Isolation and Genomic Characterization of 'Desulfuromonas soudanensis WTL', a Metal- and Electrode-Respiring Bacterium from Anoxic Deep Subsurface Brine.
Isolation and Genomic Characterization of 'Desulfuromonas soudanensis WTL', a Metal- and Electrode-Respiring Bacterium from Anoxic Deep Subsurface Brine.
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DOI：
10.3389/fmicb.2016.00913
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发表时间：
2016
影响因子：
5.2
通讯作者：
Bond DR
中科院分区：
文献类型：
--
作者：
Badalamenti JP;Summers ZM;Chan CH;Gralnick JA;Bond DR
Soudan地下铁矿位于地表以下713米的深度，横切了一个巨大的太古宙（2.7 Ga）带状铁地层，为了解陆地深层生物圈提供了一个非常容易接近的窗口。尽管有机碳含量有限，但在27层勘探钻孔中不断冒出的可能古老的缺氧盐水中存在金属还原微生物群落。我们使用原位沉积的石墨电极作为诱饵，从+0.24 V（相对于标准氢电极）的醋酸盐三电极生物反应器中，通过电化学富集和分离出一种新的嗜盐还原性铁δ蛋白酶杆菌“Desulfuromonas soudanensis”菌株WTL。循环伏安法表明，D。soudanensis的释放电子氧化还原电位大约100 mV更积极比淡水模型表面隔离核废料旁边sulfurreducens,表明其胞外呼吸调高等潜在的电子受体。' D。soudanensis’含有一个3,958,620 bp的环状基因组，使用单分子实时（SMRT）测序reads组装完成，编码一个完整的TCA循环，38个推测的多血红素c型细胞色素，其中一个含有69个血红素结合基元，以及一个LuxI/LuxR群体感应盒，产生一个未知的n -酰基高丝氨酸内酯。另一种细胞色素预计位于假定的前噬菌体内，表明水平基因转移在金属还原剂的呼吸灵活性中起作用。D的分离。Soudanensis强调了基于电极的方法在广泛栖息地富集稀有金属还原剂的实用性。
Reaching a depth of 713 m below the surface, the Soudan Underground Iron Mine (Soudan, MN, USA) transects a massive Archaean (2.7 Ga) banded iron formation, providing a remarkably accessible window into the terrestrial deep biosphere. Despite organic carbon limitation, metal-reducing microbial communities are present in potentially ancient anoxic brines continuously emanating from exploratory boreholes on Level 27. Using graphite electrodes deposited in situ as bait, we electrochemically enriched and isolated a novel halophilic iron-reducing Deltaproteobacterium, ‘Desulfuromonas soudanensis’ strain WTL, from an acetate-fed three-electrode bioreactor poised at +0.24 V (vs. standard hydrogen electrode). Cyclic voltammetry revealed that ‘D. soudanensis’ releases electrons at redox potentials approximately 100 mV more positive than the model freshwater surface isolate Geobacter sulfurreducens, suggesting that its extracellular respiration is tuned for higher potential electron acceptors. ‘D. soudanensis’ contains a 3,958,620-bp circular genome, assembled to completion using single-molecule real-time (SMRT) sequencing reads, which encodes a complete TCA cycle, 38 putative multiheme c-type cytochromes, one of which contains 69 heme-binding motifs, and a LuxI/LuxR quorum sensing cassette that produces an unidentified N-acyl homoserine lactone. Another cytochrome is predicted to lie within a putative prophage, suggesting that horizontal gene transfer plays a role in respiratory flexibility among metal reducers. Isolation of ‘D. soudanensis’ underscores the utility of electrode-based approaches for enriching rare metal reducers from a wide range of habitats.