1. 1 Growth and Cultivation of bacteria

2. 2 G rowth requirements oxygen (or absence)oxygen (or absence) energyenergy nutrientsnutrients optimal temperatureoptimal temperature optimal pHoptimal pH

3. Oxygen requirements

4. 4 Obligate aerobes grow in presence of oxygen grow in presence of oxygen no fermentation no fermentation oxidative phosphorylation oxidative phosphorylation

5. 5 killed by oxygen fermentation no oxidative phosphorylation lack certain enzymes: superoxide dismutase O 2 - +2H + => H 2 O 2 catalase H 2 O 2 => H 2 0 + O 2 peroxidase H 2 O 2 + NADH + H + => 2H 2 0 + NAD Obligate anaerobes

6. 6 Aerotolerant anaerobes  not killed by oxygen respire anaerobicallyrespire anaerobically

7. 7 Facultative anaerobes fermentationfermentation aerobic respirationaerobic respiration survive in oxygensurvive in oxygen

8. 8 Microaerophilic bacteria growgrow –low oxygen killedkilled –high oxygen

9. Temperature

10. 10 Optimal growth temperature Mesophiles:Mesophiles: –human body temperature * pathogens * opportunists pyschrophilepyschrophile –close to freezing thermophilethermophile –close to boiling

11. 11 pH Many grow best at neutral pH Some can survive/grow - acid - alkali

12. 12 Nutrient Requirements CarbonCarbon NitrogenNitrogen PhosphorusPhosphorus SulfurSulfur Metal ions (e.g. iron)Metal ions (e.g. iron)

13. 13 Siderophores (S) Fe 2+ /S Receptor Transport of iron

14. 14 Measuring bacterial mass (live + dead) in liquid culture Turbidity(Cloudiness)

15. 15 Measuring viable bacteria colony Colony forming units

16. 16 Growth Curve COLONY FORMING UNITS TIME Lag Log Stationary Death

17. 17 Growth Curve TURBIDITY (cloudiness) TIME Lag Log Stationary Autolysis

18. 18 Generation time time for bacterial mass to doubletime for bacterial mass to double ExampleExample 100 bacteria present at time 0 100 bacteria present at time 0 If generation time is 2 hr If generation time is 2 hr After 8 hr mass = 100 x 2 4 After 8 hr mass = 100 x 2 4

19. 19 SUGAR CATABOLISM Glycolysis –Embden Meyerhof Parnas Pathway –most bacteria –also animals and plants

20. 20 Other pathways for catabolizing sugars Pentose phosphate pathway (hexose monophosphate shunt) –generates NADPH –common in plants and animals Entner Doudoroff Pathway –a few bacterial species

21. 21 Glycolysis Glycolysis NADNADH Glucose Pyruvate C6C3 ADPATP

22. 22 Fermentation Pyruvate Pyruvate (C3) NADH NADHNAD Short chain alcohols, fatty acids (C2-C4)

23. 23 Anaerobic Respiration = Glycolysis + Fermentation NADNADH NADH NAD ATP

24. 24 Krebs Cycle (C4-C6 intermediate compounds Krebs Cycle (C4-C6 intermediate compounds ) Pyruvate Pyruvate 3CO 2 (C3) NADNADH NADH NAD Oxidative phosphorylation O2 O2O2 O2 H2OH2OH2OH2O ADP ATP (C1)

25. 25 Aerobic Respiration = Glycolysis + Krebs Cycle/oxidative phosphorylation Pyruvate to CO 2Pyruvate to CO 2 –NAD to NADH –glycolysis –Krebs cycle Oxidative phosphorylationOxidative phosphorylation – NADH to NAD –ADP to ATP

26. 26 Oxidative phosphorylation converts O 2 to H 2 0 (oxidative) converts O 2 to H 2 0 (oxidative) converts ADP to ATP (phosphorylation) converts ADP to ATP (phosphorylation) electron transport chain electron transport chain ubiquinones/cytochrome intermediates ubiquinones/cytochrome intermediates

27. 27 The Krebs cycle Citrate Isocitrate Alpha-keto glutarate Succinate Fumarate Malate Oxaloacetate Pyruvate -CO 2 Acetate + -CO 2 NADH C2 C C C4 X x C6

28. 28 Krebs Cycle - sugar as sole carbon source Pyruvate Acetate -CO 2 C4 Pyruvate + CO 2 + Citrate CC3 Oxalo acetate Oxaloacetate -2CO 2 Aspartic acid Krebscycle ENERGY STORAGE BIOSYNTHESIS C3 C C2 C6 C4 Oxalo acetate X

29. 29 Krebs Cycle – fatty acids as sole carbon source Fatty acids Acetate + Citrate Oxalo acetate -2CO 2 Aspartic acid Krebscycle ENERGY BIOSYNTHESIS Isocitrate Succinate Glyoxylate + Acetate+ Malate Oxalo acetate x C4 C2 C4 C6 -2CO 2 Krebs cycle

30. 30 The Glyoxylate and Krebs cycles Citrate Isocitrate Alpha-keto glutarate Succinate Fumarate Glyoxylate + + Acetate Malate Oxaloacetate 1 2 Krebs cycle onlyGlyoxylate cycle only Krebs and Glyoxylate cycles

31. 31 Krebs Cycle – biosynthetic – energy storage Removal of intermediates Removal of intermediates – must be replenished Unique enzymatic replenishment pathways Unique enzymatic replenishment pathways – sugars – fatty acids

32. Major nutritional types of procaryotes Nutritional TypeEnergy SourceCarbon SourceExamples PhotoautotrophsLightCO 2 Cyanobacteria, some Purple and Green Bacteria PhotoheterotrophsLightOrganic compounds Some Purple and Green Bacteria Chemoautotrophs or Lithotrophs (Lithoautotrophs) Inorganic compounds, e.g. H 2, NH 3, NO 2, H 2 S CO 2 A few Bacteria and many Archaea Chemoheterotrophs or Heterotrophs Organic compounds Most Bacteria, some Archaea