Zinc and ammonium metavanadate both inhibit protein secretion from EPEC. Cultures of EPEC strain E2348/69 were grown statically overnight in DMEM with varied concentrations of zinc acetate or ammonium metavanadate to an OD600 of 0.8 - 1.0. A culture of an EPEC strain deficient in type III secretion (ΔescN) was included as a control. Cells were removed by centrifugation, then proteins in the culture medium were precipitated with 25% trichloroacetic acid and visualized with SDS-PAGE. The volume of supernatant precipitated was chosen such that volume (ml)×culture OD600 = 6.0.
Mellies et al. BMC Microbiology 2012 12:123 doi:10.1186/1471-2180-12-123