--- OA_place: publisher _id: '1406' abstract: - lang: eng text: Epithelial spreading is a critical part of various developmental and wound repair processes. Here we use zebrafish epiboly as a model system to study the cellular and molecular mechanisms underlying the spreading of epithelial sheets. During zebrafish epiboly the enveloping cell layer (EVL), a simple squamous epithelium, spreads over the embryo to eventually cover the entire yolk cell by the end of gastrulation. The EVL leading edge is anchored through tight junctions to the yolk syncytial layer (YSL), where directly adjacent to the EVL margin a contractile actomyosin ring is formed that is thought to drive EVL epiboly. The prevalent view in the field was that the contractile ring exerts a pulling force on the EVL margin, which pulls the EVL towards the vegetal pole. However, how this force is generated and how it affects EVL morphology still remains elusive. Moreover, the cellular mechanisms mediating the increase in EVL surface area, while maintaining tissue integrity and function are still unclear. Here we show that the YSL actomyosin ring pulls on the EVL margin by two distinct force-generating mechanisms. One mechanism is based on contraction of the ring around its circumference, as previously proposed. The second mechanism is based on actomyosin retrogade flows, generating force through resistance against the substrate. The latter can function at any epiboly stage even in situations where the contraction-based mechanism is unproductive. Additionally, we demonstrate that during epiboly the EVL is subjected to anisotropic tension, which guides the orientation of EVL cell division along the main axis (animal-vegetal) of tension. The influence of tension in cell division orientation involves cell elongation and requires myosin-2 activity for proper spindle alignment. Strikingly, we reveal that tension-oriented cell divisions release anisotropic tension within the EVL and that in the absence of such divisions, EVL cells undergo ectopic fusions. We conclude that forces applied to the EVL by the action of the YSL actomyosin ring generate a tension anisotropy in the EVL that orients cell divisions, which in turn limit tissue tension increase thereby facilitating tissue spreading. acknowledged_ssus: - _id: Bio - _id: PreCl alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Pedro full_name: Campinho, Pedro id: 3AFBBC42-F248-11E8-B48F-1D18A9856A87 last_name: Campinho orcid: 0000-0002-8526-5416 citation: ama: 'Campinho P. Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. 2013.' apa: 'Campinho, P. (2013). Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. Institute of Science and Technology Austria.' chicago: 'Campinho, Pedro. “Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading.” Institute of Science and Technology Austria, 2013.' ieee: 'P. Campinho, “Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading,” Institute of Science and Technology Austria, 2013.' ista: 'Campinho P. 2013. Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. Institute of Science and Technology Austria.' mla: 'Campinho, Pedro. Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading. Institute of Science and Technology Austria, 2013.' short: 'P. Campinho, Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading, Institute of Science and Technology Austria, 2013.' corr_author: '1' date_created: 2018-12-11T11:51:50Z date_published: 2013-10-01T00:00:00Z date_updated: 2026-07-29T10:00:09Z day: '01' degree_awarded: PhD department: - _id: CaHe - _id: GradSch doi_confirm: '1' language: - iso: eng month: '10' oa_version: None page: '123' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5801' status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: 'Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading' type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2013' ... --- OA_place: publisher _id: '2964' abstract: - lang: eng text: 'CA3 pyramidal neurons are important for memory formation and pattern completion in the hippocampal network. These neurons receive multiple excitatory inputs from numerous sources. Therefore, the rules of spatiotemporal integration of multiple synaptic inputs and propagation of action potentials are important to understand how CA3 neurons contribute to higher brain functions at cellular level. By using confocally targeted patch-clamp recording techniques, we investigated the biophysical properties of rat CA3 pyramidal neuron dendrites. We found two distinct dendritic domains critical for action potential initiation and propagation: In the proximal domain, action potentials initiated in the axon backpropagate actively with large amplitude and fast time course. In the distal domain, Na+-channel mediated dendritic spikes are efficiently evoked by local dendritic depolarization or waveforms mimicking synaptic events. These findings can be explained by a high Na+-to-K+ conductance density ratio of CA3 pyramidal neuron dendrites. The results challenge the prevailing view that proximal mossy fiber inputs activate CA3 pyramidal neurons more efficiently than distal perforant inputs by showing that the distal synapses trigger a different form of activity represented by dendritic spikes. The high probability of dendritic spike initiation in the distal area may enhance the computational power of CA3 pyramidal neurons in the hippocampal network. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Sooyun full_name: Kim, Sooyun id: 394AB1C8-F248-11E8-B48F-1D18A9856A87 last_name: Kim citation: ama: Kim S. Active properties of hippocampal CA3 pyramidal neuron dendrites. 2012. apa: Kim, S. (2012). Active properties of hippocampal CA3 pyramidal neuron dendrites. Institute of Science and Technology Austria. chicago: Kim, Sooyun. “Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites.” Institute of Science and Technology Austria, 2012. ieee: S. Kim, “Active properties of hippocampal CA3 pyramidal neuron dendrites,” Institute of Science and Technology Austria, 2012. ista: Kim S. 2012. Active properties of hippocampal CA3 pyramidal neuron dendrites. Institute of Science and Technology Austria. mla: Kim, Sooyun. Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites. Institute of Science and Technology Austria, 2012. short: S. Kim, Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites, Institute of Science and Technology Austria, 2012. corr_author: '1' date_created: 2018-12-11T12:00:35Z date_published: 2012-06-01T00:00:00Z date_updated: 2026-06-18T18:41:53Z day: '01' degree_awarded: PhD department: - _id: PeJo - _id: GradSch language: - iso: eng month: '06' oa_version: None page: '65' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '3755' related_material: record: - id: '3258' relation: part_of_dissertation status: public status: public supervisor: - first_name: Peter M full_name: Jonas, Peter M id: 353C1B58-F248-11E8-B48F-1D18A9856A87 last_name: Jonas orcid: 0000-0001-5001-4804 title: Active properties of hippocampal CA3 pyramidal neuron dendrites type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2012' ... --- OA_place: publisher _id: '3962' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Holger full_name: Pflicke, Holger id: CAA57A9A-5B61-11E9-B130-E0C1E1F2C83D last_name: Pflicke citation: ama: Pflicke H.   Dendritic cell migration across basement membranes in the skin. 2010. apa: Pflicke, H. (2010).   Dendritic cell migration across basement membranes in the skin. Institute of Science and Technology Austria. chicago: Pflicke, Holger. “  Dendritic Cell Migration across Basement Membranes in the Skin.” Institute of Science and Technology Austria, 2010. ieee: H. Pflicke, “  Dendritic cell migration across basement membranes in the skin,” Institute of Science and Technology Austria, 2010. ista: Pflicke H. 2010.   Dendritic cell migration across basement membranes in the skin. Institute of Science and Technology Austria. mla: Pflicke, Holger.   Dendritic Cell Migration across Basement Membranes in the Skin. Institute of Science and Technology Austria, 2010. short: H. Pflicke,   Dendritic Cell Migration across Basement Membranes in the Skin, Institute of Science and Technology Austria, 2010. corr_author: '1' date_created: 2018-12-11T12:06:08Z date_published: 2010-07-01T00:00:00Z date_updated: 2026-04-09T14:37:07Z day: '01' degree_awarded: PhD department: - _id: CaHe - _id: GradSch language: - iso: eng month: '07' oa_version: None publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '2165' status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: "\uFEFF\uFEFFDendritic cell migration across basement membranes in the skin" type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2010' ...