scholarly journals Unknown Extracellular and Bioactive Metabolites of the Genus Alexandrium: A Review of Overlooked Toxins

Toxins ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 905
Author(s):  
Marc Long ◽  
Bernd Krock ◽  
Justine Castrec ◽  
Urban Tillmann
Keyword(s):  
Detection Methods ◽  
Bioactive Metabolites ◽  
Target Cells ◽  
Paralytic Shellfish Toxins ◽  
Mammalian Cell Lines ◽  
Lack Of Information ◽  
Paralytic Shellfish ◽  
Wide Range ◽  
Ecological Importance ◽  
Experimental Strains

Various species of Alexandrium can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised bioactive extracellular compounds (BECs). The latter metabolites are released into the environment and affect a large range of organisms (from protists to fishes and mammalian cell lines). These compounds mediate allelochemical interactions, have anti-grazing and anti-parasitic activities, and have a potentially strong structuring role for the dynamic of Alexandrium blooms. In many studies evaluating the effects of Alexandrium on marine organisms, only the classical toxins were reported and the involvement of BECs was not considered. A lack of information on the presence/absence of BECs in experimental strains is likely the cause of contrasting results in the literature that render impossible a distinction between PSTs and BECs effects. We review the knowledge on Alexandrium BEC, (i.e., producing species, target cells, physiological effects, detection methods and molecular candidates). Overall, we highlight the need to identify the nature of Alexandrium BECs and urge further research on the chemical interactions according to their ecological importance in the planktonic chemical warfare and due to their potential collateral damage to a wide range of organisms.

Performance Characteristics of refined LC-FLD and HILIC-MS/MS methods for the Determination of Paralytic Shellfish Toxins in Shrimp, Whelk and Crab

2021 ◽  
Author(s):  
Karl J Dean ◽  
Robert G Hatfield ◽  
Andrew D Turner
Keyword(s):  
Performance Characteristics ◽  
Performance Criteria ◽  
Detection Methods ◽  
Official Method ◽  
Method Performance ◽  
Toxin Detection ◽  
Extraction Protocol ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Bivalve Shellfish

Abstract Background PSP toxins have been reported in non-bivalve shellfish species, including crustaceans and gastropods. Routine surveillance of these species is currently conducted in parts of England. To date detection methods have not been validated for these matrices. Validation is required to ensure the test is fit for purpose, to give greater confidence in any results generated and ultimately facilitates accreditation. Objective The aim was to test and validate two independent PSP toxin detection methods previously validated for bivalve shellfish matrices, for applicability to commercial non-bivalve species of interest. Methods Matrices were shrimp (Crangon crangon), common whelk (Buccinum undatum) and edible crab (Cancer pagurus). The two methods assessed were the pre-column oxidation LC-FLD AOAC 2005.06 Official Method of analysis and an internationally validated HILIC-MS/MS method. Brown and white crab meat were assessed separately. Results A refined extraction protocol was implemented with an increased solvent to sample ratio. The same extraction protocol was utilized for both methods, allowing both methods to be run simultaneously. Method sensitivity, recovery, repeatability, and method uncertainty were characterized in all matrix/toxin combinations. Overall, both methods performed similarly to that previously reported in bivalve molluscs. Acceptability of the majority of toxin/matrix combinations was evidenced through comparison of method performance characteristics against specific performance criteria, including Horwitz ratio values. Conclusions Both PSP toxin detection methods were found to provide acceptable performance for the monitoring of shrimp, whelk and crab species. Highlights Two PSP toxin detection methods have been single-laboratory validated successfully for three non-bivalve shellfish species.

scholarly journals A Mediterranean Alexandrium taylorii (Dinophyceae) Strain Produces Goniodomin A and Lytic Compounds but Not Paralytic Shellfish Toxins

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 564 ◽  
Author(s):  
Urban Tillmann ◽  
Bernd Krock ◽  
Stephan Wietkamp ◽  
Alfred Beran
Keyword(s):  
Evolutionary Relationship ◽  
Cell Lysis ◽  
Toxin Production ◽  
Environmental Damage ◽  
Target Cells ◽  
Fish Kills ◽  
Production Potential ◽  
Shellfish Toxins ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish

Species of the dinophyte genus Alexandrium are widely distributed and are notorious bloom formers and producers of various potent phycotoxins. The species Alexandrium taylorii is known to form recurrent and dense blooms in the Mediterranean, but its toxin production potential is poorly studied. Here we investigated toxin production potential of a Mediterranean A. taylorii clonal strain by combining state-of-the-art screening for various toxins known to be produced within Alexandrium with a sound morphological and molecular designation of the studied strain. As shown by a detailed thecal plate analysis, morphology of the A. taylorii strain AY7T from the Adriatic Sea conformed with the original species description. Moreover, newly obtained Large Subunit (LSU) and Internal Transcribed Spacers (ITS) rDNA sequences perfectly matched with the majority of other Mediterranean A. taylorii strains from the databases. Based on both ion pair chromatography coupled to post-column derivatization and fluorescence detection (LC-FLD) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis it is shown that A. taylorii AY7T does not produce paralytic shellfish toxins (PST) above a detection limit of ca. 1 fg cell−1, and also lacks any traces of spirolides and gymnodimines. The strain caused cell lysis of protistan species due to poorly characterized lytic compounds, with a density of 185 cells mL−1 causing 50% cell lysis of cryptophyte bioassay target cells (EC50). As shown here for the first time A. taylorii AY7T produced goniodomin A (GDA) at a cellular level of 11.7 pg cell−1. This first report of goniodomin (GD) production of A. taylorii supports the close evolutionary relationship of A. taylorii to other identified GD-producing Alexandrium species. As GD have been causatively linked to fish kills, future studies of Mediterranean A. taylorii blooms should include analysis of GD and should draw attention to potential links to fish kills or other environmental damage.

scholarly journals Lobster Supply Chains Are Not at Risk from Paralytic Shellfish Toxin Accumulation during Wet Storage

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 129
Author(s):  
Alison Turnbull ◽  
Andreas Seger ◽  
Jessica Jolley ◽  
Gustaaf Hallegraeff ◽  
Graeme Knowles ◽  
...  
Keyword(s):  
Negative Impact ◽  
Physiological Measures ◽  
Alexandrium Catenella ◽  
Paralytic Shellfish Toxins ◽  
Fishing Vessels ◽  
Paralytic Shellfish ◽  
Wide Range ◽  
Shellfish Toxin ◽  
Not At Risk ◽  
Toxin Accumulation

Lobster species can accumulate paralytic shellfish toxins (PST) in their hepatopancreas following the consumption of toxic prey. The Southern Rock Lobster (SRL), Jasus edwardsii, industry in Tasmania, Australia, and New Zealand, collectively valued at AUD 365 M, actively manages PST risk based on toxin monitoring of lobsters in coastal waters. The SRL supply chain predominantly provides live lobsters, which includes wet holding in fishing vessels, sea-cages, or processing facilities for periods of up to several months. Survival, quality, and safety of this largely exported high-value product is a major consideration for the industry. In a controlled experiment, SRL were exposed to highly toxic cultures of Alexandrium catenella at field relevant concentrations (2 × 105 cells L−1) in an experimental aquaculture facility over a period of 21 days. While significant PST accumulation in the lobster hepatopancreas has been reported in parallel experiments feeding lobsters with toxic mussels, no PST toxin accumulated in this experiment from exposure to toxic algal cells, and no negative impact on lobster health was observed as assessed via a wide range of behavioural, immunological, and physiological measures. We conclude that there is no risk of PST accumulation, nor risk to survival or quality at the point of consumption through exposure to toxic algal cells.

Single-Laboratory Validation of a Multitoxin Ultra-Performance LC-Hydrophilic Interaction LC-MS/MS Method for Quantitation of Paralytic Shellfish Toxins in Bivalve Shellfish

2015 ◽  
Vol 98 (3) ◽  
pp. 609-621 ◽  
Author(s):  
Andrew D Turner ◽  
Paul S McNabb ◽  
D Tim Harwood ◽  
Andrew I Selwood ◽  
Michael J Boundy
Keyword(s):  
Collaborative Study ◽  
Detection Methods ◽  
Mouse Bioassay ◽  
Hydrophilic Interaction ◽  
Method Performance ◽  
Shellfish Toxins ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Single Laboratory ◽  
Bivalve Shellfish

Abstract A single-laboratory validation study was conducted for the hydrophilic interaction-LC-MS/MS analysis of paralytic shellfish toxins (PSTs) in bivalve shellfish. The method was developed as an alternative to the precolumn oxidation AOAC 2005.06 and postcolumn oxidation AOAC 2011.02 LC with fluorescence detection methods, receptor binding assay AOAC 2011.27, as well as the mouse bioassay AOAC 959.08. PSTs assessed were saxitoxin, neosaxitoxin, deoxydecarbamoylsaxitoxin, decarbamoylsaxitoxin, decarbamoylneosaxitoxin, gonyautoxins 1-6, decarbamoylgonyautoxins 2-3, and N-sulfocarbamoyl gonyautoxins 2&3. The method also included the determination of decarbamoylgonyautoxins 1&4, N-sulfocarbamoyl gonyautoxins 1&4, and M toxins. Twelve commercially produced bivalve species from both New Zealand and the United Kingdom were assessed, including mussels, oysters, scallops, and clams. Validation studies demonstrated acceptable method performance characteristics for specificity, linearity, recovery, repeatability, and within-laboratory reproducibility. LOD and LOQ were significantly improved in comparison to current fluorescence-based detection methods, and the method was shown to be rugged. The method performed well in comparison to AOAC 2005.06, with evidence obtained from both comparative analysis of 1141 PST-contaminated samples and successful participation in proficiency testing schemes. The method is suitable for use in regulatory testing and will be submitted for an AOAC collaborative study.

Evaluation of the nucleopolyhedrovirus of Anticarsia gemmatalis as a vector for gene therapy in mammals

2020 ◽  
Vol 20 ◽  
Author(s):  
Cintia N. Parsza ◽  
Diego L. Mengual Gómez ◽  
Jorge Alejandro Simonin ◽  
Mariano Nicolás Belaich ◽  
Pablo Daniel Ghiringhelli
Keyword(s):  
Gene Therapy ◽  
Mammalian Cells ◽  
Insect Cells ◽  
Autographa Californica ◽  
Anticarsia Gemmatalis ◽  
Agricultural Pests ◽  
Mammalian Cell Lines ◽  
Delivery Vector ◽  
Wide Range ◽  
Insect Pathogens

Background: Baculoviruses are insect pathogens with important biotechnological applications that transcend their use as biological controllers of agricultural pests. One species, Autographa californica multiple nucleopolhyedrovirus (AcMNPV) has been extensively exploited as a molecular platform to produce recombinant proteins and as a delivery vector for genes in mammals, because it can transduce a wide range of mammalian cells and tissues without replicating or producing progeny. Objective/Method: To investigate if the budded virions of Anticarsia gemmatalis multiple nucleopolhyedrovirus (AgMNPV) species has the same ability, the viral genome was modified by homologous recombination into susceptible insect cells to integrate reporter genes and then it was evaluated on mammalian cell lines in comparative form with respect to equivalent viruses derived from AcMNPV. Besides, the replicative capacity of AgMNPV´s virions in mammals was determined. Results: The experiments carried out showed that the recombinant variant of AgMNPV transduces and support the expression of delivered genes but not replicates in mammalian cells. Conclusion: Consequently, this insect pathogen is proposed as an alternative of non-infectious viruses in humans to explore new approaches in gene therapy and other applications based on the use of mammalian cells.

Kaempferol Improves TRAIL-Mediated Apoptosis in Leukemia MOLT-4 Cells by the Inhibition of Anti-apoptotic Proteins and Promotion of Death Receptors Expression

2019 ◽  
Vol 19 (15) ◽  
pp. 1835-1845
Author(s):  
Ali Hassanzadeh ◽  
Adel Naimi ◽  
Majid F. Hagh ◽  
Raedeh Saraei ◽  
Faroogh Marofi ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Cancer Cells ◽  
Tumor Necrosis ◽  
Lymphoblastic Leukemia ◽  
Annexin V ◽  
Death Receptors ◽  
Target Cells ◽  
Wide Range ◽  
Apoptotic Proteins ◽  
Necrosis Factor

Introduction: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL or Apo2L) is a member of the tumor necrosis factor (TNF) superfamily, which stimulates apoptosis in a wide range of cancer cells via binding to death receptors 4 and 5 (DR4/5). Nevertheless, TRAIL has noticeable anti-cancer abilities; some cancer cells acquire resistance to TRAIL, and consequently its potential for inducing apoptosis in target cells is strongly diminished. Acute lymphoblastic leukemia MOLT-4 cell line is one of the most resistant cells to TRAIL that developed resistance to TRAIL via different pathways. We used TRAIL plus kaempferol to eliminate resistance of the MOLT-4 cells to TRAIL. Material and Methods: First, IC50 for kaempferol (95 µM) was determined by using the MTT assay. Second, the viability of the MOLT-4 cells was assayed by FACS after Annexin V/PI staining, following treatment with TRAIL (50 and 100 nM) and kaempferol (95 µM) alone and together. Finally, the expression levels of the candidate genes involved in resistance to TRAIL were assayed by real-time PCR technique. Results: Kaempferol plus TRAIL induced apoptosis robustly in MOLT-4 cells at 12, 24 and 48 hours after treatment. Additionally, we found that kaempferol could inhibit expression of the c-FLIP, X-IAP, cIAP1/2, FGF-8 and VEGF-beta, and conversely augment expression of the DR4/5 in MOLT-4 cells. Conclusion: We suggest that co-treatment of MOLT-4 cells with TRAIL plus kaempferol is a practical and attractive approach to eliminate cancers’ resistance to TRAIL via inhibition of the intracellular anti-apoptotic proteins, upregulation of DR4/5 and also by suppression of the VEGF-beta (VEGFB) and FGF-8 expressions.

scholarly journals Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ibtissame Khaoua ◽  
Guillaume Graciani ◽  
Andrey Kim ◽  
François Amblard
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Detection Methods ◽  
Strong Nonlinearity ◽  
Wide Range ◽  
Depth Analysis ◽  
Spatially Extended ◽  
Extended Sources ◽  
Photon Counting Mode

AbstractFor a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

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