Identification of bacteria by low molecular weight RNA profiles: a new chemotaxonomic approach

A new chemotaxonomic method is presented for the identification of eubacteria. This method is based on one-dimensinal gel electrophoresis of total RNA extracts from eubacteria. Only low molecular weight (<150 nucleotides) RNA, comprising 5S ribosomal and transfer RNA, was used for the identification. The high resolution of the electrophoresis, better than half a nucleotide, allowed construction of low molecular weight (LMW) RNA profiles that contained 10 to 20 bands per strain. LMW RNA profiles of a set of eubacterial reference strains showed on variation in dependence on culture conditions or physiological state of the cells. Computer-assisted data evaluation, including six molecular weight markers, enabled the calculation of relative nucleotide units (RNU) for every band. The resulting normalized band pattern allowed the identification of identical strains on different gels. The relative position of the single bands from the different groups of RNAs made an identification of bacterial strains to genus and often species level possible.Especially valuable for the identification were the large, class 2 tRNAs that showed certain variation among species of the same genus and varied considerably among different genera. RNA profiles can provide a rapid and inexpensive screening technique for the taxonomic classification of single bacterial strains. Potential fields of application for this technique might be bacterial taxonomy, biotechnology and ecology.