Transcript Slide 1
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 • 1st 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 2nd 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. 2003. 160: 177-183. • Price, G.D. et al. “Identification of an SulPtype bicarbonate transporter in marine cyanobacteria.” PNAS. 2004. 101(52): 18228-18233 The End Hello My Name Is Jeff