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331.
Lanying Zhao Hirotomo Saitsu Xiangnan Sun Kohei Shiota Makoto Ishibashi 《Mechanisms of development》2010,127(1-2):62-72
Accumulating evidence suggests that Sonic hedgehog (Shh) signaling plays a crucial role in eye vesicle patterning in vertebrates. Shh promotes expression of Pax2 in the optic stalk and represses expression of Pax6 in the optic cup. Shh signaling contributes to establishment of both proximal–distal and dorsal–ventral axes by activating Vax1, Vax2, and Pax2. In the dorsal part of the developing retina, Bmp4 is expressed and antagonizes the ventralizing effects of Shh signaling through the activation of Tbx5 expression in chick and Xenopus. To examine the roles of Shh signaling in optic cup formation and optic stalk development, we utilized the Smoothened (Smo) conditional knockout (CKO) mouse line. Smo is a membrane protein which mediates Shh signaling into inside of cells. Cre expression was driven by Fgf15 enhancer. The ventral evagination of the optic cup deteriorated from E10 in the Smo-CKO, whereas the dorsal optic cup and optic stalk develop normally until E11. We analyzed expression of various genes such as Pax family (Pax2/Pax6), Vax family (Vax1/Vax2) and Bmp4. Bmp4 expression was greatly upregulated in the optic vesicle by the 21-somite stage. Then Vax1/2 expression was decreased at the 20- to 24-somite stages. Pax2/6 expression was affected at the 27- to 32-somite stages. Our data suggest that the effects of the absence of Shh signaling on Vax1/Vax2 are mediated through increased Bmp4 expression throughout the optic cup. Also unchanged patterns of Raldh2 and Raldh3 suggest that retinoic acid is not the downstream to Shh signaling to control the ventral optic cup morphology. 相似文献
332.
Jun Ueyama Michihiro Kamijima Takaaki Kondo Kenji Takagi Eiji Shibata Takaaki Hasegawa Shinya Wakusawa Tomoko Taki Masahiro Gotoh Isao Saito 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(17-18):1257-1263
Among urinary organophosphorus pesticide (OP) metabolites, dialkyl phosphates (DAPs) have been most often measured as a sensitive biomarker in non-occupational and occupational OP exposure risk assessment. In our conventional method, we have employed a procedure including simple liquid–liquid extraction (diethyl ether/acetonitrile), derivatization (pentafluorobenzylbromide, PFBBr) and clean-up (multi-layer column) for gas chromatography–mass spectrometry (GC–MS) analysis starting from 5-mL urine samples. In this study, we introduce a revised analytical method for urinary DAPs; its main modification was aimed at improving the pre-derivatization dehydration procedure. The limits of detection were approximately 0.15 μg/L for dimethylphosphate (DMP), 0.07 μg/L for diethylphosphate (DEP), and 0.05 μg/L for both dimethylthiophosphate (DMTP) and diethylthiophosphate (DETP) in 2.5-mL human urine samples. Within-run precision (percent of relative standard deviation, %RSD) at the DAP levels varying in the range of 0.5–50 μg/L was 6.0–19.1% for DMP, 3.6–18.3% for DEP, 8.0–25.6% for DMTP and 9.6–27.8% for DETP. Between-run precision at 5 μg/L was below 15.7% for all DAPs. The revised method proved to be feasible to routine biological monitoring not only for occupational OP exposure but also for environmental background levels in the general population. Compared to our previous method, the revised method underscores the importance of adding pre-derivatization anhydration for higher sensitivity and precision. 相似文献
333.
Satoko Ito Hitoki Hasegawa Michinari Hamaguchi 《Biochemical and biophysical research communications》2010,400(2):230-235
Gap junctional communication, which is mediated by the connexin protein family, is essential for the maintenance of normal tissue function and homeostasis. Loss of intercellular communication results in a failure to coordinately regulate cellular functions, and it can facilitate tumorigenesis. Expression of oncogenes and stimulation with cytokines has been shown to suppress intercellular communication; however, the exact mechanism by which intercellular communication is disrupted by these factors remains uncertain. In this report, we show that Akt is essential for the disruption of gap junctional communication in v-Src-transformed cells. In addition, inhibition of Akt restores gap junctional communication after it is suppressed by TNF-α signaling. Furthermore, we demonstrate that the expression of a constitutively active form of Akt1, but not of Akt2 or Akt3, is sufficient to suppress gap junctional communication. Our results clearly define Akt1 as one of the critical regulators of gap junctional communication. 相似文献
334.
Fengming Yue Kohei Johkura Tadayuki Yokoyama Daihachiro Tomotsune 《Biochemical and biophysical research communications》2010,394(4):877-883
Purpose: Photoreceptors cannot regenerate and recover their functions once disordered. Transplantation of retinal pigment epithelium (RPE) has recently become a possible therapeutic approach for retinal degeneration. In the present study, we investigated the induction of photoreceptors by coculturing primate embryonic stem cells (ESCs) with ESC-derived RPE cells. Methods: RPE cells were derived by coculturing ESCs and Sertoli cells. Photoreceptors were then induced by using ESC-derived RPE cells and retinoic acid (RA) Results: RPE cell generation was confirmed by morphological analysis, which revealed highly pigmented polygonal cells with a compact cell-cell arrangement. After coculturing ESCs and RPE cells, some ESC derivatives became immunopositive for rhodopsin. RT-PCR analysis demonstrated the expression of retina-related gene markers such as Pax6, CRX, IRBP, rhodopsin, rhodopsin kinase, and Muschx10A. When RA was added, a distinct increase in the expression of photoreceptor-specific proteins and genes was found. In addition, the differentiation of bipolar horizontal cells was demonstrated by protein and gene expression. The ESCs that were cocultured with RPE cells and treated with RA were transplanted into the renal capsule or intra-vitreal space of nude mice. Grafted ESC derivatives demonstrated extensive rhodopsin expression, and they survived and organized into recipient tissues, although they formed teratomas. Conclusion: These results indicate that coculturing ESCs with ESC-derived RPE cells is a useful and efficient method for inducing photoreceptors and providing an insight into the use of ESCs for retina regeneration. 相似文献
335.
Koichi Murata Hiroyuki Yoshitomi Shimei Tanida Masahiro Ishikawa Kohei Nishitani Hiromu Ito Takashi Nakamura 《Arthritis research & therapy》2010,12(3):R86
Introduction
MicroRNAs (miRNAs), endogenous small noncoding RNAs regulating the activities of target mRNAs and cellular processes, are present in human plasma in a stable form. In this study, we investigated whether miRNAs are also stably present in synovial fluids and whether plasma and synovial fluid miRNAs could be biomarkers of rheumatoid arthritis (RA) and osteoarthritis (OA). 相似文献336.
Absence of leukotriene B4 receptor 1 confers resistance to airway hyperresponsiveness and Th2-type immune responses 总被引:1,自引:0,他引:1
Terawaki K Yokomizo T Nagase T Toda A Taniguchi M Hashizume K Yagi T Shimizu T 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(7):4217-4225
Bronchial asthma is an increasingly common disorder that remains poorly understood and difficult to manage. The disease is characterized by airway hyperresponsiveness, chronic inflammation, and mucus overproduction. Based on the finding that leukotriene B4 receptor 1 (BLT1) is expressed highly in Th2 lymphocytes, we analyzed the roles of BLT1 using an OVA-induced bronchial asthma model. BLT1-null mice did not develop airway hyperresponsiveness, eosinophilic inflammation, and hyperplasia of goblet cells. Attenuated symptoms were accompanied by reduced IgE production, and accumulation of IL-5 and IL-13 in bronchoalveolar lavage fluid, suggesting attenuated Th2-type immune response in BLT1-null mice. Peribronchial lymph node cells of sensitized BLT1-null mice showed much attenuated proliferation and production of Th2 cytokines upon re-stimulation with Ag in vitro. Thus, LTB4-BLT1 axis is required for the development of Th2-type immune response, and blockade of LTB4 functions through BLT1 would be novel and useful in the effort to ameliorate bronchial asthma and related Th2-biased immune disorders. 相似文献
337.
N,N-Dimethylformamidase (DMFase) from Alcaligenes sp. strain KUFA-1, a bacterium that can grow on N,N-dimethylformamide (DMF) as the sole carbon and nitrogen source, catalyzes the first step of the DMF degradation. The DMFase gene dmfA1A2 was cloned in Escherichia coli, and its nucleotides were sequenced. The deduced amino acid sequence of the enzyme consisted of two alpha- and two beta-subunits with 132 and 762 amino acids, respectively, and had little similarity to sequences in protein databases, including various amidases. The protein may be a new kind of amidase. DMFase activity was detected in E. coli cells transformed with an expression plasmid of the cloned DMFase gene. The properties of recombinant DMFase purified from E. coli were identical to those of Alcaligenes DMFase. 相似文献
338.
339.
Investigation of physicochemical form of uranium in sediment of brackish Lake Obuchi using sequential extraction procedure 总被引:1,自引:0,他引:1
The physicochemical form of uranium (238U) in the sediment of brackish Lake Obuchi was investigated using the standard procedures of sequential extraction. Approximately
60% to 70% of 238U was composed of the form bound to carbonates and iron (Fe)-manganese (Mn) oxides in silty sediments, whereas more than 50%
of 238U existed in the minerals of sandy sediments. The proportions of 238U bound to carbonates in the sediments of brackish Lake Obuchi were larger than those in fresh-water lake sediments. Most
of the uranium in the brackish lake sediment was considered to be mainly influenced by UO2(CO3)3
4− in seawater, judging from the fact that the 234U/ 238U activity ratios (1.13 to 1.16) of silty sediments were very close to that of seawater (1.14). The high correlation found
between the 238U concentration in the sediment and the amount of organic matter demonstrated that organic matter acts as a scavenger for
238U accumulation on the lake bottom.
Received: July 2, 1999 / Accepted: May 25, 2000 相似文献
340.
Kohei Hasegawa Yusuke Tsugawa Chu-Lin Tsai David FM Brown Carlos A Camargo Jr 《Respiratory research》2014,15(1):40