FIG. 3.

Southern blot hybridization showing the copy number of ISRgn1 in the genomes of different R. gnavus E1 isolates. Sizes of the fragments containing a copy of ISRgn1 are indicated (in kilobases) on the right. The DNA probed in lane 1 was from the same sample used for cloning the RumA locus shown in Fig. 1A. The relatively lower signal intensity displayed by the isolate in lane 7 was due to an incorrect quantification of the DNA concentration in the sample, whereas DNA probed in lane 6 was partially degraded. Lane 8, R. gnavus E1 Bac⁻ mutant.