Functional characterization of two-dimensional gel-separated proteins using sequential staining

Proteins separated by two-dimensional (2-D) gel electrophoresis can be visualized using various protein staining methods. This is followed by downstream procedures, such as image analysis, gel spot cutting, protein digestion, and mass spectrometry (MS), to characterize protein expression profiles within cells, tissues, organisms, or body fluids. Characterizing specific post-translational modifications on proteins using MS of peptide fragments is difficult and labor-intensive. Recently, specific staining methods have been developed and merged into the 2-D gel platform so that not only general protein patterns but also patterns of phosphorylated and glycosylated proteins can be obtained. We used the new Pro-Q Diamond phosphoprotein dye technology for the fluorescent detection of phosphoproteins directly in 2-D gels of mouse leukocyte proteins, and Pro-Q Emerald 488 glycoprotein dye to detect glycoproteins. These two fluorescent stains are compatible with general protein stains, such as SYPRO Ruby stain. We devised a sequential procedure using Pro-Q Diamond (phosphoprotein), followed by Pro-Q Emerald 488 (glycoprotein), followed by SYPRO Ruby stain (general protein stain), and finally silver stain for total protein profile. This multiple staining of the proteins in a single gel provided parallel determination of protein expression and preliminary characterization of post-translational modifications of proteins in individual spots on 2-D gels. Although this method does not provide the same degree of certainty as traditional MS methods of characterizing post-translational modifications, it is much simpler, faster, and does not require sophisticated equipment and expertise in MS.     

Advanced high-performance liquid chromatography method for highly polar nitroaromatic compounds in ground water samples from ammunition waste sites

An advanced HPLC-photodiode array detection method for the determination of 12 selected highly polar nitroaromatic compounds in ground water samples of ammunition waste sites has been developed and validated. After solid-phase extraction the limits of detection were in the range 0.1–0.5 μg/l. To prove the applicability of the method to other polar nitroaromatic compounds the retention time of another 32 polar compounds under the specified chromatographic conditions were determined and their UV spectra recorded. To review the method, interlaboratory comparisons were performed with a spiked and a real ground water sample.     

Die Hartree-Fock-Theorie mit Zwischenzuständen: Klärung ihrer Struktur bei Zeitumkehrinvarianz und Anwendung auf das Kleinsche Rotations-Vibrationsmodell

In an earlier paper we have extended the new Tamm-Dancoff method to the “New Tamm-Dancoff method with intermediate states”. This extension makes it possible to treat the effect of nearby levels in many body systems with Green's functions. In addition to well-known approximations, such as the Hartree-Fock theory and the Hartree-Bogoliubov theory, we obtain a series of new approximations. The “Hartree-Fock theory with intermediate states”, which is the subject of the present investigation, is one of these. By using time reversal invariance we have succeeded in clarifying its structure, and we give the solution procedure. The exchange terms in theN-particle intermediate states can be represented by an additional potentialY, which (as is the case for the generalized density matrixρ) has to be determined selfconsistently. In this way we have overcome the difficulties, that Kerman and Klein met in their “generalized Hartree-Fock approximation”, which has some close similarities with our Hartree-Fock theory with intermediate states. We demonstrate our method for the exactly soluble rotational-vibrational model of Klein et al. Hereby we show how to treat conservation laws and the degeneracy of levels. The Hartree-Fock equations with three intermediate states turn out to give analytical expressions for the energies and the matrix elements. These agree excellently with the exact values in the rotational part of the spectrum.     

A numerical solution of a nonlinear Langevin Equation

A one-dimensional Langevin Equation in which the friction term and the stochastic force term depend nonlinearly on the velocity is presented. Assuming that the Maxwell distribution is the stationary solution of the Fokker Planck Equation (which is equivalent to the nonlinear Langevin Equation) we derive a generalization of the Fluctuation Dissipation theorem. A numerical algorithm is developed which allows us to integrate the nonlinear Langevin Equation. From this numerical solution correlation functions are obtained.     

Synthese des sesquiterpens (±)-chiloscyphon

The revised structure of chiloscyphone ({=1}) is confirmed by total synthesis: {=4a},{=b}, obtained by stereoselective cyclization of {=2}, were transformed to {=8}. Ketone {=8} was converted to (±)-1 by direct α-methylenation.