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QCM immunoassay for recombinant cysteine peptidase: a potential protein biomarker for diagnosis of citrus canker.

Authors :
Afonso AS
Zanetti BF
Santiago AC
Henrique-Silva F
Mattoso LH
Faria RC
Source :
Talanta [Talanta] 2013 Jan 30; Vol. 104, pp. 193-7. Date of Electronic Publication: 2012 Nov 13.
Publication Year :
2013

Abstract

Citrus canker is one of the most important agricultural citrus diseases worldwide. It is caused by Xanthomonas citri subsp. citri (Xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (CPXaC), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. We report here the studies on the development of piezoelectric immunoassay for CPXaC using a polyclonal antibody against CPXaC (anti-CPXaC). Three different strategies for covalent immobilization of anti-CPXaC on gold surfaces were evaluated by monitoring the frequency (Δf) and energy dissipation (ΔD) variation in real time when 64.5×10(-8) mol L(-1) CPXaC was added. Anti-CPXaC immobilized with 11-mercaptoundecanoic acid (MUA) showed the best relation between the frequency and dissipation factor variation, and strong values for the kinetic and equilibrium binding constant were obtained. The immunosensor showed a detection limit of 13.0 nmol L(-1) with excellent specificity, showing no response for different proteins that include another cysteine peptidase that is used as a target to detect Xylella fastidiosa bacterium, responsible for another important citrus disease. These results provide good perspectives for the use of CPXaC as a new biomarker for citrus canker.<br /> (Copyright © 2012 Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
1873-3573
Volume :
104
Database :
MEDLINE
Journal :
Talanta
Publication Type :
Academic Journal
Accession number :
23597909
Full Text :
https://doi.org/10.1016/j.talanta.2012.11.003