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Chapter 6, part B

Chapter 6, part B. Microbial Growth. Preserving Bacteria Cultures. Deep-freezing: -50°to -95°C Lyophilization (freeze-drying): Frozen (-54° to -72°C) and dehydrated in a vacuum. Reproduction in Prokaryotes. Binary fission Budding Conidiospores (actinomycetes) Fragmentation of filaments.

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Chapter 6, part B

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  1. Chapter 6, part B Microbial Growth

  2. Preserving Bacteria Cultures • Deep-freezing: -50°to -95°C • Lyophilization (freeze-drying): Frozen (-54° to -72°C) and dehydrated in a vacuum

  3. Reproduction in Prokaryotes • Binary fission • Budding • Conidiospores (actinomycetes) • Fragmentation of filaments

  4. Binary Fission Figure 6.11

  5. Figure 6.12b

  6. If 100 cells growing for 5 hours produced 1,720,320 cells:

  7. Figure 6.13

  8. Figure 6.14

  9. Direct Measurements of Microbial Growth • Plate Counts: Perform serial dilutions of a sample Figure 6.15, top portion

  10. Plate Count • Inoculate Petri plates from serial dilutions Figure 6.16

  11. Plate Count • After incubation, count colonies on plates that have 25-250 colonies (CFUs) Figure 6.15

  12. Direct Measurements of Microbial Growth • Filtration Figure 6.17a, b

  13. Direct Measurements of Microbial Growth • Multiple tube MPN test • Count positive tubes and compare to statistical MPN table. Figure 6.18b

  14. Direct Measurements of Microbial Growth • Direct Microscopic Count

  15. Direct Measurements of Microbial Growth Figure 6.19

  16. Estimating Bacterial Numbers by Indirect Methods • Turbidity Figure 620

  17. Estimating Bacterial Numbers by Indirect methods • Metabolic activity • Dry weight

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