Heavy water (D2O) is scarce in nature, and despite its physical similarity to water, D2O disrupts cellular function due to the isotope effect. While microbes can survive in nearly pure D2O, eukaryotes such as Arabidopsis thaliana are more sensitive and are unable to survive higher concentrations of D2O. To explore the underlying molecular mechanisms for these differences, we conducted a comparative proteomic analysis of E. coli, S. cerevisiae, and Arabidopsis after 180 min of growth in a D2O-supplemented media. Shared adaptive mechanisms across these species were identified, including changes in ribosomal protein abundances, accumulation of chaperones, and altered metabolism of polyamines and amino acids. However, Arabidopsis exhibited unique vulnerabilities, such as a muted stress response, lack of rapid activation of reactive oxygen species metabolism, and depletion of stress phytohormone abscisic acid signaling components. Experiments with mutants show that modulating the HSP70 pool composition may promote D2O resilience. Additionally, Arabidopsis rapidly incorporated deuterium into sucrose, indicating that photosynthesis facilitates deuterium intake. These findings provide valuable insights into the molecular mechanisms that dictate differential tolerance to D2O across species and lay the groundwork for further studies on the biological effects of uncommon isotopes, with potential implications for biotechnology and environmental science.

• Keywords
• HSP70, ROS metabolism, adaptation, deuterium oxide, proteome, stress response,
• Publication type
• Journal Article MeSH

Balanced bacterial metabolism is essential for cell homeostasis and growth and can be impacted by various stress factors. In particular, bacteria exposed to metals, including the nanoparticle form, can significantly alter their metabolic processes. It is known that the extensive and intensive use of food and feed supplements, including zinc, in human and animal nutrition alters the intestinal microbiota and this may negatively impact the health of the host. This study examines the effects of zinc (zinc oxide and zinc oxide nanoparticles) on key metabolic pathways of Escherichia coli. Transcriptomic and proteomic analyses along with quantification of intermediates of tricarboxylic acid (TCA) were employed to monitor and study the bacterial responses. Multi-omics analysis revealed that extended zinc exposure induced mainly oxidative stress and elevated expression/production of enzymes of carbohydrate metabolism, especially enzymes for synthesis of trehalose. After the zinc withdrawal, E. coli metabolism returned to a baseline state. These findings shed light on the alteration of TCA and on importance of trehalose synthesis in metal-induced stress and its broader implications for bacterial metabolism and defense and consequently for the balance and health of the human and animal microbiome.

• Keywords
• Carbohydrate metabolism, Nanoparticles, Proteome, Transcriptome, Trehalose synthesis, Tricarboxylic acid cycle, Virulence, Zinc, Zinc oxide,
• MeSH
• Citric Acid Cycle * drug effects   MeSH
• Escherichia coli * metabolism   genetics   drug effects   MeSH
• Adaptation, Physiological MeSH
• Metabolic Networks and Pathways drug effects   MeSH
• Zinc Oxide metabolism   pharmacology   MeSH
• Oxidative Stress MeSH
• Escherichia coli Proteins metabolism   genetics   MeSH
• Proteomics MeSH
• Gene Expression Regulation, Bacterial drug effects   MeSH
• Gene Expression Profiling MeSH
• Transcriptome MeSH
• Trehalose * metabolism   MeSH
• Zinc * metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Zinc Oxide MeSH
• Escherichia coli Proteins MeSH
• Trehalose * MeSH
• Zinc * MeSH