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排序方式: 共有8784条查询结果,搜索用时 15 毫秒
1.
Kenji Tsuji Shinji KitamuraHirofumi Makino 《Biochemical and biophysical research communications》2014
The kidneys are exposed to hypoxic conditions during development. Hypoxia-inducible factor (HIF), an important mediator of the response to hypoxia, is believed to have an important role in development. However, the relationship between HIF and branching morphogenesis has not been elucidated clearly. 相似文献
2.
Takumi Higaki Natsumaro Kutsuna Kae Akita Hisako Takigawa-Imamura Kenji Yoshimura Takashi Miura 《PLoS computational biology》2016,12(4)
Plant leaf epidermal cells exhibit a jigsaw puzzle–like pattern that is generated by interdigitation of the cell wall during leaf development. The contribution of two ROP GTPases, ROP2 and ROP6, to the cytoskeletal dynamics that regulate epidermal cell wall interdigitation has already been examined; however, how interactions between these molecules result in pattern formation remains to be elucidated. Here, we propose a simple interface equation model that incorporates both the cell wall remodeling activity of ROP GTPases and the diffusible signaling molecules by which they are regulated. This model successfully reproduces pattern formation observed in vivo, and explains the counterintuitive experimental results of decreased cellulose production and increased thickness. Our model also reproduces the dynamics of three-way cell wall junctions. Therefore, this model provides a possible mechanism for cell wall interdigitation formation in vivo. 相似文献
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Qi-Wen Fan Kenji Kadomatsu Kenji Uchimura Takashi Muramatsu 《Development, growth & differentiation》1998,40(3):277-286
Embigin and basigin are highly glycosylated transmembrane glycoproteins with two immunoglobulin domains and form a subgroup in the immunoglobulin superfamily. Previous studies have demonstrated the functional significance of these molecules. In the present study, in situ hybridization analysis of their expression was performed during mouse embryogenesis. Embigin was strongly expressed in the endoderm during early postimplantation embryogenesis, and in the somite stage in the gut and visceral endoderm. Embryonic ectoderm and its derivative tissues weakly to moderately expressed this molecule. From day 10 to 15 of gestation, no embigin signal was detected. Basigin was more broadly expressed. During the organogenesis period, basigin was expressed in various epithelial tissues, brain ventricles, the spinal cord and dorsal root ganglion. The modes of expression of these two proteins throughout the egg cylinder stage correlated with the expression of the carbohydrate markers that they carry; embigin with Dolichos biflorus agglutinin binding sites and basigin with Lex antigen and more closely with fucosyltransferase IV, which forms the antigenic epitope. These findings imply that proteins with specific carbohydrate epitopes play roles in early postimplantation embryogenesis. 相似文献
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Refined corn bran (RCB), a dietary fiber derived from the mechanical refining of corn hulls, effectively adsorbed various environmental mutagens. When RCB was added at a concentration of 10 mg/ml to an aqueous solution of dinitropyrene (DNP), 91.6% of the mutagenicity towards Salmonella tester strain TA98 disappeared. Under similar conditions decreases in mutagenicity of DNP using wheat bran and cellulose powder were 58.4% and 43.0%, respectively. The adsorption of DNP to the fibers appeared irreversible since little mutagenicity was recovered by washing the treated fibers with aqueous buffer solutions of various pHs. Even with an organic solvent (methanol: ammonium hydroxide 50:1), only 2/3 of the mutagenicity of DNP was recovered. RCB could similarly adsorb mutagenic heterocyclic amines such as IQ, Trp-P-1, Trp-P-2, Glu-P-1, and Glu-P-2. 相似文献
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Cell walls were isolated by sonic disruption of log-phase cells of Clostridium botulinum type A strain 190L and purified by treatment with sodium dodecyl sulfate (SDS) followed by digestion with proteases. Electron microscopy revealed that the cell walls thus obtained were free of both cytoplasmic membrane and cytoplasmic fragments. The purified cell wall contained 8.7% total nitrogen, 15.0% total hexosamines, 22.4% reducing groups, 8.3% carbohydrate, and 3.1% glucose. The content of total phosphorus was very low (0.02%), and therefore it was expected that teichoic acid might be absent in the cell wall. The wall peptidoglycan contained glutamic acid, alanine, diaminopimelic acid, glucosamine and muramic acid in the molar ratios of 1.00:1.85:0:85:1.06:0.67. A low amount of galactosamine was also present, but no other amino acids were found in significant quantities. The SDS-treated cell walls were not attacked by lysozyme, but after extraction with hot formamide they were completely dissolved by the enzyme and released reducing groups. The lysozyme digest was separated into two constituents, the saccharide moiety and the peptide moiety on Sephadex G-50. 相似文献
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Larisa R. G. DeSantis Jessica R. Scott Blaine W. Schubert Shelly L. Donohue Brian M. McCray Courtney A. Van Stolk Amanda A. Winburn Michael A. Greshko Mackie C. O’Hara 《PloS one》2013,8(8)
The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately. 相似文献