220 research outputs found

    Species Identification of Food Spoilage and Pathogenic Bacteria by MALDI-TOF Mass Fingerprinting

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    18 pages, 1 table, 2 figuresFood quality and safety is an increasingly important public health issue. Nowadays, the topics “food quality” and “food safety” are very close and two important issues in the food sector, due to the globalization of the food supply and the increased complexity of the food chain. The consumers need to purchase safe products that do not involve any kind of risk for health. On one hand, the aim of the “food safety” is to avoid health hazards for the consumer: microbiological hazards, pesticide residues, misuse of food additives and contaminants, such as chemicals, biological toxins and adulteration. On the other hand, “food quality” includes all attributes that influence the value of a product for the consumer; this includes negative attributes such as spoilage, contamination with filth, discoloration, off-odors and positive attributes such as the origin, color, flavor, texture and processing method of the food (FAO, 2003)This work was funded by project 10PXIB261045PR from Xunta de Galicia and by project AGL2010-19646 from the Spanish Ministry of Science and Technology. The work of K. Böhme and I.C. Fernández-No is supported by a “Maria Barbeito” and “Lucas Labrada” research contract from Xunta de GaliciaN

    Nuevos datos cronoestratigráficos de la Fm. Marismas (Bajo Guadalquivir)

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    La Formación Marismas forma la parte superior del relleno sedimentario del sector SW de la cuenca del Guadalquivir. Los datos previos sobre el sondeo Lebrija, indicaban que la parte más alta de esta formación tenía edades de hasta 9.6 kyr BP y en la parte inferior eran cercanas o fuera del rango del radiocarbono, pero posterior a la reversión Brunhes-Matuyama. En este trabajo se aportan 17 nuevas dataciones realizadas mediante racemización de aminoácidos en valvas de ostrácodos en este mismo sondeo, con el fin de completar la cronología y el modelo de edad de la parte superior e inferior de la Fm Marismas. El resultado indica que el tramo situado por debajo del metro 56, arroja edades que oscilan entre 164685±14110 y 202830±30255, que se correlacionan con los estadios isotópicos marinos MIS 6-7 del Pleistoceno medio, edad sensiblemente más baja a las inferidas para esta formación en otros puntos de la Cuenca del bajo GuadalquivirEste trabajo se ha realizado dentro del proyecto Guadaltyc (Impacto del clima y la tectónica en el registro sedimentario de la Cuenca del Guadalquivir, (CGL2012-30875).Peer Reviewe

    Unidades litológicas del Neógeno en el extremo oeste de la Cuenca del Guadalquivir y su correlación con el sondeo Huelva-1 (Huelva - España)

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    A detailed surveying and a new geological map of the sheet at 1:50.000 number 999/1016 (Huelva - Los Caños), located at the west end of the Guadalquivir Basin, has been carried out. This data allows us to propose a new organization of the lithological units present at the west side of the Odiel River. These units include all the sedimentary record in this sector of the Guadalquivir Basin, ranging from Tortonian to Pliocene, but with shallower and coarser facies that are only present in this part of the basin. This fact is due to the location of the area, probably less subsiding due to a longer distance from Betic-Rif orogen. The lithological units are described concisely and a correlation with the core of the Huelva-1 borehole and with the outcrops of Huelva – Palos de la Frontera area is also proposed. The units are organized in a stack of sequences with a progradational pattern, typical of a basin margin, and highlighting a gradual reduction of the accommodation space in the late Messinian and during the Pliocene.Se ha realizado un reconocimiento detallado y un nuevo mapa geológico de la hoja a 1: 50.000 número 999/1016 (Huelva - Los Caños), situada en el extremo oeste de la Cuenca del Guadalquivir. Estos datos nos han permitido proponer una nueva organización de las unidades litológicas presentes en el lado oeste del río Odiel. Estas unidades incluyen el registro sedimentario completo de este sector de la Cuenca del Guadalquivir, que va desde Tortoniense al Plioceno, pero mostrando unas facies más someras y gruesas que solo están presentes en esta parte de la cuenca. Este hecho se debe a la ubicación de la zona, probablemente menos subsidente debido a su mayor distancia con respecto al orógeno Bético-Rifeño. Las unidades litológicas se describen de forma concisa y se propone también su correlación con el testigo del sondeo Huelva-1 y los afloramientos de la zona de Huelva - Palos de la Frontera. Las unidades litológicas se organizan formando un apilamiento de secuencias con un patrón progradacional, típico de un borde de cuenca, y ponen de manifiesto una reducción gradual del espacio de acomodación a finales del Messiniense y durante el Plioceno.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)Plan de Edición de Cartografía Geológica y Geomorfológica del IGME 2013-2016pu

    Paleomagnetic and paleoenvironmental implications of magnetofossil occurrences in late Miocene marine sediments from the Guadalquivir Basin, SW Spain.

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    Although recent studies have revealed more widespread occurrences of magnetofossils in pre-Quaternary sediments than have been previously reported, their significance for paleomagnetic and paleoenvironmental studies is not fully understood. We present a paleo- and rock-magnetic study of late Miocene marine sediments recovered from the Guadalquivir Basin (SW Spain). Well-defined paleomagnetic directions provide a robust magnetostratigraphic chronology for the two studied sediment cores. Rock magnetic results indicate the dominance of intact magnetosome chains throughout the studied sediments. These results provide a link between the highest-quality paleomagnetic directions and higher magnetofossil abundances. We interpret that bacterial magnetite formed in the surface sediment mixed layer and that these magnetic particles gave rise to a paleomagnetic signal in the same way as detrital grains. They, therefore, carry a magnetization that is essentially identical to a post-depositional remanent magnetization, which we term a bio-depositional remanent magnetization. Some studied polarity reversals record paleomagnetic directions with an apparent 60-70 kyr recording delay. Magnetofossils in these cases are interpreted to carry a biogeochemical remanent magnetization that is locked in at greater depth in the sediment column. A sharp decrease in magnetofossil abundance toward the middle of the studied boreholes coincides broadly with a major rise in sediment accumulation rates near the onset of the Messinian salinity crisis (MSC), an event caused by interruption of the connection between the Mediterranean Sea and the Atlantic Ocean. This correlation appears to have resulted from dilution of magnetofossils by enhanced terrigenous inputs that were driven, in turn, by sedimentary changes triggered in the basin at the onset of the MSC. Our results highlight the importance of magnetofossils as carriers of high-quality paleomagnetic and paleoenvironmental signals even in dominantly terrigenous sediments

    Late Holocene climate variability in the southwestern Mediterranean region: an integrated marine and terrestrial geochemical approach

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    10 páginas, 5 figuras, 1 tabla.A combination of marine (Alboran Sea cores, ODP 976 and TTR 300 G) and terrestrial (Zoñar Lake, Andalucia, Spain) geochemical proxies provides a high-resolution reconstruction of climate variability and human influence in the southwestern Mediterranean region for the last 4000 years at inter-centennial resolution. Proxies respond to changes in precipitation rather than temperature alone. Our combined terrestrial and marine archive documents a succession of dry and wet periods coherent with the North Atlantic climate signal. A dry period occurred prior to 2.7 cal ka BP – synchronously to the global aridity crisis of the third-millennium BC – and during the Medieval Climate Anomaly (1.4–0.7 cal ka BP). Wetter conditions prevailed from 2.7 to 1.4 cal ka BP. Hydrological signatures during the Little Ice Age are highly variable but consistent with more humidity than the Medieval Climate Anomaly. Additionally, Pb anomalies in sediments at the end of the Bronze Age suggest anthropogenic pollution earlier than the Roman Empire development in the Iberian Peninsula. The Late Holocene climate evolution of the in the study area confirms the see-saw pattern between the eastern and western Mediterranean regions and the higher influence of the North Atlantic dynamics in the western Mediterranean.Projects LIMNOCLIBER REN 2003-09130- C02-02, CALIBRE CGL 2006-13327-c04/CLI, CGL-2006-2956- BOS, CGL2009-07603 (MICINN), 200800050084447 (MARM) and RNM 05212 (Junta de Andalucía), we also thanks Projects GRACCIE (CSD2007- 00067) and CTM2009-07715 (MICINN), Research Group 0179 (Junta de Andalucía) and the Training- Through-Research Programme.Peer reviewe

    The influence of subaquatic springs in lacustrine sedimentation: Origin and paleoenvironmental significance of homogenites in karstic Lake Banyoles (NE Spain)

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    Banyoles (42°08′N, 2°45′E) is the largest and deepest lake of karstictectonic origin in the Iberian Peninsula. The lake comprises two basins and six sub-circularly shaped sub-basins fed by subaquatic springs. Periods of intense groundwater inflow in the deepest sub-basins lead to the fluidization and re-suspension of previously deposited sediments and subsequent settling forming homogenite deposits on the southern basin intermediate platforms. The multiproxy analysis of sediment cores combined with high resolution seismic stratigraphy (3.5 kHz pinger and multi-frequency Chirp surveys) allows a precise reconstruction of depositional environments and related hydrological variability and groundwater inflowduring the last ca. 7.6 cal kyr BP. According to the agemodel based on 137Cs, 210Pb and AMS 14C dating, homogenite deposition occurred between 7.2 and 5.5 cal kyr BP, stopped during the middle Holocene (5.52.8 cal kyr BP) and greatly increased during the last two millennia with a total of 17 homogenite layers individually up to 75 cm-thick. The onset of this unique sedimentation mode at ca. 3 cal kyr BP coincides with an increase in lake level, evidenced by the onlapping of fine-grained, distal sediments over coarser massive, carbonate-rich, littoral deposits. A detailed, multidisciplinary study of the homogenites (sedimentology, physical properties, high-resolution elemental geochemistry, mineral composition, grain-size, organic matter content and SEM) combined with seismic stratigraphy demonstrates that the fluidization events triggering the formation of the homogenites were caused by higher and more intense local groundwater inflow, related to increased rainfall during the Late Holocene and likely intensified by land use changes during the last millennium

    Hydrogeochemical characteristics of the Saliencia lakes (Somiedo Natural Park, NW Spain): trophic state and relationship with anthropogenic pressures

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    The high-mountain lakes of Saliencia (El Valle, La Cueva, Calabazosa and Cerveriz), in the Somiedo Natural Park (Asturias, NW Spain), have been subject to different anthropogenic pressures, including metal mining, cattle grazing, damming activities and water channelling work for hydroelectric exploitation. This paper reports the results of a recent geochemical and limnological study conducted in these lakes, for which no previous study existed in the literature. Based on depth profiles of temperature, conductivity, pH and ORP, as well as dissolved oxygen, chlorophyll-a, organic carbon, nutrient and metal concentration, we discuss the impact of anthropogenic pressure on the lakes. In the sampling period (July to September, 2014-2016), most of the lakes showed a marked stratification with vertical gradients as a result of different physical and (bio)geochemical processes. All the lakes showed a good environmental state with no apparent metal pollution. However, this set of mountain lakes is not homogeneous with regard to nutrient availability, primary productivity, or hypolimnetic oxygen deficit and a range of trophic conditions exist from oligotrophic (El Valle) to eutrophic (Calabazosa). This trend shows a good correlation with total phosphorus concentration (e.g., 10 µg/L P in El Valle vs. 35 µg/L P in Calabazosa), though erosive processes in the catchment may also have contributed to increase the oxygen consumption rate through an import of allochthonous organic matter. Higher nitrate contents seem to characterize the areas with higher grazing pressure (e.g., El Valle), though the obtained data do not allow us to establish any evident relationship between cattle activity and eutrophication

    Dendronized Anionic Gold Nanoparticles: Synthesis, Characterization and Antiviral Activity

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    Anionic carbosilane dendrons decorated with sulfonate functions and with a thiol moiety at the focal point have been used to synthesize water soluble gold nanoparticles (AuNPs) by direct reaction of dendrons, gold precursor and reducing agent in water and also by place-exchange reaction. These nanoparticles have been characterized by nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV, elemental analysis, and Z potential. Also, the interacting ability of the anionic sulfonate functions was investigated by electron paramagnetic resonance (EPR) using copper(II) as a probe. It was found that the different structures and conformations of the AuNPs modulate the availability of sulfonate and thiol groups to be complexed by copper(II). Toxicity assays of AuNPs showed that those produced by direct reaction were less toxic than those obtained by ligand exchange. Inhibition of HIV-1 infection was higher for dendronized AuNPs than for dendrons.Ministerio de Economía y EmpresaComunidad de MadridUniversidad de Alcal

    Role of the human concentrative nucleoside transporter (hCNT1) in the cytotoxic action of 5[Prime]-deoxy-5-fluorouridine, an active intermediate metabolite of capecitabine, a novel oral anticancer drug.

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    We attempt to identify the plasma membrane transporter involved in the uptake of 5'-deoxy-5-fluorouridine (5'-DFUR), an intermediate metabolite of capecitabine. This novel oral fluoropyrimidine is used in cancer treatments and is a direct precursor of the cytostatic agent 5'-fluorouracil. We also examine the role of the transporter in 5'-DFUR cytotoxicity. The human concentrative nucleoside transporter (hCNT1) was cloned from human fetal liver and expressed in Xenopus laevis oocytes. The two-electrode voltage-clamp technique was used to demonstrate that 5'-DFUR, but not capecitabine or 5'-FU, is an hCNT1 substrate. Then, hCNT1 was heterologously expressed in the mammalian cell line Chinese hamster ovary-K1. Functional expression was demonstrated by monitoring transport of radiolabeled substrates and by using a monospecific polyclonal antibody generated against the transporter. hCNT1-expressing cells were more sensitive to 5'-DFUR than vector-transfected or wild-type cells. The sensitivity of the three cell types to other agents such as cisplatin or 5'-FU was identical. In conclusion, this study shows that 1) the pharmacological profile of a nucleoside transporter can be determined by an electrophysiological approach; 2) the hCNT1 transporter is involved in 5'-DFUR uptake; and 3) hCNT1 expression may increase cell sensitivity to 5'-DFUR treatment. This study also reports for the first time the generation of an antibody against hCNT1, which may be useful in the elucidation of the relationship between hCNT1 expression and tumor response to capecitabine treatmen
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