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1
Stephens, Andrew D., Patrick Z. Liu, Edward J. Banigan, Luay M. Almassalha, Vadim Backman, Stephen A. Adam, Robert D. Goldman y John F. Marko. "Chromatin histone modifications and rigidity affect nuclear morphology independent of lamins". Molecular Biology of the Cell 29, n.º 2 (15 de enero de 2018): 220–33. http://dx.doi.org/10.1091/mbc.e17-06-0410.
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Chromatin decompaction via increasing euchromatin or decreasing heterochromatin results in a softer nucleus and abnormal nuclear blebbing, independent of lamin perturbations. Conversely, increasing heterochromatin stiffens the nucleus and rescues nuclear morphology in lamin-perturbed cells that present abnormal nuclear morphology.
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Domínguez, Fernando y Francisco J. Cejudo. "Identification of a nuclear-localized nuclease from wheat cells undergoing programmed cell death that is able to trigger DNA fragmentation and apoptotic morphology on nuclei from human cells". Biochemical Journal 397, n.º 3 (13 de julio de 2006): 529–36. http://dx.doi.org/10.1042/bj20051809.
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PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently or from a common ancestor in plants and animals. In the present study we describe a cell-free system, using wheat grain nucellar cells undergoing PCD, to analyse nucleus dismantling, the final stage of PCD. We have identified a Ca2+/Mg2+ nuclease and a serine protease localized to the nucleus of dying nucellar cells. Nuclear extracts from nucellar cells undergoing PCD triggered DNA fragmentation and other apoptotic morphology in nuclei from different plant tissues. Inhibition of the serine protease did not affect DNA laddering. Furthermore, we show that the nuclear extracts from plant cells triggered DNA fragmentation and apoptotic morphology in nuclei from human cells. The inhibition of the nucleolytic activity with Zn2+ or EDTA blocked the morphological changes of the nucleus. Moreover, nuclear extracts from apoptotic human cells triggered DNA fragmentation and apoptotic morphology in nuclei from plant cells. These results show that degradation of the nucleus is morphologically and biochemically similar in plant and animal cells. The implication of this finding on the origin of PCD in plants and animals is discussed.
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Croft, Jenny A., Joanna M. Bridger, Shelagh Boyle, Paul Perry, Peter Teague y Wendy A. Bickmore. "Differences in the Localization and Morphology of Chromosomes in the Human Nucleus". Journal of Cell Biology 145, n.º 6 (14 de junio de 1999): 1119–31. http://dx.doi.org/10.1083/jcb.145.6.1119.
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Using fluorescence in situ hybridization we show striking differences in nuclear position, chromosome morphology, and interactions with nuclear substructure for human chromosomes 18 and 19. Human chromosome 19 is shown to adopt a more internal position in the nucleus than chromosome 18 and to be more extensively associated with the nuclear matrix. The more peripheral localization of chromosome 18 is established early in the cell cycle and is maintained thereafter. We show that the preferential localization of chromosomes 18 and 19 in the nucleus is reflected in the orientation of translocation chromosomes in the nucleus. Lastly, we show that the inhibition of transcription can have gross, but reversible, effects on chromosome architecture. Our data demonstrate that the distribution of genomic sequences between chromosomes has implications for nuclear structure and we discuss our findings in relation to a model of the human nucleus that is functionally compartmentalized.
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Jacob, Justin T., Raji R. Nair, Brian G. Poll, Christopher M. Pineda, Ryan P. Hobbs, Michael J. Matunis y Pierre A. Coulombe. "Keratin 17 regulates nuclear morphology and chromatin organization". Journal of Cell Science 133, n.º 20 (2 de octubre de 2020): jcs254094. http://dx.doi.org/10.1242/jcs.254094.
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ABSTRACTKeratin 17 (KRT17; K17), a non-lamin intermediate filament protein, was recently found to occur in the nucleus. We report here on K17-dependent differences in nuclear morphology, chromatin organization, and cell proliferation. Human tumor keratinocyte cell lines lacking K17 exhibit flatter nuclei relative to normal. Re-expression of wild-type K17, but not a mutant form lacking an intact nuclear localization signal (NLS), rescues nuclear morphology in KRT17-null cells. Analyses of primary cultures of skin keratinocytes from a mouse strain expressing K17 with a mutated NLS corroborated these findings. Proteomics screens identified K17-interacting nuclear proteins with known roles in gene expression, chromatin organization and RNA processing. Key histone modifications and LAP2β (an isoform encoded by TMPO) localization within the nucleus are altered in the absence of K17, correlating with decreased cell proliferation and suppression of GLI1 target genes. Nuclear K17 thus impacts nuclear morphology with an associated impact on chromatin organization, gene expression, and proliferation in epithelial cells.This article has an associated First Person interview with the first author of the paper.
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Fang, Chao, Jiaxing Yao, Xingyu Xia y Yuan Lin. "Modelling Nuclear Morphology and Shape Transformation: A Review". Membranes 11, n.º 7 (16 de julio de 2021): 540. http://dx.doi.org/10.3390/membranes11070540.
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As one of the most important cellular compartments, the nucleus contains genetic materials and separates them from the cytoplasm with the nuclear envelope (NE), a thin membrane that is susceptible to deformations caused by intracellular forces. Interestingly, accumulating evidence has also indicated that the morphology change of NE is tightly related to nuclear mechanotransduction and the pathogenesis of diseases such as cancer and Hutchinson–Gilford Progeria Syndrome. Theoretically, with the help of well-designed experiments, significant progress has been made in understanding the physical mechanisms behind nuclear shape transformation in different cellular processes as well as its biological implications. Here, we review different continuum-level (i.e., energy minimization, boundary integral and finite element-based) approaches that have been developed to predict the morphology and shape change of the cell nucleus. Essential gradients, relative advantages and limitations of each model will be discussed in detail, with the hope of sparking a greater research interest in this important topic in the future.
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Manda, Naresh Kumar, Upendarrao Golla, Kishore Sesham, Parth Desai, Shrushti Joshi, Satyam Patel, Sharada Nalla et al. "Tuning between Nuclear Organization and Functionality in Health and Disease". Cells 12, n.º 5 (23 de febrero de 2023): 706. http://dx.doi.org/10.3390/cells12050706.
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The organization of eukaryotic genome in the nucleus, a double-membraned organelle separated from the cytoplasm, is highly complex and dynamic. The functional architecture of the nucleus is confined by the layers of internal and cytoplasmic elements, including chromatin organization, nuclear envelope associated proteome and transport, nuclear–cytoskeletal contacts, and the mechano-regulatory signaling cascades. The size and morphology of the nucleus could impose a significant impact on nuclear mechanics, chromatin organization, gene expression, cell functionality and disease development. The maintenance of nuclear organization during genetic or physical perturbation is crucial for the viability and lifespan of the cell. Abnormal nuclear envelope morphologies, such as invagination and blebbing, have functional implications in several human disorders, including cancer, accelerated aging, thyroid disorders, and different types of neuro-muscular diseases. Despite the evident interplay between nuclear structure and nuclear function, our knowledge about the underlying molecular mechanisms for regulation of nuclear morphology and cell functionality during health and illness is rather poor. This review highlights the essential nuclear, cellular, and extracellular components that govern the organization of nuclei and functional consequences associated with nuclear morphometric aberrations. Finally, we discuss the recent developments with diagnostic and therapeutic implications targeting nuclear morphology in health and disease.
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Brown, Keith W., Thomas White, J. M. Wardlaw, Nicholas Walker y D. Foley. "Caudate Nucleus Morphology in Tardive Dyskinesia". British Journal of Psychiatry 169, n.º 5 (noviembre de 1996): 631–36. http://dx.doi.org/10.1192/bjp.169.5.631.
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ObjectiveThe objective of this project was to test whether there are differences in the size of the caudate nucleus in schizophrenic in-patients with and without tardive dyskinesia.MethodThe study was cross-sectional in design, examining group differences between institutionalised schizophrenic patients with and without tardive dyskinesia, using non-enhanced computerised tomography scans of the brain. The group comprised 15 schizophrenic patients with persistent tardive dyskinesia and 21 in-patient schizophrenic controls who were group-matched for demographic variables.ResultsThe dyskinetic subjects had a significantly larger left caudate nucleus and tended to have a larger right caudate nucleus than the controls. There were no differences between the groups on any of the measures of cerebral atrophy.ConclusionsThe findings can be understood within the context of models of neostriatal function. It is possible that a larger caudate nucleus could be used to identify patients at risk of developing tardive dyskinesia.
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Ibata, Yasuhiko, Hitoshi Okamura, Masaki Tanaka, Yoshitaka Tamada, Seiji Hayashi, Norio Iijima, Tomoyuki Matsuda et al. "Functional Morphology of the Suprachiasmatic Nucleus". Frontiers in Neuroendocrinology 20, n.º 3 (julio de 1999): 241–68. http://dx.doi.org/10.1006/frne.1999.0180.
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Santana-Sosa, Silvia, Emiliano Matos-Perdomo, Jessel Ayra-Plasencia y Félix Machín. "A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace". International Journal of Molecular Sciences 24, n.º 12 (6 de junio de 2023): 9829. http://dx.doi.org/10.3390/ijms24129829.
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The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
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Grandis, Annamaria, Cristiano Bombardi, Beatrice Travostini, Arcangelo Gentile, Monica Joechler, Luciano Pisoni y Roberto Chiocchetti. "Vestibular nuclear complex in cattle: Topography, morphology, cytoarchitecture and lumbo-sacral projections". Journal of Vestibular Research 17, n.º 1 (1 de septiembre de 2007): 9–24. http://dx.doi.org/10.3233/ves-2007-17102.
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The topography and the main characteristics of the vestibular nuclear complex (VNC) in cattle have been studied in serially transversally cut Nissl and Gles-stained sections. By using computerized image analysis software, the cell size, the maximum and minimum diameter of the neurons of each vestibular nucleus were obtained. These parameters were statistically analyzed by comparing the cell population from different nuclei and different parts of each nucleus. Furthermore, in order to investigate the lumbo-sacral projections, the fluorescent tracer Fast Blue was injected into the L6-S1 spinal cord of three calves. Among the vestibular nuclei, the superior was the least extensive rostro-caudally, the medial was the most extensive and contained the smallest cells, the lateral showed the largest neurons, and the descending nucleus contained cells of intermediate size which decreased in a rostrocaudal direction. Concerning the lumbo-sacral projections of the bovine VNC, the present study showed that only the fibers coming from the lateral vestibular nucleus reached the L6-S1 spinal cord. The labelled neurons were most heavily concentrated in the dorsal portion of this nucleus, but scattered neurons were also observed throughout the entire extension of the nucleus. The differences between the descriptions of cattle and other species were described.
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MARTIN, JOHN, NAOKI KOGO, TIAN XING FAN y MICHAEL ARIEL. "Morphology of the turtle accessory optic system". Visual Neuroscience 20, n.º 6 (noviembre de 2003): 639–49. http://dx.doi.org/10.1017/s0952523803206064.
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Neural signals of the moving visual world are detected by a subclass of retinal ganglion cells that project to the accessory optic system in the vertebrate brainstem. We studied the dendritic morphologies and direction tuning of these brainstem neurons in turtle (Pseudemys scripta elegans) to understand their role in visual processing. Full-field checkerboard patterns were drifted on the contralateral retina while whole-cell recordings were made in the basal optic nucleus in an intact brainstem preparation in vitro. Neurobiotin diffused into the neurons during the recording and was subsequently localized in brain sections. Neuronal morphologies were traced using appropriate computer software to analyze their position in the brainstem. Most labeled neurons were fusiform in shape and had numerous varicosities along their processes. The majority of dendritic trees spread out in a transverse plane perpendicular to the rostrocaudal axis of the nucleus. Neurons near the brainstem surface were often oriented tangential to that surface, whereas more cells at the dorsal side of the nucleus were oriented radial to the brainstem surface. Further analysis of Nissl-stained neurons revealed the largest neurons are located in the rostral and medial portions of the nucleus although neurons are most densely packed in the middle of the nucleus. The preferred directions of the visual responses of the neurons in this sample did not correlate with their morphology and position in the nucleus. Therefore, the morphology of the cells in the turtle accessory optic system appears dependent on its position within the nucleus while its visual responses may depend on the synaptic inputs that contact each cell.
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Stephens, Andrew D., Patrick Z. Liu, Viswajit Kandula, Haimei Chen, Luay M. Almassalha, Cameron Herman, Vadim Backman et al. "Physicochemical mechanotransduction alters nuclear shape and mechanics via heterochromatin formation". Molecular Biology of the Cell 30, n.º 17 (agosto de 2019): 2320–30. http://dx.doi.org/10.1091/mbc.e19-05-0286.
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The nucleus houses, organizes, and protects chromatin to ensure genome integrity and proper gene expression, but how the nucleus adapts mechanically to changes in the extracellular environment is poorly understood. Recent studies have revealed that extracellular physical stresses induce chromatin compaction via mechanotransductive processes. We report that increased extracellular multivalent cations lead to increased heterochromatin levels through activation of mechanosensitive ion channels (MSCs), without large-scale cell stretching. In cells with perturbed chromatin or lamins, this increase in heterochromatin suppresses nuclear blebbing associated with nuclear rupture and DNA damage. Through micromanipulation force measurements, we show that this increase in heterochromatin increases chromatin-based nuclear rigidity, which protects nuclear morphology and function. In addition, transduction of elevated extracellular cations rescues nuclear morphology in model and patient cells of human diseases, including progeria and the breast cancer model cell line MDA-MB-231. We conclude that nuclear mechanics, morphology, and function can be modulated by cell sensing of the extracellular environment through MSCs and consequent changes to histone modification state and chromatin-based nuclear rigidity.
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Adams, J. C. "Neuronal Morphology in the Human Cochlear Nucleus". Archives of Otolaryngology - Head and Neck Surgery 112, n.º 12 (1 de diciembre de 1986): 1253–61. http://dx.doi.org/10.1001/archotol.1986.03780120017003.
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Morgan, Joshua T., Emily R. Pfeiffer, Twanda L. Thirkill, Priyadarsini Kumar, Gordon Peng, Heidi N. Fridolfsson, Gordon C. Douglas, Daniel A. Starr y Abdul I. Barakat. "Nesprin-3 regulates endothelial cell morphology, perinuclear cytoskeletal architecture, and flow-induced polarization". Molecular Biology of the Cell 22, n.º 22 (15 de noviembre de 2011): 4324–34. http://dx.doi.org/10.1091/mbc.e11-04-0287.
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Changes in blood flow regulate gene expression and protein synthesis in vascular endothelial cells, and this regulation is involved in the development of atherosclerosis. How mechanical stimuli are transmitted from the endothelial luminal surface to the nucleus is incompletely understood. The linker of nucleus and cytoskeleton (LINC) complexes have been proposed as part of a continuous physical link between the plasma membrane and subnuclear structures. LINC proteins nesprin-1, -2, and -4 have been shown to mediate nuclear positioning via microtubule motors and actin. Although nesprin-3 connects intermediate filaments to the nucleus, no functional consequences of nesprin-3 mutations on cellular processes have been described. Here we show that nesprin-3 is robustly expressed in human aortic endothelial cells (HAECs) and localizes to the nuclear envelope. Nesprin-3 regulates HAEC morphology, with nesprin-3 knockdown inducing prominent cellular elongation. Nesprin-3 also organizes perinuclear cytoskeletal organization and is required to attach the centrosome to the nuclear envelope. Finally, nesprin-3 is required for flow-induced polarization of the centrosome and flow-induced migration in HAECs. These results represent the most complete description to date of nesprin-3 function and suggest that nesprin-3 regulates vascular endothelial cell shape, perinuclear cytoskeletal architecture, and important aspects of flow-mediated mechanotransduction.
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Areshidze, David A. "MECHANISMS OF THE KEEPING AND CHANGE OF FORMS AND SIZES OF THE CELL NUCLEI (REVIEW)". Morphological newsletter 30, n.º 3 (13 de agosto de 2022): 73–80. http://dx.doi.org/10.20340/mv-mn.2022.30(3).670.
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The size and shape of the cell nucleus are the frequently used parameters in the studies of Russian and foreign-states authors, not only as necessary for calculating the nuclear-cytoplasmic ratio of a cell in ontogenesis, differentiation, and pathological processes, but also having values as such. However, in discussions, two extreme points of view are expressed on the value of information about the shape and, especially, about the size of the nucleus. According to the first point of view, the morphometry of the size and shape of the cell nucleus without measuring the cytoplasm with the subsequent calculation of the nuclear-cytoplasmic ratio does not make any sense, and the data obtained do not carry significant information. Proponents of the second point of view consider the cell nucleus as a labile and significant indicator of the morphological and functional state of the cell, the size and shape of which change during normal aging, pathological conditions, proliferation, gene expression, and protein synthesis. In this regard, a meta-analysis of modern scientific literature devoted to the study of the mechanisms of maintaining and changing the size and shape of the cell nucleus was carried out. The data obtained were subjected to an analytical study in order to formulate and explain the structures, factors and mechanisms of maintenance, changes in the size, shape of the cell nucleus. Based on the analysis of data from Russian and foreign-states sources, it can be confidently stated that the amount of DNA in the nucleus is not the only factor that determines its size and shape, but also the structure and modification of chromatin can affect nuclear morphology. It can be considered proven that the leading structures of the cell that determine the size and shape of the cell nucleus are the cytoskeleton, the complex of nuclear pores, the nuclear lamina, the endoplasmic reticulum, and the factors are nuclear-cytoplasmic exchange and osmolarity. Further study of the structures and factors affecting the size and shape of the nucleus, establishing the relationship between its morphology and processes occurring at the tissue and cellular levels, promises to provide new approaches to the diagnosis, prevention and treatment of a number of diseases.
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Liu, Lingling, Qing Luo, Jinghui Sun y Guanbin Song. "Cytoskeletal control of nuclear morphology and stiffness are required for OPN-induced bone-marrow-derived mesenchymal stem cell migration". Biochemistry and Cell Biology 97, n.º 4 (agosto de 2019): 463–70. http://dx.doi.org/10.1139/bcb-2018-0263.
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During cell migration, the movement of the nucleus must be coordinated with the cytoskeletal dynamics that influence the efficiency of cell migration. Our previous study demonstrated that osteopontin (OPN) significantly promotes the migration of bone-marrow-derived mesenchymal stem cells (BMSCs). However, the mechanism that regulates nuclear mechanics of the cytoskeleton during OPN-promoted BMSC migration remains unclear. In this study, we investigated how the actin cytoskeleton influences nuclear mechanics in BMSCs. We assessed the morphology and mechanics of the nuclei in the OPN-treated BMSCs subjected to disruption or polymerization of the actin cytoskeleton. We found that disruption of actin organization by cytochalasin D (Cyto D) resulted in a decrease in the nuclear projected area and nuclear stiffness. Stabilizing the actin assembly with jasplakinolide (JASP) resulted in an increase in the nuclear projected area and nuclear stiffness. SUN1 (Sad-1/UNC-84 1) is a component of the LINC (linker of nucleoskeleton and cytoskeleton) complex involved in the connections between the nucleus and the cytoskeleton. We found that SUN1 depletion by RNAi decreased the nuclear stiffness and OPN-promoted BMSC migration. Thus, the F-actin cytoskeleton plays an important role in determining the morphology and mechanical properties of the nucleus. We suggest that the cytoskeletal–nuclear interconnectivity through SUN1 proteins plays an important role in OPN-promoted BMSC migration.
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Szollosi, D., R. Czolowska, M. S. Szollosi y A. K. Tarkowski. "Remodeling of mouse thymocyte nuclei depends on the time of their transfer into activated, homologous oocytes". Journal of Cell Science 91, n.º 4 (1 de diciembre de 1988): 603–13. http://dx.doi.org/10.1242/jcs.91.4.603.
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The potential of parthenogenetically activated mouse oocytes to remodel somatic cell nuclei was studied by ultrastructural means using oocyte-thymocyte hybrids. Complete nuclear remodeling, initiated by nuclear envelope breakdown and chromosome condensation (which is followed by formation of pronucleus-like nucleus) is possible only during a short time gap between metaphase II and telophase of meiotic division. Maturation-promoting factor activity is high during this period. The thymocyte nucleus can follow the sequence of morphological changes only in concert with the development of the native nucleus and only after exposure of the chromatin to the ooplasm. If hybridization is effected with pronucleate oocytes, the thymocyte nucleus retains its interphase character but shows particular modifications in nucleolar morphology (identical to changes observed during reactivation of the nucleolus in stimulated lymphocyte) and in the activity of the nuclear envelope (blebbing). Thus the nucleus not exposed to maturation-promoting factor activity may be influenced by a ‘programme’ specific for oocyte (blebbing) and by a programme inherent in the introduced somatic cell nucleus.
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Sengupta, Duhita, Sk Nishan Ali, Aditya Bhattacharya, Joy Mustafi, Asima Mukhopadhyay y Kaushik Sengupta. "A deep hybrid learning pipeline for accurate diagnosis of ovarian cancer based on nuclear morphology". PLOS ONE 17, n.º 1 (7 de enero de 2022): e0261181. http://dx.doi.org/10.1371/journal.pone.0261181.
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Nuclear morphological features are potent determining factors for clinical diagnostic approaches adopted by pathologists to analyze the malignant potential of cancer cells. Considering the structural alteration of the nucleus in cancer cells, various groups have developed machine learning techniques based on variation in nuclear morphometric information like nuclear shape, size, nucleus-cytoplasm ratio and various non-parametric methods like deep learning have also been tested for analyzing immunohistochemistry images of tissue samples for diagnosing various cancers. We aim to correlate the morphometric features of the nucleus along with the distribution of nuclear lamin proteins with classical machine learning to differentiate between normal and ovarian cancer tissues. It has already been elucidated that in ovarian cancer, the extent of alteration in nuclear shape and morphology can modulate genetic changes and thus can be utilized to predict the outcome of low to a high form of serous carcinoma. In this work, we have performed exhaustive imaging of ovarian cancer versus normal tissue and developed a dual pipeline architecture that combines the matrices of morphometric parameters with deep learning techniques of auto feature extraction from pre-processed images. This novel Deep Hybrid Learning model, though derived from classical machine learning algorithms and standard CNN, showed a training and validation AUC score of 0.99 whereas the test AUC score turned out to be 1.00. The improved feature engineering enabled us to differentiate between cancerous and non-cancerous samples successfully from this pilot study.
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Stepanchuk, A. P. "MORPHOLOGY AND FUNCTION OF THE AUTONOMOUS NERVOUS SYSTEM". Актуальні проблеми сучасної медицини: Вісник Української медичної стоматологічної академії 20, n.º 1 (11 de abril de 2020): 212–17. http://dx.doi.org/10.31718/2077-1096.20.1.212.
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The autonomic nervous system consists of the sympathetic and parasympathetic divisions. The central part is represented by supra-segmental and segmental centres. Parasympathetic segmental centres in the brain are accessory nucleus of the oculomotor nerves, superior salivary nucleus of the facial nerve, inferior salivary nucleus of the glossopharyngeal nerve and dorsal nucleus of the vagus nerve. In the spinal cord, these are the intermediate lateral nuclei. Sympathetic segmental centres in the brain are absent, and in the spinal cord, intermediate-lateral nuclei are located in the lateral horns in the eighth cervical, all thoracic and 1-2 lumbar spinal segments. The peripheral part of the autonomic nervous system is represented by pre-nodal and post-nodal branches, paravertebral, prevertebral and terminal nodes and plexuses. The intramural part of the autonomic nervous system lies in the larger part of a wide and narrow-loop net and represented with a large number of nerve cells different by their shapes and sizes and clustered as intramural nodes, or individual nerve cells included along the net loops. The autonomic plexuses of the abdominal cavity are topographically divided into celiac, superior and inferior mesenteric, abdominal aortic, mesenteric, superior and inferior hypogastric region.
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Meier, David S. "The nucleus of IC 342 as a potential twin of the Galactic center". Proceedings of the International Astronomical Union 9, S303 (octubre de 2013): 66–68. http://dx.doi.org/10.1017/s1743921314000167.
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AbstractThe Galactic center (GC), being the closest nucleus, holds a position of privilege in the study of galaxy centers, but because it is edge-on and hidden behind 30 magnitudes of visual extinction it is often difficult to understand the overall structure of the region. Nearby galactic nuclei potentially provide a guide to understanding the large-scale structure of the GC. High resolution maps of molecular line emission along with radio and optical continuum towards the nucleus of the nearby, face-on spiral IC 342 are discussed. Attention is focused on a comparison of the large-scale morphology, gas chemistry, and star formation between the two nuclei. The case is made that IC 342 is one of the best extragalactic templates for the GC. Both have a star formation rate within a factor of two of each other and an ISM morphology characterized by a R 300 pc central molecular zone formed from a pair of arms laced with a collection of dense star forming molecular clouds. IC 342 also exhibits a nuclear cluster and associated circumnuclear disk. Whether the nuclear morphology and chemistry in IC 342 is an extension of the disk bar, a separate nuclear bar, or results from radiative/mechanical feedback remains unsettled.
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Tamura, Kentaro y Ikuko Hara-Nishimura. "Involvement of the nuclear pore complex in morphology of the plant nucleus". Nucleus 2, n.º 3 (mayo de 2011): 168–72. http://dx.doi.org/10.4161/nucl.2.3.16175.
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Castellanos, F. X., J. N. Giedd, P. Eckburg, W. L. Marsh, P. Kozuch, A. C. King, S. D. Hamburger, G. F. Rithcie y J. L. Rapoport. "Quantitative morphology of the caudate nucleus in ADHD". Biological Psychiatry 35, n.º 9 (mayo de 1994): 725. http://dx.doi.org/10.1016/0006-3223(94)91052-9.
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Lauer, Tod R. "The morphology of multiple-nucleus brightest cluster galaxies". Astrophysical Journal 325 (febrero de 1988): 49. http://dx.doi.org/10.1086/165982.
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dos Santos, Ália y Christopher P. Toseland. "Regulation of Nuclear Mechanics and the Impact on DNA Damage". International Journal of Molecular Sciences 22, n.º 6 (20 de marzo de 2021): 3178. http://dx.doi.org/10.3390/ijms22063178.
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In eukaryotic cells, the nucleus houses the genomic material of the cell. The physical properties of the nucleus and its ability to sense external mechanical cues are tightly linked to the regulation of cellular events, such as gene expression. Nuclear mechanics and morphology are altered in many diseases such as cancer and premature ageing syndromes. Therefore, it is important to understand how different components contribute to nuclear processes, organisation and mechanics, and how they are misregulated in disease. Although, over the years, studies have focused on the nuclear lamina—a mesh of intermediate filament proteins residing between the chromatin and the nuclear membrane—there is growing evidence that chromatin structure and factors that regulate chromatin organisation are essential contributors to the physical properties of the nucleus. Here, we review the main structural components that contribute to the mechanical properties of the nucleus, with particular emphasis on chromatin structure. We also provide an example of how nuclear stiffness can both impact and be affected by cellular processes such as DNA damage and repair.
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Alisafaei, Farid, Doorgesh Sharma Jokhun, G. V. Shivashankar y Vivek B. Shenoy. "Regulation of nuclear architecture, mechanics, and nucleocytoplasmic shuttling of epigenetic factors by cell geometric constraints". Proceedings of the National Academy of Sciences 116, n.º 27 (17 de junio de 2019): 13200–13209. http://dx.doi.org/10.1073/pnas.1902035116.
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Cells sense mechanical signals from their microenvironment and transduce them to the nucleus to regulate gene expression programs. To elucidate the physical mechanisms involved in this regulation, we developed an active 3D chemomechanical model to describe the three-way feedback between the adhesions, the cytoskeleton, and the nucleus. The model shows local tensile stresses generated at the interface of the cell and the extracellular matrix regulate the properties of the nucleus, including nuclear morphology, levels of lamin A,C, and histone deacetylation, as these tensile stresses 1) are transmitted to the nucleus through cytoskeletal physical links and 2) trigger an actomyosin-dependent shuttling of epigenetic factors. We then show how cell geometric constraints affect the local tensile stresses and subsequently the three-way feedback and induce cytoskeleton-mediated alterations in the properties of the nucleus such as nuclear lamina softening, chromatin stiffening, nuclear lamina invaginations, increase in nuclear height, and shrinkage of nuclear volume. We predict a phase diagram that describes how the disruption of cytoskeletal components impacts the feedback and subsequently induce contractility-dependent alterations in the properties of the nucleus. Our simulations show that these changes in contractility levels can be also used as predictors of nucleocytoplasmic shuttling of transcription factors and the level of chromatin condensation. The predictions are experimentally validated by studying the properties of nuclei of fibroblasts on micropatterned substrates with different shapes and areas.
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Jin, Jianfeng, Richard T. Jaspers, Gang Wu, Joannes A. M. Korfage, Jenneke Klein-Nulend y Astrid D. Bakker. "Shear Stress Modulates Osteoblast Cell and Nucleus Morphology and Volume". International Journal of Molecular Sciences 21, n.º 21 (7 de noviembre de 2020): 8361. http://dx.doi.org/10.3390/ijms21218361.
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Mechanical loading preserves bone mass and function—yet, little is known about the cell biological basis behind this preservation. For example, cell and nucleus morphology are critically important for cell function, but how these morphological characteristics are affected by the physiological mechanical loading of bone cells is under-investigated. This study aims to determine the effects of fluid shear stress on cell and nucleus morphology and volume of osteoblasts, and how these effects relate to changes in actin cytoskeleton and focal adhesion formation. Mouse calvaria 3T3-E1 (MC3T3-E1) osteoblasts were treated with or without 1 h pulsating fluid flow (PFF). Live-cell imaging was performed every 10 min during PFF and immediately after PFF. Cytoskeletal organization and focal adhesions were visualized, and gene and protein expression quantified. Two-dimensional (2D) and three-dimensional (3D) morphometric analyses were made using MeasureStack and medical imaging interaction toolkit (MITK) software. 2D-images revealed that 1 h PFF changed cell morphology from polygonal to triangular, and nucleus morphology from round to ellipsoid. PFF also reduced cell surface area (0.3-fold), cell volume (0.3-fold), and nucleus volume (0.2-fold). During PFF, the live-cell volume gradually decreased from 6000 to 3000 µm3. After PFF, α-tubulin orientation was more disorganized, but F-actin fluorescence intensity was enhanced, particularly around the nucleus. 3D-images obtained from Z-stacks indicated that PFF increased F-actin fluorescence signal distribution around the nucleus in the XZ and YZ direction (2.3-fold). PFF increased protein expression of phospho-paxillin (2.0-fold) and integrin-α5 (2.8-fold), but did not increase mRNA expression of paxillin-a (PXNA), paxillin-b (PXNB), integrin-α5 (ITGA51), or α-tubulin protein expression. In conclusion, PFF induced substantial changes in osteoblast cytoskeleton, as well as cell and nucleus morphology and volume, which was accompanied by elevated gene and protein expression of adhesion and structural proteins. More insights into the mechanisms whereby mechanical cues drive morphological changes in bone cells, and thereby, possibly in bone cell behavior, will aid the guidance of clinical treatment, particularly in the field of orthodontics, (oral) implantology, and orthopedics.
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Fischer, Edgar G. "Nuclear Morphology and the Biology of Cancer Cells". Acta Cytologica 64, n.º 6 (2020): 511–19. http://dx.doi.org/10.1159/000508780.
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<b><i>Background:</i></b> For more than a century, diagnostic pathologists have used morphologic abnormalities of the nucleus as essential diagnostic features to distinguish benign from malignant cells. These features include nuclear enlargement and increased nuclear-to-cytoplasmic ratio, nuclear membrane irregularities, hyperchromasia, and abnormal chromatin distribution. As our knowledge about the genetic and epigenetic abnormalities of cancer cells has increased in recent decades, the pathophysiologic mechanisms that underlie these morphologic abnormalities remain incompletely understood. <b><i>Summary:</i></b> This review attempts to summarize biologic abnormalities in malignant cells related to these morphologic changes. The molecular anatomy of the nuclear envelope in normal and malignant cells is discussed as well as regulation of nuclear size and shape, regulation of signal transduction pathways by molecules of the nuclear envelope, chromatin distribution, and the effects of HPV infection on dysplastic cells in the uterine cervix. <b><i>Key Message:</i></b> Causes of morphologic nuclear abnormalities in malignant cells are likely multifactorial. They probably include mutations, dysregulation of signal transduction pathways, abnormal gene expression patterns, alterations of nuclear envelope proteins and chromatin, and aneuploidy.
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Robinson, Christopher D., Michael S. Patton, Brittney M. Andre y Michele A. Johnson. "Convergent evolution of brain morphology and communication modalities in lizards". Current Zoology 61, n.º 2 (1 de abril de 2015): 281–91. http://dx.doi.org/10.1093/czoolo/61.2.281.
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Abstract Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals. Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals. For each species, we performed behavioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9–10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lateral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus). With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors.
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Giménez, Juliana. "Spermatogenesis and sperm morphology in Trophon geversianus (Gastropoda: Muricidae)". Journal of the Marine Biological Association of the United Kingdom 93, n.º 7 (4 de junio de 2013): 1881–86. http://dx.doi.org/10.1017/s0025315413000581.
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The ultrastructure of spermatogenesis, the euspermatozoa and paraspermatozoa, is investigated in Trophon geversianus. Spermatogenesis follows the general developmental pattern of caenogastropods. Paraspermatid development is characterized by elongation of the cell, concurrent with the appearance of a cytoplasmic elongation at the apex of the cell and the breakdown of the nucleus into small round fragments (caryomerites). Euspermatozoa consist of: a tall, conical acrosomal vesicle (with a invagination); a rod-shaped, highly electron-dense nucleus with an internal axoneme; an elongate midpiece consisting of the axoneme sheathed by helical mitochondrial elements; an elongate glycogen piece; and a short free-tail region. Paraspermatozoa of T. geversianus are vermiform. They contain approximately 12–16 axonemes arranged peripherally, numerous oblong dense vesicles, numerous less dense (round) vesicles, and scattered mitochondria. Most of the euspermatozoal features of T. geversianus are also observed in many neogastropods. However, the presence of the axoneme continuously located inside of the nucleus has not been reported before, and may prove to be a diagnostic feature of the Muricidae.
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Duric, Nebojsa y E. R. Seaquist. "Bipolar outflow of gas in the spiral galaxy NGC 3079". Canadian Journal of Physics 64, n.º 4 (1 de abril de 1986): 531–35. http://dx.doi.org/10.1139/p86-100.
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Very large array, radio-continuum observations of the edge-on spiral galaxy NGC 3079 are presented. The observations reveal that the nucleus has windlike properties and that the central region of the galaxy exhibits an unusual figure-eight morphology that shows evidence of severe depolarization and a flattening spectral index away from the nucleus. A qualitative description of a model is presented to account for the observed radio properties. It is shown that a wind-driven shock propagating away from the nucleus and focused by the ambient disk gas can give rise to the observed morphology.
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Boettcher, Barbara, Tatiana T. Marquez-Lago, Mathias Bayer, Eric L. Weiss y Yves Barral. "Nuclear envelope morphology constrains diffusion and promotes asymmetric protein segregation in closed mitosis". Journal of Cell Biology 197, n.º 7 (18 de junio de 2012): 921–37. http://dx.doi.org/10.1083/jcb.201112117.
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During vegetative growth, Saccharomyces cerevisiae cells divide asymmetrically: the mother cell buds to produce a smaller daughter cell. This daughter asymmetrically inherits the transcription factor Ace2, which activates daughter-specific transcriptional programs. In this paper, we investigate when and how this asymmetry is established and maintained. We show that Ace2 asymmetry is initiated in the elongated, but undivided, anaphase nucleus. At this stage, the nucleoplasm was highly compartmentalized; little exchange was observed for nucleoplasmic proteins between mother and bud. Using photobleaching and in silico modeling, we show that diffusion barriers compartmentalize the nuclear membranes. In contrast, the behavior of proteins in the nucleoplasm is well explained by the dumbbell shape of the anaphase nucleus. This compartmentalization of the nucleoplasm promoted Ace2 asymmetry in anaphase nuclei. Thus, our data indicate that yeast cells use the process of closed mitosis and the morphological constraints associated with it to asymmetrically segregate nucleoplasmic components.
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Fogle, Craig A., Joseph A. Rudnick, Alex J. Levine y Amy C. Rowat. "Transitions in Cell Nucleus Morphology Determined by Expression Levels of Nuclear Envelope Proteins". Biophysical Journal 102, n.º 3 (enero de 2012): 650a. http://dx.doi.org/10.1016/j.bpj.2011.11.3540.
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Lisovsky, Anatoly D., Nikita A. Popkovsky, Pavel S. Bobkov y Andrey V. Droblenkov. "Morphology of kisspeptin-producing nuclei in the rat hypothalamus". Medical academic journal 22, n.º 4 (1 de febrero de 2023): 69–76. http://dx.doi.org/10.17816/maj109714.
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ВACKGROUND: The article is devoted to the stereo-morphological analysis of the nuclei of the hypothalamus, synthesizing proteins of the kisspeptin family, regulating sexual differentiation various parts of the extended kisspeptin-producing nuclei of the hypothalamus and the features of their asymmetry in mature rats. The morphology of various parts of extended kisspeptin-producing nuclei of the hypothalamus remains poorly understood, which significantly complicates the choice of their reference zone, from which planning and implementation of morphological studies should begin, related to the evaluation of the effectiveness of therapeutic correction of various forms of hypogonadism.
AIM: Determination of the main source of regulatory peptides of the kisspeptin family based on the analysis of the number, area of neuron bodies and volumetric characteristics of the kisspeptin-producing nuclei of the hypothalamus.
MATERIALS AND METHODS: We studied 50 frontal paraffin sections of KPNs of 8 intact sexually mature male rats obtained as a result of a standard technique for their preparation and staining by the Nissl method. As a result, we carried out volumetric reconstruction of the largest nucleus of the arcuate complex the medial arcuate nucleus and the large periventricular nucleus, after which the number and area of neurosecretory cell bodies were determined in 5 frontal planes of these nuclei. To determine the proportion of kisspeptin-producing neurons in the total number of neurons in the kisspeptin-producing nuclei of the hypothalamus, we also performed the subsequent quantitative and morphometric characterization of their kisspeptin-producing neurons (after immunohistochemical staining, the identification of kisspeptin-kisspeptin granules. Statistical data processing was performed using the GraphPad PRISM 6.0 program, determining and lower quartiles. Differences were considered significant at p 0.01.
RESULTS: Subdivisions of the nuclei, which are the main source of these regulatory proteins, have been identified. The caudal part of the medial arcuate nucleus (at the level of bregma 3.6 mm) and the anterior part of the periventricular nucleus (at the level of bregma 0.2 mm) are subdivisions of the corresponding kisspeptin-producing nuclei of the hypothalamus of the kisspeptin-producing nuclei of the hypothalamus, containing the largest number of neurosecretory cells and the bodies of their largest largest area. The number and area of neurons in the left-sided and right-sided parts of the hypothalamic kisspeptin-producing nuclei of the hypothalamus did not differ significantly. In this regard, the listed left-sided and right-sided subdivisions of the kisspeptin-producing kisspeptin-producing nuclei of the hypothalamus of the were proposed as standards for their subsequent morphological studies, which are important for assessing the effectiveness of therapeutic correction of various forms of hypogonadism.
CONCLUSIONS: The left-sided and right-sided caudal parts of the medial arcuate hypothalamic nucleus and the anterior parts of the periventricular hypothalamic nucleus are proposed as a reference for their subsequent morphological studies related to the evaluation of the effectiveness of therapeutic correction of various forms of hypogonadism. as the main sources of regulatory proteins of the kisspeptin family.
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Santana, Júlio César de O., Daniela Calcagnotto y Irani Quagio-Grassiotto. "Sperm evolution in the family Alestidae with comparative data for the genus Chalceus (Ostariophysi: Characiformes)". Neotropical Ichthyology 12, n.º 2 (junio de 2014): 419–27. http://dx.doi.org/10.1590/1982-0224-20130177.
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Spermiogenesis and spermatozoa in six genera of the African family Alestidae plus the Neotropical genus Chalceusare described. Spermiogenesis is quite similar in all Alestidae and is identified as Type I and its variants. In Type I spermiogenesis, the flagellum of earliest spermatids lies lateral to the nucleus, and rotation of the nucleus towards the centriolar complex is observed. Nuclear rotation is complete reaching 90 degrees in Bryconalestes longipinnis, Brachypetersius altus, Brycinus imberi, B. lateralis, and Alestopetersius compressus; and is incomplete reaching 20 degrees in Micralestes acutidensand Rhabdalestesrhodesiensis. Spermatozoa morphology varies from a medial nucleus with fibrillar chromatin in the most basal genus Brycinusto a strongly eccentric nucleus with highly condensed chromatin in the more derived Rhabdalestesand Micralestes. Chalceushas a very similar spermatozoon to that found in Brycinussharing the fibrillar aspect of the chromatin in the nucleus. This feature is so far only observed in these two genera among African and Neotropical characiform fishes.
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Polosoro, A., W. Enggarini, T. Hadiarto y N. Ohmido. "Morphology changes of rice root nucleus under iron stress". IOP Conference Series: Earth and Environmental Science 383 (4 de diciembre de 2019): 012008. http://dx.doi.org/10.1088/1755-1315/383/1/012008.
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Palmer, A. R., M. N. Wallace, R. H. Arnott y T. M. Shackleton. "Morphology of physiologically characterised ventral cochlear nucleus stellate cells". Experimental Brain Research 153, n.º 4 (1 de diciembre de 2003): 418–26. http://dx.doi.org/10.1007/s00221-003-1602-6.
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Brunjes, Peter C. y Michael C. Kenerson. "The anterior olfactory nucleus: Quantitative study of dendritic morphology". Journal of Comparative Neurology 518, n.º 9 (1 de mayo de 2010): 1603–16. http://dx.doi.org/10.1002/cne.22293.
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Augustine, James R., Terrance Huntsberger y Michael Moore. "Computer-aided reconstructive morphology of the baboon abducens nucleus". Anatomical Record 212, n.º 2 (junio de 1985): 210–17. http://dx.doi.org/10.1002/ar.1092120217.
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Ketema, Mirjam, Maaike Kreft, Pablo Secades, Hans Janssen y Arnoud Sonnenberg. "Nesprin-3 connects plectin and vimentin to the nuclear envelope of Sertoli cells but is not required for Sertoli cell function in spermatogenesis". Molecular Biology of the Cell 24, n.º 15 (agosto de 2013): 2454–66. http://dx.doi.org/10.1091/mbc.e13-02-0100.
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Nesprin-3 is a nuclear envelope protein that connects the nucleus to intermediate filaments by interacting with plectin. To investigate the role of nesprin-3 in the perinuclear localization of plectin, we generated nesprin-3–knockout mice and examined the effects of nesprin-3 deficiency in different cell types and tissues. Nesprin-3 and plectin are coexpressed in a variety of tissues, including peripheral nerve and muscle. The expression level of nesprin-3 in skeletal muscle is very low and decreases during myoblast differentiation in vitro. Of interest, plectin was concentrated at the nuclear envelope in only a few cell types. This was most prominent in Sertoli cells of the testis, in which nesprin-3 is required for the localization of both plectin and vimentin at the nuclear perimeter. Testicular morphology and the position of the nucleus in Sertoli cells were normal, however, in the nesprin-3–knockout mice and the mice were fertile. Furthermore, nesprin-3 was not required for the polarization and migration of mouse embryonic fibroblasts. Thus, although nesprin-3 is critical for the localization of plectin to the nuclear perimeter of Sertoli cells, the resulting link between the nuclear envelope and the intermediate filament system seems to be dispensable for normal testicular morphology and spermatogenesis.
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Amalina, Rizki, Aulia Rohmania y Anggun Feranisa. "ANALYSIS OF SULFUR VAPOR EXPOSURE TO THE NUMBER OF MICRONUCLEUS AND ORAL BUCCAL EPITHELIAL MORPHOLOGY". Dentino : Jurnal Kedokteran Gigi 5, n.º 1 (12 de marzo de 2020): 90. http://dx.doi.org/10.20527/dentino.v5i1.8130.
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Background: The sulfur vapor consists of SO2 and CO2 which are genotoxins that may cause the damage of DNA to the micronucleus in buccal epithelial cells. Micronucleus is a mass like a nucleus, measuring one-third of the nucleus. DNA damage can also be seen from changes in the morphology of epithelial cells. Objective: This study aimed to identify the effect of sulfur vapor exposure on the number of micronucleus and morphology epithelial cells in the oral cavity on the sulfur miner. Methods: The method of this study was analytic observational with a cross-sectional approach. The total sample of this study was 24 respondents divided into 2 groups, each group contained 12 respondents. Exfoliated buccal cells were collected by scrapping the buccal mucosa. The specimens stained using Hematoxylin and Eosin. Nucleus and cytoplasmic area were examined using image J 1.40 Results: The result showed the average number of buccal mucosa micronucleus on coal miners higher (35,50) than controls (11,58). The result of Independent-measures T-test obtained significant different on the number of micronucleus between sulfur miner and controls (p=0,000). The result of Independent-measures T-test on the nuclear area and cytoplasmic area between sulfur miner and controls obtained insignificant different (p=0,379 dan p=0,616). Conclusion: Based on this study can be concluded that sulfur vapor exposure affected on the number of micronucleus on sulfur miners, but did not influence morphology of epithelial cells.
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Misteli, T. "Cell biology of transcription and pre-mRNA splicing: nuclear architecture meets nuclear function". Journal of Cell Science 113, n.º 11 (1 de junio de 2000): 1841–49. http://dx.doi.org/10.1242/jcs.113.11.1841.
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Gene expression is a fundamental cellular process. The basic mechanisms involved in expression of genes have been characterized at the molecular level. A major challenge is now to uncover how transcription, RNA processing and RNA export are organized within the cell nucleus, how these processes are coordinated with each other and how nuclear architecture influences gene expression and regulation. A significant contribution has come from cell biological approaches, which combine molecular techniques with microscopy methods. These studies have revealed that the mammalian cell nucleus is a complex but highly organized organelle, which contains numerous subcompartments. I discuss here how two essential nuclear processes - transcription and pre-mRNA splicing - are spatially organized and coordinated in vivo, and how this organization might contribute to the control of gene expression. The dynamic nature of nuclear proteins and compartments indicates a high degree of plasticity in the cellular organization of nuclear functions. The cellular organization of transcription and splicing suggest that the morphology of nuclear compartments is largely determined by the activities of the nucleus.
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Kirchenbauer, Marisa y Dimitris Liakopoulos. "An auxiliary, membrane-based mechanism for nuclear migration in budding yeast". Molecular Biology of the Cell 24, n.º 9 (mayo de 2013): 1434–43. http://dx.doi.org/10.1091/mbc.e12-08-0602.
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How nuclear shape correlates with nuclear movements during the cell cycle is poorly understood. We investigated changes in nuclear morphology during nuclear migration in budding yeast. In preanaphase cells, nuclear protrusions (nucleopodia [NP]) extend into the bud, preceding insertion of chromosomes into the bud neck. Surprisingly, formation of nucleopodia did not depend on the established nuclear migration pathways. We show that generation and maintenance of NP requires nuclear membrane expansion, actin, and the exocyst complex. Exocyst mutations cause nuclear positioning defects and display genetic interactions with mutations that deactivate astral microtubule-dependent nuclear migration. Cells that cannot perform DNA replication also fail to form nucleopodia. We propose that nuclear membrane expansion, DNA replication, and exocyst-dependent anchoring of the nuclear envelope to the bud affect nuclear morphology and facilitate correct positioning of nucleus and chromosomes relative to the cleavage apparatus.
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Sazdanovic, Maja, Slobodanka Mitrovic, Milos Todorovic, Maja Vulovic, Dejan Jeremic, Zoran Milosavljevic, Predrag Sazdanovic y Neda Ognjanovic. "Morphology of Human Nucleus Accumbens Neurons Based on the Immunohistochemical Expression of Gad67". Serbian Journal of Experimental and Clinical Research 17, n.º 4 (1 de diciembre de 2016): 297–302. http://dx.doi.org/10.1515/sjecr-2016-0041.
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Abstract The nucleus accumbens is a part of the ventral striatum along with the caudate nucleus and putamen. The role of the human nucleus accumbens in drug addiction and other psychiatric disorders is of great importance. The aim of this study was to characterize medium spiny neurons in the nucleus accumbens according to the immunohistochemical expression of GAD67. This study was conducted on twenty human brains of both sexes between the ages of 20 and 75. The expression of GAD67 was assessed immunohistochemically, and the characterization of the neurons was based on the shape and size of the soma and the number of impregnated primary dendrites. We showed that neurons of the human nucleus accumbens expressed GAD67 in the neuron soma and in the primary dendrites. An analysis of the cell body morphology revealed the following four different types of neurons: fusiform neurons, fusiform neurons with lateral dendrites, pyramidal neurons and multipolar neurons. An immunohistochemical analysis showed a strong GAD67 expression in GABAergic medium spiny neurons, which could be classifi ed into four different types, and these neurons morphologically correlated with those described by the Golgi study.
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Stepanchuk, A. P. "MORPHOLOGY OF HUMAN ADIPOSE TISSUE". Актуальні проблеми сучасної медицини: Вісник Української медичної стоматологічної академії 20, n.º 2 (6 de julio de 2020): 171–75. http://dx.doi.org/10.31718/2077-1096.20.2.171.
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The risk of developing metabolic complications in obesity depends on the topography of excess adipose tissue. Adipose tissue is the main source of energy and also performs an endocrine function secreting substances that affect the sensitivity of tissues to insulin. The article describes the characteristics of histological preparations of adipose tissue samples taken from the omentum of middle-aged human cadavers with no confirmed diseases of the digestive system and of subcutaneous adipose tissue samples from interscapular region in the human dead foetuses. Microscopy of sections of adipose tissue from the omentum and subcutaneous adipose tissue from the interscapular region of the foetus revealed that it consisted of lobes and microvessels. Lobes of adipose tissue of a human large omentum consist of polygonal white adipocytes containing in their cytoplasm a nucleus displaced to the periphery and a fat drop. The subcutaneous adipose tissue taken from the interscapular region of the foetus consists of brown adipocytes with a nucleus located in the centre of the cytoplasm and surrounded by numerous fat droplets. Brown adipocytes when compared with white adipocyted are smaller and rounded in shape. Brown adipose tissue predominates in women than in men. Brown adipose tissue is not active all the time, but only at low ambient temperatures. In women, brown adipocytes are more saturated with mitochondria than in men. Adipose tissue of a human omentum can be a source of graft implant for restoring abdominal organ defects during extensive surgical operations.
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Hutchings, J. B. y S. G. Neff. "Morphology and Spectroscopy of Markarian 231". Symposium - International Astronomical Union 121 (1987): 399–401. http://dx.doi.org/10.1017/s007418090015541x.
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Deep optical imaging of Mkn 231 reveals twin (tidal?) tails, a linear nuclear feature at green wavelengths, and a very blue region 4 arcsec south of the nucleus. Much of the central part of the galaxy is red, but there are complex areas of blue luminosity outside this, and a sharp edge to the luminosity at a distance of ~16 arcsec from the centre. Overall, the host galaxy appears to have a normal optical luminosity and blue colour (B-R ~0.7) despite being one of the most luminous galaxies known in the infrared. Radio emission in the system is extended on one side on a similar scale to the optical tails, but shows no detailed correspondence with optical structure; in particular there is no radio counterpart to the optical ‘jet’. Examination of IUE archival data indicate that the UV flux is very weak and the UV spectrum is peculiar for a Seyfert galaxy. The UV observations provide evidence for considerable nuclear extinction in the system, in accordance with previously published optical and infrared work, but the UV extinction is unlike Galactic absorption and may be more similar to that seen in the LMC. Recent optical spectra of Mkn 231 show changes in both the emission line spectrum and in the strong broad absorption lines (BAL), compared with previously published observations. This places strong limitations on the size of the nuclear continuum source. We suggest that Mkn 221 is a recently merged system which is currently undergoing star-formation, and discuss the connection with BAL QSOs.
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Abel, John, Suyog Jain, Deepta Rajan, Ken Leidal, Harshith Padigela, Aaditya Prakash, Jake Conway et al. "Abstract 464: AI-powered segmentation and analysis of nuclei morphology predicts genomic and clinical markers in multiple cancer types". Cancer Research 82, n.º 12_Supplement (15 de junio de 2022): 464. http://dx.doi.org/10.1158/1538-7445.am2022-464.
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Abstract Morphological features of cancer cell nuclei are linked to gene expression signatures and genomic alterations. In addition, pathologists have leveraged nuclear morphology as diagnostic and prognostic markers. To enable the use of nuclear morphology in digital pathology, we developed a pan-tissue, deep-learning-based digital pathology pipeline for exhaustive nucleus detection, instance segmentation, and classification. We collected > 29,000 manual nucleus annotations from hematoxylin and eosin (H&E)-stained pathology images from 21 tumor types at 40x and 20x magnification from The Cancer Genome Atlas (TCGA) project, as well as a proprietary set of H&E-stained tissue biopsies of skin, liver non-alcoholic steatohepatitis (NASH), colon inflammatory bowel disease (IBD), and kidney lupus. Annotations were used to train an object detection and segmentation model for identifying nuclei. Application of the model to held-out test data, including held-out tissue types, demonstrated performance comparable to state-of-the-art models described in the literature (mean Dice score = 0.80, aggregated Jaccard index = 0.60). We deployed our model to segment nuclei in H&E slides from the breast cancer (BRCA, N = 941) and prostate adenocarcinoma (PRAD, N = 457) TCGA cohorts. We extracted interpretable features describing the shape (circularity, eccentricity), size, staining intensity (mean and standard deviation), and texture of each nucleus. Nuclei were assigned as cancer or other cell types using separately trained convolutional neural networks for BRCA and PRAD. We used the mean and standard deviation of each feature sampled from a random subset of cancer nuclei to summarize the nuclear morphology on each slide (mean (range) = 10,068 (5,981-10,452) cancer cells from each BRCA slide; mean (range) = 10,053 (5,029-10,495) cancer cells from each PRAD slide). We used nuclear features to construct random forest classification models for predicting markers of genomic instability and prognosis: whole-genome doubling (WGD) and homologous recombination deficiency (HRD) status separately in BRCA and PRAD, HER2 subtype in BRCA, and Gleason grade in PRAD. Nuclear features were predictive of WGD (area under the receiver operating characteristic curve (AUROC) = 0.78 BRCA, = 0.69 PRAD) and binarized HRD status (AUROC = 0.65 BRCA, = 0.68 PRAD) on held-out test sets. Nuclear features were predictive of HER2-enriched breast cancer vs. other molecular subtypes (AUROC = 0.72), and distinguished between low risk (6) and moderate/high risk (7-10) Gleason grade in PRAD (AUROC = 0.72). In summary, we present a powerful pan-tissue approach for nucleus segmentation and featurization, which enables the construction of predictive models and the identification of features linking nuclear morphology with clinically-relevant prognostic biomarkers across multiple cancer types. Citation Format: John Abel, Suyog Jain, Deepta Rajan, Ken Leidal, Harshith Padigela, Aaditya Prakash, Jake Conway, Michael Nercessian, Christian Kirkup, Robert Egger, Ben Trotter, Andrew Beck, Ilan Wapinski, Michael G. Drage, Limin Yu, Amaro Taylor-Weiner. AI-powered segmentation and analysis of nuclei morphology predicts genomic and clinical markers in multiple cancer types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 464.
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Obady, Yaser H. A. y Ola A. A. Alareeqi. "ERYTHROCYTES COUNTS AND MORPHOLOGY OF ACANTOCERCUS ADRAMITANUS AND CHAMELEO CALYPTRATUS CALYPTRATUS FROM YEMEN". Electronic Journal of University of Aden for Basic and Applied Sciences 1, n.º 3 (30 de septiembre de 2020): 167–74. http://dx.doi.org/10.47372/ejua-ba.2020.3.40.
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The aim of this study was to determine the erythrocyte and nucleus morphology of Acantocercus adramitanus and Chameleo calyptratus calyptratus from Yemen by means of blood smears stained with Giemsa stain. The longest and largest erythrocytes and their nucleus were observed in the smears of C. c. calyptratus, while the narrowest and smallest in A. adramitanus. In terms of the studied species, the nucleus and erythrocyte sizes were found to be correlated. No significant difference between two species lizard’s in erythrocyte count was determined. The relationship between the raw erythrocyte measurements and erythrocyte length was determined as positive correlation.
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Coscarella, Isabella Leite, Maicon Landim-Vieira, Hosna Rastegarpouyani, Prescott Bryant Chase, Jerome Irianto y Jose Renato Pinto. "Nucleus Mechanosensing in Cardiomyocytes". International Journal of Molecular Sciences 24, n.º 17 (28 de agosto de 2023): 13341. http://dx.doi.org/10.3390/ijms241713341.
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Cardiac muscle contraction is distinct from the contraction of other muscle types. The heart continuously undergoes contraction–relaxation cycles throughout an animal’s lifespan. It must respond to constantly varying physical and energetic burdens over the short term on a beat-to-beat basis and relies on different mechanisms over the long term. Muscle contractility is based on actin and myosin interactions that are regulated by cytoplasmic calcium ions. Genetic variants of sarcomeric proteins can lead to the pathophysiological development of cardiac dysfunction. The sarcomere is physically connected to other cytoskeletal components. Actin filaments, microtubules and desmin proteins are responsible for these interactions. Therefore, mechanical as well as biochemical signals from sarcomeric contractions are transmitted to and sensed by other parts of the cardiomyocyte, particularly the nucleus which can respond to these stimuli. Proteins anchored to the nuclear envelope display a broad response which remodels the structure of the nucleus. In this review, we examine the central aspects of mechanotransduction in the cardiomyocyte where the transmission of mechanical signals to the nucleus can result in changes in gene expression and nucleus morphology. The correlation of nucleus sensing and dysfunction of sarcomeric proteins may assist the understanding of a wide range of functional responses in the progress of cardiomyopathic diseases.
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Sur, M., M. Esguerra, P. E. Garraghty, M. F. Kritzer y S. M. Sherman. "Morphology of physiologically identified retinogeniculate X- and Y-axons in the cat". Journal of Neurophysiology 58, n.º 1 (1 de julio de 1987): 1–32. http://dx.doi.org/10.1152/jn.1987.58.1.1.
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1.We studied the morphology of individual, physiologically identified retinogeniculate axons in normal adult cats. The axons were recorded in the lateral geniculate nucleus or in the subjacent optic tract, characterized as X or Y by physiological criteria, penetrated, and injected with horseradish peroxidase. With subsequent application of appropriate histochemistry, the enzyme provides a complete label of the terminal arbors and parent trunks for morphological analysis. We have recovered for such analysis 26 X- and 25 Y-axons; of these, 14 X- and 12 Y-axons were studied in detail. 2. Within the optic tract, the parent trunk of every X-axon is located closer to the lateral geniculate nucleus and thus further from the pial surface than that of every Y-axon. This probably reflects the earlier development of X- than of Y-axons. Furthermore, the parent axon trunks of the X-axons are noticeably thinner than are those of the Y-axons. Every retinogeniculate X- and Y-axon in our sample branches within the optic tract. One of these branches heads dorsally to innervate the lateral geniculate nucleus and one heads medially and rostrally toward the midbrain, although none of these labeled axons were traced to a terminal arbor beyond the lateral geniculate nucleus. For Y-axons, all branches are of comparable diameter, but for X-axons, the branch heading toward the lateral geniculate nucleus is always noticeably thicker than is the branch directed toward the midbrain. 3. Every retinogeniculate X- and Y-axon produces the greatest portion of its terminal arbor in lamina A (if from the contralateral retina) or A1 (if from the ipsilateral retina). These arbors typically extend across most of the lamina along a projection line. Not a single terminal bouton from any axon was found in the inappropriate lamina A or A1 (i.e., in lamina A for ipsilaterally projecting axons or in lamina A1 for contralaterally projecting ones). Occasionally, an X-axon also innervates the medial interlaminar nucleus, and even more rarely does an X-axon innervate the C-laminae. In contrast, nearly all Y-axons from the contralateral retina branch to innervate part of the C-laminae (probably lamina C), and most from either retina also innervate the medial interlaminar nucleus. Although these details imply considerable variation in the overall pattern of retinogeniculate innervation for both X- and Y-axons, we found no physiological properties to correlate with this variation.(ABSTRACT TRUNCATED AT 400 WORDS)
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Frye, Keyada, Fioranna Renda, Maria Fomicheva, Xiaodong Zhu, Lisa Gong, Alexey Khodjakov y Irina Kaverina. "Cell Cycle-Dependent Dynamics of the Golgi-Centrosome Association in Motile Cells". Cells 9, n.º 5 (25 de abril de 2020): 1069. http://dx.doi.org/10.3390/cells9051069.
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Here, we characterize spatial distribution of the Golgi complex in human cells. In contrast to the prevailing view that the Golgi compactly surrounds the centrosome throughout interphase, we observe characteristic differences in the morphology of Golgi ribbons and their association with the centrosome during various periods of the cell cycle. The compact Golgi complex is typical in G1; during S-phase, Golgi ribbons lose their association with the centrosome and extend along the nuclear envelope to largely encircle the nucleus in G2. Interestingly, pre-mitotic separation of duplicated centrosomes always occurs after dissociation from the Golgi. Shortly before the nuclear envelope breakdown, scattered Golgi ribbons reassociate with the separated centrosomes restoring two compact Golgi complexes. Transitions between the compact and distributed Golgi morphologies are microtubule-dependent. However, they occur even in the absence of centrosomes, which implies that Golgi reorganization is not driven by the centrosomal microtubule asters. Cells with different Golgi morphology exhibit distinct differences in the directional persistence and velocity of migration. These data suggest that changes in the radial distribution of the Golgi around the nucleus define the extent of cell polarization and regulate cell motility in a cell cycle-dependent manner.