Thematische Bibliographien / Acquisition of cell identity

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Auswahl der wissenschaftlichen Literatur zum Thema „Acquisition of cell identity“

Autor: Grafiati

Veröffentlicht am 25. Mai 2024

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Zeitschriftenartikel zum Thema "Acquisition of cell identity"

Sylvester, Anne W., Laurie Smith und Michael Freeling. „ACQUISITION OF IDENTITY IN THE DEVELOPING LEAF“. Annual Review of Cell and Developmental Biology 12, Nr. 1 (November 1996): 257–304. http://dx.doi.org/10.1146/annurev.cellbio.12.1.257.

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Mesman, Simone, und Marten P. Smidt. „Acquisition of the Midbrain Dopaminergic Neuronal Identity“. International Journal of Molecular Sciences 21, Nr. 13 (30.06.2020): 4638. http://dx.doi.org/10.3390/ijms21134638.

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The mesodiencephalic dopaminergic (mdDA) group of neurons comprises molecularly distinct subgroups, of which the substantia nigra (SN) and ventral tegmental area (VTA) are the best known, due to the selective degeneration of the SN during Parkinson’s disease. However, although significant research has been conducted on the molecular build-up of these subsets, much is still unknown about how these subsets develop and which factors are involved in this process. In this review, we aim to describe the life of an mdDA neuron, from specification in the floor plate to differentiation into the different subsets. All mdDA neurons are born in the mesodiencephalic floor plate under the influence of both SHH-signaling, important for floor plate patterning, and WNT-signaling, involved in establishing the progenitor pool and the start of the specification of mdDA neurons. Furthermore, transcription factors, like Ngn2, Ascl1, Lmx1a, and En1, and epigenetic factors, like Ezh2, are important in the correct specification of dopamine (DA) progenitors. Later during development, mdDA neurons are further subdivided into different molecular subsets by, amongst others, Otx2, involved in the specification of subsets in the VTA, and En1, Pitx3, Lmx1a, and WNT-signaling, involved in the specification of subsets in the SN. Interestingly, factors involved in early specification in the floor plate can serve a dual function and can also be involved in subset specification. Besides the mdDA group of neurons, other systems in the embryo contain different subsets, like the immune system. Interestingly, many factors involved in the development of mdDA neurons are similarly involved in immune system development and vice versa. This indicates that similar mechanisms are used in the development of these systems, and that knowledge about the development of the immune system may hold clues for the factors involved in the development of mdDA neurons, which may be used in culture protocols for cell replacement therapies.

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Salinno, Cota, Bastidas-Ponce, Tarquis-Medina, Lickert und Bakhti. „β-Cell Maturation and Identity in Health and Disease“. International Journal of Molecular Sciences 20, Nr. 21 (30.10.2019): 5417. http://dx.doi.org/10.3390/ijms20215417.

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The exponential increase of patients with diabetes mellitus urges for novel therapeutic strategies to reduce the socioeconomic burden of this disease. The loss or dysfunction of insulin-producing β-cells, in patients with type 1 and type 2 diabetes respectively, put these cells at the center of the disease initiation and progression. Therefore, major efforts have been taken to restore the β-cell mass by cell-replacement or regeneration approaches. Implementing novel therapies requires deciphering the developmental mechanisms that generate β-cells and determine the acquisition of their physiological phenotype. In this review, we summarize the current understanding of the mechanisms that coordinate the postnatal maturation of β-cells and define their functional identity. Furthermore, we discuss different routes by which β-cells lose their features and functionality in type 1 and 2 diabetic conditions. We then focus on potential mechanisms to restore the functionality of those β-cell populations that have lost their functional phenotype. Finally, we discuss the recent progress and remaining challenges facing the generation of functional mature β-cells from stem cells for cell-replacement therapy for diabetes treatment.

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Kinare, Veena, Archana Iyer, Hari Padmanabhan, Geeta Godbole, Tooba Khan, Zeba Khatri, Upasana Maheshwari, Bhavana Muralidharan und Shubha Tole. „An evolutionarily conserved Lhx2-Ldb1 interaction regulates the acquisition of hippocampal cell fate and regional identity“. Development 147, Nr. 20 (29.09.2020): dev187856. http://dx.doi.org/10.1242/dev.187856.

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ABSTRACTThe protein co-factor Ldb1 regulates cell fate specification by interacting with LIM-homeodomain (LIM-HD) proteins in a tetrameric complex consisting of an LDB:LDB dimer that bridges two LIM-HD molecules, a mechanism first demonstrated in the Drosophila wing disc. Here, we demonstrate conservation of this interaction in the regulation of mammalian hippocampal development, which is profoundly defective upon loss of either Lhx2 or Ldb1. Electroporation of a chimeric construct that encodes the Lhx2-HD and Ldb1-DD (dimerization domain) in a single transcript cell-autonomously rescues a comprehensive range of hippocampal deficits in the mouse Ldb1 mutant, including the acquisition of field-specific molecular identity and the regulation of the neuron-glia cell fate switch. This demonstrates that the LHX:LDB complex is an evolutionarily conserved molecular regulatory device that controls complex aspects of regional cell identity in the developing brain.

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Simon, Françoise, Anne Ramat, Sophie Louvet-Vallée, Jérôme Lacoste, Angélique Burg, Agnès Audibert und Michel Gho. „Shaping of Drosophila Neural Cell Lineages Through Coordination of Cell Proliferation and Cell Fate by the BTB-ZF Transcription Factor Tramtrack-69“. Genetics 212, Nr. 3 (09.05.2019): 773–88. http://dx.doi.org/10.1534/genetics.119.302234.

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Cell diversity in multicellular organisms relies on coordination between cell proliferation and the acquisition of cell identity. The equilibrium between these two processes is essential to assure the correct number of determined cells at a given time at a given place. Using genetic approaches and correlative microscopy, we show that Tramtrack-69 (Ttk69, a Broad-complex, Tramtrack and Bric-à-brac - Zinc Finger (BTB-ZF) transcription factor ortholog of the human promyelocytic leukemia zinc finger factor) plays an essential role in controlling this balance. In the Drosophila bristle cell lineage, which produces the external sensory organs composed by a neuron and accessory cells, we show that ttk69 loss-of-function leads to supplementary neural-type cells at the expense of accessory cells. Our data indicate that Ttk69 (1) promotes cell cycle exit of newborn terminal cells by downregulating CycE, the principal cyclin involved in S-phase entry, and (2) regulates cell-fate acquisition and terminal differentiation, by downregulating the expression of hamlet and upregulating that of Suppressor of Hairless, two transcription factors involved in neural-fate acquisition and accessory cell differentiation, respectively. Thus, Ttk69 plays a central role in shaping neural cell lineages by integrating molecular mechanisms that regulate progenitor cell cycle exit and cell-fate commitment.

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Okada, Yohei, Takuya Shimazaki, Gen Sobue und Hideyuki Okano. „Retinoic-acid-concentration-dependent acquisition of neural cell identity during in vitro differentiation of mouse embryonic stem cells“. Developmental Biology 275, Nr. 1 (November 2004): 124–42. http://dx.doi.org/10.1016/j.ydbio.2004.07.038.

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Conforti, P., D. Besusso, V. D. Bocchi, A. Faedo, E. Cesana, G. Rossetti, V. Ranzani et al. „Faulty neuronal determination and cell polarization are reverted by modulating HD early phenotypes“. Proceedings of the National Academy of Sciences 115, Nr. 4 (08.01.2018): E762—E771. http://dx.doi.org/10.1073/pnas.1715865115.

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Increasing evidence suggests that early neurodevelopmental defects in Huntington’s disease (HD) patients could contribute to the later adult neurodegenerative phenotype. Here, by using HD-derived induced pluripotent stem cell lines, we report that early telencephalic induction and late neural identity are affected in cortical and striatal populations. We show that a large CAG expansion causes complete failure of the neuro-ectodermal acquisition, while cells carrying shorter CAGs repeats show gross abnormalities in neural rosette formation as well as disrupted cytoarchitecture in cortical organoids. Gene-expression analysis showed that control organoid overlapped with mature human fetal cortical areas, while HD organoids correlated with the immature ventricular zone/subventricular zone. We also report that defects in neuroectoderm and rosette formation could be rescued by molecular and pharmacological approaches leading to a recovery of striatal identity. These results show that mutant huntingtin precludes normal neuronal fate acquisition and highlights a possible connection between mutant huntingtin and abnormal neural development in HD.

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Abenza, Juan F., Antonio Galindo, Areti Pantazopoulou, Concha Gil, Vivian de los Ríos und Miguel A. Peñalva. „Aspergillus RabBRab5 Integrates Acquisition of Degradative Identity with the Long Distance Movement of Early Endosomes“. Molecular Biology of the Cell 21, Nr. 15 (August 2010): 2756–69. http://dx.doi.org/10.1091/mbc.e10-02-0119.

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Aspergillus nidulans early endosomes display characteristic long-distance bidirectional motility. Simultaneous dual-channel acquisition showed that the two Rab5 paralogues RabB and RabA colocalize in these early endosomes and also in larger, immotile mature endosomes. However, RabB-GTP is the sole recruiter to endosomes of Vps34 PI3K (phosphatidylinositol-3-kinase) and the phosphatidylinositol-3-phosphate [PI(3)P] effector AnVps19 and rabBΔ, leading to thermosensitivity prevents multivesicular body sorting of endocytic cargo. Thus, RabB is the sole mediator of degradative endosomal identity. Importantly, rabBΔ, unlike rabAΔ, prevents early endosome movement. As affinity experiments and pulldowns showed that RabB-GTP recruits AnVps45, RabB coordinates PI(3)P-dependent endosome-to-vacuole traffic with incoming traffic from the Golgi and with long-distance endosomal motility. However, the finding that Anvps45Δ, unlike rabBΔ, severely impairs growth indicates that AnVps45 plays RabB-independent functions. Affinity chromatography showed that the CORVET complex is a RabB and, to a lesser extent, a RabA effector, in agreement with GST pulldown assays of AnVps8. rabBΔ leads to smaller vacuoles, suggesting that it impairs homotypic vacuolar fusion, which would agree with the sequential maturation of endosomal CORVET into HOPS proposed for Saccharomyces cerevisiae. rabBΔ and rabAΔ mutations are synthetically lethal, demonstrating that Rab5-mediated establishment of endosomal identity is essential for A. nidulans.

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Situmorang, Boldson Herdianto. „Identification of Biometrics Using Fingerprint Minutiae Extraction Based on Crossing Number Method“. Komputasi: Jurnal Ilmiah Ilmu Komputer dan Matematika 20, Nr. 1 (02.12.2022): 71–80. http://dx.doi.org/10.33751/komputasi.v20i1.6814.

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Biometrics based on fingerprint images is a self-recognition technique using fingerprint to represent a person's identity. Fingerprint is characteristic of someone's identity precisely and safely because there are no similarities and cannot be falsified. The purpose of this research is to develop a biometrics identification system based on fingerprint images by utilizing a cell phone camera for the acquisition of fingerprint images. This is based on its simplicity because almost everyone has a cell phone so that a person's identification system based on fingerprint can be used anytime and anywhere. The research was conducted using images generated from cell phone cameras with camera specifications of 2, 5 and 8 mega pixels. The method used in image processing consists of the minutiae crossing number method for the feature extraction process and the minutiae based matching method for the similarity measurement process. The results of the research concluded that cell phone cameras with specifications of 5 and 8 mega pixels can be used for the process of image acquisition in biometrics systems based on fingerprint. The feature extraction process of image results using the minutiae crossing number method and the match measurement process using the minutiae based matching method resulted in an accuracy value of 92.8% on a 5 mega pixel camera and 95.3% on an 8 mega pixel camera. The accuracy value depends on the results of the image acquisition stage, pre-processing, the threshold value in the identification process, and the number of images used in the training data in the database.

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Gomez, R. Ariel, Ellen Steward Pentz, Xuan Jin, Magali Cordaillat und Maria Luisa S. Sequeira Lopez. „CBP and p300 are essential for renin cell identity and morphological integrity of the kidney“. American Journal of Physiology-Heart and Circulatory Physiology 296, Nr. 5 (Mai 2009): H1255—H1262. http://dx.doi.org/10.1152/ajpheart.01266.2008.

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The mechanisms that govern the identity of renin cells are not well understood. We and others have identified cAMP as an important pathway in the regulation of renin synthesis and release. Recently, experiments in cells from the renin lineage led us to propose that acquisition and maintenance of renin cell identity are mediated by cAMP and histone acetylation at the cAMP responsive element (CRE) of the renin gene. Ultimately, the transcriptional effects of cAMP depend on binding of the appropriate transcription factors to CRE. It has been suggested that access of transcription factors to this region of the promoter is facilitated by the coactivators CREB-binding protein (CBP) and p300, which possess histone acetyltransferase activity and may be, in turn, responsible for the remodeling of chromatin underlying expression of the renin gene. We hypothesized that CBP and p300 are therefore required for expression of the renin gene and maintenance of the renin cell. Because mice homozygous for the deletion of CBP or p300 die before kidney organogenesis begins, no data on kidney or juxtaglomerular cell development in these mice are available. Therefore, to define the role of these histone acetyltransferases in renin cell identity in vivo, we used a conditional deletion approach, in which floxed CBP and p300 mice were crossed with mice expressing cre recombinase in renin cells. Results show that the histone acetyltransferases CBP and p300 are necessary for maintenance of renin cell identity and structural integrity of the kidney.

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Dissertationen zum Thema "Acquisition of cell identity"

Custo, Greig Luciano. „Progenitor Diversity, Lineage Commitment, and Acquisition of Cell-Type Identity in the Cerebral Cortex“. Thesis, Harvard University, 2017. http://nrs.harvard.edu/urn-3:HUL.InstRepos:32676122.

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An extraordinary variety of neuronal subtypes, each with distinct morphologies, patterns of connectivity, and electrophysiological properties, is generated during neocortical development. Elucidating programs of molecular controls that govern progressive specification of neuronal subtype identity in the cerebral cortex contributes toward our understanding its development, organization, evolution, and function. Establishing a basic framework for how and when cell fate specification decisions are made will enable more efficient manipulation of these transitions in vitro, and therefore has important practical implications for biomedical research, as it will help improve protocols for generation of specific cortical neuron subtypes for use in disease modeling, drug screening, and therapeutic transplantation.

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Fernandes, Gonçalo. „Imaging transcription in living embryos to decipher the robustness of patterning“. Electronic Thesis or Diss., Université Paris sciences et lettres, 2022. http://www.theses.fr/2022UPSLS025.

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Au cours du développement, les gradients morphogénétiques fournissent l’information positionnelle nécessaire à l’établissement des axes de polarité. Si l’importance de ces gradients est bien établie, la façon dont ils assurent la reproductibilité des patrons d’expression malgré la nature stochastique de la transcription reste énigmatique.Pour répondre à cette question, j’étudie l’établissement de l’axe antéro-postérieur (AP) de l’embryon de drosophile, sous contrôle de Bicoid (Bcd), un facteur de transcription et morphogène bien connu. Les ARNs de bcd sont exprimés maternellement et ancrés au pôle antérieur de l’ovocyte. Après la ponte, ces ARNs sont traduits en protéines, qui diffusent dans le cytoplasme pour former un gradient de concentration exponentiel avec son maximum au pôle antérieur. Un modèle simple propose que le destin de chaque cellule le long de l’axe est déterminé par la concentration de Bcd qu’elle reçoit. Toutefois, de nombreux débats ont remis en question la possibilité que les patrons d’expression induits par Bcd résultent uniquement des propriétés de diffusion et d’interaction des protéines Bcd avec leurs séquences cibles.L’objectif de ma thèse était de comprendre le rôle précis de Bcd dans l’expression de son gène cible principal, hunchback (hb). Pour cela, j’ai adapté à des gènes rapporteurs synthétiques, le système MS2-MCP, qui permet l’étiquetage fluorescent des ARN et l’analyse quantitative de la dynamique transcriptionnelle avec une forte résolution spatio-temporelle dans les embryons vivants. Dans ces rapporteurs, la séquence MS2 est contrôlée par un promoteur minimal contenant aussi les sites de fixation pour Bcd ou ses partenaires, Hb et Zelda (Zld), seul ou en combinaison. Mon but était de déterminer comment les divers rapporteurs récapitulent l’expression du promoteur d’hb et d’identifier les rôles spécifiques de chacun de ces facteurs et leurs interactions dans le mécanisme de transcription.De façon intéressante, l’expression du rapporteur avec uniquement neuf sites pour Bcd (trois de plus que dans le gène hb) récapitule l’expression du rapporteur hb-MS2, mais de façon moins rapide et avec un domaine d’expression à la bordure moins nette. Cela suggère qu’en définissant la position de la bordure mais pas sa netteté ni la rapidité de son établissement, Bcd est la source principale d’information positionnelle.En outre, la fixation des partenaires de Bcd au promoteur accélère le processus en agissant à différentes étapes : i) Hb agit en synergie avec Bcd en réduisant les fluctuations du promoteur et en augmentant le taux de démarrage de la polymérase ; ii) Zld abaisse le seuil de concentration de Bcd nécessaire à l’activation par Bcd. En collaboration avec des physiciens, nous avons développé un modèle de transcription impliquant Bcd et fournissant un contexte théorique aux données expérimentales. Ce modèle montre que l’établissement rapide de la bordure d’expression d’hb peut être expliqué par une réaction d’équilibre entre Bcd et ses sites de fixation pour l’information positionnelle nécessitant Zld et Hb pour sa dynamique temporelle.Pour confirmer que Bcd est la seule source d’information positionnelle du système, j’ai comparé la position de la bordure d’expression des gènes rapporteurs dépendant uniquement de Bcd dans des embryons exprimant une ou une demi-dose de Bcd. De manière surprenante, pour chaque rapporteur, le déplacement de la bordure est plus faible que son estimation théorique tenant compte de la constante du gradient exponentiel de concentration de Bcd. Cela indique une constante plus faible pour le gradient d’activité de Bcd et suggère l’existence de sous-populations de Bcd, avec certaines molécules moins actives que d’autres. L’amplitude du déplacement de la bordure du gène rapporteur hb-MS2 est la même que celle obtenue pour les rapporteurs dépendant uniquement de Bcd ce qui confirme que Bcd est bien la seule source d’information positionnelle pour l’expression d’hb
Morphogen gradients provide concentration-dependent positional information required to establish the polarity of developmental axes. Although the critical role of these gradients is well recognized, it is unclear how they provide reproducible expression patterns. This is particularly surprising if we consider the stochastic nature of transcription.To address this question, I focus on the establishment of the anterior-posterior (AP) axis of fruit fly embryos, which is mostly defined by Bicoid (Bcd), a very well-characterized morphogen and transcription factor. bcd mRNAs are expressed maternally and anchored at the anterior tip of the oocyte. After egg laying, these mRNAs are translated into proteins, which diffuse through the cytoplasm and form a gradient with its highest concentration at the anterior. A simple model is that depending on their position along the AP axis and thus on Bcd concentration, cells will adopt different fates. However, long debates in the field have questioned the possibility that Bcd-dependent transcription patterns emerge solely from diffusive biochemical interactions between limiting amounts of Bcd molecules and the gene promoter region.The goal of my PhD was to determine how Bcd precisely regulates expression of its main target gene, hunchback (hb). For this, I adapted to synthetic reporters the MS2-MCP system, which allows the fluorescent tagging of mRNAs and provides, thus, a quantitative analysis of transcription dynamics at high spatiotemporal resolution in living embryos. In these reporters, the MS2 sequence was placed under the control of a minimal promoter also containing DNA binding sites for Bcd and/or its known partners, Hb and Zelda (Zld), either alone or in combination. My goal was to determine how the various reporters could recapitulate expression of the hb promoter (hb-MS2 reporter) and shed light on the specific roles of the different factors and their interactions in the transcription mechanism.Interestingly, expression of the reporter with only nine Bcd binding sites (three more than in the hb gene) matches almost perfectly the hb-MS2 reporter pattern, except for the very high steepness of the expression domain boundary and the speed to reach steady-state. This suggests that Bcd alone is the main source of positional information, defining the positioning of the boundary but not its steepness nor the speed of its establishment.In addition, binding of Bcd’s partners to the promoter speed-up the process by acting in different steps of the transcription mechanism: i) Hb synergizes with Bcd by reducing transcription burstiness and increasing the polymerase firing rate; ii) Zld lowers the Bcd concentration threshold required for Bcd-dependent expression. In collaboration with physicists, a biophysical model of Bcd-dependent expression was developed providing a theoretical framework for the experimental data. This model showed that the very rapid establishment of the hb expression boundary can be solely explained by an equilibrium model involving the binding of Bcd molecules to their DNA-binding sites for positional information which requires Zld and Hb for its temporal dynamics.To further confirm that Bcd is the sole source of positional information for hb expression, I compared the boundary position of the Bcd-only dependent reporters in embryos expressing one dose or half dose of Bcd. Surprisingly, the corresponding shifts of these reporters’ boundaries upon one vs half dose of Bcd were smaller than theoretically expected given the measured decay length of the Bcd protein gradient. This indicates a shorter decay length for the Bcd activity gradient and suggests the existence of different Bcd populations, with some Bcd molecules being less active than others. Importantly, the shift observed for the hb-MS2 reporter was the same as for the Bcd-only dependent reporters confirming Bcd as the sole source of positional information for hb expression

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Jaeger, Baptiste. „Acquisition of natural killer cell effector capabilities“. Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4028.

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Les cellules Natural Killer (NK) sont des lymphocytes du système immunitaire inné capables de tuer des cellules cibles et de produire des cytokines telles que l'interféron-γ. Au cours de mon travail de thèse, j'ai utilisé des approches de génétique directe et inverse dans le but d'étudier les mécanismes impliqués dans la régulation des capacités effectrices des cellules NK. La tolérance des cellules NK au soi est en partie assurée par les récepteurs inhibiteurs de surface qui sont spécifiques des molécules du complexe majeur d'histocompatibilité de classe I (CMH-I) exprimées par les cellules du soi. Cependant, des cellules NK qui ne sont pas capables de détecter l'expression du CMH-I ne sont pas autoréactives. Dans la première partie de ce travail de thèse, nous avons cherché à déterminer, chez la souris, les mécanismes de la tolérance NK, indépendante de la reconnaissance du CMH-I, qui est associée à une hyporeactivité des cellules NK. En utilisant des techniques de spectrométrie de fluorescence par corrélation à spot variable (svFCS), nous avons montré que dans les cellules NK hyporéactives les récepteurs activateurs et inhibiteurs sont confinés à la membrane plasmique par des réseaux structurés d'actine. A l'inverse, la reconnaissance par les cellules NK du CMH-I, qui « éduque » les cellules NK pour qu'elles acquièrent leurs capacités effectrices maximales, est associée une relocalisation des récepteurs activateurs au sein de nanodomaines. Ces résultats suggèrent que ce serait le confinement particulier des récepteurs activateurs à la membrane des cellules NK qui assure la tolérance au soi
Natural killer (NK) cells are bone marrow-derived innate immune lymphocytes able to kill cellular targets and secrete cytokines such as interferon-γ. During my PhD work, I used reverse and forward genetic approaches to dissect the mechanisms involved in the regulation of NK cell effector capabilities at steady state. NK cell tolerance to self is partly ensured by major histocompatibility complex class I (MHC- I)-specific inhibitory receptors on NK cells, which detect MHC-I expression on self-cells and prevent NK cell activation. However, NK cells that do not detect self MHC-I are not autoreactive. In the first part of this PhD work, we sought to determine the mechanism at the basis of this MHC-I independent NK cell tolerance. Using spot variation fluorescence correlation spectroscopy (svFCS), we showed that MHC-I-independent NK cell tolerance in mice was associated with the presence of hyporesponsive NK cells in which both activating and inhibitory receptors were confined in an actin meshwork at the plasma membrane. In contrast, the recognition of self MHC-I by inhibitory receptors "educated" NK cells to become fully reactive, and activating NK cell receptors became dynamically compartmentalized in membrane nanodomains. We thus propose that the confinement of activating receptors at the plasma membrane is essential to ensuring self-tolerance of NK cells

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Lee, Ruey-Hua. „Cell-cell interactions during acquisition of embryogenic competence in yam (Dioscorea spp.)“. Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265044.

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Jörgensen, Eskil. „Cell Acquisition and Synchronization for Unlicensed NB-IoT“. Thesis, Linköpings universitet, Kommunikationssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-139862.

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Narrowband Internet-of-Things (NB-IoT) is a new wireless technology designed to support cellular networks with wide coverage for a massive number of very cheap low power user devices. Studies have been initiated for deployment of NB-IoT in unlicensed frequency bands, some of which demand the use of a frequency-hopping scheme with a short channel dwell time. In order for a device to connect to a cell, it must synchronize well within the dwell time in order to decode the frequency-hopping pattern. Due to the significant path loss, the narrow bandwidth and the device characteristics, decreasing the synchronization time is a challenge. This thesis studies different methods to decrease the synchronization time for NB-IoT without increasing the demands on the user device. The study shows how artificial fast fading can be combined with denser reference signalling in order to achieve improvements to the cell acquisition and synchronization procedure sufficient for enabling unlicensed operation of NB-IoT.
Narrowband Internet-of-Things (NB-IoT) är en ny trådlös teknik som är designad för att hantera mobilnät med vidsträckt täckning för ett massivt antal mycket billiga och strömsnåla användarenheter. Studier har inletts för att operera NB-IoT i olicensierade frekvensband, varav några kräver att frekvenshoppande spridningsspektrum, med kort uppehållstid per kanal, används. För att en användarenhet ska kunna ansluta till en basstation måste den slutföra synkronisingsfasen inom uppehållstiden, så att basstationens hoppmönster kan avkodas. På grund utav den stora signalförsvagningen, den smala bandbredden och användarenhetens egenskaper är det en stor utmaning att förkorta synkroniseringstiden. Detta examensarbete studerar olika metoder för att förkorta synkroniseringstiden i NB-IoT utan att öka kraven på användarenheten. Arbetet visar att artificiell snabb-fädning kan kombineras med tätare referenssignalering för att uppnå förbättringar i synkroniseringsprocessen som är tillräckliga för att möjliggöra operation av NB-IoT i olicensierade frekvensband.

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Knapp, David Jorg Hans Fraser. „Single-cell analysis of hematopoietic stem cell identity and behaviour“. Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55875.

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The concept of stem cell self-renewal was developed from clonal tracking of hematopoietic stem cell (HSC) divisions in vivo 50 years ago. However, protocols to expand these cells in vitro without loss of their stem cell properties have remained elusive. A number of factors contribute to this inability. Key among these is a lack of knowledge of the critical molecular characteristics that distinguish HSCs from hematopoietic progenitors as well as how the control of the fundamental biological programs of survival, division and differentiation are integrated in HSCs. Using a combination of single-cell tracking, transcriptomics, and in vivo readouts applied to highly enriched mouse HSCs, we now show that their survival, proliferation, and maintenance of stem cell properties are mechanistically dissociable. Discovery of a protocol that allows input numbers of functionally intact human HSC numbers to be maintained for 3 weeks in vitro using defined growth factors, was then leveraged to design single human HSC cell tracking and functional analyses. The results of these showed that for human HSC, as in the mouse model, survival, proliferation, and maintenance of stem cell status are mechanistically dissociable, and controlled in a combinatorial manner. We then developed a panel of mass cytometry detectors to enable >40 surface and intracellular proteins to be simultaneously measured at single cell resolution. Using this panel, we identified some of the signaling intermediates activated by growth factors that differentially control human HSC biological responses assessed in high-throughput assays. Correlation of the molecular properties, surface phenotypes and functional activities of CD34+ subsets have further revealed a surprising degree both of heterogeneity within each phenotype and overlap between phenotypes. In some cases, the results suggest a given phenotype contains distinct subsets and a broader scheme of differentiation pathways than suggested by current models of human hematopoietic cell differentiation. Finally, we identify CD33+ as a novel marker which demarcates the most potent human HSC within the current best phenotypic enrichment strategy. These results lay a foundation on which future HSC expansion strategies can be constructed, and have implications for the development of leukemia.
Medicine, Faculty of
Medicine, Department of
Experimental Medicine, Division of
Graduate

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Middleton, Michael W. „Assessing the value of the Joint Rapid Acquisition Cell“. Thesis, Monterey, Calif. : Naval Postgraduate School, 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FMiddleton.pdf.

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Mathur, Divya Ph D. Massachusetts Institute of Technology. „Molecular control of embryonic stem cell identity“. Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46786.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
Embryonic Stem (ES) cells are the in vitro derivatives of the inner cell mass of a developing embryo, and exhibit the property of pluripotency, which is the ability of a cell to give rise to all cell lineages of an organism. Therefore, these cells hold great promise in the treatment of several degenerative diseases through patientspecific cell-based therapy. Consequently, a detailed knowledge of the factors regulating ES cell identity is required in order to exploit this therapeutic potential. In order to address this subject, genome-wide location analysis (or ChIP-chip) has been used to identify downstream genes that are bound, and potentially regulated by the key pluripotency transcription factors, Oct4 and Nanog. The data from this study have also been compared and integrated with Oct4 and Nanog DNA binding data obtained in a different study using the ChIP-PET technology. In order to gain further insight into the mechanisms by which the transcription factor Nanog regulates its downstream targets, an attempt at identifying proteins interacting with Nanog has also been described. Research on ES cells has been plagued with ethical controversies since the creation of these cells requires the destruction of embryos. Recent studies have reported the reprogramming of somatic fibroblasts into an ES cell-like induced pluripotent state (iPS) by virus-mediated transduction of four transcription factors-- Oct4, Sox2, c-Myc and Klf4, thereby circumventing the use of embryos in producing pluripotent cells.In these studies, selection for the activation of the markers Oct4 or Nanog led to completely reprogrammed cells, but selection for fbx15, a downstream target of Oct4, resulted in partially reprogrammed intermediates. An unresolved issue in the field was whether these intermediates were obtained due to early drug selection in the case of fbx15 selection, or because Fbx15 expression is not relevant to pluripotency. Drug selection for fbx15 activation at later time-points, and an examination of the methylation status of the Oct4 locus of Fbx15-iPS cells suggests that the intermediates were obtained due to early drug selection and not due to selection for fbx15. Therefore, these studies have begun to elucidate a framework that governs ES cell identity, and the mechanism by which a differentiated cell can be reprogrammed into a pluripotent state.
by Divya Mathur.
Ph.D.

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Biltcliffe, Phillippa. „A cultural geography of Victorian art collecting : identity, acquisition and display“. Thesis, Royal Holloway, University of London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491729.

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Grounded within cultural geography, this thesis focuses on the relationships between art collection and the fashioning of elite identities in the second-half of the nineteenth century. Through two detailed case studies of wealthy collectors, it investigates the ways in which the consumption of art served as a cultural medium through which collectors created distinct identities for themselves, so that collections may be seen not simply as mirrors reflecting Victorian culture, but as constitutive of that culture. Focusing on the geographical aspects of the history of art collecting, the study considers how subjectivities were crafted through negotiation of a series of sites and spaces, collecting networks and journeys. This focus on the spatiality of collections and of collecting identities enriches existing notions of class, gentility and connoisseurship. The empirical core of the thesis is a study of the collections amassed by two wealthy Victorians: Ferdinand Rothschild (1839-1898), an aristocratic and cosmopolitan connoisseur, who specialised particularly in Renaissance and eighteenth-century art objects, and Thomas Holloway (1800-1883), a millionaire businessman and philanthropist known especially for his collection of contemporary Victorian paintings. Through a close examination of the activities and collections of these two very different figures, the thesis explores how their identities and reputations were fashioned through their collections. Part 1 of the thesis provides an account of recent work on the cultures of collecting and the fashioning of class identities, with particular reference to Victorian Britain (Chapter 2). Part 2 considers the relationships between collecting, taste and the fashioning of identities, with reference to Holloway and Rothschild (Chapters 3 and 4). Part 3 examines the different means through which objects were acquired; focusing especially on the contrasting sites of acquisition, including the auction house, the private sale, the art dealer and foreign travel (Chapter 5 and 6). Part 4 focuses on display, considering how art objects were made meaningful through their location in particular places, from the public gallery to the private smoking rooms.

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Donnelly, Stephen Kevin. „Ethnic identity redefinition during acquisition of one's ancestral language (Irish) : an approach based on identity structure analysis“. Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259582.

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Bücher zum Thema "Acquisition of cell identity"

H, Cantor, Glimcher Laurie und Alt Frederick W, Hrsg. T cell subsets: cellular selection, commitment and identity. Amsterdam: Elsevier Academic Press, 2004.

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Identity, agency and the acquisition of professional language and culture. London: Continuum, 2011.

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National Clearinghouse for ESL Literacy Education., Hrsg. Social identity and the adult ESL classroom. [Washington, DC]: U.S. Dept. of Education, Office of Educational Research and Improvement, Educational Resources Information Center, National Clearinghouse for ESL Literacy Education, 1997.

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Block, David. Second language identities. London: Continuum, 2009.

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Astuti, Rita. Constraints on conceptual development: A case study of the acquisition of folkbiological and folksociological knowledge in Madagascar. Boston, MA: Blackwell Pub., 2004.

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Astuti, Rita. Constraints on conceptual development: A case study of the acquisition of folkbiological and folksociological knowledge in Madagascar. Oxford: Blackwell, 2004.

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Astuti, Rita. Constraints on conceptual development: A case study of the acquisition of folkbiological and folksociological knowledge in Madagascar. Boston, MA: Blackwell Pub., 2004.

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Identity, motivation and autonomy in language learning. Bristol: Multilingual Matters, 2011.

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Donnelly, Stephen Kevin. Ethnic identity redefinition during acquisition of one's ancestral language (Irish): An approach based on identity structure analysis. [s.l: The Author], 1994.

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Haselton, H. T. A control and data acquisition system for use with a hydrothermal diamond-anvil cell. Reston, VA: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.

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Buchteile zum Thema "Acquisition of cell identity"

Darvin, Ron, und Bonny Norton. „Identity“. In The Routledge Handbook of Second Language Acquisition and Individual Differences, 235–50. New York: Routledge, 2022. http://dx.doi.org/10.4324/9781003270546-20.

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Vaish, Viniti. „Second Language Acquisition and Identity“. In Research Methods in Language and Education, 255–66. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-02249-9_19.

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Vaish, Viniti. „Second Language Acquisition and Identity“. In Research Methods in Language and Education, 1–12. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-02329-8_19-1.

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Joshi, Pranav, Kyeong-Nam Yu, Emily Serbinowski und Moo-Yeal Lee. „3D-Cultured Cell Image Acquisition“. In Microarray Bioprinting Technology, 125–42. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-46805-1_6.

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Matoh, Toru. „Boron in Plant Nutrition and Cell Wall Development“. In Plant Nutrient Acquisition, 227–50. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66902-9_10.

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Clapp, Mara, und Florence L. Marlow. „Acquisition of Oocyte Polarity“. In Results and Problems in Cell Differentiation, 71–102. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60855-6_4.

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Cornips, Leonie M. E. A., und Aafke Hulk. „Late language acquisition and identity construction“. In Studies in Language Variation, 57–68. Amsterdam: John Benjamins Publishing Company, 2013. http://dx.doi.org/10.1075/silv.14.04cor.

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Ae, Noriharu, Renfang Shen und Takashi Otani. „The Significance of the Root Cell Wall in Phosphorus Uptake“. In Plant Nutrient Acquisition, 251–75. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66902-9_11.

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Kato, Yoji. „Structure of Plant Cell Walls and Implications for Nutrient Acquisition“. In Plant Nutrient Acquisition, 276–96. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66902-9_12.

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Blamey, Frederick Pax C. „The Role of the Root Cell Wall in Aluminum Toxicity“. In Plant Nutrient Acquisition, 201–26. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66902-9_9.

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Konferenzberichte zum Thema "Acquisition of cell identity"

Annamdevula, Naga S., Santina Johnson, Donald J. Pleshinger, Shane Castleberry, William Russel, Andrea L. Britain, Michael M. Francis, Thomas C. Rich und Silas J. Leavesley. „Hyperspectral imaging and adaptive thresholding to identify agonist-induced cAMP signals in pulmonary microvascular endothelial cells“. In Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXIX, herausgegeben von Thomas G. Brown, Tony Wilson und Laura Waller. SPIE, 2022. http://dx.doi.org/10.1117/12.2608292.

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Terres, Hilario, Sandra Chavez, Raymundo Lopez, Arturo Lizardi, Araceli Lara und Juan R. Morales. „Study of the Lemon Drying Process Using a Solar Dryer“. In ASME 2015 9th International Conference on Energy Sustainability collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/es2015-49696.

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A complete study for a solar dryer is shown. In this work the lemon drying process is considered. Also, results for temperature distribution, currents lines velocities and density distribution are presented inside of the dryer chamber. Curves for dried are obtained when the lost mass of the lemon is measured. For this purpose, a digital balance is used and during several intervals of time the measures are done. A Compact Field point device of National Instrument is used to measure temperatures inside of the chamber in the dryer. Thermocouples k-type were placed in different points. By acquisition data, the values of temperature were measured for the test. By means of software (ANSYS) is discretized the inner zone and using the temperatures as boundary conditions. Solving the system defined for the equations according to the mesh defined, temperature, velocities and densities are determined. The results allowing to identify what is the behavior inside of the dryer and how the drying process happens. This way to study the drying process can be useful when the behavior inside of the chamber wants to be evaluated. In addition, this work can be useful in the design of solar dryers because allows to know how the trays can be placed to take advantage in the best way the solar energy in solar dryers.

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Mannapova, Katerina. „ADOLESCENCE AS A PERIOD OF ACQUISITION OF ADULT IDENTITY“. In Scientific Development of New Eastern Europe. Publishing House “Baltija Publishing”, 2019. http://dx.doi.org/10.30525/978-9934-588-13-6-11.

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Martynyuk, Valeriy, Mykola Fedula, Roman Petrus, Denis Makaryshkin und Liudmyla Kovtun. „Solar Cell Data Acquisition System“. In 2019 10th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS). IEEE, 2019. http://dx.doi.org/10.1109/idaacs.2019.8924386.

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Teyeb, Oumer, Gunnar Mildh und Anders Furusk̈r. „Physical Cell Identity Assignment in Heterogeneous Networks“. In 2012 IEEE Vehicular Technology Conference (VTC Fall). IEEE, 2012. http://dx.doi.org/10.1109/vtcfall.2012.6398941.

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Amirijoo, Mehdi, Pal Frenger, Fredrik Gunnarsson, Harald Kallin, Johan Moe und Kristina Zetterberg. „Neighbor cell relation list and measured cell identity management in LTE“. In NOMS 2008 - 2008 IEEE Network Operations and Management Symposium. IEEE, 2008. http://dx.doi.org/10.1109/noms.2008.4575129.

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Lee, Poongup, Jangkeun Jeong, Yo-han Kim und Jitae Shin. „Physical cell identity reservation for 3GPP LTE femtocell“. In the 4th International Conference. New York, New York, USA: ACM Press, 2010. http://dx.doi.org/10.1145/2108616.2108619.

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Daley, George Q. „Abstract SY04-03: Molecular networks defining cell identity“. In 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-sy04-03.

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Amirijoo, M., P. Frenger, F. Gunnarsson, H. Kallin, J. Moe und K. Zetterberg. „Neighbor Cell Relation List and Physical Cell Identity Self-Organization in LTE“. In ICC 2008 - 2008 IEEE International Conference on Communications Workshops. IEEE, 2008. http://dx.doi.org/10.1109/iccw.2008.12.

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Silva, Tomaz, Carla Morais und Luciano Moreira. „SECOND LANGUAGE ACQUISITION EDUCATORS’ PERCEPTIONS OF MOBILE DEVICES AND PROFESSIONAL IDENTITY“. In 14th International Technology, Education and Development Conference. IATED, 2020. http://dx.doi.org/10.21125/inted.2020.0759.

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Berichte der Organisationen zum Thema "Acquisition of cell identity"

Porat, Ron, Gregory T. McCollum, Amnon Lers und Charles L. Guy. Identification and characterization of genes involved in the acquisition of chilling tolerance in citrus fruit. United States Department of Agriculture, Dezember 2007. http://dx.doi.org/10.32747/2007.7587727.bard.

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Citrus, like many other tropical and subtropical fruit are sensitive to chilling temperatures. However, application of a pre-storage temperature conditioning (CD) treatment at 16°C for 7 d or of a hot water brushing (HWB) treatment at 60°C for 20 sec remarkably enhances chilling tolerance and reduces the development of chilling injuries (CI) upon storage at 5°C. In the current research, we proposed to identify and characterize grapefruit genes that are induced by CD, and may contribute to the acquisition of fruit chilling tolerance, by two different molecular approaches: cDNA array analysis and PCR cDNA subtraction. In addition, following the recent development and commercialization of the new Affymetrix Citrus Genome Array, we further performed genome-wide transcript profiling analysis following exposure to CD and chilling treatments. To conduct the cDNA array analysis, we constructed cDNA libraries from the peel tissue of CD- and HWB-treated grapefruit, and performed an EST sequencing project including sequencing of 3,456 cDNAs from each library. Based on the obtained sequence information, we chose 70 stress-responsive and chilling-related genes and spotted them on nylon membranes. Following hybridization the constructed cDNA arrays with RNA probes from control and CD-treated fruit and detailed confirmations by RT-PCR analysis, we found that six genes: lipid-transfer protein, metallothionein-like protein, catalase, GTP-binding protein, Lea5, and stress-responsive zinc finger protein, showed higher transcript levels in flavedo of conditioned than in non-conditioned fruit stored at 5 ᵒC. The transcript levels of another four genes: galactinol synthase, ACC oxidase, temperature-induced lipocalin, and chilling-inducible oxygenase, increased only in control untreated fruit but not in chilling-tolerant CD-treated fruit. By PCR cDNA subtraction analysis we identified 17 new chilling-responsive and HWB- and CD-induced genes. Overall, characterization of the expression patterns of these genes as well as of 11 more stress-related genes by RNA gel blot hybridizations revealed that the HWB treatment activated mainly the expression of stress-related genes(HSP19-I, HSP19-II, dehydrin, universal stress protein, EIN2, 1,3;4-β-D-glucanase, and SOD), whereas the CD treatment activated mainly the expression of lipid modification enzymes, including fatty acid disaturase2 (FAD2) and lipid transfer protein (LTP). Genome wide transcriptional profiling analysis using the newly developed Affymetrix Citrus GeneChip® microarray (including 30,171 citrus probe sets) revealed the identification of three different chilling-related regulons: 1,345 probe sets were significantly affected by chilling in both control and CD-treated fruits (chilling-response regulon), 509 probe sets were unique to the CD-treated fruits (chilling tolerance regulon), and 417 probe sets were unique to the chilling-sensitive control fruits (chilling stress regulon). Overall, exposure to chilling led to expression governed arrest of general cellular metabolic activity, including concretive down-regulation of cell wall, pathogen defense, photosynthesis, respiration, and protein, nucleic acid and secondary metabolism. On the other hand, chilling enhanced various adaptation processes, such as changes in the expression levels of transcripts related to membranes, lipid, sterol and carbohydrate metabolism, stress stimuli, hormone biosynthesis, and modifications in DNA binding and transcription factors.

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Kurtz, J. L., und J. Tulenko. Reliable Wireless Data Acquisition and Control Techniques within Nuclear Hot Cell Facilities. Office of Scientific and Technical Information (OSTI), September 2000. http://dx.doi.org/10.2172/777347.

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Splitter, Gary A., Menachem Banai und Jerome S. Harms. Brucella second messenger coordinates stages of infection. United States Department of Agriculture, Januar 2011. http://dx.doi.org/10.32747/2011.7699864.bard.

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Aim 1: To determine levels of this second messenger in: a) B. melitensiscyclic-dimericguanosinemonophosphate-regulating mutants (BMEI1448, BMEI1453, and BMEI1520), and b) B. melitensis16M (wild type) and mutant infections of macrophages and immune competent mice. (US lab primary) Aim 2: To determine proteomic differences between Brucelladeletion mutants BMEI1453 (high cyclic-dimericguanosinemonophosphate, chronic persistent state) and BMEI1520 (low cyclicdimericguanosinemonophosphate, acute virulent state) compared to wild type B. melitensisto identify the role of this second messenger in establishing the two polar states of brucellosis. (US lab primary with synergistic assistance from the Israel lab Aim 3: Determine the level of Brucellacyclic-dimericguanosinemonophosphate and transcriptional expression from naturally infected placenta. (Israel lab primary with synergistic assistance from the US lab). B. Background Brucellaspecies are Gram-negative, facultative intracellular bacterial pathogens that cause brucellosis, the most prevalent zoonosis worldwide. Brucellosis is characterized by increased abortion, weak offspring, and decreased milk production in animals. Humans are infected with Brucellaby consuming contaminated milk products or via inhalation of aerosolized bacteria from occupational hazards. Chronic human infections can result in complications such as liver damage, orchitis, endocarditis, and arthritis. Brucellaspp. have the ability to infect both professional and non-professional phagocytes. Because of this, Brucellaencounter varied environments both throughout the body and within a cell and must adapt accordingly. To date, few virulence factors have been identified in B. melitensisand even less is known about how these virulence factors are regulated. Subsequently, little is known about how Brucellaadapt to its rapidly changing environments, and how it alternates between acute and chronic virulence. Our studies suggest that decreased concentrations of cyclic dimericguanosinemonophosphate (c-di-GMP) lead to an acute virulent state and increased concentrations of c-di-GMP lead to persistent, chronic state of B. melitensisin a mouse model of infection. We hypothesize that B. melitensisuses c-di-GMP to transition from the chronic state of an infected host to the acute, virulent stage of infection in the placenta where the bacteria prepare to infect a new host. Studies on environmental pathogens such as Vibrio choleraeand Pseudomonas aeruginosasupport a mechanism where changes in c-di-GMP levels cause the bacterium to alternate between virulent and chronic states. Little work exists on understanding the role of c-di-GMP in dangerous intracellular pathogens, like Brucellathat is a frequent pathogen in Israeli domestic animals and U.S. elk and bison. Brucellamust carefully regulate virulence factors during infection of a host to ensure proper expression at appropriate times in response to host cues. Recently, the novel secondary signaling molecule c-di-GMP has been identified as a major component of bacterial regulation and we have identified c-di-GMP as an important signaling factor in B. melitensishost adaptation. C. Major conclusions, solutions, achievements 1. The B. melitensis1453 deletion mutant has increased c-di-GMP, while the 1520 deletion mutant has decreased c-di-GMP. 2. Both mutants grow similarly in in vitro cultures; however, the 1453 mutant has a microcolony phenotype both in vitro and in vivo 3. The 1453 mutant has increased crystal violet staining suggesting biofilm formation. 4. Scanning electron microscopy revealed an abnormal coccus appearance with in increased cell area. 5. Proteomic analysis revealed the 1453 mutant possessed increased production of proteins involved in cell wall processes, cell division, and the Type IV secretion system, and a decrease in proteins involved in amino acid transport/metabolism, carbohydrate metabolism, fatty acid production, and iron acquisition suggesting less preparedness for intracellular survival. 6. RNAseq analysis of bone marrow derived macrophages infected with the mutants revealed the host immune response is greatly reduced with the 1453 mutant infection. These findings support that microlocalization of proteins involved in c-di-GMP homeostasis serve a second messenger to B. melitensisregulating functions of the bacteria during infection of the host.

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Holcomb, Greg D. Design and Software Development of Automated Data Acquisition System for Load Cell Calibration. Fort Belvoir, VA: Defense Technical Information Center, Juli 1998. http://dx.doi.org/10.21236/ada370991.

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Greene, David L., und Dr K. G. Duleep. Bootstrapping a Sustainable North American PEM Fuel Cell Industry: Could a Federal Acquisition Program Make a Difference? Office of Scientific and Technical Information (OSTI), Oktober 2008. http://dx.doi.org/10.2172/969964.

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Aksay, Ilhan A., Nan Yao und Daniel M. Dabbs. Acquisition of the Gatan Image Filter System and an Environmental Cell for an Existing Phillips CM-200 FEG-TEM. Fort Belvoir, VA: Defense Technical Information Center, Februar 2001. http://dx.doi.org/10.21236/ada387368.

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Eshed-Williams, Leor, und Daniel Zilberman. Genetic and cellular networks regulating cell fate at the shoot apical meristem. United States Department of Agriculture, Januar 2014. http://dx.doi.org/10.32747/2014.7699862.bard.

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The shoot apical meristem establishes plant architecture by continuously producing new lateral organs such as leaves, axillary meristems and flowers throughout the plant life cycle. This unique capacity is achieved by a group of self-renewing pluripotent stem cells that give rise to founder cells, which can differentiate into multiple cell and tissue types in response to environmental and developmental cues. Cell fate specification at the shoot apical meristem is programmed primarily by transcription factors acting in a complex gene regulatory network. In this project we proposed to provide significant understanding of meristem maintenance and cell fate specification by studying four transcription factors acting at the meristem. Our original aim was to identify the direct target genes of WUS, STM, KNAT6 and CNA transcription factor in a genome wide scale and the manner by which they regulate their targets. Our goal was to integrate this data into a regulatory model of cell fate specification in the SAM and to identify key genes within the model for further study. We have generated transgenic plants carrying the four TF with two different tags and preformed chromatin Immunoprecipitation (ChIP) assay to identify the TF direct target genes. Due to unforeseen obstacles we have been delayed in achieving this aim but hope to accomplish it soon. Using the GR inducible system, genetic approach and transcriptome analysis [mRNA-seq] we provided a new look at meristem activity and its regulation of morphogenesis and phyllotaxy and propose a coherent framework for the role of many factors acting in meristem development and maintenance. We provided evidence for 3 different mechanisms for the regulation of WUS expression, DNA methylation, a second receptor pathway - the ERECTA receptor and the CNA TF that negatively regulates WUS expression in its own domain, the Organizing Center. We found that once the WUS expression level surpasses a certain threshold it alters cell identity at the periphery of the inflorescence meristem from floral meristem to carpel fate [FM]. When WUS expression highly elevated in the FM, the meristem turn into indeterminate. We showed that WUS activate cytokinine, inhibit auxin response and represses the genes required for root identity fate and that gradual increase in WUCHEL activity leads to gradual meristem enlargement that affect phyllotaxis. We also propose a model in which the direction of WUS domain expansion laterally or upward affects meristem structure differently. We preformed mRNA-seq on meristems with different size and structure followed by k-means clustering and identified groups of genes that are expressed in specific domains at the meristem. We will integrate this data with the ChIP-seq of the 4 TF to add another layer to the genetic network regulating meristem activity.

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Marchesi, Keenan, und Patrick W. (Patrick Wade) McLaughlin. Food-away-from-home acquisition trends throughout the COVID-19 pandemic. Washington, DC: USDA Economic Research Service, Mai 2023. http://dx.doi.org/10.32747/2023.8023697.ers.

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"The Coronavirus (COVID-19) pandemic and the ensuing policy responses disrupted how consumers in the United States acquired food away from home, and little is known about how they continued to access these goods. This report summarizes national-level trends in dollars U.S. consumers spent from December 2019-February 2020 through April-June 2022 at quick- and full-service restaurants by service mode (on-premise, drive-thru, delivery, and carry-out) and acquisition and ordering method. Results show that while on-premises (eating inside a restaurant) spending fell at quick- and full-service restaurants, spending at full-service restaurants remained much lower than pre-pandemic spending levels. USDA, Economic Research Service researchers found that consumers quickly adapted to other service modes, like delivery or drive-thru, and this offset many of the losses observed in spending at quick-service restaurants. The authors also observed that consumers increased spending via cell phone apps for carry-out and delivery orders at both types of restaurants relative to pre-pandemic spending. In short, while consumers' restaurant spending largely returned to pre-pandemic levels, many of the ways that consumers interacted with quick- and full-service restaurants immediately following the onset of the pandemic remained."

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Horwitz, Benjamin A., und Barbara Gillian Turgeon. Fungal Iron Acquisition, Oxidative Stress and Virulence in the Cochliobolus-maize Interaction. United States Department of Agriculture, März 2012. http://dx.doi.org/10.32747/2012.7709885.bard.

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Our project focused on genes for high affinity iron acquisition in Cochliobolus heterostrophus, a necrotrophic pathogen of maize, and their intertwined relationship to oxidative stress status and virulence of the fungus on the host. An intriguing question was why mutants lacking the nonribosomal peptide synthetase (NRPS) gene (NPS6) responsible for synthesis of the extracellular siderophore, coprogen, are sensitive to oxidative stress. Our overall objective was to understand the mechanistic connection between iron stress and oxidative stress as related to virulence of a plant pathogen to its host. The first objective was to examine the interface where small molecule peptide and reactive oxygen species (ROS) mechanisms overlap. The second objective was to determine if the molecular explanation for common function is common signal transduction pathways. These pathways, built around sensor kinases, response regulators, and transcription factors may link sequestering of iron, production of antioxidants, resistance to oxidative stress, and virulence. We tested these hypotheses by genetic manipulation of the pathogen, virulence assays on the host plant, and by following the expression of key fungal genes. An addition to the original program, made in the first year, was to develop, for fungi, a genetically encoded indicator of redox state based on the commercially available Gfp-based probe pHyper, designed for animal cell biology. We implemented several tools including a genetically encoded indicator of redox state, a procedure to grow iron-depleted plants, and constructed a number of new mutants in regulatory genes. Lack of the major Fe acquisition pathways results in an almost completely avirulent phenotype, showing how critical Fe acquisition is for the pathogen to cause disease. Mutants in conserved signaling pathways have normal ability to regulate NPS6 in response to Fe levels, as do mutants in Lae1 and Vel1, two master regulators of gene expression. Vel1 mutants are sensitive to oxidative stress, and the reason may be underexpression of a catalase gene. In nps6 mutants, CAT3 is also underexpressed, perhaps explaining the sensitivity to oxidative stress. We constructed a deletion mutant for the Fe sensor-regulator SreA and found that it is required for down regulation of NPS6 under Fe-replete conditions. Lack of SreA, though, did not make the fungus over-sensitive to ROS, though the mutant had a slow growth rate. This suggests that overproduction of siderophore under Fe-replete conditions is not very damaging. On the other hand, increasing Fe levels protected nps6 mutants from inhibition by ROS, implying that Fe-catalyzed Fenton reactions are not the main factor in its sensitivity to ROS. We have made some progress in understanding why siderophore mutants are sensitive to oxidative stress, and in doing so, defined some novel regulatory relationships. Catalase genes, which are not directly related to siderophore biosynthesis, are underexpressed in nps6 mutants, suggesting that the siderophore product (with or without bound Fe) may act as a signal. Siderophores, therefore, could be a target for intervention in the field, either by supplying an incorrect signal or blocking a signal normally provided during infection. We already know that nps6 mutants cause smaller lesions and have difficulty establishing invasive growth in the host. Lae1 and Vel1 are the first factors shown to regulate both super virulence conferred by T-toxin, and basic pathogenicity, due to unknown factors. The mutants are also altered in oxidative stress responses, key to success in the infection court, asexual and sexual development, essential for fungal dissemination in the field, aerial hyphal growth, and pigment biosynthesis, essential for survival in the field. Mutants in genes encoding NADPH oxidase (Nox) are compromised in development and virulence. Indeed the triple mutant, which should lack all Nox activity, was nearly avirulent. Again, gene expression experiments provided us with initial evidence that superoxide produced by the fungus may be most important as a signal. Blocking oxidant production by the pathogen may be a way to protect the plant host, in interactions with necrotrophs such as C. heterostrophus which seem to thrive in an oxidant environment.

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Yahav, Shlomo, John Brake und Orna Halevy. Pre-natal Epigenetic Adaptation to Improve Thermotolerance Acquisition and Performance of Fast-growing Meat-type Chickens. United States Department of Agriculture, September 2009. http://dx.doi.org/10.32747/2009.7592120.bard.

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: The necessity to improve broiler thermotolerance and performance led to the following hypothesis: (a) thethermoregulatory-response threshold for heat production can be altered by thermal manipulation (TM) during incubation so as to improve the acquisition of thermotolerance in the post-hatch broiler;and (b) TM during embryogenesis will improve myoblast proliferation during the embryonic and post-hatch periods with subsequent enhanced muscle growth and meat production. The original objectives of this study were as follow: 1. to assess the timing, temperature, duration, and turning frequency required for optimal TM during embryogenesis; 2. to evaluate the effect of TM during embryogenesis on thermoregulation (heat production and heat dissipation) during four phases: (1) embryogenesis, (2) at hatch, (3) during growth, and (4) during heat challenge near marketing age; 3. to investigate the stimulatory effect of thermotolerance on hormones that regulate thermogenesis and stress (T₄, T₃, corticosterone, glucagon); 4. to determine the effect of TM on performance (BW gain, feed intake, feed efficiency, carcass yield, breast muscle yield) of broiler chickens; and 5. to study the effect of TM during embryogenesis on skeletal muscle growth, including myoblast proliferation and fiber development, in the embryo and post-hatch chicks.This study has achieved all the original objectives. Only the plasma glucagon concentration (objective 3) was not measured as a result of technical obstacles. Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” In order to sustain or even improve broiler performance, TM during the period of embryogenesis when satellite cell population normally expand should increase absolute pectoralis muscle weight in broilers post-hatch. Major conclusions: Intermittent TM (39.5°C for 12 h/day) during embryogenesis when the thyroid and adrenal axis was developing and maturing (E7 to E16 inclusive) had a long lasting thermoregulatory effect that improved thermotolerance of broiler chickens exposed to acute thermal stress at market age by lowering their functional Tb set point, thus lowering metabolic rate at hatch, improving sensible heat loss, and significantly decreasing the level of stress. Increased machine ventilation rate was required during TM so as to supply the oxygen required for the periods of increased embryonic development. Enhancing embryonic development was found to be accomplished by a combination of pre-incubation heating of embryos for 12 h at 30°C, followed by increasing incubation temperature to 38°C during the first 3 days of incubation. It was further facilitated by increasing turning frequency of the eggs to 48 or 96 times daily. TM during critical phases of muscle development in the late-term chick embryo (E16 to E18) for 3 or 6 hours (39.5°C) had an immediate stimulatory effect on myoblast proliferation that lasted for up to two weeks post-hatch; this was followed by increased hypertrophy at later ages. The various incubation temperatures and TM durations focused on the fine-tuning of muscle development and growth processes during late-term embryogenesis as well as in post-hatch chickens.

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