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Abstract

Qualitative analysis with colistin and streptomycin on the growth curves of the P. syringae Lz4W shows that the growth was resumed to exponential stage after delayed lag phase at a lethal antibiotic concentration, when supplied externally with prepared OMVs from the same organism. This result shows that the OMV?s may play an important in antibiotic resistance. In order to understand the functions of the OMVs, a detailed study was undertaken to analyze different components present in the OMVs. We have characterized different components of OMVs from an Antarctic bacterium Pseudomonas syringae Lz4W. The OMVs were prepared from P. syringae Lz4W and their size was determined by Transmission Electron Microscopy (TEM) and dynamic light scattering. The phospholipids from these MVs were characterized by a combination of MALDI-MS and fatty-acid methyl ester (FAME) analysis on GC-MS. The OMVs were also found to contain LPS. The proteins of OMVs were separated by 1D-gel and then analyzed by nano LC-MALDI-TOF/TOF and LC-ESI-MS/MS (Orbitrap). Mass spectrometric data was analyzed by Mascot and Sequest softwares respectively. Since the genome sequence of this organism is not known, a database was prepared from different Pseudomonas species and used to identify the proteins. The subcellular localizations of these proteins were predicted by using Psortb V3 software. Along with inner membrane, periplasmic and outer membrane proteins, we identified many cytoplsmic proteins/enzymes segregating in to the OMVs. These proteins are implicated in their functions. Attempts were also made to understand the mechanism of protection to bacteria by the OMVs using fluorescent probe NPN.

Biography

Medicharla V. Jagannadham completed his PhD in the year 1998 and working as a Scientist for the past 22 years at Centre for Cellular and Molecular Biology, Hyderabad, India. He has published more than 35 research papers in internationally reputed Journals. He published a monograph on the ?Membrane proteins of an Antarctic bacterium Pseudomonas syringae? He is a member of several learned scientific societies such as Society of Biological Chemists (India), The American Society for Biochemistry and Molecular Biology. His research interests are developing proteomics technologies and studies on the functions of the outer membrane vesicles of bacteria.