Detection of Salmonella enterica subsp. enterica via Quenching of Unincorporated Amplification Signal Reporters in Loop-Mediated Isothermal Amplification

Figure 3

Principle of quenching of unincorporated amplification signal reporters (QUASR) detection in LAMP. One of the loop primers (LF or LB) or inner primers (FIP or BIP) is labeled with a dye. The reaction mixture also contains a short probe, labeled with a dark quencher at the 3′ end and complementary to 7–13 bases at the 5′ end of the dye-labeled primer. The quench probe is present in slight excess relative to the labeled primer and has Tm > 10°C below the temperature of the LAMP reaction, such that it remains dissociated during the amplification. After incubation, the reaction is cooled to ambient temperature, resulting in the dark quenching of fluorescent primers (negative reactions) or highly fluorescent amplicons (positive reactions) [16]. Adapted from More with Less: Novel Approaches to LAMP Assay Design for Better Performance with Fewer Resources by R. Meagher, 2019.