• 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.

• Proceedings of the Malacological Society of Korea Conference
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• 1999.11a
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• pp.17-17
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• 1999

• Applied Microscopy
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• v.16 no.2
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• pp.35-48
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• 1986

Ultrastructures of the cutaneous xanthophores and formation of pigment granules in the goldfish, Carassius auratus L., are studied with electron microscope. The cutaneous xanthophores are observed only in dermis and pigment granules of these pigment cells are pterinosomes and carotenoid vesicles. By the differentiated level, pterinosomes are subdivided into 3 types; while type I pterinosomes have clear limiting membranes and contain some amorphous fine fibrous structures, type II pterinosomes have thick and densely aggregated fibrous materials. Type III pterinosomes have concentric lamellar structures in the granules. Pigment granules of the xanthophores are originated from the Golgi complexes and pinocytotic vesicles of plasma membrane as well as rER-rich cells among the chromatophores are presumed to be associated with the accumulation of pigment materials.

• Applied Microscopy
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• v.30 no.2
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• pp.205-212
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• 2000

Present study was performed to observe the surface ultrastructures of Stictadora furcatum (Trematoda: Heterophyidae). Adult worms were recovered from the cat experimentally infected with metacercariae, and were prepared for scanning electron microscopy. The body was leaf-like and ventrally concave. The oral sucker armed with prominent tegumental spines on the inner surface, and it's lips were obscure. Sensory papillae (type I) in single or grouped forms symmetrically arranged around the oral sucker. The ventrogenital opening retained protruding gonotyl spines and sperms discharged from the genital pore . The body surface was covered with scale-like multipointed tegumental spines. The density and digitated point of spines were gradually decreased toward the posterior end of the body. The digitated points of spines on the anterior portion were 9-12, on the middle were 7-8 and 5-6, and on the posterior were 2-3 and peg-like. Although the tegumental ultrastructure of S. fuscatum was generally similar to those of other heterophyid flukes , the oral sucker with tegumental spines on the inner surface and without obvious lips, and the ventrogenital opening with protruding gonotyl spines were suggested to be the characteristic features.

• Applied Microscopy
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• v.19 no.2
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• pp.17-26
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• 1989

The cells of Campylobacter jejuni treated with physical or chemical disinfection agents were comparatively examined by scanning and transmission electron microscopies for their morphological features and internal ultrastructures. The normal cells of C. jejuni, showed typical spiral rod shapes. The ribosomes, nucleoids, and other cellular constituents were observed to be distributed evenly throughout the cytoplasm. The cells treated with heat or UV-light were changed to spherical or irregular shapes and their cell envelopes were destroyed to form ghost cells by liberating their cytoplasmic components. The cells treated with chlorine or monochloramine were also changed into irregular round shapes. The chlorinated cells showed very rough surface structures with many blob-like protrusions, while the surface of the monochloramine-treated cells appeared to be relatively smooth.

• Applied Microscopy
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• v.50
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• pp.13.1-13.7
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• 2020

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of Ancistrus cirrhosus belong to Loricariidae using light and electron microscopes. The fertilized eggs formed a mass on the spawning place and were yellowish, spherical, non-transparent, demersal, adhesive, and a narrow perivitelline space. But, the adhesiveness of fertilized eggs was disappeared after spawning excluding contact parts. The micropyle with funnel shape was surrounded by 15-19 furrow lines of egg envelope in a spoke-like pattern. The outer surface of egg envelope has smooth side and inner surface of egg envelope was rough with grooves. Also, the total thickness of the fertilized egg envelope was about 32.58 ± 0.85 ㎛ (n = 20), and the fertilized egg envelope consisted of three layers, an outer adhesive electron-dense layer, a middle layer with low electron density and an inner electron-dense layer with grooves in counter structure from other most teleost. Collectively, these morphological characteristics and adhesive property of fertilized egg, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

• Proceedings of the Zoological Society Korea Conference
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• 2000.04a
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• pp.73.2-73
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• 2000

No Abstract, See Full Text

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.183-192
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• 1993

A transmission electron microscopic study was performed to observe the ultrastructures of the male germinal cells and spermatozoa of Fibricola seoulensis. Spermatogonia were found in the periphery of the testis and characterized by large nuclei and comparatively little cytoplasms. Spermatocytes contained an oval to spherical nucleus. Their nuclear volume was little larger in comparative to that of cytoplasm, and the chromatin was comparatively little. The early spermatids were characterized by a great amount of cytoplasm, and numerous mitochondria encircled the nucleus. In a more advanced spermatids the electron-dense strands of chromatin appeared in the nucleus, and a pair of rootlet of the axoneme and a microtubule-organizing center (MTOC) were observed near the nucleus. The sectioned spermatozoa were found in the testis and the seminal vesicle. Their cross sectional views were divided into 6 types when they were distinguished on the basis of the morphology and components. The spermatozoa of F. seoulensis showed two flagella of 9+1 type axoneme.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.211-218
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• 2014

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 $48-51{\mu}m$ in length including a curved cylinderical sperm nucleus (about $4.18{\mu}m$ long), an acrosome (about $0.52{\mu}m$ in length) and tail flagellum ($42-45{\mu}m$ 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 $80^{\circ}$), as seen in some species of Veneridae (range from $0^{\circ}$ to $80^{\circ}$). 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.

• Applied Microscopy
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• v.47 no.2
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• pp.70-74
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• 2017

In the case of genus Nothobranchius, Nothobranchiidae, the morphology of fertilized eggs and ultrastructures of fertilized egg envelopes have been reported in only two fishes. Therefore it is hard for sure to these morphological characteristics show genus specificity because of lower research samples. So, we studied the morphology of fertilized egg, and compared the ultrastructures of outer surface, micropyle, and section of fertilized egg envelopes under the light and electron microscopes from the other two species, Nothobranchius foerschi and Nothobranchius rachovii, Nothobranchiidae to find out whether these structures have the species specificity or not. Both fertilized eggs were spherical, demersal and adhesive, and have a large oil droplet. The adhesive whip-like structures were distributed on the outer surface of egg envelope, and a micropyle located on the animal pole. The fertilized egg envelope consisted of two distinct layers: an outer electron-dense layer with adhesive structures and an inner lamellae layer in both species. The external shapes of fertilized egg and ultrastuctures of outer surface, micropyle, and section of fertilized egg envelope have same structure including results before. Our data indicate that these morphological characteristics of fertilized egg and fertilized egg envelope show genus Nothobranchius specificity.