Electrophoretic profiles of soluble proteins derived from seven strains of
Bran ham el la ca tarr halis, N e isseria perflava, Neisseria sicca, an d the psy c hr o p hile ,Micrococcus cry ophilus, were compared. The profiles produced from the strains of Branhamella catarrhalis showed a marked similarity except for that of strain Ne4 (ATCC 23246) which was distinguishable from those of the other six strains. Species-specific profiles demonstrating no characteristic species-related banding patterns were obtained from the soluble proteins of N. perflava and N. sicca.The profile from M. cryophilus was likewise specific and species distinct from those of the other bacteria tested. Identification of natural taxonomic interrelationships between these bacteria as determined by the electrophoretic separation of proteins are discussed.The problematical status in the taxonomy of the gram-negative cocci Neisseria catarrhalis (1,5 ) and Micrococcus cryophilus (14) has been described, and a suggestion for their possible taxonomic relatedness has been proposed (1 6). Catlin and Cunningham (5) reported N. catarrhalis to be an atypical neisseria based on its deoxyribonucleic acid (DNA) base composition of 4 1% guanine plus cytosine (G + C) compared to 50% G + C for other neisseriae and by its negligible interspecies transformation frequencies. However, high transformation frequencies between strains of this species were reported (6). Later evidence demonstrated a phenotypic homogeneity among the strains of N . catarrhalis (1) and little hybridization of the DNA from this species with the DNA from other genetically related species of the genus (1 1, 12). These facts led Catlin (4) to propose that the currently recognized species N. catarrhalis be taxonomically relocated to the new genus Branhamella gen. nov., within the family Neisseriaceae. The type species is designated as B. catarrhah comb. nov. This designation will be used throughout this paper.The psychrophile M. cryophilus has become a taxonomic enigma within the genus Micrococcus since Mazenec et al. (14) reported on the cytological characterization of this bacterium. This psychrophile was described as possessing a capsule, its cells arranged pre- dominantly in pairs and tetrads, and displaying a gram-negative appearance in its cell wall ultrastructure. These properties were not shown to be characteristic for the type species, M. luteus. Recently, Sleytr and Kocur (16) described similar observations in the fine structure of M. cryophilus. Moreover, these investigators recognized a close similarity in the fine structure of M. cryophilus to that described earlier (10) for various neisseriae, but especially B. catarrhalis. Accordingly, it was proposed (1 6 ) that M. cryophilus be taxonomically reassigned among the nonsaccharolytic Neisseriaceae. This, together with similarities in DNA base contents of 41% G + C for both M. cryophilus (2) and B.catarrhah (1, 3, 5), was viewed as further evidence t o advance this taxonomic shift.The purpose of this study was to determine wheth...