Immunodiffusion studies of ribosomes in classification of mycobacteria and related taxa.

Ribosomal preparations consisting of crude ribosomes (CR), 30S subunits (30S) and 16S core particles (16S) from four strains of the species Mycobacterium bovis (BCG), Mycobacterium fortuitum, Mycobacterium phlei and Mycobacterium smegmatis were analyzed by immunodiffusion technique for taxonomical purposes. The ribosomal preparations tested contained several interspecies cross-reacting precipitinogens. The number of precipitinogens demonstrated at the homologous reactions was generally larger than the number of precipitinogens shown at the heterologous reactions indicating a probable presence of species-specific antigens in ribosomes. The largest number of possible species-specific precipitinogens was demonstrated when crude ribosomal preparations were studied. However, such precipitinogens were also shown in the 30S subunits and they were individually analyzed. The 16S core particles were dominated by cross-reacting precipitinogens. The number of ribosomal precipitinogens shared by M. phlei and M. smegmatis was large indicating a close taxonomical relationship between these two species. Apart from the four mycobacterial strains studied, 15 other strains representing the genera Mycobacterium, Arthrobacterium, Corynebacterium, Kurthia, Nocardia and Rhodococcus were included in the study. The presence of intergenerically cross-reacting precipitinogens in the ribosomal preparations was demonstrated.