Studies of nucleotide sequence homology between naphthalene-utilizing strains of bacteria

The ability of P. putida, strain NCIB 9816, to grow with naphthalene (Nah+) and salicylate (Sal+) is correlated with the presence of an 83 kilobase (kb) conjugative plasmid (pDTG1). The genes encoding the upper pathway (Nah--greater than Sal) for naphthalene degradation are located on a 15 kb EcoRI fragment which was cloned into pKT230. The resulting recombinant, pDTG113, was nick-translated and used as a radioactive probe to investigate nucleotide sequence homology between the naphthalene-utilizing organisms, P. putida G7, P. putida NP, and strain PL6. Each of these bacterial strains were isolated from different locations at different times. The results show that all of these organisms contain closely related genes that are involved in naphthalene metabolism.