scholarly journals Involvement of Nitric Oxide in Biofilm Dispersal of Pseudomonas aeruginosa

2006 ◽  
Vol 188 (21) ◽  
pp. 7344-7353 ◽  
Author(s):  
Nicolas Barraud ◽  
Daniel J. Hassett ◽  
Sung-Hei Hwang ◽  
Scott A. Rice ◽  
Staffan Kjelleberg ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Nitrosative Stress ◽  
Sodium Dodecyl ◽  
Anaerobic Respiration ◽  
Opportunistic Pathogen ◽  
No Donor ◽  
Biofilm Dispersal ◽  
Novel Strategy

ABSTRACT Bacterial biofilms at times undergo regulated and coordinated dispersal events where sessile biofilm cells convert to free-swimming, planktonic bacteria. In the opportunistic pathogen Pseudomonas aeruginosa, we previously observed that dispersal occurs concurrently with three interrelated processes within mature biofilms: (i) production of oxidative or nitrosative stress-inducing molecules inside biofilm structures, (ii) bacteriophage induction, and (iii) cell lysis. Here we examine whether specific reactive oxygen or nitrogen intermediates play a role in cell dispersal from P. aeruginosa biofilms. We demonstrate the involvement of anaerobic respiration processes in P. aeruginosa biofilm dispersal and show that nitric oxide (NO), used widely as a signaling molecule in biological systems, causes dispersal of P. aeruginosa biofilm bacteria. Dispersal was induced with low, sublethal concentrations (25 to 500 nM) of the NO donor sodium nitroprusside (SNP). Moreover, a P. aeruginosa mutant lacking the only enzyme capable of generating metabolic NO through anaerobic respiration (nitrite reductase, ΔnirS) did not disperse, whereas a NO reductase mutant (ΔnorCB) exhibited greatly enhanced dispersal. Strategies to induce biofilm dispersal are of interest due to their potential to prevent biofilms and biofilm-related infections. We observed that exposure to SNP (500 nM) greatly enhanced the efficacy of antimicrobial compounds (tobramycin, hydrogen peroxide, and sodium dodecyl sulfate) in the removal of established P. aeruginosa biofilms from a glass surface. Combined exposure to both NO and antimicrobial agents may therefore offer a novel strategy to control preestablished, persistent P. aeruginosa biofilms and biofilm-related infections.

scholarly journals Nitric Oxide Signaling in Pseudomonas aeruginosa Biofilms Mediates Phosphodiesterase Activity, Decreased Cyclic Di-GMP Levels, and Enhanced Dispersal

2009 ◽  
Vol 191 (23) ◽  
pp. 7333-7342 ◽  
Author(s):  
Nicolas Barraud ◽  
David Schleheck ◽  
Janosch Klebensberger ◽  
Jeremy S. Webb ◽  
Daniel J. Hassett ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Opportunistic Pathogen ◽  
Site Directed Mutagenesis ◽  
Nitric Oxide Signaling ◽  
Physiological Characterization ◽  
Secondary Messenger ◽  
Increase Cell Motility ◽  
Biofilm Dispersal ◽  
Gene Expression Studies

ABSTRACT Bacteria in biofilms often undergo active dispersal events and revert to a free-swimming, planktonic state to complete the biofilm life cycle. The signaling molecule nitric oxide (NO) was previously found to trigger biofilm dispersal in the opportunistic pathogen Pseudomonas aeruginosa at low, nontoxic concentrations (N. Barraud, D. J. Hassett, S. H. Hwang, S. A. Rice, S. Kjelleberg, and J. S. Webb, J. Bacteriol. 188:7344-7353, 2006). NO was further shown to increase cell motility and susceptibility to antimicrobials. Recently, numerous studies revealed that increased degradation of the secondary messenger cyclic di-GMP (c-di-GMP) by specific phosphodiesterases (PDEs) triggers a planktonic mode of growth in eubacteria. In this study, the potential link between NO and c-di-GMP signaling was investigated by performing (i) PDE inhibitor studies, (ii) enzymatic assays to measure PDE activity, and (iii) direct quantification of intracellular c-di-GMP levels. The results suggest a role for c-di-GMP signaling in triggering the biofilm dispersal event induced by NO, as dispersal requires PDE activity and addition of NO stimulates PDE and induces the concomitant decrease in intracellular c-di-GMP levels in P. aeruginosa. Furthermore, gene expression studies indicated global responses to low, nontoxic levels of NO in P. aeruginosa biofilms, including upregulation of genes involved in motility and energy metabolism and downregulation of adhesins and virulence factors. Finally, site-directed mutagenesis of candidate genes and physiological characterization of the corresponding mutant strains uncovered that the chemotaxis transducer BdlA is involved in the biofilm dispersal response induced by NO.

Functional gold nanoparticles for the storage and controlled release of nitric oxide: applications in biofilm dispersal and intracellular delivery

2014 ◽  
Vol 2 (31) ◽  
pp. 5003-5011 ◽  
Author(s):  
Hien T. T. Duong ◽  
Nik Nik M. Adnan ◽  
Nicolas Barraud ◽  
Johan S. Basuki ◽  
Samuel K. Kutty ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Gold Nanoparticles ◽  
Controlled Release ◽  
Intracellular Delivery ◽  
Functional Polymers ◽  
No Donor ◽  
Biofilm Dispersal

Gold nanoparticles (size 10 nm) were designed to store and release nitric oxide (NO), by functionalizing their surfaces with functional polymers modified with NO-donor molecules.

scholarly journals Comprehensive Analyses of Nitric Oxide-Induced Plant Stem Cell-Related Genes in Arabidopsis thaliana

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 190
Author(s):  
Muhammad Shahid ◽  
Qari Imran ◽  
Adil Hussain ◽  
Murtaza Khan ◽  
Sang Lee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Stem Cell ◽  
Nitrosative Stress ◽  
High Reliability ◽  
Pearson Correlation ◽  
Early Time ◽  
Rna Seq ◽  
No Donor ◽  
Cis Acting ◽  
Plant Stem

Plant stem cells are pluripotent cells that have diverse applications in regenerative biology and medicine. However, their roles in plant growth and disease resistance are often overlooked. Using high-throughput RNA-seq data, we identified approximately 20 stem cell-related differentially expressed genes (DEGs) that were responsive to the nitric oxide (NO) donor S-nitrosocysteine (CySNO) after six hours of infiltration. Among these DEGs, the highest number of positive correlations (R ≥ 0.8) was observed for CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) 12. Gene ontology (GO) terms for molecular function showed DEGs associated with signal transduction and receptor activity. A promoter study of these DEGs showed the presence of cis-acting elements that are involved in growth as well as the regulation of abiotic and biotic stress. Phylogenetic analysis of the Arabidopsis stem cell-related genes and their common orthologs in rice, soybean, poplar, and tomato suggested that most soybean stem cell-related genes were grouped with the Arabidopsis CLE type of stem cell genes, while the rice stem cell-related genes were grouped with the Arabidopsis receptor-like proteins. The functional genomic-based characterization of the role of stem cell DEGs showed that under control conditions, the clv1 mutant showed a similar phenotype to that of the wild-type (WT) plants; however, under CySNO-mediated nitrosative stress, clv1 showed increased shoot and root length compared to WT. Furthermore, the inoculation of clv1 with virulent Pst DC3000 showed a resistant phenotype with fewer pathogens growing at early time points. The qRT-PCR validation and correlation with the RNA-seq data showed a Pearson correlation coefficient of >0.8, indicating the significantly high reliability of the RNA-seq analysis.

scholarly journals Differential regulation of metabolism by nitric oxide andS-nitrosothiols in endothelial cells

2011 ◽  
Vol 301 (3) ◽  
pp. H803-H812 ◽  
Author(s):  
Anne R. Diers ◽  
Katarzyna A. Broniowska ◽  
Victor M. Darley-Usmar ◽  
Neil Hogg
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Oxidative Phosphorylation ◽  
Metabolic Pathways ◽  
Nitrosative Stress ◽  
Surrogate Marker ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
No Donor

S-nitrosation of thiols in key proteins in cell signaling pathways is thought to be an important contributor to nitric oxide (NO)-dependent control of vascular (patho)physiology. Multiple metabolic enzymes are targets of both NO and S-nitrosation, including those involved in glycolysis and oxidative phosphorylation. Thus it is important to understand how these metabolic pathways are integrated by NO-dependent mechanisms. Here, we compared the effects of NO and S-nitrosation on both glycolysis and oxidative phosphorylation in bovine aortic endothelial cells using extracellular flux technology to determine common and unique points of regulation. The compound S-nitroso-l-cysteine (l-CysNO) was used to initiate intracellular S-nitrosation since it is transported into cells and results in stable S-nitrosation in vitro. Its effects were compared with the NO donor DetaNONOate (DetaNO). DetaNO treatment caused only a decrease in the reserve respiratory capacity; however, l-CysNO impaired both this parameter and basal respiration in a concentration-dependent manner. In addition, DetaNO stimulated extracellular acidification rate (ECAR), a surrogate marker of glycolysis, whereas l-CysNO stimulated ECAR at low concentrations and inhibited it at higher concentrations. Moreover, a temporal relationship between NO- and S-nitrosation-mediated effects on metabolism was identified, whereby NO caused a rapid impairment in mitochondrial function, which was eventually overwhelmed by S-nitrosation-dependent processes. Taken together, these results suggest that severe pharmacological nitrosative stress may differentially regulate metabolic pathways through both intracellular S-nitrosation and NO-dependent mechanisms. Moreover, these data provide insight into the role of NO and related compounds in vascular (patho)physiology.

scholarly journals Differences in nitric oxide steady states between arginine, hypoxanthine, uracil auxotrophs (AHU) and non-AHU strains ofNeisseria gonorrhoeaeduring anaerobic respiration in the presence of nitrite

2008 ◽  
Vol 54 (8) ◽  
pp. 639-646 ◽  
Author(s):  
Kenneth Barth ◽  
Virginia L. Clark
Keyword(s):  
Nitric Oxide ◽  
Steady State ◽  
Nitrite Reductase ◽  
Anaerobic Respiration ◽  
State Level ◽  
Cell Number ◽  
Steady State Level ◽  
No Donor ◽  
Membrane Function ◽  
Uracil Auxotrophs

Neisseria gonorrhoeae can grow by anaerobic respiration using nitrite as an alternative electron acceptor. Under these growth conditions, N. gonorrhoeae produces and degrades nitric oxide (NO), an important host defense molecule. Laboratory strain F62 has been shown to establish and maintain a NO steady-state level that is a function of the nitrite reductase/NO reductase ratio and is independent of cell number. The nitrite reductase activities (122–197 nmol NO2reduced·min–1·OD600–1) and NO reductase activities (88–155 nmol NO reduced·min–1·OD600–1) in a variety of gonococcal clinical isolates were similar to the specific activities seen in F62 (241 nmol NO2reduced·min–1·OD600–1and 88 nmol NO reduced·min–1·OD600–1, respectively). In seven gonococcal strains, the NO steady-state levels established in the presence of nitrite were similar to that of F62 (801–2121 nmol·L–1NO), while six of the strains, identified as arginine, hypoxanthine, and uracil auxotrophs (AHU), that cause asymptomatic infection in men had either two- to threefold (373–579 nmol·L–1NO) or about 100-fold (13–24 nmol·L–1NO) lower NO steady-state concentrations. All tested strains in the presence of a NO donor, 2,2′-(hydroxynitrosohydrazono)bis-ethanimine/NO, quickly lowered and maintained NO levels in the noninflammatory range of NO (<300 nmol·L–1). The generation of a NO steady-state concentration was directly affected by alterations in respiratory control in both F62 and an AHU strain, although differences in membrane function are suspected to be responsible for NO steady-state level differences in AHU strains.

scholarly journals Nitric Oxide in Chemostat-Cultured Escherichia coli Is Sensed by Fnr and Other Global Regulators: Unaltered Methionine Biosynthesis Indicates Lack of S Nitrosation

2006 ◽  
Vol 189 (5) ◽  
pp. 1845-1855 ◽  
Author(s):  
Steven T. Pullan ◽  
Mark D. Gidley ◽  
Richard A. Jones ◽  
Jason Barrett ◽  
Tania M. Stevanin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Nitrosative Stress ◽  
Adaptive Responses ◽  
Methionine Biosynthesis ◽  
Transcriptional Responses ◽  
No Donor ◽  
Global Regulators ◽  
E Coli ◽  
Cellular Effects

ABSTRACT We previously elucidated the global transcriptional responses of Escherichia coli to the nitrosating agent S-nitrosoglutathione (GSNO) in both aerobic and anaerobic chemostats, demonstrated the expression of nitric oxide (NO)-protective mechanisms, and obtained evidence of critical thiol nitrosation. The present study was the first to examine the transcriptome of NO-exposed E. coli in a chemostat. Using identical conditions, we compared the GSNO stimulon with the stimulon of NO released from two NO donor compounds {3-[2-hydroxy-1-(1-methyl-ethyl)-2-nitrosohydrazino]-1-propanamine (NOC-5) and 3-(2-hydroxy-1-methyl-2-nitrosohydrazino)-N-methyl-1-propanamine (NOC-7)} simultaneously and demonstrated that there were marked differences in the transcriptional responses to these distinct nitrosative stresses. Exposure to NO did not induce met genes, suggesting that, unlike GSNO, NO does not elicit homocysteine S nitrosation and compensatory increases in methionine biosynthesis. After entry into cells, exogenous methionine provided protection from GSNO-mediated killing but not from NO-mediated killing. Anaerobic exposure to NO led to up-regulation of multiple Fnr-repressed genes and down-regulation of Fnr-activated genes, including nrfA, which encodes cytochrome c nitrite reductase, providing strong evidence that there is NO inactivation of Fnr. Other global regulators apparently affected by NO were IscR, Fur, SoxR, NsrR, and NorR. We tried to identify components of the NorR regulon by performing a microarray comparison of NO-exposed wild-type and norR mutant strains; only norVW, encoding the NO-detoxifying flavorubredoxin and its cognate reductase, were unambiguously identified. Mutation of norV or norR had no effect on E. coli survival in mouse macrophages. Thus, GSNO (a nitrosating agent) and NO have distinct cellular effects; NO more effectively interacts with global regulators that mediate adaptive responses to nitrosative stress but does not affect methionine requirements arising from homocysteine nitrosation.

scholarly journals Detection of the Antiseptic Resistance Gene among Pseudomonas aeruginosa Isolates

2021 ◽  
pp. 75-82
Author(s):  
اخلاص نعمة
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Susceptibility ◽  
Antimicrobial Agents ◽  
Opportunistic Pathogen ◽  
Susceptibility Test ◽  
Diffusion Method ◽  
Bacterial Isolates ◽  
Disk Diffusion Method ◽  
Antibiotic Susceptibility Test ◽  
Antibiotics Susceptibility

Pseudomonas aeruginosa is an opportunistic pathogen that causes a number of infections in immunocompromised patients. This organism appears to improve resistance  to many antimicrobial agents and a high percentage of clinical isolates of P. aeruginosa exhibit multidrug resistance (MDR) phenotype . The purpose of this study is to screen the antibiotic susceptibility patterns and the prevalence of qacE delta1 gene among bacterial isolates. Accordingly, 145 samples were collected from different clinical sources from patients who admitted to different hospitals in Baghdad city in a period ranged 23/8/2018-1/1/2019. The isolates were diagnosed as P. aeruginosa based on routine bacteriological methods and confirmed by a molecular method using 16SrRNA gene. The antibiotic  susceptibility test was performed to all identified isolates by Kirby-Bauer Disk Diffusion method using ten  types of antibiotics. The results of antibiotics susceptibility test revealed high levels of resistance toward Piperacillin (72.22%), Trimethoprim (68%), Ceftazidime (68%), Colistin (40.28%), and Levofloxacin (33.33%). And , the minimum inhibitory concentration (MIC) of Cetrimide was tested using different concentrations (2.048 to 0.004µg/100µl) and the results showed that MIC values ranged between 2.048 and 0.016) μg/100μL, and  the concentration of  0.256 μg/100μl was more frequent . Finally, the prevalence of qacE delta1 gene among bacterial isolates was detected in percentage  63.88% among bacterial isolates .

scholarly journals Structure of heme d 1-free cd 1 nitrite reductase NirS

2020 ◽  
Vol 76 (6) ◽  
pp. 250-256
Author(s):  
Thomas Klünemann ◽  
Wulf Blankenfeldt
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Active Site ◽  
Opportunistic Pathogen ◽  
Active Enzyme ◽  
Free Form ◽  
Nitrate Respiration ◽  
Gram Negative ◽  
Open Conformation

A key step in anaerobic nitrate respiration is the reduction of nitrite to nitric oxide, which is catalysed by the cd 1 nitrite reductase NirS in, for example, the Gram-negative opportunistic pathogen Pseudomonas aeruginosa. Each subunit of this homodimeric enzyme consists of a cytochrome c domain and an eight-bladed β-propeller that binds the uncommon isobacteriochlorin heme d 1 as an essential part of its active site. Although NirS has been well studied mechanistically and structurally, the focus of previous studies has been on the active heme d 1-bound form. The heme d 1-free form of NirS reported here, which represents a premature state of the reductase, adopts an open conformation with the cytochrome c domains moved away from each other with respect to the active enzyme. Further, the movement of a loop around Trp498 seems to be related to a widening of the propeller, allowing easier access to the heme d 1-binding side. Finally, a possible link between the open conformation of NirS and flagella formation in P. aeruginosa is discussed.

scholarly journals CTA4 Transcription Factor Mediates Induction of Nitrosative Stress Response in Candida albicans

2007 ◽  
Vol 7 (2) ◽  
pp. 268-278 ◽  
Author(s):  
Wiriya Chiranand ◽  
Ian McLeod ◽  
Huaijin Zhou ◽  
Jed J. Lynn ◽  
Luis A. Vega ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Magnetic Beads ◽  
Nitrosative Stress ◽  
Regulatory Region ◽  
Regulatory Elements ◽  
Host Immune System ◽  
No Donor ◽  
Cell Extracts

ABSTRACT This work has identified regulatory elements in the major fungal pathogen Candida albicans that enable response to nitrosative stress. Nitric oxide (NO) is generated by macrophages of the host immune system and commensal bacteria, and the ability to resist its toxicity is one adaptation that promotes survival of C. albicans inside the human body. Exposing C. albicans to NO induces upregulation of the flavohemoglobin Yhb1p. This protein confers protection by enzymatically converting NO to harmless nitrate, but it is unknown how C. albicans is able to detect NO in its environment and thus initiate this defense only as needed. We analyzed this problem by incrementally mutating the YHB1 regulatory region to identify a nitric oxide-responsive element (NORE) that is required for NO sensitivity. Five transcription factor candidates of the Zn(II)2-Cys6 family were then isolated from crude whole-cell extracts by using magnetic beads coated with this DNA element. Of the five, only deletion of the CTA4 gene prevented induction of YHB1 transcription during nitrosative stress and caused growth sensitivity to the NO donor dipropylenetriamine NONOate; Cta4p associates in vivo with NORE DNA from the YHB1 regulatory region. Deletion of CTA4 caused a small but significant decrease in virulence. A CTA4-dependent putative sulfite transporter encoded by SSU1 is also implicated in NO response, but C. albicans ssu1 mutants were not sensitive to NO, in contrast to findings in Saccharomyces cerevisiae. Cta4p is the first protein found to be necessary for initiating NO response in C. albicans.

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