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Bacterial Growth

Bacterial Growth. Introduction Population vs. Cellular Growth Exponential vs. Arithmetic Growth Bacterial Growth - Binary Fission. Bacterial Growth. Bacterial Growth. Bacterial Growth Curve Lag Phase Log Phase Stationary Phase Death Phase. Bacterial Growth. Lag. Stationary. Death.

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Bacterial Growth

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  1. Bacterial Growth • Introduction • Population vs. Cellular Growth • Exponential vs. Arithmetic Growth • Bacterial Growth - Binary Fission

  2. Bacterial Growth

  3. Bacterial Growth • Bacterial Growth Curve • Lag Phase • Log Phase • Stationary Phase • Death Phase

  4. Bacterial Growth Lag Stationary Death Log

  5. Bacterial Growth • Calculations - Number of cells • Example: Initial Cells = Number x 2 number of generations of cells

  6. Bacterial Growth Sample calculation: How many cells would be in a culture if the starting number were 100,000 and the culture was allowed to divide 5 times?

  7. Bacterial Growth • Calculations - Number of Generations • Example: Generations = log n2 – log n1/log 2 Generations = log n2 – log n1/0.301 where n = number of cells at a given time

  8. Bacterial Growth Sample calculation: How many generations have elapsed if the cell count in a culture went from 3 x 108 to 8 x 1010 in 1.5 hours?

  9. Bacterial Growth • Calculations - Generation Time • Time for single cell to double • Example: Elapsed time Generation Time = Number of Generations between n1 and n2

  10. Bacterial Growth • Calculations - Generation Time • Time for single cell to double • Example: 5 hours Generation Time = (Log 1,720,320 – log 100)/.301 = 5/((6.23 – 2)/.301) = .356 hrs or 21 min

  11. Bacterial Growth • Measurement of Growth • Biomass • Viable Counts • Total Counts • Most Probable Number (MPN)

  12. Bacterial Growth • Biomass • Dry weight • Turbidity • Metabolic Activity

  13. Bacterial Growth • Dry Weight • Mass increases in proportion to growth • Filter onto pre-weighed paper • Dry under vacuum • Time consuming but usually accurate

  14. Bacterial Growth • Metabolic Activity • Dissolved oxygen • Decrease in oxygen as cells increase • pH • Use indicator change or pH meter • Monitor a metabolite • Glucose use or ethanol production or carbon dioxide

  15. Bacterial Growth • Viable Counts • Plate counts • Membrane filters

  16. Bacterial Growth • Total Counts • Direct Microscopic Count • Most Probable Number • Electronic Counter

  17. Bacterial Growth • Most Probable Number • 5 tubes at 10 mL, 1 mL and 0.1 mL sized inoculum • Use combinations with table to calculate the most probable number • Confidence limits set range

  18. Bacterial Growth • Electronic counter • Cells move past light source in very narrow tube • Each cell passing is counted • Counts both live and dead cells so must be used before culture gets to stationary phase

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