• The Korean Journal of Ecology
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• 제15권2호
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• pp.181-189
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• 1992

Dictyostelid cellular slime molds were quantitatibly isolated from the soils of mt.halla (above 900m in altitude), korea, according to the 'clonal isolation technique(cavender and raper, 1965a)'. Total fifteen species were found, including 1 new and 6 undescribed species.these are dictyostelium mucorodes, dictostelium minutem,polysphondylium pallidum fasciculatum, polysphondylium violaceum, dictyostelium flavidum,dictyostelium fasciculatum, polysphondylium violaceum, dictyostelium flavidum sp. n.(HL-1),dictyostelium aureo-stipes var. aureo-stipes, dictyostelium capitatum, dictyostelium giganteum,dictyostelium polycephalum,dictyostelium brefeldianum,dictyostelium macrocephalum, and dictyostelium sphaerocephalum, dictyostelium sp. (HL-2), dictyostelium sp. (CJ-9). D. mucoroides was the dominant species, and D. minutam,p.pallidum, d. fasciculatum, and p. violaceum were relatively common. d. polycephalum, d. brefeldianum, d. macrocephalum, dictyostelium sp. (HL-3), and d. sphaerocephalum were very rare. Species diversity appeared to be the highest in the deciduous broad-leaved forest from the soils of which 14 species were isolated. eight species were, including five undescribed species, isolated only from this forest soils. Number of isolates severely decrease at the forests above 1,500m in altitude.

• Journal of Plant Biology
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• 제33권3호
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• pp.159-168
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• 1990

The occurrence and distribution of cellular slime molds in major deciduous forests of South Korea were investigated. Ten species were isolated from the soils collected at ten sampling areas and cultured in hay infusion agar with E. coli. These include: Dictyostelium minutum Raper, Dictyostelium mucoroides Brefeld, Dictyostelium lacteum Van Tiegham, Dictyostelium polycephalum Raper, Dictyostelium fasciculutum Traub, Hohl and Cavender, Dictyostelium sp. Polysphondylium pallidum Olive, Polyshpondylium violaceum Brefeld, Copromyxellar sp. and Guttulinopsis vulgaris Olives. Among these species, Dictyostelium sp. and Copromyxellar sp. could not be identified. D. minutum and D. mucoroides occurred the most frequently in almost all the deciduous forests investigated in this study. Dictyostelium sp., D. fasciculutum and Copromyxella sp. occurred only in the north of the central region, but D. lacteum and D. polycephalum were found only in the south of that region. This indicates that distribution of these species may be affected by climate. The number of isolates per sampling site ranged from 2 to 6, averaging 4.3.

• The Korean Journal of Ecology
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• 제21권2호
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• pp.163-167
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• 1998

One new species of cellular slime molds, Dictyostelium caudabasis sp. nov. Shim et chang, is isolated from soils in the Quercus mongolica forest of Seorak monutain, South Korea. D. caudabasis is charaterized by small sorophores, scarecely phototrophic, irregularly or sparsely branches, capitate-simple or capitate-compound and sometimes obtuse-simple tips, and conical and sometimes clavate bases. Spore are elliptical, $6.52~4.82{\times}3.40~2.83{\mu}m(avg.\;5.72{times}3.17{\mu}m$), L/W index 1.70-1.92(avg. 1.80) without polar grnules.

• 미생물학회지
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• 제27권1호
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• pp.43-47
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• 1989

Characteristics and roles of protease released during the germination of Dictyostelium discoideum spores were investigated. When geat activated, the spores germinated, progressively releasing the protease into the extracellular medium. The protease activity exhibited high at pH 2.5. When cyclogeximide was added to culture, complete germination (emergence) and protease release were stopped. Addition of purified nonspecific protease to culture speeded up germination. These results suggest that excreted protease may play a role in removal of the spore wall.

• 통합자연과학논문집
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• 제16권2호
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• pp.69-74
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• 2023

In Dictyostelium , there are 15 Ras subfamilies, including 11 Ras, 3 Rap, 1 Rheb. The Ras proteins are involved in regulating various cell processes as switch proteins. The functions of many Ras proteins have been identified, but some of Ras proteins have not yet been identified. Here, we focused on identifying the roles of RasW among them. To investigate the functions of RasW in cell morphology, cell migration, and development in Dictyostelium , we compared the phenotypes of wild-type cells and rasW null cells. rasW null cells showed a larger, more spread-out morphology and reduced cell motility compared to wild-type cells. There was no significant difference between wild-type cells and rasW null cells during multicellular developmental process. These results suggest that RasW is involved in regulating cell morphology and cell migration in Dictyostelium.

• Journal of Plant Biology
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• 제36권1호
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• pp.9-17
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• 1993

Seven dictyostelid cellular slime molds isolated from the forest soils of Mt. Halla were described and illustrated. Dictyostelium flavidum Hong et Chang and three unidentified Dictyostelium, HL-2, HL-3 and CJ-9 were compared and discussed. All the isolates were cultivated on low nutrient media, 0.1- L-P(pH6) with Escherichia coli at 20-22$^{\circ}C$. Seven unrecorded species were all polar granule (PG) negative. These were Dictyostelium crassicaule Hagiwara, D. sphaerocephalum (Oud.) Sacc. et March, D. macrocephalum Hagiwara, Yeh et Chien, D. capitatum Hagiwara, D. brefeldianum Hagiwara, D. aureum var. aureum Cavender, Worley and Raper, and D. giganteum Singh.

• BMB Reports
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• 제46권2호
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• pp.86-91
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• 2013

Glucose effects on the vegetative growth of Dictyostelium discoideum Ax2 were studied by examining oxidative stress and tetrahydropteridine synthesis in cells cultured with different concentrations (0.5X, 7.7 g $L^{-1}$; 1X, 15.4 g $L^{-1}$; 2X, 30.8 g $L^{-1}$) of glucose. The growth rate was optimal in 1X cells (cells grown in 1X glucose) but was impaired drastically in 2X cells, below the level of 0.5X cells. There were glucose-dependent increases in reactive oxygen species (ROS) levels and mitochondrial dysfunction in parallel with the mRNA copy numbers of the enzymes catalyzing tetrahydropteridine synthesis and regeneration. On the other hand, both the specific activities of the enzymes and tetrahydropteridine levels in 2X cells were lower than those in 1X cells, but were higher than those in 0.5X cells. Given the antioxidant function of tetrahydropteridines and both the beneficial and harmful effects of ROS, the results suggest glucose-induced oxidative stress in Dictyostelium, a process that might originate from aerobic glycolysis, as well as a protective role of tetrahydropteridines against this stress.

• Molecules and Cells
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• 제41권2호
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• pp.103-109
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• 2018

Calcium ions are involved in the regulation of diverse cellular processes. Fourteen genes encoding calcium binding proteins have been identified in Dictyostelium. CBP7, one of the 14 CBPs, is composed of 169 amino acids and contains four EF-hand motifs. Here, we investigated the roles of CBP7 in the development and cell migration of Dictyostelium cells and found that high levels of CBP7 exerted a negative effect on cells aggregation during development, possibly by inhibiting chemoattractant-directed cell migration. While cells lacking CBP7 exhibited normal development and chemotaxis similar that of wild-type cells, CBP7 overexpressing cells completely lost their chemotactic abilities to move toward increasing cAMP concentrations. This resulted in inhibition of cellular aggregation, a process required for forming multicellular organisms during development. Low levels of cytosolic free calcium were observed in CBP7 overexpressing cells, which was likely the underlying cause of their lack of chemotaxis. Our results demonstrate that CBP7 plays an important role in cell spreading and cell-substrate adhesion. cbp7 null cells showed decreased cell size and cell-substrate adhesion. The present study contributes to further understanding the role of calcium signaling in regulation of cell migration and development.

• Journal of Plant Biology
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• 제35권4호
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• pp.393-401
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• 1992

한라산의 삼림 토양에서 앞서 보고된 신종 Dictyostelium flavidum Hong et Chang(노랑장대팡이)에 이어서 또하나의 신종이 기록되었다. 이것은 특징적인 넓은 꽃잎 모양의 집합체와 기부부근에 집중적인 긴 가지를 갖는 꽃모양의 군체를 나타내어 Dictyostelium floridum sp. nov. Hong et Chang(한국명 신칭 : 꽃구슬팡이)으로 명명되었다. D. floridum sp. nov.는 위의 특징 외에도, 1) 극낭이 뚜렷한 포자, 2) 기부에서 정단으로 올라갈수록 심하게 가늘어지는 자루, 3) 흔히 원뿔형이거나 구형이 기부, 4) 하나의 점액질에 단단히 묻혀 있는 여러 개의 기부, 5) 여러 층의 세포로 구성된 퇴형의 정단에 의해 특징된다. 또한 이 종은 온도에 매우 민감한 반응을 보이며, macrocyst나 microyst는 형성하지 않는다. 이 종은 처음 토양으로부터 분리된 이후 계속적인 계대배양을 통하여 형태적 특징뿐만 아니라 발생과정 및 성장습성이 자세히 관찰되었으며, 이러한 특징들과 데이터는 다른 유사한 종과 비교되었다. 이 종은 1990년 해발 1600 m 이상의 한라산 침엽수림 토양에서 처음 발견되었으며, 약한 영양배지인 0.1% lactose-peptone 배지에서 Escherichia coli와 함께 $18-22^{\circ}C$에서 이원배양되었다.

• The Korean Journal of Ecology
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• 제21권4호
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• pp.345-349
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• 1998

thirteen dictyostelid cellular slime molds were isolated from forest soils, cattle dung and manure inisland Ulneungdo, South Korea. They were ten species including Dictyostelium aureo-stipes var. aureo-stipes, D. brefeldianum, D. macrocephalum, D. caudabasis, D. sphaerocephalum, D. giganteum, D. crassicaule, Polysphondylium pallidum, P. violaceum and P. tenuissimum as well as three species unidentified. D. aureo-stipes var. aureo-species of genus Polysphondylium distributed widely. It was thought that species diversi쇼 was considerabley higher.