Influence of Light Conditions, Gassing and Inhibitors on Photophosphorylation and ATP-Level in Anacystis Nidulans

Abstract

From several experiments it seems to be well established, that in vivo besides noncyclic photophosphorylation or its pseudocyclic subtype under appropriate conditions also a cyclic photophosphorylation occurs (URBACH & SIMONIS 1964, TANNER et al. 1966, WIESSNER 1965, URBACH & GIMMLER 1970). Some years ago FORTI & PARISI (1963) measured the ATP-level in photosynthetica11y active cells of leaves. They observed that by illumination the ATP-pool increased in a short time in air as well as under nitrogen. Addition of CMU, even in high concentration, had no effect. Therefore it was concluded, that the ATP-level in these leaves is maintained by cyclic photophosphorylation, which is not inhibited by CMU and occurs also under anaerobic conditions (ARNON 1967). In the meantime ATP-measurement by the firef1y-1uciferase luminescence test, introduced by STREHLER (1952) became well established (WELSCH & SMITH 1969, URBACH & GIMMLER 1971). To gain more information about the different types of photophosphorylation in vivo we took advantage of this method in short time experiments. But instead of the higher differentiated leaves and other measurements in this institute by URBACH & GIMMLER (1971) with unicellular green algae, we used the less compartimented blue-green algae Anacystis nidulans, which lacks the chloroplast membrane. Beyond that, Anacystis in particular may be suitable to differentiate between the diverse types of photophosphorylation using monochromatic light of different wavelengths.