Examinando por Autor "Rivas, Jorge"
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Ítem A theoretical structure-affinity relationship study of some cannabinoid derivatives(Sociedad Chilena de Química, 2008) Gómez-Jeria, Juan S.; Soto-Morales, Francisco; Rivas, Jorge; Sotomayor, AlejandraA ZINDO/1 quantum-chemical structure-affinity relationship study with the KPG model is presented for the in vitro interaction of a group of classical, indole-derived and aminoalkylindole-derived cannabinoids with CB and CB2 receptors. From this work the following conclusions are obtained. CB and CB2 CB2 receptor affinities are regulated by different mechanisms involving orbital and charge control. Nevertheless CB and CB2 classical ligands share three common features: a hydrogen bond to a lysine (for CB ) or serine (for CB), a fully aromatic ring and a branched carbon side chain. In the case of indole-derived and aminoalkylindole-derived cannabinoids orientation and alignment rules have been defined as a basis for the comparison of noncongeneric molecules. In this way it was possible to associate the location of molecular fragments of these systems with known molecular systems such as classical cannabinoids. For aminoalkyhndoles we have proposed the locus with which they bind to a second receptor site that is available to WIN-55212-2 but not to classical cannabinoids. On the basis of our results we propose a new molecule that should help to discriminate between the above two receptor sites.Ítem Assessment of the independent and combined effects of copper and polycyclic aromatic hydrocarbons on gametogenesis and sporophyte development of the kelp Lessonia spicata (Phaeophyceae, Ochrophyta)(Springer Science and Business Media B.V., 2021-12) Espinoza‑González, Camila; Meynard, Andrés; Núñez, Alejandra; Castañeda, Francisco; Oyarzo‑Miranda, Carolina; Latorre‑Padilla, Nicolás; Rivas, Jorge; Contreras‑Porcia, LorettoCoastal shores near the industrial park of Quintero Bay in central Chile exhibit increasing concentrations of copper (Cu) and polycyclic aromatic hydrocarbons (PAHs), well above international standards. This raises concern about their combined toxic effects on early development stages of kelps. Accordingly, we aimed to assess more accurately the independent and combined effects of Cu and PAHs on gametogenesis and sporophyte development in the kelp Lessonia spicata from central Chile by in vitro cultivation. Independent Cu and PAH trials were performed using increasing nominal concentrations of Cu and PAHs in the ranges 0.8–200 µg L−1 and 0.05–100 µg L−1, respectively. Cu and PAH median effective concentrations (EC50) on gametogenesis and early sporophyte formation were calculated using DRC in the R environment. Then, combined EC50 Cu + PAH trials were conducted to determine their effects on gametogenesis and sporophyte formation. Cu EC50 values on gametogenesis and sporophyte formation were up to three orders of magnitude lower than EC50 reported previously on spore germination in kelps. The gametogenesis (EC50 = 1.39 μg L−1) was more sensitive to Cu than sporophyte formation (EC50 = 11 μg L−1). Inversely, sporophyte formation (EC50 = 0.04 μg L−1) was more sensitive to PAHs (EC50 = 0.11 μg L−1). Considering the entire exposure period, the combined EC50 Cu + PAH exposure was the most harmful and rapid for L. spicata microscopic stages, especially the synergistic effect on early sporophytes. This highlights the need to acquire an integrated knowledge of the seasonal variation of pollutants and their combination on highly intervened coasts.Ítem Coastal pollution from the industrial park Quintero bay of central Chile: Effects on abundance, morphology, and development of the kelp Lessonia spicata (Phaeophyceae)(Public Library of Science, 2020-10) Oyarzo-Miranda, Carolina; Latorre, Nicolás; Meynard, Andrés; Rivas, Jorge; Bulboa, Cristian; Contreras-Porcia, LorettoThe industrial park of Quintero Bay (QB) in the central coast of Chile was established in the 1960s, presents high levels of pollution due to the industrial activity, and it is known as one of the five Chilean “sacrifice zones”. Lessonia spicata is the most important habitat-forming kelp species in the intertidal along the central and south shores of Chile, and currently there are no morphometric and population studies of L. spicata (or other seaweed species) nor studies about the effects of pollution on its development in QB and neighbouring sites. In this context, the aims of this study were (i) to register the abundance and morphological features of L. spicata populations from Ventanas, Horcón and Cachagua (sites with different pollution histories and located only up to 40 km from the QB); ii) to determine the heavy metals (HMs) concentration in seawater and marine sediments; and (iii) to evaluate in vitro the effects of exposure to seawater from the three sampling sites on spore release and early developmental stages, up to the juvenile sporophyte. Results showed that the chronically exposed Ventanas kelp population had the smallest adult individuals in comparison with the other sites. Ventanas and Horcón registered high HMs concentration in the seawater and marine sediments exceeding the international permissible limits (e.g in seawater Cu 20–859 μg L-1; sediments Cu > 50,000 μg kg-1). Unexpectedly in Cachagua, a site often considered unpolluted, high concentrations of Cu and As were also registered in the seawater (859 and 1,484 μg L-1, respectively) and of As in marine sediments (20,895 μg kg-1). Exposure of gametophytes to the seawater from Ventanas resulted in a developmental delay compared to the other treatments; however, low sporophyte production was determined in all treatments. Our results indicate that QB, more notably Ventanas, induce highly negative effects on individual development, and consequently on seaweed populations, which suggest a long-term negative impact on the community structure of these marine zones. Furthermore, the high concentrations of HMs reported here at Cachagua suggest a recent expansion of pollution along the central coast of Chile, evidencing effects on the marine ecosystem health even on sites far from the pollution source. Copyright: © 2020 Oyarzo-Miranda et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Ítem Controlled cultivation of different stages of Pyropia orbicularis (Rhodophyta; Bangiales) from the South Pacific coast(Elsevier B.V., 2023-06) Piña, Florentina; Núñez, Alejandra; Araya, Matías; Rivas, Jorge; Hernández, Constanza; Bulboa, Cristian; Contreras-Porcia, LorettoThe species of the genus Pyropia have a diplohaplontic life cycle, in which there is a gametophytic phase (n) or blade, and a microscopic sporophytic phase (2n), known as conchocelis, as well as intermediate stages of development. Pyropia species, together with Porphyra species, belong to the group of the most commercialized and produced macroalgae worldwide, mainly due to their high nutritional value and high content of bioactive compounds with antioxidant and anti-inflammatory activity. The interest in cultivating and exploiting this marine resource has increased in recent years; nevertheless, despite the development of cultivation techniques and technologies for these species, there are still difficulties involved in their successful cultivation, mainly related to the great interspecific and intraspecific variability in the required culture conditions. In this work, we study the life cycle development of Pyropia orbicularis, a species endemic to the South Pacific, to determine the effect of abiotic culture parameters, such as the temperature and photoperiod, on the formation and development of early and late life cycle stages, such as conchocelis formation, cochoesporangial filaments, conchospore release and blade growth. Our results demonstrate that the conchocelis phase grew rapidly under 8:16 h (L:D) photo period conditions at both 15 ◦C and 20 ◦C. The lower temperatures favored the formation of conchosporangia and conchospores; the rate of their development was increased at 15 ◦C. The development of the blades in the suspended culture system was constant during the experimental period, generating blades of the same color and shape as those from natural populations. Our results reflect the adaptation of P. orbicularis to the seasonal environmental conditions it is exposed to and the importance of maintaining optimal abiotic parameters for the success of its culture. This work is the first to describe the full life cycle development of P. orbicularis under controlled conditions, which has important implications for commercial production.Ítem Determinación de hidrocarburos aromáticos policíclicos en lechuga comercial (lactuca sativa) por medio de cromatografía de gases-espectrometría de masas (CG-MS)(Universidad Andrés Bello, 2014) San Martín Ruíz, Macarena Andrea; Valenzuela, María Luisa; Rivas, Jorge; Facultad de Ciencias ExactasExisten una serie de contaminantes que son de gran preocupación ambiental, entre los cuales se encuentra los hidrocarburos aromáticos policíclicos (PAHs por sus siglas en inglés), que constituyen una clase de peligrosos compuestos orgánicos que constan de dos o más anillos aromáticos fusionados que presentan particular interés debido a sus características cancerígenas y/o mutagénicas. El ser humano está constantemente expuesto a este tipo de contaminantes por medio del aire, suelo, agua y principalmente por los alimentos. La Unión Europea y la Agencia para la Protección Ambiental de los Estados Unidos (EPA), considera 16 PAHs como prioritarios desde el punto de vista ambiental donde algunos de estos PAHs a nivel toxicológico son carcinogénicos. Es por esto, que es necesario realizar estudios para determinar el grado de contaminación que tienen los alimentos, por ejemplo los vegetales de hoja verde como la lechuga y espinaca. Para iniciar los estudios en esta temática, se utilizó como herramienta para la optimización de parámetros, un sistema multivariado factorial que tomó en cuenta tres variables para el proceso de extracción: tiempo de extracción, volumen de extracción y tipo de disolvente para dos tipos de técnicas de extracción: Asistida por ultrasonido y Soxhlet. Se trabajó con dos muestras de lechugas, milanesas y escarolas, las cuales fueron fortificadas con una cantidad conocida de PAHs. Con esto, se inició la validación de un método alternativo, el cual fue analizado con cromatógrafo de gases acoplado a un detector de masas (GC-‐MS).Ítem Effect of pyrolysis temperature on copper aqueous removal capability of biochar derived from the kelp macrocystis pyrifera(MDPI, 2021-10) Araya, Matías; Rivas, Jorge; Sepúlveda, Graciela; Espinoza-González, Camila; Lira, Sebastián; Meynard, Andrés; Blanco, Elodie; Escalona, Néstor; Ginocchio, Rosanna; Garrido-Ramírez, Elizabeth; Contreras-Porcia, LorettoSeaweed biochar is an efficient alternative bioadsorbent for Cu2+ removal due to its low cost and heavy metal removal capacity. Using the slow pyrolysis process, we produced biochars from Macrocystis pyrifera at 300 (BC300), 450 (BC450), and 600◦C (BC600). The physicochemical and structural properties of the biochar samples improved with increasing pyrolysis temperature from 300 to 450◦C, whereas no significant differences were observed with further increases in temperature to 600◦C. The yield ranged between 49% and 62% and had a high ash content (57.5–71.1%). BC450 and BC600 presented the highest surface areas and higher porosities. The FTIR spectra indicated that an increase of temperature decreased the acidic functional groups due to depolymerization and the dehydration processes, increasing the aromatic structures and the presence of calcium carbonate. The fittings of the kinetic models were different for the BCs: for the BC450 and BC600 samples, the Cu2+ adsorption was well-represented by a pseudo-first-order model; for BC300, a better fit was obtained with the pseudo-second-order model. The rate-limiting step of Cu2+ adsorption on BCs was represented by both models, liquid film diffusion and intraparticle diffusion, with surface diffusion being more important in BC300 and BC600, and intraparticle diffusion in BC450, in agreement with the pore size of the biochar samples. The adsorption isotherms of all BCs showed Langmuir behavior, representative of a chemisorption process, which was corroborated by the energy adsorption values determined by the D–R model. The maximum monolayer Cu2+ adsorption capacities were 93.55 and 58.0 mg g−1 for BC600 and BC450, respectively, whereas BC450 presented the highest affinity. Other mechanisms involved in controlling heavy metal removal from aqueous suspensions using these seaweed biochars remain to be explored. We conclude that BC450 and BC600 from M. pyrifera are the most efficient adsorbents for Cu2+ aqueous removal and are thus an appropriate alternative for bioremediation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Ítem Heavy Metal Depuration Steps for Gracilaria chilensis in Outdoor Culture Systems(MDPI, 2022-10) Rivas, Jorge; Piña, Florentina; Araya, Matías; Latorre-Padilla, Nicolás; Pinilla-Rojas, Benjamín; Caroca, Sofía; Bronfman, Francisca C.; Contreras-Porcia, LorettoSeaweed aquaculture is affected by natural and anthropogenic stressors, which put the biomass productivity of the cultures at risk. Seaweed biomass for commercial purposes, principally in pharmaceutical and/or nutraceutical applications, needs to be free of pollutants; therefore, controlled cultures have relevance in regulating the quality of biomass. The aim of this work was to demonstrate the successful utilization of controlled outdoor cultures to remove excess heavy metal accumulation in Gracilaria chilensis, an important commercial seaweed farming model. Specifically, we designed a simple and operational heavy metal depuration protocol, utilizing seawater and tap water removal, which permitted the concentration reduction of 10 heavy metals, including As, Cu, and Cd but not Zn, from the biomass at 7 days of culture. The percentage of depuration of the heavy metals ranged from 32 to 92% at 7 days, which was maintained throughout 21 days of culture. During the culture period, the monitored physicochemical parameters (temperature, salinity, and dissolved oxygen, among others) remained stable, with an increase in the daily growth rate (DGR% d−1) of the biomass recorded after 14 days of culture. Consequently, the experimental setup was successful for heavy metal depuration, which highlights the importance of controlled outdoor cultures as important tools of sustainability. © 2022 by the authors.Ítem Indoor and Outdoor Cultures of Gracilaria chilensis: Determination of Biomass Growth and Molecular Markers for Biomass Quality Evaluation(MDPI, 2023-03) Caroca-Valencia, Sofía; Rivas, Jorge; Araya, Matías; Núñez, Alejandra; Piña, Florentina; Toro-Mellado, Fernanda; Contreras-Porcia, LorettoTaking into consideration climate change scenarios, marine contamination, and a constantly expanding world population, seaweed aquaculture has become an important option for the large-scale production of high-quality biomass. Due to existing biological knowledge of Gracilaria chilensis, several cultivation strategies have been established for obtaining diverse biomolecules (lipids, fatty acids, pigments, among others) with nutraceutical properties. In this research, indoor and outdoor cultivation methodologies were applied to generate high biomass of G. chilensis with positive quality for productive purposes, where the quality was determined according to the concentrations of lipoperoxides and phenolic compounds and the total antioxidant capacity (TAC). The results showed that G. chilensis cultures, which were fertilized for three weeks with Basfoliar® Aktiv (BF) at concentrations of 0.05–1% v/v, obtained high biomass (1–1.3 kg m–2) and DGR (0.35–4.66% d–1), low lipoperoxides (0.5–2.8 µmol g–1 DT), and high phenolic compounds (0.4–0.92 µ eq. GA g–1 FT) and TAC (5–7.5 nmol eq. TROLOX g–1 FT) as compared with other culture media. Lower stress was determined under indoor cultures, due to the operative control of diverse physicochemical stressor parameters (T°, light intensity, photoperiod, among others). Therefore, the cultures developed allow scaling the biomass in productive terms and are suitable for obtaining compounds of interest. © 2023 by the authors.Ítem Methylglyoxal metabolism in seaweeds during desiccation(Universidad de Valparaíso. Facultad de Ciencias del Mar, 2016) Fierro, Camila; López-Cristoffanini, Camilo; Latorre, Nicolás; Rivas, Jorge; Contreras-Porcia, LorettoIn primary producers, diverse stressors cause an over-production of methylglyoxal (MG), which is principally detoxified by glyoxalase I (GLO1) activity. A recent proteomic study found that GLO1 was up-regulated during natural desiccation in the red seaweed Pyropia orbicularis, which inhabits the upper intertidal rocky zone and compared to other species, is highly tolerant to air exposure. To better understand and determine differential responses to desiccation stress, this study evaluated MG concentration and GLO1 activity in two species with contrasted vertical distribution, P. orbicularis and Lessonia spicata (lower distribution). Results showed that P. orbicularis successfully scavenges MG via increased GLO1 activity during desiccation. In contrast, GLO1 activity in L. spicata did not increase during desiccation, resulting in MG overproduction. This study is the first to quantify MG and GLO1 levels in seaweeds during natural stress, and partly explain the mechanisms by which P. orbicularis is dominant in the upper rocky intertidal zone.Ítem Subcritical water extraction of essential oils and plant oils(Elsevier B.V., 2023-12) Díaz-Reinoso, Beatriz; Rivas, Sandra; Rivas, Jorge; Domínguez, HerminiaSubcritical water extraction is a green technology with interesting advantages in relation to the possibility of processing fresh raw materials to sustainably obtain natural valuable products. The potential of this technology for the aqueous extraction of lipophilic fractions from plant biomass is well known and has recently attracted renewed interest. This review presents an update of the advances on the extraction of two valuable types of lipophilic products, essential oils and vegetal lipids from various plant biomasses. It also emphasizes the effect of process variables as particle size, time, liquid to solid ratio, pressure and temperature as well as the operation tunability to select optimal conditions for different solutes. The optimal operation conditions play a key role to efficiently recover these natural products with potential applications in cosmetic, food, agricultural and pharmaceutical/medical industries. © 2023 The AuthorsÍtem Transfer of pollutants from macrocystis pyrifera to tetrapygus niger in a highly impacted coastal zone of chile(MDPI, 2021-10) Latorre‐padilla, Nicolás; Meynard, Andrés; Rivas, Jorge; Contreras‐porcia, LorettoPAHs and heavy metals are characteristic pollutants in urbanized coastal areas, especially those with industrial activity. Given this context and the ability of Macrocystis pyrifera to drift when detached and provide trophic subsidy in coastal systems, we analyzed the potential transfer of pollutants to the herbivore Tetrapygus niger, through diet, in an industrialized coastal zone in Central Chile (Caleta Horcón) and characterized the impacted zone using diverse polluted ecotoxicological indices. For this purpose, a culture experiment was conducted where M. pyrifera individuals from Algarrobo (control site) were cultivated in Caleta Horcón and then used as food for T. niger. The contents of both PAHs and heavy metal contents were subsequently determined in algal tissue and sea urchin gonads as well as in the seawater. The results show that algae cultivated in Caleta Horcón had higher concentrations of naphthalene (NAF) compared to those from a low industrial impact zone (Algarrobo) (2.5 and 1.8 mg kg−1, respectively). The concentrations of Cu, As, and Cd were higher in Caleta Horcón than in Algarrobo in both M. pyrifera and T. niger. For all metals, including Pb, higher concentrations were present in T. niger than in M. pyrifera (between 5 and 798 times higher). Additionally, as indicated by the toxicological indices MPI (0.00804) and PLI (10.89), Caleta Horcón is highly contaminated with metals compared to Algarrobo (0.0006 and 0.015, respectively). Finally, the bioconcentration factor (BCF) and trophic transfer factor (TTF) values were greater than one in most cases, with values in Caleta Horcón exceeding those in Algarrobo by one or two orders of magnitude. This study provides evidence that Caleta Horcón is a highly impacted zone (HIZ) compared to Algarrobo, in addition to evidence that the biomagnification of certain pollutants, including the possible responses to contaminants, are apparently not exclusively transferred to T. niger through diet. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.