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61.
Michihiro Ito Ikuo Sato Masumi Ishizaka Shin-ichiro Yoshida Motoo Koitabashi Shigenobu Yoshida Seiya Tsushima 《Applied and environmental microbiology》2013,79(5):1619-1628
Deoxynivalenol (DON) is a natural toxin of fungi that cause Fusarium head blight disease of wheat and other small-grain cereals. DON accumulates in infected grains and promotes the spread of the infection on wheat, posing serious problems to grain production. The elucidation of DON-catabolic genes and enzymes in DON-degrading microbes will provide new approaches to decrease DON contamination. Here, we report a cytochrome P450 system capable of catabolizing DON in Sphingomonas sp. strain KSM1, a DON-utilizing bacterium newly isolated from lake water. The P450 gene ddnA was cloned through an activity-based screening of a KSM1 genomic library. The genes of its redox partner candidates (flavin adenine dinucleotide [FAD]-dependent ferredoxin reductase and mitochondrial-type [2Fe-2S] ferredoxin) were not found adjacent to ddnA; the redox partner candidates were further cloned separately based on conserved motifs. The DON-catabolic activity was reconstituted in vitro in an electron transfer chain comprising the three enzymes and NADH, with a catalytic efficiency (kcat/Km) of 6.4 mM−1 s−1. The reaction product was identified as 16-hydroxy-deoxynivalenol. A bioassay using wheat seedlings revealed that the hydroxylation dramatically reduced the toxicity of DON to wheat. The enzyme system showed similar catalytic efficiencies toward nivalenol and 3-acetyl deoxynivalenol, toxins that frequently cooccur with DON. These findings identify an enzyme system that catabolizes DON, leading to reduced phytotoxicity to wheat. 相似文献
62.
Takashi Akazawa Yasuichi Umemura Ikuzo Uritani 《Bioscience, biotechnology, and biochemistry》2013,77(3):192-196
It was shown in previous papers that in sweet potato infected with Ceratostomella fimbriata, there occurred metabolic activations such as respiratory increase, polyphenols production, protein synthesis and organic phosphate accumulation. In this report on an electrophoretic experiment, forming a part of those studies, it is stated that the pattern of the protein components in the sound part, adjacent to the infected part of sweet potato attacked by the pathogen differs from that of sound sweet potato. 相似文献
63.
Hajime Taniguchi Yasukiyo Umemura Michinori Nakamura 《Bioscience, biotechnology, and biochemistry》2013,77(2):231-239
The acid-soluble nucleotides were extracted from the tubers of Jerusalem artichoke with percbloric acid, and separated and purified by means of adsorption on and elution from active charcoal, repeated chromatography on columns of Dowex I (Cl-), followed by paper chromatography. The following nucleotides have been characterized and/or identified: 5′-AMP, 3′-AMP, ADP, ATP, 5′-GMP, 2′-GMP, 3′-GMP, 2′,3′-cyclic GMP, GDP, GTP, 5′-UMP, UDP, UTP, NADP, UDP-glucose, UDP-galactose, UDP-fructose, UDP-N-acetylhexosamine and GDP-mannose.** Neither cytosine ribonucleotides nor deoxyribonucleotides have been detected. The significance of these observations is discussed. 相似文献
64.
CENP-B interacts with CENP-C domains containing Mif2 regions responsible for centromere localization 总被引:10,自引:0,他引:10
Suzuki N Nakano M Nozaki N Egashira S Okazaki T Masumoto H 《The Journal of biological chemistry》2004,279(7):5934-5946
Recently, human artificial chromosomes featuring functional centromeres have been generated efficiently from naked synthetic alphoid DNA containing CENP-B boxes as a de novo mechanism in a human cultured cell line, but not from the synthetic alphoid DNA only containing mutations within CENP-B boxes, indicating that CENP-B has some functions in assembling centromere/kinetochore components on alphoid DNA. To investigate whether any interactions exist between CENP-B and the other centromere proteins, we screened a cDNA library by yeast two-hybrid analysis. An interaction between CENP-B and CENP-C was detected, and the CENP-C domains required were determined to overlap with three Mif2 homologous regions, which were also revealed to be involved in the CENP-C assembly of centromeres by expression of truncated polypeptides in cultured cells. Overproduction of truncated CENP-B containing no CENP-C interaction domains caused abnormal duplication of CENP-C domains at G2 and cell cycle delay at metaphase. These results suggest that the interaction between CENP-B and CENP-C may be involved in the correct assembly of CENP-C on alphoid DNA. In other words, a possible molecular linkage may exist between one of the kinetochore components and human centromere DNA through CENP-B/CENP-B box interaction. 相似文献
65.
Baudino L Shinohara Y Nimmerjahn F Furukawa J Nakata M Martínez-Soria E Petry F Ravetch JV Nishimura S Izui S 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(9):6664-6669
Replacement of aspartic acid by alanine at position 265 (D265A) in mouse IgG1 results in a complete loss of interaction between this isotype and low-affinity IgG Fc receptors (Fc gammaRIIB and Fc gammaRIII). However, it has not yet been defined whether the D265A substitution could exhibit similar effects on the interaction with two other Fc gammaR (Fc gammaRI and Fc gammaRIV) and on the activation of complement. To address this question, 34-3C anti-RBC IgG2a and IgG2b switch variants bearing the D265A mutation were generated, and their effector functions and in vivo pathogenicity were compared with those of the respective wild-type Abs. The introduction of the D265A mutation almost completely abolished the binding of 34-3C IgG2a and IgG2b to all four classes of Fc gammaR and the activation of complement. Consequently, these mutants were hardly pathogenic. Although oligosaccharide side chains of these mutants were found to contain higher levels of sialic acids than those of wild-type Abs, the analysis of enzymatically desialylated D265A variants ruled out the possibility that very poor Fc-associated effector functions of the D265A mutants were due to an increased level of the mutant Fc sialylation. Thus, our results demonstrate that aspartic acid at position 265 is a residue critically implicated in triggering the Fc-associated effector functions of IgG, probably by defining a crucial three-dimensional structure of the Fc region. 相似文献
66.
Ogawa S Tokumoto Y Miyake J Nagamune T 《In vitro cellular & developmental biology. Animal》2011,47(7):464-469
Induced pluripotent stem cells (iPSCs) prepared from somatic cells might become a novel therapeutic tool in regenerative medicine,
especially for the central nervous system (CNS). In this study, we attempted to induce O4-positive (O4+) oligodendrocytes from adult human fibroblast-derived iPSCs in vitro. We used two adult human iPSC cell lines, 201B7 and
253G1. 201B7 was induced by four-gene transduction (oct4, sox2, klf4, c-myc), and 253G1 was induced by three-gene transduction
(oct4, sox2, klf4). We treated these cells with two in vitro oligodendrocyte-directed differentiation protocols that were
optimized for human embryonic stem cells. One protocol used platelet-derived growth factor as the major mitogen for oligodendrocyte
lineage cells, and the other protocol used epidermal growth factor (EGF) as the mitogen. Although the differentiation efficiency
was low (less than 0.01%), we could induce O4+ oligodendrocytes from 253G1 cells using the EGF-dependent differentiation protocol. This is the first report of the in vitro
induction of oligodendrocytes differentiation from human iPSCs. 相似文献
67.
68.
Nobuhito Ikeuchi Akihiro Hosoi Makoto Kurachi Shin-ichiro Fujii Koji Matsushima Kazuhiro Kakimi 《Biochemical and biophysical research communications》2010,392(2):217-222
To develop a novel dendritic cell (DC)-based vaccine for inducing antigen-specific CD8+ T cell responses by cross-presentation, we tested a novel antigen delivery system that introduces soluble antigens into the cytosol of cells by an endocytosis-mediated mechanism which avoids damaging the plasma membrane (“Endo-Porter”™). Proteins released from endosomes into the cytoplasm are degraded by the proteasome, and fragmented antigenic peptides are presented to the classical cytosolic MHC class I pathway. DCs pulsed with OVA protein in the presence of Endo-Porter efficiently stimulate OVA peptide-specific CD8+ T (OT-I) cells. Although this agent diverts some of the endocytosed antigens away from the classical MHC class II-restricted presentation pathway to the class I pathway, the activation of CD4+ T cells was found not to be hampered by Endo-Porter-mediated antigen delivery. On the contrary, it was rather augmented, probably due to the increased uptake of antigen. Because specific CD4+ T cell help is required to license DCs for cross-priming, Endo-Porter-mediated antigen delivery is a promising approach for developing more efficient cancer vaccines targeting both CD4+ and CD8+ T cells. 相似文献
69.
70.
Teno N Miyake T Ehara T Irie O Sakaki J Ohmori O Gunji H Matsuura N Masuya K Hitomi Y Nonomura K Horiuchi M Gohda K Iwasaki A Umemura I Tada S Kometani M Iwasaki G Cowan-Jacob SW Missbach M Lattmann R Betschart C 《Bioorganic & medicinal chemistry letters》2007,17(22):6096-6100
Pyrrolopyrimidine, a novel scaffold, allows to adjust interactions within the S3 subsite of cathepsin K. The core intermediate 10 facilitated the P3 optimization and identified highly potent and selective cathepsin K inhibitors 11-20. 相似文献