Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri
Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri
复制标题
DOI：
10.1128/aem.00895-14
复制
发表时间：
2014-08-01
影响因子：
4.4
通讯作者：
Lovley, Derek R.
中科院分区：
文献类型：
--
作者：
Rotaru, Amelia-Elena;Shrestha, Pravin Malla;Lovley, Derek R.
直接种间电子转移（DIET）是产甲烷菌群落中一种潜在的有效的互养形式，但对具有DIET能力的产甲烷菌的多样性知之甚少。在与金属还原地杆菌共培养的情况下评估了巴氏甲烷八叠球菌参与饮食的能力。共培养物形成的聚集体，通过DIET共享电子在乙醇到甲烷的化学计量转化。不能用菌毛蛋白缺陷的G.这表明沿沿着皮利的长程电子传递对于DIET是重要的。颗粒活性炭的添加使菌毛蛋白缺陷型G.金属还原菌分离物与M共享电子。barkeri，表明这种导电材料可以替代皮利促进DIET。当M. barkeri与产H-2、不能进行DIET、M.巴克氏菌利用H-2作为电子供体，但代谢甲醇假单胞菌产生的乙酸盐很少。这表明，H-2，而不是来自饮食的电子，抑制乙酸代谢。甲醇假单胞菌barkeri共培养物没有聚集，表明，与饮食，密切的身体接触是没有必要的种间H-2转移。M. barkeri是第二个发现通过DIET接受电子的产甲烷菌，并且是第一个已知能够使用H-2或来自DIET的电子进行CO2还原的产甲烷菌。此外，M。巴氏杆菌在遗传上易于处理，使其成为阐明产甲烷菌与其他细胞进行生物电连接的机制的模式生物。
Direct interspecies electron transfer (DIET) is potentially an effective form of syntrophy in methanogenic communities, but little is known about the diversity of methanogens capable of DIET. The ability of Methanosarcina barkeri to participate in DIET was evaluated in coculture with Geobacter metallireducens. Cocultures formed aggregates that shared electrons via DIET during the stoichiometric conversion of ethanol to methane. Cocultures could not be initiated with a pilin-deficient G. metallireducens strain, suggesting that long-range electron transfer along pili was important for DIET. Amendments of granular activated carbon permitted the pilin-deficient G. metallireducens isolates to share electrons with M. barkeri, demonstrating that this conductive material could substitute for pili in promoting DIET. When M. barkeri was grown in coculture with the H-2-producing Pelobacter carbinolicus, incapable of DIET, M. barkeri utilized H-2 as an electron donor but metabolized little of the acetate that P. carbinolicus produced. This suggested that H-2, but not electrons derived from DIET, inhibited acetate metabolism. P. carbinolicus-M. barkeri cocultures did not aggregate, demonstrating that, unlike DIET, close physical contact was not necessary for interspecies H-2 transfer. M. barkeri is the second methanogen found to accept electrons via DIET and the first methanogen known to be capable of using either H-2 or electrons derived from DIET for CO2 reduction. Furthermore, M. barkeri is genetically tractable, making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.