<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>The ultrastructure of the mature spermatozoon of the bothriocephalidean tapeworm Eubothrium rugosum, a parasite of the burbot, Lota lota (L.), was studied by transmission electron microscopy for the first time. In addition, spermatozoon ultrastructure of Eubothrium crassum has been re-assessed. New is the finding, that the mature spermatozoa of both species of the genus Eubothrium exhibit essentially the same general morphology. They are filiform cells tapering at both extremities, and they possess the two axonemes with 9+“1” pattern of Trepaxonemata, attachment zones, a nucleus, cortical microtubules (CMs), electron-dense granules, and a single crested body. Structural polymorphism of the CBs has been found within the two Eubothrium species for the first time. The anterior ring of electron-dense tubular structures surrounding a single axoneme marks the border between the two defined regions, region I and region II of the spermatozoon. This unique feature has only been observed in the Bothriocephalidea. The anuclear axoneme region II of Eubothrium spermatozoa fluently verges into a nuclear region III. The posterior part of the spermatozoon contains one-axoneme, few CMs and a posterior extremity of the nucleus that subsequently disappears. The posterior extremity of the male gametes of the genus Eubothrium exhibits elements of a disorganized axoneme which characterize also spermatozoa of the family Triaenophoridae. Discussed are interspecific similarities and differences between the spermatozoa of the two Eubothrium species as well as between these and other Eucestoda.</p></abstract>

The ultrastructure of the mature spermatozoon of the bothriocephalidean tapeworm Eubothrium rugosum, a parasite of the burbot, Lota lota (L.), was studied by transmission electron microscopy for the first time. In addition, spermatozoon ultrastructure of Eubothrium crassum has been re-assessed. New is the finding, that the mature spermatozoa of both species of the genus Eubothrium exhibit essentially the same general morphology. They are filiform cells tapering at both extremities, and they possess the two axonemes with 9+“1” pattern of Trepaxonemata, attachment zones, a nucleus, cortical microtubules (CMs), electron-dense granules, and a single crested body. Structural polymorphism of the CBs has been found within the two Eubothrium species for the first time. The anterior ring of electron-dense tubular structures surrounding a single axoneme marks the border between the two defined regions, region I and region II of the spermatozoon. This unique feature has only been observed in the Bothriocephalidea. The anuclear axoneme region II of Eubothrium spermatozoa fluently verges into a nuclear region III. The posterior part of the spermatozoon contains one-axoneme, few CMs and a posterior extremity of the nucleus that subsequently disappears. The posterior extremity of the male gametes of the genus Eubothrium exhibits elements of a disorganized axoneme which characterize also spermatozoa of the family Triaenophoridae. Discussed are interspecific similarities and differences between the spermatozoa of the two Eubothrium species as well as between these and other Eucestoda.

Ultrastructure of the mature spermatozoon of Eubothrium rugosum (Batsch, 1786) with a re-assessment of the spermatozoon ultrastructure of Eubothrium crassum (Bloch, 1779) (Cestoda: Bothriocephalidea)

Parasitological Institute, Slovak Academy of Sciences, Hlinkova 3, 04001, Košice, Slovak Republic

Laboratory of Aquatic Pathobiology, Department of Biology, OAbo Akademi University, Artillerigatan 6, FIN 20520, OAbo, Finland

Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 37005, České Budějovice, Czech Republic

Helminthologia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The ultrastructure of the mature spermatozoon of the bothriocephalidean tapeworm Eubothrium rugosum, a parasite of the burbot, Lota lota (L.), was studied by...

Ultrastructure of the mature spermatozoon of Eubothrium rugosum (Batsch, 1786) with a re-assessment of the spermatozoon ultrastructure of Eubothrium crassum (Bloch, 1779) (Cestoda: Bothriocephalidea)

Published Online: Dec 17, 2010

Page range: 257 - 263

DOI: https://doi.org/10.2478/s11687-010-0040-9

Keywords
ultrastructure, spermatozoon, Eubothrium, Bothriocephalidea, Cestoda

© 2010 Institute of Parasitology, SAS, Košice, Slovakia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Ultrastructure of the mature spermatozoon of Eubothrium rugosum (Batsch, 1786) with a re-assessment of the spermatozoon ultrastructure of Eubothrium crassum (Bloch, 1779) (Cestoda: Bothriocephalidea)

Published Online: Dec 17, 2010

Page range: 257 - 263

DOI: https://doi.org/10.2478/s11687-010-0040-9

Keywordsultrastructure, spermatozoon, Eubothrium, Bothriocephalidea, Cestoda

© 2010 Institute of Parasitology, SAS, Košice, Slovakia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
ultrastructure, spermatozoon, Eubothrium, Bothriocephalidea, Cestoda