Halomonas glaciei sp. nov. isolated from fast ice of Adelie Land, Antarctica

Abstract.

Eleven psychrophilic bacteria were isolated from a solid layer of fast ice in the middle of Pointe-Geologie Archipelago, Adelie Land, Antarctica. The 11 isolates based on the phenotypic characteristics, chemotaxonomic and phylogenetic analysis have been identified as members of the genus Halomonas. All the isolates at the 16S rDNA sequence level were identical, possessed the 15 conserved nucleotides of the family Halomonadaceae and four nucleotides of the genus Halomonas. Therefore, the 16S rDNA sequence of DD 39 was used for calculating the evolutionary distances and for phylogenetic analysis. It was observed that DD 39 formed a robust cluster with H. variabilis, from which it differed by 0.7%. Further DNA–DNA hybridization studies indicated low DNA–DNA homology (15%) between H. variabilis and DD 39. Between the 11 Antarctic isolates the homology was >85%. In addition it was observed that DD 39 was different from H. variabilis in that it was psychrophilic, could tolerate only up to 15% sodium chloride, could not hydrolyse esculin, could not reduce nitrate, was urease negative, could not utilize glycerol as a carbon source, and was resistant to ampicillin and erythromycin and sensitive to nalidixic acid. In addition, it also exhibited distinct differences with respect to high content of C_16:1 and low levels of cyclo-C_17:0 and cyclo-C_19:0. DD 39 also differed from all the other reported species of Halomonas with respect to many phenotypic characteristics. It is proposed therefore that DD 39 should be placed in the genus Halomonas as a new species that is Halomonas glaciei. The type strain of H. glaciei is DD 39^T (MTCC 4321; JCM 11692).