Analyses of acidophilic bacterial communities and environmental changes using microcosms

1.片沼湖是一个强酸性湖，于2004年4月至2006年12月进行了调查。湖水的热分布呈二分型。在4月至8月的分层期间，没有硫化氢的好氧水检测到的上层，而缺氧和积累的硫化氢是突出的下层。在秋季环流期间，整个水体中没有硫化氢的存在，水体处于氧化状态。2.利用两种属特异的寡核苷酸探针，结合荧光原位杂交技术，分别对嗜酸菌属和嗜酸硫杆菌属的生物量进行了测定。分层期以嗜酸菌属（Acidiphilium）为主，循环期以嗜酸菌属和嗜酸菌属为主。这些微宇宙在以下条件下培养：1）黑暗条件，2） ...更多信息 低温，3）低溶解氧，4）亚铁添加，5）葡萄糖添加，6）硫代硫酸盐添加，和7）对照。荧光原位杂交分析表明，在低温和硫代硫酸盐处理1周后，微宇宙中嗜酸硫杆菌数量增加，嗜酸菌数量减少。4.变性梯度凝胶电泳（DGGE）分析结果表明，微宇宙中的嗜酸硫杆菌（Acidithiobacillus）由喜温嗜酸杆菌（At.caldus）和阿尔伯特嗜酸杆菌（At.albertensis）两个种组成，嗜酸菌（Acidiphilium）主要由嗜酸嗜酸杆菌（A.acidophilum）组成。DGGE未检测到其他细菌属。虽然嗜酸菌属被认为是片沼湖等酸性环境的主要代表，但在秋季循环期间，酸性硫杆菌属可在硫化物供应或低水温条件下增殖。少

1.The Lake Katanuma, a strongly acid lake, was surveyed during April 2004 to December 2006. The thermal pattern in the lake water showed dimictic. During the stratification period from April to August, oxic water with no hydrogen sulfide was detected in the epilimnion, whereas oxygen depletion and accumulated hydrogen sulfide were prominent in the hypolimnion. Oxic conditions and no hydrogen sulfide were observed in the entire water column during the autumn circulation period.2.Two genus specific oligonucleotide probes were used with fluorescent in situ hybridization (FISH) to measure the biomasses of the genera Acidiphilium and Acidithiobacillus, respectively. The genus Acidiphilium dominated the bacteria community at the stratification period, while both genera dominated at the circulation period.3.We made the microcosms from the lake water of the stratification and circulation periods, respectively. These microcosms were cultured under the following conditions ; 1)dark condition, 2) … More low temperature, 3)low dissolved oxygen, 4)ferrous addition, 5)glucose addition, 6)thiosulfate addition, and 7)control. FISH analysis indicated that the increased abundant of Acidithiobacillus and the decrease of Acidiphilium were observed after 1 week in the microcosms treated with the thiosulfate addition and low temperature. In the microcosms of the other conditions, the biomasses of two genera have not changed.4.Denaturing gradient gel electrophoresis (DGGE) analysis of the microbial community in the microcosms revealed that the genus Acidithiobacillus was consisting of two species, At.caldus and At.albertensis and the genus Acidiphilium was mainly composed of A.acidophilum. Other bacteria genera were not detected by DGGE. Although Acidiphilium species are considered the major representatives of the acidic environments such as the Lake Katanuma, the genus Acidithiobacillus could proliferate under the conditions of sulfide supply or low water temperature during autumn circulation period. Less