D galactose

Compound 4 was purchased from ChemDiv (San Diego, CA, USA). The NanoGlo Luciferase Assay Substrate was purchased from Promega (Madison, WI, USA), Polymyxin B nonapeptide (PMBN), dimethyl sulfoxide (DMSO), bovine serum albumin (BSA), Tween-20, phosphate-buffered saline (PBS) were purchased from Sigma-Aldrich (St. Louis, MO, USA). D(+)-glucose, D(+)-galactose, D(+)-raffinose, yeast nitrogen base without amino acids, Bacto peptone, Bacto yeast extract and the different amino acid complements were purchased from Formedium™ (Swaffham, Norfolk, England).

Selection of URA3⁺ strains was performed on SD–Adenine–Uracil plates. Following verification of strains (see above), cells were grown in SD–Adenine (to maintain selection of the pASZ11:NupNop plasmid) for all experiments. SD–Adenine (pH 5.8) was formulated as follows (quantities of components per L are indicated): Yeast nitrogen base without amino acids (Formedium, Hunstanton, UK), 6.7 g; D(+) glucose, D(+) raffinose or D(+) galactose (Formedium, Hunstanton, UK), 20 g; Bacto-agar (for plates; Becton Dickinson and Co., MD, USA), 20 g; L-Isoleucine, 30 mg; L-Valine, 150 mg; L-Arginine-HCl, 20 mg; L-Histidine-HCl monohydrate, 20 mg; L-Leucine, 100 mg; L-Lysine-HCl, 30 mg; L-Methionine, 20 mg; L-Phenylalanine, 50 mg; L-Threonine, 200 mg; L-Tryptophan, 20 mg; L-Tyrosine, 30 mg; L-Glutamic acid, 20 mg; L-Aspartic acid, 20 mg; L-Serine, 100 mg and Uracil, 20 mg.