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Di-adenosine tetraphosphate (Ap4A) metabolism impacts biofilm formation by Pseudomonas fluorescens via modulation of c-di-GMP-dependent pathways.
- Source :
-
Journal of bacteriology [J Bacteriol] 2010 Jun; Vol. 192 (12), pp. 3011-23. Date of Electronic Publication: 2010 Feb 12. - Publication Year :
- 2010
-
Abstract
- Dinucleoside tetraphosphates are common constituents of the cell and are thought to play diverse biological roles in organisms ranging from bacteria to humans. In this study we characterized two independent mechanisms by which di-adenosine tetraphosphate (Ap4A) metabolism impacts biofilm formation by Pseudomonas fluorescens. Null mutations in apaH, the gene encoding nucleoside tetraphosphate hydrolase, resulted in a marked increase in the cellular level of Ap4A. Concomitant with this increase, Pho regulon activation in low-inorganic-phosphate (P(i)) conditions was severely compromised. As a consequence, an apaH mutant was not sensitive to Pho regulon-dependent inhibition of biofilm formation. In addition, we characterized a Pho-independent role for Ap4A metabolism in regulation of biofilm formation. In P(i)-replete conditions Ap4A metabolism was found to impact expression and localization of LapA, the major adhesin regulating surface commitment by P. fluorescens. Increases in the level of c-di-GMP in the apaH mutant provided a likely explanation for increased localization of LapA to the outer membrane in response to elevated Ap4A concentrations. Increased levels of c-di-GMP in the apaH mutant were associated with increases in the level of GTP, suggesting that elevated levels of Ap4A may promote de novo purine biosynthesis. In support of this suggestion, supplementation with adenine could partially suppress the biofilm and c-di-GMP phenotypes of the apaH mutant. We hypothesize that changes in the substrate (GTP) concentration mediated by altered flux through nucleotide biosynthetic pathways may be a significant point of regulation for c-di-GMP biosynthesis and regulation of biofilm formation.
- Subjects :
- Bacterial Proteins genetics
Bacterial Proteins metabolism
Cloning, Molecular
Cyclic GMP metabolism
Gene Expression Regulation, Bacterial physiology
Mutation
Oxidative Stress
Purines metabolism
Biofilms growth & development
Cyclic GMP analogs & derivatives
Dinucleoside Phosphates metabolism
Pseudomonas fluorescens physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5530
- Volume :
- 192
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 20154123
- Full Text :
- https://doi.org/10.1128/JB.01571-09