Meeting Abstract
The cnidarian-dinoflagellate endosymbiosis relies on the cellular coordination of its two partners, algal symbionts and the host cnidarian cells that contain them. We examined the effect of nutritional status and symbiotic state on host cell proliferation in the sea anemone Aiptasia sp., and its resident algal symbionts Symbiodinium clade B1, a model system for coral-dinoflagellate symbiosis. Anemones under three different symbiotic conditions: symbiotic, aposymbiotic (without symbionts) and colonizing (aposymbiotic animals being re-colonized with algae) were treated and stained with S-phase marker 5-ethynyl-2′-deoxyuridine (EdU), late G2/M-phase marker phospho-histone H3 (Ser10), and Hoechst dye. In symbiotic anemones, host cell replication and division was lowest at night and peaked in the late afternoon. Symbiotic and aposymbiotic anemones had similar division rates, though starvation led to increased proliferation of primarily mucocytes. Starvation also had a positive effect on symbiont proliferation but not host cell division during onset of symbiosis. Our results suggest that changes in host cell cycle and proliferation are basic cellular responses to environmental flux and symbiont status.
