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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Afonso, Andre S. [1, 2] ; Zanetti, Bianca F. [3] ; Santiago, Adelita C. [3] ; Henrique-Silva, Flavio [3] ; Mattoso, Luiz H. C. [2] ; Faria, Ronaldo C. [1]
Total Authors: 6
[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil
[2] Embrapa Instrumentacao Agr, BR-13560970 Sao Carlos, SP - Brazil
[3] Univ Fed Sao Carlos, Dept Genet & Evolucao, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Talanta; v. 104, p. 193-197, JAN 30 2013.
Web of Science Citations: 10

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 (Delta f) and energy dissipation (Delta D) variation in real time when 64.5 x 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. (C) 2012 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 11/02259-6 - Development of biosensors for determination of protein biomarkers to applied in early detection and monitoring of cancer
Grantee:Ronaldo Censi Faria
Support type: Scholarships abroad - Research