Antipathogenic potential of marine Bacillus sp. SS4 on N-acyl-homoserine-lactone-mediated virulence factors production in Pseudomonas aeruginosa (PAO1)
- 367 Downloads
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).
KeywordsN-acyl homoserine lactone antipathogenic therapy Bacillus sp Chromobacterium violaceum Pseudomonas aeruginosa virulence genes
N-acyl homoserine lactone
confocal laser scanning microscopy
marine sediment bacterial
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).
- Ausubel F, Brent R, Kingston R, Moore D, Seidman J and Struhl K 1990 Current protocols in molecular biology (New York: John Wiley)Google Scholar
- Brint JM and Ohman DE 1995 Synthesis of multiple exoproducts in Pseudomonas aeruginosa is under the control of RhlR-RhlI, another set of regulators in strain PAO1 with homology to the autoinducer-responsive LuxR-LuxI family. J. Bacteriol. 24 7155–7163Google Scholar
- Manefield M, de Nys R, Kumar N, Read R, Givskov M, Steinberg P and Kjelleberg S 1999 Evidence that halogenated furanones from Delisea pulchra inhibit acylated homoserine lactone (AHL)-mediated gene expression by displacing the AHL signal from its receptor protein. Microbiology 145 283–291PubMedCrossRefGoogle Scholar