312 resultados para Polietileno glicol
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
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Pós-graduação em Agronomia (Agricultura) - FCA
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Studies of the germination response of seeds subjected to artificial stresses are provided tools for better understanding of the survivability and adaptation of these species in natural stress conditions such as drought or saline soils, common in agricultural and forest regions, contributing significantly to the development of management strategies. Thus, the purpose of this study was to evaluate the possible effects of water and salt stress on germination of Urochloa decumbens and Urochloa ruziziensis. The test was conducted at the Faculty of Technology of São Paulo, campus of Capon Bonito. The seeds were sown with four replicates of 50 seeds in paper soaked in solutions with the potentials of 0.0, -0.2, -0.4 and -0.8 MPa, induced with polyethylene glycol (PEG 6000) and NaCl. The germination test was conducted at 25 degrees C in the presence of light, evaluating the first test score at seven days after sowing, and weekly germination (normal seedlings) until 35 days. We calculated the index of germination rate. The results allowed the conclusion that water stress causes a greater reduction in force, speed of germination and cumulative germination of seeds of U. decumbens and U. ruziziensis than salt stress. The species U. decumbens showed higher tolerance to water and salt stresses.
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This study aimed to evaluate crambe seeds germination and vigor under water stress conditions induced by polyethylene glycol solutions. The seeds were germinated on substrate moistened with polyethylene glycol solutions, using the osmotic potentials of 0 (control), -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa. The seeds germination was evaluated by normal seedlings and root emission percentages. Vigor was evaluated by germination average time, relative frequency, velocity and synchronization index. It was observed that more negative osmotic potential caused significant reduction in crambe seed germination and vigor, and no normal seedlings was observed at potentials below -0.6 MPa.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Microbiologia - IBILCE
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The plants are subject to the conditions of multiple stresses, such as water and salt stress, which limit their development and their chances of survival. Aware of the factors that control seed germination can generate support for management strategies of weed species. The objective of this study was to evaluate the possible effects of water stress caused by PEG and NaCl solutions on germination of wild Raphanus raphanistrum and Senna obtusifolia seeds. The seeding was done with four repetitions of 50 seeds on moistened paper with solutions of polyethylene glycol (PEG 6000) and NaCl at osmotic potentials of 0.0, -0.2, -0.4 and -0.8 MPa. The germination test was conducted at 25 degrees C in the presence of light, evaluating the first test score to seven days after sowing, and weekly, germination (normal seedlings) until 35 days; it was also calculated the index germination rate. The results allowed the conclusion that water stress by PEG causes a greater reduction in force, speed of germination and accumulated germination of seeds of Raphanus raphanistrum and Senna obtusifolia seeds. The Senna obtusifolia was more tolerant to water stress.
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Using ELISA technique, natural antibodies against self and non self antigens were determined in 80 patients chronically intected by T. cruzi and 40 individuals suffering from a deep mycosis frequentely found in Latin Amarica (Paracoccidioidomycosis - PCM). Two forms of PCM were investigated: adult forms and juvenil type of disease. Eighty percent (80%) of the former group had significantly elevated anti-laminin antibody levels (M=4.7,SD±1.8) compared with healthy controls and different specificities of antibody were associated with anti-laminin in pathological sera. A notable binding to cytoskeletal proteins was observed, specially with band 3 and their peptides derivates, such as 62 kDa peptide. By means of Protein A chromatography we were able to show that natural anti-Gal antibodies may be bound by their Fab region to other immunoglobulins and/or to Protein A by alternative sites of binding. The finding of lgG anti-Gal antibodies in circulating immune complexes isolated from chagasic sera supported the first alternative. However, it is possible that some of lgG anti-Gal antibodies, belong to VH111 subgroup of immunoglobulins, that bind directly to Protein A. Among the 40 sera from PCM examined, the majority was considered as not exhibiting a signilicantly higher binding than normal sera to antigens tested. However thirty percent (30%) of the chronic patients had an increased levels of natural antibodies at least for one specificity such as actyn, myosin and Gala1,3Gal epitopes. ln juvenil type of PCM the mean value found for actyn was also increased 2,42 (range 1,0 to 5,3). Utilizing the polyethylene glicol precipitation the presence of circulating immune complexes was investigated in PCM sera. Specific antibodies for soluble antigens from P. brasiliensis and natural antibodies against myoglobin, myosin and Gala1,3 Gal epitopes were characterized
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)