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121.
Yukari Matsushima Kazuki Terada Jiro Takata Yoshiharu Karube Chiaki Kamei 《Bioscience, biotechnology, and biochemistry》2019,83(4):659-665
In the present study, we examined the effects of fluvoxamine on nerve growth factor (NGF)-induced neurite outgrowth inhibition by dexamethasone (DEX) in PC12 cells. Fluvoxamine increased NGF-induced neurite outgrowth. Compared with co-treatment with NGF and fluvoxamine, p-Akt levels were higher than the values without fluvoxamine. The phosphorylated extracellular regulated kinase 1/2 levels were slightly increased by co-treatment with NGF and fluvoxamine. Fluvoxamine concentration-dependently improved NGF-induced neurite outgrowth inhibition by DEX. Fluvoxamine also improved the decrease in the NGF-induced p-Akt level caused by DEX. Interestingly, the sigma-1 receptor antagonist NE-100 blocked the improvement effects of fluvoxamine on NGF-induced neurite outgrowth inhibition by DEX. The selective sigma-1 receptor agonist PRE-084 also improved NGF-induced neurite outgrowth inhibition by DEX, which is blocked by NE-100. These results indicate that the improvement effects of fluvoxamine on NGF-induced neurite outgrowth inhibition by DEX may be attributable to the phosphorylation of Akt and the sigma-1 receptor. 相似文献
122.
123.
Kondo M Nakamura Y Fujii K Nagata M Suemori Y Dewa T Iida K Gardiner AT Cogdell RJ Nango M 《Biomacromolecules》2007,8(8):2457-2463
Light-harvesting antenna core (LH1-RC) complexes isolated from Rhodoseudomonas palustris were self-assembled on a gold electrode modified with self-assembled monolayers (SAMs) of the alkanethiols NH2(CH2)nSH, n = 2, 6, 8, 11; HOOC(CH2)7SH; and CH3(CH2)7SH, respectively. Adsorption of the LH1-RC complexes on the SAMs depended on the terminating group of the alkanethiols, where the adsoption increased in the following order for the terminating groups: amino groups > carboxylic acid groups > methyl groups. Further, the adsorption on a gold electrode modified with SAMs of NH2(CH2)nSH, n = 2, 6, 8, 11, depended on the methylene chain length, where the adsorption increased with increasing the methylene chain length. The presence of the well-known light-harvesting and reaction center peaks of the near infrared (NIR) absorption spectra of the LH1-RC complexes indicated that these complexes were only fully stable on the SAM gold electrodes modified with the amino group. In the case of modification with the carboxyl group, the complexes were partially stable, while in the presence of the terminal methyl group the complexes were extensively denatured. An efficient photocurrent response of these complexes on the SAMs of NH2(CH2)nSH, n = 2, 6, 8, 11, was observed upon illumination at 880 nm. The photocurrent depended on the methylene chain length (n), where the maximum photocurrent response was observed at n = 6, which corresponds to a distance between the amino terminal group in NH2(CH2)6SH and the gold surface of 1.0 nm. 相似文献
124.
125.
Ando H Shimizu H Katano Y Koike Y Koizumi S Ishida H Kiso M 《Carbohydrate research》2006,341(10):1522-1532
A synthetic study on alpha-(1-->4) and alpha-(1-->8)-fucosylation of sialic acid is reported, with the ultimate aim being the total assembly of the glycan portion of HPG-series gangliosides. In both types of fucosylations, the combination of a phenylthio fucosyl donor and a 1,5-lactamized acceptor provided high-yielding glycosylations to afford alpha-fucosyl-sialic acid sequences. The obtained alpha-Fucp-(1-->8)-NeupNAc glycan having a 1,5-lactam bridge has been successfully transformed into the corresponding glycosyl donor. 相似文献
126.
Uehara A Fujimoto Y Kawasaki A Kusumoto S Fukase K Takada H 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(3):1796-1804
Peptidoglycans (PGNs) are ubiquitous constituents of bacterial cell walls and exhibit various immunobiological activities. Two types of minimum essential PGN structures for immunobiological activities were chemically synthesized and designated as muramyldipeptide; N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) and gamma-D-glutamyl-meso-diaminopimelic acid (iE-DAP), which are common constituents of both Gram-positive and Gram-negative bacteria, as well as most Gram-negative and some Gram-positive bacteria, respectively. Recently, intracellular receptors for MDP and iE-DAP have been demonstrated to be nucleotide-binding oligomerization domain (NOD)1 and NOD2, respectively. In this study, we demonstrated that chemically synthesized meso-DAP itself activated human epithelial cells from various tissues, through NOD1 to generate antibacterial factors, PGN recognition proteins and beta-defensin 2, and cytokines in specified cases, although the activities of meso-DAP were generally weaker than those of known NOD agonists. However, stereoisomers of meso-DAP, LL-DAP, and DD-DAP were only slightly activated or remained inactive, respectively. Synthetic meso-lanthionine, which is another diamino-type amino acid specific to PGN of the specified Gram-negative bacteria, was also recognized by NOD1. In human monocytic cells, in the presence of cytochalasin D meso-DAP induced slightly but significantly increased production of cytokines, although the cells did not respond to meso-DAP in the absent of cytochalasin D. Our findings suggest that NOD1 is a special sentinel molecule, especially in the epithelial barrier, allowing the intracellular detection of bacteria through recognizing meso-DAP or comparable moiety of PGN from specified bacteria in cooperation with NOD2, thereby playing a key role in innate immunity. 相似文献
127.
Kobayashi M Saitoh S Tanimura N Takahashi K Kawasaki K Nishijima M Fujimoto Y Fukase K Akashi-Takamura S Miyake K 《Journal of immunology (Baltimore, Md. : 1950)》2006,176(10):6211-6218
LPS, a principal membrane component in Gram-negative bacteria, is recognized by a receptor complex consisting of TLR4 and MD-2. MD-2 is an extracellular molecule that is associated with the extracellular domain of TLR4 and has a critical role in LPS recognition. MD-2 directly interacts with LPS, and the region from Phe(119) to Lys(132) (Arg(132) in mice) has been shown to be important for interaction between LPS and TLR4/MD-2. With mouse MD-2 mutants, we show in this study that Gly(59) was found to be a novel critical amino acid for LPS binding outside the region 119-132. LPS signaling is thought to be triggered by ligand-induced TLR4 clustering, which is also regulated by MD-2. Little is known, however, about a region or an amino acid in the MD-2 molecule that regulates ligand-induced receptor clustering. MD-2 mutants substituting alanine for Phe(126) or Gly(129) impaired LPS-induced TLR4 clustering, but not LPS binding to TLR4/MD-2, demonstrating that ligand-induced receptor clustering is differentially regulated by MD-2 from ligand binding. We further show that dissociation of ligand-induced receptor clustering and of ligand-receptor interaction occurs in a manner dependent on TLR4 signaling and requires endosomal acidification. These results support a principal role for MD-2 in LPS recognition. 相似文献
128.
Hikosaka K Koyama Y Motobu M Yamada M Nakamura K Koge K Shimura K Isobe T Tsuji N Kang CB Hayashidani H Wang PC Matsumura M Hirota Y 《Bioscience, biotechnology, and biochemistry》2006,70(12):2853-2858
A sugar cane extract (SCE) has been found to have an immunostimulating effect in several animals. Lipopolysaccharide (LPS) is known to induce endotoxin shock via the production of inflammatory modulators such as tumor necrosis factor (TNF)-alpha and nitric oxide (NO). We examined in the present study the effects of SCE on the TNF-alpha and NO production in LPS-stimulated mice peritoneal cells and the endotoxin shock in mice. The supplementation of SCE to peritoneal macrophages cultured with LPS resulted in a significant decrease in NO production. All the mice injected intraperitoneally with LPS and D-galactosamine (LPS+GalN) died within 24 h. However, a peritoneal injection, but no intravenous or oral administration, of SCE (500-1,000 mg/kg) at 3 to 48 h before the LPS+GalN-challenge resulted in a significantly improved survival rate. These results suggest that SCE had a protective effect on LPS-induced endotoxin shock via one of possible mechanisms involving the suppression of NO production in the mouse peritoneal cavity. 相似文献
129.
Miyata K Miyashita M Nose R Otake Y Miyagawa H 《Bioscience, biotechnology, and biochemistry》2006,70(9):2138-2144
Plants exhibit various defense responses after recognizing elicitor molecules derived from pathogenic microorganisms and host plants. In this study, we developed an improved colorimetric assay for quantifying the generation of H2O2 in plant cells, one of the defense responses, to evaluate elicitor activity quantitatively. H2O2 is detected using a dye, N-(carboxymethylaminocarbonyl)-4,4'-bis(dimethylamino)-diphenylamine sodium salt (DA-64), which can be measured by conventional spectrometers in a highly sensitive and quantitative manner. Using this method, we successfully measured the elicitor activity of flagellin-derived peptides in cultured tobacco cells, and identified several structural features of the peptides important for the elicitor activity. The results suggest that the structural factors required for expression of the elicitor activity differ slightly among plant species. The efficient and sensitive assay developed in this study should be useful not only for studying structure-activity relationships, but also for the screening of novel compounds that can induce defense responses. 相似文献
130.
Atsushi Kawaguchi Yukari Suzuki Jeremy R H Tame Kyosuke Nagata Sam‐Yong Park 《The EMBO journal》2009,28(12):1803-1811
Influenza virus RNA‐dependent RNA polymerase is a multi‐functional heterotrimer, which uses a ‘cap‐snatching’ mechanism to produce viral mRNA. Host cell mRNA is cleaved to yield a cap‐bearing oligonucleotide, which can be extended using viral genomic RNA as a template. The cap‐binding and endonuclease activities are only activated once viral genomic RNA is bound. This requires signalling from the RNA‐binding PB1 subunit to the cap‐binding PB2 subunit, and the interface between these two subunits is essential for the polymerase activity. We have defined this interaction surface by protein crystallography and tested the effects of mutating contact residues on the function of the holo‐enzyme. This novel interface is surprisingly small, yet, it has a crucial function in regulating the 250 kDa polymerase complex and is completely conserved among avian and human influenza viruses. 相似文献