Table 2.

Comparison of cryo-ultramicrotomy preparation and traditional TEM methods for visualizing the effect of drug treatments on Xen14 cell membrane.

Treatment	Cryo-Ultramicrotomy	Traditional TEM
No treatment	clear delineation of outer and inner membrane, cell wall and peptidoglycan layer	poor delineation of membrane structure
NCL195 (2 µg/mL)	same as a control	same as a control
Colistin (0.125 µg/mL)	mesosome-like structures; swollen membranes	same as a control
Colistin (0.25 µg/mL)	mesosome-like structures; more swollen membranes	presence of tubular appendages
NCL195/colistin (2/0.25 µg/mL)	increased morphological damage; coronate tubular appendages; mesosome-like structures	increased morphological damage; coronate tubular appendages; swollen and detached membrane