Navegando por Autor "Ferreira, Joana Gasperazzo"
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Item Hydrolysis of galacto-oligosaccharides in soy molasses by α -galactosidases and invertase from Aspergillus terreus(Brazilian Archives of Biology and Technology, 2010-05) Reis, Angélica Pataro; Guimarães, Valéria Monteze; Ferreira, Joana Gasperazzo; Queiroz, José Humberto de; Oliveira, Maria Goreti Almeida; Falkoski, Daniel Luciano; Almeida, Maíra Nicolau de; Rezende, Sebastião Tavares deTwo α -galactosidase (P1 and P2) and one invertase present in the culture of Aspergillus terreus grown on wheat straw for 168 h at 28ºC were partially purified by gel filtration and hydrophobic interaction chromatographies. Optimum pH and temperatures for P1, P2 and invertase preparations were 4.5-5.0, 5.5 and 4.0 and 60, 55 and 65ºC, respectively. The KM app for ρ -nitrophenyl-α -D-galactopyranoside were 1.32 mM and 0.72 mM for P1 and P2, respectively, while the KM app value for invertase, using sacarose as a substrate was 15.66 mM. Enzyme preparations P1 and P2 maintained their activities after pre-incubation for 3 h at 50ºC and invertase maintained about 90% after 6 h at 55 ºC. P1 and P2 presented different inhibition sensitivities by Ag+, D-galactose, and SDS. All enzyme preparations hydrolyzed galacto-ologosaccharides present in soymolasses.Item Potential antileukemia effect and structural analyses of SRPK inhibition by N-(2- (Piperidin-1-yl)-5-(Trifluoromethyl)Phenyl) isonicotinamide (SRPIN340)(Plos One, 2014-04-08) Siqueira, Raoni Pais; Barbosa, Éverton de Almeida Alves; Polêto, Marcelo Depólo; Righetto, Germanna Lima; Seraphim, Thiago Vargas; Salgado, Rafael Locatelli; Ferreira, Joana Gasperazzo; Oliveira, Leandro Licursi de; Laranjeira, Angelo Brunelli Albertoni; Almeida, Márcia Rogéria; Fietto, Juliana Lopes Rangel; Kobarg, Jörg; Oliveira, Eduardo Basílio de; Teixeira, Robson Ricardo; Borges, Júlio César; Silva Júnior, Abelardo; Bressan, Gustavo Costa; et al.Dysregulation of pre-mRNA splicing machinery activity has been related to the biogenesis of several diseases. The serine/arginine-rich protein kinase family (SRPKs) plays a critical role in regulating pre-mRNA splicing events through the extensive phosphorylation of splicing factors from the family of serine/arginine-rich proteins (SR proteins). Previous investigations have described the overexpression of SRPK1 and SRPK2 in leukemia and other cancer types, suggesting that they would be useful targets for developing novel antitumor strategies. Herein, we evaluated the effect of selective pharmacological SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, we found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. These data suggest that SRPK pharmacological inhibition should be considered as an alternative therapeutic strategy for fighting leukemias. Moreover, the obtained SRPK-ligand interaction data provide useful structural information to guide further medicinal chemistry efforts towards the development of novel drug candidates.Item Purificação parcial e caracterização bioquímico-cinética de α-galactosidase de Aspergillus terreus(Universidade Federal de Viçosa, 2007-02-28) Ferreira, Joana Gasperazzo; Ribon, Andréa de Oliveira Barros; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4727026E6; Oliveira, Maria Goreti de Almeida; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790894D6; Queiroz, José Humberto de; http://lattes.cnpq.br/4881556650652069; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4737746E6; Fietto, Juliana Lopes Rangel; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790238D0; Pereira, Maria Cristina Baracat; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780021E6A α-galactosidase apresenta grande capacidade para hidrólise de ligações α-1,6 nos oligossacarídeos de galactose (GO) como a rafinose [O-α-Dgalactopiranosil-(1→6)-D-glicopiranosil-(1→2)-β-D-frutofuranosídeo]. Esses açúcares estão presentes nas sementes de soja, e são responsáveis por distúrbios gastrintestinais relacionados com a ingestão de produtos derivados de soja, devido a ausência da enzima α-galactosidase na mucosa intestinal de humanos e animais monogástricos. Dessa forma, a hidrólise dos GO de produtos de soja poderá contribuir para melhorar o seu valor nutritivo. O objetivo desse trabalho foi produzir, purificar e caracterizar uma isoforma extracelular da α-galactosidase do fungo Aspergillus terreus, e avaliar a capacidade da enzima em promover a redução ou eliminação dos oligossacarídeos de galactose presentes em leite de soja. O fungo A. terreus foi cultivado em meio mineral líquido contendo farelo de trigo como fonte de carbono por 7 dias a 28 °C. O extrato enzimático foi submetido à cromatografia em resinas de Sephacryl S-200, Phenyl-Sepharose e DEAE-Sephacel. A última etapa de purificação resultou na enzima parcialmente purificada com um fator de purificação de 26,96 vezes e um rendimento de 19,07%. A massa molecular da enzima foi estimada por eletroforese desnaturante (SDS-PAGE 12,5%) e por cromatografia de exclusão molecular em Sephacryl S-200, de 50 kDa e 77,3 kDa, respectivamente. Atividade máxima da α-galactosidase foi determinada em pH 5,0 e 55 °C. Quando a enzima foi incubada por 6 horas no intervalo de pH 4 6, ela manteve mais de 90% da atividade inicial. A α-galactosidase de A. terreus a 50 °C perdeu 39% de sua atividade após 151 horas de incubação. Na temperatura de 55 °C a enzima conservou 33% de sua atividade após 52 horas de incubação. A 60 °C, a enzima manteve 92% da atividade inicial por 30 minutos. Na temperatura de 55 °C a meia-vida da enzima foi de 35 horas e a 60 °C de 103 minutos. Para os substratos sintéticos, a enzima demonstrou ser muito seletiva, apresentando maior afinidade pelo substrato ρ-NP-αGal. A enzima hidrolisou os substratos naturais melibiose, estaquiose e rafinose, apresentando também capacidade de hidrolisar os polímeros goma guar e goma locusta. O valor de KM ap para o substrato ρ-NP-αGal foi de 0,75 mM, para a melibiose de 7,39 mM, para a rafinose de 32,99 mM e para a estaquiose de 54,74 mM. A atividade enzimática foi totalmente perdida em presença de Ag+ e parcialmente perdida quando em presença de Cu2+ e galactose. Na presença do substrato ρ-NP-αGal a enzima foi inibida competitivamente por galactose (Ki 0,61 mM). A energia de ativação foi calculada para os substratos ρ-NP-αGal (65,85 kJ/mol), melibiose (39,77 kJ/mol), rafinose (42,98 kJ/mol) e estaquiose (47,27 kJ/mol). A enzima α-galactosidase de A. terreus não converteu o sangue tipo B em tipo O. Após 12 horas de incubação da α-galactosidase purificada com leite de soja a 50 °C, pode-se observar que a enzima hidrolisou 100 % da rafinose e 60,3 % da estaquiose, mostrando que a α-galactosidase de A. terreus foi eficiente na redução de GO presentes no leite de soja.Item Purification and characterization of Aspergillus terreus α-Galactosidases and their use for hydrolysis of Soymilk Oligosaccharides(Applied Biochemistry and Biotechnology, 2011-02-18) Ferreira, Joana Gasperazzo; Reis, Angélica Pataro; Guimarães, Valéria Monteze; Falkoski, Daniel Luciano; Silva Fialho, Lílian da; Rezende, Sebastião Tavares deα-Galactosidases has the potential to hydrolyze α-1-6 linkages in raffinose family oligosaccharides (RFO). Aspergillus terreus cells cultivated on wheat bran produced three extracellular forms of α-galactosidases (E1, E2, and E3). E1 and E2 α-galactosidases presented maximal activities at pH 5, while E3 α-galactosidase was more active at pH 5.5. The E1 and E2 enzymes showed stability for 6 h at pH 4–7. Maximal activities were determined at 60, 55, and 50°C, for E1, E2, and E3 α-galactosidase, respectively. E2 α-galactosidase retained 90% of its initial activity after 70 h at 50°C. The enzymes hydrolyzed ρNPGal, melibiose, raffinose and stachyose, and E1 and E2 enzymes were able to hydrolyze guar gum and locust bean gum substrates. E1 and E3 α-galactosidases were completely inhibited by Hg2+, Ag+, and Cu2+. The treatment of RFO present in soy milk with the enzymes showed that E1 α-galactosidase reduced the stachyose content to zero after 12 h of reaction, while E2 promoted total hydrolysis of raffinose. The complete removal of the oligosaccharides in soy milk could be reached by synergistic action of both enzymesItem Synthesis and antiproliferative activity of C-3 functionalized Isobenzofuran-1(3H)-ones(Molecules, 2013-02-01) Teixeira, Róbson Ricardo; Bressan, Gustavo Costa; Pereira, Wagner Luiz; Ferreira, Joana Gasperazzo; Oliveira, Fabrício Marques de; Thomaz, Deborah CamposA series of thirteen C-3 functionalized isobenzofuran-1(3H)-ones (phtalides) was synthesized via condensation, aromatization, and acetylation reactions. NMR (one and two dimensional experiments), IR, and mass spectrometry analysis allowed confirmation of the identity of the synthesized compounds. The substances were submitted to in vitro bioassays against U937 (lymphoma) and K562 (myeloid leukemia) cancer cell lines using the MTT cytotoxicity assay. Some derivatives inhibited 90% of cell viability at 100 µM. Also, two phtalides presented biological activity superior than that of etoposide (VP16), a commercial drug used as a positive control in the assays. In silico drug properties of the evaluated compounds were calculated and the results are discussed.Item Synthesis, molecular properties prediction and cytotoxic screening of 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones(Elsevier Bioorganic & Medicinal Chemistry Letters, 2016-04-25) Maia, Angélica Faleiros da Silva; Siqueira, Raoni Pais; Oliveira, Fabrício Marques de; Ferreira, Joana Gasperazzo; Silva, Silma Francielle da; Caiuby, Clarice Alves Dale; Oliveira, Leandro Licursi de; Paula, Sérgio Oliveira de; Souza, Rafael Aparecido Carvalho; Guilardi, Silvana; Bressan, Gustavo Costa; Teixeira, Róbson RicardoIn the present investigation, a collection of nineteen 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones was synthesized and screened for their cytotoxic activity against a panel of three leukemia cancer cell lines. The compounds were prepared via ZrOCl2·8H2O catalyzed condensation reactions between phthalaldehydic acid and different acetophenones. The reactions were carried out free of solvent and the isobenzofuran-1(3H)-ones were obtained in good yields (80–92%). The identities of the synthesized compounds were confirmed upon IR and NMR (1H and 13C) spectroscopy as well as high resolution mass spectrometry analyses. Structures of compounds 1, 4 and 16 were also investigated by X-ray analysis. The synthesized compounds were submitted to in vitro bioassays against HL-60, K562 and NALM6 cancer cell lines using MTT cytotoxicity assay. After 48 h of treatment, twelve derivatives were able to reduce cell viability and presented IC50 values equal to or below 20 μmol L−1 against at least one of the evaluated lineages. The most active compound corresponded to 3-(3-methylphenyl-2-oxoethyl)isobenzofuran-1(3H)-one (18) (IC50 values obtained for HL-60, K562 and NALM6 were, respectively, 13.5 μmol L−1, 8.83 μmol L−1, and 5.24 μmol L−1). In addition, compound 18 was capable of triggering apoptosis on NALM6 cells. All isobenzofuranones herein evaluated did not present cytotoxicity on peripheral blood mononuclear cells (PBMC), suggesting selective cytotoxic effect on leukemic cells. A computational study allowed prediction of pharmacokinetics and drug-likeness properties of the synthesized compounds. DFT calculations were performed to obtain the energy values of HOMO, LUMO, and dipole moments of isobenzofuranones.