A5005986368- Microbial Natural Products and Biosynthesis
- Origins and Evolution of Life
- Geochemistry and Elemental Analysis
- Synthetic Organic Chemistry Methods
- Mass Spectrometry Techniques and Applications
- Geology and Paleoclimatology Research
- Traditional and Medicinal Uses of Annonaceae
- Photoreceptor and optogenetics research
- Carbohydrate Chemistry and Synthesis
- Microbial Metabolic Engineering and Bioproduction
- RNA and protein synthesis mechanisms
- Advanced Proteomics Techniques and Applications
- Protein Structure and Dynamics
- Analytical Chemistry and Chromatography
- Natural product bioactivities and synthesis
- Chemical Synthesis and Analysis
- Chemical Synthesis and Characterization
- Marine Sponges and Natural Products
- Enzyme Structure and Function
- Enzyme Catalysis and Immobilization
- Peptidase Inhibition and Analysis
- Paleontology and Stratigraphy of Fossils
- Mercury impact and mitigation studies
- Sesquiterpenes and Asteraceae Studies
- Cephalopods and Marine Biology
Okinawa Institute of Science and Technology Graduate University
2019-2024
RIKEN Center for Sustainable Resource Science
2014-2024
Life Science Institute
2016-2022
Tokyo Institute of Technology
2017-2022
RIKEN
2006-2016
Earth-Life Science Institute
2016
Nippon Soken (Japan)
2014
Sanken Electric (Japan)
2013
RIKEN Advanced Science Institute
2007-2011
Waseda University
2011
Significance The prebiotic milieu was likely heterogeneous, consisting of a large number chemicals and their associated reactions, including those not only biological compounds, but also nonbiological compounds. Although origins life research has focused primarily on molecules, the molecules which were present may have assisted evolving chemical systems in unforeseen ways. Thus, we synthesized assembled membraneless polyester microdroplets from drying pools simple α-hydroxy acid monomers...
We have recently shown that 2-aminoimidazole is a superior nucleotide activating group for nonenzymatic RNA copying. Here we describe prebiotic synthesis of shares common mechanistic pathway with 2-aminooxazole, previously described key intermediate in synthesis. In the presence glycolaldehyde, cyanamide, phosphate and ammonium ion, both 2-aminooxazole are produced, higher concentrations ion acidic pH favoring former. Given 1:1 mixture glyceraldehyde preferentially reacts cyclizes latter,...
Abstract It is widely believed that the origin of life depended on environmentally driven complexification abiotically produced organic compounds. Polymerization one type such complexification, and it may be important many diverse polymer sequences for sake selection. Not all compound classes are easily polymerized under environmental conditions present primitive planets, possible life’s was aided by other monomers besides those used in contemporary biochemistry. Here we show alpha-hydroxy...
Water creates special problems for prebiotic chemistry, as it is thermodynamically favorable amide and phosphodiester bonds to hydrolyze. The availability of alternative solvents with more properties the formation molecules on early Earth may have helped bypass this so-called "water paradox". Formamide (FA) one such solvent, can serve a nucleobase precursor, but difficult envision how FA could been generated in large quantities or accumulated terrestrial surface environments. We report here...
We present novel data sets of rare earth element (REE) distributions in a hydrothermal vent field at Yonaguni Knoll IV the Okinawa Trough. Vertical REE profiles three water columns showed horizontal variation concentrations within 1000–1200 m. Hydrothermal plumes were discovered by anomalous values methane, manganese and transmissometry that site. Europium anomalies North Pacific deep (NPDW) (Nozaki et al., 1999) normalized pattern decreased with distance from site, indicating dilution fluid...
Synthesis of (23E)-cycloart-23-ene-3β,25-diol (1) and its 23Z-isomer 2 was achieved by using cycloartenol as a starting material, thus revising the proposed structure natural to 1 unequivocally. These synthetic studies revealed that structural revision (Z-form → E-form) should also be applied terpenoids such (23Z)-3β-acetoxyeupha-7,23-diene-25-ol, (23Z)-tirucalla-7,23-diene-3β,25-diol, quadrangularol A, quadrangularic acid K, daurichromene C.
We report the syntheses of ribonucleoside 5'-monophosphates activated with imidazole, using a mechanism which relies on in situ generation cyanogen chloride from reaction cyanide anion hypochlorous acid. Cyanogen reacts rapidly imidazole to form diimidazole imine as major product, species affords activation their 5'-phosphorimidazolides.
Although the rare earth element (REE) geochemistry of hydrothermal systems have intensively been investigated at mid-oceanic ridges, studies are relatively few converging plate zones like Okinawa Trough. The “chimney” deposits obtained by using submersible “SHINKAI 2000” from Iheya Ridge site, Trough largely composed massive carbonates and silicates with minor amounts sulfides, appear black white depending upon their composition. concentrations REEs 2–3 orders magnitude higher in...
Lysophospholipids are important signaling molecules in animals and metazoan cells. They widely distributed among marine invertebrates, where their physiological roles unknown. Sea cucumbers produce unique lysophospholipids. In this study, two lysophospholipids were detected Holothuria atra for the first time, lyso-platelet activating factor lysophosphatidylcholine, with nuclear magnetic resonance liquid chromatography–time-of-flight mass spectrometric analyses. The lipid fraction of H....
Total synthesis of the proposed structure 2 for phomopsin B was achieved by using an intramolecular olefin metathesis as a key step. The spectral data, however, did not match with those natural product reported. Re-examination reported NMR data led to structural revision known dothiorelone A 18. R configuration determined total through cross-metathesis chiral 19.
This paper describes a second-generation synthesis of an antitumor tetrahydropyran (THP) acetogenin, pyragonicin. The key step involved olefin cross-metathesis between the THP segment and terminal γ-lactone residue. coupling reaction in presence Grubbs' catalyst resulted unseparable mixture desired product its one-carbon eliminated while use first-generation afforded former exclusively. A novel MOM-migrating found cyclization is also discussed.
The first total syntheses of acetogenin 3 and its 4S,8R-isomer are described. key step involves intermolecular metathesis an α,β-unsaturated ketone carrying a tetrahydropyranyl lactone with tetrahydrofuran derivative. Compound has spectroscopic physical data consistent those natural montanacin D, suggesting that the absolute configuration product is as shown in 3.
Abstract Chemical evolution, from simple molecules to complex systems, is fundamental modern origins of life research, and reaction networks are often supposed have operated on the early Earth. Herein, a variety compounds useful particularly for RNA synthesis − namely, cyanogen chloride, cyanamide, nitrile precursors sugars produced in short order by chemical network starting hydrogen cyanide driven gamma radiolysis. The radiolytic yield cyanamide was found be proportional concentration an...
Polymerization of nucleotides under prebiotically plausible conditions has been a focus several origins life studies. Non-activated have shown to undergo polymerization geothermal when subjected dry-wet cycles. They do so by mechanism similar acid-catalyzed ester-bond formation. However, one study showed that the low pH these reactions resulted in predominantly depurination, thereby resulting formation abasic sites oligomers. In this study, we aimed systematically characterize nature...
Abstract Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence high-quality NH 4 + and glutamate (Glu), which called catabolite repression. Amino acid auxotrophic mutants fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing Cl or Glu even when adequate amounts required supplied. However, growth these mutant cells was recovered vicinity colonies prototrophic strain, suggesting that secrete some substances can...
Total synthesis of 4 and its three diastereomers is described. The key steps involve stereoselective formation the tetrahydrofuran ring by a cascade cyclization hydroxy tosylate 7 an intermolecular cross metathesis between 5 gamma-lactone 6. Spectroscopic data biosynthetic hypothesis strongly suggest it to be montanacin E. Inhibitory activities isomers against six human solid tumor cell lines were also evaluated.