TY - JOUR A1 - Reimann, Hauke A1 - Stopper, Helga A1 - Hintzsche, Henning T1 - Long-term fate of etoposide-induced micronuclei and micronucleated cells in Hela-H2B-GFP cells JF - Archives of Toxicology N2 - Micronuclei are small nuclear cellular structures containing whole chromosomes or chromosomal fragments. While there is a lot of information available about the origin and formation of micronuclei, less is known about the fate of micronuclei and micronucleated cells. Possible fates include extrusion, degradation, reincorporation and persistence. Live cell imaging was performed to quantitatively analyse the fates of micronuclei and micronucleated cells occurring in vitro. Imaging was conducted for up to 96 h in HeLa-H2B-GFP cells treated with 0.5, 1 and 2 µg/ml etoposide. While a minority of micronuclei was reincorporated into the main nucleus during mitosis, the majority of micronuclei persisted without any alterations. Degradation and extrusion were observed rarely or never. The presence of micronuclei affected the proliferation of the daughter cells and also had an influence on cell death rates. Mitotic errors were found to be clearly increased in micronucleus-containing cells. The results show that micronuclei and micronucleated cells can, although delayed in cell cycle, sustain for multiple divisions. KW - micronuclei KW - cell fate KW - etoposide KW - live imaging KW - DNA damage Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235039 SN - 0340-5761 VL - 94 ER - TY - THES A1 - Seier, Kerstin T1 - Investigation of dynamic processes of prototypical class A GPCRs by single-molecule microscopy T1 - Untersuchung von dynamischen Prozessen von prototypischen Klasse A GPCR's durch Einzelmolekülmikroskopie N2 - In this work, two projects were pursued. In the first project, I investigated two different subtypes of opioid receptors, which play a key role as target for analgesia. A set of subtype specific fluorescent ligands for μ opioid receptor (MOR) and δ opioid receptor (DOR) was characterised and used to gain insights into the diffusion behaviour of those receptors. It was shown that the novel ligands hold photophysical and pharmacological properties making them suitable for single-molecule microscopy. Applying them to wild-type receptors expressed in living cells revealed that both sub-types possess a heterogeneous diffusion behaviour. Further- more, the fluorescent ligands for the MOR were used to investigate homodomerisation, a highly debated topic. The results reveal that only ≈ 5 % of the receptors are present as homodimers, and thus the majority is monomeric. G-protein coupled receptors (GPCRs) play a major role as drug targets. Accordingly, understanding the activation process is very important. For a long time GPCRs have been believed to be either active or inactive. In recent years several studies have shown, that the reality is more complex, involving more substates. [1, 2, 3, 4] In this work the α 2A AR was chosen to investigate the activation process on a single-molecule level, thus being able to distinguish also rare or short-lived events that are hidden in ensemble mea- surements. With this aim, the receptor was labelled intracellular with two fluorophores using supported membranes. Thus it was possible to acquire movies showing qualita- tively smFRET events. Unfortunately, the functionality of the used construct could not be demonstrated. To recover the functionality the CLIP-tag in the third intracellular loop was replaced successfully with an amber codon. This stop codon was used to insert an unnatural amino acid. Five different mutants were created and tested and the most promising candidate could be identified. First ensemble FRET measurements indicated that the functionality might be recovered but further improvements would be needed. Overall, I could show that single-molecule microscopy is a versatile tool to investigate the behaviour of typical class A GPCRs. I was able to show that MOR are mostly monomeric under physiological expression levels. Furthermore, I could establish intra- cellular labelling with supported membranes and acquire qualitative smFRET events. N2 - In dieser Arbeit wurden zwei Projekte verfolgt. Im ersten Projekt wurden zwei Subtypen der Opioidrezeptoren untersucht, die eine wichtige Rolle für die Wirksamkeit von Analgetika spielen. Ein Set von subtypspezifischen fluoreszierenden Liganden für den MOR und den DOR wurde charakterisiert und eingesetzt, um Einblicke in das Diffuionsverhalten der Rezeptoren zu gewinnen. Es konnte gezeigt werden, dass die neuartigen Liganden sowohl photophysikalische als auch pharmakologische Eigenschaften besitzen, die sie für die Einzelmolekülmikroskopie interessant machen. Versuche mit Opioidrezeptoren, die in lebenden Zellen exprimiert werden, zeigten, dass beide Subtypen heterogenes Diffuionsverhalten aufweisen. Des Weiteren wurden die fluoreszierenden Liganden für den MOR genutzt um Homodimerisierung zu untersuchen, da dies ein kontrovers diskutiertes Thema ist. Die Ergebnisse zeigen, dass lediglich ≈ 5% der Rezeptoren als Homodimere vorliegen und der Großteil monomerisch ist. GPCRs sind besonderem Interesse, weil sie Angriffspunkt vieler Medikamente sind. Deshalb ist es wichtig ihren Aktivierungsmechanismus besser zu verstehen. Lange Zeit wurde angenommen, dass GPCRs entweder aktiv oder inaktiv sind. Neuere Studien zeigten jedoch, dass die Realität komplexer ist und der Prozess Zwischenschritte involviert. [1, 2, 3, 4] In dieser Arbeit wurde der α 2A Adrenorezeptor als prototypischer Klasse A GPCR gewählt, um den Aktivierungsprozess auf Einzelmoleküllevel zu untersuchen. Durch die Betrachtung einzelner Rezeptoren ist es möglich auch seltene oder sehr kurzlebige Ereignisse zu unterscheiden, die in Kollektivmessungen untergehen. Um dies zu erreichen wurde der Rezeptor erfolgreich intrazellulär mit zwei Fluorophoren markiert. Dies gelang durch die Herstellung von „supported membranes", also Zellmembranen die auf einem Objektträger fixiert wurden. Dadurch war es möglich Videos aufzunehmen, die Einzelmolekül-FRET-Ereignisse zeigen. Jedoch gelang es nicht zu zeigen, dass der Rezeptor als Ganzes noch funktional war. Um einen funktionalen Rezeptor zu erhalten, wurde das CLIP-Tag in der dritten intrazellulären Schleife erfolgreich durch ein Stopcodon ersetzt, welches für eine nicht kanonische Aminosäure kodierte. Fünf verschiedene Mutanten wurden kloniert und getestet, wobei der vielversprechendste Mutant identifiziert werden konnte. Erste FRET-Kollektivmessungen deuten darauf hin, dass dieser Mutant funktional sein könnte. Jedoch sind weitere Verbesserungen nötig. Insgesamt konnte ich zeigen, dass Einzelmolekülmikroskopie vielseitige Möglichkeiten bietet um das Verhalten von GPCRs zu untersuchen. Ich konnte nachweisen, dass MOR unter physiologischen Bedingungen hauptsächlich als Monomere vorliegen. Des Weiteren konnte ich Dank supported membranes die Markierung durch Farbstoffe im Intrazellularbereich etablieren und qualitative smFRET Ereignisse aufnehmen. KW - PhD thesis pharmacology KW - GPCR dimerisation KW - single-molecule imaging KW - opioid receptor Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-199739 ER - TY - JOUR A1 - Bankoglu, Ezgi Eyluel A1 - Schuele, Carolin A1 - Stopper, Helga T1 - Cell survival after DNA damage in the comet assay JF - Archives of Toxicology N2 - The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H\(_{2}\)O\(_{2}\)) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H\(_{2}\)O\(_{2}\) or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided. KW - Cell death and comet assay KW - DNA damage KW - DNA repair Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265339 VL - 95 IS - 12 ER - TY - JOUR A1 - Jeanclos, Elisabeth A1 - Knobloch, Gunnar A1 - Hoffmann, Axel A1 - Fedorchenko, Oleg A1 - Odersky, Andrea A1 - Lamprecht, Anna‐Karina A1 - Schindelin, Hermann A1 - Gohla, Antje T1 - Ca\(^{2+}\) functions as a molecular switch that controls the mutually exclusive complex formation of pyridoxal phosphatase with CIB1 or calmodulin JF - FEBS Letters N2 - Pyridoxal 5′‐phosphate (PLP) is an essential cofactor for neurotransmitter metabolism. Pyridoxal phosphatase (PDXP) deficiency in mice increases PLP and γ‐aminobutyric acid levels in the brain, yet how PDXP is regulated is unclear. Here, we identify the Ca\(^{2+}\)‐ and integrin‐binding protein 1 (CIB1) as a PDXP interactor by yeast two‐hybrid screening and find a calmodulin (CaM)‐binding motif that overlaps with the PDXP‐CIB1 interaction site. Pulldown and crosslinking assays with purified proteins demonstrate that PDXP directly binds to CIB1 or CaM. CIB1 or CaM does not alter PDXP phosphatase activity. However, elevated Ca\(^{2+}\) concentrations promote CaM binding and, thereby, diminish CIB1 binding to PDXP, as both interactors bind in a mutually exclusive way. Hence, the PDXP‐CIB1 complex may functionally differ from the PDXP‐Ca\(^{2+}\)‐CaM complex. KW - calmodulin KW - chronophin KW - CIB1 KW - haloacid dehalogenase KW - pyridoxal phosphatase KW - vitamin B6 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217963 VL - 594 IS - 13 SP - 2099 EP - 2115 ER - TY - JOUR A1 - Adaku Chilaka, Cynthia A1 - Mally, Angela T1 - Mycotoxin Occurrence, Exposure and Health Implications in Infants and Young Children in Sub-Saharan Africa: A Review JF - Foods N2 - Infants and young children (IYC) remain the most vulnerable population group to environmental hazards worldwide, especially in economically developing regions such as sub-Saharan Africa (SSA). As a result, several governmental and non-governmental institutions including health, environmental and food safety networks and researchers have been proactive toward protecting this group. Mycotoxins, toxic secondary fungal metabolites, contribute largely to the health risks of this young population. In SSA, the scenario is worsened by socioeconomic status, poor agricultural and storage practices, and low level of awareness, as well as the non-establishment and lack of enforcement of regulatory limits in the region. Studies have revealed mycotoxin occurrence in breast milk and other weaning foods. Of concern is the early exposure of infants to mycotoxins through transplacental transfer and breast milk as a consequence of maternal exposure, which may result in adverse health effects. The current paper presents an overview of mycotoxin occurrence in foods intended for IYC in SSA. It discusses the imperative evidence of mycotoxin exposure of this population group in SSA, taking into account consumption data and the occurrence of mycotoxins in food, as well as biomonitoring approaches. Additionally, it discusses the health implications associated with IYC exposure to mycotoxins in SSA. KW - mycotoxin KW - occurrence KW - exposure KW - child health KW - sub-Saharan Africa Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219250 SN - 2304-8158 VL - 9 IS - 11 ER - TY - THES A1 - Bertelsmann, Dietmar T1 - Analysis of the Frequency of Kidney Toxicity in Preclinical Safety Studies using the eTOX Database T1 - Analyse der Häufigkeit von Nierentoxizität in präklinischen Sicherheitsstudien unter Verwendung der eTOX-Datenbank N2 - This research aimed to obtain reliable data on the frequency of different types of renal toxicity findings in 28-day oral gavage studies in Wistar rats, their consistency across species and study duration, as well as the correlation between histopathological endpoints and routinely used clinical chemistry parameters indicative of kidney injury. Analysis of renal histopathological findings was carried out through extraction of information from the IMI eTOX database. Spontaneous renal histopathological findings in 28-day oral gavage studies in control Wistar rats and beagle dogs confirmed tubular basophilia and renal dilation as the most frequent incidental findings in controls, whereas necrosis and glomerulosclerosis were not identified at all or only rarely as a background lesion. Histopathological evidence of necrosis and glomerulosclerosis was associated with changes in clinical chemistry parameters in 28-day oral gavage Wistar rat studies. Necrosis was frequently accompanied by a statistically significant rise in serum creatinine and serum urea, whereas serum albumin was frequently found to decrease statistically significantly in treatment groups in which necrosis was recorded. In contrast to necrosis, glomerulosclerosis was not associated with statistically significant changes in serum creatinine and urea in any of the 28-day oral gavage Wistar rat treatment groups, but appears to be best reflected by a pattern of statistically significantly lowered serum albumin and serum protein together with a statistically significant increase in serum cholesterol. As might have been expected based on the high background incidences of tubular basophilia and dilation, no consistent changes in any of the clinical chemistry parameters were evident in animals in which renal lesions were con� fined to renal tubular basophilia or dilation. In summary, the routinely provided clinical chemistry parameters are rather insensitive - novel kidney biomarkers such as Cystatin C, β-trace protein and Kidney injury molecule 1 should further be evaluated and integrated into routine preclinical and clinical practice. However, evaluation of clinical chemistry data was limited by the lack of individual animal data. Even though an extensive amount of preclinical studies is accessible through the eTOX database, comparison of consistency across time was limited by the limited number of shorter- and longer term studies conducted with the compounds identified as causing renal histopathological changes within a 28- day study in rats. A high consistency across time for both treatment-related tubular basophilia and treatment-related dilation cannot be confirmed for either of the two effects as these two findings were both induced only rarely in studies over a different treatment-duration other than 28 days after administration of the compounds which provoked the respective effect in a 28-day study. For the finding of necrosis consistency across time was low with the exception of “AZ_GGA_200002321”, in which renal papillary necrosis was identified consist� ently throughout different treatment durations (2, 4, 26, 104 weeks). No shorter and longer-term studies were available for the compounds identified as causing glomerulosclerosis within a 28-day study in rats. No consistent findings of the selected histopathological endpoints were identified in any of the corresponding 28-day oral gavage beagle dog studies after treatment with the identical compounds, which caused the respective ef� fect after 28-day treatment in rats. However, in the overwhelming majority of cases, beagle dogs were administered lower doses in these studies in compar� ison to the corresponding 28-day Wistar rat studies. Searching the eTOX database yielded no 28-day oral gavage studies in Wistar and Wistar Han rats in which accumulation of hyaline droplets, tubular atrophy or hyperplasia was recorded. Only one 28-day oral gavage Wistar rat study was identified with the histopathological result of neutrophilic inflammation. Consequently, evaluation of these four renal findings in relation to clinical chemistry parameters and consistency across time and species cannot be made. In summary, this work contributes knowledge through mining and evaluating the eTOX database on a variety of specific renal endpoints that frequently occur after administration of trial substances in 28-day oral gavage studies in Wistar rats in the field of preclinical toxicity with specific focus on their frequency relation to background findings, as well as consistency across time and species. Targeted statistical evaluation of in vivo data within joint research ventures such as the eTOX project, presents an enormous opportunity for an innovative future way of aiding preclinical research towards a more efficient research in the preclinical stage of drug development. This could be achieved through the aug� mentation of methodological strategies and possibly novel software tools in order to predict in vivo toxicology of new molecular entities by means of information that is already available before early stages of the drug development pipeline begin. N2 - Diese Arbeit zielte darauf ab, verlässliche Daten über die Häufigkeit verschiedener Arten von Nierentoxizitätsbefunden in 28-tägigen oralen Sondenstudien an Wistar-Ratten zu erhalten. Untersucht wurde weiterhin die Konsistenz der Toxizitätsbefunde unterschiedlicher Spezies und Studiendauer sowie die Korrelation zwischen histopathologischen Endpunkten und routinemäßig verwendeten klinisch-chemischen Parametern, die auf eine Nierenschädigung hinweisen. Die Analyse der histopathologischen Nierenbefunde wurde durch Extraktion von Informationen aus der IMI eTOX-Datenbank durchgeführt. Spontane renale histopathologische Befunde in 28-tägigen oralen Sondenstudien an Wistar-Ratten und Beagles bestätigten tubuläre Basophilie und renale Dilatation als häufigste Nebenbefunde bei den Kontrolltieren, während Nekrose und Glomerulosklerose gar nicht oder nur selten als Hintergrundläsion identifiziert wurden. Der histopathologische Nachweis von Nekrose und Glomerulosklerose war mit Änderungen der klinisch-chemischen Parameter in 28-tägigen Wistar-Rattenstudien mit oraler Sonde verbunden. Nekrose ging häufig mit einem statistisch signifikanten Anstieg von Serumkreatinin und Serumharnstoff einher, während Serumalbumin in Behandlungsgruppen, in denen Nekrose aufgezeichnet wurde, häufig statistisch signifikant abnahm. Im Gegensatz zur Nekrose war Glomerulosklerose in keiner der 28-tägigen Wistar-Ratten-Behandlungsgruppen mit oraler Sonde mit statistisch signifikanten Veränderungen von Serumkreatinin und Harnstoff assoziiert, sondern scheint sich am besten in einem Muster von statistisch signifikant erniedrigtem Serumalbumin und Serumprotein zusammen mit einem statistisch signifikanten Anstieg des Serumcholesterins widerzuspiegeln. Wie aufgrund der hohen Hintergrundinzidenzen von tubulärer Basophilie und Dilatation zu erwarten war, waren bei Tieren, bei denen Nierenläsionen auf renale tubuläre Basophilie oder Dilatation beschränkt waren, keine konsistenten Änderungen der klinisch-chemischen Parameter erkennbar. Zusammenfassend sind die routinemäßig bereitgestellten klinisch-chemischen Parameter eher unempfindlich - neuartige Nieren-Biomarker wie „Cystatin C“, „β-trace protein“ und „Kidney injury molecule 1“ sollten weiter evaluiert und in die routinemäßige präklinische und klinische Praxis integriert werden. Die Auswertung der Daten zur klinischen Chemie war jedoch durch das Fehlen individueller Tierdaten begrenzt. Trotz der umfangreichen Anzahl an präklinischen Studien in der eTOX-Datenbank wurde der zeitliche Vergleich der Konsistenz durch die begrenzte Anzahl von Kurz- und Langzeitstudien eingeschränkt, welche mit denselben Substanzen durchgeführt wurden, die innerhalb einer 28-Tage-Studie an Ratten als Verursacher von renalen histopathologischen Veränderungen identifiziert wurden. Eine hohe zeitliche Konsistenz sowohl für die behandlungsbedingte tubuläre Basophilie und Dilatation kann für keinen der beiden Effekte bestätigt werden, da diese beiden Befunde nur selten in Studien über eine andere Behandlungsdauer als 28 Tage nach Verabreichung derselben Substanzen, die den jeweiligen Effekt in einer 28-Tage-Studie hervorriefen, induziert wurden. Für den Befund der Nekrose war die zeitliche Konsistenz gering. Eine Ausnahme stellte Substanz "AZ_GGA_200002321" dar, bei der über verschiedene Behandlungsdauern (2, 4, 26, 104 Wochen) hinweg konstant renale papilläre Nekrose festgestellt wurde. Für die Substanzen, die in einer 28-Tage-Studie an Ratten als glomeruloskleroseauslösend identifiziert wurden, waren keine Kurz- und Langzeitstudien verfügbar. In keiner der korrespondierenden 28-Tage-Studien an Beagles mit oraler Sonde wurden konsistente Befunde der ausgewählten histopathologischen Endpunkte nach Behandlung mit den identischen Verbindungen, die den jeweiligen Effekt nach 28-tägiger Behandlung in Ratten verursachten, festgestellt. In der überwiegenden Mehrheit der Fälle wurden den Beagles in diesen Studien im Vergleich zu den entsprechenden 28-Tage-Wistar-Rattenstudien niedrigere Dosen verabreicht. In der eTOX-Datenbank konnten keine 28-tägigen oralen Sondenstudien an Wistar- und Wistar-Han-Ratten gefunden werden, in denen eine Akkumulation von hyalinen Tröpfchen, tubuläre Atrophie oder Hyperplasie aufgezeichet wurde. Nur eine 28-tägige Wistar-Rattenstudie wurde mit dem histopathologischen Ergebnis einer neutrophilen Entzündung identifiziert. Folglich kann eine Bewertung dieser vier Nierenbefunde in Bezug auf klinische Chemie und Konsistenz über Zeit und Spezies nicht vorgenommen werden. Insgesamt zeigt dieser Arbeit, dass eine gezielte statistische Auswertung von in vivo-Daten im Rahmen von Forschungsverbünden wie dem eTOX-Projekt eine enorme Chance bietet, die präklinische Forschung in Zukunft auf dem Weg zu einer effizienteren Forschung in der präklinischen Phase der Arzneimittelentwicklung zu unterstützen. Dies könnte außerdem durch die Erweiterung methodischer Strategien und möglicherweise neuartiger Software-Tools erreicht werden, um die In-vivo-Toxikologie neuer molekularer Entitäten mit Hilfe von Informationen vorherzusagen, die bereits vor Beginn der Arzneimittelentwicklungspipeline verfügbar sind. KW - renal toxicity KW - etox database KW - rats KW - toxicity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257104 ER - TY - JOUR A1 - Hintzsche, Henning A1 - Montag, Gracia A1 - Stopper, Helga T1 - Induction of micronuclei by four cytostatic compounds in human hematopoietic stem cells and human lymphoblastoid TK6 cells JF - Scientific Reports N2 - For mutagenicity testing, primary lymphocytes or mammalian cell lines are employed. However, the true target for carcinogenic action of mutagenic chemicals may be stem cells. Since hematopoietic cancers induced by chemical agents originate at the hematopoietic stem cell (HSC) stage and since one of the side effects of chemotherapeutic cancer treatment is the induction of secondary tumors, often leukemias, HSC may be a suitable cell system. We compared the sensitivity of HSC with the genotoxicity testing cell line TK6 for chromosomal mutations. HSC were less sensitive than TK6 cells for the genotoxic effects of the model genotoxins and chemotherapeutic agents doxorubicin, vinblastine, methyl methanesulfonate (MMS) and equally sensitive for mitomycin C (MMC). However, loss of viability after mitomycin C treatment was higher in HSC than in TK6 cells. Among the factors that may influence sensitivity for genomic damage, the generation or response to reactive oxygen species (ROS) and the effectiveness of DNA damage response can be discussed. Here we show that HSC can be used in a standard micronucleus test protocol for chromosomal mutations and that their sensitivity was not higher than that of a classical testing cell line. KW - apoptosis KW - haematopoietic stem cells KW - TK6 cells KW - micronuclei Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176210 VL - 8 IS - 3371 ER - TY - JOUR A1 - Chilaka, Cynthia Adaku A1 - Obidiegwu, Jude Ejikeme A1 - Chilaka, Augusta Chinenye A1 - Atanda, Olusegun Oladimeji A1 - Mally, Angela T1 - Mycotoxin regulatory status in Africa: a decade of weak institutional efforts JF - Toxins N2 - Food safety problems are a major hindrance to achieving food security, trade, and healthy living in Africa. Fungi and their secondary metabolites, known as mycotoxins, represent an important concern in this regard. Attempts such as agricultural, storage, and processing practices, and creation of awareness to tackle the menace of fungi and mycotoxins have yielded measurable outcomes especially in developed countries, where there are comprehensive mycotoxin legislations and enforcement schemes. Conversely, most African countries do not have mycotoxin regulatory limits and even when available, are only applied for international trade. Factors such as food insecurity, public ignorance, climate change, poor infrastructure, poor research funding, incorrect prioritization of resources, and nonchalant attitudes that exist among governmental organisations and other stakeholders further complicate the situation. In the present review, we discuss the status of mycotoxin regulation in Africa, with emphasis on the impact of weak mycotoxin legislations and enforcement on African trade, agriculture, and health. Furthermore, we discuss the factors limiting the establishment and control of mycotoxins in the region. KW - fungi KW - mycotoxin KW - legislation KW - food safety KW - food security Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278941 SN - 2072-6651 VL - 14 IS - 7 ER - TY - JOUR A1 - Winkelbeiner, Nicola A1 - Wandt, Viktoria K. A1 - Ebert, Franziska A1 - Lossow, Kristina A1 - Bankoglu, Ezgi E. A1 - Martin, Maximilian A1 - Mangerich, Aswin A1 - Stopper, Helga A1 - Bornhorst, Julia A1 - Kipp, Anna P. A1 - Schwerdtle, Tanja T1 - A multi-endpoint approach to base excision repair incision activity augmented by PARylation and DNA damage levels in mice: impact of sex and age JF - International Journal of Molecular Sciences N2 - Investigation of processes that contribute to the maintenance of genomic stability is one crucial factor in the attempt to understand mechanisms that facilitate ageing. The DNA damage response (DDR) and DNA repair mechanisms are crucial to safeguard the integrity of DNA and to prevent accumulation of persistent DNA damage. Among them, base excision repair (BER) plays a decisive role. BER is the major repair pathway for small oxidative base modifications and apurinic/apyrimidinic (AP) sites. We established a highly sensitive non-radioactive assay to measure BER incision activity in murine liver samples. Incision activity can be assessed towards the three DNA lesions 8-oxo-2'-deoxyguanosine (8-oxodG), 5-hydroxy-2'-deoxyuracil (5-OHdU), and an AP site analogue. We applied the established assay to murine livers of adult and old mice of both sexes. Furthermore, poly(ADP-ribosyl)ation (PARylation) was assessed, which is an important determinant in DDR and BER. Additionally, DNA damage levels were measured to examine the overall damage levels. No impact of ageing on the investigated endpoints in liver tissue were found. However, animal sex seems to be a significant impact factor, as evident by sex-dependent alterations in all endpoints investigated. Moreover, our results revealed interrelationships between the investigated endpoints indicative for the synergetic mode of action of the cellular DNA integrity maintaining machinery. KW - maintenance of genomic integrity KW - ageing KW - sex KW - DNA damage KW - base excision repair (incision activity) KW - DNA damage response KW - poly(ADP-ribosyl)ation KW - liver Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285706 SN - 1422-0067 VL - 21 IS - 18 ER - TY - JOUR A1 - Tolstik, Elen A1 - Ali, Nairveen A1 - Guo, Shuxia A1 - Ebersbach, Paul A1 - Möllmann, Dorothe A1 - Arias-Loza, Paula A1 - Dierks, Johann A1 - Schuler, Irina A1 - Freier, Erik A1 - Debus, Jörg A1 - Baba, Hideo A. A1 - Nordbeck, Peter A1 - Bocklitz, Thomas A1 - Lorenz, Kristina T1 - CARS imaging advances early diagnosis of cardiac manifestation of Fabry disease JF - International Journal of Molecular Sciences N2 - Vibrational spectroscopy can detect characteristic biomolecular signatures and thus has the potential to support diagnostics. Fabry disease (FD) is a lipid disorder disease that leads to accumulations of globotriaosylceramide in different organs, including the heart, which is particularly critical for the patient’s prognosis. Effective treatment options are available if initiated at early disease stages, but many patients are late- or under-diagnosed. Since Coherent anti-Stokes Raman (CARS) imaging has a high sensitivity for lipid/protein shifts, we applied CARS as a diagnostic tool to assess cardiac FD manifestation in an FD mouse model. CARS measurements combined with multivariate data analysis, including image preprocessing followed by image clustering and data-driven modeling, allowed for differentiation between FD and control groups. Indeed, CARS identified shifts of lipid/protein content between the two groups in cardiac tissue visually and by subsequent automated bioinformatic discrimination with a mean sensitivity of 90–96%. Of note, this genotype differentiation was successful at a very early time point during disease development when only kidneys are visibly affected by globotriaosylceramide depositions. Altogether, the sensitivity of CARS combined with multivariate analysis allows reliable diagnostic support of early FD organ manifestation and may thus improve diagnosis, prognosis, and possibly therapeutic monitoring of FD. KW - coherent anti-Stokes Raman scattering (CARS) microscopy KW - Raman micro-spectroscopy KW - cardiovascular diseases KW - Fabry Disease (FD) KW - Gb3 and lyso-Gb3 biomarkers KW - multivariate data analysis KW - immunohistochemistry Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284427 SN - 1422-0067 VL - 23 IS - 10 ER -