Ultrastructural observation on the transformation of the spermatozoon in spermatogenesis of Taeniid cestodes.
OBJECTIVE
To study the transformation of taeniid spermatozoon during spermatogenesis on the ultrastructure level.


METHODS
Transmission electronmicroscopy.


RESULTS
This paper was the second part of the ultrastructural observations on the spermatogenesis in Taeniid cestodes: The transformation of the spermatozoon. The 64-spermatid-plasmodium was generated from the secondary meiosis of the 32 rose-like secondary spermatocytes. The transformation of the spermatozoon was a complex process. Firstly, both the cytoplasm and nucleus of the spermatid elongated while the cytoplasm increased and connected to the cytoplasmic mass (cytophore). Secondly, the chromatins of nucleus polymerized to a thread-bundle-like structure. Finally, it detached from the cytoplasm mass and became a mature spermatozoon. The mature spermatozoon was a thread-like structure, about 16.2-18.6 microns in length and 0.35-0.45 micron in diameter. There were two structurally distinct parts: the part with the nucleus was the head and the part without the nucleus was the tail. The head measured about 5-6 microns in length, 1/3 of the total body length and contained an elongated nucleus which twined around the axoneme without mitochondria. The tail was about 11.2-16.6 microns in length. Throughout the core of the tail was an axoneme with typical "9 + 1" structure. The anterior of the tail, just behind the head, were some mitochondria, about 1.6-1.7 microns in total length which twined around the axoneme. The posterior of the tail contained only an axoneme. In cross-section of the spermatozoon, about 46 microtubules were beneath the plasma membrane.


CONCLUSIONS
The transformation of the spermatozoon is a very complex process.
Tian
X
X
Department of Parasitology, North China Coal Medical College, Tangshan 063000.
Yuan
L
L
Huo
X
X
Han
X
X
Li
Y
Y
Xu
M
M
Lu
M
M
Dai
J
J
Dong
L
L
D000818:Animals; D008297:Male; D008854:Microscopy, Electron; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*; D013621:Taenia / Q000145:classification / Q000648:ultrastructure*