• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.252-257
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• 2019

We investigated the microstructure and morphological characteristics of microplastics added to rinse off cosmetics by scanning electron microscope. The size of the microplastic was in a wide range of sizes, from $250{\mu}m$ to 1.5mm in diameter. The small microplastics were in the shape of elongated particles and the large microplastics were cuboidal. Most cubic microplastics were observed in the form of squares or rectangles. The surface of the cubic microplastic was smoothly observed without protruding portions, but irregularly many gaps were formed. The gap between openings was measured from about $5{\mu}m$ to $20{\mu}m$. It has not been confirmed that these gaps are formed from the surface of the microplastic to the inside there of.

• 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.

• Korean Journal of Microbiology
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• v.23 no.4
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• pp.265-270
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• 1985

Overall procedure of cell fusion between Brevibacterium flavum and Corynebacterium glutamicum was morphologically observed by transmission electron microscopy. Protoplasts formed by treatment of cells with penicillin G and lysozyme in order were released through the pores generated on a certain region of cell walls to be spherical form. When two different protoplasts were met, cell wall and membrane in the contact zone was disappeared and followed by the mutual exchange of cytoplasmic and/or chromosomal materials. Cell xall regeneration speed of the protoplasts fused was slower than that of the non-fused, whereas the size of the former was confirmed as bigger than that of the latter.

• Korean Journal of Poultry Science
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• v.28 no.3
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• pp.267-274
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• 2001

The pineal gland of the bird occupies a key position in the phylogenetic evolution of this organ. Therefore, the purpose of this study was to investigate the developmental changes of the pineal gland during post-hatching period in Korean pheasant. The pheasants were sacrificed at 1-day-, 1-month-, 2-month-, and 6-month-old after hatching. The morphological characteristics of a pineal glands were determined in all pheasants using light microscope, and transmission electron microscope. Connective tissue originated from the capsule divided the pineal parenchyma into incomplete lobules. The parenchyma was consisted of pinealocytes and supportive cells. These parenchymal cells were arranged in the forms of solid lobules as well as incomplete follicles. At the follicular lumen, membraneous lamellar complexes and blob -like structures were present. Pinealocyte, a predominent cell type, had euchromatic nucleus, and showed the segmental organization. The bulbous apical portion had scanty free ribosomes and occasional cilia associated with basal bodies. The constricted neck, transitional portion from apical to pericarya had junctional complexes with adjacent supportive cells, and had microtubules. Cell body contained abundant mitochondria, well-developed Golgi complex, rough endoplasmic reticulum (RER) and free ribosomes. Basal processes extended from the base of the cell soma toward the basal lamina and contained 60∼90 nm dense cored vesicles. Supportive cells, another major type of the parenchyma, were characterized by the dense and elongated nucleus, and contained moderate number of mitochondria, RER, developed Golgi complex, free ribosomes and a few dense bodies in the perinuclear cytoplasm. Slender processes of supportive cells interposed between the pinealocytes and often bordered the basal region of the parenchyma. These results indicate that the pinealocytes of the pheasant are not rudimentary photoreceptor cells, and appear to have secretory function. Further studies will be required to confirm the morphological characteristics of pineal gland in adult pheasant during breeding and nonbreeding season.

• Journal of Ginseng Research
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• v.26 no.4
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• pp.213-218
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• 2002

Crystalline calcium oxalate occur throughout near)y all plants species in five major forms; styloids, druses, raphids, prisms and sands. These crystals are known to be distributed in specific tissue such as cortex, xylem, phloem, cambium and epidermis. This research was undertaken to identify the occurrence, type, location and ultrastructure of druse crystals in Panax ginseng. In situ visualization, conventional light microscopy, histochemistry and scanning electron microscopy were applied for these purposes. Druse crystals in ginseng were identified as calcium oxalate by silver nitraterubeanic acid histochemistry. Calcium oxalate crystals are observed in nearly all plant organs such as leaf, petiole, peduncle, stem, rhizome, tap root and lateral root except fine root. Most frequent observation of crystals in the leaf and rhizomes were noticed. Three different types of calcium of oxalate druse crystals were identified by scanning electron microscopy.

• Tuberculosis and Respiratory Diseases
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• v.53 no.4
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• pp.457-462
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• 2002

Karagener's syndrome is an inherited condition characterized by triad of chronic paranasal sinusitis, situs inversus, and bronchiectasis, Since 1976, Afzelius found a lack of dynein arm in immotile spermatozoa by electron microscopy, numerous recent studies have focused on the ultrastructural defect in the cilia and reported that the variety type of ultrastructural defect in immotile cilia syndrome. We report a female patient who had the Katagener's triad with rare multiple ultrastructural defect of cilia in one patient. The electron microscopic examination showed partial dynein arm defect, loss of radial spoke, microtubular transposition, and giant cilia.

• The Korean Journal of Zoology
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• v.26 no.1
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• pp.29-40
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• 1983

The differences in the electron microscopic fine structures of the wing imaginal discs of the vestigial (vg), wing mutant and wild type of Drosophila melanogaster were investigated. The materials used in this study were collected at ten hours intervals from the late third instar larvae of the both stocks. The fine structural changes during differentiation were as follows: 1. In wild type lipid droplets were coalesced and converted to glycogen, while no changes were observed in the mutatn vestigial. 2. Degeneration of the cells by phagocytosis were observed not only from the mutatn vestigial, but from the wild type. However, degenerative feature of the wild type was poor. 3. Dented structures of tracheole showed little differences between wild type and the mutant vestigial. But the tracheole diameter of the wild type became wider in the course of differentiation, while the mutant vestigial narrow. Although mutant vestigial develops normally during early embryogenesis, the late third instar larvae shows defficiency in gluconeogenesis, converting fatty acid to glycogen. This, together with the predominant cell degeneration by phagocytosis and poorly developed tracheole, seems to effect on the expression of the vestigial phenotype.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.25-33
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• 1983

With electron microscope, author studied on the pulp structure of human primary tooth in shedding stage. Non-carious human primary molar teeth were selected for this study. Using standard methods, specimens were sectioned and examined by light and electron microscope, The results were as follows; 1. In coronal pulp, odontoblasts were replaced by multinucleated odontoclasts, which contained a large number of mitochondria of varying shape and vacuoles in cytoplasm. Where odontoclasts were in contact with tooth surface, the characteristic ruffled border and clear zone were observed. 2. Fibrous tissue with plentiful collagen fibers and fibroblasts was observed adjacent to the dentin in the pulp. Fibroblast contained a number of mitochondria and well-developed rough-surfaced endoplasmic reticulum. 3. Inflammatory cells were observed in the pulp and active fibroblasts could be seen between inflammatory cells. In many cases, cervical epithelium proliferated toward absorbed area. 4. Inflammatory cells consisted of a number of lymphocytes, polymorphonuclear leukocytes, plasma cells and macrophages. Macrophage containing lysosomes in digestive state or phagocyting PMN could be seen. 5. In the primary molar of delayed root resorption, odontoblast layer, zone of Weil and cell-rich zone could be seen at roof of pulp chamber and odontoblast in this area cont과ained some lipid droplets.

• Applied Microscopy
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• v.13 no.1
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• pp.49-61
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• 1983

Protoplast releasing mechanisms from Trichoderma koningii, fine structures of the released protoplsts, and their regeneration mode were studied by scanning and transmission electron microscopy. Two types of protoplast releasing mechanisms were observed. In one mechanism, cytoplasm emerged through a cell wall pore developed by cell lytic enzymes and formed a spherical protoplast. In the other mechanism, as the cell wall became progressively thinner, the inner cytoplasm partially rounded to form nonspherical bodies which became spherical protoplasts after being released into the enzyme solution. But, these two types of protoplast releasing mechanisms did not seem to be. mutually exclusive but could occur on the same mycelium simultaneously. And it appeared that cytoplasm which did not become a protoplast by the first mechanism could from a protoplast by the second mechanism. The preparations contained two types of protoplasts, released from different sites of the mycelia. Those released from younger mycelia had dense cytoplasm and small vesicles. Those released from the older mycelia had less dense cytoplasm and larger vacuoles. In the case of regeneration, before producing normal mycelia, most of the protoplasts assumed aberrant tube and yeast-like-forms. Normal mycelia were produced at the end of the yeastlike-forms and sometimes in the middle of the aberrant tube.

• The Korean Journal of Zoology
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• v.19 no.4
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• pp.143-154
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• 1976

The hemocytes of Drosophila melanogaster were observed with electron microscope, and five types of the cells were identified; prohemocyte, plasmatocyte, granular cell, crystal cell and oenocytoid, accounting for about 5%, 35%, 45%, 10%, 5% respectively of total cell numbers. Prohemocytes are characterized by a low concentration of intracellular organelles. Plasmatocytes are spindle or oval in shape and have relatively plenty of organelles and lysosomes. Granullar cells are the most polymorphic. They have numerous pseudopod-like projections and contain various granules and inclusions. In this cell type, intracellular organelles are fully developed. Crystal cells are characterized by numerous crystals composed of fine granules arranged regularly. Oenocytoids are the largest one among all cell types and contain relatively developed organelles.