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result(s) for
"Terada, Naoki"
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Impact-induced amino acid formation on Hadean Earth and Noachian Mars
2020
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 discharge, impact shock, and hydrothermal heating), from reduced compounds that may have been limited in their availabilities on Hadean Earth and Noachian Mars. On the other hand, formation of amino-acids and nucleobases from CO
2
and N
2
(i.e., the most abundant C and N sources on Earth during the Hadean) has been limited via spark discharge. Here, we demonstrate the synthesis of amino acids by laboratory impact-induced reactions among simple inorganic mixtures: Fe, Ni, Mg
2
SiO
4
, H
2
O, CO
2
, and N
2
, by coupling the reduction of CO
2
, N
2
, and H
2
O with the oxidation of metallic Fe and Ni. These chemical processes simulated the possible reactions at impacts of Fe-bearing meteorites/asteroids on oceans with a CO
2
and N
2
atmosphere. The results indicate that hypervelocity impact was a source of amino acids on the Earth during the Hadean and potentially on Mars during the Noachian. Amino acids formed during such events could more readily polymerize in the next step of the chemical evolution, as impact events locally form amino acids at the impact sites.
Journal Article
Patient-derived xenografts as in vivo models for research in urological malignancies
by
Ogawa, Osamu
,
Terada, Naoki
,
Inoue, Takahiro
in
631/154/1435
,
631/61/212/2166
,
692/699/67/589
2017
Key Points
Lack of appropriate models that recapitulate the complexity and heterogeneity of urological tumours precludes most of the preclinical reagents that enter clinical trials from achieving regulatory approval
Patient-derived xenograft (PDX) models are characterized by direct engraftment of patient-derived tumour fragments into immunocompromised mice, improving preservation of the identity of the original tumours
Use of urological tumour PDX models for analysing tumour biology and, more importantly, in drug development has increased
Several agents targeting immune systems have shown promising results in kidney and bladder cancer, but they require PDX models established in mice with an intact immune system to trigger an immune response to the tumour
International collaboration for sharing PDX models is a requisite for improving patient outcomes.
Patient-derived xenograft (PDX) models can maintain the original histology and the molecular and genetic characteristics of the source tumour. Thus, PDX models have advantages over conventional models for drug development and treatment decisions in personalized medicine. In this Review, the authors discuss the potential of PDX models for both basic and clinical urological research.
Lack of appropriate models that recapitulate the complexity and heterogeneity of urological tumours precludes most of the preclinical reagents that target urological tumours from receiving regulatory approval. Patient-derived xenograft (PDX) models are characterized by direct engraftment of patient-derived tumour fragments into immunocompromised mice. PDXs can maintain the original histology, as well as the molecular and genetic characteristics of the source tumour. Thus, PDX models have various advantages over conventional cell-line-derived xenograft (CDX) and other models, which has resulted in an increase in the use of urological tumour PDXs in the analysis of tumour biology and, importantly, for drug development and treatment decisions in personalized medicine. PDX models of urological malignancies have great potential to be used for both basic and clinical research, but limitations exist and need to be overcome. In particular, several agents targeting the immune system have shown promising results in kidney and bladder cancer; however, establishing PDX models in mice with an intact immune system so that an immune response against the tumour is triggered is important to investigate these new therapeutics. Moreover, international collaboration to share PDX models is essential for research concerning fatal urological tumours.
Journal Article
Suppression of hydrodynamic escape of an H2-rich early Earth atmosphere by radiative cooling of carbon oxides
2024
Radiative cooling by molecules is a crucial process for hydrodynamic escape, as it can efficiently remove the thermal energy driving the outflow, acquired through X-ray and extreme UV absorption. Carbon oxides, such as CO and CO2, and their photochemical products are anticipated to serve as vital radiative cooling sources not only in atmospheres dominated by carbon oxides but also in H2-rich atmospheres. However, their specific effects on the hydrodynamic escape, especially in H2-rich atmospheres, have been inadequately investigated. In this study, we conduct 1-D hydrodynamic escape simulations for H2-rich atmospheres incorporating CO, CO2, and their chemical products on an Earth-mass planet. We consider detailed radiative cooling processes and chemical networks related to carbon oxides to elucidate their impacts on the hydrodynamic escape. In the escape outflow, CO2 undergoes rapid photolysis, producing CO and atomic oxygen, while CO exhibits photochemical stability compared to CO2. The H2 oxidation by atomic oxygen results in the production of OH and H2O. Consequently, the hydrodynamic escape is significantly suppressed by the radiative cooling effects of CO, H2O, OH, and H3+ even when the basal mixing fraction of CO and CO2 is lower than ~ 0.01. These mechanisms extend the lifetime of H2-rich atmospheres by about one order of magnitude compared to the case of pure hydrogen atmospheres on early Earth, which also results in negligible escape of heavier carbon- and nitrogen-bearing molecules and noble gases.
Journal Article
Prognostic and predictive biomarkers in prostate cancer: latest evidence and clinical implications
by
Ogawa, Osamu
,
Terada, Naoki
,
Akamatsu, Shusuke
in
Androgen receptors
,
Biomarkers
,
Cancer therapies
2017
Advances in our understanding of the mechanisms driving castration-resistant prostate cancer have promoted the development of several new drugs including androgen receptor-directed therapy and chemotherapy. Concomitant docetaxel treatment at the beginning of hormonal therapy for metastatic prostate cancer has resulted in longer overall survival than with hormonal therapy alone. Elucidating an appropriate treatment sequence using these therapies is important for maximizing clinical benefit in castration-sensitive and castration-resistant prostate cancer patients. The development of advanced high-throughput ‘omics’ technology has enabled the use of novel markers to guide prognosis and treatment of this disease. In this review, we outline the genomic landscape of prostate cancer and the molecular mechanisms of castration-resistant progression, and how these affect the development of new drugs, and their clinical implications for selecting treatment sequence. We also discuss many of the potential tissue-based or liquid biomarkers that may soon enter clinical use, with the hope that several of these prognostic or predictive markers will guide precision medicine for prostate cancer patients in the near future.
Journal Article
Alleviating Salt Stress in Tomatoes through Seed Priming with Polyethylene Glycol and Sodium Chloride Combination
by
Habibi, Nasratullah
,
Terada, Naoki
,
Sanada, Atsushi
in
growth
,
photosynthesis
,
Polyethylene glycol
2024
Tomato cultivation grapples with salt stress, disrupting growth parameters and physiological processes. High salinity levels induce osmotic stress, impacting cellular integrity and hindering metabolic activities. Salt accumulation at the root zone alters key physiological attributes, compromising overall harvestable output. Seed priming emerges as a potential solution to enhance plant resilience. A research gap exists in understanding the combined influence of polyethylene glycol and sodium chloride as seed priming agents under salt stress conditions. The study occurred in the Greenhouse of Laboratory Horticultural Science at Tokyo University of Agriculture. Micro Tom seeds underwent a factorial randomized design, involving five salinity and four priming treatments. Replicated ten times, totaling 200 plants, seed priming used polyethylene glycol, inducing salinity stress with sodium chloride. Meticulous measurements of growth parameters, photosynthetic traits, yield attributes, and electrolyte leakage were conducted. Statistical analyses discerned treatment effects at a 5% significance level. Seed priming, especially with ‘PEG plus NaCl’, effectively mitigated salt stress effects on tomato plants. Under severe salt stress, primed plants exhibited increased plant height, trusses, leaves, and leaf area. Photosynthetic efficiency and yield attributes demonstrated significant improvements with seed priming. Electrolyte leakage, indicative of leaf damage, was notably reduced by seed priming treatments, with ‘PEG plus NaCl’ exhibiting the highest efficacy. These results offer valuable guidance for optimizing agricultural practices in saline environments, contributing to sustainable strategies for food security amidst escalating environmental challenges.
Journal Article
In situ observations of ions and magnetic field around Phobos: the mass spectrum analyzer (MSA) for the Martian Moons eXploration (MMX) mission
2021
The mass spectrum analyzer (MSA) will perform in situ observations of ions and magnetic fields around Phobos as part of the Martian Moons eXploration (MMX) mission to investigate the origin of the Martian moons and physical processes in the Martian environment. MSA consists of an ion energy mass spectrometer and two magnetometers which will measure velocity distribution functions and mass/charge distributions of low-energy ions and magnetic field vectors, respectively. For the MMX scientific objectives, MSA will observe solar wind ions, those scattered at the Phobos surface, water-related ions generated in the predicted Martian gas torus, secondary ions sputtered from Phobos, and escaping ions from the Martian atmosphere, while monitoring the surrounding magnetic field. MSA will be developed from previous instruments for space plasma missions such as Kaguya, Arase, and BepiColombo/Mio to contribute to the MMX scientific objectives.
Journal Article
Atmospheric formaldehyde production on early Mars leading to a potential formation of bio-important molecules
by
Koyama, Shungo
,
Kamada, Arihiro
,
Vandaele, Ann Carine
in
704/445/3929
,
704/445/824
,
Amino acids
2024
Formaldehyde (H
2
CO) 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 evidence on Mars indicates a temperate environment compatible with the existence of surface liquid water during its early history at 3.8–3.6 billion years ago (Ga), which was maintained by the warming effect of reducing gases, such as H
2
. However, it remains uncertain whether such a temperate and weakly reducing surface environment on early Mars was suitable for producing H
2
CO. In this study, we investigated the atmospheric production of H
2
CO on early Mars using a 1-D photochemical model assuming a thick CO
2
-dominated atmosphere with H
2
and CO. Our results show that a continuous supply of atmospheric H
2
CO can be used to form various organic compounds, including amino acids and sugars. This could be a possible origin for the organic matter observed on the Martian surface. Given the previously reported conversion rate from H
2
CO into ribose, the calculated H
2
CO deposition flux suggests a continuous supply of bio-important sugars on early Mars, particularly during the Noachian and early Hesperian periods.
Journal Article
Exogenous Application of Glycine Betaine to Passiflora edulis Sims f. flavicarpa to Mitigate Drought Stress on Two Propagation Methods
by
Sanada, Atsushi
,
Oliveira, Leonardo de Almeida
,
Nguyen, Nga Thi Thu
in
Abiotic stress
,
Adaptation
,
Agricultural production
2025
Glycine betaine (GB) is a compatible solute that enhances plant tolerance to abiotic stresses, yet its role in fruit crops remains insufficiently explored. This study assessed whether GB improves drought tolerance in Passiflora edulis Sims f. flavicarpa, a crop sensitive to irregular rainfall. A 3 × 2 × 2 factorial design was employed, combining three drought levels (control, mild, and severe), two propagation methods (seedlings and cuttings), and two GB treatments (0 and 100 mM), with 60 plants and five replicates. Plants were grown under controlled conditions, and irrigation was adjusted to maintain target field capacities. Chlorophyll content was monitored daily, and agronomic and physiological traits were measured after 45 days. GB application influenced leaf water dynamics and stress responses. Cuttings generally showed clearer improvements in drought tolerance when treated with GB, while seedlings exhibited more variable outcomes. These differences appear linked to the propagation method and developmental stage as cuttings were at a more advanced phase, whereas seedlings remained vegetative. Overall, the results demonstrate that exogenous GB can enhance drought tolerance in passion fruit, although its effectiveness is propagation-dependent and context-specific, highlighting the need to tailor its application to cultivation practices.
Journal Article
Stable carbon isotope evolution of formaldehyde on early Mars
2024
Organic matter in the Martian sediments may provide a key to understanding the prebiotic chemistry and habitability of early Mars. The Curiosity rover has measured highly variable and
13
C-depleted carbon isotopic values in early Martian organic matter whose origin is uncertain. One hypothesis suggests the deposition of simple organic molecules generated from
13
C-depleted CO derived from CO
2
photochemical reduction in the atmosphere. Here, we present a coupled photochemistry-climate evolution model incorporating carbon isotope fractionation processes induced by CO
2
photolysis, carbon escape, and volcanic outgassing in an early Martian atmosphere of 0.5–2 bar, composed mainly of CO
2
, CO, and H
2
to track the evolution of the carbon isotopic composition of C-bearing species. The calculated carbon isotopic ratio in formaldehyde (H
2
CO) can be highly depleted in
13
C due to CO
2
-photolysis-induced fractionation and is variable with changes in atmospheric CO/CO
2
ratio, surface pressure, albedo, and H
2
outgassing rate. Conversely, CO
2
becomes enriched in
13
C, as estimated from the carbonates preserved in ALH84001 meteorite. Complex organic matter formed by the polymerization of such H
2
CO could explain the strong depletion in
13
C observed in the Martian organic matter. Mixing with other sources of organic matter would account for its unique variable carbon isotopic values.
Journal Article
Dysregulation of Type II Transmembrane Serine Proteases and Ligand-Dependent Activation of MET in Urological Cancers
2020
Unlike in normal epithelium, dysregulated overactivation of various proteases have been reported in cancers. Degradation of pericancerous extracellular matrix leading to cancer cell invasion by matrix metalloproteases is well known evidence. On the other hand, several cell-surface proteases, including type II transmembrane serine proteases (TTSPs), also induce progression through activation of growth factors, protease activating receptors and other proteases. Hepatocyte growth factor (HGF) known as a multifunctional growth factor that upregulates cancer cell motility, invasiveness, proliferative, and anti-apoptotic activities through phosphorylation of MET (a specific receptor of HGF). HGF secreted as inactive zymogen (pro-HGF) from cancer associated stromal fibroblasts, and the proteolytic activation by several TTSPs including matriptase and hepsin is required. The activation is strictly regulated by HGF activator inhibitors (HAIs) in physiological condition. However, downregulation is frequently observed in cancers. Indeed, overactivation of MET by upregulation of matriptase and hepsin accompanied by the downregulation of HAIs in urological cancers (prostate cancer, renal cell carcinoma, and bladder cancer) are also reported, a phenomenon observed in cancer cells with malignant phenotype, and correlated with poor prognosis. In this review, we summarized current reports focusing on TTSPs, HAIs, and MET signaling axis in urological cancers.
Journal Article