Variations in inorganic carbon acquisition mechanisms in a marine diatom (Phaeodactylum tricornutum)

Variations in the mechanisms of inorganic carbon acquisition have been investigated in eleven different strains of the marine diatom Phaeodactylum tricornutum Bohlin obtained from three culture collections. The presence of external and internal carbonic anhydrase (CA) has been examined using the potentiometric assay and the cell's ability to accumulate inorganic carbon in the presence and absence of sodium explored by silicon oil centrifugation techniques and the kinetics of photosynthesis.; The effects of NaCl and {dollar}rm Nasb2Osb4{dollar} on the external CA activity were studied.; The capacity of ten strains of P. tricornutum to take up bicarbonate has been examined by comparing the rate of photosynthetic O{dollar}sb2{dollar} evolution with the photosynthetic rate which could be supported solely by CO{dollar}sb2{dollar} arising from the uncatalyzed dehydration of HCO{dollar}sb3sp-.{dollar}; Sodium stimulation of bicarbonate transport has been examined in these 10 strains of P. tricornutum. (Abstract shortened by UMI.)...