Ames试验在水质检测方面的应用

近年来 ,水体污染日趋严重 ,各国学者从氯化后饮水中分离出多种致突变、致癌物质。为此我们采用Ames试验 ,对珠江流域主要取水点的水源水和对应自来水中的有机致突变物污染情况进行了研究。研究表明 ,部分取水点的有机致突变物污染较严重 ,并且氯化消毒后自来水的致突性大于水源水的致突性。因而 ,加强饮水中致突变物质的检测 ,改进净水消毒剂和净水流程很有必要。     

微核检测技术的应用--中学生物学课外活动的好题材

微核检测技术是一项非常有效而实用的实验技术,常被用于进行环境监测分析。它是一种在世界范围内广泛推广运用的环境致突变性检测技术,同时也是我国水环境生物测试的规范方法,可以用于检测水体的致突变性。在中学生物学的课外活动中,结合绿色奥运等项活动,利用微核检测技术研究各种因素对生物体的影响作用,是一个非常可行而有意义的活动。     

抚仙湖无机污染物化学背景值及动物体内致突变性评定

为了比较抚仙湖不同区域的水质及其致突变性,从抚仙湖周围水域采取７个样点的水样。用电感耦合氩等离子发射光谱法对水样中的无机污染物作定性和定量分析,另外使用蝌蚪红细胞微核试验检测抚仙湖水样的致突变性,结果显示：禄要样点水样带有微核的红细胞率增高,表明这个点水样有致突变活性物质。     

三种石黄衣的共生菌化学多样性及其系统生物学意义

本文对丽石黄衣(Xanthoria elegans)、中国石黄衣(X. mandschurica)和刺盘石黄衣(X. alfredi)的共生菌,尤其是刺盘石黄衣共生菌的分离培养物进行了首次研究。对于上述三种地衣体及其共生菌的化学物质进行了比较分析。研究与分析结果表明,三种石黄衣地衣体化学物质,即蒽醌类化合物完全一致。此外, Lindblom从15种北美石黄衣地衣体中检测出了彼此一致的5种蒽醌类化合物。因此,该作者认为石黄衣属的蒽醌类化合物不具有种级分类学意义。本文的实验结果也证实了这一观点。但是,本文对于通过子囊孢子释放法获得的中国三种石黄衣共生菌的化学物质进行了检测和分析,其结果呈现出比较丰富的多样性。其中刺盘石黄衣共生菌化学物质与丽石黄衣和中国石黄衣共生菌所含的化学物质存在明显差异。因而,刺盘石黄衣共生菌化学物质在该种地衣的鉴定中具有重要的参考价值。 此外,文章亦检测和分析了丽石黄衣的10株共生菌化学物质。供试菌株均在相同培养条件和培养时间下获得。其化学物质的TLC图谱,除Nos. 5, 7, 及10稍有差异外,几乎完全一致。由此看来,它们稳定性也是比较明显的。 上述结果提示我们,在地衣系统生物学研究中,除了对于地衣体化学物质进行常规检测与分析之外,对于分离培养的各种地衣共生真菌化学物质的检测与分     

水体污染物"三致"效应的生物监测研究进展

由于大量且多种多样化学物质进入到水环境中 ,使得水体不同程度地表现出致突变性、致癌性、致畸性。传统分析技术与综合指标不能客观、及时反映水的这种特性。而短期生物试验以其具有快速的、综合的响应水中这方面变化的特点 ,越来越受到重视与应用。本文主要论述与评价“三致”物作用机理以及几种常用短期生物试验 (Ames试验、微核试验、非程序DNA合成、SOS显色试验、姊妹单体交换测定、单细胞凝胶电泳技术 )。并分类评述了可用于此领域的生物材料的来源、特性 ,便于同类科研工作参考     

用CHO细胞进行SCE检验方法探索

以姐妹染色单体交换(sister chromatid exchange,SCE)为指标,是继微核检测之后对各种化学物质的遗传毒性做进一步研究的有效方法。通过对化学物质进行SCE的数据统计,可以在一定程度上反映其致突变作用,是遗传毒性的敏感指标。试验中,应用CHO细胞株为主要材料,建立了以体外培养细胞SCE试验方法。在CHO细胞SCE试验中,在正式制片处理前3～4h加入秋水仙素;细胞通过65～70min低渗;第3次固定甲醇-冰乙酸比例为1：2;在加入5-溴脱氧尿嘧啶(BUda)后1～1．5个细胞周期后对细胞进行收获能取到最佳制片效果,得到良好的检测效果。     

环氧树脂618和Epon812引起鼠伤寒沙门氏菌株细胞突变的超微结构研究

电镜实验室常用包埋剂环氧树脂618和Epon 812经Ames检测试验,表明两者均为直接致突变剂,它们的致突变性是同一数量级。超微结构观察提示,回变株细胞核区结构发生变异可能是受试环氧树脂烷化作用的结果。对于致突变试验阳性的电镜包埋剂应视为潜在的致癌剂而加以防范。     

文蛤肉水解液的致突变性

目的评价文蛤肉水解液的致突变性,为文蛤的开发利用提供实验数据。方法采用Ames试验、小鼠嗜多染红细胞骨髓微核试验和CHL细胞体外染色体畸变试验3项致突变性试验,检测文蛤肉水解液有无致突变作用。结果 Ames试验中文蛤肉水解液各剂量组回变菌落数均在正常范围内,均未超过自发回变菌落数的2倍,在加与不加S9时5株试验菌株结果为阴性。CHL细胞体外染色体畸变试验,文蛤肉水解液各剂量组的染色体畸变率与阴性对照组比较,差异无显著性(P0.05),结果为阴性。小鼠骨髓微核试验,各剂量组的微核率与阴性对照组比较,差异无显著性(P0.05),结果为阴性。结论在本试验条件和范围下,文蛤肉水解液未见潜在的致突变作用。     

四种品系小鼠在微核试验中诱发微核的敏感性比较

微核试验现已广泛用于检测化学物质的遗传毒性和潜在致癌性。该试验筛选致突变原具有简单、快速和经济的优点,但由于它具有一定的局限性,故近年来毒理学家又致力于敏感动物和靶器官的寻找。本文试图从目前国内常用的小鼠品系中寻找对微核试验敏感的动物,以提高微核试验对致突变原的检出率。材料和方法动物:由华西医科大学提供远交系小鼠NIH、近交系小鼠615和BALB/C以及非纯系昆明种小鼠各12只,体重20～25克,鼠龄2～3月,雌雄各半。药物:医用环磷酰胺(上海第十二制药厂生产)为实验组诱发剂,临用前用生理盐水配成10mg/1ml。方法:实验基本按…     

三种石黄衣的共生菌化学多样性及其系统生物学意义

本文对丽石黄衣(Xanthoria elegans)、中国石黄衣(X.mandschurica)和刺盘石黄衣(X.alfredi)的共生菌,尤其是刺盘石黄衣共生菌的分离培养物进行了首次研究。对于上述三种地衣体及其共生菌的化学物质进行了比较分析。研究与分析结果表明,三种石黄衣地衣体化学物质,即蒽醌类化合物完全一致。此外,Lindblom从15种北美石黄衣地衣体中检测出了彼此一致的5种葸醌类化合物。因此,该作者认为石黄衣属的蒽醌类化合物不具有种级分类学意义。本文的实验结果也证实了这一观点。但是,本文对于通过子囊孢子释放法获得的中国三种石黄衣共生菌的化学物质进行了检测和分析,其结果呈现出比较丰富的多样性。其中刺盘石黄衣共生菌化学物质与丽石黄衣和中国石黄衣共生菌所含的化学物质存在明显差异。因而,刺盘石黄衣共生菌化学物质在该种地衣的鉴定中具有重要的参考价值。此外,文章亦检测和分析了丽石黄衣的10株共生菌化学物质。供试菌株均在相同培养条件和培养时间下获得。其化学物质的TLC图谱,除Nos．5,7,及10稍有差异外,几乎完全一致。由此看来,它们稳定性也是比较明显的。上述结果提示我们,在地衣系统生物学研究中,除了对于地衣体化学物质进行常规检测与分析之外,对于分离培养的各种地衣共生真菌化学物质的检测与分析也是必不可少的。因为,地衣系统生物学归根结底是地衣型真菌的系统生物学。在上述三种石黄衣共生菌化学物质以及其地衣体化学物质的比较研究中,并未发现丽石黄衣和中国石黄衣之间的明显差异。因此,有理由怀疑,这两种地衣究竟是不同的物种,抑或是同一物种的多态型？对此,我们将在今后研究中作进一步探讨。     

Analysis of mutagenic activity of airborne particulate matter, standard reference materials and reference compounds using base pair-specific Salmonella typhimurium tester strains

The mutagenicity profiles of organic extracts of airborne dust samples from Mannheim, Germany, and two standard reference materials (SRM) as well as eight compounds with different chemical properties were investigated using tester strains Salmonella typhimurium TA700x (Ames II Assay). Each strain of this series carries a unique missense mutation in the histidine operon and is reverted by only one specific base substitution out of six possible changes. Mutation patterns of eight compounds with different modes of genotoxic action reveal significant differences. Samples of airborne particulate matter (APM) from an industrialized town in Germany (Mannheim) were collected for five consecutive days once a month for 1 year using an automatic high-volume air sampler. Samples taken from Monday to Friday were Soxhlet-extracted and prepared according to standard methods. Although the threshold limit for the least active strains is not triggered by all samples, it can be concluded that mutation patterns of the samples do not vary between different seasons. Standard reference materials (SRMs) were prepared and tested using the same methods. SRMs and APM samples from Mannheim reveal similar mutagenicity profiles in TA700x strains. The comparison of the mutagenicity profiles of air dust extracts from Mannheim and the SRMs, respectively, with reference compounds investigated so far shows some similarities although the patterns do not fit perfectly. Mutagenicity profiles of TA700x-activity of nitro-aromatic compounds published so far are similar to those of APM collected in Mannheim, Germany, as well as to standard reference materials 1648 and 1649.     

Strategies and testing methods for identifying mutagenic risks

The evolution of testing strategies and methods for identification of mutagenic agents is discussed, beginning with the concern over potential health and population effects of chemical mutagens in the late 1940s that led to the development of regulatory guidelines for mutagenicity testing in the 1970s and 1980s. Efforts to achieve international harmonization of mutagenicity testing guidelines are summarized, and current issues and needs in the field are discussed, including the need for quantitative methods of mutagenic risk assessment, dose-response thresholds, indirect mechanisms of mutagenicity, and the predictivity of mutagenicity assays for carcinogenicity in vivo. Speculation is offered about the future of mutagenicity testing, including possible near-term changes in standard test batteries and the longer-term roles of expression profiling of damage-response genes, in vivo mutagenicity testing methods, and models that better account for differences in metabolism between humans and laboratory model systems.     

Quantification of a potent mutagenic 4-amino-3,3'-dichloro-5,4'-dinitrobiphenyl (ADDB) and the related chemicals in water from the Waka River in Wakayama, Japan

4-Amino-3,3'-dichloro-5,4'-dinitrobiphenyl (ADDB) is a novel chemical exerting strong mutagenicity, especially in the absence of metabolic activation. In addition to mutagenicity, ADDB may also disrupt the endocrine system in vitro. ADDB may be discharged from chemical plants near the Waka River and could be unintentionally formed via post-emission modification of drainage water containing 3,3'-dichlorobenzidine (DCB), which is a precursor in the manufacture of polymers and dye intermediates in chemical plants. The main purpose of this study was to make a comprehensive survey of the behaviour and levels of ADDB and suspected starting material or intermediates of ADDB, i.e., DCB, 3,3'-dichloro-4,4'-dinitrobiphenyl (DDB), and 4-amino-3,3'-dichloro-4'-nitrobipheny (ADNB) in Waka River water samples. We also postulated the formation pathway of ADDB. Water samples were collected at five sampling sites from the Waka River four times between March 2003 and December 2004. Samples were passed through Supelpak2 columns, and adsorbed materials were then extracted with methanol. Extracts were used for quantification of ADDB and the related chemicals by HPLC on reverse-phase columns; mutagenicity was evaluated in the Salmonella assay using the O-acetyltransferase-overexpressing strain YG1024. High levels of ADDB, DCB, DDB, and ADNB (12.0, 20,400, 134.8, and 149.4ng/L-equivalent) were detected in the samples collected at the site where wastewater was discharged from chemical plants into the river. These water samples also showed stronger mutagenicity in YG1024 both with and without S9 mix than the other water samples collected from upstream and downstream sites. The results suggest that ADDB is unintentionally formed from DCB via ADNB in the process of wastewater treatment of drainage water containing DCB from chemical plants.     

Considerations in the U.S. Environmental Protection Agency's testing approach for mutagenicity.

OPP: This paper provides the rationale and support for the decisions the OPP will make in requiring and reviewing mutagenicity information. The regulatory requirement for mutagenicity testing to support a pesticide registration is found in the 40 CFR Part 158. The guidance as to the specific mutagenicity testing to be performed is found in the OPP's Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals (referred to as the Subdivision F guideline). A revised Subdivision F guideline has been presented that becomes the current guidance for submitters of mutagenicity data to the OPP. The decision to revise the guideline was the result of close examination of the version published in 1982 and the desire to update the guidance based on developments since then and current state-of-the-science. After undergoing Agency and public scrutiny, the revised guideline is to be published in 1991. The revised guideline consists of an initial battery of tests (the Salmonella assay, an in vitro mammalian gene mutation assay and an in vivo cytogenetics assay which may be either a bone marrow assay for chromosomal aberrations or for micronuclei formation) that should provide an adequate initial assessment of the potential mutagenicity of a chemical. Follow-up testing to clarify results from the initial testing may be necessary. After this information as well as all other relevant information is obtained, a weight-of-evidence decision will be made about the possible mutagenicity concern a chemical may present. Testing to pursue qualitative and/or quantitative evidence for assessing heritable risk in relation to human beings will then be considered if a mutagenicity concern exists. This testing may range from tests for evidence of gonadal exposure to dominant lethal testing to quantitative tests such as the specific locus and heritable translocation assays. The mutagenicity assessment will be performed in accordance with the Agency's Mutagenicity Risk Assessment Guidelines. The mutagenicity data would also be used in the weight-of-evidence consideration for the potential carcinogenicity of a chemical in accordance with the Agency's Carcinogen Risk Assessment Guidelines. In instances where there are triggers for carcinogenicity testing, mutagenicity data may be used as one of the triggers after a consideration of available information. It is felt that the revised Subdivision F guideline will provide appropriate, and more specific, guidance concerning the OPP approach to mutagenicity testing for the registration of a pesticide. It also provides a clearer understanding of how the OPP will proceed with its evaluation and decision making concerning the potential heritable effects of a test chemical.(ABSTRACT TRUNCATED AT 400 WORDS)     

Quantification of a potent mutagenic 4-amino-3,3′-dichloro-5,4′-dinitrobiphenyl (ADDB) and the related chemicals in water from the Waka River in Wakayama, Japan

4-Amino-3,3′-dichloro-5,4′-dinitrobiphenyl (ADDB) is a novel chemical exerting strong mutagenicity, especially in the absence of metabolic activation. In addition to mutagenicity, ADDB may also disrupt the endocrine system in vitro. ADDB may be discharged from chemical plants near the Waka River and could be unintentionally formed via post-emission modification of drainage water containing 3,3′-dichlorobenzidine (DCB), which is a precursor in the manufacture of polymers and dye intermediates in chemical plants. The main purpose of this study was to make a comprehensive survey of the behaviour and levels of ADDB and suspected starting material or intermediates of ADDB, i.e., DCB, 3,3′-dichloro-4,4′-dinitrobiphenyl (DDB), and 4-amino-3,3′-dichloro-4′-nitrobipheny (ADNB) in Waka River water samples. We also postulated the formation pathway of ADDB. Water samples were collected at five sampling sites from the Waka River four times between March 2003 and December 2004. Samples were passed through Supelpak2 columns, and adsorbed materials were then extracted with methanol. Extracts were used for quantification of ADDB and the related chemicals by HPLC on reverse-phase columns; mutagenicity was evaluated in the Salmonella assay using the O-acetyltransferase-overexpressing strain YG1024. High levels of ADDB, DCB, DDB, and ADNB (12.0, 20,400, 134.8, and 149.4 ng/L-equivalent) were detected in the samples collected at the site where wastewater was discharged from chemical plants into the river. These water samples also showed stronger mutagenicity in YG1024 both with and without S9 mix than the other water samples collected from upstream and downstream sites. The results suggest that ADDB is unintentionally formed from DCB via ADNB in the process of wastewater treatment of drainage water containing DCB from chemical plants.     

Development of new structural alerts suitable for chemical category formation for assigning covalent and non-covalent mechanisms relevant to DNA binding

The need to assess the ability of a chemical to act as a mutagen is one of the primary requirements in regulatory toxicology. Several pieces of legislation have led to an increased interest in the use of in silico methods, specifically the formation of chemical categories and read-across for the assessment of toxicological endpoints. One of the key steps in the development of chemical categories for mutagenicity is defining the mechanistic organic chemistry associated with the formation of a covalent bond between DNA and an exogenous chemical. To this end this study has analysed, by use of a large set of mutagenicity data (Ames test), the mechanistic coverage of a recently published set of in silico structural alerts developed for category formation. The results show that the majority of chemicals with a positive result in the Ames test were assigned at least one covalent binding mechanism related to the formation of a DNA adduct. The remaining chemicals with positive data in the Ames assay were subjected to a detailed mechanistic analysis from which 26 new structural alerts relating to covalent binding mechanisms were developed. In addition, structural alerts for radical and non-covalent intercalation mechanisms were also defined. The structural alerts outlined in this study are not intended to predict mutagenicity but rather to identify mechanisms associated with covalent and non-covalent DNA binding. This mechanistic profiling information can then be used to form chemical categories suitable for filling data gaps via read-across. A strategy for chemical category formation for mutagenicity is also presented.     

The Salmonella mutagenicity test: evaluation of 29 drug candidates

The Salmonella mutagenicity test (Ames assay) is part of the routine screening battery applied to all new drugs at The Upjohn Company. The purpose of this paper is to report results for 29 compounds. These compounds are very diverse in chemical structure and represent classes of compounds selected because of known biological activity and other reasons. None of the compounds reported here produced an increase in revertant colonies in the Salmonella strains employed (TA98, TA100, TA1535, TA1537 and TA1538) and therefore the Salmonella mutagenicity results with these materials do not suggest potential for mutagenesis or carcinogenesis.     

Methods for analysis of the mutagenicity of indirect mutagens/carcinogens in eukaryotic cells

Summary The review discusses the variety of methods for activation of indirect mutagens/carcinogens and testing them in cell cultures, especially in mammalian cell cultures.After the necessity for including metabolizing components in mutagenicity tests has been pointed out, the enzymes that transform foreign compounds metabolically, and the factors influencing them, are described. In the main section the various methods of activating indirect mutagens/carcinogens are presented. The methods of including in vivo metabolism in mutagenicity tests are: Analysis of cells from organisms contaminated with a chemical (III.1.a); body fluid-mediated mutagenesis (III.1.b); host-mediated assay (III.1.c).The following activation systems are suitable for including in vitro metabolism of test compounds in mutagenicity tests: Liver and lung perfusion (III.2.a.); organ slices and homogenates (III.2.a.); subcellular fractions (III.2.a.); cultivated cells (cell-mediated mutagenesis) (III.2.b); nonenzymatic activation systems (III.2.c).Finally the main factors that influence the metabolism of test substances are summarized. Two figures illustrate the mutagenicity tests with regard to the metabolism of mammalian livers and the methods of performing mutagenicity tests in man.     

On the reaction kinetics in water of 1,3-propane sultone and 1,4-butane sultone: a comparison of reaction rates and mutagenic activities of some alkylating agents.

To determine correlations between the biological action pattern and chemical reactivity of alkylating agents, the rate constants for reactions of 1,3-propane sultone and 1,4-butane sultone with a series of nucleophiles at 37 degrees C have been determined. Previously published data on the mutagenicity of the two sultones and of some alkyl methanesulfonates and dialkyl sulfates towards Schizosaccharomyces pombe have been used in the evaluation of the dependence of mutagenic effectiveness on chemical reactivity. It is of interest to note that the mutagenic effectiveness of the two sultones, if expressed per alkylating event at a certain low nucleophilicity is the same as that of e.g. methyl methanesulfonate and ethyl methanesulfonate.     

Methods for the spiral Salmonella mutagenicity assay including specialized applications

An automated approach to bacterial mutagenicity testing - the spiral Salmonella assay - was developed to simplify testing and to reduce the labor and materials required to generate dose-responsive mutagenicity information. This document provides the reader with an overview of the spiral assay and a discussion of its application for examining the mutagenic potential of pure compounds, complex environmental mixtures, and interactive effects. Guidelines for performing a routine spiral assay are presented, and alternative test methods intended to overcome a variety of technical difficulties (such as restricted sample availability, sample viscosity or volatility, etc.) are recommended. Methods for the computerized analysis of data and the interpretation of results are discussed.