Structural and functional effects of natural phenolic compounds on rhodopsin mutants associated with retinitis pigmentosa

Dietary polyphenols represent a group of secondary metabolites which widely occur in fruits, vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products. Previous studies have shown the interaction of certain phenolic compounds with estrogen and adenosine receptors, belonging to the G-protein coupled receptors (GPCRs) superfamily. GPCRs are the largest family of signal transduction molecules involved in most of the physiological processes. Rhodopsin is the prototypic member of GPCRs. This receptor is the major protein found in the disks membrane of the outer segments of retinal rod photoreceptor cells and the first with resolved crystal structure. Mutations in rhodopsin are associated with retinitis pigmentosa (RP), a group of inherited visual diseases causing retinal degeneration due to progressive loss of rod and cone photoreceptors cells and leading to blindness. Several studies have been carried out on rhodopsin RP mutants in order to elucidate the molecular mechanism of the disease. This is the first step before suitable therapeutic approaches can be developed. Some of the proposed treatments are based on pharmacological rescue, in which small molecules known as chemical or pharmacological chaperones bind and stabilize misfolded opsins. Polyphenols have been proposed as useful agents against retinal toxicity but no clear evidence of these compounds at the molecular level of the visual phototransduction System has been presented so far. Given the interest in finding new ligands to compensate the deleterious effects of RP mutations, the aim of this thesis was to evaluate the effect of the polyphenols on the structure and function of the visual pigment rhodopsin RP mutants and to study their preferences to bind to rhodopsin. Herein we found that polyphenols quercetin (Q), resveratrol (R) and epigallocatechin gallate decreased the expression of wild-type and mutant rhodopsins when added to eukaryotic cell cultures. However, no differences were observed in the biophysical and functional properties of immunopurified pigments regenerated with 11-cis-retinal chromophore treated with O and R al concentrations of 1 µM and 10 µM Our molecular docking complementary analysis indicated that the polyphenol compounds studied can bind to rhodopsin and could act as allosteric ligands for rhodopsin regenerated with 9-cis-retinal as a chromophore. Our results showed that Q improved the percentage and rate of regeneration of opsin with 9-cis-retinal when compared to 11-cis-retinal. Q enhances the structural compaction around the Schiff Base linkage between the retinal chromophore and opsin, preventing the chemical retinal trapping reagent hydroxylamine from easily entering in the retinal pocket. Moreover, functional experiments on wild-type and G90V mutant rhodopsin regenerated with 9-cis-retinal in presence of 1 µM Q, showed a sigmoidal kinetics clearly representative of cooperative binding. Furthermore, the presence of Q bound to rhodopsin was demonstrated by HPCL-MS analysis. In summary, it has been shown, by using complementary molecular biology and analytical methods and in silico computational studies that some polyphenol compounds, and particularly quercetin, can act as allosteric modulators of 9-cis-rhodopsin. This effect is particularly significant in the case of the G90V mutation associated with the retinal degenerative disease RP, where the deleterious properties of the mutation could be partially compensated, and opens novel possibility of using such compounds in the treatment of visual neurodegeneration such as that associated to RP.Los polifenoles de la dieta representan, un grupo de metabolitos secundarios los cuales se encuentra ampliamente en frutas y vegetales, vino, te, aceite de oliva extra virgen, chocolate y otros productos de cacao. Estudios previos han mostrado la interacción de algunos compuestos fenólicos con receptores de estrógeno y adenosina, pertenecientes a la superfamilia de receptores acoplados a proteína G (GPCRs). Estos GPCRs son la familia más grande de moléculas de transducción de señales involucradas en la mayoría de procesos fisiológicos. Rodopsina es el miembro prototípico de GPCRs y es la proteína mayoritaria encontrada en la membrana de los discos del segmento exterior de los bastones, células fotoreceptoras de la retina, y el primer con la estructura cristalina resuelta. Mutaciones en rodopsina se han asociado con retinosis pigmentaria (RP), un grupo de enfermedades visuales hereditarias que causan degeneración retiniana la cual lleva a la pérdida progresiva de las células fotoreceptoras, bastones y conos. Causando ceguera. Numerosos estudios sobre mutantes de RP se han llevado a cabo con la finalidad de elucidar los mecanismos moleculares de la enfermedad como un primer paso necesario antes de que se puedan desarrollar enfoques terapéuticos adecuados. Algunos de los tratamientos propuestos se basan en el rescate farmacológico, en el cual moléculas pequeñas conocidas como chaperonas químicas o farmacológicas se unen y estabilizan opsinas mal plegadas. Los polifenoles se han propuesto como agentes útiles contra la toxicidad retiniana, pero hasta ahora no se ha presentado evidencia clara de los efectos de estos compuestos a nivel molecular del sistema de fototransducción visual. Dado el interés en encontrar nuevos ligandos que puedan compensar los efectos causados por mutaciones de RP, el objetivo de esta tesis fue evaluar el efecto de los polifenoles sobre la estructura y función la rodopsina y mutantes de RP G90V, Y102H e 1307N y estudiar las preferencias de unión a rodopsina Se encontró al adicionar quercetina (Q), resveratrol (R) y epigalocatequin galato en células eucariotas, éstos afectan la expresión de la rodopsina nativa y de mutantes estudiados. Por otro lado, no se observaron diferencias en las propiedades biofísicas y funcionales de los pigmentos inmunopurificados regenerados con el cromofóro 11-cis retinal tratados con Q y R a concentraciones de 1 µM y 10 µM. Nuestro análisis complementario de acoplamiento molecular indicaron que los compuestos fenólicos estudiados aquí pueden unirse a rodopsina y podrían actuar como ligandos alostéricos para rodopsina unidos al cromóforo 9-cis-retinal. Analizando los resultados de las propiedades espectrales y bioquímicas de rodopsinas expresadas heterólogamente en cultivos celulares mostraron que Q mejoró el porcentaje y velocidad de regeneración de la opsina regenerada con 9-cis-retinal al compararla con 11-cis retinal. Se encontró que la Q mejora la compactación estructural al entorno de la base de Schiff de unión de la opsina y el cromóforo, evitando que el reactivo hidroxilamina entre fácilmente en el sitio de unión del retinal. Los experimentos funcionales de las muestras tratadas con 1 µM Q para la rodopsina nativa y mutante G90V regenerados con 9-cis-retinal mostraron una cinética sigmoidal claramente representativa de una coperatividad de unión. Además, la presencia de Q en la muestra final después de la inmunopurificación se demostró mediante HPLC-MS. Se ha demostrado mediante el uso de técnicas de biología molecular, métodos analíticos y en estudios computacionales, que algunos compuestos fenólicos, en particular la Q, pueden actuar como moduladores alostéricos de la 9-cis-rodopsina, efecto significativo en el caso del mutante G90V asociado a RP, donde las propiedades deletéreas de la mutación podrían ser parcialmente compensadas, y abre una nueva posibilidad de utilizar dichos compuestos en el tratamiento de neurodegeneraciones visual asociados a RP

Flavonoid allosteric modulation of mutated visual rhodopsin associated with retinitis pigmentosa

Dietary flavonoids exhibit many biologically-relevant functions and can potentially have beneficial effects in the treatment of pathological conditions. In spite of its well known antioxidant properties, scarce structural information is available on the interaction of flavonoids with membrane receptors. Advances in the structural biology of a specific class of membrane receptors, the G protein-coupled receptors, have significantly increased our understanding of drug action and paved the way for developing improved therapeutic approaches. We have analyzed the effect of the flavonoid quercetin on the conformation, stability and function of the G protein-coupled receptor rhodopsin, and the G90V mutant associated with the retinal degenerative disease retinitis pigmentosa. By using a combination of experimental and computational methods, we suggest that quercetin can act as an allosteric modulator of opsin regenerated with 9-cis-retinal and more importantly, that this binding has a positive effect on the stability and conformational properties of the G90V mutant associated with retinitis pigmentosa. These results open new possibilities to use quercetin and other flavonoids, in combination with specific retinoids like 9-cis-retinal, for the treatment of retinal degeneration associated with retinitis pigmentosa. Moreover, the use of flavonoids as allosteric modulators may also be applicable to other members of the G protein-coupled receptors superfamily.Peer ReviewedPostprint (author's final draft

Polyphenolic Profile and Antioxidant Activity of Leaf Purified Hydroalcoholic Extracts from Seven Mexican Persea americana Cultivars

Persea americana (avocado) is a fruit consumed worldwide; however, since avocado leaves are apparently a natural ingredient that can be used as a traditional medicine, they can be a potential source of bioactive compounds. This study aimed to analyze the antioxidant activity of seven Mexican avocado leaf extracts by DPPH•, ABTS•+, and lipid peroxidation (LPO), and to identify the compoundprofilebyliquidchromatographycoupledtomassspectrometry/electronsprayionization. The highest free radical-scavenging activity was observed for Platano Delgado and Criollo 6 avocado cultivars havin IC50 values of 271.86 ± 13.69 and 269.56 ± 6.53 for DPPH• and ABTS•+ radicals, respectively, while the best result for lipid oxidation inhibition was registered in Criollo 6 cultivar extract. Inthisstudyfortyonecompoundsweredetectedinavocadoleavesofthethesevencultivars analyzed, and of these compounds, eighteen phenolics were identified for first time in such plant material. The present study demonstrated that Mexican cultivars of Persea americana possess diverse polyphenolic compounds with strong antioxidant activity, which might be useful in the food and pharmaceutical industries

Valores Éticos-Profesionales en la Formación del Licenciado en Nutrición de una Universidad del Estado de Zacatecas

A current challenge in higher education in Mexico is to build educational projects that respond to the needs of society, in addition to training professional profiles that are competent, ethical, and act based on values and are socially committed. Objective: Evaluate the professional ethical values in the training of the graduate in Nutrition. Materials and methods: A quantitative-qualitative, observational, descriptive and cross-sectional study was carried out, an accidental non-probabilistic sampling was applied, obtaining the total results of 56 students enrolled in the 8th semester to whom a questionnaire was applied on professional ethical values in the formation of the Graduate in Nutrition. For data processing, the software SPSS 25 and QDA Miner lite 2.0.9 were used. Results. The values that students associate with their future professional work are respect, honesty, responsibility and empathy, however less than a third of the participants know the values proposed by the academic program of the degree in nutrition, a significant number of students can formulate the concept of value, however they do not correctly relate them to the values proposed by the Code of Professional Ethics of the Nutrition Graduate with some of its articles.Un reto presente en la educación superior en México es el de construir proyectos educativos que respondan a necesidades de la sociedad además de formar perfiles profesionales que sean competentes, éticos y con un actuar en valores y socialmente comprometidos. Objetivo: Evaluar los valores éticos profesionales en la formación del licenciado en Nutrición. Materiales y métodos: Se realizó un estudio cuanti-cualitativo, observacional, descriptivo y transversal, se aplicó un muestreo no probabilístico accidental, obteniendo los resultados totales de 56 alumnos inscritos al 8vo semestre a los cuales se les aplico un cuestionario sobre valores ético profesionales en la formación del Licenciado en Nutrición. Para el procesamiento de los datos se utilizó los software SPSS 25 y QDA Miner lite 2.0.9. Resultados. Los valores que los alumnos relacionan con su futuro quehacer profesional son el respeto, la honestidad, la responsabilidad y la empatía, sin embargo menos de un tercio de los participantes conocen los valores que propone el programa académico de la licenciatura en nutrición, un número importante de alumnos puede formular el concepto de valor, no obstante no los relacionan correctamente  con los valores que propone el Código de ética profesional del licenciado en nutrición con algunos de sus artículos

¿Por qué y para qué estudiar Biología? Percepción de estudiantes universitarios

El objetivo del trabajo fue explorar las apreciaciones de estudiantes de la Facultad de Estudios Superiores Iztacala, UNAM, sobre cursar la carrera de Biología. Para ello se aplicó una encuesta de dos preguntas, ¿Por qué estudiar la carrera de biología? y ¿Para qué estudiar biología?, a 72 estudiantes (19-20 años) de dicha carrera. Las respuestas se clasificaron en cuatro categorías y diversas subcategorías para después obtener la frecuencia. En las respuestas de por qué estudiar biología, el conocimiento e investigación tuvo una frecuencia de 68, seguida por la vocación profesional (58) y por ser una carrera multidisciplinaria (37). En relación al para que estudiar biología, la formación disciplinar tuvo la mayor frecuencia (98), seguida por la profesionalización (9). Por lo que concluimos que los estudiantes eligen biología por interés en el conocimiento e investigación científica y para alcanzar una formación disciplinar y resolver problemas.The objective of the work was to explore the appreciation of students of the Iztacala UNAM, about studying the Biology career. For this, a survey of two questions was applied: Why study the biology degree? and Why study biology ?, to 72 students (19-20 years) of that career. The answers were classified into four categories and various subcategories to later obtain the frequency. In the answers to why study biology, the knowledge and research had a frequency of 68, followed by professional vocation (58) and for being a multidisciplinary career (37). In relation to the fact that to study biology, the disciplinary training had the highest frequency (98), followed by professionalization (9). We conclude that students choose biology for interest in scientific knowledge and research and to achieve a disciplinary training and salve problems

Medición de subsidencia del terreno causada por sobreexplotación de acuíferos mediante herramientas GEP: A-DInSAR en la nube

[EN] Groundwater is a vitally important resource for humans. One of the main problems derived from the overexploitation of aquifers is land subsidence, which in turn carries other associated natural risks. Advanced Differential satellite radar interferometry (A-DInSAR) techniques provide valuable information on the surface displacements of the ground, which serve to characterize both the deformational behaviour of the aquifer and its properties. RESERVOIR is a research project belonging to the European PRIMA programme, whose main objective is to design sustainable groundwater management models through the study of four areas of the Mediterranean subjected to water stress. One of the main tasks of the project is the integration of the terrain deformation data obtained with satellite remote sensing techniques in the hydrogeological and geomechanical models of the aquifers. In the present work, a first evaluation of the deformation of the ground in each study area is carried out using the tools contained in the Geohazards Exploitation Platform (GEP). This is a service financed by the European Space Agency (ESA) that allows processing directly on its server, without need to store data or applications locally.[ES] Las aguas subterráneas son un recurso de vital importancia para el ser humano. Una de las principales problemáticas derivadas de la sobreexplotación de acuíferos es la subsidencia del terreno, que a su vez lleva asociados otros riesgos naturales. Las técnicas avanzadas de interferometría radar diferencial de satélite (A-DInSAR) aportan información muy valiosa sobre los desplazamientos superficiales del terreno, que sirven para caracterizar tanto el comportamiento geomecánico del acuífero como sus propiedades. RESERVOIR es un proyecto de investigación perteneciente al programa europeo PRIMA, cuyo principal objetivo es diseñar modelos sostenibles de gestión de aguas subterráneas mediante el estudio de cuatro zonas del Mediterráneo sometidas a estrés hídrico. Una de las principales tareas del proyecto es la integración de los datos de deformación del terreno obtenidos con técnicas de teledetección por satélite en los modelos hidrogeológicos y geomecánicos de los acuíferos. En el presente trabajo se realiza una primera evaluación de la deformación del terreno en cada zona de estudio utilizando las herramientas contenidas en la Geohazards Exploitation Platform (GEP). Este servicio financiado por la Agencia Espacial Europea (ESA) permite realizar procesados directamente en su servidor, sin necesidad de almacenar datos ni aplicaciones en local.This work was supported by RESERVOIR project, which is part of the PRIMA Programme supported under Horizon 2020 the European Union's Framework Programme for Research and Innovation. Grant Agreement number: [1924] [RESERVOIR] [Call 2019 Section 1 Water RIA]. Copernicus Sentinel-1 IW SAR data were provided and processed in ESA’s Geohazards Exploitation Platform (GEP), in the framework of the GEP Early Adopters Programme.Bru, G.; Ezquerro, P.; Guardiola-Albert, C.; Béjar-Pizarro, M.; Herrera, G.; Tomás, R.; Navarro-Hernández, M.... (2021). Land subsidence analysis caused by aquifer overexploitation using GEP tools: A-DInSAR on the cloud. En Proceedings 3rd Congress in Geomatics Engineering. Editorial Universitat Politècnica de València. 127-136. https://doi.org/10.4995/CiGeo2021.2021.12722OCS12713

Milking to 2030: economic and sustainability prospective of the Mexican dairy sector

Objective: This study aims to assess the productive and economic performance of the Mexican milk sector, particularly focusing on small and medium-scale dairy farms, and examining pessimistic, base, and optimistic scenarios. Design/methodology/approach: Employing a statistical univariate method with time series analysis (ARIMA), we analyzed productive efficiency and price behavior in Mexican dairy systems. Deterministic and stochastic estimations for production volume, milk price, and cattle inventory from 2021 to 2030 were established using confidence intervals to construct pessimistic (lower interval), base (mean), and optimistic (upper interval) scenarios. Results: The evaluated period witnessed an estimated 10.27% increase in production, equivalent to 576 million liters of milk, with an average annual growth rate of 1.0922%. Milk prices displayed an upward trend, with average prices of $0.66,$0.69, and $0.72 under pessimistic, base, and optimistic scenarios, respectively. In 2030, a 22$0.45 USD per liter in 2030, costs under pessimistic, base, and optimistic scenarios were $1,658.21,$1,756.43, and $1,855.31, resulting in profits of$1,160.75, $1,229.50, and$1,022.45 from milk sales. Cattle inventory exhibited an upward trend, paralleling milk volumes and prices. Limitations on study/implications: The study's use of a univariate method may incompletely capture market dynamics complexity, potentially underestimating the impact of external market forces and global economic conditions on milk prices. Findings/conclusions: To secure forecasted milk volumes in base and optimistic scenarios, maintaining and enhancing good management practices is crucial. Additionally, addressing the imperative to augment production efficiency and improve environmental sustainability and animal welfare is essential.Objective: This study aims to assess the productive and economic performance of the Mexican milk sector, particularly focusing on small and medium-scale dairy farms, and examining pessimistic, base, and optimistic scenarios. Design/methodology/approach: Employing a statistical univariate method with time series analysis (ARIMA), we analyzed productive efficiency and price behavior in Mexican dairy systems. Deterministic and stochastic estimations for production volume, milk price, and cattle inventory from 2021 to 2030 were established using confidence intervals to construct pessimistic (lower interval), base (mean), and optimistic (upper interval) scenarios. Results: The evaluated period witnessed an estimated 10.27% increase in production, equivalent to 576 million liters of milk, with an average annual growth rate of 1.0922%. Milk prices displayed an upward trend, with average prices of $0.66,$0.69, and $0.72 under pessimistic, base, and optimistic scenarios, respectively. In 2030, a 22$0.45 USD per liter in 2030, costs under pessimistic, base, and optimistic scenarios were $1,658.21,$1,756.43, and $1,855.31, resulting in profits of$1,160.75, $1,229.50, and$1,022.45 from milk sales. Cattle inventory exhibited an upward trend, paralleling milk volumes and prices. Limitations on study/implications: The study's use of a univariate method may incompletely capture market dynamics complexity, potentially underestimating the impact of external market forces and global economic conditions on milk prices. Findings/conclusions: To secure forecasted milk volumes in base and optimistic scenarios, maintaining and enhancing good management practices is crucial. Additionally, addressing the imperative to augment production efficiency and improve environmental sustainability and animal welfare is essential

Miradas contemporáneas de los pueblos originarios en México

Este libro resume una amplia discusión sobre el papel que tienen los grupos originarios en México y la condición de las etnias a lo largo del territorio nacional. Desde hace cientos de años los pueblos indígenas y afrodescendientes han sido excluidos del desarrollo central de México, y en mayor o menor medida, estos grupos han ocupado un lugar residual en las políticas públicas de los diferentes gobiernos, y sufrido de manera regular la discriminación por parte del resto de la población.CEDIPIEM, UAEMéx, BUAP, Center for Earth Ethic

Spatial distribution of nitrate health risk associated with groundwater use as drinking water in Merida, Mexico

Water containing nitrate levels above 45 mg/l is not recommended for human consumption and its prolonged intake is associated with various health conditions. In Merida city, Mexico, the only source for water supply is a karstic aquifer, but the absence of sewerage and drainage networks makes it highly vulnerable to anthropogenic contamination. In this work, the concentration and spatial distribution of nitrate in the Merida’s karstic aquifer were assessed by statistical and geostatistical techniques. The sources of nitrate contamination were tracked by making statistical correlations between nitrate concentrations and key ions; the potential risk to human health was also estimated by using the Hazard Index (HI). A total of 177 groundwater samples were collected from the four water supply systems serving Merida, during 2012 and 2013. Nitrate concentrations from collected samples varied between 15.51 and 70.61 mg/l, with maximum and minimum concentrations per sampling point ranging from 47.47 to 70.61 mg/l and from 15.51 to17.32 mg/l, respectively. Significant positive correlations (P < 0.05) between nitrates and chlorides, sulphates and potassium were found, which may indicate potential contamination from domestic wastewater and agricultural activities. The spatial distribution of nitrate concentrations in the aquifer revealed an increase in nitrates following a trajectory South – North West, towards central and northwestern zones within Merida Metropolitan Area. From the health risk analysis, it was found that infants exposed at current nitrate levels are at a higher risk (HIMAX = 1.40) than adults (HR<1.0) and therefore, there is a clear need for implementing effective strategies to protect groundwater quality and to better manage and control nitrate pollution sources