State University of Santa Cruz

About: State University of Santa Cruz is a education organization based out in Ilhéus, Brazil. It is known for research contribution in the topics: Population & Species richness. The organization has 3266 authors who have published 4642 publications receiving 51876 citations. The organization is also known as: Universidade Estadual de Santa Cruz.

An improved extraction protocol for metagenomic DNA from a soil of the Brazilian Atlantic Rainforest.

Abstract: The need for the prospecting for and identification of new biomolecules is a reality. Molecular techniques allow access to the metabolic potential of microorganisms via the isolation of DNA from environmental samples, i.e., without the application of micro- bial culture techniques. With its great biological diversity, the Atlantic Rainforest biome has a soil rich in organic matter, some components of which interfere negatively in the reactions necessary for the ex- ploitation of its biotechnological potential. Here, we describe a proto- col for the optimization of the treatment of soil samples before DNA extraction. The new methodology gives higher yield and quality of extracted DNA as compared with pre-existing techniques, facilitat- ing the amplification and digestion of environmental DNA, and thus allows optimal exploitation of the genetic potential of the Atlantic Rainforest biome.

Castor oil and commercial thermoplastic polyurethane membranes modified with polyaniline: a comparative study

Abstract: The study of conducting polymeric membranes is decisive in some areas, as in fuel cells and electrodialysis. This work aims the study of membranes using conventional and conductive polymers blends. Two types of polyurethane were used as conventional polymers, commercial thermoplastic polyurethane and polyurethane synthesized from castor oil and 4-4-dicyclohexylmethane isocyanate. Two kinds of conducting polymers were used, polyaniline doped with organic acid and a self doped polyaniline. The polymers and the membranes were characterized by electrical conductivity, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The synthesis of the membranes produced was proper, featuring a complete reaction, analyzed by FTIR. The membranes also showed good mechanical properties and thermal stability ( ≈ 220 °C). Among the membranes studied, the polyaniline doped with p-toluenesulphonic acid obtained higher thermal and viscoelastic properties. Thus they can be used in separation techniques using membranes.

Photosynthetic characteristics of ornamental passion flowers grown under different light intensities

Abstract: Responses of leaf gas exchange, fluorescence emission, chlorophyll concentration, and morpho-anatomical features to changes in photosynthetic photon flux density (PPFD) were studied in three wild ornamental species of Passiflora L. to select sun and shade species for landscaping projects. Artificial shade was obtained with different shading nylon nets, under field conditions, which allowed the reduction of 25, 50, and 75% of global radiation, along with a control treatment under full sunlight. For Passiflora morifolia the highest mean values of light-saturated net photosynthetic rate (P Nmax) and light compensation point (LCP) were observed at 50 and 25% shade, respectively, while the highest values of dark respiration rate (R D) and apparent quantum yield (α) were observed at 75% shade. For Passiflora suberosa litoralis the highest value of P max was observed at full sunlight. The highest mean values for P max, R D, and LCP for Passiflora palmeri var. sublanceolata were obtained at 25% shade. The highest values of net photosynthetic rate (P N) for P. morifolia, P. palmeri var. sublanceolata, and P. suberosa litoralis were 21.09, 16.15, and 12.36 μmol(CO2) m−2 s−1, observed at 50 and 75% shade and full sunlight, respectively. The values of the minimal chlorophyll fluorescence (F0) were significantly different in P. suberosa litoralis and P. palmeri var. sublanceolata, increasing with the increase of the irradiance. In contrast, the values of maximum photochemical efficiency of PSII (Fv/Fm) were significantly different only in P. suberosa litoralis, being higher at 75%, progressively reducing with the increase of PPFD levels. The total concentration of chlorophyll (Chl) was higher in shaded plants than in the ones cultivated in full sunlight. On the other hand, the values of Chl a/b ratio were reduced in shaded plants. A significant effect of shade levels on leaf area (LA) and specific leaf area (SLA) was found for the three species, whose highest mean values were observed at 75% shade. The thickness of foliar tissues was significantly higher for the three species at full sunlight and 25% shade. These results suggested that P. morifolia and P. palmeri var. sublanceolata appeared to be adapted to moderate shade conditions. P. suberosa litoralis presented higher plasticity to greater variation of the irradiance levels, while the photoinhibition was one of the limiting factors for this species at full sunlight.

Ectopic expression of a fruit phytoene synthase from Citrus paradisi Macf. promotes abiotic stress tolerance in transgenic tobacco.

Abstract: Abscisic acid (ABA) is an important regulator of plant responses to environmental stresses and an absolute requirement for stress tolerance. Recently, a third phytoene synthase (PSY3) gene paralog was identified in monocots and demonstrated to play a specialized role in stress-induced ABA formation, thus suggesting that the first committed step in carotenogenesis is a key limiting step in ABA biosynthesis. To examine whether the ectopic expression of PSY, other than PSY3, would similarly affect ABA level and stress tolerance, we have produced transgenic tobacco containing a fruit-specific PSY (CpPSY) of grapefruit (Citrus paradisi Macf.). The transgenic plants contained a single- or double-locus insertion and expressed CpPSY at varying transcript levels. In comparison with the wild-type plants, the CpPSY expressing transgenic plants showed a significant increase on root length and shoot biomass under PEG-, NaCl- and mannitol-induced osmotic stress. The enhanced stress tolerance of transgenic plants was correlated with the increased endogenous ABA level and expression of stress-responsive genes, which in turn was correlated with the CpPSY copy number and expression level in different transgenic lines. Collectively, these results provide further evidence that PSY is a key enzyme regulating ABA biosynthesis and that the altered expression of other PSYs in transgenic plants may provide a similar function to that of the monocot's PSY3 in ABA biosynthesis and stress tolerance. The results also pave the way for further use of CpPSY, as well as other PSYs, as potential candidate genes for engineering tolerance to drought and salt stress in crop plants.