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lecture+20+oxygen+and+redox+_color_ - Midterm 2 Wednesday...

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Midterm 2 Covers lectures from February 13 to March 5 Wednesday, March 7 10-10:50 am Scantron and written sections. Calculator and ruler are allowed. Review Session Tuesday, March 6 Wellman 2 5:30-7:30 pm Location: 1130 Hart Last name A-G 2 Wellman Last name H-Z Redox potential & foods Fst104 February 29, 2012 February 23rd 2011 FST104 Sybille Tachon
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O 2 metabolism O 2 tolerance Example organisms Microaerophiles Lactic Acid Bacteria Listeria Campylobacter Facultative anaerobes Bacillus E. coli Lactic Acid Bacteria yes and Strong no Anaerobe Clostridium No Poor Aerobes Pseudomonas Yeast & molds Yes Strong Classification of microbes based on oxygen metabolism yes and Intermediate no Superoxide anion Hydroxyl radical Hydrogen peroxide Oxygen O 2 H 2 O 2 O 2 - . HO H 2 O Oxygen is not itself harmful for the cell O 2 and H 2 O 2 Neutral : diffuse through the membrane Do not accumulate in the cell Not the most toxic O 2 . and HO . Charged: accumulate in the cell Oxidation of thiols, Cys (enzyme inactivation, ex: GK, GAPDH) Peroxidation of membrane lipids Oxidation of cell components DNA damage can be lethal O 2 tolerance: Oxygen as a toxin The toxicity of O 2 is due to its byproducts or ROS
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Enzymatic Where do ROS come from? Non enzymatic Non enzymatic Hydroxyl radical Hydrogen peroxide Fe 2+ Fe 3+ Fenton reaction Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - (neutrophils) NADH Oxidase NADH NAD + . HO H 2 O Auto-oxidation of cofactor NADH NAD + Hydroxyl radical Hydrogen peroxide Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - HO . - H 2 O NADH Oxidase NADH NAD + Strategies to cope with oxygen H 2 O forming oxidase ( Streptococcus and Leuconostoc )
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Hydroxyl radical Hydrogen peroxide Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - HO . - H 2 O NADH Oxidase NADH NAD + Catalase O 2 Strategies to cope with oxygen CATALASE 2H 2 O 2 O 2 + 2H 2 O Hydroxyl radical Hydrogen peroxide Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - HO . - H 2 O NADH Oxidase NADH NAD + Catalase O 2 Peroxidases RH R + Strategies to cope with oxygen Peroxidase H 2 O 2 + R 2H 2H 2 O + R
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Hydroxyl radical Hydrogen peroxide Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - HO . - H 2 O NADH Oxidase NADH NAD + Catalase O 2 Peroxidases RH R + SOD Strategies to cope with oxygen Superoxide Dismutase (Sod) 2O 2 . + 2H + O 2 + H 2 O 2 Hydroxyl radical Hydrogen peroxide Oxygen Superoxide anion O 2 H 2 O 2 O 2 . - HO . - H 2 O NADH Oxidase NADH NAD + Catalase O 2 Peroxidases RH R + SOD Mn 2+ Strategies to cope with oxygen High Manganese concentrations O 2 . + H + + Mn 2+ Mn 2+ + O 2 + H 2 O 2
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O 2 metabolism O 2 tolerance Example organisms Microaerophiles Lactic Acid Bacteria Listeria Campylobacter Facultative anaerobes Bacillus E. coli Lactic Acid Bacteria yes and Strong no Anaerobe Clostridium No Poor Aerobes Pseudomonas
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lecture+20+oxygen+and+redox+_color_ - Midterm 2 Wednesday...

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