55 research outputs found
Regulated mitochondrial DNA replication during oocyte maturation is essential for successful porcine embryonic development.
Cellular ATP is mainly generated through mitochondrial oxidative phosphorylation, which is dependent on mitochondrial DNA (mtDNA). We have previously demonstrated the importance of oocyte mtDNA for porcine and human fertilization. However, the role of nuclear-encoded mitochondrial replication factors during oocyte and embryo development is not yet understood. We have analyzed two key factors, mitochondrial transcription factor A (TFAM) and polymerase gamma (POLG), to determine their role in oocyte and early embryo development. Competent and incompetent oocytes, as determined by brilliant cresyl blue (BCB) dye, were assessed intermittently during the maturation process for TFAM and POLG mRNA using real-time RT-PCR, for TFAM and POLG protein using immunocytochemistry, and for mtDNA copy number using real-time PCR. Analysis was also carried out following treatment of maturing oocytes with the mtDNA replication inhibitor, 2',3'-dideoxycytidine (ddC). Following in vitro fertilization, preimplantation embryos were also analyzed. Despite increased levels of TFAM and POLG mRNA and protein at the four-cell stage, no increase in mtDNA copy number was observed in early preimplantation development. To compensate for this, mtDNA appeared to be replicated during oocyte maturation. However, significant differences in nuclear-encoded regulatory protein expression were observed between BCB(+) and BCB(-) oocytes and between untreated oocytes and those treated with ddC. These changes resulted in delayed mtDNA replication, which correlated to reduced fertilization and embryonic development. We therefore conclude that adherence to the regulation of the timing of mtDNA replication during oocyte maturation is essential for successful embryonic development
Risk assessment of chlorinated paraffins in feed and food
The Panel wishes to thank the hearing expert: Kerstin KrÀtschmer and EFSA staff member: Kelly Niermans for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data in food and human milk and data on the toxicity of CPs, and supported the data collection for the Comprehensive European Food Consumption Database.Peer reviewedPublisher PD
Risks for human health related to the presence of pyrrolizidine alkaloids in honey, tea, herbal infusions and food supplements
The Panel wishes to acknowledge all European competent institutions, Member State bodies and other organisations that provided data for this scientific output. Adopted: 21 June 2017Peer reviewedPublisher PD
Assessment of a decontamination process for hydrocyanic acid in linseed intended for use in animal feed
Adopted: 19 September 2017Peer reviewedPublisher PD
Assessment of a decontamination process for dioxins and PCBs from fish meal by hexane extraction and replacement of fish oil
Adopted: 23 January 2018Peer reviewedPublisher PD
Scientific opinion on the evaluation of substances as acceptable previous cargoes for edible fats and oils
The Panel wishes to thank the members of the Working Group on acceptable previous cargoes for edible fats and oils â Previous cargoes 2016: Bettina Grasl-Kraupp, Konrad Grob, AndrĂ© Penninks and Christiane Vleminckx and EFSA staff members: Marco Binaglia and Ruth RoldĂĄn Torres. The Panel acknowledges the European Chemicals Agency that provided data on ammonium sulphate.Peer reviewedPublisher PD
Appropriateness to set a group health based guidance value for T2 and HT2 toxin and its modified forms
Acknowledgements: The Panel wishes to thank the members of the Working Group on HBGV for mycotoxins and their modified forms: Jan Alexander, Chiara Dall'Asta, Arno Gutleb, Manfred Metzler, Isabelle Oswald and Dominique Parent-Massin for the preparatory work on this scientific opinion, and the EFSA staff members: Marco Binaglia and Hans Steinkellner for the support provided to this scientific opinion.Peer reviewedPublisher PD
Appropriateness to set a group health based guidance value for nivalenol and its modified forms
The Panel wishes to thank the members of the Working Group on HBGV for mycotoxins and their modified forms: Jan Alexander, Chiara Dall'Asta, Arno Gutleb, Manfred Metzler, Isabelle P Oswald and Dominique ParentâMassin for the preparatory work on this scientific output, and the EFSA staff members: Marco Binaglia and Hans Steinkellner for the support provided to this scientific output. Adopted: 15 March 2017Peer reviewedPublisher PD
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