Mutants ofSerratia marcescenslacking cyclic nucleotide phosphodiesterase activity and requiring cyclic 3′,5′-AMP for the utilization of various carbohydrates
✍ Scribed by U. Winkler; H. Scholle; L. Bohne
- Publisher
- Springer
- Year
- 1975
- Tongue
- English
- Weight
- 866 KB
- Volume
- 104
- Category
- Article
- ISSN
- 0302-8933
No coin nor oath required. For personal study only.
✦ Synopsis
Adenine requiring mutants of Serratia marcescens SM-6-F'lac + have been found to grow well in minimalglucose medium solely supplemented with cAMP. From one of these ade strains double mutants (called ade cpd) were isolated which could no longer utilize cAMP but which still grew on 5'AMP. Dialyzed cell extracts (soluble fraction) of the double mutants, assayed for cAMP phosphodiesterase, were unable to hydrolyze cAMP whereas cell extracts of the parental strains yielded 5'AMP at a rate of 1.6--2.0 Izmoles rain-1 mg -~ protein. The loss of the phosphodiesterase activity in S. marcescens cpd W 1181 did not cause an accumulation of large amounts of cAMP as was found for the diesterase-negative mutant AB 257p e-~ of Escherichia coil The induced synthesis of fl-galactosidase in mutant cpd Wl181 showed about the same sensitivity to transient and permanent catabolite (glucose) repression as the corresponding cpd + strain.
Starting from S. marcescens cpd Wl181 three independent double mutants (called cpd cya) were isolated which required exogenous cAMP for utilizing various carbohydrates as carbon source, for motility and for the formation of extracellular lipase and the red pigment prodigiosine. The intracellular concentration of cAMP in these mutants, grown in nutrient broth, was 40-60 ~o of that of the parental strain which is about 4 • 10 -4 M. However, the adenylate cyclase in cell extracts of the mutants W1237 and W1270 was like that of the corresponding cya + strain (about 2x 10 -~ ~moles rain -1 mg -1 protein).