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1.
本文利用青蛙(Rana nigromaculata Hallowell)蝌蚪红细胞微核试验,作为检测城镇污水诱变活性的一种新的监测技术。在16d生活污水处理的实验中,青蛙蝌蚪红细胞微核细胞率2d后就呈现统计上的显著增加,并随处理时间的延长而增高,第12d达到最大值。在不同浓度混合污水处理实验中,蝌蚪红细胞微核细胞率呈现明显的剂量依赖性增加。上述实验证明城镇生活污水和混合污水都具有较强的诱变活性。作者从遗传毒理学的角度评价了湖北黄州综合生物塘系统对污水诱变活性的净化效能。城镇混合污水经综合生物塘各级塘处理,蝌蚪微核细胞率逐级下降,由进水的7.54‰下降到最后出水的1.52‰,接近对照(1.07‰)水平。其中综合生物塘的藻菌单元比水生植物单元对污水诱变活性具有更强的净化效力。本文提出污水“诱变指数”可作为综合生物塘一项功能评价指标。  相似文献   

2.
应用青蛙红细胞微核试验和单细胞凝胶电泳试验研究了两种新型杀虫剂 -吡虫啉和抑食肼对青蛙蝌蚪和成体的遗传毒性 ,结果表明 :当吡虫啉为 2mg/L时 ,蝌蚪红细胞微核率与对照组相比 ,无显著性差异 (p >0 .0 5) ;浓度升高到 8mg/L时 ,微核率与对照组相比 ,有显著性差异 (p <0 .0 5) ;当浓度为 3 2mg/L时 ,微核率与对照组相比 ,有极显著性差异 (p <0 .0 1) ;并有明显的剂量 -效应关系 (r =0 .9843 )。而抑食肼在浓度为 2 .5mg/L和 10mg/L时 ,微核率与对照组相比 ,无显著性差异 (p >0 .0 5) ;当浓度增至 40mg/L时 ,微核与对照组相比 ,有极显著性差异 (p <0 .0 1) ;吡虫啉与抑食肼各浓度组对青蛙红细胞的DNA损伤与阴性对照组相比 ,都有极显著性差异 (p <0 .0 1) ,且具有明显的剂量 -效应关系 (r =0 .960 ,r=0 .990 )。  相似文献   

3.
核转移技术与克隆羊屈南平综述汪开圣郭求真审校(北京护士学校,101100)1背景无性繁殖动物后代的实验最早取得成功是剑桥大学Grudon领导的一个小组,早在七十年代,他们用蝌蚪各种组织及成年青蛙表皮细胞与去核的卵融合,结果产生了蝌蚪,但这些蝌蚪未能成...  相似文献   

4.
以花背蟾蜍蝌蚪外周血红细胞微核及核异常作为毒理监测指标,对Gosner 31、42和46期蝌蚪进行观察,研究了复合肥对水生生物的毒性效应.结果表明:用复合肥溶液浓度为1、1.5、2、2.5和3g·L-1进行染毒时,红细胞出现了大、小2种类型的微核,在核异常类型中出现了严重的核分叶和双核类型;在3个被观察的蝌蚪发育期中,42期蝌蚪红细胞微核细胞率和核异常细胞率数值明显低于其他两个发育期;在5个浓度的染毒中,2.5g·L-1浓度组在微核、双核和核分叶与对照组间无显著性差异;花背蟾蜍不同发育时期的蝌蚪,对生境中不良因素的抵抗能力存在着明显的差别,且微核和核异常与复合肥浓度之间没有明显的剂量-效应关系.  相似文献   

5.
本文使用蝌蚪红细胞微核率作为指示器研究明通河污水和用污水土地处理系统处理后水质的致突变性。蝌蚪在各种水样品中暴露7天。采心脏血制片。在对照组中,微核率分别为4.40‰和4.68‰。1/4明通河污水组诱发蝌蚪的微核率是17.01‰。同对照组相比有明显的差异。  相似文献   

6.
向日葵是观察生殖核(雄配子)的好材料   总被引:2,自引:0,他引:2  
向日葵(Helianthus annuns)的小孢子是具三细胞(核)的小孢子体(花粉),2个生殖核(细胞)细而长,1个营养核呈椭圆形,三核同时存在的时间长,容易区分,是观察三核小孢子体的一种好材料。  相似文献   

7.
为从不同遗传终点检测苯胺对黑斑蛙(Rana nigromaculata)蝌蚪红细胞的遗传毒性,将黑斑蛙蝌蚪暴露于0、3.45、17.26、34.53、69.06μg/L不同浓度的苯胺96 h后,显微镜下观察红细胞形态和数目的变化,采用微核试验测定红细胞微核率,通过彗星试验测定彗星尾长和尾距的变化。从17.26μg/L浓度组开始出现红细胞变形拉长和细胞膜破裂,且随着苯胺浓度的增加而增多。另外,各浓度组蝌蚪红细胞数目随着苯胺溶液浓度的增加而逐渐减少,且与空白对照相比差异显著(P0.01)。微核试验结果显示,各浓度处理组微核率均显著高于空白对照组(P0.05),但由于苯胺所致的红细胞破裂和Heinz小体的影响,微核率和浓度之间并未出现明显的浓度-效应关系。彗星试验结果显示,不同浓度苯胺处理组与空白对照组相比,蝌蚪红细胞尾长和尾距均显著增加(P0.05或P0.01),并与处理浓度之间存在显著的浓度-效应关系。上述结果表明,苯胺可诱发黑斑蛙蝌蚪红细胞的染色体、DNA损伤,具有较强的遗传毒性效应;苯胺最高浓度处理组69.06μg/L蝌蚪红细胞DNA损伤水平与5 mg/L环磷酰胺相近,显现明显的DNA损伤,因此建议渔业水质标准对水体中苯胺限量的规定不应高于此值。  相似文献   

8.
人工眼球     
由日本东京大学生物学教授MakotoAsashima带领的一个科研小组成功地培养出人工眼球 ,这在全世界还是首次。由于人类的身体组织构成基础与青蛙相同 ,所以研究人员成功地使用从青蛙胚胎中取出的细胞在蝌蚪上培养出了眼球 ,因此未来可望能藉此技术协助人恢复视力。在将胚胎中取出的细胞浸泡在一种特别的溶液后 ,研究人员将培养出的眼球移植入一只蝌蚪上 ,该蝌蚪在孵化时左眼就已经被移除。移植一周后 ,研究人员确认 ,蝌蚪的眼球已连络到视觉神经上 ,而且没有任何排斥症状出现人工眼球  相似文献   

9.
蝌蚪是青蛙的幼体,它是由青蛙的受精卵经4~5d的发育而形成的。蝌蚪在水中生活,主要吃植物性食物。蝌蚪生长到一定程度,即开始变态。在变态期,内、外部各器官由适应水栖转变为适应陆栖生活。在外观上.尾部逐渐萎缩,最后趋于消失,成对的附肢代替了鳍。由孵化出蝌蚪到变态完成,形成成体幼蛙,大约需时3个月左右。幼体蝌蚪变为成体青蛙的变态过程包括了许多重要的生理和基因调控的变化。  相似文献   

10.
隋御  李元杰  金彩霞  徐方 《遗传》2010,32(5):467-472
利用RNA干扰技术降低REV3基因在人类结肠癌细胞(SW480)中的表达, 以荧光实时定量PCR检测REV3表达量的降低情况, 选择低表达效率具有统计学意义的细胞作为实验组细胞。运用细胞生长曲线、MTT、微核和姐妹染色单体交换等方法, 对实验组和对照组细胞进行细胞生长周期、增殖变化情况和遗传信息表达等指标的检测。结果显示: REV3低表达的结肠癌实验组细胞在细胞增殖以及细胞的微核和姐妹染色单体交换等遗传信息表达均明显低于结肠癌对照组细胞, 实验结果具有统计学意义(P<0.05); 结肠癌的两对照组间(阴性和空白)的结果虽然有一定的差异, 但没有统计学意义。研究结果提示, REV3低表达时, 可能对结肠癌细胞(SW480)的生长与增殖产生影响, 并对微核和姐妹染色单体交换等遗传不稳定现象的产生有一定的抑制作用。  相似文献   

11.
Strain IC203, deficient in OxyR, and its oxyR(+) parent WP2 uvrA/pKM101 (denoted IC188) are the basis of a new bacterial reversion assay, the WP2 Mutoxitest, which has been used in the evaluation of 80 chemicals for oxidative mutagenicity. The following 31 oxidative mutagens were recognized by their greater mutagenic response in IC203 than in IC188: (1) peroxides: hydrogen peroxide (HP), t-butyl hydroperoxide (BOOH) and cumene hydroperoxide (COOH); (2) benzoquinones (BQ): 2-methyl-1,4-BQ, 2,6-dimethyl-1,4-BQ and 2,3, 5,6-tetramethyl-1,4-BQ; (3) naphthoquinones (NQ): 1,4-NQ, 2-methyl-1, 4-NQ and 2-hydroxy-1,4-NQ; (4) phenol derivatives: catechol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, t-butylhydroquinone, gallic acid and 4-aminophenol; (5) catecholamines: DL- and L-dopa, DL- and L-epinephrine, dopamine and L-norepinephrine; (6) thiols: L-cysteine methyl ester, L-cysteine ethyl ester, L-penicillamine and dithiothreitol; (7) diverse: 3,4-dihydroxyphenylacetic acid, hypoxanthine and xanthine, both in the presence of xanthine oxidase, L-ascorbic acid plus copper (II) and phenazine methosulfate. Among these oxidative mutagens, 25 were found to be uniquely positive in IC203. With the exception of BOOH and COOH, mutagenesis by all oxidative mutagens was inhibited by catalase present in rat liver S9, indicating that it is mediated by HP generation, probably in autoxidation reactions. These catalase-sensitive oxidative mutagens were poor inducers of mutations derived from 8-oxoguanine lesions, whereas such mutations were efficiently induced by organic hydroperoxides. The results support the usefulness of incorporating IC203 in the bacterial battery for testing of chemicals. The well-characterized oxidative mutagens available with the use of the WP2 Mutoxitest may serve as a reference in studies on the genotoxicity of oxidative stress.  相似文献   

12.
曹雪松  张自立 《动物学报》1992,38(2):214-219
本文对几种化学诱变剂诱发小鼠体内脾脏、骨髓和精原细胞的SCE进行了比较研究,同时分析了几类常见化合物在小鼠脾脏细胞中诱发SCE的活力。结果显示诱变剂在脾脏细胞中诱发SCE比骨髓和精原细胞敏感。几类化合物都能显著地诱发小鼠脾脏SCE的增加,与对照相比差异显著(P<0.05)或极显著(P<0.01),说明利用小鼠脾脏细胞检测环境诱变物是相当灵敏的。  相似文献   

13.
The induction of mutation by a variety of mutagens has been measured utilizing the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus in Chinese hamster ovary (CHO) cells (CHO/HGPRT) system). These mutagens include physical agents such as UV light and X-rays, and chemicals such as alkylating agents, ICR-191, and metallic compounds. This system can also be modified for study of the mutagenicity of promutagens such as dimethylnitrosamine (DMN) which require biotransformation for mutagenic action, either through the addition of a rat liver microsomal activation preparation or through a host-mediated activation step using Balb/c athymic mice.  相似文献   

14.
Mutascreen® is an automated instrument for bacterial mutagenicity testing. The biological principles of the Mutascreen assay are the same as those of the bacterial reverse-mutation assays, like the Ames test, but several operational principles are different. The Mutascreen assay takes place in wells containing only 400 μl of liquid medium. Also, the dispensing of the liquid medium, the bacterial tester strains, the metabolic activation system (S9), and the test solutions is all performed by a computer-controlled robot according to the user's preprogrammed instructions. The turbidity in up to 200 wells is monitored intermittently over a 24-h period by a vertical-pathway photometer, thereby avoiding measurement problems caused by sedimentation. The data for the resulting growth curves is stored for analysis. The auxotrophic growth pattern is altered characteristically by test solutions that are toxic or contain endogenous growth factor(s), while prototrophic growth is observed earlier in the 24-h period when revertants have been induced by the test solution. To compare the Mutascreen assay with the conventional plate assay, 36 chemicals including known carcinogens and noncarcinogens were tested. Both assays identified the same chemicals as mutagens and gave quantitatively similar results, thus testifying to the potential usefulness of automated bacterial mutagenicity testing.  相似文献   

15.
Two established chemical mutagens—ethylmethanesulphonate (EMS) and triethylenemelamine (TEM)—were tested for the ability to induce chromosome aberrations in mouse spermatogonia. While not a single aberration was detected following the EMS treatment, a low frequency of translocations and fragments was found in the TEM groups. These findings are in agreement with the data obtained with the specific locus mutation test as applied to male mouse premeiotic germ cells but contrast with the effectiveness of these chemicals in breaking chromosomes in male mouse postmeiotic germ cells. A differential sensitivity of post- and premeiotic germ cells to any kind of genetic damage by these chemical mutagens is most likely to be the correct interpretation of all the data. However, it is also suggested that a high proportion of translocations induced in spermatogonia by chemical mutagens may not be detectable by present methods.  相似文献   

16.
The L5178YTK+/? mouse lymphoma assay (MLA) has been utilized in several laboratories as a short-term test for chemical-induced forward mutation in cultured mammalian cells. In order to evaluate several technical modifications to the MLA, 42 chemicals representing 9 chemical classes were tested and the results were compared with those published elsewhere as well as with findings in a genetic toxicology test battery currently used in this laboratory. A positive response for the induction of TK+/? mutants was obtained for 26 chemicals. With the exception of p-aminophenol, all of these compounds were recognized mutagens or carcinogens and were represented of direct-acting and activation-dependent genotoxins. 16 compounds did not induce IK?/? mutanants and among these were 5 compounds that were considered to be mutagens or carcinogens. A comparison of the results of this study with those published elsewhere revealed a strong agreement among findings for this test irrespective of minor technical variations. It was concluded that th MLA is a useful system for identifying chemical mutagens in mammalian cells and can serve as a valuabel component in a genetic toxicology test battery.  相似文献   

17.
Mutagenicity studies have been used to identify specific agents as potential carconogens or other human health hazards; however, they have been used minimally for risk assessment or in determining permissible levels of human exposure. The poor predictive value of in vitro mutagenesis tests for carcinogenic activity and a lack of mechanistic understanding of the roles of mutagens in the induction of specific cancers have made these tests unattractive for the purpose of risk assessment. However, the limited resources available for carcinogen testing and large number of chemicals which need to be evaluated necessitate the incorporation of more efficient methods into the evaluation process. In vivo genetic toxicity testing can be recommended for this purpose because in vivo assays incorporate the metabolic activation pathways that are relevant to humans. We propose the use of a multiple end-point in vivo comprehensive testing protocol (CTP) using rodents. Studies using sub-acute exposure to low levels of test agents by routes consistent with human exposure can be a useful adjunct to methods currently used to provide data for risk assessment. Evaluations can include metabolic and pharmacokinetic endpoints, in addition to genetic toxicity studies, in order to provide a comprehensive examination of the mechanism of toxicity of the agent. A parallelogram approach can be used to estimate effects in non-accessible human tissues by using data from accessible human tissues and analogous tissues in animals. A categorical risk assessment procedure can be used which would consider, in order of priority, genetic damage in man, genetic damage in animals that is highly relevant to disease outcome (mutation, chromosome damage), and data from animals that is of less certain relevance to disease. Action levels of environmental exposure would be determined based on the lowest observed effect levels or the highest observed no effect levels, using sub-acute low level exposure studies in rodents. As an example, the known genotoxic effects of benzene exposure at low levels in man and animals are discussed. The lowest observed genotoxic effects were observed at about 1–10 parts per million for man and 0.04–0.1 parts per million in subacute animal studies. If genetic toxicity is to achieve a prominent role in evaluating carcinogens and characterizing germ-cell mutagens, minimal testing requirements must be established to ascertain the risk associated with environmental mutagen exposure. The use of the in vivo approach described here should provide the information needed to meet this goal. In addition, it should allow truly epigenetic or non-genotoxic carcinogens to be distinguished from the genotoxic carcinogens that are not detected by in vitro methods.  相似文献   

18.
We have utilized in vivo drug metabolism for detecting the mutagenicity of known indirectly-acting chemical mutagens. Exponentially growing Chinese hamster ovary (CHO) cells were incubated with plasma derived from treated rats containing active metabolites of the test chemicals. The genotoxicity was assessed by the 18 of tested chemical mutagens. Plasma from rats treated with known non-mutagens did not increase the frequencies of SCEs. The results indicate that this method could be useful for the demonstration of genotoxicity of chemicals which need metabolic activation to be effective, and especially those which are not effective, when in vitro activation conditions (S9 mixture) are used.  相似文献   

19.
Summary The induction of cytogenetic damage (micronuclei) in mouse fetal blood was studied with four selected mutagens: cyclophosphamide, procarbazine, trenimon, and mitomycin-C. For comparison the standard micronucleus test on maternal bone marrow was also performed. In contrast to the results obtained from maternal bone marrow the changes in the cellular composition in fetal blood were only slight after treatment with mutagens. A significant and dosepdependent increase in the incidence of micronucleated fetal blood cells was found with all four mutagens. The inducibility of micronuclei by indirect mutagens was particularly interesting. The three mutagens other than mitomycin-C induced a higher frequency of micronucleated polychromatic erythrocytes in fetal blood cells than in maternal bone marrow. The results indicate that this modified micronucleus test is well suited and useful for mutagenicity screening of environmental chemicals and especially for assessment of risks to the fetus when pregnant females are exposed to environmental chemicals.Supported by the Deutsche Forschungsgemeinschaft, Bonn-Bad Godesberg  相似文献   

20.
Animal welfare organisations have long been concerned about the use of animals for ecotoxicity testing. Ecotoxicity testing is a necessary part of the statutory risk assessment of chemicals that may be released into the environment. It is sometimes also carried out during the development of new chemicals and in the investigation of pollution in the field. This review considers the existing requirements for ecotoxicity testing, with particular reference to practices in the European Union, including the recent REACH system proposals, before discussing criticisms that have been made of existing practices for environmental risk assessment. These criticisms have been made on scientific and ethical grounds, as well as on questions of cost. A case is made for greater investment in the development of alternative testing methods, which could improve the science, as well as serving the cause of animal welfare. It has frequently been suggested that the statutory requirements for environmental risk assessment are too rigid and bureaucratic. A case is made for flexibility and the greater involvement of scientists in the risk assessment procedure, in the interests of both improved science and improved animal welfare.  相似文献   

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