Dihydroxyacetone metabolism in Salinibacter ruber and in Haloquadratum walsbyi
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The extremely halophilic bacterium Salinibacter ruber inhabits saltern crystallizer ponds worldwide, together with the square archaeon Haloquadratum walsbyi. Cultures of Salinibacter have been shown to convert up to 20% of the glycerol added to a not previously characterized overflow product. We here identify this product of incomplete glycerol oxidation by Salinibacter as dihydroxyacetone. Genomic information suggests that H. walsbyi possesses an efficient uptake system for dihydroxyacetone, and we show here that dihydroxyacetone is indeed metabolized by Haloquadratum cultures, as well as by the heterotrophic prokaryotic community of the saltern crystallizer ponds in Eilat, Israel, dominated by Haloquadratum-like cells. In the absence of glycerol, Salinibacter also takes up dihydroxyacetone. Degradation of glycerol, produced in hypersaline lakes as an osmotic solute by the green alga Dunaliella salina may thus involve dihydroxyacetone as an intermediate, which can then be taken up by different types of heterotrophs present in the environment.
KeywordsSalinibacter Haloquadratum Dihydroxyacetone Glycerol Incomplete oxidation
We thank Mike Dyall-Smith and David Burns (Melbourne) for their gift of the Haloquadratum culture, and Lily Mana and Polina Khristo for their assistance in part of the experiments. We are further grateful to the Israel Salt Company in Eilat, Israel for allowing access to the salterns, and to the staff of the Interuniversity Institute for Marine Sciences of Eilat for logistic support. This study was supported by the Israel Science Foundation (grant no. 617/07).
- Ben-Amotz A, Avron M (1978) On the mechanism of osmoregulation in Dunaliella. In: Caplan SR, Ginzburg M (eds) Energetics and structure of halophilic microorganisms. Elsevier—North Holland Biomedical, Amsterdam, pp 529–541Google Scholar
- Brown AD, Lilley RM, Marengo T (1982) Osmoregulation in Dunaliella. Intracellular distribution of enzymes of glycerol metabolism. Z Naturforsch 37:1115–1123Google Scholar
- Burns DG, Janssen PH, Itoh T, Kamekura M, Li Z, Jensen G, Rodríguez-Valera FE, Bolhuis H, Dyall-Smith ML (2007) Haloquadratum walsbyi gen. nov., sp. nov., the square haloarchaeon of Walsby, isolated from saltern crystallizers in Australia and Spain. Int J Syst Evol Microbiol 57:387–392PubMedCrossRefGoogle Scholar
- Elevi Bardavid R, Khristo P, Oren A (2007b) Interrelationships between Dunaliella and halophilic prokaryotes in saltern crystallizer ponds. Extremophiles, published online 22nd December 2006; DOI 10.1007/s00792-006-0053-y
- Gimmler H, Lotter G (1982) The intracellular distribution of enzymes of the glycerol cycle in the unicellular alga Dunaliella parva. Z Naturforsch 37:1107–1114Google Scholar
- Legault BA, Lopez-Lopez A, Alba-Casado JC, Doolittle WF, Bolhuis H, Rodríguez-Valera F, Papke RT (2006) Environmental genomics of “Haloquadratum walsbyi” in a saltern crystallizer indicates a large pool of accessory genes in an otherwise coherent species. BMC Genomics 7:171PubMedCrossRefGoogle Scholar
- Mongodin EF, Nelson KE, Daugherty S, DeBoy RT, Wister J, Khouri H, Weidman J, Walsh DA, Papke RT, Sanchez Perez G, Sharma AK, Nesbø CL, MacLeod D, Bapteste E, Doolittle WF, Charlebois RL, Legault B, Rodríguez-Valera F (2005) The genome of Salinibacter ruber: convergence and gene exchange among hyperhalophilic bacteria and archaea. Proc Natl Acad Sci USA 102:18147–18152PubMedCrossRefGoogle Scholar
- Oren A, Gurevich P (1994) Production of d-lactate, acetate, and pyruvate from glycerol in communities of halophilic archaea in the Dead Sea and in saltern crystallizer ponds. FEMS Microbiol Ecol 14:147–156Google Scholar
- Tomlinson GA, Koch TK, Hochstein LI (1974) The metabolism of carbohydrates by extremely halophilic bacteria: glucose metabolism via a modified Entner Doudoroff pathway. Can J Microbiol 20:1085–1091Google Scholar