DEVELOPMENT OF A SANDWICH HYBRIDIZATION ASSAY TO RAPIDLY DETECT AND QUANTIFY HARMFUL ALGAL BLOOM (HAB) SPECIES LINKED WITH COASTAL FISH KILLS AND PUBLIC HEALTH CONCERNS

Molecular probe technologies have enabled more rapid and specific phytoplankton identification and enumeration compared to traditional technologies, such as microscopy. The method considered for this study is sandwich hybridization assay (SHA), a fast, efficient, and economic approach to detecting and quantifying plankton species. SHA employs two DNA probes, capture and signal, to detect ribosomal RNA (rRNA) sequences. The reaction entails an anti-digoxygenin horse-radish peroxidase (HRP) conjugate to which a HRP substrate is applied. The result is a colorimetric reaction, and the resultant absorbance can be used to estimate organism abundances. This project focuses on two raphidophyte HAB species that have been responsible for declining water quality and fish kills globally, but are particularly problematic in states along the southeastern (US) coast, <em>Fibrocapsa japonica </em> and <em>Chattonella subsalsa</em>. These species produce recurrent, dense blooms annually, and are directly linked with fish kills. Work presented here also includes the domoic acid (DA) producing diatom <em>Pseudo-nitzschia pseudodelicatissima</em> because DA has been associated with pigmy and dwarf sperm whale strandings in the southeastern US, and blooms of this genus are frequently reported in regional waters. Here we present findings from field samplings and multiple blooms (2014-2015) of all three species that occurred in South Carolina (US) and regional waters. We also provide updates on the development, validation, and quantification of SHA applications for each of these HAB species.