184 results match your criteria: "University Bayreuth[Affiliation]"

The form and exact function of the blood vessel network in some human organs, like spleen and bone marrow, are still open research questions in medicine. In this paper, we propose a method to register the immunohistological stainings of serial sections of spleen and bone marrow specimens to enable the visualization and visual inspection of blood vessels. As these vary much in caliber, from mesoscopic (millimeter-range) to microscopic (few micrometers, comparable to a single erythrocyte), we need to utilize a multi-resolution approach.

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An inter-laboratory comparison of gaseous and liquid fumigation based methods for measuring microbial phosphorus (Pmic) in forest soils with differing P stocks.

J Microbiol Methods

September 2016

Research Unit Environmental Genomics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.

In an inter-laboratory trial, gaseous ("CFE") and liquid fumigation ("Resin") based methods for measuring microbial phosphorus (Pmic) were compared, based on the analysis of soil samples from five forests, which differ in their P stocks. Both methods reliably detected the same Pmic gradient in the different soils. However, when the individual recovery rates of spiked P were taken into account, the "CFE" based methods consistently generated higher Pmic values (factor 2) compared to the "Resin" based approaches.

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A rhodium(i) and a ruthenium(ii) complex with a caffeine derived N-heterocyclic carbene (NHC) ligand were biologically investigated as organometallic conjugates consisting of a metal center and a naturally occurring moiety. While the ruthenium(ii) complex was largely inactive, the rhodium(i) NHC complex displayed selective cytotoxicity and significant anti-metastatic and in vivo anti-vascular activities and acted as both a mammalian and an E. coli thioredoxin reductase inhibitor.

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Total Synthesis of Aurantoside G, an N-β-Glycosylated 3-Oligoenoyltetramic Acid from Theonella swinhoei.

Angew Chem Int Ed Engl

August 2016

Organic Chemistry Laboratory, University Bayreuth, Universitaetsstr. 30, 95447, Bayreuth, Germany.

The first synthesis of a natural N-glycosylated 3-acyltetramic acid is reported. Aurantoside G (1 g), a deep-red metabolite of the marine sponge Theonella swinhoei, is highly delicate in the pure state. It features a chlorinated dodecapentaenoyl side chain at an l-asparagine-derived tetramic acid, the ring nitrogen atom of which is linked to a β-configured d-xylose.

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Plant diversity and functional groups affect Si and Ca pools in aboveground biomass of grassland systems.

Oecologia

September 2016

Department of Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85350, Freising, Germany.

Plant diversity is an important driver of nitrogen and phosphorus stocks in aboveground plant biomass of grassland ecosystems, but plant diversity effects on other elements also important for plant growth are less understood. We tested whether plant species richness, functional group richness or the presence/absence of particular plant functional groups influences the Si and Ca concentrations (mmol g(-1)) and stocks (mmol m(-2)) in aboveground plant biomass in a large grassland biodiversity experiment (Jena Experiment). In the experiment including 60 temperate grassland species, plant diversity was manipulated as sown species richness (1, 2, 4, 8, 16) and richness and identity of plant functional groups (1-4; grasses, small herbs, tall herbs, legumes).

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STEM EDX Nitrogen Mapping of Nanoinclusions in Milky Diamonds from Juina, Brazil, Using a Windowless Silicon Drift Detector System.

Anal Chem

June 2016

Department 3.3, Chemistry and Physics of Earth Materials, GeoForschungsZentrum Potsdam , 14473 Potsdam, Germany.

Energy-dispersive X-ray spectroscopy (EDX) performed using scanning transmission electron microscopy (STEM) in combination with a windowless detector setup allows high-resolution imaging and chemical composition mapping even of light elements present in low concentrations. The used TEM-system combines a field emission electron source with four silicon drift detectors allowing for high detection sensitivity. We used this enhanced system to investigate 20 to 200 nm sized inclusions in milky diamonds from Rio Soriso, Juina area, Brazil.

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5-(1-Methyl-4-phenyl-imidazol-5-yl)indoles 5 were prepared and tested as analogs of the natural vascular-disrupting agent combretastatin A-4 (CA-4). The 3-bromo-4,5-dimethoxyphenyl derivative 5c was far more active than CA-4 with low nanomolar IC50 concentrations against multidrug-resistant KB-V1/Vbl cervix and MCF-7/Topo mamma carcinoma cells, and also against CA-4-resistant HT-29 colon carcinoma cells. While not interfering markedly with the polymerization of tubulin in vitro, indole 5c completely disrupted the microtubule cytoskeleton of cancer cells at low concentrations.

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Four stereoisomers of the spider-pathogenic fungus metabolite torrubiellone D were synthesized for the first time in 10% overall yield starting from L-tyrosine or D-tyrosine. The 3-decatrienoyl side chain was assembled and attached via (E)-selective HWE and Wittig olefinations. Their antibiotic activities against drug-susceptible Escherichia coli strains differed considerably.

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Wet-Laid Meets Electrospinning: Nonwovens for Filtration Applications from Short Electrospun Polymer Nanofiber Dispersions.

Macromol Rapid Commun

February 2016

Macromolecular Chemistry II, Bayreuth Center for Colloids and Interfaces, University Bayreuth, Universitätsstraße 30, Bayreuth, 95440, Germany.

Dispersions of short electrospun fibers are utilized for the preparation of nanofiber nonwovens with different weight area on filter substrates. The aerosol filtration efficiencies of suspension-borne nanofiber nonwovens are compared to nanofiber nonwovens prepared directly by electrospinning with similar weight area. The filtration efficiencies are found to be similar for both types of nonwovens.

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The response of Arabidopsis thaliana to low-oxygen stress (hypoxia), such as during shoot submergence or root waterlogging, includes increasing the levels of ∼50 hypoxia-responsive gene transcripts, many of which encode enzymes associated with anaerobic metabolism. Upregulation of over half of these mRNAs involves stabilization of five group VII ethylene response factor (ERF-VII) transcription factors, which are routinely degraded via the N-end rule pathway of proteolysis in an oxygen- and nitric oxide-dependent manner. Despite their importance, neither the quantitative contribution of individual ERF-VIIs nor the cis-regulatory elements they govern are well understood.

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The new aluminium based metal-organic framework [Al(OH)(O2C-C4H8-CO2)]·H2O denoted as Al-MIL-53-ADP-lp (lp stands for large pore) was synthesised under solvothermal conditions. This solid is an analogue of the archetypical aluminium terephthalate Al-MIL-53 based on the aliphatic single-chain linker molecule adipic acid (H2ADP, hexanedioic acid). In contrast to its aromatic counterparts, Al-MIL-53-ADP exhibits a structural breathing behaviour solely upon dehydration/rehydration.

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Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events.

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Biology and management of sugarcane yellow leaf virus: an historical overview.

Arch Virol

December 2015

Everglades Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 3200 East Palm Beach Road, Belle Glade, FL, 33430-4702, USA.

Sugarcane yellow leaf virus (SCYLV) is one of the most widespread viruses causing disease in sugarcane worldwide. The virus has been responsible for drastic economic losses in most sugarcane-growing regions and remains a major concern for sugarcane breeders. Infection with SCYLV results in intense yellowing of the midrib, which extends to the leaf blade, followed by tissue necrosis from the leaf tip towards the leaf base.

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Dopamine is a key regulator in the signalling pathway underlying predator-induced defences in Daphnia.

Proc Biol Sci

October 2015

Department of Animal Ecology, Evolution and Biodiversity, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany.

The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g.

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The Pressure-Induced Polymorphic Transformations in Fluconazole.

J Pharm Sci

December 2015

Frank Laboratory of Neutron Physics, JINR, Dubna, Moscow Region 141980, Russia.

The structural properties and Raman spectra of fluconazole have been studied by means of X-ray diffraction and Raman spectroscopy at pressures up to 2.5 and 5.5 GPa, respectively.

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Purpose: The 4,5-diarylimidazole brimamin is an analog of the natural vascular-disrupting agent combretastatin A-4 (CA-4) with improved water solubility, tolerance by animals and efficacy in multidrug-resistant tumors. Here, we aimed at identifying the major mechanisms underlying the in vitro and in vivo actions of brimamin on endothelial and carcinoma cells, including vascularization.

Methods: The contribution of specific signaling kinases to the effects of brimamin on cytoskeleton organization and the viability and differentiation of endothelial cells was assessed by MTT and tube formation assays in the presence or absence of specific kinase inhibitors.

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Innovative methods in soil phosphorus research: A review.

J Plant Nutr Soil Sci (1999)

February 2015

Soil Science, Faculty for Agricultural and Environmental Sciences, University of Rostock Justus-von-Liebig Weg 6, 18051 Rostock, Germany.

Article Synopsis
  • Phosphorus is crucial for life on Earth, and growing concerns about its future supply have led to increased research on soil phosphorus methods in the last decade.
  • This review highlights advanced techniques used in soil phosphorus research, including various spectroscopic and spectrometric methods like NMR, IR, and Q-TOF MS/MS.
  • It also discusses methods for studying soil phosphorus reactions and offers guidance on selecting appropriate methods or combinations based on their experimental setups, strengths, and limitations.
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Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions.

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Influence of W, Mo and Ti trace elements on the phase separation in Al8Co17Cr17Cu8Fe17Ni33 based high entropy alloy.

Ultramicroscopy

December 2015

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.

Compositionally complex alloys, also called high entropy alloys, have been investigated for over a decade in view of different applications, but so far only a small number of alloys can be considered as presenting good enough properties for industrial application. The most common family of elements is Al-Co-Cr-Cu-Fe-Ni. The equiatomic alloy having 5 phases and being too brittle, the composition has been modified in order to improve the mechanical properties.

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Strategies of Gammarus pulex L. to cope with arsenic--Results from speciation analyses by IC-ICP-MS and XAS micro-mapping.

Sci Total Environ

October 2015

Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.

The invertebrate shredder Gammarus pulex L. is a key species for aquatic carbon turnover via litter decomposition and can thrive in high-arsenic (As) environments. To understand their strategies for coping with increased As concentrations while fulfilling their ecosystem functions, we analyzed the As concentration and speciation in their aquatic habitat and in leaves with heterotrophic biofilms as their natural food source.

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While magnetosome biosynthesis within the magnetotactic Proteobacteria is increasingly well understood, much less is known about the genetic control within deep-branching phyla, which have a unique ultrastructure and biosynthesize up to several hundreds of bullet-shaped magnetite magnetosomes arranged in multiple bundles of chains, but have no cultured representatives. Recent metagenomic analysis identified magnetosome genes in the genus 'Candidatus Magnetobacterium' homologous to those in Proteobacteria. However, metagenomic analysis has been limited to highly abundant members of the community, and therefore only little is known about the magnetosome biosynthesis, ecophysiology and metabolic capacity in deep-branching MTB.

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Introduction: Combretastatin A-4 (CA-4) is a natural cis-stilbene which interferes with the cellular tubulin dynamics and which selectively destroys tumour blood vessels. Its pharmacological shortcomings such as insufficient chemical stability, water solubility, and cytotoxicity can be remedied by employing its imidazole derivatives.

Methods: We studied 11 halogenated imidazole derivatives of CA-4 for their effects on the microtubule and actin cytoskeletons of cancer and endothelial cells and on the propensity of these cells to migrate across tissue barriers or to form blood vessel-like tubular structures.

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The greening after extended darkness1 is an N-end rule pathway mutant with high tolerance to submergence and starvation.

Plant Physiol

April 2015

Plant Physiology, University Bayreuth, 95440 Bayreuth, Germany (W.R., J.T.M., A.M.);Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University, 6525 AJ Nijmegen, The Netherlands (E.J.W.V.); andPlant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584 CH Utrecht, The Netherlands (R.S., L.A.C.J.V.)

Plants respond to reductions in internal oxygen concentrations with adaptive mechanisms (for example, modifications of metabolism to cope with reduced supply of ATP). These responses are, at the transcriptional level, mediated by the group VII Ethylene Response Factor transcription factors, which have stability that is regulated by the N-end rule pathway of protein degradation. N-end rule pathway mutants are characterized by a constitutive expression of hypoxia response genes and abscisic acid hypersensitivity.

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Purpose: New (4-aryl-1-methylimidazol-5-yl)cinnamoylhydroxamic acids were prepared as potential dual mode anticancer agents combining the antivascular effect of the 4,5-diarylimidazole moiety and the histone deacetylases (HDAC) inhibition by the cinnamoyl hydroxamate.

Methods: Their antiproliferative activity against a panel of primary cells and cancer cell lines was determined by MTT assays and their apoptosis induction by caspase-3 activation. Their ability to reduce the activity of HDAC was measured by enzymatic assays and Western blot analyses of cellular HDAC substrates.

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