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841.
Akio Uemura Tetsuo Takehara Takuya Miyagi Takahiro Suzuki Tomohide Tatsumi Kazuyoshi Ohkawa Tatsuya Kanto Naoki Hiramatsu Norio Hayashi 《Cancer immunology, immunotherapy : CII》2010,59(3):453-463
Although the anti-tumor effect of IL-12 is mediated mostly by IFNγ, which cell types most efficiently produce IFNγ and therefore
initiate or promote the anti-tumor effect of IL-12 has not been clearly determined. In the present study, we demonstrated
hydrodynamic injection of the IL-12 gene led to prolonged IFNγ production, NK-cell activation and complete inhibition of liver
metastasis of CT-26 colon cancer cells in wild-type mice, but not in IFNγ knockout mice. NK cells expressed higher levels
of STAT4 and upon IL-12 administration displayed stronger STAT4 phosphorylation and IFNγ production than non-NK cells. Adoptive
transfer of wild-type NK cells into IFNγ knockout mice restored IL-12-induced IFNγ production, NK-cell activation and anti-tumor
effect, whereas transfer of the same number of wild-type non-NK cells did not. In conclusion, NK cells are predominant producers
of IFNγ that is critical for IL-12 anti-tumor therapy. 相似文献
842.
Takuya Ogawa 《Biochemical and biophysical research communications》2010,393(1):16-337
The gene of (all-E) geranylfarnesyl diphosphate synthase that is responsible for the biosynthesis of methanophenazine, an electron carrier utilized for methanogenesis, was cloned from a methanogenic archaeon Methanosarcina mazei Gö1. The properties of the recombinant enzyme and the results of phylogenetic analysis suggest that the enzyme is closely related to (all-E) prenyl diphosphate synthases that are responsible for the biosynthesis of respiratory quinones, rather than to the enzymes involved in the biosynthesis of archaeal membrane lipids, including (all-E) geranylfarnesyl diphosphate synthase from a thermophilic archaeon. 相似文献
843.
Kinuyo Yamashita Yoshitaka Nakajima Hayato Matsushita Ryuji Yamazawa Futoshi Matsubara Kiyoshi Ito Tadashi Yoshimoto 《Journal of molecular biology》2010,396(4):1081-1096
Creatininase is a binuclear zinc enzyme and catalyzes the reversible conversion of creatinine to creatine. It exhibits an open-closed conformational change upon substrate binding, and the differences in the conformations of Tyr121, Trp154, and the loop region containing Trp174 were evident in the enzyme-creatine complex when compared to those in the ligand-free enzyme. We have determined the crystal structure of the enzyme complexed with a 1-methylguanidine. All subunits in the complex existed as the closed form, and the binding mode of creatinine was estimated. Site-directed mutagenesis revealed that the hydrophobic residues that show conformational change upon substrate binding are important for the enzyme activity.We propose a catalytic mechanism of creatininase in which two water molecules have significant roles. The first molecule is a hydroxide ion (Wat1) that is bound as a bridge between the two metal ions and attacks the carbonyl carbon of the substrate. The second molecule is a water molecule (Wat2) that is bound to the carboxyl group of Glu122 and functions as a proton donor in catalysis. The activity of the E122Q mutant was very low and it was only partially restored by the addition of ZnCl2 or MnCl2. In the E122Q mutant, kcat is drastically decreased, indicating that Glu122 is important for catalysis. X-ray crystallographic study and the atomic absorption spectrometry analysis of the E122Q mutant-substrate complex revealed that the drastic decrease of the activity of the E122Q was caused by not only the loss of one Zn ion at the Metal1 site but also a critical function of Glu122, which most likely exists for a proton transfer step through Wat2. 相似文献
844.
Takuya Koseki Keiji Mochizuki Hiroe Kisara Akimasa Miyanaga Shinya Fushinobu Tetsuya Murayama Yoshihito Shiono 《Applied microbiology and biotechnology》2010,86(1):155-161
We engineered a chimeric enzyme (AwFaeA-CBM42) comprising of type-A feruloyl esterase from Aspergillus awamori (AwFaeA) and family 42 carbohydrate-binding module (AkCBM42) from glycoside hydrolase family 54 α-l-arabinofuranosidase of Aspergillus kawachii. The chimeric enzyme was successfully produced in Pichia pastoris and accumulated in the culture broth. The purified chimeric enzyme had an apparent relative molecular mass (M
r) of 53,000. The chimeric enzyme binds to arabinoxylan; this indicates that the AkCBM42 in AwFaeA-CBM42 binds to arabinofuranose
side chain moiety of arabinoxylan. The thermostability of the chimeric enzyme was greater than that of AwFaeA. No significant
difference of the specific activity toward methyl ferulate was observed between the AwFaeA and chimeric enzyme, but the release
of ferulic acid from insoluble arabinoxylan by the chimeric enzyme was approximately 4-fold higher than that achieved by AwFaeA
alone. In addition, the chimeric enzyme and xylanase acted synergistically for the degradation of arabinoxylan. In conclusion,
the findings of our study demonstrated that the components of the AwFaeA-CBM42 chimeric enzyme act synergistically to bring
about the degradation of complex substrates and that the family 42 carbohydrate-binding module has potential for application
in the degradation of polysaccharides. 相似文献
845.
Noriko Sumi Tsuyoshi Nishioku Fuyuko Takata Junichi Matsumoto Takuya Watanabe Hideki Shuto Atsushi Yamauchi Shinya Dohgu Yasufumi Kataoka 《Cellular and molecular neurobiology》2010,30(2):247-253
The blood–brain barrier (BBB) is formed by brain capillary endothelial cells, astrocytes, pericytes, microglia, and neurons.
BBB disruption under pathological conditions such as neurodegenerative disease and inflammation is observed in parallel with
microglial activation. To test whether activation of microglia is linked to BBB dysfunction, we evaluated the effect of lipopolysaccharide
(LPS) on BBB functions in an in vitro co-culture system with rat brain microvascular endothelial cells (RBEC) and microglia.
When LPS was added for 6 h to the abluminal side of RBEC/microglia co-culture at a concentration showing no effects on the
RBEC monolayer, transendothelial electrical resistance was decreased and permeability to sodium-fluorescein was increased
in RBEC. Immunofluorescence staining for tight junction proteins demonstrated that zonula occludens-1-, claudin-5-, and occludin-like
immunoreactivities at the intercellular borders of RBEC were fragmented in the presence of LPS-activated microglia. These
functional changes induced by LPS-activated microglia were blocked by the nicotinamide adenine dinucleotide phosphate (NADPH)
oxidase inhibitor, diphenyleneiodonium chloride. The present findings suggest that LPS activates microglia to induce dysfunction
of the BBB by producing reactive oxygen species through NADPH oxidase. 相似文献
846.
847.
Taiyo Toriba Takuya Suzaki Takahiro Yamaguchi Yoshihiro Ohmori Hirokazu Tsukaya Hiro-Yuki Hirano 《The Plant cell》2010,22(5):1452-1462
Establishment of adaxial-abaxial polarity is essential for lateral organ development. The mechanisms underlying the polarity establishment in the stamen remain unclear, whereas those in the leaf are well understood. Here, we investigated a rod-like lemma (rol) mutant of rice (Oryza sativa), in which the development of the stamen and lemma is severely compromised. We found that the rod-like structure of the lemma and disturbed anther patterning resulted from defects in the regulation of adaxial-abaxial polarity. Gene isolation indicated that the rol phenotype was caused by a weak mutation in SHOOTLESS2 (SHL2), which encodes an RNA-dependent RNA polymerase and functions in trans-acting small interfering RNA (ta-siRNA) production. Thus, ta-siRNA likely plays an important role in regulating the adaxial-abaxial polarity of floral organs in rice. Furthermore, we found that the spatial expression patterns of marker genes for adaxial-abaxial polarity are rearranged during anther development in the wild type. After this rearrangement, a newly formed polarity is likely to be established in a new developmental unit, the theca primordium. This idea is supported by observations of abnormal stamen development in the shl2-rol mutant. By contrast, the stamen filament is likely formed by abaxialization. Thus, a unique regulatory mechanism may be involved in regulating adaxial-abaxial polarity in stamen development. 相似文献
848.
Saori Kunii Koichi Morimoto Kouhei Nagai Takuya Saito Kenji Sato Ben'ichiro Tonomura 《The Journal of biological chemistry》2010,285(23):17465-17470
We investigated the ability of type I collagen telopeptides to bind neighboring collagen molecules, which is thought to be the initial event in fibrillogenesis. Limited hydrolysis by actinidain protease produced monomeric collagen, which consisted almost entirely of α1 and α2 chains. As seen with ultrahigh resolution scanning electron microscopy, actinidain-hydrolyzed collagen exhibited unique self-assembly, as if at an intermediate stage, and formed a novel suprastructure characterized by poor fibrillogenesis. Then, the N- and C-terminal sequences of chicken type I collagen hydrolyzed by actinidain or pepsin were determined by Edman degradation and de novo sequence analysis with matrix-assisted laser desorption ionization-tandem time-of-flight mass spectrometry, respectively. In the C-telopeptide region of the α1 chain, pepsin cleaved between Asp1035 and Phe1036, and actinidain between Gly1032 and Gly1033. Thus, the actinidain-hydrolyzed α1 chain is shorter at the C terminus by three residues, Gly1033, Phe1034, and Asp1035. In the α2 chain, both proteases cleaved between Glu1030 and Val1031. We demonstrated that a synthetic nonapeptide mimicking the α1 C-terminal sequence including GFD weakly inhibited the self-assembly of pepsin-hydrolyzed collagen, whereas it remarkably accelerated that of actinidain-hydrolyzed collagen. We conclude that the specific GFD sequence of the C-telopeptide of the α1 chain plays a crucial role in stipulating collagen suprastructure and in subsequent fibril formation. 相似文献
849.
850.
Taiji Hatakeyama Takuya Koseki Tetsuya Murayama Yoshihito Shiono 《Phytochemistry letters》2010,3(3):148-151
Two new eremophilane sesquiterpenes, compounds 1 and 2, were isolated from the endophytic fungus Microdiplodia sp. KS 75-1, together with the known compounds phomadecalins C (3) and D (4). Their structures were determined by extensive 1D– and 2D–NMR and MS spectral analyses. The previously reported stereochemistry at C-8 of 3 and 4 were revised on the basis of NOEs experiments. Compounds 1 and 2 showed antimicrobial activity against Pseudomonas aeruginosa. 相似文献