World Congress of Malacology Antwerp ... - Unitas Malacologica
World Congress of Malacology Antwerp ... - Unitas Malacologica World Congress of Malacology Antwerp ... - Unitas Malacologica
Ultrastructural and cytochemical study of the oesophagus of Bulla striata (Opisthobranchia) Lobo-da-Cunha, Alexandre 1 ; Calado, Gonçalo 2 1. Instituto de Ciências Biomédicas de Abel Salazar, Oporto University and CIIMAR, Largo Abel Salazar 2, 4099-003 Porto, Portugal, Email: alcunha@icbas.up.pt 2. Universidade Lusófona de Humanidades e Tecnologias, Lisbon, Portugal and IMAR, FCT/UNL, 2829-516 Caparica, Portugal, Email: bagoncas@gmail.com Specimens of Bulla striata (Cephalaspidea) were collected in Ria de Alvor an estuary in the South coast of Portugal. In order to extend the current knowledge about the digestive tube in opisthobranchs, their oesophaguses were fixed with a mixture of glutaraldehyde and paraformaldehyde, post-fixed with OsO4, dehydrated in ethanol and embedded in Epon. Semithin sections (2µm) were used for light microscopy studies and ultrathin sections for observations by transmission electron microscopy (TEM). In the most anterior region, including the dorsal oesophageal pouch, the columnar epithelium is ciliated and most cells present apical protrusions with a homogeneous content devoided of organelles. These protrusions are released into the lumen, an activity that seems to be particularly intense in the epithelium of the oesophageal pouch. Posteriorly to the oesophageal pouch, the epithelium is covered with microvilli embedded in a thick coat of granulo-fibrilar material, but apocrine secretion was not observed. In all the epithelium, the cytoplasm above the nucleus contains electron-dense lysosomes and residual bodies, in general, showing a reduced arylsulphatase activity. These cells can accumulate high amounts of glycogen in the cytoplasm above and below the nucleus, but lipid droplets are scarce. Subepithelial gland cells are very abundant in the wall of the oesophagus, except in the oesophageal pouch. The gland cells have a long neck that crosses the epithelium reaching the lumen, but the main cell body is embedded in the connective tissue below the epithelium. Large electron-lucent secretory vesicles containing a web of filaments and many Golgi stacks fill most of their cytoplasm, but mitochondria and lysosomes are also present. These cells can be stained by PAS reaction in semithin sections and their secretory vesicles contain acid mucopolysaccharides that were detected by colloidal iron particles in TEM. The outer layer of the oesophageal wall is formed by muscle cells. Effects of Cd 2+ on the calcium metabolism and shell mineralization of bivalve Anodonta cygnea Lopes-Lima, Manuel 1 ; Hinzmann, Mariana 2 ; Faubel, David 3 ; Machado, Jorge 1 1. Instituto de Ciências Biomédicas Abel Salazar Largo Prof. Abel Salazar, 2, 4099- 003 Porto, Portugal, Email: lopeslima@aquicultura.com; jmachado@icbas.up.pt 2. Centro Interdisciplinar de Investigação Marinha e Ambiental,Rua dos Bragas, 289 - 4050-123 Porto Portugal, Email: mhinzmann@bio.ua.pt 3. Department of Environmental Chemistry and Ecotoxicology, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany, Email: david.faubel@stmail.uni-bayreuth.de The survival of freshwater mussels is easily affected by cadmium pollution due to the fact that it accumulates in bivalves displacing the calcium ion in its transport and regulation mechanisms. A first study with freshwater bivalves Anodonta cygnea under enriched Ca 2+ (2 mM) water during different periods (three, four and eighteen days), showed a calcium content with a significant (P
different compartments were analyzed on Ca 2+ and Cd 2+ composition as well as other ions relevant to the osmoregulation. Concerning the second study experimental groups it was shown high significant (P
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different compartments were analyzed on Ca 2+ and Cd 2+ composition as well as other ions relevant to<br />
the osmoregulation. Concerning the second study experimental groups it was shown high significant<br />
(P
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