Stevens Heike, Stübner Matthias, Simon Meinhard, Brinkhoff Thorsten
Institute for Chemistry and Biology of the Marine Environment ICBM, University of Oldenburg, P.O. Box 2503, D-26111 Oldenburg, Germany.
FEMS Microbiol Ecol. 2005 Nov 1;54(3):351-65. doi: 10.1016/j.femsec.2005.04.008.
Bacteria of the phyla Proteobacteria and Bacteroidetes are known to be the most prominent heterotrophic organisms in marine surface waters. In order to investigate the occurrence of these phyla in a coastal environment, the tidal flat ecosystem German Wadden Sea, we analyzed a clone library of PCR-amplified and sequenced 16S rRNA gene fragments and isolated 46 new strains affiliated with these phyla from the water column with various polymers and complex media as substrates. The phylogenetic affiliation of these strains was analyzed on the basis of sequenced 16S rRNA gene fragments. Subsequently, a comprehensive phylogenetic analysis of Proteobacteria and Bacteroidetes including available sequences from oxic habitats of earlier studies of this ecosystem was performed. Sequences of the earlier studies were derived from isolation approaches and from denaturing gradient gel electrophoresis (DGGE) analyses of environmental samples and high dilution steps of MPN (most probable number) cultures. The majority of the 265 sequences included in this analysis affiliated with alpha-Proteobacteria (45.3%), gamma-Proteobacteria (31.7%), and Bacteroidetes (16.2%). Almost 7% belong to the delta-Proteobacteria and several of these clones affiliated with the Myxococcales, a group comprising obligate aerobic organisms. Within the alpha- and gamma-Proteobacteria specific clusters were identified including isolates from high dilution steps of dilution cultures and/or clones from the clone library or DGGE gels, implying a high abundance of some of these organisms. Within the gamma-Proteobacteria a new cluster is proposed, which consists of marine surface-attached organisms. This SAMMIC (Surface Attached Marine MICrobes) cluster comprises only uncultured phylotypes and exhibits a global distribution. Overall, the analysis indicates that Proteobacteria and Bacteroidetes of the Wadden Sea have a surprisingly high diversity, presumably a result of the signature of this ecosystem as a melting pot at the land-sea interface and comprising a great habitat variety.
变形菌门和拟杆菌门的细菌是海洋表层水体中最为突出的异养生物。为了研究这些菌门在沿海环境——德国瓦登海潮间带生态系统中的出现情况，我们分析了PCR扩增并测序的16S rRNA基因片段的克隆文库，并以各种聚合物和复杂培养基为底物，从水柱中分离出46株隶属于这些菌门的新菌株。基于测序的16S rRNA基因片段分析了这些菌株的系统发育归属。随后，对变形菌门和拟杆菌门进行了全面的系统发育分析，其中包括该生态系统早期研究中来自有氧生境的可用序列。早期研究的序列来自分离方法、环境样品的变性梯度凝胶电泳（DGGE）分析以及MPN（最可能数）培养物的高稀释步骤。该分析中包含的265个序列大部分隶属于α-变形菌纲（45.3%）、γ-变形菌纲（31.7%）和拟杆菌门（16.2%）。近7%属于δ-变形菌纲，其中一些克隆隶属于粘球菌目，该类群包括专性需氧生物。在α-和γ-变形菌纲中鉴定出了特定的簇，包括稀释培养物高稀释步骤中的分离物和/或克隆文库或DGGE凝胶中的克隆，这意味着其中一些生物具有高丰度。在γ-变形菌纲中提出了一个新的簇，它由海洋表面附着生物组成。这个SAMMIC（表面附着海洋微生物）簇仅包含未培养的系统发育型，并且呈现全球分布。总体而言，分析表明瓦登海的变形菌门和拟杆菌门具有惊人的高多样性，这可能是该生态系统作为陆海界面的大熔炉且包含多种生境的特征所致。
