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61.
Saiko Sugawara Toshihiko Ito Shiori Sato Yuki Sato Kano Kasuga Ikuo Kojima Masayuki Kobayashi 《Applied biochemistry and biotechnology》2014,172(1):206-215
Fibroblast growth factor 4 (FGF4) is considered as a crucial gene for tumorigenesis in humans and the development of mammalian embryos. The secreted, mature form of human FGF4 is thought to be comprised of 175 amino acid residues (proline32 to leucine206, Pro32-Leu206). Here, we found that bacterially expressed, 6× histidine (His)-tagged human FGF4 (Pro32-Leu206) protein, referred to as HishFGF4, was unstable such as in phosphate-buffered saline. In these conditions, site-specific cleavage, including between Ser54 and Leu55, in HishFGF4 was identified. In order to generate stable human FGF4 derivatives, a 6× His-tagged human FGF4 (Leu55-Leu206), termed HishFGF4L, was expressed in Escherichia coli. HishFGF4L could be purified from the supernatant of cell lysates by heparin column chromatography. In phosphate-buffered saline, HishFGF4L was considered as sufficiently stable. HishFGF4L exerted significant mitogenic activities in mouse embryonic fibroblast Balb/c 3T3 cells. In the presence of PD173074, an FGF receptor inhibitor, the growth-stimulating activity of HishFGF4L disappeared. Taken together, we suggest that HishFGF4L is capable of promoting cell growth via an authentic FGF signaling pathway. Our study provides a simple method for the production of a bioactive human FGF4 derivative in E. coli. 相似文献
62.
Kazuharu Sugawara Sora Ishizaki Hideki Kuramitz Toshihiko Kadoya 《Electroanalysis》2020,32(2):207-216
We developed a highly sensitive electrochemical system for the sensing of ovalbumin (OVA). Lysozyme origin/tyrosine‐rich peptides (RNRCKGTDVQAWY4C) were immobilized on magnetic beads, and the competitive reaction between OVA and oligothreonine/OVA origin peptide probe (T8VLLPDEVSG) could then be measured. In a previous study, the detection of OVA at the 10?13 M level was achieved using RNRCKGTDVQAWY4C‐modified beads via a cross‐linker. To improve the sensitivity to OVA, this system uses T8VLLPDEVSG peptide probe to measure the interaction to RNRCKGTDVQAWY4C immobilized on magnetic beads. The peak of Y4C actually was an electron‐transfer peptide, which represented the oxidation of a phenolic hydroxyl group. First, we confirmed that the oxidation response of Y4C was increased based on an improvement in the electron transfer accessibility by oligothreonine. Next, T8VLLPDEVSG peptide probe was used for the electrochemical sensing of OVA in solutions that contained consistent amounts of RNRCKGTDVQAWY4C on magnetic beads. As a result, the peak current decreased as the concentration of OVA increased. The sensitivity to OVA was improved compared with the use of only RNRCKGTDVQAWY4C on magnetic beads. The OVA detection level was 10?14 M, which approximates the results from antibody‐antigen reactions. Consequently, the proposed system is a powerful new concept in protein sensing. 相似文献
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Summary In order to investigate the kinetics of CO2dissociation on supported nickel catalysts, a novel technique, which can give the surface reaction rate constants with no
information on the number of active sites, was developed. It was revealed that CO2dissociation was more enhanced on TiO2support than on other metal oxide ones. The activity pattern and activation energies were in good agreement with those obtained
by a conventional pulse technique using the number of active sites, suggesting the validity of the present technique for investigating
the kinetics of the surface reaction.</o:p> 相似文献
67.
Koutaro Shiraishi Hironobu Koseki Toshiyuki Tsurumoto Koumei Baba Mariko Naito Koji Nakayama Hiroyuki Shindo 《Surface and interface analysis : SIA》2009,41(1):17-22
Photocatalysis with anatase Titanium dioxide (TiO2) under ultraviolet A (UVA) has a well recognized bactericidal effect. There have been a few reports, however, on the effects of photocatalysis on bio‐implant‐related infections. The purpose of present study was to evaluate the photocatalytic bactericidal effects of anatase TiO2 on Staphylococcus aureus (S. aureus) associated with surgical site infections. TiO2 films were synthesized on commercially pure titanium substrates and SUS316 stainless steel using a plasma source ion implantation method followed by annealing. The chemical composition of the surface layers was determined using GXRD and XPS. The disks were seeded with cultured S. aureus and exposed to UVA illumination from black light. The bactericidal effect of the TiO2 films was evaluated by counting the survived colonies statistically. A structural gradient anatase type TiO2 layer formed on all substrates. The viability of the bacteria on the photocatalytic TiO2 film coated on titanium was suppressed to 7.0% at 30 minutes and 5.5% at 45 minutes, whereas that on a similarly coated stainless steel was suppressed to 45.8% at 30 minute and 28.6% at 45 minutes (ANOVA: p < 0.05). Complete bacterial inactivation was achieved after 90 minutes on titanium and after 60 minutes on stainless steel. The photocatalytic bactericidal effect of TiO2 is useful for sterilizing the contaminated surfaces of bioimplants. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
68.
Tomohiro Takano Chutiparn Lertvachirapaiboon Yasuo Ohdaira Akira Baba Keizo Kato 《Molecular Crystals and Liquid Crystals》2019,685(1):93-99
AbstractGas sensing by using the transmission surface plasmon resonance (T-SPR) technique was demonstrated. Polyacrylic acid (PAA)/5-nm-thick gold/40-nm-thick silver/polycarbonate grating substrate structure (Sensor A) responded to ammonia; however, it exhibited a strong humidity dependence. Polyvinyl alcohol (PVA)/5-nm-thick gold/40-nm-thick silver/polycarbonate grating substrate structure (Sensor B) as the sensing material was also prepared and it mainly responded to humidity. The T-SPR properties of Sensors A and B were observed simultaneously by a stacking arrangement that enabled us to obtain the responses by using a single spectrophotometer. The ammonia concentration under various humidity conditions could be accurately obtained by simultaneous measurement of Sensors A and B. 相似文献
69.
Naoki Kise Yosei Takenaga Yohei Ishikawa Yoichi Morikami Toshihiko Sakurai 《Tetrahedron letters》2012,53(15):1940-1945
The reductive coupling of N-methoxycarbonyl lactams with benzophenone by Zn-TiCl4 in THF gave cross-coupled products as cyclic α-diphenylidene-N-methoxycarbonylamines and ring-opening α,α-diphenyl-α-hydroxy-ω-(N-methoxycarbonyl)amino ketones selectively depending on the reduction conditions. The reductive coupling of N-methoxycarbonyl lactams with 9-fluorenone by Zn-TiCl4 gave cyclic α-(9H-fluoren-9-ylidene)-N-methoxycarbonylamines preferentially irrespective to the conditions. 相似文献
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