Symbiosis in Marine and 

 Fresh Water Coelenterates 



Leonard Muscatine 



Laboratories of Biochcmistrij, Howard Hughes Medical Instittttc, Miami, Florida 



In studying the significance of symbiotic algae for the nutrition 

 and growth of their invertebrate hosts, we have been guided by two 

 objectives : a ) to estabhsh the existence of a nutritional relationship 

 between algae and host, and b) to characterize the chemical basis 

 of this relationship. 



Direct evidence for the contribution of carbon compounds from 

 symbiotic algae to the tissues of the host has been demonstrated 

 in a sea anemone ( 9 ) , a coral ( 3 ) , and in green hydra ( 5 ) . 



In this paper, we demonstrate a direct relationship between algal 

 symbionts and changes in mass or growth of a marine and a fresh- 

 water coelenterate. Our data show that retarded weight loss, en- 

 hanced growth, and prolonged survival of the animals studied could 

 be attributed to the presence of symbiotic algae. 



STUDIES ON SEA ANEMONES' - 



Experiments demonstrating retardation of weight loss were con- 

 ducted on Anthopleura elegantissima (Brandt, 1835), an intertidal 

 anemone which contains zooxanthellae within its gastrodermal cells 

 (Fig. 1). Specimens without algae, found beneath fish canneries 



^Part of a tliesis submitted in partial fulfillment of the requirements for the degree 

 of doctor of Philosophy, Department of Zoology, University of California, Berkeley. 



-This investigation was supported by a fellowship (EF-9653) from the National Insti- 

 tutes of Allergy and Infectious Diseases, Public Health Service. 



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