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Sample records for aeruginosa lipopolysaccharide expression

  1. Lipopolysaccharides of the cyanobacterium Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Raziuddin, S.; Siegelman, H.W.; Tornabene, T.G.

    1983-01-01

    Lipopolysaccharides (LPS) of two isolates of Microcystis aeruginosa were extracted with phenol/water and purified. Cesium chloride gradient ultracentrifugation of these preparations yielded only one fraction. The LPS contained significant amounts of 3-deoxy-D-manno-octulosonic acid, glucose, 3-deoxy sugars, glucosamine, fatty acids, fatty acid esters, hexoses, and phosphate. Heptose, a characteristic sugar component of the polysaccharide moiety of LPS of most gram-negative bacteria was absent. Lipopolysaccharides and lipid A hydrolysate of LPS preparations were active in mouse lethality and Limulus lysate gelation. The lipid A moiety was slightly less active in toxicity and Limulus lysate gelation assay than the intact LPS. The LPS and lipid A moiety of the two isolates of M. aeruginosa were less active in toxicity in mice and Limulus test than LPS of Salmonella abortus equi. 37 references, 1 figure, 3 tables.

  2. Pseudomonas aeruginosa lipopolysaccharide induces CF-like alteration of protein secretion by human tracheal gland cells.

    Science.gov (United States)

    Kammouni, W; Figarella, C; Baeza, N; Marchand, S; Merten, M D

    1997-12-18

    Human tracheal gland (HTG) serous cells are now believed to play a major role in the physiopathology of cystic fibrosis. Because of the persistent inflammation and the specific infection by Pseudomonas aeruginosa in the lung, we looked for the action of the lipopolysaccharide (LPS) of this bacteria on human tracheal gland cells in culture by studying the secretion of the secretory leukocyte proteinase inhibitor (SLPI) which is a specific serous secretory marker of these cells. Treatment with Pseudomonas aeruginosa LPS resulted in a significant dose-dependent increase in the basal production of SLPI (+ 250 +/- 25%) whilst the SLPI transcript mRNA levels remained unchanged. This LPS-induced increase in secretion was inhibited by glucocorticoides. Furthermore, LPS treatment of HTG cells induces a loss of responsiveness to carbachol and isoproterenol but not to adenosine triphosphate. These findings indicate that HTG cells treated by Pseudomonas aeruginosa LPS have the same behavior as those previously observed with CF-HTG cells. Exploration by using reverse transcriptase polymerase chain reaction amplification showed that LPS downregulated cystic fibrosis transmembrane conductance regulator (CFTR) mRNA expression in HTG cells indicative of a link between CFTR function and consequent CF-like alteration in protein secretory process.

  3. Lipopolysaccharide Antigens of Pseudomonas aeruginosa and Design of Novel Vaccines.

    Science.gov (United States)

    1987-09-01

    Studies on the Lipopolysaccharide Antigens of Seven Immunotypes of P a_ n , SELAQ, Proc. 3 VL Seminario Latinoamericano J1 Quimica , pp. 143-159 (1979). 7...Bioolymers, 19 (1980) 1801-1814. 74" , 8. Derek Horton and David A. Riley, Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy of Lipopolysaccharides...Amer. Chem. Soc., 87 (1965), 1345-1353. 40. D. Horton and D. A. Riley, "Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy of Lipopolysaccharides

  4. Lipopolysaccharide Membranes and Membrane Proteins of Pseudomonas aeruginosa Studied by Computer Simulation

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    Straatsma, TP

    2006-12-01

    Pseudomonas aeruginosa is a ubiquitous environmental Gram-negative bacterium with high metabolic versatility and an exceptional ability to adapt to a wide range of ecological environments, including soil, marches, coastal habitats, plant and animal tissues. Gram-negative microbes are characterized by the asymmetric lipopolysaccharide outer membrane, the study of which is important for a number of applications. The adhesion to mineral surfaces plays a central role in characterizing their contribution to the fate of contaminants in complex environmental systems by effecting microbial transport through soils, respiration redox chemistry, and ion mobility. Another important application stems from the fact that it is also a major opportunistic human pathogen that can result in life-threatening infections in many immunocompromised patients, such as lung infections in children with cystic fibrosis, bacteraemia in burn victims, urinary-tract infections in catheterized patients, hospital-acquired pneumonia in patients on respirators, infections in cancer patients receiving chemotherapy, and keratitis and corneal ulcers in users of extended-wear soft contact lenses. The inherent resistance against antibiotics which has been linked with the specific interactions in the outer membrane of P. aeruginosa makes these infections difficult to treat. Developments in simulation methodologies as well as computer hardware have enabled the molecular simulation of biological systems of increasing size and with increasing accuracy, providing detail that is difficult or impossible to obtain experimentally. Computer simulation studies contribute to our understanding of the behavior of proteins, protein-protein and protein-DNA complexes. In recent years, a number of research groups have made significant progress in applying these methods to the study of biological membranes. However, these applications have been focused exclusively on lipid bilayer membranes and on membrane proteins in lipid

  5. Computer simulation of uranyl uptake by the rough lipopolysaccharide membrane of Pseudomonas aeruginosa.

    Science.gov (United States)

    Lins, Roberto D; Vorpagel, Erich R; Guglielmi, Matteo; Straatsma, T P

    2008-01-01

    Heavy metal environmental contaminants cannot be destroyed but require containment, preferably in concentrated form, in a solid or immobile form for recycling or final disposal. Microorganisms are able to take up and deposit high levels of contaminant metals, including radioactive metals such as uranium and plutonium, into their cell wall. Consequently, these microbial systems are of great interest as the basis for potential environmental bioremediation technologies. The outer membranes of Gram-negative microbes are highly nonsymmetric and exhibit a significant electrostatic potential gradient across the membrane. This gradient has a significant effect on the uptake and transport of charged and dipolar compounds. However, the effectiveness of microbial systems for environmental remediation will depend strongly on specific properties that determine the uptake of targeted contaminants by a particular cell wall. To aid in the design of microbial remediation technologies, knowledge of the factors that determine the affinity of a particular bacterial outer membrane for the most common ionic species found in contaminated soils and groundwater is of great importance. Using our previously developed model for the lipopolysaccharide (LPS) membrane of Pseudomonas aeruginosa, this work presents the potentials of mean force as the estimate of the free energy profile for uptake of sodium, calcium, chloride, uranyl ions, and a water molecule by the bacterial LPS membrane. A compatible classical parameter set for uranyl has been developed and validated. Results show that the uptake of uranyl is energetically a favorable process relative to the other ions studied. At neutral pH, this nuclide is shown to be retained on the surface of the LPS membrane through chelation with the carboxyl and hydroxyl groups located in the outer core.

  6. Gene expression in Pseudomonas aeruginosa swarming motility

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    Déziel Eric

    2010-10-01

    Full Text Available Abstract Background The bacterium Pseudomonas aeruginosa is capable of three types of motilities: swimming, twitching and swarming. The latter is characterized by a fast and coordinated group movement over a semi-solid surface resulting from intercellular interactions and morphological differentiation. A striking feature of swarming motility is the complex fractal-like patterns displayed by migrating bacteria while they move away from their inoculation point. This type of group behaviour is still poorly understood and its characterization provides important information on bacterial structured communities such as biofilms. Using GeneChip® Affymetrix microarrays, we obtained the transcriptomic profiles of both bacterial populations located at the tip of migrating tendrils and swarm center of swarming colonies and compared these profiles to that of a bacterial control population grown on the same media but solidified to not allow swarming motility. Results Microarray raw data were corrected for background noise with the RMA algorithm and quantile normalized. Differentially expressed genes between the three conditions were selected using a threshold of 1.5 log2-fold, which gave a total of 378 selected genes (6.3% of the predicted open reading frames of strain PA14. Major shifts in gene expression patterns are observed in each growth conditions, highlighting the presence of distinct bacterial subpopulations within a swarming colony (tendril tips vs. swarm center. Unexpectedly, microarrays expression data reveal that a minority of genes are up-regulated in tendril tip populations. Among them, we found energy metabolism, ribosomal protein and transport of small molecules related genes. On the other hand, many well-known virulence factors genes were globally repressed in tendril tip cells. Swarm center cells are distinct and appear to be under oxidative and copper stress responses. Conclusions Results reported in this study show that, as opposed to

  7. Cell surface physico chemistry alters biofilm development of Pseudomonas aeruginosa lipopolysaccharide mutants

    NARCIS (Netherlands)

    Flemming, CA; Palmer, RJ; Arrage, AA; van der Mei, H.C.; White, DC

    1999-01-01

    The hydrophobic and electrostatic characteristics of bacterial cell surfaces were compared with attachment proclivity and biomass accumulation over time between wildtype Pseudomonas aeruginosa serotype O6 (possesses A and B band LPS), and three LPS-deficient mutants, vi;. A28 (A(+)B(-)), R5

  8. Antigenic polysaccharides of bacteria. 14. Structure of the O-specific polysaccharide chain of the lipopolysaccharide of pseudomonas aeruginosa O12 (Lanyi)

    International Nuclear Information System (INIS)

    Knirel', Y.A.; Shashkov, A.S.; Dmitriev, B.A.; Kochetkov, N.K.; Stanislavskii, E.S.; Mashilova, G.M.

    1986-01-01

    The mild-alkaline hydrolysis of the lipopolysaccharide of Pseudomonas aeruginosa O12 (Lanyi classification) has given the O-specific polysaccharide, which is constructed of D-ribose and N-acetyl-D-galactosamine residues. The disaccharide structure for the repeating unit of this polysaccharide has been established by a nondestructive method as the result of the complete deciphering of its 1 H and 13 C NMR spectra using homonuclear and selective heteronuclear 13 C { 1 H} double resonance

  9. Plant-expressed pyocins for control of Pseudomonas aeruginosa.

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    Šarūnas Paškevičius

    Full Text Available The emergence, persistence and spread of antibiotic-resistant human pathogenic bacteria heralds a growing global health crisis. Drug-resistant strains of gram-negative bacteria, such as Pseudomonas aeruginosa, are especially dangerous and the medical and economic burden they impose underscore the critical need for finding new antimicrobials. Recent studies have demonstrated that plant-expressed bacteriocins of the colicins family can be efficient antibacterials against all major enteropathogenic strains of E. coli. We extended our studies of colicin-like bacteriocins to pyocins, which are produced by strains of P. aeruginosa for ecological advantage against other strains of the same species. Using a plant-based transient expression system, we expressed six different pyocins, namely S5, PaeM, L1, L2, L3 and one new pyocin, PaeM4, and purified them to homogeneity. Among these pyocins, PaeM4 demonstrated the broadest spectrum of activity by controlling 53 of 100 tested clinical isolates of P. aeruginosa. The activity of plant-made pyocins was confirmed in the agar drop, liquid culture susceptibility and biofilm assays, and in the Galleria mellonella animal infection model.

  10. Lipopolysaccharide induces autotaxin expression in human monocytic THP-1 cells

    International Nuclear Information System (INIS)

    Li Song; Zhang Junjie

    2009-01-01

    Autotaxin (ATX) is a secreted enzyme with lysophospholipase D (lysoPLD) activity, which converts lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA), a bioactive phospholipid involved in numerous biological activities, including cell proliferation, differentiation, and migration. In the present study, we found that bacterial lipopolysaccharide (LPS), a well-known initiator of the inflammatory response, induced ATX expression in monocytic THP-1 cells. The activation of PKR, JNK, and p38 MAPK was required for the ATX induction. The LPS-induced ATX in THP-1 cells was characterized as the β isoform. In the presence of LPC, ATX could promote the migrations of THP-1 and Jurkat cells, which was inhibited by pertussis toxin (PTX), an inhibitor of Gi-mediated LPA receptor signaling. In summary, LPS induces ATX expression in THP-1 cells via a PKR, JNK and p38 MAPK-mediated mechanism, and the ATX induction is likely to enhance immune cell migration in proinflammatory response by regulating LPA levels in the microenvironment.

  11. Interaction of polycationic antibiotics with Pseudomonas aeruginosa lipopolysaccharide and lipid A studied by using dansyl-polymyxin.

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    Moore, R A; Bates, N C; Hancock, R E

    1986-01-01

    A fluorescent derivative of polymyxin B (dansyl-polymyxin) was used to study the interaction of polycations with lipopolysaccharide (LPS) and lipid A from Pseudomonas aeruginosa. Dansyl-polymyxin became bound to LPS and lipid A sites, including Mg2+-binding sites, resulting in a 20-fold enhancement of fluorescence. A Hill plot of the binding data showed that the binding of dansyl-polymyxin to LPS was cooperative (n = 1.98) and of high affinity (S0.5 = 0.38 microM). The maximal binding capacity of LPS was approximately four molecules of dansyl-polymyxin per mol of LPS. The dansyl-polymyxin interaction with lipid A displayed similar kinetics (n = 2.26; S0.5 = 0.38 microM), and the maximal binding capacity was approximately 2 mol of dansyl-polymyxin per mol of lipid A. A variety of polycationic compounds, including gentamicin, streptomycin, and polymyxin B, as well as Mg2+, were able to displace dansyl-polymyxin bound to LPS or to lipid A. Marked differences both in terms of the degree of displacement and in terms of the amount of competing polycation required to displace a given amount of dansyl-polymyxin were observed. Addition of excess polymyxin B resulted in displacement of all of the dansyl-polymyxin, demonstrating that only polymyxin-binding sites were being probed. Our data demonstrate that polymyxin B binds to multiple sites on LPS, including sites which bind aminoglycoside antibiotics and other polycationic compounds. PMID:3013085

  12. Recombinant Expression Screening of P. aeruginosa Bacterial Inner Membrane Proteins

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    Jeffery Constance J

    2010-11-01

    Full Text Available Abstract Background Transmembrane proteins (TM proteins make up 25% of all proteins and play key roles in many diseases and normal physiological processes. However, much less is known about their structures and molecular mechanisms than for soluble proteins. Problems in expression, solubilization, purification, and crystallization cause bottlenecks in the characterization of TM proteins. This project addressed the need for improved methods for obtaining sufficient amounts of TM proteins for determining their structures and molecular mechanisms. Results Plasmid clones were obtained that encode eighty-seven transmembrane proteins with varying physical characteristics, for example, the number of predicted transmembrane helices, molecular weight, and grand average hydrophobicity (GRAVY. All the target proteins were from P. aeruginosa, a gram negative bacterial opportunistic pathogen that causes serious lung infections in people with cystic fibrosis. The relative expression levels of the transmembrane proteins were measured under several culture growth conditions. The use of E. coli strains, a T7 promoter, and a 6-histidine C-terminal affinity tag resulted in the expression of 61 out of 87 test proteins (70%. In this study, proteins with a higher grand average hydrophobicity and more transmembrane helices were expressed less well than less hydrophobic proteins with fewer transmembrane helices. Conclusions In this study, factors related to overall hydrophobicity and the number of predicted transmembrane helices correlated with the relative expression levels of the target proteins. Identifying physical characteristics that correlate with protein expression might aid in selecting the "low hanging fruit", or proteins that can be expressed to sufficient levels using an E. coli expression system. The use of other expression strategies or host species might be needed for sufficient levels of expression of transmembrane proteins with other physical

  13. A possible mechanism of maxillofacial abscess formation: involvement of Porphyromonas endodontalis lipopolysaccharide via the expression of inflammatory cytokines.

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    Murakami, Y; Hanazawa, S; Tanaka, S; Iwahashi, H; Yamamoto, Y; Fujisawa, S

    2001-12-01

    In a previous study, we developed a specific monoclonal antibody against Porphyromonas endodontalis lipopolysaccharide, and demonstrated that this lipopolysaccharide was detected in bacterially infected root canal fluid. We suggest here that P. endodontalis lipopolysaccharide in the infectious materials plays a stimulatory role in maxillofacial abscess formation via the expression of inflammatory cytokines. Our epidemiological study showed that this lipopolysaccharide was detected in significant levels the infectious material of patients with periapical periodontitis and odontogenic abscesses. Interestingly, infectious material-induced expression of tumor necrosis factor-alpha, interleukin-1beta, or neutrophil chemoattractant KC genes in mouse macrophages, was significantly neutralized by monoclonal antibody against the lipopolysaccharide. In addition, we also detected a significant amount of tumor necrosis factor-alpha in the infectious material. These results suggest that P. endodontalis lipopolysaccharide plays an important role in the pathogenic mechanism of maxillofacial abscess formation via the expression of inflammatory cytokines.

  14. Relationship between chemical composition and biological function of Pseudomonas aeruginosa lipopolysaccharide: effect on human neutrophil chemotaxis and oxidative burst

    DEFF Research Database (Denmark)

    Kharazmi, A; Fomsgaard, A; Conrad, R S

    1991-01-01

    There are conflicting data on the effect of bacterial lipopolysaccharides (LPS) on the function of human neutrophils. The present study was designed to examine the relationship between chemical composition and the modulatory effect of LPS on human neutrophil function. LPS was extracted from five...

  15. Conjugative type IVb pilus recognizes lipopolysaccharide of recipient cells to initiate PAPI-1 pathogenicity island transfer in Pseudomonas aeruginosa

    Science.gov (United States)

    Pseudomonas aeruginosa pathogenicity island 1 (PAPI-1) is one of the largest genomic islands of this important opportunistic human pathogen. Previous studies have shown that PAPI-1 encodes several putative virulence factors, a major regulator of biofilm formation, and antibiotic-resistance traits, a...

  16. RNA interference prevents lipopolysaccharide-induced preprotachykinin gene expression

    International Nuclear Information System (INIS)

    Lai, Y.-L.; Yu, S.C.; Chen, M.-J.

    2003-01-01

    We showed previously that lipopolysaccharide (LPS) induces noncholinergic airway hyperreactivity to capsaicin via an upregulation of tachykinin synthesis. This study was designed to test whether double-stranded preprotachykinin (ds PPT) RNA, RNA interference (RNAi), prevents the LPS-induced alterations. First, cultured primary nodose ganglial cells of newborn Brown-Norway rats were divided into four groups: control; LPS; LPS+RNAi; and LPS+RNAi+liposome. Second, young Brown-Norway rats for the in vivo study were divided into three groups (control; LPS; and LPS+RNAi), and ds PPT RNA was microinjected bilaterally into the nodose ganglia in the LPS+RNAi group. Then, ganglial cells were collected from the culture whereas the nodose ganglia and lungs were sampled from the animals, and PPT mRNA and substance P (SP) levels were analyzed. Also, airway reactivity to capsaicin was performed in vivo. LPS induced significant increases in PPT mRNA and SP levels in vitro and in vivo and an increase in airway reactivity to capsaicin in vivo. However, ds PPT RNA, but not scrambled RNA, prevented all LPS-induced alterations. The effect of ds PPT RNA was not enhanced by liposome in vitro. Therefore, we demonstrated that the local application of RNAi prevents effectively the activation of the noncholinergic system modulating the lungs/airways

  17. Chemical Inhibition of Kynureninase Reduces Pseudomonas aeruginosa Quorum Sensing and Virulence Factor Expression.

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    Kasper, Stephen H; Bonocora, Richard P; Wade, Joseph T; Musah, Rabi Ann; Cady, Nathaniel C

    2016-04-15

    The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy.

  18. Serum Albumin Alters the Expression of Pseudomonas Aeruginosa Iron Controlled Genes

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    The objectives of this study were to examine the effect serum on global transcription within P. aeruginosa at different phases of growth and the role of iron in this regulation. Results presented in this study suggest a novel mechanism through which serum regulates the expression of different P. ae...

  19. Defects in rhizobial cyclic glucan and lipopolysaccharide synthesis alter legume gene expression during nodule development

    DEFF Research Database (Denmark)

    D'Antuono, Alejandra L; Ott, Thomas; Krusell, Lene

    2008-01-01

    cDNA array technology was used to compare transcriptome profiles of Lotus japonicus roots inoculated with a Mesorhizobium loti wild-type and two mutant strains affected in cyclic beta(1-2) glucan synthesis (cgs) and in lipopolysaccharide synthesis (lpsbeta2). Expression of genes associated...... with the development of a fully functional nodule was significantly affected in plants inoculated with the cgs mutant. Array results also revealed that induction of marker genes for nodule development was delayed when plants were inoculated with the lpsbeta2 mutant. Quantitative real-time reverse......-transcriptase polymerase chain reaction was used to quantify gene expression of a subset of genes involved in plant defense response, redox metabolism, or genes that encode for nodulins. The majority of the genes analyzed in this study were more highly expressed in roots inoculated with the wild type compared with those...

  20. Systemic administration of lipopolysaccharide increases the expression of aquaporin-4 in the rat anterior pituitary gland.

    Science.gov (United States)

    Kuwahara-Otani, Sachi; Maeda, Seishi; Tanaka, Koichi; Hayakawa, Tetsu; Seki, Makoto

    2013-01-01

    We investigated the effects of lipopolysaccharide (LPS)-induced endotoxemia on the expression of aquaporin-4 (AQP4) in the rat anterior pituitary gland, using the real-time polymerase chain reaction and immunohistochemistry. After intraperitoneal injection of LPS, the level of AQP4 mRNA doubled at 2, 4 and 8 hr. Immunohistochemical analysis showed an increase with time in AQP4 immunostaining in folliculo-stellate cells following LPS injection; the intensity of immunoreactivity peaked at 8 hr. At the same time, some cyst-like structures, formed by AQP4-positive cells, were observed. These findings indicate that LPS induces the expression of AQP4 in the anterior pituitary gland. The present results should provide an important key to elucidate the pathogenesis of the anterior pituitary gland during endotoxemia.

  1. Factors Affecting Catalase Expression in Pseudomonas aeruginosa Biofilms and Planktonic Cells

    OpenAIRE

    Frederick, Jesse R.; Elkins, James G.; Bollinger, Nikki; Hassett, Daniel J.; McDermott, Timothy R.

    2001-01-01

    Previous work with Pseudomonas aeruginosa showed that catalase activity in biofilms was significantly reduced relative to that in planktonic cells. To better understand biofilm physiology, we examined possible explanations for the differential expression of catalase in cells cultured in these two different conditions. For maximal catalase activity, biofilm cells required significantly more iron (25 μM as FeCl3) in the medium, whereas planktonic cultures required no addition of iron. However, ...

  2. Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

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    Lieberman AR

    2006-01-01

    Full Text Available Abstract Background Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker. Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation. Results Application of LPS induced a gradient of inflammation through the full depth of the motor cortex and promoted c-Jun and SCG10 expression for up to 2 weeks, and GAP-43 upregulation for 3 days by many corticospinal neurons, but had very limited effects on neuronal ATF3 expression. However, many glial cells in the subcortical white matter upregulated ATF3. LPS did not promote sprouting of anterogradely labelled corticospinal axons, which did not grow into or beyond a cervical lesion site. Conclusion Inflammation produced by topical application of LPS promoted increased expression of some growth-associated genes in the cell bodies of corticospinal neurons, but was insufficient to promote regeneration of the corticospinal tract.

  3. A plasmid-encoded UmuD homologue regulates expression of Pseudomonas aeruginosa SOS genes.

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    Díaz-Magaña, Amada; Alva-Murillo, Nayeli; Chávez-Moctezuma, Martha P; López-Meza, Joel E; Ramírez-Díaz, Martha I; Cervantes, Carlos

    2015-07-01

    The Pseudomonas aeruginosa plasmid pUM505 contains the umuDC operon that encodes proteins similar to error-prone repair DNA polymerase V. The umuC gene appears to be truncated and its product is probably not functional. The umuD gene, renamed umuDpR, possesses an SOS box overlapped with a Sigma factor 70 type promoter; accordingly, transcriptional fusions revealed that the umuDpR gene promoter is activated by mitomycin C. The predicted sequence of the UmuDpR protein displays 23 % identity with the Ps. aeruginosa SOS-response LexA repressor. The umuDpR gene caused increased MMC sensitivity when transferred to the Ps. aeruginosa PAO1 strain. As expected, PAO1-derived knockout lexA-  mutant PW6037 showed resistance to MMC; however, when the umuDpR gene was transferred to PW6037, MMC resistance level was reduced. These data suggested that UmuDpR represses the expression of SOS genes, as LexA does. To test whether UmuDpR exerts regulatory functions, expression of PAO1 SOS genes was evaluated by reverse transcription quantitative PCR assays in the lexA-  mutant with or without the pUC_umuD recombinant plasmid. Expression of lexA, imuA and recA genes increased 3.4-5.3 times in the lexA-  mutant, relative to transcription of the corresponding genes in the lexA+ strain, but decreased significantly in the lexA- /umuDpR transformant. These results confirmed that the UmuDpR protein is a repressor of Ps. aeruginosa SOS genes controlled by LexA. Electrophoretic mobility shift assays, however, did not show binding of UmuDpR to 5' regions of SOS genes, suggesting an indirect mechanism of regulation.

  4. Intracellular expression of toll-like receptor 4 in neuroblastoma cells and their unresponsiveness to lipopolysaccharide

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    Mori Isamu

    2006-12-01

    Full Text Available Abstract Background Recently it has been reported that, toll-like receptors (TLRs are expressed on a series of tumor cells, such as colon cancer, breast cancer, prostate cancer, melanoma and lung cancer. Although some cancer cells like melanoma cells are known to respond to lipopolysaccharide (LPS via TLR4, not all cancer cells are positive for TLR4. There is little information on the expression and function of TLR4 in neuroblastoma cells. In this study, we investigated the expression of TLR4 in human neuroblastoma NB-1 cell line. Methods Expression and localization of TLR4 were detected by reverse transcription-polymerase chain reaction (RT-PCR and flow cytometric analysis, respectively. Activation of nuclear factor (NF-κB by LPS was detected by degradation of IκB-α and NF-κB luciferase assay. Activation and expression of mitogen-activated protein (MAP kinase and interferon regulatory factor (IRF-3 was detected by immunoblot analysis. Results Human NB-1 neuroblastoma cells expressed intracellular form of TLR4, but not the cell surface form. Further, NB-1 cells express CD14, MD2 and MyD88, which are required for LPS response. However, LPS did not significantly induce NF-κB activation in NB-1 cells although it slightly degraded IκB-α. NB-1 cells expressed no IRF-3, which plays a pivotal role on the MyD88-independent pathway of LPS signaling. Collectively, NB-1 cells are capable to avoid their response to LPS. Conclusion Although human NB-1 neuroblastoma cells possessed all the molecules required for LPS response, they did not respond to LPS. It might be responsible for intracellular expression of TLR4 or lack of IRF-3.

  5. Intracellular expression of toll-like receptor 4 in neuroblastoma cells and their unresponsiveness to lipopolysaccharide

    International Nuclear Information System (INIS)

    Hassan, Ferdaus; Islam, Shamima; Tumurkhuu, Gantsetseg; Naiki, Yoshikazu; Koide, Naoki; Mori, Isamu; Yoshida, Tomoaki; Yokochi, Takashi

    2006-01-01

    Recently it has been reported that, toll-like receptors (TLRs) are expressed on a series of tumor cells, such as colon cancer, breast cancer, prostate cancer, melanoma and lung cancer. Although some cancer cells like melanoma cells are known to respond to lipopolysaccharide (LPS) via TLR4, not all cancer cells are positive for TLR4. There is little information on the expression and function of TLR4 in neuroblastoma cells. In this study, we investigated the expression of TLR4 in human neuroblastoma NB-1 cell line. Expression and localization of TLR4 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis, respectively. Activation of nuclear factor (NF)-κB by LPS was detected by degradation of IκB-α and NF-κB luciferase assay. Activation and expression of mitogen-activated protein (MAP) kinase and interferon regulatory factor (IRF)-3 was detected by immunoblot analysis. Human NB-1 neuroblastoma cells expressed intracellular form of TLR4, but not the cell surface form. Further, NB-1 cells express CD14, MD2 and MyD88, which are required for LPS response. However, LPS did not significantly induce NF-κB activation in NB-1 cells although it slightly degraded IκB-α. NB-1 cells expressed no IRF-3, which plays a pivotal role on the MyD88-independent pathway of LPS signaling. Collectively, NB-1 cells are capable to avoid their response to LPS. Although human NB-1 neuroblastoma cells possessed all the molecules required for LPS response, they did not respond to LPS. It might be responsible for intracellular expression of TLR4 or lack of IRF-3

  6. Gene expression results in lipopolysaccharide-stimulated monocytes depend significantly on the choice of reference genes

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    Øvstebø Reidun

    2010-05-01

    Full Text Available Abstract Background Gene expression in lipopolysaccharide (LPS-stimulated monocytes is mainly studied by quantitative real-time reverse transcription PCR (RT-qPCR using GAPDH (glyceraldehyde 3-phosphate dehydrogenase or ACTB (beta-actin as reference gene for normalization. Expression of traditional reference genes has been shown to vary substantially under certain conditions leading to invalid results. To investigate whether traditional reference genes are stably expressed in LPS-stimulated monocytes or if RT-qPCR results are dependent on the choice of reference genes, we have assessed and evaluated gene expression stability of twelve candidate reference genes in this model system. Results Twelve candidate reference genes were quantified by RT-qPCR in LPS-stimulated, human monocytes and evaluated using the programs geNorm, Normfinder and BestKeeper. geNorm ranked PPIB (cyclophilin B, B2M (beta-2-microglobulin and PPIA (cyclophilin A as the best combination for gene expression normalization in LPS-stimulated monocytes. Normfinder suggested TBP (TATA-box binding protein and B2M as the best combination. Compared to these combinations, normalization using GAPDH alone resulted in significantly higher changes of TNF-α (tumor necrosis factor-alpha and IL10 (interleukin 10 expression. Moreover, a significant difference in TNF-α expression between monocytes stimulated with equimolar concentrations of LPS from N. meningitides and E. coli, respectively, was identified when using the suggested combinations of reference genes for normalization, but stayed unrecognized when employing a single reference gene, ACTB or GAPDH. Conclusions Gene expression levels in LPS-stimulated monocytes based on RT-qPCR results differ significantly when normalized to a single gene or a combination of stably expressed reference genes. Proper evaluation of reference gene stabiliy is therefore mandatory before reporting RT-qPCR results in LPS-stimulated monocytes.

  7. Intracerebroventricular Injection of Lipopolysaccharide Increases Gene Expression of Connexin32 Gap Junction in Rat Hippocampus

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    Mohammad Abbasian

    2013-11-01

    Full Text Available Introduction: Gap junctions are intercellular membrane channels that provide direct cytoplasmic continuity between adjacent cells. This communication can be affected by changes in expression of gap junctional subunits called Connexins (Cx. Changes in the expression and function of connexins are associated with number of brain neurodegenerative diseases. Neuroinflammation is a hallmark of various central nervous system (CNS diseases, like multiple sclerosis, Alzheimer's disease and epilepsy. Neuroinflammation causes change in Connexins expression. Hippocampus, one of the main brain regions with a wide network of Gap junctions between different neural cell types, has particular vulnerability to damage and consequent inflammation. Cx32 – among Connexins– is expressed in hippocampal Olygodandrocytes and some neural subpopulations. Although multiple lines of evidence indicate that there is an association between neuroinflammation and the expression of connexin, the direct effect of neuroinflammation on the expression of connexins has not been well studied. In the present study, the effect of neuroinflammation induced by the Lipopolysaccharide (LPS on Cx32 gene and protein expressions in rat hippocampus is evaluated. Methods: LPS (2.5μg/rat was infused into the rat cerebral ventricles for 14 days. Cx32 mRNA and protein levels were measured by Real Time PCR and Western Blot after 1st, 7th and 14th injection of LPS in the hippocampus. Results: Significant increase in Cx32 mRNA expression was observed after 7th injection of LPS (P<0.001. However, no significant change was observed in Cx32 protein level. Conclusion: LPS seems to modify Cx32 GJ communication in the hippocampus at transcription level but not at translation or post-translation level. In order to have a full view concerning modification of Cx32 GJ communication, effect of LPS on Cx32 channel gating should also be determined.

  8. Gene expression profiling of liver from dairy cows treated intra-mammary with lipopolysaccharide

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    Vels Lotte

    2008-09-01

    Full Text Available Abstract Background Liver plays a profound role in the acute phase response (APR observed in the early phase of acute bovine mastitis caused by Escherichia coli (E. coli. To gain an insight into the genes and pathways involved in hepatic APR of dairy cows we performed a global gene expression analysis of liver tissue sampled at different time points before and after intra-mammary (IM exposure to E. coli lipopolysaccharide (LPS treatment. Results Approximately 20% target transcripts were differentially expressed and eight co-expression clusters were identified. Each cluster had a unique time-dependent expression profile and consisted of genes involved in different biological processes. Our findings suggest that APR in the liver is triggered by the activation of signaling pathways that are involved with common and hepatic-specific transcription factors and pro-inflammatory cytokines. These mediators in turn stimulated or repressed the expression of genes encoding acute phase proteins (APP, collectins, complement components, chemokines, cell adhesion molecules and key metabolic enzymes during the APR. Hormones, anti-inflammatory and other hypothalamus-pituitary-adrenal axis (HPAA linked mediators also seemed to participate in APR. Conclusion Performing global gene expression analysis on liver tissue from IM LPS treated cows verified that the liver plays a major role in the APR of E. coli mastitis, and that the bovine hepatic APR follows the same pattern as other mammals when they are challenged with LPS. Our work presents the first insight into the dynamic changes in gene expression in the liver that influences the induction, kinetics and clinical outcome of the APR in dairy cows.

  9. Atorvastatin reduces lipopolysaccharide-induced expression of cyclooxygenase-2 in human pulmonary epithelial cells

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    Chen Ping

    2005-04-01

    Full Text Available Abstract Objective To explore the effects of atorvastatin on expression of cyclooxygenase-2 (COX-2 in human pulmonary epithelial cells (A549. Methods A549 cells were incubated in DMEM medium containing lipopolysaccharide (LPS in the presence or absence of atorvastatin. After incubation, the medium was collected and the amount of prostaglandin E2 (PGE2 was measured by enzyme-linked immunosorbent assay (ELISA. The cells were harvested, and COX-2 mRNA and protein were analyzed by RT-PCR and western-blot respectively. Results LPS increased the expression of COX-2 mRNA and production of PGE2 in a dose- and time-dependent manner in A549. Induction of COX-2 mRNA and protein by LPS were inhibited by atorvastatin in a dose-dependent manner. Atorvastatin also significantly decreased LPS-induced production of PGE2. There was a positive correlation between reduced of COX-2 mRNA and decreased of PGE2 (r = 0.947, P Conclusion Atorvastatin down-regulates LPS-induced expression of the COX-2 and consequently inhibits production of PGE2 in cultured A549 cells.

  10. Differential protein expression in alligator leukocytes in response to bacterial lipopolysaccharide injection.

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    Merchant, Mark; Kinney, Clint; Sanders, Paige

    2009-12-01

    Blood was collected from three juvenile alligators (Alligator mississippiensis) before, and again 24h after, injection with bacterial lipopolysaccharide (LPS). The leukocytes were collected from both samples, and the proteins were extracted. Each group of proteins was labeled with a different fluorescent dye and the differences in protein expression were analyzed by two dimensional differential in-gel expressions (2D-DIGE). The proteins which appeared to be increased or decreased by treatment with LPS were selected and analyzed by MALDI-TOF to determine mass and LC-MS/MS to acquire the partial protein sequences. The peptide sequences were compared to the NCBI protein sequence database to determine homology with other sequences from other species. Several proteins of interest appeared to be increased upon LPS stimulation. Proteins with homology to human transgelin-2, fish glucose-6-phosphate dehydrogenase, amphibian α-enolase, alligator lactate dehydrogenase, fish ubiquitin-activating enzyme, and fungal β-tubulin were also increased after LPS injection. Proteins with homology to fish vimentin 4, murine heterogeneous nuclear ribonucleoprotein A3, and avian calreticulin were found to be decreased in response to LPS. In addition, five proteins, four of which were up-regulated (827, 560, 512, and 650%) and one that exhibited repressed expression (307%), did not show homology to any protein in the database, and thus may represent newly discovered proteins. We are using this biochemical approach to isolate and characterize alligator proteins with potential relevant immune function.

  11. [Effect of lipopolysaccharides extracted from Porphyromonas endodontalis on the expression of CD14 in osteoblast].

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    Jia, Ge; Qiu, Li-hong; Li, Ren; Yang, Di; Guo, Yan

    2010-10-01

    To investigate the effect of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of CD14 in osteoblast. Under the condition with or without serum, MC3T3-E1 cells were stimulated with 10 μg/mL P.e-LPS for 24 hours, then the expression of CD14 was measured using flow cytometry; the membrane CD14 mRNA was detected at different time point (0, 1, 3, 6, 12, 24 h) by RT-PCR. Statistical analysis was performed using two-sample t test, one-way ANOVA and Dunnett t test with SPSS13.0 software package. Flow cytometry showed that CD14 protein increased after the stimulation of P.e-LPS for 24 h, while the non-serum group demonstrated more increase; the membrane CD14 mRNA level was up-regulated by 10 μg/mL P.e-LPS at 1 hour, and reached the maximum at 3 h and declined after 6 h. P.e-LPS can induce the expression of CD14 in osteoblast MC3T3-E1, which indicates that P.e-LPS may play an important role in osteoblast through CD14.

  12. [Effects of Porphyromonas endodontalis lipopolysaccharides on the expression of matrix metalloproteinase-9 in mouse osteoblasts].

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    Li, X L; Yu, Y Q; Qiu, L H; Yang, D; Wang, X M; Yu, J T

    2017-08-09

    Objective: To evaluate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of matrix metalloproteinase-9 (MMP-9) mRNA and protein as well as enzyme activity in MC3T3-E1 cells and the role of nuclear factor-κB (NF-κB) in the process, so as to investigate the expression of MMP-9 dependent signaling pathways in mouse osteoblasts induced by Pe LPS. Methods: The experiment was conducted in 3 sessions: MC3T3-E1 cells were treated with various concentrations of Pe LPS (0-20 mg/L) and 10 mg/L Pe LPS for different time intervals (0-48 h). The expression of MMP-9 mRNA and protein were detected by real-time reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), while the enzyme activity was detected by gelatin zymography method. The expression of MMP-9 mRNA was also detected in 10 mg/L Pe LPS treated MC3T3-El cells after pretreated with specific NF-κB inhibitor BAY 11-7082 for l h. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. Results: The levels of MMP-9 mRNA and protein increased significantly after the treatment with various concentrations of Pe LPS (0-20 mg/L), which indicated that Pe LPS induced osteoblasts to express MMP-9 in dose dependent manners. The expression of MMP-9 protein increased from (5 395±362) ng/L (blank control group) to (12 684±375) ng/L (20 mg/L group). Maximal induction of MMP-9 mRNA expression was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 24 h. The expression of MMP-9 mRNA in the 20 mg/L group was about 7 times than that in the blank control group. After 24 h, the expression of MMP-9 mRNA decreased. Maximal expression of MMP-9 protein was found in the MC3T3-E1 cells treated with 10 mg/L Pe LPS for 48 h ([35 055±2 346] ng/L) showing the highest enzyme activity. The mRNA of MMP-9 decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h. Conclusions: Pe LPS might

  13. In-vivo expression profiling of Pseudomonas aeruginosa infections reveals niche-specific and strain-independent transcriptional programs.

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    Piotr Bielecki

    Full Text Available Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics. To gain insights into the physiology of P. aeruginosa during infection, we assessed the transcriptional programs of three different P. aeruginosa strains directly after isolation from burn wounds of humans. We compared the programs to those of the same strains using two infection models: a plant model, which consisted of the infection of the midrib of lettuce leaves, and a murine tumor model, which was obtained by infection of mice with an induced tumor in the abdomen. All control conditions of P. aeruginosa cells growing in suspension and as a biofilm were added to the analysis. We found that these different P. aeruginosa strains express a pool of distinct genetic traits that are activated under particular infection conditions regardless of their genetic variability. The knowledge herein generated will advance our understanding of P. aeruginosa virulence and provide valuable cues for the definition of prospective targets to develop novel intervention strategies.

  14. Effects of propofol on lipopolysaccharide-induced expression and release of HMGB1 in macrophages

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    Wang, T.; Wei, X.Y.; Liu, B.; Wang, L.J.; Jiang, L.H. [Department of Anesthesiology, the Third Affiliated Hospital, Zhengzhou University, Zhengzhou (China)

    2015-02-24

    This study aimed to determine the effects of different concentrations of propofol (2,6-diisopropylphenol) on lipopolysaccharide (LPS)-induced expression and release of high-mobility group box 1 protein (HMGB1) in mouse macrophages. Mouse macrophage cell line RAW264.7 cells were randomly divided into 5 treatment groups. Expression levels of HMGB1 mRNA were detected using RT-PCR, and cell culture supernatant HMGB1 protein levels were detected using enzyme-linked immunosorbent assay (ELISA). Translocation of HMGB1 from the nucleus to the cytoplasm in macrophages was observed by Western blotting and activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus was detected using ELISA. HMGB1 mRNA expression levels increased significantly in the cell culture supernatant and in cells after 24 h of stimulating RAW264.7 cells with LPS (500 ng/mL). However, HMGB1 mRNA expression levels in the P2 and P3 groups, which received 500 ng/mL LPS with 25 or 50 μmol/mL propofol, respectively, were significantly lower than those in the group receiving LPS stimulation (P<0.05). After stimulation by LPS, HMGB1 protein levels were reduced significantly in the nucleus but were increased in the cytoplasm (P<0.05). Simultaneously, the activity of NF-κB was enhanced significantly (P<0.05). After propofol intervention, HMGB1 translocation from the nucleus to the cytoplasm and NF-κB activity were inhibited significantly (each P<0.05). Thus, propofol can inhibit the LPS-induced expression and release of HMGB1 by inhibiting HMGB1 translocation and NF-κB activity in RAW264.7 cells, suggesting propofol may be protective in patients with sepsis.

  15. [Effects of lipopolysaccharides from Porphyromonas endodontalis on the expression of MIP-1α in mouse osteoblasts].

    Science.gov (United States)

    Yu, Ya-Qiong; Li, Xiao-Lin; Qiu, Li-Hong; Guo, Jia-Jie; Yang, Di; Guo, Yan

    2017-06-01

    To investigate the effects of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of macrophageinflammatoryprotein-1α (MIP-1α) mRNA and protein levels in MC3T3-E1 cells and the influence of curcumin in the process. MC3T3-E1 cells were treated with 20 mg/L P.e-LPS for different times (0-48 h). The expression of MIP-1α mRNA and protein was detected by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) and enzyme linked immunosorbent assay(ELISA). MC3T3-E1 cells were pretreated with inhibitor of (curcumin) for 1 h, and then treated with 20 mg/L P.e-LPS. The expression of MIP-1α was also detected by real-time RT-PCR and ELISA.Statistical analysis was performed using one-way ANOVA and Dunnett's t test with SPSS 13.0 software package. In the observation time (0-48 h), the impact of 20 P.e-LPS mg/L on induction of MIP-1α in MC3T3-El cells exhibited a time-dependent manner. The expression of MIP-1α mRNA and protein decreased significantly after pretreatment with 10 μmol/L curcumin for 1 h. The results suggest that P.e-LPS may mediate MIP-1α expression in MC3T3-E1 cells, and curcumin has a significant inhibitory effect on this process.

  16. Lipopolysaccharide regulated protein expression is only partly impaired in monocytes from patients with type I diabetes

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    Abke Sabine

    2006-03-01

    Full Text Available Abstract Background Monocytes play an important role in innate immunity and atherosclerosis. A disturbed secretion of cytokines in lipopolysaccharide (LPS activated monocytes from type 1 diabetes (T1D patients has been described and may contribute to the impaired inflammatory response in these individuals. In the present study the influence of LPS on five different proteins with a function in immunity and atherosclerosis was analyzed in monocytes from controls and T1D patients. Methods Monocytes were isolated from controls and T1D patients and the LPS-stimulated increase of IL-6, CXCL8, monocyte chemotactic protein 1 (CCL2, MCP-1 and superoxide dismutase (SOD 2, as well as the LPS-mediated decrease of apolipoprotein E (Apo E in primary human monocytes from controls and T1D patients was determined. Results CCL2 and IL-6 secretion in response to LPS was found significantly reduced in monocytes from T1D patients when compared to controls whereas basal CCL2 release was similar in control and T1D cells. In contrast, CXCL8 and apolipoprotein E secretion and SOD 2 expression upon LPS stimulation is similar from T1D and control monocytes. Conclusion These data indicate that LPS-mediated protein expression is only partly disturbed in monocytes from T1D patients. Reduced secretion of IL-6 and CCL2 in activated monocytes of these patients may contribute to an impaired inflammatory response and vascular disease.

  17. Structural Insight into the Gene Expression Profiling of the hcn Operon in Pseudomonas aeruginosa.

    Science.gov (United States)

    Chowdhury, Nilkanta; Bagchi, Angshuman

    2017-07-01

    Pseudomonas aeruginosa is a common opportunistic human pathogen. It generally attacks immunosuppressed patients like AIDS, cancer, cystic fibrosis, etc. The virulence of P. aeruginosa is mediated by various virulence factors. One of such potential virulence factors is HCN synthesized by HCN synthase enzyme, which is encoded by the hcnABC operon. The expressions of the genes of this operon are regulated by three transcriptional regulators, viz., LasR, ANR, and RhlR. In our previous work, we analyzed the molecular details of the functionalities of LasR. In this work, we focused on ANR. ANR is a regulatory protein which belongs to the FNR family and works in anaerobic condition. ANR binds to the promoter DNA, named ANR box, as a dimer. The dimerization of this ANR protein is regulated by Fe 4 S 4 , an iron-sulfur cluster. This dimer of ANR (ANR-Fe 4 S 4 /ANR-Fe 4 S 4 ) recognizes and binds the promoter DNA sequence and regulates the transcription of this hcnABC operon. Till date, the biomolecular details of the interactions of ANR dimer with the promoter DNA are not fully understood. Thus, we built the molecular model of ANR-Fe 4 S 4 /ANR-Fe 4 S 4 . We docked the complex with the corresponding promoter DNA region. We analyzed the mode of interactions with the promoter DNA under different conditions. Thus, we tried to analyze the functionality of the ANR protein during the expressions of the genes of the hcnABC operon. So far, this is the first report to detail the molecular mechanism of the gene expression in P. aeruginosa.

  18. Expression of antisense small RNAs in response to stress in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Gómez Lozano, María; Marvig, Rasmus Lykke; Tulstrup, Monica Vera-Lise

    2014-01-01

    Background: RNA sequencing technologies reveal that bacteria express RNA molecules other than mRNA, rRNA or tRNA. During the last years genome-wide bacterial transcriptomes have been shown to comprise intergenic RNA, antisense RNA, and untranslated regions, all capable of performing diverse...... that the extent of overlap between the studies is very limited. Conclusions: RNA-seq experiments are revealing hundreds of novel transcripts in all bacterial genomes investigated. The comparison between independent studies that used RNA-seq to detect novel asRNAs in P. aeruginosa shows that the overlap between...

  19. [Effect of lipopolysaccharides from Porphyromonas endodontalis on the expression of interleukin-34 in mouse osteoblasts].

    Science.gov (United States)

    Yu, Ya-Qiong; Guo, Jia-Jie; Qiu, Li-Hong; Li, Xiao-Lin; Yang, Di; Guo, Yan

    2017-02-01

    To investigate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (P.e) on the expression of interleukin-34 (IL-34) mRNA in MC3T3-E1 cells and the role of p38MAPK, ERK1/2, NF-κB and SIRT1 in the process. MC3T3-E1 cells were treated with different concentrations of P.e-LPS(0-50 mg/L) and 20 mg/L P.e-LPS for different time (0-24 h). The expression of IL-34 mRNA was detected by real-time reverse transcription-polymerase chain reaction (real time RT-PCR). MC3T3-E1 cells were pretreated with inhibitor of NF-κB(BAY 11-7082),inhibitor of p38MAPK (SB203580), inhibitor of ERK1/2 (PD98059), agonist of sirtuin1 (SIRT1) [resveratrol (RES)] and inhibitor of SIRT1 (EX-527) for 1 h, and then were treated with 20 mg/L P.e-LPS. The expression of IL-34 mRNA was detected by real time RT-PCR. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. The level of IL-34 mRNA increased significantly after treatment with different concentrations of P.e-LPS(0-50 mg/L),which indicated that P.e-LPS induced osteoblasts to express IL-34 mRNA in a dose-dependent manner. Maximal induction of IL-34 mRNA expression was observed in MC3T3-E1 cells treated with 20 mg/L P.e-LPS for 24 h.At 48 h, the expression of IL-34 mRNA decreased gradually. The mRNA of IL-34 decreased significantly after pretreatment with 10 μmol/L BAY-117082, SB203580 and PD98059 for 1 h. P.e-LPS-induced IL-34 upregulation was attenuated by pretreatment with RES, but increased by EX-527. These results suggest that P.e-LPS may mediate IL-34 mRNA expression in MC3T3-E1 cells. This process is dependent, at least in part, on p38MAPK, ERK1/2, NF-κB and SIRT1 signaling pathways.

  20. Modulation of epithelial sodium channel (ENaC expression in mouse lung infected with Pseudomonas aeruginosa

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    Radzioch Danuta

    2005-01-01

    Full Text Available Abstract Background The intratracheal instillation of Pseudomonas aeruginosa entrapped in agar beads in the mouse lung leads to chronic lung infection in susceptible mouse strains. As the infection generates a strong inflammatory response with some lung edema, we tested if it could modulate the expression of genes involved in lung liquid clearance, such as the α, β and γ subunits of the epithelial sodium channel (ENaC and the catalytic subunit of Na+-K+-ATPase. Methods Pseudomonas aeruginosa entrapped in agar beads were instilled in the lung of resistant (BalB/c and susceptible (DBA/2, C57BL/6 and A/J mouse strains. The mRNA expression of ENaC and Na+-K+-ATPase subunits was tested in the lung by Northern blot following a 3 hours to 14 days infection. Results The infection of the different mouse strains evoked regulation of α and β ENaC mRNA. Following Pseudomonas instillation, the expression of αENaC mRNA decreased to a median of 43% on days 3 and 7 after infection and was still decreased to a median of 45% 14 days after infection (p 1Na+-K+-ATPase mRNA, the catalytic subunit of the sodium pump, was recorded. The distinctive expression profiles of the three subunits were not different, between the susceptible and resistant mouse strains. Conclusions These results show that Pseudomonas infection, by modulating ENaC subunit expression, could influence edema formation and clearance in infected lungs.

  1. Evolutionary conservation of essential and highly expressed genes in Pseudomonas aeruginosa

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    Scharfe Maren

    2010-04-01

    Full Text Available Abstract Background The constant increase in development and spread of bacterial resistance to antibiotics poses a serious threat to human health. New sequencing technologies are now on the horizon that will yield massive increases in our capacity for DNA sequencing and will revolutionize the drug discovery process. Since essential genes are promising novel antibiotic targets, the prediction of gene essentiality based on genomic information has become a major focus. Results In this study we demonstrate that pooled sequencing is applicable for the analysis of sequence variations of strain collections with more than 10 individual isolates. Pooled sequencing of 36 clinical Pseudomonas aeruginosa isolates revealed that essential and highly expressed proteins evolve at lower rates, whereas extracellular proteins evolve at higher rates. We furthermore refined the list of experimentally essential P. aeruginosa genes, and identified 980 genes that show no sequence variation at all. Among the conserved nonessential genes we found several that are involved in regulation, motility and virulence, indicating that they represent factors of evolutionary importance for the lifestyle of a successful environmental bacterium and opportunistic pathogen. Conclusion The detailed analysis of a comprehensive set of P. aeruginosa genomes in this study clearly disclosed detailed information of the genomic makeup and revealed a large set of highly conserved genes that play an important role for the lifestyle of this microorganism. Sequencing strain collections enables for a detailed and extensive identification of sequence variations as potential bacterial adaptation processes, e.g., during the development of antibiotic resistance in the clinical setting and thus may be the basis to uncover putative targets for novel treatment strategies.

  2. Analysis of MicroRNA Expression Profiles in Weaned Pig Skeletal Muscle after Lipopolysaccharide Challenge

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    Jing Zhang

    2015-09-01

    Full Text Available MicroRNAs (miRNAs constitute a class of non-coding RNAs that play a crucial regulatory role in skeletal muscle development and disease. Several acute inflammation conditions including sepsis and cancer are characterized by a loss of skeletal muscle due primarily to excessive muscle catabolism. As a well-known inducer of acute inflammation, a lipopolysaccharide (LPS challenge can cause serious skeletal muscle wasting. However, knowledge of the role of miRNAs in the course of inflammatory muscle catabolism is still very limited. In this study, RNA extracted from the skeletal muscle of pigs injected with LPS or saline was subjected to small RNA deep sequencing. We identified 304 conserved and 114 novel candidate miRNAs in the pig. Of these, four were significantly increased in the LPS-challenged samples and five were decreased. The expression of five miRNAs (ssc-miR-146a-5p, ssc-miR-221-5p, ssc-miR-148b-3p, ssc-miR-215 and ssc-miR-192 were selected for validation by quantitative polymerase chain reaction (qPCR, which found that ssc-miR-146a-5p and ssc-miR-221-5p were significantly upregulated in LPS-challenged pig skeletal muscle. Moreover, we treated mouse C2C12 myotubes with 1000 ng/mL LPS as an acute inflammation cell model. Expression of TNF-α, IL-6, muscle atrophy F-box (MAFbx and muscle RING finger 1 (MuRF1 mRNA was strongly induced by LPS. Importantly, miR-146a-5p and miR-221-5p also showed markedly increased expression in LPS-treated C2C12 myotubes, suggesting the two miRNAs may be involved in muscle catabolism systems in response to acute inflammation caused by a LPS challenge. To our knowledge, this study is the first to examine miRNA expression profiles in weaned pig skeletal muscle challenged with LPS, and furthers our understanding of miRNA function in the regulation of inflammatory muscle catabolism.

  3. Cytokine and acute phase protein gene expression in liver biopsies from dairy cows with a lipopolysaccharide - induced mastitis

    DEFF Research Database (Denmark)

    Vels, J; Røntved, Christine M.; Bjerring, Martin

    2009-01-01

    A minimally invasive liver biopsy technique was tested for its applicability to study the hepatic acute phase response (APR) in dairy cows with Escherichia coli lipopolysaccharide (LPS)-induced mastitis. The hepatic mRNA expression profiles of the inflammatory cytokines, tumor necrosis factor (TNF......, a minimally invasive liver biopsy technique can be used for studying the hepatic APR in diseased cattle. Lipopolysaccharide-induced mastitis resulted in a time-dependent production of inflammatory cytokines and SAA and Hp in the liver of dairy cows.......- ), IL-1β, IL-6, and IL-10, and the acute phase proteins serum amyloid A isoform 3 (SAA3), haptoglobin (Hp), and 1-acid glycoprotein (AGP) were determined by real-time reverse transcription-PCR. Fourteen primiparous cows in mid lactation were challenged with 200 µg of LPS (n = 8) or NaCl solution (n = 6...

  4. Expression of the recA gene of Pseudomonas aeruginosa PAO is inducible by DNA-damaging agents

    International Nuclear Information System (INIS)

    Miller, R.V.; Kokjohn, T.A.

    1988-01-01

    Western (immunoblot) analysis using Escherichia coli anti-RecA antiserum revealed that expression of the RecA protein of Pseudomonas aeruginosa PAO is induced upon exposure of the bacterium to UV irradiation or norfloxacin, a quinolone related to nalidixic acid

  5. Epigenetic control of virulence gene expression in Pseudomonas aeruginosa by a LysR-type transcription regulator.

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    Keith H Turner

    2009-12-01

    Full Text Available Phenotypic variation within an isogenic bacterial population is thought to ensure the survival of a subset of cells in adverse conditions. The opportunistic pathogen Pseudomonas aeruginosa variably expresses several phenotypes, including antibiotic resistance, biofilm formation, and the production of CupA fimbriae. Here we describe a previously unidentified bistable switch in P. aeruginosa. This switch controls the expression of a diverse set of genes, including aprA, which encodes the secreted virulence factor alkaline protease. We present evidence that bistable expression of PA2432, herein named bexR (bistable expression regulator, which encodes a LysR-type transcription regulator, controls this switch. In particular, using DNA microarrays, quantitative RT-PCR analysis, chromatin immunoprecipitation, and reporter gene fusions, we identify genes directly under the control of BexR and show that these genes are bistably expressed. Furthermore, we show that bexR is itself bistably expressed and positively autoregulated. Finally, using single-cell analyses of a GFP reporter fusion, we present evidence that positive autoregulation of bexR is necessary for bistable expression of the BexR regulon. Our findings suggest that a positive feedback loop involving a LysR-type transcription regulator serves as the basis for an epigenetic switch that controls virulence gene expression in P. aeruginosa.

  6. Co-Cultures of Pseudomonas aeruginosa and Roseobacter denitrificans Reveal Shifts in Gene Expression Levels Compared to Solo Cultures

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    Crystal A. Conway

    2012-01-01

    Full Text Available Consistent biosynthesis of desired secondary metabolites (SMs from pure microbial cultures is often unreliable. In a proof-of-principle study to induce SM gene expression and production, we describe mixed “co-culturing” conditions and monitoring of messages via quantitative real-time PCR (qPCR. Gene expression of model bacterial strains (Pseudomonas aeruginosa PAO1 and Roseobacter denitrificans Och114 was analyzed in pure solo and mixed cocultures to infer the effects of interspecies interactions on gene expression in vitro, Two P. aeruginosa genes (PhzH coding for portions of the phenazine antibiotic pathway leading to pyocyanin (PCN and the RhdA gene for thiosulfate: cyanide sulfurtransferase (Rhodanese and two R. denitrificans genes (BetaLact for metallo-beta-lactamase and the DMSP gene for dimethylpropiothetin dethiomethylase were assessed for differential expression. Results showed that R. denitrificans DMSP and BetaLact gene expression became elevated in a mixed culture. In contrast, P. aeruginosa co-cultures with R. denitrificans or a third species did not increase target gene expression above control levels. This paper provides insight for better control of target SM gene expression in vitro and bypass complex genetic engineering manipulations.

  7. In vivo functional expression of a screened P. aeruginosa chaperone-dependent lipase in E. coli

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    Wu Xiangping

    2012-09-01

    Full Text Available Abstract Background Microbial lipases particularly Pseudomonas lipases are widely used for biotechnological applications. It is a meaningful work to design experiments to obtain high-level active lipase. There is a limiting factor for functional overexpression of the Pseudomonas lipase that a chaperone is necessary for effective folding. As previously reported, several methods had been used to resolve the problem. In this work, the lipase (LipA and its chaperone (LipB from a screened strain named AB which belongs to Pseudomonas aeruginosa were overexpressed in E. coli with two dual expression plasmid systems to enhance the production of the active lipase LipA without in vitro refolding process. Results In this work, we screened a lipase-produced strain named AB through the screening procedure, which was identified as P. aeruginosa on the basis of 16S rDNA. Genomic DNA obtained from the strain was used to isolate the gene lipA (936 bp and lipase specific foldase gene lipB (1023 bp. One single expression plasmid system E. coli BL21/pET28a-lipAB and two dual expression plasmid systems E. coli BL21/pETDuet-lipA-lipB and E. coli BL21/pACYCDuet-lipA-lipB were successfully constructed. The lipase activities of the three expression systems were compared to choose the optimal expression method. Under the same cultured condition, the activities of the lipases expressed by E. coli BL21/pET28a-lipAB and E. coli BL21/pETDuet-lipA-lipB were 1300 U/L and 3200 U/L, respectively, while the activity of the lipase expressed by E. coli BL21/pACYCDuet-lipA-lipB was up to 8500 U/L. The lipase LipA had an optimal temperature of 30°C and an optimal pH of 9 with a strong pH tolerance. The active LipA could catalyze the reaction between fatty alcohols and fatty acids to generate fatty acid alkyl esters, which meant that LipA was able to catalyze esterification reaction. The most suitable fatty acid and alcohol substrates for esterification were octylic acid and hexanol

  8. Expression, purification, crystallization and preliminary crystallographic analysis of PA3885 (TpbA) from Pseudomonas aeruginosa PAO1

    International Nuclear Information System (INIS)

    Yang, Wen; Li, Kan; Bai, Yuwei; Zhou, Ruimin; Zhou, Weihong; Bartlam, Mark

    2010-01-01

    PA3885 (TpbA), a tyrosine phosphatase, may function as a balancing factor between biofilm formation and motility in the opportunistic pathogen P. aeruginosa. Here, the expression, purification, crystallization and preliminary crystallographic analysis of PA3885 from P. aeruginosa PAO1 are reported. Biofilms are important in cell communication and growth in most bacteria and are also responsible for most human clinical infections and diseases. Quorum-sensing systems have been identified to be crucial for biofilm formation and regulation. PA3885 (TpbA), a tyrosine phosphatase, is reported to convert extracellular quorum-sensing signals into internal gene-cascade reactions that result in reduced biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa. Here, PA3885 from P. aeruginosa PAO1 was expressed, purified and crystallized. Single crystals were studied by X-ray crystallography and native diffraction data were collected to 2.8 Å resolution. These crystals were determined to belong to space group C2. It was not possible to conclusively determine the number of proteins in the asymmetric unit from the preliminary X-ray diffraction data analysis alone and attempts to determine the crystal structure of PA3885 are currently under way

  9. The pvc operon regulates the expression of the Pseudomonas aeruginosa fimbrial chaperone/usher pathway (cup genes.

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    Uzma Qaisar

    Full Text Available The Pseudomonas aeruginosa fimbrial structures encoded by the cup gene clusters (cupB and cupC contribute to its attachment to abiotic surfaces and biofilm formation. The P. aeruginosa pvcABCD gene cluster encodes enzymes that synthesize a novel isonitrile functionalized cumarin, paerucumarin. Paerucumarin has already been characterized chemically, but this is the first report elucidating its role in bacterial biology. We examined the relationship between the pvc operon and the cup gene clusters in the P. aeruginosa strain MPAO1. Mutations within the pvc genes compromised biofilm development and significantly reduced the expression of cupB1-6 and cupC1-3, as well as different genes of the cupB/cupC two-component regulatory systems, roc1/roc2. Adjacent to pvc is the transcriptional regulator ptxR. A ptxR mutation in MPAO1 significantly reduced the expression of the pvc genes, the cupB/cupC genes, and the roc1/roc2 genes. Overexpression of the intact chromosomally-encoded pvc operon by a ptxR plasmid significantly enhanced cupB2, cupC2, rocS1, and rocS2 expression and biofilm development. Exogenously added paerucumarin significantly increased the expression of cupB2, cupC2, rocS1 and rocS2 in the pvcA mutant. Our results suggest that pvc influences P. aeruginosa biofilm development through the cup gene clusters in a pathway that involves paerucumarin, PtxR, and different cup regulators.

  10. The Effect of Silybin Encapsulated in Nanoparticles on oprM Gene Expression in Drug Resistant Isolates of Pseudomonas Aeruginosa

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    Aref Mohammadipour

    2017-08-01

    Full Text Available Abstract Background: Pseudomonas aeruginosa is an opportunistic nosocomial pathogen that using several classes of antibiotics to treat has been led to the emergence of multiple drug resistance. One of the drug resistance mechanisms in Pseudomonas aeruginosa is overexpression of mexXY-oprM efflux pump system. Silybin as main flavonolignan of silymarin extracted from Silybum marianum is a hepatoprotective agent that its anti-bacterial properties was studied, recently. In this study, the effect of combination of silybin and ciprofloxacin on oprM gene expression in clinical isolates of Pseudomonas aeruginosa was evaluated. Materials and Methods: In this study, seven ciprofloxacin resistant isolates of Pseudomonas aeruginosa were treated by ciprofloxacin (1/2MIC only (control sample and in the combination with silybin-encapsulated micelle (nanoparticles (test sample. After 24h, RNA extraction and cDNA synthesis were performed in silybin treated and un-treated cells and oprM gene expression was quantitatively investigated by realtime PCR method. Results: Results of this study showed that a silybin encapsulated in nanoparticles (400µg/ml induces death up to 50% in resistant isolates treated by ciprofloxacin (1/2MIC during 24h. Also, quantitative Real-Time PCR analysis revealed that silybin encapsulated in nanoparticles decreases the expression of oprM gene compared to silybin untreated cells. Conclusion: It seems that Decrease of oprM expression in resistant isolates lead to decrease of mexAB-oprM and mexXY-oprM in cell surface, subsequently decrease of antibiotic withdrawal to extracellular environment and increase of sensitivity to antibiotics.

  11. TLR4-NOX4-AP-1 signaling mediates lipopolysaccharide-induced CXCR6 expression in human aortic smooth muscle cells

    International Nuclear Information System (INIS)

    Patel, Devang N.; Bailey, Steven R.; Gresham, John K.; Schuchman, David B.; Shelhamer, James H.; Goldstein, Barry J.; Foxwell, Brian M.; Stemerman, Michael B.; Maranchie, Jodi K.; Valente, Anthony J.; Mummidi, Srinivas; Chandrasekar, Bysani

    2006-01-01

    CXCL16 is a transmembrane non-ELR CXC chemokine that signals via CXCR6 to induce aortic smooth muscle cell (ASMC) proliferation. While bacterial lipopolysaccharide (LPS) has been shown to stimulate CXCL16 expression in SMC, its effects on CXCR6 are not known. Here, we demonstrate that LPS upregulates CXCR6 mRNA, protein, and surface expression in human ASMC. Inhibition of TLR4 with neutralizing antibodies or specific siRNA interference blocked LPS-mediated CXCR6 expression. LPS stimulated both AP-1 (c-Fos, c-Jun) and NF-κB (p50 and p65) activation, but only inhibition of AP-1 attenuated LPS-induced CXCR6 expression. Using dominant negative expression vectors and siRNA interference, we demonstrate that LPS induces AP-1 activation via MyD88, TRAF6, ERK1/2, and JNK signaling pathways. Furthermore, the flavoprotein inhibitor diphenyleniodonium chloride significantly attenuated LPS-mediated AP-1-dependent CXCR6 expression, as did inhibition of NOX4 NADPH oxidase by siRNA. Finally, CXCR6 knockdown inhibited CXCL16-induced ASMC proliferation. These results demonstrate that LPS-TLR4-NOX4-AP-1 signaling can induce CXCR6 expression in ASMC, and suggest that the CXCL16-CXCR6 axis may be an important proinflammatory pathway in the pathogenesis of atherosclerosis

  12. Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV-C radiation.

    Science.gov (United States)

    Salma, Kloula Ben Ghorbal; Lobna, Maalej; Sana, Khefacha; Kalthoum, Chourabi; Imene, Ouzari; Abdelwaheb, Chatti

    2016-07-01

    It was well known that, UV-C irradiation increase considerably the reactive oxygen species (ROS) levels in eukaryotic and prokaryotic organisms. In the enzymatic ROS-scavenging pathways, superoxide dismutase (SOD), Catalase (CAT), and peroxidase (POX) were developed to deal with oxidative stress. In this study, we investigated the effects of UV-C radiations on antioxidant enzymes (catalase, superoxide dismutase, and peroxidases) expression in Pseudomonas aeruginosa. Catalase, superoxide dismutase, and peroxidases activities were determined spectrophotometrically. Isozymes of superoxide dismutase were revealed by native gel activity staining method. Lipid peroxidation was determined by measuring malondialdehyde formation. Our results showed that superoxide dismutase, catalase and peroxidase activities exhibited a gradual increase during the exposure time (30 min). However, the superoxide dismutase activity was maximized at 15 min. Native gel activity staining assays showed the presence of three superoxide dismutase isozymes. The iron-cofactored isoform activity was altered after exposure to UV-C stress. These finding suggest that catalase and peroxidase enzymes have the same importance toward UV-C rays at shorter and longer exposure times and this may confer additional protection to superoxide dismutase from damage caused by lipid peroxidation. Moreover, our data demonstrate the significant role of the antioxidant system in the resistance of this important human pathogen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Neisseria meningitidis expressing lgtB lipopolysaccharide targets DC-SIGN and modulates dendritic cell function.

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    Steeghs, Liana; van Vliet, Sandra J; Uronen-Hansson, Heli; van Mourik, Andries; Engering, Anneke; Sanchez-Hernandez, Martha; Klein, Nigel; Callard, Robin; van Putten, Jos P M; van der Ley, Peter; van Kooyk, Yvette; van de Winkel, Jan G J

    2006-02-01

    Neisseria meningitidis lipopolysaccharide (LPS) has been identified as a major determinant of dendritic cell (DC) function. Here we report that one of a series of meningococcal mutants with defined truncations in the lacto-N-neotetraose outer core of the LPS exhibited unique strong adhesion and internalization properties towards DC. These properties were mediated by interaction of the GlcNAc(beta1-3)-Gal(beta1-4)-Glc-R oligosaccharide outer core of lgtB LPS with the dendritic-cell-specific ICAM-3 grabbing non-integrin (DC-SIGN) lectin receptor. Activation of DC-SIGN with this novel oligosaccharide ligand skewed T-cell responses driven by DC towards T helper type 1 activity. Thus, the use of lgtB LPS may provide a powerful instrument to selectively induce the desired arm of the immune response and potentially increase vaccine efficacy.

  14. The effects of quercetin on microRNA and inflammatory gene expression in lipopolysaccharide-stimulated bovine neutrophils

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    Phongsakorn Chuammitri

    2017-04-01

    Full Text Available Aim: To investigate gene expression of microRNA (miRNA milieus (MIRLET7E, MIR17, MIR24-2, MIR146A, and MIR181C, inflammatory cytokine genes (interleukin 1β [IL1B], IL6, CXCL8, and tumor necrosis factor [TNF], and the pathogen receptor toll-like receptor (TLR4 in bovine neutrophils under quercetin supplementation. Materials and Methods: Isolated bovine neutrophils were incubated with bacterial lipopolysaccharide under quercetin treatment or left untreated. Real-time polymerase chain reaction was performed to determine the expression of the miRNAs and messenger RNA (mRNA transcripts in neutrophils. Results: Quercetin-treated neutrophils exhibited a remarkable suppression in MIR24-2, MIR146A, and MIR181C expression. Similarly, mRNA expression of IL1B, IL6, CXCL8, TLR4, and TNF genes noticeably declined in the quercetin group. Many proinflammatory genes (IL1B, IL6, and CXCL8 and the pathogen receptor TLR4 had a negative correlation with MIR146A and MIR181C as revealed by Pearson correlation. Conclusion: Interaction between cognate mRNAs and miRNAs under quercetin supplementation can be summarized as a positive or negative correlation. This finding may help understand the effects of quercetin either on miRNA or gene expression during inflammation, especially as a potentially applicable indicator in bovine mastitis.

  15. Lipopolysaccharide-binding protein and leptin are associated with stress-induced interleukin-6 cytokine expression ex vivo in obesity.

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    Huang, Chun-Jung; Stewart, Jennifer K; Shibata, Yoshimi; Slusher, Aaron L; Acevedo, Edmund O

    2015-05-01

    Obesity is associated with enhanced inflammation and mental stress, but limited information has addressed the potential additive effect of psychological stress on obesity-associated inflammation. This study examined whether obese subjects would elicit a greater host immune response (IL-6 mRNA and cytokine) to lipopolysaccharide (LPS) in response to mental stress. Blood samples for LPS-stimulated IL-6 mRNA and cytokine were collected prior to and following mental stress. Results showed that obese subjects elicited a greater LPS-induced IL-6 along with its mRNA expression following mental stress compared to normal-weight subjects. Stress-induced IL-6 cytokine response to LPS was correlated with the baseline levels of plasma LPS binding protein (LBP) and leptin. These findings are consistent with the idea that endogenous inflammatory agents (e.g., LBP and leptin), often elevated with obesity, enhance inflammatory responses to psychological stress. © 2014 Society for Psychophysiological Research.

  16. Over-expression of TSPO in the hippocampal CA1 area alleviates cognitive dysfunction caused by lipopolysaccharide in mice.

    Science.gov (United States)

    Zhang, Hui; Ma, Li; Yin, Yan-Ling; Dong, Lian-Qiang; Cheng, Gang-Ge; Ma, Ya-Qun; Li, Yun-Feng; Xu, Bai-Nan

    2016-09-01

    The translocator protein 18kDa (TSPO) is closely related to regulation of immune/inflammatory response. However, the putative role and signaling mechanisms of TSPO in regulation of neuroinflammation remain unclear. GV287 lentiviral vectors mediating TSPO over-expression were injected into bilateral hippocampal CA1 areas to test whether TSPO over-expression was neuroprotective in lipopolysaccharide (LPS)-induced mice model. Finasteride, a blocker of allopregnanolone production, was used to test whether the protective effects were related to steroideogenesis. The results demonstrated that TSPO over-expression increased progesterone and allopregnanolone synthesis. TSPO over-expression in CA1 area improved LPS-induced cognitive deficiency in mice and this cognitive improvement was reversed by finasteride administration. These data suggest that up-regulation of TSPO level during neuroinflammation may be an adaptive response mechanism, a way to provide more neurosteroids. We confer that TSPO could be an attractive drug target for controlling neuroinflammation in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Peripheral lipopolysaccharide administration transiently affects expression of brain-derived neurotrophic factor, corticotropin and proopiomelanocortin in mouse brain.

    Science.gov (United States)

    Schnydrig, Sabine; Korner, Lukas; Landweer, Svenja; Ernst, Beat; Walker, Gaby; Otten, Uwe; Kunz, Dieter

    2007-12-11

    Peripheral inflammation induced by intraperitoneal (i.p.) injection of Lipopolysaccharide (LPS) is known to cause functional impairments in the brain affecting memory and learning. One of mechanisms may be the interference with neurotrophin (NT) expression and function. In the current study we administered a single, high dose of LPS (3mg/kg, i.p.) into mice and investigated changes in brain-derived neurotrophic factor (BDNF) gene expression within 1-6 days after LPS injection. Crude synaptosomes were isolated from brain tissue and subjected to Western-blot analyses. We found transient reductions in synaptosomal proBDNF- and BDNF protein expression, with a maximal decrease at day 3 as compared to saline injected controls. The time course of reduction of BDNF mRNA in whole brain extracts parallels the decrease in protein levels in synaptosomes. LPS effects in the central nervous system (CNS) are known to crucially involve the activation of the hypothalamic-pituitary-adrenal (HPA) axis. We analysed the time course of corticotropin releasing hormone (CRH)- and proopiomelanocortin (POMC) mRNA expression. As observed for BDNF-, CRH- and POMC mRNA levels are also significantly reduced on day 3 indicating a comparable time course. These results suggest that peripheral inflammation causes a reduction of trophic supply in the brain, including BDNF at synaptic sites. The mechanisms involved could be a negative feedback of the activated HPA axis.

  18. Lipopolysaccharide inhibits the self-renewal of spermatogonial stem cells in vitro via downregulation of GDNF expression in Sertoli cells.

    Science.gov (United States)

    Zhang, Xiaoli; Shi, Kun; Li, Yi; Zhang, Haiyu; Hao, Jing

    2014-06-01

    Lipopolysaccharide (LPS) can reduce sperm count and sperm quality. The molecular mechanisms underlying this process are not fully understood. In this report, we investigated the effects of LPS-treated Sertoli cells on self-renewal and differentiation of spermatogoinial stem cells (SSCs). Sertoli cell cultures were established and incubated with LPS (10μg/ml) for 1, 2 or 3 days, respectively. The culture media were collected and used as conditioned media (CM) to culture SSCs. The expression of glial cell-derived neurotrophic factor (GDNF), stem cell factor (SCF) and bone morphogenetic protein 4 (BMP4) in Sertoli cells treated with LPS was analyzed by RT-PCR and Western blotting. The results showed that the expression of SSC differentiation markers, c-kit and Sohlh2, was increased, while the expression of SSC self-renewal markers, plzf, oct4, and PCNA, was repressed when cultured in CM from LPS-treated Sertoli cells. GDNF levels in Sertoli cells and CM reduced dramatically after LPS treatments, while SCF and BMP4 levels did not show any significant changes. Moreover, correlated with the GDNF levels in CM, GDNF target genes, Bcl6b and Etv5, were reduced markedly in SSCs. Our results suggest that LPS inhibits the expression of GDNF in Sertoli cells, and might prevent the SSC self-renewal via down-regulation of GDNF target genes. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Modulation of macrophage Ia expression by lipopolysaccharide: Stem cell requirements, accessory lymphocyte involvement, and IA-inducing factor production

    International Nuclear Information System (INIS)

    Wentworth, P.A.; Ziegler, H.K.

    1989-01-01

    The mechanism of induction of murine macrophage Ia expression by lipopolysaccharide (LPS) was studied. Intraperitoneal injection of 1 microgram of LPS resulted in a 3- to 10-fold increase in the number of IA-positive peritoneal macrophages (flow cytometry and immunofluorescence) and a 6-to 16-fold increase by radioimmunoassay. The isolated lipid A moiety of LPS was a potent inducer of macrophage Ia expression. Ia induction required a functional myelopoietic system as indicated by the finding that the response to LPS was eliminated in irradiated (900 rads) mice and reinstated by reconstitution with bone marrow cells. Comparison of LPS-induced Ia expression in normal and LPS-primed mice revealed a faster secondary response to LPS. The memory response could be adoptively transferred to normal mice with nonadherent spleen cells prepared 60 days after LPS injection. Spleen cells prepared 5 days after LPS injection caused Ia induction in LPS-nonresponder mice; such induction was not observed in irradiated (900 rads) recipients. The cell responsible for this phenomenon was identified as a Thy-1+, immunoglobulin-negative nonadherent cell. The biosynthesis and expression of Ia were not increased by direct exposure of macrophages to LPS in vitro. Small amounts of LPS inhibited Ia induction by gamma interferon. LPS showed positive regulatory effects on Ia expression by delaying the loss of Ia expression on cultured macrophages and by stimulating the production of Ia-inducing factors. Supernatants from cultured spleen cells stimulated with LPS in vitro contained antiviral and Ia-inducing activity that was acid labile, indicating that the active factor is gamma interferon. We conclude that induction of Ia expression by LPS in vivo is a bone-marrow-dependent, radiation-sensitive process which involves the stimulation of a gamma interferon-producing accessory lymphocyte and a delay in Ia turnover

  20. The effect of garlic extract on the expression of genes elastase and exotoxin A in Pseudomonas aeruginosa

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    Batoul Kavyani

    2016-11-01

    Full Text Available Background: Multidrug-resistant bacteria make many problems in clinical therapy, design and manufacture of synthetic drugs. Pseudomonas aeruginosa is one of the most important multidrug-resistance bacteria leads to variety infections in human especially in immunocompromised, patients with severe burns, and nosocomial infections. It Recent years, this organism makes a big challenge in clinical treatment of infections using a wide range of antibiotics. Medicinal herbs for thousands of years to prevent or treat infectious diseases were considered. Today, pharmacists have high interest of using medicinal herbs to prepare a new antimicrobial compounds. The goal of this study was to investigation the effect of aqueous and alcoholic extract of fresh garlic on the expression of genes encoding elastase and exotoxin A virulence factors, in P. aeruginosa PAO1 strain. Methods: Present study was an experimental study and performed from 2015 to 2016 in Hamadan University of Medical Science, Iran. The minimal inhibitory concentration (MIC and minimal bactericidal concentration (MBC of aqueous and alcoholic extract of garlic was determined. Then in order to investigation the gene expression of elastase and exotoxin A genes, quantitative real-time polymerase chain reaction (qPCR method was performed at sub-MBC concentrations. Results: According to the results aqueous extracts of garlic had better impact in comparison with alcoholic alone. At concentration of 64 and 8 mg/ml of aqueous extract the expression of both elastase and exotoxin A genes were decreased. Although, the expression of elastase gene was most affected by garlic at different concentrations than exotoxin A. Conclusion: The results suggested that the compositions of garlic extracts can inhibit the production of virulence factors in P. aeruginosa. So in order to treat infectious diseases in the near future, medicinal plants known as new antimicrobial drugs can be used alone or with antibiotic drugs

  1. Gene sequencing, cloning, and expression of the recombinant L- Asparaginase of Pseudomonas aeruginosa SN4 strain in Escherichia coli

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    Arastoo Badoei-dalfard

    2016-03-01

    Full Text Available Introduction: L- asparaginase is in an excessive demand in medical applications and in food treating industries, the request for this therapeutic enzyme is growing several folds every year. Materials and methods: In this study, a L- asparaginase gene from Pseudomonas aeruginosa strain SN4 was sequenced and cloned in E. coli. Primers were designed based on L- asparaginase from P. aeruginosa DSM 50071, which show high similarity to SN4 strain, according to 16S rRNA sequence. The L- asparaginase gene was exposed to restriction digestion with NdeI and XhoI enzymes and then ligated into pET21a plasmid. The ligated sample was transformed into competent E. coli (DE3 pLysS DH5a cells, according to CaCl2 method. The transformed E. coli cells were grown into LB agar plate containing 100 µg/ml ampicillin, IPTG (1 mM. Results: Recombinant L- asparaginase from E. coli BL21 induced after 9 h of incubation and showed high L- asparaginase activity about 93.4 IU/ml. Recombinant L- asparaginase sequencing and alignments showed that the presumed amino acid sequence composed of 350 amino acid residues showed high similarity with P. aeruginosa L- asparaginases about 99%. The results also indicated that SN4 L- asparaginase has the catalytic residues and conserve region similar to other L- asparaginases. Discussion and conclusion: This is the first report on cloning and expression of P. aeruginosa L- asparaginases in Escherichia coli. These results indicated a potent source of L- asparaginase for in vitro and in vivio anticancer consideration. 

  2. Heat Stress and Lipopolysaccharide Stimulation of Chicken Macrophage-Like Cell Line Activates Expression of Distinct Sets of Genes.

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    Anna Slawinska

    Full Text Available Acute heat stress requires immediate adjustment of the stressed individual to sudden changes of ambient temperatures. Chickens are particularly sensitive to heat stress due to development of insufficient physiological mechanisms to mitigate its effects. One of the symptoms of heat stress is endotoxemia that results from release of the lipopolysaccharide (LPS from the guts. Heat-related cytotoxicity is mitigated by the innate immune system, which is comprised mostly of phagocytic cells such as monocytes and macrophages. The objective of this study was to analyze the molecular responses of the chicken macrophage-like HD11 cell line to combined heat stress and lipopolysaccharide treatment in vitro. The cells were heat-stressed and then allowed a temperature-recovery period, during which the gene expression was investigated. LPS was added to the cells to mimic the heat-stress-related endotoxemia. Semi high-throughput gene expression analysis was used to study a gene panel comprised of heat shock proteins, stress-related genes, signaling molecules and immune response genes. HD11 cell line responded to heat stress with increased mRNA abundance of the HSP25, HSPA2 and HSPH1 chaperones as well as DNAJA4 and DNAJB6 co-chaperones. The anti-apoptotic gene BAG3 was also highly up-regulated, providing evidence that the cells expressed pro-survival processes. The immune response of the HD11 cell line to LPS in the heat stress environment (up-regulation of CCL4, CCL5, IL1B, IL8 and iNOS was higher than in thermoneutral conditions. However, the peak in the transcriptional regulation of the immune genes was after two hours of temperature-recovery. Therefore, we propose the potential influence of the extracellular heat shock proteins not only in mitigating effects of abiotic stress but also in triggering the higher level of the immune responses. Finally, use of correlation networks for the data analysis aided in discovering subtle differences in the gene

  3. Lipopolysaccharide causes deficits in spatial learning in the watermaze but not in BDNF expression in the rat dentate gyrus.

    Science.gov (United States)

    Shaw, K N; Commins, S; O'Mara, S M

    2001-09-28

    We investigated the effects of a single injection and a daily injection of lipopolysaccharide (LPS) on spatial learning and brain-derived neurotrophic factor (BDNF) expression in the rat dentate gyrus. LPS is derived from the cell wall of Gram-negative bacteria and is a potent endotoxin that causes the release of cytokines such as interleukin-1 and tumour necrosis factor. LPS is thought to activate both the neuroimmune and neuroendocrine systems; it also blocks long-term potentiation in the hippocampus. Here, we examined the effects of LPS on a form of hippocampal-dependent learning-spatial learning in the water maze. Rats were injected with LPS intraperitoneally (100 microg/kg) and trained in the water maze. The first group of rats were injected on day 1 of training, 4 h prior to learning the water maze task. Groups 2 and 3 were injected daily, again 4 h prior to the water-maze task; group 2 with LPS and group 3 with saline. A number of behavioural variables were recorded by a computerised tracking system for each trial. The behavioural results showed a single injection of LPS (group 1) impaired escape latency in both the acquisition and retention phases of the study, whereas a daily injection of LPS did not significantly impair acquisition or retention. BDNF expression was analysed in the dentate gyrus of all animals. No significant differences in BDNF expression were found between the three groups.

  4. High-resolution time series of Pseudomonas aeruginosa gene expression and rhamnolipid secretion through growth curve synchronization

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    Xavier João B

    2011-06-01

    Full Text Available Abstract Background Online spectrophotometric measurements allow monitoring dynamic biological processes with high-time resolution. Contrastingly, numerous other methods require laborious treatment of samples and can only be carried out offline. Integrating both types of measurement would allow analyzing biological processes more comprehensively. A typical example of this problem is acquiring quantitative data on rhamnolipid secretion by the opportunistic pathogen Pseudomonas aeruginosa. P. aeruginosa cell growth can be measured by optical density (OD600 and gene expression can be measured using reporter fusions with a fluorescent protein, allowing high time resolution monitoring. However, measuring the secreted rhamnolipid biosurfactants requires laborious sample processing, which makes this an offline measurement. Results Here, we propose a method to integrate growth curve data with endpoint measurements of secreted metabolites that is inspired by a model of exponential cell growth. If serial diluting an inoculum gives reproducible time series shifted in time, then time series of endpoint measurements can be reconstructed using calculated time shifts between dilutions. We illustrate the method using measured rhamnolipid secretion by P. aeruginosa as endpoint measurements and we integrate these measurements with high-resolution growth curves measured by OD600 and expression of rhamnolipid synthesis genes monitored using a reporter fusion. Two-fold serial dilution allowed integrating rhamnolipid measurements at a ~0.4 h-1 frequency with high-time resolved data measured at a 6 h-1 frequency. We show how this simple method can be used in combination with mutants lacking specific genes in the rhamnolipid synthesis or quorum sensing regulation to acquire rich dynamic data on P. aeruginosa virulence regulation. Additionally, the linear relation between the ratio of inocula and the time-shift between curves produces high-precision measurements of

  5. Effect of penehyclidine hydrochloride on β-arrestin-1 expression in lipopolysaccharide-induced human pulmonary microvascular endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, J. [Department of Anesthesiology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei (China); Xiao, F. [Department of Osteology, Pu Ai Hospital, Huazhong University of Science and Technology, Wuhan, Hubei (China); Zhang, Z.Z.; Wang, Y.P.; Chen, K.; Wang, Y.L. [Department of Anesthesiology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei (China)

    2013-12-02

    β-arrestins are expressed proteins that were first described, and are well-known, as negative regulators of G protein-coupled receptor signaling. Penehyclidine hydrochloride (PHC) is a new anti-cholinergic drug that can inhibit biomembrane lipid peroxidation, and decrease cytokines and oxyradicals. However, to date, no reports on the effects of PHC on β-arrestin-1 in cells have been published. The aim of this study was to investigate the effect of PHC on β-arrestin-1 expression in lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cells (HPMEC). Cultured HPMEC were pretreated with PHC, followed by LPS treatment. Muscarinic receptor mRNAs were assayed by real-time quantitative PCR. Cell viability was assayed by the methyl thiazolyl tetrazolium (MTT) conversion test. The dose and time effects of PHC on β-arrestin-1 expression in LPS-induced HPMEC were determined by Western blot analysis. Cell malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were measured. It was found that the M{sub 3} receptor was the one most highly expressed, and was activated 5 min after LPS challenge. Furthermore, 2 μg/mL PHC significantly upregulated expression of β-arrestin-1 within 10 to 15 min. Compared with the control group, MDA levels in cells were remarkably increased and SOD activities were significantly decreased in LPS pretreated cells, while PHC markedly decreased MDA levels and increased SOD activities. We conclude that PHC attenuated ROS injury by upregulating β-arrestin-1 expression, thereby implicating a mechanism by which PHC may exert its protective effects against LPS-induced pulmonary microvascular endothelial cell injury.

  6. Lipopolysaccharide-induced expression of cell surface receptors and cell activation of neutrophils and monocytes in whole human blood

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    N.E. Gomes

    2010-09-01

    Full Text Available Lipopolysaccharide (LPS activates neutrophils and monocytes, inducing a wide array of biological activities. LPS rough (R and smooth (S forms signal through Toll-like receptor 4 (TLR4, but differ in their requirement for CD14. Since the R-form LPS can interact with TLR4 independent of CD14 and the differential expression of CD14 on neutrophils and monocytes, we used the S-form LPS from Salmonella abortus equi and the R-form LPS from Salmonella minnesota mutants to evaluate LPS-induced activation of human neutrophils and monocytes in whole blood from healthy volunteers. Expression of cell surface receptors and reactive oxygen species (ROS and nitric oxide (NO generation were measured by flow cytometry in whole blood monocytes and neutrophils. The oxidative burst was quantified by measuring the oxidation of 2',7'-dichlorofluorescein diacetate and the NO production was quantified by measuring the oxidation of 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate. A small increase of TLR4 expression by monocytes was observed after 6 h of LPS stimulation. Monocyte CD14 modulation by LPS was biphasic, with an initial 30% increase followed by a 40% decrease in expression after 6 h of incubation. Expression of CD11b was rapidly up-regulated, doubling after 5 min on monocytes, while down-regulation of CXCR2 was observed on neutrophils, reaching a 50% reduction after 6 h. LPS induced low production of ROS and NO. This study shows a complex LPS-induced cell surface receptor modulation on human monocytes and neutrophils, with up- and down-regulation depending on the receptor. R- and S-form LPS activate human neutrophils similarly, despite the low CD14 expression, if the stimulation occurs in whole blood.

  7. Effect of penehyclidine hydrochloride on β-arrestin-1 expression in lipopolysaccharide-induced human pulmonary microvascular endothelial cells

    International Nuclear Information System (INIS)

    Zhan, J.; Xiao, F.; Zhang, Z.Z.; Wang, Y.P.; Chen, K.; Wang, Y.L.

    2013-01-01

    β-arrestins are expressed proteins that were first described, and are well-known, as negative regulators of G protein-coupled receptor signaling. Penehyclidine hydrochloride (PHC) is a new anti-cholinergic drug that can inhibit biomembrane lipid peroxidation, and decrease cytokines and oxyradicals. However, to date, no reports on the effects of PHC on β-arrestin-1 in cells have been published. The aim of this study was to investigate the effect of PHC on β-arrestin-1 expression in lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cells (HPMEC). Cultured HPMEC were pretreated with PHC, followed by LPS treatment. Muscarinic receptor mRNAs were assayed by real-time quantitative PCR. Cell viability was assayed by the methyl thiazolyl tetrazolium (MTT) conversion test. The dose and time effects of PHC on β-arrestin-1 expression in LPS-induced HPMEC were determined by Western blot analysis. Cell malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were measured. It was found that the M 3 receptor was the one most highly expressed, and was activated 5 min after LPS challenge. Furthermore, 2 μg/mL PHC significantly upregulated expression of β-arrestin-1 within 10 to 15 min. Compared with the control group, MDA levels in cells were remarkably increased and SOD activities were significantly decreased in LPS pretreated cells, while PHC markedly decreased MDA levels and increased SOD activities. We conclude that PHC attenuated ROS injury by upregulating β-arrestin-1 expression, thereby implicating a mechanism by which PHC may exert its protective effects against LPS-induced pulmonary microvascular endothelial cell injury

  8. Multiple sensors control reciprocal expression of Pseudomonas aeruginosa regulatory RNA and virulence genes

    DEFF Research Database (Denmark)

    Ventre, I.; Goodman, A.L.; Vallet-Gely, I.

    2006-01-01

    The opportunistic pathogen Pseudomonas aeruginosa is responsible for a wide range of acute and chronic infections. The transition to chronic infections is accompanied by physiological changes in the bacteria favoring formation of biofilm communities. Here we report the identification of LadS, a h...

  9. Expression of macrophage migration inhibitory factor and CD74 in the inner ear and middle ear in lipopolysaccharide-induced otitis media.

    Science.gov (United States)

    Ishihara, Hisashi; Kariya, Shin; Okano, Mitsuhiro; Zhao, Pengfei; Maeda, Yukihide; Nishizaki, Kazunori

    2016-10-01

    Significant expression of macrophage migration inhibitory factor and its receptor (CD74) was observed in both the middle ear and inner ear in experimental otitis media in mice. Modulation of macrophage migration inhibitory factor and its signaling pathway might be useful in the management of inner ear inflammation due to otitis media. Inner ear dysfunction secondary to otitis media has been reported. However, the specific mechanisms involved are not clearly understood. The aim of this study is to investigate the expression of macrophage migration inhibitory factor and CD74 in the middle ear and inner ear in lipopolysaccharide-induced otitis media. BALB/c mice received a transtympanic injection of either lipopolysaccharide or phosphate-buffered saline (PBS). The mice were sacrificed 24 h after injection, and temporal bones were processed for polymerase chain reaction (PCR) analysis, histologic examination, and immunohistochemistry. PCR examination revealed that the lipopolysaccharide-injected mice showed a significant up-regulation of macrophage migration inhibitory factor in both the middle ear and inner ear as compared with the PBS-injected control mice. The immunohistochemical study showed positive reactions for macrophage migration inhibitory factor and CD74 in infiltrating inflammatory cells, middle ear mucosa, and inner ear in the lipopolysaccharide-injected mice.

  10. Lipopolysaccharide increases Na(+),K(+)-pump, but not ENaC, expression in guinea-pig airway epithelium.

    Science.gov (United States)

    Dodrill, Michael W; Beezhold, Donald H; Meighan, Terence; Kashon, Michael L; Fedan, Jeffrey S

    2011-01-25

    Earlier, we found in functional experiments that lipopolysaccharide (LPS; 4mg/kg; i.p.) hyperpolarized the epithelium by stimulating the transepithelial transport of Na(+) in guinea-pig tracheal epithelium. Epithelial sodium channel (ENaC) activity and Na(+),K(+)-pump activity were increased. In this study, we hypothesized that LPS increases the expression of ENaC and the Na(+),K(+)-pump in the epithelium and investigated the levels of transcription and protein abundance. Using qPCR, the effects of LPS on the transcription of αENaC, α(1) Na(+),K(+)-pump, COX-2, eNOS, iNOS, IL-1β, and TNF-α were measured at 3 and 18h. In the epithelium, LPS increased the transcription of COX-2, IL-1β, and, to a nonsignificant extent, TNF-α at 3h, but not at 18h. In alveolar macrophages, TNF-α, and, to a nonsignificant extent, COX-2 and IL-1β were up-regulated at 3h, but not at 18h. Even though LPS stimulated the transcription of some genes, αENaC and α(1) Na(+),K(+)-ATPase transcription were not affected. The expressions of α-, β-, and γ-ENaC and α(1) Na(+),K(+)-pump from the tracheal epithelium and kidney cortex/medulla were investigated by western blotting. All three ENaC subunits were detected as cleavage fragments, yet LPS had no effect on their expression. LPS increased the expression of the α(1) subunit and the α(1), α(2), and α(3) subunits, collectively, of the Na(+),K(+)-pump. Taken together, these data indicate that LPS increases Na(+) transport downstream of the genetic level, in part, by stimulating the expression of the Na(+),K(+)-pump. Published by Elsevier B.V.

  11. A framework to identify gene expression profiles in a model of inflammation induced by lipopolysaccharide after treatment with thalidomide

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    Paiva Renata T

    2012-06-01

    Full Text Available Abstract Background Thalidomide is an anti-inflammatory and anti-angiogenic drug currently used for the treatment of several diseases, including erythema nodosum leprosum, which occurs in patients with lepromatous leprosy. In this research, we use DNA microarray analysis to identify the impact of thalidomide on gene expression responses in human cells after lipopolysaccharide (LPS stimulation. We employed a two-stage framework. Initially, we identified 1584 altered genes in response to LPS. Modulation of this set of genes was then analyzed in the LPS stimulated cells treated with thalidomide. Results We identified 64 genes with altered expression induced by thalidomide using the rank product method. In addition, the lists of up-regulated and down-regulated genes were investigated by means of bioinformatics functional analysis, which allowed for the identification of biological processes affected by thalidomide. Confirmatory analysis was done in five of the identified genes using real time PCR. Conclusions The results showed some genes that can further our understanding of the biological mechanisms in the action of thalidomide. Of the five genes evaluated with real time PCR, three were down regulated and two were up regulated confirming the initial results of the microarray analysis.

  12. Development of stable Vibrio cholerae O1 Hikojima type vaccine strains co-expressing the Inaba and Ogawa lipopolysaccharide antigens.

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    Stefan L Karlsson

    Full Text Available We describe here the development of stable classical and El Tor V. cholerae O1 strains of the Hikojima serotype that co-express the Inaba and Ogawa antigens of O1 lipopolysaccharide (LPS. Mutation of the wbeT gene reduced LPS perosamine methylation and thereby gave only partial transformation into Ogawa LPS on the cell surface. The strains express approximately equal amounts of Inaba- and Ogawa-LPS antigens which are preserved after formalin-inactivation of the bacteria. Oral immunizations of both inbred and outbred mice with formalin-inactivated whole-cell vaccine preparations of these strains elicited strong intestinal IgA anti-LPS as well as serum vibriocidal antibody responses against both Inaba and Ogawa that were fully comparable to the responses induced by the licensed Dukoral vaccine. Passive protection studies in infant mice showed that immune sera raised against either of the novel Hikojima vaccine strains protected baby mice against infection with virulent strains of both serotypes. This study illustrates the power of using genetic manipulation to improve the properties of bacteria strains for use in killed whole-cell vaccines.

  13. COL-3, a chemically modified tetracycline, inhibits lipopolysaccharide-induced microglia activation and cytokine expression in the brain.

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    Rawan Abdulhameed Edan

    Full Text Available Microglia activation results in release of proinflammatory molecules including cytokines, which contribute to neuronal damage in the central nervous system (CNS if not controlled. Tetracycline antibiotics such as minocycline inhibit microglial activation and cytokine expression during CNS inflammation. In the present study we found that administration of chemically modified tetracycline-3 (COL-3, inhibits lipopolysaccharide (LPS-induced microglial and p38 MAPK activation, as well as the increase in TNF-α, but not IL-1β expression, in the brains of BALB/c mice. COL-3 has been described to have no antibacterial activity. We observed that COL-3 had no activity against a Gram-negative bacteria, Escherichia coli; however surprisingly, COL-3 had antibacterial activity against a Gram-positive bacteria Staphylococcus aureus, with a minimum inhibitory concentration of 1 mg/ml. Our data show that COL-3 has some antibacterial activity against S. aureus, inhibits LPS-induced neuroinflammation, and displays potential as a therapeutic agent for treatment of conditions involving CNS inflammation.

  14. [Study of signal transduction pathway in the expression of inflammatory factors stimulated by lipopolysaccharides from Porphyromonas endodontalis in osteoblasts].

    Science.gov (United States)

    Yang, Di; Qiu, Li-hong; Li, Ren; Li, Zi-mu; Li, Chen

    2010-04-01

    To quantify the interleukin (IL)-1beta mRNA and IL-6 mRNA expression induced by lipopolysaccharides ([PS) extracted from Porphyromonoas endodontalis (P. endodontalis) in osteoblasts, and to relate P. endodontalis LPS to the bone resorptive pathogenesis in the lesions of chronic apical periodontitis. MG63 cells was pretreated with PD98059 or SB203580 for 1 h and then treated with P. endodontolis LPS for 6 h. The expression of IL-1beta mRNA and IL-6 mRNA were detected by reverse transcription polymerase chain reaction (RT-PCR) technique. The production of IL-1beta mRNA induced by P. endodontalis LPS decreased in osteoblasts pretreated with PD98059. Both of the production of IL-1beta mRNA and JL-6 mRNA induced by P. endodontalis LPS decreased in osteoblasts pretreated with SB203580. The synthesis of IL-1beta mRNA stimulated by Pendodontalis LPS in MG63 probably occur via extracellular signal-regulated kinase (ERK) 1/2 and p38 mitogen activated protein kinase (MAPK) signal transduction system. The synthesis of IL-6 mRNA stimulated by P.endodontalis LPS in MG63 probahly occur via p38MAPK signal transduction system.

  15. [Effect of lipopolysaccharides extracted from Porphyromonas endodontalis on the expression of p38 and ERK1/2 in osteoblast].

    Science.gov (United States)

    Lv, You; Jia, Ge; Qiu, Li-hong; Bao, Mu-rong; Yu, Ya-qiong; Guo, Yan

    2012-08-01

    To investigate the effect of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of p38 and ERK1/2 in osteoblast. MC3T3-E1 cells were stimulated with 10 μg/mL P.e-LPS for 0,5,15,30,60,180 min. The phosphorylation of p38 and ERK1/2 was measured by Western blot. Statistical analysis was performed using one- way ANOVA and Dunnett t test with SPSS11.0 software package. 10 μg/mL LPS could significantly activate p38 MAPK. The peak of phosphorylated p38 was detected at 5 to 30 min(P<0.01) and returned to baseline within 60 min; the level of phosphorylated ERK1/2 increased after the stimulation of LPS for 5 min and reached maximum at 15 min (P<0.01) and declined after 30 min. P.e-LPS can induce the expression of p38 and ERK1/2 in osteoblast MC3T3-E1, which indicates that P.e-LPS may play an important role in osteoblast through p38 and ERK1/2.

  16. [Effect of CD-14 and toll like receptors on the expression of interleukin-6 induced by lipopolysaccharides of Porphyromonas endodontalis].

    Science.gov (United States)

    Jia, Ge; Qiu, Li-Hong; Li, Ren; Lü, You; Yu, Ya-Qiong; Zhong, Ming

    2011-09-01

    To evaluate the effect of cluster of differentiation 14 (CD-14) and Toll like receptors (TLR) on the expression of interleukin-6 (IL-6) mRNA induced by Porphyromonas endodontalis (Pe) lipopolysaccharides (LPS). MC3T3-E1 cells were treated with 10 mg/L Pe-LPS for different hours, and the cells uninvolved by anything as the blank group. The expression of IL-6 was detected by reverse transcription polymerse chain reaction (RT-PCR) and enzyme-liked immunosorbent assay (ELISA). The expression of CD-14, TLR-2 and TLR-4 mRNA was observed at different time point (0 - 24 h) by RT-PCR. The protein of CD-14, TLR-2 and TLR-4 was analyzed with a flow cytometer. MC3T3-E1 cells were pretreated with anti-CD-14, anti-TLR-2 and anti-TLR-4 antibody for 1 h, and then cells were stimulated with 10 mg/L Pe-LPS for 6 h. The expression of IL-6 mRNA was examined by RT-PCR. Statistical analysis was performed using one-way ANOVA Dunnett-t test with SPSS 11.0 software package. The IL-6 mRNA and proteins increased significantly after treatment with Pe-LPS. When MC3T3-E1 cells treated by Pe-LPS for 6 h, the expression of proteins soared from (11.696 ± 0.672) ng/L to (36.534 ± 0.574) ng/L (P < 0.01); In the control group, the CD-14 and TLR-4 mRNA are ambly-expression, and the ratios of CD-14 and TLR-4 positive cells were (39.038 ± 3.131)% and (11.438 ± 0.385)% respectively in MC3T3-E1. After treatment by Pe-LPS, the expression of CD-14 and TLR-4 mRNA increased significantly, and the ratios of CD-14 and TLR-4 positive cells markedly increased to (62.407 ± 1.800)% and (21.367 ± 2.271)%. TLR-2 expression did not change apparently after Pe-LPS treatment. The expression of IL-6 mRNA was partly inhibited by anti-CD-14 or anti-TLR-4 antibody, but not by TLR-2. Pe-LPS can induce the expression of IL-6 in osteoblast MC3T3-E1 through CD-14 and TLR-4, but not TLR-2.

  17. [Effects of lipopolysaccharides from various Porphyromonas on the expression of CD14 and TLRs in mouse osteoblast].

    Science.gov (United States)

    Jia, Ge; Xue, Ming; Li, Ren; Lv, You; Qiu, Li-hong

    2011-12-01

    To observe the effect of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) and Porphyromonas gingivals(P.g) on the expression of CD14 and TLRs in osteoblast. MC3T3-E1 cells were stimulated with 10μg/mL P.e-LPS and P.g-LPS. The change of CD14,TLR2 and TLR4 mRNA was observed at different time point (0,1,3,6,12,24h) using RT-PCR,and the expression of CD14,TLR2 and TLR4 protein was measured by flow cytometry at 24-hour. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS11.0 software package. MC3T3-E1 cells were stimulated with 10μg/mL P.e-LPS for 1h,the expression of CD14 and TLR4 mRNA increased significantly. There was no increase of TLR2 mRNA with stimulation of P.e-LPS. The CD14,TLR2 and TLR4 mRNA expression increased significantly after stimulation with 10μg/mL P.g-LPS. Flow cytometry showed that CD14 and TLR4 protein increased significantly after stimulation with 10μg/mL P.e-LPS. CD14,TLR2 and TLR4 protein increased significantly after treatment with 10μg/mL P.g-LPS. CD14,TLR4 receptors are involved in P.e-LPS effect and CD14,TLR2 and TLR4 receptors are involved in P.g-LPS effect in mouse osteoblast.

  18. Comparison of Gene Expression by Sheep and Human Blood Stimulated with the TLR4 Agonists Lipopolysaccharide and Monophosphoryl Lipid A.

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    Perenlei Enkhbaatar

    Full Text Available Animal models that mimic human biology are important for successful translation of basic science discoveries into the clinical practice. Recent studies in rodents have demonstrated the efficacy of TLR4 agonists as immunomodulators in models of infection. However, rodent models have been criticized for not mimicking important characteristics of the human immune response to microbial products. The goal of this study was to compare genomic responses of human and sheep blood to the TLR4 agonists lipopolysaccharide (LPS and monophosphoryl lipid A (MPLA.Venous blood, withdrawn from six healthy human adult volunteers (~ 28 years old and six healthy adult female sheep (~3 years old, was mixed with 30 μL of PBS, LPS (1μg/mL or MPLA (10μg/mL and incubated at room temperature for 90 minutes on a rolling rocker. After incubation, 2.5 mL of blood was transferred to Paxgene Blood RNA tubes. Gene expression analysis was performed using an Agilent Bioanalyzer with the RNA6000 Nano Lab Chip. Agilent gene expression microarrays were scanned with a G2565 Microarray Scanner. Differentially expressed genes were identified.11,431 human and 4,992 sheep probes were detected above background. Among them 1,029 human and 175 sheep genes were differentially expressed at a stringency of 1.5-fold change (p 1.5-fold changes in human samples. Genes of major inflammatory mediators, such as IL-1, IL-6 and IL-8, TNF alpha, NF-kappaB, ETS2, PTGS2, PTX3, CXCL16, KYNU, and CLEC4E were similarly (>2-fold upregulated by LPS and MPLA in both species.The genomic responses of peripheral blood to LPS and MPLA in sheep are quite similar to those observed in humans, supporting the use of the ovine model for translational studies that mimic human inflammatory diseases and the study of TLR-based immunomodulators.

  19. Expression of Pseudomonas aeruginosa transposable phages in Pseudomonas putida cells. I. Establishment of lysogeny and lytic growth efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Gorbunova, S.A.; Yanenko, A.S.; Akhverdyan, V.Z.; Reulets, M.A.; Krylov, V.N.

    1986-03-01

    Expression of the genomes of Pseudomonas aeruginosa transposable phages (TP) in the cells of a heterologous host, P. putida PpGl, was studied. A high efficiency of TP lytic growth in PpGl cells was obtained both after zygotic induction following RP4::TP plasmid transfer and after thermoinduction of PpGl cells lysogenic for thermoinducible prophage D3112cts15. Characteristic for PpGl cells was a high TP yield (20-25 phage D3112cts15 particles per cell), which was evidence of a high level of TP transposition in cells of this species. The frequency of RP4::TP transfer into PpGl and PA01 cells was equal, but the lysogeny detection rat was somewhat lower in PpGl. Pseudomonas aeruginosa TP can integrate into the PpGl chromosome, producing inducible lysogens. The presence of RP4 is not necessary for the expression of the TP genome in PpGl cells. The D3112cts15 TP may be used for interspecific transduction of plasmids and chromosomal markers.

  20. Expression of Pseudomonas aeruginosa transposable phages in Pseudomonas putida cells. I. Establishment of lysogeny and lytic growth efficiency

    International Nuclear Information System (INIS)

    Gorbunova, S.A.; Yanenko, A.S.; Akhverdyan, V.Z.; Reulets, M.A.; Krylov, V.N.

    1986-01-01

    Expression of the genomes of Pseudomonas aeruginosa transposable phages (TP) in the cells of a heterologous host, P. putida PpGl, was studied. A high efficiency of TP lytic growth in PpGl cells was obtained both after zygotic induction following RP4::TP plasmid transfer and after thermoinduction of PpGl cells lysogenic for thermoinducible prophage D3112cts15. Characteristic for PpGl cells was a high TP yield (20-25 phage D3112cts15 particles per cell), which was evidence of a high level of TP transposition in cells of this species. The frequency of RP4::TP transfer into PpGl and PA01 cells was equal, but the lysogeny detection rat was somewhat lower in PpGl. Pseudomonas aeruginosa TP can integrate into the PpGl chromosome, producing inducible lysogens. The presence of RP4 is not necessary for the expression of the TP genome in PpGl cells. The D3112cts15 TP may be used for interspecific transduction of plasmids and chromosomal markers

  1. Expression of Toll-Like Receptor 2 in Glomerular Endothelial Cells and Promotion of Diabetic Nephropathy by Porphyromonas gingivalis Lipopolysaccharide

    Science.gov (United States)

    Hatakeyama, Yuji; Ishikawa, Hiroyuki; Tsuruga, Eichi

    2014-01-01

    The toll-like receptor (TLR) has been suggested as a candidate cause for diabetic nephropathy. Recently, we have reported the TLR4 expression in diabetic mouse glomerular endothelium. The study here investigates the effects of the periodontal pathogen Porphyromonas gingivalis lipopolysaccharide (LPS) which is a ligand for TLR2 and TLR4 in diabetic nephropathy. In laser-scanning microscopy of glomeruli of streptozotocin- and a high fat diet feed-induced type I and type II diabetic mice, TLR2 localized on the glomerular endothelium and proximal tubule epithelium. The TLR2 mRNA was detected in diabetic mouse glomeruli by in situ hybridization and in real-time PCR of the renal cortex, the TLR2 mRNA amounts were larger in diabetic mice than in non-diabetic mice. All diabetic mice subjected to repeated LPS administrations died within the survival period of all of the diabetic mice not administered LPS and of all of the non-diabetic LPS-administered mice. The LPS administration promoted the production of urinary protein, the accumulation of type I collagen in the glomeruli, and the increases in IL-6, TNF-α, and TGF-β in the renal cortex of the glomeruli of the diabetic mice. It is thought that blood TLR ligands like Porphyromonas gingivalis LPS induce the glomerular endothelium to produce cytokines which aid glomerulosclerosis. Periodontitis may promote diabetic nephropathy. PMID:24835775

  2. Effect of Egg White Combined with Chalcanthite on Lipopolysaccharide induced Inflammatory Cytokine Expression in RAW 264.7 cells

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    Choi Eun-A

    2012-03-01

    Full Text Available Historically, mineral compound herbal medicines have long been used in treatments of immune-related diseases in Korea, China and other Asian countries. In this study, we inv-estigated the anti-inflammatory effect of egg white combined with chalcanthite (IS4 on lipopolysaccharide (LPS-stimulated RAW 264.7 cells. RAW 264.7 cells cultured with LPS and various con-centrations of IS4 were analyzed to determine the production of pro-inflammatory cytokines and mediators by using enzyme-linked immune sorbent assays (ELISAs. IS4 concentration inhibited the production of interleukin-1beta (IL-1β, interleukin-6 (IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF induced by LPS. IS4 at high concentrations (25 and 50`㎍/ml inhibited, in concentration-dependent manner, the expression of tumor necrosis factor-alpha (TNF–α stimulated by LPS. IS4 has shown an anti-inflammatory effect in RAW 264.7 cells.

  3. Gene expression profiling of liver from dairy cows treated intra-mammary with lipopolysaccharide

    DEFF Research Database (Denmark)

    Jiang, Li; Sørensen, Peter; Røntved, Christine

    2008-01-01

    Liver plays a profound role in the acute phase response (APR) observed in the early phase of acute bovine mastitis caused by Escherichia coli (E. coli). To gain an insight into the genes and pathways involved in hepatic APR of dairy cows we performed a global gene expression analysis of liver...... also seemed to participate in APR. CONCLUSIONS: Performing global gene expression analysis on liver tissue from IM LPS treated cows verified that the liver plays a major role in the APR of E. coli mastitis, and that the bovine hepatic APR follows the same pattern as other mammals when...

  4. Dynamics of Protein Phosphatase Gene Expression in Corbicula fluminea Exposed to Microcystin-LR and to Toxic Microcystis aeruginosa Cells

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    Vitor Vasconcelos

    2011-12-01

    Full Text Available This study investigated the in vivo effects of microcystins on gene expression of several phosphoprotein phosphatases (PPP in the freshwater clam Corbicula fluminea with two different exposure scenarios. Clams were exposed for 96 h to 5 µg L−1 of dissolved microcystin-LR and the relative changes of gene expression of three different types of PPP (PPP1, 2 and 4 were analyzed by quantitative real-time PCR. The results showed a significant induction of PPP2 gene expression in the visceral mass. In contrast, the cyanotoxin did not cause any significant changes on PPP1 and PPP4 gene expression. Based on these results, we studied alterations in transcriptional patterns in parallel with enzymatic activity of C. fluminea for PPP2, induced by a Microcystis aeruginosa toxic strain (1 × 105 cells cm−3 during 96 h. The relative changes of gene expression and enzyme activity in visceral mass were analyzed by quantitative real-time PCR and colorimetric assays respectively. The clams exhibited a significant reduction of PPP2 activity with a concomitant enhancement of gene expression. Considering all the results we can conclude that the exposure to an ecologically relevant concentration of pure or intracellular microcystins (-LR promoted an in vivo effect on PPP2 gene expression in C. fluminea.

  5. Effect of Negative Pressure on Proliferation, Virulence Factor Secretion, Biofilm Formation, and Virulence-Regulated Gene Expression of Pseudomonas aeruginosa In Vitro

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    Guo-Qi Wang

    2016-01-01

    Full Text Available Objective. To investigate the effect of negative pressure conditions induced by NPWT on P. aeruginosa. Methods. P. aeruginosa was cultured in a Luria–Bertani medium at negative pressure of −125 mmHg for 24 h in the experimental group and at atmospheric pressure in the control group. The diameters of the colonies of P. aeruginosa were measured after 24 h. ELISA kit, orcinol method, and elastin-Congo red assay were used to quantify the virulence factors. Biofilm formation was observed by staining with Alexa Fluor® 647 conjugate of concanavalin A (Con A. Virulence-regulated genes were determined by quantitative RT-PCR. Results. As compared with the control group, growth of P. aeruginosa was inhibited by negative pressure. The colony size under negative pressure was significantly smaller in the experimental group than that in the controls (p<0.01. Besides, reductions in the total amount of virulence factors were observed in the negative pressure group, including exotoxin A, rhamnolipid, and elastase. RT-PCR results revealed a significant inhibition in the expression level of virulence-regulated genes. Conclusion. Negative pressure could significantly inhibit the growth of P. aeruginosa. It led to a decrease in the virulence factor secretion, biofilm formation, and a reduction in the expression level of virulence-regulated genes.

  6. [Effect of lipopolysaccharides from Porphyromonas endodontalis on the expression of macrophage colony stimulating factor in mouse osteoblasts].

    Science.gov (United States)

    Yu, Yaqiong; Qiu, Lihong; Guo, Jiajie; Qu, Liu; Xu, Liya; Zhong, Ming

    2014-09-01

    To investigate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of macrophage colony stimulating factor (M-CSF) mRNA and protein in MC3T3-E1 cells and the role of nucler factor-κB (NF-κB) in the process. MC3T3-E1 cells were treated with different concentrations of Pe-LPS (0-50 mg/L) and 10 mg/L Pe-LPS for different hours (0-24 h). The expression of M-CSF mRNA and protein was detected by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunoadsordent assay (ELISA). The cells untreated by Pe-LPS served as control. The expression of M- CSF mRNA and protein was also detected in 10 mg/L Pe- LPS treated MC3T3-E1 cells after pretreated with BAY 11-7082 for 1 h, a special NF-κB inhibitor. The groups were divided as follows, control group, BAY group (10 µmol/L BAY 11-7082 treated alone MC3T3-E1 cells), Pe-LPS group (10 mg/L Pe-LPS stimulated MC3T3-E1 cells for 6 h), BAY combine with Pe-LPS group (10 µmol/L BAY 11-7082 pretreated cells for 1 h and 10 mg/L of Pe-LPS stimulated MC3T3-E1 cells for 6 h). The level of M- CSF mRNA and protein increased significantly after treatment with different concentrations of Pe-LPS (0-50 mg/L), which indicated that Pe-LPS induced osteoblasts to express M-CSF mRNA and protein in dose dependent manners. The expression of M-CSF protein increased from (35 ± 2) ng/L (control group) to (170 ± 8) ng/L (50 mg/L group). Maximal induction of M-CSF mRNA expression was found in the MC3T3- E1 cells treated with 10 mg/L Pe-LPS for 6 h. After 6 h, the expression of M-CSF mRNA decreased gradually. The expression of M-CSF protein also increased with the treatment of 10 mg/L Pe-LPS for 10 h [(122 ± 4) ng/L]. After 10 h, the expression of M-CSF protein decreased gradually. The mRNA and proteins of M-CSF decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h. There was no significant difference between BAY group and the control. Pe-LPS may induce

  7. Expression of lung vascular and airway ICAM-1 after exposure to bacterial lipopolysaccharide

    DEFF Research Database (Denmark)

    Beck-Schimmer, B; Schimmer, R C; Warner, R L

    1997-01-01

    model. This increase was reduced by 81% after treatment of animals with anti-tumor necrosis factor-alpha (TNF-alpha) antibody and by 37% after treatment with anti-interleukin-1 (IL-1) antibody. The same interventions reduced whole-lung ICAM-1 protein by 85% and 25%, respectively. The studies were...... extended to assess the locale in lung of ICAM-I upregulation. Lung vascular ICAM-1 content, which was assessed by vascular fixation of [125I]anti-ICAM-1, rose 4-fold after airway instillation of LPS. This rise was also TNF-alpha-dependent. Under the same experimental conditions, fixation of [125I...... lavage fluids (BALFs) of animals after intratracheal instillation of LPS. Retrieved alveolar macrophages showed a small, significant, and transient increase in surface expression of ICAM-1. These data indicate, at the very least, a dual compartmentalized (vascular and airway) upregulation of ICAM-1 after...

  8. Brain microvascular pericytes are immunoactive in culture: cytokine, chemokine, nitric oxide, and LRP-1 expression in response to lipopolysaccharide

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    Erickson Michelle A

    2011-10-01

    Full Text Available Abstract Background Brain microvascular pericytes are important constituents of the neurovascular unit. These cells are physically the closest cells to the microvascular endothelial cells in brain capillaries. They significantly contribute to the induction and maintenance of the barrier functions of the blood-brain barrier. However, very little is known about their immune activities or their roles in neuroinflammation. Here, we focused on the immunological profile of brain pericytes in culture in the quiescent and immune-challenged state by studying their production of immune mediators such as nitric oxide (NO, cytokines, and chemokines. We also examined the effects of immune challenge on pericyte expression of low density lipoprotein receptor-related protein-1 (LRP-1, a protein involved in the processing of amyloid precursor protein and the brain-to-blood efflux of amyloid-β peptide. Methods Supernatants were collected from primary cultures of mouse brain pericytes. Release of nitric oxide (NO was measured by the Griess reaction and the level of S-nitrosylation of pericyte proteins measured with a modified "biotin-switch" method. Specific mitogen-activated protein kinase (MAPK pathway inhibitors were used to determine involvement of these pathways on NO production. Cytokines and chemokines were analyzed by multianalyte technology. The expression of both subunits of LRP-1 was analyzed by western blot. Results Lipopolysaccharide (LPS induced release of NO by pericytes in a dose-dependent manner that was mediated through MAPK pathways. Nitrative stress resulted in S-nitrosylation of cellular proteins. Eighteen of twenty-three cytokines measured were released constitutively by pericytes or with stimulation by LPS, including interleukin (IL-12, IL-13, IL-9, IL-10, granulocyte-colony stimulating factor, granulocyte macrophage-colony stimulating factor, eotaxin, chemokine (C-C motif ligand (CCL-3, and CCL-4. Pericyte expressions of both subunits of

  9. Reduced intracellular c-di-GMP content increases expression of quorum sensing-regulated genes in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Chua, Song Lin; Liu, Yang; Li, Yingying

    2017-01-01

    Cyclic-di-GMP (c-di-GMP) is an intracellular secondary messenger which controls the biofilm life cycle in many bacterial species. High intracellular c-di-GMP content enhances biofilm formation via the reduction of motility and production of biofilm matrix, while low c-di-GMP content in biofilm...... cells leads to increased motility and biofilm dispersal. While the effect of high c-di-GMP levels on bacterial lifestyles is well studied, the physiology of cells at low c-di-GMP levels remains unclear. Here, we showed that Pseudomonas aeruginosa cells with high and low intracellular c-di-GMP contents...... possessed distinct transcriptome profiles. There were 535 genes being upregulated and 432 genes downregulated in cells with low c-di-GMP, as compared to cells with high c-di-GMP. Interestingly, both rhl and pqs quorum-sensing (QS) operons were expressed at higher levels in cells with low intracellular c-di-GMP...

  10. New insights about antibiotic production by Pseudomonas aeruginosa: a gene expression analysis

    Science.gov (United States)

    Gionco, Bárbara; Tavares, Eliandro R.; de Oliveira, Admilton G.; Yamada-Ogatta, Sueli F.; do Carmo, Anderson O.; Pereira, Ulisses de Pádua; Chideroli, Roberta T.; Simionato, Ane S.; Navarro, Miguel O. P.; Chryssafidis, Andreas L.; Andrade, Galdino

    2017-09-01

    The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified twelve upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

  11. New Insights about Antibiotic Production by Pseudomonas aeruginosa: A Gene Expression Analysis

    Directory of Open Access Journals (Sweden)

    Bárbara Gionco

    2017-09-01

    Full Text Available The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified 12 upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and we suggesting that may involve in the biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

  12. The consistent differential expression of genetic pathways following exposure of an industrial Pseudomonas aeruginosa strain to preservatives and a laundry detergent formulation

    Science.gov (United States)

    Amézquita, Alejandro; Le Marc, Yvan; Bull, Matthew J; Connor, Thomas R; Mahenthiralingam, Eshwar

    2018-01-01

    Abstract Pseudomonas aeruginosa is a common contaminant associated with product recalls in the home and personal care industry. Preservation systems are used to prevent spoilage and protect consumers, but greater knowledge is needed of preservative resistance mechanisms used by P. aeruginosa contaminants. We aimed to identify genetic pathways associated with preservative exposure by using an industrial P. aeruginosa strain and implementing RNA-Seq to understand gene expression changes in response to industry relevant conditions. The consistent differential expression of five genetic pathways during exposure to multiple industrial growth conditions associated with benzisothiazolone (BIT) and phenoxyethanol (POE) preservatives, and a laundry detergent (LD) formulation, was observed. A MexPQ-OpmE Resistance Nodulation Division efflux pump system was commonly upregulated in response to POE, a combination of BIT and POE, and LD together with BIT. In response to all industry conditions, a putative sialic acid transporter and isoprenoid biosynthesis gnyRDBHAL operon demonstrated consistent upregulation. Two operons phnBA and pqsEDCBA involved in Pseudomonas quinolone signaling production and quorum-sensing were also consistently downregulated during exposure to all the industry conditions. The ability to identify consistently differentially expressed genetic pathways in P. aeruginosa can inform the development of future targeted preservation systems that maintain product safety and minimise resistance development. PMID:29548026

  13. Natural isothiocyanates express antimicrobial activity against developing and mature biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Kaiser, Stefan J; Mutters, Nico T; Blessing, Brigitte; Günther, Frank

    2017-06-01

    The antimicrobial properties of natural isothiocyanates (ITCs) found in plants such as nasturtium (Tropaeolum majus) and horseradish (Armoracia rusticana), and the need of new chemotherapeutic options for treatment of infections caused by multidrug-resistant and biofilm-forming Gram-negative bacteria such as Pseudomonas aeruginosa (Pa), led us to evaluate the effects of three major ITCs, allylisothiocyanate (AITC), benzylisothiocyanate (BITC), and phenylethyl-isothiocyanate (PEITC), and a mixture (ITCM) adapted to the ITC composition after release of active components out of natural sources. Out of 105Pa isolates 27 isolates with increased biofilm formation were selected for testing. The effects of ITCs on Pa were evaluated regarding (1) planktonic bacterial proliferation, (2) biofilm formation, (3) metabolic activity in mature biofilms, and (4) synergism of ITCs and antibiotics. (1) Each ITC had anti-Pa activity. Mean minimum inhibitory concentrations (MICs) were (μg/ml, mean±standard deviation): AITC 103±6.9; BITC, 2145±249; PEITC 29,423±1652; and ITCM, 140±5. (2) Treating bacteria with PEITC and ITCM in concentrations below the MIC significantly inhibited biofilm formation. Particularly, ITCM reduced biofilm mass and bacterial proliferation. (3) ITCs significantly inhibited metabolic activity in mature biofilms. (4) Combining ITCs with meropenem synergistically increased antimicrobial efficacy on Pa biofilms. ITCs represent a promising group of natural anti-infective compounds with activity against Pa biofilms. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Human Tear Fluid Reduces Culturability of Contact Lens Associated Pseudomonas aeruginosa Biofilms but Induces Expression of the Virulence Associated Type III Secretion System

    Science.gov (United States)

    Wu, Yvonne T.; Tam, Connie; Zhu, Lucia S.; Evans, David J.; Fleiszig, Suzanne M. J.

    2017-01-01

    Purpose The type III secretion system (T3SS) is a significant virulence determinant for Pseudomonas aeruginosa. Using a rodent model, we found that contact lens (CL)-related corneal infections were associated with lens surface biofilms. Here, we studied the impact of human tear fluid on CL-associated biofilm growth and T3SS expression. Methods P. aeruginosa biofilms were formed on contact lenses for up to 7 days with or without human tear fluid, then exposed to tear fluid for 5 or 24 h. Biofilms were imaged using confocal microscopy. Bacterial culturability was quantified by viable counts, and T3SS gene expression measured by RT-qPCR. Controls included trypticase soy broth, PBS and planktonic bacteria. Results With or without tear fluid, biofilms grew to ~108 cfu viable bacteria by 24 h. Exposing biofilms to tear fluid after they had formed without it on lenses reduced bacterial culturability ~180-fold (pbacteria [5.46 ± 0.24-fold for T3SS transcriptional activitor exsA (p=.02), and 3.76 ± 0.36-fold for T3SS effector toxin exoS (p=.01)]. Tear fluid further enhanced exsA and exoS expression in CL-grown biofilms, but not planktonic bacteria, by 2.09 ± 0.38-fold (p = 0.04) and 1.89 ± 0.26-fold (p<.001), respectively. Conclusions Considering the pivitol role of the T3SS in P. aeruginosa infections, its induction in CL-grown P. aeruginosa biofilms by tear fluid might contribute to the pathogenesis of CL-related P. aeruginosa keratitis. PMID:27670247

  15. In-Vivo Expression Profiling of Pseudomonas aeruginosa Infections Reveals Niche-Specific and Strain-Independent Transcriptional Programs

    NARCIS (Netherlands)

    Bielecki, P.; Puchalka, J.; Wos-Oxley, M.L.; Martins Dos Santos, V.A.P.

    2011-01-01

    Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics.

  16. Colistin-Resistant, Lipopolysaccharide-Deficient Acinetobacter baumannii Responds to Lipopolysaccharide Loss through Increased Expression of Genes Involved in the Synthesis and Transport of Lipoproteins, Phospholipids, and Poly-β-1,6-N-Acetylglucosamine

    Science.gov (United States)

    Henry, Rebekah; Vithanage, Nuwan; Harrison, Paul; Seemann, Torsten; Coutts, Scott; Moffatt, Jennifer H.; Nation, Roger L.; Li, Jian; Harper, Marina; Adler, Ben

    2012-01-01

    We recently demonstrated that colistin resistance in Acinetobacter baumannii can result from mutational inactivation of genes essential for lipid A biosynthesis (Moffatt JH, et al., Antimicrob. Agents Chemother. 54:4971–4977). Consequently, strains harboring these mutations are unable to produce the major Gram-negative bacterial surface component, lipopolysaccharide (LPS). To understand how A. baumannii compensates for the lack of LPS, we compared the transcriptional profile of the A. baumannii type strain ATCC 19606 to that of an isogenic, LPS-deficient, lpxA mutant strain. The analysis of the expression profiles indicated that the LPS-deficient strain showed increased expression of many genes involved in cell envelope and membrane biogenesis. In particular, upregulated genes included those involved in the Lol lipoprotein transport system and the Mla-retrograde phospholipid transport system. In addition, genes involved in the synthesis and transport of poly-β-1,6-N-acetylglucosamine (PNAG) also were upregulated, and a corresponding increase in PNAG production was observed. The LPS-deficient strain also exhibited the reduced expression of genes predicted to encode the fimbrial subunit FimA and a type VI secretion system (T6SS). The reduced expression of genes involved in T6SS correlated with the detection of the T6SS-effector protein AssC in culture supernatants of the A. baumannii wild-type strain but not in the LPS-deficient strain. Taken together, these data show that, in response to total LPS loss, A. baumannii alters the expression of critical transport and biosynthesis systems associated with modulating the composition and structure of the bacterial surface. PMID:22024825

  17. Colistin-resistant, lipopolysaccharide-deficient Acinetobacter baumannii responds to lipopolysaccharide loss through increased expression of genes involved in the synthesis and transport of lipoproteins, phospholipids, and poly-β-1,6-N-acetylglucosamine.

    Science.gov (United States)

    Henry, Rebekah; Vithanage, Nuwan; Harrison, Paul; Seemann, Torsten; Coutts, Scott; Moffatt, Jennifer H; Nation, Roger L; Li, Jian; Harper, Marina; Adler, Ben; Boyce, John D

    2012-01-01

    We recently demonstrated that colistin resistance in Acinetobacter baumannii can result from mutational inactivation of genes essential for lipid A biosynthesis (Moffatt JH, et al., Antimicrob. Agents Chemother. 54:4971-4977). Consequently, strains harboring these mutations are unable to produce the major Gram-negative bacterial surface component, lipopolysaccharide (LPS). To understand how A. baumannii compensates for the lack of LPS, we compared the transcriptional profile of the A. baumannii type strain ATCC 19606 to that of an isogenic, LPS-deficient, lpxA mutant strain. The analysis of the expression profiles indicated that the LPS-deficient strain showed increased expression of many genes involved in cell envelope and membrane biogenesis. In particular, upregulated genes included those involved in the Lol lipoprotein transport system and the Mla-retrograde phospholipid transport system. In addition, genes involved in the synthesis and transport of poly-β-1,6-N-acetylglucosamine (PNAG) also were upregulated, and a corresponding increase in PNAG production was observed. The LPS-deficient strain also exhibited the reduced expression of genes predicted to encode the fimbrial subunit FimA and a type VI secretion system (T6SS). The reduced expression of genes involved in T6SS correlated with the detection of the T6SS-effector protein AssC in culture supernatants of the A. baumannii wild-type strain but not in the LPS-deficient strain. Taken together, these data show that, in response to total LPS loss, A. baumannii alters the expression of critical transport and biosynthesis systems associated with modulating the composition and structure of the bacterial surface.

  18. Monocytes can be induced by lipopolysaccharide-triggered T lymphocytes to express functional factor VII/VIIa protease activity

    OpenAIRE

    1984-01-01

    In the present study we demonstrate that human monocytes can be induced by the model stimulus, lipopolysaccharide (LPS), to produce and assemble on their surface functional Factor VII/VIIa. This protease was not induced in relatively purified monocytes alone following exposure to LPS; but was induced in the presence of Leu-3a positive helper/inducer T cells. The Factor VII/VIIa protease activity represented 35-40% of the potential initiating activity for the extrinsic coagulation pathway and ...

  19. Suppression of the lipopolysaccharide-induced expression of MARCKS-related protein (MRP) affects transmigration in activated RAW264.7 cells.

    Science.gov (United States)

    Chun, Kwang-Rok; Bae, Eun Mi; Kim, Jae-Kwan; Suk, Kyoungho; Lee, Won-Ha

    2009-01-01

    The molecular action mechanism of MRP, one of the protein kinase C (PKC) substrates, has been under intense investigation, but reports on its role in macrophage function remain controversial. The treatment of macrophage cell lines with bacterial lipopolysaccharide (LPS) induced a high level of MRP expression suggesting that MRP plays a role in the function of activated macrophages. In order to investigate the role of MRP in activated RAW264.7 cells, we stably transfected MRP-specific shRNA expression constructs and tested for alterations in macrophage-related functions. The down-regulation of MRP expression resulted in a marked reduction in chemotaxis toward MCP-1 or extracellular matrix proteins. Furthermore, pharmacological inhibitors of PKC significantly inhibited the chemotaxis in RAW264.7 cells. These data reveals the pivotal role of MRP in the transmigration of activated RAW264.7 cells.

  20. Ellagic acid derivatives from Terminalia chebula Retz. downregulate the expression of quorum sensing genes to attenuate Pseudomonas aeruginosa PAO1 virulence.

    Directory of Open Access Journals (Sweden)

    Sajal Sarabhai

    Full Text Available BACKGROUND: Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors. METHODS AND RESULTS: Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136. Bioactive fraction (F7, obtained by fractionation of methanol extract using Sephadex LH20, showed significant reduction (p<0.001 in QS regulated production of extracellular virulence factors in P. aeruginosa PAO1. Biofilm formation and alginate were significantly (p<0.05 reduced with enhanced (20% susceptibility to tobramycin. Real Time PCR of F7 treated P. aeruginosa showed down regulation of autoinducer synthase (lasI and rhlI and their cognate receptor (lasR and rhlR genes by 89, 90, 90 and 93%, respectively. Electrospray Ionization Mass Spectrometry also showed 90 and 64% reduction in the production of 3-oxo-C(12HSL and C(4HSL after treatment. Decrease in AHLs as one of the mechanisms of quorum quenching by F7 was supported by the reversal of inhibited swarming motility in F7-treated P. aeruginosa PAO1 on addition of C(4HSL. F7 also showed antagonistic activity against 3-oxo-C(12HSL-dependent QS in E. coli bioreporter. C. elegans fed on F7-treated P. aeruginosa showed enhanced survival with LT50 increasing from 24 to 72 h. LC-ESI-MS of F7 revealed the presence of ellagic acid derivatives responsible for anti QS activity in T. chebula extract. CONCLUSIONS: This is the first report on anti QS activity of T. chebula fruit linked to EADs which down regulate the expression of lasIR and rhlIR genes with concomitant decrease in AHLs in P. aeruginosa PAO1 causing attenuation of its virulence factors

  1. 11-Hydroxy-β-steroid dehydrogenase gene expression in canine adipose tissue and adipocytes: stimulation by lipopolysaccharide and tumor necrosis factor α.

    Science.gov (United States)

    Ryan, V H; Trayhurn, P; Hunter, L; Morris, P J; German, A J

    2011-10-01

    The enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD-1) is expressed in a number of tissues in rodents and humans and is responsible for the reactivation of inert cortisone into cortisol. Its gene expression and activity are increased in white adipose tissue (WAT) from obese humans and may contribute to the adverse metabolic consequences of obesity and the metabolic syndrome. The extent to which 11β-HSD-1 contributes to adipose tissue function in dogs is unknown; the aim of the present study was to examine 11β-HSD-1 gene expression and its regulation by proinflammatory and anti-inflammatory agents in canine adipocytes. Real-time PCR was used to examine the expression of 11β-HSD-1 in canine adipose tissue and canine adipocytes differentiated in culture. The mRNA encoding 11β-HSD-1 was identified in all the major WAT depots in dogs and also in liver, kidney, and spleen. Quantification by real-time PCR showed that 11β-HSD-1 mRNA was least in perirenal and falciform depots and greatest in subcutaneous, omental, and gonadal depots. Greater expression was seen in the omental depot in female than in male dogs (P=0.05). Gene expression for 11β-HSD-1 was also seen in adipocytes, from both subcutaneous and visceral depots, differentiated in culture; expression was evident throughout differentiation but was generally greatest in preadipocytes and during early differentiation, declining as cells progressed to maturity. The inflammatory mediators lipopolysaccharide and tumor necrosis factor α had a main stimulatory effect on 11β-HSD-1 gene expression in canine subcutaneous adipocytes, but IL-6 had no significant effect. Treatment with dexamethasone resulted in a significant time- and dose-dependent increase in 11β-HSD-1 gene expression, with greatest effects seen at 24 h (2 nM: approximately 4-fold; 20 nM: approximately 14-fold; P=0.010 for both). When subcutaneous adipocytes were treated with the peroxisome proliferator activated receptor γ agonist rosiglitazone

  2. In vivo Host Environment Alters Pseudomonas aeruginosa Susceptibility to Aminoglycoside Antibiotics

    Science.gov (United States)

    Pan, Xiaolei; Dong, Yuanyuan; Fan, Zheng; Liu, Chang; Xia, Bin; Shi, Jing; Bai, Fang; Jin, Yongxin; Cheng, Zhihui; Jin, Shouguang; Wu, Weihui

    2017-01-01

    During host infection, Pseudomonas aeruginosa coordinately regulates the expression of numerous genes to adapt to the host environment while counteracting host clearance mechanisms. As infected patients take antibiotics, the invading bacteria encounter antibiotics in the host milieu. P. aeruginosa is highly resistant to antibiotics due to multiple chromosomally encoded resistant determinants. And numerous in vitro studies have demonstrated the regulatory mechanisms of antibiotic resistance related genes in response to antibiotics. However, it is not well-known how host environment affects bacterial response to antibiotics. In this study, we found that P. aeruginosa cells directly isolated from mice lungs displayed higher susceptibility to tobramycin than in vitro cultured bacteria. In vitro experiments demonstrated that incubation with A549 and differentiated HL60 (dHL60) cells sensitized P. aeruginosa to tobramycin. Further studies revealed that reactive oxygen species produced by the host cells contributed to the increased bacterial susceptibility. At the same concentration of tobramycin, presence of A549 and dHL60 cells resulted in higher expression of heat shock proteins, which are known inducible by tobramycin. Further analyses revealed decreased membrane potential upon incubation with the host cells and modification of lipopolysaccharide, which contributed to the increased susceptibility to tobramycin. Therefore, our results demonstrate that contact with host cells increased bacterial susceptibility to tobramycin. PMID:28352614

  3. Clustered Regularly Interspaced Short Palindromic Repeat-Dependent, Biofilm-Specific Death of Pseudomonas aeruginosa Mediated by Increased Expression of Phage-Related Genes.

    Science.gov (United States)

    Heussler, Gary E; Cady, Kyle C; Koeppen, Katja; Bhuju, Sabin; Stanton, Bruce A; O'Toole, George A

    2015-05-12

    The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (CRISPR/Cas) system is an adaptive immune system present in many archaea and bacteria. CRISPR/Cas systems are incredibly diverse, and there is increasing evidence of CRISPR/Cas systems playing a role in cellular functions distinct from phage immunity. Previously, our laboratory reported one such alternate function in which the type 1-F CRISPR/Cas system of the opportunistic pathogen Pseudomonas aeruginosa strain UCBPP-PA14 (abbreviated as P. aeruginosa PA14) inhibits both biofilm formation and swarming motility when the bacterium is lysogenized by the bacteriophage DMS3. In this study, we demonstrated that the presence of just the DMS3 protospacer and the protospacer-adjacent motif (PAM) on the P. aeruginosa genome is necessary and sufficient for this CRISPR-dependent loss of these group behaviors, with no requirement of additional DMS3 sequences. We also demonstrated that the interaction of the CRISPR system with the DMS3 protospacer induces expression of SOS-regulated phage-related genes, including the well-characterized pyocin operon, through the activity of the nuclease Cas3 and subsequent RecA activation. Furthermore, our data suggest that expression of the phage-related genes results in bacterial cell death on a surface due to the inability of the CRISPR-engaged strain to downregulate phage-related gene expression, while these phage-related genes have minimal impact on growth and viability under planktonic conditions. Deletion of the phage-related genes restores biofilm formation and swarming motility while still maintaining a functional CRISPR/Cas system, demonstrating that the loss of these group behaviors is an indirect effect of CRISPR self-targeting. The various CRISPR/Cas systems found in both archaea and bacteria are incredibly diverse, and advances in understanding the complex mechanisms of these varied systems has not only increased our knowledge of host

  4. The effect of sub-inhibitory concentrations of rifaximin on urease production and on other virulence factors expressed by Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus.

    Science.gov (United States)

    Ricci, Annalisa; Coppo, Erika; Barbieri, Ramona; Debbia, Eugenio A; Marchese, Anna

    2017-04-01

    Rifaximin, a topical derivative of rifampin, inhibited urease production and other virulence factors at sub-MIC concentrations in strains involved in hepatic encephalopathy and the expression of methicillin resistance in Staphylococcus aureus. In particular, urease production was affected in all Proteus mirabilis and Klebsiella pneumoniae strains as well as in all tested Pseudomonas aeruginosa isolates. Other exotoxins, synthesized by P. aeruginosa, such as protease, gelatinase, lipase, lecithinase and DNAse were also not metabolized in the presence of rifaximin. This antibiotic inhibited pigment production in both P. aeruginosa and Chromobacterium violaceum, a biosensor control strain. Lastly, rifaximin affected haemolysin production in S. aureus and was able to restore cefoxitin susceptibility when the strain was cultured in the presence of sub-MICs of the drug. The present findings confirm and extend previous observations about the beneficial effects of rifaximin for the treatment of gastrointestinal diseases, since in this anatomic site, it reaches a large array of concentrations which prevents enterobacteria from thriving and/or producing their major virulence factors.

  5. Yi Qi Qing Re Gao-containing serum inhibits lipopolysaccharide-induced rat mesangial cell proliferation by suppressing the Wnt pathway and TGF-β1 expression.

    Science.gov (United States)

    Yang, Liping; Sun, Xueyan; Zhan, Yongli; Liu, Huijie; Wen, Yumin; Mao, Huimin; Dong, X I; Li, Ping

    2016-04-01

    The aim of the present study was to investigate the effect of Yi Qi Qing Re Gao-containing serum (YQ-S) on rat mesangial cell (MC) proliferation and to investigate the underlying mechanism. MCs were divided into the control, lipopolysaccharide (LPS)-stimulated, YQ-S and fosinopril-containing serum (For-S) groups, and cultured for 48 h. An MTT assay was used to evaluate the proliferation of MCs. In addition, reverse transcription-quantitative polymerase chain reaction and western blot analysis were conducted to detect the expression levels of Wnt4, β-catenin and transforming growth factor (TGF)-β1 in MCs. The results indicated that YQ-S inhibited LPS-induced MC proliferation. The Wnt4 and TGF-β1 mRNA expression levels were reduced in the YQ-S group (P<0.01 or P<0.05). Furthermore, the Wnt4, β-catenin and TGF-β1 protein expression levels were suppressed in the YQ-S group (P<0.01 or P<0.05). Therefore, YQ-S appears to inhibit MC proliferation, and its mechanism may involve the inhibition of the Wnt signaling pathway and downregulation of TGF-β1 expression.

  6. The Effect of Agmatine on Expression of IL-1β and TLX Which Promotes Neuronal Differentiation in Lipopolysaccharide-Treated Neural Progenitors.

    Science.gov (United States)

    Song, Juhyun; Kumar, Bokara Kiran; Kang, Somang; Park, Kyung Ah; Lee, Won Taek; Lee, Jong Eun

    2013-12-01

    Differentiation of neural progenitor cells (NPCs) is important for protecting neural cells and brain tissue during inflammation. Interleukin-1 beta (IL-1β) is the most common pro- inflammatory cytokine in brain inflammation, and increased IL-1β levels can decrease the proliferation of NPCs. We aimed to investigate whether agmatine (Agm), a primary polyamine that protects neural cells, could trigger differentiation of NPCs by activating IL-1β in vitro. The cortex of ICR mouse embryos (E14) was dissociated to culture NPCs. NPCs were stimulated by lipopolysaccharide (LPS). After 6 days, protein expression of stem cell markers and differentiation signal factors was confirmed by using western blot analysis. Also, immunocytochemistry was used to confirm the cell fate. Agm treatment activated NPC differentiation significantly more than in the control group, which was evident by the increased expression of a neuronal marker, MAP2, in the LPS-induced, Agm-treated group. Differentiation of LPS-induced, Agm-treated NPCs was regulated by the MAPK pathway and is thought to be related to IL-1β activation and decreased expression of TLX, a transcription factor that regulates NPC differentiation. Our results reveal that Agm can promote NPC differentiation to neural stem cells by modulating IL-1β expression under inflammatory condition, and they suggest that Agm may be a novel therapeutic strategy for neuroinflammatory diseases.

  7. Arctigenin inhibits lipopolysaccharide-induced iNOS expression in RAW264.7 cells through suppressing JAK-STAT signal pathway.

    Science.gov (United States)

    Kou, Xianjuan; Qi, Shimei; Dai, Wuxing; Luo, Lan; Yin, Zhimin

    2011-08-01

    Arctigenin has been demonstrated to have an anti-inflammatory function, but the precise mechanisms of its action remain to be fully defined. In the present study, we determined the effects of arctigenin on lipopolysaccharide (LPS)-induced production of proinflammatory mediators and the underlying mechanisms involved in RAW264.7 cells. Our results indicated that arctigenin exerted its anti-inflammatory effect by inhibiting ROS-dependent STAT signaling through its antioxidant activity. Arctigenin also significantly reduced the phosphorylation of STAT1 and STAT 3 as well as JAK2 in LPS-stimulated RAW264.7 cells. The inhibitions of STAT1 and STAT 3 by arctigenin prevented their translocation to the nucleus and consequently inhibited expression of iNOS, thereby suppressing the expression of inflammation-associated genes, such as IL-1β, IL-6 and MCP-1, whose promoters contain STAT-binding elements. However, COX-2 expression was slightly inhibited at higher drug concentrations (50 μM). Our data demonstrate that arctigenin inhibits iNOS expression via suppressing JAK-STAT signaling pathway in macrophages. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  8. Neonatal manipulation of oxytocin prevents lipopolysaccharide-induced decrease in gene expression of growth factors in two developmental stages of the female rat.

    Science.gov (United States)

    Bakos, Jan; Lestanova, Zuzana; Strbak, Vladimir; Havranek, Tomas; Bacova, Zuzana

    2014-10-01

    Oxytocin production and secretion is important for early development of the brain. Long-term consequences of manipulation of oxytocin system might include changes in markers of brain plasticity - cytoskeletal proteins and neurotrophins. The aim of the present study was (1) to determine whether neonatal oxytocin administration affects gene expression of nestin, microtubule-associated protein-2 (MAP-2), brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the brain of two developmental stages of rat and (2) to evaluate whether neonatal oxytocin administration protects against lipopolysaccharide (LPS) induced inflammation. Neonatal oxytocin did not prevent a decrease of body weight in the LPS treated animals. Oxytocin significantly increased gene expression of BDNF in the right hippocampus in 21-day and 2-month old rats of both sexes. Gene expression of NGF and MAP-2 significantly increased in males treated with oxytocin. Both, growth factors and intermediate filament-nestin mRNA levels, were reduced in females exposed to LPS. Oxytocin treatment prevented a decrease in the gene expression of only growth factors. In conclusion, neonatal manipulation of oxytocin has developmental and sex-dependent effect on markers of brain plasticity. These results also indicate, that oxytocin may be protective against inflammation particularly in females. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Single-Cell Mass Spectrometry Reveals Changes in Lipid and Metabolite Expression in RAW 264.7 Cells upon Lipopolysaccharide Stimulation

    Science.gov (United States)

    Yang, Bo; Patterson, Nathan Heath; Tsui, Tina; Caprioli, Richard M.; Norris, Jeremy L.

    2018-05-01

    It has been widely recognized that individual cells that exist within a large population of cells, even if they are genetically identical, can have divergent molecular makeups resulting from a variety of factors, including local environmental factors and stochastic processes within each cell. Presently, numerous approaches have been described that permit the resolution of these single-cell expression differences for RNA and protein; however, relatively few techniques exist for the study of lipids and metabolites in this manner. This study presents a methodology for the analysis of metabolite and lipid expression at the level of a single cell through the use of imaging mass spectrometry on a high-performance Fourier transform ion cyclotron resonance mass spectrometer. This report provides a detailed description of the overall experimental approach, including sample preparation as well as the data acquisition and analysis strategy for single cells. Applying this approach to the study of cultured RAW264.7 cells, we demonstrate that this method can be used to study the variation in molecular expression with cell populations and is sensitive to alterations in that expression that occurs upon lipopolysaccharide stimulation. [Figure not available: see fulltext.

  10. [Effects of lipopolysaccharides extracted from Porphyromonas endodontalis on the expression of IL-1beta mRNA and IL-6 mRNA in osteoblasts].

    Science.gov (United States)

    Yang, Di; Li, Ren; Qiu, Li-Hong; Li, Chen

    2009-04-01

    To quantify the IL-1 beta mRNA and IL-6 mRNA expression induced by lipopolysaccharides (LPS)extracted from Porphyromonas endodontalis(P.e) in osteoblasts, and to relate P.e-LPS to bone absorption pathogenesis in lesions of chronical apical periodontitis. MG63 was treated with different concentrations of P.e-LPS(0-50 microg/mL) for different hours(0-24h). The expression of IL-1 beta mRNA and IL-6 mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR).Statistical analysis was performed using one- way ANOVA and Dunnett t test with SPSS11.0 software package. The level of IL-1 beta mRNA and IL-6 mRNA increased significantly after treatment with P.e-LPS at more than 5 microg/mL (P<0.01)and for more than 1 hour (P<0.01), which indicated that P.e-LPS induced osteoblasts to express IL-1 beta mRNA and IL-6 mRNA in dose and time dependent manners. P.e-LPS may promote bone resorption in lesions of chronical apical periodontitis by inducing IL-1 beta mRNA and IL-6 mRNA expression in osteoblasts.

  11. Single-Cell Mass Spectrometry Reveals Changes in Lipid and Metabolite Expression in RAW 264.7 Cells upon Lipopolysaccharide Stimulation

    Science.gov (United States)

    Yang, Bo; Patterson, Nathan Heath; Tsui, Tina; Caprioli, Richard M.; Norris, Jeremy L.

    2018-03-01

    It has been widely recognized that individual cells that exist within a large population of cells, even if they are genetically identical, can have divergent molecular makeups resulting from a variety of factors, including local environmental factors and stochastic processes within each cell. Presently, numerous approaches have been described that permit the resolution of these single-cell expression differences for RNA and protein; however, relatively few techniques exist for the study of lipids and metabolites in this manner. This study presents a methodology for the analysis of metabolite and lipid expression at the level of a single cell through the use of imaging mass spectrometry on a high-performance Fourier transform ion cyclotron resonance mass spectrometer. This report provides a detailed description of the overall experimental approach, including sample preparation as well as the data acquisition and analysis strategy for single cells. Applying this approach to the study of cultured RAW264.7 cells, we demonstrate that this method can be used to study the variation in molecular expression with cell populations and is sensitive to alterations in that expression that occurs upon lipopolysaccharide stimulation. [Figure not available: see fulltext.

  12. Sirtuin 1 regulates matrix metalloproteinase-13 expression induced by Porphyromonas endodontalis lipopolysaccharide via targeting nuclear factor–κB in osteoblasts

    Science.gov (United States)

    Qu, Liu; Yu, Yaqiong; Qiu, Lihong; Yang, Di; Yan, Lu; Guo, Jiajie; Jahan, Rabita

    2017-01-01

    ABSTRACT Porphyromonas endodontalis lipopolysaccharide (P.e LPS) is an important initiating factor for periapical inflammation and bone destruction. Matrix metalloproteinase-13 (MMP-13) has been shown to participate in the formation and diffusion of periapical bone lesion in chronic apical periodontitis. Sirtuin 1 (SIRT1) is a key regulator of inflammation in mammalian cells which suppresses the release of inflammatory mediators. This study aimed to explore the role of SIRT1 in regulating MMP-13 expression induced by P.e LPS in osteoblasts. P.e LPS stimulated MMP-13 expression in MC3T3-E1 cells. Knockdown of SIRT1 reinforced the increase of MMP-13mRNA expression induced by P.e LPS. SIRT1 activator resveratrol significantly reduced the expression of MMP-13 and SIRT1 inhibitor EX-527 enhanced the expression of MMP-13. Moreover, SIRT1 activation with resveratrol inhibited acetylation of NF-κB p65 and NF-κB transcriptional activity, which were enhanced by P.e LPS. In addition, NF-κB p65 was involved in P.e LPS-induced MMP-13 expression via directly binding to the MMP-13 promoter. However, SIRT1 activation significantly interfered with this binding. These findings strongly suggest that P.e LPS induces MMP-13 expression in osteoblasts, and SIRT1 suppresses this expression of MMP-13 through targeting NF-κB p65. This provides new insights into understanding the actions of SIRT1 on anti-inflammatory and anti-bone resorption activity. PMID:28473882

  13. Sirtuin 1 regulates matrix metalloproteinase-13 expression induced by Porphyromonas endodontalis lipopolysaccharide via targeting nuclear factor-κB in osteoblasts.

    Science.gov (United States)

    Qu, Liu; Yu, Yaqiong; Qiu, Lihong; Yang, Di; Yan, Lu; Guo, Jiajie; Jahan, Rabita

    2017-01-01

    Porphyromonas endodontalis lipopolysaccharide (P.e LPS) is an important initiating factor for periapical inflammation and bone destruction. Matrix metalloproteinase-13 (MMP-13) has been shown to participate in the formation and diffusion of periapical bone lesion in chronic apical periodontitis. Sirtuin 1 (SIRT1) is a key regulator of inflammation in mammalian cells which suppresses the release of inflammatory mediators. This study aimed to explore the role of SIRT1 in regulating MMP-13 expression induced by P.e LPS in osteoblasts. P.e LPS stimulated MMP-13 expression in MC3T3-E1 cells. Knockdown of SIRT1 reinforced the increase of MMP-13mRNA expression induced by P.e LPS. SIRT1 activator resveratrol significantly reduced the expression of MMP-13 and SIRT1 inhibitor EX-527 enhanced the expression of MMP-13. Moreover, SIRT1 activation with resveratrol inhibited acetylation of NF-κB p65 and NF-κB transcriptional activity, which were enhanced by P.e LPS. In addition, NF-κB p65 was involved in P.e LPS-induced MMP-13 expression via directly binding to the MMP-13 promoter. However, SIRT1 activation significantly interfered with this binding. These findings strongly suggest that P.e LPS induces MMP-13 expression in osteoblasts, and SIRT1 suppresses this expression of MMP-13 through targeting NF-κB p65. This provides new insights into understanding the actions of SIRT1 on anti-inflammatory and anti-bone resorption activity.

  14. Ganoderma lucidum Polysaccharides Reduce Lipopolysaccharide-Induced Interleukin-1β Expression in Cultured Smooth Muscle Cells and in Thoracic Aortas in Mice

    Directory of Open Access Journals (Sweden)

    Chan-Jung Liang

    2014-01-01

    Full Text Available The expression of inflammatory cytokines on vascular walls is a critical event in vascular diseases and inflammation. The aim of the present study was to examine the effects of an extract of Ganoderma lucidum (Reishi polysaccharides (EORPs, which is effective against immunological disorders, on interleukin- (IL- 1β expression by human aortic smooth muscle cells (HASMCs and the underlying mechanism. The lipopolysaccharide- (LPS- induced IL-1β expression was significantly reduced when HASMCs were pretreated with EORP by Western blot and immunofluorescent staining. Pretreatment with 10 μg/mL EORP decreased LPS-induced ERK, p38, JNK, and Akt phosphorylation. But the increase in IL-1β expression with LPS treatment was only inhibited by pretreatment with the ERK1/2 inhibitor, while the JNK and p38 inhibitors had no effect. In addition, EORP reduced the phosphorylation and nuclear translocation of nuclear factor- (NF- κB p65 in LPS-treated HASMCs. Furthermore, in vivo, IL-1β expression was strongly expressed in thoracic aortas in LPS-treated mice. Oral administration of EORP decreased IL-1β expression. The level of IL-1β expression in LPS-treated or in LPS/EORP-treated group was very low and was similar to that of the saline-treated group in toll-like receptor 4-deficient (TLR4−/− mice. These findings suggest that EORP has the anti-inflammatory property and could prove useful in the prevention of vascular diseases and inflammatory responses.

  15. Lipopolysaccharide (LPS) stimulates adipokine and socs3 gene expression in mouse brain and pituitary gland in vivo, and in N-1 hypothalamic neurons in vitro.

    Science.gov (United States)

    Brown, Russell; Imran, Syed A; Wilkinson, Michael

    2009-04-30

    Adipokines that modulate metabolic and inflammatory responses, such as resistin (rstn) and fasting-induced adipose factor (fiaf), are also expressed in mouse brain and pituitary gland. Since lipopolysaccharide (LPS)-induced endotoxinemia provokes an anorectic response via a hypothalamic-dependent mechanism we hypothesized that LPS would also modify hypothalamic adipokine expression. Challenging male CD-1 mice with LPS (5 mg/kg; s.c.) significantly reduced bodyweight (24 h) and realtime RT-PCR revealed time- and tissue-dependent increases in rstn, fiaf and suppressor of cytokine signaling-3 (socs-3) mRNA in hypothalamic, pituitary, cortical and adipose tissues. Gene expression was rapidly increased (3-6 h) in the hypothalamus and pituitary, but returned to normal within 24 h. In contrast, with the exception of rstn in fat, the expression of target genes remained elevated in cortex and visceral fat at 24 h post-injection. In order to more specifically examine the hypothalamic response to LPS we investigated its effects directly on N-1 hypothalamic neurons in vitro. LPS (25 microg/mL; 3 h) had no effect on rstn mRNA, but significantly stimulated fiaf and socs-3 expression. Although various toll-like receptor 4 (TLR4) antagonists (parthenolide, PD098059, and SB202190) did not prevent the LPS-induced increases in fiaf and socs-3, they did partially attenuate its stimulatory effects. We conclude that LPS treatment increases the expression of central, and possibly neuronal, adipokine genes which may influence local tissue repair and function, but could also have downstream consequences on the hypothalamic control of appetite and energy metabolism following an inflammatory insult.

  16. TRIB3 mediates the expression of Wnt5a and activation of nuclear factor-κB in Porphyromonas endodontalis lipopolysaccharide-treated osteoblasts.

    Science.gov (United States)

    Yu, Y; Qiu, L; Guo, J; Yang, D; Qu, L; Yu, J; Zhan, F; Xue, M; Zhong, M

    2015-08-01

    Porphyromonas endodontalis lipopolysaccharide (LPS) is considered to be correlated with the progression of bone resorption in periodontal and periapical diseases. Wnt5a has recently been implicated in inflammatory processes, but its role is unclear as a P. endodontalis LPS-induced mediator in osteoblasts. Tribbles homolog 3 (TRIB3) encodes a pseudokinase and has been linked to inflammation in certain situations. Here, we found that P. endodontalis LPS induced Wnt5a expression in a dose- and time-dependent manner and it also upregulated translocation, phosphorylation and transcriptional activity of nuclear factor-κB (NF-κB) in MC3T3-E1 cells. Bay 11-7082 blocked the translocation of NF-κB and Wnt5a expression induced by P. endodontalis LPS. Chromatin immunoprecipitation assay further established that induction of Wnt5a by P. endodontalis LPS was mediated through the NF-κB p65 subunit. Additionally, P. endodontalis LPS increased expression of TRIB3 in osteoblasts after 10 h simulated time. Overexpression of TRIB3 enhanced NF-κB phosphorylation and Wnt5a induction, whereas knockdown of TRIB3 inhibited NF-κB phosphorylation and Wnt5a expression in P. endodontalis LPS-stimulated osteoblasts. These results suggest that P. endodontalis LPS has the ability to promote the expression of Wnt5a in mouse osteoblasts, and this induction is mainly mediated by NF-κB pathway. TRIB3 seems to modulate the sustained expression of Wnt5a in osteoblasts stimulated by P. endodontalis LPS, as well as regulating NF-κB phosphorylation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.

    OpenAIRE

    Burns, F R; Paterson, C A; Gray, R D; Wells, J T

    1990-01-01

    Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL...

  18. Divergence of canonical danger signals: The genome-level expression patterns of human mononuclear cells subjected to heat shock or lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Sakthivel Bhuvaneswari

    2008-05-01

    Full Text Available Abstract Background Peripheral blood mononuclear cells (PBMC serve a sentinel role allowing the host to efficiently sense and adapt to the presence of danger signals. Herein we have directly compared the genome-level expression patterns (microarray of a human PBMC model (THP-1 cells subjected to one of two canonical danger signals, heat shock or lipopolysaccharide (LPS. Results and Discussion Based on sequential expression and statistical filters, and in comparison to control cells, we found that 3,988 genes were differentially regulated in THP-1 cells subjected to LPS stress, and 2,921 genes were differentially regulated in THP-1 cells subjected to heat shock stress. Venn analyses demonstrated that the majority of differentially regulated genes (≥ 70% were uniquely expressed in response to one of the two danger signals. Functional analyses demonstrated that the two danger signals induced expression or repression of genes corresponding to unique pathways, molecular functions, biological processes, and gene networks. In contrast, there were 184 genes that were commonly upregulated by both stress signals, and 430 genes that were commonly downregulated by both stress signals. Interestingly, the 184 commonly upregulated genes corresponded to a gene network broadly related to inflammation, and more specifically to chemokine signaling. Conclusion These data demonstrate that the mononuclear cell responses to the canonical stress signals, heat shock and LPS, are highly divergent. However, there is a heretofore unrecognized common pattern of gene network expression corresponding to chemokine-related biology. The data also serve as a reference database for investigators in the field of stress signaling.

  19. Extract of corn silk (stigma of Zea mays) inhibits the tumour necrosis factor-alpha- and bacterial lipopolysaccharide-induced cell adhesion and ICAM-1 expression.

    Science.gov (United States)

    Habtemariam, S

    1998-05-01

    Treatment of human endothelial cells with cytokines such as tumour necrosis factor-alpha (TNF) or E. coli lipopolysaccharide (LPS) induces the expression of several adhesion molecules and enhances leukocyte adhesion to endothelial cell surface. Interfering with this leukocyte adhesion or adhesion molecules upregulation is an important therapeutic target for the treatment of bacterial sepsis and various inflammatory diseases. In the course of screening marketed European anti-inflammatory herbal drugs for TNF antagonistic activity, a crude ethanolic extract of corn silk (stigma of Zea mays) exhibited significant activity. The extract at concentrations of 9-250 micrograms/ml effectively inhibited the TNF- and LPS-induced adhesiveness of EAhy 926 endothelial cells to monocytic U937 cells. Similar concentration ranges of corn silk extract did also block the TNF and LPS but not the phorbol 12-myristate 13-acetate-induced ICAM-1 expression on EAhy 926 endothelial cell surface. The extract did not alter the production of TNF by LPS-activated macrophages and failed to inhibit the cytotoxic activity of TNF. It is concluded that corn silk possesses important therapeutic potential for TNF- and LPS-mediated leukocyte adhesion and trafficking.

  20. Preparation of procyanidin B2 from apple pomace and its inhibitory effect on the expression of cyclooxygenase-2 in lipopolysaccharide-treated RAW264.7 macrophages

    Directory of Open Access Journals (Sweden)

    Huawei Zhang

    2011-06-01

    Full Text Available Dimeric procyanidin B2 (PB2 is one of phenolic compounds in apple pomace, an agro-industrial byproduct in apple juice processing. This work focused on purification of PB2 from apple pomace using sephadex column chromatography and its potential effect on lipopolysaccharide (LPS-induced inflammation using RAW264.7 macrophages. PB2 with the purity of 72.28 ± 1.85% was successfully afforded using resin and gel column chromatographic technique. Anti-inflammatory tests suggested that the expression of cyclooxygenase-2 (COX-2 in LPS-induced murine RAW264.7 macrophages was suppressed in a PB2 concentration-dependent manner. PB2 at no less than 50 μg·mL-1 could significantly suppress inflammation in the LPS-induced cells. Moreover, this suppressive effect was not correlated with PB2 pretreating. However, the COX-2 expression was not reduced in LPS pretreatment way followed by PB2 exposure, which suggested that PB2 has no repairing function. The results showed that high pure PB2 prepared from apple pomace has a remarkable anti-inflammatory property.

  1. Endogenous expression pattern of resolvin D1 in a rat model of self-resolution of lipopolysaccharide-induced acute respiratory distress syndrome and inflammation.

    Science.gov (United States)

    Sun, Wei; Wang, Zai-ping; Gui, Ping; Xia, Weiyi; Xia, Zhengyuan; Zhang, Xing-cai; Deng, Qing-zhu; Xuan, Wei; Marie, Christelle; Wang, Lin-lin; Wu, Qing-ping; Wang, Tingting; Lin, Yun

    2014-11-01

    Resolvin D1 (RvD1), an endogenous lipid mediator derived from docosahexaenoic acid, has been reported to promote a biphasic activity in anti-inflammatory response and regulate inflammatory resolution. The present study aimed to determine the endogenous expression pattern of RvD1 in a rat model of self-resolution of lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) and inflammation. The ARDS model was induced by administrating LPS (2mg/kg) via tracheotomy in 138 male Sprague-Dawley rats. At specified time points, lung injury and inflammation were respectively assessed by lung histology and analysis of bronchoalveolar lavage fluid and cytokine levels. The expression of endogenous RvD1 was detected by high performance liquid chromatography and tandem mass spectrometry. The results showed that histological lung injury peaked between 6h (LPS6h) and day 3, followed by recovery over 4-10 days after LPS administration. Lung tissue polymorph nuclear cell (PMN) was significantly increased at LPS6h, and peaked between 6h to day 2. The levels of interleukin (IL)-6 and IL-10 were significantly increased at LPS6h and remained higher over day 10 as compared to baseline. Intriguingly, the endogenous RvD1 expression was decreased gradually during the first 3 days, followed by almost completely recovery over days 9-10. The finding indicated that endogenous RvD1 underwent a decrease in expression followed by gradual increase that was basically coincident with the lung injury recovery in a rat model of self-resolution LPS-induced ARDS and inflammation. Our results may help define the optimal therapeutic window for endogenous RvD1 to prevent or treat LPS-induced ARDS and inflammation. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. [Effect of NF-κB on the expression of interleukin-6 induced by lipopolysaccharides of Porphyromonas endodontalis in MC3T3-E1 cells].

    Science.gov (United States)

    Yu, Ya-qiong; Guo, Jia-jie; Qiu, Li-hong; Lv, You; Jia, Ge; Guo, Yan

    2013-08-01

    To investigate the effect of NF-κB signaling on the expression of interleukin-6(IL-6) induced by lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) in MC3T3-El cells. MC3T3-E1 cells were pretreated with BAY-117082 for 1 h, and then were treated with 10 mg/L P.e-LPS for different times. The translocation of NF-κB was observed by immunofluorescence. The expression of IL-6 was detected by reverse transcription polymerse chain reaction (RT-PCR) and enzyme-linked immuno sorbent assay (ELISA). Statistical analysis was performed using multi-way ANOVA and Dunnett's t test with SPSS 13.0 software package. The staining of NF-κB was mostly in cytoplasm in untreated cells. Rapid translocation of NF-κB into nucleus was observed in the cells stimulated for 30 min and mostly relocalization of NF-κB from nucleus to cytoplasm was observed after 60 min. Pretreatment with 10 μmol/L BAY-117082 for 1h significantly inhibited P.e-LPS-induced translocation of NF-κB .The mRNA and proteins of IL-6 decreased significantly after pretreatment with 10 μmol/L BAY-117082 and the expression of IL-6 proteins was reduced from (774.983±6.585) ng/L to (377.384±14.620) ng/L (P<0.01). The group of treatment with BAY-117082 alone had no significant difference from the blank control group. P.e-LPS can induce translocation of NF-κB in mouse osteoblast MC3T3-El, and P.e-LPS may induce the expression of IL-6 in mouse osteoblast through the signaling of NF-κB.

  3. DNA methylcytosine dioxygenase ten-eleven translocation 2 enhances lipopolysaccharide-induced cytokine expression in human dental pulp cells by regulating MyD88 hydroxymethylation.

    Science.gov (United States)

    Wang, Xinxuan; Feng, Zhihui; Li, Qimeng; Yi, Baicheng; Xu, Qiong

    2018-04-13

    Dental pulp inflammation is a bacterially driven inflammation process characterized by the local accumulation of cytokines/chemokines that participate in destructive processes in the pulp. Multiple mechanisms are involved in dental pulp inflammation, including epigenetic events, such as DNA methylation/demethylation. Ten-eleven translocation 2 (TET2) is a recently discovered DNA methylcytosine dioxygenase that plays important roles in inflammatory disease. However, its role in the inflammatory response of dental pulp is unknown. We observed elevated mRNA and protein levels of TET2 after lipopolysaccharide (LPS) stimulation in human dental pulp cells (hDPCs). To identify the effects of TET2 on cytokine expression, TET2 was knocked down and cytokines were detected using a cytokine antibody array after LPS stimulation. The protein expression of GM-CSF, IL-6, IL-8 and RANTES decreased in the LPS-induced hDPCs following TET2 knockdown. The downregulated expression levels of IL-6 and IL-8 were further confirmed by real-time quantitative polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Additionally, the phosphorylation levels of IKK-α/β, p65 and IκBα of the NF-κB signaling pathway were decreased in the TET2-silenced group. Furthermore, the global 5-hydroxymethylcytosine (5hmC) level was significantly decreased and the genomic 5-methylcytosine (5mC) level was increased in the TET2-deficient hDPCs; TET2 depletion resulted in a decrease in the 5hmC level of the MyD88 promoter following LPS stimulation. These findings indicate that TET2 knockdown inhibits LPS-induced inflammatory response in hDPCs by downregulating MyD88 hydroxymethylation. Thus, TET2-dependent DNA demethylation might play an important role in dental pulp inflammation as an epigenetic regulator.

  4. Analysis of the kinetic of expression of tristetraprolin and HuR by rheumatoid arthritis patients pheripheral blood mononuclear cells stimulated with lipopolysaccharide

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    G. Ferraccioli

    2011-09-01

    Full Text Available Objective. Given the role of TNF-α in Rheumatoid Arthritis (RA we decided to define the characteristics of the TNF- α synthesis by peripheral blood mononuclear cells (PBMNCs obtained from active-aggressive RA patients giving a particular attention to the modulation of the expression of two fundamental proteins in TNF-α mRNA stability regulation, Tristetraprolin (TTP and HuR. Methods. 11 RA patients with active disease were enrolled in the study before their entry in 2 double blind protocols: Infliximab versus MTX and Etanercept versus MTX. 9 healthy blood donors were taken as controls. PBMNCs obtained by Ficoll centrifugation and plastic adherence were stimulated with lipopolysaccharide (LPS and TNF-α was measured in the supernatant during 8 hours by ELISA. At each time point the cells were harvested and analysed for TNF- α, TTP and HuR mRNA expression by semi-quantitative PCR. Results. MNCs TNF-α secretion after LPS stimulation did not differ significantly between RA and control subjects, even if a tendency towards a more prompt response was observed in the patients. More importantly only the DMARDs responsive patients (DAS <3.7 at the 6th month, with a minimal reduction of 1.2 points disclosed precociously (at the first month a significant change in the profile of TNF-α secretion and maintained it until the 6th month. The “normalization” of the synthetic behaviour was accompanied by the resetting in the regulation of the expression of the TTP, that appeared significantly different in the patients before and after therapy. Conclusions. Independently from the type of therapy, responsive patients demonstrate a rapid change in the cellular biology at the systemic level that might drive the resolution of the phlogistic process at the synovial level.

  5. Lipopolysaccharide-Elicited TSLPR Expression Enriches a Functionally Discrete Subset of Human CD14+ CD1c+ Monocytes.

    Science.gov (United States)

    Borriello, Francesco; Iannone, Raffaella; Di Somma, Sarah; Vastolo, Viviana; Petrosino, Giuseppe; Visconte, Feliciano; Raia, Maddalena; Scalia, Giulia; Loffredo, Stefania; Varricchi, Gilda; Galdiero, Maria Rosaria; Granata, Francescopaolo; Del Vecchio, Luigi; Portella, Giuseppe; Marone, Gianni

    2017-05-01

    Thymic stromal lymphopoietin (TSLP) is a cytokine produced mainly by epithelial cells in response to inflammatory or microbial stimuli and binds to the TSLP receptor (TSLPR) complex, a heterodimer composed of TSLPR and IL-7 receptor α (CD127). TSLP activates multiple immune cell subsets expressing the TSLPR complex and plays a role in several models of disease. Although human monocytes express TSLPR and CD127 mRNAs in response to the TLR4 agonist LPS, their responsiveness to TSLP is poorly defined. We demonstrate that TSLP enhances human CD14 + monocyte CCL17 production in response to LPS and IL-4. Surprisingly, only a subset of CD14 + CD16 - monocytes, TSLPR + monocytes (TSLPR + mono), expresses TSLPR complex upon LPS stimulation in an NF-κB- and p38-dependent manner. Phenotypic, functional, and transcriptomic analysis revealed specific features of TSLPR + mono, including higher CCL17 and IL-10 production and increased expression of genes with important immune functions (i.e., GAS6 , ALOX15B , FCGR2B , LAIR1 ). Strikingly, TSLPR + mono express higher levels of the dendritic cell marker CD1c. This evidence led us to identify a subset of peripheral blood CD14 + CD1c + cells that expresses the highest levels of TSLPR upon LPS stimulation. The translational relevance of these findings is highlighted by the higher expression of TSLPR and CD127 mRNAs in monocytes isolated from patients with Gram-negative sepsis compared with healthy control subjects. Our results emphasize a phenotypic and functional heterogeneity in an apparently homogeneous population of human CD14 + CD16 - monocytes and prompt further ontogenetic and functional analysis of CD14 + CD1c + and LPS-activated CD14 + CD1c + TSLPR + mono. Copyright © 2017 by The American Association of Immunologists, Inc.

  6. Colony to colorimetry in 6 h: ELISA detection of a surface-expressed Pseudomonas aeruginosa virulence factor using immobilized bacteria.

    Science.gov (United States)

    Adawi, Azmi; Neville, Lewis F

    2012-09-01

    A rapid ELISA employing intact Pseudomonas aeruginosa (PA) is described that allows discrimination between strains harboring flagellin type a or b. All 52 PA strains known to harbor flagellin type b were positive in this ELISA when screened with a fully human monoclonal antibody (LST-007) targeting flagellin type b. Completion of this assay in only 6 h, from picking a single bacterial colony to a colorimetric product, could easily be adapted to a clinical laboratory setting and permit the appropriate choice of therapeutic monoclonal antibody versus its homologous flagellin target in PA-infected patients. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Dynamic expression of leukocyte innate immune genes in whole blood from horses with lipopolysaccharide-induced acute systemic inflammation

    DEFF Research Database (Denmark)

    Vinther, Anne Mette L.; Skovgaard, Kerstin; Heegaard, Peter M. H.

    2015-01-01

    Background: In horses, insights into the innate immune processes in acute systemic inflammation are limited even though these processes may be highly important for future diagnostic and therapeutic advances in high-mortality disease conditions as the systemic inflammatory response syndrome (SIRS......) and sepsis. Therefore, the aim of this study was to investigate the expression of 31 selected blood leukocyte immune genes in an equine model of acute systemic inflammation to identify significantly regulated genes and to describe their expression dynamics during a 24-h experimental period. Systemic...... expressions in blood leukocytes during equine acute LPS-induced systemic inflammation thoroughly characterized a highly regulated and dynamic innate immune response. These results provide new insights into the molecular mechanisms of equine systemic inflammation....

  8. Heterologous co-expression of accA, fabD, and thioesterase genes for improving long-chain fatty acid production in Pseudomonas aeruginosa and Escherichia coli.

    Science.gov (United States)

    Lee, Sunhee; Jeon, Eunyoung; Jung, Yeontae; Lee, Jinwon

    2012-05-01

    The goal of the present study was to increase the content of intracellular long-chain fatty acids in two bacterial strains, Pseudomonas aeruginosa PA14 and Escherichia coli K-12 MG1655, by co-overexpressing essential enzymes that are involved in the fatty acid synthesis metabolic pathway. Recently, microbial fatty acids and their derivatives have been receiving increasing attention as an alternative source of fuel. By introducing two genes (accA and fabD) of P. aeruginosa into the two bacterial strains and by co-expressing with them the fatty acyl-acyl carrier protein thioesterase gene of Streptococcus pyogenes (strain MGAS10270), we have engineered recombinant strains that are efficient producers of long-chain fatty acids (C16 and C18). The recombinant strains exhibit a 1.3-1.7-fold increase in the production of long-chain fatty acids over the wild-type strains. To enhance the production of total long-chain fatty acids, we researched the carbon sources for optimized culture conditions and results were used for post-culture incubation period. E. coli SGJS17 (containing the accA, fabD, and thioesterase genes) produced the highest content of intracellular total fatty acids; in particular, the unsaturated fatty acid content was about 20-fold higher than that in the wild-type E. coli.

  9. Molecular and functional analyses of novel anti-lipopolysaccharide factors in giant river prawn (Macrobrachium rosenbergii, De Man) and their expression responses under pathogen and temperature exposure.

    Science.gov (United States)

    Srisapoome, Prapansak; Klongklaew, Nawanith; Areechon, Nontawith; Wongpanya, Ratree

    2018-06-15

    Anti-lipopolysaccharide factor (ALF) is an immune-related protein that is crucially involved in immune defense mechanisms against invading pathogens in crustaceans. In the current study, three different ALFs of giant river prawn (Mr-ALF3, Mr-ALF8 and Mr-ALF9) were discovered. Based on sequence analysis, Mr-ALF3 and Mr-ALF9 were identified as new members of ALFs in crustaceans (groups F and G, respectively). Structurally, each newly identified Mr-ALF contained three α-helices packed against a four-stranded β-sheet bearing the LPS-binding motif, which usually binds to the cell wall components of bacteria. Tissue expression analysis using quantitative real-time RT-PCR (qRT-PCR) demonstrated that Mr-ALF3 was expressed in most tissues, and the highest expression was in the heart and hemocytes. The Mr-ALF8 gene was highly expressed in the heart, hemocytes, midgut, hepatopacreas and hindgut, respectively, while the Mr-ALF9 gene was modestly expressed in the heart and hemocytes, respectively. The transcriptional responses of the Mr-ALFs to Aeromonas hydrophila and hot/cold temperatures were investigated by qRT-PCR in the gills, hepatopancreas and hemocytes. We found that all Mr-ALFs were clearly suppressed in all tested tissues when the experimental prawns were exposed to extreme temperatures (25 and 35 °C). Moreover, the expression levels of these genes were significantly induced in all examined tissues by 2 different concentrations of A. hydrophila (1 × 10 6 and 1 × 10 9  CFU/ml), particularly 12 and 96 h after the injection. Finally, binding activity analysis of LPS-motif peptides of each Mr-ALF revealed that the LPS peptide of Mr-ALF3 exhibited the strongest adhesion to two pathogenic Gram-negative bacteria, A. hydrophila and Vibrio harveyi, and the non-pathogenic Gram-positive Bacillus megaterium. The results also showed that the Mr-ALF8 and Mr-ALF9 peptides had mild antimicrobial effects against similar tested bacteria. Based on information

  10. Effects of cortisol and lipopolysaccharide on expression of select growth-, stress- and immune-related genes in rainbow trout liver

    Science.gov (United States)

    Many studies have shown that stress-induced cortisol levels negatively influence growth and immunity in finfish. Despite this knowledge, few studies have assessed the direct effects of cortisol on liver immune function in finfish. Using real-time PCR, the expression of three cortisol-responsive ge...

  11. Expression, purification and preliminary crystallographic analysis of the T6SS effector protein Tse3 from Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Lu, Defen; Shang, Guijun; Yu, Qian; Zhang, Heqiao; Zhao, Yanyu; Cang, Huaixing; Gu, Lichuan; Xu, Sujuan; Huang, Yan

    2013-01-01

    Tse3, one of the effectors of the type VI secretion system in Pseudomonas aeruginosa, has been crystallized and diffracted to 1.5 Å resolution. Pseudomonas aeruginosa uses the type VI secretion system (T6SS) to inject effector proteins into rival cells in niche competition. Tse3, one of the effectors of T6SS, is delivered into the periplasm of recipient cells. Tse3 functions as a muramidase that degrades the β-1,4-linkage between N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) in peptidoglycan, thus leading to lysis of the recipient cells and providing a competitive advantage to the donor cells. Here, the preliminary crystallographic study of Tse3 is reported. A crystal of Tse3 diffracted to 1.5 Å resolution. It belonged to space group C121, with unit-cell parameters a = 166.99, b = 70.13, c = 41.94 Å, α = 90.00, β = 90.52, γ = 90.00° and one molecule per asymmetric unit

  12. Agmatine Reduces Lipopolysaccharide-Mediated Oxidant Response via Activating PI3K/Akt Pathway and Up-Regulating Nrf2 and HO-1 Expression in Macrophages.

    Directory of Open Access Journals (Sweden)

    Jianshen Chai

    Full Text Available Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on its antioxidant properties. However, the antioxidant effects of agmatine in peripheral tissues and cells, especially macrophages, remain unclear. In this study we explored the role of agmatine in mediating antioxidant effects in RAW 264.7 cells and studied its antioxidant mechanism. Our data demonstrate that agmatine is an activator of Nrf2 signaling that markedly enhances Nrf2 nuclear translocation, increases nuclear Nrf2 protein level, up-regulates the expression of the Nrf2 downstream effector HO-1, and attenuates ROS generation induced by Lipopolysaccharide (LPS. We further demonstrated that the agmatine-induced activation of Nrf2 is likely through the PI3K/Akt pathway. LY294002, a specific PI3K/Akt inhibitor, abolished agmatine-induced HO-1 up-regulation and ROS suppression significantly. Inhibiting HO-1 pathway significantly attenuated the antioxidant effect of agmatine which the products of HO-1 enzymatic activity contributed to. Furthermore, the common membrane receptors of agmatine were evaluated, revealing that α2-adrenoceptor, I1-imidazoline receptor or I2-imidazoline receptor are not required by the antioxidant properties of agmatine. Taken together, our findings revealed that agmatine has antioxidant activity against LPS-induced ROS accumulation in RAW 264.7 cells involving HO-1 expression induced by Nrf2 via PI3K/Akt pathway activation.

  13. Probiotic Bacteria Alter Pattern-Recognition Receptor Expression and Cytokine Profile in a Human Macrophage Model Challenged with Candida albicans and Lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Victor H. Matsubara

    2017-11-01

    Full Text Available Probiotics are live microorganisms that confer benefits to the host health. The infection rate of potentially pathogenic organisms such as Candida albicans, the most common agent associated with mucosal candidiasis, can be reduced by probiotics. However, the mechanisms by which the probiotics interfere with the immune system are largely unknown. We evaluated the effect of probiotic bacteria on C. albicans challenged human macrophages. Macrophages were pretreated with lactobacilli alone (Lactobacillus rhamnosus LR32, Lactobacillus casei L324m, or Lactobacillus acidophilus NCFM or associated with Escherichia coli lipopolysaccharide (LPS, followed by the challenge with C. albicans or LPS in a co-culture assay. The expression of pattern-recognition receptors genes (CLE7A, TLR2, and TLR4 was determined by RT-qPCR, and dectin-1 reduced levels were confirmed by flow cytometry. The cytokine profile was determined by ELISA using the macrophage cell supernatant. Overall probiotic lactobacilli down-regulated the transcription of CLEC7A (p < 0.05, resulting in the decreased expression of dectin-1 on probiotic pretreated macrophages. The tested Lactobacillus species down-regulated TLR4, and increased TLR2 mRNA levels in macrophages challenged with C. albicans. The cytokines profile of macrophages challenged with C. albicans or LPS were altered by the probiotics, which generally led to increased levels of IL-10 and IL-1β, and reduction of IL-12 production by macrophages (p < 0.05. Our data suggest that probiotic lactobacilli impair the recognition of PAMPs by macrophages, and alter the production of pro/anti-inflammatory cytokines, thus modulating inflammation.

  14. Involvement of JNK and NF-κB pathways in lipopolysaccharide (LPS)-induced BAG3 expression in human monocytic cells.

    Science.gov (United States)

    Wang, Hua-Qin; Meng, Xin; Liu, Bao-Qin; Li, Chao; Gao, Yan-Yan; Niu, Xiao-Fang; Li, Ning; Guan, Yifu; Du, Zhen-Xian

    2012-01-01

    Lipopolysaccharide (LPS) is an outer-membrane glycolipid component of Gram-negative bacteria known for its fervent ability to activate monocytic cells and for its potent proinflammatory capabilities. Bcl-2-associated athanogene 3 (BAG3) is a survival protein that has been shown to be stimulated during cell response to stressful conditions, such as exposure to high temperature, heavy metals, proteasome inhibition, and human immunodeficiency virus 1 (HIV-1) infection. In addition, BAG3 regulates replication of Varicella-Zoster Virus (VZV) and Herpes Simplex Virus (HSV) replication, suggesting that BAG3 could participate in the host response to infection. In the current study, we found that LPS increased the expression of BAG3 in a dose- and time-dependent manner. Actinomycin D completely blocked the LPS-induced BAG3 accumulation, as well as LPS activated the proximal promoter of BAG3 gene, supported that the induction by LPS occurred at the level of gene transcription. LPS-induced BAG3 expression was blocked by JNK or NF-κB inhibition, suggesting that JNK and NF-κB pathways participated in BAG3 induction by LPS. In addition, we also found that induction of BAG3 was implicated in monocytic cell adhesion to extracellular matrix induced by LPS. Overall, the data support that BAG3 is induced by LPS via JNK and NF-κB-dependent signals, and involved in monocytic cell-extracellular matrix interaction, suggesting that BAG3 may have a role in the host response to LPS stimulation. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Dynamic expression of leukocyte innate immune genes in whole blood from horses with lipopolysaccharide-induced acute systemic inflammation

    DEFF Research Database (Denmark)

    Vinther, Anne Mette L.; Skovgaard, Kerstin; Heegaard, Peter M. H.

    2015-01-01

    Background: In horses, insights into the innate immune processes in acute systemic inflammation are limited even though these processes may be highly important for future diagnostic and therapeutic advances in high-mortality disease conditions as the systemic inflammatory response syndrome (SIRS......) and sepsis. Therefore, the aim of this study was to investigate the expression of 31 selected blood leukocyte immune genes in an equine model of acute systemic inflammation to identify significantly regulated genes and to describe their expression dynamics during a 24-h experimental period. Systemic...... were compared with baseline levels. Results: Systemic inflammation was confirmed by the presence of clinical and hematological changes which were consistent with SIRS. The clinical response to LPS was transient and brief as all horses except one showed unaltered general demeanor after 24 h. Twenty...

  16. Inhibition of lipopolysaccharide-induced inducible nitric oxide synthase and cyclooxygenase-2 expression by xanthanolides isolated from Xanthium strumarium.

    Science.gov (United States)

    Yoon, Jeong Hoon; Lim, Hyo Jin; Lee, Hwa Jin; Kim, Hee-Doo; Jeon, Raok; Ryu, Jae-Ha

    2008-03-15

    Three sesquiterpenoids, xanthatin (1), xanthinosin (2), and 4-oxo-bedfordia acid (3) were isolated from Xanthium strumarium as inhibitors of nitric oxide synthesis in activated microglia (IC(50) values: 0.47, 11.2, 136.5 microM, respectively). Compounds 1 and 2 suppressed the expression of iNOS and COX-2 and the activity of NF-kappaB through the inhibition of LPS-induced I-kappaB-alpha degradation in microglia.

  17. The Impact of ExoS on Pseudomonas aeruginosa Internalization by Epithelial Cells Is Independent of fleQ and Correlates with Bistability of Type Three Secretion System Gene Expression.

    Science.gov (United States)

    Kroken, Abby R; Chen, Camille K; Evans, David J; Yahr, Timothy L; Fleiszig, Suzanne M J

    2018-05-01

    Pseudomonas aeruginosa is internalized into multiple types of epithelial cell in vitro and in vivo and yet is often regarded as an exclusively extracellular pathogen. Paradoxically, ExoS, a type three secretion system (T3SS) effector, has antiphagocytic activities but is required for intracellular survival of P. aeruginosa and its occupation of bleb niches in epithelial cells. Here, we addressed mechanisms for this dichotomy using invasive (ExoS-expressing) P. aeruginosa and corresponding effector-null isogenic T3SS mutants, effector-null mutants of cytotoxic P. aeruginosa with and without ExoS transformation, antibiotic exclusion assays, and imaging using a T3SS-GFP reporter. Except for effector-null PA103, all strains were internalized while encoding ExoS. Intracellular bacteria showed T3SS activation that continued in replicating daughter cells. Correcting the fleQ mutation in effector-null PA103 promoted internalization by >10-fold with or without ExoS. Conversely, mutating fleQ in PAO1 reduced internalization by >10-fold, also with or without ExoS. Effector-null PA103 remained less well internalized than PAO1 matched for fleQ status, but only with ExoS expression, suggesting additional differences between these strains. Quantifying T3SS activation using GFP fluorescence and quantitative reverse transcription-PCR (qRT-PCR) showed that T3SS expression was hyperinducible for strain PA103Δ exoUT versus other isolates and was unrelated to fleQ status. These findings support the principle that P. aeruginosa is not exclusively an extracellular pathogen, with internalization influenced by the relative proportions of T3SS-positive and T3SS-negative bacteria in the population during host cell interaction. These data also challenge current thinking about T3SS effector delivery into host cells and suggest that T3SS bistability is an important consideration in studying P. aeruginosa pathogenesis. IMPORTANCE P. aeruginosa is often referred to as an extracellular

  18. Carbon monoxide alleviates lipopolysaccharide-induced oxidative stress injury through suppressing the expression of Fis1 in NR8383 cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jia [Department of Anesthesiology, Tianjin Nankai Hospital, Tianjin Medical University, Tianjin 300100 (China); Yu, Jian-bo, E-mail: yujianbo11@126.com [Department of Anesthesiology, Tianjin Nankai Hospital, Tianjin Medical University, Tianjin 300100 (China); Liu, Wei; Wang, Dan; Zhang, Yuan; Gong, Li-rong; Dong, Shu-an [Department of Anesthesiology, Tianjin Nankai Hospital, Tianjin Medical University, Tianjin 300100 (China); Liu, Da-quan [Department of Pharmacology, Institute of Acute Abdominal Diseases of Integrated Traditional Chinese and Western Medicine, Tianjin 300100 (China)

    2016-11-15

    Acute respiratory distress syndrome (ARDS) is one of the most devastating complications of sepsis lacking of effective therapy. Mitochondrial dynamics undergoing continuous fusion and fission play a crucial role in mitochondrial structure and function. Fis1, as a small protein located on the outer membrane of mitochondria, has been thought to be an important protein mediated mitochondrial fission. During ARDS, alveolar macrophages suffer from increased oxidative stress and apoptosis, and also accompanied by disrupted mitochondrial dynamics. In addition, as one of the products of heme degradation catalyzed by heme oxygenase, carbon monoxide (CO) possesses powerful protective properties in vivo or in vitro models, such as anti-inflammatory, antioxidant and anti-apoptosis function. However, there is little evidence that CO alleviates oxidative stress damage through altering mitochondrial fission in alveolar macrophages. In the present study, our results showed that CO increased cell vitality, improved mitochondrial SOD activity, reduced reactive oxygen species (ROS) production and inhibited cell apoptosis in NR8383 exposed to LPS. Meanwhile, CO decreased the expression of Fis1, increased mitochondrial membrane potential and sustained elongation of mitochondria in LPS-incubated NR8383. Overall, our study underscored a critical role of CO in suppressing the expression of Fis1 and alleviating LPS- induced oxidative stress damage in alveolar macrophages. - Highlights: • LPS exposure triggered cell injury in NR8383. • CO alleviated LPS-induced oxidative stress damage in alveolar macrophages. • CO inhibited Fis1 levels and improved mitochondrial function in LPS-induced NR8383.

  19. A complex multilevel attack on Pseudomonas aeruginosa algT/U expression and AlgT/U activity results in the loss of alginate production

    DEFF Research Database (Denmark)

    Sautter, Robert; Ramos, Damaris; Schneper, Lisa

    2012-01-01

    Infection by the opportunistic pathogen Pseudomonas aeruginosa is a leading cause of morbidity and mortality seen in cystic fibrosis (CF) patients. This is mainly due to the genotypic and phenotypic changes of the bacteria that cause conversion from a typical nonmucoid to a mucoid form in the CF...... lung. Mucoid conversion is indicative of overproduction of a capsule-like polysaccharide called alginate. The alginate-overproducing (Alg+) mucoid phenotype seen in the CF isolates is extremely unstable. Low oxygen tension growth of mucoid variants readily selects for nonmucoid variants. The switching...... complementation and sequencing of one Group B sap mutant, sap22, revealed that the nonmucoid phenotype was due to the presence of a mutation in PA3257. PA3257 encodes a putative periplasmic protease. Mutation of PA3257 resulted in decreased algT/U expression. Thus, inhibition of algT/U is a primary mechanism...

  20. The Neurokinin-1 Receptor Contributes to the Early Phase of Lipopolysaccharide-Induced Fever via Stimulation of Peripheral Cyclooxygenase-2 Protein Expression in Mice

    Directory of Open Access Journals (Sweden)

    Eszter Pakai

    2018-02-01

    Full Text Available Neurokinin (NK signaling is involved in various inflammatory processes. A common manifestation of systemic inflammation is fever, which is usually induced in animal models with the administration of bacterial lipopolysaccharide (LPS. A role for the NK1 receptor was shown in LPS-induced fever, but the underlying mechanisms of how the NK1 receptor contributes to febrile response, especially in the early phase, have remained unknown. We administered LPS (120 µg/kg, intraperitoneally to mice with the Tacr1 gene, i.e., the gene encoding the NK1 receptor, either present (Tacr1+/+ or absent (Tacr1−/− and measured their thermoregulatory responses, serum cytokine levels, tissue cyclooxygenase-2 (COX-2 expression, and prostaglandin (PG E2 concentration. We found that the LPS-induced febrile response was attenuated in Tacr1−/− compared to their Tacr1+/+ littermates starting from 40 min postinfusion. The febrigenic effect of intracerebroventricularly administered PGE2 was not suppressed in the Tacr1−/− mice. Serum concentration of pyrogenic cytokines did not differ between Tacr1−/− and Tacr1+/+ at 40 min post-LPS infusion. Administration of LPS resulted in amplification of COX-2 mRNA expression in the lungs, liver, and brain of the mice, which was statistically indistinguishable between the genotypes. In contrast, the LPS-induced augmentation of COX-2 protein expression was attenuated in the lungs and tended to be suppressed in the liver of Tacr1−/− mice compared with Tacr1+/+ mice. The Tacr1+/+ mice responded to LPS with a significant surge of PGE2 production in the lungs, whereas Tacr1−/− mice did not. In conclusion, the NK1 receptor is necessary for normal fever genesis. Our results suggest that the NK1 receptor contributes to the early phase of LPS-induced fever by enhancing COX-2 protein expression in the periphery. These findings advance the understanding of the crosstalk between NK signaling and the “cytokine-COX-2

  1. Signal-transducing mechanisms of ketamine-caused inhibition of interleukin-1β gene expression in lipopolysaccharide-stimulated murine macrophage-like Raw 264.7 cells

    International Nuclear Information System (INIS)

    Chen, T.-L.; Chang, C.-C.; Lin, Y.-L.; Ueng, Y.-F.; Chen, R.-M.

    2009-01-01

    Ketamine may affect the host immunity. Interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) are pivotal cytokines produced by macrophages. This study aimed to evaluate the effects of ketamine on the regulation of inflammatory cytokine gene expression, especially IL-1β, in lipopolysaccharide (LPS)-activated murine macrophage-like Raw 264.7 cells and its possible signal-transducing mechanisms. Administration of Raw 264.7 cells with a therapeutic concentration of ketamine (100 μM), LPS, or a combination of ketamine and LPS for 1, 6, and 24 h was not cytotoxic to macrophages. Exposure to 100 μM ketamine decreased the binding affinity of LPS and LPS-binding protein but did not affect LPS-induced RNA and protein synthesis of TLR4. Treatment with LPS significantly increased IL-1β, IL-6, and TNF-α gene expressions in Raw 264.7 cells. Ketamine at a clinically relevant concentration did not affect the synthesis of these inflammatory cytokines, but significantly decreased LPS-caused increases in these cytokines. Immunoblot analyses, an electrophoretic mobility shift assay, and a reporter luciferase activity assay revealed that ketamine significantly decreased LPS-induced translocation and DNA binding activity of nuclear factor-kappa B (NFκB). Administration of LPS sequentially increased the phosphorylations of Ras, Raf, MEK1/2, ERK1/2, and IKK. However, a therapeutic concentration of ketamine alleviated such augmentations. Application of toll-like receptor 4 (TLR4) small interfering (si)RNA reduced cellular TLR4 amounts and ameliorated LPS-induced RAS activation and IL-1β synthesis. Co-treatment with ketamine and TLR4 siRNA synergistically ameliorated LPS-caused enhancement of IL-1β production. Results of this study show that a therapeutic concentration of ketamine can inhibit gene expression of IL-1β possibly through suppressing TLR4-mediated signal-transducing phosphorylations of Ras, Raf, MEK1/2, ERK1/2, and IKK and subsequent translocation and

  2. Role of TLR4/NADPH oxidase/ROS-activated p38 MAPK in VCAM-1 expression induced by lipopolysaccharide in human renal mesangial cells

    Directory of Open Access Journals (Sweden)

    Lee I-Ta

    2012-11-01

    Full Text Available Abstract Background In bacteria-induced glomerulonephritis, Toll-like receptor 4 (TLR4 activation by lipopolysaccharide (LPS, a key component of the outer membranes of Gram-negative bacteria can increase oxidative stress and the expression of vascular cell adhesion molecule-1 (VCAM-1, which recruits leukocytes to the glomerular mesangium. However, the mechanisms underlying VCAM-1 expression induced by LPS are still unclear in human renal mesangial cells (HRMCs. Results We demonstrated that LPS induced VCAM-1 mRNA and protein levels associated with an increase in the promoter activity of VCAM-1, determined by Western blot, RT-PCR, and promoter assay. LPS-induced responses were inhibited by transfection with siRNAs of TLR4, myeloid differentiation factor 88 (MyD88, Nox2, Nox4, p47phox, c-Src, p38 MAPK, activating transcription factor 2 (ATF2, and p300 or pretreatment with the inhibitors of reactive oxygen species (ROS, edaravone, NADPH oxidase [apocynin (APO or diphenyleneiodonium chloride (DPI], c-Src (PP1, p38 MAPK (SB202190, and p300 (GR343. LPS induced NADPH oxidase activation, ROS production, and p47phox translocation from the cytosol to the membrane, which were reduced by PP1 or c-Src siRNA. We observed that LPS induced TLR4, MyD88, c-Src, and p47phox complex formation determined by co-immunoprecipitation and Western blot. We further demonstrated that LPS stimulated ATF2 and p300 phosphorylation and complex formation via a c-Src/NADPH oxidase/ROS/p38 MAPK pathway. Up-regulation of VCAM-1 led to enhancing monocyte adhesion to HRMCs challenged with LPS, which was inhibited by siRNAs of c-Src, p47phox, p38 MAPK, ATF2, and p300 or pretreatment with an anti-VCAM-1 neutralizing antibody. Conclusions In HRMCs, LPS-induced VCAM-1 expression was, at least in part, mediated through a TLR4/MyD88/ c-Src/NADPH oxidase/ROS/p38 MAPK-dependent p300 and ATF2 pathway associated with recruitment of monocyte adhesion to kidney. Blockade of these pathways may

  3. Myocardial fibrosis induced by exposure to subclinical lipopolysaccharide is associated with decreased miR-29c and enhanced NOX2 expression in mice.

    Directory of Open Access Journals (Sweden)

    Wilbur Y W Lew

    Full Text Available Exposure to subclinical levels of lipopolysaccharide (LPS occurs commonly and is seemingly well tolerated. However, recurrent LPS exposure induces cardiac fibrosis over 2 to 3 months in a murine model, not mediated by the renin-angiotensin system. Subclinical LPS induces cardiac fibrosis by unique mechanisms.In C57/Bl6 mice, LPS (10 mg/kg or saline (control were injected intraperitoneally once a week for 1-4 weeks. Mice showed no signs of distress, change in activity, appetite, or weight loss. Mice were euthanized after 3 days, 1, 2, or 4 weeks to measure cardiac expression of fibrosis-related genes and potential mediators (measured by QRT-PCR, including micro-RNA (miR and NADPH oxidase (NOX. Collagen fraction area of the left ventricle was measured with picrosirius red staining. Cardiac fibroblasts isolated from adult mouse hearts were incubated with 0, 0.1, 1.0 or 10 ng/ml LPS for 48 hours.Cardiac miR expression profiling demonstrated decreased miR-29c after 3 and 7 days following LPS, which were confirmed by QRT-PCR. The earliest changes in fibrosis-related genes and mediators that occurred 3 days after LPS were increased cardiac expression of TIMP-1 and NOX-2 (but not of NOX-4. This persisted at 1 and 2 weeks, with additional increases in collagen Iα1, collagen IIIα1, MMP2, MMP9, TIMP1, TIMP2, and periostin. There was no change in TGF-β or connective tissue growth factor. Collagen fraction area of the left ventricle increased after 2 and 4 weeks of LPS. LPS decreased miR-29c and increased NOX-2 in isolated cardiac fibroblasts.Recurrent exposure to subclinical LPS induces cardiac fibrosis after 2-4 weeks. Early changes 3 days after LPS were decreased miR-29c and increased NOX2 and TIMP1, which persisted at 1 and 2 weeks, along with widespread activation of fibrosis-related genes. Decreased miR-29c and increased NOX2, which induce cardiac fibrosis in other conditions, may uniquely mediate LPS-induced cardiac fibrosis.

  4. Mucoid Pseudomonas aeruginosa isolates maintain the biofilm formation capacity and the gene expression profiles during the chronic lung infection of CF patients

    DEFF Research Database (Denmark)

    Lee, Bao le ri; Schjerling, Charlotte K.; Kirkby, Nikolai

    2011-01-01

    Phenotypic and genotypic diversifications of Pseudomonas aeruginosa in the airways of patients with cystic fibrosis (CF) promote long-term survival of bacteria during chronic lung infection. Twelve clonally related, sequential mucoid and non-mucoid paired P. aeruginosa isolates obtained from three......-mucoid isolates observed in this particular P. aeruginosa clone reflects different adaptation strategies used by these two phenotypes in the different niches of the CF lung environment....

  5. The biofilm-specific antibiotic resistance gene ndvB is important for expression of ethanol oxidation genes in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Beaudoin, Trevor; Zhang, Li; Hinz, Aaron J; Parr, Christopher J; Mah, Thien-Fah

    2012-06-01

    Bacteria growing in biofilms are responsible for a large number of persistent infections and are often more resistant to antibiotics than are free-floating bacteria. In a previous study, we identified a Pseudomonas aeruginosa gene, ndvB, which is important for the formation of periplasmic glucans. We established that these glucans function in biofilm-specific antibiotic resistance by sequestering antibiotic molecules away from their cellular targets. In this study, we investigate another function of ndvB in biofilm-specific antibiotic resistance. DNA microarray analysis identified 24 genes that were responsive to the presence of ndvB. A subset of 20 genes, including 8 ethanol oxidation genes (ercS', erbR, exaA, exaB, eraR, pqqB, pqqC, and pqqE), was highly expressed in wild-type biofilm cells but not in ΔndvB biofilms, while 4 genes displayed the reciprocal expression pattern. Using quantitative real-time PCR, we confirmed the ndvB-dependent expression of the ethanol oxidation genes and additionally demonstrated that these genes were more highly expressed in biofilms than in planktonic cultures. Expression of erbR in ΔndvB biofilms was restored after the treatment of the biofilm with periplasmic extracts derived from wild-type biofilm cells. Inactivation of ethanol oxidation genes increased the sensitivity of biofilms to tobramycin. Together, these results reveal that ndvB affects the expression of multiple genes in biofilms and that ethanol oxidation genes are linked to biofilm-specific antibiotic resistance.

  6. Lipopolysaccharide derived from the rumen down-regulates stearoyl-CoA desaturase 1 expression and alters fatty acid composition in the liver of dairy cows fed a high-concentrate diet.

    Science.gov (United States)

    Xu, Tianle; Tao, Hui; Chang, Guangjun; Zhang, Kai; Xu, Lei; Shen, Xiangzhen

    2015-03-07

    Dairy cows are often fed a high-concentrate diet to meet lactating demands, yet long-term concentrate feeding induces subacute ruminal acidosis (SARA) and leads to a decrease in milk fat. Stearoyl-CoA desaturase1 (SCD1) participates in fatty acid biosynthesis in the liver of lactating ruminants. Here, we conducted this study to investigate the impact of lipopolysaccharide derived from the rumen on SCD1 expression and on fatty acid composition in the liver of dairy cows fed a high-concentrate diet. Eight multiparous mid-lactating Holstein cows (455 ± 28 kg) were randomly assigned into two groups in the experiment and were fed a low-concentrate diet (LC) or high-concentrate diet (HC) for 18 weeks. The results showed that the total volatile fatty acids and lactic acid accumulated in the rumen, leading to a decreased rumen pH and elevated lipopolysaccharides (LPSs) in the HC group. The long chain fatty acid profile in the rumen and hepatic vein was remarkably altered in the animals fed the HC diet. The triglyceride (TG), non-esterified fatty acid (NEFA) and total cholesterol (TCH) content in the plasma was significantly decreased, whereas plasma glucose and insulin levels were increased. The expression of SCD1 in the liver was significantly down-regulated in the HC group. In regards to transcriptional regulators, the expression of sterol regulatory element binding transcription factors (SREBF1c, SREBF2) and SREBP cleavage activating protein (SCAP) was down-regulated, while peroxisome proliferator-activated receptor α (PPARα) was up-regulated. These data indicate that lipopolysaccharide derived from the rumen down-regulates stearoyl-CoA desaturase 1 expression and alters fatty acid composition in the liver of dairy cows fed a high-concentrate diet.

  7. Cloning, over-expression and purification of Pseudomonas aeruginosa murC encoding uridine diphosphate N-acetylmuramate: L-alanine ligase.

    Science.gov (United States)

    El Zoeiby, A; Sanschagrin, F; Lamoureux, J; Darveau, A; Levesque, R C

    2000-02-15

    We cloned and sequenced the murC gene from Pseudomonas aeruginosa encoding a protein of 53 kDa. Multiple alignments with 20 MurC peptide sequences from different bacteria confirmed the presence of highly conserved regions having sequence identities ranging from 22-97% including conserved motifs for ATP-binding and the active site of the enzyme. Genetic complementation was done in Escherichia coli (murCts) suppressing the lethal phenotype. The murC gene was subcloned into the expression vector pET30a and overexpressed in E. coli BL21(lambdaDE3). Three PCR cloning strategies were used to obtain the three recombinant plasmids for expression of the native MurC, MurC His-tagged at N-terminal and at C-terminal, respectively. MurC His-tagged at C-terminal was chosen for large scale production and protein purification in the soluble form. The purification was done in a single chromatographic step on an affinity nickel column and obtained in mg quantities at 95% homogeneity. MurC protein was used to produce monoclonal antibodies for epitope mapping and for assay development in high throughput screenings. Detailed studies of MurC and other genes of the bacterial cell cycle will provide the reagents and strain constructs for high throughput screening and for design of novel antibacterials.

  8. Zingerone suppresses liver inflammation induced by antibiotic mediated endotoxemia through down regulating hepatic mRNA expression of inflammatory markers in Pseudomonas aeruginosa peritonitis mouse model.

    Directory of Open Access Journals (Sweden)

    Lokender Kumar

    Full Text Available Antibiotic-induced endotoxin release is associated with high mortality rate even when appropriate antibiotics are used for the treatment of severe infections in intensive care units. Since liver is involved in systemic clearance and detoxification of endotoxin hence it becomes a primary target organ for endotoxin mediated inflammation. Currently available anti-inflammatory drugs give rise to serious side effects. Hence, there is an urgent need for safe and effective anti-inflammatory therapy. It is likely that anti-inflammatory phytochemicals and neutraceutical agents may have the potential to reduce the endotoxin mediated inflammation and complications associated with endotoxin release. Keeping this in mind, the present study was planned to evaluate the hepatoprotective potential of zingerone (active compound of zingiber officinale against liver inflammation induced by antibiotic mediated endotoxemia. The selected antibiotics capable of releasing high content of endotoxin were employed for their in vivo efficacy in P.aeruginosa peritonitis model. Released endotoxin induced inflammation and zingerone as co-anti-inflammatory therapy significantly reduced inflammatory response. Improved liver histology and reduced inflammatory markers MDA, RNI, MPO, tissue damage markers (AST, ALT, ALP and inflammatory cytokines (MIP-2, IL-6 and TNF-α were indicative of therapeutic potential of zingerone. The mechanism of action of zingerone may be related to significant inhibition of the mRNA expression of inflammatory markers (TLR4, RelA, NF-kB2, TNF- α, iNOS, COX-2 indicating that zingerone interferes with cell signalling pathway and suppresses hyper expression of cell signaling molecules of inflammatory pathway. Zingerone therapy significantly protected liver from endotoxin induced inflammatory damage by down regulating biochemical as well as molecular markers of inflammation. In conclusion, this study provides evidence that zingerone is a potent anti

  9. Zingerone suppresses liver inflammation induced by antibiotic mediated endotoxemia through down regulating hepatic mRNA expression of inflammatory markers in Pseudomonas aeruginosa peritonitis mouse model.

    Science.gov (United States)

    Kumar, Lokender; Chhibber, Sanjay; Harjai, Kusum

    2014-01-01

    Antibiotic-induced endotoxin release is associated with high mortality rate even when appropriate antibiotics are used for the treatment of severe infections in intensive care units. Since liver is involved in systemic clearance and detoxification of endotoxin hence it becomes a primary target organ for endotoxin mediated inflammation. Currently available anti-inflammatory drugs give rise to serious side effects. Hence, there is an urgent need for safe and effective anti-inflammatory therapy. It is likely that anti-inflammatory phytochemicals and neutraceutical agents may have the potential to reduce the endotoxin mediated inflammation and complications associated with endotoxin release. Keeping this in mind, the present study was planned to evaluate the hepatoprotective potential of zingerone (active compound of zingiber officinale) against liver inflammation induced by antibiotic mediated endotoxemia. The selected antibiotics capable of releasing high content of endotoxin were employed for their in vivo efficacy in P.aeruginosa peritonitis model. Released endotoxin induced inflammation and zingerone as co-anti-inflammatory therapy significantly reduced inflammatory response. Improved liver histology and reduced inflammatory markers MDA, RNI, MPO, tissue damage markers (AST, ALT, ALP) and inflammatory cytokines (MIP-2, IL-6 and TNF-α) were indicative of therapeutic potential of zingerone. The mechanism of action of zingerone may be related to significant inhibition of the mRNA expression of inflammatory markers (TLR4, RelA, NF-kB2, TNF- α, iNOS, COX-2) indicating that zingerone interferes with cell signalling pathway and suppresses hyper expression of cell signaling molecules of inflammatory pathway. Zingerone therapy significantly protected liver from endotoxin induced inflammatory damage by down regulating biochemical as well as molecular markers of inflammation. In conclusion, this study provides evidence that zingerone is a potent anti

  10. Over-expression and siRNA of a novel environmental lipopolysaccharide-responding gene on the cell cycle of the human hepatoma-derived cell line HepG2

    International Nuclear Information System (INIS)

    Du Kejun; Chai Yubo; Hou Lichao; Chang Wenhui; Chen Suming; Luo Wenjing; Cai Tongjian; Zhang Xiaonan; Chen Nanchun; Chen Yaoming; Chen Jingyuan

    2008-01-01

    Lipopolysaccharide (LPS) is the toxic determinant for Gram-negative bacterium infection. The individual response to LPS was related to its gene background. It is necessary to identify new molecules and signaling transduction pathways about LPS. The present study was undertaken to evaluate the effects of a novel environmental lipopolysaccharide-responding (Elrg) gene on the regulation of proliferation and cell cycle of the hepatoma-derived cell line, HepG2. By means of RT-PCR, the new molecule of Elrg was generated from a human dental pulp cell cDNA library. Expression level of Elrg in HepG2 cells was remarkably upgraded by the irritation of LPS. Localization of Elrg in HepG2 cells was positioned mainly in cytoplasm. HepG2 cells were markedly arrested in the G1 phase by over-expressing Elrg. The percentage of HepG2 cells in G1 phase partly decreased after Elrg-siRNA. In conclusion, Elrg is probably correlative with LPS responding. Elrg is probably a new protein in cytoplasm which plays an important role in regulating cell cycle. The results will deepen our understanding about the potential effects of Elrg on the human hepatoma-derived cell line HepG2

  11. Structure of bacterial lipopolysaccharides.

    Science.gov (United States)

    Caroff, Martine; Karibian, Doris

    2003-11-14

    Bacterial lipopolysaccharides are the major components of the outer surface of Gram-negative bacteria They are often of interest in medicine for their immunomodulatory properties. In small amounts they can be beneficial, but in larger amounts they may cause endotoxic shock. Although they share a common architecture, their structural details exert a strong influence on their activity. These molecules comprise: a lipid moiety, called lipid A, which is considered to be the endotoxic component, a glycosidic part consisting of a core of approximately 10 monosaccharides and, in "smooth-type" lipopolysaccharides, a third region, named O-chain, consisting of repetitive subunits of one to eight monosaccharides responsible for much of the immunospecificity of the bacterial cell.

  12. Gentamicin in Pseudomonas aeruginosa

    African Journals Online (AJOL)

    infections by Ps. aeruginosa is contra-indicated. In our study only 2,3 % of the Ps. aeruginosa strains were resistant to gentamicin (MIC 25 Ilg/ml). In view of the synergy reported for combined gentamicin and carbeni- cillin therapy," a combination of these two drugs may be recommended in the treatment of all Pseudomonas.

  13. Inhibitory effects of tocopherols on expression of the cyclooxygenase-2 gene in RAW264.7 cells stimulated by lipopolysaccharide, tumor necrosis factor-α or Porphyromonas gingivalis fimbriae.

    Science.gov (United States)

    Murakami, Yukio; Kawata, Akifumi; Koh, Teho; Seki, Yuya; Tamura, Seiko; Katayama, Tadashi; Fujisawa, Seiichiro

    2013-01-01

    Tocopherols, which include α-, β-, γ-, and δ-tocopherol, protect cells against harmful free radicals and play an important role in preventing many human diseases such as cancer, inflammatory disorders, and ageing itself. However, the causal relationships between periodontal or oral chronic diseases and tocopherols have not been sufficiently studied. The present study investigated the inhibitory effects of these compounds on the expression of cyclooxygenase-2 (COX2) mRNA in RAW264.7 cells stimulated with lipopolysaccharide (LPS), tumor necrosis factor-α (TNFα) or fimbriae of Poryphyromonas gingivalis (Pg), an oral anaerobe. The cytotoxicity (EC₅₀) of tocopherols toward RAW cells was determined using a cell counting kit (CCK-8). The regulatory effect of these compounds on the expression of COX2 mRNA stimulated with LPS, TNFα or Pg fimbriae was investigated using real-time polymerase chain reaction (PCR). Each tocopherol had similarly low cytotoxicity. COX2 gene expression in RAW cells after exposure to the three different macrophage activators was inhibited by the tocopherols (ptocopherol, β-, γ- and δ-tocopherol exhibited greater inhibitory effects (pTocopherols exhibit anti-inflammatory activity, and β-, γ- and δ-tocopherol have particularly more potent anti-inflammatory activity than α-tocopherol. Tocopherols may have potential utility for prevention of periodontal and chronic oral diseases.

  14. Histone deacetylase inhibitors restore IL-10 expression in lipopolysaccharide-induced cell inflammation and reduce IL-1β and IL-6 production in breast silicone implant in C57BL/6J wild-type murine model.

    Science.gov (United States)

    Di Liddo, Rosa; Valente, Sergio; Taurone, Samanta; Zwergel, Clemens; Marrocco, Biagina; Turchetta, Rosaria; Conconi, Maria Teresa; Scarpa, Carlotta; Bertalot, Thomas; Schrenk, Sandra; Mai, Antonello; Artico, Marco

    2016-01-20

    Among epigenetic enzymes, histone deacetylases (HDACs) are responsible for regulating the expression of an extensive array of genes by reversible deacetylation of nuclear histones as well as a large number of non-histone proteins. Initially proposed for cancer therapy, recently the interest for HDAC inhibitors (HDACi) as orally active, safe, and anti-inflammatory agents is rising due to their ability in reducing the severity of inflammatory and autoimmune diseases. In particular, selective HDAC3, HDAC6, and HDAC8 inhibitors have been described to downregulate the expression of pro-inflammatory cytokines (TNF-α, TGF-β, IL-1β, and IL-6). Herein, using KB31, C2C12, and 3T3-J2 cell lines, we demonstrated that, under lipopolysaccharide-induced in vitro inflammation, HDAC3/6/8 inhibitor MC2625 and HDAC6-selective inhibitor MC2780 were effective at a concentration of 30 ng/mL to downregulate mRNA expression of pro-inflammatory cytokines (IL-1β and IL-6) and to promote the transcription of IL-10 gene, without affecting the cell viability. Afterwards, we investigated by immunohistochemistry the activity of MC2625 and MC2780 at a concentration of 60 ng/kg animal weight to regulate silicone-triggered immune response in C57BL/6J female mice. Our findings evidenced the ability of such inhibitors to reduce host inflammation in silicone implants promoting a thickness reduction of peri-implant fibrous capsule, upregulating IL-10 expression, and reducing the production of both IL-1β and IL-6. These results underline the potential application of MC2625 and MC2780 in inflammation-related diseases.

  15. Pseudomonas aeruginosa toxin ExoU induces a PAF-dependent impairment of alveolar fibrin turnover secondary to enhanced activation of coagulation and increased expression of plasminogen activator inhibitor-1 in the course of mice pneumosepsis

    Directory of Open Access Journals (Sweden)

    Suassuna José HR

    2011-08-01

    Full Text Available Abstract Background ExoU, a Pseudomonas aeruginosa cytotoxin with phospholipase A2 activity, was shown to induce vascular hyperpermeability and thrombus formation in a murine model of pneumosepsis. In this study, we investigated the toxin ability to induce alterations in pulmonary fibrinolysis and the contribution of the platelet activating factor (PAF in the ExoU-induced overexpression of plasminogen activator inhibitor-1 (PAI-1. Methods Mice were intratracheally instilled with the ExoU producing PA103 P. aeruginosa or its mutant with deletion of the exoU gene. After 24 h, animal bronchoalveolar lavage fluids (BALF were analyzed and lung sections were submitted to fibrin and PAI-1 immunohistochemical localization. Supernatants from A549 airway epithelial cells and THP-1 macrophage cultures infected with both bacterial strains were also analyzed at 24 h post-infection. Results In PA103-infected mice, but not in control animals or in mice infected with the bacterial mutant, extensive fibrin deposition was detected in lung parenchyma and microvasculature whereas mice BALF exhibited elevated tissue factor-dependent procoagulant activity and PAI-1 concentration. ExoU-triggered PAI-1 overexpression was confirmed by immunohistochemistry. In in vitro assays, PA103-infected A549 cells exhibited overexpression of PAI-1 mRNA. Increased concentration of PAI-1 protein was detected in both A549 and THP-1 culture supernatants. Mice treatment with a PAF antagonist prior to PA103 infection reduced significantly PAI-1 concentrations in mice BALF. Similarly, A549 cell treatment with an antibody against PAF receptor significantly reduced PAI-1 mRNA expression and PAI-1 concentrations in cell supernatants, respectively. Conclusion ExoU was shown to induce disturbed fibrin turnover, secondary to enhanced procoagulant and antifibrinolytic activity during P. aeruginosa pneumosepsis, by a PAF-dependent mechanism. Besides its possible pathophysiological relevance, in

  16. Statistical Analysis of Pseudomonas aeruginosa Biofilm Development: Impact of Mutations in Genes Involved in Twitching Motility, Cell-to-Cell Signaling, and Stationary-Phase Sigma Factor Expression

    DEFF Research Database (Denmark)

    Heydorn, Arne; Ersbøll, Bjarne Kjær; Kato, Junichi

    2002-01-01

    of variance model comprising the four P. aeruginosa strains, five time points (55, 98, 146, 242, and 314 h), and three independent rounds of biofllm experiments. The results showed that the wild type, the DeltapilHIJK mutant, and the rpoS mutant display conspicuously different types of temporal biofilm...... development, whereas the lasI mutant was indistinguishable from the wild type at all time points. The wild type and the lasI mutant formed uniform, densely packed biofilms. The rpoS mutant formed densely packed biofilms that were significantly thicker than those of the wild type, whereas the Deltapil...

  17. Identification of transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) as a novel factor for TNF-α expression upon lipopolysaccharide stimulation in human monocytes.

    Science.gov (United States)

    Murata, H; Hattori, T; Maeda, H; Takashiba, S; Takigawa, M; Kido, J; Nagata, T

    2015-08-01

    Tumor necrosis factor alpha (TNF-α) is a major cytokine implicated in various inflammatory diseases. The nature of the nuclear factors associated with human TNF-α gene regulation is not well elucidated. We previously identified a novel region located from -550 to -487 in human TNF-α promoter that did not contain the reported binding sites for nuclear factor kappa B (NF-κB) but showed lipopolysaccharide (LPS)-induced transcriptional activity. The purpose of this study is to identify novel factors that bind to the promoter region and regulate TNF-α expression. To identify DNA-binding proteins that bound to the target region of TNF-α promoter, a cDNA library from LPS-stimulated human monocytic cell line THP-1 was screened using a yeast one-hybrid system. Cellular localizations of the DNA-binding protein in the cells were examined by subcellular immunocytochemistry. Nuclear amounts of the protein in LPS-stimulated THP-1 cells were identified by western blot analysis. Expression of mRNA of the protein in the cells was quantified by real-time polymerase chain reaction. Electrophoretic mobility shift assays were performed to confirm the DNA-binding profile. Overexpression of the protein and knockdown of the gene were also performed to investigate the role for TNF-α expression. Several candidates were identified from the cDNA library and transactivation-responsive DNA-binding protein 43 (TARDBP43; TDP-43) was focused on. Western blot analysis revealed that nuclear TDP-43 protein was increased in the LPS-stimulated THP-1 cells. Expression of TDP-43 mRNA was already enhanced before TNF-α induction by LPS. Electrophoretic mobility shift assay analysis showed that nuclear extracts obtained by overexpressing FLAG-tagged TDP-43 bound to the -550 to -487 TNF-α promoter fragments. Overexpression of TDP-43 in THP-1 cells resulted in an increase of TNF-α expression. Knockdown of TDP-43 in THP-1 cells downregulated TNF-α expression. We identified TDP-43 as one of the novel

  18. Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa.

    Science.gov (United States)

    Osthoff, Michael; Brown, Karl D; Kong, David C M; Daniell, Mark; Eisen, Damon P

    2014-01-01

    Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT-PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed.

  19. Synergistic Efficacy of Aedes aegypti Antimicrobial Peptide Cecropin A2 and Tetracycline against Pseudomonas aeruginosa

    Science.gov (United States)

    Zheng, Zhaojun; Tharmalingam, Nagendran; Liu, Qingzhong; Kim, Wooseong; Fuchs, Beth Burgwyn; Zhang, Rijun; Vilcinskas, Andreas

    2017-01-01

    ABSTRACT The increasing prevalence of antibiotic resistance has created an urgent need for alternative drugs with new mechanisms of action. Antimicrobial peptides (AMPs) are promising candidates that could address the spread of multidrug-resistant bacteria, either alone or in combination with conventional antibiotics. We studied the antimicrobial efficacy and bactericidal mechanism of cecropin A2, a 36-residue α-helical cationic peptide derived from Aedes aegypti cecropin A, focusing on the common pathogen Pseudomonas aeruginosa. The peptide showed little hemolytic activity and toxicity toward mammalian cells, and the MICs against most clinical P. aeruginosa isolates were 32 to 64 μg/ml, and its MICs versus other Gram-negative bacteria were 2 to 32 μg/ml. Importantly, cecropin A2 demonstrated synergistic activity against P. aeruginosa when combined with tetracycline, reducing the MICs of both agents by 8-fold. The combination was also effective in vivo in the P. aeruginosa/Galleria mellonella model (P < 0.001). We found that cecropin A2 bound to P. aeruginosa lipopolysaccharides, permeabilized the membrane, and interacted with the bacterial genomic DNA, thus facilitating the translocation of tetracycline into the cytoplasm. In summary, the combination of cecropin A2 and tetracycline demonstrated synergistic antibacterial activity against P. aeruginosa in vitro and in vivo, offering an alternative approach for the treatment of P. aeruginosa infections. PMID:28483966

  20. Lipopolysaccharide induces VCAM-1 expression and neutrophil adhesion to human tracheal smooth muscle cells: Involvement of Src/EGFR/PI3-K/Akt pathway

    International Nuclear Information System (INIS)

    Lin, W.-N.; Luo, S.-F.; Wu, C.-B.; Lin, C.-C.; Yang, C.-M.

    2008-01-01

    In our previous study, LPS has been shown to induce vascular cell adhesion molecule-1(VCAM-1) expression through MAPKs and NF-κB in human tracheal smooth muscle cells (HTSMCs). In addition to these pathways, the non-receptor tyrosine kinases (Src), EGF receptor (EGFR), and phosphatidylinositol 3-kinase (PI3K) have been shown to be implicated in the expression of several inflammatory target proteins. Here, we reported that LPS-induced up-regulation of VCAM-1 enhanced the adhesion of neutrophils onto HTSMC monolayer, which was inhibited by LY294002 and wortmannin. LPS stimulated phosphorylation of protein tyrosine kinases including Src, PYK2, and EGFR, which were further confirmed using specific anti-phospho-Src, PYK2, or EGFR Ab, respectively, revealed by Western blotting. LPS-stimulated Src, PYK2, EGFR, and Akt phosphorylation and VCAM-1 expression were attenuated by the inhibitors of Src (PP1), EGFR (AG1478), PI3-K (LY294002 and wortmannin), and Akt (SH-5), respectively, or transfection with siRNAs of Src or Akt and shRNA of p110. LPS-induced VCAM-1 expression was also blocked by pretreatment with curcumin (a p300 inhibitor) or transfection with p300 siRNA. LPS-stimulated Akt activation translocated into nucleus and associated with p300 and VCAM-1 promoter region was further confirmed by immunofluorescence, immunoprecipitation, and chromatin immunoprecipitation assays. This association of Akt and p300 to VCAM-1 promoter was inhibited by pretreatment with PP1, AG1478, wortmannin, and SH-5. LPS-induced p300 activation enhanced VCAM-1 promoter activity and VCAM-1 mRNA expression. These results suggested that in HTSMCs, Akt phosphorylation mediated through transactivation of Src/PYK2/EGFR promoted the transcriptional p300 activity and eventually led to VCAM-1 expression induced by LPS

  1. Tumor necrosis factor receptor-associated factor 6 (TRAF6) participates in anti-lipopolysaccharide factors (ALFs) gene expression in mud crab.

    Science.gov (United States)

    Sun, Wan-Wei; Zhang, Xin-Xu; Wan, Wei-Song; Wang, Shu-Qi; Wen, Xiao-Bo; Zheng, Huai-Ping; Zhang, Yue-Ling; Li, Sheng-Kang

    2017-02-01

    Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a key cytoplasm signal adaptor that mediates signals activated by tumor necrosis factor receptor (TNFR) superfamily and the Interleukin-1 receptor/Toll-like receptor (IL-1/TLR) superfamily. The full-length 2492 bp TRAF6 (Sp-TRAF6) from Scylla paramamosain contains 1800 bp of open reading frame (ORF) encoding 598 amino acids, including an N-terminal RING-type zinc finger, two TRAF-type zinc fingers and a conserved C-terminal meprin and TRAF homology (MATH) domain. Multiple alignment analysis shows that the putative amino acid sequence of Sp-TRAf6 has highest identity of 88% with Pt-TRAF6 from Portunus trituberculatus, while the similarity of Sp-TRAF6 with other crustacean sequences was 54-55%. RT-PCR analysis indicated that Sp-TRAF6 transcripts were predominantly expressed in the hepatopancreas and stomach, whereas it was barely detected in the heart and hemocytes in our study. Moreover, Sp-TRAF6 transcripts were significantly up-regulated after Vibrio parahemolyticus and LPS challenges. RNA interference assay was carried out used by siRNA to investigate the genes expression patterns regulated by Sp-TRAF6. The qRT-PCR results showed that silencing Sp-TRAF6 gene could inhibit SpALF1, SpALF2, SpALF5 and SpALF6 expression in hemocytes, while inhibit SpALF1, SpALF3, SpALF4, SpALF5 and SpALF6 expression in hepatopancreas. Taken together, the acute-phase response to immune challenges and the inhibition of SpALFs gene expression indicate that Sp-TRAF6 plays an important role in host defense against pathogen invasions via regulation of ALF gene expression in S. paramamosain. Copyright © 2016. Published by Elsevier Ltd.

  2. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  3. mRNA expression of genes involved in inflammation and haemostasis in equine fibroblast-like synoviocytes following exposure to lipopolysaccharide, fibrinogen and thrombin

    DEFF Research Database (Denmark)

    Andreassen, Stine Mandrup; Berg, Lise Charlotte; Nielsen, Søren Saxmose

    2015-01-01

    Background: Studies in humans have shown that haemostatic and inflammatory pathways both play important roles in the pathogenesis of joint disease. The aim of this study was to assess mRNA expression of haemostatic and inflammatory factors in cultured equine fibroblast-like synoviocytes exposed t...

  4. Localization of macrophage inflammatory protein : Macrophage inflammatory PROTEIN-1 expression in rat brain after peripheral administration of lipopolysaccharide and focal cerebral ischemia

    NARCIS (Netherlands)

    Gourmala, NG; Limonta, S; Bochelen, D; Sauter, A; Boddeke, HWGM

    Macrophage inflammatory protein is a member of the C-C subfamily of chemokines, which exhibits, in addition to proinflammatory activities, a potent endogenous pyrogen activity. In this study, we analysed the time-course of expression and cellular source of macrophage inflammatory protein-1 alpha and

  5. Cyclophilin B attenuates the expression of TNF-α in lipopolysaccharide-stimulated macrophages through the induction of B cell lymphoma-3.

    Science.gov (United States)

    Marcant, Adeline; Denys, Agnès; Melchior, Aurélie; Martinez, Pierre; Deligny, Audrey; Carpentier, Mathieu; Allain, Fabrice

    2012-08-15

    Extracellular cyclophilin A (CyPA) and CyPB have been well described as chemotactic factors for various leukocyte subsets, suggesting their contribution to inflammatory responses. Unlike CyPA, CyPB accumulates in extracellular matrixes, from which it is released by inflammatory proteases. Hence, we hypothesized that it could participate in tissue inflammation by regulating the activity of macrophages. In the current study, we confirmed that CyPB initiated in vitro migration of macrophages, but it did not induce production of proinflammatory cytokines. In contrast, pretreatment of macrophages with CyPB attenuated the expression of inflammatory mediators induced by LPS stimulation. The expression of TNF-α mRNA was strongly reduced after exposure to CyPB, but it was not accompanied by significant modification in LPS-induced activation of MAPK and NF-κB pathways. LPS activation of a reporter gene under the control of TNF-α gene promoter was also markedly decreased in cells treated with CyPB, suggesting a transcriptional mechanism of inhibition. Consistent with this hypothesis, we found that CyPB induced the expression of B cell lymphoma-3 (Bcl-3), which was accompanied by a decrease in the binding of NF-κB p65 to the TNF-α promoter. As expected, interfering with the expression of Bcl-3 restored cell responsiveness to LPS, thus confirming that CyPB acted by inhibiting initiation of TNF-α gene transcription. Finally, we found that CyPA was not efficient in attenuating the production of TNF-α from LPS-stimulated macrophages, which seemed to be due to a modest induction of Bcl-3 expression. Collectively, these findings suggest an unexpected role for CyPB in attenuation of the responses of proinflammatory macrophages.

  6. Experimental Pseudomonas aeruginosa mediated rhino sinusitis in mink

    DEFF Research Database (Denmark)

    Kirkeby, S.; Hammer, A. S.; Høiby, N.

    2017-01-01

    The nasal and sinus cavities in children may serve as reservoirs for microorganisms that cause recurrent and chronic lung infections. This study evaluates whether the mink can be used as an animal model for studying Pseudomonas aeruginosa mediated rhino-sinusitis since there is no suitable...... in the infected mink shows features of carbohydrate expression comparable to what has been described in the respiratory system after Pseudomonas aeruginosa infection in humans. It is suggested that the mink is suitable for studying Pseudomonas aeruginosa mediated rhino-sinusitis....

  7. Lipopolysaccharide inhibits colonic biotin uptake via interference with membrane expression of its transporter: a role for a casein kinase 2-mediated pathway.

    Science.gov (United States)

    Lakhan, Ram; Said, Hamid M

    2017-04-01

    Biotin (vitamin B7), an essential micronutrient for normal cellular functions, is obtained from both dietary sources as well as gut microbiota. Absorption of biotin in both the small and large intestine is via a carrier-mediated process that involves the sodium-dependent multivitamin transporter (SMVT). Although different physiological and molecular aspects of intestinal biotin uptake have been delineated, nothing is known about the effect of LPS on the process. We addressed this issue using in vitro (human colonic epithelial NCM460 cells) and in vivo (mice) models of LPS exposure. Treating NCM460 cells with LPS was found to lead to a significant inhibition in carrier-mediated biotin uptake. Similarly, administration of LPS to mice led to a significant inhibition in biotin uptake by native colonic tissue. Although no changes in total cellular SMVT protein and mRNA levels were observed, LPS caused a decrease in the fraction of SMVT expressed at the cell surface. A role for casein kinase 2 (CK2) (whose activity was also inhibited by LPS) in mediating the endotoxin effects on biotin uptake and on membrane expression of SMVT was suggested by findings that specific inhibitors of CK2, as well as mutating the putative CK2 phosphorylation site (Thr 78 Ala) in the SMVT protein, led to inhibition in biotin uptake and membrane expression of SMVT. This study shows for the first time that LPS inhibits colonic biotin uptake via decreasing membrane expression of its transporter and that these effects likely involve a CK2-mediated pathway.

  8. Artesunate Reduces Serum Lipopolysaccharide in Cecal Ligation/Puncture Mice via Enhanced LPS Internalization by Macrophages through Increased mRNA Expression of Scavenger Receptors

    Directory of Open Access Journals (Sweden)

    Bin Li

    2014-01-01

    Full Text Available Innate immunity is the first line of defense in human beings against pathogen infection; monocytes/macrophages are the primary cells of the innate immune system. Recently, macrophages/monocytes have been discovered to participate in LPS clearance, and the clearance efficiency determines the magnitude of the inflammatory response and subsequent organ injury. Previously, we reported that artesunate (AS protected sepsis mice against heat-killed E. coli challenge. Herein, we further confirmed that AS protected cecal ligation/puncture (CLP sepsis mice. Its protection on sepsis mice was related to not only reduction of pro-inflammatory cytokines and serum LPS levels but also improvement of liver function. Based on the fact that AS did not directly bind and neutralize LPS, we hypothesized that the reduction of serum LPS level might be related to enhancement of LPS internalization and subsequent detoxification. Our results showed that AS increased FITC-LPS internalization by peritoneal macrophage and liver Kupffer cell, but enhancement of LPS internalization by AS was not related to the clathrin-dependent pathway. However, AS induced mRNA expression of important scavenger receptors (SRs; SR-A and MARCO mRNA expression was upregulated, suggesting that AS enhancement of LPS internalization and inhibition of pro-inflammatory cytokines was related to changes in mRNA expression of SRs.

  9. Amomum tsao-ko suppresses lipopolysaccharide-induced inflammatory responses in RAW264.7 macrophages via Nrf2-dependent heme oxygenase-1 expression.

    Science.gov (United States)

    Li, Bin; Choi, Hee-Jin; Lee, Dong-Sung; Oh, Hyuncheol; Kim, Youn-Chul; Moon, Jin-Young; Park, Won-Hwan; Park, Sun-Dong; Kim, Jai-Eun

    2014-01-01

    Amomum tsao-ko Crevost et Lemaire, used as a spice in Asia, is an important source of Chinese cuisine and traditional Chinese medicines. A. tsao-ko is reported to exert a variety of biological and pharmacological activities, including anti-proliferative, anti-oxidative and neuroprotective effects. In this study, NNMBS227, consisting of the ethanol extract of A. tsao-ko, exhibited potent anti-inflammatory activities in RAW264.7 macrophages. We investigated the effect of NNMBS227 in the suppression of pro-inflammatory mediators, including pro-inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) and cytokines (tumor necrosis factor-α and interleukin-1β) in LPS stimulated macrophages. NNMBS227 also inhibited the phosphorylation and degradation of IκB-α, as well as the nuclear translocation of nuclear factor kappa B (NF-κB) p65 caused by stimulation with LPS. In addition, NNMBS227 induced heme oxygenase (HO)-1 expression through the nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) in macrophages. Using tin protoporphyrin (SnPP), an HO activity inhibitor, we confirmed an association between the anti-inflammatory effects of NNMBS227 and the up-regulation of HO-1. These findings suggest that Nrf2-dependent increases in the expression of HO-1 induced by NNMBS227 conferred anti-inflammatory activities in LPS stimulated RAW264.7 macrophages.

  10. Glycyrrhetinic acid attenuates lipopolysaccharide-induced fulminant hepatic failure in D-galactosamine-sensitized mice by up-regulating expression of interleukin-1 receptor-associated kinase-M

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xinru [Department of Pharmacology, Chongqing Medical University, Chongqing 400016 (China); Gong, Xia [Department of Anatomy, Chongqing Medical University, Chongqing 400016 (China); Zhang, Li; Jiang, Rong [Laboratory of Stem Cell and Tissue Engineering, Chongqing Medical University, Chongqing 400016 (China); Kuang, Ge [Department of Pharmacology, Chongqing Medical University, Chongqing 400016 (China); Wang, Bin [Department of Anesthesiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chen, Xinyu [Chongqing Traditional Chinese Medicine Hospital, Chongqing 400021 (China); Wan, Jingyuan, E-mail: jywan@cqmu.edu.cn [Department of Pharmacology, Chongqing Medical University, Chongqing 400016 (China)

    2017-04-01

    Glycyrrhetinic acid (GA), the main active ingredient of licorice, reportedly has anti-inflammatory and hepatoprotective properties, but its molecular mechanisms remain be elusive. In the present study, Balb/c mice were pretreated with GA (10, 30, or 100 mg/kg) 1 h before lipopolysaccharide (LPS)/D-galactosamine (D-GalN) administration. In other in vitro experiment, RAW264.7 macrophages were pretreated with GA before LPS exposure. The mortality, hepatic tissue histology, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed. Toll like receptor 4 (TLR4), interleukin-1 receptor-associated kinases (IRAKs), activation of mitogen-activated protein kinases (MAPKs) and NF-κB, and production of TNF-α were assessed by flow cytometry, western blotting, and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed that pretreatment with GA protected mice against LPS/D-GalN-induced fulminant hepatic failure (FHF), including a dose-dependent alleviation of mortality and ALT/AST elevation, ameliorating hepatic pathological damage, and decreasing TNF-α release. Moreover, GA inhibited LPS-induced activation of MAPKs and NF-κB in response to LPS, but the expression of TLR4 was not affected in vivo and in vitro. Notably, GA pretreatment in vivo suppressed IRAK-1 activity while inducing IRAK-M expression. Silencing of IRAK-M expression with siRNA blocked these beneficial effects of GA on the activation of MAPKs and NF-κB as well as TNF-α production in LPS-primed macrophages. Taken together, we conclude that GA could prevent LPS/D-GalN-induced FHF. The underlying mechanisms may be related to up-regulation of IRAK-M, which in turn caused deactivation of IRAK-1 and subsequent MAPKs and NF-κB, resulting in inhibiting TNF-α production. - Highlights: • Glycyrrhetinic acid protected from LPS/D-GalN-induced liver injury in mice. • Glycyrrhetinic acid inhibited LPS-induced TNF-α production in vivo and in vitro. • Glycyrrhetinic

  11. Oleamide suppresses lipopolysaccharide-induced expression of iNOS and COX-2 through inhibition of NF-kappaB activation in BV2 murine microglial cells.

    Science.gov (United States)

    Oh, Young Taek; Lee, Jung Yeon; Lee, Jinhwa; Lee, Ju Hie; Kim, Ja-Eun; Ha, Joohun; Kang, Insug

    2010-05-03

    Oleamide (cis-9-octadecenamide) is an endogenous sleep-inducing fatty acid amide that accumulates in the cerebrospinal fluid of the sleep-deprived animals. Microglia are the major immune cells involved in neuroinflammation causing brain damage during infection, ischemia, and neurodegenerative disease. In this study, we examined the effects of oleamide on LPS-induced production of proinflammatory mediators and the mechanisms involved in BV2 microglia. Oleamide inhibited LPS-induced production of NO and prostaglandin E2 as well as expression of iNOS and COX-2. We showed that oleamide blocked LPS-induced NF-kappaB activation and phosphorylation of inhibitor kappaB kinase (IKK). We also showed that oleamide inhibited LPS-induced phosphorylation of Akt, p38 MAPK, and ERK, activation of PI 3-kinase, and accumulation of reactive oxygen species (ROS). Finally, we showed that a specific antagonist of the CB2 receptor, AM630, blocked the inhibitory effects of oleamide on LPS-induced production of proinflammatory mediators and activation of NF-kappaB. Taken together, our results suggest that oleamide shows an anti-inflammatory effect through inhibition of NF-kappaB activation in LPS-stimulated BV2 microglia. 2010 Elsevier Ireland Ltd. All rights reserved.

  12. Ketamine inhibits tumor necrosis factor-α and interleukin-6 gene expressions in lipopolysaccharide-stimulated macrophages through suppression of toll-like receptor 4-mediated c-Jun N-terminal kinase phosphorylation and activator protein-1 activation

    International Nuclear Information System (INIS)

    Wu, G.-J.; Chen, T.-L.; Ueng, Y.-F.; Chen, R.-M.

    2008-01-01

    Our previous study showed that ketamine, an intravenous anesthetic agent, has anti-inflammatory effects. In this study, we further evaluated the effects of ketamine on the regulation of tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) gene expressions and its possible signal-transducing mechanisms in lipopolysaccharide (LPS)-activated macrophages. Exposure of macrophages to 1, 10, and 100 μM ketamine, 100 ng/ml LPS, or a combination of ketamine and LPS for 1, 6, and 24 h was not cytotoxic to macrophages. A concentration of 1000 μM of ketamine alone or in combined treatment with LPS caused significant cell death. Administration of LPS increased cellular TNF-α and IL-6 protein levels in concentration- and time-dependent manners. Meanwhile, treatment with ketamine concentration- and time-dependently alleviated the enhanced effects. LPS induced TNF-α and IL-6 mRNA syntheses. Administration of ketamine at a therapeutic concentration (100 μM) significantly inhibited LPS-induced TNF-α and IL-6 mRNA expressions. Application of toll-like receptor 4 (TLR4) small interfering (si)RNA into macrophages decreased cellular TLR4 levels. Co-treatment of macrophages with ketamine and TLR4 siRNA decreased the LPS-induced TNF-α and IL-6 productions more than alone administration of TLR4 siRNA. LPS stimulated phosphorylation of c-Jun N-terminal kinase and translocation of c-Jun and c-Fos from the cytoplasm to nuclei. However, administration of ketamine significantly decreased LPS-induced activation of c-Jun N-terminal kinase and translocation of c-Jun and c-Fos. LPS increased the binding of nuclear extracts to activator protein-1 consensus DNA oligonucleotides. Administration of ketamine significantly ameliorated LPS-induced DNA binding activity of activator protein-1. Therefore, a clinically relevant concentration of ketamine can inhibit TNF-α and IL-6 gene expressions in LPS-activated macrophages. The suppressive mechanisms occur through suppression of TLR4-mediated

  13. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    DEFF Research Database (Denmark)

    Lauridsen, Rikke Kragh; Madsen Sommer, Lea Mette; Johansen, Helle Krogh

    2017-01-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage...... long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children...... were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate...

  14. Effects of Iron on DNA Release and Biofilm Development by Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Barken, Kim Bundvig; Skindersø, Mette Elena

    2007-01-01

    Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum-sensing sy......Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum......-sensing systems has been previously presented. This paper provides evidence that DNA release in P. aeruginosa PAO1 biofilms is also under iron regulation. Experiments involving cultivation of P. aeruginosa in microtitre trays suggested that pqs expression, DNA release and biofilm formation were favoured in media...

  15. Optimization of the expression of phaC2 encoding poly (3-hydroxyalkanoate synthase from Pseudomonas aeruginosa PTCC1310 in Fad B deleted Escherichia coli

    Directory of Open Access Journals (Sweden)

    Daryoush Abedi

    2016-01-01

    Conclusion: We obtained functional expression of the phaC2 gene and investigated various conditions that could influence the expression of protein to optimize production of PHA synthase enzymes. This would allow us to study PHA production in large quantities.

  16. Tasting Pseudomonas aeruginosa biofilms.Human neutrophils express the bitter receptor T2R38 as sensor for the quorum sensing molecule N-(3-oxododecanoyl-L-homoserine lactone

    Directory of Open Access Journals (Sweden)

    Susanne eMaurer

    2015-07-01

    Full Text Available Bacteria communicate with each other via specialized signalling molecules, known as quorum sensing molecules or autoinducers. The Pseudomonas aeruginosa-derived quorum sensing molecule N-(3-oxododecanoyl-L-homoserine lactone (AHL-12, however, also activates mammalian cells. As shown previously, AHL-12 induced chemotaxis, up-regulated CD11b expression, and enhanced phagocytosis of polymorphonuclear neutrophils (PMN. Circumstantial evidence concurred with a receptor for AHL-12, which so far has been elusive. We investigated the bitter receptor T2R38 as a potential candidate. Although identified as a taste receptor, cells outside the gustatory system express T2R38, for example epithelial cells in the lung. We now detected T2R38 in peripheral blood neutrophils, monocytes and lymphocytes on the cell membrane, but also intracellular. In neutrophils, T2R38 was located in vesicles with characteristics of lipid droplets, and super-resolution microscopy showed a co-localisation with the lipid droplet membrane. Neutrophils take up AHL-12, and it co-localized with T2R38 as seen by laser scan microscopy. Binding of AHL-12 to T2R28 was confirmed by pull-down assays using biotin-coupled AHL-12 as bait. A commercially available antibody to T2R38 inhibited binding of AHL-12 to neutrophils, and this antibody by itself stimulated neutrophils, similarly to AHL-12. In conclusion, our data provide evidence for expression of functional T2R38 on neutrophils, and are compatible with the notion that T2R38 is the receptor for AHL-12 on neutrophils.

  17. Pseudomonas aeruginosa cells adapted to benzalkonium chloride show resistance to other membrane-active agents but not to clinically relevant antibiotics.

    Science.gov (United States)

    Loughlin, M F; Jones, M V; Lambert, P A

    2002-04-01

    Our objective was to determine whether strains of Pseudomonas aeruginosa can adapt to growth in increasing concentrations of the disinfectant benzalkonium chloride (BKC), and whether co-resistance to clinically relevant antimicrobial agents occurs. Attempts were made to determine what phenotypic alterations accompanied resistance and whether these explained the mechanism of resistance. Strains were serially passaged in increasing concentrations of BKC in static nutrient broth cultures. Serotyping and genotyping were used to determine purity of the cultures. Two strains were examined for cross-resistance to other disinfectants and antibiotics by broth dilution MIC determination. Alterations in outer membrane proteins and lipopolysaccharide (LPS) expressed were examined by SDS-PAGE. Cell surface hydrophobicity and charge, uptake of disinfectant and proportion of specific fatty acid content of outer and cytoplasmic membranes were determined. Two P. aeruginosa strains showed a stable increase in resistance to BKC. Co-resistance to other quaternary ammonium compounds was observed in both strains; chloramphenicol and polymyxin B resistance were observed in one and a reduction in resistance to tobramycin observed in the other. However, no increased resistance to other biocides (chlorhexidine, triclosan, thymol) or antibiotics (ceftazidime, imipenem, ciprofloxacin, tobramycin) was detected. Characteristics accompanying resistance included alterations in outer membrane proteins, uptake of BKC, cell surface charge and hydrophobicity, and fatty acid content of the cytoplasmic membrane, although no evidence was found for alterations in LPS. Each of the two strains had different alterations in phenotype, indicating that such adaptation is unique to each strain of P. aeruginosa and does not result from a single mechanism shared by the whole species.

  18. Survey of innate immune responses to Burkholderia pseudomallei in human blood identifies a central role for lipopolysaccharide.

    Directory of Open Access Journals (Sweden)

    Narisara Chantratita

    . pseudomallei lipopolysaccharide in blood is greater than the response to other lipopolysaccharide expressing isolates. Our findings suggest that B. pseudomallei lipopolysaccharide may play a central role in stimulating the host response in melioidosis.

  19. Cooperative pathogenicity in cystic fibrosis: Stenotrophomonas maltophilia modulates Pseudomonas aeruginosa virulence in mixed biofilm

    Directory of Open Access Journals (Sweden)

    Arianna ePompilio

    2015-09-01

    Full Text Available The present study was undertaken in order to understand more about the interaction occurring between S. maltophilia and P. aeruginosa, which are frequently co-isolated from CF airways. For this purpose, S. maltophilia RR7 and P. aeruginosa RR8 strains, co-isolated from the lung of a chronically infected CF patient during a pulmonary exacerbation episode, were evaluated for reciprocal effect during planktonic growth, adhesion and biofilm formation onto both polystyrene and CF bronchial cell monolayer, motility, as well as for gene expression in mixed biofilms. P. aeruginosa significantly affected S. maltophilia growth in both planktonic and biofilm cultures, due to an inhibitory activity probably requiring direct contact. Conversely, no effect was observed on P. aeruginosa by S. maltophilia. Compared with monocultures, the adhesiveness of P. aeruginosa on CFBE41o- cells was significantly reduced by S. maltophilia, which probably acts by reducing P. aeruginosa's swimming motility. An opposite trend was observed for biofilm formation, confirming the findings obtained using polystyrene. When grown in mixed biofilm with S. maltophilia, P. aeruginosa significantly over-expressed aprA, and algD - codifying for protease and alginate, respectively - while the quorum sensing related rhlR and lasI genes were down-regulated. The induced alginate expression by P. aeruginosa might be responsible for the protection of S. maltophilia against tobramycin activity we observed in mixed biofilms. Taken together, our results suggest that the existence of reciprocal interference of S. maltophilia and P. aeruginosa in CF lung is plausible. In particular, S. maltophilia might confer some selective fitness advantage to P. aeruginosa under the specific conditions of chronic infection or, alternatively, increase the virulence of P. aeruginosa thus leading to pulmonary exacerbation.

  20. Why Does the Healthy Cornea Resist Pseudomonas aeruginosa Infection?

    Science.gov (United States)

    Evans, David J.; Fleiszig, Suzanne M. J.

    2013-01-01

    Purpose To provide our perspective on why the cornea is resistant to infection based on our research results with Pseudomonas aeruginosa. Perspective We focus on our current understanding of the interplay between bacteria, tear fluid and the corneal epithelium that determine health as the usual outcome, and propose a theoretical model for how contact lens wear might change those interactions to enable susceptibility to P. aeruginosa infection. Methods Use of “null-infection” in vivo models, cultured human corneal epithelial cells, contact lens-wearing animal models, and bacterial genetics help to elucidate mechanisms by which P. aeruginosa survive at the ocular surface, adheres, and traverses multilayered corneal epithelia. These models also help elucidate the molecular mechanisms of corneal epithelial innate defense. Results and Discussion Tear fluid and the corneal epithelium combine to make a formidable defense against P. aeruginosa infection of the cornea. Part of that defense involves the expression of antimicrobials such as β-defensins, the cathelicidin LL-37, cytokeratin-derived antimicrobial peptides, and RNase7. Immunomodulators such as SP-D and ST2 also contribute. Innate defenses of the cornea depend in part on MyD88, a key adaptor protein of TLR and IL-1R signaling, but the basal lamina represents the final barrier to bacterial penetration. Overcoming these defenses involves P. aeruginosa adaptation, expression of the type three secretion system, proteases, and P. aeruginosa biofilm formation on contact lenses. Conclusion After more than two decades of research focused on understanding how contact lens wear predisposes to P. aeruginosa infection, our working hypothesis places blame for microbial keratitis on bacterial adaptation to ocular surface defenses, combined with changes to the biochemistry of the corneal surface caused by trapping bacteria and tear fluid against the cornea under the lens. PMID:23601656

  1. Inhibitory effects of sanguinarine against the cyanobacterium Microcystis aeruginosa NIES-843 and possible mechanisms of action

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Jihai [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Liu, Deming [State Key Laboratory Breeding Base of Crop Germplasm Innovation and Resource Utilization, Hunan Agricultural University, Changsha 410128 (China); Gong, Daoxin; Zeng, Qingru; Yan, Zhiyong [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Gu, Ji-Dong, E-mail: jdgu@hku.hk [Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR (China)

    2013-10-15

    Highlights: •Sanguinarine was found as a strong algicidal biologically derived substance. •Sanguinarine can induce oxidative stress in the cells of Microcystis aeruginosa. •Photosystem is a target of toxicity of sanguinarine on M. aeruginosa. •Sanguinarine can induce DNA damage and inhibit cell division. -- Abstract: Sanguinarine showed strong inhibitory effect against Microcystis aeruginosa, a typical water bloom-forming and microcystins-producing cyanobacterium. The EC50 of sanguinarine against the growth of M. aeruginosa NIES-843 was 34.54 ± 1.17 μg/L. Results of chlorophyll fluorescence transient analysis indicated that all the electron donating side, accepting side, and the reaction center of the Photosystem II (PS II) were the targets of sanguinarine against M. aeruginosa NIES-843. The elevation of reactive oxygen species (ROS) level in the cells of M. aeruginosa NIES-843 upon exposure indicated that sanguinarine induced oxidative stress in the active growing cells of M. aeruginosa NIES-843. Further results of gene expression analysis indicated that DNA damage and cell division inhibition were also involved in the inhibitory action mechanism of sanguinarine against M. aeruginosa NIES-843. The inhibitory characteristics of sanguinarine against M. aeruginosa suggest that the ecological- and public health-risks need to be evaluated before its application in cyanobacterial bloom control to avoid devastating events irreversibly.

  2. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display...... a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because...... the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

  3. The Pseudomonas aeruginosa quorum sensing signal molecule N-(3-oxododecanoyl) homoserine lactone enhances keratinocyte migration and induces Mmp13 gene expression in vitro

    International Nuclear Information System (INIS)

    Paes, Camila; Nakagami, Gojiro; Minematsu, Takeo; Nagase, Takashi; Huang, Lijuan; Sari, Yunita; Sanada, Hiromi

    2012-01-01

    Highlights: ► An evidence of the positive effect of AHL on epithelialization process is provided. ► AHL enhances keratinocyte’s ability to migrate in an in vitro scratch wound model. ► AHL induces the expression of Mmp13. ► Topical application of AHL represents a possible strategy to treat chronic wounds. -- Abstract: Re-epithelialization is an essential step of wound healing involving three overlapping keratinocyte functions: migration, proliferation and differentiation. While quorum sensing (QS) is a cell density-dependent signaling system that enables bacteria to regulate the expression of certain genes, the QS molecule N-(3-oxododecanoyl) homoserine lactone (AHL) exerts effects also on mammalian cells in a process called inter-kingdom signaling. Recent studies have shown that AHL improves epithelialization in in vivo wound healing models but detailed understanding of the molecular and cellular mechanisms are needed. The present study focused on the AHL as a candidate reagent to improve wound healing through direct modulation of keratinocyte’s activity in the re-epithelialization process. Results indicated that AHL enhances the keratinocyte’s ability to migrate in an in vitro scratch wound healing model probably due to the high Mmp13 gene expression analysis after AHL treatment that was revealed by real-time RT-PCR. Inhibition of activator protein 1 (AP-1) signaling pathway completely prevented the migration of keratinocytes, and also resulted in a diminished Mmp13 gene expression, suggesting that AP-1 might be essential in the AHL-induced migration. Taken together, these results imply that AHL is a promising candidate molecule to improve re-epithelialization through the induction of migration of keratinocytes. Further investigation is needed to clarify the mechanism of action and molecular pathway of AHL on the keratinocyte migration process.

  4. The Pseudomonas aeruginosa quorum sensing signal molecule N-(3-oxododecanoyl) homoserine lactone enhances keratinocyte migration and induces Mmp13 gene expression in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Paes, Camila, E-mail: camilaquinetti@gmail.com [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nakagami, Gojiro, E-mail: gojiron-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Minematsu, Takeo, E-mail: tminematsu-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nagase, Takashi, E-mail: tnagase@fb3.so-net.ne.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Huang, Lijuan, E-mail: koureikenhlj@gmail.com [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sari, Yunita, E-mail: yunita-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sanada, Hiromi, E-mail: hsanada-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer An evidence of the positive effect of AHL on epithelialization process is provided. Black-Right-Pointing-Pointer AHL enhances keratinocyte's ability to migrate in an in vitro scratch wound model. Black-Right-Pointing-Pointer AHL induces the expression of Mmp13. Black-Right-Pointing-Pointer Topical application of AHL represents a possible strategy to treat chronic wounds. -- Abstract: Re-epithelialization is an essential step of wound healing involving three overlapping keratinocyte functions: migration, proliferation and differentiation. While quorum sensing (QS) is a cell density-dependent signaling system that enables bacteria to regulate the expression of certain genes, the QS molecule N-(3-oxododecanoyl) homoserine lactone (AHL) exerts effects also on mammalian cells in a process called inter-kingdom signaling. Recent studies have shown that AHL improves epithelialization in in vivo wound healing models but detailed understanding of the molecular and cellular mechanisms are needed. The present study focused on the AHL as a candidate reagent to improve wound healing through direct modulation of keratinocyte's activity in the re-epithelialization process. Results indicated that AHL enhances the keratinocyte's ability to migrate in an in vitro scratch wound healing model probably due to the high Mmp13 gene expression analysis after AHL treatment that was revealed by real-time RT-PCR. Inhibition of activator protein 1 (AP-1) signaling pathway completely prevented the migration of keratinocytes, and also resulted in a diminished Mmp13 gene expression, suggesting that AP-1 might be essential in the AHL-induced migration. Taken together, these results imply that AHL is a promising candidate molecule to improve re-epithelialization through the induction of migration of keratinocytes. Further investigation is needed to clarify the mechanism of action and molecular pathway of AHL on the keratinocyte migration

  5. SIRT2 ameliorates lipopolysaccharide-induced inflammation in macrophages

    International Nuclear Information System (INIS)

    Lee, Ae Sin; Jung, Yu Jin; Kim, Dal; Nguyen-Thanh, Tung; Kang, Kyung Pyo; Lee, Sik; Park, Sung Kwang; Kim, Won

    2014-01-01

    Highlights: • Knockout of SIRT2 attenuates lipopolysaccharide-induced iNOS expression. • Lipopolysaccharide-induced NO production is decreased in SIRT2 KO macrophage. • SIRT2 deficiency suppresses lipopolysaccharide-induced ROS production in macrophage. • M1-macrophage related factors are decreased in SIRT2 deficient cells. • SIRT2 deficiency decreases lipopolysaccharide-induced activation of NFκB. - Abstract: Introduction: SIRT2 is a NAD(+)-dependent deacetylases and associated with numerous processes such as infection, carcinogenesis, DNA damage and cell cycle regulation. However, the role of SIRT2 in inflammatory process in macrophage remains unclear. Materials and methods: In the present study, we have evaluated the regulatory effects of SIRT2 in lipopolysaccharide (LPS)-stimulated macrophages isolated from SIRT2 knockout (KO) and wild type (WT) mice or Raw264.7 macrophage cells. As inflammatory parameters, expression of inducible nitric oxide synthase (iNOS), the productions of nitric oxide, reactive oxygen species (ROS) and M1-macrophage-related factors were evaluated. We also examined the effects of SIRT2 on activation of nuclear factor-kappaB (NFκB) signaling. Results: SIRT2 deficiency inhibits LPS-induced iNOS mRNA and protein expression in bone marrow derived macrophages. SIRT2-siRNA transfection also suppressed LPS-induced iNOS expression in Raw264.7 macrophage cells. Bone marrow derived macrophages isolated from SIRT2 KO mice produced lower nitric oxide and expressed lower levels of M1-macrophage related markers including iNOS and CD86 in response to LPS than WT mice. Decrease of SIRT2 reduced the LPS-induced reactive oxygen species production. Deficiency of SIRT2 resulted in inhibition of NFκB activation through reducing the phosphorylation and degradation of IκBα. The phosphorylation and nuclear translocation of p65 was significantly decreased in SIRT2-deficient macrophages after LPS stimulation. Discussion: Our data suggested that

  6. SIRT2 ameliorates lipopolysaccharide-induced inflammation in macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ae Sin; Jung, Yu Jin; Kim, Dal; Nguyen-Thanh, Tung [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Kang, Kyung Pyo [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Research Institute of Clinical Medicine of Chonbuk National University, Chonbuk National University Hospital, Jeonju (Korea, Republic of); Lee, Sik [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Park, Sung Kwang [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Research Institute of Clinical Medicine of Chonbuk National University, Chonbuk National University Hospital, Jeonju (Korea, Republic of); Kim, Won, E-mail: kwon@jbnu.ac.kr [Department of Internal Medicine, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Research Institute of Clinical Medicine of Chonbuk National University, Chonbuk National University Hospital, Jeonju (Korea, Republic of)

    2014-08-08

    Highlights: • Knockout of SIRT2 attenuates lipopolysaccharide-induced iNOS expression. • Lipopolysaccharide-induced NO production is decreased in SIRT2 KO macrophage. • SIRT2 deficiency suppresses lipopolysaccharide-induced ROS production in macrophage. • M1-macrophage related factors are decreased in SIRT2 deficient cells. • SIRT2 deficiency decreases lipopolysaccharide-induced activation of NFκB. - Abstract: Introduction: SIRT2 is a NAD(+)-dependent deacetylases and associated with numerous processes such as infection, carcinogenesis, DNA damage and cell cycle regulation. However, the role of SIRT2 in inflammatory process in macrophage remains unclear. Materials and methods: In the present study, we have evaluated the regulatory effects of SIRT2 in lipopolysaccharide (LPS)-stimulated macrophages isolated from SIRT2 knockout (KO) and wild type (WT) mice or Raw264.7 macrophage cells. As inflammatory parameters, expression of inducible nitric oxide synthase (iNOS), the productions of nitric oxide, reactive oxygen species (ROS) and M1-macrophage-related factors were evaluated. We also examined the effects of SIRT2 on activation of nuclear factor-kappaB (NFκB) signaling. Results: SIRT2 deficiency inhibits LPS-induced iNOS mRNA and protein expression in bone marrow derived macrophages. SIRT2-siRNA transfection also suppressed LPS-induced iNOS expression in Raw264.7 macrophage cells. Bone marrow derived macrophages isolated from SIRT2 KO mice produced lower nitric oxide and expressed lower levels of M1-macrophage related markers including iNOS and CD86 in response to LPS than WT mice. Decrease of SIRT2 reduced the LPS-induced reactive oxygen species production. Deficiency of SIRT2 resulted in inhibition of NFκB activation through reducing the phosphorylation and degradation of IκBα. The phosphorylation and nuclear translocation of p65 was significantly decreased in SIRT2-deficient macrophages after LPS stimulation. Discussion: Our data suggested that

  7. Fatty acid cosubstrates provide β-oxidation precursors for rhamnolipid biosynthesis in Pseudomonas aeruginosa, as evidenced by isotope tracing and gene expression assays.

    Science.gov (United States)

    Zhang, Lin; Veres-Schalnat, Tracey A; Somogyi, Arpad; Pemberton, Jeanne E; Maier, Raina M

    2012-12-01

    Rhamnolipids have multiple potential applications as "green" surfactants for industry, remediation, and medicine. As a result, they have been intensively investigated to add to our understanding of their biosynthesis and improve yields. Several studies have noted that the addition of a fatty acid cosubstrate increases rhamnolipid yields, but a metabolic explanation has not been offered, partly because biosynthesis studies to date have used sugar or sugar derivatives as the carbon source. The objective of this study was to investigate the role of fatty acid cosubstrates in improving rhamnolipid biosynthesis. A combination of stable isotope tracing and gene expression assays was used to identify lipid precursors and potential lipid metabolic pathways used in rhamnolipid synthesis when fatty acid cosubstrates are present. To this end, we compared the rhamnolipids produced and their yields using either glucose alone or glucose and octadecanoic acid-d(35) as cosubstrates. Using a combination of sugar and fatty acids, the rhamnolipid yield was significantly higher (i.e., doubled) than when glucose was used alone. Two patterns of deuterium incorporation (either 1 or 15 deuterium atoms) in a single Rha-C(10) lipid chain were observed for octadecanoic acid-d(35) treatment, indicating that in the presence of a fatty acid cosubstrate, both de novo fatty acid synthesis and β-oxidation are used to provide lipid precursors for rhamnolipids. Gene expression assays showed a 200- to 600-fold increase in the expression of rhlA and rhlB rhamnolipid biosynthesis genes and a more modest increase of 3- to 4-fold of the fadA β-oxidation pathway gene when octadecanoic acid was present. Taken together, these results suggest that the simultaneous use of de novo fatty acid synthesis and β-oxidation pathways allows for higher production of lipid precursors, resulting in increased rhamnolipid yields.

  8. Antinociceptive principle from Curcuma aeruginosa

    OpenAIRE

    Hossain, Chowdhury Faiz; Al-Amin, Mohammad; Sayem, Abu Sadat Md.; Siragee, Ismail Hossain; Tunan, Asif Mahmud; Hassan, Fahima; Kabir, Md. Mohiuddin; Sultana, Gazi Nurun Nahar

    2015-01-01

    Background The rhizome of Curcuma aeruginosa Roxb (Zingiberaceae) has been used as a traditional folk medicine for the treatment of rheumatic disorders in Bangladesh. The aim of the current study was the bioassay-guided isolation and purification of an antinociceptive principle from the methanol extract of C. aeruginosa rhizomes. Methods The antinociceptive activity was determined using acetic acid induced writhing and formalin induced licking in the Swiss albino mice to investigate central a...

  9. The anti-Pseudomonas aeruginosa antibody Panobacumab is efficacious on acute pneumonia in neutropenic mice and has additive effects with meropenem.

    Directory of Open Access Journals (Sweden)

    Thomas Secher

    Full Text Available Pseudomonas aeruginosa (P. aeruginosa infections are associated with considerable morbidity and mortality in immunocompromised patients due to antibiotic resistance. Therefore, we investigated the efficacy of the anti-P. aeruginosa serotype O11 lipopolysaccharide monoclonal antibody Panobacumab in a clinically relevant murine model of neutropenia induced by cyclophosphamide and in combination with meropenem in susceptible and meropenem resistant P. aeruginosa induced pneumonia. We observed that P. aeruginosa induced pneumonia was dramatically increased in neutropenic mice compared to immunocompetent mice. First, Panobacumab significantly reduced lung inflammation and enhanced bacterial clearance from the lung of neutropenic host. Secondly, combination of Panobacumab and meropenem had an additive effect. Third, Panobacumab retained activity on a meropenem resistant P. aeruginosa strain. In conclusion, the present data established that Panobacumab contributes to the clearance of P. aeruginosa in neutropenic hosts as well as in combination with antibiotics in immunocompetent hosts. This suggests beneficial effects of co-treatment even in immunocompromised individuals, suffering most of the morbidity and mortality of P. aeruginosa infections.

  10. A Bacteriophage-Acquired O-Antigen Polymerase (Wzyβ) from P. aeruginosa Serotype O16 Performs a Varied Mechanism Compared to Its Cognate Wzyα

    DEFF Research Database (Denmark)

    Taylor, Veronique L.; Hoage, Jesse F. J.; Thrane, Sandra Wingaard

    2016-01-01

    Pseudomonas aeruginosa is a Gram-negative bacterium that produces highly varied lipopolysaccharide (LPS) structures. The O antigen (O-Ag) in the LPS is synthesized through the Wzx/Wzy-dependent pathway where lipid-linked O-Ag repeats are polymerized by Wzy. Horizontal-gene transfer has been assoc...

  11. Capsule production by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, A.R.

    1984-01-01

    Mucoid strains of Pseudomonas aeruginosa, associated almost exclusively with chronic respiratory infections in patients with cystic fibrosis, possess a capsule composed of alginic acid similar to one produced by Azotobacter vinelandii. Recent reports have provided evidence that the biosynthetic pathway for alginate in P. aeruginosa may differ from the pathway proposed for A. vinelandii in that synthesis in P. aeruginosa may occur by way of the Entner-Doudoroff pathway. Incorporation of isotope from (6-/sup 14/C)glucose into alginate by both P. aueroginosa and A. vinelandii was 10-fold greater than that from either (1-/sup 14/C)/sup -/ or (2-/sup 14/C)glucose, indicating preferential utilization of the bottom half of the glucose molecule for alginate biosynthesis. These data strongly suggest that the Entner-Doudoroff pathway plays a major role in alginate synthesis in both P. aeruginosa and A. vinelandii. The enzymes of carbohydrate metabolism in mucoid strains of P. aeruginosa appear to be unchanged whether alignate is actively produced or not and activities do not differ significantly from nonmucoid strain PAO.

  12. Current therapies for pseudomonas aeruginosa.

    Science.gov (United States)

    Giamarellou, Helen; Kanellakopoulou, Kyriaki

    2008-04-01

    Based on the worldwide prevalence of multidrug-resistant strains of Pseudomas aeruginosa and the fact that no newer antipseudomonal agents are available, this article aims to investigate therapeutic solutions for combating infections caused by P aeruginosa, including multidrug-resistant strains. The article focuses mainly on colistin, the re-emerging old antibiotic that possesses prominent antipseudomonal activity in vitro and on doripenem, a newer carbapenem that seems to be close to its global marketing. Regarding older antipseudomonal antibiotics that have been reviewed extensively, only newer aspects on their use are considered in this article.

  13. Modulation of immune response by bacterial lipopolysaccharides

    Directory of Open Access Journals (Sweden)

    Gustavo Aldapa-Vega

    2016-08-01

    Full Text Available Lipopolysaccharide (LPS is a molecule that is profusely found on the outer membrane of Gram-negative bacteria and is also a potent stimulator of the immune response. As the main molecule on the bacterial surface, is also the most biologically active. The immune response of the host is activated by the recognition of LPS through Toll-like receptor 4 (TLR4 and this receptor-ligand interaction is closely linked to LPS structure. Microorganisms have evolved systems to control the expression and structure of LPS, producing structural variants that are used for modulating the host immune responses during infection. Examples of this include Helicobacter pylori, Francisella tularensis, Chlamydia trachomatis and Salmonella spp. High concentrations of LPS can cause fever, increased heart rate and lead to septic shock and death. However, at relatively low concentrations some LPS are highly active immunomodulators, which can induce non-specific resistance to invading microorganisms. The elucidation of the molecular and cellular mechanisms involved in the recognition of LPS and its structural variants has been fundamental to understand inflammation and is currently a pivotal field of research to understand the innate immune response, inflammation, the complex host-pathogen relationship and has important implications for the rational development of new immunomodulators and adjuvants.

  14. Attenuation of Neuroinflammatory Responses in Lipopolysaccharide ...

    African Journals Online (AJOL)

    Chenopodiaceae) extract on neuroinflammatory responses induced by lipopolysaccharide (LPS) in BV-2 microglial cells and its antioxidant effects. Methods: Biochemical studies carried out include 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyl-tetrazolium ...

  15. Okra (Abelmoschus esculentus Linn) inhibits lipopolysaccharide ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research June 2017; 16 (6): 1285-1292 ... lipopolysaccharide-induced inflammatory mediators in .... Multiple comparison of data was carried out by one-way. ANOVA followed by Bonferroni post-tests. P <.

  16. Effects of quorum sensing system lasR/rhlR gene on the expression of Foxp3, TGF-β1 and IL-10 of lung tissue in tracheal intubation model rat with Pseudomonas aeruginosa biofilm infection

    Directory of Open Access Journals (Sweden)

    Qing-qing XIANG

    2016-03-01

    Full Text Available Objective  To investigate the effects of lasR/rhlR gene on Foxp3, TGF-β1 and IL-10 of lung tissue in rat tracheal intubation model with biofilm infection of Pseudomonas aeruginosa (Ps. aer wild strain (PAO1 and quorum sensing (QS deficient strain (ΔlasRΔrhlR. Methods  Twenty-one SD rats were randomly assigned into 3 groups (7 each: ΔlasRΔrhlR-treated group, PAO1-treated group and sterile control group. Biofilms (BF were cultured in vitro, and the BF coated tube (infected respectively with Ps. aer PAO1 strain, ΔlasRΔrhlR strain, or with asepsis was inserted into the trachea to establish the rat model. The rats were sacrificed on the 7th day after intubation. Colony count of lung tissue homogenate (cfu and lung HE staining were performed, and IL-10 content in bronchoalveolar lavage fluid (BALF, TGF-β1 in lung tissue, and the expression of Foxp3 mRNA in lung cells were determined. Results  The bacterial counts were significantly higher in PAO1 and ΔlasRΔrhlR groups than that in sterile control group, and the counts were obviously higher in PAO1 group (10 400.00±6313.70/g lung tissue than that in ΔlasRΔrhlR group (975.00±559.97/g lung tissue, P<0.05. There was no significant pathological changes in lung tissue in sterile control group, while the bronchi and blood vessels in PAO1 group were infiltrated by a large number of inflammatory cells and complicated with alveolar septum thickening and local abscess and necrosis. The pathological changes were milder in ΔlasRΔrhlR group than in PAO1 group; the expression of Foxp3 mRNA was higher in the two Ps. aer infected groups than that in sterile control group (0.65±0.32, and it was significantly higher in PAO1 group (4.62±1.07 than in ΔlasRΔrhlR group (2.15±1.43, P<0.05. The accumulated optical density value of TGF-β1 was significantly higher in the two Ps. aer infected groups than in sterile control group (3721.66±1412.95, and significantly higher in PAO1 group (65 090.56±33

  17. Virus-Induced Type I Interferon Deteriorates Control of Systemic Pseudomonas Aeruginosa Infection

    Directory of Open Access Journals (Sweden)

    Katja Merches

    2015-07-01

    Full Text Available Background: Type I interferon (IFN-I predisposes to bacterial superinfections, an important problem during viral infection or treatment with interferon-alpha (IFN-α. IFN-I-induced neutropenia is one reason for the impaired bacterial control; however there is evidence that more frequent bacterial infections during IFN-α-treatment occur independently of neutropenia. Methods: We analyzed in a mouse model, whether Pseudomonas aeruginosa control is influenced by co-infection with the lymphocytic choriomeningitis virus (LCMV. Bacterial titers, numbers of neutrophils and the gene-expression of liver-lysozyme-2 were determined during a 24 hours systemic infection with P. aeruginosa in wild-type and Ifnar-/- mice under the influence of LCMV or poly(I:C. Results: Virus-induced IFN-I impaired the control of Pseudomonas aeruginosa. This was associated with neutropenia and loss of lysozyme-2-expression in the liver, which had captured P. aeruginosa. A lower release of IFN-I by poly(I:C-injection also impaired the bacterial control in the liver and reduced the expression of liver-lysozyme-2. Low concentration of IFN-I after infection with a virulent strain of P. aeruginosa alone impaired the bacterial control and reduced lysozyme-2-expression in the liver as well. Conclusion: We found that during systemic infection with P. aeruginosa Kupffer cells quickly controlled the bacteria in cooperation with neutrophils. Upon LCMV-infection this cooperation was disturbed.

  18. Pycnogenol Attenuates the Release of Proinflammatory Cytokines and Expression of Perilipin 2 in Lipopolysaccharide-Stimulated Microglia in Part via Inhibition of NF-κB and AP-1 Activation.

    Directory of Open Access Journals (Sweden)

    Bin Fan

    Full Text Available Over activation of microglia results in the production of proinflammatory agents that have been implicated in various brain diseases. Pycnogenol is a patented extract from French maritime pine bark (Pinus pinaster Aiton with strong antioxidant and anti-inflammatory potency. The present study investigated whether pycnogenol may be associated with the production of proinflammatory mediators in lipopolysaccharide-stimulated BV2 (mouse-derived microglia. It was found that pycnogenol treatment was dose-dependently associated with significantly less release of nitricoxide (NO, TNF-α, IL-6 and IL-1β, and lower levels of intercellular adhesion molecule1 (ICAM-1 and perilipin 2 (PLIN2. Furthermore, this effect was replicated in primary brain microglia. Levels of inducible NO synthase mRNA and protein were attenuated, whereas there was no change in the production of the anti-inflammatory cytokine IL-10. Further evidence indicated that pycnogenol treatment led to the suppression of NF-κB activation through inhibition of p65 translocation into the nucleus and inhibited DNA binding of AP-1, suggesting that these proinflammatory factors are associated with NF-κB and AP-1. We conclude that pycnogenol exerts anti-inflammatory effects through inhibition of the NF-κB and AP-1pathway, and may be useful as a therapeutic agent in the prevention of diseases caused by over activation of microglia.

  19. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    Science.gov (United States)

    Lauridsen, Rikke Kragh; Sommer, Lea M.; Johansen, Helle Krogh; Rindzevicius, Tomas; Molin, Søren; Jelsbak, Lars; Engelsen, Søren Balling; Boisen, Anja

    2017-03-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm-1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device.

  20. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Werner, E.; Roe, F.; Bugnicourt, A.

    2004-01-01

    In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... synthesis was restricted to a narrow band in the part of the biofilm adjacent to the source of oxygen. The zone of active GFP expression was approximately 60 Am wide in colony biofilms and 30 Am wide in flow cell biofilms. The region of the biofilm in which cells were capable of elongation was mapped...... by treating colony biofilms with carbenicillin, which blocks cell division, and then measuring individual cell lengths by transmission electron microscopy. Cell elongation was localized at the air interface of the biofilm. The heterogeneous anabolic patterns measured inside these biofilms were likely a result...

  1. The isolation and characterization of lipopolysaccharides from Microcystis aeruginosa, a prominent toxic water bloom forming cyanobacteria

    Czech Academy of Sciences Publication Activity Database

    Blahová, L.; Adamovský, O.; Kubala, Lukáš; Šindlerová, Lenka; Zounková, R.; Blaha, L.

    2013-01-01

    Roč. 76, DEC (2013), s. 187-196 ISSN 0041-0101 Grant - others:GA ČR(CZ) GP13-27695P Institutional support: RVO:68081707 Keywords : CYLINDROSPERMOPSIS-RACIBORSKII * ESCHERICHIA-COLI * DANIO - RERIO Subject RIV: BO - Biophysics Impact factor: 2.581, year: 2013

  2. Lipopolysaccharide Binding Protein Enables Intestinal Epithelial Restitution Despite Lipopolysaccharide Exposure

    Science.gov (United States)

    Richter, Juli M.; Schanbacher, Brandon L.; Huang, Hong; Xue, Jianjing; Bauer, John A.; Giannone, Peter J.

    2011-01-01

    Intestinal epithelial restitution is the first part in the process of mucosal repair after injury in the intestine. Integrity of the intestinal mucosal barrier is important as a first line of defense against bacteria and endotoxin. Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in extremely low birth weight infants, but its mechanisms are not well defined. Abnormal bacterial colonization, immature barrier function, innate immunity activation and inflammation likely play a role. Lipopolysaccharide (LPS) binding protein (LBP) is secreted by enterocytes in response to inflammatory stimuli and has concentration-dependent effects. At basal concentrations, LBP stimulates the inflammatory response by presenting LPS to its receptor. However, at high concentrations, LBP is able to neutralize LPS and prevent an exaggerated inflammatory response. We sought to determine how LBP would affect wound healing in an in vitro model of intestinal cell restitution and protect against intestinal injury in a rodent model of NEC. Immature intestinal epithelial cells (IEC-6) were seeded in poly-l-lysine coated 8 chamber slides and grown to confluence. A 500μm wound was created using a cell scraper mounted on the microscope to achieve uniform wounding. Media was replaced with media containing LPS +/− LBP. Slide wells were imaged after 0, 8, and 24 hours and then fixed. Cellular restitution was evaluated via digital images captured on an inverted microscope and wound closure was determined by automated analysis. TLR4 was determined by rtPCR after RNA isolation from wounded cells 24 hours after treatment. LPS alone attenuated wound healing in immature intestinal epithelium. This attenuation is reversed by 24 hours with increasing concentrations of LBP so that wound healing is equivalent to control (p< 0.001). TLR4 was increased with LPS alone but levels returned to that of control after addition of LBP in the higher concentrations. LBP had no effect on the

  3. Lipopolysaccharide (LPS) stimulation of fungal secondary metabolism

    Science.gov (United States)

    Khalil, Zeinab G.; Kalansuriya, Pabasara; Capon, Robert J.

    2014-01-01

    We report on a preliminary investigation of the use the Gram-negative bacterial cell wall constituent lipopolysaccharide (LPS) as a natural chemical cue to stimulate and alter the expression of fungal secondary metabolism. Integrated high-throughput micro-cultivation and micro-analysis methods determined that 6 of 40 (15%) of fungi tested responded to an optimal exposure to LPS (0.6 ng/mL) by activating, enhancing or accelerating secondary metabolite production. To explore the possible mechanisms behind this effect, we employed light and fluorescent microscopy in conjunction with a nitric oxide (NO)-sensitive fluorescent dye and an NO scavenger to provide evidence that LPS stimulation of fungal secondary metabolism coincided with LPS activation of NO. Several case studies demonstrated that LPS stimulation can be scaled from single microplate well (1.5 mL) to preparative (>400 mL) scale cultures. For example, LPS treatment of Penicillium sp. (ACM-4616) enhanced pseurotin A and activated pseurotin A1 and pseurotin A2 biosynthesis, whereas LPS treatment of Aspergillus sp. (CMB-M81F) substantially accelerated and enhanced the biosynthesis of shornephine A and a series of biosynthetically related ardeemins and activated production of neoasterriquinone. As an indication of broader potential, we provide evidence that cultures of Penicillium sp. (CMB-TF0411), Aspergillus niger (ACM-4993F), Rhizopus oryzae (ACM-165F) and Thanatephorus cucumeris (ACM-194F) were responsive to LPS stimulation, the latter two examples being particular noteworthy as neither are known to produce secondary metabolites. Our results encourage the view that LPS stimulation can be used as a valuable tool to expand the molecular discovery potential of fungal strains that either have been exhaustively studied by or are unresponsive to traditional culture methodology. PMID:25379339

  4. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  5. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

    biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...... mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes...

  6. Pseudomonas aeruginosa Population Structure Revisited

    Science.gov (United States)

    Pirnay, Jean-Paul; Bilocq, Florence; Pot, Bruno; Cornelis, Pierre; Zizi, Martin; Van Eldere, Johan; Deschaght, Pieter; Vaneechoutte, Mario; Jennes, Serge; Pitt, Tyrone; De Vos, Daniel

    2009-01-01

    At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among cystic fibrosis (CF) patients and the spread and persistence of multidrug resistant (MDR) strains in hospital wards with high antibiotic pressure, remain contentious. To further investigate the population structure of P. aeruginosa, eight parameters were analyzed and combined for 328 unrelated isolates, collected over the last 125 years from 69 localities in 30 countries on five continents, from diverse clinical (human and animal) and environmental habitats. The analysed parameters were: i) O serotype, ii) Fluorescent Amplified-Fragment Length Polymorphism (FALFP) pattern, nucleotide sequences of outer membrane protein genes, iii) oprI, iv) oprL, v) oprD, vi) pyoverdine receptor gene profile (fpvA type and fpvB prevalence), and prevalence of vii) exoenzyme genes exoS and exoU and viii) group I pilin glycosyltransferase gene tfpO. These traits were combined and analysed using biological data analysis software and visualized in the form of a minimum spanning tree (MST). We revealed a network of relationships between all analyzed parameters and non-congruence between experiments. At the same time we observed several conserved clones, characterized by an almost identical data set. These observations confirm the nonclonal epidemic population structure of P. aeruginosa, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise. One of these clones is the renown and widespread MDR serotype O12 clone. On the other hand, we found no evidence for a widespread CF transmissible clone. All but one of the 43 analysed CF strains belonged to a ubiquitous P

  7. Early events of lethal action by tobramycin in Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Raulston, J.E.

    1988-01-01

    The immediate activities of the aminoglycoside antibiotic, tobramycin, were investigated in Pseudomonas aeruginosa PAO1. The influence of carbon growth substate and the antibiotic exposure environment in the magnitude of activity were examined. Lethality by 8 μg/ml tobramycin occurred rapidly (1 to 3 minutes). The release of specific cellular components into the supernatant was associated with lethality. This material was initially detected as an increase in UV-absorbance. Magnesium in the reaction mixture provided protection against lethality and leakage, but did not reverse lethal damage after a 3 minute tobramycin treatment. Also, uptake of 3 H-tobramycin was reduced in the presence of magnesium. Cells grown with glucose as a carbon source were more susceptible than organic acid grown cells as was the rapidity and amount of cell damage. Analyses of the leakage material revealed a 2-fold increase of protein in the supernatant after a 1-3 minute treatment which paralleled lethality. A prominent 29 kDa protein was observed by SDS-PAGE in the released material, which has been identified as the periplasmic enzyme, β-lactamase. The immediate activities of tobramycin did not involve (i) release of overall cell protein, (ii) massive loss of total pool amino acids, (iii) cell lysis, (iv) inhibition of proline uptake, (v) release of lipopolysaccharide, or (vi) leakage of ATP. Electron microscopy showed no apparent damage after a 3 minute exposure. 40% inhibition of protein synthesis had occurred by 3 minutes of exposure, while release of UV-absorbing material and lethality were detectable after only 1 minute. Resistant cystic fibrosis isolates of P. aeruginosa did not leak under the same experimental conditions, but one of two susceptible strains examined did show increased UV-absorbance following treatment

  8. Pseudomonas aeruginosa infection alters the macrophage phenotype switching process during wound healing in diabetic mice.

    Science.gov (United States)

    Chen, Sinuo; Li, Renren; Cheng, Chun; Xu, Jing-Ying; Jin, Caixia; Gao, Furong; Wang, Juan; Zhang, Jieping; Zhang, Jingfa; Wang, Hong; Lu, Lixia; Xu, Guo-Tong; Tian, Haibin

    2018-03-07

    Macrophages play critical roles in wound healing process. They switch from "classically activated" (M1) phenotype in the early inflammatory phase to "alternatively activated" (M2) phenotype in the later healing phase. However, the dynamic process of macrophage phenotype switching in diabetic wounds burdened with bacteria is unclear. In this report, Pseudomonas aeruginosa, frequently detected in diabetic foot ulcers, was inoculated into cutaneous wounds of db/db diabetic mice to mimic bacterium-infected diabetic wound healing. We observed that P. aeruginosa infection impaired diabetic wound healing and quickly promoted the expression of pro-inflammatory genes (M1 macrophage markers) tumor necrosis factor-α (tnf-α), interleukin-1β (il-1β) and il-6 in wounds. The expression of markers of M2 macrophages, including il-10, arginase-1, and ym1 were also upregulated. In addition, similar gene expression patterns were observed in macrophages isolated directly from wounds. Immunostaining showed that P. aeruginosa infection increased both the ratios of M1 and M2 macrophages in wounds compared with that in control groups, which was further confirmed by in vitro culturing macrophages with P. aeruginosa and skin fibroblast conditioned medium. However, the ratios of the expression levels of pro-inflammatory genes to anti-inflammatory gene il-10 was increased markedly in P. aeruginosa infected wounds and macrophages compared with that in control groups, and P. aeruginosa prolonged the presence of M1 macrophages in the wounds. These data demonstrated that P. aeruginosa in diabetic wounds activates a mixed M1/M2 macrophage phenotype with an excessive activation of M1 phenotype or relatively inadequate activation of M2 phenotype. © 2018 International Federation for Cell Biology.

  9. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

    Science.gov (United States)

    Pazos, Michael A; Lanter, Bernard B; Yonker, Lael M; Eaton, Alex D; Pirzai, Waheed; Gronert, Karsten; Bonventre, Joseph V; Hurley, Bryan P

    2017-08-01

    Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

  10. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

    Directory of Open Access Journals (Sweden)

    Michael A Pazos

    2017-08-01

    Full Text Available Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3, initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4. We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2 activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

  11. Characterization of a lipopolysaccharide mutant of Leptospira derived by growth in the presence of an anti-lipopolysaccharide monoclonal antibody

    NARCIS (Netherlands)

    Zapata, Sonia; Trueba, Gabriel; Bulach, Dieter M.; Boucher, David; Adler, Ben; Hartskeerl, Rudy

    2010-01-01

    A lipopolysaccharide mutant of Leptospira interrogans (LaiMut) was obtained by growth in the presence of an agglutinating monoclonal antibody (mAb) against lipopolysaccharide. Agglutination reactions with anti-lipopolysaccharide mAbs and polyclonal antibodies showed that LaiMut had lost some

  12. Garcinia kola extract reduced lipopolysaccharide activation of ...

    African Journals Online (AJOL)

    The effect of Garcinia kola heckel seed extract on the promonocytic cell line U937 activated by lipopolysaccharide (LPS) was investigated. 200 l of U937 cells maintained in culture at 5 x 105 cells per ml was delivered into wells of a culture plate according to groups. Cells were pre-treated with 20 l of 100 ng/ml phorbol ...

  13. Detection of N-acylhomoserine lactones in lung tissues of mice infected with Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Wu, H; Song, Z; Hentzer, Morten

    2000-01-01

    The pathogenesis of Pseudomonas aeruginosa is associated with expression of virulence factors, many of which are controlled by two N:-acylhomoserine lactone (AHL)-based quorum-sensing systems. Escherichia coli strains equipped with a luxR-based monitor system expressing green fluorescent protein ...

  14. High Glucose and Lipopolysaccharide Prime NLRP3 Inflammasome via ROS/TXNIP Pathway in Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Hong Feng

    2016-01-01

    Full Text Available While inflammation is considered a central component in the development in diabetic nephropathy, the mechanism remains unclear. The NLRP3 inflammasome acts as both a sensor and a regulator of the inflammatory response. The NLRP3 inflammasome responds to exogenous and endogenous danger signals, resulting in cleavage of procaspase-1 and activation of cytokines IL-1β, IL-18, and IL-33, ultimately triggering an inflammatory cascade reaction. This study observed the expression of NLRP3 inflammasome signaling stimulated by high glucose, lipopolysaccharide, and reactive oxygen species (ROS inhibitor N-acetyl-L-cysteine in glomerular mesangial cells, aiming to elucidate the mechanism by which the NLRP3 inflammasome signaling pathway may contribute to diabetic nephropathy. We found that the expression of thioredoxin-interacting protein (TXNIP, NLRP3, and IL-1β was observed by immunohistochemistry in vivo. Simultaneously, the mRNA and protein levels of TXNIP, NLRP3, procaspase-1, and IL-1β were significantly induced by high glucose concentration and lipopolysaccharide in a dose-dependent and time-dependent manner in vitro. This induction by both high glucose and lipopolysaccharide was significantly inhibited by N-acetyl-L-cysteine. Our results firstly reveal that high glucose and lipopolysaccharide activate ROS/TXNIP/ NLRP3/IL-1β inflammasome signaling in glomerular mesangial cells, suggesting a mechanism by which inflammation may contribute to the development of diabetic nephropathy.

  15. Drosophila melanogaster as an animal model for the study of Pseudomonas aeruginosa biofilm infections in vivo.

    Directory of Open Access Journals (Sweden)

    Heidi Mulcahy

    2011-10-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen capable of causing both acute and chronic infections in susceptible hosts. Chronic P. aeruginosa infections are thought to be caused by bacterial biofilms. Biofilms are highly structured, multicellular, microbial communities encased in an extracellular matrix that enable long-term survival in the host. The aim of this research was to develop an animal model that would allow an in vivo study of P. aeruginosa biofilm infections in a Drosophila melanogaster host. At 24 h post oral infection of Drosophila, P. aeruginosa biofilms localized to and were visualized in dissected Drosophila crops. These biofilms had a characteristic aggregate structure and an extracellular matrix composed of DNA and exopolysaccharide. P. aeruginosa cells recovered from in vivo grown biofilms had increased antibiotic resistance relative to planktonically grown cells. In vivo, biofilm formation was dependent on expression of the pel exopolysaccharide genes, as a pelB::lux mutant failed to form biofilms. The pelB::lux mutant was significantly more virulent than PAO1, while a hyperbiofilm strain (PAZHI3 demonstrated significantly less virulence than PAO1, as indicated by survival of infected flies at day 14 postinfection. Biofilm formation, by strains PAO1 and PAZHI3, in the crop was associated with induction of diptericin, cecropin A1 and drosomycin antimicrobial peptide gene expression 24 h postinfection. In contrast, infection with the non-biofilm forming strain pelB::lux resulted in decreased AMP gene expression in the fly. In summary, these results provide novel insights into host-pathogen interactions during P. aeruginosa oral infection of Drosophila and highlight the use of Drosophila as an infection model that permits the study of P. aeruginosa biofilms in vivo.

  16. Pouring Salt on a Wound: Pseudomonas aeruginosa Virulence Factors Alter Na+ and Cl− Flux in the Lung

    Science.gov (United States)

    Ballok, Alicia E.

    2013-01-01

    Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with multiple niches in the human body, including the lung. P. aeruginosa infections are particularly damaging or fatal for patients with ventilator-associated pneumonia, chronic obstructive pulmonary disease, and cystic fibrosis (CF). To establish an infection, P. aeruginosa relies on a suite of virulence factors, including lipopolysaccharide, phospholipases, exoproteases, phenazines, outer membrane vesicles, type III secreted effectors, flagella, and pili. These factors not only damage the epithelial cell lining but also induce changes in cell physiology and function such as cell shape, membrane permeability, and protein synthesis. While such virulence factors are important in initial infection, many become dysregulated or nonfunctional during the course of chronic infection. Recent work on the virulence factors alkaline protease (AprA) and CF transmembrane conductance regulator inhibitory factor (Cif) show that P. aeruginosa also perturbs epithelial ion transport and osmosis, which may be important for the long-term survival of this microbe in the lung. Here we discuss the literature regarding host physiology-altering virulence factors with a focus on Cif and AprA and their potential roles in chronic infection and immune evasion. PMID:23836869

  17. Interactions between Microcystis aeruginosa and coexisting amoxicillin contaminant at different phosphorus levels.

    Science.gov (United States)

    Liu, Ying; Chen, Shi; Chen, Xiao; Zhang, Jian; Gao, Baoyu

    2015-10-30

    Microcystis aeruginosa was cultured with 0.05-5 mg L(-1) of phosphorus and exposed to 200-500 ng L(-1) of amoxicillin for seven days. Amoxicillin presented no significant effect (p>0.05) on the growth of M. aeruginosa at phosphorus levels of 0.05 and 0.2 mg L(-1), but stimulated algal growth as a hormesis effect at phosphorus levels of 1 and 5 mg L(-1). Phosphorus and amoxicillin affected the contents of chlorophyll-a, adenosine triphosphate (ATP) and malondialdehyde, the expression of psbA and rbcL, as well as the activities of adenosinetriphosphatase and glutathione S-transferase in similar manners, but regulated the production and release of microcystins and the activities of superoxide dismutase and peroxidase in different ways. Increased photosynthesis activity was related with the ATP consumption for the stress response to amoxicillin, and the stress response was enhanced as the phosphorus concentration increased. The biodegradation of amoxicillin by M. aeruginosa increased from 11.5% to 28.2% as the phosphorus concentration increased. Coexisting amoxicillin aggravated M. aeruginosa pollution by increasing cell density and concentration of microcystins, while M. aeruginosa alleviated amoxicillin pollution via biodegradation. The interactions between M. aeruginosa and amoxicillin were significantly regulated by phosphorus (p<0.05) and led to a complicated situation of combined pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Sulforaphane Inhibits Lipopolysaccharide-Induced Inflammation, Cytotoxicity, Oxidative Stress, and miR-155 Expression and Switches to Mox Phenotype through Activating Extracellular Signal-Regulated Kinase 1/2-Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Pathway in Murine Microglial Cells.

    Science.gov (United States)

    Eren, Erden; Tufekci, Kemal Ugur; Isci, Kamer Burak; Tastan, Bora; Genc, Kursad; Genc, Sermin

    2018-01-01

    Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the mechanisms of its effects on lipopolysaccharide (LPS)-induced cell death, inflammation, oxidative stress, and polarization in murine microglia. We found that SFN protects N9 microglial cells upon LPS-induced cell death and suppresses LPS-induced levels of secreted pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. SFN is also a potent inducer of redox sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), which is responsible for the transcription of antioxidant, cytoprotective, and anti-inflammatory genes. SFN induced translocation of Nrf2 to the nucleus via extracellular signal-regulated kinase 1/2 (ERK1/2) pathway activation. siRNA-mediated knockdown study showed that the effects of SFN on LPS-induced reactive oxygen species, reactive nitrogen species, and pro-inflammatory cytokine production and cell death are partly Nrf2 dependent. Mox phenotype is a novel microglial phenotype that has roles in oxidative stress responses. Our results suggested that SFN induced the Mox phenotype in murine microglia through Nrf2 pathway. SFN also alleviated LPS-induced expression of inflammatory microRNA, miR-155. Finally, SFN inhibits microglia-mediated neurotoxicity as demonstrated by conditioned medium and co-culture experiments. In conclusion, SFN exerts protective effects on microglia and modulates the microglial activation state.

  19. Placental-mediated increased cytokine response to lipopolysaccharides: a potential mechanism for enhanced inflammation susceptibility of the preterm fetus

    Directory of Open Access Journals (Sweden)

    Ross MG

    2012-07-01

    Full Text Available Julie L Boles,1 Michael G Ross,1 Ron Beloosesky,2 Mina Desai,1 Louiza Belkacemi11Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute at Harbor-UCLA, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Torrance, CA, USA; 2Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, IsraelBackground: Cerebral palsy is a nonprogressive motor impairment syndrome that has no effective cure. The etiology of most cases of cerebral palsy remains unknown; however, recent epidemiologic data have demonstrated an association between fetal neurologic injury and infection/inflammation. Maternal infection/inflammation may be associated with the induction of placental cytokines that could result in increased fetal proinflammatory cytokine exposure, and development of neonatal neurologic injury. Therefore, we sought to explore the mechanism by which maternal infection may produce a placental inflammatory response. We specifically examined rat placental cytokine production and activation of the Toll-like receptor 4 (TLR4 pathway in response to lipopolysaccharide exposure at preterm and near-term gestational ages.Methods: Preterm (e16 or near-term (e20 placental explants from pregnant rats were treated with 0, 1, or 10 µg/mL lipopolysaccharide. Explant integrity was assessed by lactate dehydrogenase assay. Interleukin-6 and tumor necrosis alpha levels were determined using enzyme-linked immunosorbent assay kits. TLR4 and phosphorylated nuclear factor kappa light chain enhancer of activated B cells (NFκB protein expression levels were determined by Western blot analysis.Results: At both e16 and e20, lactate dehydrogenase levels were unchanged by treatment with lipopolysaccharide. After exposure to lipopolysaccharide, the release of interleukin-6 and tumor necrosis alpha from e16 placental explants increased by 4-fold and 8–9-fold, respectively (P < 0.05 versus

  20. Regulation and function of versatile aerobic and anaerobic respiratory metabolism in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hiroyuki eArai

    2011-05-01

    Full Text Available Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO, and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article.

  1. Within-host evolution of Pseudomonas aeruginosa reveals adaptation toward iron acquisition from hemoglobin

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Pedersen, Søren Damkiær; Khademi, Seyed Mohammad Hossein

    2014-01-01

    the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth...... advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive...... might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. IMPORTANCE Most bacterial pathogens depend on scavenging iron within their hosts, which makes the battle for iron between pathogens and hosts a hallmark of infection. Accordingly, the ability...

  2. C-di-GMP regulates antimicrobial peptide resistance in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Chua, Song Lin; Tan, Sean Yang-Yi; Rybtke, Morten Theil

    2013-01-01

    Bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger which controls the life styles of many bacteria. A high intracellular level of c-di-GMP induces a biofilm lifestyle, whereas a low intracellular level of c-di-GMP stimulates dispersal of biofilms and promotes...... a planktonic lifestyle. Here, we used expression of different reporters to show that planktonic cells (PCells), biofilm cells (BCells) and cells dispersed from biofilms (DCells) had distinct intracellular c-di-GMP levels. Proteomics analysis showed that the low intracellular c-di-GMP level of DCells induced...... the expression of proteins required for the virulence and development of antimicrobial peptide resistance in P. aeruginosa. In accordance, P. aeruginosa cells with low c-di-GMP levels were found to be more resistant to colistin than P. aeruginosa cells with high c-di-GMP levels. This contradicts the current...

  3. Benzoxazole derivatives suppress lipopolysaccharide-induced mast cell activation.

    Science.gov (United States)

    Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee; Choo, Hea-Young Park; Lee, Kyung Ho

    2018-05-01

    Mast cells are central regulators of allergic inflammation that function by releasing various proallergic inflammatory mediators, including histamine, eicosanoids and proinflammatory cytokines. Occasionally, bacterial infections may initiate or worsen allergic inflammation. A number of studies have indicated that activation of lipoxygenase in mast cells positive regulates allergic inflammatory responses by generating leukotrienes and proinflammatory cytokines. In the present study, the effects of benzoxazole derivatives on the lipopolysaccharide (LPS)‑induced expression of proinflammatory cytokines, production of histamine and surface expression of co‑stimulatory molecules on bone marrow-derived mast cells (BMMCs) were studied. The benzoxazole derivatives significantly reduced the expression of interleukin (IL)‑1β, IL‑6, IL‑13, tumor necrosis factor‑α, perilipin (PLIN) 2, and PLIN3 in BMMCs treated with LPS. Furthermore, histamine production was suppressed in BMMCs treated with LPS, or treated with phorbol-12-myristate-13-acetate/ionomycin. Benzoxazole derivatives marginally affected the surface expression of cluster of differentiation (CD)80 and CD86 on BMMCs in the presence of LPS, although LPS alone did not increase the expression of those proteins. Therefore, benzoxazole derivatives inhibited the secretion of proinflammatory cytokines in mast cells and may be potential candidate anti‑allergic agents to suppress mast cell activation.

  4. Lipopolysaccharide-induced acute renal failure in conscious rats

    DEFF Research Database (Denmark)

    Jonassen, Thomas E N; Graebe, Martin; Promeneur, Dominique

    2002-01-01

    In conscious, chronically instrumented rats we examined 1) renal tubular functional changes involved in lipopolysaccharide (LPS)-induced acute renal failure; 2) the effects of LPS on the expression of selected renal tubular water and sodium transporters; and 3) effects of milrinone......-alpha and lactate, inhibited the LPS-induced tachycardia, and exacerbated the acute LPS-induced fall in GFR. Furthermore, Ro-20-1724-treated rats were unable to maintain MAP. We conclude 1) PDE3 or PDE4 inhibition exacerbates LPS-induced renal failure in conscious rats; and 2) LPS treated rats develop an escape......, a phosphodiesterase type 3 (PDE3) inhibitor, and Ro-20-1724, a PDE4 inhibitor, on LPS-induced changes in renal function. Intravenous infusion of LPS (4 mg/kg b.wt. over 1 h) caused an immediate decrease in glomerular filtration rate (GFR) and proximal tubular outflow without changes in mean arterial pressure (MAP...

  5. Adenosine A1, A2a, A2B, and A3 receptors in hematopoiesis. 2. Expression of receptor mRNA in resting and lipopolysaccharide-activated mouse RAW 264.7 macrophages

    Czech Academy of Sciences Publication Activity Database

    Štreitová, Denisa; Hofer, Michal; Holá, Jiřina; Vacek, Antonín; Pospíšil, Milan

    2010-01-01

    Roč. 59, č. 1 (2010), s. 139-144 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA305/06/0015; GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : adenosine receptors * macrophage * mRNA expression Subject RIV: BO - Biophysics Impact factor: 1.646, year: 2010

  6. Blastogenic response of bovine lymphocytes to Brucella abortus lipopolysaccharide.

    OpenAIRE

    Baldwin, C L; Winter, A J

    1985-01-01

    Brucella abortus lipopolysaccharide was tested in a blastogenesis assay with unfractionated and nylon wool-separated peripheral blood lymphocytes of Brucella-naive cattle and cattle immunized with B. abortus. Our results indicated that in cattle the lipopolysaccharide of B. abortus is not a B-cell mitogen. In immunized animals it stimulated predominantly nylon wool-adherent cells. The lipopolysaccharide of Escherichia coli O128:B12, in contrast, induced a substantially greater proliferative r...

  7. Interleukin-10 Protection against Lipopolysaccharide-Induced Neuro-Inflammation and Neurotoxicity in Ventral Mesencephalic Cultures

    OpenAIRE

    Yan Zhu; Xiao Chen; Zhan Liu; Yu-Ping Peng; Yi-Hua Qiu

    2015-01-01

    Interleukin (IL)-10, an anti-inflammatory cytokine, is expressed in the brain and can inhibit microglial activation. Herein, we utilized lipopolysaccharide (LPS)-induced inflammatory Parkinson?s disease (PD) cell model to determine whether microglia and astrocytes are necessary targets for IL-10 neuroprotection. Primary ventral mesencephalic (VM) cultures with different composition of neurons, microglia and astrocytes were prepared. The cells were exposed to IL-10 (15, 50 or 150 ng/mL) 1 h pr...

  8. Pseudomonas aeruginosa (Family Pseudomonadaceae) is an ...

    African Journals Online (AJOL)

    Pseudomonas aeruginosa (Family Pseudomonadaceae) is an obligate aerobic, motile, gram negative bacillus.which is able to grow and survive in almost any environment and resistant to temperature extremes. It is involved in the etiology of several diseases i.

  9. Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    ABSTRACT: This work investigated the prevalence and antibiotics sensitivity of Pseudomonas aeruginosa isolated from ... skin triggers coagulation and an acute inflammatory response ... agents with anti-pseudomonal activity, life-threatening.

  10. Effect of new disinfectant substances on pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Majtan, V.

    1998-01-01

    The anti-bacterial effect of 13 new commercially manufactured disinfectant substances on P. aeruginosa strain was studied. The substances tested represent 9 quaternary ammonium salts QAT and 4 combined QAT with other ingredients. The antimicrobial efficacy was characterised by influencing the growth and reproduction of bacterial cells expressed either by MIC and ED 50 as well as and ED 50 , as well as by the inhibition of incorporation rate of incorporation rate of [ 14 C] adenine and [ 14 C] leucine. The method of inhibition of [ 14 C] precursors is suitable as one from possible evaluation criterion on anti-bacterial efficacy of synthetic disinfectant substances. (authors)

  11. A Mig-14-like protein (PA5003) affects antimicrobial peptide recognition in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jochumsen, Nicholas; Liu, Yang; Molin, Søren

    2011-01-01

    The evolution of antibiotic resistance in pathogenic bacteria is a growing global health problem which is gradually making the treatment of infectious diseases less efficient. Antimicrobial peptides are small charged molecules found in organisms from the complete phylogenetic spectrum. The peptides...... are attractive candidates for novel drug development due to their activity against bacteria that are resistant to conventional antibiotics, and reports of peptide resistance are rare in the clinical setting. Paradoxically, many clinically relevant bacteria have mechanisms that can recognize and respond...... to the presence of cationic antimicrobial peptides (CAMPs) in the environment by changing the properties of the microbial surface thereby increasing the tolerance of the microbes towards the peptides. In Pseudomonas aeruginosa an essential component of this inducible tolerance mechanism is the lipopolysaccharide...

  12. Cytokine gene expression of peripheral blood lymphocytes ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-03-20

    Mar 20, 2009 ... Key words: Lipopolysaccharide, lymphocytes, TLRs, cytokines. INTRODUCTION. Lipopolysaccharide (LPS), a predominant glycolipid in the outer membranes of Gam-negative bacteria, stimulates monocyte, macrophages, and neutrophils and increase expression of cell adhesion molecules (Trent et al., ...

  13. Cloning and Characterization of EF-Tu and EF-Ts from Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Stephanie O. Palmer

    2013-01-01

    Full Text Available We have cloned genes encoding elongation factors EF-Tu and EF-Ts from Pseudomonas aeruginosa and expressed and purified the proteins to greater than 95% homogeneity. Sequence analysis indicated that P. aeruginosa EF-Tu and EF-Ts are 84% and 55% identical to E. coli counterparts, respectively. P. aeruginosa EF-Tu was active when assayed in GDP exchange assays. Kinetic parameters for the interaction of EF-Tu with GDP in the absence of EF-Ts were observed to be = 33 μM, = 0.003 s−1, and the specificity constant was  s−1 μM−1. In the presence of EF-Ts, these values were shifted to = 2 μM, = 0.005 s−1, and the specificity constant was  s−1 μM−1. The equilibrium dissociation constants governing the binding of EF-Tu to GDP ( were 30–75 nM and to GTP ( were 125–200 nM. EF-Ts stimulated the exchange of GDP by EF-Tu 10-fold. P. aeruginosa EF-Tu was active in forming a ternary complex with GTP and aminoacylated tRNA and was functional in poly(U-dependent binding of Phe-tRNAPhe at the A-site of P. aeruginosa ribosomes. P. aeruginosa EF-Tu was active in poly(U-programmed polyphenylalanine protein synthesis system composed of all P. aeruginosa components.

  14. Effect of lipopolysaccharide on sickness behaviour in hens kept in cage and free range environments.

    Science.gov (United States)

    Gregory, N G; Payne, S R; Devine, C D; Cook, C J

    2009-08-01

    The aim of this study was to assess whether environmental enrichment and environmental conditions can influence the expression of sickness behaviour. The behaviour in response to injection of lipopolysaccharide or saline was examined in a total of 96 62-weeks old hatchmate hens kept in a free range or cage environment. There were eight experimental treatments, each with 12 birds. Half the birds were sourced from a commercial cage layer unit (C/-) and half from a commercial free range unit (FR/-). After intraperitoneal injection with either lipopolysaccharide or saline (as a control), the hens were placed in either a cage (-/C) or free range (-/FR) environment. Lipopolysaccharide caused greater suppression of activity in free range (FR/FR) than in caged hens, including less walking (53% reduction), roosting (-86%) and preening (-60%) (pfree range, nor in free range birds introduced to cages, suggesting that both the presence of and the familiarity with an environment affected sickness behaviour patterns. Increased sleeping was the most consistent response (+147%; pfree range layer hens can express a greater range of sickness behaviours than caged hens, and this may make it more difficult to recognise disease expression in the caged environment.

  15. Pseudomonas aeruginosa Trent and zinc homeostasis.

    Science.gov (United States)

    Davies, Corey B; Harrison, Mark D; Huygens, Flavia

    2017-09-01

    Pseudomonas aeruginosa is a Gram-negative pathogen and the major cause of mortality in patients with cystic fibrosis. The mechanisms that P. aeruginosa strains use to regulate intracellular zinc have an effect on infection, antibiotic resistance and the propensity to form biofilms. However, zinc homeostasis in P. aeruginosa strains of variable infectivity has not been compared. In this study, zinc homeostasis in P. aeruginosa Trent, a highly infectious clinical strain, was compared to that of a laboratory P. aeruginosa strain, ATCC27853. Trent was able to tolerate higher concentrations of additional zinc in rich media than ATCC27853. Further, pre-adaptation to additional zinc enhanced the growth of Trent at non-inhibitory concentrations but the impact of pre-adaption on the growth of ATCC27853 under the same conditions was minimal. The results establish clear differences in zinc-induced responses in Trent and ATCC27853, and how zinc homeostasis can be a promising target for the development of novel antimicrobial strategies for P. aeruginosa infection in cystic fibrosis patients. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K.; Hentzer, Morten; Geisenberger, O.

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co- ordinate expression of virulence factors with the form...

  17. Pyoverdine and PQS Mediated Subpopulation Interactions Involved in Pseudomonas aeruginosa Biofilm Formation

    DEFF Research Database (Denmark)

    Yang, Liang; Nilsson, Martin; Gjermansen, Morten

    2009-01-01

    Using flow chamber-grown Pseudomonas aeruginosa biofilms as model system, we show in the present study that formation of heterogeneous biofilms may occur through mechanisms that involve complex subpopulation interactions. One example of this phenomenon is expression of the iron...

  18. Role of quorum sensing by Pseudomonas aeruginosa in microbial keratitis and cystic fibrosis

    DEFF Research Database (Denmark)

    Willcox, M.D.P.; Zhu, H.; Conibear, T.C.R.

    2008-01-01

    to control the expression of many virulence factors is the N-acylated homoserine lactone (AHL) regulatory system. Hence, there is considerable interest in targeting this regulatory pathway to develop novel therapeutics for infection control. P. aeruginosa is the principal cause of microbial keratitis...

  19. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, K.; Rasmussen, Thomas Bovbjerg

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR lay expression of an unstable version of the green-fluorescent protein (Gfp...

  20. DMPD: Structural and functional analyses of bacterial lipopolysaccharides. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 12106784 Structural and functional analyses of bacterial lipopolysaccharides. Carof...html) (.csml) Show Structural and functional analyses of bacterial lipopolysaccharides. PubmedID 12106784 Title Structural and functi...onal analyses of bacterial lipopolysaccharides. Authors

  1. Interleukin-6 production by human monocytes treated with granulocyte-macrophage colony-stimulating factor in the presence of lipopolysaccharide of oral microorganisms.

    Science.gov (United States)

    Baqui, A A; Meiller, T F; Chon, J J; Turng, B F; Falkler, W A

    1998-06-01

    This study focused on the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) and lipopolysaccharide of the putative periodontal pathogens Porphyromonas gingivalis or Fusobacterium nucleatum on IL-6 production by THP-1 cells (a human monocytic cell line). Resting THP-1 cells were alternatively treated with GM-CSF (50 IU/ml) and lipopolysaccharide of P. gingivalis or F. nucleatum, in varying concentrations for varying time periods. IL-6 production in supernatant fluids of treated cells was evaluated by an enzyme-linked immunosorbent assay (ELISA) and a reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate gene expression. Untreated THP-1 cells did not produce IL-6 as determined by ELISA. RT-PCR also failed to detect IL-6 mRNA in untreated THP-1 cells, indicating that IL-6 was not constitutively produced. After stimulation of THP-1 cells with lipopolysaccharide of F. nucleatum or P. gingivalis, IL-6 was produced, peaking at 4 h (200-300 pg/ml) and thereafter sharply declining by 8 h. When GM-CSF was added together with lipopolysaccharide of P. gingivalis or F. nucleatum, there was a synergistic quantitative increase in production of IL-6 as measured by ELISA as compared with lipopolysaccharide alone. IL-6 mRNA was detected by RT-PCR, 15 min after stimulation with lipopolysaccharide of either P. gingivalis or F. nucleatum. GM-CSF supplementation with lipopolysaccharide of P. gingivalis shortened the transcription of IL-6 mRNA to 5 min, a shift which was not observed with lipopolysaccharide of F. nucleatum, possibly indicating a different mechanism of initiation of transcription. Production of IL-6 by GM-CSF-treated THP-1 cells in the presence of lipopolysaccharide of oral microorganisms may provide a model for studying the role of macrophages in acute and chronic periodontal diseases, including the clinical periodontal exacerbation as observed in chemotherapy patients receiving GM-CSF for bone marrow recovery.

  2. Cyanobacterial lipopolysaccharides and human health – a review

    Directory of Open Access Journals (Sweden)

    Schluter Philip J

    2006-03-01

    Full Text Available Abstract Cyanobacterial lipopolysaccharide/s (LPS are frequently cited in the cyanobacteria literature as toxins responsible for a variety of heath effects in humans, from skin rashes to gastrointestinal, respiratory and allergic reactions. The attribution of toxic properties to cyanobacterial LPS dates from the 1970s, when it was thought that lipid A, the toxic moiety of LPS, was structurally and functionally conserved across all Gram-negative bacteria. However, more recent research has shown that this is not the case, and lipid A structures are now known to be very different, expressing properties ranging from LPS agonists, through weak endotoxicity to LPS antagonists. Although cyanobacterial LPS is widely cited as a putative toxin, most of the small number of formal research reports describe cyanobacterial LPS as weakly toxic compared to LPS from the Enterobacteriaceae. We systematically reviewed the literature on cyanobacterial LPS, and also examined the much lager body of literature relating to heterotrophic bacterial LPS and the atypical lipid A structures of some photosynthetic bacteria. While the literature on the biological activity of heterotrophic bacterial LPS is overwhelmingly large and therefore difficult to review for the purposes of exclusion, we were unable to find a convincing body of evidence to suggest that heterotrophic bacterial LPS, in the absence of other virulence factors, is responsible for acute gastrointestinal, dermatological or allergic reactions via natural exposure routes in humans. There is a danger that initial speculation about cyanobacterial LPS may evolve into orthodoxy without basis in research findings. No cyanobacterial lipid A structures have been described and published to date, so a recommendation is made that cyanobacteriologists should not continue to attribute such a diverse range of clinical symptoms to cyanobacterial LPS without research confirmation.

  3. Dexmedetomidine reduces lipopolysaccharide induced neuroinflammation, sickness behavior, and anhedonia.

    Directory of Open Access Journals (Sweden)

    Ching-Hua Yeh

    Full Text Available Peripheral innate immune response may induce sickness behavior through activating microglia, excessive cytokines production, and neuroinflammation. Dexmedetomidine (Dex has anti-inflammatory effect. We investigated the effects of Dex on lipopolysaccharide (LPS-induced neuroinflammation and sickness behavior in mice.BALB/c mice were intraperitoneally (i.p. injected with Dex (50 ug/kg or vehicle. One hour later, the mice were injected (i.p. with Escherichia coli LPS (0.33 mg/kg or saline (n = 6 in each group. We analyzed the food and water intake, body weight loss, and sucrose preference of the mice for 24h. We also determined microglia activation and cytokines expression in the brains of the mice. In vitro, we determine cytokines expression in LPS-treated BV-2 microglial cells with or without Dex treatment.In the Dex-pretreated mice, LPS-induced sickness behavior (anorexia, weight loss, and social withdrawal were attenuated and microglial activation was lower than vehicle control. The mRNA expression of TNF-α, MCP-1, indoleamine 2, 3 dioxygenase (IDO, caspase-3, and iNOS were increased in the brain of LPS-challenged mice, which were reduced by Dex but not vehicle.Dexmedetomidine diminished LPS-induced neuroinflammation in the mouse brain and modulated the cytokine-associated changes in sickness behavior.

  4. Coxiella burnetii Lipopolysaccharide: What Do We Know?

    Science.gov (United States)

    Abnave, Prasad; Muracciole, Xavier; Ghigo, Eric

    2017-01-01

    A small gram-negative bacterium, Coxiella burnetii (C. burnetii), is responsible for a zoonosis called Q fever. C. burnetii is an intracellular bacterium that can survive inside microbicidal cells like monocytes and macrophages by hijacking several functions of the immune system. Among several virulence factors, the lipopolysaccharide (LPS) of C. burnetii is one of the major factors involved in this immune hijacking because of its atypical composition and structure. Thus, the aim of this mini-review is to summarize the repressive effects of C. burnetii LPS on the antibacterial immunity of cells. PMID:29168790

  5. Immunoelectron microscopy of lipopolysaccharide in Chlamydia trachomatis

    DEFF Research Database (Denmark)

    Birkelund, Svend; Lundemose, AG; Christiansen, Gunna

    1989-01-01

    Monoclonal antibodies (MAb) specific for Chlamydia trachomatis lipopolysaccharide (LPS) and major outer membrane protein (MOMP) were used for immunoelectron microscopy analysis. MAb specific for MOMP showed strong reaction with the chlamydial surface, whereas MAb specific for LPS showed strong...... association of gold particles with the periphery of the chlamydial body. After fixation of the chlamydia cells, the reactivity was, however, similar to the anti-MOMP reactivity. Enzyme-linked immunosorbent assay showed that MAb specific for LPS could remove LPS from the chlamydial membrane....

  6. Coxiella burnetii Lipopolysaccharide: What Do We Know?

    Directory of Open Access Journals (Sweden)

    Prasad Abnave

    2017-11-01

    Full Text Available A small gram-negative bacterium, Coxiella burnetii (C. burnetii, is responsible for a zoonosis called Q fever. C. burnetii is an intracellular bacterium that can survive inside microbicidal cells like monocytes and macrophages by hijacking several functions of the immune system. Among several virulence factors, the lipopolysaccharide (LPS of C. burnetii is one of the major factors involved in this immune hijacking because of its atypical composition and structure. Thus, the aim of this mini-review is to summarize the repressive effects of C. burnetii LPS on the antibacterial immunity of cells.

  7. Bacterial lipopolysaccharide promotes profibrotic activation of intestinal fibroblasts.

    LENUS (Irish Health Repository)

    Burke, J P

    2012-02-01

    BACKGROUND: Fibroblasts play a critical role in intestinal wound healing. Lipopolysaccharide (LPS) is a cell wall component of commensal gut bacteria. The effects of LPS on intestinal fibroblast activation were characterized. METHODS: Expression of the LPS receptor, toll-like receptor (TLR) 4, was assessed in cultured primary human intestinal fibroblasts using flow cytometry and confocal microscopy. Fibroblasts were treated with LPS and\\/or transforming growth factor (TGF) beta1. Nuclear factor kappaB (NFkappaB) pathway activation was assessed by inhibitory kappaBalpha (IkappaBalpha) degradation and NFkappaB promoter activity. Fibroblast contractility was measured using a fibroblast-populated collagen lattice. Smad-7, a negative regulator of TGF-beta1 signalling, and connective tissue growth factor (CTGF) expression were assessed using reverse transcriptase-polymerase chain reaction and western blot. The NFkappaB pathway was inhibited by IkappaBalpha transfection. RESULTS: TLR-4 was present on the surface of intestinal fibroblasts. LPS treatment of fibroblasts induced IkappaBalpha degradation, enhanced NFkappaB promoter activity and increased collagen contraction. Pretreatment with LPS (before TGF-beta1) significantly increased CTGF production relative to treatment with TGF-beta1 alone. LPS reduced whereas TGF-beta1 increased smad-7 expression. Transfection with an IkappaBalpha plasmid enhanced basal smad-7 expression. CONCLUSION: Intestinal fibroblasts express TLR-4 and respond to LPS by activating NFkappaB and inducing collagen contraction. LPS acts in concert with TGF-beta1 to induce CTGF. LPS reduces the expression of the TGF-beta1 inhibitor, smad-7.

  8. Major Transcriptome Changes Accompany the Growth of Pseudomonas aeruginosa in Blood from Patients with Severe Thermal Injuries.

    Directory of Open Access Journals (Sweden)

    Cassandra Kruczek

    Full Text Available Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in immunocompromised hosts including severely burned patients. After multiplying within the burn wound, P. aeruginosa translocate into the bloodstream causing bacterial sepsis frequently leading to organ dysfunction and septic shock. Although the pathogenesis of P. aeruginosa infection of thermally-injured wounds has been extensively analyzed, little is known regarding the ability of P. aeruginosa to adapt and survive within the blood of severely burned patients during systemic infection. To identify such adaptations, transcriptome analyses (RNA-seq were conducted on P. aeruginosa strain PA14 that was grown in whole blood from a healthy volunteer or three severely burned patients. Compared with growth in blood from healthy volunteers, growth of PA14 in the blood from severely burned patients significantly altered the expression of 2596 genes, with expression of 1060 genes enhanced, while that of 1536 genes was reduced. Genes whose expression was significantly reduced included genes related to quorum sensing, quorum sensing-controlled virulence factors and transport of heme, phosphate, and phosphonate. Genes whose expression was significantly enhanced were related to the type III secretion system, the pyochelin iron-acquisition system, flagellum synthesis, and pyocyanin production. We confirmed changes in expression of many of these genes using qRT-PCR. Although severe burns altered the levels of different blood components in each patient, the growth of PA14 in their blood produced similar changes in the expression of each gene. These results suggest that, in response to changes in the blood of severely burned patients and as part of its survival strategy, P. aeruginosa enhances the expression of certain virulence genes and reduces the expression of others.

  9. Autogenous regulation and kinetics of induction of Pseudomonas aeruginosa recA transcription as analyzed with operon fusions

    International Nuclear Information System (INIS)

    Horn, J.M.; Ohman, D.E.

    1988-01-01

    A promoterless chloramphenicol acetyltransferase gene (cat) was used to construct recA-cat operon fusions to quantitatively examine the transcriptional regulation of the Pseudomonas aeruginosa recA gene in P. aeruginosa PAO. Wild-type P. aeruginosa containing the recA8-cat fusion was treated with methyl methanesulfonate (MMS) and showed immediate induction of chloramphenicol acetyltransferase (CAT) specific activity, whereas a recA::Tn501 mutant of P. aeruginosa containing recA8-cat showed no induction with MMS. This indicated that a functional copy of recA was required for derepression of recA transcription and that P. aeruginosa recA protein was a positive regulatory factor promoting its own expression. Compared with that in the wild type, the uninduced level of CAT in recA8-cat-containing cells was reduced by approximately one-half in the recA::Tn501 mutant, indicating that recA+-dependent spontaneous induction contributes to the uninduced levels of recA expression in P. aeruginosa. MMS (0.012%) caused recA-directed CAT synthesis to increase almost immediately, with maximum CAT activity, fourfold higher than uninduced levels, attained at 60 min postinduction. The kinetics of recA8-cat fusion activity were shown to be directly related to the MMS doses used. Another fusion called recAa1-cat, where cat was located between the two transcriptional terminators of the P. aeruginosa recA gene, also showed dose-dependent induction by MMS, but the CAT activity from recAa1-cat was only one-half of that obtained with recA8-cat under the same conditions. Treatment of recA+ P. aeruginosa containing recA8-cat with UV irradiation produced an immediate effect on recA8-cat transcription and showed little UV dose dependency at doses of 5 J/m2 or greater

  10. Spatial transcriptomes within the Pseudomonas aeruginosa biofilm architecture.

    Science.gov (United States)

    Heacock-Kang, Yun; Sun, Zhenxin; Zarzycki-Siek, Jan; McMillan, Ian A; Norris, Michael H; Bluhm, Andrew P; Cabanas, Darlene; Fogen, Dawson; Vo, Hung; Donachie, Stuart P; Borlee, Bradley R; Sibley, Christopher D; Lewenza, Shawn; Schurr, Michael J; Schweizer, Herbert P; Hoang, Tung T

    2017-12-01

    Bacterial cooperative associations and dynamics in biofilm microenvironments are of special interest in recent years. Knowledge of localized gene-expression and corresponding bacterial behaviors within the biofilm architecture at a global scale has been limited, due to a lack of robust technology to study limited number of cells in stratified layers of biofilms. With our recent pioneering developments in single bacterial cell transcriptomic analysis technology, we generated herein an unprecedented spatial transcriptome map of the mature in vitro Pseudomonas aeruginosa biofilm model, revealing contemporaneous yet altered bacterial behaviors at different layers within the biofilm architecture (i.e., surface, middle and interior of the biofilm). Many genes encoding unknown functions were highly expressed at the biofilm-solid interphase, exposing a critical gap in the knowledge of their activities that may be unique to this interior niche. Several genes of unknown functions are critical for biofilm formation. The in vivo importance of these unknown proteins was validated in invertebrate (fruit fly) and vertebrate (mouse) models. We envisage the future value of this report to the community, in aiding the further pathophysiological understanding of P. aeruginosa biofilms. Our approach will open doors to the study of bacterial functional genomics of different species in numerous settings. © 2017 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

  11. Comparative genome and transcriptome analysis reveals distinctive surface characteristics and unique physiological potentials of Pseudomonas aeruginosa ATCC 27853

    KAUST Repository

    Cao, Huiluo

    2017-06-12

    Pseudomonas aeruginosa ATCC 27853 was isolated from a hospital blood specimen in 1971 and has been widely used as a model strain to survey antibiotics susceptibilities, biofilm development, and metabolic activities of Pseudomonas spp.. Although four draft genomes of P. aeruginosa ATCC 27853 have been sequenced, the complete genome of this strain is still lacking, hindering a comprehensive understanding of its physiology and functional genome.Here we sequenced and assembled the complete genome of P. aeruginosa ATCC 27853 using the Pacific Biosciences SMRT (PacBio) technology and Illumina sequencing platform. We found that accessory genes of ATCC 27853 including prophages and genomic islands (GIs) mainly contribute to the difference between P. aeruginosa ATCC 27853 and other P. aeruginosa strains. Seven prophages were identified within the genome of P. aeruginosa ATCC 27853. Of the predicted 25 GIs, three contain genes that encode monoxoygenases, dioxygenases and hydrolases that could be involved in the metabolism of aromatic compounds. Surveying virulence-related genes revealed that a series of genes that encode the B-band O-antigen of LPS are lacking in ATCC 27853. Distinctive SNPs in genes of cellular adhesion proteins such as type IV pili and flagella biosynthesis were also observed in this strain. Colony morphology analysis confirmed an enhanced biofilm formation capability of ATCC 27853 on solid agar surface compared to Pseudomonas aeruginosa PAO1. We then performed transcriptome analysis of ATCC 27853 and PAO1 using RNA-seq and compared the expression of orthologous genes to understand the functional genome and the genomic details underlying the distinctive colony morphogenesis. These analyses revealed an increased expression of genes involved in cellular adhesion and biofilm maturation such as type IV pili, exopolysaccharide and electron transport chain components in ATCC 27853 compared with PAO1. In addition, distinctive expression profiles of the

  12. Peripheral tumors alter neuroinflammatory responses to lipopolysaccharide in female rats.

    Science.gov (United States)

    Pyter, Leah M; El Mouatassim Bih, Sarah; Sattar, Husain; Prendergast, Brian J

    2014-03-13

    Cancer is associated with an increased prevalence of depression. Peripheral tumors induce inflammatory cytokine production in the brain and depressive-like behaviors. Mounting evidence indicates that cytokines are part of a pathway by which peripheral inflammation causes depression. Neuroinflammatory responses to immune challenges can be exacerbated (primed) by prior immunological activation associated with aging, early-life infection, and drug exposure. This experiment tested the hypothesis that peripheral tumors likewise induce neuroinflammatory sensitization or priming. Female rats with chemically-induced mammary carcinomas were injected with either saline or lipopolysaccharide (LPS, 250μg/kg; i.p.), and expression of mRNAs involved in the pathway linking inflammation and depression (interleukin-1beta [Il-1β], CD11b, IκBα, indolamine 2,3-deoxygenase [Ido]) was quantified by qPCR in the hippocampus, hypothalamus, and frontal cortex, 4 or 24h post-treatment. In the absence of LPS, hippocampal Il-1β and CD11b mRNA expression were elevated in tumor-bearing rats, whereas Ido expression was reduced. Moreover, in saline-treated rats basal hypothalamic Il-1β and CD11b expression were positively correlated with tumor weight; heavier tumors, in turn, were characterized by more inflammatory, necrotic, and granulation tissue. Tumors exacerbated CNS proinflammatory gene expression in response to LPS: CD11b was greater in hippocampus and frontal cortex of tumor-bearing relative to tumor-free rats, IκBα was greater in hippocampus, and Ido was greater in hypothalamus. Greater neuroinflammatory responses in tumor-bearing rats were accompanied by attenuated body weight gain post-LPS. The data indicate that neuroinflammatory pathways are potentiated, or primed, in tumor-bearing rats, which may exacerbate future negative behavioral consequences. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. The effects of hydrogen peroxide on the circadian rhythms of Microcystis aeruginosa.

    Directory of Open Access Journals (Sweden)

    Haifeng Qian

    Full Text Available BACKGROUND: The cyanobacterium Microcystis aeruginosa is one of the principal bloom-forming cyanobacteria present in a wide range of freshwater ecosystems. M. aeruginosa produces cyanotoxins, which can harm human and animal health. Many metabolic pathways in M. aeruginosa, including photosynthesis and microcystin synthesis, are controlled by its circadian rhythms. However, whether xenobiotics affect the cyanobacterial circadian system and change its growth, physiology and biochemistry is unknown. We used real-time PCR to study the effect of hydrogen peroxide (H(2O(2 on the expression of clock genes and some circadian genes in M. aeruginosa during the light/dark (LD cycle. RESULTS: The results revealed that H(2O(2 changes the expression patterns of clock genes (kaiA, kaiB, kaiC and sasA and significantly decreases the transcript levels of kaiB, kaiC and sasA. H(2O(2 treatment also decreased the transcription of circadian genes, such as photosynthesis-related genes (psaB, psbD1 and rbcL and microcystin-related genes (mcyA, mcyD and mcyH, and changed their circadian expression patterns. Moreover, the physiological functions of M. aeruginosa, including its growth and microcystin synthesis, were greatly influenced by H(2O(2 treatment during LD. These results indicate that changes in the cyanobacterial circadian system can affect its physiological and metabolic pathways. CONCLUSION: Our findings show that a xenobiotic can change the circadian expression patterns of its clock genes to influence clock-controlled gene regulation, and these influences are evident at the level of cellular physiology.

  14. Pseudomonas aeruginosa Dose-Response and Bathing Water Infection

    Science.gov (United States)

    Pseudomonas aeruginosa is the most commonly identified opportunistic pathogen associated with pool acquired bather disease. To better understand why this microorganism poses this protracted problem we recently appraised P. aeruginosa pool risk management. Much is known about the ...

  15. Riboflavin attenuates lipopolysaccharide-induced lung injury in rats.

    Science.gov (United States)

    Al-Harbi, Naif O; Imam, Faisal; Nadeem, Ahmed; Al-Harbi, Mohammed M; Korashy, Hesham M; Sayed-Ahmed, Mohammed M; Hafez, Mohamed M; Al-Shabanah, Othman A; Nagi, Mahmoud N; Bahashwan, Saleh

    2015-01-01

    Riboflavin (vitamin B2) is an easily absorbed micronutrient with a key role in maintaining health in humans and animals. It is the central component of the cofactors flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) and is therefore required by all flavoproteins. Riboflavin also works as an antioxidant by scavenging free radicals. The present study was designed to evaluate the effects of riboflavin against acute lungs injury induced by the administration of a single intranasal dose (20 μg/rat) of lipopolysaccharides (LPS) in experimental rats. Administration of LPS resulted in marked increase in malondialdehyde (MDA) level (p riboflavin in a dose-dependent manner (30 and 100 mg/kg, respectively). Riboflavin (100 mg/kg, p.o.) showed similar protective effects as dexamethasone (1 mg/kg, p.o.). Administration of LPS showed marked cellular changes including interstitial edema, hemorrhage, infiltration of PMNs, etc., which were reversed by riboflavin administration. Histopathological examinations showed normal morphological structures of lungs tissue in the control group. These biochemical and histopathological examination were appended with iNOS and CAT gene expression. The iNOS mRNA expression was increased significantly (p riboflavin significantly (p riboflavin caused a protective effect against LPS-induced ALI. These results suggest that riboflavin may be used to protect against toxic effect of LPS in lungs.

  16. Calcium hydroxide suppresses Porphyromonas endodontalis lipopolysaccharide-induced bone destruction.

    Science.gov (United States)

    Guo, J; Yang, D; Okamura, H; Teramachi, J; Ochiai, K; Qiu, L; Haneji, T

    2014-05-01

    Porphyromonas endodontalis and its main virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical diseases and alveolar bone loss. Calcium hydroxide is commonly used for endodontic therapy. However, the effects of calcium hydroxide on the virulence of P. endodontalis LPS and the mechanism of P. endodontalis LPS-induced bone destruction are not clear. Calcium hydroxide rescued the P. endodontalis LPS-suppressed viability of MC3T3-E1 cells and activity of nuclear factor-κB (NF-κB) in these cells, resulting in the reduced expression of interleukin-6 and tumor necrosis factor-α. In addition, calcium hydroxide inhibited P. endodontalis LPS-induced osteoclastogenesis by decreasing the activities of NF-κB, p38, and ERK1/2 and the expression of nuclear factor of activated T-cell cytoplasmic 1 in RAW264.7 cells. Calcium hydroxide also rescued the P. endodontalis LPS-induced osteoclastogenesis and bone destruction in mouse calvaria. Taken together, our present results indicate that calcium hydroxide suppressed bone destruction by attenuating the virulence of P. endodontalis LPS on bone cells.

  17. Novel Path Towards Colistin Resistance In Pseudomonas Aeruginosa During Chronic Infection Involves Polymorphisms In Uncharacterized Glycosyltransferase Gene

    DEFF Research Database (Denmark)

    Hermansen, Grith Miriam Maigaard; Jelsbak, Lars

    2015-01-01

    Introduction: Antibiotic resistance development in the gram-negative bacterium Pseudomonas aeruginosa is an increasing problem. The effect of colistin, one of the few last resort drugs commonly given to cystic fibrosis (CF) patients, is dependent on the lipopolysaccharide (LPS) structure. We have...... inhibitory concentration by microbroth dilution, virulence in an amoebae model and LPS structure by visualization in a silver-stained gel. Results: Reversion of the SNP to reference genotype resulted in increased colistin susceptibility, reduced virulence in an amoebae model and altered LPS structure...

  18. Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia induce distinct host responses.

    Science.gov (United States)

    McConnell, Kevin W; McDunn, Jonathan E; Clark, Andrew T; Dunne, W Michael; Dixon, David J; Turnbull, Isaiah R; Dipasco, Peter J; Osberghaus, William F; Sherman, Benjamin; Martin, James R; Walter, Michael J; Cobb, J Perren; Buchman, Timothy G; Hotchkiss, Richard S; Coopersmith, Craig M

    2010-01-01

    Pathogens that cause pneumonia may be treated in a targeted fashion by antibiotics, but if this therapy fails, then treatment involves only nonspecific supportive measures, independent of the inciting infection. The purpose of this study was to determine whether host response is similar after disparate infections with similar mortalities. Prospective, randomized controlled study. Animal laboratory in a university medical center. Pneumonia was induced in FVB/N mice by either Streptococcus pneumoniae or two different concentrations of Pseudomonas aeruginosa. Plasma and bronchoalveolar lavage fluid from septic animals was assayed by a microarray immunoassay measuring 18 inflammatory mediators at multiple time points. The host response was dependent on the causative organism as well as kinetics of mortality, but the pro-inflammatory and anti-inflammatory responses were independent of inoculum concentration or degree of bacteremia. Pneumonia caused by different concentrations of the same bacteria, Pseudomonas aeruginosa, also yielded distinct inflammatory responses; however, inflammatory mediator expression did not directly track the severity of infection. For all infections, the host response was compartmentalized, with markedly different concentrations of inflammatory mediators in the systemic circulation and the lungs. Hierarchical clustering analysis resulted in the identification of five distinct clusters of the host response to bacterial infection. Principal components analysis correlated pulmonary macrophage inflammatory peptide-2 and interleukin-10 with progression of infection, whereas elevated plasma tumor necrosis factor sr2 and macrophage chemotactic peptide-1 were indicative of fulminant disease with >90% mortality within 48 hrs. Septic mice have distinct local and systemic responses to Streptococcus pneumoniae and Pseudomonas aeruginosa pneumonia. Targeting specific host inflammatory responses induced by distinct bacterial infections could represent a

  19. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2013-01-01

    Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed.......Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....

  20. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, E T; Kharazmi, A; Garred, P

    1993-01-01

    In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm...... mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed...... immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact...

  1. Aspergillus triggers phenazine production in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jensen, Britt Guillaume; Jelsbak, Lars; Søndergaard, Ib

    in the contact area of A. niger, A. flavus, A. oryzae, but not A. fumigatus. In addition, other metabolites with UV chromophores similar to the phenazines were only found in the contact zone between Aspergillus and Pseudomonas. No change in secondary metabolite profiles were seen for the Aspergilli, when......Objectives: Pseudomonas aeruginosa is an opportunistic human pathogen, commonly infecting cystic fibrosis (CF) patients. Aspergilli, especially Aspergillus fumigatus, are also frequently isolated from CF patients. Our aim was to examine the possible interaction between P. aeruginosa and different...... Aspergillus species. Methods: A suspension of fungal spores was streaked onto WATM agar plates. After 24 hours incubation at 37 °C, a P. aeruginosa overnight culture was streaked out perpendicular to the fungal streak. The plates were incubated at 37 °C for five days, examined and plugs were extracted...

  2. Effects of various forms of lipopolysaccharide on the expression of ...

    African Journals Online (AJOL)

    Jane

    2011-10-05

    Oct 5, 2011 ... Lan-jun Bai1, Wings TY Loo2,3,4*, Yiding Dou4, Min Wang5, Hao Liang5, Mary NB Cheung3,4,6 ... The levels of lactate dehydrogenase (LDH), N-terminal pro ...... Li G-R, Sun H-Y, Chen J-B, Zhou Y, Tse H-F, Lau C-P (2009).

  3. Correlation between antimicrobial consumption and antimicrobial resistance of Pseudomonas aeruginosa in a hospital setting: a 10-year study.

    Science.gov (United States)

    Mladenovic-Antic, S; Kocic, B; Velickovic-Radovanovic, R; Dinic, M; Petrovic, J; Randjelovic, G; Mitic, R

    2016-10-01

    Antimicrobial resistance is one of the greatest threats to human health. One of the most important factors leading to the emergence of resistant bacteria is overuse of antibiotics. The purpose of this study was to investigate the correlation between antimicrobial usage and bacterial resistance of Pseudomonas aeruginosa (P. aeruginosa) over a 10-year period in the Clinical Center Niš, one of the biggest tertiary care hospitals in Serbia. We focused on possible relationships between the consumption of carbapenems and beta-lactam antibiotics and the rates of resistance of P. aeruginosa to carbapenems. We recorded utilization of antibiotics expressed as defined daily doses per 100 bed days (DBD). Bacterial resistance was reported as the percentage of resistant isolates (percentage of all resistant and intermediate resistant strains) among all tested isolates. A significant increasing trend in resistance was seen in imipenem (P resistance to amikacin (P resistance to imipenem in P. aeruginosa shows significance (P resistance to meropenem showed a trend towards significance (P > 0·05, Pearson r = 0·607). We found a very good correlation between the use of all beta-lactam and P. aeruginosa resistance to carbapenems (P antimicrobial resistance to carbapenems, significant correlations between the consumption of antibiotics, especially carbapenems and beta-lactams, and rates of antimicrobial resistance of P. aeruginosa to imipenem and meropenem. © 2016 John Wiley & Sons Ltd.

  4. Application of protein typing in molecular epidemiological investigation of nosocomial infection outbreak of aminoglycoside-resistant Pseudomonas aeruginosa.

    Science.gov (United States)

    Song, Min; Tang, Min; Ding, Yinghuan; Wu, Zecai; Xiang, Chengyu; Yang, Kui; Zhang, Zhang; Li, Baolin; Deng, Zhenghua; Liu, Jinbo

    2017-12-16

    Pseudomonas aeruginosan has emerged as an important pathogen elated to serious infections and nosocomial outbreaks worldwide. This study was conducted to understand the prevalence of aminoglycoside (AMG)-resistant P. aeruginosa in our hospital and to provide a scientific basis for control measures against nosocomial infections. Eighty-two strains of P. aeruginosa were isolated from clinical departments and divided into AMG-resistant strains and AMG-sensitive strains based on susceptibility test results. AMG-resistant strains were typed by drug resistance gene typing (DRGT) and protein typing. Five kinds of aminoglycoside-modifying enzyme (AME) genes were detected in the AMG-resistant group. AMG-resistant P. aeruginosa strains were classified into three types and six subtypes by DRGT. Four protein peaks, namely, 9900.02, 7600.04, 9101.25 and 10,372.87 Da, were significantly and differentially expressed between the two groups. AMG-resistant P. aeruginosa strains were also categorised into three types and six subtypes at the distance level of 10 by protein typing. AMG-resistant P. aeruginosa was cloned spread in our hospital; the timely implementation of nosocomial infection prevention and control strategies were needed in preventing outbreaks and epidemic of AMG-resistant P. aeruginosa. SELDI-TOF MS technology can be used for bacterial typing, which provides a new method of clinical epidemiological survey and nosocomial infection control.

  5. Extracts of Cordia gilletii de wild (Boraginaceae) quench the quorum sensing of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Okusa, Philippe N; Rasamiravaka, Tsiry; Vandeputte, Olivier; Stévigny, Caroline; Jaziri, Mondher El; Duez, Pierre

    2014-01-01

    The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties like disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect on the production of Pseudomonas aeruginosa major virulence factors regulated by QS. The effect of C. gilletii extracts on virulence factors of P. aeruginosa PAO1 was studied by the evaluation of the production of pyocyanine, elastase and biofilm; and by the measurement of the expression of QS-related genes. The dichloromethane extract from root barks was found to quench the production of pyocyanin, a QS-dependent virulence factor in P. aeruginosa PAO1. Moreover, this extract specifically inhibits the expression of several QS-regulated genes (i.e. lasB, rhlA, lasI, lasR, rhlI, and rhlR) and reduces biofilm formation by PAO1. This study contributes to explain the efficacy of C. gilletii in the traditional treatment of infectious diseases caused by P. aeruginosa.

  6. Extracts of Cordia gilletii de wild (Boraginaceae) quench the quorum sensing of Pseudomonas aeruginosa PAO1

    Science.gov (United States)

    Okusa, Philippe N.; Rasamiravaka, Tsiry; Vandeputte, Olivier; Stévigny, Caroline; Jaziri, Mondher El; Duez, Pierre

    2014-01-01

    Aim: The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties like disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect on the production of Pseudomonas aeruginosa major virulence factors regulated by QS. Materials and Methods: The effect of C. gilletii extracts on virulence factors of P. aeruginosa PAO1 was studied by the evaluation of the production of pyocyanine, elastase and biofilm; and by the measurement of the expression of QS-related genes. Results: The dichloromethane extract from root barks was found to quench the production of pyocyanin, a QS-dependent virulence factor in P. aeruginosa PAO1. Moreover, this extract specifically inhibits the expression of several QS-regulated genes (i.e. lasB, rhlA, lasI, lasR, rhlI, and rhlR) and reduces biofilm formation by PAO1. Conclusion: This study contributes to explain the efficacy of C. gilletii in the traditional treatment of infectious diseases caused by P. aeruginosa. PMID:26401363

  7. Pseudomonas aeruginosa induces pigment production and enhances virulence in a white phenotypic variant of Staphylococcus aureus.

    Science.gov (United States)

    Antonic, Vlado; Stojadinovic, Alexander; Zhang, Binxue; Izadjoo, Mina J; Alavi, Mohammad

    2013-01-01

    Staphyloxanthin is a virulence factor which protects Staphylococcus aureus in stress conditions. We isolated two pigment variants of S. aureus and one strain of Pseudomonas aeruginosa from a single wound infection. S. aureus variants displayed white and yellow colony phenotypes. The sequence of the operons for staphyloxanthin synthesis indicated that coding and promoter regions were identical between the two pigment variants. Quorum sensing controls pigment synthesis in some bacteria. It is also shown that P. aeruginosa quorum-sensing molecules affect S. aureus transcription. We explored whether the co-infecting P. aeruginosa can affect pigment production in the white S. aureus variant. In co-culture experiments between the white variants and a selected number of Gram-positive and Gram-negative bacteria, only P. aeruginosa induced pigment production in the white variant. Gene expression analysis of the white variant did not indicate upregulation of the crtM and other genes known to be involved in pigment production (sigB, sarA, farnesyl pyrophosphate synthase gene [FPP-synthase], hfq). In contrast, transcription of the catalase gene was significantly upregulated after co-culture. P. aeruginosa-induced pigment synthesis and catalase upregulation correlated with increased resistance to polymyxin B, hydrogen peroxide, and the intracellular environment of macrophages. Our data indicate the presence of silent but functional staphyloxanthin synthesis machinery in a white phenotypic variant of S. aureus which is activated by a co-infecting P. aeruginosa via inter-species communication. Another S. aureus virulence factor, catalase is also induced by this co-infecting bacterium. The resulting phenotypic changes are directly correlated with resistance of the white variant to stressful conditions.

  8. Sputum Active Polymyxin Lipopeptides: Activity against Cystic Fibrosis Pseudomonas aeruginosa Isolates and Their Interactions with Sputum Biomolecules.

    Science.gov (United States)

    Schneider-Futschik, Elena K; Paulin, Olivia K A; Hoyer, Daniel; Roberts, Kade D; Ziogas, James; Baker, Mark A; Karas, John; Li, Jian; Velkov, Tony

    2018-05-11

    The mucoid biofilm mode of growth of Pseudomonas aeruginosa ( P. aeruginosa) in the lungs of cystic fibrosis patients makes eradication of infections with antibiotic therapy very difficult. The lipopeptide antibiotics polymyxin B and colistin are currently the last-resort therapies for infections caused by multidrug-resistant P. aeruginosa. In the present study, we investigated the antibacterial activity of a series of polymyxin lipopeptides (polymyxin B, colistin, FADDI-003, octapeptin A 3 , and polymyxin A 2 ) against a panel of polymyxin-susceptible and polymyxin-resistant P. aeruginosa cystic fibrosis isolates grown under planktonic or biofilm conditions in artificial sputum and their interactions with sputum component biomolecules. In sputum media under planktonic conditions, the lipopeptides FADDI-003 and octapeptin A 3 displayed very promising activity against the polymyxin-resistant isolate FADDI-PA066 (polymyxin B minimum inhibitory concentration (MIC) = 32 mg/L), while retaining their activity against the polymyxin-sensitive strains FADDI-PA021 (polymyxin B MIC = 1 mg/L) and FADDI-PA020 (polymyxin B MIC = 2 mg/L). Polymyxin A 2 was only effective against the polymyxin-sensitive isolates. However, under biofilm growth conditions, the hydrophobic lipopeptide FADDI-003 was inactive compared to the more hydrophilic lipopeptides, octapeptin A 3 , polymyxin A 2 , polymyxin B, and colistin. Transmission electron micrographs revealed octapeptin A 3 caused reduction in the cell numbers in biofilm as well as biofilm disruption/"antibiofilm" activity. We therefore assessed the interactions of the lipopeptides with the component sputum biomolecules, mucin, deoxyribonucleic acid (DNA), surfactant, F-actin, lipopolysaccharide, and phospholipids. We observed the general trend that sputum biomolecules reduce lipopeptide antibacterial activity. Collectively, our data suggests that, in the airways, lipopeptide binding to component sputum biomolecules may reduce

  9. PAMDB: a comprehensive Pseudomonas aeruginosa metabolome database.

    Science.gov (United States)

    Huang, Weiliang; Brewer, Luke K; Jones, Jace W; Nguyen, Angela T; Marcu, Ana; Wishart, David S; Oglesby-Sherrouse, Amanda G; Kane, Maureen A; Wilks, Angela

    2018-01-04

    The Pseudomonas aeruginosaMetabolome Database (PAMDB, http://pseudomonas.umaryland.edu) is a searchable, richly annotated metabolite database specific to P. aeruginosa. P. aeruginosa is a soil organism and significant opportunistic pathogen that adapts to its environment through a versatile energy metabolism network. Furthermore, P. aeruginosa is a model organism for the study of biofilm formation, quorum sensing, and bioremediation processes, each of which are dependent on unique pathways and metabolites. The PAMDB is modelled on the Escherichia coli (ECMDB), yeast (YMDB) and human (HMDB) metabolome databases and contains >4370 metabolites and 938 pathways with links to over 1260 genes and proteins. The database information was compiled from electronic databases, journal articles and mass spectrometry (MS) metabolomic data obtained in our laboratories. For each metabolite entered, we provide detailed compound descriptions, names and synonyms, structural and physiochemical information, nuclear magnetic resonance (NMR) and MS spectra, enzymes and pathway information, as well as gene and protein sequences. The database allows extensive searching via chemical names, structure and molecular weight, together with gene, protein and pathway relationships. The PAMBD and its future iterations will provide a valuable resource to biologists, natural product chemists and clinicians in identifying active compounds, potential biomarkers and clinical diagnostics. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Regulation of Initial Attachment of P. aeruginosa

    Science.gov (United States)

    2010-12-08

    shown to play a role in promoting biofilm formation in diverse P. aeruginosa strains (Friedman and Kolter , 2004; Jackson et al., 2004; Ryder et al...34House of Biofilm Cells". J. Bacteriol. 189: 7945-7947. Friedman, L., and Kolter , R. (2004) Genes involved in matrix formation in Pseudomonas

  11. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

    As we have extracted pyocyanin both from P. aeruginosa cultures, and via chemical synthesis; we know the procedural and product-quality differences. We endorse the relative ease, safety, and convenience of using the chemical synthesis described here. Crucially, our “naturally endotoxin-free” pyocyanin can be extracted easily without using infectious bacteria.

  12. Pseudomonas aeruginosa AlgR Phosphorylation Status Differentially Regulates Pyocyanin and Pyoverdine Production

    Directory of Open Access Journals (Sweden)

    Alexander S. Little

    2018-01-01

    Full Text Available Pseudomonas aeruginosa employs numerous, complex regulatory elements to control expression of its many virulence systems. The P. aeruginosa AlgZR two-component regulatory system controls the expression of several crucial virulence phenotypes. We recently determined, through transcriptomic profiling of a PAO1 ΔalgR mutant strain compared to wild-type PAO1, that algZR and hemCD are cotranscribed and show differential iron-dependent gene expression. Previous expression profiling was performed in strains without algR and revealed that AlgR acts as either an activator or repressor, depending on the gene. Thus, examination of P. aeruginosa gene expression from cells locked into different AlgR phosphorylation states reveals greater physiological relevance. Therefore, gene expression from strains carrying algR alleles encoding a phosphomimetic (AlgR D54E or a phosphoablative (AlgR D54N form were compared by microarray to PAO1. Transcriptome analyses of these strains revealed 25 differentially expressed genes associated with iron siderophore biosynthesis or heme acquisition or production. The PAO1 algR D54N mutant produced lower levels of pyoverdine but increased expression of the small RNAs prrf1 and prrf2 compared to PAO1. In contrast, the algR D54N mutant produced more pyocyanin than wild-type PAO1. On the other hand, the PAO1 algR D54E mutant produced higher levels of pyoverdine, likely due to increased expression of an iron-regulated gene encoding the sigma factor pvdS, but it had decreased pyocyanin production. AlgR specifically bound to the prrf2 and pvdS promoters in vitro. AlgR-dependent pyoverdine production was additionally influenced by carbon source rather than the extracellular iron concentration per se. AlgR phosphorylation effects were also examined in a Drosophila melanogaster feeding, murine acute pneumonia, and punch wound infection models. Abrogation of AlgR phosphorylation attenuated P. aeruginosa virulence in these infection

  13. Melatonin protects against myocardial hypertrophy induced by lipopolysaccharide.

    Science.gov (United States)

    Lu, Qi; Yi, Xin; Cheng, Xiang; Sun, Xiaohui; Yang, Xiangjun

    2015-04-01

    Melatonin is thought to have the ability of antiatherogenic, antioxidant, and vasodilatory. It is not only a promising protective in acute myocardial infarction but is also a useful tool in the treatment of pathological remodeling. However, its role in myocardial hypertrophy remains unclear. In this study, we investigated the protective effects of melatonin on myocardial hypertrophy induced by lipopolysaccharide (LPS) and to identify their precise mechanisms. The cultured myocardial cell was divided into six groups: control group, LPS group, LPS + ethanol (4%), LPS + melatonin (1.5 mg/ml) group, LPS + melatonin (3 mg/ml) group, and LPS + melatonin (6 mg/ml) group. The morphologic change of myocardial cell was observed by inverted phase contrast microscope. The protein level of myocardial cell was measured by Coomassie brilliant blue protein kit. The secretion level of tumor necrosis factor-α (TNF-α) was evaluated by enzyme-linked immunosorbent assay (ELISA). Ca(2+) transient in Fura-2/AM-loaded cells was measured by Till image system. The expression of Ca(2+)/calmodulin-dependent kinase II (CaMKII) and calcineurin (CaN) was measured by Western blot analysis. Our data demonstrated that LPS induced myocardial hypertrophy, promoted the secretion levels of TNF-α, and increased Ca(2+) transient level and the expression of CaMKII and CaN. Administration of melatonin 30 min prior to LPS stimulation dose-dependently attenuated myocardial hypertrophy. In conclusion, the results revealed that melatonin had the potential to protect against myocardial hypertrophy induced by LPS in vitro through downregulation of the TNF-α expression and retains the intracellular Ca(2+) homeostasis.

  14. Minocycline protects against lipopolysaccharide-induced cognitive impairment in mice.

    Science.gov (United States)

    Hou, Yue; Xie, Guanbo; Liu, Xia; Li, Guoxun; Jia, Congcong; Xu, Jinghua; Wang, Bing

    2016-03-01

    The role of glial cells, especially microglia and astrocytes, in neuroinflammation and cognition has been studied intensively. Lipopolysaccharide (LPS), a commonly used inducer of neuroinflammation, can cause cognitive impairment. Minocycline is known to possess potent neuroprotective activity, but its effect on LPS-induced cognitive impairment is unknown. This study aims to investigate the effects of minocycline on LPS-induced cognitive impairment and glial cell activation in mice. Behavioral tests were conducted for cognitive function, immunohistochemistry for microglial and astrocyte response, and quantitative PCR for mRNA expression of proinflammatory cytokines. Minocycline significantly reversed the decreased spontaneous alternation induced by intrahippocampal administration of LPS in the Y-maze task. In the Morris water maze place navigation test, minocycline decreased the escape latency and distance traveled compared to LPS-treated mice. In the probe test, minocycline-treated mice spent more time in the target quadrant and crossed the platform area more frequently than animals in the LPS-treated group. Minocycline produced a significant decrease in the number of Iba-1- and GFAP-positive hippocampal cells compared to the LPS-treated group. Minocycline-treated mice had significantly reduced hippocampal TNF-α and IL-1β mRNA levels compared with LPS-treated animals. Minocycline caused a significant increase in hippocampal BDNF expression compared to the LPS-treated group. Minocycline can attenuate LPS-induced cognitive impairments in mice. This effect may be associated with its action to suppress the activation of microglia and astrocytes and to normalize BDNF expression. Since neuroinflammatory processes and cognitive impairments are implicated in neurodegenerative disorders, minocycline may be a promising candidate for treating such diseases.

  15. P. aeruginosa in the paranasal sinuses and transplanted lungs have similar adaptive mutations as isolates from chronically infected CF lungs

    DEFF Research Database (Denmark)

    Ciofu, Oana; Johansen, Helle Krogh; Aanaes, Kasper

    2013-01-01

    BACKGROUND: Pseudomonas aeruginosa cells are present as biofilms in the paranasal sinuses and the lungs of chronically infected cystic fibrosis (CF) patients. Since different inflammatory responses and selective antibiotic pressures are acting in the sinuses compared with the lungs, we compared...... the adaptive profiles of mucoid and non-mucoid isolates from the two locations. METHODS: We studied the genetic basis of phenotypic diversification and gene expression profiles in sequential lung and sinus P. aeruginosa isolates from four chronically infected CF patients, including pre- and post-lung...... transplantation isolates. RESULTS: The same phenotypes caused by similar mutations and similar gene expression profiles were found in mucoid and non-mucoid isolates from the paranasal sinuses and from the lungs before and after transplantation. CONCLUSION: Bilateral exchange of P. aeruginosa isolates between...

  16. Dopamine-dependent neurotoxicity of lipopolysaccharide in substantia nigra.

    Science.gov (United States)

    De Pablos, Rocío M; Herrera, Antonio J; Villarán, Ruth F; Cano, Josefina; Machado, Alberto

    2005-03-01

    Intranigral injection of lipopolysaccharide (LPS), a potent inductor of inflammation, induces degeneration of dopaminergic neurons, along with an inflammatory process that features activation of microglial cells and loss of astrocytes. To test the involvement of dopamine (DA) in this degeneration induced by LPS, we treated albino Wistar rats with different concentrations of alpha-methyl-p-tyrosine (alpha-MPT), an inhibitor of tyrosine hydroxylase (TH) activity. Results showed that alpha-MPT prevented LPS-induced loss of TH immunostaining and expression of mRNA for TH and DA transporter; it also prevented substantial activation of microglial cells. Loss of the astroglial population, a marker of damage in our model, was also prevented. This protective effect resulted from inhibition of TH and the consequent decrease in DA concentration, because treatment with L-DOPA/benserazide, which bypasses TH inhibition induced by alpha-MPT, reversed the protective effect produced by this drug. These results point out the important contribution of DA to the vulnerability and degeneration of dopaminergic neurons of the substantia nigra. Knowledge about the involvement of DA in this process may lead to the possibility of new protection strategies against this important degenerative process.

  17. Burden of different beta-lactamase classes among clinical isolates of AmpC-producing Pseudomonas aeruginosa in burn patients: A prospective study

    OpenAIRE

    Kumar, V.; Sen, M. R.; Nigam, C.; Gahlot, R.; Kumari, S.

    2012-01-01

    Background: Pseudomonas aeruginosa is one of the most common pathogens causing infections in burns, and shows increasing resistance to β-lactam antibiotics by producing different classes of beta-lactamases. It is also not unusual to find a single isolate that expresses multiple β-lactamase enzymes, further complicating the treatment options. Thus, in this study, we aimed to determine the coexistence of different beta-lactamase enzymes in clinical isolates of P. aeruginosa in the burn ward. Ma...

  18. Porphyromonas endodontalis lipopolysaccharides induce RANKL by mouse osteoblast in a way different from that of Escherichia coli lipopolysaccharide.

    Science.gov (United States)

    Tang, Yin; Sun, Feifei; Li, Xiaoting; Zhou, Yuan; Yin, Shihai; Zhou, Xuedong

    2011-12-01

    Porphyromonas endodontalis lipopolysaccharide (LPS) has been shown to have a high positive rate in infected root canals and symptomatic apical periodontitis. It may play an integral role as a potent stimulator of inflammatory cytokines involved in apical lesions. The receptor activator of nuclear factor-κB ligand (RANKL) has been proven to be the key regulator of bone remodeling. This study investigated P. endodontalis LPS-induced RANKL production and LPS signaling in mouse osteoblasts. LPS-induced RANKL production in mouse osteoblast MC3T3-E1 cells was measured by Western blot and real-time polymerase chain reaction, and the Toll-like receptors (TLRs) were determined by the blocking test using anti-TLRs antibodies. In addition, specific inhibitors were used to analyze the intracellular signaling pathways. Escherichia coli LPS was used as the control. Both of the anti-TLR2 and anti-TLR4 antibodies significantly (P endodontalis LPS; only anti-TLR2 antibody had a significant (P endodontalis LPS-infected osteoblasts (P endodontalis LPS has the ability to promote the expression of RANKL in mouse osteoblasts, and this induction was mainly through the TLR2/4-JNK signaling pathway, a situation quite different from that of typical bacterial endotoxin (E. coli LPS). Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  19. Structure and activity of the Pseudomonas aeruginosa hotdog-fold thioesterases PA5202 and PA2801.

    Science.gov (United States)

    Gonzalez, Claudio F; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Evdokimova, Elena; Xu, Xiaohui; Osipiuk, Jerzy; Cuff, Marianne E; Lynch, Susan; Joachimiak, Andrzej; Savchenko, Alexei; Yakunin, Alexander F

    2012-06-15

    The hotdog fold is one of the basic protein folds widely present in bacteria, archaea and eukaryotes. Many of these proteins exhibit thioesterase activity against fatty acyl-CoAs and play important roles in lipid metabolism, cellular signalling and degradation of xenobiotics. The genome of the opportunistic pathogen Pseudomonas aeruginosa contains over 20 genes encoding predicted hotdog-fold proteins, none of which have been experimentally characterized. We have found that two P. aeruginosa hotdog proteins display high thioesterase activity against 3-hydroxy-3-methylglutaryl-CoA and glutaryl-CoA (PA5202), and octanoyl-CoA (PA2801). Crystal structures of these proteins were solved (at 1.70 and 1.75 Å for PA5202 and PA2801 respectively) and revealed a hotdog fold with a potential catalytic carboxylate residue located on the long α-helix (Asp(57) in PA5202 and Glu(35) in PA2801). Alanine residue replacement mutagenesis of PA5202 identified four residues (Asn(42), Arg(43), Asp(57) and Thr(76)) that are critical for its activity and are located in the active site. A P. aeruginosa PA5202 deletion strain showed an increased secretion of the antimicrobial pigment pyocyanine and an increased expression of genes involved in pyocyanin biosynthesis, suggesting a functional link between PA5202 activity and pyocyanin production. Thus the P. aeruginosa hotdog thioesterases PA5202 and PA2801 have similar structures, but exhibit different substrate preferences and functions.

  20. Label-free molecular imaging of bacterial communities of the opportunistic pathogen Pseudomonas aeruginosa

    Science.gov (United States)

    Baig, Nameera; Polisetti, Sneha; Morales-Soto, Nydia; Dunham, Sage J. B.; Sweedler, Jonathan V.; Shrout, Joshua D.; Bohn, Paul W.

    2016-09-01

    Biofilms, such as those formed by the opportunistic human pathogen Pseudomonas aeruginosa are complex, matrix enclosed, and surface-associated communities of cells. Bacteria that are part of a biofilm community are much more resistant to antibiotics and the host immune response than their free-floating counterparts. P. aeruginosa biofilms are associated with persistent and chronic infections in diseases such as cystic fibrosis and HIV-AIDS. P. aeruginosa synthesizes and secretes signaling molecules such as the Pseudomonas quinolone signal (PQS) which are implicated in quorum sensing (QS), where bacteria regulate gene expression based on population density. Processes such as biofilms formation and virulence are regulated by QS. This manuscript describes the powerful molecular imaging capabilities of confocal Raman microscopy (CRM) and surface enhanced Raman spectroscopy (SERS) in conjunction with multivariate statistical tools such as principal component analysis (PCA) for studying the spatiotemporal distribution of signaling molecules, secondary metabolites and virulence factors in biofilm communities of P. aeruginosa. Our observations reveal that the laboratory strain PAO1C synthesizes and secretes 2-alkyl-4-hydroxyquinoline N-oxides and 2-alkyl-4-hydroxyquinolones in high abundance, while the isogenic acyl homoserine lactone QS-deficient mutant (ΔlasIΔrhlI) strain produces predominantly 2-alkyl-quinolones during biofilm formation. This study underscores the use of CRM, along with traditional biological tools such as genetics, for studying the behavior of microbial communities at the molecular level.

  1. Genome-wide screen of Pseudomonas aeruginosa In Saccharomyces cerevisiae identifies new virulence factors

    Directory of Open Access Journals (Sweden)

    Rafat eZrieq

    2015-11-01

    Full Text Available Pseudomonas aeruginosa is a human opportunistic pathogen that causes mortality in cystic fibrosis and immunocompromised patients. While many virulence factors of this pathogen have already been identified, several remain to be discovered. In this respect we set an unprecedented genome-wide screen of a P. aeruginosa expression library based on a yeast growth phenotype. 51 candidates were selected in a three-round screening process. The robustness of the screen was validated by the selection of three well known secreted proteins including one demonstrated virulence factor, the protease LepA. Further in silico sorting of the 51 candidates highlighted three potential new Pseudomonas effector candidates (Pec. By testing the cytotoxicity of wild type P. aeruginosa vs pec mutants towards macrophages and the virulence in the Caenorhabditis elegans model, we demonstrated that the three selected Pecs are novel virulence factors of P. aeruginosa. Additional cellular localization experiments in the host revealed specific localization for Pec1 and Pec2 that could inform about their respective functions.

  2. Subinhibitory concentration of kanamycin induces the Pseudomonas aeruginosa type VI secretion system.

    Directory of Open Access Journals (Sweden)

    Cerith Jones

    Full Text Available Pseudomonas aeruginosa is a Gram-negative bacterium found in natural environments including plants, soils and warm moist surfaces. This organism is also in the top ten of nosocomial pathogens, and prevalent in cystic fibrosis (CF lung infections. The ability of P. aeruginosa to colonize a wide variety of environments in a lasting manner is associated with the formation of a resistant biofilm and the capacity to efficiently outcompete other microorganisms. Here we demonstrate that sub-inhibitory concentration of kanamycin not only induces biofilm formation but also induces expression of the type VI secretion genes in the H1-T6SS cluster. The H1-T6SS is known for its role in toxin production and bacterial competition. We show that the antibiotic induction of the H1-T6SS only occurs when a functional Gac/Rsm pathway is present. These observations may contribute to understand how P. aeruginosa responds to antibiotic producing competitors. It also suggests that improper antibiotic therapy may enhance P. aeruginosa colonization, including in the airways of CF patients.

  3. Archetypal analysis of diverse Pseudomonas aeruginosa transcriptomes reveals adaptation in cystic fibrosis airways

    DEFF Research Database (Denmark)

    Thøgersen, Juliane Charlotte; Mørup, Morten; Pedersen, Søren Damkiær

    2013-01-01

    is to introduce a method for DNA microarray analysis that provides an intuitive interpretation of data through dimension reduction and pattern recognition. We present the first “Archetypal Analysis” of global gene expression. The analysis is based on microarray data from five integrated studies of Pseudomonas...... aeruginosa isolated from the airways of cystic fibrosis patients. RESULTS: Our analysis clustered samples into distinct groups with comprehensible characteristics since the archetypes representing the individual groups are closely related to samples present in the data set. Significant changes in gene....... This suggests positive selection in the cystic fibrosis lung environment, and changes in gene expression for these isolates are therefore most likely related to adaptation of the bacteria. CONCLUSIONS: Archetypal analysis succeeded in identifying adaptive changes of P. aeruginosa. The combination of clustering...

  4. Prolonged neuroinflammation after lipopolysaccharide exposure in aged rats.

    Directory of Open Access Journals (Sweden)

    Hui Qun Fu

    Full Text Available Inflammation is a hallmark of several disease states ranging from neurodegeneration to sepsis but is also implicated in physiological processes like ageing. Non-resolving inflammation and prolonged neuroinflammation are unclear processes implicated in several conditions, including ageing. In this study we studied the long-term effects of endotoxemia, as systemic lipopolysaccharide (LPS injection, focusing on the role of astrocyte activation and cytokine release in the brain of aged rats. A single dose of LPS (2 mg/kg or 0.9% saline was injected intraperitoneally in aged rats. Levels of pro-inflammatory cytokines (TNFα and IL-1β and NF-κB p65 activation were measured systemically and in hippocampal tissue. Astrocytes and cytokines release in the CNS were detected via double immunofluorescence staining at different time-points up to day 30. Serum levels of TNFα and IL-1β were significantly increased acutely after 30 minutes (p<0.001 and up to 6 hours (p<0.001 following LPS-injection. Centrally, LPS-treated rats showed up-regulated mRNA expression and protein levels of pro-inflammatory cytokines in the hippocampus. These changes associated with astrogliosis in the hippocampus dentate gyrus (DG, IL-1β immunoreactivity and elevated NF-κB p65 expression up to day 30 post LPS exposure. Overall, these data demonstrate that LPS induces prolonged neuroinflammation and astrocyte activation in the hippocampus of aged rats. Hippocampal NF-κB p65 and excessive astrocytes-derived IL-1β release may play a pivotal role in regulating long-lasting neuroinflammation.

  5. Characterization of Pseudomonas aeruginosa chitinase, a gradually secreted protein.

    Science.gov (United States)

    Folders, J; Algra, J; Roelofs, M S; van Loon, L C; Tommassen, J; Bitter, W

    2001-12-01

    The gram-negative bacterium Pseudomonas aeruginosa secretes many proteins into its extracellular environment via the type I, II, and III secretion systems. In this study, a gene, chiC, coding for an extracellular chitinolytic enzyme, was identified. The chiC gene encodes a polypeptide of 483 amino acid residues, without a typical N-terminal signal sequence. Nevertheless, an N-terminal segment of 11 residues was found to be cleaved off in the secreted protein. The protein shows sequence similarity to the secreted chitinases ChiC of Serratia marcescens, ChiA of Vibrio harveyi, and ChiD of Bacillus circulans and consists of an activity domain and a chitin-binding domain, which are separated by a fibronectin type III domain. ChiC was able to bind and degrade colloidal chitin and was active on the artificial substrates carboxymethyl-chitin-Remazol Brilliant Violet and p-nitrophenyl-beta-D-N,N',N"-triacetylchitotriose, but not on p-nitrophenyl-beta-D-N-acetylglucosamine, indicating that it is an endochitinase. Expression of the chiC gene appears to be regulated by the quorum-sensing system of P. aeruginosa, since this gene was not expressed in a lasIR vsmI mutant. After overnight growth, the majority of the ChiC produced was found intracellularly, whereas only small amounts were detected in the culture medium. However, after several days, the cellular pool of ChiC was largely depleted, and the protein was found in the culture medium. This release could not be ascribed to cell lysis. Since ChiC did not appear to be secreted via any of the known secretion systems, a novel secretion pathway seems to be involved.

  6. The Pseudomonas aeruginosa pirA gene encodes a second receptor for ferrienterobactin and synthetic catecholate analogues.

    Science.gov (United States)

    Ghysels, Bart; Ochsner, Urs; Möllman, Ute; Heinisch, Lothar; Vasil, Michael; Cornelis, Pierre; Matthijs, Sandra

    2005-05-15

    Actively secreted iron chelating agents termed siderophores play an important role in the virulence and rhizosphere competence of fluorescent pseudomonads, including Pseudomonas aeruginosa which secretes a high affinity siderophore, pyoverdine, and the low affinity siderophore, pyochelin. Uptake of the iron-siderophore complexes is an active process that requires specific outer membrane located receptors, which are dependent of the inner membrane-associated protein TonB and two other inner membrane proteins, ExbB and ExbC. P. aeruginosa is also capable of using a remarkable variety of heterologous siderophores as sources of iron, apparently by expressing their cognate receptors. Illustrative of this feature are the 32 (of which 28 putative) siderophore receptor genes observed in the P. aeruginosa PAO1 genome. However, except for a few (pyoverdine, pyochelin, enterobactin), the vast majority of P. aeruginosa siderophore receptor genes still remain to be characterized. Ten synthetic iron chelators of catecholate type stimulated growth of a pyoverdine/pyochelin deficient P. aeruginosa PAO1 mutant under condition of severe iron limitation. Null mutants of the 32 putative TonB-dependent siderophore receptor encoding genes engineered in the same genetic background were screened for obvious deficiencies in uptake of the synthetic siderophores, but none showed decreased growth stimulation in the presence of the different siderophores. However, a double knock-out mutant of ferrienterobactin receptor encoding gene pfeA (PA 2688) and pirA (PA0931) failed to be stimulated by 4 of the tested synthetic catecholate siderophores whose chemical structures resemble enterobactin. Ferric-enterobactin also failed to stimulate growth of the double pfeA-pirA mutant although, like its synthetic analogues, it stimulated growth of the corresponding single mutants. Hence, we confirmed that pirA represents a second P. aeruginosa ferric-enterobactin receptor. The example of these two

  7. A novel podocyte gene, semaphorin 3G, protects glomerular podocyte from lipopolysaccharide-induced inflammation.

    Science.gov (United States)

    Ishibashi, Ryoichi; Takemoto, Minoru; Akimoto, Yoshihiro; Ishikawa, Takahiro; He, Peng; Maezawa, Yoshiro; Sakamoto, Kenichi; Tsurutani, Yuya; Ide, Shintaro; Ide, Kana; Kawamura, Harukiyo; Kobayashi, Kazuki; Tokuyama, Hirotake; Tryggvason, Karl; Betsholtz, Christer; Yokote, Koutaro

    2016-05-16

    Kidney diseases including diabetic nephropathy have become huge medical problems, although its precise mechanisms are still far from understood. In order to increase our knowledge about the patho-physiology of kidney, we have previously identified >300 kidney glomerulus-enriched transcripts through large-scale sequencing and microarray profiling of the mouse glomerular transcriptome. One of the glomerulus-specific transcripts identified was semaphorin 3G (Sema3G) which belongs to the semaphorin family. The aim of this study was to analyze both the in vivo and in vitro functions of Sema3G in the kidney. Sema3G was expressed in glomerular podocytes. Although Sema3G knockout mice did not show obvious glomerular defects, ultrastructural analyses revealed partially aberrant podocyte foot processes structures. When these mice were injected with lipopolysaccharide to induce acute inflammation or streptozotocin to induce diabetes, the lack of Sema3G resulted in increased albuminuria. The lack of Sema3G in podocytes also enhanced the expression of inflammatory cytokines including chemokine ligand 2 and interleukin 6. On the other hand, the presence of Sema3G attenuated their expression through the inhibition of lipopolysaccharide-induced Toll like receptor 4 signaling. Taken together, our results surmise that the Sema3G protein is secreted by podocytes and protects podocytes from inflammatory kidney diseases and diabetic nephropathy.

  8. Activation of Pseudomonas aeruginosa elastase in Pseudomonas putida by triggering dissociation of the propeptide-enzyme complex

    NARCIS (Netherlands)

    Braun, P; Bitter, W; Tommassen, J

    2000-01-01

    The propeptide of Pseudomonas aeruginosa elastase functions both as an intramolecular chaperone required for the folding of the enzyme and as an inhibitor that prevents activity of the enzyme before its secretion into the extracellular medium. Since expression of the lasB gene, which encodes

  9. Expression

    Directory of Open Access Journals (Sweden)

    Wang-Xia Wang

    2014-02-01

    Full Text Available The miR-15/107 family comprises a group of 10 paralogous microRNAs (miRNAs, sharing a 5′ AGCAGC sequence. These miRNAs have overlapping targets. In order to characterize the expression of miR-15/107 family miRNAs, we employed customized TaqMan Low-Density micro-fluid PCR-array to investigate the expression of miR-15/107 family members, and other selected miRNAs, in 11 human tissues obtained at autopsy including the cerebral cortex, frontal cortex, primary visual cortex, thalamus, heart, lung, liver, kidney, spleen, stomach and skeletal muscle. miR-103, miR-195 and miR-497 were expressed at similar levels across various tissues, whereas miR-107 is enriched in brain samples. We also examined the expression patterns of evolutionarily conserved miR-15/107 miRNAs in three distinct primary rat brain cell preparations (enriched for cortical neurons, astrocytes and microglia, respectively. In primary cultures of rat brain cells, several members of the miR-15/107 family are enriched in neurons compared to other cell types in the central nervous system (CNS. In addition to mature miRNAs, we also examined the expression of precursors (pri-miRNAs. Our data suggested a generally poor correlation between the expression of mature miRNAs and their precursors. In summary, we provide a detailed study of the tissue and cell type-specific expression profile of this highly expressed and phylogenetically conserved family of miRNA genes.

  10. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  11. Pseudomonas aeruginosa ventilator-associated pneumonia management

    Science.gov (United States)

    Ramírez-Estrada, Sergio; Borgatta, Bárbara; Rello, Jordi

    2016-01-01

    Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising. PMID:26855594

  12. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

    The persistence of chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients is due to biofilm-growing mucoid (alginate-producing) strains. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein...... and DNA. In CF lungs, the polysaccharide alginate is the major part of the P. aeruginosa biofilm matrix. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and resist phagocytosis, as well as other components of the innate and the adaptive immune system....... As a consequence, a pronounced antibody response develops, leading to immune complex-mediated chronic inflammation, dominated by polymorphonuclear leukocytes. The chronic inflammation is the major cause of the lung tissue damage in CF. Biofilm growth in CF lungs is associated with an increased frequency...

  13. Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

    Directory of Open Access Journals (Sweden)

    Kalpana Badami Nagaraj

    2013-01-01

    Full Text Available A 65-year-old male presented with decreased vision in the left eye of 15-day duration after having undergone an uneventful cataract surgery 10 months back. He had been previously treated with systemic steroids for recurrent uveitis postoperatively on three occasions in the same eye. B-scan ultrasonography showed multiple clumplike echoes suggestive of vitreous inflammation. Aqueous tap revealed Pseudomonas aeruginosa sensitive to ciprofloxacin. The patient was treated with intravitreal ciprofloxacin and vancomycin along with systemic ciprofloxacin with good clinical response. Even a virulent organism such as P.aeruginosa can present as a chronic uveitis, which, if missed, can lead to a delay in accurate diagnosis and appropriate management.

  14. The Pseudomonas aeruginosa transcriptome in planktonic cultures and static biofilms using RNA sequencing.

    Directory of Open Access Journals (Sweden)

    Andreas Dötsch

    Full Text Available In this study, we evaluated how gene expression differs in mature Pseudomonas aeruginosa biofilms as opposed to planktonic cells by the use of RNA sequencing technology that gives rise to both quantitative and qualitative information on the transcriptome. Although a large proportion of genes were consistently regulated in both the stationary phase and biofilm cultures as opposed to the late exponential growth phase cultures, the global biofilm gene expression pattern was clearly distinct indicating that biofilms are not just surface attached cells in stationary phase. A large amount of the genes found to be biofilm specific were involved in adaptation to microaerophilic growth conditions, repression of type three secretion and production of extracellular matrix components. Additionally, we found many small RNAs to be differentially regulated most of them similarly in stationary phase cultures and biofilms. A qualitative analysis of the RNA-seq data revealed more than 3000 putative transcriptional start sites (TSS. By the use of rapid amplification of cDNA ends (5'-RACE we confirmed the presence of three different TSS associated with the pqsABCDE operon, two in the promoter of pqsA and one upstream of the second gene, pqsB. Taken together, this study reports the first transcriptome study on P. aeruginosa that employs RNA sequencing technology and provides insights into the quantitative and qualitative transcriptome including the expression of small RNAs in P. aeruginosa biofilms.

  15. Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis.

    Science.gov (United States)

    Mateos, I; Valencia, R; Torres, M J; Cantos, A; Conde, M; Aznar, J

    2006-11-01

    We describe an outbreak of nosocomial endophthalmitis due to a common source, which was determined to be trypan blue solution prepared in the hospital's pharmacy service. We assume that viable bacteria probably gained access to the trypan blue stock solution during cooling after autoclaving. The temporal cluster of Pseudomonas aeruginosa endophthalmitis was readily perceived on the basis of clinical and microbiological findings, and an exogenous source of contamination was unequivocally identified by means of DNA fingerprinting.

  16. Development of a Pseudomonas aeruginosa Agmatine Biosensor

    OpenAIRE

    Gilbertsen, Adam; Williams, Bryan

    2014-01-01

    Agmatine, decarboxylated arginine, is an important intermediary in polyamine production for many prokaryotes, but serves higher functions in eukaryotes such as nitric oxide inhibition and roles in neurotransmission. Pseudomonas aeruginosa relies on the arginine decarboxylase and agmatine deiminase pathways to convert arginine into putrescine. One of the two known agmatine deiminase operons, aguBA, contains an agmatine sensitive TetR promoter controlled by AguR. We have discovered that this pr...

  17. Genetics of Persister Formation in Pseudomonas aeruginosa

    Science.gov (United States)

    2012-12-14

    situation where P. aeruginosa infects the airways. Intubated patients are at risk for developing ventilator-associated pneumonia ( VAP ), which can develop...infects the airways. Intubated patients are at risk for developing ventilator-associated pneumonia ( VAP ), which can develop into a chronic...Department of the Army position , policy or decision, unless so designated by other documentation. 12. DISTRIBUTION AVAILIBILITY STATEMENT Approved for Public

  18. Characterization of the Pseudomonas aeruginosa Lol system as a lipoprotein sorting mechanism.

    Science.gov (United States)

    Tanaka, Shin-Ya; Narita, Shin-Ichiro; Tokuda, Hajime

    2007-05-04

    Escherichia coli lipoproteins are localized to either the inner or the outer membrane depending on the residue that is present next to the N-terminal acylated Cys. Asp at position 2 causes the retention of lipoproteins in the inner membrane. In contrast, the accompanying study (9) revealed that the residues at positions 3 and 4 determine the membrane specificity of lipoproteins in Pseudomonas aeruginosa. Since the five Lol proteins involved in the sorting of E. coli lipoproteins are conserved in P. aeruginosa, we examined whether or not the Lol proteins of P. aeruginosa are also involved in lipoprotein sorting but utilize different signals. The genes encoding LolCDE, LolA, and LolB homologues were cloned and expressed. The LolCDE homologue thus purified was reconstituted into proteoliposomes with lipoproteins. When incubated in the presence of ATP and a LolA homologue, the reconstituted LolCDE homologue released lipoproteins, leading to the formation of a LolA-lipoprotein complex. Lipoproteins were then incorporated into the outer membrane depending on a LolB homologue. As revealed in vivo, lipoproteins with Lys and Ser at positions 3 and 4, respectively, remained in proteoliposomes. On the other hand, E. coli LolCDE released lipoproteins with this signal and transferred them to LolA of not only E. coli but also P. aeruginosa. These results indicate that Lol proteins are responsible for the sorting of lipoproteins to the outer membrane of P. aeruginosa, as in the case of E. coli, but respond differently to inner membrane retention signals.

  19. Effects of ginseng on Pseudomonas aeruginosa motility and biofilm formation

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang

    2011-01-01

    protected animal models from developing chronic lung infection by P. aeruginosa. In the present study, the effects of ginseng on the formation of P. aeruginosa biofilms were further investigated in vitro and in vivo. Ginseng aqueous extract at concentrations of 0.5-2.0% did not inhibit the growth of P......Biofilm-associated chronic Pseudomonas aeruginosa lung infections in patients with cystic fibrosis are virtually impossible to eradicate with antibiotics because biofilm-growing bacteria are highly tolerant to antibiotics and host defense mechanisms. Previously, we found that ginseng treatments....... aeruginosa, but significantly prevented P. aeruginosa from forming biofilm. Exposure to 0.5% ginseng aqueous extract for 24 h destroyed most 7-day-old mature biofilms formed by both mucoid and nonmucoid P. aeruginosa strains. Ginseng treatment enhanced swimming and twitching motility, but reduced swarming...

  20. Hydrolysis of cefazolin by enzymes produced by Pseudomonas aeruginosa after exposure to ceftazidime in vitro

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    Papaioannidou Paraskevi

    2009-01-01

    Full Text Available Background/Aim. Sometimes resistance of Pseudomonas aeruginosa (Ps. aeruginosa is developed during antibiotic treatment, in spite of the initial susceptibility in vitro. The aim of this study was to use an in vitro model for the study of the development of resistant strains of Ps. aeruginosa after a short exposure to ceftazidime, and to study the hydrolysing capacity of β-lactamases produced by the resistant strains. Methods. Among 563 clinical strains of Ps. aeruginosa, 37 multisensitive strains were collected for the study. After being identified, strains with simultaneous sensitivity to 5 expanded spectrum cephalosporins were chosen. For each strain, the minimal inhibitory concentration (MIC of the 5 expanded spectrum cephalosporins was determined, and the production of extended spectrum β-lactamases (ESBL was excluded by the double-disc synergy diffusion test. Strains non producing ESBL were cultivated in concentrations of ceftazidime equal to MIC×2 and MIC×4. After 24 hours of culture, the development of resistant strains was estimated and the cephalosporinase activity of the produced β-lactamases was determined by their ability to hydrolyse cefazolin. Hydrolysis of cefazolin was studied by measuring the change of its absorbance on 272 nm using a Shimadzu 160A spectrophotometer. The hydrolyzing capacity of the enzymes was expressed as the percentage of the antibiotic, which was hydrolysed in 10 sec. Results. A total of 60% and 50% of strains developed resistant strains after exposure to ceftazidime in concentration MIC×2 and MIC×4, respectively. The hydrolyzing capacity of the original strains was 15-36% while the hydrolyzing capacity of the resistant strains was 10-73%. Totally 64% of the resistant strains expressed higher hydrolyzing capacity than the original strains. Conclusion. Regardless of the susceptibility test results, Ps. aeruginosa presented a high tendency to develop resistant strains after a short exposure to

  1. Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

    Science.gov (United States)

    Cross, Megan; Biberacher, Sonja; Park, Suk-Youl; Rajan, Siji; Korhonen, Pasi; Gasser, Robin B; Kim, Jeong-Sun; Coster, Mark J; Hofmann, Andreas

    2018-04-24

    The opportunistic bacterium Pseudomonas aeruginosa has been recognized as an important pathogen of clinical relevance and is a leading cause of hospital-acquired infections. The presence of a glycolytic enzyme in Pseudomonas, which is known to be inhibited by trehalose 6-phosphate (T6P) in other organisms, suggests that these bacteria may be vulnerable to the detrimental effects of intracellular T6P accumulation. In the present study, we explored the structural and functional properties of trehalose 6-phosphate phosphatase (TPP) in P. aeruginosa in support of future target-based drug discovery. A survey of genomes revealed the existence of 2 TPP genes with either chromosomal or extrachromosomal location. Both TPPs were produced as recombinant proteins, and characterization of their enzymatic properties confirmed specific, magnesium-dependent catalytic hydrolysis of T6P. The 3-dimensional crystal structure of the chromosomal TPP revealed a protein dimer arising through β-sheet expansion of the individual monomers, which possess the overall fold of halo-acid dehydrogenases.-Cross, M., Biberacher, S., Park, S.-Y., Rajan, S., Korhonen, P., Gasser, R. B., Kim, J.-S., Coster, M. J., Hofmann, A. Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

  2. Antivirulence activity of azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Francesco eImperi

    2014-04-01

    Full Text Available Antibiotics represent our bulwark to combat bacterial infections, but the spread of antibiotic resistance compromises their clinical efficacy. Alternatives to conventional antibiotics are urgently needed in order to complement the existing antibacterial arsenal. The macrolide antibiotic azithromycin (AZM provides a paradigmatic example of an unconventional antibacterial drug. Besides its growth-inhibiting activity, AZM displays potent anti-inflammatory properties, as well as antivirulence activity on some intrinsically resistant bacteria, such as Pseudomonas aeruginosa. In this bacterium, the antivirulence activity of AZM mainly relies on its ability to interact with the ribosome, resulting in direct and/or indirect repression of specific subsets of genes involved in virulence, quorum sensing, biofilm formation and intrinsic antibiotic resistance. Both clinical experience and clinical trials have shown the efficacy of AZM in the treatment of chronic pulmonary infections caused by P. aeruginosa. The aim of this review is to combine results from laboratory studies with evidence from clinical trials in order to unify the information on the in vivo mode of action of AZM in P. aeruginosa infection.

  3. Development of a Pseudomonas aeruginosa Agmatine Biosensor

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    Adam Gilbertsen

    2014-10-01

    Full Text Available Agmatine, decarboxylated arginine, is an important intermediary in polyamine production for many prokaryotes, but serves higher functions in eukaryotes such as nitric oxide inhibition and roles in neurotransmission. Pseudomonas aeruginosa relies on the arginine decarboxylase and agmatine deiminase pathways to convert arginine into putrescine. One of the two known agmatine deiminase operons, aguBA, contains an agmatine sensitive TetR promoter controlled by AguR. We have discovered that this promoter element can produce a titratable induction of its gene products in response to agmatine, and utilized this discovery to make a luminescent agmatine biosensor in P. aeruginosa. The genome of the P. aeruginosa lab strain UCBPP-PA14 was altered to remove both its ability to synthesize or destroy agmatine, and insertion of the luminescent reporter construct allows it to produce light in proportion to the amount of exogenous agmatine applied from ~100 nM to 1mM. Furthermore it does not respond to related compounds including arginine or putrescine. To demonstrate potential applications the biosensor was used to detect agmatine in spent supernatants, to monitor the development of arginine decarboxylase over time, and to detect agmatine in the spinal cords of live mice.

  4. Pseudomonas aeruginosa induces pigment production and enhances virulence in a white phenotypic variant of Staphylococcus aureus

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    Antonic V

    2013-11-01

    Full Text Available Vlado Antonic,1–3 Alexander Stojadinovic,3–5 Binxue Zhang,1–3 Mina J Izadjoo,1–3,5 Mohammad Alavi1–3 1Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA; 2Diagnostic and Translational Research Center, Gaithersburg, MD, USA; 3Combat Wound Initiative Program, Bethesda, MD, USA; 4Walter Reed National Military Medical Center, Bethesda, MD, USA; 5Uniformed Services University of the Health Sciences, Bethesda, MD, USA Abstract: Staphyloxanthin is a virulence factor which protects Staphylococcus aureus in stress conditions. We isolated two pigment variants of S. aureus and one strain of Pseudomonas aeruginosa from a single wound infection. S. aureus variants displayed white and yellow colony phenotypes. The sequence of the operons for staphyloxanthin synthesis indicated that coding and promoter regions were identical between the two pigment variants. Quorum sensing controls pigment synthesis in some bacteria. It is also shown that P. aeruginosa quorum-sensing molecules affect S. aureus transcription. We explored whether the co-infecting P. aeruginosa can affect pigment production in the white S. aureus variant. In co-culture experiments between the white variants and a selected number of Gram-positive and Gram-negative bacteria, only P. aeruginosa induced pigment production in the white variant. Gene expression analysis of the white variant did not indicate upregulation of the crtM and other genes known to be involved in pigment production (sigB, sarA, farnesyl pyrophosphate synthase gene [FPP-synthase], hfq. In contrast, transcription of the catalase gene was significantly upregulated after co-culture. P. aeruginosa-induced pigment synthesis and catalase upregulation correlated with increased resistance to polymyxin B, hydrogen peroxide, and the intracellular environment of macrophages. Our data indicate the presence of silent but functional staphyloxanthin synthesis machinery in a white phenotypic variant

  5. Exploring the In Vitro Thrombolytic Activity of Nattokinase From a New Strain Pseudomonas aeruginosa CMSS.

    Science.gov (United States)

    Chandrasekaran, Subathra Devi; Vaithilingam, Mohanasrinivasan; Shanker, Ravi; Kumar, Sanjeev; Thiyur, Swathi; Babu, Vaishnavi; Selvakumar, Jemimah Naine; Prakash, Suyash

    2015-10-01

    Thrombolytic therapy has become a conventional treatment for acute myocardial infarction (AMI), yet currently, clinically prescribed thrombolytic drugs have problems such as delayed action and other side effects. Fibrinolytic enzymes have attracted interest as thrombolytic agents because of their efficiency in the fibrinolytic process, including plasmin activation. Nattokinase (NK) is a potent fibrinolytic agent for thrombosis therapy. The aim of this study was to enhance the production of NK from Pseudomonas aeruginosa CMSS by media optimization and strain improvement. In the present study, a potent NK-producing strain was isolated from cow milk and identified. To enhance the yield of NK, effect of various parameters such as pH, temperature, carbon source, nitrogen source and inoculum size were optimized. Strain improvement of P. aeruginosa CMSS was done by random UV-mutagenesis. Nattokinase was partially purified and the activity was determined by the casein digestion method, blood clot lysis and fibrin degradation assay. Based on morphological, biochemical and molecular characterization, the strain was confirmed as P. aeruginosa (GenBank accession number: JX112657), designated as P. aeruginosa CMSS. The optimum condition at pH 7 and temperature at 25˚C showed activity of NK as 1514 U mL(-1) and 1532 U mL(-1), respectively. Sucrose as the carbon source and shrimp shell powder (SSP) as the nitrogen source expressed NK activity of 1721 U mL(-1) and 2524 U mL(-1), respectively. At 1% inoculum size, the maximum rate of enzyme production was achieved with 2581 U mL(-1). The NK activity of the mutant strain UV60 was 4263 U mL(-1), indicating a two-fold increase in activity compared to the wild strain (2581 UmL(-1)). Nattokinase produced from mutant strain P. aeruginosa CMSS UV60 showed 94% blood clot lysis at ten minutes. The degradation of fibrin clot by the produced NK was observed after two hours of incubation. Sodium dodecyl sulfate polyacrylamide gel

  6. A low-level diode laser therapy reduces the lipopolysaccharide (LPS)-induced periodontal ligament cell inflammation

    International Nuclear Information System (INIS)

    Huang, T H; Chen, C C; Liu, S L; Lu, Y C; Kao, C T

    2014-01-01

    The purpose of this study was to investigate the cytologic effects of inflammatory periodontal ligament cells in vitro after low-level laser therapy. Human periodontal ligament cells were cultured, exposed to lipopolysaccharide and subjected to low-level laser treatment of 5 J cm −2 or 10 J cm −2 using a 920 nm diode laser. A periodontal ligament cell attachment was observed under a microscope, and the cell viability was quantified by a mitochondrial colorimetric assay. Lipopolysaccharide-treated periodontal ligament cells were irradiated with the low-level laser, and the expression levels of several inflammatory markers, iNOS, TNF-α and IL-1, and pErk kinase, were analyzed by reverse transcription polymerase chain reaction and western blot. The data were collected and analyzed by one-way analysis of variance; p < 0.05 indicated a statistically significant difference. The low-level laser treatment of periodontal ligament cells increased their ability to attach and survive. After irradiation, the expression levels of iNOS, TNF-α and IL-1 in lipopolysaccharide-exposed periodontal ligament cells decreased over time (p < 0.05). In periodontal ligament cells, low-level diode laser treatment increased the cells’ proliferative ability and decreased the expression of the examined inflammatory mediators. (letters)

  7. Lipopolysaccharide and Lipoteichoic Acid Virulence Deactivation by Stannous Fluoride.

    Science.gov (United States)

    Haught, Chris; Xie, Sancai; Circello, Ben; Tansky, Cheryl S; Khambe, Deepa; Klukowska, Malgorzata; Huggins, Tom; White, Donald J

    2016-09-01

    Oral bacterial pathogens promote gingivitis and periodontal disease. Bacterial endotoxins, also known as lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs), are known to enhance bacterial pathogenicity through binding with Toll-like receptors (TLRs), a group of pattern recognition receptors critical to the activation of innate immunity, that are expressed on host cells. Both LPS and LTA contain lipophilic domains and anionic charges that may be susceptible to reactivity with stannous fluoride, a commonly used ingredient clinically proven for the treatment and prevention of gingivitis. This study examined the effects of stannous fluoride on Toll-like receptor activation in response to bacterially derived LPS and LTA in select cell lines and secretion of inflammatory cytokines from human primary peripheral monocytes likewise exposed to LPS. TLR4 and TLR2 transfected HEK293 cells and THP1-Dual™ cells were exposed to bacterial LPS and LTA in the presence of increasing concentrations of stannous fluoride. Gene expression was assessed by measurement of secreted embryonic alkaline phosphatase (SEAP) reporter gene for HEK293 cells and SEAP and luciferase for THP-1 cells. Cell viability was confirmed using PrestoBlue. Human primary monocytes were treated with LPS with various concentrations of supplemented stannous fluoride, and cytokine expression was directly measured. Stannous fluoride inhibited gene expression response of TLR4 and TLR2 in HEK293 cells and THP1-Dual™ cells in a dose response fashion, producing complete inhibition at micromolar concentrations. The addition of stannous fluoride suppressed production of TNF-a, IFN-g, IL12p70, IL10, IL-1b, IL2, and IL-6, and also increased secretion of Il-8 in dose response fashion. Viability assays confirmed no effects of LPS or stannous fluoride on viability of HEK293, THP-1, and primary human monocytes. These results support the potential for stannous fluoride to provide clinical gingivitis benefits by directly

  8. Crude petroleum-oil biodegradation efficiency of Bacillus subtilis and Pseudomonas aeruginosa strains isolated from a petroleum-oil contaminated soil from North-East India.

    Science.gov (United States)

    Das, Kishore; Mukherjee, Ashis K

    2007-05-01

    The efficiency of Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains isolated from a petroleum contaminated soil sample from North-East India was compared for the biodegradation of crude petroleum-oil hydrocarbons in soil and shake flask study. These bacterial strains could utilize crude petroleum-oil hydrocarbons as sole source of carbon and energy. Bioaugmentation of TPH contaminated microcosm with P. aeruginosa M and NM consortia and B. subtilis strain showed a significant reduction of TPH levels in treated soil as compared to control soil at the end of experiment (120 d). P. aeruginosa strains were more efficient than B. subtilis strain in reducing the TPH content from the medium. The plate count technique indicated expressive growth and biosurfactant production by exogenously seeded bacteria in crude petroleum-oil rich soil. The results showed that B. subtilis DM-04 and P. aeruginosa M and NM strains could be effective for in situ bioremediation.

  9. Enzyme-mediated quenching of the Pseudomonas quinolone signal (PQS promotes biofilm formation of Pseudomonas aeruginosa by increasing iron availability

    Directory of Open Access Journals (Sweden)

    Beatrix Tettmann

    2016-12-01

    Full Text Available The 2-alkyl-3-hydroxy-4(1H-quinolone 2,4-dioxygenase HodC was previously described to cleave the Pseudomonas quinolone signal, PQS, which is exclusively used in the complex quorum sensing (QS system of Pseudomonas aeruginosa, an opportunistic pathogen employing QS to regulate virulence and biofilm development. Degradation of PQS by exogenous addition of HodC to planktonic cells of P. aeruginosa attenuated production of virulence factors, and reduced virulence in planta. However, proteolytic cleavage reduced the efficacy of HodC. Here, we identified the secreted protease LasB of P. aeruginosa to be responsible for HodC degradation. In static biofilms of the P. aeruginosa PA14 lasB::Tn mutant, the catalytic activity of HodC led to an increase in viable biomass in newly formed but also in established biofilms, and reduced the expression of genes involved in iron metabolism and siderophore production, such as pvdS, pvdL, pvdA and pvdQ. This is likely due to an increase in the levels of bioavailable iron by degradation of PQS, which is able to sequester iron from the surrounding environment. Thus, HodC, despite its ability to quench the production of virulence factors, is contraindicated for combating P. aeruginosa biofilms.

  10. The effect of loss of O-antigen ligase on phagocytic susceptibility of motile and non-motile Pseudomonas aeruginosa.

    Science.gov (United States)

    Demirdjian, Sally; Schutz, Kristin; Wargo, Matthew J; Lam, Joseph S; Berwin, Brent

    2017-12-01

    The bacterial pathogen Pseudomonas aeruginosa undergoes adaptation and selection over the course of chronic respiratory tract infections which results in repeatedly-observed phenotypic changes that are proposed to enable its persistence. Two of the clinically significant P. aeruginosa phenotypic changes are loss of flagellar motility and modifications to LPS structure, including loss of O-antigen expression. The effect of loss of O-antigen, frequently described as conversion from smooth to rough LPS, and the combined effect of loss of motility and O-antigen on phagocytic susceptibility by immune cells remain unknown. To address this, we generated genetic deletion mutants of waaL, which encodes the O-antigen ligase responsible for linking O-antigen to lipid A-core oligosaccharide, in both motile and non-motile P. aeruginosa strains. With the use of these bacterial strains we provide the first demonstration that, despite a progressive selection for P. aeruginosa with rough LPS during chronic pulmonary infections, loss of the LPS O-antigen does not confer phagocytic resistance in vitro. However, use of the waaLmotABmotCD mutant revealed that loss of motility confers resistance to phagocytosis regardless of the smooth or rough LPS phenotype. These findings reveal how the O-antigen of P. aeruginosa can influence bacterial clearance during infection and expand our current knowledge about the impact of bacterial phenotypic changes during chronic infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Carbapenem-resistant and cephalosporin-susceptible: a worrisome phenotype among Pseudomonas aeruginosa clinical isolates in Brazil.

    Science.gov (United States)

    Campana, Eloiza Helena; Xavier, Danilo Elias; Petrolini, Fernanda Villas-Boas; Cordeiro-Moura, Jhonatha Rodrigo; Araujo, Maria Rita Elmor de; Gales, Ana Cristina

    The mechanisms involved in the uncommon resistance phenotype, carbapenem resistance and broad-spectrum cephalosporin susceptibility, were investigated in 25 Pseudomonas aeruginosa clinical isolates that exhibited this phenotype, which were recovered from three different hospitals located in São Paulo, Brazil. The antimicrobial susceptibility profile was determined by CLSI broth microdilution. β-lactamase-encoding genes were investigated by PCR followed by DNA sequencing. Carbapenem hydrolysis activity was investigated by spectrophotometer and MALDI-TOF assays. The mRNA transcription level of oprD was assessed by qRT-PCR and the outer membrane proteins profile was evaluated by SDS-PAGE. Genetic relationship among P. aeruginosa isolates was assessed by PFGE. Carbapenems hydrolysis was not detected by carbapenemase assay in the carbapenem-resistant and cephalosporin-susceptible P. aueruginosa clinical isolates. OprD decreased expression was observed in all P. aeruginosa isolates by qRT-PCR. The outer membrane protein profile by SDS-PAGE suggested a change in the expression of the 46kDa porin that could correspond to OprD porin. The isolates were clustered into 17 genotypes without predominance of a specific PFGE pattern. These results emphasize the involvement of multiple chromosomal mechanisms in carbapenem-resistance among clinical isolates of P. aeruginosa, alert for adaptation of P. aeruginosa clinical isolates under antimicrobial selective pressure and make aware of the emergence of an uncommon phenotype among P. aeruginosa clinical isolates. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  12. Intermittent fasting attenuates lipopolysaccharide-induced neuroinflammation and memory impairment.

    Science.gov (United States)

    Vasconcelos, Andrea R; Yshii, Lidia M; Viel, Tania A; Buck, Hudson S; Mattson, Mark P; Scavone, Cristoforo; Kawamoto, Elisa M

    2014-05-06

    Systemic bacterial infections often result in enduring cognitive impairment and are a risk factor for dementia. There are currently no effective treatments for infection-induced cognitive impairment. Previous studies have shown that intermittent fasting (IF) can increase the resistance of neurons to injury and disease by stimulating adaptive cellular stress responses. However, the impact of IF on the cognitive sequelae of systemic and brain inflammation is unknown. Rats on IF for 30 days received 1 mg/kg of lipopolysaccharide (LPS) or saline intravenously. Half of the rats were subjected to behavioral tests and the other half were euthanized two hours after LPS administration and the hippocampus was dissected and frozen for analyses. Here, we report that IF ameliorates cognitive deficits in a rat model of sepsis by a mechanism involving NF-κB activation, suppression of the expression of pro-inflammatory cytokines, and enhancement of neurotrophic support. Treatment of rats with LPS resulted in deficits in cognitive performance in the Barnes maze and inhibitory avoidance tests, without changing locomotor activity, that were ameliorated in rats that had been maintained on the IF diet. IF also resulted in reduced levels of mRNAs encoding the LPS receptor TLR4 and inducible nitric oxide synthase (iNOS) in the hippocampus. Moreover, IF prevented LPS-induced elevation of IL-1α, IL-1β and TNF-α levels, and prevented the LPS-induced reduction of BDNF levels in the hippocampus. IF also significantly attenuated LPS-induced elevations of serum IL-1β, IFN-γ, RANTES, TNF-α and IL-6 levels. Taken together, our results suggest that IF induces adaptive responses in the brain and periphery that can suppress inflammation and preserve cognitive function in an animal model of systemic bacterial infection.

  13. The metabolically active subpopulation in Pseudomonas aeruginosa biofilms survives exposure to membrane-targeting antimicrobials via distinct molecular mechanisms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Pamp, Sünje Johanna; Nilsson, Martin

    2012-01-01

    encoding lipopolysaccharide modification enzymes, as well as on the mexAB-oprM, mexCD-oprJ, and muxABC-opmB genes encoding antimicrobial efflux pumps, but does not depend on the mexPQ-opmE efflux pump genes. Development of chlorhexidine-tolerant subpopulations was found to depend on the mexCD-oprJ genes......, but does not depend on the pmr, mexAB-oprM, mexPQ-opmE, or muxABC-opmB genes. Tolerance to SDS and EDTA in P. aeruginosa biofilms is linked to metabolically active cells, but does not depend on the pmr, mexAB, mexCD, mexPQ, or muxABC genes. Our data suggest that the active subpopulation in P. aeruginosa......-targeting compounds colistin, EDTA, SDS, and chlorhexidine resulted in the same spatial distribution of live and dead bacteria, we investigated whether tolerance to these compounds originated from the same molecular mechanisms. Development of colistin-tolerant subpopulations was found to depend on the pmr genes...

  14. Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Domenech

    2011-01-01

    Full Text Available Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP or phosphorylcholine (Pcho. The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs: one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure.

  15. Murine P-glycoprotein deficiency alters intestinal injury repair and blunts lipopolysaccharide-induced radioprotection.

    Science.gov (United States)

    Staley, Elizabeth M; Yarbrough, Vanisha R; Schoeb, Trenton R; Daft, Joseph G; Tanner, Scott M; Steverson, Dennis; Lorenz, Robin G

    2012-09-01

    P-glycoprotein (P-gp) has been reported to increase stem cell proliferation and regulate apoptosis. Absence of P-gp results in decreased repair of intestinal epithelial cells after chemical injury. To further explore the mechanisms involved in the effects of P-gp on intestinal injury and repair, we used the well-characterized radiation injury model. In this model, injury repair is mediated by production of prostaglandins (PGE(2)) and lipopolysaccharide (LPS) has been shown to confer radioprotection. B6.mdr1a(-/-) mice and wild-type controls were subjected to 12 Gy total body X-ray irradiation and surviving crypts in the proximal jejunum and distal colon were evaluated 3.5 days after irradiation. B6.mdr1a(-/-) mice exhibited normal baseline stem cell proliferation and COX dependent crypt regeneration after irradiation. However, radiation induced apoptosis was increased and LPS-induced radioprotection was blunted in the C57BL6.mdr1a(-/-) distal colon, compared to B6 wild-type controls. The LPS treatment induced gene expression of the radioprotective cytokine IL-1α, in B6 wild-type controls but not in B6.mdr1a(-/-) animals. Lipopolysaccharid-induced radioprotection was absent in IL-1R1(-/-) animals, indicating a role for IL-1α in radioprotection, and demonstrating that P-gp deficiency interferes with IL-1α gene expression in response to systemic exposure to LPS.

  16. FpvA receptor involvement in pyoverdine biosynthesis in Pseudomonas aeruginosa.

    Science.gov (United States)

    Shen, Jiangsheng; Meldrum, Allison; Poole, Keith

    2002-06-01

    Alignment of the Pseudomonas aeruginosa ferric pyoverdine receptor, FpvA, with similar ferric-siderophore receptors revealed that the mature protein carries an extension of ca. 70 amino acids at its N terminus, an extension shared by the ferric pseudobactin receptors of P. putida. Deletion of fpvA from the chromosome of P. aeruginosa reduced pyoverdine production in this organism, as a result of a decline in expression of genes (e.g., pvdD) associated with the biosynthesis of the pyoverdine peptide moiety. Wild-type fpvA restored pvd expression in the mutant, thereby complementing its pyoverdine deficiency, although a deletion derivative of fpvA encoding a receptor lacking the N terminus of the mature protein did not. The truncated receptor was, however, functional in pyoverdine-mediated iron uptake, as evidenced by its ability to promote pyoverdine-dependent growth in an iron-restricted medium. These data are consistent with the idea that the N-terminal extension plays a role in FpvA-mediated pyoverdine biosynthesis in P. aeruginosa.

  17. Pseudomonas Aeruginosa: interactions with organisms in the environment and cells of the immune defence

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena

    2008-01-01

    , which emphasises the urgent need for development of novel strategies that will help us to defeat this pathogen. P. aeruginosa biofilm cells display a multicellular-like coordinated behaviour and control expression of virulence factors, elements involved in biofilm development and immunomodulating...... factors by means of signal molecule mediated communication, known as quorum sensing. This thesis explores a strategy which aims to counteract P. aeruginosa virulence and pathogenicity by impeding its cell-to-cell communication. A treatment regime, which focuses on targeting bacterial communication instead......; two quorum sensing signal molecules; the Pseudomonas Quinolone Signal and N-3-oxododecanoyl L-homoserine lactone exhibit the ability to modulate activities of the immune defence in addition to functioning as quorum sensing mediators. The two signal molecules impair activities of immune cells crucial...

  18. Differentiation and distribution of colistin- and sodium dodecyl sulfate-tolerant cells in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Klausen, M; Ernst, RK

    2007-01-01

    During Pseudomonas aeruginosa flow cell biofilm development, the cell population differentiates into a nonmotile subpopulation which forms microcolonies and a migrating subpopulation which eventually colonizes the top of the microcolonies, resulting in the development of mushroom-shaped multicell......During Pseudomonas aeruginosa flow cell biofilm development, the cell population differentiates into a nonmotile subpopulation which forms microcolonies and a migrating subpopulation which eventually colonizes the top of the microcolonies, resulting in the development of mushroom......-targeting antibacterial agents. All biofilm-associated cells were sensitive to the antibacterial agents when tested in standard plate assays. A mutation eliminating the production of type IV pili, and hence surface-associated motility, prevented the formation of regular mushroom-shaped structures in the flow cell...... that only the cap-forming subpopulation in biofilms treated with colistin expresses the pmr operon. These results suggest that increased antibiotic tolerance in biofilms may be a consequence of differentiation into distinct subpopulations with different phenotypic properties....

  19. DMPD: CD14 and other recognition molecules for lipopolysaccharide: a review. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 7542643 CD14 and other recognition molecules for lipopolysaccharide: a review. Kiel...her recognition molecules for lipopolysaccharide: a review. PubmedID 7542643 Title CD14 and other recognitio...n molecules for lipopolysaccharide: a review. Authors Kielian TL, Blecha F. Publi

  20. DMPD: Lipopolysaccharide-binding molecules: transporters, blockers and sensors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15241548 Lipopolysaccharide-binding molecules: transporters, blockers and sensors. ...binding molecules: transporters, blockers and sensors. PubmedID 15241548 Title Lipopolysaccharide-binding molecules: transport...Chaby R. Cell Mol Life Sci. 2004 Jul;61(14):1697-713. (.png) (.svg) (.html) (.csml) Show Lipopolysaccharide-

  1. Chromosomal organization and segregation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Isabelle Vallet-Gely

    2013-05-01

    Full Text Available The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed.

  2. The Versatile Mutational Resistome of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Carla López-Causapé

    2018-04-01

    Full Text Available One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P. aeruginosa antibiotic resistance, thus motivating this review. Indeed, the analysis of the WGS mutational resistome has proven to be useful for understanding the evolutionary dynamics of classical resistance pathways and to describe new mechanisms for the majority of antipseudomonal classes, including β-lactams, aminoglycosides, fluoroquinolones, or polymixins. Beyond addressing a relevant scientific question, the analysis of the P. aeruginosa mutational resistome is expected to be useful, together with the analysis of the horizontally-acquired resistance determinants, for establishing the antibiotic resistance genotype, which should correlate with the antibiotic resistance phenotype and as such, it should be useful for the design of therapeutic strategies and for monitoring the efficacy of administered antibiotic treatments. However, further experimental research and new bioinformatics tools are still needed to overcome the interpretation limitations imposed by the complex interactions (including those leading to collateral resistance or susceptibility between the 100s of genes involved in the mutational resistome, as well as the frequent difficulties for differentiating relevant mutations from simple natural polymorphisms.

  3. The Versatile Mutational Resistome of Pseudomonas aeruginosa.

    Science.gov (United States)

    López-Causapé, Carla; Cabot, Gabriel; Del Barrio-Tofiño, Ester; Oliver, Antonio

    2018-01-01

    One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS) data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P. aeruginosa antibiotic resistance, thus motivating this review. Indeed, the analysis of the WGS mutational resistome has proven to be useful for understanding the evolutionary dynamics of classical resistance pathways and to describe new mechanisms for the majority of antipseudomonal classes, including β-lactams, aminoglycosides, fluoroquinolones, or polymixins. Beyond addressing a relevant scientific question, the analysis of the P. aeruginosa mutational resistome is expected to be useful, together with the analysis of the horizontally-acquired resistance determinants, for establishing the antibiotic resistance genotype, which should correlate with the antibiotic resistance phenotype and as such, it should be useful for the design of therapeutic strategies and for monitoring the efficacy of administered antibiotic treatments. However, further experimental research and new bioinformatics tools are still needed to overcome the interpretation limitations imposed by the complex interactions (including those leading to collateral resistance or susceptibility) between the 100s of genes involved in the mutational resistome, as well as the frequent difficulties for differentiating relevant mutations from simple natural polymorphisms.

  4. Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats

    DEFF Research Database (Denmark)

    Johansen, H K; Espersen, F; Pedersen, S S

    1993-01-01

    We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes...

  5. Pseudomonas aeruginosa burn wound infection in a dedicated ...

    African Journals Online (AJOL)

    Background. Pseudomonas aeruginosa infection is a major cause of morbidity in burns patients. There is a paucity of publications dealing with this infection in the paediatric population. We describe the incidence, microbiology and impact of P. aeruginosa infection in a dedicated paediatric burns unit. Methods.

  6. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

    Pseudomonas aeruginosa causes infection in all parts of the human body. The bacterium is naturally resistant to a wide range of antibiotics. In addition to resistance mechanisms such as efflux pumps, the ability to form aggregates, known as biofilm, further reduces Pseudomonas aeruginosa...

  7. Ap-PCR typing of carbapenem sensitive Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    In this study the antibiotic susceptibility of 51 P. aeruginosa strains isolated from clinical samples were detected by the disc diffusion test. The susceptibility of P. aeruginosa strains were found as respectively 55% amicacin, 43% aztreonam, 75% netilmycin, 68% sefepim, 73% ceftazidim, 76% ciproflaxacin, 37% gentamicin, ...

  8. A Carbenicillin R Factor from Pseudomonas aeruginosa | van ...

    African Journals Online (AJOL)

    Of 64 carbenicillin-resistant Pseudomonas aeruginosa strains 40 transferred this resistance to Escherichia coli. R factor RP-638 isolated from Ps. aeruginosa strain 638 conferred resistance to ampicillin, carbenicillin, kanamycin, neomycin and tetracycline. This R factor was transferred at frequencies 01 10-7 to 10-4 between ...

  9. Inflammatory Response to Lipopolysaccharide on the Ocular Surface in a Murine Dry Eye Model.

    Science.gov (United States)

    Simmons, Ken T; Xiao, Yangyan; Pflugfelder, Stephen C; de Paiva, Cintia S

    2016-05-01

    Toll-like receptor 4 (TLR4) alerts cells to the presence of bacteria by initiating an inflammatory response. We hypothesize that disruption of the ocular surface barrier in dry eye enhances TLR4 signaling. This study determined whether dry eye enhances expression of inflammatory mediators in response to topically applied TLR4 ligand. A single dose of lipopolysaccharide (LPS) or vehicle (endotoxin-free water) was applied to the cornea of nonstressed (NS) mice or mice subjected to 5 days of desiccating stress (DS). After 4 hours, corneal epithelium and conjunctiva were extracted to analyze expression of inflammatory mediators via PCR. Protein expression was confirmed by immunobead assay and immunostaining. Topically applied LPS increased expression of inflammatory mediators IL-1β, CXCL10, IL-12a, and IFN-γ in the conjunctiva, and IL-1β and CXCL10 in the cornea of NS mice compared to that in untreated controls. LPS in DS mice produced 3-fold increased expression of IL-1β in cornea and 2-fold increased expression in IL-12a in conjunctiva compared to that in LPS-treated control mice. LPS increased expression of inflammatory cytokines on the ocular surface. This expression was further increased in dry eye, which suggests that epithelial barrier disruption enhances exposure of LPS to TLR4+ cells and that the inflammatory response to endotoxin-producing commensal or pathogenic bacteria may be more severe in dry eye disease.

  10. Post-secretional activation of Protease IV by quorum sensing in Pseudomonas aeruginosa

    OpenAIRE

    Oh, Jungmin; Li, Xi-Hui; Kim, Soo-Kyong; Lee, Joon-Hee

    2017-01-01

    Protease IV (PIV), a key virulence factor of Pseudomonas aeruginosa is a secreted lysyl-endopeptidase whose expression is induced by quorum sensing (QS). We found that PIV expressed in QS mutant has severe reduction of activity in culture supernatant (CS), even though it is overexpressed to high level. PIV purified from the QS mutant (M-PIV) had much lower activity than the PIV purified from wild type (P-PIV). We found that the propeptide cleaved from prepro-PIV was co-purified with M-PIV, bu...

  11. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-01-01

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs

  12. Targeting quorum sensing in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Bjarnsholt, Thomas; Jensen, Peter Østrup

    2013-01-01

    Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication...... alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic...

  13. Extracellular toxins of pseudomonas aeruginosa. Pt. 4

    International Nuclear Information System (INIS)

    Obernesser, H.J.; Doering, G.

    1982-01-01

    A sensitive and specific solid phase radioimmunoassay (RIA) for detection of the elastase (Ela) of Pseudomonas aeruginosa (PA) was developed and the RIA was used to assay 10 PA strains of various origin and serotype. A great strain variability of Ela production was found which different from 94.1 to 0.1 μg per ml of culture supernatant fluid (CSF). The Ela and alkaline protease (AP) concentrations were converted to proteolytic activity and combined. The sum of the calculated enzymatic values of Ela and AP correlated well with the experimentally determined values of total proteolytic activity of the CSF. (orig.) [de

  14. Inhibition of Nitric Oxide and Prostaglandin E 2 Expression by ...

    African Journals Online (AJOL)

    Inhibition of Nitric Oxide and Prostaglandin E 2 Expression by Methanol Extract of Polyopes affinis in Lipopolysaccharide-stimulated BV2 Microglial Cells through Suppression of Akt-dependent NF-kB Activity and MAPK Pathway.

  15. A laminar flow model of aerosol survival of epidemic and non-epidemic strains of Pseudomonas aeruginosa isolated from people with cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Denton Miles

    2008-06-01

    Full Text Available Abstract Background Cystic fibrosis (CF is an inherited multi-system disorder characterised by chronic airway infection with pathogens such as Pseudomonas aeruginosa. Acquisition of P. aeruginosa by patients with CF is usually from the environment, but recent studies have demonstrated patient to patient transmission of certain epidemic strains, possibly via an airborne route. This study was designed to examine the survival of P. aeruginosa within artificially generated aerosols. Results Survival was effected by the solution used for aerosol generation. Within the aerosols it was adversely affected by an increase in air temperature. Both epidemic and non-epidemic strains of P. aeruginosa were able to survive within the aerosols, but strains expressing a mucoid phenotype had a survival advantage. Conclusion This would suggest that segregating individuals free of P. aeruginosa from those with chronic P. aeruginosa infection who are more likely to be infected with mucoid strains may help reduce the risk of cross-infection. Environmental factors also appear to influence bacterial survival. Warming and drying the air within clinical areas and avoidance of humidification devices may also be beneficial in reducing the risk of cross-infection.

  16. Introduction of Pseudomonas aeruginosa into a Hospital via Vegetables

    Science.gov (United States)

    Kominos, Spyros D.; Copeland, Charles E.; Grosiak, Barbara; Postic, Bosko

    1972-01-01

    Pseudomonas aeruginosa was isolated from tomatoes, radishes, celery, carrots, endive, cabbage, cucumbers, onions, and lettuce obtained from the kitchen of a general hospital, with tomatoes yielding both highest frequencies of isolation and highest counts. Presence of P. aeruginosa on the hands of kitchen personnel and cutting boards and knives which they used suggests acquisition of the organism through contact with these vegetables. It is estimated that a patient consuming an average portion of tomato salad might ingest as many as 5 × 103 colony-forming units of P. aeruginosa. Pyocine types of P. aeruginosa isolated from clinical specimens were frequently identical to those recovered from vegetables, thus implicating tomatoes and other vegetables as an important source and vehicle by which P. aeruginosa colonizes the intestinal tract of patients. PMID:4628795

  17. Occurrence of pseudomonas aeruginosa in post-operative wound infection

    International Nuclear Information System (INIS)

    Oguntibeju, O.O.; Nwobu, R.A.U.

    2004-01-01

    Objective: To determine the prevalence of Pseudomonas aeruginosa in post-operative wound infection. Results: Out of the 60 bacterial isolates found in post-operative wound infection, 20 (33.3%) were Pseudomonas aeruginosa, followed by Staphylococcus aureus 13(21.7%), Klebsiella species 10(16.7%), Escherichia coli 7(11.7%), Atypical coliform 4(6.7%), Proteus species 4(6.7%), Streptococcus pyogenes 1(1.7%) and Enterococcus faecalis 1(1.7%) in the order. Pseudomonas aeruginosa infections was higher in female than male, ratio 3:2 and was found more among young and elderly debilitated patients. The in vitro sensitivity pattern of 20 isolates of Pseudomonas aeruginosa showed colistin (100%), gentamicin (75%), streptomycin (30%), and tetracycline (10%). Conclusion: The role of Pseudomonas aeruginosa as an agent of nosocomial infection is re-emphasised. (author)

  18. Peptide-assembled graphene oxide as fluorescent turn-on sensor for ultrasensitive Lipopolysaccharide (Endotoxin detection

    Directory of Open Access Journals (Sweden)

    Seng Koon Lim

    2014-06-01

    Full Text Available Introduction: Lipopolysaccharide (LPS, or endotoxin, a major component in the outer cell membrane of Gram-negative bacteria is a very powerful and toxic inflammatory stimulator, resulting in sepsis or septic shock, a significant medical problem affecting about 700 000 patients and causing 250 000 casualties annually in the United States itself. The detection of LPS is highly importance. However, the currently used enzymatic limulus amebocyte lysate assay is highly susceptible to changes in temperature and pH, interference factors, and requires cumbersome sample preparation. A more cost-effective, sensitive and robust detection method is needed. Objective: To design and develop biosensor for LPS detection by assembling a LPS-binding peptide (as LPS receptor with graphene oxide (GO, as fluorescence quencher. Methods: GO was synthesized using a modified Hummer’s method. A synthetic LPS-binding peptide was designed, fluorescent labelled, and assembled with GO in PBS buffer solution. The fluorescence recovery of the peptide-GO was measured upon addition of LPS from Gram negative bacteria: E. coli, K. pneumoniae, Samonella Thyphosa, P. aeruginosa, as well as living pathogenic bacteria. Specificity tests were conducted with various biological molecules to evaluate the sensing performance. Results & Discussion: Specific binding of LPS with peptide release the peptides from GO, resulting in fluorescence recovery, allowing ultrasensitive detection of LPS with the limit of detection of 130 pM, the most sensitive synthetic LPS sensors to-date. The LPS sensor is highly selective to LPS than other biological species. Conclusion: We developed a peptide-GO assembled fluorescence sensor for ultrasensitive and specific LPS/endotoxin detection. This is the most sensitive synthetic LPS sensor reported in the world.

  19. Lipopolysaccharide-induced Pulpitis Up-regulates TRPV1 in Trigeminal Ganglia

    Science.gov (United States)

    Chung, M.-K.; Lee, J.; Duraes, G.; Ro, J.Y.

    2011-01-01

    Tooth pain often accompanies pulpitis. Accumulation of lipopolysaccharides (LPS), a product of Gram-negative bacteria, is associated with painful clinical symptoms. However, the mechanisms underlying LPS-induced tooth pain are not clearly understood. TRPV1 is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and hyperalgesia under inflammation or injury. Although TRPV1 is expressed in pulpal afferents, it is not known whether the application of LPS to teeth modulates TRPV1 in trigeminal nociceptors. By assessing the levels of protein and transcript of TRPV1 in mouse trigeminal ganglia, we demonstrate that dentinal application of LPS increases the expression of TRPV1. Our results suggest that the up-regulation of TRPV1 in trigeminal nociceptors following bacterial infection could contribute to hyperalgesia under pulpitis conditions. PMID:21712529

  20. The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa.

    Science.gov (United States)

    Dong, Yi-Hu; Zhang, Xi-Fen; Zhang, Lian-Hui

    2013-02-01

    The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA-binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT-PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine-tune this virulence mechanism in response to environmental changes and nutrient sources. © 2012 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  1. Risk factors for and role of OprD protein in increasing minimal inhibitory concentrations of carbapenems in clinical isolates of Pseudomonas aeruginosa.

    Science.gov (United States)

    Hirabayashi, Aki; Kato, Daizo; Tomita, Yuka; Iguchi, Mitsutaka; Yamada, Keiko; Kouyama, Yuichi; Morioka, Hiroshi; Tetsuka, Nobuyuki; Yagi, Tetsuya

    2017-11-01

    This study examined the risk factors for, and molecular mechanisms underlying, the increase in carbapenem minimum inhibitory concentrations (MICs) in clinical isolates of Pseudomonas aeruginosa. Consecutive clinical isolates of P. aeruginosa were collected. The MicroScan WalkAway system detected more than fourfold increases in the MICs of carbapenems in P. aeruginosa isolates serially recovered from some patients during their clinical course. The clinical risk factors associated with this increase were examined by multiple logistic regression analysis. Western blot analysis and nucleotide sequencing of the oprD gene of 19 clonally related and paired P. aeruginosa isolates from the same patients were undertaken to examine the mechanisms underlying the increase in MICs. The results showed that prior use of carbapenems (OR, 2.799; 95 % CI, 1.088-7.200; P=0.033) and the use of ventilators or tracheostomies (OR, 2.648; 95 % CI, 1.051-6.671; P=0.039) were risk factors for increased carbapenem MICs. Analysis of the underlying mechanisms revealed that loss of functional OprD protein due to mutation of the oprD gene tended to occur in P. aeruginosa isolates with imipenem MICs of more than 8 µg ml -1 ; a reduction in OprD expression was observed in P. aeruginosa isolates with imipenem MICs of 4 or 8 µg ml -1 . This difference in the resistance mechanism was not correlated with the MICs of meropenem. This difference in the resistance mechanism of P. aeruginosa indicates a critical breakpoint at an imipenem MIC of 8 µg ml -1 , in accordance with EUCAST criteria. Reducing carbapenem use will prevent P. aeruginosa clinical isolates from developing resistance to carbapenems.

  2. Suaeda japonica Makino Attenuates Lipopolysaccharide- Induced ...

    African Journals Online (AJOL)

    HP

    Tropical Journal of Pharmaceutical Research June 2013; 12 (3): 351-356 ... expression and production of inflammatory mediators determined by Western blot analysis. Results: SJE significantly ..... This work was supported by Business for.

  3. Blue light treatment of Pseudomonas aeruginosa: Strong bactericidal activity, synergism with antibiotics and inactivation of virulence factors.

    Science.gov (United States)

    Fila, Grzegorz; Kawiak, Anna; Grinholc, Mariusz Stanislaw

    2017-08-18

    Pseudomonas aeruginosa is among the most common pathogens responsible for both acute and chronic infections of high incidence and severity. Additionally, P. aeruginosa resistance to conventional antimicrobials has increased rapidly over the past decade. Therefore, it is crucial to explore new therapeutic options, particularly options that specifically target the pathogenic mechanisms of this microbe. The ability of a pathogenic bacterium to cause disease is dependent upon the production of agents termed 'virulence factors', and approaches to mitigate these agents have gained increasing attention as new antibacterial strategies. Although blue light irradiation is a promising alternative approach, only limited and preliminary studies have described its effect on virulence factors. The current study aimed to investigate the effects of lethal and sub-lethal doses of blue light treatment (BLT) on P. aeruginosa virulence factors. We analyzed the inhibitory effects of blue light irradiation on the production/activity of several virulence factors. Lethal BLT inhibited the activity of pyocyanin, staphylolysin, pseudolysin and other proteases, but sub-lethal BLT did not affect the production/expression of proteases, phospholipases, and flagella- or type IV pili-associated motility. Moreover, a eukaryotic cytotoxicity test confirmed the decreased toxicity of blue light-treated extracellular P. aeruginosa fractions. Finally, the increased antimicrobial susceptibility of P. aeruginosa treated with sequential doses of sub-lethal BLT was demonstrated with a checkerboard test. Thus, this work provides evidence-based proof of the susceptibility of drug-resistant P. aeruginosa to BLT-mediated killing, accompanied by virulence factor reduction, and describes the synergy between antibiotics and sub-lethal BLT.

  4. Inhibition of biofilm formation, quorum sensing and infection in Pseudomonas aeruginosa by natural products-inspired organosulfur compounds.

    Directory of Open Access Journals (Sweden)

    Nathaniel C Cady

    Full Text Available Using a microplate-based screening assay, the effects on Pseudomonas aeruginosa PAO1 biofilm formation of several S-substituted cysteine sulfoxides and their corresponding disulfide derivatives were evaluated. From our library of compounds, S-phenyl-L-cysteine sulfoxide and its breakdown product, diphenyl disulfide, significantly reduced the amount of biofilm formation by P. aeruginosa at levels equivalent to the active concentration of 4-nitropyridine-N-oxide (NPO (1 mM. Unlike NPO, which is an established inhibitor of bacterial biofilms, our active compounds did not reduce planktonic cell growth and only affected biofilm formation. When used in a Drosophila-based infection model, both S-phenyl-L-cysteine sulfoxide and diphenyl disulfide significantly reduced the P. aeruginosa recovered 18 h post infection (relative to the control, and were non-lethal to the fly hosts. The possibility that the observed biofilm inhibitory effects were related to quorum sensing inhibition (QSI was investigated using Escherichia coli-based reporters expressing P. aeruginosa lasR or rhIR response proteins, as well as an endogenous P. aeruginosa reporter from the lasI/lasR QS system. Inhibition of quorum sensing by S-phenyl-L-cysteine sulfoxide was observed in all of the reporter systems tested, whereas diphenyl disulfide did not exhibit QSI in either of the E. coli reporters, and showed very limited inhibition in the P. aeruginosa reporter. Since both compounds inhibit biofilm formation but do not show similar QSI activity, it is concluded that they may be functioning by different pathways. The hypothesis that biofilm inhibition by the two active compounds discovered in this work occurs through QSI is discussed.

  5. EXPRESS

    International Nuclear Information System (INIS)

    Ancelin, C.; Le, P.; DeSaint-Quentin, S.; Villatte, N.

    1987-01-01

    This paper presents EXPRESS, an expert system developed for the automation of reliability studies. The first part consists in the description of the method for static thermohydraulic systems. In this step, the authors define the knowledge representation based on the two inference engines - ALOUETTE and LCR developed by EDF. They explain all the process to construct a fault tree from a topological and functional description of the system. Numerous examples are exhibited in illustration of the method. This is followed by the lessons derived from the studies performed on some safety systems of the PALUEL nuclear plant. The development of the same approach for electric power systems is described, insisting on the difference resulting from the sequential nature of these systems. Finally, they show the main advantages identified during the studies

  6. Lipopolysaccharide contamination in intradermal DNA vaccination : toxic impurity or adjuvant?

    NARCIS (Netherlands)

    Berg, J.H. van den; Quaak, S.G.L.; Beijnen, J.H.; Hennink, W.E.; Storm, G.; Schumacher, T.N.; Haanen, J.B.A.G.; Nuijen, B.

    Purpose: Lipopolysaccharides (LPS) are known both as potential adjuvants for vaccines and as toxic impurity in pharmaceutical preparations. The aim of this study was to assess the role of LPS in intradermal DNA vaccination administered by DNA tattooing. Method: Micewere vaccinated with a model DNA

  7. Allicin Protects against Lipopolysaccharide-Induced Acute Lung ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of allicin, an active component of garlic, on lipopolysaccharide (LPS)- induced acute lung injury. Methods: Wistar rats were subjected to LPS intravenous injection with or without allicin treatment to induce acute lung injury (ALI) model. Also, A549 cells were stimulated with LPS in the ...

  8. Lipopolysaccharide: a Link between Periodontitis and Cardiometabolic Disorders

    OpenAIRE

    Kallio, Elisa

    2014-01-01

    Periodontitis is characterized by an inflammatory response to bacterial infection in the supporting tissues of the teeth. The disease manifests with gingival swelling and bleeding, increased periodontal pocket depth, and alveolar bone loss. Intact bacteria or bacterial products, including lipopolysaccharide (LPS), may enter the bloodstream through inflamed periodontal tissue or via saliva. Bacterial dissemination, further potentiated by gastrointestinal microbiota, may result in endotoxemia a...

  9. Lipopolysaccharide recognition, internalisation, signalling and other cellular effects

    NARCIS (Netherlands)

    Diks, S. H.; van Deventer, S. J.; Peppelenbosch, M. P.

    2001-01-01

    Despite the importance of bacterial lipopolysaccharide (LPS) in infection and inflammation, many aspects of LPS action remain poorly understood. Especially, the mechanisms by which cells recognise and react to endotoxins or endotoxin-containing particles and how cellular responses are translated

  10. Immunological properties of meningococcal lipopolysaccharide from serogroups A, B & C

    DEFF Research Database (Denmark)

    Jensen, T J; Kharazmi, A; Shand, G

    1996-01-01

    The aim of the study was to measure and compare the oxidative burst, chemotaxis and cytokine production of human white blood cells, stimulated with meningococcal lipopolysaccharides (LPS) extracted from three different serogroups (A, B and C) of Neisseria meningitidis, and to evaluate whether...

  11. Pseudomonas aeruginosa ventilator-associated pneumonia management

    Directory of Open Access Journals (Sweden)

    Ramírez-Estrada S

    2016-01-01

    Full Text Available Sergio Ramírez-Estrada,1 Bárbara Borgatta,1,2 Jordi Rello3,4 1Critical Care Department, Vall d'Hebron University Hospital, 2CRIPS, Vall d'Hebron Institute of Research (VHIR, 3Department of Medicine, Universitat Autònoma de Barcelona (UAB, Barcelona, 4Centro de Investigación Biomédica en Red Enfermedad Respiratoria – CIBERES, Madrid, Spain Abstract: Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising. Keywords: multidrug-resistant, ICU, new-antibiotics, adjunctive-therapies, care-bundles

  12. Biotransformation of myrcene by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hashemi Elham

    2011-05-01

    Full Text Available Abstract Background Dihydrolinalool and terpineol are sources of fragrances that provide a unique volatile terpenoid alcohol of low toxicity and thus are widely used in the perfumery industry, in folk medicine, and in aromatherapy. They are important chemical constituents of the essential oil of many plants. Previous studies have concerned the biotransformation of limonene by Pseudomonas putida. The objective of this research was to study biotransformation of myrcene by Pseudomonas aeruginosa. The culture preparation was done using such variables as different microbial methods and incubation periods to obtain maximum cells of P. aeruginosa for myrcene biotransformation. Results It was found that myrcene was converted to dihydrolinalool and 2,6-dimethyloctane in high percentages. The biotransformation products were identified by Fourier-transform infrared spectroscopy (FT-IR, ultraviolet (UV analysis, gas chromatography (GC, and gas chromatography-mass spectroscopy (GC-MS. Comparison of the different incubation times showed that 3 days was more effective, the major products being 2,6-dimethyloctane (90.0% and α-terpineol (7.7% and comprising 97.7%. In contrast, the main compounds derived for an incubation time of 1.5 days were dihydrolinalool (79.5% and 2,6-dimethyloctane (9.3%, with a total yield of 88.8%.

  13. Thrombospondin-1 production is enhanced by Porphyromonas gingivalis lipopolysaccharide in THP-1 cells.

    Directory of Open Access Journals (Sweden)

    Misa Gokyu

    Full Text Available Periodontitis is a chronic inflammatory disease caused by gram-negative anaerobic bacteria. Monocytes and macrophages stimulated by periodontopathic bacteria induce inflammatory mediators that cause tooth-supporting structure destruction and alveolar bone resorption. In this study, using a DNA microarray, we identified the enhanced gene expression of thrombospondin-1 (TSP-1 in human monocytic cells stimulated by Porphyromonas gingivalis lipopolysaccharide (LPS. TSP-1 is a multifunctional extracellular matrix protein that is upregulated during the inflammatory process. Recent studies have suggested that TSP-1 is associated with rheumatoid arthritis, diabetes mellitus, and osteoclastogenesis. TSP-1 is secreted from neutrophils, monocytes, and macrophages, which mediate immune responses at inflammatory regions. However, TSP-1 expression in periodontitis and the mechanisms underlying TSP-1 expression in human monocytic cells remain unknown. Here using real-time RT-PCR, we demonstrated that TSP-1 mRNA expression level was significantly upregulated in inflamed periodontitis gingival tissues and in P. gingivalis LPS-stimulated human monocytic cell line THP-1 cells. TSP-1 was expressed via Toll-like receptor (TLR 2 and TLR4 pathways. In P. gingivalis LPS stimulation, TSP-1 expression was dependent upon TLR2 through the activation of NF-κB signaling. Furthermore, IL-17F synergistically enhanced P. gingivalis LPS-induced TSP-1 production. These results suggest that modulation of TSP-1 expression by P. gingivalis plays an important role in the progression and chronicity of periodontitis. It may also contribute a new target molecule for periodontal therapy.

  14. Electromagnetic Radiation Disturbed the Photosynthesis of Microcystis aeruginosa at the Proteomics Level.

    Science.gov (United States)

    Tang, Chao; Yang, Chuanjun; Yu, Hui; Tian, Shen; Huang, Xiaomei; Wang, Weiyi; Cai, Peng

    2018-01-11

    Photosynthesis of Microcystis aeruginosa under Electromagnetic Radiation (1.8 GHz, 40 V/m) was studied by using the proteomics. A total of 30 differentially expressed proteins, including 15 up-regulated and 15 down-regulated proteins, were obtained in this study. The differentially expressed proteins were significantly enriched in the photosynthesis pathway, in which the protein expression levels of photosystems II cytochrome b559 α subunit, cytochrome C550, PsbY, and F-type ATP synthase (a, b) decreased. Our results indicated that electromagnetic radiation altered the photosynthesis-related protein expression levels, and aimed at the function of photosynthetic pigments, photosystems II potential activity, photosynthetic electron transport process, and photosynthetic phosphorylation process of M. aeruginosa. Based on the above evidence, that photoreaction system may be deduced as a target of electromagnetic radiation on the photosynthesis in cyanobacteria; the photoreaction system of cyanobacteria is a hypothetical "shared target effector" that responds to light and electromagnetic radiation; moreover, electromagnetic radiation does not act on the functional proteins themselves but their expression processes.

  15. Single-cell and population NF-κB dynamic responses depend on lipopolysaccharide preparation.

    Directory of Open Access Journals (Sweden)

    Miriam V Gutschow

    Full Text Available Lipopolysaccharide (LPS, found in the outer membrane of gram-negative bacteria, elicits a strong response from the transcription factor family Nuclear factor (NF-κB via Toll-like receptor (TLR 4. The cellular response to lipopolysaccharide varies depending on the source and preparation of the ligand, however. Our goal was to compare single-cell NF-κB dynamics across multiple sources and concentrations of LPS.Using live-cell fluorescence microscopy, we determined the NF-κB activation dynamics of hundreds of single cells expressing a p65-dsRed fusion protein. We used computational image analysis to measure the nuclear localization of the fusion protein in the cells over time. The concentration range spanned up to nine orders of magnitude for three E. coli LPS preparations. We find that the LPS preparations induce markedly different responses, even accounting for potency differences. We also find that the ability of soluble TNF receptor to affect NF-κB dynamics varies strikingly across the three preparations.Our work strongly suggests that the cellular response to LPS is highly sensitive to the source and preparation of the ligand. We therefore caution that conclusions drawn from experiments using one preparation may not be applicable to LPS in general.

  16. Long term effects of lipopolysaccharide on satellite glial cells in mouse dorsal root ganglia

    Energy Technology Data Exchange (ETDEWEB)

    Blum, E. [Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem 91240 (Israel); Procacci, P.; Conte, V.; Sartori, P. [Dipartimento di Scienze Biomediche per la Salute, University of Milan, via Mangiagalli 14, I-20133 Milano (Italy); Hanani, M., E-mail: hananim@cc.huji.ac.il [Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem 91240 (Israel)

    2017-01-01

    Lipopolysaccharide (LPS) has been used extensively to study neuroinflammation, but usually its effects were examined acutely (24 h<). We have shown previously that a single intraperitoneal LPS injection activated satellite glial cells (SGCs) in mouse dorsal root ganglia (DRG) and altered several functional parameters in these cells for at least one week. Here we asked whether the LPS effects would persist for 1 month. We injected mice with a single LPS dose and tested pain behavior, assessed SGCs activation in DRG using glial fibrillary acidic protein (GFAP) immunostaining, and injected a fluorescent dye intracellularly to study intercellular coupling. Electron microscopy was used to quantitate changes in gap junctions. We found that at 30 days post-LPS the threshold to mechanical stimulation was lower than in controls. GFAP expression, as well as the magnitude of dye coupling among SGCs were greater than in controls. Electron microscopy analysis supported these results, showing a greater number of gap junctions and an abnormal growth of SGC processes. These changes were significant, but less prominent than at 7 days post-LPS. We conclude that a single LPS injection exerts long-term behavioral and cellular changes. The results are consistent with the idea that SGC activation contributes to hyperalgesia. - Highlights: • A single lipopolysaccharides injection activated glia in mouse dorsal root ganglia for 30 days. • This was accompanied by increased communications by gap junctions among glia and by hyperalgesia. • Glial activation and coupling may contribute to chronic pain.

  17. Lipopolysaccharide aggravated DOI-induced Tourette syndrome: elaboration for recurrence of Tourette syndrome.

    Science.gov (United States)

    Hongyan, Long; Zhenyang, Si; Chunyan, Wang; Qingqing, Pan

    2017-12-01

    Tourette syndrome (TS) is a neurological disorder characterized by highest familial recurrence rate among neuropsychiatric diseases with complicated inheritance. Recurrence of Tourette syndrome was frequently observed in clinical. Unexpectedly, the mechanism of recurrence of Tourette syndrome was failure to elucidate. Here, we first shown that lipopolysaccharide(LPS) may played an important role in the recurrence of Tourette syndrome. The TS model in rats was induced by DOI (the selective 5-HT2A/2C agonist 1-(2, 5-dimethoxy-4-iodophenyl) -2- aminopropane). The rats were randomly divided into 4 groups:(1)Control;(2) Control + LPS; (2)TS; (3)TS + LPS. The results demonstrated that the LPS treatment significantly increased stereotypic score and autonomic activity. LPS treatment also significantly increased inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in serum and striatum. Also, highly expressed TLR4, MyD88, P-NF-κBp65, P-IκBα in TS rats were increased respectively by LPS treatment as indicted in western blot analysis and immunohistochemistry analysis. Thus, it was supposed that lipopolysaccharide(LPS) may played an important role in the recurrence of Tourette syndrome and its mechanism was related to TLR/NF-κB pathway.

  18. The role of lipopolysaccharide in infectious bone resorption of periapical lesion.

    Science.gov (United States)

    Hong, Chi-Yuan; Lin, Sze-Kwan; Kok, Sang-Heng; Cheng, Shih-Jung; Lee, Ming-Shu; Wang, Tong-Mei; Chen, Chuan-Shuo; Lin, Li-Deh; Wang, Juo-Song

    2004-03-01

    The role of lipopolysaccharide (LPS) in periapical lesion-induced bone resorption was investigated. Polymyxin B (PMB), a specific inhibitor of LPS, was evaluated to treat the apical lesion. Lipopolysaccharide isolated from two common endodontic pathogens, Fusobacterium nucleatum and Porphyromonas endodontalis, stimulated mouse macrophage (J774) to release interleukin-1alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) in a time-dependent manner. Combination of LPS further enhanced the stimulation. PMB inhibited these effects significantly. LPS also stimulated matrix metalloproteinase-1 (MMP-1) gene expression in J774, whereas anti-IL-1 alpha and anti-TNF-alpha antibodies, as well as PMB, diminished this effect. A disease model of periapical lesion was established in Wistar rat. Administration of PMB reduced the extent of lesion-associated bone resorption by 76% to approximately 80%, and simultaneously reduced the numbers of MMP-1-producing macrophages. It is suggested that LPS released from the infected root canal triggers the synthesis of IL-1 alpha and TNF-alpha from macrophages. These pro-inflammatory cytokines up-regulate the production of MMP-1 by macrophages to promote periapical bone resorption.

  19. SuhB Is a Regulator of Multiple Virulence Genes and Essential for Pathogenesis of Pseudomonas aeruginosa

    Science.gov (United States)

    Li, Kewei; Xu, Chang; Jin, Yongxin; Sun, Ziyu; Liu, Chang; Shi, Jing; Chen, Gukui; Chen, Ronghao; Jin, Shouguang; Wu, Weihui

    2013-01-01

    ABSTRACT During initial colonization and chronic infection, pathogenic bacteria encounter distinct host environments. Adjusting gene expression accordingly is essential for the pathogenesis. Pseudomonas aeruginosa has evolved complicated regulatory networks to regulate different sets of virulence factors to facilitate colonization and persistence. The type III secretion system (T3SS) and motility are associated with acute infections, while biofilm formation and the type VI secretion system (T6SS) are associated with chronic persistence. To identify novel regulatory genes required for pathogenesis, we screened a P. aeruginosa transposon (Tn) insertion library and found suhB to be an essential gene for the T3SS gene expression. The expression of suhB was upregulated in a mouse acute lung infection model, and loss of suhB resulted in avirulence. Suppression of T3SS gene expression in the suhB mutant is linked to a defective translation of the T3SS master regulator, ExsA. Further studies demonstrated that suhB mutation led to the upregulation of GacA and its downstream small RNAs, RsmY and RsmZ, triggering T6SS expression and biofilm formation while inhibiting the T3SS. Our results demonstrate that an in vivo-inducible gene, suhB, reciprocally regulates genes associated with acute and chronic infections and plays an essential role in the pathogenesis of P. aeruginosa. PMID:24169572

  20. Plant flavones enhance antimicrobial activity of respiratory epithelial cell secretions against Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Benjamin M Hariri

    Full Text Available Flavones are a class of natural plant secondary metabolites that have anti-inflammatory and anti-bacterial effects. Some flavones also activate the T2R14 bitter taste receptor, which is expressed in motile cilia of the sinonasal epithelium and activates innate immune nitric oxide (NO production. Flavones may thus be potential therapeutics for respiratory infections. Our objective was to examine the anti-microbial effects of flavones on the common sinonasal pathogens Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa, evaluating both planktonic and biofilm growth. Flavones had only very low-level antibacterial activity alone. They did not reduce biofilm formation, but did reduce production of the important P. aeruginosa inflammatory mediator and ciliotoxin pyocyanin. However, flavones exhibited synergy against P. aeruginosa in the presence of antibiotics or recombinant human lysozyme. They also enhanced the efficacy of antimicrobials secreted by cultured and primary human airway cells grown at air-liquid interface. This suggests that flavones may have anti-gram-negative potential as topical therapeutics when combined with antibiotics or in the context of innate antimicrobials secreted by the respiratory or other epithelia. This may have an additive effect when combined with T2R14-activated NO production. Additional studies are necessary to understand which flavone compounds or mixtures are the most efficacious.

  1. Interactions of methicillin resistant Staphylococcus aureus USA300 and Pseudomonas aeruginosa in polymicrobial wound infection.

    Directory of Open Access Journals (Sweden)

    Irena Pastar

    Full Text Available Understanding the pathology resulting from Staphylococcus aureus and Pseudomonas aeruginosa polymicrobial wound infections is of great importance due to their ubiquitous nature, increasing prevalence, growing resistance to antimicrobial agents, and ability to delay healing. Methicillin-resistant S. aureus USA300 is the leading cause of community-associated bacterial infections resulting in increased morbidity and mortality. We utilized a well-established porcine partial thickness wound healing model to study the synergistic effects of USA300 and P. aeruginosa on wound healing. Wound re-epithelialization was significantly delayed by mixed-species biofilms through suppression of keratinocyte growth factor 1. Pseudomonas showed an inhibitory effect on USA300 growth in vitro while both species co-existed in cutaneous wounds in vivo. Polymicrobial wound infection in the presence of P. aeruginosa resulted in induced expression of USA300 virulence factors Panton-Valentine leukocidin and α-hemolysin. These results provide evidence for the interaction of bacterial species within mixed-species biofilms in vivo and for the first time, the contribution of virulence factors to the severity of polymicrobial wound infections.

  2. A Metabolic Trade-Off Modulates Policing of Social Cheaters in Populations of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Huicong Yan

    2018-02-01

    Full Text Available Pseudomonas aeruginosa uses quorum sensing (QS to regulate the production of public goods such as the secreted protease elastase. P. aeruginosa requires the LasI–LasR QS circuit to induce elastase and enable growth on casein as the sole carbon and energy source. The LasI–LasR system also induces a second QS circuit, the RhlI–RhlR system. During growth on casein, LasR-mutant social cheaters emerge, and this can lead to a population collapse. In a minimal medium containing ammonium sulfate as a nitrogen source, populations do not collapse, and cheaters and cooperators reach a stable equilibrium; however, without ammonium sulfate, cheaters overtake the cooperators and populations collapse. We show that ammonium sulfate enhances the activity of the RhlI–RhlR system in casein medium and this leads to increased production of cyanide, which serves to control levels of cheaters. This enhancement of cyanide production occurs because of a trade-off in the metabolism of glycine: exogenous ammonium ion inhibits the transformation of glycine to 5,10-methylenetetrahydrofolate through a reduction in the expression of the glycine cleavage genes gcvP1 and gcvP2, thereby increasing the availability of glycine as a substrate for RhlR-regulated hydrogen cyanide synthesis. Thus, environmental ammonia enhances cyanide production and stabilizes QS in populations of P. aeruginosa.

  3. Complexity of resistance mechanisms to imipenem in intensive care unit strains of Pseudomonas aeruginosa.

    Science.gov (United States)

    Fournier, Damien; Richardot, Charlotte; Müller, Emeline; Robert-Nicoud, Marjorie; Llanes, Catherine; Plésiat, Patrick; Jeannot, Katy

    2013-08-01

    Pseudomonas aeruginosa can become resistant to carbapenems by both intrinsic (mutation-driven) and transferable (β-lactamase-based) mechanisms. Knowledge of the prevalence of these various mechanisms is important in intensive care units (ICUs) in order to define optimal prevention and therapeutic strategies. A total of 109 imipenem-non-susceptible (MIC >4 mg/L) strains of P. aeruginosa were collected in June 2010 from the ICUs of 26 French public hospitals. Their resistance mechanisms were characterized by phenotypic, enzymatic, western blotting and molecular methods. Single or associated imipenem resistance mechanisms were identified among the 109 strains. Seven isolates (6.4%) were found to produce a metallo-β-lactamase (one VIM-1, four VIM-2, one VIM-4 and one IMP-29). Porin OprD was lost in 94 (86.2%) strains as a result of mutations or gene disruption by various insertion sequences (ISPa1635, ISPa1328, IS911, ISPs1, IS51, IS222 and ISPa41). Thirteen other strains were shown to be regulatory mutants in which down-regulation of oprD was coupled with overexpressed efflux pumps CzcCBA (n = 1), MexXY (n = 9) and MexEF-OprN (n = 3). The lack of OprD was due to disruption of the oprD promoter by ISPsy2 in one strain and alteration of the porin signal sequence in another. Imipenem resistance in ICU P. aeruginosa strains may result from multiple mechanisms involving metallo-β-lactamase gene acquisition and genetic events (mutations and ISs) inactivating oprD, turning down its expression while increasing efflux activities or preventing insertion of porin OprD in the outer membrane. This diversity of mechanisms allows P. aeruginosa, more than any other nosocomial pathogen, to rapidly adapt to carbapenems in ICUs.

  4. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

    Science.gov (United States)

    Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

    2016-04-01

    Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

  5. Vesiculation from Pseudomonas aeruginosa under SOS.

    Science.gov (United States)

    Maredia, Reshma; Devineni, Navya; Lentz, Peter; Dallo, Shatha F; Yu, Jiehjuen; Guentzel, Neal; Chambers, James; Arulanandam, Bernard; Haskins, William E; Weitao, Tao

    2012-01-01

    Bacterial infections can be aggravated by antibiotic treatment that induces SOS response and vesiculation. This leads to a hypothesis concerning association of SOS with vesiculation. To test it, we conducted multiple analyses of outer membrane vesicles (OMVs) produced from the Pseudomonas aeruginosa wild type in which SOS is induced by ciprofloxacin and from the LexA noncleavable (lexAN) strain in which SOS is repressed. The levels of OMV proteins, lipids, and cytotoxicity increased for both the treated strains, demonstrating vesiculation stimulation by the antibiotic treatment. However, the further increase was suppressed in the lexAN strains, suggesting the SOS involvement. Obviously, the stimulated vesiculation is attributed by both SOS-related and unrelated factors. OMV subproteomic analysis was performed to examine these factors, which reflected the OMV-mediated cytotoxicity and the physiology of the vesiculating cells under treatment and SOS. Thus, SOS plays a role in the vesiculation stimulation that contributes to cytotoxicity.

  6. Transcriptome Profiling of Antimicrobial Resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Khaledi, Ariane; Schniederjans, Monika; Pohl, Sarah; Rainer, Roman; Bodenhofer, Ulrich; Xia, Boyang; Klawonn, Frank; Bruchmann, Sebastian; Preusse, Matthias; Eckweiler, Denitsa; Dötsch, Andreas; Häussler, Susanne

    2016-08-01

    Emerging resistance to antimicrobials and the lack of new antibiotic drug candidates underscore the need for optimization of current diagnostics and therapies to diminish the evolution and spread of multidrug resistance. As the antibiotic resistance status of a bacterial pathogen is defined by its genome, resistance profiling by applying next-generation sequencing (NGS) technologies may in the future accomplish pathogen identification, prompt initiation of targeted individualized treatment, and the implementation of optimized infection control measures. In this study, qualitative RNA sequencing was used to identify key genetic determinants of antibiotic resistance in 135 clinical Pseudomonas aeruginosa isolates from diverse geographic and infection site origins. By applying transcriptome-wide association studies, adaptive variations associated with resistance to the antibiotic classes fluoroquinolones, aminoglycosides, and β-lactams were identified. Besides potential novel biomarkers with a direct correlation to resistance, global patterns of phenotype-associated gene expression and sequence variations were identified by predictive machine learning approaches. Our research serves to establish genotype-based molecular diagnostic tools for the identification of the current resistance profiles of bacterial pathogens and paves the way for faster diagnostics for more efficient, targeted treatment strategies to also mitigate the future potential for resistance evolution. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  7. Modulation of lipopolysaccharide-induced chorioamnionitis in fetal sheep by maternal betamethasone.

    Science.gov (United States)

    Wolfe, Katherine B; Snyder, Candice C; Gisslen, Tate; Kemp, Matthew W; Newnham, John P; Kramer, Boris W; Jobe, Alan H; Kallapur, Suhas

    2013-12-01

    We tested the hypothesis that the order of exposure to maternal betamethasone and intra-amniotic (IA) lipopolysaccharide (LPS) will differentially modulate inflammation in the chorioamnion. Time-mated Merino ewes with singleton fetuses received saline alone, IA LPS alone, maternal betamethasone before LPS, or betamethasone after LPS. We assessed inflammatory markers in the chorioamnion and the amniotic fluid. Inflammatory cell infiltration, expression of myeloperoxidase, serum amyloid A3 (acute phase reactant) in the chorioamnion, and levels of interleukin (IL)-8 in the amniotic fluid increased 7 days after LPS exposure. Betamethasone prior to LPS decreased infiltration of the inflammatory cells, CD3+ T cells, and decreased the levels of IL-1β and IL-8 in the amniotic fluid. Betamethasone 7 days prior to LPS exposure suppressed LPS-induced inflammation. The markers of inflammation largely had returned to the baseline 14 days after LPS exposure.

  8. Lipopolysaccharide-binding protein: localization in secretory granules of Paneth cells in the mouse small intestine

    DEFF Research Database (Denmark)

    Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte

    2009-01-01

    Lipopolysaccharide (LPS)-binding protein (LBP) is an acute-phase protein involved in the host's response to endotoxin and mainly synthesized and secreted to the blood by the liver. But in addition, LBP is also made by extrahepatic cells, including the enterocyte-like cell line Caco-2. To study...... in closer detail the synthesis and storage of LBP in the intestinal mucosal epithelium, we performed an immunolocalization of LBP in mouse small intestine. By immunofluorescence microscopy, an antibody recognizing the 58-60 kDa protein of LBP distinctly labeled a small population of cells located deep...... into the crypts. This cell population was also positive for lysozyme and alpha-defensin 4, identifying Paneth cells as the main intestinal LBP-producing cells. By immunogold electron microscopy, intense labeling was observed in the secretory granules of these cells. We conclude that Paneth cells express LBP...

  9. Lipopolysaccharide impairs hepatocyte ureagenesis from ammonia: involvement of mitochondrial aquaporin-8.

    Science.gov (United States)

    Soria, Leandro R; Marrone, Julieta; Molinas, Sara M; Lehmann, Guillermo L; Calamita, Giuseppe; Marinelli, Raúl A

    2014-05-02

    We recently reported that hepatocyte mitochondrial aquaporin-8 (mtAQP8) channels facilitate the uptake of ammonia and its metabolism into urea. Here we studied the effect of bacterial lipopolysaccharides (LPS) on ammonia-derived ureagenesis. In LPS-treated rats, hepatic mtAQP8 protein expression and diffusional ammonia permeability (measured utilizing ammonia analogues) of liver inner mitochondrial membranes were downregulated. NMR studies using 15N-labeled ammonia indicated that basal and glucagon-induced ureagenesis from ammonia were significantly reduced in hepatocytes from LPS-treated rats. Our data suggest that hepatocyte mtAQP8-mediated ammonia removal via ureagenesis is impaired by LPS, a mechanism potentially relevant to the molecular pathogenesis of defective hepatic ammonia detoxification in sepsis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  10. 33 original article infections a pseudomonas aeruginosa dans un

    African Journals Online (AJOL)

    boaz

    COPYRIGHT 2014. AFR. J. CLN. EXPER. .... Effective management of P. aeruginosa infections requires good ... a guide for doctors managing patients with. Pseudomonas .... Principles and practice of infectious diseases.5th edition. Edited by ...

  11. Resistance patterns of Pseudomonas aeruginosa isolated from HIV ...

    African Journals Online (AJOL)

    negative bacilli in patients with impaired host defences emphasizes the need for information on the antibiotic susceptibility of the organisms that infects such patients. Pseudomonas aeruginosa are becoming increasingly resistant to ...

  12. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    The susceptibility of Caenorhabditis elegans to different virulent phenotypes of Pseudomonas aeruginosa makes the worms an excellent model for studying host-pathogen interactions. Including the recently described liquid killing, five different killing assays are now available offering superb

  13. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, H.K.; Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. OBJECTIVES......: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search May 2008) and PubMed using the terms vaccin* AND cystic...... fibrosis (last search May 2008). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis. DATA COLLECTION AND ANALYSIS: The authors independently selected trials...

  14. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2015-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....... This is an update of a previously published review. OBJECTIVES: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30...... March 2015). We previously searched PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic...

  15. [Risk factors for Pseudomonas aeruginosa infections, resistant to carbapenem].

    Science.gov (United States)

    Ghibu, Laura; Miftode, Egidia; Teodor, Andra; Bejan, Codrina; Dorobăţ, Carmen Mihaela

    2010-01-01

    Since their introduction in clinical practice,carbapenems have been among the most powerful antibiotics for treating serious infections cased by Gram-negative nosocomial pathogens, including Pseudomonas aeruginosa. The emergence of betalactamases with carbapenem-hydrolyzing activity is of major clinical concern. Pseudomonas aeruginosa is a leading cause of nosocomial infection. Risk factors for colonization with carbapenems-resistant Pseudomonas in hospital are: history of P. aeruginosa infection or colonization within the previous year, (length of hospital stay, being bedridden or in the ICU, mechanical ventilation, malignant disease, and history of chronic obstructive pulmonary disease have all been identified as independent risk factors for MDR P. aeruginosa infection. Long-term-care facilities are also reservoirs of resistant bacteria. Risk factors for colonization of LTCF residents with resistant bacteria included age > 86 years, antibiotic treatment in the previous 3 months, indwelling devices, chronic obstructive pulmonary disease, physical disability, and the particular LTCF unit.

  16. Pseudomonas aeruginosa diversity in distinct paediatric patient groups

    DEFF Research Database (Denmark)

    Tramper-Stranders, G.A.; Ent, C.K. van der; Wolfs, T.F.

    2008-01-01

    the other groups. A group of clonal isolates was observed among patients from the CF-chronic and CF-1 groups. These or different clonal isolates were not encountered among the three other patient groups. No characteristic resistance pattern could be identified among isolates from the distinct patient groups......Pseudomonas aeruginosa is a pathogen that often infects patients who are either immunocompromised or have local defects in host defences. It is known that cystic fibrosis (CF) patients are sometimes infected with certain clonal isolates. It is not clear whether these clonal isolates also infect non......-CF patients and whether clonality of isolates occurs in other patient groups. The aim of this study was to investigate P. aeruginosa diversity and the occurrence of clones within five distinct paediatric patient groups susceptible to P. aeruginosa infection. P. aeruginosa isolates were cultured from 157...

  17. The resistome of Pseudomonas aeruginosa in relationship to phenotypic susceptibility.

    Science.gov (United States)

    Kos, Veronica N; Déraspe, Maxime; McLaughlin, Robert E; Whiteaker, James D; Roy, Paul H; Alm, Richard A; Corbeil, Jacques; Gardner, Humphrey

    2015-01-01

    Many clinical isolates of Pseudomonas aeruginosa cause infections that are difficult to eradicate due to their resistance to a wide variety of antibiotics. Key genetic determinants of resistance were identified through genome sequences of 390 clinical isolates of P. aeruginosa, obtained from diverse geographic locations collected between 2003 and 2012 and were related to microbiological susceptibility data for meropenem, levofloxacin, and amikacin. β-Lactamases and integron cassette arrangements were enriched in the established multidrug-resistant lineages of sequence types ST111 (predominantly O12) and ST235 (O11). This study demonstrates the utility of next-generation sequencing (NGS) in defining relevant resistance elements and highlights the diversity of resistance determinants within P. aeruginosa. This information is valuable in furthering the design of diagnostics and therapeutics for the treatment of P. aeruginosa infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. The Enzymes of the Ammonia Assimilation in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Janssen, Dick B.; Camp, Huub J.M. op den; Leenen, Pieter J.M.; Drift, Chris van der

    1980-01-01

    Glutamine synthetase from Pseudomonas aeruginosa is regulated by repression/derepression of enzyme synthesis and by adenylylation/deadenylylation control. High levels of deadenylylated biosynthetically active glutamine synthetase were observed in cultures growing with limiting amounts of nitrogen

  19. Acquisition and Role of Molybdate in Pseudomonas aeruginosa

    Science.gov (United States)

    Pederick, Victoria G.; Eijkelkamp, Bart A.; Ween, Miranda P.; Begg, Stephanie L.; Paton, James C.

    2014-01-01

    In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO42−). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition. PMID:25172858

  20. Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice

    OpenAIRE

    Szentirmai, Éva; Krueger, James M.

    2013-01-01

    Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, ...

  1. CHARACTERIZATION OF AN INTRAVENOUS LIPOPOLYSACCHARIDE INFLAMMATION MODEL IN BROILER CHICKENS

    OpenAIRE

    De Boever , Sandra; Croubels , Siska; Meyer , Evelyne; Sys , Stanislas; Beyaert , Rudi; Ducatelle , Richard; De Backer , Patrick

    2009-01-01

    Abstract Intravenous administration of lipopolysaccharide (LPS) from Escherichia coli O127:B8 at a dose of 1,500,000 units/kg BW evoked a hypothermic response followed by a fever phase in five week old broiler chickens. The hypothermic phase coincided with a severe decrease in blood pressure. We assume that this decrease in blood pressure is, at least partly, responsible for the hypothermic phase of the body temperature curve. LPS administration also caused a decrease in circulatin...

  2. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang

    2016-01-01

    Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino...... acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm...

  3. Copper sulfate pentahydrate reduced epithelial cytotoxicity induced by lipopolysaccharide from enterogenic bacteria.

    Science.gov (United States)

    Feyzi, Adel; Delkhosh, Aref; Nasrabadi, Hamid Tayefi; Cheraghi, Omid; Khakpour, Mansour; Barekati-Mowahed, Mazyar; Soltani, Sina; Mohammadi, Seyede Momeneh; Kazemi, Masoumeh; Hassanpour, Mehdi; Rezabakhsh, Aysa; Maleki-Dizaji, Nasrin; Rahbarghazi, Reza; Namdarian, Reza

    2017-05-01

    The over usage of multiple antibiotics contributes to the emergence of a whole range of antibiotic-resistant strains of bacteria causing enterogenic infections in poultry science. Therefore, finding an appropriate alternative natural substance carrying an antibacterial capacity would be immensely beneficial. It has been previously discovered that the different types of cupric salts, especially copper sulfate pentahydrate (CuSO 4 ·5H 2 O), to carry a potent bactericidal capacity. We investigated the neutralizing effect of CuSO 4 ·5H 2 O (6.25μg/ml) on the reactive oxygen species generation, and expression of MyD88, an essential adaptor protein of Toll-like receptor, and NF-κB in three intestinal epithelial cell lines exposed to 50ng/ml lipopolysaccharide. In order to find the optimal cupric sulfate concentration without enteritis-inducing toxicity, broiler chickens were initially fed with water containing 0.4, 0.5, and 1mg/l during a period of 4days. After determination of appropriate dosage, two broiler chickens and turkey flocks with enteritis were fed with cupric compound for 4days. We found that cupric sulfate can lessen the cytotoxic effect of lipopolysaccharide by reducing the reactive oxygen species content (psulfate. The copper sulfate in doses lower than 0.4mg/ml expressed no cytotoxic effect on the liver, kidney, and the intestinal tract while a concentration of 0.5 and 1mg/ml contributed to a moderate to severe tissue injuries. Pearson Chi-Square analysis revealed the copper cation significantly diminished the rate of mortality during 4-day feeding of broiler chicken and turkey with enteritis (p=0.000). Thus, the results briefed above all confirm the potent anti-bactericidal feature of cupric sulfate during the course of enteritis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Heme oxygenase-1 induction alters chemokine regulation and ameliorates human immunodeficiency virus-type-1 infection in lipopolysaccharide-stimulated macrophages

    International Nuclear Information System (INIS)

    Zhou, Zhao-Hua; Kumari, Namita; Nekhai, Sergei; Clouse, Kathleen A.; Wahl, Larry M.; Yamada, Kenneth M.; Dhawan, Subhash

    2013-01-01

    Highlights: •Lipopolysaccharide stimulation of heme oxygenase-1 (HO-1) ameliorated HIV-1 infection of primary human macrophages. •The partial protection by HO-1 against HIV infection was associated with induction of chemokines such as MIP1α and MIP1β. •This mechanism explains lipopolysaccharide-stimulated HO-1-mediated inhibition of HIV-1 infection of macrophages. -- Abstract: We have elucidated a putative mechanism for the host resistance against HIV-1 infection of primary human monocyte-derived macrophages (MDM) stimulated with lipopolysaccharide (LPS). We show that LPS-activated MDM both inhibited HIV-1 entry into the cells and were refractory to post-entry productive viral replication. LPS-treated cells were virtually negative for mature virions as revealed by transmission electron microscopy. LPS activation of MDM markedly enhanced the expression of heme oxygenase-1 (HO-1), a potent inducible cytoprotective enzyme. Increased HO-1 expression was accompanied by elevated production of macrophage inflammatory chemokines (MIP1α and MIP1β) by LPS-activated MDM, significantly decreased surface chemokine receptor-5 (CCR-5) expression, and substantially reduced virus replication. Treatment of cells with HO-1 inhibitor SnPP IX (tin protoporphyrin IX) attenuated the LPS-mediated responses, HIV-1 replication and secretion of MIP1α, MIP1β, and LD78β chemokines with little change in surface CCR-5 expression. These results identify a novel role for HO-1 in the modulation of host immune response against HIV infection of MDM

  5. Pseudomonas aeruginosa inhibits the growth of Cryptococcus species.

    Science.gov (United States)

    Rella, Antonella; Yang, Mo Wei; Gruber, Jordon; Montagna, Maria Teresa; Luberto, Chiara; Zhang, Yong-Mei; Del Poeta, Maurizio

    2012-06-01

    Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.

  6. [Susceptibility and resistence of Pseudomonas aeruginosa to antimicrobial agents].

    Science.gov (United States)

    Gamero Delgado, M C; García-Mayorgas, A D; Rodríguez, F; Ibarra, A; Casal, M

    2007-06-01

    Pseudomonas aeruginosa is an opportunistic microorganism that is frequently the cause of nosocomial infections. Multiple mechanisms are involved in its natural and acquired resistance to many of the antimicrobial agents commonly used in clinical practice. The objective of this study was to assess the susceptibility and resistance patterns of P. aeruginosa strains isolated in Hospital Reina Sofia between 2000 and 2005, as well as to analyze the differences between intrahospital and extrahospital isolates in 2005 and to compare the results with those obtained in other studies. A total of 3,019 strains of P. aeruginosa from different hospitals and nonhospital settings were evaluated, taking into consideration their degree of sensitivity to different antibiotics. The MICs were determined by means of the Wider I automated system (Soria Melguizo), taking into consideration the criteria of susceptibility and resistance recommended by MENSURA. Results of the analysis showed that P. aeruginosa maintained similar levels of antimicrobial susceptibility during the period 2000-2005, with increased susceptibility to amikacin, gentamicin and tobramycin. There were also important differences in the degree of susceptibility between intrahospital and extrahospital strains, except for imipenem and fosfomycin. The intrahospital difference in susceptibility was also evaluated, emphasizing the importance of periodically studying susceptibility and resistance patterns of P. aeruginosa in each setting in order to evaluate different therapeutic guidelines, as it is not always advisable to extrapolate data from different regions. These differences can be explained by the different use of antibiotics in each center and the geographic variations of the resistance mechanisms of P. aeruginosa.

  7. Post-secretional activation of Protease IV by quorum sensing in Pseudomonas aeruginosa.

    Science.gov (United States)

    Oh, Jungmin; Li, Xi-Hui; Kim, Soo-Kyong; Lee, Joon-Hee

    2017-06-30

    Protease IV (PIV), a key virulence factor of Pseudomonas aeruginosa is a secreted lysyl-endopeptidase whose expression is induced by quorum sensing (QS). We found that PIV expressed in QS mutant has severe reduction of activity in culture supernatant (CS), even though it is overexpressed to high level. PIV purified from the QS mutant (M-PIV) had much lower activity than the PIV purified from wild type (P-PIV). We found that the propeptide cleaved from prepro-PIV was co-purified with M-PIV, but never with P-PIV. Since the activity of M-PIV was restored by adding the CS of QS-positive and PIV-deficient strain, we hypothesized that the propeptide binds to and inhibits PIV, and is degraded to activate PIV by a QS-dependent factor. In fact, the CS of the QS-positive and PIV-deficient strain was able to degrade the propeptide. Since the responsible factor should be a QS-dependently expressed extracellular protease, we tested QS-dependent proteases of P. aeruginosa and found that LasB (elastase) can degrade the propeptide and activate M-PIV. We purified the propeptide of PIV and confirmed that the propeptide can bind to and inhibit PIV. We suggest that PIV is post-secretionally activated through the extracellular degradation of the propeptide by LasB, a QS-dependent protease.

  8. Modification of Salmonella Lipopolysaccharides Prevents the Outer Membrane Penetration of Novobiocin

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, Thatyane M.; Martynowycz, Michael W.; Andreev, Konstantin; Kuzmenko, Ivan; Nikaido, Hiroshi; Gidalevitz, David

    2015-12-01

    Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate lipopolysaccharides from isogenic mutants of Salmonella sp., one lacking the modification, the other fully modified. These lipopolysaccharides were reconstituted asmonolayers at the air-water interface, and their properties, aswell as their interaction with a large lipophilic drug, novobiocin, was studied. X-ray reflectivity showed that the drug penetrated the monolayer of the unmodified lipopolysaccharides reaching the hydrophobic region,butwas prevented fromthis penetration intothemodified lipopolysaccharides.Results correlatewith behavior of bacterial cells, which become resistant to antibiotics after PhoPQ-regulated modifications. Grazing incidence x-ray diffraction showed that novobiocin produced a striking increase in crystalline coherence length, and the size of the near-crystalline domains.

  9. Pseudomonas aeruginosa outer membrane vesicles triggered by human mucosal fluid and lysozyme can prime host tissue surfaces for bacterial adhesion

    Directory of Open Access Journals (Sweden)

    Matteo Maria Emiliano Metruccio

    2016-06-01

    Full Text Available Pseudomonas aeruginosa is a leading cause of human morbidity and mortality that often targets epithelial surfaces. Host immunocompromise, or the presence of indwelling medical devices, including contact lenses, can predispose to infection. While medical devices are known to accumulate bacterial biofilms, it is not well understood why resistant epithelial surfaces become susceptible to P. aeruginosa. Many bacteria, including P. aeruginosa, release Outer Membrane Vesicles (OMVs in response to stress that can fuse with host cells to alter their function. Here, we tested the hypothesis that mucosal fluid can trigger OMV release to compromise an epithelial barrier. This was tested using tear fluid and corneal epithelial cells in vitro and in vivo. After 1 h both human tear fluid, and the tear component lysozyme, greatly enhanced OMV release from P. aeruginosa strain PAO1 compared to PBS controls (~100 fold. TEM and SDS-PAGE showed tear fluid and lysozyme-induced OMVs were similar in size and protein composition, but differed from biofilm-harvested OMVs, the latter smaller with fewer proteins. Lysozyme-induced OMVs were cytotoxic to human corneal epithelial cells in vitro and murine corneal epithelium in vivo. OMV exposure in vivo enhanced Ly6G/C expression at the corneal surface, suggesting myeloid cell recruitment, and primed the cornea for bacterial adhesion (~4-fold, P < 0.01. Sonication disrupted OMVs retained cytotoxic activity, but did not promote adhesion, suggesting the latter required OMV-mediated events beyond cell killing. These data suggest that mucosal fluid induced P. aeruginosa OMVs could contribute to loss of epithelial barrier function during medical device-related infections.

  10. ST2 is essential for Th2 responsiveness and resistance to pseudomonas aeruginosa keratitis.

    Science.gov (United States)

    Huang, Xi; Du, Wenjin; Barrett, Ronald P; Hazlett, Linda D

    2007-10-01

    To elucidate the role of ST2, a member of the TLR/IL-1R (TIR) superfamily, in protecting against Pseudomonas aeruginosa keratitis in BALB/c mice. ST2 mRNA and protein expression levels were tested by real-time PCR and Western-blot in C57BL/6 (B6; susceptible) versus BALB/c (resistant) mice before and after P. aeruginosa (strain 19660; American Type Culture Collection, Philadelphia, PA) challenge. Infected BALB/c mice also were tested after subconjunctival injection with recombinant murine (rm)ST2 or PBS. Disease was monitored by clinical score, slit lamp, bacterial plate count, a myeloperoxidase (MPO) assay to measure polymorphonuclear neutrophil (PMN) infiltrate, real-time RT-PCR, and ELISA. ST2 mRNA and protein were constitutively expressed in the uninfected normal corneas of both mouse groups. ST2 levels in the cornea of BALB/c compared with B6 mice were elevated significantly at 1 to 3 days post infection (PI), peaked at 3 and decreased at 5 days PI. BALB/c mice treated with rmST2 showed increased corneal opacity and perforation (at 5 days PI) when compared with PBS controls. rmST2- versus PBS-injected mice exhibited increased bacterial load, PMN infiltrate, and higher corneal mRNA levels for IL-1beta, MIP-2, IL-6, IL-1R1, and Th1-type cytokine such as IFN-gamma. Protein levels for IL-1beta, MIP-2, and IL-6 also were significantly upregulated, whereas the Th2 cytokines IL-4 (mRNA), IL-5 (mRNA), and IL-10 (mRNA and protein) were significantly reduced. ST2 is critical in resistance to P. aeruginosa keratitis, functioning to reduce corneal infection (bacterial load) and inflammation by negatively regulating proinflammatory cytokines and inhibiting type-1 immunity, but upregulating type-2 cytokine production, particularly IL-10.

  11. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

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    Peter J Hart

    Full Text Available Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

  12. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

    Science.gov (United States)

    Hart, Peter J; O'Shaughnessy, Colette M; Siggins, Matthew K; Bobat, Saeeda; Kingsley, Robert A; Goulding, David A; Crump, John A; Reyburn, Hugh; Micoli, Francesca; Dougan, Gordon; Cunningham, Adam F; MacLennan, Calman A

    2016-01-01

    Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

  13. Bioadsorption characteristics of Pseudomonas aeruginosa PAOI

    Directory of Open Access Journals (Sweden)

    Kőnig-Péter Anikó

    2014-01-01

    Full Text Available Biosorption of Cd(II and Pb(II ions from aqueous solution using lyophilized Pseudomonas aeruginosa (PAOI cells were observed under various experimental conditions. The effect of pH, initial metal concentration, equilibration time and temperature on bioadsorption was investigated. The optimum pH value for Pb(II adsorption was found to be 5.0, and for Cd(II 5.0 − 6.0. The Pb(II and Cd(II bioadsorption equilibrium were analyzed by using Freundlich and Langmuir model using nonlinear least-squares estimation. The experimental maximum uptake capacity of Pb(II and Cd(II was estimated to be 164 mg g-1 and 113 mg g-1, respectively. For biosorption kinetic study the pseudo second-order kinetic model was applied at various temperatures. The temperature had no significant effect on Pb(II bioadsorption. In case of Cd(II bioadsorption the adsorbed amount decreased with increasing temperature.

  14. Adherence of Pseudomonas aeruginosa to contact lenses

    International Nuclear Information System (INIS)

    Miller, M.J.

    1988-01-01

    The purpose of this research was to examined the interactions of P. aeruginosa with hydrogel contact lenses and other substrata, and characterize adherence to lenses under various physiological and physicochemical conditions. Isolates adhered to polystyrene, glass, and hydrogel lenses. With certain lens types, radiolabeled cells showed decreased adherence with increasing water content of the lenses, however, this correlation with not found for all lenses. Adherence to rigid gas permeable lenses was markedly greater than adherence to hydrogels. Best adherence occurred near pH 7 and at a sodium chloride concentration of 50 mM. Passive adhesion of heat-killed cells to hydrogels was lower than the adherence obtained of viable cells. Adherence to hydrogels was enhanced by mucin, lactoferrin, lysozyme, IgA, bovine serum albumin, and a mixture of these macromolecules. Adherence to coated and uncoated lenses was greater with a daily-wear hydrogel when compared with an extended-wear hydrogel of similar polymer composition. Greater adherence was attributed to a higher concentration of adsorbed macromolecules on the 45% water-content lens in comparison to the 55% water-content lens

  15. Spaceflight promotes biofilm formation by Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Wooseong Kim

    Full Text Available Understanding the effects of spaceflight on microbial communities is crucial for the success of long-term, manned space missions. Surface-associated bacterial communities, known as biofilms, were abundant on the Mir space station and continue to be a challenge on the International Space Station. The health and safety hazards linked to the development of biofilms are of particular concern due to the suppression of immune function observed during spaceflight. While planktonic cultures of microbes have indicated that spaceflight can lead to increases in growth and virulence, the effects of spaceflight on biofilm development and physiology remain unclear. To address this issue, Pseudomonas aeruginosa was cultured during two Space Shuttle Atlantis missions: STS-132 and STS-135, and the biofilms formed during spaceflight were characterized. Spaceflight was observed to increase the number of viable cells, biofilm biomass, and thickness relative to normal gravity controls. Moreover, the biofilms formed during spaceflight exhibited a column-and-canopy structure that has not been observed on Earth. The increase in the amount of biofilms and the formation of the novel architecture during spaceflight were observed to be independent of carbon source and phosphate concentrations in the media. However, flagella-driven motility was shown to be essential for the formation of this biofilm architecture during spaceflight. These findings represent the first evidence that spaceflight affects community-level behaviors of bacteria and highlight the importance of understanding how both harmful and beneficial human-microbe interactions may be altered during spaceflight.

  16. An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections.

    Science.gov (United States)

    Koeva, Martina; Gutu, Alina D; Hebert, Wesley; Wager, Jeffrey D; Yonker, Lael M; O'Toole, George A; Ausubel, Frederick M; Moskowitz, Samuel M; Joseph-McCarthy, Diane

    2017-12-01

    Bacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary-phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters. Copyright © 2017 American Society for Microbiology.

  17. Magnesium limitation is an environmental trigger of the Pseudomonas aeruginosa biofilm lifestyle.

    Directory of Open Access Journals (Sweden)

    Heidi Mulcahy

    Full Text Available Biofilm formation is a conserved strategy for long-term bacterial survival in nature and during infections. Biofilms are multicellular aggregates of cells enmeshed in an extracellular matrix. The RetS, GacS and LadS sensors control the switch from a planktonic to a biofilm mode of growth in Pseudomonas aeruginosa. Here we detail our approach to identify environmental triggers of biofilm formation by investigating environmental conditions that repress expression of the biofilm repressor RetS. Mg(2+ limitation repressed the expression of retS leading to increased aggregation, exopolysaccharide (EPS production and biofilm formation. Repression of retS expression under Mg(2+ limitation corresponded with induced expression of the GacA-controlled small regulatory RNAs rsmZ and rsmY and the EPS biosynthesis operons pel and psl. We recently demonstrated that extracellular DNA sequesters Mg(2+ cations and activates the cation-sensing PhoPQ two-component system, which leads to increased antimicrobial peptide resistance in biofilms. Here we show that exogenous DNA and EDTA, through their ability to chelate Mg(2+, promoted biofilm formation. The repression of retS in low Mg(2+ was directly controlled by PhoPQ. PhoP also directly controlled expression of rsmZ but not rsmY suggesting that PhoPQ controls the equilibrium of the small regulatory RNAs and thus fine-tunes the expression of genes in the RetS pathway. In summary, Mg(2+ limitation is a biologically relevant environmental condition and the first bonafide environmental signal identified that results in transcriptional repression of retS and promotes P. aeruginosa biofilm formation.

  18. Synthesis, characterization and immunological properties of LPS-based conjugate vaccine composed of O-polysaccharide from pseudomonas aeruginosa IATS 10 bound to recombinant exoprotein A

    International Nuclear Information System (INIS)

    Abu-baker, N. F.; Masoud, H. A.; Jaber, B. M.

    2008-01-01

    Pseudomonas aeruginosa is an improtant opportunistic pathogen that can cause infection in immunocompromised patient. Lipopolysaccharide (LPS), the major surface antigen of P. aeruginosa, is immunogenic and elieits protective antibodies in animals. The O-polysaccharids (O-PS) from international Antigenic typing Scheme (IATS) 10, the antigenic determinant of LPS, was coupled to recombinant exoprotein A (rPA) through adipic acid dihydrazide (ADH) mediated by carbodiimide condensation reaction. Mice were immunized with the conjugate emulsifield with monophosphoryl lipid A-trehalose dicorynomycolate (MPL-T) and freund's adjuvants. The conjiugate emulsified with MPL-T adjuvant elicited the highest level of IgG and IgM followed by freuns's adjuvant. IgG titers using both MPL-T and freund's adjuvants were recorded to be higher than IgM titers after the second post of the immunization. Immunization of mice with the prepared conjugates emulsified with MPL-T and freund's adjvaided provide high level of protection (100%) against ten times the LD50 of homologous strain of P. aeruginsoa. the elicited high IgG level and the in vivo protection test results provided good evidences for the possible protection of the conjugate aginst subsequent infection with the pathogen. These findings will enable us to use it as protective vaccine candidate (authors).

  19. Multiple mechanisms involved in diabetes protection by lipopolysaccharide in non-obese diabetic mice

    International Nuclear Information System (INIS)

    Wang, Jun; Cao, Hui; Wang, Hongjie; Yin, Guoxiao; Du, Jiao; Xia, Fei; Lu, Jingli; Xiang, Ming

    2015-01-01

    Toll-like receptor 4 (TLR4) activation has been proposed to be important for islet cell inflammation and eventually β cell loss in the course of type 1 diabetes (T1D) development. However, according to the “hygiene hypothesis”, bacterial endotoxin lipopolysaccharide (LPS), an agonist on TLR4, inhibits T1D progression. Here we investigated possible mechanisms for the protective effect of LPS on T1D development in non-obese diabetic (NOD) mice. We found that LPS administration to NOD mice during the prediabetic state neither prevented nor reversed insulitis, but delayed the onset and decreased the incidence of diabetes, and that a multiple-injection protocol is more effective than a single LPS intervention. Further, LPS administration suppressed spleen T lymphocyte proliferation, increased the generation of CD4 + CD25 + Foxp3 + regulatory T cells (Tregs), reduced the synthesis of strong Th1 proinflammatory cytokines, and downregulated TLR4 and its downstream MyD88-dependent signaling pathway. Most importantly, multiple injections of LPS induced a potential tolerogenic dendritic cell (DC) subset with low TLR4 expression without influencing the DC phenotype. Explanting DCs from repeated LPS-treated NOD mice into NOD/SCID diabetic mice conferred sustained protective effects against the progression of diabetes in the recipients. Overall, these results suggest that multiple mechanisms are involved in the protective effects of LPS against the development of diabetes in NOD diabetic mice. These include Treg induction, down-regulation of TLR4 and its downstream MyD88-dependent signaling pathway, and the emergence of a potential tolerogenic DC subset. - Highlights: • Administration of lipopolysaccharide (LPS) prevented type 1 diabetes in NOD mice. • Downregulating TLR4 level and MyD88-dependent pathway contributed to protection of LPS. • LPS administration also hampered DC maturation and promoted Treg differentiation

  20. Multiple mechanisms involved in diabetes protection by lipopolysaccharide in non-obese diabetic mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Department of Pharmacology, College of Medicine, Wuhan University of Science and Technology, Wuhan (China); Cao, Hui [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Wang, Hongjie [Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, FL (United States); Yin, Guoxiao; Du, Jiao; Xia, Fei; Lu, Jingli [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Xiang, Ming, E-mail: xiangming@mails.tjmu.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)

    2015-06-15

    Toll-like receptor 4 (TLR4) activation has been proposed to be important for islet cell inflammation and eventually β cell loss in the course of type 1 diabetes (T1D) development. However, according to the “hygiene hypothesis”, bacterial endotoxin lipopolysaccharide (LPS), an agonist on TLR4, inhibits T1D progression. Here we investigated possible mechanisms for the protective effect of LPS on T1D development in non-obese diabetic (NOD) mice. We found that LPS administration to NOD mice during the prediabetic state neither prevented nor reversed insulitis, but delayed the onset and decreased the incidence of diabetes, and that a multiple-injection protocol is more effective than a single LPS intervention. Further, LPS administration suppressed spleen T lymphocyte proliferation, increased the generation of CD4{sup +}CD25{sup +}Foxp3{sup +} regulatory T cells (Tregs), reduced the synthesis of strong Th1 proinflammatory cytokines, and downregulated TLR4 and its downstream MyD88-dependent signaling pathway. Most importantly, multiple injections of LPS induced a potential tolerogenic dendritic cell (DC) subset with low TLR4 expression without influencing the DC phenotype. Explanting DCs from repeated LPS-treated NOD mice into NOD/SCID diabetic mice conferred sustained protective effects against the progression of diabetes in the recipients. Overall, these results suggest that multiple mechanisms are involved in the protective effects of LPS against the development of diabetes in NOD diabetic mice. These include Treg induction, down-regulation of TLR4 and its downstream MyD88-dependent signaling pathway, and the emergence of a potential tolerogenic DC subset. - Highlights: • Administration of lipopolysaccharide (LPS) prevented type 1 diabetes in NOD mice. • Downregulating TLR4 level and MyD88-dependent pathway contributed to protection of LPS. • LPS administration also hampered DC maturation and promoted Treg differentiation.

  1. Insertional inactivation of oprD in carbapenem-resistant Pseudomonas aeruginosa strains isolated from burn patients in Tehran, Iran.

    Science.gov (United States)

    Shariati, A; Azimi, T; Ardebili, A; Chirani, A S; Bahramian, A; Pormohammad, A; Sadredinamin, M; Erfanimanesh, S; Bostanghadiri, N; Shams, S; Hashemi, A

    2018-01-01

    In this study, we report the insertion sequence IS Ppu 21 in the opr D porin gene of carbapenem-resistant Pseudomonas aeruginosa isolates from burn patients in Tehran, Iran. Antibiotic susceptibility tests for P. aeruginosa isolates were determined. Production of metallo-β-lactamases (MBLs) and carbapenemase was evaluated and the β-lactamase-encoding and aminoglycoside-modifying enzyme genes were investigated by PCR and sequencing methods. The mRNA transcription level of oprD and mex efflux pump genes were evaluated by real-time PCR. The outer membrane protein profile was determined by SDS-PAGE. The genetic relationship between the P. aeruginosa isolates was assessed by random amplified polymorphic DNA PCR. In all, 10.52% (10/95) of clinical isolates of P. aeruginosa harboured the IS Ppu 21 insertion element in the opr D gene. The extended-spectrum β-lactamase-encoding gene in IS Ppu 21-carrying isolates was bla TEM . PCR assays targeting MBL and carbapenemase-encoding genes were also negative in all ten isolates. The rmt A, aad A, aad B and arm A genes were positive in all IS Ppu 21 harbouring isolates. The relative expression levels of the mex X, mex B, mex T and mex D genes in ten isolates ranged from 0.1- to 1.4-fold, 1.1- to 3.68-fold, 0.3- to 8.22-fold and 1.7- to 35.17-fold, respectively. The relative expression levels of the oprD in ten isolates ranged from 0.57- to 35.01-fold, which was much higher than those in the control strain P. aeruginosa PAO1. Evaluation of the outer membrane protein by SDS-PAGE suggested that opr D was produced at very low levels by all isolates. Using random amplified polymorphic DNA PCR genotyping, eight of the ten isolates containing IS Ppu 21 were shown to be clonally related. The present study describes a novel molecular mechanism, IS Ppu 21 insertion of the opr D gene, associated with carbapenem resistance in clinical P. aeruginosa isolates.

  2. Structural and antimicrobial properties of human pre-elafin/trappin-2 and derived peptides against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Gagné Stéphane M

    2010-10-01

    Full Text Available Abstract Background Pre-elafin/trappin-2 is a human innate defense molecule initially described as a potent inhibitor of neutrophil elastase. The full-length protein as well as the N-terminal "cementoin" and C-terminal "elafin" domains were also shown to possess broad antimicrobial activity, namely against the opportunistic pathogen P. aeruginosa. The mode of action of these peptides has, however, yet to be fully elucidated. Both domains of pre-elafin/trappin-2 are polycationic, but only the structure of the elafin domain is currently known. The aim of the present study was to determine the secondary structures of the cementoin domain and to characterize the antibacterial properties of these peptides against P. aeruginosa. Results We show here that the cementoin domain adopts an α-helical conformation both by circular dichroism and nuclear magnetic resonance analyses in the presence of membrane mimetics, a characteristic shared with a large number of linear polycationic antimicrobial peptides. However, pre-elafin/trappin-2 and its domains display only weak lytic properties, as assessed by scanning electron micrography, outer and inner membrane depolarization studies with P. aeruginosa and leakage of liposome-entrapped calcein. Confocal microscopy of fluorescein-labeled pre-elafin/trappin-2 suggests that this protein possesses the ability to translocate across membranes. This correlates with the finding that pre-elafin/trappin-2 and elafin bind to DNA in vitro and attenuate the expression of some P. aeruginosa virulence factors, namely the biofilm formation and the secretion of pyoverdine. Conclusions The N-terminal cementoin domain adopts α-helical secondary structures in a membrane mimetic environment, which is common in antimicrobial peptides. However, unlike numerous linear polycationic antimicrobial peptides, membrane disruption does not appear to be the main function of either cementoin, elafin or full-length pre-elafin/trappin-2 against

  3. Tasco®: A Product of Ascophyllum nodosum Enhances Immune Response of Caenorhabditis elegans Against Pseudomonas aeruginosa Infection

    Directory of Open Access Journals (Sweden)

    Franklin Evans

    2012-01-01

    Full Text Available The effects of Tasco®, a product made from the brown seaweed (Ascophyllum nodosum were tested for the ability to protect Caenorhabditis elegans against Pseudomonas aeruginosa infection. A water extract of Tasco® (TWE reduced P. aeruginosa inflicted mortality in the nematode. The TWE, at a concentration of 300 µg/mL, offered the maximum protection and induced the expression of innate immune response genes viz.; zk6.7 (Lypases, lys-1 (Lysozyme, spp-1 (Saponin like protein, f28d1.3 (Thaumatin like protein, t20g5.7 (Matridin SK domain protein, abf-1 (Antibacterial protein and f38a1.5 (Lectin family protein. Further, TWE treatment also affected a number of virulence components of the P. aeuroginosa and reduced its secreted virulence factors such as lipase, proteases and toxic metabolites; hydrogen cyanide and pyocyanin. Decreased virulence factors were associated with a significant reduction in expression of regulatory genes involved in quorum sensing, lasI, lasR, rhlI and rhlR. In conclusion, the TWE-treatment protected the C. elegans against P. aeruginosa infection by a combination of effects on the innate immunity of the worms and direct effects on the bacterial quorum sensing and virulence factors.

  4. Upregulating Nonneuronal Cholinergic Activity Decreases TNF Release from Lipopolysaccharide-Stimulated RAW264.7 Cells

    Directory of Open Access Journals (Sweden)

    Yi Lv

    2014-01-01

    Full Text Available Nonneuronal cholinergic system plays a primary role in maintaining homeostasis. It has been proved that endogenous neuronal acetylcholine (ACh could play an anti-inflammatory role, and exogenous cholinergic agonists could weaken macrophages inflammatory response to lipopolysaccharide (LPS stimulation through activation of α7 subunit-containing nicotinic acetylcholine receptor (α7nAChR. We assumed that nonneuronal cholinergic system existing in macrophages could modulate inflammation through autocrine ACh and expressed α7nAChR on the cells. Therefore, we explored whether LPS continuous stimulation could upregulate the nonneuronal cholinergic activity in macrophages and whether increasing autocrine ACh could decrease TNF release from the macrophages. The results showed that, in RAW264.7 cells incubated with LPS for 20 hours, the secretion of ACh was significantly decreased at 4 h and then gradually increased, accompanied with the enhancement of α7nAChR expression level. The release of TNF was greatly increased from RAW264.7 cells at 4 h and 8 h exposure to LPS; however, it was suppressed at 20 h. Upregulating choline acetyltransferase (ChAT expression through ChAT gene transfection could enhance ACh secretion and reduce TNF release from the infected RAW264. 7cells. The results indicated that LPS stimulation could modulate the activity of nonneuronal cholinergic system of RAW264.7 cells. Enhancing autocrine ACh production could attenuate TNF release from RAW264.7 cells.

  5. Molecular cloning and functional characterization of a mouse gene upregulated by lipopolysaccharide treatment reveals alternative splicing

    Energy Technology Data Exchange (ETDEWEB)

    Du, Kejun; Chen, Yaoming; Dai, Zongming; Bi, Yuan; Cai, Tongjian [Department of Occupational and Environmental Health, Fourth Military Medical University, Xi' an 710032, Shaanxi Province (China); Hou, Lichao [Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi' an 710032, Shaanxi Province (China); Chai, Yubo; Song, Qinghe; Chen, Sumin [Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi' an 710032, Shaanxi Province (China); Luo, Wenjing, E-mail: luowenj@fmmu.edu.cn [Department of Occupational and Environmental Health, Fourth Military Medical University, Xi' an 710032, Shaanxi Province (China); Chen, Jingyuan, E-mail: jy_chen@fmmu.edu.cn [Department of Occupational and Environmental Health, Fourth Military Medical University, Xi' an 710032, Shaanxi Province (China)

    2010-01-01

    Treatment of mouse cells with lipopolysaccharide (LPS) potently initiates an inflammatory response, but the underlying mechanisms are unclear. We therefore sought to characterize cDNA sequences of a new mouse LPS-responsive gene, and to evaluate the effects of MLrg. Full-length cDNAs were obtained from LPS-treated NIH3T3 cells. We report that the MLrg gene produces two alternative splice products (GenBank Accession Nos. (DQ316984) and (DQ320011)), respectively, encoding MLrgW and MLrgS polypeptides. Both proteins contain zinc finger and leucine zipper domains and are thus potential regulators of transcription. Expression of MLrgW and MLrgS were robustly upregulated following LPS treatment, and the proteins were localized predominantly in the nuclear membrane and cytoplasm. In stable transfectants over-expressing MLrgW the proportion of cells in G1 phase was significantly reduced, while in cells over-expressing MLrgS the proportion of cells in G2 was significantly increased; both proteins are thus potential regulators of cell cycle progression. Upregulation of MLrgW and MLrgS may be an important component of the LPS inflammatory pathway and of the host response to infection with GNB.

  6. Effect of Lipopolysaccharide on Progesterone Production during Luteinization of Granulosa and Theca cells In Vitro.

    Science.gov (United States)

    Shimizu, Takashi; Echizenya, Riku; Miyamoto, Akio

    2016-04-01

    The aim of this study is to examine the effect of lipopolysaccharide (LPS) on progesterone production during luteinization of granulosa and theca cells isolated from bovine large follicles. Granulosa and theca cells isolated from large follicles of bovine ovaries were exposed to LPS under appropriate hormone conditions in vitro. Progesterone (P4) production in theca cells, but not granulosa cells, was decreased by long-term exposure of LPS. Long-term exposure of LPS suppressed the gene expression of luteinizing hormone receptor in theca cells. Although long-term exposure of LPS did not affect the expression of steroidogenic acute regulatory protein (StAR) and 3β-hydroxy-steroid dehydrogenase (3β-HSD) genes, it did inhibit the protein expression of StAR and 3β-HSD in theca cells. These findings suggest that theca cells, rather than granulosa cells, are susceptible to LPS during luteinization and that LPS inhibits P4 production by decreasing protein levels of StAR during luteinization of theca cells. © 2016 Wiley Periodicals, Inc.

  7. Anti-inflammatory activity of fisetin in human gingival fibroblasts treated with lipopolysaccharide.

    Science.gov (United States)

    Gutiérrez-Venegas, Gloria; Contreras-Sánchez, Anabel; Ventura-Arroyo, Jairo Agustín

    2014-10-01

    Fisetin is an anti-inflammatory flavonoid; however, its anti-inflammatory mechanism is not yet understood. In this study, we evaluated the anti-inflammatory effect of fisetin and its association with mitogen-activated protein kinase (MAPK) and nuclear factor kappa-beta pathways in human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS) obtained from Porphyromonas gingivalis. The cell signaling, cell viability, and cyclooxygenase-2 (COX-2) expression of HGFs treated with various concentrations (0, 1, 5, 10, and 15 μM) of fisetin were measured by cell viability assay (MTT), Western blotting, and reverse transcriptase polymerase chain reaction analysis on COX-2. We found that fisetin significantly reduced the synthesis and expression of prostaglandin E2 in HGFs treated with LPS. Activation of extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 MAPK was suppressed consistently by fisetin in HGFs treated with LPS. The data indicate that fisetin inhibits MAPK activation and COX-2 expression without affecting cell viability. These findings may be valuable for understanding the mechanism of the effect of fisetin on periodontal disease.

  8. Role of Muramyl Dipeptide in Lipopolysaccharide-Mediated Biological Activity and Osteoclast Activity

    Directory of Open Access Journals (Sweden)

    Hideki Kitaura

    2018-01-01

    Full Text Available Lipopolysaccharide (LPS is an endotoxin and bacterial cell wall component that is capable of inducing inflammation and immunological activity. Muramyl dipeptide (MDP, the minimal essential structural unit responsible for the immunological activity of peptidoglycans, is another inflammation-inducing molecule that is ubiquitously expressed by bacteria. Several studies have shown that inflammation-related biological activities were synergistically induced by interactions between LPS and MDP. MDP synergistically enhances production of proinflammatory cytokines that are induced by LPS exposure. Injection of MDP induces lethal shock in mice challenged with LPS. LPS also induces osteoclast formation and pathological bone resorption; MDP enhances LPS induction of both processes. Furthermore, MDP enhances the LPS-induced receptor activator of NF-κB ligand (RANKL expression and toll-like receptor 4 (TLR4 expression both in vivo and in vitro. Additionally, MDP enhances LPS-induced mitogen-activated protein kinase (MAPK signaling in stromal cells. Taken together, these findings suggest that MDP plays an important role in LPS-induced biological activities. This review discusses the role of MDP in LPS-mediated biological activities, primarily in relation to osteoclastogenesis.

  9. Influence of Pseudomonas aeruginosa on exacerbation in patients with bronchiectasis

    Directory of Open Access Journals (Sweden)

    Kiran Chawla

    2015-01-01

    Full Text Available Background: A majority of the studies done on the western population have shown that Pseudomonas aeruginosa causes many severe infections in patients with bronchiectasis as compared to other pathogens. There is scarcity of similar data from the Asian population. Materials and Methods: A prospective study was undertaken to identify the various pathogens isolated from the respiratory samples of 117 patients with bronchiectasis from south India and to compare the clinicomicrobiological profile of infections caused by P. aeruginosa and other respiratory pathogens. Results: The respiratory pathogens were isolated from 63 (53.8% patients. P. aeruginosa was the most common isolate (46.0% followed by Klebsiella pneumoniae (14.3% and other pathogenic bacteria. Patients included in the P. aeruginosa group had a higher number of exacerbations (p: 0.008, greater number of hospital admissions (p: 0.007, a prolonged hospital stay (p: 0.03, and poor lung function, compared to the patients infected with the non-Pseudomonas group. Conclusion: It is necessary to investigate the etiology of respiratory tract infections among bronchiectasis patients followed by the prompt management of cases diagnosed with P. aeruginosa infections, so as to lower the morbidity and have a better prognosis.

  10. Balneotherapy is a potential risk factor for Pseudomonas aeruginosa colonization

    Directory of Open Access Journals (Sweden)

    Gabriela Deutsch

    Full Text Available ABSTRACT The practice of immersion in burn patient has been abandoned in many parts of the world but in Brazil it is still common. The aim of this study was to ascertain if balneotherapy is a risk factor for Pseudomonas aeruginosa colonization in thermally injured patients. Eighteen patients from a Burn Center were studied for 14 weeks for Pseudomonas aeruginosa. Samples were collected by swabbing the exudate of wounds, before and after giving bath to the patients and from balneotherapy table. Pulsed-field gel electrophoresis was used to determine bacterial genetic relatedness. Thirty-seven P. aeruginosa isolates were detected from 292 swabs collected from patients' burn surface area and from the balneotherapy table. Profile analysis of P. aeruginosa DNA fragmentation showed 10 clones among the 37 strains analyzed. Type A is the most prevalent clone, with 23 strains distributed into eight subtypes. These were present in the swabs collected, before and after the patients' bath, from the surface of the bath table, suggesting that there was cross-contamination between the patients in different ways. This work demonstrates that balneotherapy is a risk factor in the Burn Center studied, because the same clone was found among P. aeruginosa isolates collected at various points and times.

  11. Bacteriophage Infectivity Against Pseudomonas aeruginosa in Saline Conditions

    KAUST Repository

    Scarascia, Giantommaso

    2018-05-02

    Pseudomonas aeruginosa is a ubiquitous member of marine biofilm, and reduces thiosulfate to produce toxic hydrogen sulfide gas. In this study, lytic bacteriophages were isolated and applied to inhibit the growth of P. aeruginosa in planktonic mode at different temperature, pH, and salinity. Bacteriophages showed optimal infectivity at a multiplicity of infection of 10 in saline conditions, and demonstrated lytic abilities over all tested temperature (25, 30, 37, and 45°C) and pH 6–9. Planktonic P. aeruginosa exhibited significantly longer lag phase and lower specific growth rates upon exposure to bacteriophages. Bacteriophages were subsequently applied to P. aeruginosa-enriched biofilm and were determined to lower the relative abundance of Pseudomonas-related taxa from 0.17 to 5.58% in controls to 0.01–0.61% in treated microbial communities. The relative abundance of Alphaproteobacteria, Pseudoalteromonas, and Planococcaceae decreased, possibly due to the phage-induced disruption of the biofilm matrix. Lastly, when applied to mitigate biofouling of ultrafiltration membranes, bacteriophages were determined to reduce the transmembrane pressure increase by 18% when utilized alone, and by 49% when used in combination with citric acid. The combined treatment was more effective compared with the citric acid treatment alone, which reported ca. 30% transmembrane pressure reduction. Collectively, the findings demonstrated that bacteriophages can be used as a biocidal agent to mitigate undesirable P. aeruginosa-associated problems in seawater applications.

  12. Effects of lidocaine on lipopolysaccharide-induced synovitis in horses

    OpenAIRE

    Campebell,R.C.; Peiró,J.R.; Valadão,C.A.A.; Santana,A.E.; Cunha,F.Q.

    2004-01-01

    Lidocaine (100mg 2%) injected into the carpal joint was used to evaluate the inflammatory response induced by injection (1.5ng) of intra-articular E. coli lipopolysaccharide (LPS) endotoxin. Seventeen male Mangalarga horses aged two to three years were divided into three groups and in all animals was injected 0.9% saline (SAL) in the left carpus (LC), and in the right carpus (RC) one of the following combinations were injected: group A (n=6) LPS plus SAL; group B (n=6) LPS plus lidocaine; gro...

  13. Recruitment of mitochondrial uncoupling protein UCP2 after lipopolysaccharide induction

    Czech Academy of Sciences Publication Activity Database

    Růžička, Michal; Škobisová, Eva; Dlasková, Andrea; Šantorová, Jitka; Smolková, Katarína; Špaček, Tomáš; Žáčková, Markéta; Modrianský, M.; Ježek, Petr

    2005-01-01

    Roč. 37, č. 4 (2005), s. 809-821 ISSN 1357-2725 R&D Projects: GA ČR(CZ) GA301/02/1215; GA ČR(CZ) GP301/01/P084; GA AV ČR(CZ) IAA5011106 Grant - others:NIH(US) TW01487 Institutional research plan: CEZ:AV0Z5011922 Keywords : lipopolysaccharide * oxidative stress in liver * mitochondrial uncoupling protein UCP2 Subject RIV: CE - Biochemistry Impact factor: 3.871, year: 2005

  14. Preparation and characterization of a radioiodinated bacterial lipopolysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Ulevitch, R J [Scripps Clinic and Research Foundation, La Jolla, Calif. (USA)

    1978-03-01

    Radioiodinated lipopolysaccharide (LPS) from E.coli 0111:B4 has been prepared by reacting p-OH methylbenzimidate with 0111:B4 LPS at alkaline pH. The resulting LPS derivative has been radiolabeled with Na/sup 125/I. Specific activities of up to 5..mu..Ci/..mu..g LPS may be obtained by this technique and significantly the preparation of the radioiodinated LPS does not alter the biophysical, immunologic or biologic properties of 0111:B4 LPS. The methods described here are applicable to any 'protein free' LPS preparation containing primary amino groups.

  15. Molecular detection of an atypical, highly resistant, clonal Pseudomonas aeruginosa isolate in cystic fibrosis patients.

    LENUS (Irish Health Repository)

    Keating, Deirdre

    2013-03-01

    The identification of Pseudomonas aeruginosa (P. aeruginosa) isolates in sputum from cystic fibrosis (CF) patients can be challenging due to the multitude of phenotypic changes isolates undergo during adaptation to the microenvironment of the CF lung.

  16. Activity of Bacteriophages in Removing Biofilms of Pseudomonas aeruginosa Isolates from Chronic Rhinosinusitis Patients

    NARCIS (Netherlands)

    Fong, Stephanie A.; Drilling, Amanda; Morales, Sandra; Cornet, Marjolein E.; Woodworth, Bradford A.; Fokkens, Wytske J.; Psaltis, Alkis J.; Vreugde, Sarah; Wormald, Peter-John

    2017-01-01

    Introduction:Pseudomonas aeruginosa infections are prevalent amongst chronic rhinosinusitis (CRS) sufferers. Many P. aeruginosa strains form biofilms, leading to treatment failure. Lytic bacteriophages (phages) are viruses that infect, replicate within, and lyse bacteria, causing bacterial death.

  17. Initial Pseudomonas aeruginosa infection in patients with cystic fibrosis: characteristics of eradicated and persistent isolates

    DEFF Research Database (Denmark)

    Tramper-Stranders, G. A.; van der Ent, C. K.; Molin, Søren

    2012-01-01

    Clin Microbiol Infect 2012; 18: 567574 Abstract Despite intensive eradication therapy, some CF patients with early Pseudomonas aeruginosa infection rapidly develop a chronic infection. To elucidate factors associated with this persistence, bacterial characteristics of early P. aeruginosa isolates...

  18. Archetypal analysis of diverse Pseudomonas aeruginosa transcriptomes reveals adaptation in cystic fibrosis airways

    Science.gov (United States)

    2013-01-01

    Background Analysis of global gene expression by DNA microarrays is widely used in experimental molecular biology. However, the complexity of such high-dimensional data sets makes it difficult to fully understand the underlying biological features present in the data. The aim of this study is to introduce a method for DNA microarray analysis that provides an intuitive interpretation of data through dimension reduction and pattern recognition. We present the first “Archetypal Analysis” of global gene expression. The analysis is based on microarray data from five integrated studies of Pseudomonas aeruginosa isolated from the airways of cystic fibrosis patients. Results Our analysis clustered samples into distinct groups with comprehensible characteristics since the archetypes representing the individual groups are closely related to samples present in the data set. Significant changes in gene expression between different groups identified adaptive changes of the bacteria residing in the cystic fibrosis lung. The analysis suggests a similar gene expression pattern between isolates with a high mutation rate (hypermutators) despite accumulation of different mutations for these isolates. This suggests positive selection in the cystic fibrosis lung environment, and changes in gene expression for these isolates are therefore most likely related to adaptation of the bacteria. Conclusions Archetypal analysis succeeded in identifying adaptive changes of P. aeruginosa. The combination of clustering and matrix factorization made it possible to reveal minor similarities among different groups of data, which other analytical methods failed to identify. We suggest that this analysis could be used to supplement current methods used to analyze DNA microarray data. PMID:24059747

  19. Amikacin loaded PLGA nanoparticles against Pseudomonas aeruginosa.

    Science.gov (United States)

    Sabaeifard, Parastoo; Abdi-Ali, Ahya; Soudi, Mohammad Reza; Gamazo, Carlos; Irache, Juan Manuel

    2016-10-10

    Amikacin is a very effective aminoglycoside antibiotic but according to its high toxicity, the use of this antibiotic has been limited. The aim of this study was to formulate and characterize amikacin loaded PLGA nanoparticles. Nanoparticles were synthetized using a solid-in-oil-in-water emulsion technique with different ratio of PLGA 50:50 (Resomer 502H) to drug (100:3.5, 80:3.5 and 60:3.5), two different concentrations of stabilizer (pluronic F68) (0.5% or 1%) and varied g forces to recover the final products. The most efficient formulation based on drug loading (26.0±1.3μg/mg nanoparticle) and encapsulation efficiency (76.8±3.8%) was the one obtained with 100:3.5 PLGA:drug and 0.5% luronic F68, recovered by 20,000×g for 20min. Drug release kinetic study indicated that about 50% of the encapsulated drug was released during the first hour of incubation in phospahte buffer, pH7.4, 37°C, 120rpm. Using different cell viability/cytotoxicity assays, the optimized formulation showed no toxicity against RAW macrophages after 2 and 24h of exposure. Furthermore, released drug was active and maintained its bactericidal activity against Pseudomonas aeruginosa in vitro. These results support the effective utilization of the PLGA nanoparticle formulation for amikacin in further in vivo studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Cordycepin alleviates lipopolysaccharide-induced acute lung injury via Nrf2/HO-1 pathway.

    Science.gov (United States)

    Qing, Rui; Huang, Zezhi; Tang, Yufei; Xiang, Qingke; Yang, Fan

    2018-04-24

    The present study is to investigate the protective effect of cordycepin on inflammatory reactions in rats with acute lung injury (ALI) induced by lipopolysaccharide (LPS), as well as the underlying mechanism. Wistar rat model of ALI was induced by intravenous injection of LPS (30 mg/kg body weight). One hour later, intravenous injection of cordycepin (1, 10 or 30 mg/kg body weight) was administered. The wet-to-dry weight ratio of lung tissues and myeloperoxidase activity in the lung tissues were measured. The contents of nitrite and nitrate were measured by reduction method, while chemiluminescence was used to determine the content of superoxide. Quantitative real-time polymerase chain reaction and Western blotting were used to determine the expression of mRNA and protein, respectively. Colorimetry was performed to determine the enzymatic activity of heme oxygenase-1 (HO-1). Nuclear translocation of Nrf2 was identified by Western blotting. The plasma contents of cytokines were measured by enzyme-linked immunosorbent assay. Cordycepin enhanced the expression and enzymatic activity of HO-1 in ALI rats, and activated Nrf2 by inducing the translocation of Nrf2 from cytoplasm to nucleus. In addition, cordycepin regulated the secretion of TNF-α, IL-6 and IL-10 via HO-1, and suppressed inflammation in lung tissues of ALI rats by inducing the expression of HO-1. HO-1 played important roles in the down-regulation of superoxide levels in lung tissues by cordycepin, and HO-1 expression induced by cordycepin affected nitrite and nitrate concentrations in plasma and iNOS protein expression in lung tissues. Cordycepin showed protective effect on injuries in lung tissues. The present study demonstrates that cordycepin alleviates inflammation induced by LPS via the activation of Nrf2 and up-regulation of HO-1 expression. Copyright © 2018. Published by Elsevier B.V.

  1. Involvement of interleukin‑23 induced by Porphyromonas endodontalis lipopolysaccharide in osteoclastogenesis.

    Science.gov (United States)

    Ma, Nan; Yang, Di; Okamura, Hirohiko; Teramachi, Jumpei; Hasegawa, Tomokazu; Qiu, Lihong; Haneji, Tatsuji

    2017-02-01

    Periapical lesions are characterized by the destruction of periapical bone, and occur as a result of local inflammatory responses to root canal infection by microorganisms including Porphyromonas endodontalis (P. endodontalis). P. endodontalis and its primary virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical lesions and alveolar bone loss. Interleukin‑23 (IL‑23) is critical in the initiation and progression of periodontal disease via effects on peripheral bone metabolism. The present study investigated the expression of IL‑23 in tissue where a periapical lesion was present, and the effect of P. endodontalis LPS on the expression of IL‑23 in periodontal ligament (PDL) cells. Reverse transcription‑ quantitative polymerase chain reaction and immunohistochemistry revealed increased levels of IL‑23 expression in tissue with periapical lesions compared with healthy PDL tissue. Treatment with P. endodontalis LPS increased the expression of IL‑23 in the SH‑9 human PDL cell line. BAY11‑7082, a nuclear factor κB inhibitor, suppressed P. endodontalis LPS‑induced IL‑23 expression in SH‑9 cells. Treatment of RAW264.7 cells with conditioned medium from P. endodontalis LPS‑treated SH‑9 cells promoted osteoclastogenesis. By contrast, RAW264.7 cells treated with conditioned medium from IL‑23‑knockdown SH‑9 cells underwent reduced levels of osteoclastogenesis. The results of the present study indicated that the expression of IL‑23 in PDL cells induced by P. endodontalis LPS treatment may be involved in the progression of periapical lesions via stimulation of the osteoclastogenesis process.

  2. Involvement of interleukin-23 induced by Porphyromonas endodontalis lipopolysaccharide in osteoclastogenesis

    Science.gov (United States)

    Ma, Nan; Yang, Di; Okamura, Hirohiko; Teramachi, Jumpei; Hasegawa, Tomokazu; Qiu, Lihong; Haneji, Tatsuji

    2017-01-01

    Periapical lesions are characterized by the destruction of periapical bone, and occur as a result of local inflammatory responses to root canal infection by microorganisms including Porphyromonas endodontalis (P. endodontalis). P. endodontalis and its primary virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical lesions and alveolar bone loss. Interleukin-23 (IL-23) is critical in the initiation and progression of periodontal disease via effects on peripheral bone metabolism. The present study investigated the expression of IL-23 in tissue where a periapical lesion was present, and the effect of P. endodontalis LPS on the expression of IL-23 in periodontal ligament (PDL) cells. Reverse transcription- quantitative polymerase chain reaction and immunohistochemistry revealed increased levels of IL-23 expression in tissue with periapical lesions compared with healthy PDL tissue. Treatment with P. endodontalis LPS increased the expression of IL-23 in the SH-9 human PDL cell line. BAY11-7082, a nuclear factor κB inhibitor, suppressed P. endodontalis LPS-induced IL-23 expression in SH-9 cells. Treatment of RAW264.7 cells with conditioned medium from P. endodontalis LPS-treated SH-9 cells promoted osteoclastogenesis. By contrast, RAW264.7 cells treated with conditioned medium from IL-23-knockdown SH-9 cells underwent reduced levels of osteoclastogenesis. The results of the present study indicated that the expression of IL-23 in PDL cells induced by P. endodontalis LPS treatment may be involved in the progression of periapical lesions via stimulation of the osteoclastogenesis process. PMID:28000855

  3. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites.

    Science.gov (United States)

    Colmer-Hamood, J A; Dzvova, N; Kruczek, C; Hamood, A N

    2016-01-01

    Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen.

    Directory of Open Access Journals (Sweden)

    Anthony Arnoldo

    2008-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibitors that can suppress the toxicity caused by heterologous expression of selected Pseudomonas aeruginosa ORFs. We identified the first small molecule inhibitor of Exoenzyme S (ExoS, a toxin involved in Type III secretion. We show that this inhibitor, exosin, modulates ExoS ADP-ribosyltransferase activity in vitro, suggesting the inhibition is direct. Moreover, exosin and two of its analogues display a significant protective effect against Pseudomonas infection in vivo. Furthermore, because the assay was performed in yeast, we were able to demonstrate that several yeast homologues of the known human ExoS targets are likely ADP-ribosylated by the toxin. For example, using an in vitro enzymatic assay, we demonstrate that yeast Ras2p is directly modified by ExoS. Lastly, by surveying a collection of yeast deletion mutants, we identified Bmh1p, a yeast homologue of the human FAS, as an ExoS cofactor, revealing that portions of the bacterial toxin mode of action are conserved from yeast to human. Taken together, our integrated cell-based, chemical-genetic approach demonstrates that such screens can augment traditional drug screening approaches and facilitate the discovery of new compounds against a broad range of human pathogens.

  5. Carbapenem-resistant-only Pseudomonas aeruginosa infection in patients formerly infected by carbapenem-susceptible strains.

    Science.gov (United States)

    Tsai, Ming-Han; Wu, Tsu-Lan; Su, Lin-Hui; Lo, Wei-Lin; Chen, Chyi-Liang; Liang, Yi-Hua; Chiu, Cheng-Hsun

    2014-12-01

    Pseudomonas aeruginosa isolates that were initially carbapenem-susceptible and later became selective carbapenem-resistant following antimicrobial therapy were identified from individual cases during the same hospitalisation. Cross-resistance to other β-lactams was not found and their susceptibilities remained identical in consecutive isolates. Real-time quantitative reverse transcription PCR was performed to investigate the role of OprD, an outer membrane protein regulating the entry of carbapenems, in the appearance of carbapenem-resistant-only P. aeruginosa (CROPA). Fifteen paired isolates of carbapenem-susceptible P. aeruginosa (CS-PA) and CROPA were identified. All of the cases had carbapenem exposure history within 1 month before the appearance of CROPA (mean 10 days). Reduced OprD expression was found in 93% (14/15) of the isolates, suggesting that oprD inactivation was the major contributor to selective carbapenem resistance. Of the 14 cases with CROPA due to oprD mutation, 71% (10/14) were persistent infection, as genotype analysis revealed that their paired strains were isogenic; 29% (4/14) represented re-infections as they were heterogenic, suggesting that oprD-deficient CROPA existed in the hospital and that carbapenem selective pressure promoted its spread to patients. We conclude that CROPA may occur soon after the use of carbapenems to treat CS-PA infections and that oprD mutation is the major mechanism of resistance in CROPA. Restriction of empirical use of carbapenems by antibiotic stewardship is important to halt the occurrence of CROPA. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  6. Antimicrobial Effects of β-Lactams on Imipenem-Resistant Ceftazidime-Susceptible Pseudomonas aeruginosa.

    Science.gov (United States)

    Wi, Yu Mi; Choi, Ji-Young; Lee, Ji-Young; Kang, Cheol-In; Chung, Doo Ryeon; Peck, Kyong Ran; Song, Jae-Hoon; Ko, Kwan Soo

    2017-06-01

    We studied the resistance mechanism and antimicrobial effects of β-lactams on imipenem-resistant Pseudomonas aeruginosa isolates that were susceptible to ceftazidime as detected by time-kill curve methods. Among 215 P. aeruginosa isolates from hospitalized patients in eight hospitals in the Republic of Korea, 18 isolates (23.4% of 77 imipenem-resistant isolates) were imipenem resistant and ceftazidime susceptible. Multilocus sequence typing revealed diverse genotypes, which indicated independent emergence. These 18 isolates were negative for carbapenemase genes. All 18 imipenem-resistant ceftazidime-susceptible isolates showed decreased mRNA expression of oprD , and overexpression of mexB was observed in 13 isolates. In contrast, overexpression of ampC , mexD , mexF , or mexY was rarely found. Time-kill curve methods were applied to three selected imipenem-resistant ceftazidime-susceptible isolates at a standard inoculum (5 × 10 5 CFU/ml) or at a high inoculum (5 × 10 7 CFU/ml) to evaluate the antimicrobial effects of β-lactams. Inoculum effects were detected for all three β-lactam antibiotics, ceftazidime, cefepime, and piperacillin-tazobactam, against all three isolates. The antibiotics had significant killing effects in the standard inoculum, but no effects in the high inoculum were observed. Our results suggest that β-lactam antibiotics should be used with caution in patients with imipenem-resistant ceftazidime-susceptible P. aeruginosa infection, especially in high-inoculum infections such as endocarditis and osteomyelitis. Copyright © 2017 American Society for Microbiology.

  7. A Marine Actinomycete Rescues Caenorhabditis elegans from Pseudomonas aeruginosa Infection through Restitution of Lysozyme 7

    Directory of Open Access Journals (Sweden)

    Siti N. Fatin

    2017-11-01

    Full Text Available The resistance of Pseudomonas aeruginosa to conventional antimicrobial treatment is a major scourge in healthcare. Therefore, it is crucial that novel potent anti-infectives are discovered. The aim of the present study is to screen marine actinomycetes for chemical entities capable of overcoming P. aeruginosa infection through mechanisms involving anti-virulence or host immunity activities. A total of 18 actinomycetes isolates were sampled from marine sediment of Songsong Island, Kedah, Malaysia. Upon confirming that the methanolic crude extract of these isolates do not display direct bactericidal activities, they were tested for capacity to rescue Caenorhabditis elegans infected with P. aeruginosa strain PA14. A hexane partition of the extract from one isolate, designated as Streptomyces sp. CCB-PSK207, could promote the survival of PA14 infected worms by more than 60%. Partial 16S sequence analysis on this isolate showed identity of 99.79% with Streptomyces sundarbansensis. This partition did not impair feeding behavior of C. elegans worms. Tested on PA14, the partition also did not affect bacterial growth or its ability to colonize host gut. The production of biofilm, protease, and pyocyanin in PA14 were uninterrupted, although there was an increase in elastase production. In lys-7::GFP worms, this partition was shown to induce the expression of lysozyme 7, an important innate immunity defense molecule that was repressed during PA14 infection. GC-MS analysis of the bioactive fraction of Streptomyces sp. CCB-PSK207 revealed the presence of methyl esters of branched saturated fatty acids. In conclusion, this is the first report of a marine actinomycete producing metabolites capable of rescuing C. elegans from PA14 through a lys-7 mediated activity.

  8. Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.

    Directory of Open Access Journals (Sweden)

    Jing Luo

    Full Text Available The quorum sensing (QS circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed

  9. Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.

    Science.gov (United States)

    Lee, Keehoon; Yoon, Sang Sun

    2017-06-28

    A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. Pseudomonas aeruginosa is a bacterium known to produce robust biofilms. P. aeruginosa biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of P. aeruginosa biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species ( i.e. , multispecies biofilms) are discussed in detail.

  10. Hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Salomonsen, Charlotte Mark

    research has been performed in this field and most published work is more than 25 years old. The studies presented in this thesis aim at elucidating varying aspects of the disease: Article I investigates the relationships of P. aeruginosa isolated from mink hemorrhagic pneumonia using pulsed field gel...... electrophoresis (PFGE) and a commercial typing system based on single nucleotide polymorphisms (SNP) on chosen strains. The results presented in this article show that 70% of P. aeruginosa isolated from outbreaks of hemorrhagic pneumonia in mink consist of unique strains, while the remaining 30% belongs to either...... in hemorrhagic pneumonia caused by P. aeruginosa and E. coli in diagnostic material. The distribution of the two pathogens is visualized using fluorescence in situ hybridization (FISH). Two histological patterns were observed in the work presented in Article II; one was very hemorrhagic with few bacteria while...

  11. Outbreak of Pseudomonas aeruginosa bacteraemia in a haematology department

    DEFF Research Database (Denmark)

    Rasmussen, Benjamin Schnack; Christensen, Nikolas; Sørensen, Jan

    2015-01-01

    the outbreak and 12 months later. The audits were conducted by the method of direct observation. RESULTS: Several PFGE types were involved with no clear association to isolates from environmental samples. The audit revealed poor hygiene related to the handling of central venous catheters. After optimising......INTRODUCTION: Infection by Pseudomonas aeruginosa represents a major cause of morbidity and mortality among immunocompromised patients. In Denmark, an increase in P. aeruginosa isolates from blood cultures from a haematology department prompted a hygienic audit in 2007. METHODS: Blood cultures...... catheter hygiene, the number of P. aeruginosa bacteraemia cases fell significantly. CONCLUSION: Since no clear association between patient and environmental genotype was established, it was suspected that central venous catheters were the main portal of entry. This was further supported by a simultaneous...

  12. Extracellular DNA Shields against Aminoglycosides in Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Nilsson, Martin; Jensen, Peter Østrup

    2013-01-01

    Within recent years, it has been established that extracellular DNA is a key constituent of the matrix of microbial biofilms. In addition, it has recently been demonstrated that DNA binds positively charged antimicrobials such as aminoglycosides and antimicrobial peptides. In the present study, we...... provide evidence that extracellular DNA shields against aminoglycosides in Pseudomonas aeruginosa biofilms. We show that exogenously supplemented DNA integrates into P. aeruginosa biofilms and increases their tolerance toward aminoglycosides. We provide evidence that biofilms formed by a DNA release......-deficient P. aeruginosa quorum-sensing mutant are more susceptible to aminoglycoside treatment than wild-type biofilms but become rescued from the detrimental action of aminoglycosides upon supplementation with exogenous DNA. Furthermore, we demonstrate that exposure to lysed polymorphonuclear leukocytes...

  13. Effects of antibiotics on quorum sensing in pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena; Alhede, Morten; Phipps, Richard Kerry

    2008-01-01

    in animal infection models. Treatment of cystic fibrosis (CF) patients chronically infected with P. aeruginosa with the macrolide antibiotic azithromycin (AZM) has been demonstrated to improve the clinical outcome. Several studies indicate that AZM may accomplish its beneficial action in CF patients....... Three of the antibiotics tested, AZM, ceftazidime (CFT), and ciprofloxacin (CPR), were very active in the assay and were further examined for their effects on QS-regulated virulence factor production in P. aeruginosa. The effects of the three antibiotics administered at subinhibitory concentrations were...... by impeding QS, thereby reducing the pathogenicity of P. aeruginosa. This led us to investigate whether QS inhibition is a common feature of antibiotics. We present the results of a screening of 12 antibiotics for their QS-inhibitory activities using a previously described QS inhibitor selector 1 strain...

  14. Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

    Science.gov (United States)

    Kirienko, Natalia V; Cezairliyan, Brent O; Ausubel, Frederick M; Powell, Jennifer R

    2014-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the interaction between bacterial pathogens such as Pseudomonas aeruginosa and the metazoan innate immune system. Powerful genetic and molecular tools in both C. elegans and P. aeruginosa facilitate the identification and analysis of bacterial virulence factors as well as host defense factors. Here we describe three different assays that use the C. elegans-P. aeruginosa strain PA14 host-pathogen system. Fast Killing is a toxin-mediated death that depends on a diffusible toxin produced by PA14 but not on live bacteria. Slow Killing is due to an active infection in which bacteria colonize the C. elegans intestinal lumen. Liquid Killing is designed for high-throughput screening of chemical libraries for anti-infective compounds. Each assay has unique features and, interestingly, the PA14 virulence factors involved in killing are different in each assay.

  15. Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

    Directory of Open Access Journals (Sweden)

    Aoyama Naoki

    2010-11-01

    Full Text Available Abstract Background Chinchillas (Chinchilla laniger are popular as pets and are often used as laboratory animals for various studies. Pseudomonas aeruginosa is a major infectious agent that causes otitis media, pneumonia, septicaemia enteritis, and sudden death in chinchillas. This bacterium is also a leading cause of nosocomial infections in humans. To prevent propagation of P. aeruginosa infection among humans and animals, detailed characteristics of the isolates, including antibiotic susceptibility and genetic features, are needed. In this study, we surveyed P. aeruginosa distribution in chinchillas bred as pets or laboratory animals. We also characterized the isolates from these chinchillas by testing for antibiotic susceptibility and by gene analysis. Results P. aeruginosa was isolated from 41.8% of the 67 chinchillas included in the study. Slide agglutination and pulsed-field gel electrophoresis discriminated 5 serotypes and 7 unique patterns, respectively. For the antibiotic susceptibility test, 40.9% of isolates were susceptible to gentamicin, 77.3% to ciprofloxacin, 77.3% to imipenem, and 72.7% to ceftazidime. DNA analyses confirmed that none of the isolates contained the gene encoding extended-spectrum β-lactamases; however, 2 of the total 23 isolates were found to have a gene similar to the pilL gene that has been identified in the pathogenicity island of a clinical isolate of P. aeruginosa. Conclusions P. aeruginosa is widely spread in chinchillas, including strains with reduced susceptibility to the antibiotics and highly virulent strains. The periodic monitoring should be performed to help prevent the propagation of this pathogen and reduce the risk of infection from chinchillas to humans.

  16. Pseudomonas aeruginosa keratitis: outcomes and response to corticosteroid treatment.

    Science.gov (United States)

    Sy, Aileen; Srinivasan, Muthiah; Mascarenhas, Jeena; Lalitha, Prajna; Rajaraman, Revathi; Ravindran, Meenakshi; Oldenburg, Catherine E; Ray, Kathryn J; Glidden, David; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

    2012-01-25

    To compare the clinical course and effect of adjunctive corticosteroid therapy in Pseudomonas aeruginosa with those of all other strains of bacterial keratitis. Subanalyses were performed on data collected in the Steroids for Corneal Ulcers Trial (SCUT), a large randomized controlled trial in which patients were treated with moxifloxacin and were randomly assigned to 1 of 2 adjunctive treatment arms: corticosteroid or placebo (4 times a day with subsequent reduction). Multivariate analysis was used to determine the effect of predictors, organism, and treatment on outcomes, 3-month best-spectacle-corrected visual acuity (BSCVA), and infiltrate/scar size. The incidence of adverse events over a 3-month follow-up period was compared using Fisher's exact test. SCUT enrolled 500 patients. One hundred ten patients had P. aeruginosa ulcers; 99 of 110 (90%) enrolled patients returned for follow-up at 3 months. Patients with P. aeruginosa ulcers had significantly worse visual acuities than patients with other bacterial ulcers (P = 0.001) but showed significantly more improvement in 3-month BSCVA than those with other bacterial ulcers, adjusting for baseline characteristics (-0.14 logMAR; 95% confidence interval, -0.23 to -0.04; P = 0.004). There was no significant difference in adverse events between P. aeruginosa and other bacterial ulcers. There were no significant differences in BSCVA (P = 0.69), infiltrate/scar size (P = 0.17), and incidence of adverse events between patients with P. aeruginosa ulcers treated with adjunctive corticosteroids and patients given placebo. Although P. aeruginosa corneal ulcers have a more severe presentation, they appear to respond better to treatment than other bacterial ulcers. The authors did not find a significant benefit with corticosteroid treatment, but they also did not find any increase in adverse events. (ClinicalTrials.gov number, NCT00324168.).

  17. A case of failed eradication of cystic fibrosis-related sinus colonisation by Pseudomonas aeruginosa.

    LENUS (Irish Health Repository)

    Linnane, Barry

    2015-10-01

    Pseudomonas aeruginosa is a pathogen associated with cystic fibrosis that has potential to decrease lung function and cause respiratory failure. Paranasal sinuses are increasingly recognised as potential reservoirs for intermittent colonisation by P. aeruginosa. This case documents investigation and outcome of P. aeruginosa recurrence in a male paediatric patient over an eight year period.

  18. Ultraviolet-B lethal damage on Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Degiorgi, C.F.; Fernandez, R.O.; Pizarro, R.A.

    1996-01-01

    Pseudomonas aeruginosa has shown an increased sensitivity compared with that of Escherichia coli and Enterobacter cloacae, when they were exposed to 0.4 kJ/m2 of ultraviolet-B radiation. The rapid decay in cell viability observed in Pseudomonas aeruginosa after the irradiation was influenced by factors such as culture media and the presence of pyocyanine during the irradiation. The radioinduced lethal damage could be prevented by photoreactivating treatment, indicating that pyrimidine dimer formation was the mechanism causing bacterial death. The results indicate that several environmental conditions may act as protective agents against ultraviolet-B-induced damage

  19. Bioleaching of copper oxide ore by Pseudomonas aeruginosa

    Science.gov (United States)

    Shabani, M. A.; Irannajad, M.; Azadmehr, A. R.; Meshkini, M.

    2013-12-01

    Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bacterium that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows: particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1:80. Under these conditions, 53% of copper was extracted.

  20. Valproic acid potentiates curcumin-mediated neuroprotection in Lipopolysaccharide induced rats

    Directory of Open Access Journals (Sweden)

    Amira eZaky

    2014-10-01

    Full Text Available The etiology of neuroinflammation is complex and comprises multifactorial, involving both genetic and environmental factors during which diverse genetic and epigenetic modulations are implicated. Curcumin (Cur, and valproic acid (VPA, histone deacetylase 1 inhibitor, have neuroprotective effects. The present study was designed with an aim to investigate the ability of co-treatment of both compounds (Cur or VPA (200mg/kg for four weeks to augment neuroprotection and enhance brain recovery from intra-peritoneal (IP injection of (250 µg/kg lipopolysaccharide (LPS-stimulated neuroinflammatory condition on rat brain cortex. Cortex activation and the effects of combined treatment and production of proinflammatory mediators, COX-2, APE1 and nitric oxide/iNOS were investigated. Neuroinflammation development was assessed by histological analyses and by investigating associated indices (BACE1, APP, PSEN-1 and PSEN-2. Furthermore we measured the expression profile of let-7 miRNAs members a, b, c, e and f in all groups, a highly abundant regulator of gene expression in the CNS. Protein and mRNA levels of neuroinflammation markers COX-2, BACE1, APP and iNOS were also attenuated by combined therapy. On the other hand, assessment of the indicated five let-7 members, showed distinct expression profile pattern in the different groups. Let-7 a, b and c disappeared in the induced group, an effect that was partially suppressed by co-addition of either Cur or VPA. These data suggest that the combined treatment induced significantly the expression of the five members when compared to rats treated with Cur or VPA only as well as to self-recovery group, which indicates a possible benefit from the synergistic effect of Cur-VPA combination as therapeutic agents for neuroinflammation and its associated disorders. The mechanism elucidated here highlights the particular drug-induced expression profile of let-7 family as new targets for future pharmacological development.

  1. CPEB1 modulates lipopolysaccharide-mediated iNOS induction in rat primary astrocytes

    International Nuclear Information System (INIS)

    Kim, Ki Chan; Hyun Joo, So; Shin, Chan Young

    2011-01-01

    Highlights: → Expression and phosphorylation of CPEB1 is increased by LPS stimulation in rat primary astrocytes. → JNK regulates expression and phosphorylation of CPEB1 in reactive astrocytes. → Down-regulation of CPEB1 using siRNA inhibits oxidative stress and iNOS induction by LPS stimulation. → CPEB1 may play an important role in regulating inflammatory responses in reactive astrocytes induced by LPS. -- Abstract: Upon CNS damage, astrocytes undergo a series of biological changes including increased proliferation, production of inflammatory mediators and morphological changes, in a response collectively called reactive gliosis. This process is an essential part of the brains response to injury, yet much is unknown about the molecular mechanism(s) that induce these changes. In this study, we investigated the role of cytoplasmic polyadenylation element binding protein 1 (CPEB1) in the regulation of inflammatory responses in a model of reactive gliosis, lipopolysaccharide-stimulated astrocytes. CPEB1 is an mRNA-binding protein recently shown to be expressed in astrocytes that may play a role in astrocytes migration. After LPS stimulation, the expression and phosphorylation of CPEB1 was increased in rat primary astrocytes in a JNK-dependent process. siRNA-induced knockdown of CPEB1 expression inhibited the LPS-induced up-regulation of iNOS as well as NO and ROS production, a hallmark of immunological activation of astrocytes. The results from the study suggest that CPEB1 is actively involved in the regulation of inflammatory responses in astrocytes, which might provide new insights into the regulatory mechanism after brain injury.

  2. Modulation of lipopolysaccharide-induced chorioamnionitis by Ureaplasma parvum in sheep.

    Science.gov (United States)

    Snyder, Candice C; Wolfe, Katherine B; Gisslen, Tate; Knox, Christine L; Kemp, Matthew W; Kramer, Boris W; Newnham, John P; Jobe, Alan H; Kallapur, Suhas G

    2013-05-01

    Ureaplasma colonization in the setting of polymicrobial flora is common in women with chorioamnionitis, and is a risk factor for preterm delivery and neonatal morbidity. We hypothesized that Ureaplasma colonization of amniotic fluid would modulate chorioamnionitis induced by Escherichia coli lipopolysaccharide (LPS). Sheep received intraamniotic (IA) injections of media (control) or live Ureaplasma either 7 or 70 days before delivery. Another group received IA LPS 2 days before delivery. To test for interactions, U parvum-exposed animals were challenged with IA LPS, and delivered 2 days later. All animals were delivered preterm at 125 ± 1 day of gestation. Both IA Ureaplasma and LPS induced leukocyte infiltration of chorioamnion. LPS greatly increased the expression of proinflammatory cytokines and myeloperoxidase in leukocytes, while Ureaplasma alone caused modest responses. Interestingly, 7-day but not 70-day Ureaplasma exposure significantly down-regulated LPS-induced proinflammatory cytokines and myeloperoxidase expression in the chorioamnion. Acute (7-day) U parvum exposure can suppress LPS-induced chorioamnionitis. Copyright © 2013 Mosby, Inc. All rights reserved.

  3. Equine colostral carbohydrates reduce lipopolysaccharide-induced inflammatory responses in equine peripheral blood mononuclear cells.

    Science.gov (United States)

    Vendrig, J C; Coffeng, L E; Fink-Gremmels, J

    2012-12-01

    Increasing evidence suggests that reactions to lipopolysaccharide (LPS), particularly in the gut, can be partly or completely mitigated by colostrum- and milk-derived oligosaccharides. Confirmation of this hypothesis could lead to the development of new therapeutic concepts. To demonstrate the influence of equine colostral carbohydrates on the inflammatory response in an in vitro model with equine peripheral blood mononuclear cells (PBMCs). Carbohydrates were extracted from mare colostrum, and then evaluated for their influence on LPS-induced inflammatory responses in PBMCs isolated from the same mares, mRNA expression of tumour necrosis factor-alpha, interleukin-6 and interleukin-10 was measured as well as the protein levels of tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10). Equine colostral carbohydrates significantly reduced LPS-induced TNF-alpha protein at both times measured and significantly reduced LPS-induced TNF-alpha, IL-6 and IL-10 mRNA expression by PBMCs. Moreover, cell viability significantly increased in the presence of high concentrations of colostral carbohydrates. Carbohydrates derived from equine colostrum reduce LPS-induced inflammatory responses of equine PBMCs. Colostrum and milk-derived carbohydrates are promising candidates for new concepts in preventive and regenerative medicine.

  4. Chondroitin Sulfate-Rich Extract of Skate Cartilage Attenuates Lipopolysaccharide-Induced Liver Damage in Mice.

    Science.gov (United States)

    Song, Yeong Ok; Kim, Mijeong; Woo, Minji; Baek, Jang-Mi; Kang, Keon-Hee; Kim, Sang-Ho; Roh, Seong-Soo; Park, Chan Hum; Jeong, Kap-Seop; Noh, Jeong-Sook

    2017-06-15

    The protective effects of a chondroitin sulfate-rich extract (CSE) from skate cartilage against lipopolysaccharide (LPS)-induced hepatic damage were investigated, and its mechanism of action was compared with that of chondroitin sulfate (CS) from shark cartilage. ICR mice were orally administrated 200 mg/kg body weight (BW) of CS or 400 mg/kg BW of CSE for 3 consecutive days, followed by a one-time intraperitoneal injection of LPS (20 mg/kg BW). The experimental groups were vehicle treatment without LPS injection (NC group), vehicle treatment with LPS injection (LPS group), CS pretreatment with LPS injection (CS group), and CSE pretreatment with LPS injection (CSE group). Hepatic antioxidant enzyme expression levels in the CS and CSE groups were increased relative to those in the LPS group. In LPS-insulted hepatic tissue, inflammatory factors were augmented relative to those in the NC group, but were significantly suppressed by pretreatment with CS or CSE. Moreover, CS and CSE alleviated the LPS-induced apoptotic factors and mitogen-activated protein kinase (MAPK). In addition, CS and CSE effectively decreased the serum lipid concentrations and downregulated hepatic sterol regulatory element-binding proteins expression. In conclusion, the skate CSE could protect against LPS-induced hepatic dyslipidemia, oxidative stress, inflammation, and apoptosis, probably through the regulation of MAPK signaling.

  5. [Inhibitory effect of kaempferol on inflammatory response of lipopolysaccharide-stimulated human mast cells].

    Science.gov (United States)

    Zhou, Yun-jiang; Wang, Hu; Li, Li; Sui, He-huan; Huang, Jia-jun

    2015-06-01

    This study is to investigate the inhibitory effect of kaempferol on inflammatory response of lipopolysaccharide(LPS)-stimulated HMC-1 mast cells. The cytotoxicity of kaempferol to HMC-1 mast cells were analyzed by using MTT assay and then the administration concentrations of kaempferol were established. Histamine, IL-6, IL-8, IL-1β and TNF-α were measured using ELISA assay in activated HMC-1 mast cells after incubation with various concentrations of kaempferol (10, 20 and 40 µmol.L-1). Western blot was used to test the protein expression of p-IKKβ, IκBα, p-IκBα and nucleus NF-κB of LPS-induced HMC-1 mast cells after incubation with different concentrations of kaempferol. The optimal concentrations of kaempferol were defined as the range from 5 µmol.L-1 to 40 µmol.L-1. Kaempferol significantly decreased the release of histamine, IL-6, IL-8, IL-1β and TNF-α of activated HMC-1 mast cells (Pkaempferol, the protein expression of p-IKKβ, p-IKBa and nucleus NF-κB (p65) markedly reduced in LPS-stimulated HMC-1 mast cells (Pkaempferol markedly inhibit mast cell-mediated inflammatory response. At the same time, kaempferol can inhibit the activation of IKKβ, block the phosphorylation of IκBα, prevent NF-KB entering into the nucleus, and then decrease the release of inflammatory mediators.

  6. Cytokine and surface receptor diversity of NK cells in resistant C3H/HeN and susceptible BALB/c mice with chronic Pseudomonas aeruginosa lung infection

    DEFF Research Database (Denmark)

    Calum, Henrik; Moser, Claus; Jensen, Peter Østrup

    2003-01-01

    The purpose of the present study was to investigate whether NK cells from resistant C3H/HeN mice and susceptible BALB/c mice showed different release of cytokines and expression of surface molecules during chronic P. aeruginosa lung infection using alginate-embedded P. aeruginosa mimicking...... expression of the LFA-1 and Fc receptors on NK cells. At day 2, IFN-gamma levels increased in C3H/HeN mice but decreased in BALB/c mice. The GM-CSF levels increased only in the C3H/HeN mice at day 1 and 2. Surface expression of LFA-1 on the NK cells was higher in C3H/HeN mice at day 1 and 2. In contrast...

  7. Stimulation of the Angiotensin II AT2 Receptor is Anti-inflammatory in Human Lipopolysaccharide-Activated Monocytic Cells

    DEFF Research Database (Denmark)

    Menk, Mario; Graw, Jan Adriaan; von Haefen, Clarissa

    2015-01-01

    and the translational level over course of time. Treatment with C21 attenuated the expression of TNFα, IL-6, and IL-10 after LPS challenge in both cell lines in a time- and dose-dependent manner. We conclude that selective AT2 receptor stimulation acts anti-inflammatory in human monocytes. Modulation of cytokine......Recently, AT2 receptors have been discovered on the surface of human immunocompetent cells such as monocytes. Data on regulative properties of this receptor on the cellular immune response are poor. We hypothesized that direct stimulation of the AT2 receptor mediates anti-inflammatory responses...... in these cells. Human monocytic THP-1 and U937 cells were stimulated with lipopolysaccharide (LPS) and the selective AT2 receptor agonist Compound 21 (C21). Expression of pro- and anti-inflammatory cytokines IL-6, IL-10, tumor necrosis factor-α (TNFα), and IL-1β were analyzed on both the transcriptional...

  8. Chromosomal mechanisms of aminoglycoside resistance in Pseudomonas aeruginosa isolates from cystic fibrosis patients

    DEFF Research Database (Denmark)

    Islam, S; Oh, H; Jalal, S

    2009-01-01

    pump protein MexY was determined by real-time PCR and correlated with susceptibilities to amikacin and tobramycin. The chromosomal genes mexZ, rplY, galU, PA5471 and nuoG, which were found to have a role in the gradual increase in MICs of aminoglycoside antibiotics in laboratory mutants of P....... aeruginosa, were analysed. MexY mRNA overproduction was found in 17/20 isolates collected in 1994 and 1997, and was correlated with decreased susceptibility to aminoglycosides. Alteration of the MexXY-OprM efflux system has been the main mechanism of resistance to aminoglycoside antibiotics in CF P......In total, 40 Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients were included in this study. Twenty of these were collected in 1994 and 1997, from six CF patients, and the rest were collected from different CF patients in 2000 and 2001. The relative expression of mRNA for the efflux...

  9. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

    2016-02-19

    Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections.

  10. Negative regulation of quorum-sensing systems in Pseudomonas aeruginosa by ATP-dependent Lon protease.

    Science.gov (United States)

    Takaya, Akiko; Tabuchi, Fumiaki; Tsuchiya, Hiroko; Isogai, Emiko; Yamamoto, Tomoko

    2008-06-01

    Lon protease, a member of the ATP-dependent protease family, regulates numerous cellular systems by degrading specific substrates. Here, we demonstrate that Lon is involved in the regulation of quorum-sensing (QS) signaling systems in Pseudomonas aeruginosa, an opportunistic human pathogen. The organism has two acyl-homoserine lactone (HSL)-mediated QS systems, LasR/LasI and RhlR/RhlI. Many reports have demonstrated that these two systems are regulated and interconnected by global regulators. We found that lon-disrupted cells overproduce pyocyanin, the biosynthesis of which depends on the RhlR/RhlI system, and show increased levels of a transcriptional regulator, RhlR. The QS systems are organized hierarchically: the RhlR/RhlI system is subordinate to LasR/LasI. To elucidate the mechanism by which Lon negatively regulates RhlR/RhlI, we examined the effect of lon disruption on the LasR/LasI system. We found that Lon represses the expression of LasR/LasI by degrading LasI, an HSL synthase, leading to negative regulation of the RhlR/RhlI system. RhlR/RhlI was also shown to be regulated by Lon independently of LasR/LasI via regulation of RhlI, an HSL synthase. In view of these findings, it is suggested that Lon protease is a powerful negative regulator of both HSL-mediated QS systems in P. aeruginosa.

  11. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S.; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

    2016-01-01

    Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a ‘last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections. PMID:26892159

  12. Selection of Functional Quorum Sensing Systems by Lysogenic Bacteriophages in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Miguel A. Saucedo-Mora

    2017-08-01

    Full Text Available Quorum sensing (QS in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS.

  13. Quorum-Quenching Human Designer Cells for Closed-Loop Control of Pseudomonas aeruginosa Biofilms.

    Science.gov (United States)

    Sedlmayer, Ferdinand; Jaeger, Tina; Jenal, Urs; Fussenegger, Martin

    2017-08-09

    Current antibiotics gradually lose their efficacy against chronic Pseudomonas aeruginosa infections due to development of increased resistance mediated by biofilm formation, as well as the large arsenal of microbial virulence factors that are coordinated by the cell density-dependent phenomenon of quorum sensing. Here, we address this issue by using synthetic biology principles to rationally engineer quorum-quencher cells with closed-loop control to autonomously dampen virulence and interfere with biofilm integrity. Pathogen-derived signals dynamically activate a synthetic mammalian autoinducer sensor driving downstream expression of next-generation anti-infectives. Engineered cells were able to sensitively score autoinducer levels from P. aeruginosa clinical isolates and mount a 2-fold defense consisting of an autoinducer-inactivating enzyme to silence bacterial quorum sensing and a bipartite antibiofilm effector to dissolve the biofilm matrix. The self-guided cellular device fully cleared autoinducers, potentiated bacterial antibiotic susceptibility, substantially reduced biofilms, and alleviated cytotoxicity to lung epithelial cells. We believe this strategy of dividing otherwise coordinated pathogens and breaking up their shielded stronghold represents a blueprint for cellular anti-infectives in the postantibiotic era.

  14. Pseudomonas aeruginosa adaptation to lungs of cystic fibrosis patients leads to lowered resistance to phage and protist enemies.

    Directory of Open Access Journals (Sweden)

    Ville-Petri Friman

    Full Text Available Pathogenic life styles can lead to highly specialized interactions with host species, potentially resulting in fitness trade-offs in other ecological contexts. Here we studied how adaptation of the environmentally transmitted bacterial pathogen, Pseudomonas aeruginosa, to cystic fibrosis (CF patients affects its survival in the presence of natural phage (14/1, ΦKZ, PNM and PT7 and protist (Tetrahymena thermophila and Acanthamoebae polyphaga enemies. We found that most of the bacteria isolated from relatively recently intermittently colonised patients (1-25 months, were innately phage-resistant and highly toxic for protists. In contrast, bacteria isolated from long time chronically infected patients (2-23 years, were less efficient in both resisting phages and killing protists. Moreover, chronic isolates showed reduced killing of wax moth larvae (Galleria mellonella probably due to weaker in vitro growth and protease expression. These results suggest that P. aeruginosa long-term adaptation to CF-lungs could trade off with its survival in aquatic environmental reservoirs in the presence of microbial enemies, while lowered virulence could reduce pathogen opportunities to infect insect vectors; factors that are both likely to result in poorer environmental transmission. From an applied perspective, phage therapy could be useful against chronic P. aeruginosa lung infections that are often characterized by multidrug resistance: chronic isolates were least resistant to phages and their poor growth will likely slow down the emergence of beneficial resistance mutations.

  15. N-acetylcysteine selectively antagonizes the activity of imipenem in Pseudomonas aeruginosa by an OprD-mediated mechanism.

    Science.gov (United States)

    Rodríguez-Beltrán, Jerónimo; Cabot, Gabriel; Valencia, Estela Ynés; Costas, Coloma; Bou, German; Oliver, Antonio; Blázquez, Jesús

    2015-01-01

    The modulating effect of N-acetylcysteine (NAC) on the activity of different antibiotics has been studied in Pseudomonas aeruginosa. Our results demonstrate that, in contrast to previous reports, only the activity of imipenem is clearly affected by NAC. MIC and checkerboard determinations indicate that the NAC-based modulation of imipenem activity is dependent mainly on OprD. SDS-PAGE of outer membrane proteins (OMPs) after NAC treatments demonstrates that NAC does not modify the expression of OprD, suggesting that NAC competitively inhibits the uptake of imipenem through OprD. Similar effects on imipenem activity were obtained with P. aeruginosa clinical isolates. Our results indicate that imipenem-susceptible P. aeruginosa strains become resistant upon simultaneous treatment with NAC and imipenem. Moreover, the generality of the observed effects of NAC on antibiotic activity was assessed with two additional bacterial species, Escherichia coli and Acinetobacter baumannii. Caution should be taken during treatments, as the activity of imipenem may be modified by physiologically attainable concentrations of NAC, particularly during intravenous and nebulized regimes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Contrasting silver nanoparticle toxicity and detoxification strategies in Microcystis aeruginosa and Chlorella vulgaris: New insights from proteomic and physiological analyses.

    Science.gov (United States)

    Qian, Haifeng; Zhu, Kun; Lu, Haiping; Lavoie, Michel; Chen, Si; Zhou, Zhongjing; Deng, Zhiping; Chen, Jun; Fu, Zhengwei

    2016-12-01

    Several studies have shown that AgNPs can be toxic to phytoplankton, but the underlying cellular mechanisms still remain largely unknown. Here we studied the toxicity and detoxification of AgNPs (and ionic silver released by the AgNPs) in a prokaryotic (Microcystis aeruginosa) and a eukaryotic (Chlorella vulgaris) freshwater phytoplankton species using a combination of proteomic, gene transcription, and physiological analyses. We show that AgNPs were more toxic to the growth, photosynthesis, antioxidant systems, and carbohydrate metabolism of M. aeruginosa than of C. vulgaris. C. vulgaris could detoxify efficiently AgNPs-induced ROS species via induction of antioxidant enzymes (superoxide dismutase or SOD, peroxidase or POD, catalase or CAT, and glutamine synthetase), allowing photosynthesis to continue unabated at growth-inhibitory AgNPs concentration. By contrast, the transcription and expression of SOD and POD in M. aeruginosa was inhibited by the same AgNPs exposure. The present study shed new lights on the AgNPs toxicity mechanisms and detoxification strategies in two freshwater algae of contrasting AgNPs sensitivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Dynamic Regulation of Delta-Opioid Receptor in Rat Trigeminal Ganglion Neurons by Lipopolysaccharide-induced Acute Pulpitis.

    Science.gov (United States)

    Huang, Jin; Lv, Yiheng; Fu, Yunjie; Ren, Lili; Wang, Pan; Liu, Baozhu; Huang, Keqiang; Bi, Jing

    2015-12-01

    Delta-opioid receptor (DOR) and its endogenous ligands distribute in trigeminal system and play a very important role in modulating peripheral inflammatory pain. DOR activation can trigger p44/42 mitogen-activated protein kinase (ERK1/2) and Akt signaling pathways, which participate in anti-inflammatory and neuroprotective effects. In this study, our purpose was to determine the dynamic changes of DOR in trigeminal ganglion (TG) neurons during the process of acute dental pulp inflammation and elucidate its possible mechanism. Forty rats were used to generate lipopolysaccharide-induced acute pulpitis animal models at 6, 12, and 24 hours and sham-operated groups. Acute pulpitis was confirmed by hematoxylin-eosin staining, and TG neuron activation was determined by anti-c-Fos immunohistochemistry. DOR protein and gene expression in TG was investigated by immunohistochemistry, Western blotting, and real-time polymerase chain reaction, and DOR expression in trigeminal nerves and dental pulp was also determined by immunohistochemistry. To further investigate the mechanism of DOR modulating acute inflammation, the change of pErk1/2 and pAkt in TG was examined by immunohistochemistry. Lipopolysaccharide could successfully induce acute pulpitis and activated TG neurons. Acute pulpitis could dynamically increase DOR protein and gene expression at 6, 12, and 24 hours in TG, and DOR dimerization was significantly increased at 12 and 24 hours. Acute pulpitis also induced the dynamic change of DOR protein in trigeminal nerve and dental pulp. Furthermore, ERK1/2 and Akt signaling pathways were inhibited in TG after acute pulpitis. Increased DOR expression and dimerization may play important roles in peripheral acute inflammatory pain. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. Annexin A5 binds to lipopolysaccharide and reduces its endotoxin activity.

    Science.gov (United States)

    Rand, Jacob H; Wu, Xiao-Xuan; Lin, Elaine Y; Griffel, Alexander; Gialanella, Philip; McKitrick, John C

    2012-01-01

    Annexin A5 (AnxA5) has a high affinity for phosphatidylserine. The protein is widely used to detect apoptotic cells because phosphatidylserine, a phospholipid that is normally present in the inner leaflets of cytoplasmic membranes, becomes translocated to the outer leaflets during programmed cell death. Here we report the novel observation that AnxA5 binds to Gram-negative bacteria via the lipid A domain of lipopolysaccharide (LPS). Binding of AnxA5 to bacteria was measured quantitatively, confirmed by fluorescence microscopy, and found to be inhibited by antibodies against lipid A. AnxA5 also bound to purified dot-blotted LPS and lipid A. Through ellipsometry, we found that the binding of AnxA5 to purified LPS was calcium dependent and rapid and showed a high affinity-characteristics similar to those of AnxA5 binding to phosphatidylserine. Initial functional studies indicated that AnxA5 can affect LPS activities. AnxA5 inhibited LPS-mediated gelation in the Limulus amebocyte lysate assay. Incubation of LPS with the protein reduced the quantity of tumor necrosis factor alpha (TNF-α) released by cultured monocytes compared to that released upon incubation with LPS alone. Initial in vivo experiments indicated that injection of mice with LPS preincubated with AnxA5 produced serum TNF-α levels lower than those seen after injection of LPS alone. These data demonstrate that AnxA5 binds to LPS and open paths to investigation of the potential biological and therapeutic implications of this interaction. AnxA5 is highly expressed in cells that have a barrier function-including, among others, vascular endothelium, placental trophoblasts, and epithelial cells lining bile ducts, renal tubules, mammary ducts, and nasal epithelium. The protein has been well characterized for its binding to phospholipid bilayers that contain phosphatidylserine. This report of a previously unrecognized activity of AnxA5 opens the door to investigation of the possibility that this binding may have

  19. Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

    Czech Academy of Sciences Publication Activity Database

    Sokolová, L.; Williamson, H.; Sýkora, Jan; Hof, Martin; Gray, H. B.; Brutschy, B.; Vlček, Antonín

    2011-01-01

    Roč. 115, č. 16 (2011), s. 4790-4800 ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * oligomers * pseudomonas aeruginosa azurin solutions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.696, year: 2011

  20. Pseudomonas aeruginosa Infections in a Tertiary Hospital in Nigeria ...

    African Journals Online (AJOL)

    Background: Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections. It exhibits innate resistance to a wide range of antibiotics thus causing high rates of morbidity and mortality worldwide. Objective: This study was done to determine the distribution and the antibiotic susceptibility ...

  1. Dechlorination of 1,2– dichloroethane by Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    As part of our attempt at isolating and stocking some indigenous microbial species, we isolated a bacterium from a waste dumpsite with appreciable dechlorination activity. 16S rDNA profiling revealed the isolate to be a strain of Pseudomonas aeruginosa and the sequence has been deposited in the NCBI nucleotide ...

  2. Heavy Metal uptake Potentials of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Uptake of heavy metals, silver and cadmium by Pseudomonas aeruginosa (a Gram negative bacterium) and Micrococcus luteus (a Gram positive bacterium) was investigated in Cadmium and Silver stock solution using ion selective electrodes. Silver and cadmium uptake by the two organisms was described by Langmuir ...

  3. Interleukin-18 impairs the pulmonary host response to Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Schultz, Marc J.; Knapp, Sylvia; Florquin, Sandrine; Pater, Jennie; Takeda, Kiyoshi; Akira, Shizuo; van der Poll, Tom

    2003-01-01

    Interleukin-18 (IL-18) is a potent cytokine with many different proinflammatory activities. To study the role of IL-18 in the pathogenesis of Pseudomonas pneumonia, IL-18-deficient (IL-18(-/-)) and wild-type mice were intranasally inoculated with Pseudomonas aeruginosa. IL-18 deficiency was

  4. Pseudomonas aeruginosa bacteraemia in an academic hospital in ...

    African Journals Online (AJOL)

    This study aimed at determining the clinical manifestations, outcome and prognostic factors associated with P. aeruginosa bacteraemia at the Chris Hani Baragwanath Hospital during the period 1998-99; to describe and quantify resistance to anti-pseudomonal drugs, and characterization of bacteraemic isolates, investigate ...

  5. Detection of Pseudomonas aeruginosa in sputum samples by ...

    African Journals Online (AJOL)

    samples obtained from CF patients may impede detection of microorganisms by FISH. The aim of this study was to test the application of biotin during FISH technique to reduce unspecific background fluorescence in sputum samples to facilitate and improve detection of P. aeruginosa. Sixty-three sputum samples from CF ...

  6. Potential use of Algae Microcystis aeruginosa (Chroococaceae) in ...

    African Journals Online (AJOL)

    A comparison of growth response of algal species in varying concentrations of petroleum products to assess their bioremediation potentials was carried out using Microcystis aeruginosa as test organism. The modified Chu #10 standard medium for algal culture was used for the experimental set up which lasted for ...

  7. Ciprofloxacin interactions with imipenem and amikacin against multiresistant Pseudomonas aeruginosa.

    OpenAIRE

    Giamarellou, H; Petrikkos, G

    1987-01-01

    In vitro interactions of ciprofloxacin with imipenem and amikacin were evaluated by the killing-curve technique against 26 Pseudomonas aeruginosa strains resistant to amikacin and resistant or moderately susceptible to ciprofloxacin and imipenem. Imipenem enhanced killing by ciprofloxacin in tests with 11 strains, whereas amikacin enhanced killing in tests with only 4 strains.

  8. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    Science.gov (United States)

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  9. Decrease of Pseudomonas aeruginosa biofilm formation by food waste materials

    Czech Academy of Sciences Publication Activity Database

    Maděrová, Z.; Horská, K.; Kim, S.-R.; Lee, Ch.-H.; Pospíšková, K.; Šafaříková, Miroslava; Šafařík, Ivo

    2016-01-01

    Roč. 73, č. 9 (2016), s. 2143-2149 ISSN 0273-1223 Institutional support: RVO:60077344 Keywords : biofilm * food waste materials * magnetic spent grain * Pseudomonas aeruginosa Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.197, year: 2016

  10. Characterization of Pseudomonas aeruginosa Chitinase, a Gradually Secreted Protein

    NARCIS (Netherlands)

    Folders, J. (Jindra); Algra, J. (Jon); Roelofs, M.S. (Marc); Loon, L.C. van; Tommassen, J.P.M.; Bitter, Wilbert

    2001-01-01

    The gram-negative bacterium Pseudomonas aeruginosa secretes many proteins into its extracellular environment via the type I, II, and III secretion systems. In this study, a gene, chiC, coding for an extracellular chitinolytic enzyme, was identified. The chiC gene encodes a polypeptide of 483 amino

  11. Control of Microcystis aeruginosa TH01109 with batangas mandarin ...

    African Journals Online (AJOL)

    We studied the inhibitory effects of batangas mandarin skin and dwarf banana peel on Microcystis aeruginosa. In laboratory assays, algal growth was significantly inhibited by the addition of mandarin skin extract (0.1% w/v). When the concentration of mandarin skin increased to 0.5% (w/v), no algal growth was detected, ...

  12. Typing of Pseudomonas aeruginosa strains in Norwegian cystic fibrosis patients

    DEFF Research Database (Denmark)

    Fluge, G; Ojeniyi, B; Høiby, N

    2001-01-01

    OBJECTIVES: Typing of Pseudomonas aeruginosa isolates from Norwegian cystic fibrosis (CF) patients with chronic Pseudomonas lung infection in order to see whether cross-infection might have occurred. METHODS: Isolates from 60 patients were collected during the years 1994-98, and typed by pulsed...

  13. Pyoverdine, the Major Siderophore in Pseudomonas aeruginosa, Evades NGAL Recognition

    Directory of Open Access Journals (Sweden)

    Mary E. Peek

    2012-01-01

    Full Text Available Pseudomonas aeruginosa is the most common pathogen that persists in the cystic fibrosis lungs. Bacteria such as P. aeruginosa secrete siderophores (iron-chelating molecules and the host limits bacterial growth by producing neutrophil-gelatinase-associated lipocalin (NGAL that specifically scavenges bacterial siderophores, therefore preventing bacteria from establishing infection. P. aeruginosa produces a major siderophore known as pyoverdine, found to be important for bacterial virulence and biofilm development. We report that pyoverdine did not bind to NGAL, as measured by tryptophan fluorescence quenching, while enterobactin bound to NGAL effectively causing a strong response. The experimental data indicate that pyoverdine evades NGAL recognition. We then employed a molecular modeling approach to simulate the binding of pyoverdine to human NGAL using NGAL’s published crystal structures. The docking of pyoverdine to NGAL predicted nine different docking positions; however, neither apo- nor ferric forms of pyoverdine docked into the ligand-binding site in the calyx of NGAL where siderophores are known to bind. The molecular modeling results offer structural support that pyoverdine does not bind to NGAL, confirming the results obtained in the tryptophan quenching assay. The data suggest that pyoverdine is a stealth siderophore that evades NGAL recognition allowing P. aeruginosa to establish chronic infections in CF lungs.

  14. Electrochemical reduction of oxygen catalyzed by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Cournet, Amandine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France)] [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Berge, Mathieu; Roques, Christine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France); Bergel, Alain [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Delia, Marie-Line, E-mail: marieline.delia@ensiacet.f [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France)

    2010-07-01

    Pseudomonas aeruginosa has already been shown to catalyze oxidation processes in the anode compartment of a microbial fuel cell. The present study focuses on the reverse capacity of the bacterium, i.e. reduction catalysis. Here we show that P. aeruginosa is able to catalyze the electrochemical reduction of oxygen. The use of cyclic voltammetry showed that, for a given range of potential values, the current generated in the presence of bacteria could reach up to four times the current obtained without bacteria. The adhesion of bacteria to the working electrode was necessary for the catalysis to be observed but was not sufficient. The electron transfer between the working electrode and the bacteria did not involve mediator metabolites like phenazines. The transfer was by direct contact. The catalysis required a certain contact duration between electrodes and live bacteria but after this delay, the metabolic activity of cells was no longer necessary. Membrane-bound proteins, like catalase, may be involved. Various strains of P. aeruginosa, including clinical isolates, were tested and all of them, even catalase-defective mutants, presented the same catalytic property. P. aeruginosa offers a new model for the analysis of reduction catalysis and the protocol designed here may provide a basis for developing an interesting tool in the field of bacterial adhesion.

  15. Induction of beta-lactamase production in Pseudomonas aeruginosa biofilm

    DEFF Research Database (Denmark)

    Giwercman, B; Jensen, E T; Høiby, N

    1991-01-01

    Imipenem induced high levels of beta-lactamase production in Pseudomonas aeruginosa biofilms. Piperacillin also induced beta-lactamase production in these biofilms but to a lesser degree. The combination of beta-lactamase production with other protective properties of the biofilm mode of growth c...... could be a major reason for the persistence of this sessile bacterium in chronic infections....

  16. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and Pseudomonas fluorescence) on phenol chemostat culture was carried out. The data were checked for consistency using carbon and available electron balances. When more than the minimum number of variables are measured, ...

  17. Interactions between the antimicrobial agent triclosan and the bloom-forming cyanobacteria Microcystis aeruginosa

    International Nuclear Information System (INIS)

    Huang, Xiaolong; Tu, Yenan; Song, Chaofeng; Li, Tiancui; Lin, Juan; Wu, Yonghong; Liu, Jiantong; Wu, Chenxi

    2016-01-01

    Highlights: • Triclosan inhibit the growth and photosynthesis of M. aeruginosa at environmental relevant level. • TEM imaging showed destruction of M. aeruginosa cell ultrastructure during triclosan exposure. • Triclosan can be biotransformed by M. aeruginosa with methylation as a major pathway. • Presence of M. aeruginosa enhanced the photodegradation of triclosan. - Abstract: Cyanobacteria can co-exist in eutrophic waters with chemicals or other substances derived from personal care products discharged in wastewater. In this work, we investigate the interactions between the antimicrobial agent triclosan (TCS) and the bloom-forming cyanobacteria Microcystis aeruginosa. M. aeruginosa was very sensitive to TCS with the 96 h lowest observed effect concentration of 1.0 and 10 μg/L for inhibition of growth and photosynthetic activity, respectively. Exposure to TCS at environmentally relevant levels (0.1–2.0 μg/L) also affected the activities of superoxide dismutase (SOD) and the generation of reduced glutathione (GSH), while microcystin production was not affected. Transmission electron microscope (TEM) examination showed the destruction of M. aeruginosa cell ultrastructure during TCS exposure. TCS however, can be biotransformed by M. aeruginosa with methylation as a major biotransformation pathway. Furthermore, the presence of M. aeruginosa in solution promoted the photodegradation of TCS. Overall, our results demonstrate that M. aeruginosa plays an important role in the dissipation of TCS in aquatic environments but high residual TCS can exert toxic effects on M. aeruginosa.

  18. Interactions between the antimicrobial agent triclosan and the bloom-forming cyanobacteria Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaolong [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Wuhan Zhongke Hydrobiological Environment Engineering Co., Ltd, Wuhan 430071 (China); Tu, Yenan; Song, Chaofeng; Li, Tiancui; Lin, Juan [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Wu, Yonghong [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, Nanjing 210008 (China); Liu, Jiantong [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Wu, Chenxi, E-mail: chenxi.wu@ihb.ac.cn [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China)

    2016-03-15

    Highlights: • Triclosan inhibit the growth and photosynthesis of M. aeruginosa at environmental relevant level. • TEM imaging showed destruction of M. aeruginosa cell ultrastructure during triclosan exposure. • Triclosan can be biotransformed by M. aeruginosa with methylation as a major pathway. • Presence of M. aeruginosa enhanced the photodegradation of triclosan. - Abstract: Cyanobacteria can co-exist in eutrophic waters with chemicals or other substances derived from personal care products discharged in wastewater. In this work, we investigate the interactions between the antimicrobial agent triclosan (TCS) and the bloom-forming cyanobacteria Microcystis aeruginosa. M. aeruginosa was very sensitive to TCS with the 96 h lowest observed effect concentration of 1.0 and 10 μg/L for inhibition of growth and photosynthetic activity, respectively. Exposure to TCS at environmentally relevant levels (0.1–2.0 μg/L) also affected the activities of superoxide dismutase (SOD) and the generation of reduced glutathione (GSH), while microcystin production was not affected. Transmission electron microscope (TEM) examination showed the destruction of M. aeruginosa cell ultrastructure during TCS exposure. TCS however, can be biotransformed by M. aeruginosa with methylation as a major biotransformation pathway. Furthermore, the presence of M. aeruginosa in solution promoted the photodegradation of TCS. Overall, our results demonstrate that M. aeruginosa plays an important role in the dissipation of TCS in aquatic environments but high residual TCS can exert toxic effects on M. aeruginosa.

  19. Inhibition of Pseudomonas aeruginosa virulence: characterization of the AprA-AprI interface and species selectivity.

    Science.gov (United States)

    Bardoel, Bart W; van Kessel, Kok P M; van Strijp, Jos A G; Milder, Fin J

    2012-01-20

    Pseudomonas aeruginosa secretes the virulence factor alkaline protease (AprA) to enhance its survival. AprA cleaves one of the key microbial recognition molecules, monomeric flagellin, and thereby diminishes Toll-like receptor 5 activation. In addition, AprA degrades host proteins such as complement proteins and cytokines. P. aeruginosa encodes a highly potent inhibitor of alkaline protease (AprI) that is solely located in the periplasm where it is presumed to protect periplasmic proteins against secreted AprA. We set out to study the enzyme-inhibitor interactions in more detail in order to provide a basis for future drug development. Structural and mutational studies reveal that the conserved N-terminal residues of AprI occupy the protease active site and are essential for inhibitory activity. We constructed peptides mimicking the N-terminus of AprI; however, these were incapable of inhibiting AprA-mediated flagellin cleavage. Furthermore, we expressed and purified AprI of P. aeruginosa and the homologous (37% sequence identity) AprI of Pseudomonas syringae, which remarkably show species specificity for their cognate protease. Exchange of the first five N-terminal residues between AprI of P. syringae and P. aeruginosa did not affect the observed specificity, whereas exchange of only six residues located at the AprI surface that contacts the protease did abolish specificity. These findings are elementary steps toward the design of molecules derived from the natural inhibitor of the virulence factor AprA and their use in therapeutic applications in Pseudomonas and other Gram-negative infections. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Revisiting the systemic lipopolysaccharide mediated neuroinflammation: Appraising the effect of l-cysteine mediated hydrogen sulphide on it

    Directory of Open Access Journals (Sweden)

    Abdulaziz S. Al-Saeedan

    2018-05-01

    Full Text Available The present research was ventured to examine the effect of l-cysteine on neuro-inflammation persuaded by peripheral lipopolysaccharides (LPS, 125 μg/kg, i.p. administration. No behavioral, biochemical, and inflammatory abnormality was perceived in the brain tissues of experimental animals after LPS administration. l-cysteine precipitated marginal symptoms of toxicity in the brain tissue. Similar pattern of wholesome effect of LPS were perceived when evaluated through the brain tissue fatty acid profile, histopathologically and NF-ĸBP65 protein expression. LPS was unsuccessful to alter the levels of hydrogen sulphide (H2S, cyclooxygenase (COX and lipoxygenase (LOX enzyme in brain tissue. LPS afforded significant peripheral toxicity, when figured out through inflammatory markers (COX, LOX, gaseous signaling molecules nitric oxide (NO, H2S, liver toxicity (SGOT, SGPT, and inflammatory transcription factor (NF-ĸBP65 and l-cysteine also provided a momentous protection against the same as well. The study inculcated two major finding, firstly LPS (i.p. cannot impart inflammatory changes to brain and secondly, l-cysteine can afford peripheral protection against deleterious effect of LPS (i.p. Keywords: Hydrogen sulphide, l-cysteine, Inflammation, Lipopolysaccharide, Neuroinflammation

  1. Secretory IgA as a diagnostic tool for Pseudomonas aeruginosa respiratory colonization

    DEFF Research Database (Denmark)

    Aanaes, Kasper; Johansen, Helle Krogh; Poulsen, Steen Seier

    2012-01-01

    BACKGROUND: Pseudomonas aeruginosa sinusitis may be the focus for intermittent lung colonization in patients with cystic fibrosis (CF). The sinusitis may induce elevated IgA levels in nasal secretion and saliva against P. aeruginosa. METHODS: 120 CF patients chronically infected, intermittently...... colonized or without P. aeruginosa in the lungs participated in this cross-sectional study. IgA and IgG against P. aeruginosa sonicate and alginate were measured in nasal secretions, saliva, and in serum by ELISA. RESULTS: The intermittently colonized patients had significantly higher IgA levels in nasal...... secretions and saliva than those without P. aeruginosa in the lungs, indicating that P. aeruginosa sinusitis may precede intermittent colonization and chronic infection of the lungs. CONCLUSIONS: Specific IgA against P. aeruginosa in nasal secretions and saliva can contribute to differentiation between...

  2. Colistin-Tobramycin Combinations Are Superior to Monotherapy Concerning the Killing of Biofilm Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Herrmann, G.; Yang, Liang; Wu, H.

    2010-01-01

    Background. Antibiotic combination therapy might be more efficient than single antibiotics to combat Pseudomonas aeruginosa biofilms in the airways of patients with cystic fibrosis. We tested the ability of colistin sulphatetobramycin combinations and single antibiotics to kill P. aeruginosa...... biofilms. Methods. P. aeruginosa biofilms were generated in vitro and in rat lungs. In a pilot study, 5 patients with cystic fibrosis inhaled colistin and then tobramycin for 4 weeks. The changes in P. aeruginosa counts and lung function were assessed before and after therapy. Results. Antibiotic...... combination therapy significantly reduced the number of P. aeruginosa cells in P. aeruginosa biofilm models in vitro. When rats were challenged with 1 x 10(7) cfu of P. aeruginosa, which was embedded in alginate beads, mortality rates, lung pathologic findings, and bacterial colony-forming unit counts were...

  3. [The effect of biyuanshu oral liquid on the formation of Pseudomonas aeruginosa biofilms in vitro].

    Science.gov (United States)

    Liu, Xiang; Chen, Haihong; Wang, Shengqing

    2012-07-01

    To observe the effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro. Pseudomonas aeruginosa biofilm was established by plate culture and detected by Scanning electron microscopy and AgNO3 staining. After treated with different dosages of biyuanshu oral liquid and erythromycin, the pseudomonas aeruginosa biofilms were observed by AgNO3 staining and the number of viable bacteria were measured by serial dilution. The pseudomonas aeruginosa biofilms could be detected by SEM at the seventh culture day and it was consistent with the detection of AgNO3 staining. The biyuanshu oral liquid and erythromycin have the effect on inhibiting the formation of pseudomonas aeruginosa biofilms. But with the already formed pseudomonas aeruginosa biofilms the inhibition was not significant. The serial dilution method showed that the viable counts of bacteria of biyuanshu oral liquid and erythromycin treated groups were significantly lower than those untreated groups (P formation of pseudomonas aeruginosa biofilms in vitro.

  4. Lipopolysaccharide promotes lipid accumulation in human adventitial fibroblasts via TLR4-NF-κB pathway

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2012-10-01

    Full Text Available Abstract Background Atherosclerosis is a chronic degenerative disease of the arteries and is thought to be one of the most common causes of death globally. In recent years, the functions of adventitial fibroblasts in the development of atherosclerosis and tissue repair have gained increased interests. LPS can increase the morbidity and mortality of atherosclerosis-associated cardiovascular disease. Although LPS increases neointimal via TLR4 activation has been reported, how LPS augments atherogenesis through acting on adventitial fibroblasts is still unknown. Here we explored lipid deposition within adventitial fibroblasts mediated by lipopolysaccharide (LPS to imitate inflammatory conditions. Results In our study, LPS enhanced lipid deposition by the up-regulated expression of adipose differentiation-related protein (ADRP as the silencing of ADRP abrogated lipid deposition in LPS-activated adventitial fibroblasts. In addition, pre-treatment with anti-Toll-like receptor 4 (TLR4 antibody diminished the LPS-induced lipid deposition and ADRP expression. Moreover, LPS induced translocation of nuclear factor-κB (NF-κB, which could markedly up-regulate lipid deposition as pre-treatment with the NF-κB inhibitor, PDTC, significantly reduced lipid droplets. In addition, the lowering lipid accumulation was accompanied with the decreased ADRP expression. Furthermore, LPS-induced adventitial fibroblasts secreted more monocyte chemoattractant protein (MCP-1, compared with transforming growth factor-β1 (TGF-β1. Conclusions Taken together, these results suggest that LPS promotes lipid accumulation via the up-regulation of ADRP expression through TLR4 activated downstream of NF-κB in adventitial fibroblasts. Increased levels of MCP-1 released from LPS-activated adventitial fibroblasts and lipid accumulation may accelerate monocytes recruitment and lipid-laden macrophage foam cells formation. Here, our study provides a new explanation as to how bacterial

  5. Lipopolysaccharide promotes lipid accumulation in human adventitial fibroblasts via TLR4-NF-κB pathway.

    Science.gov (United States)

    Wang, Jun; Si, Yanfang; Wu, Chen; Sun, Lu; Ma, Yudong; Ge, Aili; Li, Baomin

    2012-10-17

    Atherosclerosis is a chronic degenerative disease of the arteries and is thought to be one of the most common causes of death globally. In recent years, the functions of adventitial fibroblasts in the development of atherosclerosis and tissue repair have gained increased interests. LPS can increase the morbidity and mortality of atherosclerosis-associated cardiovascular disease. Although LPS increases neointimal via TLR4 activation has been reported, how LPS augments atherogenesis through acting on adventitial fibroblasts is still unknown. Here we explored lipid deposition within adventitial fibroblasts mediated by lipopolysaccharide (LPS) to imitate inflammatory conditions. In our study, LPS enhanced lipid deposition by the up-regulated expression of adipose differentiation-related protein (ADRP) as the silencing of ADRP abrogated lipid deposition in LPS-activated adventitial fibroblasts. In addition, pre-treatment with anti-Toll-like receptor 4 (TLR4) antibody diminished the LPS-induced lipid deposition and ADRP expression. Moreover, LPS induced translocation of nuclear factor-κB (NF-κB), which could markedly up-regulate lipid deposition as pre-treatment with the NF-κB inhibitor, PDTC, significantly reduced lipid droplets. In addition, the lowering lipid accumulation was accompanied with the decreased ADRP expression. Furthermore, LPS-induced adventitial fibroblasts secreted more monocyte chemoattractant protein (MCP-1), compared with transforming growth factor-β1 (TGF-β1). Taken together, these results suggest that LPS promotes lipid accumulation via the up-regulation of ADRP expression through TLR4 activated downstream of NF-κB in adventitial fibroblasts. Increased levels of MCP-1 released from LPS-activated adventitial fibroblasts and lipid accumulation may accelerate monocytes recruitment and lipid-laden macrophage foam cells formation. Here, our study provides a new explanation as to how bacterial infection contributes to the pathological process of

  6. Effects of Porphyromonas gingivalis LipopolysaccharideTolerized Monocytes on Inflammatory Responses in Neutrophils.

    Directory of Open Access Journals (Sweden)

    Xiang-Qing Zhu

    Full Text Available Periodontitis is a chronic inflammatory disease induced by bacteria. Exposure of the host to periodontal pathogens and their virulence factors induces a state of hyporesponsiveness to subsequent stimulations, which is termed endotoxin tolerance. The role and mechanism of lipopolysaccharide (LPS-tolerized monocytes in inflammatory responses in neutrophils are currently unclear. Here, conditioned supernatants were collected from THP-1 cells treated with or without repeated 1 μg/ml Porphyromonas gingivalis (P.gingivalis LPS. The chemotactic response of freshly isolated neutrophils recruited by supernatants was determined by a transwell migration assay, which demonstrated a reduced migration of neutrophils stimulated with supernatants from tolerized THP-1 cells in comparison to non-tolerized THP-1 cells. In addition, there was a marked increase in reactive oxygen species (ROS generation and a significant decrease in Caspase 3 activities in neutrophils treated with supernatants from THP-1 cells that were treated repeatedly with P.gingivalis LPS in comparison to single treatment. A cytokine antibody array was then used to assess cytokine expression patterns in THP-1 cells. In tolerized THP-1 cells, 43 cytokine (43/170 expression levels were decreased, including chemokine ligand 23 (CCL23 and IFN-γ, while 11 cytokine (11/170 expression levels were increased, such as death receptor 6 (DR6. Furthermore, there was decreased production of IFN-γ and epithelial neutrophil activating peptide-78 (ENA-78 in THP-1 cells af