title: Xylitol and D-arabitol toxicities due to derepressed fructose, galactitol, and sorbitol phosphotransferases of Escherichia coli.
abstract: d-Arabitol was observed to be toxic to many laboratory strains of Escherichia coli K-12, and xylitol was found to be toxic to an existing E. coli C mutant strain. Fructose-specific components of the phosphoenolpyruvate:sugar phosphotransferase system are required for xylitol toxicity. Selection for xylitol resistance results in Fru(-) strains blocked in fructose phosphotransferase. Introduction of the ptsF or ptsI mutation into a xylitol-sensitive strain eliminates sensitivity. [(14)C]fructose uptake experiments imply that the mutation to xylitol sensitivity, which is co-transducible with ara and leu, results in derepression of normally inducible fructose phosphotransferase. Wild-type strains also become xylitol sensitive if induced by (and then removed from) fructose. Xylitol toxicity is prevented by fructose in both wild-type and mutant strains. Circumstances causing xylitol, a new food additive, to become toxic to an otherwise insensitive wild-type organism have not been reported previously. The d-arabitol-sensitive laboratory strains are galactitol (dulcitol) utilizers, although most other strains are not. Selection for d-arabitol resistance results in Gat(-) strains blocked in a constitutive galactitol-specific component of the phosphotransferase system. A mutation causing d-arabitol sensitivity occurred many years ago in AB284, the parent of AB311, AB312, AB313, and many other strains. d-Arabitol sensitivity also occurs in sorbitol-constitutive strains and is shown, like the previous two instances of pentitol toxicities, to result from a constitutive phosphotransferase, which is blocked in mutants selected for resistance.
mesh_terms: D001089:Arabinose; D004794:Enzyme Repression; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D005632:Fructose / Q000378:metabolism; D004376:Galactitol / Q000378:metabolism; D005796:Genes; D009154:Mutation; D010641:Phenotype; D010770:Phosphotransferases / Q000096:biosynthesis* / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism; D013402:Sugar Alcohols / Q000494:pharmacology*; D014993:Xylitol / Q000494:pharmacology*
chemical_list: D013402:Sugar Alcohols; D004376:Galactitol; D005632:Fructose; D013012:Sorbitol; D001089:Arabinose; D010770:Phosphotransferases; D014993:Xylitol; C014999:arabitol