Basic Research on the Development of Detoxification Techniques of Endocrine Disrupting Chemicals, Short Ethoxy Chain-Alkylphenols

烷基酚聚氧乙烯醚（APEO）是一类非离子表面活性剂，经细菌生物降解后产生的短乙氧基链烷基酚类物质是潜在的内分泌干扰物。为了阐明APEOs的生物降解机理，我们采用转座子标签法从恶臭假单胞菌S-5中分离出APEOs降解相关基因，并对其DNA序列进行分析。通过将转座子Tn 5插入恶臭假单胞菌S-5中构建了约11，000个转座子突变体。分离出17个不能代谢OPEO的突变体，即OPEO降解基因破坏物。测定了插入转座子破坏的基因的DNA序列。相似性搜索结果表明，这些基因编码的17个蛋白质与酰基辅酶A合成酶、伴侣蛋白、NADH醌氧化还原酶等具有较高的氨基酸序列相似性。T424基因仅在OPEO上生长的细胞中表达，而其他基因在葡萄糖上以及在OPEO上生长的细胞中表达。

Alkylphenol polyethoxylates (APEOs) belonging to a group of nonionic surfactants are biodegraded by bacteria and then short ethoxy chain-alkylphenols which are potential endocrine disrupters are produced. In this study, to elucidate the biodegradation mechanism of APEOs, we isolated genes that were involved in biodegradation of octylphenol polyethoxylate (OPEO), a kind of APEOs, from OPEO degrader Pseudomonas putida S-5 by transposon tagging and analyzed their DNA sequences. Approximately 11,000 transposon mutants were constructed by insertion of transposon Tn5 into P.putida S-5. Seventeen mutants that are not able to metabolize OPEO, namely OPEO-degradation gene disruptants, were isolated. DNA sequences of the genes disrupted by insertion of transposon were determined. A similarity search showed that 17 proteins encoded by the genes have high amino acid sequence similarity to acyl-CoA synthetase, chaperone protein, NADH quinone oxidoreductase, etc. Gene expression of 9 genes in P.putida S-5 cells grown on different carbon source (OPEO or glucose) was analyzed by RT-PCR. T424 gene was expressed only in cells grown on OPEO, while the other genes were expressed in cells grown on glucose as well as on OPEO.