Bacteria Eubacteria

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Biology
life
study of
What is Life?
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
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Homeostasis - metabolism
All of these nutritional modes are found among
prokaryotes! Eukaryotes are not as diverse in
their nutritional modes.
3
Photoautotrophs - photosynthesis

• Ancient pathway, but not universal
• Cyanobacteria, Algae, Plants
• light
• CO2 H2O ? O2 CH2O
• chlorophyll
• Purple-sulfur bacteria
• light
• CO2 H2S ? Ss CH2O
• chlorophyll

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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/C
yanobacteria/CBDivideTEM.jpg
RubisCO crystals!
5
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/microb
es2003/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
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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

v
Which of these processes is demonstrating chemoaut
otrophism?
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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/Zd
rs0232.jpg/350px-Zdrs0232.jpg
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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-nodu
le-1.jpg
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Photoheterotrophs - strange

• Bacteria Rhodospirillum, Rhodomicrobium
• Light
• C2H4O2- ? 2 CH2O

spirilloxanthin
http//www.acadweb.wwu.edu/courses/envr429-rm/Robi
n/images/envr429/1_rhodospirillum_600x.jpg
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Chemoheterotrophs - common!

• Escherichia coli and most eukaryoteseven 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!
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Chemoheterotrophy

• Aerobic Respiration
• 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!
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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/C
yanobacteria/CBDivideTEM.jpg
Prokaryotes do not have mitochondriathey became
mitochondria!
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Archea have Homeostasis
Facultative and Obligate Anaerobes and Aerobes
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
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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 Bacteriorhodop
sin Protein retinal Amax 280 UV, 570 green
nm energy for proton transport and
phosphorylation without photosynthesis!
Halobacterium salinarium
http//biology.kenyon.edu/Microbial_Biorealm/ arch
aea/halobacterium/halobacteria_1.jpg
Aerobic Respiration Up to 5 M (25 NaCl)! Great
Salt Lake, Utah Red Sea, Asia Minor
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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/PNA
S96-ZHANG.pd
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Which of these metabolic pathways is
Halobacterium demonstrating?

• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism

v

• Hint
• Light for energy
• Chemicals for carbon

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Methanococcus jannischii
Isolated from white smoker hydrothermal
vent 2600m deep on the East Pacific Rise
http//www.bact.wisc.edu/Bact303/Methanococcus.jpe
g
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Galapagos Islands
East Pacific Rise
http//upload.wikimedia.org/wikipedia/commons/thum
b/a/ae/East_Pacific_Rise.jpg/300px-East_Pacific_Ri
se.jpg
19
http//www.oceanexplorer.noaa.gov/explorations/05g
alapagos/background/mid_ocean_ridge/media/EPR_reli
ef_image_600.jpg
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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 50-86C Other archaeon
species found in cow rumen (first stomach) Cow
belches 50 L of methane per day
http//www.bact.wisc.edu/Bact303/Methanococcus.jpe
g
What does this electron micrograph tell
you? about cell shape? about motility?
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Which of these metabolic pathways is
Methanococcus demonstrating?

• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism

v

• Hint
• H2 for energy
• CO2 for carbon

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Sulfolobus acidocaldarius
75C Optimum Strict aerobe pH 1 to 6 Oxidize
Sulfur or can use Fe2 or MnO42- as electron
acceptorsuses glycolysis and TCA cycle
http//dac.molbio.ku.dk/Sulfolobus.jpg
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Which of these metabolic pathways is Sulfolobus
demonstrating?

• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism

v

• Hint
• Organic chemicals for energy
• Organic chemicals for carbon

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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
  proteinsPyrococcus 121C 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 40C
• Histone-like proteins help stabilize DNA as well
• Heat-resistant di-bi-phytanyl diether lipid
  membranes (monolayer) prevent delamination of
  membrane

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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
If C40, the membrane is a monolayer
In some species, the membrane is a mixture of
both C20 and C40 diglycerides forming a mixed
mono-/bi-layer
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Thermus aquaticus
Gram negative bacterium (not archaeon) Thermophil
e isolated from Yellowstone Hot Spring Optimum
temperature 85C 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/f
ranceschi-projects-30S.html
http//sci.agr.ca/crda/images/BACTERI1.JPG
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Which of these metabolic pathways is Thermus
demonstrating?

• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism

v

• Hint
• Organic chemicals for energy
• Organic chemicals for carbon