聚六亚甲基双胍对蛋白核小球藻的毒性效应研究

Toxic effects of polyhexamethylene biguanide(PHMB)on Chlorella pyrenoidosa

聚六亚甲基双胍(polyhexamethylene biguanide,PHMB)是一种高分子聚合物杀菌消毒剂,在医药、日用化工和水产养殖等行业广泛应用。为探究PHMB对水生植物的毒性效应,设置0、1、2、4 mg·L^(-1)浓度的PHMB对蛋白核小球藻(Chlorella pyrenoidosa)进行0、3、6和9 d的胁迫试验。结果表明:PHMB对蛋白核小球藻的生长具有抑制作用,且随胁迫浓度的升高而增强。PHMB显著降低蛋白核小球藻叶绿素a和b含量,引起藻细胞的细胞壁开裂和内含物外渗,损伤细胞器结构。PHMB显著降低蛋白核小球藻中抗氧化酶超氧化物歧化酶和谷胱甘肽过氧化物酶活性,并引起丙二醛含量升高。对蛋白核小球藻光合作用相关基因pbsA、rbcL和rbcS的表达检测发现,这些基因在低浓度的PHMB处理后表达升高,而在高浓度的PHMB处理后表达下降,说明小球藻对PHMB胁迫产生反馈调节。综上,PHMB可抑制蛋白核小球藻的光合作用及生长,为PHMB的生态风险评估提供了理论依据。

As a macromolecule polymer disinfectant,polyhexamethylene biguanide(PHMB)is widely used in medicine,chemical,aquaculture and other industries.To study the phytotoxic effects of PHMB,Chlorella pyrenoidosa was exposed to PHMB at 0,1,2 and 4 mg·L^(-1) for 0,3,6 and 9 d,respectivily.The results indicated that PHMB inhibited the growth of C.pyrenoidosa and represent in a time-dose effect.Meanwhile PHMB significantly reduced the content of chlorophyll a and b in C.pyrenoidosa,leading to cell wall cracked,extravasation and damaged the structure of organelles.PHMB significantly reduced the SOD and GSH-Px activities,and increased the MDA content of C.pyrenoidosa.Moreover,the expression of C.pyrenoidosa photosynthesis-related genes pbsA,rbcL and rbcS significantly upregulated at low concentrations of PHMB,and downregulated at high concentrations of PHMB,which reflected a feedback regulation of PHMB stress response.The study revealed the inhibition of PHMB on the photosynthesis and the growth of C.pyrenoidosa and provided theoretical basises for PHMB phytotoxic risk assessment.