New way of bacterial killing confirmed for the second time with another antibiotic!
My newest publication shows with high-speed atomic force microscopy how a new antibiotic attacks the membrane of bacteria. For this, I use outer membranes ("skin" of bacteria) of bacteria Staphylococcus aureus and look how the antibiotic affects them. We made our first discovery of a new way of bacterial killing a year ago: https://www.tumblr.com/miss-biophys/722540702731583488/we-found-a-new-antibiotic-target-in-bacteria?source=share. Now, we report that affecting molecular organization of the membrane might be more common than anticipated.
Healthy bacterial membrane is full of domains, thicker membrane regions vital for bacteria survival (left picture). Thanks to them, the bacterium can sense the surroundings, build a shielding layer around, sort its own biomolecules where they need to be, and more. Antibiotic N-alkylamide 3d insets itself into the membrane (middle picture) stopping and partially dissolving the domains. But affecting the domains is here only the first step of the activity. As the second step, the membrane is covered with supramolecular aggregates: balls, rods, and carpets (right picture). This could make the bacteria inaccessible to molecules from the outside and prevent waste disposal from the inside.
And now some pretty pictures from the high-speed atomic force microscope:
- Yellow is the bacterial membrane laying flat on a surface. The bright yellow spots are the thicker domains. After addition of the antibiotic, the domains stop moving and dissolve. The membrane then starts spreading over the whole underlying surface.
- The spread membrane is now everywhere. Yellow are the aggregates of the antibiotic sitting on the top of the spread membrane. We see rods, rods, twisted rods, carpets, and their mixture.
