Fig. 5. Effect of growth conditions on accumulation of the A subunit of the V-ATPase. VatMpr (a,b) and DH1 (c,d) cells were grown either axenically (b,d) or for 2 days on a suspension of K. aerogenes (a,c). Cells were harvested from exponentially growing cultures, and the lysate from 1x10⁶ cells was loaded in each lane of an SDS polyacrylamide gel. After electrophoresis, the proteins were transferred to a membrane and stained with antibodies that recognize VatA and VatM (upper portion of membrane) and actin (lower portion). In bacterially grown VatMpr cells (lane a), the amount of VatA protein (normalized for actin levels) was 133% of the amount in the other samples.