Cyanobacteria Matt, Alex, Megan

Characteristics Photosynthetic autotrophs Get their name from the blue pigment phycocyanin which they use to capture light for photosynthesis. Use the Calvin Cycle as a photosynthetic pathway, just as eukaryotic, higher plants. Previously referred to as “blue green algae, but are not eukaryotic algae.

Characteristics Continued Can fix and convert inert nitrogen to organic forms in heterocysts.

Characteristics Continued Cell walls containing peptidoglycan add strength and counteract osmotic pressure from cytoplasm. Depending on the environment, cyanobacteria colonies form filaments, sheets, or hollow balls. Prokaryotic with an elaborate system of internal membranes useful in photosynthesis— Chlorophyll A and phycobilins (accessory pigments) are embedded in these membranes. Larger than most other bacteria and have remained morphologically similar for billions of years.

History 1 st oxygenic phototrophs on earth Stromatolites: 3.5 billion years Endosymbiotic Theory

Classification Phylogeny poorly understood 35-71% GC; 38-46% in heterocyst formers Define by: colony morphology, reproduction, cell morphology, genetics, habitat, ecology Bergey’s 2 nd edition gave: –57 genera within 5 subgroups

Classification Continued

Examples Oscillatoria: causes Red Sea color Spirulina: food source high in protein Anabaena: symbiosis with Azolla fern Lyngbya: “swimmers itch”

Metabolism Autotrophic so they produce their own food from simple raw materials. Heterocysts allow atmospheric nitrogen to be convert in the anaerobic environment Photosynthesis plays vast role in reproduction and growth. -The wavelength of light absorbed determines what form will grow along with phosphate and iron consumption.

Reproduction Can reproduce many ways: - Binary fission-DNA is duplicated and divided in half. - Budding-Smaller cells form from larger ones. -Fragmentation-Fragments regenerate into complete organism Many ways of reproduction explains the various appearances Cyanobacteria can have. Ie.) slimy masses, strings, filaments, branched filaments…

Habitat Freshwater Wastewater Marine Terrestrial Adaptations –Gliding Motility –Gas Vesicles

Hot Springs

Current Research Wirtz, Nora et al. “Lichen fungi have low cyanobiont selectivity in maritime Antartica.” New Phytologist : Price, G.D. et al. “Identification of an SulP- type bicarbonate transporter in marine cyanobacteria.” PNAS (52):

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