FIG 3.

Detection of guanidinium compounds by TLC. A. niger strains (the WT and D-42 strains) were grown in liquid culture with agmatine (A), GB (B), l-arginine (C), and NH₄NO₃ (D) as the sole nitrogen source. Aliquots of these culture media (2.0 μl each) were spotted on TLC plates, developed in solvent system I, and visualized by use of the Sakaguchi reagent. Results for samples obtained after every 10 h of growth (lanes 1 to 10) are shown. Culture media with no nitrogen (lane M), the standards (l-arginine, ornithine, agmatine, putrescine, GB, GABA, urea, citrulline, SSA, and GBald [lanes 1 to 10, respectively]), and a mixture of l-arginine, agmatine, and GB (lane 11) were tested.