TABLE 2.

Effects of various competitors on the uptake of [14C]trehalose and [14C]sucrose in S. meliloti strains Rm1021, Sm7019, and Rm9628

CompetitorInhibition (%) of [14C]trehalose uptakeaInhibition (%) of [14C]sucrose uptakea
Sucrose-inducedTrehalose-inducedSucrose-inducedTrehalose-induced
Sm7019RM1021Rm9628Rm1021Sm7019Rm1021Rm9628Rm1021
None00000000
Cellobiose89700178491565
Glucose1318553339547968
Lactose40104918023
Maltose9190888984938294
Mannitol02119150146
Sucrose817212260000
Trehalose000081958295
  • a The results are expressed as mean percent inhibition of trehalose or sucrose uptake, and each value represents the mean for three different experiments. The transport rates with 1 μM concentrations of radiolabeled sugars served as control values. For competition studies, S. meliloti cultures were mixed with a 100-fold excess of the unlabeled sugar (100 μM) plus [14C]trehalose (1 μM) or [14C]sucrose (1 μM).