Evolutionary conservation of transcription factors affecting longevity

Gene expression can be optimised for health and longevity through manipulation of transcription factor (TF) activity. The effects of many such TFs are conserved between animal species indicating evolutionary conservation of underlying mechanisms. Lifespan-determining TFs regulate a plethora of cellular and organismal functions, including stress resistance, metabolism and growth. They interact with each other both within and between cells. Manipulating their activity in a single cell type can often be sufficient to insure longevity. The evolutionary conservation of their effects on ageing is most likely a reflection of the conservation of their function in processes, such as reproduction, growth, and metabolism, that are important earlier in life. Their effects on early and late life can, however, often be uncoupled

The Chandra Dust Scattering Halo of Galactic Center transient Swift J174540.7-290015

We report the detection of a dust scattering halo around a recently discovered X-ray transient, Swift J174540.7-290015, which in early February of 2016 underwent one of the brightest outbursts (F_X ~ 5e-10 erg/cm^2/s) observed from a compact object in the Galactic Center field. We analyze four Chandra images that were taken as follow-up observations to Swift discoveries of new Galactic Center transients. After adjusting our spectral extraction for the effects of detector pileup, we construct a point spread function for each observation and compare it to the GC field before the outburst. We find residual surface brightness around Swift J174540.7-290015, which has a shape and temporal evolution consistent with the behavior expected from X-rays scattered by foreground dust. We examine the spectral properties of the source, which shows evidence that the object transitioned from a soft to hard spectral state as it faded below L_X ~ 1e36 erg/s. This behavior is consistent with the hypothesis that the object is a low mass X-ray binary in the Galactic Center.Comment: Accepted for publication in Ap

A hematite photoelectrode grown on porous and conductive SnO₂ ceramics for solar-driven water splitting

Photoelectrochemical water splitting using solar energy is a highly promising technology to produce hydrogen as an environmentally friendly and renewable fuel with high-energy density. This approach requires the development of appropriate photoelectrode materials and substrates, which are low-cost and applicable for the fabrication of large area electrodes. In this work, hematite photoelectrodes are grown by aerosol assisted chemical vapour deposition (AA-CVD) onto highly-conductive and bulk porous SnO2 (Sb-doped) ceramic substrates. For such photoelectrodes, the photocurrent density of 2.8 mA cm-2 is achieved in aqueous 0.1 M NaOH under blue LED illumination (λ = 455 nm; 198 mW cm-2) at 1.23 V vs. RHE (reversible hydrogen electrode). This relatively good photoelectrochemical performance of the photoelectrode is achieved despite the simple fabrication process. Good performance is suggested to be related to the three-dimensional morphology of the porous ceramic substrate resulting in excellent light-driven charge carrier harvesting. The porosity of the ceramic substrate allows growth of the photoactive layer (SnO2-grains covered by hematite) to a depth of some micrometers, whereas the thickness of Fe2O3-coating on individual grains is only about 100–150 nm. This architecture of the photoactive layer assures a good light absorption and it creates favourable conditions for charge separation and transport.</p

Quantitative dynamic AFM hydration-adsorption design for hygroscopic and bio-compatible polymeric nanofibers

Nanomechanical properties of bio-compatible polymers play crucial roles in tissue engineering scaffolds and filtration devices. The hygro-mechanical properties of those fibers have been mostly studied from a very coarse perspective, reaching a micrometer-scale. However, at the nanoscale the mechanical response of polymeric fibers becomes more challenging due to both experimental-theoretical limitations. In particular, the environment-mediated mechanical response of polymer-fibers demands advanced models that consider sub-nanometric changes in the local structure of water-intercalated with single-polymer-chains. Herein, atomic force-microscopy (AFM) experiments, analytical theory, and simulations are combined to determine the elastic properties of the nanofibers as a function of relative humidity. The effect of morphological changes from the adsorbed water-layer, and an ensemble of inter-chain interaction strength and morphological changes at peak-forces are explored. For the polyvinyl-alcohol (PVA) nanofibers, considerable differences are found, which are strongly dependent on the molecular signatures of hydration-adsorption at a polymer-chain level. Here, the semi-empirical model plays a key role in properly interpreting experiments by evaluating only a few observables, the height, phase (dissipation), and alternatively the force-distance curves. Beyond the semi-empirical model, an analytical approach to calculate the peak-forces of hygroscopic materials is featured, which enables on-the-fly characterization of the samples, and thus the interactive adjustment of operational-parameter

Genética de poblaciones amazónicas: la historia evolutiva del jaguar, ocelote, delfín rosado, mono lanudo y piurí, reconstruida a partir de sus genes

The Amazon has more than the half of the world's biodiversity. Nevertheless, the major fraction of the Amazon species has unknown evolutionary histories. This is also certain for mammals and birds. Population genetics, employing molecular markers and theoretical mathematics models, can reconstruct these evolutionary histories and offer very powerful tools for the application of correct conservation politics. Herein, we show a comparative view of population genetics results obtained for Amazon populations of jaguar, ocelot, pink river dolphin, woolly monkey and wattled curassow and provide recommendation for their biological conservation. Each species showed its own specific evolutionary particularities, characteristics that were not shared by the other species. This finding should be taken into consideration for any effective biological conservation program. Key words: Amazon, Population genetics, Panthera, Leopardus, Inia, Lagothrix, Crax.El Amazonas contiene más de la mitad de la biodiversidad a escala mundial. Sin embargo, muchas de las especies que alberga, poseen historias evolutivas totalmente desconocidas. Esto incluye el caso de los mamíferos y de las aves. La genética de poblaciones, mediante el uso de marcadores moleculares, modelos y metodologías matemáticas, puede intentar reconstruir esa historia evolutiva y ofrecer herramientas efectivas para la aplicación de políticas correctas de conservación. Se muestra aquí un resumen de los estudios genético realizados en poblaciones amazónicas de jaguar, ocelote, delfín rosado, mono lanudo y piurí y se proponen algunas recomendaciones para su conservación biológica. En cada especie se observaron particularidades evolutivas propias no compartidas por las otras especies. Este hecho debe ser recogido por cualquier programa de conservación que pretenda ser efectivo. Palabras clave: Amazonas, Genética de poblaciones, Panthera, Leopardus, Inia, Lagothrix, Crax

Using of Hydroponic solution on the irrigation water of barley hidroponic sprouts (Hordeum vulgare)

El presente trabajo de investigación se realizó en el centro poblado Nuevo Mocse de Lambayeque del 16 al 31 de Diciembre de 2014 y tuvo como objetivos determinar la mejor dosis de solución nutritiva de macronutrientes A y micronutrientes B en el agua de riego de germinado hidropónico de cebada; b) Determinar el valor nutricional del germinado hidropónico de cebada regada con diferentes dosis de solución nutritiva de macronutrientes A y micronutrientes B y c) Determinar el rendimiento del Germinado Hidropónico de cebada (Hordeum vulgare L.) regada con diferentes dosis de solución nutritiva de macronutrientes A y micronutrientes B. Para lograrlos se implementaron 6 tratamientos con 6 repeticiones cada uno: T0 : GH de cebada sin solución nutritiva en el agua de riego; T1: 1.00 ml de solución nutritiva A y 0.50 ml de solución nutritiva B en agua de riego ; T2: 0.50 ml de solución nutritiva A y 0.125 ml de solución nutritiva B en agua de riego; T3: 0.75 ml de solución nutritiva A y 0.25 ml de solución nutritiva B en agua de riego; T4: 1.25 ml de solución nutritiva A y 0.75 ml de solución nutritiva B en agua de riego; T5: 1.50 ml de solución nutritiva A y 1.00 ml de solución nutritiva B en agua de riego. Los resultados demostraron la existencia de diferencias estadísticas significativas entre tratamientos obteniendo los mejores resultados con T3 utilizando 0.75 ml de solución A y 0.25 ml de solución B diluidos en 4 litros de agua de riego suministrados desde el día 4 hasta el día 8 post siembra en bandejas.This research was conducted in the town of New Mocce at Lambayeque from 16 to 31 December 2014. The objective was to: a) determine the best dose of nutrient solution of macronutrients (A) and micro-nutrients ( B) in hydroponic irrigation water germinated barley; b) Determine the nutritional value of barley sprouts watered with different doses of A and B; c) Determine the performance of germinated barley (Hordeum vulgare) watered with different doses of A and B. To achieve it 6 treatments with 6 replicates each were implemented: T0, germinated barley without hydroponic nutrient solution in irrigation water; T1, 1 ml of A and 0.5 ml of B in water for irrigation; T2, 0.5 ml of A and 0.125 ml of B in water for irrigation; T3, 0.75 ml of A and 0.25 ml of B in water for irrigation; T4, 1.25 ml of A and 0.75 ml B in water for irrigation; T5, 1.50 ml of A and 1 ml B in water for irrigation. The results showed statistically significant differences between treatments; the best results with T3, using 0.75 ml of A and 0.25 ml of B diluted in 4 liters of irrigation water supplied from 4 to 8 days post-seeding tray

¿EXISTE RELACIÓN ENTRE EL PARASITISMO Y LA AUTOTOMÍA DE COLA EN LAGARTIJAS? CASO DE ESTUDIO EN LIOLAEMUS DARWINII (IGUANIA: LIOLAEMIDAE)

Tail autotomy acts as anti-predatory mechanism in a great diversity of lizard species. Research links tail loss with various aspects of lizard life history. However, parasitic aspects are not taken into consideration, despite being a variable that greatly influences reptile ecology. For the first time, it is proposed that the existence of a relationship between the caudal autotomy of a lizard species is related to its parasitic condition. We studied 30 adult specimens of Liolaemus darwinii Bell, 1843 in the desert of Monte, San Juan province, Argentina. Autotomy was used as a direct measure of predator-prey interaction. A series of variables were analyzed that could be related to tail autotomy. The following variables were studied using generalized linear models: sex, environments (disturbed vs. conserved), condition (parasitized vs. not parasitized), parasitic intensity, weights (g) and snout-vent length (Lhc). The dependent variable (presence of tail: 1, absence of tail: 0) was adjusted to a binomial distribution, whose link function is logit (logistic regression). Only the variable parasitized vs. non-parasitized condition was significantly associated with tail autotomy. Parasitized individuals all have cut tails or in some stage of regeneration. Individuals that were not parasitized had complete tails (intact). The results establish for the first time a relationship between parasitism and tail loss in L. darwinii. The results are discussed in a behavioral ecological context and physiological resource allocation. In addition, our work is an approach to understanding the role of parasites in the ecology of L. darwinii in the Monte desert in Argentina.La autotomía de cola es usada como estrategia antipredatoria en diversas especies de lagartijas. Las investigaciones relacionan la pérdida de cola con diversos aspectos en la historia de vida en reptiles. Sin embargo, los aspectos parasitarios no son tenidos en cuenta, a pesar de ser una variable que influye enormemente en la ecología de reptiles. Por primera vez, se propone la existencia de una relación entre la autotomía caudal de una especie de lagartija con su condición parasitaria. Se analizaron 30 ejemplares adultos de Liolaemus darwinii Bell, 1843 capturados en el desierto del Monte, provincia de San Juan, Argentina. Se utilizó la autotomía caudal como medida directa de interacción entre depredador y presa. Se analizaron cinco variables que podrían relacionarse con la autotomía de cola. Para ello, fueron estudiadas mediante modelos lineales generalizados las variables; sexos, ambientes (perturbado/ conservado), condición (parasitado/ no parasitado), intensidad parasitaria, pesos (g) y longitud hocico- cloaca (Lhc). La variable dependiente (presencia cola: 1, ausencia de cola: 0) se ajustó a una dis­tribución binomial, cuya función de enlace es logit (regresión logística). Solo la variable condición parasitado/ no parasitado se asoció significativamente con la autotomía de cola. Los individuos que se encontraban parasitados, presentaban en su mayoría colas cortadas o en alguna etapa de su regeneración. Sin embargo, los individuos que no estaban parasitados presentaban colas completas (intactas). Los resultados establecen por primera vez una relación entre el parasitismo y la pérdida de cola en L. darwinii. Se discuten los resultados en un contexto ecológico comportamental y asignación fisiológica de recurso. Además, nuestro trabajo es una aproximación al entendimiento del rol de los parásitos en la ecología de L. darwinii en el desierto del Monte en Argentina

Partial inhibition of RNA polymerase I promotes animal health and longevity

Health and survival in old age can be improved by changes in gene expression. RNA polymerase (Pol) I is the essential, conserved enzyme whose task is to generate the pre-ribosomal RNA (rRNA). We find that reducing the levels of Pol I activity is sufficient to extend lifespan in the fruit fly. This effect can be recapitulated by partial, adult-restricted inhibition, with both enterocytes and stem cells of the adult midgut emerging as important cell types. In stem cells, Pol I appears to act in the same longevity pathway as Pol III, implicating rRNA synthesis in these cells as the key lifespan determinant. Importantly, reduction in Pol I activity delays broad, age-related impairment and pathology, improving the function of diverse organ systems. Hence, our study shows that Pol I activity in the adult drives systemic, age-related decline in animal health and anticipates mortality