Regulation of biofilm formation in Escherichia coli K12: Effect of mutations in the genes HNS, STRA, LON, and RPON

Abstract

More than 99% of bacteria exist in natural ecosystems as specifically organized biofilms adhering to solid surfaces. Biofilms have a typical architecture and are enclosed in exopolymeric matrix. Bacteria living in biofilms are extremely resistant to antibacterial factors. In this work, we studied the role of some global regulators of gene expression during biofilm formation by cells of Escherichia coli K12. The histone-like proteins H-NS and StpA were shown to play an essential role in the regulation of biofilm formation. Mutant strains deficient in H-NS or StpA generated biofilms poorly comparing with the wild-type isogenic strain. A double mutant deficient in both proteins was almost unable to the biofilm formation. Mutations in the rpoN gene, which encodes for sigma N subunit of RNA-polymerase, and the lon gene, which encodes for Lon-proteinase, increase the biofilm formation by 40–60%.