1 / 71

Agouron Microbial Oceanography Summer Course 2007

“Non-oxygenic microbial photophysiologies in the ocean: rhodopsin and bacteriochlorophyll based systems”. Agouron Microbial Oceanography Summer Course 2007. Photophysiology in the sea. N,P,S,Fe…. Respiration. Chemical energy or heat. Animals Bacteria. Solar energy. Photosynthesis.

dmcgrail
Download Presentation

Agouron Microbial Oceanography Summer Course 2007

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. “Non-oxygenic microbial photophysiologies in the ocean: rhodopsin and bacteriochlorophyll based systems” Agouron Microbial Oceanography Summer Course 2007

  2. Photophysiology in the sea N,P,S,Fe…. Respiration Chemical energy or heat Animals Bacteria Solar energy Photosynthesis Plants Algae, photosynthetic bacteria CO2 + H2O carbon water dioxide C6H12O6 + O2 organic oxygen carbon

  3. Dave Karl, Nature, 2002

  4. OTHER SORTS of PHOTOTROPHY

  5. http://ecosystems.mbl.edu/SES/MicrobialMethods/Winogradsky/default.htmhttp://ecosystems.mbl.edu/SES/MicrobialMethods/Winogradsky/default.htm http://helios.bto.ed.ac.uk/bto/microbes/winograd.htm

  6. Winogradsky column O2 H2S

  7. OXYGENIC PAs b a

  8. LOTS OF DIVERSITY IN BACTERIAL ANOXYGENIC PHOTOTROPHS !

  9. General features of anaerobic photosynthetic bacteria Many grow photoorganotrophically in the absence of oxygen When growing phototrophically, derive most of their ATP from light Carbon sources used predominantly for reducing power, biosynthesis Many are capable of photoautotrophic growth

  10. 1% to 6 % of isolates from sand, seaweed, seawater, sediments Tokyo Bay Erythrobacter longus Erythrobacter sp. OCh114. (Roseobacter denitrificans) Roseobacter litoralis

  11. Shimada coined the term in 1995 : “Aerobic anoxygenic phototrophs ” Not capable of anaerobic phototrophic growth; most strict aerobes Wide variety and large amounts of carotenoids Relatively low amounts of bacteriochlorophyll a Appear not able use light as sole source of energy Light-induced oxid./reduct. of photosynthetic apparatus demonstrated Mostly organotrophic (carbon used for energy and as carbon source) Aerobic Anoxygenic Phototrophic Bacteria MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS, Sept. 1998, p. 695ﾐ724. Yurkov and Beatty

  12. “Pump and probe” or Fast repetition rate fluorometry

  13. IRFRR Instrument Vent photosyn !!! Bcll-containing bacteria may contribute 2- 5 % photosynthetic electron transport in the upper ocean

  14. Kolber et al. 2000. Nature 407:178

  15. “Photosynthetically competent anoxygenic phototrophic bacteria comprise at least 11% ofthe total microbial community” Kolber et al. Science 292:2492

  16. P/I curves and CO2 fixation in NAP-1 isolate (a little more controversial…) Kolber et al. Science 292:2492 “Daily cellular rates of CO2 fixation about or 3% of the cellular carbon content...”

  17. Anapleurotic reactions ! • TCA cycle intermediates are used to provide carbon skeletons for other biomolecules. Cycle would halt if OAA is not replaced. • Anapleurotic reactions produce TCA cycle intermediates from pyruvate or PEP.

  18. Oceanic puf M/L phylogeny Béjà, Suzuki, et al. 2002. Nature 415:630-633

  19. BACTERIOCHLOROPHYLL BIOSYNTHETIC GENES in BACTERIOPLANKTON from MONTEREY BAY BEJA et al, 2002 NATURE

  20. Matching Environmental DNA Sequence to Cultured Cell Proteomes:A protein profile of the photosynthetic reaction center of HTCC2080 Courtesy Steve Giovannoni Unpublished: Jang Cho Martha Degan Doug Barofsky Steve Giovannoni HTC Lab (LIONS)/ EHSC Mass Spec Lab Oregon State Univ.

  21. Cho et al.

  22. OM60 and Congregibacter littoralis

  23. HALOARCHAEA

  24. Halobacterium salinarum (electron microscope image)90.5-1.2 um x 1.0-6.0 um in size10 light H+ H+ Purple membrane = 2-D crystalline bacteriorhodopsin lattice ADP flagellae ATP Sensor rhodopsins SR I and SR II ATP-synthase H+

  25. The cycle can be formally described in terms of 6 steps : isomerization (I), ion transport (T), accessibility change (switch S). Retinal first photo-isomerizes from an all-trans to a 13-cis configuration followed by a proton transfer from the Schiff base to the proton acceptor Asp-85. To allow vectoriality, reprotonation of the Schiff base from Asp-85 must be excluded. Thus, its accessibility is switched from extracellular to intracellular. The Schiff base is then reprotonated from Asp-96 in the cytoplasmic channel. After reprotonation of Asp-96 from the cytoplasmic surface, retinal reisomerizes thermally and the accessibility of the Schiff base switches back to extracellular to reestablish the initial state. http://www.biochem.mpg.de/oesterhelt/photobiology/br.html

  26. Genome sequence of Halobacterium species NRC-1 Wailap Victor N et al., PNAS | October 24, 2000 | vol. 97 | no. 22 | 12176-12181

  27. Microbial rhodopsins fall into two different functional classes • Light-driven ion pumps • Sensory rhodopsins

  28. LIBRARY CONSTRUCTION AND SCREENING

  29. SAR86 130 kbp BAC 1 1

  30. “SAR86” 130kb GENOME FRAGMENT

  31. Expression of proteorhodopsin in E. coli Fast photcycle kinetics Oded Beja Béjà et al. Science 289: 1902-1906 (2000)

  32. Phylogenetic distribution of proteorhodopsin variants

  33. Monterey Red Sea Hawaii * * * * SAR86 SUBGROUPS from the COASTAL and OPEN OCEANS Sabehi et al., Environ. Microbiol. 6:903(2004) Do different SAR86 phylotypes encode proteorhodopsins ? Phylogentic relationships of naturally occurring SAR86 ribotypes SSU rRNA ***

  34. de la Torre et al. PNAS 2003

More Related