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Item type: Item , Screening of a-amylase/trypsin inhibitor activity in wheat, spelt and einkorn by high-performance thin-layer chromatography(2024) Müller, Isabel; Schmid, Bianca; Bosa, Loredana; Morlock, Gertrud ElisabethItem type: Item , On-surface synthesis – Ullmann coupling reactions on N-heterocyclic carbene functionalized gold nanoparticles(2024) Ukah, Nathaniel; Wegner, Hermann A.Organic on-surface syntheses promise to be a useful method for direct integration of organic molecules onto 2-dimensional (2D) flat surfaces. In the past years, there has been an increasing understanding of the mechanistic details of reactions on surfaces, however, mostly under ultra-high vacuum on very defined surfaces. Herein, we expand the scope to gold nanoparticles (AuNps) in solution via an Ullmann reaction of aryl halides connected via N-heterocyclic carbenes (NHCs) to AuNps. Through design and syntheses of various organic precursors, we address the influence of the contact angle, reactivity of the halogen and the proximity of the entire coupling partner on on-surface reactivities, thus, establishing general parameters governing organic on-surface syntheses on AuNps in solution, in comparison with the reactivity on defined surfaces under ultra-high vacuum. The retention of such halogenated Nps even at higher reaction temperatures holds great promise in the fields of materials engineering, nanotechnology and molecular self-assembly, while expanding the toolbox of organic chemistry synthesis in accessing various covalent architectures.Item type: Item , Exploring the interactions of glyphosate in soil: the sorption scenario upon soil depletion and effect on waterleaf (Talinum triangulare) growth(2024) Diagboya, Paul N.; Olu-Owolabi, Bamidele I.; Düring, Rolf-AlexanderThe pesticide glyphosate has contributed immensely to the ease of farming and high yields. However, the ever-increasing environmental input of pesticides is of particular interest due to several unintended effects on non-target organisms. In soil, the sorption, transport, possible uptake, and effect on plant growth are still not well understood, and much so for the sub-Sahara. Sorption processes are contingent on the soil composition, characteristics, and ambient conditions, and these are becoming increasingly affected by climate change in a way that may alter pesticide fate. Hence, representative sub-Saharan whole soil (WS) treated to eliminate organic matter (OMR) and iron oxides (IOR) was employed to ascertain the contributions of these major constituents to glyphosate sorption processes, as well as ascertain the effect of glyphosate in soil on the growth of Talinum triangulare–waterleaf. Glyphosate sorption for all treatments was rapid with equilibrium at around 720 min. The sorption decreased as pH increased, and was concentration-dependent, gradually increasing with glyphosate concentration. The process was endothermic, and sorption data were better described by the fractal pseudo-second-order and Freundlich adsorption isotherm models, suggesting a complex interplay of interactive sorption forces. The IOR sample (with iron oxide depleted but organic matter intact) exhibited higher sorption than the OMR and WS, highlighting the contribution of organic matter in glyphosate sorption. Hysteresis was high for all samples and increased with temperature. Considering the unregulated usage of glyphosate in the sub-Sahara, the poor sorption, especially in treated soils, observed in this study suggests a high possibility of glyphosate leaching into the aquifer and poisoning of this water source, while the high hysteresis implied the bio-availability of glyphosate in surface soil for plant absorption, hence affecting growth; as confirmed in the waterleaf growth study where growth in the organic-matter/iron-oxide-depleted soils was substantially stunted. Hence, glyphosate affects waterleaf growth, especially in organic-matter/iron-oxide-depleted soils.Item type: Item , Skin Transillumination Improves Peripheral Vein Cannulation by Residents in Neonates: A Randomized Controlled Trial(2024) Hinterstein, Samantha; Ehrhardt, Harald; Zimmer, Klaus-Peter; Windhorst, Anita Cornelia; Kappesser, Judith; Hermann, Christiane; Schuler, Rahel; Waitz, MarkusIntroduction: Establishing peripheral vein access is challenging for pediatric residents and a painful procedure for neonates. We assessed the efficacy of a red light-emitting diode transilluminator during peripheral vein catheter insertion performed by pediatric residents. Methods: Patients were stratified by current weight (≤1,500 g, >1,500 g) and randomized to the transillumination or the control group. The first three attempts were performed by pediatric residents, followed by three attempts by a neonatologist. The primary outcome was success at first attempt. Secondary comparisons included time to successful insertion and overall success rates of residents and neonatologists. Results: A total of 559 procedures were analyzed. The success rate at resident’s first attempt was 44/93 (47%) with transillumination versus 44/90 (49%) without transillumination (p = 0.88) in the strata ≤1,500 g and 103/188 (55%) with transillumination versus 64/188 (34%) without transillumination in the strata >1,500 g (p < 0.001). The overall success rate for residents was 86% in the transillumination versus 73% in the control group in the strata >1,500 g (p = 0.003) but not different in the strata ≤1,500 g (78/93 [84%] vs. 72/90 [80%], p = 0.57). There was no effect when the experience level of residents exceeded 6 months. Neonatologists’ overall success rate and time to successful cannulation did not differ significantly in both weight strata. Conclusion: Transillumination improves the first-attempt success rate of peripheral vein cannulation performed by pediatric residents in neonates >1,500 g, while no benefit was found in infants ≤1,500 g.Item type: Item , The role of small open reading frames in Shewanella oneidensis phage λSo in host takeover and phage proliferation(2025-08) Thöneböhn, Svenja WiebkeBacteriophages are the most abundant biological entities on Earth. They wield an immense influence on microbial ecosystems in almost all habitats by regulating bacterial population dynamics. Most phages follow one of two well-characterised strategies for host exploitation: the lytic or the lysogenic cycle. In both pathways, host cell lysis represents the terminal event and is therefore central to phage fitness. The temperate phage λSo is one of four known prophages in the genome of Shewanella oneidensis MR-1 and has a genome size of about 51 kbp. During lysogeny, λSo remains integrated into the host chromosome, replicating in concert with the host cell. In this study, the lysis system of λSo was characterised as a pinholin-SAR endolysin-two-component spanin pathway. The λSo holin protein, SSo, contains two transmembrane do-mains and also produces an antagonistic isoform through an alternative translation start, named antiholin. This regulatory mechanism enables precise temporal control over the in-itiation of host lysis. In addition to the pinholin and the SAR endolysin, the lysis system requires a two-component spanin complex, made up of an inner membrane protein (i-Spanin, RzSo) and an outer membrane protein (o-Spanin, Rz1So). The corresponding genes are present in an overlapping reading frame structure, and the encoded proteins likely form a functional dimer of two dimers. This putative dimer enables the fusion of the inner and outer membrane. In addition, this work has shown that further, previously uncharacterised gene products are involved in cell lysis. Like many phages, λSo harbours genes encoding small proteins of unknown function. A gene cluster, so called cluster C, was identified, whose deletion significantly reduced the number of plaque-forming units. Cluster C consists of six genes (lcc1 - lcc6) encoding proteins between 41 and 137 amino acids in length that have no obvious homologies to known protein domains. Bioinformatic analysis suggests that Lcc4 and Lcc6 contain putative transmembrane domains. Functional characterisation revealed that Lcc6 plays a critical role in phage-induced host cell lysis. In lcc6 deletion strains, induction of the lytic cycle of λSo using mitomycin C resulted in the formation of phage particles, which, however, failed to lyse the host cells and are therefore not released. These findings suggest that Lcc6 participates in an early phase of the lysis cascade, likely acting in concert with pinholin-mediated membrane disruption. The ectopic expression of the Lcc4 protein on the other hand resulted in a pronounced elongation of the host cells and delocalisation of the FtsZ rings - a phenotype that is compatible with a disruption of cell division. The modelling of plausible protein interactions confirmed that this phenotype results from a direct interaction of Lcc4 with key components of the bacterial divisome, particularly FtsZ and ZipA. Site-directed mutagenesis identified isoleucine residues at positions 16 and 19 as essential for the interaction with FtsZ, and tryptophan 80 and arginine 84 as critical for binding to ZipA. Taken together, these results suggest that Lcc4 specifically inhibits bacterial cytokinesis following prophage induction in order to maximise the availability of the metabolic resources of the host cell during phage replication. The Lcc proteins, encoded by genes of the cluster C, thus represents a previously undescribed phage-host effector system with profound influence on cellular organisation and the course of lysis.