Molecular mimicry between Larrea divaricata Cav. plant and a reference strain of Pseudomonas aeruginosa

2020 ◽  
Vol 138 ◽  
pp. 103818
Author(s):  
Florencia Fátima Ferramola ◽  
Silvia del Valle Dávila ◽  
Corina Verónica Sasso ◽  
María Aída Mattar Domínguez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain ◽  
Molecular Mimicry ◽  
Larrea Divaricata

scholarly journals Study of Pseudomonas aeruginosa PPF-1 biofilm formation using microfluidics: effect of magnesium on biofilm detachment in engineered conduits

2021 ◽  
Author(s):  
William Y. Harvey ◽  
Cynthia Gagné-Thivierge ◽  
Sepideh Fakari ◽  
Jean Barbeau ◽  
Steve Charette ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Opportunistic Pathogen ◽  
Shear Stresses ◽  
Density Maps ◽  
Biofilm Detachment ◽  
Flow Systems ◽  
Dynamics Simulations

The bacterium Pseudomonas aeruginosa is an opportunistic pathogen in certain organisms, including humans, but can also survive and proliferate in natural and engineered water systems. Microfluidic technology can address hydrodynamic questions related to bacterial contamination of water flow systems and infrastructure. In this work, a microfluidic approach was devised to study the effect of shear stresses on biofilms from a dental unit waterline (DUWL)-isolated P. aeruginosa strain, PPF-1. During application of relevant shear stress levels to DUWLs, the response of the PPF-1 biofilm was observed and compared to a clinical P. aeruginosa reference strain, PAO1. The response measurements were repeated for biofilms exposed to additional Mg2+ ions. Using a microfluidic approach to transforming optical density maps into three-dimensional images, we applied computational fluid dynamics simulations and determined the critical shear stresses for biofilm sloughing. In the absence of Mg2+, PPF-1 biofilms showed weaker attachment than PAO1 biofilms, resulting in continuous slough/regrowth cycles triggered by applied shear stresses of 1.42 +/- 0.32 Pa. Introducing Mg2+ into the PPF-1 biofilm culture medium seemed to place the biofilm into a viscoplastic mechanical state, thereby increasing mechanical stability, which resulted in elevated tolerances to shear stresses up to a critical value of 5.43 +/- 1.52 Pa. This resulted in a propensity for less frequent but more catastrophic sloughing events like that observed for the PAO1 reference strain. This suggests that in a low ionic environment, biofilms from the PPF-1 strain can result in higher and more continuous ejection of biofilm materials, possibly leading to increased downstream colonization of engineered flow systems.

scholarly journals Mutations in β-Lactamase AmpC Increase Resistance of Pseudomonas aeruginosa Isolates to Antipseudomonal Cephalosporins

2015 ◽  
Vol 59 (10) ◽  
pp. 6248-6255 ◽  
Author(s):  
M. Berrazeg ◽  
K. Jeannot ◽  
Véronique Yvette Ntsogo Enguéné ◽  
I. Broutin ◽  
S. Loeffert ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain ◽  
Binding Pocket ◽  
Amino Acid Substitutions ◽  
Substrate Binding Pocket ◽  
Strain Pao1 ◽  
Gram Negative ◽  
Content Type ◽  
Omega Loop ◽  
New Mutations

ABSTRACTMutation-dependent overproduction of intrinsic β-lactamase AmpC is considered the main cause of resistance of clinical strains ofPseudomonas aeruginosato antipseudomonal penicillins and cephalosporins. Analysis of 31 AmpC-overproducing clinical isolates exhibiting a greater resistance to ceftazidime than to piperacillin-tazobactam revealed the presence of 17 mutations in the β-lactamase, combined with various polymorphic amino acid substitutions. When overexpressed in AmpC-deficientP. aeruginosa4098, the genes coding for 20/23 of these AmpC variants were found to confer a higher (2-fold to >64-fold) resistance to ceftazidime and ceftolozane-tazobactam than did the gene from reference strain PAO1. The mutations had variable effects on the MICs of ticarcillin, piperacillin-tazobactam, aztreonam, and cefepime. Depending on their location in the AmpC structure and their impact on β-lactam MICs, they could be assigned to 4 distinct groups. Most of the mutations affecting the omega loop, the R2 domain, and the C-terminal end of the protein were shared with extended-spectrum AmpCs (ESACs) from other Gram-negative species. Interestingly, two new mutations (F121L and P154L) were predicted to enlarge the substrate binding pocket by disrupting the stacking between residues F121 and P154. We also found that the reported ESACs emerged locally in a variety of clones, some of which are epidemic and did not require hypermutability. Taken together, our results show thatP. aeruginosais able to adapt to efficacious β-lactams, including the newer cephalosporin ceftolozane, through a variety of mutations affecting its intrinsic β-lactamase, AmpC. Data suggest that the rates of ESAC-producing mutants are ≥1.5% in the clinical setting.

scholarly journals Draft Genome Assembly of Pseudomonas aeruginosa Quality Control Reference Strain Boston 41501

2014 ◽  
Vol 2 (5) ◽  
Author(s):  
T. D. Minogue ◽  
H. E. Daligault ◽  
K. W. Davenport ◽  
S. M. Broomall ◽  
D. C. Bruce ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quality Control ◽  
Genome Assembly ◽  
Reference Strain ◽  
Draft Genome ◽  
Draft Genome Assembly

scholarly journals The Pseudomonas aeruginosa Reference Strain PA14 Displays Increased Virulence Due to a Mutation in ladS

PLoS ONE ◽  
2011 ◽  
Vol 6 (12) ◽  
pp. e29113 ◽  
Author(s):  
Helga Mikkelsen ◽  
Rachel McMullan ◽  
Alain Filloux
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain

scholarly journals Role of the MexEF-OprN Efflux System in Low-Level Resistance of Pseudomonas aeruginosa to Ciprofloxacin

2011 ◽  
Vol 55 (12) ◽  
pp. 5676-5684 ◽  
Author(s):  
Catherine Llanes ◽  
Thilo Köhler ◽  
Isabelle Patry ◽  
Barbara Dehecq ◽  
Christian van Delden ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain ◽  
Efflux Pump ◽  
Resistance Mechanisms ◽  
Efflux System ◽  
Content Type ◽  
Clinical Strains ◽  
Major Mechanism ◽  
Level Resistance

ABSTRACTIn this study, we investigated the resistance mechanisms to fluoroquinolones of 85 non-cystic fibrosis strains ofPseudomonas aeruginosaexhibiting a reduced susceptibility to ciprofloxacin (MICs from 0.25 to 2 μg/ml). In addition to MexAB-OprM (31 of 85 isolates) and MexXY/OprM (39 of 85), the MexEF-OprN efflux pump (10 of 85) was found to be commonly upregulated in this population that is considered susceptible or of intermediate susceptibility to ciprofloxacin, according to current breakpoints. Analysis of the 10 MexEF-OprN overproducers (nfxCmutants) revealed the presence of various mutations in themexT(2 isolates),mexS(5 isolates), and/ormvaT(2 isolates) genes, the inactivation of which is known to increase the expression of themexEF-oprNoperon in reference strain PAO1-UW. However, these genes were intact in 3 of 10 of the clinical strains. Interestingly, ciprofloxacin at 2 μg/ml or 4 μg/ml preferentially selectednfxCmutants from wild-type clinical strains (n= 10 isolates) and from first-step mutants (n= 10) overexpressing Mex pumps, thus indicating that MexEF-OprN represents a major mechanism by whichP. aeruginosamay acquire higher resistance levels to fluoroquinolones. These data support the notion that thenfxCmutants may be more prevalent in the clinical setting than anticipated and strongly suggest the involvement of still unknown genes in the regulation of this efflux system.

scholarly journals Complete Genome Sequence of Pseudomonas aeruginosa Reference Strain PAK

2019 ◽  
Vol 8 (41) ◽  
Author(s):  
Amy K. Cain ◽  
Laura M. Nolan ◽  
Geraldine J. Sullivan ◽  
Cynthia B. Whitchurch ◽  
Alain Filloux ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Reference Strain ◽  
Content Type ◽  
Laboratory Reference

We report the complete genome of Pseudomonas aeruginosa strain PAK, a strain which has been instrumental in the study of a range of P. aeruginosa virulence and pathogenesis factors and has been used for over 50 years as a laboratory reference strain.

scholarly journals Transcriptome analyses and biofilm-forming characteristics of a clonal Pseudomonas aeruginosa from the cystic fibrosis lung

2008 ◽  
Vol 57 (12) ◽  
pp. 1454-1465 ◽  
Author(s):  
Jim Manos ◽  
Jonathan Arthur ◽  
Barbara Rose ◽  
Pholawat Tingpej ◽  
Carina Fung ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Microarray Data ◽  
Reference Strain ◽  
Differentially Expressed Gene ◽  
Differentially Expressed ◽  
Strain Pao1 ◽  
Eastern Australia ◽  
Forming Characteristics ◽  
Insight Into

Transmissible Pseudomonas aeruginosa clones potentially pose a serious threat to cystic fibrosis (CF) patients. The AES-1 clone has been found to infect up to 40 % of patients in five CF centres in eastern Australia. Studies were carried out on clonal and non-clonal (NC) isolates from chronically infected CF patients, and the reference strain PAO1, to gain insight into the properties of AES-1. The transcriptomes of AES-1 and NC isolates, and of PAO1, grown planktonically and as a 72 h biofilm were compared using PAO1 microarrays. Microarray data were validated using real-time PCR. Overall, most differentially expressed genes were downregulated. AES-1 differentially expressed bacteriophage genes, novel motility genes, and virulence and quorum-sensing-related genes, compared with both PAO1 and NC. AES-1 but not NC biofilms significantly downregulated aerobic respiration genes compared with planktonic growth, suggesting enhanced anaerobic/microaerophilic growth by AES-1. Biofilm measurement showed that AES-1 formed significantly larger and thicker biofilms than NC or PAO1 isolates. This may be related to expression of the gene PA0729, encoding a biofilm-enhancing bacteriophage, identified by PCR in all AES-1 but few NC isolates (n=42). Links with the Liverpool epidemic strain included the presence of PA0729 and the absence of the bacteriophage gene cluster PA0632–PA0639. No common markers were found with the Manchester strain. No particular differentially expressed gene in AES-1 could definitively be ascribed a role in its infectivity, thus increasing the likelihood that AES-1 infectivity is multi-factorial and possibly involves novel genes. This study extends our understanding of the transcriptomic and genetic differences between clonal and NC strains of P. aeruginosa from CF lung.

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.

scholarly journals BIOSURFACTANTS SYNTHESIS BY PSEUDOMONAS AERUGINOSA BACTERIA ISOLATED FROM THE SURFACE OF MUSSELS OF THE BLACK SEA

2021 ◽  
pp. 71-83
Author(s):  
M. O. Finogenova ◽  
M. B. Galkin ◽  
A. S. Semenets ◽  
I. V. Prishchenko ◽  
G. S. Kaleva ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Black Sea ◽  
Nutrient Medium ◽  
Reference Strain ◽  
Wave Length ◽  
The Black Sea ◽  
Active Compounds ◽  
Surface Active ◽  
Culture Growth ◽  
Surface Active Compounds

Aim. Establishing of the ability to synthesize surface-active compounds by Pseudomonas aeruginosa bacteria isolated from the surface of Black Sea mussels. Methods. During the research several marine Pseudomonas spp strains isolated from petroleum hydrocarbon contaminated areas of Black Sea wereused: P. aeruginosa M1, P. aeruginosa M4 and P. aeruginosa PA01 as reference strain in suspension and biofilm cultures (LB and Giss media). Cultivation of Pseudomonas aeruginosa strains was performed at 37 °C for 120 and 168 hours. Planktonic culture growth was determined spectrophotometrically on the wave length 600 nm. Biofilm mass was determined spectrophotometrically on the wave length 592 nm by CV-test. The presence of surface-active compounds was determined in a drop test. The quantitative content of rhamnolipids was evaluated by the color reaction of rhamnose with orcin. Results. P. aeruginosa strains M1 and M4 isolated from Black Sea mussel’s surfaces synthesize 25% and 66% more surfactants than the reference strain PA01. All strains in Giss medium synthesized 10–20 times less rhamnolipids than in LB medium. In biofilm cultures the same biosurfactant synthesis dependence on the composition of the nutrient medium is observed as in suspension cultures. According to the intensity of rhamnolipid production in biofilm cultures, the studied strains can be arranged in the following row: P. aeruginosa M4 > P. aeruginosa M1 >> P. aeruginosa PA01.Conclusions. The strains of P. aeruginosa isolated from the Black Sea are more efficient producers of rhamnolipids than the reference strain of P. aeruginosa PA01; the intensity of biosynthesis of surfactants significantly depends on the composition of the nutrient medium and the method of cultivation.

scholarly journals Virulence factors regulation by the quorum-sensing and Rsm systems in the marine strain Pseudomonas aeruginosa ID4365, a natural mutant in lasR

2020 ◽  
Vol 367 (12) ◽  
Author(s):  
Miguel Cocotl-Yañez ◽  
Martín Paolo Soto-Aceves ◽  
Abigail González-Valdez ◽  
Luis Servín-González ◽  
Gloria Soberón-Chávez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Reference Strain ◽  
Ecological Niches ◽  
Human Pathogen ◽  
Strain Pao1 ◽  
Opportunistic Human Pathogen ◽  
Marine Strain

ABSTRACT Pseudomonas aeruginosa is an opportunistic human pathogen that is able to produce several virulence factors such as pyocyanin, rhamnolipids and elastase. In the clinical reference strain PAO1, synthesis of these virulence factors is regulated transcriptionally by quorum sensing (QS) and post-transcriptionally by the Rsm system. Herein, we investigated the role of these systems in the control of the pyocyanin, rhamnolipids and elastase production in the marine strain ID4365. We found that this strain carries a nonsense mutation in lasR that makes it a natural mutant in the Las QS system. However, its QS response is still functional with the Rhl system activating virulence factors synthesis. We found that the Rsm system affects virulence factors production, since overexpression of RsmA reduces pyocyanin production whereas RsmY overexpression increases its synthesis. Unexpectedly, and in contrast to the type strain PAO1, inactivation of rsmA increases pyocyanin but reduces elastase and rhamnolipids production by a reduction of RhlR levels. Thus, QS and Rsm systems are involved in regulating virulence factors production, but this regulation is different to the PAO1 strain even though their genomes are highly conserved. It is likely that these differences are related to the different ecological niches in which these strains lived.

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