2i6 BACTERIAL OXIDATIONS AND REDUCTIONS 



interfere with the process of the reaction. A great deal of investigation on this type 

 of oxidation has been done by Quastel' and others, and has already been referred to 

 when discussing the reduction of methylene blue. The actual point chiefly studied is 

 the extent to which various fatty acids, amino acids, and other substances are capable 

 of being induced by bacteria to transfer H to methylene blue, i.e., the capacity of 

 these substances for oxidation by various bacteria. It is this type of oxidation which is 

 apparently responsible for furnishing the energy required by anaerobes or by faculta- 

 tive anaerobes growing in the absence of oxygen by fermentative processes. 



Braun and Cahn-Bronner^ have drawn attention to the more complex nutriment 

 required by bacteria growing under anaerobic conditions. 



A second type of oxidation is that in which oxygen is used freely and the fatty acids 

 which have been present in the medium at the outset, derived from amino acids by 

 deamination or from sugars by fermentative reactions, are oxidized to carbonates. 

 Ayers and Rupp^ first drew attention to the fact that such oxidations are associated 

 with the development of an alkaline reaction, and changes of this kind occurring in 

 diphtheria cultures have been the subject of very careful study by Abt and Loiseau^ 

 and by Abt.^ The production of alkali by oxidative formation of carbonates has been 

 noted in cultures of many varieties of bacteria by Sierakowski,^ and Phelon, Duthie, 

 and McLeod^ have drawn attention to its importance in cultures of gonococci and 

 meningococci in which it may be responsible for the rapid death of the bacteria. A 

 third distinctive type of oxidation is that of the types of bacteria described by Wino- 

 gradsky^ as "anorgoxydanten" and by Orla-Jensen' as "autotrophic." These get the 

 energy which they require for the assimilation of the atmospheric CO. by oxidation of 

 simple elements like S, H, and Fe or compounds such as nitrites, CH^, or NH3, and 

 are incapable of utilizing complex organic substances for their nutrition. According 

 to Waksman and Starkey,'° only certain S-oxidizing bacteria and the nitrifying bac- 

 teria are strictly autotrophic in the sense of inability to utilize any complex organic 

 forms of nutritive matter. 



A fourth type of oxidative effect produced by bacteria is that due to the produc- 

 tion of H2O2. The association between production of peroxide by bacteria and methe- 

 moglobin formation has been specially studied by Neill and Avery" in connection with 

 the pneumococcus, and by Valentine'- in connection with the streptococci. The former 

 have brought out the very interesting fact that anaerobic extracts of pneumococci 



' Quastel, J. H., et al.: loc. cit. 



= Braun, H., and Cahn- Bronner, C. E.: Centralbl.f. Bakteriol., Abt. I, Orig., 86, i. 1921. 

 3 Ayers, S. H., and Riipp, P.: J. Inject. Dis., 23, 18S. 1918. 

 * Abt, G., and Loiseau, G.: Ann. Inst, de Pasteur, 39, 114. 1925. 

 s Abt, G.: ibid., p. 387. 1925. 



^ Sierakowski, S.: Compt. rend. Soc. de biol., 89, 1371. 1923; Biochein. Ztschr., 151, 15. 1924. 

 ^ Phelon, H. V., Duthie, G. M., and McLeod, J. W.: /. Path, and Bait., 30, 133. 1927. 

 HVinogradsky, S.: Centralbl.f. Balderiol., Abt. II, Orig., 57, 1. 1922-23. 

 9 Orla- Jensen, S.: //;/(/., 27, 305. 1909. 



'"Waksman, S. A., and .Starkey, R. L.: J. General Physiol., 5, 285. 1923. Sec chap, xxiv in 

 this volume. 



" Neill, J. M., and Avery, O. T.: J. Exper. Med., 39, 757. 1924. 

 " Valentine, E.: J. Infect. Dis., 39, 29. 1926. 



