Antimicrobial activity of silver nanoparticles biosynthesized by Streptomyces spp.

Bioproduction options for nanoparticles are becoming a highly significant subject, with environmental and economic benefits over physical and chemical processes. The purpose of the current study is to detect the antimicrobial activity of chitosan-Graphene oxide nanoparticles that include The Minimum Inhibitory Concentration (MIC) is a method of determining antibacterial activity, Antibiofilm Activity by Tissue culture plate method, Antioxidant activity, and finally the hemolysis activity of mixing nanoparticles CS-GO that synthesis biologically. the result of Antibacterial activity showed the ID50 for inhibition is at a concentration (1 mg/ml), while the Antibiofilm activity result shows the high concentration of CS-GO nanoparticles (16 mg/ml) showed the higher activity in inhibition of biofilm formation while the less concentration (0.6mg/ml) appeared very low inhibition activity on biofilm formation. The antioxidant activity of nanoparticles showed the high scavenging ability at a concentration (600 mg/ml) as (54.06%) while the less concentration (100mg/ml) appeared scavenger ability as (29.42%) also the hemolysis activity on CS-GO nanoparticles on blood showed different ability at different concentration, the preferred concentration (1mg/ml) show no hemolysis on blood.

Metals that contain nanomaterials have the potential to be employed in controlling different kinds of infection, however, very limited information is known about their antibacterial properties. This study has been done to investigate the nanosynthesis titanium nanoparticles (TiNPs) using Streptococcus thermophilus and analyzing their biological actions as antibacterial. The bacterial isolates identified using universal primers 16S rRNA; then the 16S rRNA gene nucleotide sequences were aligned with the nucleotide sequences of strains obtained from the GeneBank through the software CLUSTAL X (version 1.82). Titanium nanoparticles were nanosynthesized by adding 0.025M titanium dioxide (TiO2) into cell-free supernatant for Streptococcus thermophilus. TiO2 was used as a precursor for nanobiosynthesis TiNPs. The formation of TiNPs was indicated by the color alteration of the solution from the light brown into dark brown indicates for the production of TiNPs. The Characterization of nanobiosynthesis was accomplished with UV-Visible (absorbance at 377nm), Scanning Electron Microscope, X-ray diffraction, Atomic Force Microscope, Energy-dispersive X-ray spectroscopy was used to distinguish the dimension, form (spherical) by SEM, dispersal (homogenous) and elemental analysis of nanoparticles. Biogenic TiNPs have displayed antibacterial and antibiofilm activity against both multidrugresistant Klebsiella pneumonia and Staphylococcus aureus. As an antibacterial activity, the TiNPs inhibited significantly K.pneumoniae (20 mm) with concentration (500 μg/ml), and S. aureus (16 mm) with the same concentration and increasing the concentration of TiNPs the inhibition zone increased. While as antibiofilm activity of TiNPs using the tube method, the tubes containing bacterial suspension K.pneumoniae and S.aureus with TiNPs, the results demonstrated that the biofilm formation was prevented and removed by the effect of TiNPs.

Due to the emergence of high virulence pathogenic strains of bacteria that are resistant to most antibiotics, this study was conducted to find alternative materials for antibiotics or work with antibiotics against bacterial strains that are resistant to antibiotics. in this study, we used bacterially reduced graphene oxide (BrGO) for this purpose and through the experiment showed that Graphene oxide (GO) nanosheets can biologically reduce by Bacillus clausii by reaction GO with cell free supernatant, where the reaction mixture incubates for 72hrs at 37C° in a shaking incubator. The general properties of reduced Graphene Oxide (rGO) nanosheets by B. clausii were determined through Ultraviolet–visible (UV-vis) Spectroscopy, Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), and X-Ray Diffraction (XRD) analysis. The results showed the successful bacterial synthesis of rGO nanosheets via removal of water molecules and oxygen functional groups from interlayer of GO. So, the reduced Graphene oxide by Bacillus clausii considered excellent and eco-friendly. BrGO nanosheets exhibited potent noticeable antibacterial activity at different concentrations (0.1, 0.5, 1, 5, 10 mg/ml) against both Gram (-ve) and Gram (+ve) tested MDR uropathogenic isolates when used alone or at combining with other antibiotics. also the results showed that potent growth inhibition zones was increased with increasing concentrations of BrGO.

Secondary metabolites (SM) products permanently played an important role in medicine; fungi metabolites have increasingly become major players in recent pharmaceutical discovery in particular antimicrobial agents. The aim of study was to prepare and characterize of potential biological extract of culture filtrate of Trichophyton rubrum and tested as antibacterial, antioxidant agents. Local isolates of a dermatophyte T. rubrum were used and examined for production of SM. Extracts were checked for physical and chemical characterization using Fourier transform infrared spectrophotomete and HPLC and their cytotoxicity using a sensitive in-vitro brine shrimp lethality bioassay. The results revealed the isolation, preparation and characterization of different components of SM, included especially kojic acid, fusidic acid, amides and sulfones which gave antibacterial and antioxidant properties. In conclusion, the current study established the ability of a dermatophyte, T. rubrum to produce antibiotic-like substances, especially the sulfones which not isolated and recorded previously from T. rubrum.