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Estudo funcional comparativo das co-chaperonas moleculares p23A e p23B da Hsp90 de Leishmania braziliensis
(Universidade Federal de São Carlos, 2014-06-03) Almeida, Glessler Silva; Borges, Júlio Cesar; https://lattes.cnpq.br/6033516785481779; https://lattes.cnpq.br/2145080389866509
Protein folding is essential for proteins proper biological function. Failures in this process can lead to the formation of poorly unfolded proteins and/or protein aggregates. In order to avoid this problem, the cells express a family of proteins known as molecular chaperones. The molecular chaperones are proteins that assist the correct folding of other proteins, and other important functions in the cells. The Hsp90 family is important for protein folding and it assists in preventing protein aggregation. Hsp90 is regulated by several co-chaperones, for example, p23. The p23 is a small acidic protein that regulates the ATPase activity of Hsp90. It has a structured N-terminal beta-sheet and an unstructured C-terminal domain. In addition to the regulatory role, as an inhibitor of ATPase activity of Hsp90, it also has chaperone activity in itself. Thus, the aim of this study was to investigate comparatively two p23 identified in the Leishmania braziliensis (Lbp23A and Lbp23B) genome. The proteins were expressed, purified and structurally and functionally characterized. Furthermore, functional assays such as intrinsic chaperone activity and inhibition of ATPase activity of Hsp90 L. braziliensis (LbHsp90) and identifying in vivo by western blotting were developed. The results indicate that these two proteins are structurally similar, however, demonstrated significant differences in chemical and thermal stability. The Lbp23 also differ in relation to chaperone activity and inhibition of ATPase activity of LbHsp90. The in vivo identification revealed the presence of both Lbp23 in extracts of L. braziliensis; besides suggesting possible post-translational modifications in Lbp23B. The results indicate that both Lbp23 are undoubtedly p23, since they show p23-like function and structural signs.
Fenologia de espécies ornitófilas e ornitocóricas em um trecho de Floreta Atlântica
(Universidade Federal de São Carlos, 2014-06-03) Grimaldi, Mariana Castanheira; Piña-Rodrigues, Fátima Conceição Márquez; https://lattes.cnpq.br/1475369713141675; https://lattes.cnpq.br/8554289165234686
Phenology of Atlantic Forest is still ongoing issue for environmental studies. The goal of our study was to analyze and evaluate the phenology of plants pollinated and dispersed by birds on a stretch of Brazilian Atlantic Forest, in Carlos Botelho State Park (PECB) ( 24 ° 06 ' 55'' , 24 º 14' 41'' S , 47 º 47 ' 18'' and 48 º 07' 17'' W), whose climate has no distinct seasons. We hypothesized that there would be more flowers and fruits in warm period, in every community, and that would be synchrony between individuals of the same guild, regardless of the life-form. We selected five transects totaling 3000 m2, in which were collected phenological data of plant community from October 2012 to December 2013. According plants showed reproductive phenology, these were marked and monitored monthly. The plants were identified and categorized by life forms and dispersal and pollination syndromes. We calculated the diameter at breast height (DBH) and basal area by measuring the circumference at breast height (PAP) of trees, shrubs and palms with reproductive phenological event and all individuals larger than 15 cm DBH. We found 819 individuals with reproductive phonological event, which 68.6% were epiphytes and 23.2 % were small trees, shrubs and palm trees. The most observations of events in trees, small trees, shrubs and palm trees were smaller than 12 cm of DBH, which means high proportion of events in the understory (77,4 % of total of these four life form). Reproductive phenological events were correlated mainly with temperature and day length. Ornithophilous individuals accounted for 43.7 % of total records, and bird-dispersed plants represented 20.7%. The differences of ornithophilous flowers and bird-dispersed plant with ripe fruits between warm and cold periods of the occurrence were not significant for both (p=0,2856 e p=0,1606, respectively). The synchrony index of the occurrence of ornithophilous flowers and ripe fruit in bird-dispersal plants was low for both (Z=0.2684 and Z=0.2430, respectively). This low synchrony can avoid competition and promote pollination and dispersal. It is also noticed that in conservation areas where diversity is high, production of flowers and fruits occurs all year, offering resources any time.
Síntese e estudo das propriedades fotoluminescentes e fotocatalíticas dos cristais de Ag2-2xMxWO4, (M = Mg e Zn)
(Universidade Federal de São Carlos, 2014-06-03) Lemos, Pablo Santana; Longo, Elson; https://lattes.cnpq.br/9848311210578810; lattes.cnpq.br/5312788618871270
This study aimed to investigate the photoluminescence and photocatalytic properties of the alpha phase of silver tungstate ( α-Ag2WO4 ) doped with Mg and Zn (where M = Mg or Zn and x = 0; 0,01; 0,02; 0,04 ou 0,08). The crystals were synthesized by precipitation and were later heat treated in a hydrothermal system heated by microwave. The crystals were characterized structurally by X-ray diffraction, Rietveld refinement and by Raman scattering spectroscopy and absorption in the infrared region. From these characterizations was observed the formation of a single phase in all cases even for doping of 8%. The morphology was analyzed by SEM, and it was possible to observe changes in form and average particle size. Concerning the optical properties, these were investigated by ultraviolet- visible (UV-vis) electronic spectroscopy, and photoluminescence measurements at room temperature. In the case of UV-vis spectroscopy was observed that the substitution of Ag+ cations by Mg2+ can cause small changes in the optical band gap energy (Egap) of the materials. With respect to photoluminescence, no significant changes were observed in the profile of the emission band between the pure and doped materials. Finally, photocatalytic experiments were conducted with the crystals in the presence of rhodamine B. The analyzes of this experiment indicated that all samples exhibit photocatalytic activity in decolorization of the Rhodamine B. It might also be noted that all the doped samples showed a higher rate of discoloration of rhodamine B than the pure Ag2WO4. The kinetics for all reactions corresponds to a pseudo first order reaction.