ISSN:0192-2521    

DOI:10.1002/em.2860060502

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

年代:1984

数据来源: WILEY

摘要:

AbstractIncubation ofSalmonella typhimuriumunder anoxic conditions (0.1 % oxygen or less) results in a substantial decrease in small (3‐and 6‐basepair) deletions in an A/T‐rich region of thehisGgene in thehisG428ochre mutant and also decreases the frequency of minus frameshift mutations in G/C‐rich sequences in thehisD3052andhisC3076mutants. In contrast, the frequency of G/C→ A/T transition mutations increases substantially during anoxic growth ofhisG46. Growth of revertants of strains carrying accessory deletions in theuvrBregion of theSalmonellachromosome is drastically impaired on glucose minimal medium when oxygen partial pressures are below 0.

ISSN:0192-2521    

DOI:10.1002/em.2860060503

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis research (1) ranked the genotoxicity of methylene chloride extracts of laboratory and environmentally collected particles and (2) evaluated the role of collection location and sample composition on genotoxic potency. Samples of exhaust from a spark‐ignition automobile, light‐duty diesel automobile, and a heavy‐duty diesel engine operated in a laboratory on a dynamometer were studied, as well as samples taken in a highway tunnel and outside the same tunnel. The tunnel samples were collected 30 m inside or 56 m outside the exit portal at times when between 70%‐95% of the traffic consisted of diesel trucks. In the AmesSalmonellamutagenicity assay, each extract produced a dose‐dependent increase in mutagenicity in strain TA‐98 without addition of liver S‐9 fraction. Extracts from two tunnel samples collected 1 yr apart, and extracts of particles collected outside the tunnel had similar mutagenic activity. The order of mutagenic activity per μg of extract in TA‐98 without S‐9 from the lowest to the highest was environmental sample ⩽ tunnel

ISSN:0192-2521    

DOI:10.1002/em.2860060504

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

年代:1984

数据来源: WILEY

摘要:

AbstractWastewater collected from oil‐water separating tanks of ten gasoline stations for a year was fractionated into diethyl ether‐soluble neutral, acidic, and basic fractions. Mutagenicity of these fractions was measured withSalmonella typhimuriumstrains TA98 and TA100 in the presence or absence of S9 mix. The neutral fractions showed high mutagenicity in the absence of S9 mix. Each neutral fraction was subjected to high‐performance liquid chromatography (HPLC) and fractionated. A 1‐nitropyrene(1‐NP)‐corresponding fraction was collected and analyzed by gas chromatography‐mass spectrometry (GC‐MS) and HPLC to prove that wastewater contains 1‐NP and to quantitate 1‐NP in wastewater. GC‐MS patterns showed the following molecular and fragment ion peaks of 1‐NP: 247, 217, 201, and 189. The amount of 1‐NP in 36 samples of wastewater was 4.2–25,600 ng per liter of wastewater, and 1‐NP accounted for O.3–58.5% of the total mutagenicity of the neutral fractions. The other 19 samples of wastewater did not contain any detectable 1‐NP. The mutagenicity of wastewater may be due to water from car washing and contamination by used crankcase oil.A Soxhlet extract of crankcase oil used in a gasoline engine was fractionated into three fractions as above. Mutagenicity was measured with strains TA98, TA100, TA98NR, and TA98/1,8‐DNP6in the absence or presence of S9 mix. The neutral fraction showed the highest mutagenicity with strain TA98 in the absence of S9 mix, and its mutagenicity was decreased in strains TA98NR and TA98/1,8DNP6. The latter result indicates that the used engine‐oil contained 1‐NP and dinitropyrenes. Actually, the amounts of 1‐NP and 1,6‐diNP in used crankcase oil were 138 and 2.0 ng per ml of oil, respectively, and these concentrations accounted for 0.45 and 2.7%, respectively, of the total mutagenicity of the neutral fraction with strain TA98 in the absence of S9 mix. Moreover, the concentrations of 1‐NP and 1,6‐diNP in used crankcase oil of a diesel engine were 349 and 31 ng per ml of oil, respectively, accounting for 0.9 and 12%, respectively, of the total mutagenicity o

ISSN:0192-2521    

DOI:10.1002/em.2860060505

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

年代:1984

数据来源: WILEY

摘要:

AbstractThere are chemicals that affect the number of his + revertant colonies ofSalmonellain the plate test at doses that are apparently nontoxic, but may be causing nonlethal, toxic effects. When mixed with mutagens, these chemicals reduce the numbers of his+ revertant colonies on the plate with no accompanying visible toxic effect on the background lawn. Some of these plates are indistinguishable from spontaneous control plates, leading to the possibility that the mutagens under test would be evaluated as nonmutagenic, or that the mutagenic response would be underestimated. The reduction in mutagen‐induced revertant colonies in most cases is equivalent to the reduction in spontaneous revertants in the absence of mutagen. A spot test that permits a rapid screen of chemicals for inhibitory effects has been developed; a plate incorporation assay is used to confirm the effect. Toxic effects can be seen in the background lawns of plates examined at magnifications of 100 X or greate

ISSN:0192-2521    

DOI:10.1002/em.2860060506

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe effects of chloral hydrate (CH), an in vivo metabolite of trichloroethylene, have been evaluated by cytogenetic observations of mouse secondary spermatocytes after ip treatment with 82.7, 165.4, or 413.5 mg/kg bw. Hyper‐haploid metaphases have been scored to determine whether previous observations in various nonmammalian organisms about an effect of this drug on the mitotic spindle could be confirmed in mice.At each dose, the frequencies of hyper‐haploid cells have been estimated to assess the response of pachytene, preleptotene, premeiotic, and staminal gonial cells. Significant increases above the control value have been observed particularly after treatment of actively dividing gonial cells, confirming the results obtained with the same batch of the drug in a parallel collaborative investigation withAspergillus nidulans.Thus: a) chloral hydrate has been shown to be effective in inducing nondisjunction in a mammalian system; b) a prevalent action on the mitotic spindle has been confirmed and quantified; and c) the usefulness of parallel investigations with different methods is stressed, particularly to collect information about the mechanisms of induction of nondisjunction eve

ISSN:0192-2521    

DOI:10.1002/em.2860060507

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe mutagenic activity of a group of diazo dyes based on benzidine and its congeners was compared following metabolic activation of the dyes through sequential reduction and oxidation. The dyes were reduced by incubating them with either a suspension of rat cecal flora or a hamster S9 mix supplemented with flavin mononucleotide. The products of dye reduction were then subjected to oxidative metabolism by either Aroclor‐induced rat liver S9 or by hamster liver S9; the resultant mutagenic activity was assayed withSalmonella typhimuriumTA1538. Fifteen of the 17 compounds tested were mutagenic, and the degree of mutagenicity was affected by the activity of both the reduction and oxidation systems used. Purified dyes required a reductive step to become mutagenic, but several of the crude dyes did not. All the positive compounds, however, were more mutagenic when the reduction step was included. The mutagenicity of the purified dyes was equal to or greater than that of an equimolar amount of benzidine or appropriate benzidine congener. For the crude dyes, there were no consistent quantitative relationships between the mutagenicity of the dye and that expected from the benzidine moiet

ISSN:0192-2521    

DOI:10.1002/em.2860060508

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

年代:1984

数据来源: WILEY

摘要:

AbstractAdult male South African clawed frogs,Xenopus laevis, were mutagenized by 3‐day immersion in aqueous solutions of ethyl methanesulfonate (EMS), diethyl nitrosamine (DEN), or ethyl nitrosourea (ENU), or by acute exposure to gamma radiation. They were then spawned repeatedly at 2‐week intervals with untreated females, and embryonic survival of the progeny was used to assess genetic damage. Recessive lethal effects were assessed from reduced survival of androgenetic haploid progeny. Neither recessive nor dominant lethal effects were obtained after exposure to 100 mg/liter EMS or 2 g/liter DEN. At 250 mg/liter EMS, peak dominant lethality occurred 3–5 wk after treatment. Most embryos hatched, but many were abnormal and died shortly after hatching. Haploid survival was significantly reduced over a broader period, from 1 to 13 wk after mutagenesis. Treatment with 75 mg/liter ENU produced effects similar to the 250‐mg/liter EMS mutagenesis. At 400 mg/liter EMS, the frequency and severity of the effects on both diploid and haploid embryos were increased over the lower dose. Gamma irradiation at 1,500 R produced effects similar to the 400‐mg/liter mutagenesis, except that peak dominant lethality extended from

ISSN:0192-2521    

DOI:10.1002/em.2860060509

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

年代:1984

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860060510

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

年代:1984

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860060511

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

年代:1984

数据来源: WILEY