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A Simple, Fast and Portable Method for Electrochemical Detection of Adenine Released by Ricin Enzymatic Activity. Toxins (Basel) 2021; 13:toxins13040238. [PMID: 33810228 PMCID: PMC8066795 DOI: 10.3390/toxins13040238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
International authorities classify ricin toxin present in castor seed as a potential agent for use in bioterrorism. Therefore, the detection, identification, and characterization of ricin in various sample matrices are considered necessary actions for risk assessment during a suspected exposure. This study reports a portable electrochemical assay for detecting active ricin based on the adenine electro-oxidation released from herring sperm DNA substrate by its catalytic action. Also, kinetic parameters were calculated, and the values were Km of 3.14 µM and Kcat 2107 min−1. A linear response was found in optimized experimental conditions for ricin concentrations ranging from 8 to 120 ng/mL, and with a detection limit of 5.14 ng/mL. This proposed detection strategy emphasizes the possibility of field detection of active ricin in food matrices and can be applied to other endonucleolytic activities.
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2
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Influence of Food Matrices on the Stability and Bioavailability of Abrin. Toxins (Basel) 2018; 10:toxins10120502. [PMID: 30513721 PMCID: PMC6316575 DOI: 10.3390/toxins10120502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/19/2018] [Accepted: 11/23/2018] [Indexed: 11/16/2022] Open
Abstract
Abrin, a highly toxic plant toxin, is a potential bioterror weapon. Work from our laboratory and others have shown that abrin is highly resistant to both thermal and pH inactivation methods. We sought to evaluate the effectiveness of selected food processing thermal inactivation conditions against abrin in economically important food matrices (whole milk, non-fat milk, liquid egg, and ground beef). The effectiveness of toxin inactivation was measured via three different assays: (1) In vitro cell free translation (CFT) assay, (2) Vero cell culture cytotoxicity; and the in vivo mouse intraperitoneal (ip) bioassay. For both whole and non-fat milk, complete inactivation was achieved at temperatures of ≥80 °C for 3 min or 134 °C for 60 s, which were higher than the normal vat/batch pasteurization or the high temperature short time pasteurization (HTST). Toxin inactivation in liquid egg required temperatures of ≥74 °C for 3 min higher than suggested temperatures for scrambled eggs (22% solids) and plain whole egg. Additionally, the ground beef (80:20%) matrix was found to be inhibitory for full toxin activity in the mouse bioassay while retaining some activity in both the cell free translation assay and Vero cell culture cytotoxicity assay.
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3
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Abrin Toxicity and Bioavailability after Temperature and pH Treatment. Toxins (Basel) 2017; 9:toxins9100320. [PMID: 29027937 PMCID: PMC5666367 DOI: 10.3390/toxins9100320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/07/2017] [Accepted: 10/10/2017] [Indexed: 11/17/2022] Open
Abstract
Abrin, one of most potent toxins known to man, is derived from the rosary pea (jequirity pea), Abrus precatorius and is a potential bioterror weapon. The temperature and pH stability of abrin was evaluated with an in vitro cell free translation (CFT) assay, a Vero cell culture cytotoxicity assay, and an in vivo mouse bioassay. pH treatment of abrin had no detrimental effect on its stability and toxicity as seen either in vitro or in vivo. Abrin exposure to increasing temperatures did not completely abrogate protein translation. In both the cell culture cytotoxicity model and the mouse bioassay, abrin’s toxic effects were completely abrogated if the toxin was exposed to temperatures of 74 °C or higher. In the cell culture model, 63 °C-treated abrin had a 30% reduction in cytotoxicity which was validated in the in vivo mouse bioassay with all mice dying but with a slight time-to-death delay as compared to the non-treated abrin control. Since temperature inactivation did not affect abrin’s ability to inhibit protein synthesis (A-chain), we hypothesize that high temperature treatment affected abrin’s ability to bind to cellular receptors (affecting B-chain). Our results confirm the absolute need to validate in vitro cytotoxicity assays with in vivo mouse bioassays.
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4
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An International Proficiency Test to Detect, Identify and Quantify Ricin in Complex Matrices. Toxins (Basel) 2015; 7:4987-5010. [PMID: 26703726 PMCID: PMC4690109 DOI: 10.3390/toxins7124859] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 11/08/2015] [Accepted: 11/16/2015] [Indexed: 12/14/2022] Open
Abstract
While natural intoxications with seeds of Ricinus communis (R. communis) have long been known, the toxic protein ricin contained in the seeds is of major concern since it attracts attention of those intending criminal, terroristic and military misuse. In order to harmonize detection capabilities in expert laboratories, an international proficiency test was organized that aimed at identifying good analytical practices (qualitative measurements) and determining a consensus concentration on a highly pure ricin reference material (quantitative measurements). Sample materials included highly pure ricin as well as the related R. communis agglutinin (RCA120) spiked into buffer, milk and meat extract; additionally, an organic fertilizer naturally contaminated with R. communis shred was investigated in the proficiency test. The qualitative results showed that either a suitable combination of immunological, mass spectrometry (MS)-based and functional approaches or sophisticated MS-based approaches alone successfully allowed the detection and identification of ricin in all samples. In terms of quantification, it was possible to determine a consensus concentration of the highly pure ricin reference material. The results provide a basis for further steps in quality assurance and improve biopreparedness in expert laboratories worldwide.
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Falenski A, Weiser AA, Thöns C, Appel B, Käsbohrer A, Filter M. Towards a Food Safety Knowledge Base Applicable in Crisis Situations and Beyond. BIOMED RESEARCH INTERNATIONAL 2015; 2015:830809. [PMID: 26247028 PMCID: PMC4515494 DOI: 10.1155/2015/830809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/24/2014] [Indexed: 11/17/2022]
Abstract
In case of contamination in the food chain, fast action is required in order to reduce the numbers of affected people. In such situations, being able to predict the fate of agents in foods would help risk assessors and decision makers in assessing the potential effects of a specific contamination event and thus enable them to deduce the appropriate mitigation measures. One efficient strategy supporting this is using model based simulations. However, application in crisis situations requires ready-to-use and easy-to-adapt models to be available from the so-called food safety knowledge bases. Here, we illustrate this concept and its benefits by applying the modular open source software tools PMM-Lab and FoodProcess-Lab. As a fictitious sample scenario, an intentional ricin contamination at a beef salami production facility was modelled. Predictive models describing the inactivation of ricin were reviewed, relevant models were implemented with PMM-Lab, and simulations on residual toxin amounts in the final product were performed with FoodProcess-Lab. Due to the generic and modular modelling concept implemented in these tools, they can be applied to simulate virtually any food safety contamination scenario. Apart from the application in crisis situations, the food safety knowledge base concept will also be useful in food quality and safety investigations.
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Affiliation(s)
- Alexander Falenski
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Armin A. Weiser
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Christian Thöns
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Bernd Appel
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Annemarie Käsbohrer
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Matthias Filter
- Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany
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6
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Jackson LS, Triplett OA, Tolleson WH. Influence of yogurt fermentation and refrigerated storage on the stability of protein toxin contaminants. Food Chem Toxicol 2015; 80:101-107. [DOI: 10.1016/j.fct.2015.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 10/23/2022]
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7
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Brandon DL, Adams LM. Milk matrix effects on antibody binding analyzed by enzyme-linked immunosorbent assay and biolayer interferometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:3593-3598. [PMID: 25822824 DOI: 10.1021/acs.jafc.5b01136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Biolayer interferometry (BLI) was employed to study the impact of the milk matrix on the binding of ricin to asialofetuin (ASF) and to antibodies. This optical sensing platform used ligands immobilized covalently or via biotin-streptavidin linkage, and the results were compared to those obtained by enzyme-linked immunosorbent assay (ELISA). In sandwich ELISA, the binding of ricin to ASF was dramatically decreased when galactose was present during the analyte or detection antibody binding step. Low concentrations of milk (1%, v/v) produced a similar reduction in ricin binding to ASF but not to a high-affinity monoclonal antibody (mAb), increasing the dissociation rate of ASF-ricin complexes up to 100-fold. The effect of milk on the binding of ricin to ASF was ascribable to dialyzable factors, and milk sugar can account for these effects. The use of high-affinity mAbs in ELISA effectively limits the milk matrix effect on ricin analysis.
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Affiliation(s)
- David L Brandon
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, United States Department of Agriculture (USDA) Agricultural Research Service, 800 Buchanan Street, Albany, California 94710, United States
| | - Lisa M Adams
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, United States Department of Agriculture (USDA) Agricultural Research Service, 800 Buchanan Street, Albany, California 94710, United States
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Zengin A, Tamer U, Caykara T. Fabrication of a SERS based aptasensor for detection of ricin B toxin. J Mater Chem B 2015; 3:306-315. [DOI: 10.1039/c4tb00290c] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Poly(N-acryoyl-l-valine, AVAL) brushes were grafted onto a silicon substrateviaRAFT polymerization, and then ricin B aptamer was covalently conjugated to the poly(AVAL) brushes to recognize and detect ricin B toxinviaSERS-based sandwich assay.
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Affiliation(s)
- Adem Zengin
- Faculty of Science
- Department of Chemistry
- Gazi University
- Ankara
- Turkey
| | - Ugur Tamer
- Faculty of Pharmacy
- Department of Analytical Chemistry
- Gazi University
- Ankara
- Turkey
| | - Tuncer Caykara
- Faculty of Science
- Department of Chemistry
- Gazi University
- Ankara
- Turkey
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9
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Brandon DL, Adams LM, Yang LL, Korn AM. Antibody Interactions withRicinus communisAgglutinins Studied by Biolayer Interferometry. ANAL LETT 2014. [DOI: 10.1080/00032719.2014.886693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Thermal inactivation reaction rates for ricin are influenced by pH and carbohydrates. Food Chem Toxicol 2013; 58:116-23. [DOI: 10.1016/j.fct.2013.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/05/2013] [Indexed: 11/20/2022]
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11
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McKeon TA, Bo Shim K, He X. Reducing the toxicity of castor seed meal through processing treatments. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2013. [DOI: 10.1016/j.bcab.2012.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Brandon DL, Korn AM, Yang LL. Immunosorbent analysis of ricin contamination in milk using colorimetric, chemiluminescent and electrochemiluminescent detection. FOOD AGR IMMUNOL 2013. [DOI: 10.1080/09540105.2012.753515] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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13
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Brandon DL. Electrochemiluminescence immunosorbent assay of ricin in ground beef: biotinylated capture antibodies and matrix effects. FOOD AGR IMMUNOL 2012. [DOI: 10.1080/09540105.2011.629315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
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14
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Real-time cytotoxicity assay for rapid and sensitive detection of ricin from complex matrices. PLoS One 2012; 7:e35360. [PMID: 22532852 PMCID: PMC3330811 DOI: 10.1371/journal.pone.0035360] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Accepted: 03/15/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In the context of a potential bioterrorist attack sensitive and fast detection of functionally active toxins such as ricin from complex matrices is necessary to be able to start timely countermeasures. One of the functional detection methods currently available for ricin is the endpoint cytotoxicity assay, which suffers from a number of technical deficits. METHODOLOGY/FINDINGS This work describes a novel online cytotoxicity assay for the detection of active ricin and Ricinus communis agglutinin, that is based on a real-time cell electronic sensing system and impedance measurement. Characteristic growth parameters of Vero cells were monitored online and used as standardized viability control. Upon incubation with toxin the cell status and the cytotoxic effect were visualized using a characteristic cell index-time profile. For ricin, tested in concentrations of 0.06 ng/mL or above, a concentration-dependent decrease of cell index correlating with cytotoxicity was recorded between 3.5 h and 60 h. For ricin, sensitive detection was determined after 24 h, with an IC50 of 0.4 ng/mL (for agglutinin, an IC50 of 30 ng/mL was observed). Using functionally blocking antibodies, the specificity for ricin and agglutinin was shown. For detection from complex matrices, ricin was spiked into several food matrices, and an IC50 ranging from 5.6 to 200 ng/mL was observed. Additionally, the assay proved to be useful in detecting active ricin in environmental sample materials, as shown for organic fertilizer containing R. communis material. CONCLUSIONS/SIGNIFICANCE The cell-electrode impedance measurement provides a sensitive online detection method for biologically active cytotoxins such as ricin. As the cell status is monitored online, the assay can be standardized more efficiently than previous approaches based on endpoint measurement. More importantly, the real-time cytotoxicity assay provides a fast and easy tool to detect active ricin in complex sample matrices.
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15
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Evaluation and comparison of three enzyme-linked immunosorbent assay formats for the detection of ricin in milk and serum. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2012. [DOI: 10.1016/j.bcab.2011.08.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Brandon DL, Korn AM, Yang LL. Detection of Ricin Contamination in Liquid Egg by Electrochemiluminescence Immunosorbent Assay. J Food Sci 2012; 77:T83-8. [DOI: 10.1111/j.1750-3841.2012.02627.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Worbs S, Köhler K, Pauly D, Avondet MA, Schaer M, Dorner MB, Dorner BG. Ricinus communis intoxications in human and veterinary medicine-a summary of real cases. Toxins (Basel) 2011; 3:1332-72. [PMID: 22069699 PMCID: PMC3210461 DOI: 10.3390/toxins3101332] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 09/26/2011] [Accepted: 09/30/2011] [Indexed: 12/11/2022] Open
Abstract
Accidental and intended Ricinus communis intoxications in humans and animals have been known for centuries but the causative agent remained elusive until 1888 when Stillmark attributed the toxicity to the lectin ricin. Ricinus communis is grown worldwide on an industrial scale for the production of castor oil. As by-product in castor oil production ricin is mass produced above 1 million tons per year. On the basis of its availability, toxicity, ease of preparation and the current lack of medical countermeasures, ricin has gained attention as potential biological warfare agent. The seeds also contain the less toxic, but highly homologous Ricinus communis agglutinin and the alkaloid ricinine, and especially the latter can be used to track intoxications. After oil extraction and detoxification, the defatted press cake is used as organic fertilizer and as low-value feed. In this context there have been sporadic reports from different countries describing animal intoxications after uptake of obviously insufficiently detoxified fertilizer. Observations in Germany over several years, however, have led us to speculate that the detoxification process is not always performed thoroughly and controlled, calling for international regulations which clearly state a ricin threshold in fertilizer. In this review we summarize knowledge on intended and unintended poisoning with ricin or castor seeds both in humans and animals, with a particular emphasis on intoxications due to improperly detoxified castor bean meal and forensic analysis.
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Affiliation(s)
- Sylvia Worbs
- Centre for Biological Security, Microbial Toxins (ZBS3), Robert Koch-Institut, Nordufer 20, Berlin 13353, Germany; (S.W.); (D.P.); (M.B.D.)
| | - Kernt Köhler
- Institute of Veterinary Pathology, Justus Liebig University Giessen, Frankfurter Street 96, Giessen 35392, Germany;
| | - Diana Pauly
- Centre for Biological Security, Microbial Toxins (ZBS3), Robert Koch-Institut, Nordufer 20, Berlin 13353, Germany; (S.W.); (D.P.); (M.B.D.)
| | - Marc-André Avondet
- Biology and Chemistry Section, Federal Department of Defence, Civil Protection and Sports DDPS SPIEZ LABORATORY, Austrasse 1, Spiez CH-3700, Switzerland; (M.-A.A.); (M.S.)
| | - Martin Schaer
- Biology and Chemistry Section, Federal Department of Defence, Civil Protection and Sports DDPS SPIEZ LABORATORY, Austrasse 1, Spiez CH-3700, Switzerland; (M.-A.A.); (M.S.)
| | - Martin B. Dorner
- Centre for Biological Security, Microbial Toxins (ZBS3), Robert Koch-Institut, Nordufer 20, Berlin 13353, Germany; (S.W.); (D.P.); (M.B.D.)
| | - Brigitte G. Dorner
- Centre for Biological Security, Microbial Toxins (ZBS3), Robert Koch-Institut, Nordufer 20, Berlin 13353, Germany; (S.W.); (D.P.); (M.B.D.)
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Lamont EA, He L, Warriner K, Labuza TP, Sreevatsan S. A single DNA aptamer functions as a biosensor for ricin. Analyst 2011; 136:3884-95. [PMID: 21748194 DOI: 10.1039/c1an15352h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of microorganisms or toxins as weapons of death and fear is not a novel concept; however, the modes by which these agents of bioterrorism are deployed are increasingly clever and insidious. One mechanism by which biothreats are readily disseminated is through a nation's food supply. Ricin, a toxin derived from the castor bean plant, displays a strong thermostability and remains active at acidic and alkaline pHs. Therefore, the CDC has assigned ricin as a category B reagent since it may be easily amendable as a deliberate food biocontaminate. Current tools for ricin detection utilize enzymatic activity, immunointeractions and presence of castor bean DNA. Many of these tools are confounded by complex food matrices, display a limited dynamic range of detection and/or lack specificity. Aptamers, short RNA and single stranded DNA sequences, have increased affinity to their selected receptors, experience little cross-reactivity to other homologous compounds and are currently being sought after as biosensors for bacterial contaminants in food. This paper describes the selection and characterization of a single, dominant aptamer, designated as SSRA1, against the B-chain of ricin. SSRA1 displays one folding conformation that is stable across 4-63 °C (ΔG = -5.05). SSRA1 is able to concentrate at least 30 ng mL(-1) of ricin B chain from several liquid food matrices and outcompetes a currently available ELISA kit and ricin aptamer. Furthermore, we show detection of 25 ng mL(-1) of intact ricin A-B complex using SSRA1 combined with surface enhanced Raman scattering technique. Thus, SSRA1 would serve well as pre-analytical tool for processing of ricin from liquid foods to aid current diagnostics as well as a sensor for direct ricin detection.
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Affiliation(s)
- Elise A Lamont
- Veterinary Population Medicine, University of Minnesota, Room 301E, 1971 Commonwealth Avenue, Saint Paul, Minnesota, USA
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Brandon DL. Detection of ricin contamination in ground beef by electrochemiluminescence immunosorbent assay. Toxins (Basel) 2011; 3:398-408. [PMID: 22069715 PMCID: PMC3202826 DOI: 10.3390/toxins3040398] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 03/31/2011] [Accepted: 03/31/2011] [Indexed: 11/23/2022] Open
Abstract
Ricin is a highly toxic protein present in the seeds of Ricinus communis (castor), grown principally as a source of high quality industrial lubricant and as an ornamental. Because ricin has been used for intentional poisoning in the past and could be used to contaminate food, there is a need for analytical methodology to detect ricin in food matrices. A monoclonal antibody-based method was developed for detecting and quantifying ricin in ground beef, a complex, fatty matrix. The limit of detection was 0.5 ng/g for the electrochemiluminescence (ECL) method and 1.5 ng/g for enzyme-linked immunosorbent assay (ELISA). The detection of nanogram per gram quantities of ricin spiked into retail samples of ground beef provides approximately 10,000-fold greater sensitivity than required to detect a toxic dose of ricin (>1 mg) in a 100 g sample.
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Affiliation(s)
- David L Brandon
- Foodborne Contaminants Research Unit, Western Regional Research Center, USDA Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA.
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20
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McGrath SC, Schieltz DM, McWilliams LG, Pirkle JL, Barr JR. Detection and Quantification of Ricin in Beverages Using Isotope Dilution Tandem Mass Spectrometry. Anal Chem 2011; 83:2897-905. [DOI: 10.1021/ac102571f] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara C. McGrath
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, United States
| | - David M. Schieltz
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, United States
| | - Lisa G. McWilliams
- Battelle (on Contract with the Division of Laboratory Sciences), 4770 Buford Highway, Atlanta, Georgia 30341, United States
| | - James L. Pirkle
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, United States
| | - John R. Barr
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, United States
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21
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He X, McMahon S, Henderson TD, Griffey SM, Cheng LW. Ricin toxicokinetics and its sensitive detection in mouse sera or feces using immuno-PCR. PLoS One 2010; 5:e12858. [PMID: 20877567 PMCID: PMC2943921 DOI: 10.1371/journal.pone.0012858] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Accepted: 08/23/2010] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Ricin (also called RCA-II or RCA(60)), one of the most potent toxins and documented bioweapons, is derived from castor beans of Ricinus communis. Several in vitro methods have been designed for ricin detection in complex food matrices in the event of intentional contamination. Recently, a novel Immuno-PCR (IPCR) assay was developed with a limit of detection of 10 fg/ml in a buffer matrix and about 10-1000-fold greater sensitivity than other methods in various food matrices. METHODS AND FINDINGS In order to devise a better diagnostic test for ricin, the IPCR assay was adapted for the detection of ricin in biological samples collected from mice after intoxication. The limit of detection in both mouse sera and feces was as low as 1 pg/ml. Using the mouse intravenous (iv) model for ricin intoxication, a biphasic half-life of ricin, with a rapid t(1/2)α of 4 min and a slower t(1/2)β of 86 min were observed. The molecular biodistribution time for ricin following oral ingestion was estimated using an antibody neutralization assay. Ricin was detected in the blood stream starting at approximately 6-7 h post- oral intoxication. Whole animal histopathological analysis was performed on mice treated orally or systemically with ricin. Severe lesions were observed in the pancreas, spleen and intestinal mesenteric lymph nodes, but no severe pathology in other major organs was observed. CONCLUSIONS The determination of in vivo toxicokinetics and pathological effects of ricin following systemic and oral intoxication provide a better understanding of the etiology of intoxication and will help in the future design of more effective diagnostic and therapeutic methods.
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Affiliation(s)
- Xiaohua He
- Foodborne Contaminants Research Unit, Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America
| | - Stephanie McMahon
- Foodborne Contaminants Research Unit, Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America
| | - Thomas D. Henderson
- Foodborne Contaminants Research Unit, Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America
| | - Stephen M. Griffey
- Comparative Pathology Lab, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Luisa W. Cheng
- Foodborne Contaminants Research Unit, Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America
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HE XIAOHUA, McMAHON STEPHANIE, McKEON THOMASA, BRANDON DAVIDL. Development of a Novel Immuno-PCR Assay for Detection of Ricin in Ground Beef, Liquid Chicken Egg, and Milk. J Food Prot 2010; 73:695-700. [DOI: 10.4315/0362-028x-73.4.695] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reliable, sensitive, and high-throughput methods are essential for food defense, to detect foodborne contaminants and to facilitate remediation and recovery from potential toxin-related incidents. Ricin is a protein toxin that has been used for intentional contamination of foods in the past. In this study, we developed procedures for quantification of ricin in foods using immuno-PCR (IPCR). The direct adsorption of ricin onto the wells of a microtitration plate was compared with indirect immobilization via a capture antibody (sandwich IPCR). The latter procedure provided much greater sensitivity. We also compared a protocol with the immunoassay and PCR conducted in a single plate to a two-step procedure in which the PCR was conducted in a second plate, following release and transfer of the DNA marker. The two-step procedure proved 1,000-fold more sensitive for ricin detection, so this format was used to detect ricin in spiked samples of ground beef, chicken egg, and milk, and the results were compared with those obtained from enzyme-linked immunosorbent assay (ELISA). The IPCR had a limit of detection of 10 pg/ml in chicken egg and milk samples and 100 pg/ml in ground beef extracts. Comparable ELISA results were in the 1 to 10 ng/ml range. Thus, IPCR affords sensitivity that is 10-fold greater in the ground beef matrix, 100-fold greater in the milk, and 1,000-fold greater in the egg matrix than the sensitivity obtained by ELISA. Further optimization of the sandwich IPCR was performed by comparing various antibody combinations. Among the four formats investigated, the pAb-pAb combination yielded the lowest limit of detection (10 fg/ml).
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Affiliation(s)
- XIAOHUA HE
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA
| | - STEPHANIE McMAHON
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA
| | - THOMAS A. McKEON
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA
| | - DAVID L. BRANDON
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA
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He X, Quiñones B, Carter JM, Mandrell RE. Validation of a cell-free translation assay for detecting shiga toxin 2 in bacterial culture. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:5084-5088. [PMID: 19489630 DOI: 10.1021/jf9002285] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A cell-free translation (CFT) assay for detecting Shiga toxin (Stx) at different levels of purity has been validated. The limits of detection for pure Stx2 (PStx2) and partially pure Stx2 (PPStx2) in water reached 20 and 3.5 pg/microL, respectively, without the artificial process of proteolytic activation and reduction of the pro-toxin. The specific detection of Stx2 was confirmed by a neutralization test using Stx2-specific mouse monoclonal antibody. This assay can be used for differentiation of Stx-producing Escherichia coli from non-Stx-producing E. coli. Four E. coli O157:H7 strains genotypically different for Stx were tested. The translational inhibition of Stx-producing E. coli was significantly higher than that of non-Stx-producing E. coli when bacterial culture supernatants were used for the analysis. Inhibition occurred even with supernatants diluted 1000-fold. The thermal stability of Stx2 was studied using the CFT assay, and significant differences were observed among three Stx2 preparations heated at 70 degrees C for 60 min. It was concluded that the CFT assay is a rapid, specific, and sensitive method for detecting Stx2 activity.
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Affiliation(s)
- Xiaohua He
- US Department of Agriculture, Western Regional Research Center, Agricultural Research Service, Albany, California 94710, USA.
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Brandon DL, Hernlem BJ. Development of monoclonal antibodies specific forRicinusagglutinins. FOOD AGR IMMUNOL 2009. [DOI: 10.1080/09540100802626487] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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