A comparison of the physiological responses, behaviour and biotransformation of paralytic shellfish poisoning toxins in a surf-clam (Paphies donacina) and the green-lipped mussel (Perna canaliculus)

2016 ◽  
Vol 67 (8) ◽  
pp. 1163 ◽  
Author(s):  
Islay D. Marsden ◽  
Andrea M. Contreras ◽  
Lincoln MacKenzie ◽  
Murray H.G. Munro
Keyword(s):  
Algal Blooms ◽  
Physiological Responses ◽  
Paralytic Shellfish Poisoning ◽  
Alexandrium Tamarense ◽  
Shellfish Poisoning ◽  
Surf Clam ◽  
Average Value ◽  
Perna Canaliculus ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish

The accumulation of paralytic shellfish toxins (PSTs) in bivalves is species specific. We compared the physiological responses and the toxin profiles in tissues of the burrowing surf clam, Paphies donacina, and the green-lipped mussel, Perna canaliculus, exposed to the toxic dinoflagellate Alexandrium tamarense. Bivalves were supplied with the toxic algae for 10 days, then allowed a detoxification period of 8 days. Clearance rates of mussels and clams were similar when fed either with toxic A. tamarense or non-toxic A. margalefi. Byssus production in the mussel was inhibited and exhalent siphon activity in clams was erratic following exposure to A. tamarense. There were considerable differences in the toxic profile between the dinoflagellate A. tamarense, and tissues of the mussel and the surf clam, indicating that bioconversion of the PSTs had taken place. Toxin profiles of the tissues were both species and tissue specific. Following an 8-day detoxification period, total PSTs in mussels had fallen to safe concentrations below 50µg per 100g, whereas concentrations in clams remained high, with an average value greater than 600µg STX di-HCL equivalents per 100g. The results confirmed that mussels and clams are important monitoring organisms for toxic algal blooms and can be used to minimise the health risk of PSTs to humans.

scholarly journals Paralytic Shellfish Toxins (PST)-Transforming Enzymes: A Review

Toxins ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 344
Author(s):  
Mariana I. C. Raposo ◽  
Maria Teresa S. R. Gomes ◽  
Maria João Botelho ◽  
Alisa Rudnitskaya
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
Practical Applications ◽  
Drug Candidates ◽  
Shellfish Toxins ◽  
Paralytic Shellfish Toxins ◽  
Voltage Gated Sodium Channels ◽  
Paralytic Shellfish

Paralytic shellfish toxins (PSTs) are a group of toxins that cause paralytic shellfish poisoning through blockage of voltage-gated sodium channels. PSTs are produced by prokaryotic freshwater cyanobacteria and eukaryotic marine dinoflagellates. Proliferation of toxic algae species can lead to harmful algal blooms, during which seafood accumulate high levels of PSTs, posing a health threat to consumers. The existence of PST-transforming enzymes was first remarked due to the divergence of PST profiles and concentrations between contaminated bivalves and toxigenic organisms. Later, several enzymes involved in PST transformation, synthesis and elimination have been identified. The knowledge of PST-transforming enzymes is necessary for understanding the processes of toxin accumulation and depuration in mollusk bivalves. Furthermore, PST-transforming enzymes facilitate the obtainment of pure analogues of toxins as in natural sources they are present in a mixture. Pure compounds are of interest for the development of drug candidates and as analytical reference materials. PST-transforming enzymes can also be employed for the development of analytical tools for toxin detection. This review summarizes the PST-transforming enzymes identified so far in living organisms from bacteria to humans, with special emphasis on bivalves, cyanobacteria and dinoflagellates, and discusses enzymes’ biological functions and potential practical applications.

scholarly journals Saxitoxin and tetrodotoxin bioavailability increases in future oceans

2019 ◽  
Author(s):  
C.C. Roggatz ◽  
N. Fletcher ◽  
D.M. Benoit ◽  
A.C. Algar ◽  
A. Doroff ◽  
...  
Keyword(s):  
Species Interactions ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Paralytic Shellfish Poisoning ◽  
Ecosystem Stability ◽  
Shellfish Poisoning ◽  
Marine Life ◽  
Paralytic Shellfish ◽  
Water Ph ◽  
Ph Increase

Increasing atmospheric levels of carbon dioxide are largely absorbed by the world’s oceans, decreasing surface water pH1. In combination with increasing ocean temperatures, these changes have been identified as a major sustainability threat to future marine life2. Interactions between marine organisms are known to depend on biomolecules, but the influence of oceanic pH on their bioavailability and functionality remains unexplored. Here we show that global change significantly impacts two ecological keystone molecules3 in the ocean, the paralytic toxins saxitoxin (STX) and tetrodotoxin (TTX). Increasing temperatures and declining pH increase the abundance of the toxic forms of these two neurotoxins in the water. Our geospatial global model highlights where this increased toxicity could intensify the devastating impact of harmful algal blooms on ecosystems in the future, for example through an increased incidence of paralytic shellfish poisoning (PSP). We also use these results to calculate future saxitoxin toxicity levels in Alaskan clams, Saxidomus gigantea, showing critical exceedance of limits save for consumption. Our findings for TTX and STX exemplarily highlight potential consequences of changing pH and temperature on chemicals dissolved in the sea. This reveals major implications not only for ecotoxicology, but also for chemical signals mediating species interactions such as foraging, reproduction, or predation in the ocean with unexplored consequences for ecosystem stability and ecosystem services.

Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells

2001 ◽  
Vol 67 (2) ◽  
pp. 301-305 ◽  
Author(s):  
Katsushi Sekiguchi ◽  
Shigeru Sato ◽  
Shinnosuke Kaga ◽  
Takehiko Ogata ◽  
Masaaki Kodama
Keyword(s):  
Paralytic Shellfish Poisoning ◽  
Alexandrium Tamarense ◽  
Shellfish Poisoning ◽  
Paralytic Shellfish

scholarly journals A Carbamoylase-Based Bioassay for the Detection of Paralytic Shellfish Poisoning Toxins

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 507 ◽  
Author(s):  
Mariana Raposo ◽  
Maria João Botelho ◽  
Sara T. Costa ◽  
Maria Teresa S. R. Gomes ◽  
Alisa Rudnitskaya
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Chemical Sensor ◽  
Enzymatic Reaction ◽  
Enzymatic Assay ◽  
Screening Tools ◽  
Pvc Membrane ◽  
Shellfish Poisoning ◽  
Surf Clam ◽  
Paralytic Shellfish

Out of control proliferation of toxic phytoplankton, called harmful algal blooms (HABs), have a significant economic impact on bivalve aquaculture and harvesting in coastal waters. Some phytotoxins, such as paralytic shellfish toxins (PSTs), are of concern due to the life-threatening symptoms they can cause. Development of rapid and low-cost screening tools would be a welcome addition to the laboratory methodologies employed in routine monitoring programs. However, most of the assays and biosensors for the screening of PSTs, are restricted to a single target, saxitoxin (STX), which is the most potent PST. The present study aimed at developing an assay for the detection of N-sulfocarbamoyl PST—GTX5, which is one of the most abundant toxins in bivalves during G. catenatum blooms as found on the Portuguese coast. Enzymatic assay employing PSTs’ transforming enzyme—carbamoylase—was proposed. Carbamoylase was extracted and purified from the surf clam S. solida. Carbamoylase displayed similar specificity to both carbamate (STX) and N-sulfocarbamate toxins (GTX5 and C1+2) converting them into decarbamoyl saxitoxin (dcSTX) and decarbamoyl gonyautoxins 2+3 (dcGTX2+3), respectively. The enzymatic assay involved hydrolysis of GTX5 by carbamoylase and quantification of the product of enzymatic reaction, dcSTX, using a potentiometric chemical sensor. A potentiometric sensor with plasticized PVC membrane that displayed sensitivity to dcSTX and selectivity in the presence of GTX5 was employed. Enzymatic assay allowed determination of GTX5 in the concentration range from 0.43 to 3.30 µmolL−1, which encompasses levels of GTX5 in contaminated bivalve extracts with toxicities above PSTs regulatory limits. The feasibility of the carbamoylase-based potentiometric assay for detection of GTX5 was demonstrated.

scholarly journals Dose-Response Modelling of Paralytic Shellfish Poisoning (PSP) in Humans

Toxins ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 141 ◽  
Author(s):  
Nathalie Arnich ◽  
Anne Thébault
Keyword(s):  
Epidemiological Data ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
Marine Toxins ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Adverse Effect Level ◽  
Effect Level ◽  
Human Poisoning ◽  
Response Modelling

Paralytic shellfish poisoning (PSP) is caused by a group of marine toxins with saxitoxin (STX) as the reference compound. Symptoms in humans after consumption of contaminated shellfish vary from slight neurological and gastrointestinal effects to fatal respiratory paralysis. A systematic review was conducted to identify reported cases of human poisoning associated with the ingestion of shellfish contaminated with paralytic shellfish toxins (PSTs). Raw data were collected from 143 exposed individuals (113 with symptoms, 30 without symptoms) from 13 studies. Exposure estimates were based on mouse bioassays except in one study. A significant relationship between exposure to PSTs and severity of symptoms was established by ordinal modelling. The critical minimal dose with a probability higher than 10% of showing symptoms is 0.37 µg STX eq./kg b.w. This means that 10% of the individuals exposed to this dose would have symptoms (without considering the severity of the symptoms). This dose is four-fold lower than the lowest-observed-adverse-effect-level (LOAEL) established by the European Food Safety Authority (EFSA, 2009) in the region of 1.5 μg STX eq./kg b.w. This work provides critical doses that could be used as point of departure to update the acute reference dose for STX. This is the first time a dose-symptoms model could be built for marine toxins using epidemiological data.

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