A5046158719- Planetary Science and Exploration
- Spaceflight effects on biology
- Astro and Planetary Science
- Space Science and Extraterrestrial Life
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Polar Research and Ecology
- Aerospace Engineering and Energy Systems
- Protist diversity and phylogeny
- Space exploration and regulation
- Porphyrin Metabolism and Disorders
- Biochemical and Molecular Research
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Gout, Hyperuricemia, Uric Acid
- Geology and Paleoclimatology Research
- Chemical Reactions and Isotopes
- Genomics and Phylogenetic Studies
- Marine and Coastal Research
- Isotope Analysis in Ecology
- Medical Imaging Techniques and Applications
- Biosensors and Analytical Detection
- Cancer, Hypoxia, and Metabolism
- Electrical and Bioimpedance Tomography
- Space Satellite Systems and Control
Tokyo University of Pharmacy and Life Sciences
2011-2021
Chiba Institute of Technology
2019-2020
Nippon Medical School
2005-2019
Japan Aerospace Exploration Agency
2015-2016
Institute of Space and Astronautical Science
2015-2016
University Health Network
2010
University of Toronto
2010
Cancer Research Institute
2010
Mammalian xanthine dehydrogenase can be converted to oxidase by modification of cysteine residues or proteolysis the enzyme polypeptide chain. Here we present evidence that Cys535 and Cys992 rat liver are indeed involved in rapid conversion from oxidase. The purified mutants C535A and/or C992R were significantly resistant incubation with 4,4′-dithiodipyridine, whereas recombinant wild-type readily type, indicating these responsible for conversion. C535A/C992R mutant, however, very slowly...
The space environment is regularly used for experiments addressing astrobiology research goals. specific conditions prevailing in Earth orbit and beyond, notably the radiative (photons energetic particles) possibility to conduct long-duration measurements, have been main motivations developing experimental concepts expose chemical or biological samples outer space, use reentry of a spacecraft on simulate fall meteorite. This paper represents an overview past current conducted with special...
The hypothesis called "panspermia" proposes an interplanetary transfer of life. Experiments have exposed extremophilic organisms to outer space test microbe survivability and the panspermia hypothesis. Microbes inside shielding material with sufficient thickness protect them from UV-irradiation can survive in space. This process has been "lithopanspermia," meaning rocky panspermia. We previously proposed sub-millimeter cell pellets (aggregates) could harsh environment based on on-ground...
The extraordinarily resistant bacterium Deinococcus radiodurans withstands harsh environmental conditions present in outer space. was exposed for 1 year outside the International Space Station within Tanpopo orbital mission to investigate microbial survival and space travel. In addition, a ground-based simulation experiment with conditions, mirroring those from low Earth orbit, performed.We monitored cells during early stage of recovery after orbit exposure using electron microscopy tools....
The Tanpopo mission has two objectives: (1) test the panspermia hypothesis and (2) whether organic compounds may have been transferred to Earth before origin of life. We developed an exposure panel (EP) designed expose microbes space environment a capture high-velocity particles on International Space Station (ISS) using aerogel contained in aluminum container. panels returned after 1 year at Exposure Facility Japan Experimental Module, ISS. In this communication, we report measurements...
Two contradictory models have been proposed for the binding mode of substrate xanthine to and its activation mechanism by oxidoreductase. In an effort distinguish between two models, we determined crystal structures urate complexes demolybdo-form D428A mutant rat oxidoreductase at 1.7 Å reduced bovine milk enzyme 2.1 Å, latter representing a reaction intermediate. The results clearly indicate catalytically relevant xanthine.
Mammalian xanthine oxidoreductase can exist in both dehydrogenase and oxidase forms. Conversion between the two is implicated such diverse processes as lactation, anti‐bacterial activity, reperfusion injury a growing number of diseases. We have constructed variant rat liver enzyme that lacks carboxy‐terminal amino acids 1316–1331; it appears to assume an intermediate form, exhibiting mixture activities. The purified protein retained ~ 50–70% activity even after prolonged dithiothreitol...
The Tanpopo mission will address fundamental questions on the origin of terrestrial life. main goal is to test panspermia hypothesis. Panspermia a long-standing hypothesis suggesting interplanetary transport microbes. Another possible organic compounds carried from space by micrometeorites before To investigate and compounds, we performed experiments at Exposed Facility (EF) Japanese Experiment Module (JEM) International Space Station (ISS). was named Tanpopo, which in means dandelion. We...
The multiple extremes resistant bacterium Deinococcus radiodurans is able to withstand harsh conditions of simulated outer space environment. Tanpopo orbital mission performs a long-term exposure D. aiming investigate the possibility interplanetary transfer life. revealing molecular machinery responsible for survivability in environment can improve our understanding underlying stress response mechanisms. In this paper, we have evaluated after space-related UVC irradiation and vacuum....
The polyextremophile, gram-positive bacterium Deinococcus radiodurans can withstand harsh conditions of real and simulated outer space environment, e.g., UV ionizing radiation. A long-term exposure D. has been performed in Low Earth Orbit (LEO) frames the Tanpopo orbital mission aiming to investigate possibility interplanetary life transfer. Space vacuum (10−4–10−7 Pa) is a harmful factor, which induces dehydration affects microbial integrity, severely damaging cellular components: lipids,...
Abstract Regarding future space exploration missions and long-term exposure experiments, a detailed investigation of all factors present in the outer environment their effects on organisms life kingdoms is advantageous. Influenced by multiple space, extremophilic bacterium Deinococcus radiodurans has been long-termly exposed outside International Space Station frames Tanpopo orbital mission. The study presented here aims to elucidate molecular key components D. , which are responsible for...
p-Hydroxybenzoate hydroxylase (PHBH) is a flavoprotein monooxygenase that catalyzes the hydroxylation of p-hydroxybenzoate (p-OHB) to 3,4-dihydroxybenzoate (3,4-DOHB). PHBH can bind other benzoate derivatives in addition p-OHB; however, does not occur on 3,4-DOHB. Replacement Tyr385 with Phe forms mutant, which enables production 3,4,5-trihydroxybenzonate (gallic acid) from 3,4-DOHB, although catalytic activity mutant quite low. In this study, we report how L199V/Y385F double exhibits for...
Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on International Space Station. Glass particles a simulated 30 \mu m in diameter 2.4 g/cm^3 density were successfully captured by novel aerogel at velocity of 6 km/s. Background levels contaminated DNA lower than detection limit polymerase chain reaction assay. These results show that manufactured has good performance...
We are developing a silica-aerogel-based cosmic dust collector for use in the Tanpopo experiment to be conducted on International Space Station. The mass production of simple two-layer hydrophobic aerogels was undertaken contamination-controlled environment, yielding more than 100 undamaged products. collector, comprising an aerogel tile and holder panel, designed resist launch vibration conform exposure attachment. To this end, box-framing with inner outer densities 0.01 0.03 g/cm3,...
The Tanpopo mission is an astrobiology space experiment at the Japanese Experiment Module (JEM) 'Kibo' on International Space Station (ISS). One of sub-divided themes for intact capture organic bearing micrometeoroids in low Earth orbit using ultralow density silica aerogel (0.01 g/cm3). In order to evaluate damage matter during hyper velocity impacts into aerogel, Murchison meteorite powdered samples, analogs micrometeoroids, were fired flight-grade g/cm3) a two-stage light-gas gun with...
To investigate microbial viability and DNA damage, dried cell pellets of the radiation-resistant bacterium Deinococcus radiodurans were exposed to various space environmental conditions at Exposure Facility International Space Station (ISS) as part Tanpopo mission. Mutation analysis was done by sequencing rpoB gene encoding RNA polymerase β-subunit rifampicin-resistant mutants. Samples included bacteria environment with without exposure UV radiation well control samples held in ISS cabin...
Deinococcus aerius strain TR0125 is a bacterium isolated from the high atmosphere above Japan that shows strong resistance to desiccation, UV-C, and gamma radiation. Here, we report draft genome sequence of D. (4.5 Mb), which may provide useful genetic information supporting its biochemical features.