Phycotoxins in Marine Shellfish: Origin, Occurrence and Effects on Humans

Abstract

Massive phytoplankton proliferation, and the consequent release of toxic metabolites, can be responsible for seafood poisoning outbreaks: filter-feeding mollusks, such as shellfish, mussels, oysters or clams, can accumulate these toxins throughout the food chain and present a threat for consumers’ health. Particular environmental and climatic conditions favor this natural phenomenon, called harmful algal blooms (HABs); the phytoplankton species mostly involved in these toxic events are dinoflagellates or diatoms belonging to the genera Alexandrium, Gymnodinium, Dinophysis, and Pseudo-nitzschia. Substantial economic losses ensue after HABs occurrence: the sectors mainly affected include commercial fisheries, tourism, recreational activities, and public health monitoring and management. A wide range of symptoms, from digestive to nervous, are associated to human intoxication by biotoxins, characterizing different and specific syndromes, called paralytic shellfish poisoning, amnesic shellfish poisoning, diarrhetic shellfish poisoning, and neurotoxic shellfish poisoning. This review provides a complete and updated survey of phycotoxins usually found in marine invertebrate organisms and their relevant properties, gathering information about the origin, the species where they were found, as well as their mechanism of action and main effects on humans.

First Detection of Tetrodotoxin in Bivalves and Gastropods from the French Mainland Coasts

“…[18]. TTXs may be produced by several bacterial species (e.g., Acinetobacter, Alteromonas, Bacillus, Micrococcus, Pseudomonas, Vibrio) [32,33]. On the other hand, the simultaneous presence of Prorocentrum minimum dinoflagellates and TTX in molluscs was observed in Greece [8].…”

Purification, Toxicity and Functional Characterization of a New Proteinaceous Mussel Biotoxin from Bizerte Lagoon

“…To our knowledge, this is the first time that a proteinaceous marine biotoxin, with a relatively high molecular mass (6.4 kDa), is isolated and shown to be directly involved in the contamination of mussels in shellfish farming areas. Usually, most of other contaminants have a low molecular mass and/or are non-proteinaceous compounds [31], except peptaibols that are linear peptides but with a less than 2.2 kDa of molecular mass [32][33][34]. It is worth noting that atypical toxicity episodes coincide with the detection of microfungi species such as Fusarium, Aspergillus and Trichoderma in contaminated mussels [21].…”

Scallop mantle extract inhibits insulin signaling in HepG2 cells

“…Toxification of shellfish gives large damage to seafood and fishing industries. Two types of toxicity have been detected in shellfish that was harvested in Japan: One is paralytic shellfish poisoning (PSP) and the other is diarrhetic shellfish poisoning (DSP; Farabegoli, Blanco, Rodríguez, Vieites, & Cabado, 2018;Smith & Swoboda, 2018). We reported previously that feeding the scallop mantle epithelial cell layer causes an increase in serum glucose concentration and death of rats (Hasegawa, Itagaki, Konno, & Hasegawa, 2018).…”