Emended descriptions of Lactobacillus sake (Katagiri, Kitahara, and Fukami) and Lactobacillus curvatus (Abo-Elnaga and Kandler): Numerical classification revealed by protein fingerprinting and identification based on biochemical patterns and DNA-DNA hybridizations

A former subgenus of the genus Lactobacillus, ''Streptobacterium,'' comprises a wide range of species, including the so-called ''atypical streptobacteria,'' which includes the Lactobacillus sake-lactobacillus curvatus group. Various identification systems and differentiation criteria for L. sake and L. curvatus have been described previously and are well established. The phenotypic diversity within these two species was the reason for comparing phenotypic variations with DNA homology data. Previously described biotypes oft. sake (Katagiri, Kitahara, and Fukami) and L. curvatus (Abo-Elnaga and Kandler) were the basis for selecting strains. Strains of all known biotypes of these species were examined to determine their biochemical reactions, their physiological growth characteristics, their total soluble protein contents as determined by a pattern analysis in which native polyacrylamide gel electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis with colloidal Coomassie blue and silver diamine staining were used, and their levels of DNA homology as determined by DNA-DNA hybridization experiments. All of the phenotypic analyses revealed a diversity within the taxa, whereas the DNA-DNA hybridization analysis revealed that the level of genomic homogeneity within each species was relatively high. The phenotypic diversity and genomic homogeneity which we observed allowed us to describe subgroups of L. sake and L. curvatus. The descriptions of L. sake and L. curvatus are emended accordingly. These subgroups which we describe may be the basis for defining subspecies within these two species.