TY - JOUR A1 - Lisec, Jan A1 - Jaeger, C. A1 - Zaidi, Nousheen T1 - Cancer cell lipid class homeostasis is altered under nutrient-deprivation but stable under hypoxia N2 - Under oxygen/nutrient deprivation cancer cells modify the Balance between fatty acid (FA) synthesis and uptake, which alters the levels of individual triglyceride or phospholipid sub-species. These modifications may affect survival and drug-uptake in cancer cells. Here, we aimed to attain a more holistic overview of the lipidomic profiles of cancer cells under stress and assess the changes in Major lipid-classes. First, expressions of markers of FA synthesis/uptake in cancer cells were assessed and found to be differentially regulated under metabolic stress. Next, we performed a broad lipidomics assay, comprising 244 lipids from six major classes, which allowed us to investigate robust stress induced changes in median levels of different lipid classes -additionally stratified by fatty acid side chain saturation status. The lipidomic profiles of cancer cells were predominantly affected by nutrient-deprivation. Neutral lipid compositions were markedly modified under serum-deprivation and, strikingly, the cellular level of triglyceride subspecies decreased with increasing number of double bonds in their fatty acyl chains. In contrast, cancer cells maintained lipid class homeostasis under hypoxic stress. We conclude that although the levels of individual lipid moieties alter under hypoxia, the robust averages of broader lipid class remain unchanged. KW - Mass-Spectrometry KW - Tumor metabolism KW - Fatty acid metabolism KW - Lipidomic profile KW - Metabolic stress PY - 2018 DO - https://doi.org/10.1101/382457 SP - 1 EP - 25 PB - Cold Spring Harbor Laboratory CY - Cold Spring Harbor, NY AN - OPUS4-46814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tjaden, B. A1 - Baum, K. A1 - Marquardt, V. A1 - Simon, M. A1 - Trajkovic-Arsic, M. A1 - Kouril, T. A1 - Siebers, B. A1 - Lisec, Jan A1 - Siveke, J. T. A1 - Schulte, J. H. A1 - Benary, U. A1 - Remke, M. A1 - Wolf, J. A1 - Schramm, A. T1 - MYCN-induced metabolic rewiring creates novel therapeutic vulnerabilities in neuroblastoma N2 - MYCN is a transcription factor that is aberrantly expressed in many tumor types and is often correlated with poor patient prognosis. Recently, several lines of evidence pointed to the fact that oncogenic activation of MYC family proteins is concomitant with reprogramming of tumor cells to cope with an enhanced need for metabolites during cell growth. These adaptions are driven by the ability of MYC proteins to act as transcriptional amplifiers in a tissue-of-origin specific manner. Here, we describe the effects of MYCN overexpression on metabolic reprogramming in neuroblastoma cells. Ectopic expression of MYCN induced a glycolytic switch that was concomitant with enhanced sensitivity towards 2-deoxyglucose, an inhibitor of glycolysis. Moreover, global metabolic profiling revealed extensive alterations in the cellular metabolome resulting from overexpression of MYCN. Limited supply with either of the two main carbon sources, glucose or glutamine, resulted in distinct shifts in steady-state metabolite levels and significant changes in glutathione metabolism. Interestingly, interference with glutamine-glutamate conversion preferentially blocked proliferation of MYCN overexpressing cells, when glutamine levels were reduced. Thus, our study uncovered MYCN induction and nutrient levels as important metabolic master switches in neuroblastoma cells and identified critical nodes that restrict tumor cell proliferation. KW - Mass-spectrometry KW - Tumor metabolism KW - MYCN PY - 2018 DO - https://doi.org/10.1101/423756 SP - 1 EP - 21 PB - Cold Spring Harbor Laboratory CY - Cold Spring Harbor, NY AN - OPUS4-46815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppen, Robert A1 - Kroh, L.W. A1 - Lörchner, Dominique T1 - 1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione: kinetic studies and phototransformation products N2 - 1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBP-TAZTO) is an emerging brominated flame retardant which is widely used in several plastic materials (electric and electronic equipment, musical instruments, automotive components). However, until today, no photochemical studies as well as the identification of possible phototransformation products (PTPs) were described in literature. Therefore, in this study, UV-(C) and simulated sunlight irradiation experiments were performed to investigate the photolytic degradation of TDBP-TAZTO and to identify relevant PTPs for the first time. The UV-(C) Irradiation experiments show that the photolysis reaction follows a first-order kinetic model. Based on this, the photolysis rate constant k as well as the half-life time t1/2 were calculated to be k = (41 ± 5 ×10−3) min−1 and t1/2=(17±2) min. In comparison, a minor degradation of TDBP-TAZTO and no formed phototransformation products were obtained under simulated sunlight. In order to clarify the photochemical behavior, different chemicals were added to investigate the influence on indirect photolysis: (i) H2O2 for generation of hydroxyl radicals and (ii) two quenchers (2-propanol, sodium azide) for scavenging oxygen species which were formed during the irradiation experiments. Herein, nine previously unknown PTPs of TDBP-TAZTO were detected under UV-(C) irradiation and identified by HPLC-(HR)MS. As a result, debromination, hydroxylation, and dehydrobromination reactions could be presumed as the main degradation pathways by high-resolution mass spectrometry. The direct as well as the OH radical-induced indirect photolysis were observed. KW - UV irradiation KW - HRMS KW - Debromination KW - Hydroxylation KW - Emerging brominated flame retardant PY - 2019 DO - https://doi.org/10.1007/s11356-019-04815-w SN - 0944-1344 VL - 26 IS - 16 SP - 15838 EP - 15846 PB - Springer AN - OPUS4-47857 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Keller, Julia A1 - Borzekowski, Antje A1 - Koch, Matthias T1 - Mykotoxine in Lebensmitteln - Zearalenon und seine Transformationsprodukte N2 - Mykotoxine in Lebensmitteln stellen weltweit Probleme dar, Zearalenon in Speiseöl ist ein solches. Neue Hydrazinbasierte Analyseverfahren können jetzt helfen, den EU-Grenzwert besser zu kontrollieren. Aber auch die Strukturaufklärung von Transformationsprodukten und verlässliche Kalibrierstandards sind aktuelle Herausforderungen. KW - Analyseverfahren KW - Hydrazin KW - Speiseöle KW - Transformationsprodukte PY - 2019 IS - 03 SP - 34 EP - 36 AN - OPUS4-47858 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munir, R. A1 - Lisec, Jan A1 - Swinnen, J. V. A1 - Zaidi, N. T1 - Lipid metabolism in cancer cells under metabolic stress N2 - Cancer cells are often exposed to a metabolically challenging environment with scarce availability of oxygen and nutrients. This metabolic stress leads to changes in the balance between the endogenous synthesis and exogenous uptake of fatty acids, which are needed by cells for membrane biogenesis, energy production and protein modification. Alterations in lipid metabolism and, consequently, lipid composition have important therapeutic implications, as they affect the survival, membrane dynamics and therapy response of cancer cells. In this article, we provide an overview of recent insights into the regulation of lipid metabolism in cancer cells under metabolic stress and discuss how this metabolic adaptation helps cancer cells thrive in a harsh tumour microenvironment. KW - Mass-Spectrometry KW - Lipidomics KW - Lipid metabolism KW - Cancer cells PY - 2019 DO - https://doi.org/10.1038/s41416-019-0451-4 VL - 120 IS - 12 SP - 1090 EP - 1098 PB - Nature AN - OPUS4-48005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Bresch, Harald A1 - Kipphardt, Heinrich A1 - Resch-Genger, Ute A1 - Koch, Matthias A1 - Rosner, M. T1 - Trends in selected fields of reference material production N2 - For more than 110 years, BAM has been producing reference materials for a wide range of application fields. With the development of new analytical methods and new applications as well as continuously emerging more stringent requirements of laboratory accreditation with regard to quality control and metrological traceability, the demand and requirements for reference materials are increasing. This trend article gives an overview of general developments in the field of reference materials as well as developments in selected fields of application in which BAM is active. This includes inorganic and metal analysis, gas analysis, food and consumer products, and geological samples. In addition to these more traditional fields of application, developments in the areas of optical spectroscopy, particulary fluorescence methods, and nanomaterials are considered. T2 - 150 years BAM: Science with impact CY - Berlin, Germany DA - 01.01.2021 KW - Reference material KW - ISO REMCO KW - Gas analysis KW - Food KW - Nanomaterials KW - Fluorescence PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548407 DO - https://doi.org/10.1007/s00216-022-03996-7 SN - 1618-2642 SN - 1618-2650 VL - 414 IS - Topical collection: Analytical methods and applications in the materials and life sciences SP - 4281 EP - 4289 PB - Springer CY - Berlin AN - OPUS4-54840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riedel, Juliane A1 - Recknagel, Sebastian A1 - Sassenroth, Diana A1 - Mauch, Tatjana A1 - Buttler, Sabine A1 - Sommerfeld, Thomas A1 - Penk, Sibylle A1 - Koch, Matthias T1 - Development and certification of a reference material for zearalenone in maize germ oil N2 - Zearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximumlevel for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k=2) of ERM®-BC715 (362± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. KW - Fusarium mycotoxin KW - Vegetable edible oil KW - Food analysis KW - European Reference Material KW - Quality assurance PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531831 DO - https://doi.org/10.1007/s00216-021-03532-z SN - 1618-2642 SN - 1618-2650 VL - 413 IS - 21 SP - 5483 EP - 5491 PB - Springer CY - Berlin AN - OPUS4-53183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Koch, Matthias A1 - Köppen, Robert A1 - Buttler, Sabine A1 - Penk, Sibylle A1 - Mauch, Tatjana A1 - Sommerfeld, Thomas A1 - Witt, Angelika T1 - Development of certified reference materials for the determination of cadmium and acrylamide in cocoa N2 - Since 1 January 2019 a maximum content of 0.6 mg kg−1 cadmium (Cd) in cocoa powder sold to the final consumer or as an ingredient in sweetened cocoa powder sold to the final consumer (drinking chocolate) is set by the Commission Regulation (EU) No. 488/2014. Monitoring compliance with the specified limit value requires analytical measuring methods and reference materials for quality control. However, suitable certified reference materials intended for quality assurance and quality control purposes are still lacking. Therefore, three cocoa reference materials (ERM®-BD513, ERM®-514 and ERM®-515) were developed according to the requirements of ISO 17034 and the recommendations of ISO Guide 35. The whole process of reference material development, including material preparation, assessment of homogeneity and stability, characterisation and value assignment is presented. The assignment of the certified mass fractions was based upon an interlaboratory comparison study involving 19 expert laboratories for Cd and 12 laboratories for acrylamide. The certified mass fractions and expanded uncertainties (k = 2) of the reference materials were (0.181 ± 0.009) mg kg−1 Cd (ERM®-BD513), (0.541 ± 0.024) mg kg−1 Cd (ERM®-BD514) and (0.690 ± 0.029) mg kg−1 Cd (ERM®-BD515). Acrylamide contents are given for information. KW - Certified reference material KW - Quality assurance KW - Cocoa KW - Cadmium KW - Acrylamide KW - Food analysis PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508656 DO - https://doi.org/10.1007/s00216-020-02719-0 SN - 1618-2642 SN - 1618-2650 VL - 412 IS - 19 SP - 4659 EP - 4668 PB - Springer CY - Berlin AN - OPUS4-50865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tukhmetova, Dariya A1 - Lisec, Jan A1 - Vogl, Jochen A1 - Meermann, Björn T1 - Data processing made easy: standalone tool for automated calculation of isotope ratio from transient signals – IsoCor N2 - Despite numerous advantages offered by hyphenation of chromatography and electrokinetic separation methods with multicollector (MC) ICP-MS for isotope analysis, the main limitation of such systems is the decrease in precision and increase in uncertainty due to generation of short transient signals. To minimize this limitation, most authors compare several isotope ratio calculation methods and establish a multi-step data processing routine based on the precision and accuracy of the methods. However, to the best of our knowledge, there is no universal data processing tool available that incorporates all important steps of the treatment of the transient signals. Thus, we introduce a data processing application (App) IsoCor that facilitates automatic calculation of isotope ratios from transient signals and eases selection of the most suitable method. The IsoCor App performs baseline subtraction, peak detection, mass bias correction, isotope ratio calculation and delta calculation. The feasibility and reliability of the App was proven by reproducing the results from isotope analysis of three elements (neodymium, mercury and sulfur) measured on-line via hyphenated systems. The IsoCor App provides trackability of the results to ensure quality control of the analysis. KW - Isotope ratio KW - Transient signal KW - MC-ICP-MS KW - Data processing KW - App PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559068 DO - https://doi.org/10.1039/D2JA00208F VL - 37 IS - 11 SP - 2401 EP - 2409 PB - Royal Society of Chemistry AN - OPUS4-55906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tukhmetova, Dariya A1 - Lisec, Jan A1 - Vogl, Jochen A1 - Meermann, Björn T1 - Development of an Online Isotope Dilution CE/ICP–MS Method for the Quantification of Sulfur in Biological Compounds N2 - We report an analytical methodology for the quantification of sulfur in biological molecules via a speciesunspecific postcolumn isotope dilution (online ID) approach using capillary electrophoresis (CE) coupled online with inductively coupled plasma−mass spectrometry (online ID CE/ICP−MS). The method was optimized using a mixture of standard compounds including sulfate, methionine, cysteine, cystine, and albumin, yielding compound recoveries between 98 and 105%. The quantity of sulfur is further converted to the quantity of the compounds owing to the prior knowledge of the sulfur content in the molecules. The limit of detection and limit of quantification of sulfur in the compounds were 1.3−2.6 and 4.1−8.4 mg L−1, respectively, with a correlation coefficient of 0.99 within the concentration range of sulfur of 5−100 mg L−1. The capability of the method was extended to quantify albumin in its native matrix (i.e., in serum) using experimentally prepared serum spiked with a pure albumin standard for validation. The relative expanded uncertainty of the method for the quantification of albumin was 6.7% (k = 2). Finally, we tested the applicability of the method on real samples by the analysis of albumin in bovine and human sera. For automated data assessment, a software application (IsoCor) which was developed by us in a previous work was developed further for handling of online ID data. The method has several improvements compared to previously published setups: (i) reduced adsorption of proteins onto the capillary wall owing to a special capillary-coating procedure, (ii) baseline separation of the compounds in less than 30 min via CE, (iii) quantification of several sulfur species within one run by means of the online setup, (iv) SI traceability of the quantification results through online ID, and (v) facilitated data processing of the transient signals using the IsoCor application. Our method can be used as an accurate approach for quantification of proteins and other biological molecules via sulfur analysis in complex matrices for various fields, such as environmental, biological, and pharmaceutical studies as well as clinical diagnosis. Sulfur is an essential element in living organisms, where it plays important roles in various biological processes, such as protein synthesis, enzyme activity, and antioxidant defense. However, the biological effects of different sulfur species can vary widely, and imbalances in sulfur speciation have been observed in a range of diseases, including cancer, Alzheimer’s disease, and diabetes.1−3 The accurate quantification of sulfur and its species in biological samples requires sensitive and selective analytical techniques. In recent years, separation techniques coupled online with inductively coupled plasma−mass spectrometry (ICP−MS) have emerged as powerful online analytical tools complementary to molecular spectrometric methods for speciation analysis of biological compounds. External calibration4−9 and isotope dilution (ID)10−15 are common calibration approaches applied for online quantification of sulfur species in complex samples. The ID analysis is advantageous over. KW - Analytical Chemistry KW - CE/MC-ICP-MS KW - species-specific isotope information PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594736 DO - https://doi.org/10.1021/acs.analchem.3c03553 SN - 0003-2700 SP - 1 EP - 8 PB - American Chemical Society (ACS) AN - OPUS4-59473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -