MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
Ultrastructure of the digestive gland of the marine gastropod Adelomelon beckii (Broderip 1836)
Autor/es:
ARRIGHETTI, F.
Revista:
Unitas Malacologica Newsletter
Editorial:
Unitas Malacologica
Referencias:
Año: 2009 vol. 28 p. 4 - 4
ISSN:
1011-2375
Resumen:
Adelomelon beckii (Volutidae: Zidoninae) is an endemic neogastropod to the South Atlantic Ocean, which is distributed from Espiritu Santo, Brazil to Tierra del Fuego, Argentina. It is the biggest carnivore specie, often exceeding 40 cm in shell length, that inhabits sandy bottoms between 30 and 70 m water depth. This specie is selected for this study because is a common and conspicuous element of this high polluted area and because of its economical importance for the artisanal fishery of Argentina. The digestive gland of A. beckii is formed by a complex of numerous tubules bounded together by connective tissue and muscle fibers. The tubules are made up of two cell types: digestive and basophilic cells. Digestive cells exhibit different phases: immature, absorption, digestion and excretion, each with distinct appearance, being the digestive phase the most frequently encountered. Digestive cells are connected by desmosomes and septate junctions. At the base of the microvilli, numerous pinocytotic vesicles were observed. The most conspicuous feature of these cells was the presence of numerous membrane-bound vacuoles, which for descriptive purposes were divided in three categories. Vacuoles type Va, Vb and type Vc. Peroxisomes and lisosomes were also observed in digestive cells. Basophilic cells are pyramidal and occur in small groups. No morphological changes were observed during the different phases. The cytoplasm contains a vesicular appearance due to the presence of a highly developed endoplasmatic reticulum. The cisternae are concentrically orientated and dominate most part of the cytoplasm. Lipid droplets, mitochondria and autophagic vesicles are also observed. In conclusion the main functions of digestive cells are endocytosis and posterior intracellular digestion while basophilic cells are in charge of protein synthesis for intracellular digestion.(Volutidae: Zidoninae) is an endemic neogastropod to the South Atlantic Ocean, which is distributed from Espiritu Santo, Brazil to Tierra del Fuego, Argentina. It is the biggest carnivore specie, often exceeding 40 cm in shell length, that inhabits sandy bottoms between 30 and 70 m water depth. This specie is selected for this study because is a common and conspicuous element of this high polluted area and because of its economical importance for the artisanal fishery of Argentina. The digestive gland of A. beckii is formed by a complex of numerous tubules bounded together by connective tissue and muscle fibers. The tubules are made up of two cell types: digestive and basophilic cells. Digestive cells exhibit different phases: immature, absorption, digestion and excretion, each with distinct appearance, being the digestive phase the most frequently encountered. Digestive cells are connected by desmosomes and septate junctions. At the base of the microvilli, numerous pinocytotic vesicles were observed. The most conspicuous feature of these cells was the presence of numerous membrane-bound vacuoles, which for descriptive purposes were divided in three categories. Vacuoles type Va, Vb and type Vc. Peroxisomes and lisosomes were also observed in digestive cells. Basophilic cells are pyramidal and occur in small groups. No morphological changes were observed during the different phases. The cytoplasm contains a vesicular appearance due to the presence of a highly developed endoplasmatic reticulum. The cisternae are concentrically orientated and dominate most part of the cytoplasm. Lipid droplets, mitochondria and autophagic vesicles are also observed. In conclusion the main functions of digestive cells are endocytosis and posterior intracellular digestion while basophilic cells are in charge of protein synthesis for intracellular digestion.