Ume symbiosis, where the host plant is known to control bacteroid differentiation by means of peptide signaling molecules (238, 382). Such a cross-systems approach will be invaluable as we attempt to understand the complexities and interrelationships of the host and symbiont cell cycles in the cnidarian-dinoflagellate symbiosis.METABOLIC EXCHANGE AND NUTRIENT TRAFFICKINGInorganic Carbon Acquisitio