• Animal cells and systems
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• 제10권3호
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• pp.115-120
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• 2006

Parkinson's disease (PD) is a neurodegenerative disease caused by selective degeneration of dopaminergic neurons in the substantia nigra. Mutations in ${\alpha}$-synuclein have been causally linked to the pathogenesis of hereditary PD. In addition, it is a major component of Lewy body found in the brains of sporadic cases as well. In the present study, we examined whether overexpression of wild type or PD-related mutant ${\alpha}$-synuclein induces unfolded protein response (UPR) and triggers the known signaling pathway of the resulting endoplasmic reticulum (ER) stress in SH-SY5Y cells. Overexpression of wild type, A30P, and A53T ${\alpha}$-synuclein all induced XBP-1 mRNA splicing, one of the late stage UPR events. However, activation of ER membrane kinases and upregulation of ER or cytoplsmic chaperones were not detected when ${\alpha}$-synuclein was overexpressed. However, basal level of cytoplsmic calcium was elevated in ${\alpha}$-synuclein-expressing cells. Our observation suggests that overexpression of ${\alpha}$-synuclein induces UPR independent of the known ER membrane kinase-mediated signaling pathway and induces ER stress by disturbing calcium homeostasis.

• 통합자연과학논문집
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• 제6권2호
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• pp.118-123
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• 2013

Korea, which is located in the middle-latitude area of the northern hemisphere, has four seasons. These seasons can be classified based on their months, mean temperatures, biology and natural phenomena. In this study, climatic changes were identified by biotic and temperature seasons, changing trends were compared by season, and the appropriateness of the biotic phenomena for the biotic season classification was examined. The data for this study included the mean temperatures, and biology phenomenon observation dates, which had been observed for 38 years from the ASOSs in seven Gwangju and Jeonnam regions. Limitations were found in the classification of the temperature and biotic seasons. Especially in the case of the biotic season based on a single life, the points of the first sighting and the initial sound fluctuated so much that the accuracy of the results was not guaranteed. Therefore, the life species had to be selected subject to detailed verification and accurate specifications, and to be applied to the meteorological phenomena. In addition, there were lives in the standard biology that could no longer be observed because of environmental pollution and climatic change, which indicates the need to protect the existing standard biology.

• 한국동물학회지
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• 제2권2호
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• pp.15-24
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• 1959

Concluding the result of this observation, authors obtained the table showing chromosome numbers which are consisted in each species as follow. Viewing on this result, authors recognized Acrididae are determined the sex with X-O type. 6 species of Family Acrididae and one species of Family Gryllotalpidae (on above table) had already calculated the number of chromosomes by some foreign observers. But another one species (Briodema tuberculatum dilatum STOLL) clarified by authors firstly in this observation. In 2nd spermatocyte of Trilophidia annulata YHUMBERG 1 to 3 Ist constriction satellites were observed, and each of the small bodies was connected with thin fibre and constituted with same or less breadth as the main chromosomes. If those are not the satellites, they should be the super-numerary chromosomes appearing a dot form. In this observation, among 48 species of Family Acrididae which have been found in Korea 18 species were calculated their chromosome numbers which were including 1 species calculated by authors newly. And authors have reobserved the chromosomes of Gryllotalpa africana PALISOT de BEUVOIS of Family Gryllotalpidae which was done by Japanese before.

• 한국균학회지
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• 제14권4호
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• pp.253-256
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• 1986

fusarium속(屬)에 속하는 3 종(種)인 F. solani, F. moniliforme, F.cocophilum을 실험재료로 하여 그들의 균사내(菌絲內)에서 일어나는 핵분열(核分裂)을 관찰하고, 그들의 염색체수(染色體數)를 확인하였다. Fusarium속(屬)의 핵분열(核分裂)은 생장(生長)하고 있는 끝부분(hyp-hal tip)에서 좀 더 관찰이 잘 되었고 염색체(染色體)의 형태(形態)는 대체로 점(點)(dot)모양이었으며, 확인한 염색체(染色體)의 수(數)는 F. solani는 n=8, F. moniforme는 8, F. cocophilum은 n=6개였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.111-111
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• 2011

Arrangement of individual atoms and molecules with atomic precision and understanding the resulting properties at the molecular level are ultimate goals of chemistry, biology, and materials science. For the past three decades, scanning probe microscopy has made strides towards these goals through the direct observation of individual atoms and molecules, enabling the discovery of new and unexpected phenomena. This talk will discuss the origin of forces governing motion of small organic molecules and their extended self-assembly into two-dimensional surface structures by direct observation of individual molecules using scanning tunneling microscopy (STM). In addition, atomic force microscopy (AFM) is utilized for the investigation of fundamental mechanisms of bone mineral dissolution by examining atomically well characterized simulated bone minerals under aqueous solution environments.

• Journal of Plant Biology
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• 제14권3호
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• pp.29-35
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• 1971

Various types of short culm rice mutants were obtained by means of gamma-ray irradiation. In the present paper morphological observation and analysis of silicate content of the mutants are reported. 1. Short culm type had more useful characters than bushy and dwarf types. 2. In short culm and bushy types the number of nodes both above and under ground was similar to the mother varieties, while in dwarf type it decreased. 3. In short culm types the variation of length of above-ground culm and internodes tended to vary relattive to the mother varieties. 4. Positive correlation was found between culm length and the first and fourth internode length in short culm type. 5. Silicate content increased in short culm type-the increment being variety specific.

• Journal of Plant Biology
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• 제13권3호
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• pp.17-19
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• 1970

Histological observation of micropore-originated haploid rice callus was reported previously. Present study was attempted to clarify the growth or development of the calli when they were transferred to differentiation media prepared exclusively for differentiation of plantlets. When the callus was transferred to differentiation medium, the cells and tissues became radially elongated. Meristematic tissues were present but few in number, and their structures were quite different from those grown in the propagaton medium. Differentiation of tracheid, chloroplast, and epidermis-like cell layer, and formation of gap in the callus tissue were more conspicuous in differentiation media. Approximately ten days after transfer of callus to differentiation medium, plantlet was formed.

• Journal of Periodontal and Implant Science
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• 제37권3호
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• pp.575-584
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• 2007

The present study was performed to evaluate the effect of citric acid on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, and HA coated surface were utilized. Pure titanium machined surface and HA coated surface were rubbed with pH 1 citric acid for 30s., 45s., 60s., 90s., and 120s. respectively. Then, the specimens were processed for scanning electron microscopic observation. The following results were obtained. 1. The specimens showed a few shallow grooves and ridges in pure titanium machined surface implants. The roughness of surfaces conditioned with pH 1 citric acid was slightly increased. 2. In HA-coated surfaces, round particles were deposited irregularly. The specimens were not significant differences within 45s. But, began to be changed from 60s. The roughness of surfaces was lessened and the surface dissolution was increased relative to the application time. In conclusion, pure titanium machined surface implants and HA coated surface implants can be treated with pH 1 citric acid for peri-implantitis treatment if the detoxification of these surfaces could be evaluated.

• Animal cells and systems
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• 제1권3호
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• pp.491-496
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• 1997

When olfactory placodes are transplanted at stages 23/24 from Xenopus laevis to Xenopus borealis hosts of the same age, it is possible to distinguish the cell populations of the host and donor due to the peculiar nuclear Q bands specific to X. borealis. I have replaced the eye anlage in each of a number of X. borealis with the transplanted olfactory placode of an individual X. laevis, or vice versa. In most instances, the placode of the donor fuses with that of the host. When fusion occurs, but not when the host and donor orqans grow separately, the cells of the donor were replaced gradually and according to a characteristic pattern by cells of the host. The basal cells of the donor were the first to be replaced, followed by the more matured cells of the sensory epithelium. This cellular substitution, proceeding in an orderly fashion from bottom to upper layers of the epithelium, depends on the fusion of the two organs. This observation suggests intercellular contacts in the mitotic zone of the two organs favor the host's cells over those of the donor.

• Applied Microscopy
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• 제18권2호
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• pp.167-176
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• 1988

Extrachromosomal circular DNA complexes from erythrocytes and splenocytes isolated from Carassius carassius were examined by mica-press-absorption method. The method was described that released small polydisperse circular DNA molecules in situ from the erythrocytes and the splenocytes and that allows selective observation of the small circular DNA complexes bound to cellular components. The released polydisperse circular DNA complexes were absorbed preferentially on mica in a divalent cation-free medium then processed for electron microscopy. Small circular DNAs showed a heterogeneous size distribution of $2{\sim}10{\mu}m$ with a mean contour length of $4.3{\mu}m$ for the circulating erythrocytes and that of $0.7{\sim}3.6{\mu}m$ with a mean contour of length $2.04{\mu}m$ for the splencytes. Cells contained $100{\sim}300$ copies and $300{\sim}700$ copies obtained from the erythrocytes and the splenocytes, repectively. Possible biological functional implications for size distribution of extrachromosomal circular DNAs are discussed.