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Flavin-binding fluorescent proteins (FPs) are genetically encoded in vivo reporters, which are derived from microbial and plant LOV photoreceptors. In this study, we comparatively analyzed ROS formation and light-driven antimicrobial efficacy of eleven LOV-based FPs. In particular, we determined singlet oxygen ( 1 O 2 ) quantum yields and superoxide photosensitization activities via spectroscopic assays and performed cell toxicity experiments in E . coli . Besides miniSOG and SOPP, which have been engineered to generate 1 O 2 , all of the other tested flavoproteins were able to produce singlet oxygen and/or hydrogen peroxide but exhibited remarkable differences in ROS selectivity and yield. Accordingly, most LOV-FPs are potent photosensitizers, which can be used for light-controlled killing of bacteria. Furthermore, the two variants Pp2FbFP and DsFbFP M49I, exhibiting preferential photosensitization of singlet oxygen or singlet oxygen and superoxide, respectively, were shown to be new tools for studying specific ROS-induced cell signaling processes. The tested LOV-FPs thus further expand the toolbox of optogenetic sensitizers usable for a broad spectrum of microbiological and biomedical applications.

Background Light, oxygen, voltage (LOV) domains are widely distributed in plants, algae, fungi, bacteria, and represent the photo-responsive domains of various blue-light photoreceptor proteins. Their photocycle involves the blue-light triggered adduct formation between the C(4a) atom of a non-covalently bound flavin chromophore and the sulfur atom of a conserved cysteine in the LOV sensor domain. LOV proteins show considerable variation in the structure of N- and C-terminal elements which flank the LOV core domain, as well as in the lifetime of the adduct state. Results Here, we report the photochemical, structural and functional characterization of DsLOV, a LOV protein from the photoheterotrophic marine α-proteobacterium Dinoroseobacter shibae which exhibits an average adduct state lifetime of 9.6 s at 20°C, and thus represents the fastest reverting bacterial LOV protein reported so far. Mutational analysis in D. shibae revealed a unique role of DsLOV in controlling the induction of photopigment synthesis in the absence of blue-light. The dark state crystal structure of DsLOV determined at 1.5 Å resolution reveals a conserved core domain with an extended N-terminal cap. The dimer interface in the crystal structure forms a unique network of hydrogen bonds involving residues of the N-terminus and the β-scaffold of the core domain. The structure of photoexcited DsLOV suggests increased flexibility in the N-cap region and a significant shift in the Cα backbone of β strands in the N- and C-terminal ends of the LOV core domain. Conclusions The results presented here cover the characterization of the unusual short LOV protein DsLOV from Dinoroseobacter shibae including its regulatory function, extremely fast dark recovery and an N-terminus mediated dimer interface. Due to its unique photophysical, structural and regulatory properties, DsLOV might thus serve as an alternative model system for studying light perception by LOV proteins and physiological responses in bacteria.

Enrolling in a clinical trial or study requires informed consent. Furthermore, it is crucial to ensure proper consent when storing samples in biobanks for future research, as these samples may be used in studies beyond their initial purpose. For pediatric studies, consent must be obtained from both the child and their legal guardians, requiring the recording of multiple consents at once. Electronic consent has become more popular recently due to its ability to prevent errors and simplify the documentation of multiple consents. However, integrating consent capture into existing study software structures remains a challenge. This report evaluates the usability of the generic Informed Consent Service (gICS) of the University Medicine Greifswald (UMG) for obtaining electronic consent in pediatric studies. The setup was designed to integrate seamlessly with the current infrastructure and meet the specific needs of a multi-user, multi-study environment. The study was conducted in a pediatric research setting, where additional informed consent was obtained separately for the biobank. Over a period of 54 weeks, 1061 children and adolescents aged 3 to 17 years participated in the study. Out of these, 348 agreed also to participate in the biobank. The analysis included a total of 2066 consents and assents, with 945 paper-based and 1121 electronic consents. The study assessed the error susceptibility of electronic versus paper-based consents and found a significant reduction rate of errors of 94.7%. These findings provide valuable insights into the use of gICS in various studies and the practical implementation of electronic consent software in pediatric medicine.

Dilepton production in heavy-ion collisions at top SPS energy is investigated within a coarse-graining approach that combines an underlying microscopic evolution of the nuclear reaction with the application of medium-modified spectral functions. Extracting local energy and baryon density for a grid of small space-time cells and going to each cell’s rest frame enables to determine local temperature and chemical potential by application of an equation of state. This allows for the calculation of thermal dilepton emission. We apply and compare two different spectral functions for the ρ: A hadronic many-body calculation and an approach that uses empirical scattering amplitudes. Quantitatively good agreement of the model calculations with the data from the NA60 collaboration is achieved for both spectral functions, but in detail the hadronic many-body approach leads to a better description, especially of the broadening around the pole mass of the ρ and for the low-mass excess. We further show that the presence of a pion chemical potential significantly influences the dilepton yield.

The production of lepton pairs in elementary and nucleus-nucleus collisions at SIS energies is studied within the Ultra-relativistic Quantum Molecular Dynamics transport approach. In comparison to previous calculations, we now included an improved treatment of the Delta sub(1232) resonance. The resulting invariant mass and transverse momentum spectra are compared to available HADES data. In general, our results give a good description of the data. With regard to the observed overestimation of the [rho] contribution, the different production channels and the respective production cross-sections are investigated. A problem remains the lack of experimental data for cross-sections and branching ratios of intermediate baryonic resonances, which are crucial for the [rho] production. However, recent HADES cross-section measurements close to the [rho] threshold might help to further constrain the model parameters.

We present a study of the elliptic flow and \\[R_AA\\] of \\[ D\\] and \\[ D\\] mesons in Au+Au collisions at FAIR energies. We propagate the charm quarks and the \\[ D\\] mesons following a previously applied Langevin dynamics. The evolution of the background medium is modeled in two different ways: (I) we use the UrQMD hydrodynamics + Boltzmann transport hybrid approach including a phase transition to QGP and (II) with the coarse-graining approach employing also an equation of state with QGP. The latter approach has previously been used to describe di-lepton data at various energies very successfully. This comparison allows us to explore the effects of partial thermalization and viscous effects on the charm propagation. We explore the centrality dependencies of the collisions, the variation of the decoupling temperature and various hadronization parameters. We find that the initial partonic phase is responsible for the creation of most of the \\[ D/ D\\] mesons elliptic flow and that the subsequent hadronic interactions seem to play only a minor role. This indicates that \\[ D/ D\\] mesons elliptic flow is a smoking gun for a partonic phase at FAIR energies. However, the results suggest that the magnitude and the details of the elliptic flow strongly depend on the dynamics of the medium and on the hadronization procedure, which is related to the medium properties as well. Therefore, even at FAIR energies the charm quark might constitute a very useful tool to probe the quark–gluon plasma and investigate its physics.

We calculate dilepton spectra in heavy-ion collisions using a coarse-graining approach to the simulation of the created medium with the UrQMD transport model. This enables the use of dilepton-production rates evaluated in equilibrium quantum-field theory at finite temperatures and chemical potentials.

We investigate dilepton production in transport-based approaches and show that the baryon couplings of the ρ meson represent the most important ingredient for understanding the measured dilepton spectra. At SIS energies, the baryon resonances naturally play a major role and affect already the vacuum spectra via Dalitz-like contributions, which can be captured well in transport simulations. Recent pion-beam measurements at GSI will help to constrain the properties of the involved resonances further.

We use a coarse-graining approach to extract local thermodynamic properties from simulations with a microscopic transport model by averaging over a large ensemble of events. Setting up a grid of small space-time cells and going into each cell's rest frame allows to determine baryon and energy density. With help of an equation of state we get the corresponding temperature T and baryon-chemical potential μB. These results are used for the calculation of the thermal dilepton yield. We apply and compare two different spectral functions for the ρ meson, firstly a calculation from hadronic many-body theory and secondly a calculation from experimental scattering amplitudes. The results obtained with our approach are compared to measurements of the NA60 Collaboration. A relatively good description of the data is achieved with both spectral functions. However, the hadronic many-body calculation is found to be closer to the experimental data with regard to the in-medium broadening of the spectral shape.

We present transport calculations with the Ultra-relativistic Quantum Molecular Dynamics approach (UrQMD) for dilepton spectra at SIS energies and simulations for NA60 within a coarse-graining approach. While the transport model obtains a good agreement with experiment for elementary reactions, in heavy-ion collisions an excess in the invariant mass spectra is observed which cannot be described by the model. As the pure transport calculations do not include explicit in-medium effects and are limited to hadronic degrees of freedom, we present an alternative approach that uses coarse-grained output from transport calculations to determine thermal dilepton emission rates. For this we apply the medium-modified ρ spectral function by Eletsky et al. In a first exemplary comparison to data from the NA60 experiment we find that the coarse-graining approach gives reasonable results.