title: Colorimetric detection of Ehrlichia canis via nucleic acid hybridization in gold nano-colloids.
abstract: Canine monocytic ehrlichiosis (CME) is a major thick-bone disease of dog caused by Ehrlichia canis. Detection of this causal agent outside the laboratory using conventional methods is not effective enough. Thus an assay for E. canis detection based on the p30 outer membrane protein gene was developed. It was based on the p30 gene amplification using loop-mediated isothermal DNA amplification (LAMP). The primer set specific to six areas within the target gene were designed and tested for their sensitivity and specificity. Detection of DNA signals was based on modulation of gold nanoparticles' surface properties and performing DNA/DNA hybridization using an oligonucleotide probe. Presence of target DNA affected the gold colloid nanoparticles in terms of particle aggregation with a plasmonic color change of the gold colloids from ruby red to purple, visible by the naked eye. All the assay steps were completed within 90 min including DNA extraction without relying on standard laboratory facilities. This method was very specific to target bacteria. Its sensitivity with probe hybridization was sufficient to detect 50 copies of target DNA. This method should provide an alternative choice for point of care control and management of the disease.
authors.affiliation: Laboratory of Plant Transgenic Technology and Biosensor, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. ajimam@nu.ac.th.
authors.forename: Ajima
authors.initials: A
authors.lastname: Muangchuen
authors.affiliation: Laboratory of Plant Transgenic Technology and Biosensor, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. piyasakcha@yahoo.com.
authors.forename: Piyasak
authors.initials: P
authors.lastname: Chaumpluk
authors.affiliation: Department of Animal Husbandry, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand. annop.suriyasomboon@gmail.com.
authors.forename: Annop
authors.initials: A
authors.lastname: Suriyasomboon
authors.affiliation: Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. sanong.e@chula.ac.th.
authors.forename: Sanong
authors.initials: S
authors.lastname: Ekgasit
mesh_terms: D000818:Animals; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000235:genetics; D004283:Dog Diseases / Q000188:drug therapy; D004285:Dogs; D041061:Ehrlichia canis / Q000235:genetics*; D016873:Ehrlichiosis / Q000175:diagnosis*; D017979:Gold Colloid / Q000737:chemistry*; D008565:Membrane Proteins / Q000235:genetics; D053758:Nanoparticles; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D009693:Nucleic Acid Hybridization / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D017979:Gold Colloid; D008565:Membrane Proteins; D004247:DNA
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