Gracilaria salicornia as potential substratum for green synthesis of Cerium Oxide Nanoparticles coupled hydrogel: An effective antimicrobial thin film.

Sodium alginate based (SA) hydrogel supplemented Cerium Oxide nanoparticles (CeO2NPs) was produced to fabricate an antimicrobial thin film using an aqueous extract of G. salicornia (Gs). The Gs-CeO2NPs were characterized via SEM, FT-IR, EDX, XRD and DLS, the particle size was 200 nm, agreed with XRD. Gs-SA powder was extracted and incorporated with CeO2NPs. The Gs-SA and its composite thin film (Gs-CeO2NPs-SATF) were characterized including viscosity, FT-IR, TGA, and SEM. The adhesion of Gs-SA coating around Gs-CeO2NPs confirmed via FTIR. The antimicrobial properties of Gs-CeO2NPs and CeO2NPs-SATF were proved in MICs for E. coli and Candida albicans at 62.5 and 250.0 µg/mL. The biofilm inhibition efficiency of CeO2NPs-SATF was 74.67 ± 0.98% and 65.45 ± 0.40% for E. coli and Candida albicans. The CeO2NPs-SATF was polydisperse in nature and film structure gets fluctuated with NPs concentration. Increased NPs into SATF enhances pore size of gel and corroborated with viscous behaviour. The cytotoxicity of Gs-CeO2NP-SA in Artemia salina at higher concentration 100 µg/mL provides less lethal effect into the adult. The antioxidant activity of Gs-CeO2NP-SA in DPPH assay was noticed at 0.6 mg ml-1 with radical scavenging activity at 65.85 ± 0.81%. Thus the Gs-CeO2NP-SATF would be suitable in antimicrobial applications.

Hydrothermal synthesis of spindle structure copper ferrite-graphene oxide nanocomposites for enhanced photocatalytic dye degradation and in-vitro antibacterial activity.

In this study, a one-step hydrothermal approach was used to make pure magnetic copper ferrite (CuFe2O4) and copper ferrite-graphene oxide (CuFe2O4-rGO) nanocomposites (NCs) and spinel structure CuFe2O4 with a single phase of tetragonal CuFe2O4-rGO-NCs was confirmed by the XRD. Then, characterization of CuFe2O4-rGO-NCs was done using ng Raman spectroscopy, FT-IR, TGA-DTA, EDS, SEM, and TEM. The synthesized NCs was exposed to UV light to evaluate its photocatalytic activity for the degradation of methylene blue (MB) and rhodamine B (RhB) with CuFe2O4 and CuFe2O4-rGO-NCs, respectively. The catalyst CuFe2O4-rGO-NCs provided higher degradation of MB (94%) than for RhB (86%) under UV light irradiation compared to CuFe2O4. Further, the antibacterial activities of CuFe2O4-NPs and CuFe2O4-rGO-NCs were tested against Gram-negative and -positive bacterial pathogens such as Vibrio cholera (V. cholera); Escherichia coli (E. coli); Pseudomonas aeruginosa (P. aeruginosa); Bacillus subtilis (B. subtilis); Staphylococcus aureus (S. aureus); and Staphylococcus epidermidis (S. epidermidis) by well diffusion method. At 100 µg/mL concentrations of CuFe2O4-rGO-NCs, maximal growth inhibition was shown against E. coli (18 mm) and minimum growth inhibition against S. epidermidis (12 mm). This study suggests that CuFe2O4-rGO-NCs as a high-efficacy antibacterial material and plays an important role in exhibiting higher sensitivity depending on concentrations. The results encourage that the synthesized CuFe2O4-rGO-NCs can be used as a promising material for the antibacterial activity and also for dye degradation in the water/wastewater treatment plants.

Bioactive Efficacy of Novel Carboxylic Acid from Halophilic Pseudomonas aeruginosa against Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) infections are increasingly causing morbidity and mortality; thus, drugs with multifunctional efficacy against MRSA are needed. We extracted a novel compound from the halophilic Pseudomonas aeruginosa using an ethyl acetate (HPAEtOAcE). followed by purification and structure elucidation through HPLC, LCMS, and 1H and 13C NMR, revealing the novel 5-(1H-indol-3-yl)-4-pentyl-1,3-oxazole-2-carboxylic acid (Compound 1). Molecular docking of the compound against the MRSA PS (pantothenate synthetase) protein was confirmed using the CDOCKER algorithm in BDS software with specific binding to the amino acids Arg (B:188) and Lys (B:150) through covalent hydrogen bonding. Molecular dynamic simulation of RMSD revealed that the compound-protein complex was stabilized. The proficient bioactivities against MRSA were attained by the HPAEtOAcE, including MIC and MBCs, which were 0.64 and 1.24 µg/mL, respectively; 100% biomass inhibition and 99.84% biofilm inhibition were observed with decayed effects by CLSM and SEM at 48 h. The hla, IrgA, and SpA MRSA genes were downregulated in RT-PCR. Non-hemolytic and antioxidant potential in the DPPH assay were observed at 10 mg/mL and IC50 29.75 ± 0.38 by the HPAEtOAcE. In vitro growth inhibition assays on MRSA were strongly supported by in silico molecular docking; Lipinski's rule on drug-likeness and ADMET toxicity prediction indicated the nontoxic nature of compound.