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111.
Masuko Suzuki Takeshi Mikami Tatsuji Matsumoto Shigeo Suzuki 《Microbiology and immunology》1977,21(8):419-425
The Limulus test has been considered specific for the presence of bacterial endotoxins. To synthesize a simple model of endotoxin, palmitoyldextran phosphate was prepared by modification of dextran by palmitoylation and phosphorylation. The present studies indicated that a variety of polysaccharide derivatives, such as palmitoyldextran phosphate, palmitoyldextran, and dextran phosphate, give a positive Limulus test and show pyrogenic activity, except for low molecular dextran derivatives. On the other hand, polysaccharides, such as dextran, starch (soluble), chitosan, xylan, and lentinan, were negative in these assays. The gelation reaction of Limulus lysate by modified dextran derivatives may depend on the molecular weight or modification of polysaccharides by palmitoylation and/or phosphorylation to a great extent. 相似文献
112.
113.
Matsumoto Narihisa Mototake Yoh-ichi Kawano Kenji Okada Masato Sugase-Miyamoto Yasuko 《Journal of computational neuroscience》2021,49(3):251-257
Journal of Computational Neuroscience - Feed-forward deep neural networks have better performance in object categorization tasks than other models of computer vision. To understand the relationship... 相似文献
114.
Ken'ichiro Matsumoto Yoshikazu Tanaka Tsuyoshi Watanabe Ren Motohashi Koji Ikeda Kota Tobitani Min Yao Isao Tanaka Seiichi Taguchi 《Applied and environmental microbiology》2013,79(19):6134-6139
NADPH-dependent acetoacetyl-coenzyme A (acetoacetyl-CoA) reductase (PhaB) is a key enzyme in the synthesis of poly(3-hydroxybutyrate) [P(3HB)], along with β-ketothiolase (PhaA) and polyhydroxyalkanoate synthase (PhaC). In this study, PhaB from Ralstonia eutropha was engineered by means of directed evolution consisting of an error-prone PCR-mediated mutagenesis and a P(3HB) accumulation-based in vivo screening system using Escherichia coli. From approximately 20,000 mutants, we obtained two mutant candidates bearing Gln47Leu (Q47L) and Thr173Ser (T173S) substitutions. The mutants exhibited kcat values that were 2.4-fold and 3.5-fold higher than that of the wild-type enzyme, respectively. In fact, the PhaB mutants did exhibit enhanced activity and P(3HB) accumulation when expressed in recombinant Corynebacterium glutamicum. Comparative three-dimensional structural analysis of wild-type PhaB and highly active PhaB mutants revealed that the beneficial mutations affected the flexibility around the active site, which in turn played an important role in substrate recognition. Furthermore, both the kinetic analysis and crystal structure data supported the conclusion that PhaB forms a ternary complex with NADPH and acetoacetyl-CoA. These results suggest that the mutations affected the interaction with substrates, resulting in the acquirement of enhanced activity. 相似文献
115.
Kazuto Ishikawa Takashi Ohmori Hirokuni Miyamoto Toshiyuki Ito Yoshifumi Kumagai Masatoshi Sonoda Jirou Matsumoto Hisashi Miyamoto Hiroaki Kodama 《Applied microbiology and biotechnology》2013,97(3):1349-1359
NO 3 ? is a major nitrogen source for plant nutrition, and plant cells store NO 3 ? in their vacuoles. Here, we report that a unique compost made from marine animal resources by thermophiles represses NO 3 ? accumulation in plants. A decrease in the leaf NO 3 ? content occurred in parallel with a decrease in the soil NO 3 ? level, and the degree of the soil NO 3 ? decrease was proportional to the compost concentration in the soil. The compost-induced reduction of the soil NO 3 ? level was blocked by incubation with chloramphenicol, indicating that the soil NO 3 ? was reduced by chloramphenicol-sensitive microbes. The compost-induced denitrification activity was assessed by the acetylene block method. To eliminate denitrification by the soil bacterial habitants, soil was sterilized with γ irradiation and then compost was amended. After the 24-h incubation, the N2O level in the compost soil with presence of acetylene was approximately fourfold higher than that in the compost soil with absence of acetylene. These results indicate that the low NO 3 ? levels that are often found in the leaves of organic vegetables can be explained by compost-mediated denitrification in the soil. 相似文献
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117.
Shigemitsu Matsumoto Naoki Miyamoto Takaharu Hirayama Hideyuki Oki Kengo Okada Michiko Tawada Hidehisa Iwata Kazuhide Nakamura Seiji Yamasaki Hiroshi Miki Akira Hori Shinichi Imamura 《Bioorganic & medicinal chemistry》2013,21(24):7686-7698
To identify compounds with potent antitumor efficacy for various human cancers, we aimed to synthesize compounds that could inhibit c-mesenchymal epithelial transition factor (c-Met) and vascular endothelial growth factor receptor 2 (VEGFR2) kinases. We designed para-substituted inhibitors by using co-crystal structural information from c-Met and VEGFR2 in complex with known inhibitors. This led to the identification of compounds 3a and 3b, which were capable of suppressing both c-Met and VEGFR2 kinase activities. Further optimization resulted in pyrazolone and pyridone derivatives, which could form intramolecular hydrogen bonds to enforce a rigid conformation, thereby producing potent inhibition. One compound of particular note was the imidazo[1,2-a]pyridine derivative (26) bearing a 6-methylpyridone ring, which strongly inhibited both c-Met and VEGFR2 enzyme activities (IC50 = 1.9, 2.2 nM), as well as proliferation of c-Met-addicted MKN45 cells and VEGF-stimulated human umbilical vein endothelial cells (IC50 = 5.0, 1.8 nM). Compound 26 exhibited dose-dependent antitumor efficacy in vivo in MKN45 (treated/control ratio [T/C] = 4%, po, 5 mg/kg, once-daily) and COLO205 (T/C = 13%, po, 15 mg/kg, once-daily) mouse xenograft models. 相似文献
118.
Lidiya Stavitskaya Michael J. Seminerio Jason R. Healy Bahar Noorbakhsh Rae R. Matsumoto Andrew Coop 《Bioorganic & medicinal chemistry》2013,21(17):4923-4927
A series of ring-constrained phenylpropyloxyethylamines, partial opioid structure analogs and derivatives of a previously studied sigma (σ) receptor ligand, was synthesized and evaluated at σ and opioid receptors for receptor selectivity. The results of this study identified several compounds with nanomolar affinity at both σ receptor subtypes. Compounds 6 and 9 had the highest selectivity for both σ receptor subtypes, compared to μ opioid receptors. In addition, compounds 6 and 9 significantly reduced the convulsive effects of cocaine in mice, which would be consistent with antagonism of σ receptors. 相似文献
119.
Atsuko Kushi Takashi Matsumoto Daisuke Yoshida 《Bioscience, biotechnology, and biochemistry》2013,77(9):1979-1982
A mutagenic fraction was separated by gas chromatography (gc) from the gaseous phase of protein pyrolyzate and a compound in the fraction was identified as hydrogen cyanide (hcn). Authentic hcn shows mutagenicity. It is proposed that most of the mutagenic activity in the gaseous phase of protein pyrolyzate is due to hcn. 相似文献
120.
Masao Fujimaki Makoto Tajima Teruyo Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(10):1228-1231
The free amino acids of potatoes irradiated with the doses of 7,000, 15,000 and 30,000 rad were determined by ion-exchange chromatography.After 15 days storage following irradiation, it was shown that the concentration of asparatic acid, proline and aliphatic amino acids increased with increasing irradiation doses, while that of basic amino acids and glutamic acid especially decreased. However, after 105 days of storage, the similarity of the free amino acid content of irradiated potatoes to that of non-irradiated and non-stored potatoes was observed.On the concentration of protein-bound amino acids, there were no significant differences between non-irradiated and 15,000 rad irradiated potatoes. 相似文献