Littérature scientifique sur le sujet « Reproductive cell »
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Articles de revues sur le sujet "Reproductive cell"
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Vidane, Atanásio S., Helena D. Zomer, Bruna M. M. Oliveira, Carina F. Guimarães, Cláudia B. Fernandes, Felipe Perecin, Luciano A. Silva, Maria A. Miglino, Flávio V. Meirelles et Carlos E. Ambrósio. « Reproductive Stem Cell Differentiation ». Reproductive Sciences 20, no 10 (18 février 2013) : 1137–43. http://dx.doi.org/10.1177/1933719113477484.
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Zadrag-Tecza, Renata, Magdalena Kwolek-Mirek, Małgorzata Alabrudzińska et Adrianna Skoneczna. « Cell Size Influences the Reproductive Potential and Total Lifespan of theSaccharomyces cerevisiaeYeast as Revealed by the Analysis of Polyploid Strains ». Oxidative Medicine and Cellular Longevity 2018 (2018) : 1–17. http://dx.doi.org/10.1155/2018/1898421.
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The total lifespan of the yeastSaccharomyces cerevisiaemay be divided into two phases: the reproductive phase, during which the cell undergoes mitosis cycles to produce successive buds, and the postreproductive phase, which extends from the last division to cell death. These phases may be regulated by a common mechanism or by distinct ones. In this paper, we proposed a more comprehensive approach to reveal the mechanisms that regulate both reproductive potential and total lifespan in cell size context. Our study was based on yeast cells, whose size was determined by increased genome copy number, ranging from haploid to tetraploid. Such experiments enabled us to test the hypertrophy hypothesis, which postulates that excessive size achieved by the cell—the hypertrophy state—is the reason preventing the cell from further proliferation. This hypothesis defines the reproductive potential value as the difference between the maximal size that a cell can reach and the threshold value, which allows a cell to undergo its first cell cycle and the rate of the cell size to increase per generation. Here, we showed that cell size has an important impact on not only the reproductive potential but also the total lifespan of this cell. Moreover, the maximal cell size value, which limits its reproduction capacity, can be regulated by different factors and differs depending on the strain ploidy. The achievement of excessive size by the cell (hypertrophic state) may lead to two distinct phenomena: the cessation of reproduction without “mother” cell death and the cessation of reproduction with cell death by bursting, which has not been shown before.
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Kustan, Jacqueline M., Karen P. Maruska et Russell D. Fernald. « Subordinate male cichlids retain reproductive competence during social suppression ». Proceedings of the Royal Society B : Biological Sciences 279, no 1728 (6 juillet 2011) : 434–43. http://dx.doi.org/10.1098/rspb.2011.0997.
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Subordinate males, which are excluded from reproduction often save energy by reducing their investment in sperm production. However, if their position in a dominance hierarchy changes suddenly they should also rapidly attain fertilization capability. Here, we asked how social suppression and ascension to dominance influences sperm quality, spermatogenesis and reproductive competence in the cichlid Astatotilapia burtoni , where reproduction is tightly coupled to social status. Dominant territorial (T) males are reproductively active while subordinate non-territorial (NT) males are suppressed, but given the opportunity, NT males will perform dominance behaviours within minutes and attain T male testes size within days. Using the thymidine analogue 5-bromo-2-deoxyuridine (BrdU) to label germ cell proliferation, we found that the spermatogenic cycle takes approximately 11–12 days, and social status had no effect on proliferation, suggesting that spermatogenesis continues during reproductive suppression. Although sperm velocity did not differ among social states, NT males had reduced sperm motility. Remarkably, males ascending in status showed sperm motility equivalent to T males within 24 h. Males also successfully reproduced within hours of social opportunity, despite four to five weeks of suppression and reduced testis size. Our data suggest that NT males maintain reproductive potential during suppression possibly as a strategy to rapidly improve reproductive fitness upon social opportunity.
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Lie, Merete. « Reproductive Images : The Autonomous Cell ». Science as Culture 21, no 4 (décembre 2012) : 475–96. http://dx.doi.org/10.1080/09505431.2012.679728.
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Boddy, Amy M., Hanna Kokko, Felix Breden, Gerald S. Wilkinson et C. Athena Aktipis. « Cancer susceptibility and reproductive trade-offs : a model of the evolution of cancer defences ». Philosophical Transactions of the Royal Society B : Biological Sciences 370, no 1673 (19 juillet 2015) : 20140220. http://dx.doi.org/10.1098/rstb.2014.0220.
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The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction.
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Templeman, Nicole M., et Coleen T. Murphy. « Regulation of reproduction and longevity by nutrient-sensing pathways ». Journal of Cell Biology 217, no 1 (26 octobre 2017) : 93–106. http://dx.doi.org/10.1083/jcb.201707168.
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Nutrients are necessary for life, as they are a crucial requirement for biological processes including reproduction, somatic growth, and tissue maintenance. Therefore, signaling systems involved in detecting and interpreting nutrient or energy levels—most notably, the insulin/insulin-like growth factor 1 (IGF-1) signaling pathway, mechanistic target of rapamycin (mTOR), and adenosine monophosphate-activated protein kinase (AMPK)—play important roles in regulating physiological decisions to reproduce, grow, and age. In this review, we discuss the connections between reproductive senescence and somatic aging and give an overview of the involvement of nutrient-sensing pathways in controlling both reproductive function and lifespan. Although the molecular mechanisms that affect these processes can be influenced by distinct tissue-, temporal-, and pathway-specific signaling events, the progression of reproductive aging and somatic aging is systemically coordinated by integrated nutrient-sensing signaling pathways regulating somatic tissue maintenance in conjunction with reproductive capacity.
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Liu, Hong-Bo, Pei-Ru Lv, Ruo-Gang He, Xiao-Gan Yang, Xiao-E. Qin, Tian-Biao Pan, Guang-Yun Huang et al. « Cloned Guangxi Bama Minipig (Sus scrofa) and Its Offspring Have Normal Reproductive Performance ». Cellular Reprogramming 12, no 5 (octobre 2010) : 543–50. http://dx.doi.org/10.1089/cell.2009.0094.
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Renfree, Marilyn B. « WOMEN IN REPRODUCTIVE SCIENCE : Reproduction down under ». Reproduction 158, no 6 (décembre 2019) : F127—F137. http://dx.doi.org/10.1530/rep-19-0230.
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Australia is home to a unique assembly of mammals – the marsupials and monotremes. Despite this uniqueness, they have been largely ignored by the biomedical scientific community, and yet study of marsupials has contributed to modern research on reproduction, development, evolution, conservation, molecular and comparative genomics. My lifetime passion for these long-neglected Australian fauna has led to unexpected discoveries and insights that challenged assumptions and opened up new areas of international research. I used a range of disciplinary expertise to pursue the study of these unique mammals. My main experimental species has been the tammar wallaby that I have used as a model species to investigate and understand not only biomedical problems but also to provide knowledge that is critical for the continued conservation and management of Australia’s dwindling native mammals. This model provided more than a few surprises for me and my wonderful team of students, post-docs and collaborators about how hormones, genes and signalling molecules control reproductive biology and development in a wider context as well as how the interactions of the environment with mother and conceptus, with mother and fetus and mother and young ultimately control most aspects of successful reproduction in mammals.
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Wocławek-Potocka, Izabela, Paulina Rawińska, Ilona Kowalczyk-Zieba, Dorota Boruszewska, Emilia Sinderewicz, Tomasz Waśniewski et Dariusz Jan Skarzynski. « Lysophosphatidic Acid (LPA) Signaling in Human and Ruminant Reproductive Tract ». Mediators of Inflammation 2014 (2014) : 1–14. http://dx.doi.org/10.1155/2014/649702.
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Lysophosphatidic acid (LPA) through activating its G protein-coupled receptors (LPAR 1–6) exerts diverse cellular effects that in turn influence several physiological processes including reproductive function of the female. Studies in various species of animals and also in humans have identified important roles for the receptor-mediated LPA signaling in multiple aspects of human and animal reproductive tract function. These aspects range from ovarian and uterine function, estrous cycle regulation, early embryo development, embryo implantation, decidualization to pregnancy maintenance and parturition. LPA signaling can also have pathological consequences, influencing aspects of endometriosis and reproductive tissue associated tumors. The review describes recent progress in LPA signaling research relevant to human and ruminant reproduction, pointing at the cow as a relevant model to study LPA influence on the human reproductive performance.
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Li, Lin, Risako Yang, Chenghong Yin et Kehkooi Kee. « Studying human reproductive biology through single-cell analysis and in vitro differentiation of stem cells into germ cell-like cells ». Human Reproduction Update 26, no 5 (28 mai 2020) : 670–88. http://dx.doi.org/10.1093/humupd/dmaa021.
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Abstract BACKGROUND Understanding the molecular and cellular mechanisms of human reproductive development has been limited by the scarcity of human samples and ethical constraints. Recently, in vitro differentiation of human pluripotent stem cells into germ cells and single-cell analyses have opened new avenues to directly study human germ cells and identify unique mechanisms in human reproductive development. OBJECTIVE AND RATIONALE The goal of this review is to collate novel findings and insightful discoveries with these new methodologies, aiming at introducing researchers and clinicians to the use of these tools to study human reproductive biology and develop treatments for infertility. SEARCH METHODS PubMed was used to search articles and reviews with the following main keywords: in vitro differentiation, human stem cells, single-cell analysis, spermatogenesis, oogenesis, germ cells and other key terms related to these subjects. The search period included all publications from 2000 until now. OUTCOMES Single-cell analyses of human gonads have identified many important gene markers at different developmental stages and in subpopulations of cells. To validate the functional roles of these gene markers, researchers have used the in vitro differentiation of human pluripotent cells into germ cells and confirmed that some genetic requirements are unique in human germ cells and are not conserved in mouse models. Moreover, transcriptional regulatory networks and the interaction of germ and somatic cells in gonads were elucidated in these studies. WIDER IMPLICATIONS Single-cell analyses allow researchers to identify gene markers and potential regulatory networks using limited clinical samples. On the other hand, in vitro differentiation methods provide clinical researchers with tools to examine these newly identify gene markers and study the causative effects of mutations previously associated with infertility. Combining these two methodologies, researchers can identify gene markers and networks which are essential and unique in human reproductive development, thereby producing more accurate diagnostic tools for assessing reproductive disorders and developing treatments for infertility.
Thèses sur le sujet "Reproductive cell"
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Hofsten, Jonas von. « Developmental and reproductive regulation of NR5A genes in teleosts ». Doctoral thesis, Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-374.
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Giedt, Michelle Suzanne. « JAK/STAT SIGNALING REGULATES GAMETOGENESIS AND AGE-RELATED REPRODUCTIVE MAINTENANCE ». UKnowledge, 2018. https://uknowledge.uky.edu/biology_etds/52.
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Cell signaling is central to integration of internal and external cues that regulate development and homeostasis. Most development is thought of as pre-adult, but limited developmental processes occur in adults. Gametogenesis incorporates elements of both these facets, with a distinct developmental plan for gamete synthesis which is regulated by integration of homeostatic inputs such as nutrient status, and environmental cues. Signaling pathways integrate and transduce information from these cues to evoke a response. A decline in homeostasis and subsequent cues occurs over time, in the case of reproductive tissues leading to a progressive loss of fertility. The Janus Kinase and Signal Transducer and Activator of Transcription or Jak/Stat signaling pathway is conserved between vertebrates and invertebrates and is necessary for numerous functions needed to maintain organism and reproductive homeostasis, as well as contributing to various developmental events. The pathway in the fruit fly Drosophila melanogaster, is composed of a single receptor, Domeless, one Janus kinase, Hopscotch, one known effector, Stat92E, and the Unpaired family of ligands consisting of Upd, Upd2, and Upd3. Jak/Stat signaling is highly pleiotropic in both sexes with involvement in homeostasis and reproduction, making it an ideal model for studying the role of signaling in reproductive aging. Reduction of pathway activity in females results in a higher proportion of unfertilized eggs, which increases with age, and in males leads to a premature onset of infertility. Central to both is integration through cell signaling to evoke an appropriate response. This dissertation explores two of the requirements for Jak/Stat signaling: the pleiotropic requirement for Jak/Stat activity during oogenesis and male reproductive maintenance.
Jak/Stat functions from the beginning of oogenesis, in the stem cell niche. From there it participates in multiple functions including specification of a subset of somatic cells called the border cells through the polar cells, a pair of cells at either pole of the egg. Pathway stimulation in the border cells drives their migration with the polar cells to the oocyte boundary, where the polar cells each form an extension in a coordinated manner into the micropyle, the means for sperm entrance during fertilization. Loss of Jak/Stat activity in the border cells prevents border cell migration. While border cell migration has been well studied, polar cell involvement after completion of border cell migration is less well known. To investigate the requirements for polar cell activity and Jak/Stat activity after the completion of border cell migration, we reduced Jak/Stat signaling in the polar cells which, while having no effect on border cell migration, results in blocked micropyles due to loss of coordination of extensions during their outgrowth. Reduced function in the polar cells did not significantly affect expression of adhesion molecules. But, the loss of Stat92E is phenocopied by loss of DE-cadherin. Hence, these results indicate a previously unknown autocrine requirement for Jak/Stat activity in the polar cells.
The testes also have a continuous requirement for Jak/Stat activity for stem cell maintenance and differentiation of the germline into mature sperm. Reproductive maintenance not only requires sustained production of gametes, but reproductive tissues are also subject to deterioration of homeostatic functions that contribute to organismal aging. Males from thirty-nine lines of the Drosophila Genetic Reference Panel (DGRP), a panel of inbred, fully sequenced lines, were screened for age at infertility. Data were used to perform a genome-wide association study (GWAS) to identify the genetic architecture of reproductive aging. Candidate variants associated with cell signaling regulators, genes with functions in maintaining cell homeostasis, and organism behavior were uncovered. Notably, several SNPs fell in and near Ptp61F, a negative regulator of Jak/Stat activity. While variants in the primary components of the Jak/Stat pathway were not identified, the general classes of candidate loci functions reflect the requirements for homeostasis, metabolism, and development that have been shown by other studies examining the genetics of aging and fecundity. Thus, we show that Jak/Stat has an amazing amount of pleiotropy that encompasses both the real-time functions of fertility and the time related process of aging.
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Van, Praet Oliver. « Co-expression and interaction of cubilin and megalin in the adult male rat reproductive system ». Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29485.
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Cubilin is a peripheral membrane protein that co-operates with the endocytic receptor megalin to mediate the endocytosis of ligands in various polarized epithelia. Megalin is expressed in the male reproductive tract where is has been implicated in the process of sperm membrane remodeling. A potential role for cubilin in the male reproductive tract has not been explored. Using RT-PCR, we found that cubilin and megalin mRNAs are expressed in the efferent ducts, corpus and cauda epididymides, and proximal and distal vas deferens. Immunohistological analysis revealed that cubilin was expressed in non-ciliated cells of the efferent ducts, principal cells of the corpus and cauda epididymides and vas deferens. Electron microscopic immunogold labeling showed cubilin in endocytic pits, endocytic vesicles and endosomes of these cells. The expression profile of cubilin in the male reproductive tract was coincident with that of megalin except in principal cells of the caput epididymidis. Double immunogold labeling showed that cubilin and megalin co-localized with one another within the endocytic apparatus and recycling vesicles of efferent duct cells. Neither protein was found in lysosomes. Injection of RAP, an antagonist of megalin interaction with cubilin, reduced the level of intracellular cubilin in cells of the efferent ducts and vas deferens. In conclusion, cubilin and megalin are co-expressed in cells of the epididymis and vas deferens and the endocytosis of cubilin in these tissues is dependent on megalin. Together, these findings highlight the potential for a joint endocytic role for cubilin and megalin in the male reproductive tract.
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Mercurio, S. « ROLE OF STEROID HORMONES IN ECHINOID REPRODUCTIVE BIOLOGY ». Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/230752.
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Echinoid reproductive cycle has been extensively studied in several species but the mechanisms regulating gametogenesis processes are still scarcely understood. Apart from environmental factors, different research have suggested a steroid role in gonad maturation and growth. Particularly, in echinoderms steroid involvement in reproduction has been suggested by both studies on seasonal changes of steroid levels during the gonadal cycle and experiments of hormone administration. Nevertheless, the steroid function in echinoid reproductive processes has not been clearly identified, probably due to the low number of studies and the big variability of results reported. Thus, the main aim of this research project was to shed light on echinoid endocrinology and, in particular, to clarify the involvement of sex-steroid hormones in sea urchin reproductive biology. This was achieved employing both in vivo and in vitro approaches.
First of all, considering the lack of studies on the development of effective cell cultures from echinoderm gonads, primary cell cultures from ovaries of the edible sea urchin Paracentrotus lividus were developed. Ovary cell phenotypes, present in culture, were identified and characterized by different microscopic techniques. Although cell cultures could be produced from ovaries at all stages of maturation, the cells appeared healthier and viable, displaying a higher survival rate, when ovaries at early stages of gametogenesis were used. In terms of culture medium, ovarian cells were successfully cultured in modified Leibovitz-15 medium, whereas poor results were obtained in Minimum Essential Medium Eagle and Medium 199. Different substrates were tested but ovarian cells completely adhered only on poly-L-lysine. To improve in vitro conditions and stimulate cell proliferation different serum-supplements were tested. Fetal Calf Serum and an originally developed Pluteus Extract resulted to be detrimental to cell survival, apparently accelerating processes of cell death. In contrast, cells cultured with sea urchin Egg Extract appeared larger and healthier, displaying an increased longevity that allowed to maintain them for up to 1 month. Overall this study provides new experimental bases and procedures for producing successfully long-term primary cell cultures from sea urchin ovaries, providing a simple and versatile experimental tool for research in echinoderm reproductive biology.
Subsequently, in vivo and in vitro experiments, specifically addressed to determine possible 17β-estradiol (E2) and testosterone (T) involvement in echinoid reproduction, were performed. An in vivo long-term experiment of steroid dietary administration was performed in adult specimens of P. lividus. The experimental plan was specifically designed in order to reduce individual variability and synchronize the experimental animals at the same starting maturative condition. We analysed and compared different reproductive parameters (Gonad Index, Maturative Index and maturative stages distribution) in 4 experimental groups: control group (CTL), E2 and T groups fed with pellets containing respectively 17β-estradiol and testosterone, and E2-4 weeks group fed with control pellets for the first 4 weeks and then treated with 17β-estradiol. This latter was chosen in order to verify the existence of a specific E2-sensitive gametogenic stage, as proposed in different asteroid species.
Possible steroid effects on P. lividus female reproduction was also investigated with an in vitro approach. Cells, isolated by ovaries in the same maturative conditions considered in the in vivo experiments, were cultured in presence of E2 and T physiological concentrations for 2 weeks. Effects on ovarian cell morphology and behaviour were investigated. In addition, steroid regulation of the Major Yolk Protein (MYP) expression was analyzed 24 and 48 hours after E2 and T exposure. According to our results, E2 and T do not markedly influence echinoid gonad maturation and, particularly, they do not promote gamete maturation. Hormonal dietary administration did not induce striking variations in the considered reproductive parameters and no effect was observed also when males and females were analyzed separately. In addition, no specific maturative stage sensitive to E2 was found, suggesting the existence of different hormonal mechanisms in asteroids and echinoids. Similar considerations could be reported taking into account the in vitro experiments. E2 and T exposure did not affect ovarian cell size and behaviour nor MYP expression.
The obtained results suggest that these hormones are not directly involved in either gamete maturation, as demonstrated for vertebrates, or in vitellogenesis processes, as reported for several asteroid species. However a possible involvement of steroids in echinoid physiology cannot be completely excluded and their role in the regulation of lipid metabolism and protein synthesis during the different reproductive stages should be strongly considered as suggested by several authors.
Further specific research on steroid hormone mode of action, physiological function and metabolism are therefore needed to completely understand echinoid reproduction and endocrinology.
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Chen, Hsin-Ying. « T CELL RESPONSE TO INFECTION BY THE PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS ». NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-01062005-170050/.
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The purpose of the research has been to characterize the response of naïve or virus-specific swine T lymphocytes from different lymphoid compartments to Porcine Reproductive and Respiratory Syndrome Virus (PRRSV). Peripheral blood mononuclear cells (PBMCs), tracheobronchial lymph node (TLN) and lateral retropharyngeal lymph node (LLN) cells were labeled with PKH67 green fluorescence dye to measure cell proliferation and surface phenotypes were examined using anti-CD4, anti-CD8 or anti-CD25 monoclonal antibodies. Stimulation with Concanavalin A was also included as a positive control. Our results show that potential virus-specific T lymphocytes were found in the peripheral blood, although no cell proliferation was found in cultures of lymph node cells. We did find that the percentages of CD8+ T cells in cultures of lymph node cells from the virus-infected pig increased after in vitro stimulation with the Powell virus compared to the lymph node cells cultured in media only, suggesting that CD8+ T lymphocytes may play a role in the virus clearance and immune memory to PRRSV.
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Dias, Tânia Isabel Rodrigues Amaral. « Evaluation of cell death markers and reproductive parameters in models of diabetes mellitus ». Master's thesis, Universidade da Beira Interior, 2012. http://hdl.handle.net/10400.6/1121.
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Diabetes mellitus (DM) represents one of the greatest threats to modern global health and its incidence is rapidly rising worldwide. It describes a metabolic disorder characterized by hyperglycaemia resulting from defective insulin secretion, resistance to insulin action, or both. There are two types of DM, type-1 DM (T1DM) and type-2 DM (T2DM), both associated with male infertility. T1DM is associated with insulin deprivation and although the overall in vivo effects in the reproductive function is well known, there is a lack of studies concerning about the insulin control over the physiological functions of cells from the reproductive system. Importantly, the in vivo studies are often focused after the disease is fully establish, but it is known that a prediabetic state, which is characterized by insulin resistance, precedes the development of DM, especially T2DM. With our work, we aimed to further investigate the association between DM and male infertility by analyzing several apoptotic markers and reproductive parameters. To do so, we simulated type 1 DM in cultured rat Sertoli cells and analyzed the mRNA and protein expression levels of several cellular markers involved in the mitochondrial apoptotic pathway. We also developed an animal model of prediabetes to evaluate the effect of this pathological state in the reproductive parameters as well as in the mitochondrial apoptotic pathway.
Our results lead us to suggest that insulin interferes with the interaction between pro and anti-apoptotic proteins. As the interaction of these proteins decide the cell fate and exert a strict control over the apoptotic signaling, insulin has a key role in the maintenance of the spermatogenesis. Our rat model shared many of the clinical and metabolic characteristics of the prediabetic state observed in humans such as glucose resistance and progression from normoglycaemia/normoinsulinemia to moderate hyperglycaemia/hyperinsulinemia due to food intake. This prediabetic state induced important alterations in cauda epididymis spermatozoa morphology showing that these animals may develop subfertility or fertility problems. The apoptotic signalling in cauda epididymis spermatozoa of the high-energy (HED) fed animals presented lower Bax mRNA levels and lower cytC protein levels although the apoptotic endpoint, caspase-3 activity, was not altered. This suggests that the apoptotic process may be controlled by other mechanisms rather than the mitochondrial pro-apoptotic proteins, such as the anti-apoptotic cellular systems.
Those two experimental models led us to conclude that the subfertility/infertility problems caused by DM may be mediated by insulin, which has an important effect in the regulation of the interaction between pro and anti-apoptotic proteins and special attention must be taken in the prediabetic state where crucial alterations in rat spermatozoa occurred. Due to the rising incidence and associated complications of DM and male infertility it is crucial to further investigate in these two systems to isolate possible mechanisms and evaluate the overall effects as a strategy to develop possible therapeutics.A diabetes mellitus (DM) representa uma das maiores ameaças à saúde global moderna e a sua incidência está a aumentar rapidamente em todo o mundo. Esta doença consiste numa desordem metabólica, caracterizada por hiperglicemia, resultante de uma secreção defeituosa de insulina, resistência à ação da insulina ou ambas. Existem dois tipos de DM, tipo 1 e tipo 2, ambas as condições relacionadas com a infertilidade masculina. A DM tipo 1 está associada com a privação de insulina e embora os efeitos globais in vivo na função reprodutiva sejam bem conhecidos, há uma falta de estudos relativamente ao controlo da insulina sobre as funções fisiológicas das células do sistema reprodutivo. Sobretudo, os estudos in vivo são frequentemente feitos depois de a doença estar completamente estabelecida, mas sabe-se que há um estado pré-diabético, caracterizado por resistência à insulina, que antecede o desenvolvimento da DM, especialmente da DM tipo 2. Com o nosso trabalho, pretendemos investigar mais profundamente a ligação entre a DM e a infertilidade masculina, através da análise de vários marcadores de morte celular e de parâmetros reprodutivos. Para isso, simulámos o estado de DM tipo 1 humano em células de Sertoli de rato e analisámos os níveis de expressão de mRNA e proteína de vários marcadores de morte celular envolvidos na via mitocondrial. Por outro lado, também desenvolvemos um modelo animal de pré-diabetes de modo a reproduzir esta condição patológica e avaliar alterações produzidas nos parâmetros reprodutivos, assim como nos níveis de expressão de mRNA e proteína de marcadores de morte celular envolvidos na via mitocondrial. Os resultados obtidos levam-nos a sugerir que a insulina interfere com a interação entre proteínas pró- e anti-apoptóticas. Uma vez que esta interação pode decidir o destino celular e exercer um controlo rigoroso sobre a sinalização apoptótica, a insulina terá um papel chave na manutenção da espermatogénese. O modelo de rato utilizado compartilhava muitas das características clínicas e metabólicas do estado pré-diabético observado em humanos, tais como resistência à glucose e a progressão de normoglicemia/normoinsulinemia para hiperglicemia/hiperinsulinemia moderada devido à ingestão de alimentos. Este estado prédiabético induziu alterações significativas na morfologia dos espermatozoides da cauda do epidídimo, mostrando que esses animais poderão desenvolver problemas de subfertilidade ou de fertilidade. Na sinalização apoptótica na cauda do epidídimo, os animais sujeitos à dieta de alta energia (HED) apresentaram níveis mais baixos de mRNA Bax e da proteína citocromo C, embora a avaliação quantitativa do endpoint apoptótico, a atividade da caspase-3, não tenha evidenciado quaisquer alterações entre a situação HED e controle. Isto sugere que o processo apoptótico pode ser controlado por outros mecanismos que não somente os proteicos pró-apoptóticos mitocondriais, como por exemplo os sistemas anti-apoptóticos celulares. Os resultados obtidos com estes dois modelos experimentais levam-nos a concluir que os problemas de subfertilidade/infertilidade causados pela DM podem ser mediados pela insulina, que tem um efeito importante na regulação da interação entre proteínas pró e antiapoptóticas e, por esse motivo, deverá ser dedicada uma atenção especial às disfunções ocorridas no estado pré-diabético, onde observámos alterações cruciais na morfologia de espermatozoides epididimais de ratos. Devido à crescente incidência da DM e às complicações associadas ao nível da infertilidade masculina é fundamental aprofundar o conhecimento nestes dois sistemas, de modo a isolar possíveis mecanismos envolvidos e a avaliar os efeitos globais, como uma estratégia para desenvolver possíveis abordagens terapêuticas.
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Ismail, Rubina Siddiqi. « Expression, hormonal regulation and function of Kit ligand, the ligand for thec-Kit receptor, in the rat reproductive system ». Thesis, University of Ottawa (Canada), 1998. http://hdl.handle.net/10393/4364.
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Mice having mutations at the Kit and Mast Cell Growth Factor loci suffer from severe development abnormalities in gametogenesis suggesting that the protein products produced at these loci, Kit receptor and kit ligand (KL), serve an essential role in the reproductive system. The purposes of this study were: (1) to identify the expression Kit and KL in the ovary which is the organ in which gametogenesis occurs in the female animal, (2) to determine the expression of Kit and KL in the female reproductive tract, (3) to determine the influence of hormones and growth factors on the expression of Kit and KL, and (4) to identify the functional significance of KL/Kit interactions in the reproductive system. Kit receptor expression was identified in the oocytes of antral follicles and KL expression was seen in granulosa cells in growing and antral follicles. In antral follicles, KL expression was greatest in cumulus granulosa cells and only those mural granulosa cells closest to the oocyte and antral cavity. Low KL expression was seen in the mural granulosa cells closest to the basement membrane. This pattern of KL expression in antral follicles suggested a role for KL in oocyte function. There was an inhibition of oocyte meiotic maturation when oocytes from antral follicles were cultured in the presence of KL compared to untreated oocytes. Luteinizing hormone (LH) is the key stimulator of oocyte maturation within the follicle. In vivo stimulation with LH resulted in a loss of KL expression in cumulus granulosa cells and a shift in the production of membrane-bound KL to more soluble KL in mural granulosa cells. Thus, LH-stimulated oocyte maturation may be partly mediated by the removal of KL in the cumulus granulosa cells and the production of a potentially less active form of KL by mural granulosa cells. The expression of KL in granulosa cells was upregulated at the transcript level by treatment with FSH, LH, or both in vivo and in vitro, as well as with membrane-permeable analogues of cyclic adenosine monophosphate (cAMP), whereas KL mRNA expression decreased with steroid hormone stimulation. KL but not Kit mRNA expression was seen in the ovarian surface epithelium. KL expression in ovarian surface epithelium derived-cells was influenced by both dibutyryl cAMP and transforming growth factor-$\beta$ stimulation. These studies would indicate that the ovarian surface epithelium is a site of KL production and that this expression can be regulated by ovarian factors. Preimplantation embryos have been previously shown to express Kit receptors. In this study KL expression was demonstrated in oviducts and uteri and gonadotropin-stimulated increases in oviductal KL mRNA expression were seen. Furthermore, preimplantation embryo survival and development were enhanced with KL suggesting that KL has stimulatory effects on the mitotic cell cycle of the embryo. (Abstract shortened by UMI.)
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Uebler, Susanne [Verfasser], Thomas [Akademischer Betreuer] Dresselhaus et Reinhard [Akademischer Betreuer] Sterner. « Analysis of cell-cell communication during reproductive processes by EA1-like peptides in maize / Susanne Uebler ; Thomas Dresselhaus, Reinhard Sterner ». Regensburg : Universitätsbibliothek Regensburg, 2015. http://d-nb.info/1122354932/34.
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Uebler, Susanne Verfasser], Thomas [Akademischer Betreuer] [Dresselhaus et Reinhard [Akademischer Betreuer] Sterner. « Analysis of cell-cell communication during reproductive processes by EA1-like peptides in maize / Susanne Uebler ; Thomas Dresselhaus, Reinhard Sterner ». Regensburg : Universitätsbibliothek Regensburg, 2015. http://d-nb.info/1122354932/34.
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Perrini, C. « EQUINE AND BOVINE MICROVESICLES DERIVED FROM AMNIOTIC PROGENITOR CELLS IN REGENERATIVE AND REPRODUCTIVE TOPICS ». Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/490022.
Texte intégralRésumé :
Durante questo progetto di dottorato sono stati condotti studi per comprendere la capacità delle cellule mesenchimali amniotiche (AMCs) di agire attraverso meccanismi paracrini. La prima fase del disegno sperimentale ha valutato l’efficacia delle AMCs sulla proliferazione delle cellule endometriali (EDCs) in assenza di un contatto cellula-cellula. Le EDCs sono state co-coltivate in un sistema trans-well con le AMCs o sono state coltivate in presenza del loro medium condizionato (CM). In entrambe le condizioni sperimentali è stato osservato un aumento del tasso di proliferazione delle EDCs definendo, così, il ruolo cruciale dei fattori secreti dalle AMCs come mediatori dell'azione delle cellule staminali. Il CM è composto da fattori solubili e non-solubili rappresentati da microvescicole (MVs). Per capire il ruolo delle MVs e del loro contenuto nell’azione paracrina, la seconda fase del disegno sperimentale è stata incentrata sull’individuazione del tipo di MVs secrete dalle AMCs e sulla loro efficacia in processi infiammatori in vitro su due importanti modelli sperimentali nella specie equina quali l’endometrio ed il tendine. La produzione di MVs è stata ottimizzata attraverso un’ultracentrifugazione del CM a 100.000 g per 1 ora. Attraverso lo strumento Nanosight è stato calcolato che la produzione di MVs da AMCs equine è di circa 2550±71 particelle/cellula, con una dimensione media di 258±55 nm. La microscopia elettronica a trasmissione ha confermato la presenza di vescicole cellulari che per dimensioni e modalità di secrezione sono state classificate come shedding vesicles. Per capire se le cellule endometriali (EDCs) e tendinee (TNCs) fossero target delle MVs secrete dalle AMCs, è stata studiata l’incorporazione delle medesime dopo marcatura con un fluorocromo lipofilico quale il PKH-26. Dopo uno studio di una curva dose-risposta è stato osservato che la dose ottimale per l'incorporazione di MVs in EDCs è stata di 40x106 MVs/ml a 72 h e per le TNCs di 40x106 MVs/ml a 24-48h. Per esaminare l'abilità delle MVs nel contrastare un processo infiammatorio, entrambe le linee cellulari sono state stressate in vitro con LPS e trattate con MVs. La vitalità cellulare, l'espressione di alcuni geni pro-infiammatori ed il rilascio delle rispettive citochine sono stati i parametri impiegati per valutare l’efficacia delle MVs. Per entrambe le linee cellulari, il tasso di apoptosi è drammaticamente salito nelle cellule trattate con LPS, rispetto al controllo (CTR). LPS ha indotto un aumento significativo dell'espressione di TNF-α, IL-6 e IL-1β in EDCs e di MMP-1, MMP-9, MMP-13 e TNF-α in TNCs. Le MVs sono state in grado di contrastare l'effetto di LPS, diminuendo il tasso di apoptosi in entrambe le linee cellulari e riducendo il livello di espressione dei geni pro-infiammatori. Una conferma di questi dati è stata ottenuta attraverso l'analisi delle citochine pro-infiammatorie (TNF-β and IL-6) ed anti-infiammatorie (TGF-α) rilasciate dalle EDCs nel terreno di coltura, confermando l'abilità delle MVs di trasportare molecole capaci di contrastare la risposta infiammatoria in cellule stressate con LPS.
Data l'importanza del contenuto in miRNA delle MVs, sia nelle AMCs sia nelle loro MVs è stata studiata la presenza di tre miRNA (miR-335, miR-146a, and miR-26a-2) coinvolti nella regolazione dei processi infiammatori. Questi tre miRNA sono stati identificati sia nelle AMCs sia nelle MVs, di conseguenza, è possibile ipotizzare che l'espressione genica dopo infiammazione con LPS e trattamento con MVs possa essere stato modulato dal trasferimento di miRNAs dalle MVs alle cellule target.
Successivamente a questi studi, si è tentato di capire quanto in un processo rigenerativo possa essere imputato alle MVs e quanto ai fattori solubili presenti nel CM e, a questo proposito, è stata valutata l’abilità delle MVs di inibire la proliferazione delle cellule periferiche mononucleate del sangue (PBMC). La loro azione è stata comparata a quello del CM e del sovranatante (SN) ottenuto dal CM dopo scorporazione delle MVs. Il CM ed il SN hanno manifestato capacità immunosoppressiva ma, anche dopo un trattamento di sonicazione al fine del rilascio del loro contenuto, le MVs non hanno dimostrato quest’abilità. Questi risultati portano a dedurre che le MVs sono in grado di trasportare informazioni alle cellule target attraverso molecole capaci di contrastare l'effetto infiammatorio dovuto all'uso di LPS ma, tenendo in considerazione la mancanza di effetto immunomodulatorio, probabilmente in vivo la loro azione è integrata anche dalla presenza dei fattori solubili presenti nel CM.
I meccanismi paracrini materno-fetali sono di vitale importanza ai fini dell’instaurarsi di una gravidanza, per cui si è ritenuto interessante studiare questi meccanismi durante la produzione in vitro di embrioni bovini. Le differenti componenti del secretoma (CM, SN e MVs) ottenute da AMCs ed EDCs bovine sono state aggiunte al terreno di coltura embrionale a differenti giorni di coltura. I risultati hanno dimostrato che il giorno 5 è il migliore momento per la supplementazione e che le MVs di AMCs portano a migliori risultati qualitativi. Questi dati sono stati confermati dalla valutazione di alcuni geni coinvolti nell'apoptosi e nella protezione contro specie reattive dell'ossigeno. I motivi per i quali le MVs di AMCs si siano dimostrate migliori di quelle secrete dalle EDCs non sono ancora conosciuti ma è probabile che le EDCs coltivate in monostrato in vitro vadano incontro a de-differenziamento che altera la qualità del loro secreto.
In conclusione, è possibile affermare che le AMCs sono una linea cellulare affascinante in quanto derivano da materiale di scarto biologico, e quindi a basso costo, e possono essere impiegate in medicina rigenerativa per la loro capacità di trasportare informazioni alle cellule target. Le MVs possono offrire un nuovo strumento terapeutico privo di cellule nell’ambito della nanomedicina.During this PhD project, studies were carried out to understand the ability of amniotic mesenchymal cells (AMCs) to act by paracrine mechanism. At first, AMCs and their conditioned medium (CM) were investigated in an in vitro model using equine endometrial cells (EDCs) as target. Proliferation of EDCs was studied co-culturing them with AMCs in a trans-well system or in presence of AMC-CM. In both conditions, there was a significant increase in EDC proliferation rate, defining the crucial role of factors secreted by AMCs in stem cells action. CM is composed of soluble factors and no-soluble factors as microvesicles (MVs). In this context, in the second step of this project, the presence and the type of AMC-MVs were identified to understand their role in regenerative medicine. The production of MVs was optimized through a CM ultracentrifugation at 100.000 g for 1 hour. Microvesicle production from equine AMCs was 2550±71 particles/cell, with a mean dimension of 258±55 nm. The transmission electron microscopy confirmed the presence of extra-cellular vesicles that were classified as shedding vesicles for their size and modality of secretion. In order to understand if endometrial cells (EDCs) tendon cells (TNCs) were target of these MVs, an incorporation study was performed labelling MVs with a lipophilic fluorochrome such as PKH-26. By a dose-response curve, the optimal conditions of incorporation were at 72 h at a concentration of 40x106 MVs/ml for EDCs, and at 24-72 h at a concentration of 40x106 MVs/ml for TNCs. In order to study MVs ability to counteract an in vitro inflammation, EDCs and TNCs challenged with LPS and treated with MVs were evaluated by viability cell tests, by expression of some pro-inflammatory genes, and by release of respective cytokines. For both cell types, the apoptosis rate increased dramatically in cells treated with LPS if compared to the control (CTR). LPS significantly upregulated the expression of TNF-α, IL-6 and IL-1β in EDCs and of MMP-1, MMP-9, MMP-13 and TNF-α in TNCs. MVs were able to counteract the action of LPS, decreasing the apoptosis rate and reducing in the expression levels of the pro-inflammatory genes in both cell lines. Coherent results were obtained through the analysis of pro-inflammatory (TNF-β and IL-6) and anti-inflammatory (TGF-α) cytokines released by EDCs in the culture medium, confirming the ability of MVs to transport molecules able to counteract the stress induced by LPS. Since MVs contain various active molecules, the presence of three miRNAs (miR-335, miR-146a, and miR-26a-2) was investigated, as they are involved in the regulation of inflammation. The selected miRNAs have been found in both AMCs and their MVs, so the previously observed downregulation of gene expression could be correlated to miRNA transfer from MVs to target cells. Moreover, the ability of MVs to inhibit peripheral blood mononuclear cell (PBMC) was evaluated, but MVs, also after lysis by sonication to release their content, were not able to inhibit PBMC proliferation despite to CM and SN. These results led to hypothesize that MVs brought to the target cells some molecules able to counteract the inflammatory situation due to the LPS but, taking into account the lack of their immunomodulatory action, probably, for an in vivo healing, soluble factor of CM are necessary too. Paracrine mechanism are essential also in maternal-fetal communication. In this context, we studied these mechanisms during bovine in vitro embryo production. Different components of secretome (CM, SN and MVs) from bovine AMCs and EDCs were supplemented to the embryo culture media at different days of culture. The results demonstrated that the day 5 of culture is the best time point for the supplementation of these components and that AMCs-MVs provided the best environment for the embryo concerning the blastocyst quality. These data were confirmed by the evaluation of genes involved in apoptosis and reactive oxygen species protection. The reasons for which the MVs of AMCs have proved better than those secreted by EDCs are not yet known but it is likely that in vitro culture of EDCs in monolayer may induce a de-differentiation that alters the quality of their secretion. As conclusion of this project, it is possible to speculate that AMCs are fascinating in view of producing off-the-shelf products, at low cost, and their use in regenerative medicine for their capacity to carry information to the target cells. The MVs may offer a new therapeutic cell-free tool in nanomedicine.
Livres sur le sujet "Reproductive cell"
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Tilly, Jonathan L., Jerome F. Strauss et Martin Tenniswood, dir. Cell Death in Reproductive Physiology. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-1944-6.
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1962-, Tilly Jonathan L., Strauss Jerome F. 1947-, Tenniswood M, Serono Symposia USA et International Symposium on Cell Death in Reproductive Physiology (1996 : Chicago, Ill.), dir. Cell death in reproductive physiology. New York : Springer-Verlag, 1997.
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Scott, Christopher Thomas. Stem Cell Now. New York : Penguin Group USA, Inc., 2008.
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Scott, Christopher Thomas. The stem cell : Science, ethics, politics. Englewood, Colo : Roberts and Co., 2006.
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Loke, Y. W. Human implantation : Cell biology and immunology. Cambridge : Cambridge University Press, 1995.
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del, Mazo Jesús, et Workshop on Reproductive Toxicology (1997 : Granada, Spain), dir. Reproductive toxicology : In vitro germ cell developmental toxicology, from science to social and industrial demand. New York : Plenum Press, 1998.
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Mazo, Jesús. Reproductive toxicology : In vitro germ cell developmental toxicology, from science to social and industrial demand. New York : Springer, 1998.
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Stem cell now : From the experiment that shook the world to the new politics of life. New York : Pi Press, 2006.
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Symposium, on Biology of Reproduction and Cell Motility in Plants and Animals (1986 Siena Italy). Biology of reproduction and cell motility in plants and animals : Proceedings of the Symposium on : Biology of Reproduction and Cell Motility in Plants and Animals, Siena, Italy, April 7-8, 1986. Siena, Italy : University of Siena, 1986.
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The biology of cell reproduction. Cambridge, Mass : Harvard University Press, 1985.
Trouver le texte intégralChapitres de livres sur le sujet "Reproductive cell"
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Fahey, John V., Charu Kaushic et Charles R. Wira. « Human Uterine Epithelial Cells : Influence of culture conditions and stromal cells on epithelial cell transepithelial cell resistance ». Dans Reproductive Immunology, 366–78. Dordrecht : Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4197-0_38.
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Lawit, Shai J., et Mark A. Chamberlin. « Transgenic Reproductive Cell Ablation ». Dans Methods in Molecular Biology, 377–86. New York, NY : Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7286-9_28.
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Peluso, John J. « Cell-to-Cell Contact and the Role of Cadherins Cell Survival ». Dans Cell Death in Reproductive Physiology, 111–24. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-1944-6_11.
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Rapley, Elizabeth A. « Susceptibility Alleles for Testicular Germ Cell Tumor ». Dans Male Reproductive Cancers, 317–35. New York, NY : Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-0449-2_11.
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Nathanson, Katherine L. « Molecular Genetics of Testicular Germ Cell Tumor ». Dans Male Reproductive Cancers, 181–99. New York, NY : Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-0449-2_6.
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Pesce, Maurizio, Maria Grazia Farrace, Alessandra Amendola, Mauro Piacentini et Massimo De Felici. « Stem Cell Factor Regulation of Apoptosis in Mouse Primordial Germ Cells ». Dans Cell Death in Reproductive Physiology, 19–31. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-1944-6_3.
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Chedrese, Pedro J., et Alejandro M. Bertorello. « The Molecules That Transmit Information into the Cell : The Intracellular Signaling Pathways ». Dans Reproductive Endocrinology, 23–39. Boston, MA : Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-88186-7_3.
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Ansell, I. D. « Testis — Non-Germ Cell Tumours ». Dans Atlas of Male Reproductive Pathology, 41–44. Dordrecht : Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4868-6_8.
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Tilly, Jonathan L., et Kim I. Tilly. « Dissecting the Functions, Mechanisms, and Genes of Physiological Cell Death in Reproductive Tissues : An Overview ». Dans Cell Death in Reproductive Physiology, 1–7. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-1944-6_1.
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Schomberg, David W., et Jonathan L. Tilly. « Regulation of Apoptosis Versus Mitosis in Immature Granulosa Cells ». Dans Cell Death in Reproductive Physiology, 103–10. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-1944-6_10.
Texte intégralActes de conférences sur le sujet "Reproductive cell"
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Vlašković, Veljko. « Pravni značaj biomedicinske usluge čuvanja reproduktivnih ćelija maloletnog lica ». Dans XVI Majsko savetovanje. University of Kragujevac, Faculty of Law, 2020. http://dx.doi.org/10.46793/upk20.451v.
Texte intégralRésumé :
Serbian Law on Medically Assisted Reproduction has widened the number of persons who enjoy the right to preserve their reproductive material for postponed reproduction due to threatened infertility. In this context, that right now belongs also to underage person if her/his parents gave the explicit and written consent to harvesting, freezing and banking of their child's reproductive cells. These are the cases when the underage person currently has reproductive capability, but she/ he is threatened by loss of reproductive function in the near future due to developing illness or forthcoming medical treatment. Understandably, the child has no right to postponed usage of residual reproductive cells beyond the cases of threatened infertility, since the underage person does not meet the legal requirements concerning personal and family status necessary for enjoying services of medically assisted reproduction. Frozen reproductive cells of underage persons will be stored without time limits, but the underage person cannot use them for conception before acquisition of legal conditions to enjoy the services of medically assisted reproduction (majority and full legal capacity, conclusion of marriage or establishing cohabitation). Such approach intends to make balance between the interests of an underage person whose gametes are stored and the „the best interets of the prospective child“ who should be conceived and born. Frozen reproductive cells of an underage person cannot be used in any other purpose except postponed homologous reproduction. Although it is not directly mentioned in Law on Medically Assisted Reproduction, reproductive cells may be harvested from an underage persons if she/he does not object to it. Such rule derives from the analogous application to the rule of Law on Human Cells and Tissues that human cell cannot be harvested from a person who has not attained majority if such person objects to it. Parents of the child decide on giving consent to harvesting, freezing and banking of their child's reproductive cells by their mutual agreement, which has the legal significance of the issue that greatly affects the child's life. The absence of consent of one or both parents cannot be replaced by state authority decision. Furthermore, the parents are not allowed to revoke their consent to their child's gamete banking.
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Vlašković, Veljko. « Pravni značaj biomedicinske usluge čuvanja reproduktivnih ćelija maloletnog lica ». Dans XVI Majsko savetovanje. University of Kragujevac, Faculty of Law, 2020. http://dx.doi.org/10.46793/upk20.451v.
Texte intégralRésumé :
Serbian Law on Medically Assisted Reproduction has widened the number of persons who enjoy the right to preserve their reproductive material for postponed reproduction due to threatened infertility. In this context, that right now belongs also to underage person if her/his parents gave the explicit and written consent to harvesting, freezing and banking of their child's reproductive cells. These are the cases when the underage person currently has reproductive capability, but she/ he is threatened by loss of reproductive function in the near future due to developing illness or forthcoming medical treatment. Understandably, the child has no right to postponed usage of residual reproductive cells beyond the cases of threatened infertility, since the underage person does not meet the legal requirements concerning personal and family status necessary for enjoying services of medically assisted reproduction. Frozen reproductive cells of underage persons will be stored without time limits, but the underage person cannot use them for conception before acquisition of legal conditions to enjoy the services of medically assisted reproduction (majority and full legal capacity, conclusion of marriage or establishing cohabitation). Such approach intends to make balance between the interests of an underage person whose gametes are stored and the „the best interets of the prospective child“ who should be conceived and born. Frozen reproductive cells of an underage person cannot be used in any other purpose except postponed homologous reproduction. Although it is not directly mentioned in Law on Medically Assisted Reproduction, reproductive cells may be harvested from an underage persons if she/he does not object to it. Such rule derives from the analogous application to the rule of Law on Human Cells and Tissues that human cell cannot be harvested from a person who has not attained majority if such person objects to it. Parents of the child decide on giving consent to harvesting, freezing and banking of their child's reproductive cells by their mutual agreement, which has the legal significance of the issue that greatly affects the child's life. The absence of consent of one or both parents cannot be replaced by state authority decision. Furthermore, the parents are not allowed to revoke their consent to their child's gamete banking.
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Leshkova, I. V., O. V. Dolgih et O. YU Ustinova. « IMMUNOLOGICAL DISORDERS OF THE REPRODUCTIVE SYSTEM THAT OCCUR WHEN EXPOSED TO BENZENE, IN EMPLOYEES OF OIL-PRODUCING ENTERPRISES ». Dans The 16th «OCCUPATION and HEALTH» Russian National Congress with International Participation (OHRNC-2021). FSBSI “IRIOH”, 2021. http://dx.doi.org/10.31089/978-5-6042929-2-1-2021-1-313-316.
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Abstract. Introduction. The protection of the reproductive health of the working-age population is the most important direction of State policy. In 5-15% of cases, the causes of reproductive dysfunction are immunological disorders. Benzene belongs to the group of industrial reprotoxicants, however, its effect of benzene on the reproductive system has not been sufficiently studied. Objective: to study the immunological aspects of the effect of benzene on the reproductive system. Methods. We examined 50 men exposed to benzene with reproductive disorders (26-49 years old), as well as 4 workers with normal sexual function aged 53-60 years. Spontaneous and induced changes in the cellular expression of apoptosis markers were studied. For the study, the ANNEXIN V-FITC/7-AAD kit was used for the detection of cells that have undergone apoptosis. The experiment was conducted in vitro using a biological medium (ejaculate). A factor of the chemical nature was benzene. Results. According to the results of the comparative analysis, there were no significant deviations of pathogenetic tests of immunological markers in comparison with the reference level in the spontaneous expression samples, but there was an excess of expression of the CD95 + cell death receptor (p<0.05) in 30% of the samples examined, and a decrease in the number of Annexin V-FITC+7AAD negative cells (without reaching the significance level) in samples with a load of (15%). There was a difference in the expression levels of CD95+ and CD25+ CD-reception indicators by 20% and 10% in relation to the spontaneous level (p<0.05). Representatives of the chemical group of aromatic hydrocarbons realize reprotoxicity, using the mechanism of excessive induction of the membrane signaling of the cell death receptor, accelerate the natural program of cell death by approximately 20% compared to the state of reproductive cells that were not stimulated. Conclusion. At the present stage, one of the tasks of occupational medicine is to study the effect of chemicals on the processes of reproduction, to develop new approaches to assessing the risk of their impact on the reproductive health of workers.
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Tuğlu, Ibrahim. « The Role of Stem Cell on The Reproductive organs ». Dans 15th International Congress of Histochemistry and Cytochemistry. Istanbul : LookUs Scientific, 2017. http://dx.doi.org/10.5505/2017ichc.op-41.
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A.A., Matrosov, Nizhnik D.A. et Soloviev A.N. « DIFFUSION OF A CRYOPROTECTANT THROUGH THE MEMBRANE OF REPRODUCTIVE CELLS ». Dans OF THE ANNIVERSARY Х INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE «INNOVATIVE TECHNOLOGIES IN SCIENCE AND EDUCATION» («ITSE 2022» CONFERENCE). DSTU-Print, 2022. http://dx.doi.org/10.23947/itse.2022.124-126.
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In order to develop a new technology for low-temperature preservation of fish reproductive cells, and sturgeon fish in particular, mathematical modeling of acoustic impact on biological objects has been performed. A mathematical model of cryoprotectant diffusion through the reproductive cell membrane is constructed. It is assumed that a special piezoactuator creates an acoustic field in the cryoprotectant. By virtue of this, the corresponding velocity field of the environment is assumed to be set. The resulting boundary value problem is solved numerically using the finite element method.
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Liu, Yehe, Shi Gu, Michiko Watanabe, Andrew M. Rollins et Michael W. Jenkins. « Cell counting in whole mount tissue volumes using expansion OCT (Conference Presentation) ». Dans Diagnosis and Treatment of Diseases in the Breast and Reproductive System III, sous la direction de Melissa C. Skala et Paul J. Campagnola. SPIE, 2017. http://dx.doi.org/10.1117/12.2253162.
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V.P., Osipova, et Kolyada M.N. « APPLICATION OF NEW GENERATION ANTIOXIDANTS AS CRYOPROTECTORS IN LOWTEMPERATURE PRESERVATION OF STURGEON REPRODUCTIVE CELLS ». Dans II INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "DEVELOPMENT AND MODERN PROBLEMS OF AQUACULTURE" ("AQUACULTURE 2022" CONFERENCE). DSTU-Print, 2022. http://dx.doi.org/10.23947/aquaculture.2022.103-105.
Texte intégralRésumé :
The paper presents the results of a study of the cryoprotective activity of a new generation of antioxidants – hybrid multifunctional phenolic derivatives during low-temperature preservation of sturgeon reproductive cells. It has been shown that the addition of phosphorus-containing sterically hindered phenol, pyrrolidine and thioacetamide phenolic derivatives to the basic modified Stein cryoprotective medium, makes it possible to increase the low cryoresistance of sturgeon sperm: the level of lipid peroxidation decreases, cell motility improves, and the fertility of defrosted sperm increases. The effectiveness of the cryoprotective action of new antioxidants that can affect different stages and links of oxidative cryostress exceeds the activity of known antioxidants (Ionol and Trolox).
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Li, Yang. « IDDF2021-ABS-0033 Protective effects of female reproductive factors on gastric signet ring cell carcinoma ». Dans Abstracts of the International Digestive Disease Forum (IDDF), Hong Kong, 4–5 September 2021. BMJ Publishing Group Ltd and British Society of Gastroenterology, 2021. http://dx.doi.org/10.1136/gutjnl-2021-iddf.12.
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Lesèche, G., G. Tobelem, J. Caen et B. Andreassian. « ADULT HUMAN SAPHENOUS VEIN ENDOTHELIAL CELLS : ASSESMENT OF THEIR REPRODUCTIVE CAPACITY AND FUNCTIONAL INTEGRITY PRIOR TO IMPLANTATION ON A VASCULAR GRAFT ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643359.
Texte intégralRésumé :
Establishment of an intact functioning endothelial monolayer on a graft, at or near the time of implantation might be one of the ultimate requirement to get a biocompatible intravascular prosthesis. Following this hypothesis, endothelial cells from human stripped varicose veins were harvested with collagenase and grown on a human fibronectin matrix. The cultured cells (either in primary culture or throughout their lifespan in culture, 1 to 10 passages) exhibited characteristic cobblestone morphology and consistently displayed immunofluorescent staining for factor VUI-related antigen. Functional integrity of this endothelial cells was assayed by their ability to produce prostacyclin. After 15 minutes stimulation with 1 U/ml thrombin, production of 6 Keto PGF1α determined by Elisa was 17 ± 1.2 ng/106 cells. Proliferation was investigated in defined medium supplemented with various concentrations of serum (5 up Jto 30 %), ECGS (25 up to 150 μg/ml) and heparin (10−8 to 10−5M). Optimal growth required both, 100 μg/ml ECGS and 10−5M heparin, under these conditions cells culture achieved cell densities at confluence of 1.2 105 cells per square centimeter with doubling times of one day. Using I-heparin. a binding was demonstrated with an apparent Kd of 0.35 × 10−6 M. After characterization according to morphological, proliferative and functional criteria., cells were freezed at −80°C and ultimately used to coat polytetrafluoro-ethylene grafts (PTFE) which are currently used for vascular reconstructive surgery . Protein-treated material did allow cell attachment and growth to a confluent monolayer as assayed by light and scanning electron microscopy.These data suggested that i) stripped varicose veins provide a readily available source of adult human endothelial cell, ii) these cells grow vigorously in long-term culture when both ECGS and heparin are added to the culture medium, iii) they can adhere and grow to a confluent monolayer on vascular graft prior to implantation, iv) lining graft materials in vitro may be useful in improving the performance of small caliber vascular grafts according to prostacyclin production and surface bound heparin of these cells.
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Lu, Yani, Jianning Luo, Sophia Wang, Jane Sullivan-Halley, Wendy Cozen et Leslie Bernstein. « Abstract 867 : Reproductive factors and risk of B-cell non-Hodgkin lymphoma among women in Los Angeles ». Dans Proceedings : AACR 106th Annual Meeting 2015 ; April 18-22, 2015 ; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-867.
Texte intégralRapports d'organisations sur le sujet "Reproductive cell"
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Daley, George. Ovarian Cancer and Reproductive System Biology : A Harvard Stem Cell Institution Consortium. Fort Belvoir, VA : Defense Technical Information Center, décembre 2010. http://dx.doi.org/10.21236/ada542144.
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Heifetz, Yael, et Michael Bender. Success and failure in insect fertilization and reproduction - the role of the female accessory glands. United States Department of Agriculture, décembre 2006. http://dx.doi.org/10.32747/2006.7695586.bard.
Texte intégralRésumé :
The research problem. Understanding of insect reproduction has been critical to the design of insect pest control strategies including disruptions of mate-finding, courtship and sperm transfer by male insects. It is well known that males transfer proteins to females during mating that profoundly affect female reproductive physiology, but little is known about the molecular basis of female mating response and no attempts have yet been made to interfere with female post-mating responses that directly bear on the efficacy of fertilization. The female reproductive tract provides a crucial environment for the events of fertilization yet thus far those events and the role of the female tract in influencing them are poorly understood. For this project, we have chosen to focus on the lower reproductive tract because it is the site of two processes critical to reproduction: sperm management (storage, maintenance, and release from storage) and fertilization. E,fforts during this project period centered on the elucidation of mating responses in the female lower reproductive tract The central goals of this project were: 1. To identify mating-responsive genes in the female lower reproductive tract using DNA microarray technology. 2. In parallel, to identify mating-responsive genes in these tissues using proteomic assays (2D gels and LC-MS/MS techniques). 3. To integrate proteomic and genomic analyses of reproductive tract gene expression to identify significant genes for functional analysis. Our main achievements were: 1. Identification of mating-responsive genes in the female lower reproductive tract. We identified 539 mating-responsive genes using genomic and proteomic approaches. This analysis revealed a shift from gene silencing to gene activation soon after mating and a peak in differential gene expression at 6 hours post-mating. In addition, comparison of the two datasets revealed an expression pattern consistent with the model that important reproductive proteins are pre-programmed for synthesis prior to mating. This work was published in Mack et al. (2006). Validation experiments using real-time PCR techniques suggest that microarray assays provide a conservativestimate of the true transcriptional activity in reproductive tissues. 2.lntegration of proteomics and genomics data sets. We compared the expression profiles from DNA microarray data with the proteins identified in our proteomic experiments. Although comparing the two data sets poses analyical challenges, it provides a more complete view of gene expression as well as insights into how specific genes may be regulated. This work was published in Mack et al. (2006). 3. Development of primary reproductive tract cell cultures. We developed primary cell cultures of dispersed reproductive tract cell types and determined conditions for organ culture of the entire reproductive tract. This work will allow us to rapidly screen mating-responsive genes for a variety of reproductive-tract specifi c functions. Scientific and agricultural significance. Together, these studies have defined the genetic response to mating in a part of the female reproductive tract that is critical for successful fertllization and have identified alarge set of mating-responsive genes. This work is the first to combine both genomic and proteomic approaches in determining female mating response in these tissues and has provided important insights into insect reproductive behavior.
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Ohad, Nir, et Robert Fischer. Control of Fertilization-Independent Development by the FIE1 Gene. United States Department of Agriculture, août 2000. http://dx.doi.org/10.32747/2000.7575290.bard.
Texte intégralRésumé :
A fundamental problem in biology is to understand how fertilization initiates reproductive development. During plant reproduction, one sperm cell fuses with the egg to form an embryo, whereas a second sperm cell fuses with the adjacent central cell nucleus to form the endosperm tissue that supports embryo and/or seedling development. To understand the mechanisms that initiate reproduction, we have isolated mutants of Arabidopsis that allow for replication of the central cell and subsequent endosperm development without fertilization. In this project we have cloned the MEA gene and showed that it encode a SET- domain polycomb protein. Such proteins are known to form chromatin-protein complexes that repress homeotic gene transcription and influence cell proliferation from Drosophylla to mammals. We propose a model whereby MEA and an additional polycomb protein we have cloned, FIE , function to suppress a critical aspect of early plant reproduction and endosperm development, until fertilization occurs. Using a molecular approach we were able to determine that FIE and MEA interact physically, suggesting that these proteins have been conserved also during the evolution of flowering plants. The analysis of MEA expression pattern revealed that it is an imprinted gene that displays parent-of- origin-dependent monoallelic expression specifically in the endosperm tissue. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds support the parental conflict theory for the evolution of imprinting in plants and mammals. These results contribute new information on the initiation of endosperm development and provide a unique entry point to study asexual reproduction and apomixis which is expected to improve crop production.
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz et Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, février 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
Texte intégralRésumé :
The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.
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Newton, Ronald, Joseph Riov et John Cairney. Isolation and Functional Analysis of Drought-Induced Genes in Pinus. United States Department of Agriculture, septembre 1993. http://dx.doi.org/10.32747/1993.7568752.bard.
Texte intégralRésumé :
Drought is a common factor limiting timber production in the U.S. and Israel. Loblolly (Pinus taeda) and alleppo pine (Pinus halepensis) seedling survival is reduced when out planted, and growth and reproduction are often hindered by periodic droughts during later stages of tree development. Molecular and gene responses to drought stress have not been characterized. The objectives were to characterize drought-induced gene clones from these pines, to determine the effects of a growth regulator on drought tolerance, ABA levels, and drought-induced gene expression in alleppo pine, and to develop procedures for loblolly pine transformation. Nearly 20 cDNA clones influenced by gradual, prolonged drought stress have been isolated. Many of these have been shown to be induced by drought stress, whereas several others are down-regulated. These are the first drought-induced genes isolated from a pine species. Two genomic clones (lp5-1 and lp3-1) have been sequenced and characterized, and each has been found to be associated with a gene family. Clone lp5 appears to code for a cell wall protein, and clone lp3 codes for a nuclear protein. The former may be associated with changing the elastic properties of the cell wall, while the latter may be involved in signal transduction and/or protection from desiccation in the nucleus. Clone lp3 is similar to a drought-induced gene from tomato and is regulated by ABA. Several DNA sequences that are specific to induction during growth-retardation in alleppo pine by uniconazole have been identified. The active DNA species is now being identified. Promoters from genomic clones, lp3 and lp5, have been sequenced. Both are functional when fused with the gus reporter gene and transferred to other plant tissues as well as responding to a simulated drought stress. Through exodeletion analysis, it has been established that the promoter ABRE element of lp3 responds to ABA and that drought-induction of lp3 expression may also involve ABA. Stable tobacco transformants carrying either the lp5 or the lp3 promoter fused to a reporter gus gene have been obtained. The lp5lgus fusion was expressed at several stages of tobacco development and differentiation including the reproductive stage. There was no difference in phenotype between the transformants and the wild type. Embryogenesis procedures were developed for slash pine, but attempts to couple this process with gene transfer and plantlet transformation were not successful. Transformation of pine using Agrobacterium appears tractable, but molecular data supporting stable integration of the Agrobacterium-transferred gene are still inconclusive.
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Wolfenson, David, William W. Thatcher, Rina Meidan, Charles R. Staples et Israel Flamenbaum. Hormonal and Nutritional Stretegies to Optimize Reproductive Function and Improve Fertility of Dairy Cattle during Heat Stress in Summer. United States Department of Agriculture, août 1994. http://dx.doi.org/10.32747/1994.7568773.bard.
Texte intégralRésumé :
The BARD program includes two main parts. In the first, experiments were conducted to complete our understanding of the mechanisms responsible for the impairment of reproductive functions under heat stress. Experiments focused on follicular development and function, since results obtained in our previous BARD project indicate that the preovulatory follicle is susceptible to heat stress. The theca cells, sensitive to thermal stress, produced less androgen during the summer, as well as during the autumn. Similarly, luteinized theca cells obtained from cows in summer produced much less progesterone than in winter. Granulosa cells and luteinized granulosa cells were less susceptible to heat stress. A delayed effect of heat stress on follicular development, on suppression of dominance and on steroid production by theca and granulosa cells was noted. This may be related to the low fertility of cows during the cool months of autumn. In the second part, experiments were conducted aiming to improve fertility in summer. The timed AI program was developed using two injections of GnRH coupled with PGF2a. It was found effective in improving reproductive performance in lactating cows. Limitations induced by heat stress on estrus detection were eliminated with the timed AI management program. Replacing the second injection of GnRH with hCG instead of GnRH agonist increased plasma progesterone levels post ovulation but did not improve fertility. Use of the timed AI program in summer, shortened days open and increased the net revenue per cow, however, it did not protect the embryo fiom temperature-induced embryonic mortality. Incorporation of a GnRH-agonist implant into the timed AJ program was examined. The implant increased plasma progesterone and LH concentrations and altered follicular dynamics. The use of a GnRH-implant enhanced pregnancy rate in cows with low body conditions. In a timed embryo transfer experiment, the use of fresh or frozen in vitro produced embryos was compared in the summer to improve fertility. The use of flesh embryos (but not frozen ones) improved pregnancy rate, however, substantial embryonic death occurred between 21 and 45 days. The timed AI program, which is now being used commercially, shortened days open, and increased pregnancy rate during summer. Other approaches which were found to improve fertility in small-scale studies, need to be tested again in large-scale field trials.
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Christenson, Erleen. Effect of copper on cell division, nitrogen metabolism, morphology, and sexual reproduction in the life cycle of Closterium moniliferum (Chlorophyceae). Portland State University Library, janvier 2000. http://dx.doi.org/10.15760/etd.54.
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Ohad, Nir, et Robert Fischer. Regulation of Fertilization-Independent Endosperm Development by Polycomb Proteins. United States Department of Agriculture, janvier 2004. http://dx.doi.org/10.32747/2004.7695869.bard.
Texte intégralRésumé :
Arabidopsis mutants that we have isolated, encode for fertilization-independent endosperm (fie), fertilization-independent seed2 (fis2) and medea (mea) genes, act in the female gametophyte and allow endosperm to develop without fertilization when mutated. We cloned the FIE and MEA genes and showed that they encode WD and SET domain polycomb (Pc G) proteins, respectively. Homologous proteins of FIE and MEA in other organisms are known to regulate gene transcription by modulating chromatin structure. Based on our results, we proposed a model whereby both FIE and MEA interact to suppress transcription of regulatory genes. These genes are transcribed only at proper developmental stages, as in the central cell of the female gametophyte after fertilization, thus activating endosperm development. To test our model, the following questions were addressed: What is the Composition and Function of the Polycomb Complex? Molecular, biochemical, genetic and genomic approaches were offered to identify members of the complex, analyze their interactions, and understand their function. What is the Temporal and Spatial Pattern of Polycomb Proteins Accumulation? The use of transgenic plants expressing tagged FIE and MEA polypeptides as well as specific antibodies were proposed to localize the endogenous polycomb complex. How is Polycomb Protein Activity Controlled? To understand the molecular mechanism controlling the accumulation of FIE protein, transgenic plants as well as molecular approaches were proposed to determine whether FIE is regulated at the translational or posttranslational levels. The objectives of our research program have been accomplished and the results obtained exceeded our expectation. Our results reveal that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms (Publication 1). Moreover our data show that FIE has additional functions besides controlling the development of the female gametophyte. Using transgenic lines in which FIE was not expressed or the protein level was reduced during different developmental stages enabled us for the first time to explore FIE function during sporophyte development (Publication 2 and 3). Our results are consistent with the hypothesis that FIE, a single copy gene in the Arabidopsis genome, represses multiple developmental pathways (i.e., endosperm, embryogenesis, shot formation and flowering). Furthermore, we identified FIE target genes, including key transcription factors known to promote flowering (AG and LFY) as well as shoot and leaf formation (KNAT1) (Publication 2 and 3), thus demonstrating that in plants, as in mammals and insects, PcG proteins control expression of homeobox genes. Using the Yeast two hybrid system and pull-down assays we demonstrated that FIE protein interact with MEA via the N-terminal region (Publication 1). Moreover, CURLY LEAF protein, an additional member of the SET domain family interacts with FIE as well. The overlapping expression patterns of FIE, with ether MEA or CLF and their common mutant phenotypes, demonstrate the versatility of FIE function. FIE association with different SET domain polycomb proteins, results in differential regulation of gene expression throughout the plant life cycle (Publication 3). In vitro interaction assays we have recently performed demonstrated that FIE interacts with the cell cycle regulatory component Retinobalsoma protein (pRb) (Publication 4). These results illuminate the potential mechanism by which FIE may restrain embryo sac central cell division, at least partly, through interaction with, and suppression of pRb-regulated genes. The results of this program generated new information about the initiation of reproductive development and expanded our understanding of how PcG proteins regulate developmental programs along the plant life cycle. The tools and information obtained in this program will lead to novel strategies which will allow to mange crop plants and to increase crop production.
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Kaboré, Gisele, et Idrissa Kabore. Analyse secondaire des données de l'analyse situationnelle des services de santé de la reproduction. Population Council, 2009. http://dx.doi.org/10.31899/pgy20.1000.
Texte intégralRésumé :
En début 2002, l’UNFPA a soutenu un projet intitulé Renforcement des services sanitaires et sociaux pour faire face aux besoins de santé sexuelle et reproductive des adolescentes. Le projet avait pour objectif d’améliorer la connaissance des adolescentes mariées en ce qui concerne la législation et leurs propres droits; les éduquer à prendre soin de leur propre santé et de celle de leurs enfants; et augmenter leur accessibilité aux services de santé reproductive, particulièrement dans les régions les plus pauvres du Burkina Faso. Le projet a affirmé que les normes de fonctionnement ne sont pas remplies en termes d’infrastructures, d’équipement, de matériel et de ressources humaines. Les services disponibles ne sont pas bien connus par les populations, ce qui peut limiter la fréquentation. Il apparaît aussi que les services offerts aux adolescents ne sont pas assez développés car peu de prestataires ont des compétences nécessaires. Quelques recommandations ont été formulées en réponses aux problèmes et aux insuffisances constatées, sur la capacité d’offre et la qualité des services.
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Ohad, Nir, et Robert Fischer. Regulation of plant development by polycomb group proteins. United States Department of Agriculture, janvier 2008. http://dx.doi.org/10.32747/2008.7695858.bard.
Texte intégralRésumé :
Our genetic and molecular studies have indicated that FIE a WD-repeat Polycomb group (PcG) protein takes part in multi-component protein complexes. We have shown that FIE PcG protein represses inappropriate programs of development during the reproductive and vegetative phases of the Arabidopsis life cycle. Moreover, we have shown that FIE represses the expression of key regulatory genes that promote flowering (AG and LFY), embryogenesis (LEC1), and shoot formation (KNAT1). These results suggest that the FIE PcG protein participates in the formation of distinct PcG complexes that repress inappropriate gene expression at different stages of plant development. PcG complexes modulate chromatin compactness by modifying histones and thereby regulate gene expression and imprinting. The main goals of our original project were to elucidate the biological functions of PcG proteins, and to understand the molecular mechanisms used by FIE PcG complexes to repress the expression of its gene targets. Our results show that the PcG complex acts within the central cell of the female gametophyte to maintain silencing of MEA paternal allele. Further more we uncovered a novel example of self-imprinting mechanism by the PgG complex. Based on results obtained in the cures of our research program we extended our proposed goals and elucidated the role of DME in regulating plant gene imprinting. We discovered that in addition to MEA,DME also imprints two other genes, FWA and FIS2. Activation of FWA and FIS2 coincides with a reduction in 5-methylcytosine in their respective promoters. Since endosperm is a terminally differentiated tissue, the methylation status in the FWA and FIS2 promoters does not need to be reestablished in the following generation. We proposed a “One-Way Control” model to highlight differences between plant and animal genomic imprinting. Thus we conclude that DEMETER is a master regulator of plant gene imprinting. Future studies of DME function will elucidate its role in processes and disease where DNA methylation has a key regulatory role both in plants and animals. Such information will provide valuable insight into developing novel strategies to control and improve agricultural traits and overcome particular human diseases.