Respiration and growth of Shewanella decolorationis S12 with an azo compound as the sole electron acceptor
Respiration and growth of Shewanella decolorationis S12 with an azo compound as the sole electron acceptor
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以偶氮化合物为唯一电子受体的脱色希瓦氏菌 S12 的呼吸和生长
DOI：
10.1128/aem.01415-06
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发表时间：
2007-01-01
影响因子：
4.4
通讯作者：
Sun, Guoping
中科院分区：
文献类型：
--
作者：
Hong, Yiguo;Xu, Meiying;Sun, Guoping
研究了脱色希瓦氏菌S12通过不同给电子体的氧化与异化偶氮还原相耦合获得生长能量的能力。该微生物可以利用甲酸酯、乳酸酯、丙酮酸酯或H-2作为电子供体来还原多种偶氮染料。此外，菌株S12在限定的培养基中竞争还原2.0 mM苋菜后，生长到最大密度为3.0 × 10(7)个细胞/ ml。当苋菜和甲酸盐分别作为唯一的电子受体和供体时，随着时间的推移，这伴随着4.0 mM甲酸盐的化学测量消耗，这表明微生物偶氮还原是一个电子传递过程，这种电子传递可以产生能量来支持生长。对S12的纯化膜质、周质和细胞质部分进行了分析，但只有膜质部分能够以甲酸盐、乳酸盐、丙酮酸盐或H-2为电子供体还原偶氮染料。5 μ M Cu2+离子、200 μ M双藻醇、100 μ M青藻素和100 μ M甲屈酮的存在抑制了全细胞和纯化膜组分厌氧偶氮还原活性，表明脱氢酶、细胞色素和甲基萘醌是偶氮还原必不可少的电子传递组分。这些结果证明了微生物厌氧偶氮还原与电子传递链有关，并表明异化偶氮还原是微生物厌氧呼吸的一种形式。这些发现不仅扩大了已知的微生物能量守恒的潜在电子受体的数量，而且阐明了微生物厌氧偶氮还原的机制。
The ability of Shewanella decolorationis S12 to obtain energy for growth by coupling the oxidation of various electron donors to dissimilatory azoreduction was investigated. This microorganism can reduce a variety of azo dyes by use of formate, lactate, pyruvate, or H-2 as the electron donor. Furthermore, strain S12 grew to a maximal density of 3.0 x 10(7) cells per ml after compete reduction of 2.0 mM amaranth in a defined medium. This was accompanied by a stoichiometric consumption of 4.0 mM formate over time when amaranth and formate were supplied as the sole electron acceptor and donor, respectively, suggesting that microbial azoreduction is an electron transport process and that this electron transport can yield energy to support growth. Purified membranous, periplasmic, and cytoplasmic fractions from S12 were analyzed, but only the membranous fraction was capable of reducing azo dyes with formate, lactate, pyruvate, or H-2 as the electron donor. The presence of 5 mu M Cu2+ ions, 200 mu M dicumarol, 100 mu M stigmatellin, and 100 mu M metyrapone inhibited anaerobic azoreduction activity by both whole cells and the purified membrane fraction, showing that dehydrogenases, cytochromes, and menaquinone are essential electron transfer components for azoreduction. These results provide evidence that the microbial anaerobic azoreduction is linked to the electron transport chain and suggest that the dissimilatory azoreduction is a form of microbial anaerobic respiration. These findings not only expand the number of potential electron acceptors known for microbial energy conservation but also elucidate the mechanisms of microbial anaerobic azoreduction.