2009 Fiscal Year Final Research Report

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

Research Project

Project/Area Number	19780240
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Boundary agriculture
Research Institution	Nagaoka National College of Technology
Principal Investigator	TASAKI Yuji Nagaoka National College of Technology, 物質工学科, 准教授 (90390434)
Project Period (FY)	2007 – 2009
Keywords	環境 / 水資源 / 遺伝子 / 応用微生物 / 酵素 / バイオテクノロジー
Research Abstract	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.