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Nevídalová H, Michalcová L, Glatz Z. Capillary electrophoresis-based immunoassay and aptamer assay: A review. Electrophoresis 2020; 41:414-433. [PMID: 31975407 DOI: 10.1002/elps.201900426] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 12/31/2022]
Abstract
Over the last two decades, the group of techniques called affinity probe CE has been widely used for the detection and the determination of several types of biomolecules with high sensitivity. These techniques combine the low sample consumption and high separation power of CE with the selectivity of the probe to the target molecule. The assays can be defined according to the type of probe used: CE immunoassays, with an antibody as the probe, or aptamer-based CE, with an aptamer as the probe. Immunoassays are generally divided into homogeneous and heterogeneous groups, and homogeneous variant can be further performed in competitive or noncompetitive formats. Interacting partners are free in solution at homogeneous assay, as opposed to heterogeneous analyses, where one of them is immobilized onto a solid support. Highly sensitive fluorescence, chemiluminescence or electrochemical detections were typically used in this type of study. The use of the aptamers as probes has several advantages over antibodies such as shorter generation time, higher thermal stability, lower price, and lower variability. The aptamer-based CE technique was in practice utilized for the determination of proteins in biological fluids and environmentally or clinically important small molecules. Both techniques were also transferred to microchip. This review is focused on theoretical principles of these techniques and a summary of their applications in research.
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Affiliation(s)
- Hana Nevídalová
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lenka Michalcová
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Zdeněk Glatz
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
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Zou D, Zhang D, Liu S, Zhao B, Wang H. Interplay of binding stoichiometry and recognition specificity for the interaction of MBD2b protein and methylated DNA revealed by affinity capillary electrophoresis coupled with laser-induced fluorescence analysis. Anal Chem 2014; 86:1775-82. [PMID: 24422445 DOI: 10.1021/ac4036636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The methyl-CpG binding domain (MBD) family proteins can specifically bind methylated DNA sequences and thereby mediate gene transcription. In this study, we used neutral capillary electrophoresis coupled with laser-induced fluorescence to investigate the interactions of DNA and MBD2b, a model MBD family protein with the highest affinity. For this purpose, we synthesized 13 double-stranded oligonucleotides of varying length (20 bp to 80 bp) and of varying methylation density. The sequences of these oligonucleotides were adapted from a frequently methylated promoter region of human p16(INK4a) gene. We demonstrate that multiple MBD2b proteins can bind to one DNA molecule with a DNA length-dependent binding stoichiometry. Each MBD2b protein can occupy 20 nucleotides in a bound DNA molecule regardless of the methylation status of DNA. By binding multiple MBD2b proteins (up to four protein molecules) to one dsDNA molecule (80 bp), methylated and unmethylated DNA were bound at similar percentages. Although the total amount of the DNA-MBD2b complexes increases with increasing DNA length for both unmethylated and methylated DNA, the DNA-MBD2b complexes of 1:1 display more than 10-fold higher affinity for methylated DNA (e.g., 40 bp DNA) accompanying a 20-fold lower dissociation rate constant. Hence, our study clarifies for the first time that the specificity of MBD2b to methylated DNA decreases as more MBD2b monomers binding to the same region of DNA. Additionally, this study opens a new venue to improve MBD protein-based assays for detecting DNA methylation.
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Affiliation(s)
- Dandan Zou
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 China
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Analytical methods in DNA and protein adduct analysis. Anal Bioanal Chem 2010; 398:2563-72. [DOI: 10.1007/s00216-010-4217-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 09/10/2010] [Accepted: 09/12/2010] [Indexed: 10/19/2022]
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Simionato AVC, Carrilho E, Maggi Tavares MF. CE-MS and related techniques as a valuable tool in tumor biomarkers research. Electrophoresis 2010; 31:1214-1226. [DOI: 10.1002/elps.200900671] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Wang C, Li T, Wang Z, Feng F, Wang H. Quantitative study of stereospecific binding of monoclonal antibody to anti-benzo(a)pyrene diol epoxide-N2-dG adducts by capillary electrophoresis immunoassay. J Chromatogr A 2010; 1217:2254-61. [DOI: 10.1016/j.chroma.2010.02.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/03/2010] [Accepted: 02/12/2010] [Indexed: 10/19/2022]
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Wang Z, Lu M, Wang X, Yin R, Song Y, Le XC, Wang H. Quantum Dots Enhanced Ultrasensitive Detection of DNA Adducts. Anal Chem 2009; 81:10285-9. [DOI: 10.1021/ac9021105] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhixin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - Meiling Lu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - Xiaoli Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - Ruichuan Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - Yuling Song
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - X. Chris Le
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
| | - Hailin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, T6G 2G3, AB, Canada
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Ultra-performance liquid chromatography–tandem mass spectrometry for rapid and highly sensitive analysis of stereoisomers of benzo[a]pyrene diol epoxide–DNA adducts. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:2104-12. [DOI: 10.1016/j.jchromb.2009.05.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 05/27/2009] [Accepted: 05/30/2009] [Indexed: 11/21/2022]
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Shen S, Lee J, Cullen WR, Le XC, Weinfeld M. Arsenite and its mono- and dimethylated trivalent metabolites enhance the formation of benzo[a]pyrene diol epoxide-DNA adducts in Xeroderma pigmentosum complementation group A cells. Chem Res Toxicol 2009; 22:382-90. [PMID: 19146383 DOI: 10.1021/tx800335p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Recently, inorganic arsenite (iAs(III)) and its mono- and dimethylated metabolites have been examined for their interference with the formation and repair of benzo[a]pyrene diol epoxide (BPDE)-induced DNA adducts in human cells (Schwerdtle, ., Walter, I., and Hartwig, A. (2003) DNA Repair 2, 1449 - 1463). iAs(III) and monomethylarsonous acid (MMA(III)) were found to be able to enhance the formation of BPDE-DNA adducts, whereas dimethylarsinous acid (DMA(III)) had no enhancing effect at all. The anomaly manifested by DMA(III) prompted us to further investigate the effects of the three trivalent arsenic species on the formation of BPDE-DNA adducts. Use of a nucleotide excision repair (NER)-deficient Xeroderma pigmentosum complementation group A cell line (GM04312C) allowed us to dissect DNA damage induction from DNA repair and to examine the effects of arsenic on the formation of BPDE-DNA adducts only. At concentrations comparable to those used in the study by Schwerdtle et al., we found that each of the three trivalent arsenic species was able to enhance the formation of BPDE-DNA adducts with the potency in a descending order of MMA(III) > DMA(III) > iAs(III), which correlates well with their cytotoxicities. Similar to iAs(III), DMA(III) modulation of reduced glutathione (GSH) or total glutathione S-transferase (GST) activity could not account for its enhancing effect on DNA adduct formation. Additionally, the enhancing effects elicited by the trivalent arsenic species were demonstrated to be highly time-dependent. Thus, although our study made use of short-term assays with relatively high doses, our data may have meaningful implications for carcinogenesis induced by chronic exposure to arsenic at low doses encountered environmentally.
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Affiliation(s)
- Shengwen Shen
- Department of Laboratory Medicine and Pathology, 10-102 Clinical Sciences Building, University of Alberta, Edmonton, Alberta, Canada
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LeBlanc A, Shen S, Lew K, Weinfeld M, Chris Le X. Detection of benzo(a)pyrene diol epoxide-DNA adducts in mononuclear white blood cells by CE immunoassay and its application to studying the effect of glutathione depletion. Electrophoresis 2009; 30:1558-63. [DOI: 10.1002/elps.200800391] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wang C, Feng F, Wang Z, Li T, Le XC, Wang H. Synthesis and Characterization of DNA Fluorescent Probes Containing a Single Site-Specific Stereoisomer of anti-Benzo[a]pyrene Diol Epoxide-N2-dG. Chem Res Toxicol 2009; 22:676-82. [DOI: 10.1021/tx800419p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chao Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Feng Feng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Zhixin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Tao Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - X. Chris Le
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Hailin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
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Wang Z, Wang C, Yin J, Li T, Song M, Lu M, Wang H. Focusing and stabilization of bis-intercalating dye-DNA complexes for high-sensitive CE-LIF DNA analysis. Electrophoresis 2008; 29:4454-62. [DOI: 10.1002/elps.200800230] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Zhao Q, Li XF, Shao Y, Le XC. Aptamer-based affinity chromatographic assays for thrombin. Anal Chem 2008; 80:7586-93. [PMID: 18759461 DOI: 10.1021/ac801206s] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Affinity chromatographic assays for thrombin were developed using two aptamers as affinity ligands. The efficient capture and step elution of thrombin with NaClO4 enabled the determination of thrombin by using either absorbance or fluorescence detection. Preconcentration of thrombin on the affinity column improved the detection limit of thrombin to 0.1 nM. Using an aptamer for the fibrinogen-binding site of thrombin and a second aptamer for the heparin-binding site, a sandwich chromatographic assay was developed, showing improved selectivity of thrombin detection and eliminating the need for labeling thrombin in the sample. The increased local concentration of aptamers immobilized on monolithic columns favored the formation of aptamer-thrombin complexes, resulting in improved retention and detection of thrombin at trace levels.
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Affiliation(s)
- Qiang Zhao
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada T6G 2G3
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Shen S, Lee J, Weinfeld M, Le XC. Attenuation of DNA damage-induced p53 expression by arsenic: a possible mechanism for arsenic co-carcinogenesis. Mol Carcinog 2008; 47:508-18. [PMID: 18085531 DOI: 10.1002/mc.20406] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Inhibition of DNA repair processes has been suggested as one predominant mechanism in arsenic co-genotoxicity. However, the underlying mode of action responsible for DNA repair inhibition by arsenic remains elusive. To further elucidate the mechanism of repair inhibition by arsenic, we examined the effect of trivalent inorganic and methylated arsenic metabolites on the repair of benzo(a)pyrene diol epoxide (BPDE)-DNA adducts in normal human primary fibroblasts and their effect on repair-related protein expression. We observed that monomethylarsonous acid (MMA(III)) was the most potent inhibitor of the DNA repair. MMA(III) did not change the expression levels of some key repair proteins involved upstream of the dual incision in the global nucleotide excision repair (NER) pathway, including p48, XPC, xeroderma pigmentosum complementation group A (XPA), and p62-TFIIH. However, it led to a marked impairment of p53 induction in response to BPDE treatment. The abrogated p53 expression translated into reduced p53 DNA-binding activity, suggesting a possibility of downregulating downstream repair genes by p53. A p53-null cell line failed to exhibit the inhibitory effect of MMA(III) on NER, implicating a role for p53 in the NER inhibition by MMA(III). Further investigation revealed that MMA(III) dramatically inhibited p53 phosphorylation at serine 15, implying that MMA(III) destabilized p53 by inhibiting its phosphorylation. Because p53 is required for proficient global NER, our data suggest that arsenic inhibits NER through suppressing p53 induction in response to DNA damage in cells with normal p53 gene expression.
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Affiliation(s)
- Shengwen Shen
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
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Preparation, identification and analysis of stereoisomeric anti-benzo[a]pyrene diol epoxide–deoxyguanosine adducts using phenyl liquid chromatography with diode array, fluorescence and tandem mass spectrometry detection. J Chromatogr A 2008; 1183:119-28. [DOI: 10.1016/j.chroma.2008.01.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 01/07/2008] [Accepted: 01/09/2008] [Indexed: 11/23/2022]
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Fundador E, Rusling J. Detection of labeled abasic sites in damaged DNA by capillary electrophoresis with laser-induced fluorescence. Anal Bioanal Chem 2007; 387:1883-90. [PMID: 17206410 DOI: 10.1007/s00216-006-1041-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/19/2006] [Accepted: 11/22/2006] [Indexed: 11/29/2022]
Abstract
Removal of nucleobases from the DNA backbone leads to the formation of abasic sites. The rate of abasic site formation is significantly increased for chemically damaged nucleobases. Thus, abasic sites serve as general biomarkers for the quantification of DNA damage. Herein, we show that capillary electrophoresis with laser-induced fluorescence (CE-LIF) can be used to detect the amount of abasic sites with very high sensitivity. For proof of concept, DNA was incubated with methylmethane sulfonate (MMS) and the damaged bases were removed by incubation at 80 degrees C. The resulting abasic sites were then tagged with a fluorescent aldehyde-reactive probe (FARP). The DNA was precipitated with ethanol, and then analyzed by CE-LIF. CE-LIF and HPLC analysis shows that the fluorescently tagged DNA (DNA-FARP) had a peak area directly proportional to the amount of N-7 methyl guanines. The CE-LIF method had a detection limit of 1.2 abasic sites per 1,000,000 bases or ca. 20 attomoles of abasic sites. This provides a general method for detecting DNA damage that is not only faster but also has comparable or better sensitivity than the alternative ELISA-like method.
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Affiliation(s)
- Erwin Fundador
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
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Shen S, Lee J, Sun X, Wang H, Weinfeld M, Le XC. Elevation of cellular BPDE uptake by human cells: a possible factor contributing to co-carcinogenicity by arsenite. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:1832-7. [PMID: 17185271 PMCID: PMC1764144 DOI: 10.1289/ehp.9284] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
BACKGROUND Arsenite (iAsIII) can promote mutagenicity and carcinogenicity of other carcinogens. Considerable attention has focused on interference with DNA repair by inorganic arsenic, especially the nucleotide excision repair (NER) pathway, whereas less is known about the effect of arsenic on the induction of DNA damage by other agents. OBJECTIVES We examined how arsenic modulates DNA damage by other chemicals. METHODS We used an NER-deficient cell line to dissect DNA damage induction from DNA repair and to examine the effects of iAsIII on the formation of benzo[a]pyrene diol epoxide (BPDE)-DNA adducts. RESULTS We found that pretreatment with iAsIII at subtoxic concentrations (10 microM) led to enhanced formation of BPDE-DNA adducts. Reduced glutathione levels, glutathione S-transferase activity and chromatin accessibility were also measured after iAsIII treatment, but none of these factors appeared to account for the enhanced formation of DNA adducts. However, we found that pretreatment with iAsIII increased the cellular uptake of BPDE in a dose-dependent manner. CONCLUSIONS Our results suggest that iAsIII enhanced the formation of BPDE-DNA adducts by increasing the cellular uptake of BPDE. Therefore, the ability of arsenic to increase the bioavailability of other carcinogens may contribute to arsenic co-carcinogenicity.
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MESH Headings
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/chemistry
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/pharmacokinetics
- 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/pharmacology
- Arsenites/pharmacology
- Carcinogens/chemistry
- Carcinogens/pharmacokinetics
- Carcinogens/pharmacology
- Cell Line
- Cell Line, Transformed
- Chromatin/metabolism
- DNA Adducts/drug effects
- DNA Damage/drug effects
- DNA Repair/drug effects
- Glutathione/metabolism
- Humans
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Affiliation(s)
- Shengwen Shen
- Department of Public Health Sciences and Department of Laboratory Medicine and Pathology and
| | - Jane Lee
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Xuejun Sun
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Hailin Wang
- Department of Public Health Sciences and Department of Laboratory Medicine and Pathology and
| | - Michael Weinfeld
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - X. Chris Le
- Department of Public Health Sciences and Department of Laboratory Medicine and Pathology and
- Address correspondence to X.C. Le, Department of Public Health Sciences and Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alberta, Canada T6G 2G3. Telephone: (780) 492-6416. Fax: (780) 492-7800. E-mail:
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MacDonald AM, Lucy CA. Highly efficient protein separations in capillary electrophoresis using a supported bilayer/diblock copolymer coating. J Chromatogr A 2006; 1130:265-71. [PMID: 16777117 DOI: 10.1016/j.chroma.2006.05.042] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 05/06/2006] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
A surfactant/polymer wall coating consisting of the doubly chained cationic surfactant dimethyldioctadecylammonium bromide (DODAB) and polyoxyethylene (POE) 40 stearate is investigated. The coating is formed by simply rinsing a capillary with a solution containing DODAB and POE 40 stearate. The resultant coating is semi-permanent--demonstrating stable electroosmotic flow (EOF) even after a 60 min high pressure rinse with buffer. The EOF (-0.45+/-(0.23) x 10(-4) cm(2) V(-1) s(-1) at pH 7.4) is suppressed by more than a factor of ten compared to that observed for DODAB alone. Model protein mixtures were separated over a pH range of 3-10 with efficiencies of up to greater than 1 million plates/m for the basic proteins cytochrome c, lysozyme, ribonuclease A and alpha-lactalbumin, and the acidic proteins insulin chain A, trypsin inhibitor, and alpha-chymotrypsinogen A. Migration time reproducibility was 0.5-4.0% from run to run and 0.6-4.3% from day to day. Protein recoveries with this coating ranged from 84% to 97%.
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Affiliation(s)
- Amy M MacDonald
- Department of Chemistry, University of Alberta, Gunning/Lemieux Chemistry Centre, Edmonton, Alta., Canada T6G 2G2
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Affiliation(s)
- Qiang Zhao
- Department of Public Health Sciences, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
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Miao H, Rubakhin SS, Sweedler JV. Confirmation of peak assignments in capillary electrophoresis using immunoprecipitation. Application to D-aspartate measurements in neurons. J Chromatogr A 2005; 1106:56-60. [PMID: 16199049 DOI: 10.1016/j.chroma.2005.09.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 09/14/2005] [Accepted: 09/16/2005] [Indexed: 10/25/2022]
Abstract
Capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection is a powerful tool for analysis of samples ranging from tissue extracts to single cells. However, accurate peak identification in electropherograms is challenging when complex biological samples are analyzed, as often matching a migration time between an analyte and corresponding standard may be insufficient to confirm the peak's identity. A method which combines single-step immunoprecipitation and CE-LIF analysis for investigation of the chiral amino acids in single cells and small tissue samples is demonstrated. D-Aspartate (D-Asp) has been reported in the central nervous system of the invertebrate neurobiological model Aplysia californica. In order to confirm the identity of D-Asp signal in the complex electropherograms of nerve tissue extracts and individual neurons, anti-D-Asp serum, preincubated with L-Asp conjugate, is added to the sample. This selectively binds the free D-Asp, creating an antibody-antigen complex with a migration time similar to that of antibody alone, but not that of D-Asp. The complete disappearance of the putative D-Asp peak confirms its identity and validates that there are no other detectable analytes co-migrating with D-Asp in the electropherogram.
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Affiliation(s)
- Hai Miao
- Department of Chemistry, University of Illinois, Champaign, School of Chemical Sciences, 600 South Mathews Avenue 63-5, Urbana, IL 61801, USA
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Le XC, Pavski V, Wang H. 2002 W.A.E. McBryde Award Lecture Affinity recognition, capillary electrophoresis, and laser-induced fluorescence polarization for ultrasensitive bioanalysis. CAN J CHEM 2005. [DOI: 10.1139/v04-175] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The combination of affinity recognition, capillary electrophoresis (CE), laser-induced fluorescence (LIF), and fluorescence polarization for the ultrasensitive determination of compounds of biological interest is described. Competitive immunoassays using CELIF eliminate the need for fluorescently labeling trace analytes of interest and are particularly useful for determination of small molecules, such as cyclosporine, gentamicin, vancomycin, and digoxin. Fluorescence polarization allows for differentiation of the antibody-bound from the unbound small molecules. Noncompetitive affinity CELIF assays are shown to be highly effective in the determination of biomarkers for DNA damage and HIV-1 infection. An antibody (or aptamer) is used as a fluorescent probe to bind with a target DNA adduct (or the reverse transcriptase of the HIV-1 virus), with the fluorescent reaction products being separated by CE and detected by LIF. Aptamers are attractive affinity probes for protein analysis because of high affinity, high specificity, and the potential for a wide range of target proteins. Fluorescence polarization provides unique information for studying molecular interactions. Innovative integrations of these technologies will have broad applications ranging from cancer research, to biomedical diagnosis, to pharmaceutical and environmental analyses.Key words: capillary electrophoresis, laser-induced fluorescence, fluorescence polarization, immunoassay, affinity probes, antibodies, aptamers, DNA damage, toxins, therapeutic drugs.
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Gayton-Ely M, Pappas TJ, Holland LA. Probing affinity via capillary electrophoresis: advances in 2003–2004. Anal Bioanal Chem 2005; 382:570-80. [PMID: 15703915 DOI: 10.1007/s00216-004-3033-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
This review addresses recent advances in capillary electrophoresis of biological-based molecular interaction from a broader perspective, based on applications reported during the period 2003-2004. These capillary electrophoresis-based studies of molecular interactions include affinity capillary electrophoresis, electrokinetic chromatography, and free zone electrophoresis. The review is written as a general synopsis of applications and does not cover the theory or protocol involved in the implementation of the analyses.
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Affiliation(s)
- Melissa Gayton-Ely
- Department of Chemistry, West Virginia University, 217 Clark Hall, P.O.Box 6045, Morgantown, WV 26506, USA
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