Antioxidant Activity of Bioactive Peptide Fractions from Germinated Soybeans Conjugated to Fe3O4 Nanoparticles by the Ugi Multicomponent Reaction.

The conjugation of biomolecules to magnetic nanoparticles has emerged as promising approach in biomedicine as the treatment of several diseases, such as cancer. In this study, conjugation of bioactive peptide fractions from germinated soybeans to magnetite nanoparticles was achieved. Different fractions of germinated soybean peptides (>10 kDa and 5-10 kDa) were for the first time conjugated to previously coated magnetite nanoparticles (with 3-aminopropyltriethoxysilane (APTES) and sodium citrate) by the Ugi four-component reaction. The crystallinity of the nanoparticles was corroborated by X-ray diffraction, while the particle size was determined by scanning transmission electron microscopy. The analyses were carried out using infrared and ultraviolet-visible spectroscopy, dynamic light scattering, and thermogravimetry, which confirmed the coating and functionalization of the magnetite nanoparticles and conjugation of different peptide fractions on their surfaces. The antioxidant activity of the conjugates was determined by the reducing power and hydroxyl radical scavenging activity. The nanoparticles synthesized represent promising materials, as they have found applications in bionanotechnology for enhanced treatment of diseases, such as cancer, due to a higher antioxidant capacity than that of fractions without conjugation. The highest antioxidant capacity was observed for a >10 kDa peptide fraction conjugated to the magnetite nanoparticles coated with APTES.

Deciphering the emergence, genetic diversity and evolution of classical swine fever virus.

Classical swine fever (CSF) is one of the most important infectious diseases causing significant economic losses. Its causal agent, CSF virus (CSFV), is a member of the Pestivirus genus included into the Flaviviridae family. Previous molecular epidemiology studies have revealed the CSFV diversity is divided into three main genotypes and different subgenotypes. However, the classification system for CSFV has not yet been harmonized internationally. Similarly, the phylogeny and evolutionary dynamics of CSFV remain unclear. The current study provides novel and significant insights into the origin, diversification and evolutionary process of CSFV. In addition, the best phylogenetic marker for CSFV capable of reproducing the same phylogenetic and evolutionary information as the complete viral genome is characterized. Also, a reliable cut-off to accurately classify CSFV at genotype and subgenotype levels is established. Based on the time for the most recent common ancestor (tMRCA) reconstruction and cophylogenetic analysis, it was determined that CSFV emerged around 225 years ago when the Tunisian Sheep Virus jumped from its natural host to swine. CSFV emergence was followed by a genetic expansion in three main lineages, driven by the action of positive selection pressure and functional divergence, as main natural forces.

Insights into the Interactions of Fasciola hepatica Cathepsin L3 with a Substrate and Potential Novel Inhibitors through In Silico Approaches.

BACKGROUND: Fasciola hepatica is the causative agent of fascioliasis, a disease affecting grazing animals, causing economic losses in global agriculture and currently being an important human zoonosis. Overuse of chemotherapeutics against fascioliasis has increased the populations of drug resistant parasites. F. hepatica cathepsin L3 is a protease that plays important roles during the life cycle of fluke. Due to its particular collagenolytic activity it is considered an attractive target against the infective phase of F. hepatica. METHODOLOGY/PRINCIPAL FINDINGS: Starting with a three dimensional model of FhCL3 we performed a structure-based design of novel inhibitors through a computational study that combined virtual screening, molecular dynamics simulations, and binding free energy (ΔGbind) calculations. Virtual screening was carried out by docking inhibitors obtained from the MYBRIDGE-HitFinder database inside FhCL3 and human cathepsin L substrate-binding sites. On the basis of dock-scores, five compounds were predicted as selective inhibitors of FhCL3. Molecular dynamic simulations were performed and, subsequently, an end-point method was employed to predict ΔGbind values. Two compounds with the best ΔGbind values (-10.68 kcal/mol and -7.16 kcal/mol), comparable to that of the positive control (-10.55 kcal/mol), were identified. A similar approach was followed to structurally and energetically characterize the interface of FhCL3 in complex with a peptidic substrate. Finally, through pair-wise and per-residue free energy decomposition we identified residues that are critical for the substrate/ligand binding and for the enzyme specificity. CONCLUSIONS/SIGNIFICANCE: The present study is the first computer-aided drug design approach against F. hepatica cathepsins. Here we predict the principal determinants of binding of FhCL3 in complex with a natural substrate by detailed energetic characterization of protease interaction surface. We also propose novel compounds as FhCL3 inhibitors. Overall, these results will foster the future rational design of new inhibitors against FhCL3, as well as other F. hepatica cathepsins.