216 Papers from the Department of Marine Biology. 



OXIDASE AND CATALASE. 



Many enzymes are found in bacteria in a condition which defies 

 extraction except by means of the Biichner press, and it is difficult to 

 obtain luminous bacteria in sufficient quantity for this method. The 

 oxidases seem to be contained in these bacteria in this endoenzyme 

 condition. All my efforts to obtain an oxidase in solution which will 

 oxidize the common oxidase reagents guaiac, a-napthol, para-pheny- 

 len diamine, phenolphthalin, and pyrogallol have failed, even though 

 hydrogen peroxide is added. 



Similar results have been obtained by other workers. Gessard (29) 

 showed that a melanogenic variety of Bacterium pyocyaneum would 

 turn tyrosin brown, but he was unable to separate a solution of 

 tyrosinase from the bacteria. Lehmann and Sano (so) found also 

 that Actinomyces chromogenes, Bacterium putidum, and B. phosphor- 

 escens would oxidize tyrosin in the culture medium, but Vibrio indicus, 

 which phosphoresces strongly, Sarcina lutea, B. typhi, B. coli, and many 

 others would not. They found in addition that a substance oxidizing 

 aloin and giving a very weak guaiac reaction could be extracted from 

 Actinomyces chromogenes, B. putidum, and B. phosphorescens by a mix- 

 ture of two parts glycerine to one of water, but no tyrosinase reaction 

 could be obtained with this extract. Here also the tyrosinase is appar- 

 ently in an endoenzyme condition. 



As we shall see (p. 225) the vegetable oxidases are capable of oxidiz- 

 ing pyrogallol with light-production, but many attempts to produce 

 light with pyrogallol and extracts of luminous bacteria failed. 



Catalase also occurs in the luminous bacteria with which I worked, 

 but in small amount. 



LUMINOUS BACTERIA AND OSMOTIC PRESSURE. 



Most marine animals require an external medium of some definite 

 osmotic pressure, and they will not live below this limit; some marine 

 forms (Fundulus) are independent of an external osmotic pressure. 

 Luminous bacteria belong to the first category, as indicated in table 15. 

 They will not live in dilute sea-water, but they will live in it if its 

 osmotic pressure is raised by some inert substance like isotonic cane- 

 sugar. Note also that some salt is necessary for the continued pro- 

 duction of light, as the bacteria no longer glow after 24 hours' immer- 

 sion in m sugar, a fact of no great surprise, as unicellular fresh-water 

 luminous animals are unknown. 



In these experiments, as well as those with the salts of sea-water, 

 acid and alkalies, and alcohols, one drop of a dense emulsion of lumi- 

 nous bacteria (a form isolated from squid at Woods Hole, Massachu- 

 setts) was added to 30 c.c. of solution in an uncorked Erlenmeyer flask 

 and the whole thoroughly mixed. For comparative observations it is 

 essential that the eye be thoroughly adapted to the dark and that each 



