Biofilms: Microbial Life on Surfaces

Rodney M. Donlan


Emerging Infectious Diseases. 2002;8(9) 

In This Article

Gene Regulation by Attached Cells

Evidence is mounting that up- and down-regulation of a number of genes occurs in the attaching cells upon initial interaction with the substratum. Davies and Geesey[34] demonstrated algC up-regulation in individual bacterial cells within minutes of attachment to surfaces in a flow cell system. This phenomenon is not limited to P. aeruginosa. Prigent-Combaret et al.[35] found that 22% of these genes were up-regulated in the biofilm state, and 16% were down-regulated. Becker et al.[36] showed that biofilms of Staphylococcus aureus were up-regulated for genes encoding enzymes involved in glycolysis or fermentation (phosphoglycerate mutase, triosephosphate isomerase, and alcohol dehydrogenase) and surmised that the up-regulation of these genes could be due to oxygen limitation in the developed biofilm, favoring fermentation. A recent study by Pulcini[37] also showed that algD, algU, rpoS, and genes controlling polyphosphokinase (PPK) synthesis were up-regulated in biofilm formation of P. aeruginosa. Prigent-Combaret et al.[35] opined that the expression of genes in biofilms is evidently modulated by the dynamic physicochemical factors external to the cell and may involve complex regulatory pathways.