DksA represses ribosomal gene transcription in <i>Pseudomonas aeruginosa</i> by interacting with RNA polymerase on ribosomal promoters

Perron, Karl; Comte, Rachel; Delden, Christian van

doi:10.1111/j.1365-2958.2005.04597.x

Cited by 60 publications

(60 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To assess the role of RelA, we inactivated lptA in a relA background and examined C4-HSL, C6-HSL and PQS production in the relA single mutant and in the relA lptA double mutant. In contrast to E. coli, in which the SpoT enzyme can also catalyse ppGpp formation, a relA mutant of P. aeruginosa produces no detectable amount of ppGpp (Erickson et al, 2004;Perron et al, 2005). As shown in Fig.…”

Section: Resultsmentioning

confidence: 94%

“…In turn, this activation of RelA results in increased expression of the lasI and rhlI genes, which direct synthesis of N-AHL cell-cell signalling molecules. Since the function of RelA is to produce ppGpp and (p)ppGpp (Erickson et al, 2004;Perron et al, 2005), it is likely that increased expression of the N-AHL-synthase genes arises because of elevated levels of ppGpp in the lptA mutant. Indeed, a link between relA and the N-AHLs-based QS system has been reported previously (Van Delden et al, 2001;Erickson et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties

et al. 2005

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties

et al. 2005

View full text Add to dashboard Cite

show abstract

“…In an E. coli strain defective in DksA protein, transcription of the fis operon, expression of which was known to actively occur during exponential growth, was extended into the stationary phase (51). In addition, P. aeruginosa DksA represses rRNA gene expression under both actively growing and stringent response conditions (52). Based on our results, the effect of dksA gene deletion was significantly more evident in the ppGpp-overproducing ⌬relA ⌬spoT double mutant than in the wild type strain, further suggesting that the role of DksA is amplified under the condition of ppGpp accumulation.…”

Section: Discussionmentioning

confidence: 99%

Cholera Toxin Production during Anaerobic Trimethylamine N-Oxide Respiration Is Mediated by Stringent Response in Vibrio cholerae

Park

Yoon

et al. 2014

Journal of Biological Chemistry

View full text Add to dashboard Cite

Background: Cholera toxin (CT) production is induced during anaerobic respiration with trimethylamine N-oxide (TMAO) in Vibrio cholerae. Results: A bacterial stringent response to nutrient starvation was activated during anaerobic TMAO respiration and influenced CT production. Conclusion: CT production during anaerobic TMAO respiration is mediated by stringent response in V. cholerae. Significance: A mechanism of TMAO-stimulated CT production is uncovered.

show abstract

“…In support of this finding, sequencing of the relA, spoT, and dksA genes in strains of the b genotype did not reveal any mutations that would alter the functions of the encoded proteins (data not shown). RelA, SpoT, and DksA are required for normal stringent regulation in many bacteria, including P. aeruginosa (42,43,45).…”

Section: Discussionmentioning

confidence: 99%

In Situ Growth Rates and Biofilm Development of Pseudomonas aeruginosa Populations in Chronic Lung Infections

et al. 2008

View full text Add to dashboard Cite

The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung infections in cystic fibrosis (CF) patients for more than 20 years. We used fluorescence in situ hybridization (FISH) directly on sputum specimens to examine the spatial distribution of the infecting P. aeruginosa cells. Mucoid variants were present in sputum as cell clusters surrounded by an extracellular matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of rRNA in bacteria isolated from sputa was measured and correlated with the rRNA contents of the same bacteria growing in vitro at defined rates. The results showed that most cells were actively growing with doubling times of between 100 and 200 min, with some growing even faster. Only a small stationary-phase subpopulation seemed to be present in sputa. This was found for both mucoid and nonmucoid variants despite their different organizations in sputum. The results suggest that the bacterial population may be confronted with selection forces that favor optimized growth activities. This scenario constitutes a new perspective on the adaptation and evolution of P. aeruginosa during chronic infections in CF patients in particular and on long-term infections in general.

show abstract

DksA represses ribosomal gene transcription in Pseudomonas aeruginosa by interacting with RNA polymerase on ribosomal promoters

Cited by 60 publications

References 53 publications

Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties

Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties

Cholera Toxin Production during Anaerobic Trimethylamine N-Oxide Respiration Is Mediated by Stringent Response in Vibrio cholerae

In Situ Growth Rates and Biofilm Development of Pseudomonas aeruginosa Populations in Chronic Lung Infections

Contact Info

Product

Resources

About