scholarly journals Algal blooms of Alexandrium spp. and Paralytic Shellfish Poisoning toxicity events in mussels farmed in Sicily

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonella Costa ◽  
Vincenzina Alio ◽  
Sonia Sciortino ◽  
Luisa Nicastro ◽  
Monica Cangini ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Paralytic Shellfish Poisoning ◽  
Economic Losses ◽  
Mouse Bioassay ◽  
Shellfish Poisoning ◽  
Alexandrium Minutum ◽  
Potential Health ◽  
Paralytic Shellfish ◽  
Production Area

Marine biotoxins can accumulate in filter-feeders bivalve molluscs, that may represent a source of potential health problems being vectors of toxins, that are transferred to humans through their consumption. Harmful Algal Blooms impact on aquaculture may give also economic losses due to temporary closures of contaminated shellfish harvest and marketing. The presence of toxic algae for Paralytic Shellfish Poisoning (PSP), with recurrent toxic blooms of dinoflagellates, such as several Alexandrium species, been known since 2000 in the waters of an Ionian bay of Sicily, the Syracuse harbour, where shellfish farms are located. Our previous works reported in this area the positivity for PSP toxin in mussels (Mytilus galloprovincialis) with saxitoxin concentrations above the limit of the law and the simultaneous presence of toxic species of the genus Alexandrium in the waters. This work reports new recent episodes of algal blooms of Alexandrium minutum in the waters of the Syracuse harbour and PSP toxin contamination in farmed mussels, with values beyond the limits established by law, with the consequent immediate closure of the production area. PSP toxicity was detected with the MBA (Mouse Bioassay) with the confirm carried out with Lawrence method to quantify the total saxitoxin equivalents and characterize the toxic profile. Regular application of the implemented health plan is very important in order to prevent any risk and protect consumer health.

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.

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 Planktonic algal blooms from 2000 to 2015 in Acapulco Bay, Guerrero, Mexico

2018 ◽  
pp. 61-93 ◽  
Author(s):  
Maria Esther A. Meave del Castillo ◽  
María Eugenia Zamudio Resendiz
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Southern Oscillation ◽  
Marine Ecosystem ◽  
Cold Season ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
Cell Counts ◽  
Paralytic Shellfish ◽  
Using Data

Background and Aims: Harmful algal blooms (HABs) affect the marine ecosystem in multiple ways. The objective was to document the species that produced blooms in Acapulco Bay over a 15-year period (2000-2015) and analyze the presence of these events with El Niño-Southern Oscillation (ENSO).Methods: Thirty-five collections, made during the years 2000, 2002-2004, 2006-2011, 2013-2015, were undertaken with phytoplankton nets and Van Dorn bottle, yielding 526 samples, of which 423 were quantified using the Utermöhl method. The relationship of HAB with ENSO was made with standardized values of Multivariate ENSO Index (MEI) and the significance was evaluated with the method quadrant sums of Olmstead-Tukey.Key results: Using data of cell density and high relative abundance (>60%), 53 blooms were recorded, most of them occurring during the rainy season (June-October) and dry-cold season (November-March), plus 37 blooms reported by other authors. These 90 blooms were composed of 40 taxa: 21 diatoms and 19 dinoflagellates, the former mostly innocuous. Sixty-seven blooms had species reported as noxious, of which 11 species commonly produce toxic HAB. Toxic taxa are Pseudo-nitzschia spp. (four taxa), and seven dinoflagellates.Conclusions: Abundance analyses of Pyrodinium bahamense var. compressum and Gymnodinium catenatum against values of MEI showed a clear tendency to produce HAB in La Niña conditions. Both taxa, producers of saxitoxins, cause paralytic shellfish poisoning (PSP) and coexist in Acapulco; therefore, they present a risk to human health. Another noxious 52 taxa found in Acapulco were currently considered potential HABs, because they have been recorded at low densities. Given the sharp differences in density values of bloom-forming species found in this work compared to those reported by other authors on similar dates, it is important to perform calibration tests to rule out possible errors in cell counts.

scholarly journals New markers for qPCR detection of the dinoflagellate Alexandrium catenella in Chile

2021 ◽  
Author(s):  
Javiera Espinoza ◽  
Kyoko Yarimizu ◽  
Satoshi Nagai ◽  
Oscar Espinoza Gonzalez ◽  
Leonardo Guzman ◽  
...  
Keyword(s):  
Early Detection ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Primary Source ◽  
Paralytic Shellfish Poisoning ◽  
Distribution Range ◽  
Shellfish Poisoning ◽  
Alexandrium Catenella ◽  
Monitoring Programs ◽  
Paralytic Shellfish

Alexandrium catenella (Whedon & Kofoid) is a dinoflagellate known as a primary source of paralytic shellfish poisoning in Chile. The distribution range of harmful algal blooms generated by this species has extended during the last decades, and the frequency of these events has increased. In this work, we developed TaqMan markers from Chilean strains that can be used to identify and quantify through qPCR, which can be implemented in monitoring programs for the early detection of this species.

scholarly journals Electrophysiological Evaluation of Pacific Oyster (Crassostrea gigas) Sensitivity to Saxitoxin and Tetrodotoxin

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 380
Author(s):  
Floriane Boullot ◽  
Caroline Fabioux ◽  
Hélène Hégaret ◽  
Pierre Boudry ◽  
Philippe Soudant ◽  
...  
Keyword(s):  
Crassostrea Gigas ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Alexandrium Minutum ◽  
Paralytic Shellfish Toxins ◽  
Pacific Oysters ◽  
Paralytic Shellfish ◽  
Good Potential ◽  
First Time ◽  
Micromolar Range

Pacific oysters (Crassostrea gigas) may bio-accumulate high levels of paralytic shellfish toxins (PST) during harmful algal blooms of the genus Alexandrium. These blooms regularly occur in coastal waters, affecting oyster health and marketability. The aim of our study was to analyse the PST-sensitivity of nerves of Pacific oysters in relation with toxin bio-accumulation. The results show that C. gigas nerves have micromolar range of saxitoxin (STX) sensitivity, thus providing intermediate STX sensitivity compared to other bivalve species. However, theses nerves were much less sensitive to tetrodotoxin. The STX-sensitivity of compound nerve action potential (CNAP) recorded from oysters experimentally fed with Alexandrium minutum (toxic-alga-exposed oysters), or Tisochrysis lutea, a non-toxic microalga (control oysters), revealed that oysters could be separated into STX-resistant and STX-sensitive categories, regardless of the diet. Moreover, the percentage of toxin-sensitive nerves was lower, and the STX concentration necessary to inhibit 50% of CNAP higher, in recently toxic-alga-exposed oysters than in control bivalves. However, no obvious correlation was observed between nerve sensitivity to STX and the STX content in oyster digestive glands. None of the nerves isolated from wild and farmed oysters was detected to be sensitive to tetrodotoxin. In conclusion, this study highlights the good potential of cerebrovisceral nerves of Pacific oysters for electrophysiological and pharmacological studies. In addition, this study shows, for the first time, that C. gigas nerves have micromolar range of STX sensitivity. The STX sensitivity decreases, at least temporary, upon recent oyster exposure to dinoflagellates producing PST under natural, but not experimental environment.

scholarly journals Immunoassay Methods for Paralytic Shellfish Poisoning Toxins

2001 ◽  
Vol 84 (5) ◽  
pp. 1649-1656 ◽  
Author(s):  
Ewald Usleber ◽  
Richard Dietrich ◽  
Christine Bürk ◽  
Elisabeth Schneider ◽  
Erwin Märtlbauer
Keyword(s):  
Test Procedure ◽  
Microtiter Plate ◽  
Paralytic Shellfish Poisoning ◽  
Current Status ◽  
Mouse Bioassay ◽  
Shellfish Poisoning ◽  
Sample Extract ◽  
Paralytic Shellfish ◽  
Psp Toxins ◽  
Immunochemical Techniques

Abstract The current status of immunochemical techniques for analysis of paralytic shellfish poisoning (PSP) toxins is summarized. Important aspects regarding production of the biological reagents necessary for immunochemical methods, the characteristics of polyclonal and monoclonal antibodies against saxitoxin and neosaxitoxin, and the importance of test sensitivity and specificity are discussed. Applications of immunochemical techniques for PSP toxins include microtiter plate enzyme immunoasays and enzyme-linked immunofiltration assays for toxin detection, and immunoaffinity chromatography (IAC) for sample extract cleanup. A major advantage of enzyme immunoassay (EIA) is simplicity and rapidity of the test procedure, and higher sensitivity than other methods. However, quantitative agreement between EIA and mouse bioassay is dependent on antibody specificity and the toxin profile in the shellfish; thus, both over- and underestimation of total toxicity may occur. For screening purposes, however, EIAs offer major advantages over the mouse bioassay, which is criticized in Europe because of animal welfare. A major application of antibodies against PSP toxins is their use for extract cleanup by IAC, which gives highly purified extracts, thereby enhancing determination of PSP toxins by conventional physicochemical methods such as liquid chromatography. IAC can also be used to isolate PSP toxins for preparation of analytical standard solutions.

scholarly journals Determination of Cell Abundances and Paralytic Shellfish Toxins in Cultures of the Dinoflagellate Gymnodinium catenatum by Fourier Transform Near Infrared Spectroscopy

2018 ◽  
Vol 6 (4) ◽  
pp. 147 ◽  
Author(s):  
Marta Lopes ◽  
Ana Amorim ◽  
Cecília Calado ◽  
Pedro Reis Costa
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Near Infrared ◽  
Monitoring Program ◽  
Nir Spectroscopy ◽  
Shellfish Poisoning ◽  
Toxic Algae ◽  
Paralytic Shellfish ◽  
Gymnodinium Catenatum

Harmful algal blooms are responsible worldwide for the contamination of fishery resources, with potential impacts on seafood safety and public health. Most coastal countries rely on an intense monitoring program for the surveillance of toxic algae occurrence and shellfish contamination. The present study investigates the use of near infrared (NIR) spectroscopy for the rapid in situ determination of cell concentrations of toxic algae in seawater. The paralytic shellfish poisoning (PSP) toxin-producing dinoflagellate Gymnodinium catenatum was selected for this study. The spectral modeling by partial least squares (PLS) regression based on the recorded NIR spectra enabled the building of highly accurate (R2 = 0.92) models for cell abundance. The models also provided a good correlation between toxins measured by the conventional methods (high-performance liquid chromatography with fluorescence detection (HPLC-FLD)) and the levels predicted by the PLS/NIR models. This study represents the first necessary step in investigating the potential of application of NIR spectroscopy for algae bloom detection and alerting.

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