GroEL PCR- RFLP - An efficient tool to discriminate closely related pathogenic Vibrio species.

Vibrio sp. are autochthonous to marine and estuarine waters. Several species of Vibrio are pathogens. It is of utmost importance to detect and discriminate the Vibrio sp. that are often involved in food and water borne infections. Since 16S rRNA based identification has limited utility in differentiating the closely related pathogenic species from non pathogenic species, we have evaluated the discriminatory power of groEL PCR-RFLP for identification of closely related Vibrio sp. Accordingly, in the current study, the efficiency of groEL PCR- RFLP for detection and accurate differentiation of known pathogens among Vibrio sp. such as V. cholerae, V. parahaemolyticus, V. vulnificus, V. mimicus, V. fluvialis, V. alginolyticus, V. anguillarum was evaluated. PCR amplified groEL gene fragment of each Vibrio sp. was digested separately using 5 restriction enzymes viz. Hha1, Rsa1, Alu1, Dde1 and Mbo1. The accuracy of the method was further validated by insilico restriction analysis of multiple strains of each species using NEBcutter. The method proved to be efficient for detection and differentiation of Vibrio species under study. Phylogenetic analysis also revealed groEL gene to be a better phylogenetic marker for Vibrio compared to 16S rRNA. Hence, the method can be employed for accurate detection of Vibrio sp. including the closely related species.

Screening and Characterization of Cold-Active ß-Galactosidase Producing Psychrotrophic Enterobacter ludwigii from the Sediments of Arctic Fjord.

Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and invaluable tool in various industrial applications. In the present study, bacterial isolates from the sediment samples of Kongsfjord, Norwegian Arctic, were screened for ß-galactosidase production. Among the isolates, KS25, KS85, KS60, and KS92 have shown good potential in ß-galactosidase production at 20 °C. 16SrRNA gene sequence analysis revealed the relatedness of the isolates to Enterobacter ludwigii. The optimum growth temperature of the isolate was 25 °C. The isolate exhibited good growth and enzyme production at a temperature range of 15-35 °C, pH 5-10. The isolate preferred yeast extract and lactose for the maximum growth and enzyme production at conditions of pH 7.0, temperature of 25 °C, and agitation speed of 100 rpm. The growth and enzyme production was stimulated by Mn2+ and Mg2+ and strongly inhibited by Zn2+, Ni2+, and Cu+. ß-Galactosidases with high specific activity at low temperatures are very beneficial in food industry to compensate the nutritional problem associated with lactose intolerance. The isolate exhibited a remarkable capability to utilize clarified whey, an industrial pollutant, for good biomass and enzyme yield and hence could be well employed in whey bioremediation.