This is the website of Shimakawa's Lab in the University of Osaka (Graduate School of Science).
Please see the researchmap about the PI's CV.
Always welcome to questions, discussion, and collaboration on my research!
E-mail: gshimakawa.sci[at]osaka-u.ac.jp
News (updated in 2026.4.3)
Our new laboratory started on 1st April in 2026.
About my research
I explore a variety of research topics based on "Photosynthesis". My interest is often too much broad and messy, but it would be fine when I am still young.
Several research topics are briefly described as follows:
Photosynthetic quotient and biodiversity：The ratio of O2 evolution to CO2 fixation in photosynthesis is defined as "Photosynthetic quotient", which reflects how much light energy absorbed is utilized for photosynthesis (the value closer to 1.0 means the larger energy used for photosynthesis). I hypothesize that each photosynthetic organism in various environments show the optimum photosynthetic quotient, and try to elucidate the biodiversity of plants, algae,and cyanobacteria in this view. This study is on going as a part of "Photosynthesis Ubiquity".
Initiation of leaf senescence：Initiation of leaf senescence should be modulated by plants dependent on the physiological states and environmental conditions, but the mechanism is still unclear. We have previously found that the decrease in plastocyanin (PC; an electron carrier protein) can be utilized to detect the initiation of leaf senescence. With this in vivo bio-marker, I try to uncover the molecular mechanism modulating the timing of leaf senescence.
Organization of chloroplast architecture：Photosynthetic organisms possess various chloroplast architectures. For example, the plant chloroplasts have the two-layer envelopes and the thylakoid membranes, a part of which is stucked (named as grana). Meanwhile, the diatom chloroplasts are surrounded by the four-layer membranes and have the membrane-less compartment "pyrenoid", in which the CO2-fixing enzyme is condensed and to which a part of thylakoid membranes is penetrated. I try to see how and why such a unique chloroplast architecture is organized.
Endosymbiosis of Symbiodiniaceae in corals：Reef-building corals have the endosymbiotic dinoflagellates to obtain photosynthates from them. I try to see how the symbiotic algae perform photosynthesis in the host cells and if the photosynthetic activity is modulated by the host corals.