Abstract
Microorganisms naturally respond to changes in nutritional conditions by adjusting their morphology and physiology. The cellular response of the fission yeast S. pombe to nitrogen starvation has been extensively studied. Here, we report time course metabolomic analysis during one hour immediately after nitrogen starvation, prior to any visible changes in cell morphology except for a tiny increase of cell length per division cycle. We semi-quantitatively measured 75 distinct metabolites, 60% of which changed their level over 2-fold. The most significant changes occurred during the first 15 min, when trehalose, 2-oxoglutarate, and succinate increased, while purine biosynthesis intermediates rapidly diminished. At 30–60 min, free amino acids decreased, although several modified amino acids—including hercynylcysteine sulfoxide, a precursor to ergothioneine—accumulated. Most high-energy metabolites such as ATP, S-adenosyl-methionine or NAD+ remained stable during the whole time course. Very rapid metabolic changes such as the shut-off of purine biosynthesis and the rise of 2-oxoglutarate and succinate can be explained by the depletion of NH4Cl. The changes in the levels of key metabolites, particularly 2-oxoglutarate, might represent an important mechanistic step to trigger subsequent cellular regulations.
Highlights
Microorganisms naturally respond to changes in nutritional conditions by adjusting their morphology and physiology
Cell division was transiently arrested for 15 min after N-starvation (Figure 1B)
To obtain metabolomic data sets, three independent wild-type S. pombe cultures were cultivated at 26 °C in liquid EMM2 medium to mid-log phase (5 × 106 cells/mL)
Summary
Microorganisms naturally respond to changes in nutritional conditions by adjusting their morphology and physiology. About 900 transcripts (~19% of ~4,600 detected), half of which corresponded to stress-responsive genes, were up- or down-regulated more than 3-fold. Such immense change in gene expression occurred as early as one hour after N-starvation, indicating the molecular events occurring during the first hour might be critical for the cellular adaptation. Transcription of stress-related genes increased transiently up to 2 h after N-starvation, followed by a decrease afterwards. Transcription of growth-related genes decreased immediately after N-starvation [5]. 47% of all detected proteins changed their copy numbers over 2-fold and an extensive shift from growth-related proteins to stress-responsive proteins was observed 24 h after N-starvation [5]. We aspire to characterize the direct and immediate metabolic response to N-starvation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
