LEAP-2, un nuevo elemento del sistema de ghrelina en la regulación del balance energético

La ghrelina es el ligando endógeno para el receptor de secretagogos de la hormona de crecimiento (GHSR1a), su unión al receptor favorece la liberación de la hormona de crecimiento (GH) y produce efectos orexigénicos y adipogénicos. Recientemente se ha descubierto la interacción del péptido antimicrobiano que se expresa en el hígádo-2 (LEAP-2) con GHSR, lo que ha suscitado mucho interés al mostrarse el papel antagónico de LEAP-2 sobre ghrelina en el metabolismo energético. En esta tesis doctoral se estudian los efectos centrales de LEAP-2 y ghrelina sobre la ingesta en distintos contextos fisiológicos como el envejecimiento y obesidad. Demostrando que los efectos opuestos de ambas moléculas sobre la ingesta contribuyen al mantenimiento de la homeostasis energética

Spatially explicit assessment of genetic variation to inform conservation effort for an endangered Mediterranean conifer, Cedrus atlantica

Preserving the genetic diversity of forest species is critical for maintaining their adaptive potential and allowing for generation turnover in forest ecosystems. Considering an uncertain future, it is necessary to establish reliable genetic conservation strategies to optimize the genetic variation preserved within populations in a spatially explicit context to assist decision-makers. Hence, we aimed to incorporate genetic information into spatially designed conservation actions. Cedrus atlantica is a large, long-lived conifer native to the mountains of North Africa, threatened by extinction. The relevant genetic units for conservation were selected using Bayesian analysis. The relative contribution of the populations to the genetic pool that maximized the species' genetic diversity was calculated to design an optimal seed bank. Finally, the relationship between the genetic composition and bioclimatic variables was estimated and projected throughout the study area under current and future climatic conditions. Three relevant genetic units were found for C. atlantica conservation that maximizes genetic diversity in a spatial context. Bioclimatic variables with the highest influence on genetic composition were closely related to climate warming and decreased soil water availability. We identified the role of genetic markers in designing a reliable conservation strategy for forest trees considering climate change, increased deforestation, and aridity. Projections of genetic composition due to the climate in the study region of North Africa provide spatially explicit guidance for optimizing the selection and preservation of seed banks

Are rates of thermal niche evolution in cave beetles enough to cope with climate change?

Póster presentada en la conferencia Adapting to Global Change in the Mediterranean hotspot (AGCM), celebrada en Sevilla del 18 al 20 de septiembre de 2013.Climate change has become one of the main threats to global biodiversity. However, the extent to which species are threatened by climate change depends on how they respond to these new climatic conditions. They can disperse to more suitable locations, or they can cope through phenotypic plasticity and, ultimately, via evolutionary adaptation. Most of the studies of the evolutionary and biogeographical consequences of climatic change have been done with terrestrial, mainly vertebrate species. These models present some important uncertainties, as depending on the use of different microhabitats at different times within the same area the species can be exposed to a range of temperature or humidity sometimes much wider than the change predicted by the most pessimistic scenarios of climate change. The possibility of range movement tracking suitable habitats is also a confounding factor when trying to infer the conditions at which these species were subjected in the past. Here we present a system in which most of these uncertainties do not apply: the deep subterranean environment. The temperature of a cave is highly constant through the year and can be estimated from the mean annual temperature of the surface, and the humidity is always near to the saturation point. These conditions are homogeneous through all possible microhabitats within a cave system, and constant through the year. Most highly specialized cave species have also extremely narrow geographical ranges, which allows to trace their geographical movements through several cladogenetic processes. We focused on a well defined clade of troglobitic beetles of the tribe Leptodirini (Coleoptera, Leiodidae) living in the North-eastern Iberian Peninsula (from the Pyrenees to the coast of Catalonia), including ca. 140 taxa. Most of them are narrow endemic species with a well known distribution. We aim to estimate the rate of thermal niche evolution using two approaches: i) we first reconstructed a minimum rate of evolutionary change from a time calibrated phylogeny using only the current thermal niche of the species; and ii) we then introduced the constraint of the paleotemperatures of the areas occupied by these species during the Pleistocene glacial periods. We finally compare these rates with predicted rates of climate change from 2000 to 2100 for the same areas.Peer Reviewe

Hypothalamic Mitochondrial Dysfunction as a Target in Obesity and Metabolic Disease

Mitochondria are important organelles for the adaptation to energy demand that play a central role in bioenergetics metabolism. The mitochondrial architecture and mitochondrial machinery exhibits a high degree of adaptation in relation to nutrient availability. On the other hand, its disruption markedly affects energy homeostasis. The brain, more specifically the hypothalamus, is the main hub that controls energy homeostasis. Nevertheless, until now, almost all studies in relation to mitochondrial dysfunction and energy metabolism have focused in peripheral tissues like brown adipose tissue, muscle, and pancreas. In this review, we highlight the relevance of the hypothalamus and the influence on mitochondrial machinery in its function as well as its consequences in terms of alterations in both energy and metabolic homeostasis

Spatially explicit assessment of genetic variation to inform conservation effort for an endangered Mediterranean conifer, Cedrus atlantica

Preserving the genetic diversity of forest species is critical for maintaining their adaptive potential and allowing for generation turnover in forest ecosystems. Considering an uncertain future, it is necessary to establish reliable genetic conservation strategies to optimize the genetic variation preserved within populations in a spatially explicit context to assist decision-makers. Hence, we aimed to incorporate genetic information into spatially designed conservation actions. Cedrus atlantica is a large, long-lived conifer native to the mountains of North Africa, threatened by extinction. The relevant genetic units for conservation were selected using Bayesian analysis. The relative contribution of the populations to the genetic pool that maximized the species' genetic diversity was calculated to design an optimal seed bank. Finally, the relationship between the genetic composition and bioclimatic variables was estimated and projected throughout the study area under current and future climatic conditions. Three relevant genetic units were found for C. atlantica conservation that maximizes genetic diversity in a spatial context. Bioclimatic variables with the highest influence on genetic composition were closely related to climate warming and decreased soil water availability. We identified the role of genetic markers in designing a reliable conservation strategy for forest trees considering climate change, increased deforestation, and aridity. Projections of genetic composition due to the climate in the study region of North Africa provide spatially explicit guidance for optimizing the selection and preservation of seed banks

Adiciones y correcciones a la flora bentónica marina del Atlántico ibérico norte

Continuando con los estudios para la actualización del inventariado de la flora bentónica marina del Atlántico Ibérico. En este trabajo se incluye nueva información de distribución para 18 especies (3 Cyanobacteria, 9 Rhodophyta, 4 Ochrophyta, 2 Chlorophyta) de algas bentónicas marinas, recolectadas en el intermareal y submareal de 46 localidades del atlántico ibérico norte. Atendiendo a la distribución de las especies recolectadas, cabe destacar una nueva cita para Europa (Plocamium cf. ovicorne), 3 nuevas citas para Galicia (Calothrix consociata, Lyngbya martensiana y Centroceras gasparrinii), 14 nuevas citas provinciales y 8 segundas citas provinciales. Además dos especies (Spermothamnion strictum y Punctaria plantaginea) son excluidas de la flora de Galicia después, de estudiar el único material de herbario testigo de las citas.et al. 2005a-b, 2006, 2008, 2012, 2014, 2015, 2016), se presentan nuevas citas y correcciones florísticas que completan el actual inventario de la biodiversidad marina de Galicia (Bañón 2017). La mayoría de las muestras se conservaron en formalina al 4% y la conservación definitiva se realizó en pliegos de herbario, depositados en el herbario de la Universidad de Santiago de Compostela (SANT), así como en preparaciones semipermanentes en Karo®. También se estudiaron pliegos de herbario del Nationaal Herbarium Nederland, para la verificación o corrección de citas antiguas. Paralelamente, se conservaron fragmentos sin formolar de algunas especies en gel de sílice para estudios moleculares

LEAP-2 Counteracts Ghrelin-Induced Food Intake in a Nutrient, Growth Hormone and Age Independent Manner

Data gleaned recently shows that ghrelin, a stomach derived peptide, and liver-expressed-antimicrobial peptide 2 (LEAP-2) play opposite roles on food intake. However, the data available with LEAP-2 in relation to in vivo studies are still very scanty and some key questions regarding the interplay among ghrelin and LEAP-2 remain to be answered. In this work, using rats and mice, we study fasting-induced food intake as well as testing the effect of diet exposure, e.g., standard diet and high fat diet, in terms of ghrelin-induced food intake. The anorexigenic effect of LEAP-2 on fasting induced food intake appears to be dependent on energy stores, being more evident in ob/ob than in wild type mice and also in animals exposed to high fat diet. On the other hand, LEAP-2 administration markedly inhibited ghrelin-induced food intake in lean, obese (ob/ob and DIO) mice, aged rats and GH-deficient dwarf rats. In contrast, the inhibitory effect on glucose levels can only be observed in some specific experimental models indicating that the mechanisms involved are likely to be quite different. Taken together from these data, LEAP-2 emerged as a potential candidate to be therapeutically useful in obesity

Adiciones y correcciones a la flora bentónica marina del Atlántico ibérico norte

Continuando con los estudios para la actualización del inventariado de la flora bentónica marina del Atlántico Ibérico.En este trabajo se incluye nueva información de distribución para 18 especies (3 Cyanobacteria, 9 Rhodophyta, 4 Ochrophyta, 2 Chlorophyta) de algas bentónicas marinas, recolectadas en el intermareal y submareal de 46 localidades del atlántico ibérico norte. Atendiendo a la distribución de las especies recolectadas, cabe destacar una nueva cita para Europa (Plocamium cf. ovicorne), 3 nuevas citas para Galicia (Calothrix consociata, Lyngbya martensiana y Centroceras gasparrinii), 14 nuevas citas provinciales y 8 segundas citas provinciales. Además dos especies (Spermothamnion strictum y Punctaria plantaginea) son excluidas de la flora de Galicia después, de estudiar el único material de herbario testigo de las citas.et al. 2005a-b, 2006, 2008, 2012, 2014, 2015, 2016), se presentan nuevas citas y correcciones florísticas que completan el actual inventario de la biodiversidad marina de Galicia (Bañón 2017). La mayoría de las muestras se conservaron en formalina al 4% y la conservación definitiva se realizó en pliegos de herbario, depositados en el herbario de la Universidad de Santiago de Compostela (SANT), así como en preparaciones semipermanentes en Karo®. También se estudiaron pliegos de herbario del Nationaal Herbarium Nederland, para la verificación o corrección de citas antiguas. Paralelamente, se conservaron fragmentos sin formolar de algunas especies en gel de sílice para estudios moleculares