281 research outputs found

    Water use in Citrus: effect on porosity in water retention in a “Latossolo vermelho-escuro” of Northeast of Estado de Sao Paulo

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    [Abstract] The objective of this research was to study the porosity, bulk density and retention of water of an Oxisol, located in the Northwestern region of SĂŁo Paulo state, Brazil. The soil was cultivated with Citrus sp., to which green manure was applied between rows for three years. Each of six species of green manure crops (Crotalaria junceaL., Mucunade eringian a Steph. & Bart., Canavalia ensiformis L. DC., Cajanus cajan L., Lablab purpureum L. and Ricinus communis L.) were seeded for three years (1995, 1996 and 1997) between Citrus rows, plus a treatment with a mix of all six species and a control (natural regrowth af vegetation). The experimental design was a randomized complete block design, with four replications for each of the eight treatments. Water retention, microporosity, macroporosity, total porosity and bulk density were analyzed in the beginning (1995) and end (1997) of the experiment, at three depth ranges (0-0.10; 0.10-0.20 and 0.20-0.40m). We concluded that there were statistically significant differences for bulk density, macroporosity, total porosity and retention of water among the different soil depth ranges; there were no significant differences among treatments though

    Geostatistical analysis of surface microtopography on tilled soil surfaces

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    [Abstract] Depressions at the soil surface influence temporal water storage and hence runoff generation. Surface microtopography of tilled soils is subject to spatial and temporal changes. The objective of this study was to evaluate whether elevation data with different resolutions have a comparable patters of spatial dependence. Point elevation measurements were taken on 25 tilled soil surfaces after mouldboard plough across a range of cumulative precipitation and roughness. Height was measured with a pinmeter. The grid spacing of the experimental surfaces was 2 cm and sample density was diminished by leaning point out to obtain 4 cm x 4 cm and 6 cm x 2 cm grids. The spatial structure of the studied surfaces was modelled by spherical and exponential semivariograms with no o very small nugget components. Changing sample grid spacing didn’t influence the adjusted semivariogram type, but could originate small modifications of the sill and/or range values

    Dendritic Cells Transfected with scFv from Mab 7.B12 Mimicking Original Antigen gp43 Induces Protection against Experimental Paracoccidioidomycosis

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    Paracoccidioidomycosis (PCM), endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), which primarily attacks lung tissue. Dendritic cells (DCs) are able to initiate a response in naĂŻve T cells, and they also participate in Th-cell education. Furthermore, these cells have been used for therapy in several disease models. Here we transfected DCs with a plasmid (pMAC/PS-scFv) encoding a single chain variable fragment (scFv) of an anti-Id antibody that is capable of mimicking gp43, the main antigenic component of P. brasiliensis. First, Balb/c mice were immunized subcutaneously with pMAC/PS-scFv and, after seven days, scFv protein was presented to the regional lymph nodes cells. Moreover, we showed that the DCs transfected with scFv were capable of efficiently activating proliferation of total lymph node cells and inducing a decrease in lung infection. Therefore, our results suggested that the use of scFv-transfected DCs may be a promising therapy in the paracoccidioidomycosis (PCM) model

    Antifungal activity of amphotericin B conjugated to nanosized magnetite in the treatment of paracoccidioidomycosis

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    This study reports on in vitro and in vivo tests that sought to assess the antifungal activity of a newly developed magnetic carrier system comprising amphotericin B loaded onto the surface of pre-coated (with a double-layer of lauric acid) magnetite nanoparticles. The in vitro tests compared two drugs; i.e., this newly developed form and free amphotericin B. We found that this nanocomplex exhibited antifungal activity without cytotoxicity to human urinary cells and with low cytotoxicity to peritoneal macrophages. We also evaluated the efficacy of the nanocomplex in experimental paracoccidioidomycosis. BALB/c mice were intratracheally infected with Paracoccidioides brasiliensis and treated with the compound for 30 or 60 days beginning the day after infection. The newly developed amphotericin B coupled with magnetic nanoparticles was effective against experimental paracoccidioidomycosis, and it did not induce clinical, biochemical or histopathological alterations. The nanocomplex also did not induce genotoxic effects in bone marrow cells. Therefore, it is reasonable to believe that amphotericin B coupled to magnetic nanoparticles and stabilized with bilayer lauric acid is a promising nanotool for the treatment of the experimental paracoccidioidomycosis because it exhibited antifungal activity that was similar to that of free amphotericin B, did not induce adverse effects in therapeutic doses and allowed for a reduction in the number of applications
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