Figure 1.

Effect of indole-3-acetic acid (IAA) on DNA topology in Ensifer meliloti cells. (A) Analysis of the relative topoisomers distribution for the plasmid pMB393. The pMB393 plasmid was purified from E. meliloti 1021 control cells and the ones treated for 30 and 60 min with IAA (0.2, 1, and 5 mM) and separated by electrophoresis in 0.7% agarose gels containing 10 μg mL⁻¹ chloroquine. (B) Topoisomers’ distribution calculated as a percentage of topoisomers with specific superhelical density versus total DNA in untreated control cells, and cells treated for 60 min with 0.2, 1, and 5 mM IAA. The topological state of each topoisomer is expressed as the specific superelical density (σ). OC, open-circular DNA; SC, supercoiled DNA. The electrophoretic mobility reported in Figure 1A is a representative image of three biological replicates.