Detection of two diatoms using sandwich hybridization integrated with nuclease protection assay (NPA-SH)

Nuclease protection assay (NPA) probes were designed to target the rRNA of Chaetoceros curvisetus and Skeletonema costatum, and quantitative sandwich hybridization integrated with nuclease protection assay (NPA-SH) was developed to detect C. curvisetus and S. costatum in culture and field samples in Jiaozhou Bay, China. The specificity and validity of the NPA-SH technique were tested with cultured pure strains, mixed strains and field samples, and by comparison with that of microscopy observation. The linear detection range for C. curvisetus was 4.2 × 104 to 1.2 × 106 cells with a detection limit of 42 cells ml−1. The linear range for S. costatum was 6.0 × 104 to 1.0 × 106 cells with a detection limit of 60 cells ml−1. The NPA-SH in this study provides a convenient tool for rapid assessment of HAB species in marine environments.