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Microbiologist by training, I am currently working on in-vitro bioassay based risk assessment strategies for the safety evaluation of materials and articles in food contact. As an especially harmful effect to human health, my main focus lies on the evaluation of direct, DNA-reactive genotoxic compounds, as these substancse could potentially induce cancer in humans.
Project Goal: Development of a testing strategy to analyse mineral oil contaminations in food
Current Stage: Data collection
Project Goal: Development of a test strategy for the comprehensive safety assessment of plastic recyclates
Current Stage: Data collection
Project Goal: Development of a testing strategy based on in vitro assays to determine the toxicity of food contact materials
Current Stage: Data collection
With the European Green Deal, the importance of recycled products and materials has increased. Specifically, for PET bottles, a high content of recycled material (rPET) is demanded by the industry and consumers. This study was carried out in a lab environment replicating real-life industrial processes, to investigate the possible impacts on rPET quality over eleven recycling loops, aiming to use high amounts of rPET repetitively. A cycle included extrusion, solid state polycondensation (SSP), a second extrusion to simulate bottle production, hot wash and a drying step. 75% rPET and 25% virgin PET were extruded in eleven cycles to simulate a recycling and production process. Samples underwent chemical, physical and biological analysis. The quality of the rPET material was not adversely affected. Parameters such as coloring, intrinsic viscosity, concentration of critical chemicals and presence of mutagenic contaminants could be positively assessed. The quality of the produced material was likely influenced by the input material’s high standard. A closed loop PET bottle recycling process using an rPET content of up to 75% was possible when following the proposed process, indicating that this level of recycled content can be maintained indefinitely without compromising quality.
Elisabeth Pinter; Frank Welle; Elisa Mayrhofer; Andreas Pechhacker; Lukas Motloch; Vera Lahme; Andy Grant; Manfred Tacker. Circularity Study on PET Bottle-To-Bottle Recycling. Sustainability 2021, 13, 7370 .
AMA StyleElisabeth Pinter, Frank Welle, Elisa Mayrhofer, Andreas Pechhacker, Lukas Motloch, Vera Lahme, Andy Grant, Manfred Tacker. Circularity Study on PET Bottle-To-Bottle Recycling. Sustainability. 2021; 13 (13):7370.
Chicago/Turabian StyleElisabeth Pinter; Frank Welle; Elisa Mayrhofer; Andreas Pechhacker; Lukas Motloch; Vera Lahme; Andy Grant; Manfred Tacker. 2021. "Circularity Study on PET Bottle-To-Bottle Recycling." Sustainability 13, no. 13: 7370.
Meiotic recombination is essential for chromosome segregation at meiosis and fertility. It is initiated by programmed DNA double-strand breaks (DSBs) introduced by Spo11, a eukaryotic homologue of an archaeal topoisomerase (Topo VIA)1. Here we describe previously uncharacterized Spo11-induced lesions, 34 to several hundred base pair-long gaps, which are generated by coordinated pairs of DSBs termed double DSBs. Isolation and genome-wide mapping of the resulting fragments with single base-pair precision revealed enrichment at DSB hotspots but also a widely dispersed distribution across the genome. Spo11 prefers to cut sequences with similarity to a DNA-bending motif2, which indicates that bendability contributes to the choice of cleavage site. Moreover, fragment lengths have a periodicity of approximately (10.4n + 3) base pairs, which indicates that Spo11 favours cleavage on the same face of underwound DNA. Consistently, double DSB signals overlap and correlate with topoisomerase II-binding sites, which points to a role for topological stress and DNA crossings in break formation, and suggests a model for the formation of DSBs and double DSBs in which Spo11 traps two DNA strands. Double DSB gaps, which make up an estimated 20% of all initiation events, can account for full gene conversion events that are independent of both Msh2-dependent heteroduplex repair3,4 and the MutLγ endonuclease4. Because non-homologous gap repair results in deletions, and ectopically re-integrated double DSB fragments result in insertions, the formation of double DSBs is a potential source of evolutionary diversity and pathogenic germline aberrations. Meiotic recombination in yeast is not only initiated by single break sites, but also caused by closely spaced Spo11-dependent double-stranded DNA breaks that create chromosomal gaps.
Silvia Prieler; Doris Chen; Lingzhi Huang; Elisa Mayrhofer; Soma Zsótér; Magdalena Vesely; Jean Mbogning; Franz Klein. Spo11 generates gaps through concerted cuts at sites of topological stress. Nature 2021, 594, 577 -582.
AMA StyleSilvia Prieler, Doris Chen, Lingzhi Huang, Elisa Mayrhofer, Soma Zsótér, Magdalena Vesely, Jean Mbogning, Franz Klein. Spo11 generates gaps through concerted cuts at sites of topological stress. Nature. 2021; 594 (7864):577-582.
Chicago/Turabian StyleSilvia Prieler; Doris Chen; Lingzhi Huang; Elisa Mayrhofer; Soma Zsótér; Magdalena Vesely; Jean Mbogning; Franz Klein. 2021. "Spo11 generates gaps through concerted cuts at sites of topological stress." Nature 594, no. 7864: 577-582.
A major challenge in the safety assessment of food contact materials (FCM) is the evaluation of unknown non-intentionally added substances (NIAS). Even though consumer exposure levels may be quantitatively low, these substances are considered to be of high toxicological concern if they act as DNA reactive mutagens. From a safety assessment perspective, it is therefore important to detect their presence in FCM migrates. The present study applied the Ames MPF assay to assess the mutagenicity of migrates obtained from 30 food contact material samples out of 3 categories: plastics, composite materials and coatings. As a food simulant, 95% ethanol (EtOH) had a superior performance to less volatile simulants when evaluating recovery rates of representative model substances in different volatility categories. To monitor possible interference of the FCM matrix with Ames MPF results, migrates were spiked with reference substances and recovery rates were established. Out of 30 samples tested, two caused significant inhibition of revertant formation in the presence of the spiking control. Overall detection limits of the applied test method were estimated by determination of the lowest effective concentrations (LEC) for 10 Ames-positive substances. Even though the current limits of detection are not sufficient to entirely fulfil regulatory and safety requirements, three out of 30 FCMs showed evidence of dose-dependent effects in the Ames MPF assay. Overall, the data obtained supported the relevance of testing FCM migrates for DNA reactive contaminants and showed the value of the Ames MPF assay for the safety assessment of FCMs.
Bernhard Rainer; Elisa Mayrhofer; Miriam Redl; Irene Dolak; Daniela Mislivececk; Thomas Czerny; Christian Kirchnawy; Maricel Marin-Kuan; Benoît Schilter; Manfred Tacker. Mutagenicity assessment of food contact material migrates with the Ames MPF assay. Food Additives & Contaminants: Part A 2019, 36, 1419 -1432.
AMA StyleBernhard Rainer, Elisa Mayrhofer, Miriam Redl, Irene Dolak, Daniela Mislivececk, Thomas Czerny, Christian Kirchnawy, Maricel Marin-Kuan, Benoît Schilter, Manfred Tacker. Mutagenicity assessment of food contact material migrates with the Ames MPF assay. Food Additives & Contaminants: Part A. 2019; 36 (9):1419-1432.
Chicago/Turabian StyleBernhard Rainer; Elisa Mayrhofer; Miriam Redl; Irene Dolak; Daniela Mislivececk; Thomas Czerny; Christian Kirchnawy; Maricel Marin-Kuan; Benoît Schilter; Manfred Tacker. 2019. "Mutagenicity assessment of food contact material migrates with the Ames MPF assay." Food Additives & Contaminants: Part A 36, no. 9: 1419-1432.
Alternative splicing and adenosine to inosine (A to I) RNA-editing are major factors leading to co- and post-transcriptional modification of genetic information. Both, A to I editing and splicing occur in the nucleus. As editing sites are frequently defined by exon–intron basepairing, mRNA splicing efficiency should affect editing levels. Moreover, splicing rates affect nuclear retention and will therefore also influence the exposure of pre-mRNAs to the editing-competent nuclear environment. Here, we systematically test the influence of splice rates on RNA-editing using reporter genes but also endogenous substrates. We demonstrate for the first time that the extent of editing is controlled by splicing kinetics when editing is guided by intronic elements. In contrast, editing sites that are exclusively defined by exonic structures are almost unaffected by the splicing efficiency of nearby introns. In addition, we show that editing levels in pre- and mature mRNAs do not match. This phenomenon can in part be explained by the editing state of an RNA influencing its splicing rate but also by the binding of the editing enzyme ADAR that interferes with splicing.
Konstantin Licht; Utkarsh Kapoor; Elisa Mayrhofer; Michael F. Jantsch. Adenosine to Inosine editing frequency controlled by splicing efficiency. Nucleic Acids Research 2016, 44, 6398 -6408.
AMA StyleKonstantin Licht, Utkarsh Kapoor, Elisa Mayrhofer, Michael F. Jantsch. Adenosine to Inosine editing frequency controlled by splicing efficiency. Nucleic Acids Research. 2016; 44 (13):6398-6408.
Chicago/Turabian StyleKonstantin Licht; Utkarsh Kapoor; Elisa Mayrhofer; Michael F. Jantsch. 2016. "Adenosine to Inosine editing frequency controlled by splicing efficiency." Nucleic Acids Research 44, no. 13: 6398-6408.