural (ns) protein, glycoprotein (g protein), and membrane (m) protein in a wheat germ, cell-free, protein-synthesizing system directed by vsv 12 to 18s rna. when incubated at low salt concentrations with purified cytoplasmic membranes derived from chinese hamster ovary cells, the vsv m andg protei ... | 1977 | 189082 |
| assignment of the integration site for simian virus 40 to chromosome 17 in gm54va, a human cell line transformed by simian virus 40. | gm54va human cells transformed by simian virus 40 (sv40) were fused with peritoneal macrophages obtained from three different mouse strains. all 27 hybrid clones studied were positive for sv40 tumor antigen in 100% of their cells and contained human chromosome 17. human chromosome 17 was the only human chromosome present in five of the hybrid clones. fusion of gm54va cells and either thymidine kinase (ec 2.7.1.75)-deficient mouse or chinese hamster fibroblasts resulted in the growth in hypoxanth ... | 1977 | 189310 |
| variation in enterotoxigenicity of escherichia coli. | the possibility that the variable severity of diarrheal disease due to enterotoxigenic escherichia coli might be explained by quantitative differences in the activity of heat-labile enterotoxin was examined. the amount of toxin secreted by 13 enteropathogenic strains of e. coli was quantitated by measurements of the toxin-dependent increase in adenosine 3':5'-cyclic phosphate (cyclic amp) in chinese hamster ovary cells. the activity ranged from 150 pmol of cyclic amp/ml per mg of protein to 4,04 ... | 1977 | 190329 |
| chromosomal assignment of the gene for human red cell adenylate kinase (ak1) in man-chinese hamster somatic cell hybrids. | | 1976 | 192371 |
| heterogeneity of karyotype and growth potential in simian virus 40-transformed chinese hamster cell clones. | five clones of chinese hamster cells transformed with simian virus 40 (sv40) were isolated from methylcellulose and characterized as to giemsa-banded karyotype, dna content, saturation density, agglutination with concanavalin a, and tumorigenicity. chromosome analysis and dna content studies at early passage revealed that the genetic complement for all clones was predominantly near tetraploid. all cultures examined contained a proportion of hypertetraploid cells. nonrandom chromosome changes inc ... | 1977 | 192902 |
| mechanism of action of inosine dialdehyde (nsc 118994) in the inhibition of proliferation of tumor cells in culture. | inosine dialdehyde (inox), the periodate oxidation product of inosine, inhibited the proliferation of various tumor cell lines in suspension culture in a concentration-dependent manner. a concentration of about 1 mm was required to completely inhibit the proliferation of novikoff rat hepatoma and mouse l-cells, whereas about 0.1 mm completely inhibited the proliferation of l1210 and p388 mouse leukemia and chinese hamster ovary cells. inox inhibited in a similar time- and concentration-dependent ... | 1977 | 193637 |
| purineless death: ribosomal rna turnover in a purine-starved ade- mutant of chinese hamster cells. | when v79 pur 1, a purine-requiring auxotroph of a chinese hamster cell line, is deprived of adenine, nucleic acid and protein synthesis decline rapidly. however, on continuous starvation rna and dna synthesis recommences to reach approximately 30% of the normal level between 12 to 24 h starvation. this is accompanied by a rise in the intracellular nucleotide pool. utilizing mengovirus, which gives a productive infection in v79 pur 1 cells even under conditions of starvation, we can show that rrn ... | 1977 | 195948 |
| simian virus 40-chinese hamster kidney cell interaction. iii. characteristics of chemical induction in a clone of virogenic transformed cells. | a number of chemical and physical agents were screened to determine their effectiveness in inducing simian virus (sv40) production in a virogenic clone of sv40-transformed chinese hamster cells. mitomycin c (mc) was the most effective inducing agent, and mc induction was further characterized. it was found that levels of infectious sv40 dna were increased above control levels as early as 6 h after addition of mc to the culture medium and reached maximum levels by 48 h. virus capsid (v) antigen a ... | 1977 | 196036 |
| simian virus 40-chinese hamster kidney cell interaction. iv. enhanced virus replication in infected cells upon treatment with mitomycin c. | chinese hamster kidney cells are semi-permissive to simian virus 40 (sv40). exposure to mitomycin c (mc) of chinese hamster kidney cells infected with sv40 dna enhanced the yield of infectious virus 10- to 100-fold. this stimulation occurred whether the treatment was performed before or after infection. a simultaneous increase in the number of v antigen-synthesizing cells and virus-producing cells, as well as the virus burst size, was observed upon mc pretreatment, whereas the proportion of t an ... | 1977 | 196038 |
| correlation between changes in intracellular level of cyclic amp, activation of cyclic amp-dependent protein kinase, and the morphology of chinese hamster ovary cells in culture. | | 1977 | 196552 |
| initiation points for dna replication in nontransformed and simian virus 40-transformed chinese hamster lung cells. | randomly growing chinese hamster lung cells were pulse-labeled with 3h-thymidine, and the replicating forks of individual dna fibers were visualized by autoradiography. when grown in complete medium, wild-type sv40-transformed cells had more forks per unit length of dna than nontransformed cells. in isoleucine-depleted medium, wild-type sv40-transformed cells had fewer forks per unit length than those few nontransformed cells (1-3% of the population) which continued dna replication. cells transf ... | 1977 | 196764 |