农药污染对蚯蚓的群落结构与超微结构影响的研究

报道了农药污染对蚯蚓的群落结构与超微结构影响的研究,结果表明：随着农药污染程度增加,蚯蚓的种类和数量则减少。超微结构在扫描电镜下可观察到重污染区壮伟环毛蚓（Pheretimarobusta）胃粘膜出现溃疡灶,并产生穿孔现象;在中污染区只有微绒毛萎缩病变;在重污染区发现肠粘膜上的纤毛发生紊乱及萎缩,纤毛顶端膨大呈球形。对精子观察可见在中污染区就出现了畸形精子。在透射电镜下观察可见重污染区壮伟环毛蚓胃肠道粘膜上皮细胞中的粗面内质网（RER）出现扩张,高尔基复合体也产生扩张状,线粒体发生肿胀,线粒体嵴消失呈空泡状。另可见细胞核膜间隙扩张、断裂,核染色质边集或减少,胞质呈大片空白。蚯蚓以上病变指标均能很灵敏反映土壤农药污染程度。     

Health risk assessment of heavy metal exposure through vegetable consumption around a phosphorus chemical plant in the Kaiyang karst area,southwestern China

The phosphorus chemical industry is an important source of heavy metals in farmland. Vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the pollution status and health risks of heavy metals in vegetables around a phosphorus chemical plant in Kaiyang County, Guizhou Province, southwestern China, were assessed, and the low-accumulation vegetables were screened by bioaccumulation factor (BAF) and cluster analysis. Results showed the average concentrations of Hg, As, Cd, Pb, Cr, Mn, Co, and Zn in vegetables were 0.015, 0.728 0.382, 0.227, 0.850, 27.227, 0.525, and 6.438 mg/kg, respectively. The single-factor pollution index showed that Cd was moderately polluted, and Cr, Hg, As, and Pb were slightly polluted. The Nemerow pollution index showed that the overall heavy metal pollution was classified as moderately polluted. The accumulation of heavy metals in different vegetables varied greatly, and chard, crown daisy, chayote, pumpkin, eggplant, white radish, sweet potato, carrot, and potato were selected as the low-accumulator vegetables. The consumption of all vegetables except chayote poses both carcinogenic and noncarcinogenic risks; among them, the consumption of sweet potato leaves has the highest health risks. The local population needs to adjust plantation structure and change dietary habits, and government should strengthen the management of phosphorus chemical plant pollution.

     

重金属对蚯蚓的毒性毒理研究

通过室内模拟实验以及对株洲市重金属污染区农田土壤中采样，进行了重金属对蚯蚓的毒性毒理研究．毒性实验表明，各重金属元素４８ｈ的ＬＤ５０分别为：Ｃｄ１０００ｍｇ／ｋｇ，Ｐｂ８１２ｍｇ／ｋｇ，Ｃｕ６３３ｍｇ／ｋｇ，Ｈｇ３０４ｍｇ／ｋｇ，Ｚｎ５２８ｍｇ／ｋｇ，Ｃｒ４２８ｍｇ／ｋｇ．对蚯蚓毒理研究证明，重金属对蚯蚓酯酶同工酶有抑活作用，而重金属对蚯蚓过氧化物酶同工酶有激活作用．在光镜下观察，可见重金属污染可引起蚯蚓的体表溃疡及产生肿瘤，可使胃肠道粘膜层出血、背血管肿胀，同时可引起胃肠道粘膜上皮细胞产生萎缩或溃疡灶．蚯蚓特有的黄色细胞团污染程度不同而显示出消长规律．在电镜下可见到在重污染区的蚯蚓胃肠道粘膜上皮细胞中的ｒＥＲ肿胀、高尔基体膨大，线粒体嵴消失，甚至空泡化或解体．另可见细胞核膜间隙肿胀、断裂、核质外溢，胞质自溶．蚯蚓以上病变的大小是随土壤重金属污染区的污染级别而定；各病理变化指标均能定性地反映土壤重金属污染状况．     

狼蛛优势种群的12S rRNA对长期农药胁迫的分子响应

应用12SrRNA基因序列分析探讨了狼蛛优势种群对长期农药胁迫的分子响应机制.研究显示:(1)拟水狼蛛Piratasubpiraticus和拟环纹豹蛛Pardosapseudoannulata在长期农药胁迫下的12SrRNA基因第三结构域序列均发生了明显改变,即碱基组成由315bp和300bp分别减少为301bp和299bp,转换/颠换为17/5和11/10,核苷酸变异百分数达到0.095和0.083,同源性仅分别为85.8%和91.7%;(2)分子水平上表明拟水狼蛛较拟环纹豹蛛对农药的胁迫更为敏感;(3)供试两种狼蛛标本的基因组DNA的4个碱基对中以A和T的变异频率最高,属农药敏感型碱基对;(4)长期农药胁迫下供试两种狼蛛标本的12SrRNA基因片段的共同突变位点规律显示:192～228片段是其农药胁迫的敏感区.图2表3参9     

转Bar基因稻谷全蛋白对体外培养小鼠淋巴细胞的毒性

为了评价转基因大米Bar68-1全蛋白的急性细胞毒性,分别以25、50、100和200μg·mL-1转基因大米Bar68-1全蛋白孵育昆明小鼠淋巴细胞,并各孵育2 h、6 h、24 h,然后通过体外试验用CCK-8及中性红摄取试验检测细胞毒性大小。在经过不同的孵育时间段后,阳性对照组淋巴细胞的细胞存活率与空白对照组相比,存在显著差异(p0.05)。其中,CCK-8试验、中性红试验测得细胞存活率存在着明显的损伤作用-时间效应关系。转基因大米Bar68-1全蛋白组孵育的淋巴细胞存活率与非转基因大米D68全蛋白组孵育的淋巴细胞相比无明显差异(p0.05),且与空白对照组细胞存活率差异不显著(p0.05)。结果显示,转基因大米Bar68-1全蛋白与非转基因大米D68全蛋白急性细胞毒性效应相似,对小鼠淋巴细胞无明显急性毒性。     

土壤重金属污染对蚯蚓（Opisthopora）影响的研究

研究了重金属污染区蚯蚓的群落结构，污染指示种类，以及污染影响的毒理指标，结果表明：随着重金属程度的增加，蚯蚓种类减少，蚯蚓体内重金属元素富集量增加，蚯蚓毒理实验表明：Ｃｄ中毒后过氧化物同工酶活性增加，脂酶工同酶活性减弱，Ｐｂ中毒后蚯蚓过氧化物酶和胆酶同工酶活性均增加。