title: Inhibitory mechanism of phthalate esters on Karenia brevis.
abstract: The occurrence of phthalate esters (PAEs), a class of widely used and environmentally prevalent chemicals, raises concern to environmental and human health globally. The PAEs have been demonstrated to inhibit algae growth, but the underlying mechanisms remain unclear. In this research, diethyl ortho-phthalate (DEP), diallyl phthalate (DAP), di-n-butyl ortho-phthalate (DBP), di-iso-butyl ortho-phthalate, and benzyl-n-butyl ortho-phthalate (BBP) were screened from 11 species of PAEs to study their inhibitory effects on Karenia brevis and determine their target sites on algae. With increasing the alkyl chains of these five PAEs, the values of EC50,96h decreased. The content of malondialdehyde increased with the continuous accumulation of reactive oxygen species (ROS) in the algae cells. Moreover, the superoxide dismutase and catalase contents were first activated and then inhibited. The ultrastructures of Karenia brevis cells were detected by transmission electron microscopy, and cells treated with PAEs exhibiting distorted shapes and large vacuoles. Thus, the algae were damaged by ROS accumulation, resulting in lipid oxidation and algal growth inhibition. The inhibitors of the electron transport chain showed that the sites of ROS production and accumulation in K. brevis cells under DEP and BBP were the mitochondria and chloroplast, respectively. Moreover, the target sites of DAP and DBP were both the chloroplast and mitochondria. These results are useful for controlling PAEs contamination in and revealing the fate of PAEs in aquatic ecosystem.
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.affiliation: Weifang People's Hospital, Weifang, Shandong, 261041, China.
authors.forename: Fuling
authors.initials: F
authors.lastname: Wen
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China. Electronic address: lifengmin@ouc.edu.cn.
authors.forename: Fengmin
authors.initials: F
authors.lastname: Li
authors.affiliation: School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liang
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China. Electronic address: zhenghao2013@ouc.edu.cn.
authors.forename: Hao
authors.initials: H
authors.lastname: Zheng
mesh_terms: D002374:Catalase / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects*; D003993:Dibutyl Phthalate / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D004141:Dinoflagellida / Q000187:drug effects* / Q000254:growth & development; D004952:Esters / Q000494:pharmacology*; D006801:Humans; D008315:Malondialdehyde / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects*; D010795:Phthalic Acids / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D004952:Esters; D010795:Phthalic Acids; D017382:Reactive Oxygen Species; D003993:Dibutyl Phthalate; D008315:Malondialdehyde; C032279:phthalic acid; D002374:Catalase; D013482:Superoxide Dismutase; C049098:diallyl phthalate; C025605:diisobutyl phthalate; C007379:diethyl phthalate; C027561:butylbenzyl phthalate
keywords: Karenia brevis; Lipid peroxidation; Phthalate esters