
CURRENT LITERATURE 
NOTES FOR STUDENTS 
Metabolism of fungii—Among recent papers on the metabolism of fungi 
two’ on protein synthesis are of special interest. The first by EHR1LIcH' relates 
to the utilization of the nitrogen of amino acids when substances other than 
sugar form the source of energy. In his former work EHRLICH showed that in 
the presence of sugar the a-amido acids are transformed by yeast into carbon 
ioe ammonia, and alcohols with one carbon atom fewer than the corre- 
ponding amino acids, the ammonia being used in protein synthesis, while the 
ei residue is excreted as a waste product. In the present paper he reports 
the results of an investigation of the action of yeasts on an amino acid, tyrosin, 
when simpler compounds such as alcohol, glycerine, lactic acid, etc., are supplied 
as sources of carbon. He finds that the decomposition of the amino acid 
proceeds in the same manner regardless of the source of carbon, and that even 
with these less favorable sources of energy the nitrogenous radical only of the 
amino acid is utilized by the organism. In cultures containing cane sugar, 
glycerine, or alcohol in addition to tyrosin, small quantities of esters and volatile 
fatty acids were formed. Oidiwm lactis was found to behave in an analogous 
manner. EHRLICH and JACopsoN had shown that in the presence of sugar this 
fungus produces from amino acids the corresponding oxyacids. Its behavior 
in this respect was not changed when glycerine, lactic acid, or alcohol were used 
instead of sugar. With each of these substances tyrosin yielded paraoxy- 
phenyl lactic acid, only the nitrogenous portion of the molecule being utilized 
by the fungus 
WITSCH? approached the problem of protein synthesis from another 
point of view, by determining the energy required, as measured by the carbon 
dioxide output per unit of dry weight of fungus, for the assimilation of different 
nitrogenous compounds by Aspergillus niger. Of the large number of nitro- 
genous compounds tested with sugar, low ratios of carbon dioxide to oe 
weight were obtained with methyl urea, the amino acids, potassium sulpho- 
cyanate, acetamide methyl amine, and urea, while such compounds as guanidin, — me 
ethylamine, potassium nitrate, peptone, protein, and phenyl urea gave higher 
ratios, showing that more energy is required for their assimilation. Fewer 
nitrogenous compounds were tried in connection with succinic acid, malic acid, 




 EBRLI .. Uber die Bildung des Plasmaeiweisses bei Hefen und Schimmel 
‘liven. Spr Zeltache, 36:477-497. IQII. : 
? Purtewrtscn, K., Untersuchungen tiber die Eiweisssynthese bei niederen 
Pflanzen. Biochem. Zeltachs. 38: 1-13. 1912, v : 
504 





