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Environ Microbiol. 2016 Oct;18(10):3390-3402. doi: 10.1111/1462-2920.13208. Epub 2016 Feb 4.

Oxygen-dependent regulation of c-di-GMP synthesis by SadC controls alginate production in Pseudomonas aeruginosa.

Author information

1
Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany.
2
Bristol-Myers Squibb, Munich, Germany.
3
Birken AG, Niefern-Öschelbronn, Germany.
4
Clinical Research Group, 'Molecular Pathology' of Cystic Fibrosis and Pseudomonas Genomics, Hannover Medical School, 30625, Hannover, Germany.
5
Hannover and Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), German Center for Lung Research, Hannover, Germany.
6
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA, 02115, USA.
7
Ginkgo Bioworks, Boston, Massachusetts, USA.
8
Departement of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland.
9
Biochemistry Center (BZH), University of Heidelberg, 69120, Heidelberg, Germany.
10
University of Erlangen-Nürnberg, 91054, Erlangen, Germany.
11
Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, England.
12
Institute for Microbiology and Wine Research, Johannes Gutenberg University Mainz, 55099, Mainz, Germany.
13
Research Core Unit Metabolomics and Institute of Pharmacology, Hannover Medical School, 30625, Hannover, Germany.
14
Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany. sandra.schwarz@med.uni-tuebingen.de.

Abstract

Pseudomonas aeruginosa produces increased levels of alginate in response to oxygen-deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis-induced alginate production by planktonic PAO1 requires the diguanylate cyclase (DGC) SadC, previously identified as a regulator of surface-associated lifestyles. Furthermore, we found that the gene products of PA4330 and PA4331, located in a predicted operon with sadC, have a major impact on alginate production: deletion of PA4330 (odaA, for oxygen-dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA4331 (odaI, for oxygen-dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA, which did not significantly affect DGC activity of SadC, OdaI inhibited c-di-GMP production by SadC. Our data indicate that SadC, OdaA and OdaI are components of a novel response pathway of P. aeruginosa that regulates alginate synthesis in an oxygen-dependent manner.

PMID:
26743546
DOI:
10.1111/1462-2920.13208
[Indexed for MEDLINE]

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