Aquaporin Gating: A New Twist to Unravel Permeation through Water Channels

Aquaporins (AQPs) are small transmembrane tetrameric proteins that facilitate water, solute and gas exchange. Their presence has been extensively reported in the biological membranes of almost all living organisms. Although their discovery is much more recent than ion transport systems, different biophysical approaches have contributed to confirm that permeation through each monomer is consistent with closed and open states, introducing the term gating mechanism into the field. The study of AQPs in their native membrane or overexpressed in heterologous systems have experimentally demonstrated that water membrane permeability can be reversibly modified in response to specific modulators. For some regulation mechanisms, such as pH changes, evidence for gating is also supported by high-resolution structures of the water channel in different configurations as well as molecular dynamics simulation. Both experimental and simulation approaches sustain that the rearrangement of conserved residues contributes to occlude the cavity of the channel restricting water permeation. Interestingly, specific charged and conserved residues are present in the environment of the pore and, thus, the tetrameric structure can be subjected to alter the positions of these charges to sustain gating. Thus, is it possible to explore whether the displacement of these charges (gating current) leads to conformational changes? To our knowledge, this question has not yet been addressed at all. In this review, we intend to analyze the suitability of this proposal for the first time.Fil: Ozu, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Alvear Arias, Juan José. Universidad de Valparaíso; ChileFil: Fernandez, Miguel. Universidad de Valparaíso; ChileFil: Caviglia, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Peña Pichicoi, Antonio. Universidad de Valparaíso; ChileFil: Carrillo, Christian. Universidad de Valparaíso; ChileFil: Carmona, Emerson. No especifíca;Fil: Otero Gonzalez, Anselmo. Universidad de La Habana; CubaFil: Garate, José Antonio. Universidad de Valparaíso; ChileFil: Amodeo, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Gonzalez, Carlos. Universidad de Valparaíso; Chil

Potential and impacts of cogeneration in tropical climate countries: Ecuador as a case study

La gran dependencia de los combustibles fósiles, baja eficiencia energética, escasa diversificación de la energía y una baja tasa de acceso a la electricidad son desafíos que deben resolverse en muchos países en desarrollo para hacer sus sistemas energéticos más sostenibles. La cogeneración ha sido identificada como una estrategia clave para aumentar la capacidad de generación de energía, reducir las emisiones de gases de efecto invernadero (GEI), y mejorar la eficiencia energética en la industria, uno de los sectores más demandantes de energía en todo el mundo. Sin embargo, son necesarios más estudios para definir enfoques para implementar la cogeneración, particularmente en países con climas tropicales (como Ecuador). En Ecuador, el Plan Nacional de Eficiencia Energética incluye la cogeneración como una de las cuatro vías para hacer más sostenible el uso de la energía en la industria. El objetivo de este trabajo es doble: (1) identificar el potencial de cogeneración en la Industria ecuatoriana, y (2) mostrar los impactos positivos de la cogeneración en la capacidad de generación de energía, reducción de emisiones de GEI, eficiencia energética y economía del país.High dependency on fossil fuels, low energy e ciency, poor diversification of energy sources, and a low rate of access to electricity are challenges that need to be solved in many developing countries to make their energy systems more sustainable. Cogeneration has been identified as a key strategy for increasing energy generation capacity, reducing greenhouse gas (GHG) emissions, and improving energy e ciency in industry, one of the most energy-demanding sectors worldwide.However, more studies are necessary to define approaches for implementing cogeneration, particularly in countries with tropical climates (such as Ecuador). In Ecuador, the National Plan of Energy E ciency includes cogeneration as one of the four routes for making energy use more sustainable in the industrial sector. The objective of this paper is two-fold: (1) to identify the potential of cogeneration in the Ecuadorian industry, and (2) to show the positive impacts of cogeneration on power generation capacity, GHG emissions reduction, energy e ciency, and the economy of the country. The study uses methodologies from works in specific types of industrial processes and puts them together to evaluate the potential and analyze the impacts of cogeneration at national level. The potential of cogeneration in Ecuador is ~600 MWel, which is 12% of Ecuador’s electricity generation capacity. This potential could save ~18.6 106 L/month of oil-derived fuels, avoiding up to 576,800 tCO2/year, and creating around 2600 direct jobs. Cogeneration could increase energy e ciency in the Ecuadorian industry by up to 40%

Revista Temas Agrarios Volumen 26; Suplemento 1 de 2021

1st International and 2nd National Symposium of Agronomic Sciences: The rebirth of the scientific discussion space for the Colombian Agro.1 Simposio Intenacional y 2 Nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano