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Aufsatz
SSPIM: a beam shaping toolbox for structured selective plane illumination microscopy
(2018-07-03)
Selective plane illumination microscopy (SPIM) represents a preferred method in dynamic tissue imaging, because it combines high spatiotemporal resolution with low phototoxicity. The OpenSPIM system was developed to provide an accessible and flexible microscope set-up for non-specialist users. Here, we report Structured SPIM (SSPIM), which offers an open-source, user-friendly and compact toolbox for beam shaping to be applied within the OpenSPIM platform. SSPIM is able to generate digital patterns for a wide range ...
Aufsatz
Direct evidence for radiative charge transfer after inner-shell excitation and ionization of large clusters
(2018-01-16)
We directly observe radiative charge transfer (RCT) in Ne clusters by dispersed vacuum-ultraviolet photon detection. The doubly ionized Ne^2+ – Ne_n-1 initial states of RCT are populated after resonant 1s–3p photoexcitation or 1s photoionization of Ne_n clusters with {n} \approx 2800. These states relax further producing Ne^+ – Ne^+ – Ne_n-2 final states, and the RCT photon is emitted. Ab initio calculations assign the observed RCT signal to the Ne^2+(2p^-2 [^1D]) - Ne_n-1 initial state, while transitions from other ...
Aufsatz
Circular Dichroism in Fluorescence Emission Following the C 1s→π* Excitation and Resonant Auger Decay of Carbon Monoxide
(2018-06-26)
Dichroism in angle-resolved spectra of circularly polarized fluorescence from freely-rotating CO molecules was studied experimentally and theoretically. For this purpose, carbon monoxide in the gas phase was exposed to circularly polarized soft X-ray synchrotron radiation. The photon energy was tuned across the C 1s→π* resonant excitation, which decayed via the participator Auger transition into the CO+ A 2Π state. The dichroic parameter β1 of the subsequent CO+ (A 2Π → X 2Σ+) visible fluorescence was measured by ...
Aufsatz
Fat-containing cells are eliminated during Dictyostelium development
(2017-09-15)
Triacylglycerol is a universal storage molecule for metabolic energy in living organisms. However, Dictyostelium amoebae, that have accumulated storage fat from added fatty acids do not progress through the starvation period preceding the development of the durable spore. Mutants deficient in genes of fat metabolism, such as fcsA, encoding a fatty acid activating enzyme, or dgat1 and dgat2, specifying proteins that synthesize triacylglycerol, strongly increase their chances to contribute to the spore fraction of the ...
Aufsatz
Extreme Ultraviolet to Visible Dispersed Single Photon Detection for Highly Sensitive Sensing of Fundamental Processes in Diverse Samples
(2018-05-23)
The detection of a single photon is the most sensitive method for sensing of photon emission. A common technique for single photon detection uses microchannel plate arrays combined with photocathodes and position sensitive anodes. Here, we report on the combination of such detectors with grating diffraction spectrometers, constituting a low-noise wavelength resolving photon spectroscopy apparatus with versatile applicability. We recapitulate the operation principle of such detectors and present the details of the ...
Aufsatz
Requirement of the Dynein-Adaptor Spindly for Mitotic and Post-Mitotic Functions in Drosophila
(2018-03-30)
Spindly was originally identified as a specific regulator of Dynein activity at the kinetochore. In early prometaphase, Spindly recruits the Dynein/Dynactin complex, promoting the establishment of stable kinetochore-microtubule interactions and progression into anaphase. While details of Spindly function in mitosis have been worked out in cultured human cells and in the C. elegans zygote, the function of Spindly within the context of an organism has not yet been addressed. Here, we present loss- and gain-of-function ...
Aufsatz
Protein Phosphatase Sit4 Affects Lipid Droplet Synthesis and Soraphen A Resistance Independent of Its Role in Regulating Elongator Dependent tRNA Modification
(2018-07-11)
The protein phosphatase Sit4 has been shown to be required for lipogenesis and resistance against the acetyl-CoA carboxylase inhibitor soraphen A. Since Sit4 is also required for biosynthesis of Elongator dependent tRNA modifications such as 5-methoxycarbonylmethyluridine (mcm5U), we investigated the relevance of tRNA modifications in lipogenesis and soraphen A response. While sit4 and Elongator (elp3) mutants copy defects in mcm5U formation and stress sensitivity, they do not share soraphen A sensitivity and low ...
Dissertation
Donor-stabilisierte Bisphosphanyl-Tetrylene
(2018-09)
Gegenstand dieser Arbeit war die Untersuchung der Darstellbarkeit Bisphosphanyl-substituierter, schwerer Tetrylene mit 1,1‘-Ferrocenylenrückgrat war. Die Synthese freier, stabiler Bisphosphanyl-Tetrylene gelang aufgrund sterischer und elektronischer Gründe nicht, jedoch konnten NHC-stabilisierte Addukte (Si, Sn, Pb), intermolekular stabilisierte, dimere Donor-Akzeptor Addukte (Sn, Pb) und intramolekular stabilisierte Donor-Akzeptor-Addukte (Pb) isoliert, charakterisiert und deren Reaktionsverhalten untersucht werden.
Im ...
Aufsatz
No Evidence for Ionotropic Pheromone Transduction in the Hawkmoth Manduca sexta
(2016-11-09)
Insect odorant receptors (ORs) are 7-transmembrane receptors with inverse membrane topology. They associate with the conserved ion channel Orco. As chaperon, Orco maintains ORs in cilia and, as pacemaker channel, Orco controls spontaneous activity in olfactory receptor neurons. Odorant binding to ORs opens OR-Orco receptor ion channel complexes in heterologous expression systems. It is unknown, whether this also occurs in vivo. As an alternative to this ionotropic transduction, experimental evidence is accumulating ...
Dissertation
Mechanistic Insights into the intrinsic Kinase Regulation of LRRK2
(2019-06)
Obwohl Morbus Parkinson (PD) die zweithäufigste neurodegenerative Erkrankung darstellt, ist der Pathomechanismus kaum verstanden. Es ist jedoch erwiesen, dass PD assoziierte Mutationen die Aktivität der Leucine rich repeat kinase 2 (LRRK2) beeinflussen, sodass diese ein potentielles Drug Target darstellt. Für ein besseres Verständnis wurden daher der intrinsische regulatorische Mechanismus und der Einfluss von Mutationen auf LRRK2 untersucht. Zusätzlich wurde der Einfluss von Nanobodies gegen die ROC Domäne von LRRK2 ...