Fig. 4. Behavioral analysis of the bas mutants. (A) CIP assay of the wild-type (a), ΔΔ (b), Ω (c), basT_trunc (d), ΔbasT (e) and ΔbasB (f) strains. Chemotactic depletion rings are indicated (white arrows). Hard agar plugs filled with arginine (Arg) or with chemotaxis buffer alone (CB) served as positive and negative controls, respectively. (B) Amino acid-induced (5 mM, arrows) changes in the rate of [³H]methyl group release of the H.salinarum strains wild type (closed circles) and basT_trunc (open circles). Subsequent arginine stimulations at 5 mM served as a control.