158 research outputs found
Sedimentology and stratigraphic architecture of Barremian synrift barrier island–estuarine depositional systems from blended field and drone-derived data
The Lower Cretaceous (Barremian) Camarillas Formation in the Galve Sub-basin of eastern Spain is an exceptionally muddy, synrift, aggradational then retrogradational paralic succession. Deposition within these arid, equatorial paralic systems was strongly controlled by crustal rifting of the Iberia plate linked to the geodynamic evolution of the Atlantic Ocean, the Bay of Biscay and the Tethys Ocean. Although synsedimentary extensional tectonics controlled thickness and facies distributions, the parasequence stacking patterns point to a superimposed high-order allogenic control on the paralic succession. Field data and drone imagery are combined to document changes in sedimentology and three-dimensional stratigraphic architecture of these deposits to interpret changes in depositional environments as this basin filled. Three evolutionary stages are identified: (i) tide-dominated estuary; (ii) mixed-energy estuary, with a well-developed wave-dominated barrier island system; and (iii) barrier island–tidal inlet suite. An exceptional record of back-barrier-island depositional interactions is preserved in this high-subsidence, extensional-basin setting, including deposition of washover fans, flood-tidal deltas and ebb-tidal deltas. Drone-derived imagery facilitates three-dimensional architectural characterization of these complex paralic deposits, including multi-episodic tidal inlets, and correlation of basin scale stratigraphic markers. Spatio-temporal interactions between climate change, sea-level variations and rift-related subsidence generated complex estuarine and barrier island geobodies. The general transgressive trend recorded in the Camarillas Formation correlates well with global eustatic sea-level rise during the Barremian
Salt tectonics vs. inversion tectonics: The anticlines of the western Maestrazgo revisited (eastern Iberian Chain, Spain)
Many works in the last decades underline the role of evaporites, not just as a conditioning factor but as the engine for subsidence and eventually basin inversion. The western Mediterranean alpine ranges are being investigated in this regard because of the presence of discontinuous units of Permian to Triassic evaporites, deposited in the western Tethys basins. This work presents a thorough analysis of two particular structures (Cañada Vellida and Miravete anticlines) in the intraplate Maestrazgo basin (eastern Iberian Chain, Spain) in which evidence to support their reinterpretation as salt-driven structures have been recently reported. Our analysis includes (i) a comprehensive stratigraphic and structural study of the folds along their entire trace, (ii) the compilation of thickness and distribution of evaporite–bearing and supraevaporite units, paying special attention to changes in the thickness of units in relation to anticlines, and (iii) the study of fault patterns, sometimes in relation to the mechanical stratigraphy. All three aspects are also documented and discussed on a regional scale. The new data and interpretations reported here reinforce the extensional origin of the Late Jurassic–Early Cretaceous basins, and the role of regional extensional tectonics as the responsible for the development of first-order syn-sedimentary normal fault zones driving the formation and evolution of sub-basins. These basins were subsequently inverted and deformed, including the formation of complex, box-geometry anticlines that, in their turn, controlled deposition in Cenozoic basins. The review of the arguments that support the alternative of salt tectonics for the origin of such anticlines has allowed us to delve into the sedimentary and tectonic evolution of the inverted extensional basins and to propose a specific model for the development of these faulted anticlines. The role of salt levels and other interlayered detachments in the structuring of sedimentary basins and their inversion is also pondered. The observations in the eastern Iberian Chain reported here have implications to assess ongoing reinterpretations in terms of salt tectonics in other alpine basins and ranges of the western Mediterranean
Digestibilidad in vitro del dsRNA específico por enzimas del tracto digestivo del camarón Litopenaeus vannamei
Objective. The digestibility of specific dsRNA by action of the enzymes of digestive tract of the whiteleg shrimp Litopenaeus vannamei was determined in vitro. Materials and methods. Digestive enzyme activity (amylase, lipase, protease, DNase and RNase) was measured in the stomach, digestive gland, and anterior, middle, and posterior intestine of juvenile shrimp, and the digestibility of DNA, RNA and the dsRNA-ORF89, specific to WSSV, was determined by in vitro assays, as well as electrophoretic and densitometric analyses. Results. The highest enzymatic activity was found in the digestive gland: amylase (81.41%), lipase (92.60%), protease (78.20%), DNase (90.85%), and RNase (93.14%). The highest digestive capacity against DNA, RNA, and dsRNA was found in the digestive gland (5.11 ng of DNA per minute, 8.55 ng of RNA per minute, and 1.48 ng dsRNA per minute). Conclusions. The highest digestibility of dsRNA-ORF89, specific to WSSV, was found in the digestive gland, whereas the lowest digestibility was observed in the posterior intestine. This is the first report regarding the digestibility of dsRNA-ORF89 by whiteleg shrimp digestive tract enzymes, with potential therapeutic importance in shrimp culture to prevent WSSV disease through balanced feed.Objetivo. La digestibilidad del dsRNA específico para el virus de la mancha blanca (WSSV) por acción de las enzimas del tracto digestivo del camarón Litopenaeus vannamei fue analizada in vitro. Material y métodos. Se midió la actividad de enzimas digestivas (proteasa, amilasa, lipasa, ADNasa y ARNasa) en el estómago, la glándula digestiva, el intestino anterior, medio y posterior en juveniles de camarón patiblanco y se evaluó la digestibilidad de ácidos nucleicos ADN, ARN y dsRNA-ORF89 especifico contra el virus WSSV, por análisis electroforéticos y densitometría. Resultados. La actividad enzimática más alta se encontró en la glándula digestiva del camarón: amilasa (81.41%), lipasa (92.60%), proteasa (78.20%), ADNasa (90.85%) y ARNasa (93.14%). Se evidenció la capacidad digestiva del camarón patiblanco contra el ADN, ARN y dsRNA-ORF89 encontrando en la glándula digestiva la mayor digestión (5.11 ng de ADN por minuto, 8.55 ng de ARN por minuto y 1.48 ng de dsRNA por minuto). Conclusiones. La mayor digestibilidad del dsRNA-ORF89, específico contra el virus WSSV, se encontró en la glándula digestiva y la menor en el intestino posterior. Este es el primer informe relacionado con la digestibilidad del dsRNA-ORF89 por las enzimas del camarón patiblanco con potencial importancia terapéutica en el cultivo de camarón para prevenir la enfermedad del WSSV a través del alimento balanceado
Ice-rafted dropstones at midlatitudes in the Cretaceous of continental Iberia
The Cretaceous is widely considered to have been a period subjected to super-greenhouse conditions. Here, we provide multiscale sedimentologic evidence of glaciers developing at mid-paleolatitudes (∼45°N) in continental Iberia during the Hauterivian cold snap. Striated and faceted ice-rafted glacial dropstones (cobble to boulder size) and striated and grooved silt- to sand-sized grains (ice-rafted debris [IRD]) occur in a lacustrine sequence of the Enciso Group in the eastern Cameros Basin, Spain. The ice-rafted materials constitute the first evidence reported for a Cretaceous continental cryospheric record in Europe, and they are attributed to calving of glacier snouts, releasing icebergs into an ice-contact lake. The sedimentary succession resembles glacial-deglacial records in lakes overridden by the late Pleistocene Laurentide Ice Sheet in eastern Arctic Canada. The Iberian glacial succession was coeval with plateau permafrost in Asia and IRD records in the Arctic and Australia, revealing a stronger than previously thought cryosphere during the global Hauterivian cold snap
A new interpretation of the Escucha and Utrillas Fm in their reference sections: sedimentology and evolution of a sandy desert system (erg) in the eastern margin of Iberia
Nuevos datos obtenidos en el periodo 2004-2008, indican que las areniscas y arcillas de parte de la “clásica Fm. Escucha” y de la “clásica Fm. Utrillas” constituyen un sistema desértico arenoso (erg) en el que se desarrollaron dunas eólicas crescénticas, interdunas, dunas complejas, draas lineares, sabkhat detríticas, playa lakes y lags de deflación con ventifactos, bajo condiciones climáticas áridas. Este erg presenta un límite proximal (orla de wadis) con el Macizo Ibérico y un límite distal con el Tethys (marine erg-margin system). El cambio climático acaecido en Iberia en el tránsito Aptiense-Albiense, hacia condiciones climáticas áridas, favoreció el desarrollo del sistema desértico arenoso. El descubrimiento del primer sistema desértico cretácico de Europa abre nuevas vías para la comprensión de los procesos paleoclimáticos y paleoceanográficos acaecidos durante el Cretácico Medio.New data obtained in the 2004-2008 period, show that sandstones and mudstones of part of
“the classic Escucha Fm.” and of “the classic Utrillas Fm.” constitute a sandy desert system (erg) in
which crescentic aeolian dunes, interdunes, complex dunes, linear draas, detrital sabkhat, playa lakes
and deflation lags with ventifacts developed under arid climate conditions. This erg system displays a
proximal boundary with the Iberian Massif (wadi belt) and a distal boundary with the Tethys (marine
erg-margin system). The climate change in Iberia in the transit between Aptian-Albian towards arid
climate conditions allowed the development of the sandy desert system. The discovery of the first
Cretaceous erg reported from Europe opens new insights for understanding both palaeoclimate and
palaeogeography during Mid-CretaceousDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
Nitric Oxide And Hypoxia Response In Pluripotent Stem Cells
The expansion of pluripotent cells (ESCs and iPSCs) under conditions that maintain their pluripotency is necessary to implement a cell therapy program. Previously, we have described that low nitric oxide (NO) donor diethylenetriamine/nitric oxide adduct (DETA-NO) added to the culture medium, promote the expansion of these cell types. The molecular mechanisms are not yet known. We present evidences that ESC and iPSCs in normoxia in presence of low NO triggers a similar response to hypoxia, thus maintaining the pluripotency. We have studied the stability of HIF-1α (Hypoxia Inducible Factor) in presence of low NO. Because of the close relationship between hypoxia, metabolism, mitochondrial function and pluripotency we have analyzed by q RT-PCR the expression of genes involved in the glucose metabolism such as: HK2, LDHA and PDK1; besides other HIF-1α target gene. We further analyzed the expression of genes involved in mitochondrial biogenesis such as PGC1α, TFAM and NRF1 and we have observed that low NO maintains the same pattern of expression that in hypoxia. The study of the mitochondrial membrane potential using Mito-Tracker dye showed that NO decrease the mitochondrial function. We will analyze other metabolic parameters, to determinate if low NO regulates mitochondrial function and mimics Hypoxia Response. The knowledge of the role of NO in the Hypoxia Response and the mechanism that helps to maintain self-renewal in pluripotent cells in normoxia, can help to the design of culture media where NO could be optimal for stem cell expansion in the performance of future cell therapies
Periodicidad climática y datación astrocronológica del Grupo Enciso en la cuenca oriental de Cameros (N de España)
This study presents the cyclostratigraphic analysis of a detailed, 1,371 m-thick stratigraphic section logged in the Lower Cretaceous syn-rift lacustrine and alluvial deposits of the Enciso Group, in the eastern Cameros Basin. The spectral analysis of a time series based on lithology reveals periodic sedimentary cycles attributable to variations in the eccentricity of the Earth’s orbit around the Sun (131.8 and 39.9 m-thick sedimentary cycles for the long and short orbital eccentricity cycle) and to changes in the obliquity (12.6 m-thick cycle) and the two precession modes (7.7-5.5 m-thick cycles) of the Earth’s rotation axis. We have constructed a floating astrochronological time scale based on the spectral analysis allowing us to propose that the time interval registered in the studied series is ca. 5.4-5.7 Ma, and to estimate an average sedimentation rate of ~255-239 m/Ma. The presence of cycles representing a similar time span but having different thickness, reveals a higher influence of tectonic activity in the central and upper parts of the succession, and discriminate tectonic from climatic signal, the latter being significant throughout the succession. The sedimentary facies and paleontological content of the studied profile, deposited very close to the coastline, have allowed us to interpret a deepening-shallowing cycle that it is proposed to be eustasy- related (transgressive-regressive cycle). The anchoring of this cycle with the sea level curve in combination with the scarce paleontological dates permit the Enciso Group to be located in the Hauterivian-Barremian, that was approximately deposited between 132.5-126.8 or 132.3-126.9 Ma, depending on whether the short or long eccentricity cycle is considered, respectively
Prevention of diet-induced obesity by apple polyphenols in Wistar rats through regulation of adipocyte gene expression and DNA methylation patterns
This study was conducted to determine the mechanisms implicated in the beneficial effects of apple polyphenols (APs) against diet-induced obesity in Wistar rats, described in a previous study from our group. Supplementation of high-fat sucrose diet with AP prevented adiposity increase by inhibition of adipocyte hypertrophy. Rats supplemented with AP exhibited improved glucose tolerance while adipocytes isolated from these rats showed an enhanced lipolytic response to isoproterenol. AP intake led to reduced Lep, Plin, and sterol regulatory element binding transcription factor 1 (Srebf1) mRNA levels and increased aquaporin 7 (Aqp7), adipocyte enhancer binding protein 1 (Aebp1), and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (Ppargc1a) mRNA levels in epididymal adipocytes. In addition, we found different methylation patterns of Aqp7, Lep, Ppargc1a, and Srebf1 promoters in adipocytes from apple-supplemented rats compared to high-fat sucrose fed rats. The administration of AP protects against body weight gain and fat deposition and improves glucose tolerance in rats. We propose that AP exerts the antiobesity effects through the regulation of genes involved in adipogenesis, lipolysis, and fatty acid oxidation, in a process that could be mediated in part by epigenetic mechanisms
Regulación de la Expresión del Factor de Transcripción Pdx1 por Altas Concentraciones de Óxido Nítrico en Células Madre Embrionarias de Ratón
Estudios previos en nuestro laboratorio muestran que el óxido nítrico a altas concentraciones promueve la diferenciación de células madre embrionarias de ratón (mESC), e induce la expresión de genes de endodermo, entre ellos el factor de transcripción Pdx1, “Pancreas/duodenum homeobox protein 1”. Pdx1, tiene un rol importante en el desarrollo embrionario del páncreas y en la células beta madura. Con el fin de conocer los mecanismos por los que el NO incrementa la expresión de Pdx1, hemos estudiado la región promotora de este gen, encontrando que la expresión de Pdx1 se asocia con la liberación del factor de transcripción Egr1. Además, análisis epigenéticos del promotor muestran que la expresión de Pdx1 va asociada a un cambio en el patrón de metilación de su promotor y a la ocupación de marcas de histonas activadoras (H3Ac y H3K4me3) y a la desocupación de modificadores represores de histonas (HDAC) en el promotor de Pdx1
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