• Applied Microscopy
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• v.34 no.3
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• pp.199-209
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• 2004

The migut epitheluim of the last instar larva in the mosquito larvae, Anopheles sinensis was observed with electron microscopes. The midgut epitheluim of the mosquito larva is composed of a single-layered columnar absorptive cells, regenerative cells and secretory granular cells. The free surface of the columnar absorptive cells has a regular array of microvilli 'brush border', while cell membranes close to the basal lamina are extrmely infolded and a lot of mitochondria are concentrated in those processes. The columnar absorptive cells also contain cell organelles expected to be found in absorptive cell. Midgut regenerative cells which are positioned basally in the epithelium form the groups, which are called 'nidi', composed of 1 or $2{\sim}3$ cells, they show darker appearance than the columnar absoptive cells. The secretory granular cells contain numerous electron dense granules, $200{\sim}400$ nm in diameter. The cone shaped secretory granular cells are located in the basal portion of the midgut epitheluim. The epithelium is surrounded by the subepithelial space and muscle bundles. The subepithelial space, which is filled with fibrous connective tissue, is innervated by many axon cells and tracheoles.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.59-65
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• 1993

We isolated Actinomycetes strain GMT 1155 and purified the active compound, MT 1155, on the morphological reversion of ts/NRK cell from the isolate. MT 1155 was identified as toyocamycin having antifungal and antitumor activities from physico-chemical properties and UV, IR, $^1H$-NMR, $^13C$-NMR and mass spectrum. MT 1155 showed the morphologically reversional activity on ts/NRK cell and the cytotoxicity on CTLL cell at the final concentrations of 1.7 JlM and 0.2 11M, respectively and its $IC_{50}$ value on protein kinase A enzyme was 2.3 $\mu$M. Also it had strong antifungal activity against several pathogenic fungi but not antibacterial activity. And it did not inhibit both protein kinase C activity and the bleb-formation of K562 cell induced by phorbol esters.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.479-484
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• 2000

흰쥐에 에탄올을 투여해 간 손상을 유도한 후 굼벵이를 투여해 굼벵이가 혈청과 간의 지진대사에 어떠한 영향을 미치는가를 조사하였다. 혈청지질 중 에탄올에 의해 증가된 triglyceride, 총 cholesterol은 굼벵이를 섭취시킴으로써 이의 수치를 감소시켰으며 HDL-cholesterol은 굼벵이의 섭취로 triglyceride 함량은 감소되었다. GOT와 GPT의 활성은 에탄올 투여시 정상식이에 비해 유의적인 증가를 보인 반면, 굼벵이의 섭취로 유의적인 감소를 나타내었다. (p<0.05). 에탄올 추여군의 간조직 세포는 세포질에 지방소적의 축적으로 세포질의 부분적인 괴사현상이 나타났으며 조면소포체와 mitochondria의 형태적 변형이 관찰되었다. 에탄올과 굼벵이의 병용투여군은 지방소적의 크기 및 양적 감소와 세포질의 괴사현상이 약간 회복 되었으나 조면소포체와 mitochondria의 수적인 증가는 미미하였다.

• Development and Reproduction
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• v.12 no.1
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• pp.1-8
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• 2008

Specific protocols to increase the differentiation of neuronal cells from embryonic stem (ES) cells have been well established, such as retinoic acid induction and lineage selection of neuronal cells. For the neuropathological studies, ES-derived neurons (ES neurons) must show normal physiological characteristics related to cell death and survival and should be maintained in vitro for a sufficient time to show insults-specific cell death without spontaneous death. When mouse ES cells were plated onto astrocytes monolayer after retinoic acid induction, most ES cells differentiated into neuronal cells, which were confirmed by the presence of specific neuronal markers, and the cultures were viable for at least four weeks. When these cultures were examined for vulnerability to glutamate excitotoxicity, ES neurons were vulnerable to excitotoxic insults mediated by agonist-specific receptors. The vulnerability to excitotoxic death increased with developmental age of ES neurons in vitro. Specific receptors for Neurotrophin and GDNF family ligands were present in ES neurons. GDNF and NT-3 could modulate the survival and excitotoxic vulnerability of ES neurons. The vulnerability and resistance to toxic insults, which are essential requirements of model culture systems for neuropathological studies, make ES neurons to a useful model culture system. Especially ES cell are highly amenable to genetic modification unlikely to primary neuronal cells, which will give us a chance to answer more complicated neurophysiological questions. Recently there was an outstanding attempt to explore the cellular toxicity using human ES cells (Schrattenholz & Klemm, 2007) and it suggested that ES cells could be a new model system for neurophysiological studies soon and go further a large-scale screening system for pharmacological compounds in the future.

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.69-73
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• 2002

For the practical use of nuecin protein, we tried to overexpress nuecin using Bm5 insect cell and Bombyx mori. We inserted nuecin cDNA into pBm10po1-Xa vector derived from B. mori nuclear polyhedrosis virus (BmNPV), and expressed in Bm5 cells and B. mori respectively. SDS-PAGE and Northern blot analysis showed an expressed of the protein when baculovirus expression vector system (BEVS) was used. The amount of intracellular protein is abundant, but the amount of extracellular protein is poor. The results suggest that the biologically active nuecin protein produced by using BEVS is poor because incresed level of misfolded nuecin by the strong promoter, polyhedrin and p 10 of BEVS, decrease the level of free chaperons and foldases by binding with them.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.246-250
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• 2018

Ameloblastoma is a benign neoplasm originating from odontogenic epithelium. It is the most common neoplasm in the jaws and is characterized by aggressive behavior and local invasion. Unicystic ameloblastoma (UA) has a unilocular feature in radiologic examination and a cystic feature histologically. Decompression and marsupialization are conservative method of treatment of large UA. The purpose of decompression and marsupialization are size reduction of the mass, which makes it easy to handle at total enucleation with protection of nerve damage and facial deformity. Here we report successful conservative treatment of extensive UA using decompression and marsupialization with a review of literatures.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.246-253
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• 1998

Heavy metal-tolerant microorganisms, such as Pseudomonas putida, P. aeruginosa, P. chlororaphis and P. stutzeri which possessed the ability to accumulate cadmium, lead, zinc and copper, respectively, were isolated from industrial wastewaters and mine wastewaters polluted with various heavy metals. The binding sites of heavy metal in the cells were investigated by chemical modification of functional groups the cell walls. To determine the binding sites of heavy metal in the cells, electrochemical charge of amine and carboxyl groups in the cell walls of heavy metal-tolerant microorganisms were chemically modified. Chemical modifications of amine groups did not affect the heavy metal uptake as compared to native cell walls. In contrast, modifications of carboxyl groups drastically decreased heavy metal uptake as compared to native cell walls, and electron microscopy confirmed that the form and structure of the heavy metal uptake were different from those of native cell walls. The results suggested that the carboxyl groups were the major sites of heavy metal uptake in the heavy metal-tolerant microorganism cell.

• Applied Microscopy
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• v.39 no.3
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• pp.261-266
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• 2009

This study aim to disclose a possible mechanism for the neuronal cell death induced by peripheral nerve injury following a spinal nerve ligation (SNL) as a neuropathic pain model. Male Sprague-Dawley rats (270~290 g) were used for this study. Pain threshold was evaluated for their response to mechanical (von Frey hairs) stimuli 1, 3, and 7 days after a tight ligation of L5 ventral ramus. In control group, the small ganglion cells were strongly stained with routine toluidine blue (TB), whereas the large ganglion cells showed a little bit weak stainity. Each large ganglion cell is surrounded by perineuronal satellite cells. In experimental groups, small ganglion cells showing apparent degenerative changes increased on 1 day, and showed a peak in degenerative cell number at 3 days group, and decreased gradually at 7 days group. We also found a small number of large-sized ganglion cells showing mild degenerative changes. However their satellite cells ware relatively intact with no typical findings throughout this experiment. Under the electron microscope, small ganglion cells showed various stage and typical features of the dark degeneration including mitochondrial swelling.

• Health and Mission
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• s.1
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• pp.12-20
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• 2004

복제된 동물이나 인간은 각종 기형이나 조기사망을 설령 극복해다 할지라도 필연적으로 조로에 빠질 수 밖에 없다. "텔로미어(telomere)"라는 각 염색체의 끝부분에 있는 특수한 염기서열에 따라 각 종자에 따른 수명은 이미 세포 안에 각인된 채 태어나기 때문에 이것이 어떻게 조작되고 변형된다 해도, 운명처럼 따라다니는 시간의 한계를 거스를 수 없는 것이다.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.169-175
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• 1989

To study the role of mutant precore region in expression and secretion of hapatitis B viral core antigen, we have cloned core antigen gene(HBc) with or without precore region in geterologous expression vectors containing SV40 promoter, yeast promoter, and lambda $P_{L}$ promoter. In COS cells transfected with plasmid containing C-gene with precore region, antigens were detected in both cell extract and cultured medium. However, in the cells transfected with plasmids containing C-gene without precore or with mutated precore region by one nucleotide (T) addition at the nucleotide 1,821, HBcAg was detected only in cell extracts. These results support that the mutation by one nucleotide addition shifted the initiation codon of precore region to 53 nucleotides upward and the elongated precore region also played a major role in the secretion of HBcAg in mammalian cells. In the case of yeast and E. coli, HBcAg was detected only in cell extracts in spite of the presence of precore region, which suggest that precore region could not affect HBcAg secretion in these system.