Total DNA restriction pattern and quinone composition of members of the family Ectothiorhodospiraceae

Total DNA restriction pattern analysis was employed to study the genomic similarities among fifteen strains belonging to the family Ectothiorhodospiraceae. UPGMA analysis produced clusters of electrophoretic restriction patterns corresponding to the species distribution. Two strains were separated from the respective clusters of strains belonging to the same species. The determination of the quinone composition showed a clear separation between moderately and extremely halophilic strains of the family Ectothiorhodospiraceae and was also useful for the differentiation of the species. Strain EST8, which has already been described, without assigning it to a species, was shown to share some similarities with E. marismortui on the basis of both restriction fingerprint and quinone content. Our data show that a thorough study of a large number of strains is necessary to obtain a more precise description of the taxonomic structure of the family Ectothiorhodospiraceae.