1 GROWTH AND CULTURING OF BACTERIA CHAPTER 6. 2 Growth and Cell Division Growth Binary fission.

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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

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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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