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71.
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
72.
Koichi Mitsukura Tatsuya Kuramoto Toyokazu Yoshida Norihiro Kimoto Hiroaki Yamamoto Toru Nagasawa 《Applied microbiology and biotechnology》2013,97(18):8079-8086
A NADPH-dependent (S)-imine reductase (SIR) was purified to be homogeneous from the cell-free extract of Streptomyces sp. GF3546. SIR appeared to be a homodimer protein with subunits of 30.5 kDa based on SDS-polyacrylamide gel electrophoresis and HPLC gel filtration. It also catalyzed the (S)-enantioselective reduction of not only 2-methyl-1-pyrroline (2-MPN) but also 1-methyl-3,4-dihydroisoquinoline and 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline. Specific activities for their imines were 130, 44, and 2.6 nmol?min?1?mg?1, and their optical purities were 92.7 % ee, 96.4 % ee, and >99 % ee, respectively. Using a NADPH-regenerating system, 10 mM 2-MPN was converted to amine with 100 % conversion and 92 % ee after 24 h. The amino acid sequence analysis revealed that SIR showed about 60 % identity to 6-phosphogluconate dehydrogenase. However, it showed only 37 % identity with Streptomyces sp. GF3587 (R)-imine reductase. Expression of SIR in Escherichia coli was achieved, and specific activity of the cell-free extract was about two times higher than that of the cell-free extract of Streptomyces sp. GF3546. 相似文献
73.
Naoyuki Kuwabara Dan Hu Hiroaki Tateno Hisayoshi Makyio Jun Hirabayashi Ryuichi Kato 《FEBS letters》2013
A fungal galectin from Agrocybe cylindracea (ACG) exhibits broad binding specificity for β-galactose–containing glycans. We determined the crystal structures of wild-type ACG and the N46A mutant, with and without glycan ligands. From these structures and a saccharide-binding analysis of the N46A mutant, we revealed that a conformational change of a unique insertion sequence containing Asn46 provides two binding modes for ACG, and thereby confers broad binding specificity. We propose that the unique sequence provides these two distinct glycan-binding modes by an induced-fit mechanism. 相似文献
74.
Ryo C. Yanagita Hiroaki Kamachi Masayuki Kikumori Harukuni Tokuda Nobutaka Suzuki Kiyotake Suenaga Hiroshi Nagai Kazuhiro Irie 《Bioorganic & medicinal chemistry letters》2013,23(15):4319-4323
Debromoaplysiatoxin (DAT) is a tumor promoter isolated from sea hare and exhibits anti-proliferative activity against several cancer cell lines. To clarify key residues that are responsible for its tumor-promoting activity, we focused on the chiral methoxy group in the side chain, whose role had not yet been discussed or examined before. Demethoxy-DAT (8) was derived from DAT and we evaluated its tumor-promoting activity, anti-proliferative activity, and ability to bind to protein kinase C (PKC) isozymes. Compound 8 showed somewhat weaker tumor-promoting activity than that of DAT both in vitro and in vivo, but showed higher anti-proliferative activity against several cancer cell lines. Although the affinity to novel PKC isozymes of 8 was comparable to that of DAT, the affinity to conventional PKC isozymes decreased slightly. These results suggest that the methoxy group of DAT is one of the key residues critical for tumor-promoting activity but not for anti-proliferative activity. Since the methoxy group has little influence on the molecular hydrophobicity, this is the first report showing that structural factors other than hydrophobicity in the side chain of DAT affected its biological activities. 相似文献
75.
Ryosuke Misu Shinya Oishi Shohei Setsuda Taro Noguchi Masato Kaneda Hiroaki Ohno Barry Evans Jean-Marc Navenot Stephen C. Peiper Nobutaka Fujii 《Bioorganic & medicinal chemistry letters》2013,23(9):2628-2631
Kisspeptins, endogenous peptide ligands for GPR54, play an important role in GnRH secretion. Since in vivo administration of kisspeptins induces increased plasma LH levels, GPR54 agonists hold promise as therapeutic agents for the treatment of hormonal secretion diseases. To facilitate the design of novel potent GPR54 ligands, residues in kisspeptins that involve in the interaction with GPR54 were investigated by kisspeptin-based photoaffinity probes. Herein, we report the design and synthesis of novel kisspeptin-based photoaffinity probes, and the application to crosslinking experiments for GPR54-expressing cells. 相似文献
76.
Li Zhu Tsuneyuki Tatsuke Hiroaki Mon Zhiqing Li Jian Xu Jae Man Lee Takahiro Kusakabe 《Insect biochemistry and molecular biology》2013,43(8):664-674
The Tudor-sn protein, which contains four staphylococcal nuclease domains and a Tudor domain, is a ubiquitous protein found in almost all organisms. It has been reported that Tudor-sn in mammals participates in various cellular pathways involved in gene regulation, cell growth, and development. In insects, we have previously identified a Tudor-sn ortholog in the silkworm, Bombyx mori, and detected its interactions between with Argonaute proteins. The role of Tudor-sn in silkworm, however, still remains largely unknown. In this study, we demonstrated that silkworm Tudor-sn is a stress granule (SG) protein, and determined its interactions with other SG proteins using Bimolecular Fluorescence Complementation assay and Insect Two-Hybrid method. Depletions of Argonaute proteins and SG-marker protein Tia1 by RNAi impaired the involvement of Tudor-sn in the SG formation. Protein domain deletion analysis of Tudor-sn demonstrated that SN2 is the key domain required for the aggregation of Tudor-sn in SGs. 相似文献
77.
Tsukasa Mizuhara Shinya Oishi Hiroaki Ohno Kazuya Shimura Masao Matsuoka Nobutaka Fujii 《Bioorganic & medicinal chemistry》2013,21(7):2079-2087
To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure–activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182. 相似文献
78.
Masaki Wakasugi Hiroaki Gouda Tomoyasu Hirose Akihiro Sugawara Tsuyoshi Yamamoto Kazuro Shiomi Toshiaki Sunazuka Satoshi Ōmura Shuichi Hirono 《Bioorganic & medicinal chemistry》2013,21(11):3214-3220
Human acidic mammalian chitinase (hAMCase) was recently shown to be involved in the development of asthma, suggesting a possible application for hAMCase inhibitors as novel therapeutic agents for asthma. We therefore initiated drug discovery research into hAMCase using a combination of in silico methodologies and a hAMCase assay system. We first selected 23 candidate hAMCase inhibitors from a database of four million compounds using a multistep screening system combining Tripos Topomer Search technology, a docking calculation and two-dimensional molecular similarity analysis. We then measured hAMCase inhibitory activity of the selected compounds and identified seven compounds with IC50 values ?100 μM. A model describing the binding modes of these hit compounds to hAMCase was constructed, and we discuss the structure–activity relationships of the compounds we identified, suggested by the model and the actual inhibitory activities of the compounds. 相似文献
79.
80.
Hiroaki Takahashi Yasunori Nara Katura Tuzimura 《Bioscience, biotechnology, and biochemistry》2013,77(12):2493-2494
Fluctuations of pungent principles of hot pepper fruits (capsaicinoid), chlorophylls, carotenoid, and fresh fruit weight in Capsicum annuum var. annuum cv. Karayatsubusa at different growth stages after flowering were examined. Capsaicinoid was first detected 20 days after flowering, and reached maximal level around 40 days after flowering, then later decreased gradually. The capsaicinoid composition did not show any appreciable change throughout the stages after flowering. CAP and DC were the major components in all of the stages examined. By using radioisotopic technique, it was found that the main formation and accumulation sites of capsaicinoid are in the placenta of the fruits. 相似文献