Seasonal dynamics of dimethylarsenic acid degrading bacteria dominated in Lake Kibagata
Seasonal dynamics of dimethylarsenic acid degrading bacteria dominated in Lake Kibagata
复制标题
DOI：
10.1080/01490450600761953
复制
发表时间：
2006-07-01
影响因子：
2.3
通讯作者：
Ueda, Kazumasa
中科院分区：
文献类型：
--
作者：
Maki, Teruya;Watarai, Hiroshi;Ueda, Kazumasa
有机砷化合物的降解过程对水环境中砷的循环有重要影响，并依赖于细菌的活性。2003年4月至12月，对木钵田湖中涉及二甲基胂酸（DMAA）降解的细菌种群进行了调查。在实验期间，未检测到甲基化砷，尽管无机砷浓度范围为3.4 nM至9.2 nM。此外，在木钵湖水样中，DMAA添加到25天，DMAA减少，而无机砷增加。这些事实表明，该细菌将甲基化砷转化为无机砷。事实上，使用最可能数（MPN）程序监测表明，DMAA降解细菌的细胞密度范围为41个细胞/ml至510个细胞/ml。为了确定DMAA降解菌的组成，共110个菌株获得的优势菌种进行了分析，通过限制性片段长度多态性（RFLP）分析的16 S rDNA。结果表明，110个菌株可分为12个类型，其中4个类型主要发生在春秋季，其余8个类型主要发生在夏季。110个菌株对DMAA的降解活性各不相同。特别是秋季的一些菌株往往表现出较高的降解活性。利用16 S rDNA系统发育分析表明，代表菌株形成了几个集群的革兰氏阳性菌群和变形菌亚门。不同组成的DMAA降解菌会随季节变化，以控制在木方的有机砷降解率。
Degradation processes of organoarsenic compounds significantly influence arsenic cycles in aquatic environments and would depend on the bacterial activities. The bacterial population involving dimethylarsinic acid (DMAA) degradation was investigated in Lake Kibagata from April to December in 2003. During the experimental period, the methylated arsenic was not detected, although the inorganic arsenic concentration ranged from 3.4 nM to 9.2 nM. Moreover, in the sample water of Lake Kibagata to which DMAA added, DMAA decreased while inorganic arsenic increased for 25 days. These facts suggested that the bacteria remineralized methylate arsenic species to inorganic arsenic. In fact, monitoring the use of Most Probable Number (MPN) procedure demonstrated that the DMAA-degrading bacteria exist at cell densities ranged from 41 cells/ml to 510 cells/ml. To determine the composition of DMAA-degrading bacteria, the total 110 isolates obtained as dominated bacterial species were analyzed by the restriction-fragment-length polymorphism (RFLP) analysis of 16S rDNA. As a result, total 110 isolates were classified into 12 types, of which 4 types dominated during the spring and/or fall seasons, and the rest 8 types dominated during summer season. DMAA degrading activities of the 110 isolates ranged at various degrees. Especially, the some isolates of fall season tend to show high degradation activities. The phylogenetic analysis using 16S rDNA revealed that the representative isolates formed several clusters in the gram-positive bacterial group and the proteobacteria subdivision. The diverse compositions of DMAA-degrading bacteria would seasonally change to control the rates of organoarsenic degradation in Kibagata.