Comparative Computational Analysis of Dirithromycin and Azithromycin in Search for a Potent Drug against COVID-19 caused by SARS-CoV-2: Evidence from molecular docking and dynamic simulation.

Due to the emergency and uncontrolled situation caused by the COVID-19 pandemic that arising in the entire world, it is necessary to choose available drugs that can inhibit or prevent the disease. Therefore, the repurposing of the commercial antibiotic, dirithromycin has been screened for the first time against fifteen receptors and compared to the azithromycin using a molecular docking approach to identify possible SARS-CoV-2 inhibitors. Our docking results showed that dirithromycin fit significantly in the Furin catalytic pocket having the lowest binding score (-9.9 Kcal/mol) with respect to azithromycin (-9.4 Kcal/mol) and can interact and block both Asp154 and Ser368 residues by Van der Walls interaction as well as bound to His194 and Ser368 residues via hydrogen bonds. Good results were also obtained with the Tmprss-2 receptor. A Molecular Dynamic simulation was assessed to confirm this interaction. Additionally, detailed receptor-ligand interactions with SARS-CoV-2 and pro-inflammatory mediators were investigated suggesting more target information with interesting results. The findings of this study are very efficient and provide a basis for the development of dirithromycin for clinical trial applications to be efficient in treating SARS-CoV-2 infections.

Enzymatic activities in different strains isolated from healthy and brittle leaf disease affected date palm leaves: study of amylase production conditions.

The present study aimed to investigate and compare the enzymatic production of endophytic bacteria isolated from healthy and brittle leaf disease affected date palm leaves (pectinase, cellulase, lipase, and amylase). The findings revealed that the enzymatic products from the bacterial isolates of healthy date palm leaves were primarily 33% amylolytic enzyme, 33 % cellulase, 25 % pectinase, and 25 % lipase. The isolates from brittle leaf disease date palm leaves, on the other hand, were noted to produce 16 % amylolytic enzyme, 20 % cellulose, 50 % pectinase, and 50 % lipase. The effects of temperature and pH on amylase, pectinase, and cellulose activities were investigated. The Bacillus subtilis JN934392 strain isolated from healthy date palm leaves produced higher levels of amylase activity at pH 7. A Box Behnken Design (BBD) was employed to optimize amylase extraction. Maximal activity was observed at pH and temperature ranges of pH 6-6.5 and 37-39 °C, respectively. Under those conditions, amylase activity was noted to be attained 9.37 U/ml. The results showed that the enzyme was able to maintain more than 50 % of its activity over a temperature range of 50-80 °C, with an optimum at 70 °C. This bacterial amylase showed high activity compared to other bacteria, which provides support for its promising candidacy for future industrial application.