Agarose gel electrophoresis of PCR products of actinomycetes strains by using primers NG1 and NG2. Lanes: 1 to 4, N. asteroides sensu stricto; 5 to 8, N. farcinica; 9 to 12, N. nova; 13 to 15, N. brasiliensis; 16, N. otitidiscaviarum; 17, N. carnea; 18, N. transvalensis; 19, N. brevicatena; 20, Gordona bronchialis; 21, Streptomyces spp.; 22, Rhodococcus equi; 23, Mycobacterium tuberculosis; 24, N. asteroides ATCC 19247; M, 100-bp DNA ladder (Boehringer Mannheim GmbH). pb, base pairs.