FIG. 2.

Intracellular d-[¹⁴C]mannitol in cell extracts from wild-type and uncoupled mutant strains. Cells of strain LGS323 [ΔmtlA55 Δ(gut-rec)63] (lane 1) and cells of transformants of this strain with the wild-type allele of mtlA on pGJ9 (lanes 2 and 3) or with the uncoupled allele on pGJ9 H256P (lane 4) were incubated for 5 min with 280 μM d-[¹⁴C]mannitol at 25°C, washed, and extracted as described in Material and Methods. Portions (5 μl) of the supernatants were applied to Nono-Sil G plates and developed in 1-butanol-ethanol-water (3:1:1). In lane 3, 1.6 × 10⁴cpm of d-[¹⁴C]mannitol was added to each of the cell extracts before application to the gel plates. Free d-mannitol and several metabolic derivatives of mannitol 1-phosphate in the wild type were visualized by radioautography. WT, wild type.