Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 6, 1996
Publication Date: N/A
Interpretive Summary: Verticillate streptomycetes are filamentous bacteria that have a distinctive "barbed-wire" like spore arrangement and are found infrequently in temperate to tropical soils. Many of these microorganisms produce potent antibiotics including several with antitumor activity. Identification of these bacteria to the species level is not easy but is required when searching for new antibiotic or antitumor compounds. The current classification of these microorganisms, using characteristics based on their appearance and nutritional requirements, was suspected of being invalid, and a study was done of the genetic relatedness among most of the verticillate species. It was shown that grouping of species based on genetic (DNA) similarity does not agree with the currently accepted groupings based on computer assisted statistical analysis of a large number of physiological and morphological properties. The classification scheme for this group of bacteria must be now be revised to be valid and useful to other scientists.
Technical Abstract: DNA relatedness among 35 strains of Streptomyces species originally classified in the genus Streptoverticillium was determined spectrophotometrically. The strains represent eight of the phenotypic cluster groups described for Streptoverticillium in Bergey's Manual of Systematic Bacteriology. Average linkage clustering of the DNA relatedness data resulted in 20 clusters at greater than 70 percent DNA relatedness, including 14 single-member clusters. Several species could be reduced to synonymy based on DNA homology but not generally equivalent to the clustering suggested by phenotypic numerical taxonomy.