A paleo-environmental study in JARE Phase X - Deep ice coring in the Dome Fuji area for “Oldest Ice Core”-

The Tenth Symposium on Polar Science/Special session: [S] Future plan of Antarctic research: Towards phase X of the Japanese Antarctic Research Project (2022-2028) and beyond, Tue. 3 Dec. / 2F Auditorium, National Institute of Polar Researc

キイロショウジョウバエ由来のチオレドキシン還元酵素のC未端テトラペプチド配列は、ヒト肺由来のチオレドキシン還元酵素では酸化還元活性を示さない

The isozymes of mammalian thioredoxin reductase (TrxR) contain the penultimate selenocysteineresidue (SeCys) in the redox-active C-terminal tetrapeptide, -Gly-Cys-SeCys-Gly (end). Amutant form of the mammalian enzyme TrxR-X498C in which SeCys is replaced with Cys showsa dramatically decreased catalytic activity, suggesting that SeCys residue plays an integral role inthe catalysis. In contrast, TrxR of the fruit fly, Drosophila melanogaster, has no selenium in the corresponding C-terminal redox sequence, which instead of SeCys has flanking serine residues in the terminal sequence, -Ser-Cys-Cys-Ser (end). Because the catalytic activity of Dm-TrxR is comparable to that of the mammalian selenoenzyme, we introduced the serine residues at the corresponding positions of the recombinant TrxR-X498C and mimicked the redox center of the fruit fly TrxR. However, the catalysis remained as low as the Cys mutant of the selenoenzyme, suggesting that the additional structural features are still required for the tetrapeptide to function as a redox center. MOPAC calculation suggested that the complete motif might involve the hexapeptide sequence, which includes a proline residue, -Pro-X-Ser-Cys-Cys-Ser (end). The proline-containing motif is conserved among other insect TrxRs such as those of honeybee and fruit fly.ほ乳類チオレドキシン還元酵素はＣ末端配列-Gly-Cys-SeCys-Gly（end）の後ろから２番目にセレノシステイン（SeCys）残基を持つ．SeCys をシステインに変換すると酵素の活性は大きく低下するので，SeCys 残基が触媒活性に必須であることが分かる．これに対してキイロショウジョウバエのチオレドキシン還元酵素（Dm-TrxR）のＣ末端配列にはセレンが含まれず，システイン残基の対が２つのセリンに挟まれた配列-Ser-Cys-Cys-Ser (end）を持つ．それでも Dm-TrxR はほ乳類のセレン含有酵素と同程度の触媒能を示す．われわれはヒト肺チオレドキシン還元酵素に Dm-TrxR のＣ末端テトラペプチド配列を導入してその効果を調べた．しかし，酵素活性はまったく上昇せず，Dm-TrxR のＣ末端のテトラペプチド配列-Ser-Cys-Cys-Ser だけでは Cys 残基のチオール基を活性化する効果はなかった．そこで，分子軌道計算 MOPAC を用いて酸化還元機能を担うためのＣ末端配列モチーフを探索した．その結果，テトラペプチドにさらに２つ先のプロリンまでを含めた Pro-X-Ser-Cys-Cys-Ser（end）により初めて酸化還元モチーフとして機能する可能性が示唆された．Pro を含むこの配列モチーフはミツバチや蚊などほかの昆虫の TrxR でも保存されてい

Early Rehabilitation with Weight-bearing Standing-shaking-board Exercise in Combination with Electrical Muscle Stimulation after Anterior Cruciate Ligament Reconstruction

The objective of early rehabilitation after anterior cruciate ligament (ACL) reconstruction is to increase the muscle strength of the lower extremities. Closed kinetic chain (CKC) exercise induces co-contraction of the agonist and antagonist muscles. The purpose of this study was to compare the postoperative muscle strength/mass of subjects who performed our new CKC exercise (new rehabilitation group:group N) from week 4, and subjects who received traditional rehabilitation alone (traditional rehabilitation group:group T). The subjects stood on the device and maintained balance. Then, low-frequency stimulation waves were applied to 2 points each in the anterior and posterior region of the injured thigh 3 times a week for 3 months. Measurement of muscle strength was performed 4 times (before the start, and then once a month). Muscle mass was evaluated in CT images of the extensor and flexor muscles of 10 knees (10 subjects) in each group. The injured legs of group N showed significant improvement after one month compared to group T. The cross-sectional area of the extensor muscles of the injured legs tended to a show a greater increase at 3 months in group N. This rehabilitation method makes it possible to contract fast-twitch muscles, which may be a useful for improving extensor muscle strength after ACL reconstruction

Timing of climatic events for Termination II from O2/N2, d18Oatm and CH4 records of the Dome Fuji ice core, Antarctica

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Swelling Behavior of Polybutadiene Networks in Nematic Liquid Crystal Solvents (STATES AND STRUCTURES-Polymer Condensed States) .

Degree of equilibrium swelling (Q) of polybutadiene networks in four nematic liquid crystals (LCs) has been investigated as a function of temperature by cross-polarized microscopy. Phase behavior of the LCs in the networks has also been observed. It has been found that the nematic-to-isotropic phase transition temperatures of the LCs in the networks (TNI g) are slightly (ca. 1K) lower than the ones of the corresponding pure LCs (TNI o), and that the depression degrees of TNI in each system are comparable in spite of large differences in Q between every system. In the temperature regions of TNI g<T<TNI o where the LC phases inside and outside gel are different, Q is almost constant against temperature change