title: Disruption of microbial biofilms by an extracellular protein isolated from epibiotic tropical marine strain of Bacillus licheniformis.
abstract: BACKGROUND
  Marine epibiotic bacteria produce bioactive compounds effective against microbial biofilms. The study examines antibiofilm ability of a protein obtained from a tropical marine strain of Bacillus licheniformis D1.
  
  
  RESULTS
  B. licheniformis strain D1 isolated from the surface of green mussel, Perna viridis showed antimicrobial activity against pathogenic Candida albicans BH, Pseudomonas aeruginosa PAO1 and biofouling Bacillus pumilus TiO1 cultures. The antimicrobial activity was lost after treatment with trypsin and proteinase K. The protein was purified by ultrafiltration and size-exclusion chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis revealed the antimicrobial agent to be a 14 kDa protein designated as BL-DZ1. The protein was stable at 75°C for 30 min and over a pH range of 3.0 to 11.0. The sequence alignment of the MALDI-fingerprint showed homology with the NCBI entry for a hypothetical protein (BL00275) derived from B. licheniformis ATCC 14580 with the accession number gi52082584. The protein showed minimum inhibitory concentration (MIC) value of 1.6 µg/ml against C. albicans. Against both P. aeruginosa and B. pumilus the MIC was 3.12 µg/ml. The protein inhibited microbial growth, decreased biofilm formation and dispersed pre-formed biofilms of the representative cultures in polystyrene microtiter plates and on glass surfaces.
  
  
  CONCLUSIONS
  We isolated a protein from a tropical marine strain of B. licheniformis, assigned a function to the hypothetical protein entry in the NCBI database and described its application as a potential antibiofilm agent.
authors.affiliation: Institute of Bioinformatics and Biotechnology, University of Pune, Pune, India.
authors.forename: Devendra H
authors.initials: DH
authors.lastname: Dusane
authors.forename: Samir R
authors.initials: SR
authors.lastname: Damare
authors.forename: Yarlagadda V
authors.initials: YV
authors.lastname: Nancharaiah
authors.forename: N
authors.initials: N
authors.lastname: Ramaiah
authors.forename: Vayalam P
authors.initials: VP
authors.lastname: Venugopalan
authors.forename: Ameeta Ravi
authors.initials: AR
authors.lastname: Kumar
authors.forename: Smita S
authors.initials: SS
authors.lastname: Zinjarde
mesh_terms: D001407:Bacillus / Q000378:metabolism* / Q000472:pathogenicity; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000502:physiology*; D018441:Biofilms; D002176:Candida albicans; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D008386:Marine Biology; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014462:Ultrafiltration
chemical_list: D001426:Bacterial Proteins