Isolation, characterization, and multimodal evaluation of novel glycolipid biosurfactant derived from Bacillus species: A promising Staphylococcus aureus tyrosyl-tRNA synthetase inhibitor through molecular docking and MD simulations.

Glycolipid-based biosurfactants (BSs), known for their intriguing and diverse properties, represent a largely uncharted territory in the realm of potential biomedical applications. This field holds great promise yet remains largely unexplored. This investigation provides new insights into the isolation, characterization, and comprehensive biomedical assessment of a novel glycolipid biosurfactant derived from Bacillus species, meeting the growing demand for understanding its multifaceted impact on various biomedical issues. Within this framework, two glycolipids, BG2A and BG2B, emerged as the most proficient strains in biosurfactant (BS) production. The biosurfactants (BSs) ascertained as glycolipids via thin layer chromatography (TLC) exhibited antimicrobial activity against S. aureus and E. coli. Both isolates exhibited anticancer effects against cervical carcinoma cells and demonstrated significant anti-biofilm activity against V. cholerae. Moreover, molecular docking and molecular dynamics (MD) simulations were employed to explore their antimicrobial resistance properties against Tyrosyl-tRNA synthetase (TyrRS) of Staphylococcus aureus, a well-annotated molecular target. Characterization and interpretation using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H and 13C NMR) confirmed that the BSs produced by each strain were glycolipids. These findings suggest that the isolated BSs can serve as effective agents with antibiofilm, antimicrobial, antioxidant, and anticancer properties, in addition to their considerable antibacterial resistance attributes.

Photocatalytic activity of biosynthesized silver nanoparticle fosters oxidative stress at nanoparticle interface resulting in antimicrobial and cytotoxic activities.

Inside the biological milieu, nanoparticles with photocatalytic activity have potential to trigger cell death non-specifically due to production of reactive oxygen species (ROS) upon reacting with biological entities. Silver nanoparticle (AgNP) possessing narrow band gap energy can exhibit high light absorption property and significant photocatalytic activity. This study intends to explore the effects of ROS generated due to photocatalytic activity of AgNP on antimicrobial and cytotoxic propensities. To this end, AgNP was synthesized using the principle of green chemistry from the peel extract of Punica granatum L., and was characterized using UV-Vis spectroscope, transmission electron microscope and x-ray diffraction, and so forth. The antimicrobial activity of AgNP against studied bacteria indicated that, ROS generated at AgNP interface develop stress on bacterial membrane leading to bacterial cell death, whereas Alamar Blue dye reduction assay indicated that increased cytotoxic activity with increasing concentrations of AgNP. The γH2AX activity assay revealed that increasing the concentrations of AgNP increased DNA damaging activity. The results altogether demonstrated that both antimicrobial and cytotoxic propensities are triggered primarily due interfacial ROS generation by photocatalytic AgNP, which caused membrane deformation in bacteria and DNA damage in HT1080 cells resulting in cell death.

Cytotoxic effect of microbial biosurfactants against human embryonic kidney cancerous cell: HEK-293 and their possible role in apoptosis.

Two different microbial biosurfactants S9BS and CHBS were isolated from Lysinibacillus fusiformis S9 and Bacillus tequilensis CH. Cytotoxicity effect of these biosurfactants on human embryonic kidney cancerous cell (HEK-293) were studied with the help of 3-(4,5-dimethylthiazol-2yl-)-2, 5-diphenyl tetrazolium bromide (MTT) assay and morphological changes were observed under inverted microscope. The biosurfactants exhibited positive cytotoxic effect on HEK-293 cell line. It was found that LC50 of S9BS and CHBS were 75 and 100 µg ml(-1), respectively. Further cell cycle and apoptosis analysis of biosurfactant-treated HEK-293 cell line were done by FACS. In this study, cytotoxic effect of glycolipid biosurfactant against HEK-293 cell lines is reported for the first time. Mechanism towards increased membrane permeability of biosurfactant-treated cancer cell may be the incorporation of its lipid moiety into the plasma membrane leading to formation of pores and membrane disruption. Hence, these microbial biosurfactants can prove to be significant biomolecule for cancer treatment.