FIG. 6.

Plasmid profile of freshly prepared parent cells and the 1- and 2-year-old isolates. (a) Parent cells (lane 1), 1-year-old LCT isolates (lanes 2 and 3), 1-year-old TCT isolates (lanes 4 and 5), 1-year-old OCT isolates (lanes 6 and 7), and a plasmid standard ladder (lane 8) are shown. (b) λ-HindIII standard (lane 1), parent cells (lane 2), 2-year-old isolates (lanes 3 to 6), and a plasmid standard ladder (lane 7) are shown. The chromosomal band present in all DNA preparations is labeled “chr.”