Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 2015. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 8,346-8,357 : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory, United States. Department of Energy. Office of Science, National Science Foundation (U.S.), and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- <p>The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium<named-content content-type='genus-species'>Azospirillum brasilense</named-content>navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile<named-content content-type='genus-species'>A. brasilense</named-content>cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Finally, cell-to-cell clumping may thus license diazotrophy to microaerophilic<named-content content-type='genus-species'>A. brasilense</named-content>cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.</p>
- Published through SciTech Connect., 09/25/2015., "KP1501021", "KP1601010", "ERKP435", "ERKP730", Applied and Environmental Microbiology 81 24 ISSN 0099-2240 AM, and Amber N. Bible; Gurusahai K. Khalsa-Moyers; Tanmoy Mukherjee; Calvin S. Green; Priyanka Mishra; Alicia Purcell; Anastasia Aksenova; Gregory B. Hurst; Gladys Alexandre.
- Funding Information:
- AC05-00OR22725, MCB-0919819, and MCB-1330344
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