镉铜单一及复合胁迫对双齿围沙蚕(Perineresis aibuhitensis)消化酶活性和抗氧化指标的影响

采用实验生态学方法,研究了Cd~(2+)-Cu~(2+)单一及复合胁迫3d、6d、9d对双齿围沙蚕(Perinereis aibuhitensis)消化酶活性和抗氧化指标的影响。结果表明,沙蚕的各项不同指标对Cd~(2+)、Cu~(2+)胁迫的响应表现出不同的变化趋势,复合胁迫中Cd~(2+)-Cu~(2+)对沙蚕各指标的影响存在交互效应。沙蚕3种消化酶活性大小为淀粉酶蛋白酶脂肪酶。Cd~(2+)、Cu~(2+)单一胁迫能激发沙蚕淀粉酶活性,激发作用强于复合胁迫。Cd~(2+)、Cu~(2+)单一胁迫实验前期低浓度组蛋白酶被抑制,高浓度组被诱导,复合胁迫实验前期Cd~(2+)-Cu~(2+)对蛋白酶活性的影响存在协同作用。Cd~(2+)、Cu~(2+)胁迫对沙蚕脂肪酶活性整体表现出抑制作用。Cd~(2+)、Cu~(2+)胁迫诱导沙蚕超氧化物歧化酶(SOD),整体上激活过氧化氢酶(CAT)活性。Cd~(2+)单一胁迫实验组过氧化物酶(POD)均被显著诱导,具有"剂量-效应"关系,Cu~(2+)单一胁迫实验后期POD被显著诱导,复合胁迫实验中,低浓度Cu~(2+)组POD被显著诱导,高浓度Cu~(2+)组POD被显著抑制。实验组沙蚕谷胱甘肽过氧化物酶(GXH-Px)活性和丙二醛(MDA)含量均高于对照组,复合胁迫实验前期,GXH-Px活性与Cu~(2+)浓度呈正相关关系,与Cd~(2+)浓度呈负相关关系。显著的效应-剂量间相关关系存在于特定时间(3d、6d)的MDA含量,沙蚕MDA含量用作监测海洋重金属污染的生物标志物的可能性较大。

EFFECTS OF SINGLE Cu, Cd, AND Cu-Cd COMBINED STRESS ON DIGESTIVE ENZYME ACTIVITIES AND ANTIOXIDANT INDEXES OF PERINEREIS AIBUHITENSIS

An experimental ecology method was conducted to investigate digestive enzyme activities and antioxidant indexes of Perinereis aibuhitensis exposed to different concentrations of heavy metal ions Cd²⁺, Cu²⁺, and their combination (Cd²⁺-Cu²⁺) from 3d to 9d. Results show that the factors of Perinereis aibuhitensis show different variation patterns under different concentrations of metal ions, and all factors were affected by the interaction effect of Cd²⁺ and Cu²⁺ in the combined stress experiments. The activity of amylase in P. aibuhitensis was the highest among the three digestive enzymes, and the activity of protease was higher than that of lipase. Single Cd²⁺ and Cu²⁺ could stimulate amylase to cope with the stress environment, and stimulation of single Cd²⁺ and Cu²⁺ stress on amylase was stronger than that of Cu-Cd combined stress. Compared with the control group, when P, aibuhitensis were exposed to low concentrations of single Cd²⁺ and Cu²⁺, their protease activities decreased in the early experimental period; when exposed to high concentrations of single Cd²⁺ and Cu²⁺, their protease activities increased in the early experimental period. There was a synergy interaction of Cd²⁺ and Cu²⁺ on protease activities in the early period of combined stress experiment. Treatment with Cd²⁺ and Cu²⁺ had an inhibitory effect on lipase activities. Cd²⁺ and Cu²⁺ stress showed inductive effect on the activities of the SOD and CAT. POD activities in the single Cd²⁺ stress groups were significantly induced and positively correlated with the Cd²⁺ stress intensity. In the later period of the experiment, the POD activities in the single Cu²⁺ stress groups significantly increased. In the combined stress experimental process, the POD activities in the low concentration of Cu²⁺ groups were significantly induced, and those in the high concentration of Cu²⁺ groups were significantly inhibited. GXH-Px activities and MDA contents in all experimental groups were significantly higher than those of the control group. In the combined stress experimental process, GXH-Px activities had obviously positive correlation with Cu²⁺ level, and showed a negative correlation with Cd²⁺. When P. aibuhitensis were exposed to Cd²⁺ and Cu²⁺ stress for 3d or 6d, some significant effect-dosage relationships occurred, the content of MDA could be one of potential biomarkers to monitor marine contamination of heavy metals.