Fig. 2. (A) Effect of growth conditions on the level of VatM in VatMpr and DH1. Amoebae of DH1 (lanes a,b) and VatMpr (lanes c,d) were grown axenically (lanes a,c) or in association with K. aerogenes (lanes b,d); cells were harvested from exponentially growing cultures. Each lane of the SDS polyacrylamide gel received the lysate from 1x10⁶ cells. Following electrophoresis, the proteins were transferred to a membrane, and the upper portion of the membrane was stained with N2 antibodies, which recognize the 100 kDa V-ATPase subunit, VatM. The lower portion of the membrane was stained with anti-actin antibodies, as a control for equal loading of the lanes. (B) Immunoblot showing levels of VatM in VMop cells as a function of growth conditions. VMop-11 cells were harvested from axenic culture (lane a) or after two days of growth on a suspension of bacteria (lane b) and were immunoblotted to detect VatM and actin as described above. Similar levels of VatM were present under the two growth conditions.