A new type of Escherichia coli K12 phoB mutant was isolated as 5-fluorouracil-plus-adenosine-resistant derivatives of a upp phoS,T strain. Such phoB mutants (called type III) differ from previously described phoB mutants (types I and II) in the synthesis pattern of phosphate-regulated periplasmic pr
The isolation and characterization of glutamine-requiring strains of Escherichia coli K12
β Scribed by Mayer, Eugene P. ;Smith, Oliver H. ;Fredricks, Walter W. ;McKinney, Michael A.
- Publisher
- Springer
- Year
- 1975
- Tongue
- English
- Weight
- 761 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0026-8925
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β¦ Synopsis
Mutants of Escherichia coli K12 requiring glutamine as a nitrogen source were isolated, and characterized as lacking glutamine synthetase activity. Temperature sensitive revertants of one of the mutants had a heat labile glutamine synthetase, while temperature insensitive revertants had a glutamine synthetase which was thermostable in vitro, indicating that the mutation was in the structural gene for the enzyme. All of the mutations mapped in the same region of the chromosome suggesting that they might all be in the same gene. The glutamine synthetase gene (gln) was located on the E. coli chromosome by conjugation and P1-mediated transduction at minute 77. The gln gene cotransduced with the genes for oleate degradation (old), and the genes for L-rhamnose utilization (rha). The most probable gene order is old-gln-rha.
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