@article{PetersFohmannRudeletal.2021, author = {Peters, Simon and Fohmann, Ingo and Rudel, Thomas and Schubert-Unkmeir, Alexandra}, title = {A Comprehensive Review on the Interplay between Neisseria spp. and Host Sphingolipid Metabolites}, series = {Cells}, volume = {10}, journal = {Cells}, number = {11}, issn = {2073-4409}, doi = {10.3390/cells10113201}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250203}, year = {2021}, abstract = {Sphingolipids represent a class of structural related lipids involved in membrane biology and various cellular processes including cell growth, apoptosis, inflammation and migration. Over the past decade, sphingolipids have become the focus of intensive studies regarding their involvement in infectious diseases. Pathogens can manipulate the sphingolipid metabolism resulting in cell membrane reorganization and receptor recruitment to facilitate their entry. They may recruit specific host sphingolipid metabolites to establish a favorable niche for intracellular survival and proliferation. In contrast, some sphingolipid metabolites can also act as a first line defense against bacteria based on their antimicrobial activity. In this review, we will focus on the strategies employed by pathogenic Neisseria spp. to modulate the sphingolipid metabolism and hijack the sphingolipid balance in the host to promote cellular colonization, invasion and intracellular survival. Novel techniques and innovative approaches will be highlighted that allow imaging of sphingolipid derivatives in the host cell as well as in the pathogen.}, language = {en} } @article{LibreSeisslerGuerreroetal.2021, author = {Libre, Camille and Seissler, Tanja and Guerrero, Santiago and Batisse, Julien and Verriez, C{\´e}dric and Stupfler, Benjamin and Gilmer, Orian and Cabrera-Rodriguez, Romina and Weber, Melanie M. and Valenzuela-Fernandez, Agustin and Cimarelli, Andrea and Etienne, Lucie and Marquet, Roland and Paillart, Jean-Christophe}, title = {A conserved uORF regulates APOBEC3G translation and is targeted by HIV-1 Vif protein to repress the antiviral factor}, series = {Biomedicines}, volume = {10}, journal = {Biomedicines}, number = {1}, issn = {2227-9059}, doi = {10.3390/biomedicines10010013}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252147}, year = {2021}, abstract = {The HIV-1 Vif protein is essential for viral fitness and pathogenicity. Vif decreases expression of cellular restriction factors APOBEC3G (A3G), A3F, A3D and A3H, which inhibit HIV-1 replication by inducing hypermutation during reverse transcription. Vif counteracts A3G at several levels (transcription, translation, and protein degradation) that altogether reduce the levels of A3G in cells and prevent its incorporation into viral particles. How Vif affects A3G translation remains unclear. Here, we uncovered the importance of a short conserved uORF (upstream ORF) located within two critical stem-loop structures of the 5′ untranslated region (5′-UTR) of A3G mRNA for this process. A3G translation occurs through a combination of leaky scanning and translation re-initiation and the presence of an intact uORF decreases the extent of global A3G translation under normal conditions. Interestingly, the uORF is also absolutely required for Vif-mediated translation inhibition and redirection of A3G mRNA into stress granules. Overall, we discovered that A3G translation is regulated by a small uORF conserved in the human population and that Vif uses this specific feature to repress its translation.}, language = {en} } @article{HaackHauckKlingenbergetal.2021, author = {Haack, J. and Hauck, C. and Klingenberg, C. and Pirner, M. and Warnecke, S.}, title = {A Consistent BGK Model with Velocity-Dependent Collision Frequency for Gas Mixtures}, series = {Journal of Statistical Physics}, volume = {184}, journal = {Journal of Statistical Physics}, number = {3}, issn = {1572-9613}, doi = {10.1007/s10955-021-02821-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-269146}, pages = {31}, year = {2021}, abstract = {We derive a multi-species BGK model with velocity-dependent collision frequency for a non-reactive, multi-component gas mixture. The model is derived by minimizing a weighted entropy under the constraint that the number of particles of each species, total momentum, and total energy are conserved. We prove that this minimization problem admits a unique solution for very general collision frequencies. Moreover, we prove that the model satisfies an H-Theorem and characterize the form of equilibrium.}, language = {en} } @article{FakhriLatifi2021, author = {Fakhri, Seyed Arvin and Latifi, Hooman}, title = {A consumer grade UAV-based framework to estimate structural attributes of coppice and high oak forest stands in semi-arid regions}, series = {Remote Sensing}, volume = {13}, journal = {Remote Sensing}, number = {21}, issn = {2072-4292}, doi = {10.3390/rs13214367}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248469}, year = {2021}, abstract = {Semi-arid tree covers, in both high and coppice growth forms, play an essential role in protecting water and soil resources and provides multiple ecosystem services across fragile ecosystems. Thus, they require continuous inventories. Quantification of forest structure in these tree covers provides important measures for their management and biodiversity conservation. We present a framework, based on consumer-grade UAV photogrammetry, to separately estimate primary variables of tree height (H) and crown area (A) across diverse coppice and high stands dominated by Quercus brantii Lindl. along the latitudinal gradient of Zagros mountains of western Iran. Then, multivariate linear regressions were parametrized with H and A to estimate the diameter at breast height (DBH) of high trees because of its importance to accelerate the existing practical DBH inventories across Zagros Forests. The estimated variables were finally applied to a model tree aboveground biomass (AGB) for both vegetative growth forms by local allometric equations and Random Forest models. In each step, the estimated variables were evaluated against the field reference values, indicating practically high accuracies reaching root mean square error (RMSE) of 0.68 m and 4.74 cm for H and DBH, as well as relative RMSE < 10\% for AGB estimates. The results generally suggest an effective framework for single tree-based attribute estimation over mountainous, semi-arid coppice, and high stands.}, language = {en} } @article{SeibelVolmer2021, author = {Seibel, Sebastian and Volmer, Judith}, title = {A Diary Study on Anticipated Leisure Time, Morning Recovery, and Employees' Work Engagement}, series = {International Journal of Environmental Research and Public Health}, volume = {18}, journal = {International Journal of Environmental Research and Public Health}, number = {18}, issn = {1660-4601}, doi = {10.3390/ijerph18189436}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246090}, year = {2021}, abstract = {Recovery during yesterday's leisure time is beneficial for morning recovery, and morning recovery fosters employees' work engagement, a positive, motivational state associated with job performance. We extended existing research by assuming that both, morning recovery (considered a resource) and anticipated leisure time (considered an anticipated resource gain), relate to work engagement. Anticipated leisure time comprises two constructs: general anticipation of leisure time, which refers to employees' cognitive evaluation of their entire upcoming leisure time, and pleasant anticipation of a planned leisure activity, which describes a positive affective reaction because of one specific, upcoming leisure activity. We suggested that employees with high pleasant anticipation generate more thoughts of a planned leisure activity (ToPLA), which may distract them from their work, reducing their work engagement. A diary study over five days showed that morning recovery and general anticipation of leisure time were positively related to work engagement. Furthermore, employees with higher pleasant anticipation of a planned leisure activity reported more ToPLA. In contrast to our expectations, neither pleasant anticipation nor ToPLA was related to work engagement. In sum, this study introduced anticipated leisure time as a novel antecedent of work engagement and demonstrated that anticipated resource gains are important for high work engagement.}, language = {en} } @article{EisenhuthVellmerRauhetal.2021, author = {Eisenhuth, Nicole and Vellmer, Tim and Rauh, Elisa T. and Butter, Falk and Janzen, Christian J.}, title = {A DOT1B/Ribonuclease H2 Protein Complex Is Involved in R-Loop Processing, Genomic Integrity, and Antigenic Variation in Trypanosoma brucei}, series = {mbio}, volume = {12}, journal = {mbio}, number = {6}, doi = {10.1128/mBio.01352-21}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260698}, pages = {e01352-21}, year = {2021}, abstract = {The parasite Trypanosoma brucei periodically changes the expression of protective variant surface glycoproteins (VSGs) to evade its host's immune sys-tem in a process known as antigenic variation. One route to change VSG expres-sion is the transcriptional activation of a previously silent VSG expression site (ES), a subtelomeric region containing the VSG genes. Homologous recombination of a different VSG from a large reservoir into the active ES represents another route. The conserved histone methyltransferase DOT1B is involved in transcriptional silencing of inactive ES and influences ES switching kinetics. The molecular machin-ery that enables DOT1B to execute these regulatory functions remains elusive, however. To better understand DOT1B-mediated regulatory processes, we purified DOT1B-associated proteins using complementary biochemical approaches. We iden-tified several novel DOT1B interactors. One of these was the RNase H2 complex, previously shown to resolve RNA-DNA hybrids, maintain genome integrity, and play a role in antigenic variation. Our study revealed that DOT1B depletion results in an increase in RNA-DNA hybrids, accumulation of DNA damage, and ES switch-ing events. Surprisingly, a similar pattern of VSG deregulation was observed in RNase H2 mutants. We propose that both proteins act together in resolving R-loops to ensure genome integrity and contribute to the tightly regulated process of anti-genic variation.}, language = {en} } @article{AdolfiDuKneitzetal.2021, author = {Adolfi, Mateus C. and Du, Kang and Kneitz, Susanne and Cabau, C{\´e}dric and Zahm, Margot and Klopp, Christophe and Feron, Romain and Paix{\~a}o, R{\^o}mulo V. and Varela, Eduardo S. and de Almeida, Fernanda L. and de Oliveira, Marcos A. and N{\´o}brega, Rafael H. and Lopez-Roques, C{\´e}line and Iampietro, Carole and Lluch, J{\´e}r{\^o}me and Kloas, Werner and Wuertz, Sven and Schaefer, Fabian and St{\"o}ck, Matthias and Guiguen, Yann and Schartl, Manfred}, title = {A duplicated copy of id2b is an unusual sex-determining candidate gene on the Y chromosome of arapaima (Arapaima gigas)}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-021-01066-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265672}, year = {2021}, abstract = {Arapaima gigas is one of the largest freshwater fish species of high ecological and economic importance. Overfishing and habitat destruction are severe threats to the remaining wild populations. By incorporating a chromosomal Hi-C contact map, we improved the arapaima genome assembly to chromosome-level, revealing an unexpected high degree of chromosome rearrangements during evolution of the bonytongues (Osteoglossiformes). Combining this new assembly with pool-sequencing of male and female genomes, we identified id2bbY, a duplicated copy of the inhibitor of DNA binding 2b (id2b) gene on the Y chromosome as candidate male sex-determining gene. A PCR-test for id2bbY was developed, demonstrating that this gene is a reliable male-specific marker for genotyping. Expression analyses showed that this gene is expressed in juvenile male gonads. Its paralog, id2ba, exhibits a male-biased expression in immature gonads. Transcriptome analyses and protein structure predictions confirm id2bbY as a prime candidate for the master sex-determiner. Acting through the TGF beta signaling pathway, id2bbY from arapaima would provide the first evidence for a link of this family of transcriptional regulators to sex determination. Our study broadens our current understanding about the evolution of sex determination genetic networks and provide a tool for improving arapaima aquaculture for commercial and conservation purposes.}, language = {en} } @phdthesis{Blum2021, author = {Blum, Carina}, title = {A first step to an integral biointerface design for the early phase of regeneration}, doi = {10.25972/OPUS-21211}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212117}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {The implantation of any foreign material into the body automatically starts an immune reaction that serves as the first, mandatory step to regenerate tissue. The course of this initial immune reaction decides on the fate of the implant: either the biomaterial will be integrated into the host tissue to subsequently fulfill its intended function (e.g., tissue regeneration), or it will be repelled by fibrous encapsulation that determines the implant failure. Especially neutrophils and macrophages play major roles during this inflammatory response and hence mainly decide on the biomaterial's fate. For clinically relevant tissue engineering approaches, biomaterials may be designed in shape and morphology as well as in their surface functionality to improve the healing outcome, but also to trigger stem cell responses during the subsequent tissue regeneration phase. The main focus of this thesis was to unravel the influence of scaffold characteristics, including scaffold morphology and surface functionality, on primary human innate immune cells (neutrophils and macrophages) and human mesenchymal stromal cells (hMSCs) to assess their in vitro immune response and tissue regeneration capacity, respectively. The fiber-based constructs were produced either via melt electrowriting (MEW), when the precise control over scaffold morphology was required, or via solution electrospinning (ES), when the scaffold design could be neglected. All the fiber-based scaffolds used throughout this thesis were composed of the polymer poly(ε caprolactone) (PCL). A novel strategy to model and alleviate the first direct cell contact of the immune system with a peptide-bioactived fibrous material was presented in chapter 3 by treating the material with human neutrophil elastase (HNE) to imitate the neutrophil attack. The main focus of this study was put on the effect of HNE towards an RGDS-based peptide that was immobilized on the surface of a fibrous material to improve subsequent L929 cell adhesion. The elastase efficiently degraded the peptide-functionality, as evidenced by a decreased L929 cell adhesion, since the peptide integrated a specific HNE-cleavage site (AAPV-motif). A sacrificial hydrogel coating based on primary oxidized hyaluronic acid (proxHA), which dissolved within a few days after the neutrophil attack, provided an optimal protection of the peptide-bioactivated fibrous mesh, i.e, the hydrogel alleviated the neutrophil attack and largely ensured the biomaterial's integrity. Thus, according to these results, a means to protect the biomaterial is required to overcome the neutrophil attack. Chapter 4 was based on the advancement of melt electrowriting (MEW) to improve the printing resolution of MEW scaffolds in terms of minimal inter-fiber distances and a concomitant high stacking precision. Initially, to gain a better MEW understanding, the influence of several parameters, including spinneret diameter, applied pressure, and collector velocity on mechanical properties, crystallinity, fiber diameter and fiber surface morphology was analyzed. Afterward, innovative MEW designs (e.g., box-, triangle-, round , and wall-shaped scaffolds) have been established by pushing the printing parameters to their physical limits. Further, the inter-fiber distance within a standardized box-structured scaffold was successfully reduced to 40 µm, while simultaneously a high stacking precision was maintained. In collaboration with a co-worker of my department (Tina Tylek, who performed all cell-based experiments in this study), these novel MEW scaffolds have been proven to facilitate human monocyte-derived macrophage polarization towards the regenerative M2 type in an elongation-driven manner with a more pronounced effect with decreasing pore sizes. Finally, a pro-adipogenic platform for hMSCs was developed in chapter 5 using MEW scaffolds with immobilized, complex ECM proteins (e.g., human decellularized adipose tissue (DAT), laminin (LN), and fibronectin (FN)) to test for the adipogenic differentiation potential in vitro. Within this thesis, a special short-term adipogenic induction regime enabled to more thoroughly assess the intrinsic pro-adipogenic capacity of the composite biomaterials and prevented any possible masking by the commonly used long-term application of adipogenic differentiation reagents. The scaffolds with incorporated DAT consistently showed the highest adipogenic outcome and hence provided an adipo-inductive microenvironment for hMSCs, which holds great promise for applications in soft tissue regeneration. Future studies should combine all three addressed projects in a more in vivo-related manner, comprising a co-cultivation setup of neutrophils, macrophages, and MSCs. The MEW-scaffold, particularly due to its ability to combine surface functionality and adjustable morphology, has been proven to be a successful approach for wound healing and paves the way for subsequent tissue regeneration.}, subject = {Scaffold }, language = {en} } @article{LuisHorrerPhilippetal.2021, author = {Luis, Werner and Horrer, G{\"u}nther and Philipp, Michael and Lubitz, Katharina and Kuntze-Fechner, Maximilian W. and Radius, Udo}, title = {A General Synthetic Route to NHC-Phosphinidenes: NHC-mediated Dehydrogenation of Primary Phosphines}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {647}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {8}, doi = {10.1002/zaac.202000405}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258016}, pages = {881-895}, year = {2021}, abstract = {The dehydrocoupling of primary phosphines with N-heterocyclic carbenes (NHCs) to yield NHC-phosphinidenes is reported. The reaction of two equivalents of the NHCs Me\(_2\)Im (1,3-dimethylimidazolin-2-ylidene), Me\(_4\)Im (1,3,4,5-tetramethylimidazolin-2-ylidene), iPr\(_2\)Im (1,3-di-iso-propylimidazolin-2-ylidene) and Mes\(_2\)Im (2,4,6-trimethylphenylimidazolin-2-ylidene) with PhPH\(_2\) and MesPH\(_2\) led to the NHC stabilized phosphinidenes (NHC)PAr: (iPr\(_2\)Im)PPh (1), (Mes\(_2\)Im)PPh (2), (Me\(_4\)Im)PPh (3), (Mes\(_2\)Im)PMes (4), (Me\(_2\)Im)PMes (5), (Me\(_4\)Im)PMes (6) and (iPr\(_2\)Im)PMes (7). The reaction of tBuPH\(_2\) with two equivalents of the NHCs afforded the corresponding NHC stabilized parent phosphinidenes (NHC)PH: (iPr\(_2\)Im)PH (8), (Mes\(_2\)Im)PH (9) and (Me\(_4\)Im)PH (10). Reaction of 1 with oxygen and sulfur led to isolation of iPr\(_2\)Im-P(O)\(_2\)Ph (11) and iPr\(_2\)Im-P(S)\(_2\)Ph (12), whereas the reaction with elemental selenium and tellurium gave (NHC)PPh cleavage with formation of (iPr\(_2\)Im)Se (13), iPr\(_2\)ImTe (14) and different cyclo-oligophosphines. Furthermore, the complexes [{(iPr\(_2\)Im)PPh}W(CO)\(_5\)] (15), [Co(CO)\(_2\)(NO){(iPr\(_2\)Im)PPh}] (16) and [(η\(^5\)-C\(_5\)Me\(_2\))Co(η\(^2\)-C\(_2\)H\(_4\)){(iPr\(_2\)Im)PPh}] (17) have been prepared starting from 1 and a suitable transition metal complex precursor. The complexes 16 and 17 decompose in solution upon heating to ca. 80 °C to yield the NHC complexes [Co(iPr\(_2\)Im)(CO)\(_2\)(NO)] and [(η\(^5\)-C\(_5\)Me\(_5\))Co(iPr\(_2\)Im)(η\(^2\)-C\(_2\)H\(_4\))] with formation of cyclo-oligophosphines. The reaction of 1 with [Ni(COD)\(_2\)] afforded the diphosphene complex [Ni(iPr\(_2\)Im)\(_2\)(trans-PhP=PPh)] 18.}, language = {en} } @article{GerovaWickeChiharaetal.2021, author = {Gerova, Milan and Wicke, Laura and Chihara, Kotaro and Schneider, Cornelius and Lavigne, Rob and Vogel, J{\"o}rg}, title = {A grad-seq view of RNA and protein complexes in Pseudomonas aeruginosa under standard and bacteriophage predation conditions}, series = {mbio}, volume = {12}, journal = {mbio}, number = {1}, doi = {10.1128/mBio.03454-20}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259054}, pages = {e03454-20}, year = {2021}, abstract = {The Gram-negative rod-shaped bacterium Pseudomonas aeruginosa is not only a major cause of nosocomial infections but also serves as a model species of bacterial RNA biology. While its transcriptome architecture and posttranscriptional regulation through the RNA-binding proteins Hfq, RsmA, and RsmN have been studied in detail, global information about stable RNA-protein complexes in this human pathogen is currently lacking. Here, we implement gradient profiling by sequencing (Grad-seq) in exponentially growing P. aeruginosa cells to comprehensively predict RNA and protein complexes, based on glycerol gradient sedimentation profiles of >73\% of all transcripts and ∼40\% of all proteins. As to benchmarking, our global profiles readily reported complexes of stable RNAs of P. aeruginosa, including 6S RNA with RNA polymerase and associated product RNAs (pRNAs). We observe specific clusters of noncoding RNAs, which correlate with Hfq and RsmA/N, and provide a first hint that P. aeruginosa expresses a ProQ-like FinO domain-containing RNA-binding protein. To understand how biological stress may perturb cellular RNA/protein complexes, we performed Grad-seq after infection by the bacteriophage ΦKZ. This model phage, which has a well-defined transcription profile during host takeover, displayed efficient translational utilization of phage mRNAs and tRNAs, as evident from their increased cosedimentation with ribosomal subunits. Additionally, Grad-seq experimentally determines previously overlooked phage-encoded noncoding RNAs. Taken together, the Pseudomonas protein and RNA complex data provided here will pave the way to a better understanding of RNA-protein interactions during viral predation of the bacterial cell. IMPORTANCE Stable complexes by cellular proteins and RNA molecules lie at the heart of gene regulation and physiology in any bacterium of interest. It is therefore crucial to globally determine these complexes in order to identify and characterize new molecular players and regulation mechanisms. Pseudomonads harbor some of the largest genomes known in bacteria, encoding ∼5,500 different proteins. Here, we provide a first glimpse on which proteins and cellular transcripts form stable complexes in the human pathogen Pseudomonas aeruginosa. We additionally performed this analysis with bacteria subjected to the important and frequently encountered biological stress of a bacteriophage infection. We identified several molecules with established roles in a variety of cellular pathways, which were affected by the phage and can now be explored for their role during phage infection. Most importantly, we observed strong colocalization of phage transcripts and host ribosomes, indicating the existence of specialized translation mechanisms during phage infection. All data are publicly available in an interactive and easy to use browser.}, language = {en} }