Stress-induced outer membrane vesicle production by Pseudomonas aeruginosa.
Abstract
As an opportunistic Gram-negative pathogen, Pseudomonas aeruginosa must be able to
adapt and survive changes and stressors in its environment during the course of infection.
To aid survival in the hostile host environment, P. aeruginosa has evolved defense
mechanisms, including the production of an exopolysaccharide capsule and the secretion
of a myriad of degradative proteases and lipases. The production of outer membrane-derived
vesicles (OMVs) serves as a secretion mechanism for virulence factors as well as a
general bacterial response to envelope-acting stressors. This study investigated the
effect of sublethal physiological stressors on OMV production by P. aeruginosa and
whether the Pseudomonas quinolone signal (PQS) and the MucD periplasmic protease are
critical mechanistic factors in this response. Exposure to some environmental stressors
was determined to increase the level of OMV production as well as the activity of
AlgU, the sigma factor that controls MucD expression. Overexpression of AlgU was shown
to be sufficient to induce OMV production; however, stress-induced OMV production
was not dependent on activation of AlgU, since stress caused increased vesiculation
in strains lacking algU. We further determined that MucD levels were not an indicator
of OMV production under acute stress, and PQS was not required for OMV production
under stress or unstressed conditions. Finally, an investigation of the response of
P. aeruginosa to oxidative stress revealed that peroxide-induced OMV production requires
the presence of B-band but not A-band lipopolysaccharide. Together, these results
demonstrate that distinct mechanisms exist for stress-induced OMV production in P.
aeruginosa.
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https://hdl.handle.net/10161/10655Published Version (Please cite this version)
10.1128/JB.02267-12Publication Info
Macdonald, Ian A; & Kuehn, Meta J (2013). Stress-induced outer membrane vesicle production by Pseudomonas aeruginosa. J Bacteriol, 195(13). pp. 2971-2981. 10.1128/JB.02267-12. Retrieved from https://hdl.handle.net/10161/10655.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Margarethe Joanna Kuehn
Associate Professor of Biochemistry
Enterotoxigenic E. coli (ETEC) causes traveler's diarrhea and infant mortality in
underdeveloped countries, and Pseudomonas aeruginosa is an opportunistic pathogen
for immunocompromised patients. Like all gram negative bacteria studied to date, ETEC
and P. aeruginosa produce small outer membrane vesicles that can serve as delivery
"bombs" to host tissues. Vesicles contain a subset of outer membrane and
soluble periplasmic proteins and lipids. In tissues and sera of infected hosts,

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