FIG. 2.

DGGE gel of 16S ribosomal DNA PCR products (bases 338 to 518 [Escherichia coli rRNA sequence numbering]) from lead-contaminated and uncontaminated soil DNA extracts. The denaturant gradient in the gel ranged from 30 to 55%. Lane 1 contained markers; the PCR products were products of (from top to bottom) Pseudomonas putida, Acinetobacter sp. strain ADP1, Comamonas acidovorans ATCC 15668, E. coli DH5a, Alcaligenes sp. strain BR40, and Comamonas testosteroni). Lane 2, soil contaminated with polycyclic aromatic hydrocarbons (700 ppm); lanes 3 to 5, three I soil samples (48 mmol of Pb kg⁻¹); lanes 6 to 8, three R soil samples (3.9 mmol of Pb kg⁻¹); lanes 9 to 11, three A soil samples (3.9 μmol of Pb kg⁻¹).