Download or read book Identification of Regulatory Factors that Control Nervous System Form Function and Regeneration in the Planarian Schmidtea Mediterranea written by Martis William Cowles and published by . This book was released on 2014 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neurons are born from stem cells, migrate to their final location, form synaptic connections, and terminally differentiate by a process known as neurogenesis. Although this phenomenon is observed in adult organisms across metazoans, most animals lack the ability to repair catastrophic damages to the central nervous system (CNS) caused by injury, disease or aging. By contrast, planarians have the amazing ability to regenerate all tissue types (including the CNS) from a population of pluripotent adult stem cells they maintain throughout their life, making these animals a powerful system to research stem cell-based regeneration in vivo. To investigate how adult stem cells are directed to generate new neurons during CNS regeneration, we examined the basic helix-loop-helix (bHLH) transcription factor family in planarians. Many bHLH family members regulate neurogenesis during development and are associated with nervous system diseases, yet their functions in adult stem cells and mature neurons remain unclear. We identified 44 planarian bHLH homologs, determined their tissue-specific expression in the adult animal, and examined their function using RNA interference. These analyses identified nine bHLHs expressed in stem cells and neurons that were required for CNS regeneration, including homologs of Collier/Olfactory-1/Early B-cell factor (coe), Single-minded (sim), and Hairy enhancer of split (hesl-3). Furthermore, we demonstrated that coe, sim and hesl-3 mRNA were detected in lineage-committed progenitors. Our functional screen revealed that gene silencing of coe results in CNS regeneration defects. COE genes play conserved roles in nervous system development and are associated with CNS diseases; however, the genetic programs downstream of these genes remain largely unknown. By comparing the transcriptome profiles of control and coe-deficient animals, we identified over 900 differentially expressed genes, including 397 downregulated genes enriched for CNS functions. We examined downregulated genes and identified new targets of COE in mature neurons, some of which were required for CNS regeneration. Furthermore, we found novel genes expressed in stem cell progeny that function downstream of COE and were critical for stem cell homeostasis. These findings demonstrate that COE regulates genetic programs essential for CNS homeostasis and regeneration, providing insights into how COE proteins function in the adult nervous system.
Download or read book Regeneration and Maintenance of the Planarian Nervous System written by Sylvain William Lapan and published by . This book was released on 2012 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Planarians can regenerate all tissues, including the central nervous system and the eyes. This process depends on a population of cells in the adult, the neoblasts, that includes pluripotent stem cells. Whether the neoblast population also includes progenitors specialized for forming specific lineages has not been demonstrated. This thesis describes the identification of progenitors that contribute to eyes during regeneration. Expression and functional analyses identified the genes eyes absent, six- 1/2 and ovo as critical for the formation of all cells of the eye. otxA and soxB were specifically required for photoreceptor regeneration, and sp6-9 and dlx were required for regeneration of the optic pigment cup. Expression analysis of these transcription factors in situ revealed that eye progenitors were distributed in mesenchymal trails extending posteriorly from the regenerating eye. These progenitors originate in the neoblasts, and promixity to the eye primordium correlates with increased differentiation. The spatial and genetic identification of a progenitor population in planarians elucidates migratory and morphogenetic mechanisms underlying organ regeneration in these animals. RNA sequencing of eye tissue also identified hundreds of genes with highly enriched expression in the eye, including numerous orthologs of eye pathology-related gene as well as likely components of key visual processes such as phototransduction and optic pigment cell function. The planarian brain is composed of dozens of cell types with regionalized distribution. The function of the planarian hedgehog gene in the patterning of CNS regions was investigated. hedgehog was expressed in the medial planarian brain, flanked by nkx2 and nkx6, then pax6b, and finally dlx-1 and msx at the most distal positions. This organization is similar to the expression domains of orthologous transcription factors in the vertebrate neural tube. However, in contrast to vertebrates, the expression of nkx2, nkx6, and pax6b in planarians was not affected by loss of hedgehog expression. RNA sequencing analysis identified a strong effect of Hedgehog signaling genes on a medially positioned cell with glia-like features. Therefore, Hedgehog signaling affects formation of at least one cell type in the planarian brain, but does not broadly regulate transcription factor expression domains and cell type identity.
Download or read book Transcriptional and Epigenetic Regulation of Axon Regeneration written by Marcus Mahar and published by . This book was released on 2019 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mammalian nervous system is a highly intricate network consisting of over a hundred billion specialized cells called neurons. One unique characteristic of neurons is their highly polarized morphology; unlike other cells, neurons project long axonal extensions. These structures allow them to connect and communicate with not only other neurons, but also various cell types in the body and give rise to all motor, sensory, and higher order function. Because axons can extend up to three feet, they are also vulnerable to injury from sources such as traumatic brain and spinal cord injuries, stroke, or neurodegenerative diseases. Indeed, patients who have experienced these injuries often suffer debilitating, irreversible loss of function. Interestingly, whereas neurons which reside in the central nervous system are incapable of regenerating after axon injury, neurons of the peripheral nervous system activate a robust pro-regenerative response capable of promoting long distance regeneration and functional recovery. The molecular mechanisms which underlie this pro-regenerative response may provide key insights into how a pro-regenerative response could be stimulated in injured central nervous system neurons. A comprehensive overview of the known molecular mechanisms involved in this response is reviewed in Chapter 1.As mammals age, the synaptic connections between neurons mature. Following axon injury in peripheral nervous system neurons, the genes involved in synaptic function are turned off and genes required for inducing axon growth are activated. These widespread epigenetic and transcriptional changes require a coordinated effort of epigenetic and transcriptional regulators including epigenetic modifiers, transcription factors, and microRNAs. In Chapter 2, we demonstrated that these changes are, in part, a result of the rapid downregulation of microRNA-9 which occurs following axon injury. At baseline in adult peripheral nervous system neurons, microRNA-9 is highly expressed and actively represses various genes including REST and UHRF1. When microRNA-9 expression decreases following injury, both REST and UHRF1 increase with UHRF1also repressing REST and restricting REST expression to a tight temporal window. During this time, REST binds to and represses various genes involved in synaptic function such as ion channels; a process necessary for peripheral nervous system regeneration. This complete published work can be found in Chapter 2.In coordination with epigenetic modifiers such as UHRF1, various transcription factors are activated following axon injury and promote the expression of pro-growth genes. Various studies have worked to identify the transcription factors involved in this process as exogenous overexpression of transcription factors has been shown to confer specific phenotypes of interest, such as the conversion of one cell type to another, when the correct combination of transcription factors is manipulated. To further this work, in Chapter 3 I used bioinformatics analysis to identify 27 transcription factors putatively involved in the establishment of the pro-regenerative response. Using two complimentary in vitro screens, determined which transcription factors were both necessary for peripheral nervous system axon regeneration and sufficient to drive central nervous system axon regeneration. By pairing these results with network-based bioinformatics analysis, we identified Creb1 as a transcription factor which sits atop the pro-regenerative gene regulatory network. Follow-up studies in which we overexpressed Creb1during optic nerve regeneration demonstrated Creb1 is sufficient to promote central nervous system axon regeneration in vivo. This work provides exciting new insight into the various transcription factors regulating this response as well as their putative genetic relationships.
Download or read book Experimental Studies of the Regeneration of Planaria Maculata written by Thomas Hunt Morgan and published by . This book was released on 1898 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Invertebrates written by Libbie Henrietta Hyman and published by . This book was released on 1951 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Oxford Handbook of Invertebrate Neurobiology written by John H. Byrne and published by Oxford University Press. This book was released on 2019-01-29 with total page 1304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Invertebrates have proven to be extremely useful model systems for gaining insights into the neural and molecular mechanisms of sensory processing, motor control and higher functions such as feeding behavior, learning and memory, navigation, and social behavior. A major factor in their enormous contributions to neuroscience is the relative simplicity of invertebrate nervous systems. In addition, some invertebrates, primarily the molluscs, have large cells, which allow analyses to take place at the level of individually identified neurons. Individual neurons can be surgically removed and assayed for expression of membrane channels, levels of second messengers, protein phosphorylation, and RNA and protein synthesis. Moreover, peptides and nucleotides can be injected into individual neurons. Other invertebrate model systems such as Drosophila and Caenorhabditis elegans offer tremendous advantages for obtaining insights into the neuronal bases of behavior through the application of genetic approaches. The Oxford Handbook of Invertebrate Neurobiology reviews the many neurobiological principles that have emerged from invertebrate analyses, such as motor pattern generation, mechanisms of synaptic transmission, and learning and memory. It also covers general features of the neurobiology of invertebrate circadian rhythms, development, and regeneration and reproduction. Some neurobiological phenomena are species-specific and diverse, especially in the domain of the neuronal control of locomotion and camouflage. Thus, separate chapters are provided on the control of swimming in annelids, crustaea and molluscs, locomotion in hexapods, and camouflage in cephalopods. Unique features of the handbook include chapters that review social behavior and intentionality in invertebrates. A chapter is devoted to summarizing past contributions of invertebrates to the understanding of nervous systems and identifying areas for future studies that will continue to advance that understanding.
Download or read book Regeneration written by Thomas Hunt Morgan and published by . This book was released on 1901 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Building the Most Complex Structure on Earth written by Nelson R Cabej and published by Newnes. This book was released on 2013-04-01 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building the Most Complex Structure on Earth provides readers with a basic biological education an easy and understandable introduction into a new epigenetic theory of development and evolution. This is a novel theory that describes the epigenetic mechanisms of the development and evolution of animals and explains the colossal evolution and diversification of animals from a new post-genetic perspective. Modern biology has demonstrated the existence of a common genetic toolkit in the animal kingdom, but neither the number of genes nor the evolution of new genes is responsible for the development and evolution of animals. The failure to understand how the same genetic toolkit is used to produce millions of widely different animal forms remains a perplexing conundrum in modern biology. The novel theory shows that the development and evolution of the animal kingdom are functions of epigenetic mechanisms, which are the competent users of the genetic toolkit. - Provides a comprehensive view of the epigenetic aspects of reproduction, development, and evolution. - Highly rigorous, but simple enough for readers with only a basic knowledge of biology.
Download or read book The Biology of Reproduction written by Giuseppe Fusco and published by Cambridge University Press. This book was released on 2019-10-10 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: A look into the phenomena of sex and reproduction in all organisms, taking an innovative, unified and comprehensive approach.
Download or read book Reproductive and Developmental Strategies written by Kazuya Kobayashi and published by Springer. This book was released on 2018-06-01 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides new insights into the universality of biological systems in animal reproduction and development by a comparative study of a variety of mechanisms in animals ranging from basal invertebrates to vertebrates, including mammals. Animals accomplish genetic diversity through meiosis and fertilization, and during embryogenesis animals must produce specialized cell types, including germ cells, in accordance with their individual body plan. This series of phenomena is essential to the continuity of life in the animal kingdom, and animals show various reproductive and developmental strategies. This volume, comprising four parts, reviews animal kingdom diversity, including reproductive strategies and germ cell differentiation mechanisms (Part 1), sex determination and differentiation (Part2), the mechanisms of fertilization (Part 3), and body axis formation (Part 4). Readers will find descriptions of the reproduction or development of 180 species, 13 phyla, 35 classes, 74 orders, 117 families, and 151 genera in this book. Of particular interest is the diversity of molecules and mechanisms used to achieve the same biological purpose in different animals. Undergraduates, graduate students, and professional scientists who want a deeper understanding of animal reproductive and developmental mechanisms will find this book to be of great value.
Download or read book Stem Cells in Marine Organisms written by Baruch Rinkevich and published by Springer Science & Business Media. This book was released on 2009-10-03 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Do real stem cells and stem cell lineages exist in lower organisms? Can stem cells from one organism parasitize the soma and/or the germ line of conspecifics? Can differentiated cells in marine organisms be re-programmed to regenerate tissues, organs and appendages through novel de-differentiation, transdifferentiation, or re-differentiation processes, leading to virtually all three germ layers, including the germline? The positive answers to above questions open a new avenue in stem cell research: the biology of stem cells in marine organisms. It is therefore unfortunate that while the literature on stem cell from terrestrial organisms is rich and expanding at an exponential rate, investigations on marine organisms’ stem cells are very limited and scarce. By presenting theoretical chapters, overview essays and specific research results, this book summarises the knowledge and the hypotheses on stem cells in marine organisms through major phyla and specific model organisms. The study on stem cells from marine invertebrates may shed lights on mechanisms promoting immunity, developmental biology, regeneration and budding processes in marine invertebrates, body maintenance, aging and senescence. It aims in encouraging a larger scientific community to follow and study the novel phenomena of stem cells behaviours as depicted from the few currently studied marine invertebrates.
Download or read book Translational Control of Gene Expression written by Nahum Sonenberg and published by CSHL Press. This book was released on 2001 with total page 1034 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the 1996 publication of Translational Control, there has been fresh interest in protein synthesis and recognition of the key role of translation control mechanisms in regulating gene expression. This new monograph updates and expands the scope of the earlier book but it also takes a fresh look at the field. In a new format, the first eight chapters provide broad overviews, while each of the additional twenty-eight has a focus on a research topic of more specific interest. The result is a thoroughly up-to-date account of initiation, elongation, and termination of translation, control mechanisms in development in response to extracellular stimuli, and the effects on the translation machinery of virus infection and disease. This book is essential reading for students entering the field and an invaluable resource for investigators of gene expression and its control.
Download or read book The Invertebrates Platyhelminthes and Rhynchocoela the acoelomate Bilateria written by Libbie Henrietta Hyman and published by . This book was released on 1940 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book RUNX Proteins in Development and Cancer written by Yoram Groner and published by Springer. This book was released on 2017-03-15 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides the reader with an overview of the diverse functions of the RUNX family of genes. As highlighted in the introduction and several of the 29 chapters, humans and other mammals have three RUNX genes that are known to play specific roles in blood, bone and neuronal development. However, their evolutionary history has recently been traced back to unicellular organisms and their involvement in many well-known signaling pathways (Wnt, TGFb, Notch, Hippo) is indicative of a more general function in cell biology. Their documented roles in cell fate decisions include control of proliferation, differentiation, survival, senescence and autophagy. The pleiotropic effects of RUNX in development are mirrored in cancer, where RUNX genes can function as oncogenes that collaborate strongly with Myc family oncogenes or as tumour suppressor genes. In the latter role, they display hallmarks of both ‘gatekeepers’ that modulate p53 responses and ‘caretakers’ that protect the genome from DNA damage. Several chapters focus on the importance of these genes in leukemia research, where RUNX1 and CBFB are frequently affected by chromosomal translocations that generate fusion oncoproteins, while recent studies suggest wider roles for RUNX modulation in solid cancers. Moreover, RUNX genes are intimately involved in the development and regulation of the immune system, while emerging evidence suggests a role in innate immunity to infectious agents, including HIV. At the biochemical level, the RUNX family can serve as activators or repressors of transcription and as stable mediators of epigenetic memory through mitosis. Not surprisingly, RUNX activity is controlled at multiple levels, this includes miRNAs and a plethora of post-translational modifications. Several chapters highlight the interplay between the three mammalian RUNX genes, where cross-talk and partial functional redundancies are evident. Finally, structural analysis of the RUNX/CBFB interaction has led to the development of small molecule inhibitors that provide exciting new tools to decipher the roles of RUNX in development and as targets for therapy. This volume provides a compendium and reference source that will be of broad interest to cancer researchers, developmental biologists and immunologists.
Download or read book Cellular Dedifferentiation and Regenerative Medicine written by Xiaobing Fu and published by Springer. This book was released on 2018-02-09 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the contribution of cell dedifferentiation to the regenerative process in all body systems, as well as its underlying molecular mechanisms and applications. The book is divided into four parts, the first of which addresses the history of cell dedifferentiation and regenerative medicine. In turn, Part II compares three routes by which cells change their phenotype: dedifferentiation, transdifferentiation, and reprogramming. Part III includes an extensive review of cell dedifferentiation events in all nine body systems for lower organisms and mammalians, respectively. The final part reviews the relationship between cell dedifferentiation and the development of cancer and several other diseases, while also outlining the prospects of and future research directions in cell dedifferentiation and regenerative medicine. The main purpose of the book is to underline the importance of cell dedifferentiation in stem cell and regenerative medicine by providing a systematical review of dedifferentiation in all body systems, together with the latest reliable evidence.
Download or read book Cell Engineering and Regeneration written by Heinz Redl and published by Springer. This book was released on 2017-02-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference work presents the origins of cells for tissue engineering and regeneration, including primary cells, tissue-specific stem cells, pluripotent stem cells and trans-differentiated or reprogrammed cells. There is particular emphasis on current understanding of tissue regeneration based on embryology and evolution studies, including mechanisms of amphibian regeneration. The book covers the use of autologous versus allogeneic cell sources, as well as various procedures used for cell isolation and cell pre-conditioning , such as cell sorting, biochemical and biophysical pre-conditioning, transfection and aggregation. It also presents cell modulation using growth factors, molecular factors, epigenetic approaches, changes in biophysical environment, cellular co-culture and other elements of the cellular microenvironment. The pathways of cell delivery are discussed with respect to specific clinical situations, including delivery of ex vivo manipulated cells via local and systemic routes, as well as activation and migration of endogenous reservoirs of reparative cells. The volume concludes with an in-depth discussion of the tracking of cells in vivo and their various regenerative activities inside the body, including differentiation, new tissue formation and actions on other cells by direct cell-to-cell communication and by secretion of biomolecules.
Download or read book Advances in Comparative Immunology written by Edwin L. Cooper and published by Springer. This book was released on 2018-08-07 with total page 1063 pages. Available in PDF, EPUB and Kindle. Book excerpt: Immunologists, perhaps understandably, most often concentrate on the human immune system, an anthropocentric focus that has resulted in a dearth of information about the immune function of all other species within the animal kingdom. However, knowledge of animal immune function could help not only to better understand human immunology, but perhaps more importantly, it could help to treat and avoid the blights that affect animals, which consequently affect humans. Take for example the mass death of honeybees in recent years – their demise, resulting in much less pollination, poses a serious threat to numerous crops, and thus the food supply. There is a similar disappearance of frogs internationally, signaling ecological problems, among them fungal infections. This book aims to fill this void by describing and discussing what is known about non-human immunology. It covers various major animal phyla, its chapters organized in a progression from the simplest unicellular organisms to the most complex vertebrates, mammals. Chapters are written by experts, covering the latest findings and new research being conducted about each phylum. Edwin L. Cooper is a Distinguished Professor in the Laboratory of Comparative Immunology, Department of Neurobiology at UCLA’s David Geffen School of Medicine.
