Fig. 9.

SEM and TEM micrographs of E. coli cells treated with VS2 at its MIC (5 μM) for 30 min and 60 min. (A) Untreated cells with smooth, intact surfaces. (B) Peptide-induced breakage and roughness in the cell wall after 30 min. (C) Increased damage to the bacterial cell wall in the form of cracks after 60 min. Cell shrinkage due to loss of turgor was also observed. Similarly, TEM micrographs of ultrathin sections of negatively stained, untreated E. coli cells showed a normal cell shape with an undamaged structure of inner membrane and intact outer membrane (A′). (B′) Peptide-induced breakage in the cell wall and cell membrane after 30 min. Leakage of the inner mass of the cell was also visible. (C′) Complete damage to the cell wall and inner membrane and lysis of the bacterial cell after 60 min. Arrows indicate the sites of cell membrane damage on E. coli cells.