A eukaryotic-type signalling system of Pseudomonas aeruginosa contributes to oxidative stress resistance, intracellular survival and virulence

Goldová, Jana; Ulrych, Aleš; Hercík, Kamil; Branný, Pavel

doi:10.1186/1471-2164-12-437

Cited by 49 publications

(36 citation statements)

References 78 publications

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“…Doubling times were as follows: 22.42 ± 2.1 minutes for LAC91, 33.44 ± 3.0 minutes for KH38, 37.98 ± 5.4 minutes for HH49, 24.92 ± 1.8 minutes for HH36, and 157.17 ± 19.4 minutes for PA01. S. aureus has previously reported doubling times of between 24 and 57 minutes [32][33][34], while P. aeruginosa has reported doubling times of between 100 and 200 minutes [35,36]. Therefore, there is excellent agreement between the current results and previous results in the field.…”

Section: Resultssupporting

confidence: 84%

Wavelength-normalized spectroscopic analysis of Staphylococcus aureus and Pseudomonas aeruginosa growth rates

McBirney

Trinh

Wong-Beringer

et al. 2016

Biomed. Opt. Express

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Optical density (OD) measurements are the standard approach used in microbiology for characterizing bacteria concentrations in culture media. OD is based on measuring the optical absorbance of a sample at a single wavelength, and any error will propagate through all calculations, leading to reproducibility issues. Here, we use the conventional OD technique to measure the growth rates of two different species of bacteria, Pseudomonas aeruginosa and Staphylococcus aureus. The same samples are also analyzed over the entire UV-Vis wavelength spectrum, allowing a distinctly different strategy for data analysis to be performed. Specifically, instead of only analyzing a single wavelength, a multiwavelength normalization process is implemented. When the OD method is used, the detected signal does not follow the log growth curve. In contrast, the multi-wavelength normalization process minimizes the impact of bacteria byproducts and environmental noise on the signal, thereby accurately quantifying growth rates with high fidelity at low concentrations.

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Section: Resultssupporting

confidence: 84%

Wavelength-normalized spectroscopic analysis of Staphylococcus aureus and Pseudomonas aeruginosa growth rates

McBirney

Trinh

Wong-Beringer

et al. 2016

Biomed. Opt. Express

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“…The ability of the variants to resist macrophage-mediated phagocytosis was assessed using a modified version of the method described by Goldova et al (29). The immortalized murine macrophage cells J774 were seeded in 96-well plates (Costar) at a concentration of 5 ϫ 10 5 cells/ml and incubated overnight (37°C and 5% CO 2 ).…”

Section: Methodsmentioning

confidence: 99%

Evolution of Pseudomonas aeruginosa Virulence as a Result of Phage Predation

Hosseinidoust

Ven

Tufenkji

2013

Appl Environ Microbiol

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The rapid increase in the emergence of antibiotic-resistant bacteria has attracted attention to bacteriophages for treating and preventing bacterial infections. Bacteriophages can drive the diversification of Pseudomonas aeruginosa, giving rise to phageresistant variants with different phenotypes from their ancestral hosts. In this study, we sought to investigate the effect of phage resistance on cytotoxicity of host populations toward cultured mammalian cells. The library of phage-resistant P. aeruginosa PAO1 variants used was developed previously via experimental evolution of an isogenic host population using phages PP7 and E79. Our results presented herein indicate that the phage-resistant variants developed in a heterogeneous phage environment exhibit a greater ability to impede metabolic action of cultured human keratinocytes and have a greater tendency to cause membrane damage even though they cannot invade the cells in large numbers. They also show a heightened resistance to phagocytosis by model murine macrophages. Furthermore, all isolates produced higher levels of at least one of the secreted virulence factors, namely, total proteases, elastase, phospholipase C, and hemolysins. Reverse transcription-quantitative PCR (RT-qPCR) revealed upregulation in the transcription of a number of genes associated with virulence of P. aeruginosa for the phage-resistant variants. The results of this study indicate a significant change in the in vitro virulence of P. aeruginosa following phage predation and highlight the need for caution in the selection and design of phages and phage cocktails for therapeutic use.

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“…The phagocytic index refers to the number of bacteria inside each cell. An antibiotic protection assay, described previously (42), was used to analyze bacterial survival within macrophages. For this assay, following the indicated time of phagocytosis, cells were washed 3 times with PBS, and extracellular bacteria were killed by incubating cells with growth medium containing amikacin (400 g/ml).…”

mentioning

confidence: 99%

Regulation of Rab5 Function during Phagocytosis of Live Pseudomonas aeruginosa in Macrophages

et al. 2013

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Pseudomonas aeruginosa, a Gram-negative opportunistic human pathogen, is a frequent cause of severe hospital-acquired infections. Effectors produced by the type III secretion system disrupt mammalian cell membrane trafficking and signaling and are integral to the establishment of P. aeruginosa infection. One of these effectors, ExoS, ADP-ribosylates several host cell proteins, including Ras and Rab GTPases. In this study, we demonstrated that Rab5 plays a critical role during early stages of P. aeruginosa invasion of J774-Eclone macrophages. We showed that live, but not heat-inactivated, P. aeruginosa inhibited phagocytosis and that this occurred in conjunction with downregulation of Rab5 activity. Inactivation of Rab5 was dependent on ExoS ADPribosyltransferase activity, and in J744-Eclone cells, ExoS ADP-ribosyltransferase activity caused a more severe inhibition of phagocytosis than ExoS Rho GTPase activity. Furthermore, we found that expression of Rin1, a Rab5 guanine exchange factor, but not Rabex5 and Rap6, partially reversed the inactivation of Rab5 during invasion of live P. aeruginosa. These studies provide evidence that live P. aeruginosa cells are able to influence their rate of phagocytosis in macrophages by directly regulating activation of Rab5. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen capable of causing acute and chronic infections in immunocompromised individuals. P. aeruginosa infection is also a serious problem for patients hospitalized with AIDS, cancer, cystic fibrosis, and burns (1-4). The type III secretion (T3S) system allows Gram-negative bacteria to produce and translocate effector proteins into the cytoplasm of host cells. While the T3S system is conserved among distantly related pathogens, secreted effectors are pathogen specific (5). The secretion and translocation of T3S effectors into the cytosol of animal or plant cells initiates a biochemical cross talk between pathogen and host (6). Four T3S effectors have been identified in P. aeruginosa: ExoS, ExoT, ExoU, and ExoY. Each effector functions differently to help create an environment inside the human host that favors bacterial survival and propagation in tissue.T3S effectors contribute to the ability of P. aeruginosa to invade tissue by breaking down physical barriers, damaging host cells, and conferring resistance to phagocytosis and host immune defenses (7,8). Specifically, ExoS and ExoT are bifunctional effectors that have 76% homology, and both include Rho GTPase-activating (GAP) and ADP-ribosyltransferase (ADPr) activities (9). The GAP activities of ExoS and ExoT function similarly to inhibit P. aeruginosa internalization by inactivating Rho GTPases, Rho, Rac, and Cdc42, which regulate actin cytoskeleton structure (10-15). ExoS ADPr activity targets multiple specific substrates, including Ras family proteins, such as Ras, RalA, Rac1, and Rabs, to interrupt cell signaling (16-18). The substrate specificity of ExoT ADPr activity differs from that of ExoS ADPr activity and is limited to Crk-I (CT10 regulat...

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A eukaryotic-type signalling system of Pseudomonas aeruginosa contributes to oxidative stress resistance, intracellular survival and virulence

Cited by 49 publications

References 78 publications

Wavelength-normalized spectroscopic analysis of Staphylococcus aureus and Pseudomonas aeruginosa growth rates

Wavelength-normalized spectroscopic analysis of Staphylococcus aureus and Pseudomonas aeruginosa growth rates

Evolution of Pseudomonas aeruginosa Virulence as a Result of Phage Predation

Regulation of Rab5 Function during Phagocytosis of Live Pseudomonas aeruginosa in Macrophages

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