In-silico study for the identification of potential destabilizers between the spike protein of SARS-CoV-2 and human ACE-2.

The emergence of the new SARS-CoV-2 virus, which causes the disease known as COVID-19, has generated a pandemic that has plunged the world into a health crisis. The infection process is triggered by the direct binding of the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2 to the angiotensin-converting enzyme 2 (ACE2) of the host cell. In the present study, virtual screening techniques such as molecular docking, molecular dynamics, calculation of free energy using the GBSA method, prediction of drug similarity, pharmacokinetic, and toxicological properties of various ligands interacting with the RBD-ACE2 complex were applied. The ligands radotinib, hinokiflavone, and ginkgetin were identified as potential destabilizers of the RBD-ACE2 interaction, which could produce their pharmacological effect by interacting at an allosteric site of ACE2, with affinity energy values of -10.2 ± 0.1, -9.8 ± 0.0, and -9.4 ± 0.0 kcal/mol, indicating strong receptor affinity. The complex with hinokiflavone showed the highest conformational stability and rigidity of the dynamic simulation and also obtained the best binding free energy of the three molecules, with an energy of -215.86 kcal/mol.

Virtual screening using docking and molecular dynamics of cannabinoid analogs against CB1 and CB2 receptors.

BACKGROUND: Cannabis sativa has been attributed to different pharmacological properties. A number of secondary metabolites such as tetrahydrocannabinol (THC), cannabinol (CBD), and different analogs, with highly promising biological activity on CB1 and CB2 receptors, have been identified. METHODS: Thus, this study aimed was to evaluate the activity of THC, CBD, and their analogs using molecular docking and molecular dynamics simulations (MD) methods. Initially, the molecules (ligands) were selected by bioinformatics searches in databases. Subsequently, CB1 and CB2 receptors were retrieved from the protein data bank database. Afterward, each receptor and its ligands were optimized to perform molecular docking. Then, MD Simulation was performed with the most stable ligand-receptor complexes. Finally, the Molecular Mechanics-Generalized Born Surface Area (MM-PBSA) method was applied to analyze the binding free energy between ligands and cannabinoid receptors. RESULTS: The results obtained showed that ligand LS-61176 presented the best affinity in the molecular docking analysis. Also, this analog could be a CB1 negative allosteric modulator like CBD and probably an agonist in CB2 like THC and CBD according to their dynamic behavior in silico. The possibility of having a THC and a CBD analog (LS-61176) as a promising molecule for experimental evaluation since it could have no central side-effects on CB1 and have effects of CB2 useful in pain, inflammation, and some immunological disorders. Docking results were validate using ROC curve for both cannabinoids receptor where AUC for CB1 receptor was 0.894±0.024, and for CB2 receptor AUC was 0.832±0032, indicating good affinity prediction.

Intestinal coccidian: an overview epidemiologic worldwide and Colombia / Coccidias Intestinales: Panorama epidemiológico mundial y en Colombia

Intestinal coccidia have been classified as protozoa of the Apicomplex phylum, with the presence of an intracellular behavior and adaptation to the habit of the intestinal mucosa, related to several parasites that can cause enteric infections in humans, generating especially complications in immunocompetent patients and opportunistic infections in immunosuppressed patients. Alterations such as HIV/AIDS, cancer and immunosuppression. Cryptosporidium spp., Cyclospora cayetanensis and Cystoisospora belli are frequently found in the species. Multiple cases have been reported in which their parasitic organisms are associated with varying degrees of infections in the host, generally characterized by gastrointestinal clinical manifestations that can be observed with diarrhea, vomiting, abdominal cramps, malaise and severe dehydration. Therefore, in this review a specific study of epidemiology has been conducted in relation to its distribution throughout the world and in Colombia, especially, global and national reports about the association of coccidia informed with HIV/AIDS. Proposed revision considering the needs of a consolidated study in parasitology, establishing clarifications from the transmission mechanisms, global and national epidemiological situation, impact at a clinical level related to immunocompetent and immunocompromised individuals, as well as a focus on public health in institutional government policies and scientific information based on the characterization of coccidia in the tropical region and Colombia.

Los coccidios intestinales se han clasificado como protozoos del Apicomplexa phylum, con presencia de un comportamiento intracelular y adaptación al hábito de la mucosa intestinal, relacionado con varios parásitos que pueden causar infecciones entéricas en los humanos, generando especialmente complicaciones en pacientes inmunocompetentes e infecciones oportunistas en pacientes inmunodeprimidos. Alteraciones como el VIH/SIDA, cáncer e inmunosupresión con tratamientos farmacológicos. En las especies que se encuentran frecuentemente se encuentran Cryptosporidium spp., Cyclospora cayetanensis y Cystoisospora belli. Se han reportado múltiples casos en los que sus organismos parásitos se asocian a diversos grados de infecciones en el huésped, generalmente caracterizadas por manifestaciones clínicas gastrointestinales que pueden observarse con diarrea, vómitos, calambres abdominales, malestar general y deshidratación severa. Por lo tanto, en esta revisión se ha realizado un estudio específico de epidemiología con relación a su distribución en todo el mundo y en Colombia, especialmente, reportes a nivel global y nacional a cerca de la asociación de coccidios informados con el VIH/SIDA. Revisión propuesta con el objetivo de considerar las necesidades de un estudio consolidado a nivel del campo de la parasitología, evidenciando literatura actualizada, estableciendo información de los mecanismos de transmisión, situación epidemiológica global y nacional, impacto a nivel clínico relacionadas con individuos inmunocompetentes e inmunocomprometidos, así como un enfoque en salud pública en políticas gubernamentales institucionales y la información científica basada en la caracterización de coccidias en la región tropical y principalmente en Colombia.

Sickle Cell Trait Induces Oxidative Damage on Plasmodium falciparum Proteome at Erythrocyte Stages.

The presence of hemoglobin A-S (HbAS) in erythrocytes has been related to the high production of reactive oxygen species (ROS) and an increased in intracellular oxidative stress that affects the progress of Plasmodium erythrocytic cycle life and attenuates its serious clinical symptoms. Nevertheless, oxidative effects on P. falciparum proteome across the intraerythrocytic cycle in the presence of HbAS traits have not been described yet. Here, an immune dot-blot assay was used to quantify the carbonyl index (C.I) on P. falciparum 3D7 proteome at the different asexual erythrocytic stages. Protein carbonylation on parasites cultivated in erythrocytes from two donors with HbAS increased 5.34 ± 1.42 folds at the ring stage compared to control grown in hemoglobin A-A (HbAA) red blood cells. Whereas at trophozoites and schizonts stages were augmented 2.80 ± 0.52 and 3.05 ± 0.75 folds, respectively. Besides proteins involved in processes of the stress response, recognition and invasion were identified from schizonts carbonylated bands by combining SDS-PAGE with MALDI-TOF-TOF analysis. Our results reinforce the hypothesis that such oxidative modifications do not appear to happen randomly, and the sickle cell trait affects mainly a small fraction of parasite proteins particularly sensitive to ROS.

Protein Carbonylation As a Biomarker of Heavy Metal, Cd and Pb, Damage in Paspalum fasciculatum Willd. ex Flüggé.

Heavy metal tolerant plants have phytoremediation potential for the recovery of contaminated soils, and the characterization of their metabolic adaptation processes is an important starting point to elucidate their tolerance mechanisms at molecular, biochemical and physiological levels. In this research, the effects of Cd and Pb on growth and protein carbonylation in tissues of Paspalum fasciculatum exposed to 30 and 50 mg·Kg-1 Cd and Pb respectively were determined. P. fasciculatum seedlings exposed to metals grew more than controls until 60 days of cultivation and limited their oxidative effects to a reduced protein group. Carbonyl indexes in leaf and root proteins reached a significant increase concerning their controls in plants exposed 30 days to Cd and 60 days to Pb. From the combined approach of Western Blot with Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and protein analysis by Matrix Asisted Laser Desorption/Ionisation - Time Of Flight (MALDI-TOF/TOF) mass spectrometry, chloroplastic proteins were identified into the main oxidative stress-inducible proteins to Cd and Pb, such as subunits α, γ of ATP synthetase, Chlorophyll CP26 binding protein, fructose-bisphosphate aldolase and long-chain ribulose bisphosphate carboxylase (RuBisCO LSU). Cd generated damage in the photosynthetic machinery of the leaves of P. fasciculatum into the first 30 days of treatment; five of the oxidized proteins are involved in photosynthesis processes. Moreover, there was a proteolytic fragmentation of the RuBisCO LSU. Results showed that intrinsic tolerance of P. fasciculatum to these metals reached 60 days in our conditions, along with the bioaccumulating appreciable quantities of metals in their roots.

Membrane protein carbonylation of Plasmodium falciparum infected erythrocytes under conditions of sickle cell trait and G6PD deficiency.

Deficiency of glucose-6-phosphate dehydrogenase (G6PD) and sickle cell trait (SCT) are described as the polymorphic disorders prevalent in erythrocytes. Both are considered the result of the selective pressure exerted by Plasmodium parasites over human genome, due to a certain degree of resistance to the clinical symptoms of severe malaria. There exist in both a prooxidant environment that favors the oxidative damage on membrane proteins, which probably is part of molecular protector mechanisms. Nevertheless, mechanisms are not completely understood at molecular level for each polymorphism yet, and even less if are commons for several of them. Here, synchronous cultures at high parasitemia levels of P. falciparum 3D7 were used to quantify oxidative damage in membrane proteins of erythrocytes with G6PD deficient and SCT. Carbonyl index by dot blot assay was used to calculate the variation of oxidative damage during the asexual phases. Besides, protein carbonylation profiles were obtained by Western blot and complemented with mass spectrometry using MALDI-TOF-TOF analysis. Erythrocytes with G6PD deficient and SCT showed higher carbonyl index values than control and similar profiles of carbonylated proteins; moreover, cytoskeletal and stress response proteins were identified as the main targets of oxidative damage. Therefore, both polymorphisms promote carbonylation on the same membrane proteins. Finally, these results allowed to reinforce the hypothesis of oxidative damage in erythrocyte membrane proteins as molecular mechanism of human adaptation to malaria infection.