nodularine

Nodularin is a hepatotoxic cyclic peptide cyanotoxin produced by certain cyanobacteria, most notably Nodularia spumigena. It occurs in freshwater and brackish environments where blooms of these cyanobacteria develop, particularly in coastal and brackish zones such as the Baltic Sea region. Nodularin can accumulate in water and aquatic organisms and may enter drinking-water supplies during bloom periods.

Nodularin contains an unusual Adda-like moiety essential for its biological activity and a cyclic peptide backbone. It inhibits serine/threonine protein phosphatases, primarily PP1 and PP2A, leading to hyperphosphorylation of cellular proteins, disruption of cytoskeleton, and liver cell injury.

Nodularin is a potent hepatotoxin in animals and can pose acute health risks to humans through ingestion of contaminated water or seafood and, less commonly, recreational exposure. Effects range from liver enzyme elevations to hepatic failure after substantial exposure. The toxin is relatively stable in the environment and can persist in water, making exposure during bloom periods a concern.

Monitoring relies on laboratory methods such as LC-MS/MS and ELISA, often reporting results as nodularin equivalents. Health guidelines and drinking-water standards exist in various jurisdictions, though values vary.

Prevention focuses on preventing blooms and securing water supplies during blooms; water-treatment strategies include activated carbon and advanced oxidation to remove or degrade nodularin.