Mannose transport in Amphora coffeaeformis var. perpusilla (Bacillariophyceae)

Amphora coffeaeformis var. perpusilla is able to concentrate but not metabolize mannose. The sugar, which can be accumulated against a concentration gradient, is taken up only after a short lag. Preincubation with glucose allows immediate mannose uptake. Substances that reduce the ATP content of the diatom cells also inhibit mannose uptake, as do sugars of similar stereochemical configuration. Mannose appears to act as a non-metabolizable analogue of glucose in these respects.