The Experts below are selected from a list of 3378 Experts worldwide ranked by ideXlab platform
Luis M Botana - One of the best experts on this subject based on the ideXlab platform.
-
new insights into the causes of human illness due to consumption of azaspiracid Contaminated Shellfish
Scientific Reports, 2015Co-Authors: Olivier P Chevallier, Katrina Campbell, Luis M Botana, Stewart F Graham, Eva Alonso, C Duffy, J Silke, Christopher T. ElliottAbstract:Azaspiracid (AZA) poisoning was unknown until 1995 when Shellfish harvested in Ireland caused illness manifesting by vomiting and diarrhoea. Further in vivo/vitro studies showed neurotoxicity linked with AZA exposure. However, the biological target of the toxin which will help explain such potent neurological activity is still unknown. A region of Irish coastline was selected and Shellfish were sampled and tested for AZA using mass spectrometry. An outbreak was identified in 2010 and samples collected before and after the contamination episode were compared for their metabolite profile using high resolution mass spectrometry. Twenty eight ions were identified at higher concentration in the Contaminated samples. Stringent bioinformatic analysis revealed putative identifications for seven compounds including, glutarylcarnitine, a glutaric acid metabolite. Glutaric acid, the parent compound linked with human neurological manifestations was subjected to toxicological investigations but was found to have no specific effect on the sodium channel (as was the case with AZA). However in combination, glutaric acid (1mM) and azaspiracid (50nM) inhibited the activity of the sodium channel by over 50%. Glutaric acid was subsequently detected in all Shellfish employed in the study. For the first time a viable mechanism for how AZA manifests itself as a toxin is presented.
-
surface plasmon resonance biosensor method for palytoxin detection based on na k atpase affinity
Toxins, 2013Co-Authors: Amparo Alfonso, Mercedes R. Vieytes, Mariajose Pazos, Andrea Fernandezaraujo, Araceli Tobio, Carmen Alfonso, Luis M BotanaAbstract:Palytoxin (PLTX), produced by dinoflagellates from the genus Ostreopsis was first discovered, isolated, and purified from zoanthids belonging to the genus Palythoa. The detection of this toxin in Contaminated Shellfish is essential for human health preservation. A broad range of studies indicate that mammalian Na+,K+-ATPase is a high affinity cellular receptor for PLTX. The toxin converts the pump into an open channel that stimulates sodium influx and potassium efflux. In this work we develop a detection method for PLTX based on its binding to the Na+,K+-ATPase. The method was developed by using the phenomenon of surface plasmon resonance (SPR) to monitor biomolecular reactions. This technique does not require any labeling of components. The interaction of PLTX over immobilized Na+,K+-ATPase is quantified by injecting different concentrations of toxin in the biosensor and checking the binding rate constant (kobs). From the representation of kobs versus PLTX concentration, the kinetic equilibrium dissociation constant (KD) for the PLTX-Na+,K+-ATPase association can be calculated. The value of this constant is KD = 6.38 × 10−7 ± 6.67 × 10−8 M PLTX. In this way the PLTX-Na+,K+-ATPase association was used as a suitable method for determination of the toxin concentration in a sample. This method represents a new and useful approach to easily detect the presence of PLTX-like compounds in marine products using the mechanism of action of these toxins and in this way reduce the use of other more expensive and animal based methods.
-
purification of five azaspiracids from mussel samples Contaminated with dsp toxins and azaspiracids
Journal of Chromatography B, 2008Co-Authors: Carmen Alfonso, Mercedes R. Vieytes, Amparo Alfonso, Paz Otero, Paula Rodriguez, Christopher T Elliot, Cowan Higgins, Luis M BotanaAbstract:Human intoxications during toxic episodes in Shellfish are a very important concern for public health, as well as for economic interests of producer regions. Although initially each toxin appeared in a determined geographical zone, nowadays many of them are found in multiple places worldwide. In addition, more toxic compounds (new toxins or new analogs of known toxins) are being isolated and identified, which bring about new risks for public health. An example of this situation is the group of azaspiracids (AZAs). Initially these toxins were concentrated in Irish coasts but today appear in many different geographic locations; in the first toxic episode only three analogs were isolated, but now it is known that the group is comprised of at least eleven identified compounds. A substantial problem associated with all these new toxins is the extreme difficulty associated with the study of their toxic effects and mechanisms of action due to the very small quantities of purified toxin available. Therefore, the study of procedures to isolate them from Contaminated Shellfish or to synthesize them is of tremendous importance. In this paper we design a complete procedure to obtain AZAs analogs from mussels Contaminated with DSP toxins and azaspiracids by means of three consecutive steps: an extraction procedure to remove toxins from Shellfish, a solid phase extraction (SPE) to clean the samples and separate DSP toxins and AZAs, and a preparative HPLC to isolate each analog. In all the steps LC/MS is used to detect and quantify the toxins. Large amounts of AZA1, AZA2, AZA3, AZA4 and AZA5 were obtained by use of this procedure, which can be utilized in future studies relating to the toxins such as the production of certified materials and standards.
-
paralytic Shellfish poisoning detection by surface plasmon resonance based biosensors in Shellfish matrixes
Analytical Chemistry, 2007Co-Authors: Eva S Fonfria, Katrina Campbell, Kentaro Kawatsu, Christopher T. Elliott, Natalia Vilariño, Simon A Haughey, Begona Bengigirey, Juan M Vieites, Luis M BotanaAbstract:The detection of paralytic Shellfish poisoning (PSP) toxins in Contaminated Shellfish is essential for human health preservation. Ethical and technical reasons have prompted the search for new detection procedures as an alternative to the mouse bioassay. On the basis of the detection of molecular interactions by surface plasmon resonance (SPR) biosensors, an inhibition assay was developed using an anti-GTX2/3 antibody (GT13-A) and a saxitoxin-CM5 chip. This assay allowed for quantification of saxitoxin (STX), decarbamoyl saxitoxin (dcSTX), gonyautoxin 2,3 (GTX2/3), decarbamoyl gonyautoxin 2,3 (dcGTX2/3), gonyautoxin 5 (GTX5), and C 1,2 (C1/2) at concentrations from 2 to 50 ng/mL. The interference of five Shellfish matrixes with the inhibition assay was analyzed. Mussels, clams, cockles, scallops, and oysters were extracted with five published methods. Ethanol extracts and acetic acid/heat extracts (AOAC Lawrence method) performed adequately in terms of surface regeneration and baseline interference, did n...
-
development of a novel immunobiosensor method for the rapid detection of okadaic acid contamination in Shellfish extracts
Analytical and Bioanalytical Chemistry, 2007Co-Authors: Nuria M Llamas, Luis M Botana, Linda D Stewart, Terry Fodey, Cowan H Higgins, Maria Luisa R Velasco, Christopher T. ElliottAbstract:The mouse bioassay is the methodology that is most widely used to detect okadaic acid (OA) in Shellfish samples. This is one of the best-known toxins, and it belongs to the family of marine biotoxins referred to as the diarrhetic Shellfish poisons (DSP). Due to animal welfare concerns, alternative methods of toxin detection are being sought. A rapid and specific biosensor immunoassay method was developed and validated for the detection of OA. An optical sensor instrument based on the surface plasmon resonance (SPR) phenomenon was utilised. A polyclonal antibody to OA was raised against OA–bovine thyroglobulin conjugate and OA–N-hydroxy succinimide ester was immobilised onto an amine sensor chip surface. The assay parameters selected for the analysis of the samples were: antibody dilution, 1/750; ratio of antibody to standard, 1:1; volume of sample injected, 25 μl min−1; flow rate, 25 μl min−1. An assay action limit of 126 ng g−1 was established by analysing of 20 Shellfish samples spiked with OA at the critical concentration of 160 ng g−1, which is the action limit established by the European Union (EU). At this concentration of OA, the assay delivered coefficient of variations (CVs) of <10%. The chip surface developed was shown to be highly stable, allowing more than 50 analyses per channel. When the concentrations of OA determined with the biosensor method were compared with the values obtained by LC–MS in Contaminated Shellfish samples, the correlation between the two analytical methods was found to be highly satisfactory (r2 = 0.991).
Christopher T. Elliott - One of the best experts on this subject based on the ideXlab platform.
-
Development and validation of a maleimide-based enzyme-linked immunosorbent assay for the detection of tetrodotoxin in oysters and mussels
Talanta, 2017Co-Authors: Laia Reverté, Katrina Campbell, Christopher T. Elliott, Arjen Gerssen, Maria Rambla-alegre, Sandra Leonardo, Carlos Bellés, Mirjam D. Klijnstra, Jorge Diogène, Mònica CampàsAbstract:The recent detection of tetrodotoxins (TTXs) in puffer fish and Shellfish in Europe highlights the necessity to monitor the levels of TTXs in seafood by rapid, specific, sensitive and reliable methods in order to protect human consumers. A previous immunoassay for TTX detection in puffer fish, based on the use of self-assembled monolayers (SAMs) for the immobilization of TTX on maleimide plates (mELISA), has been modified and adapted to the analysis of oyster and mussel samples. Changing dithiol for cysteamine-based SAMs enabled reductions in the assay time and cost, while maintaining the sensitivity of the assay. The mELISA showed high selectivity for TTX since the antibody did not cross-react with co-occurring paralytic Shellfish poisoning (PSP) toxins and no interferences were observed from arginine (Arg). Moreover, TTX-coated maleimide plates stored for 3 months at −20 °C and 4 °C were stable, thus when pre-prepared, the time to perform the assay is reduced. When analyzing Shellfish samples, matrix effects and toxin recovery values strongly depended on the Shellfish type and the sample treatment. Blank oyster extracts could be directly analyzed without solid-phase extraction (SPE) clean-up, whereas blank mussel extracts showed strong matrix effects and SPE and subsequent solvent evaporation were required for removal. However, the SPE clean-up and evaporation resulted in toxin loss. Toxin recovery values were taken as correction factors (CFs) and were applied to the quantification of TTX contents in the analysis of naturally-Contaminated Shellfish samples by mELISA. The lowest effective limits of detection (eLODs) were about 20 and 50 µg/kg for oyster extracts without and with SPE clean-up, respectively, and about 30 µg/kg for mussel extracts with both protocols, all of them substantially below the eLOD attained in the previous mELISA for puffer fish (230 µg/kg). Analysis of naturally-Contaminated samples by mELISA and comparison with LC-MS/MS quantifications demonstrated the viability of the approach. This mELISA is a selective and sensitive tool for the rapid detection of TTX in oyster and mussel samples showing promise to be implemented in routine monitoring programs to protect human health.
-
development and validation of a lateral flow immunoassay for the rapid screening of okadaic acid and all dinophysis toxins from Shellfish extracts
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Waqass Jawaid, Katrina Campbell, Julie P Meneely, Karrie Melville, Stephen J Holmes, Jennifer Rice, Christopher T. ElliottAbstract:A single-step lateral flow immunoassay was developed and validated to detect okadaic acid (OA) and dinophysis toxins (DTXs), which cause diarrhetic Shellfish poisoning. The performance characteristics of the test were investigated, in comparison to reference methods (liquid chromatography tandem mass spectrometry and/or bioassay), using both spiked and naturally Contaminated Shellfish. A portable reader was used to generate a qualitative result, indicating the absence or presence of OA-group toxins, at concentrations relevant to the maximum permitted level (MPL). Sample homogenates could be screened in 20 min (including extraction and assay time) for the presence of free toxins (OA, DTX1, DTX2). DTX3 detection could be included with the addition of a hydrolysis procedure. No matrix effects were observed from the species evaluated (mussels, scallops, oysters, and clams). Results from naturally Contaminated samples (n = 72) indicated no false compliant results and no false noncompliant results at <50% MPL. Thus, the development of a new low-cost but highly effective tool for monitoring a range of important phycotoxins has been demonstrated.
-
new insights into the causes of human illness due to consumption of azaspiracid Contaminated Shellfish
Scientific Reports, 2015Co-Authors: Olivier P Chevallier, Katrina Campbell, Luis M Botana, Stewart F Graham, Eva Alonso, C Duffy, J Silke, Christopher T. ElliottAbstract:Azaspiracid (AZA) poisoning was unknown until 1995 when Shellfish harvested in Ireland caused illness manifesting by vomiting and diarrhoea. Further in vivo/vitro studies showed neurotoxicity linked with AZA exposure. However, the biological target of the toxin which will help explain such potent neurological activity is still unknown. A region of Irish coastline was selected and Shellfish were sampled and tested for AZA using mass spectrometry. An outbreak was identified in 2010 and samples collected before and after the contamination episode were compared for their metabolite profile using high resolution mass spectrometry. Twenty eight ions were identified at higher concentration in the Contaminated samples. Stringent bioinformatic analysis revealed putative identifications for seven compounds including, glutarylcarnitine, a glutaric acid metabolite. Glutaric acid, the parent compound linked with human neurological manifestations was subjected to toxicological investigations but was found to have no specific effect on the sodium channel (as was the case with AZA). However in combination, glutaric acid (1mM) and azaspiracid (50nM) inhibited the activity of the sodium channel by over 50%. Glutaric acid was subsequently detected in all Shellfish employed in the study. For the first time a viable mechanism for how AZA manifests itself as a toxin is presented.
-
paralytic Shellfish poisoning detection by surface plasmon resonance based biosensors in Shellfish matrixes
Analytical Chemistry, 2007Co-Authors: Eva S Fonfria, Katrina Campbell, Kentaro Kawatsu, Christopher T. Elliott, Natalia Vilariño, Simon A Haughey, Begona Bengigirey, Juan M Vieites, Luis M BotanaAbstract:The detection of paralytic Shellfish poisoning (PSP) toxins in Contaminated Shellfish is essential for human health preservation. Ethical and technical reasons have prompted the search for new detection procedures as an alternative to the mouse bioassay. On the basis of the detection of molecular interactions by surface plasmon resonance (SPR) biosensors, an inhibition assay was developed using an anti-GTX2/3 antibody (GT13-A) and a saxitoxin-CM5 chip. This assay allowed for quantification of saxitoxin (STX), decarbamoyl saxitoxin (dcSTX), gonyautoxin 2,3 (GTX2/3), decarbamoyl gonyautoxin 2,3 (dcGTX2/3), gonyautoxin 5 (GTX5), and C 1,2 (C1/2) at concentrations from 2 to 50 ng/mL. The interference of five Shellfish matrixes with the inhibition assay was analyzed. Mussels, clams, cockles, scallops, and oysters were extracted with five published methods. Ethanol extracts and acetic acid/heat extracts (AOAC Lawrence method) performed adequately in terms of surface regeneration and baseline interference, did n...
-
development of a novel immunobiosensor method for the rapid detection of okadaic acid contamination in Shellfish extracts
Analytical and Bioanalytical Chemistry, 2007Co-Authors: Nuria M Llamas, Luis M Botana, Linda D Stewart, Terry Fodey, Cowan H Higgins, Maria Luisa R Velasco, Christopher T. ElliottAbstract:The mouse bioassay is the methodology that is most widely used to detect okadaic acid (OA) in Shellfish samples. This is one of the best-known toxins, and it belongs to the family of marine biotoxins referred to as the diarrhetic Shellfish poisons (DSP). Due to animal welfare concerns, alternative methods of toxin detection are being sought. A rapid and specific biosensor immunoassay method was developed and validated for the detection of OA. An optical sensor instrument based on the surface plasmon resonance (SPR) phenomenon was utilised. A polyclonal antibody to OA was raised against OA–bovine thyroglobulin conjugate and OA–N-hydroxy succinimide ester was immobilised onto an amine sensor chip surface. The assay parameters selected for the analysis of the samples were: antibody dilution, 1/750; ratio of antibody to standard, 1:1; volume of sample injected, 25 μl min−1; flow rate, 25 μl min−1. An assay action limit of 126 ng g−1 was established by analysing of 20 Shellfish samples spiked with OA at the critical concentration of 160 ng g−1, which is the action limit established by the European Union (EU). At this concentration of OA, the assay delivered coefficient of variations (CVs) of <10%. The chip surface developed was shown to be highly stable, allowing more than 50 analyses per channel. When the concentrations of OA determined with the biosensor method were compared with the values obtained by LC–MS in Contaminated Shellfish samples, the correlation between the two analytical methods was found to be highly satisfactory (r2 = 0.991).
Thomas M Burbacher - One of the best experts on this subject based on the ideXlab platform.
-
public health risks associated with chronic low level domoic acid exposure a review of the evidence
Pharmacology & Therapeutics, 2021Co-Authors: Rebekah Petroff, Kimberly S Grant, Sara Shum, Kathi A Lefebvre, Alicia Hendrix, Thomas M BurbacherAbstract:Domoic acid (DA), the causative agent for the human syndrome Amnesic Shellfish Poisoning (ASP), is a potent, naturally occurring neurotoxin produced by common marine algae. DA accumulates in seafood, and humans and wildlife alike can subsequently be exposed when consuming DA-Contaminated Shellfish or finfish. While strong regulatory limits protect people from the acute effects associated with ASP, DA is an increasingly significant public health concern, particularly for coastal dwelling populations, and there is a growing body of evidence suggesting that there are significant health consequences following repeated exposures to levels of the toxin below current safety guidelines. However, gaps in scientific knowledge make it difficult to precisely determine the risks of contemporary low-level exposure scenarios. The present review characterizes the toxicokinetics and neurotoxicology of DA, discussing results from clinical and preclinical studies after both adult and developmental DA exposure. The review also highlights crucial areas for future DA research and makes the case that DA safety limits need to be reassessed to best protect public health from deleterious effects of this widespread marine toxin.
-
preclinical modeling of exposure to a global marine bio contaminant effects of in utero domoic acid exposure on neonatal behavior and infant memory
Neurotoxicology and Teratology, 2019Co-Authors: Kimberly S Grant, Brenda Crouthamel, Caroline Kenney, Noelle Mckain, Rebekah Petroff, Sara Shum, Jing Jing, Nina Isoherranen, Thomas M BurbacherAbstract:Abstract Domoic Acid (DA) is a naturally-occurring marine neurotoxin that is increasingly recognized as an important public health issue. Prenatal DA exposure occurs through the maternal consumption of Contaminated Shellfish/finfish. To better understand the fetal risks associated with DA, we initiated a longitudinal, preclinical study focused on the reproductive and developmental effects of chronic, low-dose oral DA exposure. To this end, 32 adult female Macaca fascicularis monkeys were orally dosed with 0, 0.075 or 0.15 mg/kg/day DA on a daily basis prior to breeding and throughout breeding and pregnancy. The doses included the proposed human Tolerable Daily Intake (TDI) (0.075 mg/kg/day) for DA. Adult females were bred to nonexposed males. To evaluate development during early infancy, offspring were administered a Neonatal Assessment modeled after the human Neonatal Behavior Assessment Scale and a series of Visual Recognition Memory problems using the novelty paradigm. Results indicated that prenatal DA exposure did not impact early survival reflexes or responsivity to the environment. Findings from the recognition memory assessment, given between 1 and 2 months of age, showed that exposed and control infants demonstrated robust novelty scores when test problems were relatively easy to solve. Performance was not diminished by the introduction of delay periods. However, when more difficult recognition problems were introduced, the looking behavior of the 0.15 mg/kg DA group was random and infants failed to show differential visual attention to novel test stimuli. This finding suggests subtle but significant impairment in recognition memory and demonstrates that chronic fetal exposure to DA may impact developing cognitive processes.
-
preclinical modeling of exposure to a global marine bio contaminant effects of in utero domoic acid exposure on neonatal behavior and infant memory
bioRxiv, 2018Co-Authors: Kimberly S Grant, Brenda Crouthamel, Caroline Kenney, Noelle Mckain, Rebekah Petroff, Sara Shum, Jing Jing, Nina Isoherranen, Thomas M BurbacherAbstract:Domoic Acid (DA) is a naturally-occurring marine neurotoxin that is increasingly recognized as an important public health issue. Prenatal DA exposure occurs through the maternal consumption of Contaminated Shellfish/finfish. To better understand the fetal risks associated with DA, we initiated a longitudinal, preclinical study focused on the reproductive and developmental effects of chronic, low-dose oral DA exposure. To this end, 32 adult female Macaca fascicularis monkeys were orally dosed with 0, 0.075 or 0.15 mg/kg/day DA on a daily basis throughout breeding and pregnancy. The doses included the proposed human Tolerable Daily Intake (TDI) (0.075 mg/kg/day) for DA. Adult females were bred to nonexposed males. To evaluate behavioral development during early infancy, offspring were administered a neonatal exam modeled after the human Neonatal Behavior Assessment Scale and a series of visual recognition memory problems. Results indicated that DA does not impact early survival reflexes or responsivity to the environment during the neonatal period. Findings from recognition memory tests showed that exposed and control infants demonstrated robust novelty scores when test problems were relatively easy to solve. However, infants in the 0.15 mg/kg DA group failed to demonstrate a novelty response when problems became more challenging. This study is the first to evaluate the offspring neurodevelopmental effects of prenatal DA exposure in a translational primate model and results indicate subtle but significant consequences on emerging memory processes.
Katrina Campbell - One of the best experts on this subject based on the ideXlab platform.
-
Development and validation of a maleimide-based enzyme-linked immunosorbent assay for the detection of tetrodotoxin in oysters and mussels
Talanta, 2017Co-Authors: Laia Reverté, Katrina Campbell, Christopher T. Elliott, Arjen Gerssen, Maria Rambla-alegre, Sandra Leonardo, Carlos Bellés, Mirjam D. Klijnstra, Jorge Diogène, Mònica CampàsAbstract:The recent detection of tetrodotoxins (TTXs) in puffer fish and Shellfish in Europe highlights the necessity to monitor the levels of TTXs in seafood by rapid, specific, sensitive and reliable methods in order to protect human consumers. A previous immunoassay for TTX detection in puffer fish, based on the use of self-assembled monolayers (SAMs) for the immobilization of TTX on maleimide plates (mELISA), has been modified and adapted to the analysis of oyster and mussel samples. Changing dithiol for cysteamine-based SAMs enabled reductions in the assay time and cost, while maintaining the sensitivity of the assay. The mELISA showed high selectivity for TTX since the antibody did not cross-react with co-occurring paralytic Shellfish poisoning (PSP) toxins and no interferences were observed from arginine (Arg). Moreover, TTX-coated maleimide plates stored for 3 months at −20 °C and 4 °C were stable, thus when pre-prepared, the time to perform the assay is reduced. When analyzing Shellfish samples, matrix effects and toxin recovery values strongly depended on the Shellfish type and the sample treatment. Blank oyster extracts could be directly analyzed without solid-phase extraction (SPE) clean-up, whereas blank mussel extracts showed strong matrix effects and SPE and subsequent solvent evaporation were required for removal. However, the SPE clean-up and evaporation resulted in toxin loss. Toxin recovery values were taken as correction factors (CFs) and were applied to the quantification of TTX contents in the analysis of naturally-Contaminated Shellfish samples by mELISA. The lowest effective limits of detection (eLODs) were about 20 and 50 µg/kg for oyster extracts without and with SPE clean-up, respectively, and about 30 µg/kg for mussel extracts with both protocols, all of them substantially below the eLOD attained in the previous mELISA for puffer fish (230 µg/kg). Analysis of naturally-Contaminated samples by mELISA and comparison with LC-MS/MS quantifications demonstrated the viability of the approach. This mELISA is a selective and sensitive tool for the rapid detection of TTX in oyster and mussel samples showing promise to be implemented in routine monitoring programs to protect human health.
-
development and validation of a lateral flow immunoassay for the rapid screening of okadaic acid and all dinophysis toxins from Shellfish extracts
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Waqass Jawaid, Katrina Campbell, Julie P Meneely, Karrie Melville, Stephen J Holmes, Jennifer Rice, Christopher T. ElliottAbstract:A single-step lateral flow immunoassay was developed and validated to detect okadaic acid (OA) and dinophysis toxins (DTXs), which cause diarrhetic Shellfish poisoning. The performance characteristics of the test were investigated, in comparison to reference methods (liquid chromatography tandem mass spectrometry and/or bioassay), using both spiked and naturally Contaminated Shellfish. A portable reader was used to generate a qualitative result, indicating the absence or presence of OA-group toxins, at concentrations relevant to the maximum permitted level (MPL). Sample homogenates could be screened in 20 min (including extraction and assay time) for the presence of free toxins (OA, DTX1, DTX2). DTX3 detection could be included with the addition of a hydrolysis procedure. No matrix effects were observed from the species evaluated (mussels, scallops, oysters, and clams). Results from naturally Contaminated samples (n = 72) indicated no false compliant results and no false noncompliant results at <50% MPL. Thus, the development of a new low-cost but highly effective tool for monitoring a range of important phycotoxins has been demonstrated.
-
new insights into the causes of human illness due to consumption of azaspiracid Contaminated Shellfish
Scientific Reports, 2015Co-Authors: Olivier P Chevallier, Katrina Campbell, Luis M Botana, Stewart F Graham, Eva Alonso, C Duffy, J Silke, Christopher T. ElliottAbstract:Azaspiracid (AZA) poisoning was unknown until 1995 when Shellfish harvested in Ireland caused illness manifesting by vomiting and diarrhoea. Further in vivo/vitro studies showed neurotoxicity linked with AZA exposure. However, the biological target of the toxin which will help explain such potent neurological activity is still unknown. A region of Irish coastline was selected and Shellfish were sampled and tested for AZA using mass spectrometry. An outbreak was identified in 2010 and samples collected before and after the contamination episode were compared for their metabolite profile using high resolution mass spectrometry. Twenty eight ions were identified at higher concentration in the Contaminated samples. Stringent bioinformatic analysis revealed putative identifications for seven compounds including, glutarylcarnitine, a glutaric acid metabolite. Glutaric acid, the parent compound linked with human neurological manifestations was subjected to toxicological investigations but was found to have no specific effect on the sodium channel (as was the case with AZA). However in combination, glutaric acid (1mM) and azaspiracid (50nM) inhibited the activity of the sodium channel by over 50%. Glutaric acid was subsequently detected in all Shellfish employed in the study. For the first time a viable mechanism for how AZA manifests itself as a toxin is presented.
-
paralytic Shellfish poisoning detection by surface plasmon resonance based biosensors in Shellfish matrixes
Analytical Chemistry, 2007Co-Authors: Eva S Fonfria, Katrina Campbell, Kentaro Kawatsu, Christopher T. Elliott, Natalia Vilariño, Simon A Haughey, Begona Bengigirey, Juan M Vieites, Luis M BotanaAbstract:The detection of paralytic Shellfish poisoning (PSP) toxins in Contaminated Shellfish is essential for human health preservation. Ethical and technical reasons have prompted the search for new detection procedures as an alternative to the mouse bioassay. On the basis of the detection of molecular interactions by surface plasmon resonance (SPR) biosensors, an inhibition assay was developed using an anti-GTX2/3 antibody (GT13-A) and a saxitoxin-CM5 chip. This assay allowed for quantification of saxitoxin (STX), decarbamoyl saxitoxin (dcSTX), gonyautoxin 2,3 (GTX2/3), decarbamoyl gonyautoxin 2,3 (dcGTX2/3), gonyautoxin 5 (GTX5), and C 1,2 (C1/2) at concentrations from 2 to 50 ng/mL. The interference of five Shellfish matrixes with the inhibition assay was analyzed. Mussels, clams, cockles, scallops, and oysters were extracted with five published methods. Ethanol extracts and acetic acid/heat extracts (AOAC Lawrence method) performed adequately in terms of surface regeneration and baseline interference, did n...
Jordi Molgo - One of the best experts on this subject based on the ideXlab platform.
-
synthetic pinnatoxins a and g reversibly block mouse skeletal neuromuscular transmission in vivo and in vitro
Marine Drugs, 2019Co-Authors: Evelyne Benoit, Rómulo Aráoz, Bogdan I Iorga, Denis Servent, Aurelie Couesnon, Jiri Lindovsky, Armen Zakarian, Jordi MolgoAbstract:Pinnatoxins (PnTXs) A-H constitute an emerging family belonging to the cyclic imine group of phycotoxins. Interest has been focused on these fast-acting and highly-potent toxins because they are widely found in Contaminated Shellfish. Despite their highly complex molecular structure, PnTXs have been chemically synthetized and demonstrated to act on various nicotinic acetylcholine receptor (nAChR) subtypes. In the present work, PnTX-A, PnTX-G and analogue, obtained by chemical synthesis with a high degree of purity (>98%), have been studied in vivo and in vitro on adult mouse and isolated nerve-muscle preparations expressing the mature muscle-type (α1)2β1δe nAChR. The results show that PnTX-A and G acted on the neuromuscular system of anesthetized mice and blocked the compound muscle action potential (CMAP) in a dose- and time-dependent manner, using a minimally invasive electrophysiological method. The CMAP block produced by both toxins in vivo was reversible within 6-8 h. PnTX-A and G, applied to isolated extensor digitorum longus nerve-muscle preparations, blocked reversibly isometric twitches evoked by nerve stimulation. The action of PnTX-A was reversed by 3,4-diaminopyridine. Both toxins exerted no direct action on muscle fibers, as revealed by direct muscle stimulation. PnTX-A and G blocked synaptic transmission at mouse neuromuscular junctions and PnTX-A amino ketone analogue (containing an open form of the imine ring) had no effect on neuromuscular transmission. These results indicate the importance of the cyclic imine for interacting with the adult mammalian muscle-type nAChR. Modeling and docking studies revealed molecular determinants responsible for the interaction of PnTXs with the muscle-type nAChR.
-
Synthetic Pinnatoxins A and G Reversibly Block Mouse Skeletal Neuromuscular Transmission In Vivo and In Vitro
MDPI AG, 2019Co-Authors: Evelyne Benoit, Rómulo Aráoz, Bogdan I Iorga, Denis Servent, Aurelie Couesnon, Jiri Lindovsky, Armen Zakarian, Jordi MolgoAbstract:Pinnatoxins (PnTXs) A-H constitute an emerging family belonging to the cyclic imine group of phycotoxins. Interest has been focused on these fast-acting and highly-potent toxins because they are widely found in Contaminated Shellfish. Despite their highly complex molecular structure, PnTXs have been chemically synthetized and demonstrated to act on various nicotinic acetylcholine receptor (nAChR) subtypes. In the present work, PnTX-A, PnTX-G and analogue, obtained by chemical synthesis with a high degree of purity (>98%), have been studied in vivo and in vitro on adult mouse and isolated nerve-muscle preparations expressing the mature muscle-type (α1)2β1δε nAChR. The results show that PnTX-A and G acted on the neuromuscular system of anesthetized mice and blocked the compound muscle action potential (CMAP) in a dose- and time-dependent manner, using a minimally invasive electrophysiological method. The CMAP block produced by both toxins in vivo was reversible within 6−8 h. PnTX-A and G, applied to isolated extensor digitorum longus nerve-muscle preparations, blocked reversibly isometric twitches evoked by nerve stimulation. The action of PnTX-A was reversed by 3,4-diaminopyridine. Both toxins exerted no direct action on muscle fibers, as revealed by direct muscle stimulation. PnTX-A and G blocked synaptic transmission at mouse neuromuscular junctions and PnTX-A amino ketone analogue (containing an open form of the imine ring) had no effect on neuromuscular transmission. These results indicate the importance of the cyclic imine for interacting with the adult mammalian muscle-type nAChR. Modeling and docking studies revealed molecular determinants responsible for the interaction of PnTXs with the muscle-type nAChR
-
The neurotoxic effect of 13, 19-didesmethyl and 13-desmethyl spirolide C phycotoxins is mainly mediated by nicotinic rather than muscarinic acetylcholine receptors.
Toxicological Sciences, 2015Co-Authors: Rómulo Aráoz, Evelyne Benoit, Jordi Molgo, Gilles Ouanounou, Bogdan I Iorga, Amélie Goudet, Doria Alili, Muriel Amar, Denis ServentAbstract:Spirolides are a large family of lipophilic marine toxins produced by dinoflagellates that have been detected in Contaminated Shellfish. Among them, 13,19-didesmethyl and 13-desmethyl spirolide C phycotoxins are widely distributed and their mode of action needs to be clearly defined. In order to further characterize the pharmacological profiles of these phycotoxins on various nicotinic acetylcholine receptor (nAChR) subtypes and to examine whether they act on muscarinic receptors (mAChRs), functional electrophysiological studies and competition binding experiments have been performed. While 13-desmethyl spirolide C interacted efficiently with sub-nanomolar affinities and low selectivity with muscular and neuronal nAChRs, 13,19-didesmethyl spirolide C was more selective of muscular and homopentameric a7 receptors and recognized only weakly neuronal heteropentameric receptors, especially the a4b2 subtype. Thus, the presence of an additional methyl group on the tetrahydropyran ring significantly modified the pharmacological profile of 13-desmethyl spirolide C by notably increasing its affinity on certain neuronal nAChRs. Structural explanations of this selectivity difference are proposed, based on molecular docking experiments modeling different spirolide-receptor complexes. In addition, the 2 spirolides interacted only with low micromolar affinities with the 5 mAChRs, highlighting that the toxicity of the spirolide C analogs is mainly due to their high inhibition potency on various peripheral and central nAChRs and not to their low ability to interact with mAChR subtypes.
-
toxic c17 sphinganine analogue mycotoxin contaminating tunisian mussels causes flaccid paralysis in rodents
Marine Drugs, 2013Co-Authors: Riadh Marrouchi, Evelyne Benoit, Jeanpierre Le Caer, Nawel Belayouni, Hafedh Belghith, Jordi Molgo, Riadh KharratAbstract:Severe toxicity was detected in mussels from Bizerte Lagoon (Northern Tunisia) using routine mouse bioassays for detecting diarrheic and paralytic toxins not associated to classical phytoplankton blooming. The atypical toxicity was characterized by rapid mouse death. The aim of the present work was to understand the basis of such toxicity. Bioassay-guided chromatographic separation and mass spectrometry were used to detect and characterize the fraction responsible for mussels’ toxicity. Only a C17-sphinganine analog mycotoxin (C17-SAMT), with a molecular mass of 287.289 Da, was found in Contaminated Shellfish. The doses of C17-SAMT that were lethal to 50% of mice were 750 and 150 μg/kg following intraperitoneal and intracerebroventricular injections, respectively, and 900 μg/kg following oral administration. The macroscopic general aspect of cultures and the morphological characteristics of the strains isolated from mussels revealed that the toxicity episodes were associated to the presence of marine microfungi (Fusarium sp., Aspergillus sp. and Trichoderma sp.) in Contaminated samples. The major in vivo effect of C17-SAMT on the mouse neuromuscular system was a dose- and time-dependent decrease of compound muscle action potential amplitude and an increased excitability threshold. In vitro, C17-SAMT caused a dose- and time-dependent block of directly- and indirectly-elicited isometric contraction of isolated mouse hemidiaphragms.