Ionic Relations and Polyol Metabolism of Marine Fungi in Relation to Their Environment
The filamentous Hyphomycete Dendryphiella salina is the most extensively studied marine fungus. It has been shown by radiotracer flux analysis and X-ray microanalysis that the cytoplasmic concentrations of K, Na and Cl in mycelium gowing in 500 mM NaCl is of the order of 51–88, 74–139 and 160 mM respectively. There appears to be no accumulation of salt in vacuoles. In vivo studies of the effect of K and NaCl on enzymes are in keeping with the above values. Polyols make a major contribution to the osmotic ballast. The total concentration at any one external water potential is relatively constant. However the proportions of the four individual polyols, glycerol, erythritol, arabitol and mannitol may differ according to the solute generating the water potential. Growth of the marine yeast Debaryomyces hansenii in continuous culture suggests that polyols as well as producing compatible osmotic ballast are also, through their metabolism, involved in energy dissipation via futile cycles under conditions when growth becomes limited by conditions other than carbon supply. Primary and secondary transport in marine fungi is proton-and not sodium-based but a large volume cell wall may be involved in maintaining the appropriate proton electrochemical potential gradient.
KeywordsOsmotic Potential Soluble Carbohydrate Marine Fungus Marine Yeast Debaryomyces Hansenii
Unable to display preview. Download preview PDF.
- J. Kohlmeyer and E. Kohlmeyer, “Marine Mycology”, Academic Press, New York (1979)Google Scholar
- J. Kohlmeyer, Taxonomic studies of the marine Ascomycotina, in“The biology of marine fungi”, S. T. Moss, ed. Cambridge University Press, Cambridge (1986)Google Scholar
- D. H. Jennings, Cations and filamentous fungi: invasion of the sea and hyphal functioning, in“Ion transport in plants”, W. P. Anderson, ed. Academic Press, London (1973)Google Scholar
- D. H. Jennings, Polyol metabolism in fungi, Adv. Microbial Physiol., 25: 150 (1984)Google Scholar
- N. J. W. Clipson and D. H. Jennings, The role of sodium and potassium in the generation of the osmotic potential of the marine fungus Dendryphiella satina. Mycol. Res. (in press) (1990)Google Scholar
- A. Garrill and D. H. Jennings, unpublished data (1989)Google Scholar
- E. B. G. Jones and D. H. Jennings, The effect of cations on the growth of fungi. New Phytol. 64: 85 (1965)Google Scholar
- J. M. Davies, Ion transport in the marine fungus Dendryphiella satina, Ph.D. thesis, University of Liverpool (1989)Google Scholar
- R. M. Burke and D. H. Jennings, The effect of sodium chloride on the growth characteristics of the marine yeast Debaryomyces hansenii in batch and continuous culture under carbon limitation and under potassium limitation. Mycol. Res. (in press)(1990)Google Scholar
- D. W. Tempest and O. M. Neijssel, Growth yield values in relation to respiration, in“Diversity of bacterial respiratory systems, Vol. 1.” C. J. Knowles, ed. C.R.C. Press, Boca Raton, (1980)Google Scholar
- D. H. Jennings and R. M. Burke, Compatible solutes - the mycological dimension and their role as physiological buffering agents. New Phytol. submitted. (1990)Google Scholar