The sweet taste receptors comprised of T1r2 and T1r3, sense glucose concentrations in the gastrointestine. While hyperglycemia was reported to decrease the T1R2 and T1R3 tanscript levels in healthy subjects, no change...The sweet taste receptors comprised of T1r2 and T1r3, sense glucose concentrations in the gastrointestine. While hyperglycemia was reported to decrease the T1R2 and T1R3 tanscript levels in healthy subjects, no change was observed in type 2 diabetes patients. We investigated which glucose level and nutrients affect those transcript levels in MIN 6 and primary cultured taste buds cells using quantitative Reverse Trancription Polymerase Chain Reaction. High glucose diminished T1r2 transcript levels in MIN 6 and primary cultured taste buds cells. Resveratrol and its analogue augmented transcript levels of T1r1 and T1r2 above normal levels in MIN 6 cells in the medium with 25 mM glucose. Adenine, but not guanine, augmented T1r2 transcript levels of MIN 6 cells in the medium with 25 mM glucose. These results imply that nutrients in meals could affect sweet taste sensitivity by modulating T1r2 transcript levels in response to blood glucose levels.展开更多
Isofloridoside (IF) is a naturally occurring galactosylglycerol compound with a refreshing sweet taste. It is found in red algae, where it acts as a photosynthetic intermediate. However, the mechanism by which IF elic...Isofloridoside (IF) is a naturally occurring galactosylglycerol compound with a refreshing sweet taste. It is found in red algae, where it acts as a photosynthetic intermediate. However, the mechanism by which IF elicits sweetness has not been determined. In this study, we investigate the interaction between IF and the sweet taste receptor T1R2/T1R3. We show that IF causes an increase in intracellular Ca2+ concentration and an increase in Erk phosphorylation in T1R2/T1R3-expressing HEK293T cells, indicating that IF interacts with T1R2/T1R3. IF also activates endogenously expressed T1R2/T1R3 in mouse small intestinal endocrine L-cells, and promotes the secretion of the incretin glucagon-like peptide-1 (GLP-1). In silico docking simulations of IF and T1R2/T1R3 predict that IF forms hydrogen bonds with Tyr103 in the extracellular Venus flytrap domain of T1R2. This result is consistent with the binding mode of many other sweet-tasting molecules. We found that IF have the potential as a new alternative sweetener.展开更多
根据基于方位特征(POC)方程的并联机构拓扑设计理论和方法,设计了一种可实现两平移一转动(2T1R)输出运动的半对称并联机构,并对该机构的方位特征集、自由度、耦合度3个主要拓扑特征进行了分析计算,表明该机构的耦合度为1。然后,基于序...根据基于方位特征(POC)方程的并联机构拓扑设计理论和方法,设计了一种可实现两平移一转动(2T1R)输出运动的半对称并联机构,并对该机构的方位特征集、自由度、耦合度3个主要拓扑特征进行了分析计算,表明该机构的耦合度为1。然后,基于序单开链(Single Open Chain,SOC)的运动学建模原理,求解了机构的位置正解,导出位置机构反解解析式;进一步根据导出的位置反解公式分析了该机构的工作空间及其转动能力,研究了机构发生奇异的条件;并对机构的速度及其加速度进行了仿真分析。最后,对机构应用于脚踝按摩仪的原理进行了分析。展开更多
文摘The sweet taste receptors comprised of T1r2 and T1r3, sense glucose concentrations in the gastrointestine. While hyperglycemia was reported to decrease the T1R2 and T1R3 tanscript levels in healthy subjects, no change was observed in type 2 diabetes patients. We investigated which glucose level and nutrients affect those transcript levels in MIN 6 and primary cultured taste buds cells using quantitative Reverse Trancription Polymerase Chain Reaction. High glucose diminished T1r2 transcript levels in MIN 6 and primary cultured taste buds cells. Resveratrol and its analogue augmented transcript levels of T1r1 and T1r2 above normal levels in MIN 6 cells in the medium with 25 mM glucose. Adenine, but not guanine, augmented T1r2 transcript levels of MIN 6 cells in the medium with 25 mM glucose. These results imply that nutrients in meals could affect sweet taste sensitivity by modulating T1r2 transcript levels in response to blood glucose levels.
基金supported in part by a Grant-in-Aid for Scientific Reaserch(C)20K05927 from JSPS KAKENHI,Japan.
文摘Isofloridoside (IF) is a naturally occurring galactosylglycerol compound with a refreshing sweet taste. It is found in red algae, where it acts as a photosynthetic intermediate. However, the mechanism by which IF elicits sweetness has not been determined. In this study, we investigate the interaction between IF and the sweet taste receptor T1R2/T1R3. We show that IF causes an increase in intracellular Ca2+ concentration and an increase in Erk phosphorylation in T1R2/T1R3-expressing HEK293T cells, indicating that IF interacts with T1R2/T1R3. IF also activates endogenously expressed T1R2/T1R3 in mouse small intestinal endocrine L-cells, and promotes the secretion of the incretin glucagon-like peptide-1 (GLP-1). In silico docking simulations of IF and T1R2/T1R3 predict that IF forms hydrogen bonds with Tyr103 in the extracellular Venus flytrap domain of T1R2. This result is consistent with the binding mode of many other sweet-tasting molecules. We found that IF have the potential as a new alternative sweetener.
文摘根据基于方位特征(POC)方程的并联机构拓扑设计理论和方法,设计了一种可实现两平移一转动(2T1R)输出运动的半对称并联机构,并对该机构的方位特征集、自由度、耦合度3个主要拓扑特征进行了分析计算,表明该机构的耦合度为1。然后,基于序单开链(Single Open Chain,SOC)的运动学建模原理,求解了机构的位置正解,导出位置机构反解解析式;进一步根据导出的位置反解公式分析了该机构的工作空间及其转动能力,研究了机构发生奇异的条件;并对机构的速度及其加速度进行了仿真分析。最后,对机构应用于脚踝按摩仪的原理进行了分析。
