Antagonistic and enzymatic activities of Bacillus species isolated from the fish gastrointestinal tract as potential probiotics use in Artemia culture.

Probiotics have been used successfully in aquaculture to enhance disease resistance, nutrition, and/or growth of cultured organisms. Six strains of Bacillus were isolated from the intestinal tracts of fish and recognised by conventional biochemical traits. The six isolated strains were Bacillus cereus and Bacillus subtilis using MALDI-TOF-MS technique. The probiotic properties of these Bacillus strains were studied. The tested bacillus strains exhibit antibacterial activity against the different pathogens. The strain S5 gave the important inhibition zones against most pathogens (20.5, 20.33, 23, and 21 mm against Vibrio alginolyticus, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella typhimurium, respectively). According to our results, all Bacillus strains have extracellular components that can stop pathogenic bacteria from growing. The enzymatic characterization showed that the tested strains can produce several biotechnological enzymes such as α-glucosidase, naphtol-AS-BI-Phosphohydrolase, esterase lipase, acid phosphatase, alkaline phosphatase, amylase, lipase, caseinase, and lecithinase. All Bacillus strains were adhesive to polystyrene. The adding Bacillus strains to the Artemia culture exerted significantly greater effects on the survival of Artemia. The challenge test on Artemia culture showed that the protection against pathogenic Vibrio was improved. These findings allow us to recommend the examined strains as prospective probiotic options for the Artemia culture, which will be used as food additives to improve the culture conditions of crustacean larvae and marine fish.

Improving the anti-diabetic and anti-hyperlipidemic activities of extra virgin olive oil by the incorporation of diallyl sulfide.

Development of novel functional foods is trending as one of the hot topics in food science and food/beverage industries. In the present study, the anti-diabetic, anti-hyperlipidemic and histo-protective effects of the extra virgin olive oil (EVOO) enriched with the organosulfur diallyl sulfide (DAS) (DAS-rich EVOO) were evaluated in alloxan-induced diabetic mice. The ingestion of EVOO (500µL daily for two weeks) attenuated alloxan-induced elevated glucose, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase, lactate dehydrogenase (LDH), urea and creatinine. It also normalized the levels of triglycerides (TG), total cholesterols (TC), low-density lipoprotein-cholesterol (LDL-c) and their consequent atherogenic index of plasma (AIP) in diabetic animals. Additionally, EVOO prevented lipid peroxidation (MDA) and reduced the level of hydrogen peroxide (H2O2) in diabetic animals. Concomitantly, it enhanced the activity of the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD), reducing thereby tissue oxidative stress injury. The overall histologic (pancreas, liver, and kidney) alterations were also improved after EVOO ingestion. The manifest anti-diabetic, lipid-lowering and histo-protective properties of EVOO were markedly potentiated with DAS-rich EVOO suggesting possible synergistic interactions between DAS and EVOO lipophilic bioactive ingredients. Overall, EVOO and DAS-rich EVOO show promise as functional foods and/or adjuvants for the treatment of diabetes and its complications.

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.

Phytochemical Analysis, Antioxidant, Antimicrobial, and Anti-Swarming Properties of Hibiscus sabdariffa L. Calyx Extracts: In Vitro and In Silico Modelling Approaches.

The aim of this study was to investigate the phytochemical composition of dried Roselle calyx (Hibiscus sabdariffa L.) using both ethanolic and aqueous extracts. We report the antimicrobial activities against a wide range of bacteria, yeast, and fungi. The antioxidant activities were tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and 2-2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging assays. We report also for the first time the effect of the swarming motility in Pseudomonas aeruginosa PAO1. Our results showed that the tested two extracts were a rich source of phenols, flavonoids, and tannins with different degrees. Additionally, eleven phytoconstituents were identified by LC/MS technique (Hibiscus acid: 3-caffeoylquinic acid, 5-caffeoylquinic acid, 5-feruloylquinic acid, cyanidin 3-o-glucoside, myricetin, quercetin 7-o-rutinoside, quercetin 3-o-glucoside, delphinidin 3-o-sambubioside, and kaempferol 3-o-p-coumaroyl-glucoside). Also, it was shown that the calyx extract can scavenge 86% of the DPPH radical, while the rate of 53% and 23% of inhibition of the DPPH was obtained only at the concentration of 125 and 50 µg/mL, and a small inhibition was made at a concentration of 5 µg/mL. Roselle extracts inhibited the growth of the selected microorganisms at low concentrations, while higher concentrations are needed to completely kill them. However, no activity against CVB-3 was recorded for both extracts. In addition, the obtained extracts reduced the swarming motility of P. aeruginosa at 2.5 mg/ml. The docking simulation showed acceptable binding affinities (up to -9.6 kcal/mol) and interaction with key residues of 1JIJ, 2QZW, and 2UVO. The obtained results highlighted the potential use of Roselle extract as a source of phytoconstituents with promising antimicrobial, antioxidant, and anti-quorum sensing activities.

Effect of Adiantum philippense Extract on Biofilm Formation, Adhesion With Its Antibacterial Activities Against Foodborne Pathogens, and Characterization of Bioactive Metabolites: An in vitro-in silico Approach.

Adiantum philippense (A. philippense), an ethnomedicinally important fern, has become an interesting herb in the search for novel bioactive metabolites, which can also be used as therapeutic agents. Primarily, in this study, A. philippense crude extract was screened for its phytochemical constituents, antagonistic potential, and effect on bacterial adhesion and biofilm formation against common food pathogens. Phytochemical profiling of A. philippense was carried out by using High Resolution-Liquid Chromatography and Mass Spectroscopy (HR-LCMS) followed by antibacterial activity via agar cup/well diffusion, broth microdilution susceptibility methods, and growth curve analysis. Antibiofilm potency and efficacy were assessed on the development, formation, and texture of biofilms through light microscopy, fluorescent microscopy, scanning electron microscopy, and the assessment of exopolysaccharide production. Correspondingly, a checkerboard test was performed to evaluate the combinatorial effect of A. philippense and chloramphenicol. Lastly, molecular docking studies of identified phytochemicals with adhesin proteins of tested food pathogens, which helps the bacteria in surface attachment and leads to biofilm formation, were assessed. A. philippense crude extract was found to be active against all tested food pathogens, displaying the rapid time-dependent kinetics of bacterial killing. A. philippense crude extract also impedes the biofilm matrix by reducing the total content of exopolysaccharide, and, likewise, the microscopic images revealed a great extent of disruption in the architecture of biofilms. A synergy was observed between A. philippense crude extract and chloramphenicol for E. coli, S. aureus, and P. aeruginosa, whereas an additive effect was observed for S. flexneri. Various bioactive phytochemicals were categorized from A. philippense crude extract using HR-LCMS. The molecular docking of these identified phytochemicals was interrelated with the active site residues of adhesin proteins, IcsA, Sortase A, OprD, EspA, and FimH from S. flexneri, S. aureus, P. aeruginosa, and E. coli, respectively. Thus, our findings represent the bioactivity and potency of A. philippense crude extract against food pathogens not only in their planktonic forms but also against/in biofilms for the first time. We have also correlated these findings with the possible mechanism of biofilm inhibition via targeting adhesin proteins, which could be explored further to design new bioactive compounds against biofilm producing foodborne bacterial pathogens.

Extracellular enzymes and adhesive properties of medically important Candida spp. strains from landfill leachate.

The virulence properties of Candida spp. presents in landfill leachate still unknown until today and they constitutes a serious source of potential danger for humans. We investigate the antifungal susceptibility, production of hydrolytic enzymes and biofilm formation on polystyrene as well as glass in Candida spp. strains isolated from a landfill leachate treatment station in Borj Chakir (Tunisia). 37 yeast strains were isolated belonging to the following species: C. robusta, C. lusitaniae, C. tropicalis, C. krusei. Most isolated yeast strains were resistant to Amphotericin B, produced several hydrolytic enzymes (67.56% produced phospholipase, 86.04% protease, 64.86% esterase) and most of them are able to degrade hemoglobin. All assayed Candida strains have been able to form biofilm on polystyrene depending on the species and strain of Candida. Landfills receiving clinical waste are a potential source of Candida ssp. strains with several virulence properties which allow them to survive in different aquatic biotopes.