• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.736-752
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• 1995

Fine structural changes of germ cell during the gametogenesis of Korean rockfish, Sebastes schlegeli sampled in west coast of Korea were investigated from September 1993 to August 1994. In a layer of microvilli of oocyte with active yolk duplication, many pinocytotic vesicles containing protein granules regarded as yolk precursors were observed. The multivesicular bodies were formed by gathered mitochondria. They are participated in formation of the primary yolk globules homogeneously filled with high dense particles and enclosed within a limiting membrane. The precursors of yolk globule appeared to be formed by modification of mitochondria and they developed into the primary yolk globules with participation of large and dense pinocytotic vesicles. Yolk globules in mature oocyte were consisted of three components: the crystalline type main body, the superficial layer with dense and fine granules, and the limiting membrane. Steroid hormone secreting cells were recognized in the interstitial cells of growing testis. Numerous endoplasmic reticula and large mitochondria with well developed tubular cristae appeared in their cytoplasms. The axoneme in the tail flagellum of spermatozoon consisted of nine pairs of microtubules at the periphery and one pair at the center, and they were covered with doublet microtubules.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.388-395
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• 2017

We investigated the toxicity of zinc and aluminum hot-dip galvanized sheet steel to abalone Haliotis discus hannai via changes in the gill and hepatopancreas using histological and transmission electron microscopy analysis. Experimental groups were composed of one control and four exposure conditions (direct or indirect exposure to zinc and aluminum hot-dip galvanized sheet steel). In the control group, aluminum exposure groups (direct and indirect), and indirect zinc exposure group, abalone mortality was not observed until the end of the experiment, and no histopathological changes were observed in the gill and hepatopancreas. However, the direct zinc exposure group exhibited 100% mortality. Ultrastructural analysis of the cytoplasm of ciliated and microvilli-bearing epithelial cells from gill filaments revealed electron-dense vesicles near the cell membrane and disruption of the nuclear membrane. We also observed swollen mitochondria and a loss of mitochondrial cristae. The hepatopancreas showed similar changes, and we detected highly electron-dense particles within the vesicles. These results suggest that abalone exposed directly to zinc hot-dip galvanized sheet steel experience acute toxicity, causing damage to cell organelles in the gill and hepatopancreas and, finally, inducing mortality.

• The Korean Journal of Zoology
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• v.31 no.4
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• pp.318-326
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• 1988

여포세포에서 합성된 난황단백질이 난모세포로 이동하는 동안에 난황체가 이 두 종류의 세포사이에 형성되었다가 결국은 난황막으로 전환한다. 단계7까지는 뚜렷하게 보이던 난모세포막과 여포세포막이 소멸되고 그 자리에 전자 밀도가 높은 난황체 물질이 산만하게 축적된다. 난황체는 단계9에서 막성 구조의 일종인 linkage bridge로 둘러싸여 단계11까지는 두께가 5∼7um가 되리 만큼 성숙한다. 단계13에서 난황체는 비로소 난황막으로 전환되는데, 이때 난황막의 두께는 겨우 1 U m에 지나지 않는다. 이러한 두깨의 감소는 난황체 물질이 다량 난모세포 쪽으로 이동한 것으로 생각 되었다. coated vesicle을 포함한 다양한 종류의 과립이 난황체 양쪽에서 관찰되었는데, 난모세포쪽에 출현한 과립은 난황체 물질이 난모세포로 이동되는 구조로 해석되었고 여포 세포쪽에서 관찰된 과립은 주로 난황체의 전자밀도와 동일한 점으로보아 여포세포에서 합성되어 난황체를 형성하는 물질로 이루어진 구조로 해석되었다. As yolk proteins are transported from !he follicle cells into oocvtes, vitelline body forms and changes into a vitelline membrane between the ko celt types during the vitellogenic period. Cell membranes of oocyte and follicle cells surrounding the oocyte disappear at stage 7 and high electron-dense substance of vitelline body simultaneously accumulates sporadically between the cell types. The vitelline body becomes surrounded by linkage bridge, a membranous structure, at stage 9 and greatly increases in thickness to be 5-7 U m thick at stage 11. At stage 13 the vitelline body becomes vitelline membrane, which is now only 1 U m thick, suggesting that much of the substance of the vitelline body has been transported into oocyte. Various types of vesicles including coated vesicles were observed at both sides of th vitelline body. The vesicles occurred at the side of oocyte were interpreted to be structures transported from the vitelline body into oocyte, whereas those found at the side of the follicle cells were thought to be structures made in the follicle cells and fused into the vitelline body.

• Applied Microscopy
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• v.30 no.2
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• pp.121-139
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• 2000

The morphogenesis of neuroblasts and plexiform layers, and establishment of its synapses were studied by electron microscopy in human embryos and fetuses ranging from 10 mm to 260 mm crown-rump length ($5\sim30$ weeks of gestational age). At 30 mm fetus the developing retina was composed of outer and inner neuroblastic layers . Cell division of outer neuroblast was occurred until 90 mm fetus. The transient layer of Chievitz was formed by 30 mm fetus, inner plexiform layer by 50 mm fetus, and outer plexiform layer by 150 mm fetus. The cytoplasm of differentiating ganglion cells contained ribosomes, rough endoplasmic reticula, Golgi complexes, microtubules and dense bodies. The processes of $M\ddot{u}ller$ cell penetrated between groups of ganglion cell axons, and formed the cellular component of the inner limiting membrane at 30 mm fetus. At 90 mm fetus radial fibers of M ller cells contained extensive smooth endoplasmic reticula and microtubules. In each specimen , apposing paired membrane specializations were classified as junctions without synaptic vesicles, conventional synapses and ribbon synapses. At 50 mm fetus the processes of neuroblasts in inner plexiform layer were interconnected by junctions without synaptic vesicles. Conventional synapses developed by addition of synaptic vesicles to initially vesicle-free junctions at 90 mm fetus. At 150 mm fetus ribbon synapses were first recognized by the inclusion of a prominent electron-dense material associated with synaptic vesicles. By 260 mm fetus conventional and ribbon synapses and junctions without synaptic vesicles formed similar to those found in the adult.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.48-50
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• 2000

The energetics at the succinate:quinone oxidoreductase segment of V. alginolyticus was studied using a fluorescence quenching technique with inside-out membrane vesicles. A transient generation of the membrane potential (inside-positive) and ${\Delta}pH$ (inside-acidic) occurred in the presence of KCN and succinate when ubiquinone-1 (Q1) was added. The membrane potential (\Delta\psi$) generated by the succinate; quinone oxidoreductase segment was completely collapsed by the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) and the membrane permeable anion $SCN^{-}$, whereas the ${\Delta}pH$ was completely collapsed by CCCP and $(NH_4)_2SO_4$. From these results, it was concluded that the succinate: quinone oxidoreductase segment as well as quinol oxidase [1] in the respiratory chain of V. alginolyticus generated $H^{+}$ electrochemical potential.

• Journal of Ginseng Research
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• v.15 no.2
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• pp.131-138
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• 1991

This study was carried out to investigate the development of endoplasmic reticulum and the formation of Protein body in the endosperm cell during seed formation of Panax ginseng C. A. Meyer with electron microscope. In the endosperm cell of early developmental process after pollination, vesicles that contain storage materials produced in rough endoplasmic reticulum incorporated into central vacuole. The central vacuole is gradually subdivided into several small-sized vacuoles and increased in number. Amorphous proteinaceous materials of high electron density are produced in rough endoplasmic reticulum. Rough endoplasmic reticulum increase in number and surround the protein body and vesicles circularly. Spherical proteinaceous granules with limited membrane appeared from the amorphous granules at the peripheral region of the rough endoplasmic reticulum. Gradually, storage materials are accumulated within the vacuole surrounded by spherosomes. Protein bodies are formed by interfusing between vacuoles and vesicles derived from rough endoplasmic reticulum which contained the amorphous protein of high electron density.

• Molecules and Cells
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• v.45 no.9
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• pp.603-609
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• 2022

Cells can communicate in a variety of ways, such as by contacting each other or by secreting certain factors. Recently, extracellular vesicles (EVs) have been proposed to be mediators of cell communication. EVs are small vesicles with a lipid bilayer membrane that are secreted by cells and contain DNA, RNAs, lipids, and proteins. These EVs are secreted from various cell types and can migrate and be internalized by recipient cells that are the same or different than those that secrete them. EVs harboring various components are involved in regulating gene expression in recipient cells. These EVs may also play important roles in the senescence of cells and the accumulation of senescent cells in the body. Studies on the function of EVs in senescent cells and the mechanisms through which nonsenescent and senescent cells communicate through EVs are being actively conducted. Here, we summarize studies suggesting that EVs secreted from senescent cells can promote the senescence of other cells and that EVs secreted from nonsenescent cells can rejuvenate senescent cells. In addition, we discuss the functional components (proteins, RNAs, and other molecules) enclosed in EVs that enter recipient cells.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.191-199
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• 1992

Selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of model membranes of total lipids (SPMVTL) extracted from synaptosomal plasma membrane vesicles (SPMV). The polarization (P), anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) of DPH in the inner monolayer were 0.031, 0.025, 0.033, and 0.070, respectively, greater than calculated for the outer monolayer of SPMVTL. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of n-alkanols on the individual monolayer structure of SPMVTL. n-Alkanols fluidized the hydrocarbon region of bulk SPMVTL, and the potencies of n-alkanols up to 1-nonanol increased with carbon chain length. It appears that the potencies in bilayer fluidization increase by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further increase in hydrocarbon length resulted in a decrease in pharmacological activity. The n-alkanols had greater fluidizing effects on the outer monolayer as compared to the inner monolayer of SPMVTL, even though these selective effects tended to become weaker as carbon chain length increased. Thus, it has been proven that n-alkanols exhibit selective rather than nonselective fluidizing effects within transbilayer domains of SPMVTL.

• Applied Microscopy
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• v.19 no.1
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• pp.34-48
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• 1989

The oval shaped pericardial cells are clustered along the lateral sides of the heart and irregularly connected with the heart. The cells are bounded by a basement membrane. The basement membranes of the connected two peicardial cells are irregularly linked each other there-fore funnels are formed. The multiple invaginations of the cell membrane are observed and septate junctions develope at the part of enterance of the cell membrane. The coated pits are appeared in the inner side of the invaginated cell membrane. The coated vesicles, tubular and spherical shaped vesicle, Golgi complex containing high electron densed material in the cisternae and mitochondria are observed in the cytoplasm and lysosomes are remarkably well developed. The whirled membrane structures in the multiformed complex bounded by single membrane are linked with low electron densed granules and spherical shaped small granules having high electron density with $0.03{\mu}m$ in diameter are located between the whirled membrane in a row and gradually secretes the granules and then they produced the multilamellar body. The lysosomal regions of cytoplasm of pericardial cell are appeared negative reaction to the acid phosphatase and according to the results of the electrophoresis, lipoproteins having acid phosphatase activity are contained. The axon is contacted with the pericardial cells.

• Animal cells and systems
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• v.3 no.2
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• pp.215-219
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• 1999

Monoclonal antibody for delta-9-tetrahydrocannabiol (THC Ab), conjugated with protein A-gold, was employed as a probe to detect THC localization in the gland and subjacent cells of chemically fixed bracts of Cannabis. THC was detected in the outer wall of the disc cells, fibrillar matrix, the surface feature of secretory vesicles, and sheath throughout development of the secretory cavity. The probe was absent from vesicles. Label was also present in anticlinal walls of disc cells and walls of dermal and mesophyll cells. Little or no THC Ab was present in disc cells and none were detected in control tissues. This distribution pattern of THC Ab was similar to that in tissues prepared by high pressure cryofixation-cryosubstitution. Consistent association of THC with wall and wall-derived materials suggests that cannnabinoids are synthesized outside the plasma membrane and bound to a wall component, where-upon they are transported to the cavity with wall materials released from the disc cell wall during development of the secretory cavity.