重铬酸钾对蚕豆根尖细胞致畸效应的研究

以蚕豆根尖为材料,研究重铬酸钾对蚕豆根尖细胞的致畸效应。采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的重铬酸钾为诱变剂,测定蚕豆根尖细胞的微核率和染色体畸变率。结果表明:重铬酸钾能诱发较高频率的微核率,即在一定浓度范围内,其微核率随重铬酸钾处理浓度的升高而增加,但高于一定浓度后反而呈下降趋势;不同浓度的重铬酸钾均使蚕豆根尖细胞有丝分裂指数增大;重铬酸钾还能诱导蚕豆根尖细胞产生较高频率的染色体畸变,且产生多种类型的染色体畸变。结论是重铬酸钾对蚕豆根尖细胞具有明显的致畸效应。     

乙酸铜对蚕豆根尖细胞致畸效应

采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的乙酸铜为诱变剂,选择不同的处理时间,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明：乙酸铜能诱发较高频率的微核率,处理6h、12h时微核率均随着乙酸铜浓度的升高而增加,具有明显的剂量效应;处理24h时在实验浓度范围内,其微核率随乙酸铜浓度的升高而增加,但高于一定浓度后反而呈下降趋势。不同浓度的乙酸铜在不同处理时间均使蚕豆根尖细胞有丝分裂指数增大。乙酸铜还能诱导蚕豆根尖细胞产生较高频率的染色体畸变,且产生多种类型的染色体畸变。因此,乙酸铜对蚕豆根尖细胞具有明显的致畸效应。     

提高辐射诱变育种效果及辐射遗传效应的研究：Ⅲ作物辐射遗传效应 …

试验结果证明：１．γ辐射处理可导致水稻和蚕豆芽中可溶性蛋白质与同工酶谱的变化;２．γ射线诱发蚕豆根尖细胞畸变率、断片率、微核率、染色体畸变率与辐照剂量的关系均符合模式Ｙ＝ａ＋ｂｘ＋ｃｘ＾２,呈抛物线变化趋势;３．微核率、断片率与核畸变率、染色体畸变率呈正相关。从而作者认为微核率、断片率可以作为检测染色体辐射效应的可靠指标;４．γ射线照射可引起蚕豆根尖细胞染色体带型的变化。     

提高辐射诱变育种效果及辐射遗传效应的研究Ⅲ作物辐射遗传效应的研究

试验结果证明：１．γ辐射处理可导致水稻和蚕豆芽中可溶性蛋白质与同工酶谱的变化;２．γ射线诱发蚕豆根尖细胞畸变率、断片率、微核率、染色体畸变率与辐照剂量的关系均符合模式Ｙ＝ａ＋ｂｘ＋ｃｘ￣２,呈抛物线变化趋势;３．微核率、断片率与核畸变率、染色体畸变率呈正相关。从而作者认为微核率、断片率可以作为检测染色体辐射效应的可靠指标;４．γ射线照射可引起蚕豆根尖细胞染色体带型的变化。     

CO2激光对蚕豆诱变效应试验研究

７０年代以来,全国已有２０多个省市,近百个单位开展激光在农业上应用的研究,并对２０多种作物２００多个品种进行激光育种的研究。试验表明：激光在刺激作物生长,早熟增产以及诱发变异、改良品种等都有一定的效果,并培育出一些新品种应用于生产。然而,激光对作物的作用机制,特别是遗传机理方面的研究报道尚少。本试验目的是探讨ＣＯ２激光对蚕豆根尖细胞染色体畸变的影响及田间农艺性状的变异情况,分析细胞染色体畸变与农艺性状变异的相关性及其遗传传递情况,为作物激光诱变育种提供依据。本试验采用功率密度为３９４ｍＷ／ｃｍ２的ＣＯ２激光照射蚕豆萌动种子,观察其对蚕豆根尖细胞染色体畸变及幼苗生长的影响,探讨ＣＯ２激光照射后蚕豆植株农艺性状的变异及其遗传传递情况。试验结果表明：ＣＯ２激光不同时间照射蚕豆萌动种子,均能使根尖细胞产生染色体畸变,且畸变类型相似;同时,对Ｌ１幼苗生长有明显的抑制作用,Ｌ２植株高度、分枝数及结荚数等农艺性状均产生不同程度的变异。其中分枝数这一性状的变异能传递给Ｌ３,其余性状的变异则属生理损伤所致。     

硫酸铜对蚕豆根尖细胞有丝分裂的影响

以蚕豆根尖为材料,研究硫酸铜对蚕豆根尖细胞的遗传毒性效应。采用蚕豆根尖细胞的微核试验方法和染色体畸变试验方法,以不同浓度的硫酸铜为诱变剂,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明:不同浓度的硫酸铜均能使蚕豆根尖细胞有丝分裂指数明显增加,即5个实验组的分裂指数均明显高于对照组(P<0.01或P<0.001);不同浓度的硫酸铜对蚕豆根尖细胞有丝分裂各期百分数的影响有异;能诱发较高频率的微核率,即在一定浓度范围内,其微核率随硫酸铜处理浓度的升高而增加,但随着硫酸铜浓度的进一步升高而呈下降趋势;硫酸铜还能诱导染色体产生多种类型的畸变,染色体畸变率随硫酸铜处理浓度的升高而增加,随着硫酸铜浓度的进一步升高而呈下降趋势,但均明显高于对照组(P<0.001)。结论是硫酸铜对蚕豆根尖细胞具有明显的遗传毒性效应。     

利用闪蚕豆根尖细胞诱变法监测铲河西安河段污染的研究

早在兰十年代,国外学者就发现在射线作 用下引起的染色体畸变E17、七十年代以来,广 泛利用染色体畸变来检验射线和化学药剂的致 突变性ue.is坛目前,在国外已利用染色体畸变 来监测环境污染,美国环保局已把有关项目作 为监测环境污染的指标。．0 在国内,利用动、 植物在环境诱变物作用下引起染色体畸变、姊 妹染色单体交换、间期微核增加这些效应来监 测环境污染进行过探索〔3'-91。以蚕豆为材料, Francesca Degrassi建立了诱变剂检测系统us] 国内也有以此为手段进行污染监测的报道 n0,11]。我们利用蚕豆根尖细胞染色体畸变和微 核方法对流经西安东郊工业区的铲河水污染进 行了对比研究,结果如下。     

平阳霉素三种成份诱发染色体畸变的研究

本文报道了抗癌新药平阳霉素(PYM)三种成份(A_2、A_5、A_6)诱发蚕豆根尖细胞染色体畸变的效应。结果表明PYM的主要成份A_5的诱变能力显著高于A_2和A_6,从而找出了平阳霉素诱变能力大于博莱霉素的原因。同时观察到平阳霉素可诱发出大量特异的散碎型染色体畸变。上述三种成份诱发的畸变绝大多数属于染色体畸变,很少有染色单体畸变。另外并出现大量的微核,证明PYM很可能是一种不依赖S期效应的诱变剂。     

重铬酸钾对蚕豆根尖细胞致畸效应的研究

以蚕豆根尖为材料,研究重铬酸钾对蚕豆根尖细胞的致畸效应。采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的重铬酸钾为诱变剂,测定蚕豆根尖细胞的微核率和染色体畸变率。结果表明：重铬酸钾能诱发较高频率的微核率,即在一定浓度范围内,其微核率随重铬酸钾处理浓度的升高而增加,但高于一定浓度后反而呈下降趋势;不同浓度的重铬酸钾均使蚕豆根尖细胞有丝分裂指数增大;重铬酸钾还能诱导蚕豆根尖细胞产生较高频率的染色体畸变,且产生多种类型的染色体畸变。结论是重铬酸钾对蚕豆根尖细胞具有明显的致畸效应。Abstract：We studied the aberrant effects of different concentrations of potassium dichromate on Vicia Faba root tip cells. The micronucleus and chromosome aberration assay was conducted to determine the micronucleus rate and chromosome aberration rate of Vicia faba root tip cells induced by potassium dichromate. The result indicated that potassium dichromate could increase the micronucleus rate of Vicia faba root tip cells. Within certain range of concentration the rate of micronucleus was found to be increased with the increase of potassium dichromate concentration,but beyond this range the rate of micronucleus decreased with further increase of potassium dichromate concentration. The potassium dichromate at different concentrations could increase the cell mitosis index. Besides,it also caused various types of chromosome aberration,and the rates of chromosome aberration were always higher than that of the control group. The conclusion of this study was that potassium dichromate has obvious teratogenic effect on vicia faba root tip cells.     

博莱霉素对提高亚硝基乙基脲诱变效应的影响

本实验利用亚硝基乙基脲(NEU)处理及附加博莱霉素(Bleomycin,简写为BL)后处理对蚕豆幼根诱发染色体畸变进行了研究。结果指出,后处理诱发染色体畸变数量显著的高于NEU单独的处理,它们占有的百分率分别为20.4％及35.4％。这种表现被认为是基于连接酶通过BL的抑制而失活。由NEU所诱发的染色体初级断裂不能为连接酶所修复。反之,当NEU处理的浓度较高时,附加BL后处理对提高畸变率的效果则不复存在。后一现象归之于连接酶受到诱变剂的损伤。 有关BL后处理在高等植物上的遗传学效果将另行实验研究。     

Number of chromosome aberrations induced by chemical carcinogens in the cells of patients with 2 forms of xeroderma pigmentosum

A study was made of the effects of a chemical mutagen of the "gamma-type"--methylmethansulfonate (MMS) and of mutagen of the "UV-type"--4-nitroquinolin-1-oxide (NQO) and 7-brommethylbenz(alpha)antracen (BMBA) exerted on chromosome aberration frequency in lymphocytes of patients with classical Xeroderma pigmentosum and with a so-called form II of the disease on different stages of the cell cycle. Mutagens were added to PHA stimulated lymphocyte cultures every 3 hours, simultaneously with pulse 3H-thymidine labelling, to fix the stage of the cell cycle at the moment of treatment. NQO and BMBA treatments were found to increase the frequency of chromosome aberrations in classical XP cells, whereas MMS was not found to. In the XP II cells, defective in repair of both UV and gamma damaged DNA, chromosome aberrations yield is higher than in normal cells after all the three mutagens treatment. The data obtained show the correlation between DNA repair and chromosome aberrations yield.     

Comparison of DNA-repair synthesis,chromosome aberrations and induction of micronuclei in cultured human fibroblast,Chinese hamster ovary and central mudminnow (Umbra limi) cells exposed to chemical mutagens

In mammalian cells it has previously been observed that low DNA-repair activity is correlated wtih high chromosome-aberration frequency. Since fish cells typically express comparatively low amounts of DNA repair, the chromosome aberration test holds potential as a sensitive fish genotoxicity assay. A comparison of in vitro DNA-repairm activity showed HF > CHO > Ul-H = Ul-F following exposure to MNNG and 4NQO. Although peak chromosome-aberration frequency varied CHO > Ul-H > HF, at comparable mutagen concentrations the relationship was Ul-H > HF > CHO following 4NQO exposure and Ul-H > HF = CHO after MNNG exposure. Analyzing for chromosome aberrations at high mutagen concentrations was not possible due t mitotic inhibition/toxicity which varied according to the mutagen and cell line. Micronuclei frequency varied CHO > Ul-H > HF = Ul-F. In CHO and Ul-H, a 10–15 fold increase over the controls compares with only a 2–3 fold increase for HF and Ul-F. These differences are likely related, in part, to the cell-division rate of each line and the coincident repair of the damaged DNA. Reasons for the lack of negative correlation between DNA repair and chromosomal damage in fish cells are discussed.     

蚕豆染色体鞘的免疫荧光显示和其抗原的分析

本文应用本实验室发现的着染HeLa细胞染色体鞘的一例红斑狼疮病人抗血清对分离出的蚕豆染色体及核和蚕豆根尖生长点压片进行了免疫荧光染色,从两种不同制片方法得到的染色体上均染出了清晰的染色体鞘免疫荧光。之后又用此血清对蚕豆三天龄幼苗中(去除子叶、种皮)提取出的总蛋白进行Western印迹分析,获得的带型显示分子量为41K,39K,18K,17K的蛋白质可与抗血清中的抗体特异性结合,另有分子量为87K,38K,35K,34K,32K的蛋白质也可能具有与抗体特异性结合的能力。     

蚕豆染色体鞘的免疫荧光显示和其抗原的分析

The autoimmune antiserum specific to pellicle of human metaphasic chromosomes from a lupus patient was used to stain metaphasic chromosome Vicia faba by means of indirect immunoflourescence method. It was found that the pellicles of vicia metaphasic chromosomes was positively stained. The antigen of Vicia faba recognized by the antiserum was also examined by PAGE of total cell lysate and western blotting.     

新制癌菌素和平阳霉素诱发蚕豆染色体畸变的比较研究

本文报道了新制癌菌素(NCS)能诱发植物染色体畸变,同时观察了利用咖啡因后处理对NCS、PYM诱发染色体畸变的影响,研究了PYM切断DNA断头的性质。结果表明,NCS切割DNA产生3'-羟基末端和3'-磷酸末端;咖啡因能封闭3'-羟基末端抑制DNA的修复,从而提高诱变频率。PYM加咖啡因后处理,其染色体畸变频率与PYM单独处理无明显差异。说明PYM切断DNA所得到的产物,不是3'-羟基末端,而是3'-磷酸末端。     

DNA damage processing and aberration formation in plants

Various types of DNA damage, induced by endo- and exogenous genotoxic impacts, may become processed into structural chromosome changes such as sister chromatid exchanges (SCEs) and chromosomal aberrations. Chromosomal aberrations occur preferentially within heterochromatic regions composed mainly of repetitive sequences. Most of the preclastogenic damage is correctly repaired by different repair mechanisms. For instance, after N-methyl-N-nitrosourea treatment one SCE is formed per >40,000 and one chromatid-type aberration per approximately 25 million primarily induced O6-methylguanine residues in Vicia faba. Double-strand breaks (DSBs) apparently represent the critical lesions for the generation of chromosome structural changes by erroneous reciprocal recombination repair. Usually two DSBs have to interact in cis or trans to form a chromosomal aberration. Indirect evidence is at hand for plants indicating that chromatid-type aberrations mediated by S phase-dependent mutagens are generated by post-replication (mis)repair of DSBs resulting from (rare) interference of repair and replication processes at the sites of lesions, mainly within repetitive sequences of heterochromatic regions. The proportion of DSBs yielding structural changes via misrepair has still to be established when DSBs, induced at predetermined positions, can be quantified and related to the number of SCEs and chromosomal aberrations that appear at these loci after DSB induction. Recording the degree of association of homologous chromosome territories (by chromosome painting) and of punctual homologous pairing frequency along these territories during and after mutagen treatment of wild-type versus hyperrecombination mutants of Arabidopsis thaliana, it will be elucidated as to what extent the interphase arrangement of chromosome territories becomes modified by critical lesions and contributes to homologous reciprocal recombination. This paper reviews the state of the art with respect to DNA damage processing in the course of aberration formation and the interphase arrangement of homologous chromosome territories as a structural prerequisite for homologous rearrangements in plants.     

Cytogenetic effects of 50 Hz magnetic fields of different magnetic flux densities

Cytogenetic investigations were performed in human peripheral blood lymphocytes following exposure to 50 Hz magnetic fields alone or in combination with the chemical mutagen mitomycin C or with X-rays. It was found that magnetic fields up to 2500 microT did not significantly influence the chromosome aberration and sister chromatid exchange frequency. Also, the combined treatments failed to indicate the presence of any synergistic, potentiating, or antagonistic effect between the ELF magnetic fields and the mutagens. However, there were two exceptions: Cells exposed to 504 microT magnetic fields before and during cultivation displayed a statistically significant decrease in sister chromatid exchange frequency. Also, when cells were cultivated in the presence of 88.4 microT magnetic fields following X-ray exposures there was a significant increase in chromosome aberration frequency compared to X-ray exposure alone.