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 of various Khawia species. K. armeniaca exhibits the highest number of cortical microtubules in comparison with K. sinensis and K. rossittensis. Glycogen was detected in the cytoplasm of prenuclear (II), nuclear (III) and postnuclear (IV) regions with different ultrastructural organization of the mature spermatozoon of K. armeniaca. Variations of sperm ultrastructural characters within caryophyllideans and other cestodes are discussed.

• Keywords
• Caryophyllidea, Cestoda, Khawia armeniaca, spermatozoon, ultrastructure,
• Publication type
• Journal Article MeSH

The spermatozoon ultrastructure of the progenetic cestode Diplocotyle olrikii (Spathebothriidea) has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate (PA-TSC-SP) for glycogen. The spermatozoon is a filiform cell, tapered at both extremities. Its moderately electron-dense cytoplasm possesses two parallel axonemes of unequal lengths. New for the Cestoda is a finding of three types of the mature spermatozoa with respect to different axonemal structure. The first type has both axonemes with standard 9 + '1' trepaxonematan pattern. The second type is represented by a spermatozoon having one axoneme with 9 + '1' structure and the second one with 9 + 0 pattern. The third type includes the two axonemes with 9 + 0 pattern. Microtubule doublets of the 9 + 0 axonemes contain either inner dynein arms or no dynein arms. In addition to the two axonemes, all three types of the mature sperm cells contain parallel nucleus, parallel cortical microtubules, four electron-dense plaques/attachment zones, and glycogen. The anterior extremity of the gamete exhibits a centriole surrounded by a semiarc of up to five electron-dense tubular structures. The distal end of the first type spermatozoa exhibits two morphological variants, represented either by (i) nucleus or (ii) remnants of the disorganized axoneme. Distal extremity of the spermatozoa of the second and third types contains doublets and singlets of disorganized axoneme. The ultrastructural characters of the spermatozoon of progenetic D. olrikii support the basal position of the Spathebothriidea within the Eucestoda.

• Keywords
• Diplocotyle olrikii, Progenesis, Spathebothriidea, Spermatozoon, Ultrastructure,
• MeSH
• Axoneme ultrastructure   MeSH
• Cell Nucleus ultrastructure   MeSH
• Centrioles ultrastructure   MeSH
• Cestoda ultrastructure   MeSH
• Cytoplasm ultrastructure   MeSH
• Spermatogenesis physiology   MeSH
• Spermatozoa ultrastructure   MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Monozoic caryophyllidean cestodes, intestinal parasites of cyprinid fishes, represent a group of tapeworms with an unclear evolutionary history. As spermatology may provide phylogenetically important data, the spermiogenesis and ultrastructure of the mature spermatozoon have been investigated using an integrative approach combining transmission electron microscopy, cytochemistry and electron tomography in Khawia rossittensis (Szidat, 1937). The process of spermatid formation is accompanied by the presence of ultrastructural characters not described in traditional models of spermiogenesis, e.g., apical electron-dense material, the two striated roots situated unusually opposite each other, branching of typical striated roots, an intercentriolar body comprising five electron-dense and four electron-lucent layers, rotation of both free flagella and flagellar buds to the median cytoplasmic process at 90°, and a complete proximodistal fusion. The synchronous rotation of both flagellar buds and growing free flagella is an evolutionarily linked pattern favouring the hypothesis that the Caryophyllidea are not ancestral but are secondarily derived from polyzoic forms. Electron tomography analysis has revealed a unique feature of two helicoidal tubular structures in the central electron-dense core of the axoneme of mature spermatozoon. These data provide new insights into the architecture of the 9 + '1' axoneme, which is shared by male gametes of all trepaxonematan Platyhelminthes.

• MeSH
• Axoneme metabolism   MeSH
• Cestoda cytology   physiology   ultrastructure   MeSH
• Cyprinidae parasitology   MeSH
• Microscopy, Electron MeSH
• Spermatogenesis * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Spermiogenesis in progenetic and adult stages of Archigetes sieboldi Leuckart, 1878, a tapeworm parasitic in oligochaetes and fish respectively, has been examined using transmission electron microscopy and cytochemical staining for glycogen. General pattern of spermiogenesis is essentially like that of other caryophyllideans, i.e., apical dense material in the zone of differentiation in the early stages of spermiogenesis, rotation of free flagellum and a flagellar bud, and proximo-distal fusion. Interestingly, rotation of a free flagellum and flagellar bud to the median cytoplasmic process (MCP) has been observed unconventionally at > 90° only in progenetic stages. Typical striated roots associated with the centrioles occur rarely in A. sieboldi, and only in form of faint structures in advanced stages of spermiogenesis. In contrast to most caryophyllideans studied to date, penetration of the nucleus into the spermatid body has started before the fusion of the free flagellum with the MCP. This feature has been reported rarely but exclusively in the family Caryophyllaeidae. The unipartite mature spermatozoon of A. sieboldi is composed of one axoneme of the 9 + '1' trepaxonematan pattern with its centriole, parallel nucleus, and parallel cortical microtubules which are situated in a moderately electron-dense cytoplasm with glycogen particles. An unusual arrangement of cortical microtubules in the two parallel rows in region I of the spermatozoon is described here for the first time in the Caryophyllidea. Ultrastructural data on spermiogenesis and the spermatozoon in A. sieboldi from tubuficids and carp are compared and discussed with those in other caryophyllideans and/or Neodermata.

• Keywords
• Archigetes sieboldi, Caryophyllidea, Spermatozoon, Spermiogenesis, Ultrastructure,
• MeSH
• Axoneme ultrastructure   MeSH
• Staining and Labeling MeSH
• Cell Nucleus physiology   MeSH
• Cestoda ultrastructure   MeSH
• Cestode Infections veterinary   MeSH
• Flagella physiology   MeSH
• Glycogen analysis   MeSH
• Carps parasitology   MeSH
• Fish Diseases parasitology   MeSH
• Spermatids cytology   ultrastructure   MeSH
• Spermatogenesis physiology   MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Glycogen MeSH

Spermatozoon formation in Caryophyllaeides fennica (Schneider, 1902) is characterised by the following: (1) apical electron-dense material in the zone of differentiation, (2) typical striated roots situated unconventionally in opposite directions in early stages of spermiogenesis, (3) intercentriolar body composed of three electron-dense and two electron-lucent plates, (4) free flagellum and a flagellar bud that correspond to a greatly reduced flagellum and (5) rotation of free flagellum and a flagellar bud to the median cytoplasmic process at 90°. The development of two flagella of significantly unequal length clearly supports a derived form of spermiogenesis in the Caryophyllidea. New for cestodes is a finding of two additional striated roots situated opposite each other, in conjunction with both the flagellar bud and free flagellum. Mutual position of additional striated roots and typical striated roots is parallel in early stages and perpendicular in advanced stages of spermiogenesis. A complete proximodistal fusion gives rise to a mature spermatozoon consisting of one axoneme, parallel cortical microtubules, a nucleus and a moderately electron-dense cytoplasm with glycogen particles, detected by a technique of Thiéry (J Microsc 6:987-1018, 1967), in the principal regions (II, III, IV). Electron tomography analysis of the free flagellum and one axoneme of a mature spermatozoon of C. fennica provides clear evidence, for the first time, that two tubular structures are present in the central axonemal electron-dense core. Phylogenetically important aspects of spermiogenesis of the Caryophyllidea with one axoneme, and other cestodes with one or two axonemes, are briefly reviewed and discussed.

• Keywords
• Caryophyllaeides fennica, Caryophyllidea, Spermatozoon, Spermiogenesis, Ultrastructure,
• MeSH
• Axoneme ultrastructure   MeSH
• Cell Nucleus ultrastructure   MeSH
• Cestoda ultrastructure   MeSH
• Cestode Infections MeSH
• Flagella ultrastructure   MeSH
• Microtubules ultrastructure   MeSH
• Spermatogenesis physiology   MeSH
• Spermatozoa ultrastructure   MeSH
• Electron Microscope Tomography MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

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.

• MeSH
• Cestoda isolation & purification   physiology   ultrastructure   MeSH
• Chordata parasitology   MeSH
• Organelles ultrastructure   MeSH
• Spermatogenesis * MeSH
• Spermatozoa growth & development   ultrastructure   MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH