Antipathogenic Efficacy of Biogenic Silver Nanoparticles and Antibiofilm Activities Against Multi-drug-Resistant ESKAPE Pathogens.

The silver nanoparticles (AgNPs) were produced by employing a biogenic loom and tested for antipathogenic assets against multi-drug-resistant (MDR) ESKAPE bacteria. Biogenically synthesized AgNPs were characterized adopting various high-throughput techniques such as UHRTEM, SEM with EDX, DLS, TGA-DTA, and XRD and spectroscopic analysis showed polydispersion of nanoparticles. In this context, AgNPs with the attribute of spherical-shaped nanoparticles with an average size of 26 nm were successfully synthesized utilizing bacterial supernatant. The antipathogenic activities of AgNPs were assessed against 11 strains of MDR ESKAPE bacteria including Enterococcus faecium; methicillin-resistant Staphylococcus aureus; Klebsiella pneumonia; Acinetobacter baumannii; Pseudomonas aeruginosa; Enterobacter aerogenes; and Enterobacter species. The exposure of biogenic AgNPs in a well diffusion assay showed all the growth inhibitions of ESKAPE bacteria at 200 µg/ml after 18 h of incubation. Growth kinetics demonstrated maximum killing at 60 µg/ml after 4 h of completion. The highest biofilm depletions were found at 100 µg/ml in adhesion assay. Live/dead assays showed effective killing of the ESKAPE bacteria at 10 µg/ml in pre-existing biofilms. The effective inhibitory concentrations of AgNPs were investigated ranging from 10 to 200 µg/ml. The selected pathogens found sensitive to AgNPs are statistically significant (P < 0.05) than that of cefotaxime/AgNO3. Consequently, a broad spectrum of antimicrobial potentials of AgNPs can be alternative to conventional antimicrobial agents for future medicine.

In Silico and In Vitro Investigation of Phytochemicals Against Shrimp AHPND Syndrome Causing PirA/B Toxins of Vibrio parahaemolyticus.

In Southeast Asia, the penaeid shrimp aquaculture production faces a new pandemic bacterial disease called acute hepatopancreatic necrosis disease (AHPND). The highly profitable pacific white shrimp, Litopenaeus vannamei, has become a challenging species due to severe lethal infections. Recent research has identified a critical pathogen, Vibrio parahaemolyticus, which caused significant loss in the shrimp industry. The disease pathway involves a virulence plasmid encoding binary protein toxins (PirA/B) that cause cell death. The protein toxins were inherited and conjugatively transferred to other Vibrio species through a post-segregational killing system. In this study, "in silico" (Glide, 2021) analysis identified four phytocompounds as myricetin (Myr), ( +)-taxifolin (TF), (-)-epigallocatechin gallate (EGCG), and strychnine (STN) which could be most effective against both the toxins concerning its docking score and affinity. The interactions of complexes and the critical amino acids involved in docking were analyzed using the Discovery Studio (version 2016). Molecular dynamic studies showed lower root mean square deviations (RMSD) and improved stabilization of ( +)-taxifolin (TF) and (-)-epigallocatechin-3-gallate (EGCG) against both the protein toxins. The antibacterial potential of all four selected compounds had tested against pathogenic strains of V. parahaemolyticus through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The best MBC results were observed at concentrations of 1 mg/mL for EGCG and 1.25 mg/mL for TF. Moreover, the complete reduction of viable cell counts in the in vitro bactericidal activity had recorded after 24 h of incubation.

Exploring the Potential of a Herbal Nanoemulsion as an Antimicrobial Mouthwash.

The study aimed to formulate a nanoemulsion, combine it with aqueous extracts of herbal powders, and test its efficiency as caries-preventing mouthwash. Formulation of nanoemulsion using microfluidizer, characterization of nanoemulsion, minimum inhibitory concentration, adherence test, biofilm assay, and artificial mouth assay was carried out. The biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus, and a combination of the three cultures were developed and treated with formulations to study the inhibitory effect of the samples. In artificial mouth assay, human tooth samples were used as surfaces to grow the biofilm of S. mutans, and daily, the teeth were treated with the formulations to test their real-time efficiency. The nanoemulsion was characterized using dynamic light scattering and the size of the particles was within the 100-300 nm range. Above 50 °C, the nanoemulsion combined with plant extract lost its emulsified state within 2 h of incubation, while the nanoemulsion was stable. Nanoemulsion with plant extract inhibited the adherence of L. casei (73%) and biofilm of L. casei (66%). In artificial mouth assay, after 10 days of nanoemulsion, nanoemulsion with plant extract showed DIAGNOdent pen values 3.5 and 2 respectively whereas the negative control value was 14.4 indicating caries initiation. The nanoemulsion with plant extract showed anti-adherence and anti-biofilm activity and hence can be used as a potent anticariogenic mouthwash.

In Silico Protein-Protein Interaction of Pterois volitans Venom with Cancer Inducers of Helicobacter pylori.

Gastric cancer is a pathological condition induced by the bacteria Helicobacter pylori. Targeting the key virulence factors of H. pylori causing gastric cancer is a promising method for treating gastric cancer. Recently, research has been focused on analyzing the adrenergic, cholinergic, and anti-cancer properties of their venom proteins. Testing the anti-cancer activity of the lethal proteins in the venom of P. volitans provides a bioactive compound for cancer treatment. Still, it is also helpful to eliminate the ecological imbalance caused by these fish in the marine environment. This study focuses on an in silico approach using Z-dock to analyze the bioactive prospective of the venom proteins of P. volitans against the essential virulence proteins of H. pylori responsible for inducing cancer. Our in silico docking study using a computational model of the venom proteins and H. pylori proteins has displayed the possible interactions between these proteins. The results revealed that P. volitans hyaluronidase and PV toxin's venom proteins effectively interact with H. pylori proteins Cag A, Cag L, GGT, Cag D, and urease that may be promising proteins in cancer therapy.

Statistical optimization for the efficacious degradation of reactive azo dyes using Acinetobacter baumannii JC359.

The aim of this study is to biodegrade the reactive azo dyes- Reactive black 5 (B-GDN), Reactive red 120 (RP) and Reactive blue 19 (RNB) using bacteria Acinetobacter baumannii JC359. Optimization of the process variables such as pH, temperature, dye concentration, incubation time, inoculum volume and dynamic incubating conditions for dye decolorization were performed using One Factor At a Time (OFAT) approach. Box- Behnken Design (BBD) of Response Surface Methodology (RSM) was further used to optimize the process variables. Decolorization rates of 98.8% for B-GDN, 96% for RP and 96.2% for RNB were observed after treating with A. baumannii for 48 h using the obtained design value. UV-Visible spectrophotometry and FT-IR spectral scan of dye and degraded metabolites confirmed that biodegradation had taken place. Further, the phytotoxicity evaluation was performed with Vigna radiata seeds and the degraded metabolites proved to be non-toxic. Docking studies were performed and it was found that there was significant binding affinity between the dyes and azoreductase enzyme of A. baumannii. Thus, the biodegradation of these reactive azo dyes was found to be a suitable alternative for the effective treatment of textile dyes.