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

Summary: Some 300 strains of bacteria representing twenty genera were grown on an acid-hydrolysed casein medium. Using the paper chromatographic technique of Woiwod (1949) a preliminary survey was made of the amino-acid and polypeptide composition of the bacterial culture filtrates. It was proved that: (a) changes may occur in the filtrate chromatogram which have group or species significance; (b) bacteria with simple nutrient requirements, i.e. which utilize ammonia, do not affect the chromatogram in the initial growth stage; (c) whenever the chromatogram is affected serine is the first amino-acid to be metabolized; (d) Gram-positive bacteria eliminate the aspartic acid spot but leave the basic amino-acid group unaffected, and the reverse occurs with Gram-negative bacteria; (e) many bacteria synthesize ninhydrin-positive material, presumably polypeptide, the synthesis of a given kind of polypep-tide being sometimes associated with a particular group or species of bacteria. By a disintegrator technique it was demonstrated that bacteria store many free amino-acids inside the cell.