Cyanobacterial resting cells, such as akinetes, are important seed cells for cyanobacteria’s early development and bloom. Due to their importance, various methods have been attempted to isolate resting cells present in the sediment. Ludox is a solution mainly used for cell separation in marine sediments, but finding an accurate method for use in freshwater is difficult. This study compared the two most commonly used Ludox methods (direct sediment treatment and sediment distilled water suspension treatment). Furthermore, we proposed a highly efficient method for isolating cyanobacterial resting cells and eDNA amplification from freshwater sediments. Most of the resting cells found in the sediment were akinete to the Nostocale and were similar to those of Dolichospermum, Cylindrospermum, and Aphanizomenon. Twenty times more akinetes were found in the conical tube column using the sediment that had no treatment than in the sample treated by suspending the sediment in distilled water. Akinete separated through Ludox were mainly spread over the upper and lower layers in the column rather than concentrated at a specific depth in the column layer. The mibC, Geo, and 16S rDNA genes were successfully amplified using the sediment directly in the sample. However, the amplification products of all genes were not found in the sample in which the sediment was suspended in distilled water. Therefore, 5 g to 10 g of sediment is used without pretreatment when isolating cyanobacterial resting cells from freshwater sediment. Cell isolation and gene amplification efficiency are high when four times the volume of Ludox is added. The Ludox treatment method presented in this study isolates cyanobacterial resting cells in freshwater sediment, and the same efficiency may not appear in other biotas. Therefore, to apply Ludox to the separation of other biotas, it is necessary to conduct a pre-experiment to determine the sediment pretreatment method and the water layer where the target organism exists.

Abstract
서 론
재료 및 방 법
    1. 퇴적물 채집
    2. Ludox 처리방법 A (직접처리)
    3. Ludox 처리방법 B (증류수 현탁)
    4. 남조류 세포계수
    5. DNA 추출 및 증폭
결과 및 고 찰
    1. 퇴적층에서 분리된 남조류 세포 형태
    2. Ludox 사용방법에 따른 퇴적물 남조류세포 분리 효율비교
    3. 유전자 증폭 비교
결 론
적 요
REFERENCES

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• 유경은(건국대학교 상허생명과학대학 환경보건과학과) | Kyeong-eun Yoo (Environmental Health Science, Sanghuh Life Science College, Konkuk University)
• 호혜인(건국대학교 상허생명과학대학 환경보건과학과) | Hye-in Ho (Environmental Health Science, Sanghuh Life Science College, Konkuk University)
• 박채홍(건국대학교 휴먼앤에코케어센터) | Chaehong Park (Human and Ecocare center, Konkuk University)
• 김현진(주식회사 평화엔지니어링) | Hyunjin Kim (Pyunghwa Engineering Consultants, Gwanyang Doosan Venture Digm)
• 황순진(건국대학교 상허생명과학대학 환경보건과학과) | Soon-Jin Hwang (Environmental Health Science, Sanghuh Life Science College, Konkuk University) Corresponding author