title: Antimicrobial and immunomodulatory efficacy of extracellularly synthesized silver and gold nanoparticles by a novel phosphate solubilizing fungus Bipolaris tetramera.
abstract: BACKGROUND
  Particulates of nanometers size have occupied a significant area in the field of medicinal and agricultural purposes due to their large surface-to-volume ratio and exceptional physicochemical, electronic and mechanical properties. Myconanotechnology, an interface between mycology and nanotechnology is budding nowadays for nanoparticle-fabrication using fungus or its metabolites. In the present study, we have isolated and characterized a novel phosphate solubilizing fungus B. tetramera KF934408 from rhizospheric soil. This phosphatase releasing fungus was subjected to extracellular synthesis of metal nanoparticles by redox reaction.
  
  
  RESULTS
  Silver (AgNPs) and gold nanoparticles (AuNPs) were characterized by dynamic light scattering and transmission electron microscopic analysis. The formulated AgNPs were irregular shaped with a size ranging between 54.78 nm to 73.49 nm whereas AuNPs were spherical or hexagonal, with a size of 58.4 and 261.73 nm, respectively. The nanoparticles were assessed for their antibacterial and antifungal efficacy. The results showed effective antimicrobial activity of AgNPs against Bacillus cereus, Staphylococcus aureus, Enterobacter aeroginosa and Trichoderma sp. at higher concentrations, however, AuNPs possessed only moderate antibacterial efficacy while they found no antifungal activity. Cytotoxicity analysis of nanoparticles on J774 and THP1 α cell lines revealed the dose dependence in case of AgNPs, while AuNPs were non-toxic at both low and high doses. Furthermore, significant elevation of intracellular ROS was observed after 4 h of incubation with both the nanoparticles. The capping of fungal proteins on the particulates might be involved in the activities demonstrated by these inert metal nanoparticles.
  
  
  CONCLUSIONS
  In conclusion, the findings showed that the metal nanoparticles synthesized by fungus B. tetramera could be used as an antimicrobial agents as well as cost effective and nontoxic immunomodulatory delivery vehicle.
authors.affiliation: Department of Biosciences, Integral University, Lucknow, 226026, India. fatimafaria45@gmail.com.
authors.forename: Faria
authors.initials: F
authors.lastname: Fatima
authors.affiliation: Department of Biosciences, Integral University, Lucknow, 226026, India. pbajpai@iul.ac.in.
authors.forename: Preeti
authors.initials: P
authors.lastname: Bajpai
authors.affiliation: Department of Biosciences, Integral University, Lucknow, 226026, India. pathak_neelam@yahoo.com.
authors.forename: Neelam
authors.initials: N
authors.lastname: Pathak
authors.affiliation: Division of Toxicology, Central Drug Research Institute, Lucknow, 226031, India. ssj3010@gmail.com.
authors.forename: Sarika
authors.initials: S
authors.lastname: Singh
authors.affiliation: Division of Environmental Carcinogenesis, Indian Institute of Toxicology Research, Lucknow, 226026, India. bajn2005@gmail.com.
authors.forename: Shivam
authors.initials: S
authors.lastname: Priya
authors.affiliation: Department of Biotechnology, Delhi Technological University, Delhi, 110042, India. srsmitarastogi@gmail.com.
authors.forename: Smita Rastogi
authors.initials: SR
authors.lastname: Verma
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D000935:Antifungal Agents / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D021902:Enterobacter aerogenes / Q000187:drug effects / Q000254:growth & development; D005656:Fungal Proteins / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007155:Immunologic Factors / Q000096:biosynthesis / Q000494:pharmacology; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D036103:Nanotechnology / Q000379:methods; D010084:Oxidation-Reduction; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000819:agonists / Q000378:metabolism; D004718:Saccharomycetales / Q000737:chemistry / Q000201:enzymology*; D012834:Silver / Q000737:chemistry; D012995:Solubility; D014242:Trichoderma / Q000187:drug effects / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D005656:Fungal Proteins; D007155:Immunologic Factors; D010710:Phosphates; D017382:Reactive Oxygen Species; D012834:Silver; D006046:Gold; D010744:Phosphoric Monoester Hydrolases