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We describe a novel variant of fluorescence lifetime imaging microscopy (FLIM), denoted anisotropy-FLIM or rFLIM, which enables the wide-field measurement of the anisotropy decay of fluorophores on a pixel-by-pixel basis. We adapted existing frequency-domain FLIM technology for rFLIM by introducing linear polarizers in the excitation and emission paths. The(More)
The green fluorescent protein (GFP) of the bioluminescent jellyfish Aequorea and its mutants have gained widespread usage as an indicator of structure and function within cells. Proton transfer has been implicated in the complex photophysics of the wild-type molecule, exhibiting a protonated A species excited at 400 nm, and two deprotonated excited-state(More)
We report investigations of resonance energy transfer in the green fluorescent protein and calmodulin-based fluorescent indicator constructs for Ca(2+) called cameleons using steady-state and time-resolved spectroscopy of the full construct and of the component green fluorescent protein mutants, namely ECFP (donor) and EYFP (acceptor). EYFP displays a(More)
The amyloid peptides Aβ(40) and Aβ(42) of Alzheimer's disease are thought to contribute differentially to the disease process. Although Aβ(42) seems more pathogenic than Aβ(40), the reason for this is not well understood. We show here that small alterations in the Aβ(42):Aβ(40) ratio dramatically affect the biophysical and biological properties of the Aβ(More)
Alpha-synuclein is the major component of Lewy bodies and Lewy neurites, which are granular and filamentous protein inclusions that are the defining pathological features of several neurodegenerative conditions such as Parkinson's disease. Fibrillar aggregates formed from alpha-synuclein in vitro resemble brain-derived material, but the role of such(More)
The cellular polyamines putrescine, spermidine, and spermine accelerate the aggregation and fibrillization of alpha-synuclein, the major protein component of Lewy bodies associated with Parkinson's disease. Circular dichroism and fluorometric thioflavin T kinetic studies showed a transition of alpha-synuclein from unaggregated to highly aggregated states,(More)
The fibrillization of α-synuclein (α-syn) is a key event in the pathogenesis of α-synucleinopathies. Mutant α-syn (A53T, A30P, or E46K), each linked to familial Parkinson's disease, has altered aggregation properties, fibril morphologies, and fibrillization kinetics. Besides α-syn, Lewy bodies also contain several associated proteins including small heat(More)
The aggregation of alpha-synuclein, involved in the pathogenesis of several neurodegenerative disorders such as Parkinson's disease, is enhanced in vitro by biogenic polyamines binding to the highly charged C-terminal region aa109-140. In this study, we investigated the influence of this region on the aggregation kinetics, monitored by thioflavin T binding(More)
We report the application of an integrated optical Young interferometer sensor for ultrasensitive, real-time, direct detection of viruses. We have validated the sensor by detecting herpes simplex virus type 1 (HSV-1), but the principle is generally applicable. Detection of HSV-1 virus particles was performed by applying the virus sample onto a sensor(More)
Mature, active mammalian histidine decarboxylase is a dimeric enzyme of carboxy-truncated monomers (approximately 53 kDa). By using a biocomputational approach, we have generated a three-dimensional model of a recombinant 1/512 fragment of the rat enzyme, which shows kinetic constants similar to those of the mature enzyme purified from rodent tissues. This(More)