Meio ambiente, empresário e gorverno: conflitos ou parceria?

O processo de concessão de licença ambiental para determinado tipo de atividade é o exemplo escolhido neste artigo para qualificar pontos de contato, mostrando que - no âmbito da gestão do meio ambiente, que se define tendencialmente conflituosa - essa interface é, em geral, problemática. Sugere-se que algumas premissas básicas devam nortear a relação público-privado, como a da coresponsabilidade, em prol de resultados menos agressivos ao ambiente. Através da apresentação de uma experiência bem­sucedida de integração das atuações dos setores em questão, mostra-se como se pode conduzir esforços para o alcance de uma interação mais eficaz entre o público e o privado.

Mycorrhizal colonization and phenolic compounds accumulation on roots of Eucalyptus dunnii maiden inoculated with ectomycorrhizal fungi

Compatibility between Eucalyptus dunnii and the ectomycorrhizal fungi Hysterangium gardneri and Pisolithus sp. - from Eucalyptus spp. -, Rhizopogon nigrescens and Suillus cothurnatus - from Pinus spp.-, was studied in vitro. Pisolithus sp., H. gardneri and S. cothurnatus colonized the roots. Pisolithus sp. mycorrhizas presented mantle and Hartig net, while H. gardneri and S. cothurnatus mycorrhizas presented only mantle. S. cothurnatus increased phenolics level on roots. Pisolithus sp. and R. nigrescens decreased the level of these substances. The isolates from Eucalyptus seem to be more compatible towards E. dunnii than those from Pinus. The mechanisms involved could be related, at least in the cases of Pisolithus and Suillus, to the concentration of phenolics in roots.

Influência de porta-enxertos na resistência de mudas de cajueiro ao estresse salino

O objetivo deste trabalho foi avaliar a influência de porta-enxertos na resistência de mudas de cajueiro (Anacardium occidentale L.) à salinidade. As mudas foram obtidas pela enxertia do clone BRS 226 sobre os porta-enxertos CAPI 4, CCP 09 e BRS 226. Foram expostas a meio hidropônico sem NaCl (controle) ou com NaCl 200 mM (tratamento salino), sob condições controladas de temperatura, umidade e luminosidade, durante 12 dias. O delineamento foi o inteiramente casualizado, em esquema fatorial 3x2 (três combinações de enxerto/porta-enxerto e duas concentrações de NaCl), com quatro repetições. Foram determinados a concentração de Na+, Cl-, K+ e solutos orgânicos e os sintomas visuais de toxicidade nas folhas. Os conteúdos de Na+ e Cl-, a relação K+/Na+ e as concentrações de aminoácidos e de prolina livres nas folhas tiveram relação direta com os sintomas visuais de toxicidade. Os porta-enxertos CAPI 4, CCP 09 e BRS 226 foram classificados como sensível, intermediário e resistente à salinidade elevada, respectivamente. Essa variação foi decorrente da influência do porta-enxerto na partição do Na+ e do Cl-.

Síntese da hidroxiapatita e refinamento estrutural por difração de raios-x

A sample of hydroxyapatite was synthesized and its crystalline structure was analyzed by X-ray diffraction by means of the Rietveld method. Two functions were used to fit the peak profiles, modified Voigt (TCHZ) and Pearson VII. The occupational factors and lattice parameters obtained by both models show that the sample does not contain relevant cationic substitutions. The interatomic distances from Ca1 to oxygens O1, O2 and O3 were adequate for a pure hydroxyapatite without defect at site Ca1. Besides, the use of multiple lines in planes (300) and (002) associated with the model Pearson VII resulted in good agreement with the TCHZ model with respect to the size-strain effectswith an ellipsoidal shape of crystallites. In conclusion, the procedures adopted in the synthesis of hydroxyapatite produced a pure and crystalline material. The experimental results of transmission electron microscopy confirmed the predicted shape of crystals.

AVALIAÇÃO DA BIOACUMULAÇÃO DE METAIS EM Cyprinus carpio PELA INTERAÇÃO COM SEDIMENTO E ÁGUA DE RESERVATÓRIO

Bioaccumulation of Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined in the gills and liver of Cyprinus carpio and related to concentrations in the sediment and water of the Alagados Reservoir, Ponta Grossa/Paraná. Cd and Fe exceeded the legal limit for water. Fe was the most abundant metal in the reservoir's water and sediment. The metals in the sediment were below the level of probable adverse effects on biota. There were no significant differences between sampling sites for water and sediment. Liver and gills had higher concentrations of Al, Fe and Zn, with a significant increase in Al (P > 0.05) compared to the increase in weight and size of the specimens. Statistically, gills showed higher concentrations of Al, Cd, Co, Cr, Mn and Zn and liver higher concentrations of Cu and Fe. Co, Cu, Fe, Mn and Zn showed significant differences (P < 0.01) between the organs. The bioaccumulation factors (BAF) showed that the interaction of water with gills promotes greater accumulation of metals in this organ. Despite the low concentrations in the reservoir, bioaccumulation of metals in gills and liver of C. carpio occurs by its interaction with contaminated water and sediment, respectively.

Some physico-chemical parameters that influence proteinase K resistance and the infectivity of PrP Sc after high pressure treatment

Crude brain homogenates of terminally diseased hamsters infected with the 263 K strain of scrapie (PrP Sc) were heated and/or pressurized at 800 MPa at 60ºC for different times (a few seconds or 5, 30, 120 min) in phosphate-buffered saline (PBS) of different pH and concentration. Prion proteins were analyzed on immunoblots for their proteinase K (PK) resistance, and in hamster bioassays for their infectivity. Samples pressurized under initially neutral conditions and containing native PrP Sc were negative on immunoblots after PK treatment, and a 6-7 log reduction of infectious units per gram was found when the samples were pressurized in PBS of pH 7.4 for 2 h. A pressure-induced change in the protein conformation of native PrP Sc may lead to less PK resistant and less infectious prions. However, opposite results were obtained after pressurizing native infectious prions at slightly acidic pH and in PBS of higher concentration. In this case an extensive fraction of native PrP Sc remained PK resistant after pressure treatment, indicating a protective effect possibly due to induced aggregation of prion proteins in such buffers.