IDENTIFICATION OF PHOTOTROPHIC SULFUR BACTERIA THROUGH THE ANALYSIS OF IMWRNA BAND PATTERNS

Several phototrophic sulfur bacteria were identified preliminarily thr ough the analysis of the low-molecular-weight RNA fraction (lmwRNA) of bacterial cells. This fraction includes the ribosomal 5S RNA and seve ral transfer RNAs. These molecules were separated by high-resolution e lectrophoresis in polyacrylamide gels, and the resulting band patterns were used as fingerprints for the identification of the organisms. We examined a large number of well-characterized reference strains toget her with a broad range of purple sulfur bacterial isolates from freshw ater and marine environments. A cluster analysis was run using the sim ilarity matrix calculated from the band patterns. Despite the shortcom ings of the method, close relatives were clustered together yielding a number of groups consistent with the phylogenetic arrangement establi shed through the analyses of a few available 16S rRNA gene sequences. Thus, the classification obtained gives further support to rearrangeme nt of the group as the analyses of 16S rRNA gene sequences had previou sly suggested. We conclude that the analysis of lmwRNA band patterns i s a rapid and simple tool for grouping and preliminarily identifying n ew isolates of phototrophic sulfur bacteria.