FIG. 4.

Hybridization of a digoxigenin-labeled probe mixture from groundwater with the corresponding PCR products from diverse naphthalene-degrading organisms. The probe was produced by RT-PCR of groundwater mRNA. Conditions allowed ∼5% base pair mismatch. Target DNA was blotted in positions as follows: 1, unlabeled RT-PCR product from groundwater RNA; 2, negative control RT-PCR product prepared as in position 1, which lacked reverse transcriptase during cDNA synthesis; 3, salmon sperm DNA; 4, HindIII-digested bacteriophage lambda DNA; 5, no DNA; 6, P. putida G7; 7, P. putida Cg1; 8, putative Pseudomonas sp. strain Cg7; 9, C. testosteroni GZ39; 10, C. testosteroni GZ42.