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Sample records for biofilm og quorum

  1. Fremmedlegemeinfektioner--nyt om biofilm og quorum sensing

    DEFF Research Database (Denmark)

    Høiby, Niels; Johansen, Helle Krogh; Ciofu, Oana

    2007-01-01

    Biofilms are structured consortia of bacteria embedded in self-produced polymer matrix. Biofilms are resistant to antibiotics, disinfectives and phagocytosis. The persistence of foreign body infections is due to biofilms. Chronic P. aeruginosa lung infection in cystic fibrosis patients is a biofilm....... Bacteria in biofilms communicate by means of quorum sensing which activates genes for virulence factors. Biofilms can be prevented by antibiotic prophylaxis or early therapy or by quorum sensing inhibitors which make them susceptible to antibiotics and phagocytosis....

  2. Fremmedlegemeinfektioner--nyt om biofilm og quorum sensing

    DEFF Research Database (Denmark)

    Høiby, Niels; Johansen, Helle Krogh; Ciofu, Oana

    2007-01-01

    Biofilms are structured consortia of bacteria embedded in self-produced polymer matrix. Biofilms are resistant to antibiotics, disinfectives and phagocytosis. The persistence of foreign body infections is due to biofilms. Chronic P. aeruginosa lung infection in cystic fibrosis patients is a biofilm....... Bacteria in biofilms communicate by means of quorum sensing which activates genes for virulence factors. Biofilms can be prevented by antibiotic prophylaxis or early therapy or by quorum sensing inhibitors which make them susceptible to antibiotics and phagocytosis. Udgivelsesdato: 2007-Nov-26...

  3. 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...

  4. Quorum sensing inhibitors disable bacterial biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Givskov, Michael

    2011-01-01

    It is now evident that bacteria assume the biofilm mode of growth during chronic infections. The important hallmarks of biofilm infections are development of local inflammations, extreme tolerance to the action of conventional antimicrobial agents and an almost infinite capacity to evade the host...... defence systems in particular innate immunity. In the biofilm mode, bacteria use cell to cell communication termed quorum-sensing (QS) to coordinate expression of virulence, tolerance towards a number of antimicrobial agents and shielding against the host defence system. Chemical biology approaches may...

  5. Bacterial biofilms and quorum sensing: fidelity in bioremediation technology.

    Science.gov (United States)

    Mangwani, Neelam; Kumari, Supriya; Das, Surajit

    Increased contamination of the environment with toxic pollutants has paved the way for efficient strategies which can be implemented for environmental restoration. The major problem with conventional methods used for cleaning of pollutants is inefficiency and high economic costs. Bioremediation is a growing technology having advanced potential of cleaning pollutants. Biofilm formed by various micro-organisms potentially provide a suitable microenvironment for efficient bioremediation processes. High cell density and stress resistance properties of the biofilm environment provide opportunities for efficient metabolism of number of hydrophobic and toxic compounds. Bacterial biofilm formation is often regulated by quorum sensing (QS) which is a population density-based cell-cell communication process via signaling molecules. Numerous signaling molecules such as acyl homoserine lactones, peptides, autoinducer-2, diffusion signaling factors, and α-hydroxyketones have been studied in bacteria. Genetic alteration of QS machinery can be useful to modulate vital characters valuable for environmental applications such as biofilm formation, biosurfactant production, exopolysaccharide synthesis, horizontal gene transfer, catabolic gene expression, motility, and chemotaxis. These qualities are imperative for bacteria during degradation or detoxification of any pollutant. QS signals can be used for the fabrication of engineered biofilms with enhanced degradation kinetics. This review discusses the connection between QS and biofilm formation by bacteria in relation to bioremediation technology.

  6. Quorum-sensing and cheating in bacterial biofilms

    Science.gov (United States)

    Popat, Roman; Crusz, Shanika A.; Messina, Marco; Williams, Paul; West, Stuart A.; Diggle, Stephen P.

    2012-01-01

    The idea from human societies that self-interest can lead to a breakdown of cooperation at the group level is sometimes termed the public goods dilemma. We tested this idea in the opportunistic bacterial pathogen, Pseudomonas aeruginosa, by examining the influence of putative cheats that do not cooperate via cell-to-cell signalling (quorum-sensing, QS). We found that: (i) QS cheating occurs in biofilm populations owing to exploitation of QS-regulated public goods; (ii) the thickness and density of biofilms was reduced by the presence of non-cooperative cheats; (iii) population growth was reduced by the presence of cheats, and this reduction was greater in biofilms than in planktonic populations; (iv) the susceptibility of biofilms to antibiotics was increased by the presence of cheats; and (v) coercing cooperator cells to increase their level of cooperation decreases the extent to which the presence of cheats reduces population productivity. Our results provide clear support that conflict over public goods reduces population fitness in bacterial biofilms, and that this effect is greater than in planktonic populations. Finally, we discuss the clinical implications that arise from altering the susceptibility to antibiotics. PMID:23034707

  7. Use of Whole-Cell Bioassays for Screening Quorum Signaling, Quorum Interference, and Biofilm Dispersion.

    Science.gov (United States)

    Thornhill, Starla G; McLean, Robert J C

    2018-01-01

    In most bacteria, a global level of regulation, termed quorum sensing (QS), exists involving intercellular communication via the production and response to cell density-dependent signal molecules. QS has been associated with a number of important features in bacteria including virulence regulation and biofilm formation. Consequently, there is considerable interest in understanding, detecting, and inhibiting QS. N-acylated homoserine lactones (AHLs) are used as extracellular QS signals by a variety of Gram-negative bacteria. Chromobacterium violaceum, commonly found in soil and water, produces the characteristic purple pigment violacein, regulated by AHL-mediated QS. Based on this readily observed pigmentation phenotype, C. violaceum strains can be used to detect various aspects of AHL-mediated QS activity. In another commonly used bioassay organism, Agrobacterium tumefaciens, QS can be detected by the use of a reporter gene such as lacZ. Here, we describe several commonly used approaches incorporating C. violaceum and A. tumefaciens that can be used to detect AHL and QS inhibitors. Due to the inherent low susceptibility of biofilm bacteria to antimicrobial agents, biofilm dispersion, whereby bacteria reenter the planktonic community, is another increasingly important area of research. At least one signal, distinct from traditional QS, has been identified and there are a variety of other environmental factors that also trigger dispersion. We describe a microtiter-based experimental strategy whereby potential biofilm dispersion compounds can be screened.

  8. Quorum sensing in Acinetobacter: with special emphasis on antibiotic resistance, biofilm formation and quorum quenching

    Directory of Open Access Journals (Sweden)

    Bindu Subhadra

    2016-02-01

    Full Text Available Acinetobacter is an important nosocomial, opportunistic human pathogen that is gradually gaining more attention as a major health threat worldwide. Quorum sensing (QS is a cell-cell communication system in which specific signaling molecules called autoinducers accumulate in the medium as the population density grows and control various physiological processes including production of virulence factors, biofilm and development of antibiotic resistance. The complex QS machinery in Acinetobacter is mediated by a two-component system which is homologous to the typical LuxI/LuxR system found in Gram-negative bacteria. This cell signaling system comprises of a sensor protein that functions as autoinducer synthase and a receptor protein which binds to the signal molecules, acyl homoserine lactones inducing a cascade of reactions. Lately, disruption of QS has emerged as an anti-virulence strategy with great therapeutic potential. Here, we depict the current understanding of the existing QS network in Acinetobacter and describe important anti-virulent strategies developed in order to effectively tackle this pathogen. In addition, the prospects of quorum quenching to control Acinetobacter infections is also been discussed.

  9. Quorum sensing-controlled biofilm development in Serratia liquefaciens MG1

    DEFF Research Database (Denmark)

    Labbate, M.; Queek, S.Y.; Koh, K.S.

    2004-01-01

    aggregates and differentiated cell chains. Signal-based complementation of this mutant resulted in a biofilm with the wild-type architecture. Two quorum-sensing-regulated genes (bsmA and bsmB) involved in biofilm development were identified, and we propose that these genes are engaged in fine...

  10. Effect of Candida albicans and Candida dubliniensis planktonic/biofilm quorum sensing molecules on yeast morphogenesis

    OpenAIRE

    Henriques, Mariana; Martins, Margarida Isabel Barros Coelho; Azeredo, Joana; Oliveira, Rosário

    2006-01-01

    One of the aims of this work was to study the effect of farnesol, a quorum sensing molecule for Candida albicans, on morphologic inhibition of Candida dubliniensis. The second goal of this work was to confirm if Candida dubliniensis also excreted quorum sensing molecules, on both planktonic and biofilm forms. The results clearly demonstrate that Candida dubliniensis undergoes morphological alterations triggered by farnesol. It was also found that supernatants of Candida dubliniensis and Ca...

  11. Going beyond the Control of Quorum-Sensing to Combat Biofilm Infections

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    Wolf-Rainer Abraham

    2016-01-01

    Full Text Available Most bacteria attach to surfaces where they form a biofilm, cells embedded in a complex matrix of polymers. Cells in biofilms are much better protected against noxious agents than free-living cells. As a consequence it is very difficult to control pathogens with antibiotics in biofilm infections and novel targets are urgently needed. One approach aims at the communication between cells to form and to maintain a biofilm, a process called quorum-sensing. Water soluble small-sized molecules mediate this process and a number of antagonists of these compounds have been found. In this review natural compounds and synthetic drugs which do not interfere with the classical quorum-sensing compounds are discussed. For some of these compounds the targets are still not known, but others interfere with the formation of exopolysaccharides, virulence factors, or cell wall synthesis or they start an internal program of biofilm dispersal. Some of their targets are more conserved among pathogens than the receptors for quorum sensing autoinducers mediating quorum-sensing, enabling a broader application of the drug. The broad spectrum of mechanisms, the diversity of bioactive compounds, their activity against several targets, and the conservation of some targets among bacterial pathogens are promising aspects for several clinical applications of this type of biofilm-controlling compound in the future.

  12. 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...

  13. Biofilm ved kronisk rhinosinuitis og cystisk fibrose

    DEFF Research Database (Denmark)

    Fisker, Jacob; Buchwald, Christian von; Johansen, Helle Krogh

    2011-01-01

    Microbial biofilms are known to cause persistent foreign-body infections and have recently been acknowledged as involved in more than 65% of all human infections. Microbial biofilms have been detected in chronic rhinosinusitis, and chronic rhinosinusitis is mandatory in patients with cystic...

  14. Quorum-sensing regulation of the biofilm matrix genes (pel) of Pseudomonas aeruginosa.

    Science.gov (United States)

    Sakuragi, Yumiko; Kolter, Roberto

    2007-07-01

    Quorum sensing (QS) has been previously shown to play an important role in the development of Pseudomonas aeruginosa biofilms (D. G. Davies et al., Science 280:295-298, 1998). Although QS regulation of swarming and DNA release has been shown to play important roles in biofilm development, regulation of genes directly involved in biosynthesis of biofilm matrix has not been described. Here, transcription of the pel operon, essential for the production of a glucose-rich matrix exopolysaccharide, is shown to be greatly reduced in lasI and rhlI mutants. Chemical complementation of the lasI mutant with 3-oxo-dodecanoyl homoserine lactone restores pel transcription to the wild-type level and biofilm formation ability. These findings thus connect QS signaling and transcription of genes responsible for biofilm matrix biosynthesis.

  15. 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.

  16. Development of molecularly imprinted polymers to block quorum sensing and inhibit bacterial biofilm formation.

    Science.gov (United States)

    Ma, Luyao; Feng, Shaolong; de la Fuente-Nunez, Cesar; Hancock, Robert E W; Lu, Xiaonan

    2018-05-16

    Bacterial biofilms are responsible for most clinical infections and show increased antimicrobial resistance. In this study, molecularly imprinted polymers (MIPs) were developed to specifically capture prototypical quorum sensing autoinducers [i.e., N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12AHL)], interrupt quorum sensing, and subsequently inhibit biofilm formation of Pseudomonas aeruginosa, an important human nosocomial pathogen. The synthesis of MIPs was optimized by considering the amount and type of the functional monomers itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA). IA-based MIPs showed high adsorption affinity towards 3-oxo-C12AHL with an imprinting factor of 1.68. Compared to IA-based MIPs, the adsorption capacity of HEMA-based MIPs was improved 5-fold. HEMA-based MIPs significantly reduced biofilm formation (by ~65%), while biofilm suppression by IA-based MIPs was neutralized due to increased bacterial attachment. The developed MIPs represent promising alternative biofilm intervention agents that can be applied to surfaces relevant to clinical settings and food processing equipment.

  17. Sustained release of a novel anti-quorum-sensing agent against oral fungal biofilms.

    Science.gov (United States)

    Feldman, Mark; Shenderovich, Julia; Al-Quntar, Abed Al Aziz; Friedman, Michael; Steinberg, Doron

    2015-04-01

    Thiazolidinedione-8 (S-8) has recently been identified as a potential anti-quorum-sensing/antibiofilm agent against bacteria and fungi. Based on these results, we investigated the possibility of incorporating S-8 in a sustained-release membrane (SRM) to increase its pharmaceutical potential against Candida albicans biofilm. We demonstrated that SRM containing S-8 inhibits fungal biofilm formation in a time-dependent manner for 72 h, due to prolonged release of S-8. Moreover, the SRM effectively delivered the agent in its active form to locations outside the membrane reservoir. In addition, eradication of mature biofilm by the SRM containing S-8 was also significant. Of note, S-8-containing SRM affected the characteristics of mature C. albicans biofilm, such as thickness, exopolysaccharide (EPS) production, and morphogenesis of fungal cells. The concept of using an antibiofilm agent with no antifungal activity incorporated into a sustained-release delivery system is new in medicine and dentistry. This concept of an SRM containing a quorum-sensing quencher with an antibiofilm effect could pave the way for combating oral fungal infectious diseases. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Passive control of quorum sensing: prevention of Pseudomonas aeruginosa biofilm formation by imprinted polymers.

    Science.gov (United States)

    Piletska, Elena V; Stavroulakis, Georgios; Larcombe, Lee D; Whitcombe, Michael J; Sharma, Anant; Primrose, Sandy; Robinson, Gary K; Piletsky, Sergey A

    2011-04-11

    Here we present the first molecular imprinted polymer (MIP) that is able to attenuate the biofilm formation of the opportunistic human pathogen Pseudomonas aeruginosa through specific sequestration of its signal molecule N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C(12)-AHL). The MIP was rationally designed using computational modeling, and its capacity and specificity and that of a corresponding blank polymer toward signal molecule of P. aeruginosa (3-oxo-C(12)-AHL) and its analogue were tested. The biofilm formation in the presence of polymers and without polymers was studied using scanning confocal laser microscopy. Staining with crystal violet dye was used for the quantification of the biofilm formation. A significant reduction of the biofilm growth was observed in the presence of MIP (>80%), which was superior to that of the resin prepared without template, which showed a reduction of 40% in comparison with biofilm, which was grown without polymer addition. It was shown that 3-oxo-C(12)-AHL-specific MIP prevented the development of quorum-sensing-controlled phenotypes (in this case, biofilm formation) from being up-regulated. The developed MIP could be considered as a new tool for the elimination of life-threatening infections in a multitude of practical applications; it could, for example, be grafted on the surface of medical devices such as catheters and lenses, be a component of paints, or be used as a wound adsorbent.

  19. Effects of ambroxol on biofilm adhesion and viability of Pseudomonas aeruginosa quorum sensing defective strain

    Directory of Open Access Journals (Sweden)

    Qi LU

    2013-07-01

    Full Text Available Objective To investigate the effects of ambroxol on the biofilm viability and pristine adhesion of Pseudomonas aeruginosa wild (PAO1 and quorum sensing defective strain (QS, gene deletion of ∆lasI and ∆rhlI. Methods The biofilm was treated by different concentrations (0, 1.875, 3.75mg/ml of ambroxol. The number of colony was measured with agar plate, multifunction fluorometer was used to measure the fluorescence intensity of PAO1 and QS strains at the bottom of 96-well plate. The adhesion ratio (% was calculated to determine the effects of ambroxol on bacterial biofilm adhesion. Results Ambroxol treatment reduced the survival rate of the mutant strains compared to that of wild strain, even though the QS strain had increased the adhesion in the presence of ambroxol compared to that of wild strain (P<0.05. Conclusion Ambroxol has a property of significantly antagonizing quorum-sensing system, suggesting that it might be of importance in treatment against chronic Pseudomonasaeruginosainfections.

  20. Characterization of type 2 quorum sensing in Klebsiella pneumoniae and relationship with biofilm formation

    DEFF Research Database (Denmark)

    Balestrino, D.; Haagensen, Janus Anders Juul; Rich, C.

    2005-01-01

    Quorum sensing is a process by which bacteria communicate by using secreted chemical signaling molecules called autoinducers. Many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density by this mechanism. In this study, ...... steps of biofilm formation. These data suggest that a LuxS-dependent signal plays a role in the early stages of biofilm formation by K. pneumoniae....... observed in minimal medium supplemented with glycerol. To determine the potential role of luxS in colonization processes, a K. pneumoniae luxS isogenic mutant was constructed and tested for its capacity to form biofilms in vitro on an abiotic surface and to colonize the intestinal tract in a murine model....... No difference was observed in the level of intestinal colonization between the wild-type strain and the luxS mutant. Microscopic analysis of biofilm structures revealed that the luxS mutant was able to form a mature biofilm but with reduced capacities in the development of microcolonies, mostly in the early...

  1. Inhibition of biofilm development of uropathogens by curcumin - an anti-quorum sensing agent from Curcuma longa.

    Science.gov (United States)

    Packiavathy, Issac Abraham Sybiya Vasantha; Priya, Selvam; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2014-04-01

    Urinary tract infection is caused primarily by the quorum sensing (QS)-dependent biofilm forming ability of uropathogens. In the present investigation, an anti-quorum sensing (anti-QS) agent curcumin from Curcuma longa (turmeric) was shown to inhibit the biofilm formation of uropathogens, such as Escherichia coli, Pseudomonas aeruginosa PAO1, Proteus mirabilis and Serratia marcescens, possibly by interfering with their QS systems. The antibiofilm potential of curcumin on uropathogens as well as its efficacy in disturbing the mature biofilms was examined under light microscope and confocal laser scanning microscope. The treatment with curcumin was also found to attenuate the QS-dependent factors, such as exopolysaccharide production, alginate production, swimming and swarming motility of uropathogens. Furthermore, it was documented that curcumin enhanced the susceptibility of a marker strain and uropathogens to conventional antibiotics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Inhibition of Steptococcus mutans biofilm formation by extracts of Tenacibaculum sp. 20J, a bacterium with wide-spectrum quorum quenching activity

    OpenAIRE

    Muras, Andrea; Mayer, Celia; Romero, Manuel; Camino, Tamara; Ferrer, Maria D.; Mira, Alex; Otero, Ana

    2018-01-01

    ABSTRACT Background: Previous studies have suggested the quorum sensing signal AI-2 as a potential target to prevent the biofilm formation by Streptococcus mutans, a pathogen involved in tooth decay. Objective: To obtain inhibition of biofilm formation by S. mutans by extracts obtained from the marine bacterium Tenacibaculum sp. 20J interfering with the AI-2 quorum sensing system. Design: The AI-2 inhibitory activity was tested with the biosensors Vibrio harveyi BB170 and JMH597. S. mutans AT...

  3. Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors.

    Directory of Open Access Journals (Sweden)

    Dana Ziuzina

    Full Text Available The main objectives of this work were to investigate the effect of atmospheric cold plasma (ACP against a range of microbial biofilms commonly implicated in foodborne and healthcare associated human infections and against P. aeruginosa quorum sensing (QS-regulated virulence factors, such as pyocyanin, elastase (Las B and biofilm formation capacity post-ACP treatment. The effect of processing factors, namely treatment time and mode of plasma exposure on antimicrobial activity of ACP were also examined. Antibiofilm activity was assessed for E. coli, L. monocytogenes and S. aureus in terms of reduction of culturability and retention of metabolic activity using colony count and XTT assays, respectively. All samples were treated 'inpack' using sealed polypropylene containers with a high voltage dielectric barrier discharge ACP generated at 80 kV for 0, 60, 120 and 300 s and a post treatment storage time of 24 h. According to colony counts, ACP treatment for 60 s reduced populations of E. coli to undetectable levels, whereas 300 s was necessary to significantly reduce populations of L. monocytogenes and S. aureus biofilms. The results obtained from XTT assay indicated possible induction of viable but non culturable state of bacteria. With respect to P. aeruginosa QS-related virulence factors, the production of pyocyanin was significantly inhibited after short treatment times, but reduction of elastase was notable only after 300 s and no reduction in actual biofilm formation was achieved post-ACP treatment. Importantly, reduction of virulence factors was associated with reduction of the cytotoxic effects of the bacterial supernatant on CHO-K1 cells, regardless of mode and duration of treatment. The results of this study point to ACP technology as an effective strategy for inactivation of established biofilms and may play an important role in attenuation of virulence of pathogenic bacteria. Further investigation is warranted to propose direct evidence

  4. The CpAL quorum sensing system regulates production of hemolysins CPA and PFO to build Clostridium perfringens biofilms.

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    Vidal, Jorge E; Shak, Joshua R; Canizalez-Roman, Adrian

    2015-06-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

    Science.gov (United States)

    Shak, Joshua R.; Canizalez-Roman, Adrian

    2015-01-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. PMID:25824838

  6. 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.

  7. In vitro antibiofilm efficacy of Piper betle against quorum sensing mediated biofilm formation of luminescent Vibrio harveyi.

    Science.gov (United States)

    Srinivasan, Ramanathan; Santhakumari, Sivasubramanian; Ravi, Arumugam Veera

    2017-09-01

    Vibrio harveyi is a potent biofilm former, which confers resistance to multiple antimicrobials, disinfectants, chemicals and biocides. The prevalence of biofilm mediated antibiotic resistance among aquatic bacterial pathogens stresses the search for novel alternative approach to treat vibriosis in aquaculture. Exploring suitable therapeutics from natural resources could be a novel area of research. Therefore, this work was executed to evaluate the inhibitory effect of Piper betle ethyl acetate extract (PBE) on bioluminescence production and biofilm formation of V. harveyi. Minimal inhibitory concentration (MIC) of PBE against planktonic V. harveyi was found to be 1600 μg ml -1 ; furthermore, PBE inhibited the quorum sensing (QS) mediated bioluminescence production and biofilm formation in V. harveyi upto 98 and 74% respectively, at its sub-MIC concentration of 400 μg ml -1 without affecting their cell viability. Similar results were obtained for exopolysaccharides production and swimming motility related to biofilm formation of V. harveyi, where PBE reduced EPS production upto 64%. Light and confocal laser scanning microscopic analyses further confirmed that the PBE effectively prevented the initial attachment as well as microcolonies formation of V. harveyi biofilm, when compared to their untreated controls. This study demonstrates the promising antibiofilm activity of PBE and confirms the ethnopharmacological potential of this plant against V. harveyi infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Influence of Nutrient Availability and Quorum Sensing on the Formation of Metabolically Inactive Microcolonies Within Structurally Heterogeneous Bacterial Biofilms: An Individual-Based 3D Cellular Automata Model.

    Science.gov (United States)

    Machineni, Lakshmi; Rajapantul, Anil; Nandamuri, Vandana; Pawar, Parag D

    2017-03-01

    The resistance of bacterial biofilms to antibiotic treatment has been attributed to the emergence of structurally heterogeneous microenvironments containing metabolically inactive cell populations. In this study, we use a three-dimensional individual-based cellular automata model to investigate the influence of nutrient availability and quorum sensing on microbial heterogeneity in growing biofilms. Mature biofilms exhibited at least three structurally distinct strata: a high-volume, homogeneous region sandwiched between two compact sections of high heterogeneity. Cell death occurred preferentially in layers in close proximity to the substratum, resulting in increased heterogeneity in this section of the biofilm; the thickness and heterogeneity of this lowermost layer increased with time, ultimately leading to sloughing. The model predicted the formation of metabolically dormant cellular microniches embedded within faster-growing cell clusters. Biofilms utilizing quorum sensing were more heterogeneous compared to their non-quorum sensing counterparts, and resisted sloughing, featuring a cell-devoid layer of EPS atop the substratum upon which the remainder of the biofilm developed. Overall, our study provides a computational framework to analyze metabolic diversity and heterogeneity of biofilm-associated microorganisms and may pave the way toward gaining further insights into the biophysical mechanisms of antibiotic resistance.

  9. Inhibition of Steptococcus mutans biofilm formation by extracts of Tenacibaculum sp. 20J, a bacterium with wide-spectrum quorum quenching activity

    Science.gov (United States)

    Muras, Andrea; Mayer, Celia; Romero, Manuel; Camino, Tamara; Ferrer, Maria D.; Mira, Alex; Otero, Ana

    2018-01-01

    ABSTRACT Background: Previous studies have suggested the quorum sensing signal AI-2 as a potential target to prevent the biofilm formation by Streptococcus mutans, a pathogen involved in tooth decay. Objective: To obtain inhibition of biofilm formation by S. mutans by extracts obtained from the marine bacterium Tenacibaculum sp. 20J interfering with the AI-2 quorum sensing system. Design: The AI-2 inhibitory activity was tested with the biosensors Vibrio harveyi BB170 and JMH597. S. mutans ATCC25175 biofilm formation was monitored using impedance real-time measurements with the xCELLigence system®, confocal laser microscopy, and the crystal violet quantification method. Results: The addition of the cell extract from Tenacibaculum sp. 20J reduced biofilm formation in S. mutans ATCC25175 by 40–50% compared to the control without significantly affecting growth. A decrease of almost 40% was also observed in S. oralis DSM20627 and S. dentisani 7747 biofilms. Conclusions: The ability of Tenacibaculum sp. 20J to interfere with AI-2 and inhibit biofilm formation in S. mutans was demonstrated. The results indicate that the inhibition of quorum sensing processes may constitute a suitable strategy for inhibiting dental plaque formation, although additional experiments using mixed biofilm models would be required. PMID:29410771

  10. Flagellin and F4 fimbriae have opposite effects on biofilm formation and quorum sensing in F4ac+ enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Zhou, Mingxu; Guo, Zhiyan; Yang, Yang; Duan, Qiangde; Zhang, Qi; Yao, Fenghua; Zhu, Jun; Zhang, Xinjun; Hardwidge, Philip R; Zhu, Guoqiang

    2014-01-10

    Bacteria that form biofilms are often highly resistant to antibiotics and are capable of evading the host immune system. To evaluate the role of flagellin and F4 fimbriae on biofilm formation by enterotoxigenic Escherichia coli (ETEC), we deleted the fliC (encoding the major flagellin protein) and/or the faeG (encoding the major subunit of F4 fimbriae) genes from ETEC C83902. Biofilm formation was reduced in the fliC mutant but increased in the faeG mutant, as compared with the wild-type strain. The expression of AI-2 quorum sensing associated genes was regulated in the fliC and faeG mutants, consistent with the biofilm formation of these strains. But, deleting fliC and/or faeG also inhibited AI-2 quorum sensing activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Auto Poisoning of the Respiratory Chain by a Quorum Sensing Regulated Molecule Favors Biofilm Formation and Antibiotic Tolerance

    Science.gov (United States)

    Hazan, Ronen; Que, Yok Ai; Maura, Damien; Strobel, Benjamin; Majcherczyk, Paul Anthony; Hopper, Laura Rose; Wilbur, David J.; Hreha, Teri N.; Barquera, Blanca; Rahme, Laurence G.

    2015-01-01

    Summary Bacterial programmed cell death and quorum sensing are direct examples of prokaryote group behaviors, wherein cells coordinate their actions to function cooperatively like one organism for the benefit of the whole culture. We demonstrate here that 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), a Pseudomonas aeruginosa quorum sensing -regulated low-molecular-weight excreted molecule, and triggers autolysis by self-perturbing the electron transfer reactions of the cytochrome bc1 complex. HQNO induces specific self-poisoning by disrupting the flow of electrons through the respiratory chain at the cytochrome bc1 complex, causing a leak of reducing equivalents to O2 whereby electrons that would normally be passed to cytochrome c are donated directly to O2. The subsequent mass production of reactive oxygen species (ROS) reduces membrane potential and disrupts membrane integrity, causing bacterial cell autolysis and DNA release. DNA subsequently promotes biofilm formation and increases antibiotic tolerance to beta-lactams, suggesting that HQNO-dependent cell autolysis is advantageous to the bacterial populations. These data both identify a new programmed cell death system, and a novel role for HQNO as a critical-inducer of biofilm formation and antibiotic tolerance. This newly identified pathway suggests intriguing mechanistic similarities with the initial mitochondrial-mediated steps of eukaryotic apoptosis. PMID:26776731

  12. Effect of organic acids on biofilm formation and quorum signaling of pathogens from fresh fruits and vegetables.

    Science.gov (United States)

    Amrutha, Balagopal; Sundar, Kothandapani; Shetty, Prathapkumar Halady

    2017-10-01

    Organic acids are known to be used as food preservatives due to their antimicrobial potential. This study evaluated the ability of three organic acids, namely, acetic acid, citric acid and lactic acid to manage E. coli and Salmonella sp. from fresh fruits and vegetables. Effect of these organic acids on biofilm forming ability and anti-quorum potential was also investigated. The effect of organic acids on inactivation of E. coli and Salmonella sp. on the surface of a selected vegetable (cucumber) was determined. The minimum inhibitory concentration of the organic acids were found to be 1.5, 2 and 0.2% in E. coli while it was observed to be 1, 1.5 and 1% in Salmonella sp. for acetic, citric and lactic acids respectively. Maximum inhibition of biofilm formation was recorded at 39.13% with lactic acid in E. coli and a minimum of 22.53% with citric acid in Salmonella sp. EPS production was affected in E. coli with lactic acid showing reduction by 13.42% while citric acid and acetic acid exhibited only 6.25% and 10.89% respectively. Swimming and swarming patterns in E. coli was notably affected by both acetic and lactic acids. Lactic and acetic acids showed higher anti-quorum sensing (QS) potential when compared to citric acid. 2% lactic acid showed a maximum inhibition of violacein production by 37.7%. Organic acids can therefore be used as potential quorum quenching agents in food industry. 2% lactic acid treatment on cucumber demonstrated that it was effective in inactivating E. coli and Salmonella sp. There was 1 log reduction in microbial count over a period of 6 days after the lactic acid treatment. Thus, organic acids can act as effective potential sanitizers in reducing the microbial load associated with fresh fruits and vegetables. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Streptococcus gordonii LuxS/autoinducer-2 quorum-sensing system modulates the dual-species biofilm formation with Streptococcus mutans.

    Science.gov (United States)

    Wang, Xiao; Li, Xiaolan; Ling, Junqi

    2017-07-01

    Dental plaques are mixed-species biofilms that are related to the development of dental caries. Streptococcus mutans (S. mutans) is an important cariogenic bacterium that forms mixed-species biofilms with Streptococcus gordonii (S. gordonii), an early colonizer of the tooth surface. The LuxS/autoinducer-2(AI-2) quorum sensing system is involved in the regulation of mixed-species biofilms, and AI-2 is proposed as a universal signal for the interaction between bacterial species. In this work, a S. gordonii luxS deficient strain was constructed to investigate the effect of the S. gordonii luxS gene on dual-species biofilm formed by S. mutans and S. gordonii. In addition, AI-2 was synthesized in vitro by incubating recombinant LuxS and Pfs enzymes of S. gordonii together. The effect of AI-2 on S. mutans single-species biofilm formation and cariogenic virulence gene expression were also assessed. The results showed that luxS disruption in S. gordonii altered dual-species biofilm formation, architecture, and composition, as well as the susceptibility to chlorhexidine. And the in vitro synthesized AI-2 had a concentration-dependent effect on S. mutans biofilm formation and virulence gene expression. These findings indicate that LuxS/AI-2 quorum-sensing system of S. gordonii plays a role in regulating the dual-species biofilm formation with S. mutans. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 2-Furaldehyde diethyl acetal from tender coconut water (Cocos nucifera) attenuates biofilm formation and quorum sensing-mediated virulence of Chromobacterium violaceum and Pseudomonas aeruginosa.

    Science.gov (United States)

    Sethupathy, Sivasamy; Nithya, Chari; Pandian, Shunmugiah Karutha

    2015-01-01

    The aim of this study was to evaluate the anti-biofilm and quorum sensing inhibitory (QSI) potential of tender coconut water (TCW) against Chromobacterium violaceum and Pseudomonas aeruginosa. TCW significantly inhibited the QS regulated violacein, virulence factors and biofilm production without affecting their growth. qRT-PCR analysis revealed the down-regulation of autoinducer synthase, transcriptional regulator and virulence genes. Mass-spectrometric analysis of a petroleum ether extract of the TCW hydrolyte revealed that 2-furaldehyde diethyl acetal (2FDA) and palmitic acid (PA) are the major compounds. In vitro bioassays confirmed the ability of 2FDA to inhibit the biofilm formation and virulence factors. In addition, the combination of PA with 2FDA resulted in potent inhibition of biofilm formation and virulence factors. The results obtained strongly suggest that TCW can be exploited as a base for designing a novel antipathogenic drug formulation to treat biofilm mediated infections caused by P. aeruginosa.

  15. Leaf Extracts of Mangifera indica L. Inhibit Quorum Sensing – Regulated Production of Virulence Factors and Biofilm in Test Bacteria

    Directory of Open Access Journals (Sweden)

    Iqbal Ahmad

    2017-04-01

    Full Text Available Quorum sensing (QS is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains. It was further correlated with the biofilm inhibition and confirmed by electron microscopy. Phytochemical analysis was carried out using ultra performance liquid chromatography (UPLC and gas chromatography–mass spectrometry (GC-MS analysis. In vitro evaluation of anti-QS activity of ML extracts against Chromobacterium violaceum revealed promising dose-dependent interference in violacein production, by methanol extract. QS inhibitory activity is also demonstrated by reduction in elastase (76%, total protease (56%, pyocyanin (89%, chitinase (55%, exopolysaccharide production (58% and swarming motility (74% in Pseudomonas aeruginosa PAO1 at 800 μg/ml concentration. Biofilm formation by P. aeruginosa PAO1 and Aeromonas hydrophila WAF38 was reduced considerably (36–82% over control. The inhibition of biofilm was also observed by scanning electron microscopy. Moreover, ML extracts significantly reduced mortality of Caenorhabditis elegans pre-infected with PAO1 at the tested concentration. Phytochemical analysis of active extracts revealed very high content of phenolics in methanol extract and a total of 14 compounds were detected by GC-MS and UPLC. These findings suggest that phytochemicals from the ML could provide bioactive anti-infective and needs further investigation to isolate and uncover their therapeutic efficacy.

  16. Quorum-sensing regulation governs bacterial adhesion, biofilm development, and host colonization in Pantoea stewartii subspecies stewartii.

    Science.gov (United States)

    Koutsoudis, Maria D; Tsaltas, Dimitrios; Minogue, Timothy D; von Bodman, Susanne B

    2006-04-11

    The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and development of spatially defined, 3D biofilms. Second, a nonvirulent mutant lacking the esaI gene adheres strongly to surfaces and develops densely packed, less structurally defined biofilms in vitro. This strain appears to be arrested in a low cell density developmental mode. Exposure of this strain to exogenous N-acyl-homoserine lactone counteracts this adhesion phenotype. Third, QS mutants lacking the EsaR repressor attach poorly to surfaces and form amorphous biofilms heavily enmeshed in excess EPS. Fourth, the WT strain disseminates efficiently within the xylem, primarily in a basipetal direction. In contrast, the two QS mutant strains remain largely localized at the site of infection. Fifth, and most significantly, epifluorescence microscopic imaging of infected leaf tissue and excised xylem vessels reveals that the bacteria colonize the xylem with unexpected specificity, particularly toward the annular rings and spiral secondary wall thickenings of protoxylem, as opposed to indiscriminate growth to fill the xylem lumen. These observations are significant to bacterial plant pathogenesis in general and may reveal targets for disease control.

  17. Leaf Extracts of Mangifera indica L. Inhibit Quorum Sensing – Regulated Production of Virulence Factors and Biofilm in Test Bacteria

    Science.gov (United States)

    Husain, Fohad M.; Ahmad, Iqbal; Al-thubiani, Abdullah S.; Abulreesh, Hussein H.; AlHazza, Ibrahim M.; Aqil, Farrukh

    2017-01-01

    Quorum sensing (QS) is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango) has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML) extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains. It was further correlated with the biofilm inhibition and confirmed by electron microscopy. Phytochemical analysis was carried out using ultra performance liquid chromatography (UPLC) and gas chromatography–mass spectrometry (GC-MS) analysis. In vitro evaluation of anti-QS activity of ML extracts against Chromobacterium violaceum revealed promising dose-dependent interference in violacein production, by methanol extract. QS inhibitory activity is also demonstrated by reduction in elastase (76%), total protease (56%), pyocyanin (89%), chitinase (55%), exopolysaccharide production (58%) and swarming motility (74%) in Pseudomonas aeruginosa PAO1 at 800 μg/ml concentration. Biofilm formation by P. aeruginosa PAO1 and Aeromonas hydrophila WAF38 was reduced considerably (36–82%) over control. The inhibition of biofilm was also observed by scanning electron microscopy. Moreover, ML extracts significantly reduced mortality of Caenorhabditis elegans pre-infected with PAO1 at the tested concentration. Phytochemical analysis of active extracts revealed very high content of phenolics in methanol extract and a total of 14 compounds were detected by GC-MS and UPLC. These findings suggest that phytochemicals from the ML could provide bioactive anti-infective and needs further investigation to isolate and uncover their therapeutic efficacy. PMID:28484444

  18. Effect of salinity and incubation time of planktonic cells on biofilm formation, motility, exoprotease production, and quorum sensing of Aeromonas hydrophila.

    Science.gov (United States)

    Jahid, Iqbal Kabir; Mizan, Md Furkanur Rahaman; Ha, Angela J; Ha, Sang-Do

    2015-08-01

    The aim of this study was to determine the effect of salinity and age of cultures on quorum sensing, exoprotease production, and biofilm formation by Aeromonas hydrophila on stainless steel (SS) and crab shell as substrates. Biofilm formation was assessed at various salinities, from fresh (0%) to saline water (3.0%). For young and old cultures, planktonic cells were grown at 30 °C for 24 h and 96 h, respectively. Biofilm formation was assessed on SS, glass, and crab shell; viable counts were determined in R2A agar for SS and glass, but Aeromonas-selective media was used for crab shell samples to eliminate bacterial contamination. Exoprotease activity was assessed using a Fluoro™ protease assay kit. Quantification of acyl-homoserine lactone (AHL) was performed using the bioreporter strain Chromobacterium violaceum CV026 and the concentration was confirmed using high-performance liquid chromatography (HPLC). The concentration of autoinducer-2 (AI-2) was determined with Vibrio harveyi BB170. The biofilm structure at various salinities (0-3 %) was assessed using field emission electron microscopy (FESEM). Young cultures of A. hydrophila grown at 0-0.25% salinity showed gradual increasing of biofilm formation on SS, glass and crab shell; swarming and swimming motility; exoproteases production, AHL and AI-2 quorum sensing; while all these phenotypic characters reduced from 0.5 to 3.0% salinity. The FESEM images also showed that from 0 to 0.25% salinity stimulated formation of three-dimensional biofilm structures that also broke through the surface by utilizing the chitin surfaces of crab, while 3% salinity stimulated attachment only for young cultures. However, in marked contrast, salinity (0.1-3%) had no effect on the stimulation of biofilm formation or on phenotypic characters for old cultures. However, all concentrations reduced biofilm formation, motility, protease production and quorum sensing for old culture. Overall, 0-0.25% salinity enhanced biofilm formation

  19. Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Prateeksha

    2017-03-01

    Full Text Available Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS, a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors and polyphenols of honey (HP for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery.

  20. Staphylococcus aureus Quorum Regulator SarA Targeted Compound, 2-[(Methylaminomethyl]phenol Inhibits Biofilm and Down-Regulates Virulence Genes

    Directory of Open Access Journals (Sweden)

    P. Balamurugan

    2017-07-01

    Full Text Available Staphylococcus aureus is a widely acknowledged Gram-positive pathogen for forming biofilm and virulence gene expressions by quorum sensing (QS, a cell to cell communication process. The quorum regulator SarA of S. aureus up-regulates the expression of many virulence factors including biofilm formation to mediate pathogenesis and evasion of the host immune system in the late phases of growth. Thus, inhibiting the production or blocking SarA protein might influence the down-regulation of biofilm and virulence factors. In this context, here we have synthesized 2-[(Methylaminomethyl]phenol, which was specifically targeted toward the quorum regulator SarA through in silico approach in our previous study. The molecule has been evaluated in vitro to validate its antibiofilm activity against clinical S. aureus strains. In addition, antivirulence properties of the inhibitor were confirmed with the observation of a significant reduction in the expression of representative virulence genes like fnbA, hla and hld that are governed under S. aureus QS. Interestingly, the SarA targeted inhibitor showed negligible antimicrobial activity and markedly reduced the minimum inhibitory concentration of conventional antibiotics when used in combination making it a more attractive lead for further clinical tests.

  1. Antimicrobial properties of Kalanchoe blossfeldiana: a focus on drug resistance with particular reference to quorum sensing-mediated bacterial biofilm formation.

    Science.gov (United States)

    Sarkar, Ratul; Mondal, Chaitali; Bera, Rammohan; Chakraborty, Sumon; Barik, Rajib; Roy, Paramita; Kumar, Alekh; Yadav, Kirendra K; Choudhury, Jayanta; Chaudhary, Sushil K; Samanta, Samir K; Karmakar, Sanmoy; Das, Satadal; Mukherjee, Pulok K; Mukherjee, Joydeep; Sen, Tuhinadri

    2015-07-01

    This study attempts to investigate the antimicrobial properties of Kalanchoe blossfeldiana with a particular reference to quorum sensing (QS)-mediated biofilm formation. The methanol extract of K. blossfeldiana leaves (MEKB) was evaluated for antimicrobial properties including QS-controlled production of biofilm (including virulence factor, motility and lactone formation) in Pseudomonas aeruginosa. Methanol extract of K. blossfeldiana was also evaluated for anti-cytokine (tumour necrosis factor-alpha, interleukin-6 and interleukin-1 beta) properties in peripheral blood mononuclear cells (PBMC). Methanol extract of K. blossfeldiana exhibited antimicrobial effect on clinical isolates, as well as standard reference strains. Pseudomonas aeruginosa exposed to MEKB (subminimum inhibitory concentration (MIC)) displayed reduced biofilm formation, whereas supra-MIC produced destruction of preformed biofilms. Methanol extract of K. blossfeldiana reduced the secretion of virulence factors (protease and pyoverdin) along with generation of acyl homoserine lactone (AHL). Confocal laser scanning microscopy images indicate reduction of biofilm thickness. The extract also reduced cytokine formation in lipopolysaccharide-stimulated PBMC. Kalanchoe blossfeldiana was found to interfere with AHL production, which in turn may be responsible for downregulating QS-mediated production of biofilm and virulence. This first report on the antibiofilm and anticytokine properties of this plant may open up new vistas for future exploration of this plant for combating biofilm-related resistant infections. © 2015 Royal Pharmaceutical Society.

  2. Recent Advances in the Study of Marine Microbial Biofilm: From the Involvement of Quorum Sensing in Its Production up to Biotechnological Application of the Polysaccharide Fractions

    Directory of Open Access Journals (Sweden)

    Paola Di Donato

    2016-05-01

    Full Text Available The present review will explore the most relevant findings on marine microbial biofilm, with particular attention towards its polysaccharide fraction, namely exopolysaccharide (EPS. EPSs of microbial origin are ubiquitous in nature, possess unique properties and can be isolated from the bacteria living in a variety of habitats, including fresh water or marine environments, extreme environments or different soil ecosystems. These biopolymers have many application in the field of biotechnology. Several studies showed that the biofilm formation is closely related to quorum sensing (QS systems, which is a mechanism relying on the production of small molecules defined as “autoinducers” that bacteria release in the surrounding environment where they accumulate. In this review, the involvement of microbial chemical communication, by QS mechanism, in the formation of marine biofilm will also be discussed.

  3. Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm.

    Science.gov (United States)

    Al-Shabib, Nasser A; Husain, Fohad Mabood; Ahmed, Faheem; Khan, Rais Ahmad; Ahmad, Iqbal; Alsharaeh, Edreese; Khan, Mohd Shahnawaz; Hussain, Afzal; Rehman, Md Tabish; Yusuf, Mohammad; Hassan, Iftekhar; Khan, Javed Masood; Ashraf, Ghulam Md; Alsalme, Ali Mohammed; Al-Ajmi, Mohamed F; Tarasov, Vadim V; Aliev, Gjumrakch

    2016-12-05

    Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative.

  4. Attenuation of Pseudomonas aeruginosa quorum sensing, virulence and biofilm formation by extracts of Andrographis paniculata.

    Science.gov (United States)

    Banerjee, Malabika; Moulick, Soumitra; Bhattacharya, Kunal Kumar; Parai, Debaprasad; Chattopadhyay, Subrata; Mukherjee, Samir Kumar

    2017-12-01

    Quorum-sensing (QS) is known to play an essential role in regulation of virulence factors and toxins during Pseudomonas aeruginosa infection which may frequently cause antibiotic resistance and hostile outcomes of inflammatory injury. Therefore, it is an urgent need to search for a novel agent with low risk of resistance development that can target QS and inflammatory damage prevention as well. Andrographis paniculata, a herbaceous plant under the family Acanthaceae, native to Asian countries and also cultivated in Scandinavia and some parts of Europe, has a strong traditional usage with its known antibacterial, anti-inflammatory, antipyretic, antiviral and antioxidant properties. In this study, three different solvent extracts (viz., chloroform, methanol and aqueous) of A. paniculata were examined for their anti-QS and anti-inflammatory activities. Study was carried out to assess the effect on some selected QS-regulatory genes at transcriptional level using Real Time-PCR. In addition, ability to attenuate MAPK pathways upon P. aeruginosa infection was performed to check its potential anti-inflammatory activity. Chloroform and methanol extracts showed significant reduction (p paniculata extracts inhibit QS in P. aeruginosa and exhibit anti-inflammatory activities, therefore it represents itself as a prospective therapeutic agent against P. aeruginosa infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The symbiotic biofilm of Sinorhizobium fredii SMH12, necessary for successful colonization and symbiosis of Glycine max cv Osumi, is regulated by Quorum Sensing systems and inducing flavonoids via NodD1.

    Directory of Open Access Journals (Sweden)

    Francisco Pérez-Montaño

    Full Text Available Bacterial surface components, especially exopolysaccharides, in combination with bacterial Quorum Sensing signals are crucial for the formation of biofilms in most species studied so far. Biofilm formation allows soil bacteria to colonize their surrounding habitat and survive common environmental stresses such as desiccation and nutrient limitation. This mode of life is often essential for survival in bacteria of the genera Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Rhizobium. The role of biofilm formation in symbiosis has been investigated in detail for Sinorhizobium meliloti and Bradyrhizobium japonicum. However, for S. fredii this process has not been studied. In this work we have demonstrated that biofilm formation is crucial for an optimal root colonization and symbiosis between S. fredii SMH12 and Glycine max cv Osumi. In this bacterium, nod-gene inducing flavonoids and the NodD1 protein are required for the transition of the biofilm structure from monolayer to microcolony. Quorum Sensing systems are also required for the full development of both types of biofilms. In fact, both the nodD1 mutant and the lactonase strain (the lactonase enzyme prevents AHL accumulation are defective in soybean root colonization. The impairment of the lactonase strain in its colonization ability leads to a decrease in the symbiotic parameters. Interestingly, NodD1 together with flavonoids activates certain quorum sensing systems implicit in the development of the symbiotic biofilm. Thus, S. fredii SMH12 by means of a unique key molecule, the flavonoid, efficiently forms biofilm, colonizes the legume roots and activates the synthesis of Nod factors, required for successfully symbiosis.

  6. The natural antimicrobial carvacrol inhibits quorum sensing in Chromobacterium violaceum and reduces bacterial biofilm formation at sub-lethal concentrations

    NARCIS (Netherlands)

    Burt, Sara A|info:eu-repo/dai/nl/140114432; Ojo-Fakunle, Victoria T A; Woertman, Jenifer; Veldhuizen, Edwin J A|info:eu-repo/dai/nl/19545264X

    2014-01-01

    The formation of biofilm by bacteria confers resistance to biocides and presents problems in medical and veterinary clinical settings. Here we report the effect of carvacrol, one of the major antimicrobial components of oregano oil, on the formation of biofilms and its activity on existing biofilms.

  7. Quorum Sensing of Periodontal Pathogens

    Directory of Open Access Journals (Sweden)

    Darije Plančak

    2015-01-01

    Full Text Available The term ‘quorum sensing’ describes intercellular bacterial communication which regulates bacterial gene expression according to population cell density. Bacteria produce and secrete small molecules, named autoinducers, into the intercellular space. The concentration of these molecules increases as a function of population cell density. Once the concentration of the stimulatory threshold is reached, alteration in gene expression occurs. Gram-positive and Gram-negative bacteria possess different types of quorum sensing systems. Canonical LuxI/R-type/acyl homoserine lactone mediated quorum sensing system is the best studied quorum sensing circuit and is described in Gram-negative bacteria which employ it for inter-species communication mostly. Grampositive bacteria possess a peptide-mediated quorum sensing system. Bacteria can communicate within their own species (intra-species but also between species (inter-species, for which they employ an autoinducer-2 quorum sensing system which is called the universal language of the bacteria. Periodontal pathogenic bacteria possess AI-2 quorum sensing systems. It is known that they use it for regulation of biofilm formation, iron uptake, stress response and virulence factor expression. A better understanding of bacterial communication mechanisms will allow the targeting of quorum sensing with quorum sensing inhibitors to prevent and control disease.

  8. The cep quorum-sensing system of Burkholderia cepacia H111 controls biofilm formation and swarming motility

    DEFF Research Database (Denmark)

    Huber, B.; Riedel, K.; Hentzer, Morten

    2001-01-01

    Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, the isolation of random mini-Tn5 insertion mutants of B. cepacia H111 defective in biofilm formation on an abiotic surface is reported. It is demons......Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, the isolation of random mini-Tn5 insertion mutants of B. cepacia H111 defective in biofilm formation on an abiotic surface is reported...

  9. 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

  10. Characterisation of two quorum sensing systems in the endophytic Serratia plymuthica strain G3: differential control of motility and biofilm formation according to life-style.

    Science.gov (United States)

    Liu, Xiaoguang; Jia, Jinli; Popat, Roman; Ortori, Catherine A; Li, Jun; Diggle, Stephen P; Gao, Kexiang; Cámara, Miguel

    2011-02-01

    N-acylhomoserine lactone (AHL)-based quorum sensing (QS) systems have been described in many plant-associated Gram-negative bacteria to control certain beneficial phenotypic traits, such as production of biocontrol factors and plant growth promotion. However, the role of AHL-mediated signalling in the endophytic strains of plant-associated Serratia is still poorly understood. An endophytic Serratia sp. G3 with biocontrol potential and high levels of AHL signal production was isolated from the stems of wheat and the role of QS in this isolate was determined. Strain G3 classified as Serratia plymuthica based on 16S rRNA was subjected to phylogenetic analysis. Using primers to conserved sequences of luxIR homologues from the Serratia genus, splIR and spsIR from the chromosome of strain G3 were cloned and sequenced. AHL profiles from strain G3 and Escherichia coli DH5α expressing splI or spsI from recombinant plasmids were identified by liquid chromatography-tandem mass spectrometry. This revealed that the most abundant AHL signals produced by SplI in E. coli were N-3-oxo-hexanoylhomoserine lactone (3-oxo-C6-HSL), N-3-oxo-heptanoylhomoserine lactone (3-oxo-C7-HSL), N-3-hydroxy-hexanoylhomoserine lactone (3-hydroxy-C6-HSL), N-hexanoylhomoserine lactone (C6-HSL), and N-heptanoyl homoserine lactone (C7-HSL); whereas SpsI was primarily responsible for the synthesis of N-butyrylhomoserine lactone (C4-HSL) and N-pentanoylhomoserine lactone (C5-HSL). Furthermore, a quorum quenching analysis by heterologous expression of the Bacillus A24 AiiA lactonase in strain G3 enabled the identification of the AHL-regulated biocontrol-related traits. Depletion of AHLs with this lactonase resulted in altered adhesion and biofilm formation using a microtiter plate assay and flow cells coupled with confocal laser scanning microscopy respectively. This was different from the closely related S. plymuthica strains HRO-C48 and RVH1, where biofilm formation for both strains is AHL

  11. Characterisation of two quorum sensing systems in the endophytic Serratia plymuthica strain G3: differential control of motility and biofilm formation according to life-style

    Directory of Open Access Journals (Sweden)

    Li Jun

    2011-02-01

    Full Text Available Abstract Background N-acylhomoserine lactone (AHL-based quorum sensing (QS systems have been described in many plant-associated Gram-negative bacteria to control certain beneficial phenotypic traits, such as production of biocontrol factors and plant growth promotion. However, the role of AHL-mediated signalling in the endophytic strains of plant-associated Serratia is still poorly understood. An endophytic Serratia sp. G3 with biocontrol potential and high levels of AHL signal production was isolated from the stems of wheat and the role of QS in this isolate was determined. Results Strain G3 classified as Serratia plymuthica based on 16S rRNA was subjected to phylogenetic analysis. Using primers to conserved sequences of luxIR homologues from the Serratia genus, splIR and spsIR from the chromosome of strain G3 were cloned and sequenced. AHL profiles from strain G3 and Escherichia coli DH5α expressing splI or spsI from recombinant plasmids were identified by liquid chromatography-tandem mass spectrometry. This revealed that the most abundant AHL signals produced by SplI in E. coli were N-3-oxo-hexanoylhomoserine lactone (3-oxo-C6-HSL, N-3-oxo-heptanoylhomoserine lactone (3-oxo-C7-HSL, N-3-hydroxy-hexanoylhomoserine lactone (3-hydroxy-C6-HSL, N-hexanoylhomoserine lactone (C6-HSL, and N-heptanoyl homoserine lactone (C7-HSL; whereas SpsI was primarily responsible for the synthesis of N-butyrylhomoserine lactone (C4-HSL and N-pentanoylhomoserine lactone (C5-HSL. Furthermore, a quorum quenching analysis by heterologous expression of the Bacillus A24 AiiA lactonase in strain G3 enabled the identification of the AHL-regulated biocontrol-related traits. Depletion of AHLs with this lactonase resulted in altered adhesion and biofilm formation using a microtiter plate assay and flow cells coupled with confocal laser scanning microscopy respectively. This was different from the closely related S. plymuthica strains HRO-C48 and RVH1, where biofilm formation

  12. Phage-mediated dispersal of biofilm and distribution of bacterial virulence genes is induced by quorum sensing.

    Directory of Open Access Journals (Sweden)

    Friederike S Rossmann

    2015-02-01

    Full Text Available The microbiome and the phage meta-genome within the human gut are influenced by antibiotic treatments. Identifying a novel mechanism, here we demonstrate that bacteria use the universal communication molecule AI-2 to induce virulence genes and transfer them via phage release. High concentrations (i.e. 100 μM of AI-2 promote dispersal of bacteria from already established biofilms, and is associated with release of phages capable of infecting other bacteria. Enterococcus faecalis V583ΔABC harbours 7 prophages in its genome, and a mutant deficient in one of these prophages (i.e. prophage 5 showed a greatly reduced dispersal of biofilm. Infection of a probiotic E. faecalis strain without lytic prophages with prophage 5 resulted in increased biofilm formation and also in biofilm dispersal upon induction with AI-2. Infection of the probiotic E. faecalis strain with phage-containing supernatants released through AI-2 from E. faecalis V583ΔABC resulted in a strong increase in pathogenicity of this strain. The polylysogenic probiotic strain was also more virulent in a mouse sepsis model and a rat endocarditis model. Both AI-2 and ciprofloxacin lead to phage release, indicating that conditions in the gastrointestinal tract of hospitalized patients treated with antibiotics might lead to distribution of virulence genes to apathogenic enterococci and possibly also to other commensals or even to beneficial probiotic strains.

  13. Piper betle and its bioactive metabolite phytol mitigates quorum sensing mediated virulence factors and biofilm of nosocomial pathogen Serratia marcescens in vitro.

    Science.gov (United States)

    Srinivasan, Ramanathan; Devi, Kannan Rama; Kannappan, Arunachalam; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2016-12-04

    Piper betle, a tropical creeper plant belongs to the family Piperaceae. The leaves of this plant have been well known for their therapeutic, religious and ceremonial value in South and Southeast Asia. It has also been reported to possess several biological activities including antimicrobial, antioxidant, antinociceptive, antidiabetic, insecticidal and gastroprotective activities and used as a common ingredient in indigenous medicines. In Indian system of ayurvedic medicine, P. betle has been well recognized for its antiseptic properties and is commonly applied on wounds and lesions for its healing effects. To evaluate the anti-quorum sensing (anti-QS) and antibiofilm efficacy of P. betle and its bioactive metabolite phytol against Serratia marcescens. The P. betle ethyl acetate extract (PBE) was evaluated for its anti-QS efficacy against S. marcescens by assessing the prodigiosin and lipase production at 400 and 500µgml -1 concentrations. In addition, the biofilm biomass quantification assay was performed to evaluate the antibiofilm activity of PBE against S. marcescens. Besides, the influence of PBE on bacterial biofilm formation was assessed through microscopic techniques. The biofilm related phenomenons like exopolysaccharides (EPS) production, hydrophobicity and swarming motility were also examined to support the antibiofilm activity of PBE. Transcriptional analysis of QS regulated genes in S. marcescens was also done. Characterization of PBE was done by separation through column chromatography and identification of active metabolites by gas chromatography -mass spectrometry. The major compounds of active fractions such as hexadecanoic acid, eugenol and phytol were assessed for their anti-QS activity against S. marcescens. Further, the in vitro bioassays such as protease, biofilm and HI quantification were also carried out to confirm the anti-QS and antibiofilm potential of phytol in PBE. PBE inhibits QS mediated prodigiosin pigment production in S. marcescens

  14. Size of quorum sensing communities

    DEFF Research Database (Denmark)

    Ferkinghoff-Borg, Jesper; Sams, Thomas

    2014-01-01

    Ensembles of bacteria are able to coordinate their phenotypic behavior in accordance with the size, density, and growth state of the ensemble. This is achieved through production and exchange of diffusible signal molecules in a cell–cell regulatory system termed quorum sensing. In the generic....... For a disk-shaped biofilm the geometric factor is the horizontal dimension multiplied by the height, and the square of the height of the biofilm if there is significant flow above the biofilm. A remarkably simple factorized expression for the size is obtained, which separates the all-or-none ignition caused...

  15. Attenuation of quorum-sensing-dependent virulence factors and biofilm formation by medicinal plants against antibiotic resistant Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    P. Sankar Ganesh

    2018-01-01

    Full Text Available Pseudomonas aeruginosa use small signaling molecules such as acyl homoserine lactones (AHLs, which play an important role in release virulence factors and toxin for further establishment of host infection. Thus, involving with the QS system would provide alternative ways of preventing the pathogenicity. In the present study, totally six medicinal plants (Terminalia bellerica, Celastrus paniculatus, Kingiodendron pinnatum, Schleichera oleosa, Melastoma malabathricum, Garcinia gummi-gutta were screened for anti-QS activity using biomonitor strain of Chromobacterium violaceum CV12472. The primary screening of antimicrobial activity of all the plant extracts have inhibited the growth of tested bacterial species. Of these at the sub-minimum inhibitory concentration the methanol extract of T. bellerica (0.0625–0.5 mg/ml has significantly inhibited violacein production (20.07–66.22% in C. violaceum (CV12472. Consequently, the extract of T. bellerica has reduced the production of pyocyanin, exopolysaccharide and biofilm formation in P. aeruginosa strains. Fluorescence and scanning electron microscopy analysis confirmed the reduction of biofilm formation in P. aeruginosa strains when treated with T. bellerica. GC–MS analysis showed the active compounds inhibited the production of virulence factors of P. aeruginosa. The results suggest the possible use of this T. bellerica as an anti-QS and anti-biofilm agent to control Pseudomonas infection. Interference of QS provides an important means for the inhibition of bacterial virulence and thus aids in treatment strategies.

  16. Biofilms.

    Science.gov (United States)

    López, Daniel; Vlamakis, Hera; Kolter, Roberto

    2010-07-01

    The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. Using these bacteria as examples, we discuss the key features of biofilms as well as mechanisms by which extracellular signals trigger biofilm formation.

  17. Quorum signaling and sensing by nontypeable Haemophilus influenzae.

    Science.gov (United States)

    Swords, W Edward

    2012-01-01

    Quorum signals are diffusible factors produced by bacteria that coordinate communal responses. For nontypeable Haemophilus influenzae (NTHi), a series of recent papers indicate that production and sensing of quorum signals are determinants of biofilm formation/maturation and persistence in vivo. In this mini-review I will summarize the current knowledge about quorum signaling/sensing by this organism, and identify specific topics for additional study.

  18. Quorum signaling and sensing by nontypeable Haemophilus influenzae

    Directory of Open Access Journals (Sweden)

    W Edward Swords

    2012-07-01

    Full Text Available Quorum signals are diffusible factors produced by bacteria that coordinate communal responses. For Haemophilus influenzae, a series of recent papers indicate that production and sensing of quorum signals are determinants of biofilm formation/maturation and persistence in vivo. In this mini-review I will summarize the current knowledge about quorum signaling/sensing by H. influenzae, and identify specific topics for additional study.

  19. Biofilms

    OpenAIRE

    López, Daniel; Vlamakis, Hera; Kolter, Roberto

    2010-01-01

    The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and ...

  20. Quorum Systems

    DEFF Research Database (Denmark)

    Wattenhofer, Roger; Förster, Klaus-Tycho

    2016-01-01

    What happens if a single server is no longer powerful enough to service all your customers? The obvious choice is to add more servers and to use the majority approach (e.g. Paxos, Chapter 2) to guarantee consistency. However, even if you buy one million servers, a client still has to access more ...... study the theory behind overlapping sets, known as quorum systems....

  1. In vitro and in vivo effect of 2,6-Di-tert-butyl-4-methylphenol as an antibiofilm agent against quorum sensing mediated biofilm formation of Vibrio spp.

    Science.gov (United States)

    Santhakumari, Sivasubramanian; Jayakumar, Rengarajan; Logalakshmi, Ravichandran; Prabhu, Narayanan Marimuthu; Abdul Nazar, Abdul Kuthus; Karutha Pandian, Shunmugiah; Veera Ravi, Arumugam

    2018-05-25

    This study unveils the in vitro and in vivo antibiofilm potential of 2,6-Di-tert-butyl-4-methylphenol (DTBMP) from Chroococcus turgidus against Vibrio spp. In the preliminary study, cell free culture supernatant (CFCS) of C. turgidus inhibited the violacein production in biomarker strain Chromobacterium violaceum and its mutant strain CV026 in a dose dependent manner. The effective biofilm inhibitory concentration (BIC) of pure compound DTBMP from C. turgidus was identified as 250 μg/ml concentration in tested Vibrio species. Furthermore, DTBMP proved to effectively inhibit the bioluminescence production in V. harveyi and other biofilm related virulence traits such as exopolysaccharides (EPS) production, hydrophobicity index, swimming and swarming motility at its BIC concentration in three major pathogenic vibrios: V. harveyi, V. parahaemolyticus and V. vulnificus. The antibiofilm potential of DTBMP was validated through light, confocal laser scanning and scanning electron microscopic analyses. In addition, the non-bactericidal effect of DTBMP was determined through growth curve and 2,3-bis (2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Real-time PCR studies revealed the down-regulation of master quorum sensing (QS) regulator genes of V. harveyi such as luxR, luxS, luxP, luxQ and luxO on treatment with DTBMP. In vivo results confirmed that DTBMP augmented the survival rate of Litopenaeus vannamei larvae up to 75, 88 and 66% upon infection with V. harveyi, V. parahaemolyticus and V. vulnificus, respectively. The results of this study ascertain the promising effects of DTBMP as an antibiofilm agent, which could be positively explored to treat biofilm-associated vibrios infections in aquaculture. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Inhibition of quorum sensing and biofilm formation in Vibrio harveyi by 4-fluoro-DPD; a novel potent inhibitor of signalling.

    Science.gov (United States)

    Kadirvel, Manikandan; Fanimarvasti, Fariba; Forbes, Sarah; McBain, Andrew; Gardiner, John M; Brown, Gavin D; Freeman, Sally

    2014-05-21

    (S)-4,5-Dihydroxypentane-2,3-dione [(S)-DPD, (1)] is a precursor for , a quorum sensing signalling molecule for inter- and intra-species bacterial communication. The synthesis of its fluoro-analogue, 4-fluoro-5-hydroxypentane-2,3-dione () is reported. An intermediate in this route also enables a new, shorter synthesis of the native (S)-DPD. 4-Fluoro-DPD (2) completely inhibited bioluminescence and bacterial growth of Vibrio harveyi BB170 strain at 12.5 μM and 100 μM, respectively.

  3. Synthesis of (R)-norbgugaine and its potential as quorum sensing inhibitor against Pseudomonas aeruginosa

    Digital Repository Service at National Institute of Oceanography (India)

    Majik, M.S.; Naik, D.; Bhat, C.; Tilve, S.; Tilvi, S.; DeSouza, L.

    and cat hydrogenation as the key steps and its biological studies are reported for the first time. The synthesized norbgugaine was evaluated for inhibition of quorum sensing mediated virulence factors (motility, biofilm formation, pyocyanin pigmentation...

  4. Combination Therapy Strategy of Quorum Quenching Enzyme and Quorum Sensing Inhibitor in Suppressing Multiple Quorum Sensing Pathways of P. aeruginosa

    DEFF Research Database (Denmark)

    Fong, July; Zhang, Chaodong; Yang, Renliang

    2018-01-01

    The threat of antibiotic resistant bacteria has called for alternative antimicrobial strategies that would mitigate the increase of classical resistance mechanism. Many bacteria employ quorum sensing (QS) to govern the production of virulence factors and formation of drug-resistant biofilms. Targ...

  5. The Efficacy of the Quorum Sensing Inhibitor FS8 and Tigecycline in Preventing Prosthesis Biofilm in an Animal Model of Staphylococcal Infection

    Directory of Open Access Journals (Sweden)

    Andrea Giacometti

    2013-08-01

    Full Text Available We investigated the efficacy of tigecycline and FS8, alone or combined, in preventing prosthesis biofilm in a rat model of staphylococcal vascular graft infection. Graft infections were established in the back subcutaneous tissue of adult male Wistar rats by implantation of Dacron prostheses followed by topical inoculation with 2 x 107 colony-forming units of Staphylococcus aureus, strain Smith diffuse. The study included a control group, a contaminated group that did not receive any antibiotic prophylaxis, and three contaminated groups that received: (i intraperitoneal tigecycline, (ii FS8-soaked graft, and (iii tigecycline plus FS8-soaked graft, respectively. Each group included 15 animals. The infection burden was evaluated by using sonication and quantitative agar culture. Moreover, an in vitro binding-study was performed to quantify the how much FS8 was coated to the surface of the prosthesis. Tigecycline, combined with FS8, against the adherent bacteria showed MICs (2.00 mg/L and MBCs (4.00 mg/L four-fold lower with respect to tigecycline alone in in vitro studies. The rat groups treated with tigecycline showed the lowest bacterial numbers (4.4 x 104 ± 1.2 x 104 CFU/mL. The FS8-treated group showed a good activity and significant differences compared to control group with bacterial numbers of 6.8 x 104 ± 2.0 x 104 CFU/mL. A stronger inhibition of bacterial growth was observed in rats treated with a combined FS8 and tigecycline therapy than in those that were singly treated with bacterial numbers of 101 CFU/mL graft. In conclusion, the ability to affect biofilm formation as well, its property to be an antibiotic enhancer suggests FS8 as alternative or additional agent to use in conjunction with conventional antimicrobial for prevention of staphylococcal biofilm related infection.

  6. Quorum sensing and bacterial pathogenicity: From molecules to disease

    Directory of Open Access Journals (Sweden)

    Antariksh Deep

    2011-01-01

    Full Text Available Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.

  7. Trigonella foenum-graceum (Seed Extract Interferes with Quorum Sensing Regulated Traits and Biofilm Formation in the Strains of Pseudomonas aeruginosa and Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Fohad Mabood Husain

    2015-01-01

    Full Text Available Trigonella foenum-graecum L. (Fenugreek is an important plant of the Leguminosae family known to have medicinal properties. However, fraction based antiquorum sensing and antibiofilm activities have not been reported from this plant. In the present study T. foenum-graecum seed extract was sequentially fractionated and sub-MICs were tested for above activities. The methanol fraction of the extract demonstrated significant inhibition of AHL regulated virulence factors: protease, LasB elastase, pyocyanin production, chitinase, EPS, and swarming motility in Pseudomonas aeruginosa PAO1 and PAF79. Further, QS dependent virulence factor in the aquatic pathogen Aeromonas hydrophila WAF38 was also reduced. Application of T. foenum-graecum seed extract to PAO1, PAF79, and WAF38 decreased the biofilm forming abilities of the pathogens by significant levels. The extract also exhibited reduced AHL levels and subsequent downregulation of lasB gene. In vivo study showed an enhanced survival of PAO1-preinfected C. elegans after treatment with extract at 1 mg/mL. Further, the major compound detected by GC-MS, caffeine, reduced the production of QS regulated virulence factors and biofilm at 200 µg/mL concentration indicating its role in the activity of the methanol extract. The results of the present study reveal the potential anti-QS and antibiofilm property of T. foenum-graceum extract and caffeine.

  8. Qualitative and Quantitative Determination of Quorum Sensing Inhibition In Vitro

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Alhede, Maria; Hultqvist, Louise Dahl

    2018-01-01

    The formation of biofilms in conjunction with quorum sensing (QS) regulated expression of virulence by opportunistic pathogens contributes significantly to immune evasion and tolerance to a variety of antimicrobial treatments. The present protocol describes methods to determine the in vitro effic...

  9. Stigmatellin Y - An anti-biofilm compound from Bacillus subtilis BR4 possibly interferes in PQS-PqsR mediated quorum sensing system in Pseudomonas aeruginosa.

    Science.gov (United States)

    Boopathi, Seenivasan; Vashisth, Rajesh; Manoharan, Prabu; Kandasamy, Ruckmani; Sivakumar, Natesan

    2017-05-15

    Hitherto this is the first report pertaining to production of biofilm inhibitory compound(s) (BIC) from Bacillus subtilis BR4 against Pseudomonas aeruginosa (ATCC 27853) coupled with production optimization. In order to achieve this, combinations of media components were formulated by employing statistical tools such as Plackett-Burman analysis and central composite rotatable design (CCRD). It was evident that at 35mlL -1 glycerol and 3.8gL -1 casamino acid, anti-biofilm activity and production of extracellular protein significantly increased by 1.5-fold and 1.2-fold, respectively. These results corroborate that the combination of glycerol and casamino acid plays a key role in the production of BIC. Further, metabolic profiling of BIC was carried out using liquid chromatography/tandem mass spectrometry (LC-MS/MS) based on m/z value. The presence of Stigmatellin Y was predicted with monoisotopic neutral mass of 484.2825Da. In support of optimization study, higher production of BIC was confirmed in the optimized-media-grown BR4 (OPT-BR4) than in the ideal-media-grown BR4 (ID-BR4) by LC-MS/MS analysis. PqsR in P. aeruginosa is a potential target for anti-virulent therapy. Molecular docking study has revealed that Stigmatellin Y interacts with PqsR in the similar orientation like a cognate signal (PQS) and synthetic inhibitor. In addition, Stigmatellin Y was found to exhibit interaction with four more amino acid residues of PqsR to establish strong affinity. Stigmatellin Y thus might play a role of competitor for PQS to distract PQS-PqsR mediated communication in P. aeruginosa. The present investigation thus paves new avenues to develop anti-Pseudomonas virulent therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Novel linear polymers able to inhibit bacterial quorum sensing.

    Science.gov (United States)

    Cavaleiro, Eliana; Duarte, Ana Sofia; Esteves, Ana Cristina; Correia, António; Whitcombe, Michael J; Piletska, Elena V; Piletsky, Sergey A; Chianella, Iva

    2015-05-01

    Bacterial phenotypes, such as biofilm formation, antibiotic resistance and virulence expression, are associated with quorum sensing. Quorum sensing is a density-dependent regulatory system of gene expression controlled by specific signal molecules, such as N-acyl homoserine lactones (AHLs), produced and released by bacteria. This study reports the development of linear polymers capable to attenuate quorum sensing by adsorption of AHLs. Linear polymers were synthesized using MMA as backbone monomer and methacrylic acid and itaconic acid as functional monomers. Two different quorum sensing-controlled phenotypes, Vibrio fischeri bioluminescence and Aeromonas hydrophila biofilm formation, were evaluated to test the polymers' efficiency. Results showed that both phenotypes were significantly affected by the polymers, with the itaconic acid-containing material being more effective than the methacrylic acid one. The polymer inhibitory effects were reverted by the addition of lactones, confirming attenuation of quorum sensing through sequestration of signal molecules. The polymers also showed no cytotoxicity when tested using a mammalian cell line. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Design, Synthesis and Biological Evaluation of Quorum Sensing Modulators

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert

    to intercept the communication system by synthetic non-native ligands and thereby lower the pathogenesis and antibiotic tolerance of a bacterial biofilm. To identify new ligands with quorum sensing modulating activities, three types of AHL analogs were synthesized using different synthetic strategies....... Overall, 17 compounds were identified as quorum sensing activators with EC50 values in the low micromolar range. Two build/couple/pair strategies for the synthesis of structurally diverse small molecules are presented. In the first strategy, the Petasis 3-component reaction (Petasis 3-CR) of hydrazides...

  12. 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

  13. Evaluation of Enoyl-Acyl Carrier Protein Reductase Inhibitors as Pseudomonas aeruginosa Quorum-Quenching Reagents

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Sternberg, Claus

    2010-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen which is responsible for a wide range of infections. Production of virulence factors and biofilm formation by P. aeruginosa are partly regulated by cell-to-cell communication quorum-sensing systems. Identification of quorum-quenching reagents...... which block the quorum-sensing process can facilitate development of novel treatment strategies for P. aeruginosa infections. We have used molecular dynamics simulation and experimental studies to elucidate the efficiencies of two potential quorum-quenching reagents, triclosan and green tea...... epigallocatechin gallate (EGCG), which both function as inhibitors of the enoyl-acyl carrier protein (ACP) reductase (ENR) from the bacterial type II fatty acid synthesis pathway. Our studies suggest that EGCG has a higher binding affinity towards ENR of P. aeruginosa and is an efficient quorum-quenching reagent...

  14. Synergistic antibacterial efficacy of early combination treatment with tobramycin and quorum-sensing inhibitors against Pseudomonas aeruginosa in an intraperitoneal foreign-body infection mouse model

    DEFF Research Database (Denmark)

    Christensen, Louise; van Gennip, Maria; Jakobsen, Tim H

    2012-01-01

    Quorum sensing (QS)-deficient Pseudomonas aeruginosa biofilms formed in vitro are more susceptible to tobramycin than QS-proficient P. aeruginosa biofilms, and combination treatment with a QS inhibitor (QSI) and tobramycin shows synergistic effects on the killing of in vitro biofilms. We extended...

  15. Recent progresses on AI-2 bacterial quorum sensing inhibitors.

    Science.gov (United States)

    Zhu, Peng; Li, Minyong

    2012-01-01

    Quorum sensing (QS) is a communication procedure that predominates gene expression in response to cell density and fluctuations in the neighboring environment as a result of discerning molecules termed autoinducers (AIs). It has been embroiled that QS can govern bacterial behaviors such as the secretion of virulence factors, biofilm formation, bioluminescence production, conjugation, sporulation and swarming motility. Autoinducer 2 (AI-2), a QS signaling molecule brought up to be involved in interspecies communication, exists in both gram-negative and -positive bacteria. Therefore, novel approaches to interrupt AI-2 quorum sensing are being recognized as next generation antimicrobials. In the present review article, we summarized recent progresses on AI-2 bacterial quorum sensing inhibitors and discussed their potential as the antibacterial agents.

  16. Death and Survival in Streptococcus mutans: Differing Outcomes of a Quorum-Sensing Signalling Peptide

    Directory of Open Access Journals (Sweden)

    Vincent eLeung

    2015-10-01

    Full Text Available Bacteria are considered ‘social’ organisms able to communicate with one another using small hormone-like molecules (pheromones in a process called quorum-sensing. These signalling molecules increase in concentration as a function of bacterial cell density. For most human pathogens, quorum-sensing is critical for virulence and biofilm formation, and the opportunity to interfere with bacterial quorum-sensing could provide a sophisticated means for manipulating the composition of pathogenic biofilms, and possibly eradicating the infection. Streptococcus mutans is a well-characterized resident of the dental plaque biofilm, and is the major pathogen of dental caries (tooth decay. In S. mutans, its CSP quorum-sensing signalling peptide does not act as a classical quorum-sensing signal by accumulating passively in proportion to cell density. In fact, particular stresses such as those encountered in the oral cavity, induces the production of the CSP pheromone, suggesting that the pheromone most probably functions as a stress-inducible alarmone by triggering the signalling to the bacterial population to initiate an adaptive response that results in different phenotypic outcomes. This mini-review discusses two different CSP-induced phenotypes, bacterial ‘suicide’ and dormancy, and the underlying mechanisms by which S. mutans utilizes the same quorum-sensing signalling peptide to regulate two opposite phenotypes.

  17. Garlic as an inhibitor of Pseudomonas aeruginosa quorum sensing in cystic fibrosis--a pilot randomized controlled trial

    DEFF Research Database (Denmark)

    Smyth, Alan R; Cifelli, Paramita M; Ortori, Catharine A

    2010-01-01

    Pseudomonas aeruginosa forms biofilms in the cystic fibrosis lung. Quorum sensing (QS) controls biofilm maturation, immune evasion, antibiotic tolerance and virulence factor production. Garlic shows QS inhibitory activity in vitro and in animal models. We report the first clinical trial in man of...

  18. 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...

  19. Secondary metabolites produced by marine streptomyces as antibiofilm and quorum-sensing inhibitor of uropathogen Proteus mirabilis.

    Science.gov (United States)

    Younis, Khansa Mohammed; Usup, Gires; Ahmad, Asmat

    2016-03-01

    Quorum-sensing regulates bacterial biofilm formation and virulence factors, thereby making it an interesting target for attenuating pathogens. In this study, we investigated anti-biofilm and anti-quorum-sensing compounds from secondary metabolites of halophiles marine streptomyces against urinary catheter biofilm forming Proteus mirabilis without effect on growth viability. A total of 40 actinomycetes were isolated from samples collected from different places in Iraq including marine sediments and soil samples. Fifteen isolates identified as streptomyces and their supernatant screened as anti-quorum-sensing by inhibiting quorum-sensing regulated prodigiosin biosynthesis of Serratia marcescens strain Smj-11 as a reporter strain. Isolate Sediment Lake Iraq (sdLi) showed potential anti-quorum-sensing activity. Out of 35 clinical isolates obtained from Urinary catheter used by patient at the Universiti Kebangsaan Malaysia Medical Center, 22 isolates were characterized and identified as Proteus mirabilis. Isolate Urinary Catheter B4 (UCB4) showed the highest biofilm formation with highest resistance to used antibiotic and was chosen for further studies. Ethyl acetate secondary metabolites extract was produced from sdLi isolate. First, we determined the Minimum Inhibitory Concentration (MIC) of sdLi crude extract against UCB4 isolate, and all further experiments used concentrations below the MIC. Tests of subinhibitory concentrations of sdLi crude extract showed good inhibition against UCB4 isolate biofilm formation on urinary catheter and cover glass using Scanning electron microscopy and light microscopy respectively. The influence of sub-MIC of sdLi crude extract was also found to attenuate the quorum sensing (QS)-dependent factors such as hemolysin activity, urease activity, pH value, and motility of UCB4 isolate. Evidence is presented that these nontoxic secondary metabolites may act as antagonists of bacterial quorum sensing by competing with quorum-sensing signals

  20. The contribution of cell-cell signaling and motility to bacterial biofilm formation

    DEFF Research Database (Denmark)

    Shrout, Joshua D; Tolker-Nielsen, Tim; Givskov, Michael

    2011-01-01

    Many bacteria grow attached to a surface as biofilms. Several factors dictate biofilm formation, including responses by the colonizing bacteria to their environment. Here we review how bacteria use cell-cell signaling (also called quorum sensing) and motility during biofilm formation. Specifically...... gene expression important to the production of polysaccharides, rhamnolipid, and other virulence factors. Surface motility affects the assembly and architecture of biofilms, and some aspects of motility are also influenced by quorum sensing. While some genes and their function are specific to P....... aeruginosa, many aspects of biofilm development can be used as a model system to understand how bacteria differentially colonize surfaces....

  1. Microbial Biofilm as a Smart Material

    DEFF Research Database (Denmark)

    Garde, Christian; Welch, Martin; Ferkinghoff-Borg, Jesper

    2015-01-01

    Microbial biofilm colonies will in many cases form a smart material capable of responding to external threats dependent on their size and internal state. The microbial community accordingly switches between passive, protective, or attack modes of action. In order to decide which strategy to employ......, it is essential for the biofilm community to be able to sense its own size. The sensor designed to perform this task is termed a quorum sensor, since it only permits collective behaviour once a sufficiently large assembly of microbes have been established. The generic quorum sensor construct involves two genes...

  2. Bacterial biofilm and associated infections

    Directory of Open Access Journals (Sweden)

    Muhsin Jamal

    2018-01-01

    Full Text Available Microscopic entities, microorganisms that drastically affect human health need to be thoroughly investigated. A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living. Bacterial biofilms are usually pathogenic in nature and can cause nosocomial infections. The National Institutes of Health (NIH revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation. The process of biofilm formation consists of many steps, starting with attachment to a living or non-living surface that will lead to formation of micro-colony, giving rise to three-dimensional structures and ending up, after maturation, with detachment. During formation of biofilm several species of bacteria communicate with one another, employing quorum sensing. In general, bacterial biofilms show resistance against human immune system, as well as against antibiotics. Health related concerns speak loud due to the biofilm potential to cause diseases, utilizing both device-related and non-device-related infections. In summary, the understanding of bacterial biofilm is important to manage and/or to eradicate biofilm-related diseases. The current review is, therefore, an effort to encompass the current concepts in biofilm formation and its implications in human health and disease.

  3. Quorum sensing: a quantum perspective.

    Science.gov (United States)

    Majumdar, Sarangam; Pal, Sukla

    2016-09-01

    Quorum sensing is the efficient mode of communication in the bacterial world. After a lot of advancements in the classical theory of quorum sensing few basic questions of quorum sensing still remain unanswered. The sufficient progresses in quantum biology demands to explain these questions from the quantum perspective as non trivial quantum effects already have manifested in various biological processes like photosynthesis, magneto-reception etc. Therefore, it's the time to review the bacterial communications from the quantum view point. In this article we carefully accumulate the latest results and arguments to strengthen quantum biology through the addition of quorum sensing mechanism in the light of quantum mechanics.

  4. Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective

    Directory of Open Access Journals (Sweden)

    Benjamin Rémy

    2018-03-01

    Full Text Available Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs, as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs to block the action of AIs and quorum quenching (QQ enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.

  5. Viden, virkning og virke

    DEFF Research Database (Denmark)

    traditioner og vante tænkemåder. Relationerne mellem politiske og administrative beslutningstagere, sundhedsprofessionelle og patienter/borgere og deres foreninger forandres, og viden, politik og sundhed mødes og brydes på nye måder.   Har vi bevæget os fra en velfærdsstat til en konkurrencestat? Hvad betyder...

  6. Professionel kompetence og uddannelse

    DEFF Research Database (Denmark)

    Hedegaard, Karen Marie

    Specialet behandler forholdet mellem professionel kompetence og uddannelse gennem en undersøgelse og diskussion af teorier og forskning om professionsbegrebet i sociologien historisk og aktuelt, bl.a. Talcott Parsons, MaxWeber og Thomas Mathiesen, og diskuterer forskellige forståelser af professi......Specialet behandler forholdet mellem professionel kompetence og uddannelse gennem en undersøgelse og diskussion af teorier og forskning om professionsbegrebet i sociologien historisk og aktuelt, bl.a. Talcott Parsons, MaxWeber og Thomas Mathiesen, og diskuterer forskellige forståelser af...

  7. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Giantommaso Scarascia

    2016-12-01

    Full Text Available Sulfate-reducing bacteria (SRB are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

  8. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    KAUST Repository

    Scarascia, Giantommaso; Wang, Tiannyu; Hong, Pei-Ying

    2016-01-01

    Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

  9. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    KAUST Repository

    Scarascia, Giantommaso

    2016-12-15

    Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

  10. Garlic blocks quorum sensing and promotes rapid clearing of pulmonary Pseudomonas aeruginosa infections

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, P. Ø.; Rasmussen, Thomas Bovbjerg

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis patients. P. aeruginosa colonizes the lungs by forming biofilm microcolonies throughout the lung. Quorum sensing (QS) renders the biofilm bacteria highly tolerant......-treated biofilm. Garlic extract was administered as treatment for a mouse pulmonary infection model. Mice were treated with garlic extract or placebo for 7 days, with the initial 2 days being prophylactic before P. aeruginosa was instilled in the left lung of the mice. Bacteriology, mortality, histopathology...... and phagocytosis by PMNs, as well as leading to an improved outcome of pulmonary infections....

  11. 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...

  12. Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

    2006-09-20

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

  13. 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.

  14. Flavonoids Suppress Pseudomonas aeruginosa Virulence through Allosteric Inhibition of Quorum-sensing Receptors*

    Science.gov (United States)

    Paczkowski, Jon E.; Mukherjee, Sampriti; McCready, Amelia R.; Cong, Jian-Ping; Aquino, Christopher J.; Kim, Hahn; Henke, Brad R.; Smith, Chari D.; Bassler, Bonnie L.

    2017-01-01

    Quorum sensing is a process of cell-cell communication that bacteria use to regulate collective behaviors. Quorum sensing depends on the production, detection, and group-wide response to extracellular signal molecules called autoinducers. In many bacterial species, quorum sensing controls virulence factor production. Thus, disrupting quorum sensing is considered a promising strategy to combat bacterial pathogenicity. Several members of a family of naturally produced plant metabolites called flavonoids inhibit Pseudomonas aeruginosa biofilm formation by an unknown mechanism. Here, we explore this family of molecules further, and we demonstrate that flavonoids specifically inhibit quorum sensing via antagonism of the autoinducer-binding receptors, LasR and RhlR. Structure-activity relationship analyses demonstrate that the presence of two hydroxyl moieties in the flavone A-ring backbone are essential for potent inhibition of LasR/RhlR. Biochemical analyses reveal that the flavonoids function non-competitively to prevent LasR/RhlR DNA binding. Administration of the flavonoids to P. aeruginosa alters transcription of quorum sensing-controlled target promoters and suppresses virulence factor production, confirming their potential as anti-infectives that do not function by traditional bacteriocidal or bacteriostatic mechanisms. PMID:28119451

  15. Islam og Islamisme

    DEFF Research Database (Denmark)

    Simonsen, Jørgen Bæk

    2010-01-01

    En præsentation og en kritik af nyere international forskning i islam og islamisme Udgivelsesdato: Februar......En præsentation og en kritik af nyere international forskning i islam og islamisme Udgivelsesdato: Februar...

  16. The small nucleoid protein Fis is involved in Vibrio cholerae quorum sensing.

    Science.gov (United States)

    Lenz, Derrick H; Bassler, Bonnie L

    2007-02-01

    Quorum sensing is a process of cell-cell communication that bacteria use to relay information to one another about the cell density and species composition of the bacterial community. Quorum sensing involves the production, secretion and population-wide detection of small signalling molecules called autoinducers. This process allows bacteria to synchronize group behaviours and act as multicellular units. The human pathogen, Vibrio cholerae, uses quorum sensing to co-ordinate such complex behaviours as pathogenicity and biofilm formation. The quorum-sensing circuit of V. cholerae consists of two autoinducer/sensor systems, CAI-1/CqsS and AI-2/LuxPQ, and the VarS/A-CsrA/BCD growth-phase regulatory system. Genetic analysis suggests that an additional regulatory arm involved in quorum sensing exists in V. cholerae. All of these systems channel information into the histidine phosphotransfer protein, LuxU, and/or the response regulator, LuxO. LuxO, when phosphorylated, activates the expression of four genes encoding the Qrr (quorum regulatory RNAs) small RNAs (sRNAs). The Qrr sRNAs destabilize the hapR transcript encoding the master regulator of quorum sensing, HapR. Here we identify the nucleoid protein Fis as playing a major role in the V. cholerae quorum-sensing circuit. Fis fulfils the predictions required to be the putative additional component that inputs information into the cascade: its expression is regulated in a growth phase-dependent manner; it requires LuxO but acts independently of LuxU, and it regulates all four qrr genes and, in turn, HapR by directly binding to the qrr gene promoters and modulating their expression.

  17. [Biofilms and their significance in medical microbiology].

    Science.gov (United States)

    Cernohorská, L; Votava, M

    2002-11-01

    Microorganisms are able to adhere to various surfaces and to form there a three-dimensional structure known as biofilm. In biofilms, microbial cells show characteristics and behaviours different from those of plankton cells. Intercellular signalizations of the quorum-sensing type regulate interaction between members of the biofilm. Bacteria embedded in the biofilm can escape and form well known planktonic forms, that are obviously only a part of the bacterial life cycle. Bacteria adhere also to medically important surfaces such as catheters, either urinary or intravenous ones, artificial heart valves, orthopedic implants and so on and contribute to device-related infections like cystitis, catheter-related sepsis, endocarditis etc. Once a biofilm has been established on a surface, the bacteria harboured inside are less exposed to the host's immune response and less susceptible to antibiotics. As an important cause of nosocomial infections the biofilm must remain in the centre of the microbiologist's attention.

  18. Facework og mikrosociologi

    DEFF Research Database (Denmark)

    Hougaard, Tina Thode

    2014-01-01

    Troværdighed og tillid er alfa og omega, når virksomheder, organisationer og myndigheder kommunikerer med brugerne, men hvordan skabes denne troværdighed i de sociale medier - og hvordan opretholdes den?......Troværdighed og tillid er alfa og omega, når virksomheder, organisationer og myndigheder kommunikerer med brugerne, men hvordan skabes denne troværdighed i de sociale medier - og hvordan opretholdes den?...

  19. Processer og procesledelse

    DEFF Research Database (Denmark)

    Madsen, Benedicte

    Bogen udfolder, nuancerer og konkretiserer procesledelse ift. mentale, relationelle og organisatoriske processer. Eksempler på kapitel-overskrifter: Procesbegrebet, Rammesætning, Kontraktredskabet, Mødeledelse, Samtaler, Reflekterende positioner og processer, Konflikthåndtering og teamudvikling......, Invitation til det dialogiske rum - om at arbejde over og under stregen, og Mentale omstruktureringer....

  20. Videnarbejde og stress

    DEFF Research Database (Denmark)

    Buch, Anders; Andersen, Vibeke; Sørensen, Ole Henning

    . Videnarbejde kan for den enkelte være vejen til selvrealisering og begejstring, men rummer også i sig kimen til stress og udbrændthed. Og det er netop i spændingsfeltet - i kampen - mellem begejstring og belastning, at bogen ser stress i det moderne arbejdsliv, som en uoverensstemmelse mellem ydre krav og...

  1. Magt og anerkendelse

    DEFF Research Database (Denmark)

    Olesen, Carsten Frank

    2014-01-01

    Kapitlet omhandler dilemmaer i relation til døgnanbringelse af et barn, og samarbejdet/modarbejdet mellem familie og professionelle/system, hvor magt og anerkendelse er de analytiske nøglebegreber. Barnets reform og efterfølgende lovgivning til og med 2013 inddrages i relation, og søger at illust...

  2. Portfolio, refleksion og feedback

    DEFF Research Database (Denmark)

    Hansen, Jens Jørgen; Qvortrup, Ane; Christensen, Inger-Marie F.

    2017-01-01

    Denne leder definerer indledningsvist begrebet portfolio og gør rede for anvendelsesmuligheder i en uddannelseskontekst. Dernæst behandles portfoliometodens kvalitet og effekt for læring og undervisning og de centrale begreber refleksion, progression og feedback præsenteres og diskuteres. Herefter...

  3. Fluoride in dental biofilm and saliva

    DEFF Research Database (Denmark)

    Larsen, Line Staun

    Dette ph.d.-projekt bidrager med ny viden om fordelingen af fluorid i dental biofilm og saliva. For at udforske koncentrationen af fluorid i naturlig (in vivo) biofilmvæske, biofilmsediment og i saliva, blev der udført to meget forskellige kliniske studier. Resultaterne fra tværsnitsstudiet (Studie...... I), hos en stor gruppe mennesker (n=42) der konsulterede en tandklinik for behandling, bekræfter tidligere viden, at der findes en naturlig biologisk variation i fluoridkoncentrationerne i biofilm fra forskellige intra-orale regioner samt mellem biofilmvæske, biofilmsediment og saliva...... fluoridkoncentrationer i underkæbefronten, intermediære koncentrationer i alle tre overkæberegioner og de laveste koncentrationer i underkæbemolarregionerne. Begge studier viser at biofilmsedimentet indeholder størstedelen af fluorid i biofilm. Set i et bredere perspektiv viser fundene at der er et omvendt forhold...

  4. Mechanisms of quorum sensing and strategies for quorum sensing disruption in aquaculture pathogens.

    Science.gov (United States)

    Zhao, J; Chen, M; Quan, C S; Fan, S D

    2015-09-01

    In many countries, infectious diseases are a considerable threat to aquaculture. The pathogenicity of micro-organisms that infect aquaculture systems is closely related to the release of virulence factors and the formation of biofilms, both of which are regulated by quorum sensing (QS). Thus, QS disruption is a potential strategy for preventing disease in aquaculture systems. QS inhibitors (QSIs) not only inhibit the expression of virulence-associated genes but also attenuate the virulence of aquaculture pathogens. In this review, we discuss QS systems in important aquaculture pathogens and focus on the relationship between QS mechanisms and bacterial virulence in aquaculture. We further elucidate QS disruption strategies for targeting aquaculture pathogens. Four main types of QSIs that target aquaculture pathogens are discussed based on their mechanisms of action. © 2014 John Wiley & Sons Ltd.

  5. Development of Topical Treatment for Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers

    Science.gov (United States)

    2013-01-01

    dendrimers would provide added benefits as a delivery vehicle of QSI compounds to inhibit PA biofilms, by both increasing the transport of QSI as drug...Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers PRINCIPAL INVESTIGATOR...Development of Topical Treatment for Pseudomonas aeruginosa Wound Infections by Quorum-Sensing Inhibitors Mediated by Poly(amidoamine) (PAMAM) Dendrimers

  6. Indirect pathogenicity of Haemophilus influenzae and Moraxella catarrhalis in polymicrobial otitis media occurs via interspecies quorum signaling.

    Science.gov (United States)

    Armbruster, Chelsie E; Hong, Wenzhou; Pang, Bing; Weimer, Kristin E D; Juneau, Richard A; Turner, James; Swords, W Edward

    2010-07-06

    Otitis media (OM) is among the leading diseases of childhood and is caused by opportunists that reside within the nasopharynx, such as Haemophilus influenzae and Moraxella catarrhalis. As with most airway infections, it is now clear that OM infections involve multiple organisms. This study addresses the hypothesis that polymicrobial infection alters the course, severity, and/or treatability of OM disease. The results clearly show that coinfection with H. influenzae and M. catarrhalis promotes the increased resistance of biofilms to antibiotics and host clearance. Using H. influenzae mutants with known biofilm defects, these phenotypes were shown to relate to biofilm maturation and autoinducer-2 (AI-2) quorum signaling. In support of the latter mechanism, chemically synthesized AI-2 (dihydroxypentanedione [DPD]) promoted increased M. catarrhalis biofilm formation and resistance to antibiotics. In the chinchilla infection model of OM, polymicrobial infection promoted M. catarrhalis persistence beyond the levels seen in animals infected with M. catarrhalis alone. Notably, no such enhancement of M. catarrhalis persistence was observed in animals infected with M. catarrhalis and a quorum signaling-deficient H. influenzae luxS mutant strain. We thus conclude that H. influenzae promotes M. catarrhalis persistence within polymicrobial biofilms via interspecies quorum signaling. AI-2 may therefore represent an ideal target for disruption of chronic polymicrobial infections. Moreover, these results strongly imply that successful vaccination against the unencapsulated H. influenzae strains that cause airway infections may also significantly impact chronic M. catarrhalis disease by removing a reservoir of the AI-2 signal that promotes M. catarrhalis persistence within biofilm.

  7. Designer cells programming quorum-sensing interference with microbes.

    Science.gov (United States)

    Sedlmayer, Ferdinand; Hell, Dennis; Müller, Marius; Ausländer, David; Fussenegger, Martin

    2018-05-08

    Quorum sensing is a promising target for next-generation anti-infectives designed to address evolving bacterial drug resistance. The autoinducer-2 (AI-2) is a key quorum-sensing signal molecule which regulates bacterial group behaviors and is recognized by many Gram-negative and Gram-positive bacteria. Here we report a synthetic mammalian cell-based microbial-control device that detects microbial chemotactic formyl peptides through a formyl peptide sensor (FPS) and responds by releasing AI-2. The microbial-control device was designed by rewiring an artificial receptor-based signaling cascade to a modular biosynthetic AI-2 production platform. Mammalian cells equipped with the microbial-control gene circuit detect formyl peptides secreted from various microbes with high sensitivity and respond with robust AI-2 production, resulting in control of quorum sensing-related behavior of pathogenic Vibrio harveyi and attenuation of biofilm formation by the human pathogen Candida albicans. The ability to manipulate mixed microbial populations through fine-tuning of AI-2 levels may provide opportunities for future anti-infective strategies.

  8. Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analogue

    Directory of Open Access Journals (Sweden)

    Sigde Mamani

    2016-09-01

    Full Text Available While a functional quorum sensing system has been identified in the acidophilic chemolithoautotroph Acidithiobacillus ferrooxidans ATCC 23270T and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in At. ferrooxidansT, the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL analogue has been studied. First, the effect on biofilm formation of a synthetic AHL tetrazolic analogue, tetrazole 9c, known for its agonistic QS activity, was assessed by fluorescence and electron microscopy experiments. A faster adherence of At. ferrooxidansT cells on sulfur coupons was observed. Then, tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signalling, and more particularly, those involved in early biofilm formation. Interestingly, afeI gene, encoding the AHL synthase, but not the At. ferrooxidans quorum sensing transcriptional regulator AfeR encoding gene, was shown to be regulated by quorum sensing. Data indicated that QS network represents at least 4.5 % (141 genes of the ATCC 23270T genome of which 42.5 % (60 genes are related to biofilm formation. Finally, AfeR was shown to bind specifically to the regulatory region of the afeI gene at the level of the palindromic sequence predicted to be the AfeR binding site. Our results give new insights on the response of At. ferrooxidans to quorum sensing and on biofilm biogenesis, opening new biological/chemical alternatives for bioleaching development and managing acid Mine/Rock drainage environmental damages.

  9. Establishing bacterial communities by 'word of mouth': LuxS and autoinducer 2 in biofilm development.

    Science.gov (United States)

    Hardie, Kim Rachael; Heurlier, Karin

    2008-08-01

    Multicellular bacterial communities (biofilms) abound in nature, and their successful formation and survival is likely to require cell-cell communication--including quorum sensing--to co-ordinate appropriate gene expression. The only mode of quorum sensing that is shared by both Gram-positive and Gram-negative bacteria involves the production of the signalling molecule autoinducer 2 by LuxS. A survey of the current literature reveals that luxS contributes to biofilm development in some bacteria. However, inconsistencies prevent biofilm development being attributed to the production of AI2 in all cases.

  10. Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, P.O.; Burmolle, M.

    2005-01-01

    to otherwise lethal doses of antibiotics and are protected from bactericidal activity of polymorphonuclear leukocytes (PMNs). P. aeruginosa controls the expression of many of its virulence factors by means of a cell-cell communication system termed quorum sensing (QS). In the present report it is demonstrated...... that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms led...... to an immediate respiratory-burst activation of the PMNs in vitro. In vivo QS-deficient mutants provoked a higher degree of inflammation. It is suggested that quorum signals and QS-inhibitory drugs play direct and opposite roles in this process. Consequently, the faster and highly efficient clearance of QS-deficient...

  11. En rejse ind i dental biofilm

    DEFF Research Database (Denmark)

    Schlafer, Sebastian

    Som klinkassistent og tandplejer arbejder man hver dag med bakteriel biofilm på tandoverfladerne – plak. Alle ved udmærket, at denne biofilm er ansvarlig for mundhulens hyppigste sygdomme, caries og parodontitis. Vi renser patienternes tænder for biofilm og opfordrer dem til at fjerne biofilmen...... mindst to gange om dagen, så grundigt de kan. Desuden bruges der en lang række antibakterielle tilsætningsstoffer i både tandpasta og mundskyllevæsker, hvis hovedformål er at dræbe bakterierne i dental biofilm. Men er biofilmen virkelig kun farlig? Nyere forskning har vist, at mennesket faktisk i høj...... grad er afhængig af de bakterier, der koloniserer kroppen. Hvorfor gælder dette tilsyneladende ikke for mundhulen? I løbet af præsentationen vil jeg tage tilhørerne med på en rejse ind i dental biofilm. Jeg vil belyse den komplekse bakterielle arkitektur, som kendetegner biofilmen, og vil analysere de...

  12. Meningsskabelse og meningstab

    DEFF Research Database (Denmark)

    Olsén, Peter; Hagedorn-Rasmussen, Peter

    2008-01-01

    Meningsfulde forandringsprocesser i arbejdslivet kræver, at der skabes rum til at fokusere på både indhold og betingelser i arbejdet. At man mestrer arbejdet, og at arbejde og produkt har kvalitet og nytte, er omdrejningspunkt i en positiv oplevelse af arbejdet - og drivkraft i ny meningsskabelse...

  13. GI og GISc

    DEFF Research Database (Denmark)

    Brande-Lavridsen, Hanne

    Udviklingen inden for kort- og geodataverdenen ligner udviklingen inden for alle andre erhverv, hvor globaliseringen spiller en stor rolle. Her kan man vælge de negative tilgang og se udviklingen som uoverskuelig og foruroligende. Eller man kan vælge en positiv og se udviklingen som udfordrende og...

  14. Pigebilleder og drengestreger

    DEFF Research Database (Denmark)

    Nielsen, Anne Maj

    Med udgangspunkt i børns tegninger gøres der i bogen rede for børns billedsmæssige udvikling og billedsocialisation, for personlige, lokale og kulturelle betydninger i børns billeder i form af forskellige symbollag samt for ligheder og forskelle i piger og drenges billeder og billedsocialisation....

  15. Om musik og multimedier

    DEFF Research Database (Denmark)

    Knakkergaard, Martin

    1998-01-01

    Artiklen søger, gennem eksemplificering og diskussion, at problematisere forholdet musik og multimedia. Der er ikke tale om et forsøg på at nå til nogen endegyldig afgrænsning og bestemmelse af de karakteristika og betingelser, der kendetegner feltet. Formålet er derimod at belyse og præcisere...

  16. Urbanitet, lyd og kunst

    DEFF Research Database (Denmark)

    2012-01-01

    designere med lyd og kunst i byrummet? Med dette fokus ønsker vi at definere og diskutere fremkomsten nye relationer mellem byen og den auditive kultur, hvor stedsspecificitet, byens kvalitative og æstetiske lyde og det offentlige rums uforudsigelighed tages op. Vi har inviteret danske såvel som...

  17. Optimal census by quorum sensing

    Science.gov (United States)

    Taillefumier, Thibaud

    Bacteria regulate their gene expression in response to changes in local cell density in a process called quorum sensing. To synchronize their gene-expression programs, these bacteria need to glean as much information as possible about local density. Our study is the first to physically model the flow of information in a quorum-sensing microbial community, wherein the internal regulator of the individual's response tracks the external cell density via an endogenously generated shared signal. Combining information theory and Lagrangian optimization, we find that quorum-sensing systems can improve their information capabilities by tuning circuit feedbacks. At the population level, external feedback adjusts the dynamic range of the shared input to individuals' detection channels. At the individual level, internal feedback adjusts the regulator's response time to dynamically balance output noise reduction and signal tracking ability. Our analysis suggests that achieving information benefit via feedback requires dedicated systems to control gene expression noise, such as sRNA-based regulation.

  18. Dokumentation og forskning

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2013-01-01

    og psykologiske symptomer på demens. Endelig omtales udgivelsen af "Musical life stories. Narratives on health musicking" fra det norske Senter for Musikk og Helse, og Nordic Journal of Music Therapi beskrives som et toneangivende tidsskrift for international musikterapi....

  19. Teori og baggrundsviden

    DEFF Research Database (Denmark)

    Skytte, Marianne

    2005-01-01

    Bogdel med følgende kapitler: Statistik om befolkningssammensætningen i Danmark. Kultur og etnicitet. Kategorisering, stereotypering, stigmatisering og diskrimination. Integrationsstrategier. Værdier omkring familieliv og børneopdragelse. Tosprogethed. Kulturagram. Dilemmaet mellem ligebehandling...

  20. An update on Pseudomonas aeruginosa biofilm formation, tolerance, and dispersal

    DEFF Research Database (Denmark)

    Harmsen, Morten; Yang, Liang; Pamp, Sünje Johanna

    2010-01-01

    We review the recent advances in the understanding of the Pseudomonas aeruginosa biofilm lifestyle from studies using in vitro laboratory setups such as flow chambers and microtiter trays. Recent work sheds light on the role of nutrients, motility, and quorum sensing in structure formation in P....... aeruginosa biofilms. The second messenger, c-di-GMP, is established as an important regulator of the synthesis of polysaccharide and protein components of the biofilm matrix. Extracellular DNA is shown to be an essential component of the biofilm matrix. It has become apparent that biofilm formation involves...... interactions between different subpopulations. The molecular mechanisms underlying the tolerance of biofilm bacteria to antimicrobial agents are beginning to be unraveled, and new knowledge has been obtained regarding the environmental cues and regulatory mechanisms involved in biofilm dispersal....

  1. Bacterial signaling ecology and potential applications during aquatic biofilm construction.

    Science.gov (United States)

    Vega, Leticia M; Alvarez, Pedro J; McLean, Robert J C

    2014-07-01

    In their natural environment, bacteria and other microorganisms typically grow as surface-adherent biofilm communities. Cell signal processes, including quorum signaling, are now recognized as being intimately involved in the development and function of biofilms. In contrast to their planktonic (unattached) counterparts, bacteria within biofilms are notoriously resistant to many traditional antimicrobial agents and so represent a major challenge in industry and medicine. Although biofilms impact many human activities, they actually represent an ancient mode of bacterial growth as shown in the fossil record. Consequently, many aquatic organisms have evolved strategies involving signal manipulation to control or co-exist with biofilms. Here, we review the chemical ecology of biofilms and propose mechanisms whereby signal manipulation can be used to promote or control biofilms.

  2. PH og modernismen

    DEFF Research Database (Denmark)

    Ahnfeldt-Mollerup, Merete

    2012-01-01

    Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus.......Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus....

  3. Folkedans, elitekultur og nationalisme

    DEFF Research Database (Denmark)

    Østergaard, Uffe

    2017-01-01

    Historisk set. Begreberne folkedans og folkemusik blev i løbet af 1900-tallet overtaget af de udøvende, og samtidig ændredes dansens sociale funktion og rituelle betydning. Folkedansen er ikke blevet til et nationalt symbol.......Historisk set. Begreberne folkedans og folkemusik blev i løbet af 1900-tallet overtaget af de udøvende, og samtidig ændredes dansens sociale funktion og rituelle betydning. Folkedansen er ikke blevet til et nationalt symbol....

  4. Vision og virkelighed

    DEFF Research Database (Denmark)

    Carlsen, Benny Bang

    Bogen behandler andetsprogsdidaktiske problemstillinger og emner som fx sproglig opmærksomhed, kontrastiv lingvistik, kommunikativ kompetence, andetsprogstilegnelsesteorier, intersprogsanalyse og kulturmødet....

  5. Immaterialret og IT

    DEFF Research Database (Denmark)

    Riis, Thomas

    Indhold: Beskyttelse af edb-programmer ; Patentbeskyttelse af softwarerelaterede opfindelser ; Beskyttelse af databaser ; Ophavsret og internettet ; Beskyttelse af halvlederkredsløb ; Informationsteknologi og konkurrence...

  6. Synthetic furanones inhibit quorum-sensing and enhance bacterial clearance in Pseudomonas aeruginosa lung infection in mice

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.; Hentzer, Morten

    2004-01-01

    Introduction: Antibiotics are used to treat bacterial infections by killing the bacteria or inhibiting their growth, but resistance to antibiotics can develop readily. The discovery that bacterial quorum-sensing regulates bacterial virulence as well as the formation of biofilms opens up new ways...... to control certain bacterial infections. Furanone compounds capable of inhibiting bacterial quorum-sensing systems have been isolated from the marine macro alga Delisea pulchra. Objectives: Two synthetic furanones were tested for their ability to attenuate bacterial virulence in the mouse models of chronic...

  7. Antibiotic resistance in Pseudomonas aeruginosa biofilms: towards the development of novel anti-biofilm therapies.

    Science.gov (United States)

    Taylor, Patrick K; Yeung, Amy T Y; Hancock, Robert E W

    2014-12-10

    The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Combating biofilms

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Wu, Hong

    2012-01-01

    Biofilms are complex microbial communities consisting of microcolonies embedded in a matrix of self-produced polymer substances. Biofilm cells show much greater resistance to environmental challenges including antimicrobial agents than their free-living counterparts. The biofilm mode of life...... is believed to significantly contribute to successful microbial survival in hostile environments. Conventional treatment, disinfection and cleaning strategies do not proficiently deal with biofilm-related problems, such as persistent infections and contamination of food production facilities. In this review......, strategies to control biofilms are discussed, including those of inhibition of microbial attachment, interference of biofilm structure development and differentiation, killing of biofilm cells and induction of biofilm dispersion....

  9. Smagsoplevelse og Fordybelse

    DEFF Research Database (Denmark)

    Brodersen, Peter

    2017-01-01

    Smag og smagsoplevelser har en selvstændig plads i faget madkundskab, og som sådan er de sigtekorn for dannelsesforestillinger. Med afsæt i teorien om kategorial dannelse drøfter kapitlet, hvordan fordybelse gennem sansebaserede og æstetiske smagsoplevelser på den ene side og analytiske aktivitet...

  10. Dokumentation og forskning

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2018-01-01

    Nyt fra Forskerprogrammet i musikterapi. Review-artikler vedr. musikterapi og onkologi og demens. Særnummer i Approaches om Europæisk GIM forening. Bogudgivelse: Lindvang & Beck (Red). Musik, krop og følelser. Neuroaffektive processer i musikterapi samt Jensen (Red.) Kultur og Sundhed. TV-serie s...

  11. Emergens og transkulturalitet

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2009-01-01

    Artiklen handler om, hvordan latinamerikansk litteratur og især magisk realisme udveksler med verden og hvordan den læses og brandes uden for Latinamerika. Jeg argumenterer for, at begreberne "emergens" (Wlad Godzich) og "transkulturation" (Fernando Ortiz) er gode til at beskrive nogle af de...

  12. Inger og Johannes Exner

    DEFF Research Database (Denmark)

    Jensen, Thomas Bo

    Monografi om Inger og Johannes Exners arkitektur. Bogen behandler indgående Exners inspirationer samt deres teorier vedrørende kirkearkitektur og restaurering.......Monografi om Inger og Johannes Exners arkitektur. Bogen behandler indgående Exners inspirationer samt deres teorier vedrørende kirkearkitektur og restaurering....

  13. Xerostomi og nedsat spytsekretion

    DEFF Research Database (Denmark)

    Jensen, Siri Beier; Dynesen, Anja Weirsøe; Pedersen, Anne Marie Lynge

    2011-01-01

    Forekomst og årsager til xerostomi og nedsat spytsekretion ' Xerostomi er defineret som den subjektive følelse af mundtørhed og er som oftest en følge af nedsat eller manglende spytsekretion. Xerostomi kan dog også forekomme uden objektiv dysfunktion af spytkirtlerne. De grundlæggende årsager til...

  14. Lyset og livet

    DEFF Research Database (Denmark)

    Oxenvad, Carsten Michael

    2003-01-01

    Beskrivelse af Øster Aaby Friskole og friskoler generelt. Blandt bidragyderne: Susanne Eskildsen, Holger Henriksen, Margrethe Vestager, John Iversen, Thorstein Balle og Poul Erik Søe......Beskrivelse af Øster Aaby Friskole og friskoler generelt. Blandt bidragyderne: Susanne Eskildsen, Holger Henriksen, Margrethe Vestager, John Iversen, Thorstein Balle og Poul Erik Søe...

  15. Hund og menneske imellem

    DEFF Research Database (Denmark)

    Hovmark, Henrik

    2009-01-01

    og menneske imellem? Denne artikel beskriver hvordan hundelivet bliver udfoldet i Ordbog over det danske Sprog (ODS), Den Danske Ordbog (DDO) og Ømålsordbogen (ØMO). Fælles for ODS, DDO og ØMO er at de er videnskabeligt beskrivende ordbøger. Det betyder ideelt set at man indsamler og beskriver...

  16. Designprocesser og digital produktion:

    DEFF Research Database (Denmark)

    Pilgaard, Michal; Lembcke, Steen

    Der er fokus på Fab-Labs som ramme for en social læringskontekst i folkeskolen, hvor elever sammen med lærere og pædagoger får mulighed for at udforske teknologier og fremstille digitale produkter og produktioner. I læringsmiljøet hvor designprocessen og den digitale fabrikation udfoldes...

  17. Quickplace - anvendelse og muligheder

    DEFF Research Database (Denmark)

    Bojesen, Jakob Cloos

    beskrives status og fremtidsudsigter for brugen af systemet på Aalborg Universitet. De opnåede erfaringer med emner som mulige anvendelsesområder, organisatorisk forankring, support og tilretning af systemet beskrives, og rapporten kan således inspirere og informere andre, som står over for at vælge en...

  18. Formalsproglig kompetence og IT

    DEFF Research Database (Denmark)

    Ambjørn, Lone

    2002-01-01

    Sproglæringsteoretisk værktøj til udvikling af IT-støttede materialer og programmer inden for grammatisk og leksikalsk kompetence......Sproglæringsteoretisk værktøj til udvikling af IT-støttede materialer og programmer inden for grammatisk og leksikalsk kompetence...

  19. Mord og metafysik

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    Krimien er traditionelt indskrevet i en moderne samfundsramme, hvor opklaringen sker ved hjælp af rationelle og empiriske hjælpemidler. Derfor har krimien gennem mange år været kritisk over for metafysik, religion og det overnaturlige. Mord og metafysik viser, at skellet mellem krimi og metafysik...

  20. Supervisand og supervisor

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard

    2007-01-01

    Kapitlet redegør for aspekter ved det komplekse forhold mellem supervisand og supervisor, og der anlægges en række forskellige perspektiver. Først beskrives forholdet fra supervisandens perspektiv. At indtræde i rollen som supervisand er, foruden at være lærerigt og fagligt udviklende, ofte også ...

  1. Supervisionens materiale og proces

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard

    2007-01-01

    Kapitlet handler om supervisionens materiale og proces, dvs. spørgsmålene om, hvilket materiale supervisanden skal medbringe til supervision, hvordan det skal fremlægges, og hvordan valg af materiale og metode gensidigt indvirker på hinanden og på supervisionsprocessen. Som de mest anvendte metoder...

  2. Professionalitet og medlemsdemokrati

    DEFF Research Database (Denmark)

    Nielsen, Anette; Johannsen, Gundi Schrötter

    2017-01-01

    begreb om udspændthed (Kofoed 2003 & Neidel 2011) samt Erving Goffmans begreber om frontstage og backstage (Jacobsen & Kristiansen 2014). Analyserne viser en kompleks praksis udspændt mellem forskelligrettede krav og forventninger og med stadige forhandlinger, som både medarbejdere og medlemmer må...

  3. Kamp og status

    DEFF Research Database (Denmark)

    Hansen, Christian Sandbjerg; Dahl, Hanne Marlene; Eklund Hansen, Anette

    Dette bind er det første af to om børnehavens og pædagogprofessionens historie og aktualitet. Bind 2, Kald og kundskab, går tæt på indholdet i småbørnspædagogikken og i uddannelserne fra 1870 til i dag....

  4. Normalitet og afvigelse

    DEFF Research Database (Denmark)

    Holst, Jesper

    2009-01-01

    Anmeldelse ad Ivar Morkens bog:" Normalitet og afvigelse", der tager udgangspunkt i kontrasten mellem visionerne om inklusion, empowerment og anerkendelse og de faktiske forhold, hvor menneskelig afvig stadig diagnosticeres. Kontrasterne defineres og forsøges imødegået med forskellige former for ...

  5. Musik og folkesundhed

    DEFF Research Database (Denmark)

    Bonde, Lars Ole; Ekholm, Ola

    2015-01-01

    Præsentation af undersøgelsen "Musik og folkesundhed", som er blevet til i et samarbejde mellem Musikterapi AAU og Statens Institut for Folkesundhed......Præsentation af undersøgelsen "Musik og folkesundhed", som er blevet til i et samarbejde mellem Musikterapi AAU og Statens Institut for Folkesundhed...

  6. 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...

  7. Social innovation og aktionsforskning

    DEFF Research Database (Denmark)

    Andersen, John; Bilfeldt, Annette

    2014-01-01

    Formålet med dette kapitel er at vise, hvordan aktionsforskning kan bidrage til social innovation og empowerment i velfærds- og kulturinstitutioner (plejehjem og biblioteker) på en måde, der fremmer marginaliserede medborgere og lokalområders magtposition og skaber muligheder for positiv forandring....... Kapitlet præsenterer først mere overordnet de kritiske begreber om empowerment, aktionsforskning og social innovation og disse tilganges rødder i kritisk teori. Efterfølgende gennemgås to forskellige metodiske varianter af aktionsforskning i to forskellige kontekster....

  8. Medier og digital kultur

    DEFF Research Database (Denmark)

    Christiansen, René Boyer; Hestbech, Astrid Margrethe; Jørnø, Rasmus Leth Vergmann

    ser en film eller er til en koncert. Børn og unge bliver ikke længere betragtet som novicer, men mere som forbrugere og kunder, der kræver at blive engageret og underholdt. Også i pædagogisk praksis må man derfor tage højde for, at børn, unge og brugere generelt kommer med nye forventninger og...... målbeskrivelser og krav til metodevalget, og der findes nu et modul, der indholdsmæssigt fokuserer på netop medier og digital kultur. Der er derfor behov for et samlet værk, der fagligt funderet diskuterer den nyeste viden om medier i pædagogisk praksis ud fra kravene om fokuseret og reflekteret arbejde med mål...

  9. Flow og fordybelse

    DEFF Research Database (Denmark)

    Andersen, Frans Ørsted

    2010-01-01

    Artiklen handler om flow og fordybelse i et nyt tværfagligt / naturfagligt undervisningskoncept, "Overvågningens dilemma", til brug i folkeskolens 7.-9.kl. og på gymnasiale uddannelser. Konceptet sætter fokus på den overvågning der foregår og er mulig i nutidens IT og hi-tec samfund og der arbejd...

  10. Kulturel og mental byomdannelse

    DEFF Research Database (Denmark)

    Samson, Kristine

    2013-01-01

    Redesign og kulturel byomdannelse kan være tankevækkende studier af, hvordan byer udvikler sig og omdannes under indflydelse af sociale, kulturelle og økonomiske sammenhænge. Parque Cultural de Valparaiso i Chile er et fremragende eksempel på, hvordan arkitektur og landskabsdesign forbinder sig til...... den omkringliggende by og Chiles komplekse historie. Men Parque Cultural giver samtidig et arkitektonisk rumligt bud på Valparaiso mulige fremtid....

  11. Farestrategier og trampolinleg

    DEFF Research Database (Denmark)

    Karoff, Helle Skovbjerg

    Vild og farlig leg på havetrampoliner udfordrer børns sikkerhed og tryghed og er samtidig både udviklende og udfordrende. Børn kan lære at håndtere risici, når de leger på trampolinen. Helle Skovbjerg Karoff er adjunkt ved Aalborg Universitet/København og knyttet til forskningslaboratoriet for IT...

  12. Quorum quenching bacteria can be used to inhibit the biofouling of reverse osmosis membranes.

    Science.gov (United States)

    Oh, Hyun-Suk; Tan, Chuan Hao; Low, Jiun Hui; Rzechowicz, Miles; Siddiqui, Muhammad Faisal; Winters, Harvey; Kjelleberg, Staffan; Fane, Anthony G; Rice, Scott A

    2017-04-01

    Over the last few decades, significant efforts have concentrated on mitigating biofouling in reverse osmosis (RO) systems, with a focus on non-toxic and sustainable strategies. Here, we explored the potential of applying quorum quenching (QQ) bacteria to control biofouling in a laboratory-scale RO system. For these experiments, Pantoea stewartii was used as a model biofilm forming organism because it was previously shown to be a relevant wastewater isolate that also forms biofilms in a quorum sensing (QS) dependent fashion. A recombinant Escherichia coli strain, which can produce a QQ enzyme, was first tested in batch biofilm assays and significantly reduced biofilm formation by P. stewartii. Subsequently, RO membranes were fouled with P. stewartii and the QQ bacterium was introduced into the RO system using two different strategies, direct injection and immobilization within a cartridge microfilter. When the QQ bacterial cells were directly injected into the system, N-acylhomoserine lactone signals were degraded, resulting in the reduction of biofouling. Similarly, the QQ bacteria controlled biofouling when immobilized within a microfilter placed downstream of the RO module to remove QS signals circulating in the system. These results demonstrate the proof-of-principle that QQ can be applied to control biofouling of RO membranes and may be applicable for use in full-scale plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1

    Directory of Open Access Journals (Sweden)

    Huiming Tang

    2018-03-01

    Full Text Available Quorum sensing (QS regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ, the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT and ΔrhlR strains are significantly higher than those in the ΔlasR strain. Supplementation of ΔlasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa. This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  14. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Tang, Huiming; Zhang, Yunyun; Ma, Yifan; Tang, Mengmeng; Shen, Dongsheng; Wang, Meizhen

    2018-01-01

    Quorum sensing (QS) regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ), the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT) expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT) and Δ rhlR strains are significantly higher than those in the Δ lasR strain. Supplementation of Δ lasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa . This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  15. Development of Quorum-Based Anti-Virulence Therapeutics Targeting Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

    Full Text Available Quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. Lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. The quorum quenching therapeutic approach promises a lower risk of resistance development, since interference with virulence generally does not affect the growth and fitness of the bacteria and, hence, does not exert an associated selection pressure for drug-resistant strains. With better understanding of bacterial communication networks and mechanisms, many quorum quenching methods have been developed against various clinically significant bacterial pathogens. In particular, Gram-negative bacteria are an important group of pathogens, because, collectively, they are responsible for the majority of hospital-acquired infections. Here, we discuss the current understanding of existing quorum sensing mechanisms and present important inhibitory strategies that have been developed against this group of pathogenic bacteria.

  16. Et Forsknings- og Udviklingsprojekt om Marjattas Skole- og Behandlingshjem

    DEFF Research Database (Denmark)

    Kristensen, Kasper Andreas

    2011-01-01

    Forskning og udviklingsrapport om rytmer og kunstneriske processer i Marjattas Rudolf Steiner inspirerede specialpædagogik......Forskning og udviklingsrapport om rytmer og kunstneriske processer i Marjattas Rudolf Steiner inspirerede specialpædagogik...

  17. Prediction by promoter logic in bacterial quorum sensing.

    Directory of Open Access Journals (Sweden)

    Navneet Rai

    2012-01-01

    Full Text Available Quorum-sensing systems mediate chemical communication between bacterial cells, coordinating cell-density-dependent processes like biofilm formation and virulence-factor expression. In the proteobacterial LuxI/LuxR quorum sensing paradigm, a signaling molecule generated by an enzyme (LuxI diffuses between cells and allosterically stimulates a transcriptional regulator (LuxR to activate its cognate promoter (pR. By expressing either LuxI or LuxR in positive feedback from pR, these versatile systems can generate smooth (monostable or abrupt (bistable density-dependent responses to suit the ecological context. Here we combine theory and experiment to demonstrate that the promoter logic of pR - its measured activity as a function of LuxI and LuxR levels - contains all the biochemical information required to quantitatively predict the responses of such feedback loops. The interplay of promoter logic with feedback topology underlies the versatility of the LuxI/LuxR paradigm: LuxR and LuxI positive-feedback systems show dramatically different responses, while a dual positive/negative-feedback system displays synchronized oscillations. These results highlight the dual utility of promoter logic: to probe microscopic parameters and predict macroscopic phenotype.

  18. Identification of Pathways Critical to Quorum Sensing and Virulence Induction

    Energy Technology Data Exchange (ETDEWEB)

    Ognibene, Ted J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Young, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Holtz-Morris, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Daley, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2009-02-27

    Quorum sensing is a mode of intercellular communication between bacteria that allows them to collectively regulate behavior such as virulence, sporulation, motility and biofilm formation. It is mediated by bacterially synthesized, diffusible, signaling molecules (autoinducers) that increase in concentration as a bacterial population expands until a critical threshold concentration is reached. However, in most bacterial species that produce autoinducer molecules, the physiologic concentration of these molecules is unknown. Moreover, many bacterial species, including Y. pestis, produce an array of quorum sensing molecules and the physiologic concentration of each individual type of autoinducer molecule is not known. There is a need to accurately and precisely quantitate these molecules, as it may be that different types of autoinducer molecules have different effects on virulence in the bacterium. We focused our efforts on the construction of a platform to identify and quantitate autoinducer molecules using FTICR, 14C isotope labeling and accelerator mass spectrometry (AMS). Specifically, we focused on autoinducer-1 type molecules, acylhomoserine lactone (HSL), derived from S-adenosylmethionine (SAM).

  19. Proteomics of the bacterial cross-talk by quorum sensing.

    Science.gov (United States)

    Di Cagno, Raffaella; De Angelis, Maria; Calasso, Maria; Gobbetti, Marco

    2011-01-01

    Words such as language and behavior are frequently used to depict "quorum sensing" (QS) in the literature. Simplifying the concept, language and cross-talk between bacteria, and between bacteria and animal or plants hosts determine the behavior (e.g., beneficial or pathogenic effects). Genomics and transcriptomics were the principal approaches used to study the multiple mechanisms of QS. Nevertheless, sequencing of genomes paved the way for another approach which consists on comparative and functional proteomics. This review aims at describing how the proteomic dictionary translates: (i) the languages (N-acyl-L-homoserine lactones, AHL; autoinducing peptide, AIP; autoinducer-2, AI-2) used by bacteria to communicate; (ii) signals of QS which induce various phenotypes (e.g., virulence, biofilm maturation); (iii) cross-talk between lactic acid bacteria within various food ecosystems (e.g. sourdough and fermented milk); (iv) probiotic messages at intra- and inter-species and interkingdom levels; and (v) words for quorum quenching (QQ). Proteomics is an indispensible discipline to elucidate the mechanisms of regulation of the multitude of language signals which diffuse through different microbial communities. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Qualitative and quantitative determination of quorum sensing inhibition in vitro

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; van Gennip, Maria; Christensen, Louise Dahl

    2011-01-01

    of reporter strains consisting of a lasB-gfp or rhlA-gfp fusion in P. aeruginosa for qualitative and quantitative evaluation of the inhibition of the two major QS pathways, monitored as reduced expression of green fluorescence. By the use of an in vitro flow cell system it is possible to study the QSI...... efficacy of potential quorum sensing inhibitors (QSIs). Work on Pseudomonas aeruginosa has shown that chemical blockage of QS is a promising new antimicrobial strategy. Several live bacterial reporter systems been developed to screen extracts and pure compounds for QSI activity. Here we describe the usage...... activity by monitoring its ability to interfere with the protective functions of bacterial biofilm. For evaluation of the global effects of QSI compounds, we present a protocol for the DNA microarray-based transcriptomics. Using these in vitro methods it is possible to evaluate the potential of various QSI...

  1. From deep-sea volcanoes to human pathogens: a conserved quorum-sensing signal in Epsilonproteobacteria.

    Science.gov (United States)

    Pérez-Rodríguez, Ileana; Bolognini, Marie; Ricci, Jessica; Bini, Elisabetta; Vetriani, Costantino

    2015-05-01

    Chemosynthetic Epsilonproteobacteria from deep-sea hydrothermal vents colonize substrates exposed to steep thermal and redox gradients. In many bacteria, substrate attachment, biofilm formation, expression of virulence genes and host colonization are partly controlled via a cell density-dependent mechanism involving signal molecules, known as quorum sensing. Within the Epsilonproteobacteria, quorum sensing has been investigated only in human pathogens that use the luxS/autoinducer-2 (AI-2) mechanism to control the expression of some of these functions. In this study we showed that luxS is conserved in Epsilonproteobacteria and that pathogenic and mesophilic members of this class inherited this gene from a thermophilic ancestor. Furthermore, we provide evidence that the luxS gene is expressed--and a quorum-sensing signal is produced--during growth of Sulfurovum lithotrophicum and Caminibacter mediatlanticus, two Epsilonproteobacteria from deep-sea hydrothermal vents. Finally, we detected luxS transcripts in Epsilonproteobacteria-dominated biofilm communities collected from deep-sea hydrothermal vents. Taken together, our findings indicate that the epsiloproteobacterial lineage of the LuxS enzyme originated in high-temperature geothermal environments and that, in vent Epsilonproteobacteria, luxS expression is linked to the production of AI-2 signals, which are likely produced in situ at deep-sea vents. We conclude that the luxS gene is part of the ancestral epsilonproteobacterial genome and represents an evolutionary link that connects thermophiles to human pathogens.

  2. Food as a Source for Quorum Sensing Inhibitors: Iberin from Horseradish Revealed as a Quorum Sensing Inhibitor of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Bragason, Steinn Kristinn; Phipps, Richard Kerry

    2012-01-01

    of traditional antibiotics to treat infections caused by bacterial biofilms and multidrug-resistant bacteria. Several QSIs of natural origin have been identified, and in this study, several common food products and plants were extracted and screened for QSI activity in an attempt to isolate and characterize...... to transcend problems with selective pressures for antibiotic resistance, is to interrupt bacterial communication, also known as quorum sensing (QS), by means of signal antagonists, the so-called QS inhibitors (QSIs). Furthermore, QSI agents offer a potential solution to the deficiencies associated with use......-diode array detector-mass spectrometry (LC-DAD-MS) and nuclear magnetic resonance (NMR) spectroscopy as iberin—an isothiocyanate produced by many members of the Brassicaceae family. Real-time PCR (RT-PCR) and DNA microarray studies showed that iberin specifically blocks expression of QS-regulated genes in P...

  3. Heterogeneity of biofilms formed by nonmucoid Pseudomonas aeruginosa isolates from patients with cystic fibrosis

    DEFF Research Database (Denmark)

    Lee, Baoleri; Haagensen, Janus Anders Juul; Ciofu, O.

    2005-01-01

    lactone quorum-sensing molecules). Compared with wild-type strain PAO 1, most P. aeruginosa isolates demonstrated different degrees of reduction of adherence on polystyrene surfaces. The in vitro biofilm formation of isolates was investigated in a hydrodynamic flow system. Confocal laser scanning...... to phenotypic changes and in vitro biofilm formation. The physiological alterations were associated with a loss of motility (35% were nonmotile) and with decreased production of virulence factors (pyocyanin, proteases) and quorum-sensing molecules (45% of the isolates were unable to produce 3-O-C(12)-homoserine...

  4. Lydighedsetik og bureaukratisk grusomhed

    DEFF Research Database (Denmark)

    Moesby-Jensen, Cecilie Kolonda; Moesby-Jensen, Tommy

    2017-01-01

    I dette kapitel fokuseres der på samarbejdet mellem socialrådgivere i en forvaltnings familieafdeling og ansatte i Psykologisk og Pædagogisk Rådgivning (PPR). Vi vil vise, hvordan denne arbejdsorganisering har afgørende bureaukratiske træk og derfor rummer lydighedsetiske problemer – et begreb, d...... tager udgangspunkt i et myndighedssocialrådgiver-perspektiv og dermed i, hvordan de oplever samarbejdet. Analyserne fremskrives og diskuteres med udgangspunkt i teoretiske perspektiver hos Max Weber, Zygmunt Bauman, Etienne Wenger, Paul Duguid og John Seely Brown....

  5. Praksisteori og arbejdslivsforskning

    DEFF Research Database (Denmark)

    Buch, Anders

    2017-01-01

    Praksisteori er en lang og bred human- og socialvidenskabelig tradition, der forsøger at forstå mennesker, arbejde og samfund med udgangspunkt i aktivitet og handling. I denne artikel gøres der rede for praksisteoriens grundlæggende antagelser og begreber. Artiklen fokuserer på, hvordan nyere...... praksisteori – her Theodore Schatzkis teori om socialt liv – udvikler begreber til at forstå, hvordan det sociale liv er organiseret igennem praksisser, og hvordan normativitet i praksisser bidrager til at bestemme handlinger. Der argumenteres for, at den praksisteoretiske tilgang kan tilbyde...

  6. Individualiseringens vindere og tabere

    DEFF Research Database (Denmark)

    Rasborg, Klaus

    2013-01-01

    Snarere end værdiforfald og egoisme er nutidens individualisering ensbetydende med fremkomsten af nye værdier, deltagelsesformer og politiske orienteringsmønstre. Der er imidlertid både vindere og tabere i individualiseringsspillet, hvilket artiklen forsøger at vise.......Snarere end værdiforfald og egoisme er nutidens individualisering ensbetydende med fremkomsten af nye værdier, deltagelsesformer og politiske orienteringsmønstre. Der er imidlertid både vindere og tabere i individualiseringsspillet, hvilket artiklen forsøger at vise....

  7. Indre spenninger og ytre press

    DEFF Research Database (Denmark)

    Ibsen, Bjarne

    2011-01-01

    Anmeldelse af bogen 'Norsk idrett. Indre spenninger og ytre press' redigeret af Dag Vidar Hanstad, Gunnar Breivik, Mari Kristin Sisjord og Hans B. Skaset og udgivet af forlaet akilles.......Anmeldelse af bogen 'Norsk idrett. Indre spenninger og ytre press' redigeret af Dag Vidar Hanstad, Gunnar Breivik, Mari Kristin Sisjord og Hans B. Skaset og udgivet af forlaet akilles....

  8. Teamarbejde og samspillet mellem medarbejdere og organisation

    DEFF Research Database (Denmark)

    Jeppesen, Hans Jeppe; Jønsson, Thomas

    2008-01-01

    Gennem det seneste årti har brug af teams som en måde at organisere arbejdet på været i hastig fremmarch. Det er baggrunden for forskningsprojektet ”Team-organiseringens betydning for participation og organisatoriske relationer”, der er et multiple case-studie af seks organisationers brug af...... teamwork. Bag projektet står professor Hans Jeppe Jeppesen, cand.psych. og ph.d. Thomas Rasmussen samt adjunkt Thomas Jønsson. I denne klumme gives en forskningsbaseret introduktion til teamarbejdet og dets betydning for samspillet mellem medarbejdere og organisation. Med udgangspunkt i egen forskning...

  9. Humanisme, sprogvidenskab og matematik

    DEFF Research Database (Denmark)

    Prebensen, Henrik

    1999-01-01

    Kulturkløft, C.P.Snow, matematikkens grundlag, logik og sprog, strukturalisme, semantik, syntaks, Chomsky-kritik......Kulturkløft, C.P.Snow, matematikkens grundlag, logik og sprog, strukturalisme, semantik, syntaks, Chomsky-kritik...

  10. Sekularisering og religion

    DEFF Research Database (Denmark)

    Andersen, Kirsten Margrethe

    2015-01-01

    Sammendrag: Sekularisering og religion: En studie i fortællingens nøglerolle i folkeskolens religionsundervisning Kirsten M. Andersen Ph.d. afhandling, indleveret ved institut for Uddannelse og Pædagogik, Aarhus Universitet, d. 23. oktober 2014 Indledning Afhandlingens sigte er at bidrage til en...... fortsat udvikling af religionsundervisningen i skolen ud fra en almen pædagogisk interesse. Skolen har sit eget formål og derfor må religion ombrydes, så den gøres pædagogisk. Religionshistorisk, religionssociologisk og antropologisk opfattes religion og kultur i et kontinuum. Det betyder, at religion...... fænomenologiske overvejelser over, hvorfor filosofien har behov for at formulere en religionshermeneutik med henblik på en almen pædagogisk begrundelse for skolens religionsundervisning. I Del: Kap. 2: Afhandlingen indledes med at indkredse og definere både religion og sekularisering som kulturelle og kollektive...

  11. Krig, magt og kristendom

    DEFF Research Database (Denmark)

    Andersen, Svend

    2012-01-01

    Der gøres rede for Martin Luthers opfattelse af krig og soldateretik. Relevansen for nutiden antydes......Der gøres rede for Martin Luthers opfattelse af krig og soldateretik. Relevansen for nutiden antydes...

  12. Banalitet og egensind

    DEFF Research Database (Denmark)

    Tanderup, Sara

    2009-01-01

    Anmeldelse af Hannah Arendts Eichann i Jerusalem og Hans Magnus Enzensbergers Hamerstein eller egensindigheden......Anmeldelse af Hannah Arendts Eichann i Jerusalem og Hans Magnus Enzensbergers Hamerstein eller egensindigheden...

  13. Universitetsforskere, ledelse og styringslogik

    DEFF Research Database (Denmark)

    Nielsen, Thomas; Ingemann, Jan Holm

     Dette paper indeholder en erfaringsbaseret del og en teoretisk. Den erfaringsbaserede beskriver forfatternes oplevelser som institutledere under universiteternes transformationsproces fra kollegialt selvstyre med mål-ramme styring under relativ autonomi til professionelt ledet og topstyret...

  14. Biofilms in Infections of the Eye

    Directory of Open Access Journals (Sweden)

    Paulo J. M. Bispo

    2015-03-01

    Full Text Available The ability to form biofilms in a variety of environments is a common trait of bacteria, and may represent one of the earliest defenses against predation. Biofilms are multicellular communities usually held together by a polymeric matrix, ranging from capsular material to cell lysate. In a structure that imposes diffusion limits, environmental microgradients arise to which individual bacteria adapt their physiologies, resulting in the gamut of physiological diversity. Additionally, the proximity of cells within the biofilm creates the opportunity for coordinated behaviors through cell–cell communication using diffusible signals, the most well documented being quorum sensing. Biofilms form on abiotic or biotic surfaces, and because of that are associated with a large proportion of human infections. Biofilm formation imposes a limitation on the uses and design of ocular devices, such as intraocular lenses, posterior contact lenses, scleral buckles, conjunctival plugs, lacrimal intubation devices and orbital implants. In the absence of abiotic materials, biofilms have been observed on the capsule, and in the corneal stroma. As the evidence for the involvement of microbial biofilms in many ocular infections has become compelling, developing new strategies to prevent their formation or to eradicate them at the site of infection, has become a priority.

  15. Dokumentation og forskning

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2012-01-01

    Udover en liste over de nyeste specialeafhandlinger er der Nyt fra Forskerprogrammet i musikterapi, og bl.a. omtale af effekt-undersøgelser vedr. musik og autisme, immunsystemet samt astma.......Udover en liste over de nyeste specialeafhandlinger er der Nyt fra Forskerprogrammet i musikterapi, og bl.a. omtale af effekt-undersøgelser vedr. musik og autisme, immunsystemet samt astma....

  16. EPR, kvantemekanik og Bohr

    OpenAIRE

    Nielsen, Morten Klockmann

    2007-01-01

    Dette projekt omhandler området hvor filosofi og fysik smelter sammen. Kvantemekanikkens tilblivelse fik en hård medfart hvilket diskussionerne mellem især Albert Einstein og Niels Bohr vidner om. De var hovedpersoner i striden om hvordan kvantemekanikken skulle fortolkes, og diskussionen kulminerede i 1935 hvor Einstein sammen med kollegerne Podolsky og Rosen offentliggjorde en artikel med titlen “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?” (EPR-artiklen)....

  17. Uddannelse og Entrepreneurship

    DEFF Research Database (Denmark)

    Blenker, Per; Dreisler, Poul; Færgemann, Helle Maibom

    2004-01-01

    Innovation og entrepreneurship står højt på den politiske dagsorden og universiteterne er tiltænkt en central rolle i denne proces, hvis mål er at skabe større vækst og øget velfærd i samfundet. Et af midlerne har været at motivere til større samarbejde om forskning og uddannelse i samspil mellem...

  18. Mellem medicin og moral

    DEFF Research Database (Denmark)

    Eriksen, Sidsel

    2002-01-01

    Den dødsdømte Peder Worms sidste tid før skafottet i 1830'ernes København set ud en medicinsk synsvinkel repræsteret ved fængselslægen og frenologen (kraniesamleren) Carl Otto og en teologisk synsvinkel set ud fra fængselslægen og rationalisten C.F. Visbye og dennes samtaler med fangen....

  19. Innovation og digitalisering

    DEFF Research Database (Denmark)

    Ivang, Reimer

    2012-01-01

    Kapitet fokuserer på, hvordan og hvorfor den digitale teknologi og innovation er to sider af samme sag. Den digitale teknologi er af mange anerkendt som en af nutidens største forandringskræfter. Perez (2002) benævner det ligefrem en teknologisk revolution og sammenligner den digitale teknologi m......, at innovationsprocesser ofte vil være det bedste perspektiv til at forstå, identificere og realisere det virkelige potentiale i digitalisering....

  20. Stemmeret og straf

    DEFF Research Database (Denmark)

    Rytter, Jens Elo

    2016-01-01

    En analyse af hvorvidt det vil være foreneligt med Grl § 29 og med EMRK at fratage straffede personer stemmeret. Det overvejes også, hvilke grunde, der taler for hhv. imod at fratage straffede personer stemmeret......En analyse af hvorvidt det vil være foreneligt med Grl § 29 og med EMRK at fratage straffede personer stemmeret. Det overvejes også, hvilke grunde, der taler for hhv. imod at fratage straffede personer stemmeret...

  1. Kildebankemne: Slaveriet og Vestindien

    DEFF Research Database (Denmark)

    Sørensen, Christina Louise; Poulsen, Jens Aage; Peters, Rikke Louise Alberg

    2017-01-01

    Den digitale kildebank består af flere end 130 kilder, der er inddelt i de 12 temaer. I hvert tema stilledes der mellem 10-15 kilder til rådighed om slavehandelen, slavernes liv og arbejde på De Dansk Vestindiske Øer og meget mere. Til læremidlet er også udviklet lærervejledninger, opgaver og tri...

  2. Transfer og effekt

    DEFF Research Database (Denmark)

    Sørensen, Peter

    2017-01-01

    Effekt, virkning eller udbytte af en lederuddannelse afhænger af en række individuelle, uddannelsesmæssige og organisatoriske faktorer. Det ved vi fra uddannelsesforskningen og særligt fra forskningen i transfer. Kun hvis uddannelsesinstitutionerne såvel som de studerende og arbejdspladserne vil...... medvirke aktivt til at skabe og fremme transfer, kan man gøre sig forhåbninger om, at få effekt af en lederuddannelse....

  3. Landskabskaraktermetoden og kommunerne

    DEFF Research Database (Denmark)

    Caspersen, Ole H.; Føns, Christina; Ginsbak, Anette

    2010-01-01

    Seks sydjyske kommuner, By- og Landskabsstyrelsen, KL samt Skov & Landskab har i 2010 gennemført et projekt med henblik på videre udvikling og tilpasning af landskabskaraktermetoden. Målet var at tilpasse metoden til kommunernes behov og at gøre den mere operationel og overskuelig. Dette videnbla...... er det første af fire, der redegør for resultaterne fra projektet....

  4. Microbial Biofilm as a Smart Material

    Directory of Open Access Journals (Sweden)

    Christian Garde

    2015-02-01

    Full Text Available Microbial biofilm colonies will in many cases form a smart material capable of responding to external threats dependent on their size and internal state. The microbial community accordingly switches between passive, protective, or attack modes of action. In order to decide which strategy to employ, it is essential for the biofilm community to be able to sense its own size. The sensor designed to perform this task is termed a quorum sensor, since it only permits collective behaviour once a sufficiently large assembly of microbes have been established. The generic quorum sensor construct involves two genes, one coding for the production of a diffusible signal molecule and one coding for a regulator protein dedicated to sensing the signal molecules. A positive feedback in the signal molecule production sets a well-defined condition for switching into the collective mode. The activation of the regulator involves a slow dimerization, which allows low-pass filtering of the activation of the collective mode. Here, we review and combine the model components that form the basic quorum sensor in a number of Gram-negative bacteria, e.g., Pseudomonas aeruginosa.

  5. "Brugerens arme og ben"

    DEFF Research Database (Denmark)

    Munk-Madsen, Eva

    Omsorgspraksis, det praktiske, sociale og emotionelle arbejde omsorgsydere udfører i samspil med omsorgsmodtagere, har både diskursive og ikke-diskursive elementer. Disse er imidlertid tæt forbundne via arbejdets mellem-menneskelige karakter. I dette paper er det samspillet mellem diskurs og plej...

  6. Brugerens arme og ben

    DEFF Research Database (Denmark)

    Munk-Madsen, Eva

    2006-01-01

    Omsorgsarbejde, det praktiske, sociale og emotionelle arbejde omsorgsarbejdere udfører i samspil med omsorgsmodtagere, har både diskursive og praktiske elementer. Disse er tæt forbundne via arbejdets mellemmenneskelige karakter. I denne artikel er det samspillet mellem diskurs og plejepraksis i h...

  7. Samtidskunst og migration

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2010-01-01

    "Samtidskunst og migration. En oversigt over faglitteraturen" er en forskningsoversigt der gør status over hvad der hidtil er skrevet inden for det kunsthistoriske område om vor tids billedkunst og migration som politisk, socialt og kulturelt fænomen, primært i forbindelse med immigration til...

  8. Ledelsesfilosofi og Praksis

    DEFF Research Database (Denmark)

    Hertel, Frederik; Fast, Michael

    2015-01-01

    , som f.eks. Machiavellis ”Fyrsten”, Platons ”Statsmanden”, Taylors ”The Principles of Scientific Management” og Fayols ”General and Industrial Management”, har ledelse og ledelsesforskningen således koncentreret sig om ledelsestyper, god/rigtig ledelse, management/organisering og arbejdsdeling...

  9. Reminiscens, livshistorie og demensomsorg

    DEFF Research Database (Denmark)

    Jensen, Anders Møller

    2015-01-01

    Reminiscens har vundet indpas i plejen af og omsorgen for mennesker med demens. Der er flere udlægninger af, hvordan reminiscens skal defineres, og det har betydet, at implementeringen har antaget mange former. Det gør det vanskeligt at sammenligne studier på området. Forskning og klinisk praksis...

  10. Mellem kommunikation og kreativitet

    DEFF Research Database (Denmark)

    Eriksson, Birgit

    2014-01-01

    Den franske filosof og kunstteoretiker Yves Michaud har argumenteret for, at moderniteten er karakteriseret ved tre utopier: Utopien om demokratisk medborgerskab, arbejdets utopi og kunstens utopi. Kunstens utopi sporer han tilbage til Immanuel Kants æstetik og hans forestilling om, at vi i...

  11. Etnologien og industrisamfundets kulturarv

    DEFF Research Database (Denmark)

    Højrup, Thomas

    2007-01-01

    Kulturarven anskues her som den praksis vi står på skuldrene af, og som vi bygger på, når vi skal tage stilling til, hvordan vi griber dagens aktuelle problemstillinger an. Med dette udgangspunkt diskuteres de begreber og opfattelser af "industrisamfundet", vi har fået i arv og må tage stilling t...

  12. Person og Rolle

    DEFF Research Database (Denmark)

    Szatkowski, Janek

    2011-01-01

    Distinktionen mellem person og rolle forslås som grundlag for et præcist og anlytisk anvendeligt begreb om performativitet. Begrebet tager sigte på at beskrive enkeltindividers og gruppers kommunikation med henblik på hvordan kommunikation etableres. Performativitet gør det muligt at iagttage den...

  13. Skolehaver, maddannelse og naturformidling

    DEFF Research Database (Denmark)

    Wistoft, Karen

    2011-01-01

    sundhedsfremmende effekter, der gør, at elevernes faglige, alsidige og sociale kompetencer bliver styrket. Sammenlignes Haver til Maver med andre skolehaveprojekter rundt omkring i verden, adskiller dette koncept sig ved det centrale fokus på gastronomi og urkræfter. Treenigheden mellem haver, udekøkken og den...

  14. Unges liv og muligheder

    DEFF Research Database (Denmark)

    Berliner, Peter; Fanous, Sandrine; Wattar, Laila

    2010-01-01

    trivsel og deltagelse kan øges. De unge deltog i fokusgruppeinterviews, individuelle interviews, udfyldelse af et spørgeskema, arrangering af et borgermøde samt i overvejelser omkring undersøgelsens metode og design og analysen af data. Analysen af data pegede på en række vigtige betingelser for at øge de...

  15. Midlertidighedens paradokser og rationaler

    DEFF Research Database (Denmark)

    Kiib, Hans

    2016-01-01

    metoder, der har til formål at fremme en social bevidsthed om at tingene kunne være anderledes og styrke et lokalt beredskab i forhold at kunne handle herpå. I dag oplever vi, at disse metoder i stadig stigende omfang operationaliseres og implementeres i planlægningen i kommuner og hos private investorer...

  16. Institution, profession og samfund

    DEFF Research Database (Denmark)

    Olesen, Henning Salling; Warring, Niels; Nielsen, Steen Baagøe

    2014-01-01

    Artiklen introducerer en sociologisk forståelse af institutioner som både et konkret sted og en samfundsmæssig byggesten. De pædagogiske institutioners udvikling med samfundsmæssige transformationer danner rammen om en historisk og funktionel beskrivelse af det pædagogiske arbejde, og det spændin...

  17. Prekarisering og akademisk arbejde

    DEFF Research Database (Denmark)

    Gleerup, Janne; Nielsen, Birger Steen; Olsén, Peter

    2018-01-01

    Artiklen fremlægger resultater fra et forskningsprojekt, der handler om de subjektive sider af prekarisering. Den empiriske del fokuserer på en udvalgt gruppe af akademikere, der er ramt af prekarisering på det danske arbejdsmarked, og hvordan de oplever og lever med midlertidige og usikre arbejd...

  18. Internationalisering og sprogpolitik

    DEFF Research Database (Denmark)

    Rasmussen, Palle

    2008-01-01

    Internationaliseringen af uddannelse og erhverv sker helt overvejende via det engelske sprog, som kommer til at dominere mere og mere. Som modvægt hertil er det vigtigt at danske forskere og universiteter gør en bevidst indsats for at opretholde dansk som videnskabssprog. Derimod er det mere prob...

  19. Mellem 'arkitekturen' og kroppen

    DEFF Research Database (Denmark)

    Peters, Terri

    2009-01-01

    I forbindelse med det internationale klimatopmøde COP15 i København har Kunstakademiets Arkitektskoles Institut for Teknologi og Institut for Planlægning i samarbejde med arkitekten Philippe Rahm, forskere og studerende sat fokus på arkitekturens rolle i klimadebatten. Udstillingen Klima og...

  20. Potentialitet og optimering

    DEFF Research Database (Denmark)

    Hamre, Bjørn

    . Afhandlingen kan både ses som et bidrag til eksisterende governmentality studier inden for uddannelse og som et bidrag til forskning i specialpædagogik. Optimering ses som en type rationalitetsform og magtudøvelse, der defi nerer problemforståelser i nutiden og sætter et skel mellem den adfærd, der inkluderes...

  1. Overskydende og fremmede byrum

    DEFF Research Database (Denmark)

    Nielsen, Tom

    2008-01-01

    Hvordan kan vi overhoved forstå og sammenkæde begreber som 'byrum', 'udviklingsstrategi' og temaet 'det fremmede i det kendte'? I det efterfølgende vil jeg give et bud på dette ved at tage udgangspunkt i nogle generelle overvejelser om bybegrebet og en aktuel ramme for forståelse af hvad 'byrum' ...

  2. Mellem lidelse og livsduelighed

    DEFF Research Database (Denmark)

    Dræby, Anders

    Den psykiske lidelse i det moderne samfund er i det væsentlige et udtryk for vanskeligheder med de sociale og kulturelle krav om funktionel livstilpasning. Der præsenteres en anderledes og mere konstruktiv indgang til forståelse af liv og lidelse i vores samtid, der er funderet i et begreb om liv...

  3. Landbruget og kulturlandskabet

    DEFF Research Database (Denmark)

    Rentz-Petersen, Nee

    2011-01-01

    Denne historiske oversigt beskriver, hvordan landbrugets bygninger og driftsformer gennem de sidste 6000 år har tilført kulturlandskabet en dynamik og stadig forvandling. Materialet er udvalgt efter nedslagsmetoden – landbrugets udvikling beskrives i spring, når signifikante ændringer og nyskabel...

  4. Etnicitet og udsathed

    DEFF Research Database (Denmark)

    Tireli, Üzeyir

    2015-01-01

    Kapitlet beskæftiger sig med relationen mellem udsathed og etnicitet og bearbejder spørgsmålet om, hvorfor nogle grupper defineres som udsatte, uden et egentligt empirisk belæg for kausalitetsforhold mellem etnicitet og udsathed. Desuden gives en forklaring på forskellighed i udsathed grupperne i...

  5. Medborgerskab og kulturel mangfoldighed

    DEFF Research Database (Denmark)

    Tireli, Üzeyir

    2017-01-01

    Medborgerskab er et nødvendigt fokus i en tid, der i høj grad er præget af individualisme, ligegyldighed overfor de svage og marginaliserede i samfundet og tilbøjelighed til sekterisme både på bunden og toppen af samfundet. Medborgerskabet kan ses som et modstykke til denne udvikling, idet medbor...

  6. Materialers og komponenters bestandighed

    DEFF Research Database (Denmark)

    Publikationen omfatter 41 indlæg på et nordisk symposium arrangeret af SBI i samarbejde med NORDTEST-BYGG og NBS-MK. Indlæggene giver information om prøvningsmetoder og vurderingskriterier for byggematerialers og -komponenters bestandighed....

  7. Software og kvalitativ dataanalyse

    DEFF Research Database (Denmark)

    Kristiansen, Søren

    Denne bog handler om brug af softwareprogrammer til håndtering og analyse af kvalitative data. Den gengiver og diskuterer nogle af de væsentligste problemstillinger, muligheder og perspektiver, som knytter sig til indførelsen af softwareredskaber til analyse af kvalitative data med udgangspunkt i...

  8. Feedback - evalueringskultur og motivation

    DEFF Research Database (Denmark)

    Dolmer, Grete

    2015-01-01

    I bogen formidles erfaringer og refleksioner med anvendelse af studieaktivitetsmodellen i praksis. Forskellige udfordringer og muligheder belyses, og der identificeres opmærksomhedspunkter til arbejdet med studieaktiviteter i studieaktivitetsmodellens fire kvadranter. Bogen baserer sig på et følg...

  9. Personlighed og motivation

    DEFF Research Database (Denmark)

    Olsen, Jan Brødslev

    2017-01-01

    ses som forskelle i deres personlighed og i deres motivation. Kapitlet er opbygget således, at ganske kort præciseres først de to begreber, personlighed og motivation, hvorefter udvalgte teoretiske perspektiver på personlighed og motivation tages op. Til sammen vil disse bidrage til at besvare...

  10. Mette og Murakami

    DEFF Research Database (Denmark)

    Roesgaard, Marie Højlund

    2017-01-01

    Chiro og Heksene, mange ved at manga er japanske tegneserier, Nationalmuseet laver udstilling om cosplay og opstiller en purikura-maskine, der kan lave billeder af gæsterne i nuttede, storøjede udgaver – så jo, Japan er synlig i Danmark. Mindre kendt er det, at Japan og Danmark allerede under Christian...

  11. Refinansieringsrisiko, DONG og Bankunionen

    DEFF Research Database (Denmark)

    Bechmann, Ken L.

    2014-01-01

    Denne leder indeholder primært redaktørens refleksioner og kommentarer i forlængelse af artiklerne om regulering af refinansieringsrisiko og om salget af aktier i DONG. Endvidere knyttes en række kommentarer til artiklen med Morningstars kritik af ”Om dygtighed, held og stjerner”, der blev bragt ...... Finans/Invest 1/14....

  12. Forsegling og symbiose

    DEFF Research Database (Denmark)

    Bjerregaard Jensen, Lotte

    universelle løsninger, men mere dybtgående ved grundlaget for vor videnskabelige og tekniske kultur. Bjerregaard taler i sin bog om komp!ekset kartesiansk dualisme, naturvidenskab og industrialisme. Op imod denne ”modernitet” sætter hun naturromantikken og etablerer en forbindelse mellem det ”pittoreske...

  13. WTO og skatteret

    DEFF Research Database (Denmark)

    Sørensen, Karsten Engsig

    2005-01-01

    Artiklen analyserer hvordan WTO-retten, særligt GATT-, GATS- og subsidieaftalen, kan påvirke indholdet af national skatteret. Udover en drøftelse af princippet om national behandling og mest begunstigelsesprincippet drøftes hvordan subsidieaftalen kan påvirke de nationale principper om global con...... contra territorial beskatning og reglerne om transfer pricing....

  14. Baggrund og inspiration

    DEFF Research Database (Denmark)

    Rotne, Georg

    2002-01-01

    Illustreret gennemgang af den arkitektoniske anvendelse af beton og betonelementer gennem de sidste 100-150 år. Casestories: Antonio Gandi (1852-1925) og Jørn Utzon (1918-). Afsluttende betragtninger over den aktuelle og fremtidige anvendelse af betonelementer i arkitektur....

  15. Idiomer og improviseret musik

    DEFF Research Database (Denmark)

    2013-01-01

    intuitiv musik / fri improvisation, da denne musikform som et nyt fænomen har brug for at den studerende får nye erfaringer og nye begreber at støtte sig til. Her inddrages også Baileys begreber om idiomatisk / ikke-idiomatisk musik og det senere syn på denne skelnen. Musikeksempler fra undervisningen...

  16. Facebook samtaler og visionsformuleringer

    DEFF Research Database (Denmark)

    Madsen, Anders Koed; Munk, Anders Kristian

    I forbindelse med Aalborg Kommunes visionsproces for fremtidens folkeskole har forfatterne mellem september 2014 og januar 2015 indsamlet og analyseret visionsrelevante indlæg på skoleforvaltningens facebookside. Analysen falder i to dele: 1. En struktureret analyse og indeksering af de visioner,...

  17. Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Høiby, Niels

    2010-01-01

    Pseudomonas aeruginosa is the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed of P. aeruginosa are thought to be the underlying cause of many chronic infections, including those in wounds...... and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour of P. aeruginosa in vitro. A major...

  18. 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...

  19. Environmental, Social og Governance og aktivt ejerskab

    DEFF Research Database (Denmark)

    Bechmann, Ken L.

    2016-01-01

    Den første artikel i dette nummer af Finans/Invest diskuterer Environmental, Social og Governance (ESG) i forhold til at skabe forbedret aktieafkast. Den tredje artikel går i dybden med udviklingen i danske børsnoterede bankers corporate governance karakteristika hen over bankkrisen. ESG og...

  20. Politik og organisation, organisation og politik

    DEFF Research Database (Denmark)

    Christensen, Jørgen Grønnegård

    2006-01-01

    Artiklen beskæftiger isg med samspillet mellem politiske og organisatoriske variable i analysen af administrativ adfærd. Gennem tre casestudier beslyses situationer, hvor skift i politiske præferencer og politisk dagsorden sklår umiddelbart igennem i administrativ praksis (Udlændingestyrelsen), h...

  1. Biofilm Risks

    DEFF Research Database (Denmark)

    Wirtanen, Gun Linnea; Salo, Satu

    2016-01-01

    This chapter on biofilm risks deals with biofilm formation of pathogenic microbes, sampling and detection methods, biofilm removal, and prevention of biofilm formation. Several common pathogens produce sticky and/or slimy structures in which the cells are embedded, that is, biofilms, on various...... surfaces in food processing. Biofilms of common foodborne pathogens are reviewed. The issue of persistent and nonpersistent microbial contamination in food processing is also discussed. It has been shown that biofilms can be difficult to remove and can thus cause severe disinfection and cleaning problems...... in food factories. In the prevention of biofilm formation microbial control in process lines should both limit the number of microbes on surfaces and reduce microbial activity in the process. Thus the hygienic design of process equipment and process lines is important in improving the process hygiene...

  2. Inhibitory effect of farnesol on biofilm formation by Candida tropicalis

    Directory of Open Access Journals (Sweden)

    E Zibafar

    2009-03-01

    Full Text Available ABSTRACT Background: Candidiasis associated with indwelling medical devices is especially problematic since they can act as substrates for biofilm growth which are highly resistant to antifungal drugs. Farnesol is a quorum-sensing molecule that inhibits filamentation and biofilm formation in Candida albicans. Since in recent years Candida tropicalis have been reported as an important and common non-albicans Candida species with high drug resistance pattern, the inhibitory effect of farnesol on biofilm formation by Candida tropicalis was evaluated. Methods: Five Candida tropicalis strains were treated with different concentration of farnesol (0, 30 and 300 µM after 0, 1 and 4 hrs of adherence and then they were maintained under biofilm formation condition in polystyrene, 96-well microtiter plates at 37°C for 48 hrs. Biofilm formation was measured by a semiquantitative colorimetric technique based on reduction assay of 2,3- bis  -2H-tetrazolium- 5- carboxanilide (XTT. Results: The results indicated that the initial adherence time had no effect on biofilm formation and low concentration of farnesol (30 µM could not inhibit biofilm formation. However the presence of non-adherent cells increased biofilm formation significantly and the high concentration of farnesol (300 µM could inhibit biofilm formation. Conclusion: Results of this study showed that the high concentration of farnesol could inhibit biofilm formation and may be used as an adjuvant in prevention and in therapeutic strategies with antifungal drugs.

  3. Heterogeneity in quorum sensing-regulated bioluminescence of Vibrio harveyi.

    Science.gov (United States)

    Anetzberger, Claudia; Pirch, Torsten; Jung, Kirsten

    2009-07-01

    Quorum sensing (QS) refers to the ability of bacterial populations to read out the local environment for cell density and to collectively activate gene expression. Vibrio harveyi, one of the best characterized model organisms in QS, was used to address the question how single cells behave within a QS-activated community in a homogeneous environment. Analysis of the QS-regulated bioluminescence of a wild type strain revealed that even at high cell densities only 69% of the cells of the population produced bioluminescence, 25% remained dark and 6% were dead. Moreover, light intensities greatly varied from cell to cell at high population density. Addition of autoinducer to a bright liquid culture of V. harveyi increased the percentage of luminescent cells up to 98%, suggesting that V. harveyi produces and/or keeps the autoinducers at non-saturating concentrations. In contrast, all living cells of a constitutive QS-active mutant (DeltaluxO) produced light. We also found that QS affects biofilm formation in V. harveyi. Our data provide first evidence that a heterogeneous population produces more biofilm than a homogeneous one. It is suggested that even a QS-committed population of V. harveyi takes advantage of heterogeneity, which extends the current view of QS-regulated uniformity.

  4. Ventilation og luftkvalitet i kontorbygninger

    DEFF Research Database (Denmark)

    Valbjørn, O.; Bach Nielsen, J.; Gunnarsen, Lars Bo

    Udformningen og brugen af kontorbygninger spiller en rolle for luftudvekslingen mellem rummene og derved også for luftkvaliteten. I én mekanisk og to naturligt ventilerede kontorbygninger er ventilationsforhold og luftkvalitet blevet undersøgt med dørene til kontorerne henholdsvis holdt åbne og l...... har adsorption af forureninger på overfladerne en betydning. Effekten vil kunne udnyttes ved hensigtsmæssig projektering og drift....

  5. Ytringsfrihed og blasfemi

    DEFF Research Database (Denmark)

    Schaumburg-Müller, Sten

    2009-01-01

    En redegørelse for forholdet mellem blasfemi, ytringsfrihed og religionsforhånelse. Der argumenteres endvidere for at blasfemibestemmelsen i den danske straffelov ikke udtrykker gældende ret, at det stedse er vanskeligt at finde en balance mellem den vigtige ytringsfrihed og de nødvendige indskræ...... indskrænkninger (såsom børneporne, opfordringer til vold og folkemord) og at beskyttelse af religion ikke har noget med menneskerettigheder at gøre og at forbud mod religionsforhånelse risikerer at stride mod menneskerettighederne....

  6. Mellem bureaukrati og profession

    DEFF Research Database (Denmark)

    Sandholm, Niels; Nielsen, Ulla Søbjerg; Nielsen, Iben Husted

    2015-01-01

    Forhold mellem profession og bureaukrati undersøges med afsæt i to cases, sygeplejersker på hospital og sygehussocialrådgivere. Det empiriske materiale er fokusgruppeinterviews med to grupper af sygeplejersker og to grupper af socialrådgivere. Perspektivet er mikrosociologisk og der trækkes på an....... Et markant fund er, at mens socialrådgiverne fremstår som overvejende loyale overfor klienter, så udtrykker sygeplejerskerne en højere grad af loyalitet med organisatoriske mål og logikker....

  7. Eksistens og natur

    DEFF Research Database (Denmark)

    Pahuus, Mogens

    Eksistens og Natur er et centralt stykke livsfilosofi skrevet af en af dansk filosofis grand old men. Professor emeritus fra Aalborg Universitet Mogens Pahuus præsenterer her den grundidé om mennesket, at ethvert individ er formet i en dobbelthed mellem det givne i os - naturen - og det, at vi fo...... forholder os til det givne - eksistensen. Mogens Pahuus sammenfatter i denne bog sin livsfilosofiske tænkning, og han tør give sig i kast med en stor og systematisk fremstilling af menneskets væsen. Bogen er et modent værk med overskud og overblik....

  8. Salmonella biofilms

    NARCIS (Netherlands)

    Castelijn, G.A.A.

    2013-01-01

    Biofilm formation by Salmonellaspp. is a problem in the food industry, since biofilms may act as a persistent source of product contamination. Therefore the aim of this study was to obtain more insight in the processes involved and the factors contributing to Salmonellabiofilm

  9. Kultur og sundhed

    DEFF Research Database (Denmark)

    kunst- og kulturaktiviteter benyttes på sundhedsområdet? Antologien "Kultur og sundhed" præsenterer en bred platform af forskellige praksisser, bidrager til vidensgrundlaget og diskursen i feltet og skaber inspiration til fremtidige, sundhedsfremmende tilbud i Danmark ved at afsøge muligheder i...... krydsfeltet mellem sundhed, trivsel og kunst- og kulturaktiviteter. Bogen er opdelt i tre dele hvor den første del fokuserer på en række af de forståelser, begreber, tilgange, vidensgrundlag og mekanismer der er i spil i det tværfaglige felt. Bogens anden del er koncentreret om en bred præsentation af feltets...

  10. Role and regulation of the orphan AphA protein of quorum sensing in pathogenic Vibrios.

    Science.gov (United States)

    Lu, Renfei; Osei-Adjei, George; Huang, Xinxiang; Zhang, Yiquan

    2018-03-01

    Quorum sensing (QS), a cell-to-cell communication process, is widely distributed in the bacterial kingdom. Bacteria use QS to control gene expression in response to cell density by detecting the signal molecules called autoinducers. AphA protein is the master QS regulator of vibrios operating at low cell density. It regulates the expression of a variety of genes, especially those encoding virulence factors, flagella/motility and biofilm formation. The role and regulation of AphA in vibrios, especially in human pathogenic vibrios, are summarized in this review. Clarification of the roles of AphA will help us to understand the pathogenesis of vibrios.

  11. Triazole-containing N-acyl homoserine lactones targeting the quorum sensing system in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert; Jakobsen, Tim H.; Bang, Claus Gunnar

    2015-01-01

    the pathogenesis and antibiotic tolerance of a bacterial biofilm. To identify the structural elements important for antagonistic or agonistic activity against the Pseudomonas aeruginosa LasR protein, we report the synthesis and screening of new triazole-containing mimics of natural N-acyl homoserine lactones....... A series of azide- and alkyne-containing homoserine lactone building blocks was used to prepare an expanded set of 123 homoserine lactone analogues through a combination of solution- and solid-phase synthesis methods. The resulting compounds were subjected to cell-based quorum sensing screening assays...

  12. How to desynchronize quorum-sensing networks

    Science.gov (United States)

    Russo, Giovanni

    2017-04-01

    In this paper we investigate how so-called quorum-sensing networks can be desynchronized. Such networks, which arise in many important application fields, such as systems biology, are characterized by the fact that direct communication between network nodes is superimposed to communication with a shared, environmental variable. In particular, we provide a new sufficient condition ensuring that the trajectories of these quorum-sensing networks diverge from their synchronous evolution. Then, we apply our result to study two applications.

  13. Konstruktion, rekonstruktion og strategiske essentialismer

    DEFF Research Database (Denmark)

    Borup, Jørn

    2007-01-01

    Essentialisme og dennes misrepræsentation, etnocentrisme og hegemoni (som afsløret af eksempelvis postkoloniale studier) er et af de vigtigste kritikpunkter mod før-postmoderne religions- og kulturstudier. Denne artikel hævder, at konstruktioner ("opfindelser") og essentialismer er naturlige og...

  14. Om standpunkter, interesser og behov

    DEFF Research Database (Denmark)

    Adrian, Lin

    2008-01-01

    Begreberne standpunkter, interesser og behov er hyppigt anvendte begreber i mæglingslitteraturen. Deres betydning tages ofte for givet og underkastes sjældent selvstændig definition og analyse. Artiklen undersøger begrebernes oprindelse og betydning og diskuterer deres rolle i mæglingspraksis. Ar...

  15. Cases om organisation og ledelse

    DEFF Research Database (Denmark)

    Sinding, Knud; Bøllingtoft, Anne

    Cases gør det muligt at øve sig og giver mange forskellige problemstillinger at arbejde med, end de fleste kommer i nærheden af i deres arbejde. Samlingen her passer til en bred vifte af organisationsfag. Der er navnløse og navngivne, store og små, offentlige og private, kendte og ukendte. Casene...

  16. Patterned biofilm formation reveals a mechanism for structural heterogeneity in bacterial biofilms.

    Science.gov (United States)

    Gu, Huan; Hou, Shuyu; Yongyat, Chanokpon; De Tore, Suzanne; Ren, Dacheng

    2013-09-03

    Bacterial biofilms are ubiquitous and are the major cause of chronic infections in humans and persistent biofouling in industry. Despite the significance of bacterial biofilms, the mechanism of biofilm formation and associated drug tolerance is still not fully understood. A major challenge in biofilm research is the intrinsic heterogeneity in the biofilm structure, which leads to temporal and spatial variation in cell density and gene expression. To understand and control such structural heterogeneity, surfaces with patterned functional alkanthiols were used in this study to obtain Escherichia coli cell clusters with systematically varied cluster size and distance between clusters. The results from quantitative imaging analysis revealed an interesting phenomenon in which multicellular connections can be formed between cell clusters depending on the size of interacting clusters and the distance between them. In addition, significant differences in patterned biofilm formation were observed between wild-type E. coli RP437 and some of its isogenic mutants, indicating that certain cellular and genetic factors are involved in interactions among cell clusters. In particular, autoinducer-2-mediated quorum sensing was found to be important. Collectively, these results provide missing information that links cell-to-cell signaling and interaction among cell clusters to the structural organization of bacterial biofilms.

  17. Teorien om alt og andre artikler om sprog og filosofi

    DEFF Research Database (Denmark)

    Artikelsamling i anledning af Peter Widells 60-års fødselsdag, med emnerne: 1. Stilistik og litteraturvidenskab  (7 artikler), 2. Leksikografi, semantik og grammatik (10 artikler), 3. Sprogfilosofi, sprogpsykologi og metaforteori (10 artikler)....

  18. Etik og kommunikation

    Directory of Open Access Journals (Sweden)

    Uwe Geist

    1996-09-01

    Full Text Available "Det er ikke helt tilfældigt, at etik og PR ekspanderer voldsomt i 80´ernes Europa, og PR nærmer sig etikken. Begge dele er affødt af dybtgående forandringer i livsbetingelserne, som er beskrevet mange steder. Forurening, globalisering, polarisering mellem rig og fattig, genmanipulation og informationseksplosion er de gennemgå- ende motiver og et truende kaos det gennemgående tema". Det er på den baggrund, at Uwe Geist, der er ansat på Roskilde Universitets- centers Dansk/PR-uddannelse, i artiklen prøver at komme bag om et modeord, som i de senere år har hærget både samfundet i almindelig- hed og PR-branchen i særdeleshed. I artiklen sætter han først begre- bet "etik" op imod beslægtede begreber som "moral", "høflighed" og "ret". Dernæst diskuterer han etikkens nødvendighed, på den ene side inden for Habermas´ teori om kommunikativ handlen og diskurs, livs- verden og systemverden, hvor etik ikke handler om faste normer for godt og ondt, men om gensidigheden som grundnorm; på den anden side inden for Luhmanns systemteori, hvor gensidighed ganske vist er funktions- og effektivitetsorienteret, men ikke kan undvære mekanis- men og ressourcen "tillid". Fordi artiklen omhyggeligt forklarer de cen- trale begreber, den diskuterer, kan den både fungere begrebsintrodu- cerende for læsere uden omfattende forudsætninger på feltet, og be- grebsafklarende for mere indviede læsere.

  19. 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...

  20. Roles of Extracellular Polysaccharides and Biofilm Formation in Heavy Metal Resistance of Rhizobia

    OpenAIRE

    Natalia Nocelli; Pablo C. Bogino; Erika Banchio; Walter Giordano

    2016-01-01

    Bacterial surface components and extracellular compounds, particularly flagella, lipopolysaccharides (LPSs), and exopolysaccharides (EPSs), in combination with environmental signals and quorum-sensing signals, play crucial roles in bacterial autoaggregation, biofilm development, survival, and host colonization. The nitrogen-fixing species Sinorhizobium meliloti (S. meliloti) produces two symbiosis-promoting EPSs: succinoglycan (or EPS I) and galactoglucan (or EPS II). Studies of the S. melilo...

  1. Institutionernes, ledernes og medarbejdernes succeskriterier - og Strukturreformen

    DEFF Research Database (Denmark)

    Pedersen, John Storm

    2007-01-01

    På grundlag af en repræsentativ spørgeskemaundersøgelse blandt institutionsledere i de danske offentlige kommunale driftsinstitutioner analyseres institutionernes, ledernes og medarbejdernes succeskriterier blandt andet set i lyset af Strukturreformen...

  2. Quorum Quenching Revisited—From Signal Decays to Signalling Confusion

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-04-01

    Full Text Available In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing, others are interrupting the communication (quorum quenching, thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely accepted, the actual roles of these quorum quenching enzymes are now being uncovered. Recent evidence extends the role of quorum quenching to detoxification or metabolism of signalling molecules as food and energy source; this includes “signalling confusion”, a term coined in this paper to refer to the phenomenon of non-destructive modification of signalling molecules. While quorum quenching has been explored as a novel anti-infective therapy targeting, quorum sensing evidence begins to show the development of resistance against quorum quenching.

  3. Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid

    Directory of Open Access Journals (Sweden)

    Cláudia N. H. Marques

    2015-11-01

    Full Text Available Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation.

  4. Quorum sensing determines the choice of antiphage defense strategy in Vibrio anguillarum

    DEFF Research Database (Denmark)

    Tan, Demeng; Svenningsen, Sine Lo; Middelboe, Mathias

    2015-01-01

    of the outcome of phage-bacterial encounters in the fish pathogen Vibrio anguillarum is bacterial cell-cell communication, known as quorum sensing. Specifically, V. anguillarum PF430-3 cells locked in the low-cell-density state (ΔvanT mutant) express high levels of the phage receptor OmpK, resulting in a high...... susceptibility to phage KVP40, but achieve protection from infection by enhanced biofilm formation. By contrast, cells locked in the high-cell-density state (ΔvanΟ mutant) are almost completely unsusceptible due to quorum-sensing-mediated downregulation of OmpK expression. The phenotypes of the two quorum......-sensing mutant strains are accurately reflected in the behavior of wild-type V. anguillarum, which (i) displays increased OmpK expression in aggregated cells compared to free-living variants in the same culture, (ii) displays a clear inverse correlation between ompK mRNA levels and the concentration of N...

  5. Screening of Natural Product Derivatives Identifies Two Structurally Related Flavonoids as Potent Quorum Sensing Inhibitors against Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Suvi Manner

    2018-05-01

    Full Text Available Owing to the failure of conventional antibiotics in biofilm control, alternative approaches are urgently needed. Inhibition of quorum sensing (QS represents an attractive target since it is involved in several processes essential for biofilm formation. In this study, a compound library of natural product derivatives (n = 3040 was screened for anti-quorum sensing activity using Chromobacterium violaceum as reporter bacteria. Screening assays, based on QS-mediated violacein production and viability, were performed in parallel to identify non-bactericidal QS inhibitors (QSIs. Nine highly active QSIs were identified, while 328 compounds were classified as moderately actives and 2062 compounds as inactives. Re-testing of the highly actives at a lower concentration against C. violaceum, complemented by a literature search, led to the identification of two flavonoid derivatives as the most potent QSIs, and their impact on biofilm maturation in Escherichia coli and Pseudomonas aeruginosa was further investigated. Finally, effects of these leads on swimming and swarming motility of P. aeruginosa were quantified. The identified flavonoids affected all the studied QS-related functions at micromolar concentrations. These compounds can serve as starting points for further optimization and development of more potent QSIs as adjunctive agents used with antibiotics in the treatment of biofilms.

  6. Frivillig og under eget ansvar

    DEFF Research Database (Denmark)

    Bang, Karin

    2002-01-01

    Ifølge Lou Andreas-Salomé drejer flere af Henrik Ibsens dramaer sig om problemet med at skabe balance mellem selvbefrielse og selvbegrænsning, og nøgleordene er: Frivillig og under eget ansvar....

  7. Følelser og sociologi

    DEFF Research Database (Denmark)

    Bo, Inger Glavind; Jacobsen, Michael Hviid

    2017-01-01

    En introduktion til bogen om følelsernes sociologi eller emotionssociologi - herunder om den ekspressive revolution og den affektive vending, om forskning i følelser og dens klassifikationer, tilgange, teorier og metoder....

  8. Professionsetik indefra og udefra

    DEFF Research Database (Denmark)

    Dige, Morten

    & Childress' fire principper for medicinsk etik: godgørenhed, ikke-skadevolden, retfærdighed og respekt for autonomi. Mange organisationers og professioners værdigrundlag er bygget op om værdier som bedst lader sig forstå som denne type: respekt, ligeværdighed, troværdighed, omsorg, tillid, værdighed osv. Den....... Jeg finder en besindelse på og oprustning af denne etiske kerne af afgørende betydning i en tid, hvor hjælpeprofessionernes autonomi og troværdighed sættes under pres af markedsdrevne og bureaukratiske logikker ("New Public Managment"). Jeg illustrerer dette med cases fra socialt arbejde og...

  9. Medier - love og regler

    DEFF Research Database (Denmark)

    Jørgensen, Oluf

    Den mest komplette samling af de love og regler, der har størst betydning for medier og journalistik i Danmark. Samlingen ajourføres, når Folketinget lukker i juni, og alle nye bestemmelser dermed er kendt. Ændringer siden sidste udgave: Lovbogen er ajourført med ændringer i arkivloven, miljøoply......Den mest komplette samling af de love og regler, der har størst betydning for medier og journalistik i Danmark. Samlingen ajourføres, når Folketinget lukker i juni, og alle nye bestemmelser dermed er kendt. Ændringer siden sidste udgave: Lovbogen er ajourført med ændringer i arkivloven...

  10. Religion, migration og integration

    DEFF Research Database (Denmark)

    Borup, Jørn

    2010-01-01

    Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i integrationss......Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i...

  11. Migration og etnicitet

    DEFF Research Database (Denmark)

    Christiansen, Connie Carøe

    2004-01-01

    Migration og etnicitet er aktuelle og forbundne fænomener, idet migration øger berøringsfladerne mellem befolkningsgrupper. Etniciteter formes i takt med at grænser drages imellem disse grupper. Imod moderniserings-teoriernes forventning forsvandt etnicitet ikke som en traditionel eller oprindelig...... måde at skabe tilhørsforhold på; globalt set fremstår vor tid istedet som en "migrationens tidsalder", der tilsyneladende også er en tidsalder, hvor kulturelle særtræk, i form af etnicitet, udgør vigtige linjer, hvorefter grupper skilller sig ud fra hinanden. Både migration og etnicitet bringer fokus...... den finder sted i modtagerlandet, men nyere perspektiver på migration, som begreber om medborgerskab, transnationalisme og diaspora er eksponenter for, søger udover den nationalstatslige ramme og inddrager konsekvenserne af migrationen for afsenderlande....

  12. Menneskets hjerne og personlighed

    DEFF Research Database (Denmark)

    Mathiesen, Birgit Bork; Thomsen, Marianne Skovgaard

    2017-01-01

    været stigende, siden en gruppe af danske psykiatere og psykologer i 1988 afholdt den første internationale kongres om personlighedsforstyrrelser i København og dannede Institut for Personlighedsteori og Psykopatologi (IPTP). Da IPTP afholdt sit 25-års jubilæum, besluttede man at udgive en bog, der...... indeholder al den viden, man har opnået på området gennem de seneste 25 års forskning. Resultatet er Personlighed og personlighedsforstyrrelser. En grundbog. Bogens redaktører er professor Erik Simonsen og lektor Birgit Bork Mathiesen, der er henholdsvis formand og næstformand for IPTP. De har begge gennem...

  13. Menneskerettighederne og Holocaust

    DEFF Research Database (Denmark)

    Wæhrens, Anne

    2012-01-01

    Menneskerettighederne er i dag et centralt element i de fleste demokratiske staters opbygning, og de er afgørende for staternes forståelse af sig selv. Holocaust og menneskerettighederne bliver ofte set som forbundne, men er de det? Hvor står menneskerettighederne i dag? Og hvad gør man for at fo......Menneskerettighederne er i dag et centralt element i de fleste demokratiske staters opbygning, og de er afgørende for staternes forståelse af sig selv. Holocaust og menneskerettighederne bliver ofte set som forbundne, men er de det? Hvor står menneskerettighederne i dag? Og hvad gør man...

  14. Mentaliseringsbaseret behandling og musikterapi

    Directory of Open Access Journals (Sweden)

    Niels Hannibal

    2013-06-01

    Full Text Available Denne artikel behandler spørgsmålet, om mentaliseringsbaseret terapi er en metode der medfører et skift i terapeutisk forholdemåde for analytisk orienterede musikterapeuter i arbejde med patienter med personlighedsforstyrrelse. Artiklen skal ses om en del af den teoretiske integrationer af MBT i musikterapi med denne målgruppe. Artiklen ser på de forskrifter til mentaliseringsfremmende tiltag som Allan, Fonagy og Bateman (2010 beskriver. Artiklens konklusion er dels af MBT’s krav til forholdemåde og interventionsfokus er et skift i forhold til traditionel analytisk orienteret terapi, bl.a. i forhold til fokus på her og nu, og øget fokus på implicit relationel læring, men siger samtidig at musikterapi allerede lever op til og i forvejen anvender disse elementer i musikterapi qua ligheden mellem klinisk improvisation (Wigram 2004 og implicit relationel viden (Stern 2010.

  15. Erving Goffman og Axel Honneth - Anerkendelse og krænkelse

    OpenAIRE

    Hansen, Annemette E

    2006-01-01

    En kombination af Erving Goffmans teorier om stigma og rollespil og Axel Honneths anerkendelsesteori En kombination af Erving Goffmans teorier om stigma og rollespil og Axel Honneths anerkendelsesteori

  16. Mitigation of membrane biofouling by a quorum quenching bacterium for membrane bioreactors.

    Science.gov (United States)

    Ham, So-Young; Kim, Han-Shin; Cha, Eunji; Park, Jeong-Hoon; Park, Hee-Deung

    2018-06-01

    In this study, a quorum-quenching (QQ) bacterium named HEMM-1 was isolated at a membrane bioreactor (MBR) plant. HEMM-1 has diplococcal morphology and 99% sequence identity to Enterococcus species. The HEMM-1 cell-free supernatant (CFS) showed higher QQ activities than the CFS of other QQ bacteria, mostly by degrading N-acyl homoserine lactones (AHLs) with short acyl chains. Instrumental analyses revealed that HEMM-1 CFS degraded AHLs via lactonase activity. Under static, flow, and shear conditions, the HEMM-1 CFS was effective in reducing bacterial and activated-sludge biofilms formed on membrane surfaces. In conclusion, the HEMM-1 isolate is a QQ bacterium applicable to the control of biofouling in MBRs via inhibition of biofilm formation on membrane surfaces. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. IT og Innovation

    DEFF Research Database (Denmark)

    Nordbjerg, Finn Ebertsen; Andersen, Poul

    IT og innovation behandles ud fra tre perspektiver: IT-udviklingsprocesser, IT og lærende organisation og IT-understøttelse af en innovativ didaktik. Vi beskriver nogle ideer til, hvordan arbejdsformer anvendt i forbindelse med ITudviklingsprocesser kan inspirere en innovativ didaktik. IT...... beskrives nogle idéer til, hvordan IT-værktøjer kan understøtte innovative læreprocesser....

  18. Materialer, overflade- og procesteknologi

    DEFF Research Database (Denmark)

    Alsted Rasmussen, Anette; Somers, Marcel A. J.; Pihl, Niels Henrik

    2013-01-01

    Rengøring udgør en væsentlig del af danske slagteriers og mejeriers daglige arbejde. Cirka 20 procent af branchens driftsomkostninger allokeres til løsning og håndtering af problemstillinger, der er forbundet til rengøring. Rengøringsprocesser på slagterier og mejerier er i dag forbundet med et h...

  19. Unge og gambling

    DEFF Research Database (Denmark)

    Nielsen, Jens Christian; Sørensen, Niels Ulrik; Wittendorff, Nina

    Rapporten offentliggør resultaterne af den første videnskabelige undersøgelse af pengespil blandt unge danskere mellem 12 og 17 år. Den beskæftiger sig med tre områder 1) Pengespiladfærd blandt unge, 2) Problemspiladfærd blandt unge og 3) Sammenhænge mellem unges risikoadfærd og trivsel samt dere...

  20. Adoption og diskrimination

    DEFF Research Database (Denmark)

    Henze-Pedersen, Sofie

    2017-01-01

    I denne undersøgelse har vi gennemført interview med både internationalt adopterede og dansk adopterede og har derfor mulighed for at nuancere adopteredes oplevelser af diskrimination. Det bliver således muligt at belyse, hvornår og på hvilken måde det at have et etnisk udseende, der adskiller si...

  1. Klima og turisme

    DEFF Research Database (Denmark)

    Ren, Carina Bregnholm

    2014-01-01

    Denne artikel præsenterer en række koblinger mellem klima og turisme med det formål at pege på, hvorledes klima og turisme i fremtiden kan tænkes. Jeg beskriver, hvorledes man i turismeforskningen har fokuseret på at blotlægge særligt to kausale forbindelser mellem klima og turisme, nemlig hvorda...

  2. Kognition og kultur

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2008-01-01

      Igennem det meste af det 20. årh. har akademisk religionsteori været baseret på et kulturparadigme, som ignorerede eller direkte afviste at inddrage biologi og evolution. Med tilkomsten siden 1990'erne af kognitive studier og disses indflydelse på religionsvidenskaben er denne situation ændret ...... ‒ det som er formuleret af bl.a. Emile Durkheim og Roy A. Rappaport....

  3. Oplevelsesanalyse og arkitektur

    DEFF Research Database (Denmark)

    Nagbøl, Søren Peter

    styrer ikke blot de fysiske begrænsninger, den sætter for os, men også de sociale og psykiske processer, der næsten i al forskning har været upåagtet. Samtidig repræsenterer og symboliserer arkitekturen den tid de er opført i. Alt dette analyseres i bogen ved udvikling af metoder forbindelse med konkrete...

  4. Systemisk og narrativ familieteori

    DEFF Research Database (Denmark)

    Rasmussen, Svend Aage

    2010-01-01

    Spiseforstyrrelser som anoreksi og bulimi har op gennem det 20. århundrede og især inden for de sidste 50 år været et stigende problem i den vestlige verden. Problemet er særlig udbredt blandt unge kvinder, der står på tærsklen til voksenverdenen, og har store omkostninger af såvel psykologisk som...

  5. Darwinisme, film og filmteori

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh

    2010-01-01

    Artiklen giver først en oversigt over evolutionshistorisk baseret kulturanalyse og dennes tilknytning til neuropsykologi, herunder evolutionsteoretiske studier af religion og andre overnaturlige forestillingssystemer. Derefter redegøres der kort for, hvorledes Darwinismen har  stødt på modstand, ...... kulturhistoriske baggrund for retssag og film.   Keywords: evolutionsteori, filmteori, evolutionær religionsanalyse, Inherit the wind.     Udgivelsesdato: april 2010...

  6. Analyse og design af produktionssystemer

    DEFF Research Database (Denmark)

    Johansen, John; Riis, Jens Ove; Arlbjørn, Jan Stentoft

    lys, men til vores store glæde og overraskelse har vi erfaret, at dele af materialet stadigvæk er anvendt på en del ingeniør- og økonomiuddannelser i Danmark. Nogle af de tanker og metoder som blev udviklet i ViPSprogrammet har overlevet og opfattes fortsat som relevante og anvendelige også til...

  7. Luhmann og Organisation

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2008-01-01

      Synopsis - Vi vil i denne artikel udlægge Luhmanns organisationsteori i et fugleperspektiv. Ud fra en videnskabsteoretisk og metametodologisk vinkel henvender vi os især til interesserede i organisationsteori og organisationskommunikation, som gerne vil tilegne sig Luhmanns organisationsteori i...... bevæger sig videre til systembegrebet, forskellige systemtyper, kommunikationsbegrebet og til sidst organisations- og beslutningsbegrebet. Alt i alt er det artiklens ærinde at blotlægge de begrebslige præmisser for Luhmanns organisationsteori....

  8. Kognitiv pragmatikk og relevansteori

    OpenAIRE

    Falkum, Ingrid Lossius; Kjøll, Georg

    2014-01-01

    Pragmatikk som fagfelt kan defineres som studier av språk i bruk, og kan i sin videste form omfatte undersøkelser av både kognitive, sosiale og kulturelle aspekter ved kommunikasjon (Verschueren et al. 1995: 2). Kognitiv pragmatikk er, som navnet antyder, den undergrenen av pragmatikken som søker å forstå hvordan kommunikasjon oppstår på bakgrunn av menneskets kognitive og språklige evner. Mens sosiopragmatikken vil være opptatt av å undersøke fenomener som høflighet, sosiale roller, makt og ...

  9. Tegn og gerninger

    DEFF Research Database (Denmark)

    Togeby, Ole

    2005-01-01

    Begrebet 'tegn' eller 'repræsentation' defineres som noget der for nogen angiver noget som det er udformet til at angive. Der skelnes dernæst mellem analoge og digitale repræsentationer, blandingsrepræsentationer og komplekse repræsentationer.......Begrebet 'tegn' eller 'repræsentation' defineres som noget der for nogen angiver noget som det er udformet til at angive. Der skelnes dernæst mellem analoge og digitale repræsentationer, blandingsrepræsentationer og komplekse repræsentationer....

  10. Voksenuddannelse og regional udvikling

    DEFF Research Database (Denmark)

    Rasmussen, Palle

    2008-01-01

    Med udgangspunkt i regionale og lokale forskelle uddannelsesforskelle behandler artiklen uddannelsers rolle i regional udvikling. Der lægges særlig vægt på forskellige former for voksenuddannelse. Hvad betyder udviklingen mod vidensamfundet for udviklingen i erhverv, beskæftigelse og sociale...... forhold? Hvilken rolle spiller uddannelse i centerområder og udkantsområder? Hvordan kan uddannelse og læring bidrage til regional udvikling? Hvilke roller kan voksenuddannelse have i denne sammenhæng?...

  11. Musik og psykologi

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    Temanummeret om Musik og Psykologi skrives af over 20 bidragydere, heraf 5 udlændinge, med baggrund i musikpsykologi, musikterapi, musikvidenskab, hjerneforskning mm. Der vil være både teoretiske, kliniske og kombineret teoretisk-kliniske artikler.......Temanummeret om Musik og Psykologi skrives af over 20 bidragydere, heraf 5 udlændinge, med baggrund i musikpsykologi, musikterapi, musikvidenskab, hjerneforskning mm. Der vil være både teoretiske, kliniske og kombineret teoretisk-kliniske artikler....

  12. Biofilm Infections

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Moser, Claus Ernst

    A still increasing interest and emphasis on the sessile bacterial lifestyle biofilms has been seen since it was realized that the vast majority of the total microbial biomass exists as biofilms. Aggregation of bacteria was first described by Leeuwenhoek in 1677, but only recently recognized...... as being important in chronic infection. In 1993 the American Society for Microbiology (ASM) recognized that the biofilm mode of growth was relevant to microbiology. This book covers both the evidence for biofilms in many chronic bacterial infections as well as the problems facing these infections...... such as diagnostics, pathogenesis, treatment regimes and in vitro and in vivo models for studying biofilms. This is the first scientific book on biofilm infections, chapters written by the world leading scientist and clinicians. The intended audience of this book is scientists, teachers at university level as well...

  13. Strategies for combating bacterial biofilms: A focus on anti-biofilm agents and their mechanisms of action

    Science.gov (United States)

    Roy, Ranita; Tiwari, Monalisa; Donelli, Gianfranco; Tiwari, Vishvanath

    2018-01-01

    ABSTRACT Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby

  14. Experimental and Theoretical Investigation of Multispecies Oral Biofilm Resistance to Chlorhexidine Treatment

    Science.gov (United States)

    Shen, Ya; Zhao, Jia; de La Fuente-Núñez, César; Wang, Zhejun; Hancock, Robert E. W.; Roberts, Clive R.; Ma, Jingzhi; Li, Jun; Haapasalo, Markus; Wang, Qi

    2016-06-01

    We investigate recovery of multispecies oral biofilms following chlorhexidine gluconate (CHX) and CHX with surface modifiers (CHX-Plus) treatment. Specifically, we examine the percentage of viable bacteria in the biofilms following their exposure to CHX and CHX-Plus for 1, 3, and 10 minutes, respectively. Before antimicrobial treatment, the biofilms are allowed to grow for three weeks. We find that (a). CHX-Plus kills bacteria in biofilms more effectively than the regular 2% CHX does, (b). cell continues to be killed for up to one week after exposure to the CHX solutions, (c). the biofilms start to recover after two weeks, the percentage of the viable bacteria recovers in the 1 and 3 minutes treatment groups but not in the 10 minutes treatment group after five weeks, and the biofilms fully return to the pretreatment levels after eight weeks. To understand the mechanism, a mathematical model for multiple bacterial phenotypes is developed, adopting the notion that bacterial persisters exist in the biofilms together with regulatory quorum sensing molecules and growth factor proteins. The model reveals the crucial role played by the persisters, quorum sensing molecules, and growth factors in biofilm recovery, accurately predicting the viable bacterial population after CHX treatment.

  15. Experimental and Theoretical Investigation of Multispecies Oral Biofilm Resistance to Chlorhexidine Treatment

    Science.gov (United States)

    Shen, Ya; Zhao, Jia; de la Fuente-Núñez, César; Wang, Zhejun; Hancock, Robert E. W.; Roberts, Clive R.; Ma, Jingzhi; Li, Jun; Haapasalo, Markus; Wang, Qi

    2016-01-01

    We investigate recovery of multispecies oral biofilms following chlorhexidine gluconate (CHX) and CHX with surface modifiers (CHX-Plus) treatment. Specifically, we examine the percentage of viable bacteria in the biofilms following their exposure to CHX and CHX-Plus for 1, 3, and 10 minutes, respectively. Before antimicrobial treatment, the biofilms are allowed to grow for three weeks. We find that (a). CHX-Plus kills bacteria in biofilms more effectively than the regular 2% CHX does, (b). cell continues to be killed for up to one week after exposure to the CHX solutions, (c). the biofilms start to recover after two weeks, the percentage of the viable bacteria recovers in the 1 and 3 minutes treatment groups but not in the 10 minutes treatment group after five weeks, and the biofilms fully return to the pretreatment levels after eight weeks. To understand the mechanism, a mathematical model for multiple bacterial phenotypes is developed, adopting the notion that bacterial persisters exist in the biofilms together with regulatory quorum sensing molecules and growth factor proteins. The model reveals the crucial role played by the persisters, quorum sensing molecules, and growth factors in biofilm recovery, accurately predicting the viable bacterial population after CHX treatment. PMID:27325010

  16. Samtalekarismaet og symmetriproblemet

    Directory of Open Access Journals (Sweden)

    Tobias Dam Hede

    2011-12-01

    Full Text Available Artiklen argumenterer for at coachingdiskursen ikke primært har sin oprindelse i sporten, men derimod i en fleksibel model for sammenhængen mellem ledelse, subjektivitet og erkendelse. Med inspiration fra Michel Foucault udvikles en analysestrategi - truth game analysis - der kan operere på to niveauer, som ellers kan være svære at forene: det genealogiske niveau og det empiriske niveau. Det centrale tema i analysen er udviklingen af teknikker og praksisser for, hvordan en professionel samtalepartner kan bistå et andet menneske med at vende sig imod det, der er særligt væsentligt for den enkelte selv og det fællesskab, han definerer sig i forhold til. Dermed bliver coachingforløbet forpligtet på en "sandhedskontrakt", hvor "vendingerne imod det væsentlige" bliver de afgørende sandhedsproducerende momenter for samtalens udvikling og resultat. Artiklen konstruerer begrebet samtalekarismaet som den betegnelse for den effekt, hvor coachee i kraft af samtalen oplever at få del i en rigere forståelse af sig selv og sine muligheder. Problemet er at erkendelsesarbejdet i samtalen er betinget af en række udfordringer, som har med samtalens socialitet og interaktion at gøre, dvs. samtalens praktiske tilegnelse på trods af og ved hjælp af: Ulige fordeling af magt, frihed, position og autoritet, ulige fordeling af rettigheder og pligter til at spørge og svare; blandede motiver i forhold til, hvad den ene vil opnå af den anden og omvendt - og altså alt det, der hører til det projektive univers som grundvilkår for samtalens udvikling, vedligeholdelse - og mulige sammenbrud. Disse udfordringer håndteres under samtalebetegnelsen symmetriproblemet, som samtidig bygger på en antagelse (jeg-du-hypotesen om at samtalens effektivitet som strategi for subjektivitet og erkendelse forudsætter udviklingen af en særlig relationel kvalitet imellem de samtalende, som går på tværs af samtalens komplekse fordeling af strategiske ressourcer

  17. Isolate-specific effects of patulin, penicillic Acid and EDTA on biofilm formation and growth of dental unit water line biofilm isolates.

    Science.gov (United States)

    Liaqat, Iram; Bachmann, Robert Thomas; Sabri, Anjum Nasim; Edyvean, Robert G J

    2010-08-01

    Dental unit water line (DUWL) contamination by opportunistic pathogens has its significance in nosocomial infection of patients, health care workers, and life-threatening infections to immunocompromized persons. Recently, the quorum sensing (QS) system of DUWL isolates has been found to affect their biofilm-forming ability, making it an attractive target for antimicrobial therapy. In this study, the effect of two quorum-sensing inhibitory compounds (patulin; PAT, penicillic acid; PA) and EDTA on planktonic growth, AI-2 signalling and in vitro biofilm formation of Pseudomonas aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. was monitored. Vibrio harveyi BB170 bioassay and crystal violet staining methods were used to detect the AI-2 monitoring and biofilm formation in DUWL isolates, respectively. The V. harveyi BB170 bioassay failed to induce bioluminescence in A. xylosoxidans and Achromobacter sp., while P. aeruginosa showed AI-2 like activity suggesting the need of some pretreatments prior to bioassay. All strains were found to form biofilms within 72 h of incubation. The QSIs/EDTA combination have isolate-specific effects on biofilm formation and in some cases it stimulated biofilm formation as often as it was inhibited. However, detailed information about the anti-biofilm effect of these compounds is still lacking.

  18. Sex og orientalisme

    DEFF Research Database (Denmark)

    Necef, Mehmet Ümit

    2007-01-01

    I sit indflydesesrige værk ''Orientalisme'' nærmest dæmoniserer den palæstinensisk-amerikanske litteraturprofessor Edward Said de seksuelle relationer mellem orientalere og vestlige intellektuelle, der i 1800- og 1900-tallet rejste i Orienten. Men ved at udelukke centrale aspekter af den seksuali...

  19. Forskningsbaseret og kompetencerettet undervisning

    DEFF Research Database (Denmark)

    Ravn-Jonsen, Lars

    2014-01-01

    På Miljø og ressource management (MRM) ser vi ikke forskningsbaseret undervisning, som blot præsentation af nyeste viden, eller undervisning af forskere; men anser forskningsbaseret undervisning som en didaktisk tilgang, hvor de studerende deltager i forskningslignende aktiviteter, og derved bliv...

  20. Rejsebilleder og selvfremstilling

    DEFF Research Database (Denmark)

    Fausing, Bent

    2016-01-01

    Om rejsens betydning for at tage billeder og for selvfremstilling. Især når vi er ude at rejse, deler vi vores hverdag med både familie, venner og fremmede. Denne selvfremstilling skaber et nyt forhold til de oplevelser, som vi møder på vores rejser....

  1. Kant og stoisk kosmopolitisme

    DEFF Research Database (Denmark)

    Nussbaum, Martha C.

    2004-01-01

    Oversættelse af Martha C. Nussbaums artikel om Kant og stoisk kosmopolitisme til Slagmarks temanummer "Kosmopolis"......Oversættelse af Martha C. Nussbaums artikel om Kant og stoisk kosmopolitisme til Slagmarks temanummer "Kosmopolis"...

  2. Kommunikation og sprog

    DEFF Research Database (Denmark)

    Togeby, Ole

    2009-01-01

    Oversigt over hvilke modeller der findes for sprogets rolle i kommunikation: Shannon og Weaver, Saussure, Peirce, Austin, Searle, Grice, Bloomfield, Ogden & Richards, Bateson, Watzlawick, Roman Jakobson,......Oversigt over hvilke modeller der findes for sprogets rolle i kommunikation: Shannon og Weaver, Saussure, Peirce, Austin, Searle, Grice, Bloomfield, Ogden & Richards, Bateson, Watzlawick, Roman Jakobson,...

  3. Kommunikation og sprog

    DEFF Research Database (Denmark)

    Togeby, Ole

    2016-01-01

    Oversigt over hvilke modeller der findes for sprogets rolle i kommunikation: Shannon og Weaver, Saussure, Peirce, Austin, Searle, Grice, Bloomfield, Ogden & Richards, Bateson, Watzlawick, Roman Jakobson,......Oversigt over hvilke modeller der findes for sprogets rolle i kommunikation: Shannon og Weaver, Saussure, Peirce, Austin, Searle, Grice, Bloomfield, Ogden & Richards, Bateson, Watzlawick, Roman Jakobson,...

  4. Spillefilm og kollektiv historiebevidsthed

    DEFF Research Database (Denmark)

    2016-01-01

    Valg af materiale/medie/form: Video med person og skærm (Picture in Picture) til MOOC for elever Valg af arbejdsform: Mundtlig og visuel præsentation af grundlæggende faglige pointer Begrundelse for valg af materiale/medie/form/arbejdsform: Undersøgelse af, hvorvidt denne formidlingsform kan bruges...

  5. Rum og undervisningsformer

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2010-01-01

    Pædagogiske Universitetsskole, Aarhus Universitet (DPU‐AU), samt SBI (Aalborg Universitet). Kapitel 1 er skrevet af Jens Dolin og Sebastian Horst, begge IND. Dette kapitel tager afsæt i hvad der er karakteristisk for universitetsuddannelser og forsøger herudfra at udlede hvilke krav der må stilles til et godt...

  6. Martin Kok og Antinous

    DEFF Research Database (Denmark)

    Heede, Dag

    2018-01-01

    Præsentation af den glemte homoseksuelle forfatter Martin Kok med fokus på digtet "Antinous" og et arkivfund med en tidligere version.......Præsentation af den glemte homoseksuelle forfatter Martin Kok med fokus på digtet "Antinous" og et arkivfund med en tidligere version....

  7. Stress og Socialitet

    DEFF Research Database (Denmark)

    Strøbæk, Pernille Solveig

    2009-01-01

    Ifølge de etablerede arbejdsstressteorier skal miljømæssige krav balanceres op imod individuelle kontrolmuligheder, og der peges derfor på behovet for både sociologiske og psykologiske niveauer af arbejdsstress. Selvom en niveauinddelt tilgang til stress er vigtig, risikeres en opsplitning mellem...

  8. Tema og projekter

    DEFF Research Database (Denmark)

    Formålet med P2-projektenheden er at sætte de studerende i stand til på metodisk måde at gennemføre den problemorienterede og projektorganiserede læringsform i grupper, med tilhørende vurderinger af de opnåede resultater og en samlet konklusion....

  9. Digitalisering og HR

    DEFF Research Database (Denmark)

    Kühn Pedersen, Mogens

    2017-01-01

    Digitalisering står ligesom HR for et omfattende fag- og praksisfelt. Såvel praksis som teknologiudvikling styrer feltets stadige forandringer.......Digitalisering står ligesom HR for et omfattende fag- og praksisfelt. Såvel praksis som teknologiudvikling styrer feltets stadige forandringer....

  10. Mellem engagement og afmagt

    DEFF Research Database (Denmark)

    Ahrenkiel, Annegrethe; Nielsen, Birger Steen; Schmidt, Camilla

    Bogen præsenterer resultaterne fra udviklings- og forskningsprojektet "BUPL-tillidsrepræsentanten. Nye udfordringer - nye svar". Den giver et fyldigt indblik i tillidsrepræsentanternes arbejde, deres engagement, vanskeligheder og forhåbninger. På baggrund af et større værkstedsarbejde fremlægges...

  11. Gud og Darwin

    DEFF Research Database (Denmark)

    Hjermitslev, Hans Henrik

    2017-01-01

    Denne artikel nuancerer det synspunkt, at religion og evolution er nødvendige modsætninger, ved at vise, hvordan forholdet gennem historien frem til i dag er blevet tolket på mange forskellige måder, der spænder hele vejen fra ateistisk darwinisme, over teistisk evolution og kreationisme til fladj...

  12. Omsorg og etnicitet

    DEFF Research Database (Denmark)

    Rostgaard, Tine; Bjerre, Liv; Munkholt Sørensen, Kresta

    Flere nationale kampagner og initiativer har de senere år fokuseret på at få flere med anden etnisk baggrund end dansk til at arbejde i ældreplejen. Denne rapport afdækker, dels hvordan man bedst rekrutterer og ikke mindst fastholder medarbejdere med anden etnisk baggrund end dansk, dels hvilke k...

  13. Degas og New Orleans

    DEFF Research Database (Denmark)

    Indhold: Jean Sutherland Boggs: Edgar Degas og New Orleans. Marilyn R. Brown: Fransk-amerikanske aspekter af Degas' "Portrætter i et kontor, New Orleans". Katalog.......Indhold: Jean Sutherland Boggs: Edgar Degas og New Orleans. Marilyn R. Brown: Fransk-amerikanske aspekter af Degas' "Portrætter i et kontor, New Orleans". Katalog....

  14. Mediegenre, identifikation og reception

    Directory of Open Access Journals (Sweden)

    Kirsten Frandsen

    2005-09-01

    Full Text Available I artiklen sætter forfatterne fokus på forholdet mellem personer, der ser på personer i tv. Udgangspunktet er receptionsanalysen og den motiva- tion for tv-sening, der er forbundet med, at tv-seere relaterer sig til og identificerer sig med personer, der optræder på tv (tv-værter, medvir- kende osv.. Med afsæt i en funktionsorienteret definition af genrebe- grebet (forskellige genrer etablerer forskellige forventninger, indlevel- ser osv. hos modtageren gennemgår forfatterne forskellige teoretiske positioner, der hver især byder på forskellige forestillinger om forholdet (medie-tekst og modtageren. Det drejer sig om psykosemiotik,kogniti- onsteori, parasocial interaktionsteori, mikrosociologisk medieteori og spilteori, som alle har et mere eller mindre eksplicit bud på, hvordan medie og modtagere etablerer relationer som en central del af medie- brugerens motivationer og oplevelser. De forskellige teorier om identi- fikation danner ifølge forfatterne et kontinuum, spændende fra teorier om den stærke indlevelse til den mere overfladiske indlevelse. Forfat- terne advokerer for en mere nuanceret brug af begrebet identifikation, til forskel fra en generel brug af begrebet, som ikke medreflekterer de forskellige teoridannelsers forskellige syn på f.eks. magtforholdet mel- lem medie og modtager, og som derfor kan have store konsekvenser for analysens resultater.

  15. Samarbejdsformer og Facilities Management

    DEFF Research Database (Denmark)

    Storgaard, Kresten

    Resultater fra en surveyundersøgelse om fordele og ulemper ved forskellige samarbejdsformer indenfor Facilities Management fremlægges.......Resultater fra en surveyundersøgelse om fordele og ulemper ved forskellige samarbejdsformer indenfor Facilities Management fremlægges....

  16. Globalisering og forbrugerkultur

    DEFF Research Database (Denmark)

    2007-01-01

      "Globalisering og forbrugerkultur - over en kop kaffe" I denne podcast fortæller lektor Dannie Kjeldgaard (Institut for Marketing & Management) om resultaterne af sit forskningsprojekt om global forbrugerkultur og spredningen kaffebarkulturen. Han stiller spørgsmålstegn ved den gængse betragtning...

  17. Champagne og naiv dekadence

    DEFF Research Database (Denmark)

    Bjerre, Thomas Ærvold

    2007-01-01

    Portrætartikel om den amerikanske forfatter F. Scott Fitzgerald i anledningen af den danske udgivelse af De smukke og fortabte. Udgivelsesdato: 24. august......Portrætartikel om den amerikanske forfatter F. Scott Fitzgerald i anledningen af den danske udgivelse af De smukke og fortabte. Udgivelsesdato: 24. august...

  18. Mellem kontrol og afmagt

    DEFF Research Database (Denmark)

    Kjeldsen, Lena

    2015-01-01

    Sociale netværkssider som Facebook og Twitter er blevet en fast del af politikernes kommunikationsrepertoire, og således er journalister begyndt at monitorere platformene for nyhedsscoops, hvilket har skabt en ny kilde til den politiske journalistik: politikernes opdateringer. Formålet med...

  19. International fusion og spaltning

    DEFF Research Database (Denmark)

    Hansen, Lone L.

    Bogen analyserer de nye muligheder fra 2007 i europæisk ret med hensyn til fusion eller spaltning mellem aktieselskaber og anpartsselskaber med hjemsted i forskellige europæiske lande. Bogen gennemgår de nye muligheder for strukturændringer, der herved er opstået mulighed for, og den sætter fokus...

  20. Vico og barokkens retorik

    DEFF Research Database (Denmark)

    Catana, Leo

    filosofihistorie, æstetik, retorik Den italienske filosof Giambattista Vico (1668-1744) var barn af barokken, men led den uheldige skæbne at skulle tænke og gøre karriere i rationalismen og den moderne naturvidenskabs æra. Et fascinerende træk ved barokkens litterære retorik er dens polemiske dis...

  1. Sex, penge og jura

    DEFF Research Database (Denmark)

    Boisen, Jørn

    2011-01-01

    skulle ændres, da de sendte sexarbejderne under jorden og i armene på mafiaen. Den lovgivning, der blev kendt ugyldig i Ontario, minder meget om den danske, vurderer Jørn Boisen. Han kalder modellen for den repressive, da det er den mest paradoksale og hykleriske model. Den har nemlig til hensigt...

  2. Minnismentan og list

    DEFF Research Database (Denmark)

    Simonsen, Kim

    2011-01-01

    the latest times, we have seen many new statues of Tróndur and Sigmundur from the Faroe Saga. Famous industrialist's and a new hook in Klaksvík, to remind us of the fishing with long lines. Article in relation to the seminar 'Millum Kongaminni og Kitsh' (Mellem KOngemindet og kitch), held at the Nordic House...

  3. Culpa og god revisorskik

    DEFF Research Database (Denmark)

    Langsted, Lars Bo

    1995-01-01

    Artiklen fremhæver, at der ikke er automatisk sammenfald mellem responsumudvalgets vurdering af god revisorskik og domstolenes anvendelse af culpa-begrebet i teorien men nok i praksis.......Artiklen fremhæver, at der ikke er automatisk sammenfald mellem responsumudvalgets vurdering af god revisorskik og domstolenes anvendelse af culpa-begrebet i teorien men nok i praksis....

  4. Informationskompetence og it

    DEFF Research Database (Denmark)

    Christensen, Poul Henning

    2004-01-01

    I artiklen sætter jeg fokus på informationskompetencebegrebet og hvordan der, med udviklingen indenfor informationsteknologien og de globale digitale netværk, synes at være føjet mange nye dimensioner til kompetencen....

  5. Receptive processer og IT

    DEFF Research Database (Denmark)

    Ambjørn, Lone

    2002-01-01

    Sproglæringsteoretisk værktøj til udvikling af IT-støttede materialer og programmer inden for sproglig reception......Sproglæringsteoretisk værktøj til udvikling af IT-støttede materialer og programmer inden for sproglig reception...

  6. It og udvikling

    DEFF Research Database (Denmark)

    Hachmann, Roland; Carlsen, Dorthe

    2013-01-01

    Artiklen sætter fokus på fagteamets arbejde med at udvikle fagene med fokus på it og digitale læremidler. Der gives, gennem konkrete modeller og værktøjer, eksempler på hvordan fagteamet kan gøre en indsats i forhold til deres nuværende praksis....

  7. Personlig kommunikation og IT

    DEFF Research Database (Denmark)

    Ambjørn, Lone

    Materialet er udviklet specielt til faget 'Personlig kommunikation og IT' på 4. sem. BA, spansk. Det er udviklet på basis af forskning inden for netværksstøttet sproglig læring. Undervisningen tilrettelægges i et differentieret perspektiv, hvilket bl.a. arbejde med web-baserede materialer og...

  8. Mellem deltagelse og publikumsudvikling

    DEFF Research Database (Denmark)

    Bjørnsen, Egil; Hansen, Louise Ejgod; Vatne, Ingrid

    2015-01-01

    Aarhus 2017 (Aarhus som europæisk kulturhovedstad). Vi undersøger, hvor-dan de positionerer sig i feltet mellem den brede deltagelsesdiskurs og den snævre publikumsudviklingsdiskurs ved at se på tre forskellige dimensioner: produkt- vs. modtagerorientering, holdnings- vs. handlingsændring og empowerment...

  9. Eventyrerne og de strandede

    DEFF Research Database (Denmark)

    Jacobsen, Peter

    magasinet som værdiskabende. Af forskellige artikeltyper i magasinet foretrak testpersonerne den klassiske magasinartikel suppleret med fotogallerier, video og pop-op-tekster. Det stod dog klart, at mange brugere har svært ved at finde rundt i et digitalt magasin. Navigations-signalerne bør være klare og...

  10. Om performance og oplevelsesanalyse

    DEFF Research Database (Denmark)

    Nagbøl, Søren Peter; Flensborg, Ingelise

    2016-01-01

    , teori og praksis kan gennemføres i oplevelsesorienterede processer, hvor performance, sanselig praksis, transformeres til ting, sprog og billeder. Med afsæt i en konkret skulptur, Auguste Rodins (1840-1917) "Borgerne fra Calais", som er udstillet på Ny Carlsberg Glyptotek i København, giver vi eksempler...

  11. Mig og Judith Butler

    DEFF Research Database (Denmark)

    Heede, Dag

    2015-01-01

    Essay om forfatterens akademiske og personlige møde med Judith Butler i temanummer i forbindelse med 25 års jubilæum for udgivelsen af Gender Trouble (1990).......Essay om forfatterens akademiske og personlige møde med Judith Butler i temanummer i forbindelse med 25 års jubilæum for udgivelsen af Gender Trouble (1990)....

  12. Billeder og viden

    DEFF Research Database (Denmark)

    Dam Christensen, Hans

    2011-01-01

    Artiklen gentænker og problematiserer en række af de forestillinger, der hyppigt knyttes til billeder og visuelle medier. Det sker med henblik på at åbne for en mere nuanceret forståelse af billeders betydning for brug af vidensmediering såvel som billeders funktion som vidensmedier. To væsentlig...

  13. Om religion og evolution

    DEFF Research Database (Denmark)

    Geertz, Armin W.

    2011-01-01

    for kulturens kausale virkning på den menneskelige kognition og ikke mindst den hominine evolution. Ud fra, hvad vi ved om den menneskelige evolution, ses det, at den hominine evolution har en dybde, som sjældent medtænkes i teorier og hypoteser om den menneskelige evolution. Den menneskelige evolution er...

  14. Praksisudvikling og respektproduktion

    DEFF Research Database (Denmark)

    Mørck, Line Lerche; Elholm, Nynne; Jensen, Silla

    2012-01-01

    Dette kapitel har form som en casebaseret refleksion over arbejdet med praksisudvikling og respektproduktion på en produktionsskolelinje kaldet Kulturcoach, samt teori udvikling og empiribaseret diskussion af anerkendelses-processer forstået som positiv interpellation. Danmark har 79 produktionss...

  15. Sport og medierettigheder

    DEFF Research Database (Denmark)

    Jakobsen, Søren Sandfeld

    2014-01-01

    Kapitlet behandler en række medie-, immaterial- og konkurrenceretlige aspekter ved overdragelse af tv-rettigheder til store sportsbegivenheder.......Kapitlet behandler en række medie-, immaterial- og konkurrenceretlige aspekter ved overdragelse af tv-rettigheder til store sportsbegivenheder....

  16. Kollegialitet og teamwork

    DEFF Research Database (Denmark)

    Bovbjerg, Kirsten Marie; Søgaard Sørensen, Marianne

    2007-01-01

     Kapitlet beskæftiger sig med teamwork som en af de sociale teknologier, der i dag, også indenfor undervisningssektoren, er med til at forandre medarbejderes, og altså her læreres, forståelse af deres arbejdsliv. Ud fra empiriske studier på erhvervsskoleområdet kontrasteres team-samarbejde med de...

  17. Klasseledelse, inklusion og differentiering

    DEFF Research Database (Denmark)

    Jørgensen, Christina; Mottelson, Martha

    2014-01-01

    Kapitlet behandler forholdet mellem de tre begreber klasseledelse, inklusion og differentiering og ser på, hvordan de folder sig ud i folkeskolens praksis. Der tages afsæt i en definition af klasseledelse som alle de redskaber, læreren tager i anvendelse med henblik på at få timen til tage form p...

  18. Foto og dokumentation

    DEFF Research Database (Denmark)

    Rasmussen, Kim

    2011-01-01

    Et kapitel der giver eksempler på hvordan fotografi anvendes som en form for dokumentation i pædagogisk arbejde, samtidig med at kapitlet kaster et kritisk lys over hvad der menes med dokumentation og hvorvidt fotografi kan dokumentere pædagogisk arbejde og institutionsliv...

  19. Arkitektur og dannelse

    DEFF Research Database (Denmark)

    Knudsen, Lars Emmerik Damgaard

    2017-01-01

    (Biesta: 1999, 2009 og Wood (interview med Biesta): 2015).Jeg vil i dette kapitel tage udgangspunkt i Biestas egne eksempler på konkrete udtryk for de mundane rum og arkitektens muligheder for at skabe disse. Ved at lave en analyse af hans dannelsesbegreb kritiserer jeg begrebet mundane rum for at overse...

  20. Klasse, kultur og politik

    DEFF Research Database (Denmark)

    Skjøtt-Larsen, Jakob

    Med udgangspunkt i den den franske sociolog Pierre Bourdieus arbejde, særligt La Distinktion (1979), undersøges nutidige mønstre for social differentiering i Aalborg. En større spørgeskemaundersøgelse og 16 dybdegående interviews inddrages i en analyse af sammenhænge mellem ulighed, identitet og ...

  1. Ford og fordismen

    DEFF Research Database (Denmark)

    Wagner, Michael

    2010-01-01

    Stort set alle politiske retninger, fra kommunisme til fascisme, såvel som demokratiske samfund, var tiltrukket af fordismen i teori og praksis.s......Stort set alle politiske retninger, fra kommunisme til fascisme, såvel som demokratiske samfund, var tiltrukket af fordismen i teori og praksis.s...

  2. Hypotakse og indlejring

    DEFF Research Database (Denmark)

    Holsting, Alexandra Emilie Møller

    2007-01-01

    I artiklen foretager jeg en diskussion af kategorierne sætningskompleks og indlejret sætning inden for systemisk funktionel lingvistik (SFL). Problemet med den systemisk funktionelle beskrivelse er at den ikke formår at gøre rede for grammatiske forskelle på forskellige typer bisætninger, og jeg...

  3. Globalisering og nationalisme

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2015-01-01

    På universitetet underviser jeg – sammen med gode kolleger – i et kursus om fænomenerne globalisering og transnationalisme. Jeg har gjort det nogle år nu, og en af de ting, som jeg synes er påfaldende hver gang er, at jeg kommer til at tale meget om nationalstaten. Det bliver brugt rigtigt meget...

  4. Betonkrav og praksis

    DEFF Research Database (Denmark)

    Poulsen, E.

    Publikationen giver en historisk gennemgang af danske betonkrav, dansk projektering- og udførelsespraksis samt eksisterende viden om betons holdbarhed. Stoffet er belyst med eksempler fra skadesager, og det beskrives, hvordan holdbarhedskrav er blevet opfattet på forskellige tidsspunkter....

  5. Hjernen og psyken

    DEFF Research Database (Denmark)

    Gerlach, Christian; Starrfelt, Randi

    2007-01-01

    Klassisk og moderne psykologisk teori er en indføring i psykologiens centrale teorier, personer, temaer og begreber. Bogens første del er en kronologisk gennemgang af psykologiens udvikling fra 1879, hvor Wilhelm Wundt etablerede det første psykologiske laboratorium, til nutidens dominerende...

  6. Krise, kritik og samtidsdiagnostik

    DEFF Research Database (Denmark)

    Kristensen, Jens Erik

    2008-01-01

    sjældent de teoretiske, analytiske og retoriske implikationer af diagnoseperspektivet alvorligt. Af samme grund bemærker man heller ikke farerne ved en ureflekteret og metaforisk omgang med diagnose-termen, f.eks. den at man uforvarende kommer til at forskrive sig til den medicinske diskurs' dualismer...

  7. Feedback og interpersonel kommunikation

    DEFF Research Database (Denmark)

    Dindler, Camilla

    2016-01-01

    Som interpersonel kommunikationsform handler feedback om at observere, mærke og italesætte det, som handler om relationen mellem samtaleparterne mere end om samtaleemnet. Her er fokus på, hvad der siges og hvordan der kommunikeres sammen. Feedback er her ikke en korrigerende tilbagemelding til...

  8. Lys, lyspunkter og lyseslukkere

    DEFF Research Database (Denmark)

    Larsen, Lene Gerd

    2001-01-01

    De historiske bykvarterer fremviser hver deres lokalpræg og egenart, som det er væsentligt at fastholde, men det er samtidig vigtigt, at man ikke overromantiserer og idylliserer det historiske miljø. Omvendt synes trangen til selvhævdelse, til at bruge omgivelserne som trampolin for et egocentrisk...

  9. Nedbrud og Omstilling

    DEFF Research Database (Denmark)

    Madsen, Erik Skov; Riis, Jens Ove; Sørensen, Brian Vejrum

    2007-01-01

    , markedsinformation og kapabiliteter, som er lokalt forankret i virksomhedens globale produktionsnetværk. Grundet skift i den globale arbejdsdeling og behovet for at opsøge nye muligheder, investeres der store summer i den globale rekonfigurering af virksomhedernes produktionsnetværk, hvilket skaber behovet...

  10. Religion, hukommelse og viden

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2008-01-01

    til en understregning af hukommelsen som et essentielt tema i en generel religionsteori. Artiklen diskuterer Assmanns brug af Maurice Halbwachs og foreslår at se Assmanns teori som en reformulering af indsigter, der går tilbage til Emile Durkheim og som genfindes i fx Roy A. Rappaports ritualteori...

  11. Godsejer og reformator

    DEFF Research Database (Denmark)

    Rasmussen, Carsten Porskrog

    2010-01-01

    Artiklen handler om A.G. Moltke som godsejer. Den beskæftiger sig med opbygningen og forvaltningen af hans godsimperium. Videre omhandles forholdet til bønderne og godsejerens feudalt-patriarkalske rolle. Endelig skildres Moltkes store betydning for de tidlige landboreformer....

  12. Musik, Sprog og Integration

    DEFF Research Database (Denmark)

    Holst, Finn

    2010-01-01

    Evaluering af projektet Musik, Sprog og Integration, Søndermarkskolen, Horsens. Andenårsevaluering af et treårigt projekt.......Evaluering af projektet Musik, Sprog og Integration, Søndermarkskolen, Horsens. Andenårsevaluering af et treårigt projekt....

  13. Caries og drikkevandets kvalitet

    DEFF Research Database (Denmark)

    Arvin, Erik; Bardow, Allan; Bruvo, Maja

    2011-01-01

    Drikkevandskvaliteten har stor betydning for forekomsten af caries blandt 15 årige skolebørn, også selv om de bruger fluoridholdigt tandpasta. Ud over den kendte effekt af fluorid har vi vist, at calcium også har en væsentlig betydning. Begge ioner forebygger caries. Denne viden har væsentlig...

  14. Probiotika og caries

    DEFF Research Database (Denmark)

    Keller, Mette Kirstine

    2017-01-01

    Nærværende artikel præsenterer en oversigt over den foreliggende viden om kostens betydning for diabetes mellitus (DM) og parodontal inflammation. Der er i vekslende grad dokumentation for sammenhænge mellem kost, DM og marginal parodontitis (MP). Med baggrund i forøget viden om kostens betydning...

  15. Sukker og caries

    DEFF Research Database (Denmark)

    Twetman, Svante

    2017-01-01

    Nærværende artikel præsenterer en oversigt over den foreliggende viden om kostens betydning for diabetes mellitus (DM) og parodontal inflammation. Der er i vekslende grad dokumentation for sammenhænge mellem kost, DM og marginal parodontitis (MP). Med baggrund i forøget viden om kostens betydning...

  16. Unge, sundhed og fitness

    DEFF Research Database (Denmark)

    Jensen, Jens-Ole

    2003-01-01

    Artiklen redegør for udbredelsen af fitness blandt unge og diskuterer, hvor det er blevet så populært at dyrke fitness.......Artiklen redegør for udbredelsen af fitness blandt unge og diskuterer, hvor det er blevet så populært at dyrke fitness....

  17. The physical basis of bacterial quorum communication

    CERN Document Server

    2015-01-01

    This book aims to educate physical scientists and quantitatively-oriented biologists on the application of physical experimentation and analysis, together with appropriate modeling, to understanding and interpreting microbial chemical communication and especially quorum sensing (QS). Quorum sensing describes a chemical communication behavior that is nearly universal among bacteria. Individual cells release a diffusible small molecule (an autoinducer) into their environment. A high concentration of this autoinducer serves as a signal of high population density, triggering new patterns of gene expression throughout the population. However QS is often much more complex than simple census-taking. Many QS bacteria produce and detect multiple autoinducers, which generate quorum signal cross talk with each other and with other bacterial species. QS gene regulatory networks operate in physically complex environments and respond to a range of inputs in addition to autoinducer signals. While many individual QS systems ...

  18. The Effect of Novel Heterocyclic Compounds on Cryptococcal Biofilm

    Science.gov (United States)

    Korem, Maya; Kagan, Sarah

    2017-01-01

    Biofilm formation by microorganisms depends on their communication by quorum sensing, which is mediated by small diffusible signaling molecules that accumulate in the extracellular environment. During human infection, the pathogenic yeast Cryptococcus neoformans can form biofilm on medical devices, which protects the organism and increases its resistance to antifungal agents. The aim of this study was to test two novel heterocyclic compounds, S-8 (thiazolidinedione derivative, TZD) and NA-8 (succinimide derivative, SI), for their anti-biofilm activity against strains of Cryptococcus neoformans and Cryptococcus gattii. Biofilms were formed in a defined medium in 96-well polystyrene plates and 8-well micro-slides. The effect of sub-inhibitory concentrations of S-8 and NA-8 on biofilm formation was measured after 48 h by a metabolic reduction assay and by confocal laser microscopy analysis using fluorescent staining. The formation and development of cryptococcal biofilms was inhibited significantly by these compounds in concentrations below the minimum inhibitory concentration (MIC) values. These compounds may have a potential role in preventing fungal biofilm development on indwelling medical devices or even as a therapeutic measure after the establishment of biofilm. PMID:29371559

  19. Medieetnografi og kvalitativ metode

    Directory of Open Access Journals (Sweden)

    Tove Arendt Rasmussen

    1993-09-01

    Full Text Available Udviklingen af et metodisk fællesskab mellem samfundsvidenskab og humaniora op gennem 80´erne har haft gode vækstbetingelser inden for medieetnografien. Artiklen gennemgår i hovedtræk den prægnan- te udvikling modtagerforskningen med rod i humaniora og cultural studies-traditionen har gennemgået. Hvor den tidligere var funderet i interessen for at afdække sammenhænge mellem medieindhold og seeroplevelse, har medieetnografien udviklet en sensibilitet over for TV-sening som en mangfoldig, kulturel proces. Artiklens tyngdepunkt ligger i en diskussion af de metodiske problemer, forskeren konfron- teres med, når mangfoldigheden af tekstuelle, situationelle og kontek- stuelle perspektiver på receptionsproces og betydningsdannelse på én gang inddrages i de medieetnografiske studier.

  20. Nyhedsmedielogik og krisediplomati

    DEFF Research Database (Denmark)

    Ørsten, Mark

    2016-01-01

    Tidligere forskning i massemedier og diplomati har peget i mange forskellige retninger, men især forsøgt at undersøge, hvordan nyhedsmedier har været med til at præge den offentlige meningsdannelse i forhold til vigtige emner i både indland og udland. Med udgangspunkt i moderne medialiseringsteori...... fokuserer denne artikel på, hvordan samfundets institutioner bliver påvirket af nyhedsmedierne og deres logikker, og helt specifikt hvordan denne udvikling påvirker to af de forskellige typer af krisediplomati, der er i fokus i dette temanummer: Krisediplomati forstået som ’diplomati i krise’ og...

  1. Kognitiv kapacitet og bevidsthed

    DEFF Research Database (Denmark)

    Nielsen, Cathrine Sand; Sørensen, Birgitte

    2012-01-01

    Kognitiv kapacitet handler om vores brug af hjernen. Langt hovedparten af menneskets brug af hjernen foregår ubevidst. Vi gør det allerede indlærte automatisk uden at tænke over det. Samtidig er den kognitive kapacitet meget følsom, og mange faktorer kan påvirke evnen til at indoptage, bearbejde og...... planlægges en sygepleje, der bedst sikrer patientens mulighed for at deltage i plejen under hensyntagen til den påvirkede kognitive kapacitet. Væsentlige faktorer, der påvirker kognitiv kapacitet og bevidsthed, præsenteres. Til slut gives der eksempler på sygeplejeinterventioner. I kapitlet eksemplificeres...... begreberne om kognitiv kapacitet og bevidsthed, observationer og handlinger løbende i en case om Erna Svendsen....

  2. Befolkningsimplosion og seniorpolitik

    DEFF Research Database (Denmark)

    Bøye, Erik Møllmann; Bøye, Solveig

    2000-01-01

    Denne artikel vil først belyse baggrunden for at tale om et globalt aldersskælv eller alderdommedag og om en befolkningsimplosion - på et tidspunkt, hvor kurven for Jordens folketal næsten er lodret stigende. Derefter rettes blikket mod Danmark. De globale tendenser, lav-fertiltet og stigende...... levealder, gør sig også gældende her i landet. Sammen med den befolkningsudskiftning, der følger af retten til familiesammenføring, vil det i løbet af få år fuldstændig forandre befolkningsstrukturen her i landet. Og det diskuteres, hvilken betydning dette vil have for seniorpolitikken i de private og...

  3. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

  4. Quorum Sensing Regulation in Aeromonas hydrophila

    DEFF Research Database (Denmark)

    Garde, Christian; Bjarnsholt, Thomas; Givskov, Michael

    2010-01-01

    We present detailed results on the C4-HSL-mediated quorum sensing (QS) regulatory system of the opportunistic Gram-negative bacterium Aeromonas hydrophila. This bacterium contains a particularly simple QS system that allows for a detailed modeling of kinetics. In a model system (i.e., the Escheri......We present detailed results on the C4-HSL-mediated quorum sensing (QS) regulatory system of the opportunistic Gram-negative bacterium Aeromonas hydrophila. This bacterium contains a particularly simple QS system that allows for a detailed modeling of kinetics. In a model system (i...

  5. Jern og zink i cerealier

    DEFF Research Database (Denmark)

    Persson, Daniel Olof; Hansen, Thomas Hesselhøj; Thomsen, Rikke Pape

    2009-01-01

    Mangel på mikronæringsstoffer, især jern og zink, er et udbredt og voksende problem for mennesker i mange udviklingslande. Det skyldes, at cerealer som ris og hvede udgør den dominerende fødekilde. Konsekvensen er en række negative indvirkninger på menneskers sundhed, udvikling, arbejdsevne og...

  6. Marked og produkter i Kenya

    DEFF Research Database (Denmark)

    Roos, Nanna

    2014-01-01

    Et forskningsprojekt med dansk deltagelse undersøger, hvordan masseproduktion af insekter kan etableres i Kenya og bidrage med fødevarer til mennesker og protein til husdyrfoder.......Et forskningsprojekt med dansk deltagelse undersøger, hvordan masseproduktion af insekter kan etableres i Kenya og bidrage med fødevarer til mennesker og protein til husdyrfoder....

  7. Om vrede og negativ universalisme

    DEFF Research Database (Denmark)

    Rösing, Lilian Munk

    2009-01-01

    Kan vreden betragtes som en kreativ drivkraft, både politisk, æstetisk og eksistentielt? Og i så fald, er det den samme vrede der er virksom i politikken, kunsten og eksistensen? Disse spørgsmål diskuteres med udgangspunkt i Slavoj Zizeks Violence og Peter Sloterdijks Sein und Zeit Udgivelsesdato...

  8. Medier – love og regler

    DEFF Research Database (Denmark)

    Jørgensen, Oluf

    Den mest komplette samling af de love og regler, der har størst betydning for medier og journalistik i Danmark. Samlingen ajourføres, når Folketinget lukker i juni, og alle nye bestemmelser dermed er kendt. Nyt i udgaven 2013-2014 er blandt andet den nye offentlighedslov. Og så er der ændringer i...

  9. Følelse og fornuft

    DEFF Research Database (Denmark)

    Busk, Malene

    2007-01-01

    supplerer reelt hinanden, mens det nedbryder og modarbejder udviklingen af konstruktive former for følelse og fornuft: Tro kræver at fornuften tier og kynismen kræver at følsomheden afstumpes. En af epokens udfordringer er netop at gendefinere følelse og fornuft så begreberne ikke indebærer den systematiske...

  10. Lean og arbejdsmiljø

    DEFF Research Database (Denmark)

    Jensen, Kenneth

    Bogen tager udgangspunkt i en undersøgelse af 10 private og offentlige virksomheders erfaringer med lean. Undersøgelsen viser at der ikke findes entydige sammenhænge mellem lean og det psykosociale arbejdsmiljø. Bogen forholder sig til sammenhængen mellem lean og ledelse, lean og medarbejderens...... rolle, lean og lean og forandringsprocessen. Bogen kommer desuden med anbefalinger til hvorledes virksomheden kan gribe dialogen an for at opnå et godt lean forløb der inddrager hensynet til og effekterne af et godt psykosocialt arbejdsmiljø....

  11. QStatin, a Selective Inhibitor of Quorum Sensing in Vibrio Species

    Directory of Open Access Journals (Sweden)

    Byoung Sik Kim

    2018-01-01

    Full Text Available Pathogenic Vibrio species cause diseases in diverse marine animals reared in aquaculture. Since their pathogenesis, persistence, and survival in marine environments are regulated by quorum sensing (QS, QS interference has attracted attention as a means to control these bacteria in aquatic settings. A few QS inhibitors of Vibrio species have been reported, but detailed molecular mechanisms are lacking. Here, we identified a novel, potent, and selective Vibrio QS inhibitor, named QStatin [1-(5-bromothiophene-2-sulfonyl-1H-pyrazole], which affects Vibrio harveyi LuxR homologues, the well-conserved master transcriptional regulators for QS in Vibrio species. Crystallographic and biochemical analyses showed that QStatin binds tightly to a putative ligand-binding pocket in SmcR, the LuxR homologue in V. vulnificus, and changes the flexibility of the protein, thereby altering its transcription regulatory activity. Transcriptome analysis revealed that QStatin results in SmcR dysfunction, affecting the expression of SmcR regulon required for virulence, motility/chemotaxis, and biofilm dynamics. Notably, QStatin attenuated representative QS-regulated phenotypes in various Vibrio species, including virulence against the brine shrimp (Artemia franciscana. Together, these results provide molecular insights into the mechanism of action of an effective, sustainable QS inhibitor that is less susceptible to resistance than other antimicrobial agents and useful in controlling the virulence of Vibrio species in aquacultures.

  12. Radon og boligen

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    Radon er en radioaktiv og sundhedsskadelig luftart, som ved indånding øger risikoen for lungekræft. Der er ingen dokumenteret nedre grænse for, hvornår radon er ufarligt. Derfor anbefales det, at man tilstræber et så lavt radonindhold i indeluften som muligt. Man kan hverken lugte, se, høre eller...... smage radon, så vil du vide, om du har radon i din bolig, må du måle radonindholdet i indeluften. Radon forekommer naturligt i jorden og kan suges ind sammen med jordluft, hvis der inde er et undertryk, og hvis konstruktionerne mod jord er utætte. Jordluft trænger ind gennem revner og utætte samlinger......, fx omkring rør til kloak, vand og varmeforsyning. Koncentrationen af radon i jorden varierer meget fra sted til sted, også lokalt og gennem året. Tidligere undersøgelser har vist, at der kan forekomme høje koncentrationer i Sydgrønland, specielt i området syd for Narsalik ved Paamiut, 61°30’N....

  13. Ford og fordismen

    DEFF Research Database (Denmark)

    Wagner, Michael

    Fordismen var et epokegørende, nybrydende og vidtspændende globalt fænomen, som opstod i begyndelsen af det 20. århundrede. I sit udspring byggede ophavsmanden til fordismen, automobilkongen Henry Ford, på et utroligt solidt, billigt og driftsikkert produkt, nemlig automobilet Ford Model T....... Fordismen udvikler en helt ny industriel produktionsmåde beregnet til masseproduktion af varige forbrugsgoder og en samfundsfilosofi. Fordismens epoke skabte en helt ny økonomisk teori om massekonsumets betydning i samfundet. Henry Ford dikterede på grundlag af sin store og iøjnefaldende succes en totalitær...... fra 1908, hvor produktionen af Ford Model T blev indledt, og frem til efteråret 1929, da børsen i Wall Street krakkede og trak hele verdensøkonomien ind i en dyb og langvarig krise. Produktionen af Ford Model T var blevet indstillet to år forinden; da havde man rundet et antal på 15 millioner...

  14. Biofilm Development

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2015-01-01

    During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction or terminat......During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction...... or termination of biofilm matrix production via the second messenger molecule c-di-GMP. In between initiation and termination of biofilm formation we have defined specific biofilm stages, but the currently available evidence suggests that these transitions are mainly governed by adaptive responses......, and not by specific genetic programs. It appears that biofilm formation can occur through multiple pathways and that the spatial structure of the biofilms is species dependent as well as dependent on environmental conditions. Bacterial subpopulations, e.g., motile and nonmotile subpopulations, can develop...

  15. Relative contributions of Vibrio polysaccharide and quorum sensing to the resistance of Vibrio cholerae to predation by heterotrophic protists.

    Directory of Open Access Journals (Sweden)

    Shuyang Sun

    Full Text Available Protozoan grazing is a major mortality factor faced by bacteria in the environment. Vibrio cholerae, the causative agent of the disease cholera, is a natural inhabitant of aquatic ecosystems, and its survival depends on its ability to respond to stresses, such as predation by heterotrophic protists. Previous results show that grazing pressure induces biofilm formation and enhances a smooth to rugose morphotypic shift, due to increased expression of Vibrio polysaccharide (VPS. In addition to negatively controlling vps genes, the global quorum sensing (QS regulator, HapR, plays a role in grazing resistance as the ΔhapR strain is efficiently consumed while the wild type (WT is not. Here, the relative and combined contributions of VPS and QS to grazing resistance were investigated by exposing VPS and HapR mutants and double mutants in VPS and HapR encoding genes at different phases of biofilm development to amoeboid and flagellate grazers. Data show that the WT biofilms were grazing resistant, the VPS mutants were less resistant than the WT strain, but more resistant than the QS mutant strain, and that QS contributes to grazing resistance mainly in mature biofilms. In addition, grazing effects on biofilms of mixed WT and QS mutant strains were investigated. The competitive fitness of each strain in mixed biofilms was determined by CFU and microscopy. Data show that protozoa selectively grazed the QS mutant in mixed biofilms, resulting in changes in the composition of the mixed community. A small proportion of QS mutant cells which comprised 4% of the mixed biofilm biovolume were embedded in grazing resistant WT microcolonies and shielded from predation, indicating the existence of associational protection in mixed biofilms.

  16. Long-Chain 4-Aminoquinolines as Quorum Sensing Inhibitors in Serratia marcescens and Pseudomonas aeruginosa.

    Science.gov (United States)

    Aleksić, Ivana; Šegan, Sandra; Andrić, Filip; Zlatović, Mario; Moric, Ivana; Opsenica, Dejan M; Senerovic, Lidija

    2017-05-19

    Antibiotic resistance has become a serious global threat to public health; therefore, improved strategies and structurally novel antimicrobials are urgently needed to combat infectious diseases. Here we report a new type of highly potent 4-aminoquinoline derivatives as quorum sensing inhibitors in Serratia marcescens and Pseudomonas aeruginosa, exhibiting weak bactericidal activities (minimum inhibitory concentration (MIC) > 400 μM). Through detailed structure-activity study, we have identified 7-Cl and 7-CF 3 substituted N-dodecylamino-4-aminoquinolines (5 and 10) as biofilm formation inhibitors with 50% biofilm inhibition at 69 μM and 63 μM in S. marcescens and P. aeruginosa, respectively. These two compounds, 5 and 10, are the first quinoline derivatives with anti-biofilm formation activity reported in S. marcescens. Quantitative structure-activity relationship (QSAR) analysis identified structural descriptors such as Wiener indices, hyper-distance-path index (HDPI), mean topological charge (MTC), topological charge index (TCI), and log D(o/w) exp as the most influential in biofilm inhibition in this bacterial species. Derivative 10 is one of the most potent quinoline type inhibitors of pyocyanin production described so far (IC 50 = 2.5 μM). While we have demonstrated that 5 and 10 act as Pseudomonas quinolone system (PQS) antagonists, the mechanism of inhibition of S. marcescens biofilm formation with these compounds remains open since signaling similar to P. aeruginosa PQS system has not yet been described in Serratia and activity of these compounds on acylhomoserine lactone (AHL) signaling has not been detected. Our data show that 7-Cl and 7-CF 3 substituted N-dodecylamino-4-aminoquinolines present the promising scaffolds for developing antivirulence and anti-biofilm formation agents against multidrug-resistant bacterial species.

  17. Teknologi og callcentre - mellem masseproduktion og service

    DEFF Research Database (Denmark)

    Sørensen, Ole H.

    2007-01-01

    Artiklen diskuterer, på hvilken måde callcenter teknologier påvirker kvaliteten af arbejdet. Artiklen fokuserer specielt på, hvordan mulighederne for at relokalisere opkald internt i callcentre, til underleverandører og til/fra udlandet forøger arbejdsgivernes kontrol over arbejdsprocessen...

  18. Gadekunst og gentrificering

    DEFF Research Database (Denmark)

    Samson, Kristine

    2011-01-01

    Inden for byudvikling er der på det seneste sket et paradigmeskifte fra den funktionalistiske planlægning mod performative og processuelle praksisser. PÅ denne udvidede byudviklingscene spiller den urbane kunst en væsentlig rolle. Street arten har aldrig tilhørt kulturinstitutionernes white cubes....... I stedet markerer street art et urbant territorier og kan pege frem mod fremtidige potentialer og udviklingsmuligheder. Artiklen argumenterer for, at street art kan ses som en performativ æstetik, der peger på et områdes igangværende gentrificeringsproces....

  19. Leg og dannelse

    DEFF Research Database (Denmark)

    Skovbjerg, Helle Marie

    2017-01-01

    lederen i det pædagogiske tidskrift Asterisk: ”Leg i skolen, leg i klasserummet, ja legende læring i skolen udgør derimod en enorm, seriøs og ubrugt læringsressource – ikke alene med effekter på kreativiteten, men også på den faglige læring” (Holm, 2015, p. 2). Legens værdi gøres altså først og fremmest...

  20. Depresjon og kognitiv terapi

    OpenAIRE

    Blåfjelldal, Ida; Severinsen, Monica

    2008-01-01

    Kognitiv terapi er en form for psykoterapi, som tar sikte på behandlingen av psykiske lidelser. Vi har valgt å fokusere på behandlingen av deprimerte pasienter. Vi bruker enkle modeller og skjemaer for å belyse vår problemstilling, og forteller om kognitiv terapi. Vi viser hvordan pasienter kan ta i bruk et skjema som skal være til hjelp for å mestre en vanskelig situasjon. For å belyse dette tema har vi valgt å bruke sykepleieteoretikerne Watson og Orlando, som belyser ulike sider ved vårt t...

  1. Nutrient transitions are a source of persisters in Escherichia coli biofilms.

    Directory of Open Access Journals (Sweden)

    Stephanie M Amato

    Full Text Available Chronic and recurrent infections have been attributed to persisters in biofilms, and despite this importance, the mechanisms of persister formation in biofilms remain unclear. The plethora of biofilm characteristics that could give rise to persisters, including slower growth, quorum signaling, oxidative stress, and nutrient heterogeneity, have complicated efforts to delineate formation pathways that generate persisters during biofilm development. Here we sought to specifically determine whether nutrient transitions, which are a common metabolic stress encountered within surface-attached communities, stimulate persister formation in biofilms and if so, to then identify the pathway. To accomplish this, we established an experimental methodology where nutrient availability to biofilm cells could be controlled exogenously, and then used that method to discover that diauxic carbon source transitions stimulated persister formation in Escherichia coli biofilms. Previously, we found that carbon source transitions stimulate persister formation in planktonic E. coli cultures, through a pathway that involved ppGpp and nucleoid-associated proteins, and therefore, tested the functionality of that pathway in biofilms. Biofilm persister formation was also found to be dependent on ppGpp and nucleoid-associated proteins, but the importance of specific proteins and enzymes between biofilm and planktonic lifestyles was significantly different. Data presented here support the increasingly appreciated role of ppGpp as a central mediator of bacterial persistence and demonstrate that nutrient transitions can be a source of persisters in biofilms.

  2. Nutrient transitions are a source of persisters in Escherichia coli biofilms.

    Science.gov (United States)

    Amato, Stephanie M; Brynildsen, Mark P

    2014-01-01

    Chronic and recurrent infections have been attributed to persisters in biofilms, and despite this importance, the mechanisms of persister formation in biofilms remain unclear. The plethora of biofilm characteristics that could give rise to persisters, including slower growth, quorum signaling, oxidative stress, and nutrient heterogeneity, have complicated efforts to delineate formation pathways that generate persisters during biofilm development. Here we sought to specifically determine whether nutrient transitions, which are a common metabolic stress encountered within surface-attached communities, stimulate persister formation in biofilms and if so, to then identify the pathway. To accomplish this, we established an experimental methodology where nutrient availability to biofilm cells could be controlled exogenously, and then used that method to discover that diauxic carbon source transitions stimulated persister formation in Escherichia coli biofilms. Previously, we found that carbon source transitions stimulate persister formation in planktonic E. coli cultures, through a pathway that involved ppGpp and nucleoid-associated proteins, and therefore, tested the functionality of that pathway in biofilms. Biofilm persister formation was also found to be dependent on ppGpp and nucleoid-associated proteins, but the importance of specific proteins and enzymes between biofilm and planktonic lifestyles was significantly different. Data presented here support the increasingly appreciated role of ppGpp as a central mediator of bacterial persistence and demonstrate that nutrient transitions can be a source of persisters in biofilms.

  3. Towards rational design of redox-stratified biofilms

    DEFF Research Database (Denmark)

    Lackner, Susanne

    Biologisk kvælstoffjernelse er en central proces indenfor avanceret spildevandsrensning. Denne afhandling beskriver anvendelsen af beluftede membran biofilm reaktorer (eng: MABRs) til fuld autotrof kvælstoffjernelse. Denne ret nye kvælstofomsætningsvej baseres på delvis omdannelse af ammonium til....... Som illustreret ved modelundersøgelserne, kan biofilm afrivning påvirke rektorfunktionen alvorligt. Den udførte forsøg for at vurdere om kemisk modificering af biofilmoverfladen kan øge dens modstandsdygtighed overfor afrivning og give forbedret biofilm tykkelseskontrol. Alt i alt kan MABR, hvor ilt...

  4. Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing

    Directory of Open Access Journals (Sweden)

    Jailton Lobo da Costa Lima

    2018-03-01

    Full Text Available Introduction: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. Objectives: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates. Methods: Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR. Results: The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain. Alignment analysis showed an insertion of three nucleotides (T, C and G causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53. Conclusion: The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm. Keywords: Pseudomonas aeruginosa, Biofilm, Multiresistance, Quorum sensing (QS

  5. Professor og DMI

    DEFF Research Database (Denmark)

    Kaas, Eigil

    2010-01-01

    Det er koldt, og det har det været længe. Sammen med sneen har det en selvforstærkende effekt på vintervejret, forklarer professor og meteorolog. Kulde: - Det er koldt, fordi vinden kommer fra et sted, hvor det er koldt. Det er den enkle forklaring på, at Danmark og store dele af Europa lige nu...... oplever meget lave temperaturer - og for Danmarks vedkommende en usædvanlig lang periode med vintervejr. Forklaringen kommer fra professor Eigil Kaas fra Niels Bohr Instituttet ved Københavns Universitet. Han forklarer til jp.dk, at vintervejret dog er betinget af den mere eller mindre tilfældige måde...

  6. Etik og normativitet

    DEFF Research Database (Denmark)

    2012-01-01

    betydningsfuldt, når det udforskede felt kun vanskeligt overlever (Jahoda 1972 (1933)). I 1970’erne adresserer Skjervheim problemstillingen, som forholdet mellem at være deltager eller tilskuer. Hvor forskeren ifølge Skjervheim ikke har andet valg, end at være deltager i det udforskede felt og må tage sit eget...... Nielsen 2005, Egmose 2011, Husted og Tofteng 2006, 2007). Et andet er PAR traditionen, der går mere direkte ind i arbejdet med at definere en etik i aktionsforskningen (s relationer) (Fals Borda og Rahman 1992, Brydon-Miller 2008).......Aktionsforskningens tidligste videnskabsteorietiske overvejelser springer i meget høj grad fra forestillingen om forskerens/forskningens rolle. Hvad er det forskningen kan og skal i et felt? På mange måder er de første erkendelser af dette samstemmende med den samfundsvidenskabelige...

  7. Plan og virkelighed

    DEFF Research Database (Denmark)

    Kaufmann, E.

    Der er dén bagside ved altid at se fremad og lægge planer, at man ikke rigtigt får tid til at se bagud og lære af sine fejl. I denne bog er det imidlertid forsøgt at se tilbage på to mindre planer, som blev lagt for 20 år siden. Hvordan svarer virkelighed til plan?......Der er dén bagside ved altid at se fremad og lægge planer, at man ikke rigtigt får tid til at se bagud og lære af sine fejl. I denne bog er det imidlertid forsøgt at se tilbage på to mindre planer, som blev lagt for 20 år siden. Hvordan svarer virkelighed til plan?...

  8. Bindingssystemer og deres anvendelse

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne

    2016-01-01

    I denne artikel gennemgås litteraturen med særligt fokus på ydeevnen af de bindingssystemer, som anvendes i dag. I PubMed-databasen søgtes efter emneordene ”dental adhesive” og publikationer fra de sidste fem år blev prioriteret. Så vidt muligt fokuseredes på meta-analyser af de begrænsede kliniske...... og diskuteres. Etch & rinse og selvætsende bindingssystemer har været længst på markedet, og for nogle af disse systemer viser kliniske data god retentionsevne. Da de universelle bindingssystemer er relativt nye, er kliniske studier med længere opfølgningstid begrænsede. De få eksisterende studier...

  9. Sindsvidde og inklusion

    DEFF Research Database (Denmark)

    Korsgaard, Morten Timmermann

    2016-01-01

    I denne artikel kastes et utraditionelt blik på den teoretiske og politiske inklusionsdagsorden. Med udgangspunkt i Hannah Arendt's tænkning forsøges det at ’fremmedgøre’ inklusionsbegrebet, for at kunne etablere et nyt vokabular for, hvad det er vi bør tale om i forhold til at udvikle skolen og...... børnenes evne til at indlemme det som er anderledes og det som er fremmed i skolens fællesskab. Derpå følger et forsøg på at re-pædagogisere det at tale om forskellighed og fællesskab i skolen. Igen med udgangspunkt i centrale begreber hos Arendt fremskrives et perspektiv på fællesskab der kunne danne...

  10. Bogen og folket

    DEFF Research Database (Denmark)

    Ladegaard, Jakob

    lyset af Den Franske Revolutions demokratidebat, vil man se, at de ofte også har en politisk dimension. Romantikkens dyrkelse af geniet medfører en udforskning af forholdet mellem de dannede eliter og det jævne folk, dens besættelse af kærlighed rummer idealer om fællesskabets samliv, og dens ideer om......Romantikken bliver ofte fremstillet som en apolitisk eller konservativ strømning i europæisk litteratur, hvor forfattere vendte samfundet ryggen for at fortabe sig i naturen og dyrke det åndelige liv. Men det er på tide at begrave de gamle domme over romantisk litteratur: Læser man epokens værker i...

  11. Salt og forbrugervalg

    DEFF Research Database (Denmark)

    Mørk, Trine; Grunert, Klaus G

    af saltreducerede fødevarer og deres købsintention af disse. Dette blev undersøgt ved at måle forbrugerens viden om salt, anvendelse af salt, ønske om reduktion af salt og købsintention af saltreducerede fødevarer i en web-baseret undersøgelse. Efter den web-baserede undersøgelse, blev de samme mål...... undersøgt, men i et supermarked, hvor deltagerne blev inddelt i fire grupper for at undersøge effekten af priming og saltmærkning. Desuden blev der foretaget 15 kvalitative interviews, for at studere hvem og hvad der karakteriserer de deltagere i eksperimentet, som enten ender med ingen salt......-reducerede produkter at købe eller som ender med at købe alle de salt-reducerede produkter....

  12. Til fiktiv samtale om dannelse og kompetencer

    DEFF Research Database (Denmark)

    Brok, Lene Storgaard

    2016-01-01

    Grundtvig, Brandes og andre betydningsfulde personer deltager i fiktiv samtale om dannelse og kompetencer......Grundtvig, Brandes og andre betydningsfulde personer deltager i fiktiv samtale om dannelse og kompetencer...

  13. Prinsessepiger og popkultur

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    2009-01-01

    I børnehaven Mejsen har en flok piger leget med billeder. Med afsæt i en collage af fotokopierede Bratz-prinsesser har pigerne lavet en fortælling, som er blevet fotograferet, printet ud og hængt op. En anden dag er pigerne selv blevet fotograferet, på en tur en vinterdag. Også disse billeder er...

  14. Stigma og psykiske lidelser

    DEFF Research Database (Denmark)

    Nøhr Christensen, Rikke; Bengtsson, Steen

    Mange mennesker er i forskelligt omfang berørt af psykisk lidelse, men alligevel er psykisk lidelse ikke noget, vi er gode til at tale om og få sat på dagsordenen i den offentlige debat. Det skyldes bl.a., at psykisk lidelse er behæftet med en række fordomme, tabuer og ikke mindst uvidenhed. Vi v...

  15. Plast og Brand

    DEFF Research Database (Denmark)

    Jensen, Jens Kristian Jehrbo

    Dette skrift behandler emnet: plast og brand set i relation til anvendelserne i byggeriet. Den udstrakte brug af plastmaterialer gør det nødvendigt at være opmærksom på forhold vedrørende termisk nedbrydning af brand. En analyse af plastmaterialer kan foretages ved hjælp af ret simple prøver , og...

  16. Oplevelser. Koblinger og transformationer

    DEFF Research Database (Denmark)

    Jantzen, Christian; Jensen, Jens Frederik

    Oplevelser er mellemledet mellem sansning of erfaring. Når vi oplever noget, knyttes der indsigt, mening og formål på vores indtryk. Oplevelser får os til at erkende vores omverden og os selv på nye spændende måder. Oplevelsesøkonomi drejer sig i den sammenhæng om nye kreative tilgange til produk...

  17. Frafald og engagement

    DEFF Research Database (Denmark)

    Jørgensen, Christian Helms; Pedersen, Lene Tanggaard; Nielsen, Klaus

    Denne rapport beskriver de første resultater fra den kvalitative del af et forskningsprojekt om frafald og fastholdelse i dansk erhvervsuddannelse finansieret af Det Strategiske Forskningsråd i perioden 2009-2012. Resultaterne bygger på de første elevinterview gennemført i efteråret 2009 og fokus...... fokuserer eksplicit på elevernes oplevelse af eget engagement eller mangel på samme på erhvervsskolernes grundforløb....

  18. Sanskrit og Latin

    DEFF Research Database (Denmark)

    Bang, Peter Fibiger

    2008-01-01

    Denne kronik præsenterer ligheder påpeget af ny forskning mellem den måde latin og sanskrit fungerede på som kosmopolitiske elitesprog. Udgivelsesdato: 1-7. Aug.......Denne kronik præsenterer ligheder påpeget af ny forskning mellem den måde latin og sanskrit fungerede på som kosmopolitiske elitesprog. Udgivelsesdato: 1-7. Aug....

  19. Film og historie

    DEFF Research Database (Denmark)

    2016-01-01

    Valg af materiale/medie/form: Video med person og skærm til MOOC for elever Valg af arbejdsform: Mundtlig og visuel præsentation af analysemodel trin for trin - som opsamling på enkeltelementer præsenteret i resten af MOOC'et Begrundelse for valg af materiale/medie/form/arbejdsform: Forsøg på at ...

  20. Produktstrukturer og produktmodellering

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik

    1998-01-01

    Paperet beskriver erfaringer opbygning af en struktureringsteori set i relation til anvendelse i produktmodellering. Det væsentligste bidrag er definition af en product familiy master plan, der udgør kernen i en produktmodel. En produktfamily master plan defnieres i paperet som et system besående...... af fire komponenter: en generisk produktstruktur, views, klassebibliotek og bindinger. Product family master planen er implemeteret i en industrivirksomhed og væsentlige rationaliseringer af konstruktionsarbejdet er opnået....

  1. Hoftebrot og kognitiv svikt

    OpenAIRE

    Rørvik, Kim Andre

    2016-01-01

    Bakgrunn for val av tema Etter å ha jobba ekstravakter som sjukepleiarstudent på ortopedisk avdeling har eg erfart at veldig mange eldre blir innlagt på sengeposten etter at dei har pådratt seg eit hoftebrot. Eg har observert at det til tider kan bli veldig komplisert sidan ein del pasientar har redusert kognitiv funksjon og ikkje klarer å ta til seg informasjon eller instruksjonar som blir gitt. Problemstilling Korleis mobilisere pasientar med hoftebrot og kognitiv svikt? Framgan...

  2. Historieformidling, Industrimuseet og intrface

    DEFF Research Database (Denmark)

    Thorhauge, Sally; Olsen, David Holt

    2012-01-01

    Hvad får de unge ud af at komme på museet og gennemføre et undervisningsforløb, hvor de kastes ud i at skulle samarbejde i grupper om at løse opgaver i uvante rammer, og hvor de oven i købet har andre professionelle end deres lærere at spørge til råds? Hvordan er museet som læringsmiljø anderledes...

  3. Lys og Energi

    DEFF Research Database (Denmark)

    Christoffersen, Jens; Hansen, Ellen Kathrine; Hilberth, Thomas

    2004-01-01

    En vigtig målsætning i projektet ”Transparente solceller – fremtidens energiproducerende solafskærmning” er at beskrive hvordan PEC cellen kan og bør indgå i byggeriet. For at skabe et bredt og solid fundament i dette arbejdet, har projektet i to omgange gået i aktiv dialog med de studerende ved ...

  4. Profession, holdning og habitus

    DEFF Research Database (Denmark)

    Ejrnæs, Morten; Monrad, Merete

    2013-01-01

    Uoverensstemmelser mellem pædagoger og småbørnsforældre i daginstitutioner kan være afgørende for forældresamarbejdet, forældrenes tilfredshed og pædagogernes arbejdsliv. Sådanne uoverensstemmelser eller deciderede konflikter kan opstå af forskellige årsager. Særligt kan forskelle i gruppernes vi...

  5. Wound biofilms: lessons learned from oral biofilms

    OpenAIRE

    Mancl, Kimberly A.; Kirsner, Robert S.; Ajdic, Dragana

    2013-01-01

    Biofilms play an important role in the development and pathogenesis of many chronic infections. Oral biofilms, more commonly known as dental plaque,are a primary cause of oral diseases including caries, gingivitis and periodontitis. Oral biofilms are commonly studied as model biofilm systems as they are easily accessible, thus biofilm research in oral diseases is advanced with details of biofilm formation and bacterial interactions being well-elucidated. In contrast, wound research has relati...

  6. New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry.

    Science.gov (United States)

    Coughlan, Laura M; Cotter, Paul D; Hill, Colin; Alvarez-Ordóñez, Avelino

    2016-01-01

    Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated

  7. New weapons to fight old enemies: novel strategies for the (biocontrol of bacterial biofilms in the food industry

    Directory of Open Access Journals (Sweden)

    Laura Maria Coughlan

    2016-10-01

    Full Text Available Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances (EPS, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc., although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses

  8. Uddannelse og social innovation

    DEFF Research Database (Denmark)

    Rasmussen, Palle

    2012-01-01

    Social innovation handler om at udvikle af innovative svar på samfundsmæssige behov, som ikke i tilstrækkeligt omfang dækkes af eksisterende former for privat eller offentlig service. Der er oftest tale om svar, som udvikles af ikke-kommercielle organisationer og aktører gennem kreative processer...... med et væsentligt element af initiativ ”nedefra”. Uddannelse er et af de områder, hvor social innovation både historisk og aktuelt har haft betydning. Historisk er der gennem sociale innovationsprocesser blevet udkrystalliseret former for uddannelse, som har imødekommet væsentlige behov for oplysning...... og kompetence, og som på nogle områder har opnået lang levetid. Fremkomsten og udbredelsen af folkehøjskoler er et centralt eksempel. Ligesom anden innovation sker social innovation inden for rammerne et kompleks af strukturer og institutioner, som kan kaldes et national innovationssystem. Artiklen...

  9. Strategisk compliance og regulering

    DEFF Research Database (Denmark)

    Kühn Pedersen, Mogens

    2016-01-01

    Denne artikel introducerer strategisk compliance og påpeger dens samspil med klassiske og nyere former for reguleringer i digital værdiskabelse. Konteksten er den digitale økonomi, som vokser frem imellem den materielle økonomis bærepiller: Virksomheder og markeder, men består af en helt ny...... materialitet, som er det digitale univers og dets modsvarighed i nye krav til compliance. Den nye materialitet stiller nye krav, hvad angår digitale processer og transaktioner. Klassisk regulering, som aktører ikke selv kan ændre, støder på egenregulering, hvor aktørerne selv opsætter regler for at skabe...... digital værdi. Dette kalder på strategisk compliance. Med digitalisering er strategisk compliance sat på dagsordnen i reguleringsdebatten. Vi hævder, at regulering og egenregulering kan komme til at virke komplementært i det post-industrielle, digitaliserede samfund....

  10. Mobning og social eksklusionsangst

    DEFF Research Database (Denmark)

    Søndergaard, Dorte Marie

    2009-01-01

    afgørende hvilke tænketeknologier, de gør brug af i deres aflæsning af det, der foregår. Der er, som Dorte Marie Søndergaard skriver i sin artikel, Mobning og social eksklusionsangst, afgørende forskel på, om man i forbindelse med børns gensidige foragtproduktion, bruger en skyldsfokuserende tænketeknologi......, der får både børn og voksne til at søge efter en skyldig aggressor og et afmægtigt offer; eller om man bruger en tænketeknologi med fokus på sociale processer, og dermed retter blikket mod de dynamikker mellem børnene, der gør det oplagt for nogle børn at deltage aktivt i cirkulationen af foragt og...... sociale dynamikker, der for tiden findes i denne klasse, at gribe til netop den form for gensidig aflæsning? Hvad er det, de ønsker, frygter, tror etc., som får dem til at gribe til foragtproduktion i stedet for at gøre så meget andet, der også ville kunne tænkes oplagt, når man går i klasse med hinanden...

  11. Sport og etik

    DEFF Research Database (Denmark)

    Møller, Rasmus Bysted

    Sportsidealismens grundsyn på forholdet mellem sport og moral har længe domineret sportsetikken. Opfattelsen, der går ud på, at sporten udgør frugtbar jord for dyrkelse af et moralsk sindelag, fordi sporten indeholder en moralsk dimension i kraft af sin egen-natur, understøttes ikke af den...... forholdet mellem sport og moral kom således til at bekræfte og delvist forklare empirien på området. Endeligt kunne sportsidealismens hovedtese tilbagevises, for så vidt at den omhandler forholdet mellem sport og moral i dette sidste ords moderne betydning. Dette skete i artiklens afsluttende fjerde afsnit......, hvor forskellen mellem antik og moderne etik blev tydeliggjort. På baggrund af den præsenterede undersøgelse af forholdet mellem sport og moral kan vi konkludere, at sporten isoleret set ikke egner sig som arnested for udviklingen af et moralsk sindelag, idet sporten ikke indeholder den af...

  12. Mental sundhed, klasse og livshistorie

    DEFF Research Database (Denmark)

    Dybbroe, Betina

    2016-01-01

    Kapitlet stiller spørgsmål til, hvordan klasserelationer påvirker identitet og handlerummet for børn og deres familier, og skaber betydninger for ulige sundhed. De empiriske eksempler som bidrager til analysen er hentet fra psykiatrisk praksis, hvori børn og familier indgår i relationer til behan...... behandlere og sundhedssystem, og hvori sygdomskategoriseringer skabes. Her får vi et indblik i, hvordan ulige mental sundhed indgår i komplekse sociale livsmønstre af social ulighed, reproduceret over flere generationer....

  13. Umberto Eco og fortolkningens semiotik

    DEFF Research Database (Denmark)

    Frandsen, Finn

    1997-01-01

    En analyse af spørgsmålet om fortolkningens muligheder og grænser, sådan som det bliver formuleret og besvaret i den italienske semiotiker Umberto Ecos teoretiske forfatterskab. Problemstillingen - og dens transformationer hvad angår såvel metasprog, omfang, niveau og fokus - følges fra begyndelsen...... af 60'erne, hvor Eco er inspireret af fænomenologi og hermeneutik (f.eks. i Opera aperta), til begyndelsen af 90'erne, hvor han arbejder med tekstpragmatik og receptionssemiotik. (f.eks. i I limiti dell'interpretazione)...

  14. Team og test

    DEFF Research Database (Denmark)

    Fryd, Krogh, Pernille

    Afhandlingen TEAM & TEST er en systemteoretisk og komparativ interviewundersøgelse af implementeringen af accountability-reformpolitik i grundskolen i Danmark og USA. Formålet med afhandlingen er at frembringe forskningsbaseret viden om accountability-reformpolitikkens mulige indvirkning på...... skolelederes og læreres selvforståelse og pædagogiske praksis i den offentlige grundskole i Danmark og USA. Undersøgelsen identificerer en række forskningsresultater, der indikerer, at selvstyrende teamorganisering, som ramme omkring samarbejdet om implementering af nationale standarder og test, ikke altid har...

  15. Rekruttering og fastholdelse af seniorer

    DEFF Research Database (Denmark)

    Luccat, Dorte

    Denne undersøgelse har til formål at afdække holdninger, praksis, barrierer og muligheder i forhold til rekruttering og fastholdelse af seniorer. Undersøgelsen er baseret på 19 kvalitative interviews med henholdsvis tillidsrepræsentanter og personaleledere på 13 forskellige arbejdspladser. De...... udvalgte arbejdspladser repræsenterer såvel den offentlige som den private sektor samt større (mindst 50 ansatte) og mindre (under 50 ansatte) arbejdspladser. Vi har endvidere besøgt virksomheder, der henholdsvis har og ikke har seniorer ansat, for at indsamle information om holdninger og praksis fra flere...

  16. Lokalisering av arbeidsplasser og boliger

    DEFF Research Database (Denmark)

    Næss, Petter

    2011-01-01

    En miljømessig effektiv lokalisering av arbeidsplasser og boliger sikter mot å begrense - og helst redusere - biltrafikk og miljøproblemer knyttet til bytransport, sammenliknet med alternative lokaliseringer. En effektiv transportmessig lokalisering kan også bidra til å redusere tap av verdifulle...... arealer (f eks jordbruksareal eller natur- og friluftsområder) utenfor dagens tettstedsgrense. Tiltaket må samtidig utformes slik at en kan bevare viktige bomiljøkvaliteter og så mye som mulig av de grønne arealene innenfor tettbebyggelsen....

  17. QStatin, a Selective Inhibitor of Quorum Sensing in Vibrio Species.

    Science.gov (United States)

    Kim, Byoung Sik; Jang, Song Yee; Bang, Ye-Ji; Hwang, Jungwon; Koo, Youngwon; Jang, Kyung Ku; Lim, Dongyeol; Kim, Myung Hee; Choi, Sang Ho

    2018-01-30

    Pathogenic Vibrio species cause diseases in diverse marine animals reared in aquaculture. Since their pathogenesis, persistence, and survival in marine environments are regulated by quorum sensing (QS), QS interference has attracted attention as a means to control these bacteria in aquatic settings. A few QS inhibitors of Vibrio species have been reported, but detailed molecular mechanisms are lacking. Here, we identified a novel, potent, and selective Vibrio QS inhibitor, named QStatin [1-(5-bromothiophene-2-sulfonyl)-1H-pyrazole], which affects Vibrio harveyi LuxR homologues, the well-conserved master transcriptional regulators for QS in Vibrio species. Crystallographic and biochemical analyses showed that QStatin binds tightly to a putative ligand-binding pocket in SmcR, the LuxR homologue in V. vulnificus , and changes the flexibility of the protein, thereby altering its transcription regulatory activity. Transcriptome analysis revealed that QStatin results in SmcR dysfunction, affecting the expression of SmcR regulon required for virulence, motility/chemotaxis, and biofilm dynamics. Notably, QStatin attenuated representative QS-regulated phenotypes in various Vibrio species, including virulence against the brine shrimp ( Artemia franciscana ). Together, these results provide molecular insights into the mechanism of action of an effective, sustainable QS inhibitor that is less susceptible to resistance than other antimicrobial agents and useful in controlling the virulence of Vibrio species in aquacultures. IMPORTANCE Yields of aquaculture, such as penaeid shrimp hatcheries, are greatly affected by vibriosis, a disease caused by pathogenic Vibrio infections. Since bacterial cell-to-cell communication, known as quorum sensing (QS), regulates pathogenesis of Vibrio species in marine environments, QS inhibitors have attracted attention as alternatives to conventional antibiotics in aquatic settings. Here, we used target-based high-throughput screening to identify

  18. Bacillus subtilis biofilm extends Caenorhabditis elegans longevity through downregulation of the insulin-like signalling pathway

    Science.gov (United States)

    Donato, Verónica; Ayala, Facundo Rodríguez; Cogliati, Sebastián; Bauman, Carlos; Costa, Juan Gabriel; Leñini, Cecilia; Grau, Roberto

    2017-01-01

    Beneficial bacteria have been shown to affect host longevity, but the molecular mechanisms mediating such effects remain largely unclear. Here we show that formation of Bacillus subtilis biofilms increases Caenorhabditis elegans lifespan. Biofilm-proficient B. subtilis colonizes the C. elegans gut and extends worm lifespan more than biofilm-deficient isogenic strains. Two molecules produced by B. subtilis — the quorum-sensing pentapeptide CSF and nitric oxide (NO) — are sufficient to extend C. elegans longevity. When B. subtilis is cultured under biofilm-supporting conditions, the synthesis of NO and CSF is increased in comparison with their production under planktonic growth conditions. We further show that the prolongevity effect of B. subtilis biofilms depends on the DAF-2/DAF-16/HSF-1 signalling axis and the downregulation of the insulin-like signalling (ILS) pathway. PMID:28134244

  19. Analysis of the biofilm proteome of Xylella fastidiosa

    Directory of Open Access Journals (Sweden)

    Labate Carlos A

    2011-09-01

    related to quorum sensing, proving the existence of communication between cells, and thus the development of structuring the biofilm (mature biofilm leading to obstruction of vessels and development of disease. This paper reports a first proteomic analysis of mature biofilm of X. fastidiosa, opening new perspectives for understanding the biochemistry of mature biofilm growth in a plant pathogen.

  20. Just-in-Time og Lean Manufacturing

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Filosofi, principper og teknikker i JIT. Princip i Kanban-styring og dimensionering af et Kanban-system. Lean Thinking og Value Stream Mapping.......Filosofi, principper og teknikker i JIT. Princip i Kanban-styring og dimensionering af et Kanban-system. Lean Thinking og Value Stream Mapping....

  1. Børns leg og eksperimenterende virksomhed

    DEFF Research Database (Denmark)

    Damgaard Warrer, Sarah; Broström, Stig

    Børns leg og eksperimenterende virksomhed er et rigt felt med mange perspektiver, indgangsvinkler og nuancer. I denne bog kædes leg og det eksperimenterende og skabende sammen som to gensidigt forbundne fænomener og belyses i pædagogisk og didaktisk perspektiv. Desuden beskrives potentialet i båd...

  2. Webdesign, benspænd og ikoner

    DEFF Research Database (Denmark)

    Engholm, Ida

    2014-01-01

    Web (www) i 1993 blev nettet også forsynet med billeder, lyd, grafik og animationer, og det blev nemmere for ikke-teknisk kyndige brugere at benytte det. Dermed blev det for alvor også relevant at interessere sig for, hvordan man gav grafisk og interaktiv form til websites, søgemaskiner og andre...

  3. Quorum Sensing Disruption in Vibrio harveyi Bacteria by Clay Materials.

    Science.gov (United States)

    Naik, Sajo P; Scholin, Jonathon; Ching, San; Chi, Fang; Herpfer, Marc

    2018-01-10

    This work describes the use of clay minerals as catalysts for the degradation of quorum sensing molecule N-(3-oxooctanoyl)-dl-homoserine lactone. Certain clay minerals as a result of their surface properties and porosity can catalytically degrade the quorum sensing molecule into smaller fragments. The disruption of quorum sensing by clay in a growing Gram-negative Vibrio harveyi bacteria culture was also studied by monitoring luminescence and population density of the bacteria, wherein quenching of bacterial quorum sensing activity was observed by means of luminescence reduction. The results of this study show that food-grade clays can be used as biocatalysts in disrupting bacterial activity in various media.

  4. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    DEFF Research Database (Denmark)

    Hentzer, Morten; Wu, H.; Andersen, Jens Bo

    2003-01-01

    Traditional treatment of infectious diseases is based on compounds that kill or inhibit growth of bacteria. A major concern with this approach is the frequent development of resistance to antibiotics. The discovery of communication systems (quorum sensing systems) regulating bacterial virulence has...... of natural furanone compounds can act as a potent antagonist of bacterial quorum sensing. We employed GeneChip((R)) microarray technology to identify furanone target genes and to map the quorum sensing regulon. The transcriptome analysis showed that the furanone drug specifically targeted quorum sensing...

  5. Characterization of Acinetobacter baumannii biofilm associated components

    Science.gov (United States)

    Brossard, Kari A.

    Acinetobacter baumannii is a Gram-negative aerobic coccobaccillus that is a major cause of nosocomial infections worldwide. Infected individuals may develop pneumonia, urinary tract, wound, and other infections that are associated with the use of indwelling medical devices such as catheters and mechanical ventilation. Treatment is difficult because many A. baumannii isolates have developed multi-drug resistance and the bacterium can persist on abiotic surfaces. Persistence and resistance may be due to formation of biofilms, which leads to long-term colonization, evasion of the host immune system and resistance to treatment with antibiotics and disinfectants. While biofilms are complex multifaceted structures, two bacterial components that have been shown to be important in formation and stability are exopolysaccharides (EPS) and the biofilm-associated protein (Bap). An EPS, poly-beta-1,6-N-acetylglucosamine, PNAG, has been described for E. coli and S. epidermidis. PNAG acts as an intercellular adhesin. Production of this adhesin is dependent on the pga/icaABCD locus. We have identified a homologous locus in A. baumannii 307-0294 that is involved in production of an exopolysaccharide, recognized by an anti-PNAG antibody. We hypothesized that the A. baumannii pgaABCD locus plays a role in biofilm formation, and protection against host innate defenses and disinfectants suggesting that PNAG is a possible virulence factor for the organism. The first aim of this thesis will define the pgaABCD locus. We have previously identified Bap, a protein with similarity to those described for S. aureus and we have demonstrated that this protein is involved in maintaining the stability of biofilms on glass. We hypothesized that A. baumannii Bap plays a role in persistence and pathogenesis and is regulated by quorum sensing. In our second aim we will examine the role of Bap in attachment and biofilm formation on medically relevant surfaces and also determine if Bap is involved in

  6. Godkendelses- og kontrolordninger for byggevarer

    DEFF Research Database (Denmark)

    Høffding Knuttson, H.

    Anvisningen giver en samlet oversigt over alle de godkendelses- og kontrolordninger, der er etableret i henhold til bygningsreglementerne, Dansk Ingeniørforenings normer og danske standarder, samt de benyttede mærkninger af byggevarer....

  7. Direct evaluation of Pseudomonas aeruginosa biofilm mediators in a chronic infection model.

    Science.gov (United States)

    Byrd, Matthew S; Pang, Bing; Hong, Wenzhou; Waligora, Elizabeth A; Juneau, Richard A; Armbruster, Chelsie E; Weimer, Kristen E D; Murrah, Kyle; Mann, Ethan E; Lu, Haiping; Sprinkle, April; Parsek, Matthew R; Kock, Nancy D; Wozniak, Daniel J; Swords, W Edward

    2011-08-01

    Biofilms contribute to Pseudomonas aeruginosa persistence in a variety of diseases, including cystic fibrosis, burn wounds, and chronic suppurative otitis media. However, few studies have directly addressed P. aeruginosa biofilms in vivo. We used a chinchilla model of otitis media, which has previously been used to study persistent Streptococcus pneumoniae and Haemophilus influenzae infections, to show that structures formed in vivo are biofilms of bacterial and host origin within a matrix that includes Psl, a P. aeruginosa biofilm polysaccharide. We evaluated three biofilm and/or virulence mediators of P. aeruginosa known to affect biofilm formation in vitro and pathogenesis in vivo--bis-(3',5')-cyclic dimeric GMP (c-di-GMP), flagella, and quorum sensing--in a chinchilla model. We show that c-di-GMP overproduction has a positive impact on bacterial persistence, while quorum sensing increases virulence. We found no difference in persistence attributed to flagella. We conclude from these studies that a chinchilla otitis media model provides a means to evaluate pathogenic mediators of P. aeruginosa and that in vitro phenotypes should be examined in multiple infection systems to fully understand their role in disease.

  8. strong>Dannelse og dissonanserstrong>

    DEFF Research Database (Denmark)

    Frederiksen, Mons Bissenbakker

    italesætter kønslige identiteter som fænomener, der be­ting­er elevers og læreres faglige præferencer og evner. Det vises også, at materialets itale­sættelse af etnicitet kendetegnes af, at faget anerkender og værdsætter det etnisk dif­ferentierede skolerum, men at det samtidig italesætter minoritetsetniske...

  9. Læring og it

    DEFF Research Database (Denmark)

      Antologien er et bidrag til didaktiske diskussioner om brug af f.eks. programpakker til sprogundervisning, præsentationsprogrammel og konferencesystemer på de videregående uddannelser. Antologien diskuterer ideen om, at multimediale medier og internettet kan understøtte læring, undervisning og ...... samarbejde ud fra konkrete eksempler på it-anvendelser, hvor fokus er på potentialer, barrierer og faldgruber....

  10. Indvandrerkvinders helbred, tradition og tro

    DEFF Research Database (Denmark)

    Dyhr, Lise

    2000-01-01

    Interview sammen med Læge Sajida Fazal og jordemoder Hanne Gylche om erfaringer og løsningsforslag til at forbedre mødet med indvandrerkvinder i Danmark. Udgivelsesdato: 2000/11/6......Interview sammen med Læge Sajida Fazal og jordemoder Hanne Gylche om erfaringer og løsningsforslag til at forbedre mødet med indvandrerkvinder i Danmark. Udgivelsesdato: 2000/11/6...

  11. Tårnet og territoriet

    DEFF Research Database (Denmark)

    Munk, Kasper Green

    2016-01-01

    Tyskland står midt i en kulturkamp, der handler om flygtninge og indvandrere, og hvor arven fra nazismen og kommunismen spiller en meget stor rolle. En rejse til Dresden med litteraturen ved hånden kan gøre os klogere på baggrunden for, hvad der foregår. Det handler om sammenstød mellem drøm og v...

  12. Unge, Holdspil og Medborgerskab

    DEFF Research Database (Denmark)

    Ryom, Knud Eske

    coaching/mentoring. Behovet for dette skal ses i lyset af en senmoderne kontekst, hvor udvikling blandt unge i vid udstrækning handler om at ”skabe sig selv” og synes karakteriseret ved en udpræget grad af kollektivt orienteret individualisme. Dermed forekommer det plausibelt, at der er en sammenhæng......, coaching/mentoring og læring. Derefter præsenteres de enkelte metodiske værktøjer (multimethod), som har været brugt til at indsamle empiri. Hvordan det kan kobles en kvantitative metode som spørgeskemaer i et aktionsforskningsprojekt diskuteres også, samt hvordan metoderne er brugt strategisk undervejs i...... medborgerskab introduceres. Hvorefter mere generelle emner bearbejdes, såsom: a) Unge fra socialt udsatte boligområder, med fokus på hvordan samfundet oplever denne gruppe. b) Nogle af de særlige kendetegn ved det senmoderne samfund, og hvordan coaching og identitet bliver relevant i et sådant samfund. c...

  13. Hjem og hjemlighed

    DEFF Research Database (Denmark)

    Winther, Ida

    , samtidig med at vi sidder bag den låste dør foran skærmen, eller mens vi cirkulerer i den sociale trafik med mobiltelefonen i hånden. Vi kan på en og samme tid ?stay at home?, ?go places? og være ?NoWhere?. No where og now here er ingen steder, alle steder og lige præcis dette sted på én og samme tid. Det...... demands and invade us. We can be in the global space, even though we simultaneously sit behind a locked door in front of a screen, or while we are in circulation in the social traffic mobile phone in hand. We can be said to ?stay at home?, ?go places? and be ?NoWhere?, almost at the same time. ?Now here...... about a puzzle with a lot of pieces ? heterogeneous and non-contemporaneous, both in form and substance, but we also acknowledge that even more pieces could have been relevant for the investigatation.The material is polymorph, and I let it be so, and my source material is inexhaustible. Cultural...

  14. Eksempler og merbetydning

    DEFF Research Database (Denmark)

    Hansen, Brian Benjamin

    2016-01-01

    Eksempler er gode, når de indeholder merbetydning. Det er i kort form argumentet i dette kapitel, der tager udgangspunkt i psykoanalysen, repræsenteret ved Sigmund Freud og Slavoj Žižek. Kapitlet fokuserer på, hvordan Freud giver eksempler på det ubevidste. Man kan aldrig udtømme det ubevidste, og...... ethvert eksempel på det ubevidste vil på en måde være for lidt. Som kapitlet fremlægger det, er der alligevel både hos Freud og Žižek det bemærkelsesværdige, at de har en meget aktiv brug af eksempler, hvor eksemplerne hele tiden presses til det yderste. Det ubevidste findes i en vis forstand kun, idet vi...... giver eksempler på det, og det argumenteres således, at der, når man analyserer med Freud og Žižek, er mere i eksemplet end i det begreb, det egentlig blot skulle eksemplificere. Det redegøres for, at resultatet af denne tilgang er en meget dynamisk undersøgelsesproces, hvor der søges efter overraskende...

  15. Motivation og handlingskapacitet

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Kristensen, Nicolai; Pedersen, Lene Holm

    2012-01-01

    Der har i flere år være en interesse for at undersøge motivationen hos producenterne af offentlige ydelser, mens der i mindre grad findes empiriske analyser af brugernes handlingskapacitet. Artiklen råder bod på dette ved at analysere forskelle i motivation og handlingskapacitet på fire serviceom......Der har i flere år være en interesse for at undersøge motivationen hos producenterne af offentlige ydelser, mens der i mindre grad findes empiriske analyser af brugernes handlingskapacitet. Artiklen råder bod på dette ved at analysere forskelle i motivation og handlingskapacitet på fire...... serviceområder (skoler, dagpasning, hospitaler og videregående uddannelser). Der anvendes henholdsvis et veletableret mål for public service motivation (n=377 producenter) og et nyudviklet mål for handlingskapacitet (n=1056 brugere). Resultaterne viser, at der er relativt højest handlingskapacitet og public...... service motivation på daginstitutionsområdet efterfulgt af skoleområdet, mens de videregående uddannelser placerer sig relativt lavest på begge variable. Hospitalsbrugerne har næsten lige så lav handlingskapacitet som brugerne af de videregående uddannelser, mens de hospitalsansattes public service...

  16. Synthetic quorum sensing in model microcapsule colonies

    Science.gov (United States)

    Shum, Henry; Balazs, Anna C.

    2017-08-01

    Biological quorum sensing refers to the ability of cells to gauge their population density and collectively initiate a new behavior once a critical density is reached. Designing synthetic materials systems that exhibit quorum sensing-like behavior could enable the fabrication of devices with both self-recognition and self-regulating functionality. Herein, we develop models for a colony of synthetic microcapsules that communicate by producing and releasing signaling molecules. Production of the chemicals is regulated by a biomimetic negative feedback loop, the “repressilator” network. Through theory and simulation, we show that the chemical behavior of such capsules is sensitive to both the density and number of capsules in the colony. For example, decreasing the spacing between a fixed number of capsules can trigger a transition in chemical activity from the steady, repressed state to large-amplitude oscillations in chemical production. Alternatively, for a fixed density, an increase in the number of capsules in the colony can also promote a transition into the oscillatory state. This configuration-dependent behavior of the capsule colony exemplifies quorum-sensing behavior. Using our theoretical model, we predict the transitions from the steady state to oscillatory behavior as a function of the colony size and capsule density.

  17. Ledelse og arbejde under forandring

    DEFF Research Database (Denmark)

    Csonka, Agi Eva

    Inden for såvel dele af arbejdssociologien som blandt managementkonsulenter og virksomhedsledere er det en udbredt opfattelse, at nye organisationsformer er på vej. Virksomheder skal tilpasse sig stadig mere turbulente omgivelser, og der stilles større krav om service og kvalitet. For at sikre op...

  18. Trafikfarlige Skoleveje - Definition og udpegning

    DEFF Research Database (Denmark)

    Madsen, Jens Chr. Overgaard; Schmidl Søbjærg, Stig; Blynning, Edith

    2008-01-01

    Rambøll Nyvig og Herning Kommune har udviklet en model til udpegning af trafikfarlige skoleveje. Modellen sikrer, at vejnettet kan beskrives og prioriteres efter, hvor det er mest farligt og utrygt for skolebørn at færdes. Modellen kan anvendes i identifikationen af befordringsberettigede elever,...

  19. Æstetik og portfolio

    DEFF Research Database (Denmark)

    Hyldahl, Kirsten Kofod; Sams, Pernille; Egelund, Karen Stine

    2017-01-01

    Nærværende artikel præsenterer resultaterne af udviklingsprojektet ”Portfolio og æstetik” på pædagoguddannelsen i Hjørring. Projektet har til formål, gennem æstetisk formsprog, at stilladsere og fastholde de studerendes læreprocesser samt udvikle og implementere portfolio i studieaktiviteter på...

  20. Demokrati og skolens demokratiske dannelse

    DEFF Research Database (Denmark)

    Lindhardt, Eva

    2013-01-01

    I dette kapitel belyses demokrati idehistorisk, og der præsenteres og problematiseres forskellige syn på demokrati. Der laves en komparativ analyse af Alf Ross' forståelse af demokrati som styreform og Hal Kochs forståelse af demokrati som livsform. Herefter undersøges, hvordan definitionen af...

  1. Staten, folkekirken og dansk sekularisme

    DEFF Research Database (Denmark)

    Dabelsteen, Hans Boas

    2012-01-01

    Dette kapitel bringer et forsøg på at begrebsliggøre grænsedragningen mellem religion og politik, med det formål at tydeliggøre de værdier, rationaler og magtformer, der ligger i dansk kirke- og religionspolitik. Hovedargumentet er, at politisk diskussion blandt ledende politikere ikke tager udga...

  2. Sygepleje mellem pakker og personer

    DEFF Research Database (Denmark)

    Sandholm Larsen, Niels

    2010-01-01

    og af problemer med at rekruttere og fastholde sundhedsfaglig arbejdskraft. Som følge af demografiske ændringer antages særligt behandling og rehabilitering af kronisk syge ældre at udgøre et voksende indsatsområde. Sygeplejerskernes faglige organisation har været aktiv i etablering af kommunale...

  3. Om begreberne moral og etik

    DEFF Research Database (Denmark)

    Nielsen, Carsten Fogh

    2016-01-01

    Denne artikel er et bidrag til det begrebsafklarende arbejde med at forstå betydningen af og forskellene på begreberne "etik" og "moral". Artiklen giver en kort, begrebshistorisk oversigt over nogle af de vigtigste skridt i etik- og moralbegrebets udvikling. Der findes formodentlig ikke én korrekt...

  4. Alfred Nobel og hans priser

    DEFF Research Database (Denmark)

    Nielsen, Henry

    2017-01-01

    Siden 1901er der næsten hvert år blevet uddelt nobelpriser for fysik, kemi, fysiologi eller medicin, litteratur og fredsarbejde. Men hvad var det, der fik prisernes ophavsmand til at belønne netop disse fem felter? Og hvordan finder de ansvarlige i Stockholm og Oslo frem til årets prisvindere. De...

  5. Politisk retorik, curriculum og praksis

    DEFF Research Database (Denmark)

    Kristjansdottir, Bergthora

    2017-01-01

    orienteret fag i en globaliseret verden. Bergthóra Kristjánsdóttir Lektor, ph.d., DPU Aarhus Universitet. Underviser på DAV og masteruddannelsen i dansk som andetsprog. Forsker i uddannelsespolitik på makro- og mikroniveau, herunder minoriteter/majoriteter, curriculum, tosprogethed, dansk og dansk som...

  6. Demokratiseret forskning og spilbaseret undervisning

    DEFF Research Database (Denmark)

    Hansen, Sidse Damgaard; Magnussen, Rikke; Sherson, Jacob Friis

    2012-01-01

    Vi vil ved hjælp af et online socialt computerspil forsøge at løse en aktuel og meget resourcekrævende teknologisk udfordring – at designe verdens kraftigste kvantecomputer. I the Quantum Computer Game skal spillerne på en sjov og nem måde udforske og udvikle kvantecomputerens fulde potentiale. Vi...

  7. Om guldbiller, Bach og basepar

    DEFF Research Database (Denmark)

    Mogensen, T.E.

    2003-01-01

    I sin stærkt encyklopædiske roman The Gold Bug Variations søger den amerikanske forfatter Richard Powers gennem utallige detaljer, synekdoker og intrikate forbindelser at inddrage al verden og radikalt udvide romanens rum. Men romanen er også, eller især, en fortælling om kærlighed....

  8. Indvandring, integration og etnisk segregation

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    I denne publikation belyses udviklingen i indvandrernes bosætning i Danmark, analyserer årsagerne til at mange indvandrere er blevet bosat i den almene sektor og koncentreret i bestemte byområder og belyser sammenhængen mellem bosætningen og indvandrernes integration i samfundet. Vi tager afsæt i...

  9. Om hugorme, dyrekranier og tordensten

    DEFF Research Database (Denmark)

    Søvsø, Mette Højmark; Søvsø, Morten; Siggaard, Anna Louise

    2016-01-01

    Bygningsofre og andre beslægtede fænomener som udtryk for folketro er velkendte fra både arkæologiske og etnologiske undersøgelser i Danmark. Mens mulighederne for nye etnologiske optegnelser ebber ud, giver et voksende arkæologisk materiale til gengæld mulighed for at kaste nyt lys over emnet og...

  10. Psykiatrisk og klinisk psykologisk assessment

    DEFF Research Database (Denmark)

    Poulsen, Stig Bernt; Simonsen, Erik

    2017-01-01

    i centrum og med en bred videnskabelig tilgang. Alle psykiske lidelser i WHO´s diagnoseliste ICD-10 bliver gennemgået med fokus på årsagsforhold, forekomst, diagnostik og behandling, og der refereres desuden til diagnoserne i den nyeste udgave af den amerikanske diagnoseliste (DSM-5). Fremstillingen...

  11. Unge i kunst- og kulturprojekter

    DEFF Research Database (Denmark)

    Nielsen, Louise Yung; Sørensen, Niels Ulrik

    for ungeaktiviteter i hele landet. Model forsøget, som nu har kørt i tre år, består af 10 projekter, der favner musik, teater, film, litteratur, arkitektur, projektmageri og design. Projekterne foldes ud i ungdomskulturhuse, kulturinstitutioner, folkeskoler og i offentlige rum, hvor unge færdes og lever. I...

  12. Plasmafysik og fusionsenergi - fremtidens energikilde

    DEFF Research Database (Denmark)

    Dam Heiselberg, Bodil; Heiselberg, Henning

    Fusionsreaktoren ITER bygges i disse år i Frankrig af EU, Kina, Japan, Rusland, Indien, Sydkorea og USA og afløser JET i England. ITER er nok sidste trin i forskningsfusionsreaktorer. ITER forventes at kunne producere mere energi, end der bruges til at køre den, og vil dermed være den første...

  13. Inhibition of quorum sensing-mediated virulence in Serratia marcescens by Bacillus subtilis R-18.

    Science.gov (United States)

    Devi, Kannan Rama; Srinivasan, Subramaniyan; Ravi, Arumugam Veera

    2018-04-13

    Serratia marcescens is an opportunistic human pathogen causing various nosocomial infections, most importantly urinary tract infections (UTIs). It exhibits increased resistance towards the conventional antibiotics. This study was aimed to evaluate the anti-virulence effect of a rhizosphere soil bacterium Bacillus subtilis strain R-18 against the uropathogen S. marcescens. First, the bacterial cell-free culture supernatant (CFCS) of B. subtilis strain R-18 was evaluated for its quorum sensing inhibitory (QSI) potential against biomarker strain Chromobacterium violaceum and the test pathogen S. marcescens. The B. subtilis R-18 CFCS effectively inhibited the quorum sensing (QS)-mediated violacein pigment production in C. violaceum and prodigiosin pigment production in S. marcescens. Furthermore, B. subtilis R-18 CFCS was successively extracted with different solvent systems. Of these solvents, B. subtilis R-18 petroleum ether (PE) extract showed inhibition in biofilm formation, protease, lipase, and hemolysin productions in S. marcescens. Fourier transform infrared spectroscopic (FT-IR) analysis revealed the alterations in the cellular components of bacterial cell pellets obtained from B. subtilis R-18 PE extract treated and untreated S. marcescens. The differential gene expression study further validated the downregulation of virulence-associated genes. Characterization of the active principle in B. subtilis R-18 PE extract by gas chromatography-mass spectrometry (GC-MS) analysis showed the presence of multiple compounds with therapeutic values, which could possibly reduce the QS-dependent phenotypes in S. marcescens. Copyright © 2018. Published by Elsevier Ltd.

  14. Forflytning: shear og friktion

    DEFF Research Database (Denmark)

    2005-01-01

    friktion). Formålet med filmprojektet er: At give personalet i Apopleksiafsnittet viden om shear og friktion, så det motiveres til forebyggelse. Mål At udarbejde et enkelt undervisningsmateriale til bed-side-brug Projektbeskrivelse (resume) Patienter med apopleksi er særligt udsatte for tryksår, fordi de...... ofte er immobile, har svært ved at opretholde en god siddestilling eller ligger tungt i sengen som følger efter apopleksien Hvis personalet bruger forkert lejrings-og forflytningsteknik, udsættes patienterne for shear og friktion. Målgruppen i projektet er de personer, der omgås patienterne, dvs...

  15. Livschancer og mobilitet

    DEFF Research Database (Denmark)

    D. Munk, Martin

    sociale positioner end de lidt ældre fødselskohorter? Ved chance tænkes på begrebet livschance, som dels kan anvendes som et empirisk begreb, f.eks. som rækkeprocenter i en kontingenstabel (jf. Hansen 1995), og dels som et mere teoretisk sociologisk begreb i Max Webers tradition, som refererer til en...... persons ”klasse situation”, der indebærer en vis sandsynlighed for at have adgang til varer, forbrug og anerkendelse fra andre personer (Weber 1978: 302; Goldthorpe 1996). Her undersøges positionen som akademiker/direktør og som ikke-faglært arbejder, typiske yderpositioner i det sociale hierarki....

  16. Offentlighed og Public Relations

    Directory of Open Access Journals (Sweden)

    Lars Heltoft

    1993-09-01

    Full Text Available Lars Heltoft, der er en af grundlæggerne af Public Relationsuddannelsen på Roskilde Universitetscenter, kaster i artiklen et kritisk blik på den akademiske forskning i feltet public relations. Selv i nyere udgaver af PR-forskningen - af mange anset for "progressive", f.eks. James Grunings og Jon Whites arbejder - ser Lars Heltoft tydelige spor af PR- professionens selvforståelse og legitimationsbehov. Resultatet er, at den "offentlighed", der burde være kernen i den videnskabelige beskæftigelse med public relations, "forsvinder i den blå luft". Han argumenterer for, at Habermas´ forestilling om "offentlighed" stadig institutionaliserer mulig- heden for kritisk diskurs inden for feltet, samtidig med at han i sproghand- lingsteoretisk perspektiv problematiserer Habermas´ legitimationsbegreb, fordi det undtager private virksomheder og organisationer.

  17. Kenningar og Metaforar

    Directory of Open Access Journals (Sweden)

    Silvia Lutter

    2009-03-01

    Full Text Available Metaforen er eit kjent stilistisk middel i litteraturen. Han er allereie omtalt hjå Aristoteles og brukt i prosa og lyrikk den dag i dag. Kenningen, derimot, vart framom alt brukt av skaldane i den norrøne tida. I dag kjennes det heller tilgjort å bruke kenningar som stilistiske middel. Eg vil setje fram ein hypotese om at kenningar kan vere metaforar, til trass for forskjellen i bruken av dei to. Først skal eg presentere korleis eg kom fram til hypotesen. Så skal eg prøve hypotesen på døme frå eit norrønt skaldedikt og sjå om påstanden verkar sannsynleg. Viss han gjer det, bør han drøftast vidare ved ei seinare anledning.

  18. Facebook og social ambivalens

    DEFF Research Database (Denmark)

    Tække, Jesper

    2013-01-01

    Facebook er et prominent eksempel på de digitale medier, der i disse år ryster samfundet med sine nye (u)muligheder for ageren, interaktion og deling af information. Dette kapitel analyserer, hvordan befolkningen med introduktionen af Facebook som nyt medie aktuelt udsættes for en række sociale...... mediemiljø. Et vigtigt spørgsmål herunder er, om Facebook med sin aktuelle funktionelle arkitektur forstærker eller direkte initierer sociale ambivalenser, set op imod de digitale mediers generelle potentialitet for transparens og selektion, og dermed kommer til at bevirke, at samfundet har unødigt svært ved...

  19. Bacterial Biofilm Control by Perturbation of Bacterial Signaling Processes

    Directory of Open Access Journals (Sweden)

    Tim Holm Jakobsen

    2017-09-01

    Full Text Available The development of effective strategies to combat biofilm infections by means of either mechanical or chemical approaches could dramatically change today’s treatment procedures for the benefit of thousands of patients. Remarkably, considering the increased focus on biofilms in general, there has still not been invented and/or developed any simple, efficient and reliable methods with which to “chemically” eradicate biofilm infections. This underlines the resilience of infective agents present as biofilms and it further emphasizes the insufficiency of today’s approaches used to combat chronic infections. A potential method for biofilm dismantling is chemical interception of regulatory processes that are specifically involved in the biofilm mode of life. In particular, bacterial cell to cell signaling called “Quorum Sensing” together with intracellular signaling by bis-(3′-5′-cyclic-dimeric guanosine monophosphate (cyclic-di-GMP have gained a lot of attention over the last two decades. More recently, regulatory processes governed by two component regulatory systems and small non-coding RNAs have been increasingly investigated. Here, we review novel findings and potentials of using small molecules to target and modulate these regulatory processes in the bacterium Pseudomonas aeruginosa to decrease its pathogenic potential.

  20. Piper betle leaf extract affects the quorum sensing and hence virulence of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Datta, Siraj; Jana, Debanjan; Maity, Tilak Raj; Samanta, Aveek; Banerjee, Rajarshi

    2016-06-01

    Quorum sensing (QS) plays an important role in virulence of Pseudomonas aeruginosa, blocking of QS ability are viewed as viable antimicrobial chemotherapy and which may prove to be a safe anti-virulent drug. Bioactive components from Piper betle have been reported to possess antimicrobial ability. This study envisages on the anti-QS properties of ethanolic extract of P. betle leaf (PbLE) using P. aeruginosa PAO1 as a model organism. A marked reduction in swarming, swimming, and twitching ability of the bacteria is demonstrated in presence of PbLE. The biofilm and pyocyanin production also shows a marked reduction in presence of PbLE, though it does not affect the bacterial growth. Thus, the studies hint on the possible effect of the bioactive components of PbLE on reducing the virulent ability of the bacteria; identification of bioactive compounds should be investigated further.

  1. Kjemisk klima og helseproblemer

    Directory of Open Access Journals (Sweden)

    Jul Låg

    2009-10-01

    Full Text Available  SAMMENDRAGFysiske klimafaktorer har alltid vært fulgt med oppmerksomhet fra menneskene, mens interessen forkjemisk klima er av nyere dato. Viktige årsaker til den nye interessen er at naturforurensning tilleggesstørre betydning enn før, og at det i vår tid er et utbredt ønske om sterkere innsats i forebyggendehelsearbeid. Det er påvist at i humusdekket i naturlig jordsmonn avtar innholdet av hovedbestandelersom natrium og magnesium stort sett med stigende avstand fra havet. Lignende lovmessigheter gjelderogså for sporstoffer som jod, brom, klor og selen. I tillegg avtar disse også med nedbørsmengden. Dettetyder på at tilførsel av marine elementer til jordsmonn via nedbør er en meget viktig geokjemisk prosess,og de kan ha stor betydning for menneskers og dyrs helse. Endringer i nedbørens surhetsgrad ogvariasjoner i mengdeforholdet mellom de stoffer som tilføres jordsmonnet kan gi betydelige utslag iflora og fauna. Store befolkningsgrupper påvirkes til enhver tid av viktige kjemiske klimafaktorer, ogdet er sterkt ønskelig at forskning og veiledning innenfor dette fagfeltet intensiveres.Låg J. Chemical climate and health problems. Nor J Epidemiol 1998; 8 (1: 19-20. ENGLISH SUMMARYPhysical factors of the climate have for a long time been considered to be of great interest. Variations inthe chemical climate have received a growing attention only in the period after World War II, a trendwhich is due to an increasing interest in pollution and preventive health activities in our times. Thecontents of some of the major constituents in surface soil, such as sodium and magnesium, have beenfound to decrease with increasing distance from the sea. The contents of trace elements, such as iodine,bromine, chlorine, and selenium also show this type of distributional patterns, but in addition thecontents in the soil of these elements increase with the amount of precipitation. Such data indicate thatairborne transportation of elements from the

  2. GIS og geodata

    DEFF Research Database (Denmark)

    Balstrøm, Thomas

    2008-01-01

    Interview med Thomas Balstrøm om anvendelser af geografiske informationssystemer (GIS) i relation til forskning i jordbundsgeografiske problemstillinger. Bl.a. om forskning i rumlige analyser og inddragelse af rumlig statistik til at finde sammenhænge i geografiske data.......Interview med Thomas Balstrøm om anvendelser af geografiske informationssystemer (GIS) i relation til forskning i jordbundsgeografiske problemstillinger. Bl.a. om forskning i rumlige analyser og inddragelse af rumlig statistik til at finde sammenhænge i geografiske data....

  3. Teatervaner og teaterstatistik

    DEFF Research Database (Denmark)

    Jarl, Stig

    2015-01-01

    frekvenser for oplevelse af teater og anden scenekunst, hvilket for det s.k. overordnede teaterbegreb (skuespil, opera, ballet/dans, musicals/teaterkoncert, dukketeater) giver et resultat på mellem 7 og 12 mio. (afhængigt af om man vælger det ene eller andet niveau af svarintervallerne). Dette resultat...... teateraktivitet, er det tilfældet for brugere af teater. Artiklen er baseret på et paper, som jeg har fremlagt på 6th Nordic Conference on Cultural Policy Research – nccpr 2013 (København august 2013)....

  4. Moms og fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    1999-01-01

    I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af reguleringsforpligte......I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af...

  5. Til kroppen og hovedet

    DEFF Research Database (Denmark)

    Bonde, Anders

    2012-01-01

    Anmeldelse af koncertarrangementet "A Song for Bayes" på Skråen, Aalborg, d. 27. februar 2012 - et musikalsk eksperiment, der undersøger, om man kan lave musik ud fra Bayesianske net, og hvordan (http://bayesmusic.wordpress.com/hvad-er-en-sang-for-bayes/).......Anmeldelse af koncertarrangementet "A Song for Bayes" på Skråen, Aalborg, d. 27. februar 2012 - et musikalsk eksperiment, der undersøger, om man kan lave musik ud fra Bayesianske net, og hvordan (http://bayesmusic.wordpress.com/hvad-er-en-sang-for-bayes/)....

  6. Produktivisme og asocialitet

    DEFF Research Database (Denmark)

    Nielsen, Birger Steen

    2012-01-01

    Politisk satses der på en øget produktivitet, men der stilles ikke spørgsmålstegn ved hvad der skal produceres. Den blinde produktivitetssatsning (produktivisme) er i sin kerne asocial og blokerer en omstilling til bæredygtighed.......Politisk satses der på en øget produktivitet, men der stilles ikke spørgsmålstegn ved hvad der skal produceres. Den blinde produktivitetssatsning (produktivisme) er i sin kerne asocial og blokerer en omstilling til bæredygtighed....

  7. Mellem Detroit og Danmark

    DEFF Research Database (Denmark)

    Christensen, Lars K.

    2013-01-01

    Danmark var et af de første steder, man producerede Ford i Europa – fra 1919 på Nørrebro – og det blev hurtigt en succes. Sidenhen tvang danske arbejdere verdens største bilproducent til at acceptere »den danske model«. Dog kun for en tid.......Danmark var et af de første steder, man producerede Ford i Europa – fra 1919 på Nørrebro – og det blev hurtigt en succes. Sidenhen tvang danske arbejdere verdens største bilproducent til at acceptere »den danske model«. Dog kun for en tid....

  8. Repurposing metformin as a quorum sensing inhibitor in ...

    African Journals Online (AJOL)

    Background: Quorum sensing is a mechanism of intercellular communication that controls the production of virulence factors in Pseudomonas aeruginosa. Inhibition of quorum sensing can disarm the virulence factors without exerting stress on bacterial growth that leads to emergence of antibiotic resistance. Objectives: ...

  9. Æstetik og udvikling - indledning

    DEFF Research Database (Denmark)

    Austring, Bennyé D.; Sørensen, Merete

    2007-01-01

    I indledningen til antologien Æstetik og udvikling præsenteres 10 udviklingsprojekter og rammen om dem: Kompetencecenter for Æstetik og Læring. Redaktørerne Bennyé D. Austring og Merete Sørensen gør også rede for centrets teoretiske inspirationskilder, især Hansjörg Hohr og Anne Bamford, og de...

  10. Quorum sensing: a non-conventional target for antibiotic discovery.

    Science.gov (United States)

    Naik, Varsha; Mahajan, Girish

    2013-10-01

    Quorum sensing (QS) is known to regulate different functions viz. pathogenesis, biofilm formation, and host colonization, along with other functions by regulating bacterial virulence determinants. Therefore, QS is deemed to be an interesting target to modulate pathogenesis. Also, there have been global reports of continuous emergence of antibiotic-resistant microbes; hence, an alternative treatment that compliments antibiotic activity is highly desirable. One such approach is to look for QS inhibitors, which can quench the virulence phenotypes exerted by pathogenic bacteria and compliment antibiotic treatment. In the present study, Pseudomonas aeruginosa strain was used as the model organism which produces three pigments viz. pyocyanin, pyoverdin and pyorubin. Pyocyanin synthesis is reported to be QS dependent and is one of the virulence factors of P. aeruginosa. Hence, we envisage inhibition of pyocyanin pigment would indicate QS inhibition (QSI). Auto-inducers like N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL/3-oxo-C12-HSL) and N-butyryl-L- homoserine lactone (BHL/C4-HSL) were used to enhance the pyocyanin pigment production by the model strain at different doses and time points. BHL, at 25 microM was found to be a better inducer of pyocyanin. Tannic acid (TA) was tested to suppress this pigment synthesis and it was found to be effective when assessed at different time points. About 5.12 mg/mL TA was found to be the optimum concentration at which pyocyanin was inhibited by 77.3%. Thus, we confirm that TA can be used as a QSI, either in its purest form or in the crude form found in various plant species, and could be considered for development to compliment antibiotic therapy.

  11. Barn og diabetes type 1

    OpenAIRE

    Ramstad, Marte Elise; Sagbakken, Sina Bekkelund

    2017-01-01

    Bacheloroppgave sykepleie, 2017 Bakgrunn: Vi har valgt denne problemstillingen fordi diabetes type 1 er svært utbredt hos barn i Norge. Videre har vi lite erfaringer med barn og ønsket å lære mer om denne pasientgruppen. Vi ønsket videre å se på hvordan vi kan undervise og veilede for å gi god og hensiktsmessig sykepleie til barn og deres familier. Hensikt: Finne ut hvordan sykepleier kan fremme egenomsorg hos barn med diabetes gjennom veiledning og undervisning. Dette er noe som sykepl...

  12. Andelsselskabernes seneste udvikling og resultater

    DEFF Research Database (Denmark)

    Hansen, Henning Otte

    2015-01-01

    Andelsselskaber har spillet - og spiller stadig - en væsentlig rolle ikke bare i landbrugs- og fødevaresektoren, men også i hele den danske samfundsøkonomi. Udviklingen gennem de seneste 10-15 år viser, at andelsselskaberne har formået at vokse og at øge deres andel af den samlede omsætning. Samt...... de danske andelsselskaber falder kun svagt, mens antallet af ansatte er svagt stigende. Det skyldes dog i vid udstrækning selskabernes internationalisering, hvorved antallet af udenlandske medlemmer og ansatte stiger....

  13. Samarbejde mellem profession og uddannelse

    DEFF Research Database (Denmark)

    Nielsen, Birgitte Lund

    2011-01-01

    Review af resultater fra 10 års publikationer i Teaching and Teacher Education i relation til samarbejde mellem profession og uddannelse i partnerskaber og forsøgsskoleregi viser, at der er bred konsensus om, at det centrale formål er alle aktørers læring gennem bedre praktik i den primære...... konkrete samarbejder mellem profession og uddannelse; FoU, der både undersøger de resultater, der opnås gennem sådanne samarbejder, og de fremmende og hæmmende faktorer for udvikling af selve samarbejdet....

  14. Role of Streptococcus mutans surface proteins for biofilm formation

    Directory of Open Access Journals (Sweden)

    Michiyo Matsumoto-Nakano

    2018-02-01

    Full Text Available Summary: Streptococcus mutans has been implicated as a primary causative agent of dental caries in humans. An important virulence property of the bacterium is its ability to form biofilm known as dental plaque on tooth surfaces. In addition, this organism also produces glucosyltransferases, multiple glucan-binding proteins, protein antigen c, and collagen-binding protein, surface proteins that coordinate to produce dental plaque, thus inducing dental caries. Bacteria utilize quorum-sensing systems to modulate environmental stress responses. A major mechanism of response to signals is represented by the so called two-component signal transduction system, which enables bacteria to regulate their gene expression and coordinate activities in response to environmental stress. As for S. mutans, a signal peptide-mediated quorum-sensing system encoded by comCDE has been found to be a regulatory system that responds to cell density and certain environmental stresses by excreting a peptide signal molecule termed CSP (competence-stimulating peptide. One of its principal virulence factors is production of bacteriocins (peptide antibiotics referred to as mutacins. Two-component signal transduction systems are commonly utilized by bacteria to regulate bacteriocin gene expression and are also related to biofilm formation by S. mutans. Keywords: Streptococcus mutans, Surface proteins, Biofilm, Signal transduction

  15. Quorum decision-making in foraging fish shoals.

    Directory of Open Access Journals (Sweden)

    Ashley J W Ward

    Full Text Available Quorum responses provide a means for group-living animals to integrate and filter disparate social information to produce accurate and coherent group decisions. A quorum response may be defined as a steep increase in the probability of group members performing a given behaviour once a threshold minimum number of their group mates already performing that behaviour is exceeded. In a previous study we reported the use of a quorum response in group decision-making of threespine sticklebacks (Gasterosteus aculeatus under a simulated predation threat. Here we examine the use of quorum responses by shoals of sticklebacks in first locating and then leaving a foraging patch. We show that a quorum rule explains movement decisions by threespine sticklebacks toward and then away from a food patch. Following both to and from a food patch occurred when a threshold number of initiators was exceeded, with the threshold being determined by the group size.

  16. Quorum quenching properties of Actinobacteria isolated from Malaysian tropical soils.

    Science.gov (United States)

    Devaraj, Kavimalar; Tan, Geok Yuan Annie; Chan, Kok-Gan

    2017-08-01

    In this study, a total of 147 soil actinobacterial strains were screened for their ability to inhibit response of Chromobacterium violaceum CV026 to short chain N-acyl homoserine lactone (AHL) which is a quorum sensing molecule. Of these, three actinobacterial strains showed positive for violacein inhibition. We further tested these strains for the inhibition of Pseudomonas aeruginosa PAO1 quorum sensing-regulated phenotypes, namely, swarming and pyocyanin production. The three strains were found to inhibit at least one of the quorum sensing-regulated phenotypes of PAO1. Phylogenetic analysis of the 16S rRNA gene sequences indicated that these strains belong to the genera Micromonospora, Rhodococcus and Streptomyces. This is the first report presenting quorum quenching activity by a species of the genus Micromonospora. Our data suggest that Actinobacteria may be a rich source of active compounds that can act against bacterial quorum sensing system.

  17. Biofilm Formation Derived from Ambient Air and the Characteristics of Apparatus

    International Nuclear Information System (INIS)

    Kanematsu, H; Kougo, H; Kuroda, D; Itho, H; Ogino, Y; Yamamoto, Y

    2013-01-01

    Biofilm is a kind of thin film on solidified matters, being derived from bacteria. Generally, planktonic bacteria float in aqueous environments, soil or air, most of which can be regarded as oligotrophic environments. Since they have to survive by instinct, they seek for nutrients that would exist on materials surfaces as organic matters. Therefore, bacteria attach materials surfaces reversibly. The attachment and detachment repeat for a while and finally, they attach on them irreversibly and the number of bacteria on them increases. At a threshold number, bacteria produce polymeric matters at the same time by quorum sensing mechanism and the biofilm produces on material surfaces. The biofilm produced in that way generally contains water (more than 80%), EPS (Exopolymeric Substance) and bacteria themselves. And they might bring about many industrial problems, fouling, corrosion etc. Therefore, it is very important for us to control and prevent the biofilm formation properly. However, it is generally very hard to produce biofilm experimentally and constantly in ambient atmosphere on labo scale. The authors invented an apparatus where biofilm could form on specimen's surfaces from house germs in the ambient air. In this experiment, we investigated the basic characteristics of the apparatus, reproducibility, the change of biofilm with experimental time, the quality change of water for biofilm formation and their significance for biofilm research.

  18. Kernekraft og nuklear sikkerhed 2007

    DEFF Research Database (Denmark)

    Rapporten er den femte rapport i en serie af årlige rapporter om kernekraft og nuklear sikkerhed. Rapporten er udarbejdet af medar-bejdere ved Risø DTU og Beredskabsstyrelsen. Den omhandler den internationale udvikling inden for kernekraft med særlig vægt på sikkerhedsmæssige forhold og nukleart ...... beredskab. Rapporten for 2007 dækker følgende emner: Status for kernekraftens el-produktion, regionale tendenser, reaktorudvikling, sikkerhedsrelate-rede hændelser ved kernekraft samt internationale forhold og kon-flikter.......Rapporten er den femte rapport i en serie af årlige rapporter om kernekraft og nuklear sikkerhed. Rapporten er udarbejdet af medar-bejdere ved Risø DTU og Beredskabsstyrelsen. Den omhandler den internationale udvikling inden for kernekraft med særlig vægt på sikkerhedsmæssige forhold og nukleart...

  19. Udfordringerne fra globalisering og migration:Interaktion mellem kønslighed og kulturel mangfoldighed

    OpenAIRE

    Siim, Birte

    2008-01-01

    Globalisering og migration har forøget mamgfoldighed og uligheder inden for og mellem nationerne og har skabt nye problemer for offentlige politikker og nye behov for at regulere politiske og socio-økonomiske problemer nationalt og globalt. Artiklen behandler disse udfordringer med særlig fokus på samspillet mellem køn og mangfoldighed. Det dobbelte formål er først at nyvurdere begreber om medborgerskab, nationalitet og tilhørsforhold i lyset af lokale og globale relationer og multikulturalis...

  20. Storby og religion

    DEFF Research Database (Denmark)

    Christiansen, Connie Carøe

    2014-01-01

    Det kan diskuteres, hvor bogstavelig man skal tage forudsigelsen om sekularisering eller religionens forsvindende betydning, men i dag kan en nærmere undersøgelse af livet og infrastrukturen i storbyerne bekræfte, at religion som sådan ikke er forsvundet fra byernes offentlige rum. Kan København på...

  1. Mellem lovregulering og frivillighed

    DEFF Research Database (Denmark)

    Mailand, Mikkel

    Dette notat analyserer Corporate Social Responsibility (CSR) og Virksomhedernes Sociale Engagement i tre lande. Herunder diskuteres rammebetingelsernes betydning herfor.  Diskussionen om frivillighed eller tvang er central i CSR-debatten. Analysen i notatet viser, at aktørerne i ingen af de tre...

  2. Litteraturstudie: akupunktur og palliation

    DEFF Research Database (Denmark)

    Larsen, Anne Bolt

    2013-01-01

    af systematiske søgninger fra 2002-2012 i Pubmed, Cochrane, Cinahl og PsykInfo med søgeordene acupuncture and palliation, acupuncture and cancer, acupuncture and placebo, acupuncture and neurophysiology, acupuncture and palliation and nursing. RCT-forskning viser ikke overbevisende effekt af...

  3. Hund og hensyn

    DEFF Research Database (Denmark)

    Sandøe, Peter

    2014-01-01

    Hundeloven tjener ikke til at beskytte hunde, men at beskytte mennesker mod hunde, Nu efterspørger hundeejere selv gode regler for takt og tone i det offentlige rum, ikke mindst til gavn for dem, der er bange for hunde....

  4. Retorik og reklamesprog

    DEFF Research Database (Denmark)

    Hermansen, Judy

    2009-01-01

    Den retoriske tradition definerer en retorisk figur som en "kunstnerisk afvigelse". Dvs. et udtryk, som er anderledes end det almindelige (daglig)sprog, men ikke så anderledes at det bliver forkastet som meningsløst eller forkert. lse er én af de faktorer, som skaber opmærksomhed, og meget tyder på...

  5. Valgdeltagelse og demokratisk legitimitet

    DEFF Research Database (Denmark)

    Rostbøll, Christian F.; Dabelsteen, Hans Boas

    2013-01-01

    Den meget lave deltagelse til menighedsrådsvalgene i den danske folkekirke rejser spørgsmålet, hvor vigtig høj valgdeltagelse er for demokratisk legitimitet. Artiklen diskuterer dette spørgsmål på baggrund af den politiske idehistorie og nutidens demokratiteori. Der opstilles nogle normative stan...

  6. Udeskole og elevers handlekompetence

    DEFF Research Database (Denmark)

    Breiting, Søren

    2011-01-01

    Elever elsker at komme væk fra undervisningen i skolen. Er det positivt eller negativt? Og hvad har betydning for, at eleverne får mest muligt ud af oplevelserne uden for skolen? Forskellige former for udeskole giver nogle oplagte muligheder, så eleverne udvikler sig som engagerede borgere i et...

  7. Epilepsi og orale manifestationer

    DEFF Research Database (Denmark)

    Jacobsen, Pernille Endrup; Haubek, Dorte; Østergaard, John Rosendahl

    2016-01-01

    Risiko for sygdom I mundhulen hos patienter med epilepsy Epilepsi er en kronisk neurologisk lidelse, der ofte vil kræve medicinsk behandling for at holde patienterne fri for anfald. Lidelsen kan have betydning for patientens psykosociale og kognitive udvikling, der indirekte kan have betydning...

  8. Mobning og interventioner

    DEFF Research Database (Denmark)

    Jørgensen, Stine Kaplan

    2016-01-01

    Afhandlingen ”Mobning og interventioner – positioneringsteoretiske analyser af gruppesamtaler med børn” er baseret på en empirisk undersøgelse af udvalgte interventionssamtaler, der har til hensigt at skulle reducere eller stoppe mobning. Ambitionen i afhandlingen har været at skabe indsigt i de ...

  9. Fair mulighedslighed og sundhed

    DEFF Research Database (Denmark)

    Nielsen, Lasse

    2014-01-01

    fordeling af sundhed. Og endeligt for det tredje har den svært ved at give sundhed den særstatus, som den i udgangspunktet mener, at den skal have. Det er muligt for Daniels at imødekomme disse udfordringer ved at inkorporere centrale elementer fra kapabilitetsteorien, oprindeligt udviklet af Amartya Sen. I...

  10. Tekster og sproghandlinger

    DEFF Research Database (Denmark)

    Borchmann, Simon

    2010-01-01

    Denne artikel er en sprogvidenskabelig introduktion til temaet tekst og sproghandling. Artiklen tjener dels som en beskrivelse af den historiske baggrund for temaet, dels som en argumentation for at det er relevant at behandle en bestemt problematik i relation til dette tema. Artiklen er delt i t...

  11. Handling, tekstualisering og tekst

    DEFF Research Database (Denmark)

    Togeby, Ole

    2010-01-01

    Der argumenteres her for at talehandlinger og teksthandlinger er to forskellige typer af handlinger. En talehandling er situeringen af et udsagn om et sagforhold. En teksthandling er situeringen af helheden af en række forbundne paragraffer (som er degraderede udsagn) som udgør en beskrivelse af ...

  12. Strukturreform og succeskriterier

    DEFF Research Database (Denmark)

    Pedersen, John Storm

    2006-01-01

    Strukturreformens formål er at få de offentlige institutioner til at indfri de mange succeskriterier for produktionen og leveringen af de offentlige ydelser på et højere niveau. Artiklen diskuterer om dette formål vil blive indfriet i praksis. Udgivelsesdato: 1. oktober...

  13. Mangfoldighedsledelse og internationalisering

    DEFF Research Database (Denmark)

    Lauring, Jakob; Korsgaard, Steffen

    2013-01-01

    Mangfoldighedsledelse er en ny ledelsesretning som i høj grad retter sig mod konstruktiv anvendelse af menneske­lige forskelligheder. I særlig grad er ledelsen af mangfol­dighed blevet kædet sammen med overvindelsen af kultu­relle barrierer og udnyttelsen af det læringspotentiale som ligger i opn...

  14. Branding og designmanagement

    DEFF Research Database (Denmark)

    Hermansen, Judy

    2009-01-01

      Præsentation af en brand management model, der viser, hvordan integration af design og brand management gennem hele produktudviklingsprocessen fremmer udviklingen af en konsistent brandoplevelse. Modellen er udviklet på baggrund af dybdeinterview med 37 ledere af spanske virksomheder, der er...

  15. Luhmann og Organisation

    DEFF Research Database (Denmark)

    Paulsen, Michael

    LUHMANN OG ORGANISATION Organisationsstudier spiller en særlig rolle for den tyske sociolog Niklas Luhmann (1927-1998) idet han begriber organisationer som det mest afgørende socialsystem i det moderne samfund. Kun organisati-oner kan træffe samfundsmæssige afgørelser. Faktisk begyndte Luhmann som...... organisationsteoretiker, og flere af hans tidlige værker regnes nu som milepæle indenfor organisations-studier. I 2000 udkom post humt hans sidste store organisationsteoretiske værk Organisation und Entscheidung. I Luhmanns almene systemteori trækker han kraftigt på sit kendskab til organisationer. Begribelsen af...... samtidig med, at de kan skabe en kobling mellem det moderne samfunds interaktioner og funktionssystemer. Luhmanns konstante ledetråd har været, at organisationer er det, som får samfun-det til at fungere. Uden organisationer intet moderne samfund. Luhmann og organisation henvender sig til studerende...

  16. Op og ned

    DEFF Research Database (Denmark)

    2015-01-01

    Prolog Her i 2014 færdiggøres to udsmykninger af Michael Mørk. Det ene er integreret i ny bygning til Københavns Universitet, og den anden er transformationen af den eksisterende udsmykning på Regionshospital Randers. Holdes de to projekter op mod hinanden, viser der sig tre problemstillinger, der...

  17. Robusthed, livsduelighed og karakterstyrker

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    2017-01-01

    Bogen introducerer karakterstyrker i en robustheds-kontekst. Med udgangspunkt i VIA-styrker (Values in Action) beskrives, hvad karakterstyrker er, hvorfor vi skal bruge dem og hvordan vi kan gøre det. styrkearbejdets faser gennemgås med forslag til små øvelser....

  18. Stars og striber

    DEFF Research Database (Denmark)

    Ørum, Tania

    2010-01-01

    Dansk (og nordisk) eksperimenterende kunst efter 2.verdenskrig sammenholdt med udviklingen i USA. Der er ikke blot tale om indflydelse fra amerikansk kunst til dansk, men i lige så høj grad om en selvstændig udvikling i Danmark....

  19. Religion og kognition

    DEFF Research Database (Denmark)

    Geertz, Armin W.

    2008-01-01

    Artiklen indleder et temanummer som er resultat af et udviklingskursus om kognition for religionslærerne arrangeret af Afdeling for Religionsvidenskab i samarbejde med Religionslærerforeningen. Artiklen indtroducerer emnet religion og kognition således at lærerne får indsigt i emnets væsentligste...

  20. Biologi og fremmedhad

    DEFF Research Database (Denmark)

    Sandøe, Peter

    2011-01-01

    Invasivt. Det er vigtigt at gøre sig klart, at skellet mellem de gode og de onde dyr ikke er biologisk begrundet. Det er en politisk beslutning, at vi i Danmark ønsker at fastholde en bestemt fauna....

  1. Logistiksystemer og Logistikomkostninger

    DEFF Research Database (Denmark)

    Nielsen, Steen; Mortensen, Ole

    Indlægget behandler begrebet "logistikomkostninger" sådan som disse er defineret i tysk teori. Der ses bl.a. på formålet med logistikomkostninger, hvordan de registreres, hvordan de inddrages i forskellige beslutninger og hvordan disse kan afrapporteres....

  2. Depression og placebo

    DEFF Research Database (Denmark)

    Christensen, Kaj Sparle

    2016-01-01

    Metaanalyser har længe dokumenteret, at effekten af behandling med antidepressive lægemidler er begrænset sammenlignet med effekten af placebobehandling. Antidepressive lægemidler er kun sikkert virksomme hos svært deprimerede personer. Psykoterapi og antidepressive lægemidler er lige effektive h...

  3. Augmented Reality og kulturarv

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Kirkedahl Lysholm

    2013-01-01

    Museerne står overfor at skulle omfavne den digitale kultur i håndteringen af den store mængde viden, institutionerne repræsenterer. Augmented Reality-systemer forbinder ved hjælp af moderne teknologi det virtuelle med det virkelige, og kan derfor synes som en oplagt anvendelsesmulighed i...

  4. Software og designproces

    DEFF Research Database (Denmark)

    Lykke-Olesen, Andreas

    2004-01-01

    Diskussion af hvorvidt arkitekturfaget med informationsteknologien har taget et redskab i brug, som endnu ikke er modnet og klart til brug, men som, i erkendelse af den øgede rationalisering det skaber for den videre proces i et projekt, bliver en indiskutabel konsekvens...

  5. Frihedsbevidsthed og nederlagserfaring

    DEFF Research Database (Denmark)

    Liisberg, Sune

    2005-01-01

    . Hegel. Med udgangspunkt i den tidlige modernitets filosofi (Kant, Novalis, Schopenhauer, Kierkegaard m.fl.) såvel som romankunst (Cervantes, Flaubert m. fl.) gøres der rede for frihedsbevidsthedens ansigter, idet artiklen demonstrerer en intim forbindelse imellem (moderne) frihed og (moderne) lidelse....

  6. Turisterne, naturen og nationalparken

    DEFF Research Database (Denmark)

    Kvistgaard, Peter; Smed, Karina Madsen; Møn, Team

    Møn er en turist-ø, og øens feriegæster udgør en vigtig del af naturbrugerne – såvel kvantitativt som kvalitativt. Med ca. 500.000 overnatninger pr. år er øens indbyggertal godt og vel fordoblet på et givet tidspunkt i højsæsonen, som falder sammen med den tid af året, hvor naturområderne generelt...... benyttes mest. Møns turister vælger i høj grad Møn på grund af naturen og bruger den meget. Der er stort behov for at udvikle nye oplevelsesmuligheder i den mønske natur, for at gøre dem tilgængeli-ge og informere om dem. Samtidig indebærer den store turisme selvfølgelig - selv om mange turi-ster har et......? Målgruppe er Møns turister – udvalg af interview-personer søges sammensat på nationaliteter, fami-lietyper, overnatningstyper m.v. i overensstemmelse med fordelingen i hele turistgruppen....

  7. Motivation og mismod

    DEFF Research Database (Denmark)

    Bovbjerg, Kirsten Marie; Wright, Susan; Krause-Jensen, Jakob

    I bogen gives eksempler på de situationer, hvor medarbejderne er i krydspres mellem klienter og politikere. Eller hvor deres faglige mål for arbejde ikke harmonere med ydre mål for service/kvalitet uanset om det er i skoler, kommuner eller på universiteter. Gennem feltstudier gives et indblik i m...

  8. Multitasking, myter og medier

    DEFF Research Database (Denmark)

    Aagaard, Jesper

    2014-01-01

    . Eleverne drages mod distraktion som møl mod en flamme. I denne artikel vil jeg argumentere for, at den moderne brug af informationsteknologi (IT) udfordrer klassiske psykologiske begreber som opmærksomhed og multitasking. For forstå brugen af IT, anbefaler jeg derfor et analytisk perspektivskifte, der...

  9. Frihed, anerkendelse og balance

    DEFF Research Database (Denmark)

    Anker, Thomas Boysen

    2008-01-01

    Artiklen argumenterer for, at selv ikke den absolut mest familievenlige arbejdsplads vil kunne løse det psykologiske problem med at skabe balance mellem familie og arbejdsliv, fordi ubalancen grundlæggende handler om en anerkendelseskonflikt, som individet ikke altid selv er interesseret i at komme...

  10. Forskningsdata og Open Access

    DEFF Research Database (Denmark)

    Heller, Alfred; Blaabjerg, Niels Jørgen; Clausen, Nanna Floor

    Hvilke rolle spiller forskningsbiblioteker i forhold til sikring og tilgængeliggørelse af forskningsresultater der er i form af data, visualiseringer m.m. Rapporten peger tydelig på, at bibliotekerne supplerer eksisterende aktører på området gennem deres spidskompetencer i langtidsbevaring...

  11. Fissurforsegling, SEAL og infiltrationer

    DEFF Research Database (Denmark)

    Dige, Irene

    Fissurforsegling har været en almindelig del af tandplejens behandlingsspektrum i cariesforebyggelse og -behandling siden 1970’erne. I takt med et fald i cariesforekomsten i den danske befolkning i denne periode, er der sket en ændring i indikationerne for fissurforsegling fra at være et overveje...

  12. Affaldsskakte og kildesortering

    DEFF Research Database (Denmark)

    Petersen, Lars Kjerulf; Larsen, Pernille; Friis, Pernille Bank

    Notatet afrapporterer et projekt udført for Københavns Kommune. Formålet med projektet var at undersøge affaldsskaktes betydning for kildesorteringen af husholdningsaffald i etageejendomme og for ejendommenes affaldshåndtering i det hele taget. Affaldsskaktenes betydning blev undersøgt i sammenhæ...

  13. Arkadien. Region og identitet

    DEFF Research Database (Denmark)

    Nielsen, Thomas Heine

    Oldtidens Grækenland bestod af et mylder af bystater, grupperet i regioner, og grækerne mente, at de forskellige regioners beboere havde hver deres karakteristika. Bogen undersøger dette emne nærmere i forhold til Arkadien på Peloponnes: Hvad ville det sige at være arkader? Var det et geografisk...

  14. Bystruktur og transport

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick

    2003-01-01

    Paperet præsenterer hovedkonklusionerne fra et PhD-studie af sammenhængene mellem bystruktur (særligt boliglokalisering) og transport i Aalborg. Det konkluderes at boliglokaliseringen har væsentlig betydning for transporten i det daglige. Det gælder især lokaliseringen i forhold til det samlede...

  15. Facebook og privatliv

    DEFF Research Database (Denmark)

    Nielsen, Jøren Ullits Olai

    2015-01-01

    Hvornår har vi privatliv på de sociale medier? Kan journalister frit anvende informationer fra åbne profiler på nettet, herunder personfølsomme oplysninger? Hvad hvis profilen er lukket? Betyder det, at oplysningerne ikke må anvendes, fordi de er private? Og hvis det er tilfældet, er profilen så ...

  16. Global Analysis of the Burkholderia thailandensis Quorum Sensing-Controlled Regulon

    OpenAIRE

    Majerczyk, Charlotte; Brittnacher, Mitchell; Jacobs, Michael; Armour, Christopher D.; Radey, Mathew; Schneider, Emily; Phattarasokul, Somsak; Bunt, Richard; Greenberg, E. Peter

    2014-01-01

    Burkholderia thailandensis contains three acyl-homoserine lactone quorum sensing circuits and has two additional LuxR homologs. To identify B. thailandensis quorum sensing-controlled genes, we carried out transcriptome sequencing (RNA-seq) analyses of quorum sensing mutants and their parent. The analyses were grounded in the fact that we identified genes coding for factors shown previously to be regulated by quorum sensing among a larger set of quorum-controlled genes. We also found that gene...

  17. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.; Vrouwenvelder, Johannes S.; Paulitsch-Fuchs, Astrid H.; Zwijnenburg, Arie; Kruithof, Joop C.; Flemming, Hans Curt

    2013-01-01

    resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric

  18. Progression og underviserkompetencer

    Directory of Open Access Journals (Sweden)

    Lene Tortzen Bager

    2014-03-01

    Full Text Available På baggrund af en kvalitativ interviewundersøgelse af undervisere ved Aarhus Universitet lavet i 2012, tematiserer artiklen, hvordan undervisere udvikler deres faglige og pædagogiske kompetencer i forhold til at kunne skabe progression inden for innovation og entreprenørskab forstået enten som didaktik, arbejdsformer i faglige forløb eller som fag på universitetet. I arbejdet med progression er det en udfordring at integrere de nye faglige dimensioner i det kernefaglige felt. Den seneste model for progression inden for innovation og entreprenør-skab siger, at det er den lærendes generelle erfaringsniveau, der er den afgørende progressionsskabende faktor (Progressionsmodellen, Fonden for Entreprenørskab, 2013b. Samtidig skelner international forskning inden for studiekompetenceområdet mellem niveauer, hvor indlejret viden er det mest avancerede kompetenceniveau (Barrie, 2002.Ifølge progressionsmodellen og den nævnte kompetenceforskning er erfaring og dybt integreret læring altså centrale dimensioner i progression. Men hvad er underviserens rolle heri? Underviserens professionelle udviklingsarbejde forekommer at være underbelyst i forhold til, at underviseren er den legitime garant for integrationen af nye faglige dimensioner og for den studerendes kompetenceniveau. Interviewundersøgelsen forholder sig til spørgsmålet om progression gennem de deltagende underviseres beskrivelse af betydningslag i entreprenørskabsbegrebet koblet til de praksisformer i undervisningen, der knytter sig hertil samt et indblik i undervisernes refleksioner over deres kompetenceudviklingsprocesser. Artiklens bidrag til progression er at se underviserens motivation og kompetenceudvikling som forudsætninger herfor.     Based on a qualitative study of five teachers in the Faculty of Arts at Aarhus University that took place during 2012, the article thematizes how teachers develop their professional and educational qualifications in innovation and

  19. Digital portfolio og peer to peer feedback

    DEFF Research Database (Denmark)

    Jacobsen, Ditte; Bahrenscheer, Jesper Glarborg

    2017-01-01

    studerende og øget transfer mellem teori og praksis. Artiklen tager afsæt i erfaringerne fra udvikling, anvendelse og evaluering af den digitale portfolio og peer to peer feedback. Portfolien er digital og tilknyttet Metropols Learning Management System. De studerende uploader individuelt ugentligt deres...

  20. Arkitektur krop og læring

    DEFF Research Database (Denmark)

    Gulløv, E.; Coninck-Smith, N. D.; Pedersen, S. H.

    på teori og empiri fra sociologi, pædagogik, filosofi og arkitektur, er skrevet af førende danske, norske og svenske forskere inden for dette relativt nye tværfaglige forskningsområde. Det er særligt Bourdieu og Foucault der inddrages, men også Lefebvre, Latour, Gibson, Bernstein, Elias, Eichberg...