New insights into microbial adaptation to extreme saline environments

P Vauclare,D Madern,F Gabel,G Zaccai,B Franzetti,E Girard,M Ollivier,M.-C Maurel

doi:10.1051/bioconf/20140202001

Abstract

Extreme halophiles are microorganisms adapted to low water activity living at the upper salt concentration that life can tolerate. We review here recent data that specify the main factors, which determine their peculiar salt-dependent biochemistry. The data suggested that evolution proceeds by stage to modify the molecular dynamics properties of the entire proteome. Extreme halophiles therefore represent tractable models to understand how fast and to what extent microorganisms adapt to environmental changes. Halophiles are also robust organisms, capable to resist multiple stressors. Preliminary studies indicated that they have developed a cellular response specifically aimed to survive when the salt condition fluctuates. Because of these properties halophilic organisms deserve special attention in the search for traces of life on other planets.

Highlights

Microbes are the most diverse and abundant organisms on earth
Extremophiles deserve a special interest in planetary sciences and astrobiology and represent tractable model to understand the evolution of life with respect to environmental changes as well as to dissect the cellular stress response [9]
Sensitivity towards physico-chemical stress will vary from one protein to another and the adaptation of a microorganism to extreme condition could be limited by the fragility of a reduced set of proteins or biological functions only

Summary

The extreme biosphere

Microbes are the most diverse and abundant organisms on earth. A large part of the earth environment is exposed to physico-chemical conditions that, for a long time, were thought to be incompatible with life. Extremophiles possess remarkable resilience and stress resistance capacities For all these reasons, extremophiles deserve a special interest in planetary sciences and astrobiology and represent tractable model to understand the evolution of life with respect to environmental changes as well as to dissect the cellular stress response [9]. Extremophiles deserve a special interest in planetary sciences and astrobiology and represent tractable model to understand the evolution of life with respect to environmental changes as well as to dissect the cellular stress response [9]

Extremophilic life adaptation: general concepts and future challenges

Halophiles: model organisms in exobiology and environmental microbiology

Water in cells

Halophilic protein adaptation

Cellular responses to fluctuating salt environments

Conclusions