• Applied Microscopy
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• v.34 no.3
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• pp.159-170
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• 2004

Spermiogenesis in the Korean squirrel, Tamias sibiricus, was investigated by transmission electron microscopy. Spermiogenesis was divided into Golgi, cap, acrosome, maturation and spermiation phases based on the characteristics of acrosomal changes and nuclear shape. Beside, the Golgi, cap and acrosomal steps were subdivided into three phases of early, middle and late phase respectively, the maturation step was divided into two phases of early and late phase, and spermiation step has only one phase. Thus, the spermiognesis of T. sibiricus was divided into a total of twelve phases. In Golgi phase (steps 1-3), a well developed Golgi complex was located close to the vesicles, the acrosomal vesicle fixd to a recess of nuclear membrane at step 3. During cap phase (steps 4-6), the acrosomal vesicle spred over the nuclear surface to cover a third of the nucleus, and the acrosomal granule was not yet flattened. At acrosomal phase (steps 7-9), the nucleus and acrosome were elongated but nucleoplasm was not condensed. During maturation phase (steps 10-11), the nucleoplasm was more condensed, and the mitochondria completely arranged the center of axoneme. The spatulate-sperm head was completely formed at spermiation phase (step 12).

• Applied Microscopy
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• v.37 no.3
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• pp.185-198
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• 2007

Spermiogenesis in Japanese white-toothed shrew. Crocidura dsinezumi was investigated by transmission electron microscope. Spermiogenesis was divided into 12 phases 14 steps, based on the morphological features of the nucleus and change of organelles in cytoplasm. The nucleus of spermatids in Golgi (step $1{\sim}2$) phase were spherical; however, they were changed into oval in the cap (step $3{\sim}6$) phase. Flagellum appeared in the middle of acrosomal phase; on the other hand, slender and long spermatid head was formed in maturation phase. The head of spermatids faced the lumen in step 1 to step 6 (from Golgi to cap phase), but, in step 7 to step 14 (from acrosomal to spermiation phase), it turned its head to the basal lamina of the seminiferous epithelium. The nucleus and acrosome were elongated maximally in step 10. The condensation of chromatin started in late acrosomal (step 10) phase, and it was completely finished and homogenized in the middle of maturation (step 12) phase. Multivesicular body appeared near the acrosomal vacuole during the middle cap (step 5) phase, and a large number of them were observed near the Golgi apparatus in the late cap (step 6) phase. Considering all the results, the spermiogenesis might be useful information to analyse the differentiation of spermatogenic fells.

• The Korean Journal of Malacology
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• v.26 no.4
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• pp.311-316
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• 2010

Spermatid differentiations during spermiogenesis and mature sperm ultrastructure in male Crassostrea nipponica were investigated by transmission electron microscope observations. The morphology of the spermatozoon of this species has a primitive type and is similar to those of other bivalves. Mature spermatozoa consist of broad, cap-shaped acrosomal vesicle and an axial rod in subacrosomal materials on an oval nucleus showing deeply invaginated anteriorly, two triplet substructure centrioles surrounded by four spherical mitochondria, and satelite fibres, which appear near the distal centriole. The acrosomal vesicle of spermatozoa of C. nipponica resemble to those of other investigated ostreids. Especially, two transverse bands (stripes) appear at the anterior region of the acrosomal vesicle, unlikely 2-3 transverse bands (stripes) in C. gigas. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm morphology in the resolution of taxonomic relationships within the Ostreidea. The sperm is approximately $48-50{\mu}m$ in length including an oval sperm nucleus (about $1.0{\mu}m$ in length and $1.41{\mu}m$ in width), an acrosome (about $0.48{\mu}m$ in length and 0.30 in width) and tail flagellum ($46-48{\mu}m$). The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9 + 2 structure. These morphological charateristics of acrosomal vesicle belong to the family Ostreidae in the subclass Pteriomorphia.

• Development and Reproduction
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• v.1 no.2
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• pp.133-139
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• 1997

To study the function and structure of Golgi apparatus in the spermiogenesis of long-fingered bat (Miniopterus schreibersi fuliginosus), the testis obtained from adult bat was treated with the prolonged osmification or fixed with ferrocyanide reduced osmium. golgi apparatus was oval shape in early Golgi phase, and was composed of cortex and medullar enclosing acrosome in mid Golgi phase. The vesicles of crescent shape Golgi apparatus were closed or fused with small or large vesicles at the periphery of acrosome. Golgi apparatus moved behing the acrosome face in cap phase, but the Golgi apparatus was still active. According to this, Golgi apparatus appears to be involved in the formation of acrosome and sperm tail. Transfer of materials from Golgi to acrosme seems to be carried out not only by fusion of large vesicles with acrosomal vesicles but also by detachment of coated vesicle from various cisternae of Golgi fusing with acrosomal vesicle.

• The Korean Journal of Malacology
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• v.27 no.2
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• pp.149-157
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• 2011

Some characteristics of the formations of acrosomal vesicles during the late stage of spermatids during spermiogenesis and taxonomical charateristics of sperm morphology in male two species (Saxidomus purpurata and Meretrix petechialis) in the family Veneridae were investigated by electron microscope observations. In two species, the morphologies of the spermatozoa have the primitive type and are similar to those of other bivalves in that it contains a short midpiece with five mitochondria surrounding the centrioles. The morphologies of the sperm nuclear types of S. purpurata and M. petechialis in Veneridae have the curved cylindrical and cylinderical type, respectively. And the acrosome shapes of two species are the same cap-shape type. In particular, the axial filament is not found in the lumen of the acrosome of two species, however, subacrosomal material are observed in the subacrosomal spaces between the anterior nuclear fossa and the acrosomal vesicle of two species. The spermatozoon of S. purpurata is approximately 46-$52{\mu}m$ in length, including a curved sperm nucleus (about $3.75{\mu}m$ in length), a long acrosome (about $0.40{\mu}m$ in length),and a tail flagellum (about 45-$47{\mu}m$ long). And the spermatozoon of M. petechialis is approximately 47-$50{\mu}m$ in length including a slightly curved sperm nucleus (about $1.50{\mu}m$ in length), an acrosome (about $0.56{\mu}m$ in length) and tail flagellum (44-$48{\mu}m$ in length). In two species, the axoneme of the sperm tail flagellum of each species consists of nine pairs of microtubules at the periphery and a pair of cental doublets at the center. Therefore, the axoneme of the sperm tail flagellum shows a 9 + 2 structure. In particular, taxonomically important some charateristics of sperm morphologies of two species in the family Veneridae are acrosomal morphology of the sperm, The axial filament is not found in the acrosome as seen in a few species of the family Veneridae in the subclass Heterodonta. The acrosomal vesicle is composed of right, left basal rings and the apex part of the acrosomal vesicle. In particular, right and left basal rings show electron opaque part (region), while the apex part of the acrosomal vesicle shows electron lucent part (region). These charateristics belong to the subclass Heterodonta, unlikely 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 acrosomal structures. The number of mitochondria in the midpiece of the sperm of S. purpurata and M. petechialis in Veneridae are five. However, the number of mitochondria in the midpiece of the sperm in most species of Veneridae in the subclass Heterodonta are four. Therefore, the number of mitochondria of the sperm midpiece of two species are exceptionally 5, and it is only exceptional case in the species in Veneridae in the subclass Heterodonta. Except these cases, the number of mitochondria in the sperm midpiece in all families in the subclass Heterodontaare are 4, and now widely used in taxonomic analyses.

• Development and Reproduction
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• v.18 no.3
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• pp.179-186
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• 2014

Characteristics of the developmental stages of spermatids during spermiogenesis and phylogenetic classicfication of the species using sperm ultrastructures in male Crassostrea ariakensis were investigated by transmission electron microscope observations. The morphology of the spermatozoon of this species has a primitive type and is similar to those of Ostreidae. Ultrastructures of mature sperms are composed of broad, modified cap-shaped acrosomal vesicle and an axial rod in subacrosomal materials on an oval nucleus, four spherical mitochondria in the sperm midpiece, and satellite fibres which appear near the distal centriole. The axoneme of the sperm tail shows a 9+2 structure. Accordingly, the ultrastructural characteristics of mature sperm of C. ariakensis resemble to those of other investigated ostreids in Ostreidae in the subclass Pteriomorphia. In this study, particularly, two transverse bands (stripes) appear at the anterior region of the acrosomal vesicle of this species, unlike two or three transverse bands (stripes) in C. gigas. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm ultrastructures and morphologies in the resolution of taxonomic relationships within the Ostreidae in the subclass Pteriomorphia. These spermatozoa, which contain several ultrastructures such as acrosomal vesicle, an axial rod in the sperm head part and four mitochondria and satellite fibres in the sperm midpiece, belong to the family Ostreidae in the subclass Pteriomorphia.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.55-65
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• 2011

Some characteristics of germ cell differntiations during spermiogenesis and mature sperm ultrastructure in male Phacosoma japonicus were investigated by transmission electron microscope observations. The morphology of the spermatozoon of this species has a primitive type and is similar to those of other species in the subclass Heterodonta. Morphologies of the sperm nucleus and the acrosome of this species are the cylindrical type and cap shape, respectively. The spermatozoon is approximately 45-50 ${\mu}m$ in length, including a long curved sperm nucleus (about $3.70{\mu}m$ long with 45 $^{\circ}$ of the angle of the nucleus, an acrosome (about $0.55{\mu}m$ in length), and tail flagellum (about 42-$47{\mu}m$)The axoneme of the sperm tail shows a 9+2 structure. As some characteristics of the acrosomal vesicle structures, the basal and lateral parts of basal rings show electron opaque part (region), while the anterior apex part of the acrosomal vesicle shows electron lucent part (region). These characteristics of the acrosomal vesicle were found in the family Veneridae and other several families in the subclass Heterodonta. These common characteristics of the acrosomal vesicle in the subclass Heterodonta can be used for phylogenetic and systematic analysis as a taxonomic key or a significant tool. The number of mitochondria in the sperm midpiece of this species are four, as one of common characteristics appear in most species in the family Veneridae and other families in the subclass Heterodonta. However, exceptionally, only three species in Veneridae of the subclass Heterodonta contain 5 mitochondria. The number of mitochondria in the sperm midpiece can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

• Korean Journal of Animal Reproduction
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• v.3 no.2
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• pp.24-31
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• 1979

The maturation changes in morphology were studied with the spermatozoa collected from the testis and three successive parts of the epididymis in Korean native Cattle. Acrosomal granules were observed in the testis. Avoiding the cap and acrosome phases, the tail base and the striated column of the neck were formed in spermatides. The volume of the acrosome was decreased during transit from the testis to the epididymis. The cell membranes were also separated from the acrosome or damage during the spermatozoan passage through successive parts of the reproductive tract. Cytoplasmic droplets were observed in the spermatozoa collected from various parts of the reproductive tract.

• Applied Microscopy
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• v.39 no.2
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• pp.89-99
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• 2009

To investigate the morphological characteristics of spermatozoa of the grey red-blacked vole (Clethrionomys rufocanus) belongings to the subfamily Cricetinae, subgenus Clethrionomys were examined by scanning and transmission electron microscopes. The sperm head of C. rufocanus was an ax or hatchet in shape with a curved single dorsal hook. The total length of C. regulus sperm was 95.8 ${\mu}m$. The length of sperm head was 7.8 ${\mu}m$, and the tail (88.0 ${\mu}m$) consisted of four major segments: the neck (1.0 ${\mu}m$), middle piece (22.0 ${\mu}m$), and principal piece plus end piece (65.0 ${\mu}m$), respectively. The segmented columns were about 10~12 in number. The number of gyres of mitochondria ranged from about 170 to 178. The post-nuclear cap occupied about a half of nucleus. The equatorial segment is located between the post-nuclear cap segment and acrosomal cap on the nuclear surface. Nos. 1, 5 and 6 of the outer dense fibers were larger than the others. A fibrous sheath and longitudinal column of the principal piece were in evidence, but the fibrous sheath was not seen at the end piece. In conclusion, the morphological structures of sperm head and tail may be useful information to patterning of sperm evolution and classifying of species.

• Applied Microscopy
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• v.41 no.2
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• pp.99-107
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• 2011

Light microscope, and scanning and transmission electron microscopy were used to investigate the fine structure of sperm of the Korea squirrel, Tamias sibiricus. The sperm head of T. sibiricus was paddle in shape. The total length of T. sibiricus sperm was 67.8 ${\mu}m$. The length of sperm head was 7.8 ${\mu}m$, and the tail (60.0 ${\mu}m$) was consisted of four major segments: the neck (1.0 ${\mu}m$), middle (8.0 ${\mu}m$), principal (48.5 ${\mu}m$) and end piece (2.5 ${\mu}m$), respectively. Especially, the length of the middle piece is short, and end piece was very shorter than those of other rodents. The post-nuclear cap was occupied about a fifth of nucleus. The equatorial segment is located between the post-nuclear cap segment and acrosomal cap on the nuclear surface. Nine segmented columns were surrounded by the mitochondria, and numbers of gyres of mitochondria were 26. One segmented column was consisted ten to twelve knobs, and each of segmented column in the neck region connected with the nine outer dense fiber in the middle piece. Numerous satellite-like fibers were scattered around the segmented columns. Nos. 1, 5 and 6 of the outer dense fibers in the middle piece were larger than the others. A fibrous sheath and longitudinal column of the principal piece were in evidence, but the fibrous sheath and longitudinal column was not seen at the end piece. In conclusion, the structural features of sperm head and tail may be useful information to patterns of sperm evolution and classification of species.