Comparative analyses of bacterial culturability and diversity in freshwater sediment by the most-probable-number cultivation techniques = 최확치 배양 기술을 통한 담수 침전물 서식 세균의 배양성 및 다양성 비교분석

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The culturability and diversity of abundant members of the domain Bacteria in freshwater sediment was investigated by a combination of various cultivation strategies and cultivation-independent 16S rDNA-based techniques. To capture an overall fraction of culturable bacteria from the sediment, a universal approach was carefully designed for adjustment of culture conditions, which comprised unsupplemented lake water as a medium, cycle of light and darkness, ambient temperature with a long-term incubation, anaerobic condition and use of the most-probable-number (MPN) single-cell quarantine technology. Bacterial culturability was examined with various MPN estimators that provided different levels of viable counts, which were for total bacterial fraction, colony-forming-bacteria (CFB) fraction, liquid-turbidifying-bacteria (LTB) fraction and total cultivated-bacteria fraction. Total count was indirectly measured by a new combination of epifluorescence microscopy and MPN estimation, resulting in a fast and non-biased result that was evaluated later by successful extinction of cells in most of the MPN culture plates. The cultivated population accounted for 13.4 % of the total count, which was approximately 60-160 times larger than the case of the colony forming population, indicating a remarkable improvement of microbial culturability compared to the classical plating technique. Growth turbidity was not effective in detecting bacterial culturability as the fraction of LTB was only 0.8 % of the total count. An isolate collection of 222 strains was then established by plating on oligotrophic medium and phylogenetically compared with a clone collection of 72 16S-rDNAs by sequencing and in silico amplified ribosomal DNA restriction analysis (ARDRA). On the basis of cluster analyses according to sequence similarity or ARDRA patterns, both of the collections were statistically stable in terms of species richness and evenness especially when they were subjected to lineage-sp...
Advisors
Lee, Sung-taikresearcher이성택researcher
Description
한국과학기술원 : 생명과학과,
Publisher
한국과학기술원
Issue Date
2009
Identifier
309250/325007  / 020035871
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 생명과학과, 2009.2, [ xvi, 146 p. ]

Keywords

most probable number (MPN); extinction culture; culturability; diversity; freshwater sediment; 최확치; 멸종배양; 배양성; 다양성; 담수 침전물; most probable number (MPN); extinction culture; culturability; diversity; freshwater sediment; 최확치; 멸종배양; 배양성; 다양성; 담수 침전물

URI
http://hdl.handle.net/10203/27654
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=309250&flag=dissertation
Appears in Collection
BS-Theses_Ph.D.(박사논문)
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