Download - Metabolism Lectures
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Metabolism LecturesOutline:
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.
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Bacteria and Archaea
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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.
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Neisseria species
Betaproteobacteria Gram negative, diplococcal Aerobic Most nonmotile N. gonorrhoeae
– VD N. meningitidis
– Spinal meningitis Other Neisseria spp. are
present in respiratory tract of animals.– Most rarely cause disease.
Cultivate on chocolate-blood agar with 3-10% CO2
www.textbookofbacteriology.net
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Pseudomonas species
Gram negative, (Gammaproteobact.) Mostly obligate aerobes
– Some can respire nitrate.
Present in soil, water, plant surfaces Some can degrade pollutants
– TNT for example
Produce secondary metabolites– siderophores or iron binding
molecules
Some produce pigments:– Pyocyanin in P. aeruginosa
Some fluoresce:– P. fluorescence
From: www.bact.wisc.edu/Microtextbook
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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– Seawater
Also abundant in anaerobic environments with lots of decomposing organic matter
www.genomenewsnetwork.org
picasaweb.google.com/sd.gibson
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Campylobacter jejuni
Gram -, (Epsilonproteobact.) Microaerophile Most prevalent food-borne
pathogen in US– Under cooked poultry, pork,
shellfish
Prevalence of contamination:– 90% turkeys– 32% hogs– 89% chickens
www.cdc.gov/ncidod/eid/vol5no1
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Streptococcus Gram positive, Firmicutes Pathogenic and non-pathogenic
kinds Non-pathogenic:
– S. lactis common dairy organism
Oral Streptococcus– 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”
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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
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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:– 70-106˚C– 100˚C is optimum
www.microbeworld.org
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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– It’s an acidiphile
Can be found in acidic mine waters.
Add water to pyrite:– FeS2 −> Fe(III) + H2SO4
– That’s sulfuric acid
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Iron mats made by iron oxidizing bacteria
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Anoxic photosynthetic iron(II) oxidizing bacteria
NO3−-dependent Fe(II)-oxidizer
(Acidovorax sp. strain BoFeN1)Phototrophic Fe(II)-oxidizer(R. ferrooxidans strain SW2)
O2
Fe2+1 μm
Photos by Professor Andreas Kappler
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Fe-mineral coating
2 layers
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Phototrophic Fe(II)-oxidizer Chlorobium ferrooxidans strain KoFox(co-culture with Geospirillum strain)
EncrustedGeospirillum strain
KoFox cells
How can they avoid encrustation?