Phylogenetic positions of Nocardia strains studied in the present work. The phylogenetic tree was constructed using 16S rRNA gene sequences of type strains (http://www.bacterio.cict.fr/, http://www.ncbi.nlm.nih.gov/nuccore). MEGA5 software  was used to draw non-rooted neighbor-noining phylogenic tree. Positional information of Mycobacterium tuberculosis (Genbank accession # X58890) and Streptomyces coelicolor (#AB184196) was added to the tree. Bootstrap values of 1000 re-samplings are shown only for the main branches. The five species studied in the present work were marked with red arrows.