Physicochemical Basis of Information Processing in Ameboid Cells in Relation to Perception of Lower Organisms

1) halobium halobium表现出正、负趋光性。鉴定了趋光性受体。采用闪烁光解法和低温分光光度法研究了受体色素的光化学性质。单细胞生物能够感知环境的变化，并做出相应的行为，就像高等动物一样。研究了真黏菌多头绒泡菌的信息加工机制。这种生物在前部像一张纸一样伸展，复杂的静脉向后方发展，其中原生质的溶胶非常有规律地来回移动。这种规律动作的周期约为2分钟。由于这种有规律的运动伴随着静脉厚度的变化，因此可以观察到透射光的振荡信号。利用计算机图像处理技术分析了固有节奏的动态行为。当疟原虫的一部分受到温度、化学物质或光的刺激时，厚度振荡波在整个生物体中传播，在受刺激区域周围的相位分别被引诱剂或驱避剂提前或延迟。这表明，在疟原虫内的细胞内信息处理是有关的动态合作行为，在一个耦合的非线性振荡器群体。3)多头绒泡菌对uv -蓝光的趋光性为负。测定的作用谱与生成超氧阴离子的作用谱吻合较好。在缺氧的情况下，没有观察到负的趋向性。这些事实表明，超氧阴离子是负趋向性的中介。

1) Halobacterium halobium shows positive and negative phototaxis. Receptors of the phototaxis were identified. The photochemistry of receptor pigments was investigated with flash-photolysis and low-temperature spectrophotometry.2) Uni-cellular organisms are able to perceive changes of their environment behave accordingly just as higher animals do. A mechanism of information processing in true slime mold, Physarum polycephalum is investigated. This organism extends like a sheet at the frontal part, and intricate veins develop toward the rear, in which the protoplasmic sol moves to and fro very regularly.The period of this regular movement is about 2 minutes. Because this regular movement accompanies changes of the thickness of the vein, oscillatory signals of transmitted light can be observed. We have analyzed the dynamic behavior of the intrinsic rhythm with the help of computer image processing. When a part of the plasmodium is stimulated with temperature, chemicals or light, waves of thickness oscillation propagate throughout the organism, the phase around the stimulated region being advanced or retarded for attractants or repellents, respectively. This suggests that the intracellular information processing within the plasmodium is related to dynamic cooperative behavior in a population of coupled non-linear oscillators.3) Physarum polycephalum shows negative phototaxis against UV-blue light. Action spectrum was determined, which accords well with action spectrum for generation of super oxide anion. In the absence of oxygen, no negative taxis is observed. These facts imply that super oxide anion is a mediator for the negative taxis.