388 RESPIRATORY METABOLISM 



probably different from the anaerobic mechanism of the facultative an- 

 aerobes (Broh-Kahn and Mirsky, 1938). 



There is considerable evidence that carbohydrate decomposition takes 

 place in Protozoa under anaerobic conditions. It was found by Putter 

 (1905) that the glycogen content of Paramecium decreased under an- 

 aerobic conditions. He also found that Paramecium poor in glycogen 

 could live anaerobically for a considerable length of time, probably at 

 the expense of albumen. A. Lwoff (1932) found that Glaucoma piri- 

 formis could live three days without oxygen only if sugar were present. 

 M. Lwoff (1934) obtained a value of 10 for the Q^^ of G. piriformis in 

 peptone broth (Qoo = 35). Emerson (1929) found that under an- 

 aerobic conditions 80 mm^ of Blepharistna released 12.5 mm.^ CO2 per 

 hour from a bicarbonate buffer mixture; negative results were obtained 

 with Amoeba proteus. Zhinkin (1930) demonstrated that the glycogen 

 content of Stentor decreased under anaerobic conditions and that visible 

 fat increased. Upon exposure to Oo that fat disappeared. This apparent 

 conversion of glycogen to fat was observed in experimental cultures and 

 under natural conditions in winter when the O, content of ponds was 

 negligible, but it did not occur in experimental cultures in the presence 

 of light because of the photosynthetic action of zoochlorellae. Some data 

 of this type was also obtained for Prorodon teres and Loxodes (Zhinkin, 

 1930) and for Paramecium (Pacinotti, 1914). The possible changes 

 which take place in the glycogen content of intestinal amoebae and 

 ciliates should also be investigated in this connection (see discussion by 

 von Brand, 1934). 



The trypanosomes are a group of organisms which live under con- 

 ditions of high Oo tension, but they apparently have a high degree of 

 anaerobic metabolism (glycolysis). At least, they use much more sugar 

 than they could possibly oxidize with the Oo which they consume, and 

 apparently the amount of acid produced by glucose destruction does not 

 differ much under aerobic or anaerobic conditions. According to the data 

 of von Fenyvessy and Reiner (1924), the O2 consumption for a billion 

 trypanosomes (T. equiperdum) suspended in diluted blood was about 

 0.07 mg. per hour. The sugar consumed under similar conditions (Yorke, 

 Adams, and Murgatroyd, 1929) was about 5 mg. Since complete oxida- 

 tion of 5 mg. of sugar requires about 5 mg. of Oo, it appears as if the 

 major portion of the sugar destruction was anaerobic. This is discussed 



