SAPT: ligação de hidrogênio ou interação de van der Waals?

It is through the application of an electronic partition approach called Symmetry-Adapted Perturbation Theory (SAPT) that the nature of hydrogen bonds and van der Waals interactions can be unveiled according to the contribution of electrostatic, charge transfer, exchange repulsion, polarization, and dispersion terms. Among these, electrostatic partition governs the formation of the hydrogen bonds, whose energies are arguably high. However, the weakness of the interaction strength is caused by dispersion forces, whose contribution decisively lead to the stabilization of complexes formed via van der Waals interactions

In silico Studies Combining QSAR Models, DFT-based Reactivity Descriptors and Docking Simulations of Phthalimide Congeners with Hypolipidemic Activity

In this current study, a selected group of physicochemical descriptors extracted from the formalism of the density functional theory were used for modeling a series of phthalimide congeners with tested hypolipidemic activity once. Based on unsupervised pattern recognition of HCA and PCA followed by the PLS regressions, the final content may be considered trustful for predicting the biological activity due to the results of r2cal = 0.937, r2CV = 0.591 and r2test = 0.85. Moreover, the molecular modeling was performed through the docking protocol for predicting the ligand pose on the HMG-CoA reductase. The protocols of the AutoDock Tools and AutoDock Vina were used for determining the interaction scores (ΔG) and inhibition constants (Ki). Among all congeners studied, the docking results pointed out a potential compound. By taking into account the widely known top selling drugs, and just as is well-known that atorvastatin is one of them due its capability to lower the cholesterol levels, the structure of this drug was subjected to a docking study in order to guide us to a better understanding of the results available here. DOI: http://dx.doi.org/10.17807/orbital.v13i3.149

Automedicação na perspectiva CTS: relato de uma experiência realizada com licenciandos em ciências biológicas

Este relato de experiência descreve uma aula planejada de acordo com subsídios teóricos do Enfoque Ciência-Tecnologia-Sociedade (CTS), ministrada para uma turma de Licenciatura em Ciências Biológicas dentro das atividades organizadas para a disciplina “Instrumentação para o Ensino de Ciências e Biologia”. A aula teve como objetivo apresentar aos alunos – por meio da temática da automedicação – alguns elementos e princípios relativos ao Movimento CTS, como uma possibilidade para trabalhar conteúdos de Ciências e Biologia na educação básica

Immunologically reactive M. leprae antigens with relevance to diagnosis and vaccine development

<p>Abstract</p> <p>Background</p> <p>Leprosy is a chronic infectious disease caused by <it>Mycobacterium leprae </it>that can manifest a wide variety of immunological and clinical outcomes ranging from potent humoral responses among borderline lepromatous (BL) and lepromatous (LL) patients to strong cellular responses among tuberculoid (TT) and borderline tuberculoid (BT) patients. Until recently, relatively little has been known about the immune responses to individual proteins of <it>M. leprae </it>recognized during leprosy.</p> <p>Methods</p> <p>The immune reactivity to a panel of 33 <it>M. leprae </it>recombinant proteins was evaluated among leprosy patients and controls from a high endemic area for leprosy (Goiania/GO, Central Brazil). Serum IgG responses were measured by ELISA (45 participants/group) and T cell responses (20 participants/group) were evaluated by IFN-gamma production in 24 hours whole blood cultures with antigen (whole blood assay-WBA). Study groups were newly diagnosed, untreated TT/BT and BL/LL leprosy patients classified by Ridley Jopling criteria and household contacts of BL/LL patients (HHC). Control groups were HIV-1 negative pulmonary tuberculosis patients (TB) and healthy individuals from the same endemic area (EC). In silico predictions indicated the level of identity of <it>M. leprae </it>proteins with homologues in other mycobacteria and the presence of T cell and B cell epitopes.</p> <p>Results</p> <p>Despite the prediction that all proteins would be reactive, 16 of 33 (48%) of the single proteins tested were immunogenic (recognized in WBA or ELISA) and seventeen were non-immunogenic (not recognized in either assay). Among the 16 immunogenic proteins, 9 were considered leprosy specific in WBA inducing cell-mediated IFN-gamma secretion from TT/BT patients and HHC. Three of these proteins were also leprosy specific in serology being recognized by serum IgG from LL/BL patients. Seven of the immunogenic proteins were not leprosy specific.</p> <p>Conclusions</p> <p>New <it>M. leprae </it>antigens recognized by antibody responses of BL/LL patients and cellular responses of TT/BT leprosy patients were identified. An improved serological diagnostic test for leprosy could be developed by incorporating these IgG-reactive antigens to the current PGL-I based tests. Moreover our data indicate that the WBA is a robust, relatively simple and user friendly format for a T cell based diagnostic test. The field use of these test formats in leprosy endemic countries could contribute to early leprosy diagnosis before the development of deformities and disabilities.</p

Anti-Inflammatory Activity of the Essential Oil Citral in Experimental Infection with Staphylococcus aureus

This study proposes to implement an alternative and effective strategy for local treatment of disease provoked by S. aureus. For the analysis of possible anti-inflammatory activity of essential oil, after establishing an air pouch model, 48 male mice of Balb/c were treated, infected, and euthanized at 4 and 8 h. Thus, the total and differential white blood cells were counted in the animal’s blood, and cytokines IL-1β, IL-6, and TNF-α were titrated using ELISA in the air pouch lavage. Moreover, TNF-α, IL-1β, and IL-6 gene expression was analyzed through an RT-qPCR array, and S. aureus was quantified using qPCR. Our results, p<0.05, showed that EOC reduced the quantity of microorganisms. The group of mice treated with essential oil citral showed a significant decrease in TNF-α levels in tests demonstrating anti-inflammatory activity. There is no data about the mutual influence of the air pouch model, essential oil citral, and S. aureus. Thus, considering the interaction of these variables and the anti-inflammatory activity of the essential oil citral, we demonstrated, by alternative local treatment, a new antimicrobial agent that is not an antibiotic