The term “superbug” is nothing new to the microbiology world but has only been under the spotlight for a few years, which consequently led to an increasing interest in antibiotic resistance by researchers. A superbug refers to a multidrug resistant bacterium which can therefore cause untreatable and fatal infections. This particular aspect has sparked global worry that our known antibiotics will eventually fail us.
With the interest in superbugs at its highest, scientists from Indiana University and Harvard University had their share in the investigation, using multi-colored dyes called fluorescent D-amino acids (FDAAs), aka rainbow dyes, which turned out to be just as cheerful to the researchers as actual rainbows. These dyes enabled them to visualize the detailed process of cell division, particularly the movement of the filaments FtsZ and FtsA (cytoskeletal polymers and prokaryotic homologs of the protein tubulin) that determine the site of cell division by driving peptidoglycan synthesizing enzymes to the correct sites. Cytokinesis starts with the formation of a Z-ring at the site of cell division, and both FtsZ and FtsA are required for this process.
When visualized, the filaments appeared to move in circular concentric rings, in a movement which was described as “treadmilling” in which the FtsZ filament loses a molecule at one end and gains a molecule at the other end, resulting in the circular motion. With the guidance of these rings, peptidoglycan was shown to begin forming a septum dividing the cell.
A more detailed aspect of the FtsZ and FtsA system is the lack of any means to convert chemical energy into mechanical force. However, the rearrangement is primarily dependent on FtsZ polymerization dynamics under the influence of conflicting regulation by FtsA, first, by promoting FtsZ assembly and second, by inhibiting FtsZ network organization. The result of this regulation is the formation of higher ordered structures by FtsZ as tubules, circles and sheets.
These findings might be a magnificent aid in combating superbugs by visualizing so accurately their division and offering a broader comprehension of their mechanisms.
Finally, if you ever find yourself anxious about superbugs, just remember: there always comes a RAINBOW after a rainy day.