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Search Results: 1 - 10 of 250890 matches for " Cleydson Breno R. Santos "
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A SAR and QSAR Study of New Artemisinin Compounds with Antimalarial Activity
Cleydson Breno R. Santos,Josinete B. Vieira,Cleison C. Lobato,Lorane I. S. Hage-Melim,Raimundo N. P. Souto,Clarissa S. Lima,Elizabeth V. M. Costa,Davi S. B. Brasil,Williams Jorge C. Macêdo,José Carlos T. Carvalho
Molecules , 2014, DOI: 10.3390/molecules19010367
Abstract: The Hartree-Fock method and the 6-31G** basis set were employed to calculate the molecular properties of artemisinin and 20 derivatives with antimalarial activity. Maps of molecular electrostatic potential (MEPs) and molecular docking were used to investigate the interaction between ligands and the receptor (heme). Principal component analysis and hierarchical cluster analysis were employed to select the most important descriptors related to activity. The correlation between biological activity and molecular properties was obtained using the partial least squares and principal component regression methods. The regression PLS and PCR models built in this study were also used to predict the antimalarial activity of 30 new artemisinin compounds with unknown activity. The models obtained showed not only statistical significance but also predictive ability. The significant molecular descriptors related to the compounds with antimalarial activity were the hydration energy (HE), the charge on the O11 oxygen atom (QO11), the torsion angle O1-O2-Fe-N2 (D2) and the maximum rate of R/Sanderson Electronegativity (RTe +). These variables led to a physical and structural explanation of the molecular properties that should be selected for when designing new ligands to be used as antimalarial agents.
Computational Analysis of Physicochemical, Pharmacokinetic and Toxicological Properties of Deoxyhypusine Synthase Inhibitors with Antimalarial Activity  [PDF]
Nayara S. R. Silva, Luana K. S. Gon?alves, Jonatas L. Duarte, Juliane S. Silva, César F. Santos, Francinaldo S. Braga, Raí C. Silva, Josivan S. Costa, Lorane I. S. Hage-Melim, Cleydson B. R. dos Santos
Computational Molecular Bioscience (CMB) , 2014, DOI: 10.4236/cmb.2014.44006
Abstract: Malaria is a parasitic disease which has as etiological agents protozoa of the genus Plasmodium prevalent in tropical countries. The appearance of Plasmodium strains resistant to artemisinin has become necessary the development of new drugs using computational tools to combat this epidemic. Diverse transporter proteins can act as antimalarials targets, thereby being the enzyme deoxyhypusine synthase a promising antimalarial target. The present study aimed to investigate 15 most active inhibitors of deoxyhypusine synthase target, deposited in databases Binding DB, in order to trace a pattern of physicochemical, pharmacokinetic and toxicological properties of the inhibitors for this enzyme and propose new inhibitors of deoxyhypusine synthase target. The physicochemical properties were obtained according to the Lipinski parameters to evaluate oral absorption. Based on the certain properties were proposed three new inhibitors (A, B and C). The ADME/Tox properties were calculated for new inhibitors compared with results of the selected compounds. The fifteen inhibitors for oral administration showed satisfactory results, because they have adapted to the Lipinski parameters. In relation to the penetration of the blood-brain barrier the inhibitors analyzed showed penetration values less than 1, and ranged from 0.0411815 to 0.481764, being that the compound 1 showed value of CBrain/CBlood = 0.135467. Compound B showed a higher strength in plasma protein binding in relation to the compound 1, having a variation be-tween them of ±1.489344. Therefore, the compound B would present a longer halflife compared with compound 1. The proposed compounds showed positive and satisfactory results, being able to reach less adverse effects related to the central nervous system depending of administered dose.
Application of Hartree-Fock Method for Modeling of Bioactive Molecules Using SAR and QSPR  [PDF]
Cleydson B. R. Santos, Cleison C. Lobato, Francinaldo S. Braga, Sílvia S. S. Morais, Cesar F. Santos, Caio P. Fernandes, Davi S. B. Brasil, Lorane I. S. Hage-Melim, Williams J. C. Macêdo, José C. T. Carvalho
Computational Molecular Bioscience (CMB) , 2014, DOI: 10.4236/cmb.2014.41001
Abstract:
The central importance of quantum chemistry is to obtain solutions of the Schr?dinger equation for the accurate determination of the properties of atomic and molecular systems that occurred from the calculation of wave functions accurate for many diatomic and polyatomic molecules, using Self Consistent Field method (SCF). The application of quantum chemical methods in the study and planning of bioactive compounds has become a common practice nowadays. From the point of view of planning it is important to note, when it comes to the use of molecular modeling, a collective term that refers to methods and theoretical modeling and computational techniques to mimic the behavior of molecules, not intend to reach a bioactive molecule simply through the use of computer programs. The choice of method for energy minimization depends on factors related to the size of the molecule, parameters of availability, stored data and computational resources. Molecular models generated by the computer are the result of mathematical equations that estimate the positions and properties of the electrons and nuclei, the calculations exploit experimentally, the characteristics of a structure, providing a new perspective on the molecule. In this work we show that studies of Highest Occupied Molecular Orbital Energy (HOMO), Low Unoccupied Molecular Orbital Energy (LUMO) and Map of molecular electrostatic potential (MEP) using Hatree-Fock method with different basis sets (HF/3-21G*, HF/3-21G**, HF/6-31G, HF/6-31G*, HF/6-31G** and HF/6-311G), that are of great importance in modern chemistry, biochemistry, molecular biology, and other fields of knowledge of health sciences. In order to obtain a significant correlation, it is essential that the descriptors are used appropriately. Thus, the quantum chemical calculations are an attractive source of new molecular descriptors that can, in principle, express all the geometrical and electronic properties of molecules and their interactions with biological receptor.
Evaluation of Quantum Chemical Methods and Basis Sets Applied in the Molecular Modeling of Artemisinin  [PDF]
Cleydson B. R. dos Santos, Cleison C. Lobato, Josinete B. Vieira, Davi S. B. Brasil, Alaan U. Brito, Williams J. C. Macêdo, José Carlos T. Carvalho, José C. Pinheiro
Computational Molecular Bioscience (CMB) , 2013, DOI: 10.4236/cmb.2013.33009
Abstract: In this paper, we evaluate semiempirical methods (AM1, PM3, and ZINDO), HF and DFT (B3LYP) in different basis sets to determine which method best describes the sign and magnitude of the geometrical parameters of artemisinin in the region of the endoperoxide ring compared to crystallographic data. We also classify these methods using statistical analysis. The results of PCA were based on three main components, explaining 98.0539% of the total variance, for the geometrical parameters C3O13, O1O2C3, O13C12C12a, and O2C3O13C12. The DFT method (B3LYP) corresponded well with the experimental data in the hierarchical cluster analysis (HCA). The experimental and theoretical angles were analyzed by simple linear regression, and statistical parameters (correlation coefficients, significance, and predictability) were evaluated to determine the accuracy of the calculations. The statistical analysis exhibited a good correlation and high predictive power for the DFT (B3LYP) method in the 6-31G** basis set.
Growth and symptomatological aspects in the acclimatization of ipê roxo
Jo?o Paulo Rodrigues Martins,Breno Régis Santos,Sandro Barbosa,Wesley Pires Flausino Máximo
CERNE , 2011,
Abstract: This work evaluated the influence of seal type and substrate type on pre-acclimatization, and symptomatological aspects relating to acclimatization of ipê-roxo. For the pre-acclimatization, ipê-roxo plants obtained through an in vitro zygotic embryo culture were aseptically inoculated in test tubes with different types of seal (cotton plug, plastic cap + parafilm and plastic lid) and different substrates (agar, vermiculite and Plantmax ) supplemented with a WPM culture medium with 1 gL-1 of activated charcoal, 10 mgL-1 of citric acid and 30 gL-1 of sucrose added. For the acclimatization, in vitro ipê-roxo plants were transplanted into 56-cm3 plastic tubes containing vermiculite and Plantmax at a 2:1 ratio which had been previously autoclaved at 121oC and 1 atm for 20 minutes. Once transplanted, the plants were irrigated with different concentrations of the MS medium (25%, 50%, 75%, 100% and 150%), using distilled water as control. After 30 days, the effects of seal type and substrate type on pre-acclimatization were examined. Cotton can be recommended where Plantmax or vermiculite is used as substrate. In the acclimatization it was noted that where plants were irrigated with distilled water and concentrations < 50% they showed symptoms of nutritional deficiency. Similar symptoms were observed when using MS medium at a concentration equal to or greater than 100%. The 75% MS concentration was found to be the most effective at maintaining the nutritional vigor of ipê-roxo seedlings in the process of acclimatization.
Indu o de calos friáveis em explantes foliares de Salix (Salyx humboldtiana Willd)
Santos Breno Régis,Paiva Renato,Martinotto Cristiano,Nogueira Raírys Cravo
Ciência Rural , 2005,
Abstract: O salix é uma árvore ornamental adaptada a terrenos úmidos, sendo considerada uma espécie importante para a recomposi o de áreas ciliares degradadas. A madeira pode ser empregada na indústria em geral. Apesar de produzir grande quantidade de sementes, estas n o possuem alta percentagem de germina o. O presente trabalho teve como objetivo realizar o estabelecimento in vitro de salix através da indu o e forma o de calos friáveis em explantes foliares, visando a uma posterior regenera o de plantas para a propaga o massal desta espécie. Explantes foliares foram inoculados em meio de cultura MS (MURASHIGE & SKOOG, 1962), acrescido de diferentes concentra es de ácido 2,4-diclorofenoxiacético (0; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0 e 12,0mg L-1) e combina es entre ácido naftalenoacético e benzilaminopurina, ambos em concentra es de 0,0; 1,0; 2,0; 4,0; 6,0 e 8,0mg L-1. Os resultados demonstram que explantes inoculados na ausência de reguladores de crescimento n o apresentam a forma o de calos friáveis. Significativa produ o de calos friáveis (90%) é obtida utilizando-se 6,0mg L-1 de ácido 2,4-diclorofenoxiacético. A utiliza o de concentra o individual de ácido naftalenoacético ou benzilaminopurina, além de induzir a calogênese também foi capaz de promover rizogênese.
Os jesuítas na Amaz nia portuguesa: a "crise de voca es" e seus reflexos na Miss o do Maranh o e Gr o-Pará
Breno Machado dos Santos
OPSIS : Revista do Departamento de História e Ciências Sociais , 2009,
Abstract: This article analyses the actuationdirectives of the Jesuits in activity in Estate ofMaranh o and Gr o-Pará in the seventeenthcentury.Furthermore, it proposes to relate thesmall number of religious in the Mission withthe crisis of the apostolic vocation experiencedby the Order in Estate of Brazil. Thus, it isintend to give light on the reflections of thedualism existent inside the Society of Jesus dueto the option for the indian Missions or betweenthe activities related to the Schools of Order.
A miss o como representa o: os jesuítas no Maranh o e Gr o-Pará através das cartas do Padre Ant nio Vieira / The mission as representation: the Jesuits in Maranh o and Gr o-Pará through the letters of Father Ant nio Vieira
Breno Machado dos Santos
Plura : Revista de Estudos de Religi?o , 2011,
Abstract: Based on the theoretical and methodological formulations presented by Roger Chartier, this article aims to work on the representations built by father Ant nio Vieira on the Jesuits in activity in the State of Maranh o and Gr o-Pará. In order to arouse new vocations, Vieira projects the apostolate in the North of Province as the Order’s most difficult and important ones, destined to religious imbued with a high leveled missionary spirit. In this process, the Ignatian forge a fight of representations in his argumentativeschemes, revealing in his letters the existence of a deep differentiation in the Jesuits’ modus procedendi which allows us to relate the shortage of religious in the region to a vocation crisis experienced by the Society of Jesus.Através das formula es teórico-metodológicas apresentadas por Roger Chartier, este artigo almeja trabalhar sobre as representa es construídas pelo padre Ant nio Vieira em torno dos inacianos em atividade no Estado do Maranh o e Gr o-Pará. No intuito de suscitar novas voca es, Vieira projeta o apostolado no Norte da Província como um dos mais difíceis e importantes da Ordem, destinado a religiosos imbuídos de um elevado espírito missionário. Neste processo, o inaciano forja uma luta de representa es em seus esquemas argumentativos, revelando em suas missivas a existência de uma profunda diferencia o em rela o ao modus procedendi dos jesuítas que nos permite tentar relacionar a escassez de religiosos na regi o à crise de voca es vivenciada pela Companhia de Jesus.
Indu??o de calos friáveis em explantes foliares de Salix (Salyx humboldtiana Willd)
Santos, Breno Régis;Paiva, Renato;Martinotto, Cristiano;Nogueira, Raírys Cravo;Paiva, Patrícia Duarte de Oliveira;
Ciência Rural , 2005, DOI: 10.1590/S0103-84782005000300004
Abstract: salix is an ornamental tree adapted to humid soils being considered an important species used in depleted areas. its wood may be used in all kinds of industries. although the production of seeds is large, the germination is reduced. the objective of this work was to establish salix in vitro through the induction and formation of friable callus of leaf explants to provide future regeneration of plants for mass propagation of the species. leaf explants were inoculated in ms medium (murashige & skoog, 1962) supplemented with different concentrations of 2-4-diclorofenoxiacetic acid (0; 1.0; 2.0; 4.0; 6.0; 8.0 and 12.0mg l-1) and combinations of 1-naphthaleneacetic acid and 6-benzylaminopurine both with the concentrations of 0; 1.0; 2.0; 4.0; 6.0 e 8.0mg l-1. the results showed that explants inoculated in the absence of growth regulators had no formation of friable callus. significant production of friable callus (90%) was obtained with 6.0mg l-1 of 2-4-diclorofenoxiacetic acid. individual concentrations of 1-naphthaleneacetic acid or 6-benzylaminopurine induced callogenesis and rooting.
Efeito da escarifica??o e luminosidade na germina??o in vitro de sementes de cagaiteira (Eugenia dysenterica DC.)
Martinotto, Cristiano;Paiva, Renato;Santos, Breno Régis;Soares, Fernanda Pereira;Nogueira, Raírys Cravo;Silva, álvaro Augusto Naves;
Ciência e Agrotecnologia , 2007, DOI: 10.1590/S1413-70542007000600010
Abstract: cagaiteira is a native specie of brazilian cerrado with high yield. because it seeds show high variability, it is yet considered recalcitrant and dormant, the germination in vitro appears as an alternative for specie propagation, in addition to obtain juvenile explant for micropropagation. the present research aimed to evaluate the effect of scarification and ligth on germination in vitro of cagaiteira seeds. seeds without teguments and intact seeds were inoculated in ms medium and kept in abscence and presence of radiation. seeds without tegument germinated in the presence or abscence of ligth showed 86.25% and 88.25% germination at 31 and 71 days of inoculation, respectively. after 150 days of inoculation, plantlets from seeds without tegument germinated in the presence and abscence of ligth, showed 10% and 12% of abnormalities, respectively.
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