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Journal of Bacteriology, June 2009, p. 3822-3831, Vol. 191, No. 12
0021-9193/09/$08.00+0     doi:10.1128/JB.00158-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

GerO, a Putative Na⁺/H⁺-K⁺ Antiporter, Is Essential for Normal Germination of Spores of the Pathogenic Bacterium Clostridium perfringens ^,

Daniel Paredes-Sabja,¹ Peter Setlow,³ and Mahfuzur R. Sarker^1,2*

Department of Biomedical Sciences, College of Veterinary Medicine,¹ Department of Microbiology, College of Science, Oregon State University, Corvallis, Oregon 97331,² Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030³

Received 5 February 2009/ Accepted 1 April 2009

The genome of the pathogen Clostridium perfringens encodes two proteins, GerO and GerQ, homologous to monovalent cation transporters suggested to have roles in the germination of spores of some Bacillus species. GerO and GerQ were able to transport monovalent cations (K⁺ and/or Na⁺) in Escherichia coli, and gerO and gerQ were expressed only in the mother cell compartment during C. perfringens sporulation. C. perfringens spores lacking GerO were defective in germination with a rich medium, KCl, L-asparagine, and a 1:1 chelate of Ca²⁺ and dipicolinic acid (DPA), but not with dodecylamine, and the defect was prior to DPA release in germination. All defects in gerO spores were complemented by ectopic expression of wild-type gerO. Loss of GerQ had much smaller effects on spore germination, and these effects were most evident in spores also lacking GerO. A modeled structure of GerO was similar to that of the E. coli Na⁺/H⁺ antiporter NhaA, and GerO, but not GerQ contained two adjacent Asp residues thought to be important in the function of this group of cation transporters. Replacement of these adjacent Asp residues in GerO with Asn reduced the protein's ability to complement the germination defect in gerO spores but not the ability to restore cation transport to E. coli cells defective in K⁺ uptake. Together, these data suggest that monovalent cation transporters play some role in C. perfringens spore germination. However, it is not clear whether this role is directly in germination or perhaps in spore formation.

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* Corresponding author. Mailing address: Department of Biomedical Sciences, Oregon State University, 216 Dryden Hall, Corvallis, OR 97331. Phone: (541) 737-6918. Fax: (541) 737-2730. E-mail: sarkerm{at}oregonstate.edu

Published ahead of print on 10 April 2009.

Supplemental material for this article may be found at http://jb.asm.org/.

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Journal of Bacteriology, June 2009, p. 3822-3831, Vol. 191, No. 12
0021-9193/09/$08.00+0     doi:10.1128/JB.00158-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

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• Paredes-Sabja, D., Setlow, P., Sarker, M. R. (2009). The protease CspB is essential for initiation of cortex hydrolysis and dipicolinic acid (DPA) release during germination of spores of Clostridium perfringens type A food poisoning isolates. Microbiology 155: 3464-3472 [Abstract] [Full Text]