Screen‐printed biosensor for allergens

Allergen levels in indoor environments, leading to many diseases, eg asthma, rhinitis and conjunctivitis, affect a large and increasing fraction of the population. A quite effective and inexpensive method of a rough but very rapid overall assessment of total allergen level in the environment has been developed. The method involved estimation of protein in allergen extracts by screen‐printed electrodes using two different techniques. The biosensor comprised a rhodinised carbon working electrode, a silver/silver chloride reference electrode and a carbon counter electrode. In the first method the enzyme protease reacted with allergen protein to release amino acid, which produced hydrogen peroxide in the presence of amino acid oxidase. This was detected amperometrically. The second method used potassium bromide as electrolyte and the electrode was subjected to dual potential. Bromine, released due to electrolysis at higher potential, was consumed by the allergen protein at lower potential. In the first method, a unique technique was used to microencapsulate the enzyme protease and immobilise it on the surface of the electrode by in‐situ polymerisation to avoid contact with the amino acid oxidase. A total of seven allergens were tested and the results gave a good correlation with the standard protein measurement method. Environmental specimens from indoors, schools and workplaces can be evaluated for the aeroallergens produced by dust mites, animal hairs, cockroach debris, pollens, etc as a means of determining the exposure risk. Copyright © 2005 Society of Chemical Industry     

金融数据中心超6类综合布线的设计与施工

结合某金融机构数据中心使用超6类电子智能配线架的综合布线系统的实际经验,对超6类综合布线系统和电子智能配线管理系统的设计和现场施工进行介绍.该综合布线系统采用Commscope公司的SYSTIMAX综合布线系统产品,以及Commscope公司的iPatch电子智能配线管理系统.     

基于伪随机序列的Arnold加密算法

Arnold变换是一种经典的图像置乱算法。由于其具有周期性,导致密钥量不够。提出了一种改进的Arnold变换方法,即引入伪随机序列并利用安全哈希算法产生随机参数序列,将数字图像分块,并对每个块图像分别进行Arnold变换,最终得到一幅置乱图像。该算法有效地增加了密钥量,可以克服通过穷举分析等手段进行的攻击,增加了图像的安全性。     

食物致敏原表位定位技术的研究进展

食物致敏原是引起食物过敏的元凶，多为蛋白质。抗原表位是在抗原分子中与抗体反应或被抗原受体识别，并引发机体免疫应答的特殊化学基团。从表位水平认识食物致敏原，能揭示食物过敏的物质基础，为解决食物过敏问题提供精准的靶标。本文基于表位结构和定位方法的不同，介绍了食物致敏原表位定位技术的发展，并进一步展望了致敏原表位信息对于改进食物过敏鉴定技术和低致敏食物加工方法的应用前景。     

Isolation of recombinant antibody fragments (scFv) by phage display technology for detection of almond allergens in food products

Tree nut allergies are considered an important health issue in developed countries. To comply with the regulations on food labeling, reliable allergen detection methods are required. In this work we isolated almond-specific recombinant antibody fragments (scFv) from a commercial phage display library bypassing the use of live animals, hence being consistent with the latest policies on animal welfare. To this end an iterative selection procedure employing the Tomlinson I phage display library and a crude almond protein extract was carried out. Two different almond-specific scFv (named PD1F6 and PD2C9) were isolated after two rounds of biopanning, and an indirect phage ELISA was implemented to detect the presence of almond protein in foodstuffs. The isolated scFvs demonstrated to be highly specific and allowed detection of 40 ng mL⁻¹ and 100 ng mL⁻¹ of raw and roasted almond protein, respectively. The practical detection limit of the assay in almond spiked food products was 0.1 mg g⁻¹ (110–120 ppm). The developed indirect phage ELISA was validated by analysis of 92 commercial food products, showing good correlation with the results obtained by a previously developed real-time PCR method for the detection of almond in foodstuffs. The selected phage clones can be affinity maturated to improve their sensitivity and genetically engineered to be employed in different assay formats.     

植物蛋白肉产品品质评价及过敏原分析

为考察不同类别、不同品牌植物蛋白肉的品质,对市售18种植物蛋白肉产品进行感官评价及仪器检测,并对感官评价结果与仪器分析结果进行关联性分析,进一步探讨了过敏原的存在风险.通过外观、风味、口感等方面的指标可对植物蛋白鸡块、牛肉饼、肉馅品类有效评价产品像真性.全质构分析(TPA)参数中的咀嚼性和剪切力可以有效地评价感官指标,...     

Apple Allergy: The cDNA Sequence of the Major Allergen of Apple,Determined by Performing PCR with a Primer Based on the N-Terminal Amino Acid Sequence,is Highly Homologous to the Sequence of the Major Birch Pollen Allergen

Considering the known N-terminal amino acid sequence of the major apple allergen, a polymerase chain reaction (PCR) primer was selected to amplify cDNA encoding this protein. A single PCR product was obtained, cloned into Escherichia coli and subsequently sequenced. The missing 5′-end of the apple cDNA sequence was obtained by a 5′-RACE method. The cDNA sequence showed 72% identity with the coding region of one of the known isoforms of Bet v 1, the major allergen of birch pollen. The deduced amino acid sequence resulted in a 158-residue protein with a calculated molecular mass of 17·5 kDa and 63% amino acid sequence identity to Bet v 1. In addition, further protein alignments showed a high degree of identity with allergens from other tree pollens and some ‘pathogenesis-related proteins’ from food plants. According to international regulations the allergen was termed Mal d 1 for this protein, it being the first major allergen discovered and characterised in fruits of apple (Malus domestica).     

食物过敏原检测与调控研究进展

食品过敏已成为一个重要的食品质量和安全问题,对食品加工行业构成挑战,并影响消费者的健康。一方面,从食品加工行业的角度来看,食品原料成分、外源添加剂和加工形式的多样性使得现代食品加工中过敏原的存在更加复杂。此外,由于缺乏过敏原识别和有效的检测与评价系统,导致目前食品过敏原筛选与检测、跟踪与预测、干预与控制的理论和技术存在严重不足;另一方面,从公共卫生的角度来看,满足消费者对包括食物过敏原在内的不同类型原料来源的知情权,提高政府的公信力和人民的满意度也成为当务之急;此外,随着人们接触的食物种类越来越多,食物过敏的发生概率也越来越高,日趋复杂化、广域化和严重化的食物过敏所带来的食品安全健康问题已很难避免。鉴于此,针对大健康背景下日益严重的食品过敏安全问题,本综述介绍了食物过敏原的检测方法,总结了食物过敏原消减与控制技术,阐述了低致敏性食品以及抗过敏活性物质,综述了目前食物过敏原口服免疫治疗进展,旨在为预防和控制食物过敏,保障食物过敏患者的身体健康提供依据。     

Food allergy,a summary of eight cases in the UK criminal and civil courts: effective last resort for vulnerable consumers?

Food allergy has a forensic context. The authors describe eight cases in the UK courts involving fatalities, personal injury or criminal non‐compliance with food law from mainly ‘grey’ literature sources. The potentially severe consequences for people with food allergy of contraventions of labelling law have led to enforcement action up to criminal prosecution for what might otherwise be regarded as ‘trivial’ non‐compliance. The authors suggest there should be central collation of such cases. Non‐compliances should be followed up in a more rapid and robust manner. Evidence of fraud in the catering supply chain supports recent calls for zero tolerance of food fraud. Businesses must guard against gaps in allergen management, for which there are readily available sources of training and guidance, but also against fraudulent substitution in the supply chain, about which training and guidance should be developed. New allergen labelling legislation and case law appear to place responsibility on food businesses even for the forensically problematic area of allergen cross‐contamination. The courts can be an effective last resort for vulnerable consumers; however, there is evidence of knowledge and skill gaps in both the investigation and prosecution of potentially serious incidents of food allergen mismanagement and mislabelling. Thorough investigation of food allergy deaths is required with a tenacious and skilled approach, including early realisation that samples of the food and/or stomach contents from a post mortem examination should be retained and analysed. The supply chain must be rigorously examined to find out where adulteration or contamination with the fatal allergen occurred. © 2014 Society of Chemical Industry