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19 results on '"Ifuku, Ohji"'

6. Immunohistochemical survey of the distribution of epidermal melanoblasts and melanocytes during the development of UVB-induced pigmented spots

Author

Furuya, Rikako, Yoshida, Yuzo, Moro, Osamu, Tsunenaga, Makoto, Aoki, Hirofumi, Kishimoto, Jiro, Ifuku, Ohji, and Hirobe, Tomohisa

Subjects
integumentary system, sense organs, skin and connective tissue diseases
Abstract

Repeated exposures to ultraviolet B radiation (UVB) induce pigmented spots on dorsal skin of (HR-1 x HR/De) F1 hairless mouse. We showed previously that this mouse is suitable for studies of melanocyte function. To clarify the mechanism of development of pigmented spots induced by chronic UVB exposure. Weused light and fluorescence microscopy to quantify changes in thenumbers of differentiated melanocytes containing melanin pigments(MM) and melanoblasts/melanocytes immunohistochemically positive for tyrosinase-related protein (TRP)-1, TRP-2 (dopachrome tautomerase), and c-kit in epidermis during the development of pigmented spots in hairless mice chronically exposed to UVB (99 mJ/cm2, 3 times/week, 8 weeks). The change in the number of TRP-1-positive cells during chronic UVB exposure was similar to that of MM: both increased dramatically during the stage of acute pigmentation, then decreased sharply after cessation of UVB, concomitantly with depigmentation; subsequently they increased gradually with the development of pigmented spots. In contrast, after two UVB exposures, no c-kit-positive cells were detected, then the number gradually increased during UVB irradiation, and continued to increase after cessation of irradiation; TRP-2-positive cells showed a rather similar pattern, except that they did not disappear initially. Our results indicate that chronic UVB irradiation induces differentiation and proliferation of melanoblasts, followed by an increase of differentiated melanocytes, leading to the development of pigmented spots. The sequence of expression of markers appeared to be c-kit, TRP-2, TRP-1, and finally melanin, as it is during normal melanocyte differentiation.

Published
2009

8. Application of an Analog of 9, 10-ketol-octadecadienoic acid (KODA), Affected Flower Bud Formation and MdTFL1 and MdFT1 Gene Expressions in Apple Buds under Heavy-crop and Shade Conditions

Author

Kittikorn, Monrudee, primary, Okawa, Katsuya, additional, Ohara, Hitoshi, additional, Kondo, Satoru, additional, Kotoda, Nobuhiro, additional, Wada, Masato, additional, Yokoyama, Mineyuki, additional, Ifuku, Ohji, additional, Murata, Ariake, additional, and Watanabe, Naoharu, additional

Published
2013
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19. Origin of carbon atoms of biotin.

Author

Ifuku, Ohji, Miyaoka, Hiroaki, Koga, Nobuyoshi, Kishimoto, Jiro, Haze, Shin-ichirou, Wachi, Youji, and Kajiwara, Masahiro

Subjects
*BIOTIN, *COENZYMES, *BIOSYNTHESIS, *MOLECULAR spectroscopy
Abstract

The origin of the carbon atoms of pimeloyl-CoA, the earliest known precursor in the pathway of de novo biotin biosynthesis in Escherichia coli, was investigated by "C-NMR spectroscopy. In fermentation of the biotin-overproducing DRK332/pXBA312 strain of Escherichia coli (a repressor mutant carrying a biotin operon fragment in the plasmid), a high dose of L-alanine (8 gA) stimulated dethiobiotin and biotin accumulation. Although L-alanine is a known precursor of 7-keto8-aminopelargonic acid in biotin biosynthesis, the [SUP13]C-NMR spectrum of dethiobiotin showed that the C-3 of L-13-[SUP13]Clalanine was incorporated into not only the methyl carbon (C-9) but also alternate carbons (C-2, C-4, C-6) of the side chain, and these latter positions are the same as those labeled with D-[ll-[SUP13]Clglucose. These data indicate that L-alanine can act as an alternative carbon source, suggesting that acetyl-CoA is a possible precursor for pimeloyl-CoA synthesis. In accordance with this hypothesis, the C-1 of sodium (1-[SUP13]C)acetate and the C-2 of sodium (2-"C)acetate were incorporated into alternate carbons in the side chain of dethiobiotin, i.e., (C-I, C-3, C-5, C-7) and (C-I, C2, C-4, C-6), respectively. These results suggested firstly that in E. coli pimeloyl-CoA is biosynthesized from L-alanine and/or acetate via acetyl-CoA, but not via pimelic acid, which has been suggested as a biotin precursor in other species, and secondly that the carboxyl group of biotin originates from carbon dioxide produced through the tricarboxylic acid cycle. [ABSTRACT FROM AUTHOR]

Published
1994
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