Homeostasis of brassinosteroids (BRs) is essential for normal growth and development in higher plants. We examined responsiveness of 11 BR metabolic gene expressions to the decrease or increase of endogenous BR contents in Arabidopsis (Arabidopsis thaliana) to expand our knowledge of molecular mechanisms underlying BR homeostasis. Five BR-specific biosynthesis genes (DET2, DWF4, CPD, BR6ox1, and ROT3) and two sterol biosynthesis genes (FK and DWF5) were upregulated in BR-depleted wild-type plants grown under brassinazole, a BR biosynthesis inhibitor. On the other hand, in BRexcessive wild-type plants that were fed with brassinolide, four BR-specific synthesis genes (DWF4, CPD, BR6ox1, and ROT3) and a sterol synthesis gene (DWF7) were down-regulated and a BR inactivation gene (BAS1) was up-regulated. However, their response to fluctuation of BR levels was highly reduced (DWF4) or nullified (the other eight genes) in a bri1 mutant. Taken together, our results imply that BR homeostasis is maintained through feedback expressions of multiple genes, each of which is involved not only in BR-specific biosynthesis and inactivation, but also in sterol biosynthesis. Our results also indicate that their feedback expressions are under the control of a BRI1-mediated signaling pathway. Moreover, a weak response in the mutant suggests that DWF4 alone is likely to be regulated in other way(s) in addition to BRI1 mediation.
Variations in the fat-mass and obesity-associated gene (FTO) are associated with the obesity phenotype in many Caucasian populations. This association with the obesity phenotype is not clear in the Japanese. To investigate the relationship between the FTO gene and obesity in the Japanese, we genotyped single nucleotide polymorphisms (SNPs) in the FTO genes from severely obese subjects [n = 927, body mass index (BMI) C 30 kg/m 2 ] and normalweight control subjects (n = 1,527, BMI \ 25 kg/m 2 ).A case-control association analysis revealed that 15 SNPs, including rs9939609 and rs1121980, in a linkage disequilibrium (LD) block of approximately 50 kb demonstrated significant associations with obesity; rs1558902 was most significantly associated with obesity. P value in additive mode was 0.0000041, and odds ratio (OR) adjusted for age and gender was 1.41 [95% confidential interval (CI) = 1. rs1558902 genotype. Thus, the SNPs in the FTO gene were found to be associated with obesity, i.e., severe obesity, in the Japanese.
We compared the effects of 12-week programs of resistance training (RT), high-intensity interval aerobic training (HIAT), and moderate-intensity continuous aerobic training (MICT). The primary goal was to evaluate the therapeutic effects of the exercise modalities for the management of nonalcoholic fatty liver disease (NAFLD). A total of 61 sedentary obese men with NAFLD were randomized into one of the following exercise regimens (RT, HIAT, or MICT). Hepatic fat content was decreased to a similar extent in the RT, HIAT, and MICT groups (−14.3% vs. −13.7% vs. −14.3%) without significant changes in weight and visceral fat. The gene expression levels of fatty acid synthesis were significantly decreased in the subjects’ monocytes. Hepatic stiffness was decreased only in the HIAT group (−16.8%). The stiffness change was associated with restored Kupffer cell phagocytic function (+17.8%) and decreased levels of inflammation such as leptin (−13.2%) and ferritin (−14.1%). RT, HIAT, and MICT were equally effective in reducing hepatic fat content, but only HIAT was effective in improving hepatic stiffness and restoring Kupffer cell function. These benefits appeared to be independent of detectable weight and visceral fat reductions; the benefits were acquired through the modulation of in vivo fatty acid metabolism and obesity-related inflammatory conditions.
Our study revealed that V˙O2max improvement with the HIAT was greater than with the CAT despite the HIAT being performed with a far lower volume and in far less time than the CAT. This suggests that the HIAT has potential as a time-efficient training mode to improve V˙O2max in sedentary adults.
The antimutagenic activity of n-hexane extracts from eight strains of daikon (Raphanus sativus; Japanese white radish) have been examined using the UV-induced mutation assay of Escherichia coli B/r WP2. A correlation was found between the potency of antimutagenicity and the amount of 4-(methylthio)-3-butenyl isothiocyanate (MTBITC) in their n-hexane extracts. Because the pure MTBITC also showed antimutagenicity, MTBITC is presumably the active antimutagen principle in n-hexane extracts of daikon. Among the eight strains of daikon studied, Aokubi, the improved common strain in Japan, contained 71.0 micromol of MTBITC in 100 g of fresh daikon. In contrast, Karami and Momoyama, which are original wild strains, contained much more MTBITC (363.5 and 168.0 micromol/100 g, respectively). In addition, phenethyl isothiocyanate was found in a lesser amount (5-33 nmol/100 g) in eight strains of daikon, and allyl isothiocyanate and benzyl isothiocyanate were not detectable in any strains (<3 nmol/100 g). The amount of total isothiocyanate in grated daikon was 7.0 times higher than that in cut daikon measured after 30 min of cooking. Through eating habits, humans might be able to consume substantial amounts of the antimutagen MTBITC from dishes using the grated form of wild strains of daikon. Therefore, it is possible to substantially increase the intake of the antimutagenic ingredient of daikon (i.e., MTBITC) by changing food preferences and preparation procedures (i.e., using the grated form of the wild strains).
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