| Autor: |
Polerecky, Lubos, Masuda, Takako, Eichner, Meri, Rabouille, Sophie, Vancová, Marie, Kienhuis, Michiel V. M., Bernát, Gabor, Bonomi-Barufi, Jose, Campbell, Douglas Andrew, Claquin, Pascal, Červený, Jan, Giordano, Mario, Kotabová, Eva, Kromkamp, Jacco, Lombardi, Ana Teresa, Lukeš, Martin, Prášil, Ondrej, Stephan, Susanne, Suggett, David, Zavřel, Tomas |
| Předmět: |
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| Zdroj: |
Frontiers in Microbiology; 2/4/2021, Vol. 11, pN.PAG-N.PAG, 15p |
| Abstrakt: |
Unicellular nitrogen fixing cyanobacteria (UCYN) are abundant members of phytoplankton communities in a wide range of marine environments, including those with rapidly changing nitrogen (N) concentrations. We hypothesized that differences in N availability (N2 vs. combined N) would cause UCYN to shift strategies of intracellular N and C allocation. We used transmission electron microscopy and nanoscale secondary ion mass spectrometry imaging to track assimilation and intracellular allocation of 13C-labeled CO2 and 15N-labeled N2 or NO3 at different periods across a diel cycle in Cyanothece sp. ATCC 51142. We present new ideas on interpreting these imaging data, including the influences of pre-incubation cellular C and N contents and turnover rates of inclusion bodies. Within cultures growing diazotrophically, distinct subpopulations were detected that fixed N2 at night or in the morning. Additional significant within-population heterogeneity was likely caused by differences in the relative amounts of N assimilated into cyanophycin from sources external and internal to the cells. Whether growing on N2 or NO3, cells prioritized cyanophycin synthesis when N assimilation rates were highest. N assimilation in cells growing on NO3 switched from cyanophycin synthesis to protein synthesis, suggesting that once a cyanophycin quota is met, it is bypassed in favor of protein synthesis. Growth on NO3 also revealed that at night, there is a very low level of CO2 assimilation into polysaccharides simultaneous with their catabolism for protein synthesis. This study revealed multiple, detailed mechanisms underlying C and N management in Cyanothece that facilitate its success in dynamic aquatic environments. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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