Immobilization of Shewanella oneidensis MR-1 in diffusive gradients in thin films for determining metal bioavailability.
Immobilization of Shewanella oneidensis MR-1 in diffusive gradients in thin films for determining metal bioavailability.
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DOI：
10.1016/j.chemosphere.2015.06.018
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发表时间：
2013-09
期刊：
影响因子：
8.8
通讯作者：
P. Baker;Christer Högstrand;J. Lead;R. Pickup;Hao Zhang
中科院分区：
文献类型：
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作者：
P. Baker;Christer Högstrand;J. Lead;R. Pickup;Hao Zhang
土壤中金属的生物有效性评价对于模拟金属毒性对周围生态系统的影响具有重要意义。目前基于扩散梯度薄膜（DGT）和凝胶集成微电极的方法在其可用性和灵敏度方面受到限制。为了解决这一问题，将厌氧铁还原菌希瓦氏菌（Shewanella oneidensis）掺入琼脂糖薄层中，以取代通常存在于DGT中的聚丙烯酰胺凝胶，以形成生物动员DGT（BMDGT）。存活力分析显示，16-35%的细胞在BMDGT内保持存活，这取决于在有/没有金属的20小时内的培养条件。当将在Luria肉汤（LB）中生长的细胞掺入BMDGT中并在厌氧条件下部署时，在标准化金属溶液中部署BMDGT与无细胞BMDGT表现出显著差异。这些BMDGT在赤铁矿中的部署显示BMDGT和含有热杀死细胞的BMDGT之间没有显着差异。热杀死的细胞是否保留影响生物利用度的能力尚不确定。这是第一个研究如何将微生物，如金属还原菌，S。oneidensis，可能会影响金属的流动性。
Assessing metal bioavailability in soil is important in modeling the effects of metal toxicity on the surrounding ecosystem. Current methods based on diffusive gradient thin films (DGTs) and Gel-Integrated Microelectrode are limited in their availability and sensitivity. To address this, Shewanella oneidensis, an anaerobic iron reducing bacterium, was incorporated into a thin layer of agarose to replace the polyacrylamide gel that is normally present in DGT to form biologically mobilizing DGT (BMDGT). Viability analysis revealed that 16–35% of the cells remained viable within the BMDGTs depending on the culturing conditions over a 20 h period with/without metals. Deployment of BMDGTs in standardized metal solutions showed significant differences to cell-free BMDGTs when cells grown in Luria Broth (LB) were incorporated into BMDGTs and deployed under anaerobic conditions. Deployment of these BMDGTs in hematite revealed no significant differences between BMDGTs and BMDGTs containing heat killed cells. Whether heat killed cells retain the ability to affect bioavailability is uncertain. This is the first study to investigate how a microorganism that was incorporated into a DGT device such as the metal reducing bacteria, S. oneidensis, may affect the mobility of metals.