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61.
Toshiya Kamikado Ching-Fun Chang Shigeo Murakoshi Akira Sakurai Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(4):833-836
Two lignans were isolated from leaves of Magnolia kobus DC. as growth inhibitors on silkworm larvae and structurally elucidated as sesamin (I) and kobusin (II) which has been hitherto unknown. 相似文献
62.
A Transport System for C4-Dicarboxylic Acids in Isolated Membrane Preparations from Escherichia coli
Shigeo Murakawa Kazuo Izaki Hajime Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(8):1905-1914
To investigate the mechanism of succinate transport system in Escherichia coli, the isolated membranes were prepared from E. coli W2252 and T5, a mutant defective in succinate uptake derived from W2252. Uptakes of 14C-substrates by W2252 and T5 membranes and the dilution of accumulated radioactivity by unlabeled C4-dicarboxylic acids, indicated that C4-dicarboxylic acids in the tricarboxylic acid cycle are transported by the same system in E. coli which requires a suitable energy source such as NADH, D-lactate or reduced phenazine methosulfate. The uptakes of succinate by W2252 membranes were inhibited by an anaerobic incubation or some of the inhibitors of electron transport chain. Difference spectra of reduced versus oxidized membranes from W2252 and T5 indicated the reduction of flavoproteins and cytochromes by dithionite, NADH or D-lactate. From these results it was concluded that the uptake of the C4-dicarboxylic acids in isolated membranes is coupled to an electron transport chain involving a specific dehydrogenase system. 相似文献
63.
Sadao Kato Tadao Kurata Shigeo Ishiguro Masao Fujimaki 《Bioscience, biotechnology, and biochemistry》2013,77(7):1759-1761
Bacillus circulans WL-12, a yeast and fungal cell wall lytic bacterium, secretes a variety of polysaccharide degrading enzymes into the culture medium. When β-1,3-glucanase was induced with pachyman, a β-1,3-glucose polymer obtained from the tree fungus Poria cocus Wolf, six distinct active molecules of the enzyme with different molecular weights were detected in the culture supernatant of this bacterium. Molecular cloning of one of the β,3-gIucanase genes into E. coli was achieved by transforming E. coli HB101 cells with recombinant plasmids composed of chromosomal DNA fragments prepared from B. circulans WL-12 and the plasmid vector pUC 19. A recombinant plasmid containing 4.4 kb of inserted DNA in the Pst I site of pUC 19, designated as pNT003, conferred the ability to degrade pachyman on E. coli cells. The presence of pNT003 was harmful for E. coli cells and caused cell lysis, especially at higher temperatures of cultivation. β,3-Glucanase activity detected in E. coli was mainly recovered in the periplasmic fraction when cell lysis did not occur. SDS-PAGE analysis revealed that the periplasmic fraction contained four active molecules of β-1,3-glucanase which corresponded to four of the six active molecules produced by B. circulans WL-12. 相似文献
64.
65.
Emerging solar cells, namely, organic solar cells and perovskite solar cells, are the thin‐film photovoltaics that have light to electricity conversion efficiencies close to that of silicon solar cells while possessing advantages in having additional functionalities, facile‐processability, and low fabrication cost. To maximize these advantages, the electrode components must be replaced by materials that are more flexible and cost‐effective. Researchers around the globe have been looking for the new electrodes that meet these requirements. Among many candidates, single‐walled carbon nanotubes have demonstrated their feasibility as the new alternative to conventional electrodes, such as indium tin oxide and metals. This review discusses various growth methods of single‐walled carbon nanotubes and their electrode applications in thin‐film photovoltaics. 相似文献
66.
Yokoi H Shimada A Carl M Takashima S Kobayashi D Narita T Jindo T Kimura T Kitagawa T Kage T Sawada A Naruse K Asakawa S Shimizu N Mitani H Shima A Tsutsumi M Hori H Wittbrodt J Saga Y Ishikawa Y Araki K Takeda H 《Developmental biology》2007,304(1):326-337
Medaka (Oryzias latipes) is a small freshwater teleost that provides an excellent developmental genetic model complementary to zebrafish. Our recent mutagenesis screening using medaka identified headfish (hdf) which is characterized by the absence of trunk and tail structures with nearly normal head including the midbrain-hindbrain boundary (MHB). Positional-candidate cloning revealed that the hdf mutation causes a functionally null form of Fgfr1. The fgfr1hdf is thus the first fgf receptor mutant in fish. Although FGF signaling has been implicated in mesoderm induction, mesoderm is induced normally in the fgfr1hdf mutant, but subsequently, mutant embryos fail to maintain the mesoderm, leading to defects in mesoderm derivatives, especially in trunk and tail. Furthermore, we found that morpholino knockdown of medaka fgf8 resulted in a phenotype identical to the fgfr1hdf mutant, suggesting that like its mouse counterpart, Fgf8 is a major ligand for Fgfr1 in medaka early embryogenesis. Intriguingly, Fgf8 and Fgfr1 in zebrafish are also suggested to form a major ligand-receptor pair, but their function is much diverged, as the zebrafish fgfr1 morphant and zebrafish fgf8 mutant acerebellar (ace) only fail to develop the MHB, but develop nearly unaffected trunk and tail. These results provide evidence that teleost fish have evolved divergent functions of Fgf8-Fgfr1 while maintaining the ligand-receptor relationships. Comparative analysis using different fish is thus invaluable for shedding light on evolutionary diversification of gene function. 相似文献
67.
The olfactory epithelium (OE) is derived from the olfactory placode (OP) during mouse development. At embryonic day (E) 10.0-E10.5, “early neurogenesis” occurs in the OE, which includes production of pioneer neurons that emigrate out of the OE and other early-differentiated neurons. Around E12.5, the OE becomes organized into mature pseudostratified epithelium and shows “established neurogenesis,” in which olfactory receptor neurons (ORNs) are differentiated from basal progenitors. Little is known about the molecular pathway of early neurogenesis. The homeodomain protein Six1 is expressed in all OP cells and neurogenic precursors in the OE. Here we show that early neurogenesis is severely disturbed despite the unaltered expression of Mash1 at E10.5 in the Six1-deficient mice (Six1−/−). Expression levels of neurogenin1 (Ngn1) and NeuroD are reduced and those of Hes1 and Hes5 are augmented in the OE of Six1−/− at E10.5. Pioneer neurons and cellular aggregates, which are derived from the OP/OE and situated in the mesenchyme between the OE and forebrain, are completely absent in Six1−/−. Moreover, ORN axons and the gonadotropin-releasing hormone-positive neurons fail to extend and migrate to the forebrain, respectively. Our study indicates that Six1 plays critical roles in early neurogenesis by regulating Ngn1, NeuroD, Hes1, and Hes5. 相似文献
68.
Kudou D Misaki S Yamashita M Tamura T Takakura T Yoshioka T Yagi S Hoffman RM Takimoto A Esaki N Inagaki K 《Journal of biochemistry》2007,141(4):535-544
l-Methionine gamma-lyase (EC 4.4.1.11, MGL_Pp) from Pseudomonas putida is a multifunctional enzyme, which belongs to the gamma-family of pyridoxal-5'-phosphate (PLP) dependent enzymes. In this report, we demonstrate that the three-dimensional structure of MGL_Pp has been completely solved by the molecular replacement method to an R-factor of 20.4% at 1.8 A resolution. Detailed information of the overall structure of MGL_Pp supplies a clear picture of the substrate- and PLP-binding pockets. Tyr59 and Arg61 of neighbouring subunits, which are strongly conserved in other gamma-family enzymes, contact the phosphate group of PLP. These residues are important as the main anchor within the active site. Lys240, Asp241 and Arg61 of one partner monomer and Tyr114 and Cys116 of the other partner monomer form a hydrogen-bond network in the MGL active site which is specific for MGLs. It is also suggested that electrostatic interactions at the subunit interface are involved in the stabilization of the structural conformation. The detailed structure will facilitate the development of MGL_Pp as an anticancer drug. 相似文献
69.
Mimuro H Suzuki T Nagai S Rieder G Suzuki M Nagai T Fujita Y Nagamatsu K Ishijima N Koyasu S Haas R Sasakawa C 《Cell host & microbe》2007,2(4):250-263
Colonization of the gastric pits in the stomach by Helicobacter pylori (Hp) is a major risk factor for gastritis, gastric ulcers, and cancer. Normally, rapid self-renewal of gut epithelia, which occurs by a balance of progenitor proliferation and pit cell apoptosis, serves as a host defense mechanism to limit bacterial colonization. To investigate how Hp overcomes this host defense, we use the Mongolian gerbil model of Hp infection. Apoptotic loss of pit cells induced by a proapoptotic agent is suppressed by Hp. The ability of Hp to suppress apoptosis contributed to pit hyperplasia and persistent bacterial colonization of the stomach. Infection with WT Hp but not with a mutant in the virulence effector cagA increased levels of the prosurvival factor phospho-ERK and antiapoptotic protein MCL1 in the gastric pits. Thus, CagA activates host cell survival and antiapoptotic pathways to overcome self-renewal of the gastric epithelium and help sustain Hp infection. 相似文献
70.