244 



E. S. GUZMAN BARRON, F. GHIRETTI 



VOL. 12 (1953) 



TABLE VI 



INTERMEDIATES OF THE CITRIC ACID CYCLE FOUND IN THE CULTURE MEDIA OF 

 CERTAIN MOULDS GROWN IN ACETATE AS THE MAIN SOURCE OF OXIDIZABLE MATERIAL 



The figures give micrograms per ml of culture media, blank subtracted. 



* Determined as a-ketoglutarate 



Detected by paper chromatography, 



TABLE VII 



EFFECT OF MALONATE ON THE OXIDATION OF ACETATE BY MICRO-ORGANISMS 



Acetate, o.oiM; Malonate, o.oiM. Temp. 38°. Incubation time 90 minutes. All figures blank 



subtracted. 



Micro-organism 



PH 



O2 Uptake 



Control 

 c.mm. 



Malonate 

 c.mm. 



Fig. 4. Oxidation of malonic acid by Aerobacler cero- 

 genes. Buffer 0.03 M phosphate pH 7.0. Malonate 10 

 micromoles. Abscissa time in hours. Ordinate Oj up- 

 take in c.mm. Figures given are blank subtracted. 

 Temp. 37.5°. Calculated O^ uptake for complete oxida- 

 tion malonate 448 c.mm; found 179.7 c.mm (40% of 

 total oxidation). 



References p. 249. 



75%. Lynen, aware of the membrane 

 impermeability of yeast, obtained 

 malonate inhibition by disturbing the 

 membrane on treatment of yeast cells 

 with liquid nitrogen-^. At pH 5.54, the 

 lowest pH for respiration of these 

 microorganisms, acetate oxidation by 

 C. creatinovorans was inhibited "^jyo', 

 by Pseudomonas fluorescens, 15%; by 

 Tetrahymena geleii, completel}'. The 

 membrane of moulds seems more im- 

 permeable to malonate : malonate had 

 no effect at all on the o-xidation of 

 acetate by M. niveus or R. nigricans. 



Malonate was oxidized by Aero- 

 bacler aerogenes after an induction 

 time, which increased as the cell con- 

 centration decreased. Oxidation stop- 



