PpINH1,an invertase inhibitor,interacts with vacuolar invertase PpVIN2 in regulating the chilling tolerance of peach fruit

Sucrose metabolism,particularly the decomposition of sucrose by invertase,plays a central role in plant responses to cold stress.Invertase inhibitors(INHs)evolved in higher plants as essential regulators of sucrose metabolism.By limiting invertase activity,INHs keep cellular sugar levels elevated,which provides enhanced protection to plants under stress.Our results showed that the expression of PpVIN2,the only vacuolar invertase(VIN)gene in peach fruit sensitive to chilling temperatures,increases significantly during cold storage,while VIN enzyme activity increases more modestly.We also found that peach fruit transiently overexpressing PpINH1 had decreased VIN activity.Interactions of PpINH1 and PpVIN2 with recombinant proteins were shown by yeast two-hybrid assays and bimolecular fluorescence complementation assays,as well as in vitro.During cold storage,trehalose-treated peach fruit had significantly increased PpINH1 expression,decreased VIN enzyme activity,and significantly higher sucrose content than did untreated fruit.As a result,the treated fruit had enhanced resistance to chilling injury.Collectively,our data show that the post-translational repression of VIN enzyme activity by PpINH1 helps maintain sucrose levels in peach fruit during cold storage,thereby improving resistance to chilling injury.

Infection of post-harvest peaches by Monilinia fructicola accelerates sucrose decomposition and stimulates the Embden–Meyerhof–Parnas pathway

To study the changes in sugar metabolism caused by fungal infection in post-harvest peaches,fruit from two cultivars(‘Baifeng’and‘Yulu’)was inoculated with Monilinia fructicola and stored at 10°C.During disease development,soluble sugar content was monitored,as well as the activities and expression of selected enzymes.Disease progression was accompanied by a decrease in sucrose content and increases in reducing sugars and soluble solids,consistent with higher enzyme activities for acid invertase,neutral invertase and sucrose synthase-cleavage,and lower activities for sucrose synthase-synthesis and sucrose phosphate synthase.Activities of phosphofructokinase,hexokinase,and pyruvate kinase,which are related to hexose metabolism,also increased.These changes stimulate the Embden–Meyerhof–Parnas(EMP)pathway.We conclude that the fungal disease in peach fruit accelerates the decomposition of sucrose,thereby providing more glucose as a substrate to the EMP pathway.

Carbon dots based on targeting unit inheritance strategy for Golgi apparatus-targeting imaging

The Golgi apparatus is one of the important organelles,where the final processing and packaging of cellular secretions(such as proteins)are completed.The disorder of Golgi apparatus structure and function will induce many diseases.Therefore,monitoring the morphological structure of Golgi apparatus is crucial for the diagnosis and treatment of relevant diseases.In order to achieve Golgi apparatus-targeting imaging,the strategy of targeting unit inheritance was adopted and carbon dots(CDs)with Golgi apparatus-targeting ability were synthesized by one-step hydrothermal method with L-ascorbic acid with high reactivity and reducibility as the carbon source and L-cysteine as the targeting unit.CDs have a certain amount of cysteine residues on their surface,and have excitation dependence,satisfactory fluorescence and cysteine residues stability and low toxicity.As an imaging agent,CDs can be used for targeting imaging of Golgi apparatus.

手性碳量子点的制备及其应用

手性碳量子点(CQDs)因兼具优异的荧光性质、良好的生物相容性、较低的毒性、易于功能化以及手性特征等,在催化、检测和生物医学等领域具有广阔的应用潜力。目前,通过一步法或两步法制备的手性CQDs,已应用于手性催化、手性检测、高尔基体靶向成像、选择性调控酶和蛋白活性、选择性调控细胞能量代谢和促进植物生长等领域。然而,手性CQDs的发展初露头角,需进一步完善可控合成工艺,制备高荧光量子产率的长波长手性CQDs,使其在生物医学等领域绽放异彩。

Green-emissive carbon quantum dots with high fluorescence quantum yield:Preparation and cell imaging

High fluorescence quantum yield(QY),excellent fluorescence stability,and low toxicity are essential for a good cellular imaging fluorescent probe.Green-emissive carbon quantum dots(CQDs)with many advantages,such as unique fluorescence properties,anti-photobleaching,low toxicity,fine biocompatibility and high penetration depth in tissues,have been considered as a potential candidate in cell imaging fluorescent probes.Herein,N,S-codoped green-emissive CQDs(QY=64.03%)were synthesized by the one-step hydrothermal method,with m-phenylenediamine as the carbon and nitrogen source,and L-cysteine as the nitrogen and sulfur dopant,under the optimum condition of 200℃ reaction for 2 h.Their luminescence was found to originate from the surface state.In light of the satisfactory photobleaching resistance and the low cytotoxicity,CQDs were used as a cell imaging probe for HeLa cell imaging.The results clearly indicate that cells can be labeled with CQDs,which can not only enter the cytoplasm,but also enter the nucleus through the nuclear pore,showing their broad application prospect in the field of cell imaging.