Aims:  The aim of the study was to isolate and characterize exopolysaccharide (EPS) produced by Vibrio harveyi strain VB23. Methods and Results:  Growth and EPS production by V. harveyi strain VB23, was studied in mineral salts medium supplemented with NaCl (1·5%) and glucose (0·2%). The rate of EPS production in batch cultures was highest during the late log phase of growth when compared with stationary growth phase. The exopolymer was recovered from the culture supernatant by using a cold ethanol precipitation–dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, proteins and sulfates. The purified EPS revealed prominent functional reactive groups, such as hydroxyl, carboxylic and amides, which correspond to a typical heteropolymeric polysaccharide and the EPS, also possessed good emulsification activity. The gas chromatographic analysis of an alditol acetate‐derivatized sample of EPS revealed that it is composed primarily of galactose and glucose. Minor components found were rhamnose, fucose, ribose, arabinose, xylose and mannose. Conclusions:  The EPS produced by V. harveyi strain VB23 is a heteropolysaccharide possessing good emulsification activity. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime‐like EPS. Significance and Impact of the Study:  This is the first report of EPS characterization in luminous V. harveyi bacteria, which describes the isolation and characterization of an EPS expressed by V. harveyi. The results of the study contributes significantly towards an understanding of the chemical composition and applications of the EPS in environmental biotechnology and bioremediation.

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Disease burden due to Streptococcus dysgalactiae subsp. equisimilis (group G and C streptococcus) is higher than that due to Streptococcus pyogenes among Mumbai school children Streptococcus pyogenes [group A streptococcus (GAS)], a human pathogen, and Streptococcus dysgalactiae subsp. equisimilis [human group G and C streptococcus (GGS/GCS)] are evolutionarily related, share the same tissue niche in humans, exchange genetic material, share up to half of their virulence-associated genes and cause a similar spectrum of diseases. Yet, GGS/ GCS is often considered as a commensal bacterium and its role in streptococcal disease burden is under-recognized. While reports of the recovery of GGS/GCS from normally sterile sites are increasing, studies describing GGS/GCS throat colonization rates relative to GAS in the same population are very few. This study was carried out in India where the burden of streptococcal diseases, including rheumatic fever and rheumatic heart disease, is high. As part of a surveillance study, throat swabs were taken from 1504 children attending 7 municipal schools in Mumbai, India, during 2006-2008. GAS and GGS/GCS were identified on the basis of b-haemolytic activity, carbohydrate group and PYR test, and were subsequently typed. The GGS/GCS carriage rate (166/1504, 11 %) was eightfold higher than the GAS carriage (22/1504, 1.5 %) rate in this population. The 166 GGS/GCS isolates collected represented 21 different emm types (molecular types), and the 22 GAS isolates represented 15 different emm types. Although the rate of pharyngitis associated with GGS/GCS is marginally lower than with GAS, high rates of throat colonization by GGS/GCS underscore its importance in the pathogenesis of pharyngitis.

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