Fig. 4

Proposed scheme for Ag nanoparticles effects on bacteria. Ag nanoparticles are suggested to affect H⁺-coupled membrane transport of bacteria. E. coli and E. hirae possessed H⁺–K⁺ exchange through F_OF₁ and K⁺-transport system (left side). In the case of E. hirae Ag nanoparticles changed the stoichiometry of H⁺–K⁺ exchange through membrane. The effect on F_OF₁ and disturbance of the interaction between F_OF₁ and K⁺-transport system (right side) might be responsible for stronger antibacterial effects with E. hirae