摘要:

AbstractThe phenotypic expression time of ethyl methanesulfonate (EMS) induced 6‐thioguanine‐resistant mutants was studied with Chinese hamster ovary cells in culture (CHO/HGPRT system). After mutagen treatment of exponential phase cultures, the cells were maintained either in the exponential phase through subculture in medium containing 5% dialyzed fetal bovine serum (FBS) or in a nondividing viable state by use of medium containing 0–1 % dialyzed FBS. The time course of expression of the 6‐thioguanine‐resistant phenotype was similar with both exponential phase and division‐arrested cultures showing maximum expression by 9 days after mutagen treatment, and both methods of expression also yielded similar mutant frequencies over a range of EMS concentrations. This study shows that once the mutagenic event is fixed, the expression of the mutant phenotype does not require continued cell division since it occurs in division‐arrested cultures. These results also suggest that both dilution of pre‐existing hypoxanthine‐guanine phosphoribosyl transferase (HGPRT) enzyme by cell division and turnover by protein degradation are involved in the phenotypic expression. Both processes occur in exponential cultures, but only protein turnover in arrested cultures. Consistent with this was the demonstration that the rates of total cell protein turnover increased in division‐arrested cultures maintained in serum‐free medium. These results separate genetic damage and phenotypic expression in a temporal sense, and point out the need to consider the mechanisms responsible for each process involved in the induction and ex

ISSN:0192-2521    

DOI:10.1002/em.2860040402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAqueous chlorination of many organic substances has been found to produce substantial mutagenicity in Salmonella typhimurium TA100. An effective way to decrease such mutagenicity is to raise the pH of the solutions to neutrality or higher. The effect of pH on the mutagenicity of the filtrate from the chlorination of unbleached kraft wood pulp and of certain mutagens found in such filtrates has been investigated. The decay of mutagenicity of the known mutagens has been shown to proceed by cleavage of organically bound chlorine by hydroxide ion. Caution is recommended with respect to the practice of raising the pH of solutions for mutagenesis assays.

ISSN:0192-2521    

DOI:10.1002/em.2860040403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractQuantitative dose‐response data were obtained using spiral plating in conjunction with the Salmonella/mammalian microsome test. This plating method provides data comparable to that obtained with standard methods. It requires significantly less time and material and generates more information than standard method

ISSN:0192-2521    

DOI:10.1002/em.2860040404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractA chinese hamster ovary (CHO) cell line heterozygous at the adenine phosphoribosyl transferase (APRT) locus was used for selection of induced mutants resistant to 8‐azaadenine (8AA), 6‐thioguanine (6TG), ouabain (OUA), emetine (EMT) and diphtheria toxin (DIP). The expression times necessary for optimizing the number of mutants recovered at the different loci have been determined using the know direct acting mutagen, far ultraviolet light (FUV), and a complex aqueous organic mixture (shale oil process water) activated with near ultraviolet light (NUV). Our results indicate that optimal expression times following treatment with either mutagen was between 2 and 8 days (depending on the genetic marker examined). For CHO cells treated with shale oil process water and subsequently exposed to NUV a linear dose response for mutant induction was observed for all five genetic loci. At 10% surviving fraction of cells, between 35‐ and 130‐fold increases above background mutation frequencies were observed for the various markers examined. Among the five genetic loci tested, OUARwas the most sensitive marker

ISSN:0192-2521    

DOI:10.1002/em.2860040405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractOzone is a very strong oxidizing agent that may be used in water purification. The effect of ozonation on the mutagenicity of mutagens and/or carcinogens of diverse chemical structures was evaluated as measured by the Salmonella/microsome assay. The effect of ozonation of 36 mutagens and/or carcinogens has been evaluated and the results of 15 reported here. The mutagenicity of polycyclic aromatic hydrocarbons and aromatic amines was inactivated by ozone treatment, while alkylating agents, nitro aromatics, and nitroso compounds were not affected. Ozonation of hydrazines produced mutagenic intermediates that may be susceptible to base‐catalyzed hydrolysis. Therefore, depending on the chemical present, ozonation may be useful in the treatment of waters containing organic carcinogens, including drinking water, waste‐water effluents, and other aqueous waste materials containing carcinog

ISSN:0192-2521    

DOI:10.1002/em.2860040406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractFollowing a number of recent reports on the presence of mutagens in certain foods, a general survey of the mutagenic potential of a wide variety of food products has been initiated. Here, results for samples of 28 widely consumed beverages from 13 general categories are reported. Each sample was concentrated and fractionated by polarity and solubility to give up to seven fractions, each of which was assayed for mutagenic potential with Salmonella typhimurium TA98 and TA100 ± fortified liver homogenate. Fractions showing evidence of either mutagenicity or toxicity were retested at the same and lower concentrations. The utility of the fractionation procedure and the sensitivity of the screening strategy were established by assaying six beverages spiked with known mutagens prior to fractionation. Statistical analysis of the data resulted in positive findings for seven beverages, although confirmation of these results through analysis of a second sample was obtained only for red wine, grape juice, and instant coffee. The remaining 21 beverages showed no strong evidence of mutagenic activity. For those foods for which the variation among replicate plates was largest, the false‐positive rate for the two‐stage screening procedure employed was estimated to be less than 1% while the false‐negative rate for a beverage inducing a threefold increase in the background mutation rate was conservatively estimated to be limited

ISSN:0192-2521    

DOI:10.1002/em.2860040407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe cytotoxic and cytogenetic effect of sodium arsenite and sodium arsenate on Chinese hamster ovary (CHO) cells is reported. Chromosome aberrations were induced with both arsenic compounds. Trivalent arsenic was more clastogenic than pentavalent arsenic. Sodium arsenite was also shown to produce increased sister chromatid exchange in CHO cells and increased chromosome breakage in human lymphocytes.

ISSN:0192-2521    

DOI:10.1002/em.2860040408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860040409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860040410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860040411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY