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Chatterjee S, Kumari S, Rath S, Priyadarshanee M, Das S. Diversity, structure and regulation of microbial metallothionein: metal resistance and possible applications in sequestration of toxic metals. Metallomics 2020; 12:1637-1655. [PMID: 32996528 DOI: 10.1039/d0mt00140f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Metallothioneins (MTs) are a group of cysteine-rich, universal, low molecular weight proteins distributed widely in almost all major taxonomic groups ranging from tiny microbes to highly organized vertebrates. The primary function of this protein is storage, transportation and binding of metals, which enable microorganisms to detoxify heavy metals. In the microbial world, these peptides were first identified in a cyanobacterium Synechococcus as the SmtA protein which exhibits high affinity towards rising level of zinc and cadmium to preserve metal homeostasis in a cell. In yeast, MTs aid in reserving copper and confer protection against copper toxicity by chelating excess copper ions in a cell. Two MTs, CUP1 and Crs5, originating from Saccharomyces cerevisiae predominantly bind to copper though are capable of binding with zinc and cadmium ions. MT superfamily 7 is found in ciliated protozoa which show high affinity towards copper and cadmium. Several tools and techniques, such as western blot, capillary electrophoresis, inductively coupled plasma, atomic emission spectroscopy and high performance liquid chromatography, have been extensively utilized for the detection and quantification of microbial MTs which are utilized for the efficient remediation and sequestration of heavy metals from a contaminated environment.
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Affiliation(s)
- Shreosi Chatterjee
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela 769 008, Odisha, India.
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Life and death of Trypanosoma cruzi in presence of metals. Biometals 2017; 30:955-974. [PMID: 29081021 DOI: 10.1007/s10534-017-0064-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/26/2017] [Indexed: 12/17/2022]
Abstract
Trypanosoma cruzi has many molecules that need metallic elements to work, allowing cell invasion and the establishment of infection, causing Chagas disease. Nonetheless, knowledge regarding how the parasites address metals and maintain homeostasis is lacking. To study this relationship, zinc, cadmium and mercury were chosen. Epimastigote, trypomastigote and intracellular forms of T. cruzi were incubated with these metals for different times and at different concentrations. In general, epimastigotes were the most sensitive and trypomastigotes the most resistant to metals. ZnCl2 induced low toxic effects to all parasite forms. Although the parasites were very sensitive to the toxic effects of CdCl2 and HgCl2, pretreatment with ZnCl2 decreased the death rate. The trypomastigotes pretreated with CdCl2 were unable to infect the host cells, and the treated intracellular forms were damaged after 2 h of incubation, when the toxic effects were poorly reverted. New insights on metal toxicity mechanisms are provided, helping to understand how metallic ions influence the parasite's biochemical and physiological processes.
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Xiao X, Xue J, Liao L, Chen X, Zeng Y, Wu Y. Determination of trace metallothioneins at nanomolar levels using phenanthroline-copper coordination by fluorescence spectra. ANAL SCI 2015; 30:999-1004. [PMID: 25312631 DOI: 10.2116/analsci.30.999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A direct fluorescence spectra method was applied for the determination of metallothioneins at nanomolar levels. In Britton-Robison (B-R) buffer (pH 7.0), the interaction of bis(1,10-phenanthroline)copper(II) complex cation [Cu(phen)2](2+) and metallothioneins enhanced the fluorescence intensity of system. The fluorescence enhancement at 365 nm was proportional to the concentration of metallothioneins. The mechanism was studied and discussed in terms of the fluorescence and UV-absorption spectra. Under the optimal experimental conditions, at 365 nm, there was a linear relationship between the fluorescence intensity and the concentration of the metallothioneins in the range of 8.30 × 10(-9) - 7.70 × 10(-7) mol L(-1). The linear regression equation was ΔF = 8.96 + 38.01c (mol L(-1)), with a correlation coefficient of r = 0.998 and detection limit 2.50 × 10(-9) mol L(-1). The relative standard deviation was 0.47% (n = 11), and the average recovery 97.2%. The proposed method was successfully reliable, selective and sensitive in determining trace metallothioneins in fish visceral organ samples with the results in good agreement with those obtained by HPLC.
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Affiliation(s)
- Xilin Xiao
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China
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Xiao X, Xue J, Liao L, Huang M, Zhou B, He B. A highly sensitive fluorescence probe for metallothioneins based on tiron-copper complex. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 145:85-89. [PMID: 25767991 DOI: 10.1016/j.saa.2015.02.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 02/07/2015] [Accepted: 02/11/2015] [Indexed: 06/04/2023]
Abstract
The fabrication of tiron-copper complex as a novel fluorescence probe for the sensitive directly detection of metallothioneins at nanomolar levels was demonstrated. In Britton-Robinson (B-R) buffer (pH 7.50), the interaction of bis(tiron)copper(II) complex cation [Cu(tiron)2](2+) and metallothioneins enhanced the fluorescence intensity of the system. The fluorescence enhancement at 347 nm was proportional to the concentration of metallothioneins. The mechanism was studied and discussed in terms of the fluorescence spectra. Under the optimal experimental conditions, at 347 nm, there was a linear relationship between the fluorescence intensity and the concentration of the metallothioneins in the range of 8.80 × 10(-9)-7.70 × 10(-7)mol L(-1), with a correlation coefficient of r=0.995 and detection limit 2.60 × 10(-9)mol L(-1). The relative standard deviation was 0.77% (n=11), and the average recovery 94.4%. The method proposed was successfully reliable, selective and sensitive in determining of trace metallothioneins in fish visceral organ samples with the results in good agreement with those obtained by HPLC.
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Affiliation(s)
- Xilin Xiao
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China.
| | - Jinhua Xue
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China
| | - Lifu Liao
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China
| | - Mingyang Huang
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China
| | - Bin Zhou
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China
| | - Bo He
- College of Chemistry and Chemical Engineering, College of Public Health, Institute of Pathogenic Biology, University of South China, Hengyang City, 421001 Hunan Province, PR China
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Qian QM, Wang YS, Zhou B, Xue JH, Li L, Wang YS, Wang JC, Yin JC, Liu SD, Zhao H, Liu H. Fluorescence quenching determination of metallothioneins using 8-hydroxyquinoline-5-sulphonic acid-Cd(II) chelate. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 118:992-998. [PMID: 24161863 DOI: 10.1016/j.saa.2013.09.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/23/2013] [Accepted: 09/29/2013] [Indexed: 06/02/2023]
Abstract
A novel method for the determination of metallothioneins (MTs) in urine was developed by fluorescence quenching strategy. The response signals linearly correlated with the concentration of MTs in the ranges of 3.12×10(-8)-1.23×10(-6) mol L(-1), and the limit of detection (LOD) was 9.36×10(-9) mol L(-1). The proposed method avoids the label and derivatization steps in common methods, and is reliable, inexpensive and sensitive. Furthermore, the interaction of MTs and 8-hydroxyquinoline-5-sulphonic acid (HQS)-Cd(II) chelate was investigated, and a static quenching mode was proposed to be primarily responsible for the fluorescence quenching event. It could provide a promising potential for the detection of the biomacromolecules which have no native fluorescence, and be benefit to extend the application of fluorescence strategy.
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Affiliation(s)
- Qiu-Mei Qian
- College of Public Health, University of South China, Hengyang 421001, PR China
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Xue JH, Qian QM, Wang YS, Meng XL, Liu L. Resonance light scattering determination of metallothioneins using levofloxacin-palladium complex as a light scattering probe. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 102:205-211. [PMID: 23220658 DOI: 10.1016/j.saa.2012.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 07/02/2012] [Accepted: 10/11/2012] [Indexed: 06/01/2023]
Abstract
A novel method of resonance light scattering (RLS) was developed for the analysis of trace metallothioneins (MTs) in human urine. In a CH(3)COOH-CH(3)COONa buffer solution of pH 4.5, the formation of a complex between levofloxacin (LEV)-Pd and MTs led to enhance the RLS intensity of the system, and the enhanced RLS intensity at 468 nm was proportional to the concentration of MTs in the range of 0.059-22.4 μg mL(-1). The linear regression equation was ΔI=127.5 ρ (μg mL(-1))-88.02 with a correlation coefficient of 0.9992, and the detection limit of 17.8 ng mL(-1). The relative standard deviation and the average recovery were 3.8-5.4% (n=11) and 92.15%, respectively. The proposed method is convenient, reliable and sensitive, and has been used successfully for the determination of trace MTs in human urine samples.
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Affiliation(s)
- Jin-Hua Xue
- College of Public Health, University of South China, Hengyang 421001, PR China
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Qian QM, Wang YS, Yang HX, Xue JH, Liu L, Zhou B, Wang JC, Yin JC, Wang YS. Colorimetric detection of metallothioneins using a thymine-rich oligonucleotide-Hg complex and gold nanoparticles. Anal Biochem 2013; 436:45-52. [PMID: 23357234 DOI: 10.1016/j.ab.2013.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/29/2012] [Accepted: 01/15/2013] [Indexed: 01/14/2023]
Abstract
A simple and sensitive method for label-free, colorimetric detection of metallothioneins (MTs) has been developed by using a thymine (T)-rich oligonucleotide (TRO)-Hg-AuNP system. In this colorimetric strategy, the thiol groups of MTs could interact with mercury from the T-Hg(2+)-T complex to release TRO, resulting in a color change of the system. The response signals linearly correlated with the concentration of MTs over the range of 2.56 × 10(-8) to 3.08 × 10(-7) mol L(-1), and the limit of detection was 7.67 × 10(-9) mol L(-1). The relative standard deviation and the recovery were 2.3-4.8% (n = 11) and 94.2-103.9%, respectively. The proposed method avoids the label and derivatization steps in common methods, allows direct analysis of the samples by the naked eye without costly instruments, and is reliable, inexpensive, and sensitive.
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Affiliation(s)
- Qiu-Mei Qian
- College of Public Health, University of South China, Hengyang 421001, People's Republic of China
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O'Connor KC, Lopez-Amaya C, Gagne D, Lovato L, Moore-Odom NH, Kennedy J, Krupp L, Tenembaum S, Ness J, Belman A, Boyko A, Bykova O, Mah JK, Stoian CA, Waubant E, Kremenchutzky M, Ruggieri M, Bardini MR, Rensel M, Hahn J, Weinstock-Guttman B, Yeh EA, Farrell K, Freedman MS, Iivanainen M, Bhan V, Dilenge M, Hancock MA, Gano D, Fattahie R, Kopel L, Fournier AE, Moscarello M, Banwell B, Bar-Or A. Anti-myelin antibodies modulate clinical expression of childhood multiple sclerosis. J Neuroimmunol 2010; 223:92-9. [PMID: 20381173 DOI: 10.1016/j.jneuroim.2010.02.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 02/02/2010] [Accepted: 02/22/2010] [Indexed: 10/19/2022]
Abstract
Anti-myelin basic protein (MBP) antibodies in pediatric-onset MS and controls were characterized. Serum samples were obtained from 94 children with MS and 106 controls. Paired CSF and serum were obtained from 25 children with MS at time of their initial episode of acute demyelinating syndrome (ADS). Complementary assays were applied across samples to evaluate the presence, and the physical binding properties, of anti-MBP antibodies. While the prevalence and titers of serum anti-MBP antibodies against both immature and mature forms of MBP were similar in children with MS and in controls, binding characteristics and formal Surface Plasmon Resonance (SPR) studies indicated surprisingly high binding affinities of all pediatric anti-MBP antibodies. Serum levels of anti-MBP antibodies correlated significantly with their CSF levels, and their presence in children with MS was associated with significantly increased risk of an acute disseminated encephalomyelitis-like initial clinical presentation. While antibodies to both immature and mature forms of MBP can be present as part of the normal pediatric humoral repertoire, these anti-myelin antibodies are of surprisingly high affinity, can access the CNS during inflammation, and have the capacity to modulate disease expression. Our findings identify an immune mechanism that could contribute to the observed heterogeneity in spectrum of clinical presentations in early-onset MS.
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Affiliation(s)
- K C O'Connor
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Krizkova S, Blahova P, Nakielna J, Fabrik I, Adam V, Eckschlager T, Beklova M, Svobodova Z, Horak V, Kizek R. Comparison of Metallothionein Detection by Using Brdicka Reaction and Enzyme-Linked Immunosorbent Assay Employing Chicken Yolk Antibodies. ELECTROANAL 2009. [DOI: 10.1002/elan.200900243] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Krizkova S, Adam V, Eckschlager T, Kizek R. Using of chicken antibodies for metallothionein detection in human blood serum and cadmium-treated tumour cell lines after dot- and electroblotting. Electrophoresis 2009; 30:3726-35. [DOI: 10.1002/elps.200900201] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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12
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Optimization of time-resolved fluorescence assay for detection of europium-tetraazacyclododecyltetraacetic acid-labeled ligand-receptor interactions. Anal Biochem 2009; 398:15-23. [PMID: 19852924 DOI: 10.1016/j.ab.2009.10.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 10/12/2009] [Accepted: 10/16/2009] [Indexed: 12/27/2022]
Abstract
Lanthanide-based luminescent ligand binding assays are superior to traditional radiolabel assays due to improving sensitivity and affordability in high-throughput screening while eliminating the use of radioactivity. Despite significant progress using lanthanide(III)-coordinated chelators such as diethylenetriaminepentaacetic acid (DTPA) derivatives, dissociation-enhanced lanthanide fluoroimmunoassays (DELFIAs) have not yet been successfully used with more stable chelators (e.g., tetraazacyclododecyltetraacetic acid [DOTA] derivatives) due to the incomplete release of lanthanide(III) ions from the complex. Here a modified and optimized DELFIA procedure incorporating an acid treatment protocol is introduced for use with Eu(III)-DOTA-labeled peptides. Complete release of Eu(III) ions from DOTA-labeled ligands was observed using hydrochloric acid (2.0M) prior to the luminescent enhancement step. [Nle(4),d-Phe(7)]-alpha-melanocyte-stimulating hormone (NDP-alpha-MSH) labeled with Eu(III)-DOTA was synthesized, and the binding affinity to cells overexpressing the human melanocortin-4 (hMC4) receptor was evaluated using the modified protocol. Binding data indicate that the Eu(III)-DOTA-linked peptide bound to these cells with an affinity similar to its DTPA analogue. The modified DELFIA procedure was further used to monitor the binding of an Eu(III)-DOTA-labeled heterobivalent peptide to the cells expressing both hMC4 and cholecystokinin-2 (CCK-2) receptors. The modified assay provides superior results and is appropriate for high-throughput screening of ligand libraries.
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Ligand-binding assays: risk of using a platform supported by a single vendor. Bioanalysis 2009; 1:629-36. [DOI: 10.4155/bio.09.46] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The use of biological reagents in ligand-binding assays (LBAs) presents inherent challenges when measuring the concentration of large molecules in complex matrices. As a result, there are relatively few platforms that provide the accuracy, precision and robustness needed to determine the concentration of macromolecular therapies and biomarkers, and demonstrate the presence or absence of an immune response. Some bioanalytical laboratories use only one LBA platform to reduce costs, increase efficiency and maintain optimal assay performance. However, the business and regulatory risks of using a single platform supported by only one vendor should be considered. This article summarizes the immunological methods used to support bioanalysis for large molecules that are supported by a single vendor, the benefits of being dedicated to a single platform for bioanalysis used for regulatory filings, the costs associated with restructuring if an immunoassay platform is discontinued and recommendations to mitigate risk when using LBAs in drug development. The experience with the recent discontinuation of the BioVeris™ electrochemiluminescent-based platform is discussed.
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Lambracht-Washington D, O'Connor KC, Cameron EM, Jowdry A, Ward ES, Frohman E, Racke MK, Monson NL. Antigen specificity of clonally expanded and receptor edited cerebrospinal fluid B cells from patients with relapsing remitting MS. J Neuroimmunol 2007; 186:164-76. [PMID: 17451814 PMCID: PMC2709235 DOI: 10.1016/j.jneuroim.2007.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 02/20/2007] [Accepted: 03/02/2007] [Indexed: 12/19/2022]
Abstract
We re-engineered the immunoglobulin rearrangements from clonally expanded CSF B cells of three Multiple Sclerosis patients as Fab fragments, and used three methods to test for their antigen (Ag) specificity. Nine out of ten Fab fragments were reactive to Myelin Basic Protein (MBP). The one Fab that did not react to MBP was a product of receptor editing. Two of the nine MBP reactive Fabs were also reactive to GFAP and CNPase, indicating that these clones were polyreactive. Targeting the mechanisms that allow these self-reactive B cells to reside in the CSF of MS patients may prove to be a potent immunotherapeutic strategy.
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O'Connor KC, Appel H, Bregoli L, Call ME, Catz I, Chan JA, Moore NH, Warren KG, Wong SJ, Hafler DA, Wucherpfennig KW. Antibodies from inflamed central nervous system tissue recognize myelin oligodendrocyte glycoprotein. THE JOURNAL OF IMMUNOLOGY 2005; 175:1974-82. [PMID: 16034142 PMCID: PMC4515951 DOI: 10.4049/jimmunol.175.3.1974] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Autoantibodies to myelin oligodendrocyte glycoprotein (MOG) can induce demyelination and oligodendrocyte loss in models of multiple sclerosis (MS). Whether anti-MOG Abs play a similar role in patients with MS or inflammatory CNS diseases by epitope spreading is unclear. We have therefore examined whether autoantibodies that bind properly folded MOG protein are present in the CNS parenchyma of MS patients. IgG was purified from CNS tissue of 14 postmortem cases of MS and 8 control cases, including cases of encephalitis. Binding was assessed using two independent assays, a fluorescence-based solid-phase assay and a solution-phase RIA. MOG autoantibodies were identified in IgG purified from CNS tissue by solid-phase immunoassay in 7 of 14 cases with MS and 1 case of subacute sclerosing panencephalitis, but not in IgG from noninflamed control tissue. This finding was confirmed with a solution-phase RIA, which measures higher affinity autoantibodies. These data demonstrate that autoantibodies recognizing MOG are present in substantially higher concentrations in the CNS parenchyma compared with cerebrospinal fluid and serum in subjects with MS, indicating that local production/accumulation is an important aspect of autoantibody-mediated pathology in demyelinating CNS diseases. Moreover, chronic inflammatory CNS disease may induce autoantibodies by virtue of epitope spreading.
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Affiliation(s)
- Kevin C O'Connor
- Department of Neurology and Center for Neurologic Disease, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Hemmilä I, Laitala V. Progress in Lanthanides as Luminescent Probes. J Fluoresc 2005; 15:529-42. [PMID: 16167211 DOI: 10.1007/s10895-005-2826-6] [Citation(s) in RCA: 333] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Accepted: 03/01/2005] [Indexed: 12/20/2022]
Abstract
Lanthanides have recently found applications in different fields of biomolecular and medical research. Luminescent lanthanide chelates have created interest mainly due to their unique luminescent properties, such as their long Stokes' shift and exceptional decay times allowing efficient temporal discrimination of background interferences in the assays, such as immunoassays. Recently, new organometallic complexes have been developed giving opportunities to novel applications, in heterogeneous and homogeneous immunoassays, DNA hybridization assays, high-throughput screening as well as in imaging. In addition, encapsulating the chelates into suitable matrix in beads enables the use of new members of lanthanides extending the emission wavelength to micrometer range and decays from a few microseconds to milliseconds. As the luminescence is derived from complicated intra-chelate energy transfer, it also gives novel opportunities to exploit these levels in different types of energy transfer based applications. This review gives a short overview of recent development of lanthanide chelate-labels and discusses in more details of energy levels and their exploitation in new assay formats.
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Affiliation(s)
- I Hemmilä
- Perkin Elmer Life and Analytical Sciences, Wallac Oy, P.O. Box 10, FIN-20101, Turku, Finland.
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Handl HL, Gillies RJ. Lanthanide-based luminescent assays for ligand-receptor interactions. Life Sci 2005; 77:361-71. [PMID: 15894006 DOI: 10.1016/j.lfs.2005.01.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Accepted: 01/05/2005] [Indexed: 11/17/2022]
Abstract
The evaluation of receptor ligand interactions is important in the field of drug discovery and development. Currently these interactions are typically measured with cumbersome (low throughput) radiolabels. Higher throughput screens are available such as fluorescent measurements of G-protein coupled receptor-induced Ca2+ increases or fluorescence anisotropy, yet these have limited applicability and/or low signal to noise. Hence, there is a need to develop more widely applicable and more sensitive labels that can be used to monitor ligand-receptor interactions. Lanthanides provide an attractive alternative to the traditional labels used for monitoring ligand-receptor interactions. The incorporation of lanthanide labels into traditional assays used to assess receptor-ligand interactions can make these assays more affordable, less time consuming and amenable to automation. Lanthanides can be coupled to ligands and provide strong luminescent signals that can be detected using time-resolved fluorescence (TRF) methods. This approach takes advantage of the long fluorescence lifetime of the lanthanide and can detect less than one attomole of europium in a multiwell plate sample. This short review provides a basic introduction into lanthanides and TRF and describes some of the recent assays which have utilized lanthanides as labels to assess ligand-receptor interactions.
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Affiliation(s)
- Heather L Handl
- Arizona Cancer Center, P.O. Box 245024, 1515 N. Campbell, Tucson, AZ 85724, USA
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Handl HL, Vagner J, Yamamura HI, Hruby VJ, Gillies RJ. Lanthanide-based time-resolved fluorescence of in cyto ligand-receptor interactions. Anal Biochem 2005; 330:242-50. [PMID: 15203329 DOI: 10.1016/j.ab.2004.04.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Indexed: 11/23/2022]
Abstract
A lanthanide-based assay for ligand-receptor interactions provides an attractive alternative to the traditional radiolabeled determinations in terms of sensitivity, throughput, and biohazards. We designed and tested peptide ligands modified with an Eu-DTPA chelate. These labeled ligands were used in competitive binding assays with results comparable to those obtained using the traditional radiolabeled binding assays. The sensitivity of time-resolved fluorescence is sufficient to detect attomoles of europium, allowing assays in 96-well plates, compared with 30-mm dishes for (125)I binding assays to whole cells. We verified binding of Eu-DTPA-NDP-alpha-MSH to cells overexpressing the human melanocortin-4 receptor. The Eu-labeled ligand bound to these cells with an affinity similar to that of unlabeled NDP-alpha-MSH and was used to optimize a competitive binding assay. The lanthanide-based assays provided superior results with higher throughput and eliminated the need for radioactive waste disposal. This assay is appropriate for high-throughput screening of ligand libraries.
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Affiliation(s)
- Heather L Handl
- Department of Biochemistry and Molecular Biophysics, University of Arizona, and Arizona Cancer Center, Tucson, AZ 85724, USA
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Su JL, Fornwald J, Rivers P, Goldsworthy S, Looney NA, Hanvey J, Plumpton C, Parham J, Romanos M, Kost TA, Kull FC. A cell-based time-resolved fluorescence assay for selection of antibody reagents for G protein-coupled receptor immunohistochemistry. J Immunol Methods 2004; 291:123-35. [PMID: 15345311 DOI: 10.1016/j.jim.2004.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 04/16/2004] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
A cell-based time-resolved fluorescence (celTRF) immunoassay is described for pre-screening antibodies to G protein-coupled receptor (GPCR) peptides that predicts suitability for immunohistochemistry (IHC). Rat GPCRs were expressed in Saos-2 human osteosarcoma cells via recombinant baculoviruses designed for mammalian cell expression, i.e., the transduced cells were used as a "screening lawn". The lawn was fixed and permeabilized similarly to IHC tissue. The celTRF, a dissociation-enhanced lanthanide fluorescence immunoassay (DELFIA), employed Eu-labelled goat anti-rabbit IgG. It exhibited a broad dynamic range upon which enzyme-linked immunosorbant assay (ELISA)-positive affinity-purified anti-peptide antibody reagents were examined for specificity and potency. Over 150 anti-peptide reagents to 27 GPCRs were characterized. All celTRF-positive antibodies were found to be suitable for IHC, whereas ELISA alone did not predict IHC utility. Examples are illustrated with five rabbit anti-neuropeptide FF receptor 1 (NPFF1) antibodies, where a strong correlation between celTRF potency and IHC utility was observed in both applications. In contrast, two high anti-peptide ELISA titer but celTRF-negative antibodies failed to recognize the NPFF1 receptor in IHC. The celTRF assay was performed manually and in an automated fashion, in our case, using a Biomek FX station and Sami scheduling software. The celTRF is the first in vitro automated assay that offers confident pre-selection of antibodies for IHC and the versatility to accommodate the rapid screening of large numbers of GPCRs. The celTRF is readily applicable to other protein target classes.
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Affiliation(s)
- Jui-Lan Su
- Department of Gene Expression and Protein Biochemistry, GlaxoSmithKline Research and Development, Five Moore Drive, Research Triangle Park, NC 27709, USA.
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A novel substrate for in situ synthesis of oligonucleotide: plasma-treated polypropylene microporous membrane. Colloids Surf A Physicochem Eng Asp 2004. [DOI: 10.1016/j.colsurfa.2004.04.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Butcher HL, Kennette WA, Collins O, Zalups RK, Koropatnick J. Metallothionein mediates the level and activity of nuclear factor kappa B in murine fibroblasts. J Pharmacol Exp Ther 2004; 310:589-98. [PMID: 15039454 DOI: 10.1124/jpet.104.066126] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The zinc-binding protein metallothionein (MT) is associated with resistance to apoptosis. We examined whether MT regulates the zinc-dependent antiapoptotic transcription factor nuclear factor KappaB (NF-KappaB), which is up-regulated under many conditions that lead to elevated MT expression. NF-KappaB protein levels and NF-KappaB-dependent reporter gene activity were examined in clonal MT(+) (MT-WT) and MT(-) (MT-KO) fibroblastic cell lines. The amount of cellular NF-KappaB p65 protein in MT-KO was less than 20% of the amount in MT-WT cells, in accord with increased sensitivity of MT-KO cells to apoptosis. NF-KappaB p65 mRNA levels, and NF-KappaB p50 subunit and IKappaBalpha protein levels, were unchanged. NF-KappaB activity assessed by expression of a transfected NF-KappaB reporter construct was less than half that observed in MT-KO cells. Decreased nuclear localization of NF-KappaB p65 in MT-KO clones was not responsible for differences in activity. In fact, MT-KO cells had higher nuclear levels of NF-KappaB p65 than did MT-WT cells, despite a lower cellular NF-KappaB level and function, suggesting that metallothionein mediated the specific activity of NF-KappaB. Reconstitution of MT by stable incorporation of an MT-1 expression vector in MT-KO cells resulted in increased NF-KappaB p65 (but not IKappaBalpha or NF-KappaB p50), increased NF-KappaB-dependent reporter activity, and increased resistance to apoptosis. These data support the hypothesis that metallothionein positively regulates the cellular level and activity of NF-KappaB.
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Affiliation(s)
- Heather L Butcher
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
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Krogh-Meibom T, Holmskov U, Løvendahl P, Nielsen NI, Ingvartsen KL. A time-resolved immunofluorometric assay for quantification of the bovine collectin conglutinin. J Immunol Methods 2004; 286:87-96. [PMID: 15087224 DOI: 10.1016/j.jim.2003.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Revised: 11/21/2003] [Accepted: 12/01/2003] [Indexed: 11/16/2022]
Abstract
A high capacity time-resolved immunofluorometric assay (TRIFMA) for the bovine collectin conglutinin was developed. The TRIFMA was constructed as a non-competitive sandwich assay based on polyclonal antibodies as the capture reagent and a novel monoclonal antibody raised against conglutinin as the detection reagent and was set up to run on an automatic analyzer designed for the TRIFMA detection system. Polyclonal antibodies immobilized on microtiter plate wells were incubated overnight at 4 degrees C with diluted plasma samples, including quality controls (QC) and dilutions of a plasma with known conglutinin concentration. Conglutinin was sandwiched between the capture antibodies and the monoclonal antibody and the detection optimised with biotin-labelled secondary antibodies and streptavidin-Eu(3+). Plates were washed four times between each step and finally incubated with enhancement solution before measuring the fluorescence. The assay detection limit was 0.34 ng/ml and the working range 0.80 ng/ml-0.20 microg/ml. Intra-plate and inter-plate coefficients of variation (CV) were in the range of 5.0-8.3% and 6.2-7.2%, respectively, at concentrations of 3.4 and 150 ng/ml. Recovery was 90.9+/-2.4% and 98.8+/-2.5% when samples were spiked with 20 ng/ml and 100 ng/ml purified bovine conglutinin (BK). No circadian rhythm (24-h variation) in conglutinin plasma levels was observed across animals, indicating that the plasma levels were not influenced by, e.g. feeding. Samples could be stored at -20 degrees Celsius and were not sensitive to repeated freezing and thawing. In conclusion, the developed TRIFMA for bovine conglutinin is specific and reliable over a measurement range covering most situations.
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Affiliation(s)
- T Krogh-Meibom
- Department of Animal Health and Welfare, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark
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Kobayashi SD, Voyich JM, Braughton KR, Whitney AR, Nauseef WM, Malech HL, DeLeo FR. Gene Expression Profiling Provides Insight into the Pathophysiology of Chronic Granulomatous Disease. THE JOURNAL OF IMMUNOLOGY 2003; 172:636-43. [PMID: 14688376 DOI: 10.4049/jimmunol.172.1.636] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human polymorphonuclear leukocytes (PMNs or neutrophils) kill invading microorganisms with reactive oxygen species (ROS) and cytotoxic granule components. PMNs from individuals with X-linked chronic granulomatous disease (XCGD) do not produce ROS, thereby rendering these individuals more susceptible to infection. In addition, XCGD patients develop tissue granulomas that obstruct vital organs, the mechanism(s) for which are unknown. To gain insight into the molecular processes that contribute to the pathophysiology of XCGD, including formation of granulomas, we compared global gene expression in PMNs from XCGD patients and healthy control individuals. Genes encoding mediators of inflammation and host defense, including CD11c, CD14, CD54, FcgammaR1, FcalphaR, CD120b, TLR5, IL-4R, CCR1, p47(phox), p40(phox), IL-8, CXCL1, Nramp1, and calgranulins A and B, were up-regulated constitutively in unstimulated XCGD patient PMNs. By comparing transcript levels in normal and XCGD PMNs after phagocytosis, we discovered 206 genes whose expression changed in the presence and the absence of ROS, respectively. Notably, altered Bcl2-associated X protein synthesis accompanied defective neutrophil apoptosis in XCGD patients. We hypothesize that granuloma formation in XCGD patients reflects both increased proinflammatory activity and defective PMN apoptosis, and we conclude that ROS contribute directly or indirectly to the resolution of the inflammatory response by influencing PMN gene transcription.
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Affiliation(s)
- Scott D Kobayashi
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
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