氯丁二烯的致突变性鉴定——大肠杆菌回变试验及枯草杆菌重组试验

近年来,国内外对氯丁二烯(chlorobutadi-ene,CBD)的致突变性有广泛的研究,且多数获阳性结果[1].本文选用大肠杆菌回变试验及枯草杆菌重组修复试验测试CBD的致突变性,同时     

金属化合物的重组缺陷型试验和诱变性研究

金属化合物的遗传毒性研究比较少。大约30年前,Demerec和他的同事报道某些铁、锰和汞的化合物在细菌中可引起点突变。Nishi-oka指出,重组缺陷型试验阳性金属化合物中,重铬酸钾、钼酸铵和亚砷酸钠是诱变剂。细菌重组缺陷型试验也证实砷、铬和硒化合物具有诱变性。作者对127种金属化合物,用重组缺陷型试验和回变试验进行诱变性检测。重组缺陷型试验用枯草杆菌H17(Rec~+arg~-try~-)和M45(Rec~-,arg~-try~-)菌株。在加金属化合物后和37℃培养之前进行“冷培养”,即培养皿在4℃保存24小时,这样延长了金属化合物和非正在     

金属化合物致突变性的探讨

王玉芝等(沈阳市劳动卫生职业病研究所)采用枯草杆菌芽胞重组试验法,对铬、镉钴等20种金属化合物作致突变检测。结果可见:铬、镉砷、钴等已确定为致癌的金属化合物呈阳性反应;而铅和铜呈阴性反应后;尚未见致癌作用报道的铊等金属化合物呈明显的阳性反应。在本实验中,呈阳性反     

饮水消毒剂一无机一氯氨的致突变性研究

本文用枯草杆菌重组修复试验(芽孢法)和大肠杆菌回变试验方法,研究了饮水消毒剂一氯氨(NH_2Cl)的致突变性。结果显示:NH_2Cl在检测DNA损伤及修复的枯草杆菌重组修复试验中,在加和不加S_9的条件下,当浓度分别为:3.24、6.47、12.94mM和3.64、7.28、14.56mM时,均未检出致突变性;在检测基因突变的大肠杆菌回变试验中,在加和不加S_9的条件下,当浓度分别是:2.82×10~(-3)、1.41×10~(-2)、7.04×10~(-2)mM和2.74×10~(-3)、1.37×10~(-2)、6.84×10~(-2)mM时,均获得了阳性结果。根据国际预访环境致突变物致癌物委员会意见,有理由认为,在本实验条件下,NH_2Cl为一致突变剂。     

四种金属化合物的联合致突变性探索

四种金属化合物的联合致突变性探索夏安莉，刘江风重庆市职业病防治院６３００６０铜、铬、镍和锌等化合物在工业生产中应用广泛，有些行业的工人（如电镀作业）要同时接触这几种金属化合物。重铬酸钾是已明确的致癌物和致突变物，同时接触重铬酸钾与其它金属化合物，其致...     

五氧化二钒的致突变性研究

五氧化二钒(V_2O_5)是工业上最常见的钒化合物,其用途愈来愈广.现用鼠伤寒沙门氏菌和大肠杆菌回变试验、小鼠显性致死试验和微核试验、枯草杆菌重组试验和人外周血淋巴细胞姊妹染色单体互换,来鉴定V_2O_5的致突性.     

内镜细胞刷几种低温灭菌方法的实验研究

目的：探讨几种低温灭菌方法对内镜细胞刷的灭菌效果。方法：内镜细胞刷浸染枯草杆菌黑色变种芽孢（ATCC9372），干燥后分别经戊二醛浸泡3h、4h、5h，戊二醛熏蒸3h、5h和环氧乙烷灭菌处理．采样培养7d。结果：内镜细胞刷经戊二醛浸泡3h、4h不能完全杀灭细胞刷污染的枯草杆菌黑色变种芽孢，浸泡5h，则可完全杀灭芽孢，达到灭菌合格；经戊二醛熏蒸3h、5h，不能完全杀灭细胞刷污染的枯草杆菌黑色变种芽孢；经环氧乙烷灭菌，能完全杀灭细胞刷污染的枯草杆菌黑色变种芽孢，达到灭菌合格。结论：戊二醛浸泡5h灭菌和环氧乙烷气体灭菌可有效杀灭内镜细胞刷污染的细菌芽孢，达到灭菌效果。     

某些金属及其化合物致突变性的研究近况

由于现代工业的迅猛发展,环境污染日趋严重,某些金属及其化合物的遗传毒性愈来愈受到人们的重视。有关这方面的研究报告和综述也日益增多。本文拟就某些金属及其化合物致突变性的短期试验结果及其解释作一综述。 一、某些金属致突变的短期试验结果 (一)砷 有些研究认为,砷的化合物既不能降解提纯的小牛胸腺DNA,也不能降低DNA合成的精确性。亚     

上海碳素厂空气污染对工人健康影响研究

本斫究采用人体健康监测和动物现场染毒等手段，调查了上海碳素厂空气污染对工人健康影响。斫究的结果得到以下一些印象：(1）碳素厂空气飘尘其有很强的致突变性，能引起奠基移码型突变．既含有直接致突物，又有间接致突变物，并以前者为主。各样品中以沥青仓库点致突变作用最强；(2)碳素厂生产性接触沥青烟尘能引起工人姐妹染色单体交换率增高；(3)碳素厂生产性接触沥青烟气对人体细胞免疫功能有抑制作用；(4)碳素厂冷压车间空气对大鼠肺细胞膜有一定损伤作用和肺组织免疫有一定抑制作用。     

巢式PCR快速检测炭疽芽孢杆菌

目的：快速简便地检测炭疽芽孢杆菌。方法：细菌培养物经反复冻融，SDS，蛋白酶K和煮沸处理后，作为PCR模板，根据炭疽芽孢杆菌质粒pX01中水肿因子（EF）基因设计两对引物，采用巢式PCR（nestedPCR)扩增目的基因，结果：从炭疽芽孢杆菌模板中成功扩增出1247bp的特异片段，而未在炭疽芽孢杆菌无毒株，蜡样芽孢杆菌和枯草杆菌模板中扩增出相应条带；第一次扩增能检出的最低细菌量是10^3拷贝；经再次巢式PCR，扩增出208bp的特异片段，最低检出的细菌数为10个拷贝，敏感性提高了100倍。结论：巢式PCR是一种快速，特异，敏感的检测炭疽芽孢杆菌的方法。     

枯草杆菌重组修复试验和Ames试验的比较研究

本文就枯草杆菌重组修复试验和Ames试验做了一些比较研究。结果显示两种方法对典型诱变剂的阳性检出率相当,对金属类诱变剂则以前法敏感;重组修复试验中又以芽胞法较标准划线法敏感。这种敏感性差异可能与实验原理有关。     

Isolation and Characterization of Heavy Metal Resistant Bacteria from Barak River Contaminated with Pulp Paper Mill Effluent,South Assam

A group of 15 heavy metal resistant bacteria were isolated from Barak River contaminated with paper and pulp effluents. These isolates displayed different degrees of chromium tolerance. Four isolates showed 34 %-49 % of growth at a concentration of 4.0 mM of Cr(6+) and subjected to chromium reduction assay under aerobic condition. The isolate E (4) showed highest reduction (34.38 %) followed by E (3) and K(6)PA6, both showed 28.75 % reduction and then D (2) (27.5 %) after 72 h of incubation. These 4 isolates also showed different degrees of resistance to other heavy metals like Ni, Cu, Co and Cd. Antibiotic sensitivity profile of these selected bacterial strains was determined against 10 different antibiotics. Isolate E (4) appeared to be most susceptible being inhibited by eight antibiotics and resistant to penicillin G and ampicillin. The isolate E (3) was resistant to as many as five antibiotics and showed susceptible responses to the rest of the antibiotics. Both the isolates K(6)PA6 and D (2) were resistant to four antibiotics and showed intermediate to susceptible responses to the rest of the antibiotics.     

对几种原代细胞彗星实验敏感性的探讨

目的 筛选一种动物原代敏感细胞用于彗星实验,以便更广泛地监测环境样品的遗传毒性。方法 用重铬酸钾(K2Cr2O7)和过氧化氢(H2O2)作为受试物,对小鼠的肝、脾、肾细胞进行彗星实验,观察K2Cr2O7和H2O2对这3种细胞造成的DNA损伤,从而判断细胞的敏感性。结果 以K2Cr2O7染毒,肝细胞的检测阈值(10nmol／L)低于脾和肾(1000nmol／L)。以H2O2染毒,在相同浓度下肝细胞迁移长度最大。结论 肝细胞在彗星实验中的敏感性最高、自身活化能力强,且取材方便、耗时短、费用低,可以作为一种敏感细胞应用于彗星实验,对环境样品进行遗传毒性监测。     

彗星试验银染法的优化及验证

在彗星试验中寻找一种最佳染色效果的银染法 ,拟取代溴化乙啶 (EB)染色。对选出的银染法从固定、染色、显色、脱色、染色温度等各个方面进行多次试验 ,达到最佳染色效果后 ,将优化的银染法用于检测两类化合物 -重铬酸钾 (K2 Cr2 O7)和 1,2—二氯乙烷 (1,2—dichloroethane,DCE)对两种类型细胞—小鼠脾细胞、人外周血淋巴细胞的DNA损伤作用 ,并与EB染色比较灵敏度。结果显示优化后的银染法是在彗星试验中成功建立的非荧光染色法 ,该法染色清晰、持久、背景颜色浅、染色对比度好、染色效果满意 ,方法操作简便、价廉 ;该法可检测出化合物对细胞的DNA损伤作用 ,与EB染色有相同阳性检出阈 ,可染出EB染色无法染上的DNA小片段。所以在彗星试验中该银染法可以取代EB染色     

三价铬和六价铬小鼠急性毒性及致突变性研究

目的比较不同价态铬化合物急性毒性及致突变毒性。方法采用鼠伤寒沙门菌／微粒体试验（Ames）实验、小鼠急性毒性实验和小鼠骨髓微核实验检测铬化合物的急性毒性和致突变毒性。结果K2Cr2O2的LD50明显高于CrCl3;Ames试验CrCl3呈阴性结果,K2Cr2O7呈阳性结果。小鼠骨髓微核实验CrCl3呈阴性结果;K2Cr2O7各剂量组微核率明显高于对照组（P〈0．05）。CrCl3和K2Cr2O1各剂量组骨髓细胞PCE／RBC比值随剂量的增高均呈现下降趋势,但均高于0．1。结论本实验表明CrCl3不具有致突变作用,K2Cr2O3不但急性毒性明显高于CrCl3,而且具有致突变作用。     

Oxidative stress induced by chromium (VI) in bone of suckling rats

Exposure to hexavalent chromium Cr(VI) compounds is of concern in many Cr-related industries and their surrounding environments. K(2)Cr(2)O(7) is widely recognized as an animal and human carcinogen, mutagen, and teratogen. The present study investigated the bone maturity of suckling rats whose mothers were treated with K(2)Cr(2)O(7). Experiments were carried out on female Wistar rats given 700 ppm of K(2)Cr(2)O(7) in their drinking water from the 14th day of pregnancy until day 14 after delivery. Exposing dams to K(2)Cr(2)O(7) caused disorders in the bone of their progeny. As corollary to this, malondialdehyde levels increased, while glutathione, a non-protein thiol and vitamin C decreased. Alteration of the antioxidant system in the treated group was also confirmed by the significant decline of superoxide dismutase, catalase, and glutathione peroxidase activities. Furthermore, K(2)Cr(2)O(7) induced changes in bone mineralization, especially calcium and phosphorus levels, which decreased. Whereas, in plasma and urine, they increased and decreased inversely. These results suggest that K(2)Cr(2)O(7) accelerated bone resorption activity. In fact, in treated pups, total tartrate-resistant acid phosphatase, which reflected bone resorption, was enhanced while total alkaline phosphatase, which reflected bone formation, was reduced. The impairment of bone function was corresponded histologically.     

Sensitivity of Allium and Nicotiana in cellular and acellular comet assays to assess differential genotoxicity of direct and indirect acting mutagens

We have evaluated the extent of DNA damage induced by direct and indirect mutagens by cellular and acellular comet assays in two plant systems, Nicotiana tabacum (wild type tobacco) and Allium cepa (common onion). The objectives of this study were: (1) to generate dose-response curves for DNA migration values from root and shoot nuclei of A. cepa and N. tabacum treated with the direct acting mutagens, ethyl methanesulphonate (EMS), hydrogen peroxide (H₂O₂) and the indirect acting mutagen, cadmium chloride (CdCl₂), (2) to assess the differential response between isolated nuclei and nuclei of root and shoot and of both plants and (3) to examine the differences of sensitivity between direct and indirect acting mutagens by cellular and acellular comet assays. Similar sensitivities were evident in both plant systems to direct and indirect acting mutagens. The combination of cellular and acellular comet assays provided valuable insight to the mode of action of the genotoxicants used. The data obtained demonstrated the estimable capacity of the two plant systems to evaluate genotoxicity under different stress conditions and suggests Allium is a more desirable test system for rapid monitoring of genotoxicity.     

Does potassium dichromate induce apoptosis in lymphocytes?

The aim of this work was to investigate the possibility of apoptosis in the human peripheral blood lymphocytes after treatment with potassium dichromate (K2Cr2O7), a potential occupational carcinogenic and mutagenic agent. Lymphocytes were stimulated by phytohemagglutinin, cultured for 72 h and incubated with either 0.2 mM or 0.4 mM K2Cr2O7 for the last 24 h or 48 h of culture. The condensation and margination of chromatin with emerging 'half-moon' structure, characteristic of apoptosis were observed. Phosphatidylserine displaced from the inner to outer side of the cellular membrane in 54% of cells after a 48-h incubation with 0.4 mM K2Cr2O7 (annexin-V+/PI-); 39% of these cells were of late apoptotic--secondary necrotic form (annexin-V+/PI+). Following the agarose gel electrophoresis of DNA, a 'ladder pattern' typical of apoptosis, was found. The results of the present study demonstrate that K2Cr2O7 can induce in the human peripheral blood lymphocytes changes similar to apoptotic ones.     

重铬酸钾对卵黄囊细胞膜脂质流动性的影响

为探讨重铬酸钾导致卵黄囊功能絮乱的机理,以１．６－二苯－１,３,５－已三烯（ＤＰＨ）为荧光探针,用荧光偏振技术观察重铬酸钾对大鼠卵黄囊细胞膜脂质流动性的影响。结果表明：重铬酸钾深度为１．０ｍｇ／Ｌ以上时,卵黄囊细胞膜脂质流动度（ＬＦＵ）降低（Ｐ〈０．０５）,胚胎发育受到抑制（Ｐ〈０．０５）,且都呈明显的剂量－效应关系。提示卵黄囊细胞膜脂质流动度改变可能是重铬酸钾对大鼠胚胎发育毒性的机理之一。     

用彗星试验区别凋亡细胞与普通DNA链断裂损伤细胞

应用彗星试验对地塞米松诱导的小鼠胸腺凋亡细胞与重铬酸钾诱导的普通DNA链断裂损伤细胞进行了比较研究。结果发现 :在彗星形态上 ,凋亡细胞具有明显的特征 ;在相同电泳条件下 ,凋亡细胞的彗星出现时间早 ;在剂量 反应关系上 ,凋亡细胞表现为凋亡指数增加 ,而DNA链断裂损伤细胞为彗星尾长增加 ;在修复的时效关系上 ,凋亡继续发展 ,普通DNA链断裂损伤有明显修复。研究表明 ,彗星试验不仅能敏感地检测DNA链断裂 ,而且可以了解DNA链断裂损伤的性质 ,对于研究肿瘤的发生、发展和转归具有重要意义。