Microbial Genome Sequencing: The Complete Genome Sequence of a Mini Consortium of Marine Ammonia Oxidizers

氨在海洋、淡水、土壤和大气中含量丰富，是微生物和植物可利用氮的主要来源，而微生物和植物通过自身的消耗为动物提供氮。另一方面，氨被认为是最丰富的神经毒素，它存在于我们呼吸的空气中。因此，了解氨消耗的自然机制是维持地球宜居环境的关键。路易斯维尔大学（University of Louisville）的马丁？基因组研究所的John Heidelberg，伍兹霍尔海洋研究所的Karen Casciotti和普林斯顿大学的Bess Ward，对两种在海洋氮循环中起关键作用的变形菌的全基因组进行了测序。这两种细菌在海洋中具有相似的生态生理功能，即将氨转化为亚硝酸盐，并产生最终将被循环利用为良性氮气的含氮气体。所研究的两种海洋细菌在分类上属于不同的细菌类别；因此，它们的基因组可能包含不同的硝化活性分子碱基。因此，解开这些细菌的基因组成将为我们提供大量的见解，能够在这些细菌中进化了数十亿年的氨降解分子机制的多样性。将这种复杂的基因组信息与淡水或土壤中氨氧化剂的基因组信息进行比较，将使未来的科学项目能够设计出改进的技术策略，以控制人类活动产生的氨的去除，并确定控制这些氨氧化细菌的目标，这些细菌的存在是不受欢迎的（例如在饮用水生产设施中）。通过这项拨款资助的工作将涉及本科生和研究生的培训。

Ammonia is abundant in the oceans, in freshwater, soils and the atmosphere and represents the prime resource of usable nitrogen for microorganisms and plants, which provide nitrogen to animals through their consumption. On the other hand, ammonia is considered the most abundant neurotoxin that is present everywhere in the air that we breathe. Therefore, the understanding of mechanisms naturally involved in the consumption of ammonia is key to maintaining a hospitable planet Earth. A grant has been awarded to Dr. Martin G. Klotz of the University of Louisville, in collaboration with Drs. John Heidelberg of The Institute for Genome Research, Karen Casciotti of the Woods Hole Oceanographic Institute, and Bess Ward of Princeton University, to sequence the complete genomes of two proteobacteria that are key players in the marine nitrogen cycle. Both bacteria carry out a similar ecophysiological function in the oceans namely the conversion of ammonia to nitrite and the production of nitrogenous gases that - eventually - will be recycled to benign nitrogen gas. The two researched marine bacteria belong taxonomically to different classes of bacteria; hence their genomes likely contain different molecular bases for nitrification activities. Thus, the unraveling of the genetic make-up of these bacteria will provide us a great deal of insight into the diversity of molecular mechanisms capable of ammonia degradation that have evolved over billions of years in these bacteria. A comparison of this complex genomic information with that from ammonia-oxidizers that function in freshwater or soils will allow future scientific projects to design improved technological strategies for controlled removal of ammonia generated by human activities as well as the identification of targets for the control of such ammonia-oxidizing bacteria where their presence is undesirable (such as in drinking-water production facilities). Work funded through this grant will involve the training of undergraduate and graduate students.