Sökning: "Diazotroph"

Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet Diazotroph.

1. 1. Environmental conditions governing the distributions of symbiotic and free-living diazotrophic cyanobacteria in two tropical open oceans

   Författare :Marcus Stenegren; Rachel Foster; Bethany Jenkins; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nitrogen fixation; Diazotroph; Cyanobacteria; Symbiosis; DDA; Richelia; Marine Ecology; marin ekologi;

   Sammanfattning : Di-nitrogen (N2) fixation plays a crucial role in oceanic carbon and nitrogen cycles and is important for marine biogeochemistry on regional and global scales. N2-fixing (diazotrophs) cyanobacteria are considered to contribute the most to marine nitrogen fixation, and thereby fuel the surrounding phytoplankton communities with bioavailable ammonia. LÄS MER

3. 2. Regulation of Glutamine Synthetase in the Diazotroph Rhodospirillum rubrum

   Författare :Anders Jonsson; Stefan Nordlund; Karl Forchhammer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; glutamine synthetase; Rhodospirillum rubrum; GlnE; PII; Biochemistry; Biokemi; biokemi; Biochemistry;

   Sammanfattning : The bacterial cell needs ammonia for synthesis of glutamine from glutamate. Only one enzyme is able to catalyze this reaction, namely glutamine synthetase (GS). GS can be regulated both transcriptionally and post-translationally and it is present in all kingdoms of life. LÄS MER

4. 3. Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time

   Författare :Andrea Caputo; Rachel Ann Foster; Monika Quinones Winder; Ramon Massana; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phytoplankton; diatoms; cyanobacteria; diazotrophs; symbiosis; evolution; phylogenetics; confocal microscopy; qPCR; CARD-FISH; tropics; sub-tropics; Marine Ecology; marin ekologi;

   Sammanfattning : Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. LÄS MER

5. 4. Molecular detection of abundance and activity of marine, symbiotic, N2-fixing cyanobacteria

   Författare :Linnéa Ström; Rachel Foster; Daniel Lundin; Katharina Pawlowski; Rehab El-Shehawy; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Diatom Diazotroph Association; Richelia; Iron; Phosphorus; Nitrogen; nifH; pstS; exbB; rnpA; växtfysiologi; Plant Physiology; marinbiologi; Marine Biology;

   Sammanfattning : Marine primary productivity in large parts of the oceans is supported by nitrogen fixers (diazotrophs). Richelia, a genus of multiple closely related species of heterocystous filamentous cyanobacterial diazotrophs, are often found in symbioses with a few genera of diatoms. Several Richelia species: R. euintracellularis, R. LÄS MER

7. 5. Significance of N2 fixing planktonic symbioses for open ocean ecosystems

   Författare :Marcus Stenegren; Rachel A. Foster; Agneta Andersson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; nitrogen fixation; diazotrophs; symbiosis; DDA; cyanobacteria; qPCR; piecewise SEM; microarray; tropics; subtropics; marine; open ocean; Richelia; Calothrix; Marine Ecology; marin ekologi;

   Sammanfattning : Di-nitrogen (N2) fixers, also called diazotrophs, are able to reduce atmospheric N2 into bioavailable nitrogen, giving them an advantage in open ocean regions with low dissolved inorganic nitrogen concentrations. The focus of this thesis are three lineages of symbiotic heterocystous filamentous types (het-1, het-2 and het-3), that associate with several genera of microalgae called diatoms (collectively referred to as Diatom Diazotroph Associations, DDAs). LÄS MER