涕灭威及其复合物对茎线虫DNA的影响

选择了一种毒性很高的氨基甲酸酯农药涕灭威、一种最常见的阴离子表面活性剂十二烷基苯磺酸钠(SDBS)及一种土壤中普遍存在的天然物质腐殖酸,组成两种复合污染体系;研究了它们对茎线虫的生态毒理效应和对DNA的影响.结果发现,涕灭威-SDBS复合体系在4 d内对茎线虫的DNA造成了明显的损伤,而涕灭威-SDBS-腐殖酸复合体系在8 d内对茎线虫DNA造成的损伤却远远低于未加入腐殖酸的复合体系.关于涕灭威及其复合污染物对茎线虫的生态毒理效应和对DNA损伤的研究尚未见文献报道.     

MDMA(3,4亚甲基二氧甲基苯丙胺)对小鼠睾丸细胞微核率及染色体畸变率的影响

通过连续20 d对雄性小鼠灌胃染毒3,4-亚甲基二氧基甲基苯丙胺(3,4-methylenedioxymethamphetamine,MDMA)后,探究MDMA对雄性小鼠睾丸组织细胞微核率及染色体畸变率的影响.将雄性小鼠随机分为MDMA低(5.0mg/kg)、中(10.0mg/kg)、高(20.0 mg/kg)三个染毒剂量组,采用生理盐水做阴性对照,每日染毒1次.于末次给药后第二天,取小鼠睾丸组织细胞,采用常规微核(micronucleus,MN)试验,检测小鼠睾丸细胞微核率的改变;同时采用染色体畸变试验(chromosomal aberration test)探究MDMA对小鼠睾丸细胞染色体畸变率的影响.微核试验结果表明MDMA中、低剂量组小鼠睾丸细胞微核率与阴性对照组比较差异无显著性(P0.05),而高剂量与低剂量组小鼠睾丸细胞微核率及阴性对照组比较,差异均有显著性(P0.01).染色体畸变试验结果中,MDM高、中剂量组染色体畸变率分别与阴性对照组比较差异有显著性(P0.05),剂量组之间染色体畸变率差异也有显著性(P0.05).结论通过微核试验与染色体畸变试验结果同时得出:在该实验剂量内MDMA高剂量组能诱导小鼠睾丸组织细胞微核率增加,高剂量组及中剂量组可以使小鼠睾丸细胞染色体畸变率增高,说明其对雄性小鼠睾丸遗传物质有一定的损伤效应.图4,表2,参10.     

Er3+和稀土多元复合肥对蚕豆根尖细胞的微核效应

稀土元素是镧系金属元素的总称,在地壳中含量稀少,约占１５×１０－６．我国对稀土元素的开发利用较早,特别是农业上稀土多元复合肥常与农药一起使用,这对生物和环境的影响为人们所关注,给环境研究带来了新课题．目前对稀土元素的研究主要集中在地球化学、农业化学和...     

Comparison of basal cytotoxicity of seven carbamates in CHO-K1 cells

The cytotoxic effects of seven carbamate pesticides, aldicarb, aldicarb sulfone, aldicarb sulfoxide, benfuracarb, pirimicarb, propoxur and thiobencarb, were compared in Chinese hamster ovary (CHO-K1) cell line of Circetulus griseus. The endpoints evaluated were lysosomal function by neutral red assay and mitochondrial integrity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT assay). The carbamates tested were evaluated in both serum-free medium and in serum-containing medium. Results demonstrate that CHO-K1 lysosomes appeared more susceptible to propoxur, aldicarb and its metabolites than mitochondria. Aldicarb was the most toxic carbamate pesticide tested on CHO-K1 cells and aldicarb sulfoxide the least. The presence of foetal calf serum (FCS) diminished significantly the cytotoxicity of tested carbamates.     

涕灭威在土壤中的降解特性

用实验室模拟培养方法研究了土壤中涕灭威及其代谢物在不同条件下的降解规律，探讨了影响降解的主要因素。结果表明，温度和土壤微生物活性是影响降解的重要因素，温度升高、有机质含量增加均大大加快涕灭威残留物降解。２５℃时，涕灭威在不同类型表层土壤中Ｔ＿（０．５）为３～８ｄ，其残留物总量的Ｔ＿（０．５）为３０～６５ｄ．在温度低、徽生物活性小的深层土壤中涕灭威Ｔ＿（０．５）为３４～１２０ｄ，残留物总量的Ｔ＿（０．５）为１５９～６８６ｄ，其中亚矾较难降解。     

农药氰戊菊酯和三氟氯氰菊酯对蚕豆根尖细胞的遗传损伤

采用蚕豆根尖微核技术研究了农药氰戊菊酯、三氟氯氰菊酯对蚕豆根尖细胞的遗传损伤.测定了不同浓度氰戊菊酯、三氟氯氰菊酯(5×10-10～5×10-2g·L-1)诱导下的蚕豆根尖细胞微核率、有丝分裂指数和染色体畸变率.结果表明,氰戊菊酯、三氟氯氰菊酯均能诱发较高的微核率,在一定浓度范围内,微核率随两种农药处理浓度的升高而增加,但随着处理浓度的进一步升高微核率反而呈下降趋势;两种农药均可使蚕豆根尖细胞有丝分裂指数增大;并能诱导蚕豆根尖细胞产生较高频率、多种类型的染色体畸变.氰戊菊酯和三氟氯氰菊酯对蚕豆根尖细胞具有明显的遗传毒性.     

利用不同植物进行DNA损伤彗星实验的方法比较

为了研究彗星实验在植物DNA损伤检测中的应用,以多种植物材料为对象,进行了植物彗星实验的比较研究.分别分离了蚕豆、菠菜、洋葱、菜豆、大蒜、水稻等植物组织的细胞核,并以彗星实验方法研究了H2O2引起的植物细胞核DNA损伤.电泳后发现H2O2处理组植物细胞核出现明显拖尾,而对照组没有出现拖尾或拖尾较小.研究结果表明彗星实验是一种可以在单细胞水平上研究植物DNA损伤程度的手段,具有灵敏、简单、快速的优点.采用合适的细胞核分离方法,能够将彗星实验应用于多种植物,研究其DNA损伤.蚕豆、菠菜、洋葱、菜豆、大蒜等植物的根尖和叶片都可以应用于植物彗星实验,但在本实验条件下利用水稻组织进行彗星试实验并没有获得明显的彗星图像,能否进行彗星实验可能受植物本身性质或实验条件等多种因素的影响.     

三叶鬼针草对蚕豆根尖遗传毒性的研究

化感作用是外来植物成功入侵和快速扩散的机制之一,为了探讨入侵植物三叶鬼针草(Bidens pilosa L.)的化感作用机制,运用蚕豆根尖微核技术和植物切片技术,研究了不同质量浓度的三叶鬼针草水浸提液对蚕豆(Vicia faba L.)根尖细胞的遗传损伤和对根生长的影响。结果表明,三叶鬼针草水浸提液对蚕豆根尖细胞有丝分裂及生长产生不同程度的抑制和损伤,具有明显的遗传毒性。水浸提液对蚕豆根尖的影响存在显著的时间效应和质量浓度效应。经切片测量统计,水浸提液促进了成熟区细胞平周分裂,使根尖细胞层数增加;同时显著地抑制了细胞伸长,使根尖缩短,整体表现为使根尖加粗变短。三叶鬼针草水浸提液抑制了细胞有丝分裂的正常进行,并随着水浸提液质量分数的升高,分裂期细胞数目下降,微核率逐渐升高。本研究结果表明三叶鬼针草水溶性化感物质对植物的遗传稳定性及细胞形态结构具有一定的影响,三叶鬼针草的化感作用可能是其成功入侵的机制之一。     

加拿大蓬挥发油经不同载体对蚕豆根尖的细胞毒性

采用悬空气法和土培法,研究了加拿大蓬（Erigeron canadensis L.）挥发油对蚕豆（Vacia faba L.）根尖细胞经不同载体的细胞毒性。结果表明：加拿大蓬挥发油对蚕豆根尖细胞的有丝分裂没有显著的影响,但显著抑制了幼根的生长,使根尖细胞产生了多种类型的染色体畸变,导致微核率升高。综合分析表明,加拿大蓬挥发油经土壤载体的化感作用大于经空气载体的化感作用,推测可能是土壤对挥发油的滞留作用增大了化感效应。     

The investigation of cytotoxic effects of refinery wastewater on root tip cells of Vicia faba L

The present study was carried out to evaluate the cytotoxic effects of refinery wastewater collected from different stations of the Kizilirmak river on Vicia faba L. root tip cells. For this aim, we used the germination percentage, root length, weight gain and micronucleus (MN) frequency as indicators of cytotoxicity. Additionally to the cytological analysis, DNA analyses were performed in root tips meristems of Vicia faba seeds treated with refinery wastewater. Heavy metal concentrations in the water samples were determined using atomic absorption spectrophotometer (AAS). The concentrations of heavy metals in the water were in the order of Pb>Zn>Fe>Cu>Ni>Cd>Hg. The highest germination percantage was observed in the control group (in proportion as 96%). Heavy metals in the water samples collected from Station I, II and III caused a decrease in the germination percentage as 48, 18 and 30%, respectively. The highest root length and weight gain was observed in the control group at the end of the experimental period. The least root length and weight gain was observed in seeds treated with wastewater collected from Station I. In the control group, the weights of all the seeds increased about 4.08 g when compared with initial weight. The root lengths of the control seeds were determined as 6.38 cm at the end of the experimental period. The weights of the seeds exposed to wastewaters obtained from Station I, II and III increased about 1.08, 3.03 and 2.01 g according to initial weight, respectively. Microscopic examination of V. faba root tip meristem cells showed that any example of the MN formation was not seen in the control group. The highest frequency of MN was observed in group treated with wastewater collected from Station I and least frequency of MN was observed in group treated with wastewater collected from Station II. It was also observed that the yields of DNA in the seeds exposed to wastewater were lower than recorded in the controls. Hence, DNA yields exposed to wastewater were run ahead on agarose gel according to the control group. The results clearly indicate that refinery wastewater had important cytotoxic effects on V. faba root tip cells. It was also observed that V. faba seeds are very sensitive and useful biomarkers for monitoring these effects in waters contaminated with heavy metals.     

澳门城市垃圾焚烧底灰的重金属淋溶及其遗传毒性评价

应用美国国家环境保护局推荐的毒性特性溶出程序(toxicitycharacteristicleachingprocedure,TCLP),以及ICP-MS和ICP-AES技术研究了澳门城市垃圾焚烧底灰中重金属的淋溶,并结合蚕豆根尖微核试验评价了其潜在的生态与健康风险.结果显示,该底灰淋溶出来的重金属元素:铝(Al)、锰(Mn)、钴(Co)和汞(Hg)的浓度低于0.01mg·L-1,铁(Fe)、铜(Cu)和钼(Mo)的浓度低于0.1mg·L-1,而铬(Cr)、锌(Zn)、硒(Se)、锶(Sr)、钡(Ba)和铯(Cs)的浓度在0.11mg·L-1￣2.19mg·L-1之间.需要注意的是淋溶液中铅(Pb)的浓度异常高,最高可达19.06mg·L-1,超过了美国相关标准的上限(5mg·L-1);对比不同条件下底灰中重金属的淋溶情况,表明溶解作用和淋溶液的pH值是影响其淋溶的2个重要因素.蚕豆根尖微核试验显示各淋溶液处理组根尖细胞微核率明显升高,与阴性对照组相比具有显著性差异(p<0.05),表明各淋溶液具有遗传毒性;随着淋溶液中重金属浓度的增加,蚕豆根尖细胞所表现出来的毒性效应增强,表明重金属是淋溶液具有遗传毒性的重要原因.     

蚕豆根尖微核技术的方法学新论

虽然蚕豆根尖微核技术已是一个成熟规范的检测污染物遗传毒性的方法,但其中仍涉及一些重要的方法学问题值得深入探讨和研究。本文在图示正确观测蚕豆根尖细胞内微核和染色体畸变,如染色体断裂、丢失及染色体桥等的基础上,提出应该对蚕豆根尖分裂相细胞及其染色体畸变进行观测,以便更加准确、细致地反映污染物作用的剂量-效应关系和分子机制。同时还就该方法的其他重要问题提出了自己的观点,供同行们深入探讨和研究,使之不断完善,更好地服务于环境监测和风险评价等领域。