Institute of Biological and Environmental Sciences, University of Aberdeen, UK.
ISME J. 2011 Jun;5(6):1067-71. doi: 10.1038/ismej.2010.191. Epub 2011 Jan 13.
The first step of nitrification, oxidation of ammonia to nitrite, is performed by both ammonia-oxidising archaea (AOA) and ammonia-oxidising bacteria (AOB) in soil, but their relative contributions to ammonia oxidation and existence in distinct ecological niches remain to be determined. To determine whether available ammonia concentration has a differential effect on AOA and AOB growth, soil microcosms were incubated for 28 days with ammonium at three concentrations: native (control), intermediate (20 μg NH(4)(+)-N per gram of soil) and high (200 μg NH(4)(+)-N per gram of soil). Quantitative PCR demonstrated growth of AOA at all concentrations, whereas AOB growth was prominent only at the highest concentration. Similarly, denaturing gradient gel electrophoresis (DGGE) analysis revealed changes in AOA communities at all ammonium concentrations, whereas AOB communities changed significantly only at the highest ammonium concentration. These results provide evidence that ammonia concentration contributes to the definition of distinct ecological niches of AOA and AOB in soil.
硝化作用的第一步是氨氧化为亚硝酸盐，这一过程既可以由氨氧化古菌（AOA）完成，也可以由氨氧化细菌（AOB）完成，但它们对氨氧化的相对贡献以及在不同生态位中的存在仍有待确定。为了确定可利用的氨浓度是否对 AOA 和 AOB 的生长有不同的影响，将土壤微宇宙在三种浓度的铵（天然（对照）、中间（20μgNH4（+）-N 每克土壤）和高（200μgNH4（+）-N 每克土壤）下培养 28 天。定量 PCR 表明 AOA 在所有浓度下均有生长，而 AOB 仅在最高浓度下生长明显。同样，变性梯度凝胶电泳（DGGE）分析表明，在所有铵浓度下 AOA 群落都发生了变化，而 AOB 群落仅在最高铵浓度下发生了显著变化。这些结果提供了证据表明，氨浓度有助于确定土壤中 AOA 和 AOB 的不同生态位。
