B. bigelowii Archives

Evolution and function of the nitroplast - Multiple organelles in eukaryotic cells, including mitochondria, chloroplasts, and nitroplasts, evolved from the integration of endosymbiotic bacteria. In Braarudosphaera bigelowii, the chloroplast fi xes inorganic carbon to produce glucose, which feeds the respiratory chain in mitochondria that produces adenosine triphosphate (ATP), which in turn fuels nitrogen fi xation in the nitroplast. Glucose, ammonia, and ATP generated by the organelles, together with externally incorporated compounds (phosphorous, mineral nutrients, and vitamins), are the building blocks for cell metabolism, resulting in cell growth and division. -- Science

Biochemistry & Organic Chemistry, Biophysics, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Press Release

The Nitroplast Revealed: A Nitrogen-fixing Organelle In A Marine Alga

by Keith CowingApril 20, 2024April 20, 2024

A nitrogen-fixing bacterial endosymbiont of marine algae is evolving into a nitrogen-fixing organelle, or nitroplast, according to a new study, thereby expanding a function that was thought to be exclusively […]

Linear volumetric scaling in the B. bigelowii/UCYN-A symbiosis -- (A) Light microscopy image of the haptophyte B. bigelowii in symbiosis with UCYN-A (scale bar, 2 μm; image courtesy of Wing Kwan Esther Mak and Kyoko Hagino). (B) Upper panel: UCYN-A volume (sublineages UCYN-A1, -A2, and -A3; see inset) as a function of associated haptophyte cell volume; lower panel: chloroplast volume as a function of associated haptophyte cell volume; inset in lower panel: UCYN-A volume vs. chloroplast volume of associated host cells. (C) Composite of catalized reporter deposition fluorescence in situ hybridization (CARD-FISH) images showing the range of sizes of the different UCYN-A sublineages (left images: UCYN-A1 sublineage; middle images: UCYN-3 sublineage; right images: UCYN-A2 sublineage) and their symbiotic haptophyte partners. Images were taken under blue (green-labeled haptophytes with Alexa 488 stain) and green (red-labeled UCYN-A with Alexa 594 stain) excitation wavelengths (STAR Methods) (scale bar, 5 μm). -- Cell

Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Press Release

Evolution In Action? New Study Finds Possibility Of Nitrogen-fixing Organelles

by Keith CowingApril 4, 2024April 4, 2024

Nitrogen is a nutrient essential for all life on Earth. Although nitrogen gas (N2) is plentiful, it is largely unavailable to most organisms without a process known as nitrogen fixation, […]