甲醛对洋葱根尖细胞的遗传毒性效应

将不同浓度(0.1%、1.0%、1.5%和3%)的甲醛溶液作为诱变剂,分别处理洋葱根尖24、36和48 h.通过常规染色体压片技术,观察洋葱根尖细胞有丝分裂现象.研究甲醛对洋葱根尖细胞有丝分裂指数(MI)和染色体畸变的影响,探讨甲醛的遗传毒性和洋葱作为甲醛污染指示植物的可行性.结果表明:不同浓度的甲醛溶液均能使洋葱根尖...     

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。     

Assessment of micronuclei and chromosomal anomalies of five biocompatible materials in mice

In vivo genetic toxicology tests measure direct DNA damage or the formation of gene or chromosomal mutations, and are used to predict mutagenic and carcinogenic potential of compounds for regulatory purposes. These adverse genotoxic effects may be manifested in the form of gene mutations, structural chromosomal aberrations (CA), recombination, and numerical changes. The present investigation was carried to assess genotoxic effects of five different implantable biomaterials developed in different laborataries of Sree Chitra Tirunal Institute of Medical Sciences and Technology. All biomaterials were developed for clinical applications. CA and micronuclei (MN) studies are biomarkers of genotoxicity testing. Leachants from the extract of biomaterials are capable of inducing structural and numerical chromosomal changes. The studies were conducted in Swiss albino mice with the physiological saline extract of materials together with cyclophosphamide and physiological saline as positive and negative controls. Animals were administered intraperitoneally (ip) with a single injection of test, positive (cyclophosphamide), and negative (physiological saline) control and sacrificed after 24 or 48?h. Bone marrow cells were collected for CA and MN assays. Data showed that all five biomaterials did not significantly exert genotoxic effects. Hence, the study indicates that these biomaterials do not induce any chromosomal anomalies.     

Analysis of the genotoxic potential of low concentrations of Malathion on the Allium cepa cells and rat hepatoma tissue culture

Based on the concentration of Malathion used in the field, we evaluated the genotoxic potential of low concentrations of this insecticide on meristematic and F₁ cells of Allium cepa and on rat hepatoma tissue culture (HTC cells). In the A. cepa, chromosomal aberrations (CAs), micronuclei (MN), and mitotic index (MI) were evaluated by exposing the cells at 1.5, 0.75, 0.37, and 0.18 mg/mL of Malathion for 24 and 48 hr of exposure and 48 hr of recovery time. The results showed that all concentrations were genotoxic to A. cepa cells. However, the analysis of the MI has showed non-relevant effects. Chromosomal bridges were the CA more frequently induced, indicating the clastogenic action of Malathion. After the recovery period, the higher concentrations continued to induce genotoxic effects, unlike the observed for the lowest concentrations tested. In HTC cells, the genotoxicity of Malathion was evaluated by the MN test and the comet assay by exposing the cells at 0.09, 0.009, and 0.0009 mg/5 mL culture medium, for 24 hr of exposure. In the comet assay, all the concentrations induced genotoxicity in the HTC cells. In the MN test, no significant induction of MN was observed. The genotoxicity induced by the low concentrations of Malathion presented in this work highlights the importance of studying the effects of low concentrations of this pesticide and demonstrates the efficiency of these two test systems for the detection of genetic damage promoted by Malathion.     

一种水质污染生物监测的新方法——蝌蚪肠细胞染色体畸变分析

发展了一种水生脊椎动物蝌蚪肠细胞染色体畸变的分析方法,可作为诱变剂污染水源的早期报警系统。该方法的优点:1)灵敏度高;2)蝌蚪在我国分布广、数量多、捕捉方便、费用低、易饲养管理。尤其是蝌蚪的核型由22条大的中部和亚中部着丝点染色体所组成,适于毒理遗传学研究;3)蝌蚪具有转化前诱变剂或前致癌剂为活性成份的微粒体活化系统。     

镉对洋葱根生长和细胞分裂的影响

研究了不同浓度氯化镉溶液对洋葱根的生长,细胞分裂和染色体形态的影响.结果表明,随Cd~(2+)浓度增加,根的生长速率递减;随处理时间延长,每单位时间的根生长速度递减或停止,根尖细胞有丝分裂指数随Cd~(2+)的浓度增高和处理时间延长而递减.不同浓度Cd~(2+)都能引起染色体畸变,恢复培养后均能恢复生长,染色体畸变率降低     

飞机某模拟涂装试样加速腐蚀与自然暴露的对比研究

目的研究飞机某结构模拟试样加速腐蚀试验与自然暴露试验的相关性。方法选取飞机某结构模拟试样分别进行实验室加速腐蚀试验和海南西沙外场自然暴露试验,以宏/微观形貌、失光率、色差等级、腐蚀产物成分等作为评价指标,对试样表面涂层的腐蚀损伤情况进行长期观测和对比研究,对加速腐蚀2个周期和户外暴露2年的疲劳试样疲劳寿命和疲劳断口形貌进行对比分析。结果加速腐蚀试验2个周期和自然暴露试验2年试样的试验过程色差变化规律一致,色差变化等级均为2级,光泽度变化规律一致,加速腐蚀试验后为3级,户外自然暴露户外为4级、棚下为3级,在螺钉边缘均出现面漆剥落现象。7B04铝合金试样疲劳寿命断口的韧窝和孔洞的数量都没有发生明显的变化,在显著度为0.05时,两组疲劳寿命的t检验量为1.6971,疲劳寿命无显著差异。结论加速腐蚀试样表面涂层的腐蚀程度介于户外和棚下暴露试样之间,这一结果与加速环境谱的编制原则相一致,也进一步表明加速试验环境谱正确性。疲劳寿命无显著差异,表明加速腐蚀试验可以较好地模拟飞机实际工作环境对试样疲劳性能造成的影响。     

邻苯二甲酸二丁酯对蚕豆胚根细胞微核形成的影响及毒理机制

研究常用增塑剂邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)对农作物生长的影响,为农用地膜及其残留物的环境安全性评估提供实验依据。以蚕豆为试材,DBP处理浓度为0(CK)、9 mmol·L-1、18 mmol·L-1、27 mmol·L-1和36 mmol·L-1,培养24 h、48 h和72 h后,观测根尖细胞染色体结构变化,测试胚根抗氧化酶活性。结果显示:DBP暴露的蚕豆胚根生长速率减缓;随着DBP暴露时间延长,根尖正在进行分裂的细胞被阻断在有丝分裂前期的比例增加,微核率升高,出现多种类型的染色体畸变;DBP暴露的胚根超氧化物歧化酶(superoxide dismutase,SOD)活性提高5.41%~29.68%,过氧化物酶(peroxidase,POD)活性随DBP浓度增加而递减,过氧化氢酶(catalase,CAT)活性显著降低14.00%~43.08%。结果表明,DBP对蚕豆胚根具有遗传毒性,且能够破坏纺锤丝的结构。     

In vitro assessment of genotoxic and oxidative effects of zinc borate

Zinc borate is used as flame retardant for plastics and cellulose fibers, paper, rubber, and textiles. Despite its wide industrial use, there is limited information concerning its toxicity. The aim of the present study was to investigate the concentration dependence (0–280 mg L^?1) of its genotoxic activity on cultured human lymphocytes by using sister chromatid exchange and chromosomal aberration assays. Total antioxidant capacity and the extent of oxidative stress were also determined. Zinc borate was found to be non-genotoxic at all tested concentrations. It exhibited antioxidant activity at concentrations lower than 40 mg L^?1, and total oxidative stress levels were not changed at any applied concentration of zinc borate.