SO ENZYMES AND ENZYMIC ACTIVITIES OF FUNGI 



in a test tube containing a sample of the stomach contents, this 

 fungus possesses the ability to transform metallic arsenic into tri- 

 methylarsine, which can be detected by its pungent odor, remi- 

 niscent of garlic. 



The enzymic activity of fungi is involved in the production of 

 a variety of products, including alcohol, organic acids, pigments, 

 fats, and carbohydrates, as is explained in Chapter 4. From the 

 discussion in that chapter some appreciation can be gained of the 

 influence of food supply, temperature, reaction, and O^ tension 

 on the enzyme-producing abilities of fungi. 



Certain cosmopolitan molds, such as Aspergilhts niger, Penicil- 

 Ynmi glaucinn, and Khizopns nigricans, are omnivorous by virtue 

 of their ability to produce a large number of enzymes, represent- 

 ing each of the groups: carbohydrases, proteases, lipases, oxidases, 

 and reductases. 



Humus formation is associated with enzymic activities, as is evi- 

 denced in striking manner by the decomposition of litter on the 

 forest floor. Many species of soil-inhabiting molds are capable 

 of transforming the cellulose and lignin portions that are rather 

 resistant to decomposition. The activities of a few of them, not- 

 ably species of Trichoderma, Chaetomium, and Aspergillus, have 

 been studied in considerable detail. A comprehensive idea of 

 these activities and of their importance in the economy of nature 

 is summarized in The Microbiology of Cellulose, Heviicelluloses, 

 Pectins, and Gums by Thaysen and Bunker (1927). 



General considerations. Although much has been learned 

 about the ability of enzymes from fungi to effect analyses and 

 svntheses, further knowledge of these matters should be sought. 

 Problems of host-parasite relationship, of host specificity, of the 

 synthesis of vitamins by fungi, and of antagonistic and synergetic 

 relationships among species may all be elucidated when more is 

 known about enzymes. The phenomenon of autodigestion among 

 fungi invites further consideration. Pleomorphism, especially the 

 tendency of species that are mycelioid in their natural habitat to 

 become yeast-like on artificial media, or vice versa, may be cor- 

 related with enzymic activity. Until techniques have been per- 

 fected to the extent that it is possible to measure the activity of 

 small groups of fungus cells or even of single cells and a body of 

 pertinent data has been amassed, material progress with studies 

 of this kind may be impossible. 



