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排序方式: 共有222条查询结果,搜索用时 15 毫秒
1.
Sean R. Tachibana Longteng Tang Liangdong Zhu Yuka Takeda Keiji Fushimi Yoshibumi Ueda Takahiro Nakajima Yuto Kuwasaki Moritoshi Sato Rei Narikawa Chong Fang 《International journal of molecular sciences》2021,22(10)
Cyanobacteriochromes (CBCRs) are promising optogenetic tools for their diverse absorption properties with a single compact cofactor-binding domain. We previously uncovered the ultrafast reversible photoswitching dynamics of a red/green photoreceptor AnPixJg2, which binds phycocyanobilin (PCB) that is unavailable in mammalian cells. Biliverdin (BV) is a mammalian cofactor with a similar structure to PCB but exhibits redder absorption. To improve the AnPixJg2 feasibility in mammalian applications, AnPixJg2_BV4 with only four mutations has been engineered to incorporate BV. Herein, we implemented femtosecond transient absorption (fs-TA) and ground state femtosecond stimulated Raman spectroscopy (GS-FSRS) to uncover transient electronic dynamics on molecular time scales and key structural motions responsible for the photoconversion of AnPixJg2_BV4 with PCB (Bpcb) and BV (Bbv) cofactors in comparison with the parent AnPixJg2 (Apcb). Bpcb adopts the same photoconversion scheme as Apcb, while BV4 mutations create a less bulky environment around the cofactor D ring that promotes a faster twist. The engineered Bbv employs a reversible clockwise/counterclockwise photoswitching that requires a two-step twist on ~5 and 35 picosecond (ps) time scales. The primary forward Pfr → Po transition displays equal amplitude weights between the two processes before reaching a conical intersection. In contrast, the primary reverse Po → Pfr transition shows a 2:1 weight ratio of the ~35 ps over 5 ps component, implying notable changes to the D-ring-twisting pathway. Moreover, we performed pre-resonance GS-FSRS and quantum calculations to identify the Bbv vibrational marker bands at ~659,797, and 1225 cm−1. These modes reveal a stronger H-bonding network around the BV cofactor A ring with BV4 mutations, corroborating the D-ring-dominant reversible photoswitching pathway in the excited state. Implementation of BV4 mutations in other PCB-binding GAF domains like AnPixJg4, AM1_1870g3, and NpF2164g5 could promote similar efficient reversible photoswitching for more directional bioimaging and optogenetic applications, and inspire other bioengineering advances. 相似文献
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Yuka Tsuji Mizuki Kuramochi Hossain M. Golbar Takeshi Izawa Mitsuru Kuwamura Jyoji Yamate 《International journal of molecular sciences》2020,21(23)
Overdose of acetaminophen (APAP), an antipyretic drug, is an important cause of liver injury. However, the mechanism in the rat model remains undetermined. We analyzed APAP-induced hepatotoxicity using rats based on M1/M2-macrophage functions in relation to damage-associated molecular patterns (DAMPs) and autophagy. Liver samples from six-week-old rats injected with APAP (1000 mg/kg BW, ip, once) after 15 h fasting were collected at hour 10, and on days 1, 2, 3, and 5. Liver lesions consisting of coagulation necrosis and inflammation were seen in the affected centrilobular area on days 1 and 2, and then, recovered with reparative fibrosis by day 5. Liver exudative enzymes increased transiently on day 1. CD68+ M1-macrophages increased significantly on days 1 and 2 with increased mRNAs of M1-related cytokines such as IFN-γ and TNF-α, whereas CD163+ M2-macrophages appeared later on days 2 and 3. Macrophages reacting to MHC class II and Iba1 showed M1-type polarization, and CD204+ macrophages tended to be polarized toward M2-type. At hour 10, interestingly, HMGB1 (representative DAMPs) and its related signals, TLR-9 and MyD88, as well as LC3B+ autophagosomes began to increase. Collectively, the pathogenesis of rat APAP hepatotoxicity, which is the first, detailed report for a rat model, might be influenced by macrophage functions of M1 type for tissue injury/inflammation and M2-type for anti-inflammatory/fibrosis; particularly, M1-type may function in relation to DAMPs and autophagy. Understanding the interplayed mechanisms would provide new insight into hepato-pathogenesis and contribute to the possible development of therapeutic strategies. 相似文献
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Yoshimune Nonomura Taku Miura Takaaki Miyashita Yuka Asao Hirokazu Shirado Yasutoshi Makino Takashi Maeno 《Journal of the Royal Society Interface》2012,9(71):1216-1223
Water detection is one of the most crucial psychological processes for many animals. However, nobody knows the perception mechanism of water through our tactile sense. In the present study, we found that a characteristic frictional stimulus with large acceleration is one of the cues to differentiate water from water contaminated with thickener. When subjects applied small amounts of water to a glass plate, strong stick-slip phenomena with a friction force of 0.46 ± 0.30 N and a vertical force of 0.57 ± 0.36 N were observed at the skin surface, as shown in previous studies. Surprisingly, periodic shears with acceleration seven times greater than gravitational acceleration occurred during the application process. Finite-element analyses predicted that these strong stimuli could activate tactile receptors: Meissner''s corpuscle and Pacinians. When such stimuli were applied to the fingertips by an ultrasonic vibrator, a water-like tactile texture was perceived by some subjects, even though no liquid was present between the fingertip and the vibrator surface. These findings could potentially be applied in the following areas: materials science, information technology, medical treatment and entertainment. 相似文献
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Hiromi Yoshida Yuka Tomiyama Masayuki Saiki Yoshiyuki Mizushina 《Journal of the American Oil Chemists' Society》2007,84(11):1031-1038
The positional distribution of fatty acids (FA) of triacylglycerols (TAG) and major phospholipids (PL) prepared from four
cultivars of peas (Pisum sativum L.) were investigated as well as their tocopherol contents. The lipids extracted from these peas were separated by thin-layer
chromatography (TLC) into seven fractions. The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while the
other components were also present in minor proportions (5.6–9.2%). γ-Tocopherol was present in the highest concentration,
and α- and δ-tocopherols were very small amounts. The main PL components isolated from the four cultivars were phosphatidylcholine
(42.3–49.2%), followed by phosphatidylinositol (23.3–25.2%) and then phosphatidylethanolamine (17.7–20.5%). Small but significant
differences (P < 0.05) in FA distribution existed when different pea cultivars were determined. However, the principal characteristics of
the FA distribution in the TAG and the three PL were evident among the four cultivars; unsaturated FA were predominantly located
in the sn-2 position, and saturated FA primary occupied the sn-1 or sn-3 position in the oils of the peas. These results suggest that the regional distribution of tocopherols and fatty acids in
peas is not dependent on the climatic conditions and the soil characteristics of the cultivation areas during the growing
season. 相似文献
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Hiromi Yoshida Takaaki Tanigawa Naoko Yoshida Isoko Kuriyama Yuka Tomiyama Yoshiyuki Mizushina 《Food chemistry》2011
Endogenous tocochromanols in extracted lipids from rice brans of the five cultivars were determined by high-performance liquid chromatography, and were investigated in relation to the fatty acid (FA) distribution of triacylglycerols (TAG) and phospholipids (PL). The dominant tocols were α-tocopherol and γ-tocotrienol, followed by α-tocotrienol and with much smaller amounts of γ-tocopherol and δ-tocotrienol. The lipids of these rice brans comprised mainly TAG (80.6–86.0 wt.%), free FA (4.2–9.0 wt.%), and phospholipids (5.5–6.7 wt.%), whilst other components were also detected in minor proportions (0.2–2.1 wt.%). The PL components included phosphatidyl choline (31.8–46.8 wt.%), phosphatidyl ethanolamine (25.0–38.9 wt.%) and phosphatidyl inositol (20.2–23.2 wt.%). Comparison of these different cultivars showed, with a few exceptions, no significant differences (P > 0.05) in FA distribution. FA distribution of TAG among the five cultivars was evident in the rice brans: unsaturated FA were predominantly concentrated at the sn-2 position and saturated FA primarily occupying the sn-1 or sn-3 position. These results suggest that the tocopherol content, lipid component, and FA distribution in rice brans are not dependent on the cultivation areas during the growing season. 相似文献
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