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OSMOREGULATION IN THE MARINE DIATOM CYLINDROTHECA FUSIFORMIS 1
Author(s) -
Paul John S.
Publication year - 1979
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1979.00280.x
Subject(s) - biology , diatom , osmotic concentration , mannose , osmotic pressure , salinity , osmoregulation , intertidal zone , sugar , sorbitol , hydrostatic pressure , polysaccharide , biophysics , botany , biochemistry , ecology , physics , thermodynamics
A mechanism for the regulation of internal osmolarity in the diatoms (Bacillariophyta) was investigated using the intertidal lestuarian pennate diatom, Cylindrotheca fu‐siformis Reimann & Lewin. The intracellular pools of the free sugar, mannose, and its respective polymer, poly‐mannose, were found to be in a dynamic equilibrium which rapidly responds to changes in external osmotic pressure. Increasing the salinity shifts the steady state in the direction of free mannose, while decreasing the salinity stimulates polymerization of the free mannose to its polysaccharide. The mechanism requires a response of certain key enzymes to osmotic pressure rather than to levels of any particular ion since increasing the external osmolarity with an organic solute (sorbitol) was as effective in eliciting a response as using inorganic ions.