The cell membrane is an important interface for communication with extracellular events, and incorporation of bioactive substances, such as antibodies and receptors, into the cell membrane may ...enhance the potential abilities of cells. Gene manipulation, chemical modification of membrane proteins, and cell surface painting using a GPI anchor have been performed to introduce substances into cell membranes. Furthermore, many lipid anchors have also been used to modify lipid membranes such as liposomes. In this study, we have focused on developing an easy and rapid method for anchoring of substances including macromolecular proteins into the membranes of living mammalian cells. We employed a single oleyl chain derivative coupled with hydrophilic poly(ethylene glycol) (PEG90, the ethyleneoxide (EO) unit is 90) to facilitate solubilization in water. This water‐soluble derivative was designated Biocompatible Anchor for Membrane (BAM). Some proteins (streptavidin, EGFP and an antibody) were coupled with BAM90 at the distal terminal of PEG and rapidly (within a few minutes) anchored into the membranes of various cells (NIH3T3, 32D, Ba/F3, hybridoma 9E10). However, the anchored BAM90 disappeared from the cell membranes within 4–5 h in serum‐free culture media, and moreover, the retention time of anchoring was shortened (1–2 h) in culture medium containing 10% FBS. We further prepared a dioleylphosphatidylethanolamine (DOPE)‐PEG derivative (DOPE‐BAM80, the EO unit is 80) as a double oleyl chain derivative for comparison with the single oleyl chain derivative, BAM90. The retention time of anchored DOPE‐BAM80 was longer than that of BAM90 and more than 8 h in culture media with and without 10% serum. Furthermore, the treatment time of DOPE‐BAM80 for anchoring was nearly as short (within a few minutes) as that of BAM90. In addition, both types of BAMs, BAM90 and DOPE‐BAM80, showed no cytotoxicity. Therefore, DOPE‐BAM80 is useful for protein anchoring to cells. Although the utilization of BAM90 is considered to be limited, it is expected to useful in restricted environments, for example, in tissues such as the cornea, peritoneum, bladder, and various mucosae, which are less exposed to serum. Thus, we suggest the possibility that both types of BAM can be applied to cell surface engineering.
Diameter-dependent annealing effects of X-ray-induced defects in single-walled carbon nanotubes (SWNTs) were studied by Raman scattering spectroscopy. We found that X- ray-induced defects were formed ...in thin SWNTs at higher density than that in thick SWNTs. The X-ray-induced defects, distant pairs of interstitials and vacancies (I-V), were eliminated by thermal annealing. The recovery temperature of the X-ray-induced defects in the thin SWNTs were higher than that of the thick ones, indicating the thermal stability of the defects in thinner SWNTs are higher. In order to simulate the annealing behaviours of the X-ray-induced defects in SWNTs with diameters of ∼0.9 and ∼1.4 nm, we suggested the competitive reactions of diffusion of interstitials, formation of close I-V pairs and their recombination. The simulated results showed that the reaction-rate constant of elimination of close I-V pairs is dependent on tube diameter, which is presumably derived from nano-structure effects of SWNTs.
The antidiabetic activity of Momordica charantia L. (Cucurbitaceae) was investigated in KK-Ay mice, an animal model with type 2 diabetes with hyperinsulinemia. The water extract of the fruit of ...Momordica charantia L. (MC) reduced the blood glucose of KK-Ay mice 3 weeks after oral administration (p<0.01) and also significantly lowered the serum insulin of KK-Ay mice under similar conditions (p<0.01). However, MC did not affect the blood glucose in normal mice. MC-treated KK-Ay mice blood glucose significantly decreased in an insulin tolerance test. Moreover, the muscle content of facilitative glucose transporter isoform 4 (GLUT4) protein content in the plasma membrane fraction from muscle significantly increased in the orally MC-treated mice when compared with that of the controls (p<0.01). These results suggest that the antidiabetic effect of MC is derived, at least in part, from a decrease in insulin resistance because of the increase of GLUT4 protein content in the plasma membrane of the muscle.
This paper describes a reactor for multistep syntheses via intermediates with improved selectivity of the desired product. This reactor is referred to as an assembled reactor. It consists of mixing, ...residence time, and heat exchange units. Connection of these units forms a module for a single reaction. Repeated joints of these modules enable the reactor to be used in multistep syntheses. Mixing and the heat transfer rate of the assembled reactor were evaluated. This reactor enabled rapid mixing under the total flow rates of more than 30 mL/min and heat transfer efficiency of the order of 10 K per 10 ms in the heat exchange of fluids with a temperature difference of 20–40 K. This reactor was also applied to the synthesis of bromobenzene via p‐bromophenyllithium and gave a product yield of more than 80 %.
A reactor for multistep syntheses via intermediates, referred to as an assembled reactor, is presented. This reactor consists of mixing, residence time, and heat exchange units. Connection of these units forms a module for a single reaction. Repeated joints of modules enable the use of this reactor in multistep syntheses.
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