This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
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 arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bergholz, T. M.
Right arrow Articles by Whittam, T. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bergholz, T. M.
Right arrow Articles by Whittam, T. S.
Agricola
Right arrow Articles by Bergholz, T. M.
Right arrow Articles by Whittam, T. S.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, June 2009, p. 3542-3553, Vol. 75, No. 11
0099-2240/09/$08.00+0     doi:10.1128/AEM.02841-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Gene Expression Induced in Escherichia coli O157:H7 upon Exposure to Model Apple Juice{triangledown} ,{dagger}

Teresa M. Bergholz,* Sivapriya Kailasan Vanaja, and Thomas S. Whittam

Microbial Evolution Laboratory, National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan 48824

Received 15 December 2008/ Accepted 27 March 2009

Escherichia coli O157:H7 has caused serious outbreaks of food-borne illness via transmission in a variety of food vehicles, including unpasteurized apple juice, dried salami, and spinach. To understand how this pathogen responds to the multiple stresses of the food environment, we compared global transcription patterns before and after exposure to model apple juice. Transcriptomes of mid-exponential- and stationary-phase cells were evaluated after 10 min in model apple juice (pH 3.5) using microarrays probing 4,886 open reading frames. A total of 331 genes were significantly induced upon exposure of cells to model apple juice, including genes involved in the acid, osmotic, and oxidative stress responses as well as the envelope stress response. Acid and osmotic stress response genes, including asr, osmC, osmB, and osmY, were significantly induced in response to model apple juice. Multiple envelope stress responses were activated as evidenced by increased expression of CpxR and Rcs phosphorelay-controlled genes. Genes controlled by CpxR (cpxP, degP, and htpX) were significantly induced 2- to 15-fold upon exposure to apple juice. Inactivation of CpxRA resulted in a significant decrease in survival of O157:H7 in model apple juice compared to the isogenic parent strain. Of the 331 genes induced in model apple juice, 104 are O157-specific genes, including those encoding type three secretion effectors (espJ, espB, espM2, espL3, and espZ). Elucidating the response of O157:H7 to acidic foods provides insight into how this pathogen is able to survive in food matrices and how exposure to foods influences subsequent transmission and virulence.

* Corresponding author. Present address: 405 Stocking Hall, Department of Food Science, Cornell University, Ithaca, NY 14853. Phone: (607) 255-1266. Fax: (607) 254-4868. E-mail: tmb224{at}cornell.edu

{triangledown} Published ahead of print on 3 April 2009.

{dagger} Supplemental material for this article may be found at http://aem.asm.org/.

Applied and Environmental Microbiology, June 2009, p. 3542-3553, Vol. 75, No. 11
0099-2240/09/$08.00+0     doi:10.1128/AEM.02841-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2010 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»