Yu Tsai Hsin, Dafre Alcir Luiz, de Aragão Umbuzeiro Gisela, Franciscon Elisangela
Technology School, Campinas State University, Limeira, SP, 13484-332, Brazil.
Ecotoxicology. 2015 Jan;24(1):232-7. doi: 10.1007/s10646-014-1348-x. Epub 2014 Sep 14.
Disperse Red 1 (DR1) is an azo dye that can reach the aquatic environment through the discharge of textile industrial wastewaters. It has been tested in Daphnia similis and shown to be highly toxic. Cytochrome P450 (CYP) is a class of enzymes involved in phase I of detoxification, while glutathione S-transferase (GST) are a class of phase II enzymes. No information about phase I or II dye metabolism in microcrustacea were found in the literature. In this study we identified CYP and GST enzymes involved in the metabolism of DR1 in juveniles of D. similis. Using spectrophotometric analysis we showed that 50 % of the dye was absorbed by the organisms, which could be confirmed by the reddish color of animals exposed to DR1, however adsorption cannot be ruled out. GST activity increased from 280 to 615 nmol(-1 )min(-1 )mg when D. similis were exposed for 48 h to 0.2 mg L(-1) DR1 and from 274 to 815 nmol(-1) min(-1 )mg when exposed to 5 mg L(-1). Data clearly demonstrate that exposure to DR1 can stimulate a strong induction of GST activity, whose participation in DR1 metabolism needs to be confirmed. The induction of GST activity seems to be dependent on CYP activity, since treatment with SKF535A, a CYP inhibitor, blocked the DR1-dependent GST induction. We speculate that GST is involved in DR1 metabolism in Daphnia and that CYP activity is necessary to induce GST-activity, which is an indirect evidence of its role in the biotransformation of DR1.
分散红1（DR1）是一种偶氮染料，可通过纺织工业废水排放进入水生环境。它已在相似水蚤中进行测试，显示出高毒性。细胞色素P450（CYP）是参与解毒第一阶段的一类酶，而谷胱甘肽S-转移酶（GST）是一类第二阶段酶。在文献中未发现关于微型甲壳动物中染料第一阶段或第二阶段代谢的信息。在本研究中，我们鉴定了参与相似水蚤幼体中DR1代谢的CYP和GST酶。通过分光光度分析，我们表明50%的染料被生物体吸收，这可通过暴露于DR1的动物的红色来证实，然而不能排除吸附作用。当相似水蚤暴露于0.2 mg L⁻¹ DR1 48小时时，GST活性从280增加到615 nmol⁻¹ min⁻¹ mg，当暴露于5 mg L⁻¹时，从274增加到815 nmol⁻¹ min⁻¹ mg。数据清楚地表明，暴露于DR1可刺激GST活性的强烈诱导，其在DR1代谢中的参与需要得到证实。GST活性的诱导似乎依赖于CYP活性，因为用CYP抑制剂SKF535A处理可阻断DR1依赖的GST诱导。我们推测GST参与相似水蚤中DR1的代谢，并且CYP活性是诱导GST活性所必需的，这是其在DR1生物转化中作用的间接证据。
