Cd^(2+)对Cypridopsis vidua(介形纲)肠壁结构的毒性效应（英文）

Toxic effects of Cd^(2+) on the intestinal structure of Cypridopsis vidua(Ostracoda)

Cypridiopsis vidua是少数能在重污染水体中生存的介形类之一.本文采用急性毒性实验方法,研究了Cd^(2+)对介形类C.vidua及其肠壁结构的影响,结果表明,24、48、72和96h时Cd^(2+)对C.vidua的半致死浓度(LC_(50))分别为5.00、2.01、0.46和0.14mg/L,安全浓度为0.014 mg/L.在急性毒性试验的基础上,于安全浓度上下分别设置了两个Cd^(2+)实验浓度对介形类进行攻毒研究,目的是进一步探讨在安全浓度附近,Cd^(2+)对C.vidua肠壁细胞的损伤情况,实验持续7 d.显微结果显示,在安全浓度以下时,C.vidua的胃肠道结构基本没有受到损伤,但超过安全浓度后,C.vidua的胃肠道结构损伤程度于96 h以内表现出了一定的时间和剂量效应,但至第7天时部分幸存下来的C.vidua其受损胃肠道结构出现一定程度的恢复,但已无法恢复到最初的状态了;亚显微切片显示,肠壁细胞的膜结构、胞质、胞器等均有不同程度的损伤,且随镉离子浓度的升高损伤明显加剧,其中细胞的膜结构损伤尤为严重.

Cypridopsis vidua is one of the few ostracods which can surrive from heavy pollution water. The toxic effects of Cd2＋ on C. vidua and its intestinal ultrastructure were examined using a static renewal system. The LC50 values for cadmium in C. vidua were 5.00, 2.01, 0.46 and 0.14 mg/L at 24, 48, 72 and 96 h exposure respectively, and the safe concentration of Cd2＋ for long-term C. vidua survival was less than 0.014 mg/L. To observe the structure changes of its intestinal, four Cd2＋ concentrations were set up, and two of them were below the safe concentration of Cd2＋ （0.001 and 0.004 mg/L） and the other concentrations were above its safe concentration （0.016 and 0.064 mg/L）. The experiment lasted for 7 days. When microstructure of C. vidua was observed, the gastrointestinal orga- nization was not damaged below the safe concentration; while the degree of injury showed a certain amount of time and dose effects in 24-72 hours above the safe concentration, and some structures among those surviving animals were slightly recovered in 7 days under same concentration. Sub-microscopic analysis of intestinal cells of C. vidua in two concentrations （0.004 and 0.064 mg/L） groups showed, different degrees of structure damage were found in the cell membrane, cytoplasm and organelles, which worsened with increasing Cd2＋ con- centrations. Among these cellular structures, the damage to the membrane system of the cell was especially serious.