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排序方式: 共有125条查询结果,搜索用时 15 毫秒
101.
Jerry W. Hupp Noriyuki Yamaguchi Paul L. Flint John M. Pearce Ken‐ichi Tokita Tetsuo Shimada Andrew M. Ramey Sergei Kharitonov Hiroyoshi Higuchi 《Journal of avian biology》2011,42(4):289-300
In North America, spring migration routes and breeding distribution of northern pintails Anas acuta vary because some individuals opportunistically nest at mid‐latitudes in years when ephemeral prairie wetlands are available, whereas others regularly nest in arctic and sub‐arctic regions where wetland abundance is more constant. Less was known about migration routes and breeding distribution of pintails in East Asia. From 2007–2009 we marked 198 pintails on their wintering areas in Japan with satellite transmitters to: 1) document spring migration routes and summer distribution, 2) evaluate migratory connections and breeding season sympatry with North American pintails, and 3) determine if pintails used the same migration routes in fall as in spring. Most pintails (67%) migrated to the Kamchatka or Chukotka peninsulas in eastern Russia either directly from Japan or via Sakhalin Island, Russia. Remaining pintails primarily migrated to the Magadan region or Kolyma River Basin in eastern Russia via Sakhalin Island. The Chukotka Peninsula was the most common summer destination, with highest densities in the Anadyr Lowlands; a region also used by pintails that migrate from North America. One pintail migrated to St. Lawrence Island, Alaska, in spring and another briefly migrated to the western coast of Alaska in fall. Autumn migration routes generally mirrored spring migration although most pintails bypassed Sakhalin Island in fall. Compared to North American pintails, pintails that winter in Japan exhibited less variation in migration routes and breeding distribution, and nested at higher latitudes. In the Russian Far East there is no region with habitats comparable in extent to the ephemeral mid‐latitude wetlands of North America. Consequently, East Asian pintails mainly nest in arctic and sub‐arctic regions where annual consistency in wetlands promotes constancy in migration routes and breeding distribution. Breeding season sympatry between pintails from different continents results more from North American pintails migrating to eastern Russia than from Japanese pintails migrating to North America. 相似文献
102.
Tadashi Tatematsu Masashi Kimura Mitsuko Nakashima Junichiro Machida Seishi Yamaguchi Akio Shibata Hiroki Goto Atsuo Nakayama Yujiro Higashi Hitoshi Miyachi Kazuo Shimozato Naomichi Matsumoto Yoshihito Tokita 《PloS one》2015,10(6)
Congenital tooth agenesis is caused by mutations in the MSX1, PAX9, WNT10A, or AXIN2 genes. Here, we report a Japanese family with nonsyndromic tooth agenesis caused by a novel nucleotide substitution in the intronic region between exons 1 and 2 of the MSX1 gene. Because the mutation is located 9 bp before exon 2 (c.452-9G>A), we speculated that the nucleotide substitution would generate an abnormal splice site. Using cDNA analysis of an immortalized patient blood cell, we confirmed that an additional 7-nucleotide sequence was inserted at the splice junction between exons 1 and 2 (c.451_452insCCCTCAG). The consequent frameshift generated a homeodomain-truncated MSX1 (p.R151fsX20). We then studied the subcellular localization of truncated MSX1 protein in COS cells, and observed that it had a whole cell distribution more than a nuclear localization, compared to that of wild-type protein. This result suggests a deletion of the nuclear localization signal, which is mapped to the MSX1 homeodomain. These results indicate that this novel intronic nucleotide substitution is the cause of tooth agenesis in this family. To date, most MSX1 variants isolated from patients with tooth agenesis involve single amino acid substitutions in the highly conserved homeodomain or deletion mutants caused by frameshift or nonsense mutations. We here report a rare case of an intronic mutation of the MSX1 gene responsible for human tooth agenesis. In addition, the missing tooth patterns were slightly but significantly different between an affected monozygotic twin pair of this family, showing that epigenetic or environmental factors also affect the phenotypic variations of missing teeth among patients with nonsyndromic tooth agenesis caused by an MSX1 haploinsufficiency. 相似文献
103.
Tsujimura S Fukuda J Shirai O Kano K Sakai H Tokita Y Hatazawa T 《Biosensors & bioelectronics》2012,34(1):244-248
The mediated electro-enzymatic electrolysis systems based on the tricarboxylic acid (TCA) cycle reaction were examined on a micro-bulk electrolytic system. A series of the enzyme-catalyzed reactions in the TCA cycle was coupled with electrode reaction. Electrochemical oxidation of NADH was catalyzed by diaphorase with an aid of a redox mediator with a formal potential of -0.15 V vs. Ag|AgCl. The mediator was also able to shuttle electrons between succinate dehydrogenase and electrode. The charge during the electrolysis increased on each addition of dehydrogenase reaction in a cascade of the TCA cycle. However, the electrolysis efficiencies were close to or less than 90% because of the product inhibition. Lactate oxidation to acetyl-CoA catalyzed by two NAD-dependent dehydrogenases was coupled with the bioelectrochemical TCA cycle reaction to achieve the 12-electron oxidation of lactate to CO(2). The charge passed in the bioelectrocatalytic oxidation of 5 nmol of lactate was 4 mC, which corresponds to 70% of the electrolysis efficiency. 相似文献
104.
Masahiko Ito Toshihiro Sakamoto Takao Suzuki Shinichiro Egashira Minoru Moriya Akane Ishihara Hisashi Iwaasa Hiroko Matsushita Kazuho Nakase Michael A. Wallace Dennis Dean Nagaaki Sato Shigeru Tokita Akio Kanatani 《Bioorganic & medicinal chemistry letters》2009,19(10):2835-2839
We have developed and characterized [35S]4a as a potent and selective radioligand for melanin-concentrating hormone 1-receptor (MCH1R). Compound [35S]4a showed appreciable specific signals in brain slices prepared from wild-type mice but not from MCH1R deficient mice, confirming the specificity and utility of [35S]4a as a selective MCH1R radioligand for ex vivo receptor occupancy assays. 相似文献
105.
Yuko Mitobe Sayaka Ito Takashi Mizutani Tsuyoshi Nagase Nagaaki Sato Shigeru Tokita 《Bioorganic & medicinal chemistry letters》2009,19(15):4075-4078
Radioligands are powerful tools for examining the pharmacological profiles of chemical leads and thus facilitate drug discovery. In this study, we identified and characterized 3-([1,1,1-3H]methyl)-2-(4-{[3-(1-pyrrolidinyl)propyl]oxy} phenyl)-4(3H)-quinazolinone ([3H]1) as a potent and selective radioligand for histamine H3 receptors. Radioligand [3H]1 exhibited appreciable specific signal in brain slices prepared from wild-type mice but not from histamine H3 receptor-deficient mice, demonstrating the specificity and utility of [3H]1 as a selective histamine H3 receptor radioligand for ex-vivo receptor occupancy assays. 相似文献
106.
Takahide Sasaki Toshiyuki Takahashi Tsuyoshi Nagase Takashi Mizutani Sayaka Ito Yuko Mitobe Yasuhisa Miyamoto Maki Kanesaka Ryo Yoshimoto Takeshi Tanaka Norihiro Takenaga Shigeru Tokita Nagaaki Sato 《Bioorganic & medicinal chemistry letters》2009,19(15):4232-4236
A series of novel dihydrobenzoxathiin derivatives was synthesized and evaluated as potent human histamine H3 receptor inverse agonists. After systematic modification of lead 1a, the potent and selective histamine H3 inverse agonist 1-(3-{4-[(2S,3S)-8-methoxy-3-methyl-4,4-dioxido-2,3-dihydro-1,4-benzoxathiin-2-yl]phenoxy}propyl)pyrrolidine (5k) was identified. Compound 5k showed good pharmacokinetic profiles and brain penetrability in laboratory animals. After 3 mg/kg oral administration of 5k, significant elevation of brain histamine levels was observed in rats where the brain H3 receptor was fully occupied. 相似文献
107.
I Ono I Ishiwata T Nakaguchi K Konoe N Tokita M Soma C Ishiwata H Ishikawa 《Human cell》1989,2(1):74-79
The heterotransplantability of HOTHC line (human anaplastic thyroid carcinoma) into the subcutis of BALB/c nude mice and the biological properties of grafts were discussed. (1) The HOTHC line showed high transplantability, and 1 x 10(4) cells produced anaplastic carcinoma (giant cell type) containing the colloid-like substance. (2) The grafted tumors grew rapidly and the mice were dead within 2 months after transplantation. (3) The number of leukocytes (neutrophils) of mouse peripheral blood increased as the tumor size increased, and the leukocyte count returned to a normal value after removal of the tumor. (4) The conditioned media of HOTHC line formed colonies of granulocytes (neutrophils) on soft agar. These phenomena revealed that HOTHC is a granulocyte-colony stimulating factor-producing line. (5) The conditioned media of HOTHC line showed promoting-effect on neovascularization on the chorioallantoic membrane. 相似文献
108.
Carmona FD Motokawa M Tokita M Tsuchiya K Jiménez R Sánchez-Villagra MR 《Journal of experimental zoology. Part B. Molecular and developmental evolution》2008,310(3):259-266
Previous studies of the reproductive biology and genetics of European moles (Talpa spp.) showed that all females of these species have ovotestes (gonads with testicular and ovarian tissue) instead of normal ovaries, a unique specialization among mammals. Females are fertile as their ovarian tissue is fully functional. Testicular tissue is abnormal and sterile, but produces high levels of testosterone. This phenomenon also characterizes other talpid species from Europe and North America. To study the origin of this singular reproductive specialization, we examined the gonads of several female specimens belonging to two critical taxa. Although large Japanese moles (Mogera wogura) posses ovotestes, greater Japanese shrew moles (Urotrichus talpoides) are characterized by normal ovaries. The results fit parsimoniously with a recent phylogenetic study that places Urotrichus relatively basal in the talpid tree and separate from the American shrew mole. Parsimony reconstruction on alternative phylogenetic hypotheses clearly indicates that reversal(s) must have occurred and suggests that a relatively simple genetic mechanism must be associated with the evolution of female hermaphroditism in moles. 相似文献
109.
Onoe T Ohdan H Tokita D Shishida M Tanaka Y Hara H Zhou W Ishiyama K Mitsuta H Ide K Asahara T 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(1):139-146
Although livers transplanted across MHC barriers in mice are normally accepted without recipient immune suppression, the underlying mechanisms remain to be clarified. To identify the cell type that contributes to induction of such a tolerance state, we established a mixed hepatic constituent cell-lymphocyte reaction (MHLR) assay. Irradiated C57BL/6 (B6) or BALB/c mouse hepatic constituent cells (HCs) and CFSE-labeled B6 splenocytes were cocultured. In allogeneic MHLR, whole HCs did not promote T cell proliferation. When liver sinusoidal endothelial cells (LSECs) were depleted from HC stimulators, allogeneic MHLR resulted in marked proliferation of reactive CD4(+) and CD8(+) T cells. To test the tolerizing capacity of the LSECs toward alloreactive T cells, B6 splenocytes that had transmigrated through monolayers of B6, BALB/c, or SJL/j LSECs were restimulated with irradiated BALB/c splenocytes. Nonresponsiveness of T cells that had transmigrated through allogeneic BALB/c LSECs and marked proliferation of T cells transmigrated through syngeneic B6 or third-party SJL/j LSECs were observed after the restimulation. Transmigration across the Fas ligand-deficient BALB/c LSECs failed to render CD4(+) T cells tolerant. Thus, we demonstrate that Fas ligand expressed on naive LSECs can impart tolerogenic potential upon alloantigen recognition via the direct pathway. This presents a novel relevant mechanism of liver allograft tolerance. In conclusion, LSECs are capable of regulating a polyclonal population of T cells with direct allospecificity, and the Fas/Fas ligand pathway is involved in such LSEC-mediated T cell regulation. 相似文献
110.
Unno A Takada I Takezawa S Oishi H Baba A Shimizu T Tokita A Yanagisawa J Kato S 《Biochemical and biophysical research communications》2005,327(3):933-938
TBP-free TAF II-containing-type HAT complex subclasses, which contain hGCN5 HAT and TRRAP, appear to act as common coactivator complexes for nuclear receptors. However, their physiological significance with respect to each nuclear receptor remains to be established. To address this issue, we used hepatic cell lines (HepG2) with reduced endogenous TRRAP expression through antisense RNA expression or with overexpressed TRRAP or other major coactivators. The ligand-induced transactivation function of liver X receptor alpha (LXRalpha) and farnesoid X receptor/bile acid receptor reflected TRRAP expression levels, while that of PPARgamma did not. A GST pull-down assay indicated that TRRAP contains two potential LXRalpha-interacting domains in the C-terminal and central domains. Expression of antisense TRRAP RNA in HepG2 cells abolished the ligand-induced expression of LXRalpha target genes. These results suggested that TRRAP plays an important role as a coactivator, presumably part of a complex, in lipid metabolism through regulation of the LXRalpha-mediated gene cascade in hepatic cells. 相似文献