一個新的調控Serratia marcescens表面移行及毒素因子訊號傳遞系統之研究
Date Issued
2004
Date
2004
Author(s)
賴信志
DOI
922314B002356
Abstract
Serratia marcescens swarms at 30°C, but not at 37°C on a nutrient rich (LB)
agar surface. Mini-Tn5 mutagenesis of S. marcescens CH-1 yielded a mutant (WC100)
that swarms not only vigorously at 37°C, but also earlier and faster than the parent
strain at 30°C. Analysis of this mutant revealed that the transposon had inserted into a
gene (rssA) predicted to encode a bacterial two component signal transduction sensor
kinase, upstream of which, a potential response regulator gene (rssB) was located.
rssA and rssB insertion-deletion mutants were constructed through homologous
recombination and both exhibited similar swarming phenotypes on LB swarming agar
whereby swarming not only occurs at 37°C, but also initiates at a lower cell density,
on a surface of higher agar concentration and more rapidly than the parent strain at
30°C. Both mutants also exhibited increased haemolysin activity and altered cell
surface topologies compared with the parent CH-1 strain. Temperature and certain
saturated fatty acids (SFAs) were found to negatively regulate S. marcescens
swarming via the action of RssA-RssB. Analysis of the respective fatty acid profiles
of the parent, rssA and rssB mutants grown at 30oC or 37oC and different nutrition
conditions revealed a relationship between cellular fatty acid composition and
swarming phenotypes. The cellular fatty acid profile is further observed to be affected
by RssA and RssB. SFA-dependent inhibition of swarming was also observed in
Proteus mirabilis and Salmonella typhimurium, suggesting that either SFAs per se or
the modulation of cellular fatty acid composition and hence homeostasis of membrane
fluidity may be a conserved mechanism for regulating swarming motility in Gram
negative bacteria.
Subjects
Serratia marcescens, two-component system, swarming motility, fattyacids.
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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