Identification of Retinoic Acid Receptor Agonists in Sewage Treatment Plants

详细信息    查看全文

• 作者：Huajun Zhen ; Xiaoqin Wu ; Jianying Hu ; Yang Xiao ; Min Yang ; Junji Hirotsuji ; Jun-ichi Nishikawa ; Tsuyoshi Nakanishi ; Michihiko Ike
• 刊名：Environmental Science & Technology
• 出版年：2009
• 出版时间：September 1, 2009
• 年：2009
• 卷：43
• 期：17
• 页码：6611-6616
• 全文大小：229K
• 年卷期：v.43,no.17(September 1, 2009)
• ISSN：1520-5851

文摘

Retinoic acid receptor (RAR) agonists are speculated to be one possible cause for the widely observed frog deformities in North America, although little is known about the specific RAR agonists in aquatic environments. We identified the specific RAR agonists in sewage treatment plants (STPs) and receiving rivers using an RAR yeast two-hybrid bioassay. Water samples were extracted by solid-phase extract cartridges, which were successively eluted by hexane, ethyl acetate, and methanol for bioassay. Among the three fractions, the ethyl acetate fraction showed the highest RAR agonistic activities. The bioassay-derived activity, expressed as all-trans-retinoic acid (all-trans-RA) equivalents (ATRA-EQ) were 10.9 ± 2.2 and 1.7 ± 1.0 ng/L in the STP influents and effluents, respectively, while the ATRA-EQs were as high as 7.1 and 8.3 ng/L in the two rivers receiving STP effluents. Following a two-step fractionation using high-performance liquid chromatography and ultra-performance liquid chromatography (UPLC) directed by the bioassay, two bioactive fractions were obtained from Gaobeidian STP influent and all-trans-4-oxo-RA (4.7−10.4 ng/L in influents, <0.2−0.9 ng/L in effluents) and 13-cis-4-oxo-RA (2.3−7.1 ng/L in influents, <0.4−1.1 ng/L in effluents) were identified in these fractions with UPLC-MS/MS. The EC₅₀ for all-trans-4-oxo-RA or 13-cis-4-oxo-RA relative to that of all-trans-RA in exhibiting RARα agonistic activity was calculated to be 3.87 and 0.46, respectively.