Ricin is a toxin that can be easily extracted from seeds of Ricinus communis plants. Ricin is considered to be a major bio-threat as it can be freely and easily acquired in large quantities. A deliberate release of such toxin in civilian populations would very likely overwhelm existing public health systems, resulting in public fear and social unrest. There is currently no commercially available or FDA-approved prophylaxis such as vaccines, or therapeutic antitoxins or antidotes, available for ricin intoxication. Patient treatment is typically supportive care based on symptoms, often designed to reinforce the body’s natural response. This paper describes the development and validation of a robust ELISA test kit, which can be used to screen for ricin in biological specimens such as whole blood and faeces. Faecal specimens are shown in this study to have better diagnostic sensitivity and a wider diagnostic window compared to whole blood. From these results, it is concluded that faeces is the most suitable clinical specimen for diagnosis of ricin poisoning via the oral route. The ELISA test kit can also detect ricin in environmental samples. An advantage of this ELISA kit over other commercial off-the-shelf (COTS) detection kits currently on the market that are developed to screen environmental samples only is its ability to diagnose ricin poisoning from clinical specimens as well as detect ricin from environmental samples. 相似文献
The catalytic hydrogenation of CO was studied over Mn- and/or Fe-promoted Rh/γ-Al2O3 catalysts. The catalysts were characterized by means of XRD, BET, H2-TPR·H2-TPD, XPS and DRIFTS. CO hydrogenation results showed that the doubly Mn- and Fe-promoted Rh/γ-Al2O3 catalysts exhibited superior catalytic activity and better ethanol selectivity. The DRIFTS results showed that Mn promoter stabilized the adsorbed CO on Rh+ and Fe stabilized adsorbed CO on Rh+ and Rh0, especially Rh0. The fact that doubly Mn- and Fe-promoted Rh/γ-Al2O3 owned more (Rhx0–Rhy+)–O–Fe3+·(Fe2+) active species was proposed to be a crucial factor accounting for its higher ethanol selectivity. 相似文献
An isothermal cross-priming amplification (CPA) assay for Agrobacterium tumefaciens nopaline synthase terminator (T-Nos) was established and investigated in this work. A set of six specific primers, recognizing eight distinct regions on the T-Nos sequence, was designed. The CPA assay was performed at a constant temperature, 63 °C, and detected by real-time fluorescence. The results indicated that real-time fluorescent CPA had high specificity, and the limit of detection was 1.06?×?103 copies of rice genomic DNA, which could be detected in 40 min. Comparison of real-time fluorescent CPA and conventional polymerase chain reaction (PCR) was also performed. Results revealed that real-time fluorescent CPA had a comparable sensitivity to conventional real-time PCR and had taken a shorter time. In addition, different contents of genetically modified (GM)-contaminated rice seed powder samples were detected for practical application. The result showed real-time fluorescent CPA could detect 0.5 % GM-contaminated samples at least, and the whole reaction could be finished in 35 min. Real-time fluorescent CPA is sensitive enough to monitor labeling systems and provides an attractive method for the detection of GMO.
Recombinant human erythropoietin (rhEPO) has been extensively used as a pharmaceutical product for treating anemia. Glycosylation of rhEPO affects the biological activity, immunogenicity, pharmacokinetics, and in-vivo clearance rate of rhEPO. Characterization of the glycosylation status of rhEPO is of great importance for quality control. In this study, we established a fast and comprehensive approach for reliable characterization and relative quantitation of rhEPO glycosylation, which combines multiple-enzyme digestion, hydrophilic-interaction chromatography (HILIC) enrichment of glycopeptides, and tandem mass spectrometry (MS) analysis. The N-linked and O-linked intact glycopeptides were analyzed with high-resolution and high-accuracy (HR–AM) mass spectrometry using an Orbitrap. In total, 74 intact glycopeptides from four glycosylation sites at N24, N38, N83, and O126 were identified, with the simultaneous determination of peptide sequences and glycoform compositions. The extracted ion chromatograms based on the HR–AM data enabled relative quantification of glycoforms. Our results could be extended to quality control of rhEPO or could help establish detection approaches for glycosylation of other proteins. Graphical Abstract
The widespread use of pesticides induces heavy adverse effects on human health,especially for the pregnant women and the newborns.In this study,a screening method has been developed for the determination of multi-pesticides in maternal and umbilical cord sera.All pesticides in sera were collected using solid phase extraction(SPE),and analyzed by gas chromatography-quadrupole time of flight mass spectrometry(GC-QTOF MS).To set up the quality criteria,a database of 50 pesticides was created and the accurate masses of 3 up to 5 representative ions with their intensity ratios were included for each pesticide.In addition,a novel"identification points"(IPs)system relying on the accurate MS1 and MS2 spectra was used to interpret the data for each suspected pesticide.The methodology was then applied to a pair of maternal and umbilical cord sera.A total of six pesticide residues were screened out successfully.In conclusion,GC-QTOF MS combined with an accurate mass database seemed to be one of the most efficient tools for systematic pesticide analysis. 相似文献
In this paper Cu3Mo2O9 nanosheet was prepared by a hydrothermal method and further used to investigate the direct electrochemistry of hemoglobin (Hb) with a carbon ionic liquid electrode (CILE) as the substrate electrode. Hb was mixed with Cu3Mo2O9 nanosheet and cast on the CILE surface with chitosan (CTS) as the film-forming material. UV-vis and FT-IR spectroscopic results showed that Hb remained in its native structure in the composite film. Direct electron transfer of Hb on the modified electrode was realized with a pair of well-defined quasi-reversible redox waves that appeared on cyclic voltammograms. The redox peak potential appeared at ?0.252 V (Epc) and ?0.141 V (Epa), respectively, with the formal peak potential calculated as ?0.196 V, which was the characteristic of electroactive center of Hb heme Fe(III)/Fe(II). The result could be attributed to the presence of Cu3Mo2O9 nanosheet on the electrode surface that was of benefit for the protein orientation and promoted direct electron transfer between the redox active center of Hb and the substrate electrode. The CTS/Cu3Mo2O9–Hb/CILE showed good electrocatalytic ability in reducing different substrates such as trichloroacetic acid, H2O2 and O2, with wider linear range and lower detection limit, thus exhibiting the potential application of the Cu3Mo2O9 nanosheet in third-generation electrochemical biosensors. 相似文献
A hypercrosslinked conjugated microporous polymer (HCMP‐1) with a robustly efficient absorption and highly specific sensitivity to mercury ions (Hg2+) is synthesized in a one‐step Friedel–Crafts alkylation of cost‐effective 2,4,6‐trichloro‐1,3,5‐triazine and dibenzofuran in 1,2‐dichloroethane. HCMP‐1 has a moderate Brunauer–Emmett–Teller specific surface (432 m2 g−1), but it displays a high adsorption affinity (604 mg g−1) and excellent trace efficiency for Hg2+. The π–π* electronic transition among the aromatic heterocyclic rings endows HCMP‐1 a strong fluorescent property and the fluorescence is obviously weakened after Hg2+ uptake, which makes the hypercrosslinked conjugated microporous polymer a promising fluorescent probe for Hg2+ detection, owning a super‐high sensitivity (detection limit 5 × 10−8 mol L−1).
A highly living polymer with over 100 kg mol−1 molecular weight is very difficult to achieve by controlled radical polymerization since the unavoidable side reactions of irreversible radical termination and radical chain transfer to monomer reaction become significant. It is reported that over 500 kg mol−1 polystyrene with high livingness and low dispersity could be synthesized by a facile two‐stage reversible addition–fragmentation transfer emulsion polymerization. The monomer conversion reaches 90% within 10 h. High livingness of the product is ascribed to the extremely low initiator concentration and the chain transfer constant for monomer unexpectedly much lower than the well‐accepted values in the conventional radical polymerization. The two‐stage monomer feeding policy much decreases the dispersity of the product.
