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 arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Ghosh, D.
Right arrow Articles by Radosevich, M.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ghosh, D.
Right arrow Articles by Radosevich, M.
Agricola
Right arrow Articles by Ghosh, D.
Right arrow Articles by Radosevich, M.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, November 2009, p. 7142-7152, Vol. 75, No. 22
0099-2240/09/$08.00+0     doi:10.1128/AEM.00950-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Acyl-Homoserine Lactones Can Induce Virus Production in Lysogenic Bacteria: an Alternative Paradigm for Prophage Induction{triangledown}

Dhritiman Ghosh,1 Krishnakali Roy,1 Kurt E. Williamson,2 Sharath Srinivasiah,3 K. Eric Wommack,3 and Mark Radosevich1*

Biosystems Engineering & Soil Science Department, University of Tennessee, Knoxville, Tennessee 37996,1 Biology Department, College of William & Mary, Williamsburg, Virginia 23187,2 Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 197113

Received 27 April 2009/ Accepted 16 September 2009

Prophage typically are induced to a lytic cycle under stressful environmental conditions or when the host's survival is threatened. However, stress-independent, spontaneous induction also occurs in nature and may be cell density dependent, but the in vivo signal(s) that can trigger induction is unknown. In the present study, we report that acyl-homoserine lactones (AHL), the essential signaling molecules of quorum sensing in many gram-negative bacteria, can trigger phage production in soil and groundwater bacteria. This phenomenon also was operative in a {lambda} lysogen of Escherichia coli. In model coculture systems, we monitored the real-time AHL production from Pseudomonas aeruginosa PAO1 using an AHL bioluminescent sensor and demonstrated that {lambda}-prophage induction in E. coli was correlated with AHL production. As a working model in E. coli, we show that the induction responses of {lambda} with AHL remained unaffected when recA was deleted, suggesting that this mechanism does not involve an SOS response. In the same {lambda} lysogen we also demonstrated that sdiA, the AHL receptor, and rcsA, a positive transcriptional regulator of exopolysaccharide synthesis, are involved in the AHL-mediated induction process. These findings relate viral reproduction to chemical signals associated with high host cell abundance, suggesting an alternative paradigm for prophage induction.

* Corresponding author. Mailing address: Biosystems Engineering & Soil Science Department, University of Tennessee, 2506 E. J. Chapman Dr., Knoxville, TN 37996. Phone: (865) 974-7454. Fax: (865) 974-4514. E-mail: mrad{at}utk.edu

{triangledown} Published ahead of print on 25 September 2009.

Applied and Environmental Microbiology, November 2009, p. 7142-7152, Vol. 75, No. 22
0099-2240/09/$08.00+0     doi:10.1128/AEM.00950-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»