Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"planarians"”.
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Mechanisms of tissue-specific regeneration in planarians
How animals establish and maintain the sizes of myriad tissues and organs in tight proportion to one another is a fundamental question of developmental biology. Planarian flatworms regenerate from diverse injuries, in each case precisely restoring body parts to their appropriate proportions. …
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Pattern formation and essential responses for regeneration in planarians
… for regeneration are poorly understood. Planarians can robustly regenerate all tissues after injury, involving stem cells, patterning cues and a set of cellular and molecular responses collectively called the "missing tissue" or "regenerative" response. The missing tissue response has …
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How, when, and where: fate selection in regenerative planarians
… after injury. Cell-type production in planarians is regulated by the expression of fate-specific transcriptions factors (FSTFs) in dividing cells called neoblasts. However, it remains unclear whether all ~150 fate choices are made in neoblasts, or whether additional mechanisms for …
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Organizer regeneration and patterning of stem cell lineages in planarians
Planarians are freshwater flatworms capable of whole-body regeneration. Like development, regeneration requires the establishment of tissue patterns and the specification of appropriate cell types. However, regeneration has the additional challenges of performing these tasks in the absence of …
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teashirt is required for head-versus-tail regeneration polarity in planarians
Regeneration requires that the identities of new cells are properly specified to replace missing tissues. The Wnt signaling pathway serves a central role in specifying posterior cell fates during planarian regeneration. We identified a gene encoding a homolog of the Teashirt family of zinc finger …
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Molecular mechanisms of regeneration initiation and dorsal-ventral patterning in planarians
… mechanisms that govern regenerative processes. Planarians have emerged in recent years as a powerful model for studying regeneration and are capable of whole-body regeneration following a limitless variety of injuries. Two major questions in planarian regeneration have been: 1) how are the …
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ACME and SPLiT-seq: Quantitative and evolutionary single-cell transcriptomics in planarians
… I present the single-cell atlases of multiple planarians (Schmidtea mediterranea, Schmidtea polychroa, Dugesia japonica, Girardia tigrina and Polycelis nigra), and compare the differences between sexual and asexual strains and life-history stages of the same species. This data includes over …
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An insulin-like peptide regulates size and adult stem cells in planarians
Animal growth depends on nutritional intake during development. In many animals, nutritional status is uncoupled from moderation of adult stature after adult size is achieved. However, some long-lived animals continue to regulate adult size and fertility in a nutrition-dependent manner. For …
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Genetic regulation of neuronal stem cell differentiation: a single-cell sequencing study in planarians
Cellular specialisation is incredibly prominent in the nervous system, where even in a single brain region, individual neurons may differ deeply in their molecular, anatomical, and functional features. Platyhelminthes like Schmidtea mediterranea continuously turn over all their tissues, including …
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Functional Analysis of Genes Involved in Regulating Stem Cell Maintenance and Differentiation in the Freshwater Planarian Schmidtea Mediterranea
Freshwater planarians have been a classic model for regeneration studies for more than 250 years. The great regenerative abilities of planarians rely on neoblasts, adult stem cells maintained throughout the animal's life. This thesis reports an analysis of genes that regulate stem cell maintenance …
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From coarse fate choice to precise pattern: post-mitotic progenitor targeting
Planarians possess remarkable regenerative abilities, driven by pluripotent stem cells called neoblasts. While neoblasts are known to give rise to progenitor cells that form various tissues, whether and the extent to which these progenitors migrate across the animal remains unclear. Irradiation …
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Comprehensive single-cell transcriptional profiling of the regenerative planarian Schmidtea mediterranea
… cell types and cell states in a complete animal. Planarians are freshwater flatworms renowned for their capacity for whole-body regeneration. They possess a complex body plan with multiple distinct tissues. They also possess a population of dividing cells, called neoblasts, which contain …
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MECHANISMS DRIVING PLANARIAN STEM CELLS TO EVADE RADIATION-INDUCED APOPTOSIS
… two independent ways in which stem cells in planarians, flatworms that are inherently resistant to cancer, can survive radiation. Planarians have a large population of stem cells that rapidly proliferate and are essential for regeneration. These cells are also ordinarily radio-sensitive, and …
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Characterization of the hermaphroditic reproductive system and sexual development in the planarian Schmidtea mediterranea
… the difference between asexual and sexual planarians, we performed microarray analyses to identify genes that were expressed differentially in sexual and asexual planarians. We also used immuno- and lectin-staining to visualize components of the reproductive system. These complementary …
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The Limits of Longevity
… including some highly regenerative species of planarians and Hydra that reproduce through asexual fission. However, all demographic studies have limits on observation times and sample sizes, so it is unknown if these failures were because of an actual absence of aging or these inherent study …
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Regeneration and maintenance of the planarian nervous system
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 …
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Epidermis and Re-epithelialization in <i>Schmidtea mediterranea</i>
… wound healing capacity is described in detail in planarians. Our work introduces live imaging methodology, which allows following epidermal cells and their response to tissue damage or tissue loss for extended time (hours) and in high resolution. Using our methods, we followed planarian cells live …
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Biosignal Recording with Integrated Circuits
… in small worms and for future application on planarians. Two improved electrode configurations are presented: a design with strip lines for longitudinal recordings and a 3D-printed concentric matrix electrode array for multidirectional recordings. The functionality of the non-invasive …
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Mechanisms Controlling Hatching of Winter Eggs of the Flatworm Mesostoma Ehrenbergii
… the class Turbellaria are free- living. Although planarians have frequently been used as models of the turbellarian type, Ruebush (1940) and other authors advocate the use of Mesostoma ehrenbergii for such studies. Individuals of this species are very cosmopolitan, and have been recorded from a …
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The instructive roles of muscle cells in planarian regeneration
… information to correctly place new tissue. Planarians are flatworms with remarkable capacity to regenerate after nearly any injury and to indefinitely maintain tissue homeostasis. Dividing cells, neoblasts, are the source of all new tissue, whereas positional information is hypothesized to …
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