THE GONYAULAX CLOCK' 



J. WOODLAND HASTINGS 



Division of Biochemistry, Noyes Laboratory of Chemistry, 



University of Illinois, Urbana, Illinois 



BEATRICE M. SWEENEY 

 Division of Marine Biology, Scripps Institution of Oceanography, 



La JoUa, California 



Gonyaulax polyedra is an armored marine dinoflagellate that is both 

 photosynthetic and luminescent. It is one of several unicellular forms 

 that are responsible for the brilliant displays of luminescence seen in 

 the ocean at night when the water is disturbed. Luminescence in dino- 

 flagellates is considered in detail in Harvey's (1952) monograph. The 

 organism was isolated from a net sample taken off Scripps Pier in La 

 Jolla and has been grown in a supplemented sea water medium (Haxo 

 and Sweeney, 1955; Sweeney and Hastings, 1957a). It has retained its 

 brilliant blue luminosity in culture for more than five years. The wave- 

 length of maximum emission is about 475 ni/^ (Hastings and Sweeney, 

 1957a). 



The studies of Zacharias ( 1 905 ) , Moore ( 1 909 ) , Kofoid and Swezy 

 (1921), and Harvey (1952) indicated that the bioluminescence of 

 sea water containing dinoflagellates exhibited diurnal rhythmicity. 

 Moreover, a rhythm of cell division in the dinoflagellate Ceratiiim had 

 been demonstrated by the studies of Gough (1905), and Jorgensen 

 (1911). A similar rhythm of cell division in cultures of Peridiniiim 

 triquetmm was reported by Braarud and Pappas (1951). These ob- 

 servations suggested that Gonyaulax might be expected to have a 

 diurnal rhythmicity. 



Our studies have demonstrated the existence of a persistent endoge- 

 nous diurnal rhythmicity, i.e., a "clock" system, in Gonyaulax, and this 

 paper will serve to review its essential features. All our observations 



^ The previously unpublished studies cited in this paper were supported in 

 part by a grant from the National Science Foundation. 



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