Protective activity of beta-1, 3-glucan binding protein against AAPH induced oxidative stress in Saccharomyces cerevisiae.

The present work aimed to evaluate the antioxidant efficacy of beta-1,3-glucan binding/recognition protein against oxidative stress-induced Saccharomyces cerevisiae. Beta-1,3-glucan binding/recognition protein was attained from the Paratelphusa hydrodromus (Phß-GBP) using laminarin coupled Sepharose CL-6B column. The structural characteristics of Phß-GBP were analyzed through circular dichroism (CD), fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (1H NMR) analysis. CD spectrum showed the occurrence of α-helix (4.5%), ß-sheets (23.6%), ß-turn (17.2%) and random coils (54.8%). FTIR confirms the occurrence of amide and aromatic compounds whereas 1H NMR predicts the secondary structures and presence of amino acids in the Phß-GBP. In vitro radical scavenging analysis disclose that Phß-GBP has the potential to scavenge DPPH (73%), peroxyl radicals (81%) and hydrogen peroxide (56%) at 100µg/ml concentration. Reactive oxygen species production, lipid peroxidation, cell death, and DNA damage were decreased in the Phß-GBP pretreated S. cerevisiae. In silico protein-protein interaction was performed between the ß-GBP-glutathione reductase and ß-GBP-catalase A. The interaction study reveals that glutathione reductase and catalase A interacts with ß-GBP to reduce the oxidized glutathione and remove free radicals. This finding demonstrates that Phß-GBP may act as a good antioxidant which protects from human pathologies linked with oxidative stress.

Enhanced antibacterial activity of hemocyanin purified from Portunus pelagicus hemolymph combined with silver nanoparticles - Intracellular uptake and mode of action.

Recently, biogenic nanoparticles have been considered promising candidates for manufacturing antibacterial nanodrugs. Here, we synthesized AgNPs using the crab-borne antibacterial agent hemocyanin and assessed the antibacterial action against several pathogenic bacteria. In this study, the crustacean immune protein hemocyanin (Pp-Hc, 78 kDa) purified from Portunus pelagicus hemolymph was used to fabricate silver nanoparticles. Characterization of hemocyanin-fabricated AgNPs (Pp-Hc AgNPs) were achieved using ultraviolet-visible spectrophotometer, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), high-resolution-transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy. The antibacterial efficacy of AgNO3,Pp-Hc and Pp-Hc AgNPs was compared by growth inhibition, antibiofilm and live and dead analyses. Based on the results, Pp-Hc AgNPs was more efficient than Pp-Hc and AgNO3 against pathogenic bacteria. Mechanistic analysis revealed membrane damage and reactive oxygen species (ROS) generation, suggesting that Pp-Hc and Pp-Hc AgNPs rely to similar modes of action. Intracellular protein molecules and nucleic acid leakage confirmed that Pp-Hc AgNPs increase membrane permeability, leading to cell death. Based on our results, capping of the exterior surface of nanoparticles with antimicrobial crab-borne peptides, such as Pp-Hc, improves their functions as potential agents against bacterial diseases, which may be useful in clinical applications.

Microbial exopolymer-capped selenium nanowires - Towards new antibacterial, antibiofilm and arbovirus vector larvicides?

Arboviral diseases and microbial pathogens resistant to commercially available drugs are on the rise. Herein, a facile microbial-based approach was developed to synthesize selenium nanowires (Se NWs) using microbial exopolymer (MEP) extracted from the Bacillus licheniformis (probiotic bacteria). MEP-Se NWs were characterized using UV-Visible, XRD, FTIR, HR-TEM, FE-SEM and EDX. An UV-Visible peak was detected at 330 nm while XRD spectrum data pointed out the crystalline nature of MEP-Se NWs. FTIR spectrum revealed functional groups with strong absorption peaks in the range 3898.52-477.97 cm-1. FE-SEM and HR-TEM revealed that the obtained structures were nanowires of 10-30 nm diameter. Se presence was confirmed by EDX analysis. MEP-Se NWs at 100 µg/ml highly suppressed the growth of both Gram (-) and Gram (+) bacteria. Further, microscopic analysis evidenced that 75 µg/ml MEP-Se NWs suppressed biofilm formation. Hemolytic assays showed that MEP-Se NWs were moderately cytotoxic. In addition, LC50 values lower than 10 µg/ml were estimated testing MEP-Se NWs on both Aedes aegypti and Culex quinquefasciatus 3rd instar larvae. Morphological and histological techniques were used to elucidate on the damages triggered in mosquito tissues, with special reference to midgut, post-exposure to MEP-Se NWs. Therefore, based on our findings, MEP-Se NWs can be considered for entomological and biomedical applications, with special reference to the management of biofilm forming microbial pathogens and arbovirus mosquito vectors.