Publications by authors named "Ruth Appeltant"
Article Synopsis
- Wildlife biodiversity helps keep ecosystems healthy and strong.
- Scientists study this diversity to learn more about life and how it started.
- Due to the rapid loss of various species, immediate action is needed from conservationists, and new techniques like stem cell technologies could help protect animal diversity.
Article Synopsis
- Cloning in the animal kingdom involves creating genetically identical individuals and is gaining attention for its potential in conserving endangered or extinct species.
- Various reproductive techniques, including somatic cell nuclear transfer and induced pluripotent stem cells, expand our understanding of cloning's role in conservation beyond traditional methods.
- Ethical considerations and practical implications must be evaluated alongside biological advancements to assess the viability of cloning in protecting endangered species.
The northern white rhinoceros is functionally extinct with only two females left. Establishing methods to culture ovarian tissues, follicles, and oocytes to generate eggs will support conservation efforts using in vitro embryo production. To the best of our knowledge, this is the first description of the structure and molecular signature of any rhinoceros, more specifically, we describe the neonatal and adult southern white rhinoceros (Ceratotherium simum simum) ovary; the closest relation of the northern white rhinoceros.
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- - Cloning involves creating genetically identical individuals and has varied definitions over time, from natural reproduction in bacteria to advanced molecular techniques in vertebrates.
- - Key methods for mammalian cloning include embryo splitting, somatic cell nuclear transfer, and using induced pluripotent stem cells, with emerging biotechnologies enhancing genome propagation.
- - This review focuses on the current cloning technologies and their potential applications in conserving endangered animal species, moving beyond human and rodent research models.
Article Synopsis
- Mitochondrial quality declines with age, affecting female fertility, prompting a study on mitochondrial RNA transcripts in mouse oocytes and cumulus cells across different age groups.
- No significant age-related differences in mitochondrial transcripts were found, but variations were more frequent in cumulus cells compared to oocytes.
- The findings suggest either oocytes experience less post-transcriptional modification or they have a lower mtDNA mutational load compared to cumulus cells.
Article Synopsis
- * With extinction rates drastically higher than natural, conservation programs need support, and advanced reproductive technologies (ART and aART) combined with cryobanking (storing viable cells and tissues at very low temperatures) could be vital for preserving species.
- * For successful implementation, enhanced species-specific methods and better understanding of various organisms' biology are necessary, particularly for endangered species, including amphibians, to help slow down and potentially reverse biodiversity loss.
Article Synopsis
- Clinical mastitis (CM) in lactating cows is influenced by genetics, with a key resistance QTL found on chromosome 6 in various dairy breeds.
- Researchers identified a specific ~12 kb copy number variant (CNV) linked to this resistance, suggesting it affects the expression of the group-specific component gene (GC), which is related to vitamin D binding.
- The study indicates that the CNV not only contributes to CM resistance but is also linked to improved milk yield and lower fertility, hinting that vitamin D pathways play a significant role in these traits.
Article Synopsis
- - The mass extinction of animal species, driven largely by human actions like habitat destruction, is leading to a significant loss of biodiversity globally.
- - Traditional zoo breeding programs are evolving to incorporate assisted reproduction technologies (ART), including techniques like artificial insemination and in-vitro embryo generation, to help conserve endangered species.
- - Advanced ART methods, such as cloning and stem-cell techniques, are being developed to further support species preservation, utilizing cryopreservation and biobanking to maximize genetic diversity and improve the chances of restoring populations.
Article Synopsis
- Vitrification of porcine immature oocytes negatively impacts their development, prompting a study on how different factors affect their viability and growth after the process.
- Key factors tested included exposure time to the vitrification solution, the addition of macromolecules like BSA or PVP, cytochalasin B treatment, equilibration temperature, and two different vitrification methods (microdrop vs. Cryotop).
- Findings indicated that longer exposure to the vitrification solution harmed embryo development, while using PVP instead of BSA and the microdrop method enhanced survival rates, ultimately leading to a more effective cryopreservation system for these oocytes.
Article Synopsis
- Offspring can be produced from porcine oocytes that were vitrified at the germinal vesicle (GV) stage, but the success rate of embryo development is low.
- The study compared nuclear morphology, cumulus expansion, transzonal projections, and biochemical levels between vitrified cumulus-oocyte complexes (COCs) and control groups, discovering that vitrification causes premature nuclear maturation while cytoplasmic maturation remains mostly unaffected.
- Findings suggest that reduced embryo development could be due to early nuclear maturation, leading to aging of oocytes, and indicate a need for further research to understand the underlying mechanisms of these effects during vitrification.
Article Synopsis
- In vitro maturation (IVM) of porcine cumulus-oocyte complexes (COCs) is negatively affected by high levels of alpha-macroglobulin (A2M), leading to reduced expansion of COCs.
- Two theories were tested to explain this issue: one involving the decreased availability of epidermal growth factor (EGF) due to binding with A2M, and the other related to the inhibition of zinc-dependent metalloproteases by tissue inhibitor of metalloproteases-3 (TIMP-3).
- The study found that increasing EGF levels did not enhance cumulus expansion, while TIMP-3 showed effects only in the presence of A2M, suggesting a shared target between A2M and TIM
Article Synopsis
- The study assessed the impact of adding polyethylene glycol (PEG) and Supercool X-1000 (SC) to a vitrification solution for immature porcine oocytes.
- Experiment 1 showed that PEG did not enhance oocyte survival or embryo development compared to non-vitrified oocytes; all outcomes were lower with PEG.
- In Experiment 2, SC demonstrated better cleavage rates in surviving oocytes, but overall development into blastocysts was still not improved compared to non-vitrified controls.
Article Synopsis
- The study investigates a technique called cytoplast fusion to enhance the maturation and developmental success of pig oocytes taken from early antral follicles.
- It compares this technique (CFR group) to germinal vesicle transfer (GVTR group) and finds that cytoplast fusion leads to a higher maturation rate and developmental competence.
- Overall, the findings suggest that cytoplast fusion is more effective than GV transfer, achieving better blastocyst development and cell numbers comparable to a control group.
Article Synopsis
- Polyspermy, which is the fertilization of an egg by more than one sperm, is a significant challenge in porcine in vitro fertilization (IVF), leading to low-quality blastocysts compared to those developed in vivo.
- The review highlights the importance of the interaction between oocytes and cumulus cells during in vitro maturation (IVM) in regulating processes like cumulus expansion and oocyte maturation.
- Focusing on maintaining high levels of cAMP and using oocyte-secreted factors (OSFs) during IVM can improve oocyte maturation and developmental potential, especially when combined with epidermal growth factor (EGF) signaling.
Article Synopsis
- Various viruses found in porcine semen pose risks to animal health, public health, and international trade, especially given the reliance on artificial insemination (AI) in pig farming.* -
- The contamination of semen can occur through infected boars or during collection and processing, leading to issues like reduced semen quality and disease in recipient females.* -
- To minimize disease transmission, it's essential to ensure boars are healthy, implement strict biosecurity measures, and conduct regular health monitoring, while continuing research on new semen processing methods.*
Co-culture of cumulus-oocyte complexes (COCs) with denuded oocytes (DOs) during in vitro maturation (IVM) was reported to improve the developmental competence of oocytes via oocyte-secreted factors in cattle. The aim of the present study was to investigate if addition of DOs during IVM can improve in vitro fertilization (IVF) and in vitro culture (IVC) results for oocytes in a defined in vitro production system in pigs. The maturation medium was porcine oocyte medium supplemented with gonadotropins, dbcAMP and β-mercaptoethanol.
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