Lu Shipeng, Peiffer Stefan, Lazar Cassandre Sara, Oldham Carolyn, Neu Thomas R, Ciobota Valerian, Näb Olga, Lillicrap Adam, Rösch Petra, Popp Jürgen, Küsel Kirsten
Chair of Aquatic Geomicrobiology, Friedrich Schiller University Jena, Jena, Germany.
The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
Environ Microbiol Rep. 2016 Feb;8(1):58-67. doi: 10.1111/1758-2229.12351. Epub 2015 Dec 21.
We investigated the microbial community compositions in two sediment samples from the acidic (pH ∼3) and hypersaline (>4.5% NaCl) surface waters, which are widespread in Western Australia. In West Dalyup River, large amounts of NaCl, Fe(II) and sulfate are brought by the groundwater into the surface run-off. The presence of K-jarosite and schwertmannite minerals in the river sediments suggested the occurrence of microbial Fe(II) oxidation because chemical oxidation is greatly reduced at low pH. 16S rRNA gene diversity analyses revealed that sequences affiliated with an uncultured archaeal lineage named Aplasma, which has the genomic potential for Fe(II) oxidation, were dominant in both sediment samples. The acidophilic heterotrophs Acidiphilium and Acidocella were identified as the dominant bacterial groups. Acidiphilium strain AusYE3-1 obtained from the river sediment tolerated up to 6% NaCl at pH 3 under oxic conditions and cells of strain AusYE3-1 reduced the effects of high salt content by forming filamentous structure clumping as aggregates. Neither growth nor Fe(III) reduction by strain AusYE3-1 was observed in anoxic salt-containing medium. The detection of Aplasma group as potential Fe(II) oxidizers and the inhibited Fe(III)-reducing capacity of Acidiphilium contributes to our understanding of the microbial ecology of acidic hypersaline environments.
我们研究了来自西澳大利亚广泛分布的酸性（pH值约为3）和高盐度（>4.5% NaCl）地表水的两个沉积物样本中的微生物群落组成。在西达利普河中，大量的氯化钠、亚铁离子和硫酸根由地下水带入地表径流。河流沉积物中钾铁矾和施韦特曼石矿物的存在表明发生了微生物亚铁离子氧化作用，因为在低pH值条件下化学氧化作用会大大降低。16S rRNA基因多样性分析显示，与一个名为Aplasma的未培养古菌谱系相关的序列在两个沉积物样本中均占主导地位，该谱系具有亚铁离子氧化的基因组潜力。嗜酸异养菌嗜酸菌属和嗜酸单胞菌属被鉴定为主要细菌类群。从河流沉积物中获得的嗜酸菌属菌株AusYE3- 在有氧条件下于pH值为3时能耐受高达6%的氯化钠，并且AusYE3- 菌株的细胞通过形成丝状结构聚集成团来降低高盐含量的影响。在缺氧含盐培养基中未观察到AusYE3- 菌株的生长或铁（III）还原作用。Aplasma菌群作为潜在亚铁离子氧化菌的检测以及嗜酸菌属抑制铁（III）还原的能力有助于我们理解酸性高盐环境的微生物生态学。
