title: Rhamnolipid (RL) from Pseudomonas aeruginosa OBP1: a novel chemotaxis and antibacterial agent.
abstract: In the present study, the interaction of rhamnolipid produced by Pseudomonas aeruginosa OBP1 with the cell surfaces of Staphylococcus aureus (MTCC 3160) and Klebsiella pneumoniae (MTCC 618) were studied. Rhamnolipid concentration below critical micelle concentration (CMC) did not exhibit significant antibacterial activity. However, on increasing rhamnolipid concentration beyond CMC a prominent antibacterial activity was observed. The results demonstrated different degree of rhamnolipid interaction with both the bacteria. This might be due to the changes in their cell wall composition. The antibacterial activity determined by minimum inhibitory concentration (MIC). The antibacterial activity is prominent within 30 min of incubation. The antibacterial property of rhamnolipid was effective in all tested pH levels (5-9). The rhamnolipid was effective in almost all tested pH levels and showed better chemoattractant property against both the tested bacteria in comparison to glucose. The increase in the membrane permeability was evidenced by increase in the release of protein, enhancement in cell surface hydrophobicity and raises in the retention of crystal violet dye. Further, leakage of 260 nm absorbing intracellular materials, fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis confirmed the disruptive action of rhamnolipid. The above evidences support the idea that rhamnolipid significantly alters the cell membrane/envelop that leads to cell damage and enhances membrane permeability. Such activity of rhamnolipid could be used as an additive in the formulation of antibiotic and other antimicrobial agents for enhancing the effectiveness of chemotherapeutics.
authors.affiliation: Department of Molecular Biology and Biotechnology, Tezpur (Central) University, Napaam, Tezpur 784028, Assam, India.
authors.forename: P
authors.initials: P
authors.lastname: Bharali
authors.forename: J P
authors.initials: JP
authors.lastname: Saikia
authors.forename: A
authors.initials: A
authors.lastname: Ray
authors.forename: B K
authors.initials: BK
authors.lastname: Konwar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002633:Chemotaxis / Q000187:drug effects*; D015169:Colony Count, Microbial; D006017:Glycolipids / Q000302:isolation & purification* / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D007711:Klebsiella pneumoniae / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D006017:Glycolipids; C418382:rhamnolipid; D013307:Streptomycin