Long lengths of microtubules apparently break down very rapidly (100mum in under a second) during a hitherto undescribed feeding response. Microtubular axopodia elastically resist mild bending along their longitudinal axes. They yield non-elastically when more severe bending is applied; bends are formed at certain points along their longitudinal axes. A polarised repair process returns bent axopodia to their normal straight form. Bends under repair move out along axopodia towards their tips. Employing these bends as markers it has been shown that breakdown of microtubules takes place at the tips of tubules at the distal ends of axopodia when axopodial shortening is induced with colchicine. Evidence has been gained which suggests that microtubule growth and breakdown may be restricted to precisely localised areas within an organism. Apart from this crude control over the presence or absence of tubules in a certain position, it appeal's that the cell has provision for the re-deployment of prefabricated groups of microtubules. A study of tubule regrowth and of the formation of patterned aggregates of microtubules after experimental disassembly suggests that tubule initiation, orientation and pattern formation occur as temporally separate processes. Pattern formation does not appear to depend on a pre-existing pattern of nucleating sites based on a two-dimensional template.

Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-10-16T22:28:32Z No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_TaxonomiaEspeciesBrasileiras.pdf: 3169225 bytes, checksum: da29dbb8def2c457a9ab78aee2c118f7 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-10-25T16:31:56Z (GMT) No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_TaxonomiaEspeciesBrasileiras.pdf: 3169225 bytes, checksum: da29dbb8def2c457a9ab78aee2c118f7 (MD5) / Made available in DSpace on 2013-10-25T16:31:56Z (GMT). No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_TaxonomiaEspeciesBrasileiras.pdf: 3169225 bytes, checksum: da29dbb8def2c457a9ab78aee2c118f7 (MD5) Previous issue date: 2009 / Este trabalho se divide em dois capítulos: “Capítulo I - Sobre a identidade da espécie-tipo Actinopus tarsalis Perty, 1833 (Araneae, Mygalomorphae, Actinopodidae)” e “Capítulo II - Taxonomia das Espécies Brasileiras da Actinopus Perty, 1833 (Araneae, Mygalomorphae, Actinopodidae)”. Esse formato foi utilizado para acelerar o processo de publicação, necessário para validar as modificações taxonômicas propostas no trabalho. O primeiro capítulo é passível de submissão imediata e foi formatado segundo as normas da revista Iheringia (Anexo I). O segundo capítulo, também formatado de acordo com as normas da revista Iheringia (Anexo I), será submetido após sua complementação com o exame do material tipo do BMNH.