Garcia-Pichel F, Prufert-Bebout L, Muyzer G
Max Planck Institute for Marine Microbiology, Bremen, Germany.
Appl Environ Microbiol. 1996 Sep;62(9):3284-91. doi: 10.1128/aem.62.9.3284-3291.1996.
We used micromanipulation to isolate from their environment representative samples of seven geographically distant field populations fitting the description of Microcoleus chthonoplastes (a cyanobacterium) and obtained seven corresponding cultured strains. Samples of both field populations and cultures were phenotypically characterized by microscale techniques, and their partial 16S rRNA gene sequences were compared by denaturing gradient gel electrophoresis and in some cases by sequencing. All field populations and strains were phenotypically extremely coherent, and their 16S rRNA sequences were indistinguishable by DGGE. The sequences determined were identical or virtually identical. Thus, M. chthonoplastes represents a single, well-delimited taxon with a truly cosmopolitan distribution. Comparison with three culture collection strains originally assigned to M. chthonoplastes revealed that strain PCC 7420 belongs to the same tightly delimited group, both phenotypically and in 16S rRNA gene sequence, but that strains SAG 3192 and 10mfx do not.
我们采用显微操作技术，从七个地理上相距遥远、符合厚壁微鞘藻（一种蓝细菌）描述的野外种群的环境中分离出代表性样本，并获得了七个相应的培养菌株。通过微观技术对野外种群和培养物样本进行了表型特征分析，并通过变性梯度凝胶电泳对它们的部分16S rRNA基因序列进行了比较，在某些情况下还进行了测序。所有野外种群和菌株在表型上极其一致，通过变性梯度凝胶电泳无法区分它们的16S rRNA序列。所测定的序列完全相同或几乎完全相同。因此，厚壁微鞘藻代表了一个单一的、界限明确的分类单元，具有真正的全球分布。与最初归为厚壁微鞘藻的三个培养保藏菌株进行比较发现，菌株PCC 7420在表型和16S rRNA基因序列上均属于同一个界限紧密的类群，但菌株SAG 3192和10mfx不属于。
