Listen
4 Ergebnisse
Filter
Einstellungen
Suchergebnisse
Veröffentlichung Sulfur and nitrogen mustards induce characteristic poly(ADP-ribosyl)ation responses in HaCaT keratinocytes with distinctive cellular consequences(2016) Mangerich, Aswin; Debiak, Malgorzata; Birtel, Matthias; Ponath, Viviane; Balszuweit, Frank; Lex, Kirsten; Martello, Rita; Burckhardt-Boer, Waltraud; Strobelt, Romano; Siegert, Markus; Thiermann, Horst; Steinritz, Dirk; Schmidt, Annette; Bürkle, AlexanderMustard agents are potent DNA alkylating agents with mutagenic, cytotoxic and vesicant properties. They include bi-functional agents, such as sulfur mustard (SM) or nitrogen mustard (mustine, HN2), as well as mono-functional agents, such as "half mustardŁ (CEES). Whereas SM has been used as a chemical warfare agent, several nitrogen mustard derivatives, such as chlorambucil and cyclophosphamide, are being used as established chemotherapeutics. Upon induction of specific forms of genotoxic stimuli, several poly(ADP-ribose) polymerases (PARPs) synthesize the nucleic acid-like biopolymer poly(ADP-ribose) (PAR) by using NAD+ as a substrate. Previously, it was shown that SM triggers cellular poly(ADP-ribosyl) ation (PARylation), but so far this phenomenon is poorly characterized. In view of the protective effects of PARP inhibitors, the latter have been proposed as a treatment option of SM-exposed victims. In an accompanying article (Debiak et al., 2016), we have provided an optimized protocol for the analysis of the CEES-induced PARylation response in HaCaT keratinocytes, which forms an experimental basis to further analyze mustard-induced PARylation and its functional consequences, in general. Thus, in the present study, we performed a comprehensive characterization of the PARylation response in HaCaT cells after treatment with four different mustard agents, i.e., SM, CEES, HN2, and chlorambucil, on a qualitative, quantitative and functional level. In particular, we recorded substance-specific as well as dose- and time-dependent PARylation responses using independent bioanalytical methods based on single-cell immuno-fluorescence microscopy and quantitative isotope dilution mass spectrometry. Furthermore, we analyzed if and how PARylation contributes to mustard-induced toxicity by treating HaCaT cells with CEES, SM, and HN2 in combination with the clinically relevant PARP inhibitor ABT888. As evaluated by a novel immunofluorescence-based protocol for the detection of N7-ETE-guanine DNA adducts, the excision rate of CEES-induced DNA adducts was not affected by PARP inhibition. Furthermore, while CEES induced moderate changes in cellular NAD+ levels, annexin V/PI flow cytometry analysis revealed that these changes did not affect CEES-induced short-term cytotoxicity 24 h after treatment. In contrast, PARP inhibition impaired cell proliferation and clonogenic survival, and potentiated micronuclei formation of HaCaT cells upon CEES treatment. Similarly, PARP inhibition affected clonogenic survival of cells treated with bi-functional mustards such as SM and HN2. In conclusion, we demonstrate that PARylation plays a functional role in mustard-induced cellular stress response with substance-specific differences. Since PARP inhibitors exhibit therapeutic potential to treat SM-related pathologies and to sensitize cancer cells for mustard-based chemotherapy, potential long-term effects of PARP inhibition on genomic stability and carcinogenesis should be carefully considered when pursuing such a strategy.Quelle: http://www.sciencedirect.comVeröffentlichung Two birds with one stone - fast and simultaneous analysis of microplastics(2018) Eisentraut, Paul; Dümichen, Erik; Ruhl, Aki SebastianAnalysis of microplastic particles in environmental samples needs sophisticated techniques and is time intensive due to sample preparation and detection. Alternatives to the most common (micro-) spectroscopic techniques, Fourier transform infrared and Raman spectroscopy, are thermoanalytical methods, in which specific decomposition products can be analyzed as marker compounds for different kinds of plastic types and mass contents. Thermal extraction desorption gas chromatography-mass spectrometry allows the fast identification and quantification of MP in environmental samples without sample preparation. Whereas to date only the analysis of thermoplastic polymers has been realized, this is the first time that even the analysis of tire wear (TW) content in environmental samples has been possible. Various marker compounds for TW were identified. They include characteristic decomposition products of elastomers, antioxidants, and vulcanization agents. Advantages and drawbacks of these marker substances were evaluated. Environmental samples from street runoff were exemplarily investigated, and the results are presented. © 2018 American Chemical Society.Veröffentlichung Determination of microplastic mass content by thermal extraction desorption gas chromatography-mass spectrometry(2021) Wiesner, Yosri; Altmann, Korinna; Braun, UlrikeThe scientific and practical challenge of detecting microplastics (MPs) in the environment in a targeted and rapid manner is solved by innovative coupling of thermogravimetric analysis with mass spectrometric methods. Fast identification and quantitative determination of most thermoplastic polymers and elastomers is possible by using thermal extraction desorption gas chromatography-mass spectrometry (TED-GC-MS). © AuthorsVeröffentlichung Decomposability versus detectability: First validation of TED-GC/MS for microplastic detection in different environmental matrices(2023) Kittner, Maria; Eisentraut, Paul; Braun, UlrikeA fast method for microplastic detection is thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), which uses polymer-specific thermal decomposition products as marker compounds to determine polymer mass contents in environmental samples. So far, matrix impacts of different environmental matrices on TED-GC/MS performance had not yet been assessed systematically. Therefore, three solid freshwater matrices representing different aquatic bodies with varying organic matter contents were spiked with a total of eight polymers. Additionally, for the first time, the two biodegradable polymers polybutylene adipate terephthalate (PBAT) and polylactide (PLA) were analysed using TED-GC/MS. The methodological focus of this work was on detectability, quality of signal formation as well as realisation of quantification procedures and determination of the limit of detection (LOD) values. Overall, TED-GC/MS allowed the unambiguous detection of the environmentally most relevant polymers analysed, even at low mass contents: 0.02wt% for polystyrene (PS), 0.04wt% for the tyre component styrene butadiene rubber (SBR) and 0.2wt% for polypropylene (PP), polyethylene (PE) and PBAT. Further, all obtained LOD values were increased in all matrices compared to the neat polymer without matrix. The LOD of the standard polymers were increased similarly (PS: 0.21-0.34 (micro)g, SBR: 0.27-0.38 (micro)g, PP: 0.32-0.36 (micro)g, PMMA: 0.64-1.30 (micro)g, PET: 0.90-1.37 (micro)g, PE: 3.80-6.99 (micro)g) and their decompositions by radical scission processes were not significantly influenced by the matrices. In contrast, matrix-specific LOD increases of both biodegradable polymers PBAT (LOD: 1.41-7.18 (micro)g) and PLA (0.84-20.46 (micro)g) were observed, probably due to their hetero-functional character and interactions with the matrices. In conclusion, the TED-GC/MS performance is not solely determined by the type of the polymers but also by the composition of the matrix. © 2023 Wiley VCH GmbH