1915] 



DAVIS ENZYME ACTION IN MARINE ALGAE 829 



Viva in sewage-contaminated waters. In order to break down 

 the proteins present in the surrounding waters and even those 

 in close contact with the plant itself, it would be necessary for 

 the Viva to secrete an extracellular enzyme, since the large 

 protein molecule is not diffusible into the cell. If so secreted, 

 the enzyme would be quickly dissipated in the large volume 

 of surrounding water. Desamidizing bacteria, on the other 

 hand, have been demonstrated in harbor and shore waters 

 where such algae abound. They can come into much more 

 intimate contact with the protein than can the plant, and un- 

 doubtedly play an important role in rendering available at all 

 times an abundant supply of organic nitrogen. 



The demonstration of nucleases acting upon the previously 

 split nuclein molecule, substantiates the findings of Teodoresco 

 for this enzyme. Both Viva and Ceramium showed the 

 presence of the ferment, while Ascophyllum, the only repre- 

 sentative of the " browns'* investigated, gave negative re- 

 sults. Where such enzymes were formed, they compared more 

 favorably with enzymes of fungi and higher plants than do 

 any of the other algal ferments. 



None of the "browns" studied showed the presence of 

 oxidative enzymes, while in the ' ' reds ' ' and the ' ' greens ' ' but 

 one form gave the characteristic reactions. It is interesting 

 to note that these algae, Agardhiella and Viva, were the most 

 enzymatically active forms studied. The oxidase reactions 

 with guaiacum, alpha naphthol, and phenylphthalin were very 

 positive, both directly, and indirectly with hydrogen peroxide. 



In all cases where enzymes were demonstrated, the action 

 was very slow, being with the exception of nuclease, much less 

 rapid than in the higher plants. The reason for this is not 

 clear, but it cannot in all instances be due to inhibiting sub- 

 stances set free upon the death of the cell. Arber ('01), as 

 has been mentioned before, found that Viva, Cladophora, and 

 Enteromorpha, placed in the dark but under otherwise pre- 

 sumably normal conditions, required from two weeks with 

 Viva, to two months and more in the case of Enteromorpha 

 for destarching. This indicates the presence of a very slowly 

 acting diastase in the cells of these algae. The metabolism 



