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Journal of Bacteriology, February 2009, p. 747-753, Vol. 191, No. 3
0021-9193/09/$08.00+0     doi:10.1128/JB.01103-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Glycerol Metabolism Is Important for Cytotoxicity of Mycoplasma pneumoniae{triangledown}

Claudine Hames,1 Sven Halbedel,1,{dagger} Michael Hoppert,1 Joachim Frey,2 and Jörg Stülke1*

Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Grisebachstrasse 8, D-37077 Göttingen, Germany,1 Institute of Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, CH-3001 Bern, Switzerland2

Received 7 August 2008/ Accepted 15 November 2008

Glycerol is one of the few carbon sources that can be utilized by Mycoplasma pneumoniae. Glycerol metabolism involves uptake by facilitated diffusion, phosphorylation, and the oxidation of glycerol 3-phosphate to dihydroxyacetone phosphate, a glycolytic intermediate. We have analyzed the expression of the genes involved in glycerol metabolism and observed constitutive expression irrespective of the presence of glycerol or preferred carbon sources. Similarly, the enzymatic activity of glycerol kinase is not modulated by HPr-dependent phosphorylation. This lack of regulation is unique among the bacteria for which glycerol metabolism has been studied so far. Two types of enzymes catalyze the oxidation of glycerol 3-phosphate: oxidases and dehydrogenases. Here, we demonstrate that the enzyme encoded by the M. pneumoniae glpD gene is a glycerol 3-phosphate oxidase that forms hydrogen peroxide rather than NADH2. The formation of hydrogen peroxide by GlpD is crucial for cytotoxic effects of M. pneumoniae. A glpD mutant exhibited a significantly reduced formation of hydrogen peroxide and a severely reduced cytotoxicity. Attempts to isolate mutants affected in the genes of glycerol metabolism revealed that only the glpD gene, encoding the glycerol 3-phosphate oxidase, is dispensable. In contrast, the glpF and glpK genes, encoding the glycerol facilitator and the glycerol kinase, respectively, are essential in M. pneumoniae. Thus, the enzymes of glycerol metabolism are crucial for the pathogenicity of M. pneumoniae but also for other essential, yet-to-be-identified functions in the M. pneumoniae cell.

* Corresponding author. Mailing address: Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany. Phone: 49-551-393781. Fax: 49-551-393808. E-mail: jstuelk{at}gwdg.de

{triangledown} Published ahead of print on 21 November 2008.

{dagger} Present address: Institute of Cell & Molecular Biosciences, University of Newcastle, Newcastle, United Kingdom.

Journal of Bacteriology, February 2009, p. 747-753, Vol. 191, No. 3
0021-9193/09/$08.00+0     doi:10.1128/JB.01103-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Machado, C. X., Pinto, P. M., Zaha, A., Ferreira, H. B. (2009). A peroxiredoxin from Mycoplasma hyopneumoniae with a possible role in H2O2 detoxification. Microbiology 155: 3411-3419 [Abstract] [Full Text]  


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