TC─101消毒剂对大鼠的致畸性研究

ＴＣ─１０１消毒剂对大鼠的致畸性研究刘沛玉，张月兰，蒋中仁，郭明（四川省卫生防疫站成都６１００３１）ＴＣ─１０１消毒剂即二氯异氰尿酸钠的二水化合物，是一种高效、快速的杀菌消毒剂，一般毒性及致突变性研究表明为低毒、弱蓄积物质，未见诱变作用。本文进一步就...     

双核微核法检测煤尘遗传毒性的研究

用双核微量核法对三种煤尘亚硝化前后的致突变性进行检测，结果未经亚硝化时，三种煤尘均呈现致突变作用；而在酸性条件下被亚硝化后，二种烟煤表现出了致突变性能。试验提示，在检测煤尘致突变作用中，体外细胞双核微核法的灵敏度高于传统微核法。     

化合物致突变／致癌活性自动检测的研究

本文阐述如何利用电子计算机对生物学试验所提供的信息进行构效分析,预测化合物的致突变/致癌活性。介绍采用分子结构片段为结构参数的方法所建立的(化学)结构—(生物学)活性相关分析的 SARA 系统,找出化合物生物活性与其内部结构关系规律,实现在生物学检测基础上的计算机预测,从而使 SARA 系统预溯化合物致突变/致癌活性的辅助手段。     

对20种抗肿瘤药物的致突变性研究

本文报告用噬菌体诱导试验对20种抗肿瘤药物的致突变性进行筛选,并用Ames试验、SOS固体显色试验和噬菌体诱导试验3种方法联合测试其中11种药物的致突变性,各种试验方法均做加和不加大鼠肝脏微粒体酶代谢活化系统(S9)的两种试验。结果15种药物有致突变作用,阳性率为75％。三种试验方法联合检测的符合率为72.73％。     

重庆市居住区大气不同粒径颗粒物的致突变性和致癌性

重庆市居住区大气不同粒径颗粒物的致突变性和致癌性高宁，张晓丽，卓鉴波，曹波，邱志群（重庆第三军医大学环境卫生学教研室６３００３８）采用Ａｍｅｓ试验检测重庆市居住区大气不同粒径颗粒物的致突变性，用划痕标记染料示踪技术（ＳＬＤＴ）研究其对ＮＩＮ３Ｔ３细胞...     

Ames试验检测氨基苯类化合物的致突变性

Ａｍｅｓ试验检测氨基苯类化合物的致突变性闫春生，赵晓红（兰州医学院预防医学系７３００００）氨基苯类化合物具有许多特殊的性质，因而用途极为广泛，而且新合成的此类化合物仍在不断增加，化学结构也趋于复杂，其环境污染问题日益严重。研究这类化合物的致突变活性，...     

TX－1型净水剂的致突变性研究

ＴＸ－１型净水剂的致突变性研究刘沛玉，张月兰，蒋中仁四川省成都卫生防疫站成都６１００３１ＴＸ－１型净水剂是一种以泥煤、铝屑、盐酸等为主要原料制成的一种金属络合物，样品呈棕黑色粘稠液体，一般毒性试验结果，大、小鼠经口ＬＤ５０分别为９２６Ｏｍｇ／ｋｇ和９...     

TX—1型净水剂的致突变性研究

ＴＸ—１型净水剂的致突变性研究刘沛玉，张月兰，蒋中仁（成都四川省卫生防疫站６１００３１）ＴＸ－１型净水剂是一种以泥煤、铝屑、盐酸等为主要原料而生成的一种金属络合物，样品呈棕黑色粘稠液体，一般毒性试验结果，大、小鼠经口ＬＤ５０分别为９２６Ｏｍｇ／ｋｇ和...     

中国传统加工食品致突变性的研究

选取烧烤和腌腊鱼肉、禽肉类制品、粉肠及调味品等十个具有代表性的中国传统加工食物样品,用乙醚和/或甲醇提取,再过XAD-2树脂柱,以Ames试验进行致突变性检测。其中有七种样品具有不同程度的致突变性,以烧烤肉类中的烤鸭皮及羊肉串的致突变性最为明显,均对TA98(+S9)呈阳性反应,具有剂量反应关系。烧烤时间长则突变性增强。在醃腊鱼肉制品中,四个样品全部有致突变反应。且作用于多个菌株(TA97、TA98、TA100、TA102)。对酿造制品酱油和鱼露及粉肠中未检出致突变性。 本研究提示中国部分传统食品在加工制作过程中所形成致突变物,烧烤肉类的致突变性可能主要与氨基酸热解产物有关。醃腊制品的致突变性可能与亚硝基化合物有关。     

标准化Ames波动试验最佳条件的优选

目的： 建立Ames波动试验的标准化方法,为其应用于化合物的遗传毒性检测奠定基础。方法：应用4种已知具有遗传毒性的阳性化合物敌克松(Dexon)、叠氮钠(SA)、环磷酰胺(CP)和2-氨基芴(2-AF)进行Ames波动试验。比较2种不同的增菌方法和2种指示剂,建立Ames波动试验的方法。Dexon采用0.1、1和10 μg/mL,SA采用0.01、0.1、1 μg/mL在非活化条件下与相应的溶剂对照进行试验;CP采用10、100、1 000 μg/mL,2-AF采用0.1、1和10 μg/mL在活化条件下与相应的溶剂对照进行试验;观察记录阳性孔数,根据情况调整阳性化合物的剂量,直到经统计分析后阳性孔数与溶剂对照组相比,差异有统计学意义(P<0.01)。确定各阳性化合物的剂量后,在相同剂量下重复试验3次,保证试验系统稳定可靠。结果：确定了Ames波动试验4种阳性化合物的剂量。在不加S9代谢活化系统的条件下,Dexon 3 μg/mL和SA 0.05 μg/mL,3块平行96孔板与溶剂对照组相比差异均有统计学意义(P<0.01),对TA100呈现出强致突变作用;在加入S9代谢活化系统的条件下,CP 100 μg/mL和2-AF 30 μg/mL,3块平行96孔板与溶剂对照组相比差异均有统计学意义(P<0.01),对TA100也呈现出强致突变作用。同时,在实验过程中改进了试验方法：包括对受试物剂量的标准化,改进了增菌培养的方法,并确定了指示剂。结论：建立了Ames波动试验方法,对已知阳性化合物测定结果的稳定性良好,并在研究中优化了实验条件。     

葡萄籽原花青素对鼠伤寒沙门氏菌的抗诱变作用

目的: 观察葡萄( V itis vinif era) 籽原花青素的抗诱变作用。方法:以S almonella typhimurium TA97 、TA98 、TA100 、TA102为标准试验菌株进行Ames 试验。结果:在不加S9 条件下,原花青素能显著抑制Dexon 诱发的TA97 、TA98回复突变,叠氮钠诱发的TA100回复突变,丝裂霉素C 诱发的TA102回复突变;在不加S9 条件下,原花青素能显著抑制2-氨基芴诱发的TA97 、TA98及TA100回复突变,而对1 ,8-二羟基蒽醌诱发的TA102回复突变抑制作用较强。结论:葡萄籽原花青素对多种化学诱变剂 有抗诱变作用。     

氯化消毒对自来水致突变性影响研究

本文通过鼠伤寒沙门氏菌致突变试验,分析常用氯化消毒方法对饮用水遗传毒性的影响。     

Response of the ke test to NCI/NTP-screened chemicals. I. Non-genotoxic carcinogens and genotoxic non-carcinogens

The response of a physico-chemical carcinogen-screening test, the k(e) test, to 46 rodent carcinogens and 20 putative non-carcinogens that had been screened in long-term two-species bioassays by the National Cancer Institute/National Toxicology Program are reported. All of the chemicals screened are those that yield mutagenicity responses in the Ames Salmonella/microsome test that are either equivocal or contrary to the rodent carcinogenicity responses. The electron attachment rate constants, k(e)S, of the test chemicals in cyclohexane at 21 degrees C were measured using a pulse-conductivity technique. The k(e)S of 27 of the 46 rodent carcinogens (59%) are equal or greater than the diffusion-controlled k(e) of carbon tetrachloride, which is regarded as the boundary between a positive and negative response; the k(e)S of 8 of the 20 mutagenic non-carcinogens (40%) are less than diffusion-controlled. If the boundary between positive and negative k(e) responses is decreased to half the diffusion-controlled k(e), six additional carcinogens yield a positive ke response which increases the k(e) test sensitivity to 72% while the specificity to non-carcinogens remains at 40%. Comparison of these k(e)S with measures of the chemicals' electrophilicity that had been inferred from chemical structure indicates that k(e) provides a markedly different measure of electrophilicity and one that complements the Ames Salmonella assay. The use of the k(e) test as an analytical tool to indicate the presence of electron-attaching impurities in solvents such as benzene is discussed, as is the sensitivity of the k(e) test to rodent-liver carcinogens.     

Ras激酶抑制子KSR定点突变、表达和鉴定

背景与目的 Ras to MAPK通路在生长、发育信号传递中起关键的作用。Ras激酶抑制基因（KSR）是该通路中的一个重要组分，其功能主要是作为一个支架蛋白协调装配包含有丝分裂原活化蛋白激酶（MAPK）及其上游调控子的多蛋白复合体。已有的研究表明KSR有许多磷酸化位点，这些位点磷酸化状态的改变与外界信号刺激有着极为密切的关系。利用定点突变技术可以准确地改变基因特定碱基序列，获得突变蛋白质。本研究的目的是应用定点突变技术构建突变型KSR，并将其瞬时转染293T细胞所表达蛋白纯化和鉴定，为进一步研究KSR生化作用机制提供理论和实验依据。方法 以本实验室自己构建的pCMV-Tag2b-KSR质粒为模板，应用本实验室改进的QuikChang^tm定点突变方法，引入KSR12个突变位点，构建突变型pCMV-Tag2b-KSR，并将其瞬时转染293T细胞进行蛋白表达，亲和胶纯化并经SDS-PAGE和蛋白质印迹鉴定。结果 成功构建了2个突变型KSR基因，经DNA序列分析突变碱基，证实位点正确，并经过瞬时转染293T细胞表达出突变体蛋白，纯化蛋白经SDS-PAGE和蛋白质印迹鉴定与实验设计完全一致。结论 成功构建了2个具有不同突变位点的突变型KSR，为以后进行蛋白功能研究提供实验基础。     

The morphological transformation of Syrian hamster embryo cells by chemicals reportedly nonmutagenic to Salmonella typhimurium

Nine chemicals classified as presumptive carcinogens on the basis of chronic rodent bioassays and one suspected human carcinogen which are reportedly not mutagenic to Salmonella typhimurium tester strains were tested for the ability to produce morphological transformation in Syrian hamster embryo cells in the absence of any exogenous source of metabolic activation. Acetamide, benzene, carbon tetrachloride, L-ethionine, monuron, piperonyl butoxide and trichloroethylene all induced positive morphological transformation in the presence of at least one of two medium and serum combinations as did the positive controls, ethyl methanesulfonate and benzo[a]pyrene. The remaining three chemicals, griseofulvin, isoniazid and trypan blue, did not induce morphological transformation under these same test conditions suggesting that they differ from the other seven chemicals in mechanism of action, target specificity or species susceptibility. Our results for seven of those ten selected chemicals in the clonal transformation assay using Syrian hamster embryo cells differ from their reported activity in the S. typhimurium point mutation assay. On the basis of this small sample, the Syrian hamster embryo transformation assay was a better predictor of the reported rodent bioassay results.     

The mutagenic response at the ouabain resistance locus in T cells of mice exposed to N-ethyl-N-nitrosourea parallels the response at the Hprt locus and correlates with mutation target size

The lymphocyte Hprt gene has been used extensively as a reporter locus to monitor the mutational effects of the exposure of animals to genotoxicants. Implicit in this view of the function of a reporter gene is the assumption that its mutagenic response is representative of that of other genes in the organism. As a test of this hypothesis we compared the frequency of 6-thioguanine-resistant (TGr) mutants at the Hprt locus with the mutant frequency (MF) induced at another locus, the ouabain resistance (Oua) locus. The frequency of spontaneous OUA(R) mutants was estimated to be 1.1x10(-7) (MF between <0.3 and 1.1x10(- 7)), which was approximately 30-fold less than the spontaneous TGr MF. Following treatment with N-ethyl-N-nitrosourea (ENU), the induced OUA(R) MF at each of two dose levels (50 and 150 mg/kg ENU) and two time points (3 and 6 weeks post-exposure) was consistently 8- to 9-fold lower than the corresponding TGr MF. Thus the mutagenic response of the Oua locus closely paralleled that of the Hprt locus, indicating a similarity in their response to ENU. In addition, the Oua locus was 3-4 times more sensitive than the Hprt locus to the mutagenic effect of ENU, as measured by the fold increase in MF over the background level. The number of ENU-mutable sites capable of resulting in a TGr or OUA(R) phenotype, otherwise known as the mutation target size, was estimated to differ by an order of magnitude between the two loci. This difference in target size correlates with, and therefore may largely account for, the difference in induced MF between both loci.      

Bovine bladder urothelial cell activation of carcinogens to metabolites mutagenic to Chinese hamster V79 cells and Salmonella typhimurium

The ability of bovine bladder urothelial cells to activate genotoxic chemicals to mutagens was examined by cocultivating bladder cells with Chinese hamster V79 cells or Salmonella typhimurium as mutable targets. Activation of test chemicals to mutagenic intermediates by urothelial cells was detected by induction of 6-thioguanine resistance in V79 cells or by induction of histidine revertants in Salmonella. In the bladder cell-mediated V79 cell mutagenesis system, a significant increase in mutation frequency was induced by exposure to 7,12-dimethylbenz(a)anthracene and dimethylnitrosamine. The aromatic amines 2-aminofluorene, 2-acetylaminofluorene, and 4-aminobiphenyl were weakly mutagenic to V79 cells with bladder cell activation, while no mutagenic activity was detected with 1-naphthylamine, 2-naphthylamine, or benzidine. Because the mutagenic activity of the aromatic amines was low with V79 cells as the target, a bladder cell-mediated S. typhimurium system was developed for these chemicals. The aromatic amines 2-aminofluorene, 2-acetylaminofluorene, 4-aminobiphenyl and 2-naphthylamine were mutagenic to S. typhimurium TA98 and TA100 in the presence of bladder cells but not in their absence. Benzidine was mutagenic to TA98 but not to TA100. The putative noncarcinogen 1-naphthylamine was not mutagenic in the system. In contrast to the V79 data, 7,12-dimethylbenz(a)anthracene and dimethylnitrosamine were not mutagenic with either bacterial strain. Mutagenic responses were related to both the number of bladder cells used for activation and the concentration of test chemical in the Salmonella assay. The data demonstrate that bovine bladder urothelial cells can activate carcinogens from three chemical classes to mutagens and indicate the different sensitivities of V79 cells and S. typhimurium to genotoxic agents.     

Biomarkers of exposure and effect as indicators of potential carcinogenic risk arising from in vivo metabolism of ethylene to ethylene oxide

The purposes of the present study were: (i) to investigate the potential use of several biomarkers as quantitative indicators of the in vivo conversion of ethylene (ET) to ethylene oxide (EO); (ii) to produce molecular dosimetry data that might improve assessment of human risk from exogenous ET exposures. Groups (n = 7/group) of male F344 rats and B6C3F1 mice were exposed by inhalation to 0 and 3000 p. p.m. ET for 1, 2 or 4 weeks (6 h/day, 5 days/week) or to 0, 40, 1000 and 3000 p.p.m. ET for 4 weeks. N:-(2-hydroxyethyl)valine (HEV), N:7-(2-hydroxyethyl) guanine (N7-HEG) and HPRT: mutant frequencies were assessed as potential biomarkers for determining the molecular dose of EO resulting from exogenous ET exposures of rats and mice, compared with background biomarker values. N7-HEG was quantified by gas chromatography coupled with high resolution mass spectrometry (GC-HRMS), HEV was determined by Edman degradation and GC-HRMS and HPRT: mutant frequencies were measured by the T cell cloning assay. N7-HEG accumulated in DNA with repeated exposure of rodents to 3000 p.p.m. ET, reaching steady-state concentrations around 1 week of exposure in most tissues evaluated (brain, liver, lung and spleen). The dose-response curves for N7-HEG and HEV were supralinear in exposed rats and mice, indicating that metabolic activation of ET was saturated at exposures >/=1000 p.p.m. ET. Exposures of mice and rats to 200 p.p.m. EO for 4 weeks (as positive treatment controls) led to significant increases in HPRT: mutant frequencies over background in splenic T cells from exposed rats and mice, however, no significant mutagenic response was observed in the HPRT: gene of ET-exposed animals. Comparisons between the biomarker data for both unexposed and ET-exposed animals, the dose-response curves for the same biomarkers in EO-exposed rats and mice and the results of the rodent carcinogenicity studies of ET and EO suggest that too little EO arises from exogenous ET exposure to produce a significant mutagenic response or a carcinogenic response under standard bioassay conditions.     

Assay of 855 test chemicals in ten tester strains using a new modification of the Ames test for bacterial mutagens.

Determination of mutagenic activity in bacterial systems has become accepted as an initial step in the evaluation of the carcinogenic potential of new chemicals. In this paper, a bacterial mutagen screening technique is described in which chemicals can be tested in 10 tester strains over a 10,000-fold concentration gradient both with and without metabolic activation. Using this assay, 855 chemicals were tested, and 182 were found to be mutagenic in one or more of the tester strains. Included were 299 chemicals used in chemical manufacturing or laboratory synthesis. Of these, 20% gave a positive response in one or more strains. The high rate of positives undoubtedly reflects the high chemical reactivity of compounds in this group. In contrast, when 261 organic chemicals which were synthesized for evaluation as potential pharmaceutical or agricultural products were tested, only 8% were identified as mutagenic. The Salmonella typhimurium tester strains TA98 and TA1538 proved to be very reliable and efficient in detecting and identifying frame-shift mutagens. TA100 was the most sensitive tester strain, detecting 142 of the 182 mutagens encountered in the study. However, since TA100 detected both base substitution mutagens and frame-shift mutagens, this tester strain was not suitable for the specific identification of base substitution mutagens. Base substitution mutagens were more reliably detected by Escherichia coli tester strains WP2 and WP2 uvrA- than they were by S. typhimurium strains G46 and TA1535. The data obtained when mutagens are tested by the concentration gradient procedures can include (a) the activity spectrum in tester strains, (b) identification as either frame-shift or base substitution mutagens, (c) the minimal concentration at which auxotroph growth is inhibited, and (d) mutagenic potency in terms of minimal concentration at which mutagenicity is observed. The data obtained have been found to be of immediate use. For example, with manufacturing intermediates the data have been combined with other toxicity data and used as a basis for setting safety standards for handling such compounds in the workplace. In addition, positive bacterial mutagenicity data on selected members of new series of organic compounds can serve to alert the chemist early to the possibility that the compounds may possess undesirable toxic properties, particularly carcinogenicity. Also, this type of data should be of great value both in the planning and in the interpretation of other in vitro tests designed to evaluate the potential carcinogenicity in mammals of chemicals found to be positive in bacterial tests.     

In vitro mutagenicity assays of chemical carcinogens and related compounds with Salmonella typhimurium.

The mutagenic activity of 101 chemicals was studied with the use of the Salmonella typhimurium-microsome system described by Ames. The tester strains were TA1535, TA1536, TA1537, TA1538, TA98, and TA100. Assays were conducted in the presence and absence of a metabolic activation system prepared from the livers of randomly bred Sprague-Dawley rats that had been pretreated with Aroclor 1254. The test chemicals were incorporated into the agar with bacteria and the metabolic activation system. Mutagens were defined as chemicals that induced a reproducible dose-related increase in the number of histidine-independent revertants. With the use of these procedures, 65% of the organic carcinogens and 25% of the noncarcinogens were found to be mutagenic.