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Schedule of Activities Session Two

Red Layer Microbial Observatory Biology 507 - In-Lab Workshop Photosynthetic Microbes from Local Rivers & Beyond. Schedule of Activities Session Two. Photosynthesis, Pigments, Archaea Pigment Analysis Set-Up Follow-Up - Last Week Curriculum Discussion/Essay

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Schedule of Activities Session Two

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  1. Red Layer Microbial ObservatoryBiology 507 - In-Lab WorkshopPhotosynthetic Microbes from Local Rivers & Beyond

  2. Schedule of Activities Session Two • Photosynthesis, Pigments, Archaea • Pigment Analysis Set-Up • Follow-Up - Last Week • Curriculum Discussion/Essay • We may or may not have time for each person to use the fluorescence microscope.

  3. Photosynthetic Pigments Location Specific proteins hold in membrane - nonpolar Species-specific proteins define real absorption Naked pigment uses discrete value - e.g. 770 Species-specific proteins alter - e.g. 800, 900 Different methods for naked vs. protein-bound

  4. Chlorophylls (Chl) - Oxygenic Plants - green a and b Algae - green a/b, gold/brown a/c, red a/d Cyanobacteria - green a only All of these, when excited by UV, “fluoresce” or emit light in the red or yellow range.

  5. Accessory Pigments - Oxygenic Carotenes - yellow or red, WIDESPREAD Xanthophylls (brown), phycoerythrin (red)

  6. Bacteriochlorophylls (Bchl) - Anoxygenic Purple bacteria - Bchl a Green bacteria - Bchl c Heliobacteria - Bchl g

  7. Accessory Pigments - Anoxygenic Carotenes - yellow or red, WIDESPREAD Phycocyanin - blue, similar to phycoerythrin Many chemotrophic pathogens have carotenes because these neutralize H2O2.

  8. Isolating Naked Pigments Because nonpolar, organic solvents involved Methanol for research-grade work - GLOVES Acetone acceptable/available - harsh Because cell walls, you will pulverize sample Petroleum ether (jar/hood) - chromatography Data useful for major grouping assignments A spectrophotometer allows one to skip chromatography.

  9. Isolating Protein/Pigments IN Membrane Disrupt cells using just pulverization - expensive Fragmented pigments called “in vivo” Data useful for grouping and species variation

  10. Archaeal “Photosynthesis” - Class By ItselfRemarkably, these are commercially available. Why Unique? Bacteriorhodopsin (Brho) pigment in membrane Light causes Brho to physically move H+ out This generates proton motive force - ATPase NO ETC involved in this process Brho homologous to eukaryotic rhodopsin.

  11. Halophiles 5.5+ M salt - many different ions and pH Evaporation ponds, salt lakes, salted foods Halobacterium = phototropic halophile Many other Halophiles are not photosynthetic. They are simple chemotrophs.

  12. Photosynthesis and Evolution Hot earth and the purple origin theory Ancient earth - 100°C but dark Heat gives off infrared - 900 nm or more Emerging purple Bchl absorb this Human eyes and salty Archaea - speculate all you want.

  13. What does the tree of life support? Green nonsulfur most ancient - purple members Phototrophy evolved many times Chloroplast most similar to Cyanobacteria

  14. Pigment Analysis Set-Up Overview Each team will set up 2-3 different phototrophs You will pulverize the sample in methanol Extract 15 minutes - ice/dark Then streak on chromatography paper, develop And analyze the rest on a spectrophotometer Share class data - need all for web analysis Analyze fluorescence data on web template.

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