五氯苯酚对淡水双壳类背角无齿蚌ρ型谷胱甘肽S-转移酶表达的影响

Effects of PCP on the ρ-GST Expression in the Freshwater Bivalve Anodonta woodiana

谷胱甘肽S-转移酶(GST)在机体抗击氧化应激中发挥重要作用。前期研究表明,五氯苯酚(PCP)处理对背角无齿蚌(Anodonta woodiana)具有显著的氧化应激和急性毒性效应。为了探讨PCP慢性毒性效应,本研究将背角无齿蚌随机分为对照组和PCP处理组,PCP处理组和对照组分别用13.9 mg·L^-1和相同体积二甲亚砜处理;同时,克隆出ρ型谷胱甘肽S-转移酶并命名为ρ-GST,分析PCP对ρ-GST表达的影响。ρ-GST全长cDNA包含一个57 bp的5’端非编码区,291 bp的3’端非编码区和678 bp的开放阅读框。ρ-GST在背角无齿蚌斧足、外套膜、闭壳肌、心脏、肝胰腺、血淋巴和鳃中广泛表达。与对照组相比,PCP处理后肝胰腺ρ-GST mRNA在第1天、第3天和第15天分别增加18.18%、82.88%(P<0.05)和2.43倍(P<0.01);PCP处理后鳃中ρ-GST mRNA水平增加1.44倍以上(P<0.05);PCP处理后血淋巴中ρ-GST mRNA水平显著上调。背角无齿蚌ρ-GST表达水平上调有助于对抗PCP处理所产生的应激效应,提高动物环境耐受能力。

Glutathione S-transferases(GST)play a prominent role in protecting cells against oxidative stress.Our previous study showed that the reactive oxygen species(ROS)generated from pentachlorophenol(PCP)could cause an acute impact on freshwater bivalve Anodonta woodiana,but its chronic toxicity remain unclear.In order to investigate the chronic effect of PCP,clams A.woodiana were randomly grouped into PCP treated group in which animals were administrated with 13.9 mg·L^-1 PCP,and control group with similar volume of dimethyl sulfoxide.In addition,one GST sequences was isolated from A.woodiana and namedρ-GST.The full-length cDNA ofρ-GST contained a 5’unique taxpayer reference(UTR)of 57 bp,a 3’UTR of 291 bp and an open reading frame(ORF)of 678 bp encoding a polypeptide of 226 amino acids.The constitutive expression levels ofρ-GST was determined in different tissues including foot,mantle,adductor muscle,heart,hepatopancreas,hemocytes and gill.Administration of PCP could result in a significant increase ofρ-GST expression in the hepatopancreas,gill and hemocytes.In the hepatopancreas,ρ-GST increased by 18.18%,82.88%(P<0.05)and 2.43 times(P<0.01)at day 1,3 and 15 in contrasted with that of control group,respectively.In the gill,mRNA level ofρ-GST increased more than 1.44 times(P<0.05)compared with that of control group.In addition,expressions ofρ-GST was significantly induced after PCP treatment in the hemocytes.These results indicated that up-regulations ofρ-GST expression in bivalve A.woodiana reacted against oxidative stress derived from PCP treatment.