美国加州理工学院Jared R. Leadbetter团队提出锰氧化能够引起细菌化学自养。这一研究成果于2020年7月15日发表在《自然》上。
他们提炼出一种富集培养，该培养表现出依赖于Mn（II）氧化的指数增长到两种微生物物种的共培养。氧化需要在允许的温度下使细菌存活，从而导致与细胞相关的氧化锰小结节的产生。该培养物的主要成员（他们将其命名为“ Candidatus Manganitrophus noduliformans”）隶属于硝化螺菌门（也称为硝化螺菌），但与已知的硝化螺菌和钩端螺旋体关系较远。
他们分离出少数菌种，即一种不会单独氧化Mn（II）的β变形杆菌，并将其命名为石绿假单胞菌。稳定同位素探测显示13CO2固定到细胞生物质中，这依赖于Mn（II）的氧化。转录组学分析揭示了将细胞外锰氧化与有氧能量守恒和自养二氧化碳固定结合的候选途径。这些发现扩展了已知的供给生命的无机代谢多样性，并完成了锰的生物地球化学能循环，该循环可能与其他主要的全球元素循环有关。
研究人员表示，锰是地球上最丰富的元素之一。长期以来，理论上已经有人对锰的氧化进行了理论研究（尚未证明），以促进化学自养微生物的生长。
附：英文原文
Title: Bacterial chemolithoautotrophy via manganese oxidation
Author: Hang Yu, Jared R. Leadbetter
Issue&Volume: 2020-07-15
Abstract: Manganese is one of the most abundant elements on Earth. The oxidation of manganese has long been theorized1—yet has not been demonstrated2,3,4—to fuel the growth of chemolithoautotrophic microorganisms. Here we refine an enrichment culture that exhibits exponential growth dependent on Mn(II) oxidation to a co-culture of two microbial species. Oxidation required viable bacteria at permissive temperatures, which resulted in the generation of small nodules of manganese oxide with which the cells associated. The majority member of the culture—which we designate ‘Candidatus Manganitrophus noduliformans’—is affiliated to the phylum Nitrospirae (also known as Nitrospirota), but is distantly related to known species of Nitrospira and Leptospirillum. We isolated the minority member, a betaproteobacterium that does not oxidize Mn(II) alone, and designate it Ramlibacter lithotrophicus. Stable-isotope probing revealed 13CO2 fixation into cellular biomass that was dependent upon Mn(II) oxidation. Transcriptomic analysis revealed candidate pathways for coupling extracellular manganese oxidation to aerobic energy conservation and autotrophic CO2 fixation. These findings expand the known diversity of inorganic metabolisms that support life, and complete a biogeochemical energy cycle for manganese5,6 that may interface with other major global elemental cycles.
DOI: 10.1038/s41586-020-2468-5
Source: https://www.nature.com/articles/s41586-020-2468-5
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
