低氧联合酸胁迫红小豆/绿豆萌发富集GABA及富含GABA芽豆复配米饭的工艺优化

为了研究低氧联合酸胁迫对红小豆和绿豆GABA富集的作用,采用单因素对萌发时间、萌发温度、低氧时间和L-谷氨酸浓度进行考察,在确定高GABA芽豆的胁迫条件基础上,将富含GABA红小豆、绿豆与大米进行复配,利用D-混料设计优化芽豆米饭配方工艺。结果显示,低氧联合酸胁迫对红小豆、绿豆富集GABA有积极促进作用,在萌发时间48 h、萌发温度40℃、低氧时间15 h和L-谷氨酸浓度2.5 mg/mL条件下,萌发红小豆中GABA高达158.32±3.24 mg/100 g。绿豆胁迫条件为萌发时间24 h、萌发温度35℃、低氧时间15 h和L-谷氨酸浓度2.5 mg/mL时,其中GABA含量最高为141.57±4.35 mg/100 g。在此基础上,通过D-混料设计优化确定了复配芽豆米饭的最佳配方为:大米76%、萌发绿豆11%、萌发红小豆13%,此条件下,芽豆米饭GABA含量为23.73±1.03 mg/100 g,感官评分均值为88.76±2.47,制得的芽豆米饭口感、色泽、香味均在可接受范围内,且积累了GABA活性成分,提升了芽豆米饭的营养及功能特性,为进一步开发杂粮复配米饭提供理论参考。

自拟平衡针灸通过调控PI3K-AKT信号通路及血清GABA水平对老年失眠的治疗作用

目的探讨自拟平衡针灸通过调控磷脂酰肌醇3激酶(PI3K)-蛋白激酶B(AKT)信号通路及血清氨基丁酸(GABA)水平对老年失眠的治疗作用。方法以老年失眠患者120例作为研究对象,按照随机分组原则分为研究组及对照组,各60例。两组均采取阿普唑仑进行治疗,研究组在此基础上联合采取自拟平衡针灸进行治疗,两组均治疗4 w。比较两组治疗效果、临床改善指标、PI3K-AKT信号通路及GABA、多导睡眠监测仪指标、睡眠质量之间的差异。结果研究组治疗总有效率显著高于对照组(P<0.05)。治疗后,两组睡眠潜伏期、睡眠总时间及觉醒次数均显著改善,且研究组睡眠潜伏期、觉醒次数显著低于对照组(P<0.05),睡眠总时间显著高于对照组(P<0.05)。两组PI3K、AKT及GABA均显著改善,且研究组PI3K、AKT显著低于对照组,GABA显著高于对照组(P<0.05)。两组总睡眠时间(TST)、睡眠效率(SE),第一(TS1)、二(TS2)、三(TS3)及四期(TS4)睡眠、快速眼动睡眠时间(REM)、觉醒期时间(WASO)、睡眠潜伏期时间(SL)均显著改善,且研究组以上指标改善均显著优于对照组(P<0.05)。两组日间功能障碍、睡眠质量、睡眠时间、睡眠障碍及入睡时间均显著改善,且研究组日间功能障碍、睡眠质量、睡眠时间、睡眠障碍及入睡时间显著优于对照组(P<0.05)。结论自拟平衡针灸通过调控PI3K-AKT信号通路及血清GABA水平,有效降低局部炎性反应,优化神经系统的递质传递,有效改善患者的治疗效果。

GABAergic网络在神经发育和脑疾病中对髓鞘再生的研究进展

少突胶质细胞前体细胞(oligodendrocyte precursor cells,OPCs)分化为成熟的少突胶质细胞(oligodendrocytes,OLs)是中枢神经系统轴突髓鞘形成和脱髓鞘疾病髓鞘再生的关键事件。研究表明,神经递质γ-氨基丁酸(γ-aminobutyric acid,GABA)、GABAergic突触及其网络调控对少突神经胶质细胞的增殖、分化、迁移及髓鞘形成具有重要的调节作用。因此,该文总结了近些年关于GABA及其受体在少突胶质细胞谱系中发挥的生物学功能,GABAergic中间神经元与OPCs之间的交互作用及其介导髓鞘形成的网络调控和未来潜在的候选药物的研究。基于此了解控制OLs分化机制对于确定促进髓鞘修复的治疗策略至关重要,围绕GABAergic的研究可能对开发脱髓鞘疾病的新型修复疗法具有潜在意义。

GABA和BABA诱导辣椒幼苗及果实对炭疽病抗性的生理影响

[目的]研究γ-氨基丁酸(GABA)和β-氨基丁酸(BABA)诱导辣椒幼苗和果实对炭疽病抗性的生理作用。[方法]以辣椒品种‘红冠3号’和‘川腾10号’为试材,采用50 mmol/L GABA和50 mmol/L BABA预处理1/2 MS固体培养基培养的辣椒幼苗和离体果实,并以不添加GABA和BABA为无预处理对照(CK),分析喷雾和针刺法接种炭疽菌(Colletotrichum socvillei)及无菌水(对照)后辣椒幼苗和果实的生理变化。[结果]接种炭疽菌0~8 d,2个辣椒品种幼苗叶片叶绿素a、b均呈下降趋势,在8 d时较对照(无菌水)差异均达显著水平(P<0.05,下同);根系生长速率也持续下降;而GABA和BABA各预处理组的叶绿素含量和根长比无预处理组下降趋势均明显减缓,GABA预处理叶绿素含量均高于其它处理组,在2 d时达显著水平;GABA和BABA各预处理组幼苗抗氧化酶活性均高于无预处理组0 d时,预处理组CAT和SOD活性已在0 d时达到无预处理组接菌8 d时活性水平,MDA含量无明显变化。接种8 d时,GABA预处理幼苗组内接菌8 d的SOD活性显著高于0 d对照,BABA预处理幼苗组内接菌8 d的SOD和POD均显著高于0 d对照;辣椒红果预处理组的抗氧化酶活性均高于无预处理组0 d时活性,预处理组内接菌8 d的CAT和POD活性高于对照0 d,MDA含量无明显变化,且预处理较无预处理接菌8 d红果病斑直径显著降低,分别降低1.34和0.68倍。此外,GABA、BABA预处理果实各对组内的对照0 d和接种8 d及组间的抗氧化酶活性变化和MDA活性变化与幼苗预处理试验结果变化趋势一致。[结论]GABA和BABA预处理提高了接种炭疽菌后辣椒幼苗的叶片叶绿素含量和根系生长速率。GABA和BABA预处理缓解了炭疽菌对辣椒红果的侵染。同时,GABA和BABA通过提高辣椒幼苗和果实抗氧化酶活性,降低MDA的积累,从而提高辣椒幼苗和果实对炭疽病的抗病性。

化痰祛瘀汤对脑小血管病大鼠认知功能及脑组织GABA、VILIP-1表达的影响

目的观察化痰祛瘀汤对脑小血管病大鼠认知功能及脑组织γ-氨基丁酸(GABA)和视锥蛋白样蛋白1(VILIP-1)表达的影响,探讨其治疗脑小血管病的作用机制。方法48只雄性SD大鼠随机分为空白组、模型组、中药低剂量组和中药高剂量组,每组12只。除空白组外,采用同种系微栓子体外注入法制备脑小血管病大鼠模型,中药低、高剂量组分别予化痰祛瘀汤1.25、2.5 g/kg灌胃,空白组及模型组灌胃等量蒸馏水,连续28 d。给药1、7、14、28 d行Morris水迷宫实验评估大鼠学习记忆能力,HE染色观察海马组织病理变化,免疫组化染色检测脑组织GABA、VILIP-1蛋白表达。结果与空白组比较,模型组大鼠Morris水迷宫实验逃避潜伏期明显延长(P<0.05),穿越平台次数明显减少(P<0.05),海马组织细胞排列杂乱、间隙增宽,细胞核萎缩、坏死,脑组织GABA表达明显降低(P<0.05),VILIP-1表达明显升高(P<0.05);与模型组比较,中药低、高剂量组大鼠给药7、14、28 d逃避潜伏期明显缩短(P<0.05),穿越平台次数明显增多(P<0.05),脑组织GABA表达明显升高(P<0.05),VILIP-1表达明显降低(P<0.05);与中药低剂量组比较,中药高剂量组大鼠各时点逃避潜伏期缩短,穿越平台次数增加,海马组织病理损伤减轻,脑组织GABA表达升高,VILIP-1表达降低,差异均有统计学意义(P<0.05)。结论化痰祛瘀汤可提高海马组织GABA表达、抑制VILIP-1表达,从而改善脑小血管病大鼠认知功能。

外源GABA对“脆红李”果实采后品质及抗氧化活性的影响

【目的】探究外源γ-氨基丁酸(GABA)处理对脆红李采后果实品质和抗氧化能力的影响。【方法】以‘脆红李’为材料,分别用0、0.1、0.5和1.0 mmol/L GABA溶液浸果,晾干后置于室温(28±1)℃贮藏6 d。在贮藏期(0~6 d)每天测定贮藏期间脆红李硬度、失重率、可溶性糖含量及过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性和丙二醛(MDA)含量。【结果】外源GABA处理能有效降低果实失重率,保持可溶性糖和硬度处于较高水平,同时,显著提高了CAT、SOD、POD活性及延迟了MDA含量的增加,贮藏效果为1.0 mmol/L>0.5 mmol/L>0.1 mmol/L>0 mmol/L。【结论】GABA通过维持果实硬度、可溶性糖含量和增强抗氧化活性以维持‘脆红李’果实采后贮藏品质。其中,1.0 mmol/LGABA处理对采后脆红李果实品质的保持效果较好,应用前景广阔。

基于四氢孕酮介导大鼠杏仁核和海马脑区GABA AR亚基的经前烦躁障碍症肝气逆证发病机制研究

目的观察外源性四氢孕酮(allopregnanolone,ALLO)及其抑制剂非那雄胺对经前烦躁障碍症(premenstrual dysphoric disorder,PMDD)肝气逆证模型大鼠接受期(R)和非接受期(NR)的行为学影响与GABA ARα4、GABA ARδmRNA和蛋白表达的影响,以探讨其发病机制。方法制备PMDD肝气逆证大鼠模型,将大鼠分为正常组R与NR(Control-R、Control-NR)、模型组R与NR(Model-R、Model-NR)、正常组R+ALLO与NR+ALLO(Control+A-R、Control+A-NR)、模型组R+ALLO与NR+ALLO(Model+A-R、Model+A-NR)、模型组R+非那雄胺与NR+非那雄胺(Model+F-R、Model+F-NR);运用高架十字迷宫实验和社会交互实验检测大鼠的行为学;荧光定量PCR和免疫荧光检测杏仁核和海马GABA ARα4和GABA ARδmRNA和蛋白表达。结果在行为学评价中,在NR期,在高架十字迷宫实验和在社会交互实验,模型组大鼠有焦虑行为产生以及社交能力下降(P<0.05),Model+A组能有效缓解焦虑症状和改善大鼠社会交往能力(P<0.05),Model+F组大鼠焦虑行为加重和社交障碍加重(P<0.05);荧光定量PCR和免疫荧光实验中,模型组GABA ARα4亚基在海马表达均上调(P<0.01),GABA ARδ亚基的表达均下调(P<0.01);Model+A组GABA ARα4亚基在杏仁核和海马表达降低(P<0.01),GABA ARδ亚基的表达海马脑区均升高(P<0.01)。结论ALLO可能通过介导GABA ARα4和GABA ARδ亚基的表达异常,改善PMDD的焦虑症状和社会交往能力,是PMDD肝气逆证的发病机制,为后续挖掘深层次PMDD肝气逆证的发病机制提供了依据和支撑。

抗GABABR脑炎四例

目的抗γ氨基丁酸B型受体(GABABR)脑炎四例,以减少临床误诊误治。方法收集4例曾初诊为其他疾病的抗GABABR脑炎的临床资料,并分析其临床特征及误诊原因。结果4例患者均有癫痫发作及认知障碍,2例(例2、例4)伴发精神症状。4例颅脑MRI均发现单侧或双侧颞叶病变。初步诊断分别为胶质瘤3例和短暂性脑缺血发作1例(例4)。误诊时间为12~68d。结论抗GABABR脑炎的临床特征与其他疾病存在交叉,提高对该疾病的认识、尽早完善特异性抗体检查是明确诊断的关键,从而减少临床误诊误治。

Selective leaching of lithium from spent lithium-ion batteries using sulfuric acid and oxalic acid

Traditional hydrometallurgical methods for recovering spent lithium-ion batteries(LIBs)involve acid leaching to simultaneously extract all valuable metals into the leachate.These methods usually are followed by a series of separation steps such as precipitation,extraction,and stripping to separate the individual valuable metals.In this study,we present a process for selectively leaching lithium through the synergistic effect of sulfuric and oxalic acids.Under optimal leaching conditions(leaching time of 1.5 h,leaching temperature of 70°C,liquid-solid ratio of 4 mL/g,oxalic acid ratio of 1.3,and sulfuric acid ratio of 1.3),the lithium leaching efficiency reached89.6%,and the leaching efficiencies of Ni,Co,and Mn were 12.8%,6.5%,and 21.7%.X-ray diffraction(XRD)and inductively coupled plasma optical emission spectrometer(ICP-OES)analyses showed that most of the Ni,Co,and Mn in the raw material remained as solid residue oxides and oxalates.This study offers a new approach to enriching the relevant theory for selectively recovering lithium from spent LIBs.

Recovery of Li, Ni, Co and Mn from spent lithium-ion batteries assisted by organic acids: Process optimization and leaching mechanism

The proper recycling of spent lithium-ion batteries(LIBs)can promote the recovery and utilization of valuable resources,while also negative environmental effects resulting from the presence of toxic and hazardous substances.In this study,a new environmentally friendly hydro-metallurgical process was proposed for leaching lithium(Li),nickel(Ni),cobalt(Co),and manganese(Mn)from spent LIBs using sulfuric acid with citric acid as a reductant.The effects of the concentration of sulfuric acid,the leaching temperature,the leaching time,the solid-liquid ratio,and the reducing agent dosage on the leaching behavior of the above elements were investigated.Key parameters were optimized using response surface methodology(RSM)to maximize the recovery of metals from spent LIBs.The maxim-um recovery efficiencies of Li,Ni,Co,and Mn can reach 99.08%,98.76%,98.33%,and 97.63%.under the optimized conditions(the sulfuric acid concentration was 1.16 mol/L,the citric acid dosage was 15wt%,the solid-liquid ratio was 40 g/L,and the temperature was 83℃ for 120 min),respectively.It was found that in the collaborative leaching process of sulfuric acid and citric acid,the citric acid initially provided strong reducing CO_(2)^(-),and the transition metal ions in the high state underwent a reduction reaction to produce transition metal ions in the low state.Additionally,citric acid can also act as a proton donor and chelate with lower-priced transition metal ions,thus speeding up the dissolution process.

Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO_(2) into carboxylic acids

The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.

Endogenous biosynthesis of docosahexaenoic acid(DHA)regulates fish oocyte maturation by promoting pregnenolone production

Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related to this phenomenon remains largely unknown.In this study,we employed two zebrafish genetic models,i.e.,elovl2^(-/-)mutant as an endogenous DHAdeficient model and fat1(omega-3 desaturase encoding gene)transgenic zebrafish as an endogenous DHA-rich model,to investigate the effects of DHA on oocyte maturation and quality.Results show that the elovl2^(-/-)mutants had much lower fecundity and poorer oocyte quality than the wild-type controls,while the fat1 zebrafish had higher fecundity and better oocyte quality than wildtype controls.DHA deficiency in elovl2^(-/-)embryos led to defects in egg activation,poor microtubule stability,and reduced pregnenolone levels.Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1,which encodes the cholesterol side-chain cleavage enzyme,thereby stabilizing microtubule assembly during oogenesis.In turn,the hypothalamic-pituitary-gonadal axis was enhanced by DHA.In conclusion,using two unique genetic models,our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.

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.

γ-氨基丁酸(GABA)的研究进展

γ-氨基丁酸(GABA)是一种广泛分布于动、植物和微生物体内的非蛋白氨基酸,于2009年被我国卫健委批准为“新资源食品”,在食品、医药、饲料等领域具有十分广阔的应用前景,近年来有关GABA的研究也逐渐成为热点。本文阐述了GABA的生物合成与代谢途径,归纳了GABA的化学合成、植物富集方法及目前常用的GABA检测技术,并对比分析其优缺点。此外,本文对GABA的主要生理功能及其作用机制进行总结,并对GABA的未来研究和发展趋势进行展望,以期为今后GABA的研究与应用提供参考。

Abiotic stress treatment reveals expansin like A gene OfEXLA1 improving salt and drought tolerance of Osmanthus fragrans by responding to abscisic acid

Sweet osmanthus(Osmanthus fragrans) is a having general approval aromatic tree in China that is widely applied to landscaping and gardening. However, the evergreen tree adaptability is limited by many environmental stresses. Currently, limited information is available regarding the genetic analysis and functional identification of expansin genes in response to abiotic stress in sweet osmanthus. In this study, a total of 29 expansin genes were identified and divided into four groups by genome-wide analysis from the sweet osmanthus genome. Transcriptome and quantitative Real-time PCR analysis showed that the cell wall-localized protein expansin-like A(OfEXLA1) gene was significantly induced by salt and drought treatment. Histochemical GUS staining of transgenic Arabidopsis lines in which GUS activity was driven with the OfEXLA1 promoter, GUS activity was significantly induced by salt, drought, and exogenous abscisic acid(ABA). In yeast, we found OfEXLA1overexpression significantly improved the population of cells compared with wild-type strains after NaCl and polyethylene glycol(PEG)treatment. Additionally, OfEXLA1 overexpression not only promoted plant growth, but also improved the salt and drought tolerance in Arabidopsis. To gain insight into the role of ABA signaling in the regulation of OfEXLA1 improving abiotic tolerance in sweet osmanthus, four differentially expressed ABA Insensitive 5(ABI5)-like genes(OfABL4, OfABL5, OfABL7, and OfABL8) were identified from transcriptome, and dualluciferase(dual-LUC) and yeast one hybrid(Y1H) assay showed that OfABL4 and OfABL5 might bind to OfEXLA1 promoter to accumulate the OfEXLA1 expression by responding to ABA signaling to improve abiotic tolerance in sweet osmanthus. These results provide the information for understanding the molecular functions of expansin-like A gene and molecular breeding of sweet osmanthus in future.

Dietary supplementation of benzoic acid and essential oils combination enhances intestinal resilience against LPS stimulation in weaned piglets

Background The benefits of combining benzoic acid and essential oils(BAO)to mitigate intestinal impairment during the weaning process have been well established,while the detailed underlying mechanism has not been fully elucidated.Previous research has primarily focused on the reparative effects of BAO on intestinal injury,while neglecting its potential in enhancing intestinal stress resistance.Methods In this study,we investigated the pre-protective effect of BAO against LPS-induced stress using a modified experimental procedure.Piglets were pre-supplemented with BAO for 14 d,followed by a challenge with LPS or saline to collect blood and intestinal samples.Results Our findings demonstrated that BAO supplementation led to significant improvements in piglets’final weight,average daily gain,and feed intake/body gain ratio.Additionally,BAO supplementation positively influenced the composition of intestinal microbiota,increasing beneficial Actinobacteriota and Alloprevotella while reducing harmful Desulfobacterota,Prevotella and Oscillospira.Furthermore,BAO supplementation effectively mitigated oxidative disturbances and inflammatory responses induced by acute LPS challenge.This was evidenced by elevated levels of T-AOC,SOD,and GSH,as well as decreased levels of MDA,TNF-α,and IL-6 in the plasma.Moreover,piglets subjected to LPS challenge and pre-supplemented with BAO exhibited significant improvements in intestinal morphological structure and enhanced integrity,as indicated by restored expression levels of Occludin and Claudin-1 compared to the non-supplemented counterparts.Further analysis revealed that BAO supplementation enhanced the jejunal antioxidative capacity by increasing GSH-Px levels and decreasing MDA levels under the LPS challenge and stimulated the activation of the Nrf2 signaling pathway.Additionally,the reduction of TLR4/NF-κB/MAPK signaling pathways activation and proinflammatory factor were also observed in the jejunal of those piglets fed with BAO.Conclusions In summary,our study demonstrates that pre-supplementation of BAO enhances the anti-stress capacity of weaned piglets by improving intestinal microbiota composition,reinforcing the intestinal barrier,and enhancing antioxidative and anti-inflammatory capabilities.These effects are closely associated with the activation of Nrf2 and TLR4/NF-κB/MAPK signaling pathways.

Bile acids,gut microbiota,and therapeutic insights in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver malignancy.The interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and progression.Under normal conditions,BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and BAs.The gut microbiota plays a critical role in BA metabolism,and BAs are endogenous signaling molecules that help maintain liver and intestinal homeostasis.Of note,dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis,thereby leading to liver inflammation and fibrosis,and ultimately contributing to HCC development.Therefore,understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying hepatocarcinogenesis.In this review,we comprehensively explore the roles and functions of BA metabolism,with a focus on the interactions between BAs and gut microorganisms in HCC.Additionally,therapeutic strategies targeting BA metabolism and the gut microbiota are discussed,including the use of BA agonists/antagonists,probiotic/prebiotic and dietary interventions,fecal microbiota transplantation,and engineered bacteria.In summary,understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.

Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting a-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

Shikimic acid accelerates phase change and flowering in Chinese jujube

The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties.

Gut microbiota induced abnormal amino acids and their correlation with diabetic retinopathy

AIM:To explore the correlation of gut microbiota and the metabolites with the progression of diabetic retinopathy(DR)and provide a novel strategy to elucidate the pathological mechanism of DR.METHODS:The fecal samples from 32 type 2 diabetes patients with proliferative retinopathy(PDR),23 with nonproliferative retinopathy(NPDR),27 without retinopathy(DM),and 29 from the sex-,age-and BMI-matched healthy controls(29 HC)were analyzed by 16S rDNA gene sequencing.Sixty fecal samples from PDR,DM,and HC groups were assayed by untargeted metabolomics.Fecal metabolites were measured using liquid chromatographymass spectrometry(LC-MS)analysis.Associations between gut microbiota and fecal metabolites were analyzed.RESULTS:A cluster of 2 microbiome and 12 metabolites accompanied with the severity of DR,and the close correlation of the disease progression with PDR-related microbiome and metabolites were found.To be specific,the structure of gut microbiota differed in four groups.Diversity and richness of gut microbiota were significantly lower in PDR and NPDR groups,than those in DM and HC groups.A cluster of microbiome enriched in PDR group,including Pseudomonas,Ruminococcaceae-UCG-002,Ruminococcaceae-UCG-005,Christensenellaceae-R-7,was observed.Functional analysis showed that the glucose and nicotinate degradations were significantly higher in PDR group than those in HC group.Arginine,serine,ornithine,and arachidonic acid were significantly enriched in PDR group,while proline was enriched in HC group.Functional analysis illustrated that arginine biosynthesis,lysine degradation,histidine catabolism,central carbon catabolism in cancer,D-arginine and D-ornithine catabolism were elevated in PDR group.Correlation analysis revealed that Ruminococcaceae-UCG-002 and Christensenellaceae-R-7 were positively associated with L-arginine,ornithine levels in fecal samples.CONCLUSION:This study elaborates the different microbiota structure in the gut from four groups.The relative abundance of Ruminococcaceae-UCG-002 and Parabacteroides are associated with the severity of DR.Amino acid and fatty acid catabolism is especially disordered in PDR group.This may help provide a novel diagnostic parameter for DR,especially PDR.