Photosynthesis and Photobiological Studies of Microalgae

该项目的前负责人Shigetoh Miyachi与Senger教授合作，发现在普通空气下生长的一些绿藻（低CO^2细胞）光合作用的量子效率低于在3% CO^2条件下生长的细胞（高CO^2细胞），低温下710-740 nm的叶绿素荧光高于低CO^2细胞680-695 nm的叶绿素荧光。这些结果表明，光系统I在低co ^2细胞中比在高co ^2细胞中更活跃。在原叶绿内酯氧化还原酶的活化过程中也显示了Ca^<2+>的需求。Tsuzuki与Prof. Senger利用Scenedesmus突变体研究了叶绿素a向b的转化。Ohmori在蓝藻中发现了cAMP和gtp结合蛋白的存在，并在光照下显示出cAMP水平的显著变化。在实验过程中，他与Senger教授和Galland博士讨论了蓝藻中光信号转导机制的数据。他们还认为蛋白质可能是一种光感受器。他还与Wehrmeyer教授讨论了用电子显微镜测定光感受器蛋白的可能性。Watanabe教授与Senger教授一起进行了实验，以显示蓝藻中不同波长、光强度和CO^2浓度下两个光系统的比例。PS I / II的比值受前两个因子的影响，但受CO^2浓度的影响不大。他们还讨论了在光系统I反应中心观察到的叶绿素a'可能的功能。这为人工合成的叶绿素a调光剂的表征开辟了前景。Igarashi从嗜热蓝藻中分离出Rubisco，发现Rubisco在高温下是稳定的。他与Thauer教授讨论了在极端环境下生长的微生物固定co2的数据和特点，并谈到了未来的合作。

The former head of this research program, Shigetoh Miyachi, cooperated with Prof. Senger and showed that quantum efficiency in photosynthesis of some green algae grown under ordinary air (low-CO^2 cells) was lower than the cells grown under 3% CO^2 (high-CO^2 cells) and that chlorophyll fluorescence at low temperature at 710-740 nm was higher than that at 680-695 nm in low-CO^2 cells. These results suggests that photosystem I is more active in low-CO^2 cells than in high-CO^2 cells. They also showed Ca^<2+> requirement in the activation of protochlorophyllide oxidoreductase. Tsuzuki investigated the conversion from chlorophyll a to b using Scenedesmus mutant with Prof. Senger. Ohmori found the existence of cAMP and GTP-binding protein in-cyanobacteria and showed remarkable changes in the levels of cAMP by the exposure to light. During the experiments, he discussed the data the mechanism of signal transduction by light in cyanobacteria with Prof. Senger and Dr. Galland. They also considered protein as a possible photoreceptor. Still, he discussed a possibility of electron microscope for determination of photoreceptor protein with Prof. Wehrmeyer. Watanabe carried out experiments with Prof. Senger to show the ratio of two photosystems at various wavelength, light intensity, and CO^2 concentration in cyanobacteria. The ratio of PS I over II was changed by the former two factors, but little by CO^2 concentration. They also discussed the possible function of chlorophyll a' observed in photosystem I reaction center. It was good for Watanabe to obtain a prospect for characterization of chlorophyll a' dimmer prepared artificially. Igarashi has isolated Rubisco from a thermophilic cyanobacterium and found that the Rubisco is stable at high temperature. He discussed the data as well as characteristics of CO^2 fixation of microorganisms grown under extreme environment with Prof. Thauer and talked about future cooperation.