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

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

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

Culture Type Batch Culture Continuous Culture Chemostat

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

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

Pour Plate Dilute Sample Suspended into Melted Agar

Dilution CFU –countable?

Extinction Dilution MPN – Most Probable Number

Turbidity Measurement Spectrophotometer

Controlling Growth Temperature Minimum Optimal Maximum

Temperature Ranges

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

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

Other Factors pH Low pH Used to Preserve Foods Acidophiles Alkaliphiles Buffers Used in Many Bacteriological Media (Proteins or PO 4 )

Water Availability Drying Limits Bacterial Growth Halophiles Osmophiles Xerophiles

Oxygen Aerobe Anaerobes Obligate vs. Facultative Microaerophile

Growing Anaerobes Aerotolerant vs. Obligate

Growth Word List Bacterial Growth Binary fission Growth rate Generation Time Exponential Growth Batch Culture 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

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

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