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Dive into the research topics where Dagmar Zeljenková is active.

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Featured researches published by Dagmar Zeljenková.


Interdisciplinary Toxicology | 2013

Acute toxicity of 31 different nanoparticles to zebrafish (Danio rerio) tested in adulthood and in early life stages – comparative study

Jevgenij A. Kovrižnych; Ružena Sotníková; Dagmar Zeljenková; Eva Rollerova; Elena Szabova; Soňa Wimmerová

Abstract At present, nanoparticles are beginning to influence our lives in many ways and understanding the environmental health and safety aspect of nanomaterials has become a crucial issue. The aim of the work was to assess and compare the acute toxicity of 31 different nanomaterials to fish mature individuals Danio rerio with that to fish early life stages on using evaluation of the 48- and 96- hour LC50 values. A further aim was to evaluate teratogenicity of the nanoparticles tested to fish eggs. The nanoparticles tested were: 8 pure metals, 10 metal oxides, 5 other metal compounds and their mixtures, 2 silicon compounds, 3 calcium compounds, and 3 carbon compounds. Using 48-h and 96-h tests of acute toxicity (according to OECD 203), we evaluated mortality data, LC50 values, occurrence of malformations, as well as hatching time. In our study, 6 kinds of nanoparticles - calcium oxide, copper, copper in the form of oxide and CuZnFe4O4, magnesium oxide, and nickel - caused cumulative mortality. Two kinds of nanoparticles - copper and silver - were toxic for fish with LC50 values of approximately 3 mg/L. We did not observe marked differences between the 48-hour and 96-hour acute toxicity LC50 values, yet the possibility to evaluate hatching time in the 96-h acute fish toxicity test seems to be an advantage against that of the 48-hour toxicity.


Interdisciplinary Toxicology | 2014

Long-term (30 days) toxicity of NiO nanoparticles for adult zebrafish Danio rerio.

Jevgenij Kovrižnych; Ružena Sotníková; Dagmar Zeljenková; Eva Rollerova; Elena Szabova

Abstract Nickel oxide in the form of nanoparticles (NiO NPs) is extensively used in different industrial branches. In a test on adult zebrafish, the acute toxicity of NiO NPs was shown to be low, however longlasting contact with this compound can lead to its accumulation in the tissues and to increased toxicity. In this work we determined the 30-day toxicity of NiO NPs using a static test for zebrafish Danio rerio. We found the 30-day LC50 value to be 45.0 mg/L, LC100 (minimum concentration causing 100% mortality) was 100.0 mg/L, and LC0 (maximum concentration causing no mortality) was 6.25 mg/L for adult individuals of zebrafish. Considering a broad use of Ni in the industry, NiO NPs chronic toxicity may have a negative impact on the population of aquatic organisms and on food web dynamics in aquatic systems.


Archives of Toxicology | 2016

Proposed criteria for the evaluation of the scientific quality of mandatory rat and mouse feeding trials with whole food/feed derived from genetically modified plants

Kerstin Schmidt; Janine Döhring; Christian Kohl; Maria Pla; Esther J. Kok; Debora C. M. Glandorf; René Custers; Hilko van der Voet; Jutta Sharbati; Ralf Einspanier; Dagmar Zeljenková; Jana Tulinska; Armin Spök; Clare Alison; Dieter Schrenk; Annette Pöting; Ralf Wilhelm; Joachim Schiemann; Pablo Steinberg

In recent years, animal feeding trials conducted with whole food/feed have been a focal issue in the controversy on the safety assessment of genetically modified (GM) plants and derived food/feed. Within the scientific community and among stakeholders, quite different views have been expressed on how these studies should be conducted, analysed and interpreted, what they might add in terms of information relevant to safety and whether 90-day rodent feeding trials should be mandatory. Despite the fact that the Commission Implementing Regulation (EU) No. 503/2013 (specifying the requirements for the risk assessment of GM food/feed) requests mandatory 90-day feeding trials for GM plants with single transformation events, the controversy continues. This is due to the fact that in 2016 the European Commission will have to review this particular provision in the legislation (ibid, Article 12), and because of questions raised by long-term feeding studies with GM maize.


Frontiers in Genetics | 2017

Transcriptomic Analysis of Intestinal Tissues from Two 90-Day Feeding Studies in Rats Using Genetically Modified MON810 Maize Varieties

Jutta Sharbati; Marc Bohmer; Nils Bohmer; Andreas Keller; Christina Backes; Andre Franke; Pablo Steinberg; Dagmar Zeljenková; Ralf Einspanier

Background: Global as well as specific expression profiles of selected rat tissues were characterized to assess the safety of genetically modified (GM) maize MON810 containing the insecticidal protein Cry1Ab. Gene expression was evaluated by use of Next Generation Sequencing (NGS) as well as RT-qPCR within rat intestinal tissues based on mandatory 90-day rodent feeding studies. In parallel to two 90-day feeding studies, the transcriptional response of rat tissues was assessed as another endpoint to enhance the mechanistic interpretation of GM feeding studies and/or to facilitate the generation of a targeted hypothesis. Rats received diets containing 33% GM maize (MON810) or near-isogenic control maize. As a site of massive exposure to ingested feed the transcriptomic response of ileal and colonic tissue was profiled via RT-qPCR arrays targeting apoptosis, DNA-damage/repair, unfolded protein response (UPR). For global RNA profiling of rat ileal tissue, we applied NGS. Results: No biological response to the GM-diet was observed in male and in female rat tissues. Transcriptome wide analysis of gene expression by RNA-seq confirmed these findings. Nevertheless, gene ontology (GO) analysis clearly associated a set of distinctly regulated transcripts with circadian rhythms. We confirmed differential expression of circadian clock genes using RT-qPCR and immunoassays for selected factors, thereby indicating physiological effects caused by the time point of sampling. Conclusion: Prediction of potential unintended effects of GM-food/feed by transcriptome based profiling of intestinal tissue presents a novel approach to complement classical toxicological testing procedures. Including the detection of alterations in signaling pathways in toxicity testing procedures may enhance the confidence in outcomes of toxicological trials. In this study, no significant GM-related changes in intestinal expression profiles were found in rats fed GM-maize MON810. Relevant alterations of selected cellular pathways (apoptosis, DNA damage and repair, UPR) pointing toward intestinal toxicity of the diets were not observed. Transcriptomic profiles did not reveal perturbations of pathways associated with toxicity, underlining the study results revealed by classical OECD endpoints.


Archives of Toxicology | 2014

Ninety-day oral toxicity studies on two genetically modified maize MON810 varieties in Wistar Han RCC rats (EU 7th Framework Programme project GRACE)

Dagmar Zeljenková; Katarína Ambrušová; Mária Bartušová; Anton Kebis; Jevgenij Kovrižnych; Zora Krivošíková; Miroslava Kuricova; Aurelia Liskova; Eva Rollerova; Viera Spustová; Elena Szabova; Jana Tulinska; Soňa Wimmerová; Mikuláš Levkut; Viera Revajová; Zuzana Ševčíková; Kerstin Schmidt; Jörg Schmidtke; Jose Luis La Paz; Maria Corujo; Maria Pla; Gijs Kleter; Esther J. Kok; Jutta Sharbati; Carlos Hanisch; Ralf Einspanier; Karine Adel-Patient; Jean-Michel Wal; Armin Spök; Annette Pöting


Reproductive Toxicology | 2008

Polycyclic aromatic hydrocarbons and occupational risk factor

Elena Szabova; Dagmar Zeljenková; Eva Neščáková; Milan Šimko; Ladislav Turecký


Archives of Toxicology | 2016

One-year oral toxicity study on a genetically modified maize MON810 variety in Wistar Han RCC rats (EU 7th Framework Programme project GRACE).

Dagmar Zeljenková; Radka Aláčová; Júlia Ondrejková; Katarína Ambrušová; Mária Bartušová; Anton Kebis; Jevgenij Kovrižnych; Eva Rollerova; Elena Szabova; Soňa Wimmerová; Martin Cernak; Zora Krivošíková; Miroslava Kuricova; Aurelia Liskova; Viera Spustová; Jana Tulinska; Mikuláš Levkut; Viera Revajová; Zuzana Ševčíková; Kerstin Schmidt; Jörg Schmidtke; Paul Schmidt; Jose Luis La Paz; Maria Corujo; Maria Pla; Gijs Kleter; Esther J. Kok; Jutta Sharbati; Marc Bohmer; Nils Bohmer


Reproductive Toxicology | 2010

Cranio-facial anomalies in the Slovak Republic

Elena Szabova; Dagmar Zeljenková; Richard Molokáč; Jevgenij Kovrižnych; Eva Véghová; Daniela Brašeňová; Eva Neščáková; Agáta Molnárová; Jozef Fedeleš


Reproductive Toxicology | 2009

Anthropometric parameters of cases with oral clefts

Marta Cvíčelová; Magdaléna Nagyová; Agáta Molnárová; Jozef Fedeleš; Eva Bieliková; Elena Szabova; Dagmar Zeljenková; Jevgenij Kovrižnych


Reproductive Toxicology | 2007

Developmental effects of copper complexes

Dagmar Zeljenková; Elena Szabova; Milan Melník

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Elena Szabova

Slovak Medical University

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Jutta Sharbati

Free University of Berlin

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Eva Rollerova

Slovak Medical University

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Kerstin Schmidt

Dresden University of Technology

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Ralf Einspanier

Free University of Berlin

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Jana Tulinska

Slovak Medical University

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Esther J. Kok

Wageningen University and Research Centre

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