-
Article
Open AccessThe impact of crystal phase transition on the hardness and structure of kidney stones
Calcium oxalate kidney stones, the most prevalent type of kidney stones, undergo a multi-step process of crystal nucleation, growth, aggregation, and secondary transition. The secondary transition has been rat...
-
Article
Open AccessAtmospheric formaldehyde production on early Mars leading to a potential formation of bio-important molecules
Formaldehyde (H2CO) is a critical precursor for the abiotic formation of biomolecules, including amino acids and sugars, which are the building blocks of proteins and RNA. Geomorphological and geochemical evidenc...
-
Article
Open AccessHexose phosphorylation for a non-enzymatic glycolysis and pentose phosphate pathway on early Earth
Glycolysis and pentose phosphate pathways play essential roles in cellular processes and are assumed to be among the most ancient metabolic pathways. Non-enzymatic metabolism-like reactions might have occurred...
-
Article
Open AccessBoron-assisted abiotic polypeptide synthesis
The emergence of proteins and their interactions with RNAs were a key step in the origin and early evolution of life. The abiotic synthesis of peptides has been limited in short amino acid length and is favore...
-
Article
Open AccessThe spatial distribution of soluble organic matter and their relationship to minerals in the asteroid (162173) Ryugu
We performed in-situ analysis on a ~ 1 mm-sized grain A0080 returned by the Hayabusa2 spacecraft from near-Earth asteroid (162173) Ryugu to investigate the relationship of soluble organic matter (SOM) to minerals...
-
Article
Open AccessDistributions of CHN compounds in meteorites record organic syntheses in the early solar system
Carbonaceous meteorites contain diverse soluble organic compounds. These compounds formed in the early solar system from volatiles accreted on tiny dust particles. However, the difference in the organic synthe...
-
Article
Open AccessBorate-guided ribose phosphorylation for prebiotic nucleotide synthesis
Polymers of ribonucleotides (RNAs) are considered to store genetic information and promote biocatalytic reactions for the proto life on chemical evolution. Abiotic synthesis of ribonucleotide was successful in...
-
Article
Open AccessIdentifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites
The lack of pyrimidine diversity in meteorites remains a mystery since prebiotic chemical models and laboratory experiments have predicted that these compounds can also be produced from chemical precursors fou...
-
Article
Open AccessMulticolor imaging of calcium-binding proteins in human kidney stones for elucidating the effects of proteins on crystal growth
The pathogenesis of kidney stone formation includes multi-step processes involving complex interactions between mineral components and protein matrix. Calcium-binding proteins in kidney stones have great influ...
-
Article
Open AccessAnalytical protocols for Phobos regolith samples returned by the Martian Moons eXploration (MMX) mission
Japan Aerospace Exploration Agency (JAXA) will launch a spacecraft in 2024 for a sample return mission from Phobos (Martian Moons eXploration: MMX). Touchdown operations are planned to be performed twice at di...
-
Article
Open AccessAqueous alteration without initial water: possibility of organic-induced hydration of anhydrous silicates in meteorite parent bodies
Early evolution of Solar System small bodies proceeded through interactions of mineral and water. Melting of water ice accreted with mineral particles to the parent body results in the formation of secondary m...
-
Article
Open AccessExtraterrestrial hexamethylenetetramine in meteorites—a precursor of prebiotic chemistry in the inner solar system
Despite extensive studies on the formation of organic molecules in various extraterrestrial environments, it still remains under debate when, where, and how such molecules were abiotically formed. A key molecu...
-
Article
Open AccessImpact-induced amino acid formation on Hadean Earth and Noachian Mars
Abiotic synthesis of biomolecules is an essential step for the chemical origin of life. Many attempts have succeeded in synthesizing biomolecules, including amino acids and nucleobases (e.g., via spark dischar...
-
Article
Open AccessThe Importance of Phobos Sample Return for Understanding the Mars-Moon System
Phobos and Deimos occupy unique positions both scientifically and programmatically on the road to the exploration of the solar system. Japan Aerospace Exploration Agency (JAXA) plans a Phobos sample return mis...
-
Chapter
RNA Synthesis Before the Origin of Life
Since RNA possesses both genetic information and catalytic abilities, it is a potential biopolymer that is thought to support primordial life before the present DNA-protein system. There were multiple sources ...
-
Article
Racemization of Valine by Impact-Induced Heating
Homochirality plays an important role in all living organisms but its origin remains unclear. It also remains unclear whether such chiral molecules survived terrestrial heavy impact events. Impacts of extrater...
-
Article
Open AccessTemperature-induced oligomerization of polycyclic aromatic hydrocarbons at ambient and high pressures
Temperature-induced oligomerization of polycyclic aromatic hydrocarbons (PAHs) was found at 500–773 K and ambient and high (3.5 GPa) pressures. The most intensive oligomerization at 1 bar and 3.5 GPa occurs at...
-
Article
Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine
The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the am...
-
Article
Morphological changes of olivine grains reacted with amino acid solutions by impact process
Early oceans on Earth might have contained certain amounts of biomolecules such as amino acids, and they were subjected to meteorite impacts, especially during the late heavy bombardment. We performed shock re...
-
Article
Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses
Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in...
