Uptake of radiolabeled dimethylsulfoniopropionate (35S-DMSP) by E. coli wild-type and mutant strains complemented with candidate DMSP transporter genes from Ostreococcus tauri

Uptake (as dpm/mL/OD) of 35S-DMSP by several strains of Escherichia coli: (a) the wild type DH5α, which harbors a betaine-carnitine-choline transporter (BCCT); (b) MKH13, a mutant that is BCCT deficient ; (c) MKH13 + BCCT-1, a MKH13 that has been complemented with the BCCT-1 gene (as DMSP carrier candidate) from the picaoalga Ostreococcus tauri; (d) MKH13 + BCCT-2, a MKH13 that has been complemented with the BCCT-2 gene (as DMSP carrier candidate) from the picaoalga Ostreococcus tauri; (e) MKH13 + empty vector, a MKH13 complemented with the empty plasmid pBAD33 used above as the expression vector for BCCT genes. Killed controls (where the strains had been killed with fixatives before being assayed for 35S-DMSP uptake) are also shown a a 'zero 'reference.