Control of Bacterial Cell Growth and Composition 337 



enough, the rate of glucose oxidation by glycerol-grown cells 

 was not enhanced by Mg^+. The effect of Mg^+ on the glucose 

 metabolism of glucose-grown cells consists in the stimulation 



Table I 



Rates of oxidation of glucose and of its degradation products 

 IN Aerobacter aerogenes 



The rates are expressed as yd. of Oo taken up in one hour by one unit of cells in 

 phosphate buffer at pH 6-4 and 37° (Magasanik, Brooke and Karibian, 1953). 



of the production of gluconate, pyruvate and a-ketoglutarate 

 from glucose, and of the production of carbon dioxide from 

 C-1 of glucose (Table II). It appears, therefore, that glucose 



Table II 



Glucose metabolism in Aerobacter aerogenes 

 Growth medium . . . Glucose Glycerol 



Additions . . . None Mg^ + None Mg^ + 



Glucose, (jimoles —1-8 —4-9 —1-5 —1-7 



Gluconate, [j,moles +0-8 +3-5 — — 



Ketoglutarate, [Jimoles +0-4 +0-6 +0-2 +0-2 



Pyruvate, [xmoles +0-07 +0-4 +0-03 +0-02 



CO2, (Jimoles +2-2 +2-8 — — 



O2, [^moles -2-7 -4-9 -31 -3-7 



i*C02/[l-i4C]glucose 0-15 0-36 0-13 15 



The experiments were carried out in Warburg vessels at 37° in phosphate 

 buffer, pH 6-4, which contained Mg2+ at a concentration of 8 x 10"* m where 

 indicated. The last line of the Table presents the ratio of the radioactivity 

 values of the isolated COg and of the [l--^*C]glucose used as substrate. 



induces the formation of an enzyme(s) which requires a high 

 level of Mg2+ and which permits the rapid degradation of 

 glucose via gluconate, or presumably, phosphogluconic acid; 

 at the same time glucose suppresses the formation of enzymes 



