Ultrastructure of the spermatozoon of the anoplocephalid cestode Gallegoides arfaai (Mobedi and Ghadirian, 1977) Tenora and Mas-Coma, 1978, an intestinal parasite of the wood mouse (Apodemus sylvaticus Linnaeus, 1758) (original) (raw)
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Parasitology Research, 1998
The mature Paranoplocephala omphalodes spermatozoon is filiform, tapered at both ends and lacks mitochondria. Its anterior extremity exhibits an apical cone of electron-dense material measuring about 900 nm in length and 200 nm in width, and two crested-like bodies. The cortical microtubules follow a 25-35 degrees helicoidal path along their whole length, except at the posterior extremity where they become parallel to the spermatozoon axis. They are arranged in a single or two fields which may cover each other partially. The axoneme, of the 9 + "1" pattern of the Trepaxonemata, lacks a peri-axonemal sheath and does not reach the extremity of the spermatozoon. The nucleus is a compact and irregular cord coiled in a spiral around the axoneme. Moreover, we report for the first time a nucleus in the spermatozoon of a Cyclophyllidea species which reaches beyond the axonemal posterior extremity. The cytoplasm, depending on the level where the section is cut, is slightly electron dense or electron lucent and contains numerous small electron-dense granules in regions III-V. In the posterior spermatozoon extremity, granular material is replaced by a terminal and compact electron-dense material.
Parasitology research, 2011
Spermiogenesis and ultrastructure of the spermatozoon of two bothriocephalidean cestodes, Oncodiscus sauridae from the lizardfish Saurida nebulosa Valenciennes, 1850 and Senga sp. from the eel Mastacembelus armatus (Lacepède, 1800), have been studied using transmission electron microscopy. Spermiogenesis included the formation of a zone of differentiation, where two centrioles associated with the striated rootlets occur. An intercentriolar body composed of one thick central electron-dense plate and two thinner plates on each side appears between two centrioles. Two flagella of unequal length grow and undergo a vertical rotation and proximodistal fusion with the median cytoplasmic process. Subsequently, the nucleus penetrates into the median cytoplasmic extension. The electron-dense material in the early stages of spermiogenesis is characteristic for the apical region of the differentiation zone. This electron-dense material is typical for basal tapeworms, e.g., Bothriocephalidea, Caryophyllidea, Diphyllobothriidea, and Spathebothriidea. The mature spermatozoon of O. sauridae and Senga sp. is filiform and possesses two axonemes of the 9 + “1” trepaxonematan pattern, a nucleus, cortical microtubules, and electron-dense granules. The anterior part of the gamete contains a single electron-dense crested body. The most interesting character found is the presence of a ring of cortical microtubules encircling the axoneme in the anterior part of the spermatozoon. This feature has been detected only for species of the order Bothriocephalidea and may represent a synapomorphy of these tapeworms. A classical pattern for spermatological characters (spermiogenesis of type I with dense material in early stages and sperm of type II with a characteristic ring of cortical microtubules in the anterior part) in Bothriocephalidea is discussed.
Helminthologia, 2020
Summary The mature spermatozoon of Khawia armeniaca, a monozoic caryophyllidean parasite of templar fish Capoeta capoeta sevangi (De Filippi, 1865) from the Lake Sevan, Armenia, has been studied using transmission electron microscopy and cytochemical technique of Thiéry (1967) for the first time. The mature spermatozoon of K. armeniaca consists of a single axoneme with the 9+‘1’ trepaxonematan structure, cortical microtubules and nucleus which are situated parallel to the longitudinal axis of the spermatozoon, and a moderately electrondense cytoplasm with glycogen particles. The cortical microtubules are arranged in one continuous semicircle beneath the plasma membrane in Region II and anterior part of Region III of the mature spermatozoon. The two opposite rows of cortical microtubules are observed in the remaining nuclear and at the beginning of the postnuclear part (Regions III, IV) of the male gamete The number of cortical microtubules is remarkably variable in the spermatozoa o...