Project description:<p>Understanding biogeochemical conversions of dissolved organic matter (DOM) in aquifers is paramount for the effective management of groundwater supplies. On its passage through the critical zone, DOM is subject to biogeochemical conversions and therefore carries cross-habitat information useful for monitoring and predicting the stability of groundwater ecosystem services. Groundwater metabolomics assesses this information. However, challenges arise from insufficient knowledge on groundwater metabolite composition and dynamics, and the necessity to maintain analytical conditions for long-term monitoring. We explored fractured sedimentary bedrock by 5-year untargeted metabolomics monitoring for oxic perched and anoxic phreatic sites along a hillslope recharge area, to evaluate DOM as groundwater tracer. Dimension reduction by principal component analysis revealed that metabolome dissimilarities between distant wells coincide with transient cross-stratal flow indicated by groundwater levels and environmental tracers. The metabolome was highly variable lacking seasonal patterns, and did not segregate by geographic location of sampling wells thus ruling out surface vegetation or (agricultura) land use as driving factor. The metabolome time series provide detailed insights into subsurface responses to recharge dynamics. Metabolomics monitoring provides information on groundwater flows, and allows concluding about below ground ecology and water quality evolution, required to understand the impact of interannual wet-dry cycles.</p>
Project description:Groundwater-derived microorganisms are known to play an important role in biogeochemical C, S and N cycling. Thereby, the presence and majorly the activity of microorganisms in aquifers affect enormously the nutrient cycling. However, the diversity and their functional capability in natural aquifers are still rare and therefore a better knowledge of the core microbial communities is urgently needed. Metaproteome analysis was applied to characterize the repertoire of microbes in the depth and to identify the key drivers of major biogeochemical processes. Therefore, 1000 L water from the aquifer was sampled by filtration on 0.3 µm glass filters. After protein extraction, proteolytic cleavage and mass spectrometric analysis (Ultimate 3000 nanoRSLC coupled to Q Exactive HF instrument), 3808 protein groups (2371 proteins with ≥2 peptides) were identified from 13,204 peptides. The findings of our study have broad implications for the understanding of aquifer cycling’s which finally leads to a greatly improved understanding of the ecosystem services provided by the microbial communities present in aquifers. In the future, functional results would allow to monitor and to assess pollution effects which would beneficially assist groundwater resource management.
Project description:The ecophysiology of complete ammonia oxidizing Nitrospira (CMX) and their widespread occurrence in groundwater suggests that CMX bacteria have a competitive advantage over ammonia-oxidizing bacteria (AOB) and archaea (AOA) in these environments. However, the relevance of their activity from the ecosystem-level process perspective has remained unclear. We investigated oligotrophic carbonate rock aquifers as a model system to assess the contribution of CMX, AOA and AOB to nitrification and to identify the environmental drivers of their niche differentiation at different levels of ammonium and oxygen. CMX accounted for up to 95% of the ammonia oxidizer communities. Nitrification rates were positively correlated to CMX clade A-associated phylotypes and AOB affiliated with Nitrosomonas ureae. Surprisingly, short-term incubations amended with the nitrification inhibitors allylthiourea and chlorate suggested that AOB contributed more than 90% to overall ammonia oxidation, while metaproteomics analysis confirmed an active role of CMX in both ammonia and nitrite oxidation. Ecophysiological niche differentiation of CMX clades A and B, AOA and AOB was linked to their requirements for ammonium, oxygen tolerance, and metabolic versatility. Our results demonstrate that despite numerical predominance of CMX, the first step of nitrification in oligotrophic groundwater is primarily governed by AOB. Higher growth yields at lower NH4+ turnover rates and energy derived from nitrite oxidation most likely enable CMX to maintain consistently high populations. Activity measurements combined with differential inhibition allowed a refined understanding of ammonia oxidizer coexistence, competition and cooperation beyond the insights from molecular data alone.
Project description:TH2 and innate lymphoid cells 2 (ILC2) can stimulate tumor growth by secreting pro-tumorigenic cytokines such as IL4, IL5 and IL13. However, the mechanisms by which type 2 immune cells traffic to the tumor microenvironment (TME) are unknown. Here, in pancreatic ductal adenocarcinoma (PDAC), we show that oncogenic KrasG12D (Kras*) increases the expression of IL33 in cancer cells, which upon secretion recruits and activates the TH2 and ILC2. Correspondingly, cancer cell-specific deletion of IL33 reduces TH2 and ILC2 recruitment and promotes tumor regression. Unexpectedly, we discovered that the cellular release of IL33 into the TME is dependent on the intratumoral fungal mycobiome. Genetic deletion of IL33 or anti-fungal treatment decreases TH2 and ILC2 infiltration and increases survival. Consistent with these murine data, high IL33 expression is observed in approximately 20% of human PDAC, and expression is mainly restricted to cancer cells. These data expand our knowledge of the mechanisms driving PDAC tumor progression and identifies therapeutically targetable pathways involving intratumoral mycobiome-driven secretion of IL33.
Project description:We report the RNAseq of mouse pancreatic cancer cell lines with Kras ON vs Kras OFF. TH2 and innate lymphoid cells 2 (ILC2) can stimulate tumor growth by secreting pro-tumorigenic cytokines such as IL4, IL5 and IL13. However, the mechanisms by which type 2 immune cells traffic to the tumor microenvironment (TME) are unknown. Here, in pancreatic ductal adenocarcinoma (PDAC), we show that oncogenic KrasG12D (Kras*) increases the expression of IL33 in cancer cells, which upon secretion recruits and activates the TH2 and ILC2. Correspondingly, cancer cell-specific deletion of IL33 reduces TH2 and ILC2 recruitment and promotes tumor regression. Unexpectedly, we discovered that the cellular release of IL33 into the TME is dependent on the intratumoral fungal mycobiome. Genetic deletion of IL33 or anti-fungal treatment decreases TH2 and ILC2 infiltration and increases survival. Consistent with these murine data, high IL33 expression is observed in approximately 20% of human PDAC, and expression is mainly restricted to cancer cells. These data expand our knowledge of the mechanisms driving PDAC tumor progression and identifies therapeutically targetable pathways involving intratumoral mycobiome-driven secretion of IL33.
Project description:Gene expression microarrays were performed to investigate the molecular effects of exposure to environmental polluted groundwater. Zebrafish was treated with polluted waters collected from dumps located upstream and downstream a sanitary landfills. Gene expression profiling of zebrafish liver was analyzed after acute exposure to sampled waters.