University of Münster

About: University of Münster is a education organization based out in Münster, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 35609 authors who have published 69059 publications receiving 2278534 citations. The organization is also known as: University of Munster & University of Muenster.

Multicolor bimolecular fluorescence complementation reveals simultaneous formation of alternative CBL/CIPK complexes in planta

Abstract: The specificity of intracellular signaling and developmental patterning in biological systems relies on selective interactions between different proteins in specific cellular compartments. The identification of such protein-protein interactions is essential for unraveling complex signaling and regulatory networks. Recently, bimolecular fluorescence complementation (BiFC) has emerged as a powerful technique for the efficient detection of protein interactions in their native subcellular localization. Here we report significant technical advances in the methodology of plant BiFC. We describe a series of versatile BiFC vector sets that are fully compatible with previously generated vectors. The new vectors enable the generation of both C-terminal and N-terminal fusion proteins and carry optimized fluorescent protein genes that considerably improve the sensitivity of BiFC. Using these vectors, we describe a multicolor BiFC (mcBiFC) approach for the simultaneous visualization of multiple protein interactions in the same cell. Application to a protein interaction network acting in calcium-mediated signal transduction revealed the concurrent interaction of the protein kinase CIPK24 with the calcium sensors CBL1 and CBL10 at the plasma membrane and tonoplast, respectively. We have also visualized by mcBiFC the simultaneous formation of CBL1/CIPK1 and CBL9/CIPK1 protein complexes at the plasma membrane. Thus, mcBiFC provides a useful new tool for exploring complex regulatory networks in plants.

An ancient light-harvesting protein is critical for the regulation of algal photosynthesis

Abstract: Light is necessary for photosynthesis, but its absorption by pigment molecules such as chlorophyll can cause severe oxidative damage and result in cell death. The excess absorption of light energy by photosynthetic pigments has led to the evolution of protective mechanisms that operate on the timescale of seconds to minutes and involve feedback-regulated de-excitation of chlorophyll molecules in photosystem II (qE). Despite the significant contribution of eukaryotic algae to global primary production, little is known about their qE mechanism, in contrast to that in flowering plants. Here we show that a qE-deficient mutant of the unicellular green alga Chlamydomonas reinhardtii, npq4, lacks two of the three genes encoding LHCSR (formerly called LI818). This protein is an ancient member of the light-harvesting complex superfamily, and orthologues are found throughout photosynthetic eukaryote taxa, except in red algae and vascular plants. The qE capacity of Chlamydomonas is dependent on environmental conditions and is inducible by growth under high light conditions. We show that the fitness of the npq4 mutant in a shifting light environment is reduced compared to wild-type cells, demonstrating that LHCSR is required for survival in a dynamic light environment. Thus, these data indicate that plants and algae use different proteins to dissipate harmful excess light energy and protect the photosynthetic apparatus from damage.

Consensus on Microembolus Detection by TCD

Abstract: Transcranial Doppler ultrasound is capable of detecting microembolic material, both gaseous and solid, within the intracranial cerebral arteries. To avoid discrediting this promising and exciting new technique, experts in this field met in January 1997 in Frankfurt, Germany, to discuss the limitations and problems of embolus detection and to determine guidelines for its proper use in clinical practice, as well as in scientific investigations. In particular, the authors suggest that studies report the following parameters: (1) ultrasound device, (2) transducer type and size, (3) insonated artery, (4) insonation depth, (5) algorithms for signal intensity measurement, (6) scale settings, (7) detection threshold, (8) axial extension of sample volume, (9) fast Fourier transform (FFT) size (number of points used), (10) FFT length (time), (11) FFT overlap, (12) transmitted ultrasound frequency, (13) high-pass filter settings, and (14) recording time. There was agreement that no current system of automatic embolus detection has the required sensitivity and specificity for clinical use.

The desorption process in MALDI.

Abstract: A matrix-assisted laser desorption ionization (MALDI) “event” constitutes a complex process, involving optical and mechanical phenomena as well as thermodynamic and physicochemical processes of phase transition and ionization. A successful MALDI analysis encompasses several crucial steps: sample preparation, excitation of sample and disintegration of the condensed phase, generation and separation of charges and ionization of analyte molecules, and, finally, extraction, separation according to the massto-charge ratio of the ions in the mass spectrometer, and detection. Despite the rapid acceptance of the method in chemistry and biomedicine after its introduction by Karas and Hillenkamp,1-4 the underlying mechanisms have been less well understood for a long time and a more comprehensive picture has only recently begun to emerge. Systematic variation of one or more of the relevant “input” parameters is one of the most straightforward experimental tools to obtain insight into the involved mechanisms, and has consequently been utilized in a large number of fundamental studies. The role of the different relevant irradiation (laser) parameters in the desorption/ionization process, as well as those of the matrix and the preparation protocol, have been addressed in these investigations. These included, for example, the role of the laser wavelength, pulse duration, and laser fluence (laser energy per pulse and unit area) for the laser parameters (addressed in section III), and the type of (co-)crystallization and the matter of the incorporation of analyte molecules into matrix crystals for the material side (section IV). In other work, the dynamical parameters of the expanding MALDI particle “plume” have been addressed (section V): the initial kinetic energies and energy distributions of molecules and ions, and the composition of the plume (ion-to-neutral ratio and ejection of particles and clusters versus the emission of molecular constituents). Several researchers have developed theoretical models for the desorption as well as the ionization * E-mail: dreisew@uni-muenster.de. Fax +49-251-8355121. Tel. +49-251-8356726. Klaus Dreisewerd was born in Beckum, Germany, in 1961. He received his diploma in Physics from the University of Münster in 1990 and his Ph.D. degree in 1995 under the supervision of Franz Hillenkamp. He moved to the Free University of Amsterdam as a post-doc in the molecular neurobiology department at the end of 1994 and returned to the Münster institute in 1997. His main current interests are in the field of MALDI fundamentals and that of MALDI-MS with pulsed infrared lasers (IRMALDI). 395 Chem. Rev. 2003, 103, 395−425