scholarly journals Phenotypic Adaption of Pseudomonas aeruginosa by Hacking Siderophores Produced by Other Microorganisms

2020 ◽  
Vol 19 (4) ◽  
pp. 589-607 ◽  
Author(s):  
Quentin Perraud ◽  
Paola Cantero ◽  
Béatrice Roche ◽  
Véronique Gasser ◽  
Vincent P. Normant ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenotypic Plasticity ◽  
Iron Uptake ◽  
Opportunistic Pathogen ◽  
Growth Conditions ◽  
Growth Media ◽  
Cell Infection ◽  
Uptake Pathway ◽  
Pathway Expression ◽  
Strong Competition

Bacteria secrete siderophores to access iron, a key nutrient poorly bioavailable and the source of strong competition between microorganisms in most biotopes. Many bacteria also use siderophores produced by other microorganisms (exosiderophores) in a piracy strategy. Pseudomonas aeruginosa, an opportunistic pathogen, produces two siderophores, pyoverdine and pyochelin, and is also able to use a panel of exosiderophores. We first investigated expression of the various iron-uptake pathways of P. aeruginosa in three different growth media using proteomic and RT-qPCR approaches and observed three different phenotypic patterns, indicating complex phenotypic plasticity in the expression of the various iron-uptake pathways. We then investigated the phenotypic plasticity of iron-uptake pathway expression in the presence of various exosiderophores (present individually or as a mixture) under planktonic growth conditions, as well as in an epithelial cell infection assay. In all growth conditions tested, catechol-type exosiderophores were clearly more efficient in inducing the expression of their corresponding transporters than the others, showing that bacteria opt for the use of catechol siderophores to access iron when they are present in the environment. In parallel, expression of the proteins of the pyochelin pathway was significantly repressed under most conditions tested, as well as that of proteins of the pyoverdine pathway, but to a lesser extent. There was no effect on the expression of the heme and ferrous uptake pathways. Overall, these data provide precise insights on how P. aeruginosa adjusts the expression of its various iron-uptake pathways (phenotypic plasticity and switching) to match varying levels of iron and competition.

scholarly journals Phenotypic Adaptation of Pseudomonas aeruginosa in the Presence of Siderophore-Antibiotic Conjugates during Epithelial Cell Infection

2020 ◽  
Vol 8 (11) ◽  
pp. 1820
Author(s):  
Quentin Perraud ◽  
Paola Cantero ◽  
Mathilde Munier ◽  
Françoise Hoegy ◽  
Nicolas Zill ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenotypic Plasticity ◽  
Epithelial Cell ◽  
Iron Uptake ◽  
Iron Acquisition ◽  
Trojan Horse ◽  
Cell Infection ◽  
Uptake Pathway ◽  
Pathway Expression ◽  
Uptake Process

Iron acquisition pathways have often been considered to be gateways for the uptake of antibiotics into bacteria. Bacteria excrete chelators, called siderophores, to access iron. Antibiotic molecules can be covalently attached to siderophores for their transport into pathogens during the iron-uptake process. P. aeruginosa produces two siderophores and is also able to use many siderophores produced by other bacteria. We investigated the phenotypic plasticity of iron-uptake pathway expression in an epithelial cell infection assay in the presence of two different siderophore–antibiotic conjugates, one with a hydroxamate siderophore and the second with a tris-catechol. Proteomic and RT-qPCR approaches showed that P. aeruginosa was able to sense the presence of both compounds in its environment and adapt the expression of its iron uptake pathways to access iron via them. Moreover, the catechol-type siderophore–antibiotic was clearly more efficient in inducing the expression of its corresponding transporter than the hydroxamate compound when both were simultaneously present. In parallel, the expression of the proteins of the two iron uptake pathways using siderophores produced by P. aeruginosa was significantly repressed in the presence of both conjugates. Altogether, the data indicate that catechol-type siderophores are more promising vectors for antibiotic vectorization using a Trojan-horse strategy.

scholarly journals Pyoverdine-Mediated Iron Uptake in Pseudomonas aeruginosa: the Tat System Is Required for PvdN but Not for FpvA Transport

2006 ◽  
Vol 188 (9) ◽  
pp. 3317-3323 ◽  
Author(s):  
Romé Voulhoux ◽  
Alain Filloux ◽  
Isabelle J. Schalk
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Iron Uptake ◽  
Cytoplasmic Membrane ◽  
Signal Sequence ◽  
Iron Release ◽  
Outer Membrane Receptor ◽  
Uptake Pathway ◽  
Uptake Process ◽  
Tat System

ABSTRACT Under iron-limiting conditions, Pseudomonas aeruginosa PAO1 secretes a fluorescent siderophore called pyoverdine (Pvd). After chelating iron, this ferric siderophore is transported back into the cells via the outer membrane receptor FpvA. The Pvd-dependent iron uptake pathway requires several essential genes involved in both the synthesis of Pvd and the uptake of ferric Pvd inside the cell. A previous study describing the global phenotype of a tat-deficient P. aeruginosa strain showed that the defect in Pvd-mediated iron uptake was due to the Tat-dependent export of proteins involved in Pvd biogenesis and ferric Pvd uptake (U. Ochsner, A. Snyder, A. I. Vasil, and M. L. Vasil, Proc. Natl. Acad. Sci. USA 99:8312-8317, 2002). Using biochemical and biophysical tools, we showed that despite its predicted Tat signal sequence, FpvA is correctly located in the outer membrane of a tat mutant and is fully functional for all steps of the iron uptake process (ferric Pvd uptake and recycling of Pvd on FpvA after iron release). However, in the tat mutant, no Pvd was produced. This suggested that a key element in the Pvd biogenesis pathway must be exported to the periplasm by the Tat pathway. We located PvdN, a still unknown but essential component in Pvd biogenesis, at the periplasmic side of the cytoplasmic membrane and showed that its export is Tat dependent. Our results further support the idea that a critical step of the Pvd biogenesis pathway involving PvdN occurs at the periplasmic side of the cytoplasmic membrane.

scholarly journals cAMP and Vfr Control Exolysin Expression and Cytotoxicity of Pseudomonas aeruginosa Taxonomic Outliers

2018 ◽  
Vol 200 (12) ◽  
Author(s):  
Alice Berry ◽  
Kook Han ◽  
Julian Trouillon ◽  
Mylène Robert-Genthon ◽  
Michel Ragno ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Transcriptional Activation ◽  
Opportunistic Pathogen ◽  
Secretion System ◽  
Intracellular Camp ◽  
Virulence Determinants ◽  
Cell Infection ◽  
Content Type

ABSTRACT The two-partner secretion system ExlBA, expressed by strains of Pseudomonas aeruginosa belonging to the PA7 group, induces hemorrhage in lungs due to disruption of host cellular membranes. Here we demonstrate that the exlBA genes are controlled by a pathway consisting of cAMP and the virulence factor regulator (Vfr). Upon interaction with cAMP, Vfr binds directly to the exlBA promoter with high affinity (equilibrium binding constant [ K eq ] of ≈2.5 nM). The exlB and exlA expression was diminished in the Vfr-negative mutant and upregulated with increased intracellular cAMP levels. The Vfr binding sequence in the exlBA promoter was mutated in situ , resulting in reduced cytotoxicity of the mutant, showing that Vfr is required for the exlBA expression during intoxication of epithelial cells. Vfr also regulates function of type 4 pili previously shown to facilitate ExlA activity on epithelial cells, which indicates that the cAMP/Vfr pathway coordinates these two factors needed for full cytotoxicity. As in most P. aeruginosa strains, the adenylate cyclase CyaB is the main provider of cAMP for Vfr regulation during both in vitro growth and eukaryotic cell infection. We discovered that the absence of functional Vfr in the reference strain PA7 is caused by a frameshift in the gene and accounts for its reduced cytotoxicity, revealing the conservation of ExlBA control by the CyaB-cAMP/Vfr pathway in P. aeruginosa taxonomic outliers. IMPORTANCE The human opportunistic pathogen Pseudomonas aeruginosa provokes severe acute and chronic human infections associated with defined sets of virulence factors. The main virulence determinant of P. aeruginosa taxonomic outliers is exolysin, a membrane-disrupting pore-forming toxin belonging to the two-partner secretion system ExlBA. In this work, we demonstrate that the conserved CyaB-cAMP/Vfr pathway controls cytotoxicity of outlier clinical strains through direct transcriptional activation of the exlBA operon. Therefore, despite the fact that the type III secretion system and exolysin are mutually exclusive in classical and outlier strains, respectively, these two major virulence determinants share similarities in their mechanisms of regulation.

scholarly journals Genotyping of Different Pseudomonas Aeruginosa Morphotypes Arising from the Lower Respiratory Tract of a Patient Taken to an Intensive Care Unit

2008 ◽  
Vol 21 (4) ◽  
pp. 941-947 ◽  
Author(s):  
L. Putignani ◽  
R. Sessa ◽  
A. Petrucca ◽  
C. Manfredini ◽  
L. Coltella ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Intensive Care ◽  
Respiratory Tract ◽  
Lower Respiratory Tract ◽  
Opportunistic Pathogen ◽  
Growth Media ◽  
Environmental Bacterium ◽  
Genotypic Analysis

Pseudomonas aeruginosa is an opportunistic pathogen and an ubiquitous environmental bacterium. Fifty-seven days after hospitalization, we isolated three distinct P. aeruginosa morphotypes (smooth, rough and mucoid) from the lower respiratory tract of a patient admitted to a Cardiology Intensive Care Unit (ICU). Moreover, a group of nine colony variants, arising from the three P. aeruginosa isolates growing in laboratory growth media, were also isolated. The resulting 12 isolates were characterised for antibiotic resistance profile and subjected to genotypic analysis by fluorescent-Amplified Fragment Length Polymorphism (f-AFLP) and automated repetitive extragenic palindromic-PCR (rep-PCR) fingerprinting. The three smooth, rough and mucoid morphotypes presented different antibiotic resistance profiles and genotyping analysis showed that they belonged to distinct clones, indicating that at day 57 after the admission the patient was simultaneously colonized by three distinct P. aeruginosa isolates. On the other hand, the nine colony variants presented heterogeneous antibiotic resistance profiles and clustered together with the three parental isolates. The understanding of the link between genotype plasticity and antibiotic resistance may contribute to improving our knowledge of this life-threatening pathogen.

The PvdRT-OpmQ efflux pump controls the metal selectivity of the iron uptake pathway mediated by the siderophore pyoverdine in Pseudomonas aeruginosa

2011 ◽  
Vol 14 (7) ◽  
pp. 1696-1708 ◽  
Author(s):  
Mélissa Hannauer ◽  
Armelle Braud ◽  
Françoise Hoegy ◽  
Pascale Ronot ◽  
Anne Boos ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Iron Uptake ◽  
Efflux Pump ◽  
Uptake Pathway ◽  
Metal Selectivity

scholarly journals Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies

Microbiology ◽  
2020 ◽  
Vol 166 (8) ◽  
pp. 777-784 ◽  
Author(s):  
James Gurney ◽  
Sheyda Azimi ◽  
Sam P. Brown ◽  
Stephen P. Diggle
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Type Species ◽  
Natural Populations ◽  
Opportunistic Pathogen ◽  
Growth Media ◽  
Public And Private ◽  
Content Type ◽  
Private Goods ◽  
Link Type

In the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing (QS) is a social trait that is exploitable by non-cooperating cheats. Previously it has been shown that by linking QS to the production of both public and private goods, cheats can be prevented from invading populations of cooperators and this was described by Dandekar et al. (Science 2012;338:264–266) as ‘a metabolic incentive to cooperate’. We hypothesized that P. aeruginosa could evolve novel cheating strategies to circumvent private goods metabolism by rewiring its combinatorial response to two QS signals (3O-C12-HSL and C4-HSL). We performed a selection experiment that cycled P. aeruginosa between public and private goods growth media and evolved an isolate that rewired its control of cooperative protease expression from a synergistic (AND-gate) response to dual-signal input to a 3O-C12-HSL-only response. We show that this isolate circumvents metabolic incentives to cooperate and acts as a combinatorial signalling cheat, with higher fitness in competition with its ancestor. Our results show three important principles: first, combinatorial QS allows for diverse social strategies to emerge; second, restrictions levied by private goods are not sufficient to explain the maintenance of cooperation in natural populations; and third, modifying combinatorial QS responses could result in important physiological outcomes in bacterial populations.

scholarly journals Ferrous Iron Uptake in Cryptococcus neoformans

1998 ◽  
Vol 66 (9) ◽  
pp. 4169-4175 ◽  
Author(s):  
Eric S. Jacobson ◽  
Asha Prasad Goodner ◽  
Karin J. Nyhus
Keyword(s):  
Cryptococcus Neoformans ◽  
Iron Uptake ◽  
Opportunistic Pathogen ◽  
Metabolic Energy ◽  
Yeast Cells ◽  
Ferric Reductase ◽  
High Affinity ◽  
Steep Rise ◽  
Uptake Pathway ◽  
Uptake Activity

ABSTRACT Previous studies have implicated ferric reduction in the iron uptake pathway of the opportunistic pathogen Cryptococcus neoformans. Here we studied iron uptake directly, using55Fe in the presence of reductants. Uptake was linear with respect to time and number of yeast cells. The plot of uptake versus concentration exhibited a steep rise up to about 1 μM, a plateau between 1 and 25 μM, and a second steep rise above 25 μM, consistent with high- and low-affinity uptake systems. AKm for high-affinity uptake was estimated to be 0.6 μM Fe(II); 1 μM was used for standardized uptake assays. At this concentration, the uptake rate was 110 ± 3 pmol/106 cells/h. Iron repletion (15 μM) and copper starvation drastically decreased high-affinity iron uptake. Incubation at 0°C or in the presence of 2 mM KCN abolished high-affinity iron uptake, suggesting that uptake requires metabolic energy. When exogenous reducing agents were not supplied and the culture was washed free of secreted reductants, uptake was reduced by 46%; the remaining uptake activity presumably was dependent upon the cell membrane ferric reductase. Further decreases in free Fe(II) levels achieved by trapping with bathophenanthroline disulfonate or reoxidizing with potassium nitrosodisulfonate reduced iron uptake very drastically, suggesting that it is the Fe(II) species which is transported by the high-affinity transporter. The uptake of Fe was stimulated two- to threefold by deferoxamine, but this increment could be abolished by copper starvation or inhibition of the ferric reductase by Pt, indicating that Fe solubilized by this molecule also entered the reductive iron uptake pathway.

scholarly journals Anaerobiosis-Induced Loss of Cytotoxicity Is Due to Inactivation of Quorum Sensing in Pseudomonas aeruginosa

2011 ◽  
Vol 79 (7) ◽  
pp. 2792-2800 ◽  
Author(s):  
Kang-Mu Lee ◽  
Mi Young Yoon ◽  
Yongjin Park ◽  
Joon-Hee Lee ◽  
Sang Sun Yoon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Opportunistic Pathogen ◽  
Growth Conditions ◽  
Airway Epithelial Cells ◽  
Anaerobic Growth ◽  
Pathogenic Potential ◽  
Content Type ◽  
Airway Infections ◽  
Pai 1

ABSTRACTPseudomonas aeruginosa, an opportunistic pathogen of clinical importance, causes chronic airway infections in patients with cystic fibrosis (CF). Current literature suggests that pockets with reduced oxygen tension exist in the CF airway mucus. However, virulence features of this opportunistic pathogen under such conditions are largely unknown. Cell-free supernatant of the standard laboratoryP. aeruginosastrain PAO1 obtained from anaerobic culture, but not aerobic culture, failed to kill A549 human airway epithelial cells. Further investigation revealed that this reduced cytotoxicity upon anaerobiosis was due to the suppressed secretion of elastase, a virulence factor controlled byP. aeruginosaquorum sensing (QS). Both alacZ-reporter fusion assay and quantitative real-time PCR (RT-PCR) analysis demonstrated that transcription of the elastase-encodinglasBgene was substantially decreased during anaerobic growth compared with aerobic growth. Moreover, transcription of other genes controlled by the LasI/R QS system, such asrhlR,vqsR,mvfR, andrsaL, was also repressed under the same anaerobic growth conditions. Importantly, synthesis of 3-oxo-C12-HSL (PAI-1), an autoinducer molecule that mediates induction of the LasI/R QS system, was >22-fold decreased during anaerobic growth while C4-HSL (PAI-2), which mediates RhlI/R QS, was nondetectable under the same growth conditions. Transcription of thelasBgene was restored by exogenous supplementation with autoinducers, with PAI-2 more effective than PAI-1 orPseudomonasquinolone signal (PQS) at restoring transcription of thelasBgene. Together, these results suggest that anaerobiosis deprivesP. aeruginosaof the ability to regulate its virulence via QS and this misregulation attenuates the pathogenic potential of this important pathogen.

scholarly journals Three Pseudomonas aeruginosa strains with different protease profiles.

2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Mariola Andrejko ◽  
Agnieszka Zdybicka-Barabas ◽  
Monika Janczarek ◽  
Małgorzata Cytryńska
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Alkaline Protease ◽  
Reference Strain ◽  
Galleria Mellonella ◽  
Proteolytic Enzymes ◽  
Growth Conditions ◽  
Luria Bertani ◽  
Clinical Isolates ◽  
Pcr Analysis ◽  
Growth Media

The proteolytic activity of three Pseudomonas aeruginosa strains, ATCC 27853 - a reference strain, and two clinical isolates was tested. The activity was examined after culturing the bacteria in two different growth media: the minimal M9 medium and rich Luria-Bertani broth (LB). Based on zymograms and protease activity specific assays, it was concluded that the reference strain produced three proteolytic enzymes in the LB medium: protease IV, elastase B and elastase A, while alkaline protease was only produced in the M9 medium. The clinical isolates of P. aeruginosa produced elastase B and alkaline protease when grown in the LB medium and the minimal M9 medium, respectively. PCR analysis confirmed the presence of both the lasB gene encoding elastase B and aprA coding for alkaline protease in the genomes of the three P. aeruginosa strains analyzed. The expression of these genes coding for two important P. aeruginosa virulence factors was dependent on the growth conditions in all the strains studied. The contribution of the extracellular proteinases to the virulence of P. aeruginosa strains used in this study was investigated using an insect model, the greater wax moth Galleria mellonella.

Sign in / Sign up

Export Citation Format

Share Document