Title |
The Pseudomonas aeruginosa extracellular secondary metabolite, Paerucumarin, chelates iron and is not localized to extracellular membrane vesicles |
Author |
Uzma Qaisar1,2*, Cassandra J. Kruczek3, Muhammed Azeem4, Nasir Javaid2, Jane A. Colmer-Hamood1,5, and Abdul N. Hamood1,3 |
Address |
1Departments of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX79430, USA, 2School of Biological Sciences, University of the Punjab, Lahore, 54590, Pakistan, 3Surgery Department, Texas Tech University Health Sciences Center, Lubbock, TX79430, USA, 4Botany Department, Government College University, Faisalabad 38000, Pakistan, 5Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX79430, USA |
Bibliography |
Journal of Microbiology, 54(8),573-581, 2016,
|
DOI |
10.1007/s12275-016-5645-3
|
Key Words |
P. aeruginosa, paerucumarin, iron chelation, siderophore |
Abstract |
Proteins encoded by the Pseudomonas aeruginosa pvcA-D
operon synthesize a novel isonitrile functionalized cumarin
termed paerucumarin. The pvcA-D operon enhances the expression
of the P. aeruginosa fimbrial chaperone/usher pathway
(cup) genes and this effect is mediated through paerucumarin.
Whether pvcA-D and/or paerucumarin affect the
expression of other P. aeruginosa genes is not known. In this
study, we examined the effect of a mutation in pvcA-D operon
the global transcriptome of the P. aeruginosa strain PAO1-
UW. The mutation reduced the expression of several ironcontrolled
genes including pvdS, which is essential for the
expression of the pyoverdine genes. Additional transcriptional
studies showed that the pvcA-D operon is not regulated
by iron. Exogenously added paerucumarin enhanced
pyoverdine production and pvdS expression in PAO1-UW.
Iron-chelation experiments revealed that purified paerucumarin
chelates iron. However, exogenously added paerucumarin
significantly reduced the growth of a P. aeruginosa
mutant defective in pyoverdine and pyochelin production.
In contrast to other secondary metabolite, Pseudomonas quinolone
signal (PQS), paerucumarin is not localized to the
P. aeruginosa membrane vesicles. These results suggest that
paerucumarin enhances the expression of iron-controlled
genes by chelating iron within the P. aeruginosa extracellular
environment. Although paerucumarin chelates iron, it does
not function as a siderophore. Unlike PQS, paerucumarin is
not associated with the P. aeruginosa cell envelope. |