1,354 research outputs found
Zinc ions alter morphology and chitin deposition in an ericoid fungus
A sterile mycelium PS IV, an ascomycete capable of establishing ericoid mycorrhizas, was used to investigate how zinc ions affect the cellular mechanisms of fungal growth. Asignificant reduction of the fungal biomass was observed in the presence of millimolar zinc concentrations; this mirrored conspicuous changes in hyphal morphology which led to apical swellings and increased branching in the subapical parts. Specific probes for fluorescence and electron microscopy localised chitin, the main cell wall polysaccharide, on the inner part of the fungal wall and on septa in control specimens. In Zn-treated mycelium, hyphal walls were thicker and a more intense chitin labelling was detected on the transverse walls. Aquantitative assay showed a significant increase in the amount of chitin in metal- treated hyphae
Sensitivity of surface fluxes in the ECMWF land surface model to the remotely sensed leaf area index and root distribution: Evaluation with tower flux data
The surface-atmosphere turbulent exchanges couple the water, energy and carbon budgets in the Earth system. The biosphere plays an important role in the evaporation process, and vegetation related parameters such as the leaf area index (LAI), vertical root distribution and stomatal resistance are poorly constrained due to sparse observations at the spatio-temporal scales at which land surface models (LSMs) operate. In this study, we use the Carbon Hydrology Tiled European Center for Medium-Range Weather Forecasts (ECMWF) Scheme for Surface Exchanges over Land (CHTESSEL) model and investigate the sensitivity of the simulated turbulent fluxes to these vegetation related parameters. Observed data from 17 FLUXNET towers were used to force and evaluate model simulations with different vegetation parameter configurations. The replacement of the current LAI climatology used by CHTESSEL, by a new high-resolution climatology, representative of the station’s location, has a small impact on the simulated fluxes. Instead, a revision of the root profile considering a uniform root distribution reduces the underestimation of evaporation during water stress conditions. Despite the limitations of using only one model and a limited number of stations, our results highlight the relevance of root distribution in controlling soil moisture stress, which is likely to be applicable to other LSMs
Integrative taxonomy of a new Redudasys species (Gastrotricha: Macrodasyida) sheds light on the invasion of fresh water habitats by macrodasyids
The order Macrodasyida (Gastrotricha) includes over 350 marine species, and only 3 freshwater species (Marinellina flagellata, Redudasys fornerise, R. neotemperatus). Herein we describe a new freshwater species of Macrodasyida, Redudasys brasiliensis sp. nov., from Brazil through an integrative taxonomic approach. The external morphology and internal anatomy were investigated using differential interference contrast microscopy, confocal microscopy, scanning and transmission electron microscopy. The systematization of the new taxon was inferred by nuclear (18S and 28S) and mitochondrial (COI) genes, and its intra-order relationships were assessed using data from most of available macrodasyids. Phylogenetic analyses yielded congruent trees, in which the new taxon is nested within the family Redudasyidae, but it was genetically distinct from the other species of the genus Redudasys. The new species shares the gross morphology and reproductive traits with other Redudasyidae and the presence of only 1 anterior adhesive tube per side with Redudasys neotemperatus, but it has a specific pattern of ventral ciliation and muscle organization. Results support the hypothesis that dispersion into fresh water habitats by Macrodasyida and Chaetonotida taxa occurred independently and that within Macrodasyida a single lineage invaded the freshwater environment only once. Furthermore, the Neotropical region seems to be peculiar for the evolution of the freshwater macrodasyid clade9CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP478825/2013ETC-00017-132014/23856-
Heterogeneity of lineage involvement by trisomy 8 in myelodysplastic syndrome. A multiparameter analysis combining conventional cytogenetics, DNA in situ hybridization, and bone marrow culture studies
Ecotoxicological assessment of irrigation water for vegetables in a watershed region of Greater São Paulo
The aim of the present study was to evaluate the quality of irrigation water for vegetables in a Greater São Paulo watershed region. Acute and chronic ecotoxicity bioassays with Dugesia tigrina and Selenastrum capricornutum and geno/mutagenicity assays with Allium cepa were performed, as well as microbiological assays for total and thermotolerant coliforms, according to the legislation. The ecotoxicological data did not show significant toxicity in any of the samples. However, surface water genotoxic effect was detected in 2 out of the 3 points and mutagenic effect in all three sampled points, as well as in the sediment, in the Allium cepa test. Such high prevalence of total and thermotolerant coliforms in all samples at the three points indicates a compromised environmental integrity of the basin due to high loads of organic pollution, probably of clandestine origin. No emissions of industrial origin were detected in the region. Thus, taken together, the results suggest that agricultural activity itself may account for the impacts in these water bodies. The present study represents a contribution to the scarce data available in the literature about this important Greater São Paulo region
Low-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion
Muscle regeneration is a complex phenomenon, involving replacement of damaged fibers by new muscle fibers. During this process, there is a tendency to form scar tissue or fibrosis by deposition of collagen that could be detrimental to muscle function. New therapies that could regulate fibrosis and favor muscle regeneration would be important for physical therapy. Low-level laser therapy (LLLT) has been studied for clinical treatment of skeletal muscle injuries and disorders, even though the molecular and cellular mechanisms have not yet been clarified. The aim of this study was to evaluate the effects of LLLT on molecular markers involved in muscle fibrosis and regeneration after cryolesion of the tibialis anterior (TA) muscle in rats. Sixty Wistar rats were randomly divided into three groups: control, injured TA muscle without LLLT, injured TA muscle treated with LLLT. The injured region was irradiated daily for four consecutive days, starting immediately after the lesion using an AlGaAs laser (808 nm, 30 mW, 180 J/cm[superscript 2]; 3.8 W/cm[superscript 2], 1.4 J). The animals were sacrificed on the fourth day after injury. LLLT significantly reduced the lesion percentage area in the injured muscle (p < 0.05), increased mRNA levels of the transcription factors MyoD and myogenin (p < 0.01) and the pro-angiogenic vascular endothelial growth factor (p < 0.01). Moreover, LLLT decreased the expression of the profibrotic transforming growth factor TGF-β mRNA (p < 0.01) and reduced type I collagen deposition (p < 0.01). These results suggest that LLLT could be an effective therapeutic approach for promoting skeletal muscle regeneration while preventing tissue fibrosis after muscle injury.National Institutes of Health (U.S.) (grant R01AI050875)Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Pesquisas (Brazil)Fundação de Amparo à Pesquisa do Estado de São Paul
A solar photothermocatalytic approach for the CO2 conversion: Investigation of different synergisms on CoO-CuO/brookite TiO2-CeO2 catalysts
The photoactive features of the least common polymorph of TiO2, i.e. brookite, were combined with the thermocatalytic redox ones of cerium oxide, focusing on the effects of the addition of small amounts of Co-Cu oxides for the solar CO2 conversion. By considering the characterization data, a surface segregation of the hosted metal oxides on the TiO2-CeO2 composite was evidenced, and their presence increased the amount of oxygen vacancies and improved the charge carriers separation. The bimetallic oxides-based sample was the most performing one in the photocatalytic carbon dioxide reduction at room temperature. The formation of carbon monoxide and methane was 5 and 0.5 μmol g−1h−1, respectively, i.e. about 10 times higher than that found with bare brookite. A further enhancement was obtained with the same CoO-CuO/TiO2-CeO2 catalyst applying the photothermal approach. The CO2-TPD and the FTIR measurements highlighted the high interaction between CO2 and the surface sites
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