96 research outputs found
Biochemistry and functional aspects of human glandular kallikreins
Human urinary kallikrein was purified by gel filtration on Sephacryl S-200 and affinity chromatography on aprotinin-Sepharose, followed by ion exchange chromatography on DEAE-Sepharose. In dodecylsulfate gel electrophoresis two protein bands with molecular weights of 41,000 and 34,000 were separated. The amino acid composition and the carbohydrate content of the kallikrein preparation were determined; isoleucine was identified as the only aminoterminal amino acid. The bimolecular velocity constant for the inhibition by diisopropyl fluorophosphate was determined as 9±2 l mol–1 min–1. The hydrolysis of a number of substrates was investigated and AcPheArgOEt was found to be the most sensitive substrate for human urinary kallikrein. Using this substrate an assay method for kallikrein in human urine was developed.
It was shown by radioimmunoassay that pig pancreatic kallikrein can be absorbed in the rat intestinal tract. Furthermore, in dogs the renal excretion of glandular kallikrein from blood was demonstrated by radioimmunological methods
EPR Study of Spin Labeled Brush Polymers in Organic Solvents
Spin-labeled polylactide brush polymers were synthesized via ring-opening metathesis polymerization (ROMP), and nitroxide radicals were incorporated at three different locations of brush polymers: the end and the middle of the backbone, and the end of the side chains (periphery). Electron paramagnetic resonance (EPR) was used to quantitatively probe the macromolecular structure of brush polymers in dilute solutions. The peripheral spin-labels showed significantly higher mobility than the backbone labels, and in dimethylsulfoxide (DMSO), the backbone end labels were shown to be more mobile than the middle labels. Reduction of the nitroxide labels by a polymeric reductant revealed location-dependent reactivity of the nitroxide labels: peripheral nitroxides were much more reactive than the backbone nitroxides. In contrast, almost no difference was observed when a small molecule reductant was used. These results reveal that the dense side chains of brush polymers significantly reduce the interaction of the backbone region with external macromolecules, but allow free diffusion of small molecules
A relative entropy rate method for path space sensitivity analysis of stationary complex stochastic dynamics
We propose a new sensitivity analysis methodology for complex stochastic
dynamics based on the Relative Entropy Rate. The method becomes computationally
feasible at the stationary regime of the process and involves the calculation
of suitable observables in path space for the Relative Entropy Rate and the
corresponding Fisher Information Matrix. The stationary regime is crucial for
stochastic dynamics and here allows us to address the sensitivity analysis of
complex systems, including examples of processes with complex landscapes that
exhibit metastability, non-reversible systems from a statistical mechanics
perspective, and high-dimensional, spatially distributed models. All these
systems exhibit, typically non-gaussian stationary probability distributions,
while in the case of high-dimensionality, histograms are impossible to
construct directly. Our proposed methods bypass these challenges relying on the
direct Monte Carlo simulation of rigorously derived observables for the
Relative Entropy Rate and Fisher Information in path space rather than on the
stationary probability distribution itself. We demonstrate the capabilities of
the proposed methodology by focusing here on two classes of problems: (a)
Langevin particle systems with either reversible (gradient) or non-reversible
(non-gradient) forcing, highlighting the ability of the method to carry out
sensitivity analysis in non-equilibrium systems; and, (b) spatially extended
Kinetic Monte Carlo models, showing that the method can handle high-dimensional
problems
The CCAP knowledgebase:Linking protistan and cyanobacterial biological resources with taxonomic and molecular data
Peer reviewedPublisher PD
Effects of Ubiquinol-10 on MicroRNA-146a Expression In Vitro and In Vivo
MicroRNAs (miRs) are involved in key biological processes via suppression of gene expression at posttranscriptional levels. According to their superior functions, subtle modulation of miR expression by certain compounds or nutrients is desirable under particular conditions. Bacterial lipopolysaccharide (LPS) induces a reactive oxygen species-/NF-κB-dependent pathway which increases the expression of the anti-inflammatory miR-146a. We hypothesized that this induction could be modulated by the antioxidant ubiquinol-10. Preincubation of human monocytic THP-1 cells with ubiquinol-10 reduced the LPS-induced expression level of miR-146a to 78.9 ± 13.22%. In liver samples of mice injected with LPS, supplementation with ubiquinol-10 leads to a reduction of LPS-induced miR-146a expression to 78.12 ± 21.25%. From these consistent in vitro and in vivo data, we conclude that ubiquinol-10 may fine-tune the inflammatory response via moderate reduction of miR-146a expression
Tetraalkylammonium Cations Conduction through a Single Nanofluidic Diode: Experimental and Theoretical Studies
[EN] We describe experimentally and theoretically the concentration-dependent conduction of tetraalkylammonium
(TAA+) cations through a nanofluidic diode fabricated in a polymer membrane via
asymmetric track-etching techniques. This single-pore membrane exhibits current rectification
characteristics because of the ionized carboxylate groups on the pore surface. We use aqueous solutions
of potassium (K+
), ammonium (A+
), tetramethylammonium (TMA+
), tetraethylammonium (TEA+
), and
tetrabutylammonium (TBA+
) ions with concentrations ranging from 50 to 500 mM under acidic (pH 3.5)
and physiological (pH 6.5) conditions. Compared with the K+ and A+ ions, the TMA+
, TEA+
, and TBA+ ions
show relatively low rectified ion currents because the cation hydrophobicity increases with the alkyl
chain. At low concentrations and acidic conditions, an inversion in the current rectification
characteristics is observed, which is attributed to the adsorption of the organic cations on the pore
surfaces. The experimental results can be analyzed in terms of the Poisson-Nernst-Planck equations and
the geometrical and electrical single pore characteristics for the different ions, pH values, and salt
concentrations employed. This theoretical approach is qualitative and could be extended further to
include a self-consistent theoretical treatment of the ionic adsorption and surface charge equilibriaM. A., S. N., and W. E. acknowledge the funding from the Hessen State Ministry of Higher Education, Research and the Arts, Germany, under the LOEWE project iNAPO. P. R., J. C., and S. M. acknowledge financial support by the Spanish Ministry of Economic Affairs and Competitiveness (MAT2015-65011-P) and FEDER. The authors are also thankful to Prof. C. Trautmann, Department of Materials Research from GSI, for support with irradiation experiments.Ali, M.; Ramirez Hoyos, P.; Nasir, S.; Cervera Montesinos, J.; Mafe, S.; Ensinger, W. (2017). Tetraalkylammonium Cations Conduction through a Single Nanofluidic
Diode: Experimental and Theoretical Studies. ELECTROCHIMICA ACTA. 250:302-308. https://doi.org/10.1016/j.electacta.2017.08.078S30230825
Genetic Polymorphisms and Posttraumatic Complications
Major trauma is the leading cause of death in young adults. Despite advances in prehospital system and treatment in hospital, mortality rates have not improved significantly over the past decades. Victims of severe injuries who survive the initial hours have great risk for additional life-threatening complicaitons, including uncontrollable infection (sepsis) and multiple organ dysfunction syndrome (MODS). Single nucleotide polymorphisms (SNPs) have been shown to affect susceptibility to the course of numerous diseases. Accumulating evidence suggests that genetic backgrounds also play important roles in posttraumatic complications. Genetic polymorphisms may become powerful biomarkers for diagnosis and prognosis of trauma-induced complications. Recent advances in studies on associations between genetic polymorphisms and sepsis or MODS have led to better understanding of posttraumatic complications. Here we summarise recent findings on genetic variations in molecules of the innate immune system and other systems as well as their connection with susceptibility to posttraumatic complications
- …