University of Marburg

About: University of Marburg is a education organization based out in Marburg, Germany. It is known for research contribution in the topics: Population & Virus. The organization has 23195 authors who have published 42907 publications receiving 1506069 citations. The organization is also known as: Philipps University of Marburg & Philipps-Universität.

Periodic-orbit quantization of chaotic systems.

Abstract: We demonstrate the utility of the periodic-orbit description of chaotic motion by computing from a few periodic orbits highly accurate estimates of a large number of quantum resonances for the classically chaotic three-disk scattering problem. The symmetry decompositions of the eigenspectra are the same for the classical and the quantum problem, and good agreement between the periodic-orbit estimates and the exact quantum poles is observed

Small cationic antimicrobial peptides delocalize peripheral membrane proteins

Abstract: Short antimicrobial peptides rich in arginine (R) and tryptophan (W) interact with membranes. To learn how this interaction leads to bacterial death, we characterized the effects of the minimal pharmacophore RWRWRW-NH2. A ruthenium-substituted derivative of this peptide localized to the membrane in vivo, and the peptide also integrated readily into mixed phospholipid bilayers that resemble Gram-positive membranes. Proteome and Western blot analyses showed that integration of the peptide caused delocalization of peripheral membrane proteins essential for respiration and cell-wall biosynthesis, limiting cellular energy and undermining cell-wall integrity. This delocalization phenomenon also was observed with the cyclic peptide gramicidin S, indicating the generality of the mechanism. Exogenous glutamate increases tolerance to the peptide, indicating that osmotic destabilization also contributes to antibacterial efficacy. Bacillus subtilis responds to peptide stress by releasing osmoprotective amino acids, in part via mechanosensitive channels. This response is triggered by membrane-targeting bacteriolytic peptides of different structural classes as well as by hypoosmotic conditions.

Reduced levels of amyloid β-peptide antibody in Alzheimer disease

Abstract: Objective: To investigate whether it was possible to detect the presence and different levels of naturally occurring anti-β-amyloid (Aβ) antibodies in the CSF of patients with AD and age-matched controls by employing a sensitive ELISA. Background: Immunization with preaggregated amyloid β-peptide (Aβ 1–42 ) and administration of antibodies against Aβ into amyloid precursor protein APP V717F – transgenic mice (an animal model of AD) have recently been reported to dramatically reduce amyloid plaque deposition, neuritic dystrophy, and astrogliosis, most likely by enhancing Aβ clearance from brain. Methods: A sensitive ELISA was performed to detect levels of naturally occurring anti-Aβ antibodies in the CSF of patients with AD and age-matched controls. Additionally, an immunoprecipitation assay was performed to confirm that naturally occurring anti-Aβ antibodies also exist in the human blood. Result: Naturally occurring antibodies directed against Aβ were found in the CSF and plasma of patients with AD and healthy control subjects. Moreover, CSF anti-Aβ antibody titers are significantly lower in patients with AD compared with healthy control subjects. Conclusion: Naturally occurring antibodies directed against Aβ exist in human CSF and plasma. The CSF anti-Aβ antibody titers may be helpful in better understanding the effects of future immunologic therapies for AD.