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91.
The feasibility of aerobic in situ bioremediation isbeing investigated for use in a strategy to controlsubsurface coal tar contamination at the site of aformer manufactured gas plant. As part of thisinvestigation, anoxic aquifer sands collected between11 and 25 m below ground surface were assayed in batchmicrocosms to measure the singular and combinedeffects of O2, NO3
-, andPO4
3- on 14C-naphthalenemineralization. The influence of these additivesvaried considerably between sediments. A high initialconcentration of O2 (21 mg/L) promoted thegreatest extent of mineralization in the majority ofactive sediments. NO3
- (85 mg/L) wasobserved to enhance, inhibit, or have no effect on therate of naphthalene mineralization, althoughsignificant denitrification was observed in nearly allthe active sediments. Data suggest thatPO4
3- complexation and/or precipitation withsediment cations limited P bioavailability. Thesediments that were incapable of mineralizingnaphthalene were characterized by low pH (< 4.1),high SO4
2- (> 500 mg/L), and moderate tohigh dissolved Fe(II) (30–265 mg/L) whenequilibrated aerobically with water. Fe(II) likelyexerted a significant O2 demand that reduced theO2 available as an electron acceptor forbiodegradation. These experiments demonstrate thatwhile aeration/oxygenation can be an effectivestrategy for enhancing subsurface bioremediation ofaromatic hydrocarbons, the biodegradation response toaeration/oxygenation and nutrient addition may varyconsiderably within an aquifer. 相似文献
92.
Beatrijs L.P. Bloemers Chantal J.M. Broers Louis Bont Michel E. Weijerman Reinoud J.B.J. Gemke A. Marceline van Furth 《Microbes and infection / Institut Pasteur》2010,12(11):799-808
Down syndrome (DS) is the most common chromosomal abnormality among live-born infants. Respiratory tract infections are the most important cause of mortality in individuals with DS at all ages. In recent decades several studies have been performed to elucidate abnormalities of the immune system in DS. However, the influence of the immune system on the occurrence of respiratory tract infections in these children has never been reviewed. 相似文献
93.
Gosens R Stelmack GL Dueck G McNeill KD Yamasaki A Gerthoffer WT Unruh H Gounni AS Zaagsma J Halayko AJ 《American journal of physiology. Lung cellular and molecular physiology》2006,291(3):L523-L534
Chronic airways diseases, including asthma, are associated with an increased airway smooth muscle (ASM) mass, which may contribute to chronic airway hyperresponsiveness. Increased muscle mass is due, in part, to increased ASM proliferation, although the precise molecular mechanisms for this response are not completely clear. Caveolae, which are abundant in smooth muscle cells, are membrane microdomains where receptors and signaling effectors can be sequestered. We hypothesized that caveolae and caveolin-1 play an important regulatory role in ASM proliferation. Therefore, we investigated their role in p42/p44 MAPK signaling and proliferation using human ASM cell lines. Disruption of caveolae using methyl-beta-cyclodextrin and small interfering (si)RNA-knockdown of caveolin-1 caused spontaneous p42/p44 MAPK activation; additionally, caveolin-1 siRNA induced ASM proliferation in mitogen deficient conditions, suggesting a key role for caveolae and caveolin-1 in maintaining quiescence. Moreover, caveolin-1 accumulates twofold in myocytes induced to a contractile phenotype compared with proliferating ASM cells. Caveolin-1 siRNA failed to increase PDGF-induced p42/p44 MAPK activation and cell proliferation, however, indicating that PDGF stimulation actively reversed the antimitogenic control by caveolin-1. Notably, the PDGF induced loss of antimitogenic control by caveolin-1 coincided with a marked increase in caveolin-1 phosphorylation. Furthermore, the strong association of PDGF receptor-beta with caveolin-1 that exists in quiescent cells was rapidly and markedly reduced with agonist addition. This suggests a dynamic relationship in which mitogen stimulation actively reverses caveolin-1 suppression of p42/p44 MAPK signal transduction. As such, caveolae and caveolin-1 coordinate PDGF receptor signaling, leading to myocyte proliferation, and inhibit constitutive activity of p42/p44 MAPK to sustain cell quiescence. 相似文献
94.
Jin L Milazzo AC Kleinfelder S Li S Leblanc P Duttweiler F Bouwer JC Peltier ST Ellisman MH Xuong NH 《Journal of structural biology》2008,161(3):352-358
A prototype direct detection device (DDD) camera system has shown great promise in improving both the spatial resolution and the signal to noise ratio for electron microscopy at 120–400 keV beam energies (Xuong et al., 2007. Methods in Cell Biology, 79, 721–739). Without the need for a resolution-limiting scintillation screen as in the charge coupled device (CCD), the DDD camera can outperform CCD based systems in terms of spatial resolution, due to its small pixel size (5 μm). In this paper, the modulation transfer function (MTF) of the DDD prototype is measured and compared with the specifications of commercial scientific CCD camera systems. Combining the fast speed of the DDD with image mosaic techniques, fast wide-area imaging is now possible. In this paper, the first large area mosaic image and the first tomography dataset from the DDD camera are presented, along with an image processing algorithm to correct the specimen drift utilizing the fast readout of the DDD system. 相似文献
95.
Sean D. Moore Timothy Pittaway Gustav Bouwer Jeremy G. Fourie 《Biocontrol Science and Technology》2004,14(3):239-250
A concentration of 1.15×107 OBs/mL of HearNPV, sprayed using a knapsack, resulted in a 100% reduction in Helicoverpa armigera larval infestation within 7 days on tomato plants in a hot house environment. A 10-fold lower concentration, 1.15×106 OBs/mL, resulted in a 100% reduction within 16 days. These two concentrations reduced damage to tomatoes by 81 and 69%, respectively. In two field trials on navel oranges, the lower concentration and an additional even lower concentration of 7.26×105 OBs/mL, both resulted in a 100% reduction in H. armigera infestation within 14 days or longer. H. armigera damage to fruit was reduced by up to 84 and 75%, respectively, in the two trials. Rejection for export was reduced by 96 and 62%. This could imply a saving of US$339 per hectare compared to the untreated control. These results were better than those achieved with Bacillus thuringiensis and various standard chemical insecticides used in the same trials. Reasons for these results are discussed. 相似文献
96.
Dedmer Schaafsma Reinoud Gosens I Sophie T Bos Herman Meurs Johan Zaagsma S Adriaan Nelemans 《Respiratory research》2005,6(1):85
Background
In addition to their proliferative and differentiating effects, several growth factors are capable of inducing a sustained airway smooth muscle (ASM) contraction. These contractile effects were previously found to be dependent on Rho-kinase and have also been associated with the production of eicosanoids. However, the precise mechanisms underlying growth factor-induced contraction are still unknown. In this study we investigated the role of contractile prostaglandins and Rho-kinase in growth factor-induced ASM contraction.Methods
Growth factor-induced contractions of guinea pig open-ring tracheal preparations were studied by isometric tension measurements. The contribution of Rho-kinase, mitogen-activated protein kinase (MAPK) and cyclooxygenase (COX) to these reponses was established, using the inhibitors Y-27632 (1 μM), U-0126 (3 μM) and indomethacin (3 μM), respectively. The Rho-kinase dependency of contractions induced by exogenously applied prostaglandin F2α (PGF2α) and prostaglandin E2 (PGE2) was also studied. In addition, the effects of the selective FP-receptor antagonist AL-8810 (10 μM) and the selective EP1-antagonist AH-6809 (10 μM) on growth factor-induced contractions were investigated, both in intact and epithelium-denuded preparations. Growth factor-induced PGF2α-and PGE2-release in the absence and presence of Y-27632, U-0126 and indomethacin, was assessed by an ELISA-assay.Results
Epidermal growth factor (EGF)-and platelet-derived growth factor (PDGF)-induced contractions of guinea pig tracheal smooth muscle preparations were dependent on Rho-kinase, MAPK and COX. Interestingly, growth factor-induced PGF2α-and PGE2-release from tracheal rings was significantly reduced by U-0126 and indomethacin, but not by Y-27632. Also, PGF2α-and PGE2-induced ASM contractions were largely dependent on Rho-kinase, in contrast to other contractile agonists like histamine. The FP-receptor antagonist AL-8810 (10 μM) significantly reduced (approximately 50 %) and the EP1-antagonist AH-6809 (10 μM) abrogated growth factor-induced contractions, similarly in intact and epithelium-denuded preparations.Conclusion
The results indicate that growth factors induce ASM contraction through contractile prostaglandins – not derived from the epithelium – which in turn rely on Rho-kinase for their contractile effects. 相似文献97.
Schillace RV Andrews SF Galligan SG Burton KA Starks HJ Bouwer HG McKnight GS Davey MP Carr DW 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(11):6847-6853
Intracellular cAMP may inhibit T cell activation and proliferation via activation of the cAMP-dependent protein kinase, PKA. PKA signaling is maintained through interactions of the regulatory subunit with A-kinase anchoring proteins (AKAPs). We demonstrated that T cells contain AKAPs and now ask whether PKA anchoring to AKAPs via the RIIalpha regulatory subunit is necessary for cAMP-mediated inhibition of T cell activation. We studied the immune systems of mice lacking the RIIalpha regulatory subunit of PKA (-/-) and the ability of cells isolated from these mice to respond to cAMP. Dissection of spleen and thymus from wild-type (WT) and -/- mice, single cell suspensions generated from these organs, and flow cytometry analysis illustrate that the gross morphology, cell numbers, and cell populations in the spleen and thymus of the -/- mice are similar to WT controls. In vitro, splenocytes from -/- mice respond to anti-CD3/anti-CD28 and PMA/ionomycin stimulation and produce IL-2 similar to WT. Cytokine analysis revealed no significant difference in Th1 or Th2 differentiation. Finally, equivalent frequencies of CD8(+) IFN-gamma producing effector cells were stimulated upon infection of WT or -/- mice with Listeria monocytogenes. These data represent the first study of the role of RIIalpha in the immune system in vivo and provide evidence that T cell development, homeostasis, and the generation of a cell-mediated immune response are not altered in the RIIalpha -/- mice, suggesting either that RIIalpha is not required for normal immune function or that other proteins are able to compensate for RIIalpha function. 相似文献
98.
Ringelberg DB Talley JW Perkins EJ Tucker SG Luthy RG Bouwer EJ Fredrickson HL 《Applied and environmental microbiology》2001,67(4):1542-1550
Dredged harbor sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) was removed from the Milwaukee Confined Disposal Facility and examined for in situ biodegradative capacity. Molecular techniques were used to determine the successional characteristics of the indigenous microbiota during a 4-month bioslurry evaluation. Ester-linked phospholipid fatty acids (PLFA), multiplex PCR of targeted genes, and radiorespirometry techniques were used to define in situ microbial phenotypic, genotypic, and metabolic responses, respectively. Soxhlet extractions revealed a loss in total PAH concentrations of 52%. Individual PAHs showed reductions as great as 75% (i.e., acenapthene and fluorene). Rates of (14)C-PAH mineralization (percent/day) were greatest for phenanthrene, followed by pyrene and then chrysene. There was no mineralization capacity for benzo[a]pyrene. Ester-linked phospholipid fatty acid analysis revealed a threefold increase in total microbial biomass and a dynamic microbial community composition that showed a strong correlation with observed changes in the PAH chemistry (canonical r(2) of 0.999). Nucleic acid analyses showed copies of genes encoding PAH-degrading enzymes (extradiol dioxygenases, hydroxylases, and meta-cleavage enzymes) to increase by as much as 4 orders of magnitude. Shifts in gene copy numbers showed strong correlations with shifts in specific subsets of the extant microbial community. Specifically, declines in the concentrations of three-ring PAH moieties (i.e., phenanthrene) correlated with PLFA indicative of certain gram-negative bacteria (i.e., Rhodococcus spp. and/or actinomycetes) and genes encoding for naphthalene-, biphenyl-, and catechol-2,3-dioxygenase degradative enzymes. The results of this study suggest that the intrinsic biodegradative potential of an environmental site can be derived from the polyphasic characterization of the in situ microbial community. 相似文献
99.
Large‐scale image‐based profiling of single‐cell phenotypes in arrayed CRISPR‐Cas9 gene perturbation screens
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Reinoud de Groot Joel Lüthi Helen Lindsay René Holtackers Lucas Pelkmans 《Molecular systems biology》2018,14(1)
High‐content imaging using automated microscopy and computer vision allows multivariate profiling of single‐cell phenotypes. Here, we present methods for the application of the CISPR‐Cas9 system in large‐scale, image‐based, gene perturbation experiments. We show that CRISPR‐Cas9‐mediated gene perturbation can be achieved in human tissue culture cells in a timeframe that is compatible with image‐based phenotyping. We developed a pipeline to construct a large‐scale arrayed library of 2,281 sequence‐verified CRISPR‐Cas9 targeting plasmids and profiled this library for genes affecting cellular morphology and the subcellular localization of components of the nuclear pore complex (NPC). We conceived a machine‐learning method that harnesses genetic heterogeneity to score gene perturbations and identify phenotypically perturbed cells for in‐depth characterization of gene perturbation effects. This approach enables genome‐scale image‐based multivariate gene perturbation profiling using CRISPR‐Cas9. 相似文献
100.
Koen JP Verhees Nicholas AM Pansters Hoeke A Baarsma Alexander HV Remels Astrid Haegens Chiel C de Theije Annemie MWJ Schols Reinoud Gosens Ramon CJ Langen 《Respiratory research》2013,14(1):117