Regulation of osmoadaptation in the moderate halophile Halobacillus halophilus : chloride, glutamate and switching osmolyte strategies

  • The moderate halophile Halobacillus halophilus is the paradigm for chloride dependent growth in prokaryotes. Recent experiments shed light on the molecular basis of the chloride dependence that is reviewed here. In the presence of moderate salinities Halobacillus halophilus mainly accumulates glutamine and glutamate to adjust turgor. The transcription of glnA2 (encoding a glutamine synthetase) as well as the glutamine synthetase activity were identified as chloride dependent steps. Halobacillus halophilus switches its osmolyte strategy and produces proline as the main compatible solute at high salinities. Furthermore, Halobacillus halophilus also shifts its osmolyte strategy at the transition from the exponential to the stationary phase where proline is exchanged by ectoine. Glutamate was found as a second messenger" essential for proline production. This observation leads to a new model of sensing salinity by sensing the physico-chemical properties of different anions.

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Author:Stephan H. Saum, Volker MüllerORCiD
Parent Title (German):Saline Systems
Document Type:Article
Date of Publication (online):2008/08/25
Year of first Publication:2008
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2008/08/25
© 2008 Saum and Muller, licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited:
Source:Saline Systems 2008, 4:4 doi:10.1186/1746-1448-4-4
Institutes:Biowissenschaften / Biowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung 2.0