As a typical organophosphorus flame retardant, tris (2-chloroethyl) phosphate (TCEP) has been widely detected in various environmental media. Toxicity of TCEP to vertebrates have been investigated, but potential effects on lower trophic level species were unknown to date. In this study, toxic effects and molecular mechanisms of toxic actions of TCEP on the aquatic protozoan Tetrahymena thermophila were evaluated by use of phenotypic observations, transcriptome sequencing analysis and real-time quantitative PCR detection. Exposure to 0.044, 0.411 or 4.26 mg/L TCEP for 5 days decreased the theoretical population, cell viability, number of cilia and cell size of Tetrahymena thermophila in a time- and dose-dependent manner. Meanwhile, RNA-Seq analysis indicated that exposure to 4.26 mg/L TCEP significantly changed expression of 2932 genes (up-regulation: 1228; down-regulation: 1704). Of these, expressions of 9, 10 and 17 genes that were enriched in soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) interaction in vesicular transport, proteasome and endocytosis pathway respectively were down-regulated. Data collected during this study suggested that exposure to high concentrations of TCEP might affect growth and reproduction of Tetrahymena thermophila through down-regulating transcriptional levels of genes encoding proteins associated with vesicle trafficking, proteasome and endocytosis.

中文翻译：

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磷酸三（2-氯乙基）酯（TCEP）对嗜热四膜膜虫嗜热菌的生长，繁殖和基因转录的影响。

作为典型的有机磷阻燃剂，已在各种环境介质中广泛检测到磷酸三（2-氯乙基）酯（TCEP）。已经研究了TCEP对脊椎动物的毒性，但迄今为止尚不知道其对低营养水平物种的潜在影响。在这项研究中，通过表型观察，转录组测序分析和实时定量PCR检测，评价了TCEP对水生原生动物四膜虫的毒性作用和毒性作用的分子机制。暴露于0.044、0.411或4.26 mg / L TCEP达5天以时间和剂量依赖性方式降低了理论种群，细胞活力，纤毛数量和嗜热四膜膜虫的细胞大小。同时，RNA-Seq分析表明暴露于4。26 mg / L TCEP显着改变了2932个基因的表达（上调：1228；下调：1704）。其中，分别在囊泡转运，蛋白酶体和内吞途径中富含可溶的N-乙基马来酰亚胺敏感性因子附着蛋白受体（SNARE）相互作用的9、10和17个基因的表达下调。这项研究期间收集的数据表明，暴露于高浓度的TCEP可能通过下调编码与囊泡运输，蛋白酶体和胞吞作用有关的蛋白质的基因的转录水平来影响嗜热四膜膜菌的生长和繁殖。蛋白酶体和内吞途径分别下调。这项研究期间收集的数据表明，暴露于高浓度的TCEP可能通过下调编码与囊泡运输，蛋白酶体和胞吞作用有关的蛋白质的基因的转录水平来影响嗜热四膜膜菌的生长和繁殖。蛋白酶体和内吞途径分别下调。这项研究期间收集的数据表明，暴露于高浓度的TCEP可能通过下调编码与囊泡运输，蛋白酶体和胞吞作用有关的蛋白质的基因的转录水平来影响嗜热四膜膜菌的生长和繁殖。