Guan Ling, Shiiya Ayaka, Hisatomi Shihoko, Fujii Kunihiko, Nonaka Masanori, Harada Naoki
Center for Fostering Innovative Leadership, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata, 950-2181, Japan.
Biodegradation. 2015 Feb;26(1):29-38. doi: 10.1007/s10532-014-9713-2. Epub 2014 Sep 18.
Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions.
二苯胂酸（DPAA）常作为二苯氯胂或二苯氰胂的有毒中间代谢产物被发现，这两种物质曾作为化学战剂生产，并在两次世界大战后被埋入土壤。在我们之前的研究中（Guan等人，《危险材料杂志》241 - 242:355 - 362，2012年），在施加硫酸盐和碳源后，土壤中DPAA的厌氧转化得到增强，主要代谢产物为二苯硫胂酸（DPTAA）。本研究旨在分离和鉴定负责DPAA代谢的厌氧土壤微生物。首先，我们获得了四个微生物群落，在培养4周后，它们能够以超过80%的高转化率将DPAA转化为DPTAA。对从这些群落构建的细菌16S rRNA基因克隆文库进行测序，结果显示所有阳性群落都含有产乙酸脱硫肠状菌。相反，在未显示出DPAA还原的阴性群落中，证实不存在硫酸盐还原菌特有的异化亚硫酸盐还原酶基因（dsrAB）。最后，从一个阳性群落中分离出了能将DPAA转化为DPTAA的菌株DEA14。根据部分16S rDNA序列分析，该分离株被归类为产乙酸脱硫肠状菌。在已知的硫酸盐还原细菌菌株耐氧脱硫弧菌JCM 12613(T)的纯培养物中也进行了DPAA的硫代反应。这些事实表明，硫酸盐还原菌是在厌氧条件下负责将DPAA转化为DPTAA的微生物。
