Evidence for the existence of a carD homolog in S. aurantiaca. (A) Southern analysis under low-stringency conditions of S. aurantiaca genomic DNA digested with the specific restriction enzyme indicated and with a probe corresponding to the M. xanthus carD gene. (B) Comparison of the results obtained for Southern analysis, as described for panel A, with XhoI-digested genomic DNAs from S. aurantiaca and M. xanthus. (C) Immunoblots with anti-CarD polyclonal antibodies and cell lysate samples prepared as indicated in Materials and Methods. Lane 1, purified CarD; lane 2, M. xanthus strain DK1622 (wild type); lane 3, M. xanthus strain MR1900 (ΔcarD); lane 4, S. aurantiaca strain DW4/3-1 (wild type).