[Investigations of amino acid metabolism by thin layer chromatography for differentiation of Brucella (author's transl)].

The amino acid metabolism of 23 different Brucella strains was investigated for differentiation purposes. The results were evaluated by thin layer chromatography, after enzymatic incubation. The organisms (Tab. 1) were grown on Tryptose blood agar at 37 degree C for 24 or 48h. Two mg wet weight of bacteria in 0.2 ml PBS, 0.01 M, were incubated with 12.5 microng (0.025 ml) amino acid in small tubes for 16h at 37 degree C, and centrifuged for 15 min at 7500 X g. For controls, bacterial suspensions were heated for 15 min at 100 degree C to destroy enzymatic activity, and also contrifuged for 15 min at 7500 X g. Usually 4 micronl of the supernatant fluids (6 micronl for L-asparagine, and 10 micronl for L-proline) were pipetted on the thin layer plate. The tests were run in n-butanol acetic acid water, 20:5:5, with a distance of 8 cm. Amino acids were stained with ninhydrine. The tests were repeated 3-5 times with identical results. Amino acid metabolism was indicated by different staining intesities (+ to ++) in comparison to control preparations. All species could be exactly differentiated from each other, with the exception of B. suis, biotype 2, and B canis, which could not be differentiated by their amino acid metabolism. Biotyps of the same species were mostly identical. The results of these investigations could be reproduced qualitatively as well as quantitatively. The method described is recommended for routine investigations.