Gating-induced large aqueous volumetric remodeling and aspartate tolerance in the voltage sensor domain of Shaker K+ channels

Indexación: Scopus.ACKNOWLEDGMENTS. We thank Chris Lingle and Yu Zhou (Washington University) for critical reading of the manuscript and Victoria Prado for Xenopus care and oocyte preparation. We also thank Millennium Scientific Initiative P029-022-F. This work was supported by Fondecyt Postdoctoral Grants 3170599 (to I.D.-F.) and 3160321 (to H.M.).Neurons encode electrical signals with critically tuned voltage-gated ion channels and enzymes. Dedicated voltage sensor domains (VSDs) in these membrane proteins activate coordinately with an unresolved structural change. Such change conveys the transmembrane translocation of four positively charged arginine side chains, the voltage-sensing residues (VSRs; R1–R4). Countercharges and lipid phosphohead groups likely stabilize these VSRs within the low-dielectric core of the protein. However, the role of hydration, a sign-independent charge stabilizer, remains unclear. We replaced all VSRs and their neighboring residues with negatively charged aspartates in a voltage-gated potassium channel. The ensuing mild functional effects indicate that hydration is also important in VSR stabilization. The voltage dependency of the VSR aspartate variants approached the expected arithmetic summation of charges at VSR positions, as if negative and positive side chains faced similar pathways. In contrast, aspartates introduced between R2 and R3 did not affect voltage dependence as if the side chains moved outside the electric field or together with it, undergoing a large displacement and volumetric remodeling. Accordingly, VSR performed osmotic work at both internal and external aqueous interfaces. Individual VSR contributions to volumetric works approached arithmetical additivity but were largely dissimilar. While R1 and R4 displaced small volumes, R2 and R3 volumetric works were massive and vectorially opposed, favoring large aqueous remodeling during VSD activation. These diverse volumetric works are, at least for R2 and R3, not compatible with VSR translocation across a unique stationary charge transfer center. Instead, VSRs may follow separated pathways across a fluctuating low-dielectric septum. © National Academy of Sciences. All rights reserved.https://www.pnas.org/content/115/32/820

Element specific characterization of heterogeneous magnetism in (Ga,Fe)N films

We employ x-ray spectroscopy to characterize the distribution and magnetism of particular alloy constituents in (Ga,Fe)N films grown by metal organic vapor phase epitaxy. Furthermore, photoelectron microscopy gives direct evidence for the aggregation of Fe ions, leading to the formation of Fe-rich nanoregions adjacent to the samples surface. A sizable x-ray magnetic circular dichroism (XMCD) signal at the Fe L-edges in remanence and at moderate magnetic fields at 300 K links the high temperature ferromagnetism with the Fe(3d) states. The XMCD response at the N K-edge highlights that the N(2p) states carry considerable spin polarization. We conclude that FeN{\delta} nanocrystals, with \delta > 0.25, stabilize the ferromagnetic response of the films.Comment: 4 pages, 3 figures, 1 tabl

Face recognition system using fringe projection and moiré: characterization with fractal parameters

We show a new method for face recognition which combines the projection of structures with different characteristics (fringes, bars or grids, dots or speckle) over the face. These projections will then allow the creation of a computer-generated moiré pattern over which different kinds of fractal and complex geometry parameters are then measured. Such parameters will then be used as inputs for a neuro-symbolic hybrid system. Here, we analyze the incidence of some parameters on the efficience for the face recognition method

Breeding structure of Drosophila buzzatii in relation to competition in prickly pears (Opuntia ficus-indica)

International audienc

Primary care healthcare policy impelmentation in the eastern Mediterranean region; experience of six countries: part ii

Background: Primary healthcare (PHC) is the cornerstone of health systems for the rightful access and cost-effective. It is a key factor in the global strategy for universal health coverage (UHC). Implementing PHC requires an understanding of health system under prevailing circumstances essential to implement PHC, but data are unavailable. Objectives: This paper describes and analyses the health systems of Algeria, Kuwait, Morocco, Saudi Arabia, Jordan and Iraq and PHC status. Methods: Data were collected during a Workshop at 2018 WONCA East Mediterranean Regional Conference in Kuwait. Academic family physicians (FP) and general practitioners (GP) presented their country reports using the WONCA framework of 11 PowerPoint slides. WHO EMRO reflected on how countries’ experiences can contribute to their Frameworks on Integrated People-Centered Health Services and UHC.. Results: The six countries had achieved a great improvement in populations’ health, but currently face challenges of health financing, small number of certified family physicians, difficulties to access service and bureaucratic process. Main concerns were the absence of a family practice model, brain drain and immigration of FPs. Countries differed in building a coherent policy. Conclusion: Priorities should be focused on: developing PHC model in Eastern Mediterranean Region with advocacy for community-based PHC to policymakers: capacity building for strengthening PHC-oriented health systems with FP specialty training and restrict practicing to fully trained FPs; engage communities to improve understanding of PHC; adopt quality and accreditation policies for better services; validation of the referral and follow-up process; and, develop public-private partnership mechanisms to enhance PHC for UHC

Agricultural eco-efficiency and water footprint- A case study of fifteen crops in the Chupaca province of Peru

The water footprint is an indicator of the impact of water use from its formation to its final destination. Agricultural eco-efficiency measures the efficient use of resources or materials available for crop production. Water's economic productivity analyses a product's efficient value as per its water supply and commercial value. The present research aimed to determine and relate the water footprint, economic productivity of water and agricultural eco-efficiency of 15 crops in the province of Chupaca - Peru. Georeferencing material was used for the delimitation of agricultural species, CROPWAT 8.0, CLIMWAT8.0, ArcGis 10.5 software, mathematical equations for the water footprint, agricultural eco-efficiency (Data Envelopment Analysis (DEA)) and economic productivity of water. The Total water footprint (TWF) of the fifteen crops was 1718237.01 m3/ton, likewise the BlueWF > GreenWF > GreyWF. In their economic outputs, gross value of production (GVP) > agricultural production (Ag-p) > economic rent agricultural (ERA) was verified. In environmental costs, water consumption that meets the needs of crops (Wc-Ag) > consumption of phytosanitary products (C-fly) > fertilizer consumption (C-fe) was determined. The average Agricultural eco-efficiency (Ag-Eec) and Economic water productivity (Ewp) were 89.8% and 0.046 PEN/m3 respectively. Statistical analysis between Ewp and Ag-Eec was rho = 0.18, t-test = 0.66 < 2.16 (α = 0.05; bilateral), and the correlation indicated that both activities are independent. The environmental costs and economic outputs of agricultural eco-efficiency did not influence the economic value of water.

Analyzing solid waste landfills using satellite imagery and designing new landfill reception areas

Solid waste disposal is important for environmental management for good quality of life in urban cities. Among them is the final disposal of waste in landfills. Landfills can receive tons of waste, but they must be far away from natural resources and urban areas. The research aimed to analyze the physical and biological conditions and design a geolocation map of new sanitary landfills in three urban cities in Peru (Chilca, El Tambo and Huancayo). Landsat 8 OLI/TIRS satellite imagery was used to analyze the physical (LST and Methane) and biological (NDVI and SAVI) conditions of the landfills. The geolocation of the landfills was analyzed through the relationship, intersection and discrimination between their surface criteria (soil type, current use, geology and physiography) and climatic factors (temperature, humidity and precipitation). The physical and biological conditions of the landfills were: CH4: Chilca 8.33g > Huancayo 4.76g > El-Tambo 3.17g; SAVI: Chilca 0.61 > El Tambo 0.54 > Huancayo 0.51; LST: Huancayo 26.15°C > Chilca 24.03°C > El Tambo 22.75°C; NDVI: Chilca 0.85 > Huancayo 0.81 > El Tambo 0.8. In the three cities, "natural grasslands" were considered suitable land for the new solid waste landfill site. The multiple relationship, intersection, and discrimination of surface criteria and climatic factors were categorized into five types of sustainable geolocation (very appropriate > appropriate > moderately adequate > less appropriate > inappropriate) for new solid waste landfills. It was very important to discount the influence areas (rivers and lagoons) to avoid damaging the natural resources.      

Fructose-1,6-bisphosphate couples glycolytic flux to activation of Ras

Yeast and cancer cells share the unusual characteristic of favoring fermentation of sugar over respiration. We now reveal an evolutionary conserved mechanism linking fermentation to activation of Ras, a major regulator of cell proliferation in yeast and mammalian cells, and prime proto-oncogene product. A yeast mutant (tps1Δ) with overactive influx of glucose into glycolysis and hyperaccumulation of Fru1,6bisP, shows hyperactivation of Ras, which causes its glucose growth defect by triggering apoptosis. Fru1,6bisP is a potent activator of Ras in permeabilized yeast cells, likely acting through Cdc25. As in yeast, glucose triggers activation of Ras and its downstream targets MEK and ERK in mammalian cells. Biolayer interferometry measurements show that physiological concentrations of Fru1,6bisP stimulate dissociation of the pure Sos1/H-Ras complex. Thermal shift assay confirms direct binding to Sos1, the mammalian ortholog of Cdc25. Our results suggest that the Warburg effect creates a vicious cycle through Fru1,6bisP activation of Ras, by which enhanced fermentation stimulates oncogenic potency. © 2017 The Author(s)