• Development and Reproduction
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• v.7 no.2
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• pp.89-93
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• 2003

The present study observed the ultrastructure of testis of bluespotted mud hopper(Boleophthalmus pectinirostris), and sperrnatogenesis was discussed also. The testis was surrounded by a thin adventitia, inside which spermatocyst composed the parenchyma of testis. Each lobule was enwrapped by many spermatocysts, which were filled with different kinds of spermatogenic cell clusters at the same developmental stage. In the lobule lumen there are large numbers of spermatozoa The thin adventitia(outer wall) of testis was composed of outer epithelium, and the underlying layers, such as collagen fiber layer, and myoid tissue. The myoid tissue elongated into the inside of testis, became the main componentof interstitium between spermatocyst where sperrnatogenesis occurred. In addition interstitial cells containing dense homogeneous nucleus and abundant mitochondria were observed. Spermatogonia contained round nucleus with diffuse chromatin and nucleolus, and dense nuclear bodies surround by mitochondria in cytoplasm. The synaptonemal . complex was observed in primary spermatocytes clearly. Early spermatid presented larger round nucleus composed of granular chromatin, which was located in the center of cytoplasm. The nucleus of mid-spermatid composed of finely granular chromatin lied on one side of spermatid, and abundant mitochondria had migrated another side. A nuclear fossa appeared in the site near mitochondria in late-spermatid, and the centriole was formed in nuclear fossa.

• ALGAE
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• v.21 no.4
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• pp.479-483
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• 2006

In preparation of the biological samples for electron microscopy, the chemical fixation by glutaraldehyde, paraformaldehyde, and OsO4 has been generally used for a long time. However, the chemical fixation method has some problems: the infiltration time is a little bit long and the ultrastructure of cell or tissue transforms before complete fixation of sample. So, recently, cryo-fixation is considered more often in biomedical field. In this study, we compared High Pressure Freezing (HPF) method with chemical fixation method using a algal sample (Ptilota filicina J. Agardh), which was difficult to fix using chemical fixation method. In chloroplast, the ultrastructure of thylakoid lamella and phycobilisome can not show clearly by chemical fixation. In this study we could observe the ultrastructure of thylakoid lamella and phycobilisome of chloroplast very clearly using HPF fixation. An improved images of ultrastructures of nucleus, mitochondrion and floridean starch could obtain. These results suggest that HPF method is very useful method in algal specimen for electron microscopy.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.353-360
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• 2002

Although successful pronuclear formation and apposition were seen in porcine oocytes following mouse sperm injection, little is known on the morphology of male and female pronuclei following sperm injection. The objective of this study is to describe the ultrastructure of porcine zygote following murine sperm injection in relation to the chronology of pronuclear S phase. At 40h ~ 44h following in vitro maturation, Cumulus cells were removed in TCM-HEPES with 0.1% hyaluronidase. Then, spermatozoa was injected into the cytoplasm of oocytes. After. injection, all oocytes were transferred to NCSU23 medium and cultured at 39$^{\circ}C$ under 5% $CO_2$ in air. Oocytes were fixed in 2% glutaraldehyde in Dulbeccos phosphate-buffered saline and observed by Transmission Electron Microscopy. Nuclear precursor bodies were observed in each pronucleus. A cluster of large and small granules was attached in the nucleolus precursor body. After the apposition of male and female chromatin, chromatin condensation was observed throughout the nucleoplasm and nucleolus precursor bodies and condensed chromatin in contact with clusters of small and large granules and the nuclear envelope were found in apposed pronuclear regions. These results suggest that non-species specific nuclear cytoplasmic interactions take place during pronuclear formation and apposition following sperm injection.

• Applied Microscopy
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• v.15 no.1
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• pp.101-111
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• 1985

A study was undertaken to observe the distribution and ultrastructure of the sensory papillae of the liver and lung flukes which was obtained from experimentally infected rats and dogs. For this study, the rats were artificially infected with metacercariae isolated from Pseudorasbora parve, and the dogs were artificially infected with metacercariae isolated from Cambaroides similis. The liver flukes (Clonorchis sinensis) were collected from the bile ducts of the rats which were autopsied 5 weeks later since infection. The lung flukes (Paragonimus westermani) were collected from the lung of the dogs which were autopsied 3 months later since infection. With the collected worms, ultrastructure of sensory papillae was studied by means of a scanning and transmission electron microscope. The liver flukes were compared with the lung flukes. The results of the observation are as follows. 1. The sensory papillae of the liver flukes was classified into 3 types and most of sensory papillae were distributed on the oral sucker. 2. The sensory papillae of the lung flukes were distinguished 8 types. The sensory papilla type VIII was specifically distributed on the oral sucker and type I, II were distributed on the tegumental surface of the worm. The sensory papillae of the lung flukes were mostly observed between oral sucker and ventral sucker of the worm excusively 3. The sensory papillae of the liver flukes were distributed around the sucker while those of the lung flukes were developed between spine. 4. The sensory papillae were formed by many tegumental ridge in the liver flukes while was made of many small sensory papillae in the lung flukes. 5. The sensory cilia were observed between tegumental ridges in the sensory papilla of the liver flukes and also in lung flukes. And they are alike in that respect. 6. The sensory papillae were not developed in the posterior part of the liver and lung flukes but mostly nerve endings were formed in the tegumental syncytium, and it was connected with neuropile.

• Applied Microscopy
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• v.32 no.1
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• pp.39-44
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• 2002

The ultrastructure of the fertilized egg envelope from dark sleeper, Odontobutis obscurus interrupta belong to Eleotrididae was studied using scanning and transmission electron microscopes. The fertilized egg of dark sleeper was of transparent, ellipsoidal, adhesive and demersal type, and there were numerous oil droplets in the yolk sac and adhesive filaments in the area of the animal pole. The outer surface of egg envelope was smooth with pore canal. The fertilized egg envelope consisted of two layers, an outer nonadhesive layer and an inner layer, consisting of seven horizontal low electron-dense lamellae alternating with the middle electron dense interlamellae. These ultrastructural characters of fertilized egg envelope from dark sleeper can be utilized in taxonomy of teleost.

• Applied Microscopy
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• v.27 no.1
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• pp.31-46
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• 1997

Ultrastructure of mouse thymus was evaluated, following the administration of potassium dichromate and mercuric chloride, the heavy metals of evironmental pollutants. Potassium dichromate (20 mg/kg) or mercuric chloride solutions (10 mg/kg) were subcutanously injected to the mice. Six hours, three days and two weeks after the injections, animals were sacrificed. Thymic tissues were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solutions. The procedure was followed by the fixation in 1% osmium tetroxide solutions. Washed and dehydrated tissue-blocks were embedded in the araldite mixture. Ultra-thin sections were stained with uranyl acetate-lead citrate solutions. Results observed were as follows: 1. In electron microscopy, cortical population of thymocytes in the thymus of experimental groups were reduced. especially in the outer cortex. Subcapsular cortices of potassium dichromate treated mice were filled with many epithelial reticular cells, whereas the similar area of mercuric chloride-treated mice exhibited large intercellular spaces. 2. In the thymus of mercuric chloride treated group, large intercellular spaces were formed by shrinkage of epithelial reticular cells, and the space was invaded by numerous cytoplasmic projections of macrophages. Thymocytes nuded out from the shrunken cytoplasm of epithelial reticular cells, presented numerous microvilli. 3. In the thymus of potassium dicromate treated group, many activated macrophages and plasma cells migrated into thymic cortices. 4. In the perivascular spaces of thymic cortices of potassium dichromate- and mercuric chloride-treated mice, activated macrophages. plasma cells, collagen fibrils, and flocculent substance of exudated materials were exhibited. From the above findifgs, it was concluded that potassium dichromate or mercuric chloride could disturb the normal differentiation or 'education' of T cells in the thymic cortex. In turn, these heavy metals may hurt the immunological defense mechanism.

• Applied Microscopy
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• v.18 no.1
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• pp.60-76
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• 1988

Chick embryos which have received a single injection of the organophosphate compound, malathion (0.1 mg/0.05 ml, 0.5 mg/0.05 ml, 1.0 mg/0.05 ml or 2.0 mg/0.05 ml) via the yolk sac at certain times (2 days, 4 days or 6 days after incubation) have been investigated. After 9 days of incubation, chick embryos were harvested to examine the effects of malathion on the ultrastructure and the acetylcholinesterase(AChE) activity of the developing spinal cord. The effects of simultaneous injection of malathion and nicotinamide were also compared. On ultrastructural findings, neurons in the ventral horn of spinal cord showed to be inhibited in their differentiation by malathion; nuclear irregularity, separation of nuclear membranes, reduction of ribosomal distribution, and cytoplasmic vacuoles were observed. In the younger embryos treated with relatively high doses of malathion, nucleus and cytoplasmic organelles of neurons were severely destroyed, and the neurons were shown to be necrotic. On cytochemical study of AChE by electron microscope, the positive reaction products of AChE were localized at the membranes of nucleus and endoplasmic reticulum of neurons. Inhibition of AChE activity was severe in groups treated with relatively low doses of malathion. Nicotinamide (5.0 mg/0.05 ml) alleviated malathion-induced morphological alterations. In conclusion, it is suggested that malathion changes the ultrastructure and reduces. AChE activity in differentiating neurons, and the severity of which is consistently dose- and age-dependent.

• Applied Microscopy
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• v.28 no.1
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• pp.63-71
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• 1998

The spermatozoon of Squalidus gracilis majimae is approximately $36.6{\mu}m$ in length and is characterized by a spherical nucleils with the clear chromatin, a short midpiece containing the mitochondria, and a flagellum positioned tangentially to the nucleus. An acrosome is absent as in all teleost fishes. The nucleus is about $1.9{\mu}m$ in diameter and in its periphery contains the electron-lucent chromatin distinguished from the electron-dense chromatin occupying most of the nucleus. The shallow nuclear fossa contains the proximal centriole, instead of two centrioles in deep nuclear fossa in siluroids. The proximal and distal centrioles are oriented approximately $140^{\circ}$ to each other. The mitochondria of 10 or more in number are arranged in three layers and do not surround the axoneme. The asymmetrical distribution of the mitochondria and the eccentrical position of the nucleus with regard to the tail are the general pattern of the cyprinid spermatozoa. S. gracilis majimae spermatozoa have the most mitochondria and the deepest cytoplasmic canal among cyprinid species. The flagellum lacks the lateral fins.

• Applied Microscopy
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• v.41 no.1
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• pp.13-20
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• 2011

The ultrastructure of the matured egg envelope in Pond smelt, Hypomesus nipponensis belonging to Osmeridae, Osmeriformes were investigated by routine light and electron microscopes. The matured egg have two egg envelopes and have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. An outer egg envelope was surrounded by a follicular layer and outer surface of inner egg envelope have structure with high electron density. Also, the inner egg envelope consisted of 6 horizontal lamellae with higher electron density alternating with 5 interlamellae of lower electron density. Many grooves distributed on the outer surface of outer egg envelope, and the outer surface of inner egg envelope was covered by amorphous structures. In conclusion, the egg of teleost is surrounded by one egg envelope according to the studies on morphology of egg envelope up to the present. The fact that have two egg envelopes is a species specificity of Pond smelt and these ultrastructural characters of egg envelope can be utilized in taxonomy of teleost.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.607-613
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• 2014

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell $Ca^{2+}$ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at $-3^{\circ}C$, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of $Ca^{2+}$ from the intracellular space. Then, the imported $Ca^{2+}$ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of $Ca^{2+}$ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.