Monterey Bay Aquarium Research Institute
Seminars
Virginia Weis, Ph.D.

Oregon State University, Department of Zoology

The regulation of cnidarian-dinoflagellate mutualisms:
In sickness and in health

Wednesday — February 27, 2013
Pacific Forum — 3:00 p.m.

Cnidarians such as reef-building corals engage in a mutualistic symbiosis with intracellular photosynthetic dinoflagellates. This intimate partnership forms the trophic and structural foundation of coral reef ecosystems. This presentation will examine the cellular and molecular mechanisms underlying the establishment, maintenance and breakdown of the symbiosis in coral- and anemone-dinoflagellate partnerships. Host innate immunity and symbiont strategies for modulating this immune response are central to the stability of the symbiosis. During onset and maintenance of symbiosis these mechanisms include, lectinglycan signaling, upregulation of the immunosuppressive TGFβ pathway and changes in the sphinolipid rheostat. Coral bleaching, a severe threat to the health of reefs worldwide, is caused by global warming and results from the dysfunction and collapse of the symbiosis. Several studies suggest that coral bleaching is a host innate immune response to a symbiont compromised by severe oxidative stress. This evidence includes increased nitric oxide levels, and host cell apoptosis and autophagy in heat-stressed animals, all well known immune mechanisms in other systems to eliminate detrimental microbial invaders.

 

Next: March 6—David Helvarg