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The photoautotrophic cyanobacterium Anacystis nidulans was used to investigate the membrane transport of branched-chain, neutral amino acids and its dependence on4photosynthetic reactions. The uptake of a-amino [1-14C]isobutyric acid and L-[1-1 C]leucine followed Michaelis-Menten kinetics and resulted in an energy-dependent accumulation. As in bacteria, different uptake systems for neutral amino acids were present: two DAG (D-alanine, aminoisobutyric acid, and glycine) systems responsible for uptake of a-amino [1-14C]isobutyric acid, and

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Effects of the chlorinated hydrocarbon insecticide Lindane on membrane transport of two neu trale amino acids in the Cyanobacterium Anacystis nidulans (Synechococcus AN) were measured. In white light the L-Leucine incorporation into the protein fraction was inhibited, increasing with time. After 30 minutes the degree of inhibition was the same as the effect of DCMU (5X 10-6 m) on L-Leucine incorporation. 14C 02-fixation was also reduced at this time. At 717 nm, which en ables PS I activity allone, no inhibition was observed. The light energy dependent membrane transport itself of L-leucine in presence of CAM and of the non-metabolisable a-AIB in white light and in monochromatic light of 630 nm and of 717 nm were not influenced by Lindane. The different sites of Lindane action are discussed. It is assumed that in 30 minutes chiefly photo synthesis (PS II and C 02-fixation) is affected by Lindane, resulting in a suppression of protein synthesis caused by a depletion of intermediates of C 02-fixation.