Proteus mirabilis 新quorum-sensing系統及其作為新藥發展及活菌疫苗構築之研究
Date Issued
2002
Date
2002
Author(s)
賴信志
DOI
902320B002110
Abstract
Serratia marcescens swarming behavior is characterized by continuous populational
surface migration on swarming agar at 30°C, but not at 37°C. The underlying
mechanism how S. marcescens population starts to initiate swarming and the
temperature-dependent regulation of swarming behaviour are currently
uncharacterized. We identify in S. marcescens a genetic locus that, when mutated,
results in a ”super-swarming” phenotype, which is not only defective in the temporal,
but also in the temperature-dependent control of swarming behaviours. The gene
mutated (rssA, Regulation of Serratia Swarming A) is homologous to membrane
sensor histidine kinases of the two-component family of regulatory proteins,
suggesting that RssA may function as a sensor of environmental conditions required
to regulate swarming migration. Factors already identified to be involved in regulation
of swarming migration are not affected in this mutant. These include amount of
flagellum synthesis, activity of swimming motility, surfactant production, and
synthesis of extracellular polysaccharide. Here we report that long chain fatty acids
and temperature shift acting as the signal cues regulate S. marcescens CH-1 swarming
through the RssA/RssB two component signal transduction system. We find that long
chain fatty acids and temperature upshift negatively regulate the CH-1 swarming
through influencing pattern of cellular fatty acid profile. The RssA-RssB
two-component system mediates this response, as both partners are required to sense
and transduce the signals. Fatty acid profile analysis strongly indicates that long chain
fatty acid and temperature affects the signaling state of the RssA sensor protein by
increasing the incorporation of the low0melting point fatty acids into membrane
phospholipid. We propose that both increase in membrane fluidity at constant
temperature and a temperature upshift influences fatty acid synthesis and swarming
by the same mechanism. Similar phenomena of long chain fatty acid inhibition were
also observed in swarming regulation of Proteus mirabilis and Salmonella
typhimurium. Thus, the fatty acid profile and two component signaling pathway might
provide a novel and common mechanism for regulation of swarming behaviour of not
only S. marcescens, but also other swarming bacteria under different physiological
culture conditions.
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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