Osmoadaptation in Bacteria and Archaea: Common Principles and Differences

Environ Microbiol. 2001 Dec;3(12):743-54. doi: 10.1046/j.1462-2920.2001.00252.x.


The availability of water is the most important prerequisite for life of any living cell, and exposure of cells to hypersaline conditions always threatens the cells with a drastic loss of water. To re-establish the essential turgor pressure, cells increase the water activity of their cytoplasm by accumulation of compatible solutes, either by synthesis or by uptake. The ability to respond to increasing osmolality is well conserved in all three lines of descent and, here, we compare the osmoadaptive strategies of Bacteria and Archaea. The temporal sequence of events after an osmotic upshock will be discussed, with a focus on the most rapid response, notably the mechanisms of transport activation at the protein level, and different signals for osmolality will be compared. The spectrum of compatible solutes used by different organisms is rather diverse and a comparison of 'bacterial' and 'archaeal' compatible solutes will be given.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptation, Physiological
  • Archaea / physiology*
  • Bacterial Physiological Phenomena*
  • Homeostasis
  • Molecular Structure
  • Signal Transduction / physiology
  • Solutions
  • Water / metabolism*
  • Water-Electrolyte Balance / physiology*


  • Solutions
  • Water