2,126 research outputs found

    Dominant BIN1-related centronuclear myopathy (CNM) revealed by lower limb myalgia and moderate CK elevation

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    We report a BIN1-related CNM family with unusual clinical phenotype. The proband, a 56-year-old man suffered of lower limbs myalgia since the age of 52. Clinical examination showed short stature, mild symmetric eyelid ptosis without ophthalmoplegia, scapular winging and Achilles tendon retraction. A muscle weakness was not noted. CK levels were up to 350 UI/L. Deltoid muscle biopsy showed nuclear centralization and clustering, deep sarcolemmal invaginations and type 1 fiber hypotrophy. Whole body MRI revealed fatty infiltration of posterior legs compartments, lumbar paraspinal and serratus muscles. Myotonic dystrophy type1 and 2, Pompe disease and MTM1 and DNM2-related CNM were ruled out. By sequencing BIN1, we identified a heterozygous pathogenic mutation [c.107C > A (p.A36E)], and we demonstrate that the mutation strongly impairs the membrane tubulation property of the protein. One affected sister carried the same mutation. Her clinical examination and muscle MRI revealed a similar phenotype. Our findings expand the clinical and genetic spectrum of the autosomal dominant CNM associated with BIN1 mutations

    Can the parasites of the head of juvenile Thunnus thynnus help to identify its nursery areas in the Mediterranean Sea?

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    Between 2009 and 2013, the head region of 102 juveniles of Atlantic bluefin tuna (Thunnus thynnus L.) caught in four nursery areas of the Mediterranean Sea (Balearic Sea, Ionian Sea, Ligurian Sea and Tyrrhenian Sea) were analysed for parasites. Eleven parasite species were found: Capsala magronum, C. onchidiocotyle, C. paucispinosa, Nasicola klawei, Hexostoma thynni, Didymocystis sp. 2 (sensu RodrĂ­guez-MarĂ­n et al., 2008), Didymosulcus sp. 2 (sensu RodrĂ­guez-MarĂ­n et al. 2008), Didymosulcus wedli, Didymozoon pretiosus, Nematobothriinae gen. sp. and Wedlia sp. The prevalence of some food-borne parasites (Didymocystis sp. 2, D. pretiosus, Nematobothriinae gen. sp. and Wedlia sp.) had significant differences between localities (p ≀ 0.05). The results showed that the parasite fauna of juvenile tunas is not homogenously distributed in the Mediterranean Sea: parasite assemblages differed between hosts from the Balearic, Ionian, Ligurian, and Tyrrhenian seas, suggesting parasites as possible tags to identify the different tuna populations from the corresponding nursery areas.Postprint0,000

    Grazing history effects on above-and below-ground litter decomposition and nutrient cycling in two co-occurring grasses

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    Fil: Semmartin, MarĂ­a. Universidad de Buenos Aires (UBA). Facultad de AgronomĂ­a. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas vinculadas a la Agricultura (IFEVA); Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Chaneton, Enrique J. Universidad de Buenos Aires (UBA). Facultad de AgronomĂ­a. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas vinculadas a la Agricultura (IFEVA); Argentina.Fil: Chaneton, Enrique J. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET); Argentina.Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Semmartin, MarĂ­a. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET); Argentina.Large herbivores may alter carbon and nutrient cycling in soil by changing above- and below-ground litter decomposition dynamics. Grazing effects may reflect changes in plant allocation patterns, and thus litter quality, or the site conditions for decomposition, but the relative roles of these broad mechanisms have rarely been tested. We examined plant and soil mediated effects of grazing history on litter mass loss and nutrient release in two grazing-tolerant grasses, Lolium multiflorum and Paspalum dilatatum, in a humid pampa grassland, Argentina. Shoot and root litters produced in a common garden by conspecific plants collected from grazed and ungrazed sites were incubated under both grazing conditions. We found that grazing history effects on litter decomposition were stronger for shoot than for root material. Root mass loss was neither affected by litter origin nor incubation site, although roots from the grazed origin immobilised more nutrients. Plants from the grazed site produced shoots with higher cell soluble contents and lower lignin:N ratios. Grazing effects mediated by shoot litter origin depended on the species, and were less apparent than incubation site effects. Lolium shoots from the grazed site decomposed and released nutrients faster, whereas Paspalum shoots from the grazed site retained more nutrient than their respective counterparts from the ungrazed site. Such divergent, species-specific dynamics did not translate into consistent differences in soil mineral N beneath decomposing litters. Indeed, shoot mass loss and nutrient release were generally faster in the grazed grassland, where soil N availability was higher. Our results show that grazing influenced nutrient cycling by modifying litter breakdown within species as well as the soil environment for decomposition. They also indicate that grazing effects on decomposition are likely to involve aerial litter pools rather than the more recalcitrant root compartment

    Grazing-induced changes in plant composition affect litter quality and nutrient cycling in Flooding Pampa grasslands

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    Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Semmartin, MarĂ­a. Universidad de Buenos Aires (UBA). Facultad de AgronomĂ­a. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas vinculadas a la Agricultura (IFEVA); Argentina.Fil: Chaneton, Enrique J. Universidad de Buenos Aires (UBA). Facultad de AgronomĂ­a. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas vinculadas a la Agricultura (IFEVA); Argentina.Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET); Argentina.Fil: Semmartin, MarĂ­a. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET); Argentina.Fil: Chaneton, Enrique J. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas (CONICET); Argentina.Changes in plant community composition induced by vertebrate grazers have been found to either accelerate or slow C and nutrient cycling in soil. This variation may reflect the differential effects of grazing-promoted (G+) plant species on overall litter quality and decomposition processes. Further, site conditions associated with prior grazing history are expected to influence litter decay and nutrient turnover. We studied how grazing-induced changes in plant life forms and species identity modified the quality of litter inputs to soil, decomposition rate and nutrient release in a flooding Pampa grassland, Argentina. Litter from G+ forbs and grasses (two species each) and grazing-reduced (G-) grasses (two species) was incubated in long-term grazed and ungrazed sites. G+ species, overall, showed higher rates of decomposition and N and P release from litter. However, this pattern was primarily driven by the low-growing, high litter-quality forbs included among G+ species. Forbs decomposed and released nutrients faster than either G+ or G- grasses. While no consistent differences between G+ and G- grasses were observed, patterns of grass litter decay and nutrient release corresponded with interspecific differences in phenology and photosynthetic pathway. Litter decomposition, N release and soil N availability were higher in the grazed site, irrespective of species litter type. Our results contradict the notion that grazing, by reducing more palatable species and promoting less palatable ones, should decrease nutrient cycling from litter. Plant tissue quality and palatability may not unequivocally link patterns of grazing resistance and litter decomposability within a community, especially where grazing causes major shifts in life form composition. Thus, plant functional groups defined by species' "responses" to grazing may only partially overlap with functional groups based on species "effects" on C and nutrient cycling

    Plasma deposition of constrained layer damping coatings

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    Plasma techniques are used to generate constrained layer damping (CLD) coatings on metallic substrates. The process involves the deposition of relatively thick, hard ceramic layers on to soft polymeric damping materials while maintaining the integrity of both layers. Reactive plasma sputter-deposition from an aluminium alloy target is used to deposit alumina layers, with Young's modulus in the range 77-220GPa and thickness up to 335 Ό, on top of a silicone film. This methodology is also used to deposit a 40 Ό alumina layer on a conventional viscoelastic damping film to produce an integral damping coating. Plasma CLD systems are shown to give at least 50 per cent more damping than equivalent metal-foil-based treatments. Numerical methods for rapid prediction of the performance of such coatings are discussed and validated by comparison with experimental results

    Nutrient supply and bird predation additively control insect herbivory and tree growth in two contrasting forest habitats

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    Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Kitzberger, Thomas. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche y INIBIOMA-oCONICET. Laboratorio Ecoton; Argentina.Fil: Mazía, Noemí C. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.Fil: Chaneton, Enrique J. Universidad de Buenos Aires (UBA). Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas vinculadas a la Agricultura (IFEVA)-CONICET; Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.It has been suggested that bottom–up and top–down forces interactively control food web dynamics. While top–down effects would increase with resource availability to plants, bottom–up effects would be stronger under low predator abundance. These predictions, however, have rarely been tested at contrasting sites while keeping the dominant plant species unchanged. Furthermore, few studies have factorially manipulated both types of forces in forest communities. For two years, we evaluated the effects of fertiliser (NPK) addition and bird exclusion on tree growth, leaf traits, insect abundance, and folivory rates in a dry/warm and a wet/cold Nothofagus pumilio forest in Patagonia, Argentina. Overall, we found no interaction between nutrient supply and bird predation, although the strength of bottom–up and top–down forces differed markedly between forest sites. Treatment effects were generally weak in the wet forest, where tree growth rates and insect herbivory were low relative to the dry forest. In the dry forest, fertilisation increased sapling growth, insect abundance and folivory, whereas bird exclusion increased leaf damage and reduced tree growth. In the wet forest, fertilisation enhanced leaf nutrient contents and folivore abundance but not sapling growth, while bird exclusion had little impact on insects or trees. These results imply that factors other than nutrients and birds were important in controlling tree growth and folivore activity in the wet forest. While treatment effect sizes varied widely among feeding guilds, in general, nutrient effects on folivores were stronger than predator effects. We conclude that, within the time‐frame of this study, tree growth and herbivory were additively affected by soil nutrients and predator presence, as bird exclusion effects did not change with elevated folivore activity on fertilised trees. We also show that both top–down and bottom–up cascades were weaker in a forest site characterised by slow‐growing juvenile trees subjected to low folivore pressure

    Variable strength of top‐down effects in Nothofagus forests: bird predation and insect herbivory during an ENSO event

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    Fil: MazĂ­a, NoemĂ­ C. Universidad de Buenos Aires. Facultad de AgronomĂ­a; Argentina.Fil: Chaneton, Enrique J. Universidad de Buenos Aires (UBA). Facultad de AgronomĂ­a. IFEVA- CONICET; Argentina.Fil: Kitzberger, Thomas. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono-CONICET; Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad de Buenos Aires. Facultad de AgronomĂ­a; Argentina.Predators are thought to play a key role in controlling herbivory, thus having positive indirect effects on plants. However, evidence for terrestrial trophic cascades is still fragmentary, perhaps due to variation in top-down forces created by environmental heterogeneity. We examined the magnitude of predation effects on foliar damage by chewing insects and mean leaf size, by excluding birds from saplings in ‘dry’ and ‘wet’ Nothofagus pumilio forests in the northern Patagonian Andes, Argentina.The experiment lasted 2 years encompassing a severe drought during the La Niña phase of a strong El Niño/Southern Oscillation event, which was followed by unusually high background folivory levels. Insect damage was consistently higher in wet than in dry forest saplings. In the drought year (1999), bird exclusion increased folivory rates in both forests but did not affect tree leaf size. In the ensuing season (2000), leaf damage was generally twice as high as in the drought year. As a result, bird exclusion not only increased the extent of folivory but also significantly decreased sapling leaf size.The latter effect was stronger in the wet forest, suggesting compensation of leaf area loss by dry forest saplings. Overall, the magnitude of predator indirect effects depended on the response variable measured. Insectivorous birds were more effective at reducing folivory than at facilitating leaf area growth. Our results indicate that bird-initiated trophic cascades protect N. pumilio saplings from insect damage even during years with above-normal herbivory, and also support the view that large-scale climatic events influence the strength of trophic cascades
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