Lectures
Outline:
Metabolism Part I: Fermentations (Monday)
Part II: Respiration (Wednesday)
Part III: Metabolic Diversity (Friday)
Learning objectives are:
Learn about anaerobic respiratory metabolisms.
How can an inorganic compound be use as an energy source.
Bacteria and Archaea
Agrobacterium species
Alphaproteobacteria
Gram negative rods
Common in soil especially the
root zone of plants
Some are plant pathogens
A. tumefaciens causes crown
galls or plant tumors
Only if A. tumefaciens has
the Ti (tumor inducing)
plasmid.
Elements of Ti have been
engineered to generate
transgeneic plants using.
Neisseria species
Betaproteobacteria
Gram negative, diplococcal
Aerobic
Most nonmotile
N. gonorrhoeae
N. meningitidis
Spinal meningitis
Other Neisseria spp. are
present in respiratory tract of
animals.
VD
Most rarely cause disease.
Cultivate on chocolate-blood
agar with 3-10% CO2
www.textbookofbacteriology.net
Pseudomonas species
Gram negative, (Gammaproteobact.)
Mostly obligate aerobes
Present in soil, water, plant surfaces
Some can degrade pollutants
siderophores or iron binding
molecules
Some produce pigments:
TNT for example
Produce secondary metabolites
Some can respire nitrate.
Pyocyanin in P. aeruginosa
Some fluoresce:
P. fluorescence
From: www.bact.wisc.edu/Microtextbook
Sulfate reducing bacteria
Deltaproteobacteria
Desulfovibrio speices
Strict anaerobes
Generate energy by respiration
of sulfur compounds
Some can use H2 for energy
Many use lactate, acetate, and/or
ethanol as carbon and energy
sources.
Abundant in anaerobic aquatic
environments where sulfate is
high
www.genomenewsnetwork.org
Seawater
Also abundant in anaerobic
environments with lots of
decomposing organic matter
picasaweb.google.com/sd.gibson
Campylobacter jejuni
Gram -, (Epsilonproteobact.)
Microaerophile
Most prevalent food-borne
pathogen US
in Under cooked poultry, pork,
shellfish
Prevalence of contamination:
90% turkeys
32% hogs
89% chickens
www.cdc.gov/ncidod/eid/vol5no1
Streptococcus
Gram positive, Firmicutes
Pathogenic and non-pathogenic
kinds
Non-pathogenic:
Oral Streptococcus
S. lactis common dairy organism
S. salivarius and mutans
Grow on sugars in the mouth
Pathogenic:
S. pyogenes: strains with
hemolysins can cause scarlet
fever
S. pneumoniae: strains with
capsules can cause disease.
Some are flesh eating
Bacteroides
Rod shap, Gram Negative
Strict anaerobe
Dominant microbe in human feces
1010 per gram
Purely fermentative organisms
Normally commensal
Most anaerobic infections are
Bacteroides species.
Big problem in GI tract surgeries
from: microbewiki.kenyon.edu
Pyrococcus fireballs furiosus
Anaerobic, Crenarchaea
Stetter isolated these from
a solfatara field in Vulcano
Italy (1986).
Uses proteins, starch,
sugars, maltose as
electron donors for S0
reductions
Also ferments sugars to H2
and CO2
Growth temps:
70-106C
100C is optimum
www.microbeworld.org
Thiobacillus ferrooxidans
Gamma proteobacteria
4 Fe(II) + 4 H+ + O2 >
4 Fe(III) + 2 H2O
Fe(II) is stable at acidic pH
Does not get oxidized in the
presence of O2
T. ferrooxidans tolerates:
pH ~2.5
Its an acidiphile
Can be found in acidic mine
waters.
Add water to pyrite:
FeS2 > Fe(III) + H2SO4
Thats sulfuric acid
Iron mats made by iron
oxidizing bacteria
Anoxic photosynthetic iron(II) oxidizing bacteria
O2
1 m
NO3-dependent Fe(II)-oxidizer
(Acidovorax sp. strain BoFeN1)
Photos by Professor Andreas Kappler
Fe2+
Phototrophic Fe(II)-oxidizer
(R. ferrooxidans strain SW2)
Fe-mineral coating
2 layers
Phototrophic Fe(II)-oxidizer
Chlorobium ferrooxidans strain KoFox
(co-culture with Geospirillum strain)
KoFox cells
How can they
avoid encrustation?
Encrusted
Geospirillum strain