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Ultrastructure of interlamellar Henneguya exilis in the channel catfish
Abstract:
Ultrastructural aspects of interlamellar Henneguya exilis infections in channel catfish are reported. The plasmodium wall of this form differs from that of other species in that it is composed of two outer unit membranes which give rise to a zone of numerous pinocytic canals. Single-membraned canals appeared to be a stable feature of the wall while double-membraned canals are interpreted as those actively carrying out pinocytosis. Evidence suggests that host cellular cytoplasm as well as interstitial material is taken in by plasmodia. Plasmodium wall integrity, aggregation of parasite ectoplasmic components, numbers of pinocytic canals, and number of mitochondria proximal to the wall vary among different plasmodium profiles and may be related to plasmodium maturity. The parasite causes extensive hyperplasia of basal cells, which in turn replaces most other cell types found in noninfected gill filaments. Cytoarchitectural differences between basal cells of noninfected filaments and basal cells adjacent to plasmodia include significantly shorter microfilament bundles in the latter.
Insights
Henneguya exilis infections in channel catfish feature unique plasmodium walls with pinocytic canals for nutrient uptake. These infections cause significant gill tissue changes, impacting fish health.
Area of Science:
- Ichthyology
- Parasitology
- Cell Biology
Background:
- Henneguya exilis is a myxosporean parasite affecting channel catfish.
- Understanding parasite-host interactions at the ultrastructural level is crucial for disease management.
Purpose of the Study:
- To investigate the ultrastructural characteristics of Henneguya exilis plasmodia in channel catfish.
- To elucidate the mechanism of nutrient uptake and host cell alterations during infection.
Main Methods:
- Transmission electron microscopy was used to examine infected gill tissues.
- Comparative analysis of plasmodial structures and host cell cytoarchitecture.
Main Results:
- Henneguya exilis plasmodia possess a unique wall with two outer unit membranes and numerous pinocytic canals.
- Evidence suggests active pinocytosis of host cytoplasm and interstitial material.
- Infection leads to basal cell hyperplasia and altered microfilament bundles in host cells.
Conclusions:
- The unique plasmodium wall facilitates nutrient acquisition in Henneguya exilis.
- Parasite-induced cytoarchitectural changes in host cells highlight significant host-parasite interactions.