Institution
Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto
Education•
About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Genus. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.
Topics: Population, Genus, Catalysis, Ruthenium, Elevated plus maze
Papers published on a yearly basis
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TL;DR: The stability studies showed that the samples were stable during freeze and thaw cycles, short-term exposure to room temperature, storage at −20 °C, and biotransformation conditions, and the coefficients of variation and relative errors obtained in precision and accuracy studies were below 15%.
Abstract: The purpose of this study was the development and validation of an LC–MS–MS method for simultaneous analysis of ibuprofen (IBP), 2-hydroxyibuprofen (2-OH-IBP) enantiomers, and carboxyibuprofen (COOH-IBP) stereoisomers in fungi culture medium, to investigate the ability of some endophytic fungi to biotransform the chiral drug IBP into its metabolites. Resolution of IBP and the stereoisomers of its main metabolites was achieved by use of a Chiralpak AS-H column (150 × 4.6 mm, 5 μm particle size), column temperature 8 °C, and the mobile phase hexane–isopropanol–trifluoroacetic acid (95: 5: 0.1, v/v) at a flow rate of 1.2 mL min−1. Post-column infusion with 10 mmol L−1 ammonium acetate in methanol at a flow rate of 0.3 mL min−1 was performed to enhance MS detection (positive electrospray ionization). Liquid–liquid extraction was used for sample preparation with hexane–ethyl acetate (1:1, v/v) as extraction solvent. Linearity was obtained in the range 0.1–20 μg mL−1 for IBP, 0.05–7.5 μg mL−1 for each 2-OH-IBP enantiomer, and 0.025–5.0 μg mL−1 for each COOH-IBP stereoisomer (r ≥ 0.99). The coefficients of variation and relative errors obtained in precision and accuracy studies (within-day and between-day) were below 15%. The stability studies showed that the samples were stable (p > 0.05) during freeze and thaw cycles, short-term exposure to room temperature, storage at −20 °C, and biotransformation conditions. Among the six fungi studied, only the strains Nigrospora sphaerica (SS67) and Chaetomium globosum (VR10) biotransformed IBP enantioselectively, with greater formation of the metabolite (+)-(S)-2-OH-IBP. Formation of the COOH-IBP stereoisomers, which involves hydroxylation at C3 and further oxidation to form the carboxyl group, was not observed.
33 citations
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TL;DR: Optical and structural properties of planar and channel waveguides based on sol-gel Er3+ and Yb3+ co-doped SiO2-ZrO2 are reported in this paper.
33 citations
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TL;DR: Results indicate that biomimetic oxidation reactions, in addition to in vitro metabolism assays employing isolated organs/organelles, could replace some in vivo metabolism studies, thus minimizing the problems related to the use of a large number of living animals in experimental research.
33 citations
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TL;DR: The decreasing order of Gibbs free energy change at 328K correlates well with the thermotolerance results, and is dominated by changes in ΔHND which is consistent with increased in hydrogen bonding in the thermostable mutants.
33 citations
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TL;DR: The first structural characterization of nucleoside diphosphate kinases b from trypanosomatid parasites (tNDKbs) is described providing insights into their oligomerization, stability and structural determinants for nucleotide binding.
Abstract: Nucleoside diphosphate kinases play a crucial role in the purine-salvage pathway of trypanosomatid protozoa and have been found in the secretome of Leishmania sp., suggesting a function related to host-cell integrity for the benefit of the parasite. Due to their importance for housekeeping functions in the parasite and by prolonging the life of host cells in infection, they become an attractive target for drug discovery and design. In this work, we describe the first structural characterization of nucleoside diphosphate kinases b from trypanosomatid parasites (tNDKbs) providing insights into their oligomerization, stability and structural determinants for nucleotide binding. Crystallographic studies of LmNDKb when complexed with phosphate, AMP and ADP showed that the crucial hydrogen-bonding residues involved in the nucleotide interaction are fully conserved in tNDKbs. Depending on the nature of the ligand, the nucleotide-binding pocket undergoes conformational changes, which leads to different cavity volumes. SAXS experiments showed that tNDKbs, like other eukaryotic NDKs, form a hexamer in solution and their oligomeric state does not rely on the presence of nucleotides or mimetics. Fluorescence-based thermal-shift assays demonstrated slightly higher stability of tNDKbs compared to human NDKb (HsNDKb), which is in agreement with the fact that tNDKbs are secreted and subjected to variations of temperature in the host cells during infection and disease development. Moreover, tNDKbs were stabilized upon nucleotide binding, whereas HsNDKb was not influenced. Contrasts on the surface electrostatic potential around the nucleotide-binding pocket might be a determinant for nucleotide affinity and protein stability differentiation. All these together demonstrated the molecular adaptation of parasite NDKbs in order to exert their biological functions intra-parasite and when secreted by regulating ATP levels of host cells.
33 citations
Authors
Showing all 2195 results
Name | H-index | Papers | Citations |
---|---|---|---|
Jon Lloyd | 80 | 230 | 30995 |
Peter C. Ford | 74 | 495 | 20821 |
Frederico Guilherme Graeff | 60 | 183 | 12209 |
Marcus Lira Brandão | 54 | 243 | 9248 |
David W. Roubik | 54 | 177 | 10070 |
Richard J. Ward | 53 | 242 | 9502 |
Juan Cornejo | 49 | 147 | 6478 |
Norberto Peporine Lopes | 47 | 457 | 12031 |
Carlos Alemán | 47 | 634 | 11349 |
Klaus Hartfelder | 45 | 150 | 7708 |
Valtencir Zucolotto | 45 | 212 | 6253 |
Rosane Marina Peralta | 44 | 212 | 5701 |
Antonio Claudio Tedesco | 44 | 307 | 6778 |
Roberto M. Torresi | 44 | 213 | 5822 |
Zilá Luz Paulino Simões | 43 | 113 | 8020 |