Coronavirus Acute Respiratory Syndrome (SARS-CoV-2) is a very recent viral infection and has generated one of the world’s biggest problems of all time. There is no scientific evidence and clinical trials to indicate that possible therapies have shown results in suspected or confirmed patients other than the use of immunizations. Given the above, some substances are being studied to be applied to contain their spread and further damage. This work aims to perform an in silico study of amoxicillin, widely known as an antibiotic and used to prevent bacterial infections and a possible biomarker made from a complex with Europium (Eu). It was shown to have the ability to interact with the COVID-19 protein in Mpro protease as ligands. The study was conducted using the AutoDock Vina with Lamarckian genetic model algorithm (GA) combined with the estimation of grid-based energy in rigid and flexible conformation. Compared to affinity energy, amoxicillin presented [Formula: see text][Formula: see text]kcal/mol, which was better than its co-crystallized ligand in the study. The Europium complex, where its synthesis was also demonstrated in this work, presented energy of [Formula: see text][Formula: see text]kcal/mol with hydrogen bonds and possible color change when UV light was applied. For the choice of the best poses in the simulation, the neural network parameter, NNScore2, was used. It can be affirmed that this study is still introductory but promising both in the treatment and identification of the virus.

The emergence of the new coronavirus (SARS-COV-2) is known to trigger some common diseases in humans such as pneumonia and diarrhea, the search for appropriate therapy combat COVID-19 has been intense and exhaustive. Motivation/Background: Thus, based on the rational study of drugs, a survey of potential ligands that can inhibit the vital protein in virus replication, the main protease (Mpro), has been carried out worldwide. Method: In this battle, the antiviral Remdesivir, which was created to fight the Ebola virus, proved, through the molecular anchorage, to be quite effective against its target because it presented affinity energy far superior to its co-crystallized ligand. Results: In this work, a study was carried out with Remdesivir and its derivatives, obtained in a zinc database15, to present a possible alternative, based on its structure-affinity, as potential Inhibitors of SARS-COV-2 MPro, with affinity energy ranging from -6.3 to -8.2 kcal/mol. Conclusions: It was found that both remdesivir and its diastereoisomeric derivatives have an affinity with the main protease (Mpro), responsible for viral replication, with inhibition capacity and possible alternative in its treatment.

The objective of this work was to evaluate the effect of the use of an artificial substrate for periphytic biofilm growth on the microbiological composition of the biofilm, water quality, and zootechnical performance of Nile tilapia (Oreochromis niloticus) in rearing tanks. The experiment consisted of two treatments: presence and absence of artificial substrate for the growth of periphyton, with five replicates. Water quality parameters were evaluated throughout the entire experimental period. Every two weeks, samples of the periphyton were collected for the analysis of its microbiological composition and biometric measurements of the fish were performed. The number of heterotrophic bacteria in the biofilm increased during the experimental period, but that of Aeromonas decreased with the use of the artificial substrate. The total ammonia nitrogen in the tanks with periphyton reduced in 30% compared with that of the control. Tilapia reared with the biofilm showed a final weight 2.4 times greater than that of those subjected to the control, as well as an increase of 59.19% in their productivity. The use of an artificial substrate for periphytic biofilm in Nile tilapia rearing tanks favors the maintenance of the quality of the culture water, the protection of the fish against pathogens, and the improvement of the zootechnical performance of the fish.