PMID:4933690

Citation	Wilson, TH, Kusch, M and Kashket, ER (1970) A mutant in Escherichia coli energy-uncoupled for lactose transport: a defect in the lactose-operon.Biochem. Biophys. Res. Commun. 40:1409-14
Abstract	No abstract in PubMed
Links	PubMed
Keywords	Biological Transport, Active; Carbon Isotopes; Cell Membrane; Coliphages; Escherichia coli; Galactose; Glycosides; Lactose; Molecular Biology; Mutation; Nitrobenzenes; Operon; Transduction, Genetic
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Main Points of the Paper

• Isolation of mutant (X71-54) with a severe defect in TMG accumulation
  • possesses elevated membrane carrier activity, therefore the rate of efflux is increased

Materials and Methods Used

• Parent Strain: X71 (i^-z⁺y⁺a^-, proC^-, try^-, B₁^-, F^-)
• Additional Strain: X71-54
• Additional Strain: Ca77 (lactose-deleted, B₁^-, Hfr)

• β-galactosidase assay
• ONPG uptake assay
• Thiomethylgalactoside (TMG) transport assay
• P₁ Transduction

Phenotype Annotations

Species	Taxon ID	Strain	Gene (if known)	OMP	Phenotype	Details	Evidence	Notes
Escherichia coli	NCBI:83333	X71-54	lacYUN	Decreased ability to maintain concentration gradient? Abolished energy-coupling transporter activity? Absent intracellular accumulation of thiomethylgalactoside (direct observation)	Other	Intracellular [14C]TMG accumulation	Other	Figure 1- Filter assay
Escherichia coli	NCBI:83333	X71-54	lacYUN	Decreased intracellular accumulation of substance Increased rate of transporter efflux? Decreased energy-coupled transport? Increased rate of efflux of thiomethylgalactoside (TMG) (direct observation)	Other	exit rate of [14C]TMG was faster than that found for the parent	Other	Figure 2- Filter assay
Escherichia coli	NCBI:83333	X71-54	lacYUN	Increased rate of transporter substrate uptake? Increased transport of small molecules Increased rate of transporter activity	Metabolic Activity	130% of normal uptake activity (gauged by ONPG entry)	Biochemical Assay	Table 1- ONPG assay
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Notes

Additional papers regarding this mutant can be found here