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Sample records for bacterially induced precipitation

  1. Bacterially induced precipitation of CaCO sub 3 : An example from studies of cyanobacterial mats

    SciTech Connect

    Chafetz, H.S.

    1990-04-30

    Bacteria induce the precipitation of calcium carbonate in the laboratory and in nature by altering their chemical environment. Geologists are recognizing the possibility that bacterially induced precipitates may form significant mineral deposits, unfortunately, there are currently no sound criteria by which they can be recognized in recent sediments, or in the rock record. Cultures of aerobic and facultative bacteria from cyanobacterial mats on Andros Island, Bahamas, and Baffin Bay, Texas, induced the precipitation of calcium carbonate under controlled conditions. Crusts, the largest features formed, are composed of 5--200{mu}m diameter bundles which are, in turn, composed of numerous individual crystals. The smallest observed features are 0.1--0.4{mu}m spheres and rods which comprise some individual crystals and crystal bundles. Crystal bundles resembling rhombohedra, tetragonal disphenoids, tetragonal dipyramids, and calcite dumbbells appear to be uniquely bacterial in origin, and they have all been observed in recent sediments. Swollen rods, discs, curved dumbbells, and 50--200{mu}m optically continuous crystals resembling brushes may be uniquely bacterial in origin, however, they have not been reported by other laboratories nor observed in natural settings. Presence of any of these forms in recent sediments should be taken as strong evidence for bacterial influence. Spheres and aragonite dumbbells have also been observed in natural environments, however, they are not always bacterial in origin. Precipitation of calcium carbonate occurs preferentially on dead cyanobacteria in the presence of bacteria. Lithification of algal mats to form stromatolites may take place in the zone of decaying organic matter due to bacterial activity.

  2. Bacterially induced precipitation of CaCO{sub 3}: An example from studies of cyanobacterial mats. Final report

    SciTech Connect

    Chafetz, H.S.

    1990-04-30

    Bacteria induce the precipitation of calcium carbonate in the laboratory and in nature by altering their chemical environment. Geologists are recognizing the possibility that bacterially induced precipitates may form significant mineral deposits, unfortunately, there are currently no sound criteria by which they can be recognized in recent sediments, or in the rock record. Cultures of aerobic and facultative bacteria from cyanobacterial mats on Andros Island, Bahamas, and Baffin Bay, Texas, induced the precipitation of calcium carbonate under controlled conditions. Crusts, the largest features formed, are composed of 5--200{mu}m diameter bundles which are, in turn, composed of numerous individual crystals. The smallest observed features are 0.1--0.4{mu}m spheres and rods which comprise some individual crystals and crystal bundles. Crystal bundles resembling rhombohedra, tetragonal disphenoids, tetragonal dipyramids, and calcite dumbbells appear to be uniquely bacterial in origin, and they have all been observed in recent sediments. Swollen rods, discs, curved dumbbells, and 50--200{mu}m optically continuous crystals resembling brushes may be uniquely bacterial in origin, however, they have not been reported by other laboratories nor observed in natural settings. Presence of any of these forms in recent sediments should be taken as strong evidence for bacterial influence. Spheres and aragonite dumbbells have also been observed in natural environments, however, they are not always bacterial in origin. Precipitation of calcium carbonate occurs preferentially on dead cyanobacteria in the presence of bacteria. Lithification of algal mats to form stromatolites may take place in the zone of decaying organic matter due to bacterial activity.

  3. Bacterially induced calcium carbonate precipitation and strontium coprecipitation in a porous media flow system.

    PubMed

    Lauchnor, Ellen G; Schultz, Logan N; Bugni, Steven; Mitchell, Andrew C; Cunningham, Alfred B; Gerlach, Robin

    2013-02-05

    Strontium-90 is a principal radionuclide contaminant in the subsurface at several Department of Energy sites in the Western U.S., causing a threat to groundwater quality in areas such as Hanford, WA. In this work, we used laboratory-scale porous media flow cells to examine a potential remediation strategy employing coprecipitation of strontium in carbonate minerals. CaCO(3) precipitation and strontium coprecipitation were induced via ureolysis by Sporosarcina pasteurii in two-dimensional porous media reactors. An injection strategy using pulsed injection of calcium mineralization medium was tested against a continuous injection strategy. The pulsed injection strategy involved periods of lowered calcite saturation index combined with short high fluid velocity flow periods of calcium mineralization medium followed by stagnation (no-flow) periods to promote homogeneous CaCO(3) precipitation. By alternating the addition of mineralization and growth media the pulsed strategy promoted CaCO(3) precipitation while sustaining the ureolytic culture over time. Both injection strategies achieved ureolysis with subsequent CaCO(3) precipitation and strontium coprecipitation. The pulsed injection strategy precipitated 71-85% of calcium and 59% of strontium, while the continuous injection was less efficient and precipitated 61% of calcium and 56% of strontium. Over the 60 day operation of the pulsed reactors, ureolysis was continually observed, suggesting that the balance between growth and precipitation phases allowed for continued cell viability. Our results support the pulsed injection strategy as a viable option for ureolysis-induced strontium coprecipitation because it may reduce the likelihood of injection well accumulation caused by localized mineral plugging while Sr coprecipitation efficiency is maintained in field-scale applications.

  4. Monitoring bacterially induced calcite precipitation in porous media using magnetic resonance imaging and flow measurements.

    PubMed

    Sham, E; Mantle, M D; Mitchell, J; Tobler, D J; Phoenix, V R; Johns, M L

    2013-09-01

    A range of nuclear magnetic resonance (NMR) techniques are employed to provide novel, non-invasive measurements of both the structure and transport properties of porous media following a biologically mediated calcite precipitation reaction. Both a model glass bead pack and a sandstone rock core were considered. Structure was probed using magnetic resonance imaging (MRI) via a combination of quantitative one-dimensional profiles and three-dimensional images, applied before and after the formation of calcite in order to characterise the spatial distribution of the precipitate. It was shown through modification and variations of the calcite precipitation treatment that differences in the calcite fill would occur but all methods were successful in partially blocking the different porous media. Precipitation was seen to occur predominantly at the inlet of the bead pack, whereas precipitation occurred almost uniformly along the sandstone core. Transport properties are quantified using pulse field gradient (PFG) NMR measurements which provide probability distributions of molecular displacement over a set observation time (propagators), supplementing conventional permeability measurements. Propagators quantify the local effect of calcite formation on system hydrodynamics and the extent of stagnant region formation. Collectively, the combination of NMR measurements utilised here provides a toolkit for determining the efficacy of a biological-precipitation reaction for partially blocking porous materials.

  5. Soil bacterial community structure responses to precipitation reduction and forest management in forest ecosystems across Germany.

    PubMed

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E; Ellerbrock, Ruth; Bruelheide, Helge; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season.

  6. Calcium precipitate induced aerobic granulation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules.

  7. Peloids: a bacterially-induced origin

    SciTech Connect

    Chafetz, H.S.

    1985-01-01

    The origin of peloids within modern reef accumulations has been a controversial subject for almost 20 years. Freshly broken and slabbed splits of samples from Holocene-Pleistocene reef tracts from Jamaica, Belize and Florida, were observed with an SEM; the majority of the specimens had been etched in dilute HC1 prior to coating. Peloids commonly occur within borings in corals and other reef constituents. The peloids are spherical bodies, generally 20-60u in diameter, composed of high-magnesian calcite. They have a fine-grained center of anhedral grains and a dentate exterior of clear euhedral spar. In thin section, the centers commonly are light brown indicating the presence of organic matter. Spherical to elliptical bacterial clumps, approximately 15u in diameter, are evident in SEM views of etched samples from all three locales, whereas no bacteria were observed in non-etched samples. Their apparent absence in non-etched samples is because they occur encased in calcite. The reefal peloids are similar to bacterially-induced precipitates that occur in some travertine deposits. The similarities include: diameter (20-60u), structure, composition, and occurrence in a restricted or harsh environment (borings within corals or in hot H/sub 2/S-rich waters). Laboratory experiments have demonstrated that bacteria can induce carbonate precipitation. Therefore, it is my contention that peloids in modern reefs are bacterially-induced precipitated grains.

  8. Inducing Mineral Precipitation in Groundwater by Addition of Phosphate

    SciTech Connect

    Karen E. Wright; Yoshiko Fujita; Thomas Hartmann; Mark Conrad

    2011-10-01

    Induced precipitation of phosphate minerals to scavenge trace metals and radionuclides from groundwater is a potential remediation approach for contaminated aquifers. Phosphate minerals can sequester trace elements by primary mineral formation, solid solution formation and/or adsorption, and they are poorly soluble under many environmental conditions, making them attractive for long-term sustainable remediation. The success of such engineered schemes will depend on the particular mineral phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for induced phosphate mineral precipitation rely on the stimulation of native groundwater populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 ml-1) within the precipitation medium. We also tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM). The experiments showed that the general progression of mineral precipitation was similar under all of the conditions, with initial formation of amorphous calcium carbonate, and transformation to poorly crystalline hydroxyapatite (HAP) by the end of the week-long experiments. The presence of the bacterial cells appeared to delay precipitation, although by the end of 7 days the overall extent of precipitation was similar for all of the treatments. The stoichiometry of the final precipitates as well as results of Rietveld refinement of x-ray diffraction data indicated that the treatments including organic acids and bacterial cells resulted in increased distortion of the HAP crystal lattice, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the phosphate minerals was decreased in the treatments

  9. Inducing mineral precipitation in groundwater by addition of phosphate

    PubMed Central

    2011-01-01

    Background Induced precipitation of phosphate minerals to scavenge trace elements from groundwater is a potential remediation approach for contaminated aquifers. The success of engineered precipitation schemes depends on the particular phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for phosphate mineral precipitation rely on stimulation of native microbial populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 mL-1) added to the precipitation medium. In addition, we tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM). Results The general progression of mineral precipitation was similar under all of the study conditions, with initial formation of amorphous calcium phosphate, and transformation to poorly crystalline hydroxylapatite (HAP) within one week. The presence of the bacterial cells appeared to delay precipitation, although by the end of the experiments the overall extent of precipitation was similar for all treatments. The stoichiometry of the final precipitates as well as Rietveld structure refinement using x-ray diffraction data indicated that the presence of organic acids and bacterial cells resulted in an increasing a and decreasing c lattice parameter, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the solids was decreased in the treatments with cells and organic acids, compared to the control. Conclusions Our results suggest that the minerals formed initially during an engineered precipitation application for trace element sequestration may not be the ones that control long-term immobilization of the contaminants. In addition, the presence of

  10. Magnesium isotope fractionation in bacterial mediated carbonate precipitation experiments

    NASA Astrophysics Data System (ADS)

    Parkinson, I. J.; Pearce, C. R.; Polacskek, T.; Cockell, C.; Hammond, S. J.

    2012-12-01

    Magnesium is an essential component of life, with pivotal roles in the generation of cellular energy as well as in plant chlorophyll [1]. The bio-geochemical cycling of Mg is associated with mass dependant fractionation (MDF) of the three stable Mg isotopes [1]. The largest MDF of Mg isotopes has been recorded in carbonates, with foraminiferal tests having δ26Mg compositions up to 5 ‰ lighter than modern seawater [2]. Magnesium isotopes may also be fractionated during bacterially mediated carbonate precipitation and such carbonates are known to have formed in both modern and ancient Earth surface environments [3, 4], with cyanobacteria having a dominant role in carbonate formation during the Archean. In this study, we aim to better constrain the extent to which Mg isotope fractionation occurs during cellular processes, and to identify when, and how, this signal is transferred to carbonates. To this end we have undertaken biologically-mediated carbonate precipitation experiments that were performed in artificial seawater, but with the molar Mg/Ca ratio set to 0.6 and with the solution spiked with 0.4% yeast extract. The bacterial strain used was marine isolate Halomonas sp. (gram-negative). Experiments were run in the dark at 21 degree C for two to three months and produced carbonate spheres of various sizes up to 300 μm in diameter, but with the majority have diameters of ~100 μm. Control experiments run in sterile controls (`empty` medium without bacteria) yielded no precipitates, indicating a bacterial control on the precipitation. The carbonate spheres are produced are amenable to SEM, EMP and Mg isotopic analysis by MC-ICP-MS. Our new data will shed light on tracing bacterial signals in carbonates from the geological record. [1] Young & Galy (2004). Rev. Min. Geochem. 55, p197-230. [2] Pogge von Strandmann (2008). Geochem. Geophys. Geosys. 9 DOI:10.1029/2008GC002209. [3] Castanier, et al. (1999). Sed. Geol. 126, 9-23. [4] Cacchio, et al. (2003

  11. Responses of Soil Bacterial Communities to Nitrogen Deposition and Precipitation Increment Are Closely Linked with Aboveground Community Variation.

    PubMed

    Li, Hui; Xu, Zhuwen; Yang, Shan; Li, Xiaobin; Top, Eva M; Wang, Ruzhen; Zhang, Yuge; Cai, Jiangping; Yao, Fei; Han, Xingguo; Jiang, Yong

    2016-05-01

    It has been predicted that precipitation and atmospheric nitrogen (N) deposition will increase in northern China; yet, ecosystem responses to the interactive effects of water and N remain largely unknown. In particular, responses of belowground microbial community to projected global change and their potential linkages to aboveground macro-organisms are rarely studied. In this study, we examined the responses of soil bacterial diversity and community composition to increased precipitation and multi-level N deposition in a temperate steppe in Inner Mongolia, China, and explored the diversity linkages between aboveground and belowground communities. It was observed that N addition caused the significant decrease in bacterial alpha-diversity and dramatic changes in community composition. In addition, we documented strong correlations of alpha- and beta-diversity between plant and bacterial communities in response to N addition. It was found that N enriched the so-called copiotrophic bacteria, but reduced the oligotrophic groups, primarily by increasing the soil inorganic N content and carbon availability and decreasing soil pH. We still highlighted that increased precipitation tended to alleviate the effects of N on bacterial diversity and dampen the plant-microbe connections induced by N. The counteractive effects of N addition and increased precipitation imply that even though the ecosystem diversity and function are predicted to be negatively affected by N deposition in the coming decades; the combination with increased precipitation may partially offset this detrimental effect.

  12. Low-frequency electrical response to microbial induced sulfide precipitation

    NASA Astrophysics Data System (ADS)

    Ntarlagiannis, Dimitrios; Williams, Kenneth Hurst; Slater, Lee; Hubbard, Susan

    2005-12-01

    We investigated the sensitivity of low-frequency electrical measurements to microbe-induced metal sulfide precipitation. Three identical sand-packed monitoring columns were used; a geochemical column, an electrical column and a control column. In the first experiment, continuous upward flow of nutrients and metals in solution was established in each column. Cells of Desulfovibrio vulgaris (D. vulgaris) were injected into the center of the geochemical and electrical columns. Geochemical sampling and post-experiment destructive analysis showed that microbial induced sulfate reduction led to metal precipitation on bacteria cells, forming motile biominerals. Precipitation initially occurred in the injection zone, followed by chemotactic migration of D. vulgaris and ultimate accumulation around the nutrient source at the column base. Results from this experiment conducted with metals show (1) polarization anomalies, up to 14 mrad, develop at the bacteria injection and final accumulation areas, (2) the onset of polarization increase occurs concurrently with the onset of lactate consumption, (3) polarization profiles are similar to calculated profiles of the rate of lactate consumption, and (4) temporal changes in polarization and conduction correlate with a geometrical rearrangement of metal-coated bacterial cells. In a second experiment, the same biogeochemical conditions were established except that no metals were added to the flow solution. Polarization anomalies were absent when the experiment was replicated without metals in solution. We therefore attribute the polarization increase observed in the first experiment to a metal-fluid interfacial mechanism that develops as metal sulfides precipitate onto microbial cells and form biominerals. Temporal changes in polarization and conductivity reflect changes in (1) the amount of metal-fluid interfacial area, and (2) the amount of electronic conduction resulting from microbial growth, chemotactic movement and final

  13. Induced calcium carbonate precipitation using Bacillus species.

    PubMed

    Seifan, Mostafa; Samani, Ali Khajeh; Berenjian, Aydin

    2016-12-01

    Microbially induced calcium carbonate precipitation is an emerging process for the production of self-healing concrete. This study was aimed to investigate the effects and optimum conditions on calcium carbonate biosynthesis. Bacillus licheniformis, Bacillus sphaericus, yeast extract, urea, calcium chloride and aeration were found to be the most significant factors affecting the biomineralization of calcium carbonate. It was noticed that the morphology of microbial calcium carbonate was mainly affected by the genera of bacteria (cell surface properties), the viscosity of the media and the type of electron acceptors (Ca(2+)). The maximum calcium carbonate concentration of 33.78 g/L was achieved at the optimum conditions This value is the highest concentration reported in the literature.

  14. Ultrasound influence upon calcium carbonate precipitation on bacterial cellulose membranes.

    PubMed

    Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin; Jipa, Iuliana; Dobre, Tanase; Dobre, Loredana

    2012-07-01

    The effect of ultrasonic irradiation (40 kHz) on the calcium carbonate deposition on bacterial cellulose membranes was investigated using calcium chloride (CaCl(2)) and sodium carbonate (Na(2)CO(3)) as starting reactants. The composite materials containing bacterial cellulose-calcium carbonate were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and color measurements. The polymorphs of calcium carbonate that were deposited on bacterial cellulose membranes in the presence or in the absence of ultrasonic irradiation were calcite and vaterite. The morphology of the obtained crystals was influenced by the concentration of starting solutions and by the presence of ultrasonic irradiation. In the presence of ultrasonic irradiation the obtained crystals were bigger and in a larger variety of shapes than in the absence of ultrasounds: from cubes of calcite to spherical and flower-like vaterite particles. Bacterial cellulose could be a good matrix for obtaining different types of calcium carbonate crystals.

  15. Carbon isotope fractionation during calcium carbonate precipitation induced by ureolytic bacteria

    NASA Astrophysics Data System (ADS)

    Millo, Christian; Dupraz, S.; Ader, M.; Guyot, F.; Thaler, C.; Foy, E.; Ménez, B.

    2012-12-01

    Ureolytic bacteria have been proposed as model organisms to investigate the potential of subsurface microorganisms to enhance carbon capture and storage through solubility- and mineral-trapping of CO2 induced by bacterial ureolysis and carbonate formation. Ideally, CO2 incorporation into carbonates can be readily traced using carbon isotope measurements. However, the carbon isotope systematics of bacterial ureolysis and associated carbonate precipitation is still poorly known. We determined the carbon isotope fractionations expressed during ureolysis and carbonate precipitation induced by Sporosarcina pasteurii at 30 °C. Our results indicate that bacterial ureolysis proceeds as a Rayleigh distillation characterized by a 13C-enrichment factor equal to -12.5‰. As precipitation proceeds, the δ13C value of CaCO3, initially 1-2.1‰ lower than that of dissolved inorganic carbon (DIC), evolves progressively until it is 0.5‰ higher than that of the DIC, i.e. close to the value predicted for isotopic equilibrium. The minor isotope disequilibrium at the onset of precipitation and its rapid evolution towards isotopic equilibrium point to bacterial carbonates as reliable recorders of the carbon isotope composition of DIC. This corroborates the potential utility of 13C-tracing for the quantification of microbially-induced CO2 sequestration into solid carbonates and DIC.

  16. Urease activity in microbiologically-induced calcite precipitation.

    PubMed

    Bachmeier, Keri L; Williams, Amy E; Warmington, John R; Bang, Sookie S

    2002-02-14

    The role of microbial urease in calcite precipitation was studied utilizing a recombinant Escherichia coli HB101 containing a plasmid, pBU11, that encodes Bacillus pasteurii urease. The calcite precipitation by E. coli HB101 (pBU11) was significant although its precipitation level was not as high as that by B. pasteurii. Addition of low concentrations (5-100 microM) of nickel, the cofactor of urease, to the medium further enhanced calcite precipitation by E. coli (pBU11). Calcite precipitation induced by both B. pasteurii and E. coli (pBU11) was inhibited in the presence of a urease inhibitor, acetohydroxamic acid (AHA). These observations on the recombinant urease have confirmed that urease activity is essential for microbiologically-induced calcite precipitation. Partially purified B. pasteurii urease was immobilized in polyurethane (PU) foam to compare the efficacy of calcite precipitation between the free and immobilized enzymes. The immobilized urease showed higher K(m) and lower V(max) values, which were reflected by a slower overall calcite precipitation. However, scanning electron micrographs (SEM) identified that the calcite precipitation occurred throughout the matrices of polyurethane. Furthermore, PU-immobilized urease retained higher enzymatic activities at high temperatures and in the presence of a high concentration of pronase, indicating that immobilization protects the enzyme activity from environmental changes.

  17. Reducing hydraulic conductivity of porous media using CaCO₃ precipitation induced by Sporosarcina pasteurii.

    PubMed

    Eryürük, Kağan; Yang, Suyin; Suzuki, Daisuke; Sakaguchi, Iwao; Akatsuka, Tetsuji; Tsuchiya, Takayuki; Katayama, Arata

    2015-03-01

    The effect on hydraulic conductivity in porous media of CaCO3 precipitation induced by Sporosarcina pasteurii (ATCC 11859) was investigated using continuous-flow columns containing glass beads between 0.01 mm and 3 mm in diameter. Resting S. pasteurii cells and a precipitation solution composed of 0.5 M CaCl2 and 0.5 M urea were introduced into the columns, and it was shown that the subsequent formation of CaCO3 precipitation reduced hydraulic conductivity from between 8.38 × 10(-1) and 3.27 × 10(-4) cm/s to between 3.70 × 10(-1) and 3.07 × 10(-5) cm/s. The bacterial cells themselves did not decrease the hydraulic conductivity. The amount of precipitation was proportional with the bacterial number in the column. The specific CaCO3 precipitation rate of the resting cells was estimated as 4.0 ± 0.1 × 10(-3) μg CaCO3/cell. Larger amounts of CaCO3 precipitation were deposited in columns packed with small glass beads than in those packed with large glass beads, resulting in a greater reduction in the hydraulic conductivity of the columns containing small glass beads. Analysis using the Kozeny-Carman equation suggested that the effect of microbially induced CaCO3 precipitation on hydraulic conductivity was not due to the formation of individual CaCO3 crystals but instead that the precipitate aggregated with the glass beads, thus increasing their diameter and consequently decreasing the pore size in the column.

  18. Interaction of Uranium with Bacterial Cell Surfaces: Inferences from Phosphatase-Mediated Uranium Precipitation

    PubMed Central

    Kulkarni, Sayali; Misra, Chitra Seetharam; Gupta, Alka; Ballal, Anand

    2016-01-01

    ABSTRACT Deinococcus radiodurans and Escherichia coli expressing either PhoN, a periplasmic acid phosphatase, or PhoK, an extracellular alkaline phosphatase, were evaluated for uranium (U) bioprecipitation under two specific geochemical conditions (GCs): (i) a carbonate-deficient condition at near-neutral pH (GC1), and (ii) a carbonate-abundant condition at alkaline pH (GC2). Transmission electron microscopy revealed that recombinant cells expressing PhoN/PhoK formed cell-associated uranyl phosphate precipitate under GC1, whereas the same cells displayed extracellular precipitation under GC2. These results implied that the cell-bound or extracellular location of the precipitate was governed by the uranyl species prevalent at that particular GC, rather than the location of phosphatase. MINTEQ modeling predicted the formation of predominantly positively charged uranium hydroxide ions under GC1 and negatively charged uranyl carbonate-hydroxide complexes under GC2. Both microbes adsorbed 6- to 10-fold more U under GC1 than under GC2, suggesting that higher biosorption of U to the bacterial cell surface under GC1 may lead to cell-associated U precipitation. In contrast, at alkaline pH and in the presence of excess carbonate under GC2, poor biosorption of negatively charged uranyl carbonate complexes on the cell surface might have resulted in extracellular precipitation. The toxicity of U observed under GC1 being higher than that under GC2 could also be attributed to the preferential adsorption of U on cell surfaces under GC1. This work provides a vivid description of the interaction of U complexes with bacterial cells. The findings have implications for the toxicity of various U species and for developing biological aqueous effluent waste treatment strategies. IMPORTANCE The present study provides illustrative insights into the interaction of uranium (U) complexes with recombinant bacterial cells overexpressing phosphatases. This work demonstrates the effects of aqueous

  19. Microbially induced and microbially catalysed precipitation: two different carbonate factories

    NASA Astrophysics Data System (ADS)

    Meister, Patrick

    2016-04-01

    The landmark paper by Schlager (2003) has revealed three types of benthic carbonate production referred to as "carbonate factories", operative at different locations at different times in Earth history. The tropical or T-factory comprises the classical platforms and fringing reefs and is dominated by carbonate precipitation by autotrophic calcifying metazoans ("biotically controlled" precipitation). The cool or C-factory is also biotically controlled but via heterotrophic, calcifying metazoans in cold and deep waters at the continental margins. A further type is the mud-mound or M-factory, where carbonate precipitation is supported by microorganisms but not controlled by a specific enzymatic pathway ("biotically induced" precipitation). How exactly the microbes influence precipitation is still poorly understood. Based on recent experimental and field studies, the microbial influence on modern mud mound and microbialite growth includes two fundamentally different processes: (1) Metabolic activity of microbes may increase the saturation state with respect to a particular mineral phase, thereby indirectly driving the precipitation of the mineral phase: microbially induced precipitation. (2) In a situation, where a solution is already supersaturated but precipitation of the mineral is inhibited by a kinetic barrier, microbes may act as a catalyser, i.e. they lower the kinetic barrier: microbially catalysed precipitation. Such a catalytic effect can occur e.g. via secreted polymeric substances or specific chemical groups on the cell surface, at which the minerals nucleate or which facilitate mechanistically the bonding of new ions to the mineral surface. Based on these latest developments in microbialite formation, I propose to extend the scheme of benthic carbonate factories of Schlager et al. (2003) by introducing an additional branch distinguishing microbially induced from microbially catalysed precipitation. Although both mechanisms could be operative in a M

  20. Linked redox precipitation of sulfur and selenium under anaerobic conditions by sulfate-reducing bacterial biofilms.

    PubMed

    Hockin, Simon L; Gadd, Geoffrey M

    2003-12-01

    A biofilm-forming strain of sulfate-reducing bacteria (SRB), isolated from a naturally occurring mixed biofilm and identified by 16S rDNA analysis as a strain of Desulfomicrobium norvegicum, rapidly removed 200 micro M selenite from solution during growth on lactate and sulfate. Elemental selenium and elemental sulfur were precipitated outside SRB cells. Precipitation occurred by an abiotic reaction with bacterially generated sulfide. This appears to be a generalized ability among SRB, arising from dissimilatory sulfide biogenesis, and can take place under low redox conditions and in the dark. The reaction represents a new means for the deposition of elemental sulfur by SRB under such conditions. A combination of transmission electron microscopy, environmental scanning electron microscopy, and cryostage field emission scanning electron microscopy were used to reveal the hydrated nature of SRB biofilms and to investigate the location of deposited sulfur-selenium in relation to biofilm elements. When pregrown SRB biofilms were exposed to a selenite-containing medium, nanometer-sized selenium-sulfur granules were precipitated within the biofilm matrix. Selenite was therefore shown to pass through the biofilm matrix before reacting with bacterially generated sulfide. This constitutes an efficient method for the removal of toxic concentrations of selenite from solution. Implications for environmental cycling and the fate of sulfur and selenium are discussed, and a general model for the potential action of SRB in selenium transformations is presented.

  1. Bacterially induced bone destruction: mechanisms and misconceptions.

    PubMed Central

    Nair, S P; Meghji, S; Wilson, M; Reddi, K; White, P; Henderson, B

    1996-01-01

    Normal bone remodelling requires the coordinated regulation of the genesis and activity of osteoblast and osteoclast lineages. Any interference with these integrated cellular systems can result in dysregulation of remodelling with the consequent loss of bone matrix. Bacteria are important causes of bone pathology in common conditions such as periodontitis, dental cysts, bacterial arthritis, and osteomyelitis. It is now established that many of the bacteria implicated in bone diseases contain or produce molecules with potent effects on bone cells. Some of these molecules, such as components of the gram-positive cell walls (lipoteichoic acids), are weak stimulators of bone resorption in vitro, while others (PMT, cpn60) are as active as the most active mammalian osteolytic factors such as cytokines like IL-1 and TNF. The complexity of the integration of bone cell lineage development means that there are still question marks over the mechanism of action of many well-known bone-modulatory molecules such as parathyroid hormone. The key questions which must be asked of the now-recognized bacterial bone-modulatory molecules are as follows: (i) what cell population do they bind to, (ii) what is the nature of the receptor and postreceptor events, and (iii) is their action direct or dependent on the induction of secondary extracellular bone-modulating factors such as cytokines, eicosanoids, etc. In the case of LPS, this ubiquitous gram-negative polymer probably binds to osteoblasts or other cells in bone through the CD14 receptor and stimulates them to release cytokines and eicosanoids which then induce the recruitment and activation of osteoclasts. This explains the inhibitor effects of nonsteroidal and anticytokine agents on LPS-induced bone resorption. However, other bacterial factors such as the potent toxin PMT may act by blocking the normal maturation pathway of the osteoblast lineage, thus inducing dysregulation in the tightly regulated process of resorption and

  2. Ice nucleators, bacterial cells and Pseudomonas syringae in precipitation at Jungfraujoch

    NASA Astrophysics Data System (ADS)

    Stopelli, Emiliano; Conen, Franz; Guilbaud, Caroline; Zopfi, Jakob; Alewell, Christine; Morris, Cindy E.

    2017-03-01

    Ice nucleation is a means by which the deposition of an airborne microorganism can be accelerated under favourable meteorological conditions. Analysis of 56 snow samples collected at the high-altitude observatory Jungfraujoch (3580 m a.s.l.) revealed an order-of-magnitude-larger dynamic range of ice-nucleating particles active at -8 °C (INPs-8) compared to the total number of bacterial cells (of which on average 60 % was alive). This indicates a shorter atmospheric residence time for INPs-8. Furthermore, concentrations of INPs-8 decreased much faster, with an increasing fraction of water precipitated from the air mass prior to sampling, than the number of total bacterial cells. Nevertheless, at high wind speeds (> 50 km h-1) the ratio of INPs-8 to total bacterial cells largely remained in a range between 10-2 and 10-3, independent of prior precipitation, likely because of recent injections of particles in regions upwind. Based on our field observations, we conclude that ice nucleators travel shorter legs of distance with the atmospheric water cycle than the majority of bacterial cells. A prominent ice-nucleating bacterium, Pseudomonas syringae, has been previously supposed to benefit from this behaviour as a means to spread via the atmosphere and to colonise new host plants. Therefore, we targeted this bacterium with a selective cultivation approach. P. syringae was successfully isolated for the first time at such an altitude in 3 of 13 samples analysed. Colony-forming units of this species constituted a minor fraction (10-4) of the numbers of INPs-8 in these samples. Overall, our findings expand the geographic range of habitats where this bacterium has been found and corroborate theories on its robustness in the atmosphere and its propensity to spread to colonise new habitats.

  3. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  4. Construction of two ureolytic model organisms for the study of microbially induced calcium carbonate precipitation.

    PubMed

    Connolly, James; Kaufman, Megan; Rothman, Adam; Gupta, Rashmi; Redden, George; Schuster, Martin; Colwell, Frederick; Gerlach, Robin

    2013-09-01

    Two bacterial strains, Pseudomonas aeruginosa MJK1 and Escherichia coli MJK2, were constructed that both express green fluorescent protein (GFP) and carry out ureolysis. These two novel model organisms are useful for studying bacterial carbonate mineral precipitation processes and specifically ureolysis-driven microbially induced calcium carbonate precipitation (MICP). The strains were constructed by adding plasmid-borne urease genes (ureABC, ureD and ureFG) to the strains P. aeruginosa AH298 and E. coli AF504gfp, both of which already carried unstable GFP derivatives. The ureolytic activities of the two new strains were compared to the common, non-GFP expressing, model organism Sporosarcina pasteurii in planktonic culture under standard laboratory growth conditions. It was found that the engineered strains exhibited a lower ureolysis rate per cell but were able to grow faster and to a higher population density under the conditions of this study. Both engineered strains were successfully grown as biofilms in capillary flow cell reactors and ureolysis-induced calcium carbonate mineral precipitation was observed microscopically. The undisturbed spatiotemporal distribution of biomass and calcium carbonate minerals were successfully resolved in 3D using confocal laser scanning microscopy. Observations of this nature were not possible previously because no obligate urease producer that expresses GFP had been available. Future observations using these organisms will allow researchers to further improve engineered application of MICP as well as study natural mineralization processes in model systems.

  5. Rock fracture grouting with microbially induced carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Minto, James M.; MacLachlan, Erica; El Mountassir, Gráinne; Lunn, Rebecca J.

    2016-11-01

    Microbially induced carbonate precipitation has been proposed for soil stabilization, soil strengthening, and permeability reduction as an alternative to traditional cement and chemical grouts. In this paper, we evaluate the grouting of fine aperture rock fractures with calcium carbonate, precipitated through urea hydrolysis, by the bacteria Sporosarcina pasteurii. Calcium carbonate was precipitated within a small-scale and a near field-scale (3.1 m2) artificial fracture consisting of a rough rock lower surfaces and clear polycarbonate upper surfaces. The spatial distribution of the calcium carbonate precipitation was imaged using time-lapse photography and the influence on flow pathways revealed from tracer transport imaging. In the large-scale experiment, hydraulic aperture was reduced from 276 to 22 μm, corresponding to a transmissivity reduction of 1.71 × 10-5 to 8.75 × 10-9 m2/s, over a period of 12 days under constantly flowing conditions. With a modified injection strategy a similar three orders of magnitude reduction in transmissivity was achieved over a period of 3 days. Calcium carbonate precipitated over the entire artificial fracture with strong adhesion to both upper and lower surfaces and precipitation was controlled to prevent clogging of the injection well by manipulating the injection fluid velocity. These experiments demonstrate that microbially induced carbonate precipitation can successfully be used to grout a fracture under constantly flowing conditions and may be a viable alternative to cement based grouts when a high level of hydraulic sealing is required and chemical grouts when a more durable grout is required.

  6. Low-frequency Electrical Response to Microbial Induced Sulfide Precipitation

    SciTech Connect

    Ntarlagiannis, Dimitrios; Williams, Kenneth H.; Slater, Lee D.; Hubbard, Susan S.

    2005-11-19

    We investigated the sensitivity of low-frequency electrical measurements to microbeinduced metal sulfide precipitation. Three identical sand-packed monitoring columns were used; a geochemical column, an electrical column and a control column. In the first experiment, continuous upward flow of nutrients and metals in solution was established in each column. Cells of Desulfovibrio vulgaris (D. vulgaris) were injected into the center of the geochemical and electrical columns. Geochemical sampling and post-experiment destructive analysis showed that microbial induced sulfate reduction led to metal precipitation on bacteria cells, forming motile biominerals. Precipitation initially occurred in the injection zone, followed by chemotactic migration of D. vulgaris and ultimate accumulation around the nutrient source at the column base.

  7. Microbially Induced Calcite Precipitation for Subsurface Immobilization of Contaminants

    NASA Astrophysics Data System (ADS)

    Smith, R. W.; Fujita, Y.; Ginn, T. R.; Hubbard, S. S.; Dafflon, B.; Delwiche, M.; Gebrehiwet, T.; Henriksen, J. R.; Peterson, J.; Taylor, J. L.

    2011-12-01

    Subsurface radionuclide and metal contaminants throughout the U.S. Department of Energy (DOE) complex pose one of the greatest challenges for long-term stewardship. One promising stabilization mechanism for divalent trace ions, such as the short-lived radionuclide 90Sr, is co-precipitation in calcite. We have found that calcite precipitation and co-precipitation of Sr can be accelerated by the activity of urea hydrolyzing microorganisms, that higher calcite precipitation rates can result in increased Sr partitioning, and that nutrient additions can stimulate ureolytic activity. To extend our understanding of microbially induced calcite precipitation (MICP) in an aquifer setting a continuous recirculation field experiment evaluating MICP was conducted at the Integrated Field Research Challenge (IFRC) site located at Rifle, CO. In this experiment, groundwater extracted from an onsite well was amended with urea (total mass of 42.5 kg) and molasses (a carbon and electron donor) and re-injected into a well approximately 4 meters up-gradient for a period of 12 days followed by 10 months of groundwater sampling and monitoring. Crosshole radar and electrical tomographic data were collected prior, during, and after the MICP treatment. The urea and molasses treatment resulted in an enhanced population of sediment associated urea hydrolyzing organisms as evidenced by increases in the number of ureC gene copies, increases in 14C urea hydrolysis rates, and long-term observations of ammonium (a urea hydrolysis product) in the injection, extraction and down gradient monitoring wells. Permeability changes and increases in the calcite saturation indexes in the well field suggest that mineral precipitation has occurred; ongoing analysis of field samples seeks to confirm this. Changes in dielectric constant and electrical conductivity were used to interpret the spatiotemporal distribution of the injectate and subsequent calcite precipitation. Modeling activities are underway to

  8. [Induction of metamorphosis in planulae : I. The bacterial inducer].

    PubMed

    Müller, Werner A

    1973-06-01

    1. The metamorphosis of the planulae ofHydractinia echinata (Hydrozoa) is induced by certain marine, gramnegative bacteria which at the end of the exponential growth release a stimulating principle. 2. The stimulus is liberated by stationary cells previously cultivated at low population densities (up to 10(7) cells/ml) in a proper medium (e.g. extract of meat). Transfer into seawater lacking nutritive sources enhances the inductive capacity. 3. The concentration of the inducing agent normally surpasses the threshold level only in the close microenvironment of living cells. But when shocked by a drop in the osmotic pressure the bacteria discharge increased amounts which become traceable in the filtered cell-free medium. 4. Thus the inducer can be accumulated and isolated by a process of osmotic shock which does not affect the viability of the microbes. The principle belongs to a category of microbial substances which are subsumed under the comprehensive term "leakage"-products. 5. The active principle can be precipitated from the leakage solution with acetone and extracted with chloroform. The inducer seems to be an unstable, nondialyzable, polar lipid. 6. In order to evoke complete metamorphosis the isolated agent must be applied in a pulse-like fashion. Using the onset of metamorphosis as criterion for the velocity of reaction the dose-response curves display Michaelis-like saturation kinetics. At short pulses the percentages of induced metamorphoses yield a saturation curve as well. This indicates that an enzyme or carrier-system is involved in the larval response. 7. The inducing effect of the bacterial principle is antagonized by ouabain. Conversely, high doses of the isolated leakage material abolish the ouabain inhibition. The primary effect of the inducer, therefore, can be interpreted as stimulation of the active cation transport, especially of the Na(+)/K(+)-ATPase.

  9. Epigenetic Alterations Induced by Bacterial Lipopolysaccharides.

    PubMed

    Chiariotti, Lorenzo; Coretti, Lorena; Pero, Raffaela; Lembo, Francesca

    2016-01-01

    Lipopolysaccharide (LPS) is one of the principal bacterial products known to elicit inflammation. Cells of myeloid lineage such as monocytes and macrophages, but also epithelial cells give rise to an inflammatory response upon LPS stimulation. This phenomenon implies reprogramming of cell specific gene expression that can occur through different mechanisms including epigenetic modifications. Given their intrinsic nature, epigenetic modifications may be involved both in the acute response to LPS and in the establishment of a preconditioned genomic state (epigenomic memory) that may potentially influence the host response to further contacts with microorganisms. Information has accumulated during the last years aimed at elucidating the epigenetic mechanisms which underlie the cellular LPS response. These findings, summarized in this chapter, will hopefully be a good basis for a definition of the complete cascade of LPS-induced epigenetic events and their biological significance in different cell types.

  10. Fracture-aperture alteration induced by calcite precipitation

    NASA Astrophysics Data System (ADS)

    Jones, T.; Detwiler, R. L.

    2013-12-01

    Mineral precipitation significantly alters the transport properties of fractured rock. Chemical solubility gradients that favor precipitation induce mineral growth, which decreases the local aperture and alters preferential flow paths. Understanding the resulting development of spatial heterogeneities is necessary to predict the evolution of transport properties in the subsurface. We present experimental results that quantify the relationship between mineral precipitation and aperture alteration in a transparent analog fracture, 7.62cm x 7.62cm, with a uniform aperture of ~200 μm. Prior to flow experiments, a pump circulated a super-saturated calcite solution over the bottom glass, coating the glass surface with calcite. This method of seeding resulted in clusters of calcite crystals with large reactive surface area and provided micro-scale variability in the aperture field. A continuous flow syringe pump injected a reactive fluid into the fracture at 0.5 ml/min. The fluid was a mixture of sodium bicarbonate (NaHCO3, 0.02M) and calcium chloride (CaCl2 0.0004M) with a saturation index, Ω, of 8.51 with respect to calcite. A strobed LED panel backlit the fracture and a high-resolution CCD camera monitored changes in transmitted light intensity. Light transmission techniques provided a quantitative measurement of fracture aperture over the flow field. Results from these preliminary experiments showed growth near the inlet of the fracture, with decreasing precipitation rates in the flow direction. Over a period of two weeks, the fracture aperture decreased by 17% within the first 4mm of the inlet. Newly precipitated calcite bridged individual crystal clusters and smoothed the reacting surface. This observation is an interesting contradiction to the expectation of surface roughening induced by mineral growth. Additionally, the aperture decreased uniformly across the width of the fracture due to the initial aperture distribution. Future experiments of precipitation

  11. Spectral induced polarization signatures of abiotic FeS precipitation

    SciTech Connect

    Ntarlagiannis, D.; Doherty, R.; Williams, K. H.

    2010-01-15

    In recent years, geophysical methods have been shown to be sensitive to microbial induced mineralization processes. The spectral induced polarization (SIP) method appears to be very promising for monitoring mineralization and microbial processes. With this work, we study the links of mineralization and SIP signals, in the absence of microbial activity. We recorded the SIP response during abiotic FeS precipitation. We show that the SIP signals are diagnostic of FeS mineralization and can be differentiated from SIP signals from bio-mineralization processes. More specifically the imaginary conductivity shows almost linear dependence on the amount of FeS precipitating out of solution, above the threshold value 0.006 gr under our experimental conditions. This research has direct implications for the use of the SIP method as a monitoring, and decision making, tool for sustainable remediation of metals in contaminated soils and groundwater.

  12. Model for Strain-Induced Precipitation Kinetics in Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Medina, Sebastian F.; Quispe, Alberto; Gomez, Manuel

    2013-10-01

    Based on Dutta and Sellars's expression for the start of strain-induced precipitation in microalloyed steels, a new model has been constructed which takes into account the influence of variables such as microalloying element percentages, strain, temperature, strain rate, and grain size. Although the equation given by these authors reproduces the typical "C" shape of the precipitation start time (P s) curve well, the expression is not reliable for all cases. Recrystallization-precipitation-time-temperature diagrams have been plotted thanks to a new experimental study carried out by means of hot torsion tests on approximately twenty microalloyed steels with different Nb, V, and Ti contents. Mathematical analysis of the results recommends the modification of some parameters such as the supersaturation ratio (K s) and constant B, which is no longer a constant, but a function of K s when the latter is calculated at the nose temperature (T N) of the P s curve. The value of parameter B is deduced from the minimum point or nose of the P s curve, where ∂t 0.05/∂T is equal to zero, and it can be demonstrated that B cannot be a constant. The new expressions for these parameters are derived from the latest studies undertaken by the authors and this work represents an attempt to improve the model. The expressions are now more consistent and predict the precipitation-time-temperature curves with remarkable accuracy. The model for strain-induced precipitation kinetics is completed by means of Avrami's equation.

  13. Microbially Induced Carbonate Precipitation For Engineered Sealing Of Fractured Rock

    NASA Astrophysics Data System (ADS)

    Minto, J. M.; Lunn, R. J.; El Mountassir, G.

    2015-12-01

    ContextEngineering works in the subsurface often requires ground water ingress through fractures in the rock to be minimised. Traditionally cement based grouts have been used for this purpose, however chemical and alternative grouts are increasingly used. A promising alternative grout utilises bacteria to rapidly initiate the precipitation of calcium carbonate in a process termed microbially induced carbonate precipitation (MICP). Advantages of this process over conventional grouts are very low viscosity and small particle size allowing penetration into small aperture fractures, low toxicity and low associated carbon footprint. The use of MICP for soil stabilisation has been demonstrated and small scale fractures have been sealed in the lab, yet where the CaCO3 precipitates within large fractures is poorly understood. AimThe aim of this project was to assess the feasibility of MICP for large scale fracture sealing and to identify the optimum injection strategy that would allow controllable precipitation of CaCO3 over a large area and hence create a long-lasting reduction in fracture transmissivity. A 3m2 artificial fracture consisting of a rough-cut granite lower surface and transparent polycarbonate upper surface with a central injection well was created (Figure 1) and sealed twice with MICP: the first experiment to determine the transmissivity reduction achievable and the second experiment to optimise where CaCO3 precipitation occurred. The sealing process was then simulated in a model developed with CFD software OpenFOAM. ResultsThe transmissivity of the 300μm hydraulic aperture fracture was reduced from 1.7x10-5 to 8.8x10-9m2/s with 12 injections in the first experiment. A similar transmissivity reduction was achieved with only five injections in the second optimised experiment. Through the transparent upper fracture surface, CaCO3 precipitation was visible over the entire 3m2 fracture and attachment to both the top and bottom surfaces was very strong. This

  14. Biofilm-induced calcium carbonate precipitation: application in the subsurface

    NASA Astrophysics Data System (ADS)

    Phillips, A. J.; Eldring, J.; Lauchnor, E.; Hiebert, R.; Gerlach, R.; Mitchell, A. C.; Esposito, R.; Cunningham, A. B.; Spangler, L.

    2012-12-01

    We have investigated mitigation strategies for sealing high permeability regions, like fractures, in the subsurface. This technology has the potential to, for example, improve the long-term security of geologically-stored carbon dioxide (CO2) by sealing fractures in cap rocks or to mitigate leakage pathways to prevent contamination of overlying aquifers from hydraulic fracturing fluids. Sealing technologies using low-viscosity fluids are advantageous since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. In this technology, aqueous solutions and suspensions are used to promote microbially-induced mineral precipitation which can be applied in subsurface environments. To this end, a strategy was developed to twice seal a hydraulically fractured, 74 cm (2.4') diameter Boyles Sandstone core, collected in North-Central Alabama, with biofilm-induced calcium carbonate (CaCO3) precipitates under ambient pressures. Sporosarcina pasteurii biofilms were established and calcium and urea containing reagents were injected to promote saturation conditions favorable for CaCO3 precipitation followed by growth reagents to resuscitate the biofilm's ureolytic activity. Then, in order to evaluate this process at relevant deep subsurface pressures, a novel high pressure test vessel was developed to house the 74 cm diameter core under pressures as high as 96 bar (1,400 psi). After determining that no impact to the fracture permeability occurred due to increasing overburden pressure, the fractured core was sealed under subsurface relevant pressures relating to 457 meters (1,500 feet) below ground surface (44 bar (650 psi) overburden pressure). After fracture sealing under both ambient and subsurface relevant pressure conditions, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO3 mineralization. These studies suggest

  15. The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

    NASA Astrophysics Data System (ADS)

    Dunham-Cheatham, Sarrah; Rui, Xue; Bunker, Bruce; Menguy, Nicolas; Hellmann, Roland; Fein, Jeremy

    2011-05-01

    In this study, we test the potential for passive cell wall biomineralization by determining the effects of non-metabolizing bacteria on the precipitation of uranyl, lead, and calcium phosphates from a range of over-saturated conditions. Experiments were performed using Gram-positive Bacillus subtilis and Gram-negative Shewanella oneidensis MR-1. After equilibration, the aqueous phases were sampled and the remaining metal and P concentrations were analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES); the solid phases were collected and analyzed using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS). At the lower degrees of over-saturation studied, bacterial cells exerted no discernable effect on the mode of precipitation of the metal phosphates, with homogeneous precipitation occurring exclusively. However, at higher saturation states in the U system, we observed heterogeneous mineralization and extensive nucleation of hydrogen uranyl phosphate (HUP) mineralization throughout the fabric of the bacterial cell walls. This mineral nucleation effect was observed in both B. subtilis and S. oneidensis cells. In both cases, the biogenic mineral precipitates formed under the higher saturation state conditions were significantly smaller than those that formed in the abiotic controls. The cell wall nucleation effects that occurred in some of the U systems were not observed under any of the saturation state conditions studied in the Pb or Ca systems. The presence of B. subtilis significantly decreased the extent of precipitation in the U system, but had little effect in the Pb and Ca systems. At least part of this effect is due to higher solubility of the nanoscale HUP precipitate relative to macroscopic HUP. This study documents several effects of non-metabolizing bacterial cells on the nature and extent of metal phosphate precipitation. Each of these effects likely contributes to higher

  16. Urine Bacterial Community Convergence through Fertilizer Production: Storage, Pasteurization, and Struvite Precipitation.

    PubMed

    Lahr, Rebecca H; Goetsch, Heather E; Haig, Sarah J; Noe-Hays, Abraham; Love, Nancy G; Aga, Diana S; Bott, Charles B; Foxman, Betsy; Jimenez, Jose; Luo, Ting; Nace, Kim; Ramadugu, Kirtana; Wigginton, Krista R

    2016-11-01

    Source-separated human urine was collected from six public events to study the impact of urine processing and storage on bacterial community composition and viability. Illumina 16S rRNA gene sequencing revealed a complex community of bacteria in fresh urine that differed across collection events. Despite the harsh chemical conditions of stored urine (pH > 9 and total ammonia nitrogen > 4000 mg N/L), bacteria consistently grew to 5 ± 2 × 10(8) cells/mL. Storing hydrolyzed urine for any amount of time significantly reduced the number of operational taxonomic units (OTUs) to 130 ± 70, increased Pielou evenness to 0.60 ± 0.06, and produced communities dominated by Clostridiales and Lactobacillales. After 80 days of storage, all six urine samples from different starting materials converged to these characteristics. Urine pasteurization or struvite precipitation did not change the microbial community, even when pasteurized urine was stored for an additional 70 days. Pasteurization decreased metabolic activity by 50 ± 10% and additional storage after pasteurization did not lead to recovery of metabolic activity. Urine-derived fertilizers consistently contained 16S rRNA genes belonging to Tissierella, Erysipelothrix, Atopostipes, Bacteroides, and many Clostridiales OTUs; additional experiments must determine whether pathogenic species are present, responsible for observed metabolic activity, or regrow when applied.

  17. Influence of calcium sources on microbially induced calcium carbonate precipitation by Bacillus sp. CR2.

    PubMed

    Achal, Varenyam; Pan, Xiangliang

    2014-05-01

    Stimulation of microbially induced calcium carbonate precipitation (MICCP) is likely to be influenced by calcium sources. In order to study such influences, we performed MICCP using Bacillus sp. CR2 in nutrient broth containing urea, supplemented with different calcium sources (calcium chloride, calcium oxide, calcium acetate and calcium nitrate). The experiment lasted 7 days, during which bacterial growth, urease activity, calcite production and pH were measured. Our results showed that calcium chloride is the better calcium source for MICCP process, since it provides higher urease activity and more calcite production. The influences of calcium sources on MICCP were further studied using Fourier transform-infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. These analyses confirmed that the precipitate formed was CaCO3 and composed of predominantly calcite crystals with a little amount of aragonite and vaterite crystals. The maximum yield of calcite precipitation was achievable with calcium chloride followed by calcium nitrate as a calcium source. The results of present study may be applicable to media preparation during efficient MICCP process.

  18. Autophagy Induced by Calcium Phosphate Precipitates Targets Damaged Endosomes*

    PubMed Central

    Chen, Xi; Khambu, Bilon; Zhang, Hao; Gao, Wentao; Li, Min; Chen, Xiaoyun; Yoshimori, Tamotsu; Yin, Xiao-Ming

    2014-01-01

    Calcium phosphate precipitates (CPPs) form complexes with DNA, which enter cells via endocytosis. Under this condition CPPs induce autophagy via the canonic autophagy machinery. Here we showed that CPP-induced autophagy was also dependent on endocytosis as the process was significantly inhibited by methyl-β-cyclodextrin and dynasore, which suppress clathrin-dependent endocytosis. Consistently, CPP treatment triggered the formation of filipin-positive intracellular vesicles whose membranes are rich in cholesterol. Unexpectedly, these vesicles were also positive for galectin 3, suggesting that they were damaged and the membrane glycans became accessible to galectins to bind. Endosome damage was caused by endocytosis of CPPs and was reversed by calcium chelators or by endocytosis inhibitors. Notably, CPP-induced LC3-positive autophagosomes were colocalized with galectin 3, ubiquitin, and p62/SQSTM1. Inhibition of galectin 3 reduced p62 puncta and autophagosome formation. Knockdown of p62 additionally inhibited the colocalization of autophagosomes with galectins. Furthermore, most of the galectin 3-positive vesicles were colocalized with Rab7 or LAMP1. Agents that affect endosome/lysosome maturation and function, such as bafilomycin A1, also significantly affected CPP-induced tubulovesicular autophagosome formation. These findings thus indicate that endocytosed CPPs caused endosome damage and recruitment of galectins, particularly at the later endosome stage, which led to the interaction of the autophagosomal membranes with the damaged endosome in the presence of p62. PMID:24619419

  19. Photo-Induced Effect on Bacterial Cells

    NASA Astrophysics Data System (ADS)

    El Batanouny, M. H.; Amin, Rehab M.; Naga, M. I.; Ibrahim, M. K.

    2010-04-01

    Bacterial resistance against antibiotics is an increasing problem in medicine. This stimulates study of other bactericidal regimens, one of which is photodynamic therapy (PDT), which involves the killing of bacterial species by low power laser light (LLL) in the presence of photosensitizing agent. It has already been shown that, various gram- negative and gram-positive bacteria can be killed by photodynamic therapy in vitro, using exogenous sensitizers. The mechanisms of laser action on bacteria are not adequately understood. Here, PDT on H. pylori, as an example of gram negative bacteria was studied. The ultra structure changes of the organism after PDT were examined under electron microscope. Neither Irradiation with laser without sensitizer nor sensitizing without laser has any lethal effect on bacterial cells. However, the successful lethal photosensitization was achieved by applying certain laser dose with the corresponding concentration of the photosensitizer. On the other hand, PDT has no significant effect on the genomic DNA of the cells.

  20. Torque-induced precession of bacterial flagella

    NASA Astrophysics Data System (ADS)

    Shimogonya, Yuji; Sawano, Yoichiro; Wakebe, Hiromichi; Inoue, Yuichi; Ishijima, Akihiko; Ishikawa, Takuji

    2015-12-01

    The bacterial flagellar motor is an ion-driven rotary machine in the cell envelope of bacteria. Using a gold nanoparticle as a probe, we observed the precession of flagella during rotation. Since the mechanism of flagella precession was unknown, we investigated it using a combination of full simulations, theory, and experiments. The results show that the mechanism can be well explained by fluid mechanics. The validity of our theory was confirmed by our full simulation, which was utilized to predict both the filament tilt angle and motor torque from experimental flagellar precession data. The knowledge obtained is important in understanding mechanical properties of the bacterial motor and hook.

  1. Torque-induced precession of bacterial flagella.

    PubMed

    Shimogonya, Yuji; Sawano, Yoichiro; Wakebe, Hiromichi; Inoue, Yuichi; Ishijima, Akihiko; Ishikawa, Takuji

    2015-12-22

    The bacterial flagellar motor is an ion-driven rotary machine in the cell envelope of bacteria. Using a gold nanoparticle as a probe, we observed the precession of flagella during rotation. Since the mechanism of flagella precession was unknown, we investigated it using a combination of full simulations, theory, and experiments. The results show that the mechanism can be well explained by fluid mechanics. The validity of our theory was confirmed by our full simulation, which was utilized to predict both the filament tilt angle and motor torque from experimental flagellar precession data. The knowledge obtained is important in understanding mechanical properties of the bacterial motor and hook.

  2. CO2 sequestration by ureolytic microbial consortia through microbially-induced calcite precipitation.

    PubMed

    Okyay, Tugba O; Nguyen, Hang N; Castro, Sarah L; Rodrigues, Debora F

    2016-12-01

    Urea is an abundant nitrogen-containing compound found in urine of mammals and widely used in fertilizers. This compound is part of the nitrogen biogeochemical cycle and is easily biodegraded by ureolytic microorganisms that have the urease enzyme. Previous studies, with ureolytic isolates, have shown that some ureolytic microorganisms are able to sequester CO2 through a process called microbially-induced calcium carbonate precipitation. The present study investigates 15 ureolytic consortia obtained from the "Pamukkale travertines" and the "Cave Without A Name" using different growth media to identify the possible bacterial genera responsible for CO2 sequestration through the microbially-induced calcite precipitation (MICP). The community structure and diversity were determined by deep-sequencing. The results showed that all consortia presented varying CO2 sequestration capabilities and MICP rates. The CO2 sequestration varied between 0 and 86.4%, and it depended largely on the community structure, as well as on pH. Consortia with predominance of Comamonas, Plesiomonas and Oxalobacter presented reduced CO2 sequestration. On the other hand, consortia dominated by Sporosarcina, Sphingobacterium, Stenotrophomonas, Acinetobacter, and Elizabethkingia showed higher rates of CO2 uptake in the serum bottle headspace.

  3. Minor changes in soil bacterial and fungal community composition occur in response to monsoon precipitation in a semiarid grassland.

    PubMed

    McHugh, Theresa A; Koch, George W; Schwartz, Egbert

    2014-08-01

    Arizona and New Mexico receive half of their annual precipitation during the summer monsoon season, making this large-scale rain event critical for ecosystem productivity. We used the monsoon rains to explore the responses of soil bacterial and fungal communities to natural moisture pulses in a semiarid grassland. Through 454 pyrosequencing of the 16S rRNA gene and ITS region, we phylogenetically characterized these communities at 22 time points during a summer season. Relative humidity increased before the rains arrived, creating conditions in soil that allowed for the growth of microorganisms. During the course of the study, the relative abundances of most bacterial phyla showed little variation, though some bacterial populations responded immediately to an increase in soil moisture once the monsoon rains arrived. The Firmicutes phylum experienced over a sixfold increase in relative abundance with increasing water availability. Conversely, Actinobacteria, the dominant taxa at our site, were negatively affected by the increase in water availability. No relationship was found between bacterial diversity and soil water potential. Bacterial community structure was unrelated to all environmental variables that we measured, with the exception of a significant relationship with atmospheric relative humidity. Relative abundances of fungal phyla fluctuated more throughout the season than bacterial abundances did. Variation in fungal community structure was unrelated to soil water potential and to most environmental variables. However, ordination analysis showed a distinct fungal community structure late in the season, probably due to plant senescence.

  4. North west cape-induced electron precipitation and theoretical simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen-xia; Li, Xin-qiao; Wang, Chen-Yu; Chen, Lun-Jin

    2016-11-01

    Enhancement of the electron fluxes in the inner radiation belt, which is induced by the powerful North West Cape (NWC) very-low-frequency (VLF) transmitter, have been observed and analyzed by several research groups. However, all of the previous publications have focused on NWC-induced > 100-keV electrons only, based on observations from the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) and the Geostationary Operational Environmental Satellite (GOES) satellites. Here, we present flux enhancements with 30-100-keV electrons related to NWC transmitter for the first time, which were observed by the GOES satellite at night. Similar to the 100-300-keV precipitated-electron behavior, the low energy 30-100-keV electron precipitation is primarily located east of the transmitter. However, the latter does not drift eastward to the same extent as the former, possibly because of the lower electron velocity. The 30-100-keV electrons are distributed in the L = 1.8-2.1 L-shell range, in contrast to the 100-300-keV electrons which are at L = 1.67-1.9. This is consistent with the perspective that the energy of the VLF-wave-induced electron flux enhancement decreases with higher L-shell values. We expand upon the rationality of the simultaneous enhancement of the 30-100- and 100-300-keV electron fluxes through comparison with the cyclotron resonance theory for the quasi-linear wave-particle interaction. In addition, we interpret the asymmetry characteristics of NWC electric power distribution in north and south hemisphere by ray tracing model. Finally, we present considerable discussion and show that good agreement exists between the observation of satellites and theory. Supported by the China Seismo-Electromagnetic Satellite Mission Ground-Based Verification Project of the Administration of Science, Technology, and Industry for National Defense and Asia-Pacific Space Cooperation Organization Project (APSCO-SP/PM-EARTHQUAKE).

  5. Characterization of Strain-Induced Precipitation in Inconel 718 Superalloy

    NASA Astrophysics Data System (ADS)

    Calvo, Jessica; Penalva, Mariluz; Cabrera, José María

    2016-08-01

    Inconel 718 presents excellent mechanical properties at high temperatures, as well as good corrosion resistance and weldability. These properties, oriented to satisfy the design requirements of gas turbine components, depend on microstructural features such as grain size and precipitation. In this work, precipitation-temperature-time diagrams have been derived based on a stress relaxation technique and the characterization of precipitates by scanning electron microscopy. By using this methodology, the effect of strain accumulation during processing on the precipitation kinetics can be determined. The results show that the characteristics of precipitation are significantly modified when plastic deformation is applied, and the kinetics are slightly affected by the amount of total plastic deformation.

  6. Effect of Mg/Ca ratios on microbially induced carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Balci, Nurgul; Demirel, Cansu; Seref Sonmez, M.; Kurt, M. Ali

    2016-04-01

    Influence of Mg/Ca ratios on microbially induced carbonate mineralogy were investigated by series of experiments carried out under various environmental conditions (Mg/Ca ratio, temperature and salinity). Halophilic bacterial cultures used for biomineralization experiments were isolated from hypersaline Lake Acıgöl (Denizli, SW Turkey), displaying extreme water chemistry with an average pH around 8.6 (Balci eta l.,2015). Enriched bacterial culture used in the experiments consisted of Halomonas saccharevitans strain AJ275, Halomonas alimentaria strain L7B; Idiomarina sp. TBZ29, 98% Idiomarina seosensis strain CL-SP19. Biomineralization experiments were set up using above enriched culture with Mg/Ca ratios of 0.05, 1, 4 and 15 and salinity of 8% and 15% experiments at 30oC and 10oC. Additionally, long-term biomineralization experiments were set up to last for a year, for Mg/Ca=4 and Mg/Ca=15 experiments at 30oC. For each experimental condition abiotic experiments were also conducted. Solution chemistry throughout incubation was monitored for Na, K, Mg, Ca, bicarbonate, carbonate, ammonium and phosphate for a month. At the end of the experiments, precipitates were collected and morphology and mineralogy of the biominerals were investigated and results were evaluated using the software DIFFRAC.SUITE EVA. Overall the preliminary results showed chemical precipitation of calcite, halite, hydromagnesite and sylvite. Results obtained from biological experiments indicate that, low Mg/Ca ratios (0.05 and 1) favor chlorapatite precipitation, whereas higher Mg/Ca ratios favor struvite precipitation. Biomineralization of dolomite, huntite and magnesite is favorable at high Mg/Ca ratios (4 and 15), in the presence of halophilic bacteria. Moreover, results indicate that supersaturation with respect to Mg (Mg/Ca=15) combined with NaCl (15%) inhibits biomineralization and forms chemical precipitates. 15% salinity is shown to favor chemical precipitation of mineral phases more than

  7. Accelerated microbial-induced CaCO3 precipitation in a defined coculture of ureolytic and non-ureolytic bacteria

    NASA Astrophysics Data System (ADS)

    Gat, D.; Tsesarsky, M.; Shamir, D.; Ronen, Z.

    2014-05-01

    Microbial-induced CaCO3 precipitation (MICP) is an innovative technique that harnesses bacterial activity for the modification of the physical properties of soils. Since stimulation of MICP by urea hydrolysis in natural soils is likely to be affected by interactions between ureolytic and non-ureolytic bacteria, we designed an experiment to examine the interactions between ureolytic and non-ureolytic bacteria and the effect of these interactions on MICP. An artificial groundwater-based rich medium was inoculated with two model species of bacteria, the ureolytic species Sporosarcina pasteurii and the non-ureolytic species Bacillus subtilis. The control treatment was inoculated with a pure culture of S. pasteurii. The following parameters were monitored during the course of the experiment: optical density, pH, the evolution of ammonium, dissolved calcium and dissolved inorganic carbon. The results showed that dissolved calcium was precipitated as CaCO3 faster in the mixed culture than in the control, despite less favorable chemical conditions in the mixed culture, i.e., lower pH and lower CO32- concentration. B. subtilis exhibited a considerably higher growth rate than S. pasteurii, resulting in higher density of bacterial cells in the mixed culture. We suggest that the presence of the non-ureolytic bacterial species, B. subtilis, accelerated the MICP process, via the supply of nucleation sites in the form of non-ureolytic bacterial cells.

  8. Bacterial sulfate reduction is the driving force for dolomite precipitation: New insights from CAS contents and δ34SCAS signatures of sedimentary dolomites

    NASA Astrophysics Data System (ADS)

    Baldermann, Andre; Mavromatis, Vasileios; Strauss, Harald; Dietzel, Martin

    2016-04-01

    Recent advances in the understanding of the underlying reaction pathways and environmental controls inducing the precipitation of dolomite in mostly marine and early diagenetic sedimentary environments suggest that bacterial activity and bacterial sulfate reduction are key processes during the dolomitization of magnesian CaCO3 precursors at ambient temperatures [1]. However, in evaporitic and marine-anoxic, organic-rich sediments the precipitating dolomite is usually non-stoichiometric, highly disordered and metastable and is thus often referred to as (proto)dolomite. Subsequent multiple recrystallization of the (proto)dolomite during burial diagenesis is currently suggested to result in a more stable (stoichiometric and ordered) type of dolomite. On the basis of (micro)textural and (isotope)geochemical signatures of pure dolostone and partly dolomitized platform carbonates exposed in the Upper Jurassic rock succession at Oker (Northern German Basin), we highlight here the important role of bacterial sulfate reduction on the formation of sedimentary dolomite. Our results indicate that the Oker dolomite has been formed by the early diagenetic replacement of pre-existing magnesian calcite and aragonite precursors through reaction with pristine-marine to slightly evaporitic and reducing seawater at temperatures between 26 °C and 37 °C. The elevated δ34SCAS values, from +17.9 to +19.7 ‰ (V-CDT), of the Oker dolomite, relative to the ambient Upper Jurassic seawater, indicate that bacterial sulfate reduction was active during dolomite precipitation. Moreover, the linear anti-correlation (R² = 0.98) between decreasing CAS content (~1000-2000 ppm) in dolomite and increasing degree of cation order (~0.35 to 0.50) of the dolomite lattice structure suggests that, besides temperature and diagenetically driven recrystallization events, incorporation of CAS during co-precipitation of dolomite significantly affects the composition, structure and stability of modern and

  9. Biotic and abiotic effects on CO2 sequestration during microbially-induced calcium carbonate precipitation.

    PubMed

    Okyay, Tugba Onal; Rodrigues, Debora F

    2015-03-01

    In this study, CO2 sequestration was investigated through the microbially-induced calcium carbonate precipitation (MICP) process with isolates obtained from a cave called 'Cave Without A Name' (Boerne, TX, USA) and the Pamukkale travertines (Denizli, Turkey). The majority of the bacterial isolates obtained from these habitats belonged to the genera Sporosarcina, Brevundimonas, Sphingobacterium and Acinetobacter. The isolates were investigated for their capability to precipitate calcium carbonate and sequester CO2. Biotic and abiotic effects of CO2 sequestration during MICP were also investigated. In the biotic effect, we observed that the rate and concentration of CO2 sequestered was dependent on the species or strains. The main abiotic factors affecting CO2 sequestration during MICP were the pH and medium components. The increase in pH led to enhanced CO2 sequestration by the growth medium. The growth medium components, on the other hand, were shown to affect both the urease activity and CO2 sequestration. Through the Plackett-Burman experimental design, the most important growth medium component involved in CO2 sequestration was determined to be urea. The optimized medium composition by the Plackett-Burman design for each isolate led to a statistically significant increase, of up to 148.9%, in CO2 uptake through calcification mechanisms.

  10. Role of peach proteins in juice precipitation induced by high pressure CO2.

    PubMed

    Zhao, Feng; Zhou, Linyan; Wang, Yongtao; Liao, Xiaojun

    2016-10-15

    To better understand the role of peach proteins in juice precipitation induced by high pressure CO2 (HPCD), proteins extracted from peach juice were subjected to HPCD and heat, and changes in particle size distribution (PSD) and structure were investigated. PSD analysis showed aggregations of proteins were both induced by HPCD and heat, but HPCD induced a stronger aggregation. The endotherm of HPCD- and heat-treated proteins moved to lower temperature, indicating that higher-order structures were altered after treatments. Furthermore, proteins related to HPCD- and heat-induced precipitation were analyzed by proteomics and bioinformatics. It was found that proteins with low content of α-helix and hydrogen bonds were more inclined to precipitate under HPCD, and HPCD precipitated proteins with more compact structures than heat, which might cause the stronger aggregation of proteins by HPCD. In conclusion, HPCD could induce the aggregation of peach proteins by destroying higher-order structures, which contributes to juice precipitation.

  11. Flow Induced by Bacterial Carpets and Transport of Microscale Loads

    NASA Astrophysics Data System (ADS)

    Buchmann, Amy; Fauci, Lisa; Leiderman, Karin; Strawbridge, Eva; Zhao, Longhua

    2015-11-01

    Microfluidic devices carry very small volumes of liquid though channels and may be used to gain insight into many biological applications including drug delivery and development. In many microfluidic experiments, it would be useful to mix the fluid within the chamber. However, the traditional methods of mixing and pumping at large length scales don't work at small length scales. Experimental work has suggested that the flagella of bacteria may be used as motors in microfluidic devices by creating a bacterial carpet. Mathematical modeling can be used to investigate this idea and to quantify flow induced by bacterial carpets. We simulate flow induced by bacterial carpets using the method of regularized Stokeslets, and also examine the transport of vesicles of finite size by arrays of rotating flagella.

  12. Colloidal precipitates related to Acid Mine Drainage: bacterial diversity and micro fungi-heavy metal interactions

    NASA Astrophysics Data System (ADS)

    Lucchetti, G.; Carbone, C.; Consani, S.; Zotti, M.; Di Piazza, S.; Pozzolini, M.; Giovine, M.

    2015-12-01

    In Acid Mine Drainage (AMD) settings colloidal precipitates control the mobility of Potential Toxic Elements (PTEs). Mineral-contaminant relationships (i.e. adsorption, ion-exchange, desorption) are rarely pure abiotic processes. Microbes, mainly bacteria and microfungi, can catalyze several reactions modifying the element speciation, as well as the bioavailability of inorganic pollutants. Soil, sediments, and waters heavily polluted with PTEs through AMD processes are a potential reservoir of extremophile bacteria and fungi exploitable for biotechnological purposes. Two different AMD related colloids, an ochraceous precipitate (deposited in weakly acidic conditions, composed by nanocrystalline goethite) and a greenish-blue precipitate (deposited at near-neutral pH, composed by allophane + woodwardite) were sampled. The aims of this work were to a) characterize the mycobiota present in these colloidal minerals by evaluating the presence of alive fungal propagules and extracting bacteria DNA; b) verify the fungal strains tolerance, and bioaccumulation capability on greenish-blue and ZnSO4 enriched media; c) evaluate potential impact of bacteria in the system geochemistry. The preliminary results show an interesting and selected mycobiota able to survive under unfavourable environmental conditions. A significant number of fungal strains were isolated in pure culture. Among them, species belonging to Penicillium and Trichoderma genera were tested on both greenish-blue and ZnSO4 enriched media. The results show a significant tolerance and bioaccumulation capability to some PTEs. The same colloidal precipitates were processed to extract bacteria DNA by using a specific procedure developed for sediments. The results give a good yield of nucleic acids and a positive PCR amplification of 16S rDNA accomplished the first step for future metagenomic analyses.

  13. Microbially-induced Carbonate Precipitation for Immobilization of Toxic Metals.

    PubMed

    Kumari, Deepika; Qian, Xin-Yi; Pan, Xiangliang; Achal, Varenyam; Li, Qianwei; Gadd, Geoffrey Michael

    2016-01-01

    Rapid urbanization and industrialization resulting from growing populations contribute to environmental pollution by toxic metals and radionuclides which pose a threat to the environment and to human health. To combat this threat, it is important to develop remediation technologies based on natural processes that are sustainable. In recent years, a biomineralization process involving ureolytic microorganisms that leads to calcium carbonate precipitation has been found to be effective in immobilizing toxic metal pollutants. The advantage of using ureolytic organisms for bioremediating metal pollution in soil is their ability to immobilize toxic metals efficiently by precipitation or coprecipitation, independent of metal valence state and toxicity and the redox potential. This review summarizes current understanding of the ability of ureolytic microorganisms for carbonate biomineralization and applications of this process for toxic metal bioremediation. Microbial metal carbonate precipitation may also be relevant to detoxification of contaminated process streams and effluents as well as the production of novel carbonate biominerals and biorecovery of metals and radionuclides that form insoluble carbonates.

  14. Electrolyte-induced precipitation of graphene oxide in its aqueous solution.

    PubMed

    Wang, Hui; Hu, Yun Hang

    2013-02-01

    Graphene oxide (GO) can easily dissolve in water to form a stable homogeneous solution due to its hydrophilic property and ionization of functional groups. However, in this paper, it is reported that a strong electrolyte (HCl, LiOH, LiCl, LiBr, KCl, or KBr) can destabilize the GO solution, causing GO precipitation. This indicates that the electrostatic repulsion plays a critical role in stabilizing aqueous GO solution. The electrolyte-induced precipitates were characterized by transmission electron microscopy (TEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The oxygen-containing functional groups of GO sheets, which are carboxyl, epoxy, and hydroxyl groups, remained unchanged during acid (HCl)- and salt (LiCl)-induced precipitations. In contrast, during the GO precipitation induced by a base (LiOH), the carboxyl group of GO sheets disappeared with a remarkable increase in hydroxyl group and aromatic C=C bonds. This indicates that the LiOH-induced GO precipitation resulted in the partial reduction of GO sheets. Furthermore, it was demonstrated that the HCl-induced GO precipitation is a feasible approach to deposit GO on a substrate as a Pt-free counter electrode for a dye-sensitized solar cell (DSSC), which exhibited 1.65% power conversion efficiency.

  15. Mycobacterium massiliense Induces Macrophage Extracellular Traps with Facilitating Bacterial Growth

    PubMed Central

    Yoon, Yina; Na, Yirang; Kim, Bum-Joon; Seok, Seung Hyeok

    2016-01-01

    Human neutrophils have been known to release neutrophil extracellular traps (NETs), antimicrobial DNA structures capable of capturing and killing microbes. Recently, a similar phenomenon has been reported in macrophages infected with various pathogens. However, a role for macrophages extracellular traps (METs) in host defense responses against Mycobacterium massiliense (M. mass) has yet to be described. In this study, we show that M. mass, a rapid growing mycobacterium (RGM), also induces the release of METs from PMA-differentiated THP-1 cells. Intriguingly, this process is not dependent on NADPH oxidase activity, which regulates NET formation. Instead, M. mass-induced MET formation partially depends on calcium influx and requires phagocytosis of high bacterial load. The METs consist of a DNA backbone embedded with microbicidal proteins such as histone, MPO and elastase. Released METs entrap M. mass and prevent their dissemination, but do not have bactericidal activity. Instead, they result in enhanced bacterial growth. In this regard, METs were considered to provide interaction of M. mass with cells and an environment for bacterial aggregation, which may facilitate mycobacterial survival and growth. In conclusion, our results demonstrate METs as an innate defense response against M. mass infection, and suggest that extracellular traps play a multifaceted role in the interplay between host and bacteria. PMID:27191593

  16. Divergent global precipitation changes induced by natural versus anthropogenic forcing.

    PubMed

    Liu, Jian; Wang, Bin; Cane, Mark A; Yim, So-Young; Lee, June-Yi

    2013-01-31

    As a result of global warming, precipitation is likely to increase in high latitudes and the tropics and to decrease in already dry subtropical regions. The absolute magnitude and regional details of such changes, however, remain intensely debated. As is well known from El Niño studies, sea-surface-temperature gradients across the tropical Pacific Ocean can strongly influence global rainfall. Palaeoproxy evidence indicates that the difference between the warm west Pacific and the colder east Pacific increased in past periods when the Earth warmed as a result of increased solar radiation. In contrast, in most model projections of future greenhouse warming this gradient weakens. It has not been clear how to reconcile these two findings. Here we show in climate model simulations that the tropical Pacific sea-surface-temperature gradient increases when the warming is due to increased solar radiation and decreases when it is due to increased greenhouse-gas forcing. For the same global surface temperature increase the latter pattern produces less rainfall, notably over tropical land, which explains why in the model the late twentieth century is warmer than in the Medieval Warm Period (around AD 1000-1250) but precipitation is less. This difference is consistent with the global tropospheric energy budget, which requires a balance between the latent heat released in precipitation and radiative cooling. The tropospheric cooling is less for increased greenhouse gases, which add radiative absorbers to the troposphere, than for increased solar heating, which is concentrated at the Earth's surface. Thus warming due to increased greenhouse gases produces a climate signature different from that of warming due to solar radiation changes.

  17. Cold-induced precipitation of a monoclonal IgM: a negative activation enthalpy reaction.

    PubMed

    Meliga, Stefano C; Farrugia, William; Ramsland, Paul A; Falconer, Robert J

    2013-01-17

    Cold-induced precipitation of a monoclonal IgM cryoglobulin isolated from a patient with Waldenström's macroglobulinemia was observed to have a negative activation enthalpy. The rate of the reaction increased, as the temperature decreased. Differential scanning calorimetry of the monoclonal IgM showed precipitation as an inverted peak during a downward temperature scan. The transition temperature was between 14 and 15 °C and was possibly concentration dependent. At temperatures below the transition the precipitation was best described by second-order kinetics. The difference in change in enthalpy between precipitation and disassociation suggests that cold-induced precipitation had a fast precipitation stage followed by a slower consolidation reaction. Negligible curvature of the Eyring plot suggested the precipitation reaction was dominated by van der Waal forces and hydrogen bonding. Conversely, during an upward temperature scan, disassociation was observed as a positive enthalpy peak. This reaction had two stages, a reaction undoing consolidation followed by heat-induced disassociation that had first-order kinetics.

  18. Irradiation-induced nano-voids in strained tin precipitates in silicon

    NASA Astrophysics Data System (ADS)

    Gaiduk, P. I.; Lundsgaard Hansen, J.; Nylandsted Larsen, A.

    2014-04-01

    We report on self-assembling of spherically shaped voids in nanometer size strained Sn precipitates after irradiation with He+ ions in different conditions. It is found that high-temperature irradiation induces vacancies which are collected by compressively strained Sn precipitates enhancing of out-diffusion of Sn atoms from the precipitates. Nano-voids formation takes place simultaneously with a β- to α-phase transformation in the Sn precipitates. Post-irradiation thermal treatment leads to the removal of voids and a backward transformation of the Sn phase to β-phase. Strain-enhanced separation of point defects along with vacancy assisted Sn out-diffusion and precipitate dissolution are discussed.

  19. Irradiation-induced nano-voids in strained tin precipitates in silicon

    SciTech Connect

    Gaiduk, P. I.; Lundsgaard Hansen, J. Nylandsted Larsen, A.

    2014-04-14

    We report on self-assembling of spherically shaped voids in nanometer size strained Sn precipitates after irradiation with He{sup +} ions in different conditions. It is found that high-temperature irradiation induces vacancies which are collected by compressively strained Sn precipitates enhancing of out-diffusion of Sn atoms from the precipitates. Nano-voids formation takes place simultaneously with a β- to α-phase transformation in the Sn precipitates. Post-irradiation thermal treatment leads to the removal of voids and a backward transformation of the Sn phase to β-phase. Strain-enhanced separation of point defects along with vacancy assisted Sn out-diffusion and precipitate dissolution are discussed.

  20. Structural changes in precipitated silica induced by external forces

    NASA Astrophysics Data System (ADS)

    Schneider, Gerald Johannes; Göritz, Dietmar

    2010-04-01

    The morphology of pure precipitated silica, silica filled in polydimethylsiloxane rubber, and silica filled in styrene butadiene rubber was studied by means of small-angle X-ray scattering experiments. The silica at a length scale of a few nanometers consists of primary particles, which form aggregates, and clusters with aggregates as basic units. It is evidenced that the aggregate branching, represented by the mass fractal dimension, and the aggregate diameter are different if pure silica and silica in rubber are compared. Contrary, the size of the primary particles and their surface are not influenced. It is demonstrated that the change in the aggregate morphology is due to the external mechanical forces appearing during the mixing process. This is achieved by model experiments using a pistil and a mortar and a composite with different silica fractions. By that means, a systematic change in the morphology with grinding time is observed. Then, the experiments on the composite demonstrate that the major contributions to the mass fractal dimensions are due to the external mechanical forces. In order to test reproducibility and universal validity in the case of precipitated silicas, independent experiments on one silica and further silicas are performed. Several important conclusions are obtained from the study. First, it is shown that a comparison of different pure silica samples without knowing their history may be difficult or questionable. Second, it becomes evident that it is not sufficient to provide only a description of the materials, rather than the details of the sample treatment have to be reported. Therefore, solely the characterization of the morphology of the pure silica is not sufficient to be compared to the mechanical properties of the composites.

  1. Wave-induced burst precipitation events detected with a digital ionosonde

    SciTech Connect

    Jarvis, M.J.; Smith, A.J. ); Berkey, F.T. ); Carpenter, D.L. )

    1990-01-01

    Initial results are presented from two methods whereby burst precipitation events in the lower ionosphere, almost certainly induced by VLF wave-particle interactions in the magnetosphere, have been detected using a ground-based digital ionosonde. In the first method, HF echoes are received above the critical frequency of the surrounding plasma; particle energies and the location and extent of the plasma enhancement may be deduced. In the second method, a rapid decrease in the phase of ionospheric echoes is observed due to refractive index changes along the echo path; particle energies, the duration of the precipitation event and the precipitation energy flux can be estimated.

  2. A Search for Wave Induced Particle Precipitation from Lightning and Transmitter Sources

    DTIC Science & Technology

    1988-01-01

    Observed and Modeled Event 50 Transmitter Whistler Sources 58 Summary 60 Chapter 4 The Wave Induced Particle Precipitation Campaign Instrumentation 63...101 ’ iii - k~rUM-rIF%9www Chapter 7 Summary and Conclusions Summary 102 Conclusions 105 Bibliography 107 iv LIST OF TABLES Number Page 1. Model ...Precipitation Bursts 56 2. X-Ray Detector Differential Channels 75 vB -- - -- - LIST OF FIGURES Number Page 1. Global Electrical circuit 2 2. Vertical

  3. Effect of some biotic factors on microbially-induced calcite precipitation in cement mortar.

    PubMed

    Al-Salloum, Yousef; Abbas, H; Sheikh, Q I; Hadi, S; Alsayed, Saleh; Almusallam, Tarek

    2017-02-01

    Sporosarcina pasteurii, a common soil bacterium has been tested for microbial treatment of cement mortar. The present study also seeks to investigate the effects of growth medium, bacterial concentration and different buffers concerning the preparation of bacterial suspensions on the compressive strength of cement mortar. Two growth media, six different suspensions and two bacterial concentrations were used in the study. The influence of growth medium on calcification efficiency of S. pasteurii was insignificant. Significant improvement in the compressive as well as the tensile strength of cement mortar was observed. Microbial mineral precipitation visualized by Scanning Electron Microscopy (SEM) shows fibrous material that increased the strength of cement mortar. Formation of thin strands of fillers observed through SEM micrographs improves the pore structure, impermeability and thus the compressive as well as the tensile strengths of the cement mortar. The type of substrate and its molarity have a significant influence on the strength of cement mortar.

  4. Mixing-induced calcite precipitation and dissolution kinetics in micromodel experiments.

    SciTech Connect

    Valocchi, Albert J.; Dewers, Thomas A.; Dehoff, Karl; Yoon, Hongkyu; Werth, Charles J.

    2010-12-01

    Dissolved CO2 from geological CO2 sequestration may react with dissolved minerals in fractured rocks or confined aquifers and cause mineral precipitation. The overall rate of reaction can be limited by diffusive or dispersive mixing, and mineral precipitation can block pores and further hinder these processes. Mixing-induced calcite precipitation experiments were performed by injecting solutions containing CaCl2 and Na2CO3 through two separate inlets of a micromodel (1-cm x 2-cm x 40-microns); transverse dispersion caused the two solutions to mix along the center of the micromodel, resulting in calcite precipitation. The amount of calcite precipitation initially increased to a maximum and then decreased to a steady state value. Fluorescent microscopy and imaging techniques were used to visualize calcite precipitation, and the corresponding effects on the flow field. Experimental micromodel results were evaluated with pore-scale simulations using a 2-D Lattice-Boltzmann code for water flow and a finite volume code for reactive transport. The reactive transport model included the impact of pH upon carbonate speciation and calcite dissolution. We found that proper estimation of the effective diffusion coefficient and the reaction surface area is necessary to adequately simulate precipitation and dissolution rates. The effective diffusion coefficient was decreased in grid cells where calcite precipitated, and keeping track of reactive surface over time played a significant role in predicting reaction patterns. Our results may improve understanding of the fundamental physicochemical processes during CO2 sequestration in geologic formations.

  5. Characteristics of wind-induced loss of solid precipitation derived from a Norwegian field study

    NASA Astrophysics Data System (ADS)

    Petersen-Øverleir, Asgeir; Wolff, Mareile; Isaksen, Ketil; Ødemark, Karianne; Reitan, Trond; Brækkan, Ragnar

    2016-04-01

    Solid precipitation measurements are known to be plagued by under-catch in windy conditions. Adjustment techniques, either based on a dynamic relationship between under-catch and measured determinants or static corrections, are then typically invoked. Such adjustment procedures, especially if the adjustment algorithm is unfit, introduce notable uncertainties that impact hydrological modelling in snow-dominated regions. In 2010, a test-site was established at a mountain plateau in Haukeli, Telemark, Southern Norway. Precipitation data of automatic gauges were compared with a precipitation gauge located in a Double Fence Inter-comparison Reference (DFIR) wind shield construction that served as the reference. A large number of sensors were additionally monitoring supportive meteorological parameters. The study presented in this poster considers data from three winters that were used to study and determine the wind-induced loss of solid precipitation. A general model framework was proposed, and Bayesian methods were used to objectively choose the most plausible sub-model to describe the loss ratio - wind speed - temperature relationship from the Haukeli data. The derived adjustment function is continuous and accounts for measurements of all types of winter precipitation (from rain to dry snow). The analysis shows a non-linear relationship between the loss ratio and wind speed during significant precipitation events, and there is a clear temperature dependency, believed to be mostly related to the precipitation type. The data also displayed a distinctive scatter that is believed to be an artefact mainly caused by neglecting the varying aerodynamic characteristics of the precipitation particles (for a given temperature) as a determinant. The adjustment formula allowed for the first time to derive an adjustment function with a data-tested validity beyond 8-9 m/s and proved a stabilisation of the wind-induced precipitation loss for higher wind speeds. Preliminary tests of

  6. Bioremediation of strontium (Sr) contaminated aquifer quartz sand based on carbonate precipitation induced by Sr resistant Halomonas sp.

    PubMed

    Achal, Varenyam; Pan, Xiangliang; Zhang, Daoyong

    2012-10-01

    Contamination of aquifers or sediments by radioactive strontium ((90)Sr) is a significant environmental problem. In the present study, microbially induced calcite precipitation (MICP) was evaluated for its potential to remediate strontium from aquifer quartz sand. A Sr resistant urease producing Halomonas sp. was characterized for its potential role in bioremediation. The bacterial strain removed 80% of Sr from soluble-exchangeable fraction of aquifer quartz sand. X-ray diffraction detected calcite, vaterite and aragonite along with calcite-strontianite (SrCO(3)) solid solution in bioremediated sample with indications that Sr was incorporated into the calcite. Scanning electron micrography coupled with energy-dispersive X-ray further confirmed MICP process in remediation. The study showed that MICP sequesters soluble strontium as biominerals and could play an important role in strontium bioremediation from both ecological and greener point of view.

  7. Estimation of the impact of climate change-induced extreme precipitation events on floods

    NASA Astrophysics Data System (ADS)

    Hlavčová, Kamila; Lapin, Milan; Valent, Peter; Szolgay, Ján; Kohnová, Silvia; Rončák, Peter

    2015-09-01

    In order to estimate possible changes in the flood regime in the mountainous regions of Slovakia, a simple physically-based concept for climate change-induced changes in extreme 5-day precipitation totals is proposed in the paper. It utilizes regionally downscaled scenarios of the long-term monthly means of the air temperature, specific air humidity and precipitation projected for Central Slovakia by two regional (RCM) and two global circulation models (GCM). A simplified physically-based model for the calculation of short-term precipitation totals over the course of changing air temperatures, which is used to drive a conceptual rainfall-runoff model, was proposed. In the paper a case study of this approach in the upper Hron river basin in Central Slovakia is presented. From the 1981-2010 period, 20 events of the basin's most extreme average of 5-day precipitation totals were selected. Only events with continual precipitation during 5 days were considered. These 5-day precipitation totals were modified according to the RCM and GCM-based scenarios for the future time horizons of 2025, 2050 and 2075. For modelling runoff under changed 5-day precipitation totals, a conceptual rainfall-runoff model developed at the Slovak University of Technology was used. Changes in extreme mean daily discharges due to climate change were compared with the original flood events and discussed.

  8. Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems.

    PubMed

    Barat, R; Montoya, T; Seco, A; Ferrer, J

    2011-06-01

    The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Reactor (SBR) operated for EBPR and finally validated with two experiments. The precipitation model proposed was able to reproduce the dynamics of amorphous calcium phosphate (ACP) formation and later crystallization to hydroxyapatite (HAP) under different scenarios. The model successfully characterised the EBPR performance of the SBR, including the biological, physical and chemical processes.

  9. Potential CO2 leakage reduction through biofilm-induced calcium carbonate precipitation.

    PubMed

    Phillips, Adrienne J; Lauchnor, Ellen; Eldring, Joachim Joe; Esposito, Richard; Mitchell, Andrew C; Gerlach, Robin; Cunningham, Alfred B; Spangler, Lee H

    2013-01-02

    Mitigation strategies for sealing high permeability regions in cap rocks, such as fractures or improperly abandoned wells, are important considerations in the long term security of geologically stored carbon dioxide (CO(2)). Sealing technologies using low-viscosity fluids are advantageous in this context since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. Using aqueous solutions and suspensions that can effectively promote microbially induced mineral precipitation is one such technology. Here we describe a strategy to homogenously distribute biofilm-induced calcium carbonate (CaCO(3)) precipitates in a 61 cm long sand-filled column and to seal a hydraulically fractured, 74 cm diameter Boyles Sandstone core. Sporosarcina pasteurii biofilms were established and an injection strategy developed to optimize CaCO(3) precipitation induced via microbial urea hydrolysis. Over the duration of the experiments, permeability decreased between 2 and 4 orders of magnitude in sand column and fractured core experiments, respectively. Additionally, after fracture sealing, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO(3) mineralization. These studies suggest biofilm-induced CaCO(3) precipitation technologies may potentially seal and strengthen fractures to mitigate CO(2) leakage potential.

  10. FORWARD AND INVERSE BIO-GEOCHEMICAL MODELING OF MICROBIALLY INDUCED PRECIPITATION IN 0.5M COLUMNAR EXPERIMENTS

    SciTech Connect

    Tammer Barkouki; Brian Martinez; Brina Mortensen; Tess Weathers; Jason DeJong; Nic Spycher; Tim Ginn; Yoshiko Fujita; Robert Smith

    2009-09-01

    Microbial ureolysis-induced calcite precipitation may offer an in situ remediation for heavy metal and radionuclide contamination, as well as an alternative to traditional soil strengthening techniques. A microbially mediated calcite precipitation model was built in TOUGHREACT v2 and calibrated to batch and columnar experimental data. Kinetic ureolysis and calcite precipitation-rate expressions were parameterized by coupling TOUCHREACT with UCODE.

  11. Synthesis, characterizations and anti-bacterial activities of pure and Ag doped CdO nanoparticles by chemical precipitation method

    NASA Astrophysics Data System (ADS)

    Sivakumar, S.; Venkatesan, A.; Soundhirarajan, P.; Khatiwada, Chandra Prasad

    2015-02-01

    In the present study, synthesized pure and Ag (1%, 2%, and 3%) doped Cadmium Oxide (CdO) nanoparticles by chemical precipitation method. Then, the synthesized products were characterized by thermo gravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, Ultra violet-Vis diffused reflectance spectroscopy (UV-Vis-DRS), Scanning electron microscopy (SEM), Energy dispersive X-rays (EDX) spectroscopy, and anti-bacterial activities, respectively. The transition temperatures and phase transitions of Cd(OH)2 to CdO at 400 °C was confirmed by TG-DTA analysis. The XRD patterns show the cubic shape and average particle sizes are 21, 40, 34, and 37 nm, respectively for pure and Ag doped samples. FT-IR study confirmed the presence of CdO and Ag at 677 and 459 cm-1, respectively. UV-Vis-DRS study shows the variation on direct and indirect band gaps. The surface morphologies and elemental analysis have been confirmed from SEM and with EDX. In addition, the synthesized products have been characterized by antibacterial activities against Gram-positive and negative bacteria. Further, the present investigation suggests that CdO nanoparticles have the great potential applications on various industrial and medical fields of research.

  12. Sun-stirred Kraken Mare: Circulation in Titan's seas induced by solar heating and methane precipitation

    NASA Astrophysics Data System (ADS)

    Tokano, T.; Lorenz, R. D.

    2015-10-01

    Density-driven circulation in Titan's seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis force. If instead the sea is turbid and most sunlight is absorbed near the sea surface, the sea gets stratified in warm seasons and the circulation remains weak. Strong summer precipitation at high latitudes causes compositional stratification and increase of the nearsurface methane mole fraction towards the north pole. The resultant latitudinal density contrast drives a meridional overturning with equatorward currents near the sea surface and poleward currents near the sea bottom. Weak precipitation induces gyres rather than meridional overturning.

  13. Study of Bacterial Samples Using Laser Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    W, A. Farooq; M, Atif; W, Tawfik; M, S. Alsalhi; Z, A. Alahmed; M, Sarfraz; J, P. Singh

    2014-12-01

    Laser-induced breakdown spectroscopy (LIBS) technique has been applied to investigate two different types of bacteria, Escherichia coli (B1) and Micrococcus luteus (B2) deposited on glass slides using Spectrolaser 7000. LIBS spectra were analyzed using spectrolaser software. LIBS spectrum of glass substrate was compared with bacteria spectra. Ca, Mg, Na, K, P, S, Cl, Fe, Al, Mn, Cu, C, H and CN-band appeared in bacterial samples in air. Two carbon lines at 193.02 nm, 247.88 nm and one hydrogen line at 656.28 nm with intensity ratios of 1.9, 1.83 and 1.53 appeared in bacterial samples B1 and B2 respectively. Carbon and hydrogen are the important components of the bio-samples like bacteria and other cancer cells. Investigation on LIBS spectra of the samples in He and Ar atmospheres is also presented. Ni lines appeared only in B2 sample in Ar atmosphere. From the present experimental results we are able to show that LIBS technique has a potential in the identification and discrimination of different types of bacteria.

  14. Calcium Carbonate Precipitation by Bacillus and Sporosarcina Strains Isolated from Concrete and Analysis of the Bacterial Community of Concrete.

    PubMed

    Kim, Hyun Jung; Eom, Hyo Jung; Park, Chulwoo; Jung, Jaejoon; Shin, Bora; Kim, Wook; Chung, Namhyun; Choi, In-Geol; Park, Woojun

    2016-03-01

    Microbially induced calcium carbonate precipitation (CCP) is a long-standing but re-emerging environmental engineering process for production of self-healing concrete, bioremediation, and long-term storage of CO2. CCP-capable bacteria, two Bacillus strains (JH3 and JH7) and one Sporosarcina strain (HYO08), were isolated from two samples of concrete and characterized phylogenetically. Calcium carbonate crystals precipitated by the three strains were morphologically distinct according to field emission scanning electron microscopy. Energy dispersive X-ray spectrometry mapping confirmed biomineralization via extracellular calcium carbonate production. The three strains differed in their physiological characteristics: growth at alkali pH and high NaCl concentrations, and urease activity. Sporosarcina sp. HYO08 and Bacillus sp. JH7 were more alkali- and halotolerant, respectively. Analysis of the community from the same concrete samples using barcoded pyrosequencing revealed that the relative abundance of Bacillus and Sporosarcina species was low, which indicated low culturability of other dominant bacteria. This study suggests that calcium carbonate crystals with different properties can be produced by various CCP-capable strains, and other novel isolates await discovery.

  15. Ground Motions Induced by Precipitation and Fluvial Processes: An Example from Taiwan

    NASA Astrophysics Data System (ADS)

    Yang, Chu-Fang; Chi, Wu-Cheng; Lai, Ying-Ju

    2016-04-01

    Ground motions can be induced by weather-related processes. Analyzing such signals might help quantify those natural processes. Here, we used continuous seismic, meteorological and stream data to analyze broadband ground motions during heavy precipitation events in Taiwan. We detected long period seismic signals in drainage basins during two meteorological cases: Typhoon Morakot in 2009 and East Asian rainy season in 2012. The amplitudes of the seismic waveform correlate well with the amount of the precipitation and the derivative of water level and discharge in a nearby river. We proposed that these seismic signals were induced by ground tilt induced by the loading from the increased water volume in the nearby river. Furthermore, we used the seismic data to estimate and quantify the strength of precipitation during such events. The seismically derived precipitation correlates well with the observed meteorological data. It shows that the long period seismic data may be used to monitor rainfall in real-time. Next, we will try to test our tilt hypothesis using other independent datasets.

  16. Direct measurement of precipitate induced strain in an Al-Zn-Mg-Cu alloy with aberration corrected transmission electron microscopy.

    PubMed

    Ying, X R; Du, Y X; Song, M; Lu, N; Ye, H Q

    2016-11-01

    Precipitates and their associated strain fields significantly influence mechanical properties and, consequently, the industrial performance of aluminum alloys. In this work, we present a direct measurement of strains induced by η' and η precipitates in an Al-Zn-Mg-Cu alloy using aberration-corrected high-resolution transmission electron microscopy and quantitative strain analysis. The results demonstrate that the strain induced by precipitates in the Al-Zn-Mg-Cu alloy shows significant tensile strains perpendicular to the longitudinal direction of the precipitate discs on the side of the discs and along the longitudinal direction at both ends of the η' and η precipitates. This strain field can be described by an equivalent dislocation model, in which the lattice mismatch between the precipitate and the matrix is equivalent to a series of dislocation pairs along the precipitate/matrix interfaces.

  17. Atmospheric ionization induced by precipitating electrons: Comparison of CRAC:EPII model with a parametrization model

    NASA Astrophysics Data System (ADS)

    Artamonov, A. A.; Mishev, A. L.; Usoskin, I. G.

    2016-11-01

    Results of a comparison of a new model CRAC:EPII (Cosmic Ray Atmospheric Cascade: Electron Precipitation Induced Ionization) with a commonly used parametric model of atmospheric ionization is presented. The CRAC:EPII is based on a Monte Carlo simulation of precipitating electrons propagation and interaction with matter in the Earth's atmosphere. It explicitly considers energy deposit: ionization, pair production, Compton scattering, generation of Bremsstrahlung high energy photons, photo-ionization and annihilation of positrons, multiple scattering as physical processes accordingly. Propagation of precipitating electrons and their interactions with air is simulated with the GEANT4 simulation tool PLANETOCOSMICS code using NRLMSISE-00 atmospheric model. Ionization yields are computed and compared with a parametrization model for different energies of incident precipitating energetic electrons, using simulated fluxes of mono-energetic particles. A good agreement between the two models is achieved in the mesosphere but the contribution of Bremsstrahlung in the stratosphere, which is not accounted for in the parametric models, is found significant. As an example, we calculated profiles of the ion production rates in the middle and upper atmosphere (below 100 km) on the basis of balloon-born measured spectra of precipitating electrons for 30-October-2002 and 07-January-2004.

  18. The variability of temperature and precipitation over Korean Peninsula induced by off-equatorial western Pacific precipitation during boreal summer

    NASA Astrophysics Data System (ADS)

    Jeong, Yerim; Ham, Yoo-Geun

    2016-04-01

    The convection activity and variability are active in Tropic-subtropic area because of equatorial warm pool. The variability's impacts on not only subtropic also mid-latitude. The impact effects on through teleconnection between equatorial and mid-latitude like Pacific-Japan(PJ) pattern. In this paper, two groups are divided based on PJ pattern and JJA Korean precipitation for the analysis that Korean precipitation is affected by PJ pattern. 'PJ+NegKorpr' is indicated when PJ pattern occur that JJA(Jun-July_August) Korean precipitation has negative value. In this case, positive precipitation in subtropic is expanded to central Pacific. And the positive precipitation's pattern is increasing toward north. Because, the subtropical south-eastly wind is forming subtropical precipitation's pattern through cold Kelvin wave is expanding eastward. Cold Kelvin wave is because of Indian negative SST. Also, Korea has negative moisture advection and north-eastly is the role that is moving high-latitude's cold and dry air to Korea. So strong high pressure is formed in Korea. The strong high pressure involves that short wave energy is increasing on surface. As a result, The surface temperature is increased on Korea. But the other case, that 'PJ_Only' case, is indicated when PJ pattern occur and JJA Korean precipitation doesn't have negative value over significant level. The subtropic precipitation's pattern in 'PJ_Only' shows precipitation is confined in western Pacific and expended northward to 25°N near 130°E. And tail of precipitation is toward equatorial(south-eastward). Also, Korean a little positive moisture advection and south-westly is the role that is moving low-latitude's warm and wet air to Korea. So weak high pressure is formed in Korea. The weak high pressure influence amount of short wave energy, so Korean surface temperature is lower. In addition, the case of 'PJ_Only' and Pacific Decal Oscillation(PDO) are occur at the same time has negative impact in Korea

  19. Precipitation of energetic neutral atoms and induced non-thermal escape fluxes from the Martian atmosphere

    SciTech Connect

    Lewkow, N. R.; Kharchenko, V.

    2014-08-01

    The precipitation of energetic neutral atoms, produced through charge exchange collisions between solar wind ions and thermal atmospheric gases, is investigated for the Martian atmosphere. Connections between parameters of precipitating fast ions and resulting escape fluxes, altitude-dependent energy distributions of fast atoms and their coefficients of reflection from the Mars atmosphere, are established using accurate cross sections in Monte Carlo (MC) simulations. Distributions of secondary hot (SH) atoms and molecules, induced by precipitating particles, have been obtained and applied for computations of the non-thermal escape fluxes. A new collisional database on accurate energy-angular-dependent cross sections, required for description of the energy-momentum transfer in collisions of precipitating particles and production of non-thermal atmospheric atoms and molecules, is reported with analytic fitting equations. Three-dimensional MC simulations with accurate energy-angular-dependent cross sections have been carried out to track large ensembles of energetic atoms in a time-dependent manner as they propagate into the Martian atmosphere and transfer their energy to the ambient atoms and molecules. Results of the MC simulations on the energy-deposition altitude profiles, reflection coefficients, and time-dependent atmospheric heating, obtained for the isotropic hard sphere and anisotropic quantum cross sections, are compared. Atmospheric heating rates, thermalization depths, altitude profiles of production rates, energy distributions of SH atoms and molecules, and induced escape fluxes have been determined.

  20. Ethanol or/and captopril-induced precipitation and secondary conformational changes of human serum albumin

    NASA Astrophysics Data System (ADS)

    Lin, Shan-Yang; Li, Mei-Jane; Wei, Yen-Shan

    2004-11-01

    We determined the secondary structure of solid-state native human serum albumin (HSA) and its precipitates induced by ethanol, captopril, or a captopril/ethanol mixture. A transmission Fourier transform infrared (FT-IR) microspectroscopy equipped with a thermal analyzer was used. The secondary structural composition of solid-state native HSA was 54% α-helices (1655 cm -1), 22% β-turns (1679 cm -1), and 23% β-sheets (1633 cm -1). After ethanol treatment, a new peak was observed at 1690 cm -1, and the peak at 1633 cm -1 was more apparent in the HSA precipitates. The corresponding compositions consisted of 59% α-helices, 17% β-turns, and 24% β-sheets. After treatment with captopril with or without ethanol, the percentage of α-helices and β-turns decreased in both HSA precipitates, but the percentage of β-sheets increased. The temperature-dependent structural transformation from α-helices/random coils to β-sheets for the solid-state HSA samples occurred at markedly different onset temperatures. The onset temperature for native HSA was 85 °C, and that for HSA precipitates obtained from ethanol, captopril, or captopril/ethanol was 100, 48 or 57 °C, respectively. The thermal-induced structural transformation from α-helices/random coils to β-sheets implies a partial unfolding structure in these HSA samples.

  1. Effects of turbulence-induced collision enhancement on heavy precipitation: The 21 September 2010 case over the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Lee, Hyunho; Baik, Jong-Jin

    2016-10-01

    The effects of turbulence-induced collision enhancement (TICE) on a heavy precipitation event that occurred on 21 September 2010 over the middle Korean Peninsula are examined. For this purpose, an updated bin microphysics scheme incorporating TICE for drop-drop and drop-graupel collisions is implemented into the Weather Research and Forecasting (WRF) model. The numerical simulation shows some differences in the strong precipitation system compared to the observations but generally captures well the important features of observed synoptic conditions, surface precipitation, and radar reflectivity. While the change in domain-averaged surface precipitation amount due to TICE is small and similar to that due to small initial perturbations, the spatial distribution of surface precipitation amount is somewhat altered due to TICE. The surface precipitation amount is increased due to TICE in the area where the largest surface precipitation occurred, but the effects of different flow realizations also contribute to the changes. TICE accelerates the coalescence between small cloud droplets, which induces a decrease in condensation and an increase in excess water vapor transported upward. This causes an increase in relative humidity with respect to ice at high altitudes, hence increasing the depositional growth of ice particles. Therefore, the ice mass increases due to TICE, and this increase induces the increases in riming and melting of ice particles. A series of these microphysical changes due to TICE are regarded as partially contributing to the increase in surface precipitation amount in some areas, hence inducing alterations in the spatial distribution of surface precipitation amount.

  2. Femtosecond laser filament induced condensation and precipitation in a cloud chamber

    PubMed Central

    Ju, Jingjing; Liu, Jiansheng; Liang, Hong; Chen, Yu; Sun, Haiyi; Liu, Yonghong; Wang, Jingwei; Wang, Cheng; Wang, Tiejun; Li, Ruxin; Xu, Zhizhan; Chin, See Leang

    2016-01-01

    A unified picture of femtosecond laser induced precipitation in a cloud chamber is proposed. Among the three principal consequences of filamentation from the point of view of thermodynamics, namely, generation of chemicals, shock waves and thermal air flow motion (due to convection), the last one turns out to be the principal cause. Much of the filament induced chemicals would stick onto the existing background CCN’s (Cloud Condensation Nuclei) through collision making the latter more active. Strong mixing of air having a large temperature gradient would result in supersaturation in which the background CCN’s would grow efficiently into water/ice/snow. This conclusion was supported by two independent experiments using pure heating or a fan to imitate the laser-induced thermal effect or the strong air flow motion, respectively. Without the assistance of any shock wave and chemical CCN’s arising from laser filament, condensation and precipitation occurred. Meanwhile we believe that latent heat release during condensation /precipitation would enhance the air flow for mixing. PMID:27143227

  3. Femtosecond laser filament induced condensation and precipitation in a cloud chamber

    NASA Astrophysics Data System (ADS)

    Ju, Jingjing; Liu, Jiansheng; Liang, Hong; Chen, Yu; Sun, Haiyi; Liu, Yonghong; Wang, Jingwei; Wang, Cheng; Wang, Tiejun; Li, Ruxin; Xu, Zhizhan; Chin, See Leang

    2016-05-01

    A unified picture of femtosecond laser induced precipitation in a cloud chamber is proposed. Among the three principal consequences of filamentation from the point of view of thermodynamics, namely, generation of chemicals, shock waves and thermal air flow motion (due to convection), the last one turns out to be the principal cause. Much of the filament induced chemicals would stick onto the existing background CCN’s (Cloud Condensation Nuclei) through collision making the latter more active. Strong mixing of air having a large temperature gradient would result in supersaturation in which the background CCN’s would grow efficiently into water/ice/snow. This conclusion was supported by two independent experiments using pure heating or a fan to imitate the laser-induced thermal effect or the strong air flow motion, respectively. Without the assistance of any shock wave and chemical CCN’s arising from laser filament, condensation and precipitation occurred. Meanwhile we believe that latent heat release during condensation /precipitation would enhance the air flow for mixing.

  4. Femtosecond laser filament induced condensation and precipitation in a cloud chamber.

    PubMed

    Ju, Jingjing; Liu, Jiansheng; Liang, Hong; Chen, Yu; Sun, Haiyi; Liu, Yonghong; Wang, Jingwei; Wang, Cheng; Wang, Tiejun; Li, Ruxin; Xu, Zhizhan; Chin, See Leang

    2016-05-05

    A unified picture of femtosecond laser induced precipitation in a cloud chamber is proposed. Among the three principal consequences of filamentation from the point of view of thermodynamics, namely, generation of chemicals, shock waves and thermal air flow motion (due to convection), the last one turns out to be the principal cause. Much of the filament induced chemicals would stick onto the existing background CCN's (Cloud Condensation Nuclei) through collision making the latter more active. Strong mixing of air having a large temperature gradient would result in supersaturation in which the background CCN's would grow efficiently into water/ice/snow. This conclusion was supported by two independent experiments using pure heating or a fan to imitate the laser-induced thermal effect or the strong air flow motion, respectively. Without the assistance of any shock wave and chemical CCN's arising from laser filament, condensation and precipitation occurred. Meanwhile we believe that latent heat release during condensation /precipitation would enhance the air flow for mixing.

  5. Sensitivity of the Tropical Pacific Ocean to Precipitation Induced Freshwater Flux

    NASA Technical Reports Server (NTRS)

    Yang, Song; Lau, K.-M.; Schopf, Paul S.

    1999-01-01

    We have performed a series of experiments using an ocean model to study the sensitivity of tropical Pacific Ocean to variations in precipitation induced freshwater fluxes. Variations in these fluxes arise from natural causes on all time scales. In addition, estimates of these fluxes are uncertain because of differences among measurement techniques. The model used is a quasi-isopycnal model, covering the Pacific from 40 S to 40 N. The surface forcing is constructed from observed wind stress, evaporation, precipitation, and surface temperature (SST) fields. The heat flux is produced with an iterative technique so as to maintain the model close to the observed climatology, but with only a weak damping to that climatology. Climatological estimates of evaporation are combined with various estimates of precipitation to determine the net surface freshwater flux. Results indicate that increased freshwater input decreases salinity as expected, but increases temperatures in the upper ocean. Using the freshwater flux estimated from the Microwave Sounding Unit leads to a warming of up to 0.6 C in the western Pacific over a case with zero net freshwater flux. SST is sensitive to the discrepancies among different precipitation observations, with root-mean-square differences in SST on the order of 0.2-0.3 C. The change in SST is more pronounced in the eastern Pacific, with differences of over 1 C found among the various precipitation products. Interannual variation in precipitation during El Nino events leads to increased warming. During the winter of 1982-83, freshwater flux accounts for about 0.4 C (approximately 10-15% of the maximum warming) of the surface warming in the central-eastern Pacific. Thus, the error of SST caused by the discrepancies in precipitation products is more than half of the SST anomaly produced by the interannual variability of observed precipitation. Further experiments, in which freshwater flux anomalies are imposed in the western, central, and eastern

  6. Irradiation-induced precipitation and mechanical properties of vanadium alloys at <430 C

    SciTech Connect

    Chung, H.M.; Gazda, J.; Smith, D.L.

    1998-09-01

    Recent attention to V-base alloys has focused on the effect of low-temperature (<430 C) irradiation on tensile and impact properties of V-4Cr-4Ti. In previous studies, dislocation channeling, which causes flow localization and severe loss of work-hardening capability, has been attributed to dense, irradiation-induced precipitation of very fine particles. However, efforts to identify the precipitates were unsuccessful until now. In this study, analysis by transmission electron microscopy (TEM) was conducted on unalloyed V, V-5Ti, V-3Ti-1Si, and V-4Cr-4Ti specimens that were irradiated at <430 C in conventional and dynamic helium charging experiments. By means of dark-field imaging and selected-area-diffraction analysis, the characteristic precipitates were identified to be (V,Ti{sub 1{minus}x})(C,O,N). In V-3Ti-1Si, precipitation of (V,Ti{sub 1{minus}x})(C,O,N) was negligible at <430 C, and as a result, dislocation channeling did not occur and work-hardening capability was high.

  7. Ifosfamide-induced Encephalopathy Precipitated by Aprepitant: A Rarely Manifested Side Effect of Drug Interaction

    PubMed Central

    Kataria, Pritam Sureshchandra; Kendre, Pradip Piraji; Patel, Apurva A.

    2017-01-01

    Central nervous system (CNS) toxicity has been reported in approximately 10%–30% of patients receiving intravenous infusions of ifosfamide. Encephalopathy is a rare but serious CNS adverse reaction in these patients, and although usually transient and reversible, may cause persistent neurological dysfunction or death. Clinical features range from fatigue and confusion to coma and death. Ifosfamide forms backbone of various treatment regimens including curative treatment and palliative chemotherapy regimen. Precipitation of ifosfamide-induced encephalopathy (IIE) by aprepitant has been reported in the literature rarely. Ifosfamide is moderately emetogenic; hence, aprepitant is used to prevent emesis induced by ifosfamide. We here report a case where a patient of recurrent B-cell Philadelphia-negative acute lymphoblastic lymphoma was given aprepitant to prevent ifosfamide-induced emesis. After 24 h of ifosfamide infusion, the patient developed symptoms of encephalopathy, i.e., headache, vomiting, and one episode of seizure which was followed by disoriented behavior. After doing all routine investigations and neuroimaging, the diagnosis of IIE was kept on clinical grounds, and after looking for the various factors, we came across injection fosaprepitant as the precipitating factor. On the clinical grounds, the patient was treated with hydration and injection methylene blue for above complaints, and the patient recovered without any residual deficit within 48–72 h. Hence, in the presence of causative agent, i.e., ifosfamide and precipitating agent injection fosaprepitant with negative imaging and normal laboratory parameters as well as the early and good response to methylene blue, the diagnosis of IIE precipitated by aprepitant was confirmed.

  8. A quantitative analysis of microbially-induced calcite precipitation employing artificial and naturally-occurring sediments

    NASA Astrophysics Data System (ADS)

    Lokier, Stephen; Krieg Dosier, Ginger

    2013-04-01

    Microbially-induced calcite precipitation is a strong candidate for the production of sustainable construction materials. The process employs the microbe Sporosarcina pasteurii as an agent to microbially mediate the precipitation of calcium carbonate to bind unconsolidated sediment. As this process can be achieved under ambient temperature conditions and can utilise a wide variety of easily-available sediments, potentially including waste materials, it is envisioned that this procedure could significantly reduce carbon-dioxide emissions in the construction industry. This study describes and quantifies the precipitation of calcite cement in a range of naturally-occurring sediments compared with a control matrix. The study establishes the optimum treatment time for effective cement precipitation in order to produce a material that meets the standards required for construction whilst keeping economic and environmental outlays at a minimum. The 'control sediment' employed industrial-grade glass beads with a grain size range of 595-1180 microns (16-30 US mesh). Sporosarcina pasteurii were mixed in a solution of urea and calcium chloride and then inoculated into the control sediment. The microbes attach to the surface of the sediment grains and employ urea as a source of energy to produce ammonia and carbon dioxide. By so doing, they increase the pH of the solution allowing calcium carbonate to precipitate at the cell walls to act as nucleation points facilitating the precipitation of cements as a grain-coating and biocementing the unconsolidated sediment. The solution treatment was repeated at eight hour intervals with samples removed for detailed analysis after each every five consecutive treatments (i.e. 40 hours). The process was repeated to produce 20 samples with treatment times between 40 and 800 hours. Cemented samples were impregnated with blue epoxy and examined petrographically to monitor cement development. Modal analysis was undertaken on each cemented

  9. Fungal innate immunity induced by bacterial microbe-associated molecular patterns (MAMPs)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants and animals detect bacterial presence through Microbe-Associated Molecular Patterns (MAMPs) which induce an innate immune response. The field of fungal-bacterial interaction at the molecular level is still in its infancy and very little is known about fungal molecular responses to bacteria, a...

  10. Search for lightning-induced electron precipitation with rocket-borne photometers

    SciTech Connect

    Massey, R.D.; McCarthy, M.P.; Parks, G.K.

    1990-11-01

    Photometers at 3,914{angstrom} and 5,577{angstrom} and an optical imager were part of an experimental package launched on a sounding rocket in the 1987 Wave Induced Particle Precipitation (WIPP) campaign at Wallops Island, Virginia. The objective was to measure lightning-induced electron precipitation (LEP) by means of its optical signature. This was the first attempt to measure LEP using rocket-borne optical instrumentation. Launch criteria included nearby thunderstorm activity and ground-based observations of Trimpi events. Lightning flashes are clearly discernible in the data. The photometer data was also characterized by large spin and precession modulations in the photon count rate, consistent with elevated steady particle fluxes in the northern portion of the instrument field of view. No evidence of LEP was observed by the photometers or onboard particle detectors (Arnoldy and Kinter, 1989). Analysis of the data has enabled the authors to place an upper limit of 8 {times} 10{sup {minus}4} ergs-cm{sup {minus}2}-sec{sup {minus}1} on any burst precipitation energy flux that many have occurred during the rocket flight in the regions explored by the photometers.

  11. Orientation relationship formed during irradiation induced precipitation of W in Cu

    NASA Astrophysics Data System (ADS)

    Tai, Kaiping; Averback, Robert S.; Bellon, Pascal; Vo, Nhon; Ashkenazy, Yinon; Dillon, Shen J.

    2014-11-01

    Irradiation of dilute Cu-W alloys with 1.8 MeV Kr+ between 300 K and 573 K is found to induce nucleation of a high density of W nano-precipitates. HRTEM and aberration-corrected STEM reveal that the ∼3 nm precipitates have a preferred orientation relationship with the matrix. A variant of the Bain relationship exists with preferred alignment occurring along Cu<2 2 0> || W<010>, with small angular differences amongst the particles, which is compensated by interfacial dislocations or strain. The formation mechanism for such an orientation relationship is rationalized on the basis that small W clusters form within the local melt of an energetic displacements cascade, resulting in the partial alignment of the nanoprecipitates with the Cu lattice as the Cu solidifies.

  12. Image-based Modeling of Biofilm-induced Calcium Carbonate Precipitation

    NASA Astrophysics Data System (ADS)

    Connolly, J. M.; Rothman, A.; Jackson, B.; Klapper, I.; Cunningham, A. B.; Gerlach, R.

    2013-12-01

    Pore scale biological processes in the subsurface environment are important to understand in relation to many engineering applications including environmental contaminant remediation, geologic carbon sequestration, and petroleum production. Specifically, biofilm induced calcium carbonate precipitation has been identified as an attractive option to reduce permeability in a lasting way in the subsurface. This technology may be able to replace typical cement-based grouting in some circumstances; however, pore-scale processes must be better understood for it to be applied in a controlled manor. The work presented will focus on efforts to observe biofilm growth and ureolysis-induced mineral precipitation in micro-fabricated flow cells combined with finite element modelling as a tool to predict local chemical gradients of interest (see figure). We have been able to observe this phenomenon over time using a novel model organism that is able to hydrolyse urea and express a fluorescent protein allowing for non-invasive observation over time with confocal microscopy. The results of this study show the likely existence of a wide range of local saturation indices even in a small (1 cm length scale) experimental system. Interestingly, the locations of high predicted index do not correspond to the locations of higher precipitation density, highlighting the need for further understanding. Figure 1 - A micro-fabricated flow cell containing biofilm-induced calcium carbonate precipitation. (A) Experimental results: Active biofilm is in green and dark circles are calcium carbonate crystals. Note the channeling behavior in the top of the image, leaving a large hydraulically inactive area in the biofilm mass. (B) Finite element model: The prediction of relative saturation of calcium carbonate (as calcite). Fluid enters the system at a low saturation state (blue) but areas of high supersaturation (red) are predicted within the hydraulically inactive area in the biofilm. If only effluent

  13. Harnessing a radiation inducible promoter of Deinococcus radiodurans for enhanced precipitation of uranium.

    PubMed

    Misra, Chitra Seetharam; Mukhopadhyaya, Rita; Apte, Shree Kumar

    2014-11-10

    Bioremediation is an attractive option for the treatment of radioactive waste. We provide a proof of principle for augmentation of uranium bioprecipitation using the radiation inducible promoter, Pssb from Deinococcus radiodurans. Recombinant cells of D. radiodurans carrying acid phosphatase gene, phoN under the regulation of Pssb when exposed to 7 kGy gamma radiation at two different dose rates of 56.8 Gy/min and 4 Gy/min, showed 8-9 fold increase in acid phosphatase activity. Highest whole cell PhoN activity was obtained after 2h in post irradiation recovery following 8 kGy of high dose rate radiation. Such cells showed faster removal of high concentrations of uranium than recombinant cells expressing PhoN under a radiation non-inducible deinococcal promoter, PgroESL and could precipitate uranium even after continuous exposure to 0.6 Gy/min gamma radiation for 10 days. Radiation induced recombinant D. radiodurans cells when lyophilized retained high levels of PhoN activity and precipitated uranium efficiently. These results highlight the importance of using a suitable promoter for removal of radionuclides from solution.

  14. Numerical investigation of microbially induced calcite precipitation as a leakage mitigation technology

    NASA Astrophysics Data System (ADS)

    Hommel, Johannes; Cunningham, Alfred; Helmig, Rainer; Ebigbo, Anozie; Class, Holger

    2013-04-01

    One of the key issues of carbon capture and storage (CCS) is the long term security of the storage site, i.e. the permanent enclosure of the stored carbon dioxide (CO2) in the target reservoir. Amongst the different storage mechanisms, cap rock integrity is crucial for preventing leakage of CO2. Leakage to shallower regions or back to the atmosphere would reduce the efficiency and pose a threat to the environment, for example to groundwater resources or human residence areas. Ureolysis-driven microbially induced calcite precipitation (MICP) is one of the technologies in the current focus of research aiming at mitigation of potential leakage by sealing high permeability zones in cap rocks. In our current work, a numerical model has been developed and validated using MICP experiments in sand filled columns under atmospheric pressure conditions [1]. Based on new experimental data under reservoir pressure conditions in sandstone rock cores [2] the model will be improved and optimized. The focus is on extending the model to 3-D radial flow and the validation of the model under conditions relevant for field scale CCS. The improved numerical model will be used to design field scale MICP experiments and evaluate the results of those experiments to get a better understanding of the potential of MICP as a sealing technology. [1] Ebigbo A., Phillips A., Gerlach R., Helmig R., Cunningham A.B., Class H., and Spangler L. H. (2012), Darcy-scale modeling of microbially induced carbonate mineral precipitation in sand columns, Water Resour. Res., 48 [2] Phillips A., Lauchnor E., Eldring J., Esposito R., Mitchell A.C., Gerlach R., Cunningham A.B., and Spangler L. H. (2013), Potential CO2 leakage reduction through biofilm-induced calcium carbonate precipitation, Environ. Sci. Technol., 47(1)

  15. Sun-stirred Kraken Mare: Circulation in Titan's seas induced by solar heating and methane precipitation

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya; Lorenz, Ralph D.

    2016-05-01

    Density-driven circulation in Titan's seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis force. If instead the sea is turbid and most sunlight is absorbed near the sea surface, the sea gets stratified in warm seasons and the circulation remains weak. Precipitation causes compositional stratification of the sea to an extent that the sea surface temperature can be lower than the sea interior temperature without causing a convective overturning. Non-uniform precipitation can also generate a latitudinal gradient in the methane mole fraction and density, which drives a meridional overturning with equatorward currents near the sea surface and poleward currents near the sea bottom. However, gyres are more ubiquitous than meridional overturning.

  16. Assessing Flood Risk from Hurricane-induced Precipitation and Storm Surge: A Bayesian Network Approach

    NASA Astrophysics Data System (ADS)

    Sebastian, A.; Dupuits, E. J. C.; Morales-Napoles, O.

    2015-12-01

    Hurricanes pose a major flood hazard to communities on the U.S. Atlantic and Gulf Coasts. Over the past decade, the economic costs associated with hurricane flood damages have escalated and recent studies indicate that a large percentage of flood damages are occurring outside of FEMA-designated flood hazard areas. While FEMA recently upgraded coastal flood hazard maps using the Advanced CIRCulation (ADCIRC) Model, these maps do not consider the flood hazard resulting from the joint occurrence of precipitation over the watershed and storm surge at the coast. Instead, the two individual hazards are mapped separately, ignoring the floodplain resulting from their interaction.In this study, a risk assessment methodology was developed to predict the damages associated with hurricane-induced flooding in the Houston Galveston Bay Area. Historical hurricanes were analyzed to derive probability distributions for storm surge height, cumulative precipitation, hurricane landfall, wind speed, angle of approach, radius to maximum winds, and forward speed. A Bayesian Network was built and used to simulate a large number of synthetic storms. The resulting 1% combinations of storm surge and precipitation were applied as boundary conditions to a hydraulic modeled and the maximum extent of flooding was compared to the FEMA-designated flood hazard areas. A high resolution GIS-based model was used to predict damages.

  17. Spectral Induced Polarization Signatures of Hydroxide Adsorption and Mineral Precipitation in Porous Media

    SciTech Connect

    Zhang, Chi; Slater, Lee; Redden, George D.; Fujita, Yoshiko; Johnson, Timothy C.; Fox, Don

    2012-04-17

    The spectral induced polarization (SIP) technique is a promising approach for delineating subsurface physical and chemical property changes in a minimally invasive manner. To facilitate the understanding of position and chemical properties of reaction fronts that involve mineral precipitation in porous media, we investigated spatiotemporal variations in complex conductivity during evolution of urea hydrolysis and calcite precipitation reaction fronts within a silica gel column. The real and imaginary parts of complex conductivity were shown to be sensitive to changes in both solution chemistry and calcium carbonate precipitation. Distinct changes in imaginary conductivity coincided with increased hydroxide ion concentration during urea hydrolysis. In a separate experiment focused on the effect of hydroxide concentration on interfacial polarization of silica gel and well-sorted sand, we found a significant dependence of the polarization response on pH changes of the solution. We propose a conceptual model describing hydroxide ion adsorption behavior in silica gel and its control on interfacial polarizability. Our results demonstrate the utility of SIP for noninvasive monitoring of reaction fronts, and indicate its potential for quantifying geochemical processes that control the polarization responses of porous media at larger spatial scales in the natural environment.

  18. Global and Seasonal Assessments of Magnetosphere / Ionosphere Coupling via Lightning-Induced Electron Precipitation

    NASA Astrophysics Data System (ADS)

    Sousa, Austin; Marshall, Robert; Close, Sigrid

    2016-07-01

    Pitch-angle scattering by radio waves in the VLF (~3-30kHz) band is thought to be a major loss mechanism for energetic radiation-belt electrons. Resonant interactions with Whistler-mode VLF waves can alter the reflection altitude of trapped electrons ~100keV - 1MeV; when a particle reflects at a low enough altitude, it can be removed from the magnetosphere through collisions with ionospheric constituents. Terrestrial lightning provides a natural and constantly-occurring source of VLF waves. Here we present a global assessment of lightning-induced electron precipitation (LEP) due to resonant pitch-angle scattering from whistler-mode waves, which represent a coupling process between the magnetosphere and ionosphere. We combine an end-to-end model of the LEP process with terrestrial lightning activity data from the GLD360 sensor network to construct a realtime geospatial model of LEP-driven energy deposition into the ionosphere. We explore global and seasonal statistics, provide precipitation estimates across a variety of magnetospheric conditions, and compare the total impact to other magnetospheric loss processes. Additionally, we use our model to optimize event selection from the energetic-particle detectors on board the FIREBIRD CubeSats, in order to download data over the satellite's low-bandwidth downlink. Ultimately, FIREBIRD data will be used to validate our model, and to provide one-to-one correlative measurements of lightning strokes and subsequent precipitation.

  19. Monitoring Microbe-Induced Sulfide Precipitation Under Dynamic Flow Conditions Using Multiple Geophysical Techniques

    NASA Astrophysics Data System (ADS)

    Williams, K. H.; Hubbard, S.; Ntarlagiannis, D.; Banfield, J.

    2004-05-01

    A laboratory study was undertaken to investigate the feasibility of using minimally invasive geophysical techniques to monitor microbe-induced sulfide precipitation in saturated sand-packed columns under dynamic flow conditions. Specifically, the effect of zinc and iron sulfide precipitation on geophysical signatures was evaluated during stimulated sulfate-reduction by Desulfovibrio vulgaris. Four inoculated columns and one non-inoculated control were operated under a continuous upward flow velocity of 50cm/day with the following measurements made: multi-port fluid sampling, cross-column acoustic wave propagation, induced polarization, time domain reflectometry and saturated hydraulic conductivity. Over a period of seven weeks, the onset and progression of sulfate reduction within the columns was confirmed through decreasing substrate and aqueous metals concentrations, increased biomass, and visible regions of sulfide accumulation. Decreases in initial lactate and sulfate concentrations (2.8mM and 4.0mM, respectively) followed predicted stoichiometric relationships and soluble Zn(II) and Fe(II) concentrations (0.31mM and 0.36mM, respectively) were reduced to levels below detection through sequestration as insoluble sulfide phases. The areas where sulfide precipitation and accumulation occurred resulted in significant changes in two of the three geophysical measurements. High frequency (400-600kHz) acoustic wave amplitudes were reduced by nearly an order of magnitude over the course of the experiment with no significant accompanying change in wave velocity. Neither the wave amplitudes nor the velocities changed significantly in the downgradient portions of the column where microbial activity and sulfide precipitation were depressed due to depleted substrate and metals concentrations. The frequency content of the transmitted waves remained unchanged throughout the course of the experiment. Over the frequency range of the induced polarization measurements (0.1-1000Hz

  20. Pulsed laser-induced epitaxy and precipitation of group IV alloys

    NASA Astrophysics Data System (ADS)

    Kramer, Kenneth Michael

    Substitutional Sisb{1-x}Csb{x} solutions produced by pulsed laser induced epitaxy of ion implanted Si were studied in the concentration range from 0.35 to 3.8 at.% C. Films were formed by multiple energy ion implantation of carbon into \\{001\\} Si to produce nearly uniform composition profiles, followed by irradiation with a 308 nm, 30 ns excimer laser pulse. Heteroepitaxy proceeded from the underlying \\{001\\} Si through the carbon containing layer at approximately 4 m/s. The diffusion coefficient was determined as ˜2 × 10sp{-4} cmsp2 ssp{-1} by comparison of secondary-ion mass spectrometry (SIMS) profiles with numerical calculations. Non-equilibrium carbon segregation was observed with a segregation coefficient >0.4 estimated from the SIMS profiles. At 1.4 at.% C, SIMS profiles display an immobile carbon component at the peak carbon concentrations. Transmission electron microscopy (TEM) reveals an areal precipitate density of about 4 × 10sp9 cmsp{-2} at 1.4 at.% C, far less than necessary to account for the anomalous diffusion behavior. At 2.1 at.% C, randomly oriented SiC precipitates are identified with diameters ranging from 5 to 7 nm and areal densities of 6 × 10sp{11} cmsp{-2}. Layers with up to 2.1 at.% C are free of dislocations and stacking faults; at 3.8 at.% C both precipitates and dislocations were observed. Numerical calculations of heat and mass diffusion were combined with classical nucleation theory to model the SiC precipitation kinetics in Si-C solutions during laser annealing. Comparison of experimental observations with model calculations resulted in an estimate for the SiC-liquid surface energy between 0.53 to 0.56 J msp{-2}. The model predicts higher precipitate densities with decreasing pulse width and increasing laser energy density. A factor of 10 difference between calculated and TEM measured precipitate densities was found and sources of this discrepancy are discussed. Pulsed laser recrystallization and solid-phase epitaxy (SPE) of

  1. Endomorphin-1 and -2 induce naloxone-precipitated withdrawal syndromes in rats.

    PubMed

    Chen, J-C; Tao, P-L; Li, J-Y; Wong, C-H; Huang, E Y-K

    2003-03-01

    In 1997, endomorphin-1 (EM-1) and -2 (EM-2) were identified as the most specific endogenous mu-opioid ligands. These two peptides have shown analgesic effects and many other opioid functions. In the present study, we attempt to investigate the possible ability of endomorphins to induce naloxone-precipitated withdrawal in comparison with that induced by morphine. Using the previously established scoring system in rats, 12 withdrawal signs (chewing, sniffing, grooming, wet-dog shakes, stretching, yawning, rearing, jumping, teeth grinding, ptosis, diarrhea, and penile erection) were observed and scored following naloxone (4 mg/kg, i.p.) challenge. Compared with the sham control, EM-1 and EM-2 (20 microg, i.c.v., b.i.d. for 5 days) both produced significant naloxone-induced withdrawal syndromes with similar severity to that induced by the same dose of morphine. There was no significant difference between EM-1, EM-2, and morphine-treated group for naloxone-induced withdrawal signs, except for grooming. EM-1 and EM-2 induced more grooming than that caused by morphine. Although EM-1 and EM-2 both led to the withdrawal, they displayed different potency for certain signs and suggest their distinct regulations. The present results indicate EM-1 and EM-2 could initiate certain mechanism involved opiate dependence.

  2. Bacterial Flora Changes in Conjunctiva of Rats with Streptozotocin-Induced Type I Diabetes

    PubMed Central

    Qin, Yali; Luo, Dan; Yang, Shufei; Kou, Xinyun; Zi, Yingxin; Deng, Tingting; Jin, Ming

    2015-01-01

    Background The microbiota of both humans and animals plays an important role in their health and the development of disease. Therefore, the bacterial flora of the conjunctiva may also be associated with some diseases. However, there are no reports on the alteration of bacterial flora in conjunctiva of diabetic rats in the literature. Therefore, we investigated the changes in bacterial flora in bulbar conjunctiva of rats with streptozotocin (STZ)-induced type I diabetes. Methods A high dose of STZ (60 mg/kg, i.p.) was injected into Sprague-Dawley (SD) rats to induce type I diabetes mellitus (T1DM). The diabetic rats were raised in the animal laboratory and at 8 months post-injection of STZ swab samples were taken from the bulbar conjunctiva for cultivation of aerobic bacteria. The bacterial isolates were identified by Gram staining and biochemical features. The identified bacteria from both diabetic and healthy rats were then compared. Results The diabetic and healthy rats had different bacterial flora present in their bulbar conjunctiva. In total, 10 and 8 bacterial species were found in the STZ and control groups, respectively, with only three species (Enterococcus faecium, Enterococcus gallinarum and Escherichia coli) shared between the two groups. Gram-positive bacteria were common in both groups and the most abundant was Enterococcus faecium. However, after the development of T1DM, the bacterial flora in the rat bulbar conjunctiva changed considerably, with a reduced complexity evident. Conclusions STZ-induced diabetes caused alterations of bacterial flora in the bulbar conjunctiva in rats, with some bacterial species disappearing and others emerging. Our results indicate that the conjunctival bacterial flora in diabetic humans should be surveyed for potential diagnostic markers or countermeasures to prevent eye infections in T1DM patients. PMID:26176548

  3. Fracture Sealing with Microbially-Induced Calcium Carbonate Precipitation: A Field Study.

    PubMed

    Phillips, Adrienne J; Cunningham, Alfred B; Gerlach, Robin; Hiebert, Randy; Hwang, Chiachi; Lomans, Bartholomeus P; Westrich, Joseph; Mantilla, Cesar; Kirksey, Jim; Esposito, Richard; Spangler, Lee

    2016-04-05

    A primary environmental risk from unconventional oil and gas development or carbon sequestration is subsurface fluid leakage in the near wellbore environment. A potential solution to remediate leakage pathways is to promote microbially induced calcium carbonate precipitation (MICP) to plug fractures and reduce permeability in porous materials. The advantage of microbially induced calcium carbonate precipitation (MICP) over cement-based sealants is that the solutions used to promote MICP are aqueous. MICP solutions have low viscosities compared to cement, facilitating fluid transport into the formation. In this study, MICP was promoted in a fractured sandstone layer within the Fayette Sandstone Formation 340.8 m below ground surface using conventional oil field subsurface fluid delivery technologies (packer and bailer). After 24 urea/calcium solution and 6 microbial (Sporosarcina pasteurii) suspension injections, the injectivity was decreased (flow rate decreased from 1.9 to 0.47 L/min) and a reduction in the in-well pressure falloff (>30% before and 7% after treatment) was observed. In addition, during refracturing an increase in the fracture extension pressure was measured as compared to before MICP treatment. This study suggests MICP is a promising tool for sealing subsurface fractures in the near wellbore environment.

  4. Klebsiella pneumoniae Siderophores Induce Inflammation, Bacterial Dissemination, and HIF-1α Stabilization during Pneumonia

    PubMed Central

    Holden, Victoria I.; Breen, Paul; Houle, Sébastien; Dozois, Charles M.

    2016-01-01

    ABSTRACT Klebsiella pneumoniae is a Gram-negative pathogen responsible for a wide range of infections, including pneumonia and bacteremia, and is rapidly acquiring antibiotic resistance. K. pneumoniae requires secretion of siderophores, low-molecular-weight, high-affinity iron chelators, for bacterial replication and full virulence. The specific combination of siderophores secreted by K. pneumoniae during infection can impact tissue localization, systemic dissemination, and host survival. However, the effect of these potent iron chelators on the host during infection is unknown. In vitro, siderophores deplete epithelial cell iron, induce cytokine secretion, and activate the master transcription factor hypoxia inducible factor-1α (HIF-1α) protein that controls vascular permeability and inflammatory gene expression. Therefore, we hypothesized that siderophore secretion by K. pneumoniae directly contributes to inflammation and bacterial dissemination during pneumonia. To examine the effects of siderophore secretion independently of bacterial growth, we performed infections with tonB mutants that persist in vivo but are deficient in siderophore import. Using a murine model of pneumonia, we found that siderophore secretion by K. pneumoniae induces the secretion of interleukin-6 (IL-6), CXCL1, and CXCL2, as well as bacterial dissemination to the spleen, compared to siderophore-negative mutants at an equivalent bacterial number. Furthermore, we determined that siderophore-secreting K. pneumoniae stabilized HIF-1α in vivo and that bacterial dissemination to the spleen required alveolar epithelial HIF-1α. Our results indicate that siderophores act directly on the host to induce inflammatory cytokines and bacterial dissemination and that HIF-1α is a susceptibility factor for bacterial invasion during pneumonia. PMID:27624128

  5. Induced precipitation recycling (IPR) strategy to increase forest growth and regional rainfall

    NASA Astrophysics Data System (ADS)

    Layton, K. M.; Ellison, D.

    2013-12-01

    This presentation describes a project designed to capitalize on observed natural interactions between forest cover and the hydrologic cycle in order to increase available water supplies in arid regions, and to purify degraded water resources. An approach is presented to transition observed precipitation recycling effects into practical applications. Higher regional precipitation can be induced by promoting favorable conditions through afforestation and the irrigation of afforested land (IPR). Waste-water streams processed by the forest can increase local precipitation through the by-product evapotranspiration (ET). The proposed project illustrates how increased runoff from induced precipitation can help mitigate chronic regional water shortages in Southern California, using available degraded water resources. Each day, several hundred million gallons of treated sewage and excess storm water from the Los Angeles basin are channeled to the ocean for disposal. A portion of this can irrigate afforested land, initiating the IPR process. The afforested site likewise produces additional beneficial ecosystem services including nutrient management (of the sewage stream), carbon sequestration (from new growth), cooling of urban 'heat islands', and flood control. Research will explore interactions between ET plumes and local geography to aid the selection of afforestation sites and ensure increased precipitation over land, supporting the regional water supply. The IPR project is designed to manage risk and complexity through phased implementation. While no unproven technologies are used, there are uncertainties in applying theories from scientific research. During the 'pilot phase', initial afforestation site(s) will support research to examine the interactions of irrigated forest cover and IPR. As a proof of concept, this will develop the analytical basis for large-scale expansion. Once the theoretical foundation has been established, the project can expand to more irrigated

  6. Deformation twinning induced decomposition of lamellar LPSO structure and its re-precipitation in an Mg-Zn-Y alloy

    PubMed Central

    Shao, X. H.; Zheng, S. J.; Chen, D.; Jin, Q. Q.; Peng, Z. Z.; Ma, X. L.

    2016-01-01

    The high hardness or yield strength of an alloy is known to benefit from the presence of small-scale precipitation, whose hardening effect is extensively applied in various engineering materials. Stability of the precipitates is of critical importance in maintaining the high performance of a material under mechanical loading. The long period stacking ordered (LPSO) structures play an important role in tuning the mechanical properties of an Mg-alloy. Here, we report deformation twinning induces decomposition of lamellar LPSO structures and their re-precipitation in an Mg-Zn-Y alloy. Using atomic resolution scanning transmission electron microscopy (STEM), we directly illustrate that the misfit dislocations at the interface between the lamellar LPSO structure and the deformation twin is corresponding to the decomposition and re-precipitation of LPSO structure, owing to dislocation effects on redistribution of Zn/Y atoms. This finding demonstrates that deformation twinning could destabilize complex precipitates. An occurrence of decomposition and re-precipitation, leading to a variant spatial distribution of the precipitates under plastic loading, may significantly affect the precipitation strengthening. PMID:27435638

  7. Deformation twinning induced decomposition of lamellar LPSO structure and its re-precipitation in an Mg-Zn-Y alloy

    NASA Astrophysics Data System (ADS)

    Shao, X. H.; Zheng, S. J.; Chen, D.; Jin, Q. Q.; Peng, Z. Z.; Ma, X. L.

    2016-07-01

    The high hardness or yield strength of an alloy is known to benefit from the presence of small-scale precipitation, whose hardening effect is extensively applied in various engineering materials. Stability of the precipitates is of critical importance in maintaining the high performance of a material under mechanical loading. The long period stacking ordered (LPSO) structures play an important role in tuning the mechanical properties of an Mg-alloy. Here, we report deformation twinning induces decomposition of lamellar LPSO structures and their re-precipitation in an Mg-Zn-Y alloy. Using atomic resolution scanning transmission electron microscopy (STEM), we directly illustrate that the misfit dislocations at the interface between the lamellar LPSO structure and the deformation twin is corresponding to the decomposition and re-precipitation of LPSO structure, owing to dislocation effects on redistribution of Zn/Y atoms. This finding demonstrates that deformation twinning could destabilize complex precipitates. An occurrence of decomposition and re-precipitation, leading to a variant spatial distribution of the precipitates under plastic loading, may significantly affect the precipitation strengthening.

  8. Wind induced errors on solid precipitation measurements: an evaluation using time-dependent turbulence simulations

    NASA Astrophysics Data System (ADS)

    Colli, Matteo; Lanza, Luca Giovanni; Rasmussen, Roy; Mireille Thériault, Julie

    2014-05-01

    Among the different environmental sources of error for ground based solid precipitation measurements, wind is the main responsible for a large reduction of the catching performance. This is due to the aero-dynamic response of the gauge that affects the originally undisturbed airflow causing the deformation of the snowflakes trajectories. The application of composite gauge/wind shield measuring configurations allows the improvements of the collection efficiency (CE) at low wind speeds (Uw) but the performance achievable under severe airflow velocities and the role of turbulence still have to be explained. This work is aimed to assess the wind induced errors of a Geonor T200B vibrating wires gauge equipped with a single Alter shield. This is a common measuring system for solid precipitation, which constitutes of the R3 reference system in the ongoing WMO Solid Precipitation InterComparison Experiment (SPICE). The analysis is carried out by adopting advanced Computational Fluid Dynamics (CFD) tools for the numerical simulation of the turbulent airflow realized in the proximity of the catching section of the gauge. The airflow patterns were computed by running both time-dependent (Large Eddies Simulation) and time-independent (Reynolds Averaged Navier-Stokes) simulations. on the Yellowstone high performance computing system of the National Center for Atmospheric Research. The evaluation of CE under different Uw conditions was obtained by running a Lagrangian model for the calculation of the snowflakes trajectories building on the simulated airflow patterns. Particular attention has been paid to the sensitivity of the trajectories to different snow particles sizes and water content (corresponding to dry and wet snow). The results will be illustrated in comparative form between the different methodologies adopted and the existing infield CE evaluations based on double shield reference gauges.

  9. Observation of Long Ionospheric Recoveries from Lightning-induced Electron Precipitation Events

    NASA Astrophysics Data System (ADS)

    Mohammadpour Salut, M.; Cohen, M.

    2015-12-01

    Lightning strokes induces lower ionospheric nighttime disturbances which can be detected through Very Low Frequency (VLF) remote sensing via at least two means: (1) direct heating and ionization, known as an Early event, and (2) triggered precipitation of energetic electrons from the radiation belts, known as Lightning-induced Electron Precipitation (LEP). For each, the ionospheric recover time is typically a few minutes or less. A small class of Early events have been identified as having unusually long ionospheric recoveries (10s of minutes), with the underlying mechanism still in question. Our study shows for the first time that some LEP events also demonstrate unusually long recovery. The VLF events were detected by visual inspection of the recorded data in both the North-South and East-West magnetic fields. Data from the National Lightning Detection Network (NLDN) are used to determine the location and peak current of the lightning responsible for each lightning-associated VLF perturbation. LEP or Early VLF events are determined by measuring the time delay between the causative lightning discharges and the onset of all lightning-associated perturbations. LEP events typically possess an onset delay greater than ~ 200 msec following the causative lightning discharges, while the onset of Early VLF events is time-aligned (<20 msec) with the lightning return stroke. Nonducted LEP events are distinguished from ducted events based on the location of the causative lightning relative to the precipitation region. From 15 March to 20 April and 15 October to 15 November 2011, a total of 385 LEP events observed at Indiana, Montana, Colorado and Oklahoma VLF sites, on the NAA, NLK and NML transmitter signals. 46 of these events exhibited a long recovery. It has been found that the occurrence rate of ducted long recovery LEP events is higher than nonducted. Of the 46 long recovery LEP events, 33 events were induced by ducted whistlers, and 13 events were associated with

  10. Search for wave-induced particle precipitation from lightning and transmitter sources. Master's thesis

    SciTech Connect

    Lundberg, J.E.

    1988-01-01

    Wave-induced particle precipitation is introduced and examined for whistlers whose sources are within the plasmapause. The possible correlation between lightning strokes that carry positive charge to the ground and the observed Trimpi events is discussed, sudden phase and/or amplitude shifts of a received VLF signal with gradual return to predisturbed values. The thunderstorm charging mechanisms that lead to the observed charge distribution and the advection of the positively charged cirrus anvil away from the body of the thunderstorm are briefly examined. The comparative current strengths and the relative frequency of positive and negative strokes is studied for different types of thunderstorms. The magnetospheric ducting of the lightning-generated whistler wave and the interaction with trapped electrons is examined. The detectable effects the precipitating electrons have on the ionosphere is introduced. Included are testing and design of the x-ray detector and balloon-launch considerations. The problems encountered during the x-ray-detector's balloon flights are examined. The riometer and x-ray-detector data-analysis methods are mentioned. The results were negative for the data analyzed, but the limiting factors severely restricted the usable data. Possible experimental methods are mentioned.

  11. A revised model for microbially induced calcite precipitation: Improvements and new insights based on recent experiments

    NASA Astrophysics Data System (ADS)

    Hommel, Johannes; Lauchnor, Ellen; Phillips, Adrienne; Gerlach, Robin; Cunningham, Alfred B.; Helmig, Rainer; Ebigbo, Anozie; Class, Holger

    2015-05-01

    The model for microbially induced calcite precipitation (MICP) published by Ebigbo et al. (2012) has been improved based on new insights obtained from experiments and model calibration. The challenge in constructing a predictive model for permeability reduction in the underground with MICP is the quantification of the complex interaction between flow, transport, biofilm growth, and reaction kinetics. New data from Lauchnor et al. (2015) on whole-cell ureolysis kinetics from batch experiments were incorporated into the model, which has allowed for a more precise quantification of the relevant parameters as well as a simplification of the reaction kinetics in the equations of the model. Further, the model has been calibrated objectively by inverse modeling using quasi-1D column experiments and a radial flow experiment. From the postprocessing of the inverse modeling, a comprehensive sensitivity analysis has been performed with focus on the model input parameters that were fitted in the course of the model calibration. It reveals that calcite precipitation and concentrations of NH4+ and Ca2+ are particularly sensitive to parameters associated with the ureolysis rate and the attachment behavior of biomass. Based on the determined sensitivities and the ranges of values for the estimated parameters in the inversion, it is possible to identify focal areas where further research can have a high impact toward improving the understanding and engineering of MICP.

  12. Spectral induced polarization signatures of hydroxide adsorption and mineral precipitation in porous media

    SciTech Connect

    Chi Zhang; Lee Slater; George Redden; Yoshiko Fujita; Timothy Johnson; Don Fox

    2012-04-01

    The spectral induced polarization (SIP) technique is a promising approach for delineating subsurface physical and chemical property changes in a minimally invasive manner. We investigated spatiotemporal variations in complex conductivity during evolution of urea hydrolysis and calcite precipitation reaction fronts within a silica gel column. The real and imaginary parts of complex conductivity were shown to be sensitive to changes in both solution chemistry and calcium carbonate precipitation. Distinct changes in imaginary conductivity coincided with increased hydroxide ion concentration during urea hydrolysis. In a separate experiment focused on the effect of hydroxide concentration on interfacial polarization of silica gel and well-sorted sand, we found a strong dependence of the polarization response on pH changes of the solution. We propose a conceptual model describing hydroxide ion adsorption behavior in silica gel and its control on interfacial polarizability. Our results demonstrate the utility of SIP for non-invasive monitoring of reaction fronts, and indicate its potential for quantifying geochemical processes that control the polarization responses of porous media at larger spatial scales in the natural environment.

  13. Evidence of Urban-Induced Precipitation Variability in Arid Climate Regimes

    NASA Technical Reports Server (NTRS)

    Shepherd, J. Marshall

    2005-01-01

    Water is essential to life in the Earth system. The water cycle components that sustain life are becoming more scarce and polluted. The most recent (1999-2004) drought experienced in the southwestern United States is the seventh worst in the approximately 500-year proxy tree-ring record. As a result, many regions contemplated drought emergencies in which severe water restrictions are implemented. Though larger weather and climate processes likely control drought processes, there is increasing evidence that anthropogenic or human-related activities can significantly alter precipitation processes. Urbanization is an example of anthropogenic forcing. Recent studies continue to provide evidence that urban environments can modify or induce precipitation under a specific set of conditions. Arid and semi-arid regions of the southwestern United States and other parts of the world are rapidly developing and placing greater demands on the environmental system. In the past fifty years, Phoenix has expanded from a predominantly agricultural center to an urbanized region with extent 700 percent larger than its size in the middle of the twentieth century. Riyadh's population grew from about a half million people in 1972 to almost two million by 2000. Saudi Arabia experienced urbanization later than many other countries; in the early 1970s its urban-rural ratio was still about 1:3. By 1990 the ratio had reversed to about 3:l. In the mid-1970s Riyadh's population was increasing by about 10 percent a year. Irrigation also significantly increased between 1972 and 1990 southeast of Riyadh. The study employs a 108-year precipitation historical data record, global climate observing network observations and satellite data to identify possible anomalies in rainfall in and around two major arid urban areas, Phoenix, Arizona and Riyadh, Saudi Arabia. It provides statistically sound evidence that rainfall distribution and magnitude is statistically different in post-urban than in pre

  14. Spatiotemporal Structure of Tropical Moisture Exports and their Precursors associated with High Precipitation induced Floods over the Continental United States

    NASA Astrophysics Data System (ADS)

    Lu, M.; Lall, U.

    2014-12-01

    Nonstationarity of flood risk has emerged as an important issue and progress in addressing this concern can only come from an improved understanding of the associated climate dynamics. An understanding of the dynamical mechanisms and statistics associated with the frequency and structure of heavy precipitation induced floods events can aid exploration of the key sources of uncertainties that challenge extreme hydrometerological forecasts, and improve reliability of streamflow forecasts for real-time applications. Although the climate mechanisms governing precipitation vary by location, extreme precipitation events in the mid-latitudes are typically associated with anomalous atmospheric moisture from warmer tropical or subtropical oceanic areas. Tropical moisture exports (TMEs) to the Northern Hemispheric extratropics are an important feature of the general circulation of the atmosphere and link tropical moisture sources with extratropical precipitation and occasionally with explosive cyclogenesis. TMEs, contributing to the global climatology precipitation and its extremes, are closely related to flood events, especially in the midlatitudes. Here, a statistically and physically based framework is put forward that investigates the relationship between TMEs, and Extreme Precipitation and Floods over the continental United States, and relates the spatial flood incidence across the regions to the persistence and spatiotemporal structure of these tracks. The origins and pathways of moist and warm tropical air masses, which are the fuel for the heavy precipitation events and rapid cyclogenesis in the extratropics, are examined. The clustered TME tracks provide a critical source of identify different moisture sources and climate dynamics, which governs and drives the movements of water vapor to the flooded areas, together with an atmospheric circulation pattern that leads to persistent multi-day convergence and precipitation in those regions. The genesis location of TME

  15. Photodynamic therapy induces an immune response against a bacterial pathogen

    PubMed Central

    Huang, Ying-Ying; Tanaka, Masamitsu; Vecchio, Daniela; Garcia-Diaz, Maria; Chang, Julie; Morimoto, Yuji; Hamblin, Michael R

    2012-01-01

    Photodynamic therapy (PDT) employs the triple combination of photosensitizers, visible light and ambient oxygen. When PDT is used for cancer, it has been observed that both arms of the host immune system (innate and adaptive) are activated. When PDT is used for infectious disease, however, it has been assumed that the direct antimicrobial PDT effect dominates. Murine arthritis caused by methicillin-resistant Staphylococcus aureus in the knee failed to respond to PDT with intravenously injected Photofrin®. PDT with intra-articular Photofrin produced a biphasic dose response that killed bacteria without destroying host neutrophils. Methylene blue was the optimum photosensitizer to kill bacteria while preserving neutrophils. We used bioluminescence imaging to noninvasively monitor murine bacterial arthritis and found that PDT with intra-articular methylene blue was not only effective, but when used before infection, could protect the mice against a subsequent bacterial challenge. The data emphasize the importance of considering the host immune response in PDT for infectious disease. PMID:22882222

  16. Measurement of precipitation induced FUV emission and Geocoronal Lyman Alpha from the IMI mission

    NASA Technical Reports Server (NTRS)

    Mende, Stephen B.; Fuselier, S. A.; Rairden, R. L.

    1995-01-01

    This final report describes the activities of the Lockheed Martin Palo Alto Research Laboratory in studying the measurement of ion and electron precipitation induced Far Ultra-Violet (FUV) emissions and Geocoronal Lyman Alpha for the NASA Inner Magnetospheric Imager (IMI) mission. this study examined promising techniques that may allow combining several FUV instruments that would separately measure proton aurora, electron aurora, and geocoronal Lyman alpha into a single instrument operated on a spinning spacecraft. The study consisted of two parts. First, the geocoronal Lyman alpha, proton aurora, and electron aurora emissions were modeled to determine instrument requirements. Second, several promising techniques were investigated to determine if they were suitable for use in an IMI-type mission. Among the techniques investigated were the Hydrogen gas cell for eliminating cold geocoronal Lyman alpha emissions, and a coded aperture spectrometer with sufficient resolution to separate Doppler shifted Lyman alpha components.

  17. Isoniazid-induced cell death is precipitated by underlying mitochondrial complex I dysfunction in mouse hepatocytes.

    PubMed

    Lee, Kang Kwang; Fujimoto, Kazunori; Zhang, Carmen; Schwall, Christine T; Alder, Nathan N; Pinkert, Carl A; Krueger, Winfried; Rasmussen, Theodore; Boelsterli, Urs A

    2013-12-01

    Isoniazid (INH) is an antituberculosis drug that has been associated with idiosyncratic liver injury in susceptible patients. The underlying mechanisms are still unclear, but there is growing evidence that INH and/or its major metabolite, hydrazine, may interfere with mitochondrial function. However, hepatic mitochondria have a large reserve capacity, and minor disruption of energy homeostasis does not necessarily induce cell death. We explored whether pharmacologic or genetic impairment of mitochondrial complex I may amplify mitochondrial dysfunction and precipitate INH-induced hepatocellular injury. We found that INH (≤ 3000 μM) did not induce cell injury in cultured mouse hepatocytes, although it decreased hepatocellular respiration and ATP levels in a concentration-dependent fashion. However, coexposure of hepatocytes to INH and nontoxic concentrations of the complex I inhibitors rotenone (3 μM) or piericidin A (30 nM) resulted in massive ATP depletion and cell death. Although both rotenone and piericidin A increased MitoSox-reactive fluorescence, Mito-TEMPO or N-acetylcysteine did not attenuate the extent of cytotoxicity. However, preincubation of cells with the acylamidase inhibitor bis-p-nitrophenol phosphate provided protection from hepatocyte injury induced by rotenone/INH (but not rotenone/hydrazine), suggesting that hydrazine was the cell-damaging species. Indeed, we found that hydrazine directly inhibited the activity of solubilized complex II. Hepatocytes isolated from mutant Ndufs4(+/-) mice, although featuring moderately lower protein expression levels of this complex I subunit in liver mitochondria, exhibited unchanged hepatic complex I activity and were therefore not sensitized to INH. These data indicate that underlying inhibition of complex I, which alone is not acutely toxic, can trigger INH-induced hepatocellular injury.

  18. Bacterial persistence induced by salicylate via reactive oxygen species

    PubMed Central

    Wang, Tiebin; El Meouche, Imane; Dunlop, Mary J.

    2017-01-01

    Persisters are phenotypic variants of regular cells that exist in a dormant state with low metabolic activity, allowing them to exhibit high tolerance to antibiotics. Despite increasing recognition of their role in chronic and recalcitrant infections, the mechanisms that induce persister formation are not fully understood. In this study, we find that salicylate can induce persister formation in Escherichia coli via generation of reactive oxygen species (ROS). Salicylate-induced ROS cause a decrease in the membrane potential, reduce metabolism and lead to an increase in persistence. These effects can be recovered by culturing cells in the presence of a ROS quencher or in an anaerobic environment. Our findings reveal that salicylate-induced oxidative stress can lead to persistence, suggesting that ROS, and their subsequent impact on membrane potential and metabolism, may play a broad role in persister formation. PMID:28281556

  19. Rotation-Induced Polymorphic Transitions in Bacterial Flagella

    NASA Astrophysics Data System (ADS)

    Vogel, Reinhard; Stark, Holger

    2013-04-01

    Bacteria propel themselves with the help of rotating helical flagella. They change their swimming direction during tumbling events in order to increase, for example, their supply of nutrients (chemotaxis). During tumbling a bacterial flagellum assumes different polymorphic states. Based on a continuum model for the motor-flagellum system, we demonstrate that a changing motor torque can initiate these polymorphic transformations. In particular, we investigate the run-and-stop tumble strategy of Rhodobacter sphaeroides which uses a coiled-to-normal transition in its single flagellum. We also show that torque reversal in single-flagellated Escherichia coli generates a normal-to-curly I transition as observed for tumbling E. coli that swim with a bundle of several flagella.

  20. Characterization of Chemically-Induced Bacterial Ghosts (BGs) Using Sodium Hydroxide-Induced Vibrio parahaemolyticus Ghosts (VPGs)

    PubMed Central

    Park, Hyun Jung; Oh, Sung; Vinod, Nagarajan; Ji, Seongmi; Noh, Han Byul; Koo, Jung Mo; Lee, Su Hyeong; Kim, Sei Chang; Lee, Ki-Sung; Choi, Chang Won

    2016-01-01

    Acellular bacterial ghosts (BGs) are empty non-living bacterial cell envelopes, commonly generated by controlled expression of the cloned lysis gene E of bacteriophage PhiX174. In this study, Vibrio parahaemolyticus ghosts (VPGs) were generated by chemically-induced lysis and the method is based on minimum inhibitory concentration (MIC) of sodium hydroxide (NaOH), acetic acid, boric acid, citric acid, maleic acid, hydrochloric acid, and sulfuric acid. The MIC values of the respective chemicals were 3.125, 6.25, <50.0, 25.0, 6.25, 1.56, and 0.781 mg/mL. Except for boric acid, the lysis efficiency reached more than 99.99% at 5 min after treatment of all chemicals. Among those chemicals, NaOH-induced VPGs appeared completely DNA-free, which was confirmed by quantitative real-time PCR. Besides, lipopolysaccharides (LPS) extracted from the NaOH-induced VPGs showed no distinctive band on SDS-PAGE gel after silver staining. On the other hand, LPS extracted from wild-type bacterial cells, as well as the organic acids-induced VPGs showed triple major bands and LPS extracted from the inorganic acids-induced VPGs showed double bands. It suggests that some surface structures in LPS of the NaOH-induced VPGs may be lost, weakened, or modified by the MIC of NaOH. Nevertheless, Limulus amoebocyte lysate assay revealed that there is no significant difference in endotoxic activity between the NaOH-induced VPGs and wild-type bacterial cells. Macrophages exposed to the NaOH-induced VPGs at 0.5 × 106 CFU/mL showed cell viability of 97.9%, however, the MIC of NaOH did not reduce the cytotoxic effect of wild-type bacterial cells. Like Escherichia coli LPS, the NaOH-induced VPGs are an excellent activator of pro-inflammatory cytokines (IL-1β and iNOS), anti-inflammatory cytokine (IL-10), and dual activities (IL-6) in the stimulated macrophage cells. On the other hand, the induction of TNF-α mRNA was remarkable in the macrophages exposed with wild-type cells. Scanning electron

  1. Functionalization of fabrics with PANI/CuO nanoparticles by precipitation route for anti-bacterial applications

    NASA Astrophysics Data System (ADS)

    Thampi, V. V. Anusha; Thanka Rajan, S.; Anupriya, K.; Subramanian, B.

    2015-01-01

    The present work aims at developing copper oxide nanocrystals immobilized onto the fabrics for the improvement of antimicrobial activity. The CuO nanocrytstals were deposited onto woven fabrics and non-woven fabrics through chemical precipitation route. The samples were characterized by XRD, Raman spectroscopy, FE-SEM, and TEM. The presence of CuO on the surface of the fabrics was confirmed by EDAX. The CuO nanoparticles were found to have grown to a size of 50 nm with a monoclinic structure. The antibacterial activities were assessed for the coated CuO samples by the agar diffusion plate method followed by FE-SEM. To promote the slow release of Cu ions into the medium from the fabric matrix, the synthesized nanoparticles were immobilized in polyaniline polymer matrix before being coated onto the fabric samples, and the results are discussed.

  2. Alteration of epithelial cell lysosomal integrity induced by bacterial cholesterol‐dependent cytolysins

    PubMed Central

    Malet, Julien Karim

    2016-01-01

    Abstract Bacterial pathogens can interfere during infection with host cell organelles, such as mitochondria, the endoplasmic reticulum‐Golgi system or nuclei. As important cellular functions are often compartmentalized in these organelles, their targeting allows pathogens to manipulate key host functions during infection. Here, we identify lysosomes as a new class of organelles targeted by the pathogenic bacterium Listeria monocytogenes. We demonstrate that extracellular Listeria, via secretion of the pore‐forming toxin listeriolysin O, alters lysosomal integrity in epithelial cells but not in macrophages. Listeriolysin O induces lysosomal membrane permeabilization and release of lysosomal content, such as cathepsins proteases, which remain transiently active in the host cytosol. We furthermore show that other bacterial pore‐forming toxins, such as perfringolysin O and pneumolysin, also induce lysosomes alteration. Together, our data unveil a novel activity of bacterial cholesterol‐dependent cytolysins. PMID:27739224

  3. Seasonal, latitudinal and diurnal distributions of whistler-induced electron precipitation events

    SciTech Connect

    Carpenter, D.L.; Inan, U.S. )

    1987-04-01

    The seasonal, latitudinal, and diurnal distributions of whistler-induced electron precipitation events, detected as subionospheric signal perturbations (Trimpi events), have been studied by means of data sets acquired in 1982-1983 at Palmer and Siple stations, Antarctica. The data sets, substantially larger than any previously examined, confirm previous indications of a broad ({approximately} 4 hour) maximum in hourly event occurrence rates. The peak was centered {approximately} 1-2 hours after local midnight at Palmer for the roughly north-south Argentina Omega 12.9-kHz path, but was shifted several hours later for the 23.4-kHz NPM path, which has a westerly arrival bearing at Palmer. The previously reported seasonal variation, with peaks at the equinoxes, was confirmed; activity persisted in the austral winter, particularly following a magnetic storm, but in general occurred on fewer days and during shorter daily periods. Comparisons of occurrence data at Siple (L {approx equal} 4.3) and Palmer (L {approx equal}2.4) for particular signal sources showed the number of days of activity to be larger at Palmer by a factor of {approximately} 2 or more. Comparisons of five months of simultaneous Palmer and Siple receptions of 21.4-kHz NSS signals on north-south paths suggest that most of the events observed at Siple occurred as the result of ionospheric perturbations relatively close to the L shell of Palmer, that is, in the range L = 2-3. This result is consistent with the expected variation with latitude of the energy of electrons precipitated due to equatorial gyroresonance at typical whistler frequencies.

  4. Complete genome sequence of Lysinibacillus sphaericus LMG 22257, a strain with ureolytic activity inducing calcium carbonate precipitation.

    PubMed

    Yan, Wenkai; Xiao, Xiang; Zhang, Yu

    2017-03-20

    Microbiologically induced calcium carbonate precipitation shows the potential for use in bioremediation and construction consolidation, but the efficiency of this process must be improved. Lysinibacillus sphaericus LMG 22257 is a gram-positive ureolytic strain that has recently been applied for consolidating construction by mediating calcium carbonate precipitation. The complete genome sequence of L. sphaericus LMG 22257 is 3,436,578 base pairs with a GC content of 38.99%. The urea degradation pathway and genes related to extracellular polymeric substance biosynthesis were also identified. The strain can tolerate high alkalinity (pH up to 10) and high urea concentration (up to 3M). These findings provide insights into the microbiologically induced carbonate precipitation and extend the application of the metabolic potential of L. sphaericus LMG 22257 for bioremediation.

  5. Sensing cytosolic RpsL by macrophages induces lysosomal cell death and termination of bacterial infection.

    PubMed

    Zhu, Wenhan; Tao, Lili; Quick, Marsha L; Joyce, Johanna A; Qu, Jie-Ming; Luo, Zhao-Qing

    2015-03-01

    The intracellular bacterial pathogen Legionella pneumophila provokes strong host responses and has proven to be a valuable model for the discovery of novel immunosurveillance pathways. Our previous work revealed that an environmental isolate of L. pneumophila induces a noncanonical form of cell death, leading to restriction of bacterial replication in primary mouse macrophages. Here we show that such restriction also occurs in infections with wild type clinical isolates. Importantly, we found that a lysine to arginine mutation at residue 88 (K88R) in the ribosome protein RpsL that not only confers bacterial resistance to streptomycin, but more importantly, severely attenuated the induction of host cell death and enabled L. pneumophila to replicate in primary mouse macrophages. Although conferring similar resistance to streptomycin, a K43N mutation in RpsL does not allow productive intracellular bacterial replication. Further analysis indicated that RpsL is capable of effectively inducing macrophage death via a pathway involved in lysosomal membrane permeabilization; the K88R mutant elicits similar responses but is less potent. Moreover, cathepsin B, a lysosomal protease that causes cell death after being released into the cytosol upon the loss of membrane integrity, is required for efficient RpsL-induced macrophage death. Furthermore, despite the critical role of cathepsin B in delaying RpsL-induced cell death, macrophages lacking cathepsin B do not support productive intracellular replication of L. pneumophila harboring wild type RpsL. This suggests the involvement of other yet unidentified components in the restriction of bacterial replication. Our results identified RpsL as a regulator in the interactions between bacteria such as L. pneumophila and primary mouse macrophages by triggering unique cellular pathways that restrict intracellular bacterial replication.

  6. A quantitative model of bacterial mismatch repair as applied to studying induced mutagenesis

    NASA Astrophysics Data System (ADS)

    Belov, O. V.; Chuluunbaatar, O.; Kapralov, M. I.; Sweilam, N. H.

    2013-11-01

    The paper presents a mathematical model of the DNA mismatch repair system in Escherichia coli bacterial cells. The key pathways of this repair mechanism were simulated on the basis of modern experimental data. We have modelled in detail five main pathways of DNA misincorporation removal with different DNA exonucleases. Here we demonstrate an application of the model to problems of radiation-induced mutagenesis.

  7. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    NASA Astrophysics Data System (ADS)

    Yu, L. D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

    2014-05-01

    As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10-20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  8. Rapid identification and discrimination of bacterial strains by laser induced breakdown spectroscopy and neural networks.

    PubMed

    Manzoor, S; Moncayo, S; Navarro-Villoslada, F; Ayala, J A; Izquierdo-Hornillos, R; de Villena, F J Manuel; Caceres, J O

    2014-04-01

    Identification and discrimination of bacterial strains of same species exhibiting resistance to antibiotics using laser induced breakdown spectroscopy (LIBS) and neural networks (NN) algorithm is reported. The method has been applied to identify 40 bacterial strains causing hospital acquired infections (HAI), i.e. Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Salmonella pullurum and Salmonella salamae. The strains analyzed included both isolated from clinical samples and constructed in laboratory that differ in mutations as a result of their resistance to one or more antibiotics. Small changes in the atomic composition of the bacterial strains, as a result of their mutations and genetic variations, were detected by the LIBS-NN methodology and led to their identification and classification. This is of utmost importance because solely identification of bacterial species is not sufficient for disease diagnosis and identification of the actual strain is also required. The proposed method was successfully able to discriminate strains of the same bacterial species. The optimized NN models provided reliable bacterial strain identification with an index of spectral correlation higher than 95% for the samples analyzed, showing the potential and effectiveness of the method to address the safety and social-cost HAI-related issue.

  9. Selective nucleation induced by defect nanostructures: A way to control cobalt disilicide precipitation during ion implantation

    SciTech Connect

    Fortuna, F.; Nguyen, M.-A.; Ruault, M.-O.; Kirk, M. A.; Borodin, V. A.; Ganchenkova, M. G.

    2012-12-15

    In this paper, we show a way to control cobalt disilicide precipitation during Co ion implantation at high temperatures (650 Degree-Sign C) by affecting radiation defects involved in precipitate nucleation and growth. We demonstrate that the relative shares of different precipitate types nucleated by implantation are strongly affected by defect microstructures deliberately created in investigated samples prior to cobalt implantation. Especially interesting is the effect of a dense ensemble of extremely small (1-3 nm) cavities, which promotes the formation of a relatively uniform layer of coherent cobalt disilicide precipitates with a narrow size distribution. In order to better understand the mechanism of the microstructural influence on the precipitate nucleation modes during Co implantation, we investigate the disilicide precipitation using different implantation setups and compare the results with those for cavity-free Si specimens implanted in similar conditions.

  10. STRESS ANNEALING INDUCED DIFFUSE SCATTERING FROM Ni3(Al,Si) PRECIPITATES

    SciTech Connect

    Barabash, Rozaliya; Ice, Gene E; Karapetrova, Evgenia; Zschack, P.

    2012-01-01

    Diffuse scattering caused by L12 type Ni3 (Al,Si) precipitates after stress annealing of Ni-Al-Si alloys is studied. Experimental reciprocal space maps are compared to the theoretical ones. Oscillations of diffuse scattering due to Ni3 (Al,Sc) precipitates are observed. Peculiarities of diffuse scattering in asymptotic region as compared to Huang scattering region are discussed. Coupling between the stress annealing direction and the precipitate shape is demonstrated.

  11. [The long-term therapy of familial hypercholesterolemia with heparin-induced extracorporeal LDL precipitation].

    PubMed

    Roth, R; Köster, W; Wanner, C; Andre, M; Orth, M; Wieland, H; Schollmeyer, P

    1992-07-24

    The long-term tolerance to and effectiveness of heparin-induced extracorporeal LDL precipitation (HELP) in combination with lipid reducing drugs and diet was tested in six patient (5 males, 1 female; mean age 48 +/- 4 years). Follow-up period was over 50 months, in one patient over 24 months, while one man had a sudden cardiac death 57 weeks after starting treatment. The study was divided into three phases. In phase I (24 months) treatment consisted of HELP and conventional lipid-reducing drugs; in phase II (12 months) of lovastatin (80 mg daily) and cholestyramine (12-24 g daily); and phase III (14 months) of HELP, lovastatin and cholestyramine. In phase I it was possible to lower the pre-treatment level of LDL-cholesterol from 306 +/- 18 mg/dl to 173 +/- 13 mg/dl (43.5%). A similar effect (from 307 +/- 21 mg/dl to 155 +/- 17 mg/dl [-49.5%]) was obtained in phase II. The resumption of HELP reduced the pre-treatment LDL concentration to 136 +/- 9 mg/dl (-55.7%). The various treatment regimens were well tolerated. Biochemical data remained unchanged except for iron loss requiring substitution. Thus combined HELP, lovastatin and ion exchange offer for the first time an effective and reliable means in familial hypercholesterolaemia of clearly reducing long-term the mean LDL cholesterol level below the atherosclerosis threshold of 120 mg/dl.

  12. Observations of blocking-induced convergence zones and effects on precipitation in complex terrain

    NASA Astrophysics Data System (ADS)

    Wesley, Douglas A.; Pielke, Roger A.

    Through an extensive set of observations, including standard surface measurements, Doppler radar, routine National Weather Service radiosondes and special Cross-chain Loran Atmospheric Sounding System (CLASS) data, two case studies of wintertime storms on the east slopes of the Rocky Mountains of Colorado are presented (9-10 February 1988 and 30-31 March 1988). The emphases are the effects of blocking-induced convergence zones on snowfall distributions, snow crystal production mechanisms and banded reflectivity structure. As shown by the analysis of a typical Front Range storm, cold air damming can frequently lead to convergence zones and enhanced precipitation east of the mountains. The meso-fronts often form in place just east of the foothills, and are sensitive to the nature of the low-level synoptic easterly flow. For other upslope situations, the convergence zone does not appear as a meso-front, but as a less distinct area of convergence. Measured vertical profiles associated with the blocked surface patterns reveal a distincly layered temperature and wind structure. These soundings, along with surface measurements of wind, moisture and snow crystal types, enable some microphysical interpretation to be made concerning snowfall production in zones of ascent aloft, which are related to frontal surface as well as lifting at the top of the blocking-induced cold pool. Predominance of heavily rimed, dendritic aggregates implies lifting associated with the layered vertical structure in both storms. Bands of enhanced Doppler reflectivity exhibit significant correlation with snowfall intensity. The two case studies demonstrate that distinctly different patterns of blocking and convergence can appear in Colorado Front Range storms, each resulting in a unique snowfall distribution.

  13. Characterization of maize cytochrome P450 monooxygenases induced in response to safeners and bacterial pathogens.

    PubMed

    Persans, M W; Wang, J; Schuler, M A

    2001-02-01

    Plants use a diverse array of cytochrome P450 monooxygenases in their biosynthetic and detoxification pathways. To determine the extent to which various maize P450s are induced in response to chemical inducers, such as naphthalic anhydride (NA), triasulfuron (T), phenobarbital, and bacterial pathogens (Erwinia stuartii, Acidovorax avenae), we have analyzed the response patterns of seven P450 transcripts after treatment of seedlings with these inducers. Each of these P450 transcripts has distinct developmental, tissue-specific, and chemical cues regulating their expression even when they encode P450s within the same biosynthetic pathway. Most notably, the CYP71C1 and CYP71C3 transcripts, encoding P450s in the DIMBOA biosynthetic pathway, are induced to the same level in response to wounding and NA treatment of younger seedlings and differentially in response to NA/T treatment of younger seedlings and NA and NA/T treatment of older seedlings. NA and T induce expression of both CYP92A1 and CYP72A5 transcripts in older seedling shoots, whereas phenobarbital induces CYP92A1 expression in older seedling shoots and highly induces CYP72A5 expression in young and older seedling roots. Expressed sequence tag (EST) 6c06b11 transcripts, encoding an undefined P450 activity, are highly induced in seedling shoots infected with bacterial pathogens.

  14. Characterization of Maize Cytochrome P450 Monooxygenases Induced in Response to Safeners and Bacterial Pathogens1

    PubMed Central

    Persans, Michael W.; Wang, Jian; Schuler, Mary A.

    2001-01-01

    Plants use a diverse array of cytochrome P450 monooxygenases in their biosynthetic and detoxification pathways. To determine the extent to which various maize P450s are induced in response to chemical inducers, such as naphthalic anhydride (NA), triasulfuron (T), phenobarbital, and bacterial pathogens (Erwinia stuartii, Acidovorax avenae), we have analyzed the response patterns of seven P450 transcripts after treatment of seedlings with these inducers. Each of these P450 transcripts has distinct developmental, tissue-specific, and chemical cues regulating their expression even when they encode P450s within the same biosynthetic pathway. Most notably, the CYP71C1 and CYP71C3 transcripts, encoding P450s in the DIMBOA biosynthetic pathway, are induced to the same level in response to wounding and NA treatment of younger seedlings and differentially in response to NA/T treatment of younger seedlings and NA and NA/T treatment of older seedlings. NA and T induce expression of both CYP92A1 and CYP72A5 transcripts in older seedling shoots, whereas phenobarbital induces CYP92A1 expression in older seedling shoots and highly induces CYP72A5 expression in young and older seedling roots. Expressed sequence tag (EST) 6c06b11 transcripts, encoding an undefined P450 activity, are highly induced in seedling shoots infected with bacterial pathogens. PMID:11161067

  15. Calcium-induced precipitate formation in brain mitochondria: composition, calcium capacity, and retention.

    PubMed

    Kristian, Tibor; Pivovarova, Natalia B; Fiskum, Gary; Andrews, S Brian

    2007-08-01

    Both isolated brain mitochondria and mitochondria in intact neurons are capable of accumulating large amounts of calcium, which leads to formation in the matrix of calcium- and phosphorus-rich precipitates, the chemical composition of which is largely unknown. Here, we have used inhibitors of the mitochondrial permeability transition (MPT) to determine how the amount and rate of mitochondrial calcium uptake relate to mitochondrial morphology, precipitate composition, and precipitate retention. Using isolated rat brain (RBM) or liver mitochondria (RLM) Ca(2+)-loaded by continuous cation infusion, precipitate composition was measured in situ in parallel with Ca(2+) uptake and mitochondrial swelling. In RBM, the endogenous MPT inhibitors adenosine 5'-diphosphate (ADP) and adenosine 5'-triphosphate (ATP) increased mitochondrial Ca(2+) loading capacity and facilitated formation of precipitates. In the presence of ADP, the Ca/P ratio approached 1.5, while ATP or reduced infusion rates decreased this ratio towards 1.0, indicating that precipitate chemical form varies with the conditions of loading. In both RBM and RLM, the presence of cyclosporine A in addition to ADP increased the Ca(2+) capacity and precipitate Ca/P ratio. Following MPT and/or depolarization, the release of accumulated Ca(2+) is rapid but incomplete; significant residual calcium in the form of precipitates is retained in damaged mitochondria for prolonged periods.

  16. Radiation-induced instability of MnS precipitates and its possible consequences on irradiation-induced stress corrosion cracking of austenitic stainless steels

    SciTech Connect

    Chung, H.M.; Sanecki, J.E.; Garner, F.A.

    1996-12-01

    Irradiation-assisted stress corrosion cracking (IASCC) is a significant materials issue for the light water reactor (LWR) industry and may also pose a problem for fusion power reactors that will use water as coolant. A new metallurgical process is proposed that involves the radiation-induced release into solution of minor impurity elements not usually thought to participate in IASCC. MnS-type precipitates, which contain most of the sulfur in stainless steels, are thought to be unstable under irradiation. First, Mn transmutes strongly to Fe in thermalized neutron spectra. Second, cascade-induced disordering and the inverse Kirkendall effect operating at the incoherent interfaces of MnS precipitates are thought to act as a pump to export Mn from the precipitate into the alloy matrix. Both of these processes will most likely allow sulfur, which is known to exert a deleterious influence on intergranular cracking, to re-enter the matrix. To test this hypothesis, compositions of MnS-type precipitates contained in several unirradiated and irradiated heats of Type 304, 316, and 348 stainless steels (SSs) were analyzed by Auger electron spectroscopy. Evidence is presented that shows a progressive compositional modification of MnS precipitates as exposure to neutrons increases in boiling water reactors. As the fluence increases, the Mn level in MnS decreases, whereas the Fe level increases. The S level also decreases relative to the combined level of Mn and Fe. MnS precipitates were also found to be a reservoir of other deleterious impurities such as F and O which could be also released due to radiation-induced instability of the precipitates.

  17. The Use of Laser-Induced Breakdown Spectroscopy for Distinguishing Between Bacterial Pathogen Species and Strains

    PubMed Central

    Multari, Rosalie A.; Cremers, David A.; Dupre, Joanne M.; Gustafson, John E.

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used in a blind study to successfully differentiate bacterial pathogens, both species and strain. The pathogens used for the study were chosen and prepared by one set of researchers. The LIBS data were collected and analyzed by another set of researchers. The latter researchers had no knowledge of the sample identities other than that (1) the first five of fifteen samples were unique (not replicates) and (2) the remaining ten samples consisted of two replicates of each of the first five samples. Using only chemometric analysis of the LIBS data, the ten replicate bacterial samples were successfully matched to each of the first five samples. The results of this blind study show it is possible to differentiate the bacterial pathogens Escherichia coli, three clonal methicillin-resistant Staphylococcus aureus (MRSA) strains, and one unrelated MRSA strain using LIBS. This is an important finding because it demonstrates that LIBS can be used to determine bacterial pathogen species within a defined sample set and can be used to differentiate between clonal relationships among strains of a single multiple-antibiotic-resistant bacterial species. Such a capability is important for the development of LIBS instruments for use in medical, water, and food safety applications. PMID:20615288

  18. FORWARD AND INVERSE BIO-GEOCHEMICAL MODELING OF MICROBIALLY INDUCED PRECIPITATION IN 0.5M COLUMNAR EXPERIMENTS

    NASA Astrophysics Data System (ADS)

    Barkouki, T. H.; Martinez, B.; Mortensen, B.; Dejong, J.; Weathers, T. S.; Spycher, N.; Ginn, T. R.; Fujita, Y.; Smith, R. W.

    2009-12-01

    Subsurface contamination by metals and radionuclides threatens water supplies and ecosystem health at sites worldwide. One potential solution is immobilization in calcite where mineral precipitation is induced in situ by microbially-mediated ureolysis. Specifically, immobile aerobic biophases (cells or enzymes) mediate the conversion of urea to ammonium and carbonate, raising pH and promoting calcite precipitation. Divalent species such as strontium (including 90Sr, a common radionuclide contaminant) can co-precipitate, resulting in in situ immobilization. In waters that are saturated with respect to calcite, this represents a long-term sequestration mechanism. Calcite precipitation also enables control of mechanical properties of the medium through the cementation of particles thus increasing the shear strength and stiffness, while decreasing the permeability and compressibility. Challenges in application include design of the injectate aqueous chemistry (e.g., calcium, carbonate, urea, pH buffer, microbial nutrients) and selection of injection rates in order to control the timing and rate of calcite precipitation to generate the desired spatial distribution. Modeling ultimately requires incorporation of comprehensive reaction networks into transport simulators for non-uniform flow. To develop and validate the reaction network for use in both contaminant co-precipitation and subsurface structural modification applications, multicomponent biogeochemical modeling (TOUGHREACT v2) was applied in analyses of laboratory batch and column investigations of microbially-mediated calcite precipitation using Sporosarcina pasteurii. Column experiments included continuous and repeat pulse-flows, with cumulative flux equal in both cases. Aqueous chemistry and calcite distribution were monitored, as well as seismic shear waves that correlate to the stiffness of the column and thus to precipitation extent. TOUGHREACT was coupled with the inversion code UCODE to invert on observed

  19. Effects of Exogenous Cholecystokinin Octapeptide on Acquisition of Naloxone Precipitated Withdrawal Induced Conditioned Place Aversion in Rats

    PubMed Central

    Ma, Chunling; Meng, Yanxin; Li, Shujin; Ni, Zhiyu; Cong, Bin

    2012-01-01

    Cholecystokinin octapeptide (CCK-8), a gut-brain peptide, regulates a variety of physiological behavioral processes. Previously, we reported that exogenous CCK-8 attenuated morphine-induced conditioned place preference, but the possible effects of CCK-8 on aversively motivated drug seeking remained unclear. To investigate the effects of endogenous and exogenous CCK on negative components of morphine withdrawal, we evaluated the effects of CCK receptor antagonists and CCK-8 on the naloxone-precipitated withdrawal-induced conditioned place aversion (CPA). The results showed that CCK2 receptor antagonist (LY-288,513, 10 µg, i.c.v.), but not CCK1 receptor antagonist (L-364,718, 10 µg, i.c.v.), inhibited the acquisition of CPA when given prior to naloxone (0.3 mg/kg) administration in morphine-dependent rats. Similarly, CCK-8 (0.1–1 µg, i.c.v.) significantly attenuated naloxone-precipitated withdrawal-induced CPA, and this inhibitory function was blocked by co-injection with L-364,718. Microinjection of L-364,718, LY-288,513 or CCK-8 to saline pretreated rats produced neither a conditioned preference nor aversion, and the induction of CPA by CCK-8 itself after morphine pretreatments was not significant. Our study identifies a different role of CCK1 and CCK2 receptors in negative affective components of morphine abstinence and an inhibitory effect of exogenous CCK-8 on naloxone-precipitated withdrawal-induced CPA via CCK1 receptor. PMID:22848639

  20. Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels

    SciTech Connect

    Chung, H.M.; Garner, F.A.

    1996-10-01

    Irradiation assisted stress corrosion cracking (IASCC) continues to be a significant materials issue for the light water reactor industry and may also pose a problem for fusion power devices that employ water cooling. Although a number of potential mechanisms have been proposed to participate in this phenomenon, at this time it is not clear that any of these candidate mechanisms are sufficient to rationalize the observed failures. A new mechanism is proposed in this paper that involves the radiation-induced release into solution of elements not usually thought to participate in IASCC. It is shown in this paper that MnS precipitates, which contain most of the sulphur in stainless steels, are probably unstable under irradiation. First, the Mn transmutes very strongly to Fe in highly thermalized neutron spectra. Second, the combination of cascade-induced disordering and the inverse-Kirkendall effect operating at the incoherent interfaces of MnS precipitates will probably act as a pump to export Mn from the precipitate surface into the alloy matrix. Both of these processes will most likely allow some of the sulphur to re-enter the alloy matrix. Sulphur is known to exert a deleterious influence on grain boundary cracking. MnS precipitates are also thought to be a reservoir of other deleterious impurities such as fluorine which could be also released due to radiation-induced instability of the precipitates. This possibility has been confirmed by Auger electron spectroscopy of Types 304, 316, and 348 stainless steel specimens sectioned from several BWR components irradiated up to 3.5x10{sup 21} n/cm{sup 2} (E > 1 MeV).

  1. Quantification of precipitation measurement discontinuity induced by wind shields on national gauges

    USGS Publications Warehouse

    Yang, D.; Goodison, B.E.; Metcalfe, J.R.; Louie, P.; Leavesley, G.; Emerson, D.; Hanson, C.L.; Golubev, V.S.; Elomaa, E.; Gunther, T.; Pangburn, T.; Kang, E.; Milkovic, J.

    1999-01-01

    Various combinations of wind shields and national precipitation gauges commonly used in countries of the northern hemisphere have been studied in this paper, using the combined intercomparison data collected at 14 sites during the World Meteorological Organization's (WMO) Solid Precipitation Measurement Intercomparison Project. The results show that wind shields improve gauge catch of precipitation, particularly for snow. Shielded gauges, on average, measure 20-70% more snow than unshielded gauges. Without a doubt, the use of wind shields on precipitation gauges has introduced a significant discontinuity into precipitation records, particularly in cold and windy regions. This discontinuity is not constant and it varies with wind speed; temperature, and precipitation type. Adjustment for this discontinuity is necessary to obtain homogenous precipitation data for climate change and hydrological studies. The relation of the relative catch ratio (RCR, ratio of measurements of shielded gauge to unshielded gauge) versus wind speed and temperature has been developed for Alter and Tretyakov wind shields. Strong linear relations between measurements of shielded gauge and unshielded gauge have also been found for different precipitation types. The linear relation does not fully take into account the varying effect of wind and temperature on gauge catch. Overadjustment by the linear relation may occur at those sites with lower wind speeds, and underadjustment may occur at those stations with higher wind speeds. The RCR technique is anticipated to be more applicable in a wide range of climate conditions. The RCR technique and the linear relation have been tested at selected WMO intercomparison stations, and reasonable agreement between the adjusted amounts and the shielded gauge measurement was obtained at most of the sites. Test application of the developed methodologies to a regional or national network is therefore recommended to further evaluate their applicability in

  2. Pseudospherulitic fibrous calcite from the Quaternary shallow lacustrine carbonates of the Farafra Oasis, Western Desert, Egypt: A primary precipitate with possible bacterial influence

    NASA Astrophysics Data System (ADS)

    Wanas, H. A.

    2012-04-01

    Pseudospherulitic fibrous calcite (PFC) has been found as a major constituent (85-90%) within thin massive limestone beds of the Quaternary mudflat-shallow lacustrine facies association (1.5-2 m thick) that forms part of combined facies associations of the Quaternary clastic-carbonate unit (25-30 m thick) at Bir-Karawein area in the Farafra Oasis, Western Desert, Egypt. The thin massive limestone beds (2-5 cm thick) are devoid of pedogenic features and marine fossils. They form a rhythmic cyclic succession with thin massive mudrocks (5-10 cm thick). The mudflat-shallow lacustrine facies association herein occurs within a depositional sequence of distal alluvial-floodplain (6-12 m thick) and palustrine (1.5-4.5 m thick) facies associations. The PFC is a composed of loosely packed rounded to sub-rounded single low-Mg-calcite crystals (150-250 μm-sized) with intracrystalline fibrous microfabric marked by fibers (150-250 μm long and 10-20 μm wide) radiating from the center of the individual crystals and displaying irregular internal growth with lobate pattern. The PFC crystals show non-planar to highly irregular intercrystalline boundaries. Under SEM, the individual crystal fibers group of PFC form ellipsoid to sub-globular bodies. Each PFC crystal exhibits successive zones of thick non-luminescence and thin brightly orange to dull luminescence. The matrix (10-15%) between the PFC crystals is mainly a honeycomb-like smectite. The PFC is postulated to be a primary precipitate. This concept is reached because the PFC: (i) does not display the criteria of typical Microcodium structures, root-calcification, speleothem structures, calcite spherulites of laminar calcretes, and calcitization of precursor dolomite or aragonite, (ii) possesses homogenous compositional and textural characteristics, and (iii) occurs within limestone beds that lie in between impermeable massive mudrock beds that dampen diagenesis. A role for possible bacterial contribution in crystallization of

  3. The methyltransferase Setdb2 mediates virus-induced susceptibility to bacterial superinfection

    PubMed Central

    Schliehe, Christopher; Swaminanthan, Savitha; Bosnjak, Berislav; Bauer, Lisa; Kandasamy, Richard K.; Griesshammer, Isabel M.; Kosack, Lindsay; Schmitz, Frank; Litvak, Vladimir; Sissons, James; Lercher, Alexander; Bhattacharya, Anannya; Khamina, Kseniya; Trivett, Anna L.; Tessarollo, Lino; Mesteri, Ildiko; Hladik, Anastasiya; Merkler, Doron; Kubicek, Stefan; Knapp, Sylvia; Epstein, Michelle M.; Bergthaler, Andreas

    2014-01-01

    Immune responses are tightly regulated to ensure efficient pathogen clearance while avoiding tissue damage. Here we report that SET domain bifurcated 2 (Setdb2) was the only protein lysine methyltransferase induced during influenza virus infection. Setdb2 expression depended on type-I interferon signaling and it repressed the expression of the neutrophil attractant Cxcl1 and other NF-κB target genes. This coincided with Setdb2 occupancy at the Cxcl1 promoter, which in the absence of Setdb2 displayed reduced H3K9 tri-methylation. Setdb2 hypomorphic gene-trap mice exhibited increased neutrophil infiltration in sterile lung inflammation and were less sensitive to bacterial superinfection upon influenza virus infection. This suggests that a Setdb2-mediated regulatory crosstalk between the type-I interferon and NF-κB pathways represents an important mechanism for virus-induced susceptibility to bacterial superinfection. PMID:25419628

  4. Low-energy plasma immersion ion implantation to induce DNA transfer into bacterial E. coli

    NASA Astrophysics Data System (ADS)

    Sangwijit, K.; Yu, L. D.; Sarapirom, S.; Pitakrattananukool, S.; Anuntalabhochai, S.

    2015-12-01

    Plasma immersion ion implantation (PIII) at low energy was for the first time applied as a novel biotechnology to induce DNA transfer into bacterial cells. Argon or nitrogen PIII at low bias voltages of 2.5, 5 and 10 kV and fluences ranging from 1 × 1012 to 1 × 1017 ions/cm2 treated cells of Escherichia coli (E. coli). Subsequently, DNA transfer was operated by mixing the PIII-treated cells with DNA. Successes in PIII-induced DNA transfer were demonstrated by marker gene expressions. The induction of DNA transfer was ion-energy, fluence and DNA-size dependent. The DNA transferred in the cells was confirmed functioning. Mechanisms of the PIII-induced DNA transfer were investigated and discussed in terms of the E. coli cell envelope anatomy. Compared with conventional ion-beam-induced DNA transfer, PIII-induced DNA transfer was simpler with lower cost but higher efficiency.

  5. Precipitant induced porosity augmentation of polystyrene preserves the chondrogenicity of human chondrocytes.

    PubMed

    Joergensen, Natasja L; Foldager, Casper B; Le, Dang Q S; Lind, Martin; Lysdahl, Helle

    2016-12-01

    Cells constantly sense and receive chemical and physical signals from neighboring cells, interstitial fluid, and extracellular matrix, which they integrate and translate into intracellular responses. Thus, the nature of the surface on which cells are cultured in vitro plays an important role for cell adhesion, proliferation, and differentiation. Autologs chondrocyte implantation is considered the treatment of choice for larger cartilage defects in the knee. To obtain a sufficient number of chondrocytes for implantation multiple passaging is often needed, which raises concerns about the changes in the chondrogenic phenotype. In the present study, we analyzed the effect at cellular and molecular level of precipitant induced porosity augmentation (PIPA) of polystyrene surfaces on proliferation and differentiation of human chondrocytes. Human chondrocytes were isolated from healthy patients undergoing anterior cruciate ligament reconstruction and cultured on PIPA modified polystyrene surfaces. Microscopical analysis revealed topographically arranged porosity with micron pores and nanometer pits. Chondrocytes cultured on PIPA surfaces revealed no difference in cell viability and proliferation, but gene- and protein expressions of collagen type II were pronounced in the first passage of chondrocytes when compared to chondrocytes cultured on control surfaces. Additionally, an analysis of 40 kinases revealed that chondrocytes expanded on PIPA caused upregulated PI3K/mTOR pathway activation and inhibition of mTORC1 resulted in reduced sGAG synthesis. These findings indicate that PIPA modified polystyrene preserved the chondrogenicity of expanded human chondrocytes at gene and protein levels, which clinically may be attractive for the next generation of cell-culture surfaces for ex vivo cell growth. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3073-3081, 2016.

  6. Rapid, Room-Temperature Formation of Crystalline Calcium Molybdate Phosphor Microparticles via Peptide-Induced Precipitation

    DTIC Science & Technology

    2006-01-01

    observed that most of the precipi- tate was lost through dissolution . In a subsequent experiment under similar precipitation conditions, the precipitate was...aspartate, glutamate) in addition to the C-terminal carboxylate group. Li et al. have previously reported that calcite -binding pep- tides, identified...Philips PW 1800, PANalytical Almelo, The Netherlands) were conducted with Cu Ka radiation at a scan rate of 0.6° min–1. TG analyses were conducted with

  7. Resolution of chronic bacterial-induced prostatic inflammation reverses established fibrosis

    PubMed Central

    Wong, Letitia; Hutson, Paul R.; Bushman, Wade

    2014-01-01

    Background Prostatic inflammation has been suggested to contribute to the etiology of lower urinary tract symptoms by inducing fibrosis. We previously used a well-characterized mouse model of bacterial-induced prostate inflammation to demonstrate that chronic prostatic inflammation induces collagen deposition. Here, we examined stability of the newly synthesized collagen in bacterial-induced prostatic inflammation and the reversibility of fibrosis after resolution of infection and inflammation. Methods Uropathogenic E. coli 1677 was instilled transurethrally into adult C3H/HeOuJ male mice to induce chronic prostatic inflammation. Collagen was labeled by 3H-proline administration for 28 days post-inoculation and 3H-hydroxyproline incorporation measured to determine stability of the newly synthesized collagen. Inflammation score was graded using a previously established system and total collagen content was measured by picrosirius red staining quantitation and hydroxyproline content. Resolution of inflammation and reversal of collagen deposition was assessed after treatment with antibiotic enrofloxacin for two weeks on day 28 post-inoculation followed by an eight-week recovery period. Results Decay analysis of incorporated 3H-hydroxyproline revealed the half-life of newly synthesized collagen to be significantly shorter in infected/inflamed prostates than in controls. Treatment with antibiotic enrofloxacin completely eradicated bacterial infection and allowed resolution of inflammation. This was followed by marked attenuation of collagen content and correlation analysis verified a positive association between the resolution of inflammation and the reversal of collagen deposition. Conclusions These data demonstrate, for the first time, that inflammation-induced prostatic fibrosis is a reversible process. PMID:25284058

  8. Weekly variability of precipitation induced by anthropogenic aerosols: A case study in Korea in summer 2004.

    SciTech Connect

    Bae, Soo Ya; Jeong, Jaein I.; Park, R.; Lim, Kyo-Sun; Hong, Song-You

    2016-01-06

    We examine the effect of anthropogenic aerosols on the weekly variability of precipitation in Korea in summer 2004 by using Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models. We con-duct two WRF simulations including a baseline simulation with empirically based cloud condensation nuclei (CCN) number concentrations and a sensitivity simulation with our implementation to account for the effect of aerosols on CCN number concentrations. The first simulation underestimates observed precipitation amounts, particularly in northeastern coastal areas of Korea, whereas the latter shows higher precipitation amounts that are in better agree-ment with the observations. In addition, the sensitivity model with the aerosol effects reproduces the observed weekly variability, particularly for precipitation frequency with a high R at 0.85, showing 20% increase of precipita-tion events during the weekend than those during weekdays. We find that the aerosol effect results in higher CCN number concentrations during the weekdays and a three-fold increase of the cloud water mixing ratio through en-hanced condensation. As a result, the amount of warm rain is generally suppressed because of the low auto-conversion process from cloud water to rain water under high aerosol conditions. The inefficient conversion, how-ever, leads to higher vertical development of clouds in the mid-atmosphere with stronger updrafts in the sensitivity model, which increases by 21% cold-phase hydrometeors including ice, snow, and graupel relative to the baseline model and ultimately results in higher precipitation amounts in summer.

  9. Kinetics and Equilibrium of Age-Induced Precipitation in Cu-4 At. Pct Ti Binary Alloy

    NASA Astrophysics Data System (ADS)

    Semboshi, Satoshi; Amano, Shintaro; Fu, Jie; Iwase, Akihiro; Takasugi, Takayuki

    2017-01-01

    Transformation kinetics and phase equilibrium of metastable and stable precipitates in age-hardenable Cu-4 at. pct Ti binary alloy have been investigated by monitoring the microstructural evolution during isothermal aging at temperatures between 693 K (420 °C) and 973 K (700 °C). The microstructure of the supersaturated solid solution evolves in four stages: compositional modulation due to spinodal decomposition, continuous precipitation of the needle-shaped metastable β'-Cu4Ti with a tetragonal structure, discontinuous precipitation of cellular components containing stable β-Cu4Ti lamellae with an orthorhombic structure, and eventually precipitation saturation at equilibrium. In specimens aged below 923 K (650 °C), the stable β-Cu4Ti phase is produced only due to the cellular reaction, whereas it can be also directly obtained from the intergranular needle-shaped β'-Cu4Ti precipitates in specimens aged at 973 K (700 °C). The precipitation kinetics and phase equilibrium observed for the specimens aged between 693 K (420 °C) and 973 K (700 °C) were characterized in accordance with a time-temperature-transformation (TTT) diagram and a Cu-Ti partial phase diagram, which were utilized to determine the alloy microstructure, strength, and electrical conductivity.

  10. Kinetics and Equilibrium of Age-Induced Precipitation in Cu-4 At. Pct Ti Binary Alloy

    NASA Astrophysics Data System (ADS)

    Semboshi, Satoshi; Amano, Shintaro; Fu, Jie; Iwase, Akihiro; Takasugi, Takayuki

    2017-03-01

    Transformation kinetics and phase equilibrium of metastable and stable precipitates in age-hardenable Cu-4 at. pct Ti binary alloy have been investigated by monitoring the microstructural evolution during isothermal aging at temperatures between 693 K (420 °C) and 973 K (700 °C). The microstructure of the supersaturated solid solution evolves in four stages: compositional modulation due to spinodal decomposition, continuous precipitation of the needle-shaped metastable β'-Cu4Ti with a tetragonal structure, discontinuous precipitation of cellular components containing stable β-Cu4Ti lamellae with an orthorhombic structure, and eventually precipitation saturation at equilibrium. In specimens aged below 923 K (650 °C), the stable β-Cu4Ti phase is produced only due to the cellular reaction, whereas it can be also directly obtained from the intergranular needle-shaped β'-Cu4Ti precipitates in specimens aged at 973 K (700 °C). The precipitation kinetics and phase equilibrium observed for the specimens aged between 693 K (420 °C) and 973 K (700 °C) were characterized in accordance with a time-temperature-transformation (TTT) diagram and a Cu-Ti partial phase diagram, which were utilized to determine the alloy microstructure, strength, and electrical conductivity.

  11. Weekly variability of precipitation induced by anthropogenic aerosols: A case study in Korea in summer 2004.

    PubMed

    Bae, Soo Ya; Jeong, Jaein I; Park, Rokjin J; Lim, Kyo-Sun Sunny; Hong, Song-You

    2016-01-15

    We examine the effect of anthropogenic aerosols on the weekly variability of precipitation in Korea in summer 2004 by using Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models. We conduct two WRF simulations including a baseline simulation with empirically based cloud condensation nuclei (CCN) number concentrations and a sensitivity simulation with our implementation to account for the effect of aerosols on CCN number concentrations. The first simulation underestimates observed precipitation amounts, particularly in northeastern coastal areas of Korea, whereas the latter shows higher precipitation amounts that are in better agreement with the observations. In addition, the sensitivity model with the aerosol effects reproduces the observed weekly variability, particularly for precipitation frequency with a high R at 0.85, showing 20% increase of precipitation events during the weekend than those during weekdays. We find that the aerosol effect results in higher CCN number concentrations during the weekdays and a three-fold increase of the cloud water mixing ratio through enhanced condensation. As a result, the amount of warm rain is generally suppressed because of the low auto-conversion process from cloud water to rain water under high aerosol conditions. The inefficient conversion, however, leads to higher vertical development of clouds in the mid-atmosphere with stronger updrafts in the sensitivity model, which increases by 21% cold-phase hydrometeors including ice, snow, and graupel relative to the baseline model and ultimately results in higher precipitation amounts in summer.

  12. The rapid degradation of bisphenol A induced by the response of indigenous bacterial communities in sediment.

    PubMed

    Huang, Chao; Xu, Piao; Zeng, Guangming; Huang, Danlian; Lai, Cui; Cheng, Min; Deng, Linjing; Zhang, Chen; Wan, Jia; Liu, Linshan

    2017-02-16

    In the present study, sediment was spiked with bisphenol A (BPA) solution to explore the interaction between indigenous bacterial communities and BPA biodegradation in sediment. Results showed that BPA could be adsorbed to the sediment and then biodegraded rapidly. Biodegradation efficiency of BPA in treatments with 10 and 50 mg/L BPA reached 64.3 and 61.8% on the first day, respectively. Quantitative polymerase chain reaction and denaturing gradient gel electrophoresis analysis indicated that BPA affected the densities, species, and diversities of bacteria significantly. The response of bacterial community to BPA favored BPA biodegradation by promoting the growth of BPA-reducing bacteria and inhibiting other competitors. According to the results of sequencing, Pseudomonas and Sphingomonas played vital roles in the degradation of BPA. They presented over 73% of the original bacterial community, and both of them were promoted by BPA comparing with controls. Laccase and polyphenol oxidase contributed to the degradation of BPA and metabolic intermediates, respectively. This paper illustrates the rapid biodegradation of BPA induced by the response of indigenous bacterial communities to the BPA stress, which will improve the understandings of BPA degradation in sediment.

  13. Pore-scale network modeling of microbially induced calcium carbonate precipitation: Insight into scale dependence of biogeochemical reaction rates

    NASA Astrophysics Data System (ADS)

    Qin, Chao-Zhong; Hassanizadeh, S. Majid; Ebigbo, Anozie

    2016-11-01

    The engineering of microbially induced calcium carbonate precipitation (MICP) has attracted much attention in a number of applications, such as sealing of CO2 leakage pathways, soil stabilization, and subsurface remediation of radionuclides and toxic metals. The goal of this work is to gain insight into pore-scale processes of MICP and scale dependence of biogeochemical reaction rates. This will help us develop efficient field-scale MICP models. In this work, we have developed a comprehensive pore-network model for MICP, with geochemical speciation calculated by the open-source PHREEQC module. A numerical pseudo-3-D micromodel as the computational domain was generated by a novel pore-network generation method. We modeled a three-stage process in the engineering of MICP including the growth of biofilm, the injection of calcium-rich medium, and the precipitation of calcium carbonate. A number of test cases were conducted to illustrate how calcite precipitation was influenced by different operating conditions. In addition, we studied the possibility of reducing the computational effort by simplifying geochemical calculations. Finally, the effect of mass transfer limitation of possible carbonate ions in a pore element on calcite precipitation was explored.

  14. The inhibiting effect of dislocation helices on the stress-induced orientation of S' precipitates in Al–Cu–Mg alloy

    SciTech Connect

    Guo, Xiaobin; Deng, Yunlai; Zhang, Jin; Zhang, Xinming

    2015-09-15

    The phenomenon of restrained stress-induced preferential orientation of S′ precipitates is investigated using a single-crystal of Al–1.23Cu–0.43 Mg alloy. Al–1.23Cu–0.43 Mg single-crystal specimens are subjected to stress aging, and the microstructure is analyzed by transmission electron microscopy (TEM). It is found that the stress-induced preferential orientation of S′ precipitates is restrained owing to the dislocations produced by a higher stress. The effect of dislocations on the oriented precipitates depends on the total length of the intersection lines for precipitate habit planes and dislocation glide planes. This investigation not only provides important insight into solving the anisotropy problem attributed to precipitation strengthening, but also offers a benchmark for choosing the appropriate stress range in manufacturing of Al–Cu–Mg alloys. - Highlights: • Single crystals of an Al–Cu–Mg alloy were prepared for the investigations. • A phenomenon of restrained stress-induced preferential orientation of S′ precipitates was found. • The influence of dislocation helices on precipitation during stress-aging was studied. • Difference of orientation degree of S′ precipitates and θ′ precipitates was explained. • A basis for choosing the appropriate stress range in manufacturing of Al–Cu–Mg alloys is provided.

  15. miR-155 suppresses bacterial clearance in Pseudomonas aeruginosa-induced keratitis by targeting Rheb.

    PubMed

    Yang, Kun; Wu, Minhao; Li, Meiyu; Li, Dandan; Peng, Anping; Nie, Xinxin; Sun, Mingxia; Wang, Jinli; Wu, Yongjian; Deng, Qiuchan; Zhu, Min; Chen, Kang; Yuan, Jin; Huang, Xi

    2014-07-01

    miR-155 (microRNA-155) is an important noncoding RNA in regulating host inflammatory responses. However, its regulatory role in ocular infection remains unclear. Our study first explored the function of miR-155 in Pseudomonas aeruginosa-induced keratitis, one of the most common sight-threatening ocular diseases. We found that miR-155 expression was enhanced in human and mouse corneas after P. aeruginosa infection and was mainly expressed in macrophages but not neutrophils. In vivo studies demonstrated that miR-155 knockout mice displayed more resistance to P. aeruginosa keratitis, with a higher inducible nitric oxide synthase level and a lower bacterial burden. More importantly, in vitro data indicated that miR-155 suppressed the macrophage-mediated bacterial phagocytosis and intracellular killing of P. aeruginosa by targeting Rheb (Ras homolog enriched in brain). To the best of our knowledge, this is the first study to explore the role of miR-155 in bacterial keratitis, which may provide a promising target for clinical treatment of P. aeruginosa keratitis and other infectious diseases.

  16. Soil pH effect on phosphate induced cadmium precipitation in Arable soil.

    PubMed

    Hong, Chang Oh; Owens, Vance N; Kim, Yong Gyun; Lee, Sang Mong; Park, Hyean Cheal; Kim, Keun Ki; Son, Hong Joo; Suh, Jeong Min; Kim, Pil Joo

    2014-07-01

    The objective of this study was to determine soil pH conditions that allow cadmium (Cd) to precipitate as Cd minerals in phosphate (P) amended soil. Cadmium immobilization could be attributed primarily to Cd adsorption due to increase in pH and negative charge. Soil pH might not affect Cd precipitation as Cd3(PO4)2 by direct reaction of Cd and P in the studied soil, even when soil pH increased up to 9.0. However, Cd might precipitate as CdCO3 with increasing pH up to 9.0 in P untreated soil and up to 8.0 in P treated soil depending on CO2 level.

  17. Middle atmosphere NO/x/ production due to ion propulsion induced radiation belt proton precipitation

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Jackman, C. H.

    1980-01-01

    The suggestion that keV Ar(+) resulting from ion propulsion operations during solar power satellite construction could cause energetic proton precipitation from the inner radiation belt is examined to determine if such precipitation could cause significant increases in middle atmosphere nitric oxide concentrations thereby adversely affecting stratospheric ozone. It is found that the initial production rate of NO (mole/cu cm-sec) at 50 km is 130 times that due to nitrous oxide reacting with excited oxygen. However, since the time required to empty the inner belt of protons is about 1 sec and short compared to the replenishment time due to neutron decay, precipitation of inner radiation belt protons will have no adverse atmospheric environmental effect.

  18. Location and chemical composition of microbially induced phosphorus precipitates in anaerobic and aerobic granular sludge.

    PubMed

    Mañas, A; Spérandio, M; Decker, F; Biscans, B

    2012-01-01

    This work focuses on combined scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) applied to granular sludge used for biological treatment of high-strength wastewater effluents. Mineral precipitation is shown to occur in the core of microbial granules under different operating conditions. Three dairy wastewater effluents, from three different upflow anaerobic sludge blanket (UASB) reactors and two aerobic granular sequenced batch reactors (GSBR) were evaluated. The relationship between the solid phase precipitation and the chemical composition of the wastewater was investigated with PHREEQC software (calculation of saturation indexes). Results showed that pH, Ca:P ratios and biological reactions played a major role in controlling the biomineralization phenomena. Thermodynamics calculations can be used to foresee the nature of bio-precipitates, but the location of the mineral concretions will need further investigation as it is certainly due to local microbial activity.

  19. Basagran(®) induces developmental malformations and changes the bacterial community of zebrafish embryos.

    PubMed

    Oliveira, Jacinta M M; Galhano, Victor; Henriques, Isabel; Soares, Amadeu M V M; Loureiro, Susana

    2017-02-01

    This study aimed to assess the effects of Basagran(®) on zebrafish (Danio rerio) embryos. The embryos were exposed to Basagran(®) at concentrations ranging from 120.0 to 480.6 mg/L, and the effects on embryo development (up to 96 h) and bacterial communities of 96 h-larvae were assessed. The embryo development response was time-dependent and concentration-dependent (106.35 < EC50 < 421.58 mg/L). The sensitivity of embryo-related endpoints decreased as follows: blood clotting in the head and/or around the yolk sac > delay or anomaly in yolk sac absorption > change in swimming equilibrium > development of pericardial and/or yolk sac oedema > scoliosis. A PCR-DGGE analysis was used to evaluate changes in the structure, richness, evenness and diversity of bacterial communities after herbicide exposure. A herbicide-induced structural adjustment of bacterial community was observed. In this study, it was successfully demonstrated that Basagran(®) affected zebrafish embryos and associated bacterial communities, showing time-dependent and concentration-dependent embryos' developmental response and structural changes in bacterial community. Thus, this work provides for the first time a complementary approach, which is useful to derive robust toxicity thresholds considering the embryo-microbiota system as a whole. The aquatic hazard assessment will be strengthened by combining current ecotoxicological tests with molecular microbiology tools.

  20. Influences on the Emissions of Bacterial Plasmas Generated through Nanosecond Laser-Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Malenfant, Dylan J.

    In the past decade, laser-induced breakdown spectroscopy has been shown to provide compositional data that can be used for discrimination between bacterial specimens at the strain level. This work demonstrates the viability of this technique in a clinical setting. Studies were conducted to investigate the impact of emissions generated by a nitrocellulose filter paper background on the classification of four species: E. coli, S. epidermidis, M. smegmatis, and P. aeruginosa. Limits of detection were determined as 48+/-12 kCFU per ablation event for new mounting procedures using standard diagnostic laboratory techniques, and a device for centrifuge filtration was designed for sampling from low-titer bacterial suspensions. Plasma emissions from samples grown at biological levels of magnesium, zinc, and glucose were shown not to deviate from controls. A limit of detection for environmental zinc was found to be 11 ppm. Discrimination with heat-killed samples was demonstrated, providing a sterile diagnostic environment.

  1. Bacterial lipopolysaccharides induce in vitro degradation of cartilage matrix through chondrocyte activation.

    PubMed Central

    Jasin, H E

    1983-01-01

    The present studies demonstrate that bacterial lipopolysaccharides (LPS) induce cartilage matrix degradation in live explants in organ culture. Quintuplicate bovine nasal fibrocartilage explants cultured for 8 d with three different purified LPS preparations derived from Escherichia coli and Salmonella typhosa at concentrations ranging from 1.0 to 25.0 micrograms/ml resulted in matrix proteoglycan depletion of 33.3 +/- 5.8 to 92.5 +/- 2.0% (medium control depletion 17.7 +/- 0.7 to 32.4 +/- 1.4%). Matrix degradation depended on the presence of live chondrocytes because frozen-thawed explants incubated with LPS failed to show any proteoglycan release. Moreover, the addition of Polymyxin B (25 micrograms/ml) to live explants incubated with LPS abolished matrix release, whereas Polymyxin B had no effect on the matrix-degrading activity provided by blood mononuclear cell factors. A highly purified Lipid A preparation induced matrix degradation at a concentration of 0.01 micrograms/ml. Cartilage matrix collagen and proteoglycan depletion also occurred with porcine articular cartilage explants (collagen release: 18.3 +/- 3.5%, medium control: 2.1 +/- 0.5%; proteoglycan release: 79.0 +/- 5.9%, medium control: 28.8 +/- 4.8%). Histochemical analysis of the cultured explants confirmed the results described above. Gel chromatography of the proteoglycans released in culture indicated that LPS induced significant degradation of the high molecular weight chondroitin sulfate-containing aggregates. These findings suggest that bacterial products may induce cartilage damage by direct stimulation of chondrocytes. This pathogenic mechanism may play a role in joint damage in septic arthritis and in arthropathies resulting from the presence of bacterial products derived from the gastrointestinal tract. Images PMID:6358260

  2. Sympathetic activity induced by naloxone-precipitated morphine withdrawal is blocked in genetically engineered mice lacking functional CRF1 receptor

    SciTech Connect

    García-Carmona, Juan-Antonio; Martínez-Laorden, Elena; Milanés, María-Victoria; Laorden, María-Luisa

    2015-02-15

    There is large body evidence indicating that stress can lead to cardiovascular disease. However, the exact brain areas and the mechanisms involved remain to be revealed. Here, we performed a series of experiments to characterize the role of CRF1 receptor (CRF1R) in the stress response induced by naloxone-precipitated morphine withdrawal. The experiments were performed in the hypothalamic paraventricular nucleus (PVN) ventrolateral medulla (VLM), brain regions involved in the regulation of cardiovascular activity, and in the right ventricle by using genetically engineered mice lacking functional CRF1R levels (KO). Mice were treated with increasing doses of morphine and withdrawal was precipitated by naloxone administration. Noradrenaline (NA) turnover, c-Fos, expression, PKA and TH phosphorylated at serine 40, was evaluated by high-performance liquid chromatography (HPLC), immunohistochemistry and immunoblotting. Morphine withdrawal induced an enhancement of NA turnover in PVN in parallel with an increase in TH neurons expressing c-Fos in VLM in wild-type mice. In addition we have demonstrated an increase in NA turnover, TH phosphorylated at serine 40 and PKA levels in heart. The main finding of the present study was that NA turnover, TH positive neurons that express c-Fos, TH phosphorylated at serine 40 and PKA expression observed during morphine withdrawal were significantly inhibited in CRF1R KO mice. Our results demonstrate that CRF/CRF1R activation may contribute to the adaptive changes induced by naloxone-precipitated withdrawal in the heart and in the brain areas which modulate the cardiac sympathetic function and suggest that CRF/CRF1R pathways could be contributing to cardiovascular disease associated to opioid addiction. - Highlights: • Naloxone-precipitated morphine withdrawal increases sympathetic activity in the PVN and heart. • Co-localization of TH phosphorylated at serine 40/c-Fos in the VLM after morphine withdrawal • Naloxone-precipitated

  3. Cerulein-induced acute pancreatitis in rats--does bacterial translocation occur via a transperitoneal pathway?

    PubMed

    Arendt, T; Wendt, M; Olszewski, M; Falkenhagen, U; Stoffregen, C; Fölsch, U R

    1997-10-01

    Bacterial infectious complications are the most common cause of morbidity and mortality associated with acute pancreatitis. Most pathogens are common gastrointestinal flora, indicating that the gut is the source of pancreatitis-related infections. However, the route whereby the microorganisms reach distant organs remains speculative. We tested the hypothesis that spread of bacteria occurs via a transperitoneal pathway. Acute interstitial pancreatitis (AIP) was induced in antibiotic (gentamicin, bacithracin, neomycin)-decontaminated rats by intravenous infusion of cerulein. Effects of pancreatic necrosis (PN) were studied in rats that received additional injections into the peritoneal cavity of pancreatic tissue obtained from donor rats. The rats were inoculated with Escherichia coli (O2:KN:H18) resistant to the antibiotics used for decontamination either orally (10(12) microorganisms; experiment I) or intraperitoneally (10(8) microorganisms; experiment II). Moreover, the rat peritoneal cavity wash was inoculated with 10(8) E. coli in vitro (experiment III). In rats with AIP and PN, recovery of the bacteria from liver, spleen, pancreas, lung, and blood following oral inoculation demonstrated that acute pancreatitis promotes bacterial translocation from the gut. The absence of E. coli in these organs following intraperitoneal inoculation showed that the bacteria do not spread from the peritoneal cavity. Rats with PN cleared E. coli from the peritoneal cavity in a shorter period than rats with AIP and controls (5 vs. 7 and 8 days; p < 0.05). The multiplication rate of E. coli in peritoneal cavity wash was lower in rats with PN than in rats with AIP and controls (p < 0.01). We conclude that (1) translocation of E. coli from the gut during cerulein-induced acute pancreatitis occurs via nonperitoneal pathways, (2) the peritoneal cavity acts as a trap for the bacteria rather than a source of bacterial seeding, and (3) PN impairs survival of E. coli in the peritoneal

  4. Investigation of cascade-induced re-solution from nanometer sized coherent precipitates in dilute Fe-Cu alloys

    NASA Astrophysics Data System (ADS)

    Certain, A.; Lee Voigt, H.-J.; Allen, T. R.; Wirth, B. D.

    2013-01-01

    Molecular dynamics (MD) simulations have been used to investigate the re-solution of copper atoms from coherent, nanometer-sized copper precipitates in a body-centered cubic iron matrix. The molecular dynamics simulations used Finnis-Sinclair type interatomic potentials to describe the Fe-Cu system. Precipitate diameters of 1, 3 and 5 nm were studied, with primary knock-on atom (PKA) from 1 to 100 keV, although the majority of the cascade simulations and analysis of solute re-solution were performed for cascades of 10 or 20 keV. The simulation results provide an assessment of the re-solution on a per-atom basis as a function of precipitate size, cascade location and energy. Smaller sized precipitates, with a larger surface to volume ratio, experienced larger re-solution on a per-atom basis than larger precipitates. Re-solution was observed to occur predominantly in the initial ballistic stages of the cascades when atomic collisions occur at high kinetic energy. A minimum PKA energy of around 1 keV was required to produce re-solution, and the amount of re-solution appears to saturate for PKA energies above approximately 10 keV, indicating that the MD results are representative of the energy range of interest. A model for prompt, cascade induced solute atom re-solution has been derived, following the approach used to describe fission gas bubble re-solution, and the parameters for describing copper atom re-solution are provided.

  5. Misfit-induced changes of lattice parameters in two-phase systems: coherent/incoherent precipitates in a matrix

    PubMed Central

    Akhlaghi, Maryam; Steiner, Tobias; Meka, Sai Ramudu; Mittemeijer, Eric Jan

    2016-01-01

    Elastic accommodation of precipitation-induced or thermally induced misfit leads to lattice-parameter changes in crystalline multi-phase systems. Formulae for calculation of such misfit-induced lattice-parameter changes are presented for the aggregate (matrix + second-phase particles) and for the individual matrix and second phase, recognizing the occurrence of either coherent or incoherent diffraction by the matrix and second-phase particles. An overview and an (re)interpretation on the above basis is presented of published lattice-parameter data, obtained by X-ray diffraction analyses of aggregates of matrix plus second-phase particles. Examples for three types of systems consisting of a matrix with misfitting second-phase particles are dealt with, which differ in the origin of the misfit (precipitation or thermally induced) and in the type of diffraction (coherent or incoherent diffraction of matrix plus second-phase particles). The experimental data are shown to be in good to very good agreement with predictions according to the current treatment. PMID:26937236

  6. Femtosecond laser-induced oriented precipitation of Ba2TiGe2O8 crystals in glass.

    PubMed

    Dai, Ye; Ma, Hongliang; Lu, Bo; Yu, Bingkun; Zhu, Bin; Qiu, Jianrong

    2008-03-17

    Ba(2)TiGe(2)O(8) crystals were selectively precipitated on femtosecond laser irradiated BaO-TiO(2)-GeO(2) glass surface. Furthermore, the crystal could grow from the surface of glass to the interior towards the laser movement direction when the laser focus was continuously moved. The laser-induced crystal was confirmed to be Ba(2)TiGe(2)O(8) phase by x-ray diffraction analysis and micro-Raman spectra. We also observed blue light due to double-frequency conversion of the 800nm incident laser in the crystallized regions. We propose the observed phenomena resulted from the femtosecond laser-assisted orientation of precipitation of crystal.

  7. Global-warming-induced Increases in Extreme Precipitation are Smallest over Mountains

    NASA Astrophysics Data System (ADS)

    Shi, X.; Durran, D. R.

    2015-12-01

    Climate-model simulations predict an intensification of extreme precipitation in almost all areas of the world under global warming. Geographical variations in the magnitude of this intensification are clearly evident in the simulations, but most previous efforts to understand the factors responsible for the changes in extreme precipitation have focused on zonal averages, neglecting the variations that occur in different regions at the same latitude. Here we present climate-model simulations for an ocean-covered earth having simple idealized continents with north-south mountain barriers in its northern midlatitudes. We show that the sensitivity of extreme precipitation to increases in the global mean surface temperature is 3 %/K lower over the mountains than over the oceans and the plains. Fundamental factors responsible for changes in precipitation intensity may be divided between thermodynamic effects, arising through changes in temperature and moisture, and dynamical effects, produced by changes in the ascent rates of saturated air parcels. The difference in sensitivity among these regions is not due to thermodynamic effects, but rather to differences between the gravity-wave dynamics governing vertical velocities over the mountains and the cyclone dynamics governing vertical motions over the oceans and plains.

  8. On the effect of the injection of potassium phosphate in vivo inducing the precipitation of serum calcium with inorganic phosphate

    PubMed Central

    Soares, Alcimar B; Ticianeli, José G; Soares, Letícia B M; Amaro, George

    2013-01-01

    High concentrations of inorganic phosphate (Pi) resulted from the hydrolysis of ATP is strongly associated to the weakness of the contractile mechanism of muscles due to its attractiveness to calcium. The majority of the experiments to study such effect are conducted in vitro. This work investigates the effects of different concentrations of Pi, induced by the injection of potassium phosphate in live animals, in the precipitation with serum calcium and the generation of calcium phosphate composites. The experiments were also designed to find out the ideal amount of potassium phosphate to induce an effective reaction. Potassium phosphate was injected in Wistar rats, randomly separated and distributed into seven groups. Group I was injected with 0.5 ml of saline solution (control) and groups II through VII were injected with 0.5, 1.5, 2.5, 5.0, 7.5 and 10.0 mg/kg of potassium phosphate, respectively. Blood collected from the inferior vena cava was submitted to biochemical analyses to measure the concentrations of calcium, Pi, urea and creatinine. The results showed that Pi, induced by the injection of potassium phosphate in live animals, causes precipitation with serum calcium, with statistically significant differences between the control and the treatment groups for doses up to 5.0 mg/kg. No statistically significant differences were found between the different doses and the concentration of urea and creatinine in the plasma. We conclude that potassium phosphate can be used to induce serum calcium precipitation in-vivo, with minor effects on other physiological variables, and the ideal dose to do so is 5.0 mg/kg. PMID:24379908

  9. Critical role of bacterial isochorismatase in the autophagic process induced by Acinetobacter baumannii in mammalian cells

    PubMed Central

    Wang, Yang; Zhang, Kaiyu; Shi, Xiaochen; Wang, Chao; Wang, Feng; Fan, Junwen; Shen, Fengge; Xu, Jiancheng; Bao, Wanguo; Liu, Mingyuan; Yu, Lu

    2016-01-01

    A recent study reported that Acinetobacter baumannii could induce autophagy, but the recognition and clearance mechanism of intracytosolic A. baumannii in the autophagic process and the molecular mechanism of autophagy induced by the pathogen remains unknown. In this study, we first demonstrated that invading A. baumannii induced a complete, ubiquitin-mediated autophagic response that is dependent upon septins SEPT2 and SEPT9 in mammalian cells. We also demonstrated that autophagy induced by A. baumannii was Beclin-1 dependent via the AMPK/ERK/mammalian target of rapamycin pathway. Of interest, we found that the isochorismatase mutant strain had significantly decreased siderophore-mediated ferric iron acquisition ability and had a reduced the ability to induce autophagy. We verified that isochorismatase was required for the recognition of intracytosolic A. baumannii mediated by septin cages, ubiquitinated proteins, and ubiquitin-binding adaptor proteins p62 and NDP52 in autophagic response. We also confirmed that isochorismatase was required for the clearance of invading A. baumannii by autophagy in vitro and in the mouse model of infection. Together, these findings provide insight into the distinctive recognition and clearance of intracytosolic A. baumannii by autophagy in host cells, and that isochorismatase plays a critical role in the A. baumannii–induced autophagic process.—Wang, Y., Zhang, K., Shi, X., Wang, C., Wang, F., Fan, J., Shen, F., Xu, J., Bao, W., Liu, M., Yu, L. Critical role of bacterial isochorismatase in the autophagic process induced by Acinetobacter baumannii in mammalian cells. PMID:27432399

  10. Reactive Transport Modeling of Induced Calcite Precipitation Reaction Fronts in Porous Media Using A Parallel, Fully Coupled, Fully Implicit Approach

    NASA Astrophysics Data System (ADS)

    Guo, L.; Huang, H.; Gaston, D.; Redden, G. D.; Fox, D. T.; Fujita, Y.

    2010-12-01

    Inducing mineral precipitation in the subsurface is one potential strategy for immobilizing trace metal and radionuclide contaminants. Generating mineral precipitates in situ can be achieved by manipulating chemical conditions, typically through injection or in situ generation of reactants. How these reactants transport, mix and react within the medium controls the spatial distribution and composition of the resulting mineral phases. Multiple processes, including fluid flow, dispersive/diffusive transport of reactants, biogeochemical reactions and changes in porosity-permeability, are tightly coupled over a number of scales. Numerical modeling can be used to investigate the nonlinear coupling effects of these processes which are quite challenging to explore experimentally. Many subsurface reactive transport simulators employ a de-coupled or operator-splitting approach where transport equations and batch chemistry reactions are solved sequentially. However, such an approach has limited applicability for biogeochemical systems with fast kinetics and strong coupling between chemical reactions and medium properties. A massively parallel, fully coupled, fully implicit Reactive Transport simulator (referred to as “RAT”) based on a parallel multi-physics object-oriented simulation framework (MOOSE) has been developed at the Idaho National Laboratory. Within this simulator, systems of transport and reaction equations can be solved simultaneously in a fully coupled, fully implicit manner using the Jacobian Free Newton-Krylov (JFNK) method with additional advanced computing capabilities such as (1) physics-based preconditioning for solution convergence acceleration, (2) massively parallel computing and scalability, and (3) adaptive mesh refinements for 2D and 3D structured and unstructured mesh. The simulator was first tested against analytical solutions, then applied to simulating induced calcium carbonate mineral precipitation in 1D columns and 2D flow cells as analogs

  11. Helminth-induced alterations of the gut microbiota exacerbate bacterial colitis.

    PubMed

    Su, C; Su, L; Li, Y; Long, S R; Chang, J; Zhang, W; Walker, W A; Xavier, R J; Cherayil, B J; Shi, H N

    2017-03-29

    Infection with the intestinal helminth parasite Heligmosomoides polygyrus exacerbates the colitis caused by the bacterial enteropathogen Citrobacter rodentium. To clarify the underlying mechanism, we analyzed fecal microbiota composition of control and helminth-infected mice and evaluated the functional role of compositional differences by microbiota transplantation experiments. Our results showed that infection of Balb/c mice with H. polygyrus resulted in significant changes in the composition of the gut microbiota, characterized by a marked increase in the abundance of Bacteroidetes and decreases in Firmicutes and Lactobacillales. Recipients of the gut microbiota from helminth-infected wide-type, but not STAT6-deficient, Balb/c donors had increased fecal pathogen shedding and significant worsening of Citrobacter-induced colitis compared to recipients of microbiota from control donors. Recipients of helminth-altered microbiota also displayed increased regulatory T cells and IL-10 expression. Depletion of CD4(+)CD25(+) T cells and neutralization of IL-10 in recipients of helminth-altered microbiota led to reduced stool C. rodentium numbers and attenuated colitis. These results indicate that alteration of the gut microbiota is a significant contributor to the H. polygyrus-induced exacerbation of C. rodentium colitis. The helminth-induced alteration of the microbiota is Th2-dependent and acts by promoting regulatory T cells that suppress protective responses to bacterial enteropathogens.Mucosal Immunology advance online publication 29 March 2017 doi:10.1038/mi.2017.20.

  12. Inducible Expression of Transmembrane Proteins on Bacterial Magnetic Particles in Magnetospirillum magneticum AMB-1▿

    PubMed Central

    Yoshino, Tomoko; Shimojo, Akiko; Maeda, Yoshiaki; Matsunaga, Tadashi

    2010-01-01

    Bacterial magnetic particles (BacMPs) produced by the magnetotactic bacterium Magnetospirillum magneticum AMB-1 are used for a variety of biomedical applications. In particular, the lipid bilayer surrounding BacMPs has been reported to be amenable to the insertion of recombinant transmembrane proteins; however, the display of transmembrane proteins in BacMP membranes remains a technical challenge due to the cytotoxic effects of the proteins when they are overexpressed in bacterial cells. In this study, a tetracycline-inducible expression system was developed to display transmembrane proteins on BacMPs. The expression and localization of the target proteins were confirmed using luciferase and green fluorescent protein as reporter proteins. Gene expression was suppressed in the absence of anhydrotetracycline, and the level of protein expression could be controlled by modulating the concentration of the inducer molecule. This system was implemented to obtain the expression of the tetraspanin CD81. The truncated form of CD81 including the ligand binding site was successfully displayed at the surface of BacMPs by using Mms13 as an anchor protein and was shown to bind the hepatitis C virus envelope protein E2. These results suggest that the tetracycline-inducible expression system described here will be a useful tool for the expression and display of transmembrane proteins in the membranes of BacMPs. PMID:20038711

  13. Independent Effects of a Herbivore's Bacterial Symbionts on Its Performance and Induced Plant Defences.

    PubMed

    Staudacher, Heike; Schimmel, Bernardus C J; Lamers, Mart M; Wybouw, Nicky; Groot, Astrid T; Kant, Merijn R

    2017-01-18

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant's response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant's defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly.

  14. Independent Effects of a Herbivore’s Bacterial Symbionts on Its Performance and Induced Plant Defences

    PubMed Central

    Staudacher, Heike; Schimmel, Bernardus C. J.; Lamers, Mart M.; Wybouw, Nicky; Groot, Astrid T.; Kant, Merijn R.

    2017-01-01

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant’s response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant’s defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly. PMID:28106771

  15. Immune responses and protection induced by Brucella suis S2 bacterial ghosts in mice.

    PubMed

    Liu, Jun; Li, Yi; Sun, Yang; Ji, Xue; Zhu, Lingwei; Guo, Xuejun; Zhou, Wei; Zhou, Bo; Liu, Shuang; Zhang, Ruian; Feng, Shuzhang

    2015-08-15

    With the purpose of generating Brucella suis bacterial ghosts and investigating the immunogenicity of bacterial ghosts as a vaccine candidate, the lysis gene E and temperature-sensitive regulator cassette were cloned into a shuttle plasmid, pBBR1MCS-2, for construction of a recombinant temperature-sensitive shuttle lysis plasmid, pBBR1MCS-E. pBBR1MCS-E was then introduced into attenuated B. suis live vaccine S2 bacteria, and the resultant transformants were used for production of B. suis ghosts (BSGs) by inducing lysis gene E expression. The BSGs were characterized by observing their morphology by transmission electron microscopy. The safety and immunogenicity of BSGs were further evaluated using a murine model, the result suggested that BSG was as safe as formalin-killed B. suis. In mice, BSG demonstrated a similar capacity of inducing pathogen-specific serum IgG antibody response, spleen CD3(+) and CD4(+) T cell responses, induce secretion of gamma interferon and interleukin-4, and protection levels against Brucella melitensis 16M challenge, as the attenuated B. suis live vaccine. These data suggesting that BSG could confer protection against Brucella infection in a mouse model of disease and may be developed as a new vaccine candidate against Brucella infection.

  16. Impact of bacterial colonization on the severity, and accompanying airway inflammation, of virus-induced wheezing in children.

    PubMed

    Yu, D; Wei, L; Zhengxiu, L; Jian, L; Lijia, W; Wei, L; Xiqiang, Y; Xiaodong, Z; Zhou, F; Enmei, L

    2010-09-01

    It is reported that bacterial colonization of the airway in neonates affects the likelihood and severity of subsequent wheezing in childhood. This study aimed to explore the impact of bacterial colonization on the severity of virus-induced wheezing, and accompanying airway inflammation. Nasopharyngeal aspirates (NPAs) from 68 hospitalized children with bronchiolitis and 85 children with recurrent wheezing were obtained. Eleven common respiratory viruses were sought by PCR and/or direct fluorescence assay. Bacteria were isolated from NPAs by routine culture methods. Cell numbers and concentrations of cytokines/chemokines in the NPAs were measured, and nucleated cells were characterized. The frequency of bacterial colonization in children with recurrent wheezing was significantly higher than in children with an initial attack of bronchiolitis. Bacterial colonization accompanying virus infection had no effect on clinical manifestations, duration of hospitalization, concentrations of cytokines/chemokines (except interleukin-10 (IL-10)) or cellularity in the children with bronchiolitis; however, among the children with recurrent wheezing, those who had coexistent non-invasive bacterial colonization and virus infection presented more frequent cyanosis, longer duration of hospitalization, a higher concentration of IL-10 and a higher percentage of neutrophils in NPAs than those with virus infection but without bacterial colonization. Bacterial colonization was common in children with virus-induced wheezing, particularly in the situation of recurrent wheezing. To some extent, bacterial colonization accompanying virus infection may contribute to the severity of the wheezing because of its impact on airway inflammation.

  17. Bacterially induced stolon settlement in the scyphopolyp of Aurelia aurita (Cnidaria, Scyphozoa)

    NASA Astrophysics Data System (ADS)

    Schmahl, G.

    1985-03-01

    Unsettled stoloniferous scyphopolyps of Aurelia aurita Lamarck were offered different substrates for settlement under defined conditions. On addition of different biogenic and abiotic substrates, a pure strain of bacteria, a species of Micrococcaceae, was observed to trigger the settlement of the stolon. The settlement reaction only takes place following direct contact with the bacteria; sterile filtrated culture medium of the same bacterial strain was not able to induce settlement. The bacteria were found to be effective on stolon settlement during the logarithmic growth phase, but not during the stationary phase.

  18. Bacterial Peptidoglycan Transverses the Placenta to Induce Fetal Neuroproliferation and Aberrant Postnatal Behavior

    PubMed Central

    Humann, Jessica; Mann, Beth; Gao, Geli; Moresco, Philip; Ramahi, Joseph; Loh, Lip Nam; Farr, Arden; Hu, Yunming; Durick-Eder, Kelly; Fillon, Sophie A.; Smeyne, Richard J.; Tuomanen, Elaine I.

    2016-01-01

    Summary Maternal infection during pregnancy is associated with adverse outcomes for the fetus, including postnatal cognitive disorders. However, the underlying mechanisms are obscure. We find that bacterial cell wall peptidoglycan (CW), a universal PAMP for TLR2, traverses across the murine placenta into the developing fetal brain. In contrast to adults, CW-exposed fetal brains did not show any signs of inflammation or neuronal death. Instead, the neuronal transcription factor FoxG1 was induced and neuroproliferation leading to a 50% greater density of neurons in the cortical plate was observed. Bacterial infection of pregnant dams followed by antibiotic treatment, which releases CW, yielded the same result. Neuroproliferation required TLR2 and was recapitulated in vitro with fetal neuronal precursor cells and TLR2/6, but not TLR2/1 ligands. The fetal neuroproliferative response correlated with abnormal cognitive behavior in CW-exposed pups following birth. Thus, the bacterial CW-TLR2 signaling axis affects fetal neurodevelopment and may underlie postnatal cognitive disorders. PMID:26962947

  19. Nutrient reduction induced stringent responses promote bacterial quorum-sensing divergence for population fitness

    PubMed Central

    Zhao, Kelei; Zhou, Xikun; Li, Wujiao; Zhang, Xiuyue; Yue, Bisong

    2016-01-01

    Bacteria use a cell-cell communication system termed quorum-sensing (QS) to adjust population size by coordinating the costly but beneficial cooperative behaviors. It has long been suggested that bacterial social conflict for expensive extracellular products may drive QS divergence and cause the “tragedy of the commons”. However, the underlying molecular mechanism of social divergence and its evolutionary consequences for the bacterial ecology still remain largely unknown. By using the model bacterium Pseudomonas aeruginosa PAO1, here we show that nutrient reduction can promote QS divergence for population fitness during evolution but requiring adequate cell density. Mechanically, decreased nutrient supplies can induce RpoS-directed stringent response and enhance the selection pressure on lasR gene, and lasR mutants are evolved in association with the DNA mismatch repair “switch-off”. The lasR mutants have higher relative fitness than QS-intact individuals due to their energy-saving characteristic under nutrient decreased condition. Furthermore an optimal incorporation of lasR mutants is capable of maximizing the fitness of entire population during in vitro culture and the colonization in mouse lung. Consequently, rather than worsen the population health, QS-coordinated social divergence is an elaborate evolutionary strategy that renders the entire bacterial population more fit in tough times. PMID:27713502

  20. Parallel changes of taxonomic interaction networks in lacustrine bacterial communities induced by a polymetallic perturbation

    PubMed Central

    Laplante, Karine; Sébastien, Boutin; Derome, Nicolas

    2013-01-01

    Heavy metals released by anthropogenic activities such as mining trigger profound changes to bacterial communities. In this study we used 16S SSU rRNA gene high-throughput sequencing to characterize the impact of a polymetallic perturbation and other environmental parameters on taxonomic networks within five lacustrine bacterial communities from sites located near Rouyn-Noranda, Quebec, Canada. The results showed that community equilibrium was disturbed in terms of both diversity and structure. Moreover, heavy metals, especially cadmium combined with water acidity, induced parallel changes among sites via the selection of resistant OTUs (Operational Taxonomic Unit) and taxonomic dominance perturbations favoring the Alphaproteobacteria. Furthermore, under a similar selective pressure, covariation trends between phyla revealed conservation and parallelism within interphylum interactions. Our study sheds light on the importance of analyzing communities not only from a phylogenetic perspective but also including a quantitative approach to provide significant insights into the evolutionary forces that shape the dynamic of the taxonomic interaction networks in bacterial communities. PMID:23789031

  1. Antibiotic-induced change of bacterial communities associated with the copepod Nitocra spinipes.

    PubMed

    Edlund, Anna; Ek, Karin; Breitholtz, Magnus; Gorokhova, Elena

    2012-01-01

    Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts.

  2. [Joint effects of apoptosis induced by microcystins and bacterial lipopolysaccharides on grass carp (Ctenopharyngodon idellus) lymphocytes].

    PubMed

    Fang, Wen-Di; Zhang, Hang-Jun; Wu, Yu-Huan

    2014-02-01

    In this study, grass carp (Ctenopharyngodon idellus) lymphocytes were used as the vitro test object to demonstrate the joint effects of microcystins (MC-LR) and bacterial lipopolysaccharides (LPS) on fish immune system. The results showed that MC-LR and LPS in the single and combined exposure groups could both induce grass carp lymphocytes apoptosis with typical ladder-like DNA electrophoresis characteristics. However, comparing the apoptosis rate of the combined and single exposure groups, it was suggested that bacterial LPS could cooperate with MC-LR causing a higher rate of fish lymphocytes apoptosis (2.1 and 3.3-fold of that for the single exposure group I (MC-LR) and II (LPS), respectively), and there existed a significant dose-response relationship. The MC-LR cooperating with bacterial LPS decreased the activity of glutathione S-transferase (GST), increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), resulted in DNA damage and cell arrest in G0 phase, which inhibited cell proliferation and accelerated apoptosis. It was proved that MC-LR exacerbated fish immunotoxicity by collaborating with LPS, which had a serious adverse effect on aquaculture industry.

  3. Antibiotic-Induced Change of Bacterial Communities Associated with the Copepod Nitocra spinipes

    PubMed Central

    Edlund, Anna; Ek, Karin; Breitholtz, Magnus; Gorokhova, Elena

    2012-01-01

    Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts. PMID:22427962

  4. Refining hot-water extracted silk sericin by ethanol-induced precipitation.

    PubMed

    Oh, Hanjin; Lee, Ji Young; Kim, Moo Kon; Um, In Chul; Lee, Ki Hoon

    2011-01-01

    In order to improve some inherent disadvantages in the mechanical properties of silk sericin (SS), we prepared ethanol-precipitated sericin (EpSS) by adding ethanol into hot-water extracted sericin (HS) solution. EpSS had higher viscosity compared to HS and it was due to the differences in their molecular weight distribution (MWD). The different MWD of EpSS was due to the different solubility of sericin molecules at various concentrations of ethanol, and the amino acid composition of EpSS showed that the more hydrophobic sericin is precipitated more readily in the presence of ethanol. The secondary structure of sericin is also changed from a random coil to β-sheet structure when the amount of ethanol added is high enough. The DSC analysis also revealed that EpSSs has a more compact structure. Finally, when beads were prepared from EpSS, they had enhanced compressive strength compared to those from HS.

  5. Aragonite precipitation induced by anaerobic oxidation of methane in shallow-water seeps, Tyrrhenian Sea, Italy

    NASA Astrophysics Data System (ADS)

    Wiedling, Johanna; Kuhfuß, Hanna; Lott, Christian; Böttcher, Michael E.; Lichtschlag, Anna; Wegener, Gunter; Deusner, Christian; Bach, Wolfgang; Weber, Miriam

    2014-05-01

    In the shallow-water organic-poor silicate sands off the West coast of Elba, Italy, we found aragonite precipitates within a radius of 10 cm to methane seeps in 20 - 40 cm sediment depth. The shallow seep site was mapped by SCUBA diving and in an area of 100 m2 nine gas emission spots were observed. The gas emission, containing 73 Vol. % methane, was measured to be 0.72 L m-2 d-1. Findings of anaerobic methane oxidizing archea (ANME 1, 2, 2a, 2b) and sulphate reducing bacteria (SRB) as well as in vitro rate measurements of anaerobic oxidation of methane (AOM) with a maximum of 67 ± 7 nmol CH4 cm-3 d-1 led to the hypothesis that carbonate precipitation is coupled to these microbial processes. Porewater analysis showed elevated concentrations of dissolved inorganic carbon (DIC) (up to 15.5 mmol L-1) and hydrogen sulfide (up to 6.6 mmol L-1). The presence of bicarbonate and the ambient temperature (14 - 25 ° C) facilitate the precipitation of needle-shaped aragonite. Oxygen isotope compositions of the mineral are consistent with the ambient temperatures and may indicate a recent diagenetic formation of this mineral. Although precipitation should not be preserved in these sandy permeable sediments, influenced by seasonality, wave action, and fluid flow, we found up to 10-50 cm3 irregular pieces of cemented sand grains, very often encrusting dead seagrass rhizomes. Commonly known carbonate structures, especially from the deep sea, are chimneys, mounds, hardgrounds and nodules. These structures are well known from seep and vent sites, usually showing the same range of stable carbon isotope fractionation as the escaping methane. The permeable sediment at the Elba site possibly allows the gas to frequently change its pathway to the sediment surface and thus precipitation can occure at several spots and more irregular than in the reported sites. Preservation of precipitates, however, requires sufficient authigenic aragonite to be formed before fluid dynamics changed the

  6. Microbial phytase-induced calcium-phosphate precipitation--a potential soil stabilization method.

    PubMed

    Roeselers, G; Van Loosdrecht, M C M

    2010-11-01

    Two hypotheses were tested: (1) microbial dephosphorylation of phytate in the presence of Ca²+ ions will result in the precipitation of hydroxyapatite-like crystals and (2) precipitation of calcium-phosphate crystals on and between sand-like particles can cause cementation. A growing culture of the dimorphic phytase-active yeast Arxula adeninivorans was introduced into a column filled with quartz particles and subsequently a liquid growth medium amended with calcium phytate was pumped through the column resulting in increased strength and stiffness of the quartz particle matrix. Environmental scanning electron microscope analysis combined with energy-dispersive X-ray measurement revealed cementation of the quartz particles by calcium-phosphate crystals. This microbial mineralization process could provide a novel approach to improving the mechanical properties like strength and stiffness of sandy soils.

  7. On the basin-scale detection and attribution of human-induced climate change in monsoon precipitation and streamflow

    NASA Astrophysics Data System (ADS)

    Mondal, Arpita; Mujumdar, P. P.

    2012-10-01

    Detecting and quantifying the presence of human-induced climate change in regional hydrology is important for studying the impacts of such changes on the water resources systems as well as for reliable future projections and policy making for adaptation. In this article a formal fingerprint-based detection and attribution analysis has been attempted to study the changes in the observed monsoon precipitation and streamflow in the rain-fed Mahanadi River Basin in India, considering the variability across different climate models. This is achieved through the use of observations, several climate model runs, a principal component analysis and regression based statistical downscaling technique, and a Genetic Programming based rainfall-runoff model. It is found that the decreases in observed hydrological variables across the second half of the 20th century lie outside the range that is expected from natural internal variability of climate alone at 95% statistical confidence level, for most of the climate models considered. For several climate models, such changes are consistent with those expected from anthropogenic emissions of greenhouse gases. However, unequivocal attribution to human-induced climate change cannot be claimed across all the climate models and uncertainties in our detection procedure, arising out of various sources including the use of models, cannot be ruled out. Changes in solar irradiance and volcanic activities are considered as other plausible natural external causes of climate change. Time evolution of the anthropogenic climate change "signal" in the hydrological observations, above the natural internal climate variability "noise" shows that the detection of the signal is achieved earlier in streamflow as compared to precipitation for most of the climate models, suggesting larger impacts of human-induced climate change on streamflow than precipitation at the river basin scale.

  8. Inter-relationships of MnO 2 precipitation, siderophore-Mn (III) complex formation, siderophore degradation, and iron limitation in Mn (II)-oxidizing bacterial cultures

    NASA Astrophysics Data System (ADS)

    Parker, Dorothy L.; Morita, Takami; Mozafarzadeh, Mylene L.; Verity, Rebecca; McCarthy, James K.; Tebo, Bradley M.

    2007-12-01

    To examine the pathways that form Mn (III) and Mn (IV) in the Mn (II)-oxidizing bacterial strains Pseudomonas putida GB-1 and MnB1, and to test whether the siderophore pyoverdine (PVD) inhibits Mn (IV)O 2 formation, cultures were subjected to various protocols at known concentrations of iron and PVD. Depending on growth conditions, P. putida produced one of two oxidized Mn species - either soluble PVD-Mn (III) complex or insoluble Mn (IV)O 2 minerals - but not both simultaneously. PVD-Mn (III) was present, and MnO 2 precipitation was inhibited, both in iron-limited cultures that had synthesized 26-50 μM PVD and in iron-replete (non-PVD-producing) cultures that were supplemented with 10-550 μM purified PVD. PVD-Mn (III) arose by predominantly ligand-mediated air oxidation of Mn (II) in the presence of PVD, based on the following evidence: (a) yields and rates of this reaction were similar in sterile media and in cultures, and (b) GB-1 mutants deficient in enzymatic Mn oxidation produced PVD-Mn (III) as efficiently as wild type. Only wild type, however, could degrade PVD-Mn (III), a process linked to the production of both MnO 2 and an altered PVD with absorbance and fluorescence spectra markedly different from those of either PVD or PVD-Mn (III). Two conditions, the presence of bioavailable iron and the absence of PVD at concentrations exceeding those of Mn, both had to be satisfied for MnO 2 to appear. These results suggest that P. putida cultures produce soluble Mn (III) or MnO 2 by different and mutually inhibitory pathways: enzymatic catalysis yielding MnO 2 under iron sufficiency or PVD-promoted oxidation yielding PVD-Mn (III) under iron limitation. Since PVD-producing Pseudomonas species are environmentally prevalent Mn oxidizers, these data predict influences of iron (via PVD-Mn (III) versus MnO 2) on the global oxidation/reduction cycling of various pollutants, recalcitrant organic matter, and elements such as C, S, N, Cr, U, and Mn.

  9. Atmospheric Radiation Measurement (ARM) Data from Black Forest Germany for the Convective and Orographically Induced Precipitation Study (COPS)

    DOE Data Explorer

    The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility (AMF) to other sites as determined. In 2007 the AMF operated in the Black Forest region of Germany as part of the Convective and Orographically Induced Precipitation Study (COPS). Scientists studied rainfall resulting from atmospheric uplift (convection) in mountainous terrain, otherwise known as orographic precipitation. This was part of a six -year duration of the German Quantitative Precipitation Forecasting (QPF) Program. COPS was endorsed as a Research and Development Project by the World Weather Research Program. This program was established by the World Meteorological Organization to develop improved and cost-effective forecasting techniques, with an emphasis on high-impact weather. A large collection of data plots based on data streams from specific instruments used at Black Forest are available via a link from ARM's Black Forest site information page. Users will be requested to create a password, but the plots and the data files in the ARM Archive are free for viewing and downloading.

  10. The Convective and Orographically Induced Precipitation Study (COPS): The Scientific Strategy, the Field Phase, and Research Highlights

    SciTech Connect

    Wulfmeyer, Volker; Behrendt, Andreas; Kottmeir, Christoph; Corsmeier, Ulrich; Barthlott, Christian; Craig, George C.; Hagen, Martin; Althausen, Dietrich; Aoshima, Fumiko; Arpagaus, Marco; Bauer, Hans-Stefan; Bennett, Lindsay; Blyth, Alan; Brandau, Christine; Champollion, Cedric; Crewell, Susanne; Dick, Galina; di Girolamo, Paolo; Dorninger, Manfred; Dufournet, Yann; Eigenmann, Rafael; Engelmann, Ronny; Flamant, C.; Foken, Thomas; Gorgas, Theresa; Grzeschik, Matthias; Handwerker, Jan; Hauck, Christian; Holler, Hartmut; Junkermann, W.; Kalthoff, Norbert; Kiemle, Christoph; Klink, Stefan; Konig, Marianne; Krauss, Liane; Long, Charles N.; Madonna, Fabio; Mobbs, S.; Neininger, Bruno; Pal, Sandip; Peters, Gerhard; Pigeon, Gregoire; Richard, Evelyne; Rotach, Mathias W.; Russchenberg, Herman; Schwitalla, Thomas; Smith, Victoria; Steinacker, Reinhold; Trentman, Jorg; Turner, David D.; van Baelen, Joel; Vogt, Siegfried; Volkert, Hans; Weckwerth, Tammy; Wernli, Heini; Wieser, Andreas; Wirth, Martin

    2011-02-24

    Within the frame of the international field campaign COPS (Convective and Orographically-induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. The COPS field phase was performed from 01 June - 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges Mountains, the Rhine valley and the Black Forest Mountains. The collected data set covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase up to their decay. 18 Intensive Operation Periods (IOPs) with 34 operation days and 8 additional Special Observation Periods (SOPs) were performed providing a comprehensive data set covering different forcing conditions. In this paper an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Some highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS provided new insight in key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of QPF by the assimilation of new observations, and in the performance of ensembles of convection permitting models in complex terrain.

  11. Modeling investigation of the stability and irradiation-induced evolution of nanoscale precipitates in advanced structural materials

    SciTech Connect

    Wirth, Brian

    2015-04-08

    Materials used in extremely hostile environment such as nuclear reactors are subject to a high flux of neutron irradiation, and thus vast concentrations of vacancy and interstitial point defects are produced because of collisions of energetic neutrons with host lattice atoms. The fate of these defects depends on various reaction mechanisms which occur immediately following the displacement cascade evolution and during the longer-time kinetically dominated evolution such as annihilation, recombination, clustering or trapping at sinks of vacancies, interstitials and their clusters. The long-range diffusional transport and evolution of point defects and self-defect clusters drive a microstructural and microchemical evolution that are known to produce degradation of mechanical properties including the creep rate, yield strength, ductility, or fracture toughness, and correspondingly affect material serviceability and lifetimes in nuclear applications. Therefore, a detailed understanding of microstructural evolution in materials at different time and length scales is of significant importance. The primary objective of this work is to utilize a hierarchical computational modeling approach i) to evaluate the potential for nanoscale precipitates to enhance point defect recombination rates and thereby the self-healing ability of advanced structural materials, and ii) to evaluate the stability and irradiation-induced evolution of such nanoscale precipitates resulting from enhanced point defect transport to and annihilation at precipitate interfaces. This project will utilize, and as necessary develop, computational materials modeling techniques within a hierarchical computational modeling approach, principally including molecular dynamics, kinetic Monte Carlo and spatially-dependent cluster dynamics modeling, to identify and understand the most important physical processes relevant to promoting the “selfhealing” or radiation resistance in advanced materials containing

  12. Biomineralization of calcium carbonate polymorphs by the bacterial strains isolated from calcareous sites.

    PubMed

    Dhami, Navdeep Kaur; Reddy, M Sudhakara; Mukherjee, Abhijit

    2013-05-01

    Microbially induced calcium carbonate precipitation (MICCP) is a naturally occurring biological process that has various applications in remediation and restoration of a range of building materials. In the present investigation, five ureolytic bacterial isolates capable of inducing calcium carbonate precipitation were isolated from calcareous soils on the basis of production of urease, carbonic anhydrase, extrapolymeric substances, and biofilm. Bacterial isolates were identified as Bacillus megaterium, B. cereus, B. thuringiensis, B. subtilis, and Lysinibacillus fusiformis based on 16S rRNA analysis. The calcium carbonate polymorphs produced by various bacterial isolates were analyzed by scanning electron microscopy, confocal laser scanning microscopy, X ray diffraction, and Fourier transmission infra red spectroscopy. A strainspecific precipitation of calcium carbonate forms was observed from different bacterial isolates. Based on the type of polymorph precipitated, the technology of MICCP can be applied for remediation of various building materials.

  13. The bacterial toxin CNF1 as a tool to induce retinal degeneration reminiscent of retinitis pigmentosa

    PubMed Central

    Guadagni, Viviana; Cerri, Chiara; Piano, Ilaria; Novelli, Elena; Gargini, Claudia; Fiorentini, Carla; Caleo, Matteo; Strettoi, Enrica

    2016-01-01

    Retinitis pigmentosa (RP) comprises a group of inherited pathologies characterized by progressive photoreceptor degeneration. In rodent models of RP, expression of defective genes and retinal degeneration usually manifest during the first weeks of postnatal life, making it difficult to distinguish consequences of primary genetic defects from abnormalities in retinal development. Moreover, mouse eyes are small and not always adequate to test pharmacological and surgical treatments. An inducible paradigm of retinal degeneration potentially extensible to large animals is therefore desirable. Starting from the serendipitous observation that intraocular injections of a Rho GTPase activator, the bacterial toxin Cytotoxic Necrotizing Factor 1 (CNF1), lead to retinal degeneration, we implemented an inducible model recapitulating most of the key features of Retinitis Pigmentosa. The model also unmasks an intrinsic vulnerability of photoreceptors to the mechanism of CNF1 action, indicating still unexplored molecular pathways potentially leading to the death of these cells in inherited forms of retinal degeneration. PMID:27775019

  14. Macrophage activation induced by Brucella DNA suppresses bacterial intracellular replication via enhancing NO production.

    PubMed

    Liu, Ning; Wang, Lin; Sun, Changjiang; Yang, Li; Tang, Bin; Sun, Wanchun; Peng, Qisheng

    2015-12-01

    Brucella DNA can be sensed by TLR9 on endosomal membrane and by cytosolic AIM2-inflammasome to induce proinflammatory cytokine production that contributes to partially activate innate immunity. Additionally, Brucella DNA has been identified to be able to act as a major bacterial component to induce type I IFN. However, the role of Brucella DNA in Brucella intracellular growth remains unknown. Here, we showed that stimulation with Brucella DNA promote macrophage activation in TLR9-dependent manner. Activated macrophages can suppresses wild type Brucella intracellular replication at early stage of infection via enhancing NO production. We also reported that activated macrophage promotes bactericidal function of macrophages infected with VirB-deficient Brucella at the early or late stage of infection. This study uncovers a novel function of Brucella DNA, which can help us further elucidate the mechanism of Brucella intracellular survival.

  15. Expression of bacterial superantigen genes in mice induces localized mononuclear cell inflammatory responses.

    PubMed Central

    Dow, S W; Potter, T A

    1997-01-01

    Bacterial superantigens are potent T cell activators, and superantigen proteins have been injected into mice and other animals to study T cell responses in vivo. When superantigen proteins are injected, however, the T cell stimulatory effects cannot be confined to specific tissues. Therefore, to target superantigen expression to specific tissues, we used gene transfer techniques to express bacterial superantigen genes in mammalian cells in vitro and in tissues in vivo. Murine, human, and canine cells transfected with superantigen genes in vitro all produced superantigen proteins both intracellularly and extracellularly, as assessed by bioassay, immunocytochemistry, and antigen ELISA. Superantigens produced by transfected eukaryotic cells retained their biologic specificity for T cell receptor binding. Intramuscular injection of superantigen plasmid DNA in vivo induced an intense intramuscular mononuclear cell infiltrate, an effect that could not be reproduced by intramuscular injection of superantigen protein. Intradermal and intravenous injection of superantigen DNA induced cutaneous and intrapulmonary mononuclear cell inflammatory responses, respectively. Thus, superantigen genes can be expressed by mammalian cells in vivo. Superantigen gene therapy represents a novel method of targeting localized T cell inflammatory reactions, with potential application to treatment of cancer and certain infectious diseases. PMID:9169491

  16. Changes in equine hindgut bacterial populations during oligofructose-induced laminitis.

    PubMed

    Milinovich, G J; Trott, D J; Burrell, P C; van Eps, A W; Thoefner, M B; Blackall, L L; Al Jassim, R A M; Morton, J M; Pollitt, C C

    2006-05-01

    In the horse, carbohydrate overload is thought to play an integral role in the onset of laminitis by drastically altering the profile of bacterial populations in the hindgut. The objectives of this study were to develop and validate microbial ecology methods to monitor changes in bacterial populations throughout the course of experimentally induced laminitis and to identify the predominant oligofructose-utilizing organisms. Laminitis was induced in five horses by administration of oligofructose. Faecal specimens were collected at 8 h intervals from 72 h before to 72 h after the administration of oligofructose. Hindgut microbiota able to utilize oligofructose were enumerated throughout the course of the experiment using habitat-simulating medium. Isolates were collected and representatives identified by 16S rRNA gene sequencing. The majority of these isolates collected belonged to the genus Streptococcus, 91% of which were identified as being most closely related to Streptococcus infantarius ssp. coli. Furthermore, S. infantarius ssp. coli was the predominant oligofructose-utilizing organism isolated before the onset of lameness. Fluorescence in situ hybridization probes developed to specifically target the isolated Streptococcus spp. demonstrated marked population increases between 8 and 16 h post oligofructose administration. This was followed by a rapid population decline which corresponded with a sharp decline in faecal pH and subsequently lameness at 24-32 h post oligofructose administration. This research suggests that streptococci within the Streptococcus bovis/equinus complex may be involved in the series of events which precede the onset of laminitis in the horse.

  17. Statistical analysis of the relationship between climate-induced maize yield and rainy-season precipitation across Inner Mongolia, North China

    NASA Astrophysics Data System (ADS)

    Huang, Jin; Chen, Xin; Zhou, Limin; Xue, Yan; Lin, Jie

    2016-06-01

    Exploring possible relationships between climate-induced maize yield and rainy-season precipitation under climate change is fundamental to science-based decision for food security in Inner Mongolia Autonomous Region (IMAR). To determine the relationship of maize yield with precipitation variables across IMAR during 1960-2012, we selected 11 precipitation indices of rainy season and divided IMAR into four sub-regions—west, middle, east, and northeast using principal component analysis and K-means clustering methods. Results show that climate-induced maize yield is more sensitive to precipitation variability in the west and middle IMAR. The most important precipitation factor that limits maize yield is moderate precipitation days in these two sub-regions. Moreover, west and middle Inner Mongolia was dominated by decreasing precipitation during the rainy season. Furthermore, the El Niño/La Niña-Southern Oscillation cycle has the significant influence on the rainy-season precipitation in the west and middle IMAR.

  18. Prompt precipitation and energization of relativistic radiation belt electrons induced by ULF oscillations in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Brito, T.; Hudson, M. K.; Kress, B. T.

    2011-12-01

    The energization and loss processes for energetic radiation belt electrons are not yet well understood. Global simulations using magnetohydrodynamics (MHD) model fields as drivers provide a valuable tool to study the dynamics of these ~MeV energetic particles. We use satellite measurements of the solar wind as the boundary condition for the Lyon-Fedder-Mobarry (LFM) 3D MHD code calculation of fields which then drive electrons in a 3D test particle simulation that keeps track of attributes like energy, pitch-angle and L-shell. Wave-particle interaction can cause both energization and pitch-angle scattering loss. Ultra Low Frequency (ULF) waves resolved by the MHD code have been correlated with both enhancement in outer zone radiation belt electron flux1 and modulation of precipitation loss to the atmosphere2. The time scales seen in several studies linking ULF waves with radiation belt flux increases are usually several hours to a few days1,3, but few studies consider the effects of ULF waves in the Pc-4 to Pc-5 range on electron loss to the atmosphere on a time scale of tens of minutes. We investigate such rapid loss, using measured solar wind input to MHD-test particle simulations for a CME-shock event that occurred on January 21, 2005. We focus on mechanisms by which ULF waves, seen both in the simulations and observations, especially ones driven by pressure variations in the solar wind, influence the radiation belts. ULF modulation was seen in precipitation detected by the MINIS balloon campaign measurements of atmospheric Bremsstrahlung from MeV electron precipitation4. We propose a coherent energization and precipitation mechanism due to trapped electron drift resonance with azimuthally propagating poloidal mode ULF waves during the CME-shock compression of the magnetosphere4; depending on the drift phase, some electrons are energized by the azimuthal electric field pulse and some are de-energized in the perpendicular direction causing them to pitch

  19. In Vitro Evaluation of the Risk of Inducing Bacterial Resistance to Disinfection Treatment with Photolysis of Hydrogen Peroxide

    PubMed Central

    Ikai, Hiroyo; Odashima, Yu; Kanno, Taro; Nakamura, Keisuke; Shirato, Midori; Sasaki, Keiichi; Niwano, Yoshimi

    2013-01-01

    The purpose of the present study was to evaluate the risk of inducing bacterial resistance to disinfection treatment with photolysis of H2O2 and comparing this with existing antibacterial agents. We tested seven antibacterial agents, including amoxicillin, cefepime hydrochloride, erythromycin, ofloxacin, clindamycin hydrochloride, ciprofloxacin hydrochloride, and minocycline hydrochloride, as positive controls for validation of the assay protocol. For all of the agents tested, at least one of the four bacterial species (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Streptococcus salivarius) was resistant to these agents by repeated exposure to subinhibitory concentrations of the agents up to 10 times. In contrast, antibacterial activity against any of the bacterial species tested (S. aureus, E. faecalis, E. coli, S. salivarius, Pseudomonas aeruginosa, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans) was not affected by repeated exposure to the disinfection treatment up to 40 times. This finding suggested that the risk of inducing bacterial resistance by disinfection treatment was low. The active ingredient of this disinfection treatment is hydroxyl radicals generated by photolysis of H2O2. Therefore, hydroxyl radicals interact with several cell structures and different metabolic pathways in microbial cells, probably resulting in a lack of development of bacterial resistance. In conclusion, disinfection treatment with photolysis of H2O2 appears to be a potential alternative for existing antimicrobial agents in terms of a low risk of inducing bacterial resistance. PMID:24282582

  20. In vitro evaluation of the risk of inducing bacterial resistance to disinfection treatment with photolysis of hydrogen peroxide.

    PubMed

    Ikai, Hiroyo; Odashima, Yu; Kanno, Taro; Nakamura, Keisuke; Shirato, Midori; Sasaki, Keiichi; Niwano, Yoshimi

    2013-01-01

    The purpose of the present study was to evaluate the risk of inducing bacterial resistance to disinfection treatment with photolysis of H2O2 and comparing this with existing antibacterial agents. We tested seven antibacterial agents, including amoxicillin, cefepime hydrochloride, erythromycin, ofloxacin, clindamycin hydrochloride, ciprofloxacin hydrochloride, and minocycline hydrochloride, as positive controls for validation of the assay protocol. For all of the agents tested, at least one of the four bacterial species (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Streptococcus salivarius) was resistant to these agents by repeated exposure to subinhibitory concentrations of the agents up to 10 times. In contrast, antibacterial activity against any of the bacterial species tested (S. aureus, E. faecalis, E. coli, S. salivarius, Pseudomonas aeruginosa, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans) was not affected by repeated exposure to the disinfection treatment up to 40 times. This finding suggested that the risk of inducing bacterial resistance by disinfection treatment was low. The active ingredient of this disinfection treatment is hydroxyl radicals generated by photolysis of H2O2. Therefore, hydroxyl radicals interact with several cell structures and different metabolic pathways in microbial cells, probably resulting in a lack of development of bacterial resistance. In conclusion, disinfection treatment with photolysis of H2O2 appears to be a potential alternative for existing antimicrobial agents in terms of a low risk of inducing bacterial resistance.

  1. Prediction of precipitation-induced phlebitis: a statistical validation of an in vitro model.

    PubMed

    Johnson, Jennifer L H; He, Yan; Yalkowsky, Samuel H

    2003-08-01

    To avoid phlebitis, new intravenous (IV) parenterals are often screened by injection into animals. This method is not only expensive and time consuming, it is also detrimental to the animals. An alternate method, focusing on precipitation as the cause, uses an in vitro dynamic injection model that requires less money and time and reduces the need for live models. Validation of the dynamic injection apparatus, for predicting mechanical phlebitis, is established. Twenty-one currently marketed IV products were injected into isotonic Sorenson's phosphate buffer flowing at 5 mL/min. The resulting opacities, produced by precipitation, are measured in an ultraviolet flow cell. These opacity data, coupled with literature reports on phlebitis occurrence, were used to generate a logistic regression that indicates the probability of phlebitis given an opacity value measured by the apparatus. Regression results are supported by a receiver operator characteristic curve that establishes the most ideal cut-off opacity value. This opacity value provides the highest combined sensitivity (statistical power) and specificity while minimizing false-positive and false-negative results. Both analyses show that an opacity value of 0.003 best delineates phlebitic and nonphlebitic products. Measures of sensitivity (0.83), specificity (0.93), positive predictive value (0.93), and negative predictive value (0.78) indicate the model's predictive accuracy and reliability. These results support the use of the dynamic model in place of animals for preliminary phlebitis testing of new IV injectables.

  2. Prostatic Inflammation Induces Fibrosis in a Mouse Model of Chronic Bacterial Infection

    PubMed Central

    Wong, Letitia; Hutson, Paul R.; Bushman, Wade

    2014-01-01

    Inflammation of the prostate is strongly correlated with development of lower urinary tract symptoms and several studies have implicated prostatic fibrosis in the pathogenesis of bladder outlet obstruction. It has been postulated that inflammation induces prostatic fibrosis but this relationship has never been tested. Here, we characterized the fibrotic response to inflammation in a mouse model of chronic bacterial-induced prostatic inflammation. Transurethral instillation of the uropathogenic E. coli into C3H/HeOuJ male mice induced persistent prostatic inflammation followed by a significant increase in collagen deposition and hydroxyproline content. This fibrotic response to inflammation was accompanied with an increase in collagen synthesis determined by the incorporation of 3H-hydroxyproline and mRNA expression of several collagen remodeling-associated genes, including Col1a1, Col1a2, Col3a1, Mmp2, Mmp9, and Lox. Correlation analysis revealed a positive correlation of inflammation severity with collagen deposition and immunohistochemical staining revealed that CD45+VIM+ fibrocytes were abundant in inflamed prostates at the time point coinciding with increased collagen synthesis. Furthermore, flow cytometric analysis demonstrated an increased percentage of these CD45+VIM+ fibrocytes among collagen type I expressing cells. These data show–for the first time–that chronic prostatic inflammation induces collagen deposition and implicates fibrocytes in the fibrotic process. PMID:24950301

  3. THE PROTEASOME REGULATES BACTERIAL CpG DNA-INDUCED SIGNALING PATHWAYS IN MURINE MACROPHAGES

    PubMed Central

    Gao, Jian Jun; Shen, Jing; Kolbert, Christopher; Raghavakaimal, Sreekumar; Papasian, Christopher J.; Qureshi, Asaf A.; Vogel, Stefanie N.; Morrison, David C.; Qureshi, Nilofer

    2010-01-01

    Our previous work has provided strong evidence that the proteasome is central to the vast majority of genes induced in mouse macrophages in response to lipopolysaccharide (LPS) stimulation. In the studies presented here, we evaluated the role of the macrophage proteasome in response to a second microbial product CpG DNA (unmethylated bacterial DNA). For these studies, we applied Affymetrix microarray analysis of RNA derived from murine macrophages stimulated with CpG DNA in the presence or absence of proteasome inhibitor, lactacystin. The results of these studies revealed that similar to LPS, a vast majority of those macrophage genes regulated by CpG DNA are also under the control of the proteasome at 4 h. In contrast to LPS stimulation, however, many of these genes were induced much later than 4 h, at 18 h, in response to CpG DNA. Lactacystin treatment of macrophages completely blocked the CpG DNA-induced gene expression of TNF-α and other genes involved in production of inflammatory mediators. These data strongly support the conclusion that, similar to LPS, the macrophage proteasome is a key regulator of CpG DNA-induced signaling pathways. PMID:20160661

  4. Pore-Forming Toxins Induce Macrophage Necroptosis during Acute Bacterial Pneumonia.

    PubMed

    González-Juarbe, Norberto; Gilley, Ryan Paul; Hinojosa, Cecilia Anahí; Bradley, Kelley Margaret; Kamei, Akinobu; Gao, Geli; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

    2015-12-01

    Necroptosis is a highly pro-inflammatory mode of cell death regulated by RIP (or RIPK)1 and RIP3 kinases and mediated by the effector MLKL. We report that diverse bacterial pathogens that produce a pore-forming toxin (PFT) induce necroptosis of macrophages and this can be blocked for protection against Serratia marcescens hemorrhagic pneumonia. Following challenge with S. marcescens, Staphylococcus aureus, Streptococcus pneumoniae, Listeria monocytogenes, uropathogenic Escherichia coli (UPEC), and purified recombinant pneumolysin, macrophages pretreated with inhibitors of RIP1, RIP3, and MLKL were protected against death. Alveolar macrophages in MLKL KO mice were also protected during S. marcescens pneumonia. Inhibition of caspases had no impact on macrophage death and caspase-1 and -3/7 were determined to be inactive following challenge despite the detection of IL-1β in supernatants. Bone marrow-derived macrophages from RIP3 KO, but not caspase-1/11 KO or caspase-3 KO mice, were resistant to PFT-induced death. We explored the mechanisms for PFT-induced necroptosis and determined that loss of ion homeostasis at the plasma membrane, mitochondrial damage, ATP depletion, and the generation of reactive oxygen species were together responsible. Treatment of mice with necrostatin-5, an inhibitor of RIP1; GW806742X, an inhibitor of MLKL; and necrostatin-5 along with co-enzyme Q10 (N5/C10), which enhances ATP production; reduced the severity of S. marcescens pneumonia in a mouse intratracheal challenge model. N5/C10 protected alveolar macrophages, reduced bacterial burden, and lessened hemorrhage in the lungs. We conclude that necroptosis is the major cell death pathway evoked by PFTs in macrophages and the necroptosis pathway can be targeted for disease intervention.

  5. Pore-Forming Toxins Induce Macrophage Necroptosis during Acute Bacterial Pneumonia

    PubMed Central

    González-Juarbe, Norberto; Gilley, Ryan Paul; Hinojosa, Cecilia Anahí; Bradley, Kelley Margaret; Kamei, Akinobu; Gao, Geli; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

    2015-01-01

    Necroptosis is a highly pro-inflammatory mode of cell death regulated by RIP (or RIPK)1 and RIP3 kinases and mediated by the effector MLKL. We report that diverse bacterial pathogens that produce a pore-forming toxin (PFT) induce necroptosis of macrophages and this can be blocked for protection against Serratia marcescens hemorrhagic pneumonia. Following challenge with S. marcescens, Staphylococcus aureus, Streptococcus pneumoniae, Listeria monocytogenes, uropathogenic Escherichia coli (UPEC), and purified recombinant pneumolysin, macrophages pretreated with inhibitors of RIP1, RIP3, and MLKL were protected against death. Alveolar macrophages in MLKL KO mice were also protected during S. marcescens pneumonia. Inhibition of caspases had no impact on macrophage death and caspase-1 and -3/7 were determined to be inactive following challenge despite the detection of IL-1β in supernatants. Bone marrow-derived macrophages from RIP3 KO, but not caspase-1/11 KO or caspase-3 KO mice, were resistant to PFT-induced death. We explored the mechanisms for PFT-induced necroptosis and determined that loss of ion homeostasis at the plasma membrane, mitochondrial damage, ATP depletion, and the generation of reactive oxygen species were together responsible. Treatment of mice with necrostatin-5, an inhibitor of RIP1; GW806742X, an inhibitor of MLKL; and necrostatin-5 along with co-enzyme Q10 (N5/C10), which enhances ATP production; reduced the severity of S. marcescens pneumonia in a mouse intratracheal challenge model. N5/C10 protected alveolar macrophages, reduced bacterial burden, and lessened hemorrhage in the lungs. We conclude that necroptosis is the major cell death pathway evoked by PFTs in macrophages and the necroptosis pathway can be targeted for disease intervention. PMID:26659062

  6. Plant secondary metabolite-induced shifts in bacterial community structure and degradative ability in contaminated soil.

    PubMed

    Uhlik, Ondrej; Musilova, Lucie; Ridl, Jakub; Hroudova, Miluse; Vlcek, Cestmir; Koubek, Jiri; Holeckova, Marcela; Mackova, Martina; Macek, Tomas

    2013-10-01

    The aim of the study was to investigate how selected natural compounds (naringin, caffeic acid, and limonene) induce shifts in both bacterial community structure and degradative activity in long-term polychlorinated biphenyl (PCB)-contaminated soil and how these changes correlate with changes in chlorobiphenyl degradation capacity. In order to address this issue, we have integrated analytical methods of determining PCB degradation with pyrosequencing of 16S rRNA gene tag-encoded amplicons and DNA-stable isotope probing (SIP). Our model system was set in laboratory microcosms with PCB-contaminated soil, which was enriched for 8 weeks with the suspensions of flavonoid naringin, terpene limonene, and phenolic caffeic acid. Our results show that application of selected plant secondary metabolites resulted in bacterial community structure far different from the control one (no natural compound amendment). The community in soil treated with caffeic acid is almost solely represented by Proteobacteria, Acidobacteria, and Verrucomicrobia (together over 99 %). Treatment with naringin resulted in an enrichment of Firmicutes to the exclusion of Acidobacteria and Verrucomicrobia. SIP was applied in order to identify populations actively participating in 4-chlorobiphenyl catabolism. We observed that naringin and limonene in soil foster mainly populations of Hydrogenophaga spp., caffeic acid Burkholderia spp. and Pseudoxanthomonas spp. None of these populations were detected among 4-chlorobiphenyl utilizers in non-amended soil. Similarly, the degradation of individual PCB congeners was influenced by the addition of different plant compounds. Residual content of PCBs was lowest after treating the soil with naringin. Addition of caffeic acid resulted in comparable decrease of total PCBs with non-amended soil; however, higher substituted congeners were more degraded after caffeic acid treatment compared to all other treatments. Finally, it appears that plant secondary metabolites

  7. Subionospheric VLF/LF phase perturbations produced by lightning-whistler induced particle precipitation

    NASA Astrophysics Data System (ADS)

    Inan, U. S.; Carpenter, D. L.; Helliwell, R. A.; Katsufrakis, J. P.

    1985-08-01

    Rapid phase perturbations of subionospherically propagating VLF/LF signals are associated with lightning-generated whistlers which propagate in the magnetosphere. The perturbations, called 'Trimpi events' or 'Trimpi effects' after their discoverer, are attributed to alterations in the earth-ionosphere waveguide caused by localized enhancements in the ionospheric D region. These enhancements are produced by bursts of high-energy electrons which are precipitated out of the earth's radiation belts by the whistler waves. The present paper has the objective to present and discuss new evidence of whistler-associated phase perturbations of subionospheric signals. Events of this type, called phase Trimpi's were first reported by Lohrey and Kaiser (1979). Attention is given to occurrence statistics in terms of the seasonal distribution and hourly rate of events, possible effects on global VLF/LF navigation, and an interpretive model.

  8. Effect of convective disturbances induced by g-jitter on the periodic precipitation of lysozyme.

    PubMed

    Lappa, M; Carotenuto, L

    2003-01-01

    Numerical simulations are carried out to investigate the crystallization process of a protein macromolecular substance under two different conditions: pure diffusive regime and microgravity conditions present on space laboratories. The configuration under investigation consists of a protein reactor and a salt chamber separated by an "interface". The interface is strictly related to the presence of agarose gel in one of the two chambers. Sedimentation and convection under normal gravity conditions are prevented by the use of gel in the protein chamber (pure diffusive regime). Under microgravity conditions periodic time-dependent accelerations (g-jitter) are taken into account. Novel mathematical models are introduced to simulate the complex phenomena related to protein nucleation and further precipitation (or resolution) according to the concentration distribution and in particular to simulate the motion of the crystals due to g-litter in the microgravity environment. The numerical results show that gellified lysozyme (crystals "locked"on the matrix of agarose gel) precipitates to produce "spaced deposits". The crystal formation results modulated in time and in space (Liesegang patterns), due to the non-linear interplay among transport, crystal nucleation and growth. The propagation of the nucleation front is characterized by a wave-like behavior. In microgravity conditions (without gel), g-jitter effects act modifying the phenomena with respect to the on ground gellified configuration. The role played by the direction of the applied sinusoidal acceleration with respect to the imposed concentration gradient (parallel or perpendicular) is investigated. It has a strong influence on the dynamic behaviour of the depletion zones and on the spatial distribution of the crystals. Accordingly the possibility to obtain better crystals for diffraction analyses is discussed.

  9. Precipitants of hepatic encephalopathy induce rapid astrocyte swelling in an oxidative stress dependent manner.

    PubMed

    Lachmann, Vera; Görg, Boris; Bidmon, Hans Jürgen; Keitel, Verena; Häussinger, Dieter

    2013-08-15

    Hepatic encephalopathy (HE) is seen as the clinical manifestation of a low grade cerebral edema with formation of reactive oxygen and nitrogen species (RNOS). Astrocyte swelling is a crucial event and in cultured astrocytes HE-relevant factors almost instantaneously induce the formation of RNOS. However, short term effects of ammonia, inflammatory cytokines and RNOS on the volume of astrocytes and other brain cells as well as the underlying mechanisms are largely unknown, although a pathogenic link between RNOS formation and swelling in HE has been proposed. This issue was addressed in the present study by means of live-cell volume microscopy of brain cells in vitro. Ammonia, diazepam and pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α), interferon-γ, interleukin-1β induced within 20min astrocyte swelling by about 25% accompanied by nuclear swelling of similar magnitude. Astrocyte swelling in response to NH4Cl, TNF-α or diazepam was abolished by the antioxidant epigallocatechin-gallate pointing to an involvement of RNOS. NH4Cl-induced astrocyte swelling was sensitive to inhibition of glutamine synthetase, NADPH oxidase or nitric oxide synthases. In line with a NMDA receptor-, prostanoid- and Ca(2+)-dependence of NH4Cl-induced RNOS formation, Ca(2+) chelation and inhibition of NMDA receptors or cyclooxygenase suppressed NH4Cl-induced astrocyte swelling, whereas the Ca(2+)-ionophore ionomycin, NMDA, glutamate and prostanoids induced rapid astrocyte swelling. NH4Cl also induced swelling of cultured microglia in a glutamine-synthesis dependent way, but had no effect on cell volume of cultured neurons. It is concluded that the pathways which trigger RNOS formation in astrocytes also trigger astrocyte swelling, whereas conversely and as shown previously hypoosmotic astrocyte swelling can induce RNOS formation. This establishes a complex interplay with an auto-amplificatory loop between RNOS formation and astrocyte swelling as an important event in

  10. Effect of dietary antioxidant supplementation (Cuminum cyminum) on bacterial susceptibility of diabetes-induced rats.

    PubMed

    Moubarz, Gehan; Embaby, Mohamed A; Doleib, Nada M; Taha, Mona M

    2016-01-01

    Diabetic patients are at risk of acquiring infections. Chronic low-grade inflammation is an important factor in the pathogenesis of diabetic complication. Diabetes causes generation of reactive oxygen species that increases oxidative stress, which may play a role in the development of complications as immune-deficiency and bacterial infection. The study aimed to investigate the role of a natural antioxidant, cumin, in the improvement of immune functions in diabetes. Diabetes was achieved by interperitoneal injection of streptozotocin (STZ). Bacterial infection was induced by application of Staphylococcus aureus suspension to a wound in the back of rats. The antioxidant was administered for 6 weeks. Results revealed a decrease in blood glucose levels in diabetic rats (p < 0.001), in addition to improving immune functions by decreasing total IgE approaching to the normal control level. Also, inflammatory cytokine (IL-6, IL-1β and TNF) levels, as well as total blood count decreased in diabetic rats as compared to the control group. Thus, cumin may serve as anti-diabetic treatment and may help in attenuating diabetic complications by improving immune functions. Therefore, a medical dietary antioxidant supplementation is important to improve the immune functions in diabetes.

  11. Effect of dietary antioxidant supplementation (Cuminum cyminum) on bacterial susceptibility of diabetes-induced rats

    PubMed Central

    Embaby, Mohamed A.; Doleib, Nada M.; Taha, Mona M.

    2016-01-01

    Diabetic patients are at risk of acquiring infections. Chronic low-grade inflammation is an important factor in the pathogenesis of diabetic complication. Diabetes causes generation of reactive oxygen species that increases oxidative stress, which may play a role in the development of complications as immune-deficiency and bacterial infection. The study aimed to investigate the role of a natural antioxidant, cumin, in the improvement of immune functions in diabetes. Diabetes was achieved by interperitoneal injection of streptozotocin (STZ). Bacterial infection was induced by application of Staphylococcus aureus suspension to a wound in the back of rats. The antioxidant was administered for 6 weeks. Results revealed a decrease in blood glucose levels in diabetic rats (p < 0.001), in addition to improving immune functions by decreasing total IgE approaching to the normal control level. Also, inflammatory cytokine (IL-6, IL-1β and TNF) levels, as well as total blood count decreased in diabetic rats as compared to the control group. Thus, cumin may serve as anti-diabetic treatment and may help in attenuating diabetic complications by improving immune functions. Therefore, a medical dietary antioxidant supplementation is important to improve the immune functions in diabetes. PMID:27536197

  12. A conserved bacterial protein induces pancreatic beta cell expansion during zebrafish development

    PubMed Central

    Hill, Jennifer Hampton; Franzosa, Eric A; Huttenhower, Curtis; Guillemin, Karen

    2016-01-01

    Resident microbes play important roles in the development of the gastrointestinal tract, but their influence on other digestive organs is less well explored. Using the gnotobiotic zebrafish, we discovered that the normal expansion of the pancreatic β cell population during early larval development requires the intestinal microbiota and that specific bacterial members can restore normal β cell numbers. These bacteria share a gene that encodes a previously undescribed protein, named herein BefA (β Cell Expansion Factor A), which is sufficient to induce β cell proliferation in developing zebrafish larvae. Homologs of BefA are present in several human-associated bacterial species, and we show that they have conserved capacity to stimulate β cell proliferation in larval zebrafish. Our findings highlight a role for the microbiota in early pancreatic β cell development and suggest a possible basis for the association between low diversity childhood fecal microbiota and increased diabetes risk. DOI: http://dx.doi.org/10.7554/eLife.20145.001 PMID:27960075

  13. TIR Domain-Containing Adapter-Inducing Beta Interferon (TRIF) Mediates Immunological Memory against Bacterial Pathogens

    PubMed Central

    Kanagavelu, Saravana; Flores, Claudia; Termini, J. M.; Romero, Laura; Riveron, Reldy; Ruiz, Jose; Arditi, Moshe; Schesser, Kurt

    2015-01-01

    Induction of adaptive immunity leads to the establishment of immunological memory; however, how innate immunity regulates memory T cell function remains obscure. Here we show a previously undefined mechanism in which innate and adaptive immunity are linked by TIR domain-containing adapter-inducing beta interferon (TRIF) during establishment and reactivation of memory T cells against Gram-negative enteropathogens. Absence of TRIF in macrophages (Mϕs) but not dendritic cells led to a predominant generation of CD4+ central memory T cells that express IL-17 during enteric bacterial infection in mice. TRIF-dependent type I interferon (IFN) signaling in T cells was essential to Th1 lineage differentiation and reactivation of memory T cells. TRIF activated memory T cells to facilitate local neutrophil influx and enhance bacterial elimination. These results highlight the importance of TRIF as a mediator of the innate and adaptive immune interactions in achieving the protective properties of memory immunity against Gram-negative bacteria and suggest TRIF as a potential therapeutic target. PMID:26351279

  14. TIR Domain-Containing Adapter-Inducing Beta Interferon (TRIF) Mediates Immunological Memory against Bacterial Pathogens.

    PubMed

    Kanagavelu, Saravana; Flores, Claudia; Termini, J M; Romero, Laura; Riveron, Reldy; Ruiz, Jose; Arditi, Moshe; Schesser, Kurt; Fukata, Masayuki

    2015-11-01

    Induction of adaptive immunity leads to the establishment of immunological memory; however, how innate immunity regulates memory T cell function remains obscure. Here we show a previously undefined mechanism in which innate and adaptive immunity are linked by TIR domain-containing adapter-inducing beta interferon (TRIF) during establishment and reactivation of memory T cells against Gram-negative enteropathogens. Absence of TRIF in macrophages (Mϕs) but not dendritic cells led to a predominant generation of CD4(+) central memory T cells that express IL-17 during enteric bacterial infection in mice. TRIF-dependent type I interferon (IFN) signaling in T cells was essential to Th1 lineage differentiation and reactivation of memory T cells. TRIF activated memory T cells to facilitate local neutrophil influx and enhance bacterial elimination. These results highlight the importance of TRIF as a mediator of the innate and adaptive immune interactions in achieving the protective properties of memory immunity against Gram-negative bacteria and suggest TRIF as a potential therapeutic target.

  15. Nods, Nalps and Naip: intracellular regulators of bacterial-induced inflammation.

    PubMed

    Chamaillard, Mathias; Girardin, Stephen E; Viala, Jérôme; Philpott, Dana J

    2003-09-01

    The innate immune system is the most ancestral and ubiquitous system of defence against microbial infection. The microbial sensing proteins involved in innate immunity recognize conserved and often structural components of microorganisms. One class of these pattern-recognition molecules, the Toll-like receptors (TLRs), are involved in detection of microbes in the extracellular compartment whereas a newly discovered family of proteins, the NBS-LRR proteins (for nucleotide-binding site and leucine-rich repeat), are involved in intracellular recognition of microbes and their products. NBS-LRR proteins are characterized by three structural domains: a C-terminal leucine-rich repeat (LRR) domain able to sense a microbial motif, an intermediary nucleotide binding site (NBS) essential for the oligomerization of the molecule that is necessary for the signal transduction induced by different N-terminal effector motifs, such as a pyrin domain (PYD), a caspase-activating and recruitment domain (CARD) or a baculovirus inhibitor of apoptosis protein repeat (BIR) domain. Two of these family members, Nod1 and Nod2, play a role in the regulation of pro-inflammatory pathways through NF-kappaB induced by bacterial ligands. Recently, it was shown that Nod2 recognizes a specific peptidoglycan motif from bacteria, muramyl dipeptide (MDP). A surprising number of human genetic disorders have been linked to NBS-LRR proteins. For example, mutations in Nod2, which render the molecule insensitive to MDP and unable to induce NF-kappaB activation when stimulated, are associated with susceptibility to a chronic intestinal inflammatory disorder, Crohn's disease. Conversely, mutations in the NBS region of Nod2 induce a constitutive activation of NF-kappaB and are responsible for Blau syndrome, another auto-inflammatory disease. Nalp3, which is an NBS-LRR protein with an N-terminal Pyrin domain, is also implicated in rare auto-inflammatory disorders. In conclusion, NBS-LRR molecules appear as a new

  16. The Influence of the Induced Ferrite and Precipitates of Ti-bearing Steel on the Ductility of Continuous Casting Slab

    NASA Astrophysics Data System (ADS)

    Qian, Guoyu; Cheng, Guoguang; Hou, Zibing

    2015-11-01

    In order to investigate the loss of the ductility of Ti-bearing ship plate steel under 1000 °C, where the ductility begins to reduce rapidly, so the hot ductility of Ti-bearing ship plate steel has been obtained using the Gleeble 1500 thermal-mechanical simulator and also the studies about the effect of grain boundary ferrite films and precipitates containing Ti on the ductility has been carried out. The result showed that the TiN particles precipitating at 950 °C with a larger size and smaller volume fraction cannot effectively suppress the occurrence of recrystallization and the ductility still retains at a high level, although R.A. value presents a certain degree of decline compared with 1000 °C. A large number of smaller Ti(C,N) particles precipitate at 900 °C and can induce the formation of a very small amount of fine grain boundary ferrite, which deteriorates the adhesion strength of the grain boundary, so the R.A. value rapidly reduces to less than 50%. When the temperature falls to close Ae3 (827 °C), the amount of the grain boundary ferrite films increase due to the ferrite phase transformation, but the ferrite film thickness becomes more uneven at the same time, which results in the increase of strain concentration and plays a leading role in causing the decrease of ductility, so the R.A. value has been kept less than 40% as the temperature cooling to 800 °C from 850 °C. When the temperature further decreases, the ductility starts to recover due to the increase of average ferrite film thickness to a greater degree which greatly reduces the strain concentration of the grain boundary.

  17. Glutamine deamidation and dysfunction of ubiquitin/NEDD8 induced by a bacterial effector family.

    PubMed

    Cui, Jixin; Yao, Qing; Li, Shan; Ding, Xiaojun; Lu, Qiuhe; Mao, Haibin; Liu, Liping; Zheng, Ning; Chen, She; Shao, Feng

    2010-09-03

    A family of bacterial effectors including Cif homolog from Burkholderia pseudomallei (CHBP) and Cif from Enteropathogenic Escherichia coli (EPEC) adopt a functionally important papain-like hydrolytic fold. We show here that CHBP was a potent inhibitor of the eukaryotic ubiquitination pathway. CHBP acted as a deamidase that specifically and efficiently deamidated Gln40 in ubiquitin and ubiquitin-like protein NEDD8 both in vitro and during Burkholderia infection. Deamidated ubiquitin was impaired in supporting ubiquitin-chain synthesis. Cif selectively deamidated NEDD8, which abolished the activity of neddylated Cullin-RING ubiquitin ligases (CRLs). Ubiquitination and ubiquitin-dependent degradation of multiple CRL substrates were impaired by Cif in EPEC-infected cells. Mutations of substrate-contacting residues in Cif abolished or attenuated EPEC-induced cytopathic phenotypes of cell cycle arrest and actin stress fiber formation.

  18. Identification of in vivo-induced bacterial protein antigens during calf infection with Chlamydia psittaci.

    PubMed

    Kästner, Julia; Saluz, Hans Peter; Hänel, Frank

    2015-05-01

    Chlamydia (C.) psittaci, the causative agent of ornithosis, is an obligate intracellular pathogen with a unique developmental cycle and a high potential for zoonotic transmission. Various mammalian hosts, such as cattle, horse, sheep and man that are in close contact with contaminated birds can get infected (referred to as psittacosis). Since little is known about long-term sequelae of chronic disease and the molecular mechanisms of chlamydial pathogenesis, a key step in understanding the in vivo situation is the identification of C. psittaci infection-associated proteins. For this, we investigated sera of infected calves. Using the immunoscreening approach In Vivo Induced Antigen Technology (IVIAT) including all relevant controls, we focused on C. psittaci proteins, which are induced in vivo during infection. Sera were pooled, extensively adsorbed against in vitro antigens to eliminate false positive results, and used to screen an inducible C. psittaci 02DC15 genomic expression library. Screening and control experiments revealed 19 immunogenic proteins, which are expressed during infection. They are involved in transport and oxidative stress response, heme and folate biosynthesis, DNA replication, recombination and repair, cell envelope, bacterial secretion systems and hypothetical proteins of so far unknown functions. Some of the proteins found may be considered as diagnostic markers or as candidates for the development of vaccines.

  19. Bacterial translocation aggravates CCl4-induced liver cirrhosis by regulating CD4+ T cells in rats

    PubMed Central

    Shi, Haiyan; Lv, Longxian; Cao, Hongcui; Lu, Haifeng; Zhou, Ning; Yang, Jiezuan; Jiang, Haiyin; Dong, Huihui; Hu, Xinjun; Yu, Wei; Jiang, Xiawei; Zheng, Beiwen; Li, Lanjuan

    2017-01-01

    Bacterial translocation (BT) is thought to play an important role in the development of liver cirrhosis, but the mechanisms have not been fully explored. This study aims to investigate the distribution of Treg (CD3+CD4+CD25+Foxp3+), Th17 (CD3+CD4+IL-17+), and Th1 (CD3+CD4+IFN-γ+) cells in the intestinal lamina propria, liver and blood and to explore their relationships with BT. Cirrhotic rats with ascites were induced by CCl4. We found that there were lower levels of total protein and albumin, lower albumin/globulin ratio, lower body weight and higher spleen weight and ascites volume in cirrhotic rats with than without BT. We found that BT may cause increase of Treg cells in the proximal small intestine and decrease of Th17 cells in the whole intestine and blood in cirrhotic rats. It may also aggravate the CCl4-induced decrease in Th1 cells in the whole intestine, liver, caecum, and blood and the CCl4-induced increase in Th17 cells in the liver and Tregs in the distal small intestine, colon, and liver. Our data suggest that BT may aggravate liver injury and decrease liver function via an interaction with CD4+ T Cells. The results of this study may be helpful for the development of new treatments for liver cirrhosis. PMID:28134306

  20. Early enhanced local neutrophil recruitment in peritonitis-induced sepsis improves bacterial clearance and survival.

    PubMed

    Craciun, Florin L; Schuller, Elizabeth R; Remick, Daniel G

    2010-12-01

    Neutrophils are critical for the rapid eradication of bacterial pathogens, but they also contribute to the development of multiple organ failure in sepsis. We hypothesized that increasing early recruitment of neutrophils to the focus of infection will increase bacterial clearance and improve survival. Sepsis was induced in mice, using cecal ligation and puncture (CLP); blood samples were collected at 6 and 24 h; and survival was followed for 28 d. In separate experiments, peritoneal bacteria and inflammatory cells were measured. Septic mice predicted to die based on IL-6 levels (Die-P) had higher concentrations of CXCL1 and CXCL2 in the peritoneum and plasma compared with those predicted to live (Live-P). At 6 h, Live-P and Die-P had equivalent numbers of peritoneal neutrophils and bacteria. In Die-P mice the number of peritoneal bacteria increased between 6 and 24 h post-CLP, whereas in Live-P it decreased. The i.p. injection of CXCL1 and CXCL2 in naive mice resulted in local neutrophil recruitment. When given immediately after CLP, CXC chemokines increased peritoneal neutrophil recruitment at 6 h after CLP. This early increase in neutrophils induced by exogenous chemokines resulted in significantly fewer peritoneal bacteria by 24 h [CFU (log) = 6.04 versus 4.99 for vehicle versus chemokine treatment; p < 0.05]. Chemokine treatment significantly improved survival at both 5 d (40 versus 72%) and 28 d (27 versus 52%; p < 0.02 vehicle versus chemokines). These data demonstrate that early, local treatment with CXC chemokines enhances neutrophil recruitment and clearance of bacteria as well as improves survival in the CLP model of sepsis.

  1. Raman Lidar Observations of a MCS in the frame of the Convective and Orographically-induced Precipitation Study

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Bhawar, Rohini; Summa, Donato; Di Iorio, Tatiana; Demoz, Belay B.

    2009-03-01

    The Raman lidar system BASIL was deployed in Achern (Supersite R, Lat: 48.64° N, Long: 8.06° E, Elev.: 140 m) in the frame of the Convective and Orographically-induced Precipitation Study. On 20 July 2007 a frontal zone passed over the COPS region, with a Mesoscale Convective System (MCS) imbedded in it. BASIL was operated continuously during this day, providing measurements of temperature, water vapour, particle backscattering coefficient at 355, 532 and 1064 nm, particle extinction coefficient at 355 and 532 nm and particle depolarization at 355 and 532 nm. The thunderstorm approaching determined the lowering of the anvil clouds, which is clearly visible in the lidar data. A cloud deck is present at 2 km, which represents a mid-level outflow from the thunderstorm/MCS. The mid-level outflow spits out hydrometeor-debris (mostly virga) and it is recycled back into it. The MCS modified the environment at 1.6-2.5 km levels directly (outflow) and the lower levels through the virga/precipitation. Wave structures were observed in the particle backscatter data. The wave activity seems to be a reflection of the shear that is produced by the MCS and the inflow environmental wind. Measurements in terms of particle backscatter and water vapour mixing ratio are discussed to illustrate the above phenomena.

  2. Petrographic and geochemical evidence for the formation of primary, bacterially induced lacustrine dolomite: La Roda 'white earth' (Pliocene, Central Spain)

    USGS Publications Warehouse

    Garcia, Del; Cura, M.A.; Calvo, J.P.; Ordonez, S.; Jones, B.F.; Canaveras, J.C.

    2001-01-01

    Upper Pliocene dolomites ('white earth') from La Roda, Spain, offer a good opportunity to evaluate the process of dolomite formation in lakes. The relatively young nature of the deposits could allow a link between dolomites precipitated in modern lake systems and those present in older lacustrine formations. The La Roda Mg-carbonates (dolomite unit) occur as a 3??5- to 4-m- thick package of poorly indurated, white, massive dolomite beds with interbedded thin deposits of porous carbonate displaying root and desiccation traces as well as local lenticular gypsum moulds. The massive dolomite beds consist mainly of loosely packed 1- to 2-??m-sized aggregates of dolomite crystals exhibiting poorly developed faces, which usually results in a subrounded morphology of the crystals. Minute rhombs of dolomite are sparse within the aggregates. Both knobbly textures and clumps of spherical bodies covering the crystal surfaces indicate that bacteria were involved in the formation of the dolomites. In addition, aggregates of euhedral dolomite crystals are usually present in some more clayey (sepiolite) interbeds. The thin porous carbonate (mostly dolomite) beds exhibit both euhedral and subrounded, bacterially induced dolomite crystals. The carbonate is mainly Ca-dolomite (51-54 mol% CaCO3), showing a low degree of ordering (degree of ordering ranges from 0??27 to 0??48). Calcite is present as a subordinate mineral in some samples. Sr, Mn and Fe contents show very low correlation coefficients with Mg/Ca ratios, whereas SiO2 and K contents are highly correlated. ??18O- and ??13C-values in dolomites range from -3??07??? to 5??40??? PDB (mean = 0??06, ?? = 1??75) and from -6??34??? to -0??39??? PDB (mean = -3??55, ?? = 1??33) respectively. Samples containing significant amounts of both dolomite and calcite do not in general show significant enrichment or depletion in 18O and 13C between the two minerals. The correlation coefficient between ??18O and ??13C for dolomite is extremely

  3. Lidar and Radar Measurements of the melting layer in the frame of the Convective and Orographically-induced Precipitation Study

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Summa, Donato; Bhawar, Rohini; Di Iorio, Tatiana; Vaughan, Geraint; Norton, Emily; Peters, Gerhard

    2009-03-01

    During the Convective and Orographically-induced Precipitation Study (COPS), lidar dark bands were observed by the Univ. of BASILicata Raman lidar system (BASIL) on several IOPs and SOPs (among others, 23 July, 15 August, 17 August). Dark band signatures appear in the lidar measurements of particle backscattering at 355, 532 and 1064 nm and particle extinction at 355 and 532 nm, as well as in particle depolarization measurements. Lidar data are supported by measurements from the University of Hamburg cloud radar MIRA 36 (36 GHz), the University of Hamburg dual-polarization micro rain radars (24.1 GHz) and the University of Manchester Radio UHF clear air wind profiler (1.29 GHz). Results from BASIL and the radars are illustrated and discussed to support in the comprehension of the microphysical and scattering processes responsible for the appearance of the lidar dark band and radar bright band.

  4. Hippocampal microglial activation and glucocorticoid receptor down-regulation precipitate visceral hypersensitivity induced by colorectal distension in rats.

    PubMed

    Zhang, Gongliang; Zhao, Bing-Xue; Hua, Rong; Kang, Jie; Shao, Bo-Ming; Carbonaro, Theresa M; Zhang, Yong-Mei

    2016-03-01

    Visceral hypersensitivity is a common characteristic in patients suffering from irritable bowel syndrome (IBS) and other disorders with visceral pain. Although the pathogenesis of visceral hypersensitivity remains speculative due to the absence of pathological changes, the long-lasting sensitization in neuronal circuitry induced by early life stress may play a critical role beyond the digestive system even after complete resolution of the initiating event. The hippocampus integrates multiple sources of afferent inputs and sculpts integrated autonomic outputs for pain and analgesia regulation. Here, we examined the hippocampal mechanism in the pathogenesis of visceral hypersensitivity with a rat model induced by neonatal and adult colorectal distensions (CRDs). Neither neonatal nor adult CRD evoked behavioral abnormalities in adulthood; however, adult re-exposure to CRD induced persistent visceral hypersensitivity, depression-like behaviors, and spatial learning impairment in rats that experienced neonatal CRD. Rats that experienced neonatal and adult CRDs presented a decrease in hippocampal glucocorticoid receptor (GR) immunofluorescence staining and protein expression, and increases in hippocampal microglial activation and cytokine (IL-1β and TNF-α) accumulation. The decrease in hippocampal GR expression and increase in hippocampal IL-1β and TNF-α accumulation could be prevented by hippocampal local infusion of minocycline, a microglial inhibitor. These results suggest that neonatal CRD can increase the vulnerability of hippocampal microglia, and adult CRD challenge facilitates the hippocampal cytokine release from the sensitized microglia, which down-regulates hippocampal GR protein expression and, subsequently, precipitates visceral hypersensitivity.

  5. Microbially induced carbonate precipitation (MICP) by denitrification as ground improvement method - Process control in sand column experiments

    NASA Astrophysics Data System (ADS)

    Pham, Vinh; van Paassen, Leon; Nakano, Akiko; Kanayama, Motohei; Heimovaara, Timo

    2013-04-01

    Calcite precipitation induced by microbes has been proven to be efficient in stabilizing granular soils, especially with urea hydrolysis, as it has been successfully demonstrated in a pilot application 2010. However, as a byproduct highly concentrated ammonium chloride (NH4Cl) solution is produced, which has to be removed and disposed and forms a significant disadvantage of the technique that makes an alternative process like denitrification preferred. The proof of principle of microbially induced calcite precipitation (MICP) by denitrification has been demonstrated by Van Paassen et al (2010) who suggested that instead of producing waste as a byproduct, different pre-treated waste streams could be used as substrates for in situ growth of denitrifying bacteria and simultaneous cementation without producing waste to be removed. In this study sand column experiments are performed in which calcium carbonate was successfully precipitated by indigenous denitrifying micro-organisms, which were supplied weekly with a pulse of a substrate solution containing calcium acetate and calcium nitrate. Besides the production of calcite and the growth of bacteria in biofilms, the reduction of nitrate resulted in the production of (nitrogen) gas. It was observed that this gas partly fills up the pore space and consequently contributed to a reduction of the permeability of the treated sand. The presence of gas in the pore space affected the flow of the injected substrates and influenced to the distribution of calcium carbonate. The effect of the mean particle size (D50) on the flow and transport of solutes and gas in the porous media has been evaluated by treating several columns with varying grain size distribution and comparing the change in permeability after each incubation period and analyzing the distribution of the gas throughout the columns using X-ray computed tomography (CT) scanning. The present results show that there is a considerable decrease of permeability - a

  6. Transcriptome analysis of a bacterially induced basal and hypersensitive response of Medicago truncatula.

    PubMed

    Bozsó, Zoltán; Maunoury, Nicolas; Szatmari, Agnes; Mergaert, Peter; Ott, Péter G; Zsíros, László R; Szabó, Erika; Kondorosi, Eva; Klement, Zoltán

    2009-08-01

    Research using the well-studied model legume Medicago truncatula has largely focused on rhizobium symbiosis, while little information is currently available for this species on pathogen-induced transcriptome changes. We have performed a transcriptome analysis of this species with the objective of studying the basal (BR, no visible symptoms) and hypersensitive response (HR, plant cell death) in its leaves at 6 and at 24 h after infection by HR-negative (hrcC mutant) and HR-inducing Pseudomonas syringae pv. syringae strains, respectively. Although there were no visible symptoms at the BR, the alterations in gene expression were comparable to those found with the HR. Both responses resulted in the transcriptional alteration of hundreds of plant genes; however, the responses in the HR were usually more intense. The reactions to HR-inducing and HR-negative bacterial strains were significantly overlapping. Parallel up- or down-regulation of genes with the same function occurred frequently. However, some plant processes were regulated in one direction; for example, most of the protein synthesis-related genes were activated and all of the photosynthetic/chloroplast genes were suppressed during BR. The possible roles of several functional classes (e.g., cell rescue, signaling, defense, cell death, etc.) of transcriptionally altered genes are discussed. The results of the comparison with available mycorrhizal and nodule expression data show that there is a significant overlap between nodulation and the leaf defense response and that during the early stage of the nodulation in roots, Sinorhizobium meliloti induces a fluctuation in the transcription of BR- and HR-responsive genes.

  7. Local decomposition induced by dislocation motions inside precipitates in an Al-alloy

    PubMed Central

    Yang, B.; Zhou, Y. T.; Chen, D.; Ma, X. L.

    2013-01-01

    Dislocations in crystals are linear crystallographic defects, which move in lattice when crystals are plastically deformed. Motion of a partial dislocation may remove or create stacking fault characterized with a partial of a lattice translation vector. Here we report that motion of partial dislocations inside an intermetallic compound result in a local composition deviation from its stoichiometric ratio, which cannot be depicted with any vectors of the primary crystal. Along dislocation slip bands inside the deformed Al2Cu particles, redistribution of Cu and Al atoms leads to a local decomposition and collapse of the original crystal structure. This finding demonstrates that dislocation slip may induce destabilization in complex compounds, which is fundamentally different from that in monometallic crystals. This phenomenon of chemical unmixing of initially homogeneous multicomponent solids induced by dislocation motion might also have important implications for understanding the geologic evolvement of deep-focus peridotites in the Earth. PMID:23301160

  8. Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

    SciTech Connect

    Jacobs, G.P.; Samuni, A.; Czapski, G.

    1980-01-01

    Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous.

  9. [Advances in molecular mechanisms of bacterial resistance caused by stress-induced transfer of resistance genes--a review].

    PubMed

    Sun, Dongchang; Wang, Bing; Zhu, Lihong

    2013-07-04

    The transfer of resistance gene is one of the most important causes of bacterial resistance. Recent studies reveal that stresses induce the transfer of antibiotic resistance gene through multiple mechanisms. DNA damage stresses trigger bacterial SOS response and induce the transfer of resistance gene mediated by conjugative DNA. Antibiotic stresses induce natural bacterial competence for transformation in some bacteria which lack the SOS system. In addition, our latest studies show that the general stress response regulator RpoS regulates a novel type of resistance gene transfer which is mediated by double-stranded plasmid DNA and occurs exclusively on the solid surface. In this review, we summarized recent advances in SOS dependent and independent stress-induced DNA transfer which is mediated by conjugation and transformation respectively, and the transfer of double-stranded plasmid DNA on the solid surface which is regulated by RpoS. We propose that future work should address how stresses activate the key regulators and how these regulators control the expression of gene transfer related genes. Answers to the above questions would pave the way for searching for candidate targets for controlling bacterial resistance resulted from the transfer of antibiotic genes.

  10. Piezoelectric quartz crystal impedance study of the Pb2+-induced precipitation of bovine serum albumin and its dissolution with EDTA in an aqueous solution.

    PubMed

    Yuan, Yu; Cai, Yan; Xie, Qingji; Yao, Shouzhuo

    2002-07-01

    The piezoelectric quartz crystal impedance technique (QCI) was employed to monitor in situ the Pb2+-induced precipitation of BSA onto a gold electrode and the precipitate dissolution with EDTA in an aqueous solution. The critical precipitation concentration of Pb2+, at which the resonant frequency decreased significantly, was estimated to be 4.78 x 10(-4) mol/L. The saturated adherence of the precipitate on the electrode was observed when the concentration of Pb2+ was greater than 7.53 x 10(-2) mol/L. The frequency response was mainly caused by the mass effect of the precipitate adherence to the electrode, rather than the changes in the physico-chemical properties of the contacting liquid. An excess addition of Na2EDTA after the Pb2+-BSA dissolution led to new precipitation, probably due to the formation of an EDTA precipitate in this medium (pH approximately 3). The pH effect on the response of the resonant frequency was analyzed by using the sum of two exponential functions. A larger frequency response occurred at a pH greater than pI. These findings have been reasonably explained. Also, a decrease in the concentration of the background electrolyte increased the frequency response.

  11. Ralstonia solanacearum lipopeptide induces chlamydospore development in fungi and facilitates bacterial entry into fungal tissues

    PubMed Central

    Spraker, Joseph E; Sanchez, Laura M; Lowe, Tiffany M; Dorrestein, Pieter C; Keller, Nancy P

    2016-01-01

    Ralstonia solanacearum is a globally distributed soil-borne plant pathogenic bacterium, which shares a broad ecological range with many plant- and soil-associated fungi. We sought to determine if R. solanacearum chemical communication directs symbiotic development of polymicrobial consortia. R. solanacearum produced a diffusible metabolite that induced conserved morphological differentiation in 34 species of fungi across three diverse taxa (Ascomycetes, Basidiomycetes and Zygomycetes). Fungi exposed to this metabolite formed chlamydospores, survival structures with thickened cell walls. Some chlamydospores internally harbored R. solanacearum, indicating a newly described endofungal lifestyle for this important plant pathogen. Using imaging mass spectrometry and peptidogenomics, we identified an undescribed lipopeptide, ralsolamycin, produced by an R. solanacearum non-ribosomal peptide synthetase-polyketide synthase hybrid. Inactivation of the hybrid non-ribosomal peptide synthetase-polyketide synthase gene, rmyA, abolished ralsolamycin synthesis. R. solanacearum mutants lacking ralsolamycin no longer induced chlamydospore development in fungal coculture and invaded fungal hyphae less well than wild-type. We propose that ralsolamycin contributes to the invasion of fungal hyphae and that the formation of chlamydospores may provide not only a specific niche for bacterial colonization but also enhanced survival for the partnering fungus. PMID:26943626

  12. A Bacterial Quorum-Sensing Precursor Induces Mortality in the Marine Coccolithophore, Emiliania huxleyi

    PubMed Central

    Harvey, Elizabeth L.; Deering, Robert W.; Rowley, David C.; El Gamal, Abrahim; Schorn, Michelle; Moore, Bradley S.; Johnson, Matthew D.; Mincer, Tracy J.; Whalen, Kristen E.

    2016-01-01

    Interactions between phytoplankton and bacteria play a central role in mediating biogeochemical cycling and food web structure in the ocean. However, deciphering the chemical drivers of these interspecies interactions remains challenging. Here, we report the isolation of 2-heptyl-4-quinolone (HHQ), released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria previously reported to induce phytoplankton mortality through a hitherto unknown algicidal mechanism. HHQ functions as both an antibiotic and a bacterial signaling molecule in cell–cell communication in clinical infection models. Co-culture of the bloom-forming coccolithophore, Emiliania huxleyi with both live P. piscicida and cell-free filtrates caused a significant decrease in algal growth. Investigations of the P. piscicida exometabolome revealed HHQ, at nanomolar concentrations, induced mortality in three strains of E. huxleyi. Mortality of E. huxleyi in response to HHQ occurred slowly, implying static growth rather than a singular loss event (e.g., rapid cell lysis). In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures. These results suggest that HHQ mediates the type of inter-domain interactions that cause shifts in phytoplankton population dynamics. These chemically mediated interactions, and other like it, ultimately influence large-scale oceanographic processes. PMID:26870019

  13. Midgut immune responses induced by bacterial infection in the silkworm, Bombyx mori *

    PubMed Central

    ZHANG, Lei; WANG, Yan-wen; LU, Zhi-qiang

    2015-01-01

    Insect gut epithelial cells produce reactive oxygen species (ROS) and antimicrobial peptides (AMPs) to protect hosts from pathogenic microorganisms. In this study, we evaluate the pathogenicity of Pseudomonas aeruginosa and Bacillus bombysepticus in the silkworm, Bombyx mori. Survival curves show that B. bombysepticus is deadly when larval silkworms are infected orally. Bacterial infection caused intestinal hydrogen peroxide (H2O2) and nitric oxide (NO) levels to increase significantly by 8 and 16 h post-infection (hpi), respectively. Real-time quantitative polymerase chain reaction (qPCR) analysis shows that the transcription levels of dual oxidase (Duox) and catalase (CAT) are highly up-regulated by P. aeruginosa infection at 8 hpi. P. aeruginosa infection induced nitric oxide synthase 2 (NOS2) expression at 16 hpi, which contributes to the generation of NO. mRNA levels of AMP genes, specifically Glovorin 2 and Glovorin 3, which obviously increase during the early infection stage. These results indicate that invading bacteria elevate intestinal ROS and NO levels and induce AMP gene transcription, which contributes to intestinal immune defense. PMID:26465135

  14. A new cytogenetic mechanism for bacterial endosymbiont-induced parthenogenesis in Hymenoptera.

    PubMed

    Adachi-Hagimori, Tetsuya; Miura, Kazuki; Stouthamer, Richard

    2008-12-07

    Vertically transmitted endosymbiotic bacteria, such as Wolbachia, Cardinium and Rickettsia, modify host reproduction in several ways to facilitate their own spread. One such modification results in parthenogenesis induction, where males, which are unable to transmit the bacteria, are not produced. In Hymenoptera, the mechanism of diploidization due to Wolbachia infection, known as gamete duplication, is a post-meiotic modification. During gamete duplication, the meiotic mechanism is normal, but in the first mitosis the anaphase is aborted. The two haploid sets of chromosomes do not separate and thus result in a single nucleus containing two identical sets of haploid chromosomes. Here, we outline an alternative cytogenetic mechanism for bacterial endosymbiont-induced parthenogenesis in Hymenoptera. During female gamete formation in Rickettsia-infected Neochrysocharis formosa (Westwood) parasitoids, meiotic cells undergo only a single equational division followed by the expulsion of a single polar body. This absence of meiotic recombination and reduction corresponds well with a non-segregation pattern in the offspring of heterozygous females. We conclude that diploidy in N. formosa is maintained through a functionally apomictic cloning mechanism that differs entirely from the mechanism induced by Wolbachia.

  15. No long-term persistence of bacterial pollution-induced community tolerance in tylosin-polluted soil.

    PubMed

    Demoling, Louise Aldén; Bååth, Erland

    2008-09-15

    Pollution-induced community tolerance (PICT) of soil bacteria to the antibiotic tylosin was studied over 95 days. Tylosin was added at increasing concentrations, together with different amounts of alfalfa to study the effects of substrate addition on PICT and bacterial growth in soil. The leucine incorporation technique was used to estimate bacterial growth and as a detection method in the PICT concept. Direct inhibition of the bacterial growth rates, resulting in a dose-response curve, was found above 50 mg of tylosin kg(-1) of soil two days after tylosin addition (IC50 value of 960 mg tylosin kg(-1)). After 10 days of exposure to at least 50 mg of tylosin kg(-1), the PICT was observed and correlated to inhibition of bacterial growth by tylosin. A return of the PICT to control levels was found over time, and after 95 days at 1500 mg of tylosin kg(-1), essentially no PICT was found, as compared to the unpolluted control soil. The return of PICT to pre-exposure levels was not totally reflected in the recovery of bacterial growth. Alfalfa addition did not affect the inhibitory effect of tylosin on bacterial growth rates; neither did it alter the PICT. Since tylosin is relatively rapidly degraded in soil, our results indicate that the PICT will return to prepollution levels when the selective pressure of the toxicant is removed and will thus be a useful technique for monitoring remediation measures.

  16. Pathogen-induced conditioning of the primary xylem vessels - a prerequisite for the formation of bacterial emboli by Pectobacterium atrosepticum.

    PubMed

    Gorshkov, V Y; Daminova, A G; Mikshina, P V; Petrova, O E; Ageeva, M V; Salnikov, V V; Gorshkova, T A; Gogolev, Y V

    2016-07-01

    Representatives of Pectobacterium genus are some of the most harmful phytopathogens in the world. In the present study, we have elucidated novel aspects of plant-Pectobacterium atrosepticum interactions. This bacterium was recently demonstrated to form specific 'multicellular' structures - bacterial emboli in the xylem vessels of infected plants. In our work, we showed that the process of formation of these structures includes the pathogen-induced reactions of the plant. The colonisation of the plant by P. atrosepticum is coupled with the release of a pectic polysaccharide, rhamnogalacturonan I, into the vessel lumen from the plant cell wall. This polysaccharide gives rise to a gel that serves as a matrix for bacterial emboli. P. atrosepticum-caused infection involves an increase of reactive oxygen species (ROS) levels in the vessels, creating the conditions for the scission of polysaccharides and modification of plant cell wall composition. Both the release of rhamnogalacturonan I and the increase in ROS precede colonisation of the vessels by bacteria and occur only in the primary xylem vessels, the same as the subsequent formation of bacterial emboli. Since the appearance of rhamnogalacturonan I and increase in ROS levels do not hamper the bacterial cells and form a basis for the assembly of bacterial emboli, these reactions may be regarded as part of the susceptible response of the plant. Bacterial emboli thus represent the products of host-pathogen integration, since the formation of these structures requires the action of both partners.

  17. Streptococcus oralis Induces Lysosomal Impairment of Macrophages via Bacterial Hydrogen Peroxide

    PubMed Central

    Okahashi, Nobuo; Kuwata, Hirotaka; Kawabata, Shigetada

    2016-01-01

    Streptococcus oralis, an oral commensal, belongs to the mitis group of streptococci and occasionally causes opportunistic infections, such as bacterial endocarditis and bacteremia. Recently, we found that the hydrogen peroxide (H2O2) produced by S. oralis is sufficient to kill human monocytes and epithelial cells, implying that streptococcal H2O2 is a cytotoxin. In the present study, we investigated whether streptococcal H2O2 impacts lysosomes, organelles of the intracellular digestive system, in relation to cell death. S. oralis infection induced the death of RAW 264 macrophages in an H2O2-dependent manner, which was exemplified by the fact that exogenous H2O2 also induced cell death. Infection with either a mutant lacking spxB, which encodes pyruvate oxidase responsible for H2O2 production, or Streptococcus mutans, which does not produce H2O2, showed less cytotoxicity. Visualization of lysosomes with LysoTracker revealed lysosome deacidification after infection with S. oralis or exposure to H2O2, which was corroborated by acridine orange staining. Similarly, fluorescent labeling of lysosome-associated membrane protein-1 gradually disappeared during infection with S. oralis or exposure to H2O2. The deacidification and the following induction of cell death were inhibited by chelating iron in lysosomes. Moreover, fluorescent staining of cathepsin B indicated lysosomal destruction. However, treatment of infected cells with a specific inhibitor of cathepsin B had negligible effects on cell death; instead, it suppressed the detachment of dead cells from the culture plates. These results suggest that streptococcal H2O2 induces cell death with lysosomal destruction and then the released lysosomal cathepsins contribute to the detachment of the dead cells. PMID:27113357

  18. Soil bacterial community structure remains stable over a 5-year chronosequence of insect-induced tree mortality.

    PubMed

    Ferrenberg, Scott; Knelman, Joseph E; Jones, Jennifer M; Beals, Stower C; Bowman, William D; Nemergut, Diana R

    2014-01-01

    Extensive tree mortality from insect epidemics has raised concern over possible effects on soil biogeochemical processes. Yet despite the importance of microbes in nutrient cycling, how soil bacterial communities respond to insect-induced tree mortality is largely unknown. We examined soil bacterial community structure (via 16S rRNA gene pyrosequencing) and community assembly processes (via null deviation analysis) along a 5-year chronosequence (substituting space for time) of bark beetle-induced tree mortality in the southern Rocky Mountains, USA. We also measured microbial biomass and soil chemistry, and used in situ experiments to assess inorganic nitrogen mineralization rates. We found that bacterial community structure and assembly-which was strongly influenced by stochastic processes-were largely unaffected by tree mortality despite increased soil ammonium ([Formula: see text]) pools and reductions in soil nitrate ([Formula: see text]) pools and net nitrogen mineralization rates after tree mortality. Linear models suggested that microbial biomass and bacterial phylogenetic diversity are significantly correlated with nitrogen mineralization rates of this forested ecosystem. However, given the overall resistance of the bacterial community to disturbance from tree mortality, soil nitrogen processes likely remained relatively stable following tree mortality when considered at larger spatial and longer temporal scales-a supposition supported by the majority of available studies regarding biogeochemical effects of bark beetle infestations in this region. Our results suggest that soil bacterial community resistance to disturbance helps to explain the relatively weak effects of insect-induced tree mortality on soil N and C pools reported across the Rocky Mountains, USA.

  19. Soil bacterial community structure remains stable over a 5-year chronosequence of insect-induced tree mortality

    PubMed Central

    Ferrenberg, Scott; Knelman, Joseph E.; Jones, Jennifer M.; Beals, Stower C.; Bowman, William D.; Nemergut, Diana R.

    2014-01-01

    Extensive tree mortality from insect epidemics has raised concern over possible effects on soil biogeochemical processes. Yet despite the importance of microbes in nutrient cycling, how soil bacterial communities respond to insect-induced tree mortality is largely unknown. We examined soil bacterial community structure (via 16S rRNA gene pyrosequencing) and community assembly processes (via null deviation analysis) along a 5-year chronosequence (substituting space for time) of bark beetle-induced tree mortality in the southern Rocky Mountains, USA. We also measured microbial biomass and soil chemistry, and used in situ experiments to assess inorganic nitrogen mineralization rates. We found that bacterial community structure and assembly—which was strongly influenced by stochastic processes—were largely unaffected by tree mortality despite increased soil ammonium (NH4+) pools and reductions in soil nitrate (NO3−) pools and net nitrogen mineralization rates after tree mortality. Linear models suggested that microbial biomass and bacterial phylogenetic diversity are significantly correlated with nitrogen mineralization rates of this forested ecosystem. However, given the overall resistance of the bacterial community to disturbance from tree mortality, soil nitrogen processes likely remained relatively stable following tree mortality when considered at larger spatial and longer temporal scales—a supposition supported by the majority of available studies regarding biogeochemical effects of bark beetle infestations in this region. Our results suggest that soil bacterial community resistance to disturbance helps to explain the relatively weak effects of insect-induced tree mortality on soil N and C pools reported across the Rocky Mountains, USA. PMID:25566204

  20. Microbially Induced Calcite Precipitation (MICP) - A Technology for Managing Flow and Transport in Porous and Fractured Media

    NASA Astrophysics Data System (ADS)

    Phillips, A. J.; Hiebert, R.; Kirksey, J.; Lauchnor, E. G.; Rothman, A.; Spangler, L.; Esposito, R.; Gerlach, R.; Cunningham, A. B.

    2014-12-01

    Certain microorganisms e.g., Sporosarcina pasteurii contribute enzymes that catalyze reactions which in the presence of calcium, can create saturation conditions favorable for calcium carbonate precipitation (microbially-induced calcium carbonate precipitation (MICP)). MICP can be used for a number of engineering applications including securing geologic storage of CO2 or other fluids by sealing fractures, improving wellbore integrity, and stabilizing fractured and unstable porous media. MICP treatment has the advantage of the use of small microorganisms, ~2μm, suggesting applicability to treatment of small aperture fractures not accessible to traditional treatments, for example the use of fine cement. The promotion of MICP in the subsurface is a complex reactive transport problem coupling microbial, abiotic (geochemical), geomechanical and hydrodynamic processes. In the laboratory, MICP has been demonstrated to cement together heavily fractured shale and reduce the permeability of fractures in shale and sandstone cores up to five orders of magnitude under both ambient and subsurface relevant pressure conditions (Figure 1). Most recently, a MICP fracture treatment field study was performed at a well at the Southern Company Gorgas Steam Generation Plant (Alabama) (Figure 1). The Fayetteville Sandstone at approximately 1120' below ground surface was hydraulically fractured prior to MICP treatment. After 4 days of injection of 24 calcium pulses and 6 microbial inoculations, injectivity of brine into the formation was significantly reduced. The experiment also resulted in a reduction in pressure decay which is a measure of improved wellbore integrity. These promising results suggest the potential for MICP treatment to seal fractured pathways at the field scale to improve the long-term security of geologically-stored carbon dioxide or prevent leakage of shale gas or hydraulic fracturing fluids into functional overlying aquifers, reducing environmental impacts.

  1. Bioremediation of Cd by strain GZ-22 isolated from mine soil based on biosorption and microbially induced carbonate precipitation.

    PubMed

    Zhao, Yue; Yao, Jun; Yuan, Zhimin; Wang, Tianqi; Zhang, Yiyue; Wang, Fei

    2017-01-01

    Microbially induced carbonate precipitation (MICP) is an emerging and promising bioremediation technology to restore the environment polluted by heavy metals. Carbonate-biomineralization microbe can immobilize heavy metals from mobile species into stable crystals. In the present manuscript, laboratory batch studies were conducted to evaluate the Cd removal ability based on biosorption and MICP, using carbonate-biomineralization microbe GZ-22 isolated from a mine soil. This strain was identified as a Bacillus sp. according to 16S rDNA gene sequence analysis. Results of batch experiments revealed that MICP of the strain GZ-22 showed a greater potential to remove Cd than biomass biosorption under different impact factors such as pH, initial Cd concentration, and contact time. The optimum pH for MICP was 6 (50.34 %), while for biomass biosorption, it was 5 (38.81 %). When the initial concentration of Cd was 10 mg/L, removal efficiency induced by MICP was 53.06 % after 3 h, which was about 11 % greater than the removal efficiency induced by adsorption. The Cd removal efficiency increased as reaction time. The maximum removal efficiency based on MICP can reach 60.72 % at 10 mg/L for 48 h compared with 56.27 % by biosorption. X-ray diffractomer (XRD) revealed that Cd was transformed into CdCO3 by MICP of GZ-22. The present illustrated that the carbonate-biomineralization microbe GZ-22 can offer an effective and eco-friendly approach to immobilize soluble Cd and that MICP may play an important role in heavy metal bioremediation.

  2. The impact of polymeric excipients on the particle size of poorly soluble drugs after pH-induced precipitation.

    PubMed

    Punčochová, Kateřina; Prajzlerová, Marie; Beránek, Josef; Štěpánek, František

    2016-12-01

    Active pharmaceutical ingredients (APIs) with strongly pH-dependent aqueous solubility can face the problem of precipitating from solution when the pH changes from acidic in the stomach to neutral in the intestine. The present work investigates the effect of two polymeric excipients - polyvinylpyrrolidone (PVP) and Soluplus - on the ability to either prevent precipitation, or to control the size distribution of precipitated particles when precipitation cannot be prevented. Two different APIs were compared, Dabigatran etexilate mesylate and Rilpivirine hydrochloride. The effect of excipient concentration on the precipitation behaviour during pH titration was systematically investigated and qualitatively different trends were observed: in case of Soluplus, which forms a micellar solution when critical micelle concentration is exceeded, precipitation was inhibited in the case of Dabigatran etexilate, which partitioned into the micelles. On the other hand, Rilpivirine precipitated independently of Soluplus concentration. In the case of PVP, which does not form micelles, precipitation could not be avoided. Increased polymer concentration, however prevented the aggregation of precipitated particles into larger cluster. The observed effect of PVP was especially pronounced for Rilpivirine. The main conclusion of this study is that a suitably chosen polymeric excipient can either prevent precipitation altogether or reduce the size of the resulting particles. The mechanism of action, however, seems-specific to a given molecule. It was also shown that the polymer-stabilised particles have a potential to redissolve.

  3. Differential effects of gram-positive and gram-negative bacterial products on morphine induced inhibition of phagocytosis

    PubMed Central

    Jana, Ninkovic; Vidhu, Anand; Raini, Dutta; Zhang, Li; Saluja, Anuj; Meng, Jingjing; Lisa, Koodie; Santanu, Banerjee; Sabita, Roy

    2016-01-01

    Opioid drug abusers have a greater susceptibility to gram positive (Gram (+)) bacterial infections. However, the mechanism underlying opioid modulation of Gram (+) versus Gram (−) bacterial clearance has not been investigated. In this study, we show that opioid treatment resulted in reduced phagocytosis of Gram (+), when compared to Gram (−) bacteria. We further established that LPS priming of chronic morphine treated macrophages leads to potentiated phagocytosis and killing of both Gram (+) and Gram (−) bacteria in a P-38 MAP kinase dependent signaling pathway. In contrast, LTA priming lead to inhibition of both phagocytosis and bacterial killing. This study demonstrates for the first time the differential effects of TLR4 and TLR2 agonists on morphine induced inhibition of phagocytosis. Our results suggest that the incidence and severity of secondary infections with Gram (+) bacteria would be higher in opioid abusers. PMID:26891899

  4. Differential effects of gram-positive and gram-negative bacterial products on morphine induced inhibition of phagocytosis.

    PubMed

    Ninkovic, Jana; Jana, Ninkovic; Anand, Vidhu; Vidhu, Anand; Dutta, Raini; Raini, Dutta; Zhang, Li; Saluja, Anuj; Meng, Jingjing; Koodie, Lisa; Lisa, Koodie; Banerjee, Santanu; Santanu, Banerjee; Roy, Sabita; Sabita, Roy

    2016-02-19

    Opioid drug abusers have a greater susceptibility to gram positive (Gram (+)) bacterial infections. However, the mechanism underlying opioid modulation of Gram (+) versus Gram (-) bacterial clearance has not been investigated. In this study, we show that opioid treatment resulted in reduced phagocytosis of Gram (+), when compared to Gram (-) bacteria. We further established that LPS priming of chronic morphine treated macrophages leads to potentiated phagocytosis and killing of both Gram (+) and Gram (-) bacteria in a P-38 MAP kinase dependent signaling pathway. In contrast, LTA priming lead to inhibition of both phagocytosis and bacterial killing. This study demonstrates for the first time the differential effects of TLR4 and TLR2 agonists on morphine induced inhibition of phagocytosis. Our results suggest that the incidence and severity of secondary infections with Gram (+) bacteria would be higher in opioid abusers.

  5. Effect of the thermionic emission on the recombination and electron beam induced current contrast at the interface of a metallic precipitate embedded in a semiconductor matrix

    SciTech Connect

    Tarento, R.-J.; Debez, M.; Mekki, D. E.; Djemel, A.

    2013-12-15

    The barrier height and the recombination velocity at the interface between a metallic precipitate and a semiconductor matrix are investigated with a new self consistent procedure based both on the analysis of the recombination and emission balance rates for electrons and holes and on the determination of the size-dependent electronic structure of the embedded precipitate. In the present work, the precipitate is modeled within the spherical well potential framework. The main result is the dependence of the recombination features on the electronic structure of the metal precipitate unlike the models based only on the Shockley-Read-Hall theory. The behaviors of the surface charge density on the metallic precipitate and the barrier height versus the precipitate size are similar to our previous studies. Unlike previous works, the recombination velocity reaches a constant non-zero value for sizes smaller than a critical size which is dependent on the defect concentration at the interface. The new dependencies of the recombination parameters are illustrated by the calculation of the electron beam induced current (EBIC) contrast at the interface.

  6. Assessing the impact of polymers on the pH-induced precipitation behavior of poorly water soluble compounds using synchrotron wide angle X-ray scattering.

    PubMed

    Hsieh, Yi-Ling; Box, Karl; Taylor, Lynne S

    2014-09-01

    The aim of this study was to investigate the pH-induced precipitation behavior of four ionizable compounds (papaverine, dipyridamole, glyburide, and warfarin) in the absence and presence of polymers. Polymers selected included nonionic, anionic, and cationic polymers. Precipitates were analyzed immediately after formation using high-energy radiation wide-angle X-ray scattering analysis and polarized light microscopy. Papaverine immediately crystallized to the original solid-state form upon creation of a highly supersaturated solution and polymers were unable to prevent crystallization. Dipyridamole also crystallized rapidly, forming a metastable polymorph that was stabilized by several of the cellulosic polymers. For glyburide and warfarin, although the compounds readily crystallized in the absence of the polymers, several of the polymers were able to prevent crystallization for more than 6 h. In general, measurements of solution concentration immediately following precipitation corroborated the solid-state analysis results, with the solution phase for the noncrystalline precipitates having a concentration considerably higher than that of the equilibrium solubility value, whereas for the crystalline precipitates, values were closer to the equilibrium solubility. Thus, precipitation to a noncrystalline solid was found to be promoted by the presence of some polymers, resulting in the formation of a supersaturated solution.

  7. Discrimination of bacteria on food using laser-induced bacterial autofluorescence

    NASA Astrophysics Data System (ADS)

    Hilton, Peter J.; Plagmann, Manfred

    2000-12-01

    This paper updates progress on work1 in detecting bacterial auto-fluorescence against various food backgrounds using Laser-Induced Fluorescence (LIE). The fluorescence of bacteria and various meat products has been measured in order to find suitable excitation and detection wavelengths for discriminative imaging. The optical absorption of bacteria, meat and fish tissue was measured to provide a starting point for the fluorescence measurements. The bacteria measured was Escherichia Coli, and the food tissue products were, lamb, pork, chicken and fish. All absorption spectra have a peak around 400nm and most muscle tissue types have lower absorption around 325nm giving a good low contrast fluorescent background for the F. Coli. However, other tissue types such as fat, skin and bone skin have higher absorption levels and hence fluorescence. Three interference filters can be used to selectively sample the fluorescence spectra to generate a three point intensity ratio that can be used to discriminate between fluorescence of the various tissue types and E. Coli. The best fluorescence discrimination was achieved using the HeCd laser wavelength of 325nm. However in our current experimental setup there is not enough optical power at 325nm for direct laser imaging. We are currently working to increase UV laser excitation levels by using a dye laser to pump a frequency doubling crystal.

  8. Label-Free Bacterial Imaging with Deep-UV-Laser-Induced Native Fluorescence ▿ †

    PubMed Central

    Bhartia, Rohit; Salas, Everett C.; Hug, William F.; Reid, Ray D.; Lane, Arthur L.; Edwards, Katrina J.; Nealson, Kenneth H.

    2010-01-01

    We introduce a near-real-time optical imaging method that works via the detection of the intrinsic fluorescence of life forms upon excitation by deep-UV (DUV) illumination. A DUV (<250-nm) source enables the detection of microbes in their native state on natural materials, avoiding background autofluorescence and without the need for fluorescent dyes or tags. We demonstrate that DUV-laser-induced native fluorescence can detect bacteria on opaque surfaces at spatial scales ranging from tens of centimeters to micrometers and from communities to single cells. Given exposure times of 100 μs and low excitation intensities, this technique enables rapid imaging of bacterial communities and cells without irreversible sample alteration or destruction. We also demonstrate the first noninvasive detection of bacteria on in situ-incubated environmental experimental samples from the deep ocean (Lo'ihi Seamount), showing the use of DUV native fluorescence for in situ detection in the deep biosphere and other nutrient-limited environments. PMID:20817797

  9. Septic Shock Induced by Bacterial Prostatitis with Morganella morganii subsp. morganii in a Posttransplantation Patient

    PubMed Central

    Li, Xiaofan; Chen, Jianhui

    2015-01-01

    Bacterial infection is a common complication after Hematopoietic Stem Cell Transplantation (HSCT). Morganella morganii is ubiquitous Gram-negative facultative anaerobe, which may cause many kinds of opportunistic infection. Herein we report a case of a 55-year-old man who presented with frequent urination, urgency, and mild pain that comes and goes low in the abdomen and around the anus. The patient had a medical history of chronic prostatitis for 4 years. He received HLA-matched sibling allo-HSCT because of angioimmunoblastic T-cell lymphoma 29 months ago. The routine examination of prostatic fluid showed increased leukocytes and the culture of prostatic fluid showed Morganella morganii subsp. morganii. The patient developed chills and fever 18 hours after examination. Both urine culture and blood culture showed Morganella morganii subsp. morganii. The patient was successfully treated with antibiotic therapy and septic shock management. Taken together, Morganella morganii should be considered a possible pathogen when immunocompromised patients develop prostatitis. Also, prostatic massage could be a possible trigger of septic shock induced by Morganella morganii subsp. morganii in a posttransplantation patient. PMID:26798544

  10. Contribution of virus-induced lysis and protozoan grazing to benthic bacterial mortality estimated simultaneously in microcosms.

    PubMed

    Fischer, Ulrike R; Wieltschnig, Claudia; Kirschner, Alexander K T; Velimirov, Branko

    2006-08-01

    In contrast to the water column, the fate of bacterial production in freshwater sediments is still a matter of debate. Thus, the importance of virus-induced lysis and protozoan grazing of bacteria was investigated for the first time simultaneously in a silty sediment layer of a mesotrophic oxbow lake. Microcosms were installed in the laboratory in order to study the dynamics of these processes over 15 days. All microbial and physicochemical parameters showed acceptable resemblance to field data observed during a concomitant in situ study, and similar conclusions can be drawn with respect to the quantitative impact of viruses and protozoa on the bacterial compartment. Viral decay rates ranged from undetectable to 0.078 h(-1) (average, 0.033 h(-1)), and the control of bacterial production from below the detection limit to 36% (average, 12%). The contribution of virus-induced lysis of bacteria to the dissolved organic matter pool as well as to benthic bacterial nutrition was low. Ingestion rates of protozoan grazers ranged from undetectable to 24.7 bacteria per heterotrophic nanoflagellate (HNF) per hour (average, 4.8 bacteria HNF(-1) h(-1)) and from undetectable to 73.3 bacteria per ciliate per hour (average, 11.2 bacteria ciliate(-1) h(-1)). Heterotrophic nanoflagellate and ciliates together cropped up to 5% (average, 1%) of bacterial production. The viral impact on bacteria prevailed over protozoan grazing by a factor of 2.5-19.9 (average, 9.5). In sum, these factors together removed up to 36% (average, 12%) of bacterial production. The high number of correlations between viral and protozoan parameters is discussed in view of a possible relationship between virus removal and the presence of protozoan grazers.

  11. Energy Deposition and Escape Fluxes Induced by Energetic Solar Wind Ions and ENAs Precipitating into Mars Atmosphere: Accurate Consideration of Energy Transfer Collisions

    NASA Astrophysics Data System (ADS)

    Kharchenko, V. A.; Lewkow, N.; Gacesa, M.

    2014-12-01

    Formation and evolution of neutral fluxes of atoms and molecules escaping from the Mars atmosphere have been investigated for the sputtering and photo-chemical mechanisms. Energy and momentum transfer in collisions between the atmospheric gas and fast atoms and molecules have been considered using our recently obtained angular and energy dependent cross sections[1]. We have showed that accurate angular dependent collision cross sections are critical for the description of the energy relaxation of precipitating keV energetic ions/ENAs and for computations of altitude profiles of the fast atom and molecule production rates in recoil collisions. Upward and escape fluxes of the secondary energetic He and O atoms and H2, N2, CO and CO2 molecules, induced by precipitating ENAs, have been determined and their non-thermal energy distribution functions have been computed at different altitudes for different solar conditions. Precipitation and energy deposition of the energetic H2O molecules and products of their dissociations into the Mars atmosphere in the Comet C/2013 A1 (Siding Spring) - Mars interaction have been modeled using accurate cross sections. Reflection of precipitating ENAs by the Mars atmosphere has been analyzed in detail. [1] N. Lewkow and V. Kharchenko, "Precipitation of Energetic Neutral Atoms and Escape Fluxes induced from the Mars Atmosphere, ApJ, v.790, p.98 (2014).

  12. Bacterial modulins: a novel class of virulence factors which cause host tissue pathology by inducing cytokine synthesis.

    PubMed Central

    Henderson, B; Poole, S; Wilson, M

    1996-01-01

    Cytokines are a diverse group of proteins and glycoproteins which have potent and wide-ranging effects on eukaryotic cell function and are now recognized as important mediators of tissue pathology in infectious diseases. It is increasingly recognized that for many bacterial species, cytokine induction is a major virulence mechanism. Until recent years, the only bacterial component known to stimulate cytokine synthesis was lipopolysaccharide (LPS). It is only within the past decade that it has been clearly shown that many components associated with the bacterial cell wall, including proteins, glycoproteins, lipoproteins, carbohydrates, and lipids, have the capacity to stimulate mammalian cells to produce a diverse array of cytokines. It has been established that many of these cytokine-inducing molecules act by mechanisms distinct from that of LPS, and thus their activities are not due to LPS contamination. Bacteria produce a wide range of virulence factors which cause host tissue pathology, and these diverse factors have been grouped into four families: adhesins, aggressins, impedins, and invasins. We suggest that the array of bacterial cytokine-inducing molecules represents a new class of bacterial virulence factor, and, by analogy with the known virulence families, we suggest the term "modulin" to describe these molecules, because the action of cytokines is to modulate eukaryotic cell behavior. This review summarizes our current understanding of cytokine biology in relation to tissue homeostasis and disease and concisely reviews the current literature on the cytokine-inducing molecules produced by gram-negative and gram-positive bacteria, with an emphasis on the cellular mechanisms responsible for cytokine induction. We propose that modulins, by controlling the host immune and inflammatory responses, maintain the large commensal flora that all multicellular organisms support. PMID:8801436

  13. A small molecule deubiquitinase inhibitor increases localization of inducible nitric oxide synthase to the macrophage phagosome and enhances bacterial killing.

    PubMed

    Burkholder, Kristin M; Perry, Jeffrey W; Wobus, Christiane E; Donato, Nicholas J; Showalter, Hollis D; Kapuria, Vaibhav; O'Riordan, Mary X D

    2011-12-01

    Macrophages are key mediators of antimicrobial defense and innate immunity. Innate intracellular defense mechanisms can be rapidly regulated at the posttranslational level by the coordinated addition and removal of ubiquitin by ubiquitin ligases and deubiquitinases (DUBs). While ubiquitin ligases have been extensively studied, the contribution of DUBs to macrophage innate immune function is incompletely defined. We therefore employed a small molecule DUB inhibitor, WP1130, to probe the role of DUBs in the macrophage response to bacterial infection. Treatment of activated bone marrow-derived macrophages (BMM) with WP1130 significantly augmented killing of the intracellular bacterial pathogen Listeria monocytogenes. WP1130 also induced killing of phagosome-restricted bacteria, implicating a bactericidal mechanism associated with the phagosome, such as the inducible nitric oxide synthase (iNOS). WP1130 had a minimal antimicrobial effect in macrophages lacking iNOS, indicating that iNOS is an effector mechanism for WP1130-mediated bacterial killing. Although overall iNOS levels were not notably different, we found that WP1130 significantly increased colocalization of iNOS with the Listeria-containing phagosome during infection. Taken together, our data indicate that the deubiquitinase inhibitor WP1130 increases bacterial killing in macrophages by enhancing iNOS localization to the phagosome and suggest a potential role for ubiquitin regulation in iNOS trafficking.

  14. Atmospheric Rivers Induced Heavy Precipitation and Flooding in the Western U.S. Simulated by the WRF Regional Climate Model

    SciTech Connect

    Leung, Lai R.; Qian, Yun

    2009-02-12

    Twenty years of regional climate simulated by the Weather Research and Forecasting model for North America has been analyzed to study the influence of the atmospheric rivers and the role of the land surface on heavy precipitation and flooding in the western U.S. Compared to observations, the simulation realistically captured the 95th percentile extreme precipitation, mean precipitation intensity, as well as the mean precipitation and temperature anomalies of all the atmospheric river events between 1980-1999. Contrasting the 1986 President Day and 1997 New Year Day atmospheric river events, differences in atmospheric stability are found to have an influence on the spatial distribution of precipitation in the Coastal Range of northern California. Although both cases yield similar amounts of heavy precipitation, the 1997 case was found to produce more runoff compared to the 1986 case. Antecedent soil moisture, the ratio of snowfall to total precipitation (which depends on temperature), and existing snowpack all seem to play a role, leading to a higher runoff to precipitation ratio simulated for the 1997 case. This study underscores the importance of characterizing or simulating atmospheric rivers and the land surface conditions for predicting floods, and for assessing the potential impacts of climate change on heavy precipitation and flooding in the western U.S.

  15. Strontium Incorporation Into Calcite Generated by Bacterial Ureolysis

    NASA Astrophysics Data System (ADS)

    Fujita, Y.; Ingram, J. A.; Cortez, M. M.; Redden, G. D.; Smith, R. W.

    2002-12-01

    Strontium incorporation into calcite generated by bacterial ureolytic activity was investigated as part of a larger effort to evaluate the use of in situ urea hydrolysis for accelerating co-precipitation of trace metals and radionuclides in contaminated aquifers. 90Sr, a uranium fission product with a half-life of 29 years, is a significant subsurface contaminant at several Department of Energy facilities and could be immobilized using this remediation strategy. Experiments were conducted in a medium designed to simulate the groundwater of the Snake River Plain Aquifer in eastern Idaho, amended with strontium. Initially the solution was undersaturated with respect to calcite. As a model ureolytic organism, we used Bacillus pasteurii, a well-characterized bacterium known for high urease activity and previously shown to induce calcite precipitation in urea-amended medium. To gain information on the effect of the bacterial surfaces, we also looked at precipitation in the presence of a bacterial species that did not hydrolyze urea, as well as in the absence of bacteria. In the absence of bacterial ureolysis, carbonate precipitation was induced by addition of ammonium carbonate. All products were identified as calcite by X-ray diffraction. Strontium uptake was observed in all cases, but was greatest in the system including bacterial ureolysis. Sputter depth element profiling by time-of-flight secondary ion mass spectrometry (TOF-SIMS) confirmed this finding, showing highest Sr:Ca ratios in the bacterially generated calcite throughout the depth (~350 nm) investigated. Environmental Scanning Electron Microscopy (ESEM) of the solids revealed regular crystals containing the outlines of embedded or entombed bacterial cells, suggesting that calcite precipitated directly on the cell surfaces when present. Analysis by X-ray Absorption Near Edge Spectroscopy (XANES) indicated that in both the biotically and abiotically generated calcites the Sr was incorporated into the calcite

  16. Observation of a Saharan dust outbreaks in the frame of the Convective and Orographically-induced Precipitation Study

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Summa, Donato; Bhawar, Rohini; Di Iorio, Tatiana; Caccaini, Marco; Veselovskii, Igor; Kolgotin, Alexey

    2009-03-01

    The Raman lidar system BASIL was operational in Achern (Supersite R, Lat: 48.64° N, Long: 8.06° E, Elev.: 140 m) in the frame of the Convective and Orographically-induced Precipitation Study. BASIL operated continuously over a period of approx. 36 hours from 06:22 UTC on 1 August to 18:28 UTC on 2 August 2007, to cover IOPs 13 a-b. In this timeframe the signature of a severe Saharan dust outbreak episode was captured. An inversion algorithm was used to retrieve particle size distribution parameters, i.e., mean and effective radius, number, surface area, and volume concentration, and complex refractive index, as well as the parameters of a bimodal particle size distribution, from the multi-wavelength lidar data of particle backscattering and extinction. The inversion method employs Tikhonov's inversion with regularization. Size distribution parameters are estimated as a function of altitude at different times during the dust outbreak event. Retrieval results reveal the dominance in the upper dust layer of a coarse mode with radii 3-4 μm. Number density and volume concentration are in the range 100-800 cm-3 and 5-40 μm3/cm3, respectively, while real and imaginary part of the complex refractive index are in the range 1.41-1.53 and 0.003-0.014, respectively.

  17. Characterization of particle hygroscopicity by Raman lidar: Selected case studies from the convective and orographically-induced precipitation study

    NASA Astrophysics Data System (ADS)

    Stelitano, Dario; Di Girolamo, Paolo; Summa, Donato

    2013-05-01

    The characterization of particle hygroscopicity has primary importance for climate monitoring and prediction. Model studies have demonstrated that relative humidity (RH) has a critical influence on aerosol climate forcing. Hygroscopic properties of aerosols influence particle size distribution and refractive index and hence their radiative effects. Aerosol particles tend to grow at large relative humidity values as a result of their hygroscopicity. Raman lidars with aerosol, water vapor and temperature measurement capability are potentially attractive tools for studying aerosol hygroscopicity as in fact they can provide continuous altitude-resolved measurements of particle optical, size and microphysical properties, as well as relative humidity, without perturbing the aerosols or their environment. Specifically, the University of Basilicata Raman lidar system (BASIL) considered for the present study, has the capability to perform all-lidar measurements of relative humidity based on the application of both the rotational and the vibrational Raman lidar techniques in the UV. BASIL was operational in Achern (Black Forest, Lat: 48.64° N, Long: 8.06° E, Elev.: 140 m) between 25 May and 30 August 2007 in the framework of the Convective and Orographically-induced Precipitation Study (COPS). The present analysis is focused on selected case studies characterized by the presence of different aerosol types with different hygroscopic behavior. The observed behavior, dependent upon aerosol composition, may range from hygrophobic to strongly hygroscopic.

  18. Comparative proteomic analysis of casein and whey as prepared by chymosin-induced separation, isoelectric precipitation or ultracentrifugation.

    PubMed

    Jensen, Hanne B; Poulsen, Nina A; Møller, Hanne S; Stensballe, Allan; Larsen, Lotte B

    2012-11-01

    Fractionation of bovine milk was performed using chymosin-induced separation, isoelectric precipitation or ultracentrifugation as separation techniques prior to gel-based proteomic analysis. This approach allowed for comparative display and identification of proteins partitioned into casein and whey, respectively. Initially, three different staining methods (silver staining, colloidal Coomassie Blue G-250 or fluorescent Flamingo Pink staining) for two-dimensional gel electrophoresis (2-DGE) analysis were compared for their suitability as staining agent, especially in relation to their suitability to reveal differences in the casein fractions. Fluorescent staining proved to be the most appropriate for this purpose, giving a high sensitivity, and using this staining method, characteristic 2-DGE fingerprints were obtained for each casein and whey fraction from each separation method. A number of protein spots in both casein and whey fractions varied with separation method and these spots were subsequently identified using tandem mass spectrometry (MS). In rennet casein, proteolytic fragmentation of caseins (α(s1)-, α(s2),-, β- and κ-) was identified as a result of chymosin hydrolysis, whereas the 2-DGE profile of acid and ultracentrifuged casein was dominated by the presence of multiple isoforms of κ-caseins. Furthermore, casein remnants were identified in milk serum after ultracentrifugation. This study shows that gel-based proteomic analysis is suitable for characterisation of subtle variations in protein composition of milk fractions that occur as a consequence of different milk fractionation strategies.

  19. Cheese 'refinement' with whey B-vitamin removal during precipitation potentially induces temporal 'functional' dietary shortage: homocysteine as a biomarker.

    PubMed

    Shapira, N

    2014-07-25

    Cottage cheese 'refinement' with massive B-vitamin losses (≈70-84%) through whey removal during precipitation may potentially induce an acute imbalance between protein/methionine load and temporal inadequacy/shortage of nutrients critical for their metabolism, i.e. B6 and B12. The temporal effect of cottage cheese consumption was evaluated using increased plasma homocysteine as a B-vitamin shortage marker. In a double-blind study, healthy, normal-weight (BMI = 22-27), premenopausal women aged 25-45 years were first given a methionine load (100 mg kg(-1), n = 15), then cottage cheese alone (500 g, ≈50 g protein, ≈1200 mg methionine, n = 49) at breakfast, and then with added B6 (2 mg, n = 8) and/or B6 + folate (1 mg + 200 mcg, n = 7). Plasma homocysteine was measured preprandially (t0) and then postprandially 5 h (t5) and ≥6-24 h. Cheese-induced homocysteine increased 28.7% (p ≤ 0.001), ≈60% of the free methionine response, remaining higher through ≥6-8 h. Co-supplementation with B6 reduced the Hcy increase by 45.0% (to 14.9%, p = 0.025), and that with B6 + folate reduced the Hcy increase by 72.3% (to 7.5%, p = 0.556, NS). Homocysteine increased more in participants with lower baselines (<5 μM vs. ≥5 μM, p ≤ 0.001) following cheese, ≈3-fold (54.8% vs. 18.5%) or methionine, 47.3% (266.7% vs. 181.1%). Cheese B-vitamin depletion - i.e. to B6 ≈ 2.0-4.0 μg g(-1) protein, far below women's metabolic requirement (15-20 μg g(-1)) - appeared to induce acute relative shortage compared to methionine/protein loads, exemplified by greater homocysteine increases than with other animal proteins (previous data), more so with lower baseline homocysteine. Smaller increases following re-supplementation demonstrated potential for 'functional fortification'/co-supplementation. Unnoted cheese 'refinement', like white bread, potentially induces episodic vitamin shortage effects, warranting consideration for acute/cumulative implications, alternative processing

  20. Multi-satellite sensor study on precipitation-induced emission pulses of NOx from soils in semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    Zörner, Jan; Penning de Vries, Marloes; Beirle, Steffen; Sihler, Holger; Veres, Patrick R.; Williams, Jonathan; Wagner, Thomas

    2016-07-01

    We present a top-down approach to infer and quantify rain-induced emission pulses of NOx ( ≡ NO + NO2), stemming from biotic emissions of NO from soils, from satellite-borne measurements of NO2. This is achieved by synchronizing time series at single grid pixels according to the first day of rain after a dry spell of prescribed duration. The full track of the temporal evolution several weeks before and after a rain pulse is retained with daily resolution. These are needed for a sophisticated background correction, which accounts for seasonal variations in the time series and allows for improved quantification of rain-induced soil emissions. The method is applied globally and provides constraints on pulsed soil emissions of NOx in regions where the NOx budget is seasonally dominated by soil emissions. We find strong peaks of enhanced NO2 vertical column densities (VCDs) induced by the first intense precipitation after prolonged droughts in many semi-arid regions of the world, in particular in the Sahel. Detailed investigations show that the rain-induced NO2 pulse detected by the OMI (Ozone Monitoring Instrument), GOME-2 and SCIAMACHY satellite instruments could not be explained by other sources, such as biomass burning or lightning, or by retrieval artefacts (e.g. due to clouds). For the Sahel region, absolute enhancements of the NO2 VCDs on the first day of rain based on OMI measurements 2007-2010 are on average 4 × 1014  molec cm-2 and exceed 1 × 1015  molec cm-2 for individual grid cells. Assuming a NOx lifetime of 4 h, this corresponds to soil NOx emissions in the range of 6 up to 65 ng N m-2 s-1, which is in good agreement with literature values. Apart from the clear first-day peak, NO2 VCDs are moderately enhanced (2 × 1014  molec cm-2) compared to the background over the following 2 weeks, suggesting potential further emissions during that period of about 3.3 ng N m-2 s-1

  1. A membrane basis for bacterial identification and discrimination using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Rehse, Steven J.; Jeyasingham, Narmatha; Diedrich, Jonathan; Palchaudhuri, Sunil

    2009-05-01

    Nanosecond single-pulse laser-induced breakdown spectroscopy (LIBS) has been used to discriminate between two different genera of Gram-negative bacteria and between several strains of the Escherichia coli bacterium based on the relative concentration of trace inorganic elements in the bacteria. Of particular importance in all such studies to date has been the role of divalent cations, specifically Ca2+ and Mg2+, which are present in the membranes of Gram-negative bacteria and act to aggregate the highly polar lipopolysaccharide molecules. We have demonstrated that the source of emission from Ca and Mg atoms observed in LIBS plasmas from bacteria is at least partially located at the outer membrane by intentionally altering membrane biochemistry and correlating these changes with the observed changes in the LIBS spectra. The definitive assignment of some fraction of the LIBS emission to the outer membrane composition establishes a potential serological, or surface-antigen, basis for the laser-based identification. E. coli and Pseudomonas aeruginosa were cultured in three nutrient media: trypticase soy agar as a control, a MacConkey agar with a 0.01% concentration of bile salts including sodium deoxycholate, and a trypticase soy agar with a 0.4% deoxycholate concentration. The higher concentration of deoxycholate is known to disrupt bacterial outer membrane integrity and was expected to induce changes in the observed LIBS spectra. Altered LIBS emission was observed for bacteria cultured in this 0.4% medium and laser ablated in an all-argon environment. These spectra evidenced a reduced calcium emission and in the case of one species, a reduced magnesium emission. Culturing on the lower (0.01%) concentration of bile salts altered the LIBS spectra for both the P. aeruginosa and two strains of E. coli in a highly reproducible way, although not nearly as significantly as culturing in the higher concentration of deoxycholate did. This was possibly due to the accumulation

  2. Host-induced bacterial cell wall decomposition mediates pattern-triggered immunity in Arabidopsis

    PubMed Central

    Liu, Xiaokun; Grabherr, Heini M; Willmann, Roland; Kolb, Dagmar; Brunner, Frédéric; Bertsche, Ute; Kühner, Daniel; Franz-Wachtel, Mirita; Amin, Bushra; Felix, Georg; Ongena, Marc; Nürnberger, Thorsten; Gust, Andrea A

    2014-01-01

    Peptidoglycans (PGNs) are immunogenic bacterial surface patterns that trigger immune activation in metazoans and plants. It is generally unknown how complex bacterial structures such as PGNs are perceived by plant pattern recognition receptors (PRRs) and whether host hydrolytic activities facilitate decomposition of bacterial matrices and generation of soluble PRR ligands. Here we show that Arabidopsis thaliana, upon bacterial infection or exposure to microbial patterns, produces a metazoan lysozyme-like hydrolase (lysozyme 1, LYS1). LYS1 activity releases soluble PGN fragments from insoluble bacterial cell walls and cleavage products are able to trigger responses typically associated with plant immunity. Importantly, LYS1 mutant genotypes exhibit super-susceptibility to bacterial infections similar to that observed on PGN receptor mutants. We propose that plants employ hydrolytic activities for the decomposition of complex bacterial structures, and that soluble pattern generation might aid PRR-mediated immune activation in cell layers adjacent to infection sites. DOI: http://dx.doi.org/10.7554/eLife.01990.001 PMID:24957336

  3. Ruthenium red-induced bundling of bacterial cell division protein, FtsZ.

    PubMed

    Santra, Manas Kumar; Beuria, Tushar K; Banerjee, Abhijit; Panda, Dulal

    2004-06-18

    The assembly of FtsZ plays a major role in bacterial cell division, and it is thought that the assembly dynamics of FtsZ is a finely regulated process. Here, we show that ruthenium red is able to modulate FtsZ assembly in vitro. In contrast to the inhibitory effects of ruthenium red on microtubule polymerization, we found that a substoichiometric concentration of ruthenium red strongly increased the light-scattering signal of FtsZ assembly. Further, sedimentable polymer mass was increased by 1.5- and 2-fold in the presence of 2 and 10 microm ruthenium red, respectively. In addition, ruthenium red strongly reduced the GTPase activity and prevented dilution-induced disassembly of FtsZ polymers. Electron microscopic analysis showed that 4-10 microm of ruthenium red produced thick bundles of FtsZ polymers. The significant increase in the light-scattering signal and pelletable polymer mass in the presence of ruthenium red seemed to be due to the bundling of FtsZ protofilaments into larger polymers rather than the actual increase in the level of polymeric FtsZ. Furthermore, ruthenium red was found to copolymerize with FtsZ, and the copolymerization of substoichiometric amounts of ruthenium red with FtsZ polymers promoted cooperative assembly of FtsZ that produced large bundles. Calcium inhibited the binding of ruthenium red to FtsZ. However, a concentration of calcium 1000-fold higher than that of ruthenium red was required to produce similar effects on FtsZ assembly. Ruthenium red strongly modulated FtsZ polymerization, suggesting the presence of an important regulatory site on FtsZ and suggesting that a natural ligand, which mimics the action of ruthenium red, may regulate the assembly of FtsZ in bacteria.

  4. Giardia duodenalis induces paracellular bacterial translocation and causes postinfectious visceral hypersensitivity.

    PubMed

    Halliez, Marie C M; Motta, Jean-Paul; Feener, Troy D; Guérin, Gaetan; LeGoff, Laetitia; François, Arnaud; Colasse, Elodie; Favennec, Loic; Gargala, Gilles; Lapointe, Tamia K; Altier, Christophe; Buret, André G

    2016-04-15

    Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal disorder. It is characterized by abdominal hypersensitivity, leading to discomfort and pain, as well as altered bowel habits. While it is common for IBS to develop following the resolution of infectious gastroenteritis [then termed postinfectious IBS (PI-IBS)], the mechanisms remain incompletely understood. Giardia duodenalis is a cosmopolitan water-borne enteropathogen that causes intestinal malabsorption, diarrhea, and postinfectious complications. Cause-and-effect studies using a human enteropathogen to help investigate the mechanisms of PI-IBS are sorely lacking. In an attempt to establish causality between giardiasis and postinfectious visceral hypersensitivity, this study describes a new model of PI-IBS in neonatal rats infected with G. duodenalis At 50 days postinfection with G. duodenalis (assemblage A or B), long after the parasite was cleared, rats developed visceral hypersensitivity to luminal balloon distension in the jejunum and rectum, activation of the nociceptive signaling pathway (increased c-fos expression), histological modifications (villus atrophy and crypt hyperplasia), and proliferation of mucosal intraepithelial lymphocytes and mast cells in the jejunum, but not in the rectum. G. duodenalis infection also disrupted the intestinal barrier, in vivo and in vitro, which in turn promoted the translocation of commensal bacteria. Giardia-induced bacterial paracellular translocation in vitro correlated with degradation of the tight junction proteins occludin and claudin-4. The extensive observations associated with gut hypersensitivity described here demonstrate that, indeed, in this new model of postgiardiasis IBS, alterations to the gut mucosa and c-fos are consistent with those associated with PI-IBS and, hence, offer avenues for new mechanistic research in the field.

  5. Evaporation-induced stimulation of bacterial osmoregulation for electrical assessment of cell viability

    PubMed Central

    Ebrahimi, Aida; Alam, Muhammad Ashraful

    2016-01-01

    Bacteria cells use osmoregulatory proteins as emergency valves to respond to changes in the osmotic pressure of their external environment. The existence of these emergency valves has been known since the 1960s, but they have never been used as the basis of a viability assay to tell dead bacteria cells apart from live ones. In this paper, we show that osmoregulation provides a much faster, label-free assessment of cell viability compared with traditional approaches that rely on cell multiplication (growth) to reach a detectable threshold. The cells are confined in an evaporating droplet that serves as a dynamic microenvironment. Evaporation-induced increase in ionic concentration is reflected in a proportional increase of the droplet’s osmotic pressure, which in turn, stimulates the osmoregulatory response from the cells. By monitoring the time-varying electrical conductance of evaporating droplets, bacterial cells are identified within a few minutes compared with several hours in growth-based methods. To show the versatility of the proposed method, we show detection of WT and genetically modified nonhalotolerant cells (Salmonella typhimurium) and dead vs. live differentiation of nonhalotolerant (such as Escherichia coli DH5α) and halotolerant cells (such as Staphylococcus epidermidis). Unlike the growth-based techniques, the assay time of the proposed method is independent of cell concentration or the bacteria type. The proposed label-free approach paves the road toward realization of a new class of real time, array-formatted electrical sensors compatible with droplet microfluidics for laboratory on a chip applications. PMID:27303045

  6. Atmospheric pressure resistive barrier air plasma jet induced bacterial inactivation in aqueous environment

    NASA Astrophysics Data System (ADS)

    Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier

    2013-03-01

    An atmospheric pressure resistive barrier air plasma jet is designed to inactivate bacteria in aqueous media in direct and indirect exposure modes of treatment. The resistive barrier plasma jet is designed to operate at both dc and standard 50-60 Hz low frequency ac power input and the ambient air at 50% humidity level was used as the operating gas. The voltage-current characteristics of the plasma jet were analyzed and the operating frequency of the discharge was measured to be 20 kHz and the plasma power was measured to be 26 W. The plasma jet rotational temperatures (Trot) are obtained from the optical emission spectra, from the N2C-B(2+) transitions by matching the experimental spectrum results with the Spectra Air (SPECAIR) simulation spectra. The reactive oxygen and nitrogen species were measured using optical emission spectroscopy and gas analyzers, for direct and indirect treatment modes. The nitric oxides (NO) were observed to be the predominant long lived reactive nitrogen species produced by the plasma. Three different bacteria including Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Neisseria meningitidis (Gram-negative) were suspended in an aqueous media and treated by the resistive barrier air plasma jet in direct and indirect exposure modes. The results show that a near complete bacterial inactivation was achieved within 120 s for both direct and indirect plasma treatment of S. aureus and E. coli bacteria. Conversely, a partial inactivation of N. meningitidis was observed by 120 s direct plasma exposure and insignificant inactivation was observed for the indirect plasma exposure treatment. Plasma induced shifts in N. meningitidis gene expression was analyzed using pilC gene expression as a representative gene and the results showed a reduction in the expression of the pilC gene compared to untreated samples suggesting that the observed protection against NO may be regulated by other genes.

  7. Photodynamic therapy can induce non-specific protective immunity against a bacterial infection

    NASA Astrophysics Data System (ADS)

    Tanaka, Masamitsu; Mroz, Pawel; Dai, Tianhong; Kinoshita, Manabu; Morimoto, Yuji; Hamblin, Michael R.

    2012-03-01

    Photodynamic therapy (PDT) for cancer is known to induce an immune response against the tumor, in addition to its well-known direct cell-killing and vascular destructive effects. PDT is becoming increasingly used as a therapy for localized infections. However there has not to date been a convincing report of an immune response being generated against a microbial pathogen after PDT in an animal model. We have studied PDT as a therapy for bacterial arthritis caused by Staphylococcus aureus infection in the mouse knee. We had previously found that PDT of an infection caused by injection of MRSA (5X107 CFU) into the mouse knee followed 3 days later by 1 μg of Photofrin and 635- nm diode laser illumination with a range of fluences within 5 minutes, gave a biphasic dose response. The greatest reduction of MRSA CFU was seen with a fluence of 20 J/cm2, whereas lower antibacterial efficacy was observed with fluences that were either lower or higher. We then tested the hypothesis that the host immune response mediated by neutrophils was responsible for most of the beneficial antibacterial effect. We used bioluminescence imaging of luciferase expressing bacteria to follow the progress of the infection in real time. We found similar results using intra-articular methylene blue and red light, and more importantly, that carrying out PDT of the noninfected joint and subsequently injecting bacteria after PDT led to a significant protection from infection. Taken together with substantial data from studies using blocking antibodies we believe that the pre-conditioning PDT regimen recruits and stimulates neutrophils into the infected joint which can then destroy bacteria that are subsequently injected and prevent infection.

  8. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    PubMed Central

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  9. Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis.

    PubMed

    Svahn, Sara L; Ulleryd, Marcus A; Grahnemo, Louise; Ståhlman, Marcus; Borén, Jan; Nilsson, Staffan; Jansson, John-Olov; Johansson, Maria E

    2016-04-01

    Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics,S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival.

  10. Delayed development induced by toxicity to the host can be inherited by a bacterial-dependent, transgenerational effect

    PubMed Central

    Fridmann-Sirkis, Yael; Stern, Shay; Elgart, Michael; Galili, Matana; Zeisel, Amit; Shental, Noam; Soen, Yoav

    2014-01-01

    Commensal gut bacteria in many species including flies are integral part of their host, and are known to influence its development and homeostasis within generation. Here we report an unexpected impact of host–microbe interactions, which mediates multi-generational, non-Mendelian inheritance of a stress-induced phenotype. We have previously shown that exposure of fly larvae to G418 antibiotic induces transgenerationally heritable phenotypes, including a delay in larval development, gene induction in the gut and morphological changes. We now show that G418 selectively depletes commensal Acetobacter species and that this depletion explains the heritable delay, but not the inheritance of the other phenotypes. Notably, the inheritance of the delay was mediated by a surprising trans-generational effect. Specifically, bacterial removal from F1 embryos did not induce significant delay in F1 larvae, but nonetheless led to a considerable delay in F2. This effect maintains a delay induced by bacterial-independent G418 toxicity to the host. In line with these findings, reintroduction of isolated Acetobacter species prevented the inheritance of the delay. We further show that this prevention is partly mediated by vitamin B2 (Riboflavin) produced by these bacteria; exogenous Riboflavin led to partial prevention and inhibition of Riboflavin synthesis compromised the ability of the bacteria to prevent the inheritance. These results identify host–microbe interactions as a hitherto unrecognized factor capable of mediating non-Mendelian inheritance of a stress-induced phenotype. PMID:24611070

  11. Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis

    PubMed Central

    Ulleryd, Marcus A.; Grahnemo, Louise; Ståhlman, Marcus; Borén, Jan; Nilsson, Staffan; Jansson, John-Olov

    2016-01-01

    Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics, S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus. Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival. PMID:26857576

  12. Bacterial Infection of Fly Ovaries Reduces Egg Production and Induces Local Hemocyte Activation

    PubMed Central

    Brandt, Stephanie M.; Schneider, David S.

    2009-01-01

    Summary Morbidity, the state of being diseased, is an important aspect of pathogenesis that has gone relatively unstudied in fruit flies. Our interest is in characterizing how bacterial pathogenesis affects various physiologies of the fly. We chose to examine the fly ovary because we found bacterial infection had a striking effect on fly reproduction. We observed decreased egg laying after bacterial infection that correlated with increased bacterial virulence. We also found that bacteria colonized the ovary in a previously undescribed manner; bacteria were found in the posterior of the ovary, adjacent to the lateral oviduct. This local infection in the ovary resulted in melanization and activation of the cellular immune response at the site of infection. PMID:17400292

  13. Changes in soil bacterial community triggered by drought-induced gap succession preceded changes in soil C stocks and quality.

    PubMed

    Yuste, Jorge Curiel; Barba, Josep; Fernandez-Gonzalez, Antonio José; Fernandez-Lopez, Manuel; Mattana, Stefania; Martinez-Vilalta, Jordi; Nolis, Pau; Lloret, Francisco

    2012-12-01

    The aim of this study was to understand how drought-induced tree mortality and subsequent secondary succession would affect soil bacterial taxonomic composition as well as soil organic matter (SOM) quantity and quality in a mixed Mediterranean forest where the Scots pine (Pinus sylvestris) population, affected by climatic drought-induced die-off, is being replaced by Holm-oaks (HO; Quercus ilex). We apply a high throughput DNA pyrosequencing technique and (13)C solid-state Nuclear Magnetic Resonance (CP-MAS (13)C NMR) to soils within areas of influence (defined as an surface with 2-m radius around the trunk) of different trees: healthy and affected (defoliated) pines, pines that died a decade ago and healthy HOs. Soil respiration was also measured in the same spots during a spring campaign using a static close-chamber method (soda lime). A decade after death, and before aerial colonization by the more competitive HOs have even taken place, we could not find changes in soil C pools (quantity and/or quality) associated with tree mortality and secondary succession. Unlike C pools, bacterial diversity and community structure were strongly determined by tree mortality. Convergence between the most abundant taxa of soil bacterial communities under dead pines and colonizer trees (HOs) further suggests that physical gap colonization was occurring below-ground before above-ground colonization was taken place. Significantly higher soil respiration rates under dead trees, together with higher bacterial diversity and anomalously high representation of bacteria commonly associated with copiotrophic environments (r-strategic bacteria) further gives indications of how drought-induced tree mortality and secondary succession were influencing the structure of microbial communities and the metabolic activity of soils.

  14. Changes in soil bacterial community triggered by drought-induced gap succession preceded changes in soil C stocks and quality

    PubMed Central

    Yuste, Jorge Curiel; Barba, Josep; Fernandez-Gonzalez, Antonio José; Fernandez-Lopez, Manuel; Mattana, Stefania; Martinez-Vilalta, Jordi; Nolis, Pau; Lloret, Francisco

    2012-01-01

    The aim of this study was to understand how drought-induced tree mortality and subsequent secondary succession would affect soil bacterial taxonomic composition as well as soil organic matter (SOM) quantity and quality in a mixed Mediterranean forest where the Scots pine (Pinus sylvestris) population, affected by climatic drought-induced die-off, is being replaced by Holm-oaks (HO; Quercus ilex). We apply a high throughput DNA pyrosequencing technique and 13C solid-state Nuclear Magnetic Resonance (CP-MAS 13C NMR) to soils within areas of influence (defined as an surface with 2-m radius around the trunk) of different trees: healthy and affected (defoliated) pines, pines that died a decade ago and healthy HOs. Soil respiration was also measured in the same spots during a spring campaign using a static close-chamber method (soda lime). A decade after death, and before aerial colonization by the more competitive HOs have even taken place, we could not find changes in soil C pools (quantity and/or quality) associated with tree mortality and secondary succession. Unlike C pools, bacterial diversity and community structure were strongly determined by tree mortality. Convergence between the most abundant taxa of soil bacterial communities under dead pines and colonizer trees (HOs) further suggests that physical gap colonization was occurring below-ground before above-ground colonization was taken place. Significantly higher soil respiration rates under dead trees, together with higher bacterial diversity and anomalously high representation of bacteria commonly associated with copiotrophic environments (r-strategic bacteria) further gives indications of how drought-induced tree mortality and secondary succession were influencing the structure of microbial communities and the metabolic activity of soils. PMID:23301169

  15. Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth.

    PubMed

    Breton, Jonathan; Tennoune, Naouel; Lucas, Nicolas; Francois, Marie; Legrand, Romain; Jacquemot, Justine; Goichon, Alexis; Guérin, Charlène; Peltier, Johann; Pestel-Caron, Martine; Chan, Philippe; Vaudry, David; do Rego, Jean-Claude; Liénard, Fabienne; Pénicaud, Luc; Fioramonti, Xavier; Ebenezer, Ivor S; Hökfelt, Tomas; Déchelotte, Pierre; Fetissov, Sergueï O

    2016-02-09

    The composition of gut microbiota has been associated with host metabolic phenotypes, but it is not known if gut bacteria may influence host appetite. Here we show that regular nutrient provision stabilizes exponential growth of E. coli, with the stationary phase occurring 20 min after nutrient supply accompanied by bacterial proteome changes, suggesting involvement of bacterial proteins in host satiety. Indeed, intestinal infusions of E. coli stationary phase proteins increased plasma PYY and their intraperitoneal injections suppressed acutely food intake and activated c-Fos in hypothalamic POMC neurons, while their repeated administrations reduced meal size. ClpB, a bacterial protein mimetic of α-MSH, was upregulated in the E. coli stationary phase, was detected in plasma proportional to ClpB DNA in feces, and stimulated firing rate of hypothalamic POMC neurons. Thus, these data show that bacterial proteins produced after nutrient-induced E. coli growth may signal meal termination. Furthermore, continuous exposure to E. coli proteins may influence long-term meal pattern.

  16. EXAFS study on solute precipitation in FeCu alloy induced by energetic electron bombardments and thermal aging

    NASA Astrophysics Data System (ADS)

    Fujimura, Y.; Yoshizaki, H.; Nakagawa, Shou; Okamoto, Y.; Ishikawa, N.; Saitoh, Y.; Hori, F.; Iwase, A.

    2015-07-01

    The extended X-ray absorption fine structure (EXAFS) measurement is a useful tool for the observation of local atomic arrangements around selected atoms. We performed EXAFS measurements for the electron-irradiated and the thermally-aged Fe-0.6 wt.% Cu alloy and compared the experimental result with that of the simulation by the FEFF simulation code in order to investigate the local atomic structure around Cu atoms. Cu precipitates which were produced by the thermal aging at 773 K transformed from the bcc structure to the fcc structure as the precipitates grow large enough. However, for electron-irradiated specimens, although the hardness greatly increased, the transformation of Cu precipitates from the bcc to the fcc structure was not clearly confirmed. This result indicates that small sized Cu precipitates which had the bcc structure were produced by the electron irradiation and they could hardly coarsen during the irradiation.

  17. Summer precipitation anomalies in Asia and North America induced by Eurasian non-monsoon land heating versus ENSO.

    PubMed

    Zhao, Ping; Wang, Bin; Liu, Jiping; Zhou, Xiuji; Chen, Junming; Nan, Sulan; Liu, Ge; Xiao, Dong

    2016-02-26

    When floods ravage Asian monsoon regions in summer, megadroughts often attack extratropical North America, which feature an intercontinental contrasting precipitation anomaly between Asia and North America. However, the characteristics of the contrasting Asian-North American (CANA) precipitation anomalies and associated mechanisms have not been investigated specifically. In this article, we firmly establish this summer CANA pattern, providing evidence for a significant effect of the land surface thermal forcing over Eurasian non-monsoon regions on the CANA precipitation anomalies by observations and numerical experiments. We show that the origin of the CANA precipitation anomalies and associated anomalous anticyclones over the subtropical North Pacific and Atlantic has a deeper root in Eurasian non-monsoon land surface heating than in North American land surface heating. The ocean forcing from the ENSO is secondary and tends to be confined in the tropics. Our results have strong implications to interpretation of the feedback of global warming on hydrological cycle over Asia and North America. Under the projected global warming due to the anthropogenic forcing, the prominent surface warming over Eurasian non-monsoon regions is a robust feature which, through the mechanism discussed here, would favor a precipitation increase over Asian monsoon regions and a precipitation decrease over extratropical North America.

  18. Summer precipitation anomalies in Asia and North America induced by Eurasian non-monsoon land heating versus ENSO

    PubMed Central

    Zhao, Ping; Wang, Bin; Liu, Jiping; Zhou, Xiuji; Chen, Junming; Nan, Sulan; Liu, Ge; Xiao, Dong

    2016-01-01

    When floods ravage Asian monsoon regions in summer, megadroughts often attack extratropical North America, which feature an intercontinental contrasting precipitation anomaly between Asia and North America. However, the characteristics of the contrasting Asian-North American (CANA) precipitation anomalies and associated mechanisms have not been investigated specifically. In this article, we firmly establish this summer CANA pattern, providing evidence for a significant effect of the land surface thermal forcing over Eurasian non-monsoon regions on the CANA precipitation anomalies by observations and numerical experiments. We show that the origin of the CANA precipitation anomalies and associated anomalous anticyclones over the subtropical North Pacific and Atlantic has a deeper root in Eurasian non-monsoon land surface heating than in North American land surface heating. The ocean forcing from the ENSO is secondary and tends to be confined in the tropics. Our results have strong implications to interpretation of the feedback of global warming on hydrological cycle over Asia and North America. Under the projected global warming due to the anthropogenic forcing, the prominent surface warming over Eurasian non-monsoon regions is a robust feature which, through the mechanism discussed here, would favor a precipitation increase over Asian monsoon regions and a precipitation decrease over extratropical North America. PMID:26916258

  19. Suppression effects of dental glass-ceramics with polarization-induced highly dense surface charges against bacterial adhesion.

    PubMed

    Nozaki, Kosuke; Koizumi, Hiroki; Horiuchi, Naohiro; Nakamura, Miho; Okura, Toshinori; Yamashita, Kimihiro; Nagai, Akiko

    2015-01-01

    This study investigated the surface characteristics and antibacterial ability capacity of surface-improved dental glass-ceramics by an electrical polarization process. Commercially available dental glass-ceramic materials were electrically polarized to induce surface charges in a direct current field by heating. The surface morphology, chemical composition, crystal structure, and surface free energy (SFE) were evaluated using scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and water droplet methods, respectively. The antibacterial capacity was assessed by a bacterial adhesion test using Streptococcus mutans. Although the surface morphology, chemical composition, and crystal structure were not affected by electrical polarization, the polar component and total SFE were enhanced. After 24 h incubation at 37ºC, bacterial adhesion to the polarized samples was inhibited. The electrical polarization method may confer antibacterial properties on prosthetic devices, such as porcelain fused to metal crowns or all ceramic restorations, without any additional bactericidal agents.

  20. Caprylic acid-induced impurity precipitation from protein A capture column elution pool to enable a two-chromatography-step process for monoclonal antibody purification.

    PubMed

    Zheng, Ji; Wang, Lu; Twarowska, Barbara; Laino, Sarah; Sparks, Colleen; Smith, Timothy; Russell, Reb; Wang, Michelle

    2015-01-01

    This article presents the use of caprylic acid (CA) to precipitate impurities from the protein A capture column elution pool for the purification of monoclonal antibodies (mAbs) with the objective of developing a two chromatography step antibody purification process. A CA-induced impurity precipitation in the protein A column elution pool was evaluated as an alternative method to polishing chromatography techniques for use in the purification of mAbs. Parameters including pH, CA concentrations, mixing time, mAb concentrations, buffer systems, and incubation temperatures were evaluated on their impacts on the impurity removal, high-molecular weight (HMW) formation and precipitation step yield. Both pH and CA concentration, but not mAb concentrations and buffer systems, are key parameters that can affect host-cell proteins (HCPs) clearance, HMW species, and yield. CA precipitation removes HCPs and some HMW species to the acceptable levels under the optimal conditions. The CA precipitation process is robust at 15-25°C. For all five mAbs tested in this study, the optimal CA concentration range is 0.5-1.0%, while the pH range is from 5.0 to 6.0. A purification process using two chromatography steps (protein A capture column and ion exchange polishing column) in combination with CA-based impurity precipitation step can be used as a robust downstream process for mAb molecules with a broad range of isoelectric points. Residual CA can be effectively removed by the subsequent polishing cation exchange chromatography.

  1. Changes in soil bacterial communities induced by the invasive plant Pennisetum setaceum in a semiarid environment

    NASA Astrophysics Data System (ADS)

    Rodriguez-Caballero, Gema; Caravaca, Fuensanta; del Mar Alguacil, María; Fernández-López, Manuel; José Fernández-González, Antonio; García-Orenes, Fuensanta; Roldán, Antonio

    2016-04-01

    Invasive alien species are considered as a global threat being among the main causes of biodiversity loss. Plant invasions have been extensively studied from different disciplines with the purpose of identifying predictor traits of invasiveness and finding solutions. However, less is known about the implication of the rhizosphere microbiota in these processes, even when it is well known the importance of the interaction between plant rhizosphere and microbial communities. The objective of this study was to determine whether native and invasive plants support different bacterial communities in their rhizospheres and whether there are bacterial indicator species that might be contributing to the invasion process of these ecosystems. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum, an aggressive invasive Poaceae and soil bacterial communities were amplified and 454-pyrosequenced. Changes in the composition and structure of the bacterial communities, owing to the invasive status of the plant, were detected when the richness and alpha-diversity estimators were calculated as well as when we analyzed the PCoA axes scores. The Indicator Species Analysis results showed a higher number of indicators for invaded communities at all studied taxonomic levels. In conclusion, the effect of the invasiveness and its interaction with the soil location has promoted shifts in the rhizosphere bacterial communities which might be facilitating the invader success in these ecosystems.

  2. Gene expression regulation in retinal pigment epithelial cells induced by viral RNA and viral/bacterial DNA

    PubMed Central

    Brosig, Anton; Kuhrt, Heidrun; Wiedemann, Peter; Kohen, Leon; Bringmann, Andreas

    2015-01-01

    Purpose The pathogenesis of age-related macular degeneration (AMD) is associated with systemic and local inflammation. Various studies suggested that viral or bacterial infection may aggravate retinal inflammation in the aged retina. We compared the effects of synthetic viral RNA (poly(I:C)) and viral/bacterial DNA (CpG-ODN) on the expression of genes known to be involved in the development of AMD in retinal pigment epithelial (RPE) cells. Methods Cultured human RPE cells were stimulated with poly(I:C; 500 µg/ml) or CpG-ODN (500 nM). Alterations in gene expression and protein secretion were determined with real-time RT–PCR and ELISA, respectively. Phosphorylation of signal transduction molecules was revealed by western blotting. Results Poly(I:C) induced gene expression of the pattern recognition receptor TLR3, transcription factors (HIF-1α, p65/NF-κB), the angiogenic factor bFGF, inflammatory factors (IL-1β, IL-6, TNFα, MCP-1, MIP-2), and complement factors (C5, C9, CFB). Poly(I:C) also induced phosphorylation of ERK1/2 and p38 MAPK proteins, and the secretion of bFGF and TNFα from the cells. CpG-ODN induced moderate gene expression of transcription factors (p65/NF-κB, NFAT5) and complement factors (C5, C9), while it had no effect on the expression of various TLR, angiogenic factor, and inflammatory factor genes. The activities of various signal transduction pathways and transcription factors were differentially involved in mediating the poly(I:C)-induced transcriptional activation of distinct genes. Conclusions The widespread effects of viral RNA, and the restricted effects of viral/bacterial DNA, on the gene expression pattern of RPE cells may suggest that viral RNA rather than viral/bacterial DNA induces physiologic alterations of RPE cells, which may aggravate inflammation in the aged retina. The data also suggest that selective inhibition of distinct signal transduction pathways or individual transcription factors may not be effective to inhibit

  3. Metformin prevents the effects of Pseudomonas aeruginosa on airway epithelial tight junctions and restricts hyperglycaemia-induced bacterial growth.

    PubMed

    Patkee, Wishwanath R A; Carr, Georgina; Baker, Emma H; Baines, Deborah L; Garnett, James P

    2016-04-01

    Lung disease and elevation of blood glucose are associated with increased glucose concentration in the airway surface liquid (ASL). Raised ASL glucose is associated with increased susceptibility to infection by respiratory pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. We have previously shown that the anti-diabetes drug, metformin, reduces glucose-induced S. aureus growth across in vitro airway epithelial cultures. The aim of this study was to investigate whether metformin has the potential to reduce glucose-induced P. aeruginosa infections across airway epithelial (Calu-3) cultures by limiting glucose permeability. We also explored the effect of P. aeruginosa and metformin on airway epithelial barrier function by investigating changes in tight junction protein abundance. Apical P. aeruginosa growth increased with basolateral glucose concentration, reduced transepithelial electrical resistance (TEER) and increased paracellular glucose flux. Metformin pre-treatment of the epithelium inhibited the glucose-induced growth of P. aeruginosa, increased TEER and decreased glucose flux. Similar effects on bacterial growth and TEER were observed with the AMP activated protein kinase agonist, 5-aminoimidazole-4-carboxamide ribonucleotide. Interestingly, metformin was able to prevent the P. aeruginosa-induced reduction in the abundance of tight junction proteins, claudin-1 and occludin. Our study highlights the potential of metformin to reduce hyperglycaemia-induced P. aeruginosa growth through airway epithelial tight junction modulation, and that claudin-1 and occludin could be important targets to regulate glucose permeability across airway epithelia and supress bacterial growth. Further investigation into the mechanisms regulating metformin and P. aeruginosa action on airway epithelial tight junctions could yield new therapeutic targets to prevent/suppress hyperglycaemia-induced respiratory infections, avoiding the use of antibiotics.

  4. Rapid attribution of the August 2016 flood-inducing extreme precipitation in south Louisiana to climate change

    NASA Astrophysics Data System (ADS)

    van der Wiel, Karin; Kapnick, Sarah B.; van Oldenborgh, Geert Jan; Whan, Kirien; Philip, Sjoukje; Vecchi, Gabriel A.; Singh, Roop K.; Arrighi, Julie; Cullen, Heidi

    2017-02-01

    A stationary low pressure system and elevated levels of precipitable water provided a nearly continuous source of precipitation over Louisiana, United States (US), starting around 10 August 2016. Precipitation was heaviest in the region broadly encompassing the city of Baton Rouge, with a 3-day maximum found at a station in Livingston, LA (east of Baton Rouge), from 12 to 14 August 2016 (648.3 mm, 25.5 inches). The intense precipitation was followed by inland flash flooding and river flooding and in subsequent days produced additional backwater flooding. On 16 August, Louisiana officials reported that 30 000 people had been rescued, nearly 10 600 people had slept in shelters on the night of 14 August and at least 60 600 homes had been impacted to varying degrees. As of 17 August, the floods were reported to have killed at least 13 people. As the disaster was unfolding, the Red Cross called the flooding the worst natural disaster in the US since Super Storm Sandy made landfall in New Jersey on 24 October 2012. Before the floodwaters had receded, the media began questioning whether this extreme event was caused by anthropogenic climate change. To provide the necessary analysis to understand the potential role of anthropogenic climate change, a rapid attribution analysis was launched in real time using the best readily available observational data and high-resolution global climate model simulations. The objective of this study is to show the possibility of performing rapid attribution studies when both observational and model data and analysis methods are readily available upon the start. It is the authors' aspiration that the results be used to guide further studies of the devastating precipitation and flooding event. Here, we present a first estimate of how anthropogenic climate change has affected the likelihood of a comparable extreme precipitation event in the central US Gulf Coast. While the flooding event of interest triggering this study occurred in south

  5. Antibiotic exposure can induce various bacterial virulence phenotypes in multidrug-resistant Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is one of the most prevalent bacterial foodborne diseases in the United States and causes an estimated 1 million human cases every year. Multidrug-resistant (MDR) Salmonella has emerged as a public health issue as it has been associated with increased morbidity in humans and mortality in...

  6. Heat treatment induced bacterial changes in irrigation water and their implications for plant disease management.

    PubMed

    Hao, W; Hong, C X

    2014-05-01

    A new heat treatment for recycled irrigation water using 48 °C for 24 h to inactivate Phytophthora and bacterial plant pathogens is estimated to reduce fuel cost and environmental footprint by more than 50 % compared to current protocol (95 °C for 30 s). The objective of this study was to determine the impact of this new heat treatment temperature regime on bacterial community structure in water and its practical implications. Bacterial communities in irrigation water were analyzed before and after heat treatment using both culture-dependent and -independent strategies based on the 16S ribosomal DNA. A significant shift was observed in the bacterial community after heat treatment. Most importantly, bacteria with biological control potential--Bacillus and Paenibacillus, and Pseudomonas species became more abundant at both 48 and 42 °C. These findings imply that the new heat treatment procedure not only controls existing plant pathogens but also may make the heat-treated irrigation water a more antagonistic environment against plant pathogens, promoting sustainable disease management.

  7. Lipid II is an intrinsic component of the pore induced by nisin in bacterial membranes.

    PubMed

    Breukink, Eefjan; van Heusden, Hester E; Vollmerhaus, Pauline J; Swiezewska, Ewa; Brunner, Livia; Walker, Suzanne; Heck, Albert J R; de Kruijff, Ben

    2003-05-30

    The peptidoglycan layers surrounding bacterial membranes are essential for bacterial cell survival and provide an important target for antibiotics. Many antibiotics have mechanisms of action that involve binding to Lipid II, the prenyl chain-linked donor of the peptidoglycan building blocks. One of these antibiotics, the pore-forming peptide nisin uses Lipid II as a receptor molecule to increase its antimicrobial efficacy dramatically. Nisin is the first example of a targeted membrane-permeabilizing peptide antibiotic. However, it was not known whether Lipid II functions only as a receptor to recruit nisin to bacterial membranes, thus increasing its specificity for bacterial cells, or whether it also plays a role in pore formation. We have developed a new method to produce large amounts of Lipid II and variants thereof so that we can address the role of the lipid-linked disaccharide in the activity of nisin. We show here that Lipid II is not only the receptor for nisin but an intrinsic component of the pore formed by nisin, and we present a new model for the pore complex that includes Lipid II.

  8. Adsorption Isotherms: North Caroline Apatite Induced Precipitation of Lead, Zinc, Manganese, and Cadmium from the Bunker Hill 4000 Soil

    DTIC Science & Technology

    1995-05-01

    Using the MINTEQ -A2 geochemical model, thermodynamic predictions for ^f0™«0™0? pyromorphytes (Pb5(POJ3 (OH, Cl)), hopeite (Zn3(POJ2 4H20...VERIFICATION OF PRECIPITATED METALS USING MINTEQ -A2 13 2.3.1 Experimental 2.3.2 Results ... 19 3.0 CONCLUSIONS 20 4.0...precipitated Pb-P04 complexes will be illustrated as sharp downward deviations from linearity of the adsorption isotherms, as predicted by MINTEQ -A2

  9. Precipitation Recycling

    NASA Technical Reports Server (NTRS)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1996-01-01

    The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

  10. Grain-rich diets altered the colonic fermentation and mucosa-associated bacterial communities and induced mucosal injuries in goats

    PubMed Central

    Ye, Huimin; Liu, Junhua; Feng, Panfei; Zhu, Weiyun; Mao, Shengyong

    2016-01-01

    Remarkably little information is available about the impact of high-grain (HG) feeding on colonic mucosa-associated bacteria and mucosal morphology. In the present study, 12 male goats were randomly assigned to either a hay diet (n = 6) or an HG diet (65% grain; n = 6) to characterise the changes in the composition of the bacterial community in colonic mucosa and the mucosal morphology of the colon. The results showed that HG feeding decreased the colonic pH and increased the concentrations of total short chain fatty acids and lipopolysaccharides in colonic digesta. The principal coordinate analysis results showed that the HG diet altered the colonic mucosal bacterial communities, with an increase in the abundance of genus Blautia and a decrease in the abundance of genera Bacillus, Enterococcus, and Lactococcus. The HG-fed goats showed sloughing of the surface layer epithelium, intercellular tight junction erosion, cell mitochondrial damage, and upregulation of the relative mRNA expression of IL-2 and IFN-γ in colonic mucosa. Collectively, our data indicate that HG feeding induced changes in colonic mucosal morphology and cytokines expression that might be caused by excessive fermentation and dramatic shifts in the bacterial populations in the colon. PMID:26841945

  11. STRONTIUM PRECIPITATION

    DOEpatents

    McKenzie, T.R.

    1960-09-13

    A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

  12. Lipopolysaccharide induces apoptosis in Carassius auratus lymphocytes, a possible role in pathogenesis of bacterial infection in fish.

    PubMed

    Xiang, Li-Xin; Peng, Bo; Dong, Wei-Ren; Yang, Zai-Feng; Shao, Jian-Zhong

    2008-01-01

    Lipopolysaccharide (LPS), the endotoxin of Gram-negative bacteria, is capable of eliciting a wide variety of pathophysiological effects, including endotoxin shock, tissue injury and lethality in both humans and animals. It is also a potent stimulant to initiate the proliferation, differentiation and activation of B lymphocytes and macrophages, resulting in changes of inflammatory cytokines, such as TNF-alpha, IL1-beta, IL6, IL-8 and IL-12, and enhancement of immune responses. However, little is known about its effect on the induction of apoptosis in lymphocytes. In the present study, the lymphocytes from Carassius auratus were employed for this purpose. The cells were exposed to LPS at various doses for different time periods. By careful apoptotic characteristic analysis, such as condensation of nuclear chromatin, fragmentation of genomic DNA and formation of apoptotic bodies, it provided the first evidence that LPS had apoptotic-inducing effect on fish lymphocytes in a time- and dose-dependent manner. LPS exposure induced significant increase of intracellular reactive oxygen species (ROS), loss of mitochondrial transmembrane potential (DeltaPsi), depletion of ATP production, down-regulation of Bcl-2 expression, up-regulation of Bax and mitochondrial NO-synthase (mNOS) expression, and selective activation of caspase-9 rather than caspase-8. Each of these observations suggests that the LPS-induced apoptosis in C. auratus lymphocytes occurs largely via the mitochondrial apoptotic pathway. This observation was different from the mechanism behind the LPS-induced apoptosis in mammalian macrophages/thymocytes that occurs via the TNF-alpha-mediated death-receptor pathway. Our study suggested the existence of a possible novel role in the pathogenesis of Gram-negative bacterial infection in fish and even in mammals, which may contribute to the therapy of bacterial diseases. Also, it will help to gain more insights into the mechanisms of septic shock and of LPS-induced

  13. Lighting-induced Electron Precipitation (LEP) Events versus Geomagnetic Activity: A Probe Tool to Re-Evaluate the Electron Radiation Belt Loss Mechanisms (P16)

    NASA Astrophysics Data System (ADS)

    Fernandez, J. H.; Raulin, J.-P.; Correia, E.; Brum, C. G. M.

    2006-11-01

    We present the first results of an incipient attempt to re-model the Van Allen electron radiation belts equilibrium mechanisms. During the 23rd cycle solar minimum period (1995-1997) the Lightning- induced Electron Precipitation (LEP) events (electron precipitation from the geo-space to the upper Earth atmosphere) occurrence at the Antarctica Peninsula region was collected and studied. With statistical techniques we have reproduced the pattern of the events incidence during that period. The year 1998 was also analyzed and two well-defined geomagnetic storms (01-07 May and 26-31 Aug) were studied in association with the Trimpi events data. We have confirmed the narrow relationship between events occurrence rate and geomagnetic activity. The next step, in order to carry on the model, will be the modeling of the solar maximum LEP occurrence and to compute these results in the present radiation belts population models.

  14. Laser induced shockwaves on flexible polymers for treatment of bacterial biofilms.

    PubMed

    Navarro, Artemio; Taylor, Zachary D; Beenhouwer, David; Haake, David A; Gupta, Vijay; Grundfest, Warren S

    2011-01-01

    Bacterial biofilm-related infections are a burden on the healthcare industry. The effect of laser generated shockwaves through polycarbonate, a flexible polymer, is explored for its ability to generate high peak stresses, and also for its ability to conform to complex wound surfaces. Shockwave pulses in Al coated polycarbonate substrates and a resulting peak stress of greater than 60 MPa was measured which should provide sufficient pressure to kill bacteria.

  15. Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

    PubMed Central

    Kidd, Petra; Kuffner, Melanie; Prieto-Fernández, Ángeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

    2013-01-01

    The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

  16. Finding immune gene expression differences induced by marine bacterial pathogens in the deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    NASA Astrophysics Data System (ADS)

    Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.

    2013-02-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterized by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio strains. Flavobacterium suspensions were also used as an irrelevant bacterium. Gene expression analyses were carried out using gill samples from animals dissected at 12 h and 24 h post-infection times by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h and 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the microorganism species inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly around a protein area, of 18 KDa molecular mass, where most dissimilarities were found. Multivariate analyses

  17. Finding immune gene expression differences induced by marine bacterial pathogens in the Deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    NASA Astrophysics Data System (ADS)

    Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.

    2013-11-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterised by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio bacteria. Flavobacterium suspensions were also used as a non-pathogenic bacterium. Gene expression analyses were carried out using gill samples from infected animals by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h to 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the bacterium inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly evident for proteins of 18-20 KDa molecular mass, where most dissimilarity was found. Multivariate analyses demonstrated that immune genes, as well as experimental

  18. Oral mucosal lipids are antibacterial against Porphyromonas gingivalis, induce ultrastructural damage, and alter bacterial lipid and protein compositions.

    PubMed

    Fischer, Carol L; Walters, Katherine S; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

    2013-09-01

    Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria; however, little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria. In this study, we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Minimal inhibitory concentrations, minimal bactericidal concentrations, and kill kinetics revealed variable, but potent, activity of oral mucosal and salivary lipids against P. gingivalis, indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria, although specific components of bacterial membranes are also likely important. Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane. This information, coupled with the association of treatment lipids with P. gingivalis lipids revealed via thin layer chromatography, suggests that the plasma membrane is a likely target of lipid antibacterial activity. Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P. gingivalis stress response, including proteins important in fatty acid biosynthesis, metabolism and energy production, protein processing, cell adhesion and virulence. Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces.

  19. Oral mucosal lipids are antibacterial against Porphyromonas gingivalis, induce ultrastructural damage, and alter bacterial lipid and protein compositions

    PubMed Central

    Fischer, Carol L; Walters, Katherine S; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

    2013-01-01

    Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria; however, little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria. In this study, we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Minimal inhibitory concentrations, minimal bactericidal concentrations, and kill kinetics revealed variable, but potent, activity of oral mucosal and salivary lipids against P. gingivalis, indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria, although specific components of bacterial membranes are also likely important. Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane. This information, coupled with the association of treatment lipids with P. gingivalis lipids revealed via thin layer chromatography, suggests that the plasma membrane is a likely target of lipid antibacterial activity. Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P. gingivalis stress response, including proteins important in fatty acid biosynthesis, metabolism and energy production, protein processing, cell adhesion and virulence. Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces. PMID:23867843

  20. Hydroxytyrosol from tyrosol using hydroxyphenylacetic acid-induced bacterial cultures and evidence of the role of 4-HPA 3-hydroxylase.

    PubMed

    Liebgott, Pierre-Pol; Amouric, Agnès; Comte, Alexia; Tholozan, Jean-Luc; Lorquin, Jean

    2009-12-01

    Hydroxytyrosol (HTyr) is a potent natural antioxidant found in olive mill wastewaters. Bacterial conversion of 4-tyrosol (2-(4-hydroxyphenyl)-ethanol) to HTyr was reported in a limited number of bacterial species including Pseudomonas aeruginosa. In this work, we studied this conversion, taking as a model the newly isolated Halomonas sp. strain HTB24. It was first hypothesized that the enzyme responsible for 4-tyrosol hydroxylation in HTyr was a 4-hydroxyphenylacetic acid 3-hydroxylase (HPAH, EC 1.14.13.3), previously known to convert 4-hydroxyphenylacetic acid (4-HPA) into 3,4-dihydroxyphenylacetic acid (3,4-DHPA) in P. aeruginosa. Cloning and expression of hpaB (oxygenase component) and hpaC (reductase component) genes from P. aeruginosa confirmed this hypothesis. Furthermore, using cultures of HTB24 containing 4-tyrosol, it was shown that 4-HPA accumulation preceded 4-tyrosol hydroxylation. We further demonstrated that the synthesis of HPAH activity was induced by 4-HPA, with the latter compound being formed from 4-tyrosol oxidation by aryl-dehydrogenases. Interestingly, similar results were obtained with other 4-HPA-induced bacteria, including P. aeruginosa, Serratia marcescens, Escherichia coli, Micrococcus luteus and other Halomonas, thus demonstrating general hydroxylating activity of 4-tyrosol by the HPAH enzyme. E. coli W did not have aryl-dehydrogenase activity and hence were unable to oxidize 4-tyrosol to 4-HPA and HTyr to 3,4-DHPA, making this bacterium a good candidate for achieving better HTyr production.

  1. Two genes with similarity to bacterial response regulators are rapidly and specifically induced by cytokinin in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Brandstatter, I.; Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1998-01-01

    Cytokinins are central regulators of plant growth and development, but little is known about their mode of action. By using differential display, we identified a gene, IBC6 (for induced by cytokinin), from etiolated Arabidopsis seedlings, that is induced rapidly by cytokinin. The steady state level of IBC6 mRNA was elevated within 10 min by the exogenous application of cytokinin, and this induction did not require de novo protein synthesis. IBC6 was not induced by other plant hormones or by light. A second Arabidopsis gene with a sequence highly similar to IBC6 was identified. This IBC7 gene also was induced by cytokinin, although with somewhat slower kinetics and to a lesser extent. The pattern of expression of the two genes was similar, with higher expression in leaves, rachises, and flowers and lower transcript levels in roots and siliques. Sequence analysis revealed that IBC6 and IBC7 are similar to the receiver domain of bacterial two-component response regulators. This homology, coupled with previously published work on the CKI1 histidine kinase homolog, suggests that these proteins may play a role in early cytokinin signaling.

  2. Mechanisms of bacterial inactivation in the liquid phase induced by a remote RF cold atmospheric pressure plasma jet

    NASA Astrophysics Data System (ADS)

    van Gils, C. A. J.; Hofmann, S.; Boekema, B. K. H. L.; Brandenburg, R.; Bruggeman, P. J.

    2013-05-01

    A radio-frequency atmospheric pressure argon plasma jet is used for the inactivation of bacteria (Pseudomonas aeruginosa) in solutions. The source is characterized by measurements of power dissipation, gas temperature, absolute UV irradiance as well as mass spectrometry measurements of emitted ions. The plasma-induced liquid chemistry is studied by performing liquid ion chromatography and hydrogen peroxide concentration measurements on treated distilled water samples. Additionally, a quantitative estimation of an extensive liquid chemistry induced by the plasma is made by solution kinetics calculations. The role of the different active components of the plasma is evaluated based on either measurements, as mentioned above, or estimations based on published data of measurements of those components. For the experimental conditions being considered in this work, it is shown that the bactericidal effect can be solely ascribed to plasma-induced liquid chemistry, leading to the production of stable and transient chemical species. It is shown that HNO2, ONOO- and H2O2 are present in the liquid phase in similar quantities to concentrations which are reported in the literature to cause bacterial inactivation. The importance of plasma-induced chemistry at the gas-liquid interface is illustrated and discussed in detail.

  3. Precipitation Matters

    ERIC Educational Resources Information Center

    McDuffie, Thomas

    2007-01-01

    Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite…

  4. Probing Induced Structural Changes in Biomimetic Bacterial Cell Membrane Interactions with Divalent Cations

    SciTech Connect

    Holt, Allison M; Standaert, Robert F; Jubb, Aaron M; Katsaras, John; Johs, Alexander

    2017-01-01

    Biological membranes, formed primarily by the self-assembly of complex mixtures of phospholipids, provide a structured scaffold for compartmentalization and structural processes in living cells. The specific physical properties of phospholipid species present in a given membrane play a key role in mediating these processes. Phosphatidylethanolamine (PE), a zwitterionic lipid present in bacterial, yeast, and mammalian cell membranes, is exceptional. In addition to undergoing the standard lipid polymorphic transition between the gel and liquid-crystalline phase, it can also assume an unusual polymorphic state, the inverse hexagonal phase (HII). Divalent cations are among the factors that drive the formation of the HII phase, wherein the lipid molecules form stacked tubular structures by burying the hydrophilic head groups and exposing the hydrophobic tails to the bulk solvent. Most biological membranes contain a lipid species capable of forming the HII state suggesting that such lipid polymorphic structural states play an important role in structural biological processes such as membrane fusion. In this study, the interactions between Mg2+ and biomimetic bacterial cell membranes composed of PE and phosphatidylglycerol (PG) were probed using differential scanning calorimetry (DSC), small-angle x-ray scattering (SAXS), and fluorescence spectroscopy. The lipid phase transitions were examined at varying ratios of PE to PG and upon exposure to physiologically relevant concentrations of Mg2+. An understanding of these basic interactions enhances our understanding of membrane dynamics and how membrane-mediated structural changes may occur in vivo.

  5. Effect of Bioactive Primers on Bacterial-Induced Secondary Caries at the Tooth-Resin Interface.

    PubMed

    Kim, G E; Leme-Kraus, A A; Phansalkar, R; Viana, G; Wu, C; Chen, S-N; Pauli, G F; Bedran-Russo, Akb

    Secondary caries at the tooth-resin interface is the primary reason for replacement of resin composite restorations. The tooth-resin interface is formed by the interlocking of resin material with hydroxyapatite crystals in enamel and collagen mesh structure in dentin. Efforts to strengthen the tooth-resin interface have identified chemical agents with dentin collagen cross-linking potential and antimicrobial activities. The purpose of the present study was to assess protective effects of bioactive primer against secondary caries development around enamel and dentin margins of class V restorations, using an in vitro bacterial caries model. Class V composite restorations were prepared on 60 bovine teeth (n=15) with pretreatment of the cavity walls with control buffer solution, an enriched fraction of grape seed extract (e-GSE), 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide/N-hydroxysuccinimide, or chlorhexidine digluconate. After incubating specimens in a bacterial model with Streptococcus mutans for four days, dentin and enamel were assessed by fluorescence microscopy. Results revealed that only the naturally occurring product, e-GSE, significantly inhibited the development of secondary caries immediately adjacent to the dentin-resin interface, as indicated by the caries inhibition zone. No inhibitory effects were observed in enamel margins. The results suggest that the incorporation of e-GSE into components of the adhesive system may inhibit secondary caries and potentially contribute to the protection of highly vulnerable dentin-resin margins.

  6. Carbon dioxide and hydrogen sulfide associations with regional bacterial diversity patterns in microbially induced concrete corrosion.

    PubMed

    Ling, Alison L; Robertson, Charles E; Harris, J Kirk; Frank, Daniel N; Kotter, Cassandra V; Stevens, Mark J; Pace, Norman R; Hernandez, Mark T

    2014-07-01

    The microbial communities associated with deteriorating concrete corrosion fronts were characterized in 35 samples taken from wastewater collection and treatment systems in ten utilities. Bacterial communities were described using Illumina MiSeq sequencing of the V1V2 region of the small subunit ribosomal ribonucleic acid (SSU-rRNA) gene recovered from fresh corrosion products. Headspace gas concentrations (hydrogen sulfide, carbon dioxide, and methane), pore water pH, moisture content, and select mineralogy were tested for correlation to community outcomes and corrosion extent using pairwise linear regressions and canonical correspondence analysis. Corroding concrete was most commonly characterized by moisture contents greater than 10%, pore water pH below one, and limited richness (<10 taxa). Bacterial community composition was not correlated to geographic location when considered independently from other environmental factors. Corrosion was most severe in sites with high levels of hydrogen sulfide (>100 ppm) and carbon dioxide (>1%) gases, conditions which also were associated with low diversity biofilms dominated by members of the acidophilic sulfur-oxidizer genus Acidithiobacillus.

  7. Microbiological and pathological examination of fatal calf pneumonia cases induced by bacterial and viral respiratory pathogens.

    PubMed

    Szeredi, Levente; Jánosi, Szilárd; Pálfi, Vilmos

    2010-09-01

    The infectious origin of fatal cases of calf pneumonia was studied in 48 calves from 27 different herds on postmortem examination. Lung tissue samples were examined by pathological, histological, bacterial culture, virus isolation and immunohistochemical methods for the detection of viral and bacterial infections. Pneumonia was diagnosed in 47/48 cases and infectious agents were found in 40/47 (85%) of those cases. The presence of multiple respiratory pathogens in 23/40 (57.5%) cases indicated the complex origin of fatal calf pneumonia. The most important respiratory pathogens were Mannheimia-Pasteurella in 36/40 (90%) cases, followed by Arcanobacterium pyogenes in 16/40 (40%) cases, Mycoplasma bovis in 12/40 (30%) cases, and bovine respiratory syncytial virus in 4/40 (10%) cases. Histophilus somni was detected in 2/40 (5%) cases, while bovine herpesvirus-1, bovine viral diarrhoea virus and parainfluenza virus-3 were each found in 1/40 (2.5%) case. Mastadenovirus, bovine coronavirus, influenza A virus or Chlamydiaceae were not detected.

  8. Impact of CO2-Induced Warming on Simulated Hurricane Intensity and Precipitation: Sensitivity to the Choice of Climate Model and Convective Parameterization.

    NASA Astrophysics Data System (ADS)

    Knutson, Thomas R.; Tuleya, Robert E.

    2004-09-01

    Previous studies have found that idealized hurricanes, simulated under warmer, high-CO2 conditions, are more intense and have higher precipitation rates than under present-day conditions. The present study explores the sensitivity of this result to the choice of climate model used to define the CO2-warmed environment and to the choice of convective parameterization used in the nested regional model that simulates the hurricanes. Approximately 1300 five-day idealized simulations are performed using a higher-resolution version of the GFDL hurricane prediction system (grid spacing as fine as 9 km, with 42 levels). All storms were embedded in a uniform 5 m s-1 easterly background flow. The large-scale thermodynamic boundary conditions for the experiments— atmospheric temperature and moisture profiles and SSTs—are derived from nine different Coupled Model Intercomparison Project (CMIP2+) climate models. The CO2-induced SST changes from the global climate models, based on 80-yr linear trends from +1% yr-1 CO2 increase experiments, range from about +0.8° to +2.4°C in the three tropical storm basins studied. Four different moist convection parameterizations are tested in the hurricane model, including the use of no convective parameterization in the highest resolution inner grid. Nearly all combinations of climate model boundary conditions and hurricane model convection schemes show a CO2-induced increase in both storm intensity and near-storm precipitation rates. The aggregate results, averaged across all experiments, indicate a 14% increase in central pressure fall, a 6% increase in maximum surface wind speed, and an 18% increase in average precipitation rate within 100 km of the storm center. The fractional change in precipitation is more sensitive to the choice of convective parameterization than is the fractional change of intensity. Current hurricane potential intensity theories, applied to the climate model environments, yield an average increase of intensity

  9. A model for microbially induced precipitation of vadose-zone calcites in fractures at LOS Alamos, New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Newman, Brent D.; Campbell, Andrew R.; Norman, David I.; Ringelberg, David B.

    1997-05-01

    Fractures are unique environments that can concentrate the flow of water, nutrients, and contaminants. As such, fractures play an important role in controlling the flux of various substances into and through the vadose zone. Calcite fracture fillings are present in the near surface in the Bandelier Tuff Formation at Los Alamos, New Mexico, and provide a record of the geochemical and hydrologic processes that have occurred in fractures. The objective of this study was to examine calcite fracture fills in order to improve understanding of processes within fractures, and in particular those that lead to precipitation of calcite. Samples of calcite fillings were collected from vertical and horizontal fractures exposed in a shallow waste-burial pit. Scanning electron microscopy show morphologies which suggest that plants, fungi, and bacteria were important in the precipitation process. Quadrupole mass spectrometric analyses of fluid inclusion gases show predominantly methane (17-99%) and little to no oxygen (0-8%), suggesting the development of anaerobic conditions in the fractures. Ester-linked phospholipid biomarkers are evidence for a diverse microbial community in the fractures, and the presence of di-ether lipids indicate that the methane was generated by anaerobic bacteria. The calcite fillings apparently resulted from multiple biological and chemical processes in which plant roots in the fractures were converted to calcite. Roots grew into the fractures, eventually died, and were decomposed by bacteria and fungi. Anaerobic gases were generated from encapsulated organic material within the calcite via microbial decomposition, or were generated by microbes simultaneously with calcite precipitation. It is likely that the biological controls on calcite formation that occurred in the Los Alamos fractures also occurs in soils, and may explain the occurrence of other types of pedogenic calcites.

  10. Reducing endocannabinoid metabolism with the fatty acid amide hydrolase inhibitor, URB597, fails to modify reinstatement of morphine-induced conditioned floor preference and naloxone-precipitated morphine withdrawal-induced conditioned floor avoidance.

    PubMed

    McCallum, Amanda L; Limebeer, Cheryl L; Parker, Linda A

    2010-10-01

    The potential of the fatty acid amide hydrolase (FAAH) inhibitor, URB597, to modify drug prime-induced reinstatement of morphine-induced conditioned floor preference or naloxone-precipitated morphine withdrawal-induced conditioned floor avoidance was evaluated. In Experiment 1, morphine-induced conditioned floor preference was established across 4 conditioning trials. Following extinction training (4 trials), rats were pretreated with URB597 or vehicle prior to a morphine prime or a saline prime. Morphine reinstated the previously extinguished floor preference, but URB597 did not modify the strength of the reinstated preference. In Experiment 2, naloxone-precipitated morphine withdrawal-induced conditioned floor avoidance was established across 2 conditioning trials. Following extinction training (14 trials), rats were pretreated with URB597 or vehicle prior to a saline prime or a morphine withdrawal prime. The morphine withdrawal prime reinstated the previously extinguished floor avoidance, but URB597 did not modify the strength of reinstated avoidance. These results suggest that under the conditions in which URB597 promotes extinction (e.g., Manwell et al. (2009)) it does not interfere with drug-induced reinstatement of either conditioned floor preference or avoidance. That is, although activation of the endocannabinoid (eCB) system promotes extinction of aversive learning, it may not prevent reinstatement of that aversion by re-exposure to the aversive treatment.

  11. Polycyclic Aromatic Hydrocarbon-Induced Changes in Bacterial Community Structure under Anoxic Nitrate Reducing Conditions

    PubMed Central

    Martirani-Von Abercron, Sophie-Marie; Pacheco, Daniel; Benito-Santano, Patricia; Marín, Patricia; Marqués, Silvia

    2016-01-01

    Although bacterial anaerobic degradation of mono-aromatic compounds has been characterized in depth, the degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene has only started to be understood in sulfate reducing bacteria, and little is known about the anaerobic degradation of PAHs in nitrate reducing bacteria. Starting from a series of environments which had suffered different degrees of hydrocarbon pollution, we used most probable number (MPN) enumeration to detect and quantify the presence of bacterial communities able to degrade several PAHs using nitrate as electron acceptor. We detected the presence of a substantial nitrate reducing community able to degrade naphthalene, 2-methylnaphthalene (2MN), and anthracene in some of the sites. With the aim of isolating strains able to degrade PAHs under denitrifying conditions, we set up a series of enrichment cultures with nitrate as terminal electron acceptor and PAHs as the only carbon source and followed the changes in the bacterial communities throughout the process. Results evidenced changes attributable to the imposed nitrate respiration regime, which in several samples were exacerbated in the presence of the PAHs. The presence of naphthalene or 2MN enriched the community in groups of uncultured and poorly characterized organisms, and notably in the Acidobacteria uncultured group iii1-8, which in some cases was only a minor component of the initial samples. Other phylotypes selected by PAHs in these conditions included Bacilli, which were enriched in naphthalene enrichments. Several nitrate reducing strains showing the capacity to grow on PAHs could be isolated on solid media, although the phenotype could not be reproduced in liquid cultures. Analysis of known PAH anaerobic degradation genes in the original samples and enrichment cultures did not reveal the presence of PAH-related nmsA-like sequences but confirmed the presence of bssA-like genes related to anaerobic toluene degradation

  12. Differential neutrophil responses to bacterial stimuli: Streptococcal strains are potent inducers of heparin-binding protein and resistin-release.

    PubMed

    Snäll, Johanna; Linnér, Anna; Uhlmann, Julia; Siemens, Nikolai; Ibold, Heike; Janos, Marton; Linder, Adam; Kreikemeyer, Bernd; Herwald, Heiko; Johansson, Linda; Norrby-Teglund, Anna

    2016-02-18

    Neutrophils are critical for the control of bacterial infections, but they may also contribute to disease pathology. Here we explore neutrophil responses, in particular the release of sepsis-associated factors heparin-binding protein (HBP) and resistin in relation to specific bacterial stimuli and sepsis of varying aetiology. Analyses of HBP and resistin in plasma of septic patients revealed elevated levels as compared to non-infected critically ill patients. HBP and resistin correlated significantly in septic patients, with the strongest association seen in group A streptococcal (GAS) cases. In vitro stimulation of human neutrophils revealed that fixed streptococcal strains induced significantly higher release of HBP and resistin, as compared to Staphylococcus aureus or Escherichia coli. Similarly, neutrophils stimulated with the streptococcal M1-protein showed a significant increase in co-localization of HBP and resistin positive granules as well as exocytosis of these factors, as compared to LPS. Using a GAS strain deficient in M1-protein expression had negligible effect on neutrophil activation, while a strain deficient in the stand-alone regulator MsmR was significantly less stimulatory as compared to its wild type strain. Taken together, the findings suggest that the streptococcal activation of neutrophils is multifactorial and involves, but is not limited to, proteins encoded by the FCT-locus.

  13. A New Pharmacological Agent (AKB-4924) Stabilizes Hypoxia Inducible Factor (HIF) and Increases Skin Innate Defenses Against Bacterial Infection

    PubMed Central

    Okumura, Cheryl Y.M.; Hollands, Andrew; Tran, Dan N.; Olson, Joshua; Dahesh, Samira; von Köckritz-Blickwede, Maren; Thienphrapa, Wdee; Corle, Courtney; Jeung, Seung Nam; Kotsakis, Anna; Shalwitz, Robert A.; Johnson, Randall S.; Nizet, Victor

    2013-01-01

    Hypoxia inducible factor-1 (HIF-1) is a transcription factor that is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. HIF-1 is also activated in response to bacterial pathogens and supports the innate immune response of both phagocytes and keratinocytes. In this work, we show that a new pharmacological compound AKB-4924 (Akebia Therapeutics) increases HIF-1α levels and enhances the antibacterial activity of phagocytes and keratinocytes against both methicillin-sensitive and -resistant strains of Staphylococcus aureus in vitro. AKB-4924 is also effective in stimulating the killing capacity of keratinocytes against the important opportunistic skin pathogens Pseudomonas aeruginosa and Acinitobacter baumanii. The effect of AKB-4924 is mediated through the activity of host cells, as the compound exerts no direct antimicrobial activity. Administered locally as a single agent, AKB-4924 limits S. aureus proliferation and lesion formation in a mouse skin abscess model. This approach to pharmacologically boost the innate immune response via HIF-1 stabilization may serve as a useful adjunctive treatment for antibiotic-resistant bacterial infections. PMID:22371073

  14. Rhizosphere bacterial community composition responds to arbuscular mycorrhiza, but not to reductions in microbial activity induced by foliar cutting.

    PubMed

    Vestergård, Mette; Henry, Frédéric; Rangel-Castro, Juan Ignacio; Michelsen, Anders; Prosser, James I; Christensen, Søren

    2008-04-01

    Differences in bacterial community composition (BCC) between bulk and rhizosphere soil and between rhizospheres of different plant species are assumed to be strongly governed by quantitative and qualitative rhizodeposit differences. However, data on the relationship between rhizodeposit amounts and BCC are lacking. Other soil microorganisms, e.g. arbuscular mycorrhizal fungi (AMF), may also influence BCC. We simulated foliar herbivory (cutting) to reduce belowground carbon allocation and rhizodeposition of pea plants grown either with or without AMF. This reduced soil respiration, rhizosphere microbial biomass and bacteriovorous protozoan abundance, whereas none of these were affected by AMF. After labelling plants with (13)CO(2), root and rhizosphere soil (13)C enrichment of cut plants were reduced to a higher extent (24-46%) than shoot (13)C enrichment (10-24%). AMF did not affect (13)C enrichment. Despite these clear indications of reduced rhizosphere carbon-input, denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes PCR-amplified targeting DNA and RNA from rhizosphere soil did not reveal any effects of cutting on banding patterns. In contrast, AMF induced consistent differences in both DNA- and RNA-based DGGE profiles. These results show that a reduction in rhizosphere microbial activity is not necessarily accompanied by changes in BCC, whereas AMF presence inhibits proliferation of some bacterial taxa while stimulating others.

  15. A model for the influence of microstructure, precipitate pinning and fission gas behavior on irradiation-induced recrystallization of nuclear fuels

    NASA Astrophysics Data System (ADS)

    Rest, J.

    2004-03-01

    Irradiation-induced recrystallization appears to be a general phenomenon in that it is observed to occur in a variety of nuclear fuel types, e.g. U-xMo, UO2, and U3O8. For temperatures below that where significant thermal annealing of defects occurs, an expression is derived for the fission density at which irradiation-induced recrystallization is initiated that is athermal and weakly dependent on fission rate. The initiation of recrystallization is to be distinguished from the subsequent progression and eventual consumption of the original fuel grain. The formulation takes into account the observed microstructural evolution of the fuel, the role of precipitate pinning and fission gas bubbles, and the triggering event for recrystallization. The calculated dislocation density, fission gas bubble-size distribution, and fission density at which recrystallization first appears are compared to measured quantities.

  16. Induced Bacterial Cross-Resistance toward Host Antimicrobial Peptides: A Worrying Phenomenon

    PubMed Central

    Fleitas, Osmel; Franco, Octávio L.

    2016-01-01

    Bacterial resistance to conventional antibiotics has reached alarming levels, threatening to return to the pre-antibiotic era. Therefore, the search for new antimicrobial compounds that overcome the resistance phenomenon has become a priority. Antimicrobial peptides (AMPs) appear as one of the most promising antibiotic medicines. However, in recent years several AMP-resistance mechanisms have been described. Moreover, the AMP-resistance phenomenon has become more complex due to its association with cross-resistance toward AMP effectors of the host innate immune system. In this context, the use of AMPs as a therapeutic option could be potentially hazardous, since bacteria could develop resistance toward our innate immune system. Here, we review the findings of major studies that deal with the AMP cross-resistance phenomenon. PMID:27047486

  17. Induced Bacterial Cross-Resistance toward Host Antimicrobial Peptides: A Worrying Phenomenon.

    PubMed

    Fleitas, Osmel; Franco, Octávio L

    2016-01-01

    Bacterial resistance to conventional antibiotics has reached alarming levels, threatening to return to the pre-antibiotic era. Therefore, the search for new antimicrobial compounds that overcome the resistance phenomenon has become a priority. Antimicrobial peptides (AMPs) appear as one of the most promising antibiotic medicines. However, in recent years several AMP-resistance mechanisms have been described. Moreover, the AMP-resistance phenomenon has become more complex due to its association with cross-resistance toward AMP effectors of the host innate immune system. In this context, the use of AMPs as a therapeutic option could be potentially hazardous, since bacteria could develop resistance toward our innate immune system. Here, we review the findings of major studies that deal with the AMP cross-resistance phenomenon.

  18. Bacterial lipopolysaccharide induces osteoclast formation in RAW 264.7 macrophage cells

    SciTech Connect

    Islam, Shamima; Hassan, Ferdaus; Tumurkhuu, Gantsetseg; Dagvadorj, Jargalsaikhan; Koide, Naoki; Naiki, Yoshikazu; Mori, Isamu; Yoshida, Tomoaki; Yokochi, Takashi . E-mail: yokochi@aichi-med-u.ac.jp

    2007-08-24

    Lipopolysaccharide (LPS) is a potent bone resorbing factor. The effect of LPS on osteoclast formation was examined by using murine RAW 264.7 macrophage cells. LPS-induced the formation of multinucleated giant cells (MGC) in RAW 264.7 cells 3 days after the exposure. MGCs were positive for tartrate-resistant acid phosphatase (TRAP) activity. Further, MGC formed resorption pits on calcium-phosphate thin film that is a substrate for osteoclasts. Therefore, LPS was suggested to induce osteoclast formation in RAW 264.7 cells. LPS-induced osteoclast formation was abolished by anti-tumor necrosis factor (TNF)-{alpha} antibody, but not antibodies to macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-{kappa}B ligand (RANKL). TNF-{alpha} might play a critical role in LPS-induced osteoclast formation in RAW 264.7 cells. Inhibitors of NF-{kappa}B and stress activated protein kinase (SAPK/JNK) prevented the LPS-induced osteoclast formation. The detailed mechanism of LPS-induced osteoclast formation is discussed.

  19. Effect of acidic electrolyzed water-induced bacterial inhibition and injury in live clam (Venerupis philippinarum) and mussel (Mytilus edulis).

    PubMed

    Al-Qadiri, Hamzah M; Al-Holy, Murad A; Shiroodi, Setareh Ghorban; Ovissipour, Mahmoudreza; Govindan, Byju N; Al-Alami, Nivin; Sablani, Shyam S; Rasco, Barbara

    2016-08-16

    The effect of acidic electrolyzed water (AEW) on inactivating Escherichia coli O104:H4, Listeria monocytogenes, Aeromonas hydrophila, Vibrio parahaemolyticus and Campylobacter jejuni in laboratory contaminated live clam (Venerupis philippinarum) and mussel (Mytilus edulis) was investigated. The initial levels of bacterial contamination were: in clam 4.9 to 5.7log10CFU/g, and in mussel 5.1 to 5.5log10CFU/g. Two types of AEW were used for treatment time intervals of 1 and 2h: strong (SAEW) with an available chlorine concentration (ACC) of 20mg/L, pH=3.1, and an oxidation-reduction potential (ORP) of 1150mV, and weak (WAEW) at ACC of 10mg/L, pH=3.55 and ORP of 950mV. SAEW and WAEW exhibited significant inhibitory activity against inoculated bacteria in both shellfish species with significant differences compared to saline solutions treatments (1-2% NaCl) and untreated controls (0h). SAEW showed the largest inhibitory activity, the extent of reduction (log10CFU/g) ranged from 1.4-1.7 for E. coli O104:H4; 1.0-1.6 for L. monocytogenes; 1.3-1.6 for A. hydrophila; 1.0-1.5 for V. parahaemolyticus; and 1.5-2.2 for C. jejuni in both types of shellfish. In comparison, significantly (P<0.05) lower inhibitory effect of WAEW was achieved compared to SAEW, where the extent of reduction (log10CFU/g) ranged from 0.7-1.1 for E. coli O104:H4; 0.6-0.9 for L. monocytogenes; 0.6-1.3 for A. hydrophila; 0.7-1.3 for V. parahaemolyticus; and 0.8-1.9 for C. jejuni in both types of shellfish. Among all bacterial strains examined in this study, AEW induced less bacterial injury (~0.1-1.0log10CFU/g) and more inactivation effect. This study revealed that AEW (10-20mg/L ACC) could be used to reduce bacterial contamination in live clam and mussel, which may help control possible unhygienic practices during production and processing of shellfish without apparent changes in the quality of the shellfish.

  20. Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause

    NASA Astrophysics Data System (ADS)

    Kubota, Yuko; Omura, Yoshiharu

    2017-01-01

    By performing test particle simulations of relativistic electrons scattered by electromagnetic ion cyclotron (EMIC) rising tone emissions, we find a nonlinear scattering process named SLPA (Scattering at Low Pitch Angle) totally different from the nonlinear wave trapping. The nonlinear wave trapping, occurring for high pitch angles away from the loss cone, scatters some of resonant electrons to lower pitch angles, and a fraction of the electrons is further transported into the loss cone by SLPA after being released from the wave trapping. SLPA as well as the nonlinear wave trapping can work in any cases with proton band or helium band and inside or outside the plasmapause. We clarify that the combined scattering process causes significant depletion of the outer radiation belt. In the time evolution of an electron distribution observed locally in longitude, we find echoes of the electron depletion by the localized EMIC emissions. Monitoring fluxes of electrons being lost into the atmosphere in the wave generation region, we also find that efficient relativistic electron precipitation in several seconds. The characteristics of the precipitating electron flux as a function of kinetic energy vary significantly depending on the wave frequency range and the plasma density.

  1. Malaria-Induced NLRP12/NLRP3-Dependent Caspase-1 Activation Mediates Inflammation and Hypersensitivity to Bacterial Superinfection

    PubMed Central

    Ataide, Marco A.; Andrade, Warrison A.; Zamboni, Dario S.; Wang, Donghai; Souza, Maria do Carmo; Franklin, Bernardo S.; Elian, Samir; Martins, Flaviano S.; Pereira, Dhelio; Reed, George; Fitzgerald, Katherine A.; Golenbock, Douglas T.; Gazzinelli, Ricardo T.

    2014-01-01

    Cyclic paroxysm and high fever are hallmarks of malaria and are associated with high levels of pyrogenic cytokines, including IL-1β. In this report, we describe a signature for the expression of inflammasome-related genes and caspase-1 activation in malaria. Indeed, when we infected mice, Plasmodium infection was sufficient to promote MyD88-mediated caspase-1 activation, dependent on IFN-γ-priming and the expression of inflammasome components ASC, P2X7R, NLRP3 and/or NLRP12. Pro-IL-1β expression required a second stimulation with LPS and was also dependent on IFN-γ-priming and functional TNFR1. As a consequence of Plasmodium-induced caspase-1 activation, mice produced extremely high levels of IL-1β upon a second microbial stimulus, and became hypersensitive to septic shock. Therapeutic intervention with IL-1 receptor antagonist prevented bacterial-induced lethality in rodents. Similar to mice, we observed a significantly increased frequency of circulating CD14+CD16−Caspase-1+ and CD14dimCD16+Caspase-1+ monocytes in peripheral blood mononuclear cells from febrile malaria patients. These cells readily produced large amounts of IL-1β after stimulation with LPS. Furthermore, we observed the presence of inflammasome complexes in monocytes from malaria patients containing either NLRP3 or NLRP12 pyroptosomes. We conclude that NLRP12/NLRP3-dependent activation of caspase-1 is likely to be a key event in mediating systemic production of IL-1β and hypersensitivity to secondary bacterial infection during malaria. PMID:24453977

  2. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    PubMed

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  3. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  4. Matrix protein CCN1 induced by bacterial DNA and CpG ODN limits lung inflammation and contributes to innate immune homeostasis.

    PubMed

    Moon, H-G; Qin, Z; Quan, T; Xie, L; Dela Cruz, C S; Jin, Y

    2015-03-01

    To defend against pulmonary infections, lung epithelial cells are equipped with complex innate immunity closely linked to inflammation. Dysregulated innate immunity/inflammation leads to self-perpetuating lung injury. The CpG motif in bacterial DNA is one of the factors involved in bacterial infection-associated inflammation. Bacterial DNA and synthetic CpG oligonucleotide (ODN) induced CCN1 secretion from lung epithelial cells, functioning as a potential "braking" signal to prevent uncontrolled inflammatory responses. CpG ODN-induced endoplasmic reticulum (ER) stress resulted in Src-Y527 phosphorylation (pY527) and Src/CCN1 vWF domain dissociation. Src-Y527 activated caveolin-1 (cav-1) phosphorylation at Y14 and then modulated CCN1 secretion via pCav-1 interaction with the CCN1 IGFbp domain. Functionally, secreted CCN1 promoted anti-inflammatory cytokine interleukin (IL)-10 release from epithelial cells via integrin αVβ6-PKC, and this subsequently suppressed tumor necrosis factor (TNF)-α, macrophage inflammatory protein 2 (MIP-2)-2 secretion and neutrophil infiltration in the lungs. Collectively, bacterial DNA/CpG ODN-stimulated CCN1 secretion via the BiP/GRP78-Src(Y527)-JNK-Cav-1(Y14) pathway and CpG-induced CCN1 conferred anti-inflammatory roles. Our studies suggested a novel paradigm by which the lung epithelium maintains innate immune homeostasis after bacterial infection.

  5. Extracellular stimulation of VSIG4/complement receptor Ig suppresses intracellular bacterial infection by inducing autophagy.

    PubMed

    Kim, Kwang H; Choi, Beom K; Kim, Young H; Han, Chungyong; Oh, Ho S; Lee, Don G; Kwon, Byoung S

    2016-09-01

    VSIG4/CRIg (V-set and immunoglobulin domain containing 4) is a transmembrane receptor of the immunoglobulin superfamily that is expressed specifically on macrophages and mature dendritic cells. VSIG4 signaling accelerates phagocytosis of C3-opsonized bacteria, thereby efficiently clearing pathogens within macrophages. We found that VSIG4 signaling triggered by C3-opsonized Listeria (opLM) or by agonistic anti-VSIG4 monoclonal antibody (mAb) induced macrophages to form autophagosomes. VSIG4-induced autophagosomes were selectively colocalized with the intracellular LM while starvation-induced autophagosomes were not. Consistent with these results, the frequency of autophagosomes induced by infection with opLM was lower in VSIG4-deficient bone marrow-derived macrophages (BMDMs) than in WT BMDMs. Furthermore, when VSIG4 molecules were overexpressed in HeLa cells, which are non-macrophage cells, VSIG4 triggering led to efficient uptake of LM, autophagosome formation, and killing of the infected LM. These findings suggest that VSIG4 signaling not only promotes rapid phagocytosis and killing of C3-opsonized intracellular bacteria, as previously reported, but also induces autophagosome formation, eliminating the LM that have escaped from phagosomes. We conclude that VSIG4 signaling provides an anti-immune evasion mechanism that prevents the outgrowth of intracellular bacteria in macrophages.

  6. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling.

    PubMed

    Shikuma, Nicholas J; Antoshechkin, Igor; Medeiros, João M; Pilhofer, Martin; Newman, Dianne K

    2016-09-06

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control.

  7. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling

    PubMed Central

    Shikuma, Nicholas J.; Antoshechkin, Igor; Medeiros, João M.; Pilhofer, Martin; Newman, Dianne K.

    2016-01-01

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control. PMID:27551098

  8. Self-consistent Model of Magnetospheric Ring Current and Propagating Electromagnetic Ion Cyclotron Waves. 2. Wave Induced Ring Current Precipitation and Thermal Electron Heating

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Kozyra, J. U.; Liemohn, M. W.

    2007-01-01

    This paper continues presentation and discussion of the results from our new global self-consistent theoretical model of interacting ring current ions and propagating electromagnetic ion cyclotron waves [Khazanov et al., 2006]. To study the effects of electromagnetic ion cyclotron wave propagation and refraction on the wave induced ring current precipitation and heating of the thermal plasmaspheric electrons, we simulate the May 1998 storm. The main findings after a simulation can be summarized as follows. Firstly, the wave induced ring current precipitation exhibits quite a lot of fine structure, and is highly organized by location of the plasmapause gradient. The strongest fluxes of about 4 x 10(exp 6) (cm(raised dot) s(raised dot) sr(raised dot) (sup -1)) are observed during the maill and early recovery phases of the storm. The very interesting and probably more important finding is that in a number of cases the most intense precipitating fluxes are not connected to the most intense waves in simple manner. The characteristics of the wave power spectral density distribution over the wave normal angle are extremely crucial for the effectiveness of the ring current ion scattering. Secondly, comparison of the global proton precipitating patterns with the results from RAM [Kozyra et al., 1997a] reveals that although we observe a qualitative agreement between the localizations of the wave induced precipitations in the models, there is no quantitative agreement between the magnitudes of the fluxes. The quantitative differences are mainly due to a qualitative difference between the characteristics of the wave power spectral density distributions over the wave normal angle in RAM and in our model. Thirdly, the heat fluxes to plasmaspheric electrons caused by Landau resonate energy absorption from electromagnetic ion cyclotron waves are observed in the postnoon-premidnight MLT sector, and can reach the magnitude of 10(exp 11) eV/(cm(sup 2)(raised dot)s). The Coulomb

  9. Model studies of short-term variations induced in trace gases by particle precipitation in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Fytterer, T.; Bender, S.; Berger, U.; Nieder, H.; Sinnhuber, M.; Wissing, J. M.

    2016-10-01

    The 3-D global chemistry and transport model (3dCTM) was used to investigate NO, OH, and O3 from January 2002 to May 2010 between 60 km and 133 km. Their daytime and nighttime mean zonal means (55°-75° geomagnetic latitude) were analyzed with respect to short-term variations associated with particle precipitation. The corresponding ionization rates were derived from the 3-D atmospheric ionization module Osnabrück (AIMOS), which is based on particle flux measurements. The trace gas variations with respect to their background were investigated by using a superposed epoch analysis. The 27 day signature associated with particle precipitation is found in NO, while it is only indicated in OH and O3 during winter. A varying solar spectrum associated with the 11 year solar cycle causes modifications of this signal up to 10%, while the main patterns are conserved. Published observations show a clear 27 day signal, qualitatively agreeing with the model results at altitudes >70 km except for O3 in Northern Hemisphere winter. Further differences occur with respect to the magnitude of the trace gas variations, primarily attributed to the different trace gas background and dynamical variations of the background atmosphere. Absolute OH variations are overestimated by the 3dCTM during winter, while the opposite is true for O3. These differences might originate from an unknown offset in AIMOS, incorrect chemical reaction rates, a different background of H2O and O3, and the model dynamics. However, their nonlinear relationship and their altitude of largest response are qualitatively captured in Southern Hemisphere winter.

  10. Mycobacterium avium MAV2054 protein induces macrophage apoptosis by targeting mitochondria and reduces intracellular bacterial growth

    PubMed Central

    Lee, Kang-In; Whang, Jake; Choi, Han-Gyu; Son, Yeo-Jin; Jeon, Haet Sal; Back, Yong Woo; Park, Hye-Soo; Paik, Seungwha; Park, Jeong-Kyu; Choi, Chul Hee; Kim, Hwa-Jung

    2016-01-01

    Mycobacterium avium complex induces macrophage apoptosis. However, the M. avium components that inhibit or trigger apoptosis and their regulating mechanisms remain unclear. We recently identified the immunodominant MAV2054 protein by fractionating M. avium culture filtrate protein by multistep chromatography; this protein showed strong immuno-reactivity in M. avium complex pulmonary disease and in patients with tuberculosis. Here, we investigated the biological effects of MAV2054 on murine macrophages. Recombinant MAV2054 induced caspase-dependent macrophage apoptosis. Enhanced reactive oxygen species production and JNK activation were essential for MAV2054-mediated apoptosis and MAV2054-induced interleukin-6, tumour necrosis factor, and monocyte chemoattractant protein-1 production. MAV2054 was targeted to the mitochondrial compartment of macrophages treated with MAV2054 and infected with M. avium. Dissipation of the mitochondrial transmembrane potential (ΔΨm) and depletion of cytochrome c also occurred in MAV2054-treated macrophages. Apoptotic response, reactive oxygen species production, and ΔΨm collapse were significantly increased in bone marrow-derived macrophages infected with Mycobacterium smegmatis expressing MAV2054, compared to that in M. smegmatis control. Furthermore, MAV2054 expression suppressed intracellular growth of M. smegmatis and increased the survival rate of M. smegmatis-infected mice. Thus, MAV2054 induces apoptosis via a mitochondrial pathway in macrophages, which may be an innate cellular response to limit intracellular M. avium multiplication. PMID:27901051

  11. Surfactant-induced bacterial community changes correlated with increased polycyclic aromatic hydrocarbon degradation in contaminated soil.

    PubMed

    Singleton, David R; Adrion, Alden C; Aitken, Michael D

    2016-12-01

    Bioremediation as a method for removing polycyclic aromatic hydrocarbons (PAHs) from contaminated environments has been criticized for poor removal of potentially carcinogenic but less bioavailable high molecular weight (HMW) compounds. As a partial remedy to this constraint, we studied surfactant addition at sub-micellar concentrations to contaminated soil to enhance the biodegradation of PAHs remaining after conventional aerobic bioremediation. We demonstrated increased removal of four- and five-ring PAHs using two nonionic surfactants, polyoxyethylene(4)lauryl ether (Brij 30) and polyoxyethylene sorbitol hexaoleate (POESH), and analyzed bacterial community shifts associated with those conditions. Eight groups of abundant bacteria were implicated as potentially being involved in increased HMW PAH removal. A group of unclassified Alphaproteobacteria and members of the Phenylobacterium genus in particular showed significantly increased relative abundance in the two conditions exhibiting increased PAH removal. Other implicated groups included members of the Sediminibacterium, Terrimonas, Acidovorax, and Luteimonas genera, as well as uncharacterized organisms within the families Chitinophagaceae and Bradyrhizobiaceae. Targeted isolation identified a subset of the community likely using the surfactants as a growth substrate, but few of the isolates exhibited PAH-degradation capability. Isolates recovered from the Acidovorax and uncharacterized Bradyrhizobiaceae groups suggest the abundance of those groups may have been attributable to growth on surfactants. Understanding the specific bacteria responsible for HMW PAH removal in natural and engineered systems and their response to stimuli such as surfactant amendment may improve bioremediation efficacy during treatment of contaminated environmental media.

  12. Bioengineering a bacterial pathogen to assemble its own particulate vaccine capable of inducing cellular immunity

    PubMed Central

    Lee, Jason W.; Parlane, Natalie A.; Wedlock, D. Neil; Rehm, Bernd H. A.

    2017-01-01

    Many bacterial pathogens naturally form cellular inclusions. Here the immunogenicity of polyhydroxyalkanoate (PHA) inclusions and their use as particulate vaccines delivering a range of host derived antigens was assessed. Our study showed that PHA inclusions of pathogenic Pseudomonas aeruginosa are immunogenic mediating a specific cell-mediated immune response. Protein engineering of the PHA inclusion forming enzyme by translational fusion of epitopes from vaccine candidates outer membrane proteins OprI, OprF, and AlgE mediated self-assembly of PHA inclusions coated by these selected antigens. Mice vaccinated with isolated PHA inclusions produced a Th1 type immune response characterized by antigen-specific production of IFN-γ and IgG2c isotype antibodies. This cell-mediated immune response was found to be associated with the production of functional antibodies reacting with cells of various P. aeruginosa strains as well as facilitating opsonophagocytic killing. This study showed that cellular inclusions of pathogenic bacteria are immunogenic and can be engineered to display selected antigens suitable to serve as particulate subunit vaccines against infectious diseases. PMID:28150705

  13. Selegiline modifies the extinction of responding following morphine self-administration, but does not alter cue-induced reinstatement, reacquisition of morphine reinforcement, or precipitated withdrawal.

    PubMed

    Grasing, Kenneth; He, Shaunteng; Li, Ning

    2005-01-01

    Selegiline is an irreversible inhibitor of monoamine oxidase (MAO) with psychostimulant and neuroprotective effects which can prevent decreases in dopamine efflux that follow opiate withdrawal. The present study evaluated effects of selegiline treatment on morphine-seeking behavior and morphine reinforcement in Wistar rats (n = 26). In additional animals (n = 30), the ability of single doses of selegiline to modify naloxone-precipitated withdrawal was determined. After pretreatment with noncontingent morphine to establish opiate dependence, rats acquired self-administration of intravenous morphine. Daily intravenous treatment with saline or 2.0mg kg(-1) doses of selegiline was then initiated and continued over 14 days during extinction, reinstatement, and reacquisition of morphine self-administration. To reduce the potential for psychostimulant effects, selegiline was administered approximately 1h following self-administration, extinction, or reinstatement sessions. In some animals (n = 23), effects of saline or selegiline administration on locomotor activity were determined following extinction sessions. Daily selegiline treatment decreased the number of ratios completed and increased response latency during extinction, without modifying these measures during reinstatement or reacquisition of morphine self-administration. Chronic selegiline treatment increased locomotor activity recorded between 4 and 7h after selegiline administration on day 7 of extinction, but otherwise did not alter locomotor activity. Pretreatment with single, 2.0mg kg(-1) doses of selegiline did not modify naloxone-precipitated withdrawal. In conclusion, pretreatment with selegiline produced only a small decrease in responding during extinction of morphine self-administration and did not modify cue-induced reinstatement of morphine-seeking behavior, reacquisition or morphine reinforcement, or precipitated withdrawal.

  14. Bilateral acute pyogenic conjunctivitis with iritis induced by unilateral topical application of bacterial peptidoglycan muramyl dipeptide in adult rabbits.

    PubMed

    Langford, Marlyn P; Foreman, Bridgett D; Srur, Lana; Ganley, James P; Redens, Thomas B

    2013-11-01

    The factors responsible for the conjunctivitis and iritis associated with acute ocular infection and post enteric inflammatory disease are not fully known. The pro-inflammatory activity of unilateral topical application of muramyl dipeptide (MDP; the smallest bio-active Gram-positive and Gram-negative bacterial cell wall component) was investigated in adult rabbits. The resultant bilateral conjunctivitis/iritis and pyogenic responses were characterized. Bilateral symptoms were graded by slit lamp examinations; tear fluid, Schirmer tests (tear production), blood and aqueous humor (AH) samples were obtained from MDP-treated and untreated rabbits. MDP concentration, gamma-glutamyltranspeptidase activity (GGT; key enzyme in glutathione recapture, xenobiotic detoxification, eicosanoid synthesis and neutrophil function), protein concentration, and tear cell density, cytology, and immunofluorescent antibody reactivity to GGT and calreticulin (CRT; MDP-binding protein) were determined. MDP was cleared from ipsilateral tears and serum by 6 h, but was undetected in mock-treated contralateral tears. Bilateral signs of acute transient pyogenic conjunctivitis, characterized by tearing, lid edema, conjunctival hyperemia, chemosis and leukocytic infiltrate with iritis (erythema and aqueous flare) were detected. Milder symptoms occurred in the mock-treated contralateral eyes. Bilateral symptoms, tear production, tear protein, GGT activity, and mucopurulent discharge (containing up to 2.5-5.0 × 10(6) cells/mL) were elevated 4-8 h post MDP and resolved to near pre-treatment levels by 24 h. Tear GGT activity and protein levels were higher in MDP-treated and mock-treated contralateral eyes than in eyes of untreated adult rabbits (p's < 0.001). Elevated tear GGT activity was associated with histopathology and increased vascular and epithelial permeability to serum protein, GGT-positive epithelia cells, macrophages and heterophils. Repeat MDP applications induced recurrent

  15. Synthetic ultrashort cationic lipopeptides induce systemic plant defense responses against bacterial and fungal pathogens.

    PubMed

    Brotman, Yariv; Makovitzki, Arik; Shai, Yechiel; Chet, Ilan; Viterbo, Ada

    2009-08-01

    A new family of synthetic, membrane-active, ultrashort lipopeptides composed of only four amino acids linked to fatty acids was tested for the ability to induce systemic resistance and defense responses in plants. We found that two peptides wherein the third residue is a d-enantiomer (italic), C16-KKKK and C16-KLLK, can induce medium alkalinization of tobacco suspension-cultured cells and expression of defense-related genes in cucumber and Arabidopsis seedlings. Moreover, these compounds can prime systemic induction of antimicrobial compounds in cucumber leaves similarly to the plant-beneficial fungus Trichoderma asperellum T203 and provide systemic protection against the phytopathogens Botrytis cinerea B05, Pseudomonas syringae pv. lachrimans, and P. syringae pv. tomato DC3000. Thus, short cationic lipopeptides are a new category of compounds with potentially high utility in the induction of systemic resistance in plants.

  16. Bacteria-induced or bacterial product-induced preterm parturition in mice and rabbits is preceded by a significant fall in serum progesterone concentrations.

    PubMed

    Fidel, P I; Romero, R; Maymon, E; Hertelendy, F

    1998-01-01

    Bacterial products are thought to induce labor by stimulating the production of pro-inflammatory cytokines and prostaglandins in gestational tissues, leading to the onset of preterm parturition. Progesterone withdrawal is a prerequisite of parturition in many species. Yet a role for progesterone in the mechanisms responsible for preterm parturition, in the setting of infection, is unclear. The current studies were conducted to determine if a fall in serum progesterone concentrations occurs before the onset of bacterial product-induced preterm parturition in animals. Accordingly, pregnant mice at day 15 (70% gestation) were injected i.p. with Escherichia coli lipopolysaccharide (LPS; 50 microg/mouse) and timed-pregnant rabbits were inoculated transcervically with a suspension of E. coli to cause an ascending intrauterine infection. Control animals in both groups received equal volumes of sterile phosphate-buffered saline (PBS) solution. Blood specimens were collected at regular intervals and serum progesterone levels were determined by RIA. Within 14 h of LPS administration, mice delivered their pups. The median concentrations of serum progesterone were significantly lower at 1 h, 4 h, 10 h, and at the onset of preterm parturition (11-12 h) after LPS injection, compared to that in animals given PBS. Similarly, E. coli-inoculated rabbits delivered 1-2 days posttranscervical inoculation and demonstrated 60% decrease in serum progesterone within 12-24 h of inoculation compared to those given PBS. Parturition in both control groups occurred at term, following typical progesterone withdrawal. It is concluded that LPS administration to pregnant mice and ascending intrauterine infection in pregnant rabbits is associated with a dramatic fall in serum progesterone concentrations prior to the onset of parturition.

  17. Thermal effects on microbial composition and microbiologically induced corrosion and mineral precipitation affecting operation of a geothermal plant in a deep saline aquifer.

    PubMed

    Lerm, Stephanie; Westphal, Anke; Miethling-Graff, Rona; Alawi, Mashal; Seibt, Andrea; Wolfgramm, Markus; Würdemann, Hilke

    2013-03-01

    The microbial diversity of a deep saline aquifer used for geothermal heat storage in the North German Basin was investigated. Genetic fingerprinting analyses revealed distinct microbial communities in fluids produced from the cold and warm side of the aquifer. Direct cell counting and quantification of 16S rRNA genes and dissimilatory sulfite reductase (dsrA) genes by real-time PCR proved different population sizes in fluids, showing higher abundance of bacteria and sulfate reducing bacteria (SRB) in cold fluids compared with warm fluids. The operation-dependent temperature increase at the warm well probably enhanced organic matter availability, favoring the growth of fermentative bacteria and SRB in the topside facility after the reduction of fluid temperature. In the cold well, SRB predominated and probably accounted for corrosion damage to the submersible well pump and iron sulfide precipitates in the near wellbore area and topside facility filters. This corresponded to lower sulfate content in fluids produced from the cold well as well as higher content of hydrogen gas that was probably released from corrosion, and maybe favored growth of hydrogenotrophic SRB. This study reflects the high influence of microbial populations for geothermal plant operation, because microbiologically induced precipitative and corrosive processes adversely affect plant reliability.

  18. Vacancy-induced dissolution of precipitates in out-of-equilibrium systems: A test case of Fe X (X =C ,N,O) alloys

    NASA Astrophysics Data System (ADS)

    Schuler, Thomas; Nastar, Maylise; Soisson, Frédéric

    2017-01-01

    Various out-of-equilibrium processes produce a supersaturation of vacancies in the material. When these defects show attractive binding energy with solutes, they will form stable point defect-solute clusters which will stabilize solutes in the solid solution with respect to the equilibrium case. Hence the out-of-equilibrium dynamic solubility limit increases, which can lead to the dissociation of solute precipitates. This vacancy-induced precipitate (VID) dissolution mechanism is an alternative to the well-known ballistic mixing effect (BAL) under irradiation, and it is also relevant for quenching, ball milling, and severe plastic deformation. Under irradiation, a BAL is efficient at low temperature only, whereas a VID is expected to be effective at intermediate temperatures. A quantitative and consistent prediction of the interstitial solute solubility limit increase generated by both BAL and VID mechanisms is presented starting from ab initio binding energies and migration energies of solutes and point defects, and using a low-temperature expansion of the free energy of the solid solution. These results are discussed for three alloys: FeC, FeN, and FeO, the latter being relevant to discuss the stability of oxide dispersed strengthened alloys microstructure under irradiation. We also suggest an experiment that would be able to determine steady-state vacancy supersaturations from the measure of solute partial pressures in out-of-equilibrium systems.

  19. Reliable solution processed planar perovskite hybrid solar cells with large-area uniformity by chloroform soaking and spin rinsing induced surface precipitation

    SciTech Connect

    Chern, Yann-Cherng; Wu, Hung-Ruei; Chen, Yen-Chu; Horng, Sheng-Fu; Zan, Hsiao-Wen; Meng, Hsin-Fei

    2015-08-15

    A solvent soaking and rinsing method, in which the solvent was allowed to soak all over the surface followed by a spinning for solvent draining, was found to produce perovskite layers with high uniformity on a centimeter scale and with much improved reliability. Besides the enhanced crystallinity and surface morphology due to the rinsing induced surface precipitation that constrains the grain growth underneath in the precursor films, large-area uniformity with film thickness determined exclusively by the rotational speed of rinsing spinning for solvent draining was observed. With chloroform as rinsing solvent, highly uniform and mirror-like perovskite layers of area as large as 8 cm × 8 cm were produced and highly uniform planar perovskite solar cells with power conversion efficiency of 10.6 ± 0.2% as well as much prolonged lifetime were obtained. The high uniformity and reliability observed with this solvent soaking and rinsing method were ascribed to the low viscosity of chloroform as well as its feasibility of mixing with the solvent used in the precursor solution. Moreover, since the surface precipitation forms before the solvent draining, this solvent soaking and rinsing method may be adapted to spinless process and be compatible with large-area and continuous production. With the large-area uniformity and reliability for the resultant perovskite layers, this chloroform soaking and rinsing approach may thus be promising for the mass production and commercialization of large-area perovskite solar cells.

  20. Precipitation hardening austenitic superalloys

    DOEpatents

    Korenko, Michael K.

    1985-01-01

    Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

  1. Automatic implantable cardiac defibrillator implantation may precipitate effort-induced thrombosis in young athletes: a case report and literature review.

    PubMed

    Wadhawan, Abhishek; Laage Gaupp, Fabian M; Sista, Akhilesh K

    2014-01-01

    Upper extremity deep vein thrombosis (DVT) is a common finding after implantation of an automatic implantable cardiac defrillator (AICD). We describe the case of a patient who developed a left upper extremity DVT 4.5 months after implantation of an AICD and was found to have a lead-induced stenosis with possible underlying Paget-Schroetter syndrome (PSS) in the midbrachiocephalic vein on venography. While his symptoms resolved after the combination of pharmacomechanical thrombolysis, angioplasty, and anticoagulation, his long-term management is complicated by the presence of both PSS and lead-induced stenosis. Herein, we discuss his presentation, treatment, and future management options.

  2. WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Hao, S. Z.; Zhang, Y.; Xu, Y.; Gey, N.; Grosdidier, T.; Dong, C.

    2013-11-01

    High current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 μs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC1-x, Co3W9C4, Co3W3C phases and graphite precipitate domains ˜50 nm. The friction coefficient of modified surface decreased to ˜0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 × 10-5 mm3/min to 6.3 × 10-6 mm3/min, showing a significant self-lubricating effect.

  3. Modeling the induced mutation process in bacterial cells with defects in excision repair system

    NASA Astrophysics Data System (ADS)

    Bugay, A. N.; Vasilyeva, M. A.; Krasavin, E. A.; Parkhomenko, A. Yu.

    2015-12-01

    A mathematical model of the UV-induced mutation process in Escherichia coli cells with defects in the uvrA and polA genes has been developed. The model describes in detail the reaction kinetics for the excision repair system. The number of mismatches as a result of translesion synthesis is calculated for both wild-type and mutant cells. The effect of temporal modulation of the number of single-stranded DNA during postreplication repair has been predicted. A comparison of effectiveness of different repair systems has been conducted.

  4. Intercomparison and coupling of magnesium-induced co-precipitation and long-path liquid-waveguide capillary cell techniques for trace analysis of phosphate in seawater.

    PubMed

    Li, Qian P; Hansell, Dennis A

    2008-03-17

    Currently, two common techniques for nanomolar-level phosphate measurements in seawater are magnesium-induced co-precipitation (MAGIC) and long-path liquid-waveguide capillary cell (LWCC) spectrophotometry. These techniques have been applied in the open ocean, and our understanding of phosphate distributions in oligotrophic subtropical gyres is based on those data. However, intercomparison of these methods has not previously been performed at nanomolar levels. Here, we report experimental results directly comparing the MAGIC and LWCC techniques. We also evaluated the impact of various commonly employed filters on phosphate determinations, as well as interferences from dissolved organic phosphorus (DOP) and arsenate. Our results find agreement between these methods at phosphate concentrations <100nM. We found that filter selection is important for accurate determinations of phosphate, and that DOP hydrolysis affects both techniques similarly. Finally, we demonstrate the advantage of combining MAGIC preconcentration and LWCC spectrophotometry for analysis of very low nanomolar concentrations.

  5. Antibiotic-induced dysbiosis alters host-bacterial interactions and leads to colonic sensory and motor changes in mice.

    PubMed

    Aguilera, M; Cerdà-Cuéllar, M; Martínez, V

    2015-01-01

    Alterations in the composition of the commensal microbiota (dysbiosis) seem to be a pathogenic component of functional gastrointestinal disorders, mainly irritable bowel syndrome (IBS), and might participate in the secretomotor and sensory alterations observed in these patients.We determined if a state antibiotics-induced intestinal dysbiosis is able to modify colonic pain-related and motor responses and characterized the neuro-immune mechanisms implicated in mice. A 2-week antibiotics treatment induced a colonic dysbiosis (increments in Bacteroides spp, Clostridium coccoides and Lactobacillus spp and reduction in Bifidobacterium spp). Bacterial adherence was not affected. Dysbiosis was associated with increased levels of secretory-IgA, up-regulation of the antimicrobial lectin RegIIIγ, and toll-like receptors (TLR) 4 and 7 and down-regulation of the antimicrobial-peptide Resistin-Like Molecule-β and TLR5. Dysbiotic mice showed less goblet cells, without changes in the thickness of the mucus layer. Neither macroscopical nor microscopical signs of inflammation were observed. In dysbiotic mice, expression of the cannabinoid receptor 2 was up-regulated, while the cannabinoid 1 and the mu-opioid receptors were down-regulated. In antibiotic-treated mice, visceral pain-related responses elicited by intraperitoneal acetic acid or intracolonic capsaicin were significantly attenuated. Colonic contractility was enhanced during dysbiosis. Intestinal dysbiosis induce changes in the innate intestinal immune system and modulate the expression of pain-related sensory systems, an effect associated with a reduction in visceral pain-related responses. Commensal microbiota modulates gut neuro-immune sensory systems, leading to functional changes, at least as it relates to viscerosensitivity. Similar mechanisms might explain the beneficial effects of antibiotics or certain probiotics in the treatment of IBS.

  6. Evaluation of the protective effect of pentoxifylline on carrageenan-induced chronic non-bacterial prostatitis in rats.

    PubMed

    Hajighorbani, Mahboobeh; Ahmadi-Hamedani, Mahmood; Shahab, Elaheh; Hayati, Farzad; Kafshdoozan, Khatereh; Keramati, Keivan; Amini, Amin Hossein

    2017-03-09

    Chronic non-bacterial prostatitis (CNP) is the most common type of prostatitis and oxidative stress (OS) was shown to be highly elevated in prostatitis patients. This study aimed to investigate the protective effect of pentoxifylline (PTX) on CNP induced by carrageenan in rats. Male adult Wistar rats (n = 30) were divided into control, CNP and three treatment groups (n = 6) including CNP + cernilton and CNP + PTX groups. CNP was induced by single intraprostatic injection of 1% carrageenan (100 µl). Rats in treatment groups received orally cernilton 100 mg/kg and PTX at 50 and 100 mg/kg 1 week after CNP induction for 21 days. Prostatic index (PI), prostatic specific antigen (PSA), tumor-necrosis factor alpha (TNF-α), serum lipid peroxidation (MDA), blood urea nitrogen, creatinine and histopathological changes were compared between groups. There were significant increase of PI, serum levels of PSA, TNF-α and MDA in CNP group at 29 day. In treatment groups, significant reduction in PI, serum levels of PSA, TNF-α, MDA and creatinine was observed especially in rats treated with dose of 50 mg/kg of PTX. In CNP group, histopathological changes of the prostate such as leucocyte infiltration, large involutions and projection into the lumen and reducing the volume of the lumen were observed as well. Whereas PTX, especially at dose of 50 mg/kg, could improve the above-mentioned changes remarkably in CNP treated rats. For the first time, our findings indicated that PTX improved CNP induced by carrageenan in rats.

  7. Antibiotic-induced dysbiosis alters host-bacterial interactions and leads to colonic sensory and motor changes in mice

    PubMed Central

    Aguilera, M; Cerdà-Cuéllar, M; Martínez, V

    2015-01-01

    Alterations in the composition of the commensal microbiota (dysbiosis) seem to be a pathogenic component of functional gastrointestinal disorders, mainly irritable bowel syndrome (IBS), and might participate in the secretomotor and sensory alterations observed in these patients.We determined if a state antibiotics-induced intestinal dysbiosis is able to modify colonic pain-related and motor responses and characterized the neuro-immune mechanisms implicated in mice. A 2-week antibiotics treatment induced a colonic dysbiosis (increments in Bacteroides spp, Clostridium coccoides and Lactobacillus spp and reduction in Bifidobacterium spp). Bacterial adherence was not affected. Dysbiosis was associated with increased levels of secretory-IgA, up-regulation of the antimicrobial lectin RegIIIγ, and toll-like receptors (TLR) 4 and 7 and down-regulation of the antimicrobial-peptide Resistin-Like Molecule-β and TLR5. Dysbiotic mice showed less goblet cells, without changes in the thickness of the mucus layer. Neither macroscopical nor microscopical signs of inflammation were observed. In dysbiotic mice, expression of the cannabinoid receptor 2 was up-regulated, while the cannabinoid 1 and the mu-opioid receptors were down-regulated. In antibiotic-treated mice, visceral pain-related responses elicited by intraperitoneal acetic acid or intracolonic capsaicin were significantly attenuated. Colonic contractility was enhanced during dysbiosis. Intestinal dysbiosis induce changes in the innate intestinal immune system and modulate the expression of pain-related sensory systems, an effect associated with a reduction in visceral pain-related responses. Commensal microbiota modulates gut neuro-immune sensory systems, leading to functional changes, at least as it relates to viscerosensitivity. Similar mechanisms might explain the beneficial effects of antibiotics or certain probiotics in the treatment of IBS. PMID:25531553

  8. A bacterial symbiont in the Bacteroidetes induces cytoplasmic incompatibility in the parasitoid wasp Encarsia pergandiella.

    PubMed Central

    Hunter, Martha S; Perlman, Steve J; Kelly, Suzanne E

    2003-01-01

    Vertically transmitted symbionts of arthropods have been implicated in several reproductive manipulations of their hosts. These include cytoplasmic incompatibility (CI), parthenogenesis induction in haplodiploid species (PI), feminization and male killing. One symbiont lineage in the alpha-Proteobacteria, Wolbachia, is the only bacterium known to cause all of these effects, and has been thought to be unique in causing CI, in which the fecundity of uninfected females is reduced after mating with infected males. Here, we provide evidence that an undescribed symbiont in the Bacteroidetes group causes CI in a sexual population of the parasitic wasp Encarsia pergandiella. Wasps were crossed in all four possible combinations of infected and uninfected individuals. In the cross predicted to be incompatible, infected (I) males x uninfected (U) females, progeny production was severely reduced, with these females producing only 12.6% of the number of progeny in other crosses. The incompatibility observed in this haplodiploid species was the female mortality type; dissections showed that most progeny from the incompatible cross died as eggs. The 16S rDNA sequence of this symbiont is 99% identical to a parthenogenesis-inducing symbiont in other Encarsia, and 96% identical to a feminizing symbiont in haplodiploid Brevipalpus mites. Thus, this recently discovered symbiont lineage is capable of inducing three of the four principal manipulations of host reproduction known to be caused by Wolbachia. PMID:14561283

  9. Stress-induced Condensation of Bacterial Genomes Results in Re-pairing of Sister Chromosomes

    PubMed Central

    Shechter, Nelia; Zaltzman, Liron; Weiner, Allon; Brumfeld, Vlad; Shimoni, Eyal; Fridmann-Sirkis, Yael; Minsky, Abraham

    2013-01-01

    Genome condensation is increasingly recognized as a generic stress response in bacteria. To better understand the physiological implications of this response, we used fluorescent markers to locate specific sites on Escherichia coli chromosomes following exposure to cytotoxic stress. We find that stress-induced condensation proceeds through a nonrandom, zipper-like convergence of sister chromosomes, which is proposed to rely on the recently demonstrated intrinsic ability of identical double-stranded DNA molecules to specifically identify each other. We further show that this convergence culminates in spatial proximity of homologous sites throughout chromosome arms. We suggest that the resulting apposition of homologous sites can explain how repair of double strand DNA breaks might occur in a mechanism that is independent of the widely accepted yet physiologically improbable genome-wide search for homologous templates. We claim that by inducing genome condensation and orderly convergence of sister chromosomes, diverse stress conditions prime bacteria to effectively cope with severe DNA lesions such as double strand DNA breaks. PMID:23884460

  10. The interplay between biological and physical scenarios of bacterial death induced by non-thermal plasma.

    PubMed

    Lunov, Oleg; Zablotskii, Vitalii; Churpita, Olexander; Jäger, Ales; Polívka, Leoš; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka

    2016-03-01

    Direct interactions of plasma matter with living cells and tissues can dramatically affect their functionality, initiating many important effects from cancer elimination to bacteria deactivation. However, the physical mechanisms and biochemical pathways underlying the effects of non-thermal plasma on bacteria and cell fate have still not been fully explored. Here, we report on the molecular mechanisms of non-thermal plasma-induced bacteria inactivation in both Gram-positive and Gram-negative strains. We demonstrate that depending on the exposure time plasma induces either direct physical destruction of bacteria or triggers programmed cell death (PCD) that exhibits characteristic features of apoptosis. The interplay between physical disruption and PCD is on the one hand driven by physical plasma parameters, and on the other hand by biological and physical properties of bacteria. The explored possibilities of the tuneable bacteria deactivation provide a basis for the development of advanced plasma-based therapies. To a great extent, our study opens new possibilities for controlled non-thermal plasma interactions with living systems.

  11. Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.

    SciTech Connect

    Ryan, S. D.; Haines, B. M.; Berlyand, L. V.; Ziebert, F.; Aranson, I. S.

    2011-05-01

    The viscosity of a suspension of swimming bacteria is investigated analytically and numerically. We propose a simple model that allows for efficient computation for a large number of bacteria. Our calculations show that long-range hydrodynamic interactions, intrinsic to self-locomoting objects in a viscous fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments on suspensions of Bacillus subtilis, we show that the viscosity reduction is related to the onset of large-scale collective motion due to interactions between the swimmers. The simulations reveal that the viscosity reduction occurs only for relatively low concentrations of swimmers: Further increases of the concentration yield an increase of the viscosity. We derive an explicit asymptotic formula for the effective viscosity in terms of known physical parameters and show that hydrodynamic interactions are manifested as self-induced noise in the absence of any explicit stochasticity in the system.

  12. Role of Bacterial Exopolysaccharides as Agents in Counteracting Immune Disorders Induced by Herpes Virus

    PubMed Central

    Gugliandolo, Concetta; Spanò, Antonio; Maugeri, Teresa L.; Poli, Annarita; Arena, Adriana; Nicolaus, Barbara

    2015-01-01

    Extreme marine environments, such as the submarine shallow vents of the Eolian Islands (Italy), offer an almost unexplored source of microorganisms producing unexploited and promising biomolecules for pharmaceutical applications. Thermophilic and thermotolerant bacilli isolated from Eolian vents are able to produce exopolysaccharides (EPSs) with antiviral and immunomodulatory effects against Herpes simplex virus type 2 (HSV-2). HSV-2 is responsible for the most common and continuously increasing viral infections in humans. Due to the appearance of resistance to the available treatments, new biomolecules exhibiting different mechanisms of action could provide novel agents for treating viral infections. The EPSs hinder the HSV-2 replication in human peripheral blood mononuclear cells (PBMC) but not in WISH (Wistar Institute Susan Hayflic) cells line, indicating that cell-mediated immunity was involved in the antiviral activity. High levels of Th1-type cytokines were detected in PBMC treated with all EPSs, while Th2-type cytokines were not induced. These EPSs are water soluble exopolymers able to stimulate the immune response and thus contribute to the antiviral immune defense, acting as immunomodulators. As stimulants of Th1 cell-mediated immunity, they could lead to the development of novel drugs as alternative in the treatment of herpes virus infections, as well as in immunocompromised host. PMID:27682100

  13. Aggregate formation in a freshwater bacterial strain induced by growth state and conspecific chemical cues.

    PubMed

    Blom, Judith F; Horňák, Karel; Simek, Karel; Pernthaler, Jakob

    2010-09-01

    We investigated the induction of aggregate formation in the freshwater bacterium Sphingobium sp. strain Z007 by growth state and protistan grazing. Dialysis bag batch culture experiments were conducted in which these bacteria were grown spatially separated from bacteria or from co-cultures of bacteria and predators. In pure cultures of Sphingobium sp. strain Z007, the concentrations of single cells and aggregates inside and outside the dialysis membranes developed in a similar manner over 3 days of incubation, and the proportions of aggregates were highest during the exponential growth phase. Cell production of Sphingobium sp. strain Z007 was enhanced in the presence of another isolate, Limnohabitans planktonicus, from an abundant freshwater lineage (R-BT065) outside the bags, and even more so if that strain was additionally grazed upon by the bacterivorous flagellate Poterioochromonas sp. However, the ratios of single cells to aggregates of Sphingobium sp. strain Z007 were not affected in either case. By contrast, the feeding of flagellates on Sphingobium sp. strain Z007 outside the dialysis bags led to significantly higher proportions of aggregates inside the bags. This was not paralleled by an increase in growth rates, and all cultures were in a comparable growth state at the end of the experiment. We conclude that two mechanisms, growth state and the possible release of infochemicals by the predator, may induce aggregate formation of Sphingobium sp. strain Z007. Moreover, these infochemicals only appeared to be generated by predation on cells from the same species.

  14. Activator of G-Protein Signaling 3-Induced Lysosomal Biogenesis Limits Macrophage Intracellular Bacterial Infection.

    PubMed

    Vural, Ali; Al-Khodor, Souhaila; Cheung, Gordon Y C; Shi, Chong-Shan; Srinivasan, Lalitha; McQuiston, Travis J; Hwang, Il-Young; Yeh, Anthony J; Blumer, Joe B; Briken, Volker; Williamson, Peter R; Otto, Michael; Fraser, Iain D C; Kehrl, John H

    2016-01-15

    Many intracellular pathogens cause disease by subverting macrophage innate immune defense mechanisms. Intracellular pathogens actively avoid delivery to or directly target lysosomes, the major intracellular degradative organelle. In this article, we demonstrate that activator of G-protein signaling 3 (AGS3), an LPS-inducible protein in macrophages, affects both lysosomal biogenesis and activity. AGS3 binds the Gi family of G proteins via its G-protein regulatory (GoLoco) motif, stabilizing the Gα subunit in its GDP-bound conformation. Elevated AGS3 levels in macrophages limited the activity of the mammalian target of rapamycin pathway, a sensor of cellular nutritional status. This triggered the nuclear translocation of transcription factor EB, a known activator of lysosomal gene transcription. In contrast, AGS3-deficient macrophages had increased mammalian target of rapamycin activity, reduced transcription factor EB activity, and a lower lysosomal mass. High levels of AGS3 in macrophages enhanced their resistance to infection by Burkholderia cenocepacia J2315, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus, whereas AGS3-deficient macrophages were more susceptible. We conclude that LPS priming increases AGS3 levels, which enhances lysosomal function and increases the capacity of macrophages to eliminate intracellular pathogens.

  15. Group B Streptococcus GAPDH Is Released upon Cell Lysis, Associates with Bacterial Surface, and Induces Apoptosis in Murine Macrophages

    PubMed Central

    Oliveira, Liliana; Madureira, Pedro; Andrade, Elva Bonifácio; Bouaboud, Abdelouhab; Morello, Eric; Ferreira, Paula; Poyart, Claire; Trieu-Cuot, Patrick; Dramsi, Shaynoor

    2012-01-01

    Glyceraldehyde 3-phosphate dehydrogenases (GAPDH) are cytoplasmic glycolytic enzymes that, despite lacking identifiable secretion signals, have been detected at the surface of several prokaryotic and eukaryotic organisms where they exhibit non-glycolytic functions including adhesion to host components. Group B Streptococcus (GBS) is a human commensal bacterium that has the capacity to cause life-threatening meningitis and septicemia in newborns. Electron microscopy and fluorescence-activated cell sorter (FACS) analysis demonstrated the surface localization of GAPDH in GBS. By addressing the question of GAPDH export to the cell surface of GBS strain NEM316 and isogenic mutant derivatives of our collection, we found that impaired GAPDH presence in the surface and supernatant of GBS was associated with a lower level of bacterial lysis. We also found that following GBS lysis, GAPDH can associate to the surface of many living bacteria. Finally, we provide evidence for a novel function of the secreted GAPDH as an inducer of apoptosis of murine macrophages. PMID:22291899

  16. Peptide-Lipid Interactions of the Stress-Response Peptide TisB That Induces Bacterial Persistence

    PubMed Central

    Steinbrecher, Thomas; Prock, Sebastian; Reichert, Johannes; Wadhwani, Parvesh; Zimpfer, Benjamin; Bürck, Jochen; Berditsch, Marina; Elstner, Marcus; Ulrich, Anne S.

    2012-01-01

    The bacterial stress-response peptide TisB in Escherichia coli has been suggested to dissipate the transmembrane potential, such that the depletion of ATP levels induces the formation of dormant persister cells which can eventually form biofilms. We studied the structure and membrane interactions of TisB to find out whether it forms pores or other proton-selective channels. Circular dichroism revealed an amphiphilic α-helical structure when reconstituted in lipid vesicles, and oriented circular dichroism showed that the helix assumes a transmembrane alignment. The addition of TisB to dye-loaded vesicles caused leakage only at very high peptide concentration, notably with a Hill coefficient of 2, which suggests that dimers must be involved. Coarse-grained molecular dynamics simulations showed that membrane binding of monomeric TisB is rapid and spontaneous, and transmembrane insertion is energetically feasible. When TisB oligomers are assembled as transmembrane pores, these channels collapse during the simulations, but transmembrane dimers are found to be stable. Given the pattern of charges on the amphiphilic TisB helix, we postulate that antiparallel dimers could be assembled via a ladder of salt bridges. This electrostatic charge-zipper could enable protons to pass along a wire of trapped water molecules across the hydrophobic membrane. PMID:23062338

  17. Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages

    PubMed Central

    Batista-Silva, L. R.; Rodrigues, Luciana Silva; Vivarini, Aislan de Carvalho; Costa, Fabrício da Mota Ramalho; Mattos, Katherine Antunes de; Costa, Maria Renata Sales Nogueira; Rosa, Patricia Sammarco; Toledo-Pinto, T. G.; Dias, André Alves; Moura, Danielle Fonseca; Sarno, Euzenir Nunes; Lopes, Ulisses Gazos; Pessolani, Maria Cristina Vidal

    2016-01-01

    Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis. PMID:27282338

  18. Sugar binding induces the same global conformational change in purified LacY as in the native bacterial membrane.

    PubMed

    Nie, Yiling; Kaback, H Ronald

    2010-05-25

    Many independent lines of evidence indicate that the lactose permease of Escherichia coli (LacY) is highly dynamic and that sugar binding causes closing of a large inward-facing cavity with opening of a wide outward-facing hydrophilic cavity. Therefore, lactose/H(+) symport catalyzed by LacY very likely involves a global conformational change that allows alternating access of single sugar- and H(+)-binding sites to either side of the membrane (the alternating access model). The x-ray crystal structures of LacY, as well as the majority of spectroscopic studies, use purified protein in detergent micelles. By using site-directed alkylation, we now demonstrate that sugar binding induces virtually the same global conformational change in LacY whether the protein is in the native bacterial membrane or is solubilized and purified in detergent. The results also indicate that the x-ray crystal structure reflects the structure of wild-type LacY in the native membrane in the absence of sugar.

  19. Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

    PubMed

    Mann, Rajinder S; Ali, Jared G; Hermann, Sara L; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S; Alborn, Hans T; Stelinski, Lukasz L

    2012-01-01

    Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace

  20. Differential expression of genes encoding calmodulin-binding proteins in response to bacterial pathogens and inducers of defense responses.

    PubMed

    Ali, Gul Shad; Reddy, Vaka S; Lindgren, Peter B; Jakobek, Judy L; Reddy, A S N

    2003-04-01

    Calmodulin (CaM) plays an important role in sensing and transducing changes in cellular Ca2+ concentration in response to several biotic and abiotic stresses. Although CaM is implicated in plant-pathogen interactions, its molecular targets and their role in defense signaling pathway(s) are poorly understood. To elucidate the signaling pathways that link CaM to defense responses, we screened a cDNA library constructed from bean leaves undergoing a hypersensitive response (HR) with radiolabeled CaM isoforms. A total of 26 putative CBPs were identified. Sequencing of the cDNAs revealed that they represent 8 different genes. They are homologues of previously identified CaM-binding proteins (CBPs) in other systems. However, some CBPs are novel members of known CBP families. The proteins encoded by these clones bound CaM in a Ca2+-dependent manner. To determine if these CBPs are involved in plant defense responses, we analyzed their expression in bean leaves inoculated with compatible, incompatible and nonpathogenic bacterial strains. Expression of three CBPs including an isoform of cyclic nucleotide-gated channels (PvCNGC-A) and two hypothetical proteins (PvCBP60-C and PvCBP60-D) was induced whereas the expression of two other isoforms of CNGCs (PvCNGC-B and PvCNGC-C) was repressed in response to incompatible pathogens. The expression of the rest, a small auxin up RNA (PvSAUR1) and two hypothetical proteins (PvCBP60-A and PvCBP60-B), was not changed. The expression of most of the pathogen-regulated genes was also affected by salicylic acid, jasmonic acid, hydrogen peroxide and a fungal elicitor, which are known to induce defense responses. Our results strongly suggest that at least five bean CBPs are involved in plant defense responses.

  1. Prevention of influenza virus induced bacterial superinfection by standardized Echinacea purpurea, via regulation of surface receptor expression in human bronchial epithelial cells.

    PubMed

    Vimalanathan, Selvarani; Schoop, Roland; Suter, Andy; Hudson, James

    2017-03-07

    Viral infections may predispose the airways to secondary bacterial infections that can lead to unfavorable progression of principally self-limiting illnesses. Such complicated respiratory infections include pneumonia, bronchitis, sinusitis, acute otitis media, and sepsis, which cause high morbidity and lethality. Some of the pathogenic consequences of viral infections, like the expression of bacterial adhesion receptors and the disturbance of physical barrier integrity due to inflammation, may create permissive conditions for co-infections. Influenza virus A (H3N2) is a major pathogen that causes secondary bacterial infections and inflammation that lead to pneumonia. The herbal medicine Echinacea purpurea, on the other hand, has been widely used to prevent and treat viral respiratory infections, and recent clinical data suggest that it may prevent secondary infection complications as well. We investigated the role of standardized E. purpurea (Echinaforce(®) extract or EF) on H3N2-induced adhesion of live nontypeable Haemophilus influenzae (NTHi) and Staphylococcus aureus, along with the expression of bacterial receptors, intracellular adhesion molecule-1 (ICAM-1), fibronectin, and platelet activating factor receptor (PAFr), by BEAS-2B cells. Inflammatory processes were investigated by determining the cellular expression of IL-6 and IL-8 and the involvement of Toll-like receptor (TLR-4) and NFκB p65. We found that influenza virus A infection increased the adhesion of H. influenzae and S. aureus to bronchial epithelial cells via upregulated expression of the ICAM-1 receptor and, to some extent, of fibronectin and PAFr. Echinaforce (EF) significantly reduced the expression of ICAM-1, fibronectin, and PAFr and consequently the adhesion of both bacterial strains. EF also effectively prevented the super-expression of inflammatory cytokines by suppressing the expression of NFκB and possibly TLR-4. These results indicate that E. purpurea has the potential to reduce the

  2. Standoff laser-induced fluorescence of suspensions from different bacterial strains

    NASA Astrophysics Data System (ADS)

    Duschek, Frank; Walter, Arne; Fellner, Lea; Grünewald, Karin; Pargmann, Carsten; Handke, Jürgen; Tomaso, Herbert

    2016-10-01

    Biological hazardous substances like certain fungi and bacteria represent a high risk for the broad public if fallen into wrong hands. Incidents based on bio agents are commonly considered to have incalculable and complex consequences for first responders and people. The impact of such an event can be minimized by a combination of different sensor technologies that have been developed to detect bio-threats and to gather information after an incident. Sensors for bio-agents can be grouped into two categories. Sampling devices collect material from locations supposed to be contaminated, and they are able to identify biological material with high sensitivity and selectivity. However, these point sensors need to be positioned correctly in advance of an attack, and moving sources of biological material cannot be tracked. A different approach is based on optical standoff detection. For biological samples laser induced florescence (LIF) has been proven to get real time data on location and type of hazards without being in contact with the suspicious substance. This work is based on a bio-detector developed at the DLR Lampoldshausen. The LIF detection has been designed for outdoor operation at standoff distances from 20 m up to more than 100 m. The detector acquires LIF spectral data for two different excitation wavelengths (280 and 355 nm) as well as time resolved information for the fluorescence decay which can be used to classify suspicious samples. While the classification device had been trained on uncritical samples (like amino acids, NADH, yeast, chemicals, oils), this work presents the progress to more relevant, living bacteria of different strains. The low risk and non-pathogenic bacteria Bacillus thuringensis, Bacillus atrophaeus, Bacillus subtilis, Brevibacillus brevis, Micrococcus luteus, Oligella urethralis, Paenibacillus polymyxa and Escherichia coli (K12) have been investigated with the above set-up at both excitation wavelengths

  3. Antibacterial active compounds from Hypericum ascyron L. induce bacterial cell death through apoptosis pathway.

    PubMed

    Li, Xiu-Mei; Luo, Xue-Gang; Si, Chuan-Ling; Wang, Nan; Zhou, Hao; He, Jun-Fang; Zhang, Tong-Cun

    2015-01-01

    Hypericum ascyron L. has been used as a traditional medicine for the treatment of wounds, swelling, headache, nausea and abscesses in China for thousands of years. However, modern pharmacological studies are still necessary to provide a scientific basis to substantiate their traditional use. In this study, the mechanism underlying the antimicrobial effect of the antibacterial activity compounds from H. ascyron L. was investigated. Bioguided fractionation of the extract from H. ascyron L. afforded antibacterial activity fraction 8. The results of cup plate analysis and MTT assay showed that the MIC and MBC of fraction 8 is 5 mg/mL. Furthermore, using Annexin V-FITC/PI, TUNEL labeling and DNA gel electrophoresis, we found that cell death with apoptosis features similar to those in eucaryon could be induced in bacteria strains after exposure to the antibacterial activity compounds from H. ascyron L. at moderate concentration. In addition, we further found fraction 8 could disrupt the cell membrane potential indicate that fraction 8 exerts pro-apoptotic effects through a membrane-mediated apoptosis pathway. Finally, quercetin and kaempferol 3-O-β-(2″-acetyl)-galactopyranoside, were identified from fraction 8 by means of Mass spectrometry and Nuclear magnetic resonance. To our best knowledge, this study is the first to show that Kaempferol 3-O-β-(2″-acetyl)-galactopyranoside coupled with quercetin had significant antibacterial activity via apoptosis pathway, and it is also the first report that Kaempferol 3-O-β-(2″-acetyl)-galactopyranoside was found in clusiacea. Our data might provide a rational base for the use of H. ascyron L. in clinical, and throw light on the development of novel antibacterial drugs.

  4. Detection of bacterial infection of agave plants by laser-induced fluorescence.

    PubMed

    Cervantes-Martínez, Jesús; Flores-Hernández, Ricardo; Rodríguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  5. Detection of bacterial infection of agave plants by laser-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  6. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    PubMed Central

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 h post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen colonization. This study

  7. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    PubMed

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 h post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen colonization. This study

  8. Mechanisms affecting swelling in alloys with precipitates

    SciTech Connect

    Mansur, L.K.; Haynes, M.R.; Lee, E.H.

    1980-01-01

    In alloys under irradiation many mechanisms exist that couple phase instability to cavity swelling. These are compounded with the more familiar mechanisms associated with point defect behavior and the evolution of microstructure. The mechanisms may be classified according to three modes of operation. Some affect cavity swelling directly by cavity-precipitate particle association, others operate indirectly by precipitate-induced changes in sinks other than cavities and finally there are mechanisms that are mediated by precipitate-induced changes in the host matrix. The physics of one mechanism of each type is developed in detail and the results compared where possible to experimental measurements. In particular, we develop the theory necessary to treat the effects on swelling of precipitation-induced changes in overall sink density; precipitation-induced changes in point defect trapping by solute depletion and creation of precipitate particle-matrix interfacial trap sites.

  9. Typhoon-induced precipitation impact on nutrient and suspended matter dynamics of a tropical estuary affected by human activities in Hainan, China

    NASA Astrophysics Data System (ADS)

    Herbeck, Lucia S.; Unger, Daniela; Krumme, Uwe; Liu, Su Mei; Jennerjahn, Tim C.

    2011-07-01

    Typhoons regularly hit the coasts along the northern South China Sea during summer monsoon. However, little is known on the effects of typhoon-related heavy precipitation on estuarine dynamics and coastal ecosystems. We analyzed physico-chemical characteristics, and concentrations and composition of dissolved and suspended matter in the Wenchang/Wenjiao Estuary (WWE) on the tropical island of Hainan, China, prior to and after typhoon Kammuri in August 2008. Before the typhoon, the estuary displayed vertical and horizontal gradients. High nutrient inputs from agriculture and widespread aquaculture were to a large extent converted into biomass inside the estuarine lagoon resulting in low export of nutrients to coastal waters and a mainly autochthonous origin of total suspended matter (TSM). Heavy typhoon-associated precipitation increased river runoff, which moved the location of the estuarine salinity gradient seaward. It resulted in an export of dissolved and particulate matter to coastal waters one day after the typhoon. Dissolved nutrients increased by up to an order of magnitude and TSM increased approximately twofold compared to pre-typhoon values. Lower δ 13C org and δ 15N and elevated C/N ratios of TSM together with lower chlorophyll a (chl a) concentrations indicated an increased contribution of terrestrial material originating from typhoon-induced soil erosion. Local uptake of excess nutrients inside the lagoon was inhibited because of reduced water transparency and the lack of phytoplankton, which had been washed out by the initial freshwater pulse. Two weeks after the typhoon, TSM concentration and composition had almost returned to pre-typhoon conditions. However, physico-chemical properties and nutrients were still different from pre-typhoon conditions indicating that the estuarine system had not fully recovered. Unusually high chl a concentrations in the coastal zone indicated a phytoplankton bloom resulting from the typhoon-induced nutrient export

  10. Analyses of Patois group bunyaviruses: evidence for naturally occurring recombinant bunyaviruses and existence of immune precipitable and nonprecipitable nonvirion proteins induced in bunyavirus-infected cells.

    PubMed

    Ushijima, H; Clerx-Van Haaster, C M; Bishop, D H

    1981-04-30

    Shark River (SR) and Pahayokee (PAH) bunyaviruses (Patois serogroup, Bunyavirus genus, family Bunyaviridae) have almost identical L and S RNA oligonucleotide fingerprints, but M RNA fingerprints that are different, suggesting that the two viruses may represent naturally occurring reassortant viruses. These observations are in agreement with serological studies (B. N. Fields, B. E. Henderson, P. H. Coleman, and T. H. Work, 1969, Amer. J. Epidemiol., 89, 222-226) which have distinguished these two viruses by neutralization of infectivity tests (presumably reflecting differences in M RNA gene products, J. R. Gentsch, E. J. Rozhon, R. A. Klimas, L. H. El Said, R. E. Shope, and D. H. L. Bishop, 1980, Virology102, 190-204), but not by complement fixation tests (which probably relate to the viral N polypeptide coded by the S RNA, J. Gentsch, L. R. Wynne, J. P. Clewley, R. E. Shope, and D. H. L. Bishop, 1977b, J. Virol. 24,893-902). The 3' terminal 11 nucleotides of PAH S RNA (3' (HO)OUCAUCAAAUGA ... 5') are identical in sequence to those of the S RNA species of snowshoe hare (SSH) and La Crosse (LAC) viruses, except for a position 7A residue which is a C residue in the SSH and LAC sequences. The major virion polypeptides of SR and PAH viruses include a nucleocapsid polypeptide (N, 22 x 10(3)) and two glycoproteins (PAH: G1 118 x 10(3), G2, 35 x 10(3); SR: G1 113 x 10(3), G2, 35 x 10(3)). In SR-infected cells several immune precipitable polypeptides have been detected. These include 11-, 54-, 64-, 93-, and 104 x 10(3)-dalton polypeptides. In addition, both SR and PAH viruses induce a 74 x 10(3)-dalton polypeptide (p74) that has not been detected in actinomycin D-treated infected cells, and is not immune precipitated from infected cell extracts.

  11. Microbial composition in a deep saline aquifer in the North German Basin -microbiologically induced corrosion and mineral precipitation affecting geothermal plant operation and the effects of plant downtime

    NASA Astrophysics Data System (ADS)

    Lerm, Stephanie; Westphal, Anke; Miethling-Graff, Rona; Alawi, Mashal; Seibt, Andrea; Wolfgramm, Markus; Würdemann, Hilke

    2013-04-01

    The microbial composition in fluids of a deep saline geothermal used aquifer in the North German Basin was characterized over a period of five years. The genetic fingerprinting techniques PCR-SSCP and PCR-DGGE revealed distinct microbial communities in fluids produced from the cold and warm side of the aquifer. Direct cell counting and quantification of 16S rRNA genes and dissimilatory sulfite reductase (dsrA) genes by real-time PCR proved different population sizes in fluids, showing higher abundance of Bacteria and sulfate reducing bacteria (SRB) in cold fluids compared to warm fluids. Predominating SRB in the cold well probably accounted for corrosion damage to the submersible well pump, and iron sulfide precipitates in the near wellbore area and topside facility filters. This corresponded to a lower sulfate content in fluids produced from the cold well as well as higher content of hydrogen gas that was probably released from corrosion, and maybe favoured growth of hydrogenotrophic SRB. Plant downtime significantly influenced the microbial biocenosis in fluids. Samples taken after plant restart gave indications about the processes occurring downhole during those phases. High DNA concentrations in fluids at the beginning of the restart process with a decreasing trend over time indicated a higher abundance of microbes during plant downtime compared to regular plant operation. It is likely that a gradual drop in temperature as well as stagnant conditions favoured the growth of microbes and maturation of biofilms at the casing and in pores of the reservoir rock in the near wellbore area. Furthermore, it became obvious that the microorganisms were more associated to particles then free-living. This study reflects the high influence of microbial populations for geothermal plant operation, because microbiologically induced precipitative and corrosive processes adversely affect plant reliability. Those processes may favourably occur during plant downtime due to enhanced

  12. Role of hydroperoxide lyase in white-backed planthopper (Sogatella furcifera Horváth)-induced resistance to bacterial blight in rice, Oryza sativa L.

    PubMed

    Gomi, Kenji; Satoh, Masaru; Ozawa, Rika; Shinonaga, Yumi; Sanada, Sachiyo; Sasaki, Katsutomo; Matsumura, Masaya; Ohashi, Yuko; Kanno, Hiroo; Akimitsu, Kazuya; Takabayashi, Junji

    2010-01-01

    A pre-infestation of the white-backed planthopper (WBPH), Sogatella furcifera Horváth, conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice (Oryza sativa L.) under both laboratory and field conditions. The infestation of another planthopper species, the brown planthopper (BPH) Nilaparvata lugens Stål, did not significantly reduce the incidence of bacterial blight symptoms. A large-scale screening using a rice DNA microarray and quantitative RT-PCR revealed that WBPH infestation caused the upregulation of more defence-related genes than did BPH infestation. Hydroperoxide lyase 2 (OsHPL2), an enzyme for producing C(6) volatiles, was upregulated by WBPH infestation, but not by BPH infestation. One C(6) volatile, (E)-2-hexenal, accumulated in rice after WBPH infestation, but not after BPH infestation. A direct application of (E)-2-hexenal to a liquid culture of Xoo inhibited the growth of the bacterium. Furthermore, a vapour treatment of rice plants with (E)-2-hexenal induced resistance to bacterial blight. OsHPL2-overexpressing transgenic rice plants exhibited increased resistance to bacterial blight. Based on these data, we conclude that OsHPL2 and its derived (E)-2-hexenal play some role in WBPH-induced resistance in rice.

  13. Induced drought tolerance through wild and mutant bacterial strain Pseudomonas simiae in mung bean (Vigna radiata L.).

    PubMed

    Kumari, Sarita; Vaishnav, Anukool; Jain, Shekhar; Varma, Ajit; Choudhary, Devendra Kumar

    2016-01-01

    The present study focused on the overproducing mutant of a plant growth promoting rhizobacterium (PGPR) Pseudomonas simiae strain AU (MTCC-12057) for significant drought tolerance in mung bean plants. Five mutants namely AU-M1, AU-M2, AU-M3, AU-M4 and AU-M5 were made after treatment of wild type strain with N-methyl-N-nitro-N-nitrosoguanidine. Mutant strain AU-M4 was recorded for enhanced ACC deaminase (ACC-D) activity, indole acetic acid (IAA) production and inorganic phosphate (Pi) solubilization compared to wild strain and other four mutant strains under drought condition. AU-M4 showed higher phosphate solubilization index (8.17) together with higher ACC-D activity (98 nmol/mg/h) and IAA concentration (69.35 µg/ml) compared with the wild type P. simiae strain AU ACC-D activity (79 nmol/mg/h) and IAA concentration (38.98 µg/ml) respectively. In this report, we investigated the effect of both wild and mutant type bacterial strain on mung bean plants under drought stress. Results showed that mutant AU-M4 and wild type strain AU inoculated plants exhibited superior tolerance against drought stress, as shown by their enhanced plant biomass (fresh weight), higher water content, higher proline accumulation and lower osmotic stress injury. Mutant AU-M4 and wild strain AU inoculated plants reduced the ethylene level by 59 and 45% respectively, compared to the control under stress condition. Furthermore, bacterial inoculated plants showed enhanced induced systemic drought tolerance by reducing stomata size and net photosynthesis resulting higher water content in mung bean plants that may help in survival of plants during drought condition. To mitigate the effects of drought stress, use of PGPR will be needed to ensure sufficient production of food from crop plants. Taking current leads available, concerted future research is needed in this area, particularly on field evaluation with application of potential microorganisms.

  14. Microbial Precipitation and Diagenesis in Salt Ponds from Little Darby Island, Exumas, Bahamas.

    NASA Astrophysics Data System (ADS)

    Piggot, A. M.; Klaus, J.; Swart, P. K.; Reid, P.

    2014-12-01

    Microbial activity is responsible for the majority of carbonate precipitation and early diagenesis in restricted hypersaline ponds on Little Darby Island, Bahamas. The four ponds on Little Darby exhibit a range of salinities (10-69) and sedimentary deposits that record the evolution of ponds from restricted shallow marine embayments to isolated hypersaline ponds. Only the largest and most hypersaline pond, Anaconda, was covered by a classically defined multi-layered microbial mat (3 cm thick) with calcium carbonate precipitates. Microbial laminations and organosedimentary layers were preserved throughout the 90cm sediment core. The brackish ponds had thinner (< 0.5cm) microbial mats and appeared to be non-carbonate precipitating, with no preserved laminated mats in the subsurface. Despite differences in observed precipitation, molecular and geochemical evidence for microbially induced carbonate precipitation and diageneiss was observed in all four ponds. High-throughput 454 pyrosequencing and phylogenetic analysis of 16S rRNA genes identified the same dominant bacterial groups in all four ponds, such as Actinobacteria, Alphaproteobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Deltaproteobacteria, Gammaproteobacteria and Planctomycetes, with metabolisms previously linked to carbonate producing mat systems. Sulfate reduction and heterotrophic degradation of exopolymeric substances were identified as the primary mechanism for microbial carbonate precipitation. The δ13C values of carbonate sediments ranged from -5.5‰ to 3‰, with the more negative values representing the heterotrophic involvement in carbonate precipitation. The more positive values (0-3‰) were associated with the deeper sediments deposited in a marine environment before the ponds were isolated. Pore fluid chemical ratios of Ca2+/Cl-, Mg2+/Cl-, and Sr2+/Cl- ratios also suggest that precipitation and recrystallization of carbonate minerals is occurring in the buried sediments and indicates

  15. Prospecting for new bacterial metabolites: a glossary of approaches for inducing, activating and upregulating the biosynthesis of bacterial cryptic or silent natural products.

    PubMed

    Zarins-Tutt, Joseph Scott; Barberi, Tania Triscari; Gao, Hong; Mearns-Spragg, Andrew; Zhang, Lixin; Newman, David J; Goss, Rebecca Jane Miriam

    2016-01-01

    Covering: up to 2015. Over the centuries, microbial secondary metabolites have played a central role in the treatment of human diseases and have revolutionised the pharmaceutical industry. With the increasing number of sequenced microbial genomes revealing a plethora of novel biosynthetic genes, natural product drug discovery is entering an exciting second golden age. Here, we provide a concise overview as an introductory guide to the main methods employed to unlock or up-regulate these so called 'cryptic', 'silent' and 'orphan' gene clusters, and increase the production of the encoded natural product. With a predominant focus on bacterial natural products we will discuss the importance of the bioinformatics approach for genome mining, the use of first different and simple culturing techniques and then the application of genetic engineering to unlock the microbial treasure trove.

  16. Numerical simulation of precipitation formation in the case orographically induced convective cloud: Comparison of the results of bin and bulk microphysical schemes

    NASA Astrophysics Data System (ADS)

    Sarkadi, N.; Geresdi, I.; Thompson, G.

    2016-11-01

    In this study, results of bulk and bin microphysical schemes are compared in the case of idealized simulations of pre-frontal orographic clouds with enhanced embedded convection. The description graupel formation by intensive riming of snowflakes was improved compared to prior versions of each scheme. Two methods of graupel melting coincident with collisions with water drops were considered: (1) all simulated melting and collected water drops increase the amount of melted water on the surface of graupel particles with no shedding permitted; (2) also no shedding permitted due to melting, but the collision with the water drops can induce shedding from the surface of the graupel particles. The results of the numerical experiments show: (i) The bin schemes generate graupel particles more efficiently by riming than the bulk scheme does; the intense riming of snowflakes was the most dominant process for the graupel formation. (ii) The collision-induced shedding significantly affects the evolution of the size distribution of graupel particles and water drops below the melting level. (iii) The three microphysical schemes gave similar values for the domain integrated surface precipitation, but the patterns reveal meaningful differences. (iv) Sensitivity tests using the bulk scheme show that the depth of the melting layer is sensitive to the description of the terminal velocity of the melting snow. (v) Comparisons against Convair-580 flight measurements suggest that the bin schemes simulate well the evolution of the pristine ice particles and liquid drops, while some inaccuracy can occur in the description of snowflakes riming. (vi) The bin scheme with collision-induced shedding reproduced well the quantitative characteristics of the observed bright band.

  17. Protease activated receptor 4 limits bacterial growth and lung pathology during late stage Streptococcus pneumoniae induced pneumonia in mice.

    PubMed

    de Stoppelaar, S F; Van't Veer, C; van den Boogaard, F E; Nieuwland, R; Hoogendijk, A J; de Boer, O J; Roelofs, J J T H; van der Poll, T

    2013-09-01

    Streptococcus pneumoniae is a common causative pathogen of pneumonia and sepsis. Pneumonia and sepsis are associated with enhanced activation of coagulation, resulting in the production of several host-derived proteases at the primary site of infection and in the circulation. Serine proteases cleave protease activated receptors (PARs), which form a molecular link between coagulation and inflammation. PAR4 is one of four subtypes of PARs and is widely expressed by multiple cell types in the respiratory tract implicated in pulmonary inflammation, by immune cells and by platelets. In mice, mouse (m)PAR4 is the only thrombin receptor expressed by platelets. We here sought to determine the contribution of mPAR4 to the host response during pneumococcal pneumonia. Pneumonia was induced by intranasal inoculation with S. pneumoniae in mPAR4-deficient (par4-/-) and wild-type mice. Mice were sacrificed after 6, 24 or 48 hours (h). Blood, lungs, liver and spleen were collected for analyses. Ex vivo stimulation assays were performed with S. pneumoniae and mPAR4 activating peptides. At 48 h after infection, higher bacterial loads were found in the lungs and blood of par4-/- mice (p < 0.05), accompanied by higher histopathology scores and increased cytokine levels (p < 0.05) in the lungs. Ex vivo, co-stimulation with mPAR4 activating peptide enhanced the whole blood cytokine response to S. pneumoniae. Thrombin inhibition resulted in decreased cytokine release after S. pneumoniae stimulation in human whole blood. Our findings suggest that mPAR4 contributes to antibacterial defence during murine pneumococcal pneumonia.

  18. A bacterial metabolite induces glutathione-tractable proteostatic damage, proteasomal disturbances, and PINK1-dependent autophagy in C. elegans.

    PubMed

    Martinez, B A; Kim, H; Ray, A; Caldwell, G A; Caldwell, K A

    2015-10-15

    Gene-by-environment interactions are thought to underlie the majority of idiopathic cases of neurodegenerative disease. Recently, we reported that an environmental metabolite extracted from Streptomyces venezuelae increases ROS and damages mitochondria, leading to eventual neurodegeneration of C. elegans dopaminergic neurons. Here we link those data to idiopathic disease models that predict loss of protein handling as a component of disorder progression. We demonstrate that the bacterial metabolite leads to proteostatic disruption in multiple protein-misfolding models and has the potential to synergistically enhance the toxicity of aggregate-prone proteins. Genetically, this metabolite is epistatically regulated by loss-of-function to pink-1, the C. elegans PARK6 homolog responsible for mitochondrial maintenance and autophagy in other animal systems. In addition, the metabolite works through a genetic pathway analogous to loss-of-function in the ubiquitin proteasome system (UPS), which we find is also epistatically regulated by loss of PINK-1 homeostasis. To determine remitting counter agents, we investigated several established antioxidants and found that glutathione (GSH) can significantly protect against metabolite-induced proteostasis disruption. In addition, GSH protects against the toxicity of MG132 and can compensate for the combined loss of both pink-1 and the E3 ligase pdr-1, a Parkin homolog. In assessing the impact of this metabolite on mitochondrial maintenance, we observe that it causes fragmentation of mitochondria that is attenuated by GSH and an initial surge in PINK-1-dependent autophagy. These studies mechanistically advance our understanding of a putative environmental contributor to neurodegeneration and factors influencing in vivo neurotoxicity.

  19. Intranasal immunization with a mixture of PspA and a Toll-like receptor agonist induces specific antibodies and enhances bacterial clearance in the airways of mice.

    PubMed

    Oma, Keita; Zhao, Jizi; Ezoe, Hirokazu; Akeda, Yukihiro; Koyama, Shohei; Ishii, Ken J; Kataoka, Kosuke; Oishi, Kazunori

    2009-05-21

    To develop an effective nasal vaccine for Streptococcus pneumoniae, the effects of a panel of Toll-like receptor (TLR) agonists in combination with pneumococcal surface protein A (PspA) on induction of PspA-specific antibodies and bacterial clearance were compared in mice. Mice were nasally immunized with 10 microg of TLR agonist (TLR 2-4 and 9) and 2.5 microg of PspA once per week for 3 weeks. Significantly increased levels of PspA-specific immunoglobulin G (IgG) and IgA in the airways and PspA-specific IgG in plasma were found in mice administered PspA plus each TLR agonist, compared with mice administered PspA alone. In a sub-lethal pneumonia model using a serotype 3 pneumococcal strain, bacterial density in the lungs of mice was significantly reduced in mice administered PspA plus each TLR agonist, compared with mice administered either PspA alone or phosphate-buffered saline alone 3h after bacterial challenge. Similarly, enhanced bacterial clearance was found in the nasopharynx of mice administered PspA plus each TLR agonist 1 day after infection with a serotype 19F strain. Our data suggest that PspA-specific antibody induced by nasal immunization with PspA plus TLR agonist is capable of reducing the bacterial load in both the nasopharynx and lungs after challenge with pneumococci with different serotypes. Despite the skewed Th1/Th2 immune responses, the effects of nasal immunization with PspA plus each TLR agonist on bacterial clearances from the lungs 3h after infection and from nasopharynx 1 day after infection in mice were equivalent.

  20. Transcriptome Analysis Reveals Comprehensive Insights into the Early Immune Response of Large Yellow Croaker (Larimichthys crocea) Induced by Trivalent Bacterial Vaccine

    PubMed Central

    Mu, Pengfei; Ao, Jingqun; Chen, Xinhua

    2017-01-01

    Vaccination is an effective and safe strategy for combating bacterial diseases in fish, but the mechanisms underlying the early immune response after vaccination remain to be elucidated. In the present study, we used RNA-seq technology to perform transcriptome analysis of spleens from large yellow croaker (Larimichthys crocea) induced by inactivated trivalent bacterial vaccine (Vibrio parahaemolyticus, Vibrio alginolyticus and Aeromonas hydrophila). A total of 2,789 or 1,511 differentially expressed genes (DEGs) were obtained at 24 or 72 h after vaccination, including 1,132 or 842 remarkably up-regulated genes and 1,657 or 669 remarkably down-regulated genes, respectively. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichments revealed that numerous DEGs belong to immune-relevant genes, involved in many immune-relevant pathways. Most of the strongly up-regulated DEGs are innate defense molecules, such as antimicrobial peptides, complement components, lectins, and transferrins. Trivalent bacterial vaccine affected the expressions of many components associated with bacterial ligand–depending Toll-like receptor signaling pathways and inflammasome formation, indicating that multiple innate immune processes were activated at the early period of vaccination in large yellow croaker. Moreover, the expression levels of genes involved in antigen processing were also up-regulated by bacterial vaccine. However, the expression levels of several T cell receptors and related CD molecules and signal transducers were down-regulated, suggesting that the T cell receptor signaling pathway was rapidly suppressed after vaccination. These results provide the comprehensive insights into the early immune response of large yellow croaker to vaccination and valuable information for developing a highly immunogenic vaccine against bacterial infection in teleosts. PMID:28135311

  1. Multi-satellite sensor study on precipitation-induced emission pulses of NOx from soils in semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    Zörner, Jan; Penning de Vries, Marloes; Beirle, Steffen; Veres, Patrick; Williams, Jonathan; Wagner, Thomas

    2016-04-01

    Soil emissions of NOx (≡ NO + NO2), stemming from biotic emissions of NO, represent a considerable fraction of total NOx emissions, and may even dominate in agricultural and remote areas. Rain-induced spikes in NOx have been observed by in-situ measurements and also satellite observations. However, the estimation of soil emissions over broad geographic regions and on short time scales remains uncertain. This study presents a top-down approach to estimate pulsed soil emissions of trace gases on a global scale using tropospheric NO2 column densities (as a proxy for NOx) as observed by OMI, GOME-2 and SCIAMACHY. We introduce an optimized algorithm that synchronizes and averages multiple time series of atmospheric variables either from one location only, or also from different grid pixels, by aligning them on a relative scale to each other. This method allows investigating changes in the evolution of NO2 VCDs around the first day of rainfall after a prolonged dry period with a temporal resolution of one day and a spatial resolution of 0.25° . We find enhancements in NO2 VCDs on the day of first rainfall in many semi-arid regions in the world which are highly dependent on the season and land cover type. Strongest and most clustered enhancements are found in the distinct band of the Sahel region during the onset of the wet season in April-May-June. Absolute enhancements averaged over the Sahel region for four seasons from 2007 to 2010 range from 0.3*1015molec cm-2 for OMI to 0.4*1015molec cm-2 for GOME-2 and SCIAMACHY on the first day of rainfall. A thorough analysis of other influences on the retrieved signal as well as sensitivity studies are conducted which help to better characterize these short term enhancements. Translating the observed enhancements in NO2 VCDs to emission rates, leads to estimates between 5 and 65 ng N m-2 s-1 for the first day of rainfall which is in line with previous literature. We find that the enhancement in NO2 VCDs already starts to

  2. Anti-bacterial and anti-toxic immunity induced by a killed whole-cell-cholera toxin B subunit cholera vaccine is essential for protection against lethal bacterial infection in mouse pulmonary cholera model.

    PubMed

    Kang, S-S; Yang, J S; Kim, K W; Yun, C-H; Holmgren, J; Czerkinsky, C; Han, S H

    2013-07-01

    The lack of appropriate animal model for studying protective immunity has limited vaccine development against cholera. Here, we demonstrate a pulmonary cholera model conferred by intranasal administration of mice with live Vibrio cholerae. The bacterial components, but not cholera toxin, caused lethal and acute pneumonia by inducing massive inflammation. Intranasal immunization with Dukoral, comprising killed whole bacteria and recombinant cholera toxin B subunit (rCTB), developed both mucosal and systemic antibody responses with protection against the lethal challenge. Either rCTB-free Dukoral or rCTB alone partially protected the mice against the challenge. However, reconstitution of rCTB-free Dukoral with rCTB restored full protection. Parenteral immunization with Dukoral evoked strong systemic immunity without induction of mucosal immunity or protection from the challenge. These results suggest that both anti-bacterial and anti-toxic immunity are required for protection against V. cholerae-induced pneumonia, and this animal model is useful for pre-clinical evaluation of candidate cholera vaccines.

  3. Lidar and radar measurements of the melting layer in the frame of the Convective and Orographically-induced Precipitation Study: observations of dark and bright band phenomena

    NASA Astrophysics Data System (ADS)

    di Girolamo, P.; Summa, D.; Bhawar, R.; di Iorio, T.; Norton, E. G.; Peters, G.; Dufournet, Y.

    2011-11-01

    During the Convective and Orographically-induced Precipitation Study (COPS), lidar dark and bright bands were observed by the University of BASILicata Raman lidar system (BASIL) during several intensive (IOPs) and special (SOPs) observation periods (among others, 23 July, 15 August, and 17 August 2007). Lidar data were supported by measurements from the University of Hamburg cloud radar MIRA 36 (36 GHz), the University of Hamburg dual-polarization micro rain radars (24.1 GHz) and the University of Manchester UHF wind profiler (1.29 GHz). Results from BASIL and the radars for 23 July 2007 are illustrated and discussed to support the comprehension of the microphysical and scattering processes responsible for the appearance of the lidar and radar dark and bright bands. Simulations of the lidar dark and bright band based on the application of concentric/eccentric sphere Lorentz-Mie codes and a melting layer model are also provided. Lidar and radar measurements and model results are also compared with measurements from a disdrometer on ground and a two-dimensional cloud (2DC) probe on-board the ATR42 SAFIRE.

  4. Characterization of convection-related parameters by Raman lidar: Analysis of selected case studies from the Convective and Orographically-induced Precipitation Study

    NASA Astrophysics Data System (ADS)

    Di Girolamo, P.; Summa, D.; Stelitano, D.

    2012-04-01

    This paper illustrates an approach to determine the convective available potential energy (CAPE) and the convective inhibition (CIN) based on the use of data from a Raman lidar system. The use of Raman lidar data allows to provide high temporal resolution (5 min) measurements of CAPE and CIN and follow their evolution over extended time period covering the full cycle of convective activity. Lidar-based measurements of CAPE and CIN are obtained from Raman lidar measurements of the temperature profile and the surface measurements of temperature, pressure and dew point temperature provided from a surface weather station. The approach is tested and applied to the data collected by the Raman lidar system BASIL, which was operational in Achern (Black Forest, Lat: 48.64 ° N, Long: 8.06 ° E, Elev.: 140 m) in the period 01 June - 31 August 2007 in the frame of the Convective and Orographically-induced Precipitation Study (COPS), held in Southern Germany and Eastern France. Reported measurements are found to be in good agreement with simultaneous measurements obtained from the radiosondes launched in Achern and with estimates from different mesoscale models. An estimate of the different random error sources affecting the measurements of CAPE and CIN has also been performed, together with a detail sensitivity study to quantify the different systematic error sources. Preliminary results from this study will be illustrated and discussed at the Conference.

  5. On the mechanism of apatite-induced precipitation on 45S5 glass pellets coated with a natural-derived polymer

    NASA Astrophysics Data System (ADS)

    Araújo, Marco; Miola, Marta; Bertone, Elisa; Baldi, Giovanni; Perez, Javier; Verné, Enrica

    2015-10-01

    In this work, the bioactive glass 45S5 (also known by its commercial name Bioglass®) was successfully dip-coated by a natural derived biopolymer, increasing its apatite-forming ability. The biopolymer was shown to accelerate the first stages of bioactivity, inducing a fast transition to step 4 (formation of amorphous Casbnd P layer) in the apatite-forming ability mechanism. The faster precipitation of Ca/P crystals in the coated samples resulted in the formation of an intermediate amorphous octacalcium phosphate, which later transforms into an apatite layer with high thickness. The effect of the thickness of the coating was also studied on samples coated with polymer suspensions of different concentrations (0.15% and 1.5%, w/v), revealing that the kinetics of formation of the final hydroxycarbonate apatite layer increases with the thickness of the coating. The mechanism by which this apatite-forming ability is accelerated was also investigated, revealing that certain functional groups present in the structure of the polymer allow it to act as an organic matrix and preferential nucleation site for the growth of the hydroxycarbonate apatite layer.

  6. Changes in the structural composition and reactivity of Acer rubrum leaf litter tannins exposed to warming and altered precipitation: climatic stress-induced tannins are more reactive.

    PubMed

    Tharayil, Nishanth; Suseela, Vidya; Triebwasser, Daniella J; Preston, Caroline M; Gerard, Patrick D; Dukes, Jeffrey S

    2011-07-01

    • Climate change could increase the frequency with which plants experience abiotic stresses, leading to changes in their metabolic pathways. These stresses may induce the production of compounds that are structurally and biologically different from constitutive compounds. • We studied how warming and altered precipitation affected the composition, structure, and biological reactivity of leaf litter tannins in Acer rubrum at the Boston-Area Climate Experiment, in Massachusetts, USA. • Warmer and drier climatic conditions led to higher concentrations of protective compounds, including flavonoids and cutin. The abundance and structure of leaf tannins also responded consistently to climatic treatments. Drought and warming in combination doubled the concentration of total tannins, which reached 30% of leaf-litter DW. This treatment also produced condensed tannins with lower polymerization and a greater proportion of procyanidin units, which in turn reduced sequestration of tannins by litter fiber. Furthermore, because of the structural flexibility of these tannins, litter from this treatment exhibited five times more enzyme (β-glucosidase) complexation capacity on a per-weight basis. Warmer and wetter conditions decreased the amount of foliar condensed tannins. • Our finding that warming and drought result in the production of highly reactive tannins is novel, and highly relevant to climate change research as these tannins, by immobilizing microbial enzymes, could slow litter decomposition and thus carbon and nutrient cycling in a warmer, drier world.

  7. Dose dependent inhibitory effect of dietary caraway on 1,2-dimethylhydrazine induced colonic aberrant crypt foci and bacterial enzyme activity in rats.

    PubMed

    Deeptha, Kumaraswami; Kamaleeswari, Muthaiyan; Sengottuvelan, Murugan; Nalini, Namasivayam

    2006-11-01

    Colon cancer has become one of the major causes of cancer mortality. We determined the effect of caraway (Carum carvi L.) on the development of aberrant crypt foci (ACF) and modulation of fecal bacterial enzyme activities in 1,2-dimethylhydrazine (DMH)-induced experimental rat colon carcinogenesis. Male Wistar albino rats were divided into six groups and all the animals were fed 15.8% peanut oil making a total of 20% fat in the diet. Group 1 served as control and group 2 animals received 90 mg/kg body weight caraway p.o. daily for 15 weeks. To induce ACF, DMH (20 mg/kg body weight) was injected subcutaneously once a week for the first four weeks (groups 3-6). In addition caraway was administered at the dose of 30, 60 and 90 mg/kg body weight everyday orally for the entire period of 15 weeks (groups 4-6). First, we analyzed ACF number (incidence), multiplicity and its distribution along the colon in all experimental groups at the end of 15 weeks. Subsequently, we also assayed the fecal bacterial enzyme activities. ACF formation and the fecal bacterial enzyme activities were found to be significantly high in DMH-alone treated group as compared to control group. Caraway supplementation at three different doses significantly suppressed ACF development, bacterial enzyme activities and modulated oxidative stress significantly as compared to the unsupplemented DMH-treated group. Results of our present study indicate that dietary caraway markedly inhibited DMH-induced colon carcinogenesis and the optimal dose of 60 mg/kg body weight was more effective than the other two doses.

  8. Strontium Co-precipitation During Biomineralization of Calcite in Porous Media Using Differing Treatment Strategies

    NASA Astrophysics Data System (ADS)

    Lauchnor, E. G.; Schultz, L.; Mitchell, A.; Cunningham, A. B.; Gerlach, R.

    2013-12-01

    the ureolytic biofilms and also insured that bacterially-induced mineralization was still occurring after 60 days of operation. Batch rate experiments demonstrated the effective use of alternative sources of substrates for biomineralization, which are economical for use in field-scale remediation. Fertilizer has been shown to be an effective urea source and several economical carbon and nutrient sources such as molasses and whey are being evaluated for stimulating ureolytic microorganisms. This research demonstrates on a bench scale the use of different injection strategies to control precipitation of calcium carbonate, as well as the feasibility of strontium co-precipitation in porous media. The ongoing optimization of strontium co-precipitation will lead to additional work on potential remediation of other heavy metal groundwater contaminants.

  9. Optimum conditions for microbial carbonate precipitation.

    PubMed

    Okwadha, George D O; Li, Jin

    2010-11-01

    The type of bacteria, bacterial cell concentration, initial urea concentration, reaction temperature, the initial Ca(2+) concentration, ionic strength, and the pH of the media are some factors that control the activity of the urease enzyme, and may have a significant impact on microbial carbonate precipitation (MCP). Factorial experiments were designed based on these factors to determine the optimum conditions that take into consideration economic advantage while at the same time giving quality results. Sporosarcina pasteurii strain ATCC 11859 was used at constant temperature (25°C) and ionic strength with varying amounts of urea, Ca(2+), and bacterial cell concentration. The results indicate that the rate of ureolysis (k(urea)) increases with bacterial cell concentration, and the bacterial cell concentration had a greater influence on k(urea) than initial urea concentration. At 25 mM Ca(2+) concentration, increasing bacterial cell concentration from 10(6) to 10(8)cells mL⁻¹ increased the CaCO(3) precipitated and CO(2) sequestrated by over 30%. However, when the Ca(2+) concentration was increased 10-fold to 250 mM Ca(2+), the amount of CaCO(3) precipitated and CO(2) sequestrated increased by over 100% irrespective of initial urea concentration. Consequently, the optimum conditions for MCP under our experimental conditions were 666 mM urea and 250 mM Ca(2+) at 2.3×10⁸ cells mL⁻¹ bacterial cell concentration. However, a greater CaCO(3) deposition is achievable with higher concentrations of urea, Ca(2+), and bacterial cells so long as the respective quantities are within their economic advantage. X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray analyzes confirmed that the precipitate formed was CaCO(3) and composed of predominantly calcite crystals with little vaterite crystals.

  10. Multidirectional chemical signalling between Mammalian hosts, resident microbiota, and invasive pathogens: neuroendocrine hormone-induced changes in bacterial gene expression.

    PubMed

    Karavolos, Michail H; Khan, C M Anjam

    2014-01-01

    Host-pathogen communication appears to be crucial in establishing the outcome of bacterial infections. There is increasing evidence to suggest that this communication can take place by bacterial pathogens sensing and subsequently responding to host neuroendocrine (NE) stress hormones. Bacterial pathogens have developed mechanisms allowing them to eavesdrop on these communication pathways within their hosts. These pathogens can use intercepted communication signals to adjust their fitness to persist and cause disease in their hosts. Recently, there have been numerous studies highlighting the ability of NE hormones to act as an environmental cue for pathogens, helping to steer their responses during host infection. Host NE hormone sensing can take place indirectly or directly via bacterial adrenergic receptors (BARs). The resulting changes in bacterial gene expression can be of strategic benefit to the pathogen. Furthermore, it is intriguing that not only can bacteria sense NE stress hormones but they are also able to produce key signalling molecules known as autoinducers. The rapid advances in our knowledge of the human microbiome, and its impact on health and disease highlights the potential importance of communication between the microbiota, pathogens and the host. It is indeed likely that the microbiota input significantly in the neuroendocrinological homeostasis of the host by catabolic, anabolic, and signalling processes. The arrival of unwanted guests, such as bacterial pathogens, clearly has a major impact on these delicately balanced interactions. Unravelling the pathways involved in interkingdom communication between invading bacterial pathogens, the resident microbiota, and hosts, may provide novel targets in our continuous search for new antimicrobials to control disease.

  11. ISR meets SAR outside: additive action of the endophyte Bacillus pumilus INR7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper.

    PubMed

    Yi, Hwe-Su; Yang, Jung Wook; Ryu, Choong-Min

    2013-01-01

    Induced resistance has been recognized as an attractive tool for plant disease management in modern agriculture. During the last two decades, studies on chemically- and biologically elicited induced resistance have revealed previously unknown features of the plant defense response including defense priming. As a biological trigger for induced resistance, plant growth-promoting rhizobacteria (PGPR) are a group of root-associated bacteria that can reduce plant disease severity and incidence, and augment plant growth and yield under greenhouse and field conditions. We evaluated the potential of an endophytic PGPR, Bacillus pumilus INR7, to induce systemic resistance against bacterial spot caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Trials in the greenhouse showed significantly less symptom development in pepper plants inoculated with strain INR7 compared to a water treatment. Furthermore, a single dipping treatment with INR7 before transplantation of pepper plants into the field elicited an induced systemic resistance response against bacterial spot caused by artificially infiltration of X. axonopodis pv. vesicatoria and even against naturally occurring bacterial spot disease. We identified an additive effect on induced resistance after administration of a combination treatment composed of strain INR7 with a chemical inducer, benzothiadiazole (BTH) in the field. The combination treatment stimulated expression of pepper defense marker genes CaPR1, CaTin1, and CaPR4 to a greater extent than did treatment with either agent alone. Similar experiments conducted with tobacco revealed no additive effects under field conditions. Interestingly, co-application of plants with INR7 lifted the growth repressing effect of BTH. Application of BTH onto pepper and tobacco did not affect rhizosphere colonization but supported a higher population density inside plant roots when compared to water-treated control plants. Our results indicate that PGPR can be used in

  12. ISR meets SAR outside: additive action of the endophyte Bacillus pumilus INR7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper

    PubMed Central

    Yi, Hwe-Su; Yang, Jung Wook; Ryu, Choong-Min

    2013-01-01

    Induced resistance has been recognized as an attractive tool for plant disease management in modern agriculture. During the last two decades, studies on chemically- and biologically elicited induced resistance have revealed previously unknown features of the plant defense response including defense priming. As a biological trigger for induced resistance, plant growth-promoting rhizobacteria (PGPR) are a group of root-associated bacteria that can reduce plant disease severity and incidence, and augment plant growth and yield under greenhouse and field conditions. We evaluated the potential of an endophytic PGPR, Bacillus pumilus INR7, to induce systemic resistance against bacterial spot caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Trials in the greenhouse showed significantly less symptom development in pepper plants inoculated with strain INR7 compared to a water treatment. Furthermore, a single dipping treatment with INR7 before transplantation of pepper plants into the field elicited an induced systemic resistance response against bacterial spot caused by artificially infiltration of X. axonopodis pv. vesicatoria and even against naturally occurring bacterial spot disease. We identified an additive effect on induced resistance after administration of a combination treatment composed of strain INR7 with a chemical inducer, benzothiadiazole (BTH) in the field. The combination treatment stimulated expression of pepper defense marker genes CaPR1, CaTin1, and CaPR4 to a greater extent than did treatment with either agent alone. Similar experiments conducted with tobacco revealed no additive effects under field conditions. Interestingly, co-application of plants with INR7 lifted the growth repressing effect of BTH. Application of BTH onto pepper and tobacco did not affect rhizosphere colonization but supported a higher population density inside plant roots when compared to water-treated control plants. Our results indicate that PGPR can be used in

  13. Formate Oxidation-Driven Calcium Carbonate Precipitation by Methylocystis parvus OBBP

    PubMed Central

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert

    2014-01-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such as ammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2−1 calcium carbonate precipitate yield was obtained when a culture of 109 cells ml−1 and 5 g of calcium formate liter−1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry. PMID:24837386

  14. Formate oxidation-driven calcium carbonate precipitation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert; Boon, Nico

    2014-08-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such asammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2(-1) calcium carbonate precipitate yield was obtained when a culture of 10(9) cells ml(-1) and 5 g of calcium formate liter(-)1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry.

  15. Bacterial contamination of blood components: Norwegian strategies in identifying donors with higher risk of inducing septic transfusion reactions in recipients.

    PubMed

    Klausen, Sofie Strand; Hervig, Tor; Seghatchian, Jerard; Reikvam, Håkon

    2014-10-01

    Bacterial contamination of blood and its cellular components remains the most common microbiological cause of transfusion associated morbidity and mortality, even in developed countries. This yet unresolved complication is seen more often in platelet transfusions, as platelet concentrates are stored at room temperature, in gas permeable containers with constant agitation, which support bacterial proliferation from relatively low undetectable levels, at the beginning of storage time, to relatively high virulent bacteria titers and endotoxin generation, at the end of shelf life. Accordingly, several combined strategies are introduced and implemented to at least reduce the potential risk of bacterial contaminated products for transfusion. These embody: improved donors arms cleaning; bacterial avoidance by diversion of the first portion of collection; reducing bacterial growth through development of newer storage media for longer platelet shelf life; bacterial load reduction by leucoreduction/viral inactivation, in some countries and eliminating the use potentially contaminated units through screening, through current available testing procedures, though none are not yet fully secure. We have not seen the same reduction in bacterial associated transfusion infections as we have observed for the sharp drop in transfusion associated transmission rates of HIV and hepatitis B and C. This great viral reduction is not only caused by the introduction of newer and more sensitive and specific detection methods for different viruses, but also the identification of donor risk groups through questionnaires and personal interviews. While search for more efficient methods for identifying potential blood donors with asymptomatic bacteremia, as well as a better way for detecting bacteria in stored blood components will be continuing, it is necessary to establish more standardized guidelines for the recognition the adverse reactions in recipients of potentially contaminated units

  16. Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.

    PubMed

    Daigneault, Marc; De Silva, Thushan I; Bewley, Martin A; Preston, Julie A; Marriott, Helen M; Mitchell, Andrea M; Mitchell, Timothy J; Read, Robert C; Whyte, Moira K B; Dockrell, David H

    2012-01-01

    Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease.

  17. Urban-development-induced Changes in the Diversity and Composition of the Soil Bacterial Community in Beijing

    NASA Astrophysics Data System (ADS)

    Yan, Bing; Li, Junsheng; Xiao, Nengwen; Qi, Yue; Fu, Gang; Liu, Gaohui; Qiao, Mengping

    2016-12-01

    Numerous studies have implicated urbanization as a major cause of loss of biodiversity. Most of them have focused on plants and animals, even though soil microorganisms make up a large proportion of that biodiversity. However, it is unclear how the soil bacterial community is affected by urban development. Here, paired-end Illumina sequencing of the 16 S rRNA gene at V4 region was performed to study the soil microbial community across Beijing’s built-up area. Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Gemmatimonadetes, Verrucomicrobia, Planctomycetes, and Chloroflexi were the dominant phyla in all samples, but the relative abundance of these phyla differed significantly across these concentric zones. The diversity and composition of the soil bacterial community were found to be closely correlated with soil pH. Variance partitioning analysis suggested that urban ring roads contributed 5.95% of the bacterial community variation, and soil environmental factors explained 17.65% of the variation. The results of the current work indicate that urban development can alter the composition and diversity of the soil microbial community, and showed pH to be a key factor in the shaping of the composition of the soil bacterial community. Urban development did have a strong impact on the bacterial community of urban soil in Beijing.

  18. Urban-development-induced Changes in the Diversity and Composition of the Soil Bacterial Community in Beijing

    PubMed Central

    Yan, Bing; Li, Junsheng; Xiao, Nengwen; Qi, Yue; Fu, Gang; Liu, Gaohui; Qiao, Mengping

    2016-01-01

    Numerous studies have implicated urbanization as a major cause of loss of biodiversity. Most of them have focused on plants and animals, even though soil microorganisms make up a large proportion of that biodiversity. However, it is unclear how the soil bacterial community is affected by urban development. Here, paired-end Illumina sequencing of the 16 S rRNA gene at V4 region was performed to study the soil microbial community across Beijing’s built-up area. Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Gemmatimonadetes, Verrucomicrobia, Planctomycetes, and Chloroflexi were the dominant phyla in all samples, but the relative abundance of these phyla differed significantly across these concentric zones. The diversity and composition of the soil bacterial community were found to be closely correlated with soil pH. Variance partitioning analysis suggested that urban ring roads contributed 5.95% of the bacterial community variation, and soil environmental factors explained 17.65% of the variation. The results of the current work indicate that urban development can alter the composition and diversity of the soil microbial community, and showed pH to be a key factor in the shaping of the composition of the soil bacterial community. Urban development did have a strong impact on the bacterial community of urban soil in Beijing. PMID:27934957

  19. Anti-Pseudomonas aeruginosa IgY Antibodies Induce Specific Bacterial Aggregation and Internalization in Human Polymorphonuclear Neutrophils

    PubMed Central

    Thomsen, K.; Christophersen, L.; Bjarnsholt, T.; Jensen, P. Ø.; Moser, C.

    2015-01-01

    Polymorphonuclear neutrophils (PMNs) are essential cellular constituents in the innate host response, and their recruitment to the lungs and subsequent ubiquitous phagocytosis controls primary respiratory infection. Cystic fibrosis pulmonary disease is characterized by progressive pulmonary decline governed by a persistent, exaggerated inflammatory response dominated by PMNs. The principal contributor is chronic Pseudomonas aeruginosa biofilm infection, which attracts and activates PMNs and thereby is responsible for the continuing inflammation. Strategies to prevent initial airway colonization with P. aeruginosa by augmenting the phagocytic competence of PMNs may postpone the deteriorating chronic biofilm infection. Anti-P. aeruginosa IgY antibodies significantly increase the PMN-mediated respiratory burst and subsequent bacterial killing of P. aeruginosa in vitro. The mode of action is attributed to IgY-facilitated formation of immobilized bacteria in aggregates, as visualized by fluorescence microscopy and the induction of increased bacterial hydrophobicity. Thus, the present study demonstrates that avian egg yolk immunoglobulins (IgY) targeting P. aeruginosa modify bacterial fitness, which enhances bacterial killing by PMN-mediated phagocytosis and thereby may facilitate a rapid bacterial clearance in airways of people with cystic fibrosis. PMID:25895968

  20. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  1. Solar wind precipitation on Mars

    NASA Astrophysics Data System (ADS)

    Stenberg, G.; Dieval, C.; Nilsson, H.; Kallio, E.; Barabash, S.; Futaana, Y.; Shematovich, V.; Bisikalo, D.

    2011-10-01

    We have found that solar wind particles frequently precipitate onto the atmosphere of Mars [1,2]. The precipitating particles contribute to the energy and matter flux into the ionosphere. We use ion data from the ASPERA-3 instrument onboard Mars Express to investigate the precipitation patterns, processes and the total transfer of energy and matter from the solar wind to the atmosphere. The main reason for the proton and alpha particle precipitation is likely the large gyroradii of hot particles compared to the size of the induced magnetosphere/magnetic barrier. We find that the particle penetration depends on the direction of the convection electric field in the solar wind but that the crustal magnetic fields have very little influence. The total energy flux is low compared to the solar radiation heating on the dayside, but a significant energy source on the nightside. We also believe that the solar wind alphaparticles precipitating into the atmosphere is an important source of the neutral helium in the Martian atmosphere. We combine our observations with computer modeling [3,4]. We have applied a Direct Simulation Monte Carlo method to solve the kinetic equation for the H/H+ transport in the upper Martian atmosphere including CO2, N2 and O. We conclude that the induced magnetic field around Mars plays the crucial role in the transport of charged particles in the upper atmosphere, and it determines the energy deposition of the solar wind.

  2. Bacterial Sialidase

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Data shows that elevated sialidase in bacterial vaginosis patients correlates to premature births in women. Bacterial sialidase also plays a significant role in the unusual colonization of Pseudomonas aeruginosa in cystic fibrosis patients. Crystals of Salmonella sialidase have been reproduced and are used for studying the inhibitor-enzyme complexes. These inhibitors may also be used to inhibit a trans-sialidase of Trypanosome cruzi, a very similar enzyme to bacterial sialidase, therefore preventing T. cruzi infection, the causitive agent of Chagas' disease. The Center for Macromolecular Crystallography suggests that inhibitors of bacterial sialidases can be used as prophylactic drugs to prevent bacterial infections in these critical cases.

  3. Does virus-induced lysis contribute significantly to bacterial mortality in the oxygenated sediment layer of shallow oxbow lakes?

    PubMed

    Fischer, Ulrike R; Wieltschnig, Claudia; Kirschner, Alexander K T; Velimirov, Branko

    2003-09-01

    Despite the recognition that viruses are ubiquitous components of aquatic ecosystems, the number of studies on viral abundance and the ecological role of viruses in sediments is scarce. In this investigation, the interactions between viruses and bacteria were studied in the oxygenated silty sediment layer of a mesotrophic oxbow lake. A long-term study (13 months) and a diel study revealed that viruses are a numerically important and dynamic component of the microbial community. The abundance and decay rates ranged from 4.3 x 10(9) to 7.2 x 10(9) particles ml of wet sediment(-1) and from undetectable to 22.2 x 10(7) particles ml(-1) h(-1), respectively, and on average the values were 2 orders of magnitude higher than the values for the overlying water. In contrast to our expectations, viruses did not contribute significantly to the bacterial mortality in the sediment, since on average only 6% (range, 0 to 25%) of the bacterial secondary production was controlled by viruses. The low impact of viruses on the bacterial community may be associated with the quantitatively low viral burden that benthic bacteria have to cope with compared to the viral burden with which bacterial assemblages in the water column are confronted. The virus-to-bacterium ratio of the sediment varied between 0.9 and 3.2, compared to a range of 5.0 to 12.4 obtained for the water column. We speculate that despite high numbers of potential hosts, the possibility of encountering a host cell is limited by the physical conditions in the sediment, which is therefore not a favorable environment for viral proliferation. Our data suggest that viruses do not play an important role in the processing and transfer of bacterial carbon in the oxygenated sediment layer of the environment investigated.

  4. Activity of Uncleaved Caspase-8 Controls Anti-bacterial Immune Defense and TLR-Induced Cytokine Production Independent of Cell Death

    PubMed Central

    DeLaney, Alexandra; Santos-Marrero, Melanie; Grier, Jennifer T.; Sun, Yan; Zwack, Erin E.; Hu, Baofeng; Olsen, Tayla M.; Rongvaux, Anthony; López, Carolina B.; Oberst, Andrew; Beiting, Daniel P.; Brodsky, Igor E.

    2016-01-01

    Caspases regulate cell death programs in response to environmental stresses, including infection and inflammation, and are therefore critical for the proper operation of the mammalian immune system. Caspase-8 is necessary for optimal production of inflammatory cytokines and host defense against infection by multiple pathogens including Yersinia, but whether this is due to death of infected cells or an intrinsic role of caspase-8 in TLR-induced gene expression is unknown. Caspase-8 activation at death signaling complexes results in its autoprocessing and subsequent cleavage and activation of its downstream apoptotic targets. Whether caspase-8 activity is also important for inflammatory gene expression during bacterial infection has not been investigated. Here, we report that caspase-8 plays an essential cell-intrinsic role in innate inflammatory cytokine production in vivo during Yersinia infection. Unexpectedly, we found that caspase-8 enzymatic activity regulates gene expression in response to bacterial infection as well as TLR signaling independently of apoptosis. Using newly-generated mice in which caspase-8 autoprocessing is ablated (Casp8DA/DA), we now demonstrate that caspase-8 enzymatic activity, but not autoprocessing, mediates induction of inflammatory cytokines by bacterial infection and a wide variety of TLR stimuli. Because unprocessed caspase-8 functions in an enzymatic complex with its homolog cFLIP, our findings implicate the caspase-8/cFLIP heterodimer in control of inflammatory cytokines during microbial infection, and provide new insight into regulation of antibacterial immune defense. PMID:27737018

  5. IgG against specific bacterial antigens in obese patients with diabetes and in mice with diet-induced obesity and glucose intolerance

    PubMed Central

    Mohammed, Nadeem; Tang, Lihua; Jahangiri, Anisa; de Villiers, Willem; Eckhardt, Erik

    2012-01-01

    OBJECTIVE High fat diets increase the risk for insulin resistance by promoting inflammation. The cause of inflammation is unclear, but germfree mouse studies have implicated commensal gut bacteria. We tested whether diet-induced obesity, diabetes, and inflammation are associated with anti-bacterial IgG. MATERIALS/METHODS Blood from lean and obese healthy volunteers or obese patients with diabetes were analyzed by ELISA for IgG against extracts of potentially pathogenic and pro-biotic strains of Escherichia coli (LF-82 and Nissle), Bacteroides thetaiotaomicron, and Lactobacillus acidophilus, and for circulating Tumor Necrosis Factor α (TNFα). C57Bl/6 mice were fed low- or high- fat diets (10 or 60% kcal from fat) for 10 weeks and tested for anti-bacterial IgG, bodyweight, fasting glucose, and inflammation. RESULTS Obese diabetic patients had significantly more IgG against extracts of E. coli LF-82 compared with lean controls, whereas IgG against extracts of the other bacteria was unchanged. Circulating TNFα was elevated and correlated with IgG against the LF-82 extract. Mice fed high-fat diets had increased fasting glucose levels, elevated TNFα and neutrophils, and significantly more IgG against the LF-82 extracts. CONCLUSIONS Diabetes in obesity is characterized by increased IgG against specific bacterial antigens. Specific commensal bacteria may mediate inflammatory effects of high-fat diets. PMID:22424821

  6. Short-chain inulin-like fructans reduce endotoxin and bacterial translocations and attenuate development of TNBS-induced colitis in rats.

    PubMed

    Ito, Hiroyuki; Tanabe, Hiroki; Kawagishi, Hirokazu; Tadashi, Wada; Yasuhiko, Tomono; Sugiyama, Kimio; Kiriyama, Shuhachi; Morita, Tatsuya

    2009-10-01

    Anti-inflammatory effects of short-chain inulin-like fructans (SCF) on trinitrobenzene sulfonic acid (TNBS)-induced colitis were investigated in rats, focusing specifically on endotoxin and bacterial translocations. SCF with degrees of polymerization (DP) of 4 and 8 were used. Rats were fed either control diet or diets including 60 g DP4 or DP8 per kilogram for 7 days, and then received intracolonic TNBS and were fed the respective diets for a further 10 days. DP4 and DP8 significantly reduced colonic injuries as assessed by damage score, but the reduction of colonic myeloperoxidase activity was manifest solely with DP8. At 3 days after colitis induction, bacterial translocation to the mesenteric lymph node was significantly lower in the DP4 and DP8 groups, but significant reduction in the portal endotoxin concentration was achieved solely in the DP8 group. Immediately prior to colitis induction, cecal immunoglobulin A and mucin concentrations were higher in the DP4 and DP8 groups, but these changes were abolished at 10 days post colitis induction. The data suggest that SCF exert prophylactic effects against TNBS colitis, presumably as a result of inhibitory effects on endotoxin and bacterial translocations.

  7. D-Psicose induces upregulation of defense-related genes and resistance in rice against bacterial blight.

    PubMed

    Kano, Akihito; Hosotani, Kouji; Gomi, Kenji; Yamasaki-Kokudo, Yumiko; Shirakawa, Chikage; Fukumoto, Takeshi; Ohtani, Kouhei; Tajima, Shigeyuki; Izumori, Ken; Tanaka, Keiji; Ishida, Yutaka; Nishizawa, Yoko; Ichimura, Kazuya; Tada, Yasuomi; Akimitsu, Kazuya

    2011-10-15

    We examined rice responses to a rare sugar, d-psicose. Rice growth was inhibited by d-psicose but not by common sugars. Microarray analysis revealed that d-psicose treatment caused an upregulation of many defense-related genes in rice, and dose-dependent upregulation of these genes was confirmed by quantitative reverse-transcription polymerase chain reaction. The level of upregulation of defense-related genes by d-psicose was low compared with that by d-allose, which is another rare sugar known to confer induction of resistance to rice bacterial blight in rice. Treatment with d-psicose conferred resistance to bacterial blight in rice in a dose-dependent manner, and the results indicate that d-psicose might be a candidate plant activator for reducing disease development in rice.

  8. Two poplar-associated bacterial isolates induce additive favorable responses in a constructed plant-microbiome system

    SciTech Connect

    Jawdy, Sara S.; Gunter, Lee E.; Engle, Nancy L.; Yang, Zamin Koo; Lu, Tse-Yuan S.; Tschaplinski, Timothy J.; Tuskan, Gerald A.; Doktycz, Mitchel John; Pelletier, Dale A.; Weston, David J.; Timm, Colin M.; Henning, Jeremiah A.; Aufrecht, Jayde; Gee, Emily; Nookaew, Intawat

    2016-04-26

    Here, the biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. In this work we study the function of a simplified community consisting of Pseudomonas and Burkholderia bacterial strains isolated from Populus hosts and inoculated on axenic Populus cutting in controlled laboratory conditions. Inoculation individually with either bacterial isolate increased root growth relative to uninoculated controls. Root area, photosynthetic efficiency, gene expression and metabolite expression data in individual and dual inoculated treatments indicate that the effects of these bacteria are unique and additive, suggesting that the function of a microbiome community may be predicted from the additive functions of the individual members.

  9. Two poplar-associated bacterial isolates induce additive favorable responses in a constructed plant-microbiome system

    DOE PAGES

    Jawdy, Sara S.; Gunter, Lee E.; Engle, Nancy L.; ...

    2016-04-26

    Here, the biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. In this work we study the function of a simplified community consisting of Pseudomonas and Burkholderia bacterial strains isolated from Populus hosts and inoculated on axenic Populus cutting in controlled laboratory conditions. Inoculation individually with either bacterial isolate increased root growth relative to uninoculated controls. Root area, photosynthetic efficiency, gene expression and metabolite expression data in individual and dual inoculated treatments indicate that the effects of these bacteria are unique and additive, suggesting that the function of a microbiome communitymore » may be predicted from the additive functions of the individual members.« less

  10. Two Poplar-Associated Bacterial Isolates Induce Additive Favorable Responses in a Constructed Plant-Microbiome System

    PubMed Central

    Timm, Collin M.; Pelletier, Dale A.; Jawdy, Sara S.; Gunter, Lee E.; Henning, Jeremiah A.; Engle, Nancy; Aufrecht, Jayde; Gee, Emily; Nookaew, Intawat; Yang, Zamin; Lu, Tse-Yuan; Tschaplinski, Timothy J.; Doktycz, Mitchel J.; Tuskan, Gerald A.; Weston, David J.

    2016-01-01

    The biological function of the plant-microbiome system is the result of contributions from the host plant and microbiome members. The Populus root microbiome is a diverse community that has high abundance of β- and γ-Proteobacteria, both classes which include multiple plant-growth promoting representatives. To understand the contribution of individual microbiome members in a community, we studied the function of a simplified community consisting of Pseudomonas and Burkholderia bacterial strains isolated from Populus hosts and inoculated on axenic Populus cutting in controlled laboratory conditions. Both strains increased lateral root formation and root hair production in Arabidopsis plate assays and are predicted to encode for different functions related to growth and plant growth promotion in Populus hosts. Inoculation individually, with either bacterial isolate, increased root growth relative to uninoculated controls, and while root area was increased in mixed inoculation, the interaction term was insignificant indicating additive effects of root phenotype. Complementary data including photosynthetic efficiency, whole-transcriptome gene expression and GC-MS metabolite expression data in individual and mixed inoculated treatments indicate that the effects of these bacterial strains are unique and additive. These results suggest that the function of a microbiome community may be predicted from the additive functions of the individual members. PMID:27200001

  11. Precipitation Climate Data Records

    NASA Astrophysics Data System (ADS)

    Nelson, B. R.; Prat, O.; Vasquez, L.

    2015-12-01

    Five precipitation CDRs are now or soon will be transitioned to NOAA's CDR program. These include the PERSIANN data set, which is a 30-year record of daily adjusted global precipitation based on retrievals from satellite microwave data using artificial neural networks. The AMSU-A/B/Hydrobundle is an 11-year record of precipitable water, cloud water, ice water, and other variables. CMORPH (the NOAA Climate Prediction Center Morphing Technique) is a 17-year record of daily and sub-daily adjusted global precipitation measured from passive microwave and infrared data at high spatial and temporal resolution. GPCP (the Global Precipitation Climatology Project) is an approximately 30-year record of monthly and pentad adjusted global precipitation and a 17-year record of daily adjusted global precipitation. The NEXRAD Reanalysis is a 10-year record of high resolution NEXRAD radar based adjusted CONUS-wide hourly and daily precipitation. This study provides an assessment of the existing and transitioned long term precipitation CDRs and includes the verification of the five precipitation CDRs using various methods including comparison with in-situ data sets and trend analysis. As all of the precipitation related CDRs are transitioned, long term analyses can be performed. Comparisons at varying scales (hourly, daily and longer) of the precipitation CDRs with in-situ data sets are provided as well as a first look at what could be an ensemble long term precipitation data record.

  12. Fluoride exposure abates pro-inflammatory response and induces in vivo apoptosis rendering zebrafish (Danio rerio) susceptible to bacterial infections.

    PubMed

    Singh, Rashmi; Khatri, Preeti; Srivastava, Nidhi; Jain, Shruti; Brahmachari, Vani; Mukhopadhyay, Asish; Mazumder, Shibnath

    2017-02-20

    The present study describes the immunotoxic effect of chronic fluoride exposure on adult zebrafish (Danio rerio). Zebrafish were exposed to fluoride (71.12 mg/L; 1/10 LC50) for 30 d and the expression of selected genes studied. We observed significant elevation in the detoxification pathway gene cyp1a suggesting chronic exposure to non-lethal concentration of fluoride is indeed toxic to fish. Fluoride mediated pro-oxidative stress is implicated with the downregulation in superoxide dismutase 1 and 2 (sod1/2) genes. Fluoride affected DNA repair machinery by abrogating the expression of the DNA repair gene rad51 and growth arrest and DNA damage inducible beta a gene gadd45ba. The upregulated expression of casp3a coupled with altered Bcl-2 associated X protein/B-cell lymphoma 2 ratio (baxa/bcl2a) clearly suggested chronic fluoride exposure induced the apoptotic cascade in zebrafish. Fluoride-exposed zebrafish when challenged with non-lethal dose of fish pathogen A. hydrophila revealed gross histopathology in spleen, bacterial persistence and significant mortality. We report that fluoride interferes with system-level output of pro-inflammatory cytokines tumour necrosis factor-α, interleukin-1β and interferon-γ, as a consequence, bacteria replicate efficiently causing significant fish mortality. We conclude, chronic fluoride exposure impairs the redox balance, affects DNA repair machinery with pro-apoptotic implications and suppresses pro-inflammatory cytokines expression abrogating host immunity to bacterial infections.

  13. Two outer membrane lipoproteins from Histophilus somni are immunogenic in rabbits and sheep and induce protection against bacterial challenge in mice.

    PubMed

    Guzmán-Brambila, Carolina; Rojas-Mayorquín, Argelia E; Flores-Samaniego, Beatriz; Ortuño-Sahagún, Daniel

    2012-11-01

    Histophilus somni is an economically important pathogen of cattle and other ruminants and is considered one of the key components of the bovine respiratory disease (BRD) complex, the leading cause of economic loss in the livestock industry. BRD is a multifactorial syndrome, in which a triad of agents, including bacteria, viruses, and predisposing factors or "stressors," combines to induce disease. Although vaccines against H. somni have been used for many decades, traditional bacterins have failed to demonstrate effective protection in vaccinated animals. Hence, the BRD complex continues to produce strong adverse effects on the health and well-being of stock and feeder cattle. The generation of recombinant proteins may facilitate the development of more effective vaccines against H. somni, which could confer better protection against BRD. In the present study, primers were designed to amplify, clone, express, and purify two recombinant lipoproteins from H. somni, p31 (Plp4) and p40 (LppB), which are structural proteins of the outer bacterial membrane. The results presented here demonstrate, to our knowledge for the first time, that when formulated, an experimental vaccine enriched with these two recombinant lipoproteins generates high antibody titers in rabbits and sheep and exerts a protective effect in mice against septicemia induced by H. somni bacterial challenge.

  14. An antisense peptide nucleic acid against Pseudomonas aeruginosa inhibiting bacterial-induced inflammatory responses in the cystic fibrosis IB3-1 cellular model system.

    PubMed

    Montagner, Giulia; Bezzerri, Valentino; Cabrini, Giulio; Fabbri, Enrica; Borgatti, Monica; Lampronti, Ilaria; Finotti, Alessia; Nielsen, Peter E; Gambari, Roberto

    2017-02-03

    Discovery of novel antimicrobial agents against Pseudomonas aeruginosa able to inhibit bacterial growth as well as the resulting inflammatory response is a key goal in cystic fibrosis research. We report in this paper that a peptide nucleic acid (PNA3969) targeting the translation initiation region of the essential acpP gene of P. aeruginosa, and previously shown to inhibit bacterial growth, concomitantly also strongly inhibits PAO1 induced up-regulation of the pro-inflammatory markers IL-8, IL-6, G-CSF, IFN-γ, IP-10, MCP-1 and TNF-α in IB3-1 cystic fibrosis cells infected by P. aeruginosa PAO1. Remarkably, no effect on PAO1 induction of VEGF, GM-CSF and IL-17 was observed. Analogous experiments using a two base mis-match control PNA did not show such inhibition. Furthermore, no significant effects of the PNAs were seen on cell growth, apoptosis or secretome profile in uninfected IB3-1 cells (with the exception of a PNA-mediated up-regulation of PDGF, IL-17 and GM-CSF). Thus, we conclude that in cell culture an antimicrobial PNA against Pseudomonas can inhibit the expression of pro-inflammatory cytokines otherwise induced by the infection. In particular, the effects of PNA-3969 on IL-8 gene expression are significant considering the key role of this protein in the cystic fibrosis inflammatory process exacerbated by P. aeruginosa infection.

  15. Two Outer Membrane Lipoproteins from Histophilus somni Are Immunogenic in Rabbits and Sheep and Induce Protection against Bacterial Challenge in Mice

    PubMed Central

    Guzmán-Brambila, Carolina; Rojas-Mayorquín, Argelia E.; Flores-Samaniego, Beatriz

    2012-01-01

    Histophilus somni is an economically important pathogen of cattle and other ruminants and is considered one of the key components of the bovine respiratory disease (BRD) complex, the leading cause of economic loss in the livestock industry. BRD is a multifactorial syndrome, in which a triad of agents, including bacteria, viruses, and predisposing factors or “stressors,” combines to induce disease. Although vaccines against H. somni have been used for many decades, traditional bacterins have failed to demonstrate effective protection in vaccinated animals. Hence, the BRD complex continues to produce strong adverse effects on the health and well-being of stock and feeder cattle. The generation of recombinant proteins may facilitate the development of more effective vaccines against H. somni, which could confer better protection against BRD. In the present study, primers were designed to amplify, clone, express, and purify two recombinant lipoproteins from H. somni, p31 (Plp4) and p40 (LppB), which are structural proteins of the outer bacterial membrane. The results presented here demonstrate, to our knowledge for the first time, that when formulated, an experimental vaccine enriched with these two recombinant lipoproteins generates high antibody titers in rabbits and sheep and exerts a protective effect in mice against septicemia induced by H. somni bacterial challenge. PMID:22971783

  16. The Bacterial Preparation OK432 Induces IL-12p70 Secretion in Human Dendritic Cells in a TLR3 Dependent Manner

    PubMed Central

    Hovden, Arnt-Ove; Karlsen, Marie; Jonsson, Roland; Appel, Silke

    2012-01-01

    Dendritic cells (DC) used in therapeutic cancer immunotherapy have to be able to stimulate T cells resulting in an immune response that can efficiently target the cancer cells. One of the critical hurdles has been the lack of IL-12p70 production when maturating the DC, which is rectified by using the bacterial preparation OK432 (trade name Picibanil) to mature the cells. In order to identify the mechanism behind OK432 stimulation of DC, we investigated the contribution of different TLR to examine their involvement in IL-12p70 production. By combining different inhibitors of TLR signaling, we demonstrate here that TLR3 is responsible for the IL-12p70 production of DC induced by OK432. Moreover, our data suggest that the ligand triggering IL-12p70 secretion upon TLR3 stimulation is sensitive to proteinase and partly also RNAse treatment. The fact that a bacterial compound like OK432 can activate the TLR3 pathway in human DC is a novel finding. OK432 demonstrates a critical ability to induce IL-12p70 production, which is of great relevance in DC based cancer immunotherapy. PMID:22363584

  17. The bacterial preparation OK432 induces IL-12p70 secretion in human dendritic cells in a TLR3 dependent manner.

    PubMed

    Hovden, Arnt-Ove; Karlsen, Marie; Jonsson, Roland; Appel, Silke

    2012-01-01

    Dendritic cells (DC) used in therapeutic cancer immunotherapy have to be able to stimulate T cells resulting in an immune response that can efficiently target the cancer cells. One of the critical hurdles has been the lack of IL-12p70 production when maturating the DC, which is rectified by using the bacterial preparation OK432 (trade name Picibanil) to mature the cells. In order to identify the mechanism behind OK432 stimulation of DC, we investigated the contribution of different TLR to examine their involvement in IL-12p70 production. By combining different inhibitors of TLR signaling, we demonstrate here that TLR3 is responsible for the IL-12p70 production of DC induced by OK432. Moreover, our data suggest that the ligand triggering IL-12p70 secretion upon TLR3 stimulation is sensitive to proteinase and partly also RNAse treatment. The fact that a bacterial compound like OK432 can activate the TLR3 pathway in human DC is a novel finding. OK432 demonstrates a critical ability to induce IL-12p70 production, which is of great relevance in DC based cancer immunotherapy.

  18. Nutritional Models of Experimentally-Induced Subacute Ruminal Acidosis (SARA) Differ in Their Impact on Rumen and Hindgut Bacterial Communities in Dairy Cows

    PubMed Central

    Plaizier, Jan C.; Li, Shucong; Tun, Hein M.; Khafipour, Ehsan

    2017-01-01

    Effects of subacute ruminal acidosis (SARA) challenges on the bacteria in rumen fluid, cecal digesta, and feces of dairy cows were determined using 16S rRNA gene pyrosequencing and real-time quantitative PCR. Six non-lactating Holstein cows with cannulas in the rumen and cecum were used in a 3 × 3 Latin square arrangement of treatments. During the first 3 wk of each experimental period, cows received a control diet containing 70% forages on a dry matter (DM) basis. In wk 4 of each period, cows received one of three diets: (1) the control diet; (2) a diet in which 34% of the dietary DM was replaced with pellets of ground wheat and barley (GBSC); or (3) a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen fluid, cecal digesta and feces were collected on d 5 of wk 4 of each period and the composition of the bacterial community was studied. Rumen fermentation responses were reported in a companion study. Both SARA-inducing challenges resulted in similar digesta pH depressions (as shown by the companion study), and reduced bacterial richness and diversity in rumen fluid, but GBSC had the larger effect. None of the challenges affected these measures in cecal digesta, and only GBSC reduced bacterial richness and diversity in feces. Only GBSC reduced the abundance of Bacteroidetes in rumen fluid. Abundances of limited number of bacterial genera identified by 16S rRNA gene sequencing in the rumen, cecum and feces were affected by the GBSC. The APSC did not affect any of these abundances. Both challenges increased the abundances of several starch, pectin, xylan, dextrin, lactate, succinate, and sugar fermenting bacterial species in the rumen, cecum, and feces as determined by qPCR. Only GBSC increased that of Megasphaera elsdenii in the rumen. Both challenges decreased the abundance of Streptococcus bovis, and increased that of Escherichia coli, in cecal digesta and feces, with GBSC having the larger effect. These results showed that

  19. Treatment of Amaranthus cruentus with chemical and biological inducers of resistance has contrasting effects on fitness and protection against compatible Gram positive and Gram negative bacterial pathogens.

    PubMed

    Casarrubias-Castillo, Kena; Martínez-Gallardo, Norma A; Délano-Frier, John P

    2014-07-01

    Amaranthus cruentus (Ac) plants were treated with the synthetic systemic acquired resistance (SAR) inducer benzothiadiazole (BTH), methyl jasmonate (MeJA) and the incompatible pathogen, Pseudomonas syringae pv. syringae (Pss), under greenhouse conditions. The treatments induced a set of marker genes in the absence of pathogen infection: BTH and Pss similarly induced genes coding for pathogenesis-related and antioxidant proteins, whereas MeJA induced the arginase, LOX2 and amarandin 1 genes. BTH and Pss were effective when tested against the Gram negative pathogen Ps pv. tabaci (Pst), which was found to have a compatible interaction with grain amaranth. The resistance response appeared to be salicylic acid-independent. However, resistance against Clavibacter michiganensis subsp. michiganensis (Cmm), a Gram positive tomato pathogen also found to infect Ac, was only conferred by Pss, while BTH increased susceptibility. Conversely, MeJA was ineffective against both pathogens. Induced resistance against Pst correlated with the rapid and sustained stimulation of the above genes, including the AhPAL2 gene, which were expressed both locally and distally. The lack of protection against Cmm provided by BTH, coincided with a generalized down-regulation of defense gene expression and chitinase activity. On the other hand, Pss-treated Ac plants showed augmented expression levels of an anti-microbial peptide gene and, surprisingly, of AhACCO, an ethylene biosynthetic gene associated with susceptibility to Cmm in tomato, its main host. Pss treatment had no effect on productivity, but compromised growth, whereas MeJA reduced yield and harvest index. Conversely, BTH treatments led to smaller plants, but produced significantly increased yields. These results suggest essential differences in the mechanisms employed by biological and chemical agents to induce SAR in Ac against bacterial pathogens having different infection strategies. This may determine the outcome of a particular

  20. Precipitation-Induced Changes in Microstrain and Its Relation with Hardness and Tempering Parameter in 17-4 PH Stainless Steel

    NASA Astrophysics Data System (ADS)

    Mahadevan, S.; Manojkumar, R.; Jayakumar, T.; Das, C. R.; Rao, B. P. C.

    2016-06-01

    17-4 PH (precipitation hardening) stainless steel is a soft martensitic stainless steel strengthened by aging at appropriate temperature for sufficient duration. Precipitation of copper particles in the martensitic matrix during aging causes coherency strains which improves the mechanical properties, namely hardness and strength of the matrix. The contributions to X-ray diffraction (XRD) profile broadening due to coherency strains caused by precipitation and crystallite size changes due to aging are separated and quantified using the modified Williamson-Hall approach. The estimated normalized mean square strain and crystallite size are used to explain the observed changes in hardness. Microstructural changes observed in secondary electron images are in qualitative agreement with crystallite size changes estimated from XRD profile analysis. The precipitation kinetics in the age-hardening regime and overaged regime are studied from hardness changes and they follow the Avrami kinetics and Wilson's model, respectively. In overaged condition, the hardness changes are linearly correlated to the tempering parameter (also known as Larson-Miller parameter). Similar linear variation is observed between the normalized mean square strain (determined from XRD line profile analysis) and the tempering parameter, in the incoherent regime which is beyond peak microstrain conditions.

  1. Polarized light scattering as a means of detecting heat and UV-induced changes in bacteria and bacterial spores

    NASA Astrophysics Data System (ADS)

    Van De Merwe, Willem P.; Bronk, Burt V.

    1993-07-01

    In the present paper we report on initial attempts to correlate changes in polarized light scattering signals from bacteria and bacterial spores with changes in physical parameters as a result of heat and UV exposure. Clear reproducible changes can be observed, but quantitative correlation such as measuring the degree of germination or survivability needs further study. Average cell size changes can be measured quickly in bacteria such as after UV exposure or during the growth cycle, making the used technique very valuable to monitor changes. Computer modelling is needed to distinguish effects caused by size changes and by changes in index of refraction.

  2. The El Niño Southern Oscillation (ENSO) induced modulations in precipitation and nitrogen wet deposition rates in the continental United States

    NASA Astrophysics Data System (ADS)

    Nergui, T.; Chung, S. H.; Adam, J. C.; Evans, R. D.

    2015-12-01

    The ENSO affects atmospheric nitrogen (N) deposition rates through its modulation on N wet deposition. Precipitation and wet deposition measurements at 151 sites of the National Atmospheric Deposition Program/National Trends Network and the NINO3.4 SST climate index from the NOAA's Climate Prediction Center are analyzed to determine the impacts of the ENSO on N wet deposition and precipitation rates in the continental U.S. Precipitation and N wet deposition time series are dominated by high frequency components; however, they contain a wide range of inter-annual frequency components depending on the location. At the 2-to 6-year timescale, variability of precipitation and N wet deposition rates in the Pacific Northwest, the Rocky Mountains, the Gulf States, the Northeast, and the Great Lakes regions are correlated with that of the NINO3.4 index (r2= 0.09-0.59 for precipitation and r2= 0.09-0.52 for N wet deposition, p<0.05). The spatial patterns and strength of the correlations vary by region and season. The correlations are the strongest and most spatially extensive during winter; 46-62% and 46-53% of the 2- to 6-year variability of precipitation and N wet deposition rates in the Rocky Mountains, the Gulf of Mexico, and near the Great Lakes can be explained by ENSO activity. The wintertime relationships tend to hold through springtime in the Great Lakes, the Ohio River Valley, and the Northeast. During the El Niño winters and springs, N wet deposition rates are higher than normal (greater than the 70thpercentile) in the southern Great Plains and the Gulf Coast. Winter and spring La Niña episodes bring precipitation and N wet deposition rates above normal over the Cascades, the Ohio River Valley, the Northeast and the Great Lakes regions. The ensemble mean of eleven coupled General Circulation Models (Yeh et al., 2009) shows that the weak ENSO cycles, having small to moderate amplitudes and reoccurring in shorter time intervals, are projected to dominate in the 21

  3. Signaling lymphocyte-activation molecule SLAMF1 augments mycobacteria BCG-induced inflammatory response and facilitates bacterial clearance.

    PubMed

    Song, Tengfei; Dong, Chunsheng; Xiong, Sidong

    2015-09-01

    Tuberculosis, which is caused by intracellular mycobacterium Mycobacterium tuberculosis (Mtb), remains one of the most serious global public health concerns. The mechanisms by which innate immunity regulates the inflammatory responses and affects mycobacterial infection remain unclear. In this study, signaling lymphocyte-activation molecule family 1 (SLAMF1) was significantly upregulated in Mycobacterium bovis Bacille Calmette-Guérin (BCG)-infected RAW264.7 cells. Overexpression of SLAMF1 significantly increased the production of inflammatory factors TNF-α and IL-1β, as well as chemokine MCP-1, both in vitro and in vivo upon mycobacteria BCG infection. By contrast, knockdown of SLAMF1 significantly decreased the production of TNF-α, IL-1β, and MCP-1. Western blot analysis indicated that the NF-κB signaling pathway may contribute to the elevated inflammatory response promoted by SLAMF1, as evidenced by higher levels of phosphorylated p65 and IκBα detected with SLAMF1 overexpression. Furthermore, SLAMF1 upregulation facilitated bacterial clearance in infected RAW264.7 cells and in the lungs of infected mice. In conclusion, we demonstrated that BCG infection significantly upregulated SLAMF1, which enhanced inflammatory response by activating the NF-κB signaling pathway and facilitated bacterial clearance in BCG-infected RAW264.7 cells and mice.

  4. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation.

    PubMed

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M; Gil, Francisco J; Rodriguez, Daniel

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria-cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties.

  5. TALE-induced bHLH transcription factors that activate a pectate lyase contribute to water soaking in bacterial spot of tomato

    PubMed Central

    Schwartz, Allison R.; Morbitzer, Robert; Lahaye, Thomas; Staskawicz, Brian J.

    2017-01-01

    AvrHah1 [avirulence (avr) gene homologous to avrBs3 and hax2, no. 1] is a transcription activator-like (TAL) effector (TALE) in Xanthomonas gardneri that induces water-soaked disease lesions on fruits and leaves during bacterial spot of tomato. We observe that water from outside the leaf is drawn into the apoplast in X. gardneri-infected, but not X. gardneriΔavrHah1 (XgΔavrHah1)-infected, plants, conferring a dark, water-soaked appearance. The pull of water can facilitate entry of additional bacterial cells into the apoplast. Comparing the transcriptomes of tomato infected with X. gardneri vs. XgΔavrHah1 revealed the differential up-regulation of two basic helix–loop–helix (bHLH) transcription factors with predicted effector binding elements (EBEs) for AvrHah1. We mined our RNA-sequencing data for differentially up-regulated genes that could be direct targets of the bHLH transcription factors and therefore indirect targets of AvrHah1. We show that two pectin modification genes, a pectate lyase and pectinesterase, are targets of both bHLH transcription factors. Designer TALEs (dTALEs) for the bHLH transcription factors and the pectate lyase, but not for the pectinesterase, complement water soaking when delivered by XgΔavrHah1. By perturbing transcriptional networks and/or modifying the plant cell wall, AvrHah1 may promote water uptake to enhance tissue damage and eventual bacterial egression from the apoplast to the leaf surface. Understanding how disease symptoms develop may be a useful tool for improving the tolerance of crops from damaging disease lesions. PMID:28100489

  6. Comprehensive Proteomic and Metabolomic Signatures of Nontypeable Haemophilus influenzae-Induced Acute Otitis Media Reveal Bacterial Aerobic Respiration in an Immunosuppressed Environment.

    PubMed

    Harrison, Alistair; Dubois, Laura G; St John-Williams, Lisa; Moseley, M Arthur; Hardison, Rachael L; Heimlich, Derek R; Stoddard, Alexander; Kerschner, Joseph E; Justice, Sheryl S; Thompson, J Will; Mason, Kevin M

    2016-03-01

    A thorough understanding of the molecular details of the interactions between bacteria and host are critical to ultimately prevent disease. Recent technological advances allow simultaneous analysis of host and bacterial protein and metabolic profiles from a single small tissue sample to provide insight into pathogenesis. We used the chinchilla model of human otitis media to determine, for the first time, the most expansive delineation of global changes in protein and metabolite profiles during an experimentally induced disease. After 48 h of infection with nontypeable Haemophilus influenzae, middle ear tissue lysates were analyzed by high-resolution quantitative two-dimensional liquid chromatography-tandem mass spectrometry. Dynamic changes in 105 chinchilla proteins and 66 metabolites define the early proteomic and metabolomic signature of otitis media. Our studies indicate that establishment of disease coincides with actin morphogenesis, suppression of inflammatory mediators, and bacterial aerobic respiration. We validated the observed increase in the actin-remodeling complex, Arp2/3, and experimentally showed a role for Arp2/3 in nontypeable Haemophilus influenzae invasion. Direct inhibition of actin branch morphology altered bacterial invasion into host epithelial cells, and is supportive of our efforts to use the information gathered to modify outcomes of disease. The twenty-eight nontypeable Haemophilus influenzae proteins identified participate in carbohydrate and amino acid metabolism, redox homeostasis, and include cell wall-associated metabolic proteins. Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Identification of

  7. 5-Aminoimidazole-4-carboxamide ribonucleoside-mediated adenosine monophosphate-activated protein kinase activation induces protective innate responses in bacterial endophthalmitis.

    PubMed

    Kumar, Ajay; Giri, Shailendra; Kumar, Ashok

    2016-12-01

    The retina is considered to be the most metabolically active tissue in the body. However, the link between energy metabolism and retinal inflammation, as incited by microbial infection such as endophthalmitis, remains unexplored. In this study, using a mouse model of Staphylococcus aureus (SA) endophthalmitis, we demonstrate that the activity (phosphorylation) of 5' adenosine monophosphate-activated protein kinase alpha (AMPKα), a cellular energy sensor and its endogenous substrate; acetyl-CoA carboxylase is down-regulated in the SA-infected retina. Intravitreal administration of an AMPK activator, 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), restored AMPKα and acetyl-CoA carboxylase phosphorylation. AICAR treatment reduced both the bacterial burden and intraocular inflammation in SA-infected eyes by inhibiting NF-kB and MAP kinases (p38 and JNK) signalling. The anti-inflammatory effects of AICAR were diminished in eyes pretreated with AMPK inhibitor, Compound C. The bioenergetics (Seahorse) analysis of SA-infected microglia and bone marrow-derived macrophages revealed an increase in glycolysis, which was reinstated by AICAR treatment. AICAR also reduced the expression of SA-induced glycolytic genes, including hexokinase 2 and glucose transporter 1 in microglia, bone marrow-derived macrophages and the mouse retina. Interestingly, AICAR treatment enhanced the bacterial phagocytic and intracellular killing activities of cultured microglia, macrophages and neutrophils. Furthermore, AMPKα1 global knockout mice exhibited increased susceptibility towards SA endophthalmitis, as evidenced by increased inflammatory mediators and bacterial burden and reduced retinal function. Together, these findings provide the first evidence that AMPK activation promotes retinal innate defence in endophthalmitis by modulating energy metabolism and that it can be targeted therapeutically to treat ocular infections.

  8. Comprehensive Proteomic and Metabolomic Signatures of Nontypeable Haemophilus influenzae-Induced Acute Otitis Media Reveal Bacterial Aerobic Respiration in an Immunosuppressed Environment*

    PubMed Central

    Harrison, Alistair; Dubois, Laura G.; St. John-Williams, Lisa; Moseley, M. Arthur; Hardison, Rachael L.; Heimlich, Derek R.; Stoddard, Alexander; Kerschner, Joseph E.; Justice, Sheryl S.; Thompson, J. Will; Mason, Kevin M.

    2016-01-01

    A thorough understanding of the molecular details of the interactions between bacteria and host are critical to ultimately prevent disease. Recent technological advances allow simultaneous analysis of host and bacterial protein and metabolic profiles from a single small tissue sample to provide insight into pathogenesis. We used the chinchilla model of human otitis media to determine, for the first time, the most expansive delineation of global changes in protein and metabolite profiles during an experimentally induced disease. After 48 h of infection with nontypeable Haemophilus influenzae, middle ear tissue lysates were analyzed by high-resolution quantitative two-dimensional liquid chromatography-tandem mass spectrometry. Dynamic changes in 105 chinchilla proteins and 66 metabolites define the early proteomic and metabolomic signature of otitis media. Our studies indicate that establishment of disease coincides with actin morphogenesis, suppression of inflammatory mediators, and bacterial aerobic respiration. We validated the observed increase in the actin-remodeling complex, Arp2/3, and experimentally showed a role for Arp2/3 in nontypeable Haemophilus influenzae invasion. Direct inhibition of actin branch morphology altered bacterial invasion into host epithelial cells, and is supportive of our efforts to use the information gathered to modify outcomes of disease. The twenty-eight nontypeable Haemophilus influenzae proteins identified participate in carbohydrate and amino acid metabolism, redox homeostasis, and include cell wall-associated metabolic proteins. Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Identification of

  9. Protective effect of p-methoxycinnamic acid, an active phenolic acid against 1,2-dimethylhydrazine-induced colon carcinogenesis: modulating biotransforming bacterial enzymes and xenobiotic metabolizing enzymes.

    PubMed

    Gunasekaran, Sivagami; Venkatachalam, Karthikkumar; Jeyavel, Kabalimoorthy; Namasivayam, Nalini

    2014-09-01

    Objective of the study is to evaluate the modifying potential of p-methoxycinnamic acid (p-MCA), an active rice bran phenolic acid on biotransforming bacterial enzymes and xenobiotic metabolizing enzymes in 1,2-dimethylhydrazine-induced rat colon carcinogenesis. 48 male albino wistar rats were divided into six groups. Group1 (control) received modified pellet diet and 0.1 % carboxymethylcellulose; group2 received modified pellet diet along with p-MCA (80 mg/kg b.wt. p.o.) everyday for 16 weeks; groups 3-6 received 1,2-dimethylhydrazine (DMH) (20 mg/kg b.wt.) subcutaneous injection once a week for the first 4 weeks, while groups 4-6 received p-MCA at three different doses of 20, 40 and 80 mg/kg b.wt. p.o. everyday for 16 weeks. A significant increase in carcinogen-activating enzymes (cytochrome P450, cytochrome b5, cytochrome P4502E1, NADH-cytochrome-b5-reductase and NADPH-cytochrome-P450 reductase) with concomitant decrease in phaseII enzymes, DT-Diaphorase, glutathione S-transferase, UDP-glucuronyl-transferase and gamma glutamyltransferase were observed in group3 compared to control. DMH treatment significantly increased the activities of feacal and colonic bacterial enzymes (β-glucosidase, β-galactosidase, β-glucuronidase, nitroreductase, sulphatase and mucinase). p-MCA supplementation (40 mg/kg b.wt) to carcinogen exposed rats inhibited these enzymes, which were near those of control rats. The formation of dysplastic aberrant crypt foci in the colon and the histopathological observations of the liver also supports our biochemical findings. p-MCA (40 mg/kg b.wt.) offers remarkable modulating efficacy of biotransforming bacterial and xenobiotic metabolizing enzymes in colon carcinogenesis.

  10. Effect of hesperetin, a citrus flavonoid, on bacterial enzymes and carcinogen-induced aberrant crypt foci in colon cancer rats: a dose-dependent study.

    PubMed

    Aranganathan, Selvaraj; Selvam, Jayabal Panneer; Nalini, Namasivayam

    2008-10-01

    Hesperetin, an important bioactive compound in Chinese traditional medicine, has antioxidant and anticarcinogenic properties. Hesperetin is found in abundance in orange and grape juices (200-590 mg L(-1)) consumed in the daily diet. We have investigated the effect of different doses of hesperetin on faecal and colonic mucosal bacterial enzymes and aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in male Wistar rats. The rats were divided into six groups and were fed a modified pellet diet for 16 weeks. Group 1 served as control and group 2 received the modified pellet diet along with hesperetin (30 mg kg(-1)). The rats in groups 3-6 rats were given a weekly subcutaneous injection of DMH (20 mg kg(-1)) for the first four weeks. Hesperetin was supplemented orally at different doses (10, 20 or 30 mg kg(-1)) for a total of 16 weeks. At the end of the experimental period all rats were killed. In DMH-treated rats, the activity of faecal and colonic mucosal bacterial enzymes, such as beta-glucuronidase, beta-galactosidase, beta-glucosidase, nitroreductase, sulfatase and mucinase, were significantly elevated, but in rats supplemented hesperetin along with DMH the activity was significantly lowered (P < 0.05). The total number of aberrant crypts was significantly increased in unsupplemented DMH-treated rats, while hesperetin supplementation to DMH-treated rats significantly reduced the total number of crypts. The results demonstrated that hesperetin supplementation at a dose of 20 mg kg(-1) played a potent role in suppressing the formation of aberrant crypt foci and reducing the activity of bacterial enzymes in colon cancer.

  11. Bacterial extracellular lignin peroxidase

    DOEpatents

    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.

  12. A Natural Bacterial-Derived Product, the Metalloprotease Arazyme, Inhibits Metastatic Murine Melanoma by Inducing MMP-8 Cross-Reactive Antibodies

    PubMed Central

    Pereira, Felipe V.; Ferreira-Guimarães, Carla A.; Paschoalin, Thaysa; Scutti, Jorge A. B.; Melo, Filipe M.; Silva, Luis S.; Melo, Amanda C. L.; Silva, Priscila; Tiago, Manoela; Matsuo, Alisson L.; Juliano, Luiz; Juliano, Maria A.; Carmona, Adriana K.; Travassos, Luiz R.; Rodrigues, Elaine G.

    2014-01-01

    The increased incidence, high rates of mortality and few effective means of treatment of malignant melanoma, stimulate the search for new anti-tumor agents and therapeutic targets to control this deadly metastatic disease. In the present work the antitumor effect of arazyme, a natural bacterial-derived metalloprotease secreted by Serratia proteomaculans, was investigated. Arazyme significantly reduced the number of pulmonary metastatic nodules after intravenous inoculation of B16F10 melanoma cells in syngeneic mice. In vitro, the enzyme showed a dose-dependent cytostatic effect in human and murine tumor cells, and this effect was associated to the proteolytic activity of arazyme, reducing the CD44 expression at the cell surface, and also reducing in vitro adhesion and in vitro/in vivo invasion of these cells. Arazyme treatment or immunization induced the production of protease-specific IgG that cross-reacted with melanoma MMP-8. In vitro, this antibody was cytotoxic to tumor cells, an effect increased by complement. In vivo, arazyme-specific IgG inhibited melanoma lung metastasis. We suggest that the antitumor activity of arazyme in a preclinical model may be due to a direct cytostatic activity of the protease in combination with the elicited anti-protease antibody, which cross-reacts with MMP-8 produced by tumor cells. Our results show that the bacterial metalloprotease arazyme is a promising novel antitumor chemotherapeutic agent. PMID:24788523

  13. Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens.

    PubMed

    Martínez, Isidoro; Oliveros, Juan C; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Menéndez, Margarita; Moranta, David; Nieto, Amelia; Ortín, Juan; Pérez-González, Alicia; Prat, Cristina; Ramos-Sevillano, Elisa; Regueiro, Verónica; Rodriguez-Frandsen, Ariel; Solís, Dolores; Yuste, José; Bengoechea, José A; Melero, José A

    2017-01-01

    Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here.

  14. Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens

    PubMed Central

    Martínez, Isidoro; Oliveros, Juan C.; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Men