Gerrit Hermann (Presenter)
University of Vienna
Bio: Apr 2014 – date: Postdoc at the University of Vienna, faculty of chemistry, department of analytical chemistry ->Planning and commissioning of clean room laboratories dedicated for LC-MS and LC-ICP-MS instruments ->Research in metabolomics ->Speciation in Metallodrug research ->Quantification of small molecules in samples of cancer cell cultures ->Developments in the sample preparation ->Development of new analytical methods Jul 2015 – date: Founding project: University-Spin-off ISOtopic solutions e.U. Isotopic solutions e.U. is a spin-off of the University of Vienna. Main object of the company is to support the research through production and distribution of stable isotope-labeled internal standards for mass spectrometry. Sep 2010 – Mar 2014: Phd. thesis in the field of Analytical Chemistry/Bioanalytics Title of Phd. thesis: Mass spectrometry based assays in the field of preclinical metallodrug research @ University for natural resources and life sciences Vienna, Institute of Analytical Chemistry (Passed with distinction) Oct 2008 – May 2010: Engineering studies Biotechnology Title of the diploma thesis: Analysis of (poly)phenol compounds in red wine @ University for natural resources and life sciences Vienna, Institute of Analytical Chemistry (Passed with distinction)
Authorship: Michaela Schwaiger (1), Gerrit Hermann (1, 2), Petra Volejnik (1), Mate Rusz (1), Evelyn Rampler (1), Walter Miklos (3), Walter Berger (3), Gunda Koellensperger (1)
(1) University of Vienna, Department of Analytical Chemistry, Austria (2) ISOtopic solutions e.U., Vienna, Austria (3) Medical University of Vienna, Institute of Cancer Research, Austria
| Short Abstract Mass spectrometry (MS) is already a powerful tool for quantification of metabolites in cancer research and is constantly gaining importance. Nevertheless, through unintentional variations in sample preparation and measurement results are often compromised. To tackle these problems we applied uniformly labeled internal standards (IS). These IS derived from U13C isotopically labelled yeast. As eukaryotic organism yeast shares most of the primary mammalian metabolism and thereby it can be exploited as source for IS. We covered molecules of the Krebs cycle, glycolysis as well as nucleotides, nucleosides and nucleobases in a comparative study of a resistant vs. a non-resistant cancer cell line. Additionally the application of these IS extended the working range and offered the opportunity to accomplish targeted and non-targeted metabolomics at the same time when high resolution MS was applied |
Long Abstract
Mass spectrometry (MS) is a powerful tool for quantification of metabolites in cancer research. Nevertheless, through unintentional variations in sample preparation and measurement the repeatability of analytical results is often compromised. Matrix effects and saturation of the detector disturb quantitative investigations of relevant metabolites. We wanted to cover molecules of the Krebs cycle, glycolysis as well as nucleotides, nucleosides and nucleobases in a comparative study of a resistant vs. a non-resistant cancer cell line. To tackle the problems in the sample preparation and measurement process we applied uniformly labelled internal standards to compensate for error sources occurring during sample procession and measurement. The major problem here was the availability of internal standards for many molecules, respectively to cover a huge portfolio of metabolites in an efficient way considering time, handling and availability.
The solution of the problem was found in internal standards produced by in-vivo labelling. Using this method, cells are grown on an isotopically enriched 13C growth media. These cells can be harvested and extracted to obtain an isotopically enriched extract of the metabolome that can be exploited as internal standard for a plethora of metabolites. As yeast can be cultivated on minimal media isotopically enrichment of > 99% was achieved.
As eukaryotic organisms yeasts and mammalian cells have most of the primary metabolism in common, the application of standards derived from U13C isotopically labelled yeast improved the trueness and precision of the measurement results for many metabolites. The application of substance specific internal standardization also extended the scope of mass spectrometry in terms of working range and offered the opportunity to accomplish targeted and non-targeted metabolomics at the same time when high resolution mass spectrometry was applied. In course of this investigation we encountered that there are differences in the concentration levels of certain metabolites when resistant and non-resistant cells are compared.
A protocol published by Dettmer et al. was adopted for preparation of adherent cell cultures [1]. Measurements were carried out via LC-MS/MS and LC-High resolution mass spectrometry in combination with ion chromatography, hydrophilic interaction chromatography and reversed phase chromatography.
[1] K. Dettmer et al., Metabolite extraction from adherently growing mammalian cells for metabolomics studies: optimization of harvesting and extraction protocols, Anal. Bioanal. Chem. 399 (2011) 1127–1139.
References & Acknowledgements:
| Description | Y/N | Source |
| Grants | no | |
| Salary | no | |
| Board Member | no | |
| Stock | no | |
| Expenses | yes | ISOtopic solutions e.U. |
IP Royalty: no
| Planning to mention or discuss specific products or technology of the company(ies) listed above: | yes |