用于放射性砹(碘)标记蛋白质的偶联剂SPC的合成及表征

以5-溴烟酸为起始物，通过3步主要反应合成了一种适用于蛋白质放射性砹(碘)标记的偶联剂——5-(三正丁基锡)-3-吡啶甲酸N-琥珀酰亚胺酯(SPC)，并用核磁共振(NMR)、质谱(MS)、高效液相色谱(HPLC)等进行了表征。以该试剂为双功能偶联剂，实现了IgG的^125I标记，标记率达30％以上。标记产物在体外具有较高的稳定性。     

Retailers' tagging practices: a potential liability?

This study investigates the coverage of federally mandated information on over‐the‐counter (OTC) drug labels by electronic article surveillance (EAS) tags applied to the exterior of cartons. Using adult‐strength analgesics containing acetaminophen as a case study, researchers investigated the issue in Houston, Texas (24 stores) and Lansing, Michigan (33 stores). The information obscured by EAS tags was identified and classified for a total of 849 packages using a standardized data collection instrument. The results indicated that 293 packages examined, or 34.5%, had information mandated by the US Food and Drug Administration (US FDA) fully or partially obscured by the EAS tags. Retailers and manufacturers should be aware of such practices to reduce potential liability. Recommendations for improving EAS tag usage on OTC products are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

Cysteine tagging for MS-based proteomics

Amino acid-tagging strategies are widespread in proteomics. Because of the central role of mass spectrometry (MS) as a detection technique in protein sciences, the term "mass tagging" was coined to describe the attachment of a label, which serves MS analysis and/or adds analytical value to the measurements. These so-called mass tags can be used for separation, enrichment, detection, and quantitation of peptides and proteins. In this context, cysteine is a frequent target for modifications because the thiol function can react specifically by nucleophilic substitution or addition. Furthermore, cysteines present natural modifications of biological importance and a low occurrence in the proteome that justify the development of strategies to specifically target them in peptides or proteins. In the present review, the mass-tagging methods directed to cysteine residues are comprehensively discussed, and the advantages and drawbacks of these strategies are addressed. Some concrete applications are given to underline the relevance of cysteine-tagging techniques for MS-based proteomics.     

Efficient Total Chemical Synthesis of 13C=18O Isotopomers of Human Insulin for Isotope‐Edited FTIR

Isotope‐edited two‐dimensional Fourier transform infrared spectroscopy (2 D FTIR) can potentially provide a unique probe of protein structure and dynamics. However, general methods for the site‐specific incorporation of stable ¹³C=¹⁸O labels into the polypeptide backbone of the protein molecule have not yet been established. Here we describe, as a prototype for the incorporation of specific arrays of isotope labels, the total chemical synthesis—via a key ester insulin intermediate—of 97 % enriched [(1‐¹³C=¹⁸O)Phe^B24] human insulin: stable‐isotope labeled at a single backbone amide carbonyl. The amino acid sequence as well as the positions of the disulfide bonds and the correctly folded structure were unambiguously confirmed by the X‐ray crystal structure of the synthetic protein molecule. In vitro assays of the isotope labeled [(1‐¹³C=¹⁸O)Phe^B24] human insulin showed that it had full insulin receptor binding activity. Linear and 2 D IR spectra revealed a distinct red‐shifted amide I carbonyl band peak at 1595 cm^?1 resulting from the (1‐¹³C=¹⁸O)Phe^B24 backbone label. This work illustrates the utility of chemical synthesis to enable the application of advanced physical methods for the elucidation of the molecular basis of protein function.     

Big label: categorizing the Web efficiently and accurately

Searching on the Web has never been an easy task. Even if semantic information is successfully inferred from a user query, how can we benefit from it? The most popular remedy today is to categorize the Web in advance. By gathering similar Web resources into a group, the search performance should increase even though search engines still have little idea about the semantics part. To categorize a set of Web resources according to meta-information associated with them, at first, one has to analyze the relationships between meta-information and Web resources. However, the result will be severely affected by the ambiguous nature of the Web. As a result, the goal of this research is to propose a new labeling method to enhance both the efficiency and accuracy of Web resources categorization.     

Layered Nanoprobe for Long‐Lasting Fluorescent Cell Label

A long‐lasting particle‐based fluorescent label is designed for extended cell imaging studies. This onion‐like nanoprobe is constructed through layer‐by‐layer fabrication technology. The nanoprobes are assembled with multiple layers of optically quenched polyelectrolytes, the fluorescence signal of which can be released later by intracellular proteolysis. Upon incubation with cells, the assembled nanoprobes are taken up efficiently. The tight packing and layered assembly of the quenched polyelectrolytes slow subsequent intracellular degradation, and then result in a prolonged intracellular fluorescence signal for up to 3 weeks with no noticeable toxicity.     

Consumer Awareness and Interest Toward Sodium Reduction Trends in Korea

Reduction of dietary sodium intake by lowering amount of sodium in foods is a global industry target. Quantitative information on current consumer knowledge of sodium reduction trends in Korea is unknown. The objective of this study was to quantify the consumer knowledge and awareness of sodium and salt reduction in foods and to characterize consumer interest in health labeling on the food package. Additionally, comparison of consumer knowledge status between Korea and United States was followed. Consumers (n = 289) participated in an internet survey designed to gauge consumer knowledge and attitudes toward dietary sodium, the sodium content in representative food products (n = 27), and their interest toward specific health claims, including sodium labeling. Questions regarding demographics as well as consumption characteristics were asked. Sodium knowledge index and saltiness belief index were calculated based on the number of correct responses regarding the salt level and sodium content in given food products. Kano analysis was conducted to determine the role of nutrition labels in consumer satisfaction with products. Current consumer knowledge on the sodium content in food products was high, and consumers were adept at matching the sodium content with the salty taste intensity of food products. Consumers’ knowledge of the relationship between diets high in sodium and an increased risk of developing previously reported sodium‐related diseases, such as hypertension, coronary heart disease, kidney disease, and stomach cancer, were also high. Information on the nutrition panel that influences the consumer satisfaction (trans‐fat, sodium, ingredient list, and country of origin) as well as adjective‐nutrition claim pairs that appeal positively to purchase intent of the product were identified.     

Photo-crosslinking: An Emerging Chemical Tool for Investigating Molecular Networks in Live Cells

Studying protein–protein interactions (PPIs) is useful for understanding cellular functions and mechanisms. Evaluating these PPIs under conditions as similar as possible to native conditions can be achieved using photo-crosslinking methods because of their on-demand ability to generate reactive species in situ by irradiation with UV light. Various fusion tag, metabolic incorporation, and amber codon suppression approaches using various crosslinkers containing aryl azide, benzophenone, and diazirines have been applied in live cells. Mass spectrometry and immunological techniques are used to identify crosslinked proteins based on their capture transient and context-dependent interactions. Herein we discuss various incorporation methods and crosslinkers that have been used for interactome mapping in live cells.     

Predicting how consumers perceive the naturalness of snacks: The usefulness of a simple index

For many consumers, it is important that food products be natural. Naturalness is a perceived property of food, but in the present study, we demonstrate that an objectively defined Food Naturalness Index (FNI) predicts perceived naturalness with a high degree of accuracy. A sample of 179 participants ranked 28 snacks, ranging from least natural to the most natural. Correlations on aggregated and individual levels suggest that perceived naturalness is strongly associated with the FNI. The food industry could therefore use the FNI to predict perceived naturalness during the product development phase of snacks, and it might also be a promising tool for regulating the use of naturalness claims in food marketing.     

靶向整合素α_vβ_3受体的新型RGDyC-PEG-PAMAM纳米探针的设计制备、~(131)I标记及其质量控制

本研究以具有优良生物学性能的聚酰胺-胺树状大分子(PAMAM)为纳米载体,将具有肿瘤靶向性的精氨酸-甘氨酸-天冬氨酸(RGD)与纳米载体相连,并通过放射性核素~(131)I进行标记,对标记物的体内外药效学性质进行评价,探讨将其应用于肿瘤特异显像和靶向治疗的可能性。从多肽化学修饰法角度设计精氨酸-甘氨酸-天冬氨酸-酪氨酸-半胱氨酸(RGDyC),利用点击化学法引入双功能基团PEG(NHS-PEG-MAL),采用"一锅两步"法制备RGDyC-PEG-PAMAM纳米复合物,通过核磁共振和紫外光谱进行表征确定产物,并检测纳米粒径分布和电位,用透射电镜(TEM)观察其形态大小及分布;进一步采用氯胺T法进行~(131)I标记,并测定标记率、标记物的稳定性及脂水分配系数。所设计的RGDyC-PEG-PAMAM纳米复合物制备产率为62.09%,~(131)I对其标记率为94.68%~98.87%,标记物在体外72h后放化纯大于80%,脂水分配系数lg P(正辛醇/水)为-1.59±0.09。所设计的RGDyC-PEG-PAMAM可采用氯胺T法成功完成~(131)I标记,制备与标记过程高效、简捷,标记物~(131)I-RGDyC-PEG-PAMAM具有良好稳定性和较高亲水性,成药性良好,为后期进一步考察体外肿瘤细胞摄取与生长抑制、评估人癌裸鼠异种移植瘤模型治疗及肿瘤显像等体内外药效学研究奠定了基础,~(131)I-RGDyC-PEG-PAMAM有可能作为一个新型SPECT探针应用于肿瘤特异显像与靶向治疗。