Bacterial Signalings and Regulation of Multicellular Behavior---Serratia marcescens Swarming as the Study Model

  • Lai, Hsin-Chih (PI)

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details

Abstract

A preliminary model has been established on the molecular mechanism of regulation of multicellular behavior such as swarming and sliding in Serratia marcescens. Components identified to be involved in such regulatory network include a FlhDC master operon regulatory system, a SpnI/R quorum-sensing system, a RsmA global inhibitory protein, a RssB-RssA two-component signal transduction system, a mobile transposon TnTIR carrying the spnIR genes, a dapA-nlpA genetic locus specifically regulates cell morphogenesis and swarming respectively, and a functionally unknown SpnT inhibiting sliding and chromosomal DNA resolution. At the same time, regulation of prodigiosin (an antibiotic derivative, a pigment and an immunosuppressive agent), phospholipase and nuclease production is also coordinately regulated. Through transposon mutagenesis, we have also identified many other genes involved in swarming regulation. Preliminary data showed that functions of these genes are closely related to regulation of flagellar system, metabolism of carbohydrates and sensing of oxidoreductive status within the cells. We also showed that ygfF, flhDC, shlBA, rssB and other related genes including two LPS-synthesis related genes and one cyoA gene are under the control of RssB-RssA. The regulation of RssB-RssA by saturated fatty acids and their biochemical phosphorelay reaction are confirmed. To further build on our findings to describe new aspects of the regulatory mechanisms that underlie regulation of virulence, biofilm formation and swarming/sliding, we will continue to characterize the bacterial signal transduction regulon, linking their relationship to environmental factors, biofilm formation and pathogenesis. Special emphasis will also be focused on how the RssB-RssA protein conformations are changed after activation, and identifying the environmental signals involved.

Project IDs

Project ID:PC9708-0141
External Project ID:NSC95-2320-B182-059-MY3
StatusFinished
Effective start/end date01/08/0731/07/08

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