Urea Is Both a Carbon and Nitrogen Source for Microcystis aeruginosa: Tracking 13C Incorporation at Bloom pH Conditions
| Autor: | Brittany N. Zepernick, Steven W. Wilhelm, Lauren E. Krausfeldt, Hector F. Castro Gonzalez, Abigail T. Farmer, Shawn R. Campagna |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Cyanobacteria
HABs Microbiology (medical) Urease lcsh:QR1-502 Microcystin Photosynthesis Algal bloom cyanobacteria Microbiology nitrogen lcsh:Microbiology 03 medical and health sciences chemistry.chemical_compound Microcystis aeruginosa stable isotope probing 030304 developmental biology Lake Erie chemistry.chemical_classification 0303 health sciences biology 030306 microbiology Ammonia volatilization from urea biology.organism_classification chemistry 13. Climate action Environmental chemistry biology.protein Urea |
| Zdroj: | Frontiers in Microbiology, Vol 10 (2019) |
| ISSN: | 1664-302X |
| DOI: | 10.3389/fmicb.2019.01064 |
| Popis: | The use of urea as a nitrogenous fertilizer has increased over the past two decades, with urea itself being readily detected at high concentrations in many lakes. Urea has been linked to cyanobacterial blooms as it is a readily assimilated nitrogen (N) - source for cyanobacteria that possess the enzyme urease. We tested the hypothesis that urea may also act as a carbon (C) source to supplemental growth requirements during the alkaline conditions created by dense cyanobacterial blooms, when concentrations of dissolved CO2 are vanishingly low. High rates of photosynthesis markedly reduce dissolved CO2 concentrations and drive up pH. This was observed in Lake Erie during the largest bloom on record (2015) over long periods (months) and short periods (days) of time, suggesting blooms experience periods of CO2-limitation on a seasonal and daily basis. We used 13C-urea to demonstrate that axenic cultures of the model toxic cyanobacterium, Microcystis aeruginosa NIES843, assimilated C at varying environmentally relevant pH conditions directly into a spectrum of metabolic pools during urea hydrolysis. Primarily, 13C from urea was assimilated into central C metabolism and amino acid biosynthesis pathways, including those important for the production of the hepatotoxin, microcystin, and incorporation into these pathways was at a higher percentage during growth at higher pH. This corresponded to increased growth rates on urea as the sole N source with increasing pH. We propose this ability to incorporate C from urea represents yet another competitive advantage for this cyanobacterium during dense algal blooms. |
| Databáze: | OpenAIRE |
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