Rahalkar M, Deutzmann J, Schink B, Bussmann I
Universität Konstanz, Fachbereich Biologie, LS Mikrobielle Okologie, Fach M 654, D-78457 Constance, Germany.
Appl Environ Microbiol. 2009 Jan;75(1):119-26. doi: 10.1128/AEM.01350-08. Epub 2008 Nov 7.
The abundances and activities of aerobic methane-oxidizing bacteria (MOB) were compared in depth profiles of littoral and profundal sediments of Lake Constance, Germany. Abundances were determined by quantitative PCR (qPCR) targeting the pmoA gene and by fluorescence in situ hybridization (FISH), and data were compared to methane oxidation rates calculated from high-resolution concentration profiles. qPCR using type I MOB-specific pmoA primers indicated that type I MOB represented a major proportion in both sediments at all depths. FISH indicated that in both sediments, type I MOB outnumbered type II MOB at least fourfold. Results obtained with both techniques indicated that in the littoral sediment, the highest numbers of methanotrophs were found at a depth of 2 to 3 cm, corresponding to the zone of highest methane oxidation activity, although no oxygen could be detected in this zone. In the profundal sediment, highest methane oxidation activities were found at a depth of 1 to 2 cm, while MOB abundance decreased gradually with sediment depth. In both sediments, MOB were also present at high numbers in deeper sediment layers where no methane oxidation activity could be observed.
对德国康斯坦茨湖沿岸和深底沉积物深度剖面中的需氧甲烷氧化细菌（MOB）的丰度和活性进行了比较。通过靶向pmoA基因的定量PCR（qPCR）和荧光原位杂交（FISH）测定丰度，并将数据与根据高分辨率浓度剖面计算出的甲烷氧化速率进行比较。使用I型MOB特异性pmoA引物的qPCR表明，I型MOB在所有深度的两种沉积物中均占主要比例。FISH表明，在两种沉积物中，I型MOB的数量至少是II型MOB的四倍。两种技术获得的结果表明，在沿岸沉积物中，在2至3厘米深度处发现了最高数量的甲烷营养菌，这对应于甲烷氧化活性最高的区域，尽管在该区域未检测到氧气。在深底沉积物中，在1至2厘米深度处发现了最高的甲烷氧化活性，而MOB丰度随沉积物深度逐渐降低。在两种沉积物中，在更深的沉积层中也存在大量MOB，在这些沉积层中未观察到甲烷氧化活性。
