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