MEMBRANE
Online ISSN : 1884-6440
Print ISSN : 0385-1036
ISSN-L : 0385-1036
Volume 9, Issue 4
Displaying 1-5 of 5 articles from this issue
  • Freeze-Fracture Cytochemistry by Using a Sterol-Probe, Filipin
    Yasuo Kitajima, Takashi Sekiya, Yoshinori Nozawa
    1984 Volume 9 Issue 4 Pages 184-201
    Published: July 01, 1984
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    It has been widely accepted that biological membranes consist of the planar, biochemically and functionally specialized mosaics. One of the most important components to exert these planar domains in membranes is sterol, which can be visualized by using sterolprobes such as filipin and saponins.
    Filipin interacts with 3-β-hydroxysterols to produce 15-25nm protrusions or pits in membranes.These filipin-induced deformations of membranes can be detectable by electron microscopy of thin sections and freeze-fracture replicas, revealing the existence and topology of heterogenous sterol distribution in the membrane plane.
    In this article, the freeze-fracture method to detect the geometrical distribution of sterols in membranes using filipin for a sterol-probe, namely freeze-fracture cytochemistry or intramembranous cytochemistry, is reviewed from view points of method, interpletation and application. The possibility of “false-negative” in filipin-labeling is also described. Finally, some interesting cases in sterol-topology in membranes are presented, including dynamic functional mosaics in mast cells and myoblasts, and multiple domains in sperm, fungus and epidermis.
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  • P. C. Shukla
    1984 Volume 9 Issue 4 Pages 202-213
    Published: July 01, 1984
    Released on J-STAGE: August 16, 2011
    JOURNAL FREE ACCESS
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  • Atsuo Tanaka
    1984 Volume 9 Issue 4 Pages 215-224
    Published: July 01, 1984
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Of various immobilization methods developed hitherto, entrapment of biocatalysts in natural or synthetic polymer gels is the most promising because this method is applicable to immobilization not only of single enzymes but also of plural enzymes, cellular organelles, microbial cells, plant cells and animal cells. We have developed simple and convenient entrapment methods by using photo-crosslinkable resin prepolymers and urethane prepolymers of different chemical structures and physico-chemical properties. Gel-entrapped biocatalysts thus prepared have been successfully applied to the bioconversions of various compounds including lipophilic and water-insoluble compounds, and to the assays of different substances. Furthermore, entrapped living and growing microbial cells, which are used in multi-step and cooperative reactions, can be prepared by the prepolymer methods. Catalytic activities of the entrapped biocatalysts were proved to be affected by the physico-chemical properties of gels prepared from these prepolymers, such as net-work size, hydrophilicity-hydrophobicity balance and ionic nature. The prepolymer methods offer an easy selection of gel properties
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  • Masaru Horio, Yoshimasa Orita, Yoshifumi Fukuhara, Takeshi Nakanishi, ...
    1984 Volume 9 Issue 4 Pages 225-230
    Published: July 01, 1984
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Na+/H+ antiport was investigated in renal brush border membrane vesicles prepared from control and anhydro-4-epitetracycline-administered (100 mg/kg body weight) rabbits. Proton transport and resulting pH-gradient (ΔpH) across membrane were measured using acridine orange as a fluorescent probe. Our system to evaluate Na+/H+ antiport appeared to be consistent with previous descriptions on Na+/H+ antiporter in renal brush border membrane vesicles. We employed pH jump studies to measure initial ratesof H+ transport as a function of Na+ concentration. Kinetic analyses indicate that apparent KNa or Vmax in vesicles from anhydro-4-epitetracycline-administered rabbits was not significantly different from that in control (KNa=4.3±0.4 vs. 5.6±2.2 mM, Vmax=0.161±0.44 vs. 0.194±0.023 pH units/3s, respectively). These results support the conclusion that anhydro-4-epitetracycline dose not affect renal Na+/H+ antiporter.
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  • Kiyoshi Koyama, Masato Nishimura
    1984 Volume 9 Issue 4 Pages 231-235
    Published: July 01, 1984
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Reverse osmosis concentration of phenol in aqueous solution was examined by an interpolymer anionic composite membrane. The phenol concentration tests were carried out under applied pressure of 80kg/cm2 at 25°C. The rejection of phenol in undissociated state decreased with concentration of feed solution. On the other hand, the rejection in dissociated state was almost unchangeable until reverse osmosis concentration reached at ten times concentration ratio (X). The membrane showed higher rejection (90-95%) for phenol in dissociated state than the rejection for NaCl (90%). Therefore, reverse osmosis concentration may be possible to concentrate up to nine times of feed concentration of phenol. In undissociated state, the membrane showed lower rejection for phenol (39-62%) at 94% rejection level of NaCl, and concentration limit by reverse osmosis was at only two or three times of feed concentration.
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