Deoxyribonucleic acid relatedness of some menaquinone-producing Flavobacterium and Cytophaga strains.

Nine menaquinone-forming strains of the Flavobacterium--Cytophaga complex with DNA base compositions between 35 and 45 moles percent guanine-plus-cytosine were investigated for genome sizes and DNA relatedness by DNA:DNA hybridization in vitro, using the optically recorded initial reassociation kinetics. Two strains representing C. hutchinsonii and C. marinoflava proved to be related on the 50 percent binding level, i.e. on a level of DNA relatedness commonly found within well-classified conventional genera of bacteria. Strains of C. johnsonae, F. heparinum, F. meningosepticum, F. odoratum, F. pectinovorum, and an unnamed Flavobacterium--Cytophaga strain were found to be interrelated, and linked to the genus Cytophaga, on the 30, or 20 percent binding levels, respectively. These findings indicate that the organisms in question are related to Cytophaga. They therefore should be transferred into the family Cytophagaceae.