Fig 1.

Electron microscopy of P. aeruginosa after treatment with sphingosine. P. aeruginosa ATCC 27853 were treated with 20 µM sphingosine (SPH) for 10 min or 30 min or left untreated, fixed, embedded, and analyzed by electron microscopy. A higher concentration of sphingosine was used because 10⁸ CFU P. aeruginosa were used in these experiments to obtain a pellet, which we were able to process. Shown is each a representative picture from at least 50 visualized cells. The arrows in the images in the upper row indicate some of the membrane blebs, and the arrows in the image in the lower row indicate typical membrane rolls. Scale bar sizes in the images: left column (both images) and middle and right column (upper images), each 200 nm; middle column (lower image), 50 nm; right column (lower image), 100 nm.