Paralytic shellfish poisoning (PSP) is a potentially fatal syndrome associated with the consumption of shellfish that have accumulated toxins produced by microscopic algae. This phenomenon is the most widespread of the poisoning syndromes caused by blooms of toxic algae, commonly called "red tides" or "harmful algal blooms" (HABs).

The impacts of HABs on marine ecosystems and the seafood industry are substantial. Saxitoxins (STXs), the etiological agent of PSP, are produced by a small number of marine dinoflagellates and freshwater filamentous cyanobacteria. The biosynthetic pathway for STX synthesis is poorly understood. Synthesis of STX may involve as many as 15 - 20 genes, but none have been conclusively identified. The cyanobacteria represent an attractive model for identifying putative saxitoxin genes because of their small genomes and the wealth of genomic information available in databases. In contrast, the most significant impacts from STX toxicity derive from dinoflagellate blooms in marine systems.

We are currently pursuing a comparative genomic approach for the identification of the STX genes. This strategy involves whole genome pyrosequencing of three STX-producing strains of cyanobacteria and of normalized cDNAs from three STX-producing dinoflagellates. A variety of computational approaches are being used to identify the set of genes unique to these six strains that should contain the set of candidate STX genes. The results of this approach will provide a set of genes for future definitive biochemical and molecular verification of STX gene function, their specific roles in toxin synthesis, and their expression in nature.

FACULTY CONTACTS:

COLLABORATORS:

Dr. Donald M. Anderson, Woods Hole Oceanographic Institution
Dr. Debashish Bhattacharya, University of Iowa
Dr. Deana Erdner, University of Texas
Dr. Jeremiah Hackett, University of Arizona

More information: Red Tide Research Group