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Fitoquímica de Raputia praetermissa (Rutaceae) e busca por candidatos a herbicidas inibidores da fotossíntese a partir de produtos naturais
(Universidade Federal de São Carlos, 2008-04-18) Veiga, Thiago André Moura; Silva, Maria Fátima das Graças Fernandes da; https://lattes.cnpq.br/0457632122660653; https://lattes.cnpq.br/8190975614526360
The species R. praetermissa is native from Amazonia. Plant recently classified, it does not give biological and/or chemical in the literature. This fact has led to this study, which can lead to the correct chemosystematic positioning of the genus within the family Rutaceae. From the phytochemical study of the roots of R. praetermissa concluded in 2005, mainly were found alkaloids derived from tryptophan and limonoids. The second step was the phytochemical study of some fractions of the dichloromethane extract of the roots and the extracts of the stem and leaves of the species. Alkaloids have been isolated and identified (indole, furoquinolines and quinolones), triterpenes (cycloartanes and friedelanes), steroids and a derivative of cinnamic acid. Among the substances found can highlight four substances not reported in the literature: two alkaloids, a diterpene and the derivative of cinnamic acid. A collection of 120 natural products isolated by the group of Natural Products/UFSCar was subjected to a series of enzymatic reactions that explained the mechanism of action of the substances considered active against photosynthesis in vitro in chloroplasts isolated from the leaves of spinach. It was possible to clarify the mechanism of action of 30 substances, which allowed so far, the publication of articles in indexed international journals and conferences (nationals and internationals). The prospects are quite interesting, especially as regards the implementation of this new line of research, not only in the Department of Chemistry (UFSCar), but also in Brazil, so that later are found models for new herbicides inhibitors of photosynthesis.
Estudo mecânico-quântico ab initio da propriedade fotoluminescente em compostos PbWO4, BaWO4, SrWO4 e dos processos de intercalação e difusão de Li no composto Li1+xTi2O4
(Universidade Federal de São Carlos, 2008-04-18) Santos, Marcos Anicete dos; Varela, José Arana; https://lattes.cnpq.br/1807399214239200; https://lattes.cnpq.br/4019009359628022
Computational simulation by means of quantum-mechanical calculations is becoming an increasingly important tool in scientific research of materiaIs due the great advances in the performance of computers and in the development of more efficient algorithms, providing a deeper understanding of nanoscale mechanisms which often cannot be detected directly by the experimental measures. The development of materiaIs with efficient optical properties is of great industrial interest. The photoluminescence (PL), one important optical property, has been intensively explored in scientific optical research and in technological applications. The literature presents that the most intense PL emissions of the compounds PbWO4, Ba WO4 and SrWO4 is favored by structural disorder in its lattice. Results of computeI simulations of structurally disordered compounds PbWO4, BaWO4 and SrWO4 by means of quantum-mechanical ab initio calculations were presented in this thesis, in arder to interpret why these disordered structures favor the most intense PL emissions. The calculations indicated that these structurally disordered compounds favor intense PL emissions because contain non-homogeneous distribution of charges in its lattice causing the generation of trapped electronic boles, thus, providing electron-hole recombinations to intense and broad PL emissions. The progress of research in batteries based on lithium-ion (Li batteries) has aIso great technological importance due the commercial demand of portable devices. In particular the compound Li1+xTi2O4 (O ≤X ≤ 1) is a perspective material for application in Li batteries due to its high fatia energy storagejweight. Results of computational simulations using quantum-mechanical ab initio calculations in processes of Li intercalation and diffusion in the structure Li1+xTi2O4 (0 ≤ X ≤ 0.375) were also presented in this work, in arder to identify the most favorable migration paths of considered different concentrations, and that such identification is not experimentally possible. The calculations of the processes of Li intercalation and diffusion in the structure Li1+xTi2O4 indicate that the Li insertion is energetically favorable in alI range of concentration x studied and the Li migration are favorable only for x 2: 0.25. Quantum-mechanical calculations aIso indicate the more favorable migration paths for each concentration x considered, and that migration of lithium is more favorable in less stable local Li arrangements because the energy cost for lithium migrating in more stable arrangements is greater than the energy cost for lithium migrating in less stable arrangements.
Análise da expressão da metalotioneína em duas espécies de peixes, Oreochromis niloticus e Prochilodus lineatus
(Universidade Federal de São Carlos, 2008-04-18) Coimbra, Thaissa de Melo Galante; Araújo, Heloísa Sobreiro Selistre de; https://lattes.cnpq.br/4065824911933203; https://lattes.cnpq.br/6730831006126304
Metallothioneins (MT) are non enzymatic proteins with with metal-binding ability. It has been used as a biomarker for environmental pollution by the analysis of its expression in several fish species. The tilapia is a commonly used model in studies of animal toxicology and some of these species have a well characterized MT sequence. Here, the Oreochromis niloticus specie was used in the standardization of the MT expression assay. The Prochilodus lineatus species is widely distributed in the Brazilian s Basins that has been studied regarding growth, illness and the toxicity of metals. However the MT DNA sequence from this species has not been described. The aim of this project was the analysis of the MT DNA in both species, O. niloticus and P. lineatus. For that, individuals from these species received intraperitoneal injections of zinc chloride, in increasing doses of 1 to 8 mg/kg for 4 days.. After this time, animals were killed and total RNA was isolated from the liver and used in an RT-PCR with primers designed accordingly to MT coding regions of fish MT deposited at www.ncbi.nlm.nih.gov. DNA sequencing confirmed the highly conserved MT sequence for both species. For quantitative analysis, cDNA was used in a similar real-time PCR with the same primers plus the fluorophore Syber Green. TheZnCl2 treatment increased MT mRNA expression about 4 times for O. niloticus and almost 35 times for P. lineatus when compared with subjects that were not exposed to the metal. This difference was statistically significant in the experiments for both species. The results indicate the high conservation of the MT gene structure, that allow the use of MT in environmental research.