Quantitation of LysRS1 protein levels by immunoblot analysis. Aliquots of total cell protein were separated by SDS/PAGE, transferred to membranes, and detected by using an anti-LysRS1 polyclonal antibody. The amounts of total cell protein loaded were as follows: B. subtilis strain 168, 20 μg; strain BCJ118.49, 20 μg; strain BCJ140.1 without xylose inducer, 20 μg; strain BCJ140.1 with xylose inducer, 1 μg; and strain BCJ157.1, 0.125 and 0.25 μg. The amount of B. burgdorferi total cell lysate loaded was 3 μg. Note that the level of LysRS1 present in this bacterium is significantly higher than that found in strain BCJ118.49 or strain BCJ140.1 (induced).