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Berlin Brandenburg

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  • 2009  (7)
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  • 2009  (7)
  • 1
    Language: English
    In: The Journal of infectious diseases, 01 March 2009, Vol.199(5), pp.684-92
    Description: A gene expression study of Haemophilus ducreyi identified the hypothetical lipoprotein HD0192, renamed here "fibrinogen binder A" (FgbA), as being preferentially expressed in vivo. To test the role played by fgbA in virulence, an isogenic fgbA mutant (35000HPfgbA) was constructed using H. ducreyi 35000HP, and 6 volunteers were experimentally infected with 35000HP or 35000HPfgbA. The overall pustule-formation rate was 61.1% at parent sites and 22.2% at mutant sites (P = .019). Papules were significantly smaller at mutant sites than at parent sites (13.3 vs. 37.9 mm(2); P = .002) 24 h after inoculation. Thus, fgbA contributed significantly to the virulence of H. ducreyi in humans. In vitro experiments demonstrated that fgbA encodes a fibrinogen-binding protein; no other fibrinogen-binding proteins were identified in 35000HP. fgbA was conserved among clinical isolates of both class I and II H. ducreyi strains, supporting the finding that fgbA is important for H. ducreyi infection.
    Keywords: Bacterial Proteins -- Metabolism ; Chancroid -- Microbiology ; Fibrinogen -- Metabolism ; Haemophilus Ducreyi -- Genetics ; Lipoproteins -- Metabolism
    ISSN: 0022-1899
    E-ISSN: 15376613
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  • 2
    Language: English
    In: Southern Spaces, 01 May 2009
    Description: In this interview with Louisiana native Margaret D. Bauer, author Tim Gautreaux discusses a quarter century of his fiction writing. Resisting simplistic labels of "Cajun" and "southern," Gautreaux's storytelling reveals an intimate understanding of southern Louisiana's white, working-class people and culture. Often drawn from his own background, Gautreaux's characters are shaped by a range of experiences, from working on steamboats and fighting in world wars, to struggling in the 1980s oil bust.
    Keywords: Literary Criticism ; Regional Studies ; Social Class
    ISSN: Southern Spaces
    E-ISSN: 1551-2754
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  • 3
    Description: Indiana University-Purdue University Indianapolis (IUPUI) Flavocytochrome b558, the catalytic core of the phagocytic NADPH oxidase, mediates the transfer of electrons from NADPH to molecular oxygen to generate superoxide for host defense. Flavocytochrome b is a membrane heterodimer consisting of a large subunit gp91phox (NOX2) and a smaller subunit, p22phox. Localization of flavocytochrome b to the phagosome is essential for microbial killing, yet the subcellular distribution of flavocytochrome b in macrophages and how it is incorporated into macrophage phagosomes is not well characterized. In neutrophils, flavocytochrome b localizes primarily to specific granules that are rapidly mobilized to the phagosome upon stimulation. In contrast to neutrophils, macrophages do not contain specific granules, and trafficking of membrane proteins to the phagosome is more dynamic, involving fission and fusion events with endosomal compartments. We hypothesized that in macrophages, flavocytochrome b localizes to both plasma membrane and endosomal compartments that deliver flavocytochrome b to the phagosome. We generated fluorescently tagged versions of both p22phox and gp91phox, and rigorously verified their functionality in Chinese Hamster Ovary cells. Localization of flavocytochrome b was then examined in both RAW 264.7 murine macrophages and primary murine bone marrow derived macrophages (BMDM) in the presence and absence of interferon gamma (IFNg). We found that in “resting” macrophages, flavocytochrome b localizes primarily to the Rab11-positive endosome recycling compartment that recycles to the plasma membrane. In addition, phagocytosis assays showed flavocytochrome b is incorporated into the phagocytic cup and colocalized with Rab11 at the base of the cup, suggesting Rab11-positive endosomes may be involved in trafficking of flavocytochrome b between intracellular membranes and forming or nascent phagosomes. However, in IFNg activated macrophages, flavocytochrome b was localized predominantly in the plasma membrane, with little present in endosomal compartments. This shift in flavocytochrome b distribution occurred following sustained exposure to IFNg and correlated with increased flavocytochrome b protein expression and increased extracellular production of superoxide. Taken together, our results suggest the IFNg-induced redistribution of flavocytochrome b may be important for enhancing the production of superoxide at the cell surface and may be a potential new mechanism by which IFNg enhances antimicrobial activity in macrophages.
    Keywords: Host Defense ; Superoxide ; Superoxide
    Source: Networked Digital Library of Theses and Dissertations
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  • 4
    Language: English
    In: PLoS ONE, 2009, Vol.4(4), p.e5342
    Description: HER2-targeted therapy with the monoclonal antibody trastuzumab (Herceptin®) has improved disease-free survival for women diagnosed with HER2-positive breast cancers; however, treatment resistance and disease progression are not uncommon. Current data suggest that resistance to treatment in HER2 cancers may be a consequence of NF-κB overexpression and increased COX2-derived prostaglandin E2 (PGE 2 ). Conjugated linoleic acid (CLA) has been shown to have anti-tumor properties and to inhibit NF-κB activity and COX2. ; In this study, HER2-overexpressing SKBr3 breast cancer cells were treated with CLA. Protein expression of the HER2 receptor, nuclear NF-κB p65, and total and phosphorylated IκB were examined by western blot and immunofluorescence. PGE levels were determined by ELISA. Proliferation was measured by metabolism of 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), and apoptosis was measured by FITC-conjugated Annexin V staining and flow cytometry. ; We observed a significant decrease in HER2 protein expression on western blot following treatment with 40 and 80 µM CLA (p〈0.01 and 0.001, respectively) and loss of HER2 protein in cells using immunoflourescence that was most pronounced at 80 µM. Protein levels of nuclear NF-κB p65 were also significantly reduced at the 80 µM dose. This was accompanied by a significant decrease in PGE levels (p = 0.05). Pretreatment with CLA significantly enhanced TNFα-induced apoptosis and the anti-proliferative action of trastuzumab (p = 0.05 and 0.001, respectively). These data add to previous reports of an anti-tumor effect of CLA and suggest an effect on the HER2 oncogene that may be through CLA mediated downregulation of COX2-derived PGE.
    Keywords: Research Article ; Nutrition ; Cell Biology -- Cell Signaling ; Oncology -- Breast Cancer ; Women's Health -- Breast Cancer
    E-ISSN: 1932-6203
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  • 5
    Language: English
    In: PLoS ONE, 2009, Vol.4(5), p.e5578
    Description: Avicins, a class of electrophilic triterpenoids with pro-apoptotic, anti-inflammatory and antioxidant properties, have been shown to induce redox-dependant post-translational modification of cysteine residues to regulate protein function. Based on (a) the cross-talk that occurs between redox and phosphorylation processes, and (b) the role of Stat3 in the process of apoptosis and carcinogenesis, we chose to study the effects of avicins on the processes of phosphorylation/dephosphorylation in Stat3. Avicins dephosphorylate Stat3 in a variety of human tumor cell lines, leading to a decrease in the transcriptional activity of Stat3. The expression of Stat3-regulated proteins such as c-myc, cyclin D1, Bcl2, survivin and VEGF were reduced in response to avicin treatment. Underlying avicin-induced dephosphorylation of Stat3 was dephosphorylation of JAKs, as well as activation of protein phosphatase-1. Downregulation of both Stat3 activity and expression of Stat 3-controlled pro-survival proteins, contributes to the induction of apoptosis in avicin treated tumor cells. Based on the role of Stat3 in inflammation and wounding, and the in vivo inhibition of VEGF by avicins in a mouse skin carcinogenesis model, it is likely that avicin-induced inhibition of Stat3 activity results in the suppression of the pro-inflammatory and pro-oxidant stromal environment of tumors. Activation of PP-1, which also acts as a cellular economizer, combined with the redox regulation by avicins, can aid in redirecting metabolism from growth promoting anabolic to energy sparing pathways.
    Keywords: Research Article ; Cell Biology ; Oncology ; Cell Biology -- Cell Signaling
    E-ISSN: 1932-6203
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  • 6
    Language: English
    In: PLoS ONE, 2009, Vol.4(12), p.e8115
    Description: There has been much interest in targeting intracellular redox pathways as a therapeutic approach for cancer. Given recent data to suggest that the redox status of extracellular protein thiol groups (i.e. exofacial thiols) effects cell behavior, we hypothesized that redox active anti-cancer agents would modulate exofacial protein thiols. ; To test this hypothesis, we used the sesquiterpene lactone parthenolide, a known anti-cancer agent. Using flow cytometry, and western blotting to label free thiols with Alexa Fluor 633 C maleimide dye and N-(biotinoyl)-N-(iodoacetyl) ethylendiamine (BIAM), respectively, we show that parthenolide decreases the level of free exofacial thiols on Granta mantle lymphoma cells. In addition, we used immuno-precipitation techniques to identify the central redox regulator thioredoxin, as one of the surface protein thiol targets modified by parthenolide. To examine the functional role of parthenolide induced surface protein thiol modification, we pretreated Granta cells with cell impermeable glutathione (GSH), prior to exposure to parthenolide, and showed that GSH pretreatment; (a) inhibited the interaction of parthenolide with exofacial thiols; (b) inhibited parthenolide mediated activation of JNK and inhibition of NFκB, two well established mechanisms of parthenolide activity and; (c) blocked the cytotoxic activity of parthenolide. That GSH had no effect on the parthenolide induced generation of intracellular reactive oxygen species supports the fact that GSH had no effect on intracellular redox. Together these data support the likelihood that GSH inhibits the effect of parthenolide on JNK, NFκB and cell death through its direct inhibition of parthenolide's modulation of exofacial thiols. ; Based on these data, we postulate that one component of parthenolide's anti-lymphoma activity derives from its ability to modify the redox state of critical exofacial thiols. Further, we propose that cancer cell exofacial thiols may be important and novel targets for therapy.
    Keywords: Research Article ; Biochemistry ; Hematology ; Hematology -- Acute Lymphoblastic Leukemia ; Hematology -- Acute Myeloid Leukemia ; Oncology -- Myelomas And Lymphoproliferative Diseases ; Oncology -- Myeloproliferative Disorders, Including Chronic Myeloid Leukemia
    E-ISSN: 1932-6203
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  • 7
    In: American Mineralogist, 2009, Vol.94(2), pp.359-366
    Description: Garnet solid solutions have been synthesized across the skiagite-Fe-knorringite (Fe 3 2+ Fe 2 3+ Si 3 O 12 - Fe 3 Cr 2 Si 3 O 12 ) binary join. Such compositions reflect a simple Cr-Fe 3+ exchange on the octahedral sites, with Fe 2+ occupying the adjacent dodecahedral sites. Solid solution is complete across the join and the correct stoichiometry was verified by Mössbauer spectroscopy. A symmetric fit to the molar volume data yields 119.77(2) cm 3 /mol [unit-cell parameter ao =11.6736(7) Å] for the Fe-knorringite end-member and a small negative excess volume, W v = -0.76(15) cm 3 /mol. Combining this result with literature data reveals that binary joins involving octahedral site substitutions exhibit significantly different behavior than those where substitution occurs on the dodecahedral sites. In the former case, WV is usually negative, whereas the latter joins have positive deviations from ideal behavior. Therefore, we conclude that the garnet structure responds in a fundamentally different way when accommodating different cations on the dodecahedral or octahedral sites. Mössbauer spectra of skiagite-Fe-knorringite garnets do not exhibit any significant asymmetry in the [8] Fe 2+ doublet. Fe 3+ /ΣFe values determined at room temperature and 80 K confirm the general applicability of the recoil-free fraction correction factors reported by Woodland and Ross (1994) for mixed-valence garnets. Coexisting spinels in some samples are either binary Fe 3 O 4 -Fe 2 SiO 4 or Fe 3 O 4 -FeCr 2 O 4 solid solutions. Very little mutual solubility is apparent suggesting a significant solvus may exist between the silicate and Cr-bearing spinel series.
    Keywords: Fe-Knorringite ; Fe-Cr Garnet ; Skiagite ; Molar Volume ; Mössbauer Spectroscopy ; Excess Thermodynamic Properties ; Fe-Cr Spinel
    ISSN: 0003-004X
    E-ISSN: 1945-3027
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