Experiment 2

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Experiment 2
The cultivation of bacteria (1)

• routine cultivation of bacteria

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• Contents
• 1. Media for routine cultivation of bacteria
• 2. Techniques for bacterial cultivation and
• inoculation
• 3. Growth characteristics of bacteria on/in
  different
• media
• 4. Metabolic activities of bacteria
• 5. The physical effect on bacteria and commonly
  
• used sterilizers

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• 1. Media for routine cultivation of bacteria
• Media--- The basic ingredients of media
• include carbon source?nitrogen source?
• inorganic salt ?growth factor and
• distilled water etc.

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• Classification of culture media
• According to function, in general, media can
  be classified five types
• 1. basal medium ( agar plate medium)
• 2. nutrient medium (blood agar plate
  medium)
• 3. selective medium
• 4. differential medium
• 5. anaerobic medium.

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• According to physical properties, media can be
  classified three types
• 1. solid medium ( 1.52.5 of agar)
• agar plate /slant medium
• 2. semi-solid medium (0.30.5 of agar)
• 3. liquid medium

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• 2. Techniques for bacterial inoculation
• Bacterial inoculation is a basic technique of
  microbiology. The operation must be under
  sterile condition.
• 1) isolation cultivation
• 2) pure cultivation

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• 1) Isolation cultivation
• streak a bacterial culture on a nutrient agar
  plate to separate the individual bacterial cells,
  each isolated cell will develop into a pure
  colony after incubation.
• continuous streak method
• quadrant streak dilution method

method
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• 2) Pure cultivation
• transfer a single colony from agar plate or a
  pure slant culture to liquid medium, slant or
  semisolid medium to get a pure culture.

subculture into liquid medium subculture into
agar slant/plate subculture into agar deep tube
(semi-solid)
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• 3. Phenomena of bacterial growth
• on agar plate (on blood agar plate)
• in liquid medium
• in semi-solid medium

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• 1) on agar plate
• observe the isolated colony on the surface of
  nutrient agar plate note size, shape, elevation,
  margin, surface, transparency and pigment (color
  of colony).

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• on agar plate -- colony

Note Size ?? Shape
?? Elevation ?? Margin
?? Surface ?? Transparency ??? Pigment
??
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• on blood agar plate
• observe hemolysis (complete and incomplete)
• phenomena around colony.

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• 3) in liquid medium
• three growth phenomena will be seen
• surface growth pellicle ????
• uniformly turbid ??????
• sediment in bottom ????

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• In liquid medium

surface growth pellicle
uniformly turbid
sediment in bottom
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• 4) in semi-solid medium
• nonmotile organism
• motile organism

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• 4. Metabolic Products and Biochemical Testing

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• Carbohydrate Fermentation Test

?????pH 5(?)-pH7(?)?
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• Methyl Red (MR) Test

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• Voges-Proskauer (VP) Test

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• Indole Test

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• Citrate utilization test

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I M
Vi C test E.coli
- - E.Aerogenes - -

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• Hydrogen Sulfide (H2S ) Production

sulfur amino acid sulfur inorganic compound
Pb2
PbS
H2S
(black )
FeS
Fe2
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• Urease Test

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• 5. The physical effect on bacteria and
• commonly used sterilizers
• 1) Physical factor
• dry?moist?ultraviolet?ultrasonic
  wave 2) Commonly used sterilizers
• autoclave
• dry-air oven
• bacteriological filters

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• Experiment manipulation
• 1. Continuous streak method or quadrant streak
  method
• strain S.aureus or E.coli
• one piece of plate/person
• 2. Observe phenomena of bacterial growth
• on agar plate
• in liquid medium
• in semi-solid medium

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• Experiment report
• 1. Continuous streak method or quadrant streak
• method
• principle
• procedure
• result describe the characteristics of
  colony
• analysis
• 2. Draw phenomena of bacterial growth