scholarly journals Display of Antigens on Polyester Inclusions Lowers the Antigen Concentration Required for a Bovine Tuberculosis Skin Test

2015 ◽  
Vol 23 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Natalie A. Parlane ◽  
Shuxiong Chen ◽  
Gareth J. Jones ◽  
H. Martin Vordermeier ◽  
D. Neil Wedlock ◽  
...  
Keyword(s):  
Skin Test ◽  
Bovine Tuberculosis ◽  
Low Cost ◽  
High Sensitivity ◽  
Content Type ◽  
Environmental Mycobacteria ◽  
Low Concentrations ◽  
Polyhydroxyalkanoate Synthase ◽  
Test Specificity ◽  
Tuberculosis Skin Test

ABSTRACTThe tuberculin skin test is the primary screening test for the diagnosis of bovine tuberculosis (TB), and use of this test has been very valuable in the control of this disease in many countries. However, the test lacks specificity when cattle have been exposed to environmental mycobacteria or vaccinated withMycobacterium bovisbacille Calmette-Guérin (BCG). Recent studies showed that the use of three or four recombinant mycobacterial proteins, including 6-kDa early secretory antigenic target (ESAT6), 10-kDa culture filtrate protein (CFP10), Rv3615c, and Rv3020c, or a peptide cocktail derived from those proteins, in the skin test greatly enhanced test specificity, with minimal loss of test sensitivity. The proteins are present in members of the pathogenicMycobacterium tuberculosiscomplex but are absent in or not expressed by the majority of environmental mycobacteria and the BCG vaccine strain. To produce a low-cost skin test reagent, the proteins were displayed at high density on polyester beads through translational fusion to a polyhydroxyalkanoate synthase that mediates the formation of antigen-displaying inclusions in recombinantEscherichia coli. Display of the proteins on the polyester beads greatly increased their immunogenicity, allowing for the use of very low concentrations of proteins (0.1 to 3 μg of mycobacterial protein/inoculum) in the skin test. Polyester beads simultaneously displaying all four proteins were produced in a single fermentation process. The polyester beads displaying three or four mycobacterial proteins were shown to have high sensitivity for detection ofM. bovis-infected cattle and induced minimal responses in animals exposed to environmental mycobacteria or vaccinated with BCG.

scholarly journals New Skin Test for Detection of Bovine Tuberculosis on the Basis of Antigen-Displaying Polyester Inclusions Produced by Recombinant Escherichia coli

2014 ◽  
Vol 80 (8) ◽  
pp. 2526-2535 ◽  
Author(s):  
Shuxiong Chen ◽  
Natalie A. Parlane ◽  
Jason Lee ◽  
D. Neil Wedlock ◽  
Bryce M. Buddle ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Skin Test ◽  
Skin Testing ◽  
Cross Reactivity ◽  
Pha Synthase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Content Type ◽  
Flight Mass Spectrometry ◽  
Environmental Mycobacteria ◽  
Test Specificity

ABSTRACTThe tuberculin skin test for diagnosing tuberculosis (TB) in cattle lacks specificity if animals are sensitized to environmental mycobacteria, as some antigens in purified protein derivative (PPD) prepared fromMycobacterium bovisare present in nonpathogenic mycobacteria. Three immunodominant TB antigens, ESAT6, CFP10, and Rv3615c, are present in members of the pathogenicMycobacterium tuberculosiscomplex but absent from the majority of environmental mycobacteria. These TB antigens have the potential to enhance skin test specificity. To increase their immunogenicity, these antigens were displayed on polyester beads by translationally fusing them to a polyhydroxyalkanoate (PHA) synthase which mediated formation of antigen-displaying inclusions in recombinantEscherichia coli. The most common form of these inclusions is poly(3-hydroxybutyric acid) (PHB). The respective fusion proteins displayed on these PHB inclusions (beads) were identified using tryptic peptide fingerprinting analysis in combination with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). The surface exposure and accessibility of antigens were assessed by enzyme-linked immunosorbent assay (ELISA). Polyester beads displaying all three TB antigens showed greater reactivity with TB antigen-specific antibody than did beads displaying only one TB antigen. This was neither due to cross-reactivity of antibodies with the other two antigens nor due to differences in protein expression levels between beads displaying single or three TB antigens. The triple-antigen-displaying polyester beads were used for skin testing of cattle and detected all cattle experimentally infected withM. boviswith no false-positive reactions observed in those sensitized to environmental mycobacteria. The results suggested applicability of TB antigen-displaying polyester inclusions as diagnostic reagents for distinguishing TB-infected from noninfected animals.

Modern nanobiotechnologies for efficient detection and remediation of mercury

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mulayam Singh Gaur ◽  
Rajni Yadav ◽  
Mamta Kushwah ◽  
Anna Nikolaevna Berlina
Keyword(s):  
Heavy Metals ◽  
Water Samples ◽  
Low Cost ◽  
High Sensitivity ◽  
Environmental Water ◽  
Mercury Ions ◽  
Content Type ◽  
Efficient Detection ◽  
Sensitivity And Selectivity ◽  
Selection Of

Purpose This information will be useful in the selection of materials and technology for the detection and removal of mercury ions at a low cost and with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. Design/methodology/approach Different nano- and bio-materials allowed for the development of a variety of biosensors – colorimetric, chemiluminescent, electrochemical, whole-cell and aptasensors – are described. The materials used for their development also make it possible to use them in removing heavy metals, which are toxic contaminants, from environmental water samples. Findings This review focuses on different technologies, tools and materials for mercury (heavy metals) detection and remediation to environmental samples. Originality/value This review gives up-to-date and systemic information on modern nanotechnology methods for heavy metal detection. Different recognition molecules and nanomaterials have been discussed for remediation to water samples. The present review may provide valuable information to researchers regarding novel mercury ions detection sensors and encourage them for further research/development.

scholarly journals Improved Skin Test for Differential Diagnosis of Bovine Tuberculosis by the Addition of Rv3020c-Derived Peptides

2012 ◽  
Vol 19 (4) ◽  
pp. 620-622 ◽  
Author(s):  
Gareth J. Jones ◽  
Adam Whelan ◽  
Derek Clifford ◽  
Mick Coad ◽  
H. Martin Vordermeier
Keyword(s):  
Differential Diagnosis ◽  
Skin Test ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Johne's Disease ◽  
Diagnostic Sensitivity ◽  
Bacillus Calmette Guerin ◽  
Content Type ◽  
The Face ◽  
Mycobacterial Antigens

ABSTRACTA peptide cocktail derived from the mycobacterial antigens ESAT-6, CFP-10, and Rv3615c allowed differentiation betweenMycobacterium bovis-infected and M. bovis bacillus Calmette-Guérin (BCG)-vaccinated cattle when used as a skin test reagent for a “DIVA” test (i.e., a test capable ofdifferentiatinginfected and uninfectedvaccinatedanimals). Addition of the antigen Rv3020c improves the diagnostic sensitivity without compromising specificity in the face of BCG or Johne's disease vaccination.

scholarly journals Assessment of a Protein Cocktail-Based Skin Test for Bovine Tuberculosis in a Double-Blind Field Test in Cattle

2013 ◽  
Vol 20 (4) ◽  
pp. 482-490 ◽  
Author(s):  
Ting Xin ◽  
Hong Jia ◽  
Jiabo Ding ◽  
Pingjun Li ◽  
Hongjun Yang ◽  
...  
Keyword(s):  
Tuberculin Skin Test ◽  
Skin Test ◽  
Bovine Tuberculosis ◽  
Relative Sensitivity ◽  
Skin Thickness ◽  
Double Blind ◽  
Content Type ◽  
Relative Specificity ◽  
Release Assay ◽  
Ifn Γ

ABSTRACTBovine tuberculosis (bTB) is a worldwide zoonosis caused mainly byMycobacterium bovis.The traditional diagnostic method used often is the tuberculin skin test, which uses bovine purified protein derivatives (PPD-B). However, it is difficult to maintain uniformity of PPD-B from batch to batch, and it shares common antigens with nonpathogenic environmental mycobacteria. To overcome these problems,M. bovis-specific antigens that showed good T cell stimulation, such as CFP-10, ESAT-6, Rv3615c, etc., have been used in the skin test, but there have been no large-scale clinical studies on these antigens. In this study, two combinations (CFP-10/ESAT-6/TB10.4 protein cocktail and CFP-10/ESAT-6/Rv3872/MPT63 protein cocktail) were developed and used as stimuli in the skin test. Cattle were double-blind tested to assess the efficiency of the protein cocktail-based skin tests. The results showed that the CFP-10/ESAT-6/TB10.4 protein cocktail-based skin test can differentiate TB-infected cattle fromMycobacterium avium-infected ones and that it shows a high degree of agreement with the traditional tuberculin skin test (κ = 0.8536) and gamma interferon (IFN-γ) release assay (κ = 0.8154). Compared to the tuberculin skin test, the relative sensitivity and relative specificity of the CFP-10/ESAT-6/TB10.4-based skin test were 87% and 97%, respectively., The relative sensitivity and relative specificity of the CFP-10/ESAT-6/TB10.4-based skin test were 93% and 92%, respectively, on comparison with the IFN-γ release assay. The correlation between the increases in skin thickness observed after the inoculation of stimuli was high (PPD-B versus CFP-10/ESAT-6/TB10.4, Spearmanrof 0.8435). The correlation between the optical density at 450 nm (OD450) obtained after blood stimulation with PPD-B and the increase in skin thickness observed after inoculation of the CFP-10/ESAT-6/TB10.4 protein cocktail was high (Spearmanr= 0.7335). Therefore, the CFP-10/ESAT-6/TB10.4-based skin test responses correlate to traditional measures of bovine TB evaluation, including skin test and gamma interferon release assay.

Formaldehyde sensing properties of ZnO-based hollow nanofibers

Sensor Review ◽  
2014 ◽  
Vol 34 (3) ◽  
pp. 327-334 ◽  
Author(s):  
Shaohong Wei ◽  
Youjuan Zhang ◽  
Meihua Zhou
Keyword(s):  
Low Cost ◽  
High Sensitivity ◽  
Diffraction Field ◽  
Formaldehyde Concentration ◽  
Hollow Nanofibers ◽  
Content Type ◽  
Sensing Properties ◽  
Electrospinning Method ◽  
Formaldehyde Sensing ◽  
Hollow Nanofiber

Purpose – The purpose of this paper is to synthesize SnO2–ZnO hollow nanofibers, study their sensing properties and introduce an attractive candidate for formaldehyde detection in practice. Design/methodology/approach – Pure and SnO2–ZnO hollow nanofibers were synthesized by electrospinning method and characterized via X-ray diffraction, field-emission scanning electron microscopy and Fourier transform infrared spectroscopy. The formaldehyde-sensing properties were investigated. Findings – The optimum performance was obtained at 260°C by the 14 at.% SnO2–ZnO hollow nanofiber sensor. The sensor could detect formaldehyde down to 0.1 ppm with rapid response–recovery time (4-6 s and 7-9 s, respectively), high sensitivity, good selectivity and stability. The relationship between the sensor’s sensitivity and formaldehyde concentration suggests that the adsorbed oxygen species on the sensor’s surface is O2−. The prominent sensing properties are attributed to the one dimensional hollow nanofiber structures and the promoting effects of SnO2. Practical implications – The sensor fabricated from 14 at.% SnO2–ZnO fibers exhibits excellent formaldehyde-sensing characteristics. It can be used for formaldehyde detection in practice. Social implications – The electrospinning method is a very simple and convenient method for fabricating hollow nanofibers and the sensing material is of low cost. Originality/value – To the best of the authors’ knowledge, studies on formaldehyde sensing of SnO2–ZnO hollow nanofibers have not been reported before.

scholarly journals A molecularly defined skin test reagent for the diagnosis of bovine tuberculosis compatible with vaccination against Johne’s Disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sonya Middleton ◽  
Sabine Steinbach ◽  
Michael Coad ◽  
Kevina McGill ◽  
Colm Brady ◽  
...  
Keyword(s):  
Skin Test ◽  
Recombinant Proteins ◽  
Bovine Tuberculosis ◽  
Synthetic Peptides ◽  
Blood Test ◽  
High Specificity ◽  
Active Components ◽  
Interferon Gamma Release Assays ◽  
Skin Responses

AbstractTuberculin Purified Protein Derivatives (PPDs) exhibit multiple limitations: they are crude extracts from mycobacterial cultures with largely unknown active components; their production depends on culture of mycobacteria requiring expensive BCL3 production facilities; and their potency depends on the technically demanding guinea pig assay. To overcome these limitations, we developed a molecularly defined tuberculin (MDT) by adding further antigens to our prototype reagent composed of ESAT-6, CFP-10 and Rv3615c (DIVA skin test, DST). In vitro screening using PBMC from infected and uninfected cattle shortlisted four antigens from a literature-based list of 18 to formulate the MDT. These four antigens plus the previously identified Rv3020c protein, produced as recombinant proteins or overlapping synthetic peptides, were formulated together with the three DST antigens into the MDT to test cattle experimentally and naturally infected with M. bovis, uninfected cattle and MAP vaccinated calves. We demonstrated significant increases in MDT-induced skin responses compared to DST in infected animals, whilst maintaining high specificity in unvaccinated or MAP vaccinated calves. Further, MDT can also be applied in in vitro blood-based interferon-gamma release assays. Thus, MDT promises to be a robust diagnostic skin and blood test reagent overcoming some of the limitations of PPDs and warrants full validation.

scholarly journals Sunflower-Like Nanostructure with Built-In Hotspots for Alpha-Fetoprotein Detection

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1197
Author(s):  
Xiaoyu Zhao ◽  
Aonan Zhu ◽  
Yaxin Wang ◽  
Yongjun Zhang ◽  
Xiaolong Zhang
Keyword(s):  
Rapid Detection ◽  
Clinical Medicine ◽  
Electromagnetic Coupling ◽  
Low Cost ◽  
Surface Enhanced Raman Spectroscopy ◽  
Alpha Fetoprotein ◽  
Low Concentrations ◽  
Surface Enhanced Raman ◽  
Active Substrate ◽  
Array Structures

In the present study, a sunflower-like nanostructure array composed of a series of synaptic nanoparticles and nanospheres was manufactured through an efficient and low-cost colloidal lithography technique. The primary electromagnetic field contribution generated by the synaptic nanoparticles of the surface array structures was also determined by a finite-difference time-domain software to simulate the hotspots. This structure exhibited high repeatability and excellent sensitivity; hence, it was used as a surface-enhanced Raman spectroscopy (SERS) active substrate to achieve a rapid detection of ultra-low concentrations of Alpha-fetoprotein (AFP). This study demonstrates the design of a plasmonic structure with strong electromagnetic coupling, which can be used for the rapid detection of AFP concentration in clinical medicine.

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

scholarly journals All-Dielectric Metasurface for Sensing Microcystin-LR

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1363
Author(s):  
Binze Ma ◽  
Ao Ouyang ◽  
Juechen Zhong ◽  
Pavel A. Belov ◽  
Ravindra Kumar Sinha ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bound States ◽  
High Sensitivity ◽  
Concentration Limit ◽  
Specific Recognition ◽  
Low Concentrations ◽  
Freshwater Bodies ◽  
Toxic Pollutant ◽  
Small Change ◽  
Dielectric Metasurface

Sensing Microcystin-LR (MC-LR) is an important issue for environmental monitoring, as the MC-LR is a common toxic pollutant found in freshwater bodies. The demand for sensitive detection method of MC-LR at low concentrations can be addressed by metasurface-based sensors, which are feasible and highly efficient. Here, we demonstrate an all-dielectric metasurface for sensing MC-LR. Its working principle is based on quasi-bound states in the continuum mode (QBIC), and it manifests a high-quality factor and high sensitivity. The dielectric metasurface can detect a small change in the refractive index of the surrounding environment with a quality factor of ~170 and a sensitivity of ~788 nm/RIU. MC-LR can be specifically identified in mixed water with a concentration limit of as low as 0.002 μg/L by a specific recognition technique for combined antigen and antibody. Furthermore, the demonstrated detection of MC-LR can be extended to the identification and monitoring of other analytes, such as viruses, and the designed dielectric metasurface can serve as a monitor platform with high sensitivity and high specific recognition capability.

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