scholarly journals Identification of a Genomic Island Present in the Majority of Pathogenic Isolates of Pseudomonas aeruginosa

2001 ◽  
Vol 183 (3) ◽  
pp. 843-853 ◽  
Author(s):  
Xiaoyou Liang ◽  
Xuan-Quynh T. Pham ◽  
Maynard V. Olson ◽  
Stephen Lory
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Genomic Island ◽  
Reactive Oxygen ◽  
Selective Advantage ◽  
Dna Probe ◽  
Oxygen Species ◽  
Strain Pao1 ◽  
Wide Range ◽  
Different Strains

ABSTRACT Pseudomonas aeruginosa, a ubiquitous gram-negative bacterium, is capable of colonizing a wide range of environmental niches and can also cause serious infections in humans. In order to understand the genetic makeup of pathogenic P. aeruginosastrains, a method of differential hybridization of arrayed libraries of cloned DNA fragments was developed. An M13 library of DNA from strain X24509, isolated from a patient with a urinary tract infection, was screened using a DNA probe from P. aeruginosa strain PAO1. The genome of PAO1 has been recently sequenced and can be used as a reference for comparisons of genetic organization in different strains. M13 clones that did not react with a DNA probe from PAO1 carried X24509-specific inserts. When a similar array hybridization analysis with DNA probes from different strains was used, a set of M13 clones which carried sequences present in the majority of human P. aeruginosa isolates from a wide range of clinical sources was identified. The inserts of these clones were used to identify cosmids encompassing a contiguous 48.9-kb region of the X24509 chromosome called PAGI-1 (for “P. aeruginosa genomic island 1”). PAGI-1 is incorporated in the X24509 chromosome at a locus that shows a deletion of a 6,729-bp region present in strain PAO1. Survey of the incidence of PAGI-1 revealed that this island is present in 85% of the strains from clinical sources. Approximately half of the PAGI-1-carrying strains show the same deletion as X24509, while the remaining strains contain both the PAGI-1 sequences and the 6,729-bp PAO1 segment. Sequence analysis of PAGI-1 revealed that it contains 51 predicted open reading frames. Several of these genes encoded products with predictable function based on their sequence similarities to known genes, including insertion sequences, determinants of regulatory proteins, a number of dehydrogenase gene homologs, and two for proteins of implicated in detoxification of reactive oxygen species. It is very likely that PAGI-1 was acquired by a large number of P. aeruginosa isolates through horizontal gene transfer. The selection for its maintenance may be the consequence of expression of any one of the genes of unknown function or the genes which allowP. aeruginosa to survive under the conditions that generate reactive oxygen species. Alternatively, one or both of the transcriptional regulators encoded in PAGI-1 may control the expression of genes in the P. aeruginosa chromosome, which provides a selective advantage for strains that have acquired this genomic island.

Scavenging of reactive oxygen species by tryptophan metabolites helps Pseudomonas aeruginosa escape neutrophil killing

2014 ◽  
Vol 73 ◽  
pp. 400-410 ◽  
Author(s):  
Charlotte Genestet ◽  
Audrey Le Gouellec ◽  
Hichem Chaker ◽  
Benoit Polack ◽  
Benoit Guery ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Tryptophan Metabolites

scholarly journals Evaluation of the interaction between polymyxin B and Pseudomonas aeruginosa biofilm and planktonic cells: reactive oxygen species induction and zeta potential

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Marlucy Rodrigues Lima ◽  
Gabriella Freitas Ferreira ◽  
Wallace Ribeiro Nunes Neto ◽  
Joveliane de Melo Monteiro ◽  
Áquila Rodrigues Costa Santos ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Zeta Potential ◽  
Reactive Oxygen ◽  
Polymyxin B ◽  
Oxygen Species ◽  
Planktonic Cells

scholarly journals Enhanced astaxanthin production by oxidative stress using methyl viologen as a reactive oxygen species (ROS) reagent in green microalgae Coelastrum sp.

2020 ◽  
Vol 25 (2) ◽  
pp. 95
Author(s):  
Ameerah Tharek ◽  
Shaza Eva Mohamad ◽  
Koji Iwamoto ◽  
Iwane Suzuki ◽  
Hirofumi Hara ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Methyl Viologen ◽  
Antioxidant Properties ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Green Microalgae ◽  
Wide Range ◽  
Astaxanthin Production ◽  
Potential Resource ◽  
Valuable Compounds

Microalgae are known to be a potential resource of high-value metabolites that can be used in the growing field of biotechnology. These metabolites constitute valuable compounds with a wide range of applications that strongly enhance a bio-based economy. Among these metabolites, astaxanthin is considered the most important secondary metabolite, having superior antioxidant properties. For commercial feasibility, microalgae with enhanced astaxanthin production need to be developed. In this study, the tropical green microalgae strain, Coelastrum sp., isolated from the environment in Malaysia, was incubated with methyl viologen, a reactive oxygen species (ROS) reagent that generates superoxide anion radicals (O2-) as an enhancer to improve the accumulation of astaxanthin. The effect of different concentrations of methyl viologen on astaxanthin accumulation was investigated. The results suggested that the supplementation of methyl viologen at low concentration (0.001 mM) was successfully used as a ROS reagent in facilitating and thereby increasing the production of astaxanthin in Coelastrum sp. at a rate 1.3 times higher than in the control.

scholarly journals Antibiotic Korormicin A Kills Bacteria by Producing Reactive Oxygen Species

2019 ◽  
Vol 201 (11) ◽  
Author(s):  
Adam Maynard ◽  
Nicole L. Butler ◽  
Takeshi Ito ◽  
Adilson José da Silva ◽  
Masatoshi Murai ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Reactive Oxygen ◽  
Direct Result ◽  
Oxygen Species ◽  
Gram Negative ◽  
Content Type ◽  
Nadh:Quinone Oxidoreductase

ABSTRACT Korormicin is an antibiotic produced by some pseudoalteromonads which selectively kills Gram-negative bacteria that express the Na+-pumping NADH:quinone oxidoreductase (Na+-NQR.) We show that although korormicin is an inhibitor of Na+-NQR, the antibiotic action is not a direct result of inhibiting enzyme activity. Instead, perturbation of electron transfer inside the enzyme promotes a reaction between O2 and one or more redox cofactors in the enzyme (likely the flavin adenine dinucleotide [FAD] and 2Fe-2S center), leading to the production of reactive oxygen species (ROS). All Pseudoalteromonas contain the nqr operon in their genomes, including Pseudoalteromonas strain J010, which produces korormicin. We present activity data indicating that this strain expresses an active Na+-NQR and that this enzyme is not susceptible to korormicin inhibition. On the basis of our DNA sequence data, we show that the Na+-NQR of Pseudoalteromonas J010 carries an amino acid substitution (NqrB-G141A; Vibrio cholerae numbering) that in other Na+-NQRs confers resistance against korormicin. This is likely the reason that a functional Na+-NQR is able to exist in a bacterium that produces a compound that typically inhibits this enzyme and causes cell death. Korormicin is an effective antibiotic against such pathogens as Vibrio cholerae, Aliivibrio fischeri, and Pseudomonas aeruginosa but has no effect on Bacteroides fragilis and Bacteroides thetaiotaomicron, microorganisms that are important members of the human intestinal microflora. IMPORTANCE As multidrug antibiotic resistance in pathogenic bacteria continues to rise, there is a critical need for novel antimicrobial agents. An essential requirement for a useful antibiotic is that it selectively targets bacteria without significant effects on the eukaryotic hosts. Korormicin is an excellent candidate in this respect because it targets a unique respiratory enzyme found only in prokaryotes, the Na+-pumping NADH:quinone oxidoreductase (Na+-NQR). Korormicin is synthesized by some species of the marine bacterium Pseudoalteromonas and is a potent and specific inhibitor of Na+-NQR, an enzyme that is essential for the survival and proliferation of many Gram-negative human pathogens, including Vibrio cholerae and Pseudomonas aeruginosa, among others. Here, we identified how korormicin selectively kills these bacteria. The binding of korormicin to Na+-NQR promotes the formation of reactive oxygen species generated by the reaction of the FAD and the 2Fe-2S center cofactors with O2.

scholarly journals Conditional quorum-sensing induction of a cyanide-insensitive terminal oxidase stabilizes cooperating populations of Pseudomonas aeruginosa

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Huicong Yan ◽  
Kyle L. Asfahl ◽  
Na Li ◽  
Feng Sun ◽  
Junwei Xiao ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Hydrogen Cyanide ◽  
Reactive Oxygen ◽  
Regulatory System ◽  
Metabolic Cost ◽  
Opportunistic Pathogen ◽  
Terminal Oxidase ◽  
Oxygen Species

Abstract Pseudomonas aeruginosa, an opportunistic pathogen of humans, uses quorum sensing (QS) to regulate the production of extracellular products that can benefit all members of the population. P. aeruginosa can police QS-deficient cheaters by producing hydrogen cyanide, which is also QS regulated; however, the mechanism by which cooperators selectively protect themselves from the toxicity of cyanide remained unresolved. Here, we show that a cyanide-insensitive terminal oxidase encoded by cioAB provides resistance to cyanide, but only in QS-proficient strains. QS-deficient cheaters do not activate cioAB transcription. QS-mediated regulation of cioAB expression depends on production of both cyanide by cooperators (which is QS regulated) and reactive oxygen species (ROS) from cheaters (which is not QS regulated). This type of regulatory system allows cooperating populations to respond, via ROS, to the presence of cheaters, and might allow them to defer the substantial metabolic cost of policing until cheaters are present in the population.

scholarly journals Reactive oxygen species as universal constraints in life-history evolution

2009 ◽  
Vol 276 (1663) ◽  
pp. 1737-1745 ◽  
Author(s):  
Damian K. Dowling ◽  
Leigh W. Simmons
Keyword(s):  
Reactive Oxygen Species ◽  
Life History ◽  
Evolutionary Biology ◽  
Sperm Quality ◽  
Reactive Oxygen ◽  
Life History Evolution ◽  
Oxygen Species ◽  
Trade Offs ◽  
Wide Range ◽  
History Evolution

Evolutionary theory is firmly grounded on the existence of trade-offs between life-history traits, and recent interest has centred on the physiological mechanisms underlying such trade-offs. Several branches of evolutionary biology, particularly those focusing on ageing, immunological and sexual selection theory, have implicated reactive oxygen species (ROS) as profound evolutionary players. ROS are a highly reactive group of oxygen-containing molecules, generated as common by-products of vital oxidative enzyme complexes. Both animals and plants appear to intentionally harness ROS for use as molecular messengers to fulfil a wide range of essential biological processes. However, at high levels, ROS are known to exert very damaging effects through oxidative stress. For these reasons, ROS have been suggested to be important mediators of the cost of reproduction, and of trade-offs between metabolic rate and lifespan, and between immunity, sexual ornamentation and sperm quality. In this review, we integrate the above suggestions into one life-history framework, and review the evidence in support of the contention that ROS production will constitute a primary and universal constraint in life-history evolution.

The Involvement of Reactive Oxygen Species in Polyploidization of the M-07e Human Megakaryocytic Cell Line.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4300-4300
Author(s):  
Serge Côté ◽  
Nathalie Dussault ◽  
Carl Simard
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Line ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Oxygen Species ◽  
Botulin Toxin ◽  
Cellular Processes ◽  
Intracellular Ros ◽  
Wide Range ◽  
Megakaryocytic Cell

Abstract Hematopoietic cells mature in the bone marrow under the control of a diversity of growth factors and the influence of various cell types producing superoxide and other reactive oxygen species (ROS). As ROS may regulate activities of redox-sensitive enzymes implicated in a wide range of cellular processes, we have exposed the human megakaryocytic cell line M-07e to hydrogen peroxide (H2O2) at concentrations that increased intracellular ROS and examined whether expression of the megakaryocytic programme could be enhanced. The growth-factor dependent M-07e cells display surface markers characteristic of both early myeloid progenitors and more committed members of the magakaryocyte (Mk) lineage, such as glycoproteins GPIIb-IIIa (CD41) and GPIb (CD42). H2O2 significantly reduced cell proliferation without affecting viability. After 4 days of exposure to this reagent, expression of the early Mk marker CD41 was 1.2 times higher than that of control cells. Although no change in the expression of the late Mk marker CD42 was detected, exposure to H2O2 was found to increase the incidence of multinucleate cells, polyploidy and abnormal microtubule organising centre numbers. Investigation of this phenomenon on synchronized M-07e cells revealed that H2O2 arrested cytokinesis at a late stage and that some nuclei were still able to incorporate bromodeoxyuridine (BrdU). Cell division was similarly impaired when M-07e cells were either exposed to botulin toxin C3 transferase or Y-27362 inhibitor, suggesting that H2O2 treatments affected members of the Rho family of small GTP-binding proteins and/or their effectors. Together, these findings indicate that endoreplication in Mk may be linked to changes in the cellular redox state of these cells and support the concept that differentiation and polyploidization are independently regulated events.

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