Electron Microscope Studies on Spermiogenesis in Various Animal Species

Yasuzumi, G.

doi:10.1016/s0074-7696(08)61357-1

Cited by 57 publications

(19 citation statements)

References 320 publications

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“…26D; Boisson and Mattei, 196513;Butler and Gabri, 1984;Clark, 1967;Courtens and Depeiges, 1985;da CruzLandim and da Cruz-Hofling, 1977;Hess et al, 1991;Yasuzumi, 1974;Yasuzumi and Yasuda, 1968). The perforatorium in reptiles has been shown to contain actin (Baccetti, 1979).…”

Section: Reptiliamentioning

confidence: 99%

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Spermatogenesis in nonmammalian vertebrates

Pudney

1995

Microscopy Res & Technique

178

120

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Spermatogenesis appears to be a fairly conserved process throughout the vertebrate series. Thus, spermatogonia develop into spermatocytes that undergo meiosis to produce spermatids which enter spermiogenesis where they undergo a morphological transformation into spermatozoa. There is, however, variation amongst the vertebrates in how germ cell development and maturation is accomplished. This difference can be broadly divided into two distinct patterns, one present in anamniotes (fish, amphibia) and the other in amniotes (reptiles, birds, mammals). For anamniotes, spermatogenesis occurs in spermatocysts (cysts) which for most species develop within seminiferous lobules. Cysts are produced when a Sertoli cell becomes associated with a primary spermatogonium. Mitotic divisions of the primary spermatogonium produce a cohort of secondary spermatogonia that are enclosed by the Sertoli cell which forms the wall of the cyst. With spermatogenic progression a clone of isogeneic spermatozoa is produced which are released, by rupture of the cyst, into the lumen of the seminiferous lobule. Following spermiation, the Sertoli cell degenerates. For anamniotes, therefore, there is no permanent germinal epithelium since spermatocysts have to be replaced during successive breeding seasons. By contrast, spermatogenesis in amniotes does not occur in cysts but in seminiferous tubules that possess a permanent population of Sertoli cells and spermatogonia which act as a germ cell reservoir for succeeding bouts of spermatogenic activity. There is, in general, a greater variation in the organization of the testis and pattern of spermatogenesis in the anamniotes compared to amniotes. This is primarily due to the fact there is more reproductive diversity in anamniotes ranging from a relatively unspecialized condition where gametes are simply released into the aqueous environment to highly specialized strategies involving internal fertilization. These differences are obviously reflected in the mode of spermatogenesis and this is particularly true of the stage of spermiogenesis where the morphology of the species-specific spermatozoon is determined. Moreover, unlike amniotes, many anamniotes display a spermatogenic wave manifest, depending upon the species, either at the level of the cyst or seminiferous lobule. This variation in the organization of the testis makes certain anamniotes perfect models for investigating germ cell development and maturation. For instance, the presence of a spermatogenic wave provides an opportunity to manually isolate discrete germ cell stages for analysis of specific Sertoli/germ cell interactions. Furthermore, for many anamniotes, germ cells mature in association with a morphologically poorly developed Sertoli cell. This seeming independence of Sertoli cell regulation allows the in vitro culture of isolated germ cells of some species of anamniotes through several developmental stages. Thus, due either to the anatomical organization of the testis, or structural simplicity of the germinal units, nonmammalian vert...

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Section: Reptiliamentioning

confidence: 99%

“…With further condensation of the chromatin, the fibers become thicker and tightly packed to produce the fully condensed nuclei of mature spermatozoa. It is assumed that chromatin condensation re- sults from dehydration of nucleoprotein and nucleoplasm elimination (Yasuzumi, 1974).…”

Section: Reptiliamentioning

confidence: 99%

Spermatogenesis in nonmammalian vertebrates

Pudney

1995

Microscopy Res & Technique

178

120

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“…fibrillar (Yasuzumi & Sugioka, 1966;Yasuzumi, 1974). During spermiogenesis, nuclear elongation takes place in the absence of a microtubular manchette.…”

Section: Methodsmentioning

confidence: 99%

“…The third type is represented by the helicoidal sperm of the Passeriformes (Furieri, 1961(Furieri, , 1962(Furieri, , 1963Yasuzumi el nl., 1970;Humphreys, 1972;Yasuzumi, 1974 …”

Section: Methodsmentioning

confidence: 99%

Comparative observations on spermiogenesis

Saita

Tripepi

Longo

1982

Bolletino di zoologia

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To estend the study on bird spermiogenesis we have observed by electron microscopy the mature testis of the cuculiform Crofopbaga ani.During nucleus elongation the chromatin condenses in dense granules and the nucleoplasm is reducing. The Golgi apparatus starts the developing of the acrosomal vesicle. The elongating nucleus drives the acrosomal vesicle against the cell membrane. At the opposite side the flagellum arises from the distal centriole and comes out from the cell at a very early stage. \Vhile the cytoplasm is reducing, the mitochondria arrange themselves around the distal centriole and around the fore part of the asoneme.The elongating spermatid does not have a microtubular manchette or a microtubular bundle, as seen in other birds. It is entirely surrounded by a Sertoli cell, which shows many microtubules. scattered in the cytoplasm. These microtubules are arranged parallel to the axis of elongating spermatids. Near the Sertoli cell membrane, surrounding the acrosome, is electron-dense material.The perforatorium, present in the sperm of Galliformes and Anseriformes, is absent. A subacrosornal space, found in Columbiformes sperm, is also absent.The morphogenetic factors influencing the head shape of this sperm seem to be peculiar and probably related to the microtubular apparatus of the Sertoli cell.

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“…Therefore, the processes of spermatogenesis of bivalves was similar to those in the species in bivalves (Sakker, 1984;Bernard and Hodgson, 1985;Chung, 2006;Chung et al, 2007, Kim et al, 2010. Yasuzumi (1974) reported that the nuclei of spermatids can be classified into three morphological types according to the concentration morphology and degree of chromatins in the nuclei of spermatids: (1) granular, (2) fibrous, and (3) layer types. In general, in case of bivalves, it was a granular type in the early stage of chromatin concentrations, however, as the concentration of chromatins progresses, it was changed to be the fibrous type.…”

Section: Spermatogenesismentioning

confidence: 99%

Spermiogenesis and Taxonomical Values of Sperm Ultrastructures in Male Mercenaria stimpsoni (Heterodonta: Veneridae)

Kim¹,

Son²,

Kim³

et al. 2014

The Korean Journal of Malacology

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Spermatid differentiations during spermiogenesis and sperm ultrastructures in male Mercenaria stimpsoni were investigated by transmission electron microscopic observations. In the early stage of the spermatid during spermiogenesis, a few granules and a proacrosomal granule, which is formed by the Golgi complex, become a proacrosomal vesicle. Consequently, it becomes an acrosome by way of the process of acrosome formation. The morphologies of the sperm nucleus type and the acrosome of this species have a curved cylindrical type and cap shape, respectively. The spermatozoon is approximately 48-51 μm in length including a curved cylinderical sperm nucleus (about 4.18 μm long), an acrosome (about 0.52 μm in length) and tail flagellum (42-45 μm long). As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part (region), while the apex part of the acrosome shows electron lucent part (region). These charateristics of the sperm belong to the family Veneridae in the subclass Heterodonta, unlike a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part (region). Therefore, it is easy to distinguish the families or the subclasses by the acrosome structures. Exceptionally, In particular, a cylinder-like nucleus of the sperm is curved (the angle of the nucleus is about 80°), as seen in some species of Veneridae (range from 0° to 80°). The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appeared in most species except for a few species in Veneridae in the subclass Heterodonta. Cross-sectioned axoneme of the sperm tail flagellum shows a 9+2 structure.

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Electron Microscope Studies on Spermiogenesis in Various Animal Species

Cited by 57 publications

References 320 publications

Spermatogenesis in nonmammalian vertebrates

Spermatogenesis in nonmammalian vertebrates

Comparative observations on spermiogenesis

Spermiogenesis and Taxonomical Values of Sperm Ultrastructures in Male Mercenaria stimpsoni (Heterodonta: Veneridae)

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