Structure and functions of the digestive tract of Alvinella pompejana , a hydrothermal vent polychaete
1990; NRC Research Press; Volume: 68; Issue: 4 Linguagem: Inglês
10.1139/z90-105
ISSN1480-3283
AutoresC. Saulnier-Michel, Françoise Gaill, A. Hily, Patrick Albéric, M. A. Cosson-Mannevy,
Tópico(s)Parasite Biology and Host Interactions
ResumoThe different parts of the digestive tract of Alvinella pompejana are described. The buccal apparatus presents a ventral pharyngeal organ, which is thought to be protrusible, and a dorsal anterior oesophageal gland. Unusual racks are observed in this part, a fact that confirms the deposit feeding behaviour of the worm which has been hypothetized. The serous cells of the oesophageal gland may be the origin of the proteolytic activity detected in the lumen. Intracellular enzymatic activities are detected in the stomach cells. These cells are characterized by numerous iron concretions and polyphagosomes. Comparative elemental analysis of these concretions lead us to think that this digestive segment is a homeostatic organ. The intestine is composed of an absorbant epithelium including enterocytic cells, myocytes, and cells containing zymogenic granules. As much as 90% of ingested protein matter occurs in a water-soluble state (half of it free amino acids, principally glycine) immediately on passing through the anterior part of the gut lumen. In the hindgut, solid faeces are mostly composed of elemental sulfur and are glycine depleted, making them good candidates to form the bulk of the suspended particles found in the waters closely surrounding the worm colonies. The whole gut content contains a high concentration of elemental sulfur. The digestive process of the worm is discussed.
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