EFFECTS OF MITOTIC GROWTH-FACTORS ON GROWTH-RATES IN MARINE DINOFLAGELLATES

The effects of different growth factors and mitogens (platelet-derived growth factor, phorbol 12 monoacetate and fetal bovine serum) on dinoflagellate proliferation were analysed in axenic clonal cultures of the bloom-forming dinoflagellates Prorocentrum triestinum Schiller and Alexandrium tamarense (Lebour) Balech. Cell yield and acclimatized maximal growth rates of all clones tested increased significantly due to the specific mitogenic effect of growth factors. This is thought to be due to the existence of a universal mechanism controlling the cell division cycle in all eukaryotic cells. Apparently dinoflagellates respond to growth factors in a similar way as mammalian and yeast cells. Because growth factors can increase growth rates, they could play a significant role in the occurrence and proliferation of dinoflagellate blooms.