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Archives of Microbiology

, Volume 113, Issue 1–2, pp 131–138 | Cite as

The salt relations of Dunaliella

Further observations on glycerol production and its regulation
  • Lesley Joyce Borowitzka
  • David Stuart Kessly
  • Austin Duncan Brown
Article

Abstract

Dunaliella tertiolecta (marine) and D. viridis (halophilic) were each trained by serial transfer to growth at salt concentrations previously regarded as the other's domain. D. viridis then had a salt optimum at 1.0–1.5 M sodium chloride whereas that for D. tertiolecta was less than 0–2 M. Nevertheless D. tertiolecta grew faster than the halophil at all salt concentrations up to 3.5 M, the highest at which they were compared.

Both species accumulate glycerol, which is necessary for growth at elevated salinities and which responds in its content to water activity (a w ) rather than specifically to salt concentration. Variation in glycerol content is a metabolic process which occurs in the dark from accumulated starch as well as photosynthetically. Regulation of glycerol content by a w does not require protein synthesis. The NADP-specific glycerol dehydrogenase of each of the algae is likely to be directly involved in the regulation of glycerol content. Kinetic studies, together with those described in an earlier publication, show that the enzyme has regulatory properties, and that both glycerol and dihydroxyacetone act as effectors as well as reactants. A mechanism of the reaction is tentatively proposed.

Key words

Alga Compatible solute Dunaliella Glycerol Halophil Marine Osmoregulation Salt relations 

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Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Lesley Joyce Borowitzka
    • 1
    • 2
  • David Stuart Kessly
    • 1
    • 2
  • Austin Duncan Brown
    • 1
    • 2
  1. 1.School of MicrobiologyUniversity of New South WalesKensingtonAustralia
  2. 2.Department of BiologyUniversity of WollongongAustralia

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