Summary auto-generated
This study examined the phylogenetic relationships and taxonomic classification of bacteria in the genera Flavobacterium, Cytophaga, and Flexibacter using DNA-rRNA hybridization, G+C content analysis, fatty acid profiling, and protein electrophoresis. The researchers found that these three genera are highly polyphyletic, with species from Cytophaga and Flexibacter clustering with Flavobacterium aquatile, the type species of genus Flavobacterium. Because multiple Cytophaga and Flexibacter species isolated from soil and freshwater are phylogenetically and phenotypically closely related to F. aquatile, the authors proposed transferring seven validly described species to an emended Flavobacterium genus. These include F. columnare, F. fluvense, F. johnsoniae, F. pectinovorum, F. psychrophilum, F. saccharophilum, and F. succinicans. Additionally, they propose a new name, Flavobacterium hydatis, for the previously misclassified [Cytophaga] aquatilis. The emended genus comprises gram-negative, gliding, yellow-pigmented rods that decompose polysaccharides, are aerobic chemoorganotrophs, and occur in soil and freshwater. Three species are fish pathogens. An emended description of family Flavobacteriaceae is also provided.
Key findings
- Genera Cytophaga and Flexibacter are highly polyphyletic; most species are distantly related to their respective type species
- Seven misclassified species from Cytophaga and Flexibacter are transferred to an emended genus Flavobacterium based on phylogenetic and phenotypic similarity to F. aquatile
- Flavobacterium hydatis (basonym [Cytophaga] aquatilis) is proposed as a new combination for a species previously assigned to Cytophaga
- Emended Flavobacterium comprises gram-negative, gliding, yellow-pigmented rods that decompose polysaccharides but not cellulose, with G+C content 32-37 mol%
- Three Flavobacterium species are pathogenic for fish
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
The phylogenetic positions and G+C contents of most species belonging to the genera Flavobacterium, Cytophaga, and Flexibacter and several related taxa were determined. Most of the strains included in this study belong to rRNA superfamily V, as shown by DNA-rRNA hybridization data, but the three main genera are highly polyphyletic. Several so-called Cytophaga and Flexibacter species isolated from soil and freshwater cluster with the type species of the genus Flavobacterium, Flavobacterium aquatile, and with Flavobacterium branchiophilum. The fatty acid and protein profiles of members of this group of organisms were determined. We provide an emended description of the genus Flavobacterium and propose new combinations for the following 7 of the 10 validly described species included in this genus: Flavobacterium columnare, Flavobacterium flevense, Flavobacterium johnsoniae (we also correct the specific epithet of this taxon), Flavobacterium pectinovorum, Flavobacterium psychrophilum, Flavobacterium saccharophilum, and Flavobacterium succinicans. A new name Flavobacterium hydatis, is proposed for [Cytophaga] aquatilis Strohl and Tait 1978. The emended genus Flavobacterium contains bacteria that have the following main characteristics: gram-negative rods that are motile by gliding, produce yellow colonies on agar, are chemoorganotrophs and aerobes, decompose several polysaccharides but not cellulose, and are widely distributed in soil and freshwater habitats. Three Flavobacterium species are pathogenic for fish. The G+C contents of Flavobacterium DNAs range from 32 to 37 mol%. An emended description of the family Flavobacteriaceae is also provided.