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Protection of nitrogenase from oxygen in unicellular Cyanobacteria is obtained by temporal separation of photosynthesis and diazotrophy through transcriptional and translational regulations of nitrogenase. But diazotrophs can face environmental situations in which N2 fixation occurs significantly in the light, and we believe that another control operates to make it possible. The night-time shutdown of PSII activity is a peculiar behaviour that discriminates Crocosphaera watsonii WH8501 from any other phototroph, whether prokaryote or eukaryote. This phenomenon is not only due to the plastoquinone pool redox status, and suggests that the sentinel D1 protein, expressed in periods of nitrogen fixation, is inactive. Results demonstrate a tight constraint of oxygen evolution in C. watsonii as additional protection of nitrogenase activity and suggest a possible recycling of cellular components.
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http://dx.doi.org/10.1111/1462-2920.13157 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
Florida Museum of Natural History, University of Florida, Gainesville, FL 32611.
The origin and phylogenetic distribution of symbiotic associations between nodulating angiosperms and nitrogen-fixing bacteria have long intrigued biologists. Recent comparative evolutionary analyses have yielded alternative hypotheses: a multistep pathway of independent gains and losses of root nodule symbiosis vs. a single gain followed by numerous losses.
View Article and Find Full Text PDFEnviron Sci Technol
September 2025
Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China.
Rapidly expanding nascent ecosystems at glacier forefields under climate warming dramatically enhance the terrestrial carbon (C) sink. Microbial C fixation and degradation, closely implicated in nitrogen (N) transformation and plant-soil-microbe interactions, significantly regulate soil C accumulation. However, how shifts in microbial functional potential impact soil C sequestration during vegetation succession remains unclear.
View Article and Find Full Text PDFBiotechnol Bioeng
September 2025
Department of Biosystems Engineering, Auburn University, Auburn, Alabama, USA.
Ensuring sufficient crop yields in an era of rapid population growth and limited arable land requires innovative strategies to enhance plant resilience and sustain, or even improve, growth and productivity despite environmental stress. Besides symbiotic nitrogen fixation, rhizobia may play a central role in sustainable agriculture by alleviating the detrimental effects of ethylene-a key stress hormone in plants-especially under conditions like drought through the deamination of 1-aminocyclopropane-1-carboxylic acid (ACC). In this study, we focused on genetically engineering a new Bradyrhizobium sp.
View Article and Find Full Text PDFChem Rec
September 2025
Millenium Institute on Green Ammonia as Energy Vector, Pontificia Universidad Católica de Chile, Santiago, 7820436, Chile.
Ammonia is one of the most important inputs in the global chemical industry, used primarily in fertilizers and explosives. It is increasingly recognized as a potential energy carrier. Its production is dominated by the Haber-Bosch process, which requires high energy consumption and significant capital investment, and contributes significantly to greenhouse gas emissions.
View Article and Find Full Text PDFBioresour Technol
September 2025
Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China. Electronic address:
Microbial desalination cells (MDCs) have traditionally employed simplified NaCl solutions as feedwater for synchronous desalination and bioenergy recovery. Nevertheless, the specific mechanisms by which MDCs remove complex multi-ions from saline wastewater remain obscure. This study thoroughly investigated ion migration, bioelectrochemical dynamics, and microbial ecological responses across three distinct configurations: monovalent ions - PMDC, divalent cations - CMDC and anions - AMDC.
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