Whole-Cell Immunolocalization of Nitrogenase in Marine Diazotrophic Cyanobacteria, Trichodesmium spp

Release of Dissolved Organic Nitrogen by Marine Diazotrophic Cyanobacteria, Trichodesmium spp.

Trichodesmium sp. is a filamentous, colonial cyanobacterium which contributes substantially to the input of nitrogen in tropical and subtropical oceanic waters through nitrogen fixation (N(2) fixation). We applied a N tracer technique to assess the rate of release of dissolved organic nitrogen (DON) from this cyanobacterium and compared those rates with rates of N(2) fixation determined for the...

Marine diazotrophic cyanobacteria: Out of the blue

Cyanobacteria are now recognized as the primary nitrogen-fixing (diazotrophic) microorganisms in the oceans as contributing significantly to the biogeochemistry of the global nitrogen cycle. The evolution of a remarkable range of morphologies and metabolic capacities has led to a behavioural versatility that helps them to proliferate and combat nutrient limitations in oceanic ecosystems. Advanc...

Circadian Rhythm of Nitrogenase Gene Expression in the Diazotrophic Filamentous Nonheterocystous Cyanobacterium Trichodesmium sp. Strain IMS

Immunochemical localization of nitrogenase in marine trichodesmium aggregates: relationship to n(2) fixation potential.

Colonial aggregation among nonheterocystous filaments of the planktonic marine cyanobacterium Trichodesmium is known to enhance N(2) fixation, mediated by the O(2)-sensitive enzyme complex nitrogenase. Expression of nitrogenase appears linked to the formation of O(2)-depleted microzones within aggregated bacterium-associated colonies. While this implies a mechanism by which nonheterocystous N(2...

Temporal Variability in Nitrogenase Gene Expression in Natural Populations of the Marine Cyanobacterium Trichodesmium thiebautii.

We report a distinct diel periodicity in the abundance of nifH (dinitrogenase reductase) mRNA in natural populations of the nonheterocystous marine cyanobacterium Trichodesmium thiebautii. Our observations show that in addition to translational and posttranslational controls, Trichodesmium nitrogenase expression is also regulated at the transcriptional and/or posttranscriptional level.