用三线摆检测鸡蛋的生熟度

自制三线摆,检测了鸡蛋的生熟程度.生鸡蛋摆动时周期迅速衰减,统计鸡蛋能够稳定摆动的周期可以敏感地判断鸡蛋的生熟程度.周期衰减来源于蛋清、蛋黄等液体之间及其与蛋壳之间的摩擦力引起的阻力矩.     

以蛋黄为对象对细胞增殖过程中卟啉代谢规律的研究

在以鸡胚胎为细胞繁殖模型,对细胞增殖过程中卟啉代谢规律的研究中,为了寻求能够更好的反映原卟啉Ⅸ(PpⅨ)代谢水平的监测对象,采用405 nm的激发波长,分别对鸡胚胎发育进程中的种蛋中的蛋黄、蛋清和尿囊液的荧光光谱进行测量分析。结果表明,和蛋清相比,蛋黄中PpⅨ 的荧光峰相对背景更为明显,在整个鸡胚发育过程中存在的时间也较长,是一种更为理想的对鸡胚胎发育进程中卟啉代谢规律进行研究的监测对象;同时发现在胚胎发育的初级阶段,蛋黄中PpⅨ的代谢水平随着发育的进程而逐渐升高,在第10天左右达到最大值,在发育后期代谢水平又逐渐降低。鸡胚胎发育进程中PpⅨ的这一代谢规律与其在恶性肿瘤发展过程中的代谢规律极为相似,进一步支持了卟啉代谢异常与细胞无限的迅速增殖相关的观点。     

中国文物彩绘常用胶料的显微共聚焦拉曼光谱特征研究

为了鉴定文物彩绘中常用胶料的种类,文章采用显微共聚焦拉曼光谱技术分析了猪皮胶、猪骨胶、蛋清、蛋黄、桃胶等中国古代文物彩绘常用胶料.通过对五种标准胶料的拉曼光谱分析,发现蛋白类胶料和桃胶的拉曼光谱存在明显差别,桃胶在1 463及1 088 cm-1 处存在两个糖类化合物的特征振动峰.虽然蛋白类胶料间的拉曼光谱具有一定的相...     

基于高光谱技术的有机鸡蛋与普通鸡蛋鉴别

当今全球范围内有机食品行业发展迅速,体现出消费者对食品质量安全的重视。相比于普通鸡蛋,有机鸡蛋因严格的生产条件以及更高的营养价值生产成本更高、售价更贵。市面上所销售的有机鸡蛋虽取得了严格有机食品认证标识,但依旧不能阻止不法份子将普通鸡蛋冒充有机鸡蛋销售,从而谋取利润。这一行为不仅会损害有机鸡蛋生产商的利益,也降低了人们对有机食品的信任度,为此需要一种有效的对有机鸡蛋和普通鸡蛋无损鉴别方法。使用高光谱技术透射成像的方式,可以获取物质内部的信息,以有机鸡蛋和普通鸡蛋为试验对象,采集鸡蛋样本364～1 025 nm波长范围的高光谱图像数据,从采集到的数据中提取出鸡蛋蛋清和蛋黄感兴趣区域(ROI)的平均透射光谱数据。根据透射光谱曲线图筛选出有机鸡蛋与普通鸡蛋光谱响应差异明显的波段区间,分别通过偏最小二乘判别分析(PLS-DA)和支持向量机(SVM)建立鸡蛋类别的鉴别模型,结果表明模型分别根据蛋黄区域与蛋清区域数据进行建模的鉴别准确率相近,进一步对蛋黄区域数据进行分析。由于高光谱数据量大且存在大量冗余信息,给数据采集、存储、传输和建模处理都带来不便,因此分别通过连续投影算法(SPA)和竞争性自适应重加权算法(CARS)对蛋黄ROI数据进行降维处理,剔除了大量冗余信息后再建模。最终,使用对蛋黄ROI区域运用SPA降维后得到的23个特征波长建立的SPA-SVM鉴别模型在测试集的准确率最高达到94.2%。结果表明,通过高光谱技术对有机鸡蛋和普通鸡蛋进行无损鉴别有一定效果。     

二维红外相关光谱研究温度对卵转铁蛋白构象的影响

采用傅里叶变换红外光谱(FTIR)和二维相关光谱分析技术研究了无铁卵转铁蛋白和饱和铁卵转铁蛋白在加热条件下(25～95 ℃)构象变化规律。结果表明,随着温度升高,无铁卵转铁蛋白在3 300 cm-1处的峰的迁移程度比饱和铁卵转铁蛋白大,说明卵转铁蛋白结合铁后氢键作用增强,对热的抵抗性增强。二维红外图谱分析显示,无铁卵转铁蛋白与饱和铁卵转铁蛋白的二级结构变化顺序为β-折叠>酰胺Ⅱ>-CH₂-弯曲振动。通过对比无铁卵转铁蛋白和饱和铁卵转铁蛋白的二维同步和异步图谱发现,在1 652和1 688 cm-1处的交叉峰存在差异,卵转铁蛋白结合铁后温度对其二级结构中α-螺旋影响变小,而对β-转角的影响变大。     

激光诱导击穿光谱结合偏最小二乘法直接检测皮蛋壳中的Cu含量

运用激光诱导击穿光谱(LIBS)技术对皮蛋壳中Cu元素直接进行检测,获得样本中Cu元素的特征谱线信息,采用湿法消解结合原子吸收分光光度计(AAS)测量样品中Cu元素的真实含量。由于LIBS检测的精度和准确度受到样品基体复杂,环境噪声,系统噪声,激光能量稳定性等一系列因素的影响,采用传统的单变量赛伯-罗马金拟合方式对样品的LIBS相对强度和浓度进行线性拟合不能满足定性分析的要求,因此,采用一种多变量的分析-偏最小二乘(PLS)对LIBS光谱数据进行了处理,比较分析了不同点数平滑处理和五种预处理方法对PLS建模精度和准确度的影响。分析得出采用11点平滑结合多元散射校正(MSC)预处理能有效地提高PLS建立的模型的相关系数,降低均方根误差和平均相对误差,有效提高了模型的准确性。研究结果表明,激光诱导击穿光谱技术能够准确地直接检测皮蛋壳中重金属Cu的含量,下一步的工作将对皮蛋进行批量试验,寻找出蛋壳与蛋清、蛋黄中重金属Cu的数量关系,实现通过LIBS检测皮蛋壳便可知蛋清、蛋黄中重金属含量的目标,为农产品质量安全提供新的快速无损检测技术方法。     

蛋类蛋白质的二级结构红外光谱研究

选取鸡、鸭、鹅、鹌鹑四种蛋类,对每种蛋的蛋清、蛋黄中的蛋白质分别在常态下及用重铬酸铵变性后进行红外表征。通过对比分析发现各谱图间存在微小差别。运用Omnic软件对得到的谱图进行处理,得到二阶导数光谱图。选择1 700~1 600和1 330~1 220cm-1两个波段的特征峰透过率作为数据分析基础,分析蛋类蛋白质的二级结构。结果表明红外光谱分析技术在蛋类蛋白质分析上有一定应用价值。     

热处理对蛋清卵类粘蛋白过敏原性及构象的影响

采用酶联免疫吸附法(ELISA)、圆二色谱(CD)、ANS荧光探针和紫外光谱(UV)系统研究了热处理对蛋清卵类粘蛋白过敏原性及构象的影响。结果显示,加热处理卵类粘蛋白的过敏原性降低,且随加热温度升高和加热时间延长,不断降低。经不同温度热处理后的卵类粘蛋白二级结构的α-螺旋,β-折叠,β-转角和无规卷曲之间相互转化,分子有序性降低;卵类粘蛋白的表面疏水性随加热温度的升高而降低;随加热的温度的升高,具有紫外吸收的氨基酸残基逐渐暴露,最大吸光度逐渐增大。由此可以推断,卵类粘蛋白的构象改变导致其过敏原性变化。     

静态计算光谱成像仪图谱反演的关键数据处理技术

静态计算光谱成像技术中图谱反演环节是实现其理论优势极为关键的一步, 是决定最终获得图谱质量优劣的数据处理技术. 本文为此专注于计算光谱的图谱反演环节,对图像压缩感知理论算法、图像重构算法、 以及针对图谱三维数据的反演算法都开展了深入的研究和比较, 并结合所研制系统的图谱数据传输全链路和工程研制过程中误差等因素进行全面详尽的仿真验证, 给出各种图谱反演算法验证、分析结果. 指出静态计算光谱成像系统研制中图谱反演环节的关键数据处理问题,适合采用的算法及其优化路线. 为顺利研制静态计算光谱成像仪,保证其理论优势的实现,提供了详实的分析、参考依据. 关键词： 计算光谱 编码孔径 压缩感知 图谱反演     

青海不同地区藏药渣驯的FTIR

建立渣驯的红外指纹图谱从而对渣驯进行鉴定、分析.应用红外光谱技术,对不同产地的渣驯进行测定.不同产地渣驯样品的FTIR不一致.首次建立了渣驯的红外指纹图谱,应用红外光谱技术可以达到无损、快速的鉴别渣驯药材.     

荧光法研究司帕沙星与白蛋白的作用

本文用荧光光谱法、分光光度法研究了水溶液中喹诺酮类药物司帕沙星与牛血清白蛋白 (BSA)、鸡蛋白 (CEA)的相互作用 ,求得它们间的结合常数为K鸡 =8 2 9× 10 6,K牛 =4 41× 10 7;结合位点数分别为n鸡=0 5 88,n牛 =0 793,并根据F rster非辐射能量转移机制 ,测定了司帕沙星与两种血清白蛋白相互结合时其给体 受体间距离 (R鸡 =1 99nm ,R牛 =2 0 9nm)和能量转移效率 (E鸡 =0 76 6 ,E牛 =0 714)。实验表明 ,随着温度升高 ,BSA及CEA的猝灭曲线斜率降低 ,证实了司帕沙星与BSA和CEA的相互结合作用为单一的静态猝灭过程 ,其作用机制属能量转移机制。通过两种血清白蛋白与抗菌药物司帕沙星结合反应 ,探讨了药物司帕沙星在生物体内与蛋白质的相互作用的生物学效应及其作用机理。     

Fluorescence Study of Sinapic Acid Interaction with Bovine Serum Albumin and Egg Albumin

The mechanism of interaction of protein with compounds used for preparation of matrices for matrix-assisted laser desorption ionization–mass spectrometry (MALDI-MS) methods is unknown. This paper reports the investigation of this mechanism for sinapic acid and bovine serum albumin and egg albumin. To examine these interactions in water a fluorescence method was applied. Sinapic acid can exist in three different forms, depending on pH: undissociated and with one or two deprotonated groups. pK_as of these states are: 4.47 for the COOH group and 9.21 for the OH group [1]. Therefore the interactions were examined at pH: 2.0, 6.4, and 10.5. The results show that sinapic acid at pH 10.5, being a bivalent anion, does not form any complex with these two proteins. At pH 2.0, sinapic acid, being undissociated, interacts weakly with egg albumin. Sinapic acid does not interact with bovine serum albumin at this pH. At pH 6.4, sinapic acid interacts only with bovine serum albumin. Parameters of the sinapic acid and bovine serum albumin complex were calculated based on the theory of multiple equlibria: the total number of binding sites, N = 15; the binding constant, K = 600 M ^–1; and the Hill's coefficient, j = 0.97. These parameters indicate (but not definitively because a large saturation was not obtained) that this is a simple binding of sinapic acid to bovine serum albumin with the binding sites of the same type.     

FTIR‐ATR Study of pH Effects on Egg Albumin Secondary Structure

Abstract

The pH effects on the secondary structures of egg albumin were investigated using Fourier transform infrared–attenuated total reflection (FTIR‐ATR) technique with a single‐bounce diamond crystal. The albumin was first denatured in a series of solutions with pH ranging from 1 to 12. The albumin film was then cast on the ATR crystal from the albumin solution for the IR spectrum collection. Significant secondary structure spectral differences were observed for these films. The findings are presented in terms of the shape and position of the albumin amide I band between 1600 and 1700 cm^?1.     

Experimental analysis of the dynamic, mechanical behaviour of a chicken egg

The dynamic, mechanical behaviour of a chicken egg is assessed. Experimental modal analysis tests revealed several spherical modes in the 2- frequency band. An identification of the mode shapes, the resonant frequencies and corresponding damping ratios of these modes is obtained. The study allows the interpretation of the vibration response of an egg excited at its equator with a light mechanical impact which could open the door towards an automated egg inspection system.     

Novel magnetic supports for small molecule affinity capture of proteins for use in proteomics

Magnetic supports are tested for use in batch affinity capture of proteins. Two types of magnetic polymer composites were used for solid phase synthesis and for the batch affinity chromatography of folate binding protein from a protein mixture. Gly-Gly-L-Methotrexate as well as other analogs were synthesized on magnetic supports consisting of either polyoxyalkyleneamine grafted onto polystyrene beads or a copolymer of polyethylene glycol dimethylacrylamide (PEGA). Both supports incorporated within their matrix sub-micron particles of paramagnetic magnetite. The peptide-methotrexate analogs were attached to the magnetic supports via a photocleavable linker. The bound methotrexate-peptide analogs were equilibrated with a protein mixture consisting of bovine albumin, chicken albumin, folate binding protein, lysozyme, lactoferrin and lactoperoxidase precursor in phosphate buffered saline (PBS) and then after magnetically separating and washing the supports of any unbound components the bound protein was removed either through the photocleavage of the tethered methotrexate-peptide ligand or via exchange with soluble methotrexate. In all cases, the photocleavage or exchange with soluble methotrexate released folate binding protein as the major affinity captured protein. Of the two magnetic supports tested, the PEGA based support was found to be superior to the polyoxyalkyleneamine grafted polystyrene support and comparable to beaded agarose in releasing bound folate binding protein. Of the two methods for removing bound protein, photocleavage of the covalently attached ligand was found to release exclusively folate binding protein as opposed to exchange with soluble methotrexate which released residual amounts of the non-specifically bound proteins bovine and chicken albumin, in addition to folate binding protein. Thus, use of the PEGA based magnetic support in conjunction with a photocleavable linker should help facilitate the automation of multiple parallel affinity chromatography for proteomics applications.     

Molecular aggregation and property changes of egg yolk low-density lipoprotein induced by ethanol and high-density ultrasound

Solvent and physical treatment are widely used in egg yolk processing, but the detailed changes in the molecular structure of egg yolk proteins during processing are unclear. The aim of this study was to investigate the effects of ethanol and ultrasonic treatments on chicken egg yolk low-density lipoprotein (LDL). The solubility, emulsifying activity and emulsifying stability decreased by 74.75%, 46.91%, and 81.58% after ethanol treatment, respectively. The average particle size of ethanol-treated LDL increased 13.3-fold to 937.85 nm. These results suggested that ethanol treatment induced wide-ranging aggregation of LDL. In contrast to ethanol treatment, ultrasonic treatment promoted the solubility and emulsifying stability of LDL and enhanced its zeta-potential (119.56%) and surface hydrophobicity (10.81%). Based on particle size analysis and transmission electron microscopy, approximately 34.65% of LDL had undergone aggregation and the molecular interface became more flexible after ultrasonic treatment. These results revealed the detailed changes in egg yolk LDL structure and properties during solvent (ethanol) and physical (ultrasound) processing.     

Pulsed laser ablation of pepsin on an inorganic substrate

Pressed pepsin pellets used as targets were ablated with the pulses of the Nd-YAG laser. The activity of the pepsin thin layer, deposited on a glass substrate, was successfully detected by analyzing the proteolytic degradation areas on the polyacrylamide gel (PA-gel) copolymerized with albumin from the hen egg white (ovalbumin), used as an enzymatic substrate.     

Distribution of merocyanine 540 in phospholipid membranes

The interaction of the fluorescent photosensitizer merocyanine 540 (MC-540) with model phospholipid membranes was studied. Two different-colored species (monomers and dimers) of MC-540 were registered in phospholipid liposomes. Variations in both phospholipid composition (DMPC, DPPC, POPC, egg PC) and temperature (15–60°C) resulted in changes in the MC-540 monomerdimer distribution. The values of the monomer-dimer equilibrium constant of MC-540 in egg PC (K=14.8 M), in POPC (K=26.7 M), and in DMPC (K=271.0 M) were determined at the temperature of 23±2°C. Suppression of MC-540 association with phospholipid bilayers was provoked by the addition of albumin to a liposome suspension. Albumin was observed to compete very successfully with lecithins containing saturated fatty acid chains (DPPC, DMPC), while only a weak competition of albumin with unsaturated lecithins (POPC, egg PC) for binding MC-540 molecules was registered.     

Investigation of biological systems by high resolution 2 mm wave band ESR

The application of the high resolution ESR technique for investigation of various biological systems is shown. The advantages of the technique in the study of structural, conformational and dynamic characteristics are exemplified by spin labeled human serum albumin, egg lysozyme, liposome membranes, inverted micelles, α-chymotrypsin, cotton fiber and cellulose. The polarity of microenvironment and the mechanisms of molecular mobility of the objects under study are determined. The combination of high resolution and saturation transfer techniques is shown to give the detailed analysis of very slow molecular motions in biological objects. Peroxide radicals in biosystems are identified by the ESR spectra of the 2 mm wave band.     

RAYLEIGH LIGHT SCATTERING ENHANCING REACTION OF DIBROMOCHLOROARSENAZO AND PROTEINS SYSTEM AND ITS ANALYTICAL APPLICATION

Based on the enhancement effects of Rayleigh light scattering (RLS) on Arsenazo-DBC, a novel quantitative method for the determination of proteins in aqueous solutions has been proposed. The reaction of Dibromochloroarsenazo (Arsenazo-DBC) and five proteins (BSA, HSA, egg albumin, human γ-IgG, Lysozyme) has been studied. Under optimal conditions the dynamic ranges for proteins were 2.5–60.0 μg·ml^?1, and the detection limits for HSA and BSA were at 98.50 ng·ml^?1 and 88.10 ng·ml^?1, respectively. Comparing with other methods, the method is simple, practical and relatively free from interference from coexisting substances. The method was employed for the determination of total protein in human serum with satisfactory results.