129 research outputs found
A Note on the Over−valuation of the US Dollar
I examine the frameworks of analyzing this problem, referring to some representative papers, and point out that information on the real (as opposed to monetary) economies plays a surprisingly large role.米ドルの過大評価の問題は,同国の経常収支赤字とのかねあいで,以前からかなりの関心を引いてきた。この研究ノートは,比較的新しい文献をいくつか参照しながら,本問題についての分析枠組みを筆者なりに整理するものである。問題の所在,すなわち過大評価の大きさと,その是正のための調整コストにかんしては,やや古いが,Bergsten and Williamson 編の二冊がまとまっている。なお最近,筆者は未見の(参考文献にも挙げない)新著が,同じ編者によって発刊されているはずである。以下で参照する論文も,多くはサーベイ的な叙述を含んでいるから,ここであえて問題そのものを紹介する必要はないであろう
H3K9 Demethylases JMJD1A and JMJD1B Control Prospermatogonia to Spermatogonia Transition in Mouse Germline
Histone H3 lysine 9 (H3K9) methylation is dynamically regulated by methyltransferases and demethylases. In spermatogenesis, prospermatogonia differentiate into differentiating or undifferentiated spermatogonia after birth. However, the epigenetic regulation of prospermatogonia to spermatogonia transition is largely unknown. We found that perinatal prospermatogonia have extremely low levels of di-methylated H3K9 (H3K9me2) and that H3K9 demethylases, JMJD1A and JMJD1B, catalyze H3K9me2 demethylation in perinatal prospermatogonia. Depletion of JMJD1A and JMJD1B in the embryonic germline resulted in complete loss of male germ cells after puberty, indicating that H3K9me2 demethylation is essential for male germline maintenance. JMJD1A/JMJD1B-depleted germ cells were unable to differentiate into functional spermatogonia. JMJD1 isozymes contributed to activation of several spermatogonial stem cell maintenance genes through H3K9 demethylation during the prospermatogonia to spermatogonia transition, which we propose is key for spermatogonia development. In summary, JMJD1A/JMJD1B-mediated H3K9me2 demethylation promotes prospermatogonia to differentiate into functional spermatogonia by establishing proper gene expression profiles
Plasmapheresis for Spur Cell Anemia
A 45-year-old male patient with spur cell anemia was treated by plasmapheresis. At first, a membrane plasma separator was employed six times successively to try to prevent the progressive anemia. No significant improvement was achieved with respect to hematological parameters of hemolysis. A discontinuous flow centrifuge was then used four times consecutively. The spur cell count decreased and the progression of the anemia was transiently interrupted after every plasmapheresis of this type. Sequential measurements of the free cholesterol/phospholipid (FC/PL) molar ratio of the red cell membrane lipid revealed the importance of a plasma factor for spur cell formation. It showed that abnormal changes in FC/PL ratio of the red cell membrane were entirely dependent on a precursory change in the lipid composition of the patient\u27s plasma. Although, to our knowledge, plasmapheresis to treat spur cell anemia has not yet been recorded in the literature, in our experience, this therapeutic measure is recommendable for patients with spur cell anemia unresponsive to other forms of treatment
Combined Loss of JMJD1A and JMJD1B Reveals Critical Roles for H3K9 Demethylation in the Maintenance of Embryonic Stem Cells and Early Embryogenesis
Histone H3 lysine 9 (H3K9) methylation is unevenly distributed in mammalian chromosomes. However, the molecular mechanism controlling the uneven distribution and its biological significance remain to be elucidated. Here, we show that JMJD1A and JMJD1B preferentially target H3K9 demethylation of gene-dense regions of chromosomes, thereby establishing an H3K9 hypomethylation state in euchromatin. JMJD1A/JMJD1B-deficient embryos died soon after implantation accompanying epiblast cell death. Furthermore, combined loss of JMJD1A and JMJD1B caused perturbed expression of metabolic genes and rapid cell death in embryonic stem cells (ESCs). These results indicate that JMJD1A/JMJD1B-meditated H3K9 demethylation has critical roles for early embryogenesis and ESC maintenance. Finally, genetic rescue experiments clarified that H3K9 overmethylation by G9A was the cause of the cell death and perturbed gene expression of JMJD1A/JMJD1B-depleted ESCs. We summarized that JMJD1A and JMJD1B, in combination, ensure early embryogenesis and ESC viability by establishing the correct H3K9 methylated epigenome
C9orf72-derived arginine-rich poly-dipeptides impede phase modifiers
Nuclear import receptors (NIRs) not only transport RNA-binding proteins (RBPs) but also modify phase transitions of RBPs by recognizing nuclear localization signals (NLSs). Toxic arginine-rich poly-dipeptides from C9orf72 interact with NIRs and cause nucleocytoplasmic transport deficit. However, the molecular basis for the toxicity of arginine-rich poly-dipeptides toward NIRs function as phase modifiers of RBPs remains unidentified. Here we show that arginine-rich poly-dipeptides impede the ability of NIRs to modify phase transitions of RBPs. Isothermal titration calorimetry and size-exclusion chromatography revealed that proline:arginine (PR) poly-dipeptides tightly bind karyopherin-β2 (Kapβ2) at 1:1 ratio. The nuclear magnetic resonances of Kapβ2 perturbed by PR poly-dipeptides partially overlapped with those perturbed by the designed NLS peptide, suggesting that PR poly-dipeptides target the NLS binding site of Kapβ2. The findings offer mechanistic insights into how phase transitions of RBPs are disabled in C9orf72-related neurodegeneration
The Japanese space gravitational wave antenna; DECIGO
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future
Japanese space gravitational wave antenna. DECIGO is expected to open a new window of
observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing
various mysteries of the universe such as dark energy, formation mechanism of supermassive
black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of
three drag-free spacecraft, whose relative displacements are measured by a differential Fabry–
Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre-
DECIGO first and finally DECIGO in 2024
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