Systematics of streptomycetes from Antarctic soil

Twenty-four soil samples were collected from the Vestfold Hills and Mirror Peninsula in the Antarctic. Fifty-two hyphal actinomycetes were isolated from six of the 24 soils, using micromanipulation. Five of the six actinomycete bearing soils were from sites associated with moss or lichen but no other correlation between the presence of viable actinomycetes and soils characteristics was determined. Fatty acid and isoprenoid quinone profiles indicated that each of the 52 isolates could be accommodated within the genus Streptomyces. Phenotypic characters, fatty acid profiles, and 16S-23Sr RNA intrageneric spacer patterns were compared among all isolates. As a result of these comparisons the 52 isolates were placed into five groups, each group being comprised of strains of a single species. Representative strains were chosen from each of the five groups for further study. Partial 16S rRNA sequence comparison and DNA:DNA hybridization studies indicated that each of the five representative strains was a separate species. These studies also showed that two of the representative strains were known species, Streptomyces analatus (DSMZ strain 40361) and Streptomyces vinaceus (DSMZ strain 40257). Two other representative strains were not identified as known species, but extensive DNA:DNA hybridization studies are needed to determine their taxonomy accurately within the currently accepted definition of a species. One of the representative strains was identified as a new species. The diversity of actinomycetes in Antarctic soils is relatively low compared to that in temperate soils. However, the distribution of Antarctic actinomycete strains and their location near moss and lichen beds suggested that these strains were able to survive in the Antarctic and to grow there for at least part of the Antarctic year. An attempt was made to differentiate between the five representative strains using Amplified Ribosomal DNA Restriction Analysis (ARDRA). However, the ARDRA technique was only effective if differences in 16S rRNA sequences were known so that appropriate enzymes could be selected. Differentiating between strains on the basis of 16S-23Sr RNA intrageneric spacer patterns was a faster and more accurate way of grouping closely related isolates. Antibiotic compounds were produced by two of the Antarctic strains, indicating the potential of the Antarctic microbiota for biotechnological exploitation