65 research outputs found
Unravelling metabolic mechanisms behind chloroplast desiccation tolerance: chlorophyllous fern spore as a new promising unicellular model
Se sustituye el preprint por el postprint el 23-11-2020Fern spores are unicellular structures produced by the sporophyte generation that give rise to the haploid gametophyte. When released from the sporangium, spores are desiccation tolerant (DT) in the royal fern (Osmunda regalis) and contain fully developed chloroplasts. As a consequence this type of spores are called chlorophyllous spores (CS). Upon transfer to germination conditions, CS initiate a process of imbibition that suppress DT in 72h, before the germination starts. In parallel to such change in DT, thylakoids undergo a profound remodelling in composition and function. Firstly, sustained quenching of chlorophyll fluorescence is relaxed, giving rise to photochemically active CS, while lipid composition shifts from that of a resting structure to a metabolically active cell. Basically trigalactolipids decreased in favour of monogalactolipids, with a parallel desaturation of fatty acids. Storage lipids such as triacylglycerol were quickly depleted. These results highlight the importance of the structure of thylakoids lipid as a key to protect membrane integrity during desiccation, together with the saturation of fatty acids and the constitutive chlorophyll quenching to prevent oxidative damage. The CS used here, in which the same cell shifts from DT to sensitive strategy in 72h, reveal its their potential as unicellular models for future studies on DT.This work was funded by (i) the Basque Government (research project UPV/EHU IT-1018-16; and Predoctoral Fellowship to MLP); (ii) the Spanish Ministry of Economy and Competitiveness (MINECO) and the ERDF (FEDER) (research project CTM2014-53902-C2-2-P, and Juan de la Cierva-Incorporation fellowship IJCI-2014-22489 to BFM)
Vertebrate fauna at the Allosaurus fossil-site of Andrés (Upper Jurassic), Pombal, Portugal
An overview of the faunistic diversity of the Andres fossil-site from the Portuguese Upper Jurassic is presented. This work provides a preliminary approach on the vertebrate fauna known at present. Although this quarry is known since the 1990’s, due to the description on the first robust evidence of a member of the neotetanuran genus Allosaurus outside North America, the results presented here are mainly derived from the analysis of the elements found during the second and third field seasons in 2005. At the moment, among the material collected from Andrés it was identified remains that represent a diverse vertebrate fauna, including fishes, sphenodonts, crocodrylomorphs, pterosaurs, and at least, seven distinct dinosaur forms. The recovery of this diverse and abundant osteological collection from one unique fossil-site is noteworthy for the Upper Jurassic Portuguese record, and only comparable with those from the Guimarota coalmine. Due to these two features plus the good preservation of the fossils, the Andres quarry may be a site of reference for the analysis of vertebrate ecosystems from the Portuguese Upper Jurassic. Dinosaur elements are the most abundant fossils, and among them it is particulary common the presence of remains identified as Allosaurus. These new evidences allow testing the previus phylogenetical hypothesys ascribing the firsts theropod remains from Andrés to A. fragilis, a species described in synchronic levels of the North American Morrison Formation. The similarity between the Allosaurus remains collected in Andres and some specimens from the Morrison Formation seems to point the existence of a genetic flow between some continental vertebrates on both sides of the proto-north Atlantic during the Upper Jurassic. Favourable tectonic conditions for the occurrence of punctual contacts between the two continents is, at present, the best scenario for explain this situation.Se presenta un analisis de la diversidad faunistica del yacimiento de Andrés en el Jurasico Superior de la Cuenca Lusitanica. El presente trabajo pretende establecer un análisis preliminar de la fauna de vertebrados identificada en el yacimiento hasta la fecha. Aunque conocido desde la decada de 1990, debido a la descripcion de la primera evidencia robusta de un neotetanuro del genero Allosaurus fuera de Norteamerica, los resultados presentados derivan principalmente del analisis de elementos encontrados durante la segunda y tercera campanas de excavacion en 2005. Hasta el momento han sido identificados entre el material recogido en Andrés, representantes de diversos taxones de vertebrados que incluyen que incluyen peces, esfenodontos, crocodilomorfos, pterosaurios y, al menos, siete formas distintas de dinosaurios. La presencia de esta diversidad y abundancia de restos osteologicos en el mismo yacimiento representa una situacion unica en el registro del Jurasico Superior portugues, tan solo comparable a la del yacimiento clasico de la mina de carbon de Guimarota. Atendiendo a estas dos caracteristicas y a la buena preservacion de los fosiles, el yacimiento de Andres puede ser considerado como una localidad de referencia para el estudio de los ecosistemas con vertebrados del Jurasico Superior portugues. Los restos de dinosaurios son los fosiles mas abundantes y, entre ellos, son particularmente comunes los asignables a Allosaurus. Estas nuevas evidencias proporcionan a A. fragilis, una especie descrita en niveles sincronicos de la Formacion Morrison en Norteamerica. La similitud entre los restos de Allosaurus recogidos en Andres y algunos de los ejemplares de la Formacion Morrison, sugiere la existencia de un flujo genético entre algunos vertebrados continentales de ambos lados del proto-Atlántico norte durante el Jurásico Superior. La existencia de condiciones tectonicas favorables para la existencia de contactos puntuales entre los dos continentes es actualmente el mejor escenario para explicar esta situacion
Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition
Ramalina farinacea is an epiphytic fruticose lichen that is relatively abundant in areas with Mediterranean, subtropical or temperate climates. Little is known about photobiont diversity in different lichen populations. The present study examines the phycobiont composition of several geographically distant populations of R. farinacea from the Iberian Peninsula, Canary Islands and California as well as the physiological performance of isolated phycobionts. Based on anatomical observations and molecular analyses, the coexistence of two different taxa of Trebouxia (working names, TR1 and TR9) was determined within each thallus of R. farinacea in all of the analysed populations. Examination of the effects of temperature and light on growth and photosynthesis indicated a superior performance of TR9 under relatively high temperatures and irradiances while TR1 thrived at moderate temperature and irradiance. Ramalina farinacea thalli apparently represent a specific and selective form of symbiotic association involving the same two Trebouxia phycobionts. Strict preservation of this pattern of algal coexistence is likely favoured by the different and probably complementary ecophysiological responses of each phycobiont, thus facilitating the proliferation of this lichen in a wide range of habitats and geographic areas. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.This study was funded by the Spanish Ministry of Education and Science (CGL2006-12917-C02-01/02), the Spanish Ministry of Science and Innovation (CGL2009-13429-C02-01/02), the AECID (PCI_A/024755/09) and the Generalitat Valenciana (PROMETEO 174/2008 GVA). We are grateful to Dr J. Gimeno-Romeu (University of California, Davis, USA) and to Dr P. J. G. de Nova (IREC, Ciudad Real, Spain), who were the first to isolate DNA from Ramalina farinacea thalli in our group. 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Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers
[EN] The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multicavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability.We thank Prof. Jose Capmany for the thoughtful discussions and recommendations that greatly contribute to this work. This research was supported by the Spanish MINECO Projects TEC2014-60378-C2-1-R and TEC2015-62520-ERC, the Valencian Research Excellency Award Program GVA PROMETEO 2013/012, the Spanish MECD FPU Scholarship (FPU13/04675) for J. Hervas, and the Spanish MINECO Ramon y Cajal Program (RYC-2014-16247) for I. Gasulla.Gasulla Mestre, I.; Barrera Vilar, D.; Hervás-Peralta, J.; Sales Maicas, S. (2017). 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A predictive model and risk factors for case fatality of covid-19
This study aimed to create an individualized analysis model of the risk of intensive care unit (ICU) admission or death for coronavirus disease 2019 (COVID-19) patients as a tool for the rapid clinical management of hospitalized patients in order to achieve a resilience of medical resources. This is an observational, analytical, retrospective cohort study with longitudinal follow-up. Data were collected from the medical records of 3489 patients diagnosed with COVID-19 using RT-qPCR in the period of highest community transmission recorded in Europe to date: February–June 2020. The study was carried out in in two health areas of hospital care in the Madrid region: the central area of the Madrid capital (Hospitales de Madrid del Grupo HM Hospitales (CH-HM), n = 1931) and the metropolitan area of Madrid (Hospital Universitario Príncipe de Asturias (MH-HUPA) n = 1558). By using a regression model, we observed how the different patient variables had unequal importance. Among all the analyzed variables, basal oxygen saturation was found to have the highest relative importance with a value of 20.3%, followed by age (17.7%), lymphocyte/leukocyte ratio (14.4%), CRP value (12.5%), comorbidities (12.5%), and leukocyte count (8.9%). Three levels of risk of ICU/death were established: low-risk level (20%). At the high-risk level, 13% needed ICU admission, 29% died, and 37% had an ICU–death outcome. This predictive model allowed us to individualize the risk for worse outcome for hospitalized patients affected by COVID-19
A Predictive Model and Risk Factors for Case Fatality of COVID-19
This study aimed to create an individualized analysis model of the risk of intensive care unit (ICU) admission or death for coronavirus disease 2019 (COVID-19) patients as a tool for the rapid clinical management of hospitalized patients in order to achieve a resilience of medical resources. This is an observational, analytical, retrospective cohort study with longitudinal follow-up. Data were collected from the medical records of 3489 patients diagnosed with COVID-19 using RT-qPCR in the period of highest community transmission recorded in Europe to date: February-June 2020. The study was carried out in in two health areas of hospital care in the Madrid region: the central area of the Madrid capital (Hospitales de Madrid del Grupo HM Hospitales (CH-HM), n = 1931) and the metropolitan area of Madrid (Hospital Universitario Príncipe de Asturias (MH-HUPA) n = 1558). By using a regression model, we observed how the different patient variables had unequal importance. Among all the analyzed variables, basal oxygen saturation was found to have the highest relative importance with a value of 20.3%, followed by age (17.7%), lymphocyte/leukocyte ratio (14.4%), CRP value (12.5%), comorbidities (12.5%), and leukocyte count (8.9%). Three levels of risk of ICU/death were established: low-risk level (20%). At the high-risk level, 13% needed ICU admission, 29% died, and 37% had an ICU-death outcome. This predictive model allowed us to individualize the risk for worse outcome for hospitalized patients affected by COVID-19
Lichen rehydration in heavy metal polluted environments: Pb modulates the oxidative response of both Ramalina farinacea thalli and its isolated microalgae
Lichens are adapted to desiccation/rehydration and accumulate heavy metals, which induce ROS especially from the photobiont photosynthetic pigments. Although their mechanisms of abiotic stress tolerance are still to be unravelled, they seem related to symbionts' reciprocal upregulation of antioxidant systems. With the aim to study the effect of Pb on oxidative status during rehydration, the kinetics of intracellular ROS, lipid peroxidation and chlorophyll autofluorescence of whole Ramalina farinacea thalli and its isolated microalgae (Trebouxia TR1 and T. TR9) was recorded. A genetic characterization of the microalgae present in the thalli used was also carried out in order to assess possible correlations among the relative abundance of each phycobiont, their individual physiological responses and that of the entire thallus. Unexpectedly, Pb decreased ROS and lipid peroxidation in thalli and its phycobionts, associated with a lower chlorophyll autofluorescence. Each phycobiont showed a particular pattern, but the oxidative response of the thallus paralleled the TR1's, agreeing with the genetic identification of this strain as the predominant phycobiont. We conclude that: (1) the lichen oxidative behaviour seems to be modulated by the predominant phycobiont and (2) Pb evokes in R. farinacea and its phycobionts strong mechanisms to neutralize its own oxidant effects along with those of rehydration
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