Biology: What is Life? life study of Properties of Life Cellular Structure: the unit of life, one or many Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy Growth: cell enlargement, cell number Movement: intracellular, movement, locomotion Reproduction: avoid extinction at death Behavior: short term response to stimuli Evolution: long term adaptation

Homeostasis - metabolism Nutrition Mode Energy Source Carbon Source Photoautotroph Light CO2 Chemoautotroph Inorganic chem Photoheterotroph Organic chem Chemoheterotroph All of these nutritional modes are found among prokaryotes! Eukaryotes are not as diverse in their nutritional modes.

Photoautotrophs - photosynthesis Ancient pathway, but not universal Cyanobacteria, Algae, Plants light CO2 + H2O  O2 + CH2O chlorophyll Purple-sulfur bacteria CO2 + H2S  Ss + CH2O

Cyanobacterial Vegetative Cell cell wall mesosome cell membrane cyanophycean starch photosynthesis product cyanophycin vacuole lipid droplet polyphosphate granule thylakoids light reactions nucleoid cytosol polyhedral body Calvin cycle and starch synthesis http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg RubisCO crystals!

Artificial coloration of TEM image But thylakoids shown as green would be natural! The location of bacteriochlorophyll! For the light reactions… http://www.jgi.doe.gov/JGI_microbial/images/microbes2003/anava.jpg In a light microscope image: Thylakoids would not be visible, so green color would appear throughout cytosol with nucleoid region lighter in color http://www.bio.utexas.edu/research/utex/photogallery/Anabaena_cylindrica_629.htm

Chemoautotrophs - N metabolism Cyanobacteria, Rhizobium - N2 fixation H+ + ATP + N2  NH4+ Nitrosomonas - nitrification 2 CO2 + NH4+  NO2- + 2 CH2O Pseudomonas - denitrification 2 CH2O + 2 NO2-  N2 + 2 CO2 + 2 H2O √ Which of these processes is demonstrating chemoautotrophism?

Nitrosomonas - internal membranes use NH4+ electrons in an ETS to produce ATP ATP and protons used to reduce CO2 to CH2O http://microbewiki.kenyon.edu/images/thumb/8/89/Zdrs0232.jpg/350px-Zdrs0232.jpg

Rhizobium needs anaerobic conditions to convert N2 into NH4+ Legumes produce heme based molecules and rapid respiration to eliminate oxygen from root nodules that house the bacterium “symbiosis” http://www.interet-general.info/IMG/rhizobium-nodule-1.jpg

Photoheterotrophs - strange Bacteria: Rhodospirillum, Rhodomicrobium Light C2H4O2-  2 CH2O spirilloxanthin http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/1_rhodospirillum_600x.jpg

Chemoheterotrophs - common! Escherichia coli and most eukaryotes…even plants! CH2O + O2  CO2 + H2O + ATP Carbohydrate, etc. provides both the energy source and the carbon source What is another chemoheterotrophic organism? Give the complete Latin binomial!

Chemoheterotrophy Aerobic Respiration CH2O + O2  CO2 + H2O Glycolysis carbohydrate to pyruvate (in cytosol!) Citric Acid Cycle pyruvate to carbon dioxide (in cytosol or matrix) Electron Transport and Oxidative Phosphorylation (in mesosomes or cristae) CH2O + O2  CO2 + H2O Anaerobic Fermentation Glycolysis to pyruvate (in cytosol) Fermentive step(s) to return NAD+ to glycolysis (in cytosol) C6H12O6  C3H3O3-  C2H5OH + CO2 C6H12O6  C3H3O3-  H3CCHOHCOO- Notice how fermentation can produce gas or acids… These are just a few of the fermentive possibilities!

Cyanobacterial Vegetative Cell I thought these were only photosynthetic?? cell wall mesosome electron transport sytem and oxidative phosphorylation cell membrane cyanophycean starch fuel for repiration cyanophycin vacuole lipid droplet fuel for repiration polyphosphate granule thylakoids nucleoid cytosol polyhedral body glycolysis and Krebs cycle http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg Prokaryotes do not have mitochondria…they became mitochondria!

Archea have Homeostasis Facultative and Obligate Anaerobes and Aerobes Nutrition Mode Energy Source Carbon Source Photoautotroph Light CO2 Chemoautotroph Inorganic chem Photoheterotroph Organic chem Chemoheterotroph Photoautotroph Calvin Cycle (Methanococcus, Pyrococcus) Chemoautotroph acetyl-CoA or reverse TCA to fix CO2 Sulfur transporters used to drive ATP synthesis Chemoheterotroph citric acid cycle, fermentation

Replicons have genes for: DNA polymerase Transcription factors 3 chromosomes Main chromosome 2,015 kb 191 kb replicon 366 kb replicon Replicons have genes for: DNA polymerase Transcription factors Mineral uptake (K, PO4) Cell division The genome has many insertion sites for foreign genes Bacteriorhodopsin: Protein + retinal Amax 280 UV, 570 green nm energy for proton transport and phosphorylation without photosynthesis! Halobacterium salinarium http://biology.kenyon.edu/Microbial_Biorealm/ archaea/halobacterium/halobacteria_1.jpg Aerobic Respiration Up to 5 M (25% NaCl)! Great Salt Lake, Utah Red Sea, Asia Minor

Hint: it reflects the other colors of the spectrum Periplasmic space Cell Membrane Retinal lsu.epfl.ch/sh/bR_full.pdf Cytoplasm Bacteriorhodopsin absorbs green from the visible spectrum, so what color is the pigment? Hint: it reflects the other colors of the spectrum www.hawaii.edu/microbiology/ Alam/publications/PNAS96-ZHANG.pd

√ Which of these metabolic pathways is Halobacterium demonstrating? Photoautotrophism Photoheterotrophism Chemoautotrophism Chemoheterotrophism √ Hint: Light for energy Chemicals for carbon

Methanococcus jannischii Isolated from “white smoker” hydrothermal vent 2600m deep on the East Pacific Rise http://epr2004.sr.unh.edu/images/hires/hireswtsmoker.jpg http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg

East Pacific Rise Galapagos Islands http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/East_Pacific_Rise.jpg/300px-East_Pacific_Rise.jpg

http://www. oceanexplorer. noaa http://www.oceanexplorer.noaa.gov/explorations/05galapagos/background/mid_ocean_ridge/media/EPR_relief_image_600.jpg

Methanococcus jannischii Isolated from “white smoker” hydrothermal vent 2600m deep on the East Pacific Rise Methanogen Obligate anaerobe H2 as energy source CO2 as carbon source CH4 as byproduct of metabolism Temperature: 50-86°C Other archaeon species found in cow rumen (first stomach) Cow belches 50 L of methane per day http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg What does this electron micrograph tell you? …about cell shape? …about motility?

√ Which of these metabolic pathways is Methanococcus demonstrating? Photoautotrophism Photoheterotrophism Chemoautotrophism Chemoheterotrophism √ Hint: H2 for energy CO2 for carbon

Sulfolobus acidocaldarius 75°C Optimum Strict aerobe pH 1 to 6 Oxidize Sulfur or can use Fe2+ or MnO42- as electron acceptors…uses glycolysis and TCA cycle http://dac.molbio.ku.dk/Sulfolobus.jpg

√ Which of these metabolic pathways is Sulfolobus demonstrating? Photoautotrophism Photoheterotrophism Chemoautotrophism Chemoheterotrophism √ Hint: Organic chemicals for energy Organic chemicals for carbon

How do Archaea tolerate the heat? Proteins stabilized by more ionic bridges between amino acid r-groups and more-hydrophobic core amino acids Heat shock protein (chaperonins) refold denatured proteins…Pyrococcus 121°C for 1 hour! DNA depurination reduced by presence of 2,3-diphosphoglycerate. DNA supercoiling by reverse gyrase reduces denaturation Sac7d in Sulfolobus is a minor groove protein increases the melting temperature by 40°C Histone-like proteins help stabilize DNA as well Heat-resistant di-bi-phytanyl diether lipid membranes (monolayer) prevent delamination of membrane

Cell Membrane Structure Composed of diglycerides R group may be phosphate, sulfate, or sugar Long chain branched hydrocarbon (not fatty acid) Hydrocarbons may be C20 or C40 If C20, the membrane is a bilayer: O R If C40, the membrane is a monolayer O R In some species, the membrane is a mixture of both C20 and C40 diglycerides forming a mixed mono-/bi-layer

Thermus aquaticus Gram negative bacterium (not archaeon) Thermophile isolated from Yellowstone Hot Spring Optimum temperature 85°C Stability of macromolecules excellent Enzymes for research or commercial use Taq polymerase is the enzyme of PCR (Polymerase Chain Reaction) Lives near cyanobacteria which feed Thermus http://www.molgen.mpg.de/~ag_ribo/ ag_franceschi/franceschi-projects-30S.html http://sci.agr.ca/crda/images/BACTERI1.JPG

√ Which of these metabolic pathways is Thermus demonstrating? Photoautotrophism Photoheterotrophism Chemoautotrophism Chemoheterotrophism √ Hint: Organic chemicals for energy Organic chemicals for carbon