著者
平岡 真実 香川 靖雄
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.89, no.2, pp.59-64, 2015-02-25 (Released:2017-08-10)

It is known that individuals respond differently to the same dietary intake differently. Nutrigenetics is an essential discipline to study gene-based differences in response to dietary components for nutrition and dietetics practice. One of the best-known examples for nutrigenetics is the polymorphism of methylenetetrahydrofolate reductase (MTHFR) C677T. The presence of the C677T mutation in MTHFR gene is associated with a reduction of MTHFR enzyme activity. This reduction of MTHFR enzyme activity may cause an increase in plasma homocysteine level which becomes risk factors for cardiovascular disease, cognitive impairment and neural tube defects. Plasma homocysteine level is responsive to intervention with folic acid and related vitamin B group. "Sakado Folate Projects" is a health promotion with personalized nutrition intervention based on MTHFR C677T polymorphisms for prevention of these diseases associated with hyperhomocysteinemia. An increase in serum folate level and a decrease in serum homocysteine level were observed at 4 months after the onset of this intervention and these changes were particularly marked in individuals with TT genotype. This finding suggests that personalized nutrition intervention based on genetic information is effective in motivating individuals to change their lifestyle habit.
著者
天野 晶子 石神 昭人
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.83, no.1, pp.24-26, 2009-01-25 (Released:2017-10-10)
参考文献数
21
被引用文献数
1
著者
槇島 誠
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.85, no.2, pp.47-56, 2011-02-25 (Released:2017-10-10)
参考文献数
51

Nuclear receptors belonging to the NR1H and NR1I subfamilies, including vitamin D receptor (VDR, NR1I1), control cholesterol and bile acid metabolism. Bile acids are detergents essential for the digestion and intestinal absorption of hydrophobic nutrients, such as triacylglycerol, cholesterol and lipid-soluble vitamins, including vitamin D.Primary bile acids are generated from cholesterol and are secreted in bile as glycine and taurine conjugates. The intestinal microflora convert the primary bile acids to the secondary bile acids, including lithocholic acid (LCA). VDR, a receptor for 1,25-dihydroxyvitamin D_3(1,25(OH)_2D_3), acts as a bile acid receptor with specificity for the secondary bile acid LCA and its derivatives. VDR activation by 1,25(OH)_2D_3 or LCA induces the xenobiotic metabolism of bile acids. Synthetic LCA derivatives induce tissue VDR activation without inducing hypercalcemia in mice. VDR acts as a bile acid sensor as well as an endocrine receptor for vitamin D signaling.
著者
井上 聡
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.83, no.2, pp.59-64, 2009-02-25 (Released:2017-10-10)
参考文献数
21

Vitamin K is a critical nutrient in the bone metabolism. We have demonstrated that SXR, a nuclear receptor steroid and xenobiotic receptor, expressed in bone cells could be activated by vitamin K_2 as a ligand. vitamin K_2 regulates the expression of various bone-related genes in osteoblastic cells. We have identified novel SXR targets that were up-regulated by vitamin K_2 in human osteoblastic cells. Tsukushi, a small leucine-rich repeat proteoglycan, has been shown to contribute to vitamin K-dependent collagen accumulation. Thus, we have discovered an alternative pathway of vitamin K action in the bone via transcriptional regulation utilizing nuclear receptor SXR.
著者
赤井 翔太 生城 浩子 澤井 大樹 林 秀行 神谷 信夫 宮原 郁子
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.88, no.7, pp.358-365, 2014

Homoserine dehydrogenase catalyzes the conversion of L-aspartate-4-semialdehyde to L-homoserine. Homoserine dehydrogenase is required for the biosynthesis of the three essential amino acids, i.e. lysine, methionine, and isoleucine, from aspartic acid. This enzyme attracts attention also as a promising antifungal drug target. We have determined the crystal structures of homoserine dehydrogenase from Thermus thermophilus HB8 in both substrate-free form and homoserine-binding form by X-ray diffraction. Crystallization conditions were surveyed at 293 K by using a hanging-drop vapor-diffusion method. The substrate-free form was solved to 1.4 Å resolution and the homoserine-binding form was solved to 2.0 Å resolution. The homoserine dehydrogenase was a dimer with each subunit composed of three distinct domains, nucleotide-binding, dimerization, and substrate-binding domain. In the homoserine-binding forms, the amino group of homoserine made a hydrogen bond to the side chain carboxylate of Glu180. This hydrogen bond induced the conformation change of Thr165-Pro183 loop, which made the loop close to the active site. The substrate homoserine was rigidly recognized by several amino acid residues in the enzyme active site, indicating that Lys99 or Lys195 would be an essential catalytic residue to facilitate hydride transfer.
著者
柴田 克已
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.71, no.11, pp.519-529, 1997-11-25 (Released:2018-04-07)
参考文献数
17
被引用文献数
1

Niacin is biosynthesized from tryptophan and its ability is enough to sustain the demand of niacin animal or human body. Therefore, niacin itself does not need to take. Vitamin B groups and minerals are required in the conversion of niacin from tryptophan. Thus, we investigated the effects of feeding with a thiamin-free, riboflavin-free, pyridoxine-free, or mineral-deficient diet on the conversion ratio of tryptophan to niacin in rats. In the thiamin-free experiment, the ratio was higher in the thiamin-free group than in the control. In riboflavin-deficient rats, the conversion ratio was not affected. In the pyridoxine-free experiment, the ratio was lower in the pyridoxine-free group than in the control. In the mineral-deficient experiment, the sum of the urinary excretion of nicotinamide and its metabolites was lower in a deficient group than in the control. Accordingly, deficiencies of pyridoxine and/or minerals directly caused niacin deficiency, but thiamin- and riboflavin-deficiencies did not.
著者
井上 裕康
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.78, no.12, pp.621-623, 2004-12-25 (Released:2017-10-10)
参考文献数
13

レスベラトロールは赤ワインに含まれる抗酸化作用を持つフィトアレキシン(抗菌性物質)である. レスベラトロールは中等度のワイン消費が心血管病, 脳卒中, 痴呆の危険度と負の相関を示す, いわゆる「フレンチパラドックス」に関与する物質と考えられてきた. 我々は最近, レスベラトロールが核内受容体PPAR(peroxisome proliferators activated receptor)αとPPARγを選択的に活性化すること, さらにPPARα活性化が脳保護効果をもたらすことを見いだした. これらの知見は「フレンチパラドックス」を説明する新しい作用機構を提供すると考えている. 一方で, レスベラトロールは寿命延長効果を持つカロリー制限模倣物質であること, オレイルエタノールアミドがPPARαの新しい内因性リガンドであり, その活性化によって食欲をコントロールすることが報告されている. そこでこれらの知見を含めて, 今後の展望とともに紹介したい.
著者
妹尾 春樹 畑 隆一郎
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.68, no.9, pp.501-513, 1994-09-25 (Released:2018-03-30)

Stellate cells (vitamin A-storing cells, lipocytes, fat-storing cells, Ito cells) exist in the perisinusoidal space of the hepatic lobule, and store 80% of retinoids in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. Under physiological conditions, these cells play key roles in the control of retinoid homeostasis ; they express specific receptors for retinol-binding protein (RBP), a binding protein specific for retinol, on their cell surface, and take up the complex of retinol and RBP by receptor-mediated endocytosis. Whereas, under pathological conditions such as liver cirrhosis, these cells lose retinoids, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. Morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts. ECM components regulate the morphology, proliferation, and functions of the stellate cells. L-ascorbic acid 2-phosphate, a long-acting vitamin C derivative, further modulates this cellular regulation by ECM components.