title: Antifungal activity of Streptomyces sp. VITSTK7 and its synthesized Ag2O/Ag nanoparticles against medically important Aspergillus pathogens.
abstract: OBJECTIVE
  The aim of the present study was to assess the anti-Aspergillus activity of culture filtrate of Streptomyces sp. VITSTK7 and biologically synthesized Ag(2)O/Ag nanoparticles using the culture filtrate of VITSTK7.
  
  
  METHODS
  Silver nanoparticles were synthesized by biological reduction of silver nitrate using culture filtrate of Streptomyces sp. VITSTK7. The synthesized nanopaticles were characterized for surface plasma resonance peak, X-ray diffraction patterns, shape and size distribution. Inhibition of mycelial growth was used as an index of anti-Aspergillus activity of synthesized nanoparticles.
  
  
  RESULTS
  The synthesized nanoparticles were spherical shaped and monodespersive in nature and showed a single surface plasma resonance peak at 420 nm. X-ray diffraction patterns displayed typical peaks of crystalline silver oxide and size distribution histograms indicated production of 20-60-nm-size nanoparticles with average size of 35.2 nm. The synthesized nanoparticles showed anti-Aspergillus activity against Aspergillus niger, Aspergillus flavus and Aspergillus fumigatus with antifungal index in the range of 62-75%.
  
  
  CONCLUSIONS
  Thus the bioconversion of Ag(2)O/Ag nanoparticles by Streptomyces sp. VITSTK7 could be employed to control Aspergillus pathogenesis. The results of this study suggest that the green synthesis of Ag(2)O/Ag nanoparticles using marine Streptomyces sp. VITSTK7 yielded 27.9 nm sized particles with potential to act against pathogenic Aspergillus species.
authors.affiliation: Division of Biomolecules and Genetics, School of Biosciences & Technology, VIT University, Katpadi Road, Vellore 632 014, Tamil Nadu, India.
authors.forename: M
authors.initials: M
authors.lastname: Thenmozhi
authors.forename: K
authors.initials: K
authors.lastname: Kannabiran
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: V
authors.initials: V
authors.lastname: Gopiesh Khanna
mesh_terms: D000935:Antifungal Agents / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D001230:Aspergillus / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010087:Oxides / Q000737:chemistry / Q000378:metabolism; D010316:Particle Size; D018030:Silver Compounds / Q000737:chemistry / Q000378:metabolism; D013302:Streptomyces / Q000737:chemistry / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D000935:Antifungal Agents; D010087:Oxides; D018030:Silver Compounds; C040225:disilver oxide