(A) Growth of the wild type strain ATCC 13032 (black line) and the deletion mutant ATCC 13032 ΔftsH (dotted line). Doubling times of the wild type and the mutant strain were very similar (2 h 18 min versus 2 h 38 min). (B) Control of ftsH deletion by PCR. Primers were designed to anneal approx. 214 bps up and down stream of ftsH gene (2562 bps). The PCR product comprised 2990 bps in the wild type strain (lane 1) and 530 bps in the deletion mutant (lane 2), lane 3 contains marker DNA. (C) Control of ftsH deletion by Western blotting. 25 μg of membrane protein of the wild type and ΔftsH were applied per lane. No signal was obtained with cytoplasmic proteins (data not shown).