Marine Toxins: Chemistry, Toxicity, Occurrence and Detection, with Special Reference to the Dutch Situation

Abstract

Various species of algae can produce marine toxins under certain circumstances. These toxins can then accumulate in shellfish such as mussels, oysters and scallops. When these contaminated shellfish species are consumed severe intoxication can occur. The different types of syndromes that can occur after consumption of contaminated shellfish, the corresponding toxins and relevant legislation are discussed in this review. Amnesic Shellfish Poisoning (ASP), Paralytic Shellfish Poisoning (PSP), Diarrheic Shellfish Poisoning (DSP) and Azaspiracid Shellfish Poisoning (AZP) occur worldwide, Neurologic Shellfish Poisoning (NSP) is mainly limited to the USA and New Zealand while the toxins causing DSP and AZP occur most frequently in Europe. The latter two toxin groups are fat-soluble and can therefore also be classified as lipophilic marine toxins. A detailed overview of the official analytical methods used in the EU (mouse or rat bioassay) and the recently developed alternative methods for the lipophilic marine toxins is given. These alternative methods are based on functional assays, biochemical assays and chemical methods. From the literature it is clear that chemical methods offer the best potential to replace the animal tests that are still legislated worldwide. Finally, an overview is given of the situation of marine toxins in The Netherlands. The rat bioassay has been used for monitoring DSP and AZP toxins in The Netherlands since the 1970s. Nowadays, a combination of a chemical method and the rat bioassay is often used. In The Netherlands toxic events are mainly caused by DSP toxins, which have been found in Dutch shellfish for the first time in 1961, and have reoccurred at irregular intervals and in varying concentrations. From this review it is clear that considerable effort is being undertaken by various research groups to phase out the animal tests that are still used for the official routine monitoring programs.

Dinoflagellates: Ecological Approaches and Spatial Distributions in Malaysia Waters

“…This heat stable toxin was isolated originally from dinoflagellate genus Karenia. The action mechanism of this toxin is totally opposite to the STX as brevetoxins stimulates the opening of sodium channel rather than blocking the inflow [54]. The potential mechanisms of action involve binding of brevetoxins at site 5 of voltage-gated sodium channel as shown in Figure 2 [55].…”

“…Onshore wind further aid the spreading of the toxin molecules 1 mile inland which was occupied with residents [59,60]. The congestion of airways with the minute toxin particles contributed to the dysfunctional of respiratory system of living things such as breathing difficulties, bronchitis and pneumonia [54,60].…”

“…Hyperphosphorylation may result from the suppression of phosphatase and eventually caused fluid loss at human cytoskeletal junctions [54]. Diarrhea and vomiting are common indications developed by the patients prior to clinical diagnosis.…”

Biological Toxins from Marine and Freshwater Microalgae

“…PSP-producing species have been found in the Adriatic Sea (Honsell et al 1992); Tyrrhenian Sea (Carrada et al 1991) and in Cape Peloro Lakes (Giacobbe and Maimone 1994), although the detection of saxitoxins has been also reported in extra-european Countries also (Gerssen et al 2010). The median lethal dose at which 50 % of the population responds (LD 50 ) for adult men is 1-2 mg, orally.…”

“…These compounds are zirael.org/index.html) has been used for drawing this structure isolated from algae of genera Dinophysis and Prorocentrum, and are responsible for DSP (Landsberg et al 2005;Lee et al 1989;Yasumoto et al 1978). At present, it has to be highlighted that OA toxins are repeatedly found in many organisms and various geographical areas with notable amounts (Gerssen et al 2010). DSP-producing algae have been found in all the world.…”