Metabolism Lectures

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

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. Agrobacterium 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 Neisseria species www.textbookofbacteriology.net

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

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 Sulfate reducing bacteria www.genomenewsnetwork.org 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 www.cdc.gov/ncidod/eid/vol5no1

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 • 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: • 70-106˚C • 100˚C 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 • It’s an acidiphile • Can be found in acidic mine waters. • Add water to pyrite: • FeS2 −> Fe(III) + H2SO4 • That’s sulfuric acid

Iron mats made by iron oxidizing bacteria

Anoxic photosynthetic iron(II) oxidizing bacteria O2 1 μm Fe2+ NO3−-dependent Fe(II)-oxidizer (Acidovorax sp. strain BoFeN1) Phototrophic Fe(II)-oxidizer (R. ferrooxidans strain SW2) Photos by Professor Andreas Kappler

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

Metabolism Lectures