农药残留检测关键用酶固定化研究进展

为保障消费者食用安全,迫切需要研发农产品和食品中的农药残留快速检测技术.酶抑制法检测是目前农药残留快速检测技术中的主要研究方向之一,而酶的固定化是用基于酶抑制法原理对农药残留检测研究中的重要步骤.通过物理或化学的方法高效地将酶固定于载体上,同时保持酶的催化活性是开发各类基于酶抑制法检测农药残留传感器的关键.本文将从固定...     

Some contributions of signal detection theory to the analysis of stimulus control in animals

This paper reviews some applications of Signal Detection Theory (SDT) to the quantitative analysis of non-human animal discrimination. The basic detection model is briefly outlined and the separation of sensitivity and bias is illustrated. Several other applications and ideas are reviewed, including the rating method, some implications of signal and criterion variance, and the measurement of 'guesses' not encompassed by standard SDT. The conceptual framework and analytic tools of SDT help to clarify processes underlying stimulus control and provide direction to more complete process models.     

Aptasensors for biosecurity applications

Nucleic acid (aptasensors) have found steadily increased utility and application over the past decade. In particular, aptamers have been touted as a valuable complement to and, in some cases, replacement for antibodies owing to their structural and functional robustness as well as their ease in generation and synthesis. They are thus attractive for biosecurity applications (e.g. pathogen detection) and are especially well suited because their in vitro generation process does not require infection of any host systems. Herein we provide a brief overview of the aptamers generated against pathogens and toxins over the past few years. In addition, a few recently described detection platforms using aptamers and potentially suitable applications for biosecurity will be discussed.     

Survey of recent advances in analytical applications of immunoaffinity chromatography

Methods that use immunoaffinity chromatography (IAC) for sample preparation or detection are becoming increasingly popular as tools in the analysis of biological and nonbiological compounds. This paper presents an overview of immunoaffinity chromatography and examines some recent developments of this technique in analytical applications. The emphasis is placed on HPLC-based IAC methods or those that combine IAC with other instrumental techniques; however, novel approaches that employ low-performance IAC columns for chemical quantitation are also considered. Particular applications that are examined include (1) the use of IAC in the direct detection of analytes, (2) the extraction of samples by IAC prior to on- or off-line detection by other methods, (3) the use of IAC in chromatographic-based immunoassays, and (4) the development of postcolumn reactors based on IAC for the detection of analytes as they elute from other types of chromatographic columns. The advantages and limitations for each approach are considered. In addition, a summary is provided of reports in the literature that have used IAC for these various formats.     

Microfluidic bio-particle manipulation for biotechnology

Microfluidics and lab-on-a-chip technology offers unique advantages for the next generation devices for diagnostic therapeutic applications. For chemical, biological and biomedical analysis in microfluidic systems, there are some fundamental operations such as separation, focusing, filtering, concentration, trapping, detection, sorting, counting, washing, lysis of bio-particles, and PCR-like reactions. The combination of these operations led to the complete analysis systems for specific applications. Manipulation of the bio-particles is the key ingredient for these applications. Therefore, microfluidic bio-particle manipulation has attracted a significant attention from the academic community. Considering the size of the bio-particles and the throughput of the practical applications, manipulation of the bio-particles is a challenging problem. Different techniques are available for the manipulation of bio-particles in microfluidic systems. In this review, some of the techniques for the manipulation of bio-particles; namely hydrodynamic based, electrokinetic-based, acoustic-based, magnetic-based and optical-based methods have been discussed. The comparison of different techniques and the recent applications regarding the microfluidic bio-particle manipulation for different biotechnology applications are presented. Finally, challenges and the future research directions for microfluidic bio-particle manipulation are addressed.     

核酸定量检测方法研究进展

核酸相关的研究和应用广泛存在于各个学科领域,与之相关的核酸定量检测技术越来越受到研究人员的重视。本文对目前实验室广泛采用的和近几年进展迅速的核酸定量方法(包括紫外分光光度法、荧光染料法、实时荧光定量PCR法、数字PCR法等)进行介绍,着重阐述其检测原理和优缺点,为研究人员今后进行相关研究提供参考。     

Surface enhanced Raman scattering for narcotic detection and applications to chemical biology

Raman spectroscopy is rapidly finding favour for applications in the life science because of the ease with which it can be used to extract significant data from tissue and cells. However, the Raman effect is an inherently weak effect, which hinders the analysis of low concentration analytes. Raman sensitivity can be improved via the surface enhanced Raman scattering (SERS) effect. In SERS, Raman spectra are dramatically amplified when a molecule is adsorbed onto nano-roughened noble metal surfaces such as silver and gold. The degree of enhancement enables single-molecule detection, which offers the potential for the unambiguous identification of analytes at concentrations that are useful in both a forensic and a chemical biology context. Here we discuss some of the practical applications of SERS to both low-level narcotic detection, and how this can be applied to chemical biology.     

Immunosensors for detection of pesticide residues

Immunosensors are biosensors that use antibodies or antigens as the specific sensing element and provide concentration-dependent signals. There is great potential in the applications of immunosensing technologies for rapid detection of pesticide residues in food and environment. This paper presents an overview of various transduction systems, such as electrochemical, optical, piezoelectric, and nanomechanics methods, which have been reported in the literature in the design and fabrication of immunosensors for pesticide detection. Various immobilization protocols used for formation of a biorecognition interface are also discussed. In addition, techniques of regeneration, signal amplification, miniaturization, and antibodies are evaluated for the development and applications of these immunosensors. It can be concluded that despite some limitations of the immunosensing technologies, these immuosensors for pesticide monitoring are becoming more and more relevant in environmental and food analysis.     

Applications of rapid-scanning multichannel detectors in chromatography : Plenary lecture

A review of progress in the field of multichannel detection in column and thin-layer chromatography is presented, together with some novel applications of a computer-based, linear photodiode array UV—visible spectrophotometer for detection in high-performance liquid chromatography (HPLC). Computer-aided methods for simultaneous monitoring of the elution profile at three wavelengths with automatic peak detection and capture of UV spectra are described. The continuous calculation of absorbance ratios during elution is discussed as an index of peak homogeneity. A novel technique for the enhancement of qualitative identification in HPLC, based on transformation of captured spectra to the second derivative or to the decadic logarithm, is proposed. These developments are exemplified by a model system of diacetylmorphine and its principal metabolites and degradation products, morphine and 6-acetylmorphine. The potential utility of three-dimensional projections of (A,ν,t) data is discussed in the context of pharmaceutical, bioanalytical and forensic applications.     

RAPID METHODS FOR ASSESSING MICROBIOLOGICAL QUALITY OF FOODS

Over the last four decades, many novel methods for the detection and enumeration of microorganisms in foods have been developed. This article briefly reviews some of these and discusses some of their applications.     

Use of PCR in the field

Polymerase chain reaction (PCR) represents a powerful new technology with a variety of field applications. While most of these are still experimental, implementation of PCR-based detection of Onchocerca volvulus in black flies, and subspecific differentiation strongly suggest that potential problems can be overcome. Because of high sensitivity and specificity, PCR provides in some cases the only means to address central parasitological questions, and may well become the 'gold standard' by which other diagnostic techniques are measured. In spite of these advantages, routine implementation of PCR,at present,requires transportation of samples to a central facility for processing, and personnel whose technical competence is high. In addition, reagents are expensive. Robert Barker here weighs up these considerations with regard to the potential utility of PCR assays for some applications.     

邻位连接技术：一种新的高灵敏度蛋白质检测技术

蛋白质组学(proteomics)诞生以来,高效准确的蛋白质检测技术受到越来越多的关注.最近 ,一种高灵敏度的蛋白质检测技术,邻位连接技术(proximity ligation assay, PLA)被建 立.该技术采用核酸适体(aptamer)或单/多克隆抗体 核酸复合物作为邻位连接探针(proximity probes).当一对邻位探针同时识别同一个目标蛋白分子时,它们将在空间位置上相互临近,通过连接反应形成一段可扩增的DNA标签序列,该标签序列能够反映待测蛋白的种类及浓度.该技术将对蛋白质的检测转变为对DNA核酸序列的检测,实现了特殊蛋白质的检测,定量及定位.文章从该方法的产生背景,发展过程,原理以及探针制备等方面对该方法进行了系统的介绍,列举了该方法的几种重要应用,并对该方法在蛋白质组学研究领域的应用前景进行了展望.     

Quantitative determination of histamine metabolites by capillary gas chromatography

A method using capillary gas chromatography is described for the determination of histamine and eight of its basic and acid metabolites in a single biological sample of serum, urine, or gastric juice. Ion-exchange chromatography and extraction with organic solvents are used for isolation and purification, and gas chromatography for identification and quantitation. The heptafluorobutyryl derivatives of histamine and some basic metabolites are compatible with nitrogen-phosphorus and electron capture detection modes and offer an excellent sensitivity (detection limit 0.1 pmol with electron capture). The acid metabolites are quantitated after esterification. The linearity range, the sensitivity, a partial study of reproducibility and typical chromatograms show that the method is adaptable to a variety of applications.     

Fast Fight Detection

Action recognition has become a hot topic within computer vision. However, the action recognition community has focused mainly on relatively simple actions like clapping, walking, jogging, etc. The detection of specific events with direct practical use such as fights or in general aggressive behavior has been comparatively less studied. Such capability may be extremely useful in some video surveillance scenarios like prisons, psychiatric centers or even embedded in camera phones. As a consequence, there is growing interest in developing violence detection algorithms. Recent work considered the well-known Bag-of-Words framework for the specific problem of fight detection. Under this framework, spatio-temporal features are extracted from the video sequences and used for classification. Despite encouraging results in which high accuracy rates were achieved, the computational cost of extracting such features is prohibitive for practical applications. This work proposes a novel method to detect violence sequences. Features extracted from motion blobs are used to discriminate fight and non-fight sequences. Although the method is outperformed in accuracy by state of the art, it has a significantly faster computation time thus making it amenable for real-time applications.     

“Toehold Switches; a foothold for Synthetic Biology”

Toehold switches are de novo designed riboregulators that contain two RNA components interacting through linear-linear RNA interactions, regulating the gene expression. These are highly versatile, exhibit excellent orthogonality, wide dynamic range, and are highly programmable, so can be used for various applications in synthetic biology. In this review, we summarized and discussed the design characteristics and benefits of toehold switch riboregulators over conventional riboregulators. We also discussed applications and recent advancements of toehold switch riboregulators in various fields like gene editing, DNA nanotechnology, translational repression, and diagnostics (detection of microRNAs and some pathogens). Toehold switches, therefore, furnished advancement in synthetic biology applications in various fields with their prominent features.     

Determination of sulfated biogenic amines: emphasis on dopamine sulfate isomers

Investigations concerning the specific conjugates of dopamine (DA) in the body have been hampered by the lack of specific and sensitive methodology for their detection. Because there is increasing interest in the occurrence and measurement of sulfated metabolites of DA and the other catecholamines (CA) norepinephrine and epinephrine, reliable methods for the detection and quantitation of these compounds in biological samples are needed. This paper reviews recently developed methods for the measurement of the two sulfate conjugates of DA in the body, DA-3-O-sulfate and DA-4-O-sulfate. The methods are sensitive enough for most, if not all, routine applications relating to DA sulfate. With minor modifications, some of the methods should be applicable to measurement of sulfate conjugates of many other electrochemically active compounds, such as other CA or indoles, their metabolites, and some drugs and metabolites.     

Osmium ammine: Review of current applications to visualize DNA in electron microscopy

Summary— This review has been collectively written. The contribution of the authors is mentioned for each part. References have been grouped at the end of the review. The objective of this review is to outline the principle of the method for electron microscopy, to emphasize the major applications and recent developments of this technique for DNA detection and finally to compare this technique with some other methods of DNA detection.     

Circulating tumor cells in the early detection of human cancers

Cancer is a severe disease with high morbidity and mortality globally. Thus, early detection is emerging as an important topic in modern oncology. Although the strategies for early detection have developed rapidly in recent decades, they remain challenging due to the subtle symptoms in the initial stage of the primary tumor. Currently, tumor biomarkers, imaging, and specific screening tests are widely used in various cancer types; however, each method has limitations. The harms are even overweight against the benefits in some cases. Therefore, early detection approaches should be improved urgently. Liquid biopsy, for now, is a convenient and non-invasive way compared to the traditional tissue biopsy in screening and early diagnosis. Circulating tumor cells (CTCs) are vital in liquid biopsy and play a central role in tumor dissemination and metastases. They have promising potential as cancer biomarkers in early detection. This review updates the knowledge of the biology of CTC; it also highlights the CTC enrichment technologies and their applications in the early detection of several human cancers.     

Use of ultrabright LEDs for the determination of static and time-resolved florescence information of liquid and solid crude oil samples

Ultrabright light emitting diodes (LEDs) are an inexpensive alternative to laser diodes (LDs) and other short wavelength emitting light sources. They have a high stability, a long lifetime, and a very low power consumption. A large number of publications are already available for fluorescence applications using this type of LEDs. Most of them are describing fluorescence intensity measurements. Only some of them are dealing with time-resolved methods, like single photon timing. LED modulation fluorometry is a very recent application, which can also be used for environmental investigations, like the detection of polycyclic aromatic hydrocarbons (PAHs). This article demonstrates the possible application of ultrabright LEDs for the time-resolved fluorescence detection of crude oil contaminated samples.