SUPRAGENERIC CLASSIFICATION OF PEPTIDOGLYCAN GROUP-B ACTINOMYCETES BYNUCLEOTIDE SEQUENCING OF 5S RIBOSOMAL-RNA

5S ribosomal RNA sequences were determined for thirteen actinomycetes mainly representatives with the rare group B type peptidoglycan. The p rimary and secondary structure of the resultant sequences were of the type characteristic of Gram-positive bacteria with DNA rich in guanine plus cytosine. The sequencing and associated chemotaxonomic data prov ide compelling grounds for classifying actinomycetes with a group B ty pe peptidoglycan in a single family. The family Microbacteriaceae fam. nov. is proposed to accommodate actinomycetes classified in the gener a Agromyces, Aureobacterium, Clavibacter, Curtobacterium and Microbact erium.