HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Marquart, M. E. Articles by O’Callaghan, R. J. Search for Related Content PubMed PubMed Citation Articles by Marquart, M. E. Articles by O’Callaghan, R. J.

Identification of a Novel Secreted Protease from Pseudomonas aeruginosa that Causes Corneal Erosions

¹From the Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississippi; and the ³Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin.

PURPOSE. The purpose of this study was to identify a new Pseudomonas protease and determine its possible role in keratitis.

METHODS. Concentrated culture supernatants of the Pseudomonas aeruginosa strains PA103 and ATCC 19660 were analyzed by zymography. P. aeruginosa small protease (PASP) was purified from strain PA103, and modified elastase B (LasB) was purified from strain ATCC 19660. SDS-PAGE and Western blot analysis were performed on purified PASP and modified LasB. PASP was further analyzed by mass spectrometry and amino-terminal sequencing. The Pasp gene was cloned and expressed, affinity-purified in denatured form from inclusion bodies, and refolded by removal of the denaturant. Purified recombinant PASP was analyzed by zymography for protease activity. PASP and heat-inactivated PASP were injected into rabbit corneas, and the corneas were monitored for erosions caused by protease activity.

RESULTS. Each strain produced a protease with a molecular mass of 80 kDa on zymograms. LasB antiserum identified the ATCC 19660 protease as modified LasB. Mass spectrometry defined the PA103 protease as having a molecular mass of 18.5 kDa. Amino-terminal sequencing and analysis of the P. aeruginosa genome sequence determined that the PA103 Pasp gene sequence was >99% identical with the PA0423 sequence of strain PAO1. Recombinant PASP was proteolytic, with a zymogram mass of 50 kDa. PASP purified from PA103 produced extensive corneal epithelial erosions, whereas heat-inactivated PASP produced no erosions.

CONCLUSIONS. PASP is a protease that has not been previously identified. It causes corneal epithelial erosions, indicating its likely activity as a virulence-promoting factor in Pseudomonas keratitis.

This article has been cited by other articles:

				A. Bellemare, N. Vernoux, D. Morisset, and Y. Bourbonnais Human Pre-Elafin Inhibits a Pseudomonas aeruginosa-Secreted Peptidase and Prevents Its Proliferation in Complex Media Antimicrob. Agents Chemother., February 1, 2008; 52(2): 483 - 490. [Abstract] [Full Text] [PDF]

				M. S. F. Kwong, D. J. Evans, M. Ni, B. A. Cowell, and S. M. J. Fleiszig Human Tear Fluid Protects against Pseudomonas aeruginosa Keratitis in a Murine Experimental Model Infect. Immun., May 1, 2007; 75(5): 2325 - 2332. [Abstract] [Full Text] [PDF]

				M. B. K. Bandara, H. Zhu, P. R. Sankaridurg, and M. D. P. Willcox Salicylic Acid Reduces the Production of Several Potential Virulence Factors of Pseudomonas aeruginosa Associated with Microbial Keratitis. Invest. Ophthalmol. Vis. Sci., October 1, 2006; 47(10): 4453 - 4460. [Abstract] [Full Text] [PDF]