TY - JOUR A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Hösl, Simone A1 - Scheler, C. A1 - Roos, P.H. A1 - Linscheid, M.W. T1 - Comparison of different chelates for lanthanide labeling of antibodies and application in a Western blot immunoassay combined with detection by laser ablation (LA-)ICP-MS N2 - We have developed lanthanide labeling strategies for antibodies to adapt conventional biochemical workflows like Western blot immunoassays for detection by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis with a special interest to apply the multi-element capabilities of ICP-MS for the design of multiplexed immunoassays. In this paper the lanthanide labeling of antibodies with MeCAT was investigated and the reaction conditions were optimized for application in a Western blot immunoassay analyzed by LA-ICP-MS. Furthermore, the MeCAT labeling strategy was compared with two other commercially available labeling reagents, MAXPAR™ and SCN-DOTA. As a proof-of-principle experiment chemically induced alterations of cytochrome P450 protein expression were investigated and the suitability of the differentially labeled antibodies for Western blot immunoassays of a complex liver microsomal protein fraction was tested. Limits of detection (LODs) in the lower fmol range were reached in the Western blot application using MeCAT and MAXPAR™ as element labeling reagents, whereas even sub-fmol LODs can be achieved in a dot blot experiment for the pure antibodies. PY - 2012 U6 - https://doi.org/10.1039/c2ja30068k SN - 0267-9477 SN - 1364-5544 N1 - Geburtsname von Müller, Larissa: Wäntig, L. - Birth name of Müller, Larissa: Wäntig, L. N1 - Geburtsname von Hösl, Simone: Hardt, S. - Birth name of Hösl, Simone: Hardt, S. VL - 27 IS - 8 SP - 1311 EP - 1320 PB - Royal Society of Chemistry CY - London AN - OPUS4-26256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Techritz, Sandra A1 - Jakubowski, Norbert A1 - Roos, P.H. T1 - A multi-parametric microarray for protein profiling: simultaneous analysis of 8 different cytochromes via differentially element tagged antibodies and laser ablation ICP-MS N2 - The paper presents a new multi-parametric protein microarray embracing the multi-analyte capabilities of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The combination of high throughput reverse phase protein microarrays with element tagged antibodies and LA-ICP-MS makes it possible to detect and quantify many proteins or biomarkers in multiple samples simultaneously. A proof of concept experiment is performed for the analysis of cytochromes particularly of cytochrome P450 enzymes, which play an important role in the metabolism of xenobiotics such as toxicants and drugs. With the aid of the LA-ICP-MS based multi-parametric reverse phase protein microarray it was possible to analyse 8 cytochromes in 14 different proteomes in one run. The methodology shows excellent detection limits in the lower amol range and a very good linearity of R² ≥ 0.9996 which is a prerequisite for the development of further quantification strategies. KW - Multi-parametric KW - Multiplexing KW - Microarray KW - Immunoassay KW - LA-ICP-MS KW - Cytochrome P450 PY - 2013 U6 - https://doi.org/10.1039/c3an00468f SN - 0003-2654 SN - 1364-5528 VL - 138 IS - 21 SP - 6309 EP - 6315 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-29275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roos, P.H. A1 - Jakubowski, Norbert T1 - Methods for the discovery of low-abundance biomarkers for urinary bladder cancer in biological fluids N2 - For the study of bladder cancer and the identification of respective tumor markers, blood and, in particular, urine constitute suitable sources of biological material, while both harboring their specific challenges for analytics concerning low-abundance biomarkers. Dissolved proteins and nucleic acids as well as cells and cell-bound molecules can be the analytes. In urine, exfoliated bladder tumor cells have to be identified and in blood, circulating tumor cells have to be detected among huge amounts of other cells. For the detection of both low-abundance cells and molecules, their specific enrichment prior to analysis is advantageous or even necessary. Adapted methods for the analysis of proteomes and subproteomes by 2D-gel electrophoresis, multidimensional chromatography and antibody arrays are discussed. Analysis of nucleic acid-based markers exploits the high amplification power of PCR and modified PCR combined with previous (subtransciptomes) or subsequent (microarray) enrichment to sensitively and specifically detect markers. DNA mutations, DNA-methylation status and apoptotic DNA fragments, as well as levels of ribonucleic acids including microRNAs, can be analyzed by means of these methods. Finally, the challenge of identifying circulating tumor cells and assigning them to their original tissue is critically discussed. PY - 2010 U6 - https://doi.org/10.4155/BIO.09.174 SN - 1757-6180 VL - 2 IS - 2 SP - 295 EP - 309 PB - Future Science Group CY - London AN - OPUS4-20981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jakubowski, Norbert A1 - Prohaska, T. A1 - Roos, P.H. ED - Beauchemin, D. ED - Matthews, D. T1 - Polyatomic ions with double-focusing magnet sector mass spectrometers KW - ICP-MS KW - Sektorfeldgeräte PY - 2010 SN - 978-0-08-043804-7 VL - 5 SP - 132 EP - 150 PB - Elsevier CY - Oxford, UK AN - OPUS4-22237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roos, P.H. A1 - Jakubowski, Norbert T1 - Cytochromes - fascinating molecular machines N2 - A huge number of functions and reactions can be performed by proteins merely based on their amino acids and their spatial arrangement which results in a specific geometric and electronic environment. The diversity and efficiency of functions, however, can be increased by protein-bound cofactors which fulfil their task in close interaction with the surrounding amino acid side chains. Among these cofactors, metals play an important role. They can be bound to proteins directly via specific amino acids such as cysteine and histidine, for example in zinc finger proteins or in iron sulfur cluster proteins. Another possibility is their integration into the 3D-structure of a protein via a prosthetic group. Porphyrine or porphyrine-like molecules with copper or iron as central bound metal ions constitute important structures in this respect. PY - 2011 U6 - https://doi.org/10.1039/c1mt90012a SN - 1756-5901 SN - 1756-591X VL - 3 SP - 316 EP - 318 PB - RSC Publ. CY - Cambridge AN - OPUS4-23830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Hayen, H. A1 - Roos, P.H. T1 - Iodination of proteins, proteomes and antibodies with potassium triodide for LA-ICP-MS based proteomic analyses N2 - A fast and mild method for iodine labelling of proteins is presented which is specifically designed and optimized for laser ablation (LA-)ICP-MS based proteomics. Single proteins (lysozyme, bovine serum albumin, cytochrome c and β-casein), whole proteomes (microsomal proteome of rats) and antibodies (anti-bovine casein, anti-bovine serum albumin) can be efficiently iodinated by means of potassium triiodide with minimal losses of antigen properties and antibody binding to iodinated proteins. A comparison with iodination by use of IODO-Beads is presented and it is shown that triiodide labelling is a fast, cheap and less laborious alternative without compromising the analytical figures of merit. PY - 2011 U6 - https://doi.org/10.1039/c1ja10090d SN - 0267-9477 SN - 1364-5544 N1 - Geburtsname von Müller, Larissa: Wäntig, L. - Birth name of Müller, Larissa: Wäntig, L. VL - 26 SP - 1610 EP - 1618 PB - Royal Society of Chemistry CY - London AN - OPUS4-24209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Roos, P.H. T1 - Multi-parametric analysis of cytochrome P450 expression in rat liver microsomes by LA-ICP-MS N2 - Quantitative analysis of cytochrome P450 (CYP) patterns of cells and tissues is an important aspect in toxicological and pharmacological research as this group of enzymes is largely involved in the metabolism of toxic compounds and drugs. Here we present a method for the multi-parametric and simultaneous quantitative determination of several cytochromes P450 in liver microsomes of untreated and inducer treated rats. The method is based on the binding of specifically lanthanide labelled antibodies to electrophoretically separated and blotted CYP proteins and their subsequent identification and quantification by LA-ICP-MS. CYP1A1, CYP2B1, CYP2C11, CYP2E1 and CYP3A1 were simultaneously quantified and the patterns between microsomal samples were compared. Microsomes of rats treated with 3-methylcholanthrene, phenobarbital and dexamethasone showed increased levels of CYP1A1, CYP2B1 and CYP3A1, respectively. These results coincide with data obtained by independent methods for CYP quantification, i.e. ethoxyresorufin O-deethylase activity for CYP1A1 and pentoxyresorufin O-depentylase for CYP2B1. The presented method is useful for multi-parametric CYP profiling and has further large potential with respect to the number of analysed parameters/proteins and sensitivity. PY - 2011 U6 - https://doi.org/10.1039/c0ja00077a SN - 0267-9477 SN - 1364-5544 N1 - Geburtsname von Müller, Larissa: Wäntig, L. - Birth name of Müller, Larissa: Wäntig, L. VL - 26 IS - 2 SP - 310 EP - 319 PB - Royal Society of Chemistry CY - London AN - OPUS4-23465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Jakubowski, Norbert A1 - Horsky, M. A1 - Roos, P.H. A1 - Vanhaecke, F. A1 - Prohaska, T. ED - Prohaska, T. ED - Irrgeher, J. ED - Zitek, A. ED - Jakubowski, Norbert T1 - Inductively coupled plasma mass spectrometry N2 - ICP-MS is based on the formation of (preferentially monovalent positively)charged atomic ions in an inductively coupled Ar plasma at almost 10 000 K. The ions formed are transferred from the plasma source at ambient pressure into a mass Separator operated at high vacuum via a set of cones. The ions are separate«! according to their mass/charge ratio in the mass Separator (quadrupole, magnetic sector field or time-of-flight mass Separator). In most cases, the ions are detected using a secondaiy electron multiplier; in some set-ups (also) a Faraday cup can be used. Single-collector (scanning mass spectrometer usually used for quantitative elemental analysis) or multicollector (static Operation of mass spectrometer for precise isotope ratio analysis) configurations can be found. PY - 2015 SN - 978-1-84973-392-2 SN - 978-1-84973-540-7 SN - 2044-253X N1 - Serientitel: New developments in mass spectrometry – Series title: New developments in mass spectrometry Vollständiges Belegexemplar liegt nur beim Autor vor! VL - 3 SP - Chapter 12, 208 EP - 318 CY - Cambridge, UK AN - OPUS4-33074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giesen, Charlotte A1 - Müller, Larissa A1 - Mairinger, T. A1 - Drescher, Daniela A1 - Kneipp, Janina A1 - Roos, P.H. A1 - Panne, Ulrich A1 - Jakubowski, Norbert T1 - Iodine as an elemental marker for imaging of single cells and tissue sections by laser ablation inductively coupled plasma mass spectrometry N2 - A new laser ablation (LA)-ICP-MS method for single cell and cell nucleus imaging was developed. Therein, iodine was employed as an elemental dye for fibroblast cells and for thin tissue sections. At an incubation time of 60 s, iodine is located mainly within the cell nuclei. This effect was illustrated in fibroblast cells, and iodine signal within the cell nucleus was as high as 5 × 104 cps at 4 µm laser spot size. The surrounding cytoplasm was iodinated as well, but to a lesser extent. The spatial resolution attained was sufficient to detect even smaller cell nuclei within a liver biopsy tissue. Furthermore, iodine was successfully employed for biomolecule labeling and we demonstrated that iodine signal increased with increasing thickness of a palatine tonsil tissue. Thus, the use of iodine as an internal standard to correct for tissue inhomogeneities in LA-ICP-MS was investigated for the simultaneous detection of two tumor markers (Her 2 and CK 7) in breast cancer tissue. Additionally, lanthanide background resulting from glass ablation can be corrected for by Eu standardization. PY - 2011 U6 - https://doi.org/10.1039/c1ja10227c SN - 0267-9477 SN - 1364-5544 N1 - Geburtsname von Müller, Larissa: Wäntig, L. - Birth name of Müller, Larissa: Wäntig, L. VL - 26 IS - 11 SP - 2160 EP - 2165 PB - Royal Society of Chemistry CY - London AN - OPUS4-24964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -