The construction of a protocell from a materials point of view is important in understanding the origin of life. Both self-reproduction of a compartment and self-replication of an informational substance have been studied extensively, but these processes have typically been carried out independently, rather than linked to one another. Here, we demonstrate the amplification of DNA (encapsulated guest) within a self-reproducible cationic giant vesicle (host). With the addition of a vesicular membrane precursor, we observe the growth and spontaneous division of the giant vesicles, accompanied by distribution of the DNA to the daughter giant vesicles. In particular, amplification of the DNA accelerated the division of the giant vesicles. This means that self-replication of an informational substance has been linked to self-reproduction of a compartment through the interplay between polyanionic DNA and the cationic vesicular membrane. Our self-reproducing giant vesicle system therefore represents a step forward in the construction of an advanced model protocell.

Tutorial review: to achieve molecule-based spintronic devices, an organic conducting magnet that exhibits both conductivity and magnetism in a cooperative manner must be constructed. As a building block for such new materials, a spin-polarized donor radical, which serves as a molecular "spin-filter" in its singly oxidized state, was designed and synthesized. The resistivity of ion radical salts of selenium-substituted, tetrathiafulvalene-based spin-polarized donor radicals decreased substantially in the presence of a magnetic field, thus indicating cooperative conductivity and magnetism.

Self-organized lipid structures (protocells) have been proposed as an intermediate between nonliving material and cellular life. Synthetic production of model protocells can demonstrate the potential processes by which living cells first arose. While we have previously described a giant vesicle (GV)-based model protocell in which amplification of DNA was linked to self-reproduction, the ability of a protocell to recursively self-proliferate for multiple generations has not been demonstrated. Here we show that newborn daughter GVs can be restored to the status of their parental GVs by pH-induced vesicular fusion of daughter GVs with conveyer GVs filled with depleted substrates. We describe a primitive model cell cycle comprising four discrete phases (ingestion, replication, maturity and division), each of which is selectively activated by a specific external stimulus. The production of recursive self-proliferating model protocells represents a step towards eventual production of model protocells that are able to mimic evolution.

In the multicolor photochromism of TiO2 nanoporous films loaded with photocatalytically deposited Ag nanoparticles, visible light-induced electron transfer from Ag to oxygen molecules plays an essential role. Here we examined the effect of TiO2 on the electron transfer. We found that not only photocatalytically deposited Ag, but also electrodeposited Ag and commercially available Ag nanoparticles in a nanoporous TiO2 film exhibit the multicolor photochromism. The electrodeposited Ag exhibits the multicolor photochromism also in a nanoporous ZnO film, but not in nanoporous indium-tin oxide (ITO) and SiO2 matrices. Photoelectrochemical measurements for the Ag-TiO2 nanocomposite elucidated that some of the photo-excited electrons on Ag are transferred to oxygen molecules via TiO2 and non-excited Ag. Thus, an n-type semiconductor plays an important role in the charge separation between the excited electrons and Ag+. Non-excited Ag on TiO2 also plays an important role in the charge separation and/or catalysis of oxygen reduction. Replacement of the non-excited Ag with Pt accelerated the electron transport from the photo-excited Ag to oxygen molecules and the photochromic behavior.

Feruloyl esterase (FAE) catalyzes the hydrolysis of the ferulic and diferulic acids present in plant cell wall polysaccharides, and tannase catalyzes the hydrolysis of tannins to release gallic acid. The fungal tannase family in the ESTHER database contains various enzymes, including FAEs and tannases. Despite the importance of FAEs and tannases in bioindustrial applications, three-dimensional structures of the fungal tannase family members have been unknown. Here, we determined the crystal structure of FAE B from Aspergillus oryzae (AoFaeB), which belongs to the fungal tannase family, at 1.5 Å resolution. AoFaeB consists of a catalytic α/β-hydrolase fold domain and a large lid domain, and the latter has a novel fold. To estimate probable binding models of substrates in AoFaeB, an automated docking analysis was performed. In the active site pocket of AoFaeB, residues responsible for the substrate specificity of the FAE activity were identified. The catalytic triad of AoFaeB comprises Ser203, Asp417, and His457, and the serine and histidine residues are directly connected by a disulfide bond of the neighboring cysteine residues, Cys202 and Cys458. This structural feature, the "CS-D-HC motif," is unprecedented in serine hydrolases. A mutational analysis indicated that the novel structural motif plays essential roles in the function of the active site.

GH3 (glycoside hydrolase family 3) BGLs (β-glucosidases) from filamentous fungi have been widely and commercially used for the supplementation of cellulases. AaBGL1 (Aspergillus aculeatus BGL1) belongs to the GH3 and shows high activity towards cellooligosaccharides up to high degree of polymerization. In the present study we determined the crystal structure of AaBGL1. In addition to the substrate-free structure, the structures of complexes with glucose and various inhibitors were determined. The structure of AaBGL1 is highly glycosylated with 88 monosaccharides (18 N-glycan chains) in the dimer. The largest N-glycan chain comprises ten monosaccharides and is one of the largest glycans ever observed in protein crystal structures. A prominent insertion region exists in a fibronectin type III domain, and this region extends to cover a wide surface area of the enzyme. The subsite +1 of AaBGL1 is highly hydrophobic. Three aromatic residues are present at subsite +1 and are located in short loop regions that are uniquely present in this enzyme. There is a long cleft extending from subsite +1, which appears to be suitable for binding long cellooligosaccharides. The crystal structures of AaBGL1 from the present study provide an important structural basis for the technical improvement of enzymatic cellulosic biomass conversion.

Marcasite-type rhodium nitride was successfully synthesized in a direct chemical reaction between a rhodium metal and molecular nitrogen at 43.2 GPa using a laser-heated diamond-anvil cell. This material shows a low zero-pressure bulk modulus of K0 = 235(13) GPa, which is much lower than those of other platinum group nitrides. This finding is due to the weaker bonding interaction between metal atoms and quasi-molecular dinitrogen units in the marcasite-type structure, as proposed by theoretical studies.

The last remaining marcasite-type RuN2 was successfully synthesized by direct chemical reaction between ruthenium and molecular nitrogen above the pressure of 32 GPa. For the first time, we found that Ru 4d is weakly hybridized with N 2p in the structure by using transmission electron microscopy equipped with electron-energy-loss spectroscopy. Our finding give important knowledge about the platinum-group pernitride with respect to the chemical bonding between platinum-group element and nitrogen.