Evidence that acetyl phosphate functions as a global signal during biofilm development

Abstract

SummaryWe used DNA macroarray analysis to identify genes that respond to the status of the intracellular acetyl phosphate (acP) pool. Genes whose expression correlated negatively with the ability to synthesize acP (i.e. negatively regulated genes) function primarily in flagella biosynthesis, a result consistent with observations that we published previously (Prüß and Wolfe, 1994, Mol Microbiol 12: 973-984). In contrast, genes whose expression correlated positively with the ability to synthesize acP (i.e. positively regulated genes) include those for type 1 pilus assembly, colanic acid (capsule) biosynthesis and certain stress effectors. To our knowledge, this constitutes the first report that these genes may respond to the status of the intracellular acP pool. Previously, other researchers have implicated flagella, type 1 pili, capsule and diverse stress effectors in the formation of biofilms. We therefore tested whether cells altered in their ability to metabolize acP could construct normal biofilms, and found that they could not. Cells defective for the production of acP and cells defective for the degradation of acP could both form biofilms, but these biofilms exhibited characteristics substantially different from each other and from biofilms formed by their wild-type parent. We confirmed the role of individual cell surface structures, the expression of which appears to correlate with acP levels, in fim or fli mutants that cannot assemble type 1 pili or flagella respectively. Thus, the information gained by expression profiling of cells with altered acP metabolism indicates that acP may help to co-ordinate the expression of surface structures and cellular processes involved in the initial stages of wild-type biofilm development.

Deletion analysis of RcsC reveals a novel signalling pathway controlling poly-N-acetylglucosamine synthesis and biofilm formation in Escherichia coli

“…They also showed a link between the Rcs phospho-relay and acetyl phosphate (Fredericks et al, 2006;Wolfe, 2010;Wolfe et al, 2003). Our results are in agreement with these reports and extend the knowledge of the interplay between this molecule and signal transduction mediated by RcsC.…”

Structure and evolution of the Ivy protein family, unexpected lysozyme inhibitors in Gram-negative bacteria

“…Along the same line, ivy gene products secreted by Gramnegative bacteria might also be protective for themselves and neighboring Gram-positive bacteria in natural situations, such as in biofilm (where Pseudomonas are predominant) or other symbiotic, for instance intestinal, populations (where Enterobacteria abound) (20). Finally, both Ivy and ecotin are part of the 25 genes significantly up-regulated by higher concentrations of acetyl phosphate known to promote the free living state where bacteria are more sensitive to the vertebrate innate immune system (15,20).…”

“…Finally, both Ivy and ecotin are part of the 25 genes significantly up-regulated by higher concentrations of acetyl phosphate known to promote the free living state where bacteria are more sensitive to the vertebrate innate immune system (15,20). Indeed more work is needed to identify the physiological function of Ivy genes that might lead to a reappraisal of the physiological role of C-type lysozyme and related enzymes in the control of opportunistic bacterial infections.…”

Design of artificial cell–cell communication using gene and metabolic networks

“…Uniquely qualified for this mediator role, AcP interacts with two-component regulators involved in the phosphate starvation response, nitrogen regulation, and chemotaxis, and it is an important intermediate in central metabolism (9). AcP has also been implicated as a global signal in biofilm development (10).…”