Xiao-Ai-Ping(XAP),a traditional oriental medicinal herb isolated from the stem of Marsdenia tenacissima(Roxb.)Wight et Arn.,has been shown to induce tumor cell apoptosis.In this study,we used confocal fluorescence microscopy and fluorescence resonance energy transfer(FRET)techniques to study the molecular mechanism of XAPinduced apoptosis in single living human lung adenocarcinoma(ASTC-a-1)cells.The efficacious apoptosis was observed at 6 h after of 100μl XAP treatment.Further monitoring the dynamics of caspase-3 activation using FRET imaging in single living ASTC-a-1 cell expressing stably with SCAT3,a FRET probe,showed that XAP activated the caspase-3 at about 2 h after XAP treatment.These data suggest that caspase-3 activation was involved in the XAP-induced apoptosis in ASTC-a-1 cells.
A new approach combined the specificity of allele-specific amplification (ASA) with the sensitivity of electrochemilu- minescence (ECL) assay for single nucleotide polymorphism (SNP) analysis was proposed. Briefly, target gene was amplified by a biotin-labeled allele-specific forward primer and a Ru(bpy)32+ (TBR)-labeled universal reverse primer. Then, the amplicon was captured onto streptavidin-coated paramagnetic beads through biotin label, and detected by measuring the ECL signal of TBR label. Different genotypes were distinguished according to the ECL values of the amplicons by different genotypic primers. K-ras oncogene was used as a target to validate the feasibility of the method. The experiment results show that the different genotypes can be clearly distinguished by ASA–ECL assay. The method is useful in SNP analysis due to its sensitivity, safety, and simplicity.
