Journal of Biosciences

, Volume 36, Issue 1, pp 55–67 | Cite as

Antipathogenic potential of marine Bacillus sp. SS4 on N-acyl-homoserine-lactone-mediated virulence factors production in Pseudomonas aeruginosa (PAO1)

  • K Syed Musthafa
  • V Saroja
  • S Karutha Pandian
  • A Veera RaviEmail author


Antipathogenic therapy is an outcome of the quorum-sensing inhibition (QSI) mechanism, which targets autoinducer-dependent virulent gene expression in bacterial pathogens. N-acyl homoserine lactone (AHL) acts as a key regulator in the production of virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1 and violacein pigment production in Chromobacterium violaceum. In the present study, the marine bacterial strain SS4 showed potential QSI activity in a concentration-dependent manner (0.5–2 mg/ml) against the AHL-mediated violacein production in C. violaceum (33–86%) and biofilm formation (33–88%), total protease (20–65%), LasA protease (59–68%), LasB elastase (36–68%), pyocyanin (17–86%) and pyoverdin productions in PAO1. The light and confocal laser scanning microscopic analyses confirmed the reduction of the biofilm-forming ability of PAO1 when treated with SS4 extract. Furthermore, the antibiofilm potential was confirmed through static biofilm ring assay, in which ethyl acetate extract of SS4 showed concentration-dependent reduction in the biofilm-forming ability of PAO1. Thus, the result of this study clearly reveals the antipathogenic and antibiofilm properties of the bacterial isolate SS4. Through 16S rDNA analysis, the strain SS4 was identified as Bacillus sp. (GenBank Accession Number: GU471751).


N-acyl homoserine lactone antipathogenic therapy Bacillus sp Chromobacterium violaceum Pseudomonas aeruginosa virulence genes 



N-acyl homoserine lactone


confocal laser scanning microscopy


dimethyl sulphoxide


Elastin-Congo red


exopolymeric substance


Luria Bertani


marine sediment bacterial


micro-titre plate


optical density


quorum sensing


quorum-sensing inhibition



The authors gratefully acknowledge the financial assistance rendered by University Grants Commission (UGC), New Delhi (F.No. 34-257/2008 (SR)), and the computational and bioinformatics facility provided by the Alagappa University Bioinformatics Infrastructure Facility (funded by the Department of Biotechnology, New Delhi; Grant No. BT/BI/25/001/2006).


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Copyright information

© Indian Academy of Sciences 2011

Authors and Affiliations

  • K Syed Musthafa
    • 1
  • V Saroja
    • 1
  • S Karutha Pandian
    • 1
  • A Veera Ravi
    • 1
    Email author
  1. 1.Department of BiotechnologyAlagappa UniversityKaraikudiIndia

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