651 research outputs found

    Characterization, Classification And Analysis Of The Main Properties Of The Southwestern Goias Soil

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    Characterization of the soil and the grouping of its properties through main component analysis can assist in the classification and observation of the consequences of the conversion of native forest areas in pastures. Such data can aid in management practices. Considering the lack of studies in Cerrado soils of south-western Goias, developed metagranites of Jurubatuba suite, the objective was to classify and study the physical, chemical and mineralogical soil (under native forest and pasture) Southwest of Goias. Soil sampling and classification followed the Field Methods Manual and the Brazilian System of Soil Classification, respectively. The physical, chemical and mineralogical soil were studied, as well as main component analysis made for these attributes. The profile 1 under native forest was classified as "Cambissolo Háplico Tb eutrófico latossólico". The profile 2 under degraded pasture was rated "Latossolo Amarelo eutrófico típico". In addition, the profile 3 under rotated pasture was rated as "Latossolo Vermelho eutrófico chernossólico". It was observed that the "Latossolos" have higher bulk density and soil penetration resistance, indicating greater soil compaction. They showed high amounts of iron oxides and minor amount of nutrients such as calcium and magnesium. The principal component analysis allowed the grouping of profiles into two groups. Group 1 brought together the properties related to "Latossolos", and the second was related to "Cambissolo" properties. Thus, the principal components analysis aids the understanding of soil properties and the grouping of soils with similar characteristics, the level of order and management.3731135115

    Genetic Divergence Among Accessions Of Cassava (manihot Esculenta Crantz) Sampled In The Tapajós Region, State Of Pará, Using Agronomic Characters And Microsatellite Markers

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    The aim of this work was to estimate the genetic divergence among accessions of cassava sampled in the Tapajós region in the State of Pará, Brazil, and conserved at the Regional Germplasm Bank of Eastern Amazon, using agronomic descriptors and molecular markers. Twenty-two accessions of cassava were evaluated in the field for two successive years, based on six agronomic descriptors in twelve-months-old plants without a specific experimental design. Accessions were also evaluated with eleven microsatellite loci in an automatic DNA analyser. Descriptive and multivariate statistical analyses were applied. Based on principal components analysis, the character weight of the aerial portion of the plant contributed most to the phenotypical variation. The six traits were used in the analysis of genetic dissimilarity between accessions, and the correlation between matrices generated by morphological and molecular data was estimated. The matrices of genetic dissimilarity were used in the construction of dendrograms using the UPGMA method. We observed a high variation of agronomical descriptors and molecular markers evaluated, which were capable to separate the accessions into distinct groups. A weak positive correlation was detected among the two matrices of genetic distances, which indicates the possibility to explore the genetic diversity using crossings and accessions Amarelinha 36 and Olho roxo 13 are divergent and potentially promising for the generation of heterotic hybrids.3752989300

    Biochemical, genetic and zoosporicidal properties of cyclic lipopeptide surfactants produced by Pseudomonas fluorescens

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    Zoospores play an important role in the infection of plant and animal hosts by oomycetes and other zoosporic fungi. In this study, six fluorescent Pseudomonas isolates with zoosporicidal activities were obtained from the wheat rhizosphere. Zoospores of multiple oomycetes, including Pythium species, Albugo candida, and Phytophthora infestans, were rendered immotile within 30 s of exposure to cell suspensions or cell culture supernatants of the six isolates, and subsequent lysis occurred within 60 s. The representative strain SS101, identified as Pseudomonas fluorescens biovar II, reduced the surface tension of water from 73 to 30 mN m-1. The application of cell suspensions of strain SS101 to soil or hyacinth bulbs provided significant protection against root rot caused by Pythium intermedium. Five Tn5 mutants of strain SS101lacked the abilities to reduce the surface tension of water and to cause lysis of zoospores. Genetic characterization of two surfactant-deficient mutants showed that the transposons had integrated into condensation domains of peptide synthetases. A partially purified extract from strain SS101 reduced the surface tension of water to 30 mN m-1 and reached the critical micelle concentration at 25 micrograms ml-1. Reverse-phase high-performance liquid chromatography yielded eight different fractions, five of which had surface activity and caused lysis of zoospores. Mass spectrometry and nuclear magnetic resonance analyses allowed the identification of the main constituent as a cyclic lipopeptide (1,139 Da) containing nine amino acids and a 10-carbon hydroxy fatty acid. The other four zoosporicidal fractions were closely related to the main constituent, with molecular massesranging from 1,111 to 1,169 Da

    The initial months of antiretroviral therapy and its influence on AGEs, HMGB1, and sRAGE levels in asymptomatic HIV-infected individuals

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    The development of the typical comorbidities of aging which currently affects people living with HIV/AIDS (PLWHA) can be partially ascribed to the persistent immune activation and chronic inflammation characterizing these individuals. The aim of this study was to analyze the effect exerted by combined antiretroviral therapy (cART) administration on plasma levels of HMGB1 (high mobility group box protein-1), AGEs (advanced glycation end products), their soluble receptor sRAGE, cytokines, C-reactive protein (CRP), and some metabolic markers in asymptomatic PLWHA. Analyses were performed longitudinally in 30 PLWHA, before and about 6\u201312 months after cART initiation. We observed that lower levels of AGEs in post-cART group were accompanied by an increase of CRP and triglyceride levels already in the early months of therapy. Because of the current ever-earlier recommendations to start cART and its prolonged use, these and other markers should be investigated in order to monitor and postpone the appearance of non-AIDS comorbidities in PLWHA

    Antiretroviral therapy initiation alters the redox system of asymptomatic HIV-Infected individuals

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    Background. The combination antiretroviral therapy (cART) increases the oxidative stress in HIV-infected people, which in turn favors the onset and aggravation of non-AIDS comorbidities, a common situation affecting these individuals. We aimed to evaluate the influence of cART initiation on oxidative stress parameters. This is a longitudinal study including 30 asymptomatic patients divided according to their CD4+ T cell count (G1: 500 cell/mL) before (M0) and after (M1) cART initiation. We analyzed total antioxidant capacity (TAC), fat-soluble vitamins, malondialdehyde, 8-isoprostane, and DNA damage. Results. Results showed a decrease in TAC, retinol, \u3b1-tocopherol, and some carotenoids, in addition to a significant increase in DNA damage at M1. These changes were more evident in G2 subjects. Moreover, there was a significant 8-isoprostane increase at M1 in individuals belonging to G1. Conclusion. The results indicate that cART interfered in the redox system, mainly by reducing the antioxidant defenses. In addition, patients who had CD4+ T counts higher than 500 cells/mm3 showed more susceptibility to genotoxicity, while patients with less CD4+ T counts displayed more damage triggered by lipoperoxidation. Considering the early beginning of cART, its chronic use, and its capacity to alter the redox status, further long-term studies on larger cohorts are needed to define the best time to initiate therapy and to investigate new strategies to delay the development of non-AIDS diseases
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