The successful functioning of eukaryotic cells is dependent upon a highly organized intracellular cooperation and interaction between the numerous compartments which are present in them. In recent years unicellular algae have become increasingly recognized as favoured objects for studies on struc- tural, biochemical and developmental aspects of compartmentation. Promp- ted by these facts, Professor A. Pirson, former Directior of the Plant Physio- logy Institute in Gottingen, suggested organizing a symposium entitled Com- partments in Algal Cells and Their Interaction. This was then organized under the auspices of the Akademie der Wissen- schaften in Gottingen with the fmancial support of the Stiftung Volkswa- genwerk. The meeting took place in Gottingen in September of 1983 and was attended by a number of internationally renowned colleagues. The re- stricted size of the meeting, together with the convivial atmosphere, led to an optimal exchange of views between the participants. This book presents the proceedings of this meeting and contains all the papers presented. We feel, however, that it contains information of use to a much larger circle of scientists than to phycologists alone. We should like to take this opportunity to express our thanks to all those involved in the convention, support and in day-to-day operation of the meeting. We also thank the contributors for their quick and effective co- operation and, last but not least, the editorial staff of Springer Verlag, who enabled this book to appear only 9 months after the meeting took place, thus ensuring its up-to-date nature.

Although the 32 kOa-polypeptide (0-1) is a minor component of thyla- koids in algae and higher plants. much attention has been focused on it. It was shown to be the binding site for herbicides (Pfister et al. 1981). the rapidly synthesized polypeptide of thylakoid membranes (Edelman and Reisfeld 1978; Owens et al. 1982) and to participate in Qa binding (Arntzen et al. 1984; Kyle et al. 1984; Ohad et al. 1984). Measurements of the stoichiometry of the various PS II polypeptides in C. reinhardii showed that thylakoids contain about one herbicide binding polypeptide per one PS II unit and the accelerated light sti- mulated turnover of the 32 kOa-polypeptide was postulated to be the consequence of its function in quinone reduction. Based on comparison of amino acid sequence and hydropathy profile homologies of 0-1 and 0-2 with the subunits of the bacterial photosystem. recently a model was presented. in which the reaction center of photosystem II in algae and higher plants is formed by the polypeptides 0-1 and 0-2 (Trebst 1986). The structural gene of the 32 kOa-polypeptide (psbA) has been mapped on the chloroplast DNA and cloned from various plant species (for a review: Kyle 1985). The polypeptide is synthesized as a precursor on ribosomes bound to unstacked lamellae and there proc- essed to its mature form (Edelman and Reisfeld 1978; Herrin and Michaels 1985). In C. reinhardii the 0-1 polypeptide is phosphorylat- ed by a light-activated membrane bound kinase.