FIG. 1.

Western blot analysis of GlnY (A) and NifH (B) synthesis of a glnBK double mutant strain (BHGLKKBS) during growth on ammonium or nitrate. Equal amounts (20 μg) of protein extracts from cells grown microaerobically on 10 mM nitrate (lane 1), aerobically on 10 mM nitrate (lane 2), microaerobically on 10 mM ammonium (preculture on nitrate) (lane 3), aerobically on 10 mM ammonium (preculture on ammonium) (lane 4), or microaerobically on 10 mM ammonium (preculture on ammonium) (lane 5) in SM medium were separated by SDS-PAGE, followed by immunodetection of GlnY and NifH.