RNA World is a one of the widely accepted hypotheses for the origin of life. To hold the validity of the hypothesis, the synthetic pathways which provide RNA building blocks under prebiotically plausible conditions must be demonstrated. The separate pathways to purines and pyrimidines have been reported so a far, but their concurrent syntheses remain a critical issue. Here we describe our recent research on the unified prebiotic synthesis of the pyrimidine and purine nucleosides from small molecules and ribose driven by wet-dry cycles.

  The origin of the eukaryotic cell is one of the biggest mysteries in the evolution of life. Recent advances in metagenomics revealed genes of eukaryotic signature proteins (ESPs) in archaea and bacteria, suggesting that the primitive form of cellular complexity could exist before the emergence of eukaryotic cells. Among them, the actin cytoskeleton is of particular interest because it could have led to eukaryotic morphological dynamics including the endosymbiotic acquisition of a mitochondrial ancestor. However, it is still challenging to perform functional studies of metagenomic genes due to the lack of culture systems and technical difficulty in the biology of non-model organisms. As an alternative approach, here I introduce artificial cell technology. Artificial cell is a model system to study biological functions in reconstituted cell-sized, lipid membrane-bound compartments. In this article, I review recent advances in artificial cell technology, featuring actin cytoskeleton, and discuss potential applications to study the origin of eukaryote.

  A flow reactor simulating a submarine hydrothermal system was constructed for examining the likelihood of oligopeptide synthesis from amino acids in chemical evolution. In the flow reactor, is a high-temperature and high-pressure fluids was injected into a low-temperature chamber maintained at almost the same high pressure as the fluid and it is a non-equilibrium open system reactor that is constantly supplies reactants and thermal energy. Here, I describe the configuration of the flow reactor, the experimental results using it, and the problem of the flow reactor as experimental tool for simulating hydrothermal environments.