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Cultures of the mussel Mytilus galloprovincialis are frequently affected by accumulation of the amnesic shellfish poisoning toxin domoic acid (DA). This species is characterized by a fast uptake and release of the toxin. In this work, the main characteristics of the uptake mechanism have been studied by incubation of digestive gland thin slices in media with different composition and DA concentration. DA uptake seems to follow Michaelis–Menten kinetics, with a very high estimated KM (1722 µg DA mL−1) and a Vmax of 71.9 µg DA g−1 h−1, which is similar to those found for other amino acids in invertebrates. Replacement of NaCl from the incubation media by Cl-choline (Na+-free medium) did not significantly reduce the uptake, but replacement by sorbitol (Na+-free and Cl−-depleted medium) did. A new experiment replacing all chlorides with their equivalent gluconates (Na+- and Cl−-free medium) showed an important reduction in the uptake that should be attributed to the absence of chloride, pointing to a Na+-independent, Cl− (or anion-) dependent transporter. In media with Na+ and Cl−, neither decreasing the pH nor adding cyanide (a metabolic inhibitor) had significant effect on DA uptake, suggesting that the transport mechanism is not H+- or ATP-dependent. In a chloride depleted medium, lowering pH or adding CN increased the uptake, suggesting that other anions could, at least partially, substitute chloride.
Juan Blanco; Carmen Mariño; Helena Martín; Gonzalo Álvarez; Araceli Rossignoli. Characterization of the Domoic Acid Uptake Mechanism of the Mussel (Mytilus galloprovincialis) Digestive Gland. Toxins 2021, 13, 458 .
AMA StyleJuan Blanco, Carmen Mariño, Helena Martín, Gonzalo Álvarez, Araceli Rossignoli. Characterization of the Domoic Acid Uptake Mechanism of the Mussel (Mytilus galloprovincialis) Digestive Gland. Toxins. 2021; 13 (7):458.
Chicago/Turabian StyleJuan Blanco; Carmen Mariño; Helena Martín; Gonzalo Álvarez; Araceli Rossignoli. 2021. "Characterization of the Domoic Acid Uptake Mechanism of the Mussel (Mytilus galloprovincialis) Digestive Gland." Toxins 13, no. 7: 458.
The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained from Paracas Bay, an important zone for scallop (Argopecten purpuratus) aquaculture in Peru. Morphological analysis revealed the presence of the genus Pseudo-nitzschia, which was isolated and cultivated in laboratory conditions. Subsequently, the monoclonal cultures were observed by scanning electron microscopy (SEM), and identified as P. multistriata, based on both the morphological characteristics, and internal transcribed spacers region (ITS2) sequence phylogenetic analysis. Toxin analysis using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) revealed the presence of domoic acid (DA) with an estimated amount of 0.004 to 0.010 pg cell−1. This is the first report of DA from the coastal waters of Peru and its detection in P. multistriata indicates that it is a potential risk. Based on our results, routine monitoring of this genus should be considered in order to ensure public health.
Cecil Tenorio; Gonzalo Álvarez; Sonia Quijano-Scheggia; Melissa Perez-Alania; Natalia Arakaki; Michael Araya; Francisco Álvarez; Juan Blanco; Eduardo Uribe. First Report of Domoic Acid Production from Pseudo-nitzschia multistriata in Paracas Bay (Peru). Toxins 2021, 13, 408 .
AMA StyleCecil Tenorio, Gonzalo Álvarez, Sonia Quijano-Scheggia, Melissa Perez-Alania, Natalia Arakaki, Michael Araya, Francisco Álvarez, Juan Blanco, Eduardo Uribe. First Report of Domoic Acid Production from Pseudo-nitzschia multistriata in Paracas Bay (Peru). Toxins. 2021; 13 (6):408.
Chicago/Turabian StyleCecil Tenorio; Gonzalo Álvarez; Sonia Quijano-Scheggia; Melissa Perez-Alania; Natalia Arakaki; Michael Araya; Francisco Álvarez; Juan Blanco; Eduardo Uribe. 2021. "First Report of Domoic Acid Production from Pseudo-nitzschia multistriata in Paracas Bay (Peru)." Toxins 13, no. 6: 408.
Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and co-occurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d−1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L−1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 – 25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L−1 just above the pycnocline) was characterized by fresher (salinity 17 – 20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile.
Ángela M. Baldrich; Iván Pérez-Santos; Gonzalo Álvarez; Beatriz Reguera; Concepción Fernández-Pena; Camilo Rodríguez-Villegas; Michael Araya; Francisco Álvarez; Facundo Barrera; Stéphane Karasiewicz; Patricio A. Díaz. Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord. Harmful Algae 2021, 103, 102010 .
AMA StyleÁngela M. Baldrich, Iván Pérez-Santos, Gonzalo Álvarez, Beatriz Reguera, Concepción Fernández-Pena, Camilo Rodríguez-Villegas, Michael Araya, Francisco Álvarez, Facundo Barrera, Stéphane Karasiewicz, Patricio A. Díaz. Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord. Harmful Algae. 2021; 103 ():102010.
Chicago/Turabian StyleÁngela M. Baldrich; Iván Pérez-Santos; Gonzalo Álvarez; Beatriz Reguera; Concepción Fernández-Pena; Camilo Rodríguez-Villegas; Michael Araya; Francisco Álvarez; Facundo Barrera; Stéphane Karasiewicz; Patricio A. Díaz. 2021. "Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord." Harmful Algae 103, no. : 102010.
Domoic acid (DA), the main toxin responsible for Amnesic Shellfish Poisoning, frequently affects the marine resources of Chile and other countries across the South Pacific, thus becoming a risk for human health. One of the affected resources is the scallop Argopecten purpuratus. Even though this species has a high commercial importance in Northern Chile and Peru, the characteristics of its DA depuration are not known. In this work, the DA depuration was studied by means of two experiments: one in controlled (laboratory) and another in natural conditions. All organs of A. purpuratus depurated the toxin very quickly in both experiments. In some organs, an increase or a very small decrease of toxin was detected in the early depuration steps. Several models were used to describe this kinetics. The one that included toxin transfer between organs and independent depuration from each organ was the model that best fit the data. It seems, therefore, that the DA in this species is quickly transferred from the digestive gland to all other organs, which release it into the environment. Physiological differences in the two experiments have been shown to have some effect on the depuration from each organ but the actual reasons are still unknown.
Gonzalo Álvarez; José Rengel; Michael Araya; Francisco Álvarez; Roberto Pino; Eduardo Uribe; Patricio Díaz; Araceli Rossignoli; Américo López-Rivera; Juan Blanco. Rapid Domoic Acid Depuration in the Scallop Argopecten purpuratus and Its Transfer from the Digestive Gland to Other Organs. Toxins 2020, 12, 698 .
AMA StyleGonzalo Álvarez, José Rengel, Michael Araya, Francisco Álvarez, Roberto Pino, Eduardo Uribe, Patricio Díaz, Araceli Rossignoli, Américo López-Rivera, Juan Blanco. Rapid Domoic Acid Depuration in the Scallop Argopecten purpuratus and Its Transfer from the Digestive Gland to Other Organs. Toxins. 2020; 12 (11):698.
Chicago/Turabian StyleGonzalo Álvarez; José Rengel; Michael Araya; Francisco Álvarez; Roberto Pino; Eduardo Uribe; Patricio Díaz; Araceli Rossignoli; Américo López-Rivera; Juan Blanco. 2020. "Rapid Domoic Acid Depuration in the Scallop Argopecten purpuratus and Its Transfer from the Digestive Gland to Other Organs." Toxins 12, no. 11: 698.
The king scallop Pecten maximus retains the amnesic shellfish poisoning toxin, domoic acid (DA), for a long time. Most of the toxin is accumulated in the digestive gland, but this organ contains several cell types whose contribution to the accumulation of the toxin is unknown. Determining the time-course of the depuration by analyzing whole organs is difficult because the inter-individual variability is high. A sampling method, using biopsies of the digestive gland, has been developed. This method allows for repetitive sampling of the same scallop, but the representativeness of the samples obtained in this way needs to be validated. In this work, we found that the distribution of DA in the digestive gland of the scallops is mostly homogeneous. Only the area closest to the gonad, and especially its outer portion, had a lower concentration than the other ones, probably due to a transfer of the toxin to the intestinal loop. Samples obtained by biopsies can therefore be considered to be representative. Most of the toxin was accumulated in large cells (mostly digestive cells), which could be due to differences during the toxin absorption or to the preferential depuration of the toxin from the small cells (mostly secretory).
Juan Blanco; Aida Mauríz; Gonzalo Álvarez. Distribution of Domoic Acid in the Digestive Gland of the King Scallop Pecten maximus. Toxins 2020, 12, 371 .
AMA StyleJuan Blanco, Aida Mauríz, Gonzalo Álvarez. Distribution of Domoic Acid in the Digestive Gland of the King Scallop Pecten maximus. Toxins. 2020; 12 (6):371.
Chicago/Turabian StyleJuan Blanco; Aida Mauríz; Gonzalo Álvarez. 2020. "Distribution of Domoic Acid in the Digestive Gland of the King Scallop Pecten maximus." Toxins 12, no. 6: 371.
Phalacroma rotundatum is a rare cosmopolitan heterotrophic dinoflagellate. This species, included in the IOC-UNESCO Taxonomic Reference List of Harmful Microalgae, may be a diarrhetic shellfish poisoning (DSP) toxin vector, but little is known about its ecophysiology and behavior. A vertical net haul collected during the austral summer of 2018 in Reloncaví Sound (Chilean Patagonia) revealed an unusually abundant population of P. rotundatum and prompted intensive 24 h sampling on 16-17 January to study the cell cycle and feeding behavior of this species. Hydrographic measurements from a buoy revealed the local characteristic estuarine circulation, with a brackish surface layer (salinity 26-28) separated from saltier, colder bottom waters by a pycnocline at a depth modulated by the tidal regime. A high proportion of P. rotundatum cells were packed with digestive vacuoles (peak of 70% at 14:00), and phased cell division (µ = 0.46 d-1) occurred 3 h after sunrise. The division time (TD) was 2 h. This is the first cell cycle study of P. rotundatum. The results here disagree with those of previous field studies that considered asynchronous division in some Dinophysis species to be related to heterotrophic feeding. They also question the very specific prey requirements, Tiarina fusus, reported for P. rotundatum in northern Europe.
Patricio A. Díaz; Iván Pérez-Santos; Gonzalo Álvarez; Michael Araya; Francisco Álvarez; Beatriz Reguera. Cell Cycle, Division Rate, and Feeding of the Heterotroph Phalacroma rotundatum in a Chilean Fjord. Microorganisms 2019, 7, 451 .
AMA StylePatricio A. Díaz, Iván Pérez-Santos, Gonzalo Álvarez, Michael Araya, Francisco Álvarez, Beatriz Reguera. Cell Cycle, Division Rate, and Feeding of the Heterotroph Phalacroma rotundatum in a Chilean Fjord. Microorganisms. 2019; 7 (10):451.
Chicago/Turabian StylePatricio A. Díaz; Iván Pérez-Santos; Gonzalo Álvarez; Michael Araya; Francisco Álvarez; Beatriz Reguera. 2019. "Cell Cycle, Division Rate, and Feeding of the Heterotroph Phalacroma rotundatum in a Chilean Fjord." Microorganisms 7, no. 10: 451.
In late February 2016, a harmful algal bloom (HAB) of Alexandrium catenella was detected in southern Chiloé, leading to the banning of shellfish harvesting in an extended geographical area (~500 km). On April 24, 2016, this bloom produced a massive beaching (an accumulation on the beach surface of dead or impaired organisms which were drifted ashore) of surf clams Mesodesma donacium in Cucao Bay, Chiloé. To determine the effect of paralytic shellfish poisoning (PSP) toxins in M. donacium, samples were taken from Cucao during the third massive beaching detected on May 3, 2016. Whole tissue toxicity evidence a high interindividual variability with values which ranged from 1008 to 8763 μg STX eq 100 g−1 and with a toxin profile dominated by GTX3, GTX1, GTX2, GTX4, and neoSTX. Individuals were dissected into digestive gland (DG), foot (FT), adductor muscle (MU), and other body fractions (OBF), and histopathological and toxin analyses were carried out on the obtained fractions. Some pathological conditions were observed in gill and digestive gland of 40–50% of the individuals that correspond to hemocyte aggregation and haemocytic infiltration, respectively. The most toxic tissue was DG (2221 μg STX eq 100 g−1), followed by OBF (710 μg STX eq 100 g−1), FT (297 μg STX eq 100 g−1), and MU (314 μg STX eq 100 g−1). The observed surf clam mortality seems to have been mainly due to the desiccation caused by the incapability of the clams to burrow. Considering the available information of the monitoring program and taking into account that this episode was the first detected along the open coast of the Pacific Ocean in southern Chiloé, it is very likely that the M. donacium population from Cucao Bay has not had a recurrent exposition to A. catenella and, consequently, that it has not been subjected to high selective pressure for PSP resistance. However, more research is needed to determine the effects of PSP toxins on behavioral and physiological responses, nerve sensitivity, and genetic/molecular basis for the resistance or sensitivity of M. donacium.
Gonzalo Álvarez; Patricio A. Díaz; Marcos Godoy; Michael Araya; Iranzu Ganuza; Roberto Pino; Francisco Álvarez; José Rengel; Cristina Hernández; Eduardo Uribe; Juan Blanco. Paralytic Shellfish Toxins in Surf Clams Mesodesma donacium during a Large Bloom of Alexandrium catenella Dinoflagellates Associated to an Intense Shellfish Mass Mortality. Toxins 2019, 11, 188 .
AMA StyleGonzalo Álvarez, Patricio A. Díaz, Marcos Godoy, Michael Araya, Iranzu Ganuza, Roberto Pino, Francisco Álvarez, José Rengel, Cristina Hernández, Eduardo Uribe, Juan Blanco. Paralytic Shellfish Toxins in Surf Clams Mesodesma donacium during a Large Bloom of Alexandrium catenella Dinoflagellates Associated to an Intense Shellfish Mass Mortality. Toxins. 2019; 11 (4):188.
Chicago/Turabian StyleGonzalo Álvarez; Patricio A. Díaz; Marcos Godoy; Michael Araya; Iranzu Ganuza; Roberto Pino; Francisco Álvarez; José Rengel; Cristina Hernández; Eduardo Uribe; Juan Blanco. 2019. "Paralytic Shellfish Toxins in Surf Clams Mesodesma donacium during a Large Bloom of Alexandrium catenella Dinoflagellates Associated to an Intense Shellfish Mass Mortality." Toxins 11, no. 4: 188.
Surf clams, Mesodesma donacium, were shown to accumulate toxins from Dinophysis acuminata blooms. Only pectenotoxin 2 (PTX2) and some of its derivatives were found, and no toxins from the okadaic acid group were detected. PTX2 seems to be transformed to PTX2 seco-acid (PTX2sa), which was found in concentrations more than ten-fold those of PTX2. The seco-acid was transformed to acyl-derivatives by esterification with different fatty acids. The estimated amount of these derivatives in the mollusks was much higher than that of PTX2. Most esters were originated by even carbon chain fatty acids, but some originated by odd carbon number were also found in noticeable concentrations. Some peaks of toxin in the bivalves did not coincide with those of Dinophysis abundance, suggesting that there were large differences in toxin content per cell among the populations that developed throughout the year. The observed depuration (from the digestive gland) was fast (more than 0.2 day−1), and was faster for PTX2 than for PTX2sa, which in turn was faster than that of esters of PTX2sa. PTX2 and PTX2sa were distributed nearly equally between the digestive gland and the remaining tissues, but less than 5% of the palmytoyl-esters were found outside the digestive gland.
Juan Blanco; Gonzalo Álvarez; José Rengel; Rosario Díaz; Carmen Mariño; Helena Martín; Eduardo Uribe. Accumulation and Biotransformation of Dinophysis Toxins by the Surf Clam Mesodesma donacium. Toxins 2018, 10, 314 .
AMA StyleJuan Blanco, Gonzalo Álvarez, José Rengel, Rosario Díaz, Carmen Mariño, Helena Martín, Eduardo Uribe. Accumulation and Biotransformation of Dinophysis Toxins by the Surf Clam Mesodesma donacium. Toxins. 2018; 10 (8):314.
Chicago/Turabian StyleJuan Blanco; Gonzalo Álvarez; José Rengel; Rosario Díaz; Carmen Mariño; Helena Martín; Eduardo Uribe. 2018. "Accumulation and Biotransformation of Dinophysis Toxins by the Surf Clam Mesodesma donacium." Toxins 10, no. 8: 314.
In summer 2009, during a survey in Bahía Mejillones, a dense bloom of a dinoflagellate from the genus Gonyaulax was detected, as well as the presence of yessotoxin. Phytoplankton samples were analyzed in detail by light and scanning electron microscopy (SEM), revealing the presence of Gonyaulax taylorii. Morphological examination showed that the cells in the bloom fit in Gonyaulax jollifei Murray et Whitting sensu Dodge, subsequently classified as Gonyaulax taylorii by Carbonell-Moore. In this context, some inconsistencies have been found in regard to the holotype; the plate 1”’ appears as two plates, 1‴ and 2‴, showing a suture that does not exist in Dodge’s figure of G. jollifei, from where the holotype was drawn, nor within the samples collected. Therefore, this plate has been originally described erroneously as two plates named 1”’ and 2”’ instead of only one named 1‴. After this correction, this species has five instead of six postcingular plates. For this reason, the description of this species must be emended. Phytoplankton net samples were found to contain yessotoxin and homoyessotoxin, with concentrations below 1 pg cell−1. The present study identifies, therefore, the dinoflagellate G. taylorii as a new source of yessotoxins.
Gonzalo Álvarez; Eduardo Uribe; Jorge Regueiro; Juan Blanco; Santiago Fraga. Gonyaulax taylorii , a new yessotoxins-producer dinoflagellate species from Chilean waters. Harmful Algae 2016, 58, 8 -15.
AMA StyleGonzalo Álvarez, Eduardo Uribe, Jorge Regueiro, Juan Blanco, Santiago Fraga. Gonyaulax taylorii , a new yessotoxins-producer dinoflagellate species from Chilean waters. Harmful Algae. 2016; 58 ():8-15.
Chicago/Turabian StyleGonzalo Álvarez; Eduardo Uribe; Jorge Regueiro; Juan Blanco; Santiago Fraga. 2016. "Gonyaulax taylorii , a new yessotoxins-producer dinoflagellate species from Chilean waters." Harmful Algae 58, no. : 8-15.
In northern Chile, domoic acid (DA) has been detected in several bivalve species. In Mesodesma donacium, one of the most important commercial species for local fishermen, no information is available on depuration, or on the anatomical distribution of this toxin and its potential use as a palliative measure to minimize the consequences of ASP outbreaks. Deputation of DA is very fast in M. donacium, and can be adequately described by means of a two-compartment model. The estimated rates for the first and second compartments were 1.27 d(-1) and 0.24 d(-1), respectively, with a transfer rate between compartments of 0.75. Having high depuration rates protects this species from being affected by Pseudo-nitzschia blooms for an extended period of time. Taking this into account, the time in which the bivalves are unsafe for consumers is very short, and therefore the economic losses that could result by the DA outbreaks in local fisheries should be moderate. In relation to anatomical distribution, at least during the uptake phase, the toxin was evenly distributed within the soft tissues, with a total toxin burden corresponding to 27%, 32% and 41% for Digestive Gland (DG), Foot (FT) and Other Body Fractions (OBF), respectively. Since the contribution of each organ to the toxin concentration is a function of both weight contribution and toxin burden, the pattern of toxin distribution showed the following trend: "all other body fractions" (OBF) > Foot (FT) > Digestive Gland (DG). Thus, the highest concentration of DA, with a contribution close to 72%, corresponds to the edible tissues (OBF + FT), while the DG (non-edible tissue) only contributes the remaining 28%. Consequently, in view of the anatomical distribution of domoic acid in M. donacium, the elimination of the digestive gland does not substantially reduce the toxicity of the final product and therefore selective evisceration would not improve their quality for human consumption.
Gonzalo Álvarez; Eduardo Uribe; Jorge Regueiro; Helena Martin; Teresa Gajardo; Lorena Jara; Juan Blanco. Depuration and anatomical distribution of domoic acid in the surf clam Mesodesma donacium. Toxicon 2015, 102, 1 -7.
AMA StyleGonzalo Álvarez, Eduardo Uribe, Jorge Regueiro, Helena Martin, Teresa Gajardo, Lorena Jara, Juan Blanco. Depuration and anatomical distribution of domoic acid in the surf clam Mesodesma donacium. Toxicon. 2015; 102 ():1-7.
Chicago/Turabian StyleGonzalo Álvarez; Eduardo Uribe; Jorge Regueiro; Helena Martin; Teresa Gajardo; Lorena Jara; Juan Blanco. 2015. "Depuration and anatomical distribution of domoic acid in the surf clam Mesodesma donacium." Toxicon 102, no. : 1-7.