title: Biomethylation and Volatilization of Arsenic by Model Protozoan Tetrahymena pyriformis under Different Phosphate Regimes.
abstract: Tetrahymena pyriformis, a freshwater protozoan, is common in aquatic systems. Arsenic detoxification through biotransformation byT. pyriformisis important but poorly understood. Arsenic metabolic pathways (including cellular accumulation, effluxion, biomethylation, and volatilization) ofT. pyriformiswere investigated at various phosphate concentrations. The total intracellular As concentration increased markedly as the external phosphate concentration decreased. The highest concentration was 168.8 mg·kg-1dry weight, after exposure to As(V) for 20 h. Inorganic As was dominant at low phosphate concentrations (3, 6, and 15 mg·L-1), but the concentration was much lower at 30 mg·L-1phosphate, and As(V) contributed only ~7% of total cellular As. Methylated As contributed 84% of total As at 30 mg·L-1phosphate, and dimethylarsenate (DMAs(V)) was dominant, contributing up to 48% of total As. Cellular As effluxion was detected, including inorganic As(III), methylarsenate (MAs(V)) and DMAs(V). Volatile As was determined at various phosphate concentrations in the medium. All methylated As concentrations (intracellular, extracellular, and volatilized) had significant linear positive relationships with the initial phosphate concentration. To the best of our knowledge, this is the first study of As biotransformation by protozoa at different phosphate concentrations.
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China. xxyincas@gmail.com.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. xxyincas@gmail.com.
authors.forename: Xixiang
authors.initials: X
authors.lastname: Yin
authors.affiliation: Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan 250014, China. wlhkxy@gmail.com.
authors.forename: Lihong
authors.initials: L
authors.lastname: Wang
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China. zhanchaozhang123@gmail.com.
authors.forename: Zhanchao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China. glfan410@gmail.com.
authors.forename: Guolan
authors.initials: G
authors.lastname: Fan
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China. jjlou418@gmail.com.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China. kzsun@mail.sdu.edu.cn.
authors.forename: Kaizhen
authors.initials: K
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. gxsun@rcees.ac.cn.
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Sun
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D001711:Biotransformation; D005618:Fresh Water / Q000382:microbiology; D008658:Inactivation, Metabolic; D010710:Phosphates / Q000378:metabolism*; D013769:Tetrahymena pyriformis / Q000378:metabolism*; D014835:Volatilization
chemical_list: D010710:Phosphates; D001151:Arsenic
keywords: Tetrahymena pyriformis; accumulation; arsenic; biotransformation; phosphate; protozoan