brevetoxin and yessotoxin

Microalgae, particularly those from the lineage Dinoflagellata, are very well-known for their ability to produce phycotoxins that may accumulate in the marine food chain and eventually cause poisoning in humans. This includes toxins accumulating in shellfish, such as saxitoxin, okadaic acid, yessotoxins, azaspiracids, brevetoxins, and pinnatoxins. Other toxins, such as ciguatoxins and maitotoxins, accumulate in fish, where, as is the case for the latter compounds, they can be metabolized to even more toxic metabolites. On the other hand, much less is known about the chemical nature of compounds that are toxic to fish, the so-called ichthyotoxins. Despite numerous reports of algal blooms causing massive fish kills worldwide, only a few types of compounds, such as the karlotoxins, have been proven to be true ichthyotoxins. This review will highlight marine microalgae as the source of some of the most complex natural compounds known to mankind, with chemical structures that show no resemblance to what has been characterized from plants, fungi, or bacteria. In addition, it will summarize algal species known to be related to fish-killing blooms, but from which ichthyotoxins are yet to be characterized.

Topics: Animals; Ciguatoxins; Dinoflagellida; Food Contamination; Humans; Marine Toxins; Molecular Structure; Mollusk Venoms; Oxocins; Spiro Compounds

A liquid chromatography quadrupole linear ion trap mass spectrometry method with fast polarity switching and a scheduled multiple reaction monitoring algorithm mode was developed for multiclass screening and identification of lipophilic marine biotoxins in bivalve molluscs. A major advantage of the method is that it can detect members of all six groups of lipophilic marine biotoxins [okadaic acid (OA), yessotoxins (YTX), azaspiracids (AZA), pectenotoxins (PTX), cyclic imines (CI), and brevetoxins (PbTx)], thereby allowing quantification and high confidence identification from a single liquid chromatography tandem mass spectrometry (LC-MS/MS) injection. An enhanced product ion (EPI) library was constructed after triggered collection of data via information-dependent acquisition (IDA) of EPI spectra from standard samples. A separation method for identifying 17 target toxins in a single analysis within 12min was developed and tested. Different solid phase extraction sorbents, the matrix effect (for oyster, scallop, and mussel samples), and stability of the standards also were evaluated. Matrix-matched calibration was used for quantification of the toxins. The limits of detection were 0.12-13.6μg/kg, and the limits of quantification were 0.39-45.4μg/kg. The method was used to analyze 120 shellfish samples collected from farming areas along the coast of China, and 7% of the samples were found to be contaminated with toxins. The library search identified PbTx-3, YTX, OA, PTX2, AZA1, AZA2, and desmethylspirolide C (SPX1). Overall, the method exhibited excellent sensitivity and reproducibility, and it will have broad applications in the monitoring of lipophilic marine biotoxins.

Topics: Animals; Bivalvia; Chromatography, High Pressure Liquid; Food Analysis; Gas Chromatography-Mass Spectrometry; Humans; Hydrophobic and Hydrophilic Interactions; Imines; Limit of Detection; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Ostreidae; Oxocins; Pectinidae; Pyrans; Reference Standards; Reproducibility of Results; Shellfish; Solid Phase Extraction; Spiro Compounds; Tandem Mass Spectrometry

Ladder-shaped polyether (LSP) compounds represented by brevetoxins and ciguatoxins were largely discovered in association with seafood poisoning. Thus, a quick quantification method for LSPs is potentially important. We examined a surface plasmon resonance method using desulfated-yessotoxin (dsYTX) immobilized on a sensor chip and phosphodiesterase PDEII in a inhibition detection mode. Yessotoxin, brevetoxin B and synthetic LSP derivatives showed clear inhibition against PDEII binding to the immobilized dsYTX, by which their half inhibitory concentrations were successfully estimated. This inhibition method appeared to be superior in specificity to direct binding assays where binding proteins to LSP was immobilized on a sensor chip.

Topics: Biotinylation; Ciguatoxins; Cyclic Nucleotide Phosphodiesterases, Type 2; Ethers; Marine Toxins; Mollusk Venoms; Oxocins; Surface Plasmon Resonance

Brevetoxins (BTXs) and ciguatoxins (CTXs) bind to site 5 of the voltage-gated sodium channel of excitable membranes. In the present study, we performed a competitive inhibition assay with other structurally distinct naturally occurring polyethers using isotope-labeled dihydro BTX-B ([3H]PbTx-3), which showed, for the first time, that gambierol and gambieric acid-A inhibit the binding of [3H]PbTx-3 while yessotoxins are inactive in this assay. The inhibition assay also suggested that there is a significant relationship between the size of the polycyclic region and inhibitory activity. Interestingly, the acute mouse toxicities of the compounds do not correspond directly to their inhibitory activities. These observations will serve as a guide for designing artificial polyethers with desired activity.

Topics: Animals; Binding, Competitive; Brain; Ciguatoxins; Drug Interactions; Ethers, Cyclic; Marine Toxins; Molecular Structure; Mollusk Venoms; Oxocins; Polycyclic Compounds; Protein Binding; Rats; Sodium Channels; Synaptosomes