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The aim of this work was to investigate the effects of black adzuki bean (BAB) extract on adipocytes, and to elucidate the cellular mechanisms. In order to examine the proliferation of preadipocytes and differentiating adipocytes, cell viability and DNA content were measured over a period of time. Lipid accumulation during cell differentiation and the molecular mechanisms underlying the effects of BAB on the transcriptional factors involved, with their anti-adipogenic effects, were also identified. We observed that BAB exhibits anti-adipogenic effects through the inhibition of proliferation, thereby lowering mRNA expression of C/EBPβ and suppressing adipogenesis during the early stage of differentiation. This, in turn, resulted in a reduction of TG accumulation in a dose- and time-dependent manner. Treating the cells with BAB not only suppressed the adipogenesis-associated key transcription factors PPARγ and C/EBPα but also significantly decreased the mRNA expression of GLUT4, FABP4, LPL and adiponectin. The expression of lipolytic genes like ATGL and HSL were higher in the treatment group than in the control. Overall, the black adzuki bean extract demonstrated an anti-adipogenic property, which makes it a potential dietary supplement for attenuation of obesity.

Legume-Rhizobium spp. symbiosis requires signaling between the symbiotic partners and differential expression of plant genes during nodule development. Previously, we cloned a gene encoding a putative b-carotene hydroxylase (GmBCH1) from soybean (Glycine max) whose expression increased during nodulation with Bradyrhizobium japonicum. In this work, we extended our study to three GmBCHs to examine their possible role(s) in nodule development, as they were additionally identified as nodule specific, along with the completion of the soybean genome. In situ hybridization revealed the expression of three GmBCHs (GmBCH1, GmBCH2, and GmBCH3) in the infected cells of root nodules, and their enzymatic activities were confirmed by functional assays in Escherichia coli. Localization of GmBCHs by transfecting Arabidopsis (Arabidopsis thaliana) protoplasts with green fluorescent protein fusions and by electron microscopic immunogold detection in soybean nodules indicated that GmBCH2 and GmBCH3 were present in plastids, while GmBCH1 appeared to be cytosolic. RNA interference of the GmBCHs severely impaired nitrogen fixation as well as nodule development. Surprisingly, we failed to detect zeaxanthin, a product of GmBCH, or any other carotenoids in nodules. Therefore, we examined the possibility that most of the carotenoids in nodules are converted or cleaved to other compounds. We detected the expression of some carotenoid cleavage dioxygenases (GmCCDs) in wild-type nodules and also a reduced amount of zeaxanthin in GmCCD8-expressing E. coli, suggesting cleavage of the carotenoid. In view of these findings, we propose that carotenoids such as zeaxanthin synthesized in root nodules are cleaved by GmCCDs, and we discuss the possible roles of the carotenoid cleavage products in nodulation.

BackgroundObesity is often considered to result from either excessive food intake or insufficient physical activity. Adzuki beans have been evaluated as potential remedies for various health conditions, and recent studies have reported their effects on the regulation of lipid metabolism, but it remains to be determined whether they may be effective in overcoming obesity by regulating appetite and satiety.ObjectiveThis study investigated the effect of black adzuki bean (BAB) extract on body composition and hypothalamic neuropeptide expression in Sprague Dawley rats (Rattus norvegicus) fed a high-fat diet.DesignThe rats were fed for 8 weeks with a control diet containing 10 kcal% from fat (CD), a high-fat diet containing 60 kcal% from fat (HD), or a high-fat diet with 1% or 2% freeze-dried ethanolic extract powder of BAB (BAB-1 and BAB-2).ResultsThe body weights and epididymal fat weights were significantly reduced and the serum lipid profiles were improved in the group fed the diet containing BAB compared to the HD group. The expression of AGRP mRNA significantly decreased in the BAB groups, and treatment with BAB-2 resulted in a marked induction of the mRNA expression of POMC and CART, which are anorexigenic neuropeptides that suppress food intake. Furthermore, mRNA expression levels of ObRb, a gene related to leptin sensitivity in the hypothalamus, were significantly higher in the BAB groups than in the HD group.ConclusionsThese results suggest that supplementation with BAB has a significant effect on body weight via regulation of hypothalamic neuropeptides.

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