镉胁迫下蚯蚓(Eisenia fetida)生物标志物的应激响应研究

为研究重金属镉胁迫下蚯蚓生物标志物的响应并综合评价污染风险,设置不同浓度镉污染的人工土壤微宇宙体系,进行为期30d蚯蚓胁迫实验.比较不同镉浓度下蚯蚓生长繁殖(日增重倍数和日增殖倍数)和生化指标,包括过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和谷胱甘肽硫转移酶(GST)的活性,糖原(Gn)、可溶性蛋白(SP)、丙二醛(MDA)和金属硫蛋白(MT)的含量,结果表明:日增重倍数和日增殖倍数随着镉浓度升高显著降低,镉对蚯蚓生长繁殖具有抑制作用;镉对大多数生化指标有显著影响,其中SP、CAT、MT、GST含量或活性随着镉浓度的升高而显著提升,但MDA、Gn、SOD表现出不规则变化趋势.生物标志物响应指数(BRI)和综合生物标志物响应指数(IBR)表明,环境胁迫效应随着镉浓度增加而加强.BRI显示在0.1,1和10 mg·kg-1镉浓度下,蚯蚓分别面临着轻度胁迫、较大胁迫和严重胁迫.多项生物标志物对镉有复杂的响应,相较于IBR,BRI具有操作简单、适用范围广的突出优点.

Study on response of biomarkers in earthworm (Eisenia fetida) exposed to cadmium

In order to study the response of earthworm biomarkers under cadmium exposure and comprehensively evaluate the pollution risk, an artificial soil microcosms contaminated with different concentrations of cadmium was set up to conduct a toxicity experiment of earthworms (Eisenia fetida) for 30 days. The growth and reproduction of earthworms (daily weight increment rate and daily proliferation rate), along with biomarkers , including the catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glycogen (Gn), soluble protein (SP), malondialdehyde (MDA) and metallothionein (MT),were compared under different cadmium concentrations. The results showed that daily weight increment rate and daily proliferation rate decreased significantly with increased cadmium exposure, indicates cadmium inhibited the growth and reproduction of earthworm. Cadmium had significant effects on most biomarkers, in which SP, CAT, MT and GST were significantly increased with the elevated cadmium concentration. However, MDA, Gn and SOD indicated irregular trends. Biomarker response index (BRI) and integrated biomarker response index (IBR) showed that the environmental stress effect enhanced with elevated cadmium concentration. BRI revealed that earthworms are faced with mild stress, greater stress and severe stress respectively at 0.1 mg(kg^-1, 1 mg(kg^-1, and 10 mg(kg^-1 cadmium concentrations. Most biomarkers have complex responses to cadmium and BRI has the advantages of simple operation and broad sphere of application compared to IBR.