ABSTRACT
The glucocorticoid resistance hereditary condition may emerge from the occurrence of point mutations in the glucocorticoid receptor (GR), which could impair its functionality. Because the main feature of such pathology is the resistance of the hypothalamic-pituitary-adrenal axis to the hormone cortisol, we used the GR ligand binding domain three-dimensional structure to perform computational analysis for eight variants known to cause this clinical condition (I559â¯N, V571A, D641V, G679S, F737L, I747â¯M, L753F and L773P), aiming to understand, on the atom scale, how they cause glucocorticoid resistance. We observed that the mutations generated a reduced affinity to cortisol and they alter some loop conformations, which could be a consequence from changes in protein motion, which in turn could result from the reduced stability of mutant GR structures. Therefore, the analyzed mutations compromise the GR ligand binding domain structure and cortisol binding, which could characterize the glucocorticoid resistance phenotype.
Subject(s)
Glucocorticoids/chemistry , Models, Molecular , Mutation, Missense , Protein Interaction Domains and Motifs , Receptors, Glucocorticoid/chemistry , Receptors, Glucocorticoid/genetics , Amino Acid Sequence , Binding Sites , Evolution, Molecular , Glucocorticoids/pharmacology , Humans , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , Polymorphism, Single Nucleotide , Protein Binding , Protein Interaction Domains and Motifs/genetics , Structure-Activity RelationshipABSTRACT
Foram avaliados alguns parâmetros inerentes ao ELISA, por meio de ensaios de reatividade de soros-controle positivos e negativos para a cisticercose bovina com relação a três tipos de antígenos de larva de Taenia solium: total, de escólex e de membrana. As concentrações de antígeno de 0,25; 0,5; 1; 2 e 4µg por orifício, e as diluições de soro de 1:25, 1:50, 1:100 e 1:200, foram os parâmetros que menos influenciaram no desempenho do teste. A substância bloqueadora, o leite desnatado e as diluições de conjugado, 1:1.250, 1:2.500 e 1:5.000, representaram os melhores indicadores de desempenho do teste. Concluiu-se que essa combinação de critérios deve ser considerada no diagnóstico da cisticercose bovina, em atividades de rotina ou de padronização do referido teste, considerando os três antígenos de larva de T. solium estudados.
Some parameters of ELISA were evaluated using positive and negative bovine sera for cysticercosis and three types of antigens of Taenia solium larvae: total, scolex and membrane. The antigen concentrations (0.25; 0.5; 1; 2 and 4µg/well) and the serum dilutions (1:25, 1:50, 1:100 and 1:200) were the parameters that influenced less the test performance; while blocking substance, skimmed milk, and conjugate dilutions, 1:1.250, 1:2.500 and 1:5.000 were the best indexes of the test performance. It was concluded that this combination of criteria should be considered in the diagnosis of bovine cysticercosis, in routine diagnosis and for the ELISA test standardization.
Subject(s)
Animals , Cysticercosis/diagnosis , Cysticercosis/epidemiology , Cysticercosis/prevention & control , Cysticercus/isolation & purification , Enzyme-Linked Immunosorbent Assay , Taenia solium/isolation & purification , Serologic Tests/methodsABSTRACT
The ELISA test was evaluated for the diagnosis of bovine cysticercosis using heterologous antigens from the larvae of T. solium and T. crassiceps, by using different types of positive and negative control sera, to allow a broader analysis of the results. The ELISA test showed low sensitivity under natural conditions of bovine cysticercosis manifestation, but high rates (up to 90%) under experimental conditions. The high specificity of the test (81-100%) made evident its capacity to differentiate cysticercosis from other bovine diseases. No difference in performance was found among the antigens studied. It was concluded that the ELISA test has deficiencies in detecting anti-cysticercosis antibodies of animals at slaughterhouse. However, it can be useful in detecting experimentally infected animals and differentiating cysticercosis from other bovine diseases.
