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Volume 84, Issue 7
Displaying 1-8 of 8 articles from this issue
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Toshiaki WatanabeArticle type: Article
2010 Volume 84 Issue 7 Pages 301-312
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSBiotin is a water soluble vitamin which serves as a covalently bound coenzyme for various types of carboxylase and is involved in fatty acid synthesis, glucose and amino acid metabolism. Biotin is well distributed in various kinds of foods. Overt biotin deficiency rarely occurs spontaneously in animals. Clinical signs characteristic of biotin deficiency, such as dermatitis and alopecia, develop in humans and rodents. In the series of our studies, the importance of biotin for normal reproduction and the development of embryos and offspring was demonstrated in mammals and birds. Maternal baltin deficiency during gestation produces external malformations such as cleft palate, micromelia and micrognathia in mice. However, there are species and strain differences in the teratogenic effects of biotin deficiency. The effects of biotin deficiency on palatal development in mouse embryos were studied by culturing embryonic palates and palatal mesenchymal cells. The incidence of palatal fusion was increased to 30% when 10^<-8>M-10^<-6>M biotin was added to the medium. In the biotin-deficient state, the proliferative availability of mesenchymal cells was significantly lower after 2 weeks of culturing. The amount of biotinylated histories in the nuclei was also lower than in the control cells. Protein expression in adenosine diphosphate (ADP)-ribosylation factor 2 and α-crystallin may be down-regulated in the mesenchyme of the palatal processes.As for the bioavailability of biotin during gestation, a large amount of biotin was transported to palates and mandibles on dg 12-15 (day of gestation). However, the biotin excretion in urine decreased after dg 6 and the urinary concentration of 3-hydroxyisovaleric acid increased after dg 12. The requirement of biotin increased during gestation and embryonic development, resulting in a lack of biotin in dams. On the other hand, excessive biotin intake during gestation induced many kinds of external malformations such as micrognathia, micromelia and edema in mouse fetuses. Also spermatogenesis was blocked by the excessive biotin intake for the long term in growing male rats. In birds, biotin was supplied in large amounts to growing ovarian follicles, particularly just before ovulation. In the embryos, free biotin in the yolk increased shortly after fertilization. A large amount of free biotin was incorporated into the embryo at the age of the 3-4 day (day 3-4). The expression of biotin-dependent carboxylase was different in egg yolk and embryos. Acetyl-CoA carboxylase (ACC) activity increased in the egg yolk after day 2 and pyruvate carboxylase (PC) increased with the growth of the embryos. Also biotinidase activity showed its highest value on day 2. Thus, biotin supply to the embryo differed among embryonic growth stages and organs, suggesting its involvement in the formation of each tissue and organ. From our findings, it is apparent that biotin is an essential nutrient and plays a critical role in the embryonic development of mammals and birds, indicating that it is important to maintain proper biotin levels during gestation.View full abstractDownload PDF (2363K) -
Jun Yamauchi, Aoi Yamashita, Asuka Shiratori, Mariko Sekiguchi, Erina ...Article type: Article
2010 Volume 84 Issue 7 Pages 313-321
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSRetinol binding protein 4 (RBP4) is the transport protein that carries retinol in blood. RBP4 was recently described as a new adipokine that reduced insulin sensitivity. Although mice lacking glucose transporter 4 (GLUT4) in adipocytes enhance RBP4 gene expression, its molecular mechanisms are unknown. We demonstrate promoter analysis of RBP4 in 3T3-L1 adipocytes, using a stable knockdown of GLUT4 (G4KD-L1) by a lentiviral shRNA-mediated system. We found a GLUT4 knockdown-dependent transcriptional activation (G4KA) element 〜1.3kb upstream of the RBP4 promoter. Mutations within the G4KA sequence significantly reduced expression of the RBP4 promoter-reporter construct in G4KD-L1 cells. In a yeast one-hybrid screen of a G4KD-L1 cell cDNA library, using the G4KA element as bait, we identified subunits of 20 S proteasome, PSMB1 and PSMA4, as binding partners. In ChIP assays, both subunits bound to the G4KA element, however, only PSMB1 tightly bound in response to GLUT4 knockdown. PSMB1 RNA interference, but not PSMA4, significantly inhibited RBP4 transcription. Nuclear transportation of PSMB1 was increased in G4KD-L1. These results provide evidence for an exclusive proteasome subunit-related mechanism for transcriptional activation of RBP4 by GLUT4 knockdown.View full abstractDownload PDF (1308K) -
Michiko Nishioka, Fuki Kanosue, Yukinori Yabuta, Fumio WatanabeArticle type: Article
2010 Volume 84 Issue 7 Pages 322-324
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSVitamin B_<12> contents in skipjack tuna meats and internal organs were assayed by the microbiological method authorized in the standard tables of food composition in Japan (5th Revised and Enlarged Edition). The dark meat (chiai), heart, and liver contained substantial amounts (〜63.9μg/100g) of vitamin B_<12> relative to the other meats and organs. More than half (55.8%) of total vitamin B_<12> contents detected in the tested tissues were recovered in the dark meat. The results indicate that the skipjack dark meat is an excellent vitamin B_<12> source.View full abstractDownload PDF (511K) -
Tomoyuki Mishima, Yasuka Isa, Haruhito TsugeArticle type: Article
2010 Volume 84 Issue 7 Pages 325-327
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (470K) -
Akimori WadaArticle type: Article
2010 Volume 84 Issue 7 Pages 328-330
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (356K) -
Mariko ShinArticle type: Article
2010 Volume 84 Issue 7 Pages 331-334
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (654K) -
Shin Ogata, Hiroshi Taguchi, Chieri IdaArticle type: Article
2010 Volume 84 Issue 7 Pages 335-336
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (345K) -
Article type: Bibliography
2010 Volume 84 Issue 7 Pages 337-341
Published: July 25, 2010
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (549K)
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