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Utilization of Acyl-Homoserine Lactone Quorum Signals for Growth by a Soil Pseudomonad and Pseudomonas aeruginosa PAO1

Huang, Jean J. and Han, Jong-In and Zhang, Lian-Hui and Leadbetter, Jared R. (2003) Utilization of Acyl-Homoserine Lactone Quorum Signals for Growth by a Soil Pseudomonad and Pseudomonas aeruginosa PAO1. Applied and Environmental Microbiology, 69 (10). pp. 5941-5949. ISSN 0099-2240. http://resolver.caltech.edu/CaltechAUTHORS:HUAaem05

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Abstract

cyl-homoserine lactones (AHLs) are employed by several Proteobacteria as quorum-sensing signals. Past studies have established that these compounds are subject to biochemical decay and can be used as growth nutrients. Here we describe the isolation of a soil bacterium, Pseudomonas strain PAI-A, that degrades 3-oxododecanoyl-homoserine lactone (3OC12HSL) and other long-acyl, but not short-acyl, AHLs as sole energy sources for growth. The small-subunit rRNA gene from strain PAI-A was 98.4% identical to that of Pseudomonas aeruginosa, but the soil isolate did not produce obvious pigments or AHLs or grow under denitrifying conditions or at 42°C. The quorum-sensing bacterium P. aeruginosa, which produces both 3OC12HSL and C4HSL, was examined for the ability to utilize AHLs for growth. It did so with a specificity similar to that of strain PAI-A, i.e., degrading long-acyl but not short-acyl AHLs. In contrast to the growth observed with strain PAI-A, P. aeruginosa strain PAO1 growth on AHLs commenced only after extremely long lag phases. Liquid-chromatography-atmospheric pressure chemical ionization-mass spectrometry analyses indicate that strain PAO1 degrades long-acyl AHLs via an AHL acylase and a homoserine-generating HSL lactonase. A P. aeruginosa gene, pvdQ (PA2385), has previously been identified as being a homologue of the AHL acylase described as occurring in a Ralstonia species. Escherichia coli expressing pvdQ catalyzed the rapid inactivation of long-acyl AHLs and the release of HSL. P. aeruginosa engineered to constitutively express pvdQ did not accumulate its 3OC12HSL quorum signal when grown in rich media. However, pvdQ knockout mutants of P. aeruginosa were still able to grow by utilizing 3OC12HSL. To our knowledge, this is the first report of the degradation of AHLs by pseudomonads or other {gamma}-Proteobacteria, of AHL acylase activity in a quorum-sensing bacterium, of HSL lactonase activity in any bacterium, and of AHL degradation with specificity only towards AHLs with long side chains.


Item Type:Article
Additional Information:Copyright © 2003, American Society for Microbiology. Received 15 May 2003/ Accepted 17 July 2003 This research was supported by the National Science Foundation (DBI-0107908), the Department of Agriculture (CSREES 2001-01242), the Defense Advanced Research Projects Agency (DARPA; no. N66001-02-1-8929), the W. M. Keck Foundation Fund for Discovery in Basic Medical Research at the California Institute of Technology, and an NIH Training Grant for Biology (5T32GM07616). Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the DARPA. We thank Bob Becker and Nathan Dalleska for technical discussions and for help with performing LC/APCI-MS analyses and C. Saltikov, D. Newman, and E. R. Leadbetter for their helpful comments.
Record Number:CaltechAUTHORS:HUAaem05
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:HUAaem05
Alternative URL:http://dx.doi.org/10.1128/AEM.69.10.5941-5949.2003
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1848
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:20 Feb 2006
Last Modified:26 Dec 2012 08:46

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