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Volume 93, Issue 3
Displaying 1-6 of 6 articles from this issue
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Kimie Nakagawa2019 Volume 93 Issue 3 Pages 93-102
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSVitamin K is a fat-soluble vitamin that plays an important role in blood coagulation and bone formation. Vitamin K has homologues due to differences in the side chain structure, phylloquinone (abbreviated as vitamin K 1, PK) having a phytyl side chain and menaquinones (MK - n, n = 1 to 14) having an isoprenoid side chain structure. The main vitamin K that we take from our daily diet is PK, and a fermented food, natto, contains MK-7 produced by Bacillus subtilis natto . However, the majority of vitamin K present in the tissues of mammals including humans is menaquinone-4 (abbreviated as vitamin K 2, MK-4) having a geranylgeranyl side chain. This reason is that PK or MK-n obtained in the diet is converted into MK-4 in the body. This phenomenon has already been reported around 1960. However, the scientific proof that PK and MK-n are converted into MK-4 in vivo was not enough, so that the fact was not fully accepted. We scientifically proved for the first time that PK and MK-n are converted to MK-4 using stable isotope-labeled vitamin K. In 2010, we further identified that UbiA prenyltransferase domain containing protein 1 (UBIAD1) is responsible for the conversion reaction of PK and MK-n to MK-4 in vivo .
However, the physiological roles of MK-4 in all tissues of the whole body and the physiological significance of MK-4 converted from PK and MK-n by UBIAD1 have not been sufficiently elucidated yet. To investigate the function of UBIAD1 in vivo , we generated UBIAD1 systemic knockout mice and tissues-specific UBIAD1 knockout mice. In this paper, we introduce the findings of the mechanism that the transformation of MK-4 is caused by UBIAD1 and the physiological significance of this transformation which are based on our research.View full abstractDownload PDF (1113K) -
Natsuo Ueda2019 Volume 93 Issue 3 Pages 103-114
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSA large number of lipid molecules derived from phospholipids and fatty acids are known to function as endogenous signaling molecules and are collectively referred to as lipid mediators. Ethanolamides of long-chain fatty acids, called N-acylethanolamines, form a class of lipid mediators and include arachidonoylethanolamide (anandamide), palmitoylethanolamide, and oleoylethanolamide, which act as an endogenous agonist of cannabinoid receptors, an anti-inflammatory substance, and an appetitesuppressing substance, respectively. In mammalian tissues, N-acylethanolamines are formed from phosphatidylethanolamine (PE) via N-acyl-PE, a “triacyl-type” phospholipid, by the sequential catalyses of two enzymes, N-acyltransferase and N-acyl-PE-hydrolyzing phospholipase D (NAPE-PLD). We purified NAPE-PLD from rat heart and cloned its cDNA ahead of others in the world. We also found that a group of proteins showed Ca2+-independent N-acyltransferase activity and proposed to rename these proteins “phospholipase A/acyltransferase (PLAAT)-1–5”. As for the degradation pathway, N-acylethanolamines are hydrolyzed to free fatty acids and ethanolamine by fatty acid amide hydrolase. Our research group discovered a second enzyme catalyzing the same reaction and named the enzyme “N-acylethanolaminehydrolyzing acid amidase (NAAA)”. NAAA was a new lysosomal hydrolase abundantly expressed in macrophages and prostate. In this review, I discuss our longstanding efforts towards the discovery, cDNA cloning, and characterization of NAAA, NAPE-PLD, and PLAAT-1–5.View full abstractDownload PDF (1169K) -
Hirotaka Okuwa-Hayashi, Hiroshi Inui, Junko Inagaki, Masami Nakazawa, ...2019 Volume 93 Issue 3 Pages 115-122
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSEuglena is capable of growth under various variety of nutritional and environmental conditions. Euglena is possible to grow under diverse culture conditions with and without light illumination, namely under both heterotrophic and photoautotrophic conditions. Euglena can synthesize most of vitamins and biofactors except for the exception, such as vitamin B1 and B12. In the present study, the effects of nicotinamide and its analogues on the flagellar detachment of Euglena were investigated using nicotinamide and the 12 kinds of structural analogues (nicotinic acid, pyrazine, pyrazine-2-carboxylic acid, 2-picolinamide, methylnicotinate, N-methylnicotinamide, 3-methylpyridine, pyridine-3-sulfate, pyridoxine, pyridoxal, pyridoxamine, isonicotinic acid hydrazide), NAD+, and NADP+. Among these compounds, nicotinamide, nicotinic acid, pyrazine-2-carboxylic acid, methylnicotinate, 2-picolinamide, and N-methylnicotinamide caused the flagellar detachment and then cell division stopped. It was also found that when the nicotinamide added to Euglena cells was diluted with water or culture medium, cell division occurred and then flagella were regenerated after 24 h, resulting in the onset of euglenoid exercise. The electrophoresis of the detached flagellar proteins revealed that the proteins resembled tublin (55 kDa) and paraflagella rod 2 (69 kDa)View full abstractDownload PDF (1174K) -
Koichi Abe2019 Volume 93 Issue 3 Pages 123-127
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSThe system of “Foods with function claims (FFC)” in Japan has been launched in 2015. As of December 31, 2018, 1863 FFCs have been notified and received. Twentynine percentages of FFC-approved products (533 products) are for items to suppress the absorption of sugars and lipids,and improve the blood lipid profile. The remaining 71% are for items to help stress and sleep (201), to improve intestinal environment (195), to normalize blood pressure/blood flow/body temperature (180), to keep eye health (172), to improve memory capacity (137), and to keep skin health (125) and joint health (88). Analyzing functional materials, approximate 40% of them have anti-oxidant capacity. This review pinpoints recent trends of science and industry of FFC and the attaching points at issue.View full abstractDownload PDF (1099K) -
Takuyu Hashiguchi, Katsuhisa Kurogi, Masahito Suiko, Yoichi Sakakibara2019 Volume 93 Issue 3 Pages 128-132
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSDownload PDF (1023K) -
Hiroki Kakuta2019 Volume 93 Issue 3 Pages 133-136
Published: March 25, 2019
Released on J-STAGE: March 31, 2020
JOURNAL FREE ACCESSDownload PDF (885K)
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