SUPRAGENERIC CLASSIFICATION OF THERMOACTINOMYCES-VULGARIS BY NUCLEOTIDE SEQUENCING OF 5S RIBOSOMAL-RNA

The 5S rRNA nucleotide sequence of Thermoactinomyces vulgaris was dete rmined and compared with published sequences of representative Gram-po sitive bacteria. The primary and secondary structure of the sequence i s of the type characteristic of Gram-positive bacteria that have DNA w ith a low proportion of guanine plus cytosine. It was evident from the phylogenetic trees that T. vulgaris has little in common with actinom ycetes but is related to the genus Bacillus, showing a moderately high relationship with B. stearothermophilus. The taxonomic implications o f these relationships are discussed and an emended description of the family Bacillaceae is given.