PMID:4994599

Citation	Burman, LG and Nordström, K (1971) Colicin tolerance induced by ampicillin or mutation to ampicillin resistance in a strain of Escherichia coli K-12.J. Bacteriol. 106:1-13
Abstract	A mutant (G11el) of Escherichia coli selected as being resistant to ampicillin and showing signs of an envelope defect was also found to be tolerant to colicins E2 and E3. The colicin tolerance of G11el could be partially repressed by Mg(2+) ions. Transition from tolerance to sensitivity and vice versa by shifting the concentration of Mg(2+) in the growth medium required several generations. This indicated that synthesis of new envelope material was needed for transition. Previous physiological results have indicated a change in the envelope lipopolysaccharide (LPS) of G11el. However, chemical analyses revealed no differences in carbohydrate composition between LPS from G11el and its parent strain G11al. Genetic experiments showed that the mutation in G11el is located at about 20 min on the E. coli K-12 chromosome. The mutation was dominant over wild type in partial diploids with the mutation located on the episome. Because colicin tolerance was the most striking phenotypic effect as a result of mutation in the actual locus, this gene will be named tolD until the exact gene product is known. Spheroplasts formed from G11al and G11el by ethylenediaminetetraacetate-lysozyme treatment did not adsorb colicin E2; however, penicillin spheroplasts of G11al and G11el were tolerant to colicin E2. Thus, colicin tolerance can be induced biochemically. It is suggested that colicin tolerance often is a secondary consequence of a change in the cell envelope.
Links	PubMed
Keywords	Ampicillin; Cell Wall; Chromatography, Gas; Chromosome Mapping; Chromosomes, Bacterial; Colicins; Crosses, Genetic; Culture Media; Edetic Acid; Escherichia coli; Genes; Genetics, Microbial; Hexosamines; Lipopolysaccharides; Magnesium; Monosaccharides; Muramidase; Mutation; Penicillin Resistance; Phenotype; Phosphates; Polysaccharides, Bacterial; Protoplasts; Recombination, Genetic; Trypsin
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Phenotype Annotations

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Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: G11a1 NCBI Taxon ID: 83333	Genotype of Reference Strain: tolD+ Genotype of Experimental Strain : tolD mutation in strain G11e1	Reference Condition:			0000181	in vitro culture assay data	The tolD mutation confers significant tolerance toward colicins E2 and E3. See Figure 2 for the Colicin E2 killing kinetics data.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: G11a1 NCBI Taxon ID: 83333	Genotype of Reference Strain: tolD+ Genotype of Experimental Strain : tolD mutation in strain G11e1	Reference Condition:			0000033	traceable author statement	The tolD mutation confers sensitivity toward phage BF23.
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