Brümmer I H M, Felske A D M, Wagner-Döbler I
German Research Centre for Biotechnology, Department of Microbiology, Mascheroder Weg 1, D-38124 Braunschweig, Germany.
Appl Environ Microbiol. 2004 Sep;70(9):5094-101. doi: 10.1128/AEM.70.9.5094-5101.2004.
Cell counts of planctomycetes showed that there were high levels of these organisms in the summer and low levels in the winter in biofilms grown in situ in two polluted rivers, the Elbe River and the Spittelwasser River. In this study 16S rRNA-based methods were used to investigate if these changes were correlated with changes in the species composition. Planctomycete-specific clone libraries of the 16S rRNA genes found in both rivers showed that there were seven clusters, which were distantly related to the genera Pirellula, Planctomyces, and Gemmata. The majority of the sequences from the Spittelwasser River were affiliated with a cluster related to Pirellula, while the majority of the clones from the Elbe River fell into three clusters related to Planctomyces and one deeply branching cluster related to Pirellula. Some clusters also contained sequences derived from freshwater environments worldwide, and the similarities to our biofilm clones were as high as 99.8%, indicating the presence of globally distributed freshwater clusters of planctomycetes that have not been cultivated yet. Community fingerprints of planctomycete 16S rRNA genes were generated by temperature gradient gel electrophoresis from Elbe River biofilm samples collected monthly for 1 year. Sixteen bands were identified, and for the most part these bands represented organisms related to the genus Planctomyces. The fingerprints showed that there was strong seasonality of most bands and that there were clear differences in the summer and the winter. Thus, seasonal changes in the abundance of Planctomycetales in river biofilms were coupled to shifts in the community composition.
对浮霉菌的细胞计数表明，在易北河和施皮特尔瓦瑟河这两条受污染河流中就地生长的生物膜里，这些微生物的数量在夏季较高，冬季较低。在本研究中，基于16S rRNA的方法被用于调查这些变化是否与物种组成的变化相关。在两条河流中发现的16S rRNA基因的浮霉菌特异性克隆文库显示有七个簇，它们与皮氏菌属、浮霉属和芽殖菌属关系较远。施皮特尔瓦瑟河的大多数序列属于与皮氏菌相关的一个簇，而易北河的大多数克隆则分为与浮霉属相关的三个簇和与皮氏菌相关的一个深度分支簇。一些簇还包含来自世界各地淡水环境的序列，与我们生物膜克隆的相似度高达99.8%，这表明存在尚未培养的全球分布的淡水浮霉菌簇。通过温度梯度凝胶电泳从易北河生物膜样本中生成了浮霉菌16S rRNA基因的群落指纹图谱，这些样本是在一年的时间里每月采集的。共鉴定出16条带，其中大部分条带代表与浮霉属相关的生物。指纹图谱显示，大多数条带具有很强的季节性，夏季和冬季有明显差异。因此，河流生物膜中浮霉菌目丰度的季节性变化与群落组成的变化相关。
