14 research outputs found
Modeling oscillatory Microtubule--Polymerization
Polymerization of microtubules is ubiquitous in biological cells and under
certain conditions it becomes oscillatory in time. Here simple reaction models
are analyzed that capture such oscillations as well as the length distribution
of microtubules. We assume reaction conditions that are stationary over many
oscillation periods, and it is a Hopf bifurcation that leads to a persistent
oscillatory microtubule polymerization in these models. Analytical expressions
are derived for the threshold of the bifurcation and the oscillation frequency
in terms of reaction rates as well as typical trends of their parameter
dependence are presented. Both, a catastrophe rate that depends on the density
of {\it guanosine triphosphate} (GTP) liganded tubulin dimers and a delay
reaction, such as the depolymerization of shrinking microtubules or the decay
of oligomers, support oscillations. For a tubulin dimer concentration below the
threshold oscillatory microtubule polymerization occurs transiently on the
route to a stationary state, as shown by numerical solutions of the model
equations. Close to threshold a so--called amplitude equation is derived and it
is shown that the bifurcation to microtubule oscillations is supercritical.Comment: 21 pages and 12 figure
Soluble forms of tau are toxic in Alzheimer's disease
Accumulation of neurofibrillary tangles (NFT), intracellular inclusions of fibrillar forms of tau, is a hallmark of Alzheimer Disease. NFT have been considered causative of neuronal death, however, recent evidence challenges this idea. Other species of tau, such as soluble misfolded, hyperphosphorylated, and mislocalized forms, are now being implicated as toxic. Here we review the data supporting soluble tau as toxic to neurons and synapses in the brain and the implications of these data for development of therapeutic strategies for Alzheimerâs disease and other tauopathies
Novel antibody against low-n oligomers of tau protein promotes clearance of tau in cells via lysosomes.
Introduction: Tau, a natively unfolded soluble protein, forms abnormal oligomers and insoluble filaments in several neurodegenerative diseases, including Alzheimer disease (AD). Tau-induced toxicity is mainly due to oligomers rather than monomers or fibrils. Methods: We have developed monoclonal antibodies against purified low-n tau oligomers of the tau repeat domain as a tool to neutralize tau aggregation and toxicity. In vitro aggregation inhibition was tested by thioflavin S, dynamic light scattering (DLS), and atomic force microscopy (AFM). Using a split-luciferase complementation assay and fluorescence-activated cell sorting (FACS), the inhibition of aggregation was analyzed in an N2a cell model of tauopathy. Results: Antibodies inhibited tau aggregation in vitro up to ~90% by blocking tau at an oligomeric state. Some antibodies were able to block tau dimerization/oligomerization in cells, as measured by a split-luciferase complementation assay. Antibodies applied extracellularly were internalized and led to sequestration of tau into lysosomes for degradation. Discussion: Novel low-n tau oligomer specific monoclonal antibody inhibits Tau oligomerization in cells and promotes toxic tau clearance
Roentgenkristallographie von Tubulin
SIGLEAvailable from TIB Hannover: DtF QN1(69,55) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman
Observation of subcellular structures of neurons by an illumination mode near-field optical microscope under an optical feedback control
Observation of subcellular structures of neurons by an illumination mode near-field optical microscope under an optical feedback control
Közösségfejlesztés a Magyarorszågi Baptista Egyhåzban
Szakdolgozatom tĂ©mĂĄjakĂ©nt a Baptista EgyhĂĄzban folyĂł közössĂ©gfejlesztĂ©s elemzĂ©sĂ©t vĂĄlasztottam. A közössĂ©gfejlesztĂ©s napjainkban a szociolĂłgiĂĄnak egyre nagyobb teret hĂłdĂtĂł kutatĂĄsi terĂŒlete. ManapsĂĄg kĂŒlönbözĆ közössĂ©gek fejlesztĂ©sĂ©re van lehetĆsĂ©g. Hallhatunk iskolĂĄk, szervezetek, vĂĄllalatok, egyhĂĄzak vagy Ă©ppen telepĂŒlĂ©sek kĂŒlönfĂ©le közössĂ©geinek fejlesztĂ©sĂ©rĆl. Ezen tevĂ©kenysĂ©gek fontosak a tĂĄrsadalmi csoportok kohĂ©ziĂłjĂĄnak az elĆsegĂtĂ©sĂ©hez Ă©s fenntartĂĄsĂĄhoz.
Dolgozatom cĂ©lja, hogy kĂ©pet adjak a Baptista EgyhĂĄz közössĂ©gĂ©inek mƱködĂ©sĂ©rĆl, összetĂ©telĂ©rĆl, kialakulĂĄsĂĄrĂłl Ă©s Ă©rtĂ©krendszerĂ©rĆl. A kutatĂĄsom cĂ©lja az interjĂș alanyok vĂĄlaszain keresztĂŒl bemutatni a baptista gyĂŒlekezeteken belĂŒli közössĂ©gek kapcsolatainak rendszerĂ©t, összetettsĂ©gĂ©t, valamint azt, hogy a vĂĄlaszadĂłk mikĂ©nt vĂĄllalnak szerepet a gyĂŒlekezetĂŒk közössĂ©gĂ©nek Ă©pĂtĂ©sĂ©ben.
KutatĂĄsi mĂłdszerkĂ©nt az interjĂșt vĂĄlasztottam Ă©s hasznĂĄltam. FĂ©lig strukturĂĄlt interjĂșkkal dolgoztam.
Szakdolgozatomban hĂĄrom hipotĂ©zist fogalmaztam meg, amelyekre a vĂĄlaszokat a feltett kutatĂĄsi kĂ©rdĂ©seim alapjĂĄn kaptam meg. HipotĂ©ziseim rĂ©szben igaznak bizonyultak. A gyĂŒlekezetbe jĂĄrĂł tagok szeretnĂ©k, ha közössĂ©gĂŒk folyamatosan fejlĆdne, kapcsolataik erĆsödne.BSc/BASzociolĂłgi