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Sample records for bacterial porin disrupts

  1. Bacterial porin disrupts mitochondrial membrane potential and sensitizes host cells to apoptosis.

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    Vera Kozjak-Pavlovic

    2009-10-01

    Full Text Available The bacterial PorB porin, an ATP-binding beta-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (DeltaPsi(m. Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of beta-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of DeltaPsi(m. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce DeltaPsi(m loss and apoptosis, demonstrating that dissipation of DeltaPsi(m is a requirement for cell death caused by neisserial infection.

  2. Function and modulation of bacterial porins: insights from electrophysiology.

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    Delcour, A H

    1997-06-15

    Electrophysiological techniques provide a wealth of information regarding the molecular mechanisms that underlie the function and modulation of ion channels. They have revealed that bacterial porins do not behave as static, permanently open pores but display a much more complex and dynamic behavior than anticipated from non-electrophysiological studies. The channels switch between short-lived open and closed conformations (gating activity), and can also remain in an inactivated, non-ion conducting state for prolonged periods of time. Thus the role of porins is not limited to that of a molecular filter, but is extended to the control of outer membrane permeability through the regulation of their activity. Electrophysiological studies have indeed demonstrated that both gating and inactivation are modulated by a variety of physical and chemical parameters and are highly cooperative phenomena, often involving numerous channels working in concert. Cooperativity acts as an amplification mechanism that grants a large population of porins, such as found in the outer membrane, with sensitivity to modulation by external or internal factors. By conferring permeability properties to the outer membrane, porins play a crucial role in the bacterium's antibiotic susceptibility and survival in various environmental conditions. The detailed information that electrophysiology only can provide on porin function and modulation promises to yield a more accurate description of how porin properties can be used by cells to adapt to a changing environment, and to offer mechanisms that might optimize the drug sensitivity of the microorganism. PMID:9228742

  3. Genomic Analyses of Bacterial Porin-Cytochrome Gene Clusters

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    Liang eShi

    2014-11-01

    Full Text Available The porin-cytochrome (Pcc protein complex is responsible for trans-outer membrane electron transfer during extracellular reduction of Fe(III by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens PCA. The identified and characterized Pcc complex of G. sulfurreducens PCA consists of a porin-like outer-membrane protein, a periplasmic 8-heme c-type cytochrome (c-Cyt and an outer-membrane 12-heme c-Cyt, and the genes encoding the Pcc proteins are clustered in the same regions of genome (i.e., the pcc gene clusters of G. sulfurreducens PCA. A survey of additionally microbial genomes has identified the pcc gene clusters in all sequenced Geobacter spp. and other bacteria from six different phyla, including Anaeromyxobacter dehalogenans 2CP-1, A. dehalogenans 2CP-C, Anaeromyxobacter sp. K, Candidatus Kuenenia stuttgartiensis, Denitrovibrio acetiphilus DSM 12809, Desulfurispirillum indicum S5, Desulfurivibrio alkaliphilus AHT2, Desulfurobacterium thermolithotrophum DSM 11699, Desulfuromonas acetoxidans DSM 684, Ignavibacterium album JCM 16511, and Thermovibrio ammonificans HB-1. The numbers of genes in the pcc gene clusters vary, ranging from two to nine. Similar to the metal-reducing (Mtr gene clusters of other Fe(III-reducing bacteria, such as Shewanella spp., additional genes that encode putative c-Cyts with predicted cellular localizations at the cytoplasmic membrane, periplasm and outer membrane often associate with the pcc gene clusters. This suggests that the Pcc-associated c-Cyts may be part of the pathways for extracellular electron transfer reactions. The presence of pcc gene clusters in the microorganisms that do not reduce solid-phase Fe(III and Mn(IV oxides, such as D. alkaliphilus AHT2 and I. album JCM 16511, also suggests that some of the pcc gene clusters may be involved in extracellular electron transfer reactions with the substrates other than Fe(III and Mn(IV oxides.

  4. Porins increase copper susceptibility of Mycobacterium tuberculosis.

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    Speer, Alexander; Rowland, Jennifer L; Haeili, Mehri; Niederweis, Michael; Wolschendorf, Frank

    2013-11-01

    Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increases tolerance for copper at elevated concentrations, indicating that porins mediate copper uptake across the outer membrane. Heterologous expression of the mycobacterial porin gene mspA reduced growth of M. tuberculosis in the presence of 2.5 μM copper by 40% and completely suppressed growth at 15 μM copper, while wild-type M. tuberculosis reached its normal cell density at that copper concentration. Moreover, the polyamine spermine, a known inhibitor of porin activity in Gram-negative bacteria, enhanced tolerance of M. tuberculosis for copper, suggesting that copper ions utilize endogenous outer membrane channel proteins of M. tuberculosis to gain access to interior cellular compartments. In summary, these findings highlight the outer membrane as the first barrier against copper ions and the role of porins in mediating copper uptake in M. smegmatis and M. tuberculosis. PMID:24013632

  5. New Findings Concerning Vertebrate Porin

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    Thinnes, Friedrich P.; Reymann, Susanne

    Eukaryotic porin can be considered to be a good candidate for forming the channel component of the protein complex which, depending on the approach used, may realize its expression either as the outwardly-rectifying depolarization-induced chloride channel or as the volume-sensitive organic osmolyte-anion channel. As a basis for this proposition, we point to a series of correspondences in properties between mammalian porin and the ORDIC channel complex. Specifically, mammalian porin is expressed in the plasmalemma of different cells and chloride channels can be blocked by anti-human porin antibodies in astrocytes and endothelial cells. There is an indication of colocalisation of human porin and the cystic fibrosis (CF) gene product, CFTR, in the apical region of epithelial cells. The primary structure of porin from a CF patient was found to be normal. Cytosol and amniotic fluid fractions influence the channel characteristics of mammalian porin. Channel-active mammalian porin binds ATP and the stilbene disulphonate grouping of the chloride channel inhibitor DIDS. Human porin in black membranes is a pathway for taurine, and biogenic polyamines reduce the voltage dependence of human porin. Assuming the relationship between human porin and the ORDIC channel/VSOAC complex, studies on plasmalemma-integrated human porin have a relevance for CF research. In addition, we refer to a case study on a child with encephalomyopathy in which porin could not be detected using monoclonal anti-human porin antibodies. Our studies were based on purified and sequenced human porin from different cells and from different cell compartments. In addition, we raised antibodies against mature human porin or synthetic parts of the molecule. This provided a firm foundation for our topochemical work with which we were able to establish the multi-topological expression of eukaryotic porin channels. The data are summarized and discussed.

  6. Porins Increase Copper Susceptibility of Mycobacterium tuberculosis

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    Speer, Alexander; Rowland, Jennifer L.; Haeili, Mehri; Niederweis, Michael; Wolschendorf, Frank

    2013-01-01

    Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increas...

  7. Mucosal immunization with the Moraxella catarrhalis porin m35 induces enhanced bacterial clearance from the lung: a possible role for opsonophagocytosis

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    Donna eEaston

    2011-05-01

    Full Text Available Moraxella catarrhalis is a significant cause of respiratory tract infection against which a vaccine is sought. Several outer membrane proteins are currently under investigation as potential vaccine antigens, including the porin M35. We have previously shown that the third external loop of M35 was immunodominant over the remainder of the protein for antibody produced in mice against the refolded recombinant protein. However, as this loop is predicted to fold inside the porin channel we also predicted that it would not be accessible to these antibodies when M35 is expressed on the surface of the bacteria in its native conformation. This study investigated the functional activity of antibodies against M35 and those specific for the loop 3 region of M35 in vitro and in vivo. Antisera from mice immunized with M35 or the loop 3-deletion, M35loop3–, recombinant proteins were not bactericidal but did have enhanced opsonic activity, whereas antibodies raised against the loop 3 peptide were not opsonising indicating that the immunodominant loop 3 of M35 was not accessible to antibody as we had previously predicted. Mucosal immunization with M35, M35 that had an antigenically altered loop 3 (M35(ID78 and M35loop3– enhanced the clearance of M. catarrhalis from the lungs of mice challenged with live M. catarrhalis. The in vivo clearance of bacteria in the mice with the M35-derived protein constructs correlated significantly (p<0.001 with the opsonic activity assessed an in vitro opsonophagocytosis assay. This study has demonstrated that the immunodominat B-cell epitope to loop 3 of the M. catarrhalis outer membrane protein M35 is not associated with immune protection and that M35-specific antibodies are not bactericidal but are opsonising. The opsonising activity correlated with in vivo clearance of the bacteria suggesting that opsonising antibody may be a good correlate of immune protection.

  8. HYDRAULIC DISRUPTION AND PASSIVE MIGRATION BY A BACTERIAL PATHOGEN IN OAK TREE XYLEM

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    Xylella fastidiosa (Xf) is a xylem-limited bacterial pathogen that causes leaf scorch symptoms in numerous host plant species in urban, agricultural, and natural ecosystems worldwide. The exact mechanism of hydraulic disruption and systemic colonization of xylem by Xf remains elusive across all hos...

  9. Synthesis of antimicrobial cyclodextrins bearing polyarylamino and polyalkylamino groups via click chemistry for bacterial membrane disruption.

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    Yamamura, Hatsuo; Sugiyama, Yuuki; Murata, Kensuke; Yokoi, Takanori; Kurata, Ryuji; Miyagawa, Atsushi; Sakamoto, Kenji; Komagoe, Keiko; Inoue, Tsuyoshi; Katsu, Takashi

    2014-05-28

    Cyclodextrin derivatives are synthesized as membrane-disrupting agents via a microwave-assisted Huisgen reaction. Their ability to permeabilize bacterial membranes depends on the amino substituents and an appropriate balance of hydrophobicity and hydrophilicity, thus enabling the preparation of derivatives with selective toxicity against bacteria.

  10. Ability of chitosan gels to disrupt bacterial biofilms and their applications in the treatment of bacterial vaginosis.

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    Kandimalla, Karunya K; Borden, Emma; Omtri, Rajesh S; Boyapati, Siva Prasad; Smith, Michael; Lebby, Kimberly; Mulpuru, Maanavi; Gadde, Mounika

    2013-07-01

    Recurrence of bacterial vaginosis is attributed to the inability of various formulations to disrupt bacterial biofilms. A negatively charged polysaccharide matrix coats the bacterial communities in the biofilm and restricts the penetration of antibiotics. Therefore, bacteria in the deeper segments of the biofilm persist and perpetuate the infection. In this study, we have tested the efficacy of two bioadhesive polymers, cationic chitosan and anionic polycarbophil, to disrupt Pseudomonas aeruginosa biofilms grown in the Center for Disease Control bioreactor as well as on the 96-well plates. The biofilms were treated with various concentrations of polycarbophil and chitosan at pH 4 or 6. Biofilm integrity following various treatments was evaluated by crystal violet stain and laser confocal microscopy employing Syto9 (live-cell stain) and propidium iodide (dead-cell stain). These studies demonstrated that chitosan gel disrupts the P. aeruginosa biofilm more effectively than does polycarbophil; and this effect is independent of the pH and charge densities on either polymers.

  11. How beta-lactam antibiotics enter bacteria: a dialogue with the porins.

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    Chloë E James

    Full Text Available BACKGROUND: Multi-drug resistant (MDR infections have become a major concern in hospitals worldwide. This study investigates membrane translocation, which is the first step required for drug action on internal bacterial targets. beta-lactams, a major antibiotic class, use porins to pass through the outer membrane barrier of Gram-negative bacteria. Clinical reports have linked the MDR phenotype to altered membrane permeability including porin modification and efflux pump expression. METHODOLOGY/PRINCIPAL FINDINGS: Here influx of beta-lactams through the major Enterobacter aerogenes porin Omp36 is characterized. Conductance measurements through a single Omp36 trimer reconstituted into a planar lipid bilayer allowed us to count the passage of single beta-lactam molecules. Statistical analysis of each transport event yielded the kinetic parameters of antibiotic travel through Omp36 and distinguishable translocation properties of beta-lactams were quantified for ertapenem and cefepime. Expression of Omp36 in an otherwise porin-null bacterial strain is shown to confer increases in the killing rate of these antibiotics and in the corresponding bacterial susceptibility. CONCLUSIONS/SIGNIFICANCE: We propose the idea of a molecular "passport" that allows rapid transport of substrates through porins. Deciphering antibiotic translocation provides new insights for the design of novel drugs that may be highly effective at passing through the porin constriction zone. Such data may hold the key for the next generation of antibiotics capable of rapid intracellular accumulation to circumvent the further development MDR infections.

  12. Drosophila Porin/VDAC affects mitochondrial morphology.

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    Jeehye Park

    Full Text Available Voltage-dependent anion channel (VDAC has been suggested to be a mediator of mitochondrial-dependent cell death induced by Ca(2+ overload, oxidative stress and Bax-Bid activation. To confirm this hypothesis in vivo, we generated and characterized Drosophila VDAC (porin mutants and found that Porin is not required for mitochondrial apoptosis, which is consistent with the previous mouse studies. We also reported a novel physiological role of Porin. Loss of porin resulted in locomotive defects and male sterility. Intriguingly, porin mutants exhibited elongated mitochondria in indirect flight muscle, whereas Porin overexpression produced fragmented mitochondria. Through genetic analysis with the components of mitochondrial fission and fusion, we found that the elongated mitochondria phenotype in porin mutants were suppressed by increased mitochondrial fission, but enhanced by increased mitochondrial fusion. Furthermore, increased mitochondrial fission by Drp1 expression suppressed the flight defects in the porin mutants. Collectively, our study showed that loss of Drosophila Porin results in mitochondrial morphological defects and suggested that the defective mitochondrial function by Porin deficiency affects the mitochondrial remodeling process.

  13. Monoclonal antibodies against DNA-binding tips of DNABII proteins disrupt biofilms in vitro and induce bacterial clearance in vivo

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    Laura A. Novotny

    2016-08-01

    Full Text Available The vast majority of chronic and recurrent bacterial diseases are attributed to the presence of a recalcitrant biofilm that contributes significantly to pathogenesis. As such, these diseases will require an innovative therapeutic approach. We targeted DNABII proteins, an integral component of extracellular DNA (eDNA which is universally found as part of the pathogenic biofilm matrix to develop a biofilm disrupting therapeutic. We show that a cocktail of monoclonal antibodies directed against specific epitopes of a DNABII protein is highly effective to disrupt diverse biofilms in vitro as well as resolve experimental infection in vivo, in both a chinchilla and murine model. Combining this monoclonal antibody cocktail with a traditional antibiotic to kill bacteria newly released from the biofilm due to the action of the antibody cocktail was highly effective. Our results strongly support these monoclonal antibodies as attractive candidates for lead optimization as a therapeutic for resolution of bacterial biofilm diseases.

  14. Targeted and random bacterial gene disruption using a group II intron (targetron) vector containing a retrotransposition-activated selectable marker

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    Zhong, Jin; Karberg, Michael; Lambowitz, Alan M.

    2003-01-01

    Mobile group II introns have been used to develop a novel class of gene targeting vectors, targetrons, which employ base pairing for DNA target recognition and can thus be programmed to insert into any desired target DNA. Here, we have developed a targetron containing a retrotransposition-activated selectable marker (RAM), which enables one-step bacterial gene disruption at near 100% efficiency after selection. The targetron can be generated via PCR without cloning, and after intron integrati...

  15. Architecture of beta-barrel membrane proteins: analysis of trimeric porins.

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    Seshadri, K.; Garemyr, R.; Wallin, E.; von Heijne, G; Elofsson, A.

    1998-01-01

    We have analyzed the known three-dimensional structures of trimeric porins from bacterial outer membranes. The distribution of surface-exposed residues in a direction perpendicular to the membrane is similar to that in helical membrane proteins, with aliphatic residues concentrated in the central 20 A of the bilayer. Outside these residues is a layer of aromatic residues, followed by polar and charged residues. Residues in the trimer interface are more conserved than residues not in the inter...

  16. Effect of phenol-induced changes in lipid composition on conformation of OmpF-like porin of Yersinia pseudotuberculosis.

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    Sanina, Nina; Nina, Sanina; Davydova, Ludmila; Ludmila, Davydova; Bakholdina, Svetlana; Svetlana, Bakholdina; Novikova, Olga; Olga, Novikova; Pornyagina, Olga; Olga, Pornyagina; Solov'eva, Tamara; Tamara, Solov'eva; Shnyrov, Valery; Valery, Shnyrov; Bogdanov, Mikhail; Mikhail, Bogdanov

    2013-07-11

    The present work aimed to compare the effects of different lysophosphatidylethanolamine (LPE) content in lipids derived from Yersinia pseudotuberculosis cells exposed and not exposed to phenol on the conformation of OmpF-like porin of these bacteria. Differential scanning calorimetry and intrinsic protein fluorescence showed that the 2.5-fold increase of LPE content and the corresponding increase in the phase transition temperature of bacterial lipids were accompanied by enhanced protein thermostability. Integral conformational rearrangement of protein was supported by drastic changes in the microenvironment of the tryptophan residues, likely resulting in a convergence of monomers in trimeric porin and exposure of outer tryptophan residues to the water environment. These conformational changes may impede the porin channel permeability under stress conditions in bacteria. PMID:23742936

  17. The evolutionary history of mitochondrial porins

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    Hausner Georg

    2007-02-01

    Full Text Available Abstract Background Mitochondrial porins, or voltage-dependent anion-selective channels (VDAC allow the passage of small molecules across the mitochondrial outer membrane, and are involved in complex interactions regulating organellar and cellular metabolism. Numerous organisms possess multiple porin isoforms, and initial studies indicated an intriguing evolutionary history for these proteins and the genes that encode them. Results In this work, the wealth of recent sequence information was used to perform a comprehensive analysis of the evolutionary history of mitochondrial porins. Fungal porin sequences were well represented, and newly-released sequences from stramenopiles, alveolates, and seed and flowering plants were analyzed. A combination of Neighbour-Joining and Bayesian methods was used to determine phylogenetic relationships among the proteins. The aligned sequences were also used to reassess the validity of previously described eukaryotic porin motifs and to search for signature sequences characteristic of VDACs from plants, animals and fungi. Secondary structure predictions were performed on the aligned VDAC primary sequences and were used to evaluate the sites of intron insertion in a representative set of the corresponding VDAC genes. Conclusion Our phylogenetic analysis clearly shows that paralogs have appeared several times during the evolution of VDACs from the plants, metazoans, and even the fungi, suggesting that there are no "ancient" paralogs within the gene family. Sequence motifs characteristic of the members of the crown groups of organisms were identified. Secondary structure predictions suggest a common 16 β-strand framework for the transmembrane arrangement of all porin isoforms. The GLK (and homologous or analogous motifs and the eukaryotic porin motifs in the four representative Chordates tend to be in exons that appear to have changed little during the evolution of these metazoans. In fact there is phase

  18. Role of porins for uptake of antibiotics by Mycobacterium smegmatis.

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    Danilchanka, Olga; Pavlenok, Mikhail; Niederweis, Michael

    2008-09-01

    The outer membrane of mycobacteria presents an effective permeability barrier for many antibiotics. Transport pathways across this membrane are unknown for most drugs. Here, we examined which antibiotics utilize the porin pathway across the outer membrane of the model organism Mycobacterium smegmatis. Deletion of the porins MspA and MspC drastically increased the resistance of M. smegmatis ML10 to beta-lactam antibiotics, while its beta-lactamase activity remained unchanged. These results are consistent with the ninefold-reduced outer membrane permeability of the M. smegmatis porin mutants for cephaloridine and strongly indicate that beta-lactam antibiotics rely on the porin pathway. The porin mutant ML10 accumulated less chloramphenicol and norfloxacin and was less susceptible to these antibiotics than wild-type M. smegmatis. These results demonstrated that small and hydrophilic antibiotics use the Msp porins for entering the cell. In contrast to norfloxacin, the hydrophobic moxifloxacin was 32-fold more effective in inhibiting the growth of M. smegmatis, presumably because it was able to diffuse through the lipid membrane. Structural models indicated that erythromycin, kanamycin, and vancomycin are too large to move through the MspA channel. This study presents the first experimental evidence that hydrophilic fluoroquinolones and chloramphenicol diffuse through porins in mycobacteria. Thus, mutations resulting in less efficient porins or lower porin expression levels are likely to represent a mechanism for the opportunistic pathogens M. avium, M. chelonae, and M. fortuitum, which have Msp-like porins, to acquire resistance to fluoroquinolones. PMID:18559650

  19. On the determining role of network structure titania in silicone against bacterial colonization: Mechanism and disruption of biofilm

    Energy Technology Data Exchange (ETDEWEB)

    Depan, D.; Misra, R.D.K., E-mail: dmisra@louisiana.edu

    2014-01-01

    Silicone-based biomedical devices are prone to microbial adhesion, which is the primary cause of concern in the functioning of the artificial device. Silicone exhibiting long-term and effective antibacterial ability is highly desirable to prevent implant related infections. In this regard, nanophase titania was incorporated in silicone as an integral part of the silicone network structure through cross-link mechanism, with the objective to reduce bacterial adhesion to a minimum. The bacterial adhesion was studied using crystal violet assay, while the mechanism of inhibition of biofilm formation was studied via electron microscopy. The incorporation of nanophase titania in silicone dramatically reduced the viability of Staphylococcus aureus (S. aureus) and the capability to adhere on the surface of hybrid silicone by ∼ 93% in relation to stand alone silicone. The conclusion of dramatic reduction in the viability of S. aureus is corroborated by different experimental approaches including biofilm inhibition assay, zone of inhibition, and through a novel experiment that involved incubation of biofilm with titania nanoparticles. It is proposed that the mechanism of disruption of bacterial film in the presence of titania involves puncturing of the bacterial cell membrane. - Highlights: • Network structure titania in silicone imparts antimicrobial activity. • Ability to microbial adhesion is significantly reduced. • Antimicrobial mechanism involves rupture of biofilm.

  20. Multidrug Resistance of a Porin Deletion Mutant of Mycobacterium smegmatis

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    Stephan, Joachim; Mailaender, Claudia; Etienne, Gilles; Daffé, Mamadou; Niederweis, Michael

    2004-01-01

    Mycobacteria contain an outer membrane of unusually low permeability which contributes to their intrinsic resistance to many agents. It is assumed that small and hydrophilic antibiotics cross the outer membrane via porins, whereas hydrophobic antibiotics may diffuse through the membrane directly. A mutant of Mycobacterium smegmatis lacking the major porin MspA was used to examine the role of the porin pathway in antibiotic sensitivity. Deletion of the mspA gene caused high-level resistance of...

  1. Peptides complementary to the active loop of porin P2 from Haemophilus influenzae modulate its activity

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    Galdiero S

    2012-05-01

    Full Text Available Marco Cantisani,1 Mariateresa Vitiello,2 Annarita Falanga,1 Emiliana Finamore,2 Marilena Galdiero,2 Stefania Galdiero11Department of Biological Sciences, CIRPeB and IBB CNR, University of Naples "Federico II," Napoli, Italy; 2Department of Experimental Medicine, II University of Naples, Napoli, ItalyAbstract: Haemophilus influenzae type b (Hib is one of the leading causes of invasive bacterial infection in young children. It is characterized by inflammation that is mainly mediated by cytokines and chemokines. One of the most abundant components of the Hib outer membrane is the P2 porin, which has been shown to induce the release of several inflammatory cytokines. A synthetic peptide corresponding to loop L7 of the porin activates JNK and p38 mitogen-activated protein kinase (MAPK pathways. We report a novel use of the complementary peptide approach to design a peptide that is able to bind selectively to the protein P2, thereby reducing its activity. This work provides insights into essential molecular details of P2 that may affect the pathogenesis of Hib infections where interruption of the signaling cascade could represent an attractive therapeutic strategy.Keywords: complementary-peptide, rational design, porin

  2. Structure-Activity Relationship of Amino Acid Tunable Lipidated Norspermidine Conjugates: Disrupting Biofilms with Potent Activity against Bacterial Persisters.

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    Konai, Mohini M; Adhikary, Utsarga; Samaddar, Sandip; Ghosh, Chandradhish; Haldar, Jayanta

    2015-12-16

    The emergence of bacterial resistance and biofilm associated infections has created a challenging situation in global health. In this present state of affairs where conventional antibiotics are falling short of being able to provide a solution to these problems, development of novel antibacterial compounds possessing the twin prowess of antibacterial and antibiofilm efficacy is imperative. Herein, we report a library of amino acid tunable lipidated norspermidine conjugates that were prepared by conjugating both amino acids and fatty acids with the amine functionalities of norspermidine through amide bond formation. These lipidated conjugates displayed potent antibacterial activity against various planktonic Gram-positive and Gram-negative bacteria including drug-resistant superbugs such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and β-lactam-resistant Klebsiella pneumoniae. This class of nontoxic and fast-acting antibacterial molecules (capable of killing bacteria within 15 min) did not allow bacteria to develop resistance against them after several passages. Most importantly, an optimized compound in the series was also capable of killing metabolically inactive persisters and stationary phase bacteria. Additionally, this compound was capable of disrupting the preformed biofilms of S. aureus and E. coli. Therefore, this class of antibacterial conjugates have potential in tackling the challenging situation posed by both bacterial resistance as well as drug tolerance due to biofilm formation. PMID:26452096

  3. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior.

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    Beltrán-Partida, Ernesto; Valdez-Salas, Benjamín; Escamilla, Alan; Curiel, Mario; Valdez-Salas, Ernesto; Nedev, Nicola; Bastidas, Jose M

    2016-03-01

    Amorphous titanium dioxide (TiO2) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability.

  4. Bacterial cytolysin during meningitis disrupts the regulation of glutamate in the brain, leading to synaptic damage.

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    Carolin Wippel

    Full Text Available Streptococcus pneumoniae (pneumococcal meningitis is a common bacterial infection of the brain. The cholesterol-dependent cytolysin pneumolysin represents a key factor, determining the neuropathogenic potential of the pneumococci. Here, we demonstrate selective synaptic loss within the superficial layers of the frontal neocortex of post-mortem brain samples from individuals with pneumococcal meningitis. A similar effect was observed in mice with pneumococcal meningitis only when the bacteria expressed the pore-forming cholesterol-dependent cytolysin pneumolysin. Exposure of acute mouse brain slices to only pore-competent pneumolysin at disease-relevant, non-lytic concentrations caused permanent dendritic swelling, dendritic spine elimination and synaptic loss. The NMDA glutamate receptor antagonists MK801 and D-AP5 reduced this pathology. Pneumolysin increased glutamate levels within the mouse brain slices. In mouse astrocytes, pneumolysin initiated the release of glutamate in a calcium-dependent manner. We propose that pneumolysin plays a significant synapto- and dendritotoxic role in pneumococcal meningitis by initiating glutamate release from astrocytes, leading to subsequent glutamate-dependent synaptic damage. We outline for the first time the occurrence of synaptic pathology in pneumococcal meningitis and demonstrate that a bacterial cytolysin can dysregulate the control of glutamate in the brain, inducing excitotoxic damage.

  5. Disruption of Bacterial Cells by Photocatalysis of Montmorillonite Supported Titanium Dioxide

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    LEI Shaomin; GUO Gaoli; XIONG Bihua; GONG Wenqi; MEI Guangjun

    2009-01-01

    The photo-induced antibacterial capacity of montmorillonite supported titanium dioxide(TiO_2/Mmt for short)was evaluated by using Escherichia coli and Staphylococcus aureus as modal organisms.The bactericidal activity of TiO_2/Mmt was examined by cell viability assay under different illumination modes.Atomic force microscopy(AFM)and total organic carbon/Total nitrogen (TOC/TN)analyses were employed to investigate the mechanism of the photocatalytic bactericidal process qualitatively and quantitatively.The kinetic data show that TiO_2/Mmt has excellent antibac-terial performance,and about 99%of both bacteria cells are inactivated within 75 min illumination.The AFM images demonstrate that the bacterial cells are irreversibly decomposed and some cell components are dissolved.Therefore,the content and phase of carbon and nitrogen in the solution are changed after photocatalytic reaction.

  6. Porin seudun jätepoliittisen ohjelman valmistelu

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    Isonokari, Hanna

    2013-01-01

    Opinnäytetyön tarkoituksena oli valmistella Porin seudun jätepoliittista ohjelmaa kartoittamalla Porin seudun jätehuollon nykytilaa sekä tulevaisuuden kehittämistarpeita. Opinnäytetyön tilaaja, Porin seudun jätelautakunta, laatii jätepoliittisen ohjelman vuoden 2013 aikana. Ohjelma on jätelautakuntaan kuuluvien kahdeksan kunnan yhteinen näkemys siitä, mihin suuntaan jätehuoltoa alueella kehitetään. Opinnäytetyössä käsitellään jätehuollon nykytilaa valtakunnallisesti ja alueellisesti sekä j...

  7. Importance of Porins for Biocide Efficacy against Mycobacterium smegmatis▿

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    Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

    2011-01-01

    Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N′-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides. PMID:21398489

  8. Importance of porins for biocide efficacy against Mycobacterium smegmatis.

    Science.gov (United States)

    Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

    2011-05-01

    Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N'-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides. PMID:21398489

  9. Porins facilitate nitric oxide-mediated killing of mycobacteria.

    Science.gov (United States)

    Fabrino, Daniela Leite; Bleck, Christopher K E; Anes, Elsa; Hasilik, Andrej; Melo, Rossana C N; Niederweis, Michael; Griffiths, Gareth; Gutierrez, Maximiliano Gabriel

    2009-09-01

    Non-pathogenic mycobacteria such us Mycobacterium smegmatis reside in macrophages within phagosomes that fuse with late endocytic/lysosomal compartments. This sequential fusion process is required for the killing of non-pathogenic mycobacteria by macrophages. Porins are proteins that allow the influx of hydrophilic molecules across the mycobacterial outer membrane. Deletion of the porins MspA, MspC and MspD significantly increased survival of M. smegmatis in J774 macrophages. However, the mechanism underlying this observation is unknown. Internalization of wild-type M. smegmatis (SMR5) and the porin triple mutant (ML16) by macrophages was identical indicating that the viability of the porin mutant in vivo was enhanced. This was not due to effects on phagosome trafficking since fusion of phagosomes containing the mutant with late endocytic compartments was unaffected. Moreover, in ML16-infected macrophages, the generation of nitric oxide (NO) was similar to the wild type-infected cells. However, ML16 was significantly more resistant to the effects of NO in vitro compared to SMR5. Our data provide evidence that porins render mycobacteria vulnerable to killing by reactive nitrogen intermediates within phagosomes probably by facilitating uptake of NO across the mycobacterial outer membrane. PMID:19460455

  10. Large-Conductance Transmembrane Porin Made from DNA Origami.

    Science.gov (United States)

    Göpfrich, Kerstin; Li, Chen-Yu; Ricci, Maria; Bhamidimarri, Satya Prathyusha; Yoo, Jejoong; Gyenes, Bertalan; Ohmann, Alexander; Winterhalter, Mathias; Aksimentiev, Aleksei; Keyser, Ulrich F

    2016-09-27

    DNA nanotechnology allows for the creation of three-dimensional structures at nanometer scale. Here, we use DNA to build the largest synthetic pore in a lipid membrane to date, approaching the dimensions of the nuclear pore complex and increasing the pore-area and the conductance 10-fold compared to previous man-made channels. In our design, 19 cholesterol tags anchor a megadalton funnel-shaped DNA origami porin in a lipid bilayer membrane. Confocal imaging and ionic current recordings reveal spontaneous insertion of the DNA porin into the lipid membrane, creating a transmembrane pore of tens of nanosiemens conductance. All-atom molecular dynamics simulations characterize the conductance mechanism at the atomic level and independently confirm the DNA porins' large ionic conductance. PMID:27504755

  11. Bacterial niche-specific genome expansion is coupled with highly frequent gene disruptions in deep-sea sediments.

    Directory of Open Access Journals (Sweden)

    Yong Wang

    Full Text Available The complexity and dynamics of microbial metagenomes may be evaluated by genome size, gene duplication and the disruption rate between lineages. In this study, we pyrosequenced the metagenomes of microbes obtained from the brine and sediment of a deep-sea brine pool in the Red Sea to explore the possible genomic adaptations of the microbes in response to environmental changes. The microbes from the brine and sediments (both surface and deep layers of the Atlantis II Deep brine pool had similar communities whereas the effective genome size varied from 7.4 Mb in the brine to more than 9 Mb in the sediment. This genome expansion in the sediment samples was due to gene duplication as evidenced by enrichment of the homologs. The duplicated genes were highly disrupted, on average by 47.6% and 70% for the surface and deep layers of the Atlantis II Deep sediment samples, respectively. The disruptive effects appeared to be mainly due to point mutations and frameshifts. In contrast, the homologs from the Atlantis II Deep brine sample were highly conserved and they maintained relatively small copy numbers. Likely, the adaptation of the microbes in the sediments was coupled with pseudogenizations and possibly functional diversifications of the paralogs in the expanded genomes. The maintenance of the pseudogenes in the large genomes is discussed.

  12. Bacterial niche-specific genome expansion is coupled with highly frequent gene disruptions in deep-sea sediments

    KAUST Repository

    Wang, Yong

    2011-12-21

    The complexity and dynamics of microbial metagenomes may be evaluated by genome size, gene duplication and the disruption rate between lineages. In this study, we pyrosequenced the metagenomes of microbes obtained from the brine and sediment of a deep-sea brine pool in the Red Sea to explore the possible genomic adaptations of the microbes in response to environmental changes. The microbes from the brine and sediments (both surface and deep layers) of the Atlantis II Deep brine pool had similar communities whereas the effective genome size varied from 7.4 Mb in the brine to more than 9 Mb in the sediment. This genome expansion in the sediment samples was due to gene duplication as evidenced by enrichment of the homologs. The duplicated genes were highly disrupted, on average by 47.6% and 70% for the surface and deep layers of the Atlantis II Deep sediment samples, respectively. The disruptive effects appeared to be mainly due to point mutations and frameshifts. In contrast, the homologs from the Atlantis II Deep brine sample were highly conserved and they maintained relatively small copy numbers. Likely, the adaptation of the microbes in the sediments was coupled with pseudogenizations and possibly functional diversifications of the paralogs in the expanded genomes. The maintenance of the pseudogenes in the large genomes is discussed. © 2011 Wang et al.

  13. Rhodococcus jostii porin A (RjpA) functions in cholate uptake.

    Science.gov (United States)

    Somalinga, Vijayakumar; Mohn, William W

    2013-10-01

    RjpA in Rhodococcus jostii is the ortholog of a channel-forming porin, MspA. Deletion of rjpA delayed growth of R. jostii on cholate but not on cholesterol. Eventual growth on cholate involved increased expression of other porins, namely, RjpB, RjpC, and RjpD. Porins appear essential for the uptake of bile acids by mycolic acid bacteria. PMID:23892747

  14. Rhodococcus jostii Porin A (RjpA) Functions in Cholate Uptake

    OpenAIRE

    Somalinga, Vijayakumar; Mohn, William W.

    2013-01-01

    RjpA in Rhodococcus jostii is the ortholog of a channel-forming porin, MspA. Deletion of rjpA delayed growth of R. jostii on cholate but not on cholesterol. Eventual growth on cholate involved increased expression of other porins, namely, RjpB, RjpC, and RjpD. Porins appear essential for the uptake of bile acids by mycolic acid bacteria.

  15. Electrostatic properties of two porin channels from Escherichia coli.

    Science.gov (United States)

    Karshikoff, A; Spassov, V; Cowan, S W; Ladenstein, R; Schirmer, T

    1994-07-22

    The electrostatic interactions in the channels of OmpF and PhoE porins from Escherichia coli were analysed on the basis of a macroscopic multi-dielectric model of the protein-membrane complex derived from the respective porin X-ray structures. The membrane was represented as layers of distinct dielectric constants corresponding to the aliphatic core and the polar head groups of the lipids. The pKa values of the titratable groups and the electrostatic field in the region of the channel were calculated by the finite difference technique. In spite of the differences in sequences and charge constellations, the calculated electrostatic properties of the two porins are similar in several aspects: (1) unusual titration behaviour (pKa below 7) was found for some groups of the cluster of basic residues at the constriction of the pore; (2) a number of acidic groups buried between the internal loop and the barrel wall are stabilized in their protonated forms at neutral pH; (3) there is a strong transverse electrostatic field in the channel characterized by a screw-like form. The strength of the field is greatest at the region of the constriction zone. This would facilitate the diffusion of solutes with a large dipole moment such as free amino acids. Differences between the electrostatic fields of OmpF and PhoE are mainly confined to that end of the pore that faces the cell exterior in vivo. In OmpF the electrostatic potential is close to zero in this region of the channel, whereas a positive potential was found in PhoE. It was shown that the experimentally observed difference in ion selectivity of the two porins can largely be attributed to this distinct electrostatic property. PMID:8035460

  16. Importance of Porins for Biocide Efficacy against Mycobacterium smegmatis▿

    OpenAIRE

    Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

    2011-01-01

    Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the de...

  17. Porins Are Required for Uptake of Phosphates by Mycobacterium smegmatis▿

    OpenAIRE

    Wolschendorf, Frank; Mahfoud, Maysa; Niederweis, Michael

    2007-01-01

    Phosphorus is an essential nutrient, but how phosphates cross the mycobacterial cell wall is unknown. Phosphatase activity in whole cells of Mycobacterium smegmatis was significantly lower than that in lysed cells, indicating that access to the substrate was restricted. The loss of the outer membrane (OM) porin MspA also reduced the phosphatase activity in whole cells compared to that in lysed cells. A similar result was obtained for M. smegmatis that overexpressed endogenous alkaline phospha...

  18. Adaptive responses of outer membrane porin balance of Yersinia ruckeri under different incubation temperature, osmolarity, and oxygen availability.

    Science.gov (United States)

    Bystritskaya, Evgeniya; Stenkova, Anna; Chistuylin, Dmitriy; Chernysheva, Nadezhda; Khomenko, Valentina; Anastyuk, Stanislav; Novikova, Olga; Rakin, Alexander; Isaeva, Marina

    2016-08-01

    The capability of Yersinia ruckeri to survive in the aquatic systems reflects its adaptation (most importantly through the alteration of membrane permeability) to the unfavorable environments. The nonspecific porins are a key factor contributing to the permeability. Here we studied the influence of the stimuli, such as temperature, osmolarity, and oxygen availability on regulation of Y. ruckeri porins. Using qRT-PCR and SDS-PAGE methods we found that major porins are tightly controlled by temperature. Hyperosmosis did not repress OmpF production. The limitation of oxygen availability led to decreased expression of both major porins and increased transcription of the minor porin OmpY. Regulation of the porin balance in Y. ruckeri, in spite of some similarities, diverges from that system in Escherichia coli. The changes in porin regulation can be adapted in Y. ruckeri in a species-specific manner determined by its aquatic habitats. PMID:27038237

  19. Hetero-oligomeric cell wall channels (porins) of Nocardia farcinica.

    Science.gov (United States)

    Kläckta, Christian; Knörzer, Philipp; Riess, Franziska; Benz, Roland

    2011-06-01

    The cell wall of Nocardia farcinica contains a cation-selective cell wall channel, which may be responsible for the limited permeability of the cell wall of N. farcinica for negatively charged antibiotics. Based on partial sequencing of the protein responsible for channel formation derived from N. farcinica ATTC 3318 we were able to identify the corresponding genes (nfa15890 and nfa15900) within the known genome of N. farcinica IFM 10152. The corresponding genes of N. farcinica ATTC 3318 were separately expressed in the Escherichia coli BL21DE3Omp8 strain and the N-terminal His10-tagged proteins were purified to homogeneity using immobilized metal affinity chromatography. The pure proteins were designated NfpANHis and NfpBNHis, for N. farcinica porin A and N. farcinica porin B. The two proteins were checked separately for channel formation in lipid bilayers. Our results clearly indicate that the proteins NfpANHis and NfpBNHis expressed in E. coli could only together form a channel in lipid bilayer membranes. This means that the cell wall channel of N. farcinica is formed by a heterooligomer. NfpA and NfpB form together a channel that may structurally be related to MspA of Mycobacterium smegmatis based on amino acid comparison and renaturation procedure. PMID:21092733

  20. Cloning of the Koi Herpesvirus Genome as an Infectious Bacterial Artificial Chromosome Demonstrates That Disruption of the Thymidine Kinase Locus Induces Partial Attenuation in Cyprinus carpio koi▿

    Science.gov (United States)

    Costes, B.; Fournier, G.; Michel, B.; Delforge, C.; Raj, V. Stalin; Dewals, B.; Gillet, L.; Drion, P.; Body, A.; Schynts, F.; Lieffrig, F.; Vanderplasschen, A.

    2008-01-01

    Koi herpesvirus (KHV) is the causative agent of a lethal disease in koi and common carp. In the present study, we describe the cloning of the KHV genome as a stable and infectious bacterial artificial chromosome (BAC) clone that can be used to produce KHV recombinant strains. This goal was achieved by the insertion of a loxP-flanked BAC cassette into the thymidine kinase (TK) locus. This insertion led to a BAC plasmid that was stably maintained in bacteria and was able to regenerate virions when permissive cells were transfected with the plasmid. Reconstituted virions free of the BAC cassette but carrying a disrupted TK locus (the FL BAC-excised strain) were produced by the transfection of Cre recombinase-expressing cells with the BAC. Similarly, virions with a wild-type revertant TK sequence (the FL BAC revertant strain) were produced by the cotransfection of cells with the BAC and a DNA fragment encoding the wild-type TK sequence. Reconstituted recombinant viruses were compared to the wild-type parental virus in vitro and in vivo. The FL BAC revertant strain and the FL BAC-excised strain replicated comparably to the parental FL strain. The FL BAC revertant strain induced KHV infection in koi carp that was indistinguishable from that induced by the parental strain, while the FL BAC-excised strain exhibited a partially attenuated phenotype. Finally, the usefulness of the KHV BAC for recombination studies was demonstrated by the production of an ORF16-deleted strain by using prokaryotic recombination technology. The availability of the KHV BAC is an important advance that will allow the study of viral genes involved in KHV pathogenesis, as well as the production of attenuated recombinant candidate vaccines. PMID:18337580

  1. Role of Porins for Uptake of Antibiotics by Mycobacterium smegmatis▿ †

    OpenAIRE

    Danilchanka, Olga; Pavlenok, Mikhail; Niederweis, Michael

    2008-01-01

    The outer membrane of mycobacteria presents an effective permeability barrier for many antibiotics. Transport pathways across this membrane are unknown for most drugs. Here, we examined which antibiotics utilize the porin pathway across the outer membrane of the model organism Mycobacterium smegmatis. Deletion of the porins MspA and MspC drastically increased the resistance of M. smegmatis ML10 to β-lactam antibiotics, while its β-lactamase activity remained unchanged. These results are consi...

  2. Vibrio cholerae Porin OmpU Induces Caspase-independent Programmed Cell Death upon Translocation to the Host Cell Mitochondria.

    Science.gov (United States)

    Gupta, Shelly; Prasad, G V R Krishna; Mukhopadhaya, Arunika

    2015-12-25

    Porins, a major class of outer membrane proteins in Gram-negative bacteria, primarily act as transport channels. OmpU is one of the major porins of human pathogen, Vibrio cholerae. In the present study, we show that V. cholerae OmpU has the ability to induce target cell death. Although OmpU-mediated cell death shows some characteristics of apoptosis, such as flipping of phosphatidylserine in the membrane as well as cell size shrinkage and increased cell granularity, it does not show the caspase-3 activation and DNA laddering pattern typical of apoptotic cells. Increased release of lactate dehydrogenase in OmpU-treated cells indicates that the OmpU-mediated cell death also has characteristics of necrosis. Further, we show that the mechanism of OmpU-mediated cell death involves major mitochondrial changes in the target cells. We observe that OmpU treatment leads to the disruption of mitochondrial membrane potential, resulting in the release of cytochrome c and apoptosis-inducing factor (AIF). AIF translocates to the host cell nucleus, implying that it has a crucial role in OmpU-mediated cell death. Finally, we observe that OmpU translocates to the target cell mitochondria, where it directly initiates mitochondrial changes leading to mitochondrial membrane permeability transition and AIF release. Partial blocking of AIF release by cyclosporine A in OmpU-treated cells further suggests that OmpU may be inducing the opening of the mitochondrial permeability transition pore. All of these results lead us to the conclusion that OmpU induces cell death in target cells in a programmed manner in which mitochondria play a central role.

  3. Vibrio cholerae porin OmpU induces LPS tolerance by attenuating TLR-mediated signaling.

    Science.gov (United States)

    Sakharwade, Sanica C; Mukhopadhaya, Arunika

    2015-12-01

    Porins can act as pathogen-associated molecular patterns, can be recognized by the host immune system and modulate immune responses. Vibrio choleraeporin OmpU aids in bacterial survival in the human gut by increasing resistance against bile acids and anti-microbial peptides. V. choleraeOmpU is pro-inflammatory in nature. However, interestingly, it can also down-regulate LPS-mediated pro-inflammatory responses. In this study, we have explored how OmpU-pretreatment affects LPS-mediated responses. Our study indicates that OmpU-pretreatment followed by LPS-activation does not induce M2-polarization of macrophages/monocytes. Further, OmpU attenuates LPS-mediated TLR2/TLR6 signaling by decreasing the association of TLRs along with recruitment of MyD88 and IRAKs to the receptor complex. This results in decreased translocation of NFκB in the nucleus. Additionally, OmpU-pretreatment up-regulates expression of IRAK-M, a negative regulator of TLR signaling, in RAW 264.7 mouse macrophage cells upon LPS-stimulation. Suppressor cytokine IL-10 is partially involved in OmpU-induced down-regulation of LPS-mediated TNFα production in human PBMCs. Furthermore, OmpU-pretreatment also affects macrophage function, by enhancing phagocytosis in LPS-treated RAW 264.7 cells, and down-regulates LPS-induced cell surface expression of co-stimulatory molecules. Altogether, OmpU causes suppression of LPS-mediated responses by attenuating the LPS-mediated TLR signaling pathway.

  4. Evaluation of Porin Interaction with Adenine Nucleotide Translocase and Cyclophilin-D Proteins after Brain Ischemia and Reperfusion

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Atlasi

    2011-01-01

    Full Text Available Objective (s Porin is a mitochondrial outer membrane channel, which usually functions as the pathway for the movement of various substances in and out of the mitochondria and is considered to be a component of the permeability transition (PT pore complex that plays a role in the PT. We addressed the hypothesis that porin interacts with other mitochondrial proteins after ischemic injury.Materials and MethodsFor this purpose, we used in vivo 4-vessel occlusion model of rat brain and porin purification method by hydroxyapatite column. After SDS gel electrophoresis and silver nitrate staining, Western blotting was done for porin, adenine nucleotide translocase and cyclophilin-D proteins.Results Porin was purified from mitochondrial mixture in ischemic brain and control groups. Investigation of interaction of adenine nucleotide transposes (ANT and cyclophilin-D with porin by Western blotting showed no proteins co-purified with porin from injured tissues.Conclusion The present study implies that there may not be interaction between porin, and ANT or cyclophilin-D, and if there is any, it is not maintained during the purification procedure.

  5. Imipenem- and meropenem-resistant mutants of Enterobacter cloacae and Proteus rettgeri lack porins.

    Science.gov (United States)

    Raimondi, A; Traverso, A; Nikaido, H

    1991-01-01

    Carbapenems such as imipenem and meropenem are not rapidly hydrolyzed by commonly occurring beta-lactamases. Nevertheless, it was possible, by mutagenesis and selection, to isolate mutant strains of Enterobacter cloacae and Proteus rettgeri that are highly resistant to meropenem and imipenem. Two alterations were noted in the E. cloacae mutants. First, the mutant strains appeared to be strongly derepressed in the production of beta-lactamases, which reached a very high level when the strains were grown in the presence of imipenem. Second, these mutants were deficient in the production of nonspecific porins, as judged by the pattern of outer membrane proteins as well as by reconstitution assays of permeability. As with most porin-deficient mutants, their cultures were unstable, and their cultivation in the absence of carbapenems rapidly led to an overgrowth of porin-producing revertants. Analysis of the data suggests that the synergism between the lowered outer membrane permeability and the slow but significant hydrolysis of carbapenems by the overproduced enzymes can explain the resistance phenotypes quantitatively, although the possibility of alteration of the target cannot be excluded at present. With P. rettgeri mutants, there was no indication of further derepression of beta-lactamase, but the enzyme hydrolyzed imipenem much more efficiently than the E. cloacae enzyme did. In addition, the major porin was absent in one mutant strain. These results suggest that a major factor for the carbapenem resistance of these enteric bacteria is the porin deficiency, and this conclusion forms a contrast to the situation in Pseudomonas aeruginosa, in which the most prevalent class of imipenem-resistant mutants appears to lack the specific channel protein D2 yet retains the major nonspecific porin F. Images PMID:1656855

  6. Characterisation of porin genes from Mycobacterium fortuitum and their impact on growth

    Directory of Open Access Journals (Sweden)

    Tykiel Verena

    2009-02-01

    Full Text Available Abstract Background Highly pathogenic mycobacteria like Mycobacterium tuberculosis are characterised by their slow growth and their ability to reside and multiply in the very hostile phagosomal environment and a correlation between the growth rate of mycobacteria and their pathogenicity has been hypothesised. Here, porin genes from M. fortuitum were cloned and characterised to address their impact on the growth rate of fast-growing and pathogenic mycobacteria. Results Two genes encoding porins orthologous to MspA from M. smegmatis, porM1 and porM2, were cloned from M. fortuitum strains, which were originally isolated from human patients. Both porin genes were at least partially able to complement the mutations of a M. smegmatis mutant strain lacking the genes mspA and mspC with respect to the growth rate. PorM1 and porM2 were present in different strains of M. fortuitum including the type strain. Comparative expression analysis of porM genes revealed divergent porin expression among analysed M. fortuitum strains. Repression of the expression of porins by antisense technique decreased the growth rates of different M. fortuitum. The effects of over-expression of porM1 as well as porM2 varied depending on the strain and the concentration of antibiotic added to the medium and indicated that PorM1 and PorM2 enhance the growth of M. fortuitum strains, but also the diffusion of the antibiotic kanamycin into the cells. Conclusion This study demonstrates the important role of porin expression in growth as well as antibiotic susceptibility of the opportunistic bacterium M. fortuitum.

  7. Direct Observation of Gold Nanoparticle Assemblies with the Porin MspA on Mica

    OpenAIRE

    Basel, Matthew T.; Dani, Raj Kumar; Kang, Myungshim; Pavlenok, Mikhail; Chikan, Viktor; Smith, Paul E.; Niederweis, Michael; Stefan H. Bossmann

    2009-01-01

    The octameric porin MspA from Mycobacterium smegmatis is sufficiently stable to form a non-membrane-supported stand-alone porin on Mica surfaces. About 98% of all MspA octamers were found to stand upright on Mica, with their periplasmic loop regions bound to the hydrophilic Mica surface. Both, small (d = 3.7 nm) and large (d = 17 nm) gold nanoparticles bind to MspA, however in different positions: small gold nanoparticles bind within the MspA pore, whereas the large gold nanoparticles bind to...

  8. Helicobacter pylori HopE and HopV porins present scarce expression among clinical isolates

    Institute of Scientific and Technical Information of China (English)

    Maritza; Lienlaf; Juan; Pablo; Morales; María; Inés; Díaz; Rodrigo; Díaz; Elsa; Bruce; Freddy; Siegel; Gloria; León; Paul; R; Harris; Alejandro; Venegas

    2010-01-01

    AIM:To evaluate how widely Helicobacter pylori (H. pylori ) HopE and HopV porins are expressed among Chilean isolates and how seroprevalent they are among infected patients in Chile.METHODS: H. pylori hopE and hopV genes derived from strain CHCTX-1 were cloned by polymerase chain reaction (PCR), sequenced and expressed in Escherichia coli AD494 (DE3). Gel-purified porins were used to prepare polyclonal antibodies. The presence of both genes was tested by PCR in a collection of H. pylori clinical isolates an...

  9. Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

    Science.gov (United States)

    Sanyasi, Sridhar; Majhi, Rakesh Kumar; Kumar, Satish; Mishra, Mitali; Ghosh, Arnab; Suar, Mrutyunjay; Satyam, Parlapalli Venkata; Mohapatra, Harapriya; Goswami, Chandan; Goswami, Luna

    2016-04-01

    Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20–40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.

  10. Anti-hemolytic, hemagglutination inhibition and bacterial membrane disruptive properties of selected herbal extracts attenuate virulence of Carbapenem Resistant Escherichia coli.

    Science.gov (United States)

    Thakur, Pallavi; Chawla, Raman; Narula, Alka; Goel, Rajeev; Arora, Rajesh; Sharma, Rakesh Kumar

    2016-06-01

    Expression of a multitude of virulence factors by multi-drug resistant microbial strains, e.g., Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria), is responsible for resistance against beta-lactam antibiotics. Hemolysin production and induction of hemagglutination by bacterial surface receptors inflicts direct cytotoxicity by destroying host phagocytic and epithelial cells. We have previously reported that Berberis aristata, Camellia sinensis, Cyperus rotundus Holarrhena antidysenterica and Andrographis paniculata are promising herbal leads for targeting Carbapenem resistant Escherichia coli. These herbal leads were analyzed for their anti-hemolytic potential by employing spectrophotometric assay of hemoglobin liberation. Anti-hemagglutination potential of the extracts was assessed by employing qualitative assay of visible RBC aggregate formation. Camellia sinensis (PTRC-31911-A) exhibited anti-hemolytic potential of 73.97 ± 0.03%, followed by Holarrhena antidysenterica (PTRC-8111-A) i.e., 68.32 ± 0.05%, Berberis aristata (PTRC-2111-A) i.e., 60.26 ± 0.05% and Cyperus rotundus (PTRC-31811-A) i.e., 53.76 ± 0.03%. Comprehensive, visual analysis of hemagglutination inhibition revealed that only Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) exhibited anti-hemagglutination activity. However, Andrographis paniculata (PTRC-11611-A) exhibited none of the inhibitory activities. Furthermore, the pair wise correlation analysis of the tested activities with quantitative phytochemical descriptors revealed that an increased content of alkaloid; flavonoids; polyphenols, and decreased content of saponins supported both the activities. Additionally, flow cytometry revealed that cell membrane structures of CRE were damaged by extracts of Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) at their respective Minimum Inhibitory Concentrations, thereby confirming noteworthy antibacterial

  11. Family Disruptions

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care ... Life Listen Español Text Size Email Print Share Family Disruptions Page Content Article Body No matter how ...

  12. Sustainable Disruptions

    DEFF Research Database (Denmark)

    Friis, Silje Alberthe Kamille; Kjær, Lykke Bloch

    2016-01-01

    Since 2012 the Sustainable Disruptions (SD) project at the Laboratory for Sustainability at Design School Kolding (DK) has developed and tested a set of design thinking tools, specifically targeting the barriers to economically, socially, and environmentally sustainable business development...

  13. Disrupted Disclosure

    DEFF Research Database (Denmark)

    Krause Hansen, Hans; Uldam, Julie

    appearances become challenged through disruptive disclosures in mediaenvironments characterized by multiple levels of visibility, with companies both observing andbeing observed by civil society groups that criticize them; (c) why and how the mobilization aroundtransparency and ensuing practices...

  14. Marine organisms as source of extracts to disrupt bacterial communication: bioguided isolation and identification of quorum sensing inhibitors from Ircinia felix

    Directory of Open Access Journals (Sweden)

    Jairo Quintana

    2015-06-01

    Full Text Available AbstractIn this study, 39 extracts from marine organisms were evaluated as quorum sensing inhibitors, collected in the Colombian Caribbean Sea and the Brazilian Coast including 26 sponges, seven soft corals, five algae and one zooanthid. The results showed that crude extracts from the soft coral Eunicea laciniata, and the sponges Svenzea tubulosa, Ircinia felix and Neopetrosia carbonaria were the most promising source of quorum sensing inhibitors compounds without affecting bacterial growth, unlike the raw extracts of Agelas citrina, Agelas tubulata, Iotrochota arenosa, Topsentia ophiraphidites, Niphates caycedoi, Cliona tenuis, Ptilocaulis walpersi, Petrosia pellasarca, and the algae Laurencia catarinensis and Laurencia obtusa, which displayed potent antibacterial activity against the biosensors employed. The crude extract from the sponge I. felix was fractionated, obtaining furanosesterterpenes which were identified and evaluated as quorum sensing inhibitors, showing a moderate activity without affecting the biosensor's growth.

  15. A morphological study of the changes in the ultrastructure of a bacterial biofilm disrupted by an ac corona discharge in air

    Science.gov (United States)

    Stepanova, Olga; Rybalchenko, Oksana; Astafiev, Alexander; Orlova, Olga; Kudryavtsev, Anatoly; Kapustina, Valentina

    2016-08-01

    The morphology of bacterial cells and biofilms subjected to a low frequency (˜105 Hz) ac (˜10-1 A) corona discharge was investigated using electron microscopy. A low-frequency ac corona discharge in air is shown to have a bactericidal and bacteriostatic effect on Escherichia coli M17 culture at both the cellular and population levels. Corona exposure inhibits the formation of a microbial community and results in the destruction of formed biofilms. This paper presents data on changes in the ultrastructure of cells and biofilms after corona treatment. Our results suggest that the E. coli M17 cells inside biofilms are affected with results similar to sub-lethal and lethal thermal exposure. Some of the biological aspects of colony and biofilm cells death are evaluated. Morphological changes in the ultrastructure of the biofilms under corona treatment are described. Our results indicate that the heating effect is the main factor responsible for the corona-induced inactivation of bacteria.

  16. Luontoretkien kävijätutkimus : Kohteena Porin kaupungin ympäristötoimisto

    OpenAIRE

    Ojaniemi, Helena

    2009-01-01

    Porin kaupungin ympäristötoimisto yhteistyökumppaneineen järjestää vuosittain 10 – 12 luontoretkeä. Tässä opinnäytetyössä tutkittiin näiden luontoretkien osallistujien profiilia ja heidän mielipiteitään retkien sisällöstä, lukumäärästä ja mahdollisista kehitystarpeista. Tutkimuksen toteuttamiseen käytettiin kvantitatiivista tutkimusta. Opinnäytetyön teoriaosuudessa käsiteltiin Porin kaupungin ympäristötoimistoa ja käytiin läpi sen vuonna 2008 järjestämät luontoretket ja tapahtumat. Lisäksi pe...

  17. Direct observation of gold nanoparticle assemblies with the porin MspA on mica.

    Science.gov (United States)

    Basel, Matthew T; Dani, Raj Kumar; Kang, Myungshim; Pavlenok, Mikhail; Chikan, Viktor; Smith, Paul E; Niederweis, Michael; Bossmann, Stefan H

    2009-02-24

    The octameric porin MspA from Mycobacterium smegmatis is sufficiently stable to form a nonmembrane-supported stand-alone porin on mica surfaces. About 98% of all MspA octamers were found to stand upright on mica, with their periplasmic loop regions bound to the hydrophilic mica surface. Both, small (d = 3.7 nm) and large (d = 17 nm) gold nanoparticles bind to MspA, however, in different positions: small gold nanoparticles bind within the MspA pore, whereas the large gold nanoparticles bind to the upper region of MspA. These experiments demonstrate that gold nanoparticles can be positioned at different, well-defined distances from the underlying surface using the MspA pore as a template. These findings represent a significant step toward the use of electrically insulating stable proteins in combination with metal nanoparticles in nanodevices. PMID:19236086

  18. Expression and regulation of the porin gene mspA of Mycobacterium smegmatis

    OpenAIRE

    Hillmann, Dietmar

    2007-01-01

    Mycobacteria possess a unique, lipid-rich cell envelope which strongly contributes to their intrinsic resistance against many antibiotics. Hydrophilic compounds cross this permeability barrier by diffusion through transmembrane channel proteins, the so called porins. The balance of nutrient acquisition and blockade of toxic molecules is crucial for adaptation to changing environmental conditions and in gram-negative bacteria it is achieved by a complex network of regulatory circuits. However,...

  19. Functions of the periplasmic loop of the porin MspA from Mycobacterium smegmatis.

    Science.gov (United States)

    Huff, Jason; Pavlenok, Mikhail; Sukumaran, Suja; Niederweis, Michael

    2009-04-10

    MspA is the major porin of Mycobacterium smegmatis and mediates diffusion of small and hydrophilic solutes across the outer membrane. The octameric structure of MspA, its sharply defined constriction zone, and a large periplasmic loop L6 represent novel structural features. L6 consists of 13 amino acids and is directly adjacent to the constriction zone. Deletion of 3, 5, 7, 9, and 11 amino acids of the L6 loop resulted in functional pores that restored glucose uptake and growth of a porin mutant of M. smegmatis. Lipid bilayer experiments revealed that all mutant channels were noisier than wild type (wt) MspA, indicating that L6 is required for pore stability in vitro. Voltage gating of the Escherichia coli porin OmpF was attributed to loops that collapse into the channel in response to a strong electrical field. Here, we show that deletion mutants Delta7, Delta9, and Delta11 had critical voltages similar to wt MspA. This demonstrated that the L6 loop is not the primary voltage-dependent gating mechanism of MspA. Surprisingly, large deletions in L6 resulted in 3-6-fold less extractable pores, whereas small deletions did not alter expression levels of MspA. Pores with large deletions in L6 were more permissive for glucose than smaller deletion mutants, whereas their single channel conductance was similar to that of wt MspA. These results indicate that translocation of ions through the MspA pore is governed by different mechanisms than that of neutral solutes. This is the first study identifying a molecular determinant of solute translocation in a mycobacterial porin. PMID:19208627

  20. Nanoscopic surfactant behavior of the porin MspA in aqueous media

    OpenAIRE

    Perera, Ayomi S; Hongwang Wang; Tej B. Shrestha; Deryl L Troyer; Stefan H. Bossmann

    2013-01-01

    The mycobacterial porin MspA is one of the most stable channel proteins known to date. MspA forms vesicles at low concentrations in aqueous buffers. Evidence from dynamic light scattering, transmission electron microscopy and zeta-potential measurements by electrophoretic light scattering indicate that MspA behaves like a nanoscale surfactant. The extreme thermostability of MspA allows these investigations to be carried out at temperatures as high as 343 K, at which most other proteins would ...

  1. Disrupting Business

    DEFF Research Database (Denmark)

    Cox, Geoff; Bazzichelli, Tatiana

    Disruptive Business explores some of the interconnections between art, activism and the business concept of disruptive innovation. With a backdrop of the crisis of financial capitalism, austerity cuts in the cultural sphere, the idea is to focus on potential art strategies in relation to a broken...... economy. In a perverse way, we ask whether this presents new opportunities for cultural producers to achieve more autonomy over their production process. If it is indeed possible, or desirable, what alternative business models emerge? The book is concerned broadly with business as material for reinvention...

  2. Ultrafast proton transport in sub-1-nm diameter carbon nanotube porins

    Science.gov (United States)

    Tunuguntla, Ramya H.; Allen, Frances I.; Kim, Kyunghoon; Belliveau, Allison; Noy, Aleksandr

    2016-07-01

    Proton transport plays an important role in many biological processes due to the ability of protons to rapidly translocate along chains of hydrogen-bonded water molecules. Molecular dynamics simulations have predicted that confinement in hydrophobic nanochannels should enhance the rate of proton transport. Here, we show that 0.8-nm-diameter carbon nanotube porins, which promote the formation of one-dimensional water wires, can support proton transport rates exceeding those of bulk water by an order of magnitude. The transport rates in these narrow nanotube pores also exceed those of biological channels and Nafion. With larger 1.5-nm-diameter nanotube porins, proton transport rates comparable to bulk water are observed. We also show that the proton conductance of these channels can be modulated by the presence of Ca2+ ions. Our results illustrate the potential of small-diameter carbon nanotube porins as a proton conductor material and suggest that strong spatial confinement is a key factor in enabling efficient proton transport.

  3. MspA Porin-Gold Nanoparticle Assemblies: Enhanced Binding through a Controlled Cysteine Mutation.

    Science.gov (United States)

    Dani, Raj Kumar; Kang, Myungshim; Kalita, Mausam; Smith, Paul E; Bossmann, Stefan H; Chikan, Viktor

    2008-04-01

    In this study, the interactions of two gold nanoparticles of different sizes (average diameters of 3.7 +/- 2.6 and 17 +/- 3 nm) with octameric mycobacterial porin A from Mycobacterium smegmatis (MspA) and a mutant of MspA featuring a cysteine mutation in position 126 (Q126C) are investigated. From the observation of enhanced photoluminescence quenching, it is inferred that the presence of eight cysteines in the MspA Q126C mutant significantly enhances the binding of selected small gold nanoparticles within the inner pore of MspA. The large gold nanoparticle/porin complex shows photoluminescence enhancement, which is expected since the larger nanoparticles cannot dock within the homopore of MspA due to size exclusion. In addition to the fluorescence experiments, observation of energy transfer from the small gold nanoparticles to the MspA shows the close proximity of the small gold nanoparticles with the porin. Interestingly, the energy transfer of the large nanoparticle/MspA complex is completely missing. From high-performance liquid chromatography data, the estimated binding constants for small Au@MspA, large Au@MspA, small Au@MspAcys, and large Au@MspAcys are 1.3 x 10 (9), 2.22 x 10 (10), > 10 (12) (irreversible), and 1.7 x 10 (10), respectively. PMID:18318505

  4. Use of nonelectrolytes reveals the channel size and oligomeric constitution of the Borrelia burgdorferi P66 porin.

    Directory of Open Access Journals (Sweden)

    Iván Bárcena-Uribarri

    Full Text Available In the Lyme disease spirochete Borrelia burgdorferi, the outer membrane protein P66 is capable of pore formation with an atypical high single-channel conductance of 11 nS in 1 M KCl, which suggested that it could have a larger diameter than 'normal' Gram-negative bacterial porins. We studied the diameter of the P66 channel by analyzing its single-channel conductance in black lipid bilayers in the presence of different nonelectrolytes with known hydrodynamic radii. We calculated the filling of the channel with these nonelectrolytes and the results suggested that nonelectrolytes (NEs with hydrodynamic radii of 0.34 nm or smaller pass through the pore, whereas neutral molecules with greater radii only partially filled the channel or were not able to enter it at all. The diameter of the entrance of the P66 channel was determined to be ≤1.9 nm and the channel has a central constriction of about 0.8 nm. The size of the channel appeared to be symmetrical as judged from one-sidedness of addition of NEs. Furthermore, the P66-induced membrane conductance could be blocked by 80-90% by the addition of the nonelectrolytes PEG 400, PEG 600 and maltohexaose to the aqueous phase in the low millimolar range. The analysis of the power density spectra of ion current through P66 after blockage with these NEs revealed no chemical reaction responsible for channel block. Interestingly, the blockage of the single-channel conductance of P66 by these NEs occurred in about eight subconductance states, indicating that the P66 channel could be an oligomer of about eight individual channels. The organization of P66 as a possible octamer was confirmed by Blue Native PAGE and immunoblot analysis, which both demonstrated that P66 forms a complex with a mass of approximately 460 kDa. Two dimension SDS PAGE revealed that P66 is the only polypeptide in the complex.

  5. Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ananthan S

    2005-01-01

    Full Text Available PURPOSE: Porins are outer membrane protein (OMP that form water filled channels that permit the diffusion of small hydrophilic solutes like -lactam antibiotics across the outer membrane. Two major porins that facilitate diffusion of antimicrobials have been described in Klebsiella spp. and Escherichia coli. The present study was carried out to examine the role of porins among Extended Spectrum -Lactamase (ESBL and AmpC -Lactamase positive strains of Klebsiella spp. and E.coli. METHODS: Preparation of OMP from phenotypically characterized clinical isolates K.pneumoniae and E.coli and the separation of the proteins by sodium dodecyl sulfate - polyacrylamide gel electrophoresis were performed as per a previously described procedure. RESULTS: OMP analysis revealed that cefoxitin and ceftazidime resistance was mediated by loss of a porin Omp K35 in the isolates of K.pneumoniae and E.coli. CONCLUSIONS: Loss of porin mediated resistance mechanism against cefoxitin was observed among the multidrug resistant K.pneumoniae and E.coli.

  6. Construction of Prokaryotic Expression Plasmid of Fusion Protein Including Porin A and Porin B of Neisseria Gonorrhoeae and Its Expression in E.coli

    Institute of Scientific and Technical Information of China (English)

    廖芳; 宋启发; 万沐芬

    2004-01-01

    In order to provide a rational research basis for clinical detection and genetic engineering vaccine, plasmid pET-28a (+) encoding both Porin gene PIA and PIB of Neisseria gonorrhoeae was constructed and a fusion protein in E. coli DE3 expressed. The fragments of PIA and PIB gene of Neisseria gonorrhoeae were amplified and cloned into prokaryotic expression plasmid pET-28a (+) with double restriction endonuclease cut to construct recombinant pET-PIB-PIA. The recombinant was verified with restriction endonuclease and sequenced and transformed into E. coli DE3 to express the fusion protein PIB-PIA after induced with IPTG. The results showed PIA-PIB fusion DNA fragment was proved correct through sequencing. A 67 kD (1 kD=0. 992 1 ku) fusion protein had been detected by SDS-PAGE. It was concluded that the fusion protein was successively expressed.

  7. Designed to penetrate: Time-resolved interaction of single antibiotic molecules with bacterial pores

    Science.gov (United States)

    Nestorovich, Ekaterina M.; Danelon, Christophe; Winterhalter, Mathias; Bezrukov, Sergey M.

    2002-07-01

    Membrane permeability barriers are among the factors contributing to the intrinsic resistance of bacteria to antibiotics. We have been able to resolve single ampicillin molecules moving through a channel of the general bacterial porin, OmpF (outer membrane protein F), believed to be the principal pathway for the -lactam antibiotics. With ion channel reconstitution and high-resolution conductance recording, we find that ampicillin and several other efficient penicillins and cephalosporins strongly interact with the residues of the constriction zone of the OmpF channel. Therefore, we hypothesize that, in analogy to substrate-specific channels that evolved to bind certain metabolite molecules, antibiotics have "evolved" to be channel-specific. Molecular modeling suggests that the charge distribution of the ampicillin molecule complements the charge distribution at the narrowest part of the bacterial porin. Interaction of these charges creates a region of attraction inside the channel that facilitates drug translocation through the constriction zone and results in higher permeability rates.

  8. SATAKUNNAN AMMATTIKORKEAKOULUN PORIN LIIKETALOUDEN TOIMIPISTEEN ENSIMMÄISEN VUODEN OPISKELIJOIDEN NUKKUMISTAVAT JA NIITÄ EDISTÄVÄT TEKIJÄT

    OpenAIRE

    Kauko, Verna

    2011-01-01

    Tämän opinnäytetyön tarkoitus oli selvittää Satakunnan ammattikorkeakoulun Porin liiketalouden toimipisteen ensimmäisen vuoden opiskelijoiden nukkumistapoja ja niitä edistäviä tekijöitä. Tavoitteena oli saada tietoa Satakunnan ammattikorkeakoulun Porin toimipisteen ensimmäisen vuoden liiketalouden opiskelijoiden nukkumisesta ja unenlaatuun vaikuttavista tekijöistä. Satakunnan ammattikorkeakoulun liiketalouden toimipisteen terveydenhoitaja voi hyödyntää opinnäytetyön tuloksista saatua tietoa u...

  9. Seudullinen yhteistyö hyvinvointipalveluissa : Porin seudun vanhustenhuollon laatujärjestelmä

    OpenAIRE

    Lehtoranta, Heini

    2007-01-01

    Porin seudulla rakennettiin laatujärjestelmää (ISO 9001:2000) vanhustenhuoltoon vuosina 2004-2006. Laatujärjestelmän avulla tavoiteltiin palvelujen laadun, saatavuuden ja asiakaslähtöisyyden lisäämistä seudun palvelustrategian tavoitteiden mukaisesti. Tämän opinnäytetyön tavoitteena oli kuvata laatujärjestelmän rakentamisprosessin tausta, vaiheet ja tulokset vuoden 2006 loppuun mennessä. Opinnäytetyön aineistona käytettiin projekteissa laadittuja materiaaleja, kokouspöytäkirjoja, seudun kehit...

  10. Functions of the Periplasmic Loop of the Porin MspA from Mycobacterium smegmatis*

    OpenAIRE

    Huff, Jason; Pavlenok, Mikhail; Sukumaran, Suja; Niederweis, Michael

    2009-01-01

    MspA is the major porin of Mycobacterium smegmatis and mediates diffusion of small and hydrophilic solutes across the outer membrane. The octameric structure of MspA, its sharply defined constriction zone, and a large periplasmic loop L6 represent novel structural features. L6 consists of 13 amino acids and is directly adjacent to the constriction zone. Deletion of 3, 5, 7, 9, and 11 amino acids of the L6 loop resulted in functional pores that restored glucose uptake a...

  11. Expression of the Major Porin Gene mspA Is Regulated in Mycobacterium smegmatis▿ †

    OpenAIRE

    Hillmann, Dietmar; Eschenbacher, Iris; Thiel, Anja; Niederweis, Michael

    2006-01-01

    MspA is the major porin of Mycobacterium smegmatis and is important for diffusion of small and hydrophilic solutes across its unique outer membrane. The start point of transcription of the mspA gene was mapped by primer extension and S1 nuclease experiments. The main promoter driving transcription of mspA was identified by single point mutations in lacZ fusions and resembled σA promoters of M. smegmatis. However, a 500-bp upstream fragment including PmspA in a transcriptional fusion with lacZ...

  12. Yhteistyöpohjaiset matkailun hyvinvointipalvelut osana Porin Sokos Hotel Vaakunan toimintaa

    OpenAIRE

    Kuusinen, Jenni

    2007-01-01

    Tässä opinnäytetyössä tutkittiin Sokos Hotel Porin Vaakunan ja sen tiloissa toimintansa joulukuussa 2006 aloittaneen Vitamin.fi - Lifestyle Spa -hoitolan yhteistyön toimivuutta sekä kyseisen hoitolan asiakkaiden tyytyväisyyttä hoitolan palveluun ja toimintaan kokonaisuutena. Tutkimus tehtiin hoitolan asiakkaiden näkökulmasta. Lisäksi työssä tehtiin sisäiseen markkinointiin kuuluva ohjeistusvihko molempien yritysten henkilökunnan käyttöön. Vihkon on tarkoitus olla apuna uusien yhteistyön mukan...

  13. Structural and dynamical properties of the porins OmpF and OmpC: insights from molecular simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Hajjar, Eric; Ruggerone, Paolo; Ceccarelli, Matteo, E-mail: matteo.ceccarelli@dsf.unica.i [Istituto Officina dei Materiali/CNR UOS SLACS, c/o Department of Physics, University of Cagliari, SP Monserrato-Sestu Km 0.700, Monserrato I-09042 (Italy)

    2010-11-17

    In this paper we investigate the structural and dynamical properties of the two major porins (OmpF and OmpC) in Escherichia coli, using molecular dynamics (MD) simulations. In particular we characterized the atomic fluctuations, correlated motions, temperature dependence, solvent-accessible cross-sectional area and water dynamics in the key regions of the two channels. Our in-depth analysis allows us to highlight the importance of both the key conserved and substituted residues between OmpF and OmpC. The latter is characterized by a narrower and longer constriction region with respect to OmpF. OmpC also showed a higher stability upon increasing temperature. We then present the results of transport properties by using accelerated MD simulations to probe the diffusion of norfloxacin (a fluoroquinolone antibiotic) through the two porins OmpF/OmpC. Our study constitutes a step forward towards understanding the structure-function relationship of the two porins' channels. This will benefit the research of antibacterials with improved permeation properties and nanopores that aim to use these porins as sensing systems.

  14. Maahanmuuttajuuden haasteet Porin kaupungin kunnallisessa päivähoidossa : päiväkotien henkilöstön kokemuksia

    OpenAIRE

    Santala , Emma; Tranberg, Jenni

    2010-01-01

    Opinnäytetyön aiheena oli tutkia Porin kaupungin päivähoidon henkilöstön kokemuksia maahanmuuttajaperheistä päiväkodin asiakkaina. Tavoitteena oli tarkastella päiväkodin henkilökunnan kokemuksiin maahanmuuttajalasten ja heidän perheidensä tuomiin haasteisiin Porin kaupungin päivähoidossa sekä siihen kuinka näitä haasteita on eri päiväkodeissa ratkaistu. Opinnäytetyössä selvitettiin, kuinka Porin kunnallinen päivähoito kohtaa Suomeen muuttaneet maahanmuuttajaperheet. Yhteiskunnassamme maah...

  15. Structure of a putative BenF-like porin from Pseudomonas fluorescens Pf-5 at 2.6 A resolution

    Energy Technology Data Exchange (ETDEWEB)

    Sampathkumar, P.; Swaminathan, S.; Lu, F.; Zhao, X.; Li, Z.; Gilmore, J.; Bain, K.; Rutter, M. E.; Gheyi, T.; Schwinn, D.; Bonanno, J. B.; Pieper, U.; Fajardo, J. E.; Fiser, A.; Almo, S. C.; Chance, M. R.; Baker, D.; Atwell, S.; Thompson, D. A.; Emtage, J. S.; Wasserman, S. R.; Sali, A.; Sauder, J. M.; Burley, S. K.

    2010-11-01

    Gram-negative bacteria typically overcome poor permeability of outer membranes through general porins like OmpF and OmpC, which form water-filled transmembrane pores permitting diffusion of hydrophilic molecules with no particular selectivity. Many bacteria lacking such general porins use substrate-specific porins to overcome growth-limiting conditions and facilitate selective transport of metabolites. Exclusive reliance on substrate-specific porins yields lower membrane permeability to small molecules (<600 Da) versus that seen for Escherichia coli. In Pseudomonads, transit of most small molecules across the cell membrane is thought to be mediated by substrate-specific channels of the OprD superfamily. This property explains, at least in part, the high incidence of Pseudomonas aeruginosa antibiotic resistance. High-throughput DNA sequencing of the P. aeruginosa chromosome revealed the presence of 19 genes encoding structurally related, substrate-specific porins (with 30-45% pairwise amino acid sequence identity) that mediate transmembrane passage of small, water-soluble compounds. The OprD superfamily encompasses the eponymous OprD subfamily, which includes 9 P. aeruginosa proteins that convey basic amino acids and carbapenem antibiotics, and the OpdK subfamily, which includes 11 P. aeruginosa proteins that convey aromatic acids and other small aromatic compounds. Genome sequencing of other gram-negative bacteria has revealed additional members of the OprD and OpdK subfamilies in various organisms, including other pseudomonads. Among the many bacteria in which OprD superfamily members have been identified are P. putida, P. fluorescens Pf-5, P. syringae, and Azotobacter vinelandii, all of which share closely related genes that encode the so-called BenF-like porins. In P. putida, benF is part of an operon involved in benzoate catabolism regulated by benR. Within this operon, benK, benE, and benF genes have been suggested to contribute toward either influx or efflux

  16. Nanoscopic surfactant behavior of the porin MspA in aqueous media

    Directory of Open Access Journals (Sweden)

    Ayomi S. Perera

    2013-04-01

    Full Text Available The mycobacterial porin MspA is one of the most stable channel proteins known to date. MspA forms vesicles at low concentrations in aqueous buffers. Evidence from dynamic light scattering, transmission electron microscopy and zeta-potential measurements by electrophoretic light scattering indicate that MspA behaves like a nanoscale surfactant. The extreme thermostability of MspA allows these investigations to be carried out at temperatures as high as 343 K, at which most other proteins would quickly denature. The principles of vesicle formation of MspA as a function of temperature and the underlying thermodynamic factors are discussed here. The results obtained provide crucial evidence in support of the hypothesis that, during vesicle formation, nanoscopic surfactant molecules, such as MspA, deviate from the principles underlined in classical surface chemistry.

  17. Nanoscopic surfactant behavior of the porin MspA in aqueous media.

    Science.gov (United States)

    Perera, Ayomi S; Wang, Hongwang; Shrestha, Tej B; Troyer, Deryl L; Bossmann, Stefan H

    2013-01-01

    The mycobacterial porin MspA is one of the most stable channel proteins known to date. MspA forms vesicles at low concentrations in aqueous buffers. Evidence from dynamic light scattering, transmission electron microscopy and zeta-potential measurements by electrophoretic light scattering indicate that MspA behaves like a nanoscale surfactant. The extreme thermostability of MspA allows these investigations to be carried out at temperatures as high as 343 K, at which most other proteins would quickly denature. The principles of vesicle formation of MspA as a function of temperature and the underlying thermodynamic factors are discussed here. The results obtained provide crucial evidence in support of the hypothesis that, during vesicle formation, nanoscopic surfactant molecules, such as MspA, deviate from the principles underlined in classical surface chemistry. PMID:23766950

  18. Detection of β-Lactamases and Outer Membrane Porins among Klebsiella pneumoniae Strains Isolated in Iran

    Directory of Open Access Journals (Sweden)

    Ali Hashemi

    2014-01-01

    Full Text Available This descriptive study was accomplished on 83 K. pneumoniae strains isolated from two hospitals in Tehran, Iran. Antibiotic susceptibility tests were performed by disc diffusion and broth microdilution methods. ESBLs, MBL, Amp-C, and KPC producing strains were detected by phenotypic confirmatory test, combination disk diffusion test (CDDT, Amp-C detection kit, and modified Hodge test, respectively. OXA-48, NDM-1, and CTX-M-15 genes were detected by PCR and sequencing methods. The outer membrane porins such as OmpK35 and OmpK36 were analysed by SDS-PAGE, PCR, and sequencing methods. From 83 K. pneumoniae isolates, 48 (57.5%, 3 (3.5%, 23 (28%, and 5 (6% were ESBL, MBL, Amp-C, and KPC positive, respectively. The CTX-M-15 gene was detected in 30 (62.5% and OXA-48 gene was found in 2 (4.1% of the 48 ESBL-producing isolates. Two isolates harboured both OXA-48 and CTX-M-15; NDM-1 gene was not detected in this study. Outer membrane porin, OmpK35, was detected in 30 (62.5% of 48 ESBL-producing isolates while OmpK36 was found in 35 (72.91% of 48 ESBL-producing isolates. In this study, fosfomycin and tigecycline were more effective than other antibiotics. The high prevalence of β-lactamase-producing K. pneumoniae detected in this study is of great concern, which requires infection control measures including antibacterial management and identification of β-lactamases-producing isolates.

  19. Role of porins in sensitivity of Escherichia coli to antibacterial activity of the lactoperoxidase enzyme system.

    Science.gov (United States)

    De Spiegeleer, Philipp; Sermon, Jan; Vanoirbeek, Kristof; Aertsen, Abram; Michiels, Chris W

    2005-07-01

    Lactoperoxidase is an enzyme that contributes to the antimicrobial defense in secretory fluids and that has attracted interest as a potential biopreservative for foods and other perishable products. Its antimicrobial activity is based on the formation of hypothiocyanate (OSCN-) from thiocyanate (SCN-), using H2O2 as an oxidant. To gain insight into the antibacterial mode of action of the lactoperoxidase enzyme system, we generated random transposon insertion mutations in Escherichia coli MG1655 and screened the resultant mutants for an altered tolerance of bacteriostatic concentrations of this enzyme system. Out of the ca. 5,000 mutants screened, 4 showed significantly increased tolerance, and 2 of these had an insertion, one in the waaQ gene and one in the waaO gene, whose products are involved in the synthesis of the core oligosaccharide moiety of lipopolysaccharides. Besides producing truncated lipopolysaccharides and displaying hypersensitivity to novobiocin and sodium dodecyl sulfate (SDS), these mutants were also shown by urea-SDS-polyacrylamide gel electrophoresis analysis to have reduced amounts of porins in their outer membranes. Moreover, they showed a reduced degradation of p-nitrophenyl phosphate and an increased resistance to ampicillin, two indications of a decrease in outer membrane permeability for small hydrophilic solutes. Additionally, ompC and ompF knockout mutants displayed levels of tolerance to the lactoperoxidase system similar to those displayed by the waa mutants. These results suggest that mutations which reduce the porin-mediated outer membrane permeability for small hydrophilic molecules lead to increased tolerance to the lactoperoxidase enzyme system because of a reduced uptake of OSCN-.

  20. Rapid detection of porins by matrix-assisted laser desorption/ionization-time of flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    Yanyan eHU

    2015-08-01

    Full Text Available The rapid and cost-efficient determination of carbapenem resistance is an important prerequisite for the choice of an adequate antibiotic therapy. A MALDI-TOF MS-based assay was set up to detect porins in the current study. A loss of the components of porin alone such as OmpK35/OmpK36 or together with the production of carbapenemases will augment the carbapenem resistance. Ten strains of E. coli and eight strains of K. pneumoniae were conducted for both SDS-PAGE and MALDI-TOF MS analysis. MALDI-TOF/TOF MS analysis was then performed to verify the corrospondence of proteins between SDS-PAGE and MALDI-TOF MS. The results indicated that the mass spectrum of ca. 35,000-m/z, 37,000-m/z and 38,000-m/z peaks of E. coli ATCC 25922 corresponded to OmpA, OmpC and OmpF with molecular weight of approximately ca. 38 kDa, 40 kDa and 41 kDa in SDS-PAGE gel, respectively. The band of OmpC and OmpF porins were unable to be distinguished by SDS-PAGE, whereas it was easy to be differentiated by MALDI-TOF MS. As for K. pneumoniae isolates, the mass spectrum of ca. 36,000-m/z and 38,600-m/z peaks was observed corresponding to OmpA and OmpK36 with molecular weight of approximately ca. 40 kDa and 42 kDa in SDS-PAGE gel, respectively. Porin OmpK35 was not observed in the current SDS-PAGE, while a 37,000-m/z peak was found in K. pneumoniae ATCC 13883 and carbapenem-susceptible strains by MALDI-TOF MS which was presumed to be the characteristic peak of the OmpK35 porin. Compared with SDS-PAGE, MALDI-TOF MS is able to rapidly identify the porin-deficient strains within half an hour with better sensitivity, less cost, and is easier to operate and has less interference.

  1. Structure of Carbon Nanotube Porins in Lipid Bilayers: An in Situ Small-Angle X-ray Scattering (SAXS) Study.

    Science.gov (United States)

    Tran, Ich C; Tunuguntla, Ramya H; Kim, Kyunghoon; Lee, Jonathan R I; Willey, Trevor M; Weiss, Thomas M; Noy, Aleksandr; van Buuren, Tony

    2016-07-13

    Carbon nanotube porins (CNTPs), small segments of carbon nanotubes capable of forming defined pores in lipid membranes, are important future components for bionanoelectronic devices as they could provide a robust analog of biological membrane channels. In order to control the incorporation of these CNT channels into lipid bilayers, it is important to understand the structure of the CNTPs before and after insertion into the lipid bilayer as well as the impact of such insertion on the bilayer structure. Here we employed a noninvasive in situ probe, small-angle X-ray scattering, to study the integration of CNT porins into dioleoylphosphatidylcholine bilayers. Our results show that CNTPs in solution are stabilized by a monolayer of lipid molecules wrapped around their outer surface. We also demonstrate that insertion of CNTPs into the lipid bilayer results in decreased bilayer thickness with the magnitude of this effect increasing with the concentration of CNTPs. PMID:27322135

  2. Porin alterations present in non-carbapenemase-producing Enterobacteriaceae with high and intermediate levels of carbapenem resistance in Chile.

    Science.gov (United States)

    Wozniak, Aniela; Villagra, Nicolás A; Undabarrena, Agustina; Gallardo, Natalia; Keller, Nicole; Moraga, Marcela; Román, Juan C; Mora, Guido C; García, Patricia

    2012-09-01

    The main goal of this work was to identify the mechanisms responsible for carbapenem resistance in 61 Chilean clinical isolates of Enterobacteriaceae (Enterobacter spp., Serratia marcescens, Morganella morganii, Escherichia coli and Klebsiella pneumoniae) with reduced susceptibility to at least one carbapenem (ertapenem, imipenem or meropenem). All of the isolates were analysed for the presence of carbapenemases, extended spectrum β-lactamases (ESBLs), AmpC enzymes and outer-membrane proteins. None of the isolates exhibited carbapenemase activity nor did they have any of the carbapenemase genes that were screened for. Most of the 61 strains produced at least one ESBL and/or one AmpC enzyme and either lost their porins or had altered porins according to sequence analysis. The distribution of ESBLs and AmpC enzymes was different among the species studied. Resistance in K. pneumoniae and E. coli isolates was associated with ESBLs; in M. morganii isolates, resistance was attributed to overexpression of an AmpC enzyme; and in Enterobacter spp. isolates, resistance was associated with both types of enzymes. In K. pneumoniae isolates, porin integrity was more a determinant of carbapenem resistance than the presence of ESBLs, whereas in isolates of Enterobacter spp., M. morganii and S. marcescens, the presence of an overexpressed AmpC enzyme was associated with higher imipenem and meropenem MIC values. Therefore, carbapenem resistance in Chilean isolates is not due to true carbapenemases but rather to a combination of porin loss/alteration and β-lactamase activity. The fact that carbapenemases were not detected in this study is unique, given that many countries in the region have already reported the presence of these enzymes. PMID:22700549

  3. Expressions of 3 isoforms of human progesterone receptors and porin mR-NA in uterine leiomyoma tissue%子宫平滑肌瘤组织中孕激素受体和 porin mRNA的表达

    Institute of Scientific and Technical Information of China (English)

    封全灵; 刘弘扬

    2014-01-01

    目的:探讨孕激素促进子宫平滑肌瘤形成的机制。方法:采用RT-PCR方法检测28例子宫平滑肌瘤组织(研究组)和瘤旁正常子宫平滑肌组织(对照组)中新型孕激素受体( PR)-M、PR-A、PR-B和线粒体porin mRNA的表达。结果:研究组PR-M、porin、PR-A和PR-B mRNA的表达均高于对照组(t=23.935、12.881、10.059和9.332, P<0.001);研究组中PR-M和porin mRNA的表达呈正相关(r=0.431,P=0.022)。结论:PR-M可能通过非基因组途径参与子宫平滑肌瘤的形成。%Aim:To explore the mechanism of progesterone acts on genesis of uterine leiomyoma .Methods:RT-PCR was used to detect the mRNA expressions of progesterone receptor ( PR)-M,PR-A,PR-B and porin in 28 cases of uterine leiomyoma(leiomyoma group,LG) and their corresponding myometrium (control group,CG).Results:The mRNA levels of PR-M, porin, PR-A and PR-B were higher in LG compared with those in CG (t=23.935,12.811,10.059 and 9.332,P<0.001).Pearson correlation analysis showed that there was positive correlation between PR -M and porin mRNA in LG(r=0.431,P=0.022).Conclusion:PP-M may act through genomic and nongenomic actions in the genesis and growth of uter-ine leiomyoma .

  4. Metalloido-porins: Essentiality of Nodulin 26-like intrinsic proteins in metalloid transport.

    Science.gov (United States)

    Pommerrenig, Benjamin; Diehn, Till Arvid; Bienert, Gerd Patrick

    2015-09-01

    Metalloids are a group of physiologically important elements ranging from the essential to the highly toxic. Arsenic, antimony, germanium, and tellurium are highly toxic to plants themselves and to consumers of metalloid-contaminated plants. Boron, silicon, and selenium fulfill essential or beneficial functions in plants. However, when present at high concentrations, boron and selenium cause toxicity symptoms that are detrimental to plant fitness and yield. Consequently, all plants require efficient membrane transport systems to control the uptake and extrusion of metalloids into or out of the plant and their distribution within the plant body. Several Nodulin 26-like intrinsic proteins (NIPs) that belong to the aquaporin plant water channel protein family facilitate the diffusion of uncharged metalloid species. Genetic, physiological, and molecular evidence is that NIPs from primitive to higher plants not only transport all environmentally important metalloids, but that these proteins have a major role in the uptake, translocation, and extrusion of metalloids in plants. As most of the metalloid-permeable NIP aquaporins are impermeable or are poorly permeable to water, these NIP channel proteins should be considered as physiologically essential metalloido-porins.

  5. The high-conductance channel of porin-less yeast mitochondria.

    Science.gov (United States)

    Szabó, I; Báthori, G; Wolff, D; Starc, T; Cola, C; Zoratti, M

    1995-04-12

    Patch-clamp and planar bilayer experiments on porin-less yeast mitochondria have allowed the characterization of a cationic channel activated at matrix-side positive (unphysiological) potentials. In voltage-pulse experiments, inactivation was a faster process than activation and the time constant for inactivation was more steeply dependent on voltage than the one for activation. The channel exhibited various conductance states whose occupancy depended on the applied transmembrane potential. In bilayer experiments, the presence of the pCOx-IV leader peptide induced fast gating in a voltage-dependent manner. A comparison with previously described activities suggests that the pore may coincide with the peptide-sensitive channel (PSC) (Thieffry et al. (1988) EMBO J. 7, 1449-1454) as well as with two other activities (Dihanich et al. (1989) Eur. J. Biochem. 181, 703-708; Tedeschi et al. (1987) J. Membr. Biol. 97, 21-29) assigned to the mitochondrial outer membrane. The possible relationship of this channel to the mitochondrial megachannel is discussed.

  6. Construtcion of Neisseria Gonorrhoeae Porin B Plasmid Recombinant and Its Expression in E.coli

    Institute of Scientific and Technical Information of China (English)

    SONG Qifa; LIAO Fang; YE Siying; CUI Bing; XIONG Ping

    2005-01-01

    Summary: A prokaryotic expression recombinant plasmid pET-PIB to express porin B (PIB) of Neisseria gonorrhoeae in E.coli DE3 was constructed in order to provide a basis of research in detection, prophylactic and therapeutic vaccine against the pathogen infection. The gene encoding PIB was amplified by PCR from Neisseria gonorrhoeae and cloned into prokaryotic expression plasmid pET-28a(+) to construct a pET-PIB recombinant, which was verified by restriction endonuclease and DNA sequencing. Protein PIB was expressed in E.coli DE3 induced with IPTG. The antigenicity of the expressed protein was evaluated by indirect ELISA. Rabbits were immunized with the protein and serum was collected after immunization. To assess the immunogenicity of the protein, the titer of serum to protein PIB was determined by ELISA. DNA sequence analysis showed that the nucleic acid sequence of PIB gene was 99.28 % of homology compared with that (NGPIB18) published in GenBank. A 41 kD fused protein was detected by SDS-PAGE and was proven to have reactivity with anti-PIB polyclonal antibody from mouse. A polyclonal antibody to PIB of 1:4000 titer determined by indirect ELISA was obtained from rabbit immunized with the purified product. Recombinant plasmid encoding PIB of Neisseria gonorrhoeae was constructed. Protein PIB with antigenicity and immunogenicity was successfully expressed.

  7. Metalloido-porins: Essentiality of Nodulin 26-like intrinsic proteins in metalloid transport.

    Science.gov (United States)

    Pommerrenig, Benjamin; Diehn, Till Arvid; Bienert, Gerd Patrick

    2015-09-01

    Metalloids are a group of physiologically important elements ranging from the essential to the highly toxic. Arsenic, antimony, germanium, and tellurium are highly toxic to plants themselves and to consumers of metalloid-contaminated plants. Boron, silicon, and selenium fulfill essential or beneficial functions in plants. However, when present at high concentrations, boron and selenium cause toxicity symptoms that are detrimental to plant fitness and yield. Consequently, all plants require efficient membrane transport systems to control the uptake and extrusion of metalloids into or out of the plant and their distribution within the plant body. Several Nodulin 26-like intrinsic proteins (NIPs) that belong to the aquaporin plant water channel protein family facilitate the diffusion of uncharged metalloid species. Genetic, physiological, and molecular evidence is that NIPs from primitive to higher plants not only transport all environmentally important metalloids, but that these proteins have a major role in the uptake, translocation, and extrusion of metalloids in plants. As most of the metalloid-permeable NIP aquaporins are impermeable or are poorly permeable to water, these NIP channel proteins should be considered as physiologically essential metalloido-porins. PMID:26259189

  8. Effect of porin loss on the activity of tigecycline against Klebsiella pneumoniae producing extended-spectrum beta-lactamases or plasmid-mediated AmpC-type beta-lactamases.

    Science.gov (United States)

    Conejo, M Carmen; Hernández, J Ramón; Pascual, Alvaro

    2008-07-01

    Tigecycline showed excellent in vitro activity against 50 clinical isolates of Klebsiella pneumoniae producing extended-spectrum beta-lactamases, plasmid-mediated AmpC-type beta-lactamases, or both. This activity was not affected by porin loss. Porin loss, however, did affect the activity of imipenem against strains that expressed both types of enzymes. PMID:18339509

  9. Salmonella Typhi OmpS1 and OmpS2 porins are potent protective immunogens with adjuvant properties

    Science.gov (United States)

    Moreno-Eutimio, Mario A; Tenorio-Calvo, Alejandra; Pastelin-Palacios, Rodolfo; Perez-Shibayama, Christian; Gil-Cruz, Cristina; López-Santiago, Rubén; Baeza, Isabel; Fernández-Mora, Marcos; Bonifaz, Laura; Isibasi, Armando; Calva, Edmundo; López-Macías, Constantino

    2013-01-01

    Salmonella enterica serovar Typhi (S. Typhi) is the causal agent of typhoid fever, a disease that primarily affects developing countries. Various antigens from this bacterium have been reported to be targets of the immune response. Recently, the S. Typhi genome has been shown to encode two porins – OmpS1 and OmpS2 – which are expressed at low levels under in vitro culture conditions. In this study, we demonstrate that immunizing mice with either OmpS1 or OmpS2 induced production of specific, long-term antibody titres and conferred protection against S. Typhi challenge; in particular, OmpS1 was more immunogenic and conferred greater protective effects than OmpS2. We also found that OmpS1 is a Toll-like receptor 4 (TLR4) agonist, whereas OmpS2 is a TLR2 and TLR4 agonist. Both porins induced the production of tumour necrosis factor and interleukin-6, and OmpS2 was also able to induce interleukin-10 production. Furthermore, OmpS1 induced the over-expression of MHC II molecules in dendritic cells and OmpS2 induced the over-expression of CD40 molecules in macrophages and dendritic cells. Co-immunization of OmpS1 or OmpS2 with ovalbumin (OVA) increased anti-OVA antibody titres, the duration and isotype diversity of the OVA-specific antibody response, and the proliferation of T lymphocytes. These porins also had adjuvant effects on the antibody response when co-immunized with either the Vi capsular antigen from S. Typhi or inactivated 2009 pandemic influenza A(H1N1) virus [A(H1N1)pdm09]. Taken together, the data indicate that OmpS1 and OmpS2, despite being expressed at low levels under in vitro culture conditions, are potent protective immunogens with intrinsic adjuvant properties. PMID:23432484

  10. Salmonella Typhi OmpS1 and OmpS2 porins are potent protective immunogens with adjuvant properties.

    Science.gov (United States)

    Moreno-Eutimio, Mario A; Tenorio-Calvo, Alejandra; Pastelin-Palacios, Rodolfo; Perez-Shibayama, Christian; Gil-Cruz, Cristina; López-Santiago, Rubén; Baeza, Isabel; Fernández-Mora, Marcos; Bonifaz, Laura; Isibasi, Armando; Calva, Edmundo; López-Macías, Constantino

    2013-08-01

    Salmonella enterica serovar Typhi (S. Typhi) is the causal agent of typhoid fever, a disease that primarily affects developing countries. Various antigens from this bacterium have been reported to be targets of the immune response. Recently, the S. Typhi genome has been shown to encode two porins--OmpS1 and OmpS2--which are expressed at low levels under in vitro culture conditions. In this study, we demonstrate that immunizing mice with either OmpS1 or OmpS2 induced production of specific, long-term antibody titres and conferred protection against S. Typhi challenge; in particular, OmpS1 was more immunogenic and conferred greater protective effects than OmpS2. We also found that OmpS1 is a Toll-like receptor 4 (TLR4) agonist, whereas OmpS2 is a TLR2 and TLR4 agonist. Both porins induced the production of tumour necrosis factor and interleukin-6, and OmpS2 was also able to induce interleukin-10 production. Furthermore, OmpS1 induced the over-expression of MHC II molecules in dendritic cells and OmpS2 induced the over-expression of CD40 molecules in macrophages and dendritic cells. Co-immunization of OmpS1 or OmpS2 with ovalbumin (OVA) increased anti-OVA antibody titres, the duration and isotype diversity of the OVA-specific antibody response, and the proliferation of T lymphocytes. These porins also had adjuvant effects on the antibody response when co-immunized with either the Vi capsular antigen from S. Typhi or inactivated 2009 pandemic influenza A(H1N1) virus [A(H1N1)pdm09]. Taken together, the data indicate that OmpS1 and OmpS2, despite being expressed at low levels under in vitro culture conditions, are potent protective immunogens with intrinsic adjuvant properties.

  11. Kahden käden työtä : Lähetys ja kansainvälinen diakonia Länsi-Porin seurakunnan nuorten illoissa

    OpenAIRE

    Lahti, Tiia

    2010-01-01

    Lahti, Tiia. Kahden käden työtä. Lähetys ja kansainvälinen diakonia Länsi-Porin seurakunnan nuorten illoissa. Pori, kevät 2010. 39 sivua. 4 liitettä. Diakonia-ammattikorkeakoulu. Diak Länsi Pori. Sosiaalialan koulutusohjelma. Diakonisen sosiaalityön suuntautumisvaihtoehto, sosionomi (AMK) + diakoni. Opinnäytetyö oli kehittämishanke, joka toteutettiin yhteistyössä Länsi-Porin seurakunnan kanssa. Opinnäytetyön tavoitteena oli saada lähetys ja kansainvälinen diakonia osaksi seurakunnan n...

  12. Protein AQ_1862 from the Hyperthermophilic Bacterium Aquifex aeolicus Is a Porin and Contains Two Conductance Pathways of Different Selectivity

    OpenAIRE

    Wedemeyer, Ulrike; Peng, Guohong; Michel, Hartmut; Hartung, Klaus

    2007-01-01

    The “hypothetical protein” AQ_1862 was isolated from the membrane fraction of Aquifex aeolicus and identified as the major porin. In experiments with one conducting unit (molecule) a conductance of 1.4 nS was observed in 0.1 M KCl at pH 7.5. This stable (basic) conductance was superimposed by conductance fluctuations of ∼0.25 nS. Because both events were always observed simultaneously, it is suggested that they are caused by the same molecular entity. Nonetheless they show very different prop...

  13. Characteristics of Sucrose Transport through the Sucrose-Specific Porin ScrY Studied by Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Liping eSun

    2016-02-01

    Full Text Available Sucrose-specific porin (ScrY is a transmembrane protein that allows for the uptake of sucrose under growth-limiting conditions. The crystal structure of ScrY was resolved before by X-ray crystallography, both in its uncomplexed form and with bound sucrose. However, little is known about the molecular characteristics of the transport mechanism of ScrY. To date, there has not yet been any clear demonstration for sucrose transport through the ScrY.Here, the dynamics of the ScrY trimer embedded in a phospholipid bilayer as well as the characteristics of sucrose translocation were investigated by means of atomistic molecular dynamics (MD simulations. The potential of mean force (PMF for sucrose translocation through the pore showed two main energy barriers within the constriction region of ScrY. Energy decomposition allowed to pinpoint three aspartic acids as key residues opposing the passage of sucrose, all located within the L3 loop. Mutation of two aspartic acids to uncharged residues resulted in an accordingly modified electrostatics and decreased PMF barrier. The chosen methodology and results will aid in the design of porins with modified transport specificities.

  14. Characteristics of Sucrose Transport through the Sucrose-Specific Porin ScrY Studied by Molecular Dynamics Simulations.

    Science.gov (United States)

    Sun, Liping; Bertelshofer, Franziska; Greiner, Günther; Böckmann, Rainer A

    2016-01-01

    Sucrose-specific porin (ScrY) is a transmembrane protein that allows for the uptake of sucrose under growth-limiting conditions. The crystal structure of ScrY was resolved before by X-ray crystallography, both in its uncomplexed form and with bound sucrose. However, little is known about the molecular characteristics of the transport mechanism of ScrY. To date, there has not yet been any clear demonstration for sucrose transport through the ScrY. Here, the dynamics of the ScrY trimer embedded in a phospholipid bilayer as well as the characteristics of sucrose translocation were investigated by means of atomistic molecular dynamics (MD) simulations. The potential of mean force (PMF) for sucrose translocation through the pore showed two main energy barriers within the constriction region of ScrY. Energy decomposition allowed to pinpoint three aspartic acids as key residues opposing the passage of sucrose, all located within the L3 loop. Mutation of two aspartic acids to uncharged residues resulted in an accordingly modified electrostatics and decreased PMF barrier. The chosen methodology and results will aid in the design of porins with modified transport specificities. PMID:26913282

  15. Alcohol disrupts sleep homeostasis.

    Science.gov (United States)

    Thakkar, Mahesh M; Sharma, Rishi; Sahota, Pradeep

    2015-06-01

    Alcohol is a potent somnogen and one of the most commonly used "over the counter" sleep aids. In healthy non-alcoholics, acute alcohol decreases sleep latency, consolidates and increases the quality (delta power) and quantity of NREM sleep during the first half of the night. However, sleep is disrupted during the second half. Alcoholics, both during drinking periods and during abstinences, suffer from a multitude of sleep disruptions manifested by profound insomnia, excessive daytime sleepiness, and altered sleep architecture. Furthermore, subjective and objective indicators of sleep disturbances are predictors of relapse. Finally, within the USA, it is estimated that societal costs of alcohol-related sleep disorders exceeds $18 billion. Thus, although alcohol-associated sleep problems have significant economic and clinical consequences, very little is known about how and where alcohol acts to affect sleep. In this review, we have described our attempts to unravel the mechanism of alcohol-induced sleep disruptions. We have conducted a series of experiments using two different species, rats and mice, as animal models. We performed microdialysis, immunohistochemical, pharmacological, sleep deprivation and lesion studies which suggest that the sleep-promoting effects of alcohol may be mediated via alcohol's action on the mediators of sleep homeostasis: adenosine (AD) and the wake-promoting cholinergic neurons of the basal forebrain (BF). Alcohol, via its action on AD uptake, increases extracellular AD resulting in the inhibition of BF wake-promoting neurons. Since binge alcohol consumption is a highly prevalent pattern of alcohol consumption and disrupts sleep, we examined the effects of binge drinking on sleep-wakefulness. Our results suggest that disrupted sleep homeostasis may be the primary cause of sleep disruption observed following binge drinking. Finally, we have also shown that sleep disruptions observed during acute withdrawal, are caused due to impaired

  16. Disrupting Vestibular Activity Disrupts Body Ownership.

    Science.gov (United States)

    Hoover, Adria E N; Harris, Laurence R

    2015-01-01

    People are more sensitive at detecting asynchrony between a self-generated movement and visual feedback concerning that movement when the movement is viewed from a first-person perspective. We call this the 'self-advantage' and interpret it as an objective measure of self. Here we ask if disruption of the vestibular system in healthy individuals affects the self-advantage. Participants performed finger movements while viewing their hand in a first-person ('self') or third-person ('other') perspective and indicated which of two periods (one with minimum delay and the other with an added delay of 33-264 ms) was delayed. Their sensitivity to the delay was calculated from the psychometric functions obtained. During the testing, disruptive galvanic vestibular stimulation (GVS) was applied in five-minute blocks interleaved with five minutes of no stimulation for a total of 40 min. We confirmed the self-advantage under no stimulation (31 ms). In the presence of disruptive GVS this advantage disappeared and there was no longer a difference in performance between perspectives. The threshold delay for the 'other' perspective was not affected by the GVS. These results suggest that an intact vestibular signal is required to distinguish 'self' from 'other' and to maintain a sense of body ownership. PMID:26595957

  17. Endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Mandrup, Karen

    . To improve knowledge on possible influences of endocrine disrupters on female reproductive system, the effects of EDCs on genital malformations in females and the development of mammary glands were studied in the present project. AIMS: The aims for the studies on male and female mammary gland development......BACKGROUND: Endocrine disrupting chemicals (EDCs) may contribute to reproductive changes in boys in the Western world, however, less is known about influence of EDCs in women. The incidence of precocious breast development is increasing in USA and Europe and mammary gland development has been...... suggested as particularly sensitive to endocrine disruption. Mammary gland examination in toxicological studies may be useful for improving knowledge on possible influences of EDCs on human mammary glands and also be useful for detection of endocrine disrupting effects of chemicals as part of safety testing...

  18. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    This paper analyzes how external search is affected by strategic interest alignment among knowledge sources. I focus on misalignment arising from the heterogeneous effects of disruptive technologies by analyzing the influence of incumbents on 2,855 non-incumbents? external knowledge search efforts....... The efforts most likely to solve innovation problems obtained funding from the European Commission?s 7th Framework Program (2007-2013). The results show that involving incumbents improves search in complementary technologies, while demoting it when strategic interests are misaligned in disruptive technologies....... However, incumbent sources engaged in capability reconfiguration to accommodate disruption improve search efforts in disruptive technologies. The paper concludes that the value of external sources is contingent on more than their knowledge. Specifically, interdependence of sources in search gives rise...

  19. Mitochondrial Porin Isoform AtVDAC1 Regulates the Competence of Arabidopsis thaliana to Agrobacterium-Mediated Genetic Transformation

    Science.gov (United States)

    Kwon, Tackmin

    2016-01-01

    The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background. Genetic complementation of Arabidopsis vdac1 mutants and yeast porin1-deficient strain with members of the AtVDAC gene family revealed that AtVDAC1 is required for Agrobacterium-mediated transformation, and there is weak functional redundancy between AtVDAC1 and AtVDAC3, which is independent of porin activity. Furthermore, atvdac1 mutants were deficient in transient and stable transformation by Agrobacterium, suggesting that AtVDAC1 is involved in the early stages of Agrobacterium infection prior to transferred-DNA (T-DNA) integration. Transgenic plants overexpressing AtVDAC1 not only complemented the phenotypes of the atvdac1 mutant, but also showed high efficiency of transient T-DNA gene expression; however, the efficiency of stable transformation was not affected. Moreover, the effect of phytohormone treatment on competence to Agrobacterium was compromised in atvdac1 mutants. These data indicate that AtVDAC1 regulates the competence of Arabidopsis to Agrobacterium infection. PMID:27643450

  20. The disruption management model.

    Science.gov (United States)

    McAlister, James

    2011-10-01

    Within all organisations, business continuity disruptions present a set of dilemmas that managers may not have dealt with before in their normal daily duties. The disruption management model provides a simple but effective management tool to enable crisis management teams to stay focused on recovery in the midst of a business continuity incident. The model has four chronological primary headlines, which steer the team through a quick-time crisis decision-making process. The procedure facilitates timely, systematic, rationalised and justified decisions, which can withstand post-event scrutiny. The disruption management model has been thoroughly tested within an emergency services environment and is proven to significantly support clear and concise decision making in a business continuity context. PMID:22130341

  1. Changing circumstances, disrupting habits.

    Science.gov (United States)

    Wood, Wendy; Witt, Melissa Guerrero; Tam, Leona

    2005-06-01

    The present research investigated the mechanisms guiding habitual behavior, specifically, the stimulus cues that trigger habit performance. When usual contexts for performance change, habits cannot be cued by recurring stimuli, and performance should be disrupted. Thus, the exercising, newspaper reading, and TV watching habits of students transferring to a new university were found to survive the transfer only when aspects of the performance context did not change (e.g., participants continued to read the paper with others). In some cases, the disruption in habits also placed behavior under intentional control so that participants acted on their current intentions. Changes in circumstances also affected the favorability of intentions, but changes in intentions alone could not explain the disruption of habits. Furthermore, regardless of whether contexts changed, nonhabitual behavior was guided by intentions. PMID:15982113

  2. Emerging and Disruptive Technologies

    Science.gov (United States)

    2016-01-01

    Several emerging or disruptive technologies can be identified that might, at some point in the future, displace established laboratory medicine technologies and practices. These include increased automation in the form of robots, 3-D printing, technology convergence (e.g., plug-in glucose meters for smart phones), new point-of-care technologies (e.g., contact lenses with sensors, digital and wireless enabled pregnancy tests) and testing locations (e.g., Retail Health Clinics, new at-home testing formats), new types of specimens (e.g., cell free DNA), big biology/data (e.g., million genome projects), and new regulations (e.g., for laboratory developed tests). In addition, there are many emerging technologies (e.g., planar arrays, mass spectrometry) that might find even broader application in the future and therefore also disrupt current practice. One interesting source of disruptive technology may prove to be the Qualcomm Tricorder XPrize, currently in its final stages. PMID:27683538

  3. The disruption management model.

    Science.gov (United States)

    McAlister, James

    2011-10-01

    Within all organisations, business continuity disruptions present a set of dilemmas that managers may not have dealt with before in their normal daily duties. The disruption management model provides a simple but effective management tool to enable crisis management teams to stay focused on recovery in the midst of a business continuity incident. The model has four chronological primary headlines, which steer the team through a quick-time crisis decision-making process. The procedure facilitates timely, systematic, rationalised and justified decisions, which can withstand post-event scrutiny. The disruption management model has been thoroughly tested within an emergency services environment and is proven to significantly support clear and concise decision making in a business continuity context.

  4. Sustainable Disruption Management

    DEFF Research Database (Denmark)

    Vaaben, Bo Valdemar

    The world we live in is globalized. Goods are seldom made in the place where they are used or consumed, and we do increasingly travel to other countries for either business or pleasure. In our everyday lives we rely on well-functioning global transportations systems to continue the standard......, such as e.g. technical problems or congestions are also typical causes of delays. Returning a transportation system to its original plan of operation is referred to as Disruption Management. Disruptions are, however, not the only cause of concern to the transportation industry. Fuel is becoming...... when managing recovery from disruptions. The underlying work of this thesis is carried out as an industrial PhD project in co-operation with the company Jeppesen, which have the airline industry as its primary area of business and the maritime industry as its secondary area. For this reason the thesis...

  5. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    Extant research on external knowledge search and open innovation assumes that collaborators are aligned in their strategic interests towards solving innovation problems. However, disruptive innovation is known to threaten the competitive advantage of incumbent firms, thereby creating a potential...... conflict of interest between these firms and their collaborators. This paper explores the extent to which strategic interests influence joint problem solving in both complementary and disruptive technologies by analyzing the effects of incumbent collaboration. The analysis disentangles inability...... and strategic intent to find that non-incumbents experience suppression of problem solving likelihood within disruptive technologies when incumbent collaborators are not strategically committed. The paper contributes to extant theory by showing the influence of firms’ underlying strategic interests...

  6. Interruptions disrupt reading comprehension.

    Science.gov (United States)

    Foroughi, Cyrus K; Werner, Nicole E; Barragán, Daniela; Boehm-Davis, Deborah A

    2015-06-01

    Previous research suggests that being interrupted while reading a text does not disrupt the later recognition or recall of information from that text. This research is used as support for Ericsson and Kintsch's (1995) long-term working memory (LT-WM) theory, which posits that disruptions while reading (e.g., interruptions) do not impair subsequent text comprehension. However, to fully comprehend a text, individuals may need to do more than recognize or recall information that has been presented in the text at a later time. Reading comprehension often requires individuals to connect and synthesize information across a text (e.g., successfully identifying complex topics such as themes and tones) and not just make a familiarity-based decision (i.e., recognition). The goal for this study was to determine whether interruptions while reading disrupt reading comprehension when the questions assessing comprehension require participants to connect and synthesize information across the passage. In Experiment 1, interruptions disrupted reading comprehension. In Experiment 2, interruptions disrupted reading comprehension but not recognition of information from the text. In Experiment 3, the addition of a 15-s time-out prior to the interruption successfully removed these negative effects. These data suggest that the time it takes to process the information needed to successfully comprehend text when reading is greater than that required for recognition. Any interference (e.g., an interruption) that occurs during the comprehension process may disrupt reading comprehension. This evidence supports the need for transient activation of information in working memory for successful text comprehension and does not support LT-WM theory. PMID:25867225

  7. Proinflammatory signal transduction pathway induced by Shigella flexneri porins in caco-2 cells Via de transdução de sinal pró-inflamatória induzida por porinas de Shigella flexneri em células caco-2

    Directory of Open Access Journals (Sweden)

    Grimaldi Elena

    2009-09-01

    Full Text Available The recognition of bacterial components on the intestinal epithelial cells occurs through the toll-like receptors and is followed by the induction of an effective innate immune response. We analyzed receptor expression and signaling pathways involved in activation of human colon adenocarcinoma cells after stimulation with porins and LPS of Shigella flexneri. We also analyzed the expression and production of some cytokines, of intercellular adhesion molecule-1, of antimicrobial peptides human ²-defensins, and of the inducible form of nitric oxide synthase. Our data demonstrate that TLR2 is involved in porin recognition, whereas TLR4 with MD2, is required for LPS recognition.O reconhecimento de componentes bacterianos nas células epiteliais intestinais ocorre através de receptores toll-like e é seguido de indução de uma resposta imune inata efetiva. Neste estudo foram analisadas as vias de expressão do receptor e sinalização envolvidas na ativação de células humanas de adenocarcinoma do colon após a estimulação com porinas e LPS de Shigella flexneri. Foram também analisadas a expressão e produção de algumas citoquinas, da molécula -1 de adesão intercelular, de ²-defensinas humanas a peptídios antimicrobianos e da forma indutível de oxido nítrico sintase. Os resultados demonstraram que TLR-2 está envolvido no reconhecimento de porinas, enquanto TLR4 com MD2 é necessário para o reconhecimento de LPS.

  8. Identification and characterization of a novel porin family highlights a major difference in the outer membrane of chlamydial symbionts and pathogens.

    Directory of Open Access Journals (Sweden)

    Karin Aistleitner

    Full Text Available The Chlamydiae constitute an evolutionary well separated group of intracellular bacteria comprising important pathogens of humans as well as symbionts of protozoa. The amoeba symbiont Protochlamydia amoebophila lacks a homologue of the most abundant outer membrane protein of the Chlamydiaceae, the major outer membrane protein MOMP, highlighting a major difference between environmental chlamydiae and their pathogenic counterparts. We recently identified a novel family of putative porins encoded in the genome of P. amoebophila by in silico analysis. Two of these Protochlamydiaouter membrane proteins, PomS (pc1489 and PomT (pc1077, are highly abundant in outer membrane preparations of this organism. Here we show that all four members of this putative porin family are toxic when expressed in the heterologous host Escherichia coli. Immunofluorescence analysis using antibodies against heterologously expressed PomT and PomS purified directly from elementary bodies, respectively, demonstrated the location of both proteins in the outer membrane of P. amoebophila. The location of the most abundant protein PomS was further confirmed by immuno-transmission electron microscopy. We could show that pomS is transcribed, and the corresponding protein is present in the outer membrane throughout the complete developmental cycle, suggesting an essential role for P. amoebophila. Lipid bilayer measurements demonstrated that PomS functions as a porin with anion-selectivity and a pore size similar to the Chlamydiaceae MOMP. Taken together, our results suggest that PomS, possibly in concert with PomT and other members of this porin family, is the functional equivalent of MOMP in P. amoebophila. This work contributes to our understanding of the adaptations of symbiotic and pathogenic chlamydiae to their different eukaryotic hosts.

  9. Disruptive Co-Creation?

    DEFF Research Database (Denmark)

    Butler, Ivan; Christensen, David

    set up to foster innovative partnerships between civil society organizations, businesses and academia with the objective of supporting disruptive business model innovation in co-creation processes across these sectors. This paper delves into state-of-the-art concerning literature pertinent...

  10. Bacterial Vaginosis

    Science.gov (United States)

    ... 586. Related Content STDs during Pregnancy Fact Sheet Pregnancy and HIV, Viral Hepatitis, and STD Prevention Pelvic Inflammatory Disease ( ... Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ... STDs See Also Pregnancy Reproductive ...

  11. Bacterial Meningitis

    Science.gov (United States)

    ... Schedules Preteen & Teen Vaccines Meningococcal Disease Sepsis Bacterial Meningitis Recommend on Facebook Tweet Share Compartir On this ... serious disease. Laboratory Methods for the Diagnosis of Meningitis This manual summarizes laboratory methods used to isolate, ...

  12. Adaptive and Mutational Resistance: Role of Porins and Efflux Pumps in Drug Resistance

    OpenAIRE

    Fernández, Lucía; Robert E W Hancock

    2012-01-01

    Summary: The substantial use of antibiotics in the clinic, combined with a dearth of new antibiotic classes, has led to a gradual increase in the resistance of bacterial pathogens to these compounds. Among the various mechanisms by which bacteria endure the action of antibiotics, those affecting influx and efflux are of particular importance, as they limit the interaction of the drug with its intracellular targets and, consequently, its deleterious effects on the cell. This review evaluates t...

  13. Endocrine disrupting compounds

    DEFF Research Database (Denmark)

    Bøgh, I B; Christensen, P; Dantzer, V;

    2001-01-01

    With the growing concern that environmental chemicals might impair human and animal fertility, it is important to investigate the possible influence of these substances on sexual differentiation and genital development of mammals. Many of these substances are suspected to interfere with endocrine...... processes, and exposure during critical periods of prenatal development might affect reproductive performance over several generations. Alkylphenols and their metabolites are lipophilic substances exerting apparent estrogenic action in in vitro and in vivo testing systems. With the widespread industrial use...... or embryo models for the evaluation of possible consequences of human exposure to endocrine disrupting compounds is discussed. Furthermore, possible consequences of exposure to endocrine disrupting compounds for the embryo transfer industry are addressed....

  14. Celibacy and Family Disruption

    OpenAIRE

    Emaletdinov B. M.

    2013-01-01

    Causes for celibacy, divorces and successful marriage are discussed in the article. Absence of true love and inability to build and keep it are the main reasons for family disruption. Amorousness, immature love and various forms of false or flawed love substitute the true feeling. It is caused by increased women’s independence, loss of mutual understanding and trust (due to infidelity or jealousy), incompatibility of characters or values. Celibacy is often conditioned by physical disability, ...

  15. Search and Disrupt

    OpenAIRE

    Ørding Olsen, Anders

    2015-01-01

    This paper analyzes how external search is affected by strategic interest alignment among knowledge sources. I focus on misalignment arising from the heterogeneous effects of disruptive technologies by analyzing the influence of incumbents on 2,855 non-incumbents? external knowledge search efforts. The efforts most likely to solve innovation problems obtained funding from the European Commission?s 7th Framework Program (2007-2013). The results show that involving incumbents improv...

  16. Schematically disruptive game design

    OpenAIRE

    Howell, Peter

    2011-01-01

    Many games focus their resources at satiating player ‘needs’, and meeting perceived expectations that players have of how games should behave and of what constitutes enjoyable, gratifying gameplay. This paper outlines an alternate position on game design – one which focuses on disrupting these expectations, on designing games that players cannot succeed in simply by relying on their pre-acquired gameplay experiences. A critique of current game design trends is offered, and possible future out...

  17. Bacterial carbonatogenesis

    International Nuclear Information System (INIS)

    Several series of experiments in the laboratory as well as in natural conditions teach that the production of carbonate particles by heterotrophic bacteria follows different ways. The 'passive' carbonatogenesis is generated by modifications of the medium that lead to the accumulation of carbonate and bicarbonate ions and to the precipitation of solid particles. The 'active' carbonatogenesis is independent of the metabolic pathways. The carbonate particles are produced by ionic exchanges through the cell membrane following still poorly known mechanisms. Carbonatogenesis appears to be the response of heterotrophic bacterial communities to an enrichment of the milieu in organic matter. The active carbonatogenesis seems to start first. It is followed by the passive one which induces the growth of initially produced particles. The yield of heterotrophic bacterial carbonatogenesis and the amounts of solid carbonates production by bacteria are potentially very high as compared to autotrophic or chemical sedimentation from marine, paralic or continental waters. Furthermore, the bacterial processes are environmentally very ubiquitous; they just require organic matter enrichment. Thus, apart from purely evaporite and autotrophic ones, all Ca and/or Mg carbonates must be considered as from heterotrophic bacterial origin. By the way, the carbon of carbonates comes from primary organic matter. Such considerations ask questions about some interpretations from isotopic data on carbonates. Finally, bacterial heterotrophic carbonatogenesis appears as a fundamental phase in the relationships between atmosphere and lithosphere and in the geo-biological evolution of Earth. (author)

  18. Inquiry-Based Examination of Chemical Disruption of Bacterial Biofilms

    Science.gov (United States)

    Redelman, Carly V.; Hawkins, Misty A. W.; Drumwright, Franklin R.; Ransdell, Beverly; Marrs, Kathleen; Anderson, Gregory G.

    2012-01-01

    Inquiry-based instruction in the sciences has been demonstrated as a successful educational strategy to use for both high school and college science classrooms. As participants in the NSF Graduate STEM Fellows in K-12 Education (GK-12) Program, we were tasked with creating novel inquiry-based activities for high school classrooms. As a way to…

  19. Loss of elongation factor P disrupts bacterial outer membrane integrity

    DEFF Research Database (Denmark)

    Zou, S Betty; Hersch, Steven J; Roy, Hervé;

    2012-01-01

    Elongation factor P (EF-P) is posttranslationally modified at a conserved lysyl residue by the coordinated action of two enzymes, PoxA and YjeK. We have previously established the importance of this modification in Salmonella stress resistance. Here we report that, like poxA and yjeK mutants......, Salmonella strains lacking EF-P display increased susceptibility to hypoosmotic conditions, antibiotics, and detergents and enhanced resistance to the compound S-nitrosoglutathione. The susceptibility phenotypes are largely explained by the enhanced membrane permeability of the efp mutant, which exhibits...... background ameliorates the detergent, antibiotic, and osmosensitivity phenotypes and restores wild-type permeability to NPN. Our data support a role for EF-P in the translational regulation of a limited number of proteins that, when perturbed, renders the cell susceptible to stress by the adventitious...

  20. Laser Microbial Killing and Biofilm Disruption

    Science.gov (United States)

    Krespi, Yosef P.; Kizhner, Victor

    2009-06-01

    Objectives: To analyze the ability of NIR lasers to reduce bacterial load and demonstrate the capability of fiber-based Q-switched Nd:YAG laser disrupting biofilm. Study Design: NIR diode laser was tested in vitro and in vivo using pathogenic microorganisms (S. aureus, S. pneumoniae, P. aeruginosa). In addition biofilms were grown from clinical Pseudomonas isolates and placed in culture plates, screws, tympanostomy tubes and PET sutures. Methods: In the animal experiments acute rhinosinusitis model was created by packing the rabbit nose with bacteria soaked solution. The nasal pack was removed in two days and nose was exposed to laser irradiation. A 940 nm diode laser with fiber diffuser was used. Nasal cultures were obtained before and after the laser treatments. Animals were sacrificed fifteen days following laser treatment and bacteriologic/histologic results analyzed. Q-switched Nd:YAG laser generated shockwave pulses were delivered on biofilm using special probes over culture plates, screws, tubes, and PET sutures for the biofilm experiments. Results: Average of two log bacteria reduction was achieved with NIR laser compared to controls. Histologic studies demonstrated preservation of tissue integrity without significant damage to mucosa. Biofilms were imaged before, during and after treatment using a confocal microscope. During laser-generated shockwave application, biofilm was initially seen to oscillate and eventually break off. Large and small pieces of biofilm were totally and instantly removed from the surface to which they were attached in seconds. Conclusions: Significant bacterial reduction was achieved with NIR laser therapy in this experimental in vitro and animal study. In addition we disrupted Pseudomonas aeruginosa biofilms using Q-switched Nd:YAG laser and special probes generating plasma and shockwave. This new and innovative method of bacteria killing and biofilm disruption without injuring host tissue may have clinical application in the

  1. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  2. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    1994-01-01

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation, mea

  3. Disruption - Access cards service

    CERN Multimedia

    2014-01-01

    We would like to inform you that between 10 November and 15 December 2014, the access cards service in Building 55 will be disrupted, as the GS Department has decided to improve the facilities for users of this building. During the work, you will find the registration, biometric registration and dosimeter exchange services on the second floor of Building 55 and the vehicle sticker service on the ground floor along with the access cards service. We thank you for your understanding and apologise for any inconvenience caused.

  4. Celibacy and Family Disruption

    Directory of Open Access Journals (Sweden)

    Emaletdinov B. M.

    2013-01-01

    Full Text Available Causes for celibacy, divorces and successful marriage are discussed in the article. Absence of true love and inability to build and keep it are the main reasons for family disruption. Amorousness, immature love and various forms of false or flawed love substitute the true feeling. It is caused by increased women’s independence, loss of mutual understanding and trust (due to infidelity or jealousy, incompatibility of characters or values. Celibacy is often conditioned by physical disability, revaluation of freedom and independence, huge requirements to partners, consumer attitude to life, infertility, alcohol and drug abuse, abnormalities in personality and sexuality.

  5. Relativistic tidal disruption events

    Directory of Open Access Journals (Sweden)

    Levan A.

    2012-12-01

    Full Text Available In March 2011 Swift detected an extremely luminous and long-lived outburst from the nucleus of an otherwise quiescent, low luminosity (LMC-like galaxy. Named Swift J1644+57, its combination of high-energy luminosity (1048 ergs s−1 at peak, rapid X-ray variability (factors of >100 on timescales of 100 seconds and luminous, rising radio emission suggested that we were witnessing the birth of a moderately relativistic jet (Γ ∼ 2 − 5, created when a star is tidally disrupted by the supermassive black hole in the centre of the galaxy. A second event, Swift J2058+0516, detected two months later, with broadly similar properties lends further weight to this interpretation. Taken together this suggests that a fraction of tidal disruption events do indeed create relativistic outflows, demonstrates their detectability, and also implies that low mass galaxies can host massive black holes. Here, I briefly outline the observational properties of these relativistic tidal flares observed last year, and their evolution over the first year since their discovery.

  6. Disruptions in the TFTR tokamak

    International Nuclear Information System (INIS)

    For a successful reactor, it will be useful to predict the occurrence of disruptions and to understand disruption effects including how a plasma disrupts onto the wall and how reproducibly it does so. Studies of disruptions on TFTR at both high-βpol and high-density have shown that, in both types, a fast growing m/n=1/1 mode plays an important role. In highdensity disruptions, a newly observed fast m/n = 1/1 mode occurs early in the thermal decay phase. For the first time in TFTR q-profile measurements just prior to disruptions have been made. Experimental studies of heat deposition patterns on the first wall of TFTR due to disruptions have provided information on MHD phenomena prior to or during the disruption, how the energy is released to the wall, and the reproducibility of the heat loads from disruptions. This information is important in the design of future devices such as ITER. Several new processes of runaway electron generation are theoretically suggested and their application to TFTR and ITER is considered, together with a preliminary assessment of x-ray data from runaways generated during disruptions

  7. Bacterial Ecology

    DEFF Research Database (Denmark)

    Fenchel, Tom

    2011-01-01

    Bacterial ecology is concerned with the interactions between bacteria and their biological and nonbiological environments and with the role of bacteria in biogeochemical element cycling. Many fundamental properties of bacteria are consequences of their small size. Thus, they can efficiently exploit...... biogeochemical processes are carried exclusively by bacteria. * Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life....

  8. [Bacterial vaginosis].

    Science.gov (United States)

    Romero Herrero, Daniel; Andreu Domingo, Antonia

    2016-07-01

    Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists. PMID:27474242

  9. A novel outer-membrane anion channel (porin) as part of a putatively two-component transport system for 4-toluenesulphonate in Comamonas testosteroni T-2

    OpenAIRE

    Mampel, Jörg; Maier, Elke; Tralau, Tewes; Ruff, Jürgen; Benz, Roland; Cook, Alasdair M.

    2004-01-01

    Inducible mineralization of TSA (4-toluenesulphonate) by Comamonas testosteroni T-2 is initiated by a secondary transport system, followed by oxygenation and oxidation by TsaMBCD to 4-sulphobenzoate under the regulation of TsaR and TsaQ. Evidence is presented for a novel, presumably two-component transport system (TsaST). It is proposed that TsaT, an outer-membrane porin, formed an anion-selective channel that works in co-operation with the putative secondary transporter, TsaS, located in the...

  10. Disruptive camouflage impairs object recognition

    OpenAIRE

    Richard J. Webster; Hassall, Christopher; Herdman, Chris M.; Godin, Jean-Guy J.; Sherratt, Thomas N.

    2013-01-01

    Whether hiding from predators, or avoiding battlefield casualties, camouflage is widely employed to prevent detection. Disruptive coloration is a seemingly well-known camouflage mechanism proposed to function by breaking up an object's salient features (for example their characteristic outline), rendering objects more difficult to recognize. However, while a wide range of animals are thought to evade detection using disruptive patterns, there is no direct experimental evidence that disruptive...

  11. Contribution of efflux pumps, porins, and β-lactamases to multidrug resistance in clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Rumbo, C; Gato, E; López, M; Ruiz de Alegría, C; Fernández-Cuenca, F; Martínez-Martínez, L; Vila, J; Pachón, J; Cisneros, J M; Rodríguez-Baño, J; Pascual, A; Bou, G; Tomás, M

    2013-11-01

    We investigated the mechanisms of resistance to carbapenems, aminoglycosides, glycylcyclines, tetracyclines, and quinolones in 90 multiresistant clinical strains of Acinetobacter baumannii isolated from two genetically unrelated A. baumannii clones: clone PFGE-ROC-1 (53 strains producing the OXA-58 β-lactamase enzyme and 18 strains with the OXA-24 β-lactamase) and clone PFGE-HUI-1 (19 strains susceptible to carbapenems). We used real-time reverse transcriptase PCR to correlate antimicrobial resistance (MICs) with expression of genes encoding chromosomal β-lactamases (AmpC and OXA-51), porins (OmpA, CarO, Omp33, Dcap-like, OprB, Omp25, OprC, OprD, and OmpW), and proteins integral to six efflux systems (AdeABC, AdeIJK, AdeFGH, CraA, AbeM, and AmvA). Overexpression of the AdeABC system (level of expression relative to that by A. baumannii ATCC 17978, 30- to 45-fold) was significantly associated with resistance to tigecycline, minocycline, and gentamicin and other biological functions. However, hyperexpression of the AdeIJK efflux pump (level of expression relative to that by A. baumannii ATCC 17978, 8- to 10-fold) was significantly associated only with resistance to tigecycline and minocycline (to which the TetB efflux system also contributed). TetB and TetA(39) efflux pumps were detected in clinical strains and were associated with resistance to tetracyclines and doxycycline. The absence of the AdeABC system and the lack of expression of other mechanisms suggest that tigecycline-resistant strains of the PFGE-HUI-1 clone may be associated with a novel resistance-nodulation-cell efflux pump (decreased MICs in the presence of the inhibitor Phe-Arg β-naphthylamide dihydrochloride) and the TetA(39) system. PMID:23939894

  12. Repartnering after First Union Disruption

    Science.gov (United States)

    Wu, Zheng; Schimmele, Christoph M.

    2005-01-01

    Using data from the 1995 General Social Survey (N= 2,639), this study examines two competing repartnering choices made by Canadians after first union disruption: marriage or cohabitation. About 42% of women and 54% of men form a second union 5 years after union disruption, with cohabitation being the most prevalent choice. The timing of second…

  13. The Laboratory Diagnosis of Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Deborah Money

    2005-01-01

    Full Text Available Bacterial vaginosis (BV is an extremely common health problem for women. In addition to the troublesome symptoms often associated with a disruption in the balance of vaginal flora, BV is associated with adverse gynecological and pregnancy outcomes. Although not technically a sexually transmitted infection, BV is a sexually associated condition. Diagnostic tests include real-time clinical/microbiological diagnosis, and the current gold standard, the standardized evaluation of morphotypes on Gram stain analysis. The inappropriate use of vaginal culture can be misleading. Future developments into molecular-based diagnostics will be important to further understand this complex endogenous flora disruption.

  14. Disrupting Ethnography through Rhizoanalysis

    Directory of Open Access Journals (Sweden)

    Diana Masny

    2014-10-01

    Full Text Available This article interrogates principles of ethnography in education proposed by Mills and Morton: raw tellings, analytic pattern, vignette and empathy. This article adopts a position that is uncomfortable, unconventional and interesting. It involves a deterritorialization/ rupture of ethnography in education in order to reterritorialize a different concept: rhizoanalysis, a way to position theory and data that is multilayered, complex and messy. Rhizoanalysis, the main focus of this article is not a method. It is an approach to research conditioned by a reality in which Deleuze and Guattari disrupt representation, interpretation and subjectivity. In this article, Multiple Literacies Theory, a theoretical and practical framework, becomes a lens to examine a rhizomatic study of a Korean family recently arrived to Australia and attending English as a second language classes. Observations and interviews recorded the daily lives of the family. The vignettes were selected by reading data intensively and immanently through a process of palpation, an innovative approach to educational research. Rhizoanalysis proposes to abandon the given and invent different ways of thinking about and doing research and what might happen when reading data differently, intensively and immanently, through Multiple Literacies Theory. Rhizoanalysis, a game-changer in the way research can be conducted, affords a different lens to tackle issues in education through research.

  15. Bacterial ortholog of mammalian translocator protein (TSPO with virulence regulating activity.

    Directory of Open Access Journals (Sweden)

    Annelise Chapalain

    Full Text Available The translocator protein (TSPO, previously designated as peripheral-type benzodiazepine receptor, is a protein mainly located in the outer mitochondrial membrane of eukaryotic cells. TSPO is implicated in major physiological functions and functionally associated with other proteins such as the voltage-dependent anionic channel, also designated as mitochondrial porin. Surprisingly, a TSPO-related protein was identified in the photosynthetic bacterium Rhodobacter sphaeroides but it was initially considered as a relict of evolution. In the present study we cloned a tspO gene in Pseudomonas fluorescens MF37, a non-photosynthetic eubacterium and we used bioinformatics tools to identify TSPO in the genome of 97 other bacteria. P. fluorescens TSPO was recognized by antibodies against mouse protein and by PK 11195, an artificial ligand of mitochondrial TSPO. As in eukaryotes, bacterial TSPO appears functionally organized as a dimer and the apparent Kd for PK 11195 is in the same range than for its eukaryotic counterpart. When P. fluorescens MF37 was treated with PK 11195 (10(-5 M adhesion to living or artificial surfaces and biofilm formation activity were increased. Conversely, the apoptotic potential of bacteria on eukaryotic cells was significantly reduced. This effect of PK11195 was abolished in a mutant of P. fluorescens MF37 deficient for its major outer membrane porin, OprF. The present results demonstrate the existence of a bacterial TSPO that shares common structural and functional characteristics with its mammalian counterpart. This protein, apparently involved in adhesion and virulence, reveals the existence of a possible new inter kingdom signalling system and suggests that the human microbiome should be involuntarily exposed to the evolutionary pressure of benzodiazepines and related molecules. This discovery also represents a promising opportunity for the development of alternative antibacterial strategies.

  16. Bacterial Hydrodynamics

    Science.gov (United States)

    Lauga, Eric

    2016-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells, yet they represent the bulk of the world's biomass and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micrometer scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically complex environments. Using hydrodynamics as an organizing framework, I review the biomechanics of bacterial motility and look ahead to future challenges.

  17. Bacterial hydrodynamics

    CERN Document Server

    Lauga, Eric

    2015-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells yet they represent the bulk of the world's biomass, and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds-number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micron scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically-complex environments. Using hydrodynamics as an organizing framework, we review the biomechanics of bacterial motility and look ahead to future challenges.

  18. Tidal disruption event demographics

    Science.gov (United States)

    Kochanek, C. S.

    2016-09-01

    We survey the properties of stars destroyed in tidal disruption events (TDEs) as a function of black hole (BH) mass, stellar mass and evolutionary state, star formation history and redshift. For M_{BH} ≲ 10^7 M_{⊙}, the typical TDE is due to a M* ˜ 0.3 M⊙ M-dwarf, although the mass function is relatively flat for M_{ast } ≲ M_{⊙}. The contribution from older main-sequence stars and sub-giants is small but not negligible. From MBH ≃ 107.5-108.5 M⊙, the balance rapidly shifts to higher mass stars and a larger contribution from evolved stars, and is ultimately dominated by evolved stars at higher BH masses. The star formation history has little effect until the rates are dominated by evolved stars. TDE rates should decline very rapidly towards higher redshifts. The volumetric rate of TDEs is very high because the BH mass function diverges for low masses. However, any emission mechanism which is largely Eddington-limited for low BH masses suppresses this divergence in any observed sample and leads to TDE samples dominated by MBH ≃ 106.0-107.5 M⊙ BHs with roughly Eddington peak accretion rates. The typical fall-back time is relatively long, with 16 per cent having tfb plausible if tfb has any relation to the transient rise time. For almost any BH mass function, systematic searches for fainter, faster time-scale TDEs in smaller galaxies, and longer time-scale TDEs in more massive galaxies are likely to be rewarded.

  19. When Disruptive Approaches Meet Disruptive Technologies: Learning at a Distance.

    Science.gov (United States)

    Gibson, Chere Campbell

    2000-01-01

    Reviews research on constructivism in learning and selection of learning strategies. Suggests linking constructivism with instructional technologies for continuing medical education in order to "disrupt" reactive, habitual ways of learning and encourage active engagement. (SK)

  20. Endocrine Effects of Circadian Disruption.

    Science.gov (United States)

    Bedrosian, Tracy A; Fonken, Laura K; Nelson, Randy J

    2016-01-01

    Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. PMID:26208951

  1. Neurotoxicity of Thyroid Disrupting Contaminants

    Science.gov (United States)

    Thyroid hormones playa critical role in the normal development ofthe mammalian brain. Thyroid disrupting chemicals (TDCs) are environmental contaminants that alter the structure or function ofthe thyroid gland, alter regulatory enzymes associated with thyroid hormone (TH) homeost...

  2. Vortex disruption by magnetohydrodynamic feedback

    CERN Document Server

    Mak, Julian; Hughes, D W

    2016-01-01

    In an electrically conducting fluid, vortices stretch out a weak, large-scale magnetic field to form strong current sheets on their edges. Associated with these current sheets are magnetic stresses, which are subsequently released through reconnection, leading to vortex disruption, and possibly even destruction. This disruption phenomenon is investigated here in the context of two-dimensional, homogeneous, incompressible magnetohydrodynamics. We derive a simple order of magnitude estimate for the magnetic stresses --- and thus the degree of disruption --- that depends on the strength of the background magnetic field (measured by the parameter $M$, a ratio between the Alfv\\'en speed and a typical flow speed) and on the magnetic diffusivity (measured by the magnetic Reynolds number $\\mbox{Rm}$). The resulting estimate suggests that significant disruption occurs when $M^{2}\\mbox{Rm} = O(1)$. To test our prediction, we analyse direct numerical simulations of vortices generated by the breakup of unstable shear flo...

  3. Carbapenem and cefoxitin resistance of Klebsiella pneumoniae strains associated with porin OmpK36 loss and DHA-1 β-lactamase production

    Directory of Open Access Journals (Sweden)

    Weifeng Shi

    2013-01-01

    Full Text Available Clinical isolates of carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae strains are being increased worldwide. Five pan-resistant K. pneumoniae strains have been isolated from respiratory and ICU wards in a Chinese hospital, and reveal strong resistance to all β-lactams, fluoroquinolones and aminoglycosides. Totally 27 β-lactamase genes and 2 membrane pore protein (porin genes in 5 K. pneumoniae strains were screened by polymerase chain reaction (PCR. The results indicated that all of 5 K. pneumoniae strains carried blaTEM-1 and blaDHA-1 genes, as well as base deletion and mutation of OmpK35 or OmpK36 genes. Compared with carbapenem-sensitive isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, the resistant isolates markedly lacked the protein band of 34-40 kDa, which might be the outer membrane proteins of OmpK36 according to the electrophoresis mobility. In addition, the conjugation test was confirmed that blaDHA-1 mediated by plasmids could be transferred between resistant and sensitive strains. When reserpine (30 µg/mL and carbonyl cyanide m-chlorophenylhydrazone (CCCP (50 µg/mL were added in imipenem and meropenem, the MICs had no change against K. pneumoniae strains. These results suggest that both DHA-1 β-lactamase and loss or deficiency of porin OmpK36 may be the main reason for the cefoxitin and carbapenem resistance in K. pneumoniae strains in our hospital.

  4. Disruptive event analysis: volcanism and igneous intrusion

    International Nuclear Information System (INIS)

    Three basic topics are addressed for the disruptive event analysis: first, the range of disruptive consequences of a radioactive waste repository by volcanic activity; second, the possible reduction of the risk of disruption by volcanic activity through selective siting of a repository; and third, the quantification of the probability of repository disruption by volcanic activity

  5. An enhancer peptide for membrane-disrupting antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Zhang Hong

    2010-02-01

    Full Text Available Abstract Background NP4P is a synthetic peptide derived from a natural, non-antimicrobial peptide fragment (pro-region of nematode cecropin P4 by substitution of all acidic amino acid residues with amides (i.e., Glu → Gln, and Asp → Asn. Results In the presence of NP4P, some membrane-disrupting antimicrobial peptides (ASABF-α, polymyxin B, and nisin killed microbes at lower concentration (e.g., 10 times lower minimum bactericidal concentration for ASABF-α against Staphylococcus aureus, whereas NP4P itself was not bactericidal and did not interfere with bacterial growth at ≤ 300 μg/mL. In contrast, the activities of antimicrobial agents with a distinct mode of action (indolicidin, ampicillin, kanamycin, and enrofloxacin were unaffected. Although the membrane-disrupting activity of NP4P was slight or undetectable, ASABF-α permeabilized S. aureus membranes with enhanced efficacy in the presence of NP4P. Conclusions NP4P selectively enhanced the bactericidal activities of membrane-disrupting antimicrobial peptides by increasing the efficacy of membrane disruption against the cytoplasmic membrane.

  6. TAD disruption as oncogenic driver.

    Science.gov (United States)

    Valton, Anne-Laure; Dekker, Job

    2016-02-01

    Topologically Associating Domains (TADs) are conserved during evolution and play roles in guiding and constraining long-range regulation of gene expression. Disruption of TAD boundaries results in aberrant gene expression by exposing genes to inappropriate regulatory elements. Recent studies have shown that TAD disruption is often found in cancer cells and contributes to oncogenesis through two mechanisms. One mechanism locally disrupts domains by deleting or mutating a TAD boundary leading to fusion of the two adjacent TADs. The other mechanism involves genomic rearrangements that break up TADs and creates new ones without directly affecting TAD boundaries. Understanding the mechanisms by which TADs form and control long-range chromatin interactions will therefore not only provide insights into the mechanism of gene regulation in general, but will also reveal how genomic rearrangements and mutations in cancer genomes can lead to misregulation of oncogenes and tumor suppressors. PMID:27111891

  7. Disruption of gut homeostasis by opioids accelerates HIV disease progression

    Directory of Open Access Journals (Sweden)

    Jingjing eMeng

    2015-06-01

    Full Text Available Cumulative studies during the past 30 years have established the correlation between opioid abuse and human immunodeficiency virus (HIV infection. Further studies also demonstrate that opioid addiction is associated with faster progression to AIDS in patients. Recently, it was revealed that disruption of gut homeostasis and subsequent microbial translocation play important roles in pathological activation of the immune system during HIV infection and contributes to accelerated disease progression. Similarly, opioids have been shown to modulate gut immunity and induce gut bacterial translocation. This review will explore the mechanisms by which opioids accelerate HIV disease progression by disrupting gut homeostasis. Better understanding of these mechanisms will facilitate the search for new therapeutic interventions to treat HIV infection especially in opioid abusing population.

  8. Disruptive Innovation in Healthcare & Rehabilitation

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2014-01-01

    will pay. Disruptive Innovation in context of the author’s body of work in healthcare and rehabilitation relates to how development of a cloud-based converged infrastructure resource, similar to that conceived in a national (Danish) study titled Humanics, can act as an accessible data and knowledge...

  9. Strategies for cryo-electron tomography of the mycobacterial cell envelope and its pore proteins and functional studies of porin MspA from Mycobacterium smegmatis

    OpenAIRE

    Hoffmann, Christian

    2010-01-01

    Cryo-electron tomography (CET) combined with 3D image classification and averaging becomes an increasingly powerful method aiming at the analysis of the structure and interactions of macromolecular complexes in their natural context. By means of the porin MspA from Mycobacterium smegmatis this thesis evaluates to what extent cryopreparation, adapted data acquisition and further developed data analysis and reconstruction can be applied to the in situ analysis of medium sized membrane proteins....

  10. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach that ...

  11. Disrupting the habit of interviewing

    Directory of Open Access Journals (Sweden)

    Eileen Honan

    2014-06-01

    Full Text Available This paper contributes to the growing domain of ‘post-qualitative’ research and experiments with a new (representational form to move away from traditional and clichéd descriptions of research methods. In this paper, I want to interrogate the category of interview, and the habit of interviewing, to disrupt the clichés, so as to allow thinking of different ways of writing/speaking/representing the interactions between researcher and researched that will breathe new life into qualitative inquiries. I will attempt to flatten and shred, destabilise and disrupt our common-sense ideas about interview, including those held most sacred to the qualitative community, that of anonymity and confidentiality, as well as the privilege of the ‘transcript’ in re-presenting interview data.

  12. Optimal Disruption of Complex Networks

    CERN Document Server

    Zhao, Jin-Hua

    2016-01-01

    The collection of all the strongly connected components in a directed graph, among each cluster of which any node has a path to another node, is a typical example of the intertwining structure and dynamics in complex networks, as its relative size indicates network cohesion and it also composes of all the feedback cycles in the network. Here we consider finding an optimal strategy with minimal effort in removal arcs (for example, deactivation of directed interactions) to fragment all the strongly connected components into tree structure with no effect from feedback mechanism. We map the optimal network disruption problem to the minimal feedback arc set problem, a non-deterministically polynomial hard combinatorial optimization problem in graph theory. We solve the problem with statistical physical methods from spin glass theory, resulting in a simple numerical method to extract sub-optimal disruption arc sets with significantly better results than a local heuristic method and a simulated annealing method both...

  13. Disruptive technologies in higher education

    Directory of Open Access Journals (Sweden)

    Michael Flavin

    2012-08-01

    Full Text Available This paper analyses the role of “disruptive” innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs being more or less universal, but these technologies have not been universally adopted and used by students and staff. Instead, other technologies not owned or controlled by HEIs are widely used to support learning and teaching. According to Christensen's theory of Disruptive Innovation, these disruptive technologies are not designed explicitly to support learning and teaching in higher education, but have educational potential. This study uses Activity Theory and Expansive Learning to analyse data regarding the impact of disruptive technologies. The data were obtained through a questionnaire survey about awareness and use of technologies, and through observation and interviews, exploring participants’ actual practice. The survey answers tended to endorse Disruptive Innovation theory, with participants establishing meanings for technologies through their use of them, rather than in keeping with a designer's intentions. Observation revealed that learners use a narrow range of technologies to support learning, but with a tendency to use resources other than those supplied by their HEIs. Interviews showed that participants use simple and convenient technologies to support their learning and teaching. This study identifies a contradiction between learning technologies made available by HEIs, and technologies used in practice. There is no evidence to suggest that a wide range of technologies is being used to support learning and teaching. Instead, a small range of technologies is being used for a wide range of tasks. Students and lecturers are not dependent on their HEIs to support learning and teaching. Instead, they self-select technologies, with use weighted towards established brands. The

  14. HOW TO IDENTIFY DISRUPTIVE NEW BUSINESSES

    OpenAIRE

    Elizabeth Robles

    2015-01-01

    In almost any industry, the most dramatic stories of growth and success were launched from a platform of disruptive innovation (Christensen et al., 2002). The probability of creating a successful, new growth business is 10 times greater if the innovators pursue a disruptive strategy rather than a sustaining one. Genuinely disruptive innovations are the ones that result in the creation of entirely new markets and business models. Few companies have introduced these innovations. Disruptive inno...

  15. Thyroid effects of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Boas, Malene; Feldt-Rasmussen, Ulla; Main, Katharina M

    2012-01-01

    In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert...... thyroid-disrupting effects, and there is emerging evidence that also phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals may have thyroid disrupting properties....

  16. Turbulence and disruptions in Tokamaks

    International Nuclear Information System (INIS)

    In the first part of this thesis, the possible explanation of the electron abnormal thermal conductivity with electromagnetic drift modes rather than simply electrostatic is discussed. A variational form is established in non collisional conditions; linear modes principal possibilities are reviewed, then quasilinear theory is used to calculate the transport phenomenon associated to each mode. They are compared to experimental results. Electron abnormal thermal conductibility is not better explained by electromagnetic modes than by electrostatic modes. In the second part, disruptions are examined; experimental manifestations are briefly recalled. Existing interpretations of these phenomenons are reviewed, which are based on magnetic islands non-linear evolution. A detailed analytical study of the case l=1, m=1 is made. Other disruptions are studied; it is shown that the disruptive process is indissociable from sudden apparition of small scale magnetic turbulence. The possibility of such a turbulence is studied. Its predictable effects are compared to experiment. Such a turbulence, is assumed to exist permanently in an attenuated form, which could justify the electronic transport anomalies in quiescent state

  17. Engineering analysis of TFTR disruption

    Energy Technology Data Exchange (ETDEWEB)

    Murray, J.G.; Rothe, K.E.; Bronner, G.

    1984-09-01

    This report covers an engineering approach quantifying the currents, forces, and times, as well as plasma position, for the worst-case disruption based on engineerign circuit assumptions for the plasma. As the plasma moves toward the wall during the current-decay phase of disruption, the wall currents affect the rate of movement and, hence, the decay time. The calculated structure-induced currents differ considerably from those calculated using a presently available criterion, which specifies that the plasma remains stationary in the center of the torus while decaying in 10 ms. This report outlines the method and basis for the engineering calculation used to determine the current and forces as a function of the circuit characteristics. It provides specific calculations for the Tokamak Fusion Test Reactor (TFTR) with variations in parameters such as the thermal decay time, the torus resistance, and plasma temperature during the current decay. The study reviews possible ways to reduce the disruption damage of TFTR by reducing the magnitude of the plasma external field energy that is absorbed by the plasma during the current decay.

  18. Pharmacological disruption of maladaptive memory.

    Science.gov (United States)

    Taylor, Jane R; Torregrossa, Mary M

    2015-01-01

    Many psychiatric disorders are characterized by intrusive, distracting, and disturbing memories that either perpetuate the illness or hinder successful treatment. For example, posttraumatic stress disorder (PTSD) involves such strong reemergence of memories associated with a traumatic event that the individual feels like the event is happening again. Furthermore, drug addiction is characterized by compulsive use and repeated relapse that is often driven by internal memories of drug use and/or by exposure to external stimuli that were associated with drug use. Therefore, identifying pharmacological methods to weaken the strength of maladaptive memories is a major goal of research efforts aimed at finding new treatments for these disorders. The primary mechanism by which memories could be pharmacologically disrupted or altered is through manipulation of memory reconsolidation. Reconsolidation occurs when an established memory is remembered or reactivated, reentering a labile state before again being consolidated into long-term memory storage. Memories are subject to disruption during this labile state. In this chapter we will discuss the preclinical and clinical studies identifying potential pharmacological methods for disrupting the integrity of maladaptive memory to treat mental illness. PMID:25977090

  19. The disruptive instability in Tokamak plasmas

    NARCIS (Netherlands)

    Salzedas, F.J.B.

    2001-01-01

    Studies performed in RTP (Rijnhuizen Tokamak Project) of the most violent and dangerous instability in tokamak plasmas, the major disruption, are presented. A particular class of disruptions is analyzed, namely the density limit disruption, which occur in high density plasmas. The radiative te

  20. Disruptive innovation as an entrepreneurial process

    NARCIS (Netherlands)

    Y. Chandra; S.-J.S. Yang

    2008-01-01

    Research on conditions and causal mechanisms that influence disruptive innovation has been relatively unexplored in the extant research in disruptive innovation. By re-conceptualizing disruptive innovation as an entrepreneurial process at product, firm and industry levels, this paper draws on emergi

  1. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  2. Disruptive Innovation in Numerical Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Waltz, Jacob I. [Los Alamos National Laboratory

    2012-09-06

    We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.

  3. Disruptive innovation for social change.

    Science.gov (United States)

    Christensen, Clayton M; Baumann, Heiner; Ruggles, Rudy; Sadtler, Thomas M

    2006-12-01

    Countries, organizations, and individuals around the globe spend aggressively to solve social problems, but these efforts often fail to deliver. Misdirected investment is the primary reason for that failure. Most of the money earmarked for social initiatives goes to organizations that are structured to support specific groups of recipients, often with sophisticated solutions. Such organizations rarely reach the broader populations that could be served by simpler alternatives. There is, however, an effective way to get to those underserved populations. The authors call it "catalytic innovation." Based on Clayton Christensen's disruptive-innovation model, catalytic innovations challenge organizational incumbents by offering simpler, good-enough solutions aimed at underserved groups. Unlike disruptive innovations, though, catalytic innovations are focused on creating social change. Catalytic innovators are defined by five distinct qualities. First, they create social change through scaling and replication. Second, they meet a need that is either overserved (that is, the existing solution is more complex than necessary for many people) or not served at all. Third, the products and services they offer are simpler and cheaper than alternatives, but recipients view them as good enough. Fourth, they bring in resources in ways that initially seem unattractive to incumbents. And fifth, they are often ignored, put down, or even encouraged by existing organizations, which don't see the catalytic innovators' solutions as viable. As the authors show through examples in health care, education, and economic development, both nonprofit and for-profit groups are finding ways to create catalytic innovation that drives social change.

  4. Current concepts in neuroendocrine disruption.

    Science.gov (United States)

    León-Olea, Martha; Martyniuk, Christopher J; Orlando, Edward F; Ottinger, Mary Ann; Rosenfeld, Cheryl S; Wolstenholme, Jennifer T; Trudeau, Vance L

    2014-07-01

    In the last few years, it has become clear that a wide variety of environmental contaminants have specific effects on neuroendocrine systems in fish, amphibians, birds and mammals. While it is beyond the scope of this review to provide a comprehensive examination of all of these neuroendocrine disruptors, we will focus on select representative examples. Organochlorine pesticides bioaccumulate in neuroendocrine areas of the brain that directly regulate GnRH neurons, thereby altering the expression of genes downstream of GnRH signaling. Organochlorine pesticides can also agonize or antagonize hormone receptors, adversely affecting crosstalk between neurotransmitter systems. The impacts of polychlorinated biphenyls are varied and in many cases subtle. This is particularly true for neuroedocrine and behavioral effects of exposure. These effects impact sexual differentiation of the hypothalamic-pituitary-gonadal axis, and other neuroendocrine systems regulating the thyroid, metabolic, and stress axes and their physiological responses. Weakly estrogenic and anti-androgenic pollutants such as bisphenol A, phthalates, phytochemicals, and the fungicide vinclozolin can lead to severe and widespread neuroendocrine disruptions in discrete brain regions, including the hippocampus, amygdala, and hypothalamus, resulting in behavioral changes in a wide range of species. Behavioral features that have been shown to be affected by one or more these chemicals include cognitive deficits, heightened anxiety or anxiety-like, sociosexual, locomotor, and appetitive behaviors. Neuroactive pharmaceuticals are now widely detected in aquatic environments and water supplies through the release of wastewater treatment plant effluents. The antidepressant fluoxetine is one such pharmaceutical neuroendocrine disruptor. Fluoxetine is a selective serotonin reuptake inhibitor that can affect multiple neuroendocrine pathways and behavioral circuits, including disruptive effects on reproduction and

  5. Bacillus cereus Certhrax ADP-ribosylates vinculin to disrupt focal adhesion complexes and cell adhesion.

    Science.gov (United States)

    Simon, Nathan C; Barbieri, Joseph T

    2014-04-11

    Bacillus cereus is often associated with mild to moderate gastroenteritis; however, some recent isolates cause inhalational anthrax-like diseases and death. These potential emerging human pathogens express multiple virulence factors. B. cereus strain G9241 expresses anthrax toxin, several polysaccharide capsules, and the novel ADP-ribosyltransferase, Certhrax. In this study, we show that Certhrax ADP-ribosylates Arg-433 of vinculin, a protein that coordinates actin cytoskeleton and extracellular matrix interactions. ADP-ribosylation of vinculin disrupted focal adhesion complexes and redistributed vinculin to the cytoplasm. Exogenous vinculin rescued these phenotypes. This provides a mechanism for strain G9241 to breach host barrier defenses and promote bacterial growth and spread. Certhrax is the first bacterial toxin to add a post-translational modification to vinculin to disrupt the actin cytoskeleton.

  6. Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales.

    Science.gov (United States)

    Zaneveld, Jesse R; Burkepile, Deron E; Shantz, Andrew A; Pritchard, Catharine E; McMinds, Ryan; Payet, Jérôme P; Welsh, Rory; Correa, Adrienne M S; Lemoine, Nathan P; Rosales, Stephanie; Fuchs, Corinne; Maynard, Jeffrey A; Thurber, Rebecca Vega

    2016-01-01

    Losses of corals worldwide emphasize the need to understand what drives reef decline. Stressors such as overfishing and nutrient pollution may reduce resilience of coral reefs by increasing coral-algal competition and reducing coral recruitment, growth and survivorship. Such effects may themselves develop via several mechanisms, including disruption of coral microbiomes. Here we report the results of a 3-year field experiment simulating overfishing and nutrient pollution. These stressors increase turf and macroalgal cover, destabilizing microbiomes, elevating putative pathogen loads, increasing disease more than twofold and increasing mortality up to eightfold. Above-average temperatures exacerbate these effects, further disrupting microbiomes of unhealthy corals and concentrating 80% of mortality in the warmest seasons. Surprisingly, nutrients also increase bacterial opportunism and mortality in corals bitten by parrotfish, turning normal trophic interactions deadly for corals. Thus, overfishing and nutrient pollution impact reefs down to microbial scales, killing corals by sensitizing them to predation, above-average temperatures and bacterial opportunism.

  7. Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales.

    Science.gov (United States)

    Zaneveld, Jesse R; Burkepile, Deron E; Shantz, Andrew A; Pritchard, Catharine E; McMinds, Ryan; Payet, Jérôme P; Welsh, Rory; Correa, Adrienne M S; Lemoine, Nathan P; Rosales, Stephanie; Fuchs, Corinne; Maynard, Jeffrey A; Thurber, Rebecca Vega

    2016-01-01

    Losses of corals worldwide emphasize the need to understand what drives reef decline. Stressors such as overfishing and nutrient pollution may reduce resilience of coral reefs by increasing coral-algal competition and reducing coral recruitment, growth and survivorship. Such effects may themselves develop via several mechanisms, including disruption of coral microbiomes. Here we report the results of a 3-year field experiment simulating overfishing and nutrient pollution. These stressors increase turf and macroalgal cover, destabilizing microbiomes, elevating putative pathogen loads, increasing disease more than twofold and increasing mortality up to eightfold. Above-average temperatures exacerbate these effects, further disrupting microbiomes of unhealthy corals and concentrating 80% of mortality in the warmest seasons. Surprisingly, nutrients also increase bacterial opportunism and mortality in corals bitten by parrotfish, turning normal trophic interactions deadly for corals. Thus, overfishing and nutrient pollution impact reefs down to microbial scales, killing corals by sensitizing them to predation, above-average temperatures and bacterial opportunism. PMID:27270557

  8. Salmonella Disrupts Host Endocytic Trafficking by SopD2-Mediated Inhibition of Rab7

    Directory of Open Access Journals (Sweden)

    Vanessa M. D’Costa

    2015-09-01

    Full Text Available Intracellular bacterial pathogens of a diverse nature share the ability to evade host immunity by impairing trafficking of endocytic cargo to lysosomes for degradation, a process that is poorly understood. Here, we show that the Salmonella enterica type 3 secreted effector SopD2 mediates this process by binding the host regulatory GTPase Rab7 and inhibiting its nucleotide exchange. Consequently, this limits Rab7 interaction with its dynein- and kinesin-binding effectors RILP and FYCO1 and thereby disrupts host-driven regulation of microtubule motors. Our study identifies a bacterial effector capable of directly binding and thereby modulating Rab7 activity and a mechanism of endocytic trafficking disruption that may provide insight into the pathogenesis of other bacteria. Additionally, we provide a powerful tool for the study of Rab7 function, and a potential therapeutic target.

  9. Multistage Logistic Network Optimization under Disruption Risk

    OpenAIRE

    Rusman, Muhammad

    2013-01-01

    Getting over disruptions risk has been a challenging issue for many companies under the globalization that will link to potential external source such as demand uncertainties, natural disasters, and terrorist attacks. The disruption is an unexpected event that disturbs normal flows of products and materials within a supply chain. The disruption at one members of supply chain will propagate the offers and finally affect significant impacts on the entire chain. If we look back...

  10. Disrupted Sleep: From Molecules to Cognition

    OpenAIRE

    Someren, E.J.W.; Cirelli, C.; Dijk, D.-J.; Van Cauter, E; Schwartz, Sophie; Chee, M. W. L.

    2015-01-01

    Although the functions of sleep remain to be fully elucidated, it is clear that there are far-reaching effects of its disruption, whether by curtailment for a single night, by a few hours each night over a long period, or by disruption in sleep continuity. Epidemiological and experimental studies of these different forms of sleep disruption show deranged physiology from subcellular levels to complex affective behavior. In keeping with the multifaceted influence of sleep on health and well-bei...

  11. Disrupted Sleep: From Molecules to Cognition

    OpenAIRE

    Van Someren, Eus J. W.; Cirelli, Chiara; Dijk, Derk-Jan; Van Cauter, Eve; Schwartz, Sophie; Chee, Michael W. L.

    2015-01-01

    UNLABELLED: Although the functions of sleep remain to be fully elucidated, it is clear that there are far-reaching effects of its disruption, whether by curtailment for a single night, by a few hours each night over a long period, or by disruption in sleep continuity. Epidemiological and experimental studies of these different forms of sleep disruption show deranged physiology from subcellular levels to complex affective behavior. In keeping with the multifaceted influence of sleep on health ...

  12. Disruption management in passenger railway transportation.

    OpenAIRE

    Jespersen-Groth, J.; Potthoff, Daniel; Clausen, J.; Huisman, Dennis; Kroon, Leo; Maróti, Gábor; Nielsen, M.N.

    2007-01-01

    textabstractThis paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss the three main subproblems in railway disruption management: timetable adjustment, and rolling stock and crew re-scheduling. Next to a general description of these problems, we give an o...

  13. Towards a Framework of Digital Platform Disruption

    OpenAIRE

    Kazan, Erol; Tan, Chee-Wee; Lim, Eric T. K.

    2014-01-01

    Digital platforms are disruptive information technology (IT) artifacts that erode conventional business logic associated with traditional market structures. This paper presents a framework for examining the disruptive potential of digital platforms whereby we postulate that the strategic interplay of governance regimes and platform layers is deterministic of whether disruptive derivatives are permitted to flourish. This framework has been employed in a comparative case study betwe...

  14. Catastrophic disruption experiments: Recent results

    Science.gov (United States)

    Martelli, G.; Ryan, E. V.; Nakamura, A. M.; Giblin, I.

    1994-01-01

    This paper presents a review of the progress in the field of catastrophic disruption experiments over the past 4 years, since the publication of the review paper by Fujiwara et al. (1989). We describe the development of new techniques to produce shattering impacts relevant to the study of the collisional evolution of the asteroids, and summarize the results from numerous experiments which have been performed to date, using a variety of materials for both the impactor and the targets. Some of these, such as ice-on-ice, loose aggregates and pressurized targets, are quite new and have provided novel and exciting results. Some of the gaps existing previously in the data on fragment ejection-angle distributions, as well as translational and rotational velocity fields (including fine fragments) have been filled, and these new results will be surveyed.

  15. Disrupting Entanglement of Black Holes

    CERN Document Server

    Leichenauer, Stefan

    2014-01-01

    We study entanglement in thermofield double states of strongly coupled CFTs by analyzing two-sided Reissner-Nordstrom solutions in AdS. The central object of study is the mutual information between a pair of regions, one on each asymptotic boundary of the black hole. For large regions the mutual information is positive and for small ones it vanishes; we compute the critical length scale, which goes to infinity for extremal black holes, of the transition. We also generalize the butterfly effect of Shenker and Stanford to a wide class of charged black holes, showing that mutual information is disrupted upon perturbing the system and waiting for a time of order $\\log E/\\delta E$ in units of the temperature. We conjecture that the parametric form of this timescale is universal.

  16. Vimentin in Bacterial Infections

    Directory of Open Access Journals (Sweden)

    Tim N. Mak

    2016-04-01

    Full Text Available Despite well-studied bacterial strategies to target actin to subvert the host cell cytoskeleton, thus promoting bacterial survival, replication, and dissemination, relatively little is known about the bacterial interaction with other components of the host cell cytoskeleton, including intermediate filaments (IFs. IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge about the role of IFs in bacterial infections, focusing on the type III IF protein vimentin. Recent studies have revealed the involvement of vimentin in host cell defenses, acting as ligand for several pattern recognition receptors of the innate immune system. Two main aspects of bacteria-vimentin interactions are presented in this review: the role of vimentin in pathogen-binding on the cell surface and subsequent bacterial invasion and the interaction of cytosolic vimentin and intracellular pathogens with regards to innate immune signaling. Mechanistic insight is presented involving distinct bacterial virulence factors that target vimentin to subvert its function in order to change the host cell fate in the course of a bacterial infection.

  17. The role of anthrolysin O in gut epithelial barrier disruption during Bacillus anthracis infection.

    Science.gov (United States)

    Bishop, Brian L; Lodolce, James P; Kolodziej, Lauren E; Boone, David L; Tang, Wei Jen

    2010-04-01

    Gastrointestinal (GI) anthrax, caused by the bacterial infection of Bacillus anthracis, posts a significant bioterrorism threat by its relatively high mortality rate in humans. Different from inhalational anthrax by the route of infection, accumulating evidence indicates the bypass of vegetative bacteria across GI epithelium is required to initiate GI anthrax. Previously, we reported that purified anthrolysin O (ALO), instead of tripartite anthrax edema and lethal toxins, is capable of disrupting gut epithelial tight junctions and barrier function in cultured cells. Here, we show that ALO can disrupt intestinal tissue barrier function in an ex vivo mouse model. To explore the effects of ALO in a cell culture model of B. anthracis infection, we showed that anthrax bacteria can effectively reduce the monolayer integrity of human Caco-2 brush-border expressor (C2BBE) cells based on the reduced transepithelial resistance and the increased leakage of fluorescent dye. This disruption is likely caused by tight junction dysfunction observed by the reorganization of the tight junction protein occludin. Consequently, we observe significant passage of vegetative anthrax bacteria across C2BBE cells. This barrier disruption and bacterial crossover requires ALO since ALO-deficient B. anthracis strains fail to induce monolayer dysfunction and allow the passage of anthrax bacteria. Together these findings point to a pivotal role for ALO within the establishment of GI anthrax infection and the initial bypass of the epithelial barrier. PMID:20188700

  18. Ultraviolet irradiation disrupts somatic pili structure and function

    Energy Technology Data Exchange (ETDEWEB)

    Silverblatt, F.J.

    1979-09-01

    Three piliated bacterial species were exposed to ultraviolet light and the effect of increasing duration of irradiation on the integrity of the somatic pili was quantitated by negative-stain electron microscopy. Heavily piliated Proteus mirabilis became devoid of pili after 20 min of irradiation, but Escherichia coli and Neisseria gonorrhoeae required 40 min for complete depiliation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that new, small molecular weight fragments appeared after irradiation of purified E. coli pili, suggesting that cleavage of the peptide chain rather than dissociation of pilin monomers accounted for the loss of pili structure. These observations indicate that the ultrastructural integrity and function of pili can be disrupted by ultraviolet light.

  19. Survey of disruption causes at JET

    NARCIS (Netherlands)

    de Vries, P. C.; Johnson, M. F.; Alper, B.; Buratti, P.; Hender, T. C.; Koslowski, H. R.; Riccardo, V.

    2011-01-01

    A survey has been carried out into the causes of all 2309 disruptions over the last decade of JET operations. The aim of this survey was to obtain a complete picture of all possible disruption causes, in order to devise better strategies to prevent or mitigate their impact. The analysis allows the e

  20. Rurality and Patterns of Social Disruption.

    Science.gov (United States)

    Wilkinson, Kenneth P.

    1984-01-01

    Argues that structural cleavages provoke social disruptions where opportunities are conducive. Thus, combinations of rurality with particular structural cleavages predict specific disruption patterns. Data from northeastern United States indicate that rurality, combined with other population characteristics (provocation, ascriptive inequality,…

  1. Network Formation under the Threat of Disruption

    NARCIS (Netherlands)

    Hoyer, B.

    2013-01-01

    The studies in this thesis are focused on the impact the presence of a network disruptor has on network formation models. In particular, we build two theoretical models to study the effect of network disruption on network formation and test the effect network disruption has on equilibrium selection

  2. Interfering with bacterial gossip

    DEFF Research Database (Denmark)

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

    2011-01-01

    defense. Antibiotics exhibit a rather limited effect on biofilms. Furthermore, antibiotics have an ‘inherent obsolescence’ because they select for development of resistance. Bacterial infections with origin in bacterial biofilms have become a serious threat in developed countries. Pseudomonas aeruginosa...... that appropriately target bacteria in their relevant habitat with the aim of mitigating their destructive impact on patients. In this review we describe molecular mechanisms involved in “bacterial gossip” (more scientifically referred to as quorum sensing (QS) and c-di-GMP signaling), virulence, biofilm formation...

  3. High-level carbapenem-resistant OXA-48-producing Klebsiella pneumoniae with a novel OmpK36 variant and low-level, carbapenem-resistant, non-porin-deficient, OXA-181-producing Escherichia coli from Thailand.

    Science.gov (United States)

    Lunha, Kamonwan; Chanawong, Aroonwadee; Lulitanond, Aroonlug; Wilailuckana, Chotechana; Charoensri, Nicha; Wonglakorn, Lumyai; Saenjamla, Pimjai; Chaimanee, Prajuab; Angkititrakul, Sunpetch; Chetchotisakd, Ploenchan

    2016-06-01

    Five blaOXA-48-like-carrying Enterobacteriaceae isolates collected from two Thai patients in December 2012 were characterized. Three Klebsiella pneumoniae isolates giving two different pulsed-field gel electrophoresis patterns and sequence types (ST11 and ST37) from patient 1 harbored blaOXA-48 locating on Tn1999.2, whereas two Escherichia coli isolates with the same pulsotype and ST5 from Patient 2 carried ISEcp1-associated blaOXA-181. One K. pneumoniae strain had blaSHV-12, blaDHA-1, qnrB, and qnrS, while another strain harbored blaCTX-M-15, qnrS and aac(6')-Ib-cr. The E. coli strain contained blaCTX-M-15, blaCMY-2, qnrS, and aac(6')-Ib-cr. Interestingly, the OXA-48 producers with a novel OmpK36 variant by a substitution of Gly to Asp in the L3 loop-borne PEFXG motif exhibited high-level resistance to ertapenem, imipenem, and meropenem. In contrast, the OXA-181 producer with non-porin-deficient background showed low-level resistance to ertapenem only. Both patients died because of either septic shock or pneumonia. This study showed the impact of OXA-48-like carbapenemases in porin-defective clinical isolate background, which may lead to serious therapeutic problems in the near future. PMID:27041106

  4. Bacterial Wound Culture

    Science.gov (United States)

    ... Home Visit Global Sites Search Help? Bacterial Wound Culture Share this page: Was this page helpful? Also known as: Aerobic Wound Culture; Anaerobic Wound Culture Formal name: Culture, wound Related ...

  5. Bacterial surface adaptation

    Science.gov (United States)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  6. Bacterial intermediate filaments

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Cabeen, M.; Jacobs-Wagner, C.

    2009-01-01

    Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin...

  7. Bacterial Meningitis in Infants

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-04-01

    Full Text Available A retrospective study of 80 infantile patients (ages 30-365 days; 47 male, 33 female with culture-proven bacterial meningitis seen over a 16 year period (1986-2001 is reported from Taiwan.

  8. Erosion products in disruption simulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Safronov, V.; Arkhipov, N.; Bakhtin, V.; Barsuk, V.; Kurkin, S.; Mironova, E.; Toporkov, D.; Vasenin, S.; Zhitlukhin, A. [Troitsk Inst. for Innovation and Fusion Research, Troisk, Moscow region (Russian Federation); Arkhipov, I. [Inst. of Physical Chemistry, Russian Academy of Science, Moscow (Russian Federation); Werle, H.; Wuerz, H. [Forschungszentrum Karlsruhe (Germany)

    1998-07-01

    Erosion of divertor materials under tokamak disruption event presents a serious problem of ITER technology. Erosion restricts the divertor lifetime and leads to production of redeposited layers of the material retaining large amount of tritium, which is a major safety issue for future fusion reactor. Since ITER disruptive heatloads are not achievable in existing tokamaks, material erosion is studied in special simulation experiments. Till now the simulation experiments have focused mainly on investigation of shielding effect and measurement of erosion rate. In the present work the properties of eroded and redeposited graphite are studied under condition typical for hard ITER disruption. (author)

  9. Disruptive School Peers and Student Outcomes

    DEFF Research Database (Denmark)

    Kristoffersen, Jannie H. G.; Krægpøth, Morten Visby; Skyt Nielsen, Helena;

    This paper estimates how peers’ achievement gains are affected by the presence of potentially disruptive and emotionally sensitive children in the school-cohort. We exploit that some children move between schools and thus generate variation in peer composition in the receiving schoolcohort. We...... identify three groups of potentially disruptive and emotionally sensitive children from detailed Danish register data: children with divorced parents, children with parents convicted of crime, and children with a psychiatric diagnosis. We find that adding potentially disruptive children lowers the academic...... achievement of peers by about 1.5-2 percent of a standard deviation....

  10. Disruptive School Peers and Student Outcomes

    DEFF Research Database (Denmark)

    Kristoffersen, Jannie H. Grøne; Krægpøth, Morten; Nielsen, Helena Skyt;

    This paper estimates how peers’ achievement gains are affected by the presence of potentially disruptive and emotionally sensitive children in the school-cohort. We exploit that some children move between schools and thus generate variation in peer composition in the receiving school-cohort. We...... identify three groups of potentially disruptive and emotionally sensitive children from detailed Danish register data: children with divorced parents, children with parents convicted of crime, and children with a psychiatric diagnosis. We find that adding potentially disruptive children lowers the academic...... achievement of peers by about 1.7-2.3 percent of a standard deviation....

  11. Disruptive School Peers and Student Outcomes

    DEFF Research Database (Denmark)

    Kristoffersen, Jannie H. G.; Krægpøth, Morten; Nielsen, Helena Skyt;

    2015-01-01

    This paper estimates how peers’ achievement gains are affected by the presence of potentially disruptive and emotionally sensitive children in the school-cohort. We exploit that some children move between schools and thus generate variation in peer composition in the receiving school-cohort. We...... identify three groups of potentially disruptive and emotionally sensitive children from detailed Danish register data: children with divorced parents, children with parents convicted of crime, and children with a psychiatric diagnosis. We find that adding potentially disruptive children lowers the academic...... achievement of peers by about 1.7–2.3% of a standard deviation....

  12. OF SYSTEMS THAT HAVE DISRUPTABLE CONSTRAINS

    Directory of Open Access Journals (Sweden)

    Chernov Yuriy Tikhonovich

    2012-07-01

    Formulas of equivalent static loads, with the help of which the systems are analyzed when constraints are disrupted, are generated. No inertial force is to be derived to obtain equivalent static loads. This is important in view of their application in dynamic analyses . Analysis of the static system in the event of disrupted constraints is based on the equations derived by the authors. The result of the analysis represents an inverse linear relation of static loading and relative stiffness of the system with disrupted constraints. This means that the lower the stiffness of the system, the higher the static loading.

  13. Disruption Management in Passenger Railway Transportation

    DEFF Research Database (Denmark)

    Groth, Julie Jespersen; Potthoff, Daniel; Clausen, Jens;

    2009-01-01

    This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss...... the three main subproblems in railway disruption management: timetable adjustment, and rolling stock and crew re-scheduling. Next to a general description of these problems, we give an overview of the existing literature and we present some details of the specific situations at DSB S-tog and NS...

  14. DISRUPTIVE BEHAVIOUR AMONGST DOCTORS, MYTH OR REALITY?

    Directory of Open Access Journals (Sweden)

    Avtar Singh

    2014-01-01

    Full Text Available BACKGROUND : Disruptive behavior in a medical setting is defined as objectionable or offensive interpersonal behavior that leads to disruption of professional activities in the workplace. 1 It has been observed that majority of doctors do not show disruptive behavior in their day today conduct and only few doctors are identified for their disruptive behavior . Special commi ttee on professional conduct and ethics defines disruptive behavior in physicians as aberrant behavior manifested through personal interaction with physicians , hospital personnel , health care professionals , patients , family members or others which interferes with patient care or could reasonably be expected to interfere with the process of delivering quality care. 2 Common forms of disruptive behaviors generally seen amongst young doctors are use of abusive language , yelling or shouting at patients , colleagues and subordinate staff , showing in disciplined behavior and at times indulging in physical abuse. 3 - 4 STUDY DESIGN : Study was conducted at a tertiary care hospital where 614 health care professionals participated which included 108 doctors 432 nurs ing staff and 74 paramedical staff METHOD : Data collection was done by semi structured pretested questionnaire and was entered in Microsoft Excel and analyzed for frequency and percentages . RESULTS : 64 % doctor , 66% nursing staff and 50% of the paramedicals answered that they have seen doctors showing disruptive behavior at one time or the other . Not all the doctors show disruptive behavior but this type of aberrant behavior is seen mainly in2 - 3 percent of doctors only. While answering to the que stion as to the type of disruptive behavior , 57% health care professionals reported that commonest form of disruptive behavior noticed by them amongst doctors was yelling or shouting on junior staff , patients and colleagues . 47% answered that doctors with disruptive behavior do not follow laid down orders or

  15. A Common Fold Mediates Vertebrate Defense and Bacterial Attack

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, Carlos J.; Buckle, Ashley M.; Law, Ruby H.P.; Butcher, Rebecca E.; Kan, Wan-Ting; Bird, Catherina H.; Ung, Kheng; Browne, Kylie A.; Baran, Katherine; Bashtannyk-Puhalovich, Tanya A.; Faux, Noel G.; Wong, Wilson; Porter, Corrine J.; Pike, Robert N.; Ellisdon, Andrew M.; Pearce, Mary C.; Bottomley, Stephen P.; Emsley, Jonas; Smith, A. Ian; Rossjohn, Jamie; Hartland, Elizabeth L.; Voskoboinik, Ilia; Trapani, Joseph A.; Bird, Phillip I.; Dunstone, Michelle A.; Whisstock, James C. (PMCI-A); (Monash); (Nottingham)

    2008-10-02

    Proteins containing membrane attack complex/perforin (MACPF) domains play important roles in vertebrate immunity, embryonic development, and neural-cell migration. In vertebrates, the ninth component of complement and perforin form oligomeric pores that lyse bacteria and kill virus-infected cells, respectively. However, the mechanism of MACPF function is unknown. We determined the crystal structure of a bacterial MACPF protein, Plu-MACPF from Photorhabdus luminescens, to 2.0 angstrom resolution. The MACPF domain reveals structural similarity with poreforming cholesterol-dependent cytolysins (CDCs) from Gram-positive bacteria. This suggests that lytic MACPF proteins may use a CDC-like mechanism to form pores and disrupt cell membranes. Sequence similarity between bacterial and vertebrate MACPF domains suggests that the fold of the CDCs, a family of proteins important for bacterial pathogenesis, is probably used by vertebrates for defense against infection.

  16. Functionalized polyanilines disrupt Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    Science.gov (United States)

    Gizdavic-Nikolaidis, Marija R; Pagnon, Joanne C; Ali, Naseem; Sum, Reuben; Davies, Noel; Roddam, Louise F; Ambrose, Mark

    2015-12-01

    The purpose of the present study was to investigate the antimicrobial effects of functionalized polyanilines (fPANIs) against stationary phase cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus using homopolymer of sulfanilic acid (poly-SO3H) as a model. The chemically synthesized poly-SO3H was characterized using Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopies. The molecular weight (Mw) and elemental analysis of homopolymer poly-SO3H were also examined. We found that poly-SO3H was bactericidal against stationary phase cells of P. aeruginosa and S. aureus at a concentration of 20 mgml(-1). Surprisingly, we discovered that the same concentration (20 mgml(-1)) of poly-SO3H significantly disrupted and killed bacterial cells present in pre-established forty-eight hour static biofilms of these organisms, as shown by crystal violet and bacterial live/dead fluorescence staining assays. In support of these data, poly-SO3H extensively diminished the expression of bacterial genes related to biofilm formation in stationary phase cells of P. aeruginosa, and seemed to greatly reduce the amount of the quorum sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) able to be recovered from biofilms of this organism. Furthermore, we found that poly-SO3H was able to effectively penetrate and kill cells in biofilms formed by the P. aeruginosa (AESIII) isolate derived from the sputum of a cystic fibrosis patient. Taken together, the results of the present study emphasise the broad antimicrobial activities of fPANI, and suggest that they could be developed further and used in some novel ways to construct medical devices and/or industrial equipment that are refractory to colonization by biofilm-forming bacteria.

  17. Functionalized polyanilines disrupt Pseudomonas aeruginosa and Staphylococcus aureus biofilms.

    Science.gov (United States)

    Gizdavic-Nikolaidis, Marija R; Pagnon, Joanne C; Ali, Naseem; Sum, Reuben; Davies, Noel; Roddam, Louise F; Ambrose, Mark

    2015-12-01

    The purpose of the present study was to investigate the antimicrobial effects of functionalized polyanilines (fPANIs) against stationary phase cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus using homopolymer of sulfanilic acid (poly-SO3H) as a model. The chemically synthesized poly-SO3H was characterized using Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopies. The molecular weight (Mw) and elemental analysis of homopolymer poly-SO3H were also examined. We found that poly-SO3H was bactericidal against stationary phase cells of P. aeruginosa and S. aureus at a concentration of 20 mgml(-1). Surprisingly, we discovered that the same concentration (20 mgml(-1)) of poly-SO3H significantly disrupted and killed bacterial cells present in pre-established forty-eight hour static biofilms of these organisms, as shown by crystal violet and bacterial live/dead fluorescence staining assays. In support of these data, poly-SO3H extensively diminished the expression of bacterial genes related to biofilm formation in stationary phase cells of P. aeruginosa, and seemed to greatly reduce the amount of the quorum sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL) able to be recovered from biofilms of this organism. Furthermore, we found that poly-SO3H was able to effectively penetrate and kill cells in biofilms formed by the P. aeruginosa (AESIII) isolate derived from the sputum of a cystic fibrosis patient. Taken together, the results of the present study emphasise the broad antimicrobial activities of fPANI, and suggest that they could be developed further and used in some novel ways to construct medical devices and/or industrial equipment that are refractory to colonization by biofilm-forming bacteria. PMID:26496473

  18. Disruptions, Disruptivity, and Safer Operating Windows in the High-β Spherical Torus NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, S P; Diallo, A; Gates, D; LeBlanc, B P; Menard, J E; Mueller, D; Sabbagh, S A; Soukhanovskii, V; Tritz, K

    2012-09-27

    This paper discusses disruption rates, disruption causes, and disruptivity statistics in the high- βN National Spherical Torus Experiment (NSTX) [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. While the overall disruption rate is rather high, configurations with high βN , moderate q*, strong boundary shaping, sufficient rotation, and broad pressure and current profiles are found to have the lowest disruptivity; active n=1 control further reduces the disruptivity. The disruptivity increases rapidly for q*<2.7, which is substantially above the ideal MHD current limit. In quiescent conditions, qmin >1.25 is generally acceptable for avoiding the onset of core rotating n=1 kink/tearing modes; when EPM and ELM disturbances are present, the required qmin for avoiding those modes is raised to ~1.5. The current ramp and early flat-top phase of the discharges are prone to n=1 core rotating modes locking to the wall, leading to a disruption. Small changes to the discharge fueling during this phase can often mitigate the rotation damping associated with these modes and eliminate the disruption. The largest stored energy disruptions are those that occur at high current when a plasma current rampdown is initiated incorrectly.

  19. Thyroid disrupting chemicals: Mechanisms and mixtures

    Science.gov (United States)

    Environmental contaminants are known to act as thyroid disrupting chemicals (TDCs). Broadly defined, TDCs are xenobiotics that alter the structure or function of the thyroid gland, alter regulatory enzymes associated with thyroid hormone (TH) homeostasis, or change circulating o...

  20. Glaciological parameters of disruptive event analysis

    International Nuclear Information System (INIS)

    The following disruptive events caused by ice sheets are considered: continental glaciation, erosion, loading and subsidence, deep ground water recharge, flood erosion, isostatic rebound rates, melting, and periodicity of ice ages

  1. Double tidal disruptions in galactic nuclei

    CERN Document Server

    Mandel, Ilya

    2015-01-01

    A star on a nearly radial trajectory approaching a massive black hole (MBH) gets tidally disrupted if it comes sufficiently close to the MBH. Here we explore what happens to binary stars whose centers of mass approach the MBH on nearly radial orbits. The interaction with the MBH often leads to both stars being disrupted in sequence. We argue that such events could produce light curves that are substantially different from those of the single disruptions, with possible features such as two local maxima. Tidal forces from the MBH can also lead the binary components to collide; these merger products can form highly magnetized stars, whose subsequent tidal disruption may enable prompt jet formation.

  2. Passive runaway electron suppression in tokamak disruptions

    International Nuclear Information System (INIS)

    Runaway electrons created in disruptions pose a serious problem for tokamaks with large current. It would be desirable to have a runaway electron suppression method which is passive, i.e., a method that does not rely on an uncertain disruption prediction system. One option is to let the large electric field inherent in the disruption drive helical currents in the wall. This would create ergodic regions in the plasma and increase the runaway losses. Whether these regions appear at a suitable time and place to affect the formation of the runaway beam depends on disruption parameters, such as electron temperature and density. We find that it is difficult to ergodize the central plasma before a beam of runaway current has formed. However, the ergodic outer region will make the Ohmic current profile contract, which can lead to instabilities that yield large runaway electron losses

  3. Shell Galaxies, Dynamical Friction, and Dwarf Disruption

    CERN Document Server

    Ebrova, Ivana; Canalizo, Gabriela; Bennert, Nicola; Jilkova, Lucie

    2009-01-01

    Using N-body simulations of shell galaxies created in nearly radial minor mergers, we investigate the error of collision dating, resulting from the neglect of dynamical friction and of gradual disruption of the cannibalized dwarf.

  4. Towards a Framework of Digital Platform Disruption

    DEFF Research Database (Denmark)

    Kazan, Erol; Tan, Chee-Wee; Lim, Eric T. K.

    2014-01-01

    Digital platforms are disruptive information technology (IT) artifacts that erode conventional business logic associated with traditional market structures. This paper presents a framework for examining the disruptive potential of digital platforms whereby we postulate that the strategic interplay...... of governance regimes and platform layers is deterministic of whether disruptive derivatives are permitted to flourish. This framework has been employed in a comparative case study between centralized (i.e., PayPal) and decentralized (i.e., Coinkite) digital payment platforms to illustrate its applicability...... and yield propositions on the nature and impact of digital platform disruptions. Preliminary findings indicate that centralized digital platforms attempt to create unique configurals to obtain monopolistic power by tightly coupling platform layers, which are difficult to replicate. Conversely, decentralized...

  5. Disruptive Innovation in Chinese and Indian Businesses

    DEFF Research Database (Denmark)

    markets, has made these emerging economies fertile ground for developing and applying disruptive innovations. A novel mix of key attributes distinctive from those of established technologies or business models, disruptive innovations are typically inferior, yet affordable and "good-enough" products...... or services, which originate in lower-end market segments, but later move up to compete with those provided by incumbent firms. This book sheds new light on disruptive innovations both from and for the bottom of the pyramid in China and India, from the point of view of local entrepreneurs and international...... firms seeking to operate their businesses there. It covers both the theoretical and practical implications of disruptive innovation using conceptual frameworks alongside detailed case studies, whilst also providing a comparison of conditions and strategic options in India and China. Further, unlike...

  6. Report on Criteria for Endocrine Disrupters

    DEFF Research Database (Denmark)

    Holbech, Henrik

    2011-01-01

    This report has been prepared by the Danish Centre on Endocrine Disrupters as a project contracted by the Danish Environmental Protection Agency. The Danish Centre on Endocrine Disrupters is an interdisciplinary scientific network without walls. The main purpose of the Centre is to build and gather...... new knowledge on endocrine disrupters with the focus on providing information requested for the preventive work of the regulatory authorities. The Centre is financed by the Ministry of the Environment and the scientific work programme is followed by an international scientific advisory board....... The overall aim of this project is to provide a science based proposal for criteria for endocrine disrupters. The terms of reference for the project specify elements to be included and/or addressed when developing the criteria (Annex 1). Also, several international reports and papers dealing with assessment...

  7. 75 FR 30306 - Responding To Disruptive Patients

    Science.gov (United States)

    2010-06-01

    ... performance of official duties by Government employees.'' The sole enforcement mechanism provided by paragraph... opposes the use of punishment in the management of disruptive patients. Instead, it reflects the view...

  8. The bacterial lipocalins.

    Science.gov (United States)

    Bishop, R E

    2000-10-18

    The lipocalins were once regarded as a eukaryotic protein family, but new members have been recently discovered in bacteria. The first bacterial lipocalin (Blc) was identified in Escherichia coli as an outer membrane lipoprotein expressed under conditions of environmental stress. Blc is distinguished from most lipocalins by the absence of intramolecular disulfide bonds, but the presence of a membrane anchor is shared with two of its closest homologues, apolipoprotein D and lazarillo. Several common features of the membrane-anchored lipocalins suggest that each may play an important role in membrane biogenesis and repair. Additionally, Blc proteins are implicated in the dissemination of antibiotic resistance genes and in the activation of immunity. Recent genome sequencing efforts reveal the existence of at least 20 bacterial lipocalins. The lipocalins appear to have originated in Gram-negative bacteria and were probably transferred horizontally to eukaryotes from the endosymbiotic alpha-proteobacterial ancestor of the mitochondrion. The genome sequences also reveal that some bacterial lipocalins exhibit disulfide bonds and alternative modes of subcellular localization, which include targeting to the periplasmic space, the cytoplasmic membrane, and the cytosol. The relationships between bacterial lipocalin structure and function further illuminate the common biochemistry of bacterial and eukaryotic cells.

  9. The Relative Ineffectiveness of Criminal Network Disruption

    OpenAIRE

    Duijn, P.A.C.; Kashirin, V.; Sloot, P.M.A.

    2014-01-01

    Researchers, policymakers and law enforcement agencies across the globe struggle to find effective strategies to control criminal networks. The effectiveness of disruption strategies is known to depend on both network topology and network resilience. However, as these criminal networks operate in secrecy, data-driven knowledge concerning the effectiveness of different criminal network disruption strategies is very limited. By combining computational modeling and social network analysis with u...

  10. Anastomotic disruption after large bowel resection

    Institute of Scientific and Technical Information of China (English)

    Mohammad U NasirKhan; Farshad Abir; Walter Longo; Robert Kozol

    2006-01-01

    Anastomotic disruption is a feared and serious complication of colon surgery. Decades of research have identified factors favoring successful healing of anastomoses as well as risk factors for anastomotic disruption. However, some factors, such as the role of mechanical bowel preparation, remain controversial.Despite proper caution and excellent surgical technique,some anastomotic leaks are inevitable. The rapid identification of anastomotic leaks and the timely treatment in these cases are paramount.

  11. BUSINESS MODEL PATTERNS FOR DISRUPTIVE TECHNOLOGIES

    OpenAIRE

    BENJAMIN AMSHOFF; CHRISTIAN DÜLME; JULIAN ECHTERFELD; JÜRGEN GAUSEMEIER

    2015-01-01

    Companies nowadays face a myriad of business opportunities as a direct consequence of manifold disruptive technology developments. As a basic characteristic, disruptive technologies lead to a severe shift in value-creation networks giving rise to new market segments. One of the key challenges is to anticipate the business logics within these nascent and formerly unknown markets. Business model patterns promise to tackle this challenge. They can be interpreted as proven business model elements...

  12. On asymmetric collisions with large disruption parameters

    International Nuclear Information System (INIS)

    Collisions between a weak electron bunch and a strong positron bunch are studied within a flat model. Electrons are tracked through the transverse space charge field of the positron bunch, and it is shown that positrons in a storage ring may remain stable after asymmetric collisions with a weak electron bunch in spite of large values of the electron disruption parameter. The plasma oscillations that affect collisions with large disruption parameters may be suppressed by properly matching the electrons. 8 refs., 5 figs

  13. Sleep and circadian rhythm disruption in schizophrenia†

    OpenAIRE

    Wulff, Katharina; Dijk, Derk-Jan; Middleton, Benita; Foster, Russell G.; Joyce, Eileen M.

    2012-01-01

    Background Sleep disturbances comparable with insomnia occur in up to 80% of people with schizophrenia, but very little is known about the contribution of circadian coordination to these prevalent disruptions. Aims A systematic exploration of circadian time patterns in individuals with schizophrenia with recurrent sleep disruption. Method We examined the relationship between sleep-wake activity, recorded actigraphically over 6 weeks, along with ambient light exposure and simultaneous circadia...

  14. Airline Disruption Management - Perspectives, Experiences and Outlook

    OpenAIRE

    Kohl, Niklas; Larsen, Allan; Larsen, Jesper; Ross, Alex; Tiourine, Sergey

    2004-01-01

    Over the past decade, airlines have become more concerned with developing an optimal flight schedule, with very little slack left to accommodate for any form of variation from the optimal solution. During operation the planned schedules often have to be revised due to disruptions caused by for example severe weather, technical problems and crew sickness. Thus, the field of Airline Disruption Management has emerged within the past few years. The increased focus on cutting cost at the major air...

  15. Anastomotic disruption after large bowel resection

    OpenAIRE

    NasirKhan, Mohammad U; Abir, Farshad; Longo, Walter; Kozol, Robert

    2006-01-01

    Anastomotic disruption is a feared and serious complication of colon surgery. Decades of research have identified factors favoring successful healing of anastomoses as well as risk factors for anastomotic disruption. However, some factors, such as the role of mechanical bowel preparation, remain controversial. Despite proper caution and excellent surgical technique, some anastomotic leaks are inevitable. The rapid identification of anastomotic leaks and the timely treatment in these cases are...

  16. ENDOCRINE DISRUPTING EFFECTS OF BUTYLPARABEN: A REVIEW

    OpenAIRE

    Pallabi Goswami; J.C Kalita

    2013-01-01

    In recent years, there has been an increasing concern in the field of endocrine disruption over the presence of various endocrine disrupting chemicals in Pharmaceuticals and Personal care products (PPCPs). This concern has also been as PPCPs are most widely used and had led to introduction of thousands of new and complex chemicals that enter the environment in large quantities. The effect of the chemicals has not only been restricted to human who are exposed directly to the chemicals or the a...

  17. Disruption Management in Passenger Railway Transportation

    DEFF Research Database (Denmark)

    Jespersen-Groth, Julie; Potthoff, Daniel; Clausen, Jens;

    This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discus...... for related problems in the airline world are discussed as well. Finally, we address the integration of the re-scheduling processes of the timetable, and the resources rolling stock and crew....

  18. Human immunodeficiency virus-associated disruption of mucosal barriers and its role in HIV transmission and pathogenesis of HIV/AIDS disease.

    Science.gov (United States)

    Tugizov, Sharof

    2016-01-01

    Oral, intestinal and genital mucosal epithelia have a barrier function to prevent paracellular penetration by viral, bacterial and other pathogens, including human immunodeficiency virus (HIV). HIV can overcome these barriers by disrupting the tight and adherens junctions of mucosal epithelia. HIV-associated disruption of epithelial junctions may also facilitate paracellular penetration and dissemination of other viral pathogens. This review focuses on possible molecular mechanisms of HIV-associated disruption of mucosal epithelial junctions and its role in HIV transmission and pathogenesis of HIV and acquired immune deficiency syndrome (AIDS). PMID:27583187

  19. Mechanistic evaluation of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Taxvig, Camilla

    BACKGROUND: This PhD project is part of the research area concerning effects of endocrine disrupters at the National Food Institute at DTU in Denmark. Endocrine disrupting chemicals (EDCs) have proved to be important for improper development of the male reproductive organs and subsequent for the ...... metabolising system using liver S9 mixtures or hepatic rat microsomes could be a convenient method for the incorporation of metabolic aspects into in vitro testing for endocrine disrupting effects.......BACKGROUND: This PhD project is part of the research area concerning effects of endocrine disrupters at the National Food Institute at DTU in Denmark. Endocrine disrupting chemicals (EDCs) have proved to be important for improper development of the male reproductive organs and subsequent......, to be able to detect effects and predict mixture effects. In addition, a new hypothesis have emerge concerning a potential role of exposure to endocrine disrupting chemicals, and the development of obesity and obesity related diseases. AIM: This PhD project aimed to gain more information regarding...

  20. Airline Disruption Management - Perspectives, Experiences and Outlook

    DEFF Research Database (Denmark)

    Kohl, Niklas; Larsen, Allan; Larsen, Jesper;

    2004-01-01

    Over the past decade, airlines have become more concerned with developing an optimal flight schedule, with very little slack left to accommodate for any form of variation from the optimal solution. During operation the planned schedules often have to be revised due to disruptions caused by for ex......Over the past decade, airlines have become more concerned with developing an optimal flight schedule, with very little slack left to accommodate for any form of variation from the optimal solution. During operation the planned schedules often have to be revised due to disruptions caused...... by for example severe weather, technical problems and crew sickness. Thus, the field of Airline Disruption Management has emerged within the past few years. The increased focus on cutting cost at the major airlines has intensified the interest in the development of new and cost e cient methods to handle airline...... disruptions. The purpose of this paper is twofold. In the first part it o ers an introduction to airline disruption management, provides the readers with a description of the planning processes and delivers a detailed overview of the numerous aspects of airline disruption management. In the second part we...

  1. Airline Disruption Management - Perspectives, Experiences and Outlook

    DEFF Research Database (Denmark)

    Kohl, Niklas; Larsen, Allan; Larsen, Jesper;

    2007-01-01

    Over the past decade, airlines have become more concerned with developing an optimal flight schedule, with very little slack left to accommodate for any form of variation from the optimal solution. During operation the planned schedules often have to be revised due to disruptions caused by for ex......Over the past decade, airlines have become more concerned with developing an optimal flight schedule, with very little slack left to accommodate for any form of variation from the optimal solution. During operation the planned schedules often have to be revised due to disruptions caused...... by for example severe weather, technical problems and crew sickness. Thus, the field of Airline Disruption Management has emerged within the past few years. The increased focus on cutting cost at the major airlines has intensified the interest in the development of new and cost efficient methods to handle...... airline disruptions. The purpose of this paper is twofold. In the first part it offers an introduction to airline disruption management provides the readers with a description of the planning processes and delivers a detailed overview of the numerous aspects of airline disruption management. In the second...

  2. Diagnosis of bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Đukić Slobodanka

    2013-01-01

    Full Text Available Bacterial vaginosis is a common, complex clinical syndrome characterized by alterations in the normal vaginal flora. When symptomatic, it is associated with a malodorous vaginal discharge and on occasion vaginal burning or itching. Under normal conditions, lactobacilli constitute 95% of the bacteria in the vagina. Bacterial vaginosis is associated with severe reduction or absence of the normal H2O2­producing lactobacilli and overgrowth of anaerobic bacteria and Gardnerella vaginalis, Atopobium vaginae, Mycoplasma hominis and Mobiluncus species. Most types of infectious disease are diagnosed by culture, by isolating an antigen or RNA/DNA from the microbe, or by serodiagnosis to determine the presence of antibodies to the microbe. Therefore, demonstration of the presence of an infectious agent is often a necessary criterion for the diagnosis of the disease. This is not the case for bacterial vaginosis, since the ultimate cause of the disease is not yet known. There are a variety of methods for the diagnosis of bacterial vaginosis but no method can at present be regarded as the best. Diagnosing bacterial vaginosis has long been based on the clinical criteria of Amsel, whereby three of four defined criteria must be satisfied. Nugent’s scoring system has been further developed and includes validation of the categories of observable bacteria structures. Up­to­date molecular tests are introduced, and better understanding of vaginal microbiome, a clear definition for bacterial vaginosis, and short­term and long­term fluctuations in vaginal microflora will help to better define molecular tests within the broader clinical context.

  3. Bacterial glycosyltransferase toxins.

    Science.gov (United States)

    Jank, Thomas; Belyi, Yury; Aktories, Klaus

    2015-12-01

    Mono-glycosylation of host proteins is a common mechanism by which bacterial protein toxins manipulate cellular functions of eukaryotic target host cells. Prototypic for this group of glycosyltransferase toxins are Clostridium difficile toxins A and B, which modify guanine nucleotide-binding proteins of the Rho family. However, toxin-induced glycosylation is not restricted to the Clostridia. Various types of bacterial pathogens including Escherichia coli, Yersinia, Photorhabdus and Legionella species produce glycosyltransferase toxins. Recent studies discovered novel unexpected variations in host protein targets and amino acid acceptors of toxin-catalysed glycosylation. These findings open new perspectives in toxin as well as in carbohydrate research.

  4. Alternatives to overcoming bacterial resistances: State-of-the-art.

    Science.gov (United States)

    Rios, Alessandra C; Moutinho, Carla G; Pinto, Flávio C; Del Fiol, Fernando S; Jozala, Angela; Chaud, Marco V; Vila, Marta M D C; Teixeira, José A; Balcão, Victor M

    2016-10-01

    Worldwide, bacterial resistance to chemical antibiotics has reached such a high level that endangers public health. Presently, the adoption of alternative strategies that promote the elimination of resistant microbial strains from the environment is of utmost importance. This review discusses and analyses several (potential) alternative strategies to current chemical antibiotics. Bacteriophage (or phage) therapy, although not new, makes use of strictly lytic phage particles as an alternative, or a complement, in the antimicrobial treatment of bacterial infections. It is being rediscovered as a safe method, because these biological entities devoid of any metabolic machinery do not possess any affinity whatsoever to eukaryotic cells. Lysin therapy is also recognized as an innovative antimicrobial therapeutic option, since the topical administration of preparations containing purified recombinant lysins with amounts in the order of nanograms, in infections caused by Gram-positive bacteria, demonstrated a high therapeutic potential by causing immediate lysis of the target bacterial cells. Additionally, this therapy exhibits the potential to act synergistically when combined with certain chemical antibiotics already available on the market. Another potential alternative antimicrobial therapy is based on the use of antimicrobial peptides (AMPs), amphiphilic polypeptides that cause disruption of the bacterial membrane and can be used in the treatment of bacterial, fungal and viral infections, in the prevention of biofilm formation, and as antitumoral agents. Interestingly, bacteriocins are a common strategy of bacterial defense against other bacterial agents, eliminating the potential opponents of the former and increasing the number of available nutrients in the environment for their own growth. They can be applied in the food industry as biopreservatives and as probiotics, and also in fighting multi-resistant bacterial strains. The use of antibacterial antibodies

  5. Mechanical algal disruption for efficient biodiesel extraction

    Science.gov (United States)

    Krehbiel, Joel David

    Biodiesel from algae provides several benefits over current biodiesel feedstocks, but the energy requirements of processing algae into a useable fuel are currently so high as to be prohibitive. One route to improving this is via disruption of the cells prior to lipid extraction, which can significantly increase energy recovery. Unfortunately, several obvious disruption techniques require more energy than can be gained. This dissertation examines the use of microbubbles to improve mechanical disruption of algal cells using experimental, theoretical, and computational methods. New laboratory experiments show that effective ultrasonic disruption of algae is achieved by adding microbubbles to an algal solution. The configuration studied flows the solution through a tube and insonifies a small section with a high-pressure ultrasound wave. Previous biomedical research has shown effective cell membrane damage on animal cells with similar methods, but the present research is the first to extend such study to algal cells. Results indicate that disruption increases with peak negative pressure between 1.90 and 3.07 MPa and with microbubble concentration up to 12.5 x 107 bubbles/ml. Energy estimates of this process suggest that it requires only one-fourth the currently most-efficient laboratory-scale disruption process. Estimates of the radius near each bubble that causes disruption (i.e. the disruption radius) suggest that it increases with peak negative pressure and is near 9--20 microm for all cases tested. It is anticipated that these procedures can be designed for better efficiency and efficacy, which will be facilitated by identifying the root mechanisms of the bubble-induced disruption. We therefore examine whether bubble expansion alone creates sufficient cell deformation for cell rupture. The spherically-symmetric Marmottant model for bubble dynamics allows estimation of the flow regime under experimental conditions. Bubble expansion is modeled as a point source of

  6. Seizures Complicating Bacterial Meningitis

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-09-01

    Full Text Available The clinical data of 116 patients, 1 month to <5 years of age, admitted for bacterial meningitis, and grouped according to those with and without seizures during hospitalization, were compared in a study at Buddhist Dalin Tzu Chi General Hospital, Chang Gung Memorial Hospital and other centers in Taiwan.

  7. Bacterial extracellular lignin peroxidase

    Science.gov (United States)

    Crawford, Donald L.; Ramachandra, Muralidhara

    1993-01-01

    A newly discovered lignin peroxidase enzyme is provided. The enzyme is obtained from a bacterial source and is capable of degrading the lignin portion of lignocellulose in the presence of hydrogen peroxide. The enzyme is extracellular, oxidative, inducible by lignin, larch wood xylan, or related substrates and capable of attacking certain lignin substructure chemical bonds that are not degradable by fungal lignin peroxidases.

  8. Bacterial Skin Infections

    Science.gov (United States)

    ... or scraped, the injury should be washed with soap and water and covered with a sterile bandage. Petrolatum may be applied to open areas to keep the tissue moist and to try to prevent bacterial invasion. Doctors recommend that people do not use ...

  9. Vimentin in Bacterial Infections

    DEFF Research Database (Denmark)

    Mak, Tim N; Brüggemann, Holger

    2016-01-01

    filaments (IFs). IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge...

  10. Bacterial microflora of nectarines

    Science.gov (United States)

    Microflora of fruit surfaces has been the best source of antagonists against fungi causing postharvest decays of fruit. However, there is little information on microflora colonizing surfaces of fruits other than grapes, apples, and citrus fruit. We characterized bacterial microflora on nectarine f...

  11. Modeling intraocular bacterial infections.

    Science.gov (United States)

    Astley, Roger A; Coburn, Phillip S; Parkunan, Salai Madhumathi; Callegan, Michelle C

    2016-09-01

    Bacterial endophthalmitis is an infection and inflammation of the posterior segment of the eye which can result in significant loss of visual acuity. Even with prompt antibiotic, anti-inflammatory and surgical intervention, vision and even the eye itself may be lost. For the past century, experimental animal models have been used to examine various aspects of the pathogenesis and pathophysiology of bacterial endophthalmitis, to further the development of anti-inflammatory treatment strategies, and to evaluate the pharmacokinetics and efficacies of antibiotics. Experimental models allow independent control of many parameters of infection and facilitate systematic examination of infection outcomes. While no single animal model perfectly reproduces the human pathology of bacterial endophthalmitis, investigators have successfully used these models to understand the infectious process and the host response, and have provided new information regarding therapeutic options for the treatment of bacterial endophthalmitis. This review highlights experimental animal models of endophthalmitis and correlates this information with the clinical setting. The goal is to identify knowledge gaps that may be addressed in future experimental and clinical studies focused on improvements in the therapeutic preservation of vision during and after this disease. PMID:27154427

  12. Disruptive Intelligence : How to gather Information to deal with disruptive innovations

    NARCIS (Netherlands)

    Vriens, D.J.; Solberg Søilen, K.

    2014-01-01

    Disruptive innovations are innovations that have the capacity to transform a whole business into one with products that are more accessible and affordable (cf. Christensen et al. 2009). As Christensen et al. argue no business is immune to such disruptive innovations. If these authors are right, it m

  13. Mechanical algal disruption for efficient biodiesel extraction

    Science.gov (United States)

    Krehbiel, Joel David

    Biodiesel from algae provides several benefits over current biodiesel feedstocks, but the energy requirements of processing algae into a useable fuel are currently so high as to be prohibitive. One route to improving this is via disruption of the cells prior to lipid extraction, which can significantly increase energy recovery. Unfortunately, several obvious disruption techniques require more energy than can be gained. This dissertation examines the use of microbubbles to improve mechanical disruption of algal cells using experimental, theoretical, and computational methods. New laboratory experiments show that effective ultrasonic disruption of algae is achieved by adding microbubbles to an algal solution. The configuration studied flows the solution through a tube and insonifies a small section with a high-pressure ultrasound wave. Previous biomedical research has shown effective cell membrane damage on animal cells with similar methods, but the present research is the first to extend such study to algal cells. Results indicate that disruption increases with peak negative pressure between 1.90 and 3.07 MPa and with microbubble concentration up to 12.5 x 107 bubbles/ml. Energy estimates of this process suggest that it requires only one-fourth the currently most-efficient laboratory-scale disruption process. Estimates of the radius near each bubble that causes disruption (i.e. the disruption radius) suggest that it increases with peak negative pressure and is near 9--20 microm for all cases tested. It is anticipated that these procedures can be designed for better efficiency and efficacy, which will be facilitated by identifying the root mechanisms of the bubble-induced disruption. We therefore examine whether bubble expansion alone creates sufficient cell deformation for cell rupture. The spherically-symmetric Marmottant model for bubble dynamics allows estimation of the flow regime under experimental conditions. Bubble expansion is modeled as a point source of

  14. The bacterial microbiome of Dermacentor andersoni ticks influences pathogen susceptibility.

    Science.gov (United States)

    Gall, Cory A; Reif, Kathryn E; Scoles, Glen A; Mason, Kathleen L; Mousel, Michelle; Noh, Susan M; Brayton, Kelly A

    2016-08-01

    Ticks are of medical importance owing to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Although ticks host pathogenic bacteria, they also harbor bacterial endosymbionts that have a role in tick physiology, survival, as well as pathogen acquisition and transmission. The goal of this study was to characterize the bacterial microbiome and examine the impact of microbiome disruption on pathogen susceptibility. The bacterial microbiome of two populations of D. andersoni with historically different susceptibilities to A. marginale was characterized. In this study, the microbiome was disrupted and then ticks were exposed to A. marginale or Francisella novicida to determine whether the microbiome correlated with pathogen susceptibility. Our study showed that an increase in proportion and quantity of Rickettsia bellii in the microbiome was negatively correlated to A. marginale levels in ticks. Furthermore, a decrease in Francisella endosymbionts was associated with lower F. novicida infection levels, demonstrating a positive pathogen-endosymbiont relationship. We demonstrate that endosymbionts and pathogens have varying interactions, and suggest that microbiome manipulation may provide a possible method for biocontrol by decreasing pathogen susceptibility of ticks. PMID:26882265

  15. Bacterial quorum sensing and nitrogen cycling in rhizosphere soil

    Energy Technology Data Exchange (ETDEWEB)

    DeAngelis, K.M.; Lindow, S.E.; Firestone, M.K.

    2008-10-01

    Plant photosynthate fuels carbon-limited microbial growth and activity, resulting in increased rhizosphere nitrogen (N)-mineralization. Most soil organic N is macromolecular (chitin, protein, nucleotides); enzymatic depolymerization is likely rate-limiting for plant N accumulation. Analyzing Avena (wild oat) planted in microcosms containing sieved field soil, we observed increased rhizosphere chitinase and protease specific activities, bacterial cell densities, and dissolved organic nitrogen (DON) compared to bulk soil. Low-molecular weight DON (<3000 Da) was undetectable in bulk soil but comprised 15% of rhizosphere DON. Extracellular enzyme production in many bacteria requires quorum sensing (QS), cell-density dependent group behavior. Because proteobacteria are considered major rhizosphere colonizers, we assayed the proteobacterial QS signals acyl-homoserine lactones (AHLs), which were significantly increased in the rhizosphere. To investigate the linkage between soil signaling and N cycling, we characterized 533 bacterial isolates from Avena rhizosphere: 24% had chitinase or protease activity and AHL production; disruption of QS in 7 of 8 eight isolates disrupted enzyme activity. Many {alpha}-Proteobacteria were newly found with QS-controlled extracellular enzyme activity. Enhanced specific activities of N-cycling enzymes accompanied by bacterial density-dependent behaviors in rhizosphere soil gives rise to the hypothesis that QS could be a control point in the complex process of rhizosphere N-mineralization.

  16. Heme uptake in bacterial pathogens

    OpenAIRE

    Contreras, Heidi; Chim, Nicholas; Credali, Alfredo; Goulding, Celia W.

    2014-01-01

    Iron is an essential nutrient for the survival of organisms. Bacterial pathogens possess specialized pathways to acquire heme from their human hosts. In this review, we present recent structural and biochemical data that provide mechanistic insights into several bacterial heme uptake pathways, encompassing the sequestration of heme from human hemoproteins to secreted or membrane-associated bacterial proteins, the transport of heme across bacterial membranes, and the degradation of heme within...

  17. Disc formation from stellar tidal disruptions

    CERN Document Server

    Bonnerot, Clément; Lodato, Giuseppe; Price, Daniel J

    2015-01-01

    The potential of tidal disruption of stars to probe otherwise quiescent supermassive black holes cannot be exploited, if their dynamics is not fully understood. So far, the observational appearance of these events has been commonly derived from analytical extrapolations of the debris dynamical properties just after the stellar disruption. In this paper, we perform hydrodynamical simulations of stars in highly eccentric orbits, that follow the stellar debris after disruption and investigate their ultimate fate. We demonstrate that gas debris circularize on an orbital timescale because relativistic apsidal precession causes the stream to self-cross. The higher the eccentricity and/or the deeper the encounter, the faster is the circularization. If the internal energy deposited by shocks during stream self-interaction is readily radiated, the gas forms a narrow ring at the circularization radius. It will then proceed to accrete viscously at a super-Eddington rate, puffing up under radiation pressure. If instead c...

  18. Mermaid syndrome with amniotic band disruption.

    Science.gov (United States)

    Managoli, Sanjeev; Chaturvedi, Pushpa; Vilhekar, Krishna Y; Iyenger, Janaki

    2003-01-01

    An association of Amniotic Band Disruption Sequence and Mermaid Syndrome in a newborn having multiple congenital anomalies is being reported. The newborn had aberrant string like tissues attached to the amputed fingers and toes. Adhesions of amniotic bands had disrupted the fetal parts especially anteriorly in the midline, causing multiple anomalies. Apart from these features of Amniotic Band Disruption Sequence, the newborn had complete fusion of the lower limbs by cutaneous tissue, a characteristic of Mermaid Syndrome (Sirenomelia). Associated malformations were anal stenosis, rectal atresia, small horseshoe kidney, hypoplastic urinary bladder and a bicomuate uterus. The single umbilical artery had a high origin, arising directly from the aorta just distal to the celiac axis, which is unique to sirenomelia. Theories put forward regarding the etiopathogenesis of both the conditions are discussed. PMID:12619964

  19. Disruption, beamstrahlung, and beamstrahlung pair creation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P.

    1988-12-01

    The two major effects from the interaction of e/sup /minus//e/sup +/ beams---beamstrahlung and disruption---are reviewed, with emphasis on flat beam collisions. For the disruption effects we discuss the luminosity enhancement factor, the maximum and rms disruption angles, and the ''kink instability''. All the results are obtained from computer simulations, and scaling laws based on these are deduced whenever possible. For the beamstrahlung effects, we concentrate only on the final electron energy spectrum and the deflection angle associated with low energy particles. In addition to the generic studies on the beam-beam effects, we also list the relevant beam-beam parameters obtained from simulations on two sample designs: the TLC and the ILC. As an addendum, the newly discovered phenomenon of coherent beamstrahlung pair creation, together with the incoherent process, are discussed. 18 refs., 15 figs., 1 tab.

  20. Pseudomonas aeruginosa extracellular products inhibit staphylococcal growth, and disrupt established biofilms produced by Staphylococcus epidermidis

    DEFF Research Database (Denmark)

    Qin, Zhiqiang; Yang, Liang; Qu, Di;

    2009-01-01

    Multiple bacterial species often coexist as communities, and compete for environmental resources. Here, we describe how an opportunistic pathogen, Pseudomonas aeruginosa, uses extracellular products to interact with the nosocomial pathogen Staphylococcus epidermidis. S. epidermidis biofilms...... and planktonic cultures were challenged with P. aeruginosa supernatant cultures overnight. Results indicated that quorum-sensing-controlled factors from P. aeruginosa supernatant inhibited S. epidermidis growth in planktonic cultures. We also found that P. aeruginosa extracellular products, mainly...... polysaccharides, disrupted established S. epidermidis biofilms. Cellulase-treated P. aeruginosa supernatant, and supernatant from pelA, ps/F and pe/Aps/BCD mutants, which are deficient in polysaccharide biosynthesis, diminished the disruption of S. epidermidis biofilms. In contrast, S. epidermidis supernatant...

  1. Tidal disruption of stars by SMBHs

    Science.gov (United States)

    Komossa, S.

    2016-06-01

    The tidal disruption and subsequent accretion of stars by supermassive black holes produces spectacular flares in the X-ray sky. First found with ROSAT, ongoing and upcoming sky surveys will find these events in the 1000s. In X-rays, tidal disruption events (TDEs) provide us with powerful new probes of accretion physics under extreme conditions, of the formation of disk winds, of relativistic effects near the SMBH, and of the presence of supermassive binary black holes. This talk reviews the status of observations, and discusses future prospects. XMM-Newton will continue to play an important role in identifying new events and carry out spectroscopic follow-ups.

  2. Abundance Anomalies In Tidal Disruption Events

    OpenAIRE

    Kochanek, C. S.

    2015-01-01

    The ~10% of tidal disruption events (TDEs) due to stars more massive than the Sun should show abundance anomalies due to stellar evolution in helium, carbon and nitrogen, but not oxygen. Helium is always enhanced, but only by up to ~25% on average because it becomes inaccessible once it is sequestered in the high density core as the star leaves the main sequence. However, portions of the debris associated with the disrupted core of a main sequence star can be enhanced in helium by factors of ...

  3. Manufacturing doubt about endocrine disrupter science

    DEFF Research Database (Denmark)

    Bergman, Åke; Becher, Georg; Blumberg, Bruce;

    2015-01-01

    We present a detailed response to the critique of "State of the Science of Endocrine Disrupting Chemicals 2012" (UNEP/WHO, 2013) by financial stakeholders, authored by Lamb et al. (2014). Lamb et al.'s claim that UNEP/WHO (2013) does not provide a balanced perspective on endocrine disruption......) report is not particularly erudite and that their critique is not intended to be convincing to the scientific community, but to confuse the scientific data. Consequently, it promotes misinterpretation of the UNEP/WHO (2013) report by non-specialists, bureaucrats, politicians and other decision makers...

  4. Engineering aspects of disruption current decay

    International Nuclear Information System (INIS)

    Engineering features associated with the configuration of a tokamak can affect the amount of energy that produces melting and damage to the limiters or internal wall surfaces as the result of a major disruption. During the current decay period of a major thermal disruption, the energy that can damage a wall or limiter comes from the external magnetic field. By providing a good conducting torus near the plasma and increasing the plasma circuit resistance, this magnetic energy (transferred by way of the plasma circuit) can be minimized. This report addresses engineering design features to reduce the energy deposited on the inner torus surface that produces melting of the structures

  5. Disruptive Innovation by Emerging Multinational Latecomers

    DEFF Research Database (Denmark)

    Li, Peter Ping

    on disruptive innovation (DI) and the bottom of the pyramid (BOP) provides a great opportunity to shed light on the key issue. To take advantage of this “missed” opportunity, I integrate the two reframed constructs of DI and BOP and also develop a typology of four ideal-typical innovations toward a theory...... of latecomer innovation as a special DI by EMNE at BOP to provide insights into the mechanisms underlying the trajectories of catching up and leapfrogging. Built upon latecomer innovation, EMNEs at BOP can emerge as the most disruptive challengers to the MNE incumbents at TOP. The implications of reframed...

  6. Bacterial chemoreceptors and chemoeffectors.

    Science.gov (United States)

    Bi, Shuangyu; Lai, Luhua

    2015-02-01

    Bacteria use chemotaxis signaling pathways to sense environmental changes. Escherichia coli chemotaxis system represents an ideal model that illustrates fundamental principles of biological signaling processes. Chemoreceptors are crucial signaling proteins that mediate taxis toward a wide range of chemoeffectors. Recently, in deep study of the biochemical and structural features of chemoreceptors, the organization of higher-order clusters in native cells, and the signal transduction mechanisms related to the on-off signal output provides us with general insights to understand how chemotaxis performs high sensitivity, precise adaptation, signal amplification, and wide dynamic range. Along with the increasing knowledge, bacterial chemoreceptors can be engineered to sense novel chemoeffectors, which has extensive applications in therapeutics and industry. Here we mainly review recent advances in the E. coli chemotaxis system involving structure and organization of chemoreceptors, discovery, design, and characterization of chemoeffectors, and signal recognition and transduction mechanisms. Possible strategies for changing the specificity of bacterial chemoreceptors to sense novel chemoeffectors are also discussed.

  7. Bacterial Colony Optimization

    Directory of Open Access Journals (Sweden)

    Ben Niu

    2012-01-01

    Full Text Available This paper investigates the behaviors at different developmental stages in Escherichia coli (E. coli lifecycle and developing a new biologically inspired optimization algorithm named bacterial colony optimization (BCO. BCO is based on a lifecycle model that simulates some typical behaviors of E. coli bacteria during their whole lifecycle, including chemotaxis, communication, elimination, reproduction, and migration. A newly created chemotaxis strategy combined with communication mechanism is developed to simplify the bacterial optimization, which is spread over the whole optimization process. However, the other behaviors such as elimination, reproduction, and migration are implemented only when the given conditions are satisfied. Two types of interactive communication schemas: individuals exchange schema and group exchange schema are designed to improve the optimization efficiency. In the simulation studies, a set of 12 benchmark functions belonging to three classes (unimodal, multimodal, and rotated problems are performed, and the performances of the proposed algorithms are compared with five recent evolutionary algorithms to demonstrate the superiority of BCO.

  8. [Bacterial diseases of rape].

    Science.gov (United States)

    Zakharova, O M; Mel'nychuk, M D; Dankevych, L A; Patyka, V P

    2012-01-01

    Bacterial destruction of the culture was described and its agents identified in the spring and winter rape crops. Typical symptoms are the following: browning of stem tissue and its mucilagization, chlorosis of leaves, yellowing and beginning of soft rot in the place of leaf stalks affixion to stems, loss of pigmentation (violet). Pathogenic properties of the collection strains and morphological, cultural, physiological, and biochemical properties of the agents of rape's bacterial diseases isolated by the authors have been investigated. It was found that all the isolates selected by the authors are highly or moderately aggressive towards different varieties of rape. According to the complex of phenotypic properties 44% of the total number of isolates selected by the authors are related to representatives of the genus Pseudomonas, 37% - to Xanthomonas and 19% - to Pectobacterium. PMID:23293826

  9. Bacterial transformation of terpenoids

    International Nuclear Information System (INIS)

    Data on the bacterial transformation of terpenoids published in the literature in the past decade are analyzed. Possible pathways for chemo-, regio- and stereoselective modifications of terpenoids are discussed. Considerable attention is given to new technological approaches to the synthesis of terpenoid derivatives suitable for the use in the perfume and food industry and promising as drugs and chiral intermediates for fine organic synthesis. The bibliography includes 246 references

  10. Supramolecular bacterial systems

    OpenAIRE

    Sankaran, Shrikrishnan

    2015-01-01

    For nearly over a decade, a wide variety of dynamic and responsive supramolecular architectures have been investigated and developed to address biological systems. Since the non-covalent interactions between individual molecular components in such architectures are similar to the interactions found in living systems, it was possible to integrate chemically-synthesized and naturally-occurring components to create platforms with interesting bioactive properties. Bacterial cells and recombinant ...

  11. Bacterial Colony Optimization

    OpenAIRE

    Ben Niu; Hong Wang

    2012-01-01

    This paper investigates the behaviors at different developmental stages in Escherichia coli (E. coli) lifecycle and developing a new biologically inspired optimization algorithm named bacterial colony optimization (BCO). BCO is based on a lifecycle model that simulates some typical behaviors of E. coli bacteria during their whole lifecycle, including chemotaxis, communication, elimination, reproduction, and migration. A newly created chemotaxis strategy combined with communication mechanism i...

  12. Pediatric small intestine bacterial overgrowth in low-income countries.

    Science.gov (United States)

    Donowitz, Jeffrey R; Petri, William A

    2015-01-01

    Small intestine bacterial overgrowth (SIBO) occurs when colonic quantities of commensal bacteria are present in the small bowel. SIBO is associated with conditions of disrupted gastrointestinal (GI) motility leading to stasis of luminal contents. Recent data show that SIBO is also found in children living in unsanitary conditions who do not have access to clean water. SIBO leads to impaired micronutrient absorption and increased GI permeability, both of which may contribute to growth stunting in children. SIBO also disrupts mucosal immunity and has been implicated in oral vaccination underperformance and the development of celiac disease. SIBO in the setting of the impoverished human habitats may be an under-recognized cause of pediatric morbidity and mortality in the developing world.

  13. The enteropathogenic E. coli effector EspF targets and disrupts the nucleolus by a process regulated by mitochondrial dysfunction.

    Directory of Open Access Journals (Sweden)

    Paul Dean

    Full Text Available The nucleolus is a multifunctional structure within the nucleus of eukaryotic cells and is the primary site of ribosome biogenesis. Almost all viruses target and disrupt the nucleolus--a feature exclusive to this pathogen group. Here, using a combination of bio-imaging, genetic and biochemical analyses, we demonstrate that the enteropathogenic E. coli (EPEC effector protein EspF specifically targets the nucleolus and disrupts a subset of nucleolar factors. Driven by a defined N-terminal nucleolar targeting domain, EspF causes the complete loss from the nucleolus of nucleolin, the most abundant nucleolar protein. We also show that other bacterial species disrupt the nucleolus, dependent on their ability to deliver effector proteins into the host cell. Moreover, we uncover a novel regulatory mechanism whereby nucleolar targeting by EspF is strictly controlled by EPEC's manipulation of host mitochondria. Collectively, this work reveals that the nucleolus may be a common feature of bacterial pathogenesis and demonstrates that a bacterial pathogen has evolved a highly sophisticated mechanism to enable spatio-temporal control over its virulence proteins.

  14. THYROID HORMONE DISRUPTION: FROM KINETICS TO DYNAMICS.

    Science.gov (United States)

    A wide range of chemicals with diverse structures act as thyroid disrupting chemicals (TDCs). Broadly defined, TDCs are chemicals that alter the structure or function of the thyroid gland, alter regulatory enzymes associated with thyroid hormones (THs), or change circulating or t...

  15. The Relative Ineffectiveness of Criminal Network Disruption

    NARCIS (Netherlands)

    P.A.C. Duijn; V. Kashirin; P.M.A. Sloot

    2014-01-01

    Researchers, policymakers and law enforcement agencies across the globe struggle to find effective strategies to control criminal networks. The effectiveness of disruption strategies is known to depend on both network topology and network resilience. However, as these criminal networks operate in se

  16. The relative ineffectiveness of criminal network disruption.

    Science.gov (United States)

    Duijn, Paul A C; Kashirin, Victor; Sloot, Peter M A

    2014-01-01

    Researchers, policymakers and law enforcement agencies across the globe struggle to find effective strategies to control criminal networks. The effectiveness of disruption strategies is known to depend on both network topology and network resilience. However, as these criminal networks operate in secrecy, data-driven knowledge concerning the effectiveness of different criminal network disruption strategies is very limited. By combining computational modeling and social network analysis with unique criminal network intelligence data from the Dutch Police, we discovered, in contrast to common belief, that criminal networks might even become 'stronger', after targeted attacks. On the other hand increased efficiency within criminal networks decreases its internal security, thus offering opportunities for law enforcement agencies to target these networks more deliberately. Our results emphasize the importance of criminal network interventions at an early stage, before the network gets a chance to (re-)organize to maximum resilience. In the end disruption strategies force criminal networks to become more exposed, which causes successful network disruption to become a long-term effort. PMID:24577374

  17. Collisional and Rotational Disruption of Asteroids

    Science.gov (United States)

    Walsh, Kevin J.; Michel, Patrick; Richardson, Derek C.

    2011-02-01

    Asteroids are leftover pieces from the era of planet formation that help us understand conditions in the early Solar System. Unlike larger planetary bodies that were subject to global thermal modification during and subsequent to their formation, these small bodies have kept at least some unmodified primordial material from the solar nebula. However, the structural properties of asteroids have been modified considerably since their formation. Thus, we can find among them a great variety of physical configurations and dynamical histories. In fact, with only a few possible exceptions, all asteroids have been modified or completely disrupted many times during the age of the Solar System. This picture is supported by data from space mission encounters with asteroids that show much diversity of shape, bulk density, surface morphology, and other features. Moreover, the gravitational attraction of these bodies is so small that some physical processes occur in a manner far removed from our common experience on Earth. Thus, each visit to a small body has generated as many questions as it has answered. In this review we discuss the current state of research into asteroid disruption processes, focusing on collisional and rotational mechanisms. We find that recent advances in modeling catastrophic disruption by collisions have provided important insights into asteroid internal structures and a deeper understanding of asteroid families. Rotational disruption, by tidal encounters or thermal effects, is responsible for altering many smaller asteroids, and is at the origin of many binary asteroids and oddly shaped bodies.

  18. Empathy in Boys with Disruptive Behavior Disorders

    Science.gov (United States)

    de Wied, Minet; Goudena, Paul P.; Matthys, Walter

    2005-01-01

    Background: The present study examined empathy in 8- to 12-year-old clinically referred boys with disruptive behavior disorders (DBD) (n = 25) and age-matched normal controls (n = 24). Method: Situational empathy was assessed by children's emotional and cognitive responses to six empathy-inducing vignettes (displaying sadness, anger or happiness).…

  19. The Relative Ineffectiveness of Criminal Network Disruption

    Science.gov (United States)

    Duijn, Paul A. C.; Kashirin, Victor; Sloot, Peter M. A.

    2014-02-01

    Researchers, policymakers and law enforcement agencies across the globe struggle to find effective strategies to control criminal networks. The effectiveness of disruption strategies is known to depend on both network topology and network resilience. However, as these criminal networks operate in secrecy, data-driven knowledge concerning the effectiveness of different criminal network disruption strategies is very limited. By combining computational modeling and social network analysis with unique criminal network intelligence data from the Dutch Police, we discovered, in contrast to common belief, that criminal networks might even become `stronger', after targeted attacks. On the other hand increased efficiency within criminal networks decreases its internal security, thus offering opportunities for law enforcement agencies to target these networks more deliberately. Our results emphasize the importance of criminal network interventions at an early stage, before the network gets a chance to (re-)organize to maximum resilience. In the end disruption strategies force criminal networks to become more exposed, which causes successful network disruption to become a long-term effort.

  20. Five disruptive technology directions for 5G

    DEFF Research Database (Denmark)

    Boccardi, Federico; W. Heath Jr., Robert; Lozano, Angel;

    2014-01-01

    New research directions will lead to fundamental changes in the design of future fifth generation (5G) cellular networks. This article describes five technologies that could lead to both architectural and component disruptive design changes: device-centric architectures, millimeter wave, massive...

  1. Traffic disruption route Einstein near building 170

    CERN Multimedia

    A Lopez - TS/CE

    2005-01-01

    The TS/CE Group informs you that, for the duration of the work at Building 170, there may be some disruption to traffic on route Einstein in the vicinity of Building 170. The work is due to take place from the 14th to 18th February. For more information, please contact 165029. A. Lopez TS/CE

  2. The disruptive effect of Think Aloud

    DEFF Research Database (Denmark)

    Nielsen, Janni; Yssing, Carsten

    2004-01-01

    Think Aloud (TA), we ask the question: what happens when users are required to verbalise their visual perceptions and interactions? We argue that TA may have a disruptive effect, suggesting that other techniques be considered. With a theoretical distinction between focal and subsidiary awareness...

  3. Heavy Metals Acting as Endocrine Disrupters

    Directory of Open Access Journals (Sweden)

    Bogdan Georgescu

    2011-10-01

    Full Text Available Last years researches focused on several natural and synthetic compounds that may interfere with the major functionsof the endocrine system and were termed endocrine disrupters. Endocrine disrupters are defined as chemicalsubstances with either agonist or antagonist endocrine effects in human and animals. These effects may be achievedby interferences with the biosynthesis or activity of several endogenous hormones. Recently, it was demonstratedthat heavy metals such as cadmium (Cd, arsen (As, mercury (Hg, nickel (Ni, lead (Pb and zinc (Zn may exhibitendocrine-disrupting activity in animal experiments. Emerging evidence of the intimate mechanisms of action ofthese heavy metals is accumulating. It was revealed, for example, that the Zn atom from the Zn fingers of theestrogen receptor can be replaced by several heavy metal molecules such as copper, cobalt, Ni and Cd. By replacingthe Zn atom with Ni or copper, binding of the estrogen receptor to the DNA hormone responsive elements in the cellnucleus is prevented. In both males and females, low-level exposure to Cd interferes with the biological effects ofsteroid hormones in reproductive organs. Arsen has the property to bind to the glucocorticoid receptor thusdisturbing glucocorticoids biological effects. With regard to Hg, this may induce alterations in male and femalefertility, may affect the function of the hypothalamo-pituitary-thyroid axis or the hypothalamo-pituitary-adrenal axis,and disrupt biosynthesis of steroid hormones.

  4. Analysis of recent fuel-disruption experiments

    International Nuclear Information System (INIS)

    Recent USDOE-sponsored DEH, FGR, and TREAT F series fuel-disruption experiments are analyzed with existing analytical models. The experiments are interpreted and the results used to evaluate the models. Calculations are presented using the FRAS3 fission-gas-behavior code and the DiMelfi-Deitrich fuel-response model

  5. Hot Super Earths: disrupted young jupiters?

    CERN Document Server

    Nayakshin, Sergei

    2011-01-01

    Recent {\\em Kepler} observations revealed an unexpected abundance of "hot" Earth-size to Neptune-size planets in the inner $0.02-0.2$ AU from their parent stars. We propose that these smaller planets are the remnants of massive giant planets that migrated inward quicker than they could contract. We show that such disruptions naturally occur in the framework of the Tidal Downsizing hypothesis for planet formation. We find that the characteristic planet-star separation at which such "hot disruptions" occur is $R \\approx 0.03-0.2$ AU. This result is independent of the planet's embryo mass but is dependent on the accretion rate in the disc. At high accretion rates, $\\dot M \\simgt 10^{-6}\\msun$ yr$^{-1}$, the embryo is unable to contract quickly enough and is disrupted. At late times, when the accretion rate drops to $\\dot M \\simlt 10^{-8} \\msun$ yr$^{-1}$, the embryos migrate sufficiently slow to not be disrupted. These "late arrivals" may explain the well known population of hot jupiters. If type I migration reg...

  6. Analysis of recent fuel-disruption experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, J.M.; Kraft, T.E.; DiMelfi, R.J.; Fenske, G.R.; Gruber, E.E.

    1982-01-01

    Recent USDOE-sponsored DEH, FGR, and TREAT F series fuel-disruption experiments are analyzed with existing analytical models. The experiments are interpreted and the results used to evaluate the models. Calculations are presented using the FRAS3 fission-gas-behavior code and the DiMelfi-Deitrich fuel-response model.

  7. Mechanisms of Bacterial Extracellular Electron Exchange.

    Science.gov (United States)

    White, G F; Edwards, M J; Gomez-Perez, L; Richardson, D J; Butt, J N; Clarke, T A

    2016-01-01

    The biochemical mechanisms by which microbes interact with extracellular soluble metal ions and insoluble redox-active minerals have been the focus of intense research over the last three decades. The process presents two challenges to the microorganism. Firstly, electrons have to be transported at the cell surface, which in Gram-negative bacteria presents an additional problem of electron transfer across the ~6nm of the outer membrane. Secondly, the electrons must be transferred to or from the terminal electron acceptors or donors. This review covers the known mechanisms that bacteria use to transport electrons across the cell envelope to external electron donors/acceptors. In Gram-negative bacteria, electron transfer across the outer membrane involves the use of an outer membrane β-barrel and cytochrome. These can be in the form of a porin-cytochrome protein, such as Cyc2 of Acidithiobacillus ferrooxidans, or a multiprotein porin-cytochrome complex like MtrCAB of Shewanella oneidensis MR-1. For mineral-respiring organisms, there is the additional challenge of transferring the electrons from the cell to mineral surface. For the strict anaerobe Geobacter sulfurreducens this requires electron transfer through conductive pili to associated cytochrome OmcS that directly reduces Fe(III)oxides, while the facultative anaerobe S. oneidensis MR-1 accomplishes mineral reduction through direct membrane contact, contact through filamentous extensions and soluble flavin shuttles, all of which require the outer membrane cytochromes MtrC and OmcA in addition to secreted flavin. PMID:27134022

  8. Engineering bioinspired bacteria-adhesive clay nanoparticles with a membrane-disruptive property for the treatment of Helicobacter pylori infection.

    Science.gov (United States)

    Ping, Yuan; Hu, Xiurong; Yao, Qi; Hu, Qida; Amini, Shahrouz; Miserez, Ali; Tang, Guping

    2016-09-28

    We present a bioinspired design strategy to engineer bacteria-targeting and membrane-disruptive nanoparticles for the effective antibiotic therapy of Helicobacter pylori (H. pylori) infection. Antibacterial nanoparticles were self-assembled from highly exfoliated montmorillonite (eMMT) and cationic linear polyethyleneimine (lPEI) via electrostatic interactions. eMMT functions as a bioinspired 'sticky' building block for anchoring antibacterial nanoparticles onto the bacterial cell surface via bacteria-secreted extracellular polymeric substances (EPS), whereas membrane-disruptive lPEI is able to efficiently lyse the bacterial outer membrane to allow topical transmembrane delivery of antibiotics into the intracellular cytoplasm. As a result, eMMT-lPEI nanoparticles intercalated with the antibiotic metronidazole (MTZ) not only efficiently target bacteria via EPS-mediated adhesion and kill bacteria in vitro, but also can effectively remain in the stomach where H. pylori reside, thereby serving as an efficient drug carrier for the direct on-site release of MTZ into the bacterial cytoplasm. Importantly, MTZ-intercalated eMMT-lPEI nanoparticles were able to efficiently eradicate H. pylori in vivo and to significantly improve H. pylori-associated gastric ulcers and the inflammatory response in a mouse model, and also showed superior therapeutic efficacy as compared to standard triple therapy. Our findings reveal that bacterial adhesion plays a critical role in promoting efficient antimicrobial delivery and also represent an original bioinspired targeting strategy via specific EPS-mediated adsorption. The bacteria-adhesive eMMT-lPEI nanoparticles with membrane-disruptive ability may constitute a promising drug carrier system for the efficacious targeted delivery of antibiotics in the treatment of bacterial infections.

  9. Change in hydrophilicity of penicillins during advanced oxidation by radiolytically generated OH compromises the elimination of selective pressure on bacterial strains.

    Science.gov (United States)

    Szabó, László; Tóth, Tünde; Engelhardt, Tekla; Rácz, Gergely; Mohácsi-Farkas, Csilla; Takács, Erzsébet; Wojnárovits, László

    2016-05-01

    Advanced oxidation processes are promising technologies for removal of antibiotic residues from wastewater in terms of their high efficacy. However, recent studies have reported the remaining antibacterial activity of the products at early-stages of treatment. The present study investigates the effect of such products of model β-lactams (amoxicillin, ampicillin, cloxacillin) on bacteria introducing structure-based, and biological approaches involving Gram-positive and Gram-negative bacterial strains. Chemical analysis revealed the destruction of the β-lactam pharmacophore in competition with the reaction at the aromatic ring. Multisite attack occurs on the penicillin skeleton producing OH-substituted products. The enhanced hydrophilicity confers higher diffusion rate through the porin channels of Gram-negative bacteria and through the hydrophilic cell wall of Gram-positive species. Accordingly, an increase in acute toxicity of treated samples was observed at the beginning of the treatment. The same tendency was observed for target-specific antimicrobial activity investigated with antibiotic susceptibility testing (agar-diffusion, bacterial growth). Prolonged treatments yielded products, e.g. polyhydroxylated phenolic compounds, being also deleterious for bacteria. Therefore, the advanced oxidation process should be judiciously optimized. PMID:26881730

  10. Bacterial Cellular Engineering by Genome Editing and Gene Silencing

    Directory of Open Access Journals (Sweden)

    Nobutaka Nakashima

    2014-02-01

    Full Text Available Genome editing is an important technology for bacterial cellular engineering, which is commonly conducted by homologous recombination-based procedures, including gene knockout (disruption, knock-in (insertion, and allelic exchange. In addition, some new recombination-independent approaches have emerged that utilize catalytic RNAs, artificial nucleases, nucleic acid analogs, and peptide nucleic acids. Apart from these methods, which directly modify the genomic structure, an alternative approach is to conditionally modify the gene expression profile at the posttranscriptional level without altering the genomes. This is performed by expressing antisense RNAs to knock down (silence target mRNAs in vivo. This review describes the features and recent advances on methods used in genomic engineering and silencing technologies that are advantageously used for bacterial cellular engineering.

  11. Disruption of biofilms from sewage pipes under physical and chemical conditioning

    Institute of Scientific and Technical Information of China (English)

    Charbel Mahfoud; Antoine El Samrani; Rita Mouawad; Walid Hleihel; Rim El Khatib; Bruno S. Lartiges; Naim Ouaini

    2009-01-01

    Biofilms grown inside two sewage collecting pipes located in industrial and residential areas are studied. Bacterial biomass inside three layers of biofilms was evaluated. Biofilm cohesion under different mixing rate and ionic strength was also investigated. Effects of physical and chemical parameters in the biofilms were evaluated by monitoring turbidity, chemical and biochemical oxygen demands. Extracted organic matter from biofilms was partitioned to polar, aromatic and saturated fractions using activated silica column chromatography. Results revealed that bacterial biomass growth depending on biofilm thickness and stratification. The most loaded stratum in bacterial biomass was the sewage-biofilm interface stratum that represented 51% of the total bacterial biomass. Stirring rate and ionic strength of mono and bivalent salts showed a major influence in biofilm disruption. The stirring time enhanced the exchange dynamic and matter capture between biofilm fragments at the critical stirring rate 90 r/min. Sodium chloride showed the dispersing effect on biofilms in suspension, and decreased the BOD5 (biochemical oxygen demand) beyond the physiological salt concentration.

  12. Mucosal reactive oxygen species decrease virulence by disrupting Campylobacter jejuni phosphotyrosine signaling.

    Science.gov (United States)

    Corcionivoschi, Nicolae; Alvarez, Luis A J; Sharp, Thomas H; Strengert, Monika; Alemka, Abofu; Mantell, Judith; Verkade, Paul; Knaus, Ulla G; Bourke, Billy

    2012-07-19

    Reactive oxygen species (ROS) play key roles in mucosal defense, yet how they are induced and the consequences for pathogens are unclear. We report that ROS generated by epithelial NADPH oxidases (Nox1/Duox2) during Campylobacter jejuni infection impair bacterial capsule formation and virulence by altering bacterial signal transduction. Upon C. jejuni invasion, ROS released from the intestinal mucosa inhibit the bacterial phosphotyrosine network that is regulated by the outer-membrane tyrosine kinase Cjtk (Cj1170/OMP50). ROS-mediated Cjtk inactivation results in an overall decrease in the phosphorylation of C. jejuni outer-membrane/periplasmic proteins, including UDP-GlcNAc/Glc 4-epimerase (Gne), an enzyme required for N-glycosylation and capsule formation. Cjtk positively regulates Gne by phosphorylating an active site tyrosine, while loss of Cjtk or ROS treatment inhibits Gne activity, causing altered polysaccharide synthesis. Thus, epithelial NADPH oxidases are an early antibacterial defense system in the intestinal mucosa that modifies virulence by disrupting bacterial signaling.

  13. Disruptive behavior in school. Wired up - the relationship between disruptive behavior and new technology.

    OpenAIRE

    Solberg, Stine

    2014-01-01

    Background: The thesis is part of the research project Disruptive behavior in school, led by professor Liv Duesund at the Department of Special Needs Education, University of Oslo. Professor Duesund is the supervisor of the thesis. It is a cooperation project between University of Oslo and University of California, Berkeley and compares the educational cultures of Norway an the United States (Duesund, 2013). The focus is on disruptive behavior, and in what ways behavior can vary in the two ...

  14. Lysine-Based Small Molecules That Disrupt Biofilms and Kill both Actively Growing Planktonic and Nondividing Stationary Phase Bacteria.

    Science.gov (United States)

    Konai, Mohini M; Haldar, Jayanta

    2015-10-01

    The emergence of bacterial resistance is a major threat to global health. Alongside this issue, formation of bacterial biofilms is another cause of concern because most antibiotics are ineffective against these recalcitrant microbial communities. Ideal future antibacterial therapeutics should possess both antibacterial and anti-biofilm activities. In this study we engineered lysine-based small molecules, which showed not only commendable broad-spectrum antibacterial activity but also potent biofilm-disrupting properties. Synthesis of these lipophilic lysine-norspermidine conjugates was achieved in three simple reaction steps, and the resultant molecules displayed potent antibacterial activity against various Gram-positive (Staphylococcus aureus, Enterococcus faecium) and Gram-negative bacteria (Escherichia coli) including drug-resistant superbugs MRSA (methicillin-resistant S. aureus), VRE (vancomycin-resistant E. faecium), and β-lactam-resistant Klebsiella pneumoniae. An optimized compound in the series showed activity against planktonic bacteria in the concentration range of 3-10 μg/mL, and bactericidal activity against stationary phase S. aureus was observed within an hour. The compound also displayed about 120-fold selectivity toward both classes of bacteria (S. aureus and E. coli) over human erythrocytes. This rapidly bactericidal compound primarily acts on bacteria by causing significant membrane depolarization and K(+) leakage. Most importantly, the compound disrupted preformed biofilms of S. aureus and did not trigger bacterial resistance. Therefore, this class of compounds has high potential to be developed as future antibacterial drugs for treating infections caused by planktonic bacteria as well as bacterial biofilms. PMID:27623313

  15. Longitudinal association between marital disruption and child BMI and obesity.

    Science.gov (United States)

    Arkes, Jeremy

    2012-08-01

    This research examines whether family disruptions (i.e., divorces and separation) contribute to children's weight problems. The sample consists of 7,299 observations for 2,333 children, aged 5-14, over the 1986-2006 period, from a US representative sample from the Child and Young Adult Survey accompanying the National Longitudinal Survey of Youth (NLSY). The study uses individual-fixed-effects models in a longitudinal framework to compare children's BMI and weight problems before and after a disruption. Furthermore, besides doing a before-after comparison for children, the study also estimates the effects at various periods relative to the disruption in order to examine whether children are affected before the disruption and whether any effects change as time passes from the disruption, as some effects may be temporary or slow to develop. Despite having a larger sample than the previous studies, the results provide no evidence that, on average, children's BMI and BMI percentile scores (measured with continuous outcomes) are affected before the disruption, after the disruption, and as time passes from the disruption, relative to a baseline period a few years before the disruption. However, children experiencing a family disruption do have an increased risk of obesity (having a BMI percentile score of 95 or higher) in the two years leading up to the disruption as well as after the disruption, and as time passes from the disruption. PMID:22484366

  16. Markers of bacterial translocation in end-stage liver disease

    Institute of Scientific and Technical Information of China (English)

    Ioannis; Koutsounas; Garyfallia; Kaltsa; Spyros; I; Siakavellas; Giorgos; Bamias

    2015-01-01

    Bacterial translocation(BT) refers to the passage of viable bacteria or bacterial products from the intestinal lumen, through the intestinal epithelium, into the systemic circulation and extraintestinal locations. The three principal mechanisms that are thought to be involved in BT include bacterial overgrowth, disruption of the gut mucosal barrier and an impaired host defence.BT is commonly observed in liver cirrhosis and has been shown to play an important role in the pathogenesis of the complications of end stage liver disease, including infections as well as hepatic encephalopathy and hepatorenal syndrome. Due to the importance of BT in the natural history of cirrhosis, there is intense interest for the discovery of biomarkers of BT. To date, several such candidates have been proposed, which include bacterial DNA, soluble CD14, lipopolysaccharides endotoxin, lipopolysaccharide-binding protein, calprotectin and procalcitonin. Studies on the association of these markers with BT have demonstrated not only promising data but, oftentimes, contradictory results. As a consequence, currently, there is no optimal marker that may be used in clinical practice as a surrogate for the presence of BT.

  17. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Rafi eRashid

    2016-06-01

    Full Text Available Antimicrobial peptides (AMPs are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs target anionic lipids (e.g. phosphatidylglycerol (PG and cardiolipins (CL in the cell membrane and anionic components (e.g. lipopolysaccharide (LPS and lipoteichoic acid (LTA of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g. lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1 CAMP disruption mechanisms, (2 delocalization of membrane proteins and lipids by CAMPs, and (3 CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging and non-detergent-based membrane domain extraction.

  18. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides.

    Science.gov (United States)

    Rashid, Rafi; Veleba, Mark; Kline, Kimberly A

    2016-01-01

    Antimicrobial peptides (AMPs) are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs) target anionic lipids [e.g., phosphatidylglycerol (PG) and cardiolipins (CL)] in the cell membrane and anionic components [e.g., lipopolysaccharide (LPS) and lipoteichoic acid (LTA)] of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g., lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1) CAMP disruption mechanisms, (2) delocalization of membrane proteins and lipids by CAMPs, and (3) CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging, and non-detergent-based membrane domain extraction. PMID:27376064

  19. Normal flora and bacterial vaginosis in pregnancy: an overview.

    Science.gov (United States)

    Redelinghuys, Mathys Jacobus; Ehlers, Marthie Magdaleen; Dreyer, Andries William; Kock, Marleen Magdalena

    2016-05-01

    The female genital tract is an intricate, yet balanced ecosystem that hosts a variety of different residential microflora. The physiological changes that occur during pregnancy may disrupt this balanced ecosystem and predispose women to a potentially pathogenic microbiota. Bacteria that are associated with bacterial vaginosis (BV) are opportunistic pathogens that frequently form part of this microbiota. The overgrowth of and infections with these bacteria are linked to poor obstetric outcomes and increased transmission of other reproductive tract infections (RTIs). These infections increase women's susceptibility of acquiring HIV, the rates of HIV shedding and the development of acquired immune deficiency syndrome (AIDS) in HIV-infected patients. It is unknown how the plethora of bacterial species associated with BV contributes to the dynamics of this condition. The use of high-throughput methods have led to the in-depth investigation of different BV-related bacterial species and the functional capabilities of these species. However, the pathogenesis of BV is still poorly defined and the role of individual BV-related bacterial species in specific pregnancy complications is unclear and controversial. The majority of BV infections are asymptomatic and successful diagnosis is complicated by the lack of reliable and standardized diagnostic tests. PMID:25834920

  20. Isolation of biologically active nanomaterial (inclusion bodies from bacterial cells

    Directory of Open Access Journals (Sweden)

    Peternel Špela

    2010-09-01

    Full Text Available Abstract Background In recent years bacterial inclusion bodies (IBs were recognised as highly pure deposits of active proteins inside bacterial cells. Such active nanoparticles are very interesting for further downstream protein isolation, as well as for many other applications in nanomedicine, cosmetic, chemical and pharmaceutical industry. To prepare large quantities of a high quality product, the whole bioprocess has to be optimised. This includes not only the cultivation of the bacterial culture, but also the isolation step itself, which can be of critical importance for the production process. To determine the most appropriate method for the isolation of biologically active nanoparticles, three methods for bacterial cell disruption were analyzed. Results In this study, enzymatic lysis and two mechanical methods, high-pressure homogenization and sonication, were compared. During enzymatic lysis the enzyme lysozyme was found to attach to the surface of IBs, and it could not be removed by simple washing. As this represents an additional impurity in the engineered nanoparticles, we concluded that enzymatic lysis is not the most suitable method for IBs isolation. During sonication proteins are released (lost from the surface of IBs and thus the surface of IBs appears more porous when compared to the other two methods. We also found that the acoustic output power needed to isolate the IBs from bacterial cells actually damages proteins structures, thereby causing a reduction in biological activity. High-pressure homogenization also caused some damage to IBs, however the protein loss from the IBs was negligible. Furthermore, homogenization had no side-effects on protein biological activity. Conclusions The study shows that among the three methods tested, homogenization is the most appropriate method for the isolation of active nanoparticles from bacterial cells.

  1. Spontaneous bacterial peritonitis

    Institute of Scientific and Technical Information of China (English)

    Anastasios Koulaouzidis; Shivaram Bhat; Athar A Saeed

    2009-01-01

    Since its initial description in 1964, research has transformed spontaneous bacterial peritonitis (SBP) from a feared disease (with reported mortality of 90%) to a treatable complication of decompensated cirrhosis,albeit with steady prevalence and a high recurrence rate. Bacterial translocation, the key mechanism in the pathogenesis of SBP, is only possible because of the concurrent failure of defensive mechanisms in cirrhosis.Variants of SBP should be treated. Leucocyte esterase reagent strips have managed to shorten the 'tap-toshot' time, while future studies should look into their combined use with ascitic fluid pH. Third generation cephalosporins are the antibiotic of choice because they have a number of advantages. Renal dysfunction has been shown to be an independent predictor of mortality in patients with SBP. Albumin is felt to reduce the risk of renal impairment by improving effective intravascular volume, and by helping to bind proinflammatory molecules. Following a single episode of SBP, patients should have long-term antibiotic prophylaxis and be considered for liver transplantation.

  2. Antimicrobials for bacterial bioterrorism agents.

    Science.gov (United States)

    Sarkar-Tyson, Mitali; Atkins, Helen S

    2011-06-01

    The limitations of current antimicrobials for highly virulent pathogens considered as potential bioterrorism agents drives the requirement for new antimicrobials that are suitable for use in populations in the event of a deliberate release. Strategies targeting bacterial virulence offer the potential for new countermeasures to combat bacterial bioterrorism agents, including those active against a broad spectrum of pathogens. Although early in the development of antivirulence approaches, inhibitors of bacterial type III secretion systems and cell division mechanisms show promise for the future.

  3. Disruption of cytoplasmic microtubules by ultraviolet radiation

    International Nuclear Information System (INIS)

    Ultraviolet (UV) irradiation of cultured human skin fibroblasts causes the disassembly of their microtubules. Using indirect immunofluorescence microscopy, we have now investigated whether damage to the microtubule precursor pool may contribute to the disruption of microtubules. Exposure to polychromatic UV radiation inhibits the reassembly of microtubules during cellular recovery from cold treatment. In addition, the ability of taxol to promote microtubule polymerization and bundling is inhibited in UV-irradiated cells. However, UV irradiation of taxol-pretreated cells or in situ detergent-extracted microtubules fails to disrupt the microtubule network. These data suggest that damage to dimeric tubulin, or another soluble factor(s) required for polymerization, contributes to the disassembly of microtubules in UV-irradiated human skin fibroblasts

  4. The hexagon hypothesis: Six disruptive scenarios.

    Science.gov (United States)

    Burtles, Jim

    2015-01-01

    This paper aims to bring a simple but effective and comprehensive approach to the development, delivery and monitoring of business continuity solutions. To ensure that the arguments and principles apply across the board, the paper sticks to basic underlying concepts rather than sophisticated interpretations. First, the paper explores what exactly people are defending themselves against. Secondly, the paper looks at how defences should be set up. Disruptive events tend to unfold in phases, each of which invites a particular style of protection, ranging from risk management through to business continuity to insurance cover. Their impact upon any business operation will fall into one of six basic scenarios. The hexagon hypothesis suggests that everyone should be prepared to deal with each of these six disruptive scenarios and it provides them with a useful benchmark for business continuity. PMID:26420396

  5. Endocrine disrupters. The case of estrogen xenobiotics

    Directory of Open Access Journals (Sweden)

    N. Olea Serrano

    2001-06-01

    Full Text Available Interest of the scientific community in chemical substances able to alter the hormone balance –endocrine disrupters- has grown with increasing evidence of the consequences for animal populations of exposure to these substances. As has occurred on previous occasions, observational data on animal populations have been sufficiently suggestive to cause concerns among clinicians that similar effects may be produced in human populations. Although data on the effects on populations of animals are more easily generated than those on individuals, clinical observations on human individuals alongside the few existing epidemiological studies have shown a certain parallelism. Indeed, in vitro and in vivo models have been able to designate many chemical compounds as hormonal mimics, including both natural and human-produced compounds to which there are exposure risks. The present work reviews the conceptual premises of endocrine disruption and the development of the use of this term.

  6. Cloning and disruption of Ustilago maydis genes.

    OpenAIRE

    Fotheringham, S.; Holloman, W K

    1989-01-01

    We have demonstrated that genes from Ustilago maydis can be cloned by direct complementation of mutants through the use of genomic libraries made in a high-frequency transformation vector. We isolated a gene involved in amino acid biosynthesis as an illustrative example and showed that integrative and one-step disruption methods can be used to create null mutations in the chromosomal copy of the gene by homologous recombination. The results of this investigation make it clear that one-step ge...

  7. The Impact of Disruptive Innovations in Orthopaedics

    OpenAIRE

    Hansen, Erik; Bozic, Kevin J.

    2009-01-01

    The US healthcare system is currently facing daunting demographic and economic challenges. Because musculoskeletal disorders and disease represent a substantial and growing portion of this healthcare burden, novel approaches will be needed to continue to provide high-quality, affordable, and accessible orthopaedic care to our population. The concept of “disruptive innovations,” which has been studied and popularized by Harvard Business School Professor Clayton Christensen, may offer a potenti...

  8. Disruption strategies for online child pornography networks

    OpenAIRE

    Joffres, Kilauea

    2012-01-01

    The advent of the Internet has allowed for the creation of online child pornography networks, in which websites link to one another and facilitate access to child pornographic materials. This project seeks to use social network analysis tools to identify effective disruption strategies against online child pornography networks. For this purpose, four networks of child exploitation material were extracted using a specially designed web-crawler. These networks were then submitted to three diffe...

  9. Mechanical properties and disruption of dental biofilms

    OpenAIRE

    Rmaile, Amir

    2013-01-01

    A literature review of dental plaque biofilms formation, progression and detachment mechanisms is presented in this thesis. Various strategies that have been employed to reduce or eliminate dental biofilms are discussed. The focus of the thesis was on the mechanical properties and disruption of dental biofilms, especially from hard-to-access areas of the oral cavity, such as the interproximal (IP) sites between the teeth. Various methods to measure mechanical properties of dental biofilms wer...

  10. Language adapts to signal disruption in interaction

    OpenAIRE

    Macuch Silva, V.; Roberts, S

    2016-01-01

    Linguistic traits are often seen as reflecting cognitive biases and constraints (e.g. Christiansen & Chater, 2008). However, language must also adapt to properties of the channel through which communication between individuals occurs. Perhaps the most basic aspect of any communication channel is noise. Communicative signals can be blocked, degraded or distorted by other sources in the environment. This poses a fundamental problem for communication. On average, channel disruption accompanies p...

  11. Will disruptive innovations cure health care?

    Science.gov (United States)

    Christensen, C M; Bohmer, R; Kenagy, J

    2000-01-01

    It's no secret that health care delivery is convoluted, expensive, and often deeply dissatisfying to consumers. But what is less obvious is that a way out of this crisis exists. Simpler alternatives to expensive care are already here--everything from $5 eyeglasses that people can use to correct their own vision to angioplasty instead of open-heart surgery. Just as the PC replaced the mainframe and the telephone replaced the telegraph operator, disruptive innovations are changing the landscape of health care. Nurse practitioners, general practitioners, and even patients can do things in less-expensive, decentralized settings that could once be performed only by expensive specialists in centralized, inconvenient locations. But established institutions--teaching hospitals, medical schools, insurance companies, and managed care facilities--are fighting these innovations tooth and nail. Instead of embracing change, they're turning the thumbscrews on their old processes--laying off workers, delaying payments, merging, and adding layers of overhead workers. Not only is this at the root of consumer dissatisfaction with the present system, it sows the seeds of its own destruction. The history of disruptive innovations tells us that incumbent institutions will be replaced with ones whose business models are appropriate to the new technologies and markets. Instead of working to preserve the existing systems, regulators, physicians, and pharmaceutical companies need to ask how they can enable more disruptive innovations to emerge. If the natural process of disruption is allowed to proceed, the result will be higher quality, lower cost, more convenient health care for everyone. PMID:11143147

  12. Disruption of vitamin A metabolism by dioxin

    OpenAIRE

    Högberg, Pi

    2003-01-01

    Vitamin A (retinoids) is a nutrient that plays a central role in development and remains essential for cell growth and differentiation throughout life. Dioxins are polychlorinated organic pollutants known to negatively affect the storage and body clearance of retinoids. This work aimed at studying mechanisms and consequences of dioxin-induced retinoid disruption in vivo. As model compound we used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and as model species adult male S...

  13. Robust scheduling and disruption recovery for airlines

    OpenAIRE

    Eggenberg, Niklaus; Salani, Matteo

    2009-01-01

    Airline planning include complex and structured operations that must be planned in advance in order to exploit the available resources, provide a reliable and competitive service and forecast system's performances. Decisions regarding operations are based on data which is frequently due to uncertainty. Moreover, unpredicted events may disrupt the current schedule and force managers to take reactive decisions to recover to an operational state. On the other hand, proactive decisions, i.e. deci...

  14. Influence of Dynamic Capabilities in Creating Disruptive Innovation

    OpenAIRE

    Čiutienė, R; Thattakath, E

    2015-01-01

    The aim of this paper is to demonstrate the influence of Dynamic Capabilities in creating Disruptive Innovation. For doing so the concepts of Dynamic Capabilities and Disruptive Innovation are reviewed. The criteria of an innovation named Disruptive Innovation are obtained by comparative study between the various innovation types. To demonstrate the role of Dynamic Capabilities in creating Disruptive Innovation, the Innovation Lifecycle is demonstrated with respect to Dynamic Capabilities. Th...

  15. Fungal tools for the degradation of endocrine disrupting compounds

    OpenAIRE

    Kabiersch, Grit

    2013-01-01

    Endocrine disrupting compounds are synthetic or natural compounds that mimic the action of hormones and thus disrupt or alter functions of the endocrine system usually through direct interactions with nuclear receptors. The main objective of this work was to develop strategies of how to degrade endocrine disrupting compounds and how to monitor the removal of the endocrine disrupting effect with focus on the estrogenic compound bisphenol A and on the virilizing compound tributyltin. Bisph...

  16. Fortum, how an incumbent should deal with a disruptive innovation

    OpenAIRE

    Noteboom, Arno

    2014-01-01

    Solar PV as a disruptive innovation is changing the established energy industry. It forces energy incumbents to compete on a new market, and on new features. This research sets out to investigate how Fortum should be dealing with this disruptive innovation. This study is conducted in two parts, first it is analysed what the effects are of solar PV being labelled disruptive. This determines whether Fortum should at all be participating in this new disruptive market. The second part analyse...

  17. Influence of Dynamic Capabilities in Creating Disruptive Innovation

    OpenAIRE

    Čiutienė, R; Thattakath, E

    2014-01-01

    The aim of this paper is to demonstrate the influence of Dynamic Capabilities in creating Disruptive Innovation. For doing so the concepts of Dynamic Capabilities and Disruptive Innovation are reviewed. The criteria of an innovation named Disruptive Innovation are obtained by comparative study between the various innovation types. To demonstrate the role of Dynamic Capabilities in creating Disruptive Innovation, the Innovation Lifecycle is demonstrated with respect to Dynamic Capabilities. Th...

  18. Extensor Mechanism Disruption in Knee Dislocation.

    Science.gov (United States)

    O'Malley, Michael; Reardon, Patrick; Pareek, Ayoosh; Krych, Aaron; Levy, Bruce A; Stuart, Michael J

    2016-05-01

    Disruption of the knee extensor mechanism is a challenging injury with no clear consensus on optimal treatment. Although rare in the setting of knee dislocations, these injuries should not be overlooked. Acute, complete rupture of either the quadriceps or patellar tendon necessitates primary repair with or without augmentation. Surgical management may also be required in the setting of a partial tear if a significant extensor lag is present or nonoperative treatment has failed. Tendon augmentation is used during primary repair if the native tissue is inadequate or after a failed primary repair. The purpose of this study is to evaluate extensor mechanism disruption incidence, injury patterns, associated injuries, and surgical options, including a novel tendon augmentation technique. This procedure consists of primary patellar or quadriceps tendon repair with semitendinosus autograft augmentation utilizing a distal or proximal patellar socket. Advantages of repair with tendon augmentation include accelerated rehabilitation, decreased risk of patellar fracture from transverse or longitudinal bone tunnels, and less hardware complications. We recommend consideration of this technique for selected cases of acute extensor mechanism disruption in the setting of tibiofemoral dislocation. PMID:26636488

  19. Risk Evaluation of Endocrine-Disrupting Chemicals

    Directory of Open Access Journals (Sweden)

    Laura Gioiosa

    2015-10-01

    Full Text Available We review here our studies on early exposure to low doses of the estrogenic endocrine-disrupting chemical bisphenol A (BPA on behavior and metabolism in CD-1 mice. Mice were exposed in utero from gestation day (GD 11 to delivery (prenatal exposure or via maternal milk from birth to postnatal day 7 (postnatal exposure to 10 µg/kg body weight/d of BPA or no BPA (controls. Bisphenol A exposure resulted in long-term disruption of sexually dimorphic behaviors. Females exposed to BPA pre- and postnatally showed increased anxiety and behavioral profiles similar to control males. We also evaluated metabolic effects in prenatally exposed adult male offspring of dams fed (from GD 9 to 18 with BPA at doses ranging from 5 to 50 000 µg/kg/d. The males showed an age-related significant change in a number of metabolic indexes ranging from food intake to glucose regulation at BPA doses below the no observed adverse effect level (5000 µg/kg/d. Consistent with prior findings, low but not high BPA doses produced significant effects for many outcomes. These findings provide further evidence of the potential risks that developmental exposure to low doses of the endocrine disrupter BPA may pose to human health, with fetuses and infants being highly vulnerable.

  20. Physician disruptive behaviors: Five year progress report.

    Science.gov (United States)

    Rosenstein, Alan H

    2015-11-16

    Disruptive behaviors in health care can have a significant adverse effect on staff interactions that can negatively impact staff satisfaction, staff performance, and patient outcomes of care. As referenced in a previously published article, the Obstetrics and Gynecology specialty is one of the service areas where these behaviors occur more frequently. Despite growing evidence of the ill effects of these types of behaviors many organizations are still having a difficult time in addressing these issues in an effective manner. Gaining a better understanding of the nature, causes, and impact of these behaviors is crucial to finding the right remedies for solution. Nobody intentionally starts the day planning to be disruptive, it's just that things get in the way. A combination of deep seated factors related to age and gender preferences, culture and ethnicity, life experiences, and other events that help shape values, attitudes and personalities, and more external factors related to training, environmental pressures, stress and burnout, and other personal issues all contribute to the mix. Given the complexities of today's health care environment, each person needs to recognize the importance of being held accountable for appropriate actions and behaviors that affect work relationships and care coordination that impact patient care. Early recognition, early intervention, and taking a pro-active supportive approach to improve individual behaviors will result in better relationships, less disruption, more satisfaction, and better outcomes of care. PMID:26601095

  1. Disruptive Behaviour of Students in Primary Education and Emotional Intelligence

    Science.gov (United States)

    Esturgo-Deu, M. Estrella; Sala-Roca, Josefina

    2010-01-01

    This study analyses the relation between disruptive behaviours and the emotional abilities of children in primary education. To do this, disruptive behaviour and emotional abilities were evaluated in 1422 pupils aged between 6 and 12 years of age at 11 education centres using EQIjv. No relation was found between disruptive behaviours and age, but…

  2. The Impact of Marital Conflict and Disruption on Children's Health

    Science.gov (United States)

    Houseknecht, Sharon K.; Hango, Darcy W.

    2006-01-01

    This article investigates the effect of inconsistency between parental marital conflict and disruption on children's health. Inconsistent situations arise when minimal marital conflict precedes disruption or when marital conflict is high but there is no disruption. Using data from the National Longitudinal Survey of Youth, two alternative…

  3. [Small intestine bacterial overgrowth].

    Science.gov (United States)

    Leung Ki, E L; Roduit, J; Delarive, J; Guyot, J; Michetti, P; Dorta, G

    2010-01-27

    Small intestine bacterial overgrowth (SIBO) is a condition characterised by nutrient malabsorption and excessive bacteria in the small intestine. It typically presents with diarrhea, flatulence and a syndrome of malabsorption (steatorrhea, macrocytic anemia). However, it may be asymptomatic in the eldery. A high index of suspicion is necessary in order to differentiate SIBO from other similar presenting disorders such as coeliac disease, lactose intolerance or the irritable bowel syndrome. A search for predisposing factor is thus necessary. These factors may be anatomical (stenosis, blind loop), or functional (intestinal hypomotility, achlorydria). The hydrogen breath test is the most frequently used diagnostic test although it lacks standardisation. The treatment of SIBO consists of eliminating predisposing factors and broad-spectrum antibiotic therapy. PMID:20214190

  4. Studying bacterial multispecies biofilms

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Sørensen, Søren Johannes; Burmølle, Mette

    2016-01-01

    The high prevalence and significance of multispecies biofilms have now been demonstrated in various bacterial habitats with medical, industrial, and ecological relevance. It is highly evident that several species of bacteria coexist and interact in biofilms, which highlights the need for evaluating...... the approaches used to study these complex communities. This review focuses on the establishment of multispecies biofilms in vitro, interspecies interactions in microhabitats, and how to select communities for evaluation. Studies have used different experimental approaches; here we evaluate the benefits...... and drawbacks of varying the degree of complexity. This review aims to facilitate multispecies biofilm research in order to expand the current limited knowledge on interspecies interactions. Recent technological advances have enabled total diversity analysis of highly complex and diverse microbial communities...

  5. Bacterial proteases and virulence

    DEFF Research Database (Denmark)

    Frees, Dorte; Brøndsted, Lone; Ingmer, Hanne

    2013-01-01

    Bacterial pathogens rely on proteolysis for variety of purposes during the infection process. In the cytosol, the main proteolytic players are the conserved Clp and Lon proteases that directly contribute to virulence through the timely degradation of virulence regulators and indirectly by providing...... tolerance to adverse conditions such as those experienced in the host. In the membrane, HtrA performs similar functions whereas the extracellular proteases, in close contact with host components, pave the way for spreading infections by degrading host matrix components or interfering with host cell...... signalling to short-circuit host cell processes. Common to both intra- and extracellular proteases is the tight control of their proteolytic activities. In general, substrate recognition by the intracellular proteases is highly selective which is, in part, attributed to the chaperone activity associated...

  6. A New Criterion for Disruption Prediction on HL-2A

    Institute of Scientific and Technical Information of China (English)

    YANG Qing-Wei; JI Xiao-Quan; DING Xuan-Tong; HL-2A team; ZHOU Hang-Yu; FENG Bei-Bin; LIU Yi; PAN Yu-Dong; LI Wei; DUAN Xu-Ru; CHEN Wei; CUI Zheng-Ying

    2006-01-01

    @@ A new criterion has been proposed to predict the major disruptions caused by tearing mode instabilities. According to the HL-2A experimental results, the statistical analyses are employed to investigate the relationships between MHD activities and the plasma disruptions. Two kinds of the tearing mode activities can finally cause the disruption on HL-2A operations. By introducing a new parameter, i.e. an integral of poloidal magnetic field over time, as the criterion of disruption precursor, almost all of the disruptions can be predicted.

  7. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten;

    2010-01-01

    in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by tyrosine......Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... and highlighted their importance in bacterial physiology. Having no orthologues in Eukarya, BY-kinases are receiving a growing attention from the biomedical field, since they represent a particularly promising target for anti-bacterial drug design....

  8. Molecular approaches for bacterial azoreductases

    Directory of Open Access Journals (Sweden)

    Montira Leelakriangsak

    2013-12-01

    Full Text Available Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N- in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study bacterial azoreductases. The construction of the recombinant protein by cloning and the overexpression of azoreductase is described. The mechanisms and function of bacterial azoreductases can be studied by other molecular techniques discussed in this review, such as RT-PCR, southern blot analysis, western blot analysis, zymography, and muta-genesis in order to understand bacterial azoreductase properties, function and application. In addition, understanding the regulation of azoreductase gene expression will lead to the systematic use of gene manipulation in bacterial strains for new strategies in future waste remediation technologies.

  9. Tidal disruption events from supermassive black hole binaries

    CERN Document Server

    Coughlin, Eric R; Nixon, Chris; Begelman, Mitchell C

    2016-01-01

    We investigate the pre-disruption gravitational dynamics and post-disruption hydrodynamics of the tidal disruption of stars by supermassive black hole (SMBH) binaries. We focus on binaries with relatively low mass primaries ($10^6M_{\\odot}$), moderate mass ratios, and separations with reasonably long gravitational wave inspiral times (tens of Myr). First, we generate a large ensemble (between 1 and 10 million) of restricted three-body integrations to quantify the statistical properties of tidal disruptions by circular SMBH binaries of initially-unbound stars. Compared to the reference case of a disruption by a single SMBH, the binary potential induces significant variance into the specific energy and angular momentum of the star at the point of disruption. Second, we use Newtonian numerical hydrodynamics to study the detailed evolution of the fallback debris from 120 disruptions randomly selected from the three-body ensemble (excluding only the most deeply penetrating encounters). We find that the overall mor...

  10. Abundance anomalies in tidal disruption events

    Science.gov (United States)

    Kochanek, C. S.

    2016-05-01

    The ˜10 per cent of tidal disruption events (TDEs) due to stars more massive than M* ≳ M⊙ should show abundance anomalies due to stellar evolution in helium, carbon and nitrogen, but not oxygen. Helium is always enhanced, but only by up to ˜25 per cent on average because it becomes inaccessible once it is sequestered in the high-density core as the star leaves the main sequence. However, portions of the debris associated with the disrupted core of a main-sequence star can be enhanced in helium by factors of 2-3 for debris at a common orbital period. These helium abundance variations may be a contributor to the observed diversity of hydrogen and helium line strengths in TDEs. A still more striking anomaly is the rapid enhancement of nitrogen and the depletion of carbon due to the CNO cycle - stars with M* ≳ M⊙ quickly show an increase in their average N/C ratio by factors of 3-10. Because low-mass stars evolve slowly and high-mass stars are rare, TDEs showing high N/C will almost all be due to ˜1-2 M⊙ stars disrupted on the main sequence. Like helium, portions of the debris will show still larger changes in C and N, and the anomalies decline as the star leaves the main sequence. The enhanced [N/C] abundance ratio of these TDEs provides the first natural explanation for the rare, nitrogen-rich quasars and may also explain the strong nitrogen emission seen in ultraviolet spectra of ASASSN-14li.

  11. Disruption of Four Kinesin Genes in Dictyostelium

    Directory of Open Access Journals (Sweden)

    Soga Ikko

    2008-04-01

    Full Text Available Abstract Background Kinesin and dynein are the two families of microtubule-based motors that drive much of the intracellular movements in eukaryotic cells. Using a gene knockout strategy, we address here the individual function(s of four of the 13 kinesin proteins in Dictyostelium. The goal of our ongoing project is to establish a minimal motility proteome for this basal eukaryote, enabling us to contrast motor functions here with the often far more elaborate motor families in the metazoans. Results We performed individual disruptions of the kinesin genes, kif4, kif8, kif10, and kif11. None of the motors encoded by these genes are essential for development or viability of Dictyostelium. Removal of Kif4 (kinesin-7; CENP-E family significantly impairs the rate of cell growth and, when combined with a previously characterized dynein inhibition, results in dramatic defects in mitotic spindle assembly. Kif8 (kinesin-4; chromokinesin family and Kif10 (kinesin-8; Kip3 family appear to cooperate with dynein to organize the interphase radial microtubule array. Conclusion The results reported here extend the number of kinesin gene disruptions in Dictyostelium, to now total 10, among the 13 isoforms. None of these motors, individually, are required for short-term viability. In contrast, homologs of at least six of the 10 kinesins are considered essential in humans. Our work underscores the functional redundancy of motor isoforms in basal organisms while highlighting motor specificity in more complex metazoans. Since motor disruption in Dictyostelium can readily be combined with other motility insults and stresses, this organism offers an excellent system to investigate functional interactions among the kinesin motor family.

  12. Pheromone disruption of Argentine ant trail integrity

    Science.gov (United States)

    Suckling, D.M.; Peck, R.W.; Manning, L.M.; Stringer, L.D.; Cappadonna, J.; El-Sayed, A. M.

    2008-01-01

    Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation, with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m2) to 1- and 4-m2 plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level impacts can be expected. ?? 2008 Springer Science+Business Media, LLC.

  13. Criteria for endocrine disrupters: report from the Danish centre on Endocrine Disrupters (CEHOS)

    DEFF Research Database (Denmark)

    Holbech, Henrik; Bjerregaard, Poul; Hass, Ulla;

    The aim of this session is to give a presentation of the report (both ENV and HH) on criteria carried out by the Danish Centre on Endocrine Disrupters (CEHOS) as a project contracted by the Danish Environmental Protection Agency. CEHOS is an interdisciplinary scientific network without walls...... and the main purpose of the Centre is to build and gather new knowledge on endocrine disrupters (EDs) with focus on information needed for the preventive work of the regulatory authorities. The aim of the report was to propose scientific criteria for the identification of ED substances of concern for human...

  14. Coherent photon-photon processes in disruptive and non-disruptive relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Using an impact parameter formulation, differential probability distributions and cross sections for the production of lepton pairs via the photon-photon mechanism are calculated for relativistic heavy-ion collisions. The characteristic features of lepton pair production in disruptive as well as in non-disruptive A-A collisions are studied. Cross sections can be large, the very low k perpendicularto -values of the pairs will help to distinguish these pairs from the ones originating from other sources like Drell-Yan or thermal production. (orig.)

  15. Traumatic ureteropelvic disruption in the child

    International Nuclear Information System (INIS)

    Traumatic disruption of the ureter from the renal pelvis is a rare injury because the ureteropelvic junction is situated deep in the retroperitoneum and is thus protected by the spine and paraspinal muscles. The mechanism for this injury is thought to be the stretching of the proximal ureter by sudden extreme hyperextension of the trunk. As a non-fatal injury, this occurs only in the child because of the greater elasticity and mobility of the young skeleton. At The Children's Hospital we have seen 3 cases of avulsion of the ureter from the pelvis following blunt trauma. (orig.)

  16. Amphibians as model to study endocrine disrupters.

    Science.gov (United States)

    Kloas, Werner; Lutz, Ilka

    2006-10-13

    Environmental compounds can interfere with endocrine systems of wildlife and humans. These so-called endocrine disrupters (ED) are known to affect reproductive biology and thyroid system. The classical model species for these endocrine systems are amphibians and therefore they can serve as sentinels for detection of the modes of action (MOAs) of ED. Recently, amphibians are being reviewed as suitable models to assess (anti)estrogenic and (anti)androgenic MOAs influencing reproductive biology as well as (anti)thyroidal MOAs interfering with the thyroid system. The development of targeted bioassays in combination with adequate chemical analyses is the prerequisite for a concise risk assessment of ED.

  17. Multimedia data mining and analytics disruptive innovation

    CERN Document Server

    Baughman, Aaron; Pan, Jia-Yu; Petrushin, Valery A

    2015-01-01

    This authoritative text/reference provides fresh insights into the cutting edge of multimedia data mining, reflecting how the research focus has shifted towards networked social communities, mobile devices and sensors. Presenting a detailed exploration into the progression of the field, the book describes how the history of multimedia data processing can be viewed as a sequence of disruptive innovations. Across the chapters, the discussion covers the practical frameworks, libraries, and open source software that enable the development of ground-breaking research into practical applications.

  18. Both msa Genes in Renibacterium salmoninarum Are Needed for Full Virulence in Bacterial Kidney Disease

    OpenAIRE

    Coady, Alison M; Murray, Anthony L.; Elliott, Diane G.; Linda D Rhodes

    2006-01-01

    Renibacterium salmoninarum, a gram-positive diplococcobacillus that causes bacterial kidney disease among salmon and trout, has two chromosomal loci encoding the major soluble antigen (msa) gene. Because the MSA protein is widely suspected to be an important virulence factor, we used insertion-duplication mutagenesis to generate disruptions of either the msa1 or msa2 gene. Surprisingly, expression of MSA protein in broth cultures appeared unaffected. However, the virulence of either mutant in...

  19. Commensal bacterial internalization by epithelial cells: An alternative portal for gut leakiness

    OpenAIRE

    Yu, Linda Chia-Hui

    2015-01-01

    Co-existing paracellular and transcellular barrier defect in intestinal epithelium was documented in inflammatory bowel disease, celiac disease, and intestinal obstruction. Mechanisms regarding tight junction disruption have been extensively studied; however, limited progress has been made in research on bacterial transcytosis. Densely packed brush border (BB), with cholesterol-based lipid rafts in the intermicrovillous membrane invagination, serves as an ultrastructural barrier to prevent di...

  20. Transition state analogs of 5'-methylthioadenosine nucleosidase disrupt quorum sensing.

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, J.; Crowder, T; Rinaldo-Matthis, A; Ho, M; Almo, S; Schramm, V

    2009-01-01

    5'-Methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) is a bacterial enzyme involved in S-adenosylmethionine-related quorum sensing pathways that induce bacterial pathogenesis factors. Transition state analogs MT-DADMe-Immucillin-A, EtT-DADMe-Immucillin-A and BuT-DADMe-Immucillin-A are slow-onset, tight-binding inhibitors of Vibrio cholerae MTAN (VcMTAN), with equilibrium dissociation constants of 73, 70 and 208 pM, respectively. Structural analysis of VcMTAN with BuT-DADMe-Immucillin-A revealed interactions contributing to the high affinity. We found that in V. cholerae cells, these compounds are potent MTAN inhibitors with IC50 values of 27, 31 and 6 nM for MT-, EtT- and BuT-DADMe-Immucillin-A, respectively; the compounds disrupt autoinducer production in a dose-dependent manner without affecting growth. MT- and BuT-DADMe-Immucillin-A also inhibited autoinducer-2 production in enterohemorrhagic Escherichia coli O157:H7 with IC{sub 50} values of 600 and 125 nM, respectively. BuT-DADMe-Immucillin-A inhibition of autoinducer-2 production in both strains persisted for several generations and caused reduction in biofilm formation. These results support MTAN's role in quorum sensing and its potential as a target for bacterial anti-infective drug design.

  1. Positioning of bacterial chemoreceptors.

    Science.gov (United States)

    Jones, Christopher W; Armitage, Judith P

    2015-05-01

    For optimum growth, bacteria must adapt to their environment, and one way that many species do this is by moving towards favourable conditions. To do so requires mechanisms to both physically drive movement and provide directionality to this movement. The pathways that control this directionality comprise chemoreceptors, which, along with an adaptor protein (CheW) and kinase (CheA), form large hexagonal arrays. These arrays can be formed around transmembrane receptors, resulting in arrays embedded in the inner membrane, or they can comprise soluble receptors, forming arrays in the cytoplasm. Across bacterial species, chemoreceptor arrays (both transmembrane and soluble) are localised to a variety of positions within the cell; some species with multiple arrays demonstrate this variety within individual cells. In many cases, the positioning pattern of the arrays is linked to the need for segregation of arrays between daughter cells on division, ensuring the production of chemotactically competent progeny. Multiple mechanisms have evolved to drive this segregation, including stochastic self-assembly, cellular landmarks, and the utilisation of ParA homologues. The variety of mechanisms highlights the importance of chemotaxis to motile species.

  2. Evolution of Bacterial Suicide

    Science.gov (United States)

    Tchernookov, Martin; Nemenman, Ilya

    2013-03-01

    While active, controlled cellular suicide (autolysis) in bacteria is commonly observed, it has been hard to argue that autolysis can be beneficial to an individual who commits it. We propose a theoretical model that predicts that bacterial autolysis is evolutionarily advantageous to an individualand would fixate in physically structured environments for stationary phase colonies. We perform spatially resolved agent-based simulations of the model, which predict that lower mixing in the environment results in fixation of a higher autolysis rate from a single mutated cell, regardless of the colony's genetic diversity. We argue that quorum sensing will fixate as well, even if initially rare, if it is coupled to controlling the autolysis rate. The model does not predict a strong additional competitive advantage for cells where autolysis is controlled by quorum sensing systems that distinguish self from nonself. These predictions are broadly supported by recent experimental results in B. subtilisand S. pneumoniae. Research partially supported by the James S McDonnell Foundation grant No. 220020321 and by HFSP grant No. RGY0084/2011.

  3. Electromagnetism of Bacterial Growth

    Science.gov (United States)

    Ainiwaer, Ailiyasi

    2011-10-01

    There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.

  4. Abundance Anomalies In Tidal Disruption Events

    CERN Document Server

    Kochanek, C S

    2015-01-01

    The ~10% of tidal disruption events (TDEs) due to stars more massive than the Sun should show abundance anomalies due to stellar evolution in helium, carbon and nitrogen, but not oxygen. Helium is always enhanced, but only by up to ~25% on average because it becomes inaccessible once it is sequestered in the high density core as the star leaves the main sequence. However, portions of the debris associated with the disrupted core of a main sequence star can be enhanced in helium by factors of 2-3 for debris at a common orbital period. These helium abundance variations may be a contributor to the observed diversity of hydrogen and helium line strengths in TDEs. A still more striking anomaly is the rapid enhancement of nitrogen and the depletion of carbon due to the CNO cycle -- stars more massive than the Sun quickly show an increase in their average N/C ratio by factors of 3-10. Because low mass stars evolve slowly and high mass stars are rare, TDEs showing high N/C will almost all be due to 1-2Msun stars disr...

  5. Disruptive mood dysregulation disorder: current insights

    Directory of Open Access Journals (Sweden)

    Baweja R

    2016-08-01

    Full Text Available Raman Baweja, Susan D Mayes, Usman Hameed, James G Waxmonsky Department of Psychiatry, Penn State University College of Medicine, Hershey, PA, USA Abstract: Disruptive mood dysregulation disorder (DMDD was introduced as a new diagnostic entity under the category of depressive disorders in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5. It was included in DSM-5 primarily to address concerns about the misdiagnosis and consequent overtreatment of bipolar disorder in children and adolescents. DMDD does provide a home for a large percentage of referred children with severe persistent irritability that did not fit well into any DSM, Fourth Edition (DSM-IV diagnostic category. However, it has been a controversial addition to the DSM-5 due to lack of published validity studies, leading to questions about its validity as a distinct disorder. In this article, the authors discuss the diagnostic criteria, assessment, epidemiology, criticism of the diagnosis, and pathophysiology, as well as treatment and future directions for DMDD. They also review the literature on severe mood dysregulation, as described by the National Institute of Mental Health, as the scientific support for DMDD is based primarily on studies of severe mood dysregulation. Keywords: disruptive mood dysregulation disorder, persistent irritability, temper outbursts 

  6. Features, Events, and Processes: Disruptive Events

    Energy Technology Data Exchange (ETDEWEB)

    P. Sanchez

    2004-11-08

    The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the disruptive events features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for license application (TSPA-LA). A screening decision, either ''Included'' or ''Excluded,'' is given for each FEP, along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), and (f) [DIRS 156605]. The FEPs addressed in this report deal with both seismic and igneous disruptive events, such as fault displacements through the repository and an igneous intrusion into the repository. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded). Previous versions of this report were developed to support the total system performance assessments (TSPA) for various prior repository designs. This revision addresses the repository design for the license application (LA).

  7. Transcriptional regulation of the outer membrane porin gene ompW reveals its physiological role during the transition from the aerobic to the anaerobic lifestyle of Escherichia coli

    Directory of Open Access Journals (Sweden)

    Minfeng eXiao

    2016-05-01

    Full Text Available Understanding bacterial physiology relies on elucidating the regulatory mechanisms and cellular functions of those differentially expressed genes in response to environmental changes. A widespread Gram-negative bacterial outer membrane protein OmpW has been implicated in the adaptation to stresses in various species. It is recently found to be present in the regulon of the global anaerobic transcription factor FNR and ArcA in E. coli. However, little is known about the physiological implications of this regulatory disposition. In this study, we demonstrate that transcription of ompW is indeed mediated by a series of global regulators involved in the anaerobiosis of E. coli. We show that FNR can both activate and repress the expression of ompW through its direct binding to two distinctive sites, -81.5 and -126.5 bp respectively, on ompW promoter. ArcA also participates in repression of ompW under anaerobic condition, but in an FNR dependent manner. Additionally, ompW is also subject to the regulation by CRP and NarL which senses the availability and types of carbon sources and respiration electron acceptors in the environment respectively, implying a role of OmpW in the carbon and energy metabolism of E. coli during its anaerobic adaptation. Molecular docking reveals that OmpW can bind fumarate, an alternative electron acceptor in anaerobic respiration, with sufficient affinity. Moreover, supplement of fumarate or succinate which belongs to the C4-dicarboxylates family of metabolite, to E. coli culture rescues OmpW-mediated colicin S4 killing. Taken together, we propose that OmpW is involved in anaerobic carbon and energy metabolism to mediate the transition from aerobic to anaerobic lifestyle in E. coli.

  8. Disruptive Conduct: The Impact of Disruptive Technologies on Social Relations in Higher Education

    Science.gov (United States)

    Flavin, Michael

    2016-01-01

    Higher education institutions (HEIs) have invested significantly in digital technologies for learning and teaching. However, technologies provided by HEIs have not been universally successful in terms of adoption and usage. Meanwhile, both students and lecturers use disruptive technologies to support learning and teaching. This article examines…

  9. Disrupting Law School: How Disruptive Innovation Will Revolutionize the Legal World

    Science.gov (United States)

    Pistone, Michele R.; Horn, Michael B.

    2016-01-01

    Facing dramatic declines in enrollment, revenue, and student quality at the same time that their cost structure continues to rise and public support has waned, law schools are in crisis. A key driver of the crisis is shrinking employment opportunities for recent graduates, which stem in part from the disruption of the traditional business model…

  10. A Molecularly Complete Planar Bacterial Outer Membrane Platform.

    Science.gov (United States)

    Hsia, Chih-Yun; Chen, Linxiao; Singh, Rohit R; DeLisa, Matthew P; Daniel, Susan

    2016-01-01

    The bacterial outer membrane (OM) is a barrier containing membrane proteins and liposaccharides that fulfill crucial functions for Gram-negative bacteria. With the advent of drug-resistant bacteria, it is necessary to understand the functional role of this membrane and its constituents to enable novel drug designs. Here we report a simple method to form an OM-like supported bilayer (OM-SB), which incorporates native lipids and membrane proteins of gram-negative bacteria from outer membrane vesicles (OMVs). We characterize the formation of OM-SBs using quartz crystal microbalance with dissipation (QCM-D) and fluorescence microscopy. We show that the orientation of proteins in the OM-SB matches the native bacterial membrane, preserving the characteristic asymmetry of these membranes. As a demonstration of the utility of the OM-SB platform, we quantitatively measure antibiotic interactions between OM-SBs and polymyxin B, a cationic peptide used to treat Gram-negative infections. This data enriches understanding of the antibacterial mechanism of polymyxin B, including disruption kinetics and changes in membrane mechanical properties. Combining OM-SBs with microfluidics will enable higher throughput screening of antibiotics. With a broader view, we envision that a molecularly complete membrane-scaffold could be useful for cell-free applications employing engineered membrane proteins in bacterial membranes for myriad technological purposes. PMID:27600663

  11. Bacterial Communities: Interactions to Scale

    Science.gov (United States)

    Stubbendieck, Reed M.; Vargas-Bautista, Carol; Straight, Paul D.

    2016-01-01

    In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities. PMID:27551280

  12. Bacterial Communities: Interactions to Scale

    Directory of Open Access Journals (Sweden)

    Reed M. Stubbendieck

    2016-08-01

    Full Text Available In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities.

  13. Meningitis bacteriana Bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Ana Teresa Alvarado Guevara

    2006-03-01

    causales son virales lo cual conlleva a las diferentes sub-clasificaciones. También en ciertos casos puede ser ocasionada por hongos, bacterias atípicas, micobacterias y parásitos.In Costa Rica the bacterial meningitis had turn into a high-priority subject in which to monitoring epidemiologist. It had been talked about in the last months, to dice an increase in the attention is published of this subject, due to this phenomenon it becomes necessary to make a revision of topic. Meningitis is an inflammation of leptomeninges and colonization of the subarachnoid cerebrospinal fluid (LCR due to different agents, which produces meningeal symptoms (ex. migraine, neck rigidity, and photophobia and pleocytosis in LCR. De pending on the variables to take into account is possible to group it in different classifications, taking into account the time of evolution are possible to be divided in acute or chronic, to first with few hours or days of beginning of the symptoms, whereas the chronicle also presents a silence course but of the disease of approximately 4 weeks of instauration. There is a difference according to its etiologic agent; they can be infectious and non-infectious. Examples of common non-infectious causes include medications (ex, nonsteroidal anti-inflammatory drugs, and antibiotics and carcinomatosis. A classification exists as well according to the causal agent. The acute bacterial meningitis remarks a bacterial origin of the syndrome, which characterizes by the by an acute onset of meningeal symptoms and neutrophilic pleocytosis. Each one of the bacteriological agents, parasitic or fungus finishes by characterizing the different presentations of the clinical features (ex, meningocóccica meningitis, Cryptococcus meningitis. Finally, there is also the aseptic meningitis, denominated in this form because it’s nonpyogenic cellular response caused by many types of agents. The patients show an acute beginning of symptoms, fever and lymphocytic pleocytosis. After

  14. SIMULATING THE SUPPLY DISRUPTION FOR THE COORDINATED SUPPLY CHAIN

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    There are many disruptive accidents in the supply chain operations system and achieving the coordination of supply chain is main objective for supply chain research. While disruptive accidents have increasingly influenced the coordinated operation of the supply chain, existing research literature on the supply chain coordination is setting in a stationary environment. The answer for how the disruptive accidents affect the coordinated supply chain is given in this paper. Based on the benchmark supply chain which is coordinated by the negative incentive mechanism, we study the impacts of supply disruption on the supply chain system by using simulation approach in which two different distribution function of random variable are used to express the supply disruption. Comparison between these two simulation results and possible coordination mechanism under the supply disruption are proposed. From the perspective of supply chain risk management, we provide the inspiration for the manager.

  15. Bacterial Culture of Neonatal Sepsis

    OpenAIRE

    AH Movahedian; R Moniri; Z Mosayebi

    2006-01-01

    Neonatal bacterial sepsis is one of the major cause of morbidity and mortality in neonates. This retrospective study was performed to determine the incidence of bacterial sepsis with focus on Gram negative organisms in neonates admitted at Beheshti Hospital in Kashan, during a 3-yr period, from September 2002 to September 2005. Blood culture was performed on all neonates with risk factors or signs of suggestive sepsis. Blood samples were cultured using brain heart infusion (BHI) broth accordi...

  16. Mast cells in bacterial infections

    OpenAIRE

    Rönnberg, Elin

    2014-01-01

    Mast cells are implicated in immunity towards bacterial infection, but the molecular mechanisms by which mast cells contribute to the host response are only partially understood. Previous studies have examined how mast cells react to purified bacterial cell wall components, such as peptidoglycan and lipopolysaccharide. To investigate how mast cells react to live bacteria we co-cultured mast cells and the gram-positive bacteria Streptococcus equi (S. equi) and Staphylococcus aureus (S. aureus)...

  17. Bacterial Alkaloids Prevent Amoebal Predation.

    Science.gov (United States)

    Klapper, Martin; Götze, Sebastian; Barnett, Robert; Willing, Karsten; Stallforth, Pierre

    2016-07-25

    Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A-D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae. PMID:27294402

  18. Bacterial cellulose/boehmite composites

    International Nuclear Information System (INIS)

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  19. Fish and wildlife species as sentinels of environmental endocrine disruption

    Science.gov (United States)

    Sheffield, S.R.; Matter, J.M.; Rattner, B.A.; Guiney, P.D.; Kendall, Ronald J.; Dickerson, Richard L.; Giesy, John P.; Suk, William P.

    1998-01-01

    This chapter provides an overview of the history and criteria for use of captive and free-ranging fish and wildlife (amphibians, reptiles, birds, and mammals) species as sentinels of potential environmental endocrine disruption. Biochemical, behavioral, physiological, immunological, genetic, reproductive, developmental, and ecological correlates of endocrine disruption in these sentinels are presented and reviewed. In addition, data needs to promote better use of sentinel species in the assessment of endocrine disruption are discussed.

  20. Research progress of the endocrine disrupting activities of polychlorinated biphenyls

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jingming; QIN Zhanfen; CONG Lin; XU Xiaobai

    2004-01-01

    Polychlorinated biphenyls (PCBs) are global persistent organic pollutants. Almost all commercial PCBs mixtures, single PCB congener, and their metabolites possess endocrine disrupting activities. They can disrupt the estrogen/androgen system, thyroid hormone system and other endocrine systems by interfering with the synthesis, transport, storage, metabolism, and feedback regulation of hormones. The newest data related to the endocrine disrupting activities of PCBs and their mechanisms are reviewed and the research perspectives are also discussed.

  1. Universal versus tailored solutions for alleviating disruptive behavior in hospitals

    OpenAIRE

    Berman-Kishony, Talia; Shvarts, Shifra

    2015-01-01

    Background: Disruptive behavior among hospital staff can negatively affect quality of care. Motivated by a standard on disruptive behavior issued by The Joint Commission (LD 3.10), as well as the desire to improve patient care, minimize liability, and improve staff retention, hospitals are setting policies to prevent and resolve disruptive behaviors. However, it is unknown whether uniform conflict management tools are equally effective among different hospital settings. Methods: We surveyed r...

  2. Environmental endocrine disruption: an effects assessment and analysis.

    OpenAIRE

    Crisp, T M; Clegg, E D; Cooper, R. L.; Wood, W. P.; D. G. Anderson; Baetcke, K. P.; Hoffmann, J L; Morrow, M S; Rodier, D J; Schaeffer, J E; Touart, L W; Zeeman, M G; Patel, Y. M.

    1998-01-01

    This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analy...

  3. Disruption of zinc homeostasis in Alzheimer's disease

    Science.gov (United States)

    Robertson, J. D.; Crafford, A. M.; Markesbery, W. R.; Lovell, M. A.

    2002-04-01

    The basic hypothesis being tested is that, in Alzheimer's disease (AD), the delicate balance of brain Zn is disrupted and may play a role in the pathogenesis of neuron degeneration. Micro-PIXE measurements reveal a significant elevation of Zn in senile plaques (SP) in AD brain compared with adjacent neuropil and a significant increase in AD neuropil compared to control neuropil. The observation of elevated Zn in SP is of interest because the amyloid precursor protein contains a Zn binding site that may prevent normal cleavage leading to the generation of a toxic fragment of beta amyloid, the constituent of SP. The potential of using laser-ablation inductively coupled plasma mass spectrometry as a complimentary microprobe technique is also presented.

  4. Assessment of CRBR core disruptive accident energetics

    International Nuclear Information System (INIS)

    The results of an independent assessment of core disruptive accident energetics for the Clinch River Breeder Reactor are presented in this document. This assessment was performed for the Nuclear Regulatory Commission under the direction of the CRBR Program Office within the Office of Nuclear Reactor Regulation. It considered in detail the accident behavior for three accident initiators that are representative of three different classes of events; unprotected loss of flow, unprotected reactivity insertion, and protected loss of heat sink. The primary system's energetics accommodation capability was realistically, yet conservatively, determined in terms of core events. This accommodation capability was found to be equivalent to an isentropic work potential for expansion to one atmosphere of 2550 MJ or a ramp rate of about 200 $/s applied to a classical two-phase disassembly

  5. Collisional and Rotational Disruption of Asteroids

    CERN Document Server

    Walsh, Kevin J; Richardson, Derek C

    2009-01-01

    Asteroids are leftover pieces from the era of planet formation that help us understand conditions in the early Solar System. Unlike larger planetary bodies that were subject to global thermal modification during and subsequent to their formation, these small bodies have kept at least some unmodified primordial material from the solar nebula. However, the structural properties of asteroids have been modified considerably since their formation. Thus, we can find among them a great variety of physical configurations and dynamical histories. In fact, with only a few possible exceptions, all asteroids have been modified or completely disrupted many times during the age of the Solar System. This picture is supported by data from space mission encounters with asteroids that show much diversity of shape, bulk density, surface morphology, and other features. Moreover, the gravitational attraction of these bodies is so small that some physical processes occur in a manner far removed from our common experience on Earth....

  6. Features, Events, and Processes: Disruptive Events

    International Nuclear Information System (INIS)

    The primary purpose of this analysis is to evaluate seismic- and igneous-related features, events, and processes (FEPs). These FEPs represent areas of natural system processes that have the potential to produce disruptive events (DE) that could impact repository performance and are related to the geologic processes of tectonism, structural deformation, seismicity, and igneous activity. Collectively, they are referred to as the DE FEPs. This evaluation determines which of the DE FEPs are excluded from modeling used to support the total system performance assessment for license application (TSPA-LA). The evaluation is based on the data and results presented in supporting analysis reports, model reports, technical information, or corroborative documents that are cited in the individual FEP discussions in Section 6.2 of this analysis report

  7. Disruption of zinc homeostasis in Alzheimer's disease

    International Nuclear Information System (INIS)

    The basic hypothesis being tested is that, in Alzheimer's disease (AD), the delicate balance of brain Zn is disrupted and may play a role in the pathogenesis of neuron degeneration. Micro-PIXE measurements reveal a significant elevation of Zn in senile plaques (SP) in AD brain compared with adjacent neuropil and a significant increase in AD neuropil compared to control neuropil. The observation of elevated Zn in SP is of interest because the amyloid precursor protein contains a Zn binding site that may prevent normal cleavage leading to the generation of a toxic fragment of beta amyloid, the constituent of SP. The potential of using laser-ablation inductively coupled plasma mass spectrometry as a complimentary microprobe technique is also presented

  8. Disrupting neuronal transmission: Mechanism of DBS?

    Directory of Open Access Journals (Sweden)

    Satomi eChiken

    2014-03-01

    Full Text Available Applying high-frequency stimulation to deep brain rain structure, known as deep brain stimulation (DBS, has now been recognized an effective therapeutic option for a wide range of neurological and psychiatric disorders. DBS targeting the basal ganglia thalamo-cortical loop, especially the internal segment of the globus pallidus, subthalamic nucleus and thalamus, has been widely employed as a successful surgical therapy for movement disorders, such as Parkinson’s disease, dystonia and tremor. However, the neurophysiological mechanism underling the action of DBS remains unclear and is still under debate: does DBS inhibit or excite local neuronal elements? In this review, we will examine this question and propose the alternative interpretation: DBS dissociates inputs and outputs, resulting in disruption of abnormal signal transmission.

  9. Features, Events, and Processes: Disruptive Events

    Energy Technology Data Exchange (ETDEWEB)

    J. King

    2004-03-31

    The primary purpose of this analysis is to evaluate seismic- and igneous-related features, events, and processes (FEPs). These FEPs represent areas of natural system processes that have the potential to produce disruptive events (DE) that could impact repository performance and are related to the geologic processes of tectonism, structural deformation, seismicity, and igneous activity. Collectively, they are referred to as the DE FEPs. This evaluation determines which of the DE FEPs are excluded from modeling used to support the total system performance assessment for license application (TSPA-LA). The evaluation is based on the data and results presented in supporting analysis reports, model reports, technical information, or corroborative documents that are cited in the individual FEP discussions in Section 6.2 of this analysis report.

  10. Assessment of CRBR core disruptive accident energetics

    Energy Technology Data Exchange (ETDEWEB)

    Theofanous, T.G.; Bell, C.R.

    1984-03-01

    The results of an independent assessment of core disruptive accident energetics for the Clinch River Breeder Reactor are presented in this document. This assessment was performed for the Nuclear Regulatory Commission under the direction of the CRBR Program Office within the Office of Nuclear Reactor Regulation. It considered in detail the accident behavior for three accident initiators that are representative of three different classes of events; unprotected loss of flow, unprotected reactivity insertion, and protected loss of heat sink. The primary system's energetics accommodation capability was realistically, yet conservatively, determined in terms of core events. This accommodation capability was found to be equivalent to an isentropic work potential for expansion to one atmosphere of 2550 MJ or a ramp rate of about 200 $/s applied to a classical two-phase disassembly.

  11. Endocrine disrupter - estradiol - in Chesapeake Bay tributaries

    Energy Technology Data Exchange (ETDEWEB)

    Dorabawila, Nelum [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States); Gupta, Gian [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States)]. E-mail: gcgupta@umes.edu

    2005-04-11

    Exogenous chemicals that interfere with natural hormonal functions are considered endocrine disrupting chemicals (EDCs). Estradiol (17{beta}-estradiol or E2) is the most potent of all xenoestrogens. Induction of vitellogenin (VTG) production in male fish occurs at E2 concentrations as low as 1 ng l{sup -1}. E2 reaches aquatic systems mainly through sewage and animal waste disposal. Surface water samples from ponds, rivers (Wicomico, Manokin and Pocomoke), sewage treatment plants (STPs), and coastal bays (Assawoman, Monie, Chincoteague, and Tangier Sound - Chesapeake Bay) on the Eastern Shore of Maryland were analyzed for E2 using enzyme linked immuno-sorbent assay (ELISA). E2 concentrations in river waters varied between 1.9 and 6.0 ng l{sup -1}. Highest E2 concentrations in river waters were observed immediately downstream of STPs. E2 concentrations in all the coastal bays tested were 2.3-3.2 ng l{sup -1}.

  12. How to Spot a Disrupted Galactic Satellite

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    Many satellites dwarf galaxies and globular clusters are thought to be orbiting our galaxy, but detecting them can be a tricky business. In particular, satellites can be disrupted by the galactic potential and spread out into streams, making them so diffuse that were unable to spot them in photometric observations.In a recent study, a team of scientists led by John Vickers (Chinese Academy of Sciences) has cleverly worked around this difficulty by searching for groups of stars that have clustered velocities and metallicities differing from the background field.Searching Through StarsRadial velocity and metallicity of LAMOST stars near the physical location of Lamost 1. Circles are stars within 1.5 of the target location, small dots are stars within 5. [Vickers et al. 2016]The team trawled the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) catalog, which contains spectroscopic information for 2.5 million stars. Vickers and collaborators first hunted for stars that shared an approximate physical location and had similar velocities (because the stars of a satellite will maintain similar velocities even after the satellite is disrupted). Next, they discarded any of these clumps that didnt also share a similar metallicity.Vickers and collaborators then compared the resulting set of 21 candidate streams to catalogs of known globular clusters, open clusters, and nearby galaxies. Three of the candidate clumps, clustered in a 3 area on the sky, do not correspond to any known objects. The authors postulate that these are all part of a disrupted satellite, which they dub Lamost 1.Characterizing a Former ClusterFitting the spectroscopic data for the member stars, the authors are able to estimate a number of characteristics of Lamost 1, with the best fit implying an age of 11 Gyr, a total mass of about 20,000 solar masses, and a distance from us of about 8,500 light-years.Based on the stellar motions, the authors believe that the clump is on an eccentric

  13. A bright year for tidal disruptions

    Science.gov (United States)

    Metzger, Brian D.; Stone, Nicholas C.

    2016-09-01

    When a star is tidally disrupted by a supermassive black hole (SMBH), roughly half of its mass falls back to the SMBH at super-Eddington rates. As this gas is tenuously gravitationally bound and unable to cool radiatively, only a small fraction fin ≪ 1 may accrete, with the majority instead becoming unbound in an outflow of velocity ˜104 km s-1. The outflow spreads laterally as it expands to large radii, encasing the SMBH and blocking the inner disc's EUV/X-ray radiation, which becomes trapped in a radiation-dominated nebula. Ionizing nebular radiation heats the inner edge of the ejecta, converting the emission to optical/near-UV wavelengths where photons more readily escape due to the lower opacity. This can explain the unexpectedly low and temporally constant effective temperatures of optically discovered tidal disruption event (TDE) flares. For high-mass SMBHs, M• ≳ 107 M⊙, the ejecta can become fully ionized at an earlier stage, or for a wider range of viewing angles, producing a TDE flare accompanied by thermal X-ray emission. The peak optical luminosity is suppressed as the result of adiabatic losses in the inner disc wind when M• ≪ 107 M⊙, possibly contributing to the unexpected dearth of optical TDEs in galaxies with low-mass SMBHs. In the classical picture, where fin ≈ 1, TDEs de-spin supermassive SMBHs and cap their maximum spins well below theoretical accretion physics limits. This cap is relaxed in our model, and existing Fe Kα spin measurements provide preliminary evidence that fin < 1.

  14. Exploring the relationship between retrieval disruption from collaboration and recall.

    Science.gov (United States)

    Barber, Sarah J; Rajaram, Suparna

    2011-07-01

    When people recall together in a collaborative group they recall less than their potential. This phenomenon of collaborative inhibition is explained in terms of retrieval disruption. However, collaborative recall also re-exposes individuals to items recalled by others that they themselves might otherwise have forgotten. This re-exposure produces post-collaborative benefits in individual recall. The current study examined whether reduced retrieval disruption during group recall is related not only to less collaborative inhibition, but also to greater post-collaborative recall benefits. To test this we devised a paradigm to calculate the extent to which each individual experienced retrieval disruption during group recall. We also included two types of collaborative groups, one of which was expected to experience greater retrieval disruption than the other. Results suggest that the relationship between retrieval disruption and recall performance depends on the level at which retrieval disruption is measured. When retrieval disruption was assessed at the individual level, then minimising retrieval disruption was associated with higher recall (i.e., less collaborative inhibition and greater post-collaborative individual recall). However, when retrieval disruption was assessed at the group level there was no relationship with recall. Furthermore, the findings from this design suggest a role of cross-cueing in modulating group recall levels.

  15. DISRUPTION MANAGEMENT FOR SUPPLY CHAIN COORDINATION WITH EXPONENTIAL DEMAND FUNCTION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The coordination problem of a supply chain comprising one supplier and one retailer under market demand disruption is studied in this article. A novel exponential demand function is adopted, and the penalty cost is introduced explicitly to capture the deviation production cost caused by the market demand disruption. The optimal strategies are obtained for different disruption scale under the centralized mode. For the decentralized mode, it is proved that the supply chain can be fully coordinated by adjusting the price discount policy appropriately when disruption occurs. Furthermore, the authors point out that similar results can be established for more general demand functions that represent different market circumstances if certain assumptions are satisfied.

  16. Disruptions in ITER and strategies for their control and mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Lehnen, M., E-mail: michael.lehnen@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Aleynikova, K.; Aleynikov, P.B.; Campbell, D.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Drewelow, P. [Max-Planck-Institut für Plasmaphysik, Greifswald branch, EURATOM Ass., D-17491 Greifswald (Germany); Eidietis, N.W. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Gasparyan, Yu. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, Moscow 115409 (Russian Federation); Granetz, R.S. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States); Gribov, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Hartmann, N. [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research—Plasma Physics, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Jülich (Germany); Hollmann, E.M. [University of California-San Diego, La Jolla, CA 92093 (United States); Izzo, V.A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Jachmich, S. [Laboratory for Plasma Physics, ERM/KMS, Association EURATOM – Belgian State, B-1000 Brussels (Belgium); Kim, S.-H.; Kočan, M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Koslowski, H.R. [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research—Plasma Physics, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Jülich (Germany); Kovalenko, D. [SRC RF TRINITI, ul. Pushkovykh, vladenie 12, Troitsk, Moscow 142190 (Russian Federation); Kruezi, U. [CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); and others

    2015-08-15

    The thermal and electromagnetic loads related to disruptions in ITER are substantial and require careful design of tokamak components to ensure they reach the projected lifetime and to ensure that safety relevant components fulfil their function for the worst foreseen scenarios. The disruption load specifications are the basis for the design process of components like the full-W divertor, the blanket modules and the vacuum vessel and will set the boundary conditions for ITER operations. This paper will give a brief overview on the disruption loads and mitigation strategies for ITER and will discuss the physics basis which is continuously refined through the current disruption R&D programs.

  17. Understanding the Dispersion and Assembly of Bacterial Cellulose in Organic Solvents.

    Science.gov (United States)

    Ferguson, Auren; Khan, Umar; Walsh, Melissa; Lee, Koon-Yang; Bismarck, Alexander; Shaffer, Milo S P; Coleman, Jonathan N; Bergin, Shane D

    2016-05-01

    The constituent nanofibrils of bacterial cellulose are of interest to many researchers because of their purity and excellent mechanical properties. Mechanisms to disrupt the network structure of bacterial cellulose (BC) to isolate bacterial cellulose nanofibrils (BCN) are limited. This work focuses on liquid-phase dispersions of BCN in a range of organic solvents. It builds on work to disperse similarly intractable nanomaterials, such as single-walled carbon nanotubes, where optimum dispersion is seen for solvents whose surface energies are close to the surface energy of the nanomaterial; bacterial cellulose is shown to disperse in a similar fashion. Inverse gas chromatography was used to determine the surface energy of bacterial cellulose, under relevant conditions, by quantifying the surface heterogeneity of the material as a function of coverage. Films of pure BCN were prepared from dispersions in a range of solvents; the extent of BCN exfoliation is shown to have a strong effect on the mechanical properties of BC films and to fit models based on the volumetric density of nanofibril junctions. Such control offers new routes to producing robust cellulose films of bacterial cellulose nanofibrils. PMID:27007744

  18. Disruption calling: Strategic implications of disruptive innovations on the Canadian telecommunications industry

    OpenAIRE

    Mendoza, Michael

    2006-01-01

    Disruptive forces are impacting the telecommunications industry. In the near-term, these innovations will spur competition from alternative network providers seeking to provide equivalent services at a lower cost and a lower price. Medium term threats include service, content and application providers that seek to relegate telecom firms to being “pipe providers”. Longer term implications come from the fact that service and content providers will begin to reach through the network an...

  19. The Human Vaginal Bacterial Biota and Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Sujatha Srinivasan

    2008-01-01

    Full Text Available The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV. PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition.

  20. Disruption of the Gut Microbiome: Clostridium difficile Infection and the Threat of Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Priscilla A. Johanesen

    2015-12-01

    Full Text Available Clostridium difficile is well recognized as the leading cause of antibiotic-associated diarrhea, having a significant impact in both health-care and community settings. Central to predisposition to C. difficile infection is disruption of the gut microbiome by antibiotics. Being a Gram-positive anaerobe, C. difficile is intrinsically resistant to a number of antibiotics. Mobile elements encoding antibiotic resistance determinants have also been characterized in this pathogen. While resistance to antibiotics currently used to treat C. difficile infection has not yet been detected, it may be only a matter of time before this occurs, as has been seen with other bacterial pathogens. This review will discuss C. difficile disease pathogenesis, the impact of antibiotic use on inducing disease susceptibility, and the role of antibiotic resistance and mobile elements in C. difficile epidemiology.

  1. Bacterial tactic responses.

    Science.gov (United States)

    Armitage, J P

    1999-01-01

    Many, if not most, bacterial species swim. The synthesis and operation of the flagellum, the most complex organelle of a bacterium, takes a significant percentage of cellular energy, particularly in the nutrient limited environments in which many motile species are found. It is obvious that motility accords cells a survival advantage over non-motile mutants under normal, poorly mixed conditions and is an important determinant in the development of many associations between bacteria and other organisms, whether as pathogens or symbionts and in colonization of niches and the development of biofilms. This survival advantage is the result of sensory control of swimming behaviour. Although too small to sense a gradient along the length of the cell, and unable to swim great distances because of buffetting by Brownian motion and the curvature resulting from a rotating flagellum, bacteria can bias their random swimming direction towards a more favourable environment. The favourable environment will vary from species to species and there is now evidence that in many species this can change depending on the current physiological growth state of the cell. In general, bacteria sense changes in a range of nutrients and toxins, compounds altering electron transport, acceptors or donors into the electron transport chain, pH, temperature and even the magnetic field of the Earth. The sensory signals are balanced, and may be balanced with other sensory pathways such as quorum sensing, to identify the optimum current environment. The central sensory pathway in this process is common to most bacteria and most effectors. The environmental change is sensed by a sensory protein. In most species examined this is a transmembrane protein, sensing the external environment, but there is increasing evidence for additional cytoplasmic receptors in many species. All receptors, whether sensing sugars, amino acids or oxygen, share a cytoplasmic signalling domain that controls the activity of a

  2. New Treatments for Bacterial Keratitis

    Directory of Open Access Journals (Sweden)

    Raymond L. M. Wong

    2012-01-01

    Full Text Available Purpose. To review the newer treatments for bacterial keratitis. Data Sources. PubMed literature search up to April 2012. Study Selection. Key words used for literature search: “infectious keratitis”, “microbial keratitis”, “infective keratitis”, “new treatments for infectious keratitis”, “fourth generation fluoroquinolones”, “moxifloxacin”, “gatifloxacin”, “collagen cross-linking”, and “photodynamic therapy”. Data Extraction. Over 2400 articles were retrieved. Large scale studies or publications at more recent dates were selected. Data Synthesis. Broad spectrum antibiotics have been the main stay of treatment for bacterial keratitis but with the emergence of bacterial resistance; there is a need for newer antimicrobial agents and treatment methods. Fourth-generation fluoroquinolones and corneal collagen cross-linking are amongst the new treatments. In vitro studies and prospective clinical trials have shown that fourth-generation fluoroquinolones are better than the older generation fluoroquinolones and are as potent as combined fortified antibiotics against common pathogens that cause bacterial keratitis. Collagen cross-linking was shown to improve healing of infectious corneal ulcer in treatment-resistant cases or as an adjunct to antibiotics treatment. Conclusion. Fourth-generation fluoroquinolones are good alternatives to standard treatment of bacterial keratitis using combined fortified topical antibiotics. Collagen cross-linking may be considered in treatment-resistant infectious keratitis or as an adjunct to antibiotics therapy.

  3. A Preferred Home for Disrupted Stars

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    Observed burps from the shredding of stars by supermassive black holes suggest that this behavior is more common in an unusual type of galaxy. A new study has examined NGC 3156, an example from this galaxy type, to better understand what causes this preference.Stellar BetrayalAn artists illustration of a tidal disruption event, in which a star is sent on a plunging orbit near a supermassive black hole and is subsequently torn apart by the black holes tidal forces. [NASA/CXC/M.Weiss]Tidal disruption events (TDEs) are events where a star plunges too close to a supermassive black hole and is torn apart by the black holes tidal forces. Weve observed roughly a dozen of these violent events in the last five years, and we expect to finds hundreds to thousands more with future surveys.TDEs are triggered when a star is sent on a plunging orbit close to a supermassive black hole. But what sends the star into harms way? One possible culprit is a dynamical mechanism known as two-body relaxation. In this process, stars orbiting a black hole undergo individual starstar interactions that, with a close enough encounter, can send them on plunging orbits.Choosing an Unusual HostOne puzzle with TDEs is that they tend to be preferentially found in rather unusual galaxies: galaxies that recently exhibited a lot of star formation but are now quiescent. In particular, several of the TDEs have been discovered in what are known as E+A galaxies, a rare subtype of elliptical galaxy that has recently undergone a major starburst.Since this subtype makes up only ~0.1% of all galaxies, its surprising that weve found so many TDEs in E+A galaxies so far. So why the preference?In an effort to answer this question, two scientists, Nicholas Stone (Einstein Fellow at Columbia University) and Sjoert van Velzen (Hubble Fellow at Johns Hopkins University), have teamed up to examine a nearby E+A galaxy, NGC 3156.Tidal disruption rates as a function of central supermassive-black-hole mass. The blue curve

  4. Plasma-material interaction under simulated disruption conditions

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)

    1995-12-31

    Sudden evaporation of divertor plate surface under high heat load during tokamak plasma disruption instantaneously produces a vapor shield. The cloud of vaporized material prevents the divertor plates from the bulk of incoming energy flux and thus reduces the further material erosion. Dynamics and effectiveness of the vapor shield are studied experimentally at the 2MK-200 facility under simulated disruption conditions. (orig.).

  5. Prenatal Smoking Exposure, Low Birth Weight, and Disruptive Behavior Disorders

    Science.gov (United States)

    Nigg, Joel T.; Breslau, Naomi

    2007-01-01

    Background: Prenatal problems are among theorized etiologies for child disruptive behavior problems. A key question concerns whether etiological contributors are shared across the broad range of disruptive psychopathology or are partially or largely distinct. Method: We examined prenatal smoking exposure and low birth weight as risk factors for…

  6. ENDOCRINE-DISRUPTING CONTAMINANTS AND REPRODUCTION IN VERTEBRATE WILDLIFE.

    Science.gov (United States)

    The fields of toxicology, endocrinology, and reproductive physiology recently have combined resources to study the effects of endocrine-disrupting contaminants (EDCs) in wildlife populations. EDCs include a wide variety of chemicals that are only related by the ability to disrupt...

  7. Teachers' Perceptions of Disruptive Behaviour in Schools: A Psychological Perspective

    Science.gov (United States)

    Nash, Poppy; Schlösser, Annette; Scarr, Tanya

    2016-01-01

    This article reports on an investigation into school teachers' perceptions of disruptive behaviour from a psychological perspective. The inter-disciplinary nature of this research bridges the understanding between educational and psychological perspectives on disruptive behaviour. This article discusses evidence that for the most troubled pupils,…

  8. Noncontingent peer attention as treatment for disruptive classroom behavior.

    OpenAIRE

    Jones, K. M.; Drew, H A; Weber, N L

    2000-01-01

    A functional analysis isolated peer attention as the primary maintaining variable for disruptive behavior displayed by a student with attention deficit hyperactivity disorder. Using a brief reversal design, noncontingent reinforcement was then shown to reduce disruptive behavior relative to the peer attention condition. Implications for assessing behavior disorders in mainstream school settings are discussed.

  9. Testicular dysgenesis syndrome: possible role of endocrine disrupters

    DEFF Research Database (Denmark)

    Bay, Katrine; Asklund, Camilla; Skakkebaek, Niels E;

    2006-01-01

    and molecular studies, all suggestive of an interrelation between the different symptoms. The aetiology of TDS is suspected to be related to genetic and/or environmental factors, including endocrine disrupters. Few human studies have found associations/correlations between endocrine disrupters, including...

  10. Disruption management of the vehicle routing problem with vehicle breakdown

    DEFF Research Database (Denmark)

    Mu, Q; Fu, Z; Lysgaard, Jens;

    2011-01-01

    This paper introduces a new class of problem, the disrupted vehicle routing problem (VRP), which deals with the disruptions that occur at the execution stage of a VRP plan. The paper then focuses on one type of such problem, in which a vehicle breaks down during the delivery and a new routing...

  11. ENDOCRINE DISRUPTING EFFECTS OF BUTYLPARABEN: A REVIEW

    Directory of Open Access Journals (Sweden)

    Pallabi Goswami

    2013-01-01

    Full Text Available In recent years, there has been an increasing concern in the field of endocrine disruption over the presence of various endocrine disrupting chemicals in Pharmaceuticals and Personal care products (PPCPs. This concern has also been as PPCPs are most widely used and had led to introduction of thousands of new and complex chemicals that enter the environment in large quantities. The effect of the chemicals has not only been restricted to human who are exposed directly to the chemicals or the animals which gets exposed to the chemicals through wide variety of veterinary drugs, but also the aquatic organisms and other form of Wildlife which are non target and indirectly gets exposed to the chemicals through individual human activity. Parabens includes a group of compound of which methylparaben, butylparaben, ethylparaben, propylparaben are most widely used as preservatives in various PPCPs. Recent concern over the use of parabens has been drawn by the scientific community as these chemicals are reported to exert a weak estrogenic activity, with butylparaben showing the most potent activity among methyl-, ethyl- and propyl esters in in vitro recombinant yeast assay and in in vivo uterotrophic assay. Human exposure to butylparaben which occur mainly through inhalation, ingestion, or eye or skin contact, from intake of foods or drugs or use of cosmetics and personal care products where butylparaben is mainly used as a preservative. Effects of butylparaben are studied in various animal model systems like rodents to determine the possible effects in human which showed various effects which include defects in male reproductive system like increase in weight of epididymis, also change in serum testosterone level and a significant increase in uterine weight in ovariectomized and immature rats. Other effects include irritation to the respiratory tract, allergic skin reactions, atrophy of lymphoid tissue in the spleen, thymus, and lymph nodes and multifocal

  12. Supply Chain Disruptions Theory and Practice of Managing Risk

    CERN Document Server

    Mehrotra, Anuj; Ray, Saibal

    2012-01-01

    One of the most critical issues facing supply chain managers in today’s globalized and highly uncertain business environments is how to deal proactively with disruptions that might affect the complicated supply networks characterizing modern enterprises. Supply Chain Disruptions: Theory and Practice of Managing Risk presents a state-of the-art perspective on this particular issue. Supply Chain Disruptions: Theory and Practice of Managing Risk demonstrates that effective management of supply disruptions necessitates both strategic and tactical measures – the former involving optimal design of supply networks; the latter involving inventory, finance and demand management. It shows that managers ought to use all available levers at their disposal throughout the supply network – like sourcing and pricing strategies, providing financial subsidies, encouraging information sharing and incentive alignment between supply chain partners – in order to tackle supply disruptions. The editors combine up-to-date aca...

  13. Simulations of Magnetic Fields in Tidally-Disrupted Stars

    CERN Document Server

    Guillochon, James

    2016-01-01

    We perform the first magnetohydrodynamical simulations of tidal disruptions of stars by supermassive black holes. We consider stars with both tangled and ordered magnetic fields, for both grazing and deeply disruptive encounters. When the star survives disruption, we find its magnetic field amplifies by a factor of up to twenty, but see no evidence for the a self-sustaining dynamo that would yield arbitrary field growth. For stars that do not survive, and within the tidal debris streams produced in partial disruptions, we find that the component of the magnetic field parallel to the direction of stretching along the debris stream only decreases slightly with time, eventually resulting in a stream where the magnetic pressure is in equipartition with the gas. Our results suggest that the returning gas in most (if not all) stellar tidal disruptions is already highly magnetized by the time it returns to the black hole.

  14. Prediction of disruptions on ASDEX Upgrade using discriminant analysis

    International Nuclear Information System (INIS)

    In this paper, a set of simple predictive criteria, each optimized for a given type of disruption, is explored. Disruptions that occurred in the years from 2005 to 2009 in the ASDEX Upgrade tokamak are classified into several types in a first step. Then, discriminant analysis is used as the main approach to the disruption prediction and a log-linear discriminant function, constructed with five global plasma parameters that have been selected from an initial group of ten variables, is derived for the edge cooling disruptions. The function is tested off-line over 308 discharges and is shown to work reliably. It describes a clear dependence of the disruption boundary on the plasma parameters.

  15. Characterization of plasma current quench during disruption in EAST tokamak

    Institute of Scientific and Technical Information of China (English)

    陈大龙; 沈飙; 杨飞; 钱金平; 肖炳甲

    2015-01-01

    Preliminary analysis of plasma current quench is presented in this paper based on the disruption database. It demon-strates that 26.8%discharges have disrupted in the last 2012 campaign, in addition, plasma disruptive rate grows with the increase of plasma current. Best-fit linear and instantaneous plasma current quench rate is extracted from the recent EAST disruptions, showing that 80%–30%interval of the maximum plasma current is well fit for EAST device. The lowest area-normalized current quench time is 3.33 ms/m2 with the estimated plasma electron temperature being 7.3 eV∼9.5 eV. In the disruption case the maximum eddy current goes up to 400 kA, and a fraction of currents are respectively driven on upper and lower outer plate with nearly 100 MPa–200 MPa stress in the leg.

  16. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.;

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  17. Phylogenetic organization of bacterial activity.

    Science.gov (United States)

    Morrissey, Ember M; Mau, Rebecca L; Schwartz, Egbert; Caporaso, J Gregory; Dijkstra, Paul; van Gestel, Natasja; Koch, Benjamin J; Liu, Cindy M; Hayer, Michaela; McHugh, Theresa A; Marks, Jane C; Price, Lance B; Hungate, Bruce A

    2016-09-01

    Phylogeny is an ecologically meaningful way to classify plants and animals, as closely related taxa frequently have similar ecological characteristics, functional traits and effects on ecosystem processes. For bacteria, however, phylogeny has been argued to be an unreliable indicator of an organism's ecology owing to evolutionary processes more common to microbes such as gene loss and lateral gene transfer, as well as convergent evolution. Here we use advanced stable isotope probing with (13)C and (18)O to show that evolutionary history has ecological significance for in situ bacterial activity. Phylogenetic organization in the activity of bacteria sets the stage for characterizing the functional attributes of bacterial taxonomic groups. Connecting identity with function in this way will allow scientists to begin building a mechanistic understanding of how bacterial community composition regulates critical ecosystem functions. PMID:26943624

  18. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  19. Clinical applications of bacterial glycoproteins.

    Science.gov (United States)

    Fulton, Kelly M; Smith, Jeffrey C; Twine, Susan M

    2016-01-01

    There is an ongoing race between bacterial evolution and medical advances. Pathogens have the advantages of short generation times and horizontal gene transfer that enable rapid adaptation to new host environments and therapeutics that currently outpaces clinical research. Antibiotic resistance, the growing impact of nosocomial infections, cancer-causing bacteria, the risk of zoonosis, and the possibility of biowarfare all emphasize the increasingly urgent need for medical research focussed on bacterial pathogens. Bacterial glycoproteins are promising targets for alternative therapeutic intervention since they are often surface exposed, involved in host-pathogen interactions, required for virulence, and contain distinctive glycan structures. The potential exists to exploit these unique structures to improve clinical prevention, diagnosis, and treatment strategies. Translation of the potential in this field to actual clinical impact is an exciting prospect for fighting infectious diseases. PMID:26971465

  20. Shedding light on biology of bacterial cells.

    Science.gov (United States)

    Schneider, Johannes P; Basler, Marek

    2016-11-01

    To understand basic principles of living organisms one has to know many different properties of all cellular components, their mutual interactions but also their amounts and spatial organization. Live-cell imaging is one possible approach to obtain such data. To get multiple snapshots of a cellular process, the imaging approach has to be gentle enough to not disrupt basic functions of the cell but also have high temporal and spatial resolution to detect and describe the changes. Light microscopy has become a method of choice and since its early development over 300 years ago revolutionized our understanding of living organisms. As most cellular components are indistinguishable from the rest of the cellular contents, the second revolution came from a discovery of specific labelling techniques, such as fusions to fluorescent proteins that allowed specific tracking of a component of interest. Currently, several different tags can be tracked independently and this allows us to simultaneously monitor the dynamics of several cellular components and from the correlation of their dynamics to infer their respective functions. It is, therefore, not surprising that live-cell fluorescence microscopy significantly advanced our understanding of basic cellular processes. Current cameras are fast enough to detect changes with millisecond time resolution and are sensitive enough to detect even a few photons per pixel. Together with constant improvement of properties of fluorescent tags, it is now possible to track single molecules in living cells over an extended period of time with a great temporal resolution. The parallel development of new illumination and detection techniques allowed breaking the diffraction barrier and thus further pushed the resolution limit of light microscopy. In this review, we would like to cover recent advances in live-cell imaging technology relevant to bacterial cells and provide a few examples of research that has been possible due to imaging

  1. Fold modulating function: Bacterial toxins to functional amyloids

    Directory of Open Access Journals (Sweden)

    Adnan Khawaja Syed

    2014-08-01

    Full Text Available Many bacteria produce cytolytic toxins that target host cells or other competing microbes. It is well known that environmental factors control toxin expression, however recent work suggests that some bacteria manipulate the fold of these protein toxins to control their function. The β-sheet rich amyloid fold is a highly stable ordered aggregate that many toxins form in response to specific environmental conditions. When in the amyloid state, toxins become inert, losing the cytolytic activity they display in the soluble form. Emerging evidence suggest that some amyloids function as toxin storage systems until they are again needed, while other bacteria utilize amyloids as a structural matrix component of biofilms. This amyloid matrix component facilitates resistance to biofilm disruptive challenges. The bacterial amyloids discussed in this review reveal an elegant system where changes in protein fold and solubility dictate the function of proteins in response to the environment.

  2. Plasma temperature measurements in disruption simulated experiment

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)

    1995-12-31

    Results are reported of experiments to measure the temporal and spatial distributions of a temperature and radiation of a near surface plasma cloud appearing in the disruption simulated experiments. These measurements are needed to verificate the different numerical models of vapor shielding layer which appears to arise near the divertor plates surface and prevents them from the bulk of the incoming energy. Experiments with graphite and tungsten samples were carried out at the 2MK-200 plasma facility. Long CUSP trap was used as a source of high temperature deuterium plasma with a power density W = 10 MW/cm{sup 2} and time duration t = 20 mcs. Laser scattering, space and time resolved soft x-ray spectroscopy was employed to measure the plasma cloud temperature and radiation. The different behaviour of shielding layer parameters was shown for a graphite and tungsten samples. For a tungsten the sharp boundary existed between the incoming deuterium plasma and the thin layer of ablated material plasma and the strong gradient of electron temperature took place in this zone. For a graphite this boundary was broadened at the distance and the main part of the screening layer consisted of the mixture of the incoming deuterium and ablated carbon plasma. (orig.).

  3. Fungal Laccases Degradation of Endocrine Disrupting Compounds

    Directory of Open Access Journals (Sweden)

    Gemma Macellaro

    2014-01-01

    Full Text Available Over the past decades, water pollution by trace organic compounds (ng/L has become one of the key environmental issues in developed countries. This is the case of the emerging contaminants called endocrine disrupting compounds (EDCs. EDCs are a new class of environmental pollutants able to mimic or antagonize the effects of endogenous hormones, and are recently drawing scientific and public attention. Their widespread presence in the environment solicits the need of their removal from the contaminated sites. One promising approach to face this challenge consists in the use of enzymatic systems able to react with these molecules. Among the possible enzymes, oxidative enzymes are attracting increasing attention because of their versatility, the possibility to produce them on large scale, and to modify their properties. In this study five different EDCs were treated with four different fungal laccases, also in the presence of both synthetic and natural mediators. Mediators significantly increased the efficiency of the enzymatic treatment, promoting the degradation of substrates recalcitrant to laccase oxidation. The laccase showing the best performances was chosen to further investigate its oxidative capabilities against micropollutant mixtures. Improvement of enzyme performances in nonylphenol degradation rate was achieved through immobilization on glass beads.

  4. Pulvinar inactivation disrupts selection of movement plans.

    Science.gov (United States)

    Wilke, Melanie; Turchi, Janita; Smith, Katy; Mishkin, Mortimer; Leopold, David A

    2010-06-23

    The coordinated movement of the eyes and hands under visual guidance is an essential part of goal-directed behavior. Several cortical areas known to be involved in this process exchange projections with the dorsal aspect of the thalamic pulvinar nucleus, suggesting that this structure may play a central role in visuomotor behavior. Here, we used reversible inactivation to investigate the role of the dorsal pulvinar in the selection and execution of visually guided manual and saccadic eye movements in macaque monkeys. We found that unilateral pulvinar inactivation resulted in a spatial neglect syndrome accompanied by visuomotor deficits including optic ataxia during visually guided limb movements. Monkeys were severely disrupted in their visually guided behavior regarding space contralateral to the side of the injection in several domains, including the following: (1) target selection in both manual and oculomotor tasks, (2) limb usage in a manual retrieval task, and (3) spontaneous visual exploration. In addition, saccades into the ipsilesional field had abnormally short latencies and tended to overshoot their mark. None of the deficits could be explained by a visual field defect or primary motor deficit. These findings highlight the importance of the dorsal aspect of the pulvinar nucleus as a critical hub for spatial attention and selection of visually guided actions. PMID:20573910

  5. Primary realignment of the disrupted prostatomembranous urethra.

    Science.gov (United States)

    Devine, C J; Jordan, G H; Devine, P C

    1989-05-01

    Urethral scarring resulting in stricture formation can be avoided or minimized by proper treatment after injury. On presentation of the trauma patient, the possibility of such injury must be suspected and the urethra evaluated prior to any attempts at catheter placement. Diversion in all cases of posterior urethral injury should be by a suprapubic tube, with any urinary extravasation drained at the site of the injury. If the patient's general condition allows it, the disrupted urethra should be realigned by a catheter after the puboprostatic ligaments have been divided. These measures allow the prostate to return to the urogenital diaphragm without tension and in line with the distal urethra. Until the prostate is released, no amount of traction will reapproximate the urethra, and after it is released, traction is not necessary. The suprapubic catheter provides diversion, preventing further complications caused by urinary extravasation; urethral alignment minimizes subsequent stricture formation. When the stricture develops, if it is urodynamically significant, it can be repaired in 4 to 6 months. If one is fortunate, the stricture will be short and amenable to internal urethrotomy. If not, open reconstruction will be greatly facilitated by the attempts to guide the distracted ends of the urethra together. PMID:2711547

  6. Neuromuscular disruption with ultrashort electrical pulses

    Science.gov (United States)

    Pakhomov, Andrei; Kolb, Juergen F.; Joshi, Ravindra P.; Schoenbach, Karl H.; Dayton, Thomas; Comeaux, James; Ashmore, John; Beason, Charles

    2006-05-01

    Experimental studies on single cells have shown that application of pulsed voltages, with submicrosecond pulse duration and an electric field on the order of 10 kV/cm, causes sudden alterations in the intracellular free calcium concentration, followed by immobilization of the cell. In order to examine electrical stimulation and incapacitation with such ultrashort pulses, experiments on anesthetized rats have been performed. The effect of single, 450 nanosecond monopolar pulses have been compared with that of single pulses with multi-microsecond duration (TASER pulses). Two conditions were explored: 1. the ability to elicit a muscle twitch, and, 2. the ability to suppress voluntary movement by using nanosecond pulses. The second condition is relevant for neuromuscular incapacitation. The preliminary results indicate that for stimulation microsecond pulses are advantageous over nanosecond pulses, whereas for incapacitation, the opposite seems to apply. The stimulation effects seem to scale with electrical charge, whereas the disruption effects don't follow a simple scaling law. The increase in intensity (time of incapacitation) for a given pulse duration, is increasing with electrical energy, but is more efficient for nanosecond than for microsecond pulses. This indicates different cellular mechanisms for incapacitation, most likely subcellular processes, which have been shown to become increasingly important when the pulse duration is shortened into the nanosecond range. If further studies can confirm these initial results, consequences of reduced pulse duration are a reduction in weight and volume of the pulse delivery system, and likely, because of the lower required energy for neuromuscular incapacitation, reduced safety risks.

  7. Real Time Simulation of Power Grid Disruptions

    Energy Technology Data Exchange (ETDEWEB)

    Chinthavali, Supriya [ORNL; Dimitrovski, Aleksandar D [ORNL; Fernandez, Steven J [ORNL; Groer, Christopher S [ORNL; Nutaro, James J [ORNL; Olama, Mohammed M [ORNL; Omitaomu, Olufemi A [ORNL; Shankar, Mallikarjun [ORNL; Spafford, Kyle L [ORNL; Vacaliuc, Bogdan [ORNL

    2012-11-01

    DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

  8. Reward disrupts reactivated human skill memory.

    Science.gov (United States)

    Dayan, Eran; Laor-Maayany, Rony; Censor, Nitzan

    2016-01-01

    Accumulating evidence across species and memory domains shows that when an existing memory is reactivated, it becomes susceptible to modifications. However, the potential role of reward signals in these mechanisms underlying human memory dynamics is unknown. Leaning on a wealth of findings on the role of reward in reinforcing memory, we tested the impact of reinforcing a skill memory trace with monetary reward following memory reactivation, on strengthening of the memory trace. Reinforcing reactivated memories did not strengthen the memory, but rather led to disruption of the memory trace, breaking down the link between memory reactivation and subsequent memory strength. Statistical modeling further revealed a strong mediating role for memory reactivation in linking between memory encoding and subsequent memory strength only when the memory was replayed without reinforcement. We suggest that, rather than reinforcing the existing memory trace, reward creates a competing memory trace, impairing expression of the original reward-free memory. This mechanism sheds light on the processes underlying skill acquisition, having wide translational implications. PMID:27306380

  9. Disruption in a Neurodevelopmental Model of Schizophrenia

    Directory of Open Access Journals (Sweden)

    Benjamin Rolland

    2012-01-01

    Full Text Available Oxidative stress has been implicated in neurodevelopmental theories of schizophrenia. Antioxidant Peroxysome Proliferator-Activated Receptors α (PPARα agonist fenofibrate has neuroprotective properties and could reverse early preclinical infringements that could trigger the illness. We have evaluated the neuroprotective interest of fenofibrate in a neurodevelopmental rat model of schizophrenia. The oxidative lesion induced by Kainic Acid (KA injection at postnatal day (PND 7 has previously been reported to disrupt Prepulse Inhibition (PPI at PND56 but not at PND35. In 4 groups of 15 male rats each, KN (KA-PND7 + normal postweaning food, KF (KA-PND7 + fenofibrate 0.2% food, ON (saline-PND7 + normal food, and OF (saline + fenofibrate food, PPI was recorded at PND35 and PND56. Three levels of prepulse were used: 73 dB, 76 dB, and 82 dB for a pulse at 120 dB. Four PPI scores were analyzed: PPI73, PPI76, PPI82, and mean PPI (PPIm. Two-way ANOVAs were used to evaluate the effects of both factors (KA + fenofibrate, and, in case of significant results, intergroup Student’s t-tests were performed. We notably found a significant difference (P<0.05 in PPIm between groups KN and KF at PND56, which supposes that fenofibrate could be worthy of interest for early neuroprotection in schizophrenia.

  10. Disruption of Mitotic Progression by Arsenic.

    Science.gov (United States)

    States, J Christopher

    2015-07-01

    Arsenic is an enigmatic xenobiotic that causes a multitude of chronic diseases including cancer and also is a therapeutic with promise in cancer treatment. Arsenic causes mitotic delay and induces aneuploidy in diploid human cells. In contrast, arsenic causes mitotic arrest followed by an apoptotic death in a multitude of virally transformed cells and cancer cells. We have explored the hypothesis that these differential effects of arsenic exposure are related by arsenic disruption of mitosis and are differentiated by the target cell's ability to regulate or modify cell cycle checkpoints. Functional p53/CDKN1A axis has been shown to mitigate the mitotic block and to be essential to induction of aneuploidy. More recent preliminary data suggest that microRNA modulation of chromatid cohesion also may play a role in escape from mitotic block and in generation of chromosomal instability. Other recent studies suggest that arsenic may be useful in treatment of solid tumors when used in combination with other cytotoxic agents such as cisplatin.

  11. Tidal Disruption Events Prefer Unusual Host Galaxies

    CERN Document Server

    French, K Decker; Zabludoff, Ann

    2016-01-01

    Tidal Disruption Events (TDEs) are transient events observed when a star passes close enough to a supermassive black hole to be tidally destroyed. Many TDE candidates have been discovered in host galaxies whose spectra have weak or no line emission yet strong Balmer line absorption, indicating a period of intense star formation that has recently ended. As such, TDE host galaxies fall into the rare class of quiescent Balmer-strong galaxies. Here, we quantify the fraction of galaxies in the Sloan Digital Sky Survey (SDSS) with spectral properties like those of TDE hosts, determining the extent to which TDEs are over-represented in such galaxies. Galaxies whose spectra have Balmer absorption H$\\delta_{\\rm A}$ $-$ $\\sigma$(H$\\delta_{\\rm A}$) $>$ 4 \\AA\\ (where $\\sigma$(H$\\delta_{\\rm A}$) is the error in the Lick H$\\delta_{\\rm A}$ index) and H$\\alpha$ emission EW $$ 1.31 \\AA\\ and H$\\alpha$ EW $80\\times$ enhancement in such hosts and providing an observational link between the $\\gamma$/X-ray-bright and optical/UV-br...

  12. Ingestion of metal-nanoparticle contaminated food disrupts endogenous microbiota in zebrafish (Danio rerio)

    International Nuclear Information System (INIS)

    Nanoparticles (NPs) can be ingested by organisms, and NPs with antimicrobial properties may disrupt beneficial endogenous microbial communities and affect organism health. Zebrafish were fed diets containing Cu-NPs or Ag-NPs (500 mg kg−1 food), or an appropriate control for 14 d. Intestinal epithelium integrity was examined by transmission electron microscopy, and microbial community structure within the intestine was assessed by denaturing gradient gel electrophoresis (DGGE) of partial 16S rRNA. No lesions were observed in intestinal epithelia; however, presence of NPs in diets changed intestinal microbial community structure. In particular, some beneficial bacterial strains (e.g., Cetobacterium somerae) were suppressed to non-detectable levels by Cu-NP exposure, and two unidentified bacterial clones from the Firmicutes phylum were sensitive (not detected) to Cu, but were present in Ag and control fish. Unique changes in zebrafish microbiome caused by exposure to Ag-NP and Cu-NP indicate that NP ingestion could affect digestive system function and organism health. -- Highlights: ► Zebrafish ingest Cu- and Ag-nanoparticles (NPs) in diet. ► No effect of Cu-NPs or Ag-NPs on intestinal epithelial integrity. ► Cu-NPs and Ag-NPs alter endogenous microbiota of zebrafish. -- Dietary exposure to manufactured Cu- and Ag-nanoparticles caused unique changes in endogenous gut microbiota in zebrafish Danio rerio

  13. Circadian Disruption Alters the Effects of Lipopolysaccharide Treatment on Circadian and Ultradian Locomotor Activity and Body Temperature Rhythms of Female Siberian Hamsters.

    Science.gov (United States)

    Prendergast, Brian J; Cable, Erin J; Stevenson, Tyler J; Onishi, Kenneth G; Zucker, Irving; Kay, Leslie M

    2015-12-01

    The effect of circadian rhythm (CR) disruption on immune function depends on the method by which CRs are disrupted. Behavioral and thermoregulatory responses induced by lipopolysaccharide (LPS) treatment were assessed in female Siberian hamsters in which circadian locomotor activity (LMA) rhythms were eliminated by exposure to a disruptive phase-shifting protocol (DPS) that sustains arrhythmicity even when hamsters are housed in a light-dark cycle. This noninvasive treatment avoids genome manipulations and neurological damage associated with other models of CR disruption. Circadian rhythmic (RHYTH) and arrhythmic (ARR) hamsters housed in a 16L:8D photocycle were injected with bacterial LPS near the onset of the light (zeitgeber time 1; ZT1) or dark (ZT16) phase. LPS injections at ZT16 and ZT1 elicited febrile responses in both RHYTH and ARR hamsters, but the effect was attenuated in the arrhythmic females. In ZT16, LPS inhibited LMA in the dark phase immediately after injection but not on subsequent nights in both chronotypes; in contrast, LPS at ZT1 elicited more enduring (~4 day) locomotor hypoactivity in ARR than in RHYTH hamsters. Power and period of dark-phase ultradian rhythms (URs) in LMA and Tb were markedly altered by LPS treatment, as was the power in the circadian waveform. Disrupted circadian rhythms in this model system attenuated responses to LPS in a trait- and ZT-specific manner; changes in UR period and power are novel components of the acute-phase response to infection that may affect energy conservation.

  14. Disease notes - Bacterial root rot

    Science.gov (United States)

    Bacterial root rot initiated by lactic acid bacteria, particularly Leuconostoc, occurs every year in Idaho sugarbeet fields. Hot fall weather seems to make the problem worse. Although Leuconostoc initiates the rot, other bacteria and yeast frequently invade the tissue as well. The acetic acid bac...

  15. Biotechnological applications of bacterial cellulases

    Directory of Open Access Journals (Sweden)

    Esther Menendez

    2015-08-01

    Full Text Available Cellulases have numerous applications in several industries, including biofuel production, food and feed industry, brewing, pulp and paper, textile, laundry, and agriculture.Cellulose-degrading bacteria are widely spread in nature, being isolated from quite different environments. Cellulose degradation is the result of a synergic process between an endoglucanase, an exoglucanase and a,β-glucosidase. Bacterial endoglucanases degrade ß-1,4-glucan linkages of cellulose amorphous zones, meanwhile exoglucanases cleave the remaining oligosaccharide chains, originating cellobiose, which is hydrolyzed by ß-glucanases. Bacterial cellulases (EC 3.2.1.4 are comprised in fourteen Glycosil Hydrolase families. Several advantages, such as higher growth rates and genetic versatility, emphasize the suitability and advantages of bacterial cellulases over other sources for this group of enzymes. This review summarizes the main known cellulolytic bacteria and the best strategies to optimize their cellulase production, focusing on endoglucanases, as well as it reviews the main biotechnological applications of bacterial cellulases in several industries, medicine and agriculture.

  16. A Program Against Bacterial Bioterrorism

    DEFF Research Database (Denmark)

    Kemp, Michael; Dargis, Rimtas; Andresen, Keld;

    2012-01-01

    In 2002 it was decided to establish laboratory facilities in Denmark for diagnosing agents associated with bioterrorism in order to make an immediate appropriate response to the release of such agents possible. Molecular assays for detection of specific agents and molecular and proteomic techniques...... for bacterial infections not associated with bioterrorism that are difficult to culture or identify....

  17. Molecular Mechanisms Underlying Bacterial Persisters

    DEFF Research Database (Denmark)

    Maisonneuve, Etienne; Gerdes, Kenn

    2014-01-01

    technological advances in microfluidics and reporter genes have improved this scenario. Here, we summarize recent progress in the field, revealing the ubiquitous bacterial stress alarmone ppGpp as an emerging central regulator of multidrug tolerance and persistence, both in stochastically and environmentally...

  18. Environmental endocrine disruption: an effects assessment and analysis.

    Science.gov (United States)

    Crisp, T M; Clegg, E D; Cooper, R L; Wood, W P; Anderson, D G; Baetcke, K P; Hoffmann, J L; Morrow, M S; Rodier, D J; Schaeffer, J E; Touart, L W; Zeeman, M G; Patel, Y M

    1998-02-01

    This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analyze the available information, and provide a reasonable assessment of the problem. Emphasis is placed on disruption of central nervous system--pituitary integration of hormonal and sexual behavioral activity, female and male reproductive system development and function, and thyroid function. In addition, the potential role of environmental endocrine disruption in the induction of breast, testicular, and prostate cancers, as well as endometriosis, is evaluated. The interrelationship of the endocrine and immune system is documented. With respect to endocrine-related ecological effects, specific case examples from the peer-reviewed literature of marine invertebrates and representatives of the five classes of vertebrates are presented and discussed. The report identifies some data gaps in our understanding of the environmental endocrine disruption issue and recommends a few research needs. Finally, the report states the U.S. Environmental Protection Agency Science Policy Council's interim position on endocrine disruption and lists some of the ongoing activities to deal with this matter. PMID:9539004

  19. Designing reliable supply chain network with disruption risk

    Directory of Open Access Journals (Sweden)

    Ali Bozorgi Amiri

    2013-01-01

    Full Text Available Although supply chains disruptions rarely occur, their negative effects are prolonged and severe. In this paper, we propose a reliable capacitated supply chain network design (RSCND model by considering random disruptions in both distribution centers and suppliers. The proposed model determines the optimal location of distribution centers (DC with the highest reliability, the best plan to assign customers to opened DCs and assigns opened DCs to suitable suppliers with lowest transportation cost. In this study, random disruption occurs at the location, capacity of the distribution centers (DCs and suppliers. It is assumed that a disrupted DC and a disrupted supplier may lose a portion of their capacities, and the rest of the disrupted DC's demand can be supplied by other DCs. In addition, we consider shortage in DCs, which can occur in either normal or disruption conditions and DCs, can support each other in such circumstances. Unlike other studies in the extent of literature, we use new approach to model the reliability of DCs; we consider a range of reliability instead of using binary variables. In order to solve the proposed model for real-world instances, a Non-dominated Sorting Genetic Algorithm-II (NSGA-II is applied. Preliminary results of testing the proposed model of this paper on several problems with different sizes provide seem to be promising.

  20. Disruptive Event Biosphere Doser Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M. Wasiolek

    2000-12-28

    The purpose of this report was to document the process leading to, and the results of, development of radionuclide-, exposure scenario-, and ash thickness-specific Biosphere Dose Conversion Factors (BDCFs) for the postulated postclosure extrusive igneous event (volcanic eruption) at Yucca Mountain. BDCF calculations were done for seventeen radionuclides. The selection of radionuclides included those that may be significant dose contributors during the compliance period of up to 10,000 years, as well as radionuclides of importance for up to 1 million years postclosure. The approach documented in this report takes into account human exposure during three different phases at the time of, and after, volcanic eruption. Calculations of disruptive event BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. The pathway analysis included consideration of different exposure pathway's contribution to the BDCFs. BDCFs for volcanic eruption, when combined with the concentration of radioactivity deposited by eruption on the soil surface, allow calculation of potential radiation doses to the receptor of interest. Calculation of radioactivity deposition is outside the scope of this report and so is the transport of contaminated ash from the volcano to the location of the receptor. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA), in which doses are calculated to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain.

  1. Disruptive Event Biosphere Doser Conversion Factor Analysis

    International Nuclear Information System (INIS)

    The purpose of this report was to document the process leading to, and the results of, development of radionuclide-, exposure scenario-, and ash thickness-specific Biosphere Dose Conversion Factors (BDCFs) for the postulated postclosure extrusive igneous event (volcanic eruption) at Yucca Mountain. BDCF calculations were done for seventeen radionuclides. The selection of radionuclides included those that may be significant dose contributors during the compliance period of up to 10,000 years, as well as radionuclides of importance for up to 1 million years postclosure. The approach documented in this report takes into account human exposure during three different phases at the time of, and after, volcanic eruption. Calculations of disruptive event BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. The pathway analysis included consideration of different exposure pathway's contribution to the BDCFs. BDCFs for volcanic eruption, when combined with the concentration of radioactivity deposited by eruption on the soil surface, allow calculation of potential radiation doses to the receptor of interest. Calculation of radioactivity deposition is outside the scope of this report and so is the transport of contaminated ash from the volcano to the location of the receptor. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA), in which doses are calculated to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain

  2. Major disruption of D″ beneath Alaska

    Science.gov (United States)

    Sun, Daoyuan; Helmberger, Don; Miller, Meghan S.; Jackson, Jennifer M.

    2016-05-01

    D″ represents one of the most dramatic thermal and compositional layers within our planet. In particular, global tomographic models display relatively fast patches at the base of the mantle along the circum-Pacific which are generally attributed to slab debris. Such distinct patches interact with the bridgmanite (Br) to post-bridgmanite (PBr) phase boundary to generate particularly strong heterogeneity at their edges. Most seismic observations for the D″ come from the lower mantle S wave triplication (Scd). Here we exploit the USArray waveform data to examine one of these sharp transitions in structure beneath Alaska. From west to east beneath Alaska, we observed three different characteristics in D″: (1) the western region with a strong Scd, requiring a sharp δVs = 2.5% increase; (2) the middle region with no clear Scd phases, indicating a lack of D″ (or thin Br-PBr layer); and (3) the eastern region with strong Scd phase, requiring a gradient increase in δVs. To explain such strong lateral variation in the velocity structure, chemical variations must be involved. We suggest that the western region represents relatively normal mantle. In contrast, the eastern region is influenced by a relic slab that has subducted down to the lowermost mantle. In the middle region, we infer an upwelling structure that disrupts the Br-PBr phase boundary. Such an interpretation is based upon a distinct pattern of travel time delays, waveform distortions, and amplitude patterns that reveal a circular-shaped anomaly about 5° across which can be modeled synthetically as a plume-like structure rising about 400 km high with a shear velocity reduction of ~5%, similar to geodynamic modeling predictions of upwellings.

  3. VIEWING URBAN DISRUPTIONS FROM A DECISION INFORMATICS PERSPECTIVE

    Institute of Scientific and Technical Information of China (English)

    James M. TIEN

    2005-01-01

    Urban infrastructures are the focus of terrorist acts because, quite simply, they produce the most visible impact, if not casualties. While terrorist acts are the most insidious and onerous of all disruptions, it is obvious that there are many similarities to the way one should deal with these willful acts and those caused by natural and accidental incidents that have also resulted in adverse and severe consequences. However, there is one major and critical difference between terrorist acts and the other types of disruptions: the terrorist acts are willful - and therefore also adaptive, if not coordinated. One must counter these acts with the same, if not more sophisticated, willful, adaptive and informed approach. Real-time, information-based decision making - which Tien (2003) has called the decision informatics paradigm - is the approach advanced herein to help make the right decisions at the various stages of a disruption. It is focused on decisions and based on multiple data sources, data fusion and analysis methods, timely information, stochastic decision models and a systems engineering outlook; moreover, it is multidisciplinary, evolutionary and systemic in practice. The approach provides a consistent way to address real-time emergency issues, including those concerned with the preparation for a major disruption, the prediction of such a disruption, the prevention or mitigation of the disruption, the detection of the disruption, the response to the disruption, and the recovery steps that are necessary to adequately, ifnot fully, recuperate from the disruption. The efforts of the U. S. Department of Homeland Security and its academically-based Homeland Security Centers of Excellence are considered within the proposed types, stages and decisions framework.

  4. Sleep Deprivation and Circadian Disruption: Stress, Allostasis, and Allostatic Load.

    Science.gov (United States)

    McEwen, Bruce S; Karatsoreos, Ilia N

    2015-03-01

    Sleep has important homeostatic functions, and circadian rhythms organize physiology and behavior on a daily basis to insure optimal function. Sleep deprivation and circadian disruption can be stressors, enhancers of other stressors that have consequences for the brain and many body systems. Whether the origins of circadian disruption and sleep disruption and deprivation are from anxiety, depression, shift work, long-distance air travel, or a hectic lifestyle, there are consequences that impair brain functions and contribute to the cumulative wear and tear on body systems caused by too much stress and/or inefficient management of the systems that promote adaptation. PMID:26055668

  5. Identifying workflow disruptions in the cardiovascular operating room.

    Science.gov (United States)

    Cohen, T N; Cabrera, J S; Sisk, O D; Welsh, K L; Abernathy, J H; Reeves, S T; Wiegmann, D A; Shappell, S A; Boquet, A J

    2016-08-01

    The objectives of this study were to identify the frequency and nature of flow disruptions in the operating room with respect to three cardiac surgical team members: anaesthetists; circulating nurses; and perfusionists. Data collected from 15 cases and coded using a human factors taxonomy identified 878 disruptions. Significant differences were identified in frequency relative to discipline type. Circulating nurses experienced more coordination disruptions (χ(2) (2, N = 110) = 7.136, p role. PMID:27396248

  6. Science and policy on endocrine disrupters must not be mixed

    DEFF Research Database (Denmark)

    Bergman, Åke; Andersson, Anna-Maria; Becher, Georg;

    2013-01-01

    a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail. We call for a better founded scientific debate which may help to overcome a polarisation......The "common sense" intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about...... of views detrimental to reaching a consensus about scientific foundations for endocrine disrupter regulation in the EU....

  7. Human biological monitoring of suspected endocrine-disrupting compounds

    Directory of Open Access Journals (Sweden)

    Moosa Faniband

    2014-02-01

    Full Text Available Endocrine-disrupting compounds are exogenous agents that interfere with the natural hormones of the body. Human biological monitoring is a powerful method for monitoring exposure to endocrine disrupting compounds. In this review, we describe human biological monitoring systems for different groups of endocrine disrupting compounds, polychlorinated biphenyls, brominated flame retardants, phthalates, alkylphenols, pesticides, metals, perfluronated compounds, parabens, ultraviolet filters, and organic solvents. The aspects discussed are origin to exposure, metabolism, matrices to analyse, analytical determination methods, determinants, and time trends.

  8. Inadequate clearance of translocated bacterial products in HIV-infected humanized mice.

    Directory of Open Access Journals (Sweden)

    Ursula Hofer

    2010-04-01

    Full Text Available Bacterial translocation from the gut and subsequent immune activation are hallmarks of HIV infection and are thought to determine disease progression. Intestinal barrier integrity is impaired early in acute retroviral infection, but levels of plasma lipopolysaccharide (LPS, a marker of bacterial translocation, increase only later. We examined humanized mice infected with HIV to determine if disruption of the intestinal barrier alone is responsible for elevated levels of LPS and if bacterial translocation increases immune activation. Treating uninfected mice with dextran sodium sulfate (DSS induced bacterial translocation, but did not result in elevated plasma LPS levels. DSS-induced translocation provoked LPS elevation only when phagocytic cells were depleted with clodronate liposomes (clodrolip. Macrophages of DSS-treated, HIV-negative mice phagocytosed more LPS ex vivo than those of control mice. In HIV-infected mice, however, LPS phagocytosis was insufficient to clear the translocated LPS. These conditions allowed higher levels of plasma LPS and CD8+ cell activation, which were associated with lower CD4+/CD8+ cell ratios and higher viral loads. LPS levels reflect both intestinal barrier and LPS clearance. Macrophages are essential in controlling systemic bacterial translocation, and this function might be hindered in chronic HIV infection.

  9. Defensive remodeling: How bacterial surface properties and biofilm formation promote resistance to antimicrobial peptides.

    Science.gov (United States)

    Nuri, Reut; Shprung, Tal; Shai, Yechiel

    2015-11-01

    Multidrug resistance bacteria are a major concern worldwide. These pathogens cannot be treated with conventional antibiotics and thus alternative therapeutic agents are needed. Antimicrobial peptides (AMPs) are considered to be good candidates for this purpose. Most AMPs are short and positively charged amphipathic peptides, which are found in all known forms of life. AMPs are known to kill bacteria by binding to the negatively charged bacterial surface, and in most cases cause membrane disruption. Resistance toward AMPs can be developed, by modification of bacterial surface molecules, secretion of protective material and up-regulation or elimination of specific proteins. Because of the general mechanisms of attachment and action of AMPs, bacterial resistance to AMPs often involves biophysical and biochemical changes such as surface rigidity, cell wall thickness, surface charge, as well as membrane and cell wall modification. Here we focus on the biophysical, surface and surrounding changes that bacteria undergo in acquiring resistance to AMPs. In addition we discuss the question of whether bacterial resistance to administered AMPs might compromise our innate immunity to endogenous AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

  10. Effects of disruption of heat shock genes on susceptibility of Escherichia coli to fluoroquinolones

    Directory of Open Access Journals (Sweden)

    Morioka Mizue

    2003-08-01

    Full Text Available Abstract Background It is well known that expression of certain bacterial genes responds rapidly to such stimuli as exposure to toxic chemicals and physical agents. It is generally believed that the proteins encoded in these genes are important for successful survival of the organism under the hostile conditions. Analogously, the proteins induced in bacterial cells exposed to antibiotics are believed to affect the organisms' susceptibility to these agents. Results We demonstrated that Escherichia coli cells exposed to levofloxacin (LVFX, a fluoroquinolone (FQ, induce the syntheses of heat shock proteins and RecA. To examine whether the heat shock proteins affect the bactericidal action of FQs, we constructed E. coli strains with mutations in various heat shock genes and tested their susceptibility to FQs. Mutations in dnaK, groEL, and lon increased this susceptibility; the lon mutant exhibited the greatest effects. The increased susceptibility of the lon mutant was corroborated by experiments in which the gene encoding the cell division inhibitor, SulA, was subsequently disrupted. SulA is induced by the SOS response and degraded by the Lon protease. The findings suggest that the hypersusceptibility of the lon mutant to FQs could be due to abnormally high levels of SulA protein resulting from the depletion of Lon and the continuous induction of the SOS response in the presence of FQs. Conclusion The present results show that the bactericidal action of FQs is moderately affected by the DnaK and GroEL chaperones and strongly affected by the Lon protease. FQs have contributed successfully to the treatment of various bacterial infections, but their widespread use and often misuse, coupled with emerging resistance, have gradually compromised their utility. Our results suggest that agents capable of inhibiting the Lon protease have potential for combination therapy with FQs.

  11. A C-type lectin from Bothrops jararacussu venom disrupts Staphylococcal biofilms.

    Directory of Open Access Journals (Sweden)

    Raphael Contelli Klein

    Full Text Available Bovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S. aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S. aureus. Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16 showed the best activities and were also assayed against S. epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S. aureus and S. epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S. epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S. aureus, S. hyicus, S. chromogenes, Streptococcus agalactiae, and Escherichia coli. These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model.

  12. Cognitive outcome in adults after bacterial meningitis.

    NARCIS (Netherlands)

    Hoogman, M.; Beek, D. van de; Weisfelt, M.; Gans, J. de; Schmand, B.

    2007-01-01

    OBJECTIVE: To evaluate cognitive outcome in adult survivors of bacterial meningitis. METHODS: Data from three prospective multicentre studies were pooled and reanalysed, involving 155 adults surviving bacterial meningitis (79 after pneumococcal and 76 after meningococcal meningitis) and 72 healthy c

  13. Amyloid-linked cellular toxicity triggered by bacterial inclusion bodies

    International Nuclear Information System (INIS)

    The aggregation of proteins in the form of amyloid fibrils and plaques is the characteristic feature of some pathological conditions ranging from neurodegenerative disorders to systemic amyloidoses. The mechanisms by which the aggregation processes result in cell damage are under intense investigation but recent data indicate that prefibrillar aggregates are the most proximate mediators of toxicity rather than mature fibrils. Since it has been shown that prefibrillar forms of the nondisease-related misfolded proteins are highly toxic to cultured mammalian cells we have studied the cytoxicity associated to bacterial inclusion bodies that have been recently described as protein deposits presenting amyloid-like structures. We have proved that bacterial inclusion bodies composed by a misfolding-prone β-galactosidase fusion protein are clearly toxic for mammalian cells but the β-galactosidase wild type enzyme forming more structured thermal aggregates does not impair cell viability, despite it also binds and enter into the cells. These results are in the line that the most cytotoxic aggregates are early prefibrilar assemblies but discard the hypothesis that the membrane destabilization is Key event to subsequent disruption of cellular processes, such as ion balance, oxidative state and the eventually cell death

  14. Transcriptional response of Musca domestica larvae to bacterial infection.

    Directory of Open Access Journals (Sweden)

    Ting Tang

    Full Text Available The house fly Musca domestica, a cosmopolitan dipteran insect, is a significant vector for human and animal bacterial pathogens, but little is known about its immune response to these pathogens. To address this issue, we inoculated the larvae with a mixture of Escherichia coli and Staphylococcus aureus and profiled the transcriptome 6, 24, and 48 h thereafter. Many genes known to controlling innate immunity in insects were induced following infection, including genes encoding pattern recognition proteins (PGRPs, various components of the Toll and IMD signaling pathways and of the proPO-activating and redox systems, and multiple antimicrobial peptides. Interestingly, we also uncovered a large set of novel immune response genes including two broad-spectrum antimicrobial peptides (muscin and domesticin, which might have evolved to adapt to house-fly's unique ecological environments. Finally, genes mediating oxidative phosphorylation were repressed at 48 h post-infection, suggesting disruption of energy homeostasis and mitochondrial function at the late stages of infection. Collectively, our data reveal dynamic changes in gene expression following bacterial infection in the house fly, paving the way for future in-depth analysis of M. domestica's immune system.

  15. Complete Genome Sequence of Cell Culture-Attenuated Guinea Pig Cytomegalovirus Cloned as an Infectious Bacterial Artificial Chromosome

    OpenAIRE

    Yang, Dongmei; Alam, Zohaib; Cui, Xiaohong; Chen, Michael; Sherrod, Carly J.; McVoy, Michael A.; Schleiss, Mark R.; Dittmer, Dirk P

    2014-01-01

    The complete genome sequence of attenuated guinea pig cytomegalovirus cloned as bacterial artificial chromosome N13R10 was determined. Comparison to pathogenic salivary gland-derived virus revealed 13 differences, 1 of which disrupted overlapping open reading frames encoding GP129 and GP130. Attenuation of N13R10 may arise from an inability to express GP129 and/or GP130.

  16. Filtration properties of bacterial cellulose membranes

    OpenAIRE

    Lehtonen, Janika

    2015-01-01

    Bacterial cellulose has the same molecular formula as cellulose from plant origin, but it is characterized by several unique properties including high purity, crystallinity and mechanical strength. These properties are dependent on parameters such as the bacterial strain used, the cultivation conditions and post-growth processing. The possibility to achieve bacterial cellulose membranes with different properties by varying these parameters could make bacterial cellulose an interesting materi...

  17. Branched Peptide, B2088, Disrupts the Supramolecular Organization of Lipopolysaccharides and Sensitizes the Gram-negative Bacteria

    Science.gov (United States)

    Lakshminarayanan, Rajamani; Tan, Wei Xiang; Aung, Thet Tun; Goh, Eunice Tze Leng; Muruganantham, Nandhakumar; Li, Jianguo; Chang, Jamie Ya Ting; Dikshit, Neha; Saraswathi, Padmanabhan; Lim, Rayne Rui; Kang, Tse Siang; Balamuralidhar, Vanniarajan; Sukumaran, Bindu; Verma, Chandra S.; Sivaraman, Jayaraman; Chaurasia, Shyam Sunder; Liu, Shouping; Beuerman, Roger W.

    2016-05-01

    Dissecting the complexities of branched peptide-lipopolysaccharides (LPS) interactions provide rationale for the development of non-cytotoxic antibiotic adjuvants. Using various biophysical methods, we show that the branched peptide, B2088, binds to lipid A and disrupts the supramolecular organization of LPS. The disruption of outer membrane in an intact bacterium was demonstrated by fluorescence spectroscopy and checkerboard assays, the latter confirming strong to moderate synergism between B2088 and various classes of antibiotics. The potency of synergistic combinations of B2088 and antibiotics was further established by time-kill kinetics, mammalian cell culture infections model and in vivo model of bacterial keratitis. Importantly, B2088 did not show any cytotoxicity to corneal epithelial cells for at least 96 h continuous exposure or hemolytic activity even at 20 mg/ml. Peptide congeners containing norvaline, phenylalanine and tyrosine (instead of valine in B2088) displayed better synergism compared to other substitutions. We propose that high affinity and subsequent disruption of the supramolecular assembly of LPS by the branched peptides are vital for the development of non-cytotoxic antibiotic adjuvants that can enhance the accessibility of conventional antibiotics to the intracellular targets, decrease the antibiotic consumption and holds promise in averting antibiotic resistance.

  18. Disruption of root carbon transport into forest humus stimulates fungal opportunists at the expense of mycorrhizal fungi.

    Science.gov (United States)

    Lindahl, Björn D; de Boer, Wietse; Finlay, Roger D

    2010-07-01

    Ectomycorrhizal fungi dominate the humus layers of boreal forests. They depend on carbohydrates that are translocated through roots, via fungal mycelium to microsites in the soil, wherein they forage for nutrients. Mycorrhizal fungi are therefore sensitive to disruptive disturbances that may restrict their carbon supply. By disrupting root connections, we induced a sudden decline in mycorrhizal mycelial abundance and studied the consequent effects on growth and activity of free living, saprotrophic fungi and bacteria in pine forest humus, using molecular community analyses in combination with enzyme activity measurements. Ectomycorrhizal fungi had decreased in abundance 14 days after root severing, but the abundance of certain free-living ascomycetes was three times higher within 5 days of the disturbance compared with undisturbed controls. Root disruption also increased laccase production by an order of magnitude and cellulase production by a factor of 5. In contrast, bacterial populations seemed little affected. The results indicate that access to an external carbon source enables mycorrhizal fungi to monopolise the humus, but disturbances may induce rapid growth of opportunistic saprotrophic fungi that presumably use the dying mycorrhizal mycelium. Studies of such functional shifts in fungal communities, induced by disturbance, may shed light on mechanisms behind nutrient retention and release in boreal forests. The results also highlight the fundamental problems associated with methods that study microbial processes in soil samples that have been isolated from living roots.

  19. Functional comparison of the binding of factor H short consensus repeat 6 (SCR 6) to factor H binding protein from Neisseria meningitidis and the binding of factor H SCR 18 to 20 to Neisseria gonorrhoeae porin.

    Science.gov (United States)

    Shaughnessy, Jutamas; Lewis, Lisa A; Jarva, Hanna; Ram, Sanjay

    2009-05-01

    Both Neisseria meningitidis and Neisseria gonorrhoeae recruit the alternative pathway complement inhibitory protein factor H (fH) to their surfaces to evade complement-dependent killing. Meningococci bind fH via fH binding protein (fHbp), a surface-exposed lipoprotein that is subdivided into three variant families based on one classification scheme. Chimeric proteins that comprise contiguous domains of fH fused to murine Fc were used to localize the binding site for all three fHbp variants on fH to short consensus repeat 6 (SCR 6). As expected, fH-like protein 1 (FHL-1), which contains fH SCR 6, also bound to fHbp-expressing meningococci. Using site-directed mutagenesis, we identified histidine 337 and histidine 371 in SCR 6 as important for binding to fHbp. These findings may provide the molecular basis for recent observations that demonstrated human-specific fH binding to meningococci. Differences in the interactions of fHbp variants with SCR 6 were evident. Gonococci bind fH via their porin (Por) molecules (PorB.1A or PorB.1B); sialylation of lipooligosaccharide enhances fH binding. Both sialylated PorB.1B- and (unsialylated) PorB.1A-bearing gonococci bind fH through SCR 18 to 20; PorB.1A can also bind SCR 6, but only weakly, as evidenced by a low level of binding of FHL-1 relative to that of fH. Using isogenic strains expressing either meningococcal fHbp or gonococcal PorB.1B, we discovered that strains expressing gonococcal PorB.1B in the presence of sialylated lipooligosaccharide bound more fH, more effectively limited C3 deposition, and were more serum resistant than their isogenic counterparts expressing fHbp. Differences in fH binding to these two related pathogens may be important for modulating their individual responses to host immune attack.

  20. Distribution of Triplet Separators in Bacterial Genomes

    Institute of Scientific and Technical Information of China (English)

    HU Rui; ZHENG Wei-Mou

    2001-01-01

    Distributions of triplet separator lengths for two bacterial complete genomes are analyzed. The theoretical distributions for the independent random sequence and the first-order Markov chain are derived and compared with the distributions of the bacterial genomes. A prominent double band structure, which does not exist in the theoretical distributions, is observed in the bacterial distributions for most triplets.``

  1. Simulating Impacts of Disruptions to Liquid Fuels Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Resilience and Regulatory Effects; Corbet, Thomas F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Policy and Decision Analytics; Baker, Arnold B. [ABB Consulting, Albuquerque, NM (United States); O' Rourke, Julia M. [Univ. of Texas, Austin, TX (United States). Dept. of Mechanical Engineering

    2015-04-01

    This report presents a methodology for estimating the impacts of events that damage or disrupt liquid fuels infrastructure. The impact of a disruption depends on which components of the infrastructure are damaged, the time required for repairs, and the position of the disrupted components in the fuels supply network. Impacts are estimated for seven stressing events in regions of the United States, which were selected to represent a range of disruption types. For most of these events the analysis is carried out using the National Transportation Fuels Model (NTFM) to simulate the system-level liquid fuels sector response. Results are presented for each event, and a brief cross comparison of event simulation results is provided.

  2. Interpreting debris from satellite disruption in external galaxies

    NARCIS (Netherlands)

    Johnston, KV; Sackett, PD; Bullock, JS

    2001-01-01

    We examine the detectability and interpretation of debris trails caused by satellite disruption in external galaxies using semianalytic approximations for the dependence of streamer length, width, and surface brightness on satellite and primary galaxy characteristics. The semianalytic method is test

  3. Amyloid Aggregation and Membrane Disruption by Amyloid Proteins

    Science.gov (United States)

    Ramamoorthy, Ayyalusamy

    2013-03-01

    Amyloidogenesis has been the focus of intense basic and clinical research, as an increasing number of amyloidogenic proteins have been linked to common and incurable degenerative diseases including Alzheimer's, type II diabetes, and Parkinson's. Recent studies suggest that the cell toxicity is mainly due to intermediates generated during the assembly process of amyloid fibers, which have been proposed to attack cells in a variety of ways. Disruption of cell membranes is believed to be one of the key components of amyloid toxicity. However, the mechanism by which this occurs is not fully understood. Our research in this area is focused on the investigation of the early events in the aggregation and membrane disruption of amyloid proteins, Islet amyloid polypeptide protein (IAPP, also known as amylin) and amyloid-beta peptide, on the molecular level. Structural insights into the mechanisms of membrane disruption by these amyloid proteins and the role of membrane components on the membrane disruption will be presented.

  4. ENDOCRINE DISRUPTING CONTAMINANTS AND ALLIGATOR EMBRYOS: A LESSON FROM WILDLIFE?

    Science.gov (United States)

    Many xenobiotic compounds introduced into the environment by human activity adversely affect wildlife. A number of these contaminants have been hypothesized to induce non lethal, multigenerational effects by acting as endocrine disrupting agents. One case is that of the alligator...

  5. Massive Open Online Courses (MOOC) Disruptive Impact on Higher Education

    OpenAIRE

    Stepan, Anita

    2013-01-01

    This paper presents a strategic analysis of online education, in particular, massive open online courses (MOOCs), and the disruptive impact of MOOCs on traditional faceto-face higher educational instructional models.

  6. Total sleep deprivation, chronic sleep restriction and sleep disruption.

    Science.gov (United States)

    Reynolds, Amy C; Banks, Siobhan

    2010-01-01

    Sleep loss may result from total sleep deprivation (such as a shift worker might experience), chronic sleep restriction (due to work, medical conditions or lifestyle) or sleep disruption (which is common in sleep disorders such as sleep apnea or restless legs syndrome). Total sleep deprivation has been widely researched, and its effects have been well described. Chronic sleep restriction and sleep disruption (also known as sleep fragmentation) have received less experimental attention. Recently, there has been increasing interest in sleep restriction and disruption as it has been recognized that they have a similar impact on cognitive functioning as a period of total sleep deprivation. Sleep loss causes impairments in cognitive performance and simulated driving and induces sleepiness, fatigue and mood changes. This review examines recent research on the effects of sleep deprivation, restriction and disruption on cognition and neurophysiologic functioning in healthy adults, and contrasts the similarities and differences between these three modalities of sleep loss.

  7. Cost Consequences of a Port-Related Supply Chain Disruption

    Directory of Open Access Journals (Sweden)

    Hui Shan LOH

    2015-09-01

    Full Text Available Port functionality is a significant and important aspect of cargo transportation. Previous studies have identified a list of port-related supply chain disruption threats and developed a management model that seeks to address these threats. This paper adds value to these related studies by comparing four consequences of an example of these threats: (1 avoidance of disruption, (2 mitigation of disruption, (3 deviation of transportation plan and (4 delays and deviation of transportation plan. The impact of these consequences is simulated in a case study using data from a chemical manufacturer based in Singapore. This paper quantitatively measures the impact of a port-related threat on supply chains and thus highlights the importance of port-related supply chain disruption management.

  8. When a Few Disruptive Students Challenge an Instructor's Plan.

    Science.gov (United States)

    Kilmer, Paulette D.

    1998-01-01

    Discusses how one journalism instructor deals with disruptive students in her reporting, communication history, and ethics courses. Lists reasons for students' disenchantment. Notes that sometimes humor eases tensions. Addresses building respect in the college classroom. (RS)

  9. Genetic and computational identification of a conserved bacterial metabolic module.

    Directory of Open Access Journals (Sweden)

    Cara C Boutte

    2008-12-01

    Full Text Available We have experimentally and computationally defined a set of genes that form a conserved metabolic module in the alpha-proteobacterium Caulobacter crescentus and used this module to illustrate a schema for the propagation of pathway-level annotation across bacterial genera. Applying comprehensive forward and reverse genetic methods and genome-wide transcriptional analysis, we (1 confirmed the presence of genes involved in catabolism of the abundant environmental sugar myo-inositol, (2 defined an operon encoding an ABC-family myo-inositol transmembrane transporter, and (3 identified a novel myo-inositol regulator protein and cis-acting regulatory motif that control expression of genes in this metabolic module. Despite being encoded from non-contiguous loci on the C. crescentus chromosome, these myo-inositol catabolic enzymes and transporter proteins form a tightly linked functional group in a computationally inferred network of protein associations. Primary sequence comparison was not sufficient to confidently extend annotation of all components of this novel metabolic module to related bacterial genera. Consequently, we implemented the Graemlin multiple-network alignment algorithm to generate cross-species predictions of genes involved in myo-inositol transport and catabolism in other alpha-proteobacteria. Although the chromosomal organization of genes in this functional module varied between species, the upstream regions of genes in this aligned network were enriched for the same palindromic cis-regulatory motif identified experimentally in C. crescentus. Transposon disruption of the operon encoding the computationally predicted ABC myo-inositol transporter of Sinorhizobium meliloti abolished growth on myo-inositol as the sole carbon source, confirming our cross-genera functional prediction. Thus, we have defined regulatory, transport, and catabolic genes and a cis-acting regulatory sequence that form a conserved module required for myo

  10. Bacterial assemblages differ between compartments within the coral holobiont

    Science.gov (United States)

    Sweet, M. J.; Croquer, A.; Bythell, J. C.

    2011-03-01

    It is widely accepted that corals are associated with a diverse and host species-specific microbiota, but how they are organized within their hosts remains poorly understood. Previous sampling techniques (blasted coral tissues, coral swabs and milked mucus) may preferentially sample from different compartments such as mucus, tissue and skeleton, or amalgamate them, making comparisons and generalizations between studies difficult. This study characterized bacterial communities of corals with minimal mechanical disruption and contamination from water, air and sediments from three compartments: surface mucus layer (SML), coral tissue and coral skeleton. A novel apparatus (the `snot sucker') was used to separate the SML from tissues and skeleton, and these three compartments were compared to swab samples and milked mucus along with adjacent environmental samples (water column and sediments). Bacterial 16S rRNA gene diversity was significantly different between the various coral compartments and environmental samples (PERMANOVA, F = 6.9, df = 8, P = 0.001), the only exceptions being the complete crushed coral samples and the coral skeleton, which were similar, because the skeleton represents a proportionally large volume and supports a relatively rich microflora. Milked mucus differed significantly from the SML collected with the `snot sucker' and was contaminated with zooxanthellae, suggesting that it may originate at least partially from the gastrovascular cavity rather than the tissue surface. A common method of sampling the SML, surface swabs, produced a bacterial community profile distinct from the SML sampled using our novel apparatus and also showed contamination from coral tissues. Our results indicate that microbial communities are spatially structured within the coral holobiont, and methods used to describe these need to be standardized to allow comparisons between studies.

  11. Disruptive coloration provides camouflage independent of background matching

    OpenAIRE

    Schaefer, H. Martin; Stobbe, Nina

    2006-01-01

    Natural selection shapes the evolution of anti-predator defences, such as camouflage. It is currently contentious whether crypsis and disruptive coloration are alternative mechanisms of camouflage or whether they are interrelated anti-predator defences. Disruptively coloured prey is characterized by highly contrasting patterns to conceal the body shape, whereas cryptic prey minimizes the contrasts to background. Determining bird predation of artificial moths, we found that moths which were di...

  12. Total magnetic reconnection during a tokamak major disruption

    International Nuclear Information System (INIS)

    The safety factor within a tokamak plasma has been measured during a major disruption. During the disruption, the central safety factor jumps from below one to above one, while the total current is unchanged. This implies that total reconnection has occurred. This observation is in contract to the absence of total reconnection observed during a sawtooth oscillation in the same device. 11 refs., 6 figs

  13. Managing Port-Related Supply Chain Disruptions: A Conceptual Paper

    Directory of Open Access Journals (Sweden)

    Hui Shan Loh

    2014-04-01

    This paper synthesizes the current literature into a management model that seeks to target operational deficiencies at ports. The management model is operationalized in three tiers, from the top management level to the front-line employees, with characteristics from risk management, business continuity management and quality management theories. The proposed model serves as a universal guide in assisting port management in managing port-related disruptions and seeks to reduce the occurrences of port-related supply chain disruption threats.

  14. Galaxy Disruption in a Halo of Dark Matter

    OpenAIRE

    Forbes, Duncan; Beasley, Michael; Bekki, Kenji; Brodie, Jean; Strader, Jay

    2003-01-01

    The relics of disrupted satellite galaxies around the Milky Way and Andromeda have been found, but direct evidence of a satellite galaxy in the early stages of being disrupted has remained elusive. We have discovered a dwarf satellite galaxy in the process of being torn apart by gravitational tidal forces as it merges with a larger galaxy's dark matter halo. Our results illustrate the morphological transformation of dwarf galaxies by tidal interaction and the continued build-up of galaxy halos.

  15. Disrupted caring attachments: implications for long-term care.

    Science.gov (United States)

    Flannery, Raymond B

    2002-01-01

    Caring attachments or social supports are the positive psychological and physical contacts and relationships between people. These attachments have been associated with improved health, well-being, and longevity. It is also true that disrupted caring attachments are associated with impaired health and well-being. This paper reviews the general medical and elder medical findings of disrupted caring attachments and negative health outcomes. The implications of these findings for dementia sufferers, caregivers, and long-term care staff are examined.

  16. MOOCs as a disruptive force in online education

    Directory of Open Access Journals (Sweden)

    Dennis Viehland

    Full Text Available MOOCs - massive open online courses - have emerged as the dominant topic in online education in New Zealand and elsewhere. MOOCs have been variously described as a tsunami, a paradigm shift and a disruptive force to both place-based and online tertiary education. This paper offers a comprehensive description of MOOCs and discusses key disruptive aspects of MOOC-based education such as university/student disengagement, low completion rates, peer assessment and business models.

  17. Light pollution disrupts sleep in free-living animals

    OpenAIRE

    Thomas Raap; Rianne Pinxten; Marcel Eens

    2015-01-01

    Artificial lighting can alter individual behaviour, with often drastic and potentially negative effects on biological rhythms, daily activity and reproduction. Whether this is caused by a disruption of sleep, an important widespread behaviour enabling animals to recover from daily stress, is unclear. We tested the hypothesis that light pollution disrupts sleep by recording individual sleep behaviour of great tits, Parus major, that were roosting in dark nest-boxes and were exposed to light-em...

  18. Erosion of plasma-facing materials during a tokamak disruption

    International Nuclear Information System (INIS)

    The behaviour of divertor materials during a major disruption in a tokamak reactor is very important to successful and reliable operation of the device. Erosion of material surfaces due to a thermal energy dump can severely limit the lifetimes of plasma-facing components and thus diminish the reactor's economic feasibility. A comprehensive numerical model has been developed and used in this analysis, which includes all major physical processes taking place during plasma/material interactions. Models to account for material thermal evolution, plasma/vapor interaction physics, and models for hydrodynamic radiation transport in the developed vapor cloud above the exposed surface are implemented in a self-consistent manner to realistically assess disruption damage. The extent of self-protection from the developed vapor cloud in front of the incoming plasma particles is critically important in determining the overall disruption lifetime. Models to study detailed effects of the strong magnetic field on the behaviour of the vapor cloud and on the net erosion rate have also been developed and analyzed. Candidate materials such as beryllium and carbon are considered in this analysis. The dependence of divertor disruption lifetime on disruption physics and reactor conditions is analyzed and discussed. In addition, material erosion from melting of plasma-facing components during a tokamak disruption is also a serious problem that limits reactor operation and economical reactor lifetime. In particular, metallic low-Z components such as Be will be subjected to severe melting during disruptions and edge localized modes (ELMs). Loss of the developed melt layer will critically shorten the lifetime of these components, severely contaminate the plasma, and seriously inhibit successful and reliable operation of the reactor. In this study mechanisms responsible for melt-layer loss during a disruption are also modeled and evaluated. Implications of melt-layer loss on the performance of

  19. The Disruptive Office: Mechanised Furniture to Promote Useful Conflicts

    OpenAIRE

    Boucher, Andy; Law, Andy

    2003-01-01

    This exploratory project investigated the counter-utopian view that conflict can be used as a tool for innovation within collaborative groups. A series of proposals for disruptive office furniture embodied emerging ideas about innovation through conflict. The proposals for Disruptive Office Furniture offer an exaggerated viewpoint on solutions that actively promote innovation and collaboration. They are devised to be brash, outspoken, and confrontational whilst initiating discussion on what t...

  20. North Sea submarine cable disruptions and fishing activity

    OpenAIRE

    Hintzen, N.T.; Machiels, M.A.M.

    2014-01-01

    At the North Sea seafloor, numerous submarine cables are positioned that connect telecommunication networks between countries. Worldwide, human activities cause most of the cable disruptions with fisheries accounting for nearly half of all reported faults. Due to a recent increase of submarine cable disruptions in the central North Sea area, Global Marine Systems Ltd. requested IMARES to investigate a possible link between these occurrences and the recent gear switch of the Dutch –demersal be...

  1. Exploring the relationship between retrieval disruption from collaboration and recall

    OpenAIRE

    Barber, Sarah J.; Rajaram, Suparna

    2011-01-01

    When people recall together in a collaborative group, they recall less than their potential. This phenomenon of collaborative inhibition is explained in terms of retrieval disruption. However, collaborative recall also re-exposes individuals to items recalled by others that they themselves might otherwise have forgotten. This re-exposure produces post-collaborative benefits in individual recall. The current study examined whether reduced retrieval disruption during group recall is related not...

  2. Bacterial chromosome organization and segregation.

    Science.gov (United States)

    Badrinarayanan, Anjana; Le, Tung B K; Laub, Michael T

    2015-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly 1 mm long, approximately 1,000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length scales, highlighting the functions of various DNA-binding proteins and the impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation. PMID:26566111

  3. Bacterial streamers in curved microchannels

    Science.gov (United States)

    Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard

    2009-11-01

    Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.

  4. Bacterial survival in Martian conditions

    CERN Document Server

    D'Alessandro, Giuseppe Galletta; Giulio Bertoloni; Maurizio

    2010-01-01

    We shortly discuss the observable consequences of the two hypotheses about the origin of life on Earth and Mars: the Lithopanspermia (Mars to Earth or viceversa) and the origin from a unique progenitor, that for Earth is called LUCA (the LUCA hypothesis). To test the possibility that some lifeforms similar to the terrestrial ones may survive on Mars, we designed and built two simulators of Martian environments where to perform experiments with different bacterial strains: LISA and mini-LISA. Our LISA environmental chambers can reproduce the conditions of many Martian locations near the surface trough changes of temperature, pressure, UV fluence and atmospheric composition. Both simulators are open to collaboration with other laboratories interested in performing experiments on many kind of samples (biological, minerals, electronic) in situations similar to that of the red planet. Inside LISA we have studied the survival of several bacterial strains and endospores. We verified that the UV light is the major re...

  5. Collective Functionality through Bacterial Individuality

    Science.gov (United States)

    Ackermann, Martin

    According to the conventional view, the properties of an organism are a product of nature and nurture - of its genes and the environment it lives in. Recent experiments with unicellular organisms have challenged this view: several molecular mechanisms generate phenotypic variation independently of environmental signals, leading to variation in clonal groups. My presentation will focus on the causes and consequences of this microbial individuality. Using examples from bacterial genetic model systems, I will first discuss different molecular and cellular mechanisms that give rise to bacterial individuality. Then, I will discuss the consequences of individuality, and focus on how phenotypic variation in clonal populations of bacteria can promote interactions between individuals, lead to the division of labor, and allow clonal groups of bacteria to cope with environmental uncertainty. Variation between individuals thus provides clonal groups with collective functionality.

  6. Carcinogenic effects of circadian disruption: an epigenetic viewpoint.

    Science.gov (United States)

    Salavaty, Abbas

    2015-08-08

    Circadian rhythms refer to the endogenous rhythms that are generated to synchronize physiology and behavior with 24-h environmental cues. These rhythms are regulated by both external cues and molecular clock mechanisms in almost all cells. Disruption of circadian rhythms, which is called circadian disruption, affects many biological processes within the body and results in different long-term diseases, including cancer. Circadian regulatory pathways result in rhythmic epigenetic modifications and the formation of circadian epigenomes. Aberrant epigenetic modifications, such as hypermethylation, due to circadian disruption may be involved in the transformation of normal cells into cancer cells. Several studies have indicated an epigenetic basis for the carcinogenic effects of circadian disruption. In this review, I first discuss some of the circadian genes and regulatory proteins. Then, I summarize the current evidence related to the epigenetic modifications that result in circadian disruption. In addition, I explain the carcinogenic effects of circadian disruption and highlight its potential role in different human cancers using an epigenetic viewpoint. Finally, the importance of chronotherapy in cancer treatment is highlighted.

  7. Bacterial dynamics in intestines of the black tiger shrimp and the Pacific white shrimp during Vibrio harveyi exposure.

    Science.gov (United States)

    Rungrassamee, Wanilada; Klanchui, Amornpan; Maibunkaew, Sawarot; Karoonuthaisiri, Nitsara

    2016-01-01

    The intestinal microbiota play important roles in health of their host, contributing to maintaining the balance and resilience against pathogen. To investigate effects of pathogen to intestinal microbiota, the bacterial dynamics upon a shrimp pathogen, Vibrio harveyi, exposures were determined in two economically important shrimp species; the black tiger shrimp (BT) and the Pacific white shrimp (PW). Both shrimp species were reared under the same diet and environmental conditions. Shrimp survival rates after the V. harveyi exposure revealed that the PW shrimp had a higher resistance to the pathogen than the BT shrimp. The intestinal bacterial profiles were determined by denaturing gradient gel electrophoresis (DGGE) and barcoded pyrosequencing of the 16S rRNA sequences under no pathogen challenge control and under pathogenic V. harveyi challenge. The DGGE profiles showed that the presence of V. harveyi altered the intestinal bacterial patterns in comparison to the control in BT and PW intestines. This implies that bacterial balance in shrimp intestines was disrupted in the presence of V. harveyi. The barcoded pyrosequencing analysis showed the similar bacterial community structures in intestines of BT and PW shrimp under a normal condition. However, during the time course exposure to V. harveyi, the relative abundance of bacteria belong to Vibrio genus was higher in the BT intestines at 12h after the exposure, whereas relative abundance of vibrios was more stable in PW intestines. The principle coordinates analysis based on weighted-UniFrac analysis showed that intestinal bacterial population in the BT shrimp lost their ability to restore their bacterial balance during the 72-h period of exposure to the pathogen, while the PW shrimp were able to reestablish their bacterial population to resemble those seen in the unexposed control group. This observation of bacterial disruption might correlate to different mortality rates observed between the two shrimp species

  8. Bacterial communication and group behavior

    OpenAIRE

    Greenberg, E. Peter

    2003-01-01

    The existence of species-specific and interspecies bacterial cell-cell communication and group organization was only recently accepted. Researchers are now realizing that the ability of these microbial teams to communicate and form structures, known as biofilms, at key times during the establishment of infection significantly increases their ability to evade both host defenses and antibiotics. This Perspective series discusses the known signaling mechanisms, the roles they play in both chroni...

  9. The problem of bacterial diarrhoea.

    Science.gov (United States)

    Harries, J T

    1976-01-01

    The reported incidence of "pathogenic" bacteria, as judged by serotype, in the stools of children with acute diarrhoea has varied from 4 to 33% over the last twenty years. Techniques such as tissue culture provide a means for detecting enterotoxin-producing strains of bacteria, strains which often do not possess "pathogenic" serotypes. "Pathogenicity" requires redefinition, and the aetiological importance of bacteria in diarrhoea is probably considerably greater than previous reports have indicated. Colonization of the bowel by a pathogen will result in structural and/or mucosal abnormalities, and will depend on a series of complex interactions between the external environment, the pathogen, and the host and its resident bacterial flora. Enteropathogenic bacteria may be broadly classified as (i) invasive (e.g. Shigella, Salmonella and some Escherichia coli) which predominantly affect the distal bowel, or (ii) non-invasive (e.g. Vibrio cholerae and E. coli) which affect the proximal bowel. V. cholerae and E. coli elaborate heat-labile enterotoxins which activate adenylate cyclase and induce small intestinal secretion; the secretory effects of heat-stable E. coli and heat-labile Shigella dysenteriae enterotoxins are not accompanied by cyclase activation. The two major complications of acute diarrhoea are (i) hypernatraemic dehydration with its attendant neurological, renal and vascular lesions, and (ii) protracted diarrhoea which may lead to severe malnutrition. Deconjugation of bile salts and colonization of the small bowel with toxigenic strains of E. coli may be important in the pathophysiology of the protracted diarrhoea syndrome. The control of bacterial diarrhoea requires a corrdinated political, educational, social, public health and scientific attack. Bacterial diarrhoea is a major health problem throughout the world, and carries an appreciable morbidity and mortality. This is particularly the case during infancy, and in those developing parts of the world

  10. Bacterial survival in Martian conditions

    OpenAIRE

    Galletta, Giuseppe; Bertoloni, Giulio; D'Alessandro, Maurizio

    2010-01-01

    We shortly discuss the observable consequences of the two hypotheses about the origin of life on Earth and Mars: the Lithopanspermia (Mars to Earth or viceversa) and the origin from a unique progenitor, that for Earth is called LUCA (the LUCA hypothesis). To test the possibility that some lifeforms similar to the terrestrial ones may survive on Mars, we designed and built two simulators of Martian environments where to perform experiments with different bacterial strains: LISA and mini-LISA. ...

  11. Small intestinal bacterial overgrowth syndrome

    Institute of Scientific and Technical Information of China (English)

    Jan; Bures; Jiri; Cyrany; Darina; Kohoutova; Miroslav; Frstl; Stanislav; Rejchrt; Jaroslav; Kvetina; Viktor; Vorisek; Marcela; Kopacova

    2010-01-01

    Human intestinal microbiota create a complex polymi-crobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO).SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastro-intestinal tract. There...

  12. Population dynamics of bacterial persistence

    OpenAIRE

    Patra, Pintu

    2014-01-01

    The life of microorganisms is characterized by two main tasks, rapid growth under conditions permitting growth and survival under stressful conditions. The environments, in which microorganisms dwell, vary in space and time. The microorganisms innovate diverse strategies to readily adapt to the regularly fluctuating environments. Phenotypic heterogeneity is one such strategy, where an isogenic population splits into subpopulations that respond differently under identical environments. Bacteri...

  13. Immunization by a bacterial aerosol

    OpenAIRE

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; DeRousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R.; Miller, Rich; Fourie, P. Bernard; Hickey, Anthony; Edwards, David

    2008-01-01

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried “nanomicroparticle” vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the form...

  14. Rheumatoid arthritis and bacterial infections

    OpenAIRE

    N L Prokopjeva; N N Vesikova; I M Marusenko; V A Ryabkov

    2008-01-01

    To study features of bacterial infections course in pts with rheumatoid arthritis (RA) and changes of laboratory measures after focus of infection sanation. Material and methods. 46 pts with definite rheumatoid arthritis were examined at the time of comorbid infection (Cl) detection and after infection focus sanation. Bacteriological test with evaluation of flora sensitivity to antibiotics by disco-diffusion method was performed at baseline and after the course of antibacterial therapy to ass...

  15. Molecular approaches for bacterial azoreductases

    OpenAIRE

    Montira Leelakriangsak

    2013-01-01

    Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N-) in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study...

  16. Bacterial meningitis by streptococcus agalactiae

    OpenAIRE

    Villarreal-Velásquez Tatiana Paola; Cortés-Daza César Camilo

    2012-01-01

    Introduction: bacterial meningitis is an infectious disease considered a medicalemergency. The timely management has an important impact on the evolution of thedisease. Streptococcus agalactiae, a major causative agent of severe infections innewborns can colonize different tissues, including the central nervous system.Case report: Male patient 47 years old from rural areas, with work activity as amilker of cattle, referred to tertiary care, with disorientation, neck stiffness, and grandmal se...

  17. Bacterial sex in dental plaque

    Directory of Open Access Journals (Sweden)

    Ingar Olsen

    2013-06-01

    Full Text Available Genes are transferred between bacteria in dental plaque by transduction, conjugation, and transformation. Membrane vesicles can also provide a mechanism for horizontal gene transfer. DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. Several examples of bacterial gene transfer in the oral cavity are given in this review. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter- and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes. The ability to transfer DNA is important for bacteria, making them better adapted to the harsh environment of the human mouth, and promoting their survival, virulence, and pathogenicity.

  18. Cytochemical Differences in Bacterial Glycocalyx

    Science.gov (United States)

    Krautgartner, Wolf Dietrich; Vitkov, Ljubomir; Hannig, Matthias; Pelz, Klaus; Stoiber, Walter

    2005-02-01

    To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.

  19. Disruptive Forces Afoot : Prospective Conundrums for Management Consulting - An Explorative Study of Disruptions within the Swedish Industry

    OpenAIRE

    Fhürong, David; Rex, Jonathan

    2015-01-01

    We examine the influence of disruptive forces and innovations on the role of management consultants; specifically how the practitioners themselves interpret changes in fundamental conditions for their profession, later analyzed through the lens of the disruptive innovation theory. With the help of in-depth interviews limited to the Swedish consulting industry, the Big Three traditional strategy consulting firms and the Big Four accounting firms are included in the study, with the aim to study...

  20. Bacterial adhesion and biofilms on surfaces

    Institute of Scientific and Technical Information of China (English)

    Trevor Roger Garrett; Manmohan Bhakoo; Zhibing Zhang

    2008-01-01

    Bacterial adhesion has become a significant problem in industry and in the domicile,and much research has been done for deeper understanding of the processes involved.A generic biological model of bacterial adhesion and population growth called the bacterial biofilm growth cycle,has been described and modified many times.The biofilm growth cycle encompasses bacterial adhesion at all levels,starting with the initial physical attraction of bacteria to a substrate,and ending with the eventual liberation of cell dusters from the biofilm matrix.When describing bacterial adhesion one is simply describing one or more stages of biofilm development,neglecting the fact that the population may not reach maturity.This article provides an overview of bacterial adhesion.cites examples of how bac-terial adhesion affects industry and summarises methods and instrumentation used to improve our understanding of the adhesive prop-erties of bacteria.

  1. Ultrasonic cell disruption of stabilised sludge with subsequent anaerobic digestion.

    Science.gov (United States)

    Onyeche, T I; Schläfer, O; Bormann, H; Schröder, C; Sievers, M

    2002-05-01

    The world-wide increasing environmental awareness and its subsequent regulations have led to the application of improved technologies in wastewater purification plants. This has resulted in higher wastewater and sludge productions. Sludge is the by-product of such plants and it is not only rich in organic carbon and pathogens but also in heavy metals and other environmental pollutants. In Europe, agricultural application of dried sludge (bio-solids) is confronted with negative reactions from the citizens, governmental organisations, farmers and the food industry. Ultrasonic disruption of sludge is a popular mechanical disruption process in sludge treatment. During ultrasonic treatment, high frequency acoustic signals are used to initiate the cavitation process. The applied ultrasonic field leads to a breakdown of cohesive forces of the liquid molecules resulting in the generation of cavitation bubbles. A shock wave is released by the collapse of the cavitation bubbles and propagates in the surrounding medium forming jet streams that cause the disruption of cells in sludge. Disruption of sludge cells enables the release of light organic substances into the sludge water thereby exposing them for further anaerobic digestion. This paper presents results on the disruption of conventionally stabilised sludge through the application of the ultrasonic field. In order to reduce the specific energy input (i.e. ratio of the consumed energy during ultrasonic disruption to the input sludge mass) and improve biogas production, the total solids content of the stabilised sludge was increased before disruption. The anaerobic digestion of sludge samples was carried out in a set of specially constructed laboratory anaerobic digesters. Results showed that subsequent anaerobic digestion of the ultrasonically disrupted sludge could improve biogas production with reduced sludge quantity that is vital to the economic consideration of the wastewater treatment plants. This process

  2. Tidal Decay and Disruption of Short-Period Gaseous Exoplanets

    CERN Document Server

    Jackson, Brian; Peacock, Sarah; Arras, Phil; Penev, Kaloyan

    2016-01-01

    Many gaseous exoplanets in short-period orbits are on the verge or are in the process of tidal disruption. Moreover, orbital stability analysis shows tides can drive many hot Jupiters to spiral toward their host stars. Thus, the coupled processes of orbital evolution and tidal disruption likely shape the observed distribution of close-in exoplanets and may even be responsible for producing some of the short-period rocky planets. However, the exact outcome for a disrupting planet depends on its internal response to mass loss, and the accompanying orbital evolution can act to enhance or inhibit the disruption process. In this study, we apply the fully-featured and robust Modules for Experiments in Stellar Astrophysics (MESA) suite to model Roche-lobe overflow (RLO) of short-period gaseous planets. We show that, although the detailed evolution may depend on several properties of the planetary system, it is largely determined by the core mass of the disrupting gas giant. In particular, we find that the orbital ex...

  3. Disruption mitigation using high pressure gas jets. Final report

    International Nuclear Information System (INIS)

    The goal of this research is to establish credible disruption mitigation scenarios based on the technique of massive gas injection. Disruption mitigation seeks to minimize or eliminate damage to internal components that can occur due to the rapid dissipation of thermal and magnetic energy during a tokamak disruption. In particular, the focus of present research is extrapolating mitigation techniques to burning plasma experiments such as ITER, where disruption-caused damage poses a serious threat to the lifetime of internal vessel components. A majority of effort has focused on national and international collaborative research with large tokamaks: DIII-D, Alcator C-Mod, JET, and ASDEX Upgrade. The research was oriented towards empirical trials of gas-jet mitigation on several tokamaks, with the goal of developing and applying cohesive models to the data across devices. Disruption mitigation using gas jet injection has proven to be a viable candidate for avoiding or minimizing damage to internal components in burning plasma experiments like ITER. The physics understanding is progress towards a technological design for the required gas injection system in ITER.

  4. Effects of vimentin disruption on the mechanoresponses of articular chondrocyte.

    Science.gov (United States)

    Chen, Cheng; Yin, Li; Song, Xiongbo; Yang, Hao; Ren, Xiang; Gong, Xiaoyuan; Wang, Fuyou; Yang, Liu

    2016-01-01

    Human articular cartilage is subjected to repetitive mechanical loading during life time. As the only cellular component of articular cartilage, chondrocytes play a key role in the mechanotransduction within this tissue. The mechanoresponses of chondrocytes are largely determined by the cytoskeleton. Vimentin intermediate filaments, one of the major cytoskeletal components, have been shown to regulate chondrocyte phenotype. However, the contribution of vimentin in chondrocyte mechanoresponses remains less studied. In this study, we seeded goat articular chondrocytes on a soft polyacrylamide gel, and disrupted the vimentin cytoskeleton using acrylamide. Then we applied a transient stretch or compression to the cells, and measured the changes of cellular stiffness and traction forces using Optical Magnetic Twisting Cytometry and Traction Force Microscopy, respectively. In addition, to study the effects of vimentin disruption on the intracellular force generation, we treated the cells with a variety of reagents that are known to increase or decrease cytoskeletal tension. We found that, after a compression, the contractile moment and cellular stiffness were not affected in untreated chondrocytes, but were decreased in vimentin-disrupted chondrocytes; after a stretch, vimentin-disrupted chondrocytes showed a lower level of fluidization-resolidification response compared to untreated cells. Moreover, vimentin-disrupted chondrocytes didn't show much difference to control cells in responding to reagents that target actin and ROCK pathway, but showed a weaker response to histamine and isoproterenol. These findings confirmed chondrocyte vimentin as a major contributor in withstanding compressive loading, and its minor role in regulating cytoskeletal tension. PMID:26616052

  5. Disruption avoidance through active magnetic feedback in tokamak plasmas

    Science.gov (United States)

    Paccagnella, Roberto; Zanca, Paolo; Yanovskiy, Vadim; Finotti, Claudio; Manduchi, Gabriele; Piron, Chiara; Carraro, Lorella; Franz, Paolo; RFX Team

    2014-10-01

    Disruptions avoidance and mitigation is a fundamental need for a fusion relevant tokamak. In this paper a new experimental approach for disruption avoidance using active magnetic feedback is presented. This scheme has been implemented and tested on the RFX-mod device operating as a circular tokamak. RFX-mod has a very complete system designed for active mode control that has been proved successful for the stabilization of the Resistive Wall Modes (RWMs). In particular the current driven 2/1 mode, unstable when the edge safety factor, qa, is around (or even less than) 2, has been shown to be fully and robustly stabilized. However, at values of qa (qa > 3), the control of the tearing 2/1 mode has been proved difficult. These results suggested the idea to prevent disruptions by suddenly lowering qa to values around 2 where the tearing 2/1 is converted to a RWM. Contrary to the universally accepted idea that the tokamaks should disrupt at low qa, we demonstrate that in presence of a well designed active control system, tokamak plasmas can be driven to low qa actively stabilized states avoiding plasma disruption with practically no loss of the plasma internal energy.

  6. Opiskelijoiden välinen vuorovaikutus : Satakunnan ammattikorkeakoulun 2. vuoden opiskelijat, Porin tekniikka, Porin liiketoiminta ja Porin hoitotyö

    OpenAIRE

    Kukkula, Pauliina

    2010-01-01

    Tämän opinnäytetyön tarkoituksena oli selvittää Satakunnan ammattikorkeakoulun 2. vuoden opiskelijoiden välistä vuorovaikutusta. Tavoitteena oli saada tietoa Satakunnan ammattikorkeakoulun opiskelijoiden välisestä vuorovaikutuksesta ja siihen mahdollisesti liittyvästä kiusaamisesta Satakunnan ammattikorkeakoulussa. Opinnäytetyön aihe valittiin Satakunnan ammattikorkeakoulun sosiaali- ja terveysalan opinnäytetöiden aihepankista. Tämä aihe oli opinnäytetyön tekijän mielestä mielenkiintoine...

  7. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

    Science.gov (United States)

    Shi, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-06-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection. PMID:26948237

  8. Wavelet to predict bacterial ori and ter: a tendency towards a physical balance

    Directory of Open Access Journals (Sweden)

    Ware Antony

    2003-05-01

    Full Text Available Abstract Background Chromosomal DNA replication in bacteria starts at the origin (ori and the two replicores propagate in opposite directions up to the terminus (ter region. We hypothesize that the two replicores need to reach ter at the same time to maintain a physical balance; DNA insertion would disrupt such a balance, requiring chromosomal rearrangements to restore the balance. To test this hypothesis, we needed to demonstrate that ori and ter are in a physical balance in bacterial chromosomes. Using wavelet analysis, we documented GC skew, AT skew, purine excess and keto excess on the published bacterial genomic sequences to locate the turning (minimum and maximum points on the curves. Previously, the minimum point had been supposed to correlate with ori and the maximum to correlate with ter. Results We observed a strong tendency of the bacterial chromosomes towards a physical balance, with the minima and maxima corresponding to the known or putative ori and ter and being about half chromosome separated in most of the bacteria studied. A nonparametric method based on wavelet transformation was employed to perform significance tests for the predicted loci. Conclusions The wavelet approach can reliably predict the ori and ter regions and the bacterial chromosomes have a strong tendency towards a physical balance between ori and ter.

  9. Control of Postharvest Bacterial Soft Rot by Gamma Irradiation and its Potential Modes of Action

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2016-04-01

    Full Text Available Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc. Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

  10. A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing.

    Science.gov (United States)

    Ismail, Anisa S; Valastyan, Julie S; Bassler, Bonnie L

    2016-04-13

    Host-microbial symbioses are vital to health; nonetheless, little is known about the role crosskingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote interspecies bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering crosskingdom signaling and host-bacterial symbioses.

  11. Electromagnetic study on HCCR TBM for ITER major disruption scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Duck Young; Lee, Youngmin; Cho, Seungyon; Ahn, Muyoung [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) has been developed in Korea in order to experiment a breeding blanket module in ITER. This TBM will verify the feasibility of tritium self-sufficiency in reactor and the extraction of high-grade heat suitable for electricity generation. Since various loads such as seismic load, electromagnetic (EM) load and heat load significantly affect the soundness of the TBM, a variety of analyses were carried out for design optimization. The EM load is particularly one of main design drivers because large amount of magnetic energy in the plasma are transferred to in-vessel components including the TBM during plasma disruption. Because the TBM is located in equatorial port, major disruption (MD) among various plasma disruption scenarios causes the largest EM loads on the TBM.

  12. Status of research toward the ITER disruption mitigation system

    Energy Technology Data Exchange (ETDEWEB)

    Hollmann, E. M.; Izzo, V. A. [Center for Energy Research, University of California, San Diego, La Jolla, California 92093-0417 (United States); Aleynikov, P. B.; Lehnen, M.; Snipes, J. A. [ITER Organization, Route de Vinon sur Verdon, CS 90 046 - 13067 Saint Paul lez Durance (France); Fülöp, T. [Department of Applied Physics, Chalmers University of Technology, Göteborg (Sweden); Humphreys, D. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Lukash, V. E. [Institute of Nuclear Fusion, RRC Kurchatov Institute, Moscow (Russian Federation); Papp, G.; Pautasso, G. [Max-Planck Institute for Plasma Physics, EURATOM Association, Garching (Germany); Saint-Laurent, F. [CEA, IRFM, Saint Paul lez Durance (France)

    2015-02-15

    An overview of the present status of research toward the final design of the ITER disruption mitigation system (DMS) is given. The ITER DMS is based on massive injection of impurities, in order to radiate the plasma stored energy and mitigate the potentially damaging effects of disruptions. The design of this system will be extremely challenging due to many physics and engineering constraints such as limitations on port access and the amount and species of injected impurities. Additionally, many physics questions relevant to the design of the ITER disruption mitigation system remain unsolved such as the mechanisms for mixing and assimilation of injected impurities during the rapid shutdown and the mechanisms for the subsequent formation and dissipation of runaway electron current.

  13. Disruptions and halo currents in Alcator C-Mod

    Science.gov (United States)

    Granetz, R. S.; Hutchinson, I. H.; Sorci, J.; Irby, J. H.; La Bombard, B.; Gwinn, D.

    1996-05-01

    Disruptions in Alcator C-Mod can generate large eddy currents in the highly conducting vacuum vessel and internal structures, including a significant poloidal component due to halo currents. In order to understand better the stresses arising from the resulting J*B forces, Alcator C-Mod has been fitted with a comprehensive set of sensors to measure the spatial distribution and temporal behaviour of the halo currents. It is found that they are toroidally asymmetric, with a typical peaking factor of 2. The asymmetric pattern usually rotates toroidally at a few kilohertz, thus ruling out first wall non-uniformities as the cause of the asymmetry. Analysis of the information compiled in the C-Mod disruption database indicates that the maximum halo current during a disruption scales roughly as either Ip2/Bphi or Ip/q95, but that there is a large amount of variation that is not yet understood

  14. Extinction order and altered community structure rapidly disrupt ecosystem functioning.

    Science.gov (United States)

    Larsen, Trond H; Williams, Neal M; Kremen, Claire

    2005-05-01

    By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences.

  15. Designing a Supply Chain Network under the Risk of Disruptions

    Directory of Open Access Journals (Sweden)

    Armin Jabbarzadeh

    2012-01-01

    Full Text Available This paper studies a supply chain design problem with the risk of disruptions at facilities. At any point of time, the facilities are subject to various types of disruptions caused by natural disasters, man-made defections, and equipment breakdowns. We formulate the problem as a mixed-integer nonlinear program which maximizes the total profit for the whole system. The model simultaneously determines the number and location of facilities, the subset of customers to serve, the assignment of customers to facilities, and the cycle-order quantities at facilities. In order to obtain near-optimal solutions with reasonable computational requirements for large problem instances, two solution methods based on Lagrangian relaxation and genetic algorithm are developed. The effectiveness of the proposed solution approaches is shown using numerical experiments. The computational results, in addition, demonstrate that the benefits of considering disruptions in the supply chain design model can be significant.

  16. A new approach for disruption management in airline operations control

    CERN Document Server

    Castro, António J M; Oliveira, Eugénio

    2014-01-01

    Most of the research efforts dealing with airline scheduling have been done on off-line plan optimization.  However, nowadays, with the increasingly complex and huge traffic at airports, the real challenge is how to react to unexpected events that may cause plan-disruptions, leading to flight delays. Moreover these disruptive events usually affect at least three different dimensions of the situation: the aircraft assigned to the flight, the crew assignment and, often forgotten, the passengers’ journey and satisfaction. This book includes answers to this challenge and proposes the use of the Multi-agent System paradigm to rapidly compose a multi-faceted solution to the disruptive event taking into consideration possible preferences of those three key aspects of the problem. Negotiation protocols taking place between agents that are experts in solving the different problem dimensions, combination of different utility functions and, not less important, the inclusion of the human in the automatic decision-maki...

  17. Disrupted Functional Connectivity with Dopaminergic Midbrain in Cocaine Abusers

    Energy Technology Data Exchange (ETDEWEB)

    Tomasi, D.; Tomasi, D.; Volkow, N.D.; Wang, R.; Carrillo, J.; Maloney, T.; Alia-Klein, N.; Woicik, P.A.; Telang, F.; Goldstein, R.Z.

    2010-06-01

    Chronic cocaine use is associated with disrupted dopaminergic neurotransmission but how this disruption affects overall brain function (other than reward/motivation) is yet to be fully investigated. Here we test the hypothesis that cocaine addicted subjects will have disrupted functional connectivity between the midbrain (where dopamine neurons are located) and cortical and subcortical brain regions during the performance of a sustained attention task. We measured brain activation and functional connectivity with fMRI in 20 cocaine abusers and 20 matched controls. When compared to controls, cocaine abusers had lower positive functional connectivity of midbrain with thalamus, cerebellum, and rostral cingulate, and this was associated with decreased activation in thalamus and cerebellum and enhanced deactivation in rostral cingulate. These findings suggest that decreased functional connectivity of the midbrain interferes with the activation and deactivation signals associated with sustained attention in cocaine addicts.

  18. Disrupted functional connectivity with dopaminergic midbrain in cocaine abusers.

    Directory of Open Access Journals (Sweden)

    Dardo Tomasi

    Full Text Available BACKGROUND: Chronic cocaine use is associated with disrupted dopaminergic neurotransmission but how this disruption affects overall brain function (other than reward/motivation is yet to be fully investigated. Here we test the hypothesis that cocaine addicted subjects will have disrupted functional connectivity between the midbrain (where dopamine neurons are located and cortical and subcortical brain regions during the performance of a sustained attention task. METHODOLOGY/PRINCIPAL FINDINGS: We measured brain activation and functional connectivity with fMRI in 20 cocaine abusers and 20 matched controls. When compared to controls, cocaine abusers had lower positive functional connectivity of midbrain with thalamus, cerebellum, and rostral cingulate, and this was associated with decreased activation in thalamus and cerebellum and enhanced deactivation in rostral cingulate. CONCLUSIONS/SIGNIFICANCE: These findings suggest that decreased functional connectivity of the midbrain interferes with the activation and deactivation signals associated with sustained attention in cocaine addicts.

  19. Periodontal diseases as bacterial infection

    Directory of Open Access Journals (Sweden)

    A. Bascones Martínez

    2005-12-01

    Full Text Available The periodontal disease is conformed by a group of illnesses affecting the gums and dental support structures. They are caused by certain bacteria found in the bacterial plaque. These bacteria are essential to the onset of illness; however, there are predisposing factors in both the host and the microorganisms that will have an effect on the pathogenesis of the illness. Periodontopathogenic bacterial microbiota is needed, but by itself, it is not enough to cause the illness, requiring the presence of a susceptible host. These diseases have been classified as gingivitis, when limited to the gums, and periodontitis, when they spread to deeper tissues. Classification of periodontal disease has varied over the years.The one used in this work was approved at the International Workshop for a Classification of Periodontal Diseases and Conditions, held in 1999. This study is an overview of the different periodontal disease syndromes. Later, the systematic use of antibiotic treatment consisting of amoxicillin, amoxicillinclavulanic acid, and metronidazole as first line coadjuvant treatment of these illnesses will be reviewed.

  20. Bacterial mutagenicity assays: test methods.

    Science.gov (United States)

    Gatehouse, David

    2012-01-01

    The most widely used assays for detecting chemically induced gene mutations are those employing bacteria. The plate incorporation assay using various Salmonella typhimurium LT2 and E. coli WP2 strains is a short-term bacterial reverse mutation assay specifically designed to detect a wide range of chemical substances capable of causing DNA damage leading to gene mutations. The test is used worldwide as an initial screen to determine the mutagenic potential of new chemicals and drugs.The test uses several strains of S. typhimurium which carry different mutations in various genes of the histidine operon, and E. coli which carry the same AT base pair at the critical mutation site within the trpE gene. These mutations act as hot spots for mutagens that cause DNA damage via different mechanisms. When these auxotrophic bacterial strains are grown on a minimal media agar plates containing a trace of the required amino-acid (histidine or tryptophan), only those bacteria that revert to amino-acid independence (His(+) or Tryp(+)) will grow to form visible colonies. The number of spontaneously induced revertant colonies per plate is relatively constant. However, when a mutagen is added to the plate, the number of revertant colonies per plate is increased, usually in a dose-related manner.This chapter provides detailed procedures for performing the test in the presence and absence of a metabolic activation system (S9-mix), including advice on specific assay variations and any technical problems. PMID:22147566

  1. BACTERIAL DESEASES IN SEA FISH

    Directory of Open Access Journals (Sweden)

    Ivančica Strunjak-Perović

    1997-10-01

    Full Text Available With development of the fish culturing in the sea, the interest in their health also increased. The reason for this are diseases or rather mortality that occur in such controlled cultures and cause great economic losses. By growing large quantities of fish in rather small species, natural conditions are changed, so fish is more sensitive and prone to infection agents (viruses, bacteria, parasites. Besides, a large fish density in the cultural process accelerates spreading if the diseases, but also enables a better perception of them. In wild populations sick specimen very quickly become predator’s prey, witch makes it difficult to note any pathological changes in such fish. There are lots of articles on viral, bacterial and parasitic diseases nowdays, but this work deals exclusively with bacterial deseases that occur in the controlled sea cultures (vibriosis, furunculosis, pastherelosis, nocardiosis, mycobaceriosis, edwardsielosis, yersiniosis, deseases caused by bacteria of genera Flexibacter, Pseudomonas, Aeromonas, Streptococus and bacteria nephryithis. Yet, the knowledge of these deseases vary, depending on wether a fish species is being cultured for a longer period of time or is only being introduced in the controlled culture.

  2. Bioinformatic Comparison of Bacterial Secretomes

    Institute of Scientific and Technical Information of China (English)

    Catharine Song; Aseem Kumar; Mazen Saleh

    2009-01-01

    The rapid increasing number of completed bacterial genomes provides a good op-portunity to compare their proteomes. This study was undertaken to specifically compare and contrast their secretomes-the fraction of the proteome with pre-dicted N-terminal signal sequences, both type Ⅰ and type Ⅱ. A total of 176 theoreti-cal bacterial proteomes were examined using the ExProt program. Compared with the Gram-positives, the Gram-negative bacteria were found, on average, to con-tain a larger number of potential Sec-dependent sequences. In the Gram-negative bacteria but not in the others, there was a positive correlation between proteome size and secretome size, while there was no correlation between secretome size and pathogenicity. Within the Gram-negative bacteria, intracellular pathogens were found to have the smallest secretomes. However, the secretomes of certain bacte-ria did not fit into the observed pattern. Specifically, the secretome of Borrelia burgdoferi has an unusually large number of putative lipoproteins, and the signal peptides of mycoplasmas show closer sequence similarity to those of the Gram-negative bacteria. Our analysis also suggests that even for a theoretical minimal genome of 300 open reading frames, a fraction of this gene pool (up to a maximum of 20%) may code for proteins with Sec-dependent signal sequences.

  3. Bacterial Culture of Neonatal Sepsis

    Directory of Open Access Journals (Sweden)

    AH Movahedian

    2006-08-01

    Full Text Available Neonatal bacterial sepsis is one of the major cause of morbidity and mortality in neonates. This retrospective study was performed to determine the incidence of bacterial sepsis with focus on Gram negative organisms in neonates admitted at Beheshti Hospital in Kashan, during a 3-yr period, from September 2002 to September 2005. Blood culture was performed on all neonates with risk factors or signs of suggestive sepsis. Blood samples were cultured using brain heart infusion (BHI broth according to standard method. From the 1680 neonates 36% had positive blood culture for Pseudomans aeruginosa, 20.7% for Coagulase negative Staphylococci, and 17% for Klebsiella spp. Gram-negative organisms accounted for 72.1% of all positive cultures. The overall mortality rate was 19.8% (22 /111 of whom 63.6% (14 /22 were preterm. Pseudomona aeruginosa and Klebsiella spp. showed a high degree of resistance to commonly used antibiotics (ampicillin, gentamicin as well as third generation cephalosporins. Continued local surveillance studies are urged to monitor emerging antimicrobial resistance and to guide interventions to minimize its occurrence.

  4. Immunization by a bacterial aerosol.

    Science.gov (United States)

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; Derousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R; Miller, Rich; Fourie, P Bernard; Hickey, Anthony; Edwards, David

    2008-03-25

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried "nanomicroparticle" vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow. Particles formed with this combination of nano- and micrometer-scale dimensions possess a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. Here, we demonstrate effective application of this biomaterial by using the live attenuated tuberculosis vaccine bacille Calmette-Guérin (BCG). Prepared as a spray-dried nanomicroparticle aerosol, BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system. Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG. PMID:18344320

  5. Learning in disrupted projects: on the nature of corporate and personal learning

    OpenAIRE

    Howick, Susan; Eden, Colin

    2007-01-01

    Abstract The majority of large, complex projects suffer disruptions. These can have unexpected and significant impacts on a project, resulting in excessive time and cost overruns. Disrupted projects therefore require careful management in order to minimise the impact of a disruption. One element of a project for which disruptions will have a particular impact is on any anticipated learning gains. Loss of learning from disruptions can often be very significant. This lost learning ma...

  6. Disruptive change. When trying harder is part of the problem.

    Science.gov (United States)

    Gilbert, Clark; Bower, Joseph L

    2002-05-01

    When a company faces a major disruption in its markets, managers' perceptions of the disruption influence how they respond to it. If, for instance, they view the disruption as a threat to their core business, managers tend to overreact, committing too many resources too quickly. But if they see it as an opportunity, they're likely to commit insufficient resources to its development. Clark Gilbert and Joseph Bower explain why thinking in such stark terms--threat or opportunity--is dangerous. It's possible, they argue, to arrive at an organizational framing that makes good use of the adrenaline a threat creates as well as of the creativity an opportunity affords. The authors claim that the most successful companies frame the challenge differently at different times: When resources are being allocated, managers see the disruptive innovation as a threat. But when the hard strategic work of discovering and responding to new markets begins, the disruptive innovation is treated as an opportunity. The ability to reframe the disruptive technology as circumstances evolve is not an easy skill to master, the authors admit. In fact, it might not be possible without adjusting the organizational structure and the processes governing new business funding. Successful companies, the authors have determined, tend to do certain things: They establish a new venture separate from the core business; they fund the venture in stages as markets emerge; they don't rely on employees from the core organization to staff the new business; and they appoint an active integrator to manage the tensions between the two organizations, to name a few. This article will help executives frame innovations in more balanced ways--allowing them to recognize threats but also to seize opportunities. PMID:12024762

  7. Remodeling bacterial polysaccharides by metabolic pathway engineering

    OpenAIRE

    Yi, Wen; Liu, Xianwei; Li, Yanhong; Li, Jianjun; Xia, Chengfeng; Zhou, Guangyan; Zhang, Wenpeng; Zhao, Wei; Chen, Xi; Wang, Peng George

    2009-01-01

    Introducing structural modifications into biomolecules represents a powerful approach to dissect their functions and roles in biological processes. Bacterial polysaccharides, despite their rich structural information and essential roles in bacterium-host interactions and bacterial virulence, have largely been unexplored for in vivo structural modifications. In this study, we demonstrate the incorporation of a panel of monosaccharide analogs into bacterial polysaccharides in a highly homogenou...

  8. Effect of aerosolization on subsequent bacterial survival.

    OpenAIRE

    Walter, M V; Marthi, B; Fieland, V P; Ganio, L M

    1990-01-01

    To determine whether aerosolization could impair bacterial survival, Pseudomonas syringae and Erwinia herbicola were aerosolized in a greenhouse, the aerosol was sampled at various distances from the site of release by using all-glass impingers, and bacterial survival was followed in the impingers for 6 h. Bacterial survival subsequent to aerosolization of P. syringae and E. herbicola was not impaired 1 m from the site of release. P. syringae aerosolized at 3 to 15 m from the site of release ...

  9. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Ogata, Satoshi; Numakawa, Tetsuya; Kubo, Takuya

    2010-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  10. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Satoshi Ogata; Tetsuya Numakawa; Takuya Kubo

    2011-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  11. Designing Endocrine Disruption Out of the Next Generation of Chemicals

    OpenAIRE

    Schug, T. T.; Abagyan, R; Blumberg, B; Collins, T J; Crews, D.; DeFur, P.L.; Dickerson, S.M.; Edwards, T.M.; Gore, A.C.; Guillette, L J; Hayes, T.; Heindel, J J; Moores, A.; Patisaul, H.B.; Tal, T.L.

    2013-01-01

    A central goal of green chemistry is to avoid hazard in the design of new chemicals. This objective is best achieved when information about a chemical’s potential hazardous effects is obtained as early in the design process as feasible. Endocrine disruption is a type of hazard that to date has been inadequately addressed by both industrial and regulatory science. To aid chemists in avoiding this hazard, we propose an endocrine disruption testing protocol for use by chemists in the design of n...

  12. Summary 14 leadership principles behind the world's most disruptive company

    CERN Document Server

    2015-01-01

    Complete summary of John Rossman's book: ""The Amazon Way: 14 Leadership Principles Behind the World's Most Disruptive Company""This summary of ideas from John Rossman's book ""The Amazon Way: 14 Leadership Principles Behind the World's Most Disruptive Company"" reveals the leadership 'secrets' behind one of the biggest companies in the world. These 'secrets' are applied to all decision-making processes in the business and are used every day.There are 14 principles of leadership:1. Obsess over the customer2. Take ownership of results3. Invent and simplify4. Leaders are right - A lot5. Hire an

  13. Biomarkers used in Environmental Health with focus on Endocrine Disrupters

    DEFF Research Database (Denmark)

    Krüger, Tanja; Ghisari, Mandana; Long, Manhai;

    2012-01-01

    Endocrine-disrupting chemicals (EDCs) are compounds that either mimic or block endogenous hormones and can disrupt the normal function of the body. Bio-monitoring is the assessment of internal doses of EDCs and has been used for decades to provide information about exposures to chemicals giving...... in human blood is important and ex vivo cell systems have been introduced to enable the assessment of the integrated level of xenobiotic transactivity in humans. Biomonitoring studies for exposure biomarkers have shown that there are geographical differences in the bioaccumulated POP levels...

  14. Testicular dysgenesis syndrome: possible role of endocrine disrupters

    DEFF Research Database (Denmark)

    Bay, Katrine; Asklund, Camilla; Skakkebaek, Niels E;

    2006-01-01

    molecular studies, all suggestive of an interrelation between the different symptoms. The aetiology of TDS is suspected to be related to genetic and/or environmental factors, including endocrine disrupters. Few human studies have found associations/correlations between endocrine disrupters, including...... phthalates, and the different TDS components. However, for ethical reasons, evidence of a causal relationship between prenatal exposure and TDS is inherently difficult to establish in human studies, rendering the recently developed animal TDS model an important tool for investigating the pathogenesis of TDS...

  15. Disruption Management in Passenger Transportation - from Air to Tracks

    DEFF Research Database (Denmark)

    Clausen, Jens

    2007-01-01

    of the world has show a dramatic increase as well. Public transportation by e.g. rail has come into focus, and hence also the service level provided by suppliers ad public transportation. These transportation systems are likewise very vulnerable to disruptions. In the airline industry there is a long tradition...... operations are becoming available. The use of advanced planning and recovery methods in the railway industry currently gains momentum. The current paper gives a short overview over the methods used for planning and disruption management in the airline industry. The situation regarding railway optimization...

  16. Exposure to endocrine disrupting chemicals and neurodevelopmental alterations.

    Science.gov (United States)

    Pinson, A; Bourguignon, J P; Parent, A S

    2016-07-01

    The developing brain is remarkably malleable as neural circuits are formed and these circuits are strongly dependent on hormones for their development. For those reasons, the brain is very vulnerable to the effects of endocrine-disrupting chemicals (EDCs) during critical periods of development. This review focuses on three ubiquitous endocrine disruptors that are known to disrupt the thyroid function and are associated with neurobehavioral deficits: polychlorinated biphenyls, polybrominated diphenyl ethers, and bisphenol A. The human and rodent data suggesting effects of those EDCs on memory, cognition, and social behavior are discussed. Their mechanisms of action go beyond relative hypothyroidism with effects on neurotransmitter release and calcium signaling. PMID:27285165

  17. Bacterial successions in the Broiler Gastrointestinal tract

    DEFF Research Database (Denmark)

    Ranjitkar, Samir; Lawley, Blair; Tannock, Gerald;

    2016-01-01

    of crop, gizzard, ileum and ceca in relation to the feeding strategy and age (8, 15, 22, 25, 29 and 36 days). Of the four dietary treatments, bacterial diversity was analyzed for MBF and CKMS-30 by 454-pyrosequencing of 16S rRNA gene. Since there was no significant influence of diets on bacterial...... diversity, data were pooled for downstream analysis. With increasing age, a clear succession of bacterial communities and an increased bacterial diversity was observed. Lactobacillaceae (mainly Lactobacillus) represented most of the Firmicutes at all ages and in all segments of the gut except the ceca...

  18. Small RNAs controlling outer membrane porins

    DEFF Research Database (Denmark)

    Valentin-Hansen, Poul; Johansen, Jesper; Rasmussen, Anders A

    2007-01-01

    Gene regulation by small non-coding RNAs has been recognized as an important post-transcriptional regulatory mechanism for several years. In Gram-negative bacteria such as Escherichia coli and Salmonella, these RNAs control stress response and translation of outer membrane proteins and therefore...

  19. Effect of heavy metals on bacterial transport

    Science.gov (United States)

    Zhang, H.; Olson, M. S.

    2010-12-01

    Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavy metals. The adsorption of heavy metals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (α) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (α) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(α 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavy metals seems to

  20. Autoproteolytic Activation of Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Aimee Shen

    2010-05-01

    Full Text Available Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD in Multifunctional Autoprocessing RTX-like (MARTX and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6, which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.