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 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 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 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.

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.

Preliminary Development of a Competitive Fluorescent Quantum Dot-Based Immunochromatographic Test Strip for Sensitive Saxitoxin Detection

2020 ◽  
Vol 18 (6) ◽  
pp. 459-463
Author(s):  
John G. Bruno ◽  
Jeremy John
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Dynamic Range ◽  
Red Tide ◽  
Coupling Reaction ◽  
Test Strip ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
Band Shift ◽  
Portable Detection

Rapid and portable detection of saxitoxin (STX) and its many congeners is highly desirable to prevent paralytic shellfish poisoning due to red tide or harmful algal blooms. In this work, we describe successful preliminary efforts to develop a very sensitive general STX family test strip employing highly fluorescent red quantum dots (Qdot 655) to detect as little as 0.5 to 1 part per billion (ppb or ng/ml) of STX with a dynamic range extending to 20,000 ppb after the prototype dipstick assay was optimized. A competitive format was necessitated by the small molecule nature of STXs having only one epitope, but the decrease in Qdot fluorescence was clearly visible to the naked eye as a function of increasing STX concentration in aqueous buffer. The competitive displacement assay format required conjugation of a primary amine in STX to carboxyl-Qdot 655 via a covalent carbodiimide coupling reaction which was validated by an electrophoretic mobility band shift assay.

scholarly journals Comparative genomics reveals insights into phylogenomic taxonomy and potential algae-bacteria interactions of novel versatile Mameliella alba strain LZ-28 isolated from highly-toxic marine phycosphere

2021 ◽  
Author(s):  
Wen-zhuo Zhu ◽  
Fei-fei Xu ◽  
Yun Ye ◽  
Qiao Yang ◽  
Xiao-ling Zhang
Keyword(s):  
Comparative Genomics ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Bacterial Colonization ◽  
Amino Acid Identity ◽  
Paralytic Shellfish Poisoning ◽  
Phylogenomic Analysis ◽  
Shellfish Poisoning ◽  
Phylogenetic Affiliation ◽  
Algal Host

Phycosphere harbors cross-kingdom interactions with significant ecological relevance for harmful algal blooms (HAB) and phycotoxins biosynthesis. Previously, a new red-pigmented bacterium designated as strain LZ-28 was isolated from phycosphere microbiota of typical HAB dinoflagellate Alexandrium catenella  LZT09 which is a vitamin B 12  auxotroph and produces high levels of paralytic shellfish poisoning toxins (PST). Strain LZ-28 exhibited obvious growth-promoting activity toward its algal host, along with the production of active bioflocculanting exopolysaccharides (EPS). But the phylogenetic affiliation and genomic potential of this versatile bacterium has not yet been elucidated. In this study, we carried out combined taxonomic and phylogenomic analysis to clarify the taxonomic classification of strain LZ-28. The obtained 16S rRNA phylogeny revealed close taxonomic relationship between strain LZ-28 and other Mameliella alba members. Additional calculations of key phylogenomic parameters, average nucleotide identity (ANI), the average amino acid identity (AAI) and the digital DNA-DNA hybridization (dDDH) values based on genomes of strain LZ-28 and type strain of Mameliella alba  were all exceeded the limit of species circumscription. Collectively considering the phenotypic and biochemical characterizations, strain LZ-28 was therefore identified as a new member of Mameliella alba.  Furthermore, based on the genomic evidence, potential algae-bacteria interactions of strain LZ-28 with host algae LZT09 were elucidated through the associations with photosynthetic and antioxidant carotenoids, supplying of bacterial VB 12 to auxotroph host, and versatile EPS serving for bacterial colonization and nutrient exchange during their interactions, along with stress response systems to defense oxidative stress and quorum sensing (QS) signals benefited survival for bacteria in the symbiotic system. Comparative genomics shed light on similar genomic features between M .   alba  strains, revealed potential close associations of strain LZ-28 with its algae host, and further enriched the genomic repertoire of interactions between phycosphere microbiota and algal host LZT09.

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