Physicochemical Study on Intra-callular Information Processing

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Physarum polycephalum is a giant amoeboid cell as is leutocyte. The use of ginat cells enables to measure spatial and time-dependent change in components or substances constituting the cell. Due to its small in size, this kind of experiment cannot performed with leutocyte. We measure the spatial variation of phospholipid composition. At the frontier of cell, the content of phosphatidylethanolamine (PE) is 46 % of all phospholipids and that of phosphatidylcholine (PC) is 32 %. The contents of other phospholipids aer : phosphatidylinotitol (PI), 8% ; phosphatidylserine (PS), 6% ; cardiolipin (CL), 4% and phosphatidic acid (PA), 4%. The content of PE decreases as the location becomes interior while that of PC increases. At the position of about 2 cm from the frontier, the contents of PE and PC are almost equal, and these are 41 % and 38 %, respectively. When CaCl_2 is applied, the cell shows avoidance reaction. The application of this chemical changes the phospholipids composition spatial … More ly and time dependently. The relationship between these changes in phospholipid composition and avoidance reaction of the cell is awaited for further investigation.2. Irradiation of ultraviolet light to living organism induces avoidance reaction and produces reactive oxygen. The production of reactive oxygen is not experimentally verified. We develop a sensitive and convenient method for detection of intracelluar H_2 O_2. With this method, we can first show the production of reactive oxygen of keratinocyte. For the blood-transfusion of platelet, contamination of lympocytes leads to unfavorable immune reaction. Although it is known that irradiation of ultraviolent light is effective to eliminate the immune reaction, the mechanism is not clear yet. We can suggest that the reactive oxygen is involved.3. Phoborhodopsin (PR) is a receptor of negative photo-taxis of Halobacterium halobium. We succeed in purifying this receptor protein, PR from halophilic and alkaliphilic bacterium and clarify the detailed photochemical reactions. Less