The Examination, by Partition Paper Chromatography, of the Nitrogen Metabolism of Bacteria

Abstract

Some 300 strains of bacteria representing 20 genera were grown on an acid-hydrolyzed casein medium. Using the paper chromatographic technic of preceding paper, a preliminary survey was made of the amino acid and polypeptide composition of the bacterial culture filtrates. It was proved that changes may occur in the filtrate chromatogram which have group or species significance; bacteria with simple nutrient requirements, i.e., which utilize ammonia, do not affect the chromatogram in the initial growth stage; whenever the chromatogram is affected serine is the first amino acid to be metabolized; Gram-positive bacteria eliminate the aspartic acid spot but leave the basic amino acid group unaffected, and the reverse occurs with Gram-negative bacteria; and many bacteria synthesize ninhydrin-positive material, presumably polypeptide, the synthesis of a given kind of polypeptide being associated with a particular group or species of bacteria. By a disintegrator technic it was demonstrated that bacteria store many free amino acids inside the cell.