Correlation between phylogenetic structure and function: examples from deep-sea Shewanella

The genus Shewanella is one of the typical deep-sea bacterial genera. Two i solated deep-sea Shewanella species, Shewanella benthica and Shewanella vio lacea, were found to be able to grow better under high hydrostatic pressure conditions than at atmospheric pressure. These species are not only piezop hilic (barophilic), but also psychrophilic. Many psychrophilic and psychrot olerant Shewanella species have been isolated and characterized from cold e nvironments, such as seawater in Antarctica or the North Sea. Some of these cold-adapted Shewanella were shown to be piezotolerant, meaning that growt h occurs in a high-pressure habitat. In this review, we propose that two ma jor sub-genus branches of the genus Shewanella should be recognized taxonom ically, one group characterized as high-pressure cold-adapted species that produce substantial amounts of eicosapentaenoic acid, and the other group c haracterized as mesophilic pressure-sensitive species. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. A ll rights reserved.