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  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 13 January 2015, Vol.112(2), pp.E127-36
    Description: Bactofilins are a widespread class of bacterial filament-forming proteins, which serve as cytoskeletal scaffolds in various cellular pathways. They are characterized by a conserved architecture, featuring a central conserved domain (DUF583) that is flanked by variable terminal regions. Here, we present a detailed investigation of bactofilin filaments from Caulobacter crescentus by high-resolution solid-state NMR spectroscopy. De novo sequential resonance assignments were obtained for residues Ala39 to Phe137, spanning the conserved DUF583 domain. Analysis of the secondary chemical shifts shows that this core region adopts predominantly β-sheet secondary structure. Mutational studies of conserved hydrophobic residues located in the identified β-strand segments suggest that bactofilin folding and polymerization is mediated by an extensive and redundant network of hydrophobic interactions, consistent with the high intrinsic stability of bactofilin polymers. Transmission electron microscopy revealed a propensity of bactofilin to form filament bundles as well as sheet-like, 2D crystalline assemblies, which may represent the supramolecular arrangement of bactofilin in the native context. Based on the diffraction pattern of these 2D crystalline assemblies, scanning transmission electron microscopy measurements of the mass per length of BacA filaments, and the distribution of β-strand segments identified by solid-state NMR, we propose that the DUF583 domain adopts a β-helical architecture, in which 18 β-strand segments are arranged in six consecutive windings of a β-helix.
    Keywords: Cytoskeleton ; Filaments ; Protein Structure ; Solid-State NMR ; Bacterial Proteins -- Chemistry ; Caulobacter Crescentus -- Chemistry ; Cytoskeleton -- Chemistry
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 2
    In: PLoS ONE, 2017, Vol.12(1)
    Description: Background Phytoestrogens such as genistein, the most prominent isoflavone from soy, show concentration-dependent anti-estrogenic or estrogenic effects. High genistein concentrations (〉10 μM) also promote proliferation of bone cancer cells in vitro . On the other hand, the most active component of the vitamin D family, calcitriol, has been shown to be tumor protective in vitro and in vivo . The purpose of this study was to examine a putative synergism of genistein and calcitriol in two osteosarcoma cell lines MG-63 (early osteoblast), Saos-2 (mature osteoblast) and primary osteoblasts. Methods Thus, an initial screening based on cell cycle phase alterations, estrogen (ER) and vitamin D receptor (VDR) expression, live cell metabolic monitoring, and metabolomics were performed. Results Exposure to the combination of 100 μM genistein and 10 nM calcitriol reduced the number of proliferative cells to control levels, increased ERß and VDR expression, and reduced extracellular acidification (40%) as well as respiratory activity (70%), primarily in MG-63 cells. In order to identify the underlying cellular mechanisms in the MG-63 cell line, metabolic profiling via GC/MS technology was conducted. Combined treatment significantly influenced lipids and amino acids preferably, whereas metabolites of the energy metabolism were not altered. The comparative analysis of the log2-ratios revealed that after combined treatment only the metabolite ethanolamine was highly up-regulated. This is the result: a strong overexpression (350%) of the enzyme sphingosine-1-phosphate lyase (SGPL1), which irreversibly degrades sphingosine-1-phosphate (S1P), thereby, generating ethanolamine. S1P production and secretion is associated with an increased capability of migration and invasion of cancer cells. Conclusion From these results can be concluded that the tumor promoting effect of high concentrations of genistein in immature osteosarcoma cells is reduced by the co-administration of calcitriol, primarily by the breakdown of S1P. It should be tested whether this anti-metastatic pathway can be stimulated by combined treatment also in metastatic xenograft mice models.
    Keywords: Research Article ; Biology And Life Sciences ; Biology And Life Sciences ; Biology And Life Sciences ; Biology And Life Sciences ; Physical Sciences ; Physical Sciences ; Research And Analysis Methods ; Research And Analysis Methods ; Biology And Life Sciences ; Biology And Life Sciences ; Medicine And Health Sciences
    E-ISSN: 1932-6203
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  • 3
    Language: English
    In: Applied and environmental microbiology, January 2015, Vol.81(2), pp.736-44
    Description: The alphaproteobacterium Hyphomonas neptunium proliferates by a unique budding mechanism in which daughter cells emerge from the end of a stalk-like extension emanating from the mother cell body. Studies of this species so far have been hampered by the lack of a genetic system and of molecular tools allowing the regulated expression of target genes. Based on microarray analyses, this work identifies two H. neptunium promoters that are activated specifically by copper and zinc. Functional analyses show that they have low basal activity and a high dynamic range, meeting the requirements for use as a multipurpose expression system. To facilitate their application, the two promoters were incorporated into a set of integrative plasmids, featuring a choice of two different selection markers and various fluorescent protein genes. These constructs enable the straightforward generation and heavy metal-inducible synthesis of fluorescent protein fusions in H. neptunium, thereby opening the door to an in-depth analysis of polar growth and development in this species.
    Keywords: Alphaproteobacteria -- Genetics ; Genetics, Microbial -- Methods ; Molecular Biology -- Methods
    ISSN: 00992240
    E-ISSN: 1098-5336
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  • 4
    Language: English
    In: PLoS ONE, 01 January 2018, Vol.13(5), p.e0196854
    Description: The bioactive lipid sphingosine-1-phosphate (S1P) is a main regulator of cell survival, proliferation, motility, and platelet aggregation, and it is essential for angiogenesis and lymphocyte trafficking. In that S1P acts as a second messenger intra- and extracellularly, it might promote cancer progression. The main cause is found in the high S1P concentration in the blood, which encourage cancer cells to migrate through the endothelial barrier into the blood vessels. The irreversible degradation of S1P is solely caused by the sphingosine-1-phosphate lyase (SGPL1). SGPL1 overexpression reduces cancer cell migration and therefore silences the endogenous S1P siren, which promotes cancer cell attraction-the main reason for metastasis. Since our previous metabolomics studies revealed an increased SGPL1 activity in association with successful breast cancer cell treatment in vitro, we further investigated expression and localization of SGPL1. Expression analyses confirmed a very low SGPL1 expression in all breast cancer samples, regardless of their subtype. Additionally, we were able to prove a novel SGPL expression in the cytoplasm membrane of non-tumorigenic breast cells by fusing three independent methods. The general SGPL1 downregulation and the loss of the plasma membrane expression resulted in S1P dependent stimulation of migration in the breast cancer cell lines MCF-7 and BT-20. Not only S1P stimulated migration could be repressed by overexpressing the natural SGPL1 variant not but also more general migratory activity was significantly reduced. Here, for the first time, we report on the SGPL1 plasma membrane location in human, non-malignant breast epithelial cell lines silencing the extracellular S1P siren in vitro, and thereby regulating pivotal cellular functions. Loss of this plasma membrane distribution as well as low SGPL1 expression levels could be a potential prognostic marker and a viable target for therapy. Therefore, the precise role of SGPL1 for cancer treatment should be evaluated.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 5
    In: EMBO Journal, 20 January 2010, Vol.29(2), pp.327-339
    Description: The cytoskeleton has a key function in the temporal and spatial organization of both prokaryotic and eukaryotic cells. Here, we report the identification of a new class of polymer‐forming proteins, termed bactofilins, that are widely conserved among bacteria. In , two bactofilin paralogues cooperate to form a sheet‐like structure lining the cytoplasmic membrane in proximity of the stalked cell pole. These assemblies mediate polar localization of a peptidoglycan synthase involved in stalk morphogenesis, thus complementing the function of the actin‐like cytoskeleton and the cell division machinery in the regulation of cell wall biogenesis. In other bacteria, bactofilins can establish rod‐shaped filaments or associate with the cell division apparatus, indicating considerable structural and functional flexibility. Bactofilins polymerize spontaneously in the absence of additional cofactors , forming stable ribbon‐ or rod‐like filament bundles. Our results suggest that these structures have evolved as an alternative to intermediate filaments, serving as versatile molecular scaffolds in a variety of cellular pathways.
    Keywords: Cytoskeleton ; Myxococcus Xanthus ; Penicillin‐Binding Protein ; Peptidoglycan ; Stalk
    ISSN: 0261-4189
    E-ISSN: 1460-2075
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  • 6
    Language: German
    In: s u b u r b a n : zeitschrift für kritische stadtforschung, 01 November 2017, Vol.5(3), pp.137-146
    Description: Universität und Stadt als Orte der gesellschaftlichen Reproduktion sind durch Hierarchien, Herausforderungen und Zwänge gekennzeichnet, die einer feministisch solidarischen Praxis in vielerlei Hinsicht (diametral) entgegenstehen. Entlang der Diskussionen von Beispielen aktueller Reproduktionsverhältnisse und Bedingungen von Care-Arbeit, sowohl in der Akademie als auch in der Stadt, wollen wir mit diesem Beitrag Erfahrungen und Möglichkeiten besprechen, die während des Vernetzungstreffens „Feministische Geographien“ im April 2017 in Hamburg gemeinsam erprobt wurden.
    Keywords: Solidarische Wissensproduktion ; Feministische Geographien ; Krise Der Reproduktion ; Sociology & Social History
    E-ISSN: 2197-2567
    Source: Directory of Open Access Journals (DOAJ)
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  • 7
    Language: English
    In: 2014, Vol.8(12), p.e3347
    Description: Despite major attempts to prevent cholera transmission, millions of people worldwide still must address this devastating disease. Cholera research has so far mainly focused on the causative agent, the bacterium Vibrio cholerae , or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT), whereby water and electrolytes are replenished. Commonly distributed oral rehydration salts also contain glucose. Here, we analyzed the effects of glucose and alternative carbon sources on the production of virulence determinants in the causative agent of cholera, the bacterium Vibrio cholerae during in vitro experimentation. We demonstrate that virulence gene expression and the production of cholera toxin are enhanced in the presence of glucose or similarly transported sugars in a ToxR-, TcpP- and ToxT-dependent manner. The virulence genes were significantly less expressed if alternative non-PTS carbon sources, including rice-based starch, were utilized. Notably, even though glucose-based ORT is commonly used, field studies indicated that rice-based ORT performs better. We therefore used a spatially explicit epidemiological model to demonstrate that the better performing rice-based ORT could have a significant impact on epidemic progression based on the recent outbreak of cholera in Haiti. Our results strongly support a change of carbon source for the treatment of cholera, especially in epidemic settings. ; Cholera research has so far mainly focused on the causative agent, the bacterium , or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT). ORT aims at rehydrating patients through the provision of water and oral rehydration salts; the latter being composed of electrolytes as well as glucose as a carbon source. Although glucose-based ORS is commonly used to treat diarrheal diseases and is recommended by the WHO, field studies on cholera indicated that rice-based ORT performs better than glucose-based ORT. Here, we investigated the impact that glucose, starch, or other carbon sources exert on . We demonstrated that glucose leads to an increased expression of the major virulence genes in the pathogen and, accordingly, to an enhanced production of cholera toxin during experimentation. Because the cholera toxin is primarily responsible for the severe symptoms that are associated with the disease, our study highlights the negative effects of glucose-based ORT. Next, we used a spatially explicit epidemiological model to demonstrate that the better performing rice-based ORS could have a significant impact on epidemic progression based on the recent outbreak of cholera in Haiti.
    Keywords: Research Article ; Biology And Life Sciences ; Medicine And Health Sciences
    ISSN: 19352727
    E-ISSN: 1935-2735
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  • 8
    Language: English
    In: BMC complementary and alternative medicine, 09 September 2014, Vol.14, pp.334
    Description: Jatropha curcas (JCP1), Pyrenacantha staudtii (PS), Picralima nitida (ZI) and Jatropha gossypifolia (JCP2) are plants used in the African folklore for the treatment of various cancers. This study investigated the in vitro anticancer effects of the ethanol extracts against human epithelial MCF-7 breast cancer cells in a dose-dependent manner (1-50 μg/ml) by using cell cycle analysis, viability assay, annexin V/PI staining, TUNEL method and expression determination of apoptotic and adhesion relevant proteins. Adhesion processes were monitored by detachment via flow cytometry, β1-integrin expression and formation of the actin cytoskeleton. The three extracts, termed PS, JCP1 and JCP2 at a concentration of 10 μg/ml induced cell death in MCF-7 breast cancer cells verified by high amounts of PI-positive cells in the cell cycle analysis, Annexin V/PI staining and DNA fragmentation measurements. In parallel cell detachment was accompanied by decreased β1- integrin expression and phosphorylation of the focal adhesion kinase at Tyr397. ZI extract was the exception by the increasing β1-integrin expression and strengthening the cortical actin cytoskeleton. However, all four plant extracts mediated strong anti-cancer properties with IC50 values between 23-38 μg/ml. PS, JCP1 and JCP2 were found to be very active against MCF-7 cells by inducing anoikis and therefore possessing vast potential as medicinal drugs especially in estrogen receptor positive breast cancer treatment. ZI mediated their anti-cancer action by different signaling mechanisms which should be analyzed in future studies. Our results further supported the idea that medicinal plants can be promising sources of putative anticancer agents.
    Keywords: Apoptosis -- Drug Effects ; Breast Neoplasms -- Pathology ; Cell Adhesion -- Drug Effects ; Medicine, African Traditional -- Methods ; Plant Extracts -- Pharmacology
    E-ISSN: 1472-6882
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  • 9
    Language: German
    Description: Universität und Stadt als Orte der gesellschaftlichen Reproduktion sind durch Hierarchien, Herausforderungen und Zwänge gekennzeichnet, die einer feministisch solidarischen Praxis in vielerlei Hinsicht (diametral) entgegenstehen. Entlang der Diskussionen von Beispielen aktueller Reproduktionsverhältnisse und Bedingungen von Care-Arbeit, sowohl in der Akademie als auch in der Stadt, wollen wir mit diesem Beitrag Erfahrungen und Möglichkeiten besprechen, die während des Vernetzungstreffens „Feministische Geographien“ im April 2017 in Hamburg gemeinsam erprobt wurden....
    Keywords: Universität ; Wissenschaft ; Feministische Kritik ; Sorgearbeit ; Widerstand ; Lehre ; Ausbeutung ; Alltag ; Feminismus ; Sozialwissenschaften
    ISSN: 2197-2567
    Source: DataCite
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  • 10
    Language: English
    In: Open Forum Infectious Diseases, 12/01/2016, Vol.3(suppl_1)
    Keywords: Medicine;
    ISSN: Open Forum Infectious Diseases
    E-ISSN: 2328-8957
    Source: Oxford University Press (via CrossRef)
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