Detection of microcystin-producing Microcystis in Guanqiao Lake using a sandwich hybridization assay.

Based on sequence analyses of the mcyJ gene from Microcystis strains， a probe pair TJF and TJR was designed and a sandwich hybridization assay (SHA) was established to quantitatively detect microcystin-producing Microcystis. Through BLAST and cyanobacterial culture tests， TJF and TJR were demonstrated to be specific for microcystin-producing Microcystis. A calibration curve for the SHA was established， and the lowest detected concentration was 100 cells·mL(-1). Laboratory cultures and field samples from Guanqiao Lake were analyzed with both the SHA and microscopy. The cell number of microcystin-producing Microcystis and that of total Microcystis were compared. The biotic and abiotic components of the samples were of little disturbance to the SHA. In this study， a SHA was established to detect Microcystis， providing an alternative to PCR-ELISA and real-time PCR technology.