OBSERVING DISSOLVED METABOLITES IN PROCHLOROCOCCUS MARINUS CULTURES ON A DIEL TIMESCALE USING BENZOYL CHLORIDE DERIVATIZATION

Prochlorococcus, a picocyanobacterium adapted to oligotrophic environments and Earth's most abundant photosynthetic organism, fixes CO_2, exuding metabolites essential for neighboring microbes. Studies indicate cellular function and growth align with the 24-hour light/dark cycle, suggesting that metabolic profiles may also exhibit diel rhythmicity. However, previous measurements of metabolites released by Prochlorococcus have focused on single time points, obscuring temporal dynamics, and primarily quantified non-polar metabolites. We aimed to determine whether extracellular metabolites from a high-light adapted strain of Prochlorococcus (MIT9301) exhibit diel rhythmicity over time, using benzoyl chloride derivatization coupled with liquid chromatography-mass spectrometry. Axenic cultures were exposed to diel light/dark cycles, and samples were collected every two hours for 48 hours, for extracellular metabolomic profiles. We quantified 30 unique metabolites, with ~50% showing significant diel oscillations. These include metabolites involved in DNA and protein synthesis, such as glutamic acid, proline, and uridine 5’-monophosphate. We also observed the accumulation of metabolites, like glycine and glutathione, in the extracellular space. These findings underscore the need for high temporal resolution in metabolite studies and raise questions regarding the cellular mechanisms controlling the excretion of nitrogen and phosphorus-containing metabolites in nutrient-poor environments.

Presentation Preference: Poster

Primary Presenter: Natalie Graham, Woods Hole Oceanographic Institution (Natalie.Dreux.Graham@gmail.com)

Authors:

Natalie Graham, Woods Hole Oceanographic Institution  (Natalie.Dreux.Graham@gmail.com)

Kathryn Halloran, Woods Hole Oceanographic Institution  (khalloran@whoi.edu)

Brianna Garcia, Woods Hole Oceanographic Institution  (brianna.garcia@whoi.edu)

Melissa Kido-Soule, Woods Hole Oceanographic Institution  (msoule@whoi.edu)

Rogier Braakman, Massachusetts Institute of Technology  (braakman@mit.edu)

Eli Salcedo, Massachusettes Institute of Technology  (esalcedo@MIT.edu)

Allison Coe, Massachusetts Institute of Technology  (a_coe@MIT.edu)

Penny Chisholm, Massachusetts Institute of Technology  (chisholm@mit.edu)

Elizabeth Kujawinski, Woods Hole Oceanographic Institution  (ekujawinksi@whoi.edu)