Las cuevas turísticas de Castilla y León como recurso docente en geología

Esta propuesta docente didáctica para la materia de Geología, está centrada en el alumnado de 2º de Bachillerato (aunque podría utilizarse para cualquiera de los cursos en los cuales se imparte geología, tanto en la ESO como en el bachillerato) y tiene como fin favorecer el aprendizaje, por parte de los alumnos, de los contenidos correspondientes al modelado kárstico mediante visitas al interior de las cuevas kársticas presentes en Castilla y León, de acceso sencillo y visitables turísticamente.Departamento de Física de la Materia Condensada, Cristalografía y MineralogíaMáster en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanzas de Idioma

Leptin counteracts the hypoxia-induced inhibition of spontaneously firing hippocampal neurons: a microelectrode array study.

Besides regulating energy balance and reducing body-weight, the adipokine leptin has been recently shown to be neuroprotective and antiapoptotic by promoting neuronal survival after excitotoxic and oxidative insults. Here, we investigated the firing properties of mouse hippocampal neurons and the effects of leptin pretreatment on hypoxic damage (2 hours, 3% O(2)). Experiments were carried out by means of the microelectrode array (MEA) technology, monitoring hippocampal neurons activity from 11 to 18 days in vitro (DIV). Under normoxic conditions, hippocampal neurons were spontaneously firing, either with prevailing isolated and randomly distributed spikes (11 DIV), or with patterns characterized by synchronized bursts (18 DIV). Exposure to hypoxia severely impaired the spontaneous activity of hippocampal neurons, reducing their firing frequency by 54% and 69%, at 11 and 18 DIV respectively, and synchronized their firing activity. Pretreatment with 50 nM leptin reduced the firing frequency of normoxic neurons and contrasted the hypoxia-induced depressive action, either by limiting the firing frequency reduction (at both ages) or by increasing it to 126% (in younger neurons). In order to find out whether leptin exerts its effect by activating large conductance Ca(2+)-activated K(+) channels (BK), as shown on rat hippocampal neurons, we applied the BK channel blocker paxilline (1 µM). Our data show that paxilline reversed the effects of leptin, both on normoxic and hypoxic neurons, suggesting that the adipokine counteracts hypoxia through BK channels activation in mouse hippocampal neurons

Measuring Ca2 + inside intracellular organelles with luminescent and fluorescent aequorin-based sensors

Producción CientíficaGFP-Aequorin Protein (GAP) can be used to measure [Ca2 +] inside intracellular organelles, both by luminescence and by fluorescence. The low-affinity variant GAP3 is adequate for ratiometric imaging in the endoplasmic reticulum and Golgi apparatus, and it can be combined with conventional synthetic indicators for simultaneous measurements of cytosolic Ca2 +. GAP is bioorthogonal as it does not have mammalian homologues, and it is robust and functionally expressed in transgenic flies and mice, where it can be used for Ca2 + measurements ex vivo and in vivo to explore animal models of health and disease. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.Ministerio de Economía, Industria y Competitividad (Project BFU2014-53469P)Instituto de Salud Carlos III (TerCel; RD16/0011/0003

Using aequorin probes to measure Ca2+ in intracellular organelles

Producción CientíficaAequorins are excellent tools for measuring intra-organellar Ca2+ and assessing its role in physiological and pathological functions. Here we review targeting strategies to express aequorins in various organelles. We address critical topics such as probe affinity tuning as well as normalization and calibration of the signal. We also focus on bioluminescent Ca2+ imaging in nucleus or mitochondria of living cells. Finally, recent advances with a new chimeric GFP-aequorin protein (GAP), which can be used either as luminescent or fluorescent Ca2+ probe, are presented. GAP is robustly expressed in transgenic flies and mice, where it has proven to be a suitable Ca2+ indicator for monitoring physiological Ca2+ signaling ex vivo and in vivo.Ministerio de Economía, Industria y Competitividad (Project BFU2014-53469P)Instituto de Salud Carlos III (TerCel, RD16/0011/0003

Caffeine chelates calcium in the lumen of the endoplasmic reticulum

Producción CientíficaCytosolic Ca2+ signals are often amplified by massive calcium release from the endoplasmic reticulum (ER). This calcium-induced calcium release (CICR) occurs by activation of an ER Ca2+ channel, the ryanodine receptor (RyR), which is facilitated by both cytosolic- and ER Ca2+ levels. Caffeine sensitizes RyR to Ca2+ and promotes ER Ca2+ release at basal cytosolic Ca2+ levels. This outcome is frequently used as a readout for the presence of CICR. By monitoring ER luminal Ca2+ with the low-affinity genetic Ca2+ probe erGAP3, we find here that application of 50 mM caffeine rapidly reduces the Ca2+ content of the ER in HeLa cells by ∼50%. Interestingly, this apparent ER Ca2+ release does not go along with the expected cytosolic Ca2+ increase. These results can be explained by Ca2+ chelation by caffeine inside the ER. Ca2+-overloaded mitochondria also display a drop of the matrix Ca2+ concentration upon caffeine addition. In contrast, in the cytosol, with a low free Ca2+ concentration (10−7 M), no chelation is observed. Expression of RyR3 sensitizes the responses to caffeine with effects both in the ER (increase in Ca2+ release) and in the cytosol (increase in Ca2+ peak) at low caffeine concentrations (0.3–1 mM) that have no effects in control cells. Our results illustrate the fact that simultaneous monitoring of both cytosolic- and ER Ca2+ are necessary to understand the action of caffeine and raise concerns against the use of high concentrations of caffeine as a readout of the presence of CICR.Ministerio de Economía, Industria y Competitividad (Project BFU2017-83066-P

GAP, an aequorin-based fluorescent indicator for imaging Ca2+ in organelles

Producción CientíficaGenetically encoded calcium indicators allow monitoring subcellular Ca2+ signals inside organelles. Most genetically encoded calcium indicators are fusions of endogenous calcium-binding proteins whose functionality in vivo may be perturbed by competition with cellular partners.We describe here a novel family of fluorescent Ca2+ sensors based on the fusion of two Aequorea victoria proteins, GFP and apo-aequorin (GAP). GAP exhibited a unique combination of features: dual-excitation ratiometric imaging, high dynamic range, good signal-to-noise ratio, insensitivity to pH and Mg2+, tunable Ca2+ affinity, uncomplicated calibration, and targetability to five distinct organelles. Moreover, transgenic mice for endoplasmic reticulum-targeted GAP exhibited a robust long-term expression that correlated well with its reproducible performance in various neural tissues. This biosensor fills a gap in the actual repertoire of Ca2+ indicators for organelles and becomes a valuable tool for in vivo Ca2+ imaging applications

Mitochondrial cristae-remodeling protein OPA1 in POMC neurons couples Ca2+ homeostasis with adipose tissue lipolysis

© 2021 The Authors.Appropriate cristae remodeling is a determinant of mitochondrial function and bioenergetics and thus represents a crucial process for cellular metabolic adaptations. Here, we show that mitochondrial cristae architecture and expression of the master cristae-remodeling protein OPA1 in proopiomelanocortin (POMC) neurons, which are key metabolic sensors implicated in energy balance control, is affected by fluctuations in nutrient availability. Genetic inactivation of OPA1 in POMC neurons causes dramatic alterations in cristae topology, mitochondrial Ca2+ handling, reduction in alpha-melanocyte stimulating hormone (α-MSH) in target areas, hyperphagia, and attenuated white adipose tissue (WAT) lipolysis resulting in obesity. Pharmacological blockade of mitochondrial Ca2+ influx restores α-MSH and the lipolytic program, while improving the metabolic defects of mutant mice. Chemogenetic manipulation of POMC neurons confirms a role in lipolysis control. Our results unveil a novel axis that connects OPA1 in POMC neurons with mitochondrial cristae, Ca2+ homeostasis, and WAT lipolysis in the regulation of energy balance.This work was supported by Agencia Estatal de Investigación y Fondo Social Europeo, Proyecto BFU2016-76973-R FEDER (C.V.A.); AG052005, AG052986, AG051459, DK111178 from NIH and NKFI-KKP-126998 from Hungarian National Research, Development and Innovation Office (T.L.H.); MR/P009824/2 from Medical Research Council UK (G.D.); and Ayudas Fundación BBVA a Investigadores y Creadores Culturales (2015), European Research Council (ERC) under the European Union’s Horizon 2020 Research And Innovation Program (grant agreement 725004) and CERCA Programme/Generalitat de Catalunya (M.C.). A.O. is supported by a Miguel Servet contract (CP19/00083) from Instituto de Salud Carlos III and co-financed by FEDER

Mitochondrial cristae-remodeling protein OPA1 in POMC neurons couples Ca2+ homeostasis with adipose tissue lipolysis

Appropriate cristae remodeling is a determinant of mitochondrial function and bioenergetics and thus represents a crucial process for cellular metabolic adaptations. Here, we show that mitochondrial cristae architecture and expression of the master cristae-remodeling protein OPA1 in proopiomelanocortin (POMC) neurons, which are key metabolic sensors implicated in energy balance control, is affected by fluctuations in nutrient availability. Genetic inactivation of OPA1 in POMC neurons causes dramatic alterations in cristae topology, mitochondrial Ca2+ handling, reduction in alpha-melanocyte stimulating hormone (α-MSH) in target areas, hyperphagia, and attenuated white adipose tissue (WAT) lipolysis resulting in obesity. Pharmacological blockade of mitochondrial Ca2+ influx restores α-MSH and the lipolytic program, while improving the metabolic defects of mutant mice. Chemogenetic manipulation of POMC neurons confirms a role in lipolysis control. Our results unveil a novel axis that connects OPA1 in POMC neurons with mitochondrial cristae, Ca2+ homeostasis, and WAT lipolysis in the regulation of energy balance

Impact of CD4 and CD8 dynamics and viral rebounds on loss of virological control in HIV controllers

Objective: HIV controllers (HICs) spontaneously maintain HIV viral replication at low level without antiretroviral therapy (ART), a small number of whom will eventually lose this ability to control HIV viremia. The objective was to identify factors associated with loss of virological control. Methods: HICs were identified in COHERE on the basis of \ue2\u89\ua55 consecutive viral loads (VL) \ue2\u89\ua4500 copies/mL over \ue2\u89\ua51 year whilst ART-naive, with the last VL \ue2\u89\ua4500 copies/mL measured \ue2\u89\ua55 years after HIV diagnosis. Loss of virological control was defined as 2 consecutive VL >2000 copies/mL. Duration of HIV control was described using cumulative incidence method, considering loss of virological control, ART initiation and death during virological control as competing outcomes. Factors associated with loss of virological control were identified using Cox models. CD4 and CD8 dynamics were described using mixed-effect linear models. Results: We identified 1067 HICs; 86 lost virological control, 293 initiated ART, and 13 died during virological control. Six years after confirmation of HIC status, the probability of losing virological control, initiating ART and dying were 13%, 37%, and 2%. Current lower CD4/CD8 ratio and a history of transient viral rebounds were associated with an increased risk of losing virological control. CD4 declined and CD8 increased before loss of virological control, and before viral rebounds. Discussion: Expansion of CD8 and decline of CD4 during HIV control may result from repeated low-level viremia. Our findings suggest that in addition to superinfection, other mechanisms, such as low grade viral replication, can lead to loss of virological control in HICs

Reinterpretation of LHC Results for New Physics: Status and recommendations after Run 2

We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentation of LHC results in order to better enable reinterpretation in the future. We also provide a brief description of existing software reinterpretation frameworks and recent global analyses of new physics that make use of the current data