Export 3 results:
Sort by: [ Author  (Asc)] Title Type Year
A B C D E F G H I J K [L] M N O P Q R S T U V W X Y Z   [Show ALL]
Landry, DM, Kristiansen S, Palenik BP.  2009.  Molecular characterization and antibody detection of a nitrogen-regulated cell-surface protein of the coccolithophore emiliania huxleyi (prymnesiophyceae). Journal of Phycology. 45:650-659.   10.1111/j.1529-8817.2009.00693.x   AbstractWebsite

Dissolved organic nitrogen (DON) can account for a significant portion of total nitrogen in some aquatic environments, and many species of phytoplankton are able to scavenge nitrogen from this pool especially when inorganic nitrogen is limiting. Emiliania huxleyi (Lohmann) H. W. Hay et H. Mohler is able to use various forms of DON for growth, including several amino acids, purines, and pyrimidines. A cell-surface protein up-regulated in the absence of inorganic nitrogen, NRP1, is hypothesized to play a role in the metabolism of one or more of these organic nitrogen forms. Here, the genomic and cDNA sequence of NRP1 is reported. Structural predictions based on the amino acid sequence suggest a pyridoxal-5'-phosphate-dependent enzyme that may have a role in acquiring nitrogen from amino acids. Further evidence for the function of NRP1 is measured in spent media from nitrogen-limited cultures, which contain NRP1 and have glutaminase and formamidase activity. Field studies using an antibody to NRP1 show that it is expressed in E. huxleyi during bloom conditions in a Norwegian fjord.

Landry, DM, Gaasterland T, Palenik BP.  2006.  Molecular characterization of a phosphate-regulated cell-surface protein from the coccolithophorid, Emiliania huxleyi (Prymnesiophyceae). Journal of Phycology. 42:814-821.   10.1111/j.1529-8817.2006.00247.x   AbstractWebsite

Emiliania huxleyi (Lohmann) Hay et Mohler is a cosmopolitan coccolithophorid that is known to be an excellent competitor for phosphate. A previous survey of cell-surface proteins induced by phosphorus limitation in strain CCMP 374 yielded three abundant proteins. Using CCMP 1516, the strain chosen for genome sequence determination, we report the cDNA, genomic, and amino acid sequence of one cell-surface phosphorus-limitation induced protein and evidence that a second protein is highly similar. The introns within the genomic DNA encoding this cell-surface protein as well as those defined by other phosphate-regulated expressed sequence tags are analyzed. As these proteins are the most abundant cell-surface proteins present under phosphorus limitation, they likely have a role in the ability of this organism to compete for phosphate.

Lucas, AJ, Dupont CL, Tai V, Largier JL, Palenik B, Franks PJS.  2011.  The green ribbon: Multiscale physical control of phytoplankton productivity and community structure over a narrow continental shelf. Limnology and Oceanography. 56:611-626.   10.4319/lo.2011.56.2.0611   AbstractWebsite

Chlorophyll concentration, phytoplankton biomass, and total and nitrate-fueled primary productivity increase toward the coast over the 12-km-wide continental shelf of the southern portion of the Southern California Bight. These gradients are accompanied by changes in phytoplankton community composition: the outer shelf is characterized by offshore assemblages including pelagophytes and oligotrophic Synechococcus ecotypes while the inner shelf is dominated by diatoms, coastal Synechococcus ecotypes, and the picoeukaryote Ostreococcus. Across the small horizontal scale of the shelf, large changes in the vertical distribution and flux of nitrate maintain elevated productivity, driving variability in the vertical distribution of biomass and the integrated biomass and productivity of the entire shelf. Temporal variability from hours to days in chlorophyll fluorescence as measured by an autonomous profiling vehicle demonstrates that phytoplankton respond vigorously and rapidly to physical variability. The interaction of physical processes at different temporal and spatial scales is responsible for the observed biological gradients. These dynamics include: (1) vertical shear in the alongshore currents, (2) local wind forcing, (3) the internal tide, and (4) remote, large-scale variability. Individually, these mechanisms rarely or never explain the phytoplankton community composition and metabolic rate gradients. These results and a reanalysis of historical data suggest that monitoring thermal stratification at the shelf break and the tilt of the thermocline across the shelf will augment our ability to predict phytoplankton productivity, community composition, and biomass, thereby improving our understanding of fisheries dynamics and carbon cycling in the coastal ocean.