Photosynthesis and Photobiological Studies of Microalgae

这个研究项目的前负责人，Shigetoh Miyachi，他与Senger教授合作，证明了在普通空气中生长的某些绿色藻类光合作用的量子效率（低CO^2细胞）低于在3%CO^2下生长的细胞（高CO^2细胞），低温下710-740 nm处的叶绿素荧光强度高于低CO^2细胞680-695 nm处的叶绿素荧光强度。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。它们还显示出在原叶绿素氧化还原酶的活化中需要Ca^<2+>。Tsuzuki与Senger教授一起研究了利用栅藻突变体从叶绿素a到B的转化。Ohmori发现在蓝藻中存在cAMP和GTP结合蛋白，并且在光照下cAMP水平发生显着变化。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。他们还认为蛋白质是一种可能的光感受器。尽管如此，他还是与Wehrmeyer教授讨论了用电子显微镜测定感光蛋白的可能性。渡边和森格尔教授一起进行了实验，以显示蓝藻中两种光系统在不同波长、光强和CO^2浓度下的比例。PS I/II的比值受前两个因子的影响较大，而受CO^2浓度的影响较小。并讨论了在光系统Ⅰ反应中心观察到的叶绿素a'的可能功能。Watanabe为人工合成叶绿素a二聚体的表征提供了前景。Igarashi从嗜热蓝细菌中分离出Rubisco，并发现Rubisco在高温下稳定。他与Thauer教授讨论了极端环境下生长的微生物固定CO^2的数据和特性，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.