Biology subjects

Ueberschaar, N.

Publications and source records attributed to Ueberschaar, N..

5 recordsLinked to original sources

bioRxiv2026

Systemic stress states are reversed by NPBWR1 inhibition

Chronic stress is widely studied as a brain-centered driver of depression, yet its effects across the body remain unclear. Here, we define chronic stress as a coordinated molecular state across tissues in mice. Using a whole-body proteomic atlas of 13 tissues, we find that stress effects are strongest in peripheral metabolic and endocrine organs, whereas classical stress-associated brain regions show comparatively modest changes. Cross-organ analyses reveal structured, tissue-specific responses rather than uniform shifts. Inhibition of the stress-regulated receptor NPBWR1 reverses both behavioral deficits and proteomic alterations across organs in both sexes, indicating that this state is dynamically modifiable. Integration with human serum proteomics identifies shared, sex-specific signatures. Across tissues, lipid metabolism emerges as a common stress-responsive pathway, confirmed by hepatic lipid remodeling that is normalized by NPBWR1 inhibition. To facilitate exploration of these data, we provide an interactive cross-organ web-based resource. Together, these findings challenge the brain-centric view of stress pathology and define chronic stress as an organism-wide molecular state.

systems biology↗

bioRxiv2024

Current-use and legacy contaminants evidence dissolved organic matter transfer and dynamics across a fractured-rock groundwater recharge area

Anthropogenic activities cause the release of vast amounts of contaminants into the environment which eventually reach even groundwater resources. With usually sparse regulatory monitoring of limited priority compounds, the large spectrum of contaminants, and the intricacies of intra- and inter-annual contaminant dynamics, such as the emergence and mobilisation of contaminants, are easily overlooked. Utilizing an 6-year record of untargeted LC-MS assessment of dissolved organic, we report the detection and tracing of selected environmental chemicals in the Hainich Critical Zone Exploratory (central Germany), representing a model groundwater flow system under different land use. The insect repellent DEET (N,N-diethyl-m-toluamide) and the coniferous resin acid 7-ODAA (7-oxodehydroabietic acids) show phases of seasonal dynamics in line with their expected periods of release. The legacy herbicides simazine, the triazine transformation product hydroxypropazine, and the flame retardant/plasticiser TPP (triphenyl phosphate) occurred episodically at various locations in the fractured sedimentary bedrock. Within the period of monitoring, extreme weather events (i.e., the severe 2018 drought) and extreme subsurface responses (i.e., 5-year groundwater highstand 2018) likely contributed to long-term organic matter dynamics, potentially causing re-emergence of legacy agrochemicals. This investigation points to the persistence and mobilisation of anthropogenic contaminants, and highlights the importance of long-term combined untargeted and targeted analysis of the groundwater dissolved organic matter for understanding subsurface ecosystems processes. The results add a note of caution for regulatory monitoring since also legacy contaminant levels may considerably vary over time. HighlightsO_LI6 years of monitoring with non-target LC-MS screenings; 4-weekly samplings C_LIO_LI5 current-use and legacy compounds that evidence dissolved organic matter transfer C_LIO_LICompounds comprise regularly targeted and non-monitored features in groundwater C_LIO_LIPronounced phases of non-detects help to further investigate surface-subsurface coupling C_LIO_LIThis illustrates the need for spatiotemporally highly resolved non-target monitoring C_LI

biochemistry↗

bioRxiv2022

Groundwater metabolome responds to recharge in fractured sedimentary strata

Understanding the sources, structure and fate of dissolved organic matter (DOM) in groundwater is paramount for protection and sustainable use of this vital resource. On its passage through the Critical Zone, DOM is subject to biogeochemical conversions. Therefore, it carries valuable cross-habitat information for monitoring and predicting the stability of groundwater ecosystem services and assessing these ecosystems response to fluctuations caused by external impacts such as climatic extremes. Challenges arise from insufficient knowledge on groundwater metabolite composition and dynamics due to a lack of consistent analytical approaches for long-term monitoring. Our study establishes groundwater metabolomics to decipher the complex biogeochemical transport and conversion of DOM. We explore fractured sedimentary bedrock along a hillslope recharge area by a 5-year untargeted metabolomics monitoring of oxic perched and anoxic phreatic groundwater. A summer with extremely high temperatures and low precipitation was included in the monitoring. Water was accessed by a sampling well-transect and regularly collected for liquid chromatography-mass spectrometry (LC-MS) investigation. Dimension reduction of the resulting complex data set by principal component analysis revealed that metabolome dissimilarities between distant wells coincide with transient cross-stratal flow indicated by groundwater levels. Time series of the groundwater metabolome data provides detailed insights into subsurface responses to recharge dynamics. We demonstrate that dissimilarity variability between groundwater bodies with contrasting aquifer properties coincides with recharge dynamics. This includes groundwater high- and lowstands as well as recharge and recession phases. Our monitoring approach allows to survey groundwater ecosystems even under extreme conditions. The metabolome was otherwise highly variable lacking seasonal patterns and did not segregate by geographic location of sampling wells, thus ruling out vegetation or (agricultural) land use as primary driving factor. Patterns that emerge from metabolomics monitoring give insight into subsurface ecosystem functioning and water quality evolution, essential for sustainable groundwater use and climate change-adapted management.

biochemistry↗

bioRxiv2021

Niche separation in cross-feeding sustains bacterial strain diversity across nutrient environments and may increase chances for survival in nutrient-limited leaf apoplasts

The leaf microbiome plays a crucial role in plants health and resilience to stress. Like in other hosts, successful colonization is dependent on multiple factors, among them, resource accessibility. The apoplast is an important site of plant-microbe interactions where nutrients are tightly regulated. While leaf pathogens have evolved elaborate strategies to obtain nutrients there, it is not yet clear how commensals survive without most of these adaptations. Resource limitation can promote metabolic interactions, which in turn shape and stabilize microbiomes but this has not been addressed in detail in leaves. Here, we investigated whether and how the nutrient environment might influence metabolic exchange and assembly of bacterial communities in Flaveria trinervia and F. robusta leaves. We enriched bacteria from both plant species in-vitro in minimal media with sucrose as a carbon source, and with or without amino acids. After enrichment, we studied the genetic and metabolic diversity within the communities. Enriched Pseudomonas koreensis strains could cross-feed from diverse leaf bacteria. Although P. koreensis could not utilize sucrose, cross-feeding diverse metabolites from Pantoea sp ensured their survival in the sucrose-only enrichments. The Pseudomonas strains had high genetic similarity ([~]99.8% ANI) but still displayed clear niche partitioning, enabling them to simultaneously cross-feed from Pantoea. Interestingly, cross-feeders were only enriched from F. robusta and not from F. trinervia. Untargeted metabolomics analysis of the leaf apoplasts revealed contrasting nutrient environments, with greater concentrations of high-cost amino acids in F. trinervia. Additionally, P. koreensis strains were better able to survive without a cross-feeding partner in these richer apoplasts. Thus, cross feeding might arise as an adaptation to cope with nutrient limitations in the apoplast. Understanding how apoplast resources influence metabolic interactions could therefore provide plant breeders targets to manipulate leaf microbiome shape and stability.

microbiology↗

bioRxiv2021

Gram-positive bacteria secrete RNA aptamers to activate human STING for IL-1β release.

Molecular mechanisms through which Gram-positive bacteria induce the canonical inflammasome are poorly understood. Here, we studied the effects of Group B streptococci (GBS) and Staphylococcus aureus (SA) on inflammasome activation in human macrophages. Dinucleotide binding small RNA aptamers released by SA and GBS were shown to trigger increased IL-1{beta} generation by inflammasomes. The stimulator of interferon genes-STING as a central mediator of innate immune responses has been identified as the key target of pathogenic RNA. Multi-lamellar lipid bodies (MLBs) produced by SA function as vehicles for the RNA aptamers. Notably, expression of RNA aptamers is controlled by an accessory gene regulator quorum sensing system of the bacteria. These findings have been translated to patients with Gram-positive sepsis showing hallmarks of MLB-RNA-mediated inflammasome activation. Together our findings may provide a new perspective for the pathogenicity of Gram-positive bacterial infection in man.

immunology↗