In situ imaging of Sulfobacillus thermosulfidooxidans on pyrite under conditions of variable pH using tapping mode atomic force microscopy
In situ imaging of Sulfobacillus thermosulfidooxidans on pyrite under conditions of variable pH using tapping mode atomic force microscopy
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DOI：
10.1016/j.procbio.2011.01.014
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发表时间：
2011-04-01
影响因子：
4.4
通讯作者：
Watling, H. R.
中科院分区：
文献类型：
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作者：
Becker, T.;Gorham, N.;Watling, H. R.
利用原位原子力显微镜（AFM）对附着在黄铁矿表面的嗜热氧化硫化杆菌细胞进行了成像。附着的细菌分散在小群体中，没有优选的方向或位点特异性偏好。研究了细胞在改变pH值时产生胞外聚合物（EPS）的重要性。细菌脱离或被逐出，并且没有检测到EPS在溶液中从pH 2.2快速降低至pH 1.0。相比之下，从pH 2.2至pH 1.4，观察到厚度增加的EPS层。在进一步酸化（pH 0.9）后，细胞没有被逐出，但EPS层的厚度立即减小，这归因于EPS网络内的聚合物链的结构重排。这表明细菌通过表达EPS来响应由酸度增加引起的压力。其作为对环境中不利条件的缓冲。黄铁矿表面的次生矿物形成（“规模”）被发现只在微生物的存在下形成，并最终覆盖黄铁矿表面。细菌细胞没有附着在鳞片表面。除垢后，在下层黄铁矿表面观察到与细菌细胞形状相似的蚀坑。(c)2011爱思唯尔有限公司保留所有权利。
Sulfobacillus thermosulfidooxidans cells attached to pyrite surfaces were imaged using in situ tapping mode atomic force microscopy (AFM). The attached bacteria were dispersed in small groups without preferred orientation or site specific preference. The importance of extracellular polymeric substances (EPS) production by cells upon changing pH was examined. Bacteria detached or were dislodged and no EPS was detected for a rapid decrease from pH 2.2 to pH 1.0 in the solution. In contrast, a layer of EPS with increasing thickness was observed for a decrease from pH 2.2 to pH 1.4. Upon further acidification (pH 0.9) the cells were not dislodged but the thickness of the EPS layer decreased immediately, which is attributed to structural re-arrangements of the polymeric chains within the EPS network. This suggests that the bacteria respond to stress caused by increased acidity by expressing EPS. which acts as a buffer against unfavourable conditions in the environment. Secondary mineral formation ('scale') on the pyrite surface was found to form only in the presence of microorganisms and eventually covered the pyrite surface. Bacterial cells did not attach to the scale surface. Upon scale removal, etch pits with similar shape to bacterial cells were observed in the underlying pyrite surface. (c) 2011 Elsevier Ltd. All rights reserved.