title: Optimization of 6-carboxy-X-rhodamine concentration for real-time polymerase chain reaction using molecular beacon chemistry.
abstract: The optimal 6-carboxy-X-rhodamine (ROX) concentration, which is used as a passive reference dye for real-time quantitative polymerase chain reaction (PCR) with molecular beacon chemistry, was determined with the Mx4000 Multiplex Quantitative PCR System. Additionally, the effects of changing ROX concentrations on PCR reproducibility, Ct values, and efficiency were investigated with this system by using the PCR data obtained from amplification of the Escherichia coli shiga toxin 2 (stx2) gene and the Campylobacter jejuni luxS gene. This study indicated that different ROX concentrations influence many aspects of the real-time PCR reaction. ROX concentration variation could have consequences in the analysis of quantitative data and may lead to erroneous results. This study further indicated that the optimal ROX concentration is 60 nmol/L for real-time PCR, using molecular beacon chemistry for PCR assay of luxS and stx2 genes.
authors.affiliation: National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, MB R3E3R2, Canada. Gehua_Wang@PHAC-ASPC.GC.CA
authors.forename: Gehua
authors.initials: G
authors.lastname: Wang
authors.forename: Erin
authors.initials: E
authors.lastname: Becker
authors.forename: Christine
authors.initials: C
authors.lastname: Mesa
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D016123:Campylobacter jejuni / Q000235:genetics; D013437:Carbon-Sulfur Lyases / Q000235:genetics; D015342:DNA Probes; D004926:Escherichia coli / Q000235:genetics; D015335:Molecular Probes / Q000737:chemistry; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012235:Rhodamines / Q000737:chemistry; D022641:Shiga Toxin 2 / Q000235:genetics
chemical_list: C518402:6-carboxy-X-rhodamine; D001426:Bacterial Proteins; D015342:DNA Probes; D015335:Molecular Probes; D012235:Rhodamines; D022641:Shiga Toxin 2; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria