Reigstad Laila J, Richter Andreas, Daims Holger, Urich Tim, Schwark Lorenz, Schleper Christa
Department of Biology, Center for Geobiology, University of Bergen, Bergen, Norway.
FEMS Microbiol Ecol. 2008 May;64(2):167-74. doi: 10.1111/j.1574-6941.2008.00466.x. Epub 2008 Mar 18.
Archaea have been detected recently as a major and often dominant component of the microbial communities performing ammonia oxidation in terrestrial and marine environments. In a molecular survey of archaeal ammonia monooxygenase (AMO) genes in terrestrial hot springs of Iceland and Kamchatka, the amoA gene encoding the alpha-subunit of AMO was detected in a total of 14 hot springs out of the 22 investigated. Most of these amoA-positive hot springs had temperatures between 82 and 97 degrees C and pH range between 2.5 and 7. In phylogenetic analyses, these amoA genes formed three independent lineages within the known sequence clusters of marine or soil origin. Furthermore, in situ gross nitrification rates in Icelandic hot springs were estimated by the pool dilution technique directly on site. At temperatures above 80 degrees C, between 56 and 159 mumol NO(3)(-) L(-1) mud per day was produced. Furthermore, addition of ammonium to the hot spring samples before incubation yielded a more than twofold higher potential nitrification rate, indicating that the process was limited by ammonia supply. Our data provide evidence for an active role of archaea in nitrification of hot springs in a wide range of pH values and at a high temperature.
最近发现古菌是陆地和海洋环境中进行氨氧化的微生物群落的主要且通常占主导地位的组成部分。在对冰岛和堪察加半岛陆地温泉中古菌氨单加氧酶（AMO）基因的分子调查中，在所调查的22个温泉中，共有14个温泉检测到了编码AMOα亚基的amoA基因。这些amoA阳性温泉大多温度在82至97摄氏度之间，pH值在2.5至7之间。在系统发育分析中，这些amoA基因在已知的海洋或土壤来源序列簇中形成了三个独立的谱系。此外，通过现场池稀释技术直接估算了冰岛温泉中的原位总硝化速率。在温度高于80摄氏度时，每天每立方米泥浆产生56至159微摩尔硝酸根离子。此外，在培养前向温泉样品中添加铵会使潜在硝化速率提高两倍以上，这表明该过程受氨供应限制。我们的数据为古菌在广泛pH值和高温的温泉硝化作用中发挥的积极作用提供了证据。
