| Coupled Effects of Light and Nitrogen Source on the Urea Cycle and Nitrogen Metabolism over a Diel Cycle in the Marine Diatom Thalassiosira pseudonana. | |
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MedLine Citation:
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PMID: 21873112 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Diatoms are photoautotrophic organisms capable of growing on a variety of inorganic and organic nitrogen sources. Discovery of a complete urea cycle in diatoms was surprising, as this pathway commonly functions in heterotrophic organisms to rid cells of waste nitrogen. To determine how the urea cycle is integrated into cellular nitrogen metabolism and energy management, the centric diatom Thalassiosira pseudonana was maintained in semi-continuous batch cultures on nitrate, ammonium, or urea as the sole nitrogen source, under a 16: 8 light: dark cycle and at light intensities that were low, saturating, or high for growth. Steady-state transcript levels were determined for genes encoding enzymes linked to the urea cycle, urea hydrolysis, glutamine synthesis, pyrimidine synthesis, photorespiration, and energy storage. Transcript abundances were significantly affected by nitrogen source, light intensity and a diel cycle. The impact of N source on differential transcript accumulation was most apparent under the highest light intensity. Models of cellular metabolism under high light were developed based on changes in transcript abundance and predicted enzyme localizations. We hypothesize that the urea cycle is integrated into nitrogen metabolism through its connection to glutamine and in the eventual production of urea. These findings have important implications for nitrogen flow in the cell over diel cycles at surface ocean irradiances. |
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Authors:
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Sara J Bender; Micaela S Parker; E Virginia Armbrust |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-8-26 |
Journal Detail:
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Title: Protist Volume: - ISSN: 1618-0941 ISO Abbreviation: - Publication Date: 2011 Aug |
Date Detail:
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Created Date: 2011-8-29 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9806488 Medline TA: Protist Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011 Elsevier GmbH. All rights reserved. |
Affiliation:
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Box 357940, School of Oceanography, University of Washington, Seattle, WA, USA. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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