© 1969 by The Society for Integrative and Comparative Biology
Interference with Deposition of Minerals in a Coccolithophorid Protozoon
The Long Island Jeiuish Hospital and State University of New York Downstate Medical Center
Laboratory studies with axenic culture of the coccolithophorid, Hymenomonas MP 156, in chemically defined media have established that this primitive protist deposits its minerals in essentially the same manner as multicellular organisms. An appreciable number of inhibitors and natural compounds prevent deposition of minerals in laboratory experiments. Among these cations other than Ca+2, certain amino acids, select intermediates of carbohydrate metabolism, and inhibitors of enzymes occupy a prominent place. Interference with deposition of minerals does not necessarily abolish proliferation of the coccolithophorid. However, electron-microscopic, autoradiographic, histological, and analytical studies of the various modes of interference reveal a profound alteration of organelles and physiological activities. The ability of the protist to use its own extracellular, mineralized, calcareous structures as a source of Ca+2 for growth under conditions of reduced cations in the environment suggests a possible role for these microorganisms in cation equilibria of natural waters.