Several essential points of photosynthetic light reactions were reviewed for future development of this scientific field and a general interest of biophysicists. Historical backgrounds of the reaction systems were also stated for the continuity of problems. Main points are reaction schemes and mechanisms of photochemical reactions in reaction center complexes, oxygen evolution, i.e. water cleavage and a high redox potential for water oxidation, and structures of reaction center complexes. These points will be solved by combination of spectroscopy and molecular biology. Photosynthesis will be utilized for our survival in the 21st century through their potentials in food supply, solar energy conversion and sustainable environmental preservation.
Vertebrate segmentation is controlled by a developmental time-keeper, called “segmentation clock”. The segmentation clock, being an ensemble of cellular oscillators, displays a well-organized transcriptional oscillation both at the cell and tissue levels. Here we review our recent analysis on the clock population, which incorporated a combinatorial analysis of mathematical and experimental techniques, then discuss the mechanism and significance of intercellular communication to achieve a noise-resistant and synchronized oscillation.
In the vertebrate retina, there are two types of photoreceptor cells, called rods and cones. Rods mediate twilight vision and cones mediate daylight vision. In accordance with their functional differences, their photoresponse characteristics are different from each other. However, little is known about the molecular bases in the differences of the photoresponse characteristics between rods and cones. Recently, we developed a method to purify cones from carp (Cyprinus carpio) retina, which made it possible to analyze the molecular mechanisms underlying the response differences between rods and cones. In this review, elucidated mechanisms are shown based on our recent results.
CIA is the most conserved histone chaperone in the eukaryotes. The biochemical and X-ray crystallographic studies have revealed that CIA splits the histone (H3-H4)2 tetramer into two histone H3-H4 dimers through the CIA-histone-H3-H4 complex formation. The histone (H3-H4)2 tetramer splitting activity of CIA gives new insights into the mechanism of the nucleosome assembly/disassembly, the relationship between nucleosome assembly/disassembly and epigenetic modifications of histones, and the mechanism of the epigenetic information inheritance through the semi-conservative nucleosome replication mode.