School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0340, USA.
Environ Microbiol. 2010 Apr;12(4):938-50. doi: 10.1111/j.1462-2920.2009.02137.x. Epub 2010 Jan 18.
Recent voltammetric analyses indicate that Shewanella putrefaciens strain 200 produces soluble organic-Fe(III) complexes during anaerobic respiration of sparingly soluble Fe(III) oxides. Results of the present study expand the range of Shewanella species capable of producing soluble organic-Fe(III) complexes to include Shewanella oneidensis MR-1. Soluble organic-Fe(III) was produced by S. oneidensis cultures incubated anaerobically with Fe(III) oxides, or with Fe(III) oxides and the alternate electron acceptor fumarate, but not in the presence of O(2), nitrate or trimethylamine-N-oxide. Chemical mutagenesis procedures were combined with a novel MicroElectrode Screening Array (MESA) to identify four (designated Sol) mutants with impaired ability to produce soluble organic-Fe(III) during anaerobic respiration of Fe(III) oxides. Two of the Sol mutants were deficient in anaerobic growth on both soluble Fe(III)-citrate and Fe(III) oxide, yet retained the ability to grow on a suite of seven alternate electron acceptors. The rates of soluble organic-Fe(III) production were proportional to the rates of iron reduction by the S. oneidensis wild-type and Sol mutant strains, and all four Sol mutants retained wild-type siderophore production capability. Results of this study indicate that the production of soluble organic-Fe(III) may be an important intermediate step in the anaerobic respiration of both soluble and sparingly soluble forms of Fe(III) by S. oneidensis.
最近的伏安分析表明，腐败希瓦氏菌（Shewanella putrefaciens）菌株 200 在对难溶性三价铁氧化物进行厌氧呼吸时会产生可溶的有机铁（III）配合物。本研究的结果将能够产生可溶有机铁（III）配合物的希瓦氏菌种类的范围扩大到包括希瓦氏菌属（Shewanella）的一个种，即希瓦氏菌属（Shewanella）oneidensis MR-1。可溶有机铁（III）是由 S. oneidensis 培养物在厌氧条件下与三价铁氧化物或三价铁氧化物和替代电子受体延胡索酸盐共同孵育时产生的，但在存在氧气、硝酸盐或三甲胺-N-氧化物时不会产生。化学诱变程序与新型微电极筛选阵列（MESA）相结合，以确定四个（指定为 Sol）突变体在厌氧呼吸过程中无法产生可溶有机铁（III）。这四个 Sol 突变体中的两个在可溶铁（III）柠檬酸和铁（III）氧化物上的厌氧生长都有缺陷，但仍然保留了在七种替代电子受体上生长的能力。可溶有机铁（III）的产生速率与 S. oneidensis 野生型和 Sol 突变株的铁还原速率成正比，并且所有四个 Sol 突变体都保留了野生型铁载体的产生能力。本研究的结果表明，可溶有机铁（III）的产生可能是 S. oneidensis 对可溶和难溶形式的三价铁进行厌氧呼吸的一个重要中间步骤。
