Regulation of osmolyte synthesis in the moderate halophile Halobacillus halophilus

• Applicant: Professor Dr. Volker Müller
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 150413131

• Final Report Year: 2014

Final Report Abstract

Although we did not get to far with respect to solving the most interesting question: what is the molecular basis of the chloride dependence of H. halophilus, we feel that we were quite successfull and have accomplished to publish a number of papers on different aspects on the physiology of H. halophilus. Our initial hypothesis that the glutamine synthetase GlnA2 senses and responds to chloride had to be revisited. It took us some time and the development of a genetic system to realize that. However, our initial observation that a glutamytransferase activity is salt-dependent and chloride stimulated is still valid and has been reproduced by several students. Using the genetic system we were then able to screen for other enzymes that catalyze the salt-dependent glutamytransferase activity as observed in whole cells but the potential candidates analzyed so far turned out to be the false ones. Currently, this is the search for the needle in the haystack and, therefore, we currently refrain from continuation of the project.

Publications

• (2009) Structure, function and biosynthesis of carotenoids in the moderately halophilic bacterium Halobacillus halophilus. Arch. Microbiol. 191 : 95-104
  Köcher, S., Breitenbach, J., Müller, V., Sandmann, G.
  
• (2010) Exploring research frontiers in microbiology: recent advances in halophilic and thermophilic extremophiles. Res. Microbiol. 161 : 506-514
  Averhoff, B., Müller, V.
  
• (2010) Hydroxy-3,4-dehydro-apo-8'-lycopene and methyl hydroxy-3,4-dehydro-apo-8'-lycopenoate, novel C30 carotenoids produced by a mutant of marine bacterium Halobacillus halophilus. J. Antibiot. (Tokyo) 63 : 291-295
  Osawa, A., Ishii, Y., Sasamura, N., Morita, M., Köcher, S., Müller, V., Sandmann, G., Shindo, K.
  
• (2011) Adapting to changing salinities: biochemistry, genetics and regulation in the moderately halophilic bacterium Halobacillus halophilus. In: Extremophiles Handbook (Horikoshi, K; Bull, A; Robb, F; Stetter, K. and Antranikian, G., eds), Springer, New York, Heidelberg, pp 384-400
  Köcher, S., Müller, V.
  
• (2011) Development of a genetic system for the moderately halophilic bacterium Halobacillus halophilus: Generation and characterization of mutants defect in the production of the compatible solute proline. Environ. Microbiol. 13 : 2122-2131
  Köcher, S., Averhoff, B., Müller, V.
  
• (2011) Proline metabolism in the moderately halophilic bacterium Halobacillus halophilus: differential regulation of isogenes in proline utilization. Environ. Microbiol. Reports 3 : 443-448
  Köcher, S., Tausendschön, M., Thompson, M., Saum S.H., Müller, V.
  
• (2011) The nature and function of carotenoids in the moderately halophilic bacterium Halobacillus halophilus. In: Halophiles and Hypersaline Environments: Current Research and Future Trends (Ventosa, A., Oren, A. Ma, Y.,eds), Springer, New York, Heidelberg, pp 303-318
  Köcher, S., Müller, V.
  
• (2012) Adjusting membrane lipids under salt stress: the case of the moderate halophilic organism Halobacillus halophilus. Environ. Microbiol. 15 : 1078-1087
  Lopalco, P., Angelini, R., Lobasso, S., Köcher, S., Thompson, M., Müller, V., Corcelli, A.
  (See online at https://doi.org/10.1111/j.1462-2920.2012.02870.x)
• (2012) Chloride and organic osmolytes: a hybrid strategy to cope with elevated salinities by the moderately halophilic, chloride-dependent bacterium Halobacillus halophilus. Environ. Microbiol. 15 : 1619-1633
  Saum, S.H., Pfeiffer, F., Palm, P., Rampp, M., Schuster, S.C., Müller, V., Oesterhelt, D.
  (See online at https://doi.org/10.1111/j.1462-2920.2012.02770.x)
• (2013) Bioenergetics of the moderately halophilic bacterium Halobacillus halophilus: composition and regulation of the respiratory chain. Appl. Environ. Microbiol. 79 : 3839-3846
  Pade, N., Köcher, S., Roeßler, M., Hänelt, I., Müller, V.
  (See online at https://doi.org/10.1128/AEM.00855-13)
• (2013) Microbial adaptation to saline environments: Lessons from the genomes of Natranaerobius thermophilus and Halobacillus halophilus. In: Halophiles: Genetics and Genomes (Papke, R.T., Oren, A., eds.), Caister Academic Press, Norfolk, UK
  Mesbah, N.M., Hänelt, I., Zhao, B. and Müller, V.
  
• (2013) Molecular mechanisms of adaptation of the moderately halophilic bacterium Halobacillus halophilus to its environment. Life 3 : 234-243
  Hänelt, I., Müller, V.
  
• (2014) An alternative, arginase-independent pathway for arginine metabolism in Kluyveromyces lactis involves guanidinobutyrase as a key enzyme. Mol. Microbiol.93 : 369-389
  Romagnoli, G., Verhoeven, M.D., Mans, R., Fleury Rey, Y., Bel-Rhlid, R., van den Broek, M., Maleki Zefar, R., Ten Pierick, A., Thompson, M., Müller, V., Wahl, S.A., Pronk, J.T., Daran J.M.
  (See online at https://doi.org/10.1111/mmi.12666)
• (2014) Glutamine synthetase 2 is not essential for biosynthesis of compatible solutes in Halobacillus halophilus. Front. Microbiol. 5 : 168
  Shiyan, A., Thompson, M., Köcher, S., Tausendschön, M., Santos, H., Hänelt, I., Müller, V.
  (See online at https://doi.org/10.3389/fmicb.2014.00168)