AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Angelidis, A. S.
Right arrow Articles by Smith, G. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Angelidis, A. S.
Right arrow Articles by Smith, G. M.
Agricola
Right arrow Articles by Angelidis, A. S.
Right arrow Articles by Smith, G. M.
Applied and Environmental Microbiology, December 2003, p. 7492-7498, Vol. 69, No. 12
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.12.7492-7498.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Role of the Glycine Betaine and Carnitine Transporters in Adaptation of Listeria monocytogenes to Chill Stress in Defined Medium

Apostolos S. Angelidis and Gary M. Smith*

Department of Food Science and Technology, University of California, Davis, California 95616

Received 8 July 2003/ Accepted 22 September 2003

The food-borne pathogen Listeria monocytogenes proliferates at refrigeration temperatures, rendering refrigeration ineffective in the preservation of Listeria-contaminated foods. The uptake and intracellular accumulation of the potent compatible solutes glycine betaine and carnitine has been shown to be a key mediator of the pathogen's cold-tolerant phenotype. To date, three compatible solute systems are known to operate in L. monocytogenes: glycine betaine porter I (BetL), glycine betaine porter II (Gbu), and the carnitine transporter OpuC. We investigated the specificity of each transporter towards each compatible solute at 4°C by examining mutant derivatives of L. monocytogenes 10403S that possess each of the transporters in isolation. Kinetic and steady-state compatible solute accumulation data together with growth rate experiments demonstrated that under cold stress glycine betaine transport is primarily mediated by Gbu and that Gbu-mediated betaine uptake results in significant growth stimulation of chill-stressed cells. BetL and OpuC can serve as minor porters for the uptake of betaine, and their action is capable of providing a small degree of cryotolerance. Under cold stress, carnitine transport occurs primarily through OpuC and results in a high level of cryoprotection. Weak carnitine transport occurs via Gbu and BetL, conferring correspondingly weak cryoprotection. No other transporter in L. monocytogenes 10403S appears to be involved in transport of either compatible solute at 4°C, since a triple mutant strain yielded neither transport nor accumulation of glycine betaine or carnitine and could not be rescued by either osmolyte when grown at that temperature.

* Corresponding author. Mailing address: Department of Food Science and Technology, University of California, Davis, CA 95616. Phone: (530) 752-6168. Fax: (530) 752-4759. E-mail: gmsmith{at}ucdavis.edu.

Applied and Environmental Microbiology, December 2003, p. 7492-7498, Vol. 69, No. 12
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.12.7492-7498.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 2003 by the American Society for Microbiology. All rights reserved.