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Quantifying Oxygen Management and Temperature and Light Dependencies of Nitrogen Fixation by Crocosphaera watsonii
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SYSNO ASEP 0520329 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Quantifying Oxygen Management and Temperature and Light Dependencies of Nitrogen Fixation by Crocosphaera watsonii Author(s) Inomura, K. (US)
Deutsch, C. (US)
Wilson, S.T. (US)
Masuda, Takako (MBU-M) ORCID
Lawrenz, Evelyn (MBU-M) RID
Bučinská, Lenka (MBU-M) RID
Sobotka, Roman (MBU-M) RID, ORCID
Gauglitz, J.M. (US)
Saito, M.A. (US)
Prášil, Ondřej (MBU-M) RID, ORCID
Follows, M.J. (US)Article number e00531-19 Source Title Science Signaling. - : American Association for the Advancement of Science - ISSN 1945-0877
Roč. 4, č. 6 (2019)Number of pages 15 s. Language eng - English Country US - United States Keywords Crocosphaera ; carbon ; cell flux model Subject RIV EE - Microbiology, Virology OECD category Microbiology R&D Projects LO1416 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) GA16-15467S GA ČR - Czech Science Foundation (CSF) Method of publishing Limited access Institutional support MBU-M - RVO:61388971 UT WOS 000506191700004 EID SCOPUS 85076463593 DOI 10.1128/mSphere.00531-19 Annotation Crocosphaera is a major dinitrogen (N-2)-fixing microorganism, providing bioavailable nitrogen (N) to marine ecosystems. The N-2-fixing enzyme nitrogenase is deactivated by oxygen (O-2), which is abundant in marine environments. Using a cellular scale model of Crocosphaera sp. and laboratory data, we quantify the role of three O-2 management strategies by Crocosphaera sp. size adjustment, reduced O-2 diffusivity, and respiratory protection. Our model predicts that Crocosphaera cells increase their size under high O-2. Using transmission electron microscopy, we show that starch granules and thylakoid membranes are located near the cytoplasmic membranes, forming a barrier for O-2. The model indicates a critical role for respiration in protecting the rate of N-2 fixation. Moreover, the rise in respiration rates and the decline in ambient O-2 with temperature strengthen this mechanism in warmer water, providing a physiological rationale for the observed niche of Crocosphaera at temperatures exceeding 20 degrees C. Our new measurements of the sensitivity to light intensity show that the rate of N-2 fixation reaches saturation at a lower light intensity (similar to 100 mu mol m(-2) s(-1)) than photosynthesis and that both are similarly inhibited by light intensities of >500 mu mol m(-2) s(-1). This suggests an explanation for the maximum population of Crocosphaera occurring slightly below the ocean surface.
IMPORTANCE Crocosphaera is one of the major N-2-fixing microorganisms in the open ocean. On a global scale, the process of N-2 fixation is important in balancing the N budget, but the factors governing the rate of N-2 fixation remain poorly resolved. Here, we combine a mechanistic model and both previous and present laboratory studies of Crocosphaera to quantify how chemical factors such as C, N, Fe, and O-2 and physical factors such as temperature and light affect N-2 fixation.Workplace Institute of Microbiology Contact Eliška Spurná, eliska.spurna@biomed.cas.cz, Tel.: 241 062 231 Year of Publishing 2020 Electronic address https://msphere.asm.org/content/4/6/e00531-19
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