title: Multigenerational effects of tris(1,3-dichloro-2-propyl) phosphate on the free-living ciliate protozoa Tetrahymena thermophila exposed to environmentally relevant concentrations and after subsequent recovery.
abstract: Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is considered a re-emerging environmental pollutant, and exposure to environmentally relevant concentrations has been shown to cause individual developmental toxicity in zebrafish and the water flea (Daphnia magna). However, multigenerational effects during exposure to TDCIPP and after subsequent recovery were unknown. In the present study, individuals of a model aquatic organism, the ciliated protozoan, T. thermophila were exposed to environmentally-relevant concentrations of TDCIPP (0, 300 or 3000 ng/L) for 60 days (e.g., theoretically 372 generations) followed by a 60-day period of recovery, during which T. thermophila were not exposed to TDCIPP. During exposure and after exposure, effects at the molecular, histological, individual and population levels were examined. Multigenerational exposure to 300 or 3000 ng TDCIPP/L for 60 days significantly decreased numbers of individuals, sizes of individuals, expressed as length and width of bodies, number of cilia, and depth and diameter of basal bodies of cilia, and up-regulated expressions of genes related to assembly and maintenance of cilia. Complete or partial recoveries of theoretical sizes of populations as well as sizes of individuals and expressions of genes were observed during the 60-day recovery period. Effects on number of cilia and depth and diameter of basal body of cilia were not reversible and could still be observed long after cease of TDCIPP exposure. Collectedly, and shown for the first time, multigenerational effects to T. thermophila were caused by exposure to environmentally relevant concentrations of TDCIPP. Also, there were multi-generational effects at the population level that were not caused by carry-over exposure to TDCIPP. The "permanent" alterations and their potential significance are discussed.
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xufa
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Guanyong
authors.initials: G
authors.lastname: Su
authors.affiliation: Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada; School of Biological Sciences, University of Hong Kong, Hong Kong Special Administrative Region; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210089, China.
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Hunan, Changde 415000, China. Electronic address: liuchunshengidid@126.com.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Liu
mesh_terms: D000818:Animals; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008962:Models, Theoretical; D009943:Organophosphorus Compounds / Q000633:toxicity*; D016808:Tetrahymena thermophila / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009943:Organophosphorus Compounds; D014874:Water Pollutants, Chemical; C017779:tris(2,3-dichloropropyl)phosphate
keywords: Exposure; Gene expression; Organophosphate esters; Protozoa; Transmission electron microscopy