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Gambierdiscus species are the producers of the marine toxins ciguatoxins and maitotoxins which cause worldwide human intoxications recognized as Ciguatera Fish Poisoning. A deep chemical investigation of a cultured strain of G. belizeanus, collected in the Caribbean Sea, led to the identification of a structural homologue of the recently described gambierone isolated from the same strain. The structure was elucidated mainly by comparison of NMR and MS data with those of gambierone and ascertained by 2D NMR data analyses. Gratifyingly, a close inspection of the MS data of the new 44-methylgambierone suggests that this toxin would actually correspond to the structure of maitotoxin-3 (MTX3, m/z 1039.4957 for the protonated adduct) detected in 1994 in a Pacific strain of Gambierdiscus and recently shown in routine monitoring programs. Therefore, this work provides for the first time the chemical identification of the MTX3 molecule by NMR. Furthermore, biological data confirmed the similar activities of both gambierone and 44-methylgambierone. Both gambierone and MTX3 induced a small increase in the cytosolic calcium concentration but only MTX3 caused cell cytotoxicity at micromolar concentrations. Moreover, chronic exposure of human cortical neurons to either gambierone or MTX3 altered the expression of ionotropic glutamate receptors, an effect already described before for the synthetic ciguatoxin CTX3C. However, even when gambierone and MTX3 affected glutamate receptor expression in a similar manner their effect on receptor expression differed from that of CTX3C, since both toxins decreased AMPA receptor levels while increasing N-methyl-d-aspartate (NMDA) receptor protein. Thus, further studies should be pursued to clarify the similarities and differences in the biological activity between the known ciguatoxins and the new identified molecule as well as its contribution to the neurological symptoms of ciguatera.
Andrea Boente-Juncal; Mercedes Álvarez; Álvaro Antelo; Inés Rodríguez; Kevin Calabro; Carmen Vale; Olivier P. Thomas; Luis M. Botana. Structure Elucidation and Biological Evaluation of Maitotoxin-3, a Homologue of Gambierone, from Gambierdiscus belizeanus. Toxins 2019, 11, 79 .
AMA StyleAndrea Boente-Juncal, Mercedes Álvarez, Álvaro Antelo, Inés Rodríguez, Kevin Calabro, Carmen Vale, Olivier P. Thomas, Luis M. Botana. Structure Elucidation and Biological Evaluation of Maitotoxin-3, a Homologue of Gambierone, from Gambierdiscus belizeanus. Toxins. 2019; 11 (2):79.
Chicago/Turabian StyleAndrea Boente-Juncal; Mercedes Álvarez; Álvaro Antelo; Inés Rodríguez; Kevin Calabro; Carmen Vale; Olivier P. Thomas; Luis M. Botana. 2019. "Structure Elucidation and Biological Evaluation of Maitotoxin-3, a Homologue of Gambierone, from Gambierdiscus belizeanus." Toxins 11, no. 2: 79.
Although paralytic shellfish toxins (PSTs) have traditionally been analyzed by liquid chromatography with either pre- or post-column derivatization, and these methods have been validated successfully through inter-laboratory studies, mass spectrometry methods have also been described in literature for use in monitoring programs. However, methods using liquid chromatography coupled with mass spectrometry (LC-MS) need to be improved in terms of sensitivity, analyte recovery and retention time stability because of undesirable matrix effects. Furthermore, tetrodotoxin (TTX) has been found in northern European bivalves, so it is important to analyze TTX compounds alongside PSTs because characteristics of their toxicity are similar. This paper describes, for the first time, a chemical method that allows determination of PSTs, both hydrophilic and hydrophobic, alongside TTX and its analogue 4,9-anhydro tetrodotoxin (4,9-anhTTX) with LC-MS/MS using a Hypercarb® column. The method was validated for 13 hydrophilic PSTs and TTXs and was able to discriminate six hydrophobic PSTs in 20 minutes. The method was developed for four shellfish matrices: mussel (Mytillus galloprovincialis), clam (Ruditapes decussatus), scallop (Pecten maximus) and oyster (Ostrae edulis). Clean-up procedure used in this work allowed us to obtain good results for validation parameters for both PSTs and TTXs. No standards were available so strains of Gymnodinium catenatum (G. catenatum)were used instead.
Veronica Rey; Ana M. Botana; Alvaro Antelo; Mercedes Alvarez; Luis M. Botana. Rapid analysis of paralytic shellfish toxins and tetrodotoxins by liquid chromatography-tandem mass spectrometry using a porous graphitic carbon column. Food Chemistry 2018, 269, 166 -172.
AMA StyleVeronica Rey, Ana M. Botana, Alvaro Antelo, Mercedes Alvarez, Luis M. Botana. Rapid analysis of paralytic shellfish toxins and tetrodotoxins by liquid chromatography-tandem mass spectrometry using a porous graphitic carbon column. Food Chemistry. 2018; 269 ():166-172.
Chicago/Turabian StyleVeronica Rey; Ana M. Botana; Alvaro Antelo; Mercedes Alvarez; Luis M. Botana. 2018. "Rapid analysis of paralytic shellfish toxins and tetrodotoxins by liquid chromatography-tandem mass spectrometry using a porous graphitic carbon column." Food Chemistry 269, no. : 166-172.
Tetrodotoxin (TTX) is starting to appear in molluscs from the European waters and is a hazard to seafood consumers. This toxin blocks sodium channels resulting in neuromuscular paralysis and even death. As a part of the risk assessment process leading to a safe seafood level for TTX, oral toxicity data are required. In this study, a 4-level Up and Down Procedure was designed in order to determine for the first time the oral lethal dose 50 (LD50) and the No Observed Adverse Effect Level (NOAEL) in mice by using an accurate well-characterized TTX standard.
Paula Abal; M. Carmen Louzao; Alvaro Antelo; Mercedes Alvarez; Eva Cagide; Natalia Vilariño; Mercedes R. Vieytes; Luis M. Botana. Acute Oral Toxicity of Tetrodotoxin in Mice: Determination of Lethal Dose 50 (LD50) and No Observed Adverse Effect Level (NOAEL). Toxins 2017, 9, 75 .
AMA StylePaula Abal, M. Carmen Louzao, Alvaro Antelo, Mercedes Alvarez, Eva Cagide, Natalia Vilariño, Mercedes R. Vieytes, Luis M. Botana. Acute Oral Toxicity of Tetrodotoxin in Mice: Determination of Lethal Dose 50 (LD50) and No Observed Adverse Effect Level (NOAEL). Toxins. 2017; 9 (3):75.
Chicago/Turabian StylePaula Abal; M. Carmen Louzao; Alvaro Antelo; Mercedes Alvarez; Eva Cagide; Natalia Vilariño; Mercedes R. Vieytes; Luis M. Botana. 2017. "Acute Oral Toxicity of Tetrodotoxin in Mice: Determination of Lethal Dose 50 (LD50) and No Observed Adverse Effect Level (NOAEL)." Toxins 9, no. 3: 75.
Paralytic Shellfish Toxins (PSTs) are polar analytes, most of them with positive charges resulting in a charge-induced dipole at the graphene surface when they approach to it. Graphene is a novel material with great potentials to be used as sorbent due to its ultrahigh surface area. Herein, we perform the simulation about the retention mechanism of PSTs on the graphene through Merck Molecular Force Field (MMFF94) minimizations. The overall retention on graphene is a combination of two mechanisms: - Adsorption: The strength of analyte interactions with graphene is largely dependent on the molecular area in contact with the graphene surface, and also on the type and positioning of the functional groups in relation to the graphene surface at the points of contact. - Charge induced interactions of a polar analyte with the polarizable surface of graphene: when the polar group with apermanent dipole approaches the surface, an induced dipole is formed, increasing the attraction between the analyte and graphene surface. Computational results were compared with those obtained after elution using a HPLC-Hypercarb column: they showed a good correlation pattern where it was seen that the theoretical model exhibited the potential of graphene as an excellent sorbent material for saxitoxin and analogues. Hypercarb model: elution order: (shorter retention time) dcSTX < NEO < STX < GTX5 < GTX3 < C2 < GTX2 < C1 (longer retention time). Merck Molecular Force Field (MMFF94) model, interaction energy values order: (minor complex energy) dcSTX < STX < NEO < GTX5 < GTX3 < GTX2 < C2 < C1 (mayor complex energy)
Álvaro Antelo; Ana M. Botana; Veronica Rey; Mercedes Álvarez; Luis Botana. Computational model of adsorption for paralytic shellfish poisoning toxins (PSTs) on graphene surface. Proceedings of The 20th International Electronic Conference on Synthetic Organic Chemistry 2016, 1 .
AMA StyleÁlvaro Antelo, Ana M. Botana, Veronica Rey, Mercedes Álvarez, Luis Botana. Computational model of adsorption for paralytic shellfish poisoning toxins (PSTs) on graphene surface. Proceedings of The 20th International Electronic Conference on Synthetic Organic Chemistry. 2016; ():1.
Chicago/Turabian StyleÁlvaro Antelo; Ana M. Botana; Veronica Rey; Mercedes Álvarez; Luis Botana. 2016. "Computational model of adsorption for paralytic shellfish poisoning toxins (PSTs) on graphene surface." Proceedings of The 20th International Electronic Conference on Synthetic Organic Chemistry , no. : 1.
Paralytic shellfish toxins (PST) traditionally have been analyzed by liquid chromatography with either pre- or post-column derivatization and always with a silica-based stationary phase. This technique resulted in different methods that need more than one run to analyze the toxins. Furthermore, tetrodotoxin (TTX) was recently found in bivalves of northward locations in Europe due to climate change, so it is important to analyze it along with PST because their signs of toxicity are similar in the bioassay. The methods described here detail a new approach to eliminate different runs, by using a new porous graphitic carbon stationary phase. Firstly we describe the separation of 13 PST that belong to different groups, taking into account the side-chains of substituents, in one single run of less than 30 min with good reproducibility. The method was assayed in four shellfish matrices: mussel (Mytillus galloprovincialis), clam (Pecten maximus), scallop (Ruditapes decussatus) and oyster (Ostrea edulis). The results for all of the parameters studied are provided, and the detection limits for the majority of toxins were improved with regard to previous liquid chromatography methods: the lowest values were those for decarbamoyl-gonyautoxin 2 (dcGTX2) and gonyautoxin 2 (GTX2) in mussel (0.0001 mg saxitoxin (STX)·diHCl kg−1 for each toxin), decarbamoyl-saxitoxin (dcSTX) in clam (0.0003 mg STX·diHCl kg−1), N-sulfocarbamoyl-gonyautoxins 2 and 3 (C1 and C2) in scallop (0.0001 mg STX·diHCl kg−1 for each toxin) and dcSTX (0.0003 mg STX·diHCl kg−1 ) in oyster; gonyautoxin 2 (GTX2) showed the highest limit of detection in oyster (0.0366 mg STX·diHCl kg−1). Secondly, we propose a modification of the method for the simultaneous analysis of PST and TTX, with some minor changes in the solvent gradient, although the detection limit for TTX does not allow its use nowadays for regulatory purposes.
Veronica Rey; Ana M. Botana; Mercedes Alvarez; Alvaro Antelo; Luis M. Botana. Liquid Chromatography with a Fluorimetric Detection Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin Based on a Porous Graphitic Carbon Column. Toxins 2016, 8, 196 .
AMA StyleVeronica Rey, Ana M. Botana, Mercedes Alvarez, Alvaro Antelo, Luis M. Botana. Liquid Chromatography with a Fluorimetric Detection Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin Based on a Porous Graphitic Carbon Column. Toxins. 2016; 8 (7):196.
Chicago/Turabian StyleVeronica Rey; Ana M. Botana; Mercedes Alvarez; Alvaro Antelo; Luis M. Botana. 2016. "Liquid Chromatography with a Fluorimetric Detection Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin Based on a Porous Graphitic Carbon Column." Toxins 8, no. 7: 196.
This study explores the effect of laboratory and industrial steaming on mussels with toxin concentrations above and below the legal limit. We used mild conditions for steaming, 100 °C for 5 min in industrial processing, and up to 20 min in small-scale laboratory steaming. Also, we studied the effect of heat on the toxin concentration of mussels obtained from two different locations and the effect of heat on the levels of dinophysistoxins 3 (DTX3) in both the mussel matrix and in pure form (7-O-palmitoyl okadaic ester and 7-O-palmytoleyl okadaic ester). The results show that the loss of water due to steaming was very small with a maximum of 9.5%, that the toxin content remained unchanged with no concentration effect or increase in toxicity, and that dinophysistoxins 3 was hydrolyzed or degraded to a certain extent under heat treatment. The use of liquid-certified matrix showed a 55% decrease of dinophysistoxins 3 after 10 min steaming, and a 50% reduction in total toxicity after treatment with an autoclave (121 °C for 20 min).
Inés Rodríguez; Amparo Alfonso; Alvaro Antelo; Mercedes Alvarez; Luis M. Botana. Evaluation of the Impact of Mild Steaming and Heat Treatment on the Concentration of Okadaic Acid, Dinophysistoxin-2 and Dinophysistoxin-3 in Mussels. Toxins 2016, 8, 175 .
AMA StyleInés Rodríguez, Amparo Alfonso, Alvaro Antelo, Mercedes Alvarez, Luis M. Botana. Evaluation of the Impact of Mild Steaming and Heat Treatment on the Concentration of Okadaic Acid, Dinophysistoxin-2 and Dinophysistoxin-3 in Mussels. Toxins. 2016; 8 (6):175.
Chicago/Turabian StyleInés Rodríguez; Amparo Alfonso; Alvaro Antelo; Mercedes Alvarez; Luis M. Botana. 2016. "Evaluation of the Impact of Mild Steaming and Heat Treatment on the Concentration of Okadaic Acid, Dinophysistoxin-2 and Dinophysistoxin-3 in Mussels." Toxins 8, no. 6: 175.