Nakagawa Y, Yamasato K
Institute of Applied Microbiology, University of Tokyo, Japan.
J Gen Microbiol. 1993 Jun;139 Pt 6:1155-61. doi: 10.1099/00221287-139-6-1155.
To clarify the intra- and intergeneric relationships of the genus Cytophaga, 16S rRNA sequences and respiratory isoprenoid quinones were determined for the type strains of the 21 validly published species and one isolate in the genus Cytophaga. The sequence analysis revealed extreme heterogeneity of this genus, which diverged into nine distinct lines of descent. Each lineage of Cytophaga was characterized by possessing either menaquinone-6 (MK-6) or MK-7. The MK-6-possessing species were located in the two lineages that were remote from MK-7 species. One of the MK-6 lineages was composed only of terrestrial species and the other only of marine species. Flavobacterium aquatile, the type species of the genus Flavobacterium, was located in the MK-6 terrestrial lineage. The terrestrial Cytophaga species with MK-6 should be transferred to the genus Flavobacterium. The marine facultative anaerobes with MK-7 were located in the bacteroides branch, and possessed signature sequences with features intermediate between the bacteroides and the flavobacteria subdivisions. Cytophaga hutchinsonii, the type species of the genus Cytophaga, had a close relationship only with Cytophaga aurantiaca. The genus Cytophaga should be restricted to these two cellulose-degrading species. The genus Cytophaga is so heterogeneous that it should be divided into several genera and higher taxa in accordance with the phylogenetic relationships.
为阐明噬纤维菌属内和属间的关系，测定了噬纤维菌属中21个有效发表种的模式菌株和1个分离株的16S rRNA序列及呼吸类异戊二烯醌。序列分析揭示了该属的极端异质性，其分化为9个不同的谱系。噬纤维菌的每个谱系的特征是含有甲基萘醌-6（MK-6）或MK-7。含有MK-6的物种位于与含有MK-7的物种相距较远的两个谱系中。其中一个含有MK-6的谱系仅由陆生物种组成，另一个仅由海洋物种组成。水生黄杆菌，黄杆菌属的模式种，位于含有MK-6的陆生谱系中。含有MK-6的陆生噬纤维菌物种应转移到黄杆菌属。含有MK-7的海洋兼性厌氧菌位于拟杆菌分支中，并具有介于拟杆菌和黄杆菌亚群之间特征的特征序列。哈氏噬纤维菌，噬纤维菌属的模式种，仅与橙色噬纤维菌关系密切。噬纤维菌属应仅限于这两个纤维素降解物种。噬纤维菌属非常异质，应根据系统发育关系分为几个属和更高的分类单元。
