https://scholars.lib.ntu.edu.tw/handle/123456789/145945
標題: | 結核菌感染快速血清及側流向技術診斷技術之研究 | 作者: | 何憲武 | 關鍵字: | Serratia marcescens, two-component system, swarming motility, fatty acids, quorum sensing signals. | 公開日期: | 2004 | 出版社: | 臺北市:國立臺灣大學醫學院醫學檢驗暨生物技術學系 | 摘要: | Through mini-Tn5 transposon mutagenesis for screening swarming mutants that swarmed independent of temperature regulation in Serratia marcescens, a mutant named WC100 was isolated. Analysis of the DNA region flanking mini-Tn5 transposon identified a chromosomal DNA fragment comprising three genes encoding a pair of two-component system RssA-RssB, and a potential oxidoreductase protein YgfFSm. While long chain saturated fatty acids (SFAs) and long chain acyl homoserine lactone (AHL) quorum sensing signals are observed to inhibit swarming of the parent strain S. marcescens CH-1, swarming of WC100 and the rssA re-knock-out mutant strain CH-1ΔA was not inhibited. S. marcescens CH-1 and CH-1ΔA were used to host a recombinant plasmid pYS401 in which the ygfFSm promoter from S. marcescens CH-1 was fused to a promoterless Vibrio harveyi luxCDABE operon. Expression of ygfFSm in CH-1 was observed to reach its peak at about one hour after inoculation on MGM-casamino acids agar surface at 37°C, when cells are grown at the transitional stage between lag and log phase. Such a basal expression activity was rapidly reduced as cells are grown into log phase. Compare with the basal level activity of CH-1, long chain SFAs and 3-oxo-C12 quorum sensing signal activated ygfFSm expression. Furthermore, the ygfFSm expression level in CH-1ΔA was observed to be increased for 2.25-fold compared with that in CH-1 grown on MGM-casamino acids agar, and was further activated when long chain SFAs or 3-oxo-C12 AHL signal were added. These data showed that while long chain SFAs and AHL signals inhibit swarming, expression of ygfFSm is activated by these compounds in both S. marcescens CH-1 and CH-1ΔA. The ygfFSm expression is down-regulated by RssA as in rssA mutant CH-1ΔA, not only its expression activity is higher but is also maintained at a higher level for a longer time. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/27791 | 其他識別: | 922314B002362 | Rights: | 國立臺灣大學醫學院醫學檢驗暨生物技術學系 |
顯示於: | 醫學檢驗暨生物技術學系 |
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