Nitrogenase Activity and "nifH" Expression in a Marine Intertidal Microbial Mat
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T.F. Steppe [1] [2] ; H.W. Paerl [1]
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[1] University of North Carolina at Chapel Hill
University of North Carolina at Chapel Hill
Township of Chapel Hill, Estados Unidos
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[2] Center of Marine Biotechnology, UMBI, 701 E Pratt Street, Baltimore, USA
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- Localización: Microbial ecology, ISSN-e 1432-184X, ISSN 0095-3628, Vol. 49, Nº. 2, 2005, págs. 315-324
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
N2 fixation, diazotrophic community composition, and organisms actively expressing genes for N2 fixation were examined over at 3−year period (1997–1999) for intertidal microbial mats on a sand flat located in the Rachel Carson National Estuarine Research Reserve (RCNERR) (Beaufort, NC, USA). Specifically, diel variations of N2 fixation in the mats from the RCNERR were examined. Three distinct diel patterns of nitrogenase activity (NA) were observed. NA responses to short-term inhibitions of photosynthesis corresponded to one of the three patterns. High rates of NA were observed during peak O2 production periods for diel experiments during summer months. Different types of NA diel variations correspond to different stages of mat development. Chloramphenicol treatments indicated that the mechanism of protein synthesis supporting NA changed throughout the day. Analysis of mat DNA and RNA gave further evidence suggesting that in addition to cyanobacteria, other functional groups were responsible for the NA observed in the RCNERR mats. The role of microbial diversity in the N2 fixation dynamics of these mats is discussed.
