Chemical characterization of exopolysaccharides from Antarctic marine bacteria

Type Article
Date 2005-05
Language English
Author(s) Nichols Carol1, Lardiere Sandrine2, Bowman John3, Nichols Peter4, Gibson John4, Guezennec Jean2
Affiliation(s) 1 : Univ Tasmania, Ctr Marine Sci, Sch Agr Sci, Hobart, Tas 7000, Australia.
2 : Inst Francais Rech Exploitat Mer, Ctr Brest, F-29280 Plouzane, France.
3 : Univ Tasmania, Australian Food Safety Ctr, Hobart, Tas 7000, Australia.
4 : Commonwealth Sci & Ind Res Org, Marine Res, Hobart, Tas 7000, Australia.
Source Microbial Ecology (0095-3628) (Springer), 2005-05 , Vol. 49 , N. 4 , P. 578-589
DOI 10.1007/s00248-004-0093-8
WOS© Times Cited 101
Keyword(s) Marine particulates, Sea ice, Marine bacteria, Antarctica, Exopolysaccharides
Abstract Exopolysaccharides (EPS) may have an important role in the Antarctic marine environment, possibly acting as ligands for trace metal nutrients such as iron or providing cryoprotection for growth at low temperature and high salinity. Ten bacterial strains, isolated from Southern Ocean particulate material or from sea ice, were characterized. Whole cell fatty acid profiles and 16S rRNA gene sequences showed that the isolates included representatives of the genera Pseudoalteromonas, Shewanella, Polaribacter, and Flavobacterium as well as one strain, which constituted a new bacterial genus in the family Flavobacteriaceae. The isolates are, therefore, members of the "Gammaproteobacteria" and Cytophaga-Flexibacter-Bacteroides, the taxonomic groups that have been shown to dominate polar sea ice and seawater microbial communities. Exopolysaccharides produced by Antarctic isolates were characterized. Chemical composition and molecular weight data revealed that these EPS were very diverse, even among six closely related Pseudoalteromonas isolates. Most of the EPS contained charged uronic acid residues; several also contained sulfate groups. Some strain produced unusually large polymers (molecular weight up to 5.7 MDa) including one strain in which EPS synthesis is stimulated by low temperature. This study represents a first step in the understanding of the role of bacterial EPS in the Antarctic marine environment.
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