Debaffling Biofilms

Courtesy of David Davies and Peg Dyrckx

Pseudomonas aeruginosa biofilm development occurs in five stages. 1. Reversible attachment: Cells transiently affix to substratum, and surface induced gene expression results in a protein profile significantly different from planktonic bacteria. 2. Irreversible attachment: Cells reorient themselves, clusters develop, motility is lost, and the las quorum sensing regulon becomes activated. 3. Maturation I: Cell clusters become thicker than 10 υm and the rhl quorum sensing system becomes active. 4. Maturation II: Cell clusters reach maximum thickness (100 υm) with a protein profile most different from planktonic cells. 5. Dispersion: Cluster structures change, and pores and channels form. Motile and non-motile bacteria are present as the protein profile begins to resemble planktonic cells once again.

In nature, bacteria exist in highly-coordinated structures known as biofilms. These densely-packed microbial communities develop when free-swimming (planktonic) cells attach to a surface and form mushroom-like structures containing stalks, ...