U.S.-Korea Cooperative Research: Carbon Monoxide as a Substrate for Microbial Maintenance

细菌在一氧化碳（CO）的全球预算中起着重要作用。土壤和水生系统水柱中大部分未知的细菌种群每年氧化数百太克，约占估计的年大气通量的10%-20%。尽管它们具有生物地球化学意义，但人们对原位活跃的CO氧化群体的身份、它们的系统发育和生理多样性以及CO作为其基本代谢需要的底物的重要性知之甚少。一氧化碳氧化剂。很明显，高浓度的CO （1000 ppm）可以作为实验室培养的细胞碳和能量的唯一来源，但环境CO浓度很少达到或超过几个ppm。细菌很容易使用这样的浓度，但它们是否足以显著地促进细胞代谢需要？该奖项支持Gary M. King教授和他在缅因大学的一名研究生与韩国延世大学的Y. M. Kim博士及其研究小组就这一问题进行合作研究。他们将评估低的生态现实的CO浓度对两种常见的土壤分离物——耻垢分枝杆菌和日本慢生根瘤菌的生长和生存的意义。该合作项目将包括对低浓度CO在与其土壤自然动态相关的条件下促进CO氧化剂生存和活力的能力的分子和生理分析。Kim博士在CO氧化细菌（包括分枝杆菌）的分子生物学、生理学和生长以及CO脱氢酶的遗传学和生物化学表征方面拥有丰富的经验，而King博士在研究微生物微量气体利用的生态生理学和生物地球化学、近环境CO分析的分析技术和仪器方面拥有丰富的经验，并在微观世界和气体流动系统的设计方面拥有专业知识。更广泛的意义研究结果将显著提高我们对微生物CO代谢的生态生理学的理解，特别是在现实世界水平上。这些信息是预测对气候、土地利用和水生系统富营养化等长期区域尺度扰动的潜在反应的重要因素。这项工作将包括美国和韩国研究生的交流，他们将从学习新的研究技术和文化经验中受益。国际研究经验可能会扩大美国学生在金博士小组的未来研究机会。在这一研究伙伴关系中，技术和方法的交流将增强两个实验室在解决影响大气成分的微生物群生态生理学方面的热门问题方面的能力。

0342779KingBacteria play an important role in the global budget of carbon monoxide (CO). Largely unknown bacterial populations in soils and the water column of aquatic systems oxidize hundreds of teragrams per year, or about 10%-20% of the estimated annual flux to the atmosphere. In spite of their biogeochemical significance, relatively little is known about the identity of CO-oxidizing populations active in situ, their phylogenic and physiological diversity or the importance of CO as substrate for their basic metabolic needs. of CO oxidizers. It is clear that CO at high concentrations ( 1000 ppm) can serve as a sole source of cell carbon and energy for laboratory-grown cultures, but ambient CO concentrations seldom reach or exceed a few ppm. Bacteria readily use such concentrations, but are they sufficient to contribute significantly to cellular metabolic needs?This award supports Professor Gary M. King and one of his graduate students at the University of Maine to collaborate in research on this question with Dr. Y. M. Kim and his research group from Yonsei University in Korea. They will evaluate the significance of low, ecologically realistic CO concentrations for growth and survival of two common soil isolates, Mycobacterium smegmatis and Bradyrhizobium japonicum. This collaborative project will include both molecular and physiological analyses of the ability of CO at low concentrations to promote the survival and viability of CO oxidizers under conditions relevant to their natural dynamics in soils. Dr. Kim has extensive experience with the molecular biology, physiology and growth of CO-oxidizing bacteria, including mycobacteria, and characterization of the genetics and biochemistry of CO dehydrogenase, while Dr. King has extensive experience in studying the ecophysiology and biogeochemistry of microbial trace gas utilization, analytical techniques and instrumentation for near-ambient CO analyses, and expertise in the design of microcosms and gas flow systems for research. Broader significanceResults of the study will significantly improve our understanding of the ecophysiology of microbial CO metabolism, particularly at real-world levels. This information is an important factor in predicting potential responses to long-term, regional-scale disturbances in climate, land use and eutrophication of aquatic systems.The work will involve exchanges of both U.S. and Korean graduate students, who will benefit from learning new research techniques and from the cultural experience. The international research experience is likely to expand the future research opportunities of the US students in Dr. King's group. The exchange of techniques and methods in this research partnership will enhance the capabilities of both labs to address topical issues in the ecophysiology of microbial groups that affect atmospheric composition.