Bacterial Manganese (II) Oxidation in the Guaymas Basin Hydrothermal Plume

热液喷口是溶解锰（II）的全球重要来源，锰是生物体必需的微量营养素，也是热液活动的有价值的示踪剂。在热液柱等含氧水体中，可溶性锰（II）最终被氧化为锰（III/IV）氧化物。这些“海洋清道夫”（Goldberg 1954）是一种活性极强的矿物质，可以隔离多种金属，并与多种无机和有机化合物进行氧化还原反应，因此在海洋地球化学中起着重要作用。细菌在热液喷口和其他环境中催化Mn（II）氧化为Mn(III/IV)，因此被认为是天然Mn（III/IV）氧化矿物形成的原因。尽管许多研究表明细菌对环境中观察到的锰的快速氧化率负责，但对所涉及的生物，锰生物矿化的机制和产物以及锰（II）氧化的生物学功能知之甚少。在这项研究中，来自加州大学圣地亚哥分校斯克里普斯海洋研究所的研究人员将确定Guaymas盆地（GB）喷口柱中负责Mn氧化的细菌群落，确定Mn氧化物生物矿化的分子机制和产物，并阐明最近在热液喷口附近分离的Mn氧化细菌中发现的核酮糖-1,5-二磷酸羧化酶（rubisco）基因的作用。利用细菌氧化分子生物学的新见解和先进的光谱技术，将研究GB热液柱中Mn氧化的机制和产物。分子探针将用于分析锰氧化基因的环境多样性和分布。将在一系列条件下测量GB羽流水中的Mn氧化率，以测试我们关于Mn氧化的特定分子机制的假设。x射线吸收光谱和同步辐射x射线衍射将用于表征天然锰氧化物和反应中间体以及由锰氧化分离物产生的产物。为了研究细菌锰氧化的功能，科学家们将研究最近从深海热液喷口分离出来的锰氧化细菌中参与自养碳固定（rubisco）的基因的作用。为了检测这些基因的表达，将对mn氧化细菌分离株进行实验室（生理学）实验和实地调查。

ABSTRACTOCE- 0352081Hydrothermal vents are a globally significant source of dissolved manganese (II), an essential micronutrient for organisms and a valuable tracer of hydrothermal activity. In oxic waters such as hydrothermal plumes, soluble Mn(II) is eventually oxidized to Mn(III/IV) oxides. These "scavengers of the sea" (Goldberg 1954) are highly reactive minerals that are known to sequester a variety of metals and participate in redox reactions with a wide range of inorganic and organic compounds, thus playing an important role in marine geochemistry. Bacteria catalyze the oxidation of Mn(II) to Mn(III/IV) at hydrothermal vents and other environments and are thus thought to be responsible for the formation of natural Mn(III/IV) oxide minerals. Although many studies have shown that bacteria are responsible for the rapid Mn oxidation rates observed in the environment, relatively little is known about the organisms involved, the mechanism(s) and products of Mn biomineralization, and the biological function of Mn(II) oxidation. In this study, researchers from the University of California- San Diego Scripps Institute of Oceanography will identify the bacterial community responsible for Mn oxidation in Guaymas Basin (GB) vent plumes, determine the molecular mechanism and products of Mn oxide biomineralization, and elucidate the role of ribulose-1,5-bisphosphate carboxylase (rubisco) genes recently found in Mn-oxidizing bacteria isolated near hydrothermal vents. The mechanism(s) and products of Mn oxidation in GB hydrothermal plumes will be investigated utilizing new insights into the molecular biology of bacterial oxidation and advanced spectroscopic techniques. Molecular probes will be designed to analyze the environmental diversity and distribution of genes involved in Mn oxidation. Mn oxidation rates will be measured in GB plume waters under a range of conditions designed to test our hypotheses concerning specific molecular mechanisms of Mn oxidation. X-ray absorption spectroscopy and synchrotron radiation X-ray diffraction will be used to characterize natural Mn oxides and reaction intermediates and products produced by Mn-oxidizing isolates. To investigate the function of bacterial Mn oxidation, the scientists will examine the role of genes involved in autotrophic carbon fixation (rubisco) in Mn oxidizing bacteria recently isolated from deep-sea hydrothermal vents. To detect expression of these genes both laboratory (physiology) experiments on Mn-oxidizing bacterial isolates and fieldwork will be performed.