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71.
Shigeaki Nakazawa Kazunobu Sato Daisuke Shiomi M. Luisa T.M.B. Franco M. Celina R.L.R. Lazana M. Candida B.L. Shohoji Koichi Itoh Takeji Takui 《Inorganica chimica acta》2008,361(14-15):4031-4037
C60-based polyanionic high-spin clusters (S = 1–3) in their ground state have been prepared by successive chemical reductions of pristine C60 fullerene with potassium in the presence of dicyclohexano-18-crown-6-ether in solution. Intermolecular spin-triplet, quintet, and septet states arising from the C60-based polyanionic molecular clusters have been generated at ambient temperature and identified by CW-ESR and pulse-ESR-based two-dimensional (2D) electron spin transient nutation (2D-ESTN) spectroscopy in organic rigid glasses, for the first time. Intermolecular exchange interactions between mono- and polyanionic C60 fullerenes are ferromagnetic via bridging potassium metal cations. The molecular structures of the polyanionic high-spin C60 clusters in solution have been proposed by a well-established phenomenological spin Hamiltonian approach in terms of the D-tensor-based calculations for the high-spin clusters. The findings of the C60-based high-spin molecular clusters evidence the occurrence of an intramolecular triplet C60 dianion in the ground state. Unequivocal spin identification for molecular high-spin entities by 2D-ESTN spectroscopy and its powerfulness have been illustrated, emphasizing that the 2D-ESTN spectroscopy is useful for mixtures of molecular species with different spin multiplicities, characterized by a small g-anisotropy, for which the powerfulness of advanced high-frequency ESR spectroscopy is hampered. 相似文献
72.
Shigeaki Ito Shigeki Hamada Hiroyuki Ito Hirokazu Matsui Tadahiro Ozawa Hidenori Taguchi Susumu Ito 《Biotechnology letters》2009,31(7):1065-1071
The cellobiose 2-epimerase from Ruminococcus albus (RaCE) catalyzes the epimerization of cellobiose and lactose to 4-O-β-d-glucopyranosyl-d-mannose and 4-O-β-d-galactopyranosyl-d-mannose (epilactose). Based on the sequence alignment with N-acetyl-d-glucosamine 2-epimerases of known structure and on a homology-modeled structure of RaCE, we performed site-directed mutagenesis
of possible catalytic residues in the enzyme, and the mutants were expressed in Escherichia coli cells. We found that R52, H243, E246, W249, W304, E308, and H374 were absolutely required for the activity of RaCE. F114
and W303 also contributed to catalysis. These residues protruded into the active-site cleft in the model (α/α)6 core barrel structure. 相似文献
73.
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75.
Sugi (Cryptomeria japonica D. Don) is one of the most important evergreen coniferous plantation species in Japan. Much of the riparian forest that was
originally dominated by deciduous broadleaf trees has been converted into sugi plantations. The present study investigated
the seasonality of leaf-litter input and leaf dispersal to streams to assess the effects of converting riparian forest to
sugi plantations. The seasonality of leaf-litter input was assessed at three streams in Nagoya University Forest. At one stream
dominated by deciduous broadleaf trees, input was limited to autumn. At two streams in a sugi plantation, input was prolonged
from autumn to early spring, and was dominated by sugi needles from winter to early spring. These results suggest that sugi
plantations alter the seasonality of leaf-litter input from riparian forests and affect stream ecosystems. Leaf dispersal
was assessed by considering the relationship between leaf dispersal distance from three forest layers to the stream and leaf-litter
input into two streams. The maximum leaf dispersal distance was 26–28 m for deciduous broadleaf trees from mid-October to
November and 10–12 m for sugi needles from December to April. Leaf dispersal distance depended on the tree species. Four species
of deciduous broadleaf tree showed greater leaf dispersal than that of sugi. The mean weight of individual sugi needles was
higher than that of the broadleaf trees’ leaves, and dispersal depended on strong winds in winter and early spring. Although
the leaf dispersal distance from the understory was within 2–4 m, it could be a significant source of leaf-litter input to
streams. 相似文献
76.
Kanna Okayama Takeshi Honda Shigeaki Matsuda Tadashi Saito Masaya Kawase 《Current microbiology》2011,62(1):90-95
During our research into the pathogenesis of Vibrio parahaemolyticus, we noticed that the concentration of serum added to the tissue culture medium (Dulbecco’s modified Eagle’s medium: DMEM)
greatly affected its growth. Using gel filtration column chromatography, we clearly demonstrated that serum contains not only
a bacterial growth inhibitor (BGI) but also a bacterial growth enhancer (BGE) for Vibrio parahaemolyticus. Our data indicate that the BGI is transferrin, whereas the BGE seems to be an undescribed small molecule (molecular weight
of 1,000–3,000 Da) and is associated with magnesium and molybdenum ions. BGE activity was not decreased by heat treatment
(at 60 or 100°C for 30 min) and affected the growth rate of a wide range of Gram-negative and Gram-positive bacteria. The
addition of EDTA into DMEM lowered the growth rate, whereas the addition of BGE restored the growth activity. This study suggests
that sera contain a previously undescribed small BGE molecule. 相似文献
77.
Asada S Kuroda M Aoyagi Y Fukaya Y Tanaka S Konno S Tanio M Aso M Satoh K Okamoto Y Nakayama T Saito Y Bujo H 《American journal of physiology. Cell physiology》2011,301(1):C181-C185
Adipose tissue is expected to provide a source of proliferative cells for regenerative medicine and cell-transplantation therapies using gene transfer manipulation. We have recently identified ceiling culture-derived proliferative adipocytes (ccdPAs) from the mature adipocyte fraction as cells suitable as a therapeutic gene vehicle because of their stable proliferative capacity. In this study, we examined the capability of adipogenic differentiation of the ccdPAs compared with stromal vascular fraction (SVF)-derived progenitor cells (adipose-derived stem cells, ASCs) with regard to their multipotential ability to be converted to another lineage and therefore their potential to be used for regenerative medicine research. After in vitro passaging, the surface antigen profile and the basal levels of adipogenic marker genes of the ccdPAs were not obviously different from those of the ASCs. However, the ccdPAs showed increased lipid-droplet accumulation accompanied with higher adipogenic marker gene expression after stimulation of differentiation compared with the ASCs. The higher adipogenic potential of the ccdPAs than the ASCs from the SVF was maintained for 42 days in culture. Furthermore, the difference in the adipogenic response was enhanced after partial stimulation without indomethacin. These results indicate that the ccdPAs retain a high adipogenic potential even after in vitro passaging, thus suggesting the commitment of ccdPAs to stable mature adipocytes after autotransplantation, indicating that they may have potential for use in regenerative and gene-manipulated medicine. 相似文献
78.
Matsunaga H Hokari R Ueda T Kurihara C Hozumi H Higashiyama M Okada Y Watanabe C Komoto S Nakamura M Kawaguchi A Nagao S Sekiyama A Miura S 《American journal of physiology. Gastrointestinal and liver physiology》2011,301(3):G555-G564
Psychological stress is an environmental factor considered to be a precipitating factor of inflammatory bowel disease. Interleukin (IL)-18 plays a role in stress-induced aggravation in some diseases. The aim of this study was to establish a model of murine colitis exacerbated by psychological stress and to clarify the role of IL-18 in this model. Male C57Bl/6 mice and IL-18(-/-) mice were used for this study. The mice received dextran sulfate sodium (DSS) for induction of colitis. Some mice were exposed to psychological stress using a communication box. Body weight, colonic length, and histological inflammation were measured for assessment of colitis. Tumor necrosis factor (TNF)-α and IL-18 expression in the colon and IL-18 expression in the adrenal gland were analyzed using real-time PCR. The effect of anti-IL-18 antibody was also investigated. Effects of TNF-α and IL-18 on cytokine expressions were studied using the colonic epithelial cell line LS174T. Induction of psychological stress in DSS-treated wild-type mice significantly exacerbated colitis with enhanced expression of proinflammatory cytokines and IL-18. However, induction of psychological stress in DSS-treated IL-18(-/-) mice did not aggravate colitis compared with that in the IL-18(-/-) group given only DSS treatment. Stress-induced aggravation of colitis was ameliorated significantly by anti-IL-18 antibody treatment. IL-18 did not enhance TNF-α-induced expression of intercellular adhesion molecule-1 or IL-8 in LS174T. We established a model of colitis exacerbated by psychological stress. Psychological stress enhanced IL-18 expression and plays a proinflammatory role in stress-induced aggravation of colitis. 相似文献
79.
80.
Reiji Kojima Tatsukuni Ohno Motoyasu Iikura Toshiro Niki Mitsuomi Hirashima Keichi Iwaya Hitoshi Tsuda Shigeaki Nonoyama Akio Matsuda Hirohisa Saito Kenji Matsumoto Susumu Nakae 《PloS one》2014,9(1)
Galectin-9 (Gal-9), a lectin having a β-galactoside-binding domain, can induce apoptosis of Th1 cells by binding to TIM-3. In addition, Gal-9 inhibits IgE/Ag-mediated degranulation of mast cell/basophilic cell lines by binding to IgE, thus blocking IgE/Ag complex formation. However, the role of Gal-9 in mast cell function in the absence of IgE is not fully understood. Here, we found that recombinant Gal-9 directly induced phosphorylation of Erk1/2 but not p38 MAPK in a human mast cell line, HMC-1, which does not express FcεRI. Gal-9 induced apoptosis and inhibited PMA/ionomycin-mediated degranulation of HMC-1 cells. On the other hand, Gal-9 induced cytokine and/or chemokine production by HMC-1 cells, dependent on activation of ERK1/2 but not p38 MAPK. In addition, the lectin activity of Gal-9 was required for Gal-9-mediated cytokine secretion by HMC-1 cells. These observations suggest that Gal-9 has dual properties as both a regulator and an activator of mast cells. 相似文献