結核菌感染快速血清及側流向技術診斷技術之研究
Date Issued
2004
Date
2004
Author(s)
何憲武
DOI
922314B002362
Abstract
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.
Subjects
Serratia marcescens, two-component system, swarming motility, fatty acids,
quorum sensing signals.
quorum sensing signals.
Publisher
臺北市：國立臺灣大學醫學院醫學檢驗暨生物技術學系
Type
journal article
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