FIG. 7.

Increase in 6-N-dimethylallyl-2-methylthioadenosine in strain CL100 with extended growth. The top trace is for tRNA isolated at late log phase, while the bottom trace is after extended incubation. There was an additional relative decrease in the amount of 6-N-dimethylallyl adenosine (i⁶A), which is the precursor to 6-N-dimethylallyl-2-methylthioadenosine. Parent strain MC1061 or CL100(DE3) with pCL010 showed only 6-N-dimethylallyl-2-methylthioadenosine at all growth levels examined (see Fig. 5 for comparison and for abbreviations).