Zhao Jingquan

Generation and identification of the transient intermediates of allophycocyanin by laser photolytic and pulse radiolytic techniques

Purpose : To explore the photophysical and photochemical properties of allophycocyanin (APC) and contribute to the understanding of the molecular mechanism of APC photosensitization. Materials and methods : Laser-flash photolytic and pulse radiolytic techniques were used for the first time to characterize the transient intermediates involved in APC photochemistry and photophysics. The excited triplet state and radical cation of APC were identified by acetone sensitization and one-electron oxidation. Results : The 248-nm laser-flash photolysis of APC in N 2 -saturated aqueous solution (pH 7.0) yields the triplet state and radical cation of APC. The APC radical cations were generated by ionization via a monophotonic process, with a quantum yield of 0.17. Conclusions : APC can undergo both photo-excitation and photo-ionization under the present experimental conditions. These new findings suggest that APC has the potential to act as both a type I and type II photosensitizer.

Progress in phototaxis mechanism research and micromanipulation techniques of algae cells

Abstract Phototactic movement is a characteristic of some microorganisms, response to light environment. Most of the algae have dramatically phototactic responses, underlying the complicated biological, physical and photochemical mechanisms are involved. With the development of the micro/nano and sensor techniques, great progress has been made in the research of the algae phototaxis. This review article summarizes the progress made in the research on the functional phototactic structures, the mechanisms of photo-response process and photodynamics of phototaxis in algae, and describes the latest developed micro-tracking technique and micromanipulation technique. Moreover, based on our o research results, the potential correlation between the phototaxis and photosynthesis is discussed, and the directions for future research of the phototactic mechanism are proposed. *Supported by National Natural Science Foundation of China (Grant No. 30570422)