Structural characterization

结构表征
  • 文章类型: Journal Article
    Arah1是花生过敏原中含量最高的卵白,被鉴定为花生过敏原的生物标志物。在这项研究中,将Arah1与咖啡酸(CA)共价复合,以研究共价缀合对Arah1的抗原性和蛋白质结构特性的影响。Arah1和CA共价复合后,与对照Arah1相比,Arah1的IgG结合能力降低。此外,Arah1的结构从有序变为无序,分子间氢键的数量减少,一些疏水基团被暴露或疏水肽被释放。CA中的羧基与Arah1中的氨基反应。Arah1-CA的消化率增加。体外消化30分钟后,无法检测到Arah1-CA的抗原性。这些发现可为进一步研究低变应原性花生产品提供参考。
    Ara h1 was the highest content of peanut allergen protein, identified as a biomarker of peanut allergen. In this study, Ara h1 was covalently complexed with caffeic acid (CA) to research the effects of covalent conjugation on the antigenicity and protein structural properties of Ara h1. After the covalent complexing of Ara h1 and CA, the IgG-binding capacity of Ara h1 was reduced compared with that of control Ara h1. Moreover, the structure of Ara h1 changed from ordered to disordered, the number of intermolecular hydrogen bonds decreased, and some hydrophobic groups were exposed or hydrophobic peptides were released. The carboxyl group in CA reacted with the amino group in Ara h1. The digestibility of Ara h1-CA was increased. The antigenicity of Ara h1-CA was undetectable after 30 min of digestion in vitro. These findings can serve as a reference for further research on hypoallergenic peanut products.
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  • 文章类型: Journal Article
    制备了白及新鲜块茎(BSPS)的均质多糖,并使用HP-GPC对其进行了广泛表征,比色法,FT-IR,甲基化,GC-MS,NMR,刚果红实验,SEM和AFM。BSPS的分子量为722.90kDa。BSPS由摩尔比为1:2.5的葡萄糖和甘露糖组成。BSPS的直链结构主要由→4)-β-d-Glcp-(1→和→4)-β-d-Manp-(1→残基。与→4的C2连接的O-乙酰基)-β-d-Manp-(1→残基。其单糖摩尔比,分子量,O-乙酰基取代的位置与以前报道的B.striata干块茎多糖的位置不同。此外,BSPS显着提高了生存能力(约10%,浓度为3.125-25μg/mL),分化(1.5-4倍),迁移(15%-70%),和C2C12细胞的侵袭(1.84-4.65倍)。值得注意的是,BSPS显著加速小鼠表皮再生和伤口愈合。本研究首次报道了纹状体新鲜块茎中多糖的结构。结果表明,BSPS可以作为一种新型的天然伤口愈合药物进行探索。
    A homogeneous polysaccharide from Bletilla striata fresh tuber (BSPS) was prepared and extensively characterized using HP-GPC, colorimetry, FT-IR, methylation, GC-MS, NMR, Congo red experiment, SEM and AFM. The molecular weight of BSPS was 722.90 kDa. BSPS consisted of glucose and mannose in the molar ratio of 1: 2.5. BSPS had a linear chain structure consisting mainly of →4)-β-d-Glcp-(1 → and →4)-β-d-Manp-(1 → residues. O-acetyl group linked to C2 of →4)-β-d-Manp-(1 → residue. Its monosaccharide molar ratio, molecular weight, and O-acetyl substituted position were different from that of the polysaccharide from B. striata dried tuber reported previously. Furthermore, BSPS significantly promoted the viability (ca. 10 % at concentrations of 3.125-25 μg/mL), differentiation (1.5-4 folds), migration (15 %-70 %), and invasion (1.84-4.65 folds) of C2C12 cells. Of note, BSPS remarkably accelerated the epidermal regeneration and wound healing in mice. This study for the first time reported the structure of polysaccharides in B. striata fresh tubers. The results demonstrated that BSPS could be explored as a novel natural wound-healing drug.
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  • 文章类型: Journal Article
    紫花苜蓿多糖(MSP)是从紫花苜蓿中提取的有益化合物,具有多种药用活性。然而,对它们的降血糖作用知之甚少。在这项研究中,MSP-II-a,Mw为4.3×104Da的中性多糖,从紫花苜蓿中分离和纯化。单糖组成分析确定MSP-II-a由阿拉伯糖组成,葡萄糖,半乳糖,甘露糖,鼠李糖,和木糖的摩尔比为2.1:4.0:1.1:0.4:1.4:1.1。MSP-II的结构表征使用甲基化分析的组合进行,傅里叶变换红外光谱,和扫描电子显微镜。结果表明,MSP-II-a主要由1,4-p-Glc组成,1,3,4-Rha,和1,3-p-Gal糖苷键,显示具有不规则叶片形状的网状纹理。体外实验表明,MSP-II-a,在200和400μg/mL的浓度下,促进胰岛素抵抗3T3-L1脂肪细胞的葡萄糖摄取。体内研究表明,MSP-II-a通过降低HFD/STZ诱导的糖尿病小鼠的空腹血糖水平和增加肝糖原合成,可显着减轻胰岛素抵抗。这些发现揭示了MSP-II-a是具有潜在降血糖活性的生物活性多糖的有希望的来源。
    Medicago sativa polysaccharides (MSPs) are beneficial compounds extracted from Medicago sativa L. that exhibit multiple medicinal activities. However, little is known about their hypoglycemic effects. In this study, MSP-II-a, a neutral polysaccharide with an Mw of 4.3 × 104 Da, was isolated and purified from M. sativa L. Monosaccharide composition analysis determined that MSP-II-a was composed of arabinose, glucose, galactose, mannose, rhamnose, and xylose in a molar ratio of 2.1:4.0:1.1:0.4:1.4:1.1. Structural characterization of MSP-II was performed using a combination of methylation analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results showed that MSP-II-a was mainly comprised of 1,4-p-Glc, 1,3,4-Rha, and 1,3-p-Gal glycosidic linkages, revealing a mesh-like texture with irregular blade shapes. In vitro assays demonstrated that MSP-II-a, at concentrations of 200 and 400 μg/mL, promoted glucose uptake in insulin-resistant 3T3-L1 adipocytes. In vivo studies have shown that MSP-II-a significantly alleviates insulin resistance by reducing fasting blood glucose levels and increasing hepatic glycogen synthesis in HFD/STZ-induced diabetic mice. These findings revealed that MSP-II-a is a promising source of bioactive polysaccharides with potential hypoglycemic activity.
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  • 文章类型: Journal Article
    溶液等离子体法(SPP)用于对金黄色葡萄球菌进行灭菌(S.金黄色葡萄球菌)在原料奶(RM)中。杀菌效果分析和动力学分析表明,细菌浓度和电极间距离与杀菌效果呈负相关,而放电电压为正。在4kV时取得了较好的杀菌效果。电化学指数分析表明,RM的pH值没有变化。DO含量下降。电导率随放电电压的增加而增加。营养素含量分析表明,酸度的含量,乳糖,脂肪,蛋白质减少。SPP处理后的RM显示出比对照更高的酸味值和略低的收敛性值。较高的放电电压和电极之间较窄的距离呈现较强的效果。使用激光粒度仪进行了CM和MFG的结构表征,FTIR,1HNMR,XRD,AFM。结果表明,CMs的主要化学结构基本不变。具有更窄的电极间距离和更低的放电电压的SPP在分子水平上显著降低了MFG的尺寸和聚集。在4kV/2mm时,CM和MFG的粒径从238nm和523nm减小到224nm和302nm,分别。MFG的平均直径从45nm减小到18nm。因此,SPP是牛奶工业中潜在的方法,为饮料的保存和加工提供了新思路。
    Solution plasma process (SPP) was used for sterilizing Staphylococcus aureus (S. aureus) in raw milk (RM). The sterilization efficacy analysis and kinetics analysis showed bacterial concentration and the distance between electrodes were negatively correlated with the sterilization effect, while discharge voltage was positive. The better sterilization effect was achieved at 4 kV. The electrochemical indices analysis indicated that pH value of RM had no changed. The DO content decreased. The conductivity increased with the increasing discharge voltage. The nutrient content analysis revealed that the content of acidity, lactose, fat, and protein decreased. RM after SPP treatment exhibited higher values of sourness and slightly lower values of astringency than the control. The higher discharge voltage and narrower distance between electrodes presented the stronger effect. The structural characterization of CMs and MFGs was carried out using a laser particle sizer, FTIR, 1H NMR, XRD, and AFM. The results showed that the main chemical structure of CMs was unchanged basically. The SPP with the narrower distance between electrodes and lower discharge voltage significantly reduced the size and aggregation of MFGs at the molecular level. At 4 kV/2 mm, the particle sizes of CMs and MFGs were reduced from 238 nm and 523 nm to 224 nm and 302 nm, respectively. The average diameter of MFGs was reduced from 45 nm to 18 nm. Therefore, SPP is a potential method in the milk industry and provides a new idea for the preservation and processing of beverage.
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  • 文章类型: Journal Article
    稀土掺杂CeO2材料在固体氧化物燃料电池和电解槽等高温能量转换装置中有着广泛的应用。然而,了解结构和电气特性之间的复杂关系,特别是关于稀土离子的大小和含量,仍然是一个正在进行辩论的主题,发表的结果相互矛盾。在这项研究中,我们对Ce1-xLnxO2-x/2样品(x≤0.6;Ln=La,Nd,Sm,Gd,和Yb)使用X射线和中子粉末衍射,拉曼光谱,和电子衍射。稀土掺杂剂含量的增加导致从无序萤石结构到C型有序上层结构的逐步相变,伴随着降低的离子电导率。由于较低的晶格单元畸变,具有低掺杂剂含量(x=0.2)的样品在Gd3+和Sm3+系列中表现出更高的离子电导率。相反,高掺杂样品(x=0.6)对较大的稀土掺杂剂阳离子表现出优异的电导率。热重分析证实,随着掺杂剂浓度的增加,吸水率和质子电导率增加,虽然电子电导率保持相对不受影响,导致离子运输数量减少。这些发现为稀土掺杂CeO2的传输特性与缺陷引起的局部畸变之间的关系提供了见解,表明开发具有混合离子氧化物的新型功能材料的潜力,质子,和高温能源系统的电子电导率。
    Rare-earth doped CeO2 materials find extensive application in high-temperature energy conversion devices such as solid oxide fuel cells and electrolyzers. However, understanding the complex relationship between structural and electrical properties, particularly concerning rare-earth ionic size and content, remains a subject of ongoing debate, with conflicting published results. In this study, we have conducted comprehensive long-range and local order structural characterization of Ce1-xLnxO2-x/2 samples (x ≤ 0.6; Ln = La, Nd, Sm, Gd, and Yb) using X-ray and neutron powder diffraction, Raman spectroscopy, and electron diffraction. The increase in the rare-earth dopant content leads to a progressive phase transformation from a disordered fluorite structure to a C-type ordered superstructure, accompanied by reduced ionic conductivity. Samples with low dopant content (x = 0.2) exhibit higher ionic conductivity in Gd3+ and Sm3+ series due to lower lattice cell distortion. Conversely, highly doped samples (x = 0.6) exhibit superior conductivity for larger rare-earth dopant cations. Thermogravimetric analysis confirms increased water uptake and proton conductivity with increasing dopant concentration, while the electronic conductivity remains relatively unaffected, resulting in reduced ionic transport numbers. These findings offer insights into the relationship between transport properties and defect-induced local distortions in rare-earth doped CeO2, suggesting the potential for developing new functional materials with mixed ionic oxide, proton, and electronic conductivity for high-temperature energy systems.
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  • 文章类型: Journal Article
    肽疗法市场在2023年被评估为约45.67BN,预计从2024年到2032年将以约5.63%的复合年增长率(80.4BN)大幅增长。在先锋肽的专利垄断到期后,到2032年,通用肽预计将达到271亿美元,和通用肽变得可访问。出于上述原因,通用制造商正在冒险进入基于肽的治疗剂。关于肽的表征,有大量的材料可获得,这对研究人员来说是相当混乱的。FDA认为,ANDA申请人现在可以证明,拟议的通用合成肽药物产品中的活性成分与先前已批准的rDNA来源的肽中的活性成分“相同”。为了确保疗效,安全,以及开发过程中肽疗法的质量,监管机构要求利用几种正交方法进行全面表征。本文通过根据从肽的鉴定到肽治疗剂的物理化学性质的关键质量属性分段成不同的片段来阐述肽表征,这将需要基于肽链的大小和肽的分子量来证明与参考产品的同一性。简要解释了关于每种单独技术和每种测试的正交技术的文章见解。还讨论了根据监管要求的通用肽中的杂质要求。
    The Peptide therapeutics market was evaluated to be around USD 45.67 BN in 2023 and is projected to witness massive growth at a CAGR of around 5.63 % from 2024 to 2032 (USD 80.4 BN). Generic peptides are expected to reach USD 27.1 billion by 2032 after the patent monopoly of the pioneer peptides expires, and generic peptides become accessible. The generic manufacturers are venturing into peptide-based therapeutics for the aforementioned reasons. There is an abundance of material accessible regarding the characterization of peptides, which can be quite confusing for researchers. The FDA believes that an ANDA applicant may now demonstrate that the active component in a proposed generic synthetic peptide drug product is the \"same\" as the active ingredient in a peptide of rDNA origin that has previously been approved. To ensure the efficacy, safety, and quality of peptide therapies during development, regulatory bodies demand comprehensive characterization utilizing several orthogonal methodologies. This article elaborates the peptide characterization by segmenting into different segments as per the critical quality attribute from identification of the peptide to the physicochemical property of the peptide therapeutics which will be required to demonstrate the sameness with reference product based on the size of the peptide chain and molecular weight of the peptides. Article insights briefly on each individual technique and the orthogonal techniques for each test were explained. The impurities requirements in the generic peptides as per the regulatory requirement were also discussed.
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  • 文章类型: Journal Article
    天然多糖具有广泛的生物活性,它们的结构特征密切相关,包括它们的分子量分布,尺寸,单糖组成,糖苷键类型和空间构象,等。尺寸排阻色谱(SEC)和不对称流场-流动分馏(AF4),作为两种有效的分离技术,两者都有持续发展和提高的潜力。该手稿回顾了SEC和AF4的基本原理和分离应用。多糖的结构信息和空间构象可以使用与多个检测器偶联的SEC或AF4获得。此外,本手稿详细阐述了通过SEC分离的多糖等样品的剪切降解。此外,还讨论了两种方法在应用过程中出现的异常洗脱。SEC和AF4都具有持续开发和完善的巨大潜力,从而为多糖分离和表征提供增加的可能性和机会。
    Natural polysaccharides exhibit a wide range of biological activities, which are closely related to their structural characteristics, including their molecular weight distribution, size, monosaccharide composition, glycosidic bond types and spatial conformation, etc. Size exclusion chromatography (SEC) and asymmetrical flow field-flow fractionation (AF4), as two potent separation techniques, both harbor potential for continuous development and enhancement. This manuscript reviewed the fundamental principles and separation applications of SEC and AF4. The structural information and spatial conformation of polysaccharides can be obtained using SEC or AF4 coupled with multiple detectors. In addition, this manuscript elaborates in detail on the shear degradation of samples such as polysaccharides separated by SEC. In addition, the abnormal elution that occurs during the application of the two methods is also discussed. Both SEC and AF4 possess considerable potential for ongoing development and refinement, thereby offering increased possibilities and opportunities for polysaccharide separation and characterization.
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  • 文章类型: Journal Article
    植物蛋白由于其低碳足迹而获得了动物蛋白的广泛关注,营养均衡,高可持续性。这些特性使植物蛋白纳米载体有望在药物输送中应用,营养食品,功能性食品,和其他领域。Zein,玉米淀粉加工的主要副产品,价格低廉且广泛可用。其独特的自组装特性导致其在各种食品和药物系统中的广泛使用。玉米醇溶蛋白的功能可调性允许装载和运输生物活性物质的优异性能。叶黄素提供多种生物活性功能,如抗氧化剂和视力保护,但化学稳定性差,生物利用度低。纳米嵌入技术可以构建各种负载玉米醇溶蛋白的叶黄素纳米递送系统来解决这些问题。这篇综述概述了玉米醇溶蛋白负载叶黄素纳米系统构建的最新进展。它讨论了这些系统的基本性质;系统地介绍了制备技术,结构表征,和功能特性;并分析和预测负载玉米醇溶蛋白的叶黄素纳米系统的目标控制释放和生物可及性。研究了玉米醇溶蛋白和叶黄素在纳米复合物中的相互作用和协同作用,以阐明玉米醇溶蛋白-叶黄素纳米颗粒的形成机理和构象关系。玉米醇溶蛋白的理化性质与分子结构密切相关。玉米醇溶蛋白及其改性产品可以通过各种方法包封和保护叶黄素,创造更稳定和有效的玉米醇溶蛋白负载叶黄素纳米系统。此外,在玉米醇溶蛋白及其衍生物中嵌入叶黄素可增强叶黄素的消化稳定性,溶解度,抗氧化性能,和整体生物利用度。
    Plant proteins have gained significant attention over animal proteins due to their low carbon footprint, balanced nutrition, and high sustainability. These attributes make plant protein nanocarriers promising for applications in drug delivery, nutraceuticals, functional foods, and other areas. Zein, a major by-product of corn starch processing, is inexpensive and widely available. Its unique self-assembly characteristics have led to its extensive use in various food and drug systems. Zein\'s functional tunability allows for excellent performance in loading and transporting bioactive substances. Lutein offers numerous bioactive functions, such as antioxidant and vision protection, but suffers from poor chemical stability and low bioavailability. Nano-embedding technology can construct various zein-loaded lutein nanodelivery systems to address these issues. This review provides an overview of recent advances in the construction of zein-loaded lutein nanosystems. It discusses the fundamental properties of these systems; systematically introduces preparation techniques, structural characterization, and functional properties; and analyzes and predicts the target-controlled release and bioaccessibility of zein-loaded lutein nanosystems. The interactions and synergistic effects between Zein and lutein in the nanocomplexes are examined to elucidate the formation mechanism and conformational relationship of zein-lutein nanoparticles. The physical and chemical properties of Zein are closely related to the molecular structure. Zein and its modified products can encapsulate and protect lutein through various methods, creating more stable and efficient zein-loaded lutein nanosystems. Additionally, embedding lutein in Zein and its derivatives enhances lutein\'s digestive stability, solubility, antioxidant properties, and overall bioavailability.
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  • 文章类型: Journal Article
    这项研究开发了一种对治疗缺铁性贫血至关重要的创新铁补充剂。采用微波辅助热水法从杜仲叶中提取多糖,随后,通过与FeCl3的共热合成合成多糖-铁配合物。物理化学性质,结构,使用FE-SEM分析了配合物的热稳定性,SEC-MALLS,FT-IR,XRD,和DSC技术。此外,通过体外实验评价多糖-铁复合物的抗氧化活性。结果表明,多糖-铁络合物的铁含量为6.1%,平均粒径为860.4nm。微观结构分析表明,多糖-铁复合物具有片状形貌,表面光滑致密。此外,Fe3+复合物的形成不会改变多糖的结构框架;相反,它增强了多糖的热稳定性。与传统的铁补充剂相比,杜氏酵母衍生的多糖-铁复合物表现出显著的抗氧化活性。因此,这种新型化合物显示出作为可行的铁补充剂的巨大潜力。
    An innovative iron supplement crucial for treating iron-deficiency anemia was developed in this study. Polysaccharide was extracted from Eucommia ulmoides leaves using a microwave-assisted hot water method, and subsequently, the polysaccharide-iron complex was synthesized through co-thermal synthesis with FeCl3. The physicochemical properties, structure, and thermal stability of the complex were analyzed using FE-SEM, SEC-MALLS, FT-IR, XRD, and DSC techniques. Furthermore, the antioxidant activity of the polysaccharide-iron complex was evaluated through an experiment in vitro. The results revealed that the polysaccharide-iron complex had an iron content of 6.1% and an average particle size of 860.4 nm. The microstructure analysis indicated that the polysaccharide-iron complex possessed a flaky morphology with smooth and compact surfaces. Moreover, the formation of the Fe3+ complex did not alter the structural framework of the polysaccharide; instead, it enhanced the polysaccharide\'s thermal stability. Compared to traditional iron supplements, the E. ulmoides-derived polysaccharide-iron complex demonstrated significant antioxidant activity. Therefore, this novel compound exhibits significant potential as a viable iron supplement.
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  • 文章类型: Journal Article
    绿豆生长过程中硒(Se)的生物强化是提高硒含量和品质的有效方法。然而,硒生物强化对绿豆蛋白理化性质的影响尚不清楚。这项研究的目的是澄清成分的变化,Se形式,颗粒结构,功能属性,热稳定性,在四个硒施用水平下绿豆蛋白的凝胶特性。结果表明,绿豆蛋白中硒含量呈剂量依赖性增加,在最高浓度下增加7.96倍(P1)和8.52倍(P2)。外源Se的应用促进了无机Se向有机Se的转化。其中,硒代蛋氨酸(SeMet)和甲基硒代半胱氨酸(MeSeCys)通过S代谢途径取代了Met和Cys,成为富硒绿豆蛋白中的主要有机Se形式,占总硒含量的80%以上。在SeMet和MeSeCys含量增加的情况下,30g/hm2的外源硒显着上调了蛋白质含量,并促进了含硫蛋白质成分和疏水性氨基酸的合成。同时,Cys和Met取代改变了巯基(SH),β-sheets,和蛋白质的β转角。粒径和微观结构特征取决于蛋白质本身,不受外源Se的影响。Se诱导的疏水性氨基酸和β-折叠的含量增加协同增加了蛋白质的热稳定性。适度施硒改变了绿豆蛋白的功能特性,主要体现在持油能力(OHC)和发泡能力(FC)的显著提高。此外,外源硒诱导的SH和β-折叠的增加可以改变蛋白质分子间网络,有助于增加储能模量(G\')和损耗模量(G”),这导致形成了更高弹性的凝胶。本研究进一步促进了绿豆蛋白在食品加工领域的应用,为富硒绿豆蛋白的广泛开发提供了理论依据。
    Selenium (Se) biofortification during the growth process of mung bean is an effective method to improve the Se content and quality. However, the effect of Se biofortification on the physicochemical properties of mung bean protein is unclear. The objective of this study was to clarify the changes in the composition, Se forms, particle structure, functional properties, thermal stability, and gel properties of mung bean protein at four Se application levels. The results showed that the Se content of mung bean protein increased in a dose-dependent manner, with 7.96-fold (P1) and 8.52-fold (P2) enhancement at the highest concentration. Exogenous Se application promotes the conversion of inorganic Se to organic Se. Among them, selenomethionine (SeMet) and methyl selenocysteine (MeSeCys) replaced Met and Cys through the S metabolic pathway and became the dominant organic Se forms in Se-enriched mung bean protein, accounting for more than 80 % of the total Se content. Exogenous Se at 30 g/hm2 significantly up-regulated protein content and promoted the synthesis of sulfur-containing protein components and hydrophobic amino acids in the presence of increased levels of SeMet and MeSeCys. Meanwhile, Cys and Met substitution altered the sulfhydryl groups (SH), β-sheets, and β-turns of protein. The particle size and microstructural characteristics depend on the protein itself and were not affected by exogenous Se. The Se-induced increase in the content of hydrophobic amino acids and β-sheets synergistically increases the thermal stability of the protein. Moderate Se application altered the functional properties of mung bean protein, which was mainly reflected in the significant increase in oil holding capacity (OHC) and foaming capacity (FC). In addition, the increase in SH and β-sheets induced by exogenous Se could alter the protein intermolecular network, contributing to the increase in storage modulus (G\') and loss modulus (G″), which resulted in the formation of more highly elastic gels. This study further promotes the application of mung bean protein in the field of food processing and provides a theoretical basis for the extensive development of Se-enriched mung bean protein.
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