Sensitive Spectroscopic Detection of Large and Denatured Protein Aggregates in Solution by Use of the Fluorescent Dye Nile Red

The fluorescent dye Nile red was used as a probe for the sensitive detection of large, denatured aggregates of the model protein β-galactosidase (E. coli) in solution. Aggregates were formed by irreversible heat denaturation of β-galactosidase below and above the protein’s unfolding temperature of 57.4°C, and the presence of aggregates in heated solutions was confirmed by static light scattering. Interaction of Nile red with β-galactosidase aggregates led to a shift of the emission maximum (λmax) from 660 to 611 nm, and to an increase of fluorescence intensity. Time-resolved fluorescence and fluorescence correlation spectroscopy (FCS) measurements showed that Nile red detected large aggregates with hydrodynamic radii around 130 nm. By steady-state fluorescence measurements, it was possible to detect 1 nM of denatured and aggregated β-galactosidase in solution. The comparison with size exclusion chromatography (SEC) showed that native β-galactosidase and small aggregates thereof had no substantial effect on the fluorescence of Nile red. Large aggregates were not detected by SEC, because they were excluded from the column. The results with β-galactosidase demonstrate the potential of Nile red for developing complementary analytical methods that overcome the size limitations of SEC, and can detect the formation of large protein aggregates at early stages

Gene expression profiling for molecular distinction and characterization of laser captured primary lung cancers

<p>Abstract</p> <p>Methods</p> <p>We examined gene expression profiles of tumor cells from 29 untreated patients with lung cancer (10 adenocarcinomas (AC), 10 squamous cell carcinomas (SCC), and 9 small cell lung cancer (SCLC)) in comparison to 5 samples of normal lung tissue (NT). The European and American methodological quality guidelines for microarray experiments were followed, including the stipulated use of laser capture microdissection for separation and purification of the lung cancer tumor cells from surrounding tissue.</p> <p>Results</p> <p>Based on differentially expressed genes, different lung cancer samples could be distinguished from each other and from normal lung tissue using hierarchical clustering. Comparing AC, SCC and SCLC with NT, we found 205, 335 and 404 genes, respectively, that were at least 2-fold differentially expressed (estimated false discovery rate: < 2.6%). Different lung cancer subtypes had distinct molecular phenotypes, which also reflected their biological characteristics. Differentially expressed genes in human lung tumors which may be of relevance in the respective lung cancer subtypes were corroborated by quantitative real-time PCR.</p> <p>Genetic programming (GP) was performed to construct a classifier for distinguishing between AC, SCC, SCLC, and NT. Forty genes, that could be used to correctly classify the tumor or NT samples, have been identified. In addition, all samples from an independent test set of 13 further tumors (AC or SCC) were also correctly classified.</p> <p>Conclusion</p> <p>The data from this research identified potential candidate genes which could be used as the basis for the development of diagnostic tools and lung tumor type-specific targeted therapies.</p

Beitraege zur thermischen und dynamischen Analyse einer freischwingenden Stirling-Kleinkaeltemaschine

SIGLEAvailable from TIB Hannover: DW 5949 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Young's modulus and tensile strength of CuNi(Mn) thin films on polyimide foils by tensile testing

Macionczyk F, Bruckner W, Pitschte W, Reiss G. Young's modulus and tensile strength of CuNi(Mn) thin films on polyimide foils by tensile testing. Journal of Materials Research. 1998;13(10):2852-2858.Force-strain curves were measured for 1.0 mu m and 1.5 mu m thick Cu0.57Ni0.42Mn0.01 films on 8 mu m thick polyimide foils by tensile testing. By separating the force working on the polyimide foil from that working on the metal-polyimide compound, stress-strain curves for the CuNi(Mn) films were obtained. Young's modulus and tensile strength were determined for as-deposited and annealed [350 degrees C, 1 h, N-2/H-2 (5 vol %) atmosphere] films by this method. Crack propagation starts at the end of the elastic region at 0.2 to 0.7% strain, depending on the film thickness and the thermal treatment. The cracking behavior is described by a steady-state approximation

Investigation of heat treatment and deformation processes of BPSCCO-2223/Ag conductors

Fahr T, Hütten A, Pitschke W, et al. Investigation of heat treatment and deformation processes of BPSCCO-2223/Ag conductors. APPLIED SUPERCONDUCTIVITY 1997, VOLS 1 AND 2: VOL 1: SMALL SCALE AND ELECTRONIC APPLICATIONS; VOL 2: LARGE SCALE AND POWER APPLICATIONS. 1997;(158):961-964.This paper presents results of thermoanalytical and XRD investigations at room temperature and in a high temperature chamber concerning the early stage of the transformation of precursors for the fabrication of Bi,Pb-2223 I Ag tapes. The occurence of two parallel reactions is suggested at the beginning of reaction annealing of the conductors, (i) the formation of Bi,Pb-2212 from the ph free phase and (ii) the formation of a liquid phase accelerating the Bi,Pb-2223 phase formation. High temperature XRD experiments show the appearence of a preferential orientation of the 2212 phase in the period of heating the tape to the reaction temperature. A second part shows the dependence of the microhardness and sausaging in monofilamentary tapes on rolling parameters as well as results of the production of a multifilamentary tape with 99 filaments and a length of 550 m, where a critical current density of 25,8 kA/cm(2) was achieved