Glöckner F O, Babenzien H D, Amann R
Max-Planck-Institut für marine Mikrobiologie, Bremen, Germany.
Appl Environ Microbiol. 1998 May;64(5):1895-901. doi: 10.1128/AEM.64.5.1895-1901.1998.
An enrichment of the neuston bacterium Nevskia ramosa was investigated by the cultivation-independent rRNA approach. N. ramosa was first described by Famintzin in 1892 as a rod-shaped, slightly bent bacterium forming typical flat rosettes on the surface of shallow freshwater habitats by unilateral slime formation. PCR in combination with cloning and sequencing was used for retrieving 21 partial and 5 nearly full-length 16S rRNA sequences forming three tight clusters. In situ hybridization with rRNA-targeted oligonucleotide probes allowed us to assign the three sequence clusters to three distinct bacterial populations abundant in the enrichment. The two probes that unambiguously identified the N. ramosa morphotype were derived from a 16S rRNA sequence that had similarities of 87.9 to 88.9% to the rRNA sequences of the most closely related group in the database, Xanthomonas sp. and relatives. N. ramosa currently is the only representative of an independent, deep branch of the gamma subclass of the class Proteobacteria. The two other populations abundant in the enrichment were affiliated with the alpha subclass of the class Proteobacteria. They were most closely related to Blastobacter sp. (97.2% similarity) and Mycoplana bullata (97.6% similarity) and might represent new species in the respective genera.
通过不依赖培养的rRNA方法对漂浮细菌拉氏涅夫斯基菌（Nevskia ramosa）的富集情况进行了研究。拉氏涅夫斯基菌于1892年由法明津首次描述，是一种杆状、略弯曲的细菌，通过单侧形成黏液在浅淡水生境表面形成典型的扁平莲座状。聚合酶链式反应（PCR）结合克隆和测序用于获取21个部分16S rRNA序列和5个近乎全长的16S rRNA序列，这些序列形成了三个紧密的簇。使用针对rRNA的寡核苷酸探针进行原位杂交，使我们能够将这三个序列簇归属于富集中大量存在的三个不同细菌种群。明确鉴定拉氏涅夫斯基菌形态型的两个探针源自一个16S rRNA序列，该序列与数据库中最密切相关的类群——黄单胞菌属（Xanthomonas sp.）及其亲缘种的rRNA序列相似度为87.9%至88.9%。拉氏涅夫斯基菌目前是变形菌纲γ亚类一个独立深分支的唯一代表。富集中大量存在的另外两个种群隶属于变形菌纲α亚类。它们与芽生杆菌属（Blastobacter sp.）（相似度97.2%）和泡状枝动菌（Mycoplana bullata）（相似度97.6%）关系最为密切，可能代表各自属中的新物种。
