• Title/Summary/Keyword: dictyostelium

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A New Species of Cellular Slime Molds from Korea, Dictyostelium flavidum sp. nov. (한국산 세포성 점균의 1 신종)

  • 홍정수
    • Journal of Plant Biology
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    • v.35 no.3
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    • pp.197-203
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    • 1992
  • During the study of the distribution of cellular slime molds in Halla mountain of Korea, a new yellow-pigmented Dictyostelium was isloated. This exibited several distinctive features which differed from the published species, and was designated as a new species, Dictyostelium jlavidum sp. n. Hong et Chang (Type strain HL-1). It was cultivated at $20-22^{\circ}C$ on weak nutrient agar media, 0.1 L-P in association with Escherichia coli. Sorocarps were 4-10 mm or more in length, conspicuously yellow throughout or with sori, typically solitary, unbranched or sparsely and irregularly branched. Sorophores were strongly tapered from bases to tips. Bases were typically well-formed disks in form or conically expanded. Sori were yellow to yellowish in color, and the pigmentation intensified with age. Spores were long and thin elliptical, mostly $4.8-9.6{\times}1.9-3.8\;(ave.\;7.3{\times}2.8)\;\mu\textrm{m}$, L/B index about 2.4-2.8, without polar granules.anules.

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Cellular Slime Molds of Halla Mountain, III - Description of Polar Granule Positive Species - (한라산의 세포성 점균 (III) - 극낭 양성 종의 기록 -)

  • 홍정수
    • Journal of Plant Biology
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    • v.35 no.4
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    • pp.307-316
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    • 1992
  • A key to the species which have been isolated from the Korean forest soils was provided, and three unrecorded species found in the forest soils of Mt. Halla were described and illustrated. Twenty dictyostelid cellular slime molds had been found in Korean forest soils. Among these, nine species were PG positive, and eleven species were PG negative. Three species described in this study were all PG positive. These were Dictyastelium aurea-stipes Cavender, Raper et Norberg vaL aurea-stipes (new strain HL-5), Dictyastelium monachasiaides Hagiwara, PalysPhandylium tenuissimum Hagiwara. Morphological features and growth habits of these species were examined and compared, and their distribution patterns were illustrated.trated.

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Roles of RasU in Cell Motility and Development

  • Uri Han;Taeck Joong Jeon
    • Journal of Integrative Natural Science
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    • v.16 no.2
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    • pp.47-51
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    • 2023
  • Ras small GTPases are involved in regulating various cellular signaling pathways including cell migration, proliferation, and differentiation. Ras GTPase subfamily is comprised of 15 proteins; 11 Ras, 3 Rap, and one Rheb related protein. Some Ras proteins, such as RasC and RasG, have been identified for their major functions, but there are proteins whose functions have not been studied yet, such as RasU and RasX. Here, we investigated the roles of RasU in cell motility and development. RasU shows the highest homology with RasX. To investigate the functions of RasU, rasU null cells were used to observe the phenotype. Cells lacking RasU were larger and more spread than wild-type cells. These results indicate that RasU plays a negative role in cell spreading. In addition, we investigated the roles of RasU in cell motility and development of Dictyostelium cells and found that rasU null cells exhibited decreased random migration speed and delayed developmental process. These results suggest that RasU plays an important role in cell motility and development.

EF-hands in CBP7 are Important in the Process of Development

  • Dahyeon Kim;Taeck Joong Jeon;Byeonggyu Park;Dong Yeop SHIN
    • Journal of Integrative Natural Science
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    • v.17 no.1
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    • pp.31-41
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    • 2024
  • Calcium ions play an important role in development and intracellular signaling. Dictyostelium discoideum has 14 genes encoding calcium -binding proteins (CBPs), but the function of most CBPs during development has not yet been studied. In this study, we investigated the specific functions of CBP7, one of 14 CBPs, in development using RNA interference cell lines of CBP7, cell lines overexpressing CBP7, cell lines with point mutations in the EF-hand domain, and cell lines expressing fragment proteins. was intended to reveal. CBP7 consists of 169 amino acids and contains 4EF-hand domains. The CBP7-overexpressing cells showed complete loss of developmental process. These cells remained in the single-cell growth stage under development -inducing conditions, while wild-type cells formed aggregations within 6-8h of development and eventually formed fruiting bodies. The experiments using point-mutated CBP7 protein showed that all EF-hand domains of CBP7 were important for CBP7 to function during developmental process. These results suggest that CBP7 plays an important role in developmental processes across all EF-hand domains.

Occurrence of Cellular Slime Molds in Turfgrass Communities (잔디(Zoysia japonica Steud)군락에서의 세포성 점균의 출현)

  • 장남기;박미아;이정은
    • Asian Journal of Turfgrass Science
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    • v.7 no.2_3
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    • pp.113-120
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    • 1993
  • Dictyostelid cellular slime molds were quantitatibly isolated from Korean lawngrass turf in Seoul National University, Korea, by the 'Clonal Isolation Technique(Cavender and Raper, 1965a)'. Total six species were found. These are Dictyostelium sphaerocephalum. D. purpuream. D. flavidam, D. crassica ale, Polysphondilium pallidum. P. violaceum. D. sphaerocephalum was the dominant species and P. violaceum, D. flaviidum, D. crassicaule were rare. Compared with other region, species diversity and species richness of Korean lawngrass turf appeared to he low. The dominant species, however, is not very common in other plant communities, so it cnay he characteristic of Korean lawngrass turf.

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