EFFECTS ON BACTERIA, FUNGI, YEASTS, AND VIRUSES 755 



accompanying tabulation), and these data show that (1) arsenicals are 

 as potent as HgClg against certain bacteria, (2) E. coli and P. vulgaris 

 are fairly resistant to the arsenicals, but not to HgClg, confirming earlier 



observations, and (3) the pentavalent arsenicals are not active. Inhibition 

 would certainly be expected in bacteria utilizing the cycle and obtaining 

 energy and synthetic units from pyruvate and related compounds, but 

 again the matter of penetration must be considered. It is very interesting 

 that 3 TCiM arsenite does not alter the growth of Aerohacter aerogenes, either 

 aerobically or anaerobically, but still causes the accumulation of pyruvate 

 (anaerobically from 24 to 360) and certain amino acids (Fowler and Werk- 

 man, 1955). Arsenite injected into mice at 5.4 mg/kg increases somewhat 

 the mortality of animals infected with various bacteria (Berry and Mitchell, 

 1953 c; Berry et al., 1954 a), and infection with Salmonella produces rises 

 in tissue citrate similar to those seen in arsenite-treated animals (Berry 

 et al., 1954 b). Thus the cycle was assumed to play a role in the suscepti- 

 bility of the host, and the elevated mortality perhaps to be due to summated 

 cycle blocking, although the effects of arsenite were rather minimal, espe- 

 cially compared to malonate. 



Yeasts and Fungi 



The early studies indicated the relative resistance of yeast to arsenite, 

 10 m.M inhibiting growth moderately, but complete inhibition occurring 

 only at 20 vaM (Johannsohn, 1874). A stimulation of growth at lower 

 concentrations was often noted (Diemair and Schlilke, 1941). There is 

 some evidence that the penetration of arsenicals into yeast does not readily 

 occur, although reaction with the surface leads to a change in the isoelec- 

 tric point of the cells (Janke and Garzuly-Janke, 1936). The growth and 

 sporulation of yeast are inhibited equally by arsenite (Miller and Halpern, 

 1956). Arsenite at 1 mM fairly well inhibits the growth of some species 

 of Candida and Torula, but Tory la utilis is resistant (Nickerson and Van 

 Rij, 1949). Pyruvate oxidation in Penicillium chrysogenum is inhibited 



