1
|
Féau C, Klein E, Dosche C, Kerth P, Lebeau L. Synthesis and characterization of coumarin-based europium complexes and luminescence measurements in aqueous media. Org Biomol Chem 2009; 7:5259-70. [PMID: 20024123 DOI: 10.1039/b907579h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of new ligands suitable for the formation of luminescent lanthanide complexes in water is described. The chelates are designed for analyte labeling and play the role of fluorescent donor in homogeneous time-resolved fluorescence assays using LEDs as a light source for excitation at 370 nm. Ligands are constructed from a coumarin nucleus, for lanthanide sensitization, and different aminomethylenecarboxy moieties are introduced in positions 7 and 5, 6, or 8 of the sensitizer. A reactive spacer arm under biocompatible conditions (maleimide, azide) is introduced at position 3 for ultimate bioconjugation purposes. The synthesis and characterization of the ligands are described, together with the preparation of their corresponding europium complexes. Photophysical properties of the complexes are investigated in water by means of UV-vis and luminescence spectroscopy.
Collapse
Affiliation(s)
- Clémentine Féau
- Laboratoire de Chimie Organique Appliquée, C.A.M.B., UMR 7199 CNRS-UdS, Faculté de Pharmacie, 74 route du Rhin-BP 60024, 67401, Illkirch Cedex, France
| | | | | | | | | |
Collapse
|
2
|
Hemmilá I, Mukkala VM. Time-Resolution in Fluorometry Technologies, Labels, and Applications in Bioanalytical Assays. Crit Rev Clin Lab Sci 2008. [DOI: 10.1080/20014091084254] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
3
|
Hervé B, André R, Robert T. Phosphoramidite Reagents for the Easy Preparation of Polylabelled Oligonucleotide Probes. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/07328319108046480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Bazin Hervé
- a CIS bioindustries; Département de Recherche Fondamentale/Laboratoires de chimie, Centre d'Etudes Nucléaires de Grenoble 85 X , F-38041 , GRENOBLE Cédex , France
| | - Roget André
- a CIS bioindustries; Département de Recherche Fondamentale/Laboratoires de chimie, Centre d'Etudes Nucléaires de Grenoble 85 X , F-38041 , GRENOBLE Cédex , France
| | - Téoule Robert
- a CIS bioindustries; Département de Recherche Fondamentale/Laboratoires de chimie, Centre d'Etudes Nucléaires de Grenoble 85 X , F-38041 , GRENOBLE Cédex , France
| |
Collapse
|
4
|
Nilsson M, Banér J, Mendel-Hartvig M, Dahl F, Antson DO, Gullberg M, Landegren U. Making ends meet in genetic analysis using padlock probes. Hum Mutat 2002; 19:410-5. [PMID: 11933195 DOI: 10.1002/humu.10073] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Padlock probes are molecular tools that combine highly specific target sequence recognition with the potential for multiplexed analysis of large sets of target DNA or RNA sequences. In this brief review, we exemplify the ability of these probes to distinguish single-nucleotide target sequence variants. We further discuss means to detect the location of target sequences in situ, and to amplify reacted padlock probes via rolling-circle replication, as well as to sort reaction products on tag-arrays. We argue that the probes have the potential to render high-throughput genetic analyses precise and affordable.
Collapse
Affiliation(s)
- Mats Nilsson
- Beijer Laboratory, Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala, Sweden
| | | | | | | | | | | | | |
Collapse
|
5
|
Ylikoski A, Karp M, Pettersson K, Lilja H, Lövgren T. Simultaneous quantification of human glandular kallikrein 2 and prostate-specific antigen mRNAs in peripheral blood from prostate cancer patients. J Mol Diagn 2001; 3:111-22. [PMID: 11486050 PMCID: PMC1906957 DOI: 10.1016/s1525-1578(10)60660-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We present a multiplexed and internally calibrated quantitative reverse transcription-PCR (QRT-PCR) assay to detect human glandular kallikrein 2 (hK2) and prostate-specific antigen (PSA) transcripts in blood samples from healthy subjects and prostate cancer (PC) patients. The assay detected 50 copies of hK2 and PSA mRNA, and 1 PSA- and 10 hK2-expressing LNCaP cells in the presence of 2.5 x 10(6) PSA- and hK2-negative cells. In PC patients, 20 of 25 and 19 of 25 gave detectable PSA and hK2 mRNAs, respectively. Number of hK2 mRNA copies was significantly higher than that of PSA mRNA copies in patients with biochemically progressive (P = 0.02) PC, and with locally advanced and metastasized (P = 0.004) PC. Patients with rapidly progressive and hormone refractory PC gave detectable hK2 mRNA only in 2 of 8 and PSA mRNA in 3 of 8 patients. Neither PSA nor hK2 mRNAs were detected in 16 healthy subjects. PSA and hK2 discriminated PC patients with biochemically progressive and advanced disease from the controls and from the aggressive distant metastatic disease. The assay provides a reliable quantification of the number of hK2 and PSA mRNA copies, allows to discriminate PC cases from healthy subjects, and offers a tool for further studies on molecular staging of PC.
Collapse
Affiliation(s)
- A Ylikoski
- Department of Biotechnology, University of Turku, Turku, Finland
| | | | | | | | | |
Collapse
|
6
|
Sjöroos M, Ilonen J, Lövgren T. Solid-Phase PCR with Hybridization and Time-resolved Fluorometry for Detection of HLA-B27. Clin Chem 2001. [DOI: 10.1093/clinchem/47.3.498] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Background: Preactivated solid surfaces provide new possibilities for multiple consecutive reactions in a microtiter plate format. In this study, a combination of PCR and subsequent hybridization in the same microtiter well was applied for the detection of HLA-B27 alleles.
Methods: A multiplex solid-phase PCR to amplify the HLA-B27 alleles together with β-actin as an amplification control gene was performed on the NucleoLinkTM (Nunc) surface. PCR was followed by hybridization and detection with time-resolved fluorescence. For the covalent capture of the PCR primers onto the solid support via a 1-(3-dimethylamino-propyl)-3-ethylcarbodiimide hydrochloride-mediated reaction, different 5′-end modifications of oligonucleotides were tested [amination, phosphorylation, and a poly(dT)10 linker].
Results: For covalent immobilization of the primers, amination of the 5′ end combined with use of the poly(dT)10 linker was superior. At least 19.5% of the primer added per well was attached via a stable bond. When the standard time-resolved, fluorescence-based HLA-B27 detection system was compared with the newly developed method in a sample series of 82 genomic DNAs and the corresponding dried-blood spots, all results were in full agreement.
Conclusions: The new solid-phase PCR approach can be applied for multiple-target DNA detection. PCR followed by hybridization can be accomplished in a few hours using precoated strips and dried-blood spot PCR templates.
Collapse
Affiliation(s)
- Minna Sjöroos
- JDF Center for Prevention of Type 1 Diabetes in Finland, and Departments of
- Virology and
| | - Jorma Ilonen
- JDF Center for Prevention of Type 1 Diabetes in Finland, and Departments of
- Virology and
| | | |
Collapse
|
7
|
Nilsson M, Barbany G, Antson DO, Gertow K, Landegren U. Enhanced detection and distinction of RNA by enzymatic probe ligation. Nat Biotechnol 2000; 18:791-3. [PMID: 10888852 DOI: 10.1038/77367] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is important that RNA molecules representing members of gene families are distinguished in expression analyses, and even greater resolving power may be required to identify allelic variants of transcripts in order to investigate imprinting or to study the distribution of mutant genes in tissues. Ligase-mediated gene detection allows precise distinction of DNA sequence variants, but it is not known if ligases can also be used to distinguish variants of RNA sequences. Here we present conditions for efficient ligation of pairs of DNA oligonucleotides hybridizing next to one another on RNA strands, permitting discrimination of any single nucleotide probe-target mismatch by a factor of between 20- and 200-fold. The mechanism allows padlock probes to be used to distinguish single-nucleotide variants in RNA. Ligase-mediated gene detection could therefore provide highly sensitive and accurate ligase-mediated detection and distinction of RNA sequence variants in solution, on DNA microarrays, and in situ.
Collapse
Affiliation(s)
- M Nilsson
- Department of Molecular Cell Biology, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
| | | | | | | | | |
Collapse
|
8
|
Yamamoto K, Serizawa T, Muraoka Y, Akashi M. Synthesis and functionalities of poly(N-vinylalkylamide). XII. Synthesis and thermosensitive property of poly(vinylamine) copolymer prepared from poly(N-vinylformamide-co-N-vinylisobutyramide). ACTA ACUST UNITED AC 2000. [DOI: 10.1002/1099-0518(20001001)38:19<3674::aid-pola210>3.0.co;2-n] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
9
|
Ylikoski A, Sjöroos M, Lundwall A, Karp M, Lövgren T, Lilja H, Iitiä A. Quantitative Reverse Transcription-PCR Assay with an Internal Standard for the Detection of Prostate-specific Antigen mRNA. Clin Chem 1999. [DOI: 10.1093/clinchem/45.9.1397] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Background: Circulating prostate cells can be detected with a reverse transcription-PCR (RT-PCR) assay for prostate-specific antigen (PSA) mRNA. We have developed a new quantitative RT-PCR method for measuring PSA mRNA.
Methods: The method uses a PSA-like internal standard (IS) mRNA that is added into the sample at the beginning of the RNA extraction and coamplified by RT-PCR with the PSA in the sample. After PCR amplification, the IS and PSA products are selectively detected by hybridization in a microtitration plate using probes labeled with fluorescent europium chelates.
Results: The method was validated with PSA and IS mRNAs and PSA-expressing cells to obtain a detection limit of 50 PSA mRNA copies (i.e., signal 2 times the mean of zero signal), linearity up to 106 copies, and detection of a single PSA-expressing cell. In preliminary evaluations, 60% (n = 10) of the prostate cancer patients with skeletal metastases gave results above the detection limit (500 PSA mRNA copies in 5 mL of blood). The total number of PSA copies ranged from 900 ± 200 to 44 100 ± 4900 (mean ± SD) in the samples, corresponding to ∼1–100 PSA-expressing cells in 5 mL of blood. In the controls (n = 34), none of the healthy females and 2 of 19 healthy males had detectable PSA mRNA [700 ± 100 and 2000 ± 900 (mean ± SD) PSA mRNA copies in 5 mL of blood for the 2 males].
Conclusions: The assay provides sensitive and quantitative detection of PSA mRNA expression from blood samples and can be used to establish the clinically significant number of PSA mRNA copies in prostate cancer.
Collapse
Affiliation(s)
- Alice Ylikoski
- Department of Biotechnology, University of Turku, Tykistökatu 6 A, 6th Floor, FIN-20520 Turku, Finland
| | - Minna Sjöroos
- Department of Biotechnology, University of Turku, Tykistökatu 6 A, 6th Floor, FIN-20520 Turku, Finland
| | - Åke Lundwall
- Department of Clinical Chemistry, Lund University, University Hospital, S-20502 Malmö, Sweden
| | - Matti Karp
- Department of Biotechnology, University of Turku, Tykistökatu 6 A, 6th Floor, FIN-20520 Turku, Finland
| | - Timo Lövgren
- Department of Biotechnology, University of Turku, Tykistökatu 6 A, 6th Floor, FIN-20520 Turku, Finland
| | - Hans Lilja
- Department of Clinical Chemistry, Lund University, University Hospital, S-20502 Malmö, Sweden
| | - Antti Iitiä
- InnoTrac Diagnostics Oy, Tykistökatu 6 A, 7th Floor, FIN-20520 Turku, Finland
| |
Collapse
|
10
|
Jiang M, Aittomäki K, Nilsson C, Pakarinen P, Iitiä A, Torresani T, Simonsen H, Goh V, Pettersson K, de la Chapelle A, Huhtaniemi I. The frequency of an inactivating point mutation (566C-->T) of the human follicle-stimulating hormone receptor gene in four populations using allele-specific hybridization and time-resolved fluorometry. J Clin Endocrinol Metab 1998; 83:4338-43. [PMID: 9851774 DOI: 10.1210/jcem.83.12.5306] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have described previously in the Finnish population an inactivating point mutation (566C-->T) in the human FSH receptor (FSHR) gene. In women, this mutation causes hypergonadotropic ovarian failure with arrest of follicular maturation and infertility, whereas in men, there is variable suppression of spermatogenesis, but no absolute infertility. To determine whether the same FSHR mutation occurs in other populations, its frequency was determined in Finland, Switzerland, Denmark, and the Chinese population of Singapore. The mutation was screened for using genomic DNA extracted from whole blood or dried blood spots. Exon 7 of the FSHR gene was first amplified using a pair of biotinylated primers. The PCR products were then immobilized on streptavidin-coated microtitration wells and hybridized using short allele-specific oligonucleotide probes labeled with europium. Time-resolved fluorometry was used for europium signal detection. To test the reliability of this method, 40 isolated DNA samples and 35 dried blood spot samples were blindly tested for the 566C-->T FSHR mutation. The analyses yielded identical results with denaturing gradient gel electrophoresis and allele-specific restriction enzyme digestion of the same samples, thus demonstrating the reliability of the tested method. Automation of this procedure allows the screening of large numbers of samples, which was subsequently carried out to investigate the frequency of the 566C-->T mutation in the study populations. A total of 4981 samples from the above-mentioned 4 countries were analyzed. The frequency of the 566C-->T mutation was 0.96% for all Finnish samples (n=1976), with a strong enrichment of the mutant allele in the northeastern part of the country. Only 1 mutation carrier was identified in the samples from Switzerland (n=1162), whereas none was found in samples from Denmark (n=1094) and the Singapore Chinese (n=540). These results suggest that the 566C-->T mutation of the FSHR gene is enriched in Finland, but is uncommon in other populations.
Collapse
Affiliation(s)
- M Jiang
- Department of Physiology, University of Turku, Finland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Nilsson C, Jiang M, Pettersson K, Iitiä A, Mäkelä M, Simonsen H, Easteal S, Herrera RJ, Huhtaniemi I. Determination of a common genetic variant of luteinizing hormone using DNA hybridization and immunoassays. Clin Endocrinol (Oxf) 1998; 49:369-76. [PMID: 9861329 DOI: 10.1046/j.1365-2265.1998.00532.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE An immunologically anomalous form of LH, due to two point mutations in codons 8 and 15 of the LH beta gene, has previously been described. LH status, i.e. the discrimination between wild-type (WT) and variant (V) LH, is usually determined by immunoassays, which can be unreliable at low serum concentrations of LH. A DNA hybridization assay was therefore developed to score the LH genotype in all subjects, independent of their serum LH concentrations. To evaluate the performance of the hybridization method, and to expand our observations of the worldwide occurrence of the V-LH, we determined its frequency in additional populations. To confirm the connection between the anomalous immunoreactivity and the V-LH beta gene, we also sequenced the LH beta subunit gene of a homozygous person. DESIGN According to the ratio of two immunoassays, one detecting only WT-LH and the other detecting equally WT and V-LH, individuals can be classified as homozygotes for the V-LH beta allele, heterozygotes or WT. DNA samples from persons with known LH status, according to the immunoassays, were used for the development and evaluation of a new allele-specific DNA hybridization assay. This assay, and PCR and restriction fragment length polymorphism analysis, were used to determine the frequency of the V-LH beta allele in DNA samples obtained from eight populations. PATIENTS Ambulatory adult men and women, apparently healthy and with no endocrine disorders. RESULTS The LH genotyping by immunoassays and by the new hybridization method gave identical results with all samples analysed (n = 25). The V-LH beta subunit was observed to always have the two point mutations, and to be identical with the ones previously reported. The V-LH beta carrier frequency in the DNA samples collected from various populations varied between 0 and 53.5%. CONCLUSIONS The immunoassay technique and the hybridization assay can be used as alternatives to determine the LH status. A great variation in carrier frequency of the V-LH beta allele is observed in different populations.
Collapse
Affiliation(s)
- C Nilsson
- Department of Biotechnology, University of Turku
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Luyten I, Herdewijn P. Hybridization properties of base-modified oligonucleotides within the double and triple helix motif. Eur J Med Chem 1998. [DOI: 10.1016/s0223-5234(98)80016-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
13
|
Nilsson M, Krejci K, Koch J, Kwiatkowski M, Gustavsson P, Landegren U. Padlock probes reveal single-nucleotide differences, parent of origin and in situ distribution of centromeric sequences in human chromosomes 13 and 21. Nat Genet 1997; 16:252-5. [PMID: 9207789 DOI: 10.1038/ng0797-252] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chromosome centromeres, composed of repeated DNA sequences, orchestrate the correct segregation of chromatids in cell division. We have examined the centromeres of human chromosomes 13 and 21 by studying the distribution, in situ, of two alpha satellite sequences that differ in a single nucleotide position. This was possible using padlock probes, oligo-nucleotides that can be ligated into circles upon target recognition. The segregation of individual 13 and 21 homologues in a family was followed by monitoring of the signals from two differentially labelled probes, specific for either sequence variant. A characteristic arrangement of the repeat motifs in three separate spots, oriented transverse to the length axis of the metaphase chromosomes and bilaterally symmetric, indicates that only parts of the detected regions are involved in the centromeric region, joining the sister chromatids before anaphase.
Collapse
Affiliation(s)
- M Nilsson
- Beijer Laboratory, Department of Medical Genetics, Uppsala, Sweden.
| | | | | | | | | | | |
Collapse
|
14
|
Heinonen P, Iitiä A, Torresani T, Lövgren T. Simple triple-label detection of seven cystic fibrosis mutations by time-resolved fluorometry. Clin Chem 1997. [DOI: 10.1093/clinchem/43.7.1142] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
We describe a simple hybridization assay performed in microtitration wells with use of DNA probes labeled with three different lanthanide chelates for detection of seven mutations that cause cystic fibrosis. The assay is based on DNA amplification of four fragments containing the mutations (ΔF508, G1717→A, G542X, R553X, 3905 insertion T, W1282X, and N1303K) by PCR, followed by hybridization with short, allele-specific oligonucleotide probes labeled with europium, terbium, or samarium chelates. Because the technology makes it possible to hybridize three DNA probes simultaneously in one reaction, all 14 mutation-related alleles were detected in a total of five reaction wells. Blood spot specimens, obtained from children with cystic fibrosis, their parents, and their siblings, have been assayed, and for all the probes the positive signal-to-noise ratios are >10. Solution hybridization utilizing triple-label time-resolved fluorometry combined with PCR is a suitable procedure for large-scale screening and automation.
Collapse
Affiliation(s)
- Pia Heinonen
- Department of Biotechnology, University of Turku, FIN-20520 Turku, Finland
| | - Antti Iitiä
- Department of Biotechnology, University of Turku, FIN-20520 Turku, Finland
- Current address: InnoTrac Diagnostics Oy, FIN-20520 Turku, Finland
| | - Toni Torresani
- Division of Endocrinology, University Children’s Hospital, CH-8032 Zürich, Switzerland
| | - Timo Lövgren
- Department of Biotechnology, University of Turku, FIN-20520 Turku, Finland
| |
Collapse
|
15
|
Nilsson C, Pettersson K, Millar RP, Coerver KA, Matzuk MM, Huhtaniemi IT. Worldwide frequency of a common genetic variant of luteinizing hormone: an international collaborative research. International Collaborative Research Group. Fertil Steril 1997; 67:998-1004. [PMID: 9176435 DOI: 10.1016/s0015-0282(97)81430-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To determine the worldwide frequency of a common immunological LH variant because of two point mutations in the LH beta-subunit gene (Trp8Arg and Ile15Thr). DESIGN Cross-sectional study on LH status (variant and wild-type) in serum (or DNA) samples from Finland (Finns and Lapps), Estonia, Poland, Sweden, The Netherlands, United Kingdom, Italy, South Africa (blacks), Thailand, China, Japan, and the United States (Hispanics and blacks). SETTING Academic research environment. PATIENT(S) Ambulatory adult men and women (n = 2,936) with minor illnesses and no known endocrinological disorders. INTERVENTION A single blood sample was collected from each subject. MAIN OUTCOME MEASURE(S) The LH status was determined by two immunofluorometric assays using monoclonal antibodies. One (assay 1) only recognizes the wild-type LH, the other (assay 2) recognizes equally variant and wild-type LH. The ratio of assay 1 to assay 2 indicates the LH status: wild-type, > 0.9; heterozygote, 0.2 to 0.9; and homozygote, < 0.15. One population (Lapps) was studied by DNA analysis using polymerase chain reaction and allele-specific oligonucleotide hybridization. RESULT(S) The carrier frequency of the variant LH beta allele varied from 7.1% in U.S. Hispanics to 41.9% in Lapps of northern Finland. The variant LH beta allele tended to be more common in populations from Northern Europe as compared with those from Asia. CONCLUSION(S) The high frequency of the LH beta variant worldwide makes it an important confounding factor when obtaining disproportionately low LH levels with some immunometric assays. The LH variant may contribute to some pathologies of the pituitary-gonadal function.
Collapse
Affiliation(s)
- C Nilsson
- Department of Biotechnology, University of Turku, Finland
| | | | | | | | | | | |
Collapse
|
16
|
Korshun VA, Pestov NB, Nozhevnikova EV, Prokhorenko IA, Gontarev SV, Berlin YA. Reagents for Multiple Non-Radioactive Labelling of Oligonucleotides. SYNTHETIC COMMUN 1996. [DOI: 10.1080/00397919608004566] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
17
|
Erout MN, Elaíssari A, Pichot C, Cros P, Kurfürst R. Characterization of the Grafting Reaction Between Oligodeoxyribonucleotides and N-Vinyl Pyrrolidone /N-Acryloxy Succinimide Copolymers by Size Exclusion Chromatography and Free Solution Capillary Electrophoresis. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 1996. [DOI: 10.1080/10236669608233914] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
18
|
Dickson EF, Pollak A, Diamandis EP. Ultrasensitive bioanalytical assays using time-resolved fluorescence detection. Pharmacol Ther 1995; 66:207-35. [PMID: 7667396 DOI: 10.1016/0163-7258(94)00078-h] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This article reviews the use of time-resolved fluorimetric detection of lanthanide chelate luminescence as a detection method for ultrasensitive bioanalytical assays. Assay formats and detection methods, and the principle of time-resolved fluorimetric detection, are described. Detection systems, assay formats, reagents, and instrumentation for time-resolved fluorimetric detection are outlined. A review of published and commercially available immunoassays and DNA hybridization assays using time-resolved fluorimetric detection of lanthanide chelate luminescence is given.
Collapse
Affiliation(s)
- E F Dickson
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario
| | | | | |
Collapse
|
19
|
Halonen P, Rocha E, Hierholzer J, Holloway B, Hyypiä T, Hurskainen P, Pallansch M. Detection of enteroviruses and rhinoviruses in clinical specimens by PCR and liquid-phase hybridization. J Clin Microbiol 1995; 33:648-53. [PMID: 7751371 PMCID: PMC228007 DOI: 10.1128/jcm.33.3.648-653.1995] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A sensitive method based on PCR followed by liquid-phase hybridization for detection of enterovirus and rhinovirus RNAs in clinical specimens and cell culture supernatants is described. RNA was extracted from stool samples, throat swabs, nasopharyngeal aspirates, cerebrospinal fluid, urine, and plasma with a commercial phenol-guanidinium-chloroform reagent and purified on a polysulfone membrane, on which the reverse transcriptase reaction was also done. Two sets of oligonucleotide primers from the 5' noncoding region of picornaviruses were selected for DNA amplification of 153-bp (enterovirus) and 120-bp (rhinovirus) regions. Double-stranded amplicons were digested into single strands with T7 gene 6 exonuclease and quantitated by an assay using a europium-labeled probe, streptavidin- and biotinylated probe-coated microtitration wells, and time-resolved fluorometry. The sensitivity of the assay was about one template molecule when purified coxsackievirus A9 RNA was used. All enterovirus prototype strains, except echoviruses 22 and 23, and clinical isolates grown in cell culture or suckling mice were strongly positive by the enterovirus PCR-hybridization, as were selected prototype strains and untyped isolates of rhinoviruses by the rhinovirus PCR-hybridization. In a series of 100 clinical specimens tested, the results for 92 agreed with virus culture results. The detection method described will be useful in etiopathogenic studies on enteroviruses and rhinoviruses.
Collapse
Affiliation(s)
- P Halonen
- Respiratory and Enteric Viruses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Dickson EF, Pollak A, Diamandis EP. Time-resolved detection of lanthanide luminescence for ultrasensitive bioanalytical assays. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1995; 27:3-19. [PMID: 7699520 DOI: 10.1016/1011-1344(94)07086-4] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The principles and practice of the application of time-resolved lanthanide chelate luminescence (or fluorescence) as a detection method for ultrasensitive bioanalytical assays such as immunoassays and nucleic acid hybridization assays are reviewed. The various lanthanide chelate-based detection systems which have been developed for use in heterogeneous and homogeneous assay formats are described, including reagents, assay methods, and instrumentation, along with recent improvements in these methods. Detection systems described include those based on dissociative enhancement of lanthanide ions, direct labeling with luminescent chelates, enzyme-amplified lanthanide luminescence, lanthanide luminescence quenching, and energy transfer.
Collapse
Affiliation(s)
- E F Dickson
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario
| | | | | |
Collapse
|
21
|
Nilsson M, Malmgren H, Samiotaki M, Kwiatkowski M, Chowdhary BP, Landegren U. Padlock probes: circularizing oligonucleotides for localized DNA detection. Science 1994; 265:2085-8. [PMID: 7522346 DOI: 10.1126/science.7522346] [Citation(s) in RCA: 507] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nucleotide sequence information derived from DNA segments of the human and other genomes is accumulating rapidly. However, it frequently proves difficult to use such short DNA segments to identify clones in genomic libraries or fragments in blots of the whole genome or for in situ analysis of chromosomes. Oligonucleotide probes, consisting of two target-complementary segments, connected by a linker sequence, were designed. Upon recognition of the specific nucleic acid molecule the ends of the probes were joined through the action of a ligase, creating circular DNA molecules catenated to the target sequence. These probes thus provide highly specific detection with minimal background.
Collapse
Affiliation(s)
- M Nilsson
- Beijer Laboratory, Department of Medical Genetics, Biomedical Center, Uppsala, Sweden
| | | | | | | | | | | |
Collapse
|
22
|
Eggertsen G, Eriksson M, Wiklund O, Iitiä A, Olofsson SO, Angelin B, Berglund L. Time-resolved fluorometry in the genetic diagnosis of familial defective apolipoprotein B-100. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)40092-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
23
|
Huoponen K, Juvonen V, Iitiä A, Dahlen P, Siitari H, Aula P, Nikoskelainen E, Savontaus ML. Time-resolved fluorometry in the diagnosis of Leber hereditary optic neuroretinopathy. Hum Mutat 1994; 3:29-36. [PMID: 8118464 DOI: 10.1002/humu.1380030106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have applied time-resolved fluorometry (TRF) to construct a DNA hybridization assay for the diagnosis of Leber hereditary optic neuroretinopathy (LHON). A rapid and reliable detection of the most prevalent mitochondrial DNA (mtDNA) point mutation associated with LHON is demonstrated. In addition, the TRF-method can be used in the quantification of heteroplasmy, a phenomenon commonly present in mtDNA mutations. The assay includes PCR amplification of a fragment encompassing the mutation site followed by hybridization reactions with allele-specific europium (Eu)-labelled oligonucleotide probes. A time-resolved fluorometer is used to measure the bound label. The TRF assay was successfully used to demonstrate the ND4/11778 mutation in patient samples. For quantification of heteroplasmy, synthetic target oligonucleotide mixtures with known ratios of wild-type and mutated sequences were used as standards to control the hybridization step. The assay allowed the detection of heteroplasmy ranging from 5 to 95%. This was also shown in a family with several heteroplasmic members.
Collapse
Affiliation(s)
- K Huoponen
- Department of Medical Genetics, University of Turku, Finland
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Diamandis EP. Time-resolved fluorometry in nucleic acid hybridization and western blotting techniques. Electrophoresis 1993; 14:866-75. [PMID: 8223395 DOI: 10.1002/elps.11501401138] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Time-resolved fluorometry is now used extensively for immunological assays and to a lesser extent in other research areas. In this review I describe applications of time-resolved fluorometry in nucleic acid hybridization and in blotting techniques, including Southern and Western blotting. Clearly, time-resolved fluorometry has potential for playing a major role in techniques other than immunological assays.
Collapse
Affiliation(s)
- E P Diamandis
- Department of Clinical Biochemistry, Toronto Hospital, Ontario, Canada
| |
Collapse
|
25
|
Hierholzer JC, Halonen PE, Dahlen PO, Bingham PG, McDonough MM. Detection of adenovirus in clinical specimens by polymerase chain reaction and liquid-phase hybridization quantitated by time-resolved fluorometry. J Clin Microbiol 1993; 31:1886-91. [PMID: 8349768 PMCID: PMC265651 DOI: 10.1128/jcm.31.7.1886-1891.1993] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In addition to tests for the group-specific hexon antigen of adenoviruses, adenoviruses can be detected in clinical specimens by hybridization assays utilizing the widely shared base sequences of the region of the hexon gene that codes for the group-reactive determinants. We have developed a liquid-phase hybridization system with biotin- and europium-labeled probes which are reacted after DNA amplification of a 161-bp region of the hexon gene and which are quantitated by time-resolved (TR) fluorometry in streptavidin-coated microtiter wells. Polymerase chain reaction (PCR)-TR fluorometry is not a rapid test in the usual sense, but it is highly useful for specimens with inherent toxicity or with low virus yield, such as organ minces and specimens obtained late in the course of an illness. In a survey of 103 specimens tested by this method, including urine, stool, and tissue suspensions, the agreement with the hexon-specific TR fluoroimmunoassay antigen test for positive specimens was 100% and the sensitivity compared with that of virus culture was 91%. The PCR-TR fluorometry system was also shown to be advantageous as a quantitative measure of PCR products.
Collapse
Affiliation(s)
- J C Hierholzer
- Respiratory and Enteric Viruses Branch, Centers for Disease Control, Atlanta, Georgia 30333
| | | | | | | | | |
Collapse
|
26
|
|
27
|
Iitiä A, Liukkonen L, Siitari H. Simultaneous detection of two cystic fibrosis alleles using dual-label time-resolved fluorometry. Mol Cell Probes 1992; 6:505-12. [PMID: 1480190 DOI: 10.1016/0890-8508(92)90047-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A simple dual-label hybridization test for normal and mutant cystic fibrosis (CF) alleles is described. The assay is based on time-resolved fluorometry (TRF), which allows the simultaneous detection of DNA probes labelled with different lanthanides from one hybridization reaction. DNA was liberated from dried blood disks, normally used in neonatal screening programmes, by boiling in alkaline solution. A 138 bp region including the site of deletion, delta F-508, which is present on about 70% of cystic fibrosis chromosomes, was amplified using the polymerase chain reaction (PCR). The presence or absence of normal and mutant alleles was then determined in a solution hybridization using allele specific oligonucleotide probes labelled either with europium (Eu) or with samarium (Sm) chelates. A common biotinylated probe was used for binding the hybrids onto microtitration wells coated with streptavidin. Some 5 x 10(7) molecules of the normal allele (Eu) and 5 x 10(8) molecules of the mutant allele (Sm) could be detected simultaneously in a single hybridization reaction. The assay was simple to perform and made it possible to reduce the number of hybridizations needed to interpret the sample as being normal, carrier or mutant with regard to the mutation, delta F-508.
Collapse
|
28
|
Iitiä A, Høgdall E, Dahlen P, Hurskainen P, Vuust J, Siitari H. Detection of mutation delta F508 in the cystic fibrosis gene using allele-specific PCR primers and time-resolved fluorometry. PCR METHODS AND APPLICATIONS 1992; 2:157-62. [PMID: 1477671 DOI: 10.1101/gr.2.2.157] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A method to detect the main cystic fibrosis (CF) mutation delta F508 from dried blood spots, whole blood, or saliva using the polymerase chain reaction (PCR) and time-resolved fluorometry (TRF) is described. Samples are treated by boiling in mild alkaline solution, after which two allele-specific PCR reactions are performed. Allele-specific primers and a common biotinylated primer are used in the amplification reactions. To detect the PCR product, an europium-labeled oligonucleotide, complementary to the biotinylated strand of the PCR product, is used in a solution hybridization. Hybridization is done in streptavidin-coated microtitration wells, making the detection easy to perform. After a washing step, the bound label is detected using a time-resolved fluorometer. To analyze function of the assay, 20 dried blood spot samples were tested. PCR amplification of the deletion region combined with gel retardation assay was used as a control method. In the initial testing, 2 samples giving discrepant results in the two assays were found. In addition, 17 samples from known CF patients together with 6 normal control samples were analyzed. Among these patient samples, 10 homozygotes and 6 carriers for mutation delta F508 were found.
Collapse
|
29
|
Evangelista RA, Wong HE, Templeton EF, Granger T, Allore B, Pollak A. Alkyl- and aryl-substituted salicyl phosphates as detection reagents in enzyme-amplified fluorescence DNA hybridization assays on solid support. Anal Biochem 1992; 203:218-26. [PMID: 1416020 DOI: 10.1016/0003-2697(92)90306-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nine salicyl phosphate esters with hydrophobic substituents (5-phenyl, 5-(2,4-difluorophenyl), 5-tert-octyl, 5-cumyl, 5-(4-tert-butylphenyl, 5-(1-adamantyl), 5-(n-dodecyl), 5-(1,1-diphenylethyl, and 5-trityl) were synthesized and found to be good substrates for calf intestinal alkaline phosphatase. The enzymatic hydrolysis produced the corresponding salicylates, which were strongly fluorescent when excited by ultraviolet light around 300 nm with maximum emission at 420-435 nm. The salicylates were less soluble and/or more adhesive than the nonfluorescent salicyl phosphate substrates, resulting in localization of fluorescence signal, which is a requirement for membrane-based assays. The salicyl phosphates bearing 8-14 carbon substitutents were found to be suitable detection reagents for dot-blot DNA hybridization assays on nylon membrane using a biotinylated probe, allowing the detection of 125 pg of target pBR322 plasmid DNA using a simple apparatus consisting of a transilluminator, a camera. and a 455-nm cutoff optical filter.
Collapse
|
30
|
Iitiä A, Dahlen P, Nunn M, Mukkala VM, Siitari H. Detection of amplified HTLV-I/-II viral sequences using time-resolved fluorometry. Anal Biochem 1992; 202:76-81. [PMID: 1621988 DOI: 10.1016/0003-2697(92)90209-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Since its discovery, the polymerase chain reaction (PCR) has been used for different purposes in the field of DNA research. We tested the PCR for the diagnosis of HTLV-I/-II infections. PCR was used to amplify 141- and 149-base pair regions from the HTLV-I and HTLV-II virus genomes, respectively. The annealing temperature in the PCR amplification was optimized using 20% polyacrylamide gels and silver staining. Even a slight change (3 degrees C) in the annealing temperature had an effect on the specificity of the reaction. The PCR products were detected with biotin and Eu-labeled oligonucleotide probes in a solution hybridization format. The linearity of the assay was tested with serial dilutions of purified chromosomal DNA containing integrated HTLV-II sequences. The linearity was found to be dependent on the number of cycles used in the PCR amplification. The best linearity, at a target level of a few copies, was achieved using a low number of cycles. The specificity of the assay was tested using HTLV-I and HTLV-II-infected lymphocytes from the cell lines Hut102 and MO480, respectively. No cross reactivity between these analytes was observed.
Collapse
Affiliation(s)
- A Iitiä
- Pharmacia Genetic Engineering, La Jolla, California 92037
| | | | | | | | | |
Collapse
|
31
|
Diamandis EP, Christopoulos TK, Bean CC. Quantitative Western blot analysis and spot immunodetection using time-resolved fluorometry. J Immunol Methods 1992; 147:251-9. [PMID: 1372335 DOI: 10.1016/s0022-1759(12)80015-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We describe a new method of staining and quantification of proteins blotted or spotted on nitrocellulose. Blotted or spotted proteins are first reacted with specific antibodies followed by reaction with biotinylated secondary antibodies. The immunocomplex is then reacted with a streptavidin-based macromolecular complex labeled with the fluorescent europium chelate of 4,7-bis(chlorosulfophenyl) 1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA). The fluorescent spots or bands can then be assessed by visual inspection under UV illumination, by instant photography or quantified by scanning with a time-resolved fluorometer. The method does not involve enzyme detection, is simple, sensitive and gives sharp bands which remain fluorescent for long periods of time (months to years).
Collapse
Affiliation(s)
- E P Diamandis
- Department of Clinical Biochemistry, Toronto Western Hospital, Ontario, Canada
| | | | | |
Collapse
|
32
|
Dahlén PO, Iitiä AJ, Skagius G, Frostell A, Nunn MF, Kwiatkowski M. Detection of human immunodeficiency virus type 1 by using the polymerase chain reaction and a time-resolved fluorescence-based hybridization assay. J Clin Microbiol 1991; 29:798-804. [PMID: 1890180 PMCID: PMC269873 DOI: 10.1128/jcm.29.4.798-804.1991] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The polymerase chain reaction (PCR) has many potential applications in the field of nucleic acid diagnostics. In particular, it has been successfully applied to the detection of pathogens present in low copy numbers such as the human immunodeficiency virus type 1. Here we describe a time-resolved fluorescence-based hybridization assay which, combined with the PCR, offers an extremely sensitive method for the detection of nucleic acids. In this assay format, the PCR is run by standard procedures and the subsequent hybridization reaction is carried out in solution by using two oligonucleotide probes, one biotinylated and one labeled with europium (Eu3+). The sandwich hybrids are then collected onto a streptavidin-coated microtitration well, and the bound Eu3+ is measured in a time-resolved fluorometer. This assay is rapid, user friendly, and quantitative and lends itself to automation. The application of this assay to the detection of human immunodeficiency virus type 1 is described.
Collapse
Affiliation(s)
- P O Dahlén
- Pharmacia Genetic Engineering Inc., La Jolla, California 92037
| | | | | | | | | | | |
Collapse
|
33
|
Dahlén P, Iitiä A, Mukkala VM, Hurskainen P, Kwiatkowski M. The use of europium (Eu3+) labelled primers in PCR amplification of specific target DNA. Mol Cell Probes 1991; 5:143-9. [PMID: 2072935 DOI: 10.1016/0890-8508(91)90009-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The polymerase chain reaction (PCR) has many potential applications in the field of DNA probe diagnostics. Here we describe a method that utilizes PCR and time-resolved fluorometry (TRF) for the detection of specific target DNA. First the DNA segment to be detected is amplified according to standard procedures. Then a pair of europium (Eu3+) and biotin-labelled primers nested within the amplified fragment is incorporated in a few additional PCR cycles. Thus amplified DNA fragments are generated that contain an affinity label (biotin) and a detectable label (europium). The doubly-labelled amplified DNA fragments are collected onto streptavidin coated microtitration strips and the bound Eu3+ is measured in a time-resolved fluorometer. We show here the application of this method to the detection of HIV-1 DNA. As few as five copies of HIV-1 DNA could readily be detected using this assay. The method described here is sensitive, rapid and easy to employ. In addition it lends itself to automation.
Collapse
Affiliation(s)
- P Dahlén
- Pharmacia Genetic Engineering Inc., La Jolla, CA 92037
| | | | | | | | | |
Collapse
|
34
|
Diamandis EP. Analytical methodology for immunoassays and DNA hybridization assays--current status and selected systems--critical review. Clin Chim Acta 1990; 194:19-50. [PMID: 2073753 DOI: 10.1016/0009-8981(90)90302-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Immunoassay is an established technique which has contributed enormously to biomedical analysis. DNA hybridization (DNA probing) methodology is emerging as the most promising new discipline of laboratory medicine with potential applications in areas such as genetics, pathology, microbiology and oncology. In this review, immunoassay and DNA probing methodologies are considered together because of their many similarities in assay design and labeling systems. Selected labeling systems are described in this paper in order to stress strategies, general principles and future trends. Special attention has been given to systems that introduce linear or exponential amplification. In the author's view, such systems will dominate in future applications. It is anticipated that during the next decade, immunoassay and DNA probing assays will be carried out on completely automated systems.
Collapse
Affiliation(s)
- E P Diamandis
- Department of Clinical Biochemistry, Toronto Western Hospital, Ontario, Canada
| |
Collapse
|