Neosaxitoxin ELISA Kit

Toxins produced by toxic methanogens in marine red tides can accumulate in shellfish and fish through the food chain, posing a potential threat to the aquaculture processing industry and public health. Among them, paralytic shellfish toxins (PSTs), which are highly toxic, widely distributed, and have many derivatives, are one of the most serious algal toxins that pose a threat to human beings, and can have a paralyzing effect on the human nervous system. PST attacks the nervous system by blocking sodium channels in nerve cell membranes and inhibiting the transduction of action potentials. People suffer neurotoxicity through accidental ingestion of PST-containing shellfish products, with severe cases eventually dying from respiratory muscle paralysis.

PSTs, mainly derived from freshwater cyanobacteria and marine flagellates, are a general term for a class of tetrahydropurine tricyclic toxins consisting of saxitoxin (STX) and its derivatives. Derivatives are diverse, structurally complex, and can be interconverted under certain conditions and have an impact on metabolism in living organisms. More than 28 species of PSTs have been identified, and the toxins can be classified into four groups according to the R4 group in the structure: carbamate toxins, N-sulfocarbamoyl toxins, decarbamoyl toxins, and N-hydroxycarbamoyl toxins. Among the carbamate toxins, STX is the most common PSTs and the main target of human research on PSTs at present. Depending on the chemical structure, the stability of PSTs is as follows: STX > neoSTX > GTX2,3 > GTX1,4.

Figure 1. Structure of paralytic shellfish toxins
(Source: Raposo MIC, et al. 2020)

There were large differences in the ability of different shellfish to accumulate PSTs, and the rate of shellfish toxin efflux varied markedly by species differences and season. Oysters and mussels showed faster detoxification compared to scallops, with oysters excreting 62% of PSTs within 48 h of survival in flowing seawater. Scallops have a low sensitivity to PSTs due to their low metabolic rate, which leads to a greater accumulation of toxins in their tissues, and toxic retention in scallops can persist for months after the toxic algal bloom has ceased. Decontamination methods for PSTs in shellfish include chemical, biological and physical methods. Chlorine water degradation of PSTs according to chemical regulations is a method approved by the European Commission for the decontamination of contaminated products, but there are problems such as chlorine residues or by-products. Biological methods utilize microbial metabolism or enzymatic transformation of PSTs in shellfish, but this method suffers from low efficiency and high cost. Physical decontamination, on the other hand, involves the abatement of PSTs through heating, adsorption, and temporary purification.

neoSTX ELISA Kit