Chen Jianzhong, Song Lirong, Dai Jian, Gan Nanqin, Liu Zhili
Department of Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China.
Toxicon. 2004 Mar 15;43(4):393-400. doi: 10.1016/j.toxicon.2004.01.011.
Microcystins are naturally occurring hepatotoxic cyclic heptapeptides produced by some toxic freshwater cyanobacterial species. In this study, crude extract of toxic cyanobacterial blooms from Dianchi Lake in southwestern China was used to determine the effects of microcystins on rape (Brassica napus L.) and rice (Oryza sativa L.). Experiments were carried out on a range of doses of the extract (equivalent to 0, 0.024, 0.12, 0.6 and 3 microg MC-LR/ml). Investigations showed that exposure to microcystins inhibited the growth and development of both rice and rape seedlings, however, microcystins had more powerful inhibition effect on rape than rice in germination percentage of seeds and seedling height. Microcystins significantly inhibited the elongation of primary roots of rape and rice seedlings. Determination of the activities of peroxidase and superoxide dismutase demonstrated that microcystin stress was manifested as an oxidative stress. Using ELISA, microcystins were examined from the extract of exposed rape and rice seedlings, indicating that consumption of edible plants exposed to microcystins via irrigation route may have health risks. Significantly different levels of recovered microcystins between exposed rice and rape seedlings suggested that there might be different tolerant mechanisms toward microcystins.
微囊藻毒素是由一些有毒淡水蓝藻物种产生的天然存在的肝毒性环状七肽。在本研究中，使用中国西南部滇池有毒蓝藻水华的粗提物来确定微囊藻毒素对油菜（Brassica napus L.）和水稻（Oryza sativa L.）的影响。对一系列剂量的提取物（相当于0、0.024、0.12、0.6和3微克MC-LR/毫升）进行了实验。研究表明，暴露于微囊藻毒素会抑制水稻和油菜幼苗的生长发育，然而，微囊藻毒素对油菜种子发芽率和幼苗高度的抑制作用比对水稻更强。微囊藻毒素显著抑制油菜和水稻幼苗初生根的伸长。过氧化物酶和超氧化物歧化酶活性的测定表明，微囊藻毒素胁迫表现为氧化胁迫。使用酶联免疫吸附测定法（ELISA）对暴露后的油菜和水稻幼苗提取物中的微囊藻毒素进行了检测，这表明通过灌溉途径接触微囊藻毒素的可食用植物的消费可能存在健康风险。暴露后的水稻和油菜幼苗中回收的微囊藻毒素水平存在显著差异，这表明可能存在对微囊藻毒素的不同耐受机制。
