Linked Life Data

16079332

Source:http://linkedlifedata.com/resource/pubmed/id/16079332

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 8
pubmed:dateCreated
2005-8-4
pubmed:abstractText
Changes in the cellular envelope are major physiological adaptations that occur when micro-organisms encounter extreme environmental conditions. An appropriate degree of membrane fluidity is crucial for survival, and alteration of membrane lipids is an essential adaptive response. Emerging data suggest that microbial cells may recognize alterations in their membrane viscosity resulting from certain environmental changes as a trigger for adaptive cellular responses. In Pseudomonas aeruginosa, the quorum-sensing (QS) system involves a complex regulatory circuitry that coordinates the expression of genes according to a critical population density. Interestingly, it has been shown that the QS system of P. aeruginosa can also be activated by nutritional stress, independently of the cell density, and therefore may be part of a more general adaptive response to stressful environmental conditions. In order to examine the proposed link between membrane properties and stress signalling, the effects of genetically engineered alterations of the membrane phospholipid composition of P. aeruginosa PAO1 on the activation of the stringent response and the QS system were examined. The lptA gene encoding a functional homologue of PlsC, an Escherichia coli enzyme that catalyses the second step of the phospholipid biosynthesis pathway, was identified and disrupted. Inactivation of lptA altered the fatty acid profile of phospholipids and the membrane properties, resulting in decreased membrane fluidity. This resulted in a premature production of the QS signals N-butanoyl- and N-hexanoyl-homoserine lactone (C4-HSL and C6-HSL) and a repression of 2-heptyl-3-hydroxy-4-quinolone (PQS) synthesis at later growth phases. The effects on C4- and C6-HSL depended upon the expression of relA, encoding the (p)ppGpp alarmone synthase, which was increased in the lptA mutant. Together, the findings support the concept that alterations in membrane properties can act as a trigger for stress-related gene expression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1350-0872
pubmed:author
pubmed:issnType
Print
pubmed:volume
151
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2529-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties.
pubmed:affiliation
BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland. c.baysse@ucc.ie
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't