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Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view
Get PDFIt is now approximately 25 years since the sheep Dolly, the first cloned mammal where the somatic cell nucleus from an adult donor was used for transfer, was born. So far, somatic cell nucleus transfer, where G1-phase nuclei are transferred into cytoplasts obtained by enucleation of mature metaphase II (MII) oocytes followed by the activation of the reconstructed cells, is the most efficient approach to reprogram/remodel the differentiated nucleus. In general, in an enucleated oocyte (cytoplast), the nuclear envelope (NE, membrane) of an injected somatic cell nucleus breaks down and chromosomes condense. This condensation phase is followed, after subsequent activation, by chromatin decondensation and formation of a pseudo-pronucleus (i) whose morphology should resemble the natural postfertilization pronuclei (PNs). Thus, the volume of the transferred nuclei increases considerably by incorporating the content released from the germinal vesicles (GVs). In parallel, the transferred nucleus genes must be reset and function similarly as the relevant genes in normal embryo reprogramming. This, among others, covers the relevant epigenetic modifications and the appropriate organization of chromatin in pseudo-pronuclei. While reprogramming in SCNT is often discussed, the remodeling of transferred nuclei is much less studied, particularly in the context of the developmental potential of SCNT embryos. It is now evident that correct reprogramming mirrors appropriate remodeling. At the same time, it is widely accepted that the process of rebuilding the nucleus following SCNT is instrumental to the overall success of this procedure. Thus, in our contribution, we will mostly focus on the remodeling of transferred nuclei. In particular, we discuss the oocyte organelles that are essential for the development of SCNT embryos
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of on in vitro maturation of porcine oocytes
Get PDFLysmeral (Lilial, Butylphenyl Methylpropional) is a synthetically produced aldehyde. It is used for its typical lily of the valley-like scent as a perfume ingredient in cosmetic products. It is typically found, for example, in cleaning products. It is on the list of the 26 most well-known synthetic allergens and has been shown to be present in human urine and subsequently in wastewater. According to some opinions, lysmeral should be classified as an endocrine disruptor, which are substances that can interfere with the body's endocrine system. As these substances often affect mammalian reproduction, it is in society's interest to address them, given that they are commonly found in the environment. Lysmeral was not properly tested before being placed on the market and all its effects on organisms are still unknown. The hypothesis of this thesis is that exposure to lysmeral causes undesirable changes in the meiotic maturation of porcine oocytes in vitro and the aim is to investigate the effect of lysmeral, at concentrations corresponding to normal human exposures, on specific markers of meiotic maturation of porcine oocytes. The results confirm the negative effect of lysmeral on the smooth progression of meiotic maturation and the achievement of the final stage of porcine oocyte maturation in vitro...
Effect of pergafast 201 on selected markers of in vitro maturation of porcine oocytes.
Get PDFPergafast 201 (N-(p-Toluenesulfonyl)-N'-(3-p-toluenesulfonyloxyphenyl)urea) je patentovaná vývojka barvy, která se nabízí jako alternativa k hojně využívaným bisfenolům A a S (BPA, BPS). U těchto látek byl prokázán negativní vliv na lidské zdraví a reprodukci již ve velmi nízkých dávkách a jedná se o endokrinní disruptory zasahující mimo jiné do procesu meiotického zrání. Účinky pergafastu 201 na savčí organismus v rámci oogeneze zatím nebyly sledovány. Cílem této práce bylo zhodnocení vlivu pergafastu 201 na vybrané specifické markery meiotického zrání po expozici prasečích oocytů pergafastem 201 v nízkých koncentracích in vitro. Tato práce je první, která popisujenegativní účinky pergafastu 201 na zrání prasečích oocytů in vitro, potvrzuje negativní vliv pergafastu na průběh meiotického zrání a na schopnost oocytu dosáhnout konečného stádia zrání a také jeho vliv na zvýšenou incidenci abnormálních dělících vřetének. Data ukazují vliv PF201 na metylaci epigenetických markerů H3K4me2 a H3K9me3. Předběžné výsledky také naznačují jeho vliv na expresi mRNA estrogenových receptorů α a β. Souhrnně tyto výsledky ukazují na případná rizika spojená s používáním této látky jako alternativy bisfenolů a nutnost prozkoumání jeho vlivu nejen na reprodukční zdraví lidí a zvířat.Pergafast 201 (N-(p-Toluenesulfonyl)-N'-(3-p-toluenesulfonyloxyphenyl)urea) is a patented color developer that is offered as an alternative to the widely used bisphenols A and S (BPA, BPS). These substances have been shown to have a negative effect on human health and reproduction even in very low doses, and they are endocrine disruptors affecting, among other things, the process of meiotic maturation. The effects of pergafast 201 on the mammalian organism during oogenesis have not yet been monitored. The aim of this work was to evaluate the effect of pergafast 201 on selected specific markers of meiotic maturation after exposure of porcine oocytes to pergafast 201 in low concentrations in vitro. This work is the first to describe the negative effects of pergafast 201 on the maturation of porcine oocytes in vitro, confirming the negative effect of pergafast on the course of meiotic maturation and on the ability of the oocyte to reach the final stage of maturation, as well as its effect on the increased incidence of abnormal dividing spindles. The data show the effect of PF201 on the methylation of epigenetic markers H3K4me2 and H3K9me3. Preliminary results also indicate its effect on the mRNA expression of estrogen receptors α and β. Collectively, these results indicate the possible risks...Katedra buněčné biologieDepartment of Cell BiologyPřírodovědecká fakultaFaculty of Scienc
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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