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The content of free and hydrolyzed primary amino acids was determined for five species of microalgae: Haematococcus pluvialis, Skeletonema costatum, Arthrospira sp., Acutodesmus acuminatus, and Botryococcus braunii. The amino acid profile was determined using an automated HPLC-DAD reverse phase pre-column analysis method, which is described in detail. Acid hydrolysis using 6 M HCl and autoclaving at 120 °C for 2 h was validated using casein of bovine origin as standard. Nitrogen to protein conversion factors were calculated for each microalgae. Haematococcus pluvialis contains the least amount of free amino acids (38.8 ± 0.15 mg AA/100 g DW), while Arthrospira sp. shows the most enriched free amino acid profile (316.1 ± 0,11 mg AA/100 g DW). Skeletonema costatum shows the least amount of amino acids after hydrolysis with 5.09 ± 0.28 g AA/100 g DW while Arthrospira sp. achieves 27.76 ± 0.19 g AA/100 g DW. The total protein content and its relationship with the detected amino acid content are discussed.
Michael Araya; Samantha García; José Rengel; Sebastián Pizarro; Gonzalo Álvarez. Determination of free and protein amino acid content in microalgae by HPLC-DAD with pre-column derivatization and pressure hydrolysis. Marine Chemistry 2021, 234, 103999 .
AMA StyleMichael Araya, Samantha García, José Rengel, Sebastián Pizarro, Gonzalo Álvarez. Determination of free and protein amino acid content in microalgae by HPLC-DAD with pre-column derivatization and pressure hydrolysis. Marine Chemistry. 2021; 234 ():103999.
Chicago/Turabian StyleMichael Araya; Samantha García; José Rengel; Sebastián Pizarro; Gonzalo Álvarez. 2021. "Determination of free and protein amino acid content in microalgae by HPLC-DAD with pre-column derivatization and pressure hydrolysis." Marine Chemistry 234, no. : 103999.
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.
Seaweed processing generates liquid fraction residual that could be used as a low-cost nutrient source for microbial production of metabolites. The Rhodotorula strain is able to produce antimicrobial compounds known as sophorolipids. Our aim was to evaluate sophorolipid production, with antibacterial activity, by marine Rhodotorula rubra using liquid fraction residual (LFR) from the brown seaweed Macrocystis pyrifera as the nutrient source. LFR having a composition of 32% w/w carbohydrate, 1% w/w lipids, 15% w/w protein and 52% w/w ash. The best culture condition for sophorolipid production was LFR 40% v/v, without yeast extract, artificial seawater 80% v/v at 15 °C by 3 growth days, with the antibacterial activity of 24.4 ± 3.1 % on Escherichia coli and 21.1 ± 3.8 % on Staphylococcus aureus. It was possible to identify mono-acetylated acidic and methyl ester acidic sophorolipid. These compounds possess potential as pathogen controllers for application in the food industry.
Allison Leyton; Michael Araya; Fadia Tala; Liset Flores; María Lienqueo; Carolina Shene. Macrocystis pyrifera Extract Residual as Nutrient Source for the Production of Sophorolipids Compounds by Marine Yeast Rhodotorula rubra. Molecules 2021, 26, 2355 .
AMA StyleAllison Leyton, Michael Araya, Fadia Tala, Liset Flores, María Lienqueo, Carolina Shene. Macrocystis pyrifera Extract Residual as Nutrient Source for the Production of Sophorolipids Compounds by Marine Yeast Rhodotorula rubra. Molecules. 2021; 26 (8):2355.
Chicago/Turabian StyleAllison Leyton; Michael Araya; Fadia Tala; Liset Flores; María Lienqueo; Carolina Shene. 2021. "Macrocystis pyrifera Extract Residual as Nutrient Source for the Production of Sophorolipids Compounds by Marine Yeast Rhodotorula rubra." Molecules 26, no. 8: 2355.
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.
A new spectrophotometric method has been developed for the determination of iodate through thein situproduction of iodine.
Michael Araya; Samantha García; Sebastián Pizarro. Iodine and iodate determination by a new spectrophotometric method usingN,N-dimethyl-p-phenylenediamine, validated in veterinary supplements and table salt. Analytical Methods 2019, 12, 205 -211.
AMA StyleMichael Araya, Samantha García, Sebastián Pizarro. Iodine and iodate determination by a new spectrophotometric method usingN,N-dimethyl-p-phenylenediamine, validated in veterinary supplements and table salt. Analytical Methods. 2019; 12 (2):205-211.
Chicago/Turabian StyleMichael Araya; Samantha García; Sebastián Pizarro. 2019. "Iodine and iodate determination by a new spectrophotometric method usingN,N-dimethyl-p-phenylenediamine, validated in veterinary supplements and table salt." Analytical Methods 12, no. 2: 205-211.
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.
Six aristolochic acids were identified in the Chilean species Aristolochia chilensis using high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) and subsequent confirmation with mass spectrometry (MS). The fractions of each signal were collected and injected directly into an Orbitrap mass detector model Q Exactive Focus (Thermo Scientific). The acids extraction was done with 0.10–0.50 g of lyophilized and pulverized sample and concentrated in Soxhlet extraction equipment. The liquid-liquid separations and a subsequent solid phase extraction (SPE) C18 were performed using 100 µL of the extract that contains the aristolochic acids present in the Aristolochia chilensis plant. The HPLC conditions used a single mobile phase acetonitrile : water (1 : 1) acidified with 0.1% acetic acid and an isocratic elution to 1 mL·min−1. The column InertSustain C18 250 × 4.6 mm and 3 µm was used, the injection volume was 20 µL, and the time of run was reduced to 15 min. Calibration curves were constructed with r 2 being 0.9997. The quantification limit for AAI was 0.138 ± 0.010 µg/mL, and for AAII, it was 0.558 ± 0.042 µg/mL.
Michael Araya; Samantha García; Marcia González-Teuber. Rapid Identification and Simultaneous Quantification of Aristolochic Acids by HPLC-DAD and Confirmations by MS in Aristolochia chilensis Using a Limited Biomass. Journal of Analytical Methods in Chemistry 2018, 2018, 1 -8.
AMA StyleMichael Araya, Samantha García, Marcia González-Teuber. Rapid Identification and Simultaneous Quantification of Aristolochic Acids by HPLC-DAD and Confirmations by MS in Aristolochia chilensis Using a Limited Biomass. Journal of Analytical Methods in Chemistry. 2018; 2018 ():1-8.
Chicago/Turabian StyleMichael Araya; Samantha García; Marcia González-Teuber. 2018. "Rapid Identification and Simultaneous Quantification of Aristolochic Acids by HPLC-DAD and Confirmations by MS in Aristolochia chilensis Using a Limited Biomass." Journal of Analytical Methods in Chemistry 2018, no. : 1-8.