1 / 22

Microbial Growth

Microbial Growth. Binary Fission Growth Rate Generation Time E. coli can double every 20 minutes Many Bacteria have 0.5-6 hr Generation Times. Cell Division. FTS proteins Divisome Division septum Default shape –Coccus MRE protein. Growth Curve. Batch Culture Lag Phase

troy-contreras
Download Presentation

Microbial Growth

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Microbial Growth • Binary Fission • Growth Rate • Generation Time • E. coli can double every 20 minutes • Many Bacteria have 0.5-6 hr Generation Times

  2. Cell Division • FTS proteins • Divisome • Division septum • Default shape –Coccus • MRE protein

  3. Growth Curve • Batch Culture • Lag Phase • Log Phase (Exponential) • Stationary Phase • Death Phase • Cryptic Growth

  4. Culture Type • Batch Culture • Continuous Culture • Chemostat

  5. Measuring Bacterial Growth • Total Cell Counts • Direct Microscopic Counts • Petroff-Hauser Counting Chambers • DAPI • Flow Cytometer

  6. Viable Counts • Plate Counts • Spread Plate – Sample Spread on Solid Agar Plates • CFU – colony forming units

  7. Pour Plate • Dilute Sample Suspended into Melted Agar

  8. Dilution 30-300 CFU –countable?

  9. Extinction Dilution • MPN – Most Probable Number

  10. Turbidity Measurement • Spectrophotometer

  11. Controlling Growth • Temperature • Minimum • Optimal • Maximum

  12. Temperature Ranges

  13. Cold Temperatures • Psychrophile • Psychrotolerant • Freezing • Preserves Bacterial Cultures • 15 C Optimal • Maximum 20 C

  14. Thermophiles • Thermophile • Optimal 45 C+ • Hyperthermophile • Optimal 80 C+ • Bacteria 95 C • Archaea 100 C+ • Hot Springs

  15. Other Factors pH Low pH Used to Preserve Foods Acidophiles Alkaliphiles Buffers Used in Many Bacteriological Media (Proteins or PO4)

  16. Water Availability • Drying Limits Bacterial Growth • Halophiles • Osmophiles • Xerophiles

  17. Oxygen • Aerobe • Anaerobes • Obligate vs. Facultative • Microaerophile

  18. Growing Anaerobes Aerotolerant vs. Obligate

  19. Growth Word List Growth Curve Lag Phase, Exponential (log) Phase, Stationary Phase, Death Phase, Cryptic Growth Measuring Growth Total Cell Counts Direct Microscopic Counts Petroff-Hausser Counting Chambers Bacterial Growth Binary fission Growth rate Generation Time Exponential Growth Batch Culture

  20. Growth Word List 2 Controlling Growth Temperature Minimum, Optimal, Maximum Psychrophile (psychrotolerant) Mesophile, Thermophile Viable Count Plate Counts Spread Plate Pour Plate Dilution Extinction Dilution MPN – Most Probable Number Turbidity Measurements Continuous Culture Chemostat

  21. Growth Word List 3 Halophiles Osmophiles Xerophiles Oxygen Aerobes, Anaerobes Facultative Microaerophile Hyperthermophile Freezing pH Acidophile Alkaliphile Buffers Water Activity

More Related