Glucose induces two amino acid transport systems in Chlorella.

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Abstract
In autotrophically grown Chlorella cells, glucose induces a hexose transport system but, at the same time, the synthesis of 2 amino acid transport systems is induced. The rates of uptake of glycine, L-alanine, L-proline and L-serine, all of which compete with each other for entry into the cells, increase more than 100-fold when the algae are pretreated with glucose. The rates of L-arginine and L-lysine uptake increase by a factor of 25-50. The accumulation of proline and arginine within the cells amounts to 200- and 600-fold, respectively. Glucose does not cause the positive effect on amino acid uptake by serving as metabolic substrate because the nonmetabolizable 6-deoxyglucose also acts as inducer. Cycloheximide prevents the induction. The induced transport system for the 4 neutral amino acids has a turnover with a half-life of 7 h, which corresponds closely to the half-life of the hexose transport system. The transport system for the basic amino acids disappears with a half-life of 25 h.