European Journal of Biomedical and Pharmaceutical Sciences

EVALUATION OF EXO POLYSACCHARIDE PRODUCTION BY MARINE BACTERIUM VIBRIO HARVEYI

D. Hensen Jeba Jose*, G. Ramathan, T. Vinodh Kumar and M. Vignesh

ABSTRACT

Vibrios are one of the most important pathogens for reared aquatic organisms such as penaeid shrimps, several fish species and molluscs, and also for corals. Some of the luminescent Vibrios, which include Vibrio cholerae, V. fischeri, V. harveyi, V. logei, V. splendidus, V. mediterranei, V. orientalis, Photobacterium leiognathi and P. phosphoreum have been implicated principally with disease outbreaks in shrimp larviculture facilities, and to a lesser degree in grow-out ponds. V. fischeri colonizes the squid light organ and provides bioluminescence for the squid to use as counter shooting in order to evade predators. In return the bacteria gain a protected nutrient environment. The discovery of N-acylhomoserine lactones as quorum sensing signals was first made in V. fischeri is the paradigm of gram-negative QS systems even though it is not fond in all vibrios.Fish pathogen Vibrio harveyi was isolated from naturally diseased fishes collected from local fish market. The presence of disease symptoms on represented by skin disease and scale detachment. Some fishes shows enlargement of internal organs. Production of exopolysaccharide (EPS) by Vibrio harveyi were determined with different cultivation parameters such as different NaCl, pH and utilization of carbon sources. Among the parameters screened pH 6 and 7, 5% NaCl and the carbon source sucrose highly influence the growth and EPS production by Vibrio harveyi.Vibrio harveyi also screened for their response to commercially availed antibiotics such as Neomycin, Ampicillin, Penicillin-G and Vancomycin. Among the antibiotic Neomycin strongly inhibit (10mm) of fish pathogen vibrio.Molecular characterization of the Vibrio harveyi isolates was also done by the sequence analysis and submitted at accession number was obtained.

Keywords: Vibrio harveyi, Fish pathogen, Neomycin, EPS (Exopolysaccharides).