UPTAKE AND ASSIMILATION OF AMINO ACIDS BY PLATYMONAS

Abstract

The marine flagellate Platymonas subcordiformis rapidly accumulates amino acids at concentrations likely to be found in nature. Accumulated C14 amino acids are assimilated into alcohol-insoluble compounds and enter oxidative pathways. Relation between uptake velocity and substrate concentration was determined, and maximum uptake velocity estimated. At an ambient glycine concentration of 1.0 [mu]mole/1, the uptake mechanism can provide at least 10% of cell nitrogen requirement. This provides further evidence for normal heterotrophic activity in phytoplankters.