662 research outputs found

    Resolving taxonomic problems through cuticular analysis in Early Cretaceous bennettitalean leaves from Patagonia

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    The genus Ptilophyllum Morris is one of the most common bennettitalean leaf genera found in the Cretaceous megafloras from Western Gondwana, particularly Patagonia and Antarctica. Among several specimens, the similarity in the morphology of their leaves make them hard to distinguish from each other, which usually leads to misinterpretations. Therefore, the study of the epidermal features in this taxon is essential, especially because the occurrence of papillae, its size, forms, and distributions are relevant for the differentiation of species. Based on these considerations, the erection of a new Ptilophyllum species here indicated that the papillae are a key character to resolve taxonomic conflict between some of the Cretaceous taxa from Western Gondwana. Ptilophyllum eminelidarum sp. nov. Carrizo, Lafuente Diaz et Del Fueyo, was recovered from the Springhill Formation at the Río Correntoso and Estancia El Salitral localities, Santa Cruz province, Argentina. Epidermal foliar features are fully described with the aid of light and electron (SEM and TEM) microscopy. This new bennettitalean species is characterized by pinnate leaves with an epidermis bearing two distinct, uniformly distributed, papillae morphologies: the compound papillae are situated on the vein cells, and the small simple papillae are located between veins. The cuticular membrane ultrastructure consists of three layers corresponding to the cuticle proper (A2) with fibrillar aspect and the cuticular layers B1 and B2 with homogeneous-granular and fibrillar-granular aspect, respectively. This combination of features are unique to this species, differentiating it from other coetanean species of the genus from Western Gondwana. This finding complements and reinforces previous knowledge regarding the megaflora of the Springhill Formation and underscores the important role of the Bennettitales within the plant associations during the Cretaceous of Patagonia.Fil: Carrizo, Martin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

    Cuticle ultrastructure in Brachyphyllum garciarum sp. nov (Lower Cretaceous, Argentina) reveals its araucarian affinity

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    A detailed and extensive study of a new species, Brachyphyllum garciarum sp. nov., was carried out through the analysis of the gross morphology and the cuticle fine details, structure and ultrastructure characters of its leaves using light microscope and scanning and transmission electron microscope. The fossils consist of compressions of incomplete twigs with well-preserved cuticle, collected from pelitic levels of the Springhill Formation (lower Hauterivian/lower Barremian) at the Río Correntoso locality in the Santa Cruz province, Argentina. The twigs have adpressed scale-like leaves spirally disposed. Leaves have a rhomboidal to pyramidal shape, a width and length always in a 1:1 ratio, margin entire and apex mostly rounded. Leaves are amphistomatic with stomatal apparatuses occurring in groups of narrow-wedge shape along the leaf axis. Stomatal apparatuses are close to each other with subsidiary cells in contact; the guard cells are sunken, with marked polar extensions and thickened mouth. Remnants of hypodermis cells are present in both foliar epidermis. Ultrastructurally, four types of cuticles were observed and evaluated statistically in detail: the ordinary epidermal cell upper and lower cuticles and the subsidiary cell cuticle are compounded of A2 granular layer and a spongy B1 layer somewhat mixed with cell wall remnants, while the guard cell cuticle presents only a spongy B1 layer. An Energy Dispersive Spectroscopy study was also made revealing the presence of 10 characteristic ratios with taxonomic importance, at least at the species level: N/Na, S/Cl, S/Na, Cl/K, K/Na as the most important; followed by N/Ca, S/K, Cl/Ca, Cl/Na; and S/Ca being the least reliable. The combination of morphological and cuticle ultrastructure features of Brachyphyllum garciarum sp. nov. are unique and clearly different from other contemporary species of the genus from Western Gondwana. Moreover, the ultrastructure of the foliar cuticle suggests a highly probable affinity with the Araucariaceae Family, more precisely with the genus Araucaria. Of the four recognized sections among the living species of Araucaria, the leaf morphology of B. garciarum sp. nov. is mostly similar with some species of the Eutacta section.Fil: Carrizo, Martin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Guignard, Gaëtan. Université Claude Bernard Lyon 1; Francia. Centre National de la Recherche Scientifique; Franci

    Permineralized conifer-like leaves from the jurassic of patagonia (Argentina) and its paleoenvironmental implications

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    Anatomically preserved conifer-like leaves from the Middle Jurassic La Matilde Formation at the Barda Blanca locality in the Gran Bajo de San Julián area, southern Patagonia are described here. Leaves are assigned to conifers based on the following foliar features: thick-walled epidermal cells, a sclerenchymatic hypodermis, resin canals and transfusion tracheids associated with the vascular bundle. General mesophyll anatomy and inferred foliar morphology suggest a similarity to large, broad, linearlanceolate, multi-veined conifer-like leaves. The general foliar habit indicates an affinity with the large, multi-veined leaves of the Araucariaceae; especially with those exhibited by the species of the Araucaria sections, Araucaria and Bunya. Anatomically, the permineralized leaves exhibit xeromorphic foliar features, including thick-walled epidermal cells, an isobilateral mesophyll with well-developed palisade cells and mechanical tissue. The general leaf anatomy shown by the Patagonian specimens along with sedimentological data may suggest that during the deposition of the La Matilde Formation at the Barda Blanca locality, the parent plant was well adapted to the environmental conditions, which probably consisted of a high light intensity with an adequate quantity of water in the soil, which increased the maximum leaf conductance of CO2.Fil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Gnaedinger, Silvia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Carrizo, Martín Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

    Recurrent volcanic activity recorded in araucarian wood from the Lower Cretaceous Springhill Formation, Patagonia, Argentina: Palaeoenvironmental interpretations

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    This paper describes a petrified trunk collected from a conglomerate bed of the Springhill Formation (Berriasian?Valanginian) in the Estancia El Álamo locality, Santa Cruz Province, Argentina. The fossil trunk is classified within the ubiquitous genus Agathoxylon and the wood anatomy shows a close affinity to that of Araucariaceae. This Patagonian wood has a distinct combination of anatomical characteristics unique among all known species from the Jurassic and Cretaceous of Western Gondwana allowing to diagnose a new fossil taxon Agathoxylon mendezii sp. nov. Sedimentological and megafloristic proxies of the Springhill Formation suggest that Agathoxylon mendezii sp. nov. grew under a warm and wet climate, which indicates a subtropical to temperate palaeoenvironment. However, the large number of frost rings in the earlywood of this araucarian tree suggests that the palaeoenvironment at Estancia El Álamo was subjected to recurrent disturbances, most likely caused by regional continuous volcanic activity originating from volcanoes located far away to the west. This activity would have produced periodic stratospheric veils that promoted rapid decreases in surface air temperature; the wood response to such stressful conditions would have been the formation of numerous (at least five) frost rings. Although recurrent eruptions in Patagonia during the Early Cretaceous are well recorded, this study is the first to register eruptions recorded in a coniferous wood.Fil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Carrizo, Martin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

    Fossilization model for squamastrobus tigrensis foliage in a volcanic-Ash deposit: Implications for preservation and taphonomy (podocarpaceae, lower cretaceous, Argentina)

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    The present study is a holistic approach to the relationship between volcaniclastic host rock characteristics and the fossilization processes of short leafy coniferous branches of Squamastrobus tigrensis, preserved as fossilized-cuticles (Lower Cretaceous, Baqueró Group, Patagonia, Argentina). The question of diagenetic influences of Aptian volcaniclastic sedimentation on preservation chemistry and taphonomic processes is addressed. Whereas infrared spectroscopy provided chemical information on the leaves, vitrinite reflectance and complementary thermal indicators provided data on the thermal maturity of the dispersed organic matter in the host rock. Three sample types were analyzed: Fossilized-cuticle, macerated fossilized-cuticle (by infrared spectroscopy), and associated organic host rock matter (by light microscopy). Results clearly show chemical variability between, and within the fossilized-cuticle and cuticle, as well as a similarity to type I/II kerogen, i.e., high contents of both aliphatic groups and oxygencontaining compounds. Combined with the lower maturity of the host rock, the importance of the depositional environment during burial and taphonomic conditions that affected the fossilization of S. tigrensis are summarized in a general fossilization model.Fil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: D`angelo, José Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Cape Breton University; CanadáFil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Zodrow, Erwin L.. Cape Breton University; Canad

    Identification of the Immunological Changes Appearing in the CSF During the Early Immunosenescence Process Occurring in Multiple Sclerosis

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    Immunitat adaptativa; Envelliment; Esclerosi múltipleInmunidad adaptativa; Envejecimiento; Esclerosis múltipleAdaptive immunity; Aging; Multiple sclerosisPatients with multiple sclerosis (MS) suffer with age an early immunosenescence process, which influence the treatment response and increase the risk of infections. We explored whether lipid-specific oligoclonal IgM bands (LS-OCMB) associated with highly inflammatory MS modify the immunological profile induced by age in MS. This cross-sectional study included 263 MS patients who were classified according to the presence (M+, n=72) and absence (M-, n=191) of LS-OCMB. CSF cellular subsets and molecules implicated in immunosenescence were explored. In M- patients, aging induced remarkable decreases in absolute CSF counts of CD4+ and CD8+ T lymphocytes, including Th1 and Th17 cells, and of B cells, including those secreting TNF-alpha. It also increased serum anti-CMV IgG antibody titers (indicative of immunosenescence) and CSF CHI3L1 levels (related to astrocyte activation). In contrast, M+ patients showed an age-associated increase of TIM-3 (a biomarker of T cell exhaustion) and increased values of CHI3L1, independently of age. Finally, in both groups, age induced an increase in CSF levels of PD-L1 (an inductor of T cell tolerance) and activin A (part of the senescence-associated secretome and related to inflammaging). These changes were independent of the disease duration. Finally, this resulted in augmented disability. In summary, all MS patients experience with age a modest induction of T-cell tolerance and an activation of the innate immunity, resulting in increased disability. Additionally, M- patients show clear decreases in CSF lymphocyte numbers, which could increase the risk of infections. Thus, age and immunological status are important for tailoring effective therapies in MS.This work was supported by grants FIS-PI15/00513, FIS-PI18/00572 and RD16/0015/0001 from the Instituto de Salud Carlos III. Ministerio de Ciencia e Innovación, Spain and FEDER: "Una manera de hacer Europa"

    Reproductive system and floral biology of Lantana camara (Verbenaceae) in a riparian population of the Río de la Plata

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    Introducción y objetivos: La biología floral de Lantana camara L., nativa del Centro y Sur de América e invasora cosmopolita, tiene aspectos desconocidos y controvertidos. El objetivo de este trabajo fue determinar el sistema reproductivo, atributos florales y polinizadores en una población ribereña del Río de la Plata.M&M: Se emplearon los métodos usuales de la biología de la polinización. El estudio se realizó en Ciudad Universitaria, Ciudad Autónoma de Buenos Aires, Argentina, en la primavera de 2012.Resultados: Las flores emiten olor leve y dulce mediante osmóforos que rodeanla entrada del tubo floral, coincidiendo con el patrón de absorción-reflexión en el espectro UV. El néctar se acumula en el tubo corolino, secretado probablemente por tricomas situados en la base. Durante la antesis, se suceden tres fases florales, distinguibles por cambios en la coloración de la corola, intensidad del aroma, cantidad de recompensa y madurez de las anteras y el estigma. Las flores, psicófilas, recibieron visitas de lepidópteros diurnos, y también de himenópteros, dípteros y colibríes. El mayor éxito reproductivo ocurrió con polinización libre; los índices de autocompatibilidad y P/O indicaron autocompatibilidad parcial y xenogamia facultativa, respectivamente.Conclusiones: L. camara se autopoliniza espontáneamente, probablemente unacausa de su propagación global. Debido a su actividad en las flores, fase floralvisitada, carga polínica y frecuencia de visitas sólo las mariposas Agraulis vanillae maculosa, Dryas iullia alcionea y Cymaenes sp. polinizarían en este sitio.Background and aims: The floral biology of Lantana camara, a native species of Central and South America and invasive cosmopolitan, still presents poorly-known and controversial aspects. The aim of this work was to determine the reproductive system, floral attributes and pollinators in a coastal population of Río de la Plata. M&M: The usual methods in pollination biology were employed. The study was performed in Ciudad Universitaria, Ciudad Autónoma de Buenos Aires, Argentina, during the spring of 2012. Results: The flowers emit mild and sweet odor by osmophores arranged around the floral tube entrance, in coincidence with the absorption-reflection pattern in the UV spectrum. Nectar accumulates in the floral tube, probably secreted by trichomes situated at the petals base. During anthesis, three floral phases succeed, distinguished by changes in corolla coloration, aroma intensity, reward quantity and anther and stigma maturity. The psychophilous flowers were visited by diurnal lepidopterans and by hymenopterans, dipterans and hummingbirds. The highest reproductive success occurred with free pollination; the self-incompatibility and P/O indexes showed partial self-compatibility and facultative xenogamy, respectively. Conclusions: L. camara is capable of successful spontaneous self-pollination, probably one reason of its global spread. Due to their activity on the flowers, visited floral phase, pollen load and frequency of visits, only the butterflies Agraulis vanillae maculosa, Dryas iullia alcionea and Cymaenes sp. would pollinate in this site.Fil: Amela Garcia, Maria Teresa. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Aquino, Diego Sebastián. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bouza, Agustina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; ArgentinaFil: Grohar, Mariana Cecilia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Herrera Cano, Anahí Naymé. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Lafuente Diaz, Maiten Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; ArgentinaFil: Miguez, María Belén. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Scorza, María Victoria. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Chamer, Ana Marina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología Reproductiva y Sistematica Experimental En Plantas Vasculares; Argentin

    Satisfaction survey with DNA cards method to collect genetic samples for pharmacogenetics studies

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    BACKGROUND: Pharmacogenetic studies are essential in understanding the interindividual variability of drug responses. DNA sample collection for genotyping is a critical step in genetic studies. A method using dried blood samples from finger-puncture, collected on DNA-cards, has been described as an alternative to the usual venepuncture technique. The purpose of this study is to evaluate the implementation of the DNA cards method in a multicentre clinical trial, and to assess the degree of investigators' satisfaction and the acceptance of the patients perceived by the investigators. METHODS: Blood samples were collected on DNA-cards. The quality and quantity of DNA recovered were analyzed. Investigators were questioned regarding their general interest, previous experience, safety issues, preferences and perceived patient satisfaction. RESULTS: 151 patients' blood samples were collected. Genotyping of GST polymorphisms was achieved in all samples (100%). 28 investigators completed the survey. Investigators perceived patient satisfaction as very good (60.7%) or good (39.3%), without reluctance to finger puncture. Investigators preferred this method, which was considered safer and better than the usual methods. All investigators would recommend using it in future genetic studies. CONCLUSION: Within the clinical trial setting, the DNA-cards method was very well accepted by investigators and patients (in perception of investigators), and was preferred to conventional methods due to its ease of use and safety
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