Sussman R R
J Bacteriol. 1974 Apr;118(1):312-3. doi: 10.1128/jb.118.1.312-313.1974.
The growth response to external cyclic adenosine 3',5'-monophosphate of a strain of Escherichia coli deleted for adenyl cyclase was utilized to screen for mutants of Dictyostelium discoideum unable to accumulate this chemical extracellularly. The threshold amount of cyclic adenosine 3',5'-monophosphate able to induce growth of this bacterium was 3 to 4 mug/ml at 37 C and approximately 25 mug/ml at 27 C. Conditions are described that permit the detection of as low as 2 mug of this chemical at either temperature.