Abstract：
The process of anaerobic ammonium oxidation by nitrite (anammox) is a globally essential part of N cycle. To date, 8 Candidatus genera and more than 22 species of anammox bacteria have been discovered in various anthropogenic and natural habitats, including nitrogen-polluted aquifers. In this work, anammox bacteria were detected for the first time in the groundwater ecosystem with high anthropogenic nitrogen pollution (up to 1760 mg NO3--N/L and 280 mg NH4+-N/L) and low year-round temperature (7-8 °C) in the zone of a uranium sludge repository. Further metagenomic analysis resulted in retrieval of metagenome-assembled genomes of 4 distinct anammox bacteria: a new genus named Ca. Frigussubterria, new species in Ca. Kuenenia, and two strains of a new species in Ca. Scalindua. Analysis of the genomes revealed essential genes involved in anammox metabolism. Both strains of Ca. Scalindua chemeplantae had a high copy number of genes encoding the cold shock proteins CspA/B, which can also function as an antifreeze protein (CspB). Ca. Kuenenia glazoviensis and Ca. Frigussubterria udmurtiae were abundant in less N-polluted site, while Ca. Scalindua chemeplantae inhabited both sites. Genes for urea utilization, reduction of insoluble Fe2O3 or MnO2, assimilatory sulfate reduction, reactive oxygen detoxification, nitrate reduction to ammonium, and putatively arsenate respiration were found. These findings enrich knowledge of the functional and phylogenetic diversity of anammox bacteria and improve understanding of the nitrogen cycle in polluted aquifers.
摘要：
亚硝酸盐（anammox）的厌氧氨氧化过程是氮循环的全球重要组成部分。迄今为止,在各种人为和自然栖息地中发现了8个念珠菌属和22种以上的厌氧氨氧化细菌，包括氮污染的含水层。在这项工作中,首次在人为氮污染高（高达1760mgNO3--N/L和280mgNH4-N/L）和全年温度低（7-8°C）的地下水生态系统中检测到厌氧氨氧化细菌。铀污泥库的区域。进一步的宏基因组分析导致恢复了4种不同的厌氧氨氧化细菌的宏基因组组装的基因组：一种名为Ca的新属。Frigussubterra，Ca中的新物种。Kuenenia,和Ca中的两个新物种。Scalindua.基因组分析揭示了参与厌氧氨氧化代谢的必需基因。两种菌株的Ca。Scalinduachemeplantae具有高拷贝数的编码冷休克蛋白CspA/B的基因，它也可以作为抗冻蛋白（CspB）。Ca.甘草和钙。在N污染较少的地方，Frigussubterra泥木科很丰富，而Ca。Scalinduachemeplantae居住在两个地点。尿素利用基因，不溶性Fe2O3或MnO2的还原，同化硫酸盐还原，活性氧解毒，硝酸盐还原成铵，发现了砷酸盐呼吸。这些发现丰富了厌氧氨氧化细菌功能和系统发育多样性的知识，并增进了对污染含水层中氮循环的了解。
