208 LIGHT AND LIFE 



limitations of space prevent a detailed discussion of his contributions 

 here. Further information and references to the literature in general 

 can be conveniently found in his several books (21, 26, 27, 29). 

 With particular reference to the luciferin-luciferase reaction, how- 

 ever, certain facts should be noted, as follows. 



The Known Examples 



Harvey made exhaustive tests for a luciferin-luciferase reaction 

 in extracts from virtually every type of luminescent organism he 

 could obtain. To the list of two examples found by DuBois, he 

 added the American {Photiniis and Photuris) and Japanese (Luciola) 

 fireflies (18, 20) , the ostracod Crustacea Cypridina (19) and Pyrocypris 

 (22), the marine fireworm Odontosyllis (25), and the deep sea 

 decapod shrimp Systellaspis (25) . Apart from a few falsely positive 

 results in the early studies, a luciferin-luciferase reaction could not 

 be demonstrated in any of various other groups of luminous or- 

 ganisms, including bacteria, fungi, sponges, radiolaria, flagellates, 

 medusae, pennatulids, ctenophores, ophiuroids, tomopterids, chae- 

 topterids, terebellids, polynoeids, earthworms, schizopods, myriapods, 

 cephalopods, ascidians, balanoglossids, or fish (26) . 



The list of examples of definitely positive reactions among different 

 types of organisms was not extended until 1950, when Bowden (5) 

 succeeded in demonstrating the luciferin-luciferase reaction in ex- 

 tracts of a fresh-water limpet, Latin. At the moment, the only addi- 

 tional examples are the luminous bacteria Acltromohacter and Photo- 

 bacterium (38, 39, 43, 44, 46), a dinoflagellate, Gouyaulax (31), two 

 kinds of fish, Parapriacanthus (15) and Apogon (16), the luminous 

 fungi Collybia and ArmiUaria (1), the sea pansy Renilla (7), and 

 a second decapod shrimp, Heterocarpus (13). It is noteworthy that 

 most of the established examples of a luciferin-luciferase reaction 

 have been discovered by Harvey and his students, his students' stu- 

 dents, or collaborators within this group, the only exceptions being 

 the examples found by Dubois (9, 10) and Bowden (5) , respectively. 



Despite the many failures to demonstrate a luciferin-luciferase re- 

 action in crude extracts of various organisms, there is little reason 

 to doubt that such a system is involved in light emission in essentially 

 all instances of bioluminescence. The failures can result from various 

 possible causes, some of which are indicated in paragraphs that fol- 

 low. Obvious iK)ssil)ilities for faihucs with (rude extracts include 

 dilution of reaclants, which may be normally held together in 

 granules of some sort, or the presence of inhibitors, which seems to 



