Ecological interpretations of the leaf anatomy of amphibious species of Aeschynomene L. (Leguminosae - Papilionoideae)

We present the leaf anatomy of seven amphibious species of Aeschynomene L. (Papilionoideae, Leguminosae), interpreting their structures and ecological functions, and also, providing information on which their taxonomy can be based, especially of morphologically similar species. We evaluated Aeschynomene americana, A. ciliata, A. evenia, A. denticulata, A. fluminensis, A. rudis and A. sensitiva. The anatomy corroborates the separation of the series Americanae, Fluminenses, Indicae and Sensitivae, with the shape of the petiole, types of trichomes and quantity of vascular units in the petiole as main characteristics to delimit the species. The petiole shape varies from cylindric in A. americana, A. sensitiva and A. fluminensis, to triangular in A. evenia and quadrangular in A. rudis, A. denticulata and A. ciliata. We observed four types of trichomes: hydathode trichome, long conic trichome, short conic trichome and bulb-based trichome. The hydathode trichome was the most common, except for A. americana and A. fluminensis. Species with higher affinity with water share similar adaptive characteristics, including hydathode trichomes described for the first time for the genus. This article adds unseen descriptions for the genus and on the adaptation factors of the amphibious species

Ecological interpretations of the leaf anatomy of amphibious species of Aeschynomene L. (Leguminosae - Papilionoideae)

We present the leaf anatomy of seven amphibious species of Aeschynomene L. (Papilionoideae, Leguminosae), interpreting their structures and ecological functions, and also, providing information on which their taxonomy can be based, especially of morphologically similar species. We evaluated Aeschynomene americana, A. ciliata, A. evenia, A. denticulata, A. fluminensis, A. rudis and A. sensitiva. The anatomy corroborates the separation of the series Americanae, Fluminenses, Indicae and Sensitivae, with the shape of the petiole, types of trichomes and quantity of vascular units in the petiole as main characteristics to delimit the species. The petiole shape varies from cylindric in A. americana, A. sensitiva and A. fluminensis, to triangular in A. evenia and quadrangular in A. rudis, A. denticulata and A. ciliata. We observed four types of trichomes: hydathode trichome, long conic trichome, short conic trichome and bulb-based trichome. The hydathode trichome was the most common, except for A. americana and A. fluminensis. Species with higher affinity with water share similar adaptive characteristics, including hydathode trichomes described for the first time for the genus. This article adds unseen descriptions for the genus and on the adaptation factors of the amphibious species

Analysis of pesticide residues in sugarcane juice using QuEChERS sample preparation and gas chromatography with electron capture detection

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)QuEChERS sample preparation was used for the determination of 7 pesticides residues in 80 samples of sugarcane juice collected from two Brazilian cities, in two different periods. The method involved extraction with acetonitrile, liquid-liquid partition with addition of MgSO(4) and NaCl followed by dispersive SPE cleanup with PSA sorbent and the analyses were carried out with a GC-ECD equipment. The method was validated using sugarcane juice spiked at 0.025, 0.10 and 0.20 mg/L and the average recovery by the method varied from 62.9% to 107.5% with RSDs < 18%. The method showed good linearity and the LODs for the pesticides studied ranged from 0.003 to 0.04 mg/L No pesticide residue was detected (>LOD) amongst the 80 samples analysed. (C) 2010 Elsevier Ltd. All rights reserved.126312831287Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Aspergillus niger beta-Glucosidase Has a Cellulase-like Tadpole Molecular Shape INSIGHTS INTO GLYCOSIDE HYDROLASE FAMILY 3 (GH3) beta-GLUCOSIDASE STRUCTURE AND FUNCTION

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Background: -Glucosidase completes cellulose enzymatic hydrolysis by releasing glucose from cellobiose. Results: SAXS experiments revealed that Aspergillus niger -glucosidase has a cellulase-like tadpole molecular shape, uncommon to enzymes that act on the soluble substrates. Conclusion: We show that AnBgl1 N- and C-terminal domains are linked by a long extended linker. Significance: Understanding AnBgl1 architecture is useful for comprehension of the enzyme-cell wall interaction and the process of biomass saccharification. Aspergillus niger is known to secrete large amounts of -glucosidases, which have a variety of biotechnological and industrial applications. Here, we purified an A. niger -glucosidase (AnBgl1) and conducted its biochemical and biophysical analyses. Purified enzyme with an apparent molecular mass of 116 kDa forms monomers in solution as judged by native gel electrophoresis and has a pI value of 4.55, as found for most of the fungi of -glucosidases. Surprisingly, the small angle x-ray experiments reveal that AnBgl1 has a tadpole-like structure, with the N-terminal catalytic domain and C-terminal fibronectin III-like domain (FnIII) connected by the long linker peptide (approximate to 100 amino acid residues) in an extended conformation. This molecular organization resembles the one adopted by other cellulases (such as cellobiohydrolases, for example) that frequently contain a catalytic domain linked to the cellulose-binding module that mediates their binding to insoluble and polymeric cellulose. The reasons why AnBgl1, which acts on the small soluble substrates, has a tadpole molecular shape are not entirely clear. However, our enzyme pulldown assays with different polymeric substrates suggest that AnBgl1 has little or no capacity to bind to and to adsorb cellulose, xylan, and starch, but it has high affinity to lignin. Molecular dynamics simulations suggested that clusters of residues located in the C-terminal FnIII domain interact strongly with lignin fragments. The simulations showed that numerous arginine residues scattered throughout the FnIII surface play an important role in the interaction with lignin by means of cation- stacking with the lignin aromatic rings. These results indicate that the C-terminal FnIII domain could be operational for immobilization of the enzyme on the cell wall and for the prevention of unproductive binding of cellulase to the biomass lignin.288463299133005Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Instituto Nacional de Ciencia e Tecnologia do BioetanolFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [08/56255-9, 09/54035-4, 10/16542-9]CNPq [490022/2009-0

The characterization of a thermostable and cambialistic superoxide dismutase from Thermus filiformis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The superoxide dismutase (TfSOD) gene from the extremely thermophilic bacterium Thermus filiformis was cloned and expressed at high levels in mesophilic host. The purified enzyme displayed approximately 25 kDa band in the SDS-PAGE, which was further confirmed as TfSOD by mass spectrometry. The TfSOD was characterized as a cambialistic enzyme once it had enzymatic activity with either manganese or iron as cofactor. TfSOD showed thermostability at 65, 70 and 80 degrees C. The amount of enzyme required to inhibit 50% of pyrogallol autoxidation was 0 center dot 41, 0 center dot 56 and 13 center dot 73mg at 65, 70 and 80 degrees C, respectively. According to the circular dichroism (CD) spectra data, the secondary structure was progressively lost after increasing the temperature above 70 degrees C. The 3-dimensional model of TfSOD with the predicted cofactor binding corroborated with functional and CD analysis. Significance and Impact of the Study This manuscript describes the expression and characterization of a superoxide dismutase (SOD) from Thermus filiformis with thermophilic and cambialistic characteristics. The SODs are among the most potent antioxidants known in nature, and their stability and pharmacokinetics can vary widely in accordance to their biological source. Although the currently clinical research work has been focused on human and bovine SODs, alternative sources may become more biotechnological attractive in the near future. Our study brings new insights for the research field of antioxidant enzymes with potential application on pharmaceutical, cosmetics and food formulations.5714046Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [474022/2011-4, 310177/2011-1, 142685/2010-0, 131992/2012-0]FAPESP [2008/58037-9, 2011/17658-3