Low environmental temperatures promote anthocyanin accumulation and fruit colouration by up-regulating the expression of genes involved in anthocyanin biosynthesis and regulation in many fruit trees. However, the molecular mechanism by which fruit trees regulate this process in response to low temperature (LT) remains largely unknown. In this study, the cold-induced bHLH transcription factor gene MdbHLH3 was isolated from an apple tree and was found to interact physically and specifically through two regions (amino acids 1-23 and 186-228) at the N terminus with the MYB partner MdMYB1 (allelic to MdMYB10). Subsequently, MdbHLH3 bound to the promoters of the anthocyanin biosynthesis genes MdDFR and MdUFGT and the regulatory gene MdMYB1 to activate their expression. Furthermore, the MdbHLH3 protein was post-translationally modified, possibly involving phosphorylation following exposure to LTs, which enhanced its promoter-binding capacity and transcription activity. Our results demonstrate the molecular mechanism by which MdbHLH3 regulates LT-induced anthocyanin accumulation and fruit colouration in apple.

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Background Adipokines are reported to participate in many common pathologic processes of glucose dysregulation, such as insulin resistance, β-cell dysfunction, and chronic inflammation. Objective To detect the concentrations of plasma asprosin in subjects with impaired glucose regulation (IGR) and newly diagnosed type 2 diabetes (nT2DM) and its relationship to parameters of glucose and lipid metabolism, insulin resistance, and pancreatic β-cell function. Methods 143 eligible participants were included and were divided into three groups including normal glucose regulation (NGR, n = 52), IGR (n = 40), and nT2DM group (n = 51). The intravenous glucose tolerance test (IVGTT) and clinical and biochemical parameters were measured in all participants. Results Plasma asprosin levels were higher in IGR (82.40 ± 91.06 ng/mL, P < 0.001) and nT2DM (73.25 ± 91.69 ng/mL, P < 0.001) groups compared with those in the NGR (16.22 ± 9.27 ng/mL) group, especially in IGR subjects. Correlation analysis showed that plasma asprosin levels were positively correlated with waist circumference (Wc), fasting plasma glucose (FPG), postchallenge plasma glucose (2hPG), HbA1c, triglyceride (TG), and homeostasis model assessment for insulin resistance (HOMA-IR) and negatively correlated with homeostasis model assessment for β-cell function (HOMA-β), area under the curve of the first-phase (0–10 min) insulin secretion (AUC), acute insulin response (AIR), and glucose disposition index (GDI) (all P < 0.05). Multiple logistical regression analyses revealed that plasma asprosin concentrations were significantly correlated with IGR and nT2DM after controlling for age, sex, BMI, and WHR. Conclusions Circulating asprosin might be a predictor of early diagnosis in DM and might be a potential therapeutic target for prediabetes and T2DM.

The discovery of a novel activation mode provided by organocatalysis is presented. It is demonstrated that the merger of optically active secondary amines and polyenals generates reactive trienamine intermediates, which readily participate in Diels-Alder reactions with different classes of dienophiles, hence, providing a facile entry to highly complex molecular frameworks with excellent stereocontrol. For the Diels-Alder reactions with 3-olefinic oxindoles, spirocyclic oxidoles are formed in high yields, and with enantioselectivities in the range of 94-98% ee. It is demonstrated, that some of these products can be transformed into the hexahydrofuro[2,3-b]indole fragment. The organocatalytic trienamine concept has been extended to also include Diels-Alder reactions of olefins substituted with cyanoacetates providing multifunctional cyclohexenes with three contiguous stereocenters in high yield and good stereocontrol. The novelty of this activation strategy lies within the perfect chirality relay over a distance of up to eight bonds. Moreover, we also present the first trienamine tandem reaction by combining trienamine catalysis with enamine activation. In addition to the experimental results, a detailed mechanistic survey is also provided including NMR spectroscopic studies and calculations of the reactive trienamine intermediates, rationalizing the origin of stereochemistry.

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A nurse management intervention combining an in-person visit, periodic phone calls, and home blood pressure monitoring over 9 months was associated with a statistically significant reduction in systolic, but not diastolic, blood pressure compared to usual care in a high risk population. Home blood pressure monitoring alone was no more effective than usual care.

Chiral Lewis basic tertiary amines or phosphines can enable properly modified Morita-Baylis-Hillman (MBH) adducts to undergo asymmetric allylic substitutions with a wide range of nucleophiles. In addition, assisted by a Brønsted base, chiral Lewis bases can also catalytically convert modified MBH adducts into allylic ylides, which can be engaged in a variety of asymmetric annulation reactions. This tutorial review will focus on such chiral Lewis base-catalysed asymmetric transformations of MBH adducts, especially those developed over the past five years, allowing for the rapid construction of densely functionalised chiral molecules with high levels of regio- and stereoselectivities.

In the first successful catalytic asymmetric Diels-Alder reaction in 1979, Koga and colleagues used a chiral aluminum complex as a Lewis acid catalyst, but since then, researchers have developed numerous catalytic systems for these reactions. By 2000, several chiral organic compounds, such as the salts of imidazolidinones or TADDOLs, emerged as robust catalysts in the asymmetric Diels-Alder reactions. According to frontier molecular orbital theory, most of these catalysts employ a LUMO-lowering strategy as a means of activating electron-deficient dienophiles. Only rarely do chiral catalysts take advantage of the alternative strategy of activating the HOMO. In this Account we will discuss the development of asymmetric Diels-Alder reactions based on the HOMO-raising effects of chiral amines. First, we show that enamine intermediates formed in situ between an amine catalyst and enolizable aliphatic aldehydes can act as electron-rich dienophiles in inverse-electron-demand Diels-Alder reactions. We describe the preparation of a variety of oxygen- or nitrogen-containing heterocycles with high optical purity. Then, we demonstrate that the dienamine species from α,β-unsaturated aldehydes can act either as electron-rich dienes in normal-electron-demand Diels-Alder reactions or as dienophiles in inverse-electron-demand Diels-Alder reactions. These reactions generally occur with high chemo-, regio-, and stereoselectivity. Finally, we introduce a new activation mode for Diels-Alder reactions, in which reactive trienamine intermediates derived from 2,4-dienals or even 2,4-dienones play a key role. Notably, we observe remarkable β,ε-regioselectivity and obtain excellent stereocontrol even at the very remote ε-reactive center-up to seven bonds away from the chiral center of the amine catalyst. These results demonstrate that a HOMO-activation strategy via aminocatalysis could become a significant tool in asymmetric Diels-Alder reactions. In addition, these reactions using enamine, dienamine, or trienamine intermediates produce a diverse array of densely functionalized cyclic scaffolds, which may serve as valuable structures in drug discovery and natural product synthesis.