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GROWTH AND CULTURING OF BACTERIA
CHAPTER 6
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Growth and Cell Division
Growth
Binary fission
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4
Cell Division
Budding
5
Bacterial Growth Curve
Lag phase
Log phase
Stationary phase
Death phase
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Measuring Bacterial Growth Serial dilution/
Standard plate counts
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Measuring Bacterial Growth
Direct microscopic counts
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Measuring Bacterial Growth Most probable
number
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Measuring Bacterial Growth
Filtration
Turbidity (Spectrophotometric)
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Filtration
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Turbidity
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Physical Factors Affecting Bacterial Growth
pH Temperature
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Oxygen
Moisture
Physical Factors Affecting Bacterial Growth
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Hydrostatic pressure
Osmotic pressure
Radiation
Physical Factors Affecting Bacterial Growth
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Radiation:
Ionizing (gamma radiation)
Ultraviolet radiation: DNA absorbs 260 nm light
“Thymine dimers”
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Nutritional Factors Affecting Bacterial Growth
Carbon source
Nitrogen source NH4 best, but NO3 and NO2 can work
too.
Sulfur/ phosphorusPO4
3- SO42-
C6H12O6 best but many sugarsCO2 for autotrophs
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Nutritional Factors Affecting Bacterial Growth
Trace elements
Vitamins
Nutritional complexity
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Tab. 5-1
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Locations of Enzymes
Extracellular
Periplasmic kinases and phosphatases
Cytoplasmic
Proteases and cellulases (hydrolases)
Foldases , dehydrogenases
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Sporulation
Endospores
Other sporelike bacterial structures
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Bacillus subtilis spore stain
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Culturing Bacteria — Streak Plates
Streak plate method
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Culturing Bacteria — Pour Plates
Pour plate method
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Culture Media Types
– Defined
– ComplexLB (Luria-Bertani)TSA
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Culture Media Purposes
Selective media
Differential media
Enrichment media
McConkey’s
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Detection of Carbon source fermenters
McConkey’s agar
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Culture Conditions — O2
Controlling oxygen content
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Culture conditions
Maintaining cultures
Preserved cultures
Diagnostic tests
Limitations
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