A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Structure,bioavailability and physicochemical properties of icariin-soymilk nanoparticle

Soymilk is a natural nanocarrier.However,the performance of flavonoid-soymilk nano-complex remains unclear.In this work,icariin-soymilk nano-complexes(ISNCs)were successfully fabricated and characterized.The effects of high-pressure homogenization(HPH)treatment on structure and physicochemical properties of soymilk and nano-complexes were investigated.HPH treatment could significantly improve the surface hydrophobicity and interfacial activity of soymilk.The soymilk with HPH treatment could significantly improve the water solubility(20 folds),thermal stability and bioavailability of icariin.The highest encapsulation efficiency(93.28%),loading capacity(39.09μg/mg),ζ-potentia(absolute value,31.20 mV)and bioavailability(72.14%)were observed in HSI-200(200 bar of homogenization pressure).While HSI-500(500 bar of homogenization pressure)showed the smallest particle size(183.73 nm).ISNCs showed a rougher surface and an irregular lamellar structure with large amount of fine particles by using Cryo-SEM,suggesting that icariin was encapsulated in soymilk.These data supplied a novel strategy to improve the performance of icariin in functional foods.

檀香木提取物对皮肤嗅觉受体的影响及功效

研究旨在探讨衰老对皮肤嗅觉受体OR2AT4的影响及檀香木提取物的作用机理和人体功效。通过不同年龄的体外重建表皮模型研究了年龄和OR2AT4的关系,并建立衰老表皮模型和毛囊真皮乳头细胞模型研究了檀香木提取物对OR2AT4的激活作用,通过毛囊真皮乳头细胞模型研究了檀香木提取物促进生长期延长因子IGF-1产生的作用。同时结合人体功效测试验证其抗衰老和防脱的功效。体外试验结果表明,OR2AT4的表达水平随年龄增加而减少。经1%檀香木提取物处理后,衰老表皮模型中的OR2AT4显著提升46%。同时,0.002%檀香木提取物作用于毛囊真皮乳头细胞时,可以促进IGF-1的产生,显著提升27%。临床试验结果表明,使用含2%檀香木提取物的面部乳霜28天后,皮肤水分含量、亮度、紧致度和皱纹均有所改善。使用含2%檀香木提取物的头皮精华86天后,头发密度显著提升。综上,檀香木提取物通过激活皮肤嗅觉受体改善皮肤衰老表征及防止因毛囊缺乏活力引起的脱发问题。

广藿香叶提取物的皮肤舒缓和修护功效研究

研究设计了3组基于不同皮肤刺激模型的人体测试,分别通过胶带剥脱法建立皮肤屏障物理性损伤模型,苯氧乙醇或辣椒素化学刺激原建立皮肤刺激模型,并结合主观自觉症状评分、客观非创仪器检测皮肤的生理学参数和光谱成像血流分析仪,系统性地研究了广藿香叶提取物对敏感性皮肤人群的临床皮肤舒缓和修护功效。结果表明,面膜中添加1%广藿香叶提取物可显著减轻苯氧乙醇引起的皮肤灼烧感和刺痛感(p<0.05)。使用含1%广藿香叶提取物乳霜30 min、1 h和2 h后,受损皮肤的经表皮失水率(TEWL)均显著减少(p<0.05),表明受损皮肤修复加速。通过TiVi 700图像可视化地比较和展示了1%广藿香叶提取物减轻皮肤红斑的效果。

短期氮处理(缺氧处理)对采后猕猴桃贮藏过程中抗氧化能力和质膜完整性的影响

将猕猴桃用氮气处理6 h后,在（1±1）℃、相对湿度为95%～100%条件下贮藏35 d,最后在20℃下放置3 d,测定果实硬度、质膜透性、硫代巴比妥酸反应产物（TBARS）、过氧化氢含量、超氧阴离子生成速率、脂氧合酶（LOX）、超氧化物歧化酶（SOD）和过氧化物酶（POD）的活性。

Mitogen-activated protein kinase 14-mediated phosphorylation of MaMYB4 negatively regulates banana fruit ripening

Mitogen-activated protein kinase(MAPK/MPK)cascades play crucial parts in plant growth,development processes,immune ability,and stress responses;however,the regulatory mechanism by which MAPK affects fruit ripening remains largely unexplored.Here,we reported that MaMPK14 cooperated with MaMYB4 to mediate postharvest banana fruit ripening.Transient overexpression of individual MaMPK14 and MaMYB4 in banana fruit delayed fruit ripening,confirming the negative roles in the ripening.The ripening negative regulator MaMYB4 could repress the transcription of genes associated with ethylene biosynthesis and fruit softening,such as MaACS1,MaXTH5,MaPG3,and MaEXPA15.Furthermore,MaMPK14 phosphorylated MaMYB4 at Ser160 via a direct interaction.Mutation at Ser160 of MaMYB4 reduced its interaction with MaMPK14 but did not affect its subcellular localization.Importantly,phosphorylation of MaMYB4 by MaMPK14 enhanced the MaMYB4-mediated transcriptional inhibition,binding strength,protein stability,and the repression of fruit ripening.Taken together,our results delineated the regulation pathway of MAPK module during banana fruit ripening,which involved the phosphorylation modification of MaMYB4 mediated by MaMPK14.

ATP homeostasis and signaling in plants

ATP is the primary form of energy for plants,and a shortage of cellular ATP is generally acknowledged to pose a threat to plant growth and development,stress resistance,and crop quality.The overall metabolic processes that contribute to the ATP pool,from production,dissipation,and transport to elimination,have been studied extensively.Considerable evidence has revealed that in addition to its role in energy supply,ATP also acts as a regulatory signaling molecule to activate global metabolic responses.Identification of the eATP receptor DORN1 contributed to a better understanding of how plants cope with disruption of ATP homeostasis and of the key points at which ATP signaling pathways intersect in cells or whole organisms.The functions of SnRK1a,the master regulator of the energy management network,in restoring the equi-librium of the ATP pool have been demonstrated,and the vast and complex metabolic network mediated by SnRK1a to adapt tofluctuating environments has been characterized.This paper reviews recent advances in understanding the regulatory control of the cellular ATP pool and discusses possible interactions among key regulators of ATP-pool homeostasis and crosstalk between iATP/eATP signaling pathways.Perception of ATP deficit and modulation of cellular ATP homeostasis mediated by SnRK1a in plants are discussed at the physiological and molecular levels.Finally,we suggest future research directions for modulation of plant cellular ATP homeostasis.

贮藏温度对鲜枸杞类胡萝卜素和氨基酸的影响及调控机制

本研究探讨了4和−4℃贮藏对鲜枸杞类胡萝卜素水平、类胡萝卜素合成、存储、降解相关基因以及氨基酸代谢相关基因表达的调控作用.结果表明,–4℃贮藏的枸杞果实中β-胡萝卜素、玉米黄素和玉米黄素双棕榈酸酯含量显著高于4℃,贮藏末期玉米黄素双棕榈酸酯含量比4℃贮藏高42.14%.枸杞果实低温贮藏过程中类胡萝卜素合成、存储和降解相关基因普遍上调表达,特别是类胡萝卜素裂解酶基因LbCCD4在贮藏过程中表达量升高超过70倍.4℃贮藏枸杞果实类胡萝卜素合成基因表达显著高于–4℃,但是存储蛋白基因LbHSP21、LbOR2表达极显著低于–4℃,降解酶基因LbNCED6、LbCCD1、LbCCD4则极显著高于–4℃,可能是导致其类胡萝卜素含量低于–4℃的主要原因.另一方面,4℃贮藏上调脯氨酸合成相关的LbOAT表达、维持脯氨酸降解相关的LbProDH在较低水平,从而有利于脯氨酸的积累.上述结果说明,–4℃贮藏更有利于枸杞类胡萝卜素的积累、保持较好的营养品质,并延缓果实衰老劣变.

Alternative splicing of MaMYB16L regulates starch degradation in banana fruit during ripening

The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains unclear.Here,we discovered that MaMYB16L,an R1-type MYB transcription factor,undergoes alternative splicing and generates two transcripts,the full-length isoform MaMYB16L and a truncated form MaMYB16S,in banana fruit.During banana fruit ripening,the alternative splicing process intensifies with downregulated MaMYB16L and upregulated MaMYB16S.Moreover,MaMYB16L is a transcriptional repressor that directly binds with the promoters of many genes associated with starch degradation and MaDREB2,a positive ripening regulator,and represses their expression.In contrast,MaMBY16S lacks a DNA-binding domain but competitively combines and forms non-functional heterodimers with functional MaMYB16L.MaMYB16L-MaMYB16S heterodimers decrease the binding capacity and transrepression activity of MaMYB16L.The downregulation of MaMYB16L and the upregulation of MaMYB16S,that is,a decreased ratio of active to non-active isoforms,facilitates the activation of ripening-related genes and thereby promotes fruit ripening.Furthermore,the transient overexpression of MaMYB16S promotes banana fruit ripening,whereas the overexpression of MaMYB16L delays this process.Therefore,the alternative splicing of MaMYB16L might generate a self-controlled regulatory loop to regulate banana fruit ripening.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

Pericarp browning is the major cause of deterioration of harvested litchi fruit.Water loss plays a role in pericarp browning of litchi fruit.This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature.Litchi fruit were stored in a non-humidified cold chamber(control)or in a humidified cold room using Tabor atomizer system that generated 95%relative humidity(RH)without depositing water on the fruit surface at 4℃.Control fruit stored in cold room without added humidity underwent rapid weight loss,accompanied by severe pericarp browning after 25 d of storage.However,slight weight loss and no obvious pericarp browning were found in humidified-fruit.Moreover,humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage.In addition,respiration rate was obviously inhibited in humidified-fruit compared with control fruit.This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film.

The thylakoid membrane protein NTA1 is an assembly factor of the cytochrome b6f complex essential for chloroplast development in Arabidopsis

The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new tiny albino 1(nta1)mutant in Arabidopsis,which has severe defects in Cyt b_(6f) accumulation and chloroplast development.Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene,NTA1,which encodes an integral thylakoid membrane protein conserved across green algae and plants.Overexpression of NTA1 completely rescued the nta1 phenotype,and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype.Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes,particularly the components of Cyt b_(6f).NTA1 was shown to directly interact with four subunits(Cyt b6/PetB,PetD,PetG,and PetN)of Cyt b_(6f) through the DUF1279 domain and C-terminal sequence to mediate their assembly.Taken together,our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b_(6f) complex by interacting with multiple Cyt b_(6f) subunits.

Nutraceutical potential of navel orange peel in diabetes management:The chemical profile,antioxidant,α-glucosidase inhibitory and antiglycation effects of its flavonoids

Oxidative damage,chronic hyperglycemia,and the formation of advanced glycation end products(AGEs)are important risk factors associated closely with diabetes and its complications.In the present study,the antidiabetic potential of navel orange peel was explored for the first time by evaluating the antioxidant,α-glucosidase inhibition,and antiglycation activities of its extracts and individual flavonoids.In total,seventeen flavonoids were identified from the peel extract,of which 5-hydroxy-6,7,3′,4′-tetramethoxyflavone,didymin and sinensetin were the most potent antioxidant,α-glucosidase inhibitor,and glycation inhibitor,respectively.In addition,the structure-activity relationship(SAR)studies of these flavonoids were performed in detail.Moreover,the most potent antidiabetic extract of navel orange peel was quantitatively analyzed by HPLC.The present results support the potent application of orange peel as a nutraceutical resource for diabetes management,and might be beneficial to the orange juice industry by providing useful information on the valorization of orange peel.

Transcription factor NOR and CNR synergistically regulate tomato fruit ripening and carotenoid biosynthesis

An expanding body of evidence has shown that NAC(NAM/ATAF1/2/CUC2)TF family plays crucial roles in regulating fruit ripening in both climacteric and non-cli-macteric fruits.In tomato,the NOR(NAC NON-RIPEN-ING)transcription factor has been identified as a master regulator of fruit ripening by activating the expression of genes involved in ethylene synthesis,cell wall degrada-tion,carotenoid biosynthesis,and the flavor formation(Gao et al.2020,2022).