VITAMINS
Online ISSN : 2424-080X
Print ISSN : 0006-386X
Volume 70, Issue 8
Displaying 1-23 of 23 articles from this issue
  • Article type: Cover
    1996 Volume 70 Issue 8 Pages Cover1-
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • Akira SHIBATA
    Article type: Article
    1996 Volume 70 Issue 8 Pages 359-367
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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    Proteins with covalently bound retinal, visual rhodopsin and bacteriorhodopsin, have different spectral forms due to the retinal-protein interactions and a "fine tuning" mechanism of maximal absorbance adjustment. Bacteriorhodopsin existing in the purple membrane contains seven transmembrane helices and is extremely stable membrane protein. The bacteriorhodopsin spectrum has been found to have a high responsiveness to stimulation by anesthetics. The effects of volatile anesthetics (Enflurane, Halothane and 1-alcohols) on the structure of bacteriorhodopsin in the purple membrane in solution were investigated with spectrophotometry. Enflurane shifted the maximum absorption of bacteriorhodopsin from 568 to 480 nm, while halothane and 1-alcohols, in a concentration dependent manner, induced a further shift from 480 to 380 nm. The 480 nm-form can be reverted to the original 568 nm-form by evaporation of the anesthetics. However, the shift from 480 to 380 nm was irreversible. The reversibility is essential for anesthesia. Next the structural stability of bacteriohodopsin in an ultra thin film as a sensitive layer of an anesthetic sensor was studied using a monolayer technique which utilizes the air-water interface as a field to allow amphiphilic molecules to orient and form a condensed monolayer film. The stability of a bacteriorhodopsin film on the water surface depends significantly on the incubation time until the start of film compression. The α-helical bR molecule in the purple membrane film is partially transformed into a β-sheet with an increase in incubation time and released retinal from the inside of the protein. This destabilization of the α-helical bacteriohodopsin monolayer films is depressed by the addition of small amounts (50 mM) of Cs^+ and I-- ions. The absorbance profile at 568 nm of a self-assembled bR film transferred on a quartz plate showed a reversible conversion in regard to "off" of the vapor flow of anesthetic. The bR with covalently bound retinal chromophore can be expected to serve as an anesthetic biosensor.
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  • Katsumi SHIBATA
    Article type: Article
    1996 Volume 70 Issue 8 Pages 369-382
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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    Vitamin niacin is biosynthesized from an essential amino acid tryptophan and one defines it as the conversion ratio of tryptophan to niacin. As a lot of tryptophan exists in the body, the pathway is very important because niacin can be efficiently supplied even when the body emergently needs niacin. Therefore, it is very important to know factors affecting the conversion ratio of tryptophan to niacin. The conversion ratio is calculated by the comparison of (sum of the urinary excretion of nicotinamide and its metabolites, N^1-methylnicotinamide, N^1-methyl-2-pyridone-5-carboxamide, and N^1-methyl-4-pyridone-3-carboxamide (mol/day) /tryptophan intake (mol/day). The conversion ratio is decreased with increasing with dietary protein levels when diets contain sufficient of protein, while, when rats are fed with low protein and tryptophan-limiting diets, the conversion ratio is the lowest. In the effects of fat, feeding diets containing unsaturated fatty acids increased the conversion ratio, while feeding diets containing saturated fatty acids did not affect. In the effects of carbohydrate, the conversion ratio was higher in diets containing starch than in diets containing sucrose.
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  • Article type: Appendix
    1996 Volume 70 Issue 8 Pages 383-386
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 387-388
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 388-389
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 389-390
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 390-391
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 391-392
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 392-393
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 393-394
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    Article type: Article
    1996 Volume 70 Issue 8 Pages 394-
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 394-395
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 395-396
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 396-397
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    Article type: Article
    1996 Volume 70 Issue 8 Pages 399-400
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 400-
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 401-403
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 403-404
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 404-405
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 405-407
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
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  • [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 407-408
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese]
    Article type: Article
    1996 Volume 70 Issue 8 Pages 408-409
    Published: August 25, 1996
    Released on J-STAGE: December 26, 2017
    JOURNAL FREE ACCESS
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