Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord

Detalhes bibliográficos
Autor(a) principal: Azevedo, Tomás Augusto Barreiros Pais de, 1986-
Data de Publicação: 2009
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10451/1420
Resumo: Tese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2009, Universidade de Lisboa, Faculdade de Ciências
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spelling Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochordEmbriologia animalSomitogéneseTeses de mestradoTese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2009, Universidade de Lisboa, Faculdade de CiênciasIn this thesis, we sought to analyze the dynamics of amniote and anamniote embryo axis elongation and the possible role of the notochord. For that, we chose the chick and zebrafish as representative model organisms of each group. We found that in the zebrafish embryo, elongation has two different phases during the stages analysed, from shield to 15 somite stage. The first phase is characterized by a constant (i.e., linear) growth rate which is faster than that observed during the second phase. The first phase occurs simultaneously with the epiboly movements of the basltoderm and yolk-syncytial layer (YSL). In chick embryos, we also find a constant (linear) growth phase which spans from stage HH4-11 (Hamburger & Hamilton 1951), a period during which the chick embryo forms structures homolog to those formed by zebrafish embryos during the first (linear) growth phase. Furthermore, in chick embryos, we found that the cranial portion elongates at a slower rate than that of two other portions of the embryo: the segmented and pre-somitic portions of the embryo, which contain all tissues adjacent to the segmented and pre-somitic mesoderm, respectively. Using micromanipulation techniques we show that elongation in the chick is independent of the primitive streak and a direct connection of Hensen's node to the extra-embryonic tissues. This contrasts with zebrafish embryo development where it has been well established that axis extension only occurs if there is an intact connection between the embryo and the YSL. We propose that the structures that could contribute to axis extension are: the notochord, the neural tube and the paraxial mesoderm. Again, using micro-manipulation techniques, we show that none of three different portions of the notochord (cranial, segmented and pre-somitic ) are essential for embryo axis elongation. However, preliminary experiments suggest that the presence of the whole notochord might contribute to the process of embryo axis extension. This work shows that the notochord is not the main driver of early embryo axis extension in amniotes, a hypothesis that had been advanced in the literature often but had not yet been formally tested. Clearly, the forces that shape the early vertebrate embryo into its typical elongated shape come from tissues inside the embryo itself, other than the notochord. In amniotes, these forces have evolved in order to allow the embryo to extend autonomously, without the additional force produced by expanding extra-embryonic tissues, as still seen in most anamniotes (e.g., fish and amphibians)Resumo alargado em português disponível no documentoMartins, Gabriel G.Thorsteinsdóttir, Sólveig, 1962-Repositório da Universidade de LisboaAzevedo, Tomás Augusto Barreiros Pais de, 1986-2010-07-27T08:58:11Z20092009-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfapplication/pdftext/xmlhttp://hdl.handle.net/10451/1420enghttp://catalogo.ul.pt/F/?func=item-global&doc_library=ULB01&type=03&doc_number=000569395info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-11-08T15:40:55Zoai:repositorio.ul.pt:10451/1420Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:28:03.990380Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
title Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
spellingShingle Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
Azevedo, Tomás Augusto Barreiros Pais de, 1986-
Embriologia animal
Somitogénese
Teses de mestrado
title_short Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
title_full Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
title_fullStr Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
title_full_unstemmed Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
title_sort Dynamics of embryo axis elongation in amniotes vs. anamniotes:the role of the notochord
author Azevedo, Tomás Augusto Barreiros Pais de, 1986-
author_facet Azevedo, Tomás Augusto Barreiros Pais de, 1986-
author_role author
dc.contributor.none.fl_str_mv Martins, Gabriel G.
Thorsteinsdóttir, Sólveig, 1962-
Repositório da Universidade de Lisboa
dc.contributor.author.fl_str_mv Azevedo, Tomás Augusto Barreiros Pais de, 1986-
dc.subject.por.fl_str_mv Embriologia animal
Somitogénese
Teses de mestrado
topic Embriologia animal
Somitogénese
Teses de mestrado
description Tese de mestrado, Biologia (Biologia Evolutiva e do Desenvolvimento), 2009, Universidade de Lisboa, Faculdade de Ciências
publishDate 2009
dc.date.none.fl_str_mv 2009
2009-01-01T00:00:00Z
2010-07-27T08:58:11Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10451/1420
url http://hdl.handle.net/10451/1420
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv http://catalogo.ul.pt/F/?func=item-global&doc_library=ULB01&type=03&doc_number=000569395
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
text/xml
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
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instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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