Med micro 8 30am wednesday 29 march 2006 bacterial growth nutrition and death
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Med. Micro. 8:30AM, Wednesday 29 March 2006 Bacterial Growth, Nutrition and Death. Simon Silver e-mail: [email protected] Bacterial cell multiplication . Bacterial growth rate, k dB/dt = kB large k = fast growth; small k = slow growth Generation Time: doubling time, t D

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Med. Micro. 8:30AM, Wednesday 29 March 2006 Bacterial Growth, Nutrition and Death

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Med micro 8 30am wednesday 29 march 2006 bacterial growth nutrition and death

Med. Micro. 8:30AM, Wednesday 29 March 2006Bacterial Growth, Nutrition and Death

Simon Silver

e-mail: [email protected]


Bacterial cell multiplication

Bacterial cell multiplication

  • Bacterial growth rate, k

    • dB/dt = kB

    • large k = fast growth; small k = slow growth

  • Generation Time: doubling time, tD

    • large tD = slow growth; small tD = fast growth


The growth curve

The growth curve

  • Lag phase

  • exponential phase: balanced growth

  • Stationery phase

  • Death

  • Bacterial cell cycle and cell division


Microbial death

Microbial death

  • Sterilization: total inactivation of all living organisms

  • Disinfection: killing organisms on a surface

  • Antiseptic: agent that kills or prevents growth, can be used on body surface

  • Bacteriostatic: reversibly inhibits bacterial multiplication

  • Bactericidal; irreversibly inhibits bacterial multiplication


Requirements for bacterial growth

Requirements for bacterial growth

  • Definition of growth

  • New “state”: VBNC- viable but not culturable

  • Nutritional requirements: water, carbon, nitrogen, phosphorous, sulfur


Bacterial growth

Bacterial growth

  • Physical requirements

  • pH

  • Temperature: Psychrophiles, Mesophiles- pathogens, Thermophiles

  • Salinity

  • Oxygen

  • Nutrients


Metabolism generating energy and synthesizing macromolecules

Metabolism: generating energy and synthesizing macromolecules

  • Fermentation

    • Glycolytic pathway

    • Alternative fates of pyruvate


Respiration

Respiration

  • aerobic respiration

    • molecular oxygen serves as the electron acceptor

  • Anaerobic respiration

    • Organic electron acceptors


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