Metabolism Lectures Outline:  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 –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% CO 2

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:

Sulfate reducing bacteria  Deltaproteobacteria  Desulfovibrio speices  Strict anaerobes  Generate energy by respiration of sulfur compounds  Some can use H 2 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 picasaweb.google.com/sd.gibson

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

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”

Bacteroides  Rod shap, Gram Negative  Strict anaerobe  Dominant microbe in human feces  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 S 0 reductions  Also ferments sugars to H 2 and CO 2  Growth temps: –70-106˚C –100˚C is optimum

Thiobacillus ferrooxidans  Gamma proteobacteria  4 Fe(II) + 4 H + + O 2 −−> 4 Fe(III) + 2 H 2 O  Fe(II) is stable at acidic pH –Does not get oxidized in the presence of O 2  T. ferrooxidans tolerates: – pH ~2.5 –It’s an acidiphile  Can be found in acidic mine waters.  Add water to pyrite: – FeS 2 −> Fe(III) + H 2 SO 4 –That’s sulfuric acid

Iron mats made by iron oxidizing bacteria

Anoxic photosynthetic iron(II) oxidizing bacteria NO 3 − -dependent Fe(II)-oxidizer (Acidovorax sp. strain BoFeN1) Phototrophic Fe(II)-oxidizer (R. ferrooxidans strain SW2) O2O2 Fe 2+ 1 μm Photos by Professor Andreas Kappler

Fe-mineral coating 2 layers

Phototrophic Fe(II)-oxidizer Chlorobium ferrooxidans strain KoFox (co-culture with Geospirillum strain) Encrusted Geospirillum strain KoFox cells How can they avoid encrustation?