A NOVEL METHOD FOR THE ISOLATION OF MYCOBACTERIAL DNA

DNA was isolated from mycobacteria by a simplified procedure. Cells we re suspended in 6 M guanidinium chloride, the suspension was cooled to -70 degrees C, then incubated at 65 degrees C for 10 min, cooled in i ce, deproteinized by chloroform and DNA was recovered from the superna tant. The procedure was used to obtain DNA from several mycobacteria ( 1 x 10(9) or more cells) including Mycobacterium neoaurum, M. fortuitu m, M. phlei and M. smegmatis. Each of the species was shown to have tw o ribosomal RNA operons per genome, and preliminary evidence was obtai ned which suppests that one of these operons is homologous with one of the operons of M. smegmatis.