An ultrastructural study of excretory system development in the cercariae of Prosorhynchoides gracilescens (Rudolphi, 1819) and Prosorhynchus squamatus Odhner, 1905 (Digenea, Bucephalidae)

The ultrastructure of the developing excretory system of Prosorhynchoides gracilescens and Prosorhynchus squamatus cercariae is described. The development pattern was similar in both species. In early embryos the two main collecting tubes were composed of a layer of cells which were wrapped around t...

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Bibliographic Details
Published in:Parasitology 2004-08, Vol.129 (2), p.165-179
Main Authors: PODVYAZNAYA, I. M., GALAKTIONOV, K. V., IRWIN, S. W. B.
Format: Article
Language:English
Subjects:
Animals
Bladder
Bucephalidae
cercaria
development
Digenea
Digestive System - ultrastructure
Embryos
Epithelium
Excretory system
Microscopy
Microscopy, Electron
Mollusca - parasitology
Parasitology
Pores
Prosorhynchoides gracilescens
Prosorhynchus squamatus
Studies
Systems development
Tegument
Trematoda - anatomy & histology
Trematoda - growth & development
Trematoda - ultrastructure
Tubes
Ultrastructure
Zoology
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Description
Summary:The ultrastructure of the developing excretory system of Prosorhynchoides gracilescens and Prosorhynchus squamatus cercariae is described. The development pattern was similar in both species. In early embryos the two main collecting tubes were composed of a layer of cells which were wrapped around the lumen. Later, the tubes fused and the excretory epithelium of the fusion zone and that of the lateral caudal ducts became a syncytium. The collecting tubes in the cercarial body retained their cellular organization. As the tails grew, additional excretory pores were formed in the tail stem where thickened portions of the caudal duct epithelium contacted the surface tegument. Following this, the distal portions of the lateral caudal ducts lost contact with the primary excretory pores and progressively degenerated. Excretory atrium development started with differentiation of secretory active cytons peripheral to the fusion zone. These cells gave rise to cytoplasmic extensions that penetrated the fusion zone wall to eventually form a continuous cytoplasmic layer. This layer eventually replaced some of the fusion zone excretory epithelium and became the lining of the excretory atrium. The anterior end of the fusion zone differentiated into an excretory bladder and a short posterior portion gave rise to the caudal vesicle.
ISSN:0031-1820
1469-8161
DOI:10.1017/S0031182004005487